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1

Serum metal ion concentrations after unilateral vs bilateral large-head metal-on-metal primary total hip arthroplasty.  

PubMed

It is unknown if the presence of bilateral well-functioning large-head metal-on-metal (MOM) total hip arthroplasties (THAs) leads to higher serum metal ion concentrations than unilateral MOM THA. Elevated levels (chromium, 17 ?g/L; cobalt, 19 ?g/L) have been associated with poorly functioning MOM THA with metallosis. Fourteen patients having undergone bilateral and 25 patients having undergone unilateral large-head primary MOM THA were compared. Harris Hip Scores, University of California Los Angeles activity scores, radiographs, serum creatinine, and serum cobalt and chromium levels were obtained. Only cobalt ion levels were significantly higher in the bilateral group than in the unilateral group (1.8 ?g/L vs 1.0 ?g/L, P = .029). Comparatively, this magnitude is clinically rather low because ion levels did not approach those associated with metallosis in either group. We conclude that although patients with well-functioning bilateral MOM THA may have slightly higher cobalt levels, neither cobalt nor chromium levels approach those seen in poorly functioning MOM THA with metallosis. PMID:21570800

Pelt, Christopher E; Bergeson, Adam G; Anderson, Lucas A; Stoddard, Gregory J; Peters, Christopher L

2011-12-01

2

Large head metal-on-metal cementless total hip arthroplasty versus 28mm metal-on-polyethylene cementless total hip arthroplasty: design of a randomized controlled trial  

PubMed Central

Background Osteoarthritis of the hip is successfully treated by total hip arthroplasty with metal-on-polyethylene articulation. Polyethylene wear debris can however lead to osteolysis, aseptic loosening and failure of the implant. Large head metal-on-metal total hip arthroplasty may overcome polyethylene wear induced prosthetic failure, but can increase systemic cobalt and chromium ion concentrations. The objective of this study is to compare two cementless total hip arthroplasties: a conventional 28 mm metal-on-polyethylene articulation and a large head metal-on-metal articulation. We hypothesize that the latter arthroplasties show less bone density loss and higher serum metal ion concentrations. We expect equal functional scores, greater range of motion, fewer dislocations, fewer periprosthetic radiolucencies and increased prosthetic survival with the metal-on-metal articulation. Methods A randomized controlled trial will be conducted. Patients to be included suffer from non-inflammatory degenerative joint disease of the hip, are aged between 18 and 80 and are admitted for primary cementless unilateral total hip arthroplasty. Patients in the metal-on-metal group will receive a cementless titanium alloy acetabular component with a cobalt-chromium liner and a cobalt-chromium femoral head varying from 38 to 60 mm. Patients in the metal-on-polyethylene group will receive a cementless titanium alloy acetabular component with a polyethylene liner and a 28 mm cobalt-chromium femoral head. We will assess acetabular bone mineral density by dual energy x-ray absorptiometry (DEXA), serum ion concentrations of cobalt, chromium and titanium, self reported functional status (Oxford hip score), physician reported functional status and range of motion (Harris hip score), number of dislocations and prosthetic survival. Measurements will take place preoperatively, perioperatively, and postoperatively (6 weeks, 1 year, 5 years and 10 years). Discussion Superior results of large head metal-on-metal total hip arthroplasty over conventional hip arthroplasty have been put forward by experts, case series and the industry, but to our knowledge there is no randomized controlled evidence. Conclusion This randomized controlled study has been designed to test whether large head metal-on-metal cementless total hip arthroplasty leads to less periprosthetic bone density loss and higher serum metal ion concentrations compared to 28 mm metal-on-polyethylene cementless total hip arthroplasty. Trial registration Netherlands Trial Registry NTR1399 PMID:18842151

Zijlstra, Wierd P; Bos, Nanne; van Raaij, Jos JAM

2008-01-01

3

No association between serum metal ions and implant fixation in large-head metal-on-metal total hip arthroplasty  

PubMed Central

Background The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris. Patients and methods 49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28–68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density. Results At 1–2 years, mean total translation (TT) was 0.04 mm (95% CI: –0.07 to 0.14; p = 0.5) for the stems; at 2–5 years, mean TT was 0.13 mm (95% CI: –0.25 to –0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1–2 and 2–5 years. At 2–5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < –1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)). Interpretation Most cups and stems were well-fixed at 1–5 years. However, at 2–5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the fixation of hip components in large-head MoM articulations at medium-term follow-up. PMID:24847790

Sřballe, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken

2014-01-01

4

Does bearing size influence metal ion levels in large-head metal-on-metal total hip arthroplasty? A comparison of three total hip systems  

PubMed Central

Background The purpose of the study was twofold: first, to determine whether there is a statistically significant difference in the metal ion levels among three different large-head metal-on-metal (MOM) total hip systems. The second objective was to assess whether position of the implanted prostheses, patient demographics or factors such as activity levels influence overall blood metal ion levels and whether there is a difference in the functional outcomes between the systems. Methods In a cross-sectional cohort study, three different metal-on-metal total hip systems were assessed: two monoblock heads, the Durom socket (Zimmer, Warsaw, IN, USA) and the Birmingham socket (Smith and Nephew, Memphis, TN, USA), and one modular metal-on-metal total hip system (Pinnacle, Depuy Orthopedics, Warsaw, IN, USA). Fifty-four patients were recruited, with a mean age of 59.7 years and a mean follow-up time of 41 months (12 to 60). Patients were evaluated clinically, radiologically and biochemically. Statistical analysis was performed on all collected data to assess any differences between the three groups in terms of overall blood metal ion levels and also to identify whether there was any other factor within the group demographics and outcomes that could influence the mean levels of Co and Cr. Results Although the functional outcome scores were similar in all three groups, the blood metal ion levels in the larger monoblock large heads (Durom, Birmingham sockets) were significantly raised compared with those of the Pinnacle group. In addition, the metal ion levels were not found to have a statistically significant relationship to the anteversion or abduction angles as measured on the radiographs. Conclusions When considering a MOM THR, the use of a monoblock large-head system leads to higher elevations in whole blood metal ions and offers no advantage over a smaller head modular system. PMID:24472283

2014-01-01

5

Cementless large-head metal-on-metal total hip arthroplasty in patients younger than 60 years--a multicenter early result.  

PubMed

Large-head metal-on-metal total hip arthroplasty has the theoretical advantages of less wear and better range of motion than traditional polyethylene bearings and seems to be a better choice for young and active patients. We conducted a retrospective study and reported the early results of using such prostheses in 59 patients (70 hips) with a mean age of 43.1 years (range, 23-59 years) at the time of surgery. Osteonecrosis of the femoral head accounted for most diagnoses. Harris Hip Scores and hip range of motion both significantly improved (p<0.001) at an average follow-up of 32.6 months (range, 24-48 months). Only one intraoperative calcar fissure was encountered, and it was fixated by cerclage wiring; there was no infection, dislocation, or osteolysis around either the cup or the stem at the latest follow-up. A postoperative gap in the acetabular component was noted in 24 hips, with a mean depth of 1.11 mm, but this was not correlated with the functional score (p=0.291). Transient thigh pain, which resolved after 6 months, was observed in six patients but was not related to either the postoperative gap or cup inclination (p=1.000 and p=0.664, respectively). All patients resumed their original jobs and recreational activities with little discomfort. Thus far, large-head metal-on-metal total hip arthroplasty has shown excellent early results. The long-term results and the effects of metal debris and potentially elevated serum metal ion levels require further observation. PMID:22226059

Wu, Po-Ting; Wang, Chih-Jen; Yen, Cheng-Yo; Jian, Ji-Shen; Lai, Kuo-An

2012-01-01

6

A comparison of leg length and femoral offset discrepancies in hip resurfacing, large head metal-on- metal and conventional total hip replacement: a case series  

PubMed Central

Background A discrepancy in leg length and femoral offset restoration is the leading cause of patient dissatisfaction in hip replacement surgery and has profound implications on patient quality of life. The aim of this study is to compare biomechanical hip reconstruction in hip resurfacing, large-diameter femoral head hip arthroplasty and conventional total hip replacement. Method Sixty patient's post-operative radiographs were reviewed; 20 patients had a hip resurfacing (HR), 20 patients had a Large Head Metal-on-metal (LHM) hip replacement and 20 patients had a conventional small head Total Hip Replacement (THR). The leg length and femoral offset of the operated and unoperated hips were measured and compared. Results Hip resurfacing accurately restored hip biomechanics with no statistical difference in leg length (P = 0.07) or femoral offset (P = 0.95) between the operated and non-operative hips. Overall HR was superior for reducing femoral offset discrepancies where it had the smallest bilateral difference (-0.2%, P = 0.9). The traditional total hip replacement was least effective at restoring the hip anatomy. Conclusion The use of a larger-diameter femoral head in hip resurfacing does not fully account for the superior biomechanical restoration, as LHM did not restore femoral offset as accurately. We conclude that restoration of normal hip biomechanics is best achieved with hip resurfacing. PMID:22206621

2011-01-01

7

Functional outcome following a large head total hip arthroplasty: A retrospective analysis of mid term results  

PubMed Central

Background: One of the reasons that hip resurfacing and large head metal on metal (MOM) total hip arthroplasty (THA) became popular in Asia was the possible increased range of movement and thereby improved function of the hip joint. Due to concerns of MOM articulation an alternative bearing was sought. Hence, a shift from large head MOM to large head ceramic on ceramic (COC) was made. The aim of this study was to compare the functional outcome including range of motion (ROM) and dislocation rates following large head MOM and large head COC THA. Materials and Methods: Retrospectively, 39 primary THA with large head MOM with a mean age of 56 years (range 36-72 years) and average followup of 54 months (range 38-70 months) were compared with 23 primary THA with large head COC bearing with a mean age of 48 years (range 36-68 years) and an average followup of 18 months (range 12-26 months). Functional outcome was assessed using the Modified Harris Hip Score. Dislocation rate and ROM were compared. Results: Global ROM averaged 248 degrees with MOM group and 252 degrees with the COC group. One patient with metal bearing had dislocation at an average 3 year followup which required revision THA while there were no complications in the COC group. MHHS averaged 89 points in MOM and 94 in COC THR. Conclusion: This study has shown that large head ceramic on ceramic THA is a good alternative to large head metal on metal THA with comparable dislocation rates and range of movements and without complications of metallosis in Asian patients. PMID:25143647

Agarwala, Sanjay; Mohrir, Ganesh; Moonot, Pradeep

2014-01-01

8

Metal-on-Metal Total Hip Resurfacing Arthroplasty  

PubMed Central

Executive Summary Objective The objective of this review was to assess the safety and effectiveness of metal on metal (MOM) hip resurfacing arthroplasty for young patients compared with that of total hip replacement (THR) in the same population. Clinical Need Total hip replacement has proved to be very effective for late middle-aged and elderly patients with severe degenerative diseases of the hips. As indications for THR began to include younger patients and those with a more active life style, the longevity of the implant became a concern. Evidence suggests that these patients experience relatively higher rates of early implant failure and the need for revision. The Swedish hip registry, for example, has demonstrated a survival rate in excess of 80% at 20 years for those aged over 65 years, whereas this figure was 33% by 16 years in those aged under 55 years. Hip resurfacing arthroplasty is a bone-conserving alternative to THR that restores normal joint biomechanics and load transfer. The technique has been used around the world for more than 10 years, specifically in the United Kingdom and other European countries. The Technology Metal-on-metal hip resurfacing arthroplasty is an alternative procedure to conventional THR in younger patients. Hip resurfacing arthroplasty is less invasive than THR and addresses the problem of preserving femoral bone stock at the initial operation. This means that future hip revisions are possible with THR if the initial MOM arthroplasty becomes less effective with time in these younger patients. The procedure involves the removal and replacement of the surface of the femoral head with a hollow metal hemisphere, which fits into a metal acetabular cup. Hip resurfacing arthroplasty is a technically more demanding procedure than is conventional THR. In hip resurfacing, the femoral head is retained, which makes it much more difficult to access the acetabular cup. However, hip resurfacing arthroplasty has several advantages over a conventional THR with a small (28 mm) ball. First, the large femoral head reduces the chance of dislocation, so that rates of dislocation are less than those with conventional THR. Second, the range of motion with hip resurfacing arthroplasty is higher than that achieved with conventional THR. A variety of MOM hip resurfacing implants are used in clinical practice. Six MOM hip resurfacing implants have been issued licences in Canada. Review Strategy A search of electronic bibliographies (OVID Medline, Medline In-Process and Other Non-Indexed Citations, Embase, Cochrane CENTRAL and DSR, INAHTA) was undertaken to identify evidence published from Jan 1, 1997 to October 27, 2005. The search was limited to English-language articles and human studies. The literature search yielded 245 citations. Of these, 11 met inclusion criteria (9 for effectiveness, 2 for safety). The result of the only reported randomized controlled trial on MOM hip resurfacing arthroplasty could not be included in this assessment, because it used a cemented acetabular component, whereas in the new generation of implants, a cementless acetabular component is used. After omitting this publication, only case series remained. Summary of Findings   Health Outcomes The Harris hip score and SF-12 are 2 measures commonly used to report health outcomes in MOM hip resurfacing arthroplasty studies. Other scales used are the Oxford hip score and the University of California Los Angeles hip score. The case series showed that the mean revision rate of MOM hip resurfacing arthroplasty is 1.5% and the incidence of femoral neck fracture is 0.67%. Across all studies, 2 cases of osteonecrosis were reported. Four studies reported improvement in Harris hip scores. However, only 1 study reported a statistically significant improvement. Three studies reported improvement in SF-12 scores, of which 2 reported a significant improvement. One study reported significant improvement in UCLA hip score. Two studies reported postoperative Oxford hip scores, but no preoperative values were reported. None of the reviewed studies r

2006-01-01

9

Catastrophic failure of a metal-on-metal total hip arthroplasty secondary to metal inlay dissociation.  

PubMed

Metal-on-metal bearing surfaces in total hip arthroplasty have been recently shown to have acceptable survivorship properties (J Bone Joint Surg Am. 2006;88:1183; J Bone Joint Surg Am. 2006;88:1173), and they have certain advantages and disadvantages when compared to conventional metal-on-polyethylene bearing surfaces. Like traditional metal-on-polyethylene bearings, these metal-on-metal implants may also suffer from catastrophic failure. This case report represents an unusual situation in a 57-year-old man in which dissociation of a metal inlay in a metal-on-metal total hip arthroplasty resulted in articulation of the inferior aspect of the inlay with the femoral neck, leading to femoral neck notching, extensive periprosthetic soft tissue metallosis, osteolysis, and subsequent prosthetic catastrophic failure. PMID:20875944

Alaia, Michael J; Dayan, Alan J

2011-09-01

10

Mechanical failure of metal-polyethylene sandwich liner in metal-on-metal total hip replacement.  

PubMed

Metal-on-metal had been proposed as an optimal articulation in THRs, however, many monoblock prostheses have been recalled in the USA because of significant high rates of early failure. Metal-on-metal prostheses had been implanted in our institution, and this is a case history of a single patient, in whom metal-on-metal THRs with different femoral sizes of heads were implanted. A 57-year-old female patient underwent bilateral total hip replacements with metal-on-metal prostheses using metal-polyethylene "sandwich" liners 9 years ago on the right side and 7 years ago on the left side respectively. The only difference in both sides was the femoral head diameter of 28 mm in right and 34 mm in left. Seven years after the left surgery, the acetabular liner was dissociated, however, metallosis was not detected. Although the larger femoral head was thought to increase hip joint stability, it dictated a reduction in polyethylene thickness in this prosthesis design, and it was 4 mm in the left hip. Recently, metal-on-metal articulations are thought not to be optimal for hip joint bearing surface, however, this clinical failure was due to the polyethylene thickness and quality. PMID:25601670

Oshima, Yasushi; Fetto, Joseph F

2015-01-01

11

Friction in metal-on-metal total disc arthroplasty: effect of ball radius.  

PubMed

Total disc arthroplasty (TDA) can be used to replace a degenerated intervertebral disc in the spine. There are different designs of prosthetic discs, but one of the most common is a ball-and-socket combination. Contact between the bearing surfaces can result in high frictional torque, which can then result in wear and implant loosening. This study was designed to determine the effects of ball radius on friction. Generic models of metal-on-metal TDA were manufactured with ball radii of 10, 12, 14 and 16 mm, with a radial clearance of 0.015 mm. A simulator was used to test each sample in flexion-extension, lateral bending and axial rotation at frequencies of 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75 and 2 Hz under loads of 50, 600, 1200 and 2000 N, in new born calf serum. Frictional torque was measured and Stribeck curves were plotted to illustrate the lubrication regime in each case. It was observed that implants with a smaller ball radius showed lower friction and showed boundary and mixed lubrication regimes, whereas implants with larger ball radius showed boundary lubrication only. This study suggests designing metal-on-metal TDAs with ball radius of 10 or 12 mm, in order to reduce wear and implant loosening. PMID:22177670

Moghadas, Parshia; Mahomed, Aziza; Hukins, David W L; Shepherd, Duncan E T

2012-02-01

12

Metal on metal total hip arthroplasty and a large groin mass: Not always adverse reaction to metallic debris  

PubMed Central

Due to their improved wear rates, Metal-on-metal bearings have been increasingly used in the past decade by orthopaedic surgeons carrying out total hip arthroplasty. However there is increasing evidence that there are significant complications associated with such implants. One well documented complication is that of metallic debris leading to pseudotumour formation, however there is less known about associations with other tumours within the pelvis. We present two cases where an intra-pelvic mass in patients with metal-on-metal implants were diagnosed as being of a different aetiology. This highlights the need for careful assessment of such patients in order to guide appropriate management. PMID:25560054

Krishnan, Harry; Magnussen, Alex; Sharma, Aadhar; Skinner, John

2014-01-01

13

Metallic debris from metal-on-metal total hip arthroplasty regulates periprosthetic tissues.  

PubMed

The era of metal-on-metal (MoM) total hip arthroplasty has left the orthopaedic community with valuable insights and lessons on periprosthetic tissue reactions to metallic debris. Various terms have been used to describe the tissue reactions. Sometimes the nomenclature can be confusing. We present a review of the concepts introduced by Willert and Semlitsch in 1977, along with further developments made in the understanding of periprosthetic tissue reactions to metallic debris. We propose that periprosthetic tissue reactions be thought of as (1) gross (metallosis, necrosis, cyst formation and pseudotumour); (2) histological (macrophage-dominated, lymphocyte-dominated or mixed); and (3) molecular (expression of inflammatory mediators and cytokines such as interleukin-6 and tumor necrosis factor-alpha). Taper corrosion and modularity are discussed, along with future research directions to elucidate the antigen-presenting pathways and material-specific biomarkers which may allow early detection and intervention in a patient with adverse periprosthetic tissue reactions to metal wear debris. PMID:25405095

Lohmann, Christoph H; Singh, Gurpal; Willert, Hans-Georg; Buchhorn, Gottfried H

2014-11-18

14

Metallic debris from metal-on-metal total hip arthroplasty regulates periprosthetic tissues  

PubMed Central

The era of metal-on-metal (MoM) total hip arthroplasty has left the orthopaedic community with valuable insights and lessons on periprosthetic tissue reactions to metallic debris. Various terms have been used to describe the tissue reactions. Sometimes the nomenclature can be confusing. We present a review of the concepts introduced by Willert and Semlitsch in 1977, along with further developments made in the understanding of periprosthetic tissue reactions to metallic debris. We propose that periprosthetic tissue reactions be thought of as (1) gross (metallosis, necrosis, cyst formation and pseudotumour); (2) histological (macrophage-dominated, lymphocyte-dominated or mixed); and (3) molecular (expression of inflammatory mediators and cytokines such as interleukin-6 and tumor necrosis factor-alpha). Taper corrosion and modularity are discussed, along with future research directions to elucidate the antigen-presenting pathways and material-specific biomarkers which may allow early detection and intervention in a patient with adverse periprosthetic tissue reactions to metal wear debris. PMID:25405095

Lohmann, Christoph H; Singh, Gurpal; Willert, Hans-Georg; Buchhorn, Gottfried H

2014-01-01

15

2008 John Charnley Award: Metal Ion Levels After Metal-on-Metal Total Hip Arthroplasty: A Randomized Trial  

PubMed Central

Metal-on-metal bearing total hip arthroplasty is performed more commonly than in the past. There may be manufacturing differences such as clearance, roughness, metallurgy, and head size that affect performance. In a prospective, randomized trial, we compared 2-year postoperative ion levels for a 28-mm metal-on-polyethylene bearing with 28-mm and 36-mm metal-on-metal bearings. We measured serum, erythrocyte, and urine ion levels. We observed no difference in the ion levels for the 28-mm and 36-mm metal-on-metal bearings. The ion levels in these patients were lower than reported for most other metal-on-metal bearings. Although both erythrocyte and serum cobalt increased, erythrocyte chromium and erythrocyte titanium did not increase despite a four- to sixfold serum chromium and a three- to fourfold serum titanium increase. This may represent a threshold level for serum chromium and serum titanium below which erythrocytes are not affected. Level of Evidence: Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18855089

Engh, C. Anderson; MacDonald, Steven J.; Thompson, Abigail; Naudie, Douglas; Engh, Charles A.

2008-01-01

16

Metallosis, psoas abscess and infected hip prosthesis in a patient with bilateral metal on metal total hip replacement.  

PubMed

Metal on metal hip (MoM) resurfacing / replacement has recently been one of the most discussed topics in orthopaedics. Significant revision rates and complications are associated with MoM. We report a patient presenting with infection of a total hip prosthesis in conjunction with a psoas abscess in which the presentation is complicated by radiological evidence of suspected metallic debris in the lower limb tissues and elevated chromium and cobalt levels, suggestive of metallosis secondary to MoM. PMID:24960139

Rymaruk, S; Razak, A; McGivney, R

2012-01-01

17

Cutaneous manifestation of metallosis in a metal-on-metal total hip arthroplasty after acetabular liner dissociation.  

PubMed

In this case report, we describe a cutaneous manifestation of extensive metallosis in a patient 4 months post-metal-on-metal total hip arthroplasty with a Pinnacle cup with dissociation of the liner from the shell and resultant stripe burnishing of the shell and notch wear of the femoral neck. Dissociation of a metal liner has not been previously reported with this implant. Cutaneous metallosis has only been reported once in the literature. Clinicians should heighten their suspicion for metallosis secondary to hardware failure when encountering patients with skin discoloration in the setting of a painful and poorly functioning hip arthroplasty. In patients with failure of a metal-on-metal prosthesis with a modular metal liner in the acetabular component, liner dissociation must be considered. PMID:22397858

Sporer, Scott M; Chalmers, Peter N

2012-09-01

18

Gender is a significant factor for failure of metal-on-metal total hip arthroplasty.  

PubMed

Metal-on-metal (MoM) articulations offers low wear, larger head size, and increased stability. Reports of early failure are troubling and include failure of ingrowth and metal articulation problems such as metallosis, hypersensitivity, pseudotumor, and unexplained pain. This study investigates the survivorship of modern MoM articulations by gender. We reviewed 1589 primary MoM THA in 1363 patients, with minimum 2-year follow-up for 1212 hips. Follow-up averaged 60 months. There were 643 female patients and 719 male patients. The incidence of cup revision was significantly higher in women than in men (8.2% vs 2.7%; P = .0000), as was incidence of aseptic loosening (4.3% vs 1.1%; P = .0006), and failure for metal-bearing complications (2.2% vs 0.6%; P = .0126). There appear to be gender factors influencing the success of MoM THA, which may include hormonal, anatomic, or functional differences. PMID:21641761

Latteier, Michael J; Berend, Keith R; Lombardi, Adolph V; Ajluni, Andrew F; Seng, Brian E; Adams, Joanne B

2011-09-01

19

Metal ion levels in maternal and placental blood after metal-on-metal total hip arthroplasty.  

PubMed

There is concern regarding elevated metal ion levels in the blood during pregnancy and the potential fetal effects in women with metal-on-metal (MOM) implants. We obtained maternal and umbilical cord blood samples from 3 patients with a MOM hip arthroplasty and 7 control subjects without any metallic implants. Serum metal ion levels including chromium, cobalt, titanium, and nickel were tested using high-resolution sector-field inductively-coupled plasma-mass spectrometry. Mothers with MOM-bearing implants had significantly elevated levels of serum cobalt and chromium compared with control-group mothers, and umbilical cord blood from mothers with MOM implants also had significantly higher serum metal ion levels compared with control-group mothers. The results of this study show that circulating serum levels of metal ion degradation products from MOM bearings cross the placenta and expose the fetus to metal ions. However, the placenta exerts a modulatory effect on cord blood, resulting in decreased levels compared with maternal samples (approximately 15% of maternal chromium and 50% of maternal cobalt). Physicians and women of child-bearing age should be aware of this potential effect when considering the use of MOM-bearing implants. PMID:25490017

Novak, Clifford C; Hsu, Andrew R; Della Valle, Craig J; Skipor, Anastasia K; Campbell, Patricia; Amstutz, Harlan C; Jiranek, William A; Onyike, Aham; Pombar, Xavier F; Jacobs, Joshua J

2014-12-01

20

Histologic, serologic, and tribologic findings in failed metal-on-metal total hip arthroplasty: AAOS exhibit selection.  

PubMed

Despite multiple changes in second-generation metal-on-metal hip implants, greater-than-expected revision rates have led to alarm. We hypothesized that the finding of intraoperative metallosis would be associated with a high metal load on histologic analysis and that both would be associated with increased wear, greater serum metal ion levels, and predictable biologic responses in the histologic sections. We evaluated the implant positioning, serum ion levels, intraoperative findings of metallosis, wear characteristics of retrieved implants (tribology), histology, and outcomes in a series of eighteen large-diameter metal-on-metal total hip arthroplasties. The arthroplasties were divided into two groups on the basis of the intraoperative finding of metallosis and into two groups on the basis of the metal load score. Intraoperative metallosis was not associated with a high metal load score (p = 0.15). The finding of intraoperative metallosis was associated with greater serum metal ion levels, greater wear rates, and greater complication rates. Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) scores were similar between the metallosis and non-metallosis groups (p = 0.49) as well as between the high and low-metal-load groups (p = 0.56). PMID:24196475

Pelt, Christopher E; Erickson, Jill; Clarke, Ian; Donaldson, Thomas; Layfield, Lester; Peters, Christopher L

2013-11-01

21

Metal-on-metal bearings in cementless primary total hip arthroplasty  

Microsoft Academic Search

One hundred cementless titanium primary total hip arthroplasties with 28 mm Metasul bearings were prospectively studied (osteoarthritis in 76% of hips, mean age 59.6 years). Ninety-eight were reviewed after a 6-year average follow-up (range, 17–126 months) with clinical results graded excellent and good in 97%. One femoral component was revised for aseptic loosening at 7.8 years. Postoperative cobalt level was

Christian P. Delaunay

2004-01-01

22

Acetabular bone density and metal ions after metal-on-metal versus metal-on-polyethylene total hip arthroplasty; short-term results.  

PubMed

Information on periprosthetic acetabular bone density is lacking for metal-on-metal total hip arthroplasties. These bearings use cobalt-chromium instead of titanium acetabular components, which could lead to stress shielding and hence periprosthetic bone loss. Cobalt and chromium ions have detrimental effects on bone. It is unknown whether serum metal ion levels affect bone density clinically. We compared cementless large femoral head (mean 48 mm) metal-on-metal total hip arthroplasties (M2a-Magnum, Biomet) to cementless 28 mm metal-on-polyethylene total hip arthroplasties (Mallory-Head, Biomet) in a randomised clinical trial. We evaluated periprosthetic acetabular bone density and serum metal ion levels at 1 year postoperatively. Acetabular bone density was analyzed with dual energy x-ray absorptiometry in four horizontal regions of interest in 70 patients. After one year, acetabular bone density decreased (-3.5% to -7.8%) in three of four regions of interest in metal-on-polyethylene patients, but was retained in metal-on-metal patients. Bone density preservation was most pronounced superior to the metal-on-metal cup (+1% versus -3.7%). Serum cobalt, chromium and titanium ion levels were not related to bone density, nor to acetabular inclination or femoral head size. Oxford and Harris hip scores were similar in both groups. Contrary to our hypothesis, acetabular bone density was retained with metal-on-metal total hip arthroplasty, compared to metal-on-polyethylene arthroplasty. Bone preservation was most pronounced in the area superior to the cup. This could be a benefit during future revision surgery. PMID:24186673

Zijlstra, Wierd P; van der Veen, Hugo C; van den Akker-Scheek, Inge; Zee, Mark J M; Bulstra, Sjoerd K; van Raay, Jos J A M

2014-01-01

23

Comparison of synovial fluid, urine, and serum ion levels in metal-on-metal total hip arthroplasty at a minimum follow-up of 18 years.  

PubMed

Diagnosis of adverse reactions to metal debris in metal-on-metal hip arthroplasty is a multifactorial process. Systemic ion levels are just one factor in the evaluation and should not be relied upon solely to determine the need for revision surgery. Furthermore, the correlation between cobalt or chromium serum, urine, or synovial fluid levels and adverse local tissue reactions is still incompletely understood. The hypothesis was that elevated serum and urine metal-ion concentrations are associated with elevated local metal-ion concentrations in primary total hip arthroplasties (THA) and with failure of metal-on-metal articulations in the long-term. In our present study, we evaluated these concentrations in 105 cementless THA with metal-on-metal articulating surfaces with small head diameter at a minimum of 18 years postoperatively. Spearman correlation showed a high correlation between the joint fluid aspirate concentration of cobalt and chromium with the serum cobalt (r = 0.81) and chromium level (r = 0.77) in patients with the THA as the only source of metal-ions. In these patients serum metal-ion analysis is a valuable method for screening. In patients with more than one source of metal or renal insufficiency additional investigations, like joint aspirations are an important tool for evaluation of wear and adverse tissue reactions in metal-on-metal THA. PMID:24841922

Lass, Richard; Grübl, Alexander; Kolb, Alexander; Stelzeneder, David; Pilger, Alexander; Kubista, Bernd; Giurea, Alexander; Windhager, Reinhard

2014-09-01

24

Four-year study of cobalt and chromium blood levels in patients managed with two different metal-on-metal total hip replacements  

Microsoft Academic Search

Background: Metal-on-metal total hip prostheses will produce a certain amount of wear debris. This results in increased whole-blood metal levels, which may cause adverse effects. It is not known to what extent the problem has been overcome by advances in alloy technology.Methods: In 259 patients who with total hip replacement, blood cobalt and chromium concentrations were measured with atomic absorption

Christian Lhotka; Thomas Szekeres; Ilse Steffan; Klaus Zhuber; Karl Zweymüller

2003-01-01

25

Can we trust studies published by authors with financial conflicts? Using the decline of metal-on-metal total hip arthroplasty to investigate.  

PubMed

The objective of our study was to determine if authors with conflicts of interest are less likely to report negative study outcomes in metal-on-metal total hip arthroplasty. We performed a systematic review of 3 major orthopedic journals for articles related to metal-on-metal total hip arthroplasty over 12 years. A total of 64 studies reported clinical outcomes and were included. Reviewers assigned a positive, neutral, or negative label. Each study was noted for the presence of absence of a financial conflict. There was a significant trend from positive to negative study outcomes over time (P = .015). A similar negative trend was seen in studies written by authors with financial disclosures (P = .021). Authors with financial conflicts have contributed to the increase in negative outcomes reported in the literature. PMID:22682042

Hsu, Jason E; Liu, Stephen Y; Lee, Gwo-Chin

2012-09-01

26

Long-term results of a contemporary metal-on-metal total hip arthroplasty: a 10-year follow-up study.  

PubMed

The goal of the study was to evaluate the long-term results of a metal-on-metal articulation. We evaluated the results and histologic findings in patients who had undergone revision. One hundred total hip arthroplasties with a Lubrimet metal-on-metal articulation (Smith and Nephew, Rotkreuz, Switzerland) were implanted in 99 consecutive unselected patients in 1995 and 1996, and the results were prospectively analyzed up to a mean of 126 months postoperatively. Periprosthetic tissues of all 6 hips that had undergone revision because of aseptic loosening, mechanical failure, or periprosthetic fracture showed metallosis and extensive lymphocytic and plasma cell infiltration around the metal debris. With removal of the component because of aseptic loosening as the end point, survivorship was 98% for the stem and 96% for the cup. PMID:19596544

Neumann, Daniel R P; Thaler, Christoph; Hitzl, Wolfgang; Huber, Monika; Hofstädter, Thomas; Dorn, Ulrich

2010-08-01

27

Similar range of motion and function after resurfacing large–head or standard total hip arthroplasty  

PubMed Central

Background and purpose Large–size hip articulations may improve range of motion (ROM) and function compared to a 28–mm THA, and the low risk of dislocation allows the patients more activity postoperatively. On the other hand, the greater extent of surgery for resurfacing hip arthroplasty (RHA) could impair rehabilitation. We investigated the effect of head size and surgical procedure on postoperative rehabilitation in a randomized clinical trial (RCT). Methods We followed randomized groups of RHAs, large–head THAs and standard THAs at 2 months, 6 months, 1 and 2 years postoperatively, recording clinical rehabilitation parameters. Results Large articulations increased the mean total range of motion by 13° during the first 6 postoperative months. The increase was not statistically significant and was transient. The 2–year total ROM (SD) for RHA, standard THA, and large–head THA was 221° (35), 232° (36), and 225° (30) respectively, but the differences were not statistically significant. The 3 groups were similar regarding Harris hip score, UCLA activity score, step rate, and sick leave. Interpretation Head size had no influence on range of motion. The lack of restriction allowed for large articulations did not improve the clinical and patient–perceived outcomes. The more extensive surgical procedure of RHA did not impair the rehabilitation. This project is registered at ClinicalTrials.gov under # NCT01113762. PMID:23530872

2013-01-01

28

Predictive role of the lambda ratio in the evaluation of metal-on-metal total hip replacement.  

PubMed

The wear of metal-on-metal bearings is affected by various design parameters, such as the clearance or surface roughness. It would be very useful to have a significant indicator of wear according to these design parameters, such as the lambda ratio. Three different batches of cast high- and low-carbon cobalt-chromium hip implants (28 mm, 32 mm, and 36 mm diameters) were tested in a hip joint simulator for 2 x 10(6) cycles. Bovine calf serum was used as lubricant, and the samples were weighed at regular intervals during the test. The predictive role of the lambda ratio on the wear behaviour was investigated. Three different configurations were tested to explore the wear rate for a broad range of lambda ratios. The results of these studies clearly showed that the femoral heads of 36 mm diameter had the best wear behaviour with respect to the other two smaller configurations tested. From a predictive point of view, the lambda ratios associated with the configurations tested could clearly indicate that the femoral heads of 36 mm diameter worked in the mixed-lubrication regime (lambda > 1); all the smallest configurations (28mm size) had lambda < 1, thus showing their aptitude to work in the boundary lubrication regime, with substantially higher volume depletion due to wear. The lambda values associated with the 32 mm size varied in a range around 1 (0.95 < lambda < 1.16), suggesting the possibility of operating in the mixed-lubrication regime. PMID:18756681

Affatato, S; Spinelli, M; Zavalloni, M; Leardini, W; Viceconti, M

2008-07-01

29

Evaluation of the wear properties of a metal-on-metal total joint replacement system and in vitro macrophage response to resultant wear particles  

NASA Astrophysics Data System (ADS)

The wear of the polyethylene in total joint prostheses has been a source of morbidity and early device failure which has been extensively reported in the last ten to twelve years. While research continues to attempt to reduce the wear of polyethylene joint bearing surfaces by modifications in polymer processing, there is a renewed interest in the use of metal-on-metal bearing couples for hip replacement devices. This study investigated the in vitro wear resistance of two cobalt/chromium/molybdenum alloys, which differed primarily in the carbon content, as potential alloys for use in such a metal-on-metal hip bearing couple. The results showed that the alloy with the higher (0.25%) carbon content was more wear resistant and this alloy was chosen for testing in a hip simulator system which modeled the loads and motions which might be exerted on a clinically implanted hip replacement. Comparison of the results of metal-on-polyethylene specimens to metal-on-metal specimens showed that the volumetric wear of the metal-on-polyethylene bearing couple over 5,000,000 cycles was 110--180 times as great as that for the metal bearing couple. Polyethylene and metal particles retrieved from either pin-on-disk testing lubricant or hip simulator testing lubricant were cleaned and examined for consistency with the particles reported by other laboratories for particles from periprosthetic tissues and found to be similar. The particles were then added to macrophage (J774a) cell cultures and the release of Prostaglandin E2, Interleukin-6, and Tumor Necrosis Factor alpha measured for each experiment in response to the particles. The cell mediators released by the cells was found to correlate with the dosage of particles and the chemical identity of the particles. Most of the cellular response to the polyethylene particles seemed to be as a result of phagocytosis of the particles while most of the response to metal particles seemed to be related to cytotoxicity of the particles. Based upon the results of this study, metal-on-metal hip prostheses prepared from the high carbon cobalt/chromium alloy (CCM+) that was investigated seem to hold sufficient promise to justify human clinical trials.

St. John, Kenneth Raymond

30

Metal ion levels decrease after revision for metallosis arising from large-diameter metal-on-metal hip arthroplasty.  

PubMed

Concerns have been renewed regarding the possible long-term effects of elevated circulating levels of cobalt and chromium as a direct result of implantation of large femoral head diameter metal-on-metal bearings. In order to establish whether metal ion levels remain persistently elevated, we compared metal ion levels before and after revision surgery in patients with large head diameter (greater than 38 mm) metal-on-metal total hip arthroplasty or hip resurfacing arthroplasty. At greater than one year post removal of a large-diameter metal-on-metal hip implant for the indication of symptomatic metallosis, metal ion levels were found to fall to almost normal levels. PMID:22308623

Ebreo, Darren; Khan, Abdul; El-Meligy, Mohammed; Armstrong, Catherine; Peter, Viju

2011-12-01

31

Local tissue reaction and necrosis-induced femoral nerve palsy in a patient with a metal-on-metal total hip arthroplasty: a case report.  

PubMed

This case report describes a 54-year-old Hispanic male who developed femoral nerve palsy approximately 1 year after metal-on-metal total hip arthroplasty (MOM THA). Cobalt and chromium levels were 4.8 ppb and undetectable, respectively. MRI demonstrated a well-encapsulated pseudotumor that communicated with the anterior portion of the right hip, and EMG showed neuropraxic femoral nerve injury. As a result, the patient experienced motor and sensory loss in the femoral and proximal saphenous nerve distributions. Surgical revision to ceramic-on-poly THA with debridement and decompression of the pseudotumor improved the patient's neurological status. Similar acute local tissue reactions have been described but the serum levels of cobalt and chrome associated with these reactions have been variable. Wear particles and products produced from corrosion at the head taper junction from MOM THA can potentially lead to cellular dysfunction with subsequent pseudotumer formation, but these reactions and fluid collections have also been found. In this patient, serum cobalt levels were elevated, while serum chromium levels remained undetectable. The purpose of this case report is to describe one patient's response and to review the recent literature regarding potential complications of MOM THA. PMID:24941401

Wodowski, Andrew J; Rider, Carson M; Mihalko, William M

2014-01-01

32

The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements  

PubMed Central

Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods. PMID:22904606

Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, André

2012-01-01

33

Adverse reaction to metal debris after ReCap-M2A-Magnum large-diameter-head metal-on-metal total hip arthroplasty  

PubMed Central

Background and purpose The clinical findings of adverse reaction to metal debris (ARMD) following large-diameter-head metal-on-metal total hip arthroplasty (LDH MoM THA) may include periarticular fluid collections, soft tissue masses, and gluteal muscle necrosis. The ReCap-M2a-Magnum LDH MoM THA was the most commonly used hip device at our institution from 2005 to 2012. We assessed the prevalence of and risk factors for ARMD with this device. Methods 74 patients (80 hips) had a ReCap-M2a-Magnum LDH MoM THA during the period August 2005 to December 2006. These patients were studied with hip MRI, serum chromium and cobalt ion measurements, the Oxford hip score questionnaire, and by clinical examination. The prevalence of ARMD was recorded and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.0 (5.5–6.7) years. Results A revision operation due to ARMD was needed by 3 of 74 patients (3 of 80 hips). 8 additional patients (8 hips) had definite ARMD, but revision was not performed. 29 patients (32 hips) were considered to have a probable or possible ARMD. Altogether, 43 of 80 hips had a definite, probable, or possible ARMD and 34 patients (37 hips) were considered not to have ARMD. In 46 of 78 hips, MRI revealed a soft tissue mass or a collection of fluid (of any size). The symptoms clicking in the hip, local hip swelling, and a feeling of subluxation were associated with ARMD. Interpretation ARMD is common after ReCap-M2a-Magnum total hip arthroplasty, and we discourage the use of this device. Asymptomatic patients with a small fluid collection on MRI may not need instant revision surgery but must be followed up closely. PMID:24171688

2013-01-01

34

Effect of femoral head size on the wear of metal on metal bearings in total hip replacements under adverse edge-loading conditions  

PubMed Central

Abstract Metal-on-metal (MoM) bearings have shown low-wear rates under standard hip simulator conditions; however, retrieval studies have shown large variations in wear rates and mechanisms. High-wear in vivo has caused catastrophic complications and has been associated with steep cup-inclination angle (rotational malpositioning). However, increasing the cup-inclination angle in vitro has not replicated the increases in wear to the same extent as those observed in retrievals. Clinically relevant wear rates, patterns, and particles were observed in vitro for ceramic-on-ceramic bearings when microseparation (translational malpositioning) conditions were introduced into the gait cycle. In the present study, 28 and 36-mm MoM bearings were investigated under adverse conditions. Increasing the cup angle from 45° to 65° resulted in a significant increase in the wear rate of the 28 mm bearings. However, for the 36 mm bearings, head-rim contact did not occur under the steep cup-angle condition, and the wear rate did not increase. The introduction of microseparation to the gait cycle significantly increased the wear rate of the MoM bearings. Cup angle and head size did not influence the wear rate under microseparation conditions. This study indicated that high-in vivo wear rates were associated with edge loading due to rotational malpositioning such as high-cup-inclination angle and translational malpositioning that could occur due to several surgical factors. Translational malpositioning had a more dominant effect on the wear rate. Preclinical simulation testing should be undertaken with translational and rotational malpositioning conditions as well as standard walking cycle conditions defined by the ISO standard. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013. PMID:23281164

Al-Hajjar, Mazen; Fisher, John; Williams, Sophie; Tipper, Joanne L; Jennings, Louise M

2013-01-01

35

Metal-on-Metal Hip Retrieval Analysis: A Case Report  

PubMed Central

This is a case report involving a single case with severe bone and soft tissue destruction in a young male patient with a 10-year-metal on-metal total hip arthroplasty. Following complete aseptic erosion of the affected hip greater trochanter and abductor muscles, the hip was revised for recurrent instability. Histological examination of the patient's periprosthetic tissues, serological studies, and review of recent medical reports of similar cases were used to support an explanation of the destructive process and better contribute to our understanding of human reaction to metal debris in some patients following metal-on-metal hip arthroplasty. PMID:23840999

Pace, Thomas B.; Rusaw, Kara A.; Minette, Lawrence J.; Shirley, Brayton R.; Snider, Rebecca G.; DesJardins, John D.

2013-01-01

36

The minimal invasive direct anterior approach in combination with large heads in total hip arthroplasty - is dislocation still a major issue? a case control study  

PubMed Central

Background There have been increasing numbers of publications in recent years on minimally invasive surgery (MIS) for total hip arthroplasty (THA), reporting results with the use of different head sizes, tribologic and functional outcomes. This study presents the results and early complication rates after THA using the direct anterior approach (DAA) in combination with head sizes???36 mm. Methods A total of 113 patients with THA were included in the study. The Harris Hip Score (HHS) was determined, a radiographic evaluation was carried out, and complications were recorded. The minimum follow-up period was 2 years (means 35?±?7 months). Results The HHS improved from 43.6 (± 12) to 88.2 (± 14; P?large heads is associated with good to very good functional results in the majority of cases. The complication rates are not increased. The rate of dislocation mainly as an complication of the first two years can be markedly reduced in particular. PMID:24621189

2014-01-01

37

Metal-on-Metal Hip Resurfacing Arthroplasty  

PubMed Central

Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the teratogenicity of MOM implants in humans. Conclusions Metal-on-metal HRA can be beneficial for appropriately selected patients, provided the surgeon has the surgical skills required for performing this procedure. Plain Language Summary There are many young patients with hip diseases who need to have hip replacement surgery. Although a traditional hip replacement is an acceptable procedure for these patients, some surgeons prefer using a newer technique in young patients called hip resurfacing. In this technique, instead of removing the head of the femoral bone, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the hip socket, similar to the cups used in traditional hip replacement. The analysis of the revision rates (i.e., how soon and in how many patients the surgery needs to be redone) and safety of resurfacing implants showed that generally these implants can last 10 years or more for the majority of young people. Good outcomes can be expected when skilled surgeons perform the surgery in properly selected patients. However, since these implants are made of metal (cobalt and chromium alloy), there is concern about excess metal debris production due to friction between the 2 metal components leading to high levels of metal ions in the blood and urine of patients. The production of metal debris may result in inflammation in the joint or development of a benign soft tissue mass leading to implant failure. However, it has been shown that this risk can be reduced by proper positioning of the implant and the careful selection of patients for this procedure. Little is known about the long-term biological effects of high levels of metal ions in the blood and urine of patients who have received metal implants. There is concern about potential increases in the risk of cancer and the risk of fetal abnormalities, but these effects have not been established yet. However, since cobalt and chromium can pass the placental barrier, implants that are not metal-on-metal are recommended for women at childbearing ages if they

Sehatzadeh, S; Kaulback, K; Levin, L

2012-01-01

38

Edge loading in metal-on-metal hips: low clearance is a new risk factor  

PubMed Central

The revision rate of large head metal-on-metal and resurfacing hips are significantly higher than conventional total hip replacements. The revision of these components has been linked to high wear caused by edge loading; which occurs when the head–cup contact patch extends over the cup rim. There are two current explanations for this; first, there is loss of entrainment of synovial fluid resulting in breakdown of the lubricating film and second, edge loading results in a large local increase in contact pressure and consequent film thickness reduction at the cup rim, which causes an increase in wear. This paper develops a method to calculate the distance between the joint reaction force vector and the cup rim – the contact patch centre to rim (CPCR) distance. However, the critical distance for the risk of edge loading is the distance from the contact patch edge to rim (CPER) distance. An analysis of explanted hip components, divided into edge worn and non-edge-worn components showed that there was no statistical difference in CPCR values, but the CPER value was significantly lower for edge worn hips. Low clearance hips, which have a more conformal contact, have a larger diameter contact patch and thus are more at risk of edge loading for similarly positioned hips. PMID:22558836

Zografos, Angelos; Sayles, Ritchie S; Hart, Alister; Cann, Philippa

2012-01-01

39

THA Using Metal-on-Metal Articulation in Active Patients Younger Than 50 Years  

Microsoft Academic Search

The main concern of patients with longer life expectancies and of patients who are younger and more active is the longevity\\u000a of their total hip arthroplasty. We retrospectively reviewed 83 cementless total hip arthroplasties in 73 patients implanted\\u000a with metal-on-metal articulation. All patients were younger than 50 years old (average age, 41 years) at the time of the index\\u000a procedure, and 80%

Christian P. Delaunay; François Bonnomet; Philippe Clavert; Philippe Laffargue; Henri Migaud

2008-01-01

40

Graphitic Tribological Layers in Metal-on-Metal Hip Replacements  

NASA Astrophysics Data System (ADS)

Arthritis is a leading cause of disability, and when nonoperative methods have failed, a prosthetic implant is a cost-effective and clinically successful treatment. Metal-on-metal replacements are an attractive implant technology, a lower-wear alternative to metal-on-polyethylene devices. Relatively little is known about how sliding occurs in these implants, except that proteins play a critical role and that there is a tribological layer on the metal surface. We report evidence for graphitic material in the tribological layer in metal-on-metal hip replacements retrieved from patients. As graphite is a solid lubricant, its presence helps to explain why these components exhibit low wear and suggests methods of improving their performance; simultaneously, this raises the issue of the physiological effects of graphitic wear debris.

Liao, Y.; Pourzal, R.; Wimmer, M. A.; Jacobs, J. J.; Fischer, A.; Marks, L. D.

2011-12-01

41

Graphitic tribological layers in metal-on-metal hip replacements.  

PubMed

Arthritis is a leading cause of disability, and when nonoperative methods have failed, a prosthetic implant is a cost-effective and clinically successful treatment. Metal-on-metal replacements are an attractive implant technology, a lower-wear alternative to metal-on-polyethylene devices. Relatively little is known about how sliding occurs in these implants, except that proteins play a critical role and that there is a tribological layer on the metal surface. We report evidence for graphitic material in the tribological layer in metal-on-metal hip replacements retrieved from patients. As graphite is a solid lubricant, its presence helps to explain why these components exhibit low wear and suggests methods of improving their performance; simultaneously, this raises the issue of the physiological effects of graphitic wear debris. PMID:22194573

Liao, Y; Pourzal, R; Wimmer, M A; Jacobs, J J; Fischer, A; Marks, L D

2011-12-23

42

CoCrMo Metal-on-Metal Hip Replacements  

PubMed Central

After the rapid growth in the use of CoCrMo metal-on-metal hip replacements since the second generation was introduced circa 1990, metal-on-metal hip replacements have experienced a sharp decline in the last two years due to biocompatibility issues related to wear and corrosion products. Despite some excellent clinical results, the release of wear and corrosion debris and the adverse response of local tissues have been of great concern. There are many unknowns regarding how CoCrMo metal bearings interact with the human body. This perspective article is intended to outline some recent progresses in understanding wear and corrosion of metal-on-metal hip replacement both in-vivo and in-vitro. The materials, mechanical deformation, corrosion, wear-assisted corrosion, and wear products will be discussed. Possible adverse health effects caused by wear products will be briefly addressed, as well as some of the many open questions such as the detailed chemistry of corrosion, tribochemical reactions and the formation of graphitic layers. Nowadays we design almost routinely for high performance materials and lubricants for automobiles; humans are at least as important. It is worth remembering that a hip implant is often the difference between walking and leading a relatively normal life, and a wheelchair. PMID:23196425

Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence

2012-01-01

43

Information for Patients Who Have Metal-on-Metal Hip Implants  

MedlinePLUS

... Medical Devices Products and Medical Procedures Implants and Prosthetics Metal-on-Metal Hip Implants Section Contents Menu Products and Medical Procedures Implants and Prosthetics Metal-on-Metal Hip Implants The Hip Joint ...

44

Metal-on-metal joint bearings and hematopoetic malignancy  

PubMed Central

Abstract This is a review of the hip arthroplasty era. We concentrate on new metal bearings, surface replacements, and the lessons not learned, and we highlight recent reports on malignancies and joint implants. A low incidence of blood malignancies has been found in bone marrow taken at prosthetic surgery. The incidence is increased after replacement with knee implants that release very low systemic levels of metal ions. A carcinogenic effect of the high levels of metal ions released by large metal-on-metal implants cannot be excluded. Ongoing Swedish implant registry studies going back to 1975 can serve as a basis for evaluation of this risk. PMID:23140092

2012-01-01

45

Investigation on stick phenomena in metal-on-metal hip joints after resting periods.  

PubMed

Insufficient understanding of tribological behaviour in total joint arthroplasty is considered as one of the reasons for prosthesis failure. Contrary to the continuous motion input profiles of hip simulators, human locomotion contains motion interruptions. These occurring resting periods can cause stick phenomena in metal-on-metal hip joints. The aim of the present study was to investigate the tribological sensitivity of all-metal bearings to motion interruptions on in vitro test specimens and retrieved implants. Friction and wear with and without resting periods were quantified. Unlike the metal-on-polyethylene joints, the static friction of metal-on-metal joints increased up to micros = 0.3 with rest, while wear appeared to be unaffected. This effect is caused by the interlocking of firmly adhered carbon layers, which were generated from the protein-containing lubricant through tribochemical reactions. Since more than 80 per cent of the retrieved implants exhibited macroscopically visible carbon layers, the increase in friction presumably also occurs under physiological conditions, which is then transferred to the bone-implant interface. These recurrent tangential stress peaks should be considered for the design features of the cup-bone interface, in particular when larger-sized implant heads are used. PMID:16669389

Wimmer, M A; Nassutt, R; Sprecher, C; Loos, J; Täger, G; Fischer, A

2006-02-01

46

Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing – Systematic Review of Clinical and Epidemiological Studies  

PubMed Central

Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip resurfacing arthroplasty. Patients with implanted MoM-bearing should receive regular and standardized monitoring of metal ion concentrations. Further research is indicated especially with regard to potential systemic reactions due to accumulation of metal products. PMID:23950923

Hartmann, Albrecht; Hannemann, Franziska; Lützner, Jörg; Seidler, Andreas; Drexler, Hans; Günther, Klaus-Peter; Schmitt, Jochen

2013-01-01

47

[Cobalt poisoning due to metal-on-metal hip implants].  

PubMed

Since 2011, cobalt and chromium blood levels are measured in patients with a metal-on-metal hip implant (MoM prosthesis). In this article we discuss the health risks that are related to chronically elevated blood cobalt concentrations induced by abnormal wear and corrosion of the MoM prosthesis. Only a few patients who have systemic symptoms of poisoning, besides local symptoms around the failing MoM prosthesis, have been described in the literature. Toxic blood cobalt concentrations may be accompanied by hypothyroidism, polyneuropathy, impairment of cranial nerves II and VIII and cardiomyopathy. Treatment consists of removal of the prosthesis. In patients with a normal kidney function, the cobalt blood levels rapidly decrease and symptoms of cobalt intoxication subside. Chelation therapy should be restricted to those patients who are unable to undergo removal of the prosthesis immediately due to their medical condition. This can for example be because of a severe cobalt-induced cardiomyopathy. PMID:23075776

Dijkman, Marieke A; de Vries, Irma; Mulder-Spijkerboer, Henneke; Meulenbelt, Jan

2012-01-01

48

Larger diameter bearings reduce wear in metal-on-metal hip implants.  

PubMed

Metal-on-metal hip arthroplasty has the longest clinical history of all total arthroplasties. We asked whether large diameter femoral heads would result in less wear than those with small diameters. We also asked if there is a threshold diameter that ensures good wear behavior. We tested three batches of cast high-carbon cobalt-chromium-molybdenum hip implants (28 mm, 36 mm, and 54 mm diameters) in a hip simulator for 5 million cycles. We used bovine serum as lubricant and weighed the samples at regular intervals during testing. The 28-mm configuration had almost twice the wear of the 54-mm configuration, but we observed no difference between the 36-mm and the 54-mm configurations. The similarity in the wear performances of the larger configurations supports the presence of a threshold diameter that ensures good wear behavior. PMID:17065844

Affatato, S; Leardini, W; Jedenmalm, A; Ruggeri, O; Toni, A

2007-03-01

49

Wear of surface engineered metal-on-metal hip prostheses.  

PubMed

The wear of existing metal-on-metal (MOM) hip prostheses (1 mm3/million cycles) is much lower than the more widely used polyethylene-on-metal bearings (30-100 mm3/million cycles). However, there remain some potential concerns about the toxicity of metal wear particles and elevated metal ion levels, both locally and systemically in the human body. The aim of this study was to investigate the wear, wear debris and ion release of fully coated surface engineered MOM bearings for hip prostheses. Using a physiological anatomical hip joint simulator, five different bearing systems involving three thick (8-12 microm) coatings, TiN, CrN and CrCN, and one thin (2 microm) coating diamond like carbon (DLC) were evaluated and compared to a clinically used MOM cobalt chrome alloy bearing couple. The overall wear rates of the surface engineered prostheses were at least 18-fold lower than the traditional MOM prostheses after 2 million cycles and 36-fold lower after 5 million cycles. Consequently, the volume of wear debris and the ion levels in the lubricants were substantially lower. These parameters were also much lower than in half coated (femoral heads only) systems that have been reported previously. The extremely low volume of wear debris and concentration of metal ions released by these surface engineered systems, especially with CrN and CrCN coatings, have considerable potential for the clinical application of this technology. PMID:15334994

Fisher, J; Hu, X Q; Stewart, T D; Williams, S; Tipper, J L; Ingham, E; Stone, M H; Davies, C; Hatto, P; Bolton, J; Riley, M; Hardaker, C; Isaac, G H; Berry, G

2004-03-01

50

[Release of metals from metal-on-metal hip prostheses].  

PubMed

The present study examined blood and urinary concentrations of Cr and Co in 30 patients with metal-on-metal hip prostheses without signs of wear and 6 patients with prosthetic bearing and clear signs of wear and metallosis. The determination in biological fluids showed in patients with not signs of wear the geometric mean concentration of metals only modestly increased (CoS 0.5 microg/l, CoU 5.7 microg/l, CrS 0.8 microg/l, CrU 3.4 microg/l) compared to the reference values, while the wear caused a significant increase in the concentration of both Co (CoS 94.6 microg/l, CoU 334.5 microg/l) and Cr (CrS 57.7 microg/l, CrU 89.4 microg/I). As the results, the not functioning implants are a risks to the patients and are associated with high levels of metals in biological fluids. Currently, the patients with metallosis had not signs and symptoms associated with metal toxicity, but high concentrations could to cause kidney, peripheral nervous system, heart, and thyroid damage. PMID:23393850

Nicolli, A; Chiara, F; Bortoletti, I; Pasqualato, F; Mongillo, M; Gambalunga, A; Biggi, F; Trevisan, A

2011-01-01

51

Microseparation, fluid pressure and flow in failures of metal-on-metal hip resurfacing arthroplasties  

PubMed Central

Objectives Metal-on-metal (MoM) hip resurfacing was introduced into clinical practice because it was perceived to be a better alternative to conventional total hip replacement for young and active patients. However, an increasing number of reports of complications have arisen focusing on design and orientation of the components, the generation of metallic wear particles and serum levels of metallic ions. The procedure introduced a combination of two elements: large-dimension components and hard abrasive particles of metal wear. The objective of our study was to investigate the theory that microseparation of the articular surfaces draws in a high volume of bursal fluid and its contents into the articulation, and at relocation under load would generate high pressures of fluid ejection, resulting in an abrasive water jet. Methods This theoretical concept using MoM resurfacing components (head diameter 55 mm) was modelled mathematically and confirmed experimentally using a material-testing machine that pushed the head into the cup at a rate of 1000 mm/min until fully engaged. Results The mathematical model showed the pattern but not the force of fluid ejection, the highest pressures were expected when the separation of the components was only a fraction of one millimetre. The experimental work confirmed the results; with the mean peak ejection pressure of 43 763 N/m2 equivalent to 306 mmHg or 5 psi. Conclusions The mechanical effect of the high-pressure abrasive water jet is the likely cause of the spectrum of complications reported with metal-on-metal resurfacing. Investigating serum levels of metallic elements may not be the best method for assessing the local mechanical effects of the abrasive water jet. PMID:23610667

Wroblewski, B. M.; Siney, P. D.; Fleming, P. A.

2012-01-01

52

On the inflammatory response in metal-on-metal implants  

PubMed Central

Background Metal-on-metal implants are a special form of hip endoprostheses that despite many advantages can entail serious complications due to release of wear particles from the implanted material. Metal wear particles presumably activate local host defence mechanisms, which causes a persistent inflammatory response with destruction of bone followed by a loosening of the implant. To better characterize this inflammatory response and to link inflammation to bone degradation, the local generation of proinflammatory and osteoclast-inducing cytokines was analysed, as was systemic T cell activation. Methods By quantitative RT-PCR, gene expression of cytokines and markers for T lymphocytes, monocytes/macrophages and osteoclasts, respectively, was analysed in tissue samples obtained intraoperatively during exchange surgery of the loosened implant. Peripheral T cells were characterized by cytofluorometry before surgery and 7 to 10 days thereafter. Results At sites of osteolysis, gene expression of cathepsin K, CD14 and CD3 was seen, indicating the generation of osteoclasts, and the presence of monocytes and of T cells, respectively. Also cytokines were highly expressed, including CXCL8, IL-1ß, CXCL2, MRP-14 and CXCL-10. The latter suggest T cell activation, a notion that could be confirmed by detecting a small, though conspicuous population of activated CD4+ cells in the peripheral blood T cells prior to surgery. Conclusion Our data support the concept that metallosis is the result of a local inflammatory response, which according to histomorphology and the composition of the cellular infiltrate classifies as an acute phase of a chronic inflammatory disease. The proinflammatory environment, particularly the generation of the osteoclast-inducing cytokines CXCL8 and IL1-ß, promotes bone resorption. Loss of bone results in implant loosening, which then causes the major symptoms of metallosis, pain and reduced range of motion. PMID:24650243

2014-01-01

53

Assessing the material loss of the modular taper interface in retrieved metal-on-metal hip replacements  

NASA Astrophysics Data System (ADS)

Measuring the amount of material loss in the case of revised hip replacements is considered to be a prerequisite of understanding and assessing the true in vivo performance of the implant. This paper outlines a method developed by the authors for quantifying taper material loss as well as more general taper interface parameters. Previous studies have mostly relied on visual inspection to assess the material loss at the taper interface, whereas this method aims to characterize any surface and form changes through the use of an out-of-roundness measurement machine. Along with assessing the volumetric wear, maximum linear penetration and taper contact length can also be determined. The method was applied to retrieved large head metal-on-metal femoral heads in order to quantify the material loss at this junction. Material loss from the female femoral head taper can be characterized as a localized area that is in contact with the stem taper surface. The study showed that this method has good repeatability and a low level of interoperability variation between operators.

Bills, Paul J.; Racasan, R.; Tessier, P.; Blunt, L. A.

2015-06-01

54

The treatment of femoral neuropathy due to pseudotumour caused by metal-on-metal resurfacing arthroplasty.  

PubMed

Concerns now exist about the long-term biological effects of exposure to orthopaedic metal alloys, particularly serum cobalt and chromium ions derived from metal-on-metal wear debris in these patients. A pseudotumour mass complicating metal-on-metal resurfacing arthroplasty has been recognized by orthopaedic oncologists and specialist hip units. Pseudotumours may also present with a major nerve palsy. Two cases of femoral neuropathy due to pseudotumour masses caused by metal-on-metal resurfacing arthroplasty are presented. Preoperative neurophysiological studies showed severe and irreversible pathological changes to nerve function with neurohistopathological evidence of complete nerve destruction with a previously unreported pathological appearance. This may represent a previously unrecognized pathological process, possibly 'toxic' in nature, resulting from metal-on-metal wear debris. Prolonged follow-up and detailed clinical assessment of patients after hip resurfacing arthroplasty is advocated with planned and expeditious revision of any patient in whom evidence of femoral neuropathy develops. PMID:19097010

Harvie, P; Giele, H; Fang, C; Ansorge, O; Ostlere, S; Gibbons, M; Whitwell, D

2008-01-01

55

Tribolayer Formation in a Metal-on-Metal (MoM) Hip Joint: An Electrochemical Investigation  

PubMed Central

The demand for total hip replacement (THR) surgery is increasing in the younger population due to faster rehabilitation and more complete restoration of function. Up to 2009, metal-on-metal (MoM) hip joint bearings were a popular choice due to their design flexibility, post-operative stability and relatively low wear rates. The main wear mechanisms that occur along the bearing surface of MoM joints are tribochemical reactions that deposit a mixture of wear debris, metal ions and organic matrix of decomposed proteins known as a tribolayer. No in-depth electrochemical studies have been reported on the structure and characteristics of this tribolayer or about the parameters involved in its formation. In this study, we conducted an electrochemical investigation of different surfaces (bulk-like: control, nano-crystalline: new implant and tribolayer surface: retrieved implant) made out of two commonly used hip CoCrMo alloys (high-carbon and low-carbon). As per ASTM standard, cyclic polarization tests and electrochemical impedance spectroscopy tests were conducted. The results obtained from electrochemical parameters for different surfaces clearly indicated a reduction in corrosion for the tribolayer surface (Icorr: 0.76 ?A/cm2). Further, polarization resistance (Rp:2.39±0.60M?/cm2) and capacitance (Cdl:15.20±0.75 ?F/cm2) indicated variation in corrosion kinetics for the tribolayer surface, that attributed to its structure and stability in a simulated body environment. PMID:24099949

Mathew, MT; Nagelli, C; Pourzal, R; Fischer, A; Laurent, MP; Jacobs, JJ; Wimmer, MA

2013-01-01

56

Does Ion Release Differ Between Hip Resurfacing and Metal-on-metal THA?  

PubMed Central

Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potential increased metal ion release. We hypothesized there were no differences in serum concentrations of chromium, cobalt, and molybdenum between patients who had metal-on-metal hip resurfacing (Group A; average head diameter, 48 mm; median followup, 24 months) and patients who had 28-mm metal-on-metal THA (Group B; median followup, 25 months). Serum concentrations also were compared with concentrations in healthy subjects. We identified no differences in ion levels between Groups A and B. A distinction was made according to gender. Women showed a higher chromium release in Group A whereas men had a higher cobalt release in Group B. Values obtained from Group A were higher than those of the control subjects. Our data suggest metal-on-metal bearings for THA should not be rejected because of concern regarding potential increased metal ion release; however, patients with elevated ion levels, even without loosening or toxicity, could be at higher risk and should be followed up periodically. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18196364

Moroni, Antonio; Cadossi, Matteo; Baldini, Nicola; Giannini, Sandro

2008-01-01

57

Asymptomatic pseudotumours after metal-on-metal hip resurfacing show little change within one year.  

PubMed

The aim of this study was to establish the natural course of unrevised asymptomatic pseudotumours after metal-on-metal (MoM) hip resurfacing during a six- to 12-month follow-up period. We used repeated metal artefact reduction sequence (MARS)-magnetic resonance imaging (MRI), serum metal ion analysis and clinical examination to study 14 unrevised hips (mean patient age 52.7 years, 46 to 68, 5 female, 7 male) with a pseudotumour and 23 hips (mean patient age 52.8 years, 38 to 69, 7 female, 16 male) without a pseudotumour. The mean post-operative time to the first MARS-MRI scan was 4.3 years (2.2 to 8.3), and mean time between the first and second MARS-MRI scan was eight months (6 to 12). At the second MRI scan, the grade of severity of the pseudotumour had not changed in 35 hips. One new pseudotumour (Anderson C2 score, moderate) was observed, and one pseudotumour was downgraded from C2 (moderate) to C1 (mild). In general, the characteristics of the pseudotumours hardly changed. Repeated MARS-MRI scans within one year in patients with asymptomatic pseudotumours after MoM hip resurfacing showed little or no variation. In 23 patients without pseudotumour, one new asymptomatic pseudotumour was detected. This is the first longitudinal study on the natural history of pseudotumours using MARS-MRI scans in hip resurfacing, and mirrors recent results for 28 mm diameter MoM total hip replacement. PMID:24293591

van der Weegen, W; Brakel, K; Horn, R J; Hoekstra, H J; Sijbesma, T; Pilot, P; Nelissen, R G H H

2013-12-01

58

Comparison of ceramic-on-metal and metal-on-metal hip prostheses under adverse conditions.  

PubMed

Ceramic-on-metal (COM) hip replacements, where the head is BIOLOX® Delta ceramic and the liner is CoCrMo alloy, have demonstrated reduced wear under standard simulator conditions compared to metal-on-metal (MOM) bearings. COM hips are now being used clinically around the world. MOM hip resurfacings have raised concerns regarding poor clinical performance and increased in vivo wear was associated with steeply inclined acetabular components and translationally malpositioned components. The aim of this study was to compare the wear rates of MOM and COM total hip prostheses under adverse edge-loading conditions in a hip simulator test. COM and MOM 36 mm hip prostheses were tested in a hip simulator, with liners mounted to provide a clinical inclination angle of 55°. A simplified gait cycle and microseparation conditions were applied for two million cycles in 25% new born calf serum. The overall mean volumetric wear rate of COM bearings under adverse conditions was 0.36 ± 0.55 mmł/million cycles; this was significantly less than MOM wear (1.32 ± 0.91 mmł/million cycles). Under these adverse conditions; the contact zone on the head intersects the rim of the cup causing substantially elevated contact stresses, disrupting the protective boundary and mixed lubrication regime causing changes in types and severity of wear mechanisms. In COM bearings, the harder head does not become damaged when there is lubricant starvation and wear does not accelerate. In conclusion, COM bearings showed reduced wear compared to MOM bearings under standard and adverse clinically relevant simulator conditions and COM bearings may provide an advantage over MOM bearings under edge-loading conditions clinically. PMID:23359608

Williams, Sophie; Al-Hajjar, Mazen; Isaac, Graham H; Fisher, John

2013-07-01

59

New Insights into Wear and Biological Effects of Metal-on-Metal Bearings  

PubMed Central

Background: Despite the renewed interest in metal-on-metal implants in the past two decades, the underlying wear mechanisms and biological effects are still not fully understood. Methods: This paper first reviews the tribology of metal-on-metal bearings, bringing new insights into the interaction of wear and corrosion, and putting the characteristics and the potential origin of wear particles in perspective with the proposed wear mechanisms. It then summarizes the current knowledge on the biological effects of particles and metal ions in relation to these wear mechanisms. Results: Tribochemical reactions play an important role in the wear of metal-on-metal joints. The generated tribomaterial, which progressively forms by mechanical mixing of the uppermost nanocrystalline zone of the metal surface with proteins from the synovial fluid, governs the wear rate and influences the corrosive behavior of the bearing. Nanometer-sized wear particles may initially originate from the passivation layer covering the implant surface and then detach from this tribolayer. The inflammatory response observed surrounding metal-on-metal implants appears to be lower than that around metal-on-polyethylene implants. However, metallic byproducts, which can complex with proteins, may lead to a T lymphocyte-mediated hypersensitivity response. Conclusions: The tribolayer appears to have beneficial effects on the wear rate. Much information has been gained on wear particle characteristics, but the exact mechanisms of particle detachment remain to be further elucidated. Excessive wear along with a hypersensitivity response may be at the origin of the early adverse tissue reactions that have been recently reported in some patients with metal-on-metal implants. Clinical Relevance: Future development of new methods to improve the tribolayer retention and optimize the tribocorrosive properties of the implant may minimize the clinical impact of implant wear and immune responses. PMID:21543694

Catelas, Isabelle; Wimmer, Markus A.

2011-01-01

60

Metallosis-induced iliopsoas bursal cyst causing venous obstruction and lower-limb swelling after metal-on-metal THA.  

PubMed

The formation of iliopsoas bursal cystic lesions after total hip arthroplasty is an infrequently reported condition. This article describes an unusual complication of a current-generation metal-on-metal total hip arthroplasty.A woman presented with unilateral spontaneous lower-limb swelling that developed 5 years postoperatively. It occurred secondary to venous obstruction by a metallosis-induced iliopsoas bursal cyst associated with markedly elevated intralesional cobalt and chromium levels. Metal artifact reduction sequence magnetic resonance imaging showed that the bursal cyst was communicating with the hip joint and that it severely compressed the common femoral vein. Based on the findings of high local tissue metal ions and vertical cup positioning causing edge loading, the authors proposed an inflammatory reaction to metal debris that tracked into the iliopsoas bursa and formed a cyst. The patient underwent revision of the excessively vertical acetabular component and conversion to a ceramic-on-ceramic bearing interface, drainage of the bursal cyst, and synovectomy. No signs existed of local recurrence at 1-year follow-up.To the authors' knowledge, the occurrence of metallosis-induced iliopsoas bursitis with secondary pressure effects after contemporary metal-on-metal total hip arthroplasty has not been reported. When treating hip dysplasia, one must avoid maximizing cup-host bone contact at the risk of oververticalization. Iliopsoas bursal cystic lesions can lead to severe vascular compressive symptoms with no ominous radiographic findings. Physicians and orthopedic surgeons should be aware of the possibility of this complication in patients with unexplained unilateral lower-limb swelling. PMID:23218642

Algarni, Abdulrahman D; Huk, Olga L; Pelmus, Manuela

2012-12-01

61

Metal-on-Metal Hip Prostheses and Systemic Health: A Cross-Sectional Association Study 8 Years after Implantation  

PubMed Central

There is public concern over the long term systemic health effects of metal released from hip replacement prostheses that use large-diameter metal-on-metal bearings. However, to date there has been no systematic study to determine which organs may be at risk, or the magnitude of any effect. We undertook a detailed cross-sectional health screen at a mean of 8 years after surgery in 35 asymptomatic patients who had previously received a metal-on-metal hip resurfacing (MoMHR) versus 35 individually age and sex matched asymptomatic patients who had received a conventional hip replacement. Total body bone mineral density was 5% higher (mean difference 0.05 g/cm2, P?=?0.02) and bone turnover was 14% lower (TRAP 5b, mean difference ?0.56IU/L, P?=?0.006; osteocalcin, mean difference ?3.08 ng/mL, P?=?0.03) in the hip resurfacing versus conventional hip replacement group. Cardiac ejection fraction was 7% lower (mean absolute difference ?5%, P?=?0.04) and left ventricular end-diastolic diameter was 6% larger (mean difference 2.7 mm, P?=?0.007) in the hip resurfacing group versus those patients who received a conventional hip replacement. The urinary fractional excretion of metal was low (cobalt 5%, chromium 1.5%) in patients with MoMHR, but creatinine clearance was normal. Diuretic prescription was associated with a 40% increase in the fractional excretion of chromium (mean difference 0.5%, P?=?0.03). There was no evidence of difference in neuropsychological, renal tubular, hepatic or endocrine function between groups (P>0.05). Our findings of differences in bone and cardiac function between patient groups suggest that chronic exposure to low elevated metal concentrations in patients with well-functioning MoMHR prostheses may have systemic effects. Long-term epidemiological studies in patients with well-functioning metal on metal hip prostheses should include musculoskeletal and cardiac endpoints to quantitate the risk of clinical disease. PMID:23762480

Prentice, Jennifer R.; Clark, Matthew J.; Hoggard, Nigel; Morton, Allison C.; Tooth, Claire; Paley, Martyn N.; Stockley, Ian; Hadjivassiliou, Marios; Wilkinson, J. Mark

2013-01-01

62

Revision of metal-on-metal hip arthroplasty in a tertiary center  

PubMed Central

Background and purpose Operative findings during revision of metal-on-metal hip arthroplasty (MOMHA) vary widely and can involve massive soft tissue and bone disruption. As a result, planning of theater time and resources is difficult, surgery is challenging, and outcomes are often poor. We describe our experience with revision of MOMHA and provide recommendations for management. Patients and methods We present the findings and outcomes of 39 consecutive MOMHAs (in 35 patients) revised in a tertiary unit (median follow-up time 30 (12–54) months). The patients underwent a preoperative work-up including CT, metal artifact reduction sequence (MARS) MRI, and blood metal ion levels. Results We determined 5 categories of failure. 8 of 39 hips had conventional failure mechanisms including infection and impingement. Of the other 31 hips, 14 showed synovitis without significant disruption of soft tissue; 6 had a cystic pseudotumor with significant soft tissue disruption; 7 had significant osteolysis; and 4 had a solid pseudotumor. Each category of failure had specific surgical hazards that could be addressed preoperatively. There were 2 reoperations and 1 patient (2 hips) died of an unrelated cause. Median Oxford hip score (OHS) was 37 (9–48); median change (?OHS) was 17 (–10 to 41) points. ?OHS was similar in all groups—except those patients with solid pseudotumors and those revised to metal-on-metal bearings, who fared worse. Interpretation Planning in revision MOMHA is aided by knowledge of the different categories of failure to enable choice of appropriate personnel, theater time, and equipment. With this knowledge, satisfactory outcomes can be achieved in revision of metal-on-metal hip arthroplasty. PMID:23621810

2013-01-01

63

Ion release in stable hip arthroplasties using metal-on-metal articulating surfaces: a comparison between short- and medium-term results.  

PubMed

The use of metallic heads articulating with metallic cups could solve the problem of polyethylene (PE) wear in total hip replacement (THR) with metal-on-PE bearings. A conspicuous release of metal ions from new models of metal-on-metal bearings has been found in the short-term, but it is yet unclear whether the medium-term corrosion rate is high or, on the contrary, it becomes negligible, because of the continuous surface finishing. Our purpose was to compare the serum ion values (nanograms per milliliter) in 15 patients with metal-on-metal stable prosthesis (Group A), in the short-term (subgroup A(1); mean follow-up: 24 mo) and medium-term (subgroup A(2); mean follow-up: 52 mo), in order to determine whether the ion release decreased with time of implant. Chromium (Cr), cobalt (Co), molybdenum (Mo) and aluminum (Al) were analyzed. Twenty-two presurgical patients were used for comparison (Group B). The reference range was obtained from a population of 27 healthy subjects (Group C). Co and Cr levels in the medium-term (subgroup A(2)) were not decreased in comparison with the short-term values (subgroup A(1)) and were significantly higher (p < 0.001) than presurgical and reference values. Otherwise, Mo and Al concentrations were not significantly increased in comparison with reference values. In conclusion, despite the apparent advantage of metal-on-metal coupling, especially in younger patient populations, there is a major concern about the extent and duration of the relevant "internal" exposure to Cr and Co ions. This exposure should be carefully monitored, in order to clarify the biologic effects of ion dissemination and, consequently, to identify risks concerning long-term toxicity of metals. PMID:12918026

Savarino, L; Granchi, D; Ciapetti, G; Cenni, E; Greco, M; Rotini, R; Veronesi, C A; Baldini, N; Giunti, A

2003-09-01

64

Surface engineering: a low wearing solution for metal-on-metal hip surface replacements.  

PubMed

Increased patient blood and serum levels of Co and Cr and dissemination of metal wear particles throughout organs and tissues are the primary concerns with metal-on-metal surface replacements. Surface engineering, providing a ceramic bearing surface on a metal substrate, could provide a solution. This study investigated thick (>10 microm) arc evaporation plasma vapor deposition chromium nitride (CrN) coated surface replacements in terms of wear, ion levels, and wear particles in a 10 million cycle hip simulator study, compared to a contemporary metal-on-metal surface replacement. The ion levels were measured by inductively coupled plasma mass spectroscopy. The wear particles were imaged by field emission gun scanning electron microscopy. The CrN-coated bearings had 80% lower wear than the MoM controls. The Cr and Co ion levels in the lubricant of the CrN bearings were 73 and 98% lower than in the MoM controls. The wear particles produced were in the nanometer size range and round to oval in morphology. The CrN coating could provide a reduction in the wear and ion release of MoM surface replacements, thereby reducing the perceived risks to the patient associated with these prostheses. PMID:19195030

Leslie, Ian J; Williams, Sophie; Brown, Chris; Anderson, James; Isaac, Graham; Hatto, Peter; Ingham, Eileen; Fisher, John

2009-08-01

65

Effects of CoCr metal wear debris generated from metal-on-metal hip implants and Co ions on human monocyte-like U937 cells.  

PubMed

Hip resurfacing with cobalt-chromium (CoCr) alloy was developed as a surgical alternative to total hip replacement. However, the biological effects of nanoparticles generated by wear at the metal-on-metal articulating surfaces has limited the success of such implants. The aim of this study was to investigate the effects of the combined exposure to CoCr nanoparticles and cobalt ions released from a resurfacing implant on monocytes (U937 cells) and whether these resulted in morphology changes, proliferation alterations, toxicity and cytokine release. The interaction between prior exposure to Co ions and the cellular response to nanoparticulate debris was determined to simulate the situation in patients with metal-on-metal implants receiving a second implant. Effects on U937 cells were mainly seen after 120h of treatment. Prior exposure to Co ions increased the toxic effects induced by the debris, and by Co ions themselves, suggesting the potential for interaction in vivo. Increased TNF-? secretion by resting cells exposed to nanoparticles could contribute to osteolysis processes in vivo, while increased IFN-? production by activated cells could represent cellular protection against tissue damage. Data suggest that interactions between Co ions and CoCr nanoparticles would occur in vivo, and could threaten the survival of a CoCr metal implant. PMID:25433333

Posada, Olga M; Tate, Rothwelle J; Grant, M Helen

2015-03-01

66

Effect of ion implantation on the tribology of metal-on-metal hip prostheses.  

PubMed

Nitrogen ion implantation (which considerably hardens the surface of the bearing) may represent one possible method of reducing the wear of metal-on-metal (MOM) hip bearings. Currently there are no ion-implanted MOM bearings used clinically. Therefore a physiological hip simulator test was undertaken using standard test conditions, and the results compared to previous studies using the same methods. N2-ion implantation of high carbon cast Co-Cr-Mo-on-Co-Cr-Mo hip prostheses increased wear by 2-fold during the aggressive running-in phase compared to untreated bearing surfaces, plus showing no wear reductions during steady-state conditions. Although 2 specimens were considered in the current study, it would appear that ion implantation has no clinical benefit for MOM. PMID:15578563

Bowsher, John G; Hussain, Azad; Williams, Paul; Nevelos, Jim; Shelton, Julia C

2004-12-01

67

Metal-on-metal hip surface replacement: the routine use is not justified.  

PubMed

Metal-on-metal resurfacing of the hip (MoMHR) has enjoyed a resurgence in the last decade, but is now again in question as a routine option for osteoarthritis of the hip. Proponents of hip resurfacing suggest that its survival is superior to that of conventional hip replacement (THR), and that hip resurfacing is less invasive, is easier to revise than THR, and provides superior functional outcomes. Our argument serves to illustrate that none of these proposed advantages have been realised and new and unanticipated serious complications, such as pseudotumors, have been associated with the procedure. As such, we feel that the routine use of MoMHR is not justified. PMID:25381402

Dunbar, M J; Prasad, V; Weerts, B; Richardson, G

2014-11-01

68

A lexicon for wear of metal-on-metal hip prostheses.  

PubMed

Research on metal-on-metal (MoM) hip bearings has generated an extensive vocabulary to describe the wear processes and resultant surface damage. However, a lack of consistency and some redundancy exist in the current terminology. To facilitate the understanding of MoM tribology and to enhance communication of results among researchers and clinicians, we propose four categories of wear terminology: wear modes refer to the in vivo conditions under which the wear occurred; wear mechanisms refer to fundamental wear processes (adhesion, abrasion, fatigue, and tribochemical reactions); wear damage refers to the resultant changes in the morphology and/or composition of the surfaces; and wear features refer to the specific wear phenomena that are described in terms of the relevant modes, mechanisms, and damage. Clarifying examples are presented, but it is expected that terms will be added to the lexicon as new mechanisms and types of damage are identified. Corrosion refers to electrochemical processes that can remove or add material and thus also generate damage. Corrosion can act alone or may interact with mechanical wear. Examples of corrosion damage are also presented. However, an in-depth discussion of the many types of corrosion and their effects is beyond the scope of the present wear lexicon. PMID:24844814

McKellop, Harry A; Hart, Alister; Park, Sang-Hyun; Hothi, Harry; Campbell, Pat; Skinner, John A

2014-09-01

69

Wear of metal-on-metal hip bearings: metallurgical considerations after hip simulator studies.  

PubMed

Metal-on-metal hip-bearing components with different percentages of carbon content (low and high carbon) were tested in 6 different configurations using a hip joint simulator. The aim of this study was to characterize metallurgical and tribological events occurring at the articulating surfaces of these articulations. Also, ion release was evaluated and correlated with wear. After the test, for the high-carbon components, carbides were observed below the matrix surface. In the low-carbon content components, most carbides were "carbide-free", while a minority were worn below the matrix surface with increased test cycles. In the cast alloy components, some carbides were pulled out resulting in micropits. Scanning microscope electron characterization of the tested specimens showed scratches and holes. The surface showed a dominant severe wear mechanism due to third-body particles. A greater amount of ions was released in the lubricant used during the wear test for the smaller diameter compared with the bigger one. This study showed that the metallurgical and tribological events taking place at the articulating surfaces of metal-metal hip implants are numerous and complex. The surface morphology after the test showed the effect of more critical working conditions with smaller diameters. PMID:22198601

Affatato, Saverio; Traina, Francesco; Ruggeri, Oddone; Toni, Aldo

2011-12-01

70

Influence of stem type on material loss at the metal-on-metal pinnacle taper junction.  

PubMed

The clinical importance of material loss at the head-stem junction is unknown. Comparison of retrievals with different stem types can provide the opportunity to understand the importance of the taper junction. This was a case-control study involving 20 retrieved 36 mm metal-on-metal Pinnacle (DePuy) hips that were paired with either a Corail (n = 10) or S-ROM (n = 10) stem. The median head taper material loss rate for the Corail group was 0.238 (0.0002-2.178) mm(3)/year and was significantly greater than the S-ROM group (p = 0.042), which had a median material loss rate of 0.132 (0.015-0.518) mm(3)/year. The only significant difference between the groups was the stem taper roughness and length: this was rougher and shorter for the Corails. Long and smooth stem taper designs are preferred when used in conjunction with metal heads. PMID:25655958

Hothi, Harry S; Whittaker, Robert K; Meswania, Jay M; Blunn, Gordon W; Skinner, John A; Hart, Alister J

2015-01-01

71

Wear mechanisms in metal-on-metal bearings: the importance of tribochemical reaction layers.  

PubMed

Metal-on-metal (MoM) bearings are at the forefront in hip resurfacing arthroplasty. Because of their good wear characteristics and design flexibility, MoM bearings are gaining wider acceptance with market share reaching nearly 10% worldwide. However, concerns remain regarding potential detrimental effects of metal particulates and ion release. Growing evidence is emerging that the local cell response is related to the amount of debris generated by these bearing couples. Thus, an urgent clinical need exists to delineate the mechanisms of debris generation to further reduce wear and its adverse effects. In this study, we investigated the microstructural and chemical composition of the tribochemical reaction layers forming at the contacting surfaces of metallic bearings during sliding motion. Using X-ray photoelectron spectroscopy and transmission electron microscopy with coupled energy dispersive X-ray and electron energy loss spectroscopy, we found that the tribolayers are nanocrystalline in structure, and that they incorporate organic material stemming from the synovial fluid. This process, which has been termed "mechanical mixing," changes the bearing surface of the uppermost 50 to 200 nm from pure metallic to an organic composite material. It hinders direct metal contact (thus preventing adhesion) and limits wear. This novel finding of a mechanically mixed zone of nanocrystalline metal and organic constituents provides the basis for understanding particle release and may help in identifying new strategies to reduce MoM wear. PMID:19877285

Wimmer, Markus A; Fischer, Alfons; Büscher, Robin; Pourzal, Robin; Sprecher, Christoph; Hauert, Roland; Jacobs, Joshua J

2010-04-01

72

What is a "normal" wear pattern for metal-on-metal hip bearings?  

PubMed

In addition to classical run-in and steady-state wear phases, metal-on-metal (MOM) hip bearings have encountered "runaway wear" (RAW) trends in simulator studies. This puzzling behavior has resulted in 2- to 19-fold wear increases compared with other apparently "identical" bearings. MOM bearings have shown five identifiable RAW wear patterns in joint simulators; therefore, additional descriptive terms were used here to indicate various observed patterns, for example, "breakaway wear" (BAW), which was defined as a higher wear trend that recovers to steady-state wear. As these trends commonly occur for MOM, this raises the question of what can be considered "normal" behavior or "abnormal"? In an effort to identify possible causes for this behavior, the current study investigated six Co-Cr bearings, which closely matched with respect to geometrical tolerances. Despite close control of design and test variables, BAW occurred in 30% of the MOM bearings, producing a threefold wear increase above otherwise identical MOM bearings within the same group. The majority of the BAW (85%) occurred on the cup side and was validated by growth of wear scars and concentrations of metal ions. One bearing that showed continuing BAW at 5 Mc revealed a cup that was 50% smoother than other cups whereas its mating head was 50% rougher, thus signifying that highly polished areas were sites of the highest MOM wear. The two BAW bearings with high wear showed the greatest conformity at 5 Mc, in apparent contradistinction to classical lubrication theory. PMID:19582850

Bowsher, J G; Clarke, I C; Williams, P A; Donaldson, T K

2009-10-01

73

Wear behaviour of cobalt-chromium-molybdenum alloys used in metal-on-metal hip implants  

NASA Astrophysics Data System (ADS)

The influence of carbon (C) content, microstructure, crystallography and mechanical properties on the wear behaviour of metal-on-metal (MM) hip implants made from commercially available cobalt-chromium-molybdenum (CoCrMo) alloys designated as American Society of Testing and Materials (ASTM) grade F1537, F75 and as-cast were studied in this work. The as-received bars of wrought CoCrMo alloys (ASTM F1537 of either about 0.05% or 0.26% C) were each subjected to various heat treatments to develop different microstructures. Pin and plate specimens were fabricated from each bar and were tested against each other using a linear reciprocating pin-on-plate apparatus in 25% by volume bovine serum solution. The applied normal load was 9.81 N and the reciprocating plate had a sinusoidal velocity with an average speed of 26 mm/s. The wear was measured gravimetrically and it was found to be most strongly affected by alloy C content, irrespective of grain size or carbide morphology. More precisely, the wear behaviour was directly correlated to the dissolved C content of the alloys. Increased C in solid-solution coincided with lower volumetric wear since C helps to stabilize the face-centred cubic (FCC) crystal structure thus limiting the amount of strain induced transformation (SIT) to the hexagonal close-packed crystal structure (HCP). Based on the observed surface twinning in and around the contact zone and the potentially detrimental effect of the HCP phase, it was postulated that the MM wear behaviour of CoCrMo alloys in the present study was controlled by a deformation mechanism, rather than corrosion or tribochemical reactions.

Varano, Rocco

74

Changes in blood ion levels after removal of metal-on-metal hip replacements  

PubMed Central

Background and purpose In patients with metal-on-metal (MoM) hip prostheses, pain and joint effusions may be associated with elevated blood levels of cobalt and chromium ions. Since little is known about the kinetics of metal ion clearance from the body and the rate of resolution of elevated blood ion levels, we examined the time course of cobalt and chromium ion levels after revision of MoM hip replacements. Patients and methods We included 16 patients (13 female) who underwent revision of a painful MoM hip (large diameter, modern bearing) without fracture or infection, and who had a minimum of 4 blood metal ion measurements over an average period of 6.1 (0–12) months after revision. Results Average blood ion concentrations at the time of revision were 22 ppb for chromium and 43 ppb for cobalt. The change in ion levels after revision surgery varied extensively between patients. In many cases, over the second and third months after revision surgery ion levels decreased to 50% of the values measured at revision. Decay of chromium levels occurred more slowly than decay of cobalt levels, with a 9% lag in return to normal levels. The rate of decay of both metals followed second-order (exponential) kinetics more closely than first-order (linear) kinetics. Interpretation The elimination of cobalt and chromium from the blood of patients who have undergone revision of painful MoM hip arthroplasties follows an exponential decay curve with a half-life of approximately 50 days. Elevated blood levels of cobalt and chromium ions can persist for at least 1 year after revision, especially in patients with high levels of exposure. PMID:24758321

Durrani, Salim K; Sampson, Barry; Panetta, Therese; Liddle, Alexander D; Sabah, Shiraz A; Chan, Newton K; Skinner, John A; Hart, Alister J

2014-01-01

75

Cross-sectional imaging of metal-on-metal hip arthroplasties  

PubMed Central

Background and purpose — Metal artifact reduction sequence (MARS) MRI is widely advocated for surveillance of metal-on-metal hip arthroplasties (MOM-HAs). However, its use is limited by susceptibility artifact at the prosthesis-bone interface, local availability, patient compliance, and cost (Hayter et al. 2011a). We wanted to determine whether CT is a suitable substitute for MARS MRI in evaluation of the painful MOM-HA. Patients and methods — 50 MOM-HA patients (30 female) with unexplained painful prostheses underwent MARS MRI and CT imaging. 2 observers who were blind regarding the clinical data objectively reported the following outcomes: soft tissue lesions (pseudotumors), muscle atrophy, and acetabular and femoral osteolysis. Diagnostic test characteristics were calculated. Results — Pseudotumor was diagnosed in 25 of 50 hips by MARS MRI and in 11 of 50 by CT. Pseudotumors were classified as type 1 (n = 2), type 2A (n = 17), type 2B (n = 4), and type 3 (n = 2) by MARS MRI. CT did not permit pseudotumor classification. The sensitivity of CT for diagnosis of pseudotumor was 44% (95% CI: 25–65). CT had “slight” agreement with MARS MRI for quantification of muscle atrophy (? = 0.23, CI: 0.16–0.29; p < 0.01). Osteolysis was identified in 15 of 50 patients by CT. 4 of these lesions were identified by MARS MRI. Interpretation — CT was found to be superior to MRI for detection of osteolysis adjacent to MOM-HA, and should be incorporated into diagnostic algorithms. CT was unable to classify and failed to detect many pseudotumors, and it was unreliable for assessment of muscle atrophy. Where MARS MRI is contraindicated or unavailable, CT would be an unsuitable substitute and other modalities such as ultrasound should be considered PMID:25267500

Robinson, Elizabeth; Henckel, Johann; Sabah, Shiraz; Satchithananda, Keshthra; Skinner, John; Hart, Alister

2014-01-01

76

Metal presence in hair after metal-on-metal resurfacing arthroplasty.  

PubMed

The elevation of metal levels in serum and urine during post-operative follow-up is a frequent find following the implantation of certain models of metal-on-metal hip prostheses. Among 45 patients with the same resurfacing prostheses, chromium (Cr) and cobalt (Co) levels in serum and urine were determined at 3, 4, 5, and 6 years after surgery. In the same period, levels of Cr, Co and molibdene (Mo) in scalp hair were also measured. Mean Cr and Co levels in serum were 8.29 µg/L (SD 17.97) and 8.38 µg/L (SD 21.97), respectively, whereas in urine levels were 16.20 µg/L (SD SD 32.55) and 75.40 µg/L (SD 190.86), respectively. In hair, mean Cr level were 163.27 µg/g (SD 300.62), mean Co level 61.98 µg/g (SD 126.48), and Mo 31.36 µg/g (SD 37.86). A high concordance was observed between chromium-urine and chromium-serum and between cobalt-urine and cobalt-hair. A moderate concordance was present between cobalt-urine and cobalt-serum, and between cobalt-hair and cobalt-serum. Eleven patients required revision surgery, five of them due to metallosis and periarticular cyst. At 1 year after reintervention, analytics were performed again and the following decrease rates were found: 42.8% in Cr levels, 51.1% in Mo levels, and 90.3% in Co levels. PMID:23893786

Rodríguez de la Flor, María; Hernández-Vaquero, Daniel; Fernández-Carreira, José Manuel

2013-12-01

77

The relationship between the presence of metallosis and massive infection in metal-on-metal hip replacements.  

PubMed

With the increased use of metal-on-metal as a bearing surface, complications and side effects are being recognised more frequently. We present a small series of a previously unreported complication, which appears specific to metal-on-metal bearing surface arthroplasties: three cases of infection in the presence of local metal debris and histological features of aseptic lymphocytic vasculitis associated lesions (ALVAL). Each case is associated with significant soft tissue loss and bone destruction to such an extent that pelvic discontinuity has occurred. We postulate that the combination of metal debris, ALVAL and tissue necrosis provides a unique environment for peri-prosthetic bacterial growth and rapid spread of infection. PMID:20544666

Donaldson, James R; Miles, Jonathan; Sri-Ram, Kesavan; Poullis, Christopher; Muirhead-Allwood, Sarah; Skinner, John

2010-01-01

78

Blood metal ion testing is an effective screening tool to identify poorly performing metal-on-metal bearing surfaces  

PubMed Central

Objectives The aims of this piece of work were to: 1) record the background concentrations of blood chromium (Cr) and cobalt (Co) concentrations in a large group of subjects; 2) to compare blood/serum Cr and Co concentrations with retrieved metal-on-metal (MoM) hip resurfacings; 3) to examine the distribution of Co and Cr in the serum and whole blood of patients with MoM hip arthroplasties; and 4) to further understand the partitioning of metal ions between the serum and whole blood fractions. Methods A total of 3042 blood samples donated to the local transfusion centre were analysed to record Co and Cr concentrations. Also, 91 hip resurfacing devices from patients who had given pre-revision blood/serum samples for metal ion analysis underwent volumetric wear assessment using a coordinate measuring machine. Linear regression analysis was carried out and receiver operating characteristic curves were constructed to assess the reliability of metal ions to identify abnormally wearing implants. The relationship between serum and whole blood concentrations of Cr and Co in 1048 patients was analysed using Bland-Altman charts. This relationship was further investigated in an in vitro study during which human blood was spiked with trivalent and hexavalent Cr, the serum then separated and the fractions analysed. Results Only one patient in the transfusion group was found to have a blood Co > 2 µg/l. Blood/Serum Cr and Co concentrations were reliable indicators of abnormal wear. Blood Co appeared to be the most useful clinical test, with a concentration of 4.5 µg/l showing sensitivity and specificity for the detection of abnormal wear of 94% and 95%, respectively. Generated metal ions tended to fill the serum compartment preferentially in vivo and this was replicated in the in vitro study when blood was spiked with trivalent Cr and bivalent Co. Conclusions Blood/serum metal ion concentrations are reliable indicators of abnormal wear processes. Important differences exist however between elements and the blood fraction under study. Future guidelines must take these differences into account. PMID:23836464

Sidaginamale, R. P.; Joyce, T. J.; Lord, J. K.; Jefferson, R.; Blain, P. G.; Nargol, A. V. F.; Langton, D. J.

2013-01-01

79

Mid-Term Results of Metal-on-Metal Hip Resurfacing for Treatment of Osteoarthritis Secondary to Developmental Dysplasia of the Hip: A Minimum of 8-Years of Follow-Up  

PubMed Central

Background Metal-on-metal resurfacing arthroplasty is an attractive alternative to conventional total hip arthroplasty in patients with osteoarthritis secondary to developmental dysplasia of the hip (DDH). The purpose of this study was to assess the mid-term clinical outcome and mid-term survivorship of Metal-on-metal resurfacing arthroplasty in patients suffering from osteoarthritis secondary to DDH. Material/Methods Between May 2003 and Dec. 2005, 15 operations using ASR™ and 19 using Corin were performed in 29 patients to treat advanced osteoarthritis secondary to DDHs. There were 6 males (20.7%) and 23 females (79.3%), with an average age of 47.2 years (range, 36–64 years). Clinical and radiographic results were observed. All patients were followed up at the 1st, 2nd, 3rd, 6th, and 12th months after surgery and annually thereafter. Results The overall survival was 88.2% at a minimum follow-up of 8 years, but the survival was 91.2% after excluding the infections as the cause of component loosening and failure. The mean Harris hip score improved from 48.27±3.13 (range, 14–71) to 89.63±3.42 (range, 65–100) at latest follow-up. The flexion was from 75.14±8.05° to 107.21±9.34. Only 4 failed because of deep infection, femoral neck fracture, and aseptic loosening. Conclusions Metal-on-metal resurfacing arthroplasty showed perfect results at a minimum of 8-years of follow-up in our study, and may be a reasonable option for osteoarthritis secondary to developmental dysplasia of the hip (DDH). PMID:25410054

Qu, Yuxing; Jiang, Tao; Zhao, Hong; Gao, Yi; Zheng, Chong; Xu, Jianda

2014-01-01

80

Is Increased Modularity Associated With Increased Fretting and Corrosion Damage in Metal-On-Metal Total Hip Arthroplasty Devices?  

PubMed Central

This retrieval study documents taper damage at modular interfaces in retrieved MOM THA systems and investigates if increased modularity is associated with increased fretting and corrosion. One hundred thirty-four (134) heads and 60 stems (41 modular necks) of 8 different bearing designs (5 manufacturers) were analyzed. Damage at the shell–liner interface of 18 modular CoCr acetabular liners and the corresponding 11 acetabular shells was also evaluated. The results of this study support the hypothesis that fretting and corrosion damage occurs at a variety of modular component interfaces in contemporary MOM THAs. We also found that modularity of the femoral stem was associated with increased damage at the head. An analysis of component and patient variables revealed that dissimilar alloy pairing, larger head sizes, increased medio-lateral offsets and longer neck moment arms were all associated with increased taper damage at the modular interfaces. PMID:23910820

Higgs, Genymphas B.; Hanzlik, Josa A.; MacDonald, Daniel W.; Gilbert, Jeremy L.; Rimnac, Clare M.; Kurtz, Steven M.

2014-01-01

81

A safe zone for acetabular component position in metal-on-metal hip resurfacing arthroplasty: winner of the 2012 HAP PAUL award.  

PubMed

A safe zone for acetabular component positioning in hip resurfacing (RAIL: Relative Acetabular Inclination Limit) was calculated based on implant size and acetabular inclination angle (AIA). For AIA below the RAIL, there were no adverse wear failures or dislocations, and only 1% of cases with ion levels above 10 ?g/L. Other than high inclination angle and small bearing size, female gender was the only other factor that correlated with high ion levels in the multivariate analysis. Seven hundred sixty-one hip resurfacing cases are included in this study. The UCLA activity score, femoral shaft angle, body mass index, weight, American Society of Anesthesiologists score, combined range of motion, diagnosis, age, gender, implant brand, AIA, bearing size, and duration of implantation were analyzed to determine the potential risk factors for elevated metal ion levels. These findings apply to sub hemispheric metal-on-metal bearings with similar coverage arcs as the Biomet and Corin hip resurfacing brands. Additional problems may occur when these bearings are connected with trunions on stems for total hip arthroplasty. PMID:23540536

Liu, Fei; Gross, Thomas P

2013-08-01

82

MRI findings following metal on metal hip arthroplasty and their relationship with metal ion levels and acetabular inclination angles.  

PubMed

Following the global recall of all ASR metal on metal hip products, our aim was to correlate MRI findings with acetabular inclination angles and metal ion levels in patients with these implants. Both cobalt and chromium levels were significantly higher in the presence of a periprosthetic fluid collection. There was no association between the presence of a periprosthetic mass, bone marrow oedema, trochanteric bursitis or greater levels of abductor muscle destruction for cobalt or chromium. There was no association between the level of periprosthetic tissue reaction and the acetabular inclination angle with any of the pathologies identified on MRI. The relationship between MRI pathology, metal ion levels and acetabular inclination angles in patients with ASR implants remains unclear adding to the complexity of managing patients. PMID:24793890

Fox, Ciara M; Bergin, Karen M; Kelly, Gabrielle E; McCoy, Gerry F; Ryan, Anthony G; Quinlan, John F

2014-08-01

83

Detection of cobalt in synovial fluid from metal-on-metal hip prosthesis: correlation with the ion haematic level.  

PubMed

Hip replacement with large metal-on-metal (MoM) coupling has recently been under attention for its metal ions release, inducing several disorders. Since the blood level toxicity threshold for cobalt is known, the aim of this work is to determine whether Co serum and blood levels correlate with the synovial fluid level. Beside this, the synovial fluid Co from patients without prosthesis has also been measured. Co has been determined in 54 samples (32 unilateral MoM and 22 controls) with inductively coupled plasma mass spectrometry in the three matrices. In the prosthesized group, cobalt was significantly higher compared with controls and in the synovial fluid it strongly correlated with whole blood Co (p?=?0.847) and serum (p?=?0.855). Moreover, the Co levels into whole blood and serum were significantly different. In conclusion, haematic Co concentration correctly reflects Co local level. PMID:24134776

Beraudi, Alina; Catalani, Simona; Montesi, Monica; Stea, Susanna; Sudanese, Alessandra; Apostoli, Pietro; Toni, Aldo

2013-12-01

84

A HIERARCHY OF COMPUTATIONALLY DERIVED SURGICAL AND PATIENT INFLUENCES ON METAL ON METAL PRESS-FIT ACETABULAR CUP FAILURE  

PubMed Central

The impact of anatomical variation and surgical error on excessive wear and loosening of the acetabular component of large diameter metal on metal hip arthroplasties was measured using a multi-factorial analysis through 112 different simulations. Each surgical scenario was subject to eight different daily loading activities using finite element analysis. Excessive wear appears to be predominantly dependent on cup orientation, with inclination error having a higher influence than version error, according to the study findings. Acetabular cup loosening, as inferred from initial implant stability, appears to depend predominantly on factors concerning the area of cup-bone contact, specifically the level of cup seating achieved and the individual patient’s anatomy. The extent of press fit obtained at time of surgery did not appear to influence either mechanism of failure in this study. PMID:22513086

Clarke, S G; Phillips, A T M; Bull, A M J; Cobb, J P

2014-01-01

85

Wear of surface-engineered metal-on-metal bearings for hip prostheses under adverse conditions with the head loading on the rim of the cup.  

PubMed

Clinical studies have found high wear rates, elevated ion levels and high revision rates of large-diameter metal-on-metal surface replacement bearings in some patients, which have been associated with edge loading of the head on the rim of the cup. We have simulated increased wear and ion levels in metal-on-metal bearings in vitro by introducing variations in translational and rotational positioning of the components, which reproduces stripe wear on the femoral head, cup rim wear and clinically relevant large as well as small wear particles. There is interest in technologies such as surface engineering, which might reduce metal wear and the release of wear particles and ions. Reduced wear with surface-engineered surface replacements compared to metal-on-metal controls has been reported under standard walking conditions with correctly aligned and concentric components. In this in vitro study, the wear of chromium nitride surface-engineered metal-on-metal bearings under conditions of microseparation associated with translational and rotational malpositioning of the components was investigated and the results were compared with a previously reported study of metal-on-metal bearings under the same conditions. Simulations were conducted using our unique hip simulation microseparation methodologies, which reproduce accelerated wear in metal-on-metal bearings and have previously been clinically validated with ceramic-on-ceramic bearings. Four of the six surface-engineered bearings had evidence of head contact on the rim of the cup, which produced stripe wear on the femoral head. Four of the six surface-engineered bearings (two without stripe and two with stripe wear) had lower wear than the previously reported high wearing metal-on-metal bearings. At 2 million cycles, two of the surface-engineered bearings had substantially increased wear rates, four times higher than the high wear rates previously reported for metal-on-metal bearings under the same conditions. There was wear through and cohesive failure of the thick atomic emission physical vapour deposition (AEPVD) chromium nitride (CrN) coating. At this point, the study was stopped to investigate the failure mode. This study highlights the need to pre-clinically investigate the tribology of new bearings under a wide set of clinical conditions as demonstrated by our stratified approach for enhanced reliability (SAFER) simulation methods. In adopting this SAFER approach to pre-clinical simulation testing of new bearings, it is important to communicate the failures as well as successes of technologies arising from the research, in order that the wider community can benefit from the analysis of the pre-clinical failure modes. PMID:23637209

Leslie, Ian; Williams, Sophie; Isaac, Graham; Hatto, Peter; Ingham, Eileen; Fisher, John

2013-04-01

86

Comparison of in vivo and simulator-retrieved metal-on-metal cervical disc replacements  

PubMed Central

Background Cervical disc arthroplasty is regarded as a promising treatment for myelopathy and radiculopathy as an alternative to cervical spine fusion. On the basis of 2-year clinical data for the PRESTIGE® Cervical Disc (Medtronic, Memphis, Tennessee), the Food and Drug Administration recommended conditional approval in September 2006 and final approval in July 2007; however, relatively little is known about its wear and damage modes in vivo. The main objective was to analyze the tribological findings of the PRESTIGE® Cervical Disc. This study characterized the in vivo wear patterns of retrieved cervical discs and tested the hypothesis that the total disc replacements exhibited similar surface morphology and wear patterns in vitro as in vivo. Methods Ten explanted total disc replacements (PRESTIGE®, PRESTIGE® I, and PRESTIGE® II) from 10 patients retrieved after a mean of 1.8 years (range, 0.3–4.1 years) were analyzed. Wear testing included coupled lateral bending ( ±4.7°) and axial rotation ( ±3.8°) with a 49 N axial load for 5 million cycles followed by 10 million cycles of flexion-extension ( ±9.7°) with 148 N. Implant surfaces were characterized by the use of white-light interferometry, scanning electron microscopy, and energy dispersive spectroscopy. Results The explants generally exhibited a slightly discolored, elliptic wear region of varying dimension centered in the bearing center, with the long axis oriented in the medial-lateral direction. Abrasive wear was the dominant in vivo wear mechanism, with microscopic scratches generally oriented in the medial-lateral direction. Wear testing resulted in severe abrasive wear in a curvilinear fashion oriented primarily in the medial-lateral direction. All retrievals showed evidence of an abrasive wear mechanism. Conclusions This study documented important similarity between the wear mechanisms of components tested in vitro and explanted PRESTIGE® Cervical Discs; however, the severity of wear was much greater during the in vitro test compared with the retrievals. PMID:25694884

Kurtz, Steven M.; Ciccarelli, Lauren; Harper, Megan L.; Siskey, Ryan; Shorez, Jacob; Chan, Frank W.

2012-01-01

87

Auditory and Visual Health after Ten Years of Exposure to Metal-on-Metal Hip Prostheses: A Cross-Sectional Study Follow Up  

PubMed Central

Case reports of patients with mal-functioning metal-on-metal hip replacement (MoMHR) prostheses suggest an association of elevated circulating metal levels with visual and auditory dysfunction. However, it is unknown if this is a cumulative exposure effect and the impact of prolonged low level exposure, relevant to the majority of patients with a well-functioning prosthesis, has not been studied. Twenty four male patients with a well-functioning MoMHR and an age and time since surgery matched group of 24 male patients with conventional total hip arthroplasty (THA) underwent clinical and electrophysiological assessment of their visual and auditory health at a mean of ten years after surgery. Median circulating cobalt and chromium concentrations were higher in patients after MoMHR versus those with THA (P<0.0001), but were within the Medicines and Healthcare Products Regulatory Agency (UK) investigation threshold. Subjective auditory tests including pure tone audiometric and speech discrimination findings were similar between groups (P>0.05). Objective assessments, including amplitude and signal-to-noise ratio of transient evoked and distortion product oto-acoustic emissions (TEOAE and DPOAE, respectively), were similar for all the frequencies tested (P>0.05). Auditory brainstem responses (ABR) and cortical evoked response audiometry (ACR) were also similar between groups (P>0.05). Ophthalmological evaluations, including self-reported visual function by visual functioning questionnaire, as well as binocular low contrast visual acuity and colour vision were similar between groups (P>0.05). Retinal nerve fibre layer thickness and macular volume measured by optical coherence tomography were also similar between groups (P>0.05). In the presence of moderately elevated metal levels associated with well-functioning implants, MoMHR exposure does not associate with clinically demonstrable visual or auditory dysfunction. PMID:24621561

Prentice, Jennifer R.; Blackwell, Christopher S.; Raoof, Naz; Bacon, Paul; Ray, Jaydip; Hickman, Simon J.; Wilkinson, J. Mark

2014-01-01

88

Repeated magnetic resonance imaging in 154 hips with large-diameter metal-on-metal hip replacement  

PubMed Central

Background and purpose — The US Food and Drug Administration and the UK Medicines and Health Regulation Agency recommend using MRI in the evaluation of patients with large-diameter metal-on-metal (LD-MoM) hips. Such recommendations do not take into account the relevance of repeated cross-sectional imaging. We therefore investigated the natural course of pseudotumors in patients with LD-MoM hip replacements. Patients and methods — Of 888 ASR patients (1,036 hips) 674 patients (798 hips) underwent 2 follow-up visits at our institution. Of these, we identified 124 patients (154 hips) who had undergone repeated clinical assessment including MRI and whole-blood metal ion assessment. Results — A change in classification in imaging findings between the 2 MRIs was seen in 17 of the 154 hips (11%). In 13 hips (8%), a significant progression of the pseudotumor was evident, while in 4 (3 %) there was a retrogressive change. 10 of these 13 hips had had a normal first MRI. Patients with a progressive change in the scans did not differ significantly from those without a change in MRI classification regarding follow-up time, time interval between MRIs, or changes in whole-blood Cr and Co levels between assessments. Interpretation — A change in classification was rare, considering that all patients had a clinical indication for repeated imaging. Progression of the findings did not appear to correlate clearly with symptoms or whole-blood metal values. PMID:25238435

Reito, Aleksi; Elo, Petra; Puolakka, Timo; Pajamäki, Jorma; Nieminen, Jyrki; Eskelinen, Antti

2014-01-01

89

Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties  

PubMed Central

Background and purpose Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties. Methods Studies were searched for in the Medline database, Embase, and the Cochrane Database of Systematic Reviews. Highest mean or median ion concentrations of Cr and Co after a minimum of 1 year of follow-up were extracted and grouped according to sample- and articulation type, and average values were calculated. Results 43 studies were included and 16 different MoM implants were identified. For the different types of bearings, average ion concentrations and range were calculated from the mean or median ion concentration. The average Cr concentration ranged between 0.5 and 2.5 ?g/L in blood and between 0.8 and 5.1 ?g/L in serum. For Co, the range was 0.7–3.4 ?g/L in blood and 0.3–7.5 ?g/L in serum. Interpretation When the average blood ion concentrations calculated for the different implants, together with the concentrations measured in the individual studies, were compared with the upper acceptable limit for Cr and Co in blood, no clear pattern was recognized. Furthermore, we were unable to detect any clear difference in ion concentrations between different types of implants (THA and resurfacing). PMID:23594249

2013-01-01

90

A comparison of the diagnostic accuracy of MARS MRI and ultrasound of the painful metal-on-metal hip arthroplasty  

PubMed Central

Background and purpose Metal artifact reduction sequence (MARS) MRI and ultrasound scanning (USS) can both be used to detect pseudotumors, abductor muscle atrophy, and tendinous pathology in patients with painful metal-on-metal (MOM) hip arthroplasty. We wanted to determine the diagnostic test characteristics of USS using MARS MRI as a reference for detection of pseudotumors and muscle atrophy. Patients and methods We performed a prospective cohort study to compare MARS MRI and USS findings in 19 consecutive patients with unilateral MOM hips. Protocolized USS was performed by consultant musculoskeletal radiologists who were blinded regarding clinical details. Reports were independently compared with MARS MRI, the imaging gold standard, to calculate predictive values. Results The prevalence of pseudotumors on MARS MRI was 68% (95% CI: 43–87) and on USS it was 53% (CI: 29–76). The sensitivity of USS in detecting pseudotumors was 69% (CI 39–91) and the specificity was 83% (CI: 36–97). The sensitivity of detection of abductor muscle atrophy was 47% (CI: 24–71). In addition, joint effusion was detected in 10 cases by USS and none were seen by MARS MRI. Interpretation We found a poor agreement between USS and MARS MRI. USS was inferior to MARS MRI for detection of pseudotumors and muscle atrophy, but it was superior for detection of joint effusion and tendinous pathologies. MARS MRI is more advantageous than USS for practical reasons, including preoperative planning and longitudinal comparison. PMID:24694273

Siddiqui, Imran A; Sabah, Shiraz A; Satchithananda, Keshthra; Lim, Adrian K; Cro, Suzie; Henckel, Johann; Skinner, John A

2014-01-01

91

Effect of microseparation on contact mechanics in metal-on-metal hip replacements-A finite element analysis.  

PubMed

Some early failures of metal-on-metal (MoM) hip replacements associated with elevated wear have caused concerns for the use of this bearing combination. Simulator studies have shown that microseparation and its associated rim contact and edge loading may produce the most severe wear in MoM bearings. It is generally recognized that this high wear can be attributed to the high contact stress of the head on the rim of the cup. In this study, an improved finite element contact model that incorporates an elastic-perfectly plastic material property for cobalt-chrome alloy of the metal bearing was developed in an attempt to provide an accurate prediction of the stress and strain for the rim contact. The effects of the microseparation displacement (0.1-2 mm), cup inclination angle (25-65°) and cup rim radius (0.5-4 mm) on the contact stress/strain were investigated. The results show that a translational displacement >0.1 mm under a load >0.5 kN can produce a highly concentrated contact stress at the surface of the cup rim which can lead to plastic deformation. This study also suggests that the magnitude of translational displacement was the major factor that determined the severity of the contact conditions and level of stress and strain under microseparation conditions. Future studies will address the effect of surgical translational and rotational malposition and component design on the magnitude of microseparation, contact stress and strain and severity of wear. © 2014 The Authors. Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014. PMID:25370809

Liu, Feng; Williams, Sophie; Fisher, John

2014-11-01

92

Lymphoid Aggregates That Resemble Tertiary Lymphoid Organs Define a Specific Pathological Subset in Metal-on-Metal Hip Replacements  

PubMed Central

Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) has been used to describe the histological lesion associated with metal-on-metal (M-M) bearings. We tested the hypothesis that the lymphoid aggregates, associated with ALVAL lesions resemble tertiary lymphoid organs (TLOs). Histopathological changes were examined in the periprosthetic tissue of 62 M-M hip replacements requiring revision surgery, with particular emphasis on the characteristics and pattern of the lymphocytic infiltrate. Immunofluorescence and immunohistochemistry were used to study the classical features of TLOs in cases where large organized lymphoid follicles were present. Synchrotron X-ray fluorescence (XRF) measurements were undertaken to detect localisation of implant derived ions/particles within the samples. Based on type of lymphocytic infiltrates, three different categories were recognised; diffuse aggregates (51%), T cell aggregates (20%), and organised lymphoid aggregates (29%). Further investigation of tissues with organised lymphoid aggregates showed that these tissues recapitulate many of the features of TLOs with T cells and B cells organised into discrete areas, the presence of follicular dendritic cells, acquisition of high endothelial venule like phenotype by blood vessels, expression of lymphoid chemokines and the presence of plasma cells. Co-localisation of implant-derived metals with lymphoid aggregates was observed. These findings suggest that in addition to the well described general foreign body reaction mediated by macrophages and a T cell mediated type IV hypersensitivity response, an under-recognized immunological reaction to metal wear debris involving B cells and the formation of tertiary lymphoid organs occurs in a distinct subset of patients with M-M implants. PMID:23723985

Barone, Francesca; Hardie, Debbie L.; Matharu, Gulraj S.; Davenport, Alison J.; Martin, Richard A.; Grant, Melissa; Mosselmans, Frederick; Pynsent, Paul; Sumathi, Vaiyapuri P.; Addison, Owen; Revell, Peter A.; Buckley, Christopher D.

2013-01-01

93

A simulator study of adverse wear with metal and cement debris contamination in metal-on-metal hip bearings  

PubMed Central

Objectives Third-body wear is believed to be one trigger for adverse results with metal-on-metal (MOM) bearings. Impingement and subluxation may release metal particles from MOM replacements. We therefore challenged MOM bearings with relevant debris types of cobalt–chrome alloy (CoCr), titanium alloy (Ti6Al4V) and polymethylmethacrylate bone cement (PMMA). Methods Cement flakes (PMMA), CoCr and Ti6Al4V particles (size range 5 µm to 400 µm) were run in a MOM wear simulation. Debris allotments (5 mg) were inserted at ten intervals during the five million cycle (5 Mc) test. Results In a clean test phase (0 Mc to 0.8 Mc), lubricants retained their yellow colour. Addition of metal particles at 0.8 Mc turned lubricants black within the first hour of the test and remained so for the duration, while PMMA particles did not change the colour of the lubricant. Rates of wear with PMMA, CoCr and Ti6Al4V debris averaged 0.3 mm3/Mc, 4.1 mm3/Mc and 6.4 mm3/Mc, respectively. Conclusions Metal particles turned simulator lubricants black with rates of wear of MOM bearings an order of magnitude higher than with control PMMA particles. This appeared to model the findings of black, periarticular joint tissues and high CoCr wear in failed MOM replacements. The amount of wear debris produced during a 500 000-cycle interval of gait was 30 to 50 times greater than the weight of triggering particle allotment, indicating that MOM bearings were extremely sensitive to third-body wear. Cite this article: Bone Joint Res 2015;4:29–37. PMID:25736072

Halim, T.; Clarke, I. C.; Burgett-Moreno, M. D.; Donaldson, T. K.; Savisaar, C.; Bowsher, J. G.

2015-01-01

94

(v) Simulation and measurement of wear in metal-on-metal bearings in vitro- understanding the reasons for increased wear  

PubMed Central

A new Stratified Approach For Enhanced Reliability (SAFER) pre-clinical simulation testing of joint prostheses has been described in a preceding paper in this volume. The application of SAFER in vitro simulation and testing to metal-on-metal bearings is described in this review paper. The review aims to provide further understanding of the reasons for, and causes of, increased wear in metal-on-metal hips in a proportion of patients. Variation in positioning (mal-positioning) of the head and cup in hip prostheses results in the head contacting the rim of the cup and producing increased wear. Variation in both translational and rotational positioning has been investigated. Variation in translational positioning of the centres of the head and cup, which is not detected on radiographs, is a frequent occurrence clinically and can result in a substantial increase in wear rate. The variation in translational positioning acts synergistically with variation in rotational positioning to produce substantial increases in wear. These recent findings are consistent with the wear mechanisms and formation of stripe wear reported for ceramic-on-ceramic bearings over a decade ago, and provide insight into the reasons for the variation and increases in the wear rate found clinically in metal-on-metal hips in specific patients, which may cause premature failure. PMID:23335950

Fisher, John; Al Hajjar, Mazen; Williams, Sophie; Tipper, Joanne; Ingham, Eileen; Jennings, Louise

2012-01-01

95

A Two Centre Study to Assess the Long-term Performance of the Pinnacle™ Cup With a Metal-on-Metal Bearing in Primary Total Hip Replacement  

ClinicalTrials.gov

Rheumatoid Arthritis; Osteoarthritis; Post-traumatic Arthritis; Collagen Disorders; Avascular Necrosis; Traumatic Femoral Fractures; Nonunion of Femoral Fractures; Congenital Hip Dysplasia; Slipped Capital Femoral Epiphysis

2014-04-29

96

Is increased modularity associated with increased fretting and corrosion damage in metal-on-metal total hip arthroplasty devices?: a retrieval study.  

PubMed

This retrieval study documents taper damage at modular interfaces in retrieved MOM THA systems and investigates if increased modularity is associated with increased fretting and corrosion. One hundred thirty-four (134) heads and 60 stems (41 modular necks) of 8 different bearing designs (5 manufacturers) were analyzed. Damage at the shell-liner interface of 18 modular CoCr acetabular liners and the corresponding 11 acetabular shells was also evaluated. The results of this study support the hypothesis that fretting and corrosion damage occurs at a variety of modular component interfaces in contemporary MOM THAs. We also found that modularity of the femoral stem was associated with increased damage at the head. An analysis of component and patient variables revealed that dissimilar alloy pairing, larger head sizes, increased medio-lateral offsets and longer neck moment arms were all associated with increased taper damage at the modular interfaces. PMID:23910820

Higgs, Genymphas B; Hanzlik, Josa A; MacDonald, Daniel W; Gilbert, Jeremy L; Rimnac, Clare M; Kurtz, Steven M

2013-09-01

97

Evaluation of the accuracy of three popular regression equations for hip joint centre estimation using computerised tomography measurements for metal-on-metal hip resurfacing arthroplasty patients.  

PubMed

We investigated the accuracy of the regression equations by Bell et al., Davis III et al. and Harrington et al. for hip joint centre (HJC) estimation against the gold standard of computerised tomography (CT) measurements of HJC for 18 patients with metal-on-metal hip resurfacing arthroplasty (MoMHRA). The HJCs were estimated based on the position of the left and right Anterior Superior Iliac Spine (ASIS) and the left and right Posterior Superior Iliac Spine (PSIS) identified from a CT scan. Of the three tested regression equations, only those of Harrington et al. produced results that were not significantly different from the patient's 'true' HJCs as measured from the CT scan in all three directions when analysing left and right hips together for both resurfaced and native hips. When native and resurfaced hips were pooled and analysed for left and right, separately, the Harrington et al. regression equations showed significantly different results in the ML direction. Similar estimation errors were observed for native and resurfaced hips. Since none of the methods tested performed particularly well, we suggest using medical imaging if accurate estimates of HJCs are required. PMID:23454045

Andersen, Michael S; Mellon, Stephen; Grammatopoulos, George; Gill, Harinderjit S

2013-09-01

98

Influence of head size on the development of metallic wear and on the characteristics of carbon layers in metal-on-metal hip joints  

PubMed Central

Background and purpose Particles originating from the articulating surfaces of hip endoprostheses often induce an inflammatory response, which can be related to implant failure. We therefore analyzed the metal content in capsular tissue from 44 McKee-Farrar metal-on-metal hip prostheses (with 3 different head sizes) and we also analyzed the morphological structure of layers located on articulating surfaces. Methods Atomic absorption spectrometry (AAS) was used to analyze the metal content in capsular tissue. Visually detectable carbon layers located on the articulating surfaces were evaluated using scanning electron microscopy (SEM), energy-dispersive Xray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Results Metallic debris was detected in all capsular tissue samples but no statistically significant differences in metal content were found in relation to implant head size. The morphological characteristics of the different layer zones allowed an exact analysis of contact and non-contact areas. Furthermore, surface layers appear to have a protective function because they can prevent sharp-edged particles from damaging the prostheses surface. Interpretation The implant head size does not appear to influence the amount of metallic debris. The layers obviously act like a lubricating agent because the protection function does not occur in regions without layers where the metal surface often shows numerous scratches. As layers are not generated immediately after the implantation of hip prostheses, these findings may at least partially explain the high amount of wear early after implantation. PMID:19421914

Sprecher, Christoph M; Wimmer, Markus A; Milz, Stefan; Taeger, Georg

2009-01-01

99

Comparison of extracapsular pseudotumors seen in magnetic resonance imaging and in revision surgery of 167 failed metal-on-metal hip replacements  

PubMed Central

Background and purpose Magnetic resonance imaging (MRI) is important for detecting extracapsular pseudotumors, but there is little information on the accuracy of MRI and appropriate intervals for repeated imaging. We evaluated the sensitivity and specificity of MRI for detecting pseudotumors in 155 patients (167 hips) with metal-on-metal (MoM) hip arthroplasties that failed due to adverse reactions to metal debris (ARMD). Methods Preoperative MRIs were performed with two 1.5 T MRI scanners and graded by a senior musculoskeletal radiologist using a previously described MRI pseudotumor grading system. Revision findings were retrieved from surgical notes, and pseudotumors were retrospectively graded as fluid-filled, mixed-type, or solid. Results The sensitivity of MRI was 71% and the specificity was 87% for detecting extracapsular pseudotumors. The sensitivity was 88% (95% CI: 70–96) when MRI was performed less than 3 months before the revision surgery. Interestingly, when the time that elapsed between MRI and revision was more than 1 year, the sensitivity calculated was only 29% (95% CI: 14–56). Comparison between MRI and revision classifications gave moderate agreement (Cohen’s kappa = 0.4). Interpretation A recent MRI predicts the presence of a pseudotumor well, but there is more discrepancy when the MRI examination is over a year old, most likely due to the formation of new pseudotumors. 1 year could be a justifiable limit for considering a new MRI if development of ARMD is suspected. MRI images over a year old should not be used in decision making or in planning of revision surgery for MoM hips. PMID:24954485

Lainiala, Olli; Elo, Petra; Reito, Aleksi; Pajamäki, Jorma; Puolakka, Timo

2014-01-01

100

An in vitro study of the reduction in wear of metal-on-metal hip prostheses using surface-engineered femoral heads.  

PubMed

Although the wear of existing metal-on-metal (MOM) hip prostheses (1 mm3/10(6) cycles) is much lower than the more widely used polyethylene-on-metal bearings, there are concerns about the toxicity of metal wear particles and elevated metal ion levels, both locally and systemically, in the human body. The aim of this study was to investigate the possibility of reducing the volume of wear, the concentration of metal debris and the level of metal ion release through using surface-engineered femoral heads. Three thick (8-12 microm) coatings (TiN, CrN and CrCN) and one thin (2 microm) coating (diamond-like carbon, DLC), were evaluated on the femoral heads when articulating against high carbon content cobalt-chromium alloy acetabular inserts (HC CoCrMo) and compared with a clinically used MOM cobalt-chromium alloy bearing couple using a physiological anatomical hip joint simulator (Leeds Mark II). This study showed that CrN, CrCN and DLC coatings produced substantially lower wear volumes for both the coated femoral heads and the HC CoCrMo inserts. The TiN coating itself had little wear, but it caused relatively high wear of the HC CoCrMo inserts compared with the other coatings. The majority of the wear debris for all half-coated couples comprised small, 30 nm or less, CoCrMo metal particles. The Co, Cr and Mo ion concentrations released from the bearing couples of CrN-, CrCN- and DLC-coated heads articulating against HC CoCrMo inserts were at least 7 times lower than those released from the clinical MOM prostheses. These surface-engineered femoral heads articulating on HC CoCrMo acetabular inserts produced significantly lower wear volumes and rates, and hence lower volumetric concentrations of wear particles, compared with the clinical MOM prosthesis. The substantially lower ion concentration released by these surface-engineered components provides important evidence to support the clinical application of this technology. PMID:12206518

Fisher, J; Hu, X Q; Tipper, J L; Stewart, T D; Williams, S; Stone, M H; Davies, C; Hatto, P; Bolton, J; Riley, M; Hardaker, C; Isaac, G H; Berry, G; Ingham, E

2002-01-01

101

Peri-acetabular bone mineral density in total hip replacement  

PubMed Central

Objectives To quantify and compare peri-acetabular bone mineral density (BMD) between a monoblock acetabular component using a metal-on-metal (MoM) bearing and a modular titanium shell with a polyethylene (PE) insert. The secondary outcome was to measure patient-reported clinical function. Methods A total of 50 patients (25 per group) were randomised to MoM or metal-on-polyethlene (MoP). There were 27 women (11 MoM) and 23 men (14 MoM) with a mean age of 61.6 years (47.7 to 73.2). Measurements of peri-prosthetic acetabular and contralateral hip (covariate) BMD were performed at baseline and at one and two years’ follow-up. The Western Ontario and McMaster Universities osteoarthritis index (WOMAC), University of California, Los Angeles (UCLA) activity score, Harris hip score, and RAND-36 were also completed at these intervals. Results At two years, only zone 1 showed a loss in BMD (-2.5%) in MoM group compared with a gain in the MoP group (+2.2%). Zone 2 showed loss in both groups (-2.2% for MoM; -3.9% for MoP) and zones 3 and 4 a gain in both groups (+0.1% for MoM; +3.3% for MoP). No other between-group differences were detected. When adjusting for BMD of the contralateral hip, no differences in BMD were observed. The only significant differences in functional scores at two years were higher UCLA activity (7.3 (sd 1.2) vs 6.1 (sd 1.5); p = 0.01) and RAND-36 physical function (82.1 (sd 13.0) vs 64.5 (sd 26.4); p = 0.02) for MoM bearings versus MoP. One revision was performed in the MoM group, for aseptic acetabular loosening at 11 months. Conclusions When controlling for systemic BMD, there were no significant differences between MoM and MoP groups in peri-acetabular BMD. However, increasing reports of adverse tissue reactions with large head MoM THR have restricted the use of the monoblock acetabular component to resurfacing only. PMID:23913361

Gauthier, L.; Dinh, L.; Beaulé, P. E.

2013-01-01

102

Biomaterial Hypersensitivity: Is It Real? Supportive Evidence and Approach Considerations for Metal Allergic Patients following Total Knee Arthroplasty  

PubMed Central

The prospect of biomaterial hypersensitivity developing in response to joint implant materials was first presented more than 30 years ago. Many studies have established probable causation between first-generation metal-on-metal hip implants and hypersensitivity reactions. In a limited patient population, implant failure may ultimately be related to metal hypersensitivity. The examination of hypersensitivity reactions in current-generation metal-on-metal knee implants is comparatively limited. The purpose of this study is to summarize all available literature regarding biomaterial hypersensitivity after total knee arthroplasty, elucidate overall trends about this topic in the current literature, and provide a foundation for clinical approach considerations when biomaterial hypersensitivity is suspected.

Mihalko, William M.; Grupp, Thomas M.; Manning, Blaine T.; Dennis, Douglas A.; Goodman, Stuart B.; Saleh, Khaled J.

2015-01-01

103

Rapid chromosomal analysis of germ-line cells by FISH: an investigation of an infertile male with large-headed spermatozoa.  

PubMed

A rapid fluorescence in-situ hybridization (FISH) technique was used for direct chromosomal analysis on germ cells from an infertile male with large-headed spermatozoa. The interphase chromosomes were fluorescently-labelled using an extremely bright cyanine dye during a 5-15 min FISH procedure. Germ cells were analysed using a battery of chromosome-specific DNA probes in several consecutive rapid FISH experiments. It was found that the majority of large-headed spermatozoa contained a diploid chromosome number probably due to errors in meiosis I or II divisions, whereas the majority of spermatozoa with normal sized heads are haploid and may be utilized for selective in-vitro fertilization procedures. Rapid FISH may be useful for the detection of major chromosomal aneuploidies in germ cells as an alternative technique to standard or multicolour FISH, and may find an additional application for the chromosomal analysis of human preimplantation embryos. PMID:9239680

Yurov, Y B; Saias, M J; Vorsanova, S G; Erny, R; Soloviev, I V; Sharonin, V O; Guichaoua, M R; Luciani, J M

1996-09-01

104

Un couple de frottement métal-métal peut-il améliorer la longévité des prothčses totales de hanche ?  

Microsoft Academic Search

Purpose of the studyIn total hip arthroplasty (THA), inter-series comparative clinical results cannot be considered worthy before at least 10 years of average follow-up, as shown in the Swedish Arthroplasty Register experience (1978-1993). Last generation metal-on-metal bearings were introduced in France only nine years ago (1995). To date, using mid term information, data from the literature, and our experience, one

C. Delaunay

2005-01-01

105

Prediction of Impact Shock Vibrations at Tennis Player's Wrist Joint: Comparison between Conventional Weight Racket and Light Weight Racket with Super Large Head Size  

NASA Astrophysics Data System (ADS)

The lightweight racket with handle-light configuration and large head size is recent tendency of high-tech tennis rackets, increasing power or post-impact ball velocity with an increasing racket swing speed. This paper investigated the performance of lightweight tennis racket with super-large head size in terms of feel or comfort. It predicted the effect of the mass and mass distribution of super-large sized rackets on the impact shock vibrations of the racket handle and the player's wrist joint when a player hits a flat forehand drive. The prediction is based on the identification of the racket characteristics, the damping of the racket-arm system, equivalent mass of the player's arm system and the approximate nonlinear impact analysis in tennis. A super-light weight balanced racket (mass: 292 g, the center of gravity LG: 363 mm from the butt end) and a conventional weight and weight balanced racket (349 g, LG: 323 mm) are selected as representatives. They are the super-large sized rackets made of carbon graphite with a head size of 120 square inches and the same geometry. The result showed that the shock vibration of the super-light weight balanced racket with super-large sized head is much larger than that of the conventional weight balanced type racket. It also showed that the sweet area of the former in terms of the shock vibration shifts from the center to the topside on the racket face compared to the latter. This is because the location of the grip on the racket handle is further from the location of the node on the handle of the first mode of super-light racket than that of the conventional weight racket.

Kawazoe, Yoshihiko; Takeda, Yukihiro; Nakagawa, Masamichi; Casolo, Federico; Tomosue, Ryoso; Yoshinari, Keiko

106

Inflammatory Pseudotumor Complicated by Recurrent Dislocations after Revision Total Hip Arthroplasty  

PubMed Central

A 71-year-old female with a history of right total hip arthroplasty presented with an enlarging pseudotumor. Pseudotumor is a known complication following metal-on-metal and metal-on-conventional polyethylene and metal-on-highly cross-linked polyethylene implants. Revision total hip arthroplasty following resection of pseudotumor has resulted in an increase in incidence of postoperative complications. Despite stable implants, these complications arise from the amount of soft tissue damage combined with the loss of tissue support around the resected hip. Our case is a clear example of a major complication, recurrent dislocation, following resection and revision surgery. PMID:25161791

Lee, Jason; Schwarzkopf, Ran

2014-01-01

107

A Novel Bradykinin-Related Dodecapeptide (RVALPPGFTPLR) from the Skin Secretion of the Fujian Large-Headed Frog (Limnonectes fujianensis) Exhibiting Unusual Structural and Functional Features  

PubMed Central

Bradykinin-related peptides (BRPs) are significant components of the defensive skin secretions of many anuran amphibians, and these secretions represent the source of the most diverse spectrum of such peptides so far encountered in nature. Of the many families of bioactive peptides that have been identified from this source, the BRPs uniquely appear to represent homologues of counterparts that have specific distributions and receptor targets within discrete vertebrate taxa, ranging from fishes through mammals. Their broad spectra of actions, including pain and inflammation induction and smooth muscle effects, make these peptides ideal weapons in predator deterrence. Here, we describe a novel 12-mer BRP (RVALPPGFTPLR-RVAL-(L1, T6, L8)-bradykinin) from the skin secretion of the Fujian large-headed frog (Limnonectes fujianensis). The C-terminal 9 residues of this BRP (-LPPGFTPLR) exhibit three amino acid substitutions (L/R at Position 1, T/S at Position 6 and L/F at Position 8) when compared to canonical mammalian bradykinin (BK), but are identical to the kinin sequence present within the cloned kininogen-2 from the Chinese soft-shelled turtle (Pelodiscus sinensis) and differ from that encoded by kininogen-2 of the Tibetan ground tit (Pseudopodoces humilis) at just a single site (F/L at Position 8). These data would imply that the novel BRP is an amphibian defensive agent against predation by sympatric turtles and also that the primary structure of the avian BK, ornithokinin (RPPGFTPLR), is not invariant within this taxon. Synthetic RVAL-(L1, T6, L8)-bradykinin was found to be an antagonist of BK-induced rat tail artery smooth muscle relaxation acting via the B2-receptor. PMID:25268979

Shi, Daning; Luo, Yu; Du, Qiang; Wang, Lei; Zhou, Mei; Ma, Jie; Li, Renjie; Chen, Tianbao; Shaw, Chris

2014-01-01

108

Early failures in total hip arthroplasty -- a changing paradigm.  

PubMed

Between 2001 and 2011, 1168 revision hip arthroplasties were reviewed for "early" failures within 5 years of the primary total hip arthroplasty (THA). 24.1% underwent revision within 5 years of index THA. Aseptic loosening, infection, instability, metallosis, and fracture were common modes of failure. In our previous report from 1986 to 2000, 33% were "early" revisions, with instability and aseptic loosening accounting for over 70% of these early failures. While the proportion of "early" revisions decreased 9% from our previous report, this rate remains alarming. The emergence of metallosis and aseptic loosening of monoblock metal on metal shells as leading causes of early failures is concerning. This report suggests caution in the early adoption of new innovations before evidence based medicine is available to justify the risk of their use. PMID:24444568

Melvin, J Stuart; Karthikeyan, Tharun; Cope, Robert; Fehring, Thomas K

2014-06-01

109

Femoral head diameter considerations for primary total hip arthroplasty.  

PubMed

The configuration of total hip arthroplasty (THA) implants has constantly evolved since they were first introduced. One of the key components of THA design is the diameter of the prosthetic femoral head. It has been well established that the risk of dislocation is lower as the head diameter increases. But head diameter impacts other variables beyond joint stability: wear, cam-type impingement, range of motion, restoration of biomechanics, proprioception and groin pain. The introduction of highly cross-linked polyethylene and hard-on-hard bearings has allowed surgeons to implant large-diameter heads that almost completely eliminate the risk of dislocation. But as a result, cup liners have become thinner. With femoral head diameters up to 36 mm, the improvement in joint range of motion, delay in cam-type impingement and reduction in dislocation risk have been clearly demonstrated. Conversely, large-diameter heads do not provide any additional improvements. If an "ecologically sound" approach to hip replacement is embraced (e.g. keeping the native femoral head diameter), hip resurfacing with a metal-on-metal bearing must be carried out. The reliability of large-diameter femoral heads in the longer term is questionable. Large-diameter ceramic-on-ceramic bearings may be plagued by the same problems as metal-on-metal bearings: groin pain, squeaking, increased stiffness, irregular lubrication, acetabular loosening and notable friction at the Morse taper. These possibilities require us to be extra careful when using femoral heads with a diameter greater than 36 mm. PMID:25596984

Girard, J

2015-02-01

110

Early metallosis-related failure after total knee replacement: a report of 15 cases.  

PubMed

Metallosis is a rare cause of failure after total knee replacement and has only previously been reported when there has been abnormal metal-on-metal contact. We describe 14 patients (15 knees) whose total knee replacement required revision for a new type of early failure caused by extensive metallosis. A modification of a cementless rotating platform implant, which had previously had excellent long-term survival, had been used in each case. The change was in the form of a new porous-beaded surface on the femoral component to induce cementless fixation, which had been used successfully in the fixation of acetabular and tibial components. This modification appeared to have resulted in metallosis due to abrasive two-body wear. The component has subsequently been recalled and is no longer in use. The presentation, investigation, and findings at revision are described and a possible aetiology and its implications are discussed. PMID:21282760

Willis-Owen, C A; Keene, G C; Oakeshott, R D

2011-02-01

111

Enrollment Statistics -Engineering TOTAL M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total  

E-print Network

Enrollment Statistics - Engineering TOTAL M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total Spring 2000 Freshmen 256 8 3 11 19 15 Senior 806 11 9 20 56 34 90 158 26 184 143 16 159 124 18 142 159 24 183 9 3 12 14 2 16 BS Total 1727 MS

Hayes, Jane E.

112

Total protein  

MedlinePLUS

The total protein test measures the total amount of two classes of proteins found in the fluid portion of your blood. These are albumin and globulin. Proteins are important parts of all cells and tissues. ...

113

Primary musculoskeletal mycobacterium infection with large cystic masses after total hip arthroplasty.  

PubMed

Primary mycobacterial infections in the musculoskeletal system are rare with a limited number of published case reports. This report describes a case involving a primary musculoskeletal tuberculous abscess. A 62-year-old male patient who had a right total hip arthroplasty performed 8 years earlier, using metal-on-metal articulation presented with a 1-year history of non-tender masses on his right thigh. Initially, it was assumed he had metallosis. Intraoperatively, an incision into the mass was conducted which resulted in draining of a whitish-grey pus like fluid. A diagnosis of tuberculosis was confirmed with both microscopic and histological examination. The patient was treated over a course of six months with an anti-tuberculosis medication regimen following the confirmation of a solitary soft tissue tuberculosis infection. At the 24 month follow-up, the patient was asymptomatic with no relapse of the mass. PMID:22749661

Lee, Han-Jun; Kim, Kyoung-Woon; Kim, Ki Seong; Ryu, Sung Hwa; Ha, Yong-Chan

2013-02-01

114

TOTAL M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total Spring 2010  

E-print Network

TOTAL M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total Spring 2010 Freshmen 400 4 4 8 31 13 44 63 13 76 34 2 36 27 5 32 27 2 29 106 8 34 3 37 0 1 1 X X BS Total 1943 57 236 363 119 180 192 603 42 134 17 MS Total 216 18 2 44 X 32 58 39

Hayes, Jane E.

115

Early surveillance of ceramic-on-metal total hip arthroplasty.  

PubMed

Ceramic-on-metal (CoM) is a relatively new bearing combination for total hip arthroplasty (THA) with few reported outcomes. A total of 287 CoM THAs were carried out in 271 patients (mean age 55.6 years (20 to 77), 150 THAs in female patients, 137 in male) under the care of a single surgeon between October 2007 and October 2009. With the issues surrounding metal-on-metal bearings the decision was taken to review these patients between March and November 2011, at a mean follow-up of 34 months (23 to 45) and to record pain, outcome scores, radiological analysis and blood ion levels. The mean Oxford Hip Score was 19.2 (12 to 53), 254 patients with 268 hips (95%) had mild/very mild/no pain, the mean angle of inclination of the acetabular component was 44.8(o) (28(o) to 63(o)), 82 stems (29%) had evidence of radiolucent lines of > 1 mm in at least one Gruen zone and the median levels of cobalt and chromium ions in the blood were 0.83 ?g/L (0.24 ?g/L to 27.56 ?g/L) and 0.78 ?g/L (0.21 ?g/L to 8.84 ?g/L), respectively. The five-year survival rate is 96.9% (95% confidence interval 94.7% to 99%). Due to the presence of radiolucent lines and the higher than expected levels of metal ions in the blood, we would not recommend the use of CoM THA without further long-term follow-up. We plan to monitor all these patients regularly. Cite this article: Bone Joint J 2015;97-B:300-5. PMID:25737511

Hill, J C; Diamond, O J; O'Brien, S; Boldt, J G; Stevenson, M; Beverland, D E

2015-03-01

116

Serum Metal Ion Concentrations in Paediatric Patients following Total Knee Arthroplasty Using Megaprostheses  

PubMed Central

The purpose of this study was to determine the concentrations of cobalt, chromium, and molybdenum in the serum of paediatric tumour patients after fixed hinge total knee arthroplasty. Further, these metal ion levels were compared with serum metal ion levels of patients with other orthopaedic devices such as hip and knee prostheses with metal-on-metal or metal-on-polyethylene articulation to find differences between anatomical locations, abrasion characteristics, and bearing surfaces. After an average follow-up of 108 months (range: 67 to 163) of 11 paediatric patients with fixed hinge total knee arthroplasty, the mean concentrations for Co and Cr were significantly increased while Mo was within the limits compared to the upper values from the reference laboratory. Furthermore, these serum concentrations were significantly higher compared to patients with a standard rotating hinge device (P = 0.002 and P < 0.001) and preoperative controls (P < 0.001). On the other hand, the serum levels of patients following MoM THA or rotating hinge arthroplasty using megaprostheses were higher. Therefore, periodic long-term follow-ups are recommended due to the rising concerns about systemic metal ion exposure in the literature. Upon the occurrence of adverse reactions to metal debris the revision of the fixed hinge implant should be considered. PMID:25276819

Friesenbichler, Jörg; Sadoghi, Patrick; Maurer-Ertl, Werner; Szkandera, Joanna; Glehr, Mathias; Ogris, Kathrin; Wolf, Matthias; Weger, Christian; Leithner, Andreas

2014-01-01

117

Unit of Enrollment & Degree Level Total Total  

E-print Network

Unit of Enrollment & Degree Level Grand Total Total Total Minorities Black Asian Native American Hispanic White Unknown Nonresident Alien Degrees & Certificates Total 12000 10177 2623 698 1379 79 467 7162 1223 Degrees Total 11079 9543 2454 646 1297 75 436 6701 388 1536 Women 5454 4976 1267 395 629 37 206

Shyy, Wei

118

Total Artificial Heart  

MedlinePLUS

... NHLBI on Twitter. What Is a Total Artificial Heart? A total artificial heart (TAH) is a device ... the chest to an outside power source. Normal Heart and CardioWest Total Artificial Heart Figure A shows ...

119

TETE: Total Education in the Total Environment.  

ERIC Educational Resources Information Center

The Hudson River Museum's Environmental Arts and Science Division has published this booklet describing their model educational program, "TETE: Total Education in the Total Environment," a multidisciplinary approach to environmental education utilizing existing curricula. For conducting the program model communities strategically located along the…

Eblen, William R.

120

Squeaking in Large Diameter Ceramic-on-Ceramic Bearings in Total Hip Arthroplasty.  

PubMed

We analyzed the results of 206 consecutive total hip arthroplasties performed using large diameter ceramic-on-ceramic bearings. At an average follow-up of 28months, the mean Harris Hip Score improved from 54 to 92. Fifteen (7.3%) hips were noted to squeak. There was no significant difference between silent and squeaking hips with regards to age, weight, height, BMI, range of movement, femoral head diameter, leg length, and offset or center of rotation. No correlation was present between incidence of squeaking and increasing cup inclination and anteversion. 5.2% of cups orientated within Lewinnek's safe zone squeaked. No hips required revision for squeaking. While large diameter ceramic bearings may produce squeaking, our early results of surgery using large head ceramic bearings are encouraging. However, long-term follow-up is required. PMID:25304938

Tai, Stephen M; Munir, Selin; Walter, William L; Pearce, Simon J; Walter, William K; Zicat, Bernard A

2015-02-01

121

Total hip arthroplasty in the young: special emphasis on post-SCFE patients.  

PubMed

Slipped capital femoral epiphysis (SCFE) is a hip disorder of adolescence, which has the potential for profound implications into adulthood. SCFE patients are at risk of early joint degeneration and subsequent need for arthroplasty. The rate at which arthroplasty is required is not precisely known, but is estimated to be approximately 45% by 50 years after a slip. The femoral neck and shaft displace anteriorly and rotate externally relative to the femoral epiphysis, which remains fixed in the acetabulum. Stabilization of the physis is the goal of acute management. Despite such efforts, accelerated joint degeneration may occur over time. This progression is due to avascular necrosis, chondrolysis, or following years of femoroacetabular impingement. Total hip arthroplasty (THA) and total hip resurfacing (THR) are options for end-stage hip arthritis due to SCFE. THR is technically more challenging, with very limited ability to address deformity-related issues of impingement, decreased hip offset, and trochanteric malposition. THR, as in any metal on metal arthroplasty, may be associated with local metal sensitivity or systemic metal toxicity. Given the limited utility and potential risks, THR is currently not recommended in the majority of cases. THA, although historically demonstrating poor long-term implant performance in the young patient, has become a more reliable option recently. The potential benefits of THA are considerable, even for the young patient with end-stage hip degeneration. Certain cemented and many cementless stem designs show good long-term survival, as do current cementless cups. Advances in bearing surfaces promise to minimize wear and extend implant longevity. Ceramic on ceramic, metal on highly cross-linked polyethylene, and ceramic on highly cross-linked polyethylene bearing couples offer promise. PMID:23764787

Nelms, Nathaniel J; Lewallen, Laura W; McIntosh, Amy L; Sierra, Rafael J

2013-01-01

122

Metal release and metal allergy after total hip replacement with resurfacing versus conventional hybrid prosthesis  

PubMed Central

Background Metal-on-metal (MOM) total hip arthroplasties were reintroduced because of the problems with osteolysis and aseptic loosening related to polyethylene wear of early metal-on-polyethylene (MOP) arthroplasties. The volumetric wear rate has been greatly reduced with MOM arthroplasties; however, because of nano-size wear particles, the absolute number has been greatly increased. Thus, a source of metal ion exposure with the potential to sensitize patients is present. We hypothesized that higher amounts of wear particles result in increased release of metal ions and ultimately lead to an increased incidence of metal allergy. Methods 52 hips in 52 patients (median age 60 (51–64) years, 30 women) were randomized to either a MOM hip resurfacing system (ReCap) or a standard MOP total hip arthoplasty (Mallory Head/Exeter). Spot urine samples were collected preoperatively, postoperatively, after 3 months, and after 1, 2, and 5 years and tested with inductively coupled plasma-sector field mass spectrometry. After 5 years, hypersensitivity to metals was evaluated by patch testing and lymphocyte transformation assay. In addition, the patients answered a questionnaire about hypersensitivity. Results A statistically significant 10- to 20-fold increase in urinary levels of cobalt and chromium was observed throughout the entire follow-up in the MOM group. The prevalence of metal allergy was similar between groups. Interpretation While we observed significantly increased levels of metal ions in the urine during the entire follow-up period, no difference in prevalence of metal allergy was observed in the MOM group. However, the effect of long-term metal exposure remains uncertain. PMID:24930546

Gustafson, Klas; Jakobsen, Stig S; Lorenzen, Nina D; Thyssen, Jacob P; Johansen, Jeanne D; Bonefeld, Charlotte M; Stilling, Maiken; Baad-Hansen, Thomas; Sřballe, Kjeld

2014-01-01

123

New insights into hard phases of CoCrMo metal-on-metal hip replacements.  

PubMed

The microstructural and mechanical properties of the hard phases in CoCrMo prosthetic alloys in both cast and wrought conditions were examined using transmission electron microscopy and nanoindentation. Besides the known carbides of M(23)C(6)-type (M=Cr, Mo, Co) and M(6)C-type which are formed by either eutectic solidification or precipitation, a new mixed-phase hard constituent has been found in the cast alloys, which is composed of ?100 nm fine grains. The nanosized grains were identified to be mostly of M(23)C(6) type using nano-beam precession electron diffraction, and the chemical composition varied from grain to grain being either Cr- or Co-rich. In contrast, the carbides within the wrought alloy having the same M(23)C(6) structure were homogeneous, which can be attributed to the repeated heating and deformation steps. Nanoindentation measurements showed that the hardness of the hard phase mixture in the cast specimen was ?15.7 GPa, while the M(23)C(6) carbides in the wrought alloy were twice as hard (?30.7 GPa). The origin of the nanostructured hard phase mixture was found to be related to slow cooling during casting. Mixed hard phases were produced at a cooling rate of 0.2 °C/s, whereas single phase carbides were formed at a cooling rate of 50 °C/s. This is consistent with sluggish kinetics and rationalizes different and partly conflicting microstructural results in the literature, and could be a source of variations in the performance of prosthetic devices in-vivo. PMID:22659365

Liao, Y; Pourzal, R; Stemmer, P; Wimmer, M A; Jacobs, J J; Fischer, A; Marks, L D

2012-08-01

124

On the matter of synovial fluid lubrication: implications for Metal-on-Metal hip tribology.  

PubMed

Artificial articular joints present an interesting, and difficult, tribological problem. These bearing contacts undergo complex transient loading and multi axes kinematic cycles, over extremely long periods of time (>10 years). Despite extensive research, wear of the bearing surfaces, particularly metal-metal hips, remains a major problem. Comparatively little is known about the prevailing lubrication mechanism in artificial joints which is a serious gap in our knowledge as this determines film formation and hence wear. In this paper we review the accepted lubrication models for artificial hips and present a new concept to explain film formation with synovial fluid. This model, recently proposed by the authors, suggests that interfacial film formation is determined by rheological changes local to the contact and is driven by aggregation of synovial fluid proteins. The implications of this new mechanism for the tribological performance of new implant designs and the effect of patient synovial fluid properties are discussed. PMID:24462265

Myant, Connor; Cann, Philippa

2014-06-01

125

New Insights into Hard Phases of CoCrMo Metal-on-Metal Hip Replacements  

PubMed Central

The microstructural and mechanical properties of the hard phases in CoCrMo prosthetic alloys in both cast and wrought conditions were examined using transmission electron microscopy and nanoindentation. Besides the known carbides of M23C6-type (M=Cr, Mo, Co) and M6C-type which are formed by either eutectic solidification or precipitation, a new mixed-phase hard constituent has been found in the cast alloys, which is composed of ~100 nm fine grains. The nanosized grains were identified to be mostly of M23C6 type using nano-beam precession electron diffraction, and the chemical composition varied from grain to grain being either Cr- or Co-rich. In contrast, the carbides within the wrought alloy having the same M23C6 structure were homogeneous, which can be attributed to the repeated heating and deformation steps. Nanoindentation measurements showed that the hardness of the hard phase mixture in the cast specimen was ~15.7 GPa, while the M23C6 carbides in the wrought alloy were twice as hard (~30.7 GPa). The origin of the nanostructured hard phase mixture was found to be related to slow cooling during casting. Mixed hard phases were produced at a cooling rate of 0.2 °C/s, whereas single phase carbides were formed at a cooling rate of 50 °C/s. This is consistent with sluggish kinetics and rationalizes different and partly conflicting microstructural results in the literature, and could be a source of variations in the performance of prosthetic devices in-vivo. PMID:22659365

Liao, Y.; Pourzal, R.; Stemmer, P.; Wimmer, M.A.; Jacobs, J.J.; Fischer, A.; Marks, L. D.

2012-01-01

126

In vitro investigation of friction under edge-loading conditions for ceramic-on-ceramic total hip prosthesis.  

PubMed

Edge-loading generates higher wear rates in ceramic-on-ceramic total hip prosthesis (THP). To investigate the friction coefficient (FC) in these conditions, three alumina ceramic (Biolox Forte) 32 mm-diameter components were tested using a hip friction simulator. The cup was positioned with a 75 degrees abduction angle to achieve edge-loading conditions. The motion was first applied along the edge and then across the edge of the cup. First, tests were conducted under lubricated conditions with 25% bovine serum. Next, to simulate an extremely high contact pressure, the tests were run with the addition of a third body alumina ceramic chip inserted between the edge of the cup and the head. Engineering blue was used to analyze the contact area. Reference values were determined using a 0 degrees cup abduction angle. Edge loading was achieved. The FC increased by three- to sixfold when the motion was applied along the edge, and by 70% when the motion was applied across the edge. However, the FC value was still low (about 0.1), which is similar to metal-on-metal THP. With the third body alumina ceramic particle inserted, the FC was 26 times higher than in the ideal conditions and intermittent squeaking occurred. High cup abduction angles may generate edge-loading and an increase in the friction coefficient for ceramic THP. PMID:20135690

Sariali, Elhadi; Stewart, Todd; Jin, Zhongming; Fisher, John

2010-08-01

127

Inertial navigator error models for large heading uncertainty  

Microsoft Academic Search

This paper is concerned with the development of a modified ?-angle error model for a strapdown inertial navigator whose platform azimuth is completely unknown, as would be the case during initial coarse heading alignment. The paper is a review of the author's (1994) previous paper, and provides a framework for developing large azimuth uncertainty error models. It then presents the

Bruno M. Scherzinger

1996-01-01

128

Total School Improvement.  

ERIC Educational Resources Information Center

Three basic activities can infuse classrooms with enjoyment and creativity: use of a total talent portfolio, practice of curriculum compacting, and creation of enrichment clusters. These three activities underlie the Schoolwide Enrichment Model, a blueprint for total school improvement. (SM)

Renzulli, Joseph S.; Purcell, Jeanne H.

1995-01-01

129

Ceramic-on-metal for total hip replacement: mixing and matching can lead to high wear.  

PubMed

Ceramic-on-ceramic and metal-on-metal bearing surfaces are often employed for total hip replacement because of their resistance to wear. However, they have some limits: brittleness is a major concern for ceramic, and ion release is a drawback for metal. To reduce the effect of these limitations, a hybrid coupling of ceramic-on-metal has been proposed. The theoretical advantage of this new coupling might lead orthopedic surgeons to use it indiscriminately. We asked whether the wear rate of this innovative solution was comparable with that of ceramic-on-ceramic, which is considered to be the gold standard for wear resistance. In a hip simulator study, we tested the wear pattern of a hybrid ceramic-on-metal coupling supplied by the same distributor; in particular, three different configurations were tested for 5 million cycles: 36-mm ceramic-on-ceramic, 32-mm and 36-mm ceramic-on-metal. These combinations were gravimetrically and geometrically evaluated. After 5 million cycles, the volumetric loss for the metal acetabular cups (Phi 36-mm) was 20-fold greater than that of the ceramic cups of the same size (Phi 36-mm); a volumetric loss of 4.35 mm(3) and 0.26 mm(3) was observed, respectively, for ceramic-on-metal and ceramic-on-ceramic combinations. Significant statistical differences were observed between all 36-mm different combinations (P < 0.0001). The increased diameter of the 36-mm ceramic-on-metal configuration resulted in a lower volumetric loss compared with that of the 32-mm ceramic-on-metal configuration. Our findings showed an increase in wear for the proposed hybrid specimens with respect to that of the ceramic-on-ceramic ones. This confirms that even in the case of ceramic-on-metal bearings, mixing and matching could not prove effective wear behavior, not even comparable with that of the ceramic-on-ceramic gold standard. PMID:20420614

Affatato, Saverio; Spinelli, Michele; Zavalloni, Mara; Traina, Francesco; Carmignato, Simone; Toni, Aldo

2010-04-01

130

Influence of bone density on total hip resurfacing arthroplasty in patients with osteonecrosis of the femoral head - a radiological analysis.  

PubMed

Osteonecrosis of the femoral head is a more progressive disease for which many patients will eventually require total hip arthroplasty. With the advent of improved metal-on-metal prostheses, total hip resurfacing arthroplasty has emerged as a viable treatment option. However, it remains controversial whether this procedure should be used in patients with osteonecrosis when the femoral resurfacing component is implanted onto non-vital bone. In this study the bone mineral density (BMD) of osteonecrotic femoral heads were compared with the BMD of osteoarthrotic femoral heads. The purpose of this study was to analyse the differences between these two groups to gather information that may be useful in predicting the outcome of total hip resurfacing arthroplasty in cases of severe osteonecrosis of the femoral head. The femoral heads were classified according to the ARCO classification using MRI. For DEXA analysis the femoral heads were subdivided into three regions: the cranial femoral head (R1), the caudal femoral head (R2), and the proximal femoral neck (R3). In R3, BMD in osteonecrotic femoral heads was significantly lower than in those with osteoarthrosis and in R2 it was significantly higher. It can be assumed that a higher BMD in the caudal femoral head (R2) is caused by a "reactive interface" that occurred in this region especially in ARCO IV femoral heads. This fact, the lower BMD in the proximal femoral neck (R3) and the individual expansion of the osteonecrotic region should be considered when planning resurfacing arthroplasty for femoral head necrosis. PMID:18641435

Thorey, Fritz; Reck, Felix; Windhagen, Henning; von Lewinski, Gabriela

2008-01-01

131

Total Baseball Online  

NSDL National Science Digital Library

Total Baseball Online, provided by Tot@l Sports, is a web version of the well known Total Baseball encyclopedia. The highlight of the site is the availability of complete statistics (in a searchable database) of every major league player. Total Baseball not only gives players' raw statistics, but also its own set of derived statistics, including such variables as "Production Plus," "Park Factor," "Runs Created," and "Total Pitcher Index," among many others, all explained at the site and guaranteed to produce arguments among fans. There are also biographies, history, features, records, and a chat room--a veritable mountain of virtual information. At this time, there is no section on the World Series available. Total Baseball Online is only viewable with a browser that supports frames.

132

Updated: April 2013Source: IPEDS: Completions survey, 2010-2011 Grand Total Total Male Total Female  

E-print Network

fCOLLEGEo CHARLESTON Updated: April 2013Source: IPEDS: Completions survey, 2010-2011 Grand Total Total Male Total Female Total Bachelor's Total Bachelor's Male Total Bachelor's Female Total Master's Total Master's Male Total Master's Female College of Charleston 2488 887 1601 2237 803 1434 243 81 162

Kunkle, Tom

133

Total Water Management - slides  

EPA Science Inventory

Total Water Management (TWM) examines urban water systems in an interconnected manner. It encompasses reducing water demands, increasing water recycling and reuse, creating water supply assets from stormwater management, matching water quality to end-use needs, and achieving envi...

134

Total Hip Replacement  

MedlinePLUS

... ankle pump exercises, and early mobilization. Leg-length Inequality Sometimes a er a hip replacement, one leg ... Surgeons (AAOS). To learn more about your orthopaedic health, please visit orthoinfo.org. Total Hip Replacement cont.

135

Tourniquetless Total Knee Arthroplasty  

MedlinePLUS Videos and Cool Tools

Tourniquetless Total Knee Arthroplasty You must have Javascript enabled in your web browser. View Program Transcript Click Here to view the OR-Live, Inc. Privacy Policy and Legal Notice © 2010 OR- ...

136

Total Solar Eclipse Animation  

NSDL National Science Digital Library

Solar eclipses result from the alignment of the Sun, Moon, and Earth. Total solar eclipses, in which the Sun is completely blocked by the Moon, are a spectacular and rare sight to witness. This animation, adapted from a NOVA television broadcast, shows a simulated total eclipse and explains some of the features that can be seen. The clip is one minute thirteen seconds in length.

137

Total Internal Reflection  

NSDL National Science Digital Library

In this activity, learners use a laser pointer, empty soda bottle, rubber plug and water to demonstrate total internal reflection. Use this simple activity as a demonstration or group activity to explore reflection, refraction, fiber optics, and Snell's Law. This resource contains background information about total internal reflection, the equation for Snell's Law, and refractive indexes as well as links to articles about reflection and refraction of light.

2012-12-18

138

Total Energy Monitor  

SciTech Connect

The total energy monitor (TE) is a thermal sensor that determines the total energy of each FEL pulse based on the temperature rise induced in a silicon wafer upon absorption of the FEL. The TE provides a destructive measurement of the FEL pulse energy in real-time on a pulse-by-pulse basis. As a thermal detector, the TE is expected to suffer least from ultra-fast non-linear effects and to be easy to calibrate. It will therefore primarily be used to cross-calibrate other detectors such as the Gas Detector or the Direct Imager during LCLS commissioning. This document describes the design of the TE and summarizes the considerations and calculations that have led to it. This document summarizes the physics behind the operation of the Total Energy Monitor at LCLS and derives associated engineering specifications.

Friedrich, S

2008-08-11

139

Total wrist arthroplasty.  

PubMed

This article reviews the history of total wrist arthroplasty as a treatment option for painful, nonfunctional wrists in disease states. Technologic advances in materials, wear properties, and manufacturing now account for increased implant longevity. They may also improve total wrist replacement design, survival, and hence patient function. Also, alternative surgical treatments such as distal radius hemiarthroplasty may serve as a treatment option for patients with higher activity levels and diffuse arthritis. With careful patient selection, soft tissue considerations, and novel implant designs, TWA may become a viable treatment staple for patients with functional wrist disability. PMID:23101610

McBeath, Rowena; Osterman, A Lee

2012-11-01

140

Total synthesis of (-)-dolastatrienol.  

PubMed

The first asymmetric total synthesis of the tricyclic diterpenoid natural product (-)-dolastatrienol has been accomplished using a rhodium(II)-catalyzed carbene cyclization cycloaddition cascade reaction as the key step to construct the [5.4.0]carbobicyclic core. An intramolecular Heck reaction furnished the tricyclic skeleton and a challenging methylenation completed the synthesis of the target. PMID:25556852

Leung, Lai To; Chiu, Pauline

2015-04-01

141

A Total Solar Eclipse  

NSDL National Science Digital Library

The representation depicts a total solar eclipse with a static diagram showing the moon positioned between the sun and Earth. The point where the shadow cone reaches the Earth is labeled with an arrow stating it as the "eclipse path." The umbra and penumbra are also labeled.

142

Total Quality Management  

NSDL National Science Digital Library

Total Quality Management is a lesson plan which provides students with a broad introduction to the quality approaches used in manufacturing. After completing this module, students should be able to apply various quality improvement techniques during a simulated manufacturing process. Note: This module is part of a modularized manufacturing technology curriculum created by the PSCME, found at www.pscme.org/educators.html.

Imre, John

143

TOTAL CHARGE PAY CODEDIAGNOSIS  

E-print Network

16.* PLACE OF SERVICE TOTAL CHARGE PAY CODEDIAGNOSIS CODE -- IMPORTANT -- Please read and follow NAME 20. I AUTHORIZE THE RELEASE TO ANTHEM BLUE CROSS AND BLUE SHIELD OF ANY INFORMATION NECESSARY/INPATIENT (BED PATIENT) . . . . . . . . . . . . . .3 NURSING HOME (SKILLED NURSING FACILITY) . . . . .4 HOSPITAL

Myers, Lawrence C.

144

Total Quality Management Simplified.  

ERIC Educational Resources Information Center

Maintains that Total Quality Management (TQM) is one method that helps to monitor and improve the quality of child care. Lists four steps for a child-care center to design and implement its own TQM program. Suggests that quality assurance in child-care settings is an ongoing process, and that TQM programs help in providing consistent, high-quality…

Arias, Pam

1995-01-01

145

Total Quality Management Seminar.  

ERIC Educational Resources Information Center

This booklet is one of six texts from a workplace literacy curriculum designed to assist learners in facing the increased demands of the workplace. The booklet contains seven sections that cover the following topics: (1) meaning of total quality management (TQM); (2) the customer; (3) the organization's culture; (4) comparison of management…

Massachusetts Career Development Inst., Springfield.

146

TOTAL DIET STUDY  

EPA Science Inventory

The Total Diet Study (TDS), sometimes called the Market Basket Study, is an ongoing FDA program that determines levels of various pesticide residues, contaminants, and nutrients in foods, for the purpose of estimating intakes of these substances in representative diets of specifi...

147

Total Synthesis of (?)-Mucocin  

PubMed Central

An enantioselective total synthesis of (?)-mucocin has been completed. A combination of asymmetric glycolate aldol additions and ring closing metathesis reactions were exploited to construct the C18-C34 and C7-C17 fragments. A selective cross metathesis reaction was employed as the key step to couple two complex fragments. PMID:16706528

Crimmins, Michael T.; Zhang, Yan; Diaz, Frank A.

2008-01-01

148

Total synthesis of (-)-mucocin.  

PubMed

[reaction: see text] An enantioselective total synthesis of (-)-mucocin has been completed. A combination of asymmetric glycolate aldol additions and ring closing metathesis reactions were exploited to construct the C18-C34 and C7-C17 fragments. A selective cross-metathesis reaction was employed as the key step to couple two complex fragments. PMID:16706528

Crimmins, Michael T; Zhang, Yan; Diaz, Frank A

2006-05-25

149

Total Synthesis of Kopsinine  

PubMed Central

The use of a powerful intramolecular [4 + 2]/[3 + 2] cycloaddition cascade of an 1,3,4-oxadiazole in the divergent total synthesis of kopsinine (1), featuring an additional unique SmI2-promoted transannular cyclization reaction for formation of the bicyclo[2.2.2]octane central to its hexacyclic ring system, is detailed. PMID:23391149

Xie, Jian; Wolfe, Amanda L.; Boger, Dale L.

2013-01-01

150

Total synthesis of kopsinine.  

PubMed

The use of a powerful intramolecular [4 + 2]/[3 + 2] cycloaddition cascade of an 1,3,4-oxadiazole in the divergent total synthesis of kopsinine (1), featuring an additional unique SmI(2)-promoted transannular cyclization reaction for formation of the bicyclo[2.2.2]octane central to its hexacyclic ring system, is detailed. PMID:23391149

Xie, Jian; Wolfe, Amanda L; Boger, Dale L

2013-02-15

151

Total Synthesis of Jiadifenolide**  

PubMed Central

As a potent neurotrophic agent, the sesquiterpenoid jiadifenolide represents a valuable small-molecule lead for the potential therapeutic treatment of neurodegenerative diseases. A stereocontrolled total synthesis of this densely functionalized natural product is reported, central to which is an adventurous samarium-mediated cyclization reaction to establish the tricyclic core and the adjacent C5 and C6 quaternary stereocenters. PMID:24861364

Paterson, Ian; Xuan, Mengyang; Dalby, Stephen M

2014-01-01

152

Total Precipitable Water  

SciTech Connect

The simulation was performed on 64K cores of Intrepid, running at 0.25 simulated-years-per-day and taking 25 million core-hours. This is the first simulation using both the CAM5 physics and the highly scalable spectral element dynamical core. The animation of Total Precipitable Water clearly shows hurricanes developing in the Atlantic and Pacific.

None

2012-01-01

153

Laparoscopic total abdominal colectomy  

Microsoft Academic Search

The aim of this study was to prospectively assess the impact of laparoscopy upon the outcome of total abdominal colectomy (TAC). Specifically, patients underwent standard laparotomy with TAC and ileoproctostomy (TAC + IP), TAC and ileoanal reservoir (TAC + IAR), laparoscopically assisted TAC + IP (L-TAC + IP), or laparoscopically assisted TAC + IAR (L-TAC + IAR). Parameters studied included

Steven D. Wexner; Olaf B. Johansen; Juan J. Nogueras; David G. Jagelman

1992-01-01

154

Total synthesis of gracilamine.  

PubMed

The total synthesis of gracilamine, a pentacyclic Amaryllidaceae alkaloid, was achieved from simple building blocks. The synthesis features a mild photo-Nazarov reaction, intramolecular 1,4-addition, and an intramolecular Mannich reaction. This approach not only confirms the C6 stereochemistry of natural gracilamine, and also provides a novel solution to prepare its derivatives and structurally related natural products. PMID:25044967

Shi, Yingbo; Yang, Baochao; Cai, Shujun; Gao, Shuanhu

2014-09-01

155

CSF total protein  

MedlinePLUS

CSF total protein is a test to determine the amount of protein in your spinal fluid, also called cerebrospinal fluid (CSF). ... The normal protein range varies from lab to lab, but is typically about 15 to 60 mg/dL. Note: mg/dL = ...

156

Total Sustainability Humber College  

E-print Network

1 Total Sustainability Management Humber College November, 2012 SUSTAINABILITY SYMPOSIUM Green An Impending Global Disaster #12;3 Sustainability is NOT Climate Remediation #12;Our Premises "We cannot, you cannot improve it" (Lord Kelvin) "First rule of sustainability is to align with natural forces

Thompson, Michael

157

Total Technology Immersion  

ERIC Educational Resources Information Center

Total technology immersion doesn't happen overnight, but with vision and determination, transformation can take hold and start to grow. Floydada Independent School District (FISD), winner of the 2010 Sylvia Charp Award for District Innovation in Technology, is a great example of what a district can achieve when starting with a modest tech…

Vaughn, Sandy

2010-01-01

158

Total Productive Maintenance  

NSDL National Science Digital Library

Created by Kaye Krueger of Wisconsin Online Resource Center, this presentation allows user to read about how total productive maintenance can prevent breakdowns, defects, and a variety of other losses. This is a nice brief introduction to this important topic in manufacturing engineering.

Krueger, Kaye

159

Total Water Management - Report  

EPA Science Inventory

There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current operations put different stresses on the environment and urban infrastructure. Total Water Management (TWM) is an approac...

160

Total fatigue curve  

SciTech Connect

The fatigue failure mechanisms operative on different segments of the total fatigue curve are discussed. The need for experimental determination of this curve is emphasized; once known, this curve will make possible a deeper insight into the transitional zones associated with a change in the cumulative fatigue damage mechanism.

Sosnovskii, L.A.; Makhutov, N.A. [A.A. Blagonravov Inst. of Machine Engineering, Moscow (Russian Federation)

1995-11-01

161

Early failure of articular surface replacement XL total hip arthroplasty.  

PubMed

The ASR (articular surface replacement) XL (DePuy, Warsaw, Ind) metal-on-metal hip arthroplasty offers the advantage of stability and increased motion. However, an alarming number of early failures prompted the evaluation of patients treated with this system. A prospective study of patients who underwent arthroplasty with the ASR XL system was performed. Patients with 2-year follow-up or any revision were included. Failure rates, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and radiographs were evaluated. Ninety-five patients (105 hips) were included. There were 16 revisions. Thirteen (12%) were aseptic acetabular failures. Eight were revised for aseptic loosening; 4, for metallosis; 1, for malposition; 2, for infection; and 1, for periprosthetic fracture. Mean time to revision was 1.6 years (0.18-3.4 years). The ASR XL with a revision rate of 12% is the second reported 1 piece metal-on-metal system with a significant failure rate at early follow-up. This particular class of implants has inherent design flaws that lead to early failure. PMID:21550764

Steele, Garen D; Fehring, Thomas K; Odum, Susan M; Dennos, Anne C; Nadaud, Matthew C

2011-09-01

162

Total synthesis of clostrubin  

PubMed Central

Clostrubin is a potent antibiotic against methicillin- and vancomycin-resistant bacteria that was isolated from a strictly anaerobic bacterium Clostridium beijerinckii in 2014. This polyphenol possesses a fully substituted arene moiety on its pentacyclic scaffold, which poses a considerable challenge for chemical synthesis. Here we report the first total synthesis of clostrubin in nine steps (the longest linear sequence). A desymmetrization strategy is exploited based on the inherent structural feature of the natural product. Barton–Kellogg olefination forges the two segments together to form a tetrasubstituted alkene. A photo-induced 6? electrocyclization followed by spontaneous aromatization constructs the hexasubstituted B ring at a late stage. In total, 200?mg of clostrubin are delivered through this approach. PMID:25759087

Yang, Ming; Li, Jian; Li, Ang

2015-01-01

163

Totally parallel multilevel algorithms  

NASA Technical Reports Server (NTRS)

Four totally parallel algorithms for the solution of a sparse linear system have common characteristics which become quite apparent when they are implemented on a highly parallel hypercube such as the CM2. These four algorithms are Parallel Superconvergent Multigrid (PSMG) of Frederickson and McBryan, Robust Multigrid (RMG) of Hackbusch, the FFT based Spectral Algorithm, and Parallel Cyclic Reduction. In fact, all four can be formulated as particular cases of the same totally parallel multilevel algorithm, which are referred to as TPMA. In certain cases the spectral radius of TPMA is zero, and it is recognized to be a direct algorithm. In many other cases the spectral radius, although not zero, is small enough that a single iteration per timestep keeps the local error within the required tolerance.

Frederickson, Paul O.

1988-01-01

164

Inverse Total Variation Flow  

Microsoft Academic Search

In this paper we analyze iterative regularization with the Breg- man distance of the total variation semi norm. Moreover, we prove existence of a solution of the corresponding flow equation as introduced in (8) in a func- tional analytical setting using methods from convex analysis. The results are generalized to variational denoising methods with Lp-norm fit-to-data terms and Bregman distance

M. Burger; K. Frick; S. Osher; O. Scherzer

2007-01-01

165

Total systems design approach  

Microsoft Academic Search

Dudley Products, Inc., an 85,327 ft² facility, consists of 33,305 ft² of offices and laboratories. It has 30 ft ceilings in the spacious lobby, and a 52,022 ft² manufacturing facility with 22 ft ceilings. These facilities produce a total heated and cooled volumetric space of approximately 1.5 million cubic feet. This article describes a project to produce a guaranteed, performance-based

Boody

1997-01-01

166

Total variation blind deconvolution  

Microsoft Academic Search

We present a blind deconvolution algorithm based on the total variational (TV) minimization method proposed by Acar and Vogel (1994). The motivation for regularizing with the TV norm is that it is extremely effective for recovering edges of images as well as some blurring functions, e.g., motion blur and out-of-focus blur. An alternating minimization (AM) implicit iterative scheme is devised

Tony F. Chan; Chiu-Kwong Wong

1998-01-01

167

Total synthesis of (-)-borrelidin.  

PubMed

The total synthesis of borrelidin has been achieved. The best feature of our synthetic route is SmI(2)-mediated intramolecular Reformatsky-type reaction for macrocyclization after esterification between two segments. The two key segments were synthesized through chelation-controlled carbotitanation, chelation-controlled hydrogenation, stereoselective Reformatsky reaction, and MgBr(2).Et(2)O-mediated chelation-controlled allylation. [reaction: see text] PMID:15151434

Nagamitsu, Tohru; Takano, Daisuke; Fukuda, Takeo; Otoguro, Kazuhiko; Kuwajima, Isao; Harigaya, Yoshihiro; Omura, Satoshi

2004-05-27

168

Totally laparoscopic feeding jejunostomy  

Microsoft Academic Search

  Background: A feeding jejunostomy should be used for nutritional support in a small subset of patients. Minimal-access approaches\\u000a for the placement of jejunal tubes have been described, but they often require special equipment not common to all operating\\u000a theaters. We describe a technique of totally laparoscopic jejunostomy tube (LJT) placement using equipment found in most operating\\u000a theaters. Methods: Thirty-five patients

J. W. Allen; A. Ali; J. Wo; J. M. Bumpous; R. N. Cacchione

2002-01-01

169

Total organic carbon analyzer  

Microsoft Academic Search

The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The

Richard G. Godec; Paul P. Kosenka; Brian D. Smith; Richard S. Hutte; Johanna V. Webb; Richard L. Sauer

1991-01-01

170

Physician Update: Total Health  

PubMed Central

As an integrated prepaid health care system, Kaiser Permanente (KP) is in a unique position to demonstrate that affordability in health care can be achieved by disease prevention. During the past decade, KP has significantly improved the quality care outcomes of its members with preventable diseases. However, because of an increase in the incidence of preventable disease, and the potential long-term and short-term costs associated with the treatment of preventable disease, KP has developed a new strategy called Total Health to meet the current and future needs of its patients. Total Health means healthy people in healthy communities. KP’s strategic vision is to be a leader in Total Health by making lives better. KP hopes to make lives better by 1) measuring vital signs of health, 2) promoting healthy behaviors, 3) monitoring disease incidence, 4) spreading leading practices, and 5) creating healthy environments with our community partners. Best practices, spread to the communities we serve, will make health care more affordable, prevent preventable diseases, and save lives. PMID:24694316

Tuso, Phillip

2014-01-01

171

New concept for total wrist replacement.  

PubMed

Wrist prostheses have never achieved the sort of clinical outcomes found with those of hips and knees. We have developed a novel uncemented modular wrist prosthesis with screw fixation, metal-on-metal coupling, and ball-and-socket articulation. Eight patients admitted for wrist arthrodesis to treat primary or secondary osteoarthritis (not rheumatoid) were operated on. The prosthesis reduced the amount of bone removed and spared the distal radioulnar joint. After 7 to 9 years we found that the fixed centre of the ball-and-socket articulation provided good stability and mobility, and relief of pain and grip strength were satisfactory. We saw no luxations, metacarpal fractures or cut-outs, or mechanical failures of the implants. Two distal screws loosened (revised with new distal screws), and one early inflammation and one late infection occurred (revised to arthrodesis). We propose modifications to the implant with reduction in the diameter of the screws and the height of the threads, and rounding of the distal tip. The technique should include release of the third carpometacarpal joint, alignment of the capitate and the third metacarpal, and arthrodesis of the joint with bone chips. PMID:21682612

Reigstad, Astor; Reigstad, Ole; Grimsgaard, Christian; Rřkkum, Magne

2011-06-01

172

The clinical and radiological outcomes of hip resurfacing versus total hip arthroplasty: a meta-analysis and systematic review  

PubMed Central

Background and purpose Hip resurfacing (HRS) procedures have gained increasing popularity for younger, higher-demand patients with degenerative hip pathologies. However, with concerns regarding revision rates and possible adverse metal hypersensitivity reactions with metal-on-metal articulations, some authors have questioned the hypothesized superiority of hip resurfacing over total hip arthroplasty (THA). In this meta-analysis, we compared the clinical and radiological outcomes and complication rates of these 2 procedures. Methods A systematic review was undertaken of all published (Medline, CINAHL, AMED, EMBASE) and unpublished or gray literature research databases up to January 2010. Clinical and radiological outcomes as well as complications of HRS were compared to those of THA using risk ratio, mean difference, and standardized mean difference statistics. Studies were critically appraised using the CASP appraisal tool. Results 46 studies were identified from 1,124 citations. These included 3,799 HRSs and 3,282 THAs. On meta-analysis, functional outcomes for subjects following HRS were better than or the same as for subjects with a THA, but there were statistically significantly greater incidences of heterotopic ossification, aseptic loosening, and revision surgery with HRS compared to THA. The evidence base showed a number of methodological inadequacies such as the limited use of power calculations and poor or absent blinding of both patients and assessors, possibly giving rise to assessor bias. Interpretation On the basis of the current evidence base, HRS may have better functional outcomes than THA, but the increased risks of heterotopic ossification, aseptic loosening, and revision surgery following HRS indicate that THA is superior in terms of implant survival. PMID:21067432

2010-01-01

173

Total synthesis of borrelidin.  

PubMed

The total synthesis of borrelidin has been achieved. The best feature of our synthetic route is macrocyclization at C11-C12 for the construction of an 18-membered ring after esterification between two segments. A detailed examination of the macrocyclization led us to the samarium(II) iodide-mediated intramolecular Reformatsky-type reaction as the most efficient synthetic approach. The two key segments were synthesized through regioselective methylation, directed hydrogenation, stereoselective Reformatsky-type reaction, and MgBr2.Et2O-mediated chelation-controlled allylation. PMID:17355148

Nagamitsu, Tohru; Takano, Daisuke; Marumoto, Kaori; Fukuda, Takeo; Furuya, Kentaro; Otoguro, Kazuhiko; Takeda, Kazuyoshi; Kuwajima, Isao; Harigaya, Yoshihiro; Omura, Satoshi

2007-04-13

174

Total quality assurance  

NASA Astrophysics Data System (ADS)

Quality, cost, and schedule are three factors affecting the competitiveness of a company; they require balancing so that products of acceptable quality are delivered, on time and at a competitive cost. Quality costs comprise investment in quality maintenance and failure costs which arise from failure to maintain standards. The basic principle for achieving the required quality at minimum cost is that of prevention of failures, etc., through production control, attention to manufacturing practices, and appropriate management and training. Total quality control involves attention to the product throughout its life cycle, including in-service performance evaluation, servicing, and maintenance.

Louzon, E.

1989-12-01

175

TOTAL user manual  

NASA Technical Reports Server (NTRS)

Semi-Markov models can be used to analyze the reliability of virtually any fault-tolerant system. However, the process of delineating all of the states and transitions in the model of a complex system can be devastatingly tedious and error-prone. Even with tools such as the Abstract Semi-Markov Specification Interface to the SURE Tool (ASSIST), the user must describe a system by specifying the rules governing the behavior of the system in order to generate the model. With the Table Oriented Translator to the ASSIST Language (TOTAL), the user can specify the components of a typical system and their attributes in the form of a table. The conditions that lead to system failure are also listed in a tabular form. The user can also abstractly specify dependencies with causes and effects. The level of information required is appropriate for system designers with little or no background in the details of reliability calculations. A menu-driven interface guides the user through the system description process, and the program updates the tables as new information is entered. The TOTAL program automatically generates an ASSIST input description to match the system description.

Johnson, Sally C.; Boerschlein, David P.

1994-01-01

176

Cervical total disc arthroplasty.  

PubMed

Symptomatic adjacent segment degeneration of the cervical spine remains problematic for patients and surgeons alike. Despite advances in surgical techniques and instrumentation, the solution remains elusive. Spurred by the success of total joint arthroplasty in hips and knees, surgeons and industry have turned to motion preservation devices in the cervical spine. By preserving motion at the diseased level, the hope is that adjacent segment degeneration can be prevented. Multiple cervical disc arthroplasty devices have come onto the market and completed Food and Drug Administration Investigational Device Exemption trials. Though some of the early results demonstrate equivalency of arthroplasty to fusion, compelling evidence of benefits in terms of symptomatic adjacent segment degeneration are lacking. In addition, non-industry-sponsored studies indicate that these devices are equivalent to fusion in terms of adjacent segment degeneration. Longer-term studies will eventually provide the definitive answer. PMID:24353955

Basho, Rahul; Hood, Kenneth A

2012-06-01

177

Total Productive Maintenance (TPM)  

NSDL National Science Digital Library

It can be considered as the medical science of machines. Total Productive Maintenance (TPM) is a maintenance program which involves a newly defined concept for maintaining plants and equipment. The goal of the TPM program is to markedly increase production while, at the same time, increasing employee morale and job satisfaction.TPM brings maintenance into focus as a necessary and vitally important part of the business. It is no longer regarded as a non-profit activity. Down time for maintenance is scheduled as a part of the manufacturing day and, in some cases, as an integral part of the manufacturing process. The goal is to hold emergency and unscheduled maintenance to a minimum.

178

A INDIVIDUAL Ticket Total $ B AFFILIATE MEMBERSHIP Total (page 15)  

E-print Network

A INDIVIDUAL Ticket Total $ B AFFILIATE MEMBERSHIP Total (page 15) $ Add Processing Fee $ 5.00 TOTAL Payment Enclosed $ Deduct 10% if 5 or more different performances are purchased. A INDIVIDUAL 16.) Performance Date/Time Price per Ticket Qty. Total For Box Office use only Transfer INDIVIDUAL

Roy, Subrata

179

Total Staff -Durham & UNHM -Fall 2005 Total 3506 %  

E-print Network

Total Staff - Durham & UNHM - Fall 2005 Total 3506 % men 1440 41.1 women 2066 58.9 full-time 1702 48.5 part-time 1804 51.5 International 60 1.7 Total Minority Staff - Durham & UNHM - Fall 2005 % Total 82 2.3 (of total) men 30 36.6 women 52 63.4 native am/alaskan 5 6.1 black, non-hispanic 27 32

New Hampshire, University of

180

Mujeres Hombres Total Hombres Total 11 15 26 13 22  

E-print Network

Mujeres Hombres Total Hombres Total 11 15 26 13 22 24 11 35 5 23 28 5 33 2 16 1 1 2 1 2 64 32 96 21 Programas de Voluntariado Local Total Humanidades Ciencias Experimentales Nº de voluntarios/as: estudios por programas y totales. Ciencias Sociales y Jurídicas TOTAL VOLUNTARIADO LOCAL Enseñanzas Técnicas Ciencias de

Autonoma de Madrid, Universidad

181

TOTAL POSITIVITY: TESTS AND PARAMETRIZATIONS  

E-print Network

TOTAL POSITIVITY: TESTS AND PARAMETRIZATIONS SERGEY FOMIN AND ANDREI ZELEVINSKY Introduction A matrix is totally positive (resp. totally nonnegative) if all its minors are pos­ itive (resp (in particular, an n \\Theta n totally positive matrix x has n distinct positive eigenvalues). Earlier

Fomin, Sergey

182

Determination of Total Petroleum Hydrocarbons (TPH) Using Total Carbon Analysis  

SciTech Connect

Several methods have been proposed to replace the Freon(TM)-extraction method to determine total petroleum hydrocarbon (TPH) content. For reasons of cost, sensitivity, precision, or simplicity, none of the replacement methods are feasible for analysis of radioactive samples at our facility. We have developed a method to measure total petroleum hydrocarbon content in aqueous sample matrixes using total organic carbon (total carbon) determination. The total carbon content (TC1) of the sample is measured using a total organic carbon analyzer. The sample is then contacted with a small volume of non-pokar solvent to extract the total petroleum hydrocarbons. The total carbon content of the resultant aqueous phase of the extracted sample (TC2) is measured. Total petroleum hydrocarbon content is calculated (TPH = TC1-TC2). The resultant data are consistent with results obtained using Freon(TM) extraction followed by infrared absorbance.

Ekechukwu, A.A.

2002-05-10

183

Unlinked total elbow arthroplasty.  

PubMed

For more than 60 years, total elbow arthroplasty (TEA) has been successfully used to treat a variety of elbow conditions. Although first designed to treat older patients with rheumatoid arthritis, the indications have expanded to include younger, higher-demand patients with a broad range of elbow pathology. Two groups of TEA currently exist. The first group includes linked or semiconstrained elbows with a mechanical connection between the humeral and ulnar components that prevents disassociation. These implants do not rely on muscular or ligamentous tissues for stability. The second group includes unlinked implants that have no physical connection between the humeral and ulnar components. They rely on bearing surface architecture as well as soft-tissue integrity for elbow stability. Critical to the success of unlinked implants is a thorough preoperative evaluation of elbow stability, including bone stock, collateral ligament integrity, and periarticular muscle function. Unlinked implants should apply less strain to the bone-cement-implant interfaces, which may theoretically decrease rates of bearing wear and aseptic loosening. For this reason, some surgeons prefer unlinked implants for younger, higher-demand patients. To date, unlinked implants have not been clinically shown to improve survivorship compared with linked devices. No prospective randomized trials comparing linked and unlinked TEAs are currently available. Historically, unlinked implants have had higher revision rates, mostly caused by instability and early design flaws. More recent series have shown no significant differences in outcomes compared with linked devices. Unlinked TEA provides reliable pain relief and improved range of motion for patients with a variety of elbow disorders. Diligent patient selection and careful surgical technique are of utmost importance when considering an unlinked TEA as a treatment option. The recent development of convertible implants now allows surgeons to make intraoperative decisions regarding elbow stability and convert to a linked implant without revising the stems. PMID:25745909

Marsh, Jonathan P; King, Graham J W

2015-01-01

184

Total Laparoscopic Pancreaticoduodenectomy  

PubMed Central

Introduction: Total laparoscopic pancreaticoduodenectomy (TLPD) remains one of the most advanced laparoscopic procedures. Owing to the evolution in laparoscopic technology and instrumentation within the past decade, laparoscopic pancreaticoduodenectomy is beginning to gain wider acceptance. Methods: Data were collected for all patients who underwent a TLPD at our institution. Preoperative evaluation consisted of computed tomography scan with pancreatic protocol and selective use of magnetic resonance imaging and/or endoscopic ultrasonography. The TLPD was done with 6 ports on 3 patients and 5 ports in 2 patients and included a celiac, periportal, peripancreatic, and periduodenal lymphadenectomy. Pancreatic stents were used in all 5 cases, and intestinal continuity was re-established by intracorporeal anastomoses. Results: Five patients underwent a TLPD for suspicion of a periampullary tumor. There were 3 women and 2 men with a mean age of 60 years and a mean body mass index of 32.8. Intraoperatively, the mean operative time was 9 hours 48 minutes, with a mean blood loss of 136 mL. Postoperatively, there were no complications and a mean length of stay of 6.6 days. There was no lymph node involvement in 4 out of 5 specimens. The pathological results included intraductal papillary mucinous neoplasm in 2 patients, pancreatic adenocarcinoma in 1 patient (R0 resection), benign 4-cm periampullary adenoma in 1 patient, and a somatostatin neuroendocrine carcinoma in 1 patient (R0, N1). Conclusion: TLPD is a viable alternative to the standard Whipple procedure. Our early experience suggests decreased length of stay, quicker recovery, and improved quality of life. Complication rates appear to be improved or equivalent. PMID:23925010

Kamyab, Armin

2013-01-01

185

Mujeres Hombres Total Hombres Total 16 5 21 0 10  

E-print Network

Mujeres Hombres Total Hombres Total 16 5 21 0 10 15 11 26 2 15 31 6 37 1 24 7 2 9 1 8 13 3 16 2 14-Voluntariado Local Curso 2010-2011 NÂş de voluntarios/as: mujeres, hombres y totales por programas. Programas de Voluntariado Total voluntarios/as Altas curso 10/11 Mujeres Ambiental 10 Apoyo a mayores 13 AnimaciĂłn en

Autonoma de Madrid, Universidad

186

Recommended Amounts of Total grains  

Cancer.gov

Recommended Amounts of Total grains Table B8. Total grains: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake above

187

Recommended Amounts of Total seafood  

Cancer.gov

Recommended Amounts of Total seafood Table B12. Total seafood: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake

188

Total Energy Production State Rankings  

NSDL National Science Digital Library

Ranks all 50 states in total energy production. Includes links to tables which rank production of crude oil, natural gas, coal, and electricity; crude oil emissions; total energy consumption; and energy prices.

Energy Information Administration

189

Recommended Amounts of Total dairy  

Cancer.gov

Recommended Amounts of Total dairy Table B15. Total dairy: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake above

190

Full Abstraction, Totality and PCF   

E-print Network

Inspired by a question of Riecke, we consider the interaction of totality and full abstraction, asking whether full abstraction holds for Scott’s model of cpos and continuous functions if one restricts to total programs ...

Plotkin, Gordon

2003-11-06

191

Recommended Amounts of Total fruits  

Cancer.gov

Recommended Amounts of Total fruits Table B1. Total fruits: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake above

192

Total correlations and mutual information  

E-print Network

In quantum information theory it is generally accepted that quantum mutual information is an information-theoretic measure of total correlations of a bipartite quantum state. We argue that there exist quantum states for which quantum mutual information cannot be considered as a measure of total correlations. Moreover, for these states we propose a different way of quantifying total correlations.

Zbigniew Walczak

2012-11-15

193

Total positivity, Grassmannians, and networks  

Microsoft Academic Search

The aim of this paper is to discuss a relationship between total positivity and planar directed networks. We show that the inverse boundary problem for these networks is naturally linked with the study of the totally nonnegative Grassmannian. We investigate its cell decomposition, where the cells are the totally nonnegative parts of the matroid strata. The boundary measurements of networks

Alexander Postnikov

2006-01-01

194

MUJERES TOTAL BIOLOGIA 14 28  

E-print Network

JURIDICA 0 5 5 15 INGENIERIA INFORMATICA 0 3 TECNOLOGIA ELECTRONICA Y DE LAS COMUNICACIONES 2 6 2 9 MEDICINA 26 37 MEDICINA PREVENTIVA Y SALUD PUBLICA Y MICROBIOLOGIA 6 11 OBSTETRICIA Y GINECOLOGIA 3 5 DERECHO TOTAL ESCUELA POLITĂ?CNICA SUPERIOR TOTAL DERECHO CENTRO DEPARTAMENTO NÂş DE TESIS TOTAL MEDICINA

Autonoma de Madrid, Universidad

195

78 FR 24426 - Orthopaedic and Rehabilitation Devices Panel of the Medical Devices Advisory Committee; Notice of...  

Federal Register 2010, 2011, 2012, 2013, 2014

...by SpinalMotion. The Kineflex/C is a metal-on-metal (cobalt chrome molybdenum alloy) cervical total disc replacement device...The Kineflex Lumbar Artificial Disc is a metal-on-metal (cobalt chrome molybdenum alloy) lumbar total disc replacement...

2013-04-25

196

Corrosion at the Head-Neck Taper as a Cause for Adverse Local Tissue Reactions After Total Hip Arthroplasty  

PubMed Central

Background: Corrosion at the modular head-neck junction of the femoral component in total hip arthroplasty has been identified as a potential concern, although symptomatic adverse local tissue reactions secondary to corrosion have rarely been described. Methods: We retrospectively reviewed the records of ten patients with a metal-on-polyethylene total hip prosthesis, from three different manufacturers, who underwent revision surgery for corrosion at the modular head-neck junction. Results: All patients presented with pain or swelling around the hip, and two patients presented with recurrent instability. Serum cobalt levels were elevated prior to the revision arthroplasty and were typically more elevated than were serum chromium levels. Surgical findings included large soft-tissue masses and surrounding tissue damage with visible corrosion at the femoral head-neck junction; the two patients who presented with instability had severe damage to the hip abductor musculature. Pathology specimens consistently demonstrated areas of tissue necrosis. The patients were treated with debridement and a femoral head and liner exchange, with use of a ceramic femoral head with a titanium sleeve in eight cases. The mean Harris hip score improved from 58.1 points preoperatively to 89.7 points at a mean of 13.0 months after the revision surgery (p = 0.01). Repeat serum cobalt levels, measured in six patients at a mean of 8.0 months following revision, decreased to a mean of 1.61 ng/mL, and chromium levels were similar to prerevision levels. One patient with moderate hip abductor muscle necrosis developed recurrent instability after revision and required a second revision arthroplasty. Conclusions: Adverse local tissue reactions can occur in patients with a metal-on-polyethylene bearing secondary to corrosion at the modular femoral head-neck taper, and their presentation is similar to the adverse local tissue reactions seen in patients with a metal-on-metal bearing. Elevated serum metal levels, particularly a differential elevation of serum cobalt levels with respect to chromium levels, can be helpful in establishing this diagnosis. Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence. PMID:23289127

John Cooper, H.; Della Valle, Craig J.; Berger, Richard A.; Tetreault, Matthew; Paprosky, Wayne G.; Sporer, Scott M.; Jacobs, Joshua J.

2012-01-01

197

Dislocation after total knee arthroplasty.  

PubMed

Two cases of dislocation of total knee arthroplasty presented to us within the same week. The first patient is a 71-year-old woman who underwent bilateral primary total knee arthroplasty. The left knee dislocated three weeks after the surgery. Due to failure of conservative measures, she underwent revision total knee arthroplasty. The other patient is a 72-year-old woman presenting ten years after primary total knee arthroplasty, with a traumatic dislocation of the knee joint. She was treated as an outpatient with closed manipulative reduction. PMID:17453086

Wazir, N N; Shan, Y; Mukundala, V V; Gunalan, R

2007-05-01

198

Usual Intake of Total grains  

Cancer.gov

Usual Intake of Total grains Table A17. Total grains: Means, percentiles and standard errors of usual intake, 2007-2010 Age (Years) N1 oz equivalents3 Mean (SE)2 5% (SE) 10% (SE) 25% (SE) 50% (SE) 75% (SE) 90% (SE) 95% (SE) Males 1-3 774 4.1 (0.10) 2.2

199

The total charm cross section  

SciTech Connect

We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that the uncertainty on the total charm cross section is difficult to quantify.

Vogt, R

2007-09-14

200

Total Synthesis of Bryostatin 9  

PubMed Central

The total synthesis of bryostatin 9 was accomplished using a uniquely step economical and convergent Prins-driven macrocyclization strategy. At 25 linear and 42 total steps, this is currently the most concise and convergent (5 steps post fragment coupling) synthesis of a potent bryostatin. PMID:21618969

Wender, Paul A.; Schrier, Adam J.

2011-01-01

201

The tropical totally positive Grassmannian  

Microsoft Academic Search

Tropical algebraic geometry is the geometry of the tropical semiring (R, min, +). The theory of total positivity is a natural generalization of the study of matrices with all minors positive. In this paper we introduce the totally positive part of the tropicalization of an arbitrary affine variety, an object which has the structure of a polyhedral fan. We then

David Speyer; Lauren K. Williams

2003-01-01

202

Total Tuition Activity Athletic Building  

E-print Network

Total Tuition ASUU Activity Athletic Building Collegiate Reader Program Comp- uting Fine Arts.18 $18.81 $3.00 $2.50 $3.00 $42.00 $476.05 $17,394.38 Total Tuition ASUU Activity Athletic Building (3000-5999) in the College of Nursing. Upper-Division Engineering Courses. All students regardless

Feschotte, Cedric

203

MUJERES TOTAL BIOLOGIA 16 27  

E-print Network

PATOLOGICA 2 4 ANATOMIA, HISTOLOGIA Y NEUROCIENCIA 8 12 BIOQUIMICA 38 54 CIRUGIA 13 27 FARMACOLOGIA Y AnatomĂ­a, HistologĂ­a y Neurociencia 1 1 TOTAL MEDICINA 118 84 PsicologĂ­a BiolĂłgica y de la Salud 2 2 TOTAL

Autonoma de Madrid, Universidad

204

Stirling total energy systems study  

Microsoft Academic Search

The application of Stirling cycle prime movers to total energy power generation systems was investigated. Electrical, heating, and cooling demand profiles for a typical residential complex, hospital, and office building were studied, and alternative Stirling total energy systems were conceptualized for each site. These were analyzed in detail and contrasted with purchased power systems for these sites to determine fuel

D. Lehrfeld

1977-01-01

205

Usual Intake of Total seafood  

Cancer.gov

Usual Intake of Total seafood Table A27. Total seafood: Means, percentiles and standard errors of usual intake, 2007-2010 Age (Years) N1 oz equivalents3 Mean (SE)2 5% (SE) 10% (SE) 25% (SE) 50% (SE) 75% (SE) 90% (SE) 95% (SE) Males 1-3 774 0.1 (0.02) 0.0

206

Usual Intake of Total fruit  

Cancer.gov

Usual Intake of Total fruit Table A1. Total fruit: Means, percentiles and standard errors of usual intake, 2007-2010 Age (Years) N1 cup equivalents3 Mean (SE)2 5% (SE) 10% (SE) 25% (SE) 50% (SE) 75% (SE) 90% (SE) 95% (SE) Males 1-3 774 1.5 (0.07) 0.6

207

Cogema acquires TOTAL's uranium assets  

SciTech Connect

On April 28, France's nuclear fuel cycle conglomerate Cogema and petroleum group TOTAL announced a plan in which Cogema will assume ownership of TOTAL's uranium assets worldwide, and as part of the deal, each firm will acquire shares of the other. On June 2, the agreement will be submitted to shareholders and, assuming it is approved, will go into effect this year. The agreement calls for TOTAL to acquire a 10.8-percent share in Cogema, thus becoming its first private sector shareholder, by underwriting a reserve capital increase of FF1.5 billion (approximately US$283 million). In return, Cogema will pay FF2.52 billion for approximately 4.3 percent of TOTAL, as part of a reserve capital increase totalling FF4.07 billion.

Not Available

1993-06-01

208

Labor participation rate, total (% of total population ages 15+)  

NSDL National Science Digital Library

Data set and map pertaining to total labor force participation rates for all countries. The World Bank specifies labor force participation as a World Development Indicator (WDI) -- the statistical benchmark that helps measure the progress of development.

World Bank

209

Total arsenic in rice milk.  

PubMed

Rice milk and its by-products were tested for total arsenic concentration. Total arsenic concentration was determined using graphite-furnace atomic absorption spectrometry. The arsenic concentrations ranged from 2.7 ± 0.3 to 17.9 ± 0.5 µg L(-1). Rice milk and its by-products are not clearly defined as food, water or milk substitute. The US Environmental Protection Agency (EPA), the European Union (EU) and the World Health Organization (WHO) have set a level of 10 µg L(-1) for total arsenic concentrations in drinking water. The EU and the US regulatory agencies do not provide any guidelines on total arsenic concentrations in foods. This study provides us with a starting point to address this issue in the State of Mississippi, USA. PMID:24779982

Shannon, Ron; Rodriguez, Jose M

2014-01-01

210

Fracture After Total Hip Replacement  

MedlinePLUS

... American Academy of Orthopaedic Surgeons. • Dislocation • Limb length inequality • Poor fracture healing • Repeat fracture • Lack of in- ... Surgeons (AAOS). To learn more about your orthopaedic health, please visit orthoinfo.org. Fracture A er Total ...

211

Instability after total knee arthroplasty.  

PubMed

Instability after total knee arthroplasty is reported to result in implant failure, and substantial instability often requires revision surgery. Successful outcomes can be achieved after revision total knee arthroplasty, particularly if the etiology of the instability is identified before the revision procedure. After careful clinical and radiologic analysis, instability can be classified as extension instability, flexion instability, or genu recurvatum. It is important to understand the causes and recommended treatments of each type of instability. PMID:18399593

Parratte, Sebastien; Pagnano, Mark W

2008-01-01

212

Implant based differences in adverse local tissue reaction in failed total hip arthroplasties: a morphological and immunohistochemical study  

PubMed Central

Background Adverse local tissue reaction (ALTR) is characterized by periprosthetic soft tissue inflammation composed of a mixed inflammatory cell infiltrate, extensive soft tissue necrosis, and vascular changes. Multiple hip implant classes have been reported to result in ALTR, and clinical differences may represent variation in the soft tissue response at the cellular and tissue levels. The purpose of this study was to describe similarities and differences in periprosthetic tissue structure, organization, and cellular composition by conventional histology and immunohistochemistry in ALTR resulting from two common total hip arthroplasty (THA) implant classes. Methods Consecutive patients presenting with ALTR from two major hip implant classes (N?=?54 patients with Dual-Modular Neck implant; N?=?14 patients with Metal-on-Metal implant) were identified from our prospective Osteolysis Tissue Database and Repository. Clinical characteristics including age, sex, BMI, length of implantation, and serum metal ion levels were recorded. Retrieved synovial tissue morphology was graded using light microscopy and cellular composition was assessed using immunohistochemistry. Results Length of implantation was shorter in the DMN group versus MoM THA group (21.3 [8.4] months versus 43.6 [13.8] months respectively; p?

2014-01-01

213

Adverse reaction to metal debris is more common in patients following MoM total hip replacement with a 36 mm femoral head than previously thought: results from a modern MoM follow-up programme.  

PubMed

We conducted a retrospective study to assess the prevalence of adverse reactions to metal debris (ARMD) in patients operated on at our institution with metal-on-metal (MoM) total hip replacements with 36 mm heads using a Pinnacle acetabular shell. A total of 326 patients (150 males, 175 hips; 176 females, 203 hips) with a mean age of 62.7 years (28 to 85) and mean follow-up of 7.5 years (0.1 to 10.8) participating in our in-depth modern MoM follow-up programme were included in the study, which involved recording whole blood cobalt and chromium ion measurements, Oxford hip scores (OHS) and plain radiographs of the hip and targeted cross-sectional imaging. Elevated blood metal ion levels (> 5 parts per billion) were seen in 32 (16.1%) of the 199 patients who underwent unilateral replacement. At 23 months after the start of our modern MoM follow-up programme, 29 new cases of ARMD had been revealed. Hence, the nine-year survival of this cohort declined from 96% (95% CI 95 to 98) with the old surveillance routine to 86% (95% CI 82 to 90) following the new protocol. Although ARMD may not be as common in 36 mm MoM THRs as in those with larger heads, these results support the Medicines and Healthcare Products Regulatory Agency guidelines on regular reviews and further investigations, and emphasise the need for specific a follow-up programme for patients with MoM THRs. PMID:25452362

Lainiala, O; Eskelinen, A; Elo, P; Puolakka, T; Korhonen, J; Moilanen, T

2014-12-01

214

Total Quality Management Is Total at Fox Valley Technical College.  

ERIC Educational Resources Information Center

At Fox Valley Technical College (Wisconsin), application of Total Quality Management (TQM) brought positive outcomes and other effects. Areas in which TQM was used are considered, including admissions, employee safety, customer focus, policy formation, management performance appraisal, student services, creation of a self-managing class, TQM for…

Tyler, Carol R.

1993-01-01

215

Total body water and total body potassium in anorexia nervosa  

SciTech Connect

In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

Dempsey, D.T.; Crosby, L.O.; Lusk, E.; Oberlander, J.L.; Pertschuk, M.J.; Mullen, J.L.

1984-08-01

216

Advances in total scattering analysis  

SciTech Connect

In recent years the analysis of the total scattering pattern has become an invaluable tool to study disordered crystalline and nanocrystalline materials. Traditional crystallographic structure determination is based on Bragg intensities and yields the long range average atomic structure. By including diffuse scattering into the analysis, the local and medium range atomic structure can be unravelled. Here we give an overview of recent experimental advances, using X-rays as well as neutron scattering as well as current trends in modelling of total scattering data.

Proffen, Thomas E [Los Alamos National Laboratory; Kim, Hyunjeong [Los Alamos National Laboratory

2008-01-01

217

Total eclipses of the sun.  

PubMed

Total eclipses of the sun offer research opportunities in a variety of sciences. Some of the advances in solar physics resulting from eclipse observations are discussed. Experiments at the total eclipse of 16 February 1980 in India are also described. These included a test of general relativity, studies in coronal physics, investigations of solar prominences, diameter measurements, a search for interplanetary dust, a study of the gravity waves in the earth's atmosphere, and experiments on the biological effects on animals and humans. PMID:17817829

Zirker, J B

1980-12-19

218

The anisotropic total variation flow  

Microsoft Academic Search

We prove existence and uniqueness of solutions of the Anisotropic Total Variation Flow when the initial data is an L2 function and we give a characterization of such solutions that allows us to find explicit evolutions of sets in the presence of an anisotropy.

J. S. Moll

2005-01-01

219

Energy Planning: A Total Concept.  

ERIC Educational Resources Information Center

Harvard's energy conservation plan is presented in detail with the hope that it will suggest practical, cost-effective energy-saving ideas to other institutions, and to dispel frequently-expressed fears concerning the feasibility and acceptance problems of this type of program. The total energy plan incorporates numerous specific elements that…

Hall, Stephen S. J.

1975-01-01

220

Enantioselective Total Synthesis of (?)-Jiadifenolide**  

PubMed Central

The first total synthesis of jiadifenolide (1), a potent neurotrophic modulator, has been reported. Highlights of the synthesis include: construction of the B ring via an asymmetric Robinson annulation; assembly of the E ring lactone via a novel acid-induced cascade reaction; and Pd(0)-mediated carbomethoxylation and methylation reactions for the construction of the C and A rings respectively. PMID:21400650

Xu, Jing; Trzoss, Lynnie; Chang, Weng K.; Theodorakis, Emmanuel. A.

2011-01-01

221

Total Communication Checklist and Assessment.  

ERIC Educational Resources Information Center

The Total Communication Checklist and Assessment screening tool for multihandicapped students is presented to assist the language examiner to select areas requiring more precise testing. The checklist, which contains 196 rating entries, consists of the following four sections: (1) readiness for symbolic communication, (2) preference for speech,…

Waldo, Lois J.; And Others

222

A totally implantable electrical heart.  

PubMed

A totally implantable artificial heart, electrically actuated by magnetical energy transmission was developed in Switzerland. The pusher-plates and roller-screw model was used for the pump. The main advantages of such a mechanical heart are discussed, in particular, the motor that transforms electrical energy into mechanical energy, and allows accurate control of the output and pressures of the artificial ventricles. The system includes the heart, the electronic control of the power supply, the microprocessor for the control of the mechanical heart's performance, a buffer battery, a rectifier and the secondary of the energy transmission. All these elements are implanted. Outside of the body are the main battery, the chopper and the primary of the energy transmission. At present, a left ventricle device for external assistance and a totally artificial heart have both been developed and implanted in calves. An optimized totally artificial heart is in construction, its size being compatible for human implantation; its volume is 500 mL and its total weight is 450 g. PMID:3843614

Jufer, M

1985-01-01

223

MUJERES TOTAL BIOLOGIA 16 24  

E-print Network

NEUROCIENCIA 2 4 BIOQUIMICA 15 28 CIRUGIA 7 15 FARMACOLOGIA Y TERAPEUTICA 1 1 FISIOLOGIA 1 MEDICINA 13 20 19 Anatomía, Histología y Neurociencia 1 1 Medicina 44 25 Farmacología y Terapéutica 19 17 TOTAL

Autonoma de Madrid, Universidad

224

Total Antioxidant Capacity of Fruits  

Microsoft Academic Search

The total antioxidant activity of 12 fruits and 5 commercial fruit juices was measured in this study using automated oxygen radical absorbance capacity (ORAC) assay. On the basis of the wet weight of the fruits (edible portion), strawberry had the highest ORAC activity (micromoles of Trolox equivalents per gram) followed by plum, orange, red grape, kiwi fruit, pink grapefruit, white

Hong Wang; Guohua Cao; Ronald L. Prior

1996-01-01

225

Formal total synthesis of (-)-saliniketals.  

PubMed

A highly stereoselective formal total synthesis of the ornithine decarboxylase inhibitors (-)-saliniketals A and B is described. The salient features of the synthesis are the utilization of a desymmetrization technique to create six contiguous chiral centers from a single bicyclic precursor as well as substrate-controlled Grignard reaction, intramolecular Wacker-type oxidation, and antialdol reaction following Pirrung-Heathcock conditions. PMID:19873991

Yadav, J S; Hossain, Sk Samad; Madhu, Madasu; Mohapatra, Debendra K

2009-11-20

226

Total synthesis of (-)-calyciphylline N.  

PubMed

The total synthesis of the architecturally complex Daphniphyllum alkaloid (-)-calyciphylline N has been achieved. Highlights of the synthesis include a Et2AlCl-promoted, highly stereoselective, susbtrate-controlled intramolecular Diels-Alder reaction, a transannular enolate alkylation, an effective Stille carbonylation/Nazarov cyclization sequence, and a high-risk diastereoselective hydrogenation of a fully substituted conjugated diene ester. PMID:24319987

Shvartsbart, Artem; Smith, Amos B

2014-01-22

227

Total Synthesis of (?)-Calyciphylline N  

PubMed Central

The total synthesis of the architecturally complex Daphniphyllum alkaloid (?)-calyciphylline N has been achieved. Highlights of the synthesis include a Et2AlCl promoted, highly stereoselective susbtrate controlled intramolecular Diels-Alder reaction, a transannular enolate alkylation, an effective Stille carbonylation/Nazarov cyclization sequence, and a high risk dia-stereoselective hydrogenation of a fully substituted conjugated diene ester. PMID:24319987

Shvartsbart, Artem; Smith, Amos B.

2014-01-01

228

TMDLs (Total Maximum Daily Loads)  

NSDL National Science Digital Library

The Water Quality Information Center at the National Agricultural Library (USDA) offers this excellent resource on TMDLs (Total Maximum Daily Loads), with links to dozens of relevant and current publications. From basic questions and answers to current policies regarding TMDLs, this collection of resources is well worth browsing.

229

Total synthesis of alotaketal A.  

PubMed

The total synthesis of the cAMP signaling pathway activator (-)-alotaketal A is reported. A convergent approach to the unusual alotane sesterterpenoid skeleton was employed, exploiting a remarkable LiDBB-mediated coupling of an (R)-carvone-derived ?-lactone with an allyl bromide side chain, followed by spiroacetalization. PMID:23094646

Xuan, Mengyang; Paterson, Ian; Dalby, Stephen M

2012-11-01

230

Standard Length versus Total Length  

Microsoft Academic Search

In an effort to determine the length measurement most representative of the bulk of the fish, the standard length and the total length were each compared with the weight of the fish. This comparison was made for four species of game fish, yellow perch (Perca flavescens), wall-eyed pike (Stizostedion v. vitreum), rock bass (Ambloplites rupestris), and lake trout (Cristivomer n.

William F. Royce

1942-01-01

231

Total phenolics and total flavonoids in selected Indian medicinal plants.  

PubMed

Plant phenolics and flavonoids have a powerful biological activity, which outlines the necessity of their determination. The phenolics and flavonoids content of 20 medicinal plants were determined in the present investigation. The phenolic content was determined by using Folin-Ciocalteu assay. The total flavonoids were measured spectrophotometrically by using the aluminium chloride colorimetric assay. The results showed that the family Mimosaceae is the richest source of phenolics, (Acacia nilotica: 80.63 mg gallic acid equivalents, Acacia catechu 78.12 mg gallic acid equivalents, Albizia lebbeck 66.23 mg gallic acid equivalents). The highest total flavonoid content was revealed in Senna tora which belongs to the family Caesalpiniaceae. The present study also shows the ratio of flavonoids to the phenolics in each sample for their specificity. PMID:23439764

Sulaiman, C T; Balachandran, Indira

2012-05-01

232

Total termination of term rewriting is undecidable  

E-print Network

Total termination of term rewriting is undecidable Hans Zantema Utrecht University, Department. If this order is total on ground terms, the TRS is called totally terminating. In this paper we prove that total]. It is an interesting question whether these orders are total or can be extended to a total monotonic order

Utrecht, Universiteit

233

Solar total energy project Shenandoah  

NASA Astrophysics Data System (ADS)

A description of the final design for the Solar Total Energy System to be installed at the Shenandoah, Georgia, site of utilization by the Bleyle knitwear plant, is presented. The system is a fully cascaded total energy system design featuring high temperature paraboloidal dish solar collectors with a 235 concentration ratio, a steam Rankine cycle power conversion system capable of supplying 100 to 400 kW(e) output with an intermediate process steam take-off point, and a back pressure condenser for heating and cooling. The design also includes an integrated control system employing the supervisory control concept to allow maximum experimental flexibility. The system design criteria and requirements are presented including the performance criteria and operating requirements, environmental conditions of operation; interface requirements with the Bleyle plant and the Georgia Power Company lines; maintenance, reliability, and testing requirements; health and safety requirements; and other applicable ordinances and codes.

1980-01-01

234

Outcome after total hip arthroplasty  

Microsoft Academic Search

The purpose of this study was to examine the relationship between the Harris Hip Score (HHS), a traditional method of patient assessment of a total hip arthroplasty (THA), and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), a commonly used health-related quality-of-life survey. One hundred forty patients returning for routine clinical follow-up evaluation of a primary THA were asked

Jay R. Lieberman; Frederick Dorey; Paul Shekelle; Lana Schumacher; Douglas J. Kilgus; Bert J. Thomas; Gerald A. Finerman

1997-01-01

235

Enantioselective Total Synthesis of Aplyviolene  

PubMed Central

The enantioselective total synthesis of the rearranged spongian diterpene aplyviolene has been completed in 14 steps from the known hydroazulenone 8. The key junction of the hydrocarbon and oxygenated fragments to form the critical C8 quaternary carbon stereocenter and set the stage for elaborating the delicate bicyclic lactone functionality was accomplished in high yield and exquisite stereoselectivity by Michael addition of an enantioenriched hydroazulenone enolate to an enantiopure ?-bromocyclopentenone. PMID:21936525

Overman, Larry E.; Schnermann, Martin J.

2011-01-01

236

Enantioselective total synthesis of borrelidin.  

PubMed

The first total synthesis of the natural product borrelidin is described. The propionate fragment of the molecule was concisely synthesized through catalytic enantioselective reductive aldol reactions, a catalytic Negishi coupling, and a catalytic directed hydrogenation. The propionate segment was then fused to the vinyl iodide fragment through a catalytic Sonogashira coupling. Subsequent catalytic hydrostannylation and catalytic cyanation allowed access to the target structure. PMID:12568588

Duffey, Matthew O; LeTiran, Arnaud; Morken, James P

2003-02-12

237

Total synthesis of (+)-vibsanin A.  

PubMed

The first total synthesis of (+)-vibsanin A, an 11-membered vibsane diterpenoid, was achieved, unambiguously establishing its relative and absolute stereochemistry. Highlights of the synthesis include the stereoselective formation of an all-carbon quaternary stereocenter by a zinc-mediated Barbier-type allylation in an aqueous medium, and the efficient construction of an 11-membered ring skeleton by a combination of an intramolecular Nozaki-Hiyama-Kishi (NHK) reaction and a Mitsunobu reaction. PMID:25622000

Takao, Ken-ichi; Tsunoda, Kohei; Kurisu, Takuya; Sakama, Akihiro; Nishimura, Yoshiyasu; Yoshida, Keisuke; Tadano, Kin-ichi

2015-02-01

238

Asymmetric total synthesis of rollicosin.  

PubMed

[structure: see text] The first total synthesis of rollicosin, a member of a rare subgroup of Annonaceous acetogenins containing two terminal gamma-lactones, is reported. The approach features a highly regio- and stereoselective tandem ring-closing/cross-metathesis reaction for construction of the east-wing lactone and incorporation of the alkyl spacer. Establishment of the C4 stereocenter and addition of the west-wing lactone were achieved by Sharpless asymmetric dihydroxylation and enolate alkylation. PMID:15787477

Quinn, Kevin J; Isaacs, André K; DeChristopher, Brian A; Szklarz, Stephanie C; Arvary, Rebecca A

2005-03-31

239

The essence of total synthesis  

PubMed Central

For the past century, the total synthesis of natural products has served as the flagship of chemical synthesis and the principal driving force for discovering new chemical reactivity, evaluating physical organic theories, testing the power of existing synthetic methods, and enabling biology and medicine. This perspective article seeks to examine this time-honored and highly demanding art, distilling its essence in an effort to ascertain its power and future potential. PMID:15302925

Nicolaou, K. C.; Snyder, Scott A.

2004-01-01

240

URETHROPLASTY FOLLOWING TOTAL PHALLIC RECONSTRUCTION  

Microsoft Academic Search

PurposeTotal phallic reconstruction is often complicated by recalcitrant strictures particularly at the native-to-neourethral anastomosis, which may ultimately require definitive repair. Presumably these strictures form as a result of relative ischemia at the anastomosis of tissues of native urethra to fasciocutaneous tube flap, which is exacerbated by kinking at the neophallus base. The traditional approaches to urethroplasty, such as end-to-end anastomosis,

LAURENCE A. LEVINE; LEV ELTERMAN

1998-01-01

241

Total Synthesis of Theopederin D  

PubMed Central

The total synthesis of the potent cytotoxin theopederin D has been achieved through the use of an oxidative carbon–carbon bond cleavage reaction to form an acyliminium ion in the presence of acid labile acetal groups Other key transformations include an acid mediated functionalization of a tetrahydrofuranyl alcohol in the presence of a tetrahydropyranyl alcohol, a syn-selective glycal epoxide opening, and a catalytic asymmetric aldehyde-acid chloride condensation. PMID:18683833

Green, Michael E.; Rech, Jason C.

2012-01-01

242

Total quality in health care.  

PubMed

Quality is at the top of American consumers' demand list, and consequently American manufacturing companies have been forced to assign priority to the development of high-quality products. To improve the quality of what they offer, many manufacturers use the management philosophy known as total quality management (TQM), and now the service sector is following in their footsteps. The health care industry is a good example of a service industry that can benefit greatly from TQM, and it is the purpose of this article to show how a health care provider can implement TQM and evaluate its effects. PMID:10178544

Brannan, K M

1998-05-01

243

Cardiac dysrhythmia complicating total parotidectomy.  

PubMed

Sudden severe dysrhythmias during anaesthesia can be life- threatening for the patient. We describe a case in which ventricular dysrhythmias and severe bradycardia occurred during dissection and mobilization of the deep lobe of the parotid gland during total parotidectomy under general anaesthesia. We believe that these dysrhythmias were caused by a trigemino- vagal reflex similar to the oculocardiac reflex, but with afferent innervation from mandibular division of the trigeminal nerve. The case report is presented to illustrate a possible existence and importance of reflex bradycardic responses that may occur during surgical procedures involving the parotid gland. PMID:24818345

Prakash, Smita; Sahni, Ameeta; Bamba, Charu; Chintamani; Gogia, Anoop Raj

2013-08-01

244

Total Synthesis of (+)-Superstolide A  

PubMed Central

A convergent and highly stereocontrolled total synthesis of the cytotoxic macrolide (+)-superstolide A is described. Key features of this synthesis include the use of bimetallic linchpin 36b for uniting the C(1)-C(15) (43) and the C(20)-C(27) (38) fragments of the natural product, a late-stage Suzuki macrocyclization of 49, and a highly diastereoselective transannular Diels-Alder reaction of macrocyclic octanene 4. In contrast, the intramolecular Diels-Alder reaction of pentaenal 5 provided the desired cycloadduct with lower stereoselectivity (6:1:1). PMID:18956845

Tortosa, Mariola; Yakelis, Neal A.; Roush, William R.

2009-01-01

245

Antarctic total ozone in 1958  

SciTech Connect

The Antarctic ozone hole results from catalytic destruction of ozone by chlorine radicals. The hole develops in August, reaches its full depth in early October, and is gone by early December of each year. Extremely low total ozone measurements were made at the Antarctic Dumont d'Urville station in 1958. These measurements were derived from spectrographic plates of the blue sky, the moon, and two stars. These Dumont plate data are inconsistent with 1958 Dobson spectrophotometer ozone measurements, inconsistent with present-day Antarctic observations, and inconsistent with meteorological and theoretical information. There is no credible evidence for an ozone hole in 1958.

Newman, P.A. (NASA/Goddard Space Flight Center, Greenbelt, MD (United States))

1994-04-22

246

The total synthesis of (-)-nitidasin.  

PubMed

Nitidasin is a pentacyclic sesterterpenoid with a rare 5-8-6-5 carbon skeleton that was isolated from the Peruvian folk medicine "Hercampuri". It belongs to a small class of sesterterpenoids that feature an isopropyl trans-hydrindane moiety fused to a variety of other ring systems. As a first installment of our general approach toward these natural products, we report the total synthesis of the title compound. Our stereoselective, convergent route involves the addition of a complex alkenyl lithium compound to a trans-hydrindanone, followed by chemoselective epoxidation, ring-closing olefin metathesis, and redox adjustment. PMID:24962933

Hog, Daniel T; Huber, Florian M E; Mayer, Peter; Trauner, Dirk

2014-08-01

247

Total synthesis of sinenside a.  

PubMed

The first total synthesis of norlignan glucoside sinenside A has been accomplished. An intramolecular acetalization reaction has been employed as the key skeletal construct to forge the central cyclic disaccharide core. The trans-1,2-diol configuration present in the cyclic disaccharide of this natural product is unique and has been addressed by setting this configuration at the beginning. A 1,2-orthoester group has been selected as a handle for both sp glycosidation and for differentiation of the C2'-OH (that participates in the key acetalization reaction) of the sugar unit. PMID:25764144

Vadhadiya, Paresh M; Ramana, Chepuri V

2015-04-01

248

Solar total energy project Shenandoah  

SciTech Connect

This document presents the description of the final design for the Solar Total Energy System (STES) to be installed at the Shenandoah, Georgia, site for utilization by the Bleyle knitwear plant. The system is a fully cascaded total energy system design featuring high temperature paraboloidal dish solar collectors with a 235 concentration ratio, a steam Rankine cycle power conversion system capable of supplying 100 to 400 kW(e) output with an intermediate process steam take-off point, and a back pressure condenser for heating and cooling. The design also includes an integrated control system employing the supervisory control concept to allow maximum experimental flexibility. The system design criteria and requirements are presented including the performance criteria and operating requirements, environmental conditions of operation; interface requirements with the Bleyle plant and the Georgia Power Company lines; maintenance, reliability, and testing requirements; health and safety requirements; and other applicable ordinances and codes. The major subsystems of the STES are described including the Solar Collection Subysystem (SCS), the Power Conversion Subsystem (PCS), the Thermal Utilization Subsystem (TUS), the Control and Instrumentation Subsystem (CAIS), and the Electrical Subsystem (ES). Each of these sections include design criteria and operational requirements specific to the subsystem, including interface requirements with the other subsystems, maintenance and reliability requirements, and testing and acceptance criteria. (WHK)

None

1980-01-10

249

Total ozone trend over Cairo  

NASA Technical Reports Server (NTRS)

A world wide interest in protecting ozone layer against manmade effects is now increasing. Assessment of the ozone depletion due to these activities depends on how successfully we can separate the natural variabilities from the data. The monthly mean values of total ozone over Cairo (30 05N) for the period 1968-1988, have been analyzed using the power spectral analysis technique. The technique used in this analysis does not depend on a pre-understanding of the natural fluctuations in the ozone data. The method depends on increasing the resolution of the spectral peaks in order to obtain the more accurate sinusoidal fluctuations with wavelength equal to or less than record length. Also it handles the possible sinusoidal fluctuations with wavelength equal to or less than record length. The results show that it is possible to detect some of the well known national fluctuations in the ozone record such as annual, semiannual, quasi-biennial and quasi-quadrennial oscillations. After separating the natural fluctuations from the ozone record, the trend analysis of total ozone over Cairo showed that a decrease of about -1.2% per decade has occurred since 1979.

Hassan, G. K. Y.

1994-01-01

250

"Total IBA" - Where are we?  

NASA Astrophysics Data System (ADS)

The suite of techniques which are available with the small accelerators used for MeV ion beam analysis (IBA) range from broad beams, microbeams or external beams using the various particle and photon spectrometries (including RBS, EBS, ERD, STIM, PIXE, PIGE, NRA and their variants), to tomography and secondary particle spectrometries like MeV-SIMS. These can potentially yield almost everything there is to know about the 3-D elemental composition of types of samples that have always been hard to analyse, given the sensitivity and the spacial resolution of the techniques used. Molecular and chemical information is available in principle with, respectively, MeV-SIMS and high resolution PIXE. However, these techniques separately give only partial information - the secret of "Total IBA" is to find synergies between techniques used simultaneously which efficiently give extra information. We here review how far "Total IBA" can be considered already a reality, and what further needs to be done to realise its full potential.

Jeynes, C.; Bailey, M. J.; Bright, N. J.; Christopher, M. E.; Grime, G. W.; Jones, B. N.; Palitsin, V. V.; Webb, R. P.

2012-01-01

251

Instability after total knee arthroplasty.  

PubMed

Total knee arthroplasty (TKA) has shown to portend good long-term survivorship and excellent patient satisfaction. There are various etiologies of failure of a TKA. Instability is a major cause of the need for revision. Often, increased constraint is needed to supplement or perform the function of incompetent ligament and soft tissue structures. Posterior cruciate retaining (PCR) TKA has the least constraint. Posterior cruciate substituting (PS) TKA increases sagittal constraint. Varus-valgus constraint (VVC) adds a marked increase in coronal stability. The ultimate in constraint in TKA is a linked hinged implant. In revision TKA, it is the surgeon's responsibility to implant the prosthesis with the necessary constraint to impart adequate stability. PMID:25518877

McNabb, David Clinton; Kim, Raymond H; Springer, Bryan D

2015-04-01

252

Formal total synthesis of aliskiren.  

PubMed

The efficient and selective formal total synthesis of aliskiren is described. Aliskiren, a renin inhibitor drug, has received considerable attention, primarily because it is the first of the renin inhibitor drugs to be approved by the FDA. Herein, the formal synthesis of aliskiren by iridium-catalyzed asymmetric hydrogenation of two allylic alcohol fragments is reported. Screening a number of N,P-ligated iridium catalysts yielded two catalysts that gave the highest enantioselectivity in the hydrogenation, which gave the saturated alcohols in 97 and 93?% ee. In only four steps after hydrogenation, the fragments were combined by using the Julia-Kocienski reaction to produce late-stage intermediate in an overall yield of 18?%. PMID:25783891

Peters, Byron K; Liu, Jianguo; Margarita, Cristiana; Andersson, Pher G

2015-05-01

253

Total Synthesis of (+)-Papulacandin D  

PubMed Central

A total synthesis of (+)-papulacandin D has been achieved in 31 steps, in a 9.2% overall yield from commercially available materials. The synthetic strategy divided the molecule into two nearly equal sized subunits, the spirocyclic C-arylglycopyranoside and the polyunsaturated fatty acid side chain. The C-arylglycopyranoside was prepared in 11 steps in a 30% overall yield from triacetoxyglucal. The fatty acid side chain was also prepared in 11 steps in a 30% overall yield from geraniol. The key strategic transformations in the synthesis are: (1) a palladium-catalyzed, organosilanolate-based cross-coupling reaction of a dimethylglucal-silanol with an electron rich and sterically hindered aromatic iodide and (2) a Lewis base-catalyzed, enantioselective allylation reaction of a dienal and allyltrichlorosilane. A critical element in the successful execution of the synthesis was the development of a suitable protecting group strategy that satisfied a number of stringent criteria. PMID:20711516

Denmark, Scott E.; Kobayashi, Tetsuya; Regens, Christopher S.

2010-01-01

254

TVD: Total Variation Diminishing code  

NASA Astrophysics Data System (ADS)

TVD solves the magnetohydrodynamic (MHD) equations by updating the fluid variables along each direction using the flux-conservative, second-order, total variation diminishing (TVD), upwind scheme of Jin & Xin. The magnetic field is updated separately in two-dimensional advection-constraint steps. The electromotive force (EMF) is computed in the advection step using the TVD scheme, and this same EMF is used immediately in the constraint step in order to preserve ?Ë?B=0 without the need to store intermediate fluxes. The code is extended to three dimensions using operator splitting, and Runge-Kutta is used to get second-order accuracy in time. TVD offers high-resolution per grid cell, second-order accuracy in space and time, and enforcement of the ?Ë?B=0 constraint to machine precision. Written in Fortran, It has no memory overhead and is fast. It is also available in a fully scalable message-passing parallel MPI implementation.

Pen, Ue-Li; Arras, Phil; Wong, ShingKwong

2013-04-01

255

Total quality management implementation guidelines  

SciTech Connect

These Guidelines were designed by the Energy Quality Council to help managers and supervisors in the Department of Energy Complex bring Total Quality Management to their organizations. Because the Department is composed of a rich mixture of diverse organizations, each with its own distinctive culture and quality history, these Guidelines are intended to be adapted by users to meet the particular needs of their organizations. For example, for organizations that are well along on their quality journeys and may already have achieved quality results, these Guidelines will provide a consistent methodology and terminology reference to foster their alignment with the overall Energy quality initiative. For organizations that are just beginning their quality journeys, these Guidelines will serve as a startup manual on quality principles applied in the Energy context.

Not Available

1993-12-01

256

Total synthesis of maoecrystal v.  

PubMed

Maoecrystal V (1) is a novel diterpenoid, which was originally isolated from the leaves of the Chinese medicinal herb Isodon eriocalyx in 2004 by Sun et?al.1 It has been found to be selectively cytotoxic towards HeLa cells, with an IC50 value of 20?ng?mL(-1) . Significant research efforts have been devoted to the synthesis of maoecrystal V because of its intriguing biological properties, rarity in nature, and complex structural features. Herein, we describe our recent investigations, which have culminated in the total synthesis of (±)-maoecrystal V. The current strategy involved three key steps for the successful construction of the key tetrahydrofuran oxa-bridge skeleton, including a Wessely oxidative dearomatization, a novel intramolecular Diels-Alder reaction, and a Rh(II) -catalyzed O?H insertion reaction. PMID:25504983

Zhang, Wei-Bin; Lin, Guang; Shao, Wen-Bin; Gong, Jian-Xian; Yang, Zhen

2015-04-01

257

Total quality management program planning  

SciTech Connect

As government funding grows scarce, competition between the national laboratories is increasing dramatically. In this era of tougher competition, there is no for resistance to change. There must instead be a uniform commitment to improving the overall quality of our products (research and technology) and an increased focus on our customers` needs. There has been an ongoing effort to bring the principles of total quality management (TQM) to all Energy Systems employees to help them better prepare for future changes while responding to the pressures on federal budgets. The need exists for instituting a vigorous program of education and training to an understanding of the techniques needed to improve and initiate a change in organizational culture. The TQM facilitator is responsible for educating the work force on the benefits of self-managed work teams, designing a program of instruction for implementation, and thus getting TQM off the ground at the worker and first-line supervisory levels so that the benefits can flow back up. This program plan presents a conceptual model for TQM in the form of a hot air balloon. In this model, there are numerous factors which can individually and collectively impede the progress of TQM within the division and the Laboratory. When these factors are addressed and corrected, the benefits of TQM become more visible. As this occurs, it is hoped that workers and management alike will grasp the ``total quality`` concept as an acceptable agent for change and continual improvement. TQM can then rise to the occasion and take its rightful place as an integral and valid step in the Laboratory`s formula for survival.

Thornton, P.T.; Spence, K.

1994-05-01

258

UNIVERSITY OF HAWAII AT MANOA FACULTY AND STAFF Men Women Total Men Women Total Men Women Total  

E-print Network

UNIVERSITY OF HAWAII AT MANOA FACULTY AND STAFF Men Women Total Men Women Total Men Women Total: December 3, 2012 University of Hawaii at Manoa FTE (fulltime equivalent)Total FullTime Grade Level 37% Office of the Vice Chancellor for Academic Affairs Manoa Institutional Research miro@hawaii.edu 1

Wang, Yuqing

259

Stiffness after total knee arthroplasty.  

PubMed

Stiffness after total knee arthroplasty (TKA) adversely affects outcome and impacts patient function. Various risk factors for stiffness after TKA have been identified, including reduced preoperative knee range of motion, history of prior knee surgery, etiology of arthritis, incorrect positioning or oversizing of components, and incorrect gap balancing. Mechanical and associated causes, such as infection, arthrofibrosis, complex regional pain syndrome, and heterotopic ossification, secondary gain issues have also been identified. Management of stiffness following TKA can be challenging. The condition needs to be assessed and treated in a staged manner. A nonsurgical approach is the first step. Manipulation under anesthesia may be considered within the first 3 months after the index TKA, if physical therapy fails to improve the range of motion. Beyond this point, consideration should be given to surgical intervention such as lysis of adhesions, either arthroscopically or by open arthrotomy. If the cause of stiffness is deemed to be surgical error, such as component malpositioning, revision arthroplasty is indicated. The purpose of this article is to evaluate the various aspects of management of stiffness after TKA. PMID:25513992

Manrique, Jorge; Gomez, Miguel M; Parvizi, Javad

2015-04-01

260

Enantioselective Total Synthesis of (?)-Acutumine  

PubMed Central

An account of the total synthesis of the tetracyclic alkaloid (?)-acutumine is presented. A first-generation approach to the spirocyclic subunit was unsuccessful due to incorrect regioselectivity in a radical cyclization. However, this work spawned a second-generation strategy in which the spirocycle was fashioned via a radical–polar crossover reaction. This process merged an intramolecular radical conjugate addition with an enolate hydroxylation, and created two stereocenters with excellent diastereoselectivity. The reaction was promoted by irradiation with a sunlamp, and a ditin reagent was required for aryl radical formation. These facts suggest that the substrate may function as a sensitizer, thereby facilitating homolytic cleavage of the ditin reagent. The propellane motif of the target was then installed via annulation of a pyrrolidine ring onto the spirocycle. The sequence of reactions used included a phenolic oxidation, an asymmetric ketone allylation mediated by Nakamura’s chiral allylzinc reagent, an anionic oxy-Cope rearrangement, a one-pot ozonolysis–reductive amination, and a Lewis acid promoted cyclization of an amine onto an ?,?-unsaturated dimethyl ketal. Further studies of the asymmetric ketone allylation demonstrated the ability of the Nakamura reagent to function well in a mismatched situation. A TiCl4-catalyzed regioselective methyl enol etherification of a 1,3-diketone completed the synthesis. PMID:19904909

Li, Fang; Tartakoff, Samuel S.; Castle, Steven L.

2009-01-01

261

Enantiocontrolled total synthesis of (-)-mersicarpine.  

PubMed

A racemic synthesis of mersicarpine (1) was achieved by the Mizoroki-Heck reaction and a DIBALH-mediated reductive ring-expansion reaction. Based on a first-generation synthesis, a second-generation enantiocontrolled total synthesis of (-)-mersicarpine (1) was achieved by an 8-pot/11-step sequence in 21% overall yield from commercially available 2-ethylcyclohexanone. Subjection of a ketoester, which was prepared by an asymmetric Michael addition (according to the protocol by d'Angelo and Desmaële), and phenylhydrazine to modified Fischer indole conditions provided a six-membered tricyclic indole. Benzylic oxidation and subsequent oxime formation provided a ketoxime, which was treated with diisobutylaluminum hydride (DIBALH) to construct the characteristic azepinoindole skeleton in good yield. In the DIBALH-mediated reductive ring-expansion reaction, gradually increasing the reaction temperature and in situ-protection of the nitrogen in an oxygen-sensitive azepinoindole with a benzyloxycarbonyl (Cbz) group were crucial for the high-yielding process. With these methodologies, the short-step and efficient synthesis of (-)-mersicarpine was accomplished. Several synthetic efforts are also described. PMID:23729297

Iwama, Yusuke; Okano, Kentaro; Sugimoto, Kenji; Tokuyama, Hidetoshi

2013-07-01

262

Total Petroleum Systems and Assessment Units (AU)  

E-print Network

Total Petroleum Systems (TPS) and Assessment Units (AU) Field type Surface water Groundwater X X X X X X X X AU 00000003 Oil/ Gas X X X X X X X X Total X X X X X X X Total Petroleum Systems (TPS) and Assessment Units (AU) Field type Total undiscovered petroleum (MMBO or BCFG) Water per oil

Torgersen, Christian

263

Categories of domains with totality Dag Normann  

E-print Network

Categories of domains with totality Dag Normann June 2, 2000 Abstract We investigate domains with totality where density in general does not hold. We define three categories of domains X with totality â?˘ X. These will induce domains with totality. We show that the set of evaluation structures in a natural way is closed

Normann, Dag

264

Total Algorithms \\Lambda Gerard Tel y  

E-print Network

Total Algorithms \\Lambda Gerard Tel y Department of Computer Science, University of Utrecht, P and February 1993 Abstract We define the notion of total algorithms for networks of processes. A total processes is required to reach this decision. Total algorithms are an important building block in the design

Utrecht, Universiteit

265

Full Abstraction, Totality and PCF Gordon Plotkin  

E-print Network

Full Abstraction, Totality and PCF Gordon Plotkin Abstract Inspired by a question of Riecke, we consider the interaction of totality and full abstraction, asking whether full abstraction holds for Scott's model of cpos and continuous functions if one restricts to total programs and total observations

Plotkin, Gordon

266

Total Education in the Total Environment, An Introduction to the Application of a Total Environment Approach to Education.  

ERIC Educational Resources Information Center

Project TETE (Total Education in the Total Environment, a multidisciplinary approach to environmental education utilizing existing curricula, is described in this booklet. It is a community-wide strategy to enable all members of the community to discover the connecting processes which fashion the total environment, stressing that every community…

Eblen, William R.

267

Recommended Amounts of Total starchy vegetables  

Cancer.gov

Recommended Amounts of Total starchy vegetables Table B6. Total starchy vegetables: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation

268

CALIFORNIA CITIES WITH 1990 & 2000 POPULATION TOTALS  

EPA Science Inventory

Point locations represent cities with Census 2000 population totals and 1990 Census population totals. Cities represent Census Designated Place (CDP) as classified by the US Bureau of the Census. CDP comprise densely settled concentrations of population that are identifiable by...

269

ARIZONA CITIES WITH 1990 & 2000 POPULATION TOTALS  

EPA Science Inventory

Point locations represent cities with Census 2000 population totals and 1990 Census population totals. Cities represent Census Designated Place (CDP) as classified by the US Bureau of the Census. CDP comprise densely settled concentrations of population that are identifiable by...

270

NEVADA CITIES WITH 1990 & 2000 POPULATION TOTALS  

EPA Science Inventory

Point locations represent cities with Census 2000 population totals and 1990 Census population totals. Cities represent Census Designated Place (CDP) as classified by the US Bureau of the Census. CDP comprise densely settled concentrations of population that are identifiable by...

271

HAWAII CITIES WITH 1990 & 2000 POPULATION TOTALS  

EPA Science Inventory

Point locations represent cities with Census 2000 population totals and 1990 Census population totals. Cities represent Census Designated Place (CDP) as classified by the US Bureau of the Census. CDP comprise densely settled concentrations of population that are identifiable by...

272

Total cost model for making sourcing decisions  

E-print Network

This thesis develops a total cost model based on the work done during a six month internship with ABB. In order to help ABB better focus on low cost country sourcing, a total cost model was developed for sourcing decisions. ...

Morita, Mark, M.B.A. Massachusetts Institute of Technology

2007-01-01

273

Frustrated Total Internal Reflection Optics & Photonics  

E-print Network

. Peter Palffy-Muhoray #12;Curved path Straight path 1. Lossless #12;2. Evanescent waves Total Internal Reflection Fluorescence Microscopy Total Internal Reflection Biosensors #12;3. Evanescent-wave coupling #12Frustrated Total Internal Reflection Optics & Photonics Student: Pedro Coutino Soto Professor: Dr

Palffy-Muhoray, Peter

274

History of Total Communication in Oshkosh  

ERIC Educational Resources Information Center

Examined with 17 elementary level deaf children were the integration of deaf children with an oral, integrated instructional background with a deaf class with a total communication instructional background and the integration of deaf children with partial or total reliance on total communication with a hearing class. (SBH)

Schallhorn, Dave

1977-01-01

275

Population Total White Alone Alone Asian Alone  

E-print Network

Hispanic or Latino Total Population Total White Alone Black or African American Alone American Indian and Alaska Native Alone Asian Alone Native Hawaiian and Other Pacific Islander Alone Some Other Race Alone Two or More Races Total Share Rank State of Utah 2,757,779 331,637 2,246,136 26,639 31

Capecchi, Mario R.

276

Total quality management: the second industrial revolution  

Microsoft Academic Search

This article describes the concept and basic approach to total quality management. Quality is examined and explained in the context of continuous customer's satisfaction and total quality management by involving everyone's commitment to achieving quality at a low cost. Different stages of total quality management in practice are suggested and various techniques to implement these are also discussed. It has

Gopal K. Kanji

1990-01-01

277

The Total Quality Movement in Education.  

ERIC Educational Resources Information Center

The total quality movement began as a result of the desire of W. Edwards Deming, an American statistician, to permit the economic system to maintain its edge in a growing global market. The 14 points Deming listed as essential to "total quality management" have recently been adapted to the field of education. The success of the total quality…

Leuenberger, John A.; Whitaker, Sheldon V., Jr.

278

About Total Lubricants USA, Inc. Headquartered in Linden, New Jersey, Total Lubricants USA provides  

E-print Network

About Total Lubricants USA, Inc. Headquartered in Linden, New Jersey, Total Lubricants USA provides. A subsidiary of Total, S.A., the world's fourth largest oil company, Total Lubricants USA still fosters its. Situation Total Lubricants USA operates across multiple facilities, relying on an integrated

Fisher, Kathleen

279

Trends in total column ozone measurements  

NASA Technical Reports Server (NTRS)

It is important to ensure the best available data are used in any determination of possible trends in total ozone in order to have the most accurate estimates of any trends and the associated uncertainties. Accordingly, the existing total ozone records were examined in considerable detail. Once the best data set has been produced, the statistical analysis must examine the data for any effects that might indicate changes in the behavior of global total ozone. The changes at any individual measuring station could be local in nature, and herein, particular attention was paid to the seasonal and latitudinal variations of total ozone, because two dimensional photochemical models indicate that any changes in total ozone would be most pronounced at high latitudes during the winter months. The conclusions derived from this detailed examination of available total ozone can be split into two categories, one concerning the quality and the other the statistical analysis of the total ozone record.

Rowland, F. S.; Angell, J.; Attmannspacher, W.; Bloomfield, P.; Bojkov, R. D.; Harris, N.; Komhyr, W.; Mcfarland, M.; Mcpeters, R.; Stolarski, R. S.

1989-01-01

280

Wear mechanisms and improvements of wear resistance in cobalt-chromium alloy femoral components in artificial total knee joints  

NASA Astrophysics Data System (ADS)

Wear is one of the major causes of artificial total knee arthroplasty (TKA) failure. Wear debris can cause adverse reactions to the surrounding tissue which can ultimately lead to loosening of the prosthesis. The wear behavior of UHMWPE tibial components have been studied extensively, but relatively little attention has been paid to the CoCrMo femoral component. The goal of the present study was to investigate the wear mechanisms of CoCrMo femoral components, to study the effect of CoCrMo alloy surface roughness on the wear of UHMWPE, and to determine the effect of heat treatments on the wear resistance of the CoCrMo implant alloys. The surface roughness of twenty-seven retrieved CoCrMo femoral components was analyzed. A multiple station wear testing machine and a wear fixture attached to an MTS 858 bionix system were built and used for in vitro wear studies of the CoCrMo/UHMWPE bearing couple. Solution and aging treatments were applied to the CoCrMo alloys. A white light interference surface profilometer (WLISP) and a scanning electron microscope (SEM) were used to measure the surface roughness and to study wear mechanisms of CoCrMo alloy. An optical microscope was used for alloy microstructure study. X-ray diffraction tests were performed to identify alloy phase transformation after aging. The micro-structure, hardness, and wear resistance of the alloys were studied. Surface roughness was used to quantify alloy wear, and the minimum number of surface roughness measurements required to obtain a reliable and repeatable characterization of surface roughness for a worn alloy surface was determined. The surfaces of the retrieved CoCrMo femoral components appeared to be damaged by metal particles embedded in the UHMWPE tibial component and metal-on-metal wear due to UHMWPE tibial component through-wear. Surface roughness of the femoral components was not correlated with patient age, weight, sex, or length of implantation. In vitro wear tests showed that when the CoCrMo alloy surface roughness was higher than 0.022 mum Ra (surface roughness average), UHMWPE wear increased with increasing CoCrMo alloy surface roughness. Bone and poly(methyl methacrylate) (PMMA) bone cement abrasive particles created scratches on the alloy via a ploughing mechanism, and resulted in significantly rougher surfaces than controls without particles (P < 0.01). Solution treatments at 1230sp°C and 1245sp°C reduced the hardness and wear resistance of the as-cast F75 CoCrMo alloy. Aging at 700sp°C caused recrystallization of the forged F799 alloy and improved wear resistance. Thermo-mechanical treatments have the potential to increase the lifetime of artificial joints by increasing the wear resistance of CoCrMo components.

Que, Like

281

LL-TIME PAR TOTAL B. BY TERM ENTRANCE STATUS School Colleges of Absence Term TOTAL  

E-print Network

LL-TIME PAR TOTAL e B. BY TERM ENTRANCE STATUS School Colleges of Absence Term TOTAL Total undergraduate level 908 46 45 2,513 3,512 Total Post-Baccalaureate 0 4 2 36 42 Total graduate level 0 249 6 728 983 Arts & Sciences Total 908 299 53 3,277 4,537 9/25/2009 JOHNS HOPKINS UNIVERSITY Office of 2009

Weaver, Harold A. "Hal"

282

Comparative outcomes of total joint arthroplasty  

Microsoft Academic Search

A prospective pre- and postoperative general health\\/quality-of-life factor comparison, using the Rand SF-36 Health Status Questionnaire (TyPE Specification, Quality Quest [Health Outcomes Institute, Minneapolis, MN]), was carried out on a consecutive series of patients with diagnosed osteoarthritis undergoing total hip and knee arthroplasty between March 1991 and March 1994. Study groups consisted of 85 total hip arthroplasty patients, 93 total

Merrill A. Ritter; Marjorie J. Albohm; E. Michael Keating; Philip M. Faris; John B. Meding

1995-01-01

283

Total solar eclipse of 3 November 1994  

NASA Technical Reports Server (NTRS)

A total eclipse of the Sun will be visible from the southern half of the Western Hemisphere on 3 November 1994. The path of the Moon's shadow passes through Peru, Chile, Bolivia, Paraguay, and Brazil. Detailed predictions for this event are presented and include tables of geographic coordinates of the path of totality, local circumstances for hundreds of cities, maps of the path of total and partial eclipse, weather prospects, and the lunar limb profile.

Espenak, Fred; Anderson, Jay

1993-01-01

284

Facts and figures PG UG Total  

E-print Network

Facts and figures PG UG Total UK 1,969 7,009 8,978 EU 375 658 1,033 Other European 39 88 127 Africa America/Caribbean 67 26 93 From UK 83% From rest of world 17% Students by domicile Female Male Total Postgraduate 1,805 1,520 3,325 Undergraduate 4,626 3,527 8,153 Total 6,431 5,047 11,478 Female 56% Male 44

Sussex, University of

285

Free radical scavenging activity, total phenolic content, total antioxidant status, and total oxidant status of endemic Thermopsis turcica  

PubMed Central

Thermopsis turcica, endemic to Turkey, is in danger of extinction. Studies on this species are very few due to the fact that it was only discovered in 1983 and grows in a small circumscribed area in Turkey. In this study, free radical scavenging activity, total phenolic content, total oxidant status (TOS), and total antioxidant status (TAS) of methanol (TTM) and acetone (TTA) extracts of T. turcica were measured spectroscopically. Free radical scavenging activity was determined according to the elimination of DPPH radicals and total phenol content was determined by the Folin–Ciocalteu reaction. Total oxidant status (TOS) and total antioxidant status (TAS) were measured with commercially available kits. Methanol and acetone extracts of T. turcica were found to have a specific radical scavenging effect. This effect was found to be related to the total phenolic content of the extracts. Since the TTA had a higher phenolic content than the methanol extract, it had a stronger radical scavenging effect. In addition, the total antioxidant capacity of the methanol extract was observed to be higher than that of its acetone counterpart. As a result, due to its antioxidative properties, T. turcica is thought to be a natural source of antioxidants. PMID:23961240

Aksoy, Laçine; Kolay, Erdi; A??lönü, Yasin; Aslan, Zeyneb; Karg?o?lu, Mustafa

2013-01-01

286

Computation of orbits using total energy  

NASA Technical Reports Server (NTRS)

The computation of orbits can be done more efficiently by the use of any of several new formulations of the perturbed two body problem which consider the total energy of the orbital system as one of the dependent variables. The total energy is the osculating two body energy plus the potential energy due to perturbing masses. The use of the total energy as the dependent variable instead of the two body energy is a relatively new idea. The advantage of using total energy arises from the fact that the more perturbing potential energy that is accounted for in the total energy variable, the more nearly constant is the total energy. In fact, except for dissipative forces such as drag, the only reason for the total energy not being constant is the rotation or revolution of the perturbing mass. This near constancy of the total energy has the effect of inhibiting error growth during numerical solution. This paper will present the results of an application of total energy formulation to the problem of the precise computation of orbits.

Bond, Victor R.; Mulcihy, David D.

1988-01-01

287

Basic principles and uniform terminology for the head-neck junction in hip replacement.  

PubMed

Recent problems with large head metal on metal hip replacements have spiked renewed interest in the head-neck junction. A thorough knowledge of the principles of the locking mechanism, the assembly technique and affecting factors on the strength of this junction is needed. Currently a confusing variability in terms is used to describe this junction. This overcomplicates an already complex issue. The purpose of this literature review is to collect and list the different terms used and to propose a uniform terminology. Two authors independently searched the electronic databases of PubMed, CINAHL and MEDLINE with specific key words and combinations according to the PRISMA guidelines. The initial search yielded a total of 518 articles with ultimately 53 articles included in the present analysis. No consensus for a uniform term for the 2 sides of the head-stem junction was found. Since there is already pronounced variability in taper designs between different manufacturers (even so similarly named, e.g. "12/14"), a uniform terminology could be the first step to simplify the situation. "Male" and "female taper" is proposed as the appropriate terminology for the stem and head junction in hip replacement, respectively. The importance of the assembly technique understanding the principles of the locking mechanism is emphasised. PMID:25362881

Werner, Paul H; Ettema, Harmen B; Witt, Florian; Morlock, Michael M; Verheyen, Cees C P M

2015-04-20

288

25The Last Total Solar Eclipse...Ever! Total solar eclipses happen  

E-print Network

25The Last Total Solar Eclipse...Ever! Total solar eclipses happen because the angular size a total solar eclipse. When will that happen? Image courtesy Fred Espenak http://sunearth.gsfc.nasa.gov/eclipse/eclipse the distance from your answer to Problem 4? Problem 7 - When will the last Total Solar Eclipse be sighted

289

TOTAL MUJERES TOTAL MUJERES FACULTAD DE CIENCIAS 221 117 147 107 368 224  

E-print Network

TOTAL MUJERES TOTAL MUJERES FACULTAD DE CIENCIAS 221 117 147 107 368 224 FACULTAD DE CIENCIAS PSICOLOGĂŤA 88 76 68 63 156 139 TOTAL CENTROS PROPIOS 1.443 921 1.019 690 2.462 1.611 CENTRO SUPERIOR DE 5 4 TOTAL CENTROS ADSCRITOS 13 12 20 19 33 31 TOTAL UAM 1.456 933 1.039 709 2.495 1.642 curso

Autonoma de Madrid, Universidad

290

TOTAL MUJERES TOTAL MUJERES FACULTAD DE CIENCIAS 148 79 173 82 321 161  

E-print Network

TOTAL MUJERES TOTAL MUJERES FACULTAD DE CIENCIAS 148 79 173 82 321 161 FACULTAD DE CIENCIAS DE PSICOLOGĂŤA 103 81 108 93 211 174 TOTAL CENTROS PROPIOS 1.452 963 1.179 703 2.631 1.666 CENTRO DĂŤAZ 2 2 4 4 6 6 TOTAL CENTROS ADSCRITOS 35 34 30 29 65 63 TOTAL UAM 1.487 997 1.209 732 2.696 1

Autonoma de Madrid, Universidad

291

Total Quality Management in Education. Second Edition.  

ERIC Educational Resources Information Center

Quality is at the top of most agendas, and improving quality is probably the most important task facing any institution. In addition, quality is difficult to define or measure. This book, the second edition of "Total Quality Management in Education," introduces the key concepts of Total Quality Management (TQM) and demonstrates how they can be put…

Sallis, Edward

292

Preoperative Evaluations in Revision Total Knee Arthroplasty  

Microsoft Academic Search

There are many causes of total knee arthroplasty failure, and an accurate preoperative diagnosis is essential to optimize the results of revision surgery. We discuss our standard pre- operative evaluation routine and we retrospectively reviewed the last 295 patients who underwent revision total knee ar- throplasty to establish the clinical value of the most com- monly performed investigations used to

Steven J. MacDonald; Robert B. Bourne

2006-01-01

293

Population Total White Alone Alone Asian Alone  

E-print Network

Hispanic or Latino Total Population Total White Alone Black or African American Alone American Alone Black or African American Alone American Indian and Alaska Native Alone Asian Alone Native Indian and Alaska Native Alone Asian Alone Native Hawaiian and Other Pacific Islander Alone Some Other

294

Total Variation in Imaging V. Caselles  

E-print Network

, stereo imaging and 3D surface reconstruction, segmentation, or interpolation, to mention some of them of max-flow algorithms. Then we review the use of anisotropic total variation models to solve different. On the other, we review the main numerical approaches to solve different models where total variation appears

Novaga, Matteo

295

Total Quality and the Human Resource Professional  

Microsoft Academic Search

Interest in the total quality concept has been gaining considerable momentum within North America. Total quality, which is founded on the belief that organizations can succeed by meeting the needs of their customers, has traditionally been a concern of line management. However, specialists in the area of human and industrial relations have been espousing some of the concepts touted by

Fred Palumbo; Bradley S. O’Hara; Paul A. Herbig

1994-01-01

296

A High Performance Totally Ordered Multicast Protocol  

Microsoft Academic Search

This paper presents the Reliable Multicast Protocol (RMP). RMP provides a totally ordered, reliable, atomic multicast service on top of an unreliable multicast datagram service such as IP Multicasting. RMP is fully and symmetrically distributed so that no site bears an undue portion of the communication load. RMP provides a wide range of guarantees, from unreliable delivery to totally ordered

Brian Whetten; Todd Montgomery; Simon M. Kaplan

1994-01-01

297

Usual Intake of Total whole fruit  

Cancer.gov

Usual Intake of Total whole fruit Table A2. Total whole fruit: Means, percentiles and standard errors of usual intake, 2007-2010 Age (Years) N1 cup equivalents3 Mean (SE)2 5% (SE) 10% (SE) 25% (SE) 50% (SE) 75% (SE) 90% (SE) 95% (SE) Males 1-3 774 0.8

298

Usual Intake of Total starchy vegetables  

Cancer.gov

Usual Intake of Total starchy vegetables Table A12. Total starchy vegetables: Means, percentiles and standard errors of usual intake, 2007-2010 Age (Years) N1 cup equivalents3 Mean (SE)2 5% (SE) 10% (SE) 25% (SE) 50% (SE) 75% (SE) 90% (SE) 95% (SE) Males 1-3 774 0.2

299

TOTAL REFLUX OPERATION OF MULTIVESSEL BATCH DISTILLATION  

E-print Network

TOTAL REFLUX OPERATION OF MULTIVESSEL BATCH DISTILLATION BERND WITTGENS, RAJAB LITTO, EVA S RENSEN a generalization of previously proposed batch distillation schemes. A simple feedback control strategy for total re verify the simulations. INTRODUCTION Although batch distillation generally is less energy e cient than

Skogestad, Sigurd

300

EVALUATION OF TOTAL ORGANIC EMISSIONS ANALYSIS METHODS  

EPA Science Inventory

The rationale and supporting experimental data for revising EPA's 1996 "Guidance for Total Organics" are summarized in this document. It reports the results of reseach and investigation of improvements to the Total Organic Emissions (TOE) guidance used by EPA to measure recovera...

301

Total correlations as fully additive entanglement monotones  

E-print Network

We generalize the strategy presented in Refs. [1, 2], and propose general conditions for a measure of total correlations to be an entanglement monotone using its pure (and mixed) convex-roof extension. In so doing, we derive crucial theorems and propose a concrete candidate for a total correlations measure which is a fully additive entanglement monotone.

Gerardo A. Paz-Silva; John H. Reina

2007-04-05

302

Early clinical failure of the Birmingham metal-on-metal hip resurfacing is associated with metallosis and soft-tissue necrosis.  

PubMed

The rate and mode of early failure in 463 Birmingham hip resurfacings in a two-centre, multisurgeon series were examined. Of the 463 patients two have died and three were lost to follow-up. The mean radiological and clinical follow-up was for 43 months (6 to 90). We have revised 13 resurfacings (2.8%) including seven for pain, three for fracture, two for dislocation and another for sepsis. Of these, nine had macroscopic and histological evidence of metallosis. The survival at five years was 95.8% (95% confidence interval (CI) 94.1 to 96.8) for revision for all causes and 96.9% (95% CI 95.5 to 98.3) for metallosis. The rate of metallosis related revision was 3.1% at five years. Risk factors for metallosis were female gender, a small femoral component, a high abduction angle and obesity. We do not advocate the use of the Birmingham Hip resurfacing procedure in patients with these risk factors. PMID:19651828

Ollivere, B; Darrah, C; Barker, T; Nolan, J; Porteous, M J

2009-08-01

303

Enantioselective total syntheses of cyathane diterpenoids.  

PubMed

A Personal Account describing the enantioselective total syntheses of cyathane diterpenoids achieved in the Nakada group. A convergent approach to the cyathane scaffold, the [5-6-7] tricyclic carbon skeleton commonly found in cyathane diterpenoids, has been developed using the catalytic asymmetric intramolecular cyclopropanation (CAIMCP) and baker's yeast reduction. This approach has been successfully applied for the enantioselective total syntheses of (+)-allocyathin B2 , (-)-erinacine B, and (-)-erinacine E. The total synthesis of (-)-erinacine E has been achieved via the acyl group migratory intramolecular aldol reaction, which prevents the retro-aldol reaction and allows the construction of the strained structure. The highly efficient and stereoselective total syntheses of (-)-scabronines G, A, D, and (-)-episcabronine A have been achieved via the oxidative dearomatization/inverse electron demand Diels-Alder reaction cascade. Cascade reactions comprising three and five consecutive reactions were employed for the highly efficient total syntheses of (-)-scabronine A and (-)-episcabronine A, respectively. PMID:25065736

Nakada, Masahisa

2014-08-01

304

Single-Incision Laparoscopic Total Colectomy  

PubMed Central

Background and Objectives: To present our experience with a single-incision laparoscopic total colectomy, along with a literature review of all published cases on single-incision laparoscopic total colectomy. Methods: A total of 22 cases were published between 2010 and 2011, with our patient being case 23. These procedures were performed in the United States and United Kingdom. Surgical procedures included total colectomy with end ileostomy, proctocolectomy with ileorectal anastomosis, and total proctocolectomy with ileopouch-anal anastomosis. Intraoperative and postoperative data are analyzed. Results: Twenty-two of the 23 cases were performed for benign cases including Crohns, ulcerative colitis, and familial adenomatous polyposis. One case was performed for adenocarcinoma of the cecum. The mean age was 35.3 years (range, 13 to 64), the mean body mass index was 20.1 (range, 19 to 25), mean operative time was 175.9 minutes (range, 139 to 216), mean blood loss was 95.3mL (range, 59 to 200), mean incision length was 2.61cm (range, 2 to 3). Average follow-up was 4.6 months with 2 reported complications. Conclusions: Single-incision laparoscopic total colectomy is feasible and safe in the hands of an experienced surgeon. It has been performed for both benign and malignant cases. It is comparable to the conventional multi-port laparoscopic total colectomy. PMID:22906326

Ojo, Oluwatosin J.; Carne, David; Guyton, Daniel

2012-01-01

305

Total Solar Eclipse: Live from Turkey  

NSDL National Science Digital Library

On March 29, 2006, a team from the Exploratorium filmed and broadcast live the total eclipse of the Sun as seen from Side, Turkey. The web site created around this event includes streaming video of the eclipse, a slide show from first contact through totality and fourth contact, and an image gallery with photos of the eclipse and the chosen site in Turkey, a Roman-era amphitheater. There is also information about how the location was chosen, a map showing the path of totality, how the eclipse was filmed and broadcast live by satellite, and the mechanics of a solar eclipse.

2006-02-23

306

Total body calcium analysis. [neutron irradiation  

NASA Technical Reports Server (NTRS)

A technique to quantitate total body calcium in humans is developed. Total body neutron irradiation is utilized to produce argon 37. The radio argon, which diffuses into the blood stream and is excreted through the lungs, is recovered from the exhaled breath and counted inside a proportional detector. Emphasis is placed on: (1) measurement of the rate of excretion of radio argon following total body neutron irradiation; (2) the development of the radio argon collection, purification, and counting systems; and (3) development of a patient irradiation facility using a 14 MeV neutron generator. Results and applications are discussed in detail.

Lewellen, T. K.; Nelp, W. B.

1974-01-01

307

Loose Metasul liner causing partial amputation of the neck of the femoral component.  

PubMed

The use of metal-on-metal bearings in total hip arthroplasty is becoming increasingly popular. Several authors have reported excellent medium- and long-term results after the use of the Metasul metal-on-metal articulation (Sulzer Medica, Winterthur, Switzerland). We report a case of a loose Metasul liner eroding the neck of the femoral component resulting in extensive metallosis and weakening of the prosthesis. PMID:18534444

McMurtrie, Andrew; Guha, Abhijit R; Wootton, James R

2009-01-01

308

Combinatorics related to the totally nonnegative Grassmannian  

E-print Network

In this thesis we study the combinatorial objects that appear in the study of nonnegative part of the Grassmannian. The classical theory of total positivity studies matrices such that all minors are nonnegative. Lustzig ...

Oh, SuHo

2011-01-01

309

Total Building Air Management: When Dehumidification Counts  

E-print Network

, total air management of sensible and latent heat, filtration and zone pressure was brought about through the implementation of non-integrated, composite systems. Composite systems typically are built up of multi-vendor equipment each of which perform...

Chilton, R. L.; White, C. L.

1996-01-01

310

Total synthesis and structural revision of hericerin.  

PubMed

The total synthesis of hericerin, a pollen growth inhibitor from Hericium erinaceum, was achieved. We found that the reported structure of hericerin should be revised to be the carbonyl regioisomer. PMID:22670711

Kobayashi, Shoji; Inoue, Tomoharu; Ando, Ami; Tamanoi, Hidetsugu; Ryu, Ilhyong; Masuyama, Araki

2012-07-01

311

Total synthesis and study of myrmicarin alkaloids  

E-print Network

I. Enantioselective Total Synthesis of Tricyclic Myrmicarin Alkaloids An enantioselective gram-scale synthesis of a key dihydroindolizine intermediate for the preparation of myrmicarin alkaloids is described. Key transformations ...

Ondrus, Alison Evelynn, 1981-

2009-01-01

312

Total synthesis of cyclotryptamine and diketopiperazine alkaloids  

E-print Network

I. Total Synthesis of the (+)-12,12'-Dideoxyverticillin A The fungal metabolite (+)-12,12'-dideoxyverticillin A, a cytotoxic alkaloid isolated from a marine Penicillium sp., belongs to a fascinating family of densely ...

Kim, Justin, Ph. D. Massachusetts Institute of Technology

2013-01-01

313

Total Synthesis of the Proposed Banyasin A  

NASA Astrophysics Data System (ADS)

The first total synthesis of four possible isomers of a molecule possessing the stereochemistry proposed for banyasin A is described. The structure synthesized appears to be different from that of the natural product.

Gao, Xuguang; Ren, Qi; Choi, Sun; Xu, Zhengshuang; Ye, Tao

2015-03-01

314

The first total synthesis of (+/-)-apparicine.  

PubMed

The first total synthesis of the indole alkaloid apparicine has been developed through a sequence that includes an indole-templated ring-closing metathesis and a vinyl halide Heck cyclization. PMID:19503874

Bennasar, M-Lluďsa; Zulaica, Ester; Solé, Daniel; Alonso, Sandra

2009-06-21

315

Total Solar Eclipse--A Caribbean Adventure.  

ERIC Educational Resources Information Center

Describes the experiences of two high school students who traveled to the Caribbean island of Curacao to view a total solar eclipse and prepare methods for teaching classmates about the eclipse the following school year. (Author/WRM)

Green, Steven; Tunstall, Louisa; Tunstall, Neil

1999-01-01

316

UNDERSTANDING CHILDREN'S TOTAL DIETARY EXPOSURE TO PESTICIDES  

EPA Science Inventory

Recent residential monitoring studies have demonstrated that significant portion of total exposure of infants and children to environmental contaminants can result from contamination of food in the home. Children's foods become contaminated through handling and contact with surf...

317

Macrolide Synthesis Total Synthesis of Phorboxazole A**  

E-print Network

Macrolide Synthesis Total Synthesis of Phorboxazole A** David R. Williams,* Andre A. Kiryanov­5 for the convergent assembly of the target macrolide (Scheme 1). Stereoselective formation of the C22­C26

Williams, David R.

318

Enantioselective Total Synthesis of (?)-Acylfulvene and (?)- Irofulven  

E-print Network

We report our full account of the enantioselective total synthesis of (?)-acylfulvene (1) and (?)-irofulven (2), which features metathesis reactions for the rapid assembly of the molecular framework of these antitumor ...

Movassaghi, Mohammad

319

Need total sulfur content? Use chemiluminescence  

SciTech Connect

Regulations issued by the United States Environmental Protection Agency require petroleum refineries to reduce or control the amount of total sulfur present in their refined products. These legislative requirements have led many refineries to search for online instrumentation that can produce accurate and repeatable total sulfur measurements within allowed levels. Several analytical methods currently exist to measure total sulfur content. They include X-ray fluorescence (XRF), microcoulometry, lead acetate tape, and pyrofluorescence techniques. Sulfur-specific chemiluminescence detection (SSCD) has recently received much attention due to its linearity, selectivity, sensitivity, and equimolar response. However, its use has been largely confined to the area of gas chromatography. This article focuses on the special design considerations and analytical utility of an SSCD system developed to determine total sulfur content in gasoline. The system exhibits excellent linearity and selectivity, the ability to detect low minimum levels, and an equimolar response to various sulfur compounds. 2 figs., 2 tabs.

Kubala, S.W.; Campbell, D.N. [Fluid Data, Inc., Angleton, TX (United States); DiSanzo, F.P. [Mobil Technology Co., Paulsboro, NJ (United States)

1996-09-01

320

TOTAL REFLUX OPERATION OF MULTIVESSEL BATCH DISTILLATION  

E-print Network

TOTAL REFLUX OPERATION OF MULTIVESSEL BATCH DISTILLATION BERND WITTGENS, RAJAB LITTO, EVA SŘRENSEN in this paper provides a generalization of previously proposed batch distillation schemes. A simple feedback been built and the experiments verify the simulations. INTRODUCTION Although batch distillation

Skogestad, Sigurd

321

A Formal Total Synthesis of (?)-Brevisamide  

PubMed Central

A formal total synthesis of (?)-brevisamide has been achieved. The synthetic approach highlights a chemoselective asymmetric dihydroxylation and a one-pot Fraser-Reid epoxidation/PMB protection reaction sequence. PMID:21572531

Smith, Amos B.; Kutsumura, Noriki; Potuzak, Justin

2011-01-01

322

EVALUATION OF THE TECHNICON BLOCK DIGESTOR SYSTEM FOR TOTAL KJELDAHL NITROGEN AND TOTAL PHOSPHORUS  

EPA Science Inventory

Technicon's block digestor method for the simultaneous determination of total phosphorus and total Kjeldahl nitrogen has been evaluated and modified for the semi-automated determination of these constituents in surface water and domestic and industrial wastes. The Technicon diges...

323

Total variation diminishing Runge-Kutta schemes  

Microsoft Academic Search

In this paper we further explore a class of high order TVD (total variation diminishing) Runge-Kutta time discretization initialized in a paper by Shu and Osher, suitable for solving hyperbolic conservation laws with stable spatial discretizations. We illustrate with numerical examples that non-TVD but linearly stable Runge-Kutta time discretization can generate oscillations even for TVD (total variation diminishing) spatial discretization,

Sigal Gottlieb; Chi-wang Shu

1998-01-01

324

Total synthesis of leucosceptroids A and B.  

PubMed

Leucosceptroids?A and B are sesterterpenoids with potent antifeedant and antifungal activities. A more efficient gram-scale total synthesis of leucosceptroid?B and the first total synthesis of leucosceptroid?A are presented. The key transformations include an aldol reaction between a substituted dihydrofuranone and an (S)-citronellal-derived aldehyde, a SmI2-mediated intramolecular ketyl-olefin radical cyclization, and final-stage alcohol oxidation. PMID:25470240

Guo, Sheng; Liu, Jie; Ma, Dawei

2015-01-19

325

Cogeneration Plant is Designed for Total Energy  

E-print Network

character istics and performance of a 200 MW combined cycle cogeneration plant located at Occidental Chemical Corporation's Battleground chlorine-caustic plant at La Porte, Texas. This successful application of a total energy management concept... plant at La Porte, Texas, produces chlorine, caustic soda, and hydrogen by an energy-intensive electro chemical process. Approximately 50% of the total manufacturing cost is attributed to energy costs. In order to maintain or improve its competitive...

Howell, H. D.; Vera, R. L.

326

Effects of xenobiotics on total antioxidant capacity  

PubMed Central

The objective of this article was to review the effects of xenobiotics on total antioxidant capacity (TAC). Measurement of TAC is appropriate for evaluation of the total antioxidant defenses of blood, cells, and different kinds of tissues and organs. TAC is reduced by alcoholism, smoking, and exposure to radiation, herbicides, carbon monoxide, carbon tetrachloride, lead, arsenic, mercury, cadmium, aluminum, and other toxic elements. The test is also an important tool in evaluating environmental and occupational exposure. PMID:23554550

2012-01-01

327

Total colectomy, mucosal proctectomy, and ileoanal anastomosis  

Microsoft Academic Search

A safe and practical procedure for total colectomy and mucosal proctectomy with ileonal anastomosis has been developed and\\u000a performed by us on 11 patients with adenomatosis coli and two patients with ulcerative colitis. The major features of the\\u000a operative procedure are 1) total removal of the rectal mucosa to just above the dentate line; 2) preservation of anorectal\\u000a function by

J. Utsunomiya; T. Iwama; M. Imajo; S. Matsuo; S. Sawai; K. Yaegashi; R. Hirayama

1980-01-01

328

Rising Total Hadron-Hadron Cross Sections  

E-print Network

A historical summary is made on the measurements concerning the rising total hadron-hadron cross sections at high energies. The first part of this paper concerns the total cross section measurements performed at the Brookhaven, Serpukhov and Fermilab fixed target accelerators; then the measurements at the CERN Intersecting Storage Rings (ISR), and at the CERN and at the Tevatron Fermilab proton-antiproton colliders; finally the cosmic ray measurements at even higher energies. A short discussion on Conclusions and Perspectives follows.

Giorgio Giacomelli

2007-12-06

329

1-Voluntariado Local Curso 2009-2010 Mujeres Hombres Total Mujeres Hombres Total  

E-print Network

1-Voluntariado Local Curso 2009-2010 Mujeres Hombres Total Mujeres Hombres Total Ambiental 29 17 46 con discapacidad 1 2 3 0 0 0 Apoyo e integraciĂłn escolar 1 2 3 1 1 2 TOTAL VOLUNTARIADO LOCAL 74 36 de la Salud 0 0 0 0 23 23 Rama Desconocida 0 0 0 0 0 0 No estudiante 1 1 0 0 5 7 TOTAL VOLUNTARIADO

Autonoma de Madrid, Universidad

330

TOTAL MUJERES TOTAL MUJERES ESCUELA POLITCNICA SUPERIOR 26 4 64 19 90 23  

E-print Network

TOTAL MUJERES TOTAL MUJERES ESCUELA POLITĂ?CNICA SUPERIOR 26 4 64 19 90 23 CIENCIAS 160 81 169 106 133 78 80 60 213 138 PSICOLOGĂŤA 84 72 108 90 192 162 TOTAL CENTROS PROPIOS 1.480 953 1.101 685 2.581 1 HIERRO 0 0 1 1 1 1 E.U. DE FISIOTERAPIA DE LA ONCE. 0 0 0 0 0 0 TOTAL CENTROS ADSCRITOS 32 29 28 25 60 54

Autonoma de Madrid, Universidad

331

1-Voluntariado Local Curso 2008-2009 Mujeres Hombres Total Mujeres Hombres Total  

E-print Network

1-Voluntariado Local Curso 2008-2009 Mujeres Hombres Total Mujeres Hombres Total Ambiental 32 19 51 con discapacidad 2 5 7 2 1 3 Apoyo e integraciĂłn escolar 6 0 6 4 0 4 TOTAL VOLUNTARIADO LOCAL 80 42 de la Salud 0 1 1 0 21 23 Rama Desconocida 1 0 0 0 0 1 TOTAL VOLUNTARIADO LOCAL 51 23 7 6 35 122

Autonoma de Madrid, Universidad

332

Improved survival for anatomic total shoulder prostheses  

PubMed Central

Background and purpose Previously, implant survival of total shoulder prostheses was reported to be inferior to that of hemiprostheses. However, the use of total prostheses has increased in Norway due to reported good functional results. On this background, we wanted to study implant survival of 4 major shoulder prosthesis types in Norway between 1994 and 2012. Patients and methods The study population comprised 4,173 patients with shoulder replacements reported to the Norwegian Arthroplasty Register, including 2,447 hemiprostheses (HPs), 444 anatomic total prostheses (ATPs), 454 resurfacing prostheses (RPs), and 828 reversed total prostheses (RTPs). Three time periods were compared: 1994–1999, 2000–2005, and 2006–2012. Kaplan-Meier failure curves were used to compare implant failure rates for subgroups of patients, and adjusted risks of revision were calculated using Cox regression analysis. Results For prostheses inserted from 2006 through 2012, the 5-year survival rates were 95% for HPs (as opposed to 94% in 1994–1999), 95% for ATPs (75% in 1994–1999), 87% for RPs (96% in 1994–1999), and 93% for RTPs (91% in 1994–1999). During the study period, the implant survival improved significantly for ATPs (p < 0.001). A tendency of better results with acute fracture and worse results in sequelae after previous fractures was seen in all time periods. Interpretation The 5-year implant survival rates were good with all prosthesis types, and markedly improved for anatomic total prostheses in the last 2 study periods. The better functional results with total shoulder prostheses than with hemiprostheses support the trend towards increased use of total shoulder prostheses. PMID:25386737

Fevang, Bjřrg T S; Nystad, Tone W; Skredderstuen, Arne; Furnes, Ove N; Havelin, Leif I

2015-01-01

333

Predicting the Total Charm Cross Section  

SciTech Connect

We discuss the energy dependence of the total charm cross section and some of its theoretical uncertainties including the quark mass, scale choice and the parton densities. Extracting the total charm cross section from data is a non-trivial task. To go from a finite number of measured D mesons in a particular decay channel to the total c{bar c} cross section one must: divide by the branching ratio for that channel; correct for the luminosity, {sigma}{sub D} = N{sub D}/Lt; extrapolate to full phase space from the finite detector acceptance; divide by two to get the pair cross section from the single Ds; and multiply by a correction factor to account for unmeasured charm hadrons. Early fixed-target data were at rather low p{sub T}, making the charm quark mass the most relevant scale. At proton and ion colliders, although the RHIC experiments can access the full pT range and thus the total cross section, the data reach rather high p{sub T}, p{sub T} >> m, making p{sub T} (m{sub T}) the most relevant scale. Here we focus on the total cross section calculation where the quark mass is the only relevant scale.

Vogt, R

2008-05-29

334

A high performance totally ordered multicast protocol  

NASA Technical Reports Server (NTRS)

This paper presents the Reliable Multicast Protocol (RMP). RMP provides a totally ordered, reliable, atomic multicast service on top of an unreliable multicast datagram service such as IP Multicasting. RMP is fully and symmetrically distributed so that no site bears un undue portion of the communication load. RMP provides a wide range of guarantees, from unreliable delivery to totally ordered delivery, to K-resilient, majority resilient, and totally resilient atomic delivery. These QoS guarantees are selectable on a per packet basis. RMP provides many communication options, including virtual synchrony, a publisher/subscriber model of message delivery, an implicit naming service, mutually exclusive handlers for messages, and mutually exclusive locks. It has commonly been held that a large performance penalty must be paid in order to implement total ordering -- RMP discounts this. On SparcStation 10's on a 1250 KB/sec Ethernet, RMP provides totally ordered packet delivery to one destination at 842 KB/sec throughput and with 3.1 ms packet latency. The performance stays roughly constant independent of the number of destinations. For two or more destinations on a LAN, RMP provides higher throughput than any protocol that does not use multicast or broadcast.

Montgomery, Todd; Whetten, Brian; Kaplan, Simon

1995-01-01

335

Uncommon Indications for Reverse Total Shoulder Arthroplasty  

PubMed Central

Total shoulder arthroplasty and shoulder hemiarthroplasty have been the traditional method for treating a variety of shoulder conditions, including arthritis, cuff tear arthropathy, and some fracture types. However, these procedures did not provide consistently good results for patients with torn rotator cuffs. The development of the reverse prosthesis by Grammont in the late 20th century revolutionized the treatment of the rotator-cuff-deficient shoulder with arthritis. The main indication for the reverse prosthesis remains the patient with cuff tear arthropathy who has pain and loss of motion. Because the reverse total shoulder arthroplasty produced such good results in these patients, the indications for the reverse prosthesis have expanded to include other shoulder conditions that have previously been difficult to treat successfully and predictably. This review discusses and critically reviews these newer indications for the reverse total shoulder arthroplasty. PMID:24340143

Hyun, Yoon Suk; Huri, Gazi; Garbis, Nickolas G.

2013-01-01

336

Total Solar Eclipse of 1997 March 9  

NASA Technical Reports Server (NTRS)

A total eclipse of the Sun will be visible from Asia and the Pacific Ocean on 1997 March 9. The path of the Moon's umbral shadow begins in eastern Kazakhstan and travels through Mongolia and eastern Siberia, where it swings northward to end at sunset in the Arctic Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern Asia, the northern Pacific, and the northwest corner of North America. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 280 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

Espenak, Fred; Anderson, Jay

1995-01-01

337

Total Solar Eclipse of 2002 December 04  

NASA Technical Reports Server (NTRS)

On 2002 December 04, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and the Indian Ocean, and ends at sunset in southern Australia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the southern two thirds of Africa, Antarctica, Indian Ocean and Australia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 400 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

Espenak, Fred; Anderson, Jay

2001-01-01

338

The US 2017 Total Solar Eclipse Workshops  

NASA Astrophysics Data System (ADS)

In preparation for the Total Solar Eclipse that will span across the United States in 2017, multiple eclipse workshops are being planned to bring together professional and amateur researchers, educators, and imagers. Our ultimate goal with these workshops is to maximize the amount and quality of data we can collect during the eclipse as well as to leverage this exciting event to educate and inspire people of all ages. Part of the workshops will be dedicated to discussing the science that can be learned from observing total solar eclipses, and part of the workshops will be dedicated to strategizing about how to mobilize and prepare communities in the path of totality. In this poster, we will share our preliminary results from the inaugural workshop in Maryland, April 2012.

Arndt, Martina B.; Habbal, S. R.; Wind Sherpas, Solar

2012-05-01

339

Total Solar Eclipse of 2001 June 21  

NASA Technical Reports Server (NTRS)

On 2001 June 21, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and Madagascar, and ends at sunset in the Indian Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern South America and the southern two thirds of Africa. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 350 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

Espenak, Fred; Anderson, Jay

1999-01-01

340

Total body potassium in cor pulmonale.  

PubMed Central

Total body potassium was measured in 12 patients with cor pulmonale, by determination of potassium-40, a naturally occurring radioisotope. In all subjects the observed value of total body potassium showed no significant depletion when compared with that predicted from height and age. All previous studies in similar groups of patients have been confined to the estimation of exchangeable potassium by the technique of isotope dilution. Results using the latter technique have shown gross potassium depletion. It is suggested that the apparent disparity between total body potassium and exchangeable potassium could be explained by the requirement for a longer equilibration period when using isotope dilution techniques in patients who are in chronic hypoxaemic state. PMID:13510

Howie, A D; Pack, A I; Boddy, K; Mahaffey, M

1976-01-01

341

Imaging Total Stations - Modular and Integrated Concepts  

NASA Astrophysics Data System (ADS)

Keywords: 3D-Metrology, Engineering Geodesy, Digital Image Processing Initialized in 2009, the Institute for Spatial Information and Surveying Technology i3mainz, Mainz University of Applied Sciences, forces research towards modular concepts for imaging total stations. On the one hand, this research is driven by the successful setup of high precision imaging motor theodolites in the near past, on the other hand it is pushed by the actual introduction of integrated imaging total stations to the positioning market by the manufacturers Topcon and Trimble. Modular concepts for imaging total stations are manufacturer independent to a large extent and consist of a particular combination of accessory hardware, software and algorithmic procedures. The hardware part consists mainly of an interchangeable eyepiece adapter offering opportunities for digital imaging and motorized focus control. An easy assembly and disassembly in the field is possible allowing the user to switch between the classical and the imaging use of a robotic total station. The software part primarily has to ensure hardware control, but several level of algorithmic support might be added and have to be distinguished. Algorithmic procedures allow to reach several levels of calibration concerning the geometry of the external digital camera and the total station. We deliver insight in our recent developments and quality characteristics. Both the modular and the integrated approach seem to have its individual strengths and weaknesses. Therefore we expect that both approaches might point at different target applications. Our aim is a better understanding of appropriate applications for robotic imaging total stations. First results are presented. Stefan Hauth, Martin Schlüter i3mainz - Institut für Raumbezogene Informations- und Messtechnik FH Mainz University of Applied Sciences Lucy-Hillebrand-Straße 2, 55128 Mainz, Germany

Hauth, Stefan; Schlüter, Martin

2010-05-01

342

Failure of aseptic revision total knee arthroplasties  

PubMed Central

Background and purpose In Norway, the proportion of revision knee arthroplasties increased from 6.9% in 1994 to 8.5% in 2011. However, there is limited information on the epidemiology and causes of subsequent failure of revision knee arthroplasty. We therefore studied survival rate and determined the modes of failure of aseptic revision total knee arthroplasties. Method This study was based on 1,016 aseptic revision total knee arthroplasties reported to the Norwegian Arthroplasty Register between 1994 and 2011. Revisions done for infections were not included. Kaplan-Meier and Cox regression analyses were used to assess the survival rate and the relative risk of re-revision with all causes of re-revision as endpoint. Results 145 knees failed after revision total knee arthroplasty. Deep infection was the most frequent cause of re-revision (28%), followed by instability (26%), loose tibial component (17%), and pain (10%). The cumulative survival rate for revision total knee arthroplasties was 85% at 5 years, 78% at 10 years, and 71% at 15 years. Revision total knee arthroplasties with exchange of the femoral or tibial component exclusively had a higher risk of re-revision (RR = 1.7) than those with exchange of the whole prosthesis. The risk of re-revision was higher for men (RR = 2.0) and for patients aged less than 60 years (RR = 1.6). Interpretation In terms of implant survival, revision of the whole implant was better than revision of 1 component only. Young age and male sex were risk factors for re-revision. Deep infection was the most frequent cause of failure of revision of aseptic total knee arthroplasties. PMID:25267502

Leta, Tesfaye H; Lygre, Stein Hĺkon L; Skredderstuen, Arne; Hallan, Geir; Furnes, Ove

2015-01-01

343

An Operational Perspective of Total Lightning Information  

NASA Technical Reports Server (NTRS)

The close and productive collaborations between the NWS Warning and Forecast Office, the Short Term Prediction and Research Transition Center at NASA Marshall Space Flight Center and the University of Alabama in Huntsville have provided a unique opportunity for science sharing and technology transfer. One significant technology transfer that has provided immediate benefits to NWS forecast and warning operations is the use of data from the North Alabama Lightning Mapping Array. This network consists of ten VHF receivers deployed across northern Alabama and a base station located at the National Space Science and Technology Center. Preliminary investigations done at WFO Huntsville, along with other similar total lightning networks across the country, have shown distinct correlations between the time rate-of-change of total lightning and trends in intensity/severity of the parent convective cell. Since May 2003 when WFO HUN began receiving these data - in conjunction with other more traditional remotely sensed data (radar, satellite, and surface observations) -- have improved the situational awareness of the WFO staff. The use of total lightning information, either from current ground based systems or future space borne instrumentation, may substantially contribute to the NWS mission, by enhancing severe weather warning and decision-making processes. Operational use of the data has been maximized at WFO Huntsville through a process that includes forecaster training, product implementation, and post event analysis and assessments. Since receiving these data, over 50 surveys have been completed highlighting the use of total lightning information during significant events across the Tennessee Valley. In addition, around 150 specific cases of interest have been archived for collaborative post storm analysis. From these datasets, detailed trending information from radar and total lightning can be compared to corresponding damage reports. This presentation will emphasize the effective use of total lightning information in warning decision making along with best practices for implementation of new technologies into operations.

Nadler, David J.; Darden, Christopher B.; Stano, Geoffrey; Buechler, Dennis E.

2009-01-01

344

Total Knee Arthroplasty in Rheumatoid Arthritis  

PubMed Central

The course of rheumatoid arthritis varies from mild disease to severe joint destructive variant that progresses rapidly, eventually leading to unremitting pain and joint deformity. In advanced disease, total knee arthroplasty has proven to be the most successful intervention that reduces knee pain and improves physical function in rheumatoid arthritis patients. However, as rheumatoid arthritis patients carry additional potential for late complications, many important considerations regarding preoperative evaluation and surgical technique must be taken into account in order to improve the results of total knee arthroplasty in this subgroup of patients. PMID:22570845

Lee, Jin Kyu

2012-01-01

345

Gemella haemolysans Infection in Total Hip Arthroplasty  

PubMed Central

Gemella haemolysans is a Gram-positive coccus and commensal of the upper respiratory tract and oral mucosa that rarely causes clinically important infections. There is only one previous report of this organism causing periprosthetic infection, in a total knee arthroplasty. We present a case of septic loosening of an uncemented total hip arthroplasty due to G. haemolysans, in an asplenic patient with insulin dependent diabetes mellitus. Treatment with two-stage revision has been successful at 7 years of follow-up. PMID:23227390

Rose, Barry; Jeer, Parminder J. S.; Spriggins, Anthony J.

2012-01-01

346

Nucleon-Nucleon Total Cross Section  

NASA Technical Reports Server (NTRS)

The total proton-proton and neutron-proton cross sections currently used in the transport code HZETRN show significant disagreement with experiment in the GeV and EeV energy ranges. The GeV range is near the region of maximum cosmic ray intensity. It is therefore important to correct these cross sections, so that predictions of space radiation environments will be accurate. Parameterizations of nucleon-nucleon total cross sections are developed which are accurate over the entire energy range of the cosmic ray spectrum.

Norbury, John W.

2008-01-01

347

Total knee arthroplasty considerations in rheumatoid arthritis.  

PubMed

The definitive treatment for advanced joint destruction in the late stages of rheumatoid arthritis can be successfully treated with total joint arthroplasty. Total knee arthroplasty has been shown to be a well-proven modality that can provide pain relief and restoration of mobility for those with debilitating knee arthritis. It is important for rheumatologists and orthopedic surgeons alike to share an understanding of the special considerations that must be addressed in this unique population of patients to ensure success in the immediate perioperative and postoperative periods including specific modalities to maximize success. PMID:24151549

Danoff, Jonathan R; Moss, Garrett; Liabaud, Barthelemy; Geller, Jeffrey A

2013-01-01

348

Biomechanics of reverse total shoulder arthroplasty.  

PubMed

Reverse total shoulder arthroplasty is an effective procedure for treatment of glenohumeral joint disease among patients with severe rotator cuff deficiency. Improvements in prosthetic design are the result of an evolved understanding of both shoulder and joint replacement biomechanics. Although modern generations of the reverse shoulder prosthesis vary in specific design details, they continue to adhere to Grammont's core principles demonstrated by his original Delta III prosthesis. This review article discusses the biomechanics of reverse total shoulder arthroplasty with a focus on elements of implant design and surgical technique that may affect stability, postoperative complications, and functional outcomes. PMID:25441574

Berliner, Jonathan L; Regalado-Magdos, Ashton; Ma, C Benjamin; Feeley, Brian T

2015-01-01

349

Total Laparoscopic Hysterectomy Using the Harmonic Scalpel  

PubMed Central

Total laparoscopic hysterectomy (TLH) is the complete hysterectomy including transection of the uterine vessels and opening/closure of the vaginal vault performed laparoscopically. This procedure can be performed as an alternative to total abdominal hysterectomy in many cases. We previously found use of the harmonic scalpel to be extremely helpful in performing laparoscopically assisted vaginal hysterectomies. In this series, the harmonic scalpel was used to facilitate performing TLH. Our experience has shown this can be performed without major complications in a cost-effective manner. PMID:10527328

Mendelsohn, Susan A.

1999-01-01

350

Total Quantum Zeno Effect beyond Zeno Time  

E-print Network

In this work we show that is possible to obtain Total Quantum Zeno Effect in an unstable systems for times larger than the correlation time of the bath. The effect is observed for some particular systems in which one can chose appropriate observables which frequent measurements freeze the system into the initial state. For a two level system in a squeezed bath one can show that there are two bath dependent observables displaying Total Zeno Effect when the system is initialized in some particular states. We show also that these states are intelligent states of two conjugate observables associated to the electromagnetic fluctuations of the bath.

D. Mundarain; M. Orszag; J. Stephany

2007-04-12

351

Estimating total momentum at finite distances  

E-print Network

We study the difficulties associated with the evaluation of the total Bondi momentum at finite distances around the central source of a general (asymptotically flat) spacetime. Since the total momentum is only rigorously defined at future null infinity, both finite distance and gauge effects must be taken into account for a correct computation of this quantity. Our discussion is applicable in general contexts but is particularly relevant in numerically constructed spacetimes for both extracting important physical information and assessing the accuracy of additional quantities.

Emanuel Gallo; Luis Lehner; Osvaldo Moreschi

2008-09-25

352

Measuring Total and Germinable Spore Populations  

NASA Astrophysics Data System (ADS)

It has been shown that bacterial endospores can be enumerated using a microscopy based assay that images the luminescent halos from terbium ions bound to dipicolinic acid, a spore specific chemical marker released upon spore germination. Further development of the instrument has simplified it towards automation while at the same time improving image quality. Enumeration of total spore populations has also been developed allowing measurement of the percentage of viable spores in any population by comparing the germinable/culturable spores to the total. Percentage viability will allow a more quantitative comparison of the ability of spores to survive across a wide range of extreme environments.

Noell, A. C.; Yung, P. T.; Yang, W.; Ponce, A.; Lee, C.

2011-10-01

353

Total Knee Arthroplasty Considerations in Rheumatoid Arthritis  

PubMed Central

The definitive treatment for advanced joint destruction in the late stages of rheumatoid arthritis can be successfully treated with total joint arthroplasty. Total knee arthroplasty has been shown to be a well-proven modality that can provide pain relief and restoration of mobility for those with debilitating knee arthritis. It is important for rheumatologists and orthopedic surgeons alike to share an understanding of the special considerations that must be addressed in this unique population of patients to ensure success in the immediate perioperative and postoperative periods including specific modalities to maximize success. PMID:24151549

Danoff, Jonathan R.; Geller, Jeffrey A.

2013-01-01

354

Total ozone variations at Reykjavík since 1957  

NASA Astrophysics Data System (ADS)

Total ozone measurements using a Dobson spectrophotometer have been performed on a regular basis at Reykjavík (64°08'N, 21°54'W), Iceland, since 1957. The data set for the entire period of observations has been critically examined. Due to problems related to the calibration of the instrument the data record of ozone observations is divided into two periods in the following analysis (1957-1977 and 1977-1990). A statistical model was developed to fit the data and estimate long-term changes in total ozone. The model includes seasonal variations, solar cycle influences, quasi-biennial oscillation (QBO) effects, and linear trends. Some variants of the model are applied to investigate to what extent the estimated trends depend on the form of the model. Trend analysis of the revised data reveals a statistically significant linear decrease of 0.11 ± 0.07% per year in the annual total ozone amount during the earlier period and 0.30 ± 0.11% during the latter. The annual total ozone decline since 1977 is caused by a 0.47 ± 0.14% decrease per year during the summer with no significant change during the winter or fall. On an annual basis, ozone varies by 3.5 ± 0.8% over a solar cycle and by 2.1 ± 0.6% over a QBO for the whole observation period. The effect of the 11-year solar cycle is particularly strong in the data during the early months of the year and in the westerly phase of the QBO. The data also suggest a strong response of total ozone to major solar proton events. Comparisons of the total ozone data made at Reykjavík during the last 13 years with total ozone as measured by the total ozone mapping spectrometer (TOMS) on the Nimbus 7 satellite show an excellent agreement for solar zenith angles less than 80° at times of satellite overpass. Comparisons with results of the zonally averaged TOMS data at this latitude suggest a significant longitudinal dependence of the linear trends in stratospheric ozone. This is in accordance with recent analysis of the satellite data.

Bjarnason, Gudmundur G.; RöGnvaldsson, Örnólfur E.; Sigfússon, Thorsteinn I.; Jakobsson, Thor; Thorkelsson, Bardi

1993-12-01

355

Data on total and spectral solar irradiance  

NASA Technical Reports Server (NTRS)

This paper presents a brief survey of the data available on solar constant and extraterrestrial solar spectral irradiance. The spectral distribution of solar radiation at ground surface, computed from extraterrestrial solar spectral irradiance for several air mass values and for four levels of atmospheric pollution, is also presented. The total irradiance at ground level is obtained by integration of the area under the spectral irradiance curves. It is significant that, as air mass increases or as turbidity increases, the amount of energy in the infrared relative to the total increases and that the energy in the UV and visible decreases.

Mecherikunnel, A. T.; Gatlin, J. A.; Richmond, J. C.

1983-01-01

356

Job Title BIOLOGY GENETICS MICRO TOX TOTAL BIOLOGY GENETICS MICRO TOX TOTAL BIOLOGY GENETICS MICRO TOX TOTAL T/TT Faculty  

E-print Network

Job Title BIOLOGY GENETICS MICRO TOX TOTAL BIOLOGY GENETICS MICRO TOX TOTAL BIOLOGY GENETICS MICRO.00 Job Title NTT Faculty BIOLOGY GENETICS MICRO TOX TOTAL BIOLOGY GENETICS MICRO TOX TOTAL BIOLOGY GENETICS MICRO TOX TOTAL Lecturer 3.76 2.00 5.76 3.76 2.00 - - 5.76 Teaching Asst Professor 8.57 2.00 10

Liu, Paul

357

The technology behind Colgate Total Advanced Fresh.  

PubMed

In the early 1990s, a breakthrough toothpaste, Colgate Total, was launched with documented long-lasting activity against plaque, gingivitis, calculus, tooth decay, and bad breath. The technology behind this toothpaste is the combination of triclosan, a polyvinylmethylether/maleic acid copolymer, and sodium fluoride. The copolymer ensures maximal oral retention and subsequent release of the antibacterial triclosan. Effective levels of triclosan have been observed in the oral cavity 12 hours after brushing the teeth, allowing prolonged control of oral bacteria that may cause the most common dental problems, including bad breath. Similarly, the enhanced retention of triclosan to oral surfaces after using this revolutionary toothpaste for up to 2 years has led to significantly reduced incremental coronal caries compared to an American Dental Association-Approved anticavity fluoride toothpaste. Furthermore, significantly less calcium remained in dental plaque after brushing the teeth with the triclosan/copolymer toothpaste, resulting in the formation of less tartar. In keeping with the multiple oral health benefits provided by Colgate Total, consumers are now offered a new dentifrice, Colgate Total Advanced Fresh, which provides the numerous therapeutic and esthetic benefits that are the hallmark of Colgate Total. The new dentifrice, which contains an impactful breath-freshening flavor, has been documented to provide sustained control of bad breath over 12 hours. PMID:14692205

Williams, Malcolm I; Cummins, Diane

2003-09-01

358

On the Total Variation Dictionary Model  

Microsoft Academic Search

The goal of this paper is to provide a theoretical study of a total variation (TV) dictionary model. Based on the properties of convex analysis and bounded variation functions, the existence of solutions of the TV dictionary model is proved. We then show that the dual form of the model can be given by the minimization of the sum of

Tieyong Zeng; Michael K. Ng

2010-01-01

359

Trends to equilibrium in total variation distance  

Microsoft Academic Search

This paper presents different approaches, based on functional inequalities,\\u000ato study the speed of convergence in total variation distance of ergodic\\u000adiffusion processes with initial law satisfying a given integrability\\u000acondition. To this end, we give a general upper bound \\

Patrick Cattiaux; Arnaud Guillin

2009-01-01

360

Compound Poisson approximation in total variation  

Microsoft Academic Search

Poisson approximation in total variation can be successfully established in a wide variety of contexts, involving sums of weakly dependent random variables which usually take the value 0, and occasionally the value 1. If the random variables can take other positive integer values, or if there is stronger dependence between them, compound Poisson approximation may be more suitable. Stein's method,

A. D. Barbour; Sergey Utev

1999-01-01

361

Total variation error bounds for geometric approximation  

Microsoft Academic Search

We develop a new formulation of Stein's method to obtain computable upper bounds on the total variation distance between the geometric distribution and a distribution of interest. Our framework reduces the problem to the construction of a coupling between the original distribution and the \\

Erol Peköz; Adrian Röllin; Nathan Ross

2010-01-01

362

Total exchangeable potassium in response to amiloride  

Microsoft Academic Search

The use of amiloride is described in twenty-four hypertensive patients who became hypokalaemic as a result of thiazide diuretic therapy in spite of oral potassium supplments. Amiloride caused a significant rise in exchangeable potassium, exchangeable potassium\\/kg body weight, and plasma potassium, together with a significant fall in plasma total carbon dioxide, body weight, systolic and diastolic blood pressures. These results

V. R. Pearce; A. C. Antcliff; D. G. Beevers

1978-01-01

363

Total syntheses of lyconadins A-C.  

PubMed

The total synthesis of the Lycopodium alkaloid lyconadin A was accomplished and it was applied to the total syntheses of the related congeners, lyconadins B and C. Lyconadin A has attracted attention as a challenging target for total synthesis due to the unprecedented pentacyclic skeleton. Our synthesis of lyconadin A features a facile construction of the highly fused tetracyclic skeleton through a combination of an aza-Prins reaction and an electrocyclic ring opening, followed by formation of a C-N bond. Transformation of the bromoalkene moiety of the tetracycle to a key enone intermediate was extensively investigated, and three methods via sulfide, oxime, or azide intermediates were established. A pyridone ring was constructed from the key enone intermediate to complete the synthesis of lyconadin A. A dihydropyridone ring could also be formed from the same enone intermediate, leading to a synthesis of lyconadin B. Establishment of the conditions for an electrocyclic ring opening without formation of the C-N bond resulted in completion of the total synthesis of lyconadin C. PMID:23330605

Nishimura, Takuya; Unni, Aditya K; Yokoshima, Satoshi; Fukuyama, Tohru

2013-02-27

364

Total synthesis of (±)-hippolachnin?a.  

PubMed

The first total synthesis of the marine polyketide (±)-hippolachnin?A has been achieved in nine linear steps and an overall yield of 9?%. Rapid access to the oxacyclobutapentalene core structure was secured by strategic application of an ene cyclization. PMID:25476132

Ruider, Stefan A; Sandmeier, Tobias; Carreira, Erick M

2015-02-16

365

Enantiospecific total synthesis of macrolactone Sch 725674.  

PubMed

The enantiospecific total synthesis of 14-membered macrolactone Sch 725674 was accomplished from tartaric acid. Key reactions in the synthesis include the Ley's dithiaketalization of an alkynone derived from the bis-Weinreb amide of tartaric acid, Boord olefination, and ring-closing metathesis of an acrylate ester. PMID:25033232

Bali, Amit K; Sunnam, Sunil K; Prasad, Kavirayani R

2014-08-01

366

The Leica TCRA1105 Reflectorless Total Station  

SciTech Connect

This poster provides an overview of SLAC's TCRA1105 reflectorless total station for the Alignment Engineering Group. This instrument has shown itself to be very useful for planning new construction and providing quick measurements to difficult to reach or inaccessible surfaces.

Gaudreault, F.

2005-09-06

367

Totally geodesic surfaces in hyperbolic 3-manifolds  

E-print Network

closed embedded totally geodesic surfaces. v #12;Contents Acknowledgments iv Abstract v List of Figures On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 2.2 An internal face of Pn . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3 A cross Geodesic Faces of Na and Nb . . . . . . . . . . . . . . . . . 68 3.5 Closed Cusp of Nb

DeBlois, Jason

368

Total Laparoscopic Hysterectomy for Large Uterus  

PubMed Central

Aim: In this review, we assessed the feasibility of total laparoscopic hysterectomy (TLH) in cases of very large uteri weighing more than 500 grams. We have analyzed whether it is possible for an experienced laparoscopic surgeon to perform efficient total laparoscopic hysterectomy for large myomatous uteri regardless of the size, number and location of the myomas. Design: Retrospective review (Canadian Task Force Classification II-1) Setting: Dedicated high volume Gynecological laparoscopy centre. Patients: 173 women with symptomatic myomas who underwent total laparoscopic hysterectomy at our center. There were no exclusion criteria based on the size number or location of myomas. Intervention: TLH and modifications of performing the surgery by ligating the uterine arteries prior, myomectomy followed by hysterectomy, direct morcellation after uterine artery ligation. Results: 72% of patients had previous normal vaginal delivery and 28% had previous cesarean section. Average clinical size of the uterus was 18 weeks (10, 32). The average weight of the specimen was 700 grams (500, 2240). The average duration of surgery was 107 min (40, 300) and the average blood loss was 228 ml (10, 3200). Conclusion: Total laparoscopic hysterectomy is a technically feasible procedure. It can be performed by experienced surgeons for large uteri regardless of the size, number or location of the myomas. PMID:22442509

Sinha, Rakesh; Sundaram, Meenakshi; Lakhotia, Smita; Mahajan, Chaitali; Manaktala, Gayatri; Shah, Parul

2009-01-01

369

Revitalizing Space Operations through Total Quality Management  

NASA Technical Reports Server (NTRS)

The purpose of this paper is to show the reader what total quality management (TQM) is and how to apply TQM in the space systems and management arena. TQM is easily understood, can be implemented in any type of business organization, and works.

Baylis, William T.

1995-01-01

370

Application of Total Quality Management in Education  

ERIC Educational Resources Information Center

The purpose of the paper is to analyzing thoughts of the modern management paradigm "Total Quality Management" (TQM), and its application in the field of education. The basic theme of TQM is participatory approach to address the question(s) of quality in business aswell as in the field of education. Reviewing fresh literature from the internet …

Farooq, M. S.; Akhtar, M. S.; Ullah, S. Zia; Memon, R. A.

2007-01-01

371

First total synthesis of (-)-sinularianin B.  

PubMed

The first enantioselective total synthesis of (-)-sinularianin B, a structurally unique sesquiterpenoid isolated from the Formosan soft coral Sinularia sp., has been accomplished in 16 steps with 39.5% overall yield. Key transformations include formation of a cyclopentane possessing a tertiary hydroxy group via a tandem intermolecular-intramolecular alkylation involving a 5-endo cyclization. PMID:23877353

Ota, Koichiro; Miyaoka, Hiroaki

2013-09-25

372

Total Quality Management: Implications for Higher Education.  

ERIC Educational Resources Information Center

This book contains 19 papers describing the implementation of Total Quality Management in a variety of higher education settings. Following a Foreword by Peter Likins and a Preface by Daniel J. Julius, the chapter titles and authors are: (1) "TQM: Implications for Higher Education--A Look Back to the Future" (Allan M. Hoffman and Randall Summers);…

Hoffman, Allan M., Ed.; Julius, Daniel J., Ed.

373

[Difficult cases of total knee arthroplasty].  

PubMed

We report two difficult cases in total knee arthroplasty (TKA). One is an arthritis mutilans knee with large tibial bone deficiency that required TKA using tibial metal wedge augmentation. Another is a post-traumatic OA knee with varus deformity and rotational malalignment that had TKA by the ROBODOC system. PMID:15577088

Takagi, Hideki; Hirose, Kazuyoshi; Iwata, Hisashi

2004-07-01

374

Helping Students Discover Total Internal Reflection  

NSDL National Science Digital Library

Students learn the basic relationship of Snell's Law, practice applying it to a situation, then are given another situation where it "doesn't work."??? This situation turns out to be one in which total internal reflection occurs. Students are then shown what happens with classroom apparatus.

Kathleen Harper

375

Enantioselective total synthesis of (-)-xialenon A.  

PubMed

The first total synthesis of (-)-xialenon A (1) via conjugate allylation of a 1,5-cyclooctadiene-derived bicyclo[3.3.0]octenone 3 and an alpha'-hydroxylation on the more hinderd face of enone 9 using hypervalent iodine chemistry, is described. PMID:12430478

Hodgson, David M; Galano, Jean-Marie; Christlieb, Martin

2002-10-21

376

Coordinating Council. Ninth Meeting: Total Quality Management  

NASA Technical Reports Server (NTRS)

This report summarizes the 9th meeting of the STI Coordinating Council. The council listened to the speakers' understanding of Total Quality Management (TQM) principles and heard stories of successful applications of these principles. Definitions of quality stated were focused on customer satisfaction. Reports presented by the speakers are also included.

1992-01-01

377

Total Quality Management (TQM) in Higher Education.  

ERIC Educational Resources Information Center

This document consists largely of paper versions of the transparencies used by the author to give his conference paper on Total Quality Management (TQM) in the college and university setting. An introduction lists a series of definitional phrases, a list of what TQM is not, and 11 fundamental principles describing what TQM is. The three major…

Sullivan, Michael F.

378

Total Quality Management in Libraries: A Sourcebook.  

ERIC Educational Resources Information Center

Total Quality Management (TQM) brings together the best aspects of organizational excellence by driving out fear, offering customer-driven products and services, doing it right the first time by eliminating error, and maintaining inventory control without waste. Libraries are service organizations which are constantly trying to improve service.…

O'Neil, Rosanna M., Comp.

379

The Total Solar Eclipse, March 1970  

ERIC Educational Resources Information Center

Describes the circumstances of the total and partial solar eclipse of March 7, 1970 in certain American cities. Also discussed are (1) a classroom demonstration of the cause of solar eclipses, (2) techniques for safely observing the eclipse, and (3) what to observe during the eclipse. Bibliography. (LC)

Glenn, William H.

1970-01-01

380

COHYST 2010 A Total Water Budget  

E-print Network

1 COHYST 2010 A Total Water Budget Approach to Integrated Water Management Greater Platte River Basins Symposium October 7, 2010 Doug Hallum, P.G., Integrated Water Management Coordinator Nebraska Nebraska Public Power & Irrigation District Nebraska Public Power District Nebraska Game & Parks

Nebraska-Lincoln, University of

381

ON DEVELOPMENT OF TOTALLY IMPLANTABLE VESTIBULAR PROSTHESIS  

E-print Network

ON DEVELOPMENT OF TOTALLY IMPLANTABLE VESTIBULAR PROSTHESIS Andrei M. Shkel 1 Department vestibular prosthesis. The sensing element of the prosthesis is a custom designed one-axis MEMS gyroscope of the prosthesis on a rate table indicate that the device's output matches the average firing rate of vestibular

Tang, William C

382

Total Energy Management for Minnesota Schools.  

ERIC Educational Resources Information Center

Total Energy Management (TEM) is a unified, planned approach to reducing the energy use and costs of an individual school or school district. The program increases energy awareness and improves school energy efficiency through: (1) careful energy accounting; (2) changes in operations and maintenance procedures; (3) modifications in the building…

Minnesota State Dept. of Energy, Planning and Development, St. Paul.

383

Isolation of total RNA from pollens.  

PubMed

Isolation of total RNA from plant materials has been difficult, due to the presence of complex organic substances and the associated pigmentation. In fact, there is a dearth of standardized protocols for isolating total RNA from pollens. To find a simple and reliable method for isolating total RNA from pollen, four methods, viz. phenol/SDS (PS), guanidine HCl (GH), tri-reagent (TR), and modified SDS-betaME (SB) were tested with fresh pollen of Ricinus communis (procured at -70 degrees C) and pollen dried at 30-37 degrees C. The quality and quantity of RNA was superior for the material processed at -70 degrees C. SB gave the highest RNA yield (2.35 mg/g, OD260/280 >2.0), compared to other methods. The results obtained by the SB method were found to be comparable with the widely used tri-reagent method. This was validated with other pollens of Imperata cylindrica and Xanthium strumarium. The yield obtained from graded amounts of pollen was consistent with SB, compared to the TR method. The RNA isolated by SB gave good quality mRNA for synthesizing cDNA. The SDS-betaME method is simple, efficient, and uses less expensive reagents. Hence, we recommend the modified SDS-betaME method for isolating total RNA from pollens. PMID:11426703

Bijli, K M; Singh, B P; Sridhara, S; Arora, N

2001-05-01

384

Participation in Sports After Total Knee Replacement  

Microsoft Academic Search

Return to regular sports activity was evaluated in a retrospective review of 160 patients who had undergone total knee replacement surgery by a single surgeon (208 knee replacements). Mean age of the patients was 68 years (range, 27 to 87) at surgery and 73 years (range, 33 to 91) at review at a mean follow-up of 5 years (range, 3

Neil Bradbury; David Borton; Geoff Spoo; Mervyn J. Cross

1998-01-01

385

Total Synthesis of (+)-Condylocarpine, (+)-Isocondylocarpine, and (+)Tubotaiwine  

PubMed Central

The first enantioselective total syntheses of indolealk aloids of the condylocarpine type are reported. (+)-Condylocarpine, (+)-isocondylocarpine, and (+)-tubotaiwine were prepared in high enantiomeric purity (er >99:1) from (1 S,5 R)-hexahydro-1,5-methano-1 H-azocino[4,3 -b]indole-12-one 7b by way of five or six isolated intermediates. PMID:21133399

Martin, Connor L.; Nakamura, Seiichi; Otte, Ralf; Overman, Larry E.

2010-01-01

386

Total Synthesis of (±)-7-epi-Nemorosone  

PubMed Central

A concise total synthesis of (±)-7-epi-nemorosone is reported. Our synthetic approach establishes a viable route to polycyclic polyprenylated acylphloroglucinol natural products (PPAP’s) bearing a C-7 endo prenyl sidechain. Key steps include retro-aldol-vinyl cerium addition to a hydroxy adamantane core scaffold and palladium-mediated deoxygenation. PMID:22449198

Zhang, Qiang; Porco, John A.

2012-01-01

387

Total Quality Management: Institutional Research Applications.  

ERIC Educational Resources Information Center

Total Quality Management (TQM), a technique traditionally reserved for the manufacturing sector, has recently spread to service companies, government agencies, and educational institutions. TQM places responsibility for quality problems with management rather than on the workers. A principal concept of TQM is the management of Process Variation,…

Heverly, Mary Ann

388

Total Solar Eclipse of October, 1995  

NSDL National Science Digital Library

This page provides images of the total solar eclipse of October 24, 1995. The photographs were produced by Fred Espenak while in Dundlod, India. The site includes links to additional images and video footage of the eclipse including those of Dr. Shadia Habbal of the Harvard-Smithsonian Center for Astrophysics and the Japanese spacecraft, Yohkoh.

389

Nonlinear total variation based noise removal algorithms  

Microsoft Academic Search

A constrained optimization type of numerical algorithm for removing noise from images is presented. The total variation of the image is minimized subject to constraints involving the statistics of the noise. The constraints are imposed using Lagrange multipliers. The solution is obtained using the gradient-projection method. This amounts to solving a time dependent partial differential equation on a manifold determined

Leonid I. Rudin; Stanley Osher; Emad Fatemi

1992-01-01

390

Total Quality Management Initiatives in Higher Education.  

ERIC Educational Resources Information Center

Examines trends affecting higher education such as declining enrollments, replacement of faculty, rising costs, competition for enrollments, corporate education, work changes, and greater accountability and relates them to Total Quality Management (TQM). Relevant organizations, the role of leadership, and barriers to greater acceptance are…

Sullivan, Maureen; Siggins, Jack A.

1993-01-01

391

Rock around Tahoe Total Time: 25 Minutes  

E-print Network

Rock around Tahoe Total Time: 25 Minutes Objectives Students will: 1. Get a sense of the rock cycle as a continuing process. 2. Explore Tahoe examples of the rock cycle in action. Background Like most Earth materials, rocks are created and destroyed in cycles. The rock cycle is a model that describes the ongoing

Schladow, S. Geoffrey

392

Gender by Faculty Faculty Female Male Total  

E-print Network

Gender Gender by Faculty Faculty Female Male Total Humanities and Social Sciences 287 50.4% 283 49-represented in the School of Medicine and Dentistry (SMD) and in Professional Services. Gender by Employment Category related and Administrative roles. They are under-represented in Academic roles (33%). Queen Mary

Roelleke, Thomas

393

Total Quality Management. ERIC Digest, Number 73.  

ERIC Educational Resources Information Center

The Japanese success story has made W. Edwards Deming's Total Quality Management (TQM) theory increasingly popular among American managers, from car manufacturers to educational leaders. TQM is based on two tenets: the primacy of customer satisfaction and the necessity of tapping nontraditional sources (especially employee ideas) to institute…

Weaver, Tyler

394

First enantioselective total synthesis of (-)-tejedine.  

PubMed

[structure: see text] The first enantioselective total synthesis of (-)-tejedine (1) is reported. Tejedine is a seco-bisbenzyltetrahydroisoquinoline isolated in 1998 as a minor component from Berberis vulgaris. The synthesis was achieved using a strategy employing four key steps, including a chiral auxiliary-assisted diastereoselective Bischler-Napieralski cyclization. PMID:12153207

Wang, You-Chu; Georghiou, Paris E

2002-08-01

395

New Multiscale Transforms, Minimum Total Variation Synthesis  

E-print Network

transforms known under the name of the ridgelet [6] and the curvelet transforms [9, 8]. These systems combine-noising.' Keywords. Ridgelets, curvelets, wavelets, pseudo-polar FFT, Slant Stack, Radon transform, trigonometricNew Multiscale Transforms, Minimum Total Variation Synthesis: Applications to Edge-Preserving Image

Candes, Emmanuel J.

396

Courses Credit Hours Total Credit Hours  

E-print Network

Courses Credit Hours Total Credit Hours Hrs Attempted Hrs Completed Semester GPA Overall GPA Date are requesting to register for more than 20 credit hours during the fall/spring and more than 14 credit hours and approval from the Assistant/Associate Dean. For requests to register for more than 21 credit hours during

Mohaghegh, Shahab

397

Total productive maintenance; TPM that works  

Microsoft Academic Search

Tennessee Eastman Company (TEC) has defined TPM (total productive maintenance) as a partnership between the maintenance and production organizations to improve product quality, reduce waste, reduce manufacturing cost, increase equipment availability, and improve TEC's state of maintenance. This partnership emphasizes the involvement of all employees in maintaining facilities and equipment. TPM at TEC is composed of six concepts: utilization of

B. N. Maggard; C. L. Bailey; D. Moss

1989-01-01

398

Total productive maintenance: literature review and directions  

Microsoft Academic Search

Purpose – The purpose of this paper is to review the literature on Total Productive Maintenance (TPM) and to present an overview of TPM implementation practices adopted by the manufacturing organizations. It also seeks to highlight appropriate enablers and success factors for eliminating barriers in successful TPM implementation. Design\\/methodology\\/approach – The paper systematically categorizes the published literature and then analyzes

I. P. S. Ahuja; J. S. Khamba

2008-01-01

399

Relationship between total productive maintenance and performance  

Microsoft Academic Search

Increased global competition has augmented the importance of total productive maintenance (TPM) in obtaining and maintaining a competitive advantage. More and more organizations are seeking proactive tools such as TPM to enhance their competitive position. The paper focuses on gaining insights into the impact of TPM on the performance of the organization. There is support for a positive correlation between

S. A. Brah; W.-K. Chong

2004-01-01

400

Total pancreatic lipomatosis with malabsorption syndrome  

PubMed Central

Total fat replacement of the pancreas is rare. Focal fatty replacement is the most common degenerative lesion of pancreas. Focal fatty deposits have no major clinical significance; however, extreme fat replacement is of pathologic significance, as it is associated with marked reduction in exocrine function of pancreas, resulting in malabsorption due to pancreatic enzyme insufficiency. PMID:21584169

Anand, Rama; Narula, Mahender K.; Chaudhary, Vikas; Agrawal, Rohini

2011-01-01

401

The total synthesis of (-)-cryptocaryol A.  

PubMed

A stereoselective total synthesis of (-)-cryptocaryol A () is described. Key features of the 17-step route include the use of three boron-mediated aldol reaction-reduction sequences to control all stereocenters and an Ando modification of the Horner-Wadsworth-Emmons olefination that permitted the installation of the Z double bond of the ?-pyrone ring. PMID:25695350

Dias, L C; Kuroishi, P K; de Lucca, E C

2015-03-11

402

Enantioselective total synthesis of the lignan (+)-linoxepin.  

PubMed

An enantioselective total synthesis of the natural (+)-linoxepin (1) was accomplished in eleven steps from bromovanin (24). Key steps are a domino carbopalladation/ Mizoroki-Heck reaction with the formation of a pentacyclic system, an asymmetric hydroboration as well as an oxidative lactonization. PMID:25345835

Tietze, Lutz F; Clerc, Jérôme; Biller, Simon; Duefert, Svenia-C; Bischoff, Matthias

2014-12-15

403

Food safety and total quality management  

Microsoft Academic Search

Food safety is a growing global concern not only because of its continuing importance for public health but also because of its impact on international trade. The application of total quality management (TQM) provides the best possible care by continuously improving products and services to meet or possibly exceed the needs and expectations of the customer. Designing a TQM system

A. W. Barendsz

1998-01-01

404

Solar collector using total internal reflectance  

Microsoft Academic Search

A solar collector is constructed of a photoelectric cell mounted within a collector of the total internal reflectance type. The photoelectric cell has the form of a rod of a monocrystalline element or compound with a generally cylindrical junction spaced at a distance radially inwardly from the outer surface of the rod. The photoelectric cell is mounted within a trough

G. R. Johnson; M. G. Miles; I. O. Salyer; E. E. Hardy

1979-01-01

405

Learning Language through Total Physical Response.  

ERIC Educational Resources Information Center

The Total Physical Response (TPR) method of language instruction is introduced, and guidelines for designing and implementing TPR lessons for students with hearing impairments are provided. In TPR instruction, students develop understanding before speech or signing, understanding is demonstrated through actions, and new vocabulary is developed…

Marlatt, Edward A.

1995-01-01

406

Laconic discourses and total eclipses: abduction  

E-print Network

1 Laconic discourses and total eclipses: abduction in DICE JON OBERLANDER AND ALEX LASCARIDES 1 the same course of events. (1) Max entered the office. Then, John greeted him with a smile. After that, he showed Max to the seat in front of his desk. He then offered Max a cup of coffee. (2) Max entered

Lascarides, Alex

407

Relationship between electron-scattering grand total and ionization total cross sections  

Microsoft Academic Search

Regression formula which relates grand total cross section and ionization total cross section for electron scattering from simple hydrocarbons and from perfluorinated molecules has been proposed. This formula was then used to evaluate the ionization total cross sections for WF6 and for structured isomers of C3H4 and C4H6, at intermediate electron-impact energies. For WF6 the estimated ionization cross section is

Stanislaw Kwitnewski; El?bieta Ptasi?ska-Denga; Czeslaw Szmytkowski

2003-01-01

408

Relationship of plasma total protein and albumin to total calcium in peregrine falcons (Falco peregrinus)  

Microsoft Academic Search

A significant correlation was found between total calcium and total protein concentration in 124 plasma samples of captive peregrine falcons (r = 0.65; P<0.01). About 42% of the variability in calcium was attributable to the change in the plasma total protein concentration (R = 0.417). The correlation between calcium and albumin was significant (r = 0.33; P<0.01), but significantly smaller

J. T. Lumeij; J. D. Remple; K. E. Riddle

1993-01-01

409

Early Predictors of Hypocalcemia After Total Thyroidectomy  

PubMed Central

IMPORTANCE Postoperative hypocalcemia is common after total thyroidectomy, and perioperative monitoring of serum calcium levels is arguably the primary reason for overnight hospitalization. Confidently predicting which patients will not develop significant hypocalcemia may allow for a safe earlier discharge. OBJECTIVE To examine associations of patient characteristics with hypocalcemia, duration of hospitalization, and postoperative intact parathyroid hormone (IPTH) level after total thyroidectomy. DESIGN, SETTING, AND PARTICIPANTS Retrospective study of consecutive patients who underwent total thyroidectomy by a single high-volume surgeon between February 1, 2010, and November 30, 2012. Postoperative serum 25-hydroxyvitamin D (vitamin D), calcium, and IPTH levels were tested within 6 to 8 hours after surgery. Mild hypocalcemia was defined as any postoperative serum calcium level of less than 8.4 to 8.0 mg/dL. Significant hypocalcemia was defined as any postoperative serum calcium level of less than 8.0 mg/dL or the development of hypocalcemia-related symptoms. INTERVENTIONS Total thyroidectomy. MAIN OUTCOMES AND MEASURES Associations of patient demographic and clinical characteristics and laboratory values with postoperative mild and significant hypocalcemia were examined using univariate analysis, and independent predictors of hypocalcemia, duration of hospitalization, and IPTH level were determined using multivariate analysis. RESULTS Overall, 304 total thyroidectomies were performed. Mild and significant hypocalcemia occurred in 68 (22.4%) and 91 (29.9%) patients, respectively, of which the majority were female (P = .003). The development of significant hypocalcemia was associated with postoperative IPTH level (P < .001). On multivariate analysis, males had a decreased risk of developing mild (odds ratio, 0.37 [95% CI, 0.16–0.85]) and significant (odds ratio, 0.57 [95% CI, 0.09–0.78]) hypocalcemia. Every 10-pg/mL increase in postoperative IPTH level predicted a 43% decreased risk of significant hypocalcemia (P < .001) and an 18% decreased risk of hospitalization beyond 24 hours (P = .03). Presence of malignant neoplasm carried a 27% risk of mild hypocalcemia (P = .02). There was a progressively increasing risk of lower IPTH levels for each parathyroid gland inadvertently resected or autotransplanted. Male sex and African American race were independently predictive of higher IPTH levels. CONCLUSIONS AND RELEVANCE Low postoperative IPTH level, female sex, and presence of malignant neoplasm are all significant, independent predictors of hypocalcemia after total thyroidectomy. Clinicians should consider these variables when deciding how to best manage or prevent postoperative hypocalcemia. PMID:25321339

Noureldine, Salem I.; Genther, Dane J.; Lopez, Michael; Agrawal, Nishant; Tufano, Ralph P.

2015-01-01

410

Venous thromboembolic disease management patterns in total hip arthroplasty and total knee arthroplasty patients  

Microsoft Academic Search

The American Association of Hip and Knee Surgeons (AAHKS) distributed a survey to its members exploring practice patterns implemented to prevent venous thromboembolic disease (VTED) in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). Of 720 (33%) members, 236 responded. Prophylaxis was prescribed for 100% of patients during the course of hospitalization for THA and TKA. Warfarin

J. Wesley Mesko; Richard A Brand; Richard Iorio; Ivan Gradisar; Richard Heekin; Ross Leighton; Robert Thornberry

2001-01-01

411

Observation of the total solar eclipsis. L'observation des eclipses totales solaires  

SciTech Connect

A brief historical account of the solar-total-eclipses events is presented to show their importance, including their use for the scientific analysis of the solar corona, since 1848. The main parameters and a schema of the eclipses are given. Several examples of investigations performed during a solar total eclipse are discussed.

Koutchmy, S.

1987-03-01

412

| Los Alamos National Laboratory | Total Scattering Developments forTotal Scattering Developments for  

E-print Network

| Los Alamos National Laboratory | Total Scattering Developments forTotal Scattering DevelopmentsOperated by Los Alamos National Security, LLC for the U.S. Department of Energy's NNSA UNCLASSIFIED Operated by Los Alamos National Security, LLC for the U.S. Department of Energy's NNSA #12;| Los Alamos

Magee, Joseph W.

413

Fluorogenic membrane overlays to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and seawater  

Technology Transfer Automated Retrieval System (TEKTRAN)

Three assays were developed to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and other foods and in seawater and other environmental samples. Assays involve membrane overlays of overnight colonies on non-selective agar plates to detect ß-glucuronidase and lysyl am...

414

Increasing productivity through Total Reuse Management (TRM)  

NASA Technical Reports Server (NTRS)

Total Reuse Management (TRM) is a new concept currently being promoted by the NASA Langley Software Engineering and Ada Lab (SEAL). It uses concepts similar to those promoted in Total Quality Management (TQM). Both technical and management personnel are continually encouraged to think in terms of reuse. Reuse is not something that is aimed for after a product is completed, but rather it is built into the product from inception through development. Lowering software development costs, reducing risk, and increasing code reliability are the more prominent goals of TRM. Procedures and methods used to adopt and apply TRM are described. Reuse is frequently thought of as only being applicable to code. However, reuse can apply to all products and all phases of the software life cycle. These products include management and quality assurance plans, designs, and testing procedures. Specific examples of successfully reused products are given and future goals are discussed.

Schuler, M. P.

1991-01-01

415

Total knee arthroplasty in patients with poliomyelitis.  

PubMed

Between 1991 and 2001, 17 primary total knee arthroplasties were performed in 15 patients with limbs affected by poliomyelitis. Eight patients had a constrained condylar knee design, 8 a posterior stabilized design, and 1 a hinged design. Mean follow-up was 41.5 months. The mean Knee Society knee score improved from 45 preoperatively to 87 postoperative. Knee stability was obtained in all patients, including 4 patients with less than antigravity quadriceps strength. Radiologic evaluation showed satisfactory alignment with no signs of loosening. Complications included 1 case of deep venous thrombosis and 2 knees that required a manipulation for stiffness. Pain relief, functional improvement, and knee stability can be achieved after constrained total knee arthroplasty in patients with poliomyelitis despite impaired quadriceps strength, and osseous and soft tissue abnormalities. PMID:17562411

Jordan, Louis; Kligman, Mordechai; Sculco, Thomas P

2007-06-01

416

Total quality management: achieving service excellence.  

PubMed

Total Quality Management (TQM) provides a philosophy and a method for organizational renewal and redesign. It is based on the principle that productive work is accomplished through processes. Improving these processes requires the office team to objectively measure performance, discover root causes of problems, take corrective action, determine the effect of these actions, and secure achievements. TQM is a technique that provides a series of steps and set of tools. Through staff involvement and a desire for quality improvement, organizations involved in total quality note the accompanying satisfaction in taking constructive action, improving patient relations, and achieving service excellence. In today's competitive delivery environment, implementation of TQM can result in more satisfied patients, higher staff morale, and a more effective office team. PMID:9161134

Adelson, R

1997-01-01

417

Feminist leadership through total quality management.  

PubMed

Feminist leadership in nursing can be achieved through Total Quality Management. Total Quality Management (TQM) is a philosophy and technology that represents the foundation of a continuously improving organization. The feminist leadership ideas practiced by nurses, such as empowering staff and decision by consensus, are also central to TQM. Feminist leadership utilizing TQM enables employees to creatively contribute to the system without fear or intimidation. Employees at all levels in the organization are then empowered. The role of the feminist leader using TQM is one of facilitator rather than authority figure. Feminist leadership in nursing can spearhead the opportunity for improvement to provide high-quality, cost-effective health care in a troubled and complex economic environment. PMID:9119786

Lanza, M L

1997-01-01

418

Frustrated total internal reflection acoustic field sensor  

DOEpatents

A frustrated total internal reflection acoustic field sensor which allows the acquisition of the acoustic field over an entire plane, all at once. The sensor finds use in acoustic holography and acoustic diffraction tomography. For example, the sensor may be produced by a transparent plate with transparent support members tall enough to support one or more flexible membranes at an appropriate height for frustrated total internal reflection to occur. An acoustic wave causes the membrane to deflect away from its quiescent position and thus changes the amount of light that tunnels through the gap formed by the support members and into the membrane, and so changes the amount of light reflected by the membrane. The sensor(s) is illuminated by a uniform tight field, and the reflection from the sensor yields acoustic wave amplitude and phase information which can be picked up electronically or otherwise.

Kallman, Jeffrey S. (Pleasanton, CA)

2000-01-01

419

A Modern Approach to Total Wellbeing  

NASA Astrophysics Data System (ADS)

The events of the last decades have impacted our lives and our health significantly. We expected that the technology boom will improve our lives. While this may be true in a specific context, generally speaking our societies are suffering from moral decays, terrorism fears, wars, financial crisis and unpredictable acts of nature that are increasing in frequency and in intensity. The complex nature of the world we live is impacting our health and wellbeing considerably. Our health is not only determined by our physical health but is the end product of the interplay of the physical, mental, emotional, financial, relational and spiritual events of a lifetime. In this paper we develop a framework that will help us define and measure total wellbeing of individuals in our volatile societies. This framework will help us better understand the complex nature of total wellbeing and develop effective prevention and intervention strategies.

Hadzic, Maja; Chen, Meifania; Brouwer, Rick; Dillon, Tharam

420

The first total laparoscopic pancreatoduodenectomy in Poland  

PubMed Central

We present a case of a 55-year-old female patient with pancreatic head cancer who was treated with total laparoscopic pylorus-preserving pancreatoduodenectomy (TLPD) on 13.12.2013. The procedure as well as the postoperative course was uncomplicated. The patient was mobilized on the day of surgery; a liquid diet was introduced on day 1 and a full hospital diet on day 2 postoperatively. Drains were removed on the 3rd day after the procedure. Length of hospital stay was 6 days. The final pathology report confirmed the diagnosis of cancer. According to our knowledge this is the first report on total laparoscopic pancreatoduodenectomy in Poland performed by an entirely Polish team of surgeons. In our opinion, TLPD is feasible and similarly to other laparoscopic operations may improve postoperative recovery. PMID:25337173

Budzy?ski, Andrzej; Zub-Pokrowiecka, Anna; Zychowicz, Anna; Wierdak, Mateusz; Mat?ok, Maciej; Zaj?c, Ma?gorzata

2014-01-01

421

Metallosis in a total knee arthroplasty.  

PubMed

A 70-year-old woman presented with right knee pain and a 'grinding' sensation 6 months after a total knee replacement for osteoarthritis. Clinical examination revealed a valgus deformity, patellofemoral crepitus and a reduced knee flexion. Radiographs revealed distinctive findings including the 'bubble sign', 'cloud sign' and the 'metal line sign', which are diagnostic of metallosis. Metallosis is an uncommon complication of total joint replacements, where bone and periprosthetic soft tissues are infiltrated by metallic debris from wearing of the prostheses. This usually occurs in high-wear joints such as hips and knees. Treatment for patients diagnosed with metallosis is synovectomy and a revision surgery. Our patient underwent revision surgery 5 years after her initial surgery. PMID:24642179

Vivegananthan, Bhairavi; Shah, Rohi; Karuppiah, A S; Karuppiah, S V

2014-01-01

422

Gravitation experiments during the total solar eclipse  

SciTech Connect

The variations of the apparent vertical direction of the gravity field were measured with horizontal gravimeters acting as tilt meters during the total solar eclipse in Turkey in March 29, 2006. Three separated locations within the path of totality were chosen for observations, two spaced apart along the center line, and one off the center line. No anomaly was observed at the furthest location from the center line. Aperiodic oscillations in tilt were recorded at the two locations on the center line. These may be related to the eclipse phenomenon. The average tilt amplitude deviation during the eclipse over all locations and in all directions was 150 nrad, which can be regarded as a mean upper limit for the eclipse related changes in the tilt.

Kuusela, T.; Jaeykkae, J.; Kiukas, J.; Multamaeki, T.; Ropo, M.; Vilja, I. [Department of Physics, University of Turku, 20014 Turku (Finland)

2006-12-15

423

Total aplasia of the paranasal sinuses  

PubMed Central

Although a variety of theories have been proposed about functions of the paranasal sinuses, not one is clear today. Nonetheless, paranasal sinus–related diseases are associated with a high rate of morbidities. Therefore, it is essential to identify the structure and pathophysiology of the paranasal sinuses. Computed tomography (CT) is a valuable tool displaying anatomic variations and diseases. Because paranasal sinus development is a complex and long-lasting process, there are great structural variations between individuals. Several degrees and combinations of aplasias and hypoplasias have been reported; however, there is only one case of total paranasal sinus aplasia in the literature. Here, we present the second case of total paranasal sinus aplasia. Paranasal sinus development, functions of the paranasal sinuses, and the role of CT were evaluated. PMID:24124636

Korkmaz, Mukadder

2013-01-01

424

The glenoid in total shoulder arthroplasty  

Microsoft Academic Search

Management of glenohumeral arthrosis with a total shoulder prosthesis is becoming increasingly common. However, failure of\\u000a the glenoid component remains one of the most common causes for failure. Our understanding of this problem has evolved greatly\\u000a since the first implants were placed in the 1970’s. However glenoid failure remains a challenging problem to address and manage.\\u000a This article reviews the

Mark Schrumpf; Travis Maak; Sommer Hammoud; Edward V. Craig

425

NASA total quality management 1990 accomplishments report  

NASA Technical Reports Server (NTRS)

NASA's efforts in Total Quality Management are based on continuous improvement and serve as a foundation for NASA's present and future endeavors. Given here are numerous examples of quality strategies that have proven effective and efficient in a time when cost reduction is critical. These accomplishment benefit our Agency and help to achieve our primary goal, keeping American in the forefront of the aerospace industry.

1991-01-01

426

Total Variation Distance for Poisson Subset Numbers  

Microsoft Academic Search

Let n be an integer and A0,..., Ak random subsets of {1,..., n} of fixed sizes a0,..., ak, respectively chosen independently and uniformly. We provide an explicit and easily computable total variation bound between\\u000a the distance from the random variable \\u000a $$ W = {\\\\left| { \\\\cap ^{k}_{{j = 0}} A_{j} } \\\\right|} $$\\u000a , the size of the intersection of

Larry Goldstein; Gesine Reinert

2006-01-01

427

Total exchangeable potassium in response to amiloride.  

PubMed Central

The use of amiloride is described in twenty-four hypertensive patients who became hypokalaemic as a result of thiazide diuretic therapy in spite of oral potassium supplments. Amiloride caused a significant rise in exchangeable potassium, exchangeable potassium/kg body weight, and plasma potassium, together with a significant fall in plasma total carbon dioxide, body weight, systolic and diastolic blood pressures. These results suggest that amiloride has a useful role in this type of patient. PMID:733684

Pearce, V. R.; Antcliff, A. C.; Beevers, D. G.; Hamilton, M.

1978-01-01

428

Total exchangeable potassium in response to amiloride.  

PubMed

The use of amiloride is described in twenty-four hypertensive patients who became hypokalaemic as a result of thiazide diuretic therapy in spite of oral potassium supplments. Amiloride caused a significant rise in exchangeable potassium, exchangeable potassium/kg body weight, and plasma potassium, together with a significant fall in plasma total carbon dioxide, body weight, systolic and diastolic blood pressures. These results suggest that amiloride has a useful role in this type of patient. PMID:733684

Pearce, V R; Antcliff, A C; Beevers, D G; Hamilton, M

1978-08-01

429

An efficient total synthesis of (-)-huperzine A.  

PubMed

The total synthesis of Lycopodium alkaloid (-)-huperzine A has been accomplished in 10 steps with 17% overall yield from commercially abundant (R)-pulegone. The synthetic route features an efficient synthesis of 4 via a Buchwald-Hartwig coupling reaction, a dianion-mediated highly stereoselective alkylation of 4, and a rare example of an intramolecular Heck reaction of an enamine-type substrate. The stereoselective ?-elimination and the accompanying Wagner-Meerwein rearrangement are of particular interest. PMID:22900755

Ding, Rui; Sun, Bing-Feng; Lin, Guo-Qiang

2012-09-01

430

NASA total quality management 1989 accomplishments report  

NASA Technical Reports Server (NTRS)

Described here are the accomplishments of NASA as a result of the use of Total Quality Management (TQM). The principles in practice which led to these process refinements are important cultural elements to any organization's productivity and quality efforts. The categories of TQM discussed here are top management leadership and support, strategic planning, focus on the customer, employee training and recognition, employee empowerment and teamwork, measurement and analysis, and quality assurance.

1990-01-01

431

A GENUINELY HIGH ORDER TOTAL VARIATION DIMINISHING ...  

E-print Network

averages uj, the total variation of the numerical solution is measured by. (1.2) .... the zeros of polynomials to save cost, then we can only have the polynomial degree k of p(x) up to five, hence ...... The entrance is blocked for 10 min, after ... a magnified graph for the boxed region shown in Figure 5.4(d), where the solid line

432

Photon-Nucleus Total Cross Sections  

Microsoft Academic Search

Quantitative predictions for the energy and A dependence of the cross sections for nuclear photoabsorption and inelastic electron-nucleus scattering are given. In general, the nucleons do not contribute equally to the total photon-nucleus cross section when coherent contributions of photoproduced hadrons are taken into account. At low energies (Egamma~1 BeV), the cross sections are proportional to nuclear number A, but

Stanley J. Brodsky; Jon Pumplin

1969-01-01

433

Measurement of total organic concentration in water  

NASA Technical Reports Server (NTRS)

Instrument for determining total organic concentration in water uses no corrosive reagents or gases. Instead continuous ultraviolet photolysis process converts organic compounds to carbon dioxide (CO2). CO2 electrode is used to measure CO2 content. Only reagent necessary is oxygen, generated in situ by electrolyzing some water. In addition to application in aerospace industry, system has potential uses in pollution monitoring and in laboratory analyses.

Winkler, E.

1978-01-01

434

Thromboembolic complications after total hip replacement  

Microsoft Academic Search

We conducted a retrospective analysis of 1,640 consecutive patients undergoing total hip replacement between 1990 and 1997 under general anesthesia and receiving three different prophylactic regimens. The thromboembolic prophylaxis consisted of low-dose unfractioned heparin (UFH), low-molecular-weight heparin (LMWH), or indobufen (INDO). Postoperatively, occurrence of symptomatic deep vein thrombosis (DVT) or pulmonary embolism (PE) was recorded during the first 30 days

B. Borghi; A. Casati

2002-01-01

435

The benefits of total quality management.  

PubMed

In this article, we will review the implementation of the ISO 9000 quality system in the Department of Nuclear Medicine. We will also discuss the benefits of working with the ISO 9000 standards and explain why we have shifted our focus from ISO 9000 towards the EFQM model. After an introduction concerning Total Quality Management and the EFQM model, we will describe how we have used the EFQM model to date and how we intend to implement TQM in the future. PMID:11137800

Geraedts, H P; Montenarie, R; van Rijk, P P

2001-01-01

436

Postmaterialism influencing total entrepreneurial activity across nations  

Microsoft Academic Search

The relative stability of differences in entrepreneurial activity across countries suggests that other than economic factors\\u000a are at play. The objective of this paper is to explore how postmaterialism may explain these differences. A distinction is\\u000a made between nascent entrepreneurship, new business formation and a combination of the two, referred to as total entrepreneurial\\u000a activity, as defined within the Global

Lorraine Uhlaner; Roy Thurik

2007-01-01

437

Short, enantioselective total synthesis of chatancin.  

PubMed

An enantioselective total synthesis of the polycyclic diterpene (+)-chatancin, a potent PAF antagonist, is reported. Proceeding in seven steps from dihydrofarnesal, this synthetic route was designed to circumvent macrocyclization-based strategies to complex, cyclized cembranoids. The described synthesis requires only six chromatographic purifications, is high yielding, and avoids protecting-group manipulations. An X-ray crystal structure of this fragile marine natural product was obtained. PMID:25470723

Zhao, Yu-Ming; Maimone, Thomas J

2015-01-19

438

Solar Total Energy at Sandia Labs  

Microsoft Academic Search

The Sandia Laboratories' Solar Total Energy Program is described. This program consists of designing, building, installing, and operating a field of concentrating parabolic trough solar collectors which provide energy at 310 C, a 32-kW organic Rankine cycle power plant, and the heating and cooling equipment to utilize the cascaded, low-temperature energy from the turbine\\/generator. Included in the presentation are descriptions

J. A. Leonard

1976-01-01

439

Biocompatibility of materials for total joint replacement.  

PubMed

The clinical use of total joint prostheses demands absolute biocompatibility of the materials employed. The purpose of this experiment was the bioassay of some materials considered as possible candidates for use in total joint prostheses as load-bearing members or as wear-resistant surfaces. Some materials already in use were also tested. 316L stainless steel was used as a control. The materials were implanted as a standardized rod and in particulate form. An average of 12 samples per material were implanted in soft tissue for six months and a total of 145 rabbits were used in this study. Twenty-five materials including metals, polymers, and ceramics were tested in solid and powdered form. A semiquantitative evaluation of local tissue reaction and a study of organs was performed. Polymers and metallic materials showed in general a mild tissue reaction. Ceramics, which some authors describe as the best tolerated materials, elicited variable tissue responses. Some of these (glass-ceramics) presented very poor tissue tolerance. The least reactive, titanium oxide, titanium aluminate, and aluminum oxide, presented a degree of tissue reaction comparable to that of corrosion resistant metals, but not superior to them. Moderate reactivity was the general rule for particulate materials except for the Pyroceram glass-ceramics, polymides, and Teflon. Ultrahigh molecular weight polyethylene in particulate form elicited a rather cellular tissue response, a fact to be considered when projecting long-term results in total joint arthroplasty. No pathological changes compatible with systemic toxicity by materials tested were observed in the study of the organs. PMID:1254613

Escalas, F; Galante, J; Rostoker, W

1976-03-01

440

Total synthesis of (+)-antroquinonol and (+)-antroquinonol d.  

PubMed

The first total synthesis of (+)-antroquinonol and (+)-antroquinonol D, two structurally unique quinonols with a sesquiterpene side chain, is described. The route features an iridium-catalyzed olefin isomerization-Claisen rearrangement reaction (ICR), lactonization, and Grubbs olefin metathesis. The requisite ?,?-unsaturation was achieved via the selenylation/oxidation protocol and elimination of ?-methoxy group to provide two natural products from a common intermediate. PMID:25679542

Sulake, Rohidas S; Chen, Chinpiao

2015-03-01

441

Measured flexion following total knee arthroplasty.  

PubMed

Postoperative flexion is an important factor in the outcome of total knee arthroplasty. Although normal activities of daily living require a minimum of 105° to 110° of flexion, patients from non-Western cultures often engage in activities such as kneeling and squatting that require higher flexion. The desire to achieve greater flexion serves as the driving force for prosthetic modifications, including high-flexion designs. Techniques used to measure knee flexion and knee position during measurement are not often described or are different depending on the examiner. The purpose of this study was to compare active (self) and passive (assisted) flexion after successful total knee arthroplasty for 5 prostheses (2 standard and 3 high-flexion) using clinical (goniometer) and radiographic (true lateral radiograph) measurement techniques by different independent examiners.At a mean follow-up of 2.7 years (range, 1-5.6 years), a total of 108 patients (144 total knee arthroplasties) had completed the study. Mean postoperative active flexion was 111° clinically and 109° radiographically for the standard designs and 114° clinically and 117° radiographically for the high-flexion designs. Adding passive flexion increased flexion to 115° clinically and 117° radiographically for the standard designs and 119° clinically and 124° radiographically for the high-flexion designs. Flexion differences between the 2 measurement techniques (active vs passive and clinically vs radiographically) were statistically significant (P<.05). These findings demonstrate the importance of describing how flexion is measured in studies and understanding how the method of measurement can affect the findings. PMID:23027482

Mai, Kenny T; Verioti, Christopher A; Hardwick, Mary E; Ezzet, Kace A; Copp, Steven N; Colwell, Clifford W

2012-10-01

442

Trapezio-Metacarpal Arthroplasty by Total Prosthesis  

Microsoft Academic Search

Thirty-four total trapezio-matacarpal prostheses have been fitted since 1971. Twenty-eight have had a follow-up for more than six months (up to a maximum of five years) and allow a valid assessment of the situation.The operations were undertaken for rheumatoid, osteoarthritic disease, and following trauma. The reasons were either pain, mechanical instability, or stiffness. Two out of three times results were

J. Y. de la CAFFINIERE; P. AUCOUTURIER

1979-01-01

443

Total synthesis of cis-sylvaticin.  

PubMed

An asymmetric total synthesis of (+)-cis-sylvaticin is described. Key steps include the use of permanganate-mediated oxidative cyclization of 1,5-dienes to synthesize the two major fragments 2 and 3 and a catalytically efficient tethered RCM to unite these THF-containing fragments. In addition, t-BuP 4 base was found to reliably promote rapid alkylation of the butenolide precursor fragment 4. PMID:18489103

Brown, Lynda J; Spurr, Ian B; Kemp, Stephen C; Camp, Nicholas P; Gibson, Karl R; Brown, Richard C D

2008-06-19

444

Total Renewable Freshwater Supply By Country  

NSDL National Science Digital Library

Hosted by the Pacific Institute's The World's Water site, this page from the book The World's Water 1998-1999: The Biennial Report on Freshwater Resources, by Peter H. Gleick, features a table of Total Renewable Freshwater Supply By Country. For each country, the table lists annual renewable water resources in cubic kilometers per year, the year of the estimate, and the source of the estimate.

445

Total synthesis of enantiopure potassium aeshynomate.  

PubMed

Potassium aeshynomate (1) is the leaf-opening factor of the nyctinastic plant Aeshynomene indica L. In this article a convenient and efficient strategy for the total synthesis of enantiomerically pure 1 is described, starting from the l-arabinose derived chiron ent-6. The realized synthetic scheme involves a postcoupling oxidation approach and securely determines the absolute configuration of the targeted natural product, which remained unknown until now. PMID:24967505

Rizos, Stergios R; Stefanakis, John G; Kotoulas, Stefanos S; Koumbis, Alexandros E

2014-07-18

446

Plasma total-homocysteine in anorexia nervosa  

Microsoft Academic Search

Objective: The measurement of plasma total-homocysteine (tHcy) as a marker of folate and cobalamin status in patients with anorexia nervosa.Design: Plasma tHcy, folate, cobalamin and other determinats of tHcy of a random group of patients with anorexia nervosa were compared with our own reference values.Setting: The study was performed at the tertiary children's Hospital Sant Joan de Déu.Subjects: All the

D Moyano; MA Vilaseca; R Artuch; C Valls; N Lambruschini

1998-01-01

447

Total Hip Joint Replacement Biotelemetry System  

NASA Technical Reports Server (NTRS)

The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.

Boreham, J. F.; Postal, R. B.; Luntz, R. A.

1981-01-01

448

Total Synthesis of Hapalindoles J and U  

PubMed Central

The total synthesis of D,L-hapalindoles J and U has been accomplished. Hapalindole J was prepared in 11% overall yield over eleven synthetic steps and hapalindole U was prepared in 25% overall yield over thirteen synthetic steps from commercially available materials. The route employs a novel silyl ether-based strategy for accessing the 6:5:6:6 ring system of the hapalindoles rapidly and in good yields. PMID:22126131

Rafferty, Ryan J.; Williams, Robert M.

2011-01-01

449

Total synthesis of hapalindoles J and U.  

PubMed

The total synthesis of D,L-hapalindoles J and U has been accomplished. Hapalindole J was prepared in 11% overall yield over 11 synthetic steps and hapalindole U was prepared in 25% overall yield over 13 synthetic steps from commercially available materials. The route employs a novel silyl ether-based strategy for accessing the 6:5:6:6 ring system of the hapalindoles rapidly and in good yields. PMID:22126131

Rafferty, Ryan J; Williams, Robert M

2012-01-01

450

Science, specific knowledge, and total quality management  

Microsoft Academic Search

We analyze Total Quality Management (TQM) from an economic and organizational perspective. We find that TQM is a new organizing technology that is science-based, non-hierarchical, and non-market-oriented. It improves productivity by encouraging the use of science in decision-making and discouraging counter-productive defensive behavior. It also encourages effective creation and use of specific knowledge throughout the organization. Effective implementation of TQM

Karen Hopper Wruck; Michael C. Jensen

1994-01-01

451

Assessing Operational Total Lightning Visualization Products  

NASA Technical Reports Server (NTRS)

In May 2003, NASA's Short-term Prediction Research and Transition (SPoRT) program successfully provided total lightning data from the North Alabama Lightning Mapping Array (NALMA) to the National Weather Service (NWS) office in Huntsville, Alabama. The major accomplishment was providing the observations in real-time to the NWS in the native Advanced Weather Interactive Processing System (AWIPS) decision support system. Within days, the NALMA data were used to issue a tornado warning initiating seven years of ongoing support to the NWS' severe weather and situational awareness operations. With this success, SPoRT now provides real-time NALMA data to five forecast offices as well as working to transition data from total lightning networks at Kennedy Space Center and the White Sands Missile Range to the surrounding NWS offices. The only NALMA product that has been transitioned to SPoRT's partner NWS offices is the source density product, available at a 2 km resolution in 2 min intervals. However, discussions with users of total lightning data from other networks have shown that other products are available, ranging from spatial and temporal variations of the source density product to the creation of a flash extent density. SPoRT and the Huntsville, Alabama NWS are evaluating the utility of these variations as this has not been addressed since the initial transition in 2003. This preliminary analysis will focus on what products will best support the operational warning decision process. Data from 19 April 2009 are analyzed. On this day, severe thunderstorms formed ahead of an approaching cold front. Widespread severe weather was observed, primarily south of the Tennessee River with multiple, weak tornadoes, numerous severe hail reports, and wind. This preliminary analysis is the first step in evaluation which product(s) are best suited for operations. The ultimate goal is selecting a single product for use with all total lightning networks to streamline training and science sharing.

Stano, Geoffrey T.; Darden, Christopher B.; Nadler, David J.

2010-01-01

452

Radiobiological speculations on therapeutic total body irradiation  

Microsoft Academic Search

Unexpected total body irradiation (TBI) of human beings, involved in nuclear warfare or in accidents in nuclear reactors can be lethal. In the 1950s, bone marrow transplantation was discovered as a potentially life saving procedure after TBI in the dose range of 5.0 to 12.0 Gy. Since that time, deliberate or therapeutic TBI has been used to condition patients with

H. M. Vriesendorp

1990-01-01

453

Advanced lymphosarcoma treated by total body irradiation.  

PubMed Central

Twenty-five cases of clinical Stage III and Stage IV lymphosarcoma primarily treated by total body irradiation (TBI) are reported. Fifteen cases demonstrated nodular histology and 10 demonstrated diffuse histology by the Rappaport criteria. Treatments were 15 rad given twice weekly, calculated to midpelvis, to a total dose of 150 rad. Toxicity was confined to thrombocytopenia, one-third of patients requiring interruptions in the treatment course to allow platelet count recovery. Five patients had additional local irradiation. Complete responses were seen in 80% of patients and partial responses in 20%. Sixteen patients (64%) have been in continuous, unmaintained remission since treatments for variable periods to 39 months. Of 9 patients with clinically recurrent disease, 3 received further TBI and are in remission, 3 are in remission on chemotherapy, one patient has died, failing on all therapy, and 2 have not been treated. One patient died of pneumonia at 12 months, without clinical evidence of disease. Overall, actuarial survival is 87% at 2 years and compares well with survival in a sequential combination drug treated group of patients matched for age, sex, and histology, though differences are not statistically significant in these small groups. Total body irradiation is an effective systemic agent in the management of advanced lymphosarcoma and should be considered in treating this disease. PMID:810155

Chaffey, J. T.; Rosenthal, D. S.; Pinkus, F.; Hellman, S.

1975-01-01

454

Physical Activity After Total Joint Arthroplasty  

PubMed Central

Context: Total joint arthroplasty (TJA) is a common surgical option to treat painful degenerative joint disease. However, there is currently no consensus on the appropriate intensity of physical activity after TJA or how physical activity level affects the rate of revision surgery. Materials and Methods: A systematic review of the literature regarding physical or athletic activity after TJA was performed to determine current clinical opinion and recommendations regarding appropriate activity levels after TJA, as well as variables affecting successful surgery and improved outcomes. Results: Many studies in the literature regarding athletic activity after TJA focus on total hip arthroplasty and total knee arthroplasty. The literature reports contradictory results regarding rates of physical activity after TJA as well as the relationship between physical activity and rates of revision surgery. The current trend in expert opinion shows more liberal recommendations for patients to engage in athletic activity after TJA. Conclusions: Individual characteristics, lifestyle, and patient preferences must be taken into account when one considers appropriate recommendations for athletic activity after TJA. Current trends in clinical opinion favor a higher level of athletic activity after TJA, but clinicians should caution patients not to participate in contact sports or sports that create high joint loads in the replaced joint. PMID:23016041

Vogel, Laura A.; Carotenuto, Giuseppe; Basti, John J.; Levine, William N.

2011-01-01

455

Continuous passive motion after total knee arthroplasty.  

PubMed

We established a clinical retrospective study to determine the benefit of continuous passive motion after total knee replacement. Nineteen patients who had continuous passive motion (CPM) after total knee replacement were compared to a control group of 15 patients who did not have CPM. The number of days to discharge was 16 for the CPM group and 20 for the control group. When the patients with complications from CPM were excluded from the CPM group, the average number of days to discharge for the CPM group was 12. The average number of postoperative days before reaching 90 degrees of knee flexion was nine in the CPM group as compared to 16 days in the control group. The average blood loss was not significantly different in the two groups. There were four wound healing complications in the CPM group. All four complications occurred in patients who achieved 90 degrees of knee flexion in less than six days postoperatively. We developed a protocol for maximal use of CPM without significant wound complications after total knee surgery. PMID:3749998

Goletz, T H; Henry, J H

1986-09-01

456

Total chlorine content in the lower stratosphere  

SciTech Connect

A cryogenic whole air sampler and a filter sampler were used, simultaneously, on a balloon platform to capture and preserve all significant stratospheric chlorine species with the exception of Cl and ClO at altitudes of 15, 20, 25, and 30 km. The whole air samples were analyzed by gas chromatography to determine mixing ratios of CF/sub 2/Cl/sub 2/, CFCl/sub 3/, CH/sub 3/Cl, CH/sub 3/CCl/sub 3/, and CCl/sub 4/. Liquid extractions of the filter samples were analyzed for acidic and particulate chlorine content using-neutron activation and wet-chemistry techniques. Summation of the contributions from the major species produced total chlorine mixing ratios that decreased from 2.6 ppbv at 15 km to 2.2-2.5 ppbv for the higher altitudes. Omission of Cl and ClO introduced about a 3-7% error at 25-30 km and negligible error at 15 and 20 km. The combined contributions of all other omitted species introduced 1-2% error to the total chlorine values for all altitudes investigated. The increase in total acidic species content with increasing altitude correlates with the decrease in the mixing ratios of the chlorine species of tropospheric origin.

Gallagher, C.C.; Forsberg, C.A.; Mason, A.S.; Gandrud, B.W.

1985-10-20

457

Navigated versus conventional total knee arthroplasty.  

PubMed

Computer-aided navigation in total knee arthroplasty (TKA) promises improved alignment, performance, and survivorship. Previous meta-analyses demonstrated that navigation yields better component alignment; however, they did not discuss other indicators of performance. This meta-analysis compares navigated (NAV) and conventional (CONV) TKAs and includes clinical outcomes and adverse events. Forty-seven studies (22 randomized trials) of varying methodological quality involving 7,151 TKAs created the sample population. Statistical analyses included analysis of variance of weighted means and random effects modeling. As seen in previous meta-analyses, NAV is favored over CONV TKA. Analysis of surgical characteristics found that length of surgery and tourniquet times were lower for CONV, but not significant. Meta-analysis found that tourniquet times favored CONV but not a strong relationship for length of surgery. Analysis of individual adverse events did not reveal any significant differences. However, when examining adverse events in their totality, the NAV experienced significantly fewer complications. TKA performed with imageless navigation improves component alignment, provides for lower blood loss, improves clinical outcomes as measured by Knee Society and WOMAC scores, and has fewer total adverse events. Published data are insufficient to determine any correlations between component alignment and outcomes. PMID:24234551

Moskal, Joseph T; Capps, Susan G; Mann, John W; Scanelli, John A

2014-06-01

458

Climate Change and Tropical Total Lightning  

NASA Technical Reports Server (NTRS)

While global warming is regarded as a fact by many in the scientific community, its future impact remains a challenge to be determined and measured. The International Panel on Climate Change (IPCC) assessment report (IPCC, 2007) shows inconclusive answers on global rainfall trends and general agreement on a future drier climate with increased global warming. The relationship between temperature, humidity and convection is not linear and is strongly dependent on regional scale features, such as topography and land cover. Furthermore, the relationship between convective lightning production (thunderstorms) and temperature is even more complicated, being subjected to the cloud dynamics and microphysics. Total lightning (intracloud and cloud-to-ground) monitoring is a relatively new field of observation. Global and tropical total lightning began to be more extensively measured by satellites in the mid 90s. In this scope, the Lightning Imaging Sensor (LIS) onboard of the Tropical Rainfall Measurement Mission (TRMM) has been operational for over 11 years. Here we address total lightning trends observed by LIS from 1998 to 2008 in different temporal (annual and seasonal) and spatial (large and regional) scales. The observed 11-year trends are then associate to different predicted/hypothesized climate change scenarios.

Albrecht, R.; Petersen, W.; Buechler, D.; Goodman, S.; Blakeslee, R.; Christian, H.

2009-01-01

459

The 2012 Total Eclipse Expeditions in Queensland  

NASA Astrophysics Data System (ADS)

A total eclipse swept across Queensland and other sites in northeastern Australia on the early morning of 14 November 2012, local time. We mounted equipment to observe coronal images and spectra during the approximately 2 minutes of totality, the former for comparison with spacecraft images and to fill in the doughnut of imaging not well covered with space coronagraphs. Matching weather statistics, viewing was spotty, and our best observations were from a last-minute inland site on the Tablelands, with some observations from a helicopter at 9000 feet altitude over our original viewing site at Miallo. Only glimpses of the corona were visible at our Port Douglas and Trinity Beach, Cairns, locations, with totality obscured from our sites at Newell and Miallo, though some holes in the clouds provided coronal views from Palm Cove and elsewhere along the coast. Preliminary analysis of the spectra again shows Fe XIV stronger than Fe X, as in 2010 but not earlier, a sign of solar maximum, as was the coronal shape. An intriguing CME is discernible in the SE. Acknowledgments: We thank Terry Cuttle, Aram Friedman, Michael Kentrianakis, and Nicholas Weber for assistance and collaboration in Australia and Wendy Carlos for image processing. Our expedition was supported in part by NSF grant AGS-1047726 from Solar Terrestrial Research of the Atmospheric and Geospace Sciences Division, and by the Rob Spring Fund and Science Center funds at Williams College. ML was also supported in part by a Grant-In-Aid of Research from the National Academy of Sciences, administered by Sigma Xi, The Scientific Research Society (Grant ID: G20120315159311). VR and MS acknowledge support from projects VEGA 2/0003/13 and NGS-3139-12 of the National Geographic Society. We are grateful to K. Shiota (Japan) for kindly providing us with some of his 2012 eclipse coronal images.

Pasachoff, Jay M.; Babcock, B. A.; Lu, M.; Dantowitz, R.; Lucas, R.; Seiradakis, J. H.; Voulgaris, A.; Gaintatzis, P.; Steele, A.; Sterling, A. C.; Rusin, V.; Saniga, M.

2013-07-01

460

Total sleep deprivation on endogenous depression.  

PubMed

Ten endogenous depressive patients were deprived of sleep for two whole nights according to the following schedule: sleep/sleep deprivation/sleep/sleep deprivation/sleep. No drugs were administered. Experimental conditions were as neutral as possible. Blind and nonblind ratings were taken. The patients were generally rated as improved after sleep deprivation, but a substantial effect, though temporary with rapid relapse, occurred in only two cases. After subsequent sleep, relapse followed as a rule. The net antidepressive effect of the total procedure was slightly more than nil. PMID:1101846

van den Burg, W; van den Hoofdakker, R H

1975-09-01

461

Assuring the happy total knee replacement patient.  

PubMed

Total knee replacement (TKR) is one of the most common operations in orthopaedic surgery worldwide. Despite its scientific reputation as mainly successful, only 81% to 89% of patients are satisfied with the final result. Our understanding of this discordance between patient and surgeon satisfaction is limited. In our experience, focus on five major factors can improve patient satisfaction rates: correct patient selection, setting of appropriate expectations, avoiding preventable complications, knowledge of the finer points of the operation, and the use of both pre- and post-operative pathways. Awareness of the existence, as well as the identification of predictors of patient-surgeon discordance should potentially help with enhancing patient outcomes. PMID:24187368

Drexler, M; Dwyer, T; Chakravertty, R; Farno, A; Backstein, D

2013-11-01

462

Total synthesis of indole alkaloid alsmaphorazine D.  

PubMed

A concise total synthesis of rac-alsmaphorazine?D has been described for the first time. The efficient synthetic strategy features four key transformations: 1)?a catalytic intramolecular oxidative cyclization for the ?-lactamindole backbone; 2)?an oxidative cyclic aminal formation for the hexahydropyrrolo[2,3-b]pyrrole framework; 3)?a transannular radical cyclization for the construction of the diazabicyclo[3.3.1]nonane structure; and 4)?a one-pot desilylation/double epimerization reaction that affirms the relative stereochemistry. PMID:25418345

Zhu, Chenlong; Liu, Zhaobo; Chen, Guanyu; Zhang, Kai; Ding, Hanfeng

2015-01-12

463

Total Talar Extrusion without Soft Tissue Attachments  

PubMed Central

Total talar extrusion without a soft tissue attachment is an extremely rare injury and is rarely reported. Appropriate treatment remains controversial. We describe the long-term outcomes of two patients who had complete talar extrusion without remaining soft tissue attachment treated with arthrodesis. Both of our patients had complications such as infection and progressive osteolysis. We suggest reimplantation of the extruded talus after thorough debridement as soon as possible as a reasonable option unless the talus is contaminated or missing, because an open wound may arise from inside to outside. PMID:24900908

Lee, Ho Seong; Chung, Hyun Wook

2014-01-01

464

Soft tissue balancing in total shoulder replacement.  

PubMed

Total shoulder arthroplasty is now capable of recreating near anatomic reproduction of native bony shoulder anatomy, but the function and longevity of anatomic shoulder replacement is dependent on a competent soft tissue envelope and adequate motoring of all musculo-tendinous units about the shoulder. Balancing the soft tissues requires understanding of the anatomy and pathology, as well as technical skills. The advent of reverse shoulder biomechanics has brought with it special requirements of understanding of the soft tissue elements still left in the shoulder despite major rotator cuff deficiency. PMID:24390706

Mueller, Maike; Hoy, Gregory

2014-03-01

465

Applications of Satellite Total Lightning Observations  

NASA Technical Reports Server (NTRS)

Low-earth orbit satellite measurements of total lightning have diverse applications for lightning-related NOx production. Topics to be covered include: (1) current availability of gridded global and tropical lightning climatologies from the OTD and LIS sensors; (2) estimation of the IC:CG ratio from combination of satellite and surface network observations (relevant for net storm production); (3) determination of land and ocean storm flash rate spectra, and their implications for parameterized "scaling law" approaches to lightning NOx estimation; and (4) use of satellite observations to assess and correct for the range-dependent performance of groundbased systems, including LDAR and NLDN.

Boccippio, Dennis J.; Christian, High J.; Arnold, James E. (Technical Monitor)

2001-01-01

466

A completely implantable total artificial heart system.  

PubMed

The authors developed, built, and tested in vivo a completely implanted total artificial heart (TAH) system. The system used a reduced size version of a roller screw energy converter and mating sac blood pumps. The motor drive, pumps, and a compliance chamber were implanted intrathoracically. A canister containing controlling electronics and an emergency battery was implanted in the abdomen. The secondary coil of an inductive energy transmission and telemetry system was placed over the ribs. The system was implanted in three calves, that survived 0.5-13 days with the system. The system maintained safe left atrial pressures and adequate cardiac outputs during each animal's entire course. PMID:1751126

Snyder, A; Rosenberg, G; Weiss, W; Pierce, W; Pae, W; Marlotte, J; Nazarian, R; Ford, S

1991-01-01

467

MFR total ozone grid point data  

SciTech Connect

Multichannel filter radiometers (MFR) on four satellites of the Defense Meteorological Satellite Program (DMSP) measured infrared radiances in 16 channels including the 9.6 ..mu..m ozone band. The quality of these radiance data and their intercomparisons are discussed. A data base containing the calibrated radiance data and total ozone is archived on 108 magnetic tapes of 6250 bpi density at the National Space Science Data Center (NSSDC), Goddard Space Flight Center, Greenbelt, Maryland. These tapes were written in a packed binary form and are compatible only with a VAX 11/780 series computer.

Ellis, J.S.; Lovill, J.E.

1983-08-01

468

Total body nitrogen analysis. [neutron activation analysis  

NASA Technical Reports Server (NTRS)

Studies of two potential in vivo neutron activation methods for determining total and partial body nitrogen in animals and humans are described. A method using the CO-11 in the expired air as a measure of nitrogen content was found to be adequate for small animals such as rats, but inadequate for human measurements due to a slow excretion rate. Studies on the method of measuring the induced N-13 in the body show that with further development, this method should be adequate for measuring muscle mass changes occurring in animals or humans during space flight.

Palmer, H. E.

1975-01-01

469

Biomimetic total synthesis of santalin?y.  

PubMed

A biomimetic total synthesis of santalin?Y, a structurally complex but racemic natural product, is described. The key step is proposed to be a (3+2)?cycloaddition of a benzylstyrene to a "vinylogous oxidopyrylium", which is followed by an intramolecular Friedel-Crafts reaction. This cascade generates the unique oxafenestrane framework of the target molecule and sets its five stereocenters in one operation. Our work provides rapid access to santalin?Y and clarifies its biosynthetic relationship with other colorants isolated from red sandalwood. PMID:25858797

Strych, Sebastian; Journot, Guillaume; Pemberton, Ryan P; Wang, Selina C; Tantillo, Dean J; Trauner, Dirk

2015-04-20

470

Vaginal mass following uncemented total hip arthroplasty  

PubMed Central

A 53-year-old woman developed a vaginal mass following an uncemented total hip arthroplasty. The mass was in direct communication with the hip through an acetabular medial wall defect after loosening of the acetabular component. The mass formation was caused simultaneously by changes secondary to polyethylene wear, a tiny delamination of the porous titanium mesh coating and a broken antirotational tab on the acetabular cup, all of which may have served as sources of metal particles. A careful evaluation of the patient's history, symptoms, X-ray findings and computed tomography scans should always be performed to ensure accurate diagnosis. PMID:25404779

Shin, Young-Soo; Jung, Tae-Wan; Han, Seung-Beom

2014-01-01

471

Total skin electron irradiation techniques: a review  

PubMed Central

Total skin electron irradiation (TSEI) has been employed as one of the methods of mycosis fungoides treatment since the mid-twentieth century. In order to improve the effects and limit the complications following radiotherapy, a number of varieties of the TSEI method, frequently differing in the implementation mode have been developed. The paper provides a systematic review of the different varieties of TSEI. The discussed differences concerned especially: (i) technological requirements and geometric conditions, (ii) the alignment of the patient, (iii) the number of treatment fields, and (iv) dose fractionation scheme. PMID:24278046

Milecki, Piotr; Skórska, Ma?gorzata; Fundowicz, Dorota

2013-01-01

472

A convergent stereocontrolled total synthesis of (-)-terpestacin.  

PubMed

A stereocontrolled total synthesis of (-)-terpestacin has been achieved starting from (R)-(-)-carvone as a chiral pool and (E,E)-farnesol via a highly convergent approach. Thus, (R)-(-)-carvone was transformed into the cyclopentanone segment through a series of high yielding operations with the proper setup of all the stereochemical centers while (E,E)-farnesol was converted into the other requisite building block via a series of high yielding reactions. The cyclopentanone intermediate was both selectively enolized and alkylated at room temperature to yield the desired coupling product, which provided the natural product upon further transformations. PMID:22710980

Jin, Yehua; Qiu, Fayang G

2012-07-28

473

MEASUREMENT AND DECOMPOSITION OF TOTAL EXPOSURE USING THE TOTAL-ISOLATED-BY-MICROENVIRONMENT-EXPOSURE (TIME) MONITOR  

EPA Science Inventory

This paper describes a new, highly compact and lightweight monitor that directly measures personal exposure resolved into four microenvironments. he device is the "Total-Isolated-by-Microenvironment-Exposure (TIME)" monitor. he monitor can identify electronically a subject's micr...

474

Calculation of the total and total ionization cross sections for positron scattering on atomic hydrogen  

SciTech Connect

The total and total ionization cross sections for positron scattering on atomic hydrogen are calculated by applying the convergent-close-coupling method to the model where positronium-formation channels are omitted. This model accurately describes the physics of the scattering whenever the positronium formation cross section is negligible, in particular, above 100 eV for this system. The total ionization cross section results in this energy region are in excellent agreement with the recent measurements of Jones [ital et] [ital al]. [J. Phys. B 26, L483 (1993)], and so lie below the earlier measurements of Spicher [Phys. Rev. Lett. 64, 1019 (1990)], and the recent calculations of Acacia [ital et] [ital al]. [Phys. Rev. Lett. (to be published)]. The total cross section is in very good agreement with the recent measurements of Zhou [ital et] [ital al]. (unpublished) down to 30 eV.

Bray, I. (Electronic Structure of Materials Centre, The Flinders University of South Australia, G.P.O. Box 2100, Adelaide 5001 (Australia)); Stelbovics, A.T. (Centre for Atomic, Molecular and Surface Physics, School of Mathematical and Physical Sciences, Murdoch University, Perth 6150 (Australia))

1994-04-01

475

Simultaneous determination of total nitrogen and total phosphorus in freshwater samples using persulfate digestion  

Microsoft Academic Search

The accuracy and precision of total nitrogen (T?N) and total phosphorus (T?P) determinations in freshwater samples by the simultaneous digestion method using an oxidizing reagent solution of NaOH?K2S2O8 were assessed. Detection limits based on the blank test of nitrogen and phosphorus were 0.02 mgN\\/1 and 0.001 mgP\\/1, respectively. This simultaneous digestion method gave not only a high recovery and reproducibility

Masaaki Hosomi; Ryuichi Sudo

1986-01-01

476

Positron interactions with water–total elastic, total inelastic, and elastic differential cross section measurements  

SciTech Connect

Utilising a high-resolution, trap-based positron beam, we have measured both elastic and inelastic scattering of positrons from water vapour. The measurements comprise differential elastic, total elastic, and total inelastic (not including positronium formation) absolute cross sections. The energy range investigated is from 1 eV to 60 eV. Comparison with theory is made with both R-Matrix and distorted wave calculations, and with our own application of the Independent Atom Model for positron interactions.

Tattersall, Wade [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia) [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Chiari, Luca [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia)] [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia); Machacek, J. R.; Anderson, Emma; Sullivan, James P. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)] [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); White, Ron D. [Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia)] [Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Brunger, M. J. [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia) [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Buckman, Stephen J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia) [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Garcia, Gustavo [Instituto de F?sica Fundamental, Consejo Superior de Investigationes Cient?ficas (CSIC), Serrano 113-bis, E-28006 Madrid (Spain)] [Instituto de F?sica Fundamental, Consejo Superior de Investigationes Cient?ficas (CSIC), Serrano 113-bis, E-28006 Madrid (Spain); Blanco, Francisco [Departamento de F?sica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain)] [Departamento de F?sica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

2014-01-28

477

Previous gastric bypass surgery complicating total thyroidectomy.  

PubMed

Hypocalcemia is a well-known complication of total thyroidectomy. Patients who have previously undergone gastric bypass surgery may be at increased risk of hypocalcemia due to gastrointestinal malabsorption, secondary hyperparathyroidism, and an underlying vitamin D deficiency. We present the case of a 58-year-old woman who underwent a total thyroidectomy for the follicular variant of papillary thyroid carcinoma. Her history included Roux-en-Y gastric bypass surgery. Following the thyroid surgery, she developed postoperative hypocalcemia that required large doses of oral calcium carbonate (7.5 g/day), oral calcitriol (up to 4 ?g/day), intravenous calcium gluconate (2.0 g/day), calcium citrate (2.0 g/day), and ergocalciferol (50,000 IU/day). Her serum calcium levels remained normal on this regimen after hospital discharge despite persistent hypoparathyroidism. Bariatric surgery patients who undergo thyroid surgery require aggressive supplementation to maintain normal serum calcium levels. Preoperative supplementation with calcium and vitamin D is strongly recommended. PMID:25738720

Alfonso, Bianca; Jacobson, Adam S; Alon, Eran E; Via, Michael A

2015-03-01

478

Esophagojejunostomy after total gastrectomy for caustic injuries.  

PubMed

The objective of the study was to compare outcomes of emergency esophagogastrectomy (EGT) and total gastrectomy with immediate esophagojejunostomy (EJ) in patients with full-thickness caustic necrosis of the stomach and mild esophageal injuries. After caustic ingestion, optimal management of the esophageal remnant following removal of the necrotic stomach remains a matter of debate. Between 1987 and 2012, 26 patients (men 38%, median age 44 years) with isolated transmural gastric necrosis underwent EGT (n = 14) or EJ (n = 12). Early and long-term outcomes of both groups were compared. The groups were similar regarding age (P = 0.66), gender (0.24), and severity of esophageal involvement. Functional success was defined as nutritional autonomy after removal of the jejunostomy and tracheotomy tubes. Emergency morbidity (67% vs. 64%, P = 0.80), mortality (17% vs. 7%, P = 0.58), and reoperation rates (25% vs.14%, P = 0.63) were similar after EJ and EGT. One patient (8%) experienced EJ leakage. One patient in the EJ group and 13 patients in the EGT group underwent esophageal reconstruction (P < 0.0001). Aggregate in hospital length of stay was significantly longer in patients who underwent EGT (median 83 [33-201] vs. 36 [10-82] days, P = 0.001). Functional success after EJ and EGT was similar (90% vs.69%, P = 0.34). Immediate EJ can be safely performed after total gastrectomy for caustic injuries and reduces the need of further esophageal reconstruction. PMID:23621347

Chirica, M; Kraemer, A; Petrascu, E; Vuarnesson, H; Pariente, B; Halimi, B; Munoz-Bongrand, N; Sarfati, E; Cattan, P

2014-01-01

479

Spatial modelling of total storm rainfall  

NASA Technical Reports Server (NTRS)

The spatial structure of the depth of rainfall from a stationary storm event is investigated by using point process techniques. Cells are assumed to be stationary and to be distributed in space either independently according to a Poisson process, or with clustering according to a Neyman-Scott scheme. Total storm rainfall at the centre of each cell is a random variable and rainfall is distributed around the centre in a way specified by a spread function that may incorporate random parameters. The mean, variance and covariance structure of the precipitation depth at a point are obtained for different spread functions. For exponentially distributed centre depth and a spread function having quadratically exponential decay, the total storm depth at any point in the field is shown to have a gamma distribution. The probability of zero rainfall at a point is investigated, as is the stochastic variability of model parameters from storm to storm. Data from the Upper Rio Guaire basin in Venezuela are used in illustration.

Rodriguez-Iturbe, I.; Cox, D. R.; Eagleson, P. S.

1986-01-01

480

Totally thoracoscopic pulmonary anatomic segmentectomies: technical considerations  

PubMed Central

Background While video-assisted thoracic surgery (VATS) lobectomies are being increasingly accepted, VATS segmentectomies are still considered as technically challenging. With the renewed interest for sublobar resection in the management of early stage lung carcinomas, the thoracoscopic approach may have a major role in a near future. We report our technique and results. Patients and methods Totally thoracoscopic anatomic segmentectomiy, i.e., using only endoscopic instrumentation and video-display without utility incision, was attempted on 117 patients (51 males and 66 females), aged 18 to 81 years (mean: 62 years). The indication was a clinical N0 non-small cell lung carcinoma in 69 cases, a solitary metastasis in 17 cases and a benign lesion in 31 cases. The following segmentectomies were performed: right apicosuperior [26] right superior [10], right basilar [18], lingula sparing left upper lobectomy [15], left apicosuperior [11], lingula [7], left superior [14], left basilar [13] and subsegmental resection [3]. Segmentectomy was associated with a radical lymphadenectomy in 69 cases. Results There were 5 conversions to thoracotomy. The mean operative time was 181±52 minutes, the mean intraoperative blood loss was 77±81 cc. There were 12 postoperative complications (11.7%). The median postoperative stay was 5.5±2.2 days. Out of the 69 patients operated on for a cN0 lung carcinoma, 6 were finally upstaged. Conclusions Totally thoracoscopic anatomic pulmonary segmentectomies are feasible and have a low complication rate. PMID:24040524

Zaimi, Rym; Fournel, Ludovic; Grigoroiu, Madalina; Brian, Emmanuel; Neveu, Charles

2013-01-01

481

Total internal reflection modulator/deflector  

NASA Astrophysics Data System (ADS)

This document refers to a total internal reflection modulator/deflector assembly for use with a focused beam of polarized incident laser light. The application of a low direct current voltage (e.g., less than 50 volts) to a pair of identical stacked crystals exhibiting the Pockel's effect produces an index of refraction difference at their interface. Since the index changes are small, the incidence angle of the impinging polarized laser light is large, e.g., 89 degrees. In the preferred embodiment, one crystal is rotated relative to the other, such that the applied electric field causes and index changes of +(delta)n in one crystal and of -(delta)n in the other crystal. As a result, the impinging polarized laser light is refraction into two portions, one of which is totally internal reflected, and transmitted in the desired modulated conditions. Two electrode members are used to apply the low direct current voltage to the interface of the crystals, with the electrodes arranged to face each other across the crystals, and also positioned such that the incident light need not traverse them.

Birnbaum

1985-04-01

482

Annular and Total Solar Eclipses of 2010  

NASA Technical Reports Server (NTRS)

While most NASA eclipse bulletins cover a single eclipse, this publication presents predictions for two solar eclipses during 2010. This has required a different organization of the material into the following sections. Section 1 -- Eclipse Predictions: The section consists of a general discussion about the eclipse path maps, Besselian elements, shadow contacts, eclipse path tables, local circumstances tables, and the lunar limb profile. Section 2 -- Annular Solar Eclipse of 2010 Ja n 15: The section covers predictions and weather prospects for the annular eclipse. Section 3 -- Total Solar Eclipse of 2010 Jul 11: The se ction covers predictions and weather prospects for the total eclipse. Section 4 -- Observing Eclipses: The section provides information on eye safety, solar filters, eclipse photography, and making contact timings from the path limits. Section 5 -- Eclipse Resources: The final section contains a number of resources including information on the IAU Working Group on Eclipses, the Solar Eclipse Mailing List, the NASA eclipse bulletins on the Internet, Web sites for the two 2010 eclipses, and a summary identifying the algorithms, ephemerides, and paramete rs used in the eclipse predictions.

Espenak, Fred; Anderson, J.

2008-01-01

483

Methods development for total organic carbon accountability  

NASA Technical Reports Server (NTRS)

This report describes the efforts completed during the contract period beginning November 1, 1990 and ending April 30, 1991. Samples of product hygiene and potable water from WRT 3A were supplied by NASA/MSFC prior to contract award on July 24, 1990. Humidity condensate samples were supplied on August 3, 1990. During the course of this contract chemical analyses were performed on these samples to qualitatively determine specific components comprising, the measured organic carbon concentration. In addition, these samples and known standard solutions were used to identify and develop methodology useful to future comprehensive characterization of similar samples. Standard analyses including pH, conductivity, and total organic carbon (TOC) were conducted. Colorimetric and enzyme linked assays for total protein, bile acid, B-hydroxybutyric acid, methylene blue active substances (MBAS), urea nitrogen, ammonia, and glucose were also performed. Gas chromatographic procedures for non-volatile fatty acids and EPA priority pollutants were also performed. Liquid chromatography was used to screen for non-volatile, water soluble compounds not amenable to GC techniques. Methods development efforts were initiated to separate and quantitate certain chemical classes not classically analyzed in water and wastewater samples. These included carbohydrates, organic acids, and amino acids. Finally, efforts were initiated to identify useful concentration techniques to enhance detection limits and recovery of non-volatile, water soluble compounds.

Benson, Brian L.; Kilgore, Melvin V., Jr.

1991-01-01

484

Dual mobility cups in total hip arthroplasty  

PubMed Central

Total hip arthroplasty (THA) is considered one of the most successful surgical procedures in orthopaedics. With the increase in the number of THAs performed in the world in the next decades, reducing or preventing medical and mechanical complications such as post-operative THA instability will be of paramount importance, particularly in an emerging health care environment based on quality control and patient outcome. Dual mobility acetabular component (also known as unconstrained tripolar implant) was introduced in France at the end of the 1970s as an alternative to standard sockets, to reduce the risk of THA dislocation in patients undergoing primary THA in France. Dual mobility cups have recently gained wider attention in the United States as an alternative option in the prevention and treatment of instability in both primary and revision THA and offer the benefit of increased stability without compromising clinical outcomes and implant longevity. In this article, we review the use of dual mobility cup in total hip arthroplasty in terms of its history, biomechanics, outcomes and complications based on more than 20 years of medical literature. PMID:25035820

De Martino, Ivan; Triantafyllopoulos, Georgios Konstantinos; Sculco, Peter Keyes; Sculco, Thomas Peter

2014-01-01

485

Plasmoid Ejection at a Solar Total Eclipse  

NASA Astrophysics Data System (ADS)

The existence of coronal plasmoids has been postulated for many years in order to supply material to streamers and possibly to the solar wind (SW). The W-L SoHO C2 Lasco coronagraph observations were made under the 2.2 solar radii (R0) occulting disk to look at the ultimate sources of the SW; EUV imagers are preferably devoted to the analysis of the corona on and very near the solar disk. Here, in addition to eclipse white-light (W-L) snapshots, we used the new SWAP space-borne imager designed for the systematic survey of coronal activity in the EUV lines near 17.4 nm, over a field of view (FOV) up to 2 R0. Using summed and co-aligned images, the corona can then be evaluated for the 1st time up to the limit of this FOV. At the time of the July 11, 2010, solar total eclipse a 20h continuous run of observations was collected, including images taken during eclipse totality from several ground observing locations where W-L data were collected. A plasmoid-like off-limb event was followed using the SWAP summed

Koutchmy, S.; Bazin, C.; Berghmans, D.; De Groof, A.; Druckmüller, M.; Tavabi, E.; Engell, A.; Filippov, B.; Golub, L.; Lamy, Ph.; Linker, J.; Mikic, Z.; Mouette, J.; Nitschelm, Ch.; Seaton, D.; Slemzin, V.

2012-06-01

486

Extensor mechanism allograft in total knee arthroplasty  

PubMed Central

Objective To analyze the experience with allograft transplantation of the extensor mechanism in total knee arthroplasty and compare results with the international experience. Methods We retrospectively evaluated three cases of extensor mechanism allograft after total knee arthroplasty performed in our hospital with the aid of one of the few tissue banks in Brazil and attempt to establish whether our experiences were similar to others reported in the world literature regarding patient indication, techniques, and outcomes. Results Two cases went well with the adopted procedure, and one case showed bad results and progressed to amputation. As shown in the literature, the adequate tension of the graft, appropriate tibial fixation and especially the adequate patient selection are the better predictors of good outcomes. Previous chronic infection can be an unfavorable predictor. Conclusion This surgical procedure has precise indication, albeit uncommon, either because of the rarity of the problem or because of the low availability of allografts, due to the scarcity of tissue banks in Brazil. Level of Evidence IV, Case Series. PMID:24453688

Helito, Camilo Partezani; Gobbi, Riccardo Gomes; Tozi, Mateus Ramos; Félix, Alessandro Monterroso; Angelini, Fábio Janson; Pécora, José Ricardo

2013-01-01

487

Periprosthetic Fractures Following Total Knee Arthroplasty  

PubMed Central

Periprosthetic fractures after total knee arthroplasty may occur in any part of the femur, tibia and patella, and the most common pattern involves the supracondylar area of the distal femur. Supracondylar periprosthetic fractures frequently occur above a well-fixed prosthesis, and risk factors include anterior femoral cortical notching and use of the rotational constrained implant. Periprosthetic tibial fractures are frequently associated with loose components and malalignment or malposition of implants. Fractures of the patella are much less common and associated with rheumatoid arthritis, use of steroid, osteonecrosis and malalignment of implants. Most patients with periprosthetic fractures around the knee are the elderly with poor bone quality. There are many difficulties and increased risk of nonunion after treatment because reduction and internal fixation is interfered with by preexisting prosthesis and bone cement. Additionally, previous soft tissue injury is another disadvantageous condition for bone healing. Many authors reported good clinical outcomes after non-operative treatment of undisplaced or minimally displaced periprosthetic fractures; however, open reduction or revision arthroplasty was required in displaced fractures or fractures with unstable prosthesis. Periprosthetic fractures around the knee should be prevented by appropriate technique during total knee arthroplasty. Nevertheless, if a periprosthetic fracture occurs, an appropriate treatment method should be selected considering the stability of the prosthesis, displacement of fracture and bone quality.

Kim, Nam Ki

2015-01-01

488

Footprint mismatch in lumbar total disc arthroplasty  

PubMed Central

Lumbar disc arthroplasty has become a popular modality for the treatment of degenerative disc disease. The dimensions of the implants are based on early published geometrical measurements of vertebrae; the majority of these were cadaver studies. The fit of the prosthesis in the intervertebral space is of utmost importance. An undersized implant may lead to subsidence, loosening and biomechanical failure due to an incorrect center of rotation. The aim of the present study was to measure the dimensions of lumbar vertebrae based on CT scans and assess the accuracy of match in currently available lumbar disc prostheses. A total of 240 endplates of 120 vertebrae were included in the study. The sagittal and mediolateral diameter of the upper and lower endplates were measured using a digital measuring system. For the levels L4/L5 and L5/S1, an inappropriate size match was noted in 98.8% (Prodisc L) and 97.6% (Charite) with regard to the anteroposterior diameter. Mismatch in the anterior mediolateral diameter was noted in 79.3% (Prodisc L) and 51.2% (Charite) while mismatch in the posterior mediolateral diameter was observed in 91.5% (Prodisc L) and 78% (Charite) of the endplates. Surgeons and manufacturers should be aware of the size mismatch of currently available lumbar disc prostheses, which may endanger the safety and efficacy of the procedure. Larger footprints of currently available total disc arthroplasties are required. PMID:18791748

Michaela, Gstoettner; Denise, Heider; Liebensteiner, Michael

2008-01-01

489

Periprosthetic fractures following total knee arthroplasty.  

PubMed

Periprosthetic fractures after total knee arthroplasty may occur in any part of the femur, tibia and patella, and the most common pattern involves the supracondylar area of the distal femur. Supracondylar periprosthetic fractures frequently occur above a well-fixed prosthesis, and risk factors include anterior femoral cortical notching and use of the rotational constrained implant. Periprosthetic tibial fractures are frequently associated with loose components and malalignment or malposition of implants. Fractures of the patella are much less common and associated with rheumatoid arthritis, use of steroid, osteonecrosis and malalignment of implants. Most patients with periprosthetic fractures around the knee are the elderly with poor bone quality. There are many difficulties and increased risk of nonunion after treatment because reduction and internal fixation is interfered with by preexisting prosthesis and bone cement. Additionally, previous soft tissue injury is another disadvantageous condition for bone healing. Many authors reported good clinical outcomes after non-operative treatment of undisplaced or minimally displaced periprosthetic fractures; however, open reduction or revision arthroplasty was required in displaced fractures or fractures with unstable prosthesis. Periprosthetic fractures around the knee should be prevented by appropriate technique during total knee arthroplasty. Nevertheless, if a periprosthetic fracture occurs, an appropriate treatment method should be selected considering the stability of the prosthesis, displacement of fracture and bone quality. PMID:25750888

Yoo, Jae Doo; Kim, Nam Ki

2015-03-01