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1

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

PubMed Central

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

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

2008-01-01

2

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

PubMed Central

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

S?balle, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken

2014-01-01

3

Short-term results with the Zweymueller-SL metal-on-metal total hip arthroplasty  

Microsoft Academic Search

. In a prospective study we followed 266 consecutive patients who received 350 Zweymueller-SL uncemented total hip replacements with metal-on-metal articulation for osteoarthritis. Mean follow-up was 52 (range 37-92) months. Patient age at the time of surgery was 55±9 (25-70) years. Pre-operative Harris score of 45±19 was increased post-operatively to 96±4. Pre-operative invalidity was significantly improved post-operatively (P Résumé. étude

Panagiotis Korovessis; Georgios Petsinis; Maria Repanti; Zisis Papazisis; Panagiotis Iliopoulos; Panagiotis N. Soucacos

2002-01-01

4

Corrosion on the Acetabular Liner Taper from Retrieved Modular Metal-on-Metal Total Hip Replacements.  

PubMed

Eight retrieved metal-on-metal total hip replacements displayed corrosion damage along the cobalt-chromium alloy liner taper junction with the Ti alloy acetabular shell. Scanning electron microscopy indicated the primary mechanism of corrosion to be grain boundary and associated crevice corrosion, which was likely accelerated through mechanical micromotion and galvanic corrosion resulting from dissimilar alloys. Coordinate measurements revealed up to 4.3mm(3) of the cobalt-chromium alloy taper surface was removed due to corrosion, which is comparable to previous reports of corrosion damage on head-neck tapers. The acetabular liner-shell taper appears to be an additional source of metal corrosion products in modular total hip replacements. Patients with these prostheses should be closely monitored for signs of adverse reaction towards corrosion by-products. PMID:24997654

Gascoyne, Trevor C; Dyrkacz, Richard M; Turgeon, Thomas R; Burnell, Colin D; Wyss, Urs P; Brandt, Jan-M

2014-10-01

5

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.

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

2014-01-01

6

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

7

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

PubMed Central

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

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

2014-01-01

8

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

PubMed

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

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

2014-11-18

9

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 ”g/L (range 3.1-45) and the median serum Chromium was 5.8 ”g/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

2014-09-26

10

Large diameter metal-on-metal total hip arthroplasty for Crowe IV developmental dysplasia of the hip.  

PubMed

The short-term results of middle-aged patients with severe developmental dysplasia of the hip treated with subtrochanteric femoral shortening and cementless large diameter metal-on-metal total hip arthroplasty were retrospectively evaluated. Clinical and radiological results of 15 hips of 13 patients with Crowe IV developmental dysplasia of the hip were enrolled in this study. The average follow-up period was 49 months (36-62 months). The average age of patients at the time of surgery was 45.5 years (range, 36-65 years). Radiographs were evaluated for component position, subsidence, loosening, and osteolysis. Intraoperatively, two patients had a small proximal femoral shaft split that was held with a cable wire. The average preoperative Harris hip score was 58; at 3 years, 82. Trendelenburg sign was negative in 11 hips at the last assessment. Loosening, subsidence, infection, dislocation, hypersensitivity and neurovascular complications were not observed. One hip had to be revised 1 year after surgery because of nonunion at the osteotomy site. Our study shows that large diameter metal-on-metal total hip arthroplasty, incorporating subtrochanteric femoral shortening, decreases dislocation rate and provides excellent results for the completely dislocated hip. PMID:20041376

Parmaksizoglu, Atilla Sancar; Ozkaya, Ufuk; Bilgili, Fuat; Basilgan, Seckin; Kabukcuoglu, Yavuz

2009-01-01

11

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

12

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

13

Few adverse reactions to metal on metal articulation in total hip arthroplasty in a review study on 358 consecutive cases with 1 to 5 years follow-up.  

PubMed

The aim of the present study was to determine the frequency of adverse reaction to metal on metal total hip arthroplasty using a M2a-38 articulation and a Magnum articulation, (Biomet Warsaw, Indiana).All patients who had received a Metal on Metal bearing prosthesis, in two centres in Copenhagen, were asked to complete a questionnaire about groin pain. Patients with self-reported groin pain, 68/314, underwent a physical examination and had Co and Cr ion levels measured in full blood samples. Fifty patients also had a CT scan performed.The present study found one patient with bilateral arthroplasty, who had an adverse reaction on one side. In addition the study showed that females had higher values of Co and Cr, and that younger patient reported groin pain more often.The conclusion of this study is that the number of adverse reactions is low, despite the time of observation being relatively short, no high frequency of adverse reactions to this prosthesis is expected. PMID:22930667

Stürup, Jens; Dahl, Line B; Jensen, Karl-Erik; Larsen, Anne-Birgitte; Gebuhr, Peter

2012-01-01

14

Few Adverse Reactions to Metal on Metal Articulation in Total Hip Arthroplasty in a Review Study on 358 Consecutive Cases with 1 to 5 Years Follow-Up  

PubMed Central

The aim of the present study was to determine the frequency of adverse reaction to metal on metal total hip arthroplasty using a M2a-38 articulation and a Magnum articulation, (Biomet Warsaw, Indiana). All patients who had received a Metal on Metal bearing prosthesis, in two centres in Copenhagen, were asked to complete a questionnaire about groin pain. Patients with self-reported groin pain, 68/314, underwent a physical examination and had Co and Cr ion levels measured in full blood samples. Fifty patients also had a CT scan performed. The present study found one patient with bilateral arthroplasty, who had an adverse reaction on one side. In addition the study showed that females had higher values of Co and Cr, and that younger patient reported groin pain more often. The conclusion of this study is that the number of adverse reactions is low, despite the time of observation being relatively short, no high frequency of adverse reactions to this prosthesis is expected. PMID:22930667

Sturup, Jens; Dahl, Line B; Jensen, Karl-Erik; Larsen, Anne-Birgitte; Gebuhr, Peter

2012-01-01

15

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

16

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

PubMed

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

2012-03-01

17

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

18

Necrotic pseudotumor caused by a metal-on-metal total hip prosthesis: imaging characteristics on (18)F-FDG PET/CT and correlative imaging.  

PubMed

Necrotic pseudotumor is a complication of metal-on-metal arthroplasty that has been reported with increasing frequency in the last 5 years. It is believed to be the result of a hypersensitivity reaction to metal ions such as nickel, cobalt, or chromium that are released in large quantities from these prostheses. The imaging appearance of a necrotic pseudotumor caused by a metal-on-metal prosthesis, on (18)F-FDG PET/CT or (99m)Tc-MDP bone scan has not been previously described in the literature. Our case demonstrates that a necrotic pseudotumor can be detected incidentally in oncologic patients referred for an (18)F-FDG PET/CT or a (99m)Tc-MDP bone scan, and recognizing this process is vital in preventing further tissue necrosis and patient morbidity, as the offending prosthesis must be promptly removed. The imaging characteristics of a necrotic pseudotumor on PET/CT and bone scan may also mimic a malignant process such as a necrotic sarcoma, and can represent a potential pitfall leading to a false positive diagnosis in an oncologic patient. PMID:21318272

Makis, William; Rush, Christopher; Abikhzer, Gad

2011-06-01

19

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

PubMed Central

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

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

2013-01-01

20

Strong association between smoking and the risk of revision in a cohort study of patients with metal-on-metal total hip arthroplasty.  

PubMed

Thus far the ability to predict who will develop early failure following the insertion of a metal-on-metal (MoM) bearing has been very limited. Our objective was to assess the effect of smoking on failure rates in patients with MoM bearing, compared with patients with ceramic-on-polyethylene (CoP) bearing. From a prospective hospital-based registry we included all primary THAs operated upon between 1/2001 and 12/2011 with MoM or CoP bearings of the same cup design and head size (28?mm). We compared revision rates through 10/2013 classified by smoking status and type of bearing. We included 1,964 patients (median age 71, 57% women), 663 with MoM and 1,301 with CoP bearing. Mean follow-up was 6.9 years (range 1.8-12.8). Revisions were required for 56 THAs. In patients with MoM bearing the adjusted incidence rate of revision among ever-smokers was four times greater than among never-smokers (95% CI 1.4-10.9). Among those with CoP bearing, the rate ratio was only 1.3 (95% CI 0.6-2.5). We found a strong association between smoking and increased failure of MoM THAs. In contrast, the association was weak for patients with CoP bearing. Smoking might be a trigger or an effect amplifier for adverse reactions to metal debris from MoM bearings. PMID:24615914

Lübbeke, Anne; Rothman, Kenneth J; Garavaglia, Guido; Barea, Christophe; Christofilopoulos, Panayiotis; Stern, Richard; Hoffmeyer, Pierre

2014-06-01

21

Metal-on-metal hip joint tribology.  

PubMed

The basic tribological features of metal-on-metal total hip replacements have been reviewed to facilitate an understanding of the engineering science underpinning the renaissance of these hard-on-hard joints. Metal-on-polymer hip replacements operate in the boundary lubrication regime, thus leading to the design guidance to reduce the femoral head diameter as much as is feasible to minimize frictional torque and volumetric wear. This explains why the gold-standard implant of this form from the past half-century had a diameter of only 22.225 mm (7/8 in). Metal-on-metal implants can operate in the mild mixed lubrication regime in which much of the applied load is supported by elastohydrodynamic films. Correct tribological design leads to remarkably low steady state wear rates. Promotion of the most effective elastohydrodynamic films calls for the largest possible head diameters and the smallest clearances that can reasonably be adopted, consistent with fine surface finishes, good sphericity and minimal structural elastic deformation of the cup on its foundations. This guidance, which is opposite in form to that developed for metal-on-polymer joints, is equally valid for solid (monolithic) metallic heads on metallic femoral stems and surface replacement femoral shells. Laboratory measurements of friction and wear in metal-on-metal joints have confirmed their potential to achieve a very mild form of mixed lubrication. The key lies in the generation of effective elastohydrodynamic lubricating films of adequate thickness compared with the composite roughness of the head and cup. The calculation of the film thickness is by no means easy, but the full procedure is outlined and the use of an empirical formula that displays good agreement with calculations based upon the full numerical solutions is explained. The representation of the lambda ratio, lambda, embracing both film thickness and composite roughness, is described. PMID:16669380

Dowson, D; Jin, Z M

2006-02-01

22

A retrospective comparative study of mortality and causes of death among patients with metal-on-metal and metal-on-polyethylene total hip prostheses in primary osteoarthritis after a long-term follow-up  

PubMed Central

Background All patients with total hip arthroplasty (THA), especially those with metal-on-metal (MM) THA, are exposed to metallic particles and ions, which may cause total or site-specific mortality. We analyzed the causes of total and site-specific mortality among a cohort of patients with MM and with metal-on-polyethylene (MP) THA after a long follow-up time. Methods Standardized mortality ratios (SMR) of total and site-specific causes of death were calculated for 579 patients with MM (McKee-Farrar) and 1585 patients with MP (Brunswik, Lubinus) THA for primary osteoarthritis. Results Mean follow-up time was 17.9 years for patients with MM and 16.7 years for patients with MP. Overall SMR was 0.95 for the MM cohort and 0.90 for the MP cohort, as compared to the normal population. Both cohorts showed significantly decreased mortality for the first decade postoperatively, equal mortality over the next 10 years, and significantly increased mortality after 20 years. Patients with MM THA had higher cancer mortality (SMR 1.01) than those with MP THA (SMR 0.66) during the first 20 years postoperatively, but not thereafter. Conclusion Both MM and MP prostheses are safe based on total and site-specific mortality of recipients during the first 20 postoperative years in comparison with the general population. PMID:20416065

2010-01-01

23

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

PubMed Central

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

2014-01-01

24

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

25

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

Microsoft Academic Search

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

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

2006-01-01

26

Effect of metallic nanoparticles on the biotribocorrosion behaviour of Metal-on-Metal hip prostheses  

Microsoft Academic Search

Concerns of polyethylene wear debris induced osteolysis has been partially responsible for the renewed interest in the second generation Metal-on-Metal (MoM) hip replacements as an alternative to widely used Metal-on-Polyethylene (MoP) joint prostheses. The total wear loss from MoM is much less than from MoP. However, the number of nano-sized wear particles from MoM is more than a hundred times

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

2009-01-01

27

Short-term results of the M 2a-taper metal-on-metal articulation  

Microsoft Academic Search

A polyethylene-free, metal-on-metal acetabular system (M2a-taper [Biomet, Inc., Warsaw, IN]) was designed in an effort to improve total hip arthroplasty (THA) longevity. Minimum 2-year follow-up results involving 72 polyethylene liner THAs and 78 metal liner THAs from a multicenter, randomized, controlled, investigational device exemption study are reported. Mean Harris hip scores of 95.54 (polyethylene liner group) and 95.23 (metal liner

Adolph V. Lombardi; Thomas H. Mallory; Michael M. Alexiades; John M. Cuckler; Philip M. Faris; Kenneth A. Jaffe; E. Michael Keating; Carl L. Nelson; Chitranjan S. Ranawat; Joseph Williams; Richard Wixson; Jodi F. Hartman; Susan G. Capps; Cheryl A. Kefauver

2001-01-01

28

Taper junction failure in large-diameter metal-on-metal bearings  

PubMed Central

Objectives An ongoing prospective study to investigate failing metal-on-metal hip prostheses was commenced at our centre in 2008. We report on the results of the analysis of the first consecutive 126 failed mated total hip prostheses from a single manufacturer. Methods Analysis was carried out using highly accurate coordinate measuring to calculate volumetric and linear rates of the articular bearing surfaces and also the surfaces of the taper junctions. The relationship between taper wear rates and a number of variables, including bearing diameter and orientation of the acetabular component, was investigated. Results The measured rates of wear and distribution of material loss from the taper surfaces appeared to show that the primary factor leading to taper failure is the increased lever arm acting on this junction in contemporary large-diameter metal-on-metal hip replacements. Conclusions Our analysis suggests that varus stems, laterally engaging taper systems and larger head diameters all contribute to taper failure. PMID:23610672

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

2012-01-01

29

The Otto Aufranc Award. Wear and lubrication of metal-on-metal hip implants.  

PubMed

The implication of polyethylene wear particles as the dominant cause of periprosthetic osteolysis has created a resurgence of interest in metal-on-metal implants for total hip arthroplasty because of their potential for improved wear performance. Twenty-two cobalt chromium molybdenum metal-on-metal implants were custom-manufactured and tested in a hip simulator. Accelerated wear occurred within the first million cycles followed by a marked decrease in wear rate to low steady-state values. The volumetric wear at 3 million cycles was very small, ranging from 0.15 to 2.56 mm3 for all implants tested. Larger head-cup clearance and increased surface roughness were associated with increased wear. Independent effects on wear of material processing (wrought, cast) and carbon content were not identified. Implant wear decreased with increasing lambda ratio, a parameter used to relate lubricant film thickness to surface roughness, suggesting some degree of fluid film lubrication during testing. This study provided important insight into the design and engineering parameters that affect the wear behavior of metal-on-metal hip implants and indicated that high quality manufacturing can reproducibly lead to very low wear. PMID:10611857

Chan, F W; Bobyn, J D; Medley, J B; Krygier, J J; Tanzer, M

1999-12-01

30

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

PubMed

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

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

2011-12-23

31

Tribological performance of various CoCr microstructures in metal-on-metal bearings: the development of a more physiological protocol in vitro.  

PubMed

Hip simulators have been used for ten years to determine the tribological performance of large-head metal-on-metal devices using traditional test conditions. However, the hip simulator protocols were originally developed to test metal-on-polyethylene devices. We have used patient activity data to develop a more physiologically relevant test protocol for metal-on-metal devices. This includes stop/start motion, a more appropriate walking frequency, and alternating kinetic and kinematic profiles. There has been considerable discussion about the effect of heat treatments on the wear of metal-on-metal cobalt chromium molybdenum (CoCrMo) devices. Clinical studies have shown a higher rate of wear, levels of metal ions and rates of failure for the heat-treated metal compared to the as-cast metal CoCrMo devices. However, hip simulator studies in vitro under traditional testing conditions have thus far not been able to demonstrate a difference between the wear performance of these implants. Using a physiologically relevant test protocol, we have shown that heat treatment of metal-on-metal CoCrMo devices adversely affects their wear performance and generates significantly higher wear rates and levels of metal ions than in as-cast metal implants. PMID:20436012

Kamali, A; Hussain, A; Li, C; Pamu, J; Daniel, J; Ziaee, H; Daniel, J; McMinn, D J W

2010-05-01

32

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

33

Zweymueller with metal-on-metal articulation: clinical, radiological and histological analysis of short-term results  

Microsoft Academic Search

Background. This is a prospective study. Methods. A total of 266 consecutive patients, who received 350 third-generation Zweymueller-SL total hip arthroplasties with metal-on-metal articulation for primary or secondary osteoarthritis, was followed and evaluated clinically, radiologically and histologically. The age of the patients at the time of surgery was 55Nj years, (range 25-70 years). Seven ( 3%) patients did not return

Panagiotis Korovessis; Georgios Petsinis; Maria Repanti

2003-01-01

34

Short-term results of the M2a-taper metal-on-metal articulation.  

PubMed

A polyethylene-free, metal-on-metal acetabular system (M2a-taper [Biomet, Inc., Warsaw, IN]) was designed in an effort to improve total hip arthroplasty (THA) longevity. Minimum 2-year follow-up results involving 72 polyethylene liner THAs and 78 metal liner THAs from a multicenter, randomized, controlled, investigational device exemption study are reported. Mean Harris hip scores of 95.54 (polyethylene liner group) and 95.23 (metal liner group) were reported at mean follow-up intervals of 3.29 and 3.23 years. Radiographic evaluation revealed no evidence of early failure. No acetabular components have been revised or are pending revision. No statistically significant differences in the data were calculated between liner types except for the immediate postoperative (P=.0415) and minimum 2-year follow-up (P=.0341) angles of inclination. The M2a-taper metal-on-metal articulation may represent a viable alternative for THA in younger, higher demand patients. PMID:11742463

Lombardi, A V; Mallory, T H; Alexiades, M M; Cuckler, J M; Faris, P M; Jaffe, K A; Keating, E M; Nelson, C L; Ranawat, C S; Williams, J; Wixson, R; Hartman, J F; Capps, S G; Kefauver, C A

2001-12-01

35

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 ”g/L were measured (detection limit typically 0.3 ”g/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; Lutzner, Jorg; Seidler, Andreas; Drexler, Hans; Gunther, Klaus-Peter; Schmitt, Jochen

2013-01-01

36

The composition of tribofilms produced on metal-on-metal hip bearings.  

PubMed

Following wear testing in a hip simulator, the bearing surfaces of 36 mm metal on metal total hip replacements showed the formation of tribochemical layers. These layers were investigated in a transmission electron microscope, and analysis was performed using electron energy loss spectroscopy, energy dispersive x-rays and selected area electron diffraction. The tribofilm formed at the edge of the wear scar was 100 s of nanometres thick and contained cobalt sulphide particles embedded within. The film itself was rich in carbon, and appeared to contain no long range graphitic ordering when analysed with electron energy loss spectroscopy, and the spectra gathered from the tribofilm closely resembled those collected from amorphous carbon. The location at which the most substantial tribological layers formed may be explained by the formation of a blunt wedge at the edge of the wear scar following conformal changes to the bearing surfaces. PMID:24333026

Hesketh, James; Ward, Michael; Dowson, Duncan; Neville, Anne

2014-02-01

37

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

38

Elevation of circulating HLA DR+ CD8+ T-cells and correlation with chromium and cobalt concentrations 6 years after metal-on-metal hip arthroplasty  

PubMed Central

Background and purpose Following metal-on-metal hip arthroplasty (THA), immunological reactions including changes in lymphocyte populations, aseptic loosening, and lymphocytic pseudotumors occur. We hypothesized that changes in lymphocyte subpopulations would be associated with elevated metal ion concentrations. Methods A randomized trial involving 85 patients matched for age and sex and randomized to receiving metal-on-metal (n = 41) or metal-on-polyethylene total hip arthroplasty (n = 44) was conducted. 36 patients were eligible for follow-up after mean 7 (6–8) years. Concentrations of chromium and cobalt were analyzed by high-resolution inductively coupled plasma mass spectrometry. Leukocyte subpopulations and immunoglobulins in patient blood were measured using standard laboratory methods. Results Patients with a metal-on-metal hip had higher serum concentrations of chromium (1.05 vs. 0.36 ?g/L; p < 0.001) and cobalt (0.86 vs. 0.24 ?g/L; p < 0.001) than those with metal-on-polyethylene. The percentage of HLA DR+ CD8+ T-cells was higher in the metal-on-metal group (10.6 vs. 6.7%; p = 0.03) and correlated positively with chromium and cobalt concentrations in patient blood (Pearson's correlation coefficient: 0.39, p = 0.02; 0.36, p = 0.03, respectively). The percentage of B-cells was lower in the metal-on-metal group (p = 0.01). The two groups were similar with respect to immunoglobulin concentrations and Harris hip scores, and there were no radiographic signs of loosening. Interpretation We conclude that immunological alterations appear to be associated with increased cobalt and chromium concentrations. It is tempting to speculate that HLA DR+ CD8+ T-cells are involved in the pathogenesis of allergic reactions, implant loosening, and lymphocytic pseudotumors. PMID:21189110

2011-01-01

39

Tribolayer formation in a metal-on-metal (MoM) hip joint: an electrochemical investigation.  

PubMed

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/cm(2)). Further, polarization resistance (Rp:2.39±0.60M?/cm(2)) and capacitance (Cdl:15.20±0.75?F/cm(2)) indicated variation in corrosion kinetics for the tribolayer surface, that attributed to its structure and stability in a simulated body environment. PMID:24099949

Mathew, M T; Nagelli, C; Pourzal, R; Fischer, A; Laurent, M P; Jacobs, J J; Wimmer, M A

2014-01-01

40

Manufacturing methods for machining micro pits of hip implant for metal-on-metal lubrication  

Microsoft Academic Search

Hip implant is an orthopedic procedure which the hip joint is replaced by prosthetic or artificial implant in order to replace arthritic or dysfunctional joint surface. The process is also known as hip arthroplasty. However, the metal-on-metal hips articulation suffers from friction due to the moving metal surface thus, shortening the surviving of the joint. A micro pits formation is

Nor Liyana Safura Hashim; Azli Yahya; Mohammed Rafiq Abdul Kadir; Syahrullail Samion; Nazriah Mahmud

2012-01-01

41

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

42

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

PubMed

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

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

2013-12-01

43

Metal-on-metal bearings: the problem is edge-loading wear.  

PubMed

Metal-on-metal bearings are promoted as a low wear bearing alternative to traditional hip replacement bearings. While most in vitro studies support this, recent clinical reviews have found a significant number of early revisions in some designs of metal-on-metal bearings related to wear. Metal-on-metal bearings exhibit a bi-phasic wear pattern with high initial wear that generally settles down to low steady state wear. Previous publications from the authors have found that steady state wear occurs due to the formation of a critical conforming contact area. This contact area was found to be surprisingly constant regardless of bearing size, clearance, or even contact mode. The authors hypothesized that steady state wear may never be reached if formation of this critical conforming contact area is disrupted. Several hip simulator tests were performed to assess the wear performance of generic metal-on-metal samples at various angles of inclination. Three-dimensional modeling was performed on the generic bearing design as well as typical resurfacing and hemispherical bearing designs including various sizes and clearance ranges. Simulator results support the hypotheses, and wear rates were linear or accelerating when the critical contact area size could not be achieved due to its proximity to the rim of the bearing. Modeling studies show a correlation between bearing size and design and the maximum inclination angle allowed to reach steady state conditions. Smaller bearing size and shallower cup designs were found to reduce the maximum safe inclination angle and this corresponds to clinical observation of increased failure rates in these bearings. This simple method for assessing runaway wear risk can be utilized in the design of more robust and forgiving metal-on-metal bearings. PMID:21082578

Lee, Reginald K; Longaray, Jason; Essner, Aaron; Wang, Aiguo

2010-10-01

44

Breast milk metal ion levels in a young and active patient with a metal-on-metal hip prosthesis.  

PubMed

Metal-on-metal resurfacing arthroplasty of the hip has been used increasingly over the last 10 years in younger active patients. The dissolution of the metal wear particles results in measurable increases in cobalt and chromium ions in the serum and urine of patients with a metal-on-metal bearing. We measured the cobalt, chromium, and molybdenum ion levels in urine; serum; and breast milk in a young and active patient with a metal-on-metal hip prosthesis after a pathologic fracture of the femoral neck. Metal-on-metal hip prosthesis leads to increasing levels of molybdenum in breast milk in the short-term follow-up. There are no increasing levels of chromium and cobalt ions in breast milk. Besides the already known elevated concentrations in serum of chromium and cobalt after implantation of a metal-on-metal hip prosthesis, we found no increasing levels of chromium and cobalt in urine. PMID:22868068

Nelis, Raymond; de Waal Malefijt, Jan; Gosens, Taco

2013-01-01

45

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

46

Transient elastohydrodynamic lubrication analysis of metal-on-metal hip implant under simulated walking conditions.  

PubMed

The transient elastohydrodynamic lubrication (EHL) analysis was performed in this study for a typical metal-on-metal bearing employing a polyethylene backing underneath a metallic cup inlay under dynamic operating conditions of load and speed representative of normal walking. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup. The governing Reynolds and elasticity equations were solved simultaneously by using both finite difference and finite element methods. The predicted transient film thickness from the present study was compared with the estimation based on the quasi-static analysis. It was found that the polyethylene backing employed in the typical metal-on-metal hip bearing, combined with dynamic squeeze-film action, significantly improved the transient lubricant film thickness under cyclic walking and consequently a fluid film lubrication regime was possible for smooth bearing surfaces with an average roughness less than 0.005 microm. PMID:16199048

Liu, F; Jin, Z M; Hirt, F; Rieker, C; Roberts, P; Grigoris, P

2006-01-01

47

Lubrication and friction prediction in metal-on-metal hip implants  

Microsoft Academic Search

A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and

F. C. Wang; C. Brockett; S. Williams; I. Udofia; J. Fisher; Z. M. Jin

2008-01-01

48

Lubrication and friction prediction in metal-on-metal hip implants  

NASA Astrophysics Data System (ADS)

A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup under cyclic operating conditions of representative load and motion. The mixed lubrication model presented in this study was first applied to identify the contact characteristics on the bearing surfaces, consisting of both fluid-film and boundary lubricated regions. The boundary lubricated contact was assumed to occur when the predicted fluid film thickness was less than a typical boundary protein layer absorbed on the bearing surfaces. Subsequently, the friction was predicted from the fluid-film lubricated region with viscous shearing due to both Couette and Poiseuille flows and the boundary protein layer contact region with a constant coefficient of friction. The predicted frictional torque of the typical metal-on-metal hip joint implant was compared with the experimental measurement conducted in a functional hip simulator and a reasonably good agreement was found. The mixed lubrication regime was found to be dominant for the conditions considered. Although the percentage of the boundary lubricated region was quite small, the corresponding contribution to friction was quite large and the resultant friction factor was quite high.

Wang, F. C.; Brockett, C.; Williams, S.; Udofia, I.; Fisher, J.; Jin, Z. M.

2008-03-01

49

Metal-on-metal articulation for artificial hip joints: laboratory study and clinical results.  

PubMed

As wear is inevitable with artificial joint replacement, it has to be minimized to avoid possible aseptic loosening following osteolysis due to particle-initiated foreign body reaction. Co-Cr-Mo-C alloys have a long history with only minimum wear when articulating with themselves. This investigation shows that the choice of the alloy has an effect on the wear rate of this articulation couple. Tribological studies in a screening device, a pendulum apparatus and a hip joint simulator showed a marked influence of the environment as well as the diameter of the implants with metal-on-metal articulation. A wear-resistant combination with low friction characteristics has been developed by using a wrought Co-Cr-Mo-C alloy and reducing the implant diameter to 28 mm. Clinical wear rates are comparable with laboratory data and demonstrate the potential of the metal-on-metal articulation to solve the problem of wear-induced osteolysis of hip joint endoprostheses. PMID:8885660

Streicher, R M; Semlitsch, M; Schön, R; Weber, H; Rieker, C

1996-01-01

50

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

51

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

52

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

53

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

PubMed

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

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

2014-09-01

54

Predicting wear and blood metal ion levels in metal-on-metal hip resurfacing.  

PubMed

Suboptimal component position and design are thought to lead to edge wear and raised blood metal ion levels in metal-on-metal hip resurfacing (MOM-HR). These factors are thought to influence the "contact patch to rim distance" (CPRD), and calculation of this distance may improve prediction of wear and blood metal ion levels. We measured blood cobalt and chromium ion levels and the wear rates of the bearing surfaces in 165 MOM-HR retrieval cases. We then determined the contribution and effect sizes of cup inclination and version angles, component size and design, and CPRD (calculated from case-specific data) on blood metal ion levels and component wear rates. Acetabular orientation explained between 16.3% and 28.5% of the variation in wear rates and metal ion levels, whereas component size and design explained between 7.3% and 21.8% of the variability. In comparison, CPRD explained up to 67.7% of the variability, significantly greater than any other variable (all p < 0.0001). CPRD is a good predictor of wear and improves our understanding of wear performance and the mechanisms leading to edge loading. PMID:24115200

Matthies, Ashley K; Henckel, Johann; Cro, Suzie; Suarez, Alexander; Noble, Philip C; Skinner, John; Hart, Alister J

2014-01-01

55

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

56

Analysis of elastohydrodynamic lubrication in a novel metal-on-metal hip joint replacement.  

PubMed

Elastohydrodynamic lubrication (EHL) analysis was carried out in this study for a novel metal-on-metal hip prosthesis, which consists of a cobalt-chrome alloy femoral head articulating against a cobalt-chrome alloy acetabular insert connected to a titanium fixation shell through a taper. Finite element models were developed to investigate the effect of the pelvic bone and the load on the predicted contact pressure distribution between the two bearing surfaces under dry conditions. The finite element method was used to develop elasticity models for both the femoral and the acetabular components; it was found that the elastic deformation of the acetabular insert was mainly dependent on the load, rather than the detailed pressure distribution. A modified solution methodology was accordingly developed to couple the elasticity models for both the femoral and the acetabular surfaces with the Reynolds equation and to solve these numerically by the finite difference method. It was found that a load increase from 500 to 2500 N had a negligible effect on the predicted maximum contact pressure and the minimum film thickness, due to the relatively flexible and accommodating structure of the acetabular insert. Furthermore, the predicted minimum film thickness was shown to be significantly greater than the simple estimation based on the assumption of semi-infinite solids (mono-block design) using the Hamrock and Dowson formula. The effects of the viscosity of the lubricant and the radial clearance between the femoral and the acetabular components on the predicted lubricating film thickness were investigated under both in vitro simulator testing and in vivo walking conditions. PMID:12137285

Jagatia, M; Jin, Z M

2002-01-01

57

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

PubMed

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

2014-12-01

58

The influence of clearance on friction, lubrication and squeaking in large diameter metal-on-metal hip replacements  

Microsoft Academic Search

Large diameter metal-on-metal bearings (MOM) are becoming increasingly popular, addressing the needs of young and more active\\u000a patients. Clinical data has shown excellent short-to-mid-term results, though incidences of transient squeaking have been\\u000a noted between implantation and up to 2 years post-operative. Geometric design features, such as clearance, have been significant\\u000a in influencing the performance of the bearings. Sets of MOM bearings

Claire L. Brockett; Phil Harper; Sophie Williams; Graham H. Isaac; Rob S. Dwyer-Joyce; Zhongmin Jin; John Fisher

2008-01-01

59

Surface Damage After Multiple Dislocations of a 38-mm-Diameter, Metal-on-Metal Hip Prosthesis  

Microsoft Academic Search

We present, for the first time, a detailed damage assessment of a large-diameter metal-on-metal (L-MOM) hip prosthesis to show the extent of surface damage that can occur in a patient after multiple dislocations. The patient was a man (51 years old) who dislocated 8 times and was finally revised at 27 months. Radiographically, the cup was malpositioned with 65° lateral

John G. Bowsher; Thomas K. Donaldson; Paul A. Williams; Ian C. Clarke

2008-01-01

60

Grading the severity of soft tissue changes associated with metal-on-metal hip replacements: reliability of an MR grading system  

Microsoft Academic Search

Introduction  Metal-on-metal (MoM) soft tissue reactions or aseptic lymphocytic vasculitis-associated lesions (ALVAL) are being recognised\\u000a using metal artefact reduction (MAR) MR with increasing frequency following the advent of second generation metal-on-metal\\u000a bearings, but there is no standardised technique for reporting of MR appearances in this disease. The aim of this study was\\u000a to measure the reliability of a grading system designed

Helen Anderson; Andoni Paul Toms; John G. Cahir; Richard W. Goodwin; James Wimhurst; John F. Nolan

2011-01-01

61

Effect of Corrosion and Biofilm on Friction Behavior in Biotribocorrosion System for Metal-on-Metal Hip Prosthesis  

Microsoft Academic Search

\\u000a The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal\\u000a (PoM) joint prosthesis due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm\\u000a formed under tribological contact are still not fully understood. Bench tests have been carried out to characterize the relationship\\u000a and interactions between electrochemical reactions (corrosion),

Yu Yan; Duncan Dowson; Sophie Williams; Anne Neville; John Fisher

62

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

63

Blood levels of cobalt and chromium are inversely correlated to head size after metal-on-metal resurfacing arthroplasty.  

PubMed

Resurfacing arthroplasty has fallen out of favour in recent years due to unfavourable survivorship in joint registries and alarming reports of soft tissue reactions around metal on metal prostheses. Our aim was to assess the effect of head size, implant design and component positioning on metal production by resurfacing arthroplasties. We measured whole blood cobalt and chromium and component position in matched populations implanted with two designs of resurfacing arthroplasty over a two-year period. Both implants resulted in a significant increase in blood metal levels (p<0.001) though the ASR design generated significantly higher metal levels (p = 0.041). A significant inverse correlation was seen between component size and blood cobalt levels (p = 0.032) and blood chromium levels (p<0.001). No correlation was identified between component position and blood metal levels. Small diameter metal resurfacing components result in increased metal generation compared with larger components. As increased metal generation has been correlated to wear and therefore failure, caution must be used on implantation of smaller components and indeed, in those who require smaller components, alternative bearing materials should be considered. These results contrast with recent findings which have demonstrated early failure for larger diameter stemmed metal-on-metal prostheses. PMID:23813179

Parry, Michael C; Eastaugh-Waring, Steve; Bannister, Gordon C; Learmonth, Ian D; Case, Charles Patrick; Blom, Ashley W

2013-01-01

64

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

65

Significance of Elevated Blood Metal Ion Levels in Patients with Metal-on-Metal Prostheses: An Evaluation of Oxidative Stress Markers  

PubMed Central

It is widely known that cobalt and chromium ions can enhance the production of reactive oxygen species, known to be damaging to cells by disturbing their redox status and then generating oxidative stress. The aim of the present study was to determine if increased metal ion levels induce a state of oxidative stress in patients with metal-on-metal (MM) hip arthroplasty. Results indicated that there was no significant difference in the concentration of oxidative stress markers (total antioxidants, peroxides, and nitrated proteins) in the patients with MM bearings compared to patients without prostheses. The activity antioxidant enzymes was stable (catalase and glutathione peroxidase) or slightly decreased (superoxide dismutase and heme oxygenase-1) over time. This work is the first to determine the biological effects of metal ions released from MM hip implants with regards to mid-term systemic oxidative stress and showed that the increased levels of Co and Cr ions are not associated with significant oxidative stress damage in the plasma of patients with these implants. PMID:21249162

Tkaczyk, Cathy; Petit, Alain; Antoniou, John; Zukor, David J; Tabrizian, Maryam; Huk, Olga L

2010-01-01

66

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

67

Surface damage after multiple dislocations of a 38-mm-diameter, metal-on-metal hip prosthesis.  

PubMed

We present, for the first time, a detailed damage assessment of a large-diameter metal-on-metal (L-MOM) hip prosthesis to show the extent of surface damage that can occur in a patient after multiple dislocations. The patient was a man (51 years old) who dislocated 8 times and was finally revised at 27 months. Radiographically, the cup was malpositioned with 65 degrees lateral opening and 15 degrees retroversion. The retrieved cup was a 1-piece, 38-mm Co-Cr-Mo (M2a; Biomet, Warsaw, Ind) with a titanium-alloy backing. The retrieved components demonstrated all known modes of wear, including a polished wear scar, multidirectional scratching, "stripe" wear, surface contamination of titanium-alloy, front face wear, and backside wear. The clinical significance is that cup positioning remains critical regardless of whether a large diameter head is used or not. PMID:18534503

Bowsher, John G; Donaldson, Thomas K; Williams, Paul A; Clarke, Ian C

2008-10-01

68

USURA IN PROTESI D 'ANCA METAL ON METAL : CONFRONTO TRA DUE SOLUZIONI  

Microsoft Academic Search

Sommario Il problema esaminato riguarda la determinazione e il confronto per via numerica del tasso di usura in due soluzioni per l'artroplastica totale dell'anca che differiscono per le dimensioni della testa articolare. L'usura degli impianti è stata stimata seguendo l'ipotesi di Reye dopo aver calcolato le distribuzioni delle pressioni di contatto mediante modelli FEM tridimensionali; l'analisi numerica è stata affiancata

F. Cosmi; M. Hoglievina

69

Radiographic evaluation of midterm failure rates following metal-on-metal hip resurfacing.  

PubMed

This prospective study examined patient characteristics and radiographic findings for 89 subjects undergoing total hip resurfacing. Thirteen (14.6%) of 89 hips have required revision. Female sex, smaller implant size, and diagnosis of osteonecrosis were associated with lower device survival. No significant differences in acetabular cup angle and stem angle were observed between revised and nonrevised hips. Revision rates for the first 25 hips were 24% and 8% for the last 64 hips. Females accounted for 56% of subjects 1 to 25 and 23% of subjects 26 to 89. Despite representing only 33% of included subjects, females accounted for 62% of revision procedures. The lower device survival proportion in subjects 1 to 25 could not be attributed to acetabular or femoral component malpositioning and can likely be explained by a significantly higher proportion of females enrolled early in the study. PMID:21131164

Rylander, Lucas S; Milbrandt, Joseph C; Wallace, Adam B; Allan, D Gordon

2011-09-01

70

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

PubMed Central

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

2013-01-01

71

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

PubMed

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

2014-12-01

72

Lymphoid aggregates that resemble tertiary lymphoid organs define a specific pathological subset in metal-on-metal hip replacements.  

PubMed

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

Mittal, Saloni; Revell, Matthew; 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

73

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

74

Characterization of protein degradation in serum-based lubricants during simulation wear testing of metal-on-metal hip prostheses.  

PubMed

A size exclusion high performance liquid chromatography (SEC-HPLC) method has been developed which is capable of separation and quantitation of bovine serum albumin (BSA) and bovine serum globulin (BSG) components of serum-based lubricant (SBL) solutions. This allowed characterization of the stability profiles of these proteins when acting as lubricants during hip wear simulation, and identification of wear-specific mechanisms of degradation. Using cobalt-chromium metal-on-metal (MOM) hip joints, it was observed that BSA remained stable for up to 3 days (215K cycles) of wear testing after which the protein degraded in a fairly linear fashion. BSG on the other hand, began to degrade immediately and in a linear fashion with a rate constant of 5% per day. Loss of both proteins occurred via the formation of high molecular weight aggregates which precipitated out of solution. No fragmentation of the polypeptide backbone of either protein was observed. Data obtained suggest that protein degradation was not due to microbial contamination, denaturation at the air-water interface, or frictional heating of articulating joint surfaces in these studies. We conclude that the primary source of protein degradation during MOM simulation testing occurs via high shear rates experienced by SBL solutions at articulating surfaces, possibly coupled with metal-protein interactions occurring as new and reactive metal surfaces are generated during wear testing. The development of this analytical methodology will allow new studies to clarify the role of SBL solutions in wear simulation studies and the interactions and lubricating properties of serum proteins with prosthetic surfaces other than MOM. PMID:20583304

Maskiewicz, Victoria K; Williams, Paul A; Prates, Sarah J; Bowsher, John G; Clarke, Ian C

2010-08-01

75

Transient elastohydrodynamic lubrication analysis of a novel metal-on-metal hip prosthesis with a non-spherical femoral bearing surface.  

PubMed

Effective lubrication performance of metal-on-metal hip implants only requires optimum conformity within the main loaded area, while it is advantageous to increase the clearance in the equatorial region. Such a varying clearance can be achieved by using non-spherical bearing surfaces for either acetabular or femoral components. An elastohydrodynamic lubrication model of a novel metal-on-metal hip prosthesis using a non-spherical femoral bearing surface against a spherical cup was solved under loading and motion conditions specified by ISO standard. A full numerical methodology of considering the geometric variation in the rotating non-spherical head in elastohydrodynamic lubrication solution was presented, which is applicable to all non-spherical head designs. The lubrication performance of a hip prosthesis using a specific non-spherical femoral head, Alpharabola, was analysed and compared with those of spherical bearing surfaces and a non-spherical Alpharabola cup investigated in previous studies. The sensitivity of the lubrication performance to the anteversion angle of the Alpharabola head was also investigated. Results showed that the non-spherical head introduced a large squeeze-film action and also led to a large variation in clearance within the loaded area. With the same equatorial clearance, the lubrication performance of the metal-on-metal hip prosthesis using an Alpharabola head was better than that of the conventional spherical bearings but worse than that of the metal-on-metal hip prosthesis using an Alpharabola cup. The reduction in the lubrication performance caused by the initial anteversion angle of the non-spherical head was small, compared with the improvement resulted from the non-spherical geometry. PMID:21381485

Meng, Q E; Liu, F; Fisher, J; Jin, Z M

2011-01-01

76

(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

77

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

78

Asymmetrical hip loading correlates with metal ion levels in patients with metal-on-metal hip resurfacing during sit-to-stand.  

PubMed

The occurrence of pseudotumours following metal-on-metal hip resurfacing arthroplasty (MoMHRA) has been associated with high serum metal ion levels and consequently higher than normal bearing wear. Measuring ground reaction force is a simple method of collecting information on joint loading during a sit-to-stand (STS). We investigated vertical ground reaction force (VGRF) asymmetry during sit-to-stand for 12 MoMHRA patients with known serum metal ion levels. Asymmetry was assessed using two methods: a ratio of VGRF for implanted/unimplanted side and an absolute symmetry index (ASI). It was found that subjects with high serum metal ion levels preferentially loaded their implanted sides. The difference between the two groups was most apparent during the first 22% of STS. VGRF ratio showed significant and strong correlation with serum metal ion levels (Spearman's rho = 0.8, p = 0.003). These results suggest that individual activity patterns play a role in the wear of MoMHRA and preferential loading of an implanted limb during the initiation of motion may increase the wear of metal-on-metal hip replacements. PMID:24474415

Mellon, Stephen; Grammatopoulos, George; Pandit, Hemant; Murray, David W; Gill, Harinderjit S

2014-01-01

79

The immunobiology of cobalt: demonstration of a potential aetiology for inflammatory pseudotumours after metal-on-metal replacement of the hip.  

PubMed

Abnormal wear of cobalt-containing metal-on-metal joints is associated with inflammatory pseudotumours. Cobalt ions activate human toll-like receptor 4 (TLR4), which normally responds to bacterial lipopolysaccharide (LPS) in sepsis. Activation of TLR4 by LPS increases the expression of chemokines IL-8 and CXCL10, which recruit leukocytes and activated T-cells, respectively. This study was designed to determine whether cobalt induces a similar inflammatory response to LPS by promoting the expression of IL-8 and CXCL10. A human monocytic cell line, derived from acute monocytic leukaemia, was treated with cobalt ions and expression of IL-8 and CXCL10 measured at mRNA and protein levels. Cobalt-treated macrophages showed a 60-fold increase in IL-8 mRNA, and an eightfold increase in production of the mature chemokine (both p < 0.001); expression of the CXCL10 gene and protein was also significantly increased by cobalt (both p < 0.001). Experiments were also performed in the presence of CLI-095, a TLR4-specific antagonist which abrogated the cobalt-mediated increase in IL-8 and CXCL10 expression. These findings suggest that cobalt ions induce inflammation similar to that observed during sepsis by the simultaneous activation of two TLR4-mediated signalling pathways. These pathways result in increased production of IL-8 and CXCL10, and may be implicated in pseudotumour formation following metal-on-metal replacement. PMID:25183586

Lawrence, H; Deehan, D; Holland, J; Kirby, J; Tyson-Capper, A

2014-09-01

80

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; Pajamaki, Jorma; Puolakka, Timo

2014-01-01

81

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  

Microsoft Academic Search

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

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

2010-01-01

82

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.; Beaule, P. E.

2013-01-01

83

A frictional study of total hip joint replacements  

Microsoft Academic Search

Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard bearing surface combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to

S. C. Scholes; A. Unsworth; A. A. J. Goldsmith

2000-01-01

84

Profiling the third-body wear damage produced in CoCr surfaces by bone cement, CoCr, and Ti6Al4V debris: a 10-cycle metal-on-metal simulator test.  

PubMed

Particles of bone cement (polymethyl methacrylate), CoCr and Ti6Al4V were compared for their abrasion potential against CoCr substrates. This appears to be the first study utilizing CoCr and Ti6Al4V particulates to abrade CoCr bearings and the first study profiling the morphology of third-body abrasive wear scratches in a hip simulator. The 5 mg debris allotments (median size range 140-300 ”m) were added to cups mounted both inverted and anatomically with metal-on-metal (MOM) bearings in a 10-cycle, hip simulator test. Surface abrasion was characterized by roughness indices and scratch profiles. Compared to third-body abrasion with metal debris, polymethyl methacrylate debris had minimal effect on the CoCr surfaces. In all, 10 cycles of abrasion with metal debris demonstrated that roughness indices (Ra, PV) increased approximately 20-fold from the unworn condition. The scratch profiles ranged 20-108 ”m wide and 0.5-2.8 ”m deep. The scratch aspect ratio (W/PV) averaged 0.03, and this very low ratio indicated that the 140 ”m CoCr beads had plastically deformed to create wide but shallow scratches. There was no evidence of transfer of CoCr beads to CoCr bearings. The Ti64 particles produced similar scratch morphology with the same aspect ratio as the CoCr particulates. However, the titanium particulates also showed a unique ability to flatten and adhere to the CoCr, forming smears and islands of contaminating metal on the CoCr bearings. The morphology of scratches and metal transfer produced by these large metal particulates in the simulator appeared identical to those reported on retrieved metal-on-metal bearings. PMID:25062741

Halim, Thomas; Burgett, Michelle; Donaldson, Thomas K; Savisaar, Christina; Bowsher, John; Clarke, Ian C

2014-07-01

85

The effects of material combination and lubricant on the friction of total hip prostheses  

Microsoft Academic Search

Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene (UHMWPE) socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard-bearing surface combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to

S. C Scholes; A Unsworth; R. M Hall; R Scott

2000-01-01

86

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

87

A frictional study of total hip joint replacements  

NASA Astrophysics Data System (ADS)

Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard bearing surface combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to investigate the difference in lubrication modes and friction of a range of material combinations using synthetic and biological fluids as the lubricants. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing carboxy methyl cellulose (CMC) fluids as the lubricant. Under these conditions the ceramic-on-ceramic joints showed full fluid film lubrication while the metal-on-metal, metal-on-plastic, diamond-like carbon-coated stainless steel (DLC)-on-plastic and ceramic-on-plastic prostheses operated under a mixed lubrication regime. With bovine serum as the lubricant in the all ceramic joints, however, the full fluid film lubrication was inhibited due to adsorbed proteins. In the metal-on-metal joints this adsorbed protein layer acted to reduce the friction while in the ceramic coupling the friction was increased. The use of bovine serum as the lubricant also significantly increased the friction in both the metal-on-plastic and ceramic-on-plastic joints. The friction produced by the DLC-on-plastic joints depended on the quality of the coating. Those joints with a less consistent coating and therefore a higher surface roughness gave significantly higher friction than the smoother, more consistently coated heads.

Scholes, S. C.; Unsworth, A.; Goldsmith, A. A. J.

2000-12-01

88

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

PubMed Central

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

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

2014-01-01

89

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, T6, L8)-bradykinin) from the skin secretion of the Fujian large-headed frog (Limnonectes fujianensis). The C-terminal 9 residues of this BRP (-LPPGFTPLR) exhibit three amino acid substitutions (L/R at Position 1, T/S at Position 6 and L/F at Position 8) when compared to canonical mammalian bradykinin (BK), but are identical to the kinin sequence present within the cloned kininogen-2 from the Chinese soft-shelled turtle (Pelodiscus sinensis) and differ from that encoded by kininogen-2 of the Tibetan ground tit (Pseudopodoces humilis) at just a single site (F/L at Position 8). These data would imply that the novel BRP is an amphibian defensive agent against predation by sympatric turtles and also that the primary structure of the avian BK, ornithokinin (RPPGFTPLR), is not invariant within this taxon. Synthetic RVAL-(L1, T6, L8)-bradykinin was found to be an antagonist of BK-induced rat tail artery smooth muscle relaxation acting via the B2-receptor. PMID:25268979

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

2014-01-01

90

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

91

Metal-On-Metal Bonding and Rebonding Revisited  

SciTech Connect

Density-functional calculations for a wide variety of metals show that, contrary to the rebonding view of adsorbate bonding, addimers do not have notably longer surface bonds than adatoms, do not reside farther above the surface, and do not meet the rebonding arguments for augmented mobility. Rebonding concepts are found to have some utility in explaining addimer stability.

Bogicevic, A.

1999-02-23

92

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

93

What do we know about taper corrosion in total hip arthroplasty?  

PubMed

Mechanically assisted crevice corrosion (MACC) at metal/metal modular junctions in which at least one of the components is fabricated from cobalt-chromium alloy, has reemerged as a potential clinically significant complication in total hip arthroplasty. The clinical manifestation of MACC may include the development of an adverse local tissue reaction (ALTR), similar to what has been described in association with metal-on-metal bearing total hip and resurfacing arthroplasty. The clinical presentation of MACC-associated ALTRs may include pain and possibly late recurrent dislocations. Abnormal metal artifact reduction sequence magnetic resonance images and elevated serum metal levels (cobalt elevations out of proportion to chromium elevations) can be helpful in the diagnosis of these MACC-associated ALTRs. PMID:24655613

Jacobs, J J; Cooper, H J; Urban, R M; Wixson, R L; Della Valle, C J

2014-04-01

94

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

95

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

96

Fatal cardiomyopathy after revision total hip replacement for fracture of a ceramic liner.  

PubMed

Symptomatic cobalt toxicity from a failed total hip replacement is a rare but devastating complication. It has been reported following revision of fractured ceramic components, as well as in patients with failed metal-on-metal articulations. Potential clinical findings include fatigue, weakness, hypothyroidism, cardiomyopathy, polycythaemia, visual and hearing impairment, cognitive dysfunction, and neuropathy. We report a case of an otherwise healthy 46-year-old patient, who developed progressively worsening symptoms of cobalt toxicity beginning approximately six months following synovectomy and revision of a fractured ceramic-on-ceramic total hip replacement to a metal-on-polyethylene bearing. The whole blood cobalt levels peaked at 6521 ”g/l. The patient died from cobalt-induced cardiomyopathy. Implant retrieval analysis confirmed a loss of 28.3 g mass of the cobalt-chromium femoral head as a result of severe abrasive wear by ceramic particles embedded in the revision polyethylene liner. Autopsy findings were consistent with heavy metal-induced cardiomyopathy.We recommend using new ceramics at revision to minimise the risk of wear-related cobalt toxicity following breakage of ceramic components. PMID:23307670

Zywiel, M G; Brandt, J-M; Overgaard, C B; Cheung, A C; Turgeon, T R; Syed, K A

2013-01-01

97

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

2014-01-01

98

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

99

TETE: Total Education in the Total Environment.  

ERIC Educational Resources Information Center

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

Eblen, William R.

100

Total Artificial Heart  

MedlinePLUS

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

101

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

PubMed Central

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

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

2012-01-01

102

Friction moments of large metal-on-metal hip joint bearings and other modern designs  

Microsoft Academic Search

Modern hip joint replacements are designed to minimise wear problems. The most popular metal-on-polyethylene components are being updated by harder metal and ceramic combinations. However, this has also been shown to influence the friction moments, which could overload the interface between the implant and the body. In this study custom test apparatus was used to measure the joint moments in

N. E. Bishop; F. Waldow; M. M. Morlock

2008-01-01

103

Ref. p. 251] 3.3.1 Metals on metals Landolt-Brnstein  

E-print Network

is devoted. According to the definition of adsorbed layers on surfaces given in Chap. 1 of the present volume, by which they are adsorbed, is topic of Sect. 2. It has long been a debate whether the substantial energy until its adsorption energy is dissipated. Sect. 3 is devoted to this so-called transient (non

Brune, Harald

104

Origin of Compact Triangular Islands in Metal-on-Metal Growth  

SciTech Connect

The microscopic origin of compact triangular islands on close-packed surfaces is identified using kinetic Monte Carlo simulations with energy barriers obtained from density-functional calculations. In contrast to earlier accounts, corner diffusion anisotropy is found to control the shape of compact islands at intermediate temperatures. We rationalize the correlation between the orientation of dendrites grown at low temperatures and triangular islands grown at higher temperatures, and explain why in some systems dendrites grow fat before turning compact.

Bogicevic, Alexander; Lundqvist, Bengt I.; Ovesson, Staffan

1999-07-12

105

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

E-print Network

transferred to an Ominiprobe TEM grid. For the control experiments, bovine calf serum (GIBCO) was dried, serum was dried directly on copper TEM grids (#300 mesh) or silicon membranes. EELS Samples were

Marks, Laurence D.

106

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

PubMed Central

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

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

2014-01-01

107

Enhanced wear and corrosion in modular tapers in total hip replacement is associated with the contact area and surface topography.  

PubMed

Widespread concern exists about adverse tissue reactions after metal-on-metal (MoM) total hip replacement (THR). Concerns have also been expressed with wear and corrosion of taper junctions in THR. We report the effect of surface finish and contact area associated with a single combination of materials of modular tapers. In an in vitro test, we investigated the head/neck (CoCrMo/Ti) interface of modular THRs using commercially available heads. Wear and corrosion of taper surfaces was compared following a 10 million loading cycle. Surface parameters and profiles were measured before and after testing. Electrochemical static and dynamic corrosion tests were performed under loaded and non-loaded conditions. After the load test, the surface roughness parameters on the head taper were significantly increased where the head/neck contact area was reduced. Similarly, the surface roughness parameters on the head taper were significantly increased where rough neck tapers were used. Corrosion testing showed breaching of the passive film on the rough but not the smooth neck tapers. Thus, surface area and surface finish are important factors in wear and corrosion at modular interfaces. PMID:23966288

Panagiotidou, Anna; Meswania, Jay; Hua, Jia; Muirhead-Allwood, Sarah; Hart, Alister; Blunn, Gordon

2013-12-01

108

Compatibility of the totally replaced hip. Reduction of wear by amorphous diamond coating.  

PubMed

Particulate wear debris in totally replaced hips causes adverse local host reactions. The extreme form of such a reaction, aggressive granulomatosis, was found to be a distinct condition and different from simple aseptic loosening. Reactive and adaptive tissues around the totally replaced hip were made of proliferation of local fibroblast like cells and activated macrophages. Methylmethacrylate and high-molecular-weight polyethylene were shown to be essentially immunologically inert implant materials, but in small particulate form functioned as cellular irritants initiating local biological reactions leading to loosening of the implants. Chromium-cobalt-molybdenum is the most popular metallic implant material; it is hard and tough, and the bearings of this metal are partially self-polishing. In total hip implants, prerequisites for longevity of the replaced hip are good biocompatibility of the materials and sufficient tribological properties of the bearings. The third key issue is that the bearing must minimize frictional shear at the prosthetic bone-implant interface to be compatible with long-term survival. Some of the approaches to meet these demands are alumina-on-alumina and metal-on-metal designs, as well as the use of highly crosslinked polyethylene for the acetabular component. In order to avoid the wear-based deleterious properties of the conventional total hip prosthesis materials or coatings, the present work included biological and tribological testing of amorphous diamond. Previous experiments had demonstrated that a high adhesion of tetrahedral amorphous carbon coatings to a substrate can be achieved by using mixing layers or interlayers. Amorphous diamond was found to be biologically inert, and simulator testing indicated excellent wear properties for conventional total hip prostheses, in which either the ball or both bearing surfaces were coated with hydrogen-free tetrahedral amorphous diamond films. Simulator testing with such total hip prostheses showed no measurable wear or detectable delamination after 15,000,000 test cycles corresponding to 15 years of clinical use. The present work clearly shows that wear is one of the basic problems with totally replaced hips. Diamond coating of the bearing surfaces appears to be an attractive solution to improve longevity of the totally replaced hip. PMID:14768485

Santavirta, Seppo

2003-12-01

109

Blueberries Cost/ # Ordered Total  

E-print Network

.00 x _______ $ ________.00 TOTAL BLUEBERRIES AMOUNT: $ ________.00 Strawberries # Ordered Total x STRAWBERRIES AMOUNT: $ ________.00 Strawberries (see below) · Earliglow........................ · Honeoye plants & up = $16.00 per 100 Strawberry Information 75 plants = $18.00 There will be no individual sale

Liskiewicz, Maciej

110

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

111

Total synthesis of pseudodehydrothyrsiferol.  

PubMed

An enantioselective total synthesis of pseudodehydrothyrsiferol has been accomplished. The synthetic sequence highlights formation of the highly strained tetrahydropyran C-ring by a Mitsunobu-type S(N)2 reaction with an oxygen nucleophile. PMID:19113900

Hioki, Hideaki; Motosue, Masatoshi; Mizutani, Yasuhiko; Noda, Akira; Shimoda, Tomoaki; Kubo, Miwa; Harada, Kenichi; Fukuyama, Yoshiyasu; Kodama, Mitsuaki

2009-02-01

112

Anatomic Total Shoulder System  

MedlinePLUS

... TOTAL SHOULDER SYSTEM METHODIST HOSPITAL PHILADELPHIA, PA April 17, 2008 00:00:10 ANNOUNCER: DePuy Orthopedics is ... osteophyte stops and the neck starts, Jerry? 00:17:04 GERALD WILLIAMS, MD: It's harder down at ...

113

Total Variation Electrocardiogram Filtering.  

National Technical Information Service (NTIS)

We examine the performance of Total Variation (TV) smoothing for processing of noisy Electrocardiogram (ECG) recorded by an ambulatory device. The TV smoothing is compared with traditionally-used bandpass filtering using ECG with artificially added noise ...

A. Gribok, M. Buller, R. Hoyt, W. Rumpler

2011-01-01

114

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...

115

Total Synthesis of (?)-Himandrine  

E-print Network

We describe the first total synthesis of (?)-himandrine, a member of the class II galbulimima alkaloids. Noteworthy features of this chemistry include a diastereoselective Diels?Alder reaction in the rapid synthesis of the ...

Movassaghi, Mohammad

116

Robotic total hip arthroplasty.  

PubMed

Modern total hip replacement is typically effective and durable, but early failures do occur. Component position influences functional outcome, durability, and risk of complications. Surgical robotics provides the detail-oriented surgeon with a robust tool to optimize the accuracy and precision of total hip arthroplasty, with the potential to minimize risk of mechanical failure. This article describes efficient workflows for using surgical robotics to optimize surgical precision without increasing surgical complexity. PMID:25199417

Hepinstall, Matthew S

2014-10-01

117

Total Internal Reflection  

NSDL National Science Digital Library

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

America, Optical S.

2008-01-01

118

Total Energy Monitor  

SciTech Connect

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

Friedrich, S

2008-08-11

119

Total colonoscopy in children.  

PubMed Central

One hundred and twenty-three total colonoscopies were performed on 115 children with ages ranging from 3 months to 16 years. The major indications were suspected inflammatory bowel disease and unexplained rectal bleeding. Ninety-seven per cent of all procedures were carried out with sedation only. Adult colonoscopes were used in most of the patients but in babies and small children paediatric instruments were preferable. Total colonoscopy was possible in all patients with a patent colon. The terminal ileum was examined in 63 patients. Endoscopic snare polypectomy was successfully carried out in 8 children and multiple haemangiomas were electrocoagulated in one. Total colonoscopy in this paediatric series proved to be at least as easy, rapid, well-tolerated, and safe as in adults. In selected patients as single colonoscopy can give an accurate diagnosis with biopsy proof and sometimes the opportunity for definitive treatment. PMID:7065694

Williams, C. B.; Laage, N. J.; Campbell, C. A.; Douglas, J. R.; Walker-Smith, J. A.; Booth, I. W.; Harries, J. T.

1982-01-01

120

Total synthesis of (?)-cleistenolide  

Microsoft Academic Search

The total synthesis of (?)-cleistenolide, a novel natural product recently isolated from the annonaceae species cleistochlamys kirkii oliver, is described. The synthesis proceeds starting from easily accessible d-manitol using a selective benzoylation, a selective acetonide deprotection, silylprotection and ring-closing metathesis reaction.

Palakuri Ramesh; H. M. Meshram

2011-01-01

121

Total synthesis of asterredione.  

PubMed

The first total synthesis of asterredione was efficiently accomplished over five linear steps and in 21.5% overall yield. As the crucial step, the 2-quaternary 1,3-cyclopentenedione skeleton of asterredione was readily achieved using the Darzens/ring-expansion strategy developed in our laboratory. The structure of synthesized asterredione was fully confirmed by X-ray crystallography. PMID:24517486

Gai, Sinan; Zhang, Qing; Hu, Xiangdong

2014-03-01

122

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

123

Total Quality Management Seminar.  

ERIC Educational Resources Information Center

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

Massachusetts Career Development Inst., Springfield.

124

Total synthesis of ingenol.  

PubMed

A total synthesis of the biologically important diterpene ingenol has been completed. Ring-closing olefin metathesis was used to construct the strained "inside-outside" tetracyclic skeleton, and a series of diastereoselective reactions were employed to complete the synthesis. Another naturally occurring ingenane, 20-deoxyingenol, has also been prepared. PMID:15600313

Nickel, Andrew; Maruyama, Toru; Tang, Haifeng; Murphy, Prescott D; Greene, Blake; Yusuff, Naeem; Wood, John L

2004-12-22

125

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

126

Laparoscopic total abdominal colectomy  

Microsoft Academic Search

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

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

1992-01-01

127

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...

128

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

129

Total synthesis of ingenol.  

PubMed

Total synthesis of ingenol, a diterpene isolated from the genus Euphorbia, was accomplished on the basis of the novel key reactions. The highly strained ingenane skeleton was constructed through an intramolecular cyclization reaction of an acetylene dicobalt complex followed by a rearrangement reaction of an epoxy alcohol. The C(3),C(4),C(5)-triol moiety was introduced by a stereoselective double dihydroxylation reaction of a diene having C(2)-C(3) and C(4)-C(5) double bonds. PMID:12568608

Tanino, Keiji; Onuki, Kei; Asano, Kohei; Miyashita, Masaaki; Nakamura, Tsuyoshi; Takahashi, Yoshinori; Kuwajima, Isao

2003-02-12

130

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

131

Total quality is people  

SciTech Connect

Confronted by changing market conditions and increased global competition, in 1983 the Commercial Nuclear Fuel Division (CNFD) of Westinghouse Electric embarked on an ambitious plan to make total quality the centerpiece of its long-term business strategy. Five years later, the division's efforts in making continuous quality improvement a way of life among its more than 2,000 employees gained national recognition when it was named a charter recipient of the Malcolm Baldridge National Quality Award. What CNFD achieved during the 1980s was a cultural transformation, characterized by an empowered work force committed to a common vision. The company's quality program development strategy is described.

Vogel, C.E. (Westinghouse Electric Corp., Pittsburgh, PA (United States))

1991-01-01

132

Anisotropic Total Variation Filtering  

SciTech Connect

Total variation regularization and anisotropic filtering have been established as standard methods for image denoising because of their ability to detect and keep prominent edges in the data. Both methods, however, introduce artifacts: In the case of anisotropic filtering, the preservation of edges comes at the cost of the creation of additional structures out of noise; total variation regularization, on the other hand, suffers from the stair-casing effect, which leads to gradual contrast changes in homogeneous objects, especially near curved edges and corners. In order to circumvent these drawbacks, we propose to combine the two regularization techniques. To that end we replace the isotropic TV semi-norm by an anisotropic term that mirrors the directional structure of either the noisy original data or the smoothed image. We provide a detailed existence theory for our regularization method by using the concept of relaxation. The numerical examples concluding the paper show that the proposed introduction of an anisotropy to TV regularization indeed leads to improved denoising: the stair-casing effect is reduced while at the same time the creation of artifacts is suppressed.

Grasmair, Markus, E-mail: Markus.Grasmair@univie.ac.a [University of Vienna, Computational Science Center (Austria); Lenzen, Frank, E-mail: Frank.Lenzen@iwr.uni-heidelberg.d [University of Heidelberg, Heidelberg Collaboratory for Image Processing (Germany)

2010-12-15

133

Total disk arthroplasty.  

PubMed

Spinal fusion remains the gold standard for surgical management of instability and mechanical low back or neck pain. However, even in carefully selected patients, successful clinical results can be difficult to achieve. Reasons for failure include pseudarthrosis and adjacent spine segment disease. The theoretic advantages of removing the painful disk while preserving motion have led to increasing interest in total disk arthroplasty. Although disk replacements have been implanted in Europe for decades, the procedure is relatively new in the United States. Recently, two artificial disks for symptomatic lumbar degenerative disk disease have been approved by the US Food and Drug Administration; several others are undergoing clinical trials. Short-term studies demonstrate similar clinical improvements for both disk replacements and fusion procedures at up to 2-year follow-up. Issues requiring further research include optimal design specifications, potential complications, and appropriate patient selection. Consequently, the long-term benefit of total disk arthroplasty over fusion for the treatment of axial low back or neck pain remains to be determined. PMID:17148618

Lin, Eric L; Wang, Jeffrey C

2006-12-01

134

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

135

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

136

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.

2008-11-24

137

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

138

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

139

Total disc replacement.  

PubMed

Total disc replacement (TDR) (partial disc replacement will not be described) has been used in the lumbar spine since the 1980s, and more recently in the cervical spine. Although the biomechanical concepts are the same and both are inserted through an anterior approach, lumbar TDR is conventionally indicated for chronic low back pain, whereas cervical TDR is used for soft discal hernia resulting in cervicobrachial neuralgia. The insertion technique must be rigorous, with precise centering in the disc space, taking account of vascular anatomy, which is more complex in the lumbar region, particularly proximally to L5-S1. All of the numerous studies, including prospective randomized comparative trials, have demonstrated non-inferiority to fusion, or even short-term superiority regarding speed of improvement. The main implant-related complication is bridging heterotopic ossification with resulting loss of range of motion and increased rates of adjacent segment degeneration, although with an incidence lower than after arthrodesis. A sufficiently long follow-up, which has not yet been reached, will be necessary to establish definitively an advantage for TDR, particularly in the cervical spine. PMID:24412045

Vital, J-M; Boissière, L

2014-02-01

140

Total equipment parts configuration  

SciTech Connect

Florida Power Lights's (FP L's) Turkey Point units were built prior to the establishment of American Society of Mechanical Engineers' Sec. III requirements. Since that time, FP L has voluntarily committed to procuring some spare and replacement parts in compliance with the ordering requirements of ASME Sec. III. New subsystems were designed according to ASME Sec. III requirements. In 1978, 10CFR21 of the Code of Federal Regulations was federally mandated. Environmental qualification concerns and the Three Mile Island incident further complicated the stocking and ordering of spare and replacement parts. Turkey Point assembled a team of quality assurance, quality control, and engineering people and obtained permission to directly access the store department computer so that catalog descriptions could be quickly made available for use by the plant. The total equipment parts configuration (TEPC) system was designed and developed under the direction of the procurement document review team at the Turkey Point nuclear plant. The system is a network of related computer data bases that identifies the equipment at the plant. The equipment (or components that make up a piece of equipment) is identified by a tag/component code system. Each component is further broken down by the manufacturer's parts list or bill of material. A description of the data available to the user, the ways these data can be accessed and displayed, and a description of the data bases and their relation to each other are summarized in this paper.

Ferrare, J.; Panzani, F.

1989-01-01

141

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

E-print Network

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

Roy, Subrata

142

Total Knee Replacement  

PubMed Central

Executive Summary Objective The aim of this review was to assess the effectiveness, in terms of pain reduction and functional improvement, and costing of total knee replacement (TKR) for people with osteoarthritis for whom less invasive treatments (such as physiotherapy, analgesics, anti-inflammatory drugs, intra-articular steroids, hyaluronic acids, and arthroscopic surgery) have failed. Clinical Need Osteoarthritis affects an estimated 10% to 12% of Canadian adults. The therapeutic goals of osteoarthritis treatment are to improve joint mobility and reduce pain. Stepwise treatment options include exercise, weight loss, physiotherapy, analgesics, anti-inflammatory drugs, intra-articular steroids and hyaluronic acids, arthroscopic surgery, and, in severe cases, total joint replacement with follow-up rehabilitation. These treatments are delivered by a range of health care professionals, including physiotherapists, occupational therapists, family physicians, internists, rheumatologists, and orthopedic surgeons. TKR is an end-of-line treatment for patients with severe pain and functional limitations. More women than men undergo knee replacement, and most patients are between 55 and 84 years old. The Technology TKR is a surgical procedure in which an artificial joint or prosthesis replaces a damaged knee joint. The primary indication for TKR is pain, followed by functional limitation. Usually, a person’s daily activities must be substantially affected by pain and functional limitations for him or her to be considered a candidate for TKR. There are 3 different types of knee replacement prostheses. Non-constrained prostheses use the patient’s ligaments and muscles to provide the stability for the prosthesis. Semi-constrained prostheses provide some stability for the knee and do not rely entirely on the patient’s ligaments and muscles to provide the stability. Constrained prostheses are for patients whose ligaments and muscles are not able to provide stability for the knee prosthesis. The most common risks and complications associated with TKR are deep venous thrombosis, infection, stiffness, loosening, and osteolysis. To prevent deep venous thrombosis, patients are treated with heparin prophylactically and/or given support stockings to wear. Patients are also given antibiotics for 24 hours after surgery to minimize the risk of infection. Stiffness is another associated complication. In most patients, it can be avoided by keeping the knee moving in the days and weeks following surgery. The National Institutes of Health in the United States concluded that the indications for TKR should include the following: radiological evidence of joint damage, moderate to severe persistent pain that is not adequately relieved by nonsurgical management, and clinically significant functional limitation resulting in diminished quality of life. Review Strategy In March 2005, the following databases were searched: Cochrane Library International Agency for Health Technology Assessment (first quarter 2005), Cochrane Database of Systematic Reviews (first quarter 2005), Cochrane Central Register of Controlled Trials (first quarter 2005), MEDLINE (1966 to March 2005), MEDLINE In-Process and Other Non-indexed Citations (1966 to March 14, 2005), and EMBASE (1980 to 2005 week 9). The Medical Advisory Secretariat also searched Medscape on the Internet for recent reports on trials that were unpublished but that were presented at international conferences. In addition, the Web site Current Controlled Trials (www.controlled-trials.com) was searched for ongoing trials investigating TKR or unicompartmental knee replacement. No studies were identified that compared TKR to an alternative treatment. Several studies have been reported that compare preoperative measurement scores on targeted measures of functioning and pain to postoperative measurement scores in patients undergoing various TKR procedures. In order for the Medical Advisory Secretariat to measure the effectiveness of TKR and to compare the effectiveness of TKR across studies, effec

2005-01-01

143

Total Laparoscopic Pancreaticoduodenectomy  

PubMed Central

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

Kamyab, Armin

2013-01-01

144

Totally reflexive extensions and modules  

E-print Network

We introduce the notion of totally reflexive extension of rings. It unifies Gorenstein orders and Frobenius extensions. We prove that for a totally reflexive extension, a module over the extension ring is totally reflexive if and only if its underlying module over the base ring is totally reflexive.

Chen, Xiao-Wu

2012-01-01

145

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

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 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

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 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

150

Risk of cancer following primary total hip replacement or primary resurfacing arthroplasty of the hip: a retrospective cohort study in Scotland  

PubMed Central

Background: Release and dispersion of particles arising from corrosion and wear of total hip arthroplasty (THA) components has raised concerns about a possible increased risk of cancer. Concerns have been heightened by a recent revival in the use of metal-on-metal (MoM) hip prostheses. Methods: From a linked database of hospital discharge, cancer registration, and mortality records, we selected a cohort of patients who underwent primary THA (1990–2009) or primary resurfacing arthroplasty (mainly 2000–2009) in Scotland, with follow-up to the end of 2010. Available operation codes did not enable us to distinguish MoM THAs. Indirectly standardised incidence ratios (SIRs) were calculated for selected cancers with standardisation for age, sex, deprivation, and calendar period. Results: The study cohort included 71?990 patients yielding 547?001 person-years at risk (PYAR) and 13?946 cancers diagnosed during follow-up. For the total period of observation combined, the risks of all cancers (SIR: 1.05; 95% CI: confidence interval 1.04–1.07), prostate cancer (SIR: 1.07; 95% CI: 1.01–1.14), and multiple myeloma (SIR: 1.22; 95% CI: 1.06–1.41) were increased. These modest increases in risk emerged in the context of effectively multiple tests of statistical significance, and may reflect inadequate adjustment for confounding factors. For 1317 patients undergoing primary resurfacing arthroplasty between 2000 and 2009 (PYAR=5698), the SIR for all cancers (n=39) was 1.23 (95% CI: 0.87–1.68). Conclusion: In the context of previous research, these results do not suggest a major cause for concern. However, the duration of follow-up of patients receiving recently introduced, new-generation MoM prostheses is too short to rule out a genuinely increased risk of cancer entirely. PMID:23549038

Brewster, D H; Stockton, D L; Reekie, A; Ashcroft, G P; Howie, C R; Porter, D E; Black, R J

2013-01-01

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

School of Architecture, Design and the Built Environment Project Title: Improving metal-on-metal hip resurfacing implants  

E-print Network

structures composed of titanium alloys can be selective laser melted to meet specific mechanical requirements. The new device would take advantage of the capabilities of Selective Laser Sintering (SLS) including

Evans, Paul

153

Femoral neck resorption following hybrid metal-on-metal hip resurfacing arthroplasty: a radiological and biomechanical analysis  

Microsoft Academic Search

Introduction  With the resurgence of resurfacing hip arthroplasty complications such as femoral neck fracture and thinning have been identified.\\u000a We therefore conducted a radiological and biomechanical evaluation of factors affecting femoral neck resorption following\\u000a resurfacing hip arthroplasty (RHA).\\u000a \\u000a \\u000a \\u000a \\u000a Methods  We retrospectively reviewed 61 resurfacing hip arthroplasties in 53 patients with a minimum of a 2-year follow-up. Data regarding\\u000a age, gender, body mass

Jibu Joseph; Michael Mullen; Andrew McAuley; Anand Pillai

2010-01-01

154

Indications for total hip and total knee arthroplasties  

Microsoft Academic Search

A lack of consensus regarding the indications for total hip arthroplasty (THA) and total knee arthroplasty (TKA) has been cited as one reason for the variations in the rates of THA and TKA across the United States. The purposes of this study were to survey orthopaedists in a specific geographic area (New York City) regarding the candidacy of patients with

Carol A. Mancuso; Chitranjan S. Ranawat; John M. Esdaile; Norman A. Johanson; Mary E. Charlson

1996-01-01

155

Total Quality and Organization Development. Total Quality Series.  

ERIC Educational Resources Information Center

As the global business environment becomes more turbulent, quality management seems more indispensable. This book offers strategies for integrating the theory and practice of Total Quality Management (TQM) with organizational-development (OD) theory at all organizational levels. Chapter 1 answers the question "Why Total Quality Management and…

Lindsay, William M.; Petrick, Joseph A.

156

Pylorus-Preserving Total Pancreatectomy  

Microsoft Academic Search

Background\\/Aims: Preservation of the pylorus is an accepted alternative procedure to the classical Whipple operation for pancreatic head resection but data describing its value for total pancreatectomy are sparse. Methods: A prospective analysis of 22 total pancreatectomies performed in a consecutive series of 436 pancreatic resections from 1.11.93 to 1.5.99. Results: 11 patients underwent total pancreatectomy with preservation of the

M. Wagner; K. Z’graggen; C. E. Vagianos; C. A. Redaelli; F. Holzinger; C. Sadowski; C. Kulli; H. Zimmermann; H. U. Baer; M. W. Büchler

2001-01-01

157

UNIVERSITY OF HAWAII AT MANOA FACULTY AND STAFF Men Women Total 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 Men Women Total University of Illinois Chicago 130.6 125.8 129.2 92.2 84.9 89.1 79.8 75.7 77.6 N/A N/A 60.0 75.2 67.6 72.8 66.4 58.5 63.3 42.3 40.6 41.2 Source: AAUP Faculty Salary data (http

Wang, Yuqing

158

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 Manoa Institutional Research miro@hawaii.edu 1 of 8 #12;Men Women Total Men Women Total Men Women Total 21% FTE Employees 2 of 8 #12;Men Women Total Men Women Total Men Women Total Executive Administration

Wang, Yuqing

159

Usual Intake of Total fruit  

Cancer.gov

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

160

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

161

Usual Intake of Total seafood  

Cancer.gov

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

162

Usual Intake of Total dairy  

Cancer.gov

Usual Intake of Total dairy Table A33. Total dairy: 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 2.5 (0.07) 1.0

163

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

164

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

Federal Register 2010, 2011, 2012, 2013

...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 device. The...

2013-04-25

165

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

166

Capacitors - Reactance and Total Capacitance.  

National Technical Information Service (NTIS)

Defines capacitive reactance and gives its symbol. Give the formula and various examples for computing capacitive reactance when frequency and capacitance are known. Shows the method of solving for total capacitance in both series and parallel circuits.

1994-01-01

167

Capacitors - Reactance and Total Capacitance.  

National Technical Information Service (NTIS)

Defines capacitive reactance and gives its symbol. Gives the formula and various examples for computing capacitance reactance when frequency and capacitance are known. Shows the method of solving for total capacitance in both series and parallel circuits.

1994-01-01

168

MUJERES TOTAL BIOLOGIA 16 27  

E-print Network

ESCUELA POLITĂ?CNICA SUPERIOR DERECHO CIENCIAS ECONĂ?MICAS Y EMPRESARIALES #12;MUJERES TOTAL ANATOMIA PATOLOGICA 2 4 ANATOMIA, HISTOLOGIA Y NEUROCIENCIA 8 12 BIOQUIMICA 38 54 CIRUGIA 13 27 FARMACOLOGIA Y

Autonoma de Madrid, Universidad

169

Total arsenic in rice milk.  

PubMed

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

Shannon, Ron; Rodriguez, Jose M

2014-03-01

170

Total synthesis of paracaseolide A.  

PubMed

The total synthesis of paracaseolide A, a valuable cell-cycle progression inhibitor, was accomplished in 8 steps from known compounds, with 6.6% overall yield. The synthetic strategy creates strong potential for diversification. PMID:23324067

Guney, Tezcan; Kraus, George A

2013-02-01

171

Fracture After Total Hip Replacement  

MedlinePLUS

... the American Academy of Orthopaedic Surgeons. Fracture A er Total Hip Replacement A periprosthetic fracture is a ... procedure, the majority of periprosthetic fractures occur a er a patient has spent years functioning well with ...

172

Total transmission and total reflection by zero index materials  

E-print Network

In this report, we achieved total transmission and reflection in a slab of zero index materials with defect(s). By controlling the defect's radius and dielectric constant, we can obtain total transmission and reflection of EM wave. The zero index materials, in this report, stand for materials with permittivity and permeability which are simultaneously equal to zero or so called matched impedance zero index materials. Along with theoretical calculations and simulation demonstrations, we also discuss about some possible applications for the proposed structure such as shielding or cloaking an object without restricting its view. We also suggest a way to control total transmission and reflection actively by using tunable refractive index materials such as liquid crystal and BST. The physics behind those phenomena is attributed to intrinsic properties of zero index materials: constant field inside zero index slab.

Viet Cuong Nguyen; Lang Chen

2010-07-01

173

Total Quality Management Is Total at Fox Valley Technical College.  

ERIC Educational Resources Information Center

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

Tyler, Carol R.

1993-01-01

174

Total Quality in Higher Education. Total Quality Series.  

ERIC Educational Resources Information Center

This volume offers a detailed argument for and description of Total Quality Management (TQM) for institutions of higher education. Chapter 1 elaborates on why TQM is good for higher education and includes some warning as to why implementation at colleges and universities may not be easy. Chapter 2 provides an overview of the history of the TQM…

Lewis, Ralph G.; Smith, Douglas H.

175

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

176

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

177

MUJERES ( * ) TOTAL BIOLOGA 16 22  

E-print Network

TerapĂ©utica 16 12 TOTAL MEDICINA 87 65 PsicologĂ­a BiolĂłgica y de la Salud 2 2 TOTAL PSICOLOGÍA 2 2 2 2 285 243 ANATOMÍA, HIST Y NEUROCIE 8 9 BIOQUÍMICA 29 44 CIRUGÍA 4 16 FARMACOLOGÍA 4 5 MEDICINA 20 30 MEDICINA PREVENTIVA Y SALUD PĂ?BLICA Y MICROBIOLOGÍA 3 6 OBSTETRICIA Y GINECOLOGÍA 2 3 ORGANIZACIĂ?N DE EMPRESAS 1 1

Autonoma de Madrid, Universidad

178

MUJERES ( * ) TOTAL BIOLOGA 10 19  

E-print Network

MEDICINA 46 Psicología Biológica y de la Salud 1 TOTAL PSICOLOGÍA 1 169 Fuente: Oficina de Transferencia de CIRUGÍA 0 3 CIRUGÍA 4 18 FARMACOLOGÍA 4 5 FISIOLOGÍA 2 3 MEDICINA 9 20 MEDICINA PREVENTIVA 6 10 MORFOLOGÍA 3 7 OBSTETRICIA Y GINECOLOGÍA 1 1 PEDIATRÍA 3 3 PEDIATRÍA 5 7 PSIQUIATRÍA 1 2 TOTAL MEDICINA 60 111

Autonoma de Madrid, Universidad

179

Total Library Computerization for Windows.  

ERIC Educational Resources Information Center

Presents a general review of features of version 2.1 of Total Library Computerization (TLC) for Windows from On Point, Inc. Includes information about pricing, hardware and operating systems, modules/functions available, user interface, security, on-line catalog functions, circulation, cataloging, and documentation and online help. A table…

Combs, Joseph, Jr.

1999-01-01

180

Page (Total 3) Philadelphia University  

E-print Network

Page (Total 3) Philadelphia University Faculty of Science Department of Biotechnology and Genetic Engineering Second Semester, 2009/20010 Course Syllabus Course code: 240340Course Title: Food Biotechnology in Foods (Application to food production) Ch. 4 (6) Animal Biotechnology in Foods (Overview) First

181

Enantioselective total synthesis of (-)-laurenditerpenol.  

PubMed

A highly convergent total synthesis of (-)-laurenditerpenol has been accomplished through an organolithium to aldehyde nucleophilic addition. Preparation of the prerequisite key intermediates in optically pure form was based on an improved, short, and efficient synthesis of "wine lactone" from (S)-limonene and Corey's catalytic enantioselective Diels-Alder reaction of 2,5-dimethyl furan with diethyl fumarate. PMID:22905649

Pitsinos, Emmanuel N; Athinaios, Nikolaos; Vidali, Veroniki P

2012-09-01

182

Enantioselective Total Synthesis of (+)-Cassiol  

PubMed Central

An enantioselective total synthesis of (+)-cassiol is reported. The complex derived from Pd2(pmdba)3 and enantiopure t-BuPHOX ligand catalyzes enantioconvergent decarboxylative alkylation to generate the quaternary carbon stereocenter at an early stage. The overall synthetic strategy involves a convergent late-stage coupling of two fragments. The synthesis features a longest linear sequence of eight steps. PMID:19093836

Petrova, Krastina V.; Mohr, Justin T.; Stoltz, Brian M.

2009-01-01

183

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

184

What is Total Quality Management?  

ERIC Educational Resources Information Center

Provides a general overview of Total Quality Management (TQM) and explains why there is pressure for change in higher education institutions. Defines TQM and the various themes, tools, and beliefs that make it different from other management approaches. Presents 14 principles and how they might be applied to student affairs. (RJM)

Bryan, William A.

1996-01-01

185

Pseudopotentials and Total Energy Calculations  

Microsoft Academic Search

It has recently become possible to use pseudopotential and total energy techniques to determine crystal structures, solid-solid phase transformations, lattice constants, bulk moduli, shear moduli, cohesive energies, phonon spectra and other static and dynamical properties of solids. The only inputs are the atomic number and mass of the constituent elements and a group of crystal structures to test, yet the

Marvin L Cohen

1982-01-01

186

Total synthesis of (-)-calyciphylline N.  

PubMed

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

Shvartsbart, Artem; Smith, Amos B

2014-01-22

187

Total synthesis of spirobacillene A.  

PubMed

The first total synthesis of spirobacillene A, an indole alkaloid isolated from Lysinibacillus fusiformis, is reported. A Lewis acid mediated spirocyclization of an anisole derivative onto a tethered ynone was used as a key step, drawing inspiration from a potential biosynthesis of the natural product. PMID:23786419

Unsworth, William P; Cuthbertson, James D; Taylor, Richard J K

2013-07-01

188

Page (Total 4) Philadelphia University  

E-print Network

(2008) for the major "Biotechnology and Genetic Engineering". Course module objectives: The course aimsPage (Total 4) Philadelphia University Faculty of Science Department ofBiotechnology and Genetic Engineering First Semester, 2009/2010 Course Syllabus Course code: 240448Course Title: Protein Biotechnology

189

Total Quality Management for Schools.  

ERIC Educational Resources Information Center

Education in the United Kingdom has been shaped by the advent of local school management and the rapid growth of grant-maintained schools. Total Quality Management (TQM) offers a new way of looking at management principles and structures by identifying the needs of both internal and external customers. This book applies principles of TQM…

Greenwood, Malcolm S.; Gaunt, Helen J.

190

CWRU Training Grants (total: 45)  

E-print Network

CWRU Training Grants (total: 45) Grant Name Funding Source Active Period PI/Program Director Department Predoc Slots Postdoc Slots Short Term Slots Visual Sciences Training Program T32-EY007157-12 Start: 30-SEP-2005 End: 29-SEP-2015 Brady-Kalnay, Susann Biochemistry 5 1 0 Metabolism Training Grant T32-DK

Yang, Sichun

191

Total Synthesis of (+)-Scholarisine A  

PubMed Central

An effective total synthesis and assignment of the absolute configuration of the architecturally challenging (+)-scholarisine A has been achieved via a 20-step sequence. Highlights include a reductive cyclization, involving a nitrile and an epoxide; a modified Fischer indole protocol; a late stage oxidative-lactonization; and an intramolecular cyclization leading to the indolenine ring system of (+)-scholarisine A. PMID:22280070

Adams, Gregory L.; Carroll, Patrick J.; Smith, Amos B.

2012-01-01

192

The first Polish total laryngectomies  

PubMed Central

The total removal of the larynx (total laryngectomy), performed in 1872 by the well-known Viennese surgeon Christian A. Theodor Billroth (1829–1894), was an epoch-making event in the history of surgery and laryngology. This paper presents the first surgeons who performed this operation. The first Pole who performed a total laryngectomy (1877) was Julian Kosi?ski (1833–1914), head of the Surgical Clinic of Imperial University Warsaw. It was the 14th operation of this kind in the world. Several laryngectomies were carried out by Franciszek Ksawery Jawdy?ski (1851–1896), called the father of Polish head and neck surgery, who was the first Pole to excise a malignant neck cancer together with the lymph nodes. The next total laryngectomies were performed by the following Polish surgeons: Jan Mikulicz-Radecki (1850–1905), W?adys?aw H.S. Krajewski (1855–1907), Alfred Obali?ski (1843–1898). According to Jan S?dziak, by 1897 Poland with 16 laryngectomies (per 188 carried out) had occupied the fourth position in the world. The failures of the first laryngectomies were due to such factors as the ignorance of shock pathophysiology, the inability to ensure the patency of the airways during and after the operation, which would result in lung and mediastinum infections, massive haemorrhages and so on. But the primary cause was the lack of constructive collaboration between the laryngologists and the surgeons. PMID:24592132

Paprocka-Borowicz, Malgorzata; Pozowski, Andrzej; Kuciel-Lewandowska, Jadwiga

2013-01-01

193

Total system heat loss measurements  

SciTech Connect

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 was accomplished by quantifying the major heat loss components from a relatively large system: a 6.55-m (21.5-ft)-high steam-water pressurizer operating at 280/sup 0/C (540/sup 0/F) and insulated with all-metallic reflective insulation. Experimentally verified analytical models were used to predict heat losses through the insulation and its joints, and the convective air flow. The other heat loss components were calculated from measured cold surface heat fluxes, hot surface and air temperatures, and changes in water level in the pressurizer. The expected total system heat loss was compared with the total system heat input by measuring the steady-state power input. Significant results from the analysis and experiment included: the insulation heat loss was only 39 percent of the total system loss, the convective air flow was a major heat loss at 33 percent of the total, as previous analyses had indicated, and the heat balance agreed to within 11 percent of the measured power input. Since the additional heat loss components exist to some extent for all insulated systems, regardless of the type of insulation, they must all be considered in the design stage if the desired system heat loss is to be achieved.

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

1981-12-01

194

MUJERES TOTAL BIOLOGIA 16 24  

E-print Network

MEDICINA PREVENTIVA Y SALUD PUBLICA Y MICROBIOLOGIA 2 4 OBSTETRICIA Y GINECOLOGIA 5 7 PEDIATRIA 9 13 MEDICINA 99 73 Psicología Biológica y de la Salud 2 2 TOTAL PSICOLOGÍA 2 2 2 2 332 243 Fecha de referencia NEUROCIENCIA 2 4 BIOQUIMICA 15 28 CIRUGIA 7 15 FARMACOLOGIA Y TERAPEUTICA 1 1 FISIOLOGIA 1 MEDICINA 13 20

Autonoma de Madrid, Universidad

195

Total system heat loss measurements  

SciTech Connect

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 following sources: (1) free convective flows through the insulation system; (2) uninsulated surface; (3) insulation joints; (4) conduction paths that pass through the insulation, such as support feet; and (5) fluid leaks from the insulated system, such as those through valves and pump packing. The object of the present work was to verify analytical methods for predicting total system heat loss. These methods predicted that some of the heat loss components listed above - in particular, free convective air flows - can be significant. Verification was accomplished by quantifying the major heat loss components from a relatively large system: a 6.55-m (21.5-ft)-high steam-water pressurizer operating at 280/sup 0/C (540/sup 0/F) and insulated with all-metallic reflective insulation. Experimentally verified analytical models were used to predict heat losses through the insulation and its joints, and the convective air flow. The other heat loss components were calculated from measured cold surface heat fluxes, hot surface and air temperatures, and changes in water level in the pressurizer. The expected total system heat loss was compared with the total system heat input by measuring the steady-state power input.

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

1983-01-01

196

Infection after total hip arthroplasty.  

PubMed Central

Total hip joint replacement offers dramatic improvement in the quality of life but deep infection is the most feared complication of this procedure. The infection threatens the function of the joint, the preservation of the limb, and occasionally even the life of the patient. For the surgeon it is a disastrous anticlimax, which follows a procedure that may have given the patient freedom from pain and increased mobility. PMID:15239869

Kaltsas, Dimitris S.

2004-01-01

197

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

198

Total System Conceptual Ecological Model  

Microsoft Academic Search

The total South Florida ecosystem encompasses all natural areas that were once interconnected and embedded within the vast\\u000a Everglades basin that originally extended from coast to coast and from the upper Kissimmee basin headwaters to Florida Bay,\\u000a Biscayne Bay, the Gulf of Mexico, and Caloosahatchee and Indian River Lagoon estuaries. Restoration of this system will be\\u000a successful once defining characteristics

John C. Ogden; Steve M. Davis; Tomma K. Barnes; Kimberly J. Jacobs; John H. Gentile

2005-01-01

199

Totally retroperitoneal laparoscopic aortobifemoral bypass.  

PubMed

The classic procedure for aortobifemoral bypass is open surgery. Since the first totally laparoscopic aortobifemoral bypass reported in 1997 by Yves-Marie Dion, laparoscopy has been accepted by several authors as a possible minimally invasive alternative for aorto-iliac occlusive disease. The transperitoneal left retrocolic and retrorenal ways are generally used. The totally retroperitoneal laparoscopic procedure has been described as an alternative to the transperitoneal approach. We report here a totally laparoscopic retroperitoneal approach to performing aortobifemoral bypass. This approach was proposed to a 51-year-old man with aorto-iliac occlusive disease. There was no indication for endovascular revascularization. The patient suffered from 10 metres of bilateral intermittent claudication and lower limb ulcers. During the surgical procedure our patient was placed in a 30-degree right lateral decubitus position. The optical system was first placed in an intra-abdominal position to check the positioning of the trocars in the left retroperitoneal space. The dissection of the retroperitoneal space was performed by CO2 insufflation and by blunt dissection using laparoscopic forceps. The infrarenal aorta was exposed and clamped by laparoscopic clamps. A bifurcated graft was sutured on the left-hand side of the aorta by a running suture. Both prosthetic limbs were tunnelized retroperitoneally to the groin under optical control. The femoral anastomoses were performed by classic open surgery. PMID:18074917

Segers, B; Lemaitre, J; Bosschaerts, Th; Guntz, E; Roman, A; Jozsa, B; Hazane, E; Horn, D; Pastijn, I; Barroy, J P

2007-01-01

200

TOTAL PHENOLIC & TOTAL FLAVONOID CONTENT OF BOUGAINVILLEA GLABRA  

E-print Network

Bougainvillea is a very common ornamental plant grown almost all over the world in tropical and subtropical gardens. In this study, bract and flower parts of two different color paper flowers (Bougainvillea spp.), i.e. yellow and pink were investigated for phenolic content and flavonoid content. Total phenolic and flavonoid content of the bougainvillea glabra choisy and calforina gold flower extracts was determined by using the Folin- Ciocalteu reagent and aluminum chloride (AlCl3) method. The total phenolic content was found to be 65.25 ”g mL-1, 62.56 ”g mL-1 respectively however the flavonoid content was 93.11”g mL-1,73.96”g mL-1 for bougainvillea flower extract. Phenolic acids and flavonoids function as reducing agents and free radical scavengers From the research, it was concluded that the Flowers and bract of bougainvillea being rich in phenolics and flavonoid may provide a good source of antioxidant for treating ailments where oxidative stress is implicated as these flowers as potential sources of bioactive components with high antioxidant properties that may be of interest to consumers and public health workers

Coden Ijptfi; Choisy; Calforina Gold; Flower Extracts; Neha Sahu; Dr. Jyoti Saxena

201

MUJERES ( * ) TOTAL BIOLOGA 18 22  

E-print Network

TOTAL MEDICINA 86 142 PSICOLOGÍA BÁSICA 3 6 PSICOLOGÍA BIOLĂ?GICA Y DE LA SALUD 5 10 PSICOLOGÍA EVOLUTIVA ANATOMÍA, HIST Y NEUROCIE 3 4 BIOQUÍMICA 31 44 CIRUGÍA 8 22 FARMACOLOGÍA 6 9 MEDICINA 18 29 MEDICINA PREVENTIVA Y SALUD PĂ?BLICA Y MICROBIOLOGÍA 4 7 OBSTETRICIA Y GINECOLOGÍA 0 1 PEDIATRÍA 4 6 PSIQUIATRÍA 12 19

Autonoma de Madrid, Universidad

202

Total Synthesis of (+)-Sieboldine A  

PubMed Central

The first total synthesis of (+)-sieboldine A was completed in 20 steps from readily available (3aS,6aR)-3,3a,4,6-atetrahydro-2H-cyclopenta[b]furan-2-one (5). Key steps are: (a) a pinacol-terminated 1,6-enyne cyclization reaction to form the cis-hydrindanone core (11 ? 12), (b) formation of the spiro tetrahydrofuran ring by stereoselective DMDO oxidation of tricyclic dihydropyran intermediate 15, and (c) formation of the unprecedented N-hydroxyazacyclononane ring by cyclization of a thioglycoside precursor (18 ? 19). PMID:20527933

Canham, Stephen M.; France, David J.

2010-01-01

203

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

204

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

205

TVD: Total Variation Diminishing code  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

206

Total Synthesis of (+)-Papulacandin D  

PubMed Central

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

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

2010-01-01

207

Total quality management implementation guidelines  

SciTech Connect

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

Not Available

1993-12-01

208

Total quality management program planning  

SciTech Connect

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

Thornton, P.T.; Spence, K.

1994-05-01

209

Pollution prevention through total quality  

SciTech Connect

Application of Total Quality to AlliedSignal Inc., Kansas City Division's (KCD) Pollution Prevention Program has created a dynamic and focused effort to significantly reduce process inefficiencies and waste generation. KCD is demonstrating TQ's usefulness by empowering associates and obtaining their buy-in and ownership of pollution prevention principles. Specific pollution prevention working groups include: establishing a comprehensive recycling process; (2) capitalizing on Environmentally Conscious Manufacturing (ECM) expertise; and (3) encouraging the internal implementation of ECM. TQ produces the performance results that promote and sustain plant-wide pollution prevention goals and activities. KCD uses AlliedSignall's nine step Process Improvement Problem/Solving Model'' (Appendix A). Although this program only formally began within the past year, many of the tools have been used over the last eight years to achieve pollution prevention objectives. This paper focuses on the new attitude and gives examples of how each of the nine steps is being used in the KCD Pollution Prevention Program. This paper describe s each step of the process and provides specific pollution prevention examples.

Stoltz, D.L.; Byrant, M.G.; Eggers, D.M.; Gough, R.W.; Schlosberg, W.H.

1993-05-01

210

Pollution prevention through total quality  

SciTech Connect

Application of Total Quality to AlliedSignal Inc., Kansas City Division`s (KCD) Pollution Prevention Program has created a dynamic and focused effort to significantly reduce process inefficiencies and waste generation. KCD is demonstrating TQ`s usefulness by empowering associates and obtaining their buy-in and ownership of pollution prevention principles. Specific pollution prevention working groups include: establishing a comprehensive recycling process; (2) capitalizing on Environmentally Conscious Manufacturing (ECM) expertise; and (3) encouraging the internal implementation of ECM. TQ produces the performance results that promote and sustain plant-wide pollution prevention goals and activities. KCD uses AlliedSignall`s nine step ``Process Improvement Problem/Solving Model`` (Appendix A). Although this program only formally began within the past year, many of the tools have been used over the last eight years to achieve pollution prevention objectives. This paper focuses on the new attitude and gives examples of how each of the nine steps is being used in the KCD Pollution Prevention Program. This paper describe s each step of the process and provides specific pollution prevention examples.

Stoltz, D.L.; Byrant, M.G.; Eggers, D.M.; Gough, R.W.; Schlosberg, W.H.

1993-05-01

211

Total synthesis of (-)-4-hydroxyzinowol.  

PubMed

(-)-4-Hydroxyzinowol (1) is a potent inhibitor of P-glycoprotein, which has been implicated in multi-drug resistance in the treatment of cancer. The highly oxygenated structure of 1 comprises a trans-decalin (AB-ring) and a tetrahydrofuran (C-ring) and possesses six acyloxy, one hydroxy, and one alkoxy groups. The challenge of synthesizing 1 is particularly heightened by the nine consecutive stereogenic centers on the 10-carbon decalin skeleton. The total synthesis of this extremely complex structure was achieved in 36 steps from 5-acetoxynaphthalen-1-ol by the judicious application of powerful chemo- and stereoselective reactions. The rhodium-catalyzed asymmetric 1,4-addition of the isopropenyl group set the C7-stereocenter, and the remaining three cis-oriented hydroxy groups (C6, 8, and 9) of the B-ring were stereoselectively constructed in a stepwise fashion. The C5-tetra-substituted and C10-quaternary carbons at the juncture of the AB-ring were then introduced by oxidative dearomatization and Diels-Alder reaction, respectively. After acid-promoted formation of the C-ring ether, the C1-, 2-, 4- and 6-oxygen-based functional groups were stereoselectively installed to deliver the fully functionalized tricycle. Finally, the polyhydroxylated structure was converted to the polyacylated target molecule 1 via regioselective acetylation and benzoylation. PMID:25152070

Todoroki, Hidenori; Iwatsu, Masafumi; Urabe, Daisuke; Inoue, Masayuki

2014-09-19

212

The total domination and total bondage numbers of extended de Bruijn and Kautz digraphsI  

Microsoft Academic Search

In this paper we consider the total domination number and the total bondage number for digraphs. The total bondage number, defined as the minimum number of edges whose removal enlarges the total domination number, measures to some extent the robustness of a network where a minimum total dominating set is required. We determine the total domination number and total bondage

Jia Huang; Jun-Ming Xu

213

The total domination and total bondage numbers of extended de Bruijn and Kautz digraphs  

Microsoft Academic Search

In this paper we consider the total domination number and the total bondage number for digraphs. The total bondage number, defined as the minimum number of edges whose removal enlarges the total domination number, measures to some extent the robustness of a network where a minimum total dominating set is required. We determine the total domination number and total bondage

Jia Huang; Jun-Ming Xu

2007-01-01

214

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

215

Locating and total dominating sets in trees  

Microsoft Academic Search

A set S of vertices in a graph G=(V,E) is a total dominating set of G if every vertex of V is adjacent to a vertex in S. We consider total dominating sets of minimum cardinality which have the additional property that distinct vertices of V are totally dominated by distinct subsets of the total dominating set.

Teresa W. Haynes; Michael A. Henning; Jamie Howard

2006-01-01

216

HAWAII CITIES WITH 1990 & 2000 POPULATION TOTALS  

EPA Science Inventory

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

217

CALIFORNIA CITIES WITH 1990 & 2000 POPULATION TOTALS  

EPA Science Inventory

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

218

NEVADA CITIES WITH 1990 & 2000 POPULATION TOTALS  

EPA Science Inventory

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

219

ARIZONA CITIES WITH 1990 & 2000 POPULATION TOTALS  

EPA Science Inventory

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

220

Total cost model for making sourcing decisions  

E-print Network

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

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

2007-01-01

221

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

222

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

223

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

224

(Nonlocal) Total Variation in Medical Imaging  

E-print Network

. In the case of denoising problems in medical US imaging, results on real patient data (2D) are illustrated(Nonlocal) Total Variation in Medical Imaging Alex Sawatzky - 2011 - #12;#12;(Nonlocal) Total Variation in Medical Imaging Alex Sawatzky - 2011 - #12;#12;(Nonlocal) Total Variation in Medical Imaging

Soatto, Stefano

225

Arthroscopy of symptomatic total knee replacements  

Microsoft Academic Search

Between December 1983 and August 1992, 21 knees in 19 patients with symptomatic total knee replacements were arthroscopically diagnosed. The average time between total knee replacement and arthroscopy was 20 months (ranging from 4 to 84 months). All patients were primary total knee replacements. Metal bars, 5 and 8 mm in diameter and 40 cm in length, were made for

Dae K. Bae; Hong K. Lee; Jong H. Cho

1995-01-01

226

Interactive Refractions with Total Internal Reflection  

E-print Network

Interactive Refractions with Total Internal Reflection Scott T. Davis and Chris Wyman University · Dielectric materials · Refraction · Total internal reflection (TIR) #12;Total internal reflection #12;Background · Planar Refraction [Diefenbach97] · Texture index perturbation [Kay79] [Oliveira00] [Lindholm01

Wyman, Chris

227

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

228

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, Lacine; Kolay, Erdi; Ag?lonu, Yasin; Aslan, Zeyneb; Karg?oglu, Mustafa

2013-01-01

229

Total intrinsic spin for plane gravity waves  

NASA Astrophysics Data System (ADS)

A quantity which measures total intrinsic spin along the z axis is constructed for planar gravity (fields dependent on z and t only), in both the Ashtekar complex connection formalism and in geometrodynamics. The total spin is conserved but (surprisingly) is not a surface term. This constant of the motion coincides with one of four observables previously discovered by Husain and Smolin. Two more of those observables can be interpreted physically as raising and lowering operators for total spin.

Neville, Donald E.

1997-09-01

230

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

231

Total Synthesis of Mycolactones A and B  

PubMed Central

First and second generation total syntheses of mycolactones A and B are reported. The first generation total synthesis unambiguously confirmed our earlier assignment of the relative and absolute stereochemistry of mycolactones A and B. Knowledge of the chemical properties of the mycolactones accumulated through the first generation total synthesis allowed us to implement several major improvements to the original synthesis, including: (1) optimizing the choice of protecting groups, (2) eliminating the unnecessary adjustment of protecting groups, and (3) improving the overall stereoselectivity and synthetic efficiency. The second generation total synthesis consists of 21 longest linear steps, with 8.8% overall yield. PMID:17940589

Song, Fengbin; Fidanze, Steve; Benowitz, Andrew B.; Kishi, Yoshito

2007-01-01

232

Effect of microstructure on the dry sliding friction behavior of CoCrMo alloys used in metal-on-metal hip implants.  

PubMed

The microstructure and its effect on the friction behavior of a medical grade wrought cobalt-chromium-molybdenum (CoCrMo) alloy for surgical implants were studied in this work. In particular, the effects of compression and carbon (C) content on the above characteristics were analyzed. Increasing amounts of deformation resulted in a decrease in the number of annealing twins in the microstructures. In addition, there was an increase in the volume fraction of the hexagonal closed-packed (HCP) phase due to a strain-induced transformation (SIT) from the metastable face-centered cubic (FCC) phase. The high C (HC) alloy had a lower volume fraction of this SIT phase. Friction studies conducted on these alloys revealed a higher coefficient of friction for the HC alloy and no significant effect of SIT on the friction characteristics. PMID:16080175

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

2006-02-01

233

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

234

Total Quality Management in Education. Second Edition.  

ERIC Educational Resources Information Center

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

Sallis, Edward

235

Enumeration of totally positive Grassmann cells  

Microsoft Academic Search

Postnikov (Webs in totally positive Grassmann cells, in preparation) has given a combinatorially explicit cell decomposition of the totally nonnegative part of a Grassmannian, denoted Grk,n+, and showed that this set of cells is isomorphic as a graded poset to many other interesting graded posets. The main result of our work is an explicit generating function which enumerates the cells

Lauren K. Williams

2005-01-01

236

Characterizing complex materials using total scattering  

E-print Network

) ïżœ Paul Lauria (Student) ïżœ Daniel Shoemaker (Student) ïżœ Emily Tencate (Student) ïżœFacilities ïżœ Lujan Center://totalscattering.lanl.gov Total Scattering ? #12;4 ? Idea / drawing by Emily Tencate Emilys corner soon coming to http to the Patterson) is obtained via Fourier transform of the normalized total scattering S(Q): Requirements to obtain

Pennycook, Steve

237

Usual Intake of Total starchy vegetables  

Cancer.gov

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

238

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

239

Total Solar Irradiance Variability: A Review  

NASA Technical Reports Server (NTRS)

Observations of total solar irradiance from space within the last two decaades convinced the skeptics that total irradiance varies over a wide range of periodicities: from minutes to the 11-year solar activity cycle. Analyses based on these space-borne observations have demonstrated that the irradiance variations are directly related to changes at the photosphere and the solar interior.

Pap, Judit M.

1996-01-01

240

Enantioselective total syntheses of cyathane diterpenoids.  

PubMed

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

Nakada, Masahisa

2014-08-01

241

Intensive care monitoring after total joint replacement.  

PubMed

Patient safety is a critical issue in elective total joint replacement surgery. Identifying risk factors that might predict complications and intensive care unit (ICU) admission proves instrumental in reducing morbidity and mortality. The institution's experience with risk stratification and pre-operative ICU triage has resulted in a reduction in unplanned ICU admissions and post-operative complications after total hip replacement. The application of the prediction tools to total knee replacement has proven less robust so far. This work also reviews areas for future research in patient safety and cost containment. PMID:24187358

Kamath, A F; McAuliffe, C L; Gutsche, J T; Kosseim, L M; Hume, E L; Baldwin, K D; Kornfield, Z; Israelite, C L

2013-11-01

242

The total bondage number of grid graphs  

E-print Network

The total domination number of a graph $G$ without isolated vertices is the minimum number of vertices that dominate all vertices in $G$. The total bondage number $b_t(G)$ of $G$ is the minimum number of edges whose removal enlarges the total domination number. This paper considers grid graphs. An $(n,m)$-grid graph $G_{n,m}$ is defined as the cartesian product of two paths $P_n$ and $P_m$. This paper determines the exact values of $b_t(G_{n,2})$ and $b_t(G_{n,3})$, and establishes some upper bounds of $b_t(G_{n,4})$.

Hu, Fu-Tao; Xu, Jun-Ming

2011-01-01

243

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

244

Waardenburg's syndrome associated with total aganglionosis.  

PubMed Central

A Pakistani child of consanguineous parents had signs of Waardenburg's syndrome and total intestinal aganglionosis. This association seems to be a distinct clinical entity with an autosomal recessive mode of inheritance. PMID:6651333

Farndon, P A; Bianchi, A

1983-01-01

245

Safety Precautions for Total Release Foggers  

MedlinePLUS Videos and Cool Tools

... Take Other Common-Sense Precautions For More Information Videos Vacate the treated residence after application Do not ... Do not use more foggers than necessary - Watch Video Exit Accidents involving total release foggers have occasionally ...

246

Development of an Electrohydraulic Total Artificial Heart.  

National Technical Information Service (NTIS)

The third annual report on the development of an implantable untethered Total Artificial Heart (TAH) is presented. The system consists of (1) two blood chambers, and four trileaflet valves fabricated from Angioflex(R), a polyetherurethane, resulting in se...

A. R. Millner, B. Ochs, D. Menn, R. Cumming, R. T. V. Kung

1990-01-01

247

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

248

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

249

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

250

Combinatorics related to the totally nonnegative Grassmannian  

E-print Network

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

Oh, SuHo

2011-01-01

251

ON DEVELOPMENT OF TOTALLY IMPLANTABLE VESTIBULAR PROSTHESIS  

E-print Network

ON DEVELOPMENT OF TOTALLY IMPLANTABLE VESTIBULAR PROSTHESIS Andrei M. Shkel 1 Department vestibular prosthesis. The sensing element of the prosthesis is a custom designed one-axis MEMS gyroscope to stimulate the corresponding vestibular nerve branch. Our preliminary experimental evaluations

Tang, William C

252

Patient Matched Instruments and Total Knee System  

MedlinePLUS

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 ...

253

8, 31433162, 2008 Total ozone over  

E-print Network

, are fossil fuel combustion, biomass burning, lightning and soil microbial 3144 #12;ACPD 8, 3143­3162, 2008 (World Meteorological5 Organization, 2003). Also statistically significant negative trends in total ozone

Paris-Sud XI, Université de

254

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

255

Seed Total Phosphate and Phytic Acid  

Microsoft Academic Search

Both the total amount and composition of seed phosphorus (P) are important to maize end-use quality. Seed total P represents\\u000a a major pool in the flux of P through the agricultural ecology. The phosphate stored in seeds of major crops represents a\\u000a sum equivalent to more than 50% of phosphate fertilizer applied annually worldwide (Lott et al. 2000). Clearly this

Victor Raboy

256

Determination of total menstrual blood loss  

Microsoft Academic Search

Objective: To develop and validate a simple method of measuring total menstrual blood loss using a pictorial representation of blood loss, the menstrual pictogram.Design: A prospective evaluation of total menstrual blood loss measurement by the menstrual pictogram compared to the alkaline hematin technique.Setting: Academic menorrhagia research clinic.Patient(s): One hundred twenty-one women; 62 women complaining of heavy menstrual blood loss, 59

Katrina M Wyatt; Paul W Dimmock; Tracy J Walker; P. M. Shaughn O’Brien

2001-01-01

257

TotalWhite African School Department Nonresident  

E-print Network

Political Science 13 0 01 2 16000 Psychology 21 0 00 3 24000 Religious Studies 9 1 00 0 11001 Romance 0 10 1 3000 Total 1 0 10 1 3NN 000 Adult Health 12 1 01 0 14000 Community Practice 16 0 00 0 16000 Parent-Child Health (Nursing) 10 0 00 0 10000 School of Nursing 1 1 00 0 2000 Total 39 2 01 0 42NU 000

Saidak, Filip

258

Mini-incision for total hip arthroplasty  

Microsoft Academic Search

A group of 42 primary total hip arthroplasties performed through an abridged surgical incision (group 1) was prospectively compared to a cohort of 42 primary total hip arthroplasties performed through a standard surgical incision (group 2). The length of the incision was 8.8 ± 1.5 cm for group 1 and 23.0 ± 2.1 cm for group 2. The groups were

John M Wright; Heber C Crockett; Sam Delgado; Stephen Lyman; Mike Madsen; Thomas P Sculco

2004-01-01

259

Total antioxidant capacity of the Korean diet  

PubMed Central

BACKGROUND/OBJECTIVES The objective of this study was to measure and/or estimate the total antioxidant capacity of the Korean diet. MATERIALS/METHODS Eighty-one plant foods that were expected to exhibit rather high antioxidant activities were selected from the Korean diet using the Fifth Korean National Health and Nutrition Survey (KNHANES V). These foods were categorized into 11 food groups: cereals, potatoes, legumes, nuts, vegetables, kimchies, mushrooms, fruits, fruit juices, sea weeds, and oils. The foods were mixed in the proportions specified in traditional Korean recipes and analyzed. The measured indicators for antioxidant capacities were total phenolics, 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and Trolox equivalent antioxidant capacity (TEAC). RESULTS Total phenolics were high in the fruit juices, nuts, vegetables, and fruits; and the average DPPH, ORAC, and TEAC values were high in the vegetables, fruits, fruit juices, and nuts. The correlation coefficient between the content of total phenolics of each food and the in vitro antioxidant capacity was relatively high at 0.851. The intake of total phenolics per capita per day in the Republic of Korea was estimated to be 127 mg. The total dietary antioxidant capacity (TDAC) values, which were obtained from the total antioxidant capacity of each food, taking into account the intake of each food, were 20,763, 54,335, and 876.4 ”mol of Trolox equivalents using the DPPH, ORAC, and TEAC methods, respectively. The food group that contributed the most to the Korean TDAC was cereals at 39.7%, followed by fruits and vegetables at 27.8% and 13.9%, respectively. The contribution of legumes, nuts, fruit juices, and mushrooms was quite minimal at less than 2% each. CONCLUSIONS The content of total phenolics and the antioxidant capacity of the Korean diet are significantly correlated and the high contributing food groups are cereals, fruits, and vegetables. PMID:24741403

Han, Jeong-Hwa; Lee, Hye-Jin; Cho, Mi Ran; Chang, Namsoo; Kim, Yuri; Oh, Se-Young

2014-01-01

260

Total variation diminishing Runge-Kutta schemes  

Microsoft Academic Search

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

Sigal Gottlieb; Chi-wang Shu

1998-01-01

261

Total lymphoid irradiation and discordant cardiac xenografts  

SciTech Connect

Total lymphoid irradiation can prolong concordant cardiac xenografts. The effects of total lymphoid irradiation in a discordant xenograft model (guinea pig to rat) were studied with and without adjuvant pharmacologic immunosuppression. Inbred Lewis rats were randomly allocated to one of four groups. Group 1 (n = 6) served as a control group and rats received no immunosuppression. Group 2 (n = 5) received triple-drug therapy that consisted of intraperitoneal azathioprine (2 mg/kg), cyclosporine (20 mg/kg), and methylprednisolone (1 mg/kg) for 1 week before transplantation. Group 3 animals (n = 5) received 15 Gy of total lymphoid irradiation in 12 divided doses over a 3-week period. Group 4 (n = 6) received both triple-drug therapy and total lymphoid irradiation as described for groups 2 and 3. Complement-dependent cytotoxicity assay was performed to determine if a correlation between complement-dependent cytotoxicity and rejection-free interval existed. Rejection was defined as cessation of graft pulsation and was confirmed by histologic test results. Only groups 1 and 2 showed a difference in survival (group 1, 6.9 +/- 1.0 minutes; group 2, 14.2 +/- 2.7 minutes, p = 0.02). Although total lymphoid irradiation did decrease complement-dependent cytotoxicity, linear regression revealed no correlation between complement-dependent cytotoxicity and graft survival (coefficient of correlation, 0.30). Unlike concordant cardiac xenografts, total lymphoid irradiation with or without triple-drug therapy does not prolong graft survival.

Kaplan, E.; Dresdale, A.R.; Diehl, J.T.; Katzen, N.A.; Aronovitz, M.J.; Konstam, M.A.; Payne, D.D.; Cleveland, R.J. (Tufts Univ. School of Medicine, Boston, MA (USA))

1990-01-01

262

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

263

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

264

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

265

The US 2017 Total Solar Eclipse Workshops  

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

266

Assay development status report for total cyanide  

SciTech Connect

A validated cyanide assay that is applicable to a variety of tank waste matrices is necessary to resolve certain waste tank safety issues and for purposes of overall waste characterization. The target for this effort is an assay with an applicable range of greater than 1,000 ppM (0.10 wt%) total cyanide and a confidence level greater than 80%. Figure 1 illustrates the operating regime of the proposed cyanide assay method. The Assay Development Status Report for Total Cyanide will summarize the past experience with cyanide analyses on-tank waste matrices and will rate the status of the analytical methods used to assay total cyanide (CN{sup {minus}} ion) in the tank waste matrices as acceptable or unacceptable. This paper will also briefly describe the current efforts for improving analytical resolution of the assays and the attempts at speciation.

Simpson, B.C. [Westinghouse Hanford Co., Richland, WA (United States); Jones, T.E.; Pool, K.H. [Pacific Northwest Lab., Richland, WA (United States)

1993-02-01

267

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

268

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

269

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

270

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

271

Laparoscopic total extraperitoneal repair of lumbar hernia  

PubMed Central

Lumbar hernia is a rare surgical entity without a standard method of repair. With advancements in laparoscopic techniques, successful lumbar herniorrhaphy can be achieved by the creation of a completely extraperitoneal working space and secure fixation of a wide posterior mesh. We present a total extraperitoneal laparoendoscopic repair of lumbar hernia, which allowed for minimal invasiveness while providing excellent anatomical identification, easy mobilization of contents and wide secure mesh fixation. A total extraperitoneal method of lumbar hernia repair by laparoscopic approach is feasible and may be an ideal option. PMID:22111086

Lim, Man Sup; Lee, Hae Wan; Yu, Chang Hee

2011-01-01

272

Measuring Total and Germinable Spore Populations  

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

273

The first total synthesis of (±)-1-desoxyhypnophilin  

Microsoft Academic Search

The paper describes the first total synthesis of (±)-1-desoxyhypnophilin, a linear triquinane from the East African mushroom Lentinus crinitus which displays promising antimicrobial activity. A key feature is the use of a ring closing metathesis reaction with a tertiary allylic alcohol, in conjunction with a PCC induced oxidative rearrangement, to construct a cyclopentenone.

David C Harrowven; Matthew C Lucas; Peter D Howes

2001-01-01

274

URINARY TOTAL ANTIOXIDANT CAPACITY IN SOCCER PLAYERS  

Microsoft Academic Search

Both aerobic and anaerobic exercise contributes to oxidative stress by generation of free radicals. The human body is well equipped with both enzymatic and non-enzymatic antioxidant defence system. Soccer predominantly involves aerobic exercise with repeated bouts of anaerobic activities. The response of the different antioxidants to exercise might be sports-specific and hence the total antioxidant capacity (TAC) provides a better

Swarup Mukherjee; Michael Chia

275

Total main rotor isolation system analysis  

NASA Technical Reports Server (NTRS)

The requirements for a preliminary design study and verification procedure for a total main rotor isolation system at n/rev are established. The system is developed and analyzed, and predesign drawings are created for an isolation system that achieves over 95 percent isolation of all six degrees of freedom.

Halwes, D. R.

1981-01-01

276

COHYST 2010 A Total Water Budget  

E-print Network

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

Nebraska-Lincoln, University of

277

Total Quality Management: The Emperor's Tailor.  

ERIC Educational Resources Information Center

Conversations among educators, business leaders, legislators, and educational reformers have generated support for the application of Total Quality Management (TQM) to education. This paper considers whether TQM is indeed the solution to education's problems. After a brief explanation of TQM theory, the paper is organized around four broad issues…

Alexander, Gary C.; Keeler, Carolyn M.

278

Bearing couples in total hip arthroplasty.  

PubMed

Total hip arthroplasty is a well-established treatment for arthritis of the hip. The choice of bearing couple used for articulation should be tailored to the patient. This article reviews the history of different bearing surfaces, and outlines the advantages and disadvantages that may influence their use. PMID:20852486

Tailor, Hiteshkumar; Patel, Shelain; Patel, Rahul V; Haddad, Fares S

2010-08-01

279

Early dislocation after total hip arthroplasty  

Microsoft Academic Search

Background: The average incidence of dislocation after total hip arthroplasty is approximately 3%. However, the choice of surgical approa- ch can affect the rate of postoperative dislocation. A 5.8% dislocation rate has previously been reported when a poste- rolateral approach was used compaired with z.3% when an anterolateral approa- ch was used. The aim of this study was therefore to

N. Levi; P. Gebuhr

2001-01-01

280

Multicultural Leadership, Sustainable Total School Environment  

ERIC Educational Resources Information Center

Banks (2002) stated that to implement multicultural education successfully, we must think of the school as a social system. Therefore, if educational equity and excellence are to be provided to all students, a systemic Total School Environment [Banks (2001) "Cultural diversity and education: Foundations curriculum and teaching, 4th ed." Allyn and…

Yeung, See-Wai Alison; Lee, Yeung; Yue, K. W. Ryan

2006-01-01

281

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

282

Total synthesis of monosporascone and dihydromonosporascone.  

PubMed

The first total synthesis of monosporascone is presented. The five-step synthesis developed includes a silver acetylide-acid chloride coupling, domino Diels-Alder-retro-Diels-Alder reaction, and an intramolecular Friedel-Crafts acylation, and provides the natural product in 57% yield overall. Selective reduction of monosporascone also afforded the related metabolite dihydromonosporascone. PMID:24668447

Punch, Kathryn A; Piggott, Matthew J

2014-05-01

283

EVENT PRICE QUANTITY TOTAL Golf Tournament $60  

E-print Network

$7 Shuttle Bus $7 UGA vs. Old Miss on the Big Screen! Complimentary TOTAL ENCLOSED Make Checks. Tours are led by student ambassadors who will explain a day in the life of a Warnell student. Annual of driving & parking! UGA vs. Ole Miss on the Big Screen! 3:30 pm (estimated kick-off) Stick around after

Teskey, Robert O.

284

Invariant Ordering of Item-Total Regressions  

ERIC Educational Resources Information Center

A new observable consequence of the property of invariant item ordering is presented, which holds under Mokken's double monotonicity model for dichotomous data. The observable consequence is an invariant ordering of the item-total regressions. Kendall's measure of concordance "W" and a weighted version of this measure are proposed as measures for…

Tijmstra, Jesper; Hessen, David J.; van der Heijden, Peter G. M.; Sijtsma, Klaas

2011-01-01

285

Enantiospecific total synthesis of macrolactone Sch 725674.  

PubMed

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

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

2014-08-01

286

Needed: A Theory of Total Factor Productivity  

Microsoft Academic Search

This paper evaluates the argument that differences in physical and intangible capital can account for the large international income differences that characterize the world economy today. The finding is that they cannot. Savings rate differences are of minor importance. What is all-important is total factor productivity (TFP). In addition, the paper presents industry evidence that TFPs differ across countries and

Edward C. Prescott

1998-01-01

287

Total Factor Productivity and the Mongolian Transition  

Microsoft Academic Search

Total Factor Productivity (TFP)is often used on the macro-economic level as an indicator of changes in efficiency of a country. In many transition economies TFP is seen to have been negative the last decade of the plan economy and starts increasing and become positive after a (quite a) few years of transition. Many authors conclude that this is a gain

Antonio G. Chessa; Marije C. Schouwstra

2005-01-01

288

Total Factor Productivity in Korean Manufacturing Industries  

Microsoft Academic Search

In this study, parametric and non-parametric methods are employed to measure the total factor productivity (TFP) growth in the Korean manufacturing industry from 1993 to 2003. The analysis period contains both periods before and after the Asian financial crisis. The TFP growth rate is decomposed into different components. Also different elasticities are reported. By classifying the results by period and

Inha Oh; Jeong-Dong Lee; Almas Heshmati

2008-01-01

289

Implications of Total Quality Management in Education.  

ERIC Educational Resources Information Center

Total Quality Management in Education is a systems model that involves internal and external stakeholders in developing practices, establishing partnership teams, enhancing individual growth, and increasing communication. Walk the Talk in Texas is an example of successful application of the model. (SK)

Wiedmer, Terry L.; Harris, Vicki L.

1997-01-01

290

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

291

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.

292

Total reliability management for telecommunications software  

Microsoft Academic Search

Total reliability management for telecommunications software is essential in achieving high quality network products and a high level of network integrity. The special characteristics and reliability goals of telecommunications software are reviewed, followed by a description of the components of an effective strategy for comprehensive software reliability management. The programs of fault prevention, fault detection, fault removal, failure detection, failure

Ming-Yee Lai; K. F. Rauscher

1993-01-01

293

REGULARIZATION BY TRUNCATED TOTAL LEAST SQUARES  

Microsoft Academic Search

The total least squares (TLS) method is a successful method for noise reduction in linear least squares problems in a number of applications. The TLS method is suited to problems in which both the coefficient matrix and the right-hand side are not precisely known. This paper focuses on the use of TLS for solving problems with very ill-conditioned coefficient matrices

R. D. FIERRO; G. H. GOLUB; P. C. HANSEN; D. P. O'LEARY

1993-01-01

294

Animals, Zombanimals, and the Total Turing Test  

Microsoft Academic Search

Alan Turing devised his famous test (TT) through a slight modificationof the parlor game in which a judge tries to ascertain the gender of twopeople who are only linguistically accessible. Stevan Harnad hasintroduced the Total TT, in which the judge can look at thecontestants in an attempt to determine which is a robot and which aperson. But what if we

Selmer Bringsjord; Clarke Caporale; Ron Noel

2000-01-01

295

Implementing Total Quality Management in Construction Firms  

Microsoft Academic Search

As building projects get larger and more complex, clients are also increasingly demanding higher standards for their delivery. Total quality management ~TQM! has been recognized as a successful management philosophy in the manufacturing and service indus- tries. TQM can likewise be embraced in the construction industry to help raise quality and productivity. Two case studies of construction companies showed how

Low Sui Pheng; Jasmine Ann Teo

2004-01-01

296

The benefits of total quality management  

Microsoft Academic Search

In this article, we will review the implementation of the ISO 9000 quality system in the Department of Nuclear Medicine. We will also discuss the benefits of working with the ISO 9000 standards and explain why we have shifted our focus from ISO 9000 towards the EFQM model. After an introduction concerning Total Quality Management and the EFQM model, we

H. P. A. Geraedts; R. Montenarie; P. P van Rijk

2001-01-01

297

Starting Total Quality Management from ISO 9000  

Microsoft Academic Search

Some 20,000 companies have been registered as working to the International Quality Management Standard ISO 9000, but many have not achieved the improvements in their operations that can be obtained from managing on total quality management principles. ISO 9000 can be an excellent start to TQM, if it is interpreted in a way that encourages the company to start on

Michael Bradley

1994-01-01

298

Total body infrared imaging and postural disorders  

Microsoft Academic Search

Agonist-antagonist and contralateral musculatures of lower extremities, abdomen, pelvis, trunk, and back, co-work to maintain unaware antalgic orthostatic positions caused by postural disorders. Such positions involve a different activity of the several muscular groups. This results in their different working loads and metabolic rates, which may produce specific skin temperature patterns. In this study, comparison of total body infrared imaging

A. Merla; V. Romano; F. Zulli; R. Saggini; L. Di Donato; G. L. Romani

2002-01-01

299

Total Quality Management: Institutional Research Applications.  

ERIC Educational Resources Information Center

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

Heverly, Mary Ann

300

Daily variations in TOMS total ozone data  

SciTech Connect

The spatial and seasonal distributions of daily fluctuations in total ozone from 60{degree}N to 60{degree}S are analyzed by using 14.5 years of total ozone mapping spectrometer (TOMS) data on a 5{degree} latitude by 15{degree} longitude grid. Root mean square day to day differences maximize near 30 Dobson units (DU) in the midlatitudes of both hemispheres from late fall to early spring. The contributions of these fluctuations due to planetary- and medium-scale waves are analyzed using sinusoidal zonal wave filtering. Daily midlatitude variations from planetary-scale waves are smaller than those from medium-scale waves and mainly occur from late fall to early spring, while strong medium-scale variations persist throughout fall, winter, and spring. An exception is the southern hemisphere high latitudes, where contortions and breakup of the polar vortex cause large daily variations on planetary scales during September and October. Tropical total ozone fluctuations due to planetary-scale waves are slightly larger than those due to medium-scale waves in all seasons. A climatological table of monthly RMS day to day total ozone changes is provided as a reference.{copyright} 1997 American Geophysical Union

Allen, D.R.; Reck, R.A. [Global Climate Change Program, Argonne National Laboratory, Argonne, Illinois (United States)] [Global Climate Change Program, Argonne National Laboratory, Argonne, Illinois (United States)

1997-06-01

301

Total knee arthroplasty with the PFC system  

Microsoft Academic Search

consecutive series of 235 total knee arthroplasties using the PFC system was followed prospectively for at least ten years in 186 patients. The operation was for osteoarthritis in 150 knees, for rheumatoid arthritis in 83, and for Paget's disease and femoral osteonecrosis in one knee each. At the latest review 56 patients had died, fi ve were too ill to

Pascal A. Schai; Thomas S. Thornhill; Richard D. Scott

1998-01-01

302

Transforming Schools through Total Quality Education.  

ERIC Educational Resources Information Center

Deming's work emphasizes advantages of teamwork, investment in ongoing training for all employees to increase their value to the company, and insistence that research and employee-gathered data guide and inform every decision and improvement effort. The parallel between psychologist Mihaly Csikszenmihalyi's work and Deming's shows that Total…

Schmoker, Mike; Wilson, Richard B.

1993-01-01

303

Total synthesis of (±)-maistemonine and (±)-stemonamide.  

PubMed

The first total synthesis of polycyclic Stemona alkaloid maistemonine has been achieved. The efficient approach features a stereoselective intramolecular Schmidt reaction, a ketone-ester condensation, and a Reformatsky reaction. Additionally, another Stemona alkaloid stemonamide was divergently synthesized from a common intermediate. PMID:21120242

Chen, Zhi-Hua; Zhang, Yong-Qiang; Chen, Zhi-Min; Tu, Yong-Qiang; Zhang, Fu-Min

2011-02-14

304

First total synthesis of paracaseolide A.  

PubMed

The first total synthesis of the paracaseolide A, a very unusual tetraquinane oxa-cage bislactone recently isolated from the mangrove Sonneratia paracaseolaris, has been achieved. The final step and culmination of the eight-step synthetic sequence is a [4 + 2] dimerization of a 4-hydroxybutenolide, generated by singlet oxygen-mediated oxidation of a furan precursor. PMID:22734450

Noutsias, Dimitris; Vassilikogiannakis, Georgios

2012-07-20

305

Total synthesis of 6'-hydroxyjusticidin A.  

PubMed

The first total synthesis of 6'-hydroxyjusticidin A, isolated from Justicia procumbens L. with good inhibitory activity against cancer cells, has been accomplished. The structure was confirmed by čH NMR, čłC NMR, and HR-ESI-MS. The key steps involved a Diels-Alder cycloaddition reaction and a reduction in NaBH?. PMID:22375869

Xiong, Lu; Bi, Ming-Gang; Wu, Song; Tong, Yuan-Feng

2012-01-01

306

Total Solar Irradiance Satellite Composites and their  

E-print Network

Chapter 12 Total Solar Irradiance Satellite Composites and their Phenomenological Effect on Climate Nicola Scafetta Active Cavity Radiometer Irradiance Monitor (ACRIM) Lab, Coronado, CA 92118, USA, Duke. Phenomenological solar signature on climate 310 9. Conclusion 312 1. INTRODUCTION A contiguoustotal solar

Scafetta, Nicola

307

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

Microsoft Academic Search

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

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

1993-01-01

308

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

309

Physical and psychosocial consequences of total laryngectomy.  

PubMed

The incidence and severity of respiratory symptoms after total laryngectomy and their influence on daily living were studied in 59 laryngectomized patients. Daily sputum production was the principal complaint of these patients (98%), followed by coughing (64%) and the need for frequent forced expectoration (more than 5 times a day) in order to clear the airway (57%). Frequent stoma cleaning (more than 5 times a day) was required by 37% of the patients. Significant correlation was found between respiratory symptoms, voice rehabilitation and several aspects of daily living, including fatigue, sleep problems, social contacts and psychological distress. These findings indicate that respiratory symptoms after total laryngectomy are both frequent and troublesome. The development of effective methods for minimizing and/or preventing such respiratory problems would contribute significantly to improving the quality of life of laryngectomized patients. PMID:2282704

Hilgers, F J; Ackerstaff, A H; Aaronson, N K; Schouwenburg, P F; Van Zandwijk, N

1990-10-01

310

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

311

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

Budzynski, Andrzej; Zub-Pokrowiecka, Anna; Zychowicz, Anna; Wierdak, Mateusz; Matlok, Maciej; Zajac, Malgorzata

2014-01-01

312

The totally constrained model: three quantization approaches  

NASA Astrophysics Data System (ADS)

We provide a detailed comparison of the different approaches available for the quantization of a totally constrained system with a constraint algebra generating the non-compact group. In particular, we consider three schemes: the Refined Algebraic Quantization, the Master Constraint Programme and the Uniform Discretizations approach. For the latter, we provide a quantum description where we identify semiclassical sectors of the kinematical Hilbert space. We study the quantum dynamics of the system in order to show that it is compatible with the classical continuum evolution. Among these quantization approaches, the Uniform Discretizations provides the simpler description in agreement with the classical theory of this particular model, and it is expected to give new insights about the quantum dynamics of more realistic totally constrained models such as canonical general relativity.

Gambini, Rodolfo; Olmedo, Javier

2014-08-01

313

Total knee arthroplasty in patients with poliomyelitis.  

PubMed

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

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

2007-06-01

314

Total knee replacement for patellofemoral disease.  

PubMed

This study evaluates the technical results and outcomes of total knee replacement (TKR) in a group of patients with isolated patellofemoral disease based on the amount of bone loss and patella subluxation seen at the time of surgery. Thirty-three TKRs in 25 patients comprised the study group. All patients had radiographic evidence of isolated end-stage disease in the patellofemoral joint and had cemented tri-compartmental knee replacements. All patellae could be resurfaced. Average follow-up was 5.2 years (range: 3.8-8.4 years). Average Knee Society Scores was 62 preoperatively and 96 at final follow-up. There was no correlation in outcomes related to either the amount of patellar wear, size of the patella, or amount of subluxation of the patella. Total knee replacement is an effective means of managing end-stage arthritis of the patellofemoral joint. PMID:16262008

Dalury, David F

2005-10-01

315

Total body irradiation in chronic myeloid leukemia  

SciTech Connect

Total body irradiation (TBI), given as 10 rad daily for five days a week for a total dose of 150 rad has been used in an attempt to control the chronic phase of chronic myeloid leukemia (CML). Thirteen patients with CML received fractionated TBI leading to rapid and good control of WBC count without any adverse reaction. The chronic phase of CML could also be controlled with TBI, even in three patients who were resistant to busulfan. Following TBI, WBC count remained under control for a period of 32 weeks as compared to 40 weeks following vusulfan alone. Repeat TBI was also well tolerated with good response. It appears that TBI is an effective and safe therapy for controlling the chronic phase of CML.

Advani, S.H.; Dinshaw, K.A.; Nair, C.N.; Ramakrishnan, G.

1983-04-01

316

Fractionated total body irradiation for metastatic neuroblastoma  

SciTech Connect

Twelve patients over one year old with neuroblastoma (NBL) metastatic to bone and bone marrow entered a study of adjuvant low-dose, fractionated total body irradiation (TBI). Six children who achieved a ''complete clinical response'' following chemotherapy (cyclophosphamide and adriamycin) and surgical resection of the abdominal primary received TBI (10 rad/fraction to totals of 100-120 rad/10-12 fx/12-25 days). Two children received concurrent local irradiation for residual abdominal tumor. The intervals from cessation of chemotherapy to documented progression ranged from 2-16 months, not substatially different from patients receiving similar chemotherapy and surgery without TBI. Three additional children with progressive NBL received similar TBI (80-120 rad/8-12 fx) without objective response.

Kun, L.E. (Medical Coll. of Wisconsin, Madison); Casper, J.T.; Kline, R.W.; Piaskowski, V.D.

1981-11-01

317

Increasing productivity through Total Reuse Management (TRM)  

NASA Technical Reports Server (NTRS)

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

Schuler, M. P.

1991-01-01

318

Frustrated total internal reflection acoustic field sensor  

DOEpatents

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

Kallman, Jeffrey S. (Pleasanton, CA)

2000-01-01

319

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

320

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

321

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

322

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

323

Bioinspired total synthesis of gymnothelignan N.  

PubMed

Bioinspired total synthesis of gymnothelignan N was accomplished in 13 steps and 6.7% overall yield. The synthesis features a syn Evans aldol reaction, an intramolecular hydrogenative dehydration reaction, and a phenol oxidative dearomatization/Friedel-Crafts reaction, which provides a new plausible biosynthetic pathway for the gymnothelignans and other symbiotic members. Meanwhile, another tetrahydrofuran-type lignan beilschmin A was also synthesized. PMID:25103476

Li, Huilin; Zhang, Yuanyuan; Xie, Xingang; Ma, Haichen; Zhao, Changgui; Zhao, Gaoyuan; She, Xuegong

2014-09-01

324

Total Renewable Freshwater Supply By Country  

NSDL National Science Digital Library

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

325

Total Phallic Construction, Option to Gender Reassignment  

Microsoft Academic Search

\\u000a Total phallic construction was first accomplished by Borgoraz in Russia in 1936 (Borgoraz, 1936). He described a technique\\u000a of tubed abdominal flap which was transposed to the area of the penis by techniques of flap delay. A number of authors used\\u000a this technique with acceptable results. The phallus, so created, was insensible baculum dependent for rigidity, and often\\u000a did not

Gerald H. Jordan

326

Total Hip Joint Replacement Biotelemetry System  

NASA Technical Reports Server (NTRS)

The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.

Boreham, J. F.; Postal, R. B.; Luntz, R. A.

1981-01-01

327

Total knee arthroplasty: looks good, feels bad  

Microsoft Academic Search

Total knee arthroplasty has a high success rate but approximately 4%–5% of patients have fair to poor results and 1% of patients are extremely unhappy. With a complete work-up a diagnosis can usually be made to explain the patient’s symptoms and lead to an appropriate solution. In that small percentage of cases (1%) with unexplained pain or dysfunction, surgical intervention

James A D’Antonio

2003-01-01

328

Dextromethorphan and pain after total abdominal hysterectomy  

Microsoft Academic Search

Summary Dextromethorphan is an N-methyl-D-aspartate (NMDA) receptor antagonist which has been shown to inhibit the development of cutaneous secondary hyperalgesia after tissue trauma. We studied 60 ASA I-II patients undergoing total abdominal hysterectomy in a randomized, double-blind, placebo-controlled study. Patients received either dextromethorphan 27 mg cap- sules, two doses before operation and three doses in the first 24 h after

P. M. MCCONAGHY; P. MCSORLEY; W. MCCAUGHEY; W. I. CAMPBELL

1998-01-01

329

The benefits of total quality management.  

PubMed

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

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

2001-01-01

330

Plasma total-homocysteine in anorexia nervosa  

Microsoft Academic Search

Objective: The measurement of plasma total-homocysteine (tHcy) as a marker of folate and cobalamin status in patients with anorexia nervosa.Design: Plasma tHcy, folate, cobalamin and other determinats of tHcy of a random group of patients with anorexia nervosa were compared with our own reference values.Setting: The study was performed at the tertiary children's Hospital Sant Joan de Déu.Subjects: All the

D Moyano; MA Vilaseca; R Artuch; C Valls; N Lambruschini

1998-01-01

331

Press-fit condylar total knee arthroplasty  

Microsoft Academic Search

Between November 1984 and December 1987, 378 consecutive Press-Fit Condylar (PFC, Johnson & Johnson Professional, Raynham, MA) total knee arthroplasties were performed in 290 patients. The average age at surgery was 67 years (range, 22–91 years). The average follow-up period was 6.5 years (range, 5–9 years). Scoring was carried out according to the Knee Society scoring system. The average preoperative

Scott David Martin; Jacquelyn L. McManus; Richard D. Scott; Thomas S. Thornhill

1997-01-01

332

Total synthesis of insect antifeedant drimane sesquiterpenes  

Microsoft Academic Search

The investigations described in this thesis deal with the total synthesis of sesquiterpenes of the drimane family, named for their widespread occurrence in the stem bark of South American Drimys species. These compounds contain the bicyclofarnesol nucleus 1<\\/strong> , which is invariably oxidized at C-11 and\\/or C-12 and often at other sites as well (see figure 8.1).

B. J. M. Jansen

1993-01-01

333

TOTAL QUALITY MANAGEMENT AND SMALL BUSINESSES  

Microsoft Academic Search

Total Quality Management (TQM) for the past twenty years has revolutionized U.S. manufacturing, through a system based on continuous improvement, meeting customers' requirements, reducing rework, long-range thinking, increased employee involvement and teamwork, process redesign, competitive benchmarking, teambased problem-solving, constant measurement of results, and closer relationships with suppliers. (Ross, 1993) This article briefly reviews the effects of three behavioral influences: power,

Joseph G. Ormsby; Stephen F. Austin

334

Solar Total Energy at Sandia Labs  

Microsoft Academic Search

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

J. A. Leonard

1976-01-01

335

Bilateral piriformis syndrome after total hip arthroplasty  

Microsoft Academic Search

We present the case of a 39-year-old man with bilateral piriformis syndrome 4 and 6 years after two cementless total hip\\u000a arthroplasties, respectively. During surgical exploration, each sciatic nerve was found to be entrapped by a tense piriformis\\u000a muscle and hypertrophic posterior hip capsule. The sciatic-type pain was relieved after sectioning each piriformis muscle\\u000a with external neurolysis. This is the

Y. Uchio; U. Nishikawa; M. Ochi; N. Shu; K. Takata

1998-01-01

336

Determination of Total Cholesterol in Hypertriglyceridemic Serums  

Microsoft Academic Search

The determination of serum total cholesterol by a direct reaction involving a Trinder-type enzymic pathway can be severely hampered by the turbidity caused by excessive concentrations of triglyceride-rich lipoproteins such as very-low-density lipoproteins and chylomicrons. This paper describes a clarification procedure that effectively removes such turbidity by a process involving lipolysis of triglycerides and entrapment of the liberated nonesterified fatty

B. R. Morgan; J. D. Artiss; B. Zak

1998-01-01

337

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

338

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

339

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

340

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

341

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

342

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

343

Why Revision Total Hip Arthroplasty Fails  

PubMed Central

Current outcomes data on revision total hip arthroplasty focuses on specific implants and techniques rather than more general outcomes. We therefore examined a large consecutive series of failed THAs undergoing revision to determine if survivorship and modes of failure differ in comparison to the current data. We retrospectively reviewed the medical records of 1100 revision THAs. The minimum followup was 2 years (mean, 6 years; range, 0–20.4 years). Eighty-seven percent of revision total hips required no further surgery; however, 141 hips (13%) underwent a second revision at a mean of 3.7 years (range, 0.025–15.9 years). Seventy percent (98 hips) had a second revision for a diagnosis different from that of their index revision, while 30% (43 hips) had a second revision for the same diagnosis. The most common reasons for failure were instability (49 of 141 hips, 35%), aseptic loosening (42 of 141 hips, 30%), osteolysis and/or wear (17 of 141 hips, 12%), infection (17 of 141 hips, 12%), miscellaneous (13 of 141 hips, 9%), and periprosthetic fracture (three of 141 hips, 2%). Survivorship for revision total hip arthroplasty using second revision as endpoint was 82% at 10 years. Aseptic loosening and instability accounted for 65% of these failures. Level of Evidence: Level IV, therapeutic (retrospective) study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18975043

Fehring, Thomas K.; Griffin, William L.; Odum, Susan M.; Masonis, John L.

2008-01-01

344

A Global Climatology of Total Ozone from the Nimbus 7 Total Ozone Mapping Spectrometer  

Microsoft Academic Search

A global climatology of total column ozone has been computed from 4 years of daily observations by the total ozone mapping spectrometer aboard the Nimbus 7 polar-orbiting satellite. Observations were made at local noon; no observations are available in polar regions during the polar night. The orbital data have been area averaged onto a regular 5 ű by 5 ű

Kenneth P. Bowman; Arlin J. Krueger

1985-01-01

345

Introduction of total knee arthroplasty in Lithuania  

PubMed Central

Background and purpose We have previously reported that the first 10 years of hip arthroplasty in Lithuania resulted in a higher cumulative revision rate than that observed in Sweden. We thus compared the corresponding results after introduaction of total knee replacement in Lithuania. Methods The 10-year revision rate for the first 595 primary ScanKnee arthroplasties inserted in Klaipeda, Lithuania, was compared to that for the first 1,280 ScanKnee primary arthroplasties inserted in Sweden. As in the hip replacement study, only patients with osteoarthritis (OA) were included. Primary knee arthroplasties without patellar resurfacing were included, and the endpoint was revision for any reason other than addition of a patellar component. Results We found that the cumulative revision rate was not statistically significantly different between the groups. The revision pattern was different, however, and we observed 24 isolated patellar component additions in Sweden, but none in Klaipeda. Interpretation Contrary to the results of our previous hip arthroplasty study, the cumulative revision rate after total knee arthroplasty was similar in the two groups. This suggests that compared to hip arthroplasty, the outcome of total knee arthroplasty was less dependent on surgical experience. The large difference regarding isolated patellar component additions may be explained by long-term accumulation of severe OA cases in Lithuania. To patients subject to a newly introduced surgical treatment offering great improvement in quality of life, patellofemoral pain may be a minor problem. Furthermore, patellar problems may not have seemed particularly relevant for the surgeons, considering the disability of other patients waiting to be treated. PMID:19297790

Stucinskas, Justinas; Robertsson, Otto; Wingstrand, Hans

2009-01-01

346

Total synthesis and structural revision of engelhardione  

PubMed Central

The total synthesis of the macrocyclic natural product engelhardione is reported. This effort led to the structural revision of the published structure of engelhardione to that of pterocarine. The revision reflects the change of the substitution pattern of one phenyl ether ring from the meta to the para position. To confirm, pterocarine (2) and its close regioisomer 3 were subsequently synthesized for comparison. Moreover, to the best of our knowledge, our synthesis of 1 represents the first example of a 14-membered macrocyclic diarylheptanoid with a meta-meta substitution pattern at the diphenyl ether moiety. PMID:21927512

Shen, Li; Sun, Dianqing

2011-01-01

347

Total Talar Extrusion without Soft Tissue Attachments  

PubMed Central

Total talar extrusion without a soft tissue attachment is an extremely rare injury and is rarely reported. Appropriate treatment remains controversial. We describe the long-term outcomes of two patients who had complete talar extrusion without remaining soft tissue attachment treated with arthrodesis. Both of our patients had complications such as infection and progressive osteolysis. We suggest reimplantation of the extruded talus after thorough debridement as soon as possible as a reasonable option unless the talus is contaminated or missing, because an open wound may arise from inside to outside. PMID:24900908

Lee, Ho Seong; Chung, Hyun Wook

2014-01-01

348

Total body nitrogen analysis. [neutron activation analysis  

NASA Technical Reports Server (NTRS)

Studies of two potential in vivo neutron activation methods for determining total and partial body nitrogen in animals and humans are described. A method using the CO-11 in the expired air as a measure of nitrogen content was found to be adequate for small animals such as rats, but inadequate for human measurements due to a slow excretion rate. Studies on the method of measuring the induced N-13 in the body show that with further development, this method should be adequate for measuring muscle mass changes occurring in animals or humans during space flight.

Palmer, H. E.

1975-01-01

349

Total solar house description and performance  

SciTech Connect

The initial attempt to apply the Total Solar concept to a residence in the Philadelphia, Pennsylvania, area is described. A very large storage capacity has made it possible to use only solar energy for meeting the heating, cooling and hot water needs for the entire year, with a parasitic power penalty of about 3500 kWh. Winter temperatures were maintained at 68/sup 0/F with 60/sup 0/F night setback, summer at 76/sup 0/F. Occupant intervention was negligible and passive overheat was minimized. The extra cost for the system, approximately $30,000 is readily amortized by the savings in purchased energy.

Starobin, L. (Univ. of Pennsylvania, Philadelphia); Starobin, J.

1981-01-01

350

Catalytic asymmetric total synthesis of (+)-caprazol.  

PubMed

Catalytic asymmetric total synthesis of caprazol, a lipo-nucleoside antibiotic, has been accomplished employing two of the stereoselective C-C bond forming reactions as key transformations. The stereochemistries of the ?-hydroxy-?-aminoester moiety at the juncture of the uridine part and diazepanone part, and of the ?-hydroxy-?-amino acid moiety embedded in the diazepanone system, were constructed using a diastereoselective isocyanoacetate aldol reaction (dr = 88:12) and an enantioselective anti-nitroaldol reaction catalyzed by a Nd/Na-chiral amide ligand (dr = 12:1, 95% ee), respectively. PMID:24897294

Gopinath, Purushothaman; Wang, Lu; Abe, Hikaru; Ravi, Gandamala; Masuda, Takashi; Watanabe, Takumi; Shibasaki, Masakatsu

2014-06-20

351

Total synthesis of anticoagulant pentasaccharide fondaparinux.  

PubMed

The anticoagulant pentasaccharide fondaparinux was synthesized using an improved and optimized synthetic strategy including a convergent [3+2] coupling approach, orthogonal protecting groups and various glycosyl donors. The new methods of glycosylation were also used for controlling the stereochemical configuration and improving the yield of the glycosylation. In addition, HPLC and NMR methods to monitor the process of total synthesis of fondaparinux were employed. This work provides a comprehensive elaboration for the synthesis and analysis of fondaparinux based on related literature, as well as abundant information for the synthesis of heparin-like oligosaccharides. PMID:24729477

Li, Tiehai; Ye, Hui; Cao, Xuefeng; Wang, Jiajia; Liu, Yonghui; Zhou, Lifei; Liu, Qiang; Wang, Wenjun; Shen, Jie; Zhao, Wei; Wang, Peng

2014-05-01

352

Security Systems Consideration: A Total Security Approach  

NASA Astrophysics Data System (ADS)

The "safety" problem for protection systems is to determine in a given situation whether a subject can acquire a particular right to an object. Security and audit operation face the process of securing the application on computing and network environment; however, storage security has been somewhat overlooked due to other security solutions. This paper identifies issues for data security, threats and attacks, summarizes security concepts and relationships, and also describes storage security strategies. It concludes with recommended storage security plan for a total security solution.

Margariti, S. V.; Meletiou, G.; Stergiou, E.; Vasiliadis, D. C.; Rizos, G. E.

2007-12-01

353

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

PubMed Central

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 agents. We discuss (1) the application of an Evans’ Cu-catalyzed aldol addition reaction using a strained cyclopropyl ketenethioacetal, (2) an efficient enyne ring-closing metathesis (EYRCM) cascade reaction in a challenging setting, (3) the reagent IPNBSH for a late stage reductive allylic transposition reaction, and (4) the final RCM/dehydrogenation sequence for the formation of (?)-acylfulvene (1) and (?)-irofulven (2). PMID:19938810

Siegel, Dustin S.; Piizzi, Grazia; Piersanti, Giovanni; Movassaghi, Mohammad

2009-01-01

354

First total synthesis of antimitotic compound, (+)-phomopsidin.  

PubMed

[reaction: see text] The first total synthesis of (+)-phomopsidin has been achieved via a diastereoselective transannular Diels-Alder (TADA) reaction. Key steps in the synthesis include diastereoselective ynone reduction with (-)-alpha-pinene and 9-BBN, macrocyclization by E-selective intramolecular Horner-Wadsworth-Emmons (HWE) reaction, as well as carbometalation under Wipf's conditions, followed by HWE reaction at low temperature to selectively construct the (E)-1-methylpropenyl and (1E,2E)-4-carboxy-1,3-butadienyl substituents. PMID:14961621

Suzuki, Takahiro; Usui, Kenji; Miyake, Yoshiharu; Namikoshi, Michio; Nakada, Masahisa

2004-02-19

355

The INBONE II Total Ankle System.  

PubMed

The INBONE II Total Ankle System consists of modular intramedullary stem pieces that are supported by a tibial tray spanning the anterior and posterior tibial cortices. The original INBONE talar component was broad and saddle-shaped whereas the INBONE II design is sulcus-shaped. Both talar components have a modular stem; the INBONE II design also has 2 anterior pegs. This article provides a detailed review of the surgical technique for implantation of the INBONE II and perioperative insight into patient care. PMID:23164439

Abicht, Bradley P; Roukis, Thomas S

2013-01-01

356

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

PubMed

The first total synthesis of (+/-)-ingenol has been achieved. The key features of the synthesis include the use of a highly diastereoselective Michael reaction to fix the C-11 methyl stereochemistry and the incorporation of the dimethylcyclopropane via diastereoselective carbene addition to the Delta13,14 olefin. The intramolecular dioxenone photoaddition-fragmentation sequence leads to the establishment of the critical C-8/C-10 trans intrabridgehead stereochemistry, a central challenge in the synthesis of ingenanes. The completion of the synthesis proceeds using the C-6alpha hydroxymethyl group as the sole handle for oxidation of seven contiguous carbon centers. PMID:12175229

Winkler, Jeffrey D; Rouse, Meagan B; Greaney, Michael F; Harrison, Sean J; Jeon, Yoon T

2002-08-21

357

Vaginal mass following uncemented total hip arthroplasty  

PubMed Central

A 53-year-old woman developed a vaginal mass following an uncemented total hip arthroplasty. The mass was in direct communication with the hip through an acetabular medial wall defect after loosening of the acetabular component. The mass formation was caused simultaneously by changes secondary to polyethylene wear, a tiny delamination of the porous titanium mesh coating and a broken antirotational tab on the acetabular cup, all of which may have served as sources of metal particles. A careful evaluation of the patient's history, symptoms, X-ray findings and computed tomography scans should always be performed to ensure accurate diagnosis.

Shin, Young-Soo; Jung, Tae-Wan; Han, Seung-Beom

2014-01-01

358

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; Skorska, Malgorzata; Fundowicz, Dorota

2013-01-01

359

MFR total ozone grid point data  

SciTech Connect

Multichannel filter radiometers (MFR) on four satellites of the Defense Meteorological Satellite Program (DMSP) measured infrared radiances in 16 channels including the 9.6 ..mu..m ozone band. The quality of these radiance data and their intercomparisons are discussed. A data base containing the calibrated radiance data and total ozone is archived on 108 magnetic tapes of 6250 bpi density at the National Space Science Data Center (NSSDC), Goddard Space Flight Center, Greenbelt, Maryland. These tapes were written in a packed binary form and are compatible only with a VAX 11/780 series computer.

Ellis, J.S.; Lovill, J.E.

1983-08-01

360

Free cooling: A total HVAC design concept  

NASA Astrophysics Data System (ADS)

The free cooling concept which relates to system of air conditioning for mild, medium altitude and/or dry, hot climatic areas, whereby chillers and refrigerated cooling may be totally eliminated was examined. Substance of system comprises: (1) precooling of structure overnight; (2) direct exhausting of heat from light fitting; and (3) an improved process of evaporative cooling. Impact is that air conditioning for small and large new buildings may be facilitated at low capital costs with substantially reduces year round energy requirements. Standby chillers may be provided for depending on area and building characteristics.

Janeke, C. E.

361

Total Body Irradiation (TBI) in Pediatric Patients  

Microsoft Academic Search

\\u000a Abstract\\u000a \\u000a \\u000a Purpose:\\u000a   To retrospectively analyze patient characteristics, treatment, and treatment outcome of pediatric patients with hematologic\\u000a diseases treated with total body irradiation (TBI) between 1978 and 2006.\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a Patients and Methods:\\u000a   32 pediatric patients were referred to the Department of Radiation-Oncology at the University of Zurich\\u000a for TBI. Records of regular follow-up of 28 patients were available for review. Patient characteristics

Claudia Linsenmeier; Daniel Thoennessen; Laura Negretti; Jean-Pierre Bourquin; Tino Streller; Urs Martin Lütolf; Susanne Oertel

2010-01-01

362

Vaginal mass following uncemented total hip arthroplasty.  

PubMed

A 53-year-old woman developed a vaginal mass following an uncemented total hip arthroplasty. The mass was in direct communication with the hip through an acetabular medial wall defect after loosening of the acetabular component. The mass formation was caused simultaneously by changes secondary to polyethylene wear, a tiny delamination of the porous titanium mesh coating and a broken antirotational tab on the acetabular cup, all of which may have served as sources of metal particles. A careful evaluation of the patient's history, symptoms, X-ray findings and computed tomography scans should always be performed to ensure accurate diagnosis. PMID:25404779

Shin, Young-Soo; Jung, Tae-Wan; Han, Seung-Beom

2014-11-01

363

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

364

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

365

Near-total absence of the cerebellum.  

PubMed

We report five cases of near-total absence of the cerebellum with accompanying pontine hypoplasia. The cerebellar remnant in each case comprised only antero-superior masses, the posterior fossa being otherwise fluid filled. Three of these patients, two teenagers and an infant, presented a fairly consistent clinical and neuroradiological phenotype, and a few similar cases are recorded in the literature. The cerebellar remnant was irregular and asymmetrical, and no ventral pontine prominence was discernible. In at least the older two, cerebellar motor functions were not greatly compromised, and intellectual handicap was of a mild degree. We propose that these cases represent a distinct entity of "near-total absence of the cerebellum with flat ventral pons, and relatively mild clinical affection". All cases have been sporadic, implying that the risk of recurrence within a family may be low. Quite different clinical pictures, of considerably greater severity, are demonstrated in the remaining two cases. One had pontocerebellar hypoplasia type 2, while the other had a complex cerebellar and cerebral malformation. PMID:11414645

Gardner, R J; Coleman, L T; Mitchell, L A; Smith, L J; Harvey, A S; Scheffer, I E; Storey, E; Nowotny, M J; Sloane, R A; Lubitz, L

2001-04-01

366

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

367

Methods development for total organic carbon accountability  

NASA Technical Reports Server (NTRS)

This report describes the efforts completed during the contract period beginning November 1, 1990 and ending April 30, 1991. Samples of product hygiene and potable water from WRT 3A were supplied by NASA/MSFC prior to contract award on July 24, 1990. Humidity condensate samples were supplied on August 3, 1990. During the course of this contract chemical analyses were performed on these samples to qualitatively determine specific components comprising, the measured organic carbon concentration. In addition, these samples and known standard solutions were used to identify and develop methodology useful to future comprehensive characterization of similar samples. Standard analyses including pH, conductivity, and total organic carbon (TOC) were conducted. Colorimetric and enzyme linked assays for total protein, bile acid, B-hydroxybutyric acid, methylene blue active substances (MBAS), urea nitrogen, ammonia, and glucose were also performed. Gas chromatographic procedures for non-volatile fatty acids and EPA priority pollutants were also performed. Liquid chromatography was used to screen for non-volatile, water soluble compounds not amenable to GC techniques. Methods development efforts were initiated to separate and quantitate certain chemical classes not classically analyzed in water and wastewater samples. These included carbohydrates, organic acids, and amino acids. Finally, efforts were initiated to identify useful concentration techniques to enhance detection limits and recovery of non-volatile, water soluble compounds.

Benson, Brian L.; Kilgore, Melvin V., Jr.

1991-01-01

368

Particle-enhanced total internal reflectance fluorescenceź  

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

369

Total knee replacement with natural rollback.  

PubMed

A novel class of total knee replacement (AEQUOS G1) is introduced which features a unique design of the articular surfaces. Based on the anatomy of the human knee and differing from all other prostheses, the lateral tibial "plateau" is convexly curved and the lateral femoral condyle is posteriorly shifted in relation to the medial femoral condyle. Under compressive forces the configuration of the articular surfaces of human knees constrains the relative motion of femur and tibia in flexion/extension. This constrained motion is equivalent to that of a four-bar linkage, the virtual 4 pivots of which are given by the centres of curvature of the articulating surfaces. The dimensions of the four-bar linkage were optimized to the effect that constrained motion of the total knee replacement (TKR) follows the flexional motion of the human knee in close approximation, particularly during gait. In pilot studies lateral X-ray pictures have demonstrated that AEQUOS G1 can feature the natural rollback in vivo. Rollback relieves the load of the patello-femoral joint and minimizes retropatellar pressure. This mechanism should reduce the prevalence of anterior knee pain. The articulating surfaces roll predominantly in the stance phase. Consequently sliding friction is replaced by the lesser rolling friction under load. Producing rollback should minimize material wear due to friction and maximize the lifetime of the prosthesis. To definitely confirm these theses one has to wait for the long term results. PMID:21493053

Wachowski, Martin Michael; Walde, Tim Alexander; Balcarek, Peter; Schüttrumpf, Jan Philipp; Frosch, Stephan; Stauffenberg, Caspar; Frosch, Karl-Heinz; Fiedler, Christoph; Fanghänel, Jochen; Kubein-Meesenburg, Dietmar; Nägerl, Hans

2012-03-20

370

Esophagojejunostomy after total gastrectomy for caustic injuries.  

PubMed

The objective of the study was to compare outcomes of emergency esophagogastrectomy (EGT) and total gastrectomy with immediate esophagojejunostomy (EJ) in patients with full-thickness caustic necrosis of the stomach and mild esophageal injuries. After caustic ingestion, optimal management of the esophageal remnant following removal of the necrotic stomach remains a matter of debate. Between 1987 and 2012, 26 patients (men 38%, median age 44 years) with isolated transmural gastric necrosis underwent EGT (n = 14) or EJ (n = 12). Early and long-term outcomes of both groups were compared. The groups were similar regarding age (P = 0.66), gender (0.24), and severity of esophageal involvement. Functional success was defined as nutritional autonomy after removal of the jejunostomy and tracheotomy tubes. Emergency morbidity (67% vs. 64%, P = 0.80), mortality (17% vs. 7%, P = 0.58), and reoperation rates (25% vs.14%, P = 0.63) were similar after EJ and EGT. One patient (8%) experienced EJ leakage. One patient in the EJ group and 13 patients in the EGT group underwent esophageal reconstruction (P < 0.0001). Aggregate in hospital length of stay was significantly longer in patients who underwent EGT (median 83 [33-201] vs. 36 [10-82] days, P = 0.001). Functional success after EJ and EGT was similar (90% vs.69%, P = 0.34). Immediate EJ can be safely performed after total gastrectomy for caustic injuries and reduces the need of further esophageal reconstruction. PMID:23621347

Chirica, M; Kraemer, A; Petrascu, E; Vuarnesson, H; Pariente, B; Halimi, B; Munoz-Bongrand, N; Sarfati, E; Cattan, P

2014-01-01

371

Deep infection in total hip arthroplasty  

PubMed Central

Objective To report on a 30-year prospective study of deep infection in 1993 consecutive total hip arthroplasties performed by a single surgeon. Methods The relations of numerous variables to the incidence of deep infection were studied. Results The cumulative infection rate after the index total hip arthroplasties rose from 0.8% at 2 years to 1.4% at 20 years; 9.6% of the index operations required further surgery. When infections attributed to these secondary procedures were included, the infection rate rose from 0.9% at 2 years to 2% at 20 years. Although the usual variables increased the incidence of infection, the significant and most precise predictors of infection were radiologic diagnoses of upper pole grade III and protrusio acetabuli, an elevated erythrocyte sedimentation rate, alcoholism and units of blood transfused. Conclusion From 2–20 years, the incidence of deep infection doubled. Preoperative recognition of the first 4 risk factors permits the use of additional prophylactic measures. Spinal or epidural anesthesia reduced the units of blood transfused (the fifth risk factor) and, hence, the risk of infection. Although most deep infections are seeded while the wound is open, there are many possible postoperative causes. In this study, fewer than one-third of the infections that presented after 2 years were related to hematogenous spread. The efficacy of clean air technology was supported, and it is recommended that all measures that may reduce the incidence of deep infection be employed. PMID:18377751

Hamilton, Henry; Jamieson, John

2008-01-01

372

Planned totally extraperitoneal laparoscopic Spigelian hernia repair.  

PubMed

A Spigelian hernia is a congenital defect in the tranversus aponeurosis fascia. Traditionally, an open anterior hernioplasty was used to repair these defects. Recently, laparoscopic approaches have been described. This report describes the first application of the totally extraperitoneal laparoscopic approach to a planned repair of a Spigelian hernia. The patient was a 62-year-old white female with a reducible left lower quadrant anterior abdominal wall bulge consistent with a Spigelian hernia. At the time of surgery, we exposed the posterior rectus fascia and modified our extraperitoneal inguinal hernia technique by passing the balloon dissector in a more lateral orientation. This created a unilateral preperitoneal space with adequate room for dissection and mesh fixation. The Spigelian defect was easily identified. Its preperitoneal fat contents were reduced, and a 5-mm laparoscopic tacking device was used to secure a piece of prolene mesh. The patient was discharged home with no complications. Placement of the mesh in the preperitoneal space avoids direct interaction of the mesh prosthesis and the intraperitoneal viscera. In conclusion, we find that a laparoscopic totally extraperitoneal approach is technically feasible and advantageous when a Spigelian hernia is diagnosed preoperatively. PMID:11967699

Tarnoff, M; Rosen, M; Brody, F

2002-02-01

373

Low frequency oscillations in total ozone measurements  

NASA Technical Reports Server (NTRS)

Low frequency oscillations with periods of approximately one to two months are found in eight years of global grids of total ozone data from the Total Ozone Mapping Spectrometer (TOMS) satellite instrument. The low frequency oscillations corroborate earlier analyses based on four years of data. In addition, both annual and seasonal one-point correlation maps based on the 8-year TOMS data are presented. The results clearly show a standing dipole in ozone perturbations, oscillating with 35 to 50 day periods over the equatorial Indian Ocean-west Pacific region. This contrasts with the eastward moving dipole reported in other data sets. The standing ozone dipole appears to be a dynamical feature associated with vertical atmospheric motions. Consistent with prior analyses based on lower stratospheric temperature fields, large-scale standing patterns are also found in the extratropics of both hemispheres, correlated with ozone fluctuations over the equatorial west Pacific. In the Northern Hemisphere, a standing pattern is observed extending from the tropical Indian Ocean to the north Pacific, across North America, and down to the equatorial Atlantic Ocean region. This feature is most pronounced in the NH summer.

Gao, X. H.; Stanford, J. L.

1989-01-01

374

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...

375

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

Code of Federal Regulations, 2010 CFR

...may or may not be permanent. Total ratings will not be assigned, generally, for temporary exacerbations or acute infectious diseases except where specifically prescribed by the schedule. (2) Schedule for rating disabilities....

2010-07-01

376

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

Code of Federal Regulations, 2011 CFR

...may or may not be permanent. Total ratings will not be assigned, generally, for temporary exacerbations or acute infectious diseases except where specifically prescribed by the schedule. (2) Schedule for rating disabilities....

2011-07-01

377

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

Code of Federal Regulations, 2013 CFR

...may or may not be permanent. Total ratings will not be assigned, generally, for temporary exacerbations or acute infectious diseases except where specifically prescribed by the schedule. (2) Schedule for rating disabilities....

2013-07-01

378

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

Code of Federal Regulations, 2012 CFR

...may or may not be permanent. Total ratings will not be assigned, generally, for temporary exacerbations or acute infectious diseases except where specifically prescribed by the schedule. (2) Schedule for rating disabilities....

2012-07-01

379

Tracer monitored titrations: measurement of total alkalinity.  

PubMed

We introduce a new titration methodology, tracer monitored titration (TMT), in which analyses are free of volumetric and gravimetric measurements and insensitive to pump precision and reproducibility. Spectrophotometric monitoring of titrant dilution, rather than volume increment, lays the burden of analytical performance solely on the spectrophotometer. In the method described here, the titrant is a standardized mixture of acid-base indicator and strong acid. Dilution of a pulse of titrant in a titration vessel is tracked using the total indicator concentration measured spectrophotometrically. The concentrations of reacted and unreacted indicator species, derived from Beer's law, are used to calculate the relative proportions of titrant and sample in addition to the equilibrium position (pH) of the titration mixture. Because the method does not require volumetric or gravimetric additions of titrant, simple low-precision pumps can be used. Here, we demonstrate application of TMT for analysis of total alkalinity (A(T)). High-precision, high-accuracy seawater A(T) measurements are crucial for understanding, for example, the marine CaCO3 budget and saturation state, anthropogenic CO2 penetration into the oceans, calcareous phytoplankton blooms, and coral reef dynamics. We present data from 286 titrations on three types of total alkalinity standards: Na2CO3 in 0.7 mol kg x soln(-1) NaCl, NaOH in 0.7 mol kg x soln(-1) NaCl, and a seawater Certified Reference Material (CRM). Based on Na2CO3 standards, the accuracy and precision are +/-0.2 and +/-0.1% (4 and 2 micromol kg x soln(-1) for A(T) approximately 2100-2500 micromol kg x soln(-1), n = 242), using low-precision solenoid pumps to introduce sample and titrant. Similar accuracy and precision were found for analyses run 42 days after the initial experiments. Excellent performance is achieved by optimizing the spectrophotometric detection system and relying upon basic chemical thermodynamics for calculating the equivalence point. Although applied to acid-base titrations in this paper, the approach should be generally applicable to other types of titrations. PMID:16536416

Martz, Todd R; Dickson, Andrew G; DeGrandpre, Michael D

2006-03-15

380

Total shoulder arthroplasty in dislocation arthropathy  

PubMed Central

Follow-up examinations of 45 patients who received shoulder arthroplasty for osteoarthritis following shoulder instability were conducted after 44 months. The goal of this study was to describe the clinical findings associated with advanced glenohumeral arthritis due to shoulder instability and instability repairs and to present the clinical results and complications of treating this with shoulder arthroplasty. The weighted average Constant score increased significantly from 49.4 to 81.3 points. There was no significant difference in the type of arthroplasty with 35 cases of total shoulder replacements and ten cases of hemiarthoplasty. The rate of complications was 40% (18/45 patients) with 20% (9/45 patients) requiring an operative revision. Patients with arthritis after instability repair showed great improvement in all qualities of the Constant score. Nonetheless, further analyses are required to determine why such a relatively young group of patients showed high complication rates. PMID:20041242

Magosch, Petra; Mauermann, Eckhard; Lichtenberg, Sven; Habermeyer, Peter

2009-01-01

381

SERC Pedagogic Library: Total Internal Reflection  

NSDL National Science Digital Library

This item is a research-based lesson plan on the topic of total internal reflection (TIR), designed for use in introductory physics classrooms. It is aligned with the Interactive Lecture pedagogic approach. The purpose of the lesson is to help students apply Snell's Law to discover circumstances under which the TIR phenomenon occurs. This resource was peer reviewed by the SERC Pedagogic team (Science Education Resource Center). **NOTE: This lesson requires use of a refraction tank, available at science supply companies for $80-100. This item is part of the SERC Pedagogic Library, a collaboration between SERC Pedagogic Service Project and ComPADRE. SEE RELATED ITEMS on this page for a link to the full collection.

2009-05-22

382

A challenging case of total phalloplasty  

PubMed Central

Plastic surgery continues to maintain a prominent presence in the evolution of male genital reconstruction. In this case report, we are presenting a case of post-electric burn with a total loss of penis. Sustaining other major injuries following an electric burn with loss of right upper limb and extensive tissue damage to left upper limb, abdomen and both thighs, this young male patient was initially managed from life-threatening problems. With many options closed following a major electric burn and its acute management, penile and urethral reconstruction was a unique and a great challenge in this patient. Heeding to the patient's wish of male pattern micturition, we had performed a successful reconstruction of urethra and entire phallus with groin flap. PMID:22754174

Sridhar, R; Jayaraman, V.

2012-01-01

383

Total synthesis of marine eicosanoid (-)-hybridalactone.  

PubMed

(-)-Hybridalactone (1) is a marine eicosanoid isolated from the red alga Laurencia hybrida. This natural product contains cyclopropane, cyclopentane, 13-membered macrolactone and epoxide ring systems incorporating seven stereogenic centers. Moreover, this compound has an acid-labile skipped Z,Z-diene motif. In this paper, we report on the total synthesis of (-)-hybridalactone (1). The unique eicosanoid (-)-hybridalactone (1) was synthesized starting from optically active ?-butyrolactone 2 in a linear sequence comprising 21 steps with an overall yield of 21.9%. A key step in the synthesis of (-)-hybridalactone (1) is the methyl phenylsulfonylacetate-mediated one-pot synthesis of the cis-cyclopropane-?-lactone derivative. This reaction provided an efficient and stereoselective access to cis-cyclopropane-?-lactone 12. Further elaboration of the latter compounds through desulfonylation, epoxidation, oxidation, Wittig olefination and Shiina macrolactonization afforded (-)-hybridalactone. PMID:22965557

Ota, Koichiro; Sugata, Naoto; Ohshiro, Yoshihiko; Kawashima, Etsuko; Miyaoka, Hiroaki

2012-10-15

384

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.

1997-01-01

385

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

386

Total electron content measurements in ionospheric physics  

NASA Astrophysics Data System (ADS)

With the advent of modern global networks of dual-frequency Global Positioning System (GPS), total electron content (TEC) measurements along slant paths connecting GPS receivers and satellites at 22,000 km have become the largest data set available to ionospheric scientists. The TEC can be calculated from the time and phase delay in the GPS signal using the GPS Toolkit, but an unknown bias will remain. In addition, UHF/VHF radio beacons on board low-Earth-orbiting satellites can also be used to measure the electron content. However, the TEC measurements are obtained by integrating TEC differences between slant paths, but also contain biases. It is often necessary to use data assimilative algorithms like the Ionospheric Data Assimilation Three-Dimensional (IDA3D), and to treat both GPS- and LEO-beacon TEC measurements as relative data in order to conduct ionospheric studies.

Garner, T. W.; Gaussiran, T. L., II; Tolman, B. W.; Harris, R. B.; Calfas, R. S.; Gallagher, H.

2008-08-01

387

Revision total hip arthroplasty in Jehovah's Witnesses.  

PubMed

Revision total hip arthroplasty (THA) is associated with greater blood loss than primary THA. Jehovah's Witnesses will not accept transfusions of blood or blood products and are thus at an increased risk for complications due to perioperative anemia. The purpose of this study was to report the clinical outcomes, radiographic outcomes, morbidity, and mortality of Jehovah's Witnesses who were medically optimized and underwent revision THA. Databases from 2 institutions were reviewed to identify 10 patients (11 THAs) who were Jehovah's Witnesses undergoing revision THA with a minimum 24-month follow-up. At most recent follow-up, all patients were doing well clinically, with Harris Hip Scores greater than 80 points. Radiographic evaluation demonstrated well-positioned components and no progressive radioluciencies. No major perioperative medical or surgical complications occurred in patients undergoing THA. Revision THA for aseptic causes results in good clinical outcomes in patients who are preoperatively optimized before undergoing surgery. PMID:22868597

Harwin, Steven F; Pivec, Robert; Johnson, Aaron J; Naziri, Qais; Mont, Michael A

2012-08-01

388

Construction model for total variation regularization parameter.  

PubMed

Image denoising is important for high-quality imaging in adaptive optics. Richardson-Lucy deconvolution with total variation(TV) regularization is commonly used in image denoising. The selection of TV regularization parameter is an essential issue, yet no systematic approach has been proposed. A construction model for TV regularization parameter is proposed in this paper. It consists of four fundamental elements, the properties of which are analyzed in details. The proposed model bears generality, making it apply to different image recovery scenarios. It can achieve effective spatially adaptive image recovery, which is reflected in both noise suppression and edge preservation. Simulations are provided as validation of recovery and demonstration of convergence speed and relative mean-square error. PMID:24921752

Gong, Guanghua; Zhang, Hongming; Yao, Minyu

2014-05-01

389

Use of ceramics in total hip replacement.  

PubMed

Ceramics have been used as a bearing surface in total hip arthroplasty (THA) for more than 30 years. Properties of this material which make it particularly attractive for this application include its hardness, high compression strength, and excellent wettability. The low incidence of biologically significant particle generation and clinically significant osteolysis with the use of ceramics in THA reflects these properties. However, low fracture toughness and linear elastic behavior demonstrated by ceramic make it prone to breakage under stress. Improvements in the processing of ceramic as well as advances in engineering of head-neck articulations and liner design have led to an overall decrease in the incidence of ceramic fracture and dislocation. This article reviews the science behind the use of ceramics in THA, the clinical results of ceramics in THA, including complications unique to this bearing surface, and future directions for the application of ceramics in THA. PMID:18284905

Lang, Jason E; Whiddon, David R; Smith, Eric L; Salyapongse, Aaron K

2008-01-01

390

Patellar meniscus in total knee arthroplasty.  

PubMed

Twenty-four clinically successful, autopsy retrieved porous-coated anatomic total knee arthroplasty (TKA) specimens were evaluated to determine the structure and function of the patellar meniscus. Mean implant duration was 76 months (range: 11-135 months). Histological examination showed the patellar meniscus to be composed of dense fibrous tissue with scattered regions of chronic granulomatous response to polyethylene debris. Patellar wear and polyethylene exposed patellar surface area were correlated with implant duration (r = 0.47, P = .03; r = 0.52, P = .06). Postoperative patellar tilt was also associated with patellar component wear (r = 0.64, P = .03). No other clinical measures were significantly associated with patellar wear or exposed surface area. Additional research is needed to determine what role, if any, the patellar meniscus plays in TKA outcomes. PMID:17486906

Lavernia, Carlos J; Sheldon, Daniel A; Hernández, Victor H; D'Apuzzo, Michele R; Lee, David J; Krackow, Kenneth A; Hungerford, David S

2007-04-01

391

Avoiding patellar complications in total knee replacement.  

PubMed

Patellofemoral complications are common after total knee replacement (TKR). Leaving the patellar unsurfaced after TKR may lead to complications such as anterior knee pain, and re-operation to surface it. Complications after patellar resurfacing include patellar fracture, aseptic loosening, patellar instability, polyethylene wear, patellar clunk and osteonecrosis. Historically, patellar complications account for one of the larger proportions of causes of failure in TKR, however, with contemporary implant designs, complication rates have decreased. Most remaining failures relate to patellofemoral tracking. Understanding the causes of patellofemoral maltracking is essential to prevent these complications as well as manage them when they occur. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):84-6. PMID:25381415

Russell, R D; Huo, M H; Jones, R E

2014-11-01

392

Total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine.  

PubMed

A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo[1,2-a]azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-?-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12. PMID:22084978

Chen, Zhi-Hua; Chen, Zhi-Min; Zhang, Yong-Qiang; Tu, Yong-Qiang; Zhang, Fu-Min

2011-12-16

393

Total Ore Processing Integration and Management  

SciTech Connect

This report outlines the technical progress achieved for project DE-FC26-03NT41785 (Total Ore Processing Integration and Management) during the period 01 July through 30 September of 2005. This ninth quarterly report discusses the activities of the project team during the period 1 July through 30 September 2005. Richard Gertsch's unexpected death due to natural causes while in Minnesota to work on this project has temporarily slowed progress. Statistical analysis of the Minntac Mine data set for late 2004 is continuing. Preliminary results raised several questions that could be amenable to further study. Detailed geotechnical characterization is being applied to improve the predictability of mill and agglomerator performance at Hibtac Mine.

Leslie Gertsch; Richard Gertsch

2006-01-30

394

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

395

Total Monte Carlo evaluation for dose calculations.  

PubMed

Total Monte Carlo (TMC) is a method to propagate nuclear data (ND) uncertainties in transport codes, by using a large set of ND files, which covers the ND uncertainty. The transport code is run multiple times, each time with a unique ND file, and the result is a distribution of the investigated parameter, e.g. dose, where the width of the distribution is interpreted as the uncertainty due to ND. Until recently, this was computer intensive, but with a new development, fast TMC, more applications are accessible. The aim of this work is to test the fast TMC methodology on a dosimetry application and to propagate the (56)Fe uncertainties on the predictions of the dose outside a proposed 14-MeV neutron facility. The uncertainty was found to be 4.2 %. This can be considered small; however, this cannot be generalised to all dosimetry applications and so ND uncertainties should routinely be included in most dosimetry modelling. PMID:24277871

Sjöstrand, H; Alhassan, E; Conroy, S; Duan, J; Hellesen, C; Pomp, S; Osterlund, M; Koning, A; Rochman, D

2014-10-01

396

DVT prophylaxis in total joint reconstruction.  

PubMed

Deep venous thrombosis (DVT) is the end result of a complex interaction of events including the activation of the clotting cascade in conjunction with platelet aggregation. Patients undergoing major lower extremity orthopedic surgery, especially total joint arthroplasty (TJA), are at high risk for developing a postoperative DVT or a subsequent pulmonary embolus. Venous thromboembolic (VTE) prophylaxis, most commonly pharmacologic prophylaxis, has become the standard of care for patients undergoing elective TJA. However, the controversy between the efficacy of VTE prophylaxis and the increased risk for bleeding in the postoperative period continues to exist. This review addresses the controversy underlying VTE prophylaxis by outlining 2 guidelines and demonstrating the pros and cons of different DVT prophylaxis regimens based on the available evidence-based literature. PMID:20399366

Sheth, Neil P; Lieberman, Jay R; Della Valle, Craig J

2010-04-01

397

Current thoughts on total hip replacement.  

PubMed

Opinion leaders in the field of total hip arthroplasty express antipodal views with bewildering frequency. New trends notwithstanding, Charnley low-friction arthroplasty has a record of outstanding success, and we should attempt to identify specific problems, and address these accordingly. Biological and biomechanical matching remain important and increased attention to meticulous cement technique should favourably improve the long-term performance of cemented implants. The concept of cementless replacement should not, however, be summarily discarded, particularly for the younger patient. The discovery of existing design limitations should lead to further development based on sound scientific research. In an era of exploding technology, cost-containment must remain a pragmatic reality in the provision of a health-care service to the community. At this stage we would recommend a cementless hip replacement for the very young, hybrid replacement (cemented stem, uncemented cup) for the middle-aged and a fully cemented replacement for the elderly. PMID:8042105

Learmonth, I D; Spirakis, A

1994-02-01

398

Experiences with computer navigated total knee arthroplasty  

PubMed Central

The successful outcome of total knee arthroplasty (TKA) is very much dependent on precise positioning of the components. Inaccuracy may result in complaints as well as in early mechanical failure. Between March 2003 and September 2005, 69 TKA procedures were performed by the computer navigated technique. The postoperative outcome of this cohort was compared with the same number of TKAs done by the traditional technique. The lower limb anatomical axis was determined in all cases pre- and postoperatively by weight-bearing anteroposterior (AP) and lateral full length X-rays. The positions of femoral and tibial components were recorded. Comparing the data in the navigation group on the AP view, 96.6% of femoral and 96.9% of tibial components and on the lateral view in 95.4% of femoral and in 95.4% of tibial components, the overall postoperative axis in 95.4% fell in the range considered in the literature as optimal. In the traditional group on the AP view, 75.7% of femoral and 68.1% of tibial components and on the lateral view 81.8% of femoral and 63.6% of tibial components, the overall postoperative axis in 60.6% fell between the values considered optimal in the literature. It seems to be proven that the computer navigated total knee arthroplasty technique ensures positioning of components significantly more precisely compared with the traditional surgical method. Accuracy of navigation depends on the software used, on the correct detection of anatomical reference points, and on a potentially uneven thickness of the cement layer during final insertion of the components. The computer navigated technique does not substitute professional skill and experience, since it merely transmits information for the surgeon. The decision is in the hands of the doctor during the entire procedure. The real benefits of the computer navigated technique require further research and can be determined only after long-term analyses. PMID:17115156

Sólyom, László; Szendrői, Miklós

2006-01-01

399

Minimally invasive total hip arthroplasty: in opposition.  

PubMed

At the Knee Society Winter Meeting in 2003, Seth Greenwald and I debated about whether there should be new standards (ie, regulations) applied to the release of information to the public on "new developments." I argued for the public's "right to know" prior to the publication of peer-reviewed literature. He argued for regulatory constraint or "proving by peer-reviewed publication" before alerting the public. It is not a contradiction for me to currently argue against the public advertising of minimally invasive (MIS) total hip arthroplasty as not yet being in the best interest of the public. It is hard to remember a concept that has so captured both the public's and the surgical community's fancy as MIS. Patients are "demanding" MIS without knowing why. Surgeons are offering it as the next best, greatest thing without having developed the skill and experience to avoid the surgery's risks. If you put "minimally invasive hip replacement" into the Google search engine (http://www.google.com), you get 5,170 matches. If you put the same words in PubMed (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi), referencing the National Library of Medicine database, you get SEVENTEEN; none is really a peer-reviewed article. Most are 1 page papers in orthopedics from medical education meetings. On the other hand, there are over 6,000 peer-reviewed articles on total hip arthroplasty. Dr. Thomas Sculco, my couterpart in this debate, wrote an insightful editorial in the American Journal of Orthopedic Surgery in which he stated: "Although these procedures have generated incredible interest and enthusiasm, I am concerned that they may be performed to the detriment of our patients." I couldn't agree with him more. Smaller is not necessarily better and, when it is worse, it will be the "smaller" that is held accountable. PMID:15190556

Hungerford, David S

2004-06-01

400

Total Sleep Time Severely Drops during Adolescence  

PubMed Central

Restricted sleep duration among young adults and adolescents has been shown to increase the risk of morbidities such as obesity, diabetes or accidents. However there are few epidemiological studies on normal total sleep time (TST) in representative groups of teen-agers which allow to get normative data. Purpose To explore perceived total sleep time on schooldays (TSTS) and non schooldays (TSTN) and the prevalence of sleep initiating insomnia among a nationally representative sample of teenagers. Methods Data from 9,251 children aged 11 to 15 years-old, 50.7% of which were boys, as part of the cross-national study 2011 HBSC were analyzed. Self-completion questionnaires were administered in classrooms. An estimate of TSTS and TSTN (week-ends and vacations) was calculated based on specifically designed sleep habits report. Sleep deprivation was estimated by a TSTN – TSTS difference >2 hours. Sleep initiating nsomnia was assessed according to International classification of sleep disorders (ICSD 2). Children who reported sleeping 7 hours or less per night were considered as short sleepers. Results A serious drop of TST was observed between 11 yo and 15 yo, both during the schooldays (9 hours 26 minutes vs. 7 h 55 min.; p<0.001) and at a lesser extent during week-ends (10 h 17 min. vs. 9 h 44 min.; p<0.001). Sleep deprivation concerned 16.0% of chidren aged of 11 yo vs. 40.5% of those of 15 yo (p<0.001). Too short sleep was reported by 2.6% of the 11 yo vs. 24.6% of the 15 yo (p<0.001). Conclusion Despite the obvious need for sleep in adolescence, TST drastically decreases with age among children from 11 to 15 yo which creates significant sleep debt increasing with age. PMID:23082111

Leger, Damien; Beck, Francois; Richard, Jean-Baptiste; Godeau, Emmanuelle

2012-01-01

401

Polyethylene wear in total hip arthroplasty.  

PubMed

Polyethylene wear increasingly has been blamed for osteolysis and granuloma formation after total joint arthroplasty. The authors evaluated the wear difference between bearing surfaces of stainless steel, cobalt chrome, and titanium alloy. They also compared cemented all-polyethylene molded cups with cemented metal-backed molded acetabular cups. These were compared with molded and machined polyethylene cups. Two patient groups were matched individually for gender, age, weight, and length of followup. Analyses were done using the technique of Livermore et al. The bearing surface evaluation consisted of 3 groups after matching, leaving 77 patients per group. Results showed linear wear rates of 0.06 mm per year, 0.05 mm per year, and 0.08 mm per year for stainless steel, cobalt chrome, and titanium alloy, respectively. The comparison between cemented molded metal-backed and nonmetal-backed acetabular components was not matched, with 134 metal-backed and 99 nonmetal-backed components. Results showed linear wear rates of 0.011 mm per year in the metal-backed group and 0.08 mm per year in the nonmetal-backed group. Results were statistically significant. These results indicate that the metal composition of the femoral bearing surface has minimal, if any, effect on the linear polyethylene wear rate. The method of polyethylene fabrication and the use of metal backing had a significant effect on the polyethylene wear rate in these patient groups. These results suggest that the compression-molded all-polyethylene acetabular component may be optimal for reducing polyethylene wear in total hip arthroplasty. PMID:7671498

Bankston, A B; Cates, H; Ritter, M A; Keating, E M; Faris, P M

1995-08-01

402

Image-guided total marrow and total lymphatic irradiation using helical tomotherapy  

SciTech Connect

Purpose: To develop a treatment technique to spare normal tissue and allow dose escalation in total body irradiation (TBI). We have developed intensity-modulated radiotherapy techniques for the total marrow irradiation (TMI), total lymphatic irradiation, or total bone marrow plus lymphatic irradiation using helical tomotherapy. Methods and Materials: For TBI, we typically use 12 Gy in 10 fractions delivered at an extended source-to-surface distance (SSD). Using helical tomotherapy, it is possible to deliver equally effective doses to the bone marrow and lymphatics while sparing normal organs to a significant degree. In the TMI patients, whole body skeletal bone, including the ribs and sternum, comprise the treatment target. In the total lymphatic irradiation, the target is expanded to include the spleen and major lymph node areas. Sanctuary sites for disease (brain and testes) are included when clinically indicated. Spared organs include the lungs, esophagus, parotid glands, eyes, oral cavity, liver, kidneys, stomach, small and large intestine, bladder, and ovaries. Results: With TBI, all normal organs received the TBI dose; with TMI, total lymphatic irradiation, and total bone marrow plus lymphatic irradiation, the visceral organs are spared. For the first 6 patients treated with TMI, the median dose to organs at risk averaged 51% lower than would be achieved with TBI. By putting greater weight on the avoidance of specific organs, greater sparing was possible. Conclusion: Sparing of normal tissues and dose escalation is possible using helical tomotherapy. Late effects such as radiation pneumonitis, veno-occlusive disease, cataracts, neurocognitive effects, and the development of second tumors should be diminished in severity and frequency according to the dose reduction realized for the organs at risk.

Schultheiss, Timothy E. [Department of Radiation Oncology, City of Hope Cancer Center, Duarte, CA (United States)]. E-mail: Schultheiss@coh.org; Wong, Jeffrey [Department of Radiation Oncology, City of Hope Cancer Center, Duarte, CA (United States); Liu, An [Department of Radiation Oncology, City of Hope Cancer Center, Duarte, CA (United States); Olivera, Gustavo [Tomotherapy, Inc., Madison, WI (United States); Somlo, George [Department of Medical Oncology, City of Hope Cancer Center, Duarte, CA (United States)

2007-03-15

403

Total and inorganic arsenic in foods of the first Hong Kong total diet study.  

PubMed

Arsenic (As) is a metalloid that occurs in different inorganic and organic forms, which are found in the environment from both natural occurrence and anthropogenic activity. The inorganic forms of As (iAs) are more toxic as compared with the organic As, but so far most of the occurrence data in food collected in the framework of official food control are still reported as total As without differentiating the various As species. In this paper, total As and iAs contents of 600 total diet study (TDS) samples, subdivided into 15 different food groups, were quantified by high-resolution inductively coupled plasma mass spectrometry (HR-ICP/MS) and hydride generation (HG) ICP/MS respectively. The method detection limits for both total As and iAs were 3 ?g As kg(-1). As the samples were prepared for TDS, food items were purchased directly from the market or prepared as for normal consumption, i.e. table ready, in the manner most representative of and consistent with cultural habits in Hong Kong as far as practicable. The highest total As and iAs content were found in 'fish, seafood and their products' and 'vegetables and their products' respectively. Besides, this paper also presents the ratios of iAs and total As content in different ready-to-eat food items. The highest ratio of iAs to total As was found in 'vegetables and their products'. It is likely that iAs in vegetables maintained its status even after cooking. PMID:24350756

Chung, Stephen Wai-cheung; Lam, Chi-ho; Chan, Benny Tsz-pun

2014-04-01

404

10 CFR 603.520 - Reasonableness of total project funding.  

... false Reasonableness of total project funding. 603.520 Section 603.520 Energy... Pre-Award Business Evaluation Total Funding § 603.520 Reasonableness of total project funding. In cooperation with the...

2014-01-01

405

10 CFR 603.520 - Reasonableness of total project funding.  

Code of Federal Regulations, 2010 CFR

... false Reasonableness of total project funding. 603.520 Section 603.520 Energy... Pre-Award Business Evaluation Total Funding § 603.520 Reasonableness of total project funding. In cooperation with the...

2010-01-01

406

21 CFR 862.1470 - Lipid (total) test system.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Lipid (total) test system. 862.1470 Section...Clinical Chemistry Test Systems § 862.1470 Lipid (total) test system. (a) Identification. A lipid (total) test system is a device...

2013-04-01

407

21 CFR 862.1175 - Cholesterol (total) test system.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Cholesterol (total) test system. 862.1175...Chemistry Test Systems § 862.1175 Cholesterol (total) test system. (a) Identification. A cholesterol (total) test system is a device...

2012-04-01

408

21 CFR 862.1175 - Cholesterol (total) test system.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Cholesterol (total) test system. 862.1175...Chemistry Test Systems § 862.1175 Cholesterol (total) test system. (a) Identification. A cholesterol (total) test system is a device...

2011-04-01

409

21 CFR 862.1175 - Cholesterol (total) test system.  

...2014-04-01 2014-04-01 false Cholesterol (total) test system. 862.1175...Chemistry Test Systems § 862.1175 Cholesterol (total) test system. (a) Identification. A cholesterol (total) test system is a device...

2014-04-01

410

Original article Serum total cholesterol, high-density lipoprotein-  

E-print Network

Original article Serum total cholesterol, high-density lipoprotein- cholesterol and triglyceride- copherol provided daily in equimolar amounts on total cholesterol, high-density lipoprotein- cholesterol sources resulted in no overall treatment effects for total cholesterol, triglycerides or high density

Paris-Sud XI, Université de

411

21 CFR 862.1175 - Cholesterol (total) test system.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Cholesterol (total) test system. 862.1175...Chemistry Test Systems § 862.1175 Cholesterol (total) test system. (a) Identification. A cholesterol (total) test system is a device...

2010-04-01

412

21 CFR 862.1175 - Cholesterol (total) test system.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Cholesterol (total) test system. 862.1175...Chemistry Test Systems § 862.1175 Cholesterol (total) test system. (a) Identification. A cholesterol (total) test system is a device...

2013-04-01

413

21 CFR 872.3940 - Total temporomandibular joint prosthesis.  

Code of Federal Regulations, 2010 CFR

...false Total temporomandibular joint prosthesis. 872.3940 Section 872.3940...3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is intended...

2010-04-01

414

Zooplankton and the total phosphorus chlorophyll a relationship: hierarchical Bayesian  

E-print Network

Zooplankton and the total phosphorus ­ chlorophyll a relationship: hierarchical Bayesian analysis: Zooplankton grazing is important in resolving residual variation around the total phosphorus ­ chlorophyll found consistent effects of total zooplankton biomass, but not zooplankton length, on chlorophyll a

Notre Dame, University of

415

Apparatus and method for quantitatively evaluating total fissile and total fertile nuclide content in samples  

DOEpatents

Simultaneous photon and neutron interrogation of samples for the quantitative determination of total fissile nuclide and total fertile nuclide material present is made possible by the use of an electron accelerator. Prompt and delayed neutrons produced from resulting induced fissions are counted using a single detection system and allow the resolution of the contributions from each interrogating flux leading in turn to the quantitative determination sought. Detection limits for .sup.239 Pu are estimated to be about 3 mg using prompt fission neutrons and about 6 mg using delayed neutrons.

Caldwell, John T. (Los Alamos, NM); Kunz, Walter E. (Santa Fe, NM); Cates, Michael R. (Oak Ridge, TN); Franks, Larry A. (Santa Barbara, CA)

1985-01-01

416

[Hirschsprung disease. (Except total forms) (author's transl)].  

PubMed

This panel discussion was considered for paediatricians attending a specialisation conference. The study eliminates total colonictypes. The first part is devoted to clinical study of symptoms in neonates and enterocolitis. Two different types are advocated, due to different aetiologies : The first to obstruction. The second one to Schwartzman reaction similar as Necrotizing enterocolitis of the premature baby. The second part analyzes the methods of diagnosis. No discussion about pathology and X. Ray. Pellerin trust mainly pressure studies, while Carcassonne never operates on a cases without a biopsy, even if the manometry, is positive. About biopsy he used for 4 years now, the Helen Noblett device with great confidence. Polonovski discusses the differential diagnosis with so called pseudo and false Hirschprung. The third part gives the different trends of the authors in matter of treatment: --Pellerin studies the indications for nursing, while Jaubert analyses his series of Colostomies. -- The curative procedures are shortly discussed : Pellerin using the Swenson-Pellerin procedure, Jauber spliting himself between Senson and Soave, Carcassone using Swenson. Two series of immediate and late results are assessed that prove an improvement of the results with the experience of the surgeons. PMID:729134

1978-01-01

417

Aminophylline Compatibility with Neonatal Total Parenteral Nutrition  

PubMed Central

OBJECTIVES Aminophylline has proven useful for treating renal failure in preterm infants. Previous reports state that aminophylline is incompatible with some neonatal total parenteral nutrition (TPN) solutions. If this is correct, administration of aminophylline doses would be complicated by the need to hold TPN and provide flush solution after each aminophylline dose. Our experience with administering aminophylline over 30 minutes concurrently with TPN was that this was not problematic. We therefore examined the in vitro compatibility of aminophylline and TPN solutions used in our neonates over a 30-minute interval to see if our policy of allowing concurrent mixing of these products was appropriate. METHODS TPN solutions (2.5 mL) were mixed with 1 mL of intravenous aminophylline 2.5 mg/mL in a glass vial. Three different TPN solutions used in our NICU were collected for the study, and five samples of each combination were prepared. Samples were watched for 60 minutes to see if precipitation occurred. RESULTS Although the aminophylline and TPN solutions were not miscible, no turbidity or precipitation was observed. CONCLUSIONS This study supports that aminophylline is physically compatible with neonatal TPN for 60 minutes. PMID:23055868

Sykes, Rachel; McPherson, Christopher; Foulks, Kristi; Wade, Joni; Gal, Peter

2008-01-01

418

Friction couples in total hip replacement.  

PubMed

The problem of friction couples remains unresolved to this day. Improvements in femoral and acetabulum implant anchorage over the last 20 years have significantly extended total hip replacement (THR) implant lifespan; the formation of wear debris, however, leads to resorption and osteolysis, considerably shortening implant lifespan in active patients. Alumina-alumina friction couples provide an excellent friction coefficient, with wear particles that do not cause any osteolysis. There is, however, a problem of acetabulum anchorage of solid alumina, and the risk of fracture persists with ceramic implants despite improvements in their mechanical properties. Metal-metal couples also display very good tribological behavior, but at the cost of the formation of Co and Cr ions impacting surrounding bone tissue and accumulating in remote organs. The behavior of such "hard-hard" couples greatly depends on implant component positioning and on the consequences of repeated neck-insert contact. Very highly crosslinked polyethylene (PE) shows very significant improvement in terms of wear at five years' follow-up compared to conventional PE, but the behavior of this new concept will need to be monitored in the clinical situation if the disappointments experienced with previous hylamer-type improved PE are to be avoided. All these friction couples need to be validated by prospective clinical studies conducted over more than five years, to provide orthopedic surgeons with an eclectic choice of friction couples adapted to the patient's activity. PMID:19442600

Passuti, N; Philippeau, Jm; Gouin, F

2009-06-01

419

Total internal reflection photoacoustic detection spectroscopy  

NASA Astrophysics Data System (ADS)

Total Internal Reflection Photoacoustic Spectroscopy (TIRPAS) is a method that exploits the evanescent field of a nanosecond duration laser pulse reflecting off a glass/water interface to generate photoacoustic responses. These photoacoustic events are generated in light absorbing analytes suspended in the fluid medium in contact with the glass that are within the penetration depth of the evanescent wave. This method has been employed in previous studies by Hinoue et al. Hinoue et al. used an optically chopped HeNe laser at 632.8 nm to detect Brilliant Blue FCF dye at different angles of incidence. In recent years, the advent of high power nanosecond pulsed tunable lasers has allowed for the re-visitation of the TIRPAS idea under stress confinement and orders of magnitude larger peak energy conditions. Compared to conventional detection methods, this approach has the potential to detect much smaller quantities of disease indicators, such as circulating tumor cells and hemazoin crystals in malaria, than other optical methods. The detection limit of the TIRPAS system was quantified using chlorazol black solution with an absorption coefficient of 55 cm-1 at 532 nm. Interaction with the evanescent field was verified by varying the angle of incidence of the probe laser beam that generated the photoacoustic waves, thereby changing the penetration depth of the evanescent field as well as the photoacoustic spectroscopy effect from angled excitation.

Sudduth, Amanda S. M.; Goldschmidt, Benjamin S.; Samson, Edward B.; Whiteside, Paul J. D.; Viator, John A.

2011-03-01

420

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

421

Total Electron Content forecast model over Australia  

NASA Astrophysics Data System (ADS)

Ionospheric perturbations can cause serious propagation errors in modern radio systems such as Global Navigation Satellite Systems (GNSS). Forecasting ionospheric parameters is helpful to estimate potential degradation of the performance of these systems. Our purpose is to establish an Australian Regional Total Electron Content (TEC) forecast model at IPS. In this work we present an approach based on the combined use of the Principal Component Analysis (PCA) and Artificial Neural Network (ANN) to predict future TEC values. PCA is used to reduce the dimensionality of the original TEC data by mapping it into its eigen-space. In this process the top- 5 eigenvectors are chosen to reflect the directions of the maximum variability. An ANN approach was then used for the multicomponent prediction. We outline the design of the ANN model with its parameters. A number of activation functions along with different spectral ranges and different numbers of Principal Components (PCs) were tested to find the PCA-ANN models reaching the best results. Keywords: GNSS, Space Weather, Regional, Forecast, PCA, ANN.

Bouya, Zahra; Terkildsen, Michael; Francis, Matthew

422

[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

423

[Total quality management in laboratory medicine].  

PubMed

The German Public Health will be continuously challenged in the future. It has to be assumed that modified managed care will not only take place sporadically. Thus, quality aspects of services gain more and more significance. Only suppliers will be successful who can offer services of highest quality at lowest prices. Quality in a comprehensive sense has to be substantiated in the near future. It is recommended to apply industry proven models also in public health service. Medical laboratories can be pioneers in this field as they have been already in the past. All previously proposed procedures can not describe quality of results comprehensively. They are based to a high degree on external control. Total quality management, however, represents a comprehensive approach. Principles are zero-defect approach, customer orientation and system management. Quality is given in the sense of TQM if the customer is permanently satisfied with the service of the supplier. In such a way, the customer defines quality of service. A customer is everyone who receives products or services. TQM overcomes the drawbacks of quality management systems, which are strongly formal and oriented by external control, as accreditation (EN 45,000) or certification (ISO 9000). Competition between hospitals is a declared goal of German health politics because usually quality is increased and cost decreased as a consequence. Competition means also comparison of services. TQM emphasizes benchmarking especially among the best suppliers. PMID:10028601

Vogt, W

1998-12-01

424

Quantitative surface analysis by total electron yield.  

PubMed

When the surface of a solid sample is irradiated under vacuum by x-rays an electron emission, owing to photoabsorption, can be measured. As the electrons are detected under neglection of their kinetic energies the total electron yield (TEY) is determined. With a tuneable x-ray monochromator the TEY is measured below and above of one of the absorption edges of a given element. A jumplike increase of the TEY signal, due to the additional photoabsorptions in the corresponding atomic level, can be observed - qualitative analysis. The height of this jump can be correlateted to the concentration - quantitative analysis. It can be shown by a fundamental parameter approach for primary and secondary excitations how to use TEY for a quantitative analysis. The information depth lambda of this new method is approximately 2-400 nm depending on the chemical elements and on the original kinetic energies of Auger and photoelectrons. Thus, TEY is located between photoelectron spectrometry and x-ray fluorescence analysis. PMID:15048496

Ebel, H; Zagler, N; Svagera, R; Ebel, M; Kaitna, R

1995-10-01

425

Patellar options in revision total knee arthroplasty.  

PubMed

There are numerous options that need to be considered by the surgeon at the time of revision total knee arthroplasty (TKA). One needs to consider the reason for the revision, the type of patella in place, and the length of time the patella has been in place. The surgeon also needs to consider the status of the patellar bone stock, the stability of the patellar component (well-fixed or loose), and the component type (cemented or metal-backed). Assuming that the existing prosthesis is not metal-backed and has minimal PE wear, then it is preferable to retain a well-fixed all-PE cemented patellar button. However, if the button is metal-backed, then it probably is best to remove the button and replace it with an all-PE domed patellar component. Assuming more than 8 mm of patellar bone stock is remaining, it usually is best to cement an all-PE dome-shaped patella. However, if less than 8 mm is remaining, then that patient can be left with a patelloplasty, recognizing that this individual is going to continue with a high likelihood of anterior knee pain, subluxation, and poor functional results. In that situation, it may be preferable to consider a bone stock augmentation. PMID:14646744

Rorabeck, Cecil H; Mehin, Ramin; Barrack, Robert L

2003-11-01

426

Radiobiological speculations on therapeutic total body irradiation  

SciTech Connect

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 a lethal bone marrow disorder for bone marrow replacement. The therapeutic ratio of TBI followed by bone marrow transplantation is small. Many potentially lethal complications can occur, such as acute TBI side effects, late TBI side effects or immunological complications of bone marrow transplantation such as graft versus host disease or graft rejection. The benefits of TBI and bone marrow transplantation are that they offer a chance for cure of previously lethal bone marrow disorders. The optimal parameters for TBI remain to be defined. The review discusses the current clinical and experimental animal data, as they relate to the future definition of less toxic TBI procedures with a better therapeutic ratio. Different TBI procedures are required for patients with malignant vs. non-malignant disorders or for patients with histoincompatible vs. histocompatible bone marrow donors.77 references.

Vriesendorp, H.M. (Johns Hopkins Hospital, Baltimore, MD (USA))

1990-01-01

427

Single tag for total carbohydrate analysis.  

PubMed

Anthranilic acid (2-aminobenzoic acid, 2-AA) has the remarkable property of reacting rapidly with every type of reducing carbohydrate. Reactivity of 2-AA with carbohydrates in aqueous solutions surpasses all other tags reported to date. This unique capability is attributed to the strategically located -COOH which accelerates Schiff base formation. Monosaccharides, oligosaccharides (N-, O-, and lipid linked and glycans in secretory fluids), glycosaminoglycans, and polysaccharides can be easily labeled with 2-AA. With 2-AA, labeling is simple in aqueous solutions containing proteins, peptides, buffer salts, and other ingredients (e.g., PNGase F, glycosidase, and transferase reaction mixtures). In contrast, other tags require relatively pure glycans for labeling in anhydrous dimethyl sulfoxide-acetic acid medium. Acidic conditions are known to cause desialylation, thus requiring a great deal of attention to sample preparation. Simpler labeling is achieved with 2-AA within 30-60 min in mild acetate-borate buffered solution. 2-AA provides the highest sensitivity and resolution in chromatographic methods for carbohydrate analysis in a simple manner. Additionally, 2-AA is uniquely qualified for quantitative analysis by mass spectrometry in the negative mode. Analyses of 2-AA-labeled carbohydrates by electrophoresis and other techniques have been reported. Examples cited here demonstrate that 2-AA is the universal tag for total carbohydrate analysis. PMID:24769375

Anumula, Kalyan Rao

2014-07-15

428

Total Synthesis of (-)-Pseudolaric Acid B  

PubMed Central

We report a full account of our work towards the total synthesis of pseudolaric acid B (1a), a diterpene acid isolated from the bark of Pseudolarix kaempferi Gordon (pinaceae). Pseudolaric Acid B (1a) is an antifungal and antifertility agent. Furthermore, its capacity of inhibiting tubulin polymerization makes it a lead compound for cancer therapy. Herein, we describe the use of a Ru or Rh catalyzed [5+2] intramolecular cycloaddition reaction of an alkyne and a vinylcyclopropane for the construction of the polyhydroazulene core of the molecule. Our first unsuccessful strategy towards the introduction of the quaternary center based on an epoxide opening with cyanide led to the discovery of a new TBAF mediated isomerization of 1,4 diene to 1,3 diene and a vinylogous eliminative opening of an epoxide to form a dienol. Our second strategy, based on the cyclization of an alkoxycarbonyl radical upon a diene system, succeeded in forming the quaternary center. Detailed studies showed the dependence of this underutilized approach for the synthesis of lactones from substrate structure and reaction conditions. In the late stage of the synthesis, the unique capacity of cerium organometallic reagents to add onto sensitive sterically hindered ketone was demonstrated. The easy formation of an oxo-bridged derivative was the major hurdle for the completion of the synthesis and showcased the intriguing reactivity of the complex core of the pseudolaric acids. PMID:18998641

Trost, Barry M.; Waser, Jerome; Meyer, Arndt

2009-01-01

429

Total lightning activity in thunderstorms over Paris  

NASA Astrophysics Data System (ADS)

A statistical study of two groups of storms that occurred in the Paris area (France) during summer 2000 has been realized. The first group includes 26 high radar reflectivity (HRR) storms with radar reflectivity values exceeding 60 dBZ while the second one includes 19 moderate radar reflectivity (MRR) storms with a maximum radar reflectivity value between 50 and 55 dBZ. The radar reflectivity was provided by a C-band radar and the total lightning activity (cloud-to-ground (CG) and intra-cloud (IC) flashes) was provided by the French Météorage network and a Safir device. HRR storms seem to be characterized by a longer lifetime, and a more extended convective area. On average, they produce more CG and IC flashes than MRR storms. However, a large variability in the number, the rate, and the type of flashes is observed. The HRR storms producing the highest IC flash rates (above 100 min - 1 ) exhibit the lowest CG flash proportion (1.2 and 4.3%). Most of the HRR storms exhibit a peak lightning activity when the radar reflectivity is strong at low level within the cloud. However, several cases of these storms show a large time lag between the strong lightning production and the presence of high radar reflectivity values at low level. Some possible explanations of these observations, taking into account cloud dynamics, microphysics and lightning initiation, are discussed.

Boussaton, M. P.; Soula, S.; Coquillat, S.

2007-05-01

430

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

431

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

432

Quantitative analysis of total flavonoids and total phenolic acids in thirty Hypericum taxa.  

PubMed

The content of total flavonoids and total phenolic acids in the aerial parts of thirty Hypericum taxa collected over two consecutive seasons was investigated by spectrophotometric methods. All taxa examined contained flavonoids and phenolic acids in different quantities, although the differences between species and year's harvest were not found to be significant. The quantity of total flavonoids ranged from 0.1 to 1.6%. The highest content of flavonoids was found in the samples of H. japonicum (1.6%) and H. perforatum (1.5%), while the samples of H. androsaemum and H. balearicum comprised the lowest flavonoid amount (0.13%). The content of total phenolic acids in the investigated samples was found to be between 1.1-10.4%. The samples of H. perforatum were found to contain the highest quantity of phenolic acids (10.4% and 10.2%), whereas the sample ofH. linarifolium showed the lowest amount of phenolic acids (1.1%). PMID:23678809

Pilepi?, Kroata Hazler; Males, Zeljan; Crkvenci?, Maja

2013-03-01

433

Sources of Solar Total Irradiance Variations  

NASA Astrophysics Data System (ADS)

The daily images and magnetograms acquired by MDI are a rich source of information about the contributions of different types of solar regions to variations in the total solar irradiance (TSI). These data have been used to determine the temporal variation of the MDI irradiance, the mean intensity of the solar disk in the continuum at 676.8 nm. The short-term (days to weeks) variations of the MDI irradiance and TSI are in excellent agreement with rms differences of 0.011%. This indicates that MDI irradiance is an excellent proxy for short-term variations of TSI from the competing irradiance contributions of regions causing irradiance increases, such as plages and bright network, and regions causing irradiance decreases, such as sunspots. However, the long-term or solar cycle variation of the MDI proxy and TSI differ over the 11-year period studied. The results indicate that the primary sources of the long-term (several months or more) variations in TSI are regions with magnetic fields between about 80 and 600 G. The results also suggest that the difference in the long-term variations of the MDI proxy and TSI is due to a component of TSI associated with sectors of the solar spectrum where the contrast in intensity between plages and the quiet Sun is enhanced ( e.g., the UV) compared to the MDI proxy. This is evidence that the long-term variation of TSI is due primarily to solar cycle variations of the irradiance from these portions of solar spectrum, a finding consistent with modeling calculations indicating that approximately 60% of the change in TSI between solar minimum and maximum is produced by the UV part of the spectrum shortward of 400 nm (Solanki and Krivova, Space Sci. Rev. 125, 53, 2006).

Withbroe, George L.

2009-06-01

434

Aperture modulated, translating bed total body irradiation  

SciTech Connect

Purpose: Total body irradiation (TBI) techniques aim to deliver a uniform radiation dose to a patient with an irregular body contour and a heterogeneous density distribution to within {+-}10% of the prescribed dose. In the current article, the authors present a novel, aperture modulated, translating bed TBI (AMTBI) technique that produces a high degree of dose uniformity throughout the entire patient. Methods: The radiation beam is dynamically shaped in two dimensions using a multileaf collimator (MLC). The irregular surface compensation algorithm in the Eclipse treatment planning system is used for fluence optimization, which is performed based on penetration depth and internal inhomogeneities. Two optimal fluence maps (AP and PA) are generated and beam apertures are created to deliver these optimal fluences. During treatment, the patient/phantom is translated on a motorized bed close to the floor (source to bed distance: 204.5 cm) under a stationary radiation beam with 0 deg. gantry angle. The bed motion and dynamic beam apertures are synchronized. Results: The AMTBI technique produces a more homogeneous dose distribution than fixed open beam translating bed TBI. In phantom studies, the dose deviation along the midline is reduced from 10% to less than 5% of the prescribed dose in the longitudinal direction. Dose to the lung is reduced by more than 15% compared to the unshielded fixed open beam technique. At the lateral body edges, the dose received from the open beam technique was 20% higher than that prescribed at umbilicus midplane. With AMTBI the dose deviation in this same region is reduced to less than 3% of the prescribed dose. Validation of the technique was performed using thermoluminescent dosimeters in a Rando phantom. Agreement between calculation and measurement was better than 3% in all cases. Conclusions: A novel, translating bed, aperture modulated TBI technique that employs dynamically shaped MLC defined beams is shown to improve dose uniformity in three dimensions. In comparison with the fixed open beam TBI technique, homogeneity of dose distribution is greatly improved.

Hussain, Amjad; Villarreal-Barajas, Jose Eduardo; Dunscombe, Peter; Brown, Derek W. [Department of Medical Physics, Tom Baker Cancer Centre, Calgary, Alberta T2N 4N2 (Canada); Department of Medical Physics, Tom Baker Cancer Centre, Calgary, Alberta T2N 4N2 (Canada) and Department of Oncology, University of Calgary, Calgary, Alberta T2N 4N2 (Canada)

2011-02-15

435

Total Hip Arthroplasty for Hip Fractures  

PubMed Central

Introduction: This study aimed to determine the dislocation and reoperation rate, functional outcomes, and the survival rate of the unique subset of very old but lucid and independent patients with hip fractures following a total hip arthroplasty (THA) and geriatric team-coordinated perioperative care. Method: Between 2000 and 2006, previously independent ambulatory patients ?80 years old presenting with an intracapsular hip fracture were given THAs under the care of an integrated orthopedic surgery–geriatric service. Their fracture-related complications, ambulation, mental status, and survival were followed for 5 to 11 years postinjury. Results: Five years postinjury, 57 (61.3%) patients of the original study group were living. In all, 3 (3.2%) patients had postoperative hip dislocations (and 2 patients had dislocation twice) and 2 reoperations were needed within the first postoperative month. There were no hip dislocations or reoperations after the first year. Radiographs obtained on 88% of the surviving patients at 5 years postoperatively showed that all remained unchanged from their immediate postoperative images. Nearly half of the patients were still able to ambulate as they did preoperatively and their mixed-model equation was statistically unchanged. Conclusion: This study of patients >80 years old with previously good functional status demonstrates that with appropriate surgical (best prosthesis, good operating technique, and regional anesthesia) and geriatric (pre- and postoperative assessments, close follow-up, medication adjustments, and fall-prevention instruction) care, they have few hip dislocations and reoperations, survive postfracture at least as long as their noninjured contemporaries, and continue to function and ambulate as they did prior to their injury. PMID:24660092

Monzon, Daniel Godoy; Iserson, Kenneth V.; Jauregui, Jose; Musso, Carlos; Piccaluga, Francisco; Buttaro, Martin

2014-01-01

436

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

437

Early biomarkers of hypocalcemia following total thyroidectomy.  

PubMed

Hypocalcemia is the most frequent major complication following total thyroidectomy (TT), delaying timely hospital demission. We prospectively evaluated the diagnostic utility of parathyroid hormone (PTH) measured one hour after TT and the delta (post-minus pre-surgery) PTH in order to determine which biomarker best predicted post-surgery hypocalcemia. Ninety-six consecutive patients, with either plurinodular goiter, Graves' disease or cervico-mediastinal goiter (22 (23%) men and 74 (77%) women, mean age 48.5 ± 15.2 and 47.9 ± 13.2 years, respectively), scheduled to undergo TT were enrolled. PTH was measured prior and one hour after surgery. Delta PTH was defined as one-hour post-surgery values minus pre-surgery PTH level. Hypocalcemia was defined as a calcemia under 8.0 mg/dL. Receiver operating characteristic (ROC) analysis was used to evaluate the Area Under Curve (AUC), sensibility and specificity of the two biomarkers for the occurrence of hypocalcemia. Forty-nine (51%) patients presented biochemical values under the cut-off but only 17 (18%) had clinical symptoms. Both variables yielded statistically significant AUC (PTH one-hour post surgery: 0.654; p = 0.0403; 95%CI: 0.519-0.773 and delta PTH: 0.659; p = 0.0263; 95%CI: 0.527-0.776). Although comparison of the two ROC curves did not yield significant differences, delta PTH yielded a better sensitivity and PTH one-hour post-TT yielded a marginally better specificity (sensitivity of 50% and 87% and specificity of 76% and 67% for cut-offs of <39.8 pg/dl and <54.5 pg/dl, respectively). Both biomarkers have similar diagnostic accuracy for hypocalcemia, and can be used to indicate when supplemental therapy should be implemented in order to favor a timely discharge. PMID:24862663

Bove, A; Di Renzo, R M; Palone, G; D'Addetta, V; Percario, R; Panaccio, P; Bongarzoni, G

2014-01-01

438

Infection after primary total hip arthroplasty.  

PubMed

The number of primary total hip arthroplasties (THAs) performed in the United States each year continues to climb, as does the incidence of infectious complications. The changing profile of antibiotic-resistant bacteria has made preventing and treating primary THA infections increasingly complex. The goal of this review was to summarize (1) the published data concerning the risk of surgical site infection (SSI) after primary THA by type of bacteria and (2) the effect of potentially modifying factors. The Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, EMBASE, Web of Science, and PubMed were searched. Studies dated between 2001 and 2011 examining primary THA in adults were included. Meta-analysis of the collected data was performed. The pooled SSI rate was 2.5% (95% confidence interval [Cl], 1.4%-4.4%; P<.001; n=28,883). The pooled deep prosthetic joint infection (PJI) rate was 0.9% (95% Cl, 0.4%-2.2%; P<.001; n=28,883). The pooled rate of methicillin-resistant Staphylococcus aureus SSI was 0.5% (95% Cl, 0.2%-1.5%; P<.001; n=26,703). This is approximately 20% of all SSI cases. The pooled rate of intraoperative bacterial wound contamination was 16.9% (95% Cl, 6.6%-36.8%; P=.003; n=2180). All these results had significant heterogeneity. The postoperative risk of SSI was significantly associated with intraoperative bacterial surgical wound contamination (pooled rate ratio, 2.5; 95% Cl, 1.4%-4.6%; P=.001; n=19,049). PMID:24762833

Lindeque, Bennie; Hartman, Zach; Noshchenko, Andriy; Cruse, Margaret

2014-04-01

439

10-year survival of total ankle arthroplasties  

PubMed Central

Background and purpose There is an ongoing need to review large series of total ankle replacements (TARs) for monitoring of changes in practice and their outcome. 4 national registries, including the Swedish Ankle Register, have previously reported their 5-year results. We now present an extended series with a longer follow-up, and with a 10-year survival analysis. Patients and methods Records of uncemented 3-component TARs were retrospectively reviewed, determining risk factors such as age, sex, and diagnosis. Prosthetic survival rates were calculated with exchange or removal of components as endpoint—excluding incidental exchange of the polyethylene meniscus. Results Of the 780 prostheses implanted since 1993, 168 (22%) had been revised by June 15, 2010. The overall survival rate fell from 0.81 (95% CI: 0.79–0.83) at 5 years to 0.69 (95% CI: 0.67–0.71) at 10 years. The survival rate was higher, although not statistically significantly so, during the latter part of the period investigated. Excluding the STAR prosthesis, the survival rate for all the remaining designs was 0.78 at 10 years. Women below the age of 60 with osteoarthritis were at a higher risk of revision, but age did not influence the outcome in men or women with rheumatoid arthritis. Revisions due to technical mistakes at the index surgery and instability were undertaken earlier than revisions for other reasons. Interpretation The results have slowly improved during the 18-year period investigated. However, we do not believe that the survival rates of ankle replacements in the near future will approach those of hip and knee replacements—even though improved instrumentation and design of the prostheses, together with better patient selection, will presumably give better results. PMID:22066551

2011-01-01

440

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

441

Soil Test P vs. Total P in Wisconsin Soils  

E-print Network

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

Balser, Teri C.

442

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

443

Total Phenolic, Total Flavonoids, Antioxidant and Antimicrobial Activities of Scrophularia Striata Boiss Extracts  

PubMed Central

Background Scrophularia striata (Scrophulariaceae family) is an herbaceous plant that is traditionally used for treatment of microbial infections. Objectives Antimicrobial and antioxidant activity of different extracts (methanolic, ethanolic, aqueous and ethyl acetate) from S. striata aerial parts was evaluated. Materials and Methods The antimicrobial activity of different extracts from S. striata was evaluated against a large number of bacteria and fungi by micro broth dilution. Total phenolic and flavonoid contents were measured and their antioxidant activities evaluated by DPPH assay and beta carotene linoleic acid test. Results Antimicrobial screening exhibited the positive relation between the total phenolic content and its antimicrobial activity but their antioxidant activity had a negative relation. Conclusions Further studies are recommended against clinical isolate of sensitive bacteria and deep investigation on flavonoid and phenolic compounds of S. striata and detecting the antioxidant portion in aqueous extract. PMID:24624181

Mahboubi, Mohaddese; Kazempour, Nastaran; Boland Nazar, Ali Reza

2013-01-01

444

Total Laparoscopic Hysterectomy Versus Total Abdominal Hysterectomy: Cohort Review of Patients With Uterine Neoplasia  

PubMed Central

Objective: Retrospective analysis of surgico-pathologic data comparing total laparoscopic hysterectomy (TLH) with total abdominal hysterectomy (TAH) patients with uterine neoplasia Methods: We conducted a chart abstraction of all patients undergoing hysterectomy for uterine neoplasia from September 1996 to November 2004. Patients were assigned to undergo the abdominal or laparoscopic approach based on established clinical safety criteria. Results: The study included 105 patients, 29 with TAH and 76 with TLH. TAH patients were older (68 vs. 61, P=0.021); however, both groups had similar body mass indexes (31) and parities (1.6). Controlling for age, surgical duration was similar (152 minutes). Average blood loss was higher for TAH, (504 vs.138 mL, P<0.001). Hospital stays were significantly longer for patients with TAH than for those with TLH (5.4 vs. 1.8 days, P<0.0001). Uterine weight was greater (197 vs. 135 g, P=0.008) and myometrial invasion deeper in the TAH group (48% outer half vs. 17%, P=0.001). More patients had Stage II or higher disease in the TAH group (35% vs. 17%, P=0.038). More TAH patients needed node dissection (79% vs. 28%, P<.001). Node yields from dissections of 23 TAH cases and 21 laparoscopic cases were similar (17 nodes). Total and reoperative complications from TAH versus TLH were not statistically different in our small sample (14.3 vs. 5.2% total, NS; 10.3 vs. 2.6% reoperative). One conversion was necessary from laparoscopy to laparotomy for unsuspected bulky metastatic disease. Conclusion: Based on clinical selection criteria, TLH performed for endometrial pathology has few complications and is well tolerated by select patients. The advantages are less blood loss and a shorter length of hospital stay for qualified patients. PMID:16121872

Huang, Gloria Shining; Garnier, Anne-Caroline; Dibble, Suzanne L.; Reuland, Mirjam L.; Lopez, Lisbeth; Pinto, Rebecca L.

2005-01-01

445

Primary total hip arthroplasty with a cementless porous-coated anatomic total hip prosthesis  

Microsoft Academic Search

We performed a prospective study in 108 consecutive patients (116 hips) who were followed for a minimum of 10 years (10–12 years) after primary total hip arthroplasty using an uncemented porous-coated anatomic (PCA) hip prosthesis. The average age of the patients at operation was 48.4 years (range, 19–85 years), and the diagnosis was avascular necrosis of the femoral head in

Young-Hoo Kim; Jun-Shik Kim; Soon-Ho Cho

1999-01-01

446

Robotic Assisted, Total Laparoscopic, and Total Abdominal Hysterectomy for Management of Uterine Cancer  

PubMed Central

Objectives The purpose was to compare robotic assisted total laparoscopic hysterectomy (TRH), laparoscopic assisted hysterectomy (TLH) and total abdominal hysterectomy (TAH) with surgical staging +/- lymphadenectomy for the management of uterine cancer. Methods Institutional review board approval was obtained and patient characteristics, pathologic data, and data related to the surgical procedure were collected from chart review. Data were analyzed with SAS statistical software. Results A total of 102 TRHs were compared to 115 TLHs and 79 TAHs. There were more grade I and endometrial intraepithelial (EIN) lesions in the preoperative pathology of TLHs (P < 0.01). Pelvic lymphadenectomy was performed in 71 (70%) TRH, 46 (58%) TAH, and 28 (24%) TLH cases (P < 0.01). Mean surgical time was 203, 133 and 132 minutes for TRHs, TLHs, and TAHs (P < 0.05). Estimated blood loss was 69, 86, and 215 ml for TRH, TLH, and TAH (P < 0.05). Blood transfusions were 19% in TAHs versus 3% and 2% in TLHs and TRHs (P < 0.01). There were fewer wound infections (2% vs. 10%) in TRHs versus TAHs (P < 0.01). Length of stay was shorter for the TRH and TLH groups (P < 0.05). Conclusion Despite longer surgical times, benefits of minimally invasive technology included shortened length of stay, decreased wound infections, transfusions, and blood loss. In our population, procedure selection for TLH versus TRH may have been influenced by lower preoperative grade, with reservation of robotic technology for cases anticipated to be more complex, and therefore justifying increased technology costs and operating times. PMID:24482733

Nicole, Nevadunsky; Rachel, Clark; Michael, Muto; Ross, Berkowitz; Sue, Ghosh; Allison, Vitonis; Colleen, Feltmate

2013-01-01

447

Development of software sensors for determining total phosphorus and total nitrogen in waters.  

PubMed

Total nitrogen (TN) and total phosphorus (TP) concentrations are important parameters to assess the quality of water bodies and are used as criteria to regulate the water quality of the effluent from a wastewater treatment plant (WWTP) in Korea. Therefore, continuous monitoring of TN and TP using in situ instruments is conducted nationwide in Korea. However, most in situ instruments in the market are expensive and require a time-consuming sample pretreatment step, which hinders the widespread use of in situ TN and TP monitoring. In this study, therefore, software sensors based on multiple-regression with a few easily in situ measurable water quality parameters were applied to estimate the TN and TP concentrations in a stream, a lake, combined sewer overflows (CSOs), and WWTP effluent. In general, the developed software sensors predicted TN and TP concentrations of the WWTP effluent and CSOs reasonably well. However, they showed relatively lower predictability for TN and TP concentrations of stream and lake waters, possibly because the water quality of stream and lake waters is more variable than that of WWTP effluent or CSOs. PMID:23307350

Lee, Eunhyoung; Han, Sanghoon; Kim, Hyunook

2013-01-01

448

21 CFR 862.1700 - Total thyroxine test system.  

Code of Federal Regulations, 2012 CFR

...Identification. A total thyroxine test system is a device intended to measure total (free and protein bound) thyroxine (thyroid hormone) in serum and plasma. Measurements obtained by this device are used in the diagnosis and treatment of thyroid...

2012-04-01

449

21 CFR 862.1700 - Total thyroxine test system.  

Code of Federal Regulations, 2013 CFR

...Identification. A total thyroxine test system is a device intended to measure total (free and protein bound) thyroxine (thyroid hormone) in serum and plasma. Measurements obtained by this device are used in the diagnosis and treatment of thyroid...

2013-04-01

450

Joint Line Reconstruction in Navigated Total Knee Arthroplasty Revision  

ClinicalTrials.gov

Revision Total Knee Arthroplasty Because of; Loosening; Instability; Impingement; or Other Reasons Accepted as Indications for TKA Exchange.; The Focus is to Determine the Precision of Joint Line Restoration in Navigated vs. Conventional Revision Total Knee Arthroplasty

2012-05-16

451

20 CFR 404.1903 - Negotiating totalization agreements.  

Code of Federal Regulations, 2010 CFR

...404.1903 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Totalization Agreements General Provisions § 404.1903 Negotiating totalization agreements. An agreement...

2010-04-01

452

Rainfall Totals from the Tropical Cyclones Passing Over Philippines  

NASA Video Gallery

Rainfall totals from the TRMM satellite of all tropical cyclones that passed through the Philippines from January through November 11, 2013. Red indicated areas where rainfall totals were greater t...

453

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

454

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) %

455

Recommended Amounts of Total red and orange vegetables  

Cancer.gov

Recommended Amounts of Total red and orange vegetables Table B4. Total red and orange vegetables: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting

456

Total and ionization cross sections of electron scattering by fluorocarbons  

NASA Astrophysics Data System (ADS)

Electron impact total cross sections (50-2000 eV) and total ionization cross sections (threshold to 2000 eV) are calculated for typical plasma etching molecules CF4, C2F4, C2F6, C3F8 and CF3I and the CFx (x = 1-3) radicals. The total elastic and inelastic cross sections are determined in the spherical complex potential formalism. The sum of the two gives the total cross section and the total inelastic cross section is used to calculate the total ionization cross sections. The present total and ionization cross sections are found to be consistent with other theories and experimental measurements, where they exist. Our total cross section results for CFx (x = 1-3) radicals presented here are first estimates on these species.

Antony, B. K.; Joshipura, K. N.; Mason, N. J.

2005-02-01

457

Total weight choosability of graphs Tsai-Lien Wong  

E-print Network

Total weight choosability of graphs Tsai-Lien Wong Xuding Zhu Abstract A graph G = (V, E) is called (k, k )-total weight choosable if the following holds: For any total list assignment L which vertices x, x , eE(x) f(e)+f(x) = eE(x ) f(e)+f(x ). We conjecture that every graph is (2, 2)-total weight

Zhu, Xuding

458

Concentration and flux of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids for monitored tributaries of Lake Champlain, 1990-2012  

USGS Publications Warehouse

Annual and daily concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids were estimated for 18 monitored tributaries to Lake Champlain by using the Weighted Regressions on Time, Discharge, and Seasons regression model. Estimates were made for 21 or 23 years, depending on data availability, for the purpose of providing timely and accessible summary reports as stipulated in the 2010 update to the Lake Champlain “Opportunities for Action” management plan. Estimates of concentration and flux were provided for each tributary based on (1) observed daily discharges and (2) a flow-normalizing procedure, which removed the random fluctuations of climate-related variability. The flux bias statistic, an indicator of the ability of the Weighted Regressions on Time, Discharge, and Season regression models to provide accurate representations of flux, showed acceptable bias (less than ±10 percent) for 68 out of 72 models for total and dissolved phosphorus, total nitrogen, and chloride. Six out of 18 models for total suspended solids had moderate bias (between 10 and 30 percent), an expected result given the frequently nonlinear relation between total suspended solids and discharge. One model for total suspended solids with a very high bias was influenced by a single extreme value; however, removal of that value, although reducing the bias substantially, had little effect on annual fluxes.

Medalie, Laura

2014-01-01

459

Spatial variation of total column ozone on a global scale  

Microsoft Academic Search

The spatial dependence of total column ozone varies strongly with latitude, so that homogeneous models (invariant to all rotations) are clearly unsuitable. However, an assumption of axial symmetry, which means that the process model is invariant to rotations about the Earth’s axis, is much more plausible and considerably simplifies the modeling. Using TOMS (Total Ozone Mapping Spectrometer) measurements of total

Michael L. Stein

2007-01-01

460

Total Ownership Cost (TOC) Cost as an Independent Variable  

E-print Network

$ + procurement $ + operation $ + logistical support $ + disposal $ Linked - Indirect Direct Direct Cost Life1 Total Ownership Cost (TOC) and Cost as an Independent Variable (CAIV) Dr. Jeffrey Beach Naval. Definitions: TOC Total Ownership Cost (TOC) ­ Total Ownership Cost includes all costs associated

461

Global Volcano Total Economic Loss Risk Distribution Projection: Robinson  

E-print Network

Global Volcano Total Economic Loss Risk Distribution Projection: Robinson Total Economic Loss is found by weighting the value of GDP exposure to volcanoes for each grid cell by a vulnerability International Bank for Reconstruction and Development/The World Bank and Columbia University. Volcano Total

Columbia University

462

Diabetic Neuropathy: What is a Total Contact Cast?  

MedlinePLUS

MENU Return to Web version Diabetic Neuropathy | What is a Total Contact Cast? What is a total contact cast? A total contact cast is a cast used to treat ulcers (serious, deep sores) on a person’s foot. It consists of a fiberglass shell that fits around your leg and foot very ...

463

Optimized Registration for Computer Assisted Total Knee Arthroplasty  

E-print Network

260 Optimized Registration for Computer Assisted Total Knee Arthroplasty Jon-Michael Tucker, Mc Pennsylvania State University Introduction: Total knee arthroplasty, (TKA), also known as total knee, a cement epoxy is then used to firmly secure the mechanical components that will operate as "new knees

Omiecinski, Curtis

464

Coronal Plane Stability Before and After Total Knee Arthroplasty  

E-print Network

Coronal Plane Stability Before and After Total Knee Arthroplasty Robert A. Siston, PhD*,, ; Stuart of total knee arthroplasty depends in part on proper soft tissue management to achieve a stable joint. It is unknown to what degree total knee arthroplasty changes joint stability. We used a surgical navigation

Delp, Scott

465