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1

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

2

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

3

Midterm results with Birmingham Hip Resurfacing/Synergy stem modular metal-on-metal total hip arthroplasty.  

PubMed

Large head modular metal-on-metal total hip replacement (MoMTHR) has been shown to have increased revision rates in the National joint registry and in literature. We reviewed 41 consecutive patients with 44 hips who had large head MoM THR using a Birmingham Hip Resurfacing (BHR) cup/Synergy stem combination between June 2005 and Nov 2009 with a mean followup of 59.5 months. In this series we had a revision rate of 6.8% (3/44) for adverse reaction to metal debris (ARMD), persistent groin pain and instability. Kaplan-Meier analysis showed a mean cumulative survival rate of 79.2% (95% CI: 75.5%-82.9%) In addition there is a subset of 5/44 patients (113%) with mild grade groin pain who may need revision in the future. Based on these findings, we do not recommend performance of large head MoMTHR in the future. PMID:24205767

Hosny, Hazem A H; Srinivasan, Sreebala C M; Keenan, Jonathan; Fekry, Helmy

2013-08-01

4

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

5

Large-diameter metal-on-metal total hip arthroplasties: a page in orthopedic history?  

PubMed

Large-diameter metal-on-metal (MoM) bearings evolved from the success of hip resurfacing. These implants were used in revision surgery in cases with well-fixed acetabular cups but loose or failed femoral stems, to avoid cup revision. Early data showed low rates of dislocation and potentially low wear profiles due to better fluid film lubrication. The risk of impingement was also thought to be low due to the increased head-neck ratio. Subsequently large-diameter MoM heads gained popularity in primary hip replacement. Recent data has emerged on the unacceptably high revision rates among patients with large-diameter MoM total hip arthroplasties (THAs), high blood levels of metal ions, and adverse tissue reactions. The head-neck (cone-taper) modular interface probably represents the weak link in large metal heads that have been used on conventional tapers. Increased torque of the large head, micromotion, and instability at the cone-taper interface, synergistic interactions between corrosion and wear, edge loading, low clearance, and psoas impingement are the likely causes for early failure of these prostheses. PMID:23529961

Singh, Gurpal; Meyer, Heiko; Ruetschi, Marcel; Chamaon, Kathrin; Feuerstein, Bernd; Lohmann, Christoph H

2013-11-01

6

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

7

Large versus small femoral heads in metal-on-metal total hip arthroplasty  

Microsoft Academic Search

The recent resurgence of metal-on-metal total hip arthroplasty has afforded the surgeon new options in femoral head diameters that were not previously available. Reduction in the risk for dislocation and potential improvements in articular wear are the obvious advantages of large-diameter femoral heads. Total hips with larger-diameter femoral heads are more resistant to dislocation. The clinical experience with 616 38

John M. Cuckler; K. David Moore; Adolph V. Lombardi; Edward McPherson; Roger Emerson

2004-01-01

8

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

9

Metal-on-metal vs metal-on-improved polyethylene bearings in total hip arthroplasty.  

PubMed

Major weaknesses of total hip arthroplasty (THA) in the 20th century were polyethylene wear and dislocation. Efforts to improve THA took several directions including improvement of polyethylene and use of metal-on-metal (MoM) articulations. Metal-on-metal articulations showed excellent early results, but concerns mount over hypersensitivity and increasing failure. This study compares our experience with MoM and metal-on-improved polyethylene (MoIP) bearings in primary THA. We identified 1362 patients undergoing 1589 MoM THA and 693 patients undergoing 779 MoIP THA (all compression molded and sterilized in argon). Overall, more MoM than MoIP cups have been revised (4.0% vs 2.2%; P = .0241). Revision incidence for infection was similar; higher with MoM for loosening (P = .0020), metal complication (P = .0017), and combined aseptic causes (P = .0067); and higher for dislocation in MoIP (P = .0246). Metal-on-improved polyethylene devices had superior results compared with MoM in this study. Furthermore, 5 MoIP revisions were liner exchanges, a conservative option not available with MoM. PMID:21723699

Molli, Ryan G; Lombardi, Adolph V; Berend, Keith R; Adams, Joanne B; Sneller, Michael A

2011-09-01

10

A comparative assessment of small-head metal-on-metal and ceramic-on-polyethylene total hip replacement.  

PubMed

Large-head metal-on-metal (MoM) total hip replacements (THR) have given rise to concern. Comparative studies of small-head MoM THRs over a longer follow-up period are lacking. Our objective was to compare the incidence of complications such as infection, dislocation, revision, adverse local tissue reactions, mortality and radiological and clinical outcomes in small-head (28 mm) MoM and ceramic-on-polyethylene (CoP) THRs up to 12 years post-operatively. A prospective cohort study included 3341 THRs in 2714 patients. The mean age was 69.1 years (range 24 to 98) and 1848 (55.3%) were performed in women, with a mean follow-up of 115 months (18 to 201). There were 883 MoM and 2458 CoP bearings. Crude incidence rates (cases/1000 person-years) were: infection 1.3 vs 0.8; dislocation 3.3 vs 3.1 and all-cause revision 4.3 vs 2.2, respectively. There was a significantly higher revision rate after ten years (adjusted hazard ratio 9.4; 95% CI 2.6 to 33.6) in the MoM group, and ten of 26 patients presented with an adverse local tissue reaction at revision. No differences in mortality, osteolysis or clinical outcome were seen. In conclusion, we found similar results for small-head MoM and CoP bearings up to ten years post-operatively, but after ten years MoM THRs had a higher risk of all-cause revision. Furthermore, the presence of an adverse response to metal debris seen in the small-head MOM group at revision is a cause for concern. PMID:24986938

Lübbeke, A; Gonzalez, A; Garavaglia, G; Roussos, C; Bonvin, A; Stern, R; Peter, R; Hoffmeyer, P

2014-07-01

11

Large diameter metal on metal total hip replacement for femoral neck fractures with neurological conditions  

PubMed Central

Background: Patients with Parkinson's disease and poliomyelitis can have a femoral neck fracture; yet, the optimal methods of treatment for these hips remains controversial. Many constrained or semi-constrained prostheses, using constrained liners (CLs) with a locking mechanism to capture the femoral head, were used to treat femoral neck fractures in patients with neurological disorders. We retrospectively studied a group of patients with Parkinson's disease and poliomyelitis who sustained femoral neck fractures and were treated by total hip arthroplasty using an L-MoM prosthesis. Materials and Methods: We retrospectively reviewed 12 hips in 12 patients who underwent large-diameter metal-on-metal (L-MoM) total hip replacement between May 2007 and October 2009. Eight of the 12 patients (8 hips; 66.7%) had Parkinson's disease and 4 patients (4 hips; 33.3%) were affected with poliomyelitis. Results: The followup time was 5.2 years (range 3.6-6.0 years). At the latest followup, all the patients showed satisfactory clinical and radiographic results, with pain relief. No complications, such as dislocation or aseptic loosening occurred. Conclusion: We believe the use of L-MoM can diminish the rate of instability or dislocation, after operation. The L-MoM is an option for patients with Parkinson's disease and poliomyelitis with femoral neck fracture. PMID:25404774

Li, Jia; Zheng, Wei; Zhao, Jinzhu; Liu, Denghui; Xu, Weidong

2014-01-01

12

Poor short term outcome with a metal-on-metal total hip arthroplasty.  

PubMed

Metal-on-metal (MoM) bearings for total hip arthroplasty (THA) have come under scrutiny with reports of high failure rates. Clinical outcome studies with several commercially available MoM THA bearings remain unreported. We evaluated 78 consecutive MoM THAs from a single manufacturer in 68 patients. Sixty-six received cobalt-chrome (CoCr) monoblock and 12 received modular titanium acetabular cups with internal CoCr liners. Femoral components were titanium with modular necks. At average 2.1 years postoperatively, 12 THAs (15.4%) demonstrated aseptic failure (10 revisions, 2 revision recommended). All revised hips demonstrated capsular necrosis with positive histology reaction for aseptic lymphocytic vasculitis-associated lesions/adverse local tissue reactions. Prosthetic instability following revision surgery was relatively common. Female gender was a strong risk factor for failure, though smaller cups were not. Both monoblock and modular components fared poorly. Corrosion was frequently observed around the proximal and distal end of the modular femoral necks. PMID:23538122

Levy, Yadin D; Ezzet, Kace A

2013-08-01

13

Acute delayed infection: increased risk in failed metal on metal total hip arthroplasty.  

PubMed

Adverse local tissue reactions occurring in metal-on-metal total hip arthroplasty (MoM THA) could potentially lead to secondary failure modes such as dislocation or infection. The authors report a series of 124 patients treated with MoM hip arthroplasty between 2006 and 2010 with a minimum follow-up of 3 years. Eight hips presented with acute delayed or late periprosthetic joint infection (PJI) (defined as an infection occurring after 3 months in an otherwise well functioning implant). The rate of infection observed was higher than expected, almost 4 times higher (5.6%) compared to previous historical cohorts from our institution (1.3%). This high risk of infection in patients with DePuy ASR implants requires further study but we theorize that the increased prevalence of infection could be due to a combination of particulate debris, molecular (rather than particulate) effects of Co and Cr ions on soft tissues, and/or products of corrosion that may change the local environment predisposing to infection. PMID:24851788

Prieto, Hernan A; Berbari, Elie F; Sierra, Rafael J

2014-09-01

14

High failure rate of the R3 metal-on-metal total hip arthroplasty.  

PubMed

We report our failures with the use of the R3 metal-on-metal bearing. Forty six patients had an R3 acetabular system metal-on-metal THR in our centre between March 2007 and March 2009. All operations were performed using femoral components and appropriately matched femoral heads manufactured by Smith and Nephew. Twelve patients underwent revision surgery for adverse reaction to metal debris (ARMD). The median acetabular inclination was 40 degrees (range 21.1-49.1) and the median acetabular anteversion was 7.5 degrees (range 3.3-10.4). The median serum Cobalt was 9.9 µg/L (range 3.1-45) and the median serum Chromium was 5.8 µg/L (range 1.8-19.3). The time to revision was 39.2 months (range 13-53). Our current failure rate is 24%. PMID:25096456

Dramis, Asterios; Clatworthy, Elizabeth; Jones, Stephen A; John, Alun

2014-01-01

15

Magnetic resonance imaging of painful metal-on-metal total hip replacement.  

PubMed

Consecutive patients that had primary metal-on-metal (MoM) or metal-on-polyethylene (MoP) hip arthroplasty were prospectively enrolled to this study. All operated hips were evaluated with MRI by one radiologist who was blinded to the radiographic findings and clinical symptoms. Three groups of patients were formed: (1) thirteen MoM THRs in 13 patients with groin pain (Group 1), (2) ten MoM THRs in 10 patients with no pain (Group 2), (3) five MoP THRs in 4 patients without pain (control group). Abnormal MRI findings were distributed in all groups in a balanced way, irrespective of the patients' symptoms, prostheses, or metal ion levels. Two patients from Group 1 and one patient of Group 3 (control group) were diagnosed with a large periprosthetic mass (pseudotumor). PMID:24906294

Nikolaou, Vassilios S; Petit, Alain; Khoury, Viviane; Blain-Pare, Etienne; Zukor, David J; Huk, Olga L; Antoniou, John

2015-02-01

16

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

17

Retrieval analysis of 240 metal-on-metal hip components, comparing modular total hip replacement with hip resurfacing.  

PubMed

This study compared component wear rates and pre-revision blood metal ions levels in two groups of failed metal-on-metal hip arthroplasties: hip resurfacing and modular total hip replacement (THR). There was no significant difference in the median rate of linear wear between the groups for both acetabular (p = 0.4633) and femoral (p = 0.0872) components. There was also no significant difference in the median linear wear rates when failed hip resurfacing and modular THR hips of the same type (ASR and Birmingham hip resurfacing (BHR)) were compared. Unlike other studies of well-functioning hips, there was no significant difference in pre-revision blood metal ion levels between hip resurfacing and modular THR. Edge loading was common in both groups, but more common in the resurfacing group (67%) than in the modular group (57%). However, this was not significant (p = 0.3479). We attribute this difference to retention of the neck in resurfacing of the hip, leading to impingement-type edge loading. This was supported by visual evidence of impingement on the femur. These findings show that failed metal-on-metal hip resurfacing and modular THRs have similar component wear rates and are both associated with raised pre-revision blood levels of metal ions. PMID:21357950

Matthies, A; Underwood, R; Cann, P; Ilo, K; Nawaz, Z; Skinner, J; Hart, A J

2011-03-01

18

Understanding the differences between the wear of metal-on-metal and ceramic-on-metal total hip replacements.  

PubMed

Hip simulator studies have been carried out extensively to understand and test artificial hip implants in vitro as an efficient alternative to obtaining long-term results in vivo. Recent studies have shown that a ceramic-on-metal material combination lowers the wear by up to 100 times in comparison with a typical metal-on-metal design. The reason for this reduction remains unclear and for this reason this study has undertaken simple tribometer tests to understand the fundamental material loss mechanisms in two material combinations: metal-on-metal and ceramic-on-ceramic. A simple-configuration reciprocating pin-on-plate wear study was performed under open-circuit potential (OCP) and with applied cathodic protection (CP) in a serum solution using two tribological couples: firstly, cobalt-chromium (Co-Cr) pins against Co-Cr plates; secondly, Co-Cr pins against alumina (Al2O3) plates. The pin and plate surfaces prior to and after testing were examined by profilometry and scanning electron microscopy. The results showed a marked reduction in wear when CP was applied, indicating that total material degradation under the OCP condition was attributed to corrosion processes. The substitution of the Co-Cr pin with an Al2O3 plate also resulted in a dramatic reduction in wear, probably due to the reduction in the corrosion-wear interactions between the tribological pair. PMID:18491698

Figueiredo-Pina, C G; Yan, Y; Neville, A; Fisher, J

2008-04-01

19

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

20

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

21

Total hip arthroplasty using large-diameter metal-on-metal articulation in patients with neuromuscular weakness.  

PubMed

The purpose of this prospective study was to evaluate the clinical and functional outcomes of THA using large-diameter metal-on-metal articulation in patients with neuromuscular weakness. Nineteen consecutive patients (19 hips) with neuromuscular weakness and displaced femoral neck fractures were enrolled. Functional improvement and recovery, radiological evaluation of THA and surgical morbidity were assessed. Mean Harris hip and WOMAC scores at final follow-up were 81.0 and 42.9, respectively. At final follow-up, no dislocation, metal hypersensitivity, or osteolysis was observed and no patient required revision of THA. The findings of this study indicate that the functional results of THA using large-diameter metal-on-metal articulation in patients with neuromuscular weakness can produce satisfactory outcomes with early functional recovery and a low dislocation rate. PMID:24051238

Park, Kyung-Soon; Seon, Jong-Keun; Lee, Keun-Bae; Yoon, Taek-Rim

2014-04-01

22

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

23

Metal-on-metal hip resurfacing compared with 28-mm diameter metal-on-metal total hip replacement: a randomised study with six to nine years' follow-up.  

PubMed

A total of 219 hips in 192 patients aged between 18 and 65 years were randomised to 28-mm metal-on-metal uncemented total hip replacements (THRs, 107 hips) or hybrid hip resurfacing (HR, 112 hips). At a mean follow-up of eight years (6.6 to 9.3) there was no significant difference between the THR and HR groups regarding rate of revision (4.0% (4 of 99) vs 5.8% (6 of 104), p = 0.569) or re-operation rates without revision (5.1% (5 of 99) vs 2.9% (3 of 104), p = 0.428). In the THR group one recurrent dislocation, two late deep infections and one peri-prosthetic fracture required revision, whereas in the HR group five patients underwent revision for femoral head loosening and one for adverse reaction to metal debris. The mean University of California, Los Angeles activity scores were significantly higher in HR (7.5 (sd 1.7) vs 6.9 (sd 1.7), p = 0.035), but similar mean Western Ontario and McMaster Universities Osteoarthritis Index scores were obtained (5.8 (sd 9.5) in HR vs 5.1 (sd 8.9) in THR, p = 0.615) at the last follow-up. Osteolysis was found in 30 of 81 THR patients (37.4%), mostly in the proximal femur, compared with two of 83 HR patients (2.4%) (p < 0.001). At five years the mean metal ion levels were < 2.5 ?g/l for cobalt and chromium in both groups; only titanium was significantly higher in the HR group (p = 0.001). Although revision rates and functional scores were similar in both groups at mid-term, long-term survival analysis is necessary to determine whether one procedure is more advantageous than the other. PMID:24151264

Vendittoli, P-A; Rivière, C; Roy, A G; Barry, J; Lusignan, D; Lavigne, M

2013-11-01

24

Metal-on-metal or metal-on-polyethylene for total hip arthroplasty: a meta-analysis of prospective randomized studies  

Microsoft Academic Search

Background  There has been recent concern regarding the increased use of metal-on-metal total hip arthroplasty (MOM-THA) as an alternative\\u000a to contemporary metal-on-polyethylene total hip arthroplasty (MOP-THA), and the choice remains controversial. We performed\\u000a a meta-analysis to evaluate and compare metal ion concentrations, complications, reoperation rates, clinical outcomes and\\u000a radiographic outcomes of MOM-THA and MOP-THA.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  We performed a systematic review of English

Xinhua Qu; Xiaolu Huang; Kerong Dai

25

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

26

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

27

Prevalence of a soft-tissue lesion after small head metal-on-metal total hip replacement: 13- to 19-year follow-up study.  

PubMed

We investigated the incidence of soft-tissue lesions after small head metal-on-metal total hip replacement (MoM THR). Between December 1993 and May 1999, 149 patients (195 hips) underwent primary cementless MoM THR. During the follow-up period, three patients (five THRs) died and eight patients (14 THRs) were lost to follow-up. We requested that all patients undergo CT evaluation. After exclusion of five patients (six THRs) who had undergone a revision procedure, and 22 (28 THRs) who were unwilling to take part in this study, 111 patients (142 THRs) were evaluated. There were 63 men (88 THRs) and 48 women (54 THRs) with a mean age of 45.7 years (37 to 56) at the time of surgery. The mean follow-up was 15.4 years (13 to 19). A soft-tissue lesion was defined as an abnormal peri-prosthetic collection of fluid, solid lesion or asymmetrical soft-tissue mass. At final follow-up, soft-tissue lesions were found in relation to 28 THRs (19.7%), including 25 solid and three cystic lesions. They were found in 20 men and eight women; 26 lesions were asymptomatic and two were symptomatic. The mean maximal diameter of the soft-tissue lesion was 42.3 mm (17 to 135). The relatively high rate of soft-tissue lesions observed with small head MoM THR remains a concern. PMID:25452360

Hwang, K T; Kim, Y H; Kim, Y S; Ryu, J A

2014-12-01

28

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

29

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

30

Metal Ion Levels and Functional Results Following Resurfacing Hip Arthroplasty Versus Conventional Small-Diameter Metal-on-Metal Total Hip Arthroplasty; a 3 to 5year Follow-Up of a Randomized Controlled Trial.  

PubMed

We present an update of a randomized controlled trial on 71 patients (<65years) who received either a resurfacing hip arthroplasty (RHA) (n=38) or cementless 28-mm metal-on-metal (MoM) total hip arthroplasty (THA) (n=33). Metal ion levels and functional outcome scores were analyzed with a mean follow-up of 58months (SD 8.1). No clear shifts in relatively good outcome was encountered between RHA and THA. Metal ion levels appear to equalize between groups after 3years. Median cobalt and chromium remained below 1.3?g/L throughout follow-up in both groups. Six revisions were performed, of which three for pseudotumor formation (one THA, two RHA). In conclusion there were no clinical differences between the two groups and metal ion levels were lower than other series remained low, however, pseudotumor formation was not eliminated. PMID:25172584

Bisseling, Pepijn; Smolders, José M H; Hol, Annemiek; van Susante, Job L C

2015-01-01

31

Silent soft tissue pathology is common with a modern metal-on-metal hip arthroplasty  

PubMed Central

Background and purpose Adverse reactions to metal debris have been reported to be a cause of pain in metal-on-metal hip arthroplasty. We assessed the incidence of both symptomatic and asymptomatic adverse reactions in a consecutive series of patients with a modern large-head metal-on-metal hip arthroplasty. Methods We studied the early clinical results and results of routine metal artifact-reduction MRI screening in a series of 79 large-head metal-on-metal hip arthroplasties (ASR; DePuy, Leeds, UK) in 68 patients. 75 hips were MRI scanned at mean 31 (12–52) months after surgery. Results 27 of 75 hips had MRI-detected metal debris-related abnormalities, of which 5 were mild, 18 moderate, and 4 severe. 8 of these hips have been revised, 6 of which were revised for an adverse reaction to metal debris, diagnosed preoperatively with MRI and confirmed histologically. The mean Oxford hip score (OHS) for the whole cohort was 21. It was mean 23 for patients with no MRI-based evidence of adverse reactions and 19 for those with adverse reactions detected by MRI. 6 of 12 patients with a best possible OHS of 12 had MRI-based evidence of an adverse reaction. Interpretation We have found a high early revision rate with a modern, large-head metal-on-metal hip arthroplasty. MRI-detected adverse rections to metal debris was common and often clinically “silent”. We recommend that patients with this implant should be closely followed up and undergo routine metal artifact-reduction MRI screening. PMID:21504335

2011-01-01

32

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

33

Self-reported neurological clinical manifestations of metal toxicity in metal-on-metal hip arthroplasty.  

PubMed

Adverse reactions to metal particle debris have been increasingly reported as a complication following large head metal-on-metal (MoM) hip arthroplasty. Elevated metal ion levels are a cause for concern. The aim of this study is to evaluate whether exposure to cobalt is associated with patient characteristics and symptoms of neuropathy, representing nervous system dysfunction. A cross-sectional study was conducted comparing patients with a MoM total hip arthroplasty and patients with a conventional hip arthroplasty. They received three questionnaires, one to assess neurotoxic complaints and two standardised self-administered questionnaires to identify symptoms that are suggestive of peripheral neuropathy. Current and historical data were available for whole blood cobalt levels in all patients. We analysed potential predictive factors for cobalt based on five different cut-off levels (0-2, 2-4, 4-10, 10-20, >20 µg/L). We performed 723 MoM total hip arthroplasties in 643 patients in our clinic. The response rate was 89%. Male-female ratio was 236/280, median age 63.6 years (30-72) with a mean follow-up of 50.6 months (20-86). We also sent the questionnaires to 98 patients in the control group. An increase in the incidence of reported symptoms was not consistent with higher serum cobalt levels. Female gender was the only consistent predictive factor for serum cobalt at different cobalt cut-off levels in the multivariate analysis. The study population did not show an increase in reported symptoms with elevated cobalt levels. Neurotoxic symptoms and whole blood cobalt levels did not show a consistent relationship with different dichotomised levels of cobalt exposure. PMID:25096449

van Lingen, Christiaan P; Ettema, Harmen B; Van Der Straeten, Catherine; Kollen, Bouwdewijn J; Verheyen, Cees C P M

2014-12-01

34

Metal on metal hip resurfacing arthroplasty  

Microsoft Academic Search

This paper explores the cost utility of metalon-metal hip resurfacing arthroplasty (MOM) as an alternative intervention to\\u000a total hip replacement or ‘watchful waiting’ for patients with advanced hip disease. Early implant failure among younger and\\u000a more active elderly patients can mean that the use of total hip replacement (THR) is delayed, with patients managed through\\u000a ‘watchful waiting’, a combination of

L. McKenzie; L. Vale; S. Stearns; K. McCormack

2003-01-01

35

The effectiveness of metal on metal hip resurfacing: a systematic review of the available evidence published before 2002  

Microsoft Academic Search

BACKGROUND: Conventional total hip replacement (THR) may be felt to carry too high a risk of failure over a patient's lifetime, especially in young people. There is increasing interest in metal on metal hip resurfacing arthroplasty (MoM) as this offers a bone-conserving option for treating those patients who are not considered eligible for THR. We aim to evaluate the effectiveness

Laura Wyness; Luke Vale; Kirsty McCormack; Adrian Grant; Miriam Brazzelli

2004-01-01

36

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

37

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

38

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

39

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

40

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

41

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

42

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

MedlinePLUS

... Surgeons Information about Soft Tissue Imaging and Metal Ion Testing Information for All Health Care Professionals who ... the implant and failure of the device. Metal ions from a metal-on-metal implant will enter ...

43

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

44

Effect of swing phase load on metal-on-metal hip lubrication, friction and wear.  

PubMed

There is renewed interest in metal-on-metal (MOM) total hip replacements (THRs), however, variable wear rates have been observed clinically. It is hypothesised that changes in soft tissue tensioning during surgery may alter loading of THRs during the swing phase of gait leading to changes in fluid film lubrication, friction and wear. This study aimed to assess the effect of swing phase load on the lubrication, friction and wear of MOM hip replacements. Theoretical lubrication modelling was carried out using elastohydrodynamic theory. All the governing equations were solved numerically for the lubricant film thickness between the articulating surfaces under the transient dynamic conditions with low and high swing phase loads. Friction testing was completed using a single axis pendulum simulator, simplified loading cycles were applied with low and high swing phase loads. MOM hip replacements were tested in a hip simulator, modified to provide different swing phase loading regimes; a low (100 N) and a high load (as per ISO 14242-1; 280 N). Results demonstrated that the performance of MOM bearings is highly dependent on swing phase load. Hence, changes in the tension of the tissues at surgery and variations in muscle forces may increase swing phase load, reduce lubrication, increase friction and accelerate wear. This may explain some of the variations that have been observed with clinical wear rates. PMID:16143337

Williams, Sophie; Jalali-Vahid, Davood; Brockett, Claire; Jin, Zhongmin; Stone, Martin H; Ingham, Eileen; Fisher, John

2006-01-01

45

'Pseudotumour' invading the proximal femur with normal metal ions following metal on metal hip resurfacing.  

PubMed

A 75-year-old woman who had undergone hybrid metal-on-metal hip resurfacing 8?years earlier underwent revision arthroplasty because of hip, groin and lateral thigh pain. The main differential was aseptic loosening; however, serum cobalt and chromium levels were normal. Multiple imaging modalities revealed a periprosthetic, cystic soft tissue mass adjacent to the proximal femur. A large 'pseudotumour' with proximal femoral invasion was found at revision arthroplasty. We report the first finding of a 'pseudotumour' invading the proximal femur with normal metal ions following metal on metal hip resurfacing. PMID:25670783

Krishnan, Harry; Sugand, Kapil; Ali, Ibrahim; Smith, Jay

2015-01-01

46

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

47

Metal allergy and second-generation metal-on-metal arthroplasties.  

PubMed

There are concerns about the induction of metal allergy with second-generation metal-on-metal prostheses, and the role that this may play in the development of complications such as 'pseudotumours' or failure of the implant. In this review, we attempt to set out the current knowledge on this subject. From a review of the literature, it is apparent that the first-generation metal-on-metal replacement hips did cause metal sensitization, and that joint failure was associated with this, although it is still not clear which one led to the other. Highly engineered second-generation metal-on-metal arthroplasties used in joint resurfacings are now increasingly employed. Several studies have recently shown an association between metal sensitization and peri-implant hypersensitivity reactions and implant loosening and failure, although the overall risk appears to be low. The pragmatic approach adopted by most contact dermatologists for patients known to be allergic to nickel, cobalt or chromium and who require joint replacement is to recommend prostheses made of titanium-based alloys. Patch testing continues to be a useful tool as laboratory investigations for metal hypersensitivity continue to emerge. The development of guidelines on the management of patients receiving metal-on-metal arthroplasties suspected of being metal-allergic is desirable. PMID:21957973

Cousen, Philippa J; Gawkrodger, David J

2012-02-01

48

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

49

Effects of metal-on-metal wear on the host immune system and infection in hip arthroplasty  

PubMed Central

Background and purpose Joint replacement with metal-on-metal (MOM) bearings have gained popularity in the last decades in young and active patients. However, the possible effects of MOM wear debris and its corrosion products are still the subject of debate. Alongside the potential disadvantages such as toxicity, the influences of metal particles and metal ions on infection risk are unclear. Methods We reviewed the available literature on the influence of degradation products of MOM bearings in total hip arthroplasties on infection risk. Results Wear products were found to influence the risk of infection by hampering the immune system, by inhibiting or accelerating bacterial growth, and by a possible antibiotic resistance and heavy metal co-selection mechanism. Interpretation Whether or not the combined effects of MOM wear products make MOM bearings less or more prone to infection requires investigation in the near future. PMID:20860450

2010-01-01

50

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

51

Retrieval Wear Analysis of Metal-on-Metal Hip Resurfacing Implants Revised Due to Pseudotumours  

Microsoft Academic Search

\\u000a Pseudotumours (soft-tissue masses relating to the hip joint) following metal-on-metal hip resurfacing arthroplasty (MoMHRA)\\u000a have been associated with elevated serum and hip aspirate metal ion levels, suggesting that pseudotumours occur when there\\u000a is increased wear. We aimed to quantify in vivo wear of implants revised for pseudotumours (8) and a control group of implants\\u000a (22) revised for other reasons of

Young-Min Kwon; Harinderjit S. Gill; David W. Murray; Amir Kamali

52

A retrieval analysis of explanted Durom metal-on-metal hip arthroplasties.  

PubMed

Given the recent reports of high failure rates, an improved understanding of the mechanism of failure of large diameter metal-on-metal hip arthroplasties is essential. We present clinical data and tribological analysis of a consecutive series of 74 failed large diameter metal-on-metal hips, comparing the Durom (Zimmer) with the Birmingham hip resurfacing (BHR) (Smith and Nephew). We retrospectively analysed pre-, intra-, and post-operative clinical data and measured the linear wear and component form of the explanted components using a roundness measuring machine. A significantly higher proportion of hips in the Durom group failed as a result of acetabular loosening (p=0.001) and this was supported by evidence of reduced bone in-growth on the backside of the cup. Comparison of roundness measurement revealed that the Durom hip was significantly lower wearing than the BHR (p<0.05) but the Durom femoral components were subject to significantly greater form errors (p<0.001), the pole of the head being flattened by up to 31 microns. Although the Durom hip is low wearing, reduced sphericity of the femoral component may have resulted in equatorial bearing, leading to an increased frictional torque at the cup-bone interface, preventing bone in-growth, and culminating in acetabular loosening. This supports recent clinical findings of high revision rates as a result of acetabular loosening for the Durom metal-on-metal hip system. PMID:22144337

Matthies, Ashley K; Henckel, Johann; Skinner, John A; Hart, Alister J

2011-01-01

53

The effect of the metal-on-metal hip controversy on Internet search activity.  

PubMed

The recall of the articular surface replacement (ASR) hip prosthesis in 2010 represents one of the most controversial areas in orthopaedic surgery in recent years. The aim of this study was to compare the impact of the metal-on-metal hip controversy on Internet search activity in four different regions and determine whether the number of related news reports affected Internet search activity. The Google Trends, Keywords and News applications were used to record the number of news articles and Internet search activity for the terms "hip recall", "metal-on-metal hip" and "ASR hip" from October 2009 to October 2012 in the USA, the UK, Australia and Ireland. There was a large increase in search activity following the official recall in August 2010 in all countries. There was significantly greater search activity after the recall in Ireland compared with the UK for the search term "hip recall" (P = 0.004). For the term "metal-on-metal hip", the UK had significantly more search activity (P = 0.0009). There was a positive correlation between the number of news stories in UK and Ireland with Internet search activity but not in the USA or Australia. Differences between countries affected by the same recall highlight the complex effects of the media on public awareness. The data demonstrates a window of opportunity prior to the official recall for the development of an awareness campaign to provide patients with accurate information. PMID:24390041

Phelan, Nigel; Kelly, John C; Kenny, Patrick

2014-10-01

54

Metal-on-metal local tissue reaction is associated with corrosion of the head taper junction.  

PubMed

We evaluated taper corrosion in 36-mm diameter metal-on-metal (MOM) and metal-on-polyethylene (MOP) femoral heads from a single manufacturer retrieved for various reasons. Three reviewers visually graded taper corrosion with a 5-point scale on 19 MOM heads and 14 MOP heads. The MOM group had a higher corrosion score than the MOP group (mean, 3.5 vs 1.9; P < .001). There were 8 MOM heads (42%) and only 1 MOP head (7%) that demonstrated corrosion outside of the taper zone. Metal-on-metal patients revised secondary to adverse local tissue reactions (ALTRs) had greater scores than patients without ALTRs (mean, 4.36 vs 2.38; P < .01). Adverse local tissue reactions MOM patients were also likely to have corrosion outside of the taper junction. The corrosion score increased with implantation time, and at all time intervals, the corrosion score for the MOM group was greater. Because corrosion worsens with time, we are concerned that MOM ALTR failures will increase with longer follow-up. PMID:22554728

Fricka, Kevin B; Ho, Henry; Peace, William J; Engh, Charles A

2012-09-01

55

Subsurface microstructure of metal-on-metal hip joints and its relationship to wear particle generation.  

PubMed

To control and minimize wear of metal-on-metal hip joints it is essential to understand the mechanisms of debris generation. In vivo, mainly nanosize globular and needle-shaped particles are found. These can neither stem from the action of abrasion nor from tribochemical reactions. In this study the acting wear mechanisms have been first identified on the surface by means of scanning electron microscopy (SEM). Afterwards, the microstructures of the subsurface regions of explants have been investigated using a transmission electron microscope (TEM). Observation of the subsurface gave additional insight about the microstructural changes of cobalt-base alloys subjected to wear. At some distance from the surface, a network of stacking faults and hexagonal epsilon-martensite was found strengthening the bulk material. This microstructure changed into a nanocrystalline type moving closer towards the surface. A comparison of in vivo debris size and grain size of the surface suggests that the globular wear particles result from torn off nanocrystals, while the needle shaped particles are generated by fractured epsilon-martensite. Identified cracks, propagating through the nanocrystalline layer, further support these findings. Thus, it is suggested that the dominating mechanism of particle generation for metal-on-metal joints is surface fatigue within a nanocrystalline surface layer. PMID:15497166

Büscher, R; Täger, G; Dudzinski, W; Gleising, B; Wimmer, M A; Fischer, A

2005-01-15

56

The effect of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants.  

PubMed

The influence of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants was investigated in a boundary lubrication regime designed to represent the conditions that occurred some of the time in vivo. These cobalt-chromium-molybdenum alloys were either wrought, with a total carbon content of 0.05 or 0.23 wt %, cast with a solution-annealing procedure or simply as-cast but not solution annealed. Bars of these different alloy grades were subjected to various heat treatments to develop different microstructures. The wear was evaluated in a linear-tracking reciprocating pin-on-plate apparatus with a 25 per cent bovine serum lubricant. The wear was found to be strongly affected by the dissolved carbon content of the alloys and mostly independent of grain size or the carbide characteristics. The increased carbon in solid solution caused reductions in volumetric wear because carbon helped to stabilize a face-centred cubic crystal structure, thus limiting the amount of strain-induced transformation to a hexagonal close-packed crystal structure. Based on the observed surface twining in and around the contact zone and the potentially detrimental effect of the hexagonal close-packed phase, it was postulated that the wear of cobalt-based alloys in the present study was controlled by a deformation mechanism. PMID:16669383

Varano, R; Bobyn, J D; Medley, J B; Yue, S

2006-02-01

57

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

58

Novel method for characterization and compensation for canopy distortion over a large head box  

NASA Astrophysics Data System (ADS)

Thales Visionix, a wholly owned subsidiary of Thales Communications, Inc., has developed a novel method for characterization of canopy distortion for a large head box. Canopy distortion occurs when the user is looking through any curved transparency. Any helmet mounted display system must either compensate for this distortion, or add canopy distortion error to its total error budget. To date, canopies have been characterized for only a few discrete locations in the cockpit. This results in a dilution of canopy distortion compensation as the pilot will rarely sit in one of the few defined locations. The method described herein allows for canopy distortion characterization and compensation for the entire HMD head-box.

Atac, Robert; Fischler, Mark

2013-05-01

59

What happens to serum metal ion levels after a metal-on-metal bearing is removed?  

PubMed

Serum cobalt (Co) and chromium (Cr) levels are commonly used to screen for excessive wear of metal-on-metal hip replacements. However, it is unknown how rapidly these should decline after revision. 25 patients with average Co and Cr ion levels of 56.3 ?g/L and 20.5 ?g/L were followed with serial ion level testing post-revision. Over the first 6 weeks post-revision, the rate of decline for Co and Cr was approximately 2% per day and this slowed to approximately 1% decline per day over the ensuing 6 weeks. This translated to a decline of approximately 80% from the starting value after 6 weeks and a decline of approximately 90% after 12 weeks post-revision. The rate of decline for both Co and Cr was significantly faster during the first 6 weeks (P<0.001). In patients with ultra-high Cr levels>20 ?g/L, the rate of Cr decline is less predictable and may be protracted leading to persistent elevation above 5 ?g/L for one year or more post-revision in some cases. PMID:23948123

Ball, Scott T; Severns, Dustyn; Linn, Michael; Meyer, R Scott; Swenson, F Craig

2013-09-01

60

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

61

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

62

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

63

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

64

Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study.  

PubMed

We have updated our previous randomised controlled trial comparing release of chromium (Cr) and cobalt (Co) ions and included levels of titanium (Ti) ions. We have compared the findings from 28 mm metal-on-metal total hip replacement, performed using titanium CLS/Spotorno femoral components and titanium AlloFit acetabular components with Metasul bearings, with Durom hip resurfacing using a Metasul articulation or bearing and a titanium plasma-sprayed coating for fixation of the acetabular component. Although significantly higher blood ion levels of Cr and Co were observed at three months in the resurfaced group than in total hip replacement, no significant difference was found at two years post-operatively for Cr, 1.58 microg/L and 1.62 microg/L respectively (p = 0.819) and for Co, 0.67 microg/L and 0.94 microg/L respectively (p = 0.207). A steady state was reached at one year in the resurfaced group and after three months in the total hip replacement group. Interestingly, Ti, which is not part of the bearing surfaces with its release resulting from metal corrosion, had significantly elevated ion levels after implantation in both groups. The hip resurfacing group had significantly higher Ti levels than the total hip replacement group for all periods of follow-up. At two years the mean blood levels of Ti ions were 1.87 microg/L in hip resurfacing and and 1.30 microg/L in total hip replacement (p = 0.001). The study confirms even with different bearing diameters and clearances, hip replacement and 28 mm metal-on-metal total hip replacement produced similar Cr and Co metal ion levels in this randomised controlled trial study design, but apart from wear on bearing surfaces, passive corrosion of exposed metallic surfaces is a factor which influences ion concentrations. Ti plasma spray coating the acetabular components for hip resurfacing produces significantly higher release of Ti than Ti grit-blasted surfaces in total hip replacement. PMID:20044673

Vendittoli, P-A; Roy, A; Mottard, S; Girard, J; Lusignan, D; Lavigne, M

2010-01-01

65

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

66

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

67

Effect of head size on wear properties of metal-on-metal bearings of hip prostheses, and comparison with wear properties of metal-on-polyethylene bearings using hip simulator.  

PubMed

The effects of articular head size on the wear losses of the metal insert and articular head for a metal-on-metal bearing were examined using a hip simulator manufactured to satisfy ISO 14242-1. The wear properties of metal-on-metal and metal-on-polyethylene bearings were also compared under the same conditions. The total wear losses of the metal insert and articular head decreased with increasing diameter of the metal insert in the range from 28 to 44mm. The total wear loss was greater for a diameter of 48mm than for a diameter of 44mm. When the articular metal insert diameter was smaller than 44mm, the wear loss was reduced because the contact surface pressure increased with increasing metal insert diameter. However, the increase in wear loss observed for the 48-mm-diameter insert might have been due to the considerable increase in the rotation moment with increasing insert diameter. The tendency of decreasing contact pressure calculated using the Hertzian contact stress equation nearly conformed to the change in wear loss. On the other hand, the wear loss of an artificial hip joint consisting of a cross-linked ultrahigh-molecular-weight polyethylene insert (UHMWPE) and a Co-Cr-Mo articular head was small. PMID:24290355

Okazaki, Yoshimitsu

2014-03-01

68

Electrochemical instrumentation of a hip simulator: a new tool for assessing the role of corrosion in metal-on-metal hip joints.  

PubMed

Polyethylene wear debris induced osteolysis has triggered investigations to find alternative material combinations to the well-established metal-on-polyethylene hip implants. Owing to some early successful clinical cases, metal-on-metal (MoM) hip replacements have been attracting more and more interest. There is, however, considerable concern about the propensity of MoM hip replacements to release metal ions and fine, nanometre-scale metallic wear debris. The long-term effect from released metal ions and wear particles is still not clear. To date, all the work on hip simulators focused on assessing mass losses damage has been referred to as 'wear'. However, it is known in the field of tribocorrosion that mechanical removal of the passive layer on Co-Cr alloys can significantly enhance corrosion activity. In total joint replacements, it is possible that corrosion plays a significant role. However, no one has ever tried to extract, on a hip simulator, what proportion of the damage is due to mechanical processes and the corrosion processes. This paper describes the first instrumentation of an integrated hip joint simulator to provide in-situ electrochemical measurements in real time. The open circuit potential results are reported to assess the corrosion regime in the absence and presence of movement at the bearing surfaces. The importance of these measurements is that the real damage mechanisms can be assessed as a function of the operating cycle. PMID:21218689

Yan, Y; Neville, A; Dowson, D; Williams, S; Fisher, J

2010-11-01

69

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

70

Component size mismatch of metal on metal hip arthroplasty: an avoidable never event.  

PubMed

Size mismatch of components used in total hip arthroplasty is a serious, preventable patient safety incident of unknown prevalence as many cases are not detected. Component size mismatch was found in 11 cases (0.9%) at our retrieval centre. All cases of mismatch were not detected on plain radiograph during routine clinical follow up and blood metal ion levels were elevated above the MHRA action level of 7 ppb. Root cause analysis identified manufacturer, hospital and surgeon factors that need to be addressed to reduce the incidence of this avoidable clinical problem. Retrieval analysis is the only method of confirming size mismatch and is likely to be under-represented in National Joint Registries that record the indication for revision at the time of revision. PMID:24726175

Whittaker, Robert K; Hexter, Adam; Hothi, Harry S; Panagiotidou, Anna; Bills, Paul J; Skinner, John A; Hart, Alister J

2014-08-01

71

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.

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

2012-01-01

72

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

73

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

74

Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre: A study using the NJR dataset.  

PubMed

Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67 045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data. Cite this article: Bone Joint J 2015;97-B:10-18. PMID:25568407

Sabah, S A; Henckel, J; Cook, E; Whittaker, R; Hothi, H; Pappas, Y; Blunn, G; Skinner, J A; Hart, A J

2015-01-01

75

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

76

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

77

Predictors of time to revision and clinical outcomes following revision of metal-on-metal hip replacements for adverse reaction to metal debris.  

PubMed

We undertook a retrospective cohort study to determine clinical outcomes following the revision of metal-on-metal (MoM) hip replacements for adverse reaction to metal debris (ARMD), and to identify predictors of time to revision and outcomes following revision. Between 1998 and 2012 a total of 64 MoM hips (mean age at revision of 57.8 years; 46 (72%) female; 46 (72%) hip resurfacings and 18 (28%) total hip replacements) were revised for ARMD at one specialist centre. At a mean follow-up of 4.5 years (1.0 to 14.6) from revision for ARMD there were 13 hips (20.3%) with post-operative complications and eight (12.5%) requiring re-revision. The Kaplan-Meier five-year survival rate for ARMD revision was 87.9% (95% confidence interval 78.9 to 98.0; 19 hips at risk). Excluding re-revisions, the median absolute Oxford hip score (OHS) following ARMD revision using the percentage method (0% best outcome and 100% worst outcome) was 18.8% (interquartile range (IQR) 7.8% to 48.3%), which is equivalent to 39/48 (IQR 24.8/48 to 44.3/48) when using the modified OHS. Histopathological response did not affect time to revision for ARMD (p = 0.334) or the subsequent risk of re-revision (p = 0.879). Similarly, the presence or absence of a contralateral MoM hip bearing did not affect time to revision for ARMD (p = 0.066) or the subsequent risk of re-revision (p = 0.178). Patients revised to MoM bearings had higher rates of re-revision (five of 16 MoM hips re-revised; p = 0.046), but those not requiring re-revision had good functional results (median absolute OHS 14.6% or 41.0/48). Short-term morbidity following revision for ARMD was comparable with previous reports. Caution should be exercised when choosing bearing surfaces for ARMD revisions. PMID:25452361

Matharu, G S; Pynsent, P B; Sumathi, V P; Mittal, S; Buckley, C D; Dunlop, D J; Revell, P A; Revell, M P

2014-12-01

78

(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

79

Activation of Noble Metals on Metal-Carbide Surfaces: Novel Catalysts for CO Oxidation, Desulfurization and Hydrogenation Reactions  

SciTech Connect

This perspective article focuses on the physical and chemical properties of highly active catalysts for CO oxidation, desulfurization and hydrogenation reactions generated by depositing noble metals on metal-carbide surfaces. To rationalize structure-reactivity relationships for these novel catalysts, well-defined systems are required. High-resolution photoemission, scanning tunneling microscopy (STM) and first-principles periodic density-functional (DF) calculations have been used to study the interaction of metals of Groups 9, 10 and 11 with MC(001) (M = Ti, Zr, V, Mo) surfaces. DF calculations give adsorption energies that range from 2 eV (Cu, Ag, Au) to 6 eV (Co, Rh, Ir). STM images show that Au, Cu, Ni and Pt grow on the carbide substrates forming two-dimensional islands at very low coverage, and three-dimensional islands at medium and large coverages. In many systems, the results of DF calculations point to the preferential formation of admetal-C bonds with significant electronic perturbations in the admetal. TiC(001) and ZrC(001) transfer some electron density to the admetals facilitating bonding of the adatom with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). For example, the Cu/TiC(001) and Au/TiC(001) systems are able to cleave both S-O bonds of SO{sub 2} at a temperature as low as 150 K, displaying a reactivity much larger than that of TiC(001) or extended surfaces of bulk copper and gold. At temperatures below 200 K, Au/TiC is able to dissociate O{sub 2} and perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(001) or Au(111), a Au/TiC(001) surface displays an activity for the hydrodesulfurization of thiophene higher than that of conventional Ni/MoS{sub x} catalysts. In general, the Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces. Thus, metal carbides are excellent supports for enhancing the chemical reactivity of noble metals.

Rodriguez J. A.; Illas, F.

2012-01-01

80

High incidence of loosening at 5-year follow-up of a cemented metal-on-metal acetabular component in THR  

Microsoft Academic Search

Introduction  High rates of polyethylene wear in metal-on-polyethylene-bearing surfaces correlate with peri-prosthetic osteolysis and early\\u000a loosening. Hard-bearing surfaces have been used as they may decrease the production of debris and improve survival of the\\u000a prosthesis. The aim of this study is to ascertain the rate of early loosening of a polyethylene cemented acetabular component\\u000a with a metal-on-metal (MOM) insert.\\u000a \\u000a \\u000a \\u000a Methods  Between 1997

S. Descamps; B. Bouillet; S. Boisgard; J. P. Levai

2009-01-01

81

Optimal acetabular component orientation estimated using edge-loading and impingement risk in patients with metal-on-metal hip resurfacing arthroplasty.  

PubMed

Edge-loading in patients with metal-on-metal resurfaced hips can cause high serum metal ion levels, the development of soft-tissue reactions local to the joint called pseudotumours and ultimately, failure of the implant. Primary edge-loading is where contact between the femoral and acetabular components occurs at the edge/rim of the acetabular component whereas impingement of the femoral neck on the acetabular component's edge causes secondary or contrecoup edge-loading. Although the relationship between the orientation of the acetabular component and primary edge-loading has been identified, the contribution of acetabular component orientation to impingement and secondary edge-loading is less clear. Our aim was to estimate the optimal acetabular component orientation for 16 metal-on-metal hip resurfacing arthroplasty (MoMHRA) subjects with known serum metal ion levels. Data from motion analysis, subject-specific musculoskeletal modelling and Computed Tomography (CT) measurements were used to calculate the dynamic contact patch to rim (CPR) distance and impingement risk for 3416 different acetabular component orientations during gait, sit-to-stand, stair descent and static standing. For each subject, safe zones free from impingement and edge-loading (CPR <10%) were defined and, consequently, an optimal acetabular component orientation was determined (mean inclination 39.7° (SD 6.6°) mean anteversion 14.9° (SD 9.0°)). The results of this study suggest that the optimal acetabular component orientation can be determined from a patient's motion and anatomy. However, 'safe' zones of acetabular component orientation associated with reduced risk of dislocation and pseudotumour are also associated with a reduced risk of edge-loading and impingement. PMID:25482661

Mellon, Stephen J; Grammatopoulos, George; Andersen, Michael S; Pandit, Hemant G; Gill, Harinderjit S; Murray, David W

2015-01-21

82

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

83

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

84

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

85

The relationship between the angle of version and rate of wear of retrieved metal-on-metal resurfacings: a prospective, CT-based study.  

PubMed

We measured the orientation of the acetabular and femoral components in 45 patients (33 men, 12 women) with a mean age of 53.4 years (30 to 74) who had undergone revision of metal-on-metal hip resurfacings. Three-dimensional CT was used to measure the inclination and version of the acetabular component, femoral version and the horizontal femoral offset, and the linear wear of the removed acetabular components was measured using a roundness machine. We found that acetabular version and combined version of the acetabular and femoral components were weakly positively correlated with the rate of wear. The acetabular inclination angle was strongly positively correlated with the rate of wear. Femoral version was weakly negatively correlated with the rate of wear. Application of a threshold of > 5 ?m/year for the rate of wear in order to separate the revisions into low or high wearing groups showed that more high wearing components were implanted outside Lewinnek's safe zone, but that this was mainly due to the inclination of the acetabular component, which was the only parameter that significantly differed between the groups. We were unable to show that excess version of the acetabular component alone or combined with femoral version was associated with an increase in the rate of wear based on our assessment of version using CT. PMID:21357951

Hart, A J; Ilo, K; Underwood, R; Cann, P; Henckel, J; Lewis, A; Cobb, J; Skinner, J

2011-03-01

86

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

87

Asymptomatic prospective and retrospective cohorts with metal-on-metal hip arthroplasty indicate acquired lymphocyte reactivity varies with metal ion levels on a group basis  

PubMed Central

Some tissues from metal-on-metal (MoM) hip arthroplasty revisions have shown evidence of adaptive-immune reactivity (i.e., excessive peri-implant lymphocyte infiltration/activation). We hypothesized that, prior to symptoms, some people with MoM hip arthroplasty will develop quantifiable metal-induced lymphocyte reactivity responses related to peripheral metal ion levels. We tested 3 cohorts (Group-1: n=21 prospective longitudinal MoM hip arthroplasty; Group-2: n=17 retrospective MoM hip arthroplasty; and Group-3: n=20 controls without implants). We compared implant position, metal-ion release, and immuno-reactivity. MoM cohorts had elevated (p<0.01) amounts of serum Co and Cr compared to controls as early as 3 mos post-op (Group-1:1.2ppb-Co, 1.5ppb-Cr; Group-2: 3.4ppb-Co,, 5.4ppb-Cr; Group-3: 0.01ppb-Co, 0.1ppb-Cr). However, only after 1 to 4 yrs post-op did 56% of Group-1 develop metal-reactivity (vs. 5%pre-op, metal-LTT, SI>2), compared with 76% of Group-2 and 15% of Group-3 controls (patch testing was a poor diagnostic indicator with only 1/21 Group-1 positive). Higher cup-abduction angles (50° vs. 40°) in Group-1 were associated with higher serum Cr (p<0.07). However, sub-optimal cup-anteversion angles (9° vs. 20°) had higher serum Co (p<0.08). Serum Cr and Co were significantly elevated in reactive vs. non-reactive Group-1 participants (p<0.04). CD4+CD69+ T-helper lymphocytes (but not CD8+) and IL-1?, IL-12 and IL-6 cytokines were all significantly elevated in metal-reactive vs. non-reactive Group-1 participants. Our results showed that lymphocyte reactivity to metals can develop within the first 1 to 4 years after MoM arthroplasty in asymptomatic patients and lags increases in metal ion levels. This increased metal reactivity was more prevalent in those individuals with extreme cup angles and higher amounts of circulating metal. PMID:22941579

Hallab, NJ; Caicedo, M; McAllister, K; Skipor, A; Amstutz, H; Jacobs, JJ

2012-01-01

88

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

89

Metal ion release after total hip replacement.  

PubMed

The concentration of cobalt (Co), chromium (Cr), molybdenum (Mo), nickel (Ni), iron (Fe) and zinc (Zn) was measured using neutron activation analysis in tissue taken from an 81 year old female at necropsy. The patient had bilateral cobalt chromium molybdenum (Co-Cr-Mo) total hip replacements: one, a metal-on-metal had been in place for 14 years, the other a metal-on-plastic for 5.5 years. Although the metal-on-metal side had become painful, the patient remained active until she died. The measurements indicated that the concentrations of Co and Cr in the lung, kidney, liver and spleen were up to fifty times "Standard Man" values. High values occurred also in the urine and in the hair. The tissue adjacent to the metal-on-metal joint was heavily laden with metal wear debris, whereas that adjacent to the metal-on-plastic joint was relatively uncontaminated. The concentration varied with distance from the implant. Co predominated in the urine, whereas Cr predominated near the implants. The existence of such high levels, especially in the organs, is a possible cause for concern. PMID:7470573

Dobbs, H S; Minski, M J

1980-10-01

90

Reconstruction of large head and neck deformities: experience with free gracilis muscle and myocutaneous flaps.  

PubMed

Microvascular free flaps continue to revolutionize coverage options in head and neck reconstruction. The authors describe their experience with the gracilis free flap and the myocutaneous gracilis free flap with reconstruction of head and neck defects. Eleven patients underwent 12 free tissue transfer to the head and neck region. The reconstruction was performed with the transverse myocutaneous gracilis (TMG) flap (n = 7) and the gracilis muscle flap with skin graft (n = 5). The average patient age was 63.4 years (range, 17-82 years). The indications for this procedure were tumor and haemangioma resections. The average patient follow-up was 20.7 months (range, 1 month-5.7 years). Total flap survival was 100%. There were no partial flap losses. Primary wound healing occurred in all cases. Recipient site morbidities included one hematoma. In our experience for reconstruction of moderate volume and surface area defects, muscle flaps with skin graft provide a better color match and skin texture relative to myocutaneous or fasciocutaneous flaps. The gracilis muscle free flap is not widely used for head and neck reconstruction but has the potential to give good results. As a filling substance for large cavities, the transverse myocutaneus gracilis flap has many advantages including reliable vascular anatomy, relatively great plasticity and a concealed donor area. PMID:19957312

Del Frari, Barbara; Schoeller, Thomas; Wechselberger, Gottfried

2010-01-01

91

Resurfacing is Comparable to Total Hip Arthroplasty at Short-term Followup  

Microsoft Academic Search

Metal-on-metal total hip resurfacing arthroplasty has had excellent reported results at early to midterm followup, and some\\u000a studies suggest that outcomes are comparable to conventional THA. We compared the clinical and radiographic outcomes of two\\u000a closely matched groups of 54 patients who underwent resurfacing and conventional THA, respectively. Each group consisted of\\u000a 36 men and 18 women who had a

Michael A. Mont; David R. Marker; Jonathan M. Smith; Slif D. Ulrich; Mike S. McGrath

2009-01-01

92

CoCr wear particles generated from CoCr alloy metal-on-metal hip replacements, and cobalt ions stimulate apoptosis and expression of general toxicology-related genes in monocyte-like U937 cells.  

PubMed

Cobalt-chromium (CoCr) particles in the nanometre size range and their concomitant release of Co and Cr ions into the patients' circulation are produced by wear at the articulating surfaces of metal-on-metal (MoM) implants. This process is associated with inflammation, bone loss and implant loosening and led to the withdrawal from the market of the DePuy ASR™ MoM hip replacements in 2010. Ions released from CoCr particles derived from a resurfacing implant in vitro and their subsequent cellular up-take were measured by ICP-MS. Moreover, the ability of such metal debris and Co ions to induce both apoptosis was evaluated with both FACS and immunoblotting. qRT-PCR was used to assess the effects on the expression of lymphotoxin alpha (LTA), BCL2-associated athanogene (BAG1), nitric oxide synthase 2 inducible (NOS2), FBJ murine osteosarcoma viral oncogene homolog (FOS), growth arrest and DNA-damage-inducible alpha (GADD45A). ICP-MS showed that the wear debris released significant (p<0.05) amounts of Co and Cr ions into the culture medium, and significant (p<0.05) cellular uptake of both ions. There was also an increase (p<0.05) in apoptosis after a 48h exposure to wear debris. Analysis of qRT-PCR results found significant up-regulation (p<0.05) particularly of NOS2 and BAG1 in Co pre-treated cells which were subsequently exposed to Co ions+debris. Metal debris was more effective as an inducer of apoptosis and gene expression when cells had been pre-treated with Co ions. This suggests that if a patient receives sequential bilateral CoCr implants, the second implant may be more likely to produce adverse effects than the first one. PMID:25281833

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

2014-10-01

93

Effect of femoral head size on risk of revision for dislocation after total hip arthroplasty  

PubMed Central

Background and purpose Previous population-based registry studies have shown that larger femoral head size is associated with reduced risk of revision for dislocation. However, the previous data have not included large numbers of hip resurfacing arthroplasties or large metal-on-metal (> 36-mm) femoral head arthroplasties. We evaluated the association between femoral component head size and the risk of revision for dislocation after THA by using Finnish Arthroplasty Register data. Patients and methods 42,379 patients who were operated during 1996–2010 fulfilled our criteria. 18 different cup/stem combinations were included. The head-size groups studied (numbers of cases) were 28 mm (23,800), 32 mm (4,815), 36 mm (3,320), and > 36 mm (10,444). Other risk factors studied were sex, age group (18–49 years, 50–59 years, 60–69 years, 70–79 years, and > 80 years), and time period of operation (1996–2000, 2001–2005, 2006–2010). Results The adjusted risk ratio in the Cox model for a revision operation due to dislocation was 0.40 (95% CI: 0.26–0.62) for 32-mm head size, 0.41 (0.24–0.70) for 36-mm head size, and 0.09 (0.05–0.17) for > 36-mm head size compared to implants with a head size of 28 mm. Interpretation Larger femoral heads clearly reduce the risk of dislocation. The difference in using heads of > 36 mm as opposed to 28-mm heads for the overall revision rate at 10 years follow-up is about 2%. Thus, although attractive from a mechanical point of view, based on recent less favorable clinical outcome data on these large heads, consisting mainly of metal-on-metal prostheses, one should be cautious using these implants. PMID:23799348

Kostensalo, Inari; Junnila, Mika; Virolainen, Petri; Remes, Ville; Matilainen, Markus; Vahlberg, Tero; Pulkkinen, Pekka; Eskelinen, Antti; Mäkelä, Keijo T

2013-01-01

94

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

95

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

96

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

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, T?, L?)-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, T?, L?)-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

2014-10-01

97

Dual-mobility acetabular components in total hip arthroplasty.  

PubMed

With dislocation being one of the most serious complications of total hip arthroplasty, prevention of recurrent instability has been the driving force behind several implant designs, including large-diameter heads, metal-on-metal bearing surfaces, and constrained acetabular components. Dual-articulation acetabular component design was similarly conceived in an effort to reduce postoperative dislocation risk. This design, developed in France in 1975 and popularized in Europe, was recently approved in the United States and represents a new surgical option for United States orthopedic surgeons performing total hip arthroplasty. In this article, we review the dual-articulation design in terms of its history, biomechanical concepts, published indications, contraindications, outcomes, and complications based on more than 20 years of largely French clinical experience. PMID:24278908

McArthur, Benjamin A; Nam, Denis; Cross, Michael B; Westrich, Geoffrey H; Sculco, Thomas P

2013-10-01

98

Metal ion levels in large-diameter total hip and resurfacing hip arthroplasty-Preliminary results of a prospective five year study after two years of follow-up  

PubMed Central

Background Metal-on-metal hip resurfacing is an alternative to metal-on-metal total hip arthroplasty, especially for young and physically active patients. However, wear which might be detected by increased serum ion levels is a matter of concern. Methods The aims of this preliminary study were to determine the raise of metal ion levels at 2-years follow-up in a prospective setting and to evaluate differences between patients with either resurfacing or total hip arthroplasty. Furthermore we investigated if the inclination of the acetabular component and the arc of cover would influence these findings. Therefore, 36 patients were followed prospectively. Results The results showed increments for Co and Cr in both implant groups. Patients treated with large-diameter total hip arthroplasty showed fourfold and threefold, respectively, higher levels for Co and Cr compared to the resurfacing group (Co: p?metal-on-metal hip replacement. PMID:22494794

2012-01-01

99

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

100

Making A Noble-Metal-On-Metal-Oxide Catalyst  

NASA Technical Reports Server (NTRS)

Catalyst exhibits superior performance in oxidation of CO in CO2 lasers. Two-step process developed for preparing platinum- or palladium-on-tin-oxide catalyst for recombination of CO and O2, decomposition products that occur in high-voltage discharge region of closed-cycle CO2 laser. Process also applicable to other noble-metal/metal-oxide combinations.

Miller, Irvin M.; Davis, Patricia P.; Upchurch, Billy T.

1989-01-01

101

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. ...

102

Implication of femoral stem on performance of articular surface replacement (ASR) XL total hip arthroplasty.  

PubMed

Taper junctions of large diameter metal-on-metal femoral heads and femoral stems were described as metal ion generator due to accelerated wear and corrosion. However, literature about the Articular Surface Replacement (ASR) total hip arthroplasty (THA) invariably deals with stems manufactured by DePuy Orthopedics (Warsaw, IN, USA). Nothing is known whether different stems with common 12/14 mm tapers affect failure rate or ion release. 99 ASR THA (88 patients) implanted with CoxaFit or ARGE Geradschaft stems (K-Implant, Hannover, Germany) were retrospectively analyzed. After a mean follow-up of 3.5 years revision rate was 24.5%, mostly due to adverse reaction to metal debris (ARMD). CT scan revealed component loosening in 10.3% and pseudotumoral lesions in 12.6%. Elevated ion concentrations (>7 ?g/l) were found in 38.6%. PMID:25108735

Cip, Johannes; von Strempel, Archibald; Bach, Christian; Luegmair, Matthias; Benesch, Thomas; Martin, Arno

2014-11-01

103

TOTAL Full-TOTAL Full-  

E-print Network

- X TOTAL Full- Part- X TOTAL Alternative Energy 6 . . 6 11 . . 11 13 2 . 15 Biomedical Engineering 52 English 71 . 4 75 70 . 4 74 72 . 3 75 Geosciences 9 . 1 10 15 . . 15 19 . . 19 History 37 1 2 40 28 3 3 34

Portman, Douglas

104

Polyethylene Wear in Retrieved Reverse Total Shoulder Components  

PubMed Central

Background Reverse total shoulder arthroplasty has been used to treat rotator cuff tear arthropathy, proximal humeral fractures and for failed conventional total shoulder prostheses. It has been suggested that polyethylene wear is potentially higher in reverse shoulder replacements than in conventional shoulder replacements. The modes and degree of polyethylene wear have not been completely elucidated. The purpose of this study was to evaluate polyethylene wear patterns in seven specimens retrieved at revision arthroplasty and identify factors that may be associated with increased wear. Methods Reverse total shoulder components were retrieved from 7 patients during revision arthroplasty for loosening and/or pain. Pre-operative glenoid tilt and placement, and scapular notching were evaluated using pre-operative radiographs. Polyethylene wear was evaluated using microCT and optical microscopy. Results Wear on the rim of the polyethylene humeral cup, was identified on all retrieved components. The extent of rim wear varied from a penetration depth of 0.1 to 4.7 mm. We could not demonstrate a correlation between scapular notching and rim wear. However, rim wear was more extensive when the inferior screw had made contact with the liner. Metal on metal wear between the humeral component and the inferior screw of one component was also observed. Wear of the intended bearing surface was minimal. Discussion Rim damage was the predominant cause of polyethylene wear in our retrieved specimens. Direct contact between the humeral component and inferior metaglene screws is concerning because this could lead to accelerated UHMWPE wear and also induce mechanical loosening of the glenoid component. PMID:21724419

Day, Judd S; MacDonald, Daniel W; Olsen, Madeline; Getz, Charles; Williams, Gerald R; Kurtz, Steven M

2011-01-01

105

Alumina-on-alumina total hip replacement for femoral neck fracture in healthy patients  

PubMed Central

Background Total hip replacement is considered the best option for treatment of displaced intracapsular fractures of the femoral neck (FFN). The size of the femoral head is an important factor that influences the outcome of a total hip arthroplasty (THA): implants with a 28 mm femoral head are more prone to dislocate than implants with a 32 mm head. Obviously, a large head coupled to a polyethylene inlay can lead to more wear, osteolysis and failure of the implant. Ceramic induces less friction and minimal wear even with larger heads. Methods A total of 35 THAs were performed for displaced intracapsular FFN, using a 32 mm alumina-alumina coupling. Results At a mean follow-up of 80 months, 33 have been clinically and radiologically reviewed. None of the implants needed revision for any reason, none of the cups were considered to have failed, no dislocations nor breakage of the ceramic components were recorded. One anatomic cementless stem was radiologically loose. Conclusions On the basis of our experience, we suggest that ceramic-on-ceramic coupling offers minimal friction and wear even with large heads. PMID:21284879

2011-01-01

106

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

107

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

108

Supporting Online Material for Graphitic Tribological Layers in Metal-on-Metal Hip Replacements  

E-print Network

a precision cut-off-machine (Accutom-5, Struers) cooled by distilled water. During all handling, care components. The use of electron beam and ion beam was kept minimal. The thin film was subsequently

Marks, Laurence D.

109

Metal on metal oxide nanowire Co-catalyzed Si photocathode for solar water splitting.  

PubMed

We report a systematic study of Si|ZnO and Si|ZnO| metal photocathodes for effective photoelectrochemical cells and hydrogen generation. Both ZnO nanocrystalline thin films and vertical nanowire arrays were studied. Si|ZnO electrodes showed increased cathodic photocurrents due to improved charge separation by the formation of a p/n junction, and Si|ZnO:Al (n(+)-ZnO) and Si|ZnO(N(2)) (thin films prepared in N(2)/Ar gas) lead to a further increase in cathodic photocurrents. Si|ZnONW (nanowire array) photocathodes dramatically increased the photocurrents and thus photoelectrochemical conversion efficiency due to the enhanced light absorption and enlarged surface area. The ZnO film thickness and ZnO nanowire length were important to the enhancements. A thin metal coating on ZnO showed increased photocurrent due to a catalyzed hydrogen evolution reaction and Ni metal showed comparable catalytic activities to those of Pt and Pd. Moreover, photoelectrochemical instability of Si|ZnO electrodes was minimized by metal co-catalysts. Our results indicate that the metal and ZnO on p-type Si serve as co-catalysts for photoelectrochemical water splitting, which can provide a possible low-cost and scalable method to fabricate high efficiency photocathodes for practical applications in clean solar energy harvesting. PMID:22539234

Sun, Ke; Madsen, Kristian; Andersen, Pål; Bao, Weining; Sun, Zhelin; Wang, Deli

2012-05-17

110

Prothèse totale de genou \\  

Microsoft Academic Search

Preserving the cruciate ligaments using a non constrained total knee arthroplasty presents the usual disadvantage of increasing stress and needs perfect rotational balance. The use of mobile meniscal bearings, which is the original feature of the NEW JERSEY prosthesis, gives a simple solution to those two problems. 100 NEW JERSEY total knee arthroplasties were reviewed after a two-year follow-up. Plateaux

B. Reignier

1993-01-01

111

Total Quality Leadership  

NASA Technical Reports Server (NTRS)

More than 750 NASA, government, contractor, and academic representatives attended the Seventh Annual NASA/Contractors Conference on Quality and Productivity. The panel presentations and Keynote speeches revolving around the theme of total quality leadership provided a solid base of understanding of the importance, benefits, and principles of total quality management (TQM). The presentations from the conference are summarized.

1991-01-01

112

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...

113

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- ...

114

Total synthesis of (+)-angelmarin.  

PubMed

An efficient 8-step enantioselective total synthesis of (+)-angelmarin, starting from commercially available umbelliferone, has been achieved. Key reactions include olefin cross-metathesis and a Shi epoxidation-cyclization sequence. PMID:19459593

Magolan, Jakob; Coster, Mark J

2009-07-17

115

Total Hip Replacement  

MedlinePLUS

... as running, jogging, jumping, or other high-impact sports. Realistic activities following total hip replacement include unlimited ... driving, hiking, biking, dancing, and other low-impact sports. With appropriate activity modi? cation, hip replacements can ...

116

Exposures Information Totals Calls  

E-print Network

Information Call Type Totals Calls 2010: 30,979 2011: 29,916 #12;0 500 1000 1500 2000 2500 3000 3500 1 2 3 4 5 Analgesics Sedative/hypnotics/antipsych Topical preparations Antidepressants Cardiovascular drugs

Oliver, Douglas L.

117

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.

2011-04-29

118

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.

119

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

E-print Network

.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 Ticket Total to the Purchase Totals section below. Subtotal $ INDIVIDUAL Ticket Total $ PURCHASE TOTALS

Roy, Subrata

120

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; King, John

2010-08-06

121

Total synthesis of jiadifenolide.  

PubMed

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

2014-07-01

122

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

123

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

124

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...

125

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...

126

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.

127

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

128

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 = ...

129

Product Description (<100) Total  

E-print Network

(Amex, MC, Visa) Contact Name Credit card number Expiration Date mm-yy Street Address, Suite # Name Credit card will be charged on shipment day Phone Number Fax Number E-mail, Website Signature of credit to the credit card / shipping account Total: Shipping Address Credit Card Payment Information Company Name Type

Berns, Hans-Gerd

130

Laparoscopic robotic total gastrectomy  

PubMed Central

Minimally invasive gastrectomy has become the standard of care in many centers in Asia but remains unpopular in Europe. The aim of this article is to present the technique of laparoscopic robot-assisted total gastrectomy. The presented case involved a 66-year-old female patient with an advanced gastric cancer on the lesser curvature of the stomach. The laparoscopic part of the procedure involved opening the lesser sac, mobilization of the greater curvature and transection of the duodenum. A robot was used for the D2 lymphadenectomy and creation of the anastomosis. In summary, we have found that during a total gastrectomy for advanced gastric cancer a successful oncological resection can be achieved using a minimally invasive approach. We have also found that by combining conventional laparoscopy with robotic assistance we could overcome the technical difficulties with regards to lymph node dissection and anastomosis.

Witkiewicz, Wojciech

2014-01-01

131

Total synthesis of mevashuntin.  

PubMed

The total synthesis of (±)-mevashuntin, a structurally unique naturally occurring pyrano-naphthoquinone-thiazolone, is described. The route is centered upon a late stage regioselective Diels-Alder reaction between two highly functionalized components, as well as an improved protocol for the one pot synthesis of benzothiazolones from ortho-bromoaryl isothiocyanates. The strategy results in a highly convergent route, providing access to the natural product in 11 steps from 3-(4-methoxyphenoxy)propanol and confirming its relative stereochemistry. PMID:22369640

Nawrat, Christopher C; Moody, Christopher J

2012-03-16

132

Total Reward Criteria  

Microsoft Academic Search

\\u000a This chapter deals with total reward criteria. We discuss the existence and structure of optimal and nearly optimal policies\\u000a and the convergence of value iteration algorithms under the so-called General Convergence Condition. This condition assumes\\u000a that, for any initial state and for any policy, the expected sum of positive parts of rewards is finite. Positive, negative,\\u000a and discounted dynamic programming

Eugene A. Feinberg

133

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

134

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

135

Comparison between 28 mm and 32 mm ceramic-on-ceramic bearings in total hip replacement.  

PubMed

Large femoral heads have become popular in total hip replacement (THR) as a method of reducing the risk of dislocation. However, if large heads are used in ceramic-on-ceramic THR, the liner must be thinner, which may increase the risk of fracture. To compare the rates of ceramic fracture and dislocation between 28 mm and 32 mm ceramic heads, 120 hips in 109 patients (51 men and 58 women, mean age 49.2 years) were randomised to THR with either a 28 mm or a 32 mm ceramic articulation. A total of 57/60 hips assigned to the 28 mm group and 55/60 hips assigned to the 32 mm group were followed for at least five years. No ceramic component fractures occured in any patient in either group. There was one dislocation in the 32 mm group and none in the 28 mm group (p = 0.464). No hip had detectable wear, focal osteolysis or prosthetic loosening. In our small study the 32 mm ceramic articulation appeared to be safe in terms of ceramic liner fracture. PMID:25371457

Lee, Y K; Ha, Y C; Koo, K H

2014-11-01

136

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

137

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

138

Total organic carbon analyzer  

NASA Technical Reports Server (NTRS)

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 TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

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

1991-01-01

139

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.

140

Total synthesis of taxol.  

PubMed

Taxol, a substance originally isolated from the Pacific yew tree (Taxus brevifolia) more than two decades ago, has recently been approved for the clinical treatment of cancer patients. Hailed as having provided one of the most significant advances in cancer therapy, this molecule exerts its anticancer activity by inhibiting mitosis through enhancement of the polymerization of tubulin and consequent stabilization of microtubules. The scarcity of taxol and the ecological impact of harvesting it have prompted extension searches for alternative sources including semisynthesis, cellular culture production and chemical synthesis. The latter has been attempted for almost two decades, but these attempts have been thwarted by the magnitude of the synthetic challenge. Here we report the total synthesis of taxol by a convergent strategy, which opens a chemical pathway for the production of both the natural product itself and a variety of designed taxoids. PMID:7906395

Nicolaou, K C; Yang, Z; Liu, J J; Ueno, H; Nantermet, P G; Guy, R K; Claiborne, C F; Renaud, J; Couladouros, E A; Paulvannan, K

1994-02-17

141

Total organic carbon analyzer  

NASA Astrophysics Data System (ADS)

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 TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

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

142

Total Energy CMR Production  

SciTech Connect

The following outlines the optimized pulsed laser deposition (PLD) procedure used to prepare Nd{sub 0.67}Sr{sub 0.33}MnO{sub 3} (NSMO) temperature sensors at Towson University (Prof. Rajeswari Kolagani) for the LCLS XTOD Total Energy Monitor. The samples have a sharp metal/insulator transition at T {approx} 200 K and are optimized for operation at T {approx} 180 K, where their sensitivity is the highest. These samples are epitaxial multilayer structures of Si/YSZ/CeO/NSMO, where these abbreviations are defined in table 1. In this heterostructure, YSZ serves as a buffer layer to prevent deleterious chemical reactions, and also serves to de-oxygenate the amorphous SiO{sub 2} surface layer to generate a crystalline template for epitaxy. CeO and BTO serve as template layers to minimize the effects of thermal and lattice mismatch strains, respectively. More details on the buffer and template layer scheme are included in the attached manuscript accepted for publication in Sensor Letters (G. Yong et al., 2008).

Friedrich, S; Kolagani, R M

2008-08-11

143

Total artificial heart.  

PubMed

End-stage heart failure represents a highly morbid condition for the patient with limited treatment options. From a surgical perspective, the treatment options for effective long-term survival are usually limited to heart transplantation, heart-lung transplantation or implantation of a destination mechanical circulatory support device. Assuming an advanced heart-failure patient is indeed deemed a candidate for transplantation, the patient is subject to shortages in donor organ availability and thus possible further decompensation and potential death while awaiting transplantation. Various extracorporeal and implantable ventricular-assist devices (VADs) may be able to provide temporary or long-term circulatory support for many end-stage heart-failure patients but mechanical circulatory support options for patients requiring long-term biventricular support remain limited. Implantation of a total artificial heart (TAH) currently represents one, if not the best, long-term surgical treatment option for patients requiring biventricular mechanical circulatory support as a bridge to transplant. The clinical applicability of available versions of positive displacement pumps is limited by their size and complications. Application of continuous-flow technology can help in solving some of these issues and is currently being applied in the research towards a new generation of smaller and more effective TAHs. In this review, we discuss the history of the TAH, its development and clinical application, implications for anaesthetic management, published outcomes and the future outlook for TAHs. PMID:22910087

Sale, Shiva M; Smedira, Nicholas G

2012-06-01

144

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

145

Refractometry by Total Reflection  

NASA Astrophysics Data System (ADS)

Refractometry is a means to measure the refractive indices of liquids, gases, and dielectric solids, either isotropic or anisotropic, by observation of light refraction of reflection with a microscope, refractometer or other more specialized equipment. For anisotropic solids, refractometry by total reflection (RTR) is by far the simplest, most rapid, and precise method to determine the refractive indices, provided a polished surface of sufficient size exists. Its precision exceeds that for routine oil immersion techniques but compares less favorably to that for minimum deviation methods. However, minimum deviation requires large crystals and, moreover, specifically oriented prisms, one for each principal refractive index to be measured and, for triclinic crystals, one for each wavelength of measurement. The phenomenon of polarized light reflection from randomly oriented anisotropic materials has been modeled because, only after a complete understanding of these phenomena could the RTR method be automated. The mathematics and physics required for this stem from theories and equations presented in the literature of ellipsometry, polarized light, and physical optics. These were then modified, rewritten, and unified to suit the requirements of RTR. RTR, first used by Wollaston (1802a, 1802b), was later perfected for the measurement of the refractive indices and orientation of biaxial minerals in thin section (Viola 1899a, 1899b, 1902; Cornu 1901, 1902). RTR with the Abbe -Pulfrich refractometer yielded refractive indices to a precision of +/-0.0002, or better. Later, Smith (1905a, 1905b) introduced a simpler refractometer, now known as the jeweler's refractometer, which had a precision of +/-0.001 to +/-0.002. This refractometer is still in use by gemologists. During this century familiarity with the early work has declined; thus several recent papers display a lack of knowledge of aspects of RTR which were already documented in the early 1900s. A new automated refractometer, designed by Bloss, has precision of +/-0.0002 and will be able to measure the refractive indices and orientation of a biaxial mineral in a petrographic thin section. Even for triclinic crystals, a single polished surface arbitrarily oriented will suffice for measurement of all three principal refractive indices, whatever the wavelength supplied. The design and testing of this refractometer has taken approximately three years. Two prototypes have been built and tested. Results from the second prototype are presented.

Gunter, Mickey E.

1987-09-01

146

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.

Administration, Energy I.

147

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

148

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

149

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

150

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

151

Effect of acetabular cup design on metal ion release in two designs of metal-on-metal hip resurfacing.  

PubMed

The purpose of this observational prospective cohort study was to evaluate the serum concentrations of cobalt (Co), chromium (Cr), and nickel (Ni) at a 2-year follow-up in patients operated on with a novel design of hip resurfacing: Romax resurfacing system (RRS). RRS is characterized by the presence of an acetabular notch which theoretically provides a wider range of motion and a reduced incidence of groin pain. The presence of radiolucencies and functional outcome, assessed using the Harris hip score (HHS) and the University of California Activity scale (UCLA), were secondary endpoints. Moreover, these results were compared with those obtained in our previous study from a similar cohort of patients implanted using the Birmingham Hip Resurfacing (BHR) system. At a 2-year follow-up, the serum levels of Co in patients operated on using the RRS were five times higher (p?=?0.0002) than those found before surgery (Co, means: 1.04 and 0.20 ng/mL, respectively); similarly, Cr levels were 13 times higher (p?

Cadossi, Matteo; Tedesco, Giuseppe; Savarino, Lucia; Baldini, Nicola; Mazzotti, Antonio; Greco, Michelina; Giannini, Sandro

2014-10-01

152

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

153

Total energy of metallic lithium  

Microsoft Academic Search

Procedures are presented for the accurate calculation of the total energy of a solid within the framework of the local-density approximation. The starting point is a self-consistent band calculation using a basis of localized orbitals. The method is applied to study the total energy of metallic lithium as a function of lattice spacing. Good results are obtained for the cohesive

J. Callaway; Xianwu Zou; D. Bagayoko

1983-01-01

154

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

155

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

156

MSU-Bozeman Total Faculty  

E-print Network

Total College % Women 10.6 College of Letters and Science 0 Cell Biology 191 Total College % Women 26.7 College of Nursing 3 8 6 1 18 100 89 100 94.4 Libaries 1 2 4 STEM departments Data as of November 2010 Table 1a. Number and Percent

Maxwell, Bruce D.

157

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

158

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.

Bank, World

159

Forgotten Aspects of Total Communication  

ERIC Educational Resources Information Center

Discussed are various aspects of the "total communication" concept of deaf education that have been neglected, including diagnosis, teacher certification, amplification, voice and sign, speechreading, speech teaching and development, and skill in sign language. (DLS)

Alexander, Kenneth R.

1978-01-01

160

Total patellar skin loss from cryotherapy after total knee arthroplasty.  

PubMed

The use of cryotherapy after total knee arthroplasty is a very common therapeutic adjunct accepted as routine postoperative care. We present 2 cases of total patellar skin loss due to cryotherapy after total knee arthroplasty. Substantial soft tissue defects were created after the initial debridement of the necrotic tissue. Both patients were evaluated for frostbite, and the wounds were sharply debrided. Application of an advanced wound management technique involves the use of a collagen-glycosaminoglycan biodegradable bilayer matrix, silver impregnated antimicrobial dressing, and low-pressure vacuum device, followed by delayed split thickness skin grafting and low-pressure vacuum device. We find that this technique provided durable soft tissue coverage for necrotic wounds of the knee that do not involve the joint capsule. PMID:22749659

Dundon, John M; Rymer, Michael C; Johnson, Ron M

2013-02-01

161

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

162

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

163

Totally Ossified Metaplastic Spinal Meningioma  

PubMed Central

A 61-year-old woman with a very rare case of totally ossified large thoracic spinal metaplastic meningioma, showing progressing myelopathy is presented. Computed tomographic images showed a large totally ossfied intradural round mass occupying the spinal canal on T9-10 level. Magnetic resonance imaging revealed a large T9-10 intradural extramedullary mass that was hypointense to spinal cord on T1- and T2-weighted sequences, partial enhancement was apparent after Gadolinium administration. The spinal cord was severely compressed and displaced toward the right at the level of T9-10. Surgical removal of the tumor was successfully accomplished via the posterior midline approach and the histological diagnosis verified an ossified metaplastic meningioma. The clinical neurological symptoms of patient were improved postoperatively. In this article we discuss the surgical and pathological aspects of rare case of spinal totally ossified metaplastic meningioma. PMID:24278660

Hida, Kazutoshi; Yamauchi, Tomohiro; Houkin, Kiyohiro

2013-01-01

164

Totally ossified metaplastic spinal meningioma.  

PubMed

A 61-year-old woman with a very rare case of totally ossified large thoracic spinal metaplastic meningioma, showing progressing myelopathy is presented. Computed tomographic images showed a large totally ossfied intradural round mass occupying the spinal canal on T9-10 level. Magnetic resonance imaging revealed a large T9-10 intradural extramedullary mass that was hypointense to spinal cord on T1- and T2-weighted sequences, partial enhancement was apparent after Gadolinium administration. The spinal cord was severely compressed and displaced toward the right at the level of T9-10. Surgical removal of the tumor was successfully accomplished via the posterior midline approach and the histological diagnosis verified an ossified metaplastic meningioma. The clinical neurological symptoms of patient were improved postoperatively. In this article we discuss the surgical and pathological aspects of rare case of spinal totally ossified metaplastic meningioma. PMID:24278660

Ju, Chang Il; Hida, Kazutoshi; Yamauchi, Tomohiro; Houkin, Kiyohiro

2013-09-01

165

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

166

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

167

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

168

[Total gastrectomy with substitute stomach].  

PubMed

A modified technique of jejunum-reservoir after total gastrectomie for gastric cancer is recommended. The advantages of this method are the simplicity of technique, the preservation of duodenal passage, the avoiding of reflux and the normal emptying time of reservoir. PMID:617131

Nadjafi, A S

1977-03-01

169

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

170

MUJERES TOTAL BIOLOGIA 14 28  

E-print Network

DESARROLLO 4 4 FINANCIACION E INVESTIGACION COMERCIAL 2 5 ORGANIZACION DE EMPRESAS 1 1 9 21 CIENCIA POLITICA 2013 CIENCIAS ECONÃ?MICAS Y EMPRESARIALES CIENCIAS #12;MUJERES TOTAL INTERFACULTATIVO DE PSICOLOGIA EVOLUTIVA Y DE LA EDUCACION 6 9 PSICOLOGIA BASICA 4 5 PSICOLOGIA BIOLOGICA Y DE LA SALUD 10 15 PSICOLOGIA

Autonoma de Madrid, Universidad

171

Endoscopic Transaxillary Near Total Thyroidectomy  

PubMed Central

Background: Since first reported in 1996, endoscopic minimally invasive surgery of the cervical region has been shown to be safe and effective in the treatment of benign thyroid and parathyroid disease. The endoscopic transaxillary technique uses a remote lateral approach to the thyroid gland. Because of the perceived difficulty in accessing the contralateral anatomy of the thyroid gland, this technique has typically been reserved for patients with unilateral disease. Objectives: The present study examines the safety and feasibility of the transaxillary technique in dissecting and assessment of both thyroid lobes in performing near total thyroidectomy. Methods: Prior to this study we successfully performed endoscopic transaxillary thyroid lobectomy in 32 patients between August 2003 and August 2005. Technical feasibility in performing total thyroidectomy using this approach was accomplished first utilizing a porcine model followed by three human cadaver models prior to proceeding to human surgery. After IRB approval three female patients with histories of enlarging multinodular goiter were selected to undergo endoscopic near total thyroidectomy. Results: The average operative time for all models was 142 minutes (range 57–327 min). The three patients in this study had clinically enlarging multinodular goiters with an average size of 4 cm. The contralateral recurrent laryngeal nerve and parathyroid glands were identified in all cases. There was no post-operative bleeding, hoarseness or subcutaneous emphysema. Conclusion: Endoscopic transaxillary near total thyroidectomy is feasible and can be performed safely in human patients with bilateral thyroid disease. PMID:16882421

Ejeh, Ijeoma Acholonu; Speights, Fredne; Rashid, Qammar N.; Ideis, Mustafa

2006-01-01

172

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

173

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

174

Total synthesis of lysergic acid.  

PubMed

A total synthesis of lysergic acid was accomplished. Key features of our synthesis include stereoselective construction of the stereogenic centers at the allylic positions by using the Evans aldol reaction, and a sequential process with a ring-closing metathesis and an intramolecular Heck reaction to construct the C and D rings. PMID:23919892

Umezaki, Satoshi; Yokoshima, Satoshi; Fukuyama, Tohru

2013-08-16

175

Total control worth by inspection  

Microsoft Academic Search

A simple calculational method is developed that can quickly and accurately estimate total control rod worth for a class of reactors possessing fuel\\/control channel symmetry throughout its core. The movable, nonfissionable, poisoned control channel has identical neutron absorption and scattering properties and geometry similar to the fuel channels. Hexagonal lattices employed in fast breeder and graphite-moderated thermal reactors possess the

Marotta

1987-01-01

176

Total system heat loss measurements  

Microsoft Academic Search

Excessive heat losses from insulated systems in service raise critical design questions when compared with performance data obtained from individual insulation specimens tested in the laboratory. The object of the present work was to verify analytical methods for predicting total system heat loss. These methods predicted that some heat loss components --in particular, free convective air flows--can be significant. Verification

B. A. Allmon; D. A. Rausch; H. W. Wahle

1981-01-01

177

Total system heat loss measurements  

Microsoft Academic Search

Excessive heat losses from insulated systems in service raise critical design questions when compared with performance data obtained from individual insulation specimens tested in the laboratory. In many cases, excessive heat loss is caused by the incorrect design assumption that total system heat loss is equal only to that through individual insulation sections. However, additional heat losses result from the

B. A. Allmon; D. A. Rausch; H. W. Wahle

1983-01-01

178

A simple total energy sensor  

NASA Technical Reports Server (NTRS)

This research concerns a simple technique for total energy compensation having the primary requirement of good compensation with a low cost, easy to make sensor. A comprehensive library search and a small wind tunnel were used to explore fundamentals and to develop a number of probes which were flight tested with satisfactory results. Simple probe configurations were tested using the characteristics of laminar flow separation around a small cylinder to produce a sensor pressure having the desired relationship between static and dynamic pressures. Wind tunnel and flight tests confirmed the concepts for a wide range of speeds, altitudes, and flow directions encountered in soaring. Data and findings are presented, along with a discussion of factors important to total energy compensation.

Nicks, O. W.

1976-01-01

179

Total Synthesis of Apoptolidin A  

PubMed Central

A highly convergent, enantioselective total synthesis of the potent antitumor agent apoptolidin A, has been completed. The key transformations include highly selective glycosylations to attach the C27 disaccharide and the C9 6?-deoxy-l-glucose, a cross metathesis to incorporate the C1-C10 trienoate unit, and a Yamaguchi macrolactonization to complete the macrocycle. Twelve stereocenters in the polypropionate segments and sugar units were established through diastereoselective chlorotitanium enolate aldol reactions. PMID:19199767

Crimmins, Michael T.; Christie, Hamish S.; Long, Alan; Chaudhary, Kleem

2009-01-01

180

Total thyroidectomy: Complications and technique  

Microsoft Academic Search

During the 27-year period from 1957 to 1984, four hundred thirty patients underwent total thyroidectomies for malignant or benign disease of the thyroid gland at our institutions. Thyroid cancer was found in 83.4% of cases, and 47.2% of these had concomitant lymph node dissections. Transient recurrent laryngeal nerve injury occurred in 6.2% of the entire series. Permanent unilateral vocal cord

Jay K. Harness; Lit Fung; Norman W. Thompson; Richard E. Burney; Michael K. McLeod

1986-01-01

181

Dislocation after total hip arthroplasty  

Microsoft Academic Search

Hip dislocation has long been one of the major complications after total hip arthroplasty (THA). From 1980 to 1994, we performed\\u000a 2728 THAs (including primary and revision cases). There were 97 hips (3.6%) with the complication of dislocation, 62 of which\\u000a were followed up for at least 2 years (mean 5.3 years; range 2–12 years). Single dislocations occurred in 40%

L.-J. Yuan; C.-H. Shih

1999-01-01

182

Total synthesis of (+/-)-pentacycloanammoxic acid.  

PubMed

The first total synthesis of (+/-)-pentacycloanammoxic acid/methyl ester (1), an unusual naturally occurring fatty acid from Candidatus Brocadia anammoxidans, has been accomplished by the sequence of reactions shown in Scheme 1. The C20-structure of 1 was assembled with stereocontrol from three building blocks: cyclooctatetraene, 2-cyclopentenone, and 7-bromoheptanoic acid. The synthesis of 1 confirms the proposed structure of 1. The mode of biosynthesis and absolute configuration have yet to be clarified. PMID:15571387

Mascitti, Vincent; Corey, E J

2004-12-01

183

Total synthesis of (+)-cylindradine A.  

PubMed

Cylindradines A and B, members of the polycyclic pyrrole-imidazole alkaloids (PIAs), are the only congeners bearing a 3-carbamoylpyrrole unit among the PIAs. In this communication, we described a total synthesis of (+)-cylindradine A based on intramolecular Friedel-Crafts type cyclization of pyrrole-aldehyde and oxidative cyclization of tricyclic pyrrolopyrrolidine-guanidine with hypervalent iodine to construct the cyclic guanidine structure including the N,N'-aminal moiety. PMID:24846327

Iwata, Makoto; Kanoh, Kyohei; Imaoka, Takuya; Nagasawa, Kazuo

2014-07-01

184

Total Synthesis of (+)-Isatisine A  

PubMed Central

Total synthesis of (+)-isatisine A is described based on the application of a silyl-directed Mukaiyama-type [3+2]-annulation for the preparation of a fully substituted furan core. The indole branch forming the quaternary carbon center at C2 was constructed by addition to an intermediate N-acyliminium ion derived from aminal 4. In addition, the fused tetracyclic framework including furan core was built up using modified Buchwald amidation conditions. PMID:21188973

Lee, Jihoon; Panek, James S.

2011-01-01

185

Osteopetrosis and total hip arthroplasty  

Microsoft Academic Search

Summary. Two patients with osteopetrosis and osteoarthrosis of the hip underwent “hybrid” total hip replacement. There are technical\\u000a difficulties in seating acetabular and femoral components on hard and brittle osteopetrotic bone with an obliterated marrow\\u000a cavity. Although the surgical procedures are challenging, this form of arthroplasty is recommended for hip osteoarthrosis\\u000a which is associated with osteopetrosis.\\u000a   

T. Matsuno; N. Katayama

1998-01-01

186

Characterization of total flare energy  

NASA Technical Reports Server (NTRS)

It is concluded that the estimates of total energy in the prime flares lie well below the Active Cavity Radiometer Irradiance Monitor upper limits. This is consistent with our knowledge of the energy distribution in solar flares. Insufficient data exist for us to be very firm about this conclusion, however, and major energetic components could exist undetected, especially in the EUV-XUV and optical bands. In addition, the radiant energy cannot quantitatively be compared at this time with non-radiant terms because of even larger uncertainties in the latter.

Hudson, H. S.

1986-01-01

187

Total Synthesis of 7?-Desmethylkealiiquinone  

PubMed Central

The total synthesis of an analog of the marine alkaloid kealiiquinone has been completed through application of an intramolecular Diels-Alder reaction of an imidazole-containing enyne. Oxidative aromatization of the lactone adduct and N-methylation facilitates C2-oxidation via the imidazolium salt. Conversion of the lactone to the phthalaldehyde derivative and then to the dihydroxybenzoquinone was achieved via a reaction with glyoxal in the presence of KCN. Esterification of the vinylogous diacid and deprotection provided 7?-desmethylkealiiquinone. PMID:22530654

Lima, Heather M.; Sivappa, Rasapalli; Yousufuddin, Muhammed; Lovely, Carl J.

2012-01-01

188

Total synthesis of (±)-antroquinonol d.  

PubMed

Total synthesis of (±)-antroquinonol D, which is isolated from very expensive and rarely found Antrodia camphorata and which has potential anticancer properties, was achieved from 4-methoxyphenol. In addition, a Michael addition to dimethoxy cyclohexadienones was studied. The main step involved chelation and substrate-controlled diastereoselective reduction of cyclohexenone and lactonization. Lactone synthesis facilitated the diastereoselective reduction of ketone, which help control the desired stereochemistry at the crucial stereogenic center in the natural product. Other key reactions in the synthesis involved a Michael addition of dimethyl malonate on cyclohexadienone, dihydroxylation, and Wittig olefination. A sesquiterpene side chain was synthesized through coupling with geranyl phenyl sulfide and Bouveault-Blanc reduction. PMID:25375772

Sulake, Rohidas S; Jiang, Yan-Feng; Lin, Hsiao-Han; Chen, Chinpiao

2014-11-21

189

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

190

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

191

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

192

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

193

Total extraperitoneal endoscopic hernioplasty (TEP).  

PubMed

One can no longer think about modern hernia surgery without mentioning endoscopic techniques. But due to their high technical demands the learning curve is comparatively long. And by technical mistakes and their consequences (pain, recurrence, complications) the benefits of the endoscopic techniques can easily be turned to drawbacks. The following text explains the steps of the total extraperitoneal endoscopic hernioplasty (TEP) technique in detail pointing out alternatives and risks. From preparation, indication and positioning, from trocar placement to extraperitoneal dissection and mesh placement, the principles of TEP are elucidated in respect of local anatomy and possible complications. The text as well as the accompanying video in the Mediathek are based on the authors' 20 years of experience in the TEP technique. Both of them may help in safe TEP application to minimise the complication rate as well as recurrences. Then patients can benefit from the advantages of this technique. PMID:24777598

Kuthe, A; Mainik, F; Flade-Kuthe, R

2014-04-01

194

Total synthesis of (+)-lysergic acid.  

PubMed

We report the enantioselective total synthesis of (+)-lysergic acid using two different strategies, which featured three metal-catalyzed reactions for the construction of the BCD three rings, involving Pd-catalyzed indole synthesis for the construction of the B ring, a ring-closing metathesis reaction for the formation of the D ring, and an intramolecular Heck reaction to forge the C ring. In synthetic strategy I, the synthesis was achieved in 20 steps following the ring construction sequence of BDC. In synthetic strategy II, the synthetic route was shortened to only 12 steps by following the ring construction sequence of DBC and using a 4-chlorotryptophan derivative for the intramolecular Heck reaction. Moreover, we also discussed an unsuccessful synthetic strategy. PMID:24111583

Liu, Qiang; Zhang, Yu-An; Xu, Ping; Jia, Yanxing

2013-11-01

195

Total Maximum Daily Load Program  

NSDL National Science Digital Library

The Environmental Protection Agency (EPA) provides this informative resource on Total Maximum Daily Loads (TMDL). A term used to discuss water quality, TMDL refers to "a calculation of the maximum amount of a pollutant that a water body can receive and still meet water quality standards." The TMDL Program Website offers background information on TMDLs (including FAQs), a National Overview of Impaired Waters in the US, and two standard presentations on TMDLs (HTML and Power Point). The heart of the site, however, is the interactive map of the US, which allows users access to each state's TMDL Program. Within each state, watershed names and maps, as well as source information (Water body, Parameter of Concern, Priority for TMDL Development), are provided.

196

Total Petroleum Hydrocarbons (TPH): ToxFAQs  

MedlinePLUS

... a state: This map displays locations where Total Petroleum Hydrocarbons (TPH) is known to be present. On ... I get more information? ToxFAQs TM for Total Petroleum Hydrocarbons (TPH) ( Hidrocarburos Totales de Petróleo (TPH) ) August ...

197

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

198

Deformation of the Durom Acetabular Component and Its Impact on Tribology in a Cadaveric Model—A Simulator Study  

PubMed Central

Background Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM) total hips in simulators. Methods Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC) wear test in simulators. Results The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78±8.86 µm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65±0.29 mm3/MC and 0.89±0.04 mm3/MC (t?=?48.43, p?=?0.000). The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. Conclusions This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. Clinical Relevance This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care. PMID:23144694

Gu, Yanqing; Wang, Qing; Cui, Weiding; Fan, Weimin

2012-01-01

199

Total hydrocarbon analyzer evaluation study  

SciTech Connect

Measuring and controlling organic emissions from incineration processes has become a major environmental concern in recent years. The US Environmental Protection Agency (EPA) recently proposed a regulation for sewage sludge incinerators under section 405(d) of the Clean Water Act that will require all sludge incinerators to monitor total hydrocarbon emissions (THCs) on a continuous basis. Such a requirement would be part of National Pollutant Discharge Elimination (NPDES) permits and site-specific THC limits would be established for facilities based on a risk assessment of organic emissions. Before EPA can finalize the proposed requirement, THC monitoring must be successfully conducted in a plant environment and the system required by any final regulation must be kept in operation so that facilities can comply with their permits. The Metropolitan Waste Control Commission (MWCC) in St. Paul, Minn., and Rosemount Analytical Division in La Habre, Calif., entered into a joint agreement with EPA to demonstrate a hot' THC monitoring system to detect THCs in stack gases. The objectives of the study are to determine the feasibility of THC monitoring of sludge incinerator emissions; evaluate the long term reliability, cost of operation, and consistency of a continuous THC monitoring system in an incinerator environment; and determine the correlation of THC stack concentration to incinerator and scrubber operating conditions, carbon monoxide concentration, and specific VOC emissions.

Shamat, N. (EMA Services, Inc., St. Paul, MN (United States)); Crumpler, E. (Environmental Protection Agency, Washington, DC (United States)); Roddan, A. (Rosemount Analytical Division, La Habra, CA (United States))

1991-10-01

200

COURSE OR OR CR. Total Crs.: 4  

E-print Network

208 3 CHEM 209 2 14 NFSC 280 1 NFSC 296 1 NFSC 299 2 Total Crs.: 4 MATH 204 3 CMPS 209 3 EDUC 227 STAT, 214, 215, 216, 217, AND 218 ARE EXCLUDED. Total Crs.: Total Crs.: REQUIRED SUMMER TRAINING & SEMINAR OR EQUIVALENTa CRS.: DIPLOMA TYPE : ENTRY LEVEL : FR SO JR SR COMMENTS Total Credits in Major: f MUST BE CHOSEN

Shihadeh, Alan

201

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

202

OFFICIAL VEHICLE AND VENDOR STALLS Total Vendor  

E-print Network

OFFICIAL VEHICLE AND VENDOR STALLS Location Total OV Stalls Total Vendor Stalls Combo Stalls Total Stalls in Area EAST BANK Between Pattee and Shevlin 3 0 0 3 N. of Burton Hall on Pillsbury Drive 3 0 1 4/space quantity subject to change at any time. (page 1 of 2) #12;OFFICIAL VEHICLE AND VENDOR STALLS Location Total

Minnesota, University of

203

Complex primary total hip arthroplasty.  

PubMed

Although total hip arthroplasty is now a classic procedure that is well controlled by orthopedic surgeons, some cases remain complex. Difficulties may be due to co-morbidities: obesity, skin problems, muscular problems, a history of neurological disease or associated morphological bone deformities. Obese patients must be informed of their specific risks and a surgical approach must be used that obtains maximum exposure. Healing of incisions is not a particular problem, but adhesions must be assessed. Neurological diseases may require tenotomy and the use of implants that limit instability. Specific techniques or implants are necessary to respect hip biomechanics (offset, neck-shaft angle) in case of a large lever arm or coxa vara. In case of arthrodesis, before THA can be performed, the risk of infection must be specifically evaluated if the etiology is infection, and the strength of the gluteal muscles must be determined. Congenital hip dysplasia presents three problems: the position and coverage of the cup, placement of a specific or custom made femoral stem, with an osteotomy if necessary, and finally lowering the femoral head into the cup by freeing the soft tissues or a shortening osteotomy. Acetabular dysplasia should not be underestimated in the presence of significant bone defect (BD), and reconstruction with a bone graft can be proposed. Sequelae from acetabular fractures presents a problem of associated BD. Internal fixation hardware is rarely an obstacle but the surgical approach should take this into account. Treatment of acetabular protrusio should restore a normal center of rotation, and prevent recurrent progressive protrusion. The use of bone grafts and reinforcement rings are indispensible. Femoral deformities may be congenital or secondary to trauma or osteotomy. They must be evaluated to restore hip biomechanics that are as close to normal as possible. Fixation of implants should restore anteversion, length and the lever arm. Most problems that can make THA a difficult procedure may be anticipated with proper understanding of the case and thorough preoperative planning. PMID:23375960

Boisgard, S; Descamps, S; Bouillet, B

2013-02-01

204

The influence of the oscillation angle and the neck anteversion of the prosthesis on the cup safe-zone that fulfills the criteria for range of motion in total hip replacements. The required oscillation angle for an acceptable cup safe-zone.  

PubMed

A normal hip joint has more than 120 degrees flexion. The reduced range of motion (ROM) of total hip arthroplast leads to frequent prosthetic impingement, subluxation and dislocation. Prosthetic impingement may be more serious for metal-on-metal and ceramic-on-ceramic total hip prosthesis (THP). A larger oscillation angle of THP (OsA) and proper cup and neck positions make a larger theoretical ROM of a patient's artificial hip joint. But what OsA is required and what range of cup positions is kinetically accepted are not clearly understood. A ROM of more than 120 degrees flexion, 45 degrees internal-rotation at 90 degrees flexion, 30 degrees extension and 40 degrees external-rotation was defined as severe criteria for an acceptable ROM. Theoretical cup safe-zones were created that fulfill the severe criteria of ROM for (OsA=110 degrees , 120 degrees , 135 degrees ) by the mathematical formulas. The size of the cup safe-zone mainly depends on the size of the OsA. There is no cup safe-zone for 110 degrees OsA, an extremely small safe-zone for 120 degrees OsA and an acceptable safe-zone for 135 degrees OsA. Each THP has its own OsA, because OsA is the function of head and neck diameter and cup design. More than 135 degrees OsA enlarges the safe-zone of the prosthetic position, so it extends the acceptable range of error that surgeons cannot avoid completely. However, few THPs with more than 135 degrees OsA are currently clinically available. Both surgeons and manufacturers must realize that OsA is as essential as cup and neck orientations for ROM. PMID:15519347

Yoshimine, Fumihiro

2005-01-01

205

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

206

Benthic respiration measured by total carbonate production  

Microsoft Academic Search

Abstract The suitability of total carbonate production,instead of oxygen consumption,as a measure,of benthic respiration has been investigated. In situ fluxes of total carbonate, oxygen, calcium, total alkalinity, nutrients, and sulfide across the sediment-water interface were measured in diver- operated benthic flux chambers. Two chambers,were run in parallel to test the influence of oxygen and pH levels on total carbonate production.

LEIF G. ANDERSON; PER O. J. HALL; ÅKE IVERFELDT; MICHIEL M. RUTGERS VAN DER LOEFF; BJØRN SUNDBY; STIG F. G. WESTERLUND

1986-01-01

207

COURSE OR OR CR. Total Crs.: 4  

E-print Network

208 3 CHEM 209 2 14 NFSC 280 1 NFSC 296 1 NFSC 299 2 Total Crs.: 4 MATH 204 3 PROGRAM OF STUDY FRESHMAN CLASS OR EQUIVALENTa CRS.: DIPLOMA TYPE : ENTRY LEVEL : FR SO JR SR COMMENTS Total Credits in Major: Total Crs.: REQUIRED SUMMER TRAINING & SEMINAR COURSES REQUIRED SCIENCE COURSES REQUIRED MATH

Shihadeh, Alan

208

COURSE OR OR CR. Total Crs.: 4  

E-print Network

208 3 CHEM 209 2 14 NFSC 280 1 NFSC 296 1 NFSC 299 2 Total Crs.: 4 MATH 204 3 CMPS 209 3 EDUC 227 STAT CREDITS NEEDED FOR GRADUATION Total Crs.: FACULTY GENERAL REQUIREMENTS Total Crs.: NAME: Tel #: ID #: E-mail: @aub.edu.lb MAJOR REQUIRMENTS FRESHMAN CLASS OR EQUIVALENTa CRS.: DIPLOMA TYPE : ENTRY LEVEL : FR SO JR

Shihadeh, Alan

209

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.

210

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

211

6, 39133943, 2006 Svalbard total ozone  

E-print Network

ACPD 6, 3913­3943, 2006 Svalbard total ozone C. Vogler et al. Title Page Abstract Introduction Discussions Re-evaluation of the 1950­1962 total ozone record from Longyearbyen, Svalbard C. Vogler 1 , S. Br total ozone C. Vogler et al. Title Page Abstract Introduction Conclusions References Tables Figures Back

Boyer, Edmond

212

8, 31433162, 2008 Total ozone over  

E-print Network

ACPD 8, 3143­3162, 2008 Total ozone over oceanic regions M. C. R. Kalapureddy et al. Title Page Chemistry and Physics Discussions Total column ozone variations over oceanic region around Indian sub­3162, 2008 Total ozone over oceanic regions M. C. R. Kalapureddy et al. Title Page Abstract Introduction

Paris-Sud XI, Université de

213

5, 1133111375, 2005 NH total ozone  

E-print Network

ACPD 5, 11331­11375, 2005 NH total ozone increase S. Dhomse et al. Title Page Abstract Introduction On the possible causes of recent increases in NH total ozone from a statistical analysis of satellite data from License. 11331 #12;ACPD 5, 11331­11375, 2005 NH total ozone increase S. Dhomse et al. Title Page Abstract

Paris-Sud XI, Université de

214

Total Rewards At Washington and Lee  

E-print Network

Total Rewards At Washington and Lee March 15, 2013 University Facilities Work-Life Roundtable #12; Total Rewards Base Pay Benefits Performance and Career Development Recognition Work-Life 2 Our By Total Rewards? #12; W&L jobs are benchmarked against published salary surveys (CUPA-HR, APPA) Each

Marsh, David

215

Defense meteorological satellite measurements of total ozone  

NASA Technical Reports Server (NTRS)

A multichannel filter radiometer (MFR) on Defense Meteorological Satellites (DMS) that measured total ozone on a global-scale from March 1977 - February 1980 is described. The total ozone data measured by the MFR were compared with total ozone data taken by surfaced-based Dobson spectrophotometers. When comparisons were made for five months, the Dobson spectrophotometer measured 2-5% more total ozone than the MFR. Comparisons between the Dobson spectrophotometer and the MFR showed a reduced RMS difference as the comparisons were made at closer proximity. A Northern Hemisphere total ozone distribution obtained from MFR data is presented.

Lovill, J. E.; Ellis, J. S.; Luther, F. M.; Sullivan, T. J.; Weichel, R. L.

1982-01-01

216

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

217

IPEDS SUMMARY (EEO-6) REPORT AS OF NOVEMBER 1, 2008 F F Total P P Total Grand Total  

E-print Network

IPEDS SUMMARY (EEO-6) REPORT AS OF NOVEMBER 1, 2008 F F Total P P Total Grand Total IPEDS IPEDS 3,626 3,626 3,626 DRBN 35 35 35 FLNT 43 43 43 UMH 1,071 1,071 1,071 Inst/Res Asst ** Total 4,775 4,775 4,775 4 Other Prof AA 6,287 6,287 824 824 7,111 DRBN 165 165 35 35 200 FLNT 177 177 28 28 205 UMH 3

Awtar, Shorya

218

COURSE OR OR CR. Total Crs.: 4  

E-print Network

208 3 CHEM 209 2 14 NFSC 280 1 NFSC 296 1 NFSC 299 2 Total Crs.: 4 MATH 204 3 CMPS 209 3 EDUC 227 STAT (INCLUDING c ARABIC 213, 214, 215, 216, 217, AND 218 ARE EXCLUDED. Total Crs.: Total Crs.: REQUIRED SUMMER-mail: @aub.edu.lb MAJOR REQUIRMENTS FRESHMAN CLASS OR EQUIVALENT a CRS.: DIPLOMA TYPE : ENTRY LEVEL : FR SO

Shihadeh, Alan

219

Sports Activity After Total Hip Resurfacing  

Microsoft Academic Search

Background: Little is known about sports activity after total hip resurfacing.Hypothesis: Patients undergoing total hip resurfacing can have a high level of sports activity.Study Design: Case series; Level of evidence, 4.Methods: The authors evaluated the level of sports activities with a standardized questionnaire in 138 consecutive patients (152 hips) 2 years after total hip resurfacing. Range of motion, Harris hip

Marc Banerjee; Bertil Bouillon; Carolin Banerjee; Holger Bäthis; Rolf Lefering; Miriam Nardini; Joachim Schmidt

2010-01-01

220

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

221

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

222

Formal total synthesis of cyanolide A.  

PubMed

Formal total synthesis of cyanolide A, aglycosidic dimeric macrolide is accomplished. The key reactions involved are asymmetric acetate aldol reaction, CBS reduction, and Shiina's lactonization. PMID:21280592

Pabbaraja, Srihari; Satyanarayana, K; Ganganna, B; Yadav, J S

2011-03-18

223

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

224

Total recall for Ajax applications CS298 Report Total Recall for AJAX applications Firefox extension  

E-print Network

Total recall for Ajax applications CS298 Report Total Recall for AJAX applications ­ Firefox Smita Periyapatna 1 05/15/2009 #12;Total recall for Ajax applications CS298 Report © 2009 Smita Periyapatna Smita Periyapatna 2 05/15/2009 #12;Total recall for Ajax applications CS298 Report APPROVED

Pollett, Chris

225

COURSE OR OR CR. Total Crs.: 4  

E-print Network

208 3 CHEM 209 2 14 NFSC 280 1 NFSC 296 1 NFSC 299 2 Total Crs.: 4 MATH 204 3 CMPS 209 3 EDUC 227 STAT, AND 218 ARE EXCLUDED. Total Crs.: REQUIRED ECONOMIC AND SOCIAL SCEINCE COURSES REQUIRED SCIENCE COURSES d SCIENCE COURSES FRESHMAN CLASS OR EQUIVALENTa CRS.: DIPLOMA TYPE : ENTRY LEVEL : FR SO JR SR COMMENTS

Shihadeh, Alan

226

Educating Deaf Children: The Total Approach.  

ERIC Educational Resources Information Center

The use of total communication in educating deaf preschool and elementary school students in the Santa Ana Program for the Hearing Impaired, Orange County, California, is described. Total communication is explained to consist of auditory training, speech, speechreading, fingerspelling, and the language of signs. Aspects of the program described…

Santa Ana Unified School District, CA.

227

Total recall: are privacy changes inevitable?  

Microsoft Academic Search

Total Recall is a system that records an individual perspective of the world using personal sensors such as a microphone in a pair of glasses or a camera in a necklace. There are many applications of Total Recall -- patients accurately recording what they've recently eaten, students replaying any part of a class, and so on--that can significantly improve people's

William C. Cheng; Leana Golubchik; David G. Kay

2004-01-01

228

Approximating total flow time on parallel machines  

Microsoft Academic Search

We consider the problem of optimizing the total flow timeof a stream of jobs that are released over time in a multiprocessorsetting. This problem is NP-hard even when weallow preemption, and have only two machines. Althoughthe total (or average) flow time is widely accepted as a goodmeasurement of the overall quality of service, no approximationalgorithms were known for this basic

Stefano Leonardi; Danny Raz

1997-01-01

229

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

230

Antibiotic prophylaxis in total hip arthroplasty  

Microsoft Academic Search

We have assessed the effect of different regimes of antibiotic prophylaxis on the survival of total hip implants, comparing antibiotics administered both systemically and in the bone cement, systemically only, in the bone cement only and with no antibiotics given. We studied 10 905 primary cemented total hip replacements, performed for osteoarthritis of the hip and reported to the Norwegian

B. Espehaug; L. B. Engesaeter; S. E. Vollset; L. I. Havelin; N. Langeland

1997-01-01

231

TOTAL ECLIPSE EXPEDITION AUSTRALIA NOVEMBER 2012  

E-print Network

TOTAL ECLIPSE EXPEDITION AUSTRALIA NOVEMBER 2012 November 14th next year, will see the most accessible Total Solar Eclipse until August 2017. We at Ulster travel are hoping that you will not want of Cairns. This eclipse being one of the few that crosses an international airport, will be extremely

232

Total Quality Management: the ASD experience  

Microsoft Academic Search

The author summarizes the evolution and operation of TQM (total-quality management) at ASD (Aeronautical Systems Division, Wright-patterson AFB) and discusses the lessons being learned. The discussion includes a short history of how ASD became involved in TQM, a description of the structure, an outline of the duties of the Assistant to the Commander for Total Quality Management, whose job is

R. S. Alexander

1989-01-01

233

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...

234

A total quality management methodology for universities  

Microsoft Academic Search

This research document is motivated by the need for a systemic, efficient quality improvement methodology at universities. There exists no methodology designed for a total quality management (TQM) program in a university. The main objective of this study is to develop a TQM Methodology that enables a university to efficiently develop an integral total quality improvement (TQM) Plan. ^ Current

Jose Carlos Flores-Molina

2011-01-01

235

Total solar irradiance during the Holocene  

Microsoft Academic Search

For the first time a record of total solar irradiance covering 9300 years is presented, which covers almost the entire Holocene. This reconstruction is based on a recently observationally derived relationship between total solar irradiance and the open solar magnetic field. Here we show that the open solar magnetic field can be obtained from the cosmogenic radionuclide 10Be measured in

F. Steinhilber; J. Beer; C. Fröhlich

2009-01-01

236

DENSITY ESTIMATION BY TOTAL VARIATION REGULARIZATION  

E-print Network

DENSITY ESTIMATION BY TOTAL VARIATION REGULARIZATION ROGER KOENKER AND IVAN MIZERA Abstract. L1 based on total variation of the estimated density, its square root, and its logarithm ­ and their derivatives ­ in the context of univariate and bivariate density estimation, and compare the results to some

Mizera, Ivan

237

Macrolide Synthesis Total Synthesis of Phorboxazole A**  

E-print Network

Macrolide Synthesis Total Synthesis of Phorboxazole A** David R. Williams,* Andre A. Kiryanov­f] leading to a convergent, enantiocontrolled total synthesis of 1. [*] Prof. D. R. Williams, Dr. A. A A and 1 H NMR spectra of natural and synthetic material. We also thank Prof. Amos B. Smith for 1 H NMR

Williams, David R.

238

Total-pressure measurement in pulsating flows  

NASA Technical Reports Server (NTRS)

Pneumatic-type probe was used as comparison instrument with total pressure tubes to determine true average pressure and, thus, to determine if nonlinear averaging effects were significant. Since pneumatic probe is more complicated to use than a total-pressure tube, it is used only as a comparison instrument to determine extent of averaging effects.

Krause, L. N.; Dudzinski, T. J.; Johnson, R. C.

1973-01-01

239

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

240

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

241

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

242

Total lymphoid irradiation in alloimmunity and autoimmunity  

SciTech Connect

Total lymphoid irradiation has been used as an immunosuppressive regimen in autoimmune disease and organ transplantation. The rationale for its use originated from studies of patients with Hodgkin disease, in whom this radiotherapy regimen was noted to induce profound and long-lasting immune suppression and yet was well tolerated, with few long-term side effects. Total lymphoid irradiation is a unique immunosuppressive regimen that produces a selective (and long-lasting) reduction in the number and function of helper T cells and certain subsets of B cells. Conventional immunosuppressive drugs show little selectivity, and their effects are short-lived. The most important aspect of total lymphoid irradiation is the potential for achieving transplantation tolerance and permanent remissions in autoimmune disease in laboratory animals. Attempts are being made to achieve similar goals in humans given total lymphoid irradiation, so that immunosuppressive drugs can be ultimately withdrawn from transplant recipients and patients with lupus nephritis. 28 references.

Strober, S.

1987-12-01

243

Patient Matched Instruments and Total Knee System  

MedlinePLUS Videos and Cool Tools

Smith & Nephew Technologies: VISIONAIRE™ Patient Matched Instruments and LEGION™ Total Knee System You must have Javascript enabled in your web browser. View Program Transcript Click Here to view the OR-Live, Inc. Privacy Policy and Legal ...

244

Total Electric Schools From Elementary to University  

ERIC Educational Resources Information Center

Efficiency, lower operating costs, and flexibility are only a few of the reasons why total-electric facilities encompass the range of education from elementary schools to university buildings. (Author)

Modern Schools, 1975

1975-01-01

245

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

246

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

247

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

248

Safety Precautions for Total Release Foggers  

MedlinePLUS Videos and Cool Tools

Total release foggers, also known as "bug bombs," are pesticide products containing aerosol propellants that release their contents at once to fumigate an area. These products are often used around the ...

249

A concise total synthesis of (+/-)-anthecularin.  

PubMed

A total synthesis of the novel sesquiterpene anthecularin 1, isolated from Greek Anthemis auriculata, based on an intramolecular [5+2] (1,3-dipolar) cycloaddition involving the oxidopyrylium ion 12 derived from the furanmethanol 9, is described. PMID:19194574

Li, Yi; Nawrat, Christopher C; Pattenden, Gerald; Winne, Johan M

2009-02-21

250

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...

251

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

252

Total Synthesis of (–)- and ent-(+)-Vindoline  

PubMed Central

Two exceptionally concise total syntheses of (–)- and ent-(+)-vindoline are detailed enlisting a diastereoselective tandem [4+2]/[3+2] cycloaddition of a 1,3,4-oxadiazole. The unique reaction cascade assembles the fully functionalized pentacyclic ring system of vindoline in a single step that forms four C–C bonds and three rings while introducing all the requisite functionality and setting all six stereocenters within the central ring including three contiguous and four total quaternary centers. PMID:16178578

Choi, Younggi; Ishikawa, Hayato; Velcicky, Juraj; Elliott, Gregory I.; Miller, Michael M.; Boger, Dale L.

2008-01-01

253

Total PCBs in Liverpool Bay sediments  

Microsoft Academic Search

The concentrations of 55 congeners of PCBs were determined in < 500 ?m particles of 66 superficial sediment samples from Liverpool Bay. Total PCBs were significantly (p < 0.001) correlated with the amount of fine particles (r2 = 0.81) and with the organic carbon content (r2 = 0.80). The mean, maximum and minimum total PCB values were 3938, 37,880 and

V. F. Camacho-Ibar; J. McEvoy

1996-01-01

254

Beyond totally reflexive modules and back  

Microsoft Academic Search

\\u000a Starting from the notion of totally reflexive modules, we survey the theory of Gorenstein homological dimensions for modules\\u000a over commutative rings. The account includes the theory’s connections with relative homological algebra and with studies of\\u000a local ring homomorphisms. It ends close to the starting point: with a characterization of Gorenstein rings in terms of total\\u000a acyclicity of complexes.

Lars Winther Christensen; Hans-Bjørn Foxby; Henrik Holm

2008-01-01

255

A Total Quality Management Methodology for Universities  

Microsoft Academic Search

This research document is motivated by the need for a systemic, efficient quality improvement methodology at universities. There exists no methodology designed for a total quality management (TQM) program in a university. The main objective of this study is to develop a TQM Methodology that enables a university to efficiently develop an integral total quality improvement (TQM) Plan.\\u000aCurrent research

Jose C Flores-Molina

2011-01-01

256

Independent predictors of failure up to 7.5 years after 35 386 single-brand cementless total hip replacements: a retrospective cohort study using National Joint Registry data.  

PubMed

The popularity of cementless total hip replacement (THR) has surpassed cemented THR in England and Wales. This retrospective cohort study records survival time to revision following primary cementless THR with the most common combination (accounting for almost a third of all cementless THRs), and explores risk factors independently associated with failure, using data from the National Joint Registry for England and Wales. Patients with osteoarthritis who had a DePuy Corail/Pinnacle THR implanted between the establishment of the registry in 2003 and 31 December 2010 were included within analyses. There were 35 386 procedures. Cox proportional hazard models were used to analyse the extent to which the risk of revision was related to patient, surgeon and implant covariates. The overall rate of revision at five years was 2.4% (99% confidence interval 2.02 to 2.79). In the final adjusted model, we found that the risk of revision was significantly higher in patients receiving metal-on-metal (MoM: hazard ratio (HR) 1.93, p < 0.001) and ceramic-on-ceramic bearings (CoC: HR 1.55, p = 0.003) compared with the best performing bearing (metal-on-polyethylene). The risk of revision was also greater for smaller femoral stems (sizes 8 to 10: HR 1.82, p < 0.001) compared with mid-range sizes. In a secondary analysis of only patients where body mass index (BMI) data were available (n = 17 166), BMI ? 30 kg/m(2) significantly increased the risk of revision (HR 1.55, p = 0.002). The influence of the bearing on the risk of revision remained significant (MoM: HR 2.19, p < 0.001; CoC: HR 2.09, p = 0.001). The risk of revision was independent of age, gender, head size and offset, shell, liner and stem type, and surgeon characteristics. We found significant differences in failure between bearing surfaces and femoral stem size after adjustment for a range of covariates in a large cohort of single-brand cementless THRs. In this study of procedures performed since 2003, hard bearings had significantly higher rates of revision, but we found no evidence that head size had an effect. Patient characteristics, such as BMI and American Society of Anesthesiologists grade, also influence the survival of cementless components. PMID:23723267

Jameson, S S; Baker, P N; Mason, J; Rymaszewska, M; Gregg, P J; Deehan, D J; Reed, M R

2013-06-01

257

Improved survival for anatomic total shoulder prostheses.  

PubMed

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

2015-02-01

258

Prosthetic total disk replacement--can we learn from total hip replacement?  

PubMed

Total lumbar disk replacement has become a routine procedure in many countries. However, discussions regarding its use are ongoing. Issues focus on patient selection, technical limitations, and avoidance or management of complications or long-term outcomes. A review of the development of this technology, since the development of the first successful implantation of a total lumbar disk prosthesis in 1984, shows an amazing analogy to the history of total hip replacement. This article is a one-to-one comparison of the evolution of total hip and total lumbar disk replacement from "skunk works" to scientific evidence. PMID:21944590

Mayer, H Michael; Siepe, Christoph J

2011-10-01

259

Revision total hip replacement without trochanteric osteotomy.  

PubMed

Revision total hip replacement has traditionally required a trochanteric osteotomy for successful cement removal and component reinsertion. In this study the authors have concluded that in most instances the revision total hip replacement procedure can be successfully performed without trochanteric osteotomy. The advantages are underscored by the high percentage of trochanteric complications with trochanteric osteotomy for revision total hip replacement and the ease of rehabilitation without trochanteric osteotomy. Also, improved functional results without trochanteric osteotomy were noted. The specific indications for the procedure included revision total hip replacement with ununited prior trochanteric osteotomy, revision total hip replacement with femoral shaft fractures, and revision total hip replacement with stem fractures requiring only acetabular revision. The contraindications to the procedure are fibrous union or ununited trochanteric osteotomy from prior total hip replacement, severe acetabular protrusion of the acetabular component, advanced myositis ossificans, ankylosis of the hip, and advanced proximal femoral osteoporosis. The operating room records, x-rays, and outpatient records of 63 total hip revisions in 52 patients were reviewed. There was a minimum 2-year follow up with a range from two years to seven years. The patients were divided into two groups, comparing 21 trochanteric osteotomized revisions to 44 with trochanteric sparing techniques. Both groups were analyzed for age, type of implant, intraoperative perforation of femur, intraoperative femoral shaft fractures, intraoperative cortical window, component malpositioning extraneous cement, intraoperative blood loss, operating time, postoperative leg length inequality, persistent abductor weakness, average first day of ambulation, wound infection, dislocation, nonunion of the trochanter, and postoperative pain. In the nonosteotomized group, there was a 21% decreased blood loss, a 14% decrease in persistent abductor weakness, a 14% decrease in subluxation and dislocation, a 30% decrease operating time and a 50% reduction in intraoperative femoral perforation. In the osteotomized group there were six cases of fibrous union of the greater trochanter, two cases requiring removal of broken wires for trochanteric bursitis. A detailed surgical technique and representative cases are presented. In carefully selected cases, revision total hip replacement is optimally performed without trochanteric osteotomy. Postoperative trochanteric problems of nonunion, broken wires, bursitis, and abductor weakness can effectively be eliminated by avoiding trochanteric osteotomy.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3588421

Berman, A T; Salter, F L; Koenig, T

1987-05-01

260

Determining HPGe Total Detection Efficiency Using ?–? Coincidence  

SciTech Connect

Abstract Both the peak and total detection efficiencies are generally needed in order to calculate sample activity from a gamma spectroscopic measurement, except in the case of isotope specific calibration. This is particularly true when the sample is in close proximity to the detector and corrections for cascade summing effects are required to avoid significant inaccuracy in the result. These corrections use the total detection efficiency to correct for summing-in and summing-out events, and the extent of the correction depends on both the geometry and the gamma cascade for the isotope in question. Experimentally determining the total efficiency is a labor intensive endeavor requiring multiple measurements with a set of single-gamma-emitting standards. Modeling the total efficiency vs. energy may be less time consuming, but is also likely to produce less confidence in the final result. Pacific Northwest National Laboratory's Radiation Detection and Nuclear Sciences group has constructed a low background 14-crystal HPGe array for sample measurement; in all measurements, samples will be in close proximity to the germanium crystals. This close geometry and the sheer number efficiency calibrations required for the system have led us to investigate methods to simplify the efficiency calibration procedure. One method we are developing uses the Y-Y coincidence plane to isolate Compton scattering event populations, allowing experimental determination of total detection efficiency values from the measurement of a single mixed isotope standard. A description of the analysis and experimental results of this method are presented.

Erikson, Luke E.; Keillor, Martin E.; Aalseth, Craig E.; Hossbach, Todd W.; Mizouni, Leila K.; Stavenger, Timothy J.; McDonald, Benjamin S.; Lepel, Elwood A.; Greenwood, Lawrence R.; Rutherford, Crystal E.

2013-05-01

261

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

262

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

263

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

264

Total quadruple photoionization cross section of beryllium  

SciTech Connect

In a quasiclassical framework, we formulate the quadruple ionization by single-photon absorption of the Coulomb five-body problem. We present the quadruple photoionization total cross section of the ground state of beryllium for energies up to 620 eV. Our results for energies close to threshold are in agreement with the Wannier threshold law for four-electron escape. In addition, the agreement of our results with a shape formula provides support for the overall shape of our total quadruple cross section. Finally, we find that the photon energy where the maximum of the total photoionization cross section occurs for single, double, triple, and quadruple photoionization of H, He, Li, and Be, respectively, seems to follow a linear relation with the threshold energy for complete breakup of the respective element.

Emmanouilidou, Agapi [ITS, University of Oregon, Eugene, Oregon 97403-5203 (United States)

2007-11-15

265

Total Solar Eclipse of 2006 March 29  

NASA Technical Reports Server (NTRS)

On 2006 March 29, a total eclipse of the Sun will be visible from within a narrow corridor which traverses half the Earth. The path of the Moon's umbral shadow begins in Brazil and extends across the Atlantic, northern Africa, and central Asia where it ends at sunset in western Mongolia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the northern two thirds of Africa, Europe, and central Asia.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. Information on safe eclipse viewing and eclipse photography is included.

Espenak, F.; Anderson, J.

2004-01-01

266

Total Solar Eclipse of 1999 August 11  

NASA Technical Reports Server (NTRS)

On 1999 August 11, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Eastern Hemisphere. The path of the Moon's umbral shadow begins in the Atlantic and crosses central Europe, the Middle East, and India, where it ends at sunset in the Bay of Bengal. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes northeastern North America, all of Europe, northern Africa, and the western half of Asia. 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 1400 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

1997-01-01

267

COMPONENT VERSION IN MODULAR TOTAL HIP REVISION  

PubMed Central

Morphologic changes of the proximal femur make revision total hip arthroplasty challenging. Metaphyseal retroversion and diaphyseal varus are common in this scenario. Twenty-one total hip revisions using a modular femoral prosthesis were examined by obtaining three radiographs (A/P, surgical lateral, and true lateral of the femur) to assemble CAD models for determining the range of modular component positioning. An average of femoral neck anteversion was observed. Seventeen of 21 cases (81%) had retroverted metaphyseal segments (?23.2°+/?17.4°) and/or varus stems (?32.1°+/?13.0°). Neck anteversion averaged 21.4°(+/?10.0°). One of 21 cases (5%) resulted in component orientation similar to a non-modular prosthesis. Modular components provide options to accommodate proximal femoral remodeling not afforded by monobloc stems in total hip revision surgery. PMID:19742077

Kopec, Michael A.; Pemberton, Aaron; Milbrandt, Joseph C.; Allan, Gordon

2009-01-01

268

[Hypocalcemia after total thyroidectomy. Therapeutic considerations].  

PubMed

One of the post-operative complications of total thyroidectomy is the onset of a transitory or permanent hypocalcemic syndrome. Hypocalcemia is caused by different physiopathological mechanisms that operate either individually or in association (parathyroidal deficit, deficiency of bone calcium subsequent to parathyroid osteodystrophy, acute emission of calcitonin into the circulation). Calcemia levels were studied p.o. in a selected group of 25 patients who had undergone total extracapsular thyroidectomy with the apparent preservation of the parathyroid glands. Totals thyroidectomy has been performed in 15 patients with euthyroid goitre, in 4 with papillary carcinoma, in 3 with diffuse toxic goitre and in 3 with multinodular toxic goitre. Eight patients received drug and diet therapy since calcemia levels were lower than 7.5 mg/ml. Fifteen days after the operation, calcemia levels in 21 patients were subliminal and dihydrotachysterol therapy was commenced. Hypocalcemia was permanent in only one case. PMID:2287468

Piazza, L; Liardo, G; De Maria, A; Troiano, L; Terminella, A; Cannizzaro, M A

1990-09-30

269

KP solitons, total positivity, and cluster algebras  

PubMed Central

Soliton solutions of the KP equation have been studied since 1970, when Kadomtsev and Petviashvili [Kadomtsev BB, Petviashvili VI (1970) Sov Phys Dokl 15:539–541] proposed a two-dimensional nonlinear dispersive wave equation now known as the KP equation. It is well-known that the Wronskian approach to the KP equation provides a method to construct soliton solutions. The regular soliton solutions that one obtains in this way come from points of the totally nonnegative part of the Grassmannian. In this paper we explain how the theory of total positivity and cluster algebras provides a framework for understanding these soliton solutions to the KP equation. We then use this framework to give an explicit construction of certain soliton contour graphs and solve the inverse problem for soliton solutions coming from the totally positive part of the Grassmannian. PMID:21562211

Kodama, Yuji; Williams, Lauren K.

2011-01-01

270

Severe Heterotopic Ossification following Total Knee Replacement  

PubMed Central

Although the incidence of minor heterotopic ossification is probably higher than what is usually expected, severe heterotopic ossification (HO) is an extremely rare event following total knee replacement surgery. We present the case of a 66-year-old woman who initially had achieved an excellent range of motion following bilateral uncemented rotating platform total knee replacement, before presenting with pain and loss of range of motion at 2 months after surgery. Severe HO was diagnosed on X-rays. Treatment consisted of nonoperative measures only, including physiotherapy with hydrotherapy and anti-inflammatories. She eventually regained her range of motion when seen at 8 months after operation. This case illustrates that nonoperative treatment without the use of radiotherapy or surgery can be used to safely resolve stiffness caused by HO after total knee replacement. PMID:25431717

Dodds, Alexander L.; Keene, Gregory C. R.

2014-01-01

271

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

272

KP solitons, total positivity, and cluster algebras  

E-print Network

Soliton solutions of the KP equation have been studied since 1970, when Kadomtsev and Petviashvili proposed a two-dimensional nonlinear dispersive wave equation now known as the KP equation. It is well-known that the Wronskian approach to the KP equation provides a method to construct soliton solutions. The regular soliton solutions that one obtains in this way come from points of the totally non-negative part of the Grassmannian. In this paper we explain how the theory of total positivity and cluster algebras provides a framework for understanding these soliton solutions to the KP equation. We then use this framework to give an explicit construction of certain soliton contour graphs, and solve the inverse problem for soliton solutions coming from the totally positive part of the Grassmannian.

Yuji Kodama; Lauren Williams

2011-05-20

273

Total Solar Eclipse of 2008 August 01  

NASA Technical Reports Server (NTRS)

On 2008 August 01, a total eclipse of the Sun is visible from within a narrow corridor that traverses half the Earth. The path of the Moon's umbral shadow begins in northern Canada and extends across Greenland, the Arctic, central Russia, Mongolia, and China. A partial eclipse is seen within the much broader path of the Moon's penumbral shadow, which includes northeastern North America, most of Europe and Asia. 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 308 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, F.; Anderson, J.

2007-01-01

274

Correlations between corneal and total wavefront aberrations  

NASA Astrophysics Data System (ADS)

Purpose: Corneal topography data expressed as corneal aberrations are frequently used to report corneal laser surgery results. However, the optical image quality at the retina depends on all optical elements of the eye such as the human lens. Thus, the aim of this study was to investigate the correlations between the corneal and total wavefront aberrations and to discuss the importance of corneal aberrations for representing corneal laser surgery results. Methods: Thirty three eyes of 22 myopic subjects were measured with a corneal topography system and a Tschernig-type wavefront analyzer after the pupils were dilated to at least 6 mm in diameter. All measurements were centered with respect to the line of sight. Corneal and total wavefront aberrations were calculated up to the 6th Zernike order in the same reference plane. Results: Statistically significant correlations (p < 0.05) between the corneal and total wavefront aberrations were found for the astigmatism (C3,C5) and all 3rd Zernike order coefficients such as coma (C7,C8). No statistically significant correlations were found for all 4th to 6th order Zernike coefficients except for the 5th order horizontal coma C18 (p equals 0.003). On average, all Zernike coefficients for the corneal aberrations were found to be larger compared to Zernike coefficients for the total wavefront aberrations. Conclusions: Corneal aberrations are only of limited use for representing the optical quality of the human eye after corneal laser surgery. This is due to the lack of correlation between corneal and total wavefront aberrations in most of the higher order aberrations. Besides this, the data present in this study yield towards an aberration balancing between corneal aberrations and the optical elements within the eye that reduces the aberration from the cornea by a certain degree. Consequently, ideal customized ablations have to take both, corneal and total wavefront aberrations, into consideration.

Mrochen, Michael; Jankov, Mirko; Bueeler, Michael; Seiler, Theo

2002-06-01

275

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

276

Failure of aseptic revision total knee arthroplasties.  

PubMed

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 Håkon L; Skredderstuen, Arne; Hallan, Geir; Furnes, Ove

2015-02-01

277

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

278

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

279

Formal total synthesis of (±)-cortistatin A  

PubMed Central

A second-generation synthesis of the pentacyclic core of the cortistatins, a family of rearranged steroidal alkaloids that have recently attracted much attention, is reported. The improved sequence provides access to significant quantities of this key compound, which enabled a formal total synthesis of (±)-cortistatin A by conversion to the key Nicolaou/Hirama dienone. It is anticipated that this new, robust route to the pentacyclic core will facilitate the total synthesis of a range of natural products in the cortistatin family, as well as the construction of key structural analogs to probe the promising biological activity of these important compounds. PMID:20672014

Simmons, Eric M.; Hardin-Narayan, Alison R.; Guo, Xuelei; Sarpong, Richmond

2010-01-01

280

Total joint arthroplasty: tips for improving efficiency.  

PubMed

Total joint arthroplasty is a very successful procedure that alleviates pain in arthritic patients. However, our current healthcare delivery system may not be able to provide the value of arthroplasty to match the demand in our increasing arthritic population. Increasing hospital efficiency and value for patients needing total joint replacement will bring this pain-relieving procedure to more patients with benefits to surgeons and hospitals. This article reviews segments in the knee arthroplasty pathway that will provide efficiency and value when they are optimized. PMID:24911640

Gittins, Mark; Doucette, Diane

2014-03-01

281

The $?^* ?^*$ total cross section in NLA BFKL  

E-print Network

We study the $\\gamma^* \\gamma^*$ total cross section in the NLA BFKL approach. We have extracted the NLO corrections to the photon impact factor from two recent papers of Balitsky and Chirilli and Chirilli and Kovchegov and used them to build several representations of the total cross section, equivalent within the NLA. We have combined these different representations with two among the most common methods for the optimization of a perturbative series, namely PMS and BLM, and compared their behavior with the energy with the only available experimental data, those from the LEP2 collider.

Dmitry Yu. Ivanov; Beatrice Murdaca; Alessandro Papa

2014-11-16

282

Determination of total solutes in synfuel wastewaters  

SciTech Connect

Efforts to investigate both lyophilization and the measurement of colligative properties as an indication of total solute content are described. The objective of the work described is to develop a method for measuring total dissolved material in retort wastewaters which is simple and rugged enough to be performed in a field laboratory in support of pollution control tests. The analysis should also be rapid enough to provide timely and pertinent data to the pollution control plant operator. To be of most value, the technique developed also should be applicable to other synfuel wastewaters, most of which contain similar major components as oil shale retort waters. 4 references, 1 table.

Wallace, J.R.; Bonomo, F.S.

1984-03-01

283

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

284

Total Teleportation of an Entangled State  

E-print Network

We present a setup for a direct, total teleportation of a single-particle entangled state. Our scheme consists of a parametric down-conversion source, which emits a pair of entangled photons, and a dual Bell measurement system with two beam splitters and two pairs of detectors. An entangled state shared by a pair of beams can be directly transferred to another pair of beams with a 50% probability of success. By a straightforward generalization of the scheme, total teleportation of a multi-particle entangled state can also be performed.

Hai-Woong Lee

2001-04-19

285

Total synthesis of sandresolide B and amphilectolide.  

PubMed

The total synthesis of the diterpenoids sandresolide B and amphilectolide from a common furan building block is presented. Key steps include palladium-mediated carbonylation, lanthanide catalyzed ring closure, Myers alkylation, intramolecular Friedel-Crafts acylation, photooxygenation, and a Kornblum-DeLaMare rearrangement. PMID:24308854

Chen, Ingrid T; Baitinger, Irina; Schreyer, Lucas; Trauner, Dirk

2014-01-01

286

The management of chronic total coronary occlusions  

Microsoft Academic Search

Although recent consensus has clearly defined chronic total occlusions (CTO), attempted per- cutaneous coronary intervention (PCI) remains low. Histopathologically, CTOs are characterized by fibrous caps, varying degrees of plaques, and neovascularization, with both increasing with the age of the CTO. Multiple registries and studies show that successful PCI of CTOs can improve symptoms, left ventric- ular function, and mortality. There

A. CUNEO; U. TEBBE

2008-01-01

287

PROCEDURE FOR ESTIMATING PERMANENT TOTAL ENCLOSURE COSTS  

EPA Science Inventory

The paper discusses a procedure for estimating permanent total enclosure (PTE) costs. (NOTE: Industries that use add-on control devices must adequately capture emissions before delivering them to the control device. One way to capture emissions is to use PTEs, enclosures that mee...

288

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

289

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

290

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

291

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

292

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

293

An efficient total synthesis of (-)-epothilone B.  

PubMed

An efficient total synthesis of (-)-epothilone B has been achieved in ca. 8% yield over 11 steps from 9 (or 10 steps from 7/8), which features a bissiloxane-tethered ring closing metathesis reaction to approach the trisubstituted (Z) double bond and forms a new basis for further development of an industrial process for epothilone B and ixabepilone. PMID:23214997

Wang, Jie; Sun, Bing-Feng; Cui, Kai; Lin, Guo-Qiang

2012-12-21

294

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.

295

Iterative methods for total variation denoising  

Microsoft Academic Search

Total variation (TV) methods are very effective for recovering ``blocky,`` possibly discontinuous, images from noisy data. A fixed point algorithm for minimizing a TV-penalized least squares functional is presented and compared with existing minimization schemes. A variant of the cell-centered finite difference multigrid method of Ewing and Shen is implemented for solving the (large, sparse) linear subproblems. Numerical results are

C. R. Vogel; M. E. Oman

1996-01-01

296

Mineral Analysis of Whole Grain Total Cereal  

ERIC Educational Resources Information Center

The quantitative analysis of elemental iron in Whole Grain Total Cereal using visible spectroscopy is suitable for a general chemistry course for science or nonscience majors. The more extensive mineral analysis, specifically for the elements iron, calcium and zinc, is suitable for an instrumental or quantitative analysis chemistry course.

Hooker, Paul

2005-01-01

297

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

298

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

299

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

300

Total Solar Irradiance Satellite Composites and their  

E-print Network

Chapter 12 Total Solar Irradiance Satellite Composites and their Phenomenological Effect on Climate. Phenomenological solar signature on climate 310 9. Conclusion 312 1. INTRODUCTION A contiguoustotal solar from each other, in particular about whether the TSI minimum during solar Cycles 22e23 (1995

Scafetta, Nicola

301

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

302

Production Function Geometry with "Knightian" Total Product  

ERIC Educational Resources Information Center

Authors of principles and price theory textbooks generally illustrate short-run production using a total product curve that displays first increasing and then diminishing marginal returns to employment of the variable input(s). Although it seems reasonable that a temporary range of increasing returns to variable inputs will likely occur as…

Truett, Dale B.; Truett, Lila J.

2007-01-01

303

Recent Developments in Total Variation Image Restoration  

E-print Network

Recent Developments in Total Variation Image Restoration T. Chan S. Esedoglu F. Park A. Yip for image restoration. More recently, there has been a resurgence of interest and exciting new develop of restoration problems, and remain one of the most active areas of research in mathematical image processing

Esedoglu, Selim

304

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

305

Enantiospecific total synthesis of (-)-bengamide E.  

PubMed

Total synthesis of the polyhydroxy caprolactam amide natural product, bengamide E, is accomplished starting from tartaric acid. Key reactions in the synthesis include desymmetrization of the bis(dimethylamide) unit of tartaric acid, Zn(BH(4))(2)-mediated anti-selective reduction, and a Horner-Wadsworth-Emmons olefination. PMID:23208822

Metri, Prashant K; Schiess, Raphael; Prasad, Kavirayani R

2013-02-01

306

Banquet Registration ____ (number of tickets @) $70 = Total $_________  

E-print Network

Banquet Registration ____ (number of tickets @) $70 = Total $_________ Name(s) of attendees for the annual HVEI Banquet featuring guest speaker Dr. Carol O'Sullivan, professor of Visual Computing Trinity, private car, on foot, or some other means. 2012 Human Vision and Electronic Imaging Banquet Reservation

Pappas, Thrasyvoulos N.

307

Modular Uncemented Tricompartmental Total Knee Arthroplasty  

Microsoft Academic Search

Background: The incidence of posttraumatic osteoarthrosis, especially in younger patients, increases. In different studies total knee arthroplasty (TKA) is only indicated in 0–12% of cases of posttraumatic osteoarthrosis, because most authors feel that the indication for TKA in younger patients should be narrowly restricted. The most common indications for TKA include primary idiopathic osteoarthrosis and rheumatoid arthritis predominantly in patients

Gunther O. Hofmann; Oliver Wolf; Thomas Mückley

2005-01-01

308

Surgical approaches for total hip arthroplasty  

Microsoft Academic Search

Total hip replacement is a commonly performed procedure. The National Joint Registry for England and Wales identifies the four most commonly used approaches. An understanding of the relevant anatomy, benefits and common complications for each approach is essential core knowledge for all orthopaedic surgeons. In this article we provide an overview of our preferred technique for the surgical approaches commonly

Andrew Graham Sloan; Henry Wynn Jones; Martyn Lonsdale Porter; Kevin Hardinge

2010-01-01

309

Total pollution effect of urban surface runoff  

Microsoft Academic Search

For pollution research with regard to urban surface runoff, most sampling strategies to date have focused on differences in land usage. With single land-use sampling, total surface runoff pollution effect cannot be evaluated unless every land usage spot is monitored. Through a new sampling strategy known as mixed stormwater sampling for a street community at discharge outlet adjacent to river,

Hongbing LUO; Lin LUO; Gu HUANG; Ping LIU; Jingxian LI; Sheng HU; Fuxiang WANG; Rui XU; Xiaoxue HUANG

2009-01-01

310

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

311

High technology workers and total rewards  

Microsoft Academic Search

This literature review suggests that the Total Rewards approach has some promise in the management of high technology workers primarily because of its broad definition of rewards. It also suggests that the rewards preference profile of high technology workers is different from that of other occupational categories and rewards programs for high technology workers should therefore be different. Research directions

John W. Medcof; Steven Rumpel

2007-01-01

312

TOTAL REFLUX OPERATION OF MULTIVESSEL BATCH DISTILLATION  

E-print Network

the operation is switched between total re ux operation and dumping the product i.e., the condenser holdup products are collected in the condenser drum and in the reboiler. Another alternative is to "invert multivessel batch distillation column by calculating in advance the nal holdup in each vessel and then using

Skogestad, Sigurd

313

TOTAL REFLUX OPERATION OF MULTIVESSEL BATCH DISTILLATION  

E-print Network

between total reflux operation and dumping the product (i.e., the condenser holdup is introduced in the condenser drum and in the reboiler. Another alternative is to ''invert'' the column by charging the feed column by calculating in advance the final holdup in each vessel and then using a level control system

Skogestad, Sigurd

314

Total versus quantum correlations in quantum states  

SciTech Connect

On the premises that total correlations in a bipartite quantum state are measured by the quantum mutual information, and that separation of total correlations into quantum and classical parts satisfies an intuitive dominance relation, we examine to what extent various entropic entanglement measures, such as the distillable entanglement, the relative entropy entanglement, the squashed entanglement, the entanglement cost, and the entanglement of formation, can be regarded as consistent measures of quantum correlations. We illustrate that the entanglement of formation often overestimates quantum correlations and thus is too big to be a genuine measure of quantum correlations. This indicates that the entanglement of formation does not quantify the quantum correlations intrinsic to a quantum state, but rather characterizes the pure entanglement needed to build the quantum state via local operations and classical communication. Furthermore, it has the consequence that, if the additive conjecture for the entanglement of formation is true (as is widely believed), then the entanglement cost, which is an operationally defined measure of entanglement with significant physical meaning, cannot be a consistent measure of quantum correlations in the sense that it may exceed total correlations. Alternatively, if the entanglement cost is dominated by total correlations, as our intuition suggests, then we can immediately disprove the additive conjecture. Both scenarios have their counterintuitive and appealing aspects, and a natural challenge arising in this context is to prove or disprove that the entanglement cost is dominated by the quantum mutual information.

Li Nan; Luo Shunlong [Academy of Mathematics and Systems Science, Chinese Academy of Sciences, 100080 Beijing (China)

2007-09-15

315

Periprosthetic fractures around total knee arthroplasty  

PubMed Central

INTRODUCTION The number of total knee arthroplasties performed continues to rise annually and it would be expected that complications, which include periprosthetic fractures, will also therefore become more commonplace. This article reviews the current literature regarding this injury and identifies the treatment principles that enable patients to regain optimal function. METHODS A comprehensive search of the Pubmed and Embase™ databases was performed to identify relevant articles. Keywords and MeSH (Medical Subject Headings) terms included in the search strategy were ‘periprosthetic fracture(s)’, ‘femur’, ‘tibia’, ‘patella(r)’, ‘complication(s)’, ‘failure(s)’, ‘risk(s)’, ‘prevalence’, ‘incidence’, ‘epidemiology’ and ‘classification(s)’. The search was limited to all articles published in English and reference lists from the original articles were reviewed to identify pertinent articles to include in this review. A total number of 43 studies were identified. RESULTS Common treatment aims have been identified when managing patients with a periprosthetic fracture around total knee arthoplasty. The main criterion that determines which option to choose is the degree of remaining bone stock and the amount of fracture displacement. CONCLUSIONS Treatment of a periprosthetic fracture around total knee arthroplasty will either be non-operative, osteosynthesis or revision arthroplasty. It is imperative that a suitable option is chosen and based on the published literature, pathways are outlined to aid the surgeon. PMID:22943223

Sarmah, SS; Patel, S; Reading, G; El-Husseiny, M; Douglas, S; Haddad, FS

2012-01-01

316

Total Quality Management's Challenge to Urban Schools.  

ERIC Educational Resources Information Center

With political support, Total Quality Management principles can help urban schools redefine schools' role, purpose, and responsibilities; focus on continuous improvement; plan comprehensive leadership training; create staff development confronting staff attitudes and beliefs; use research- and practice-based information to guide policy and…

Hixson, Judson; Lovelace, Kay

1992-01-01

317

Total anomalous systemic and pulmonary venous connection.  

PubMed

Total anomalous systemic and pulmonary venous connection is an extremely rare congenital cardiac anomaly. We present our unique experience of managing this complex partially diagnosed cardiac anomaly in a 16-month-old boy. The systemic venous anomaly was not detected during the initial preoperative evaluation. He was doing well on follow-up, with normal pulmonary artery pressure. PMID:24887855

Mishra, Amit; Sharma, Pranav; Shah, Ritesh; Oswal, Nilesh; Rana, Yashpal

2015-01-01

318

Efforts toward the Total Synthesis of (-)-Kendomycin  

E-print Network

Efforts toward the Total Synthesis of (-)-Kendomycin David R. Williams and Khalida Shamim, Smith and co-workers have recently described conditions for 16-membered macrocyclization by RCM, albeit. 2005, 7, 1529. (6) Smith, A. B.; Mesaros, E. F.; Meyer, E. A. J. Am. Chem. Soc. 2005, 127, 6948

Williams, David R.

319

Enantioselective Total Synthesis of Plectosphaeroic Acid B  

PubMed Central

The first total synthesis of a member of the plectosphaeroic acid family of fungal natural products is reported. Key steps include the late-stage formation of the hindered N6–C9? bond and stereoselective introduction of the two methylthio substituents. PMID:23452064

Jabri, Salman Y.; Overman, Larry E.

2013-01-01

320

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

321

Total Wrist Replacement: A Retrospective Comparative Study  

PubMed Central

Purpose?Total wrist arthroplasty (TWA) is an evolving procedure for the treatment of arthritis of the wrist joint. The purpose of this study is to compare outcomes of three different total wrist implants. Methods?A retrospective review of the Biaxial, Universal 2, and Re-Motion total wrist arthroplasties was performed. Patients were evaluated for clinical outcome, radiographic analysis, review of complications (incidence and type), and conversion to wrist fusion. Patient function measures included: the Mayo wrist score, the Patient Related Wrist Evaluation, and Disabilities of Arm, Shoulder, and Hand (DASH) score. Results?Forty-six wrist implants were performed in 39 patients. There were 36 rheumatoid and 10 posttraumatic cases. The average follow-up was 6 years (3.5 to 15). The total wrist inserted included 16 resectional arthroplasties (Biaxial) and 30 resurfacing designs (Universal 2 and Re-Motion). Nine implant failures were noted. Causes for arthroplasty failure included distal component implant loosening and wrist instability. Salvage procedures included revision TWA or wrist fusion. In successful cases, flexion and extension motion averaged 30 and 38 degrees, respectively, and grip strength improved by 3 kg. Mayo wrist scores, in successful cases, increased from 40 (preoperative) to 76 (postoperative). The Mayo wrist scores for posttraumatic conditions averaged 87 points versus 71 points for rheumatoid arthritis. The average DASH score for the two resurfacing designs were 20 and 37, and 48 for the resectional arthroplasty design. Discussion?Total wrist replacement maintains itself and provides good pain relief and functional motion in over 80% of all cases and in 97% of resurfacing implants. Better results were correlated with improved distal component fixation and minimal resection of the distal radius. Level of Evidence?Level 3 Case Control PMID:24179722

Cooney, William; Manuel, Jennifer; Froelich, John; Rizzo, Marco

2012-01-01

322

A Fix by Total Solar Eclipse  

NASA Astrophysics Data System (ADS)

In anticipation of the TOTAL Solar Eclipse on 11 August 1999 (see the January/February issue of Navigation News), it seemed very appropriate to repeat this short article by one of the Institute's most respected Fellows. It was first published in Vol. VII, October 1954.A TOTAL eclipse of the Sun provides an opportunity, rare though it may be, of obtaining an instantaneous fix from the Sun alone. Eclipses vary greatly in character, in position on the Earth, in the width of the path of totality, in the duration, and also in the direction of the path. However, the shadow of the Moon cast by the Sun is always a right circular cone which, in the case of a total eclipse, intersects the Earth's surface at some point before its vertex. Owing to the motion of the Moon in its orbit round the Earth, the shadow moves at a speed of about 2000 m.p.h. from west to east (it varies considerably according to the distance of the Moon from the Earth). The intersection of this cone with the Earth's surface is an ellipse, which moves over the surface at speeds which are very high when the cone is nearly tangential (i.e. when the Sun's altitude is low) and at speeds as low as about 1000 m.p.h., when the eclipse is central over the equator at noon and the Earth's rotation has its maximum effect. The speed of the shadow is generally low enough to give a position line of considerable accuracy from the observed time of either second or third contacts, that is the beginning or ending of the total phase. An error of 1 second corresponds, in the most favourable case, to about one-third of a mile. The position line is, of course, the portion of the elliptic shadow corresponding to the observed phase and time; these can be precomputed.

Sadler, D. H.

323

Total ozone variations at Reykjavik since 1957  

SciTech Connect

Total ozone measurements using a Dobson spectrophotometer have been performed on a regular basis at Reykjavik (65 deg 08 min N, 21 deg 54 min 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.

Bjarnason, G.G.; Rognvaldsson, O.E.; Sigfusson, T.I.; Jakobsson, T.; Thorkelsson, B. [Univ. of Iceland, Reykjavik (Iceland)]|[Icelandic Meteorological Office, Reykjavik (Iceland)

1993-12-01

324

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

325

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

326

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...

327

Progress in the Total Synthesis of Rocaglamide  

PubMed Central

The first cyclopenta[b]benzofuran derivative, rocaglamide, from Aglaia elliptifolia, was found to exhibit considerable insecticidal activities and excellent potential as a therapeutic agent candidate in cancer chemotherapy; the genus Aglaia has been subjected to further investigation. Both the structural complexity of rocaglamide and its significant activity make it an attractive synthetic target. Stereoselective synthesis of the dense substitution pattern of these targets is a formidable synthetic challenge: the molecules bear five contiguous stereocenters and cis aryl groups on adjacent carbons. In past years of effort, only a handful of completed total syntheses have been reported, evidence of the difficulties associated with the synthesis of rocaglate natural products. The advance on total synthesis of rocaglamide was mainly reviewed from intramolecular cyclization and biomimetic cycloaddition approach. PMID:24052818

Cai, Xiao-hua; Xie, Bing; Guo, Hui

2011-01-01

328

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

329

Early death following primary total hip arthroplasty.  

PubMed

This study aims to describe the timing, cause of death, and excess surgical mortality associated with primary total hip arthroplasty when compared to a population awaiting primary total hip arthroplasty. Mortality rates were calculated at cutoffs of 30 and 90 days post-operation or following the addition to the waiting list. Cause of death was recorded from the death certificate. An excess surgical mortality of 0.256% at 30 days (P = 0.002) and 0.025% at 90 days post-operation (P = 0.892), unaffected by age or gender, was seen with myocardial infarction and pneumonia the cause of death in the majority of cases. By using a more appropriate control population, an excess surgical mortality at 30 days post-operation is demonstrated; the effect diminishes at 90 days post-operation. PMID:24650899

Jones, Mark D; Parry, Michael C; Whitehouse, Michael R; Blom, Ashley W

2014-08-01

330

Total synthesis of all (–)-Agelastatin alkaloids  

PubMed Central

The pyrrole-imidazole family of marine alkaloids, derived from linear clathrodin-like precursors, constitutes a diverse array of structurally complex natural products. The bioactive agelastatins are members of this family that possess a tetracyclic molecular framework incorporating C4–C8 and C7–N12 bond connectivities. We provide a hypothesis for the formation of the unique agelastatin architecture that maximally exploits the intrinsic chemistry of plausible biosynthetic precursors. We report the concise enantioselective total syntheses of all known agelastatin alkaloids including the first total syntheses of agelastatins C, D, E, and F. Our gram-scale chemical synthesis of agelastatin A was inspired by our hypothesis for the biogenesis of the cyclopentane C-ring and required the development of new transformations including an imidazolone-forming annulation reaction and a carbohydroxylative trapping of imidazolones. PMID:21218186

Siegel, Dustin S.; Han, Sunkyu

2010-01-01

331

Rating systems for total knee replacement.  

PubMed

The objective assessment of outcome of surgical procedures is assuming increasing significance as the culture of audit and revalidation advances. There is a clear need for surgeons in all fields, but especially in Orthopaedics, to be familiar with the available scoring systems and their relative strengths and weaknesses. It is clear from a recent survey of BASK members' practice that there is little consensus about which system to use (addendum). This review presents a summary of the scoring systems available for the assessment of patients undergoing total knee replacement. These scores are described in detail and their relative merits discussed. None of the systems reviewed is perfect but those developed most recently do appear to offer advantages over older systems. Overall, the Western Ontario and McMaster University Osteoarthritis Index, Short Form 36 and Oxford Knee Score have undergone the most thorough assessment of reliability and validity and are therefore appropriate for the assessment of outcome after total knee replacement. PMID:12424032

Davies, Andrew P

2002-12-01

332

The first total laparoscopic pancreatoduodenectomy in Poland.  

PubMed

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 3(rd) 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; P?dziwiatr, Micha?; Wierdak, Mateusz; Mat?ok, Maciej; Zaj?c, Ma?gorzata

2014-09-01

333

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

334

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

335

Generalized Principles of Unchanging Total Concentration  

PubMed Central

We consider transport of multiple reacting species under the continuum assumption in situations such as those that frequently arise in electroanalytical chemistry. Under certain limitations, it has been shown that the total species concentration (as defined by Oldham and Feldberg1) of such a system is uniform and constant. In this work, we extend the limits of the previous analysis to enable greater applicability. This is accomplished by using either of two new dependent variables, which are generalizations of the concept of total concentration. Then conditions are determined under which the dependent variable will be uniform, and constant in time. From a practical viewpoint, the described formalism allows one to simplify the multispecies transport problem formulation by eliminating one equation from the system of governing equations. PMID:16853140

Kottke, Peter A.; Fedorov, Andrei G.

2008-01-01

336

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

337

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

338

Dilemmas in Uncemented Total Hip Arthroplasty  

Microsoft Academic Search

In this thesis, different aspects that are related to the survivorship and clinical outcome in uncemented total hip arthroplasty are analysed. In Chapter 2, the survival rate, Harris Hip score and radiographic features of a proximally hydroxyapatite coated titanium alloy femoral stem (Bi-Metric, Biomet) was evaluated. In conclusion, at an average follow-up of 8 years, this proximally HA-coated femoral component

J. H. M. Goosen

2009-01-01

339

Progressive Decoherence and Total Environmental Disentanglement  

Microsoft Academic Search

The simple stationary decoherence of a two-state quantum system is discussed from a new viewpoint of environmental entanglement.\\u000a My work emphasizes that an unconditional local state must be totally disentangled from the rest of the universe. It has been\\u000a known for longthat the loss of coherence within the given local system is gradual. Also the quantum correlations between the\\u000a local

Lajos Diósi

2003-01-01

340

Why Revision Total Hip Arthroplasty Fails  

Microsoft Academic Search

Current outcomes data on revision total hip arthroplasty focuses on specific implants and techniques rather than more general\\u000a outcomes. We therefore examined a large consecutive series of failed THAs undergoing revision to determine if survivorship\\u000a and modes of failure differ in comparison to the current data. We retrospectively reviewed the medical records of 1100 revision\\u000a THAs. The minimum followup was

Bryan D. Springer; Thomas K. Fehring; William L. Griffin; Susan M. Odum; John L. Masonis

2009-01-01

341

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

342

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

343

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

344

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

345

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

346

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

347

Total Lightning Activity as Observed from Space  

NASA Technical Reports Server (NTRS)

Our knowledge of the global distribution of lightning has improved dramatically since the 1995 launch of the Optical Transient Detector (OTD), followed in 1997 by the launch of the Lightning Imaging Sensor (LIS). Together, these instruments have generated a continuous seven-year record of global lightning activity. These lightning observations have provided a new global perspective on total lightning activity. For the first time, total lightning activity (CG and IC) has been observed over large regions with high detection efficiencies and accurate geographic location. This has produced new insights into lightning distributions, times of occurrence and variability. It has produced a revised global flash rate estimate (44 flashes per second) and has lead to a new realization of the significance of total ligh&g activity in severe weather. Accurate flash rate estimates are now available for areas of the earth (+/- 72 deg. latitude). Ocean-land contrasts as a function of season are clearly reveled, as are orographic effects and seasonal and interannual variability. The data set indicates that air mass thunderstorms, not large storm system dominate global activity. The ability of LIS and OTD to detect total lightning has lead to improved insight into the correlation between lightning and storm development. The relationship between updraft development and lightning activity is now well established and presents an opportunity for providing a new mechanism for remotely monitoring storm development. In this concept, lightning would serve as a surrogate for updraft velocity. It is anticipated that this capability could lead to significantly improved severe weather warning times and reduced false warning rates.

Christian, Hugh J.

2004-01-01

348

Total Lightning Activity as Observed from Space  

NASA Technical Reports Server (NTRS)

ABSTRACT: Our knowledge of the global distribution of lightning has improved dramatically since the 1995 launch of the Optical Transient Detector (OTD), followed in 1997 by the launch of the Lightning Imaging Sensor (LIS). Together, these instruments have generated a continuous seven-year record of global lightning activity. These lightning observations have provided a new global perspective on total lightning activity. For the first time, total lightning activity (CG and IC) has been observed over large regions with high detection efficiencies and accurate geographic location. This has produced new insights into lightning distributions, times of occurrence and variability. It has produced a revised global flash rate estimate (44 flashes per second) and has lead to a new realization of the significance of total ligh&g activity in severe weather. Accurate flash rate estimates are now available for areas of the earth (+/- 72 deg. latitude). Ocean-land contrasts as a function of season are clearly reveled, as are orographic effects and seasonal and interannual variability. The data set indicates that air mass thunderstorms, not large storm system dominate global activity. The ability of LIS and OTD to detect total lightning has lead to improved insight into the correlation between lightning and storm development. The relationship between updraft development and lightning activity is now well established and presents an opportunity for providing a new mechanism for remotely monitoring storm development. In this concept, lightning would serve as a surrogate for updraft velocity. It is anticipated that this capability could lead to significantly improved severe weather warning times and reduced false warning rates.

Christian, Hugh J.

2004-01-01

349

Abel inversion using total variation regularization: applications  

Microsoft Academic Search

We apply total-variation (TV) regularization methods to Abel inversion tomography. Inversions are performed using the fixed-point iteration method and the regularization parameter is chosen such that the resulting data fidelity approximates the known or estimated statistical character of the noisy data. Five one-dimensional (1D) examples illustrate the favorable characteristics of TV-regularized solutions: noise suppression and density discontinuity preservation. Experimental and

Thomas J. Asaki; Patrick R. Campbell; Rick Chartrand; Collin E. Powell; Kevin R. Vixie; Brendt E. Wohlberg

2006-01-01

350

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

351

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

352

Totally Chlorine Free Bleaching of Organosolv Pulps  

Microsoft Academic Search

Populustremula* tremuloides wood samples were processed in acetic acid–water–HCl media (Acetosolv pulping) and then subjected to totally chlorine free (TCF) bleaching sequences in order to obtain dissolving grade pulps. Several bleaching sequences (ZEQP1P2, EOQP1P2, EOPaaQP1P2, and EOZQP1P2) were assayed for this purpose. The best results corresponded to an EOZQP1P2 sequence, which led to pulps suitable for the manufacture of viscose

J. L. Alonso; J. C. Parajó; R. Yáñez

2003-01-01

353

Backside Wear in Modern Total Knee Designs  

Microsoft Academic Search

Although modularity affords various options to the orthopedic surgeon, these benefits come at a price. The unintended bearing\\u000a surface between the back surface of the tibial insert and the metallic tray results in micromotion leading to polyethylene\\u000a wear debris. The objective of this study was to examine the backside wear of tibial inserts from three modern total knee designs\\u000a with

Prakash Jayabalan; Bridgette D. Furman; Jocelyn M. Cottrell; Timothy M. Wright

2007-01-01

354

Molecular Expressions: Total Internal Reflection Fluorescence Microscopy  

NSDL National Science Digital Library

This item is a comprehensive tutorial on TIRFM (total internal reflection fluorescence microscopy). The technology, developed in the 1980's, is used extensively in cell and molecular biology for observation of thin regions of a specimen, often less than 200nm. This tutorial includes fundamental concepts, theoretical aspects, basic and advanced microscope configurations, and a set of Java applets that depict the fluorophore excitation process and instrument configurations.

Davidson, Michael; Abramowitz, Mortimer; Axelrod, Daniel

2008-08-23

355

Budgeted Revenues: Total: $ 0.00  

E-print Network

Budgeted Revenues: Total: $ 0.00 Project Approved Pending Items Number Budget (Not Encumbered) FY12.05 $188.69 $0.00 $227.36 $0.00 $227.36 Project Approved Pending Items Number Budget (Not Encumbered,414.37 In Progress National Instruments LabView 13-002 $20,599.00 $20,628.08 $0.00 ($29.08) $0.00 ($29

Veiga, Pedro Manuel Barbosa

356

Communicating Total Reward at O2  

Microsoft Academic Search

Purpose – This paper looks at reward structures for employees at O2. Design\\/methodology\\/approach – O2 gave pensions and share plans a complete communications facelift. They set up drop-in surgeries and introduced a Total Reward website. Findings – O2 saw a huge increase in understanding of how share plans work. There was a steady increase in pension scheme membership and the

Rachel Fyffe

2007-01-01

357

Total displacement functions for SiC  

NASA Astrophysics Data System (ADS)

Numerical solutions for the displacement functions in SiC are determined from the coupled integro-differential equations governing the total number of type- j atoms displaced in the collision cascade initiated by a primary knock-on atom (PKA) of type- i and energy E. Atomic scattering cross sections based on either the inverse power law screening potentials or the Ziegler, Biersack, and Littmark (ZBL) universal screening potential are used in the calculation of the displacement functions. The electronic stopping powers used in the calculations are either derived from the LSS and Bethe-Bloch theories or generated from the SRIM-96 electronic stopping power data base. The displacement functions determined using LSS/Bethe-Bloch electronic stopping powers are 25 to 100% larger than the displacement functions determined using the electronic stopping powers generated by SRIM-96. The total number of displaced atoms determined numerically for each PKA type, based on ZBL scattering cross sections and SRIM-96 electronic stopping powers, is in excellent agreement, over the entire range of PKA energies (10 eV to 10 MeV), with the total number of displacements determined by full cascade Monte Carlo simulations using the TRIM code in SRIM-96.

Weber, W. J.; Williford, R. E.; Sickafus, K. E.

1997-04-01

358

Total hip arthroplasty revision in elderly patients.  

PubMed

In the last years, the number of total hip arthroplasty is increased both in young patients and elderly with a poor bone quality due to extension of surgical indications. According to this trend, also revision surgery showed a growth of its number, especially in elderly patients, because of implant loosening, failed osseointegration of prosthetic components, errors in biomechanical restoration and infections. The aim of this study is to analyze life quality improvement through evaluation of articular functionality and postoperative pain, and to examine osseointegration of implant components with periprosthetic bone. During total hip arthroplasty revision, the orthopedic surgeon often has to face complex cases, especially in elderly patients with a preexisting status of poor bone quality and sarcopenia. In these cases, a correct planning and a surgical procedure well-executed are able to ensure a good outcome that led to pain relief and functional recovery. Furthermore anti-osteoporotic therapy surely represents a useful resource both in primary total hip arthroplasty and in revisions, mainly for elderly patients with a poor bone quality. PMID:24046034

Gasbarra, Elena; Perrone, Fabio Luigi; Celi, Monica; Rao, Cecilia; Feola, Maurizio; Cuozzo, Nicola; Tarantino, Umberto

2013-10-01

359

The error in total error reduction.  

PubMed

Most models of human and animal learning assume that learning is proportional to the discrepancy between a delivered outcome and the outcome predicted by all cues present during that trial (i.e., total error across a stimulus compound). This total error reduction (TER) view has been implemented in connectionist and artificial neural network models to describe the conditions under which weights between units change. Electrophysiological work has revealed that the activity of dopamine neurons is correlated with the total error signal in models of reward learning. Similar neural mechanisms presumably support fear conditioning, human contingency learning, and other types of learning. Using a computational modeling approach, we compared several TER models of associative learning to an alternative model that rejects the TER assumption in favor of local error reduction (LER), which assumes that learning about each cue is proportional to the discrepancy between the delivered outcome and the outcome predicted by that specific cue on that trial. The LER model provided a better fit to the reviewed data than the TER models. Given the superiority of the LER model with the present data sets, acceptance of TER should be tempered. PMID:23891930

Witnauer, James E; Urcelay, Gonzalo P; Miller, Ralph R

2014-02-01

360

The Last Total Eclipse of the Millenium  

NSDL National Science Digital Library

On August 11, 1999, a rare total solar eclipse will cast its shadow across the earth. Part of the rarity of this year's eclipse is the fact that the path of totality (the viewing track of the total eclipse) will cover so much inhabited land. First hitting soil in Cornwall, UK, the moon's umbra (complete shadow) will cut a path relatively close to many major cities of Europe, the Middle East, and South Asia, finally ending over India in the Bay of Bengal. Cities that will view the eclipse include London, Paris, Munich, Bucharest, Baghdad, Karachi, and Ahmadabad. Of course, earthbound observers will be dependent upon clear skies to view the event. Statistical calculations of climatological data have helped determine the areas of highest probability for good weather. In addition to the wonderful spectacle, the eclipse also offers researchers unique opportunities to collect data on the sun's corona. Although the umbra will not pass over North America directly, satellite technology affords North Americans the opportunity to view the eclipse via live Webcasts (see above). The ten resources listed provide articles, information, and data in preparation for this last eclipse of the millennium.

Ramanujan, Krishna.

361

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

362

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

363

The importance of the anterior longitudinal ligament in lumbar disc arthroplasty: 36-Month follow-up experience in extreme lateral total disc replacement  

PubMed Central

Background Current total disc replacement (TDR) for lumbar spine requires an anterior approach for implantation but presents inherent limitations, including risks to the abdominal structures, as well as resection of the anterior longitudinal ligament. By approaching the spine laterally, it is possible to preserve the stabilizing ligaments, which are a natural restraint to excessive rotations and translations, and thereby help to minimize facet stresses. This less invasive approach also offers a biomechanical advantage of placement of the device over the ring apophysis bilaterally; importantly, it also offers a greater opportunity for safer revision surgery, if necessary, by avoiding scarring of the anterior vasculature. We present the clinical and radiologic results of a lateral TDR device from a prospective single-center study. Methods A new metal-on-metal TDR device designed for implantation through a true lateral, retroperitoneal, transpsoatic approach (extreme lateral interbody fusion) was implanted in 36 patients with discography-confirmed 1- or 2-level degenerative disc disease. Clinical (pain and function) and radiographic (range of motion) outcome assessments were prospectively collected preoperatively, postoperatively, and serially up to a minimum of 36 months’ follow-up. Results Between December 2005 and December 2006, 36 surgeries were performed in 16 men and 20 women (mean age, 42.6 years). These included 15 single-level TDR procedures at L3-4 or L4-5, 3 2-level TDR procedures spanning L3-4 and L4-5, and 18 hybrid procedures (anterior lumbar interbody fusion) at L5-S1 and TDR at L4-5 (17) or L3-4 (1). Operative time averaged 130 minutes, with mean blood loss of 60 mL and no intraoperative complications. Postoperative X-rays showed good device placement, with restoration of disc height, foraminal volume, and sagittal balance. All patients were up and walking within 12 hours of surgery, and all but 9 were discharged the next day (7 of those 9 were hybrid TDR–anterior lumbar interbody fusion cases). Postoperatively, 5 of 36 patients (13.8%) had psoas weakness and 3 of 36 (8.3%) had anterior thigh numbness, with both symptoms resolving within 2 weeks. Of the 36 patients, 4 (11%) had postoperative facet joint pain, all in hybrid cases. Visual analog scale pain scores and Oswestry Disability Index scores improved by 74.5% and 69.2%, respectively, from preoperatively to 3-year follow-up. Range of motion at 3 years postoperatively averaged 8.1°. Signals of heterotopic ossification were present in 5 patients (13.9%), and 2 patients (5.5%) were considered to have fusion after 36 months. Conclusions The clinical and radiographic results of a laterally placed TDR have shown maintenance of pain relief and functional improvement over a long-term follow-up period. The benefits of the lateral access—minimal morbidity, avoidance of mobilization of the great vessels, preservation of the anterior longitudinal ligament, biomechanically stable orientation, and broader revision options—promote a new option for motion-preservation procedures.

Marchi, Luis; Oliveira, Leonardo; Coutinho, Etevaldo; Pimenta, Luiz

2012-01-01

364

Large diameter femoral head uncemented total hip replacement to treat fractured neck of femur.  

PubMed

The aim of this study was to investigate the use of large diameter head THR to treat fractured neck of femur, and to demonstrate if this conferred greater stability. Forty-six independent, mentally alert patients with displaced intracapsular fractures underwent THR. Mean age was 72.1 years. Outcome measures were dislocation, reoperation/revision rate, Oxford hip score (OHS), EuroQol (EQ-5D) and residential status. At mean follow-up (13.5 months) there were no dislocations. Reoperation, revision and infection rate were all 0%. Two patients died (4.3%). Mean pre-injury and postoperative OHS were 12.1 and 17.6, respectively. Mean pre-injury and postoperative EQ-5D index scores were 0.97 and 0.83, respectively. Mean postoperative walking distance was 2.5miles. There were no changes in residential status. This is the first published series using 36-mm diameter metal-on-metal THR for the treatment of fractured neck of femur. We have demonstrated that it affords patients excellent stability with no recorded dislocations. PMID:19464681

Barnett, A J; Burston, B J; Atwal, N; Gillespie, G; Omari, A M; Squires, B

2009-07-01

365

Total knee arthroplasty in elderly osteoporotic patients.  

PubMed

Often in daily practice the choice of a prosthesis does not rise out of considerations about literature evidences, but it seems to be related to the personal experience and "surgical philosophy" of surgeon. The choice of prosthesis in total joint replacement is usually justified by biological and mechanical parameters that the surgeon considers before surgery. Osteoporosis is a disease characterized by a reduced bone mass and a degeneration of the bone tissue; it leads to bone fragility, so to a higher risk of fractures. Bone resistance, as all the changes in the microarchitecture of the bone tissue, is linked to bone density. Because of the bone density variation and/or the changes in the bone micro-architecture, as the bone strength decreases, the risk of fractures increases. It is important to understand all the factors taking part in both normal and abnormal bone remodelling. Osteoporosis does not imply a concrete bone loss, but a change of the bone micro-architecture itself. In these cases the choice of the patient and implant design are very important. In the period between March 1997-July 2002, we implanted 100 consecutive TKA (total knee arthroplasty) Genesis II in 97 subjects (79 female); mean age was 77.1 years old. All TKA were performed because of primary osteoarthritis of the knee. All patients had complete pain relief and excellent knee score. The surgical and medical complications were in accordance with the published literature. We must consider all existing medical conditions, the state of the knee and local needs of the elderly patient. Thus, within these limits, the total knee can improve the ability of patients to manage the activities of daily living and improve their quality of life. PMID:21970933

Spinarelli, Antonio; Petrera, Massimo; Vicenti, Giovanni; Pesce, Vito; Patella, Vittorio

2011-04-01

366

Intraday Variability in total and polarized intensity  

NASA Astrophysics Data System (ADS)

The phenomenon of Intraday Variability (IDV) is the rapid flux density variations of blazars over large range of radio frequencies. The characteristic variability time scale ranges from half an hour to a few days. The peak-to-trough variability amplitude is typically between a few percents and a few tens of percent in total intensity, however it can be as high as 50% to 100% in polarized intensity. Using causality and the common light-travel time argument, the variability time scales translate into source sizes on the µas scale and consequently into brightness temperatures in the range of 1015 - 1021 K. These values are far in excess of the inverse Compton-limit brightness temperature. Relativistic boosting with high Doppler factors (>> 50) would be required to reduce these brightness temperatures to the inverse Compton-limit. However, such high Doppler factors were not observed in kinetic studies of the relativistic jets of blazars. The source-extrinsic interpretation of IDV however, attributes the rapid amplitude variations to interstellar scintillation (ISS) caused by the intervening ionized interstellar medium of the Milky Way. In this interpretation, the above mentioned extreme brightness temperatures are avoided. In the context of this propagation theory, the different variability patterns in total and linearly polarized flux density are explained by the existence of differently polarized sub-components in the source. The (soon-to-be-launched) second generation orbiting radio antenna, ASTRO-G will be able to observe polarization, moreover it will be possible to calibrate the measurements via observing close-by polarized sources. The radio interferometric array consisting of the orbiting antenna and ground-based radio antennas will provide sub-mas scale resolution. Thus, it will be possible to observe these polarized sub-components. Several aspects of total intensity and polarization variability will be demonstrated on an ex-ample IDV source, J1128+592.

Gabanyi, Krisztina Eva; Krichbaum, Thomas; Marchili, Nicola

367

Early reimplantation for open total talar extrusion.  

PubMed

PURPOSE. To review outcome of early reimplantation for open total talar extrusion in 7 patients. METHODS. Medical records of 5 men and 2 women aged 19 to 53 years who underwent reimplantation for open total talar extrusion within 6 hours after road traffic accident (n= 6) or industrial injury (n=1) were reviewed. The talus was first irrigated with 9 to 10 litres of saline solution, followed by 10% povidone iodine. It was then reduced after thorough debridement and fixed with tension band wiring or external fixation. Ankle mobilisation exercises were started at week 6 and full weight bearing at week 14. Outcome was assessed using the American Foot And Ankle Society score. RESULTS. After a mean follow-up of 31.9 (range, 24-46) months, the mean American Foot and Ankle Society score was 81, and the mean dorsiflexion-plantar flexion arc was 36.9º (range, 25º-45º). All patients were able to walk with a balanced, unaided gait with mild-to-moderate pain (n=3) or pain-free (n=4). No patient developed deep infection or instability. Three patients developed avascular necrosis of the talus; restriction of motion was moderate at the ankle joint and severe at the subtalar joint. None of these 3 patients opted for revision surgery, as the pain was tolerable and did not limit their daily activities, but their condition was expected to deteriorate with time. CONCLUSION. Early reimplantation is recommended for open total talar extrusion, as it restores (to some extent) hind foot mechanics, heel height, and bone stock for activities of daily living and future reconstructive options. PMID:25550007

Mohindra, M; Gogna, P; Thora, A; Tiwari, A; Singla, R; Mahindra, P

2014-12-01

368

Totally cystic schwannoma of the lumbar spine.  

PubMed

A schwannoma is a benign tumor arising from a schwann cell and occurs mainly in the nerve sheath in the intradural extramedullary region. Schwannomas have been well described as occurring in the lumbar spine, but total cystic degeneration of schwannomas is rarely reported. The authors describe the clinical and radiographic evaluations and treatment of a rare case of an intraextradural totally cystic schwannoma on the lumbar spine.Two patients reported a history of 6 to 12 months of pain accompanied by weakness in the lower extremities. On examination, 1 patient had bilateral lower-extremity muscle strength graded at 4/5, and magnetic resonance imaging revealed a cystic schwannoma (1.5 × 2.0 cm in the sagittal dimension) at L2-L3. The other patient had a right lower-extremity muscle strength graded at 3/5, and magnetic resonance imaging revealed a cystic schwannoma (2.0 × 3.0 cm in the sagittal dimension) at L4-L5. The patients underwent operative treatment, and the tumors were completely removed, as were the filum terminale adhered to the tumor. Pedicle screws were used to maintain stability of the lumbar spine. Gross examination of the tumors showed yellowish-white soft contents. Histologic examination confirmed that they were benign totally cystic schwannomas. Postoperatively, the patients' neurologic symptoms completely resolved.Cystic schwannomas can be diagnosed using preoperative magnetic resonance imaging. The filum terminale cut off the tumor walls did not cause the clinical symptoms in the 2 patients. PMID:23672923

Wu, Desheng; Ba, Zhaoyu; Huang, Yufeng; Zhao, Weidong; Shen, Bin; Kan, Heng

2013-05-01

369

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

370

Imaging of total colonic Hirschsprung disease  

Microsoft Academic Search

Background  Hirschsprung disease (HD) is a functional obstruction of the bowel caused by the absence of intrinsic enteric ganglion cells.\\u000a The diagnosis of total colonic HD (TCHD) based on contrast enemas is difficult in newborns because radiological findings vary.\\u000a \\u000a \\u000a \\u000a Objective  To evaluate the radiographic and contrast enema findings in patients with pathologically proven TCHD.\\u000a \\u000a \\u000a \\u000a Materials and methods  From 1966 to 2007, 17 records

Enno Stranzinger; Michael A. DiPietro; Daniel H. Teitelbaum; Peter J. Strouse

2008-01-01

371

Total Pelvic Exenteration for Gynecologic Malignancies  

PubMed Central

Total pelvic exenteration (PE) is a radical operation, involving en bloc resection of pelvic organs, including reproductive structures, bladder, and rectosigmoid. In gynecologic oncology, it is most commonly indicated for the treatment of advanced primary or locally recurrent cancer. Careful patient selection and counseling are of paramount importance when considering someone for PE. Part of the evaluation process includes comprehensive assessment to exclude unresectable or metastatic disease. PE can be curative for carefully selected patients with gynecologic cancers. Major complications can be seen in as many as 50% of patients undergoing PE, underscoring the need to carefully discuss risks and benefits of this procedure with patients considering exenterative surgery. PMID:22720150

Diver, Elisabeth J.; Rauh-Hain, J. Alejandro; del Carmen, Marcela G.

2012-01-01

372

Total synthesis of ramonanins?a-d.  

PubMed

The first total synthesis of the ramonanin family of lignan natural products is described. The short synthesis involves a 2,5-diaryl-3,4-dimethylene tetrahydrofuran intermediate, which participates in an unexpectedly facile Diels-Alder dimerization, generating all four natural products. Insights into the reactivity and stereoselectivity of the key dimerization are provided through computational studies employing B3LYP/6-31G(d) and M06-2X/6-31G(d) model chemistries. PMID:25510556

Harvey, Ross S; Mackay, Emily G; Roger, Lukas; Paddon-Row, Michael N; Sherburn, Michael S; Lawrence, Andrew L

2015-02-01

373

Cervical total disk replacement: complications and avoidance.  

PubMed

Anterior cervical diskectomy and fusion for neurologic deficits, radicular arm pain, and neck pain refractory to conservative management are successful. The approach and procedure were first described in 1955 and have become the anterior cervical standard of care for orthopedic surgeons and neurosurgeons. Advancements and innovations have addressed disease processes of the cervical spine with motion-preserving technology. The possibility of obtaining anterior cervical decompression while maintaining adjacent segment motion led to the advent of cervical total disk replacement. The Food and Drug Administration has approved 3 cervical devices with other investigational device exemption trials under way. PMID:22082633

Salari, Behnam; McAfee, Paul C

2012-01-01

374

Total synthesis of aphadilactones A-D.  

PubMed

The first total synthesis of aphadilactones A-D, diastereomeric natural products recently isolated from the Meliaceae plant Aphanamixis grandifolia by Yue and co-workers, which possess an unprecedented carbon skeleton, has been achieved. The synthesis features a catalytic asymmetric hetero-Diels-Alder reaction to form the dihydropyran ring, concurrent installation of the lactone and furan moieties via a tandem acid-catalyzed acetal cleavage, oxidation, and cyclization process, and an intermolecular Diels-Alder reaction to forge the target products. PMID:24959931

Yin, Jian-Peng; Gu, Min; Li, Ying; Nan, Fa-Jun

2014-07-01

375

Surgical approaches in total knee arthroplasty  

PubMed Central

Total knee replacement surgery begins with correct planning of both the incision and the exposure of the joint. Indeed, these are factors that are just as crucial to an optimal outcome as choosing the right implant, positioning the components, and balancing the ligaments. While it is true that the standard incision and arthrotomy (with which we are most familiar) will, in most primary implant cases, provide adequate joint exposure, it is also true that cases characterized by certain conditions, such as previous cutaneous incisions, a stiff knee or patella baja, present specific skin and exposure problems that need to be recognized, planned for and overcome.

SANNA, MARCO; SANNA, CRISTINA; CAPUTO, FRANCESCO; PIU, GIUSEPPE; SALVI, MASSIMILIANO

2013-01-01

376

Dual mobility in total hip arthroplasty.  

PubMed

Dual-mobility articulations have shown promising results. Postoperative instability remains the most common reason for revision of a total hip arthroplasty (THA). Dual-mobility cups have been shown to decrease the rate of dislocation in primary THA and have been used to treat and prevent instability in revision THA. Greater range of motion and a greater head-to-neck ratio and a greater jump distance are achieved, resulting in a lower risk of instability. Concerns with dual-mobility cups include wear and intraprosthetic dislocation. Specific design modifications have aimed to improve cup fixation and decrease polyethylene wear and the risks of intraprosthetic dislocation. PMID:24267202

Plummer, Darren R; Haughom, Bryan D; Della Valle, Craig J

2014-01-01

377

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

378

Lightcone reference for total gravitational energy  

E-print Network

We give an explicit expression for gravitational energy, written solely in terms of physical spacetime geometry, which in suitable limits agrees with the total Arnowitt-Deser-Misner and Trautman-Bondi-Sachs energies for asymptotically flat spacetimes and with the Abbot-Deser energy for asymptotically anti-de Sitter spacetimes. Our expression is a boundary value of the standard gravitational Hamiltonian. Moreover, although it stands alone as such, we derive the expression by picking the zero-point of energy via a ``lightcone reference.''

S. R. Lau

1999-03-10

379

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

380

Revision of the Sheehan total knee arthroplasty.  

PubMed

The use of the Sheehan knee prosthesis extended from 1971 to 2002. It incorporated a semi-constrained hinge with intra-medullary stems cemented into the femur and tibia. While some authors have reported excellent short-term results, others have reported revision rates of up to 31% at 5--10 years. The aim of this study was to review the senior author's experience in revising these arthroplasties. We review 54 Sheehan total knee replacements and discuss the difficulties encountered during first and subsequent revisions and the often-complex reconstruction techniques used to overcome these. PMID:15965689

Hurson, C; Boran, S; Synnott, K; Powell, O; Quinlan, W

2005-08-01

381

Total-variation regularization with bound constraints  

SciTech Connect

We present a new algorithm for bound-constrained total-variation (TV) regularization that in comparison with its predecessors is simple, fast, and flexible. We use a splitting approach to decouple TV minimization from enforcing the constraints. Consequently, existing TV solvers can be employed with minimal alteration. This also makes the approach straightforward to generalize to any situation where TV can be applied. We consider deblurring of images with Gaussian or salt-and-pepper noise, as well as Abel inversion of radiographs with Poisson noise. We incorporate previous iterative reweighting algorithms to solve the TV portion.

Chartrand, Rick [Los Alamos National Laboratory; Wohlberg, Brendt [Los Alamos National Laboratory

2009-01-01

382

Gas extrusion in natural products total synthesis.  

PubMed

The thermodynamic driving force from the release of a gaseous molecule drives a broad range of synthetic transformations. This review focuses on gas expulsion in key reactions within natural products total syntheses, selected from the past two decades. The highlighted examples survey transformations that generate sulfur dioxide, carbon dioxide, carbonyl sulfide, or nitrogen through polar, radical, pericyclic, photochemical, or organometallic mechanisms. Of particular interest are applications wherein the gas extrusion enables formation of a synthetically challenging motif, such as an unusually hindered or strained bond. PMID:22940671

Jiang, Xuefeng; Shi, Lei; Liu, Hui; Khan, Akbar H; Chen, Jason S

2012-11-14

383

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

384

Rare fracture of a total hip replacement.  

PubMed

Material fractures in the femoral part of total hip replacements, a late complication, are usually observed in the shaft. In our case, a fatigue fracture of the ball-neck weld occurred 8 1/2 years after implantation of the prosthesis because of insufficient weld depth. Additional negative factors proved to be varus implantation and overloading of the prosthesis due to obesity. The weld represented a point of low resistance. Even if major traumatic events are responsible for the fracture or loosening of an endoprosthesis, overloading (i.e., multiple "microtrauma") is also an important contributing factor. PMID:6870507

Aldinger, G; Mitzkat, K

1983-01-01

385

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...

386

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

387

38 CFR 3.340 - Total and permanent total ratings and unemployability.  

Code of Federal Regulations, 2012 CFR

...temporary exacerbations or acute infectious diseases except where specifically prescribed...permanent total disability. Diseases and injuries of long standing...of any incapacity from acute infectious disease, accident, or...

2012-07-01

388

38 CFR 3.340 - Total and permanent total ratings and unemployability.  

Code of Federal Regulations, 2011 CFR

...temporary exacerbations or acute infectious diseases except where specifically prescribed...permanent total disability. Diseases and injuries of long standing...of any incapacity from acute infectious disease, accident, or...

2011-07-01

389

38 CFR 3.340 - Total and permanent total ratings and unemployability.  

Code of Federal Regulations, 2014 CFR

...temporary exacerbations or acute infectious diseases except where specifically prescribed...permanent total disability. Diseases and injuries of long standing...of any incapacity from acute infectious disease, accident, or...

2014-07-01

390

38 CFR 3.340 - Total and permanent total ratings and unemployability.  

Code of Federal Regulations, 2013 CFR

...temporary exacerbations or acute infectious diseases except where specifically prescribed...permanent total disability. Diseases and injuries of long standing...of any incapacity from acute infectious disease, accident, or...

2013-07-01

391

38 CFR 3.340 - Total and permanent total ratings and unemployability.  

Code of Federal Regulations, 2010 CFR

...temporary exacerbations or acute infectious diseases except where specifically prescribed...permanent total disability. Diseases and injuries of long standing...of any incapacity from acute infectious disease, accident, or...

2010-07-01

392

Clinical and radiographic results of the total condylar III and constrained condylar total knee arthroplasty  

Microsoft Academic Search

The Total Condylar III (Johnson and Johnson, Braintree, MA) and Constrained Condylar (Zimmer, Warsaw, IN) knee prostheses are nonlinked, semi-constrained prosthetic alternatives to rigid or rotating hinge prostheses for use in complex knee reconstructions. Forty-six Total Condylar III or Constrained Condylar prostheses were implanted with cement in 36 patients and followed for a mean of 5 years (range, 2–9 years).

Paul F. Lachiewicz; Stephen P. Falatyn

1996-01-01

393

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

394

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

395

Dual mobility cups in total hip arthroplasty.  

PubMed

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

2014-07-18

396

Particle-enhanced total internal reflectance fluorescence®  

NASA Astrophysics Data System (ADS)

This paper presents work toward a retrofit of an acaTMIV Discrete Clinical Analyzer (E. I. du Pont de Nemours and Company, Wilmington, DE) with a Particle Enhanced Total Internal Reflection Fluorescence technology. The DuPont acaTM line of instruments was designed to perform highly accurate unit dose clinical chemistry assays. Introduction of a Total Reflectance Fluorescence optics into an acaTMIV could provide capability to perform highly sensitive homogeneous immunoassays. Sensitivity and precision depended upon uniform immobilization of immunoglobulins or immunogens, representing examples of specific binding partners, onto an ionomeric material, acting as both solid support and wall material of the disposable reagent units called the `pack'. This study examines the uniformity of antibody coating onto various types of tough and flexible optical polymeric films including those made from the DuPont SurlynTM and NucrelTM polymers. A number of coating processes will also be described. Bioanalytical tools were developed to determine uniformity, quantity, and activity of antibody coated onto the `pack' film, thus allowing for optimization of polymer film type and process of antibody coating.

Chu, Victor P.; Zoha, Steven J.; Davis, Jim; Chance, Suzette

1995-04-01

397

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

398

Total hip replacement in renal transplant patients.  

PubMed

Of 1197 renal transplant recipients on the Oxford Transplant Programme, 25 (2%) needed arthroplasties for painful osteonecrosis of the hip. Nine of them had bilateral operations, giving a total of 34 primary total hip replacements (THR). The mean time from onset of symptoms to THR was 2.4 years and from transplantation to THR 5.1 years. The mean follow-up was 5.1 (1 to 14) years. THR relieved the pain in all the patients, but survival analysis indicated a lower survival rate than is usual for primary THR. There were eight major complications. One graft-related problem, early acute tubular necrosis, resolved rapidly after immediate treatment. One patient developed deep infection at 3.5 years after THR which settled with conservative treatment. Five hips developed aseptic loosening requiring revision arthroplasty at a mean of 8.8 years' follow-up. One patient had a non-fatal pulmonary embolism. THR is the treatment of choice for patients with painful osteonecrosis of the hip after renal transplant, but has higher rates of both early and late complications. Surgery should be performed in close association with a renal transplant unit. PMID:7706352

Deo, S; Gibbons, C L; Emerton, M; Simpson, A H

1995-03-01

399

Helical tomotherapy for total lymphoid irradiation.  

PubMed

Total lymphoid irradiation is employed in the preparative regimens for allogeneic bone marrow and solid organ transplantation, solid organ transplant rejection, and chronic graft-versus-host disease. Linear accelerator-based radiotherapy, typically involving opposed anteroposterior and posteroanterior beams, has been commonly used; however, extended source-to-skin patient setup and/or field matching are required, and all organs within the beam coverage receive the entire prescribed dose. Megavoltage helical tomotherapy represents a technological advance in terms of both treatment delivery and patient positioning. The continuously rotating multileaf collimated fan beam allows highly conformal coverage of complex target geometries, in turn allowing avoidance of radiosensitive adjacent organs. In addition, the megavoltage computed tomographic scans allow potentially more accurate, targetbased setup verification. The present case report describes tomotherapy-based total lymphoid irradiation in an adult patient with late-onset cardiac transplant rejection. Treatment planning allowed dose minimization to the spinal cord, kidneys, intestinal compartment, and lungs. The patient tolerated treatment well without acute adverse effects, and he is now in early follow-up. PMID:19132495

McCutchen, Kathryn W; Watkins, John M; Eberts, Paul; Terwilliger, Lacy E; Ashenafi, Michael S; Jenrette, Joseph M

2008-12-01

400

Solar Total Energy Project final test report  

SciTech Connect

The Solar Total Energy Project (STEP), a cooperative effort between the United States Department of Energy (DOE) and Georgia Power Company (GPC) located at Shenandoah, Georgia, has undergone several design modifications based on experience from previous operations and test programs. The experiences encountered were discussed in detail in the Solar Total Energy Project Summary Report'' completed in 1987 for DOE. Most of the proposed changes discussed in this report were installed and tested in 1987 as part of two 15-day test programs (SNL Contract No. 06-3049). However, several of the suggested changes were not completed before 1988. These plant modifications include a new distributed control system for the balance of plant (BOP), a fiber a optical communications ring for the field control system, and new control configuration reflecting the new operational procedures caused by the plant modifications. These modifications were tested during a non-consecutive day test, and a 60-day field test conducted during the autumn of 1989. These test were partially funded by SNL under Contract No. 42-4859, dated June 22, 1989. Results of these tests and preliminary analysis are presented in this test summary report. 9 refs., 19 figs., 7 tabs.

Nelson, R.F.; Abney, L.O.; Towner, M.L. (Georgia Power Co., Shenandoah, GA (USA))

1990-09-01

401

[Total ankle arthroplasty for rheumatoid arthritis].  

PubMed

Modern second generation total ankle arthroplasty is now a serious alternative to ankle fusion in patients with rheumatoid arthritis after careful assessment of the indications. The midterm results with 10-year survival rates between 70% and 90% and the possible revision for implant exchange or arthrodesis are the reasons for the increasing importance of ankle arthroplasty. Patients with rheumatoid arthritis in particular with generally lower physical requirements can expect a pain-free function of the operated ankle for 8-10 years. In comparison to fusion ankle arthroplasty allows a significantly faster remobilization and reserves the correction capabilities of the ankle. Arthrodesis remains a valuable therapeutic alternative for severe bony destruction and instability as well as a possible fallback for failure of arthroplasty. PMID:21691912

Schill, S; Wetzel, R

2011-07-01

402

Total Anomalous Pulmonary Venous Return in Siblings  

PubMed Central

Total anomalous pulmonary venous return (TAPVR) is a rare and critical congenital vascular anomaly that requires an early operation. However, initial symptoms of TAPVR may be non-specific, and cardiovascular findings may be minimal. The heart may not be enlarged and there is often no cardiac murmur. Without cardiac murmur, these symptoms are similar to those of respiratory distress syndrome in newborns. Therefore, a high degree of suspicion and an early diagnosis of TAPVR are important. This condition generally occurs without a family history and has a low recurrence rate, but several familial cases, including siblings, have been reported worldwide. Additionally, several chromosomal or gene abnormalities associated with TAPVR have been reported. In the case presented here, two brothers with a 6-year age gap were diagnosed with TAPVR. Surgery was performed without cardiac or neurological complications. This is the first report on TAPVR in siblings in Korea. PMID:25580197

Kim, Ho-Sung; Jeong, Kumi; Cho, Hwa-Jin; Choi, Woo-Yeon; Choi, Young Earl; Ma, Jae Sook

2014-01-01

403

A Catalytic Asymmetric Total Synthesis of (-)-Perophoramidine.  

PubMed

We report a catalytic asymmetric total synthesis of the ascidian natural product perophoramidine. The synthesis employs a molybdenum-catalyzed asymmetric allylic alkylation of an oxindole nucleophile and a monosubstituted allylic electrophile as a key asymmetric step. The enantioenriched oxindole product from this transformation contains vicinal quaternary and tertiary stereocenters, and is obtained in high yield along with high levels of regio-, diastereo-, and enantioselectivity. To install the second quaternary stereocenter in the target, the route utilizes a novel regio- and diastereoselective allylation of a cyclic imino ether to deliver an allylated imino ether product in near quantitative yield and with complete regio- and diastereocontrol. Oxidative cleavage and reductive amination are used as final steps to access the natural product. PMID:25485074

Trost, B M; Osipov, M; Krüger, S; Zhang, Y

2015-01-01

404

Progressive Decoherence and Total Environmental Disentanglement  

E-print Network

The simple stationary decoherence of a two-state quantum system is discussed from a new viewpoint of environmental entanglement. My work emphasizes that an unconditional local state must totally be disentangled from the rest of the universe. It has been known for long that the loss of coherence within the given local system is gradual. Also the quantum correlations between the local system and the rest of the universe are being destroyed gradually. I show that, differently from local decoherence, the process of environmental disentanglement may terminate in finite time. The time of perfect disentanglement turns out to be on the decoherence time scale, and in a simple case we determine the exact value of it.

Lajos Diosi

2003-01-19

405

Total chemical management in photographic processing  

USGS Publications Warehouse

The mission of the U. S. Geological Survey's Earth Resources Observation Systems (EROS) Data Center is to produce high-quality photographs of the earth taken from aircraft and Landsat satellite. In order to meet the criteria of producing research-quality photographs, while at the same time meeting strict environmental restrictions, a total photographic chemical management system was installed. This involved a three-part operation consisting of the design of a modern chemical analysis laboratory, the implementation of a chemical regeneration system, and the installation of a waste treatment system, including in-plant pretreatment and outside secondary waste treatment. Over the last ten years the result of this program has yielded high-quality photographs while saving approximately 30,000 per year and meeting all Environmental Protection Agency (EPA) restrictions.

Luden, Charles; Schultz, Ronald

1985-01-01

406

Totally Hip Software, Inc.: WebPainter  

NSDL National Science Digital Library

Web authors in search of a high-quality tool for creating GIF animations should consider WebPainter by Totally Hip Software. Animated GIFs are viewable with most browsers, and are an easy way to spice up a Web site. WebPainter includes excellent bitmap drawing and animation tools, including an "onion skin" feature that allows users to draw a new animation frame while seeing a lightened version of the previous frame underneath. Pricing information is available at the site. An evaluation version of both the Mac and Windows 95/NT versions of WebPainter, which allows users save the first five frames of animation, is available for download. WebPainter is an excellent product for Web authors who would like to create animated graphics.

407

UPRE method for total variation parameter selection  

SciTech Connect

Total Variation (TV) Regularization is an important method for solving a wide variety of inverse problems in image processing. In order to optimize the reconstructed image, it is important to choose the optimal regularization parameter. The Unbiased Predictive Risk Estimator (UPRE) has been shown to give a very good estimate of this parameter for Tikhonov Regularization. In this paper we propose an approach to extend UPRE method to the TV problem. However, applying the extended UPRE is impractical in the case of inverse problems such as de blurring, due to the large scale of the associated linear problem. We also propose an approach to reducing the large scale problem to a small problem, significantly reducing computational requirements while providing a good approximation to the original problem.

Wohlberg, Brendt [Los Alamos National Laboratory; Lin, Youzuo [Los Alamos National Laboratory

2008-01-01

408

Total synthesis of branimycin: an evolutionary approach.  

PubMed

The first total synthesis of the macrolactone antibiotic branimycin (4) has been described. The key disconnection leads to a cis-dehydrodecalone core and a polyketide side chain which are connected via organometallic addition. The dehydrodecalone core was targeted via altogether five different approaches featuring various kinds of chiral elements and ring-closing methodology. In the end the most successful method starting from diepoxynaphthalene 109 was chosen to carry on with the synthesis. Thus the oxygen functions and carbon appendages were introduced via organometallic desymmetrization reactions to generate epoxy ketone 107, to which vinyl iodide 11 was added after conversion into the organolithium species. The synthesis was completed by introducing the ester side chain via Michael addition and subsequent macrolactonization. PMID:22764044

Enev, Valentin S; Felzmann, Wolfgang; Gromov, Alexey; Marchart, Stefan; Mulzer, Johann

2012-07-27

409

Total synthesis of the Daphniphyllum alkaloid daphenylline  

NASA Astrophysics Data System (ADS)

The Daphniphyllum alkaloids are a large class of natural products isolated from a genus of evergreen plants widely used in Chinese herbal medicine. They display a remarkable range of biological activities, including anticancer, antioxidant, and vasorelaxation properties as well as elevation of nerve growth factor. Daphenylline is a structurally unique member among the predominately aliphatic Daphniphyllum alkaloids, and contains a tetrasubstituted arene moiety mounted on a sterically compact hexacyclic scaffold. Herein, we describe the first total synthesis of daphenylline. A gold-catalysed 6-exo-dig cyclization reaction and a subsequent intramolecular Michael addition reaction, inspired by Dixon's seminal work, were exploited to construct the bridged 6,6,5-tricyclic motif of the natural product at an early stage, and the aromatic moiety was forged through a photoinduced olefin isomerization/6?-electrocyclization cascade followed by an oxidative aromatization process.

Lu, Zhaoyong; Li, Yong; Deng, Jun; Li, Ang

2013-08-01

410

NASA total quality management 1989 accomplishments report  

NASA Technical Reports Server (NTRS)

NASA and contractor employees achieved many notable improvements in 1989. The highlights of those improvements, described in this seventh annual Accomplishments Report, demonstrate that the people who support NASA's activities are getting more involved in quality and continuous improvement efforts. Their gains solidly support NASA's and this Nation's goal to remain a leader in space exploration and in world-wide market competition, and, when communicated to others through avenues such as this report, foster improvement efforts across government and industry. The principles in practice which led to these process refinements are important cultural elements to any organization's productivity and quality efforts. The categories in this report reflect NASA principles set forth in the 1980's and are more commonly known today as Total Quality Management (TQM): 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.

Tai, Betty P. (editor); Stewart, Lynne M. (editor)

1990-01-01

411

Total synthesis of alkaloid 205B.  

PubMed

Concise and highly stereocontrolled total syntheses of racemic and enantiopure frog alkaloid 205B (1) were accomplished in 11 steps from 4-methoxypyridines 6 and 7 in overall yields of 8 and 8%, respectively. The assembly of the core of the natural product relies on a stereoselective Tsuji-Trost allylic amination reaction and a ring-closing metathesis. The synthesis features the use of an N-acylpyridinium salt reaction to introduce the first stereocenter and an unprecedented trifluoroacetic anhydride-mediated addition of an allylstannane to a vinylogous amide with complete facial selectivity. Deoxygenation of the C4 ketone proved difficult but was accomplished via a modified Barton-McCombie reaction in the presence of a catalytic amount of diphenyl diselenide. PMID:25180567

Tsukanov, Sergey V; Comins, Daniel L

2014-10-01

412

Total endograft replacement of aortic arch  

PubMed Central

Total endovascular replacement of the aortic arch is a complex procedure that is often favoured when the pathology anatomy precludes a standard median sternotomy. Here we present the case of endograft repair in a 79 year old male with 6.5 cm arch aneurysm and 5.4 cm descending thoracoabdominal aneurysm. Following bilateral carotid-subclavian bypasses, a long 7 Fr sheath was advanced into the descending aorta through the common iliac artery purse string. A double curved long Lunderquist wire was guided to deep within the left ventricle, and the endograft carefully advanced over the wire. The graft was radiologically orientated, and deployed under asystolic conditions. Retrograde cannulation of the branches were accomplished, with carotid sheath placed into the branches followed by bridging stents. The graft delivery system was then removed. This approach obviates the need for a sternotomy, cumbersome extra-anatomic debranching, and hypothermic circulatory arrest. PMID:23977607

Neequaye, Simon

2013-01-01

413

Revision of total hip arthroplasty in octogenarians.  

PubMed

Twenty-seven revision total hip arthroplasties were performed in patients who were at least eighty years old. The average duration of follow-up was five years. There were no perioperative deaths, and only 11 per cent (three) of the patients had a major complication; all of the complications resolved. The only re-revision was the placement of an extended lip-liner for the treatment of recurrent dislocation. Of the twenty-five patients who were alive at the time of the most recent follow-up or who had been survived by a family member who could be interviewed, twenty-one (84 per cent) said that the operation had improved function, twenty-three (92 per cent) had less pain, and twenty-two (88 per cent) were satisfied with the result. PMID:7713976

Ballard, W T; Callaghan, J J; Johnston, R C

1995-04-01

414

A Catalytic Asymmetric Total Synthesis of (?)-Perophoramidine†  

PubMed Central

We report a catalytic asymmetric total synthesis of the ascidian natural product perophoramidine. The synthesis employs a molybdenum-catalyzed asymmetric allylic alkylation of an oxindole nucleophile and a monosubstituted allylic electrophile as a key asymmetric step. The enantioenriched oxindole product from this transformation contains vicinal quaternary and tertiary stereocenters, and is obtained in high yield along with high levels of regio-, diastereo-, and enantioselectivity. To install the second quaternary stereocenter in the target, the route utilizes a novel regio- and diastereoselective allylation of a cyclic imino ether to deliver an allylated imino ether product in near quantitative yield and with complete regio- and diastereocontrol. Oxidative cleavage and reductive amination are used as final steps to access the natural product. PMID:25485074

Osipov, M.; Krüger, S.; Zhang, Y.

2014-01-01

415

[Sir John Charnley and total hip arthroplasty].  

PubMed

Sir John Charnley (1911-1982), pioneer of the total hip prosthesis, saved countless elderly people from immobility. During the Second World War he assisted Dudley Buxton, orthopaedic surgeon to the British armed forces in the Middle East, in developing new instruments and splints. After the war he first studied healing of bone fractures and the role of compression, and then completely dedicated himself to arthroplasty of the hip. Through countless experiments he found the optimal diameter for the head of the stainless steel prosthesis as well as the optimal polymer for the socket; he also advocated tight cementing of the shaft into the femur. Sir John Charnley received the Lasker Award in 1974 and was knighted in 1977. PMID:21939571

Burgers, Paul T P W; van Gijn, Jan

2011-01-01

416

Total pressure averaging in pulsating flows  

NASA Technical Reports Server (NTRS)

A number of total-pressure tubes were tested in a non-steady flow generator in which the fraction of period that pressure is a maximum is approximately 0.8, thereby simulating turbomachine-type flow conditions. Most of the tubes indicated a pressure which was higher than the true average. Organ-pipe resonance which further increased the indicated pressure was encountered within the tubes at discrete frequencies. There was no obvious combination of tube diameter, length, and/or geometry variation used in the tests which resulted in negligible averaging error. A pneumatic-type probe was found to measure true average pressure, and is suggested as a comparison instrument to determine whether nonlinear averaging effects are serious in unknown pulsation profiles. The experiments were performed at a pressure level of 1 bar, for Mach number up to near 1, and frequencies up to 3 kHz.

Krause, L. N.; Dudzinski, T. J.; Johnson, R. C.

1972-01-01

417

Total-pressure averaging in pulsating flows.  

NASA Technical Reports Server (NTRS)

A number of total-pressure tubes were tested in a nonsteady flow generator in which the fraction of period that pressure is a maximum is approximately 0.8, thereby simulating turbomachine-type flow conditions. Most of the tubes indicated a pressure which was higher than the true average. Organ-pipe resonance which further increased the indicated pressure was encountered with the tubes at discrete frequencies. There was no obvious combination of tube diameter, length, and/or geometry variation used in the tests which resulted in negligible averaging error. A pneumatic-type probe was found to measure true average pressure and is suggested as a comparison instrument to determine whether nonlinear averaging effects are serious in unknown pulsation profiles.

Krause, L. N.; Dudzinski, T. J.; Johnson, R. C.

1972-01-01

418

21 CFR 872.3940 - Total temporomandibular joint prosthesis.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Total temporomandibular joint prosthesis. 872.3940 Section 872...872.3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...

2011-04-01

419

21 CFR 872.3940 - Total temporomandibular joint prosthesis.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Total temporomandibular joint prosthesis. 872.3940 Section 872...872.3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...

2012-04-01

420

21 CFR 872.3940 - Total temporomandibular joint prosthesis.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Total temporomandibular joint prosthesis. 872.3940 Section 872...872.3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...

2014-04-01

421

Computer Integrated Revision Total Hip Replacement Surgery: Preliminary Report  

E-print Network

Computer Integrated Revision Total Hip Replacement Surgery: Preliminary Report Leo Joskowicz1, and cement machining. Keywords: computer-assisted surgery, orthopaedics, revision total hip replacement in revision total hip replacement surgery (RTHR). In RTHR surgery, a failing orthopaedic hip implant

Taubin, Gabriel

422

21 CFR 862.1635 - Total protein test system.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Total protein test system. 862.1635 Section 862...Chemistry Test Systems § 862.1635 Total protein test system. (a) Identification. A total protein test system is a device intended to...

2013-04-01

423

21 CFR 862.1635 - Total protein test system.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Total protein test system. 862.1635 Section 862...Chemistry Test Systems § 862.1635 Total protein test system. (a) Identification. A total protein test system is a device intended to...

2012-04-01

424

21 CFR 862.1635 - Total protein test system.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Total protein test system. 862.1635 Section 862...Chemistry Test Systems § 862.1635 Total protein test system. (a) Identification. A total protein test system is a device intended to...

2010-04-01

425

21 CFR 862.1635 - Total protein test system.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Total protein test system. 862.1635 Section 862...Chemistry Test Systems § 862.1635 Total protein test system. (a) Identification. A total protein test system is a device intended to...

2011-04-01

426

21 CFR 872.3940 - Total temporomandibular joint prosthesis.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Total temporomandibular joint prosthesis. 872.3940...Devices § 872.3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a...

2010-04-01

427

Concerns with modularity in total hip arthroplasty.  

PubMed

Modularity is being diversified in total hip prostheses to increase surgical latitude in optimizing implant fixation and adjusting hip biomechanics. However, several problems have been clearly identified with implant modularity. First generation metal-backed acetabular components have shown deficiencies in the locking mechanism, the congruency and extent of polyethylene liner support, and polyethylene thickness, all of which have been implicated in accelerated polyethylene wear and failure. Evidence of screw motion against the metal backing, release of particulate material, and focal osteolysis have also been observed. At the head/neck junction evidence of corrosion and fretting has been documented with both similar-metal and mixed-metal taper combinations. Femoral prostheses with other sites of modularity present additional concerns with regard to mechanical integrity and generation of particulate debris by fretting. The modular junctions of three hip prostheses, the S-ROM, Infinity, and RMHS, were subjected to wet environment high cycle mechanical testing in a worst-case loading scenario. Preliminary results at relatively low loads up to three times body weight indicated gross stability of the modular junctions with evidence of minor fretting damage. Analysis of water solutions surrounding the modular junctions after ten to 20 million loading cycles yielded counts of one to three micron sized particles totalling several hundred thousand to several million. It is unknown what quantity of particulate material is sufficient to cause macrophage-mediated osteolysis or whether the debris from modular junctions can cause third-body wear of the articulating surfaces. Modular hip prostheses should be examined under stringent test conditions in order to characterize their fretting behavior and establish their mechanical limitations. PMID:8118986

Bobyn, J D; Tanzer, M; Krygier, J J; Dujovne, A R; Brooks, C E

1994-01-01

428

Enantioselective total syntheses of acylfulvene, irofulven, and the agelastatins  

E-print Network

I. Enantioselective Total Synthesis of (-)-Acylfulvene, and (-)-Irofulven We report the enantioselective total synthesis of (-)-acylfulvene and (-)-irofulven, which features metathesis reactions for the rapid assembly of ...

Siegel, Dustin S. (Dustin Scott), 1980-

2010-01-01

429

Total synthesis of Class II and Class III Galbulimima Alkaloids  

E-print Network

I. Total Synthesis of All Class III Galbulimima Alkaloids We describe the total synthesis of (+)- and (-)-galbulimima alkaloid 13, (-)-himgaline anad (-)-himbadine. The absolute stereochemistry of natural (-)-galbulimima ...

Tjandra, Meiliana

2010-01-01

430

Calibration of the Total Irradiance Monitor  

NASA Astrophysics Data System (ADS)

We present an overview of the calibrations of the Total Irradiance Monitor (TIM), a total solar irradiance (TSI) instrument designed to achieve a relative standard uncertainty (1 ? accuracy) of 100 parts per million (ppm) and a precision and long-term uncertainty of 10 ppm/year. This instrument is one of four on the Solar Radiation and Climate Experiment (SORCE, http://lasp.colorado.edu/sorce), a satellite mission scheduled for launch in July of 2002. The TIM will report four TSI measurements daily, continuing a 22-year record of solar irradiance through SORCE's goal 5-year mission life. Precision detection of TSI by the TIM follows the basic concepts of electrical substitution radiometry, but employs state-of-the-art electronics and materials. The instrument uses four electrical substitution radiometers (ESRs), each behind a precision aperture, to measure TSI while providing instrument redundancy and sensor degradation detection. The absorptive cavities are used in pairs, one as the active sensor and the other providing a thermal reference. The black absorbing surfaces of diffuse nickel phosphorous (NiP) provide good thermal conductivity, robustness against hard radiation, and low intrinsic outgassing. A shutter modulates incident sunlight to the active ESR, while electrical heater power maintains constant cavity temperature despite the fluctuations in absorbed sunlight. Phase-sensitive detection of the electrical power supplied to the active cavity at the shutter frequency determines cavity absorption and hence TSI. Additionally, this DSP-controlled phase-sensitive detection and thermal control reduces sensitivity to thermal drifts and noise, enabling the instrument's high precision. The TIM's ability to achieve the desired relative standard uncertainty results from component-level calibrations and characterizations to better than 100 ppm. NIST measured the precision apertures to stated accuracies of 25 ppm. LASP measured the ESR reflectances at several wavelengths spanning the visible and near infrared, and selected the flight ESRs based on their low ( ~100 ppm) and stable reflectances. We have recorded the resistances of all ESR electrical leads to the needed 2 ppm uncertainty level. Additionally, we report on system-level measurements indicating instrument reproducibility and relative accuracy.

Kopp, G.; Lawrence, G.; Rottman, G.

2001-05-01

431

Total synthesis of (-)-cocaine and (-)-ferruginine.  

PubMed

Total synthesis of tropane alkaloids (-)-cocaine and (-)-ferruginine were accomplished in nine steps each and in 55% and 46% overall yields, respectively, starting from the known Betti base derivative (+)-(7aR,10R,12S)-10-(1H-benzotriazol-1-yl)-7a,8,9,10-tetrahydro-12-phenyl-12H-naphtho[1,2-e]pyrrolo[2,1-b][1,3]oxazine. In this novel route, RCM reaction and 1,3-dipolar cycloaddition were employed as key steps for the enantioselective construction of tropane skeleton and the regioselective introduction of 3-bromo-2-isoxazoline ring as masked cis-2,3-disubstituents. To obtain the desired precursor (2S,5R)-2-allyl-5-vinylpyrrolidine for RCM reaction, we developed a general and practical method for the preparation of enantiopure cis-2,5-disubstituted pyrrolidines bearing alkene- and/or alkyne-containing substituents. We also offered two highly efficient pathways for the conversion of the 3-bromo-2-isoxazoline ring into the desired cis-2,3-disubstituted groups in (-)-cocaine and (-)-ferruginine. PMID:21391709

Cheng, Guolin; Wang, Xinyan; Zhu, Rui; Shao, Changwei; Xu, Jimin; Hu, Yuefei

2011-04-15

432

Capillary electrophoresis for total glycosaminoglycan analysis.  

PubMed

A capillary zone electrophoresis-laser-induced fluorescence detection (CZE-LIF) method was developed for the simultaneous analysis of disaccharides derived from heparan sulfate, chondroitin sulfate/dermatan sulfate, hyaluronan, and keratan sulfate. Glycosaminoglycans (GAGs) were first depolymerized with the mixture of GAG lyases (heparinase I, II, III and chondroitinase ABC and chondroitinase AC II) and GAG endohydrolase (keratinase II) and the resulting disaccharides were derivatized by reductive amination with 2-aminoacridone. Nineteen fluorescently labeled disaccharides were separated using 50 mM phosphate buffer (pH 3.3) under reversed polarity at 25 kV. Using these conditions, all the disaccharides examined were baseline separated in less then 25 min. This CZE-LIF method gave good reproducibility for both migration time (?1.03% for intraday and ?4.4% for interday) and the peak area values (?5.6% for intra- and ?8.69% for interday). This CZE-LIF method was used for profiling and quantification of GAG derivative disaccharides in bovine cornea. The results show that the current CZE-LIF method offers fast, simple, sensitive, reproducible determination of disaccharides derived from total GAGs in a single run. PMID:24817364

Ucakturk, Ebru; Cai, Chao; Li, Lingyun; Li, Guoyun; Zhang, Fuming; Linhardt, Robert J

2014-07-01

433

SynCardia: the total artificial heart  

PubMed Central

The SynCardia total artificial heart (TAH) currently provides the most definitive option for patients with biventricular failure who are not candidates for isolated left ventricular (LV) assist device placement. The techniques for implantation are adaptable to almost all patients with advanced heart failure, including those with severe biventricular cardiomyopathy, complex congenital heart disease, failed LV assist devices, failed transplantations, and acquired structural heart defects that have failed or are not amenable to conventional surgical treatment. Over the years, the implantation technique has evolved in order to minimize the surgical invasiveness of the procedure, in anticipation of additional future surgery. Meticulous hemostasis with double layer sutures, use of Gore-Tex sheets around the TAH and the pericardial cavity, and use of tissue expanders to avoid contraction of pericardial cavity around the device are discussed in detail in the following report. Additionally, we will provide our experience with implantation of TAH in various challenging scenarios, such as patients with a small chest cavity, congenital heart defects, and simultaneous use of extracorporeal membrane oxygenation (ECMO). PMID:25512904

Anyanwu, Anelechi; Zucchetta, Fabio; Gerosa, Gino

2014-01-01

434

The Road to Total Earthquake Safety  

NASA Astrophysics Data System (ADS)

Cinna Lomnitz is possibly the most distinguished earthquake seismologist in all of Central and South America. Among many other credentials, Lomnitz has personally experienced the shaking and devastation that accompanied no fewer than five major earthquakes—Chile, 1939; Kern County, California, 1952; Chile, 1960; Caracas,Venezuela, 1967; and Mexico City, 1985. Thus he clearly has much to teach someone like myself, who has never even actually felt a real earthquake.What is this slim book? The Road to Total Earthquake Safety summarizes Lomnitz's May 1999 presentation at the Seventh Mallet-Milne Lecture, sponsored by the Society for Earthquake and Civil Engineering Dynamics. His arguments are motivated by the damage that occurred in three earthquakes—Mexico City, 1985; Loma Prieta, California, 1989; and Kobe, Japan, 1995. All three quakes occurred in regions where earthquakes are common. Yet in all three some of the worst damage occurred in structures located a significant distance from the epicenter and engineered specifically to resist earthquakes. Some of the damage also indicated that the structures failed because they had experienced considerable rotational or twisting motion. Clearly, Lomnitz argues, there must be fundamental flaws in the usually accepted models explaining how earthquakes generate strong motions, and how we should design resistant structures.

Frohlich, Cliff

435

The management of chronic total coronary occlusions.  

PubMed

Although recent consensus has clearly defined chronic total occlusions (CTO), attempted percutaneous coronary intervention (PCI) remains low. Histopathologically, CTOs are characterized by fibrous caps, varying degrees of plaques, and neovascularization, with both increasing with the age of the CTO. Multiple registries and studies show that successful PCI of CTOs can improve symptoms, left ventricular function, and mortality. There is overwhelming evidence that very low restenosis and reocclusion rates can be obtained with drug eluting stents after recanalization of CTOs. PCI should be considered the preferred initial revascularization modality in patients in whom a high procedural success rate may be anticipated. Novel techniques have greatly enhanced procedural success, and include ''parallel'' and ''seesaw'' wire techniques, balloon anchoring, subintimal tracking and reentry (STAR), retrograde approach, contralateral injection, and intravascular ultrasound (IVUS) guidance. Improvements in wire technology have largely been responsible for improved procedural success in PCI of CTO, while application of new technologies hold promise to significantly better outcomes. Magnetic resonance imaging (MRI) and multislice computed tomography (CT) are already employed in formulating treatment strategies and their role in the treatment of CTOs is likely to increase. PMID:18813187

Cuneo, A; Tebbe, U

2008-10-01

436

Autologous blood donation in total hip replacement.  

PubMed

The effectiveness of autologous blood donation in reducing the need for homologous transfusion was evaluated in a review of 529 consecutive total hip replacements (THR) from 1988 to 1992. The review was retrospective from 1988 to 1990 and prospective from 1991 to 1992. Since 1988 there have been 188 primary THR performed using autologous blood donation. In 1988-89, this represented 18% of all primary THR, in 1990 37% and in 1991-92 73%. This increase reflects a growing enthusiasm for the programme and a loosening of age restrictions. In 1991-92, 4% of autologous donors undergoing primary THR required homologous transfusions compared to 84% of non-autologous donors. Over the same period after revision THR, 36% of autologous donors required homologous transfusions compared to 100% of non-autologous donors. The participation rate of patients undergoing revision THR was 33%. The prospective part of the study in 1991-92 compared autologous and matched non-autologous patients. Blood loss, transfusion volumes and operating time were identical. The pre- and postoperative haemoglobin concentrations in the autologous group were lower by 15 and 10 g/L, respectively, after primary THR and by 10 g/L in both instances after revision THR. This was not reflected in a longer admission. PMID:7818416

Sharland, M G; Holman, P R

1995-01-01

437

Cementless revision for infected total hip replacements.  

PubMed

Our aim was to determine the success rate of repeated debridement and two-stage cementless revision arthroplasty according to the type of infected total hip replacement (THR). We enrolled 294 patients (294 hips) with an infected THR in the study. There were 222 men and 72 women with a mean age of 55.1 years (24.0 to 78.0). The rate of control of infection after the initial treatment and after repeated debridement and two-stage revisions was determined. The clinical (Harris hip score) and radiological results were evaluated. The mean follow-up was 10.4 years (5.0 to 14.0). The eventual rate of control of infection was 100.0% for early superficial post-operative infection, 98.4% for early deep post-operative infection, 98.5% for late chronic infection and 91.0% for acute haematogenous infection. Overall, 288 patients (98%) maintained a functioning THR at the latest follow-up. All the allografts appeared to be united and there were no failures. These techniques effectively controlled infection and maintained a functional THR with firm fixation in most patients. Repeated debridement and two-stage or repeated two-stage revisions further improved the rate of control of infection after the initial treatment and increased the likelihood of maintaining a functional THR. PMID:21196538

Kim, Y-H; Kim, J-S; Park, J-W; Joo, J-H

2011-01-01

438

Mortality after total hip replacement surgery  

PubMed Central

Total hip replacement causes a short-term increase in the risk of mortality. It is important to quantify this and to identify modifiable risk factors so that the risk of post-operative mortality can be minimised. We performed a systematic review and critical evaluation of the current literature on the topic. We identified 32 studies published over the last 10 years which provide either 30-day or 90-day mortality data. We estimate the pooled incidence of mortality during the first 30 and 90 days following hip replacement to be 0.30% (95% CI 0.22 to 0.38) and 0.65% (95% CI 0.50 to 0.81), respectively. We found strong evidence of a temporal trend towards reducing mortality rates despite increasingly co-morbid patients. The risk factors for early mortality most commonly identified are increasing age, male gender and co-morbid conditions, particularly cardiovascular disease. Cardiovascular complications appear to have overtaken fatal pulmonary emboli as the leading cause of death after hip replacement. Cite this article: Bone Joint Res 2014;3:175–82. PMID:24894596

Berstock, J. R.; Beswick, A. D.; Lenguerrand, E.; Whitehouse, M. R.; Blom, A. W.

2014-01-01

439

Process optimized minimally invasive total hip replacement  

PubMed Central

The purpose of this study was to analyse a new concept of using the the minimally invasive direct anterior approach (DAA) in total hip replacement (THR) in combination with the leg positioner (Rotex- Table) and a modified retractor system (Condor). We evaluated retrospectively the first 100 primary THR operated with the new concept between 2009 and 2010, regarding operation data, radiological and clinical outcome (HOOS). All surgeries were perfomed in a standardized operation technique including navigation. The average age of the patients was 68 years (37 to 92 years), with a mean BMI of 26.5 (17 to 43). The mean time of surgery was 80 min. (55 to 130 min). The blood loss showed an average of 511.5 mL (200 to 1000 mL). No intra-operative complications occurred. The postoperative complication rate was 6%. The HOOS increased from 43 points pre-operatively to 90 (max 100 points) 3 months after surgery. The radiological analysis showed an average cup inclination of 43° and a leg length discrepancy in a range of +/? 5 mm in 99%. The presented technique led to excellent clinic results, showed low complication rates and allowed correct implant positions although manpower was saved. PMID:22577504

Gebel, Philipp; Oszwald, Markus; Ishaque, Bernd; Ahmed, Gaffar; Blessing, Recha; Thorey, Fritz; Ottersbach, Andreas

2012-01-01

440

Patellar malalignment treatment in total knee arthroplasty  

PubMed Central

Summary The patella, with or without resurfacing, plays a fundamental role in the success of a total knee arthroplasty (TKA). Patellofemoral joint complications are due to problems related to the patient, to the surgical technique, or to the design of the components. Patellar tracking is influenced by several factors: a severe preoperative valgus, the presence of pre-existing patellofemoral dysplasia, the design of the femoral component, the surgical approach, the Q angle, the mechanical alignment of the limb, the tightness of the lateral retinaculum, the positioning of the patellar component in the proximal-distal and medial-lateral directions, the patella height, the patella (native or resurfaced) thickness, the size of the femoral and the tibial components, and the alignment and rotation of the components. Several factors are crucial to prevent patellar maltracking in TKA: the use of an anatomical femoral component, a meticulous surgical technique, careful dynamic intraoperative assessment of patellar tracking, and, if necessary, the achievement of an adequate lateral release.

Gasparini, Giorgio; Familiari, Filippo; Ranuccio, Francesco

2013-01-01

441

[Total trapezometacarpal prostheses: concepts and classification study].  

PubMed

This paper is an attempt to classify the different types of trapezio-metacarpal total prostheses according to their bio-mechanical principle and to compare the bio-mechanics of these prostheses to that of the normal trapeziometacarpal joint. The trapeziometacarpal joint has two approximate centres of rotation (one in the proximal metacarpal, one in the trapezium), two degrees of freedom and two arc of mobility about 70 degrees. The mechanical model of the trapeziometacarpal joint is a universal-joint called "cardan" with three constraint forces (one axial compression force, and two shear forces, radial and posterior) and one constraint moment around the longitudinal axis. The trapeziometacarpal prostheses may be classified in two main categories: the most frequently used are the "ball and socket" prostheses. Several prostheses, including the surface replacement prostheses have the mechanical characteristics of an universal joint (cardan). Ball and socket prostheses have one centre of rotation, 3 degrees of freedom, three constraint forces in three directions and no constraint moment when "cardan" or surface prostheses have two centres of rotation and 2 degrees of freedom; three constraint forces and one constraint moment. Trapeziometacarpal prostheses may also be classified according to their arc of mobility, or according to their mode of primary fixation (cemented, non-cemented), "press-fit", expansion and to their secondary fixation (hydroxyapatite). PMID:11291318

Comtet, J J; Rumelhart, C

2001-02-01

442

Stem torsion in total hip replacement  

PubMed Central

Background and purpose The clinical results of THR may be improved by correct femoral torsion. We evaluated the stem position by postoperative CT examination in 60 patients. Methods 60 patients requiring total hip arthroplasty were prospectively enrolled in this study. Minimally invasive THR was performed (anterior approach) in a lateral decubitus position and each patient underwent a postoperative CT examination. The position of the stem was evaluated by an independent external institution. Results Stem torsion ranged from –19° retrotorsion to 33° antetorsion. Normal antetorsion (i.e 10–15° according to Tönnis) was present in 5 of 60 patients, so the prevalence of abnormal stem antetorsion was 92% (95% CI: 82–97). We found a stem antetorsion outside the range of 0–25° in 21 of 60 hips. Women had a higher mean stem antetorsion (8.0° (SD 11)) than men (1.5° (SD 10)). Interpretation Postoperative stem antetorsion shows a high variability and is gender-related. We suggest precise assessment of stem antetorsion intraoperatively by means of computer navigation, preparing the femur first. In abnormal stem antetorsion, the cup position can be adjusted using a combined anteversion concept; alternatively, modular femoral components or stems with retroverted or anteverted necks (“retrostem”) could be used. PMID:20919811

2010-01-01

443

The (Almost) Unseen Total Eclipse of 1831  

NASA Astrophysics Data System (ADS)

The total eclipse of August 1831 began at sunrise in Australia, swept across the western South Pacific Ocean, and ended at sunset in the central South Pacific. As a result of the eclipse's path over mostly uninhabited ocean, the region's sparse European (British) population, and near-useless local predictions of the event at Hobart and Sydney in almanacs sold to the general public, almost no one witnessed its passage. In an attempt to document the eclipse, journals of naive observers - those having no access to a prediction - were examined. Thus far, the sole record is in the Pitcairn Island Register Book. Considering the Pitcairners' extreme isolation and the rather modest partial eclipse that occurred there, the entry is a surprising one; however, it can be explained in terms of events associated with their initial removal to Tahiti in March 1831 followed by their return home in June. Further, an authoritative means to identify any issues associated with eclipse predictions compiled for private-sector almanacs came in 1833 when sweeping changes in the British Nautical Almanac's section on eclipses were instituted.

Bartky, Ian R.

2008-03-01

444

Process optimized minimally invasive total hip replacement.  

PubMed

The purpose of this study was to analyse a new concept of using the the minimally invasive direct anterior approach (DAA) in total hip replacement (THR) in combination with the leg positioner (Rotex- Table) and a modified retractor system (Condor). We evaluated retrospectively the first 100 primary THR operated with the new concept between 2009 and 2010, regarding operation data, radiological and clinical outcome (HOOS). All surgeries were perfomed in a standardized operation technique including navigation. The average age of the patients was 68 years (37 to 92 years), with a mean BMI of 26.5 (17 to 43). The mean time of surgery was 80 min. (55 to 130 min). The blood loss showed an average of 511.5 mL (200 to 1000 mL). No intra-operative complications occurred. The postoperative complication rate was 6%. The HOOS increased from 43 points pre-operatively to 90 (max 100 points) 3 months after surgery. The radiological analysis showed an average cup inclination of 43° and a leg length discrepancy in a range of +/- 5 mm in 99%. The presented technique led to excellent clinic results, showed low complication rates and allowed correct implant positions although manpower was saved. PMID:22577504

Gebel, Philipp; Oszwald, Markus; Ishaque, Bernd; Ahmed, Gaffar; Blessing, Recha; Thorey, Fritz; Ottersbach, Andreas

2012-01-01

445

SynCardia: the total artificial heart.  

PubMed

The SynCardia total artificial heart (TAH) currently provides the most definitive option for patients with biventricular failure who are not candidates for isolated left ventricular (LV) assist device placement. The techniques for implantation are adaptable to almost all patients with advanced heart failure, including those with severe biventricular cardiomyopathy, complex congenital heart disease, failed LV assist devices, failed transplantations, and acquired structural heart defects that have failed or are not amenable to conventional surgical treatment. Over the years, the implantation technique has evolved in order to minimize the surgical invasiveness of the procedure, in anticipation of additional future surgery. Meticulous hemostasis with double layer sutures, use of Gore-Tex sheets around the TAH and the pericardial cavity, and use of tissue expanders to avoid contraction of pericardial cavity around the device are discussed in detail in the following report. Additionally, we will provide our experience with implantation of TAH in various challenging scenarios, such as patients with a small chest cavity, congenital heart defects, and simultaneous use of extracorporeal membrane oxygenation (ECMO). PMID:25512904

Torregrossa, Gianluca; Anyanwu, Anelechi; Zucchetta, Fabio; Gerosa, Gino

2014-11-01

446

Pain Management and Accelerated Rehabilitation for Total Hip and Total Knee Arthroplasty  

Microsoft Academic Search

Improved pain management techniques and accelerated rehabilitation programs are revolutionizing our patients' postoperative experience after total hip and knee arthroplasty. The process involves regional anesthesia with multimodal pain control using local periarticular injections in combination with enhanced patient education and accelerated rehabilitation provided by a dedicated team of surgeons, physicians, anesthesiologists, physician assistants, physical therapists, and social workers. With this

Amar S. Ranawat; Chitranjan S. Ranawat

2007-01-01

447

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

E-print Network

. Shoemaker, et al., Reverse Monte Carlo neutron scattering study of disordered crystalline materials neutron as function of r-range Large Model: Reverse Monte Carlo 20000 + atoms Fit X-ray and neutron F(Q), G(r) , Bragg@lanl.gov Research interests: Total scattering analysis, magnetism, multiferroic materials. Graham King HIPD Postdoc

Magee, Joseph W.

448

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

E-print Network

por Centros del nº de estudiantes que participan en Programas de Movilidad CENTRO EXTERNOS ( * ) PROPIOS ( ** ) TOTAL Fuente: Oficina de Relaciones Internacionales y Movilidad, a 10 de Octubre de 2014 Distribución de estudiantes externos según Centro de destino y Programa de Movilidad CENTRO SICUE (2) BECAS REP

Autonoma de Madrid, Universidad

449

Determining total phenolic content and total antioxidant capacity of loquat cultivars grown in Hatay  

PubMed Central

Several fruit characteristics of five loquat (Eriobotrya japonica (Thunb.) Lindl.) cultivars/selections grown in Dörtyol, Hatay, Turkey were investigated in 2008. The cultivars/selections included ‘Baduna 5’, Güzelyurt 1, ‘Hafif Çukurgöbek’, ‘Ottaviani,’ and Type 1. The characteristics evaluated included fruit weight, width, length, seed number and weight, flesh/seed ratio, total soluble solids (TSS), pH, acidity, total phenolic (TP) content, and total antioxidant capacity (TAC), determined by the ferric reducing antioxidant power (FRAP) assay. The analyses were conducted by three replicates, with 30 fruits in each replicate. The results indicated that there were significant differences among the cultivars, for all the traits tested. For example, ‘Hafif Çukurgöbek’ and ‘Ottaviani’ had smaller fruits than others, although ‘Hafif Çukurgöbek’ had heavier seeds. The flesh/seed ratio was the highest in Type 1, while ‘Hafif Çukurgöbek’ had the highest pH and high soluble solids. ‘Baduna 5’ and ‘Hafif Çukurgöbek’ had the highest acidity. The TP ranged from 129 (‘Baduna 5’) to 578 (‘Hafif Çukurgöbek’) mg gallic acid equivalent (GAE)/kg fresh fruit (fw). ‘Hafif Çukurgöbek’ also had the highest FRAP mean (12.1 mmol Trolox Equivalent (TE)/kg fw). The results suggest that loquat cultivars have a variable range of TP content and a relatively high total antioxidant capacity, which is crucial for human health. PMID:20548929

Polat, A. Aytekin; Çali?kan, O?uzhan; Serçe, Sedat; Saraço?lu, Onur; Kaya, Cemal; Özgen, Mustafa

2010-01-01

450

Soil Test P vs. Total P in Wisconsin Soils  

E-print Network

Soil Test P vs. Total P in Wisconsin Soils Larry G. Bundy & Laura W. Good Department of Soil Science University of Wisconsin-Madison #12;Introduction · Soil test P is often measured · Little information is available on total P content of soils · Why do we care about total P now? ­ Soil total P

Balser, Teri C.

451

Total Reward Stochastic Games and Sensitive Average Reward Strategies  

Microsoft Academic Search

In this paper, total reward stochastic games are surveyed. Total reward games are motivated as a refinement of average reward games. The total reward is defined as the limiting average of the partial sums of the stream of payoffs. It is shown that total reward games with finite state space are strategically equivalent to a class of average reward games

F. Thuijsman; O. J. Vrieze

1998-01-01

452

Quantification of total element concentrations in soils using total X-ray fluorescence spectroscopy (TXRF).  

PubMed

Total X-ray fluorescence spectroscopy (TXRF) determines concentrations of major and trace elements in multiple media. We developed and tested a method for the use of TXRF for direct quantification of total element concentrations in soils using an S2 PICOFOX™ spectrometer (Bruker AXS Microanalysis GmbH, Germany). We selected 15 contrasting soil samples from across sub-Saharan Africa for element analysis to calibrate the instrument against concentrations determined using the inductively coupled plasma-mass spectroscopy (ICP-MS) standard method. A consistent underestimation of element concentrations using TXRF compared to ICP-MS reference analysis occurred, indicating that spectrometer recalibration was required. Single-element recalibration improved the TXRF spectrometer's sensitivity curve. Subsequent analysis revealed that TXRF determined total element concentrations of Al, K, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Ga accurately (model efficacy/slope close to 1:1 line, and R(2)>0.80) over a wide range of soil samples. Other elements that could be estimated with an acceptable precision (R(2)>0.60) compared with ICP-MS although generally somewhat under- or overestimated were P, Ca, As, Rb, Sr, Y, Pr, Ta and Pb. Even after recalibration, compared to ICP-MS the TXRF spectrometer produced underestimations for elements Na, Mg, Ba, Ce, Hf, La, Nd, W and Sm and overestimations for elements Bi, Tl and Zr. We validated the degree of accuracy of the TXRF analytical method after recalibration using an independent set of 20 soil samples. We also tested the accuracy of the analysis using 2 multi-element standards as well as the method repeatability on replicate samples. The resulting total element concentration repeatability for all elements analyzed were within 10% coefficient of variability after the instrument recalibration except for Cd and Tl. Our findings demonstrate that TXRF could be used as a rapid screening tool for total element concentrations in soils assuming that sufficient calibration measures are followed. PMID:23831788

Towett, Erick K; Shepherd, Keith D; Cadisch, Georg

2013-10-01

453

Laparoscopic totally extraperitoneal repair without suprapubic port: comparison with conventional totally extraperitoneal repair  

PubMed Central

Purpose We have treated 24 patients through laparoscopic totally extraperitoneal (TEP) repair without suprapubic port by using reliability and reducing the invasiveness of two surgery. This study is aimed to assess the safety and feasibility of the TEP repair without suprapubic port compared to conventional TEP repair. Methods From September 2007 to 11 May 2010, we compared two groups that suffer from inguinal hernias. One is comprised of 24 patients who were treated without suprapubic port laparoscopic totally extraperitoneal repair (Group A), and the other is comprised of 100 patients who were treated with conventional laparoscopic totally extraperitoneal repair (Group B). Data regarding patient demographics (sex, age, site of hernia, and the type of hernia), operating time, postoperative hospital stay, the use of analgesics, and complications were prospectively collected. Results There was no significant difference noted between two groups in relation to sex, age, site, and the type of hernia. The mean operating time and postoperative hospital stay was longer for the Group B (62.9 minutes, 3.55 days) than for the Group A (59.0 minutes, 2.54 days) (P = 0.389, P < 0.001). Postoperative urinary retention, seroma, wound infection were respectively 4.2%, 8.3%, 0% in Group A, and 12.0%, 8.0%, 7% in group B. There was difference between the two groups, but not statistical significance. Group B used more analgesics than Group A (0.33 vs. 0.48), but it wasn't significant statistically (P = 0.234). Conclusion Although prospective randomized studies with long-term follow-up evaluation are needed to confirm our study between laparoscopic totally extraperitoneal repair without suprapubic-port and conventional laparoscopic totally extraperitoneal repair, our method have some advantages in postoperative pain, urinary retention, operating time, postoperative hospital stay, and cosmetic effect. PMID:22066055

Kwon, Ki-Hwak; Han, Won-Kon

2011-01-01

454

Periprosthetic Bone Remodelling in Total Knee Arthroplasty  

PubMed Central

ABSTRACT Introduction: The clinical studies have shown that the displacement of the prosthesis components, especially of the tibial one is higher during the first year, after which it reaches an equilibrum position compatible with a good long term functioning. This displacement takes place due to bone remodelling close to the implant secondary to different loading concentrations over different areas of bone. Material and Method: Our study implies a simulation on a computational model using the finite element analysis. The simulation started taking into account arbitrary points because of non-linear conditions of bone-prosthesis interface and it was iterative.. A hundred consecutive situations corresponding to intermediate bone remodelling phases have been calculated according to given loadings. Bone remodelling was appreciated as a function of time and bone density for each constitutive element of the computational model created by finite element method. For each constitutive element a medium value of stress during the walking cycle was applied. Results: Analyse of proximal epiphysis-prosthesis complex slices showed that bone density increase is maintained all over the stem in the immediately post-operative period. At 10 months, the moment considered to be the end of bone remodelling, areas with increased bone density are fewer and smaller. Meanwhile, their distribution with a concentration toward the internal compartment in the distal metaphysis is preserved. Conclusions: After the total knee arthroplasty the tibial bone suffered a process of remodelling adapted to the new stress conditions. This bone remodelling can influence, sometimes negatively, especially in the cases with tibial component varus malposition, the fixation, respectively the survival of the prosthesis. This process has been demonstrated both by clinical trials and by simulation, using the finite elements method of periprosthetic bone remodelling. PMID:25553127

GEORGEANU, Vlad; ATASIEI, Tudor; GRUIONU, Lucian

2014-01-01

455

Total lymphoid irradiation for multiple sclerosis  

SciTech Connect

Although chemical immunosuppression has been shown to benefit patients with chronic progressive multiple sclerosis (MS), it appears that chemotherapy has an appreciable oncogenic potential in patients with multiple sclerosis. Accordingly, we developed a modified total lymphoid irradiation (TLI) regimen designed to reduce toxicity and applied it to a randomized double blind trial of TLI or sham irradiation in MS. Standard TLI regimens were modified to reduce dose to 1,980 rad, lowering the superior mantle margin to midway between the thyroid cartilage and angle of the mandible (to avert xerostomia) and the lower margin of the mantle field to the inferior margin of L1 (to reduce gastrointestinal toxicity by dividing abdominal radiation between mantle and inverted Y), limiting spinal cord dose to 1,000 rad by custom-made spine blocks in the mantle and upper 2 cm of inverted Y fields, and also protecting the left kidney even if part of the spleen were shielded. Clinical efficacy was documented by the less frequent functional scale deterioration of 20 TLI treated patients with chronic progressive MS compared to to 20 sham-irradiated progressive MS patients after 12 months (16% versus 55%, p less than 0.03), 18 months (28% versus 63%, p less than 0.03), and 24 months (44% versus 74%, N.S.). Therapeutic benefit during 3 years follow-up was related to the reduction in lymphocyte count 3 months post-irradiation (p less than 0.02). Toxicity was generally mild and transient, with no instance of xerostomia, pericarditis, herpes zoster, or need to terminate treatment in TLI patients. However, menopause was induced in 2 patients and staphylococcal pneumonia in one.

Devereux, C.K.; Vidaver, R.; Hafstein, M.P.; Zito, G.; Troiano, R.; Dowling, P.C.; Cook, S.D.

1988-01-01

456

Preliminary total dose measurements on LDEF.  

PubMed

After spending nearly six years in Earth orbit twenty stacks consisting of radiation detectors and biological objects are now back on Earth. These stacks (Experiment A0015 Free Flyer Biostack) are part of the fifty seven science and technology experiments of the Long Duration Exposure Facility (LDEF) of NASA. The major objectives of the Free Flyer Biostack experiments are to investigate the biological effectiveness of single heavy ions of the cosmic radiation in various biological systems and to provide information about the spectral composition of the radiation field and the total dose received in the LDEF orbit. The Biostacks are mounted in two different locations of the LDEF. Up to three layers of Lithium fluoride thermoluminescence dosimeters (TLD) of different isotopic composition were located at different depths of some Biostacks. The preliminary analysis of the TLD yields maximum absorbed dose rates of 2.24 mGy day-1 behind 0.7 g cm-2 shielding and 1.17 mGy day-1 behind 12 g cm-2 shielding. A thermal neutron fluence of 1.7 n cm-2 s-1 is determined from the differences in absorbed dose for different isotopic mixtures of Lithium. The results of this experiment on LDEF are especially valuable and of high importance since LDEF stayed for about six years in the prospected orbit of the Space Station Freedom. There is no knowledge about the effectiveness of the space radiation in long-term spaceflights and the dosimetric data in this orbit are scarce. PMID:11537032

Reitz, G

1992-01-01

457

Future Bearing Surfaces in Total Hip Arthroplasty  

PubMed Central

One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements have been made with regard to fixation technique and implant quality. PMID:24605198

2014-01-01

458

Total synthesis of (+)-4,5-deoxyneodolabelline.  

PubMed

The first total synthesis of the marine dolabellane diterpene (+)-4,5-deoxyneodolabelline (1) has been accomplished. The highly efficient approach is characterized by the convergent assembly of dihydropyrans 2ab and cyclopentylsilanes 3ab. Allylic silane 3a was prepared from 2-methyl-2-cyclopentenone via a copper-catalyzed 1,4-addition followed by diastereoselective alkylation of the resulting enolate. A chemical resolution of racemic cyclopentanone 8 was effected by (S)-CBS-catalyzed borohydride reduction. Direct hydroxymethylation of the enantioenriched ketone 8 to form allylic alcohol 14 was achieved by a Stille palladium-catalyzed cross-coupling from the cyclopentenyl triflate 13. Treatment of the corresponding allylic phosphate 15 with trimethylsilylcopper reagent provided for displacement with allylic transposition yielding the exocyclic allylsilane 3a with excellent diastereoselectivity. Dihydropyrans 2a and 2b were prepared from optically pure acyclic acetals via ring-closing metathesis. Coupling of 3a and 2a or 2b via the carbon-Ferrier protocol gave trans-2,6-disubstituted dihydropyrans 30 and 35 with complete stereoselectivity. Vanadium-based pinacol coupling reactions were explored for closure of the medium-sized carbocycle to yield syn-diol 33. X-ray diffraction studies of the monobenzoate 34 have provided unambiguous stereochemical assignments. Substantial ring strain accounted for the lack of alkene products typical of reductive elimination using TiCl(3) and zinc-copper couple (McMurry) conditions leading to 37. Finally, the natural product 1 was obtained via Swern oxidation of the diol 37. PMID:12580611

Williams, David R; Heidebrecht, Richard W

2003-02-19

459

Improved results of primary total hip replacement  

PubMed Central

Background and purpose Over the past 20 years, several changes in treatment policy and treatment options have taken place regarding hip replacement. For this reason, we wanted to investigate the results after hip replacement in terms of revision rate, during a 21-year period among hip replacements reported to the Norwegian Arthroplasty Register. Methods 110,882 primary total hip replacements were reported to the Norwegian Arthroplasty Register from 1987 through 2007. Risk of revision during the time periods 1993–1997, 1998–2002, and 2003–2007 was compared to that of the reference period 1987–1992. Adjusted Cox regression analyses were performed to compare the risk of revision in different time periods and extended analyses were done to investigate revision within the first postoperative year and after the first year. Results There was an overall reduced risk of revision in the time periods 1993–1997, 1998–2002, and 2003–2007 compared to the reference period: RR = 0.81 (95% CI 0.77–0.86), 0.51 (CI 0.47–0.55), and 0.77 (CI 0.68–0.85), respectively. The improved results were due to a marked reduction in aseptic loosening of the femoral and acetabular components in all time periods and in all subgroups of prostheses. A change in the timing of revision took place, with more early revisions and fewer late revisions in the later time periods. Revision due to dislocation and infection increased over time. Interpretation The risk of revision decreased during the study period, due to fewer cases of aseptic loosening of prosthetic components. The best results were obtained with the use of cemented prostheses. Prevention of dislocation and infection should be a major goal in the future, as revision due to these causes increased during the study period. PMID:21110699

2010-01-01

460

Scaling properties of proton-nucleus total reaction cross sections  

E-print Network

We study the scaling properties of proton-nucleus total reaction cross sections for stable nuclei and propose an approximate expression in proportion to Z^{2/3}\\sigma_{pp}^{total} + N^{2/3} \\sigma_{pn}^{total}. Based on this expression, we can derive a relation that enables us to predict a total reaction cross section for any stable nucleus within 10% uncertainty at most, using the empirical value of the total reaction cross section of a given nucleus.

Badawy Abu-Ibrahim; Akihisa Kohama

2010-05-03

461

Antioxidant activity, total phenolic and total flavonoid contents of whole plant extracts Torilis leptophylla L  

PubMed Central

Background The aim of this study was to screen various solvent extracts of whole plant of Torilis leptophylla to display potent antioxidant activity in vitro and in vivo, total phenolic and flavonoid contents in order to find possible sources for future novel antioxidants in food and pharmaceutical formulations. Material and methods A detailed study was performed on the antioxidant activity of the methanol extract of whole plant of Torilis leptophylla (TLM) and its derived fractions {n-hexane (TLH), chloroform (TLC) ethyl acetate (TLE) n-butanol (TLB) and residual aqueous fraction (TLA)} by in vitro chemical analyses and carbon tetrachloride (CCl4) induced hepatic injuries (lipid peroxidation and glutathione contents) in male Sprague-Dawley rat. The total yield, total phenolic (TPC) and total flavonoid contents (TFC) of all the fractions were also determined. TLM was also subjected to preliminary phytochemical screening test for various constituents. Results The total phenolic contents (TPC) (121.9±3.1 mg GAE/g extract) of TLM while total flavonoid contents (TFC) of TLE (60.9 ±2.2 mg RTE/g extract) were found significantly higher as compared to other solvent fractions. Phytochemical screening of TLM revealed the presence of alkaloids, anthraquinones, cardiac glycosides, coumarins, flavonoids, saponins, phlobatannins, tannins and terpenoids. The EC50 values based on the DPPH (41.0±1 ?g/ml), ABTS (10.0±0.9 ?g/ml) and phosphomolybdate (10.7±2 ?g/ml) for TLB, hydroxyl radicals (8.0±1 ?g/ml) for TLC, superoxide radicals (57.0±0.3 ?g/ml) for TLM and hydrogen peroxide radicals (68.0±2 ?g/ml) for TLE were generally lower showing potential antioxidant properties. A significant but marginal positive correlation was found between TPC and EC50 values for DPPH, hydroxyl, phosphomolybdate and ABTS, whereas another weak and positive correlation was determined between TFC and EC50 values for superoxide anion and hydroxyl radicals. Results of in vivo experiment revealed that administration of CCl4 caused a significant increase in lipid peroxidation (TBARS) while decrease in GSH contents of liver. In contrast, TLM (200 mg/kg bw) and silymarin (50 mg/kg bw) co-treatment effectively prevented these alterations and maintained the antioxidant status. Conclusion Data from present results revealed that Torilis leptophylla act as an antioxidant agent due to its free radical scavenging and cytoprotective activity. PMID:23153304

2012-01-01

462

Total synthesis of myxovirescin A1.  

PubMed

A convergent total synthesis of the antibiotic macrolide myxovirescin A1 (1) is described that is largely based on reagent- and catalyst-controlled transformations. This includes a highly regioselective Negishi reaction of dibromo-alkene 48 with an alkynylzinc reagent, and a palladium catalyzed alkyl-Suzuki coupling of the resulting enyne derivative 12 with the 9-BBN-adduct derived from alkene 61. The latter was obtained via an asymmetric hydrogenation of the chlorinated beta-ketoester 49 and an anti-selective oxyallylation of the functionalized aldehyde 53 as the key steps. The preparation of the bis-borylated allyl-donor 57 used in the oxyallylation step, however, required careful optimization and led to important insights into the nature of the classical hydroborating agent "di(isopinocampheyl)borane (Ipc2BH)". It was unambiguously shown by X-ray crystallography that in the solid state this compound is dimeric, but it is prone to undergo an essentially quantitative mono-deborylation when dissolved in CH2Cl2 or benzene; its composition in ethereal solvents is even more complex as evident from 11B NMR data. Product 71 derived from 12 and 61 was elaborated into the enyne-yne derivative 75, which served as the substrate for an exquisitely selective ring closing alkyne metathesis reaction (RCAM) catalyzed by the molybdenum tris-amido complex 20 activated in situ with CH2Cl2. The resulting cyclic enyne 76 was subjected to a ruthenium catalyzed trans-hydrosilylation/proto-desilylation tandem. Although [Cp*Ru(MeCN)3]PF6 had previously been recommended as catalyst of choice for trans-hydrosilylation reactions of internal alkynes, this complex failed to afford the desired product, whereas its sterically less hindered congener [CpRu(MeCN)3]PF6 permitted the reaction to be performed in appreciable yield, but at the expense of a lower stereoselectivity. AgF-mediated proto-desilylation of the isomeric silanes 79 and 80 followed by cleavage of the remaining acetal protecting groups afforded myxovirescin A1 and its hitherto unknown 14Z-isomer 81, respectively. PMID:17768720

Fürstner, Alois; Bonnekessel, Melanie; Blank, Jarred T; Radkowski, Karin; Seidel, Günter; Lacombe, Fabrice; Gabor, Barbara; Mynott, Richard

2007-01-01

463

Topical tranexamic acid reduces blood loss and transfusion rates in total hip and total knee arthroplasty.  

PubMed

The objective of this study was to determine if tranexamic acid (TXA) applied topically reduced postoperative bleeding and transfusion rates after primary total hip arthroplasty (THA) and primary total knee arthroplasty (TKA). Two hundred and ninety consecutive patients from a single surgeon were enrolled. In TKA, TXA solution was injected into the knee after closure of the arthrotomy. In THA, the joint was bathed in TXA solution at three points during the procedure. In both THA and TKA the TXA solution was at a concentration of 3 g TXA per 100 mL saline. The mean blood loss was significantly higher in the non-TXA patients in both TKA and THA groups. Postoperative transfusions decreased dramatically with TXA, dropping from 10% to 0%, and from 15% to 1%, in the TKA and THA groups, respectively. Topical application of TXA significantly reduces postoperative blood loss and transfusion risk in TKA and THA. PMID:23886406

Konig, Gerhardt; Hamlin, Brian R; Waters, Jonathan H

2013-10-01

464

Topical tranexamic acid reduces blood loss and transfusion rates in total hip and total knee arthroplasty  

PubMed Central

The objective of this study was to determine if tranexamic acid (TXA) applied topically reduced postoperative bleeding and transfusion rates after primary total hip arthroplasty (THA) and primary total knee arthroplasty (TKA). Two hundred and ninety consecutive patients from a single surgeon were enrolled. In TKA, TXA solution was injected into the knee after closure of the arthrotomy. In THA, the joint was bathed in TXA solution at three points during the procedure. In both THA and TKA the TXA solution was at a concentration of 3gm TXA per 100mL saline. The mean blood loss was significantly higher in the non-TXA patients in both TKA and THA groups. Postoperative transfusions decreased dramatically with TXA, dropping from 10% to 0%, and from 15% to 1%, in the TKA and THA groups, respectively. Topical application of TXA significantly reduces postoperative blood loss and transfusion risk in TKA and THA. PMID:23886406

Konig, Gerhardt; Hamlin, Brian R.; Waters, Jonathan H.

2013-01-01

465

T.Q.M.: Total Quality Management or total quackery and mismanagement  

SciTech Connect

The concept of total quality management (TQM) is outlined. The basic idea of TQM is that quality products and services will lead a company to greater financial success than will mass quantities of inferior products. The following topics are outlined: standard labs and TQM;TQM benefits to be gained by standard labs; TQM at standard labs is quality improvement system (QIS), TQM, reduces of attitude. QIS team leader training agenda; and the safety connection.

Stallard, T.F.

1996-12-31

466

21 CFR 862.1470 - Lipid (total) test system.  

Code of Federal Regulations, 2013 CFR

...is a device intended to measure total lipids (fats or fat-like substances) in serum and plasma. Lipid (total) measurements are used in...treatment of various diseases involving lipid metabolism and atherosclerosis. (b)...

2013-04-01

467

21 CFR 862.1470 - Lipid (total) test system.  

Code of Federal Regulations, 2012 CFR

...is a device intended to measure total lipids (fats or fat-like substances) in serum and plasma. Lipid (total) measurements are used in...treatment of various diseases involving lipid metabolism and atherosclerosis. (b)...

2012-04-01

468

10 CFR 603.520 - Reasonableness of total project funding.  

Code of Federal Regulations, 2010 CFR

...Section 603.520 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Pre-Award Business Evaluation Total Funding § 603.520 Reasonableness of total project funding. In...

2010-01-01

469

Recommended Amounts of Total vegetables including beans and peas  

Cancer.gov

Recommended Amounts of Total vegetables including beans and peas Table B2. Total vegetables including beans and peas: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) %

470

Recommended Amounts of Total protein foods excluding beans and peas  

Cancer.gov

Recommended Amounts of Total protein foods excluding beans and peas Table B11. Total protein foods excluding beans and peas: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation

471

20 CFR 410.412 - “Total disability” defined.  

Code of Federal Regulations, 2010 CFR

... Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, TITLE IV-BLACK LUNG BENEFITS (1969- ) Total Disability or Death Due to Pneumoconiosis § 410.412 “