OXYGEN UPTAKE BEFORE AND AFTER THE ONSET OF CLAUDICATION DURING A 6-MINUTE WALK TEST

PubMed Central

Gardner, Andrew W.; Ritti-Dias, Raphael M.; Stoner, Julie A.; Montgomery, Polly S.; Khurana, Aman; Blevins, Steve M.

2011-01-01

Purposes To compare oxygen uptake before and after the onset of claudication in subjects with peripheral artery disease (PAD) during a 6-minute walk test, and to identify predictors of the change in oxygen uptake following the onset of claudication pain Methods Fifty subjects with PAD were studied, in which 33 experienced claudication (Pain Group) during a 6-minute walk test, and 17 were pain-free during this test (Pain-Free Group). Oxygen uptake and ambulatory cadence were primary outcomes obtained during the 6-minute walk test. Results The Pain Group experienced onset of claudication pain at 179 ± 45 meters (mean ± standard deviation) and continued to walk to achieve a 6-minute walk distance of 393 ± 74 meters, which was similar (p = 0.74) to the Pain-Free Group (401 ± 76 meters). Oxygen uptake increased (p < 0.0001) after the onset of pain in the Pain Group, and this change was greater (p = 0.025) than the increase in oxygen uptake from the second to fifth minute of walking in the Pain-Free Group. Furthermore, ambulatory cadence decreased after the onset of pain in the Pain Group (p = 0.0003). The change in oxygen uptake was associated with metabolic syndrome (p = 0.0023), 6-minute walk distance (p = 0.0037), age, (p = 0.0041), and the oxygen uptake during the second minute of the test (p = 0.012). Conclusion Claudication increases oxygen uptake of self-paced, over-ground ambulation despite a decrease in cadence. The pain-mediated increase in oxygen uptake was blunted in subjects with metabolic syndrome, suggesting that they have an impaired ability to increase oxygen uptake during ambulation. The clinical significance is that claudication increases metabolic cost of ambulation, thereby increasing the relative intensity of exercise and reducing the tolerance to sustain ambulation. PMID:21890308

A systematic review to evaluate the effectiveness of carnitine supplementation in improving walking performance among individuals with intermittent claudication.

PubMed

Delaney, Christopher L; Spark, J Ian; Thomas, Jolene; Wong, Yew Toh; Chan, Lok Tsung; Miller, Michelle D

2013-07-01

To evaluate the evidence for the use of carnitine supplementation in improving walking performance among individuals with intermittent claudication. Systematic review. An electronic search of the literature was performed using MEDLINE (PubMed), Scopus, Cochrane Central Register of Controlled Trials and The Cochrane Library from inception through to November 2012. Search terms included peripheral arterial disease, intermittent claudication and carnitine. Reference lists of review articles and primary studies were also examined. Full reports of published experimental studies including randomized controlled trials and pre-test/post-test trials were selected for inclusion. A quality assessment was undertaken according to the Jadad scale. A total of 40 articles were retrieved, of which 23 did not meet the inclusion criteria. The 17 included articles reported on a total of 18 experimental studies of carnitine supplementation (5 pre-test/post-test; 8 parallel RCT; 5 cross-over RCT) for improving walking performance in adults with intermittent claudication. For pre-test/post-test studies, 300-2000 mg propionyl-L-carnitine (PLC) was administered orally or intravenously for a maximum of 90 days (7-42 participants) with statistically significant improvements of between 74 m and 157 m in pain free walking distance and between 71 m and 135 m in maximal walking distance across 3 out of 5 studies. Similarly, PLC (600 mg-3000 mg) was administered orally in 7 out of 8 parallel RCTs (22-485 participants), the longest duration being 12 months. All but one of the smallest trials demonstrated statistically significant improvements in walking performance between 31 and 54 m greater than placebo for pain free walking distance and between 9 and 86 m greater than placebo for maximal walking distance. A double-blind parallel RCT of cilostazol plus 2000 mg oral L-carnitine or placebo for 180 days (145 participants) did not demonstrate any significant improvement in walking performance. Of 5 cross-over RCTs (8-20 participants), 4 demonstrated significant improvements in walking performance following administration of 300-6000 mg L-carnitine or PLC. Compared to placebo, pain free walking distance and maximal walking distance improved by 23-132 m and 104 m respectively following carnitine intervention. Most trials demonstrated a small or modest improvement in walking performance with administration of PLC or L-carnitine. These findings were largely independent of level or quality of evidence, while there was some evidence that intravenous administration was more effective than oral administration and those with severe claudication may achieve greater benefits than those with moderate claudication. Routine carnitine supplementation in the form of PLC may therefore be a useful adjunct therapy for management of intermittent claudication. Further research is warranted to determine the optimal form, duration, dose and safety of carnitine supplementation across the spectrum of peripheral arterial disease severity and its effect with concurrent supervised exercise programs and best medical therapy. These studies should be supplemented with cost effectiveness studies to ensure that the return on the investment is acceptable. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

Can claudication be improved with medication?

PubMed

Conners, Michael S; Money, Samuel R

2002-12-01

Intermittent claudication is a common disabling condition that affects approximately 5% to 15% of patients with atherosclerotic disease. Recommended treatment involves lifestyle modification and physical conditioning through the adoption of a regular exercise program. These methods of treatment often have been unsuccessful in the past because of noncompliance, in large part related to the relatively minor degree of improvement experienced by the patient. However, some recent trials have resulted in greater relative improvements in both pain-free and maximal walking distances in some patients treated with medication. Surgical and endovascular options offer greater degrees of improvement but also greater morbidity and should be reserved as treatment for severe claudication. The efficacies, as well as common adverse reactions associated with current medications used to treat patients with intermittent claudication are reviewed. Copyright 2002, Elsevier Science (USA). All rights reserved.

Evaluation of patient compliance, quality of life impact and cost-effectiveness of a "test in-train out" exercise-based rehabilitation program for patients with intermittent claudication.

PubMed

Malagoni, Anna Maria; Vagnoni, Emidia; Felisatti, Michele; Mandini, Simona; Heidari, Mahdi; Mascoli, Francesco; Basaglia, Nino; Manfredini, Roberto; Zamboni, Paolo; Manfredini, Fabio

2011-01-01

Patients with intermittent claudication (IC) could benefit from low-cost, effective rehabilitative programs. This retrospective study evaluates compliance, impact on Quality of Life (QoL) and cost-effectiveness of a hospital prescribed, at-home performed (Test-in/Train-out) rehabilitative program for patients with IC. Two-hundred and eighty-nine patients with IC (71 ± 10.1 years, M = 210) were enrolled for a 2-year period. Two daily 10-min home walking sessions at maximal asymptomatic speed were prescribed, with serial check-ups at the hospital. Compliance with the program was assessed by assigning a score of 1 (lowest compliance) to 4 (highest compliance). The SF-36 questionnaire and a constant-load treadmill test were used to evaluate QoL and Initial/Absolute Claudication Distance, respectively. Both direct and indirect costs of the program were considered for cost-effectiveness analysis. Two-hundred and fifty patients (70.5 ± 9.2 years, M = 191), at Fontaine's II-B stage (86%), were included in the study. No adverse events were reported. The average compliance score was 3.1. At discharge, both SF-36 domains and walking performance significantly increased (P < 0.0001). A total of 1,839 in-hospital check-ups (7.36 /patient) were performed. Direct and indirect costs represented 93% and 7% of the total costs, respectively. The average costs of a visit and of a therapy cycle were C68.93 and C507.20, respectively. The cost to walk an additional meter before stopping was C9.22. A Test-in/Train-out program provided favourable patient compliance, QoL impact and cost-effectiveness in patients with IC.

Sarcopenia in Peripheral Arterial Disease: Prevalence and Effect on Functional Status.

PubMed

Addison, Odessa; Prior, Steven J; Kundi, Rishi; Serra, Monica C; Katzel, Leslie I; Gardner, Andrew W; Ryan, Alice S

2018-04-01

(1) To determine the prevalence of sarcopenia in older men with peripheral arterial disease (PAD); (2) to compare a subgroup of the group with age-, race-, sex-, and body mass index (BMI)-matched non-PAD control counterparts, and (3) to compare the functional status of those with PAD with and without sarcopenia. Cohort study. Medical center. Sedentary community-dwelling men (N=108; age, >50y) with a confirmed diagnosis of PAD (44% blacks; BMI, 27.8±0.4kg/m 2 ; ankle-brachial index, .62±.01). Not applicable. Dual-energy x-ray absorptiometry scans were used to assess appendicular lean mass and determine the prevalence of sarcopenia by/height 2 . Treadmill tests were used to determine claudication onset time, peak walking time, and claudication recovery time. 6-Minute walk distance was also measured. Sarcopenia prevalence in our PAD cohort was 25%. The PAD subgroup (n=42) matched with control counterparts in terms of race, sex, age, and BMI had higher prevalence rates than did their non-PAD counterparts (23.8% vs 2.4%; P<.05). Individuals with sarcopenia (n=28) had a shorter 6-minute walk distance (326±18.8m vs 380±9.7m; P<.05) and higher claudication recovery time (592±98s vs 395±29s; P<.05) than did individuals with PAD but without sarcopenia (n=80). There was no difference in claudication onset time or peak walking time between the PAD groups. Men with PAD demonstrate a high prevalence of sarcopenia. Those with sarcopenia and PAD demonstrate decreased mobility function. Published by Elsevier Inc.

One-Year Outcomes Following Directional Atherectomy of Infrapopliteal Artery Lesions: Subgroup Results of the Prospective, Multicenter DEFINITIVE LE Trial.

PubMed

Rastan, Aljoscha; McKinsey, James F; Garcia, Lawrence A; Rocha-Singh, Krishna J; Jaff, Michael R; Noory, Elias; Zeller, Thomas

2015-12-01

To report a subgroup analysis of the prospective, multicenter, single-arm DEFINITIVE LE trial to assess the effectiveness of directional atherectomy for the treatment of infrapopliteal artery lesions at 1 year. In the DEFINITIVE LE trial, follow-up assessments occurred up to 1 year postprocedure. Of the 800 patients enrolled, 145 subjects with 189 infrapopliteal lesions met the criteria for this analysis. Seventy (48.3%) and 75 (51.7%) patients were suffering critical limb ischemia (CLI) and intermittent claudication, respectively; 68.3% (99/145) had diabetes. The mean lesion length was 58±44 mm (all lesions); 20.2% were occluded. The primary endpoint for patients with claudication was duplex ultrasound-derived primary patency, while for subjects with CLI it was freedom from major amputation of the target limb at 1 year. Endpoints and adverse events were independently assessed. Procedure success (≤30% residual stenosis) was achieved in 84% of treated lesions. The 1-year primary patency rate was 84% (claudicants 89.6% and CLI patients 78%, p=0.11), and the freedom from major amputation rate was 97.1% (claudicants 100% and CLI 93.8%, p=0.03). In both claudication and CLI patients, significant improvements in Rutherford category and objective measures of walking distance and quality of life were seen at 1 year in comparison to baseline. This study demonstrates that directional atherectomy in infrapopliteal arteries results in promising technical and clinical results at 1 year for claudicant as well as CLI patients. © The Author(s) 2015.

Combined aspirin and cilostazol treatment is associated with reduced platelet aggregation and prevention of exercise-induced platelet activation.

PubMed

Cleanthis, M; Bhattacharya, V; Smout, J; Ashour, H; Stansby, G

2009-05-01

Cilostazol has proven efficacy in increasing walking distance in claudicants, but it has not been demonstrated to be more effective than placebo in secondary cardiovascular prevention. The direct effect of exercise on platelet function remains less well defined. We have investigated the effect of combination treatment with aspirin and cilostazol on platelet activity in claudicants subjected to repeated treadmill exercise. Nineteen claudicants completed a double-blind, randomised, controlled, cross-over trial. Each subject received a 2-week course of aspirin (75mg) and placebo and aspirin and cilostazol (100mg twice daily). Following each 2-week treatment period, patients participated in a standardised treadmill test (3.2kmh(-1), 10 degrees incline) walking to maximal claudication distance. The exercise was repeated thrice in total, and blood was sampled before and after exercise. Platelet activation was measured using free platelet counting aggregation, flow cytometry for surface markers of platelet activation and soluble P-selectin assay. Compared to aspirin and placebo, combination treatment with aspirin and cilostazol was associated with reduced arachidonic-acid-induced platelet aggregation (p<0.01, Wilcoxon signed-rank test). Aspirin and placebo treatment were associated with elevated P-selectin expression, platelet-monocyte aggregation and reduced CD42b expression (p<0.05, Wilcoxon signed-rank test) post-exercise. No difference was seen in spontaneous platelet aggregation whilst soluble P-selectin was reduced post-exercise with combination treatment with aspirin and cilostazol (p<0.05, Wilcoxon signed-rank test). Combination treatment with aspirin and cilostazol results in suppression of platelet activation and reduces the effect of exercise on platelets. The benefit seen may be a result of cilostazol enhancing the inhibitory effect of aspirin on the cyclo-oxygenase pathway.

Thermal biofeedback in the treatment of intermittent claudication in diabetes: a case study.

PubMed

Saunders, J T; Cox, D J; Teates, C D; Pohl, S L

1994-12-01

The objective of the present case study was to examine the therapeutic effects of thermal biofeedback-assisted autogenic training on a patient with non-insulin-dependent diabetes mellitus (NIDDM), vascular disease, and symptoms of intermittent claudication. The patient received thermal biofeedback from the hand for five sessions, then from the foot for 16 sessions, while hand and foot skin temperature were monitored simultaneously. In addition, the patient was instructed in autogenic training and practiced daily at home. Follow-up measurements were taken at 12 and 48 months. Within-session foot temperature rose specifically in response to foot temperature biofeedback and starting foot temperature rose between sessions. Posttreatment blood pressure was reduced to a normal level. Attacks of intermittent claudication were reduced to zero after 12 sessions and walking distance increased by about a mile per day over the course of treatment. It would appear that thermal biofeedback and autogenic training are potentially promising therapies for persons with diabetes and peripheral vascular disease.

Predictors of improved quality of life and claudication in patients undergoing spinal cord stimulation for critical lower limb ischemia.

PubMed

Tshomba, Yamume; Psacharopulo, Daniele; Frezza, Serena; Marone, Enrico Maria; Astore, Domenico; Chiesa, Roberto

2014-04-01

The aim of this study was to determine predictors of improved quality of life and claudication in patients undergoing spinal cord stimulation (SCS) for critical lower limb ischemia. We retrospectively analyzed 101 consecutive patients with few meter claudication and nonhealing ulcer who underwent definitive SCS. These patients were selected among 274 SCS patients treated at our center from 1995 to 2012. All presented with non-reconstructable critical leg ischemia (NR-CLI) and underwent supervised exercise therapy, best medical care and regular ulcers standard or advanced medications for at least 1 month before SCS implantation. We measured self-perceived quality of life using the SF-36 questionnaire. Patients with an improved walking distance of at least 30 meters after SCS had significant improvement on SF-36 questionnaire scores. We considered 30 meters as the cut-off for clinically significant improvement in pain-free walking distance, and we defined this value as functional success. Logistic regression was applied to assess baseline and other patient variables as possible predictors of functional success. Neither perioperative mortality nor significant complications were found. At a median follow-up of 69 months (range 1-202 months), mortality, major amputation, and minor amputation were 8.9%, 5.9%, and 6.9%, respectively. Functional clinical success was reported in 25.7% of cases. Independent predictors of functional success at univariate analysis included delay between the onset of the ulcer and SCS (P < 0.001) and the pain-free walking distance before SCS (P < 0.002). The only predictive factor of functional success at multivariate analysis was the delay between the onset of ulcer and SCS (median delay in patients with and without functional success was 3 and 15 months, respectively). In particular, comparable to pain-free walking distance before SCS, the success rate decreased by 40% for each month elapsed from onset of ulcer to SCS. In our series of patients who underwent SCS, reduced delay between the onset of ulcer and SCS was associated with improved quality of life and walking distance. Larger series are required to confirm these data and to assess clinical implications. Copyright © 2014 Elsevier Inc. All rights reserved.

[Treatment of severe intermittent claudication: ORACLE-PGE1 short term study. A randomised 40-week study. Evaluation of efficacy and costs].

PubMed

Cesarone, M R; Belcaro, G; Nicolaides, A N; Griffin, M; Geroulakos, G; Ramaswami, G; Cazaubon, M; Barsotti, A; Vasdekis, S; Christopoulos, D; Agus, G; Bavera, P; Mondani, P; Ippolito, E; Flenda, F

2002-12-01

The efficacy and cost of prostaglandin E1 (PGE1) in severe intermittent claudication was studied comparing a long-term protocol (LTP) with a short-term protocol (STP) in a randomised 40-week study. Phase 1 was a 2-week run-in phase (no treatment) for both protocols. In LTP, phase 2 was the main treatment phase. Treatment was performed with 2-hour infusions (60 micro g PGE1, 5 days each week for 4 weeks. In phase 3 (4-week interval period), PGE1 was administered twice a week (same dosage). In phase 4 (40 weeks), no PGE1 were used. In STP, phase 2 treatment was performed in two days by a 2-hour infusion (60 micro g PGE1 twice a day in 2 days). The same cycle was repeated every 4 weeks. A treadmill test was performed at inclusion, at the beginning of each phase and at the end of weeks 12, 16, 20 32 and 40. A progressive training plan (walking) and reduction in risk factors plan was used in both groups. Out of the 1276 included patients 1165 completed the study (606 in LTP group; 559 in the STP). Drop-outs were 111. The two groups were comparable in distribution, risk factors and smoking. Intention-to-treat analysis indicated an increase in pain free walking distance (PFWD). The absolute and percent increase in pain-free walking distance (PFWD) was comparable in both LTP and STP groups with a significative increase in TWD at 4 weeks. At 20 and 40 weeks increase was up to 219% in the LTP and 460% in the STP group (p<0.02). Comparable results concerning PFWD were obtained in the two groups. Both treatments were well tolerated. No side effect was observed. Local effects were observed in 8.5% of the treated subjects in the LTP and 4% in the STP. The average cost of the LTP protocol was 8786 Euro. For STP the costs was 946 (10.8% of LTP). For both protocols the cost of the infusion was 24% of the total for the LTP and 35% in the STP. Therefore 75% of the cost is not drug-related. In conclusion between-group-analysis favours STP considering walking distance and costs. Results indicate good efficacy and tolerability of PGE1 treatment particularly STP.

Unilateral repetitive tibial nerve stimulation improves neurogenic claudication and bilateral F-wave conduction in central lumbar spinal stenosis.

PubMed

Nakajima, Noritsuna; Tani, Toshikazu; Kiyasu, Katsuhito; Kumon, Masashi; Taniguchi, Shinichirou; Takemasa, Ryuichi; Tadokoro, Nobuaki; Nishida, Kazuya; Ikeuchi, Masahiko

2018-03-01

Repetitive electrical nerve stimulation of the lower limb may improve neurogenic claudication in patients with lumbar spinal stenosis (LSS) as originally described by Tamaki et al. We tested if this neuromodulation technique affects the F-wave conduction on both sides to explore the underlying physiologic mechanisms. We studied a total of 26 LSS patients, assigning 16 to a study group receiving repetitive tibial nerve stimulation at the ankle (RTNS) on one leg, and 10 to a group without RTNS. RTNS conditioning consisted of a 0.3-ms duration square-wave pulse with an intensity 20% above the motor threshold, delivered at a rate of 5 Hz for 5 min. All patients underwent the walking test and the F-wave and M-wave studies for the tibial nerve on both sides twice; once as the baseline, and once after either the 5-min RTNS or 5-min rest. Compared to the baselines, a 5-min RTNS increased claudication distance (176 ± 96 m vs 329 ± 133 m; p = 0.0004) and slightly but significantly shortened F-wave minimal onset latency (i.e., increased F-wave conduction velocity) not only on the side receiving RTNS (50.7 ± 4.0 ms vs 49.2 ± 4.2 ms; p = 0.00081) but also on the contralateral side (50.1 ± 4.6 ms vs 47.9 ± 4.2 ms; p = 0.011). A 5-min rest in the group not receiving RTNS neither had a significant change on claudication distance nor on any F-wave measurements. The M response remained unchanged in both groups. The present study verified a beneficial effect of unilaterally applied RTNS of a mild intensity on neurogenic claudication and bilateral F-wave conduction. Our F-wave data suggest that this type of neuromodulation could be best explained by an RTNS-induced widespread sympathetic tone reduction with vasodilation, which partially counters a walking-induced further decline in nerve blood flow in LSS patients who already have ischemic cauda equina. Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Sciatica and claudication caused by ganglion cyst.

PubMed

Yang, Guang; Wen, Xiaoyu; Gong, Yubao; Yang, Chen

2013-12-15

Case report. We report a rare case that a ganglion cyst compressed the sciatic nerve and caused sciatica and claudication in a 51-year-old male. Sciatica and claudication commonly occurs in spinal stenosis. To our knowledge, only 4 cases have been reported on sciatica resulting from posterior ganglion cyst of hip. A 51-year-old male had a 2-month history of radiating pain on his right leg. He could only walk 20 to 30 m before stopping and standing to rest for 1 to 3 minutes. Interestingly, he was able to walk longer distances (about 200 m) when walking slowly in small steps, without any rest. He had been treated as a case of lumbar disc herniation, but conservative treatment was ineffective. On buttock examination, a round, hard, and fixative mass was palpated at the exit of the sciatic nerve. MR imaging of hip revealed a multilocular cystic mass located on the posterior aspect of the superior gemellus and obturator internus, compressing the sciatic nerve. On operation, we found that the cyst extended to the superior gemellus and the obturator internus, positioned right at the outlet of the sciatic nerve. At 18 months of follow-up, the patient continued to be symptom free. He returned to comprehensive physical activity with no limitations. For an extraspinal source, a direct compression on the sciatic nerve also resulted in sciatica and claudication. A meticulous physical examination is very important for the differential diagnosis of extraspinal sciatica from spinal sciatica.

Are the barriers for physical activity practice equal for all peripheral artery disease patients?

PubMed

Cavalcante, Bruno R; Farah, Breno Q; dos A Barbosa, João Paulo; Cucato, Gabriel Grizzo; da Rocha Chehuen, Marcel; da Silva Santana, Fábio; Wolosker, Nelson; de Moraes Forjaz, Cláudia Lúcia; Ritti-Dias, Raphael M

2015-02-01

To investigate barriers to physical activity related to the sociodemographic comorbidities and clinical variables of patients with intermittent claudication. Cross-sectional study. Ambulatory care. The medical histories of patients (N=145) aged ≥50 years with intermittent claudication were examined. Not applicable. Sociodemographic data (sex, race, level of education, socioeconomic status, marital status), comorbidities (overweight, hypertension, dyslipidemia, diabetes, currently smoking, heart disease), and clinical variables (initial claudication distance, total walking distance, ankle-brachial index). Information on personal and environmental barriers was obtained by questionnaire. Low economic status was most associated with "being afraid of falling" (odd ratios [OR]=2.22; 95% confidence interval [CI], 1.08-4.54). Low education level was most associated with "lack of street pedestrian crossing" (OR=3.34; 95% CI, 1.48-7.52). Diabetes was associated with lack of energy (OR=3.38; 95% CI, 1.68-6.79) and other medical conditions (eg, arthritis, angina) (OR=3.44; 95% CI, 1.65-7.16). Ankle brachial index was associated with "some difficulty in getting to a place where physical activity can be performed" (OR=2.75; 95% CI, 1.22-6.21). Walking capacity was strongly associated with barriers relating to leg pain (OR=7.39; 95% CI, 1.66-32.88). Older patients, those with a low education level, patients with diabetes, low ankle brachial index, and those with a lower walking capacity are more likely to experience barriers to physical activity. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Changes in Function After a 6-Month Walking Intervention in Patients With Intermittent Claudication Who Are Obese or Nonobese.

PubMed

Addison, Odessa; Ryan, Alice S; Prior, Steven J; Katzel, Leslie I; Kundi, Rishi; Lal, Brajesh K; Gardner, Andrew W

Both obesity and peripheral artery disease (PAD) limit function and may work additively to reduce mobility. The purpose of this study was to compare the effects of a 6-month, center-based walking program on mobility function between adults who are weight-stable obese and nonobese with PAD. This is a secondary data analysis of 2 combined studies taken from previous work. Fifty-three adults with PAD and intermittent claudication participated in 6 months of treadmill training or standard of care. Patients were divided into 4 groups for analyses: exercise nonobese (Ex), exercise obese (ExO), standard-of-care nonobese (SC), and standard-of-care obese (SCO). Mobility was assessed by a standardized treadmill test to measure claudication onset time (COT) and peak walking time (PWT) as well as the distance walked during a 6-minute walk distance (6MWD) test. There was a significant (P < .001) interaction (intervention × obesity) effect on 6MWD, wherein both exercise groups improved (Ex = 7%, ExO = 16%; P < .02), the SC group did not change (0.9%; P > .05), and the SCO group tended to decline (-18%; P = .06). Both exercise intervention groups significantly improved COT (Ex = 92%, ExO = 102%; P < .01) and PWT (Ex = 54%, ExO = 103%; P < .001). There was no change (P > .05) in either standard-of-care group. Individuals who are obese and nonobese with PAD made similar improvements after a 6-month, center-based walking program. However, patients who are obese with PAD and do not exercise may be susceptible to greater declines in mobility. Exercise may be particularly important in patients who are obese with PAD to avoid declines in mobility.

[Double-blind randomized comparative study of nicergoline naftidrofuryl on the quality of life in chronic obliterative arteriopathy of lower limbs with intermittent claudication].

PubMed

Meilhac, B; Montestruc, F; Aubin, F; Djian, F; Rouffy, J

1997-01-01

The functional limitation of patients with obliterative arterial disease, and with intermittent claudication, damages their quality of life. The purpose of this trial was to compare the effects of nicergoline and naftidrofuryl on the quality of life and the functional discomfort of the 131 patients with claudication. It was a multicentre, randomised, double-blind trial with parallel groups. The patients were asked to complete a quality of life questionnaire and a Visual Analogue Scale, and to evaluate the number of steps on flat ground before the pain began. After 6 months of treatment, we observed, for all treatments combined, a significant improvement (p = 0.0001) in the quality of life and in the functional discomfort. Three variables favoured nicergoline: the estimated time before the onset of the pain (p = 0.003), the functional discomfort quantified by the Visual Analogue Scale (p < 0.05), the distance covered on flat ground (p = 0.013). The other variables, and especially the total score on the self-questionnaire, confirmed this impression, without reaching significance (p = 0.136). The data suggest that in terms of quality of life nicergoline is superior. The clinical tolerance is good and comparable between the two treatments.

The reliability of differentiating neurogenic claudication from vascular claudication based on symptomatic presentation.

PubMed

Nadeau, Mélissa; Rosas-Arellano, M Patricia; Gurr, Kevin R; Bailey, Stewart I; Taylor, David C; Grewal, Ruby; Lawlor, D Kirk; Bailey, Chris S

2013-12-01

Intermittent claudication can be neurogenic or vascular. Physicians use a profile based on symptom attributes to differentiate the 2 types of claudication, and this guides their investigations for diagnosis of the underlying pathology. We evaluated the validity of these symptom attributes in differentiating neurogenic from vascular claudication. Patients with a diagnosis of lumbar spinal stenosis (LSS) or peripheral vascular disease (PVD) who reported claudication answered 14 questions characterizing their symptoms. We determined the sensitivity, specificity and positive and negative likelihood ratios (PLR and NLR) for neurogenic and vascular claudication for each symptom attribute. We studied 53 patients. The most sensitive symptom attribute to rule out LSS was the absence of "triggering of pain with standing alone" (sensitivity 0.97, NLR 0.050). Pain alleviators and symptom location data showed a weak clinical significance for LSS and PVD. Constellation of symptoms yielded the strongest associations: patients with a positive shopping cart sign whose symptoms were located above the knees, triggered with standing alone and relieved with sitting had a strong likelihood of neurogenic claudication (PLR 13). Patients with symptoms in the calf that were relieved with standing alone had a strong likelihood of vascular claudication (PLR 20.0). The classic symptom attributes used to differentiate neurogenic from vascular claudication are at best weakly valid independently. However, certain constellation of symptoms are much more indicative of etiology. These results can guide general practitioners in their evaluation of and investigation for claudication.

The relationship of walking distances estimated by the patient, on the corridor and on a treadmill, and the Walking Impairment Questionnaire in intermittent claudication.

PubMed

Frans, Franceline Alkine; Zagers, Marjolein B; Jens, Sjoerd; Bipat, Shandra; Reekers, Jim A; Koelemay, Mark J W

2013-03-01

Physicians and patients consider the limited walking distance and perceived disability when they make decisions regarding (invasive) treatment of intermittent claudication (IC). We investigated the relationship between walking distances estimated by the patient, on the corridor and on a treadmill, and the Walking Impairment Questionnaire (WIQ) in patients with IC due to peripheral arterial disease. This was a single-center, prospective observational cohort study at a vascular laboratory in a university hospital in the Netherlands. The study consisted of 60 patients (41 male) with a median age of 64 years (range, 44-86 years) with IC and a walking distance ≤ 250 m on a standardized treadmill test. Main outcome measures were differences and Spearman rank correlations between pain-free walking distance, maximum walking distance (MWD) estimated by the patient, on the corridor and on a standardized treadmill test, and their correlation with the WIQ. The median patients' estimated, corridor, and treadmill MWD were 200, 200, and 123, respectively (P < .05). Although the median patients' estimated and corridor MWD were not significantly different, there was a difference on an individual basis. The correlation between the patients' estimated and corridor MWD was moderate (r = 0.61; 95% confidence interval [CI], 0.42-0.75). The correlation between patients' estimated and treadmill MWD was weak (r = 0.39; 95%, CI 0.15-0.58). Respective correlations for the pain-free walking distance were comparable. The patients' estimated MWD was moderately correlated with WIQ total score (r = 0.63; 95%, CI 0.45-0.76) and strongly correlated with WIQ distance score (r = 0.81; 95% CI, 0.69-0.88). The correlation between the corridor MWD and WIQ distance score was moderate (r = 0.59; 95% CI, 0.40-0.74). Patients' estimated walking distances and on a treadmill do not reflect walking distances in daily life. Instruments that take into account the perceived walking impairment, such as the WIQ, may help to better guide and evaluate treatment decisions. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Effect of diabetes mellitus on walking distance parameters after supervised exercise therapy for intermittent claudication: A systematic review.

PubMed

Hageman, David; Gommans, Lindy Nm; Scheltinga, Marc Rm; Teijink, Joep Aw

2017-02-01

Some believe that certain patients with intermittent claudication may be unsuitable for supervised exercise therapy (SET), based on the presence of comorbidities and the possibly increased risks. We conducted a systematic review (MEDLINE, EMBASE and CENTRAL) to summarize evidence on the potential influence of diabetes mellitus (DM) on the response to SET. Randomized and nonrandomized studies that investigated the effect of DM on walking distance after SET in patients with IC were included. Considered outcome measures were maximal, pain-free and functional walking distance (MWD, PFWD and FWD). Three articles met the inclusion criteria ( n = 845). In one study, MWD was 111 meters (128%) longer in the non-DM group compared to the DM group after 3 months of follow-up ( p = 0.056). In a second study, the non-DM group demonstrated a significant increase in PFWD (114 meters, p ⩽ 0.05) after 3 months of follow-up, whereas there was no statistically significant increase for the DM group (54 meters). On the contrary, the largest study of this review did not demonstrate any adverse effect of DM on MWD and FWD after SET. In conclusion, the data evaluating the effects of DM on SET were inadequate to determine if DM impairs the exercise response. While trends in the data do not suggest an impairment, they are not conclusive. Practitioners should consider this limitation when making clinical decisions.

A Three Month Home Exercise Programme Augmented with Nordic Poles for Patients with Intermittent Claudication Enhances Quality of Life and Continues to Improve Walking Distance and Compliance After One Year.

PubMed

Oakley, C; Spafford, C; Beard, J D

2017-05-01

The objective of this study was to collect 1 year follow-up information on walking distance, speed, compliance, and cost in patients with intermittent claudication who took part in a previously reported 12 week randomised clinical trial of a home exercise programme augmented with Nordic pole walking versus controls who walked normally. A second objective was to look at quality of life and ankle brachial pressure indices (ABPIs) after a 12 week augmented home exercise programme. Thirty-two of the 38 patients who completed the original trial were followed-up after 6 and 12 months. Frequency, duration, speed, and distance of walking were recorded using diaries and pedometers. A new observational cohort of 29 patients was recruited to the same augmented home exercise programme. ABPIs, walking improvement, and quality of life questionnaire were recorded at baseline and 12 weeks (end of the programme). Both groups in the follow-up study continued to improve their walking distance and speed over the following year. Compliance was excellent: 98% of the augmented group were still walking with poles at both 6 and 12 months, while 74% of the control group were still walking at the same point. The augmented group increased their mean walking distance to 17.5 km by 12 months, with a mean speed of 4.2 km/hour. The control group only increased their mean walking distance from 4.2 km to 5.6 km, and speed to 3.3 km/hour. Repeated ANOVA showed the results to be highly significant (p = .002). The 21/29 patients who completed the observational study showed a statistically significant increase in resting ABPIs from baseline (mean ± SD 0.75 ± 0.12) to week 12 (mean ± SD 0.85 ± 0.12) (t = (20) -8.89, p = .000 [two-tailed]). All their walking improvement and quality of life parameters improved significantly (p = .002 or less in the six categories) over the same period and their mean health scores improved by 79%. Following a 12 week augmented home exercise programme, most patients with intermittent claudication continued to significantly improve their walking distance and walking speed at 1 year compared with normal walking. Quality of life and ABPIs improved significantly after only 12 weeks and it is postulated that the improvement in ABPI was due to collateral development. These results justify the belief that an augmented home exercise programme will be as clinically effective as existing supervised exercise programmes, with the added benefits of lower cost and better compliance. Funding for a multicentre trial comparing an augmented home exercise programme with existing supervised exercise programme is now urgently required. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

The severity of muscle ischemia during intermittent claudication.

PubMed

Egun, Anselm; Farooq, Vasim; Torella, Francesco; Cowley, Richard; Thorniley, Maureen S; McCollum, Charles N

2002-07-01

The degree of ischemia during intermittent claudication is difficult to quantify. We evaluated calf muscle ischemia during exercise in patients with claudication with near infrared spectroscopy. A Critikon Cerebral Redox Model 2001 (Johnson & Johnson Medical, Newport, Gwent, United Kingdom) was used to measure calf muscle deoxygenated hemoglobin (HHb), oxygenated hemoglobin (O(2)Hb), and total hemoglobin levels and oxygenation index (HbD; HbD = O(2)Hb - HHb) in 16 patients with claudication and in 14 control subjects before, during, and after walking on a treadmill for 1 minute (submaximal exercise). These measures were repeated after a second maximal exercise in patients with claudication and after 7 minutes walking in control subjects. Near-infrared spectroscopy readings during maximal exercise were then compared with a model of total ischemia induced with tourniquet in 16 young control subjects. Total hemoglobin level changed little during exercise in both patients with claudication and control subjects. HHb levels rose, and O(2)Hb level and HbD falls were more pronounced in patients with claudication than in control subjects after submaximal and maximal exercise. During maximal exercise, HbD fell markedly by a median (interquartile range) of 210.5 micromol/cm (108.2 to 337.0 micromol/cm) in patients with claudication compared with 66.0 micromol/cm (44.0 to 101.0 micromol/cm) in elderly control subjects and 41.0 micromol/cm (36.0 to 65.0 micromol/cm) in young control subjects (P <.001). This fall also was greater than the HbD fall induced with tourniquet ischemia at 90.8 micromol/cm (57.6 to 126.2 micromol/cm; P =.006). Hemoglobin desaturation in exercising calf muscle is profound in patients with claudication, considerably greater even than that induced with three minutes of tourniquet occlusion. Further studies are necessary to investigate the relationship between the inflammatory response and near-infrared spectroscopy during exercise in patients with claudication.

Lower functional capacity is associated with higher cardiovascular risk in Brazilian patients with intermittent claudication.

PubMed

Gengo e Silva, Rita de Cassia; de Melo, Vanessa Ferreira Amorim; Wolosker, Nelson; Consolim-Colombo, Fernanda Marciano

2015-03-01

The purpose of this study was to examine the association between cardiovascular risk estimated by the Framingham Risk Score and functional capacity in patients with peripheral artery disease using a 6-minute walk test. Fifty-six participants with intermittent claudication were recruited. The Framingham Risk Score was calculated and used to split the participants into two groups: Group A (mild and moderate risk) and group B (severe risk). The ankle-brachial index (ABI) was calculated for each leg using a handheld Doppler probe. Walking ability was verified by a 6-minute walk test. Descriptive statistics were used to describe the sample's demographic and clinical characteristics. To compare clinical data between the two groups, a t test or Mann-Whitney test was used as appropriate according to the type of variable being analyzed. The Pearson coefficient was used to verify the association between cardiovascular risk and functional capacity. Group A had 19 participants (60.5 ± 6.3 years; 36.8% male) and group B had 37 participants (63.4 ± 8.7 years; 73% male). No differences were observed when comparing the ABI between both groups. The total distances covered by the men in group A were shorter compared with those of group B (331.4 + 51.5 vs 257.9 + 84.0; P = .02). The cardiovascular risk score was negative and was significantly correlated with total distances for men (r = -0.53; P = .001) and with pain-free distances for women (r = -0.46; P = .03). Functional capacity, evaluated through a 6-minute walk test, seems to be associated with 10-year total mortality risk. Copyright © 2015 Society for Vascular Nursing, Inc. Published by Elsevier Inc. All rights reserved.

Calf Muscle Oxygen Saturation During Six-Minute Walk Test And Its Relationship With Walking Impairment In Symptomatic Peripheral Artery Disease.

PubMed

Andrade-Lima, Aluísio; Cucato, Gabriel G; Domingues, Wagner J R; Germano-Soares, Antônio H; Cavalcante, Bruno R; Correia, Marilia A; Saes, Glauco F; Wolosker, Nelson; Gardner, Andrew W; Zerati, Antônio E; Ritti-Dias, Raphael M

2018-05-21

Impaired microcirculation is associated with poor walking capacity in symptomatic peripheral artery disease (PAD) patients during treadmill test, however, this test does not simulate the efforts of daily walking of these patients. Thus, the aim of the study was to describe the microcirculation responses during six-minute walk test (6MWT) and to analyze the relationship between microcirculation indicators and walking impairment in symptomatic PAD patients. Thirty-four patients were included (mean age = 67.6 ± 11.2). The clinical characteristics were collected and they performed a 6MWT in which initial claudication distance (ICD) and total walking distance (TWD) were recorded. During and after the 6MWT, calf muscle oxygen saturation (StO 2 ) parameters were monitored continuously to measure microcirculation behavior. The association between calf muscle StO 2 parameters and walking impairment was analyzed by Pearson or Spearman correlations. Walking impairment was not associated with any StO 2 parameters during exercise. In contrast, after 6MWT, recovery time of StO 2 (r = -0.472, P = .008) and recovery time to maximal StO 2 (r= -0.402, P = .019) were negatively correlated with ICD. Furthermore, the distance walked under claudication symptoms (ΔTWD - ICD) was positively correlated with recovery time to maximal StO 2 (r = 0.347, P = .048). In symptomatic PAD patients, shorter ICD values during a 6MWT are associated with a delayed recovery in calf muscle StO 2 after exercise. Calf muscle StO 2 parameters decrease subtly during 6MWT, suggesting that the degree of ischemia in the calf muscle during ground walking, simulating efforts of the daily walking, is relatively low. Copyright © 2018 Elsevier Inc. All rights reserved.

Peripheral arterial disease decreases muscle torque and functional walking capacity in elderly.

PubMed

Dziubek, Wioletta; Bulińska, Katarzyna; Stefańska, Małgorzata; Woźniewski, Marek; Kropielnicka, Katarzyna; Jasiński, Tomasz; Jasiński, Ryszard; Pilch, Urszula; Dąbrowska, Grażyna; Skórkowska-Telichowska, Katarzyna; Wojcieszczyk-Latos, Joanna; Kałka, Dariusz; Janus, Agnieszka; Zywar, Katarzyna; Paszkowski, Rafał; Szuba, Andrzej

2015-08-01

The aim of this study is to compare values of force-velocity and functional walking capacity in elderly patients with intermittent claudication with respect to the control group. The study involved 135 individuals: 85-peripheral arterial disease (PAD) group diagnosed with stage II chronic lower limb ischemia, according to Fontaine's classification, and 50-control group. The studies included an assessment of walking capacity using a six-minute walk test (6MWT) and measurement of force-velocity parameters (peak torque-PTQ, total work-TW, average power-AVGP) of the lower limbs obtained by means of a functional dynamometry under isokinetic conditions. The peripheral arterial disease group is characterized by significantly lower values of force-velocity parameters compared to the control group (p<0.005). Walking capacity in this group is significantly reduced due to significant differences in the distance covered (p<0.0001), walking speed (p<0.01), and its intensity (p<0.01). Further, a positive correlation was found between the maximum distance specified in the six-minute walk test and lower limb muscle strength in the isokinetic test. Mean values of all force-velocity parameters and walk distance were significantly higher in the control group than in the peripheral arterial disease group. In the PAD group, in both men and women, the value of the agonist/antagonist ratio of both lower limbs are lower in men and women comparing to the control group. A rehabilitation program for patients with intermittent claudication must consider exercises improving strength, exercise capacity, and endurance in patients with PAD. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Sagittal plane joint kinetics during stair ascent in patients with peripheral arterial disease and intermittent claudication.

PubMed

King, Stephanie L; Vanicek, Natalie; O'Brien, Thomas D

2017-06-01

Stair negotiation poses a substantial physical demand on the musculoskeletal system and this challenging task can place individuals at risk of falls. Peripheral arterial disease (PAD) can cause intermittent claudication (IC) pain in the calf and results in altered gait mechanics during level walking. However, whether those with PAD-IC adopt alternate strategies to climb stairs is unknown. Twelve participants with PAD-IC (six bilateral and six unilateral) and 10 healthy controls were recruited and instructed to ascend a five-step staircase whilst 3D kinematic data of the lower-limbs were recorded synchronously with kinetic data from force plates embedded into the staircase on steps two and three. Limbs from the unilateral group and both limbs from the bilateral claudicants were categorised as claudicating (N=18), asymptomatic (N=6) and control (N=10). Claudicants walked more slowly than healthy controls (trend; P=<0.066). Both claudicating- and asymptomatic-limb groups had reduced propulsive GRF (P=0.025 and P=0.002, respectively) and vertical GRF (P=0.005 and P=0.001, respectively) compared to controls. The claudicating-limb group had a reduced knee extensor moment during forward continuance (P=0.060), ankle angular velocity at peak moment (P=0.039) and ankle power generation (P=0.055) compared to the controls. The slower gait speed, irrespective of laterality of symptoms, indicates functional capacity was determined by the limitations of the claudicating limb. Reduced ankle power generation and angular velocity (despite adequate plantarflexor moment) implies velocity-dependent limitations existed in the calf. The lack of notable compensatory strategies indicates reliance on an impaired muscle group to accomplish this potentially hazardous task, highlighting the importance of maintaining plantarflexor strength and power in those with PAD-IC. Copyright © 2017 Elsevier B.V. All rights reserved.

[Consensus diagnosis and treatment of arterial intermittent claudication. Central Guidance Organization for Peer Review].

PubMed

Kitslaar, P J

1997-12-06

Intermittent claudication is an indicator of increased risk of cardiac and cerebrovascular morbidity and mortality and as such a reason to look for modifiable risk factors for atherosclerosis. A vascular anamnesis and physical examination can reliably exclude presence of peripheral arterial occlusive disease in the lower extremities, but cannot reliably demonstrate its presence. Certainty about presence or absence of peripheral arterial occlusive disease can be obtained by determination of an ankle-brachial blood pressure index. The main method for the diagnosis of severity and localisation of stenoses and occlusions in the arteries to the legs is the echo-Doppler (duplex) examination. With this method the feasibility of percutaneous transluminal angioplasty (PTA) can also be determined. Consequently, angiography has lost importance as a diagnostic method and is only still indicated as part of an interventional treatment (operation or PTA). Treatment should be aimed at both amelioration of symptoms and reduction of risk factors for atherosclerosis. A key-stone of the treatment is cessation of smoking. The role of pharmacotherapy in reducing symptomatology is only limited. Walking exercise can have a positive effect on walking distance and should always be tried. PTA is the treatment modality of first choice for stenoses in the aortoiliac and femoropopliteal arteries. For segmental occlusions in the iliac pathway, also recanalisation by means of PTA (in combination with stent placement) is a justifiable treatment option. In all other cases operative revascularisations give good functional results. Invasive treatments for patients with intermittent claudication should be performed within a multidisciplinary team.

Auricular vagal nerve stimulation in peripheral arterial disease patients.

PubMed

Hackl, Gerald; Prenner, Andreas; Jud, Philipp; Hafner, Franz; Rief, Peter; Seinost, Gerald; Pilger, Ernst; Brodmann, Marianne

2017-10-01

Auricular nerve stimulation has been proven effective in different diseases. We investigated if a conservative therapeutic alternative for claudication in peripheral arterial occlusive disease (PAD) via electroacupuncture of the outer ear can be established. In this prospective, double-blinded trial an ear acupuncture using an electroacupuncture device was carried out in 40 PAD patients in Fontaine stage IIb. Twenty patients were randomized to the verum group using a fully functional electroacupuncture device, the other 20 patients received a sham device (control group). Per patient, eight cycles (1 cycle = 1 week) of electroacupuncture were performed. The primary endpoint was defined as a significantly more frequent doubling of the absolute walking distance after eight cycles in the verum group compared to controls in a standardized treadmill testing. Secondary endpoints were a significant improvement of the total score of the Walking Impairment Questionnaire (WIQ) as well as improvements in health related quality of life using the Short Form 36 Health Survey (SF-36). There were no differences in baseline characteristics between the two groups. The initial walking distance significantly increased in both groups (verum group [means]: 182 [95 % CI 128-236] meters to 345 [95 % CI 227-463] meters [+ 90 %], p < 0.01; control group [means]: 159 [95 % CI 109-210] meters to 268 [95 % CI 182-366] meters [+ 69 %], p = 0.01). Twelve patients (60 %) in the verum group and five patients (25 %) in controls reached the primary endpoint of doubling walking distance (p = 0.05). The total score of WIQ significantly improved in the verum group (+ 22 %, p = 0.01) but not in controls (+ 8 %, p = 0.56). SF-36 showed significantly improvements in six out of eight categories in the verum group and only in one of eight in controls. Electroacupuncture of the outer ear seems to be an easy-to-use therapeutic option in an age of increasingly invasive and mechanically complex treatments for PAD patients.

Subanalysis of the CONFIRM Registries: Acute Procedural Outcomes in Claudicant and Critical Limb Ischemia Patients With Varying Levels of Calcification Treated for Peripheral Arterial Disease With Orbital Atherectomy.

PubMed

Adams, George L; Das, Tony; Lee, Michael S; Beasley, Robert; Mustapha, Jihad

2015-11-01

Patients with peripheral arterial disease (PAD) can be classified into groups based upon the severity of the disease using the Rutherford classification system. This analysis compares the procedural outcomes of PAD patients treated with orbital atherectomy stratified by Rutherford class (1-3 = intermittent claudication; 4-6 = critical limb ischemia [CLI]), and acute angiographic outcomes of these patients stratified by degree of lesion calcification. The CONFIRM registry series was analyzed and included 1697 patients with intermittent claudication (Rutherford class 1-3) and 1320 patients with CLI (Rutherford class 4-6) treated with orbital atherectomy. The composite rate of dissection, perforation, slow-flow, vessel closure, spasm, embolism, and thrombus formation was compared between claudicants and CLI patients with varying degrees of lesion calcification. Patients with CLI were older and had a higher prevalence of diabetes, coronary artery disease, and renal disease (P<.001). Claudicants with moderately/severely calcified lesions had a lower rate of dissection (both non-flow limiting and flow-limiting) than claudicants with mildly/minimally calcified lesions. CLI patients with mildly/minimally calcified lesions had higher rates of embolism and thrombus than CLI patients with moderately/severely calcified lesions. Plaque modification with orbital atherectomy resulted in similar low procedural complication rates in the CLI group compared with the claudicant group. These results suggest that orbital atherectomy is safe and effective for treating calcified lesions in high-risk patients with varying severity of PAD symptoms.

The effect of exercise on coagulation and fibrinolysis factors in patients with peripheral arterial disease.

PubMed

Patelis, Nikolaos; Karaolanis, Georgios; Kouvelos, Georgios N; Hart, Collin; Metheiken, Sean

2016-09-01

Peripheral arterial disease is a widely prevalent atherosclerotic occlusive disorder. Symptoms commence with exercise-induced pain in the lower extremities, known as claudication. Despite the fact that exercise has been shown to improve fibrinolytic profile some patients, the effect of exercise on coagulation and fibrinolysis cascades in claudicants has not been comprehensively defined. Literature search in English language yielded 13 studies of exercise on claudicants, including 420 patients. Claudicants tend to have a higher coagulation activity at rest compared to healthy individuals, a trend that persists even after exercise. Post-exercise coagulation activity of claudicants is increased when compared to their respective baseline levels, but it is so in a non-consistent manner. From the available data, it has been suggested that claudicants have a functional and effective fibrinolytic mechanism in place, operating continuously at a relatively higher activity level compared to healthy individuals. Fibrinolysis seems to be activated by exercise; a positive outcome with a prolonged effect as shown by a few of the studies. A final conclusion whether coagulation or fibrinolysis activity is affected mostly by exercise type and intensity in claudicants could not be answered. All conclusions regarding the effect of exercise on the coagulation and fibrinolysis mechanisms should be taken under cautious consideration, due to the limited number of studies, the small number of patients and the different exercise strategies employed in each study. Further randomized studies with similar exercise protocols could provide safer conclusions in the future. © 2016 by the Society for Experimental Biology and Medicine.

The impact of clinical, psychological, behavioral, social, and environmental factors on self-perceived symptom severity in a male cohort with intermittent claudication.

PubMed

Sharath, Sherene E; Kougias, Panos; Pisimisis, George; Barshes, Neal R

2016-05-01

To understand the relationship between self-perceived severity of intermittent claudication and various associated nonclinical factors, we examined how correlates in domains of physical activity (ie, clinical, psychological, behavioral, social, and environmental factors) relate to exertional limb symptoms. A survey was administered to individuals with intermittent claudication during their initial outpatient assessment. The subjects' self-reported exertional limb symptom severity and classic-versus-atypical claudication classification was based on the Walking Impairment Questionnaire (WIQ) and San Diego Claudication Questionnaire (SDCQ), respectively. We evaluated psychosocial and environmental factors, osteoarthritis symptoms, health, behaviors, and beliefs. Logistic and linear regressions identified factors with a strong independent association with total WIQ scores and the SDCQs. A cohort of 102 subjects (99.0% male) was enrolled in the study. The median age was 65 years with a median ankle-brachial index of 0.69. Forty-three subjects (43%) had "typical" claudication per SDCQs. Individuals with atypical claudication were more likely to report higher Aberdeen Clinical Back Pain Questionnaire scores (odds ratio, 1.04; P = .04) and no depressive symptoms (odds ratio, 8.30; P = .03). Exertional limb symptom severity among the entire cohort was significantly associated with increasing osteoarthritis symptoms (P <.001), age (P = .02), a reserved personality (P = .008), and the belief that an exercise regimen would not improve symptoms (P = .005), self-perceived levels of boredom (P = .002), and the belief that exercise (P = .002) was the best way to improve symptoms were associated with decreased symptom severity. When restricted to those with atypical pain, significant factors associated with increasing exertional symptom severity included age greater than 60 years (P = .005), osteoarthritis (P = .02), alcohol use (P = .01), belief that exercise would not improve walking (P = .03), and difficulty walking around the neighborhood (P = .02). When restricted to those with classic claudication, significant factors associated with increasing exertional limb symptom severity included frequent pain or aching in the calves while walking or sitting (P = .03 [walking]; P = .01 [sitting]) and occasional morning joint stiffness (P = .007). Exertional limb symptom severity was also associated with high limitations at home (P = .003) and a belief that exercise would not improve walking (P = .005) among those with classic claudication. Symptom severity and type of pain are associated with a number of nonclinical factors. A multidomain approach, as indicated by the models above, would benefit the continuum of care for intermittent claudication, where management is integrated and coordinated among multiple lines of care. Published by Elsevier Inc.

Peripheral vascular disease: consequence for survival and association with risk factors in the Speedwell prospective heart disease study.

PubMed Central

Bainton, D; Sweetnam, P; Baker, I; Elwood, P

1994-01-01

OBJECTIVE--To measure the prevalence and incidence of intermittent claudication, to describe the mortality associated wtih the condition, and to assess the relevance of risk factors for vascular disease. DESIGN--A standard questionnaire on calf pain when walking was given in the prospective Speedwell study, and a range of risk factors were measured. The men were re-examined at intervals of three years, and deaths over 11 years were identified. SETTING--The general population. PARTICIPANTS--All men aged 45 to 59 registered with 16 general practitioners. RESULTS--The prevalence of intermittent claudication increased from almost nil at ages 45-49 to 2.9% at ages 60-64. The annual incidence increased from 0.3% in the youngest men to 0.5% in those in their early 60s. Intermittent claudication was related to the existence of ischaemic heart disease, particularly angina, at the first examination. The relative odds of men with angina developing intermittent claudication was 6.7 (95% confidence interval (95% CI) 3.6 to 12.4). The risk of death in men with intermittent claudication was substantially raised. After standardisation for age and smoking the relative odds of death was 3.8 (95% CI 2.2 to 6.5). The excess was entirely from circulatory causes. Systolic blood pressure, fasting plasma glucose, triglycerides, and white cell count were all independently associated with the development of intermittent claudication, but the most striking association was with smoking. CONCLUSIONS--Intermittent claudication is an indicator for a very high risk of death. This is only partly explained by its strong association with ischaemic heart disease. PMID:7917683

Ginkgo

MedlinePlus

... intermittent claudication (leg pain caused by narrowing arteries), tinnitus, and other health problems. Ginkgo is made into ... enhancement in healthy people, blood pressure, intermittent claudication, tinnitus, age-related macular degeneration, the risk of having ...

Lumbar vertebral hemangioma causing cauda equina syndrome: a case report.

PubMed

Ahn, Henry; Jhaveri, Subir; Yee, Albert; Finkelstein, Joel

2005-11-01

Case report. To report a case of lumbar hemangioma causing neurogenic claudication and early cauda equina, managed with hemostatic vertebroplasty and posterior decompression. This is the first report to our knowledge of a lumbar hemangioma causing neurogenic claudication and early cauda equina syndrome. Most hemangiomas causing neurologic symptoms occur in thoracic spine and cause spinal cord compression. Vertebroplasty as a method of hemostasis and for providing mechanical stability in this situation has not been discussed previously in the literature. L4 hemangioma was diagnosed in a 64-year-old woman with severe neurogenic claudication and early cauda equina syndrome. Preoperative angiograms showed no embolizable vessels. Posterior decompression was performed followed by bilateral transpedicular vertebroplasty. The patient received postoperative radiation to prevent recurrence. Complete relief of neurogenic claudication and cauda equina with less than 100 mL of blood loss. A lumbar hemangioma of the vertebral body, although rare, can cause neurogenic claudication and cauda equina syndrome. Intraoperative vertebroplasty can be an effective method of hemostasis and provide stability of the vertebra following posterior decompression.

The effect of pharmacological treatment on gait biomechanics in peripheral arterial disease patients

PubMed Central

2010-01-01

Background Pharmacological treatment has been advocated as a first line therapy for Peripheral Arterial Disease (PAD) patients suffering from intermittent claudication. Previous studies document the ability of pharmacological treatment to increase walking distances. However, the effect of pharmacological treatment on gait biomechanics in PAD patients has not been objectively evaluated as is common with other gait abnormalities. Methods Sixteen patients were prescribed an FDA approved drug (Pentoxifylline or Cilostazol) for the treatment of symptomatic PAD. Patients underwent baseline gait testing prior to medication use which consisted of acquisition of ground reaction forces and kinematics while walking in a pain free state. After three months of treatment, patients underwent repeat gait testing. Results Patients with symptomatic PAD had significant gait abnormalities at baseline during pain free walking as compared to healthy controls. However, pharmacological treatment did not produce any identifiable alterations on the biomechanics of gait of the PAD patients as revealed by the statistical comparisons performed between pre and post-treatment and between post-treatment and the healthy controls. Conclusions Pharmacological treatment did not result in statistically significant improvements in the gait biomechanics of patients with symptomatic PAD. Future studies will need to further explore different cohorts of patients that have shown to improve significantly their claudication distances and/or their muscle fiber morphology with the use of pharmacological treatment and determine if this is associated with an improvement in gait biomechanics. Using these methods we may distinguish the patients who benefit from pharmacotherapy and those who do not. PMID:20529284

Real-Time and Meter-Scale Absolute Distance Measurement by Frequency-Comb-Referenced Multi-Wavelength Interferometry.

PubMed

Wang, Guochao; Tan, Lilong; Yan, Shuhua

2018-02-07

We report on a frequency-comb-referenced absolute interferometer which instantly measures long distance by integrating multi-wavelength interferometry with direct synthetic wavelength interferometry. The reported interferometer utilizes four different wavelengths, simultaneously calibrated to the frequency comb of a femtosecond laser, to implement subwavelength distance measurement, while direct synthetic wavelength interferometry is elaborately introduced by launching a fifth wavelength to extend a non-ambiguous range for meter-scale measurement. A linearity test performed comparatively with a He-Ne laser interferometer shows a residual error of less than 70.8 nm in peak-to-valley over a 3 m distance, and a 10 h distance comparison is demonstrated to gain fractional deviations of ~3 × 10 -8 versus 3 m distance. Test results reveal that the presented absolute interferometer enables precise, stable, and long-term distance measurements and facilitates absolute positioning applications such as large-scale manufacturing and space missions.

Real-Time and Meter-Scale Absolute Distance Measurement by Frequency-Comb-Referenced Multi-Wavelength Interferometry

PubMed Central

Tan, Lilong; Yan, Shuhua

2018-01-01

We report on a frequency-comb-referenced absolute interferometer which instantly measures long distance by integrating multi-wavelength interferometry with direct synthetic wavelength interferometry. The reported interferometer utilizes four different wavelengths, simultaneously calibrated to the frequency comb of a femtosecond laser, to implement subwavelength distance measurement, while direct synthetic wavelength interferometry is elaborately introduced by launching a fifth wavelength to extend a non-ambiguous range for meter-scale measurement. A linearity test performed comparatively with a He–Ne laser interferometer shows a residual error of less than 70.8 nm in peak-to-valley over a 3 m distance, and a 10 h distance comparison is demonstrated to gain fractional deviations of ~3 × 10−8 versus 3 m distance. Test results reveal that the presented absolute interferometer enables precise, stable, and long-term distance measurements and facilitates absolute positioning applications such as large-scale manufacturing and space missions. PMID:29414897

Absolute Distance Measurement with the MSTAR Sensor

NASA Technical Reports Server (NTRS)

Lay, Oliver P.; Dubovitsky, Serge; Peters, Robert; Burger, Johan; Ahn, Seh-Won; Steier, William H.; Fetterman, Harrold R.; Chang, Yian

2003-01-01

The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. The sensor uses a single laser in conjunction with fast phase modulators and low frequency detectors. We describe the design of the system - the principle of operation, the metrology source, beamlaunching optics, and signal processing - and show results for target distances up to 1 meter. We then demonstrate how the system can be scaled to kilometer-scale distances.

High prevalence of known and unknown pulmonary diseases in patients with claudication during exercise oximetry: A retrospective analysis.

PubMed

Colas-Ribas, Christophe; Signolet, Isabelle; Henni, Samir; Feuillloy, Mathieu; Gagnadoux, Frédéric; Abraham, Pierre

2016-10-01

The prevalence of pulmonary disease in patients with peripheral artery disease (PAD) has not been extensively studied. Recent evidence has shown that ∼20% of the patients have an atypical chest transcutaneous oxygen pressure (TcpO2) pattern during exercise, which suggests walking-induced hypoxemia. The main objectives of this study were to: (1) describe in a retrospective way the characteristics of the patients suffering from claudication, who attended a treadmill testing in our laboratory, (2) assess the prevalence of known or unknown pulmonary disease. The second aim of this study was to evaluate the impact of the therapeutic interventions on the walking capacities, after treatment, of the eventually detected pulmonary disorders.We retrospectively analyzed 1482 exercise TcpO2 test results. Patients that had no history of pulmonary disease, but either reported severe dyspnea or showed atypical profiles on their chest exercise-TcpO2, were advised to refer to the department of pneumology for additional investigations.In addition to the 166 patients with a history of pulmonary disease, 158 patients were suspected of unknown pulmonary disease from the result of their TcpO2 test. Many patients (n = 99/158, 62.7%) did not attend a pulmonologist visit. A pulmonary disease was established in 55 (93.2%) of the other 59 patients. Obstructive sleep apnea syndrome (OSAS) was the one and only diagnosis retained in 42/59 patients (71.2%). Among the 47 patients who had a second evaluation of their walking capacity on treadmill, 38 had treatment of the pulmonary disease found, vascular surgery treatment or a severe restricted diet, 9 had no treatment. Only the "treated" group showed a significant improvement in the maximal walking distance on treadmill between the 2 evaluations, 313 ± 251 m to 433 ± 317 m (P = 0.03).This retrospective pilot study underlines the high prevalence of both known and unknown pulmonary disease in patients whose primary complaint was lower limb claudication. Systematic screening and treatment of pulmonary disease in patients with claudication might be justified, to improve walking ability of such patients and possibly reduce or delay the requirement for revascularization. Prospective studies are required to confirm these preliminary results.

Wearable Sensor Technology Efficacy in Peripheral Vascular Disease (wSTEP): A Randomized Controlled Trial.

PubMed

Normahani, Pasha; Kwasnicki, Richard; Bicknell, Colin; Allen, Louise; Jenkins, Mike P; Gibbs, Richard; Cheshire, Nicholas; Darzi, Ara; Riga, Celia

2017-05-11

To evaluate the effect of using wearable activity monitors (WAMs) in patients with intermittent claudication (IC) within a single-center randomized controlled trial. WAMs allow users to set daily activity targets and monitor their progress. They may offer an alternative treatment to supervised exercise programs (SEPs) for patients with IC. Thirty-seven patients with IC were recruited and randomized into intervention or control group. The intervention consisted of a feedback-enabled, wrist-worn activity monitor (WAM) in addition to access to SEP. The control group was given access to SEP only. The outcome measures were maximum walking distance (MWD), claudication distance (CD), and quality of life as measured by the VascuQol questionnaire. Participants were assessed upon recruitment, and at 3, 6, and 12 months. Patients in the WAM group showed significant improvement in MWD at 3 and 6 months (80-112 m, to 178 m; P < 0.001), which was sustained at 12 months. The WAM group also increased CD (40 vs 110 m; P < 0.001) and VascuQol score (4.7 vs 5.8; P = 0.004). The control group saw a temporary increase in VascuQol score at 6 months (4.5 vs 4.7; P = 0.028), but no other improvements in MWD or CD were observed. Significantly higher improvements in MWD were seen in the WAM group compared with that in the control group at 6 months (82 vs -5 m; P = 0.009, r = 0.47) and 12 months (69 vs 7.5 m; P = 0.011, r = 0.52). The study demonstrates the significant, sustained benefit of WAM-led technologies for patients with IC. This potentially resource-sparing intervention is likely to provide a valuable adjunct or alternative to SEP.

Global Positioning System Use in the Community to Evaluate Improvements in Walking After Revascularization

PubMed Central

Gernigon, Marie; Le Faucheur, Alexis; Fradin, Dominique; Noury-Desvaux, Bénédicte; Landron, Cédric; Mahe, Guillaume; Abraham, Pierre

2015-01-01

Abstract Revascularization aims at improving walking ability in patients with arterial claudication. The highest measured distance between 2 stops (highest-MDCW), the average walking speed (average-WSCW), and the average stop duration (average-DSCW) can be measured by global positioning system, but their evolution after revascularization is unknown. We included 251 peripheral artery diseased patients with self-reported limiting claudication. The patients performed a 1-hour stroll, recorded by a global positioning system receiver. Patients (n = 172) with confirmed limitation (highest-MDCW <2000m) at inclusion were reevaluated after 6 months. Patients revascularized during the follow-up period were compared with reference patients (ie, with unchanged lifestyle medical or surgical status). Other patients (lost to follow-up or treatment change) were excluded (n = 89). We studied 44 revascularized and 39 reference patients. Changes in highest-MDCW (+442 vs. +13 m) and average-WSCW (+0.3 vs. −0.2 km h−1) were greater in revascularized than in reference patients (both P < 0.01). In contrast, no significant difference in average-DSCW changes was found between the groups. Among the revascularized patients, 13 (29.5%) had a change in average-WSCW, but not in highest-MDCW, greater than the mean + 1 standard deviation of the change observed for reference patients. Revascularization may improve highest-MDCW and/or average-WSCW. This first report of changes in community walking ability in revascularized patients suggests that, beyond measuring walking distances, average-WSCW measurement is essential to monitor these changes. Applicability to other surgical populations remains to be evaluated. Registration: http://www.clinicaltrials.gov/ct2/show/NCT01141361 PMID:25950694

Global positioning system use in the community to evaluate improvements in walking after revascularization: a prospective multicenter study with 6-month follow-up in patients with peripheral arterial disease.

PubMed

Gernigon, Marie; Le Faucheur, Alexis; Fradin, Dominique; Noury-Desvaux, Bénédicte; Landron, Cédric; Mahe, Guillaume; Abraham, Pierre

2015-05-01

Revascularization aims at improving walking ability in patients with arterial claudication. The highest measured distance between 2 stops (highest-MDCW), the average walking speed (average-WSCW), and the average stop duration (average-DSCW) can be measured by global positioning system, but their evolution after revascularization is unknown.We included 251 peripheral artery diseased patients with self-reported limiting claudication. The patients performed a 1-hour stroll, recorded by a global positioning system receiver. Patients (n = 172) with confirmed limitation (highest-MDCW <2000m) at inclusion were reevaluated after 6 months. Patients revascularized during the follow-up period were compared with reference patients (ie, with unchanged lifestyle medical or surgical status). Other patients (lost to follow-up or treatment change) were excluded (n = 89).We studied 44 revascularized and 39 reference patients. Changes in highest-MDCW (+442 vs. +13 m) and average-WSCW (+0.3 vs. -0.2 km h) were greater in revascularized than in reference patients (both P < 0.01). In contrast, no significant difference in average-DSCW changes was found between the groups. Among the revascularized patients, 13 (29.5%) had a change in average-WSCW, but not in highest-MDCW, greater than the mean + 1 standard deviation of the change observed for reference patients.Revascularization may improve highest-MDCW and/or average-WSCW. This first report of changes in community walking ability in revascularized patients suggests that, beyond measuring walking distances, average-WSCW measurement is essential to monitor these changes. Applicability to other surgical populations remains to be evaluated. http://www.clinicaltrials.gov/ct2/show/NCT01141361.

Effectiveness of a Medical vs Revascularization Intervention for Intermittent Leg Claudication Based on Patient-Reported Outcomes.

PubMed

Devine, Emily B; Alfonso-Cristancho, Rafael; Yanez, N David; Edwards, Todd C; Patrick, Donald L; Armstrong, Cheryl A L; Devlin, Allison; Symons, Rebecca G; Meissner, Mark H; Derrick, Ellen L T; Lavallee, Danielle C; Kessler, Larry G; Flum, David R

2016-10-19

Intermittent claudication (IC) is the most common presentation of infrainguinal peripheral artery disease. Both medical and revascularization interventions for IC aim to increase walking comfort and distance, but there is inconclusive evidence of the comparative benefit of revascularization given the possible risk of limb loss. To compare the effectiveness of a medical (walking program, smoking cessation counseling, and medications) vs revascularization (endovascular or surgical) intervention for IC in the community, focusing on outcomes of greatest importance to patients. Longitudinal (12-month follow-up) prospective observational cohort study conducted between July 3, 2011, and November 5, 2014, at 15 clinics associated with 11 hospitals in Washington State. Participants were 21 years or older with newly diagnosed or established IC. Medical or revascularization interventions. Primary end points were 12-month change scores on the distance, speed, and stair-climb domains of the Walking Impairment Questionnaire (score range, 0-100). Secondary outcomes were change scores on the Walking Impairment Questionnaire pain domain (score range, 0-100), Vascular Quality of Life Questionnaire (VascuQol) (score range, 1-7), European Quality of Life-5 Dimension Questionnaire (EQ-5D) (score range, 0-1), and Claudication Symptom Instrument (CSI) (score range, 0-4). A total of 323 adults were enrolled, with 282 (87.3%) in the medical cohort. At baseline, the mean duration of disease was longer for participants in the medical cohort, while those in the revascularization cohort reported more severe disease. Other characteristics were well balanced. At 12 months, change scores in the medical cohort reached significance for the following 3 outcomes: speed (5.9; 95% CI, 0.5-11.3; P = .03), VascuQol (0.28; 95% CI, 0.08-0.49; P = .008), and EQ-5D (0.038; 95% CI, 0.011-0.066; P = .006). In the revascularization cohort, there were significant improvements in the following 7 outcomes: distance (19.5; 95% CI, 7.9-31.0; P = .001), speed (12.1; 95% CI, 1.4-22.8; P = .03), stair climb (11.4; 95% CI, 1.3-21.5; P = .03), pain (20.7; 95% CI, 11.0-30.4; P < .001), VascuQol (1.10; 95% CI, 0.80-1.41; P < .001), EQ-5D (0.113; 95% CI, 0.067-0.159; P < .001), and CSI (-0.63; 95% CI, -0.96 to -0.31; P < .001). Relative improvements (percentage changes) at 12 months in the revascularization cohort over the medical cohort were observed as follows: distance (39.1%), speed (15.6%), stair climb (9.7%), pain (116.9%), VascuQol (41%), EQ-5D (18%), and CSI (13.5%). Among patients with IC, those in the revascularization cohort had significantly improved function (Walking Impairment Questionnaire), better health-related quality of life (VascuQol and EQ-5D), and fewer symptoms (CSI) at 12 months compared with those in the medical cohort, providing important information to inform treatment strategies in the community.

High-performance multi-channel fiber-based absolute distance measuring interferometer system

NASA Astrophysics Data System (ADS)

Deck, Leslie L.

2009-08-01

I describe the principle of operation and performance of a fiber-based absolute distance measuring interferometer system with 60 independent simultaneous channels. The system was designed for demanding applications requiring passive, electrically immune sensors with an extremely long MTTF. In addition to providing better than 0.3nm measurement repeatability at 5KHz for all channels, the system demonstrated absolute distance uncertainty of less than 5nm over a 500 micron measurement range.

The Claudication: Exercise Vs. Endoluminal Revascularization (CLEVER) study: rationale and methods.

PubMed

Murphy, Timothy P; Hirsch, Alan T; Ricotta, John J; Cutlip, Donald E; Mohler, Emile; Regensteiner, Judith G; Comerota, Anthony J; Cohen, David J

2008-06-01

Intermittent claudication is the primary symptom of peripheral arterial disease, affecting between 1 and 3 million Americans. Symptomatic improvement can be achieved by endovascular revascularization, but such procedures are invasive, expensive, and may be associated with procedural adverse events. Medical treatment options, including claudication medications and supervised exercise training, are also known to be effective, albeit also with associated limitations. The CLEVER (Claudication: Exercise Vs. Endoluminal Revascularization) study, funded by the Heart, Lung, and Blood Institute of the National Institutes of Health, is a prospective, multicenter, randomized, controlled clinical trial evaluating the relative efficacy, safety, and health economic impact of four treatment strategies for people with aortoiliac peripheral arterial disease and claudication. The treatment arms are: (1) optimal medical care (claudication pharmacotherapy); (2) primary stent placement; (3) supervised exercise rehabilitation; and (4) combined stenting with supervised exercise rehabilitation. The CLEVER study is a 5-year randomized, controlled clinical trial to be conducted at approximately 25 centers in the United States that will monitor 252 patients and their responses to treatment during an 18-month follow-up period. The primary end point is change in maximum walking duration on a graded treadmill test. Secondary end points include the change at 18 months in maximum walking duration from baseline, comparisons of free-living daily activity levels assessed by pedometer, health-related quality of life, and cost-effectiveness. Other analyses include the effect of these treatment strategies on anthropomorphic and physiologic variables, including body mass index, waist circumference, blood pressure, pulse pressure, and resting pulse as well as biochemical markers of cardiovascular health, including fasting lipids, fibrinogen, C-reactive protein, and hemoglobin A 1c values.

Dynamic frequency-domain interferometer for absolute distance measurements with high resolution

NASA Astrophysics Data System (ADS)

Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

2014-11-01

A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution.

Smoking Habits of Patients Undergoing Treatment for Intermittent Claudication in the Vascular Quality Initiative.

PubMed

Gabel, Joshua; Jabo, Brice; Patel, Sheela; Kiang, Sharon; Bianchi, Christian; Chiriano, Jason; Teruya, Theodore; Abou-Zamzam, Ahmed M

2017-10-01

Society for Vascular Surgery practice guidelines for the medical treatment of intermittent claudication give a GRADE 1A recommendation for smoking cessation. Active smoking is therefore expected to be low in patients suffering from intermittent claudication selected for vascular surgical intervention. The aim of this study is to evaluate the prevalence of smoking in patients undergoing intervention for intermittent claudication at the national level and to determine the relationship between smoking status and intervention. The Vascular Quality Initiative (VQI) registries for infra-inguinal bypass, supra-inguinal bypass, and peripheral vascular intervention (PVI) were queried to identify patients who underwent invasive treatment for intermittent claudication. Patient factors, procedure type (bypass versus PVI), and level of disease (supra-inguinal versus infra-inguinal) were evaluated for associations with smoking status (active smoking or nonsmoking) by univariate and covariate analysis. Between 2010 and 2015, 101,055 procedures were entered in the 3 registries, with 40,269 (40%) performed for intermittent claudication. Complete data for analysis were present in 37,632 cases. At the time of intervention, 44% of patients were active smokers, with wide variation by regional quality group (16-53%). In covariate analysis, active smoking at treatment was associated with age <70 years (prevalence ratio [PR] 2.42), male gender (PR 1.03), chronic obstructive pulmonary disease (PR 1.35), absence of prior cardiovascular procedures (PR 1.15), poor medication usage (PR 1.10), preoperative ankle-brachial index (ABI) <0.9 (PR 1.19), and supra-inguinal disease (PR 1.14). Invasiveness of treatment (PVI versus bypass procedures) was not significantly associated with smoking status. During follow-up, 36% of patients had quit smoking. Predictors of smoking cessation included age ≥70 years (RR 1.45), ABI ≥0.9 (RR 1.12), and bypass procedures (RR 1.22). At the time of treatment, 44% of patients undergoing intervention for intermittent claudication in the VQI were active smokers and there was a wide regional variation. Prevalence of active smoking was greater in the presence of younger age, fewer comorbidities, lower ABI, and supra-inguinal disease. Type of procedure performed, and in turn level of invasiveness required, did not appear to be influenced by smoking status. Elderly patients and those undergoing open procedures were more likely to quit smoking during follow up. These findings suggest opportunities for greater smoking cessation efforts before invasive therapies for intermittent claudication. Copyright © 2017 Elsevier Inc. All rights reserved.

Cilostazol prevents foot ulcers in diabetic patients with peripheral vascular disease.

PubMed

de Franciscis, Stefano; Gallelli, Luca; Battaglia, Luigi; Molinari, Vincenzo; Montemurro, Rossella; Stillitano, Domenico M; Buffone, Gianluca; Serra, Raffaele

2015-06-01

Diabetic patients are at high risk of foot ulcerations that may lead to limb amputations with important socio-economic impact. Peripheral vascular disease may be frequently associated in diabetes mellitus type II with its main symptom, intermittent claudication. Many studies reported the known efficacy of cilostazol in treating vascular claudication. Metalloproteinase-9 (MMP-9) seems to be a biochemical marker implicated in chronic wounds and in particular in diabetic foot ulcers. Cilostazol appears to have a lowering effect on MMP-9 levels and this may suggest a beneficial effect in order to prevent or retard the onset of foot ulcer in diabetic patients. In our study, two groups of diabetic patients with peripheral vascular disease were divided into two groups according to the presence of claudication in order to receive cilostazol. Group A (31 patients without claudication) were not eligible to receive cilostazol whereas Group B (47 patients with claudication) received cilostazol administration for 24 weeks (100 mg orally twice daily). Median follow up was of 16 months. During the follow up, 4·25% of patients of Group B and 35·48% of patients of Group A (P < 0·01) showed onset of foot ulceration. Although further randomised and controlled studies are required cilostazol seems to show beneficial effects for primary prevention of diabetic foot ulcers. © 2013 The Authors. International Wound Journal © 2013 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

The correction of vibration in frequency scanning interferometry based absolute distance measurement system for dynamic measurements

NASA Astrophysics Data System (ADS)

Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

2015-10-01

Absolute distance measurement systems are of significant interest in the field of metrology, which could improve the manufacturing efficiency and accuracy of large assemblies in fields such as aircraft construction, automotive engineering, and the production of modern windmill blades. Frequency scanning interferometry demonstrates noticeable advantages as an absolute distance measurement system which has a high precision and doesn't depend on a cooperative target. In this paper , the influence of inevitable vibration in the frequency scanning interferometry based absolute distance measurement system is analyzed. The distance spectrum is broadened as the existence of Doppler effect caused by vibration, which will bring in a measurement error more than 103 times bigger than the changes of optical path difference. In order to decrease the influence of vibration, the changes of the optical path difference are monitored by a frequency stabilized laser, which runs parallel to the frequency scanning interferometry. The experiment has verified the effectiveness of this method.

Objective determination of the predefined duration of a constant-load diagnostic tests in arterial claudication.

PubMed

Mahe, Guillaume; Abraham, Pierre; Zeenny, Maya; Bruneau, Antoine; Vielle, Bruno; Leftheriotis, Georges

2010-04-01

The predefined duration to arbitrarily stop the tests during constant-load treadmill exercise is a subject of debate and widely variable in the literature. We hypothesized that the upper and lower limits for predefined durations of constant-load 3.2 km/hour 10% grade tests could be derived from the distribution of walking distances observed on a treadmill in a population of subjects referred for claudication or from the optimal cutoff point distance on a treadmill to confirm a limitation self-reported by history. We conducted a retrospective analysis using a referral center, institutional practice, and ambulatory patients. We studied 1290 patients (86% male), 62.1 +/- 11.2 years of age, 169 +/- 8 cm height, 75.7 +/- 14.2 kg weight. Patients performed a standard constant-load treadmill test: 3.2 km hour(-1), 10% slope, maximized to 1000 meters (approximately 20 minutes). We analyzed the maximal walking distance self-reported (MWD(SR)) by history and the maximal walking distance measured on the treadmill (MWD(TT)). Patients reporting MWD(SR) >or=1000 meters were considered unlimited by history. Only 197 patients (15.3%) completed the 20-minute treadmill test. Among the 504 patients who did not stop before 250 meters, 47.8% stopped within the next 250 meters (were unable to walk 500 meters). This proportion falls to 7.5% among the 213 patients who did not stop before 750 meters. When the final goal was to estimate whether the treadmill test can discriminate patients with or without limitation by history, area under the receiver operating characteristic (ROC) curve was 0.809 +/- 0.016 (95% confidence interval [CI], 0.778-0.841; P < .0001), the best diagnostic performance was attained for an MWD(TT) of 299 meters (approximately 6.15 minutes). In patients undergoing constant-load treadmill exercise with a protocol of 3.2 km hour(-1) and 10% slope: a predefined duration of 7 minutes could be proposed as a lower limit for the predefined duration of the tests specifically if one aims at confirming the limitation by history with treadmill testing. Owing to the low risk that patients that could walk 750 meters (approximately 15 minutes) will have to stop in the next 250 meters, 15 minutes seems a reasonable upper limit for the predefined test duration in clinical routine.

Development of an in-fiber white-light interferometric distance sensor for absolute measurement of arbitrary small distances.

PubMed

Majumdar, Ayan; Huang, Haiying

2008-05-20

The fabrication, implementation, and evaluation of an in-fiber white-light interferometric distance sensor that is capable of measuring the absolute value of an arbitrary small distance are presented. Taking advantage of the mode-coupling effect of a long-period fiber grating, an additional cavity distance is added to the optical path difference of the distance sensor; therefore, it can generate a sufficient number of fringes for distance demodulation even if the free-space cavity distance is very small. It is experimentally verified that the distance sensor is capable of measuring small distances that are beyond the capability of a Fabry-Perot interferometric distance sensor.

MSTAR: an absolute metrology sensor with sub-micron accuracy for space-based applications

NASA Technical Reports Server (NTRS)

Peters, Robert D.; Lay, Oliver P.; Dubovitsky, Serge; Burger, Johan P.; Jeganathan, Muthu

2004-01-01

The MSTAR sensor is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with subnanometer accuracy.

External-to-Internal Iliac Stent-Graft: Medium-Term Patency Following Exclusion of a Retrogradely Perfused Common Iliac Aneurysm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nicholls, Marcus John, E-mail: marcusnicholls@hotmail.co; McPherson, Simon

2010-08-15

Following complicated aortic aneurysm surgery a complete left iliac occlusion resulted in buttock claudication. A retrogradely perfused right common iliac aneurysm expanded. Exclusion was by external-to-internal iliac stent-graft. No deterioration in claudication occurred with medium-term stent-graft patency.

Clinical Features and Endovascular Management of Iliac Artery Fibromuscular Dysplasia

PubMed Central

Ketha, Siva S.; Bjarnason, Haraldur; Oderich, Gustavo S.; Misra, Sanjay

2014-01-01

Purpose To identify the spectrum of clinical presentation of iliac artery fibromuscular dysplasia (FMD) and to evaluate the outcomes of endovascular management of iliac FMD for claudication. Methods and materials All patients in our institution with a diagnosis of FMD between January 1980 and December 2010 were identified. 14 patients were found to have FMD of the iliac arteries. Associated risk factors included hypertension (79%), hyperlipidemia (64%), smoking history (36%), coronary artery disease (21%), diabetes (0 %), and obesity (36%). Results Eight (57%) patients were incidentally found to have iliac FMD on imaging. 6 (43%) patients had life style limiting claudication involving one or both extremities. All 6 patients were reported as mild peripheral arterial disease (PAD) based on ankle brachial index (ABI) measurements (0.7 to 0.9). These six patients underwent 10 endovascular procedures for claudication including angioplasty (n=8) and self-expanding stent placement (n=2). Mean symptom free survival was 56.3 months. Conclusion Iliac FMD may be found incidentally or may present with disabling claudication that is amenable to endovascular treatment. PMID:24768236

Iliac Artery Stent Placement Relieves Claudication in Patients with Iliac and Superficial Femoral Artery Lesions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ichihashi, Shigeo, E-mail: shigeoichihashi@yahoo.co.jp; Higashiura, Wataru; Itoh, Hirofumi

Purpose. To evaluate the efficacy of iliac artery stent placement for relief of claudication in patients with both iliac and superficial femoral artery (SFA) lesions. Methods. Stent placement for only iliac artery occlusive disease was performed in 94 limbs (74 patients) with both iliac and SFA occlusive disease on the same limb. All procedures were performed because intermittent claudication did not improve after continuation of antiplatelet medication therapy and home-based exercise for 3 months. Rutherford classification was 2 in 20 limbs and 3 in 74 limbs. Patients with critical limb ischemia were excluded. Median duration of follow-up was 40 months.more » Primary patency rates of the iliac stent, clinical improvement rates, and risk factors for requiring additional SFA procedures were evaluated. Results. Primary patency rates of the iliac stent at 1, 3, 5, and 7 years were 97, 93, 79, and 79 %, respectively. The initial clinical improvement rate was 87 %. Continued clinical improvement rates at 1, 3, 5, and 7 years were 87, 81, 69, and 66 %, respectively. SFA Trans-Atlantic Inter-Society Consensus (TASC) II C/D lesion was a significant risk factor for requiring additional SFA procedures. Conclusion. Intermittent claudication was relieved by iliac stent placement in most patients with both iliac and SFA lesions. Thus, the indications for treatment of the SFA intended for claudicants should be evaluated after treatment of the iliac lesion.« less

Design of the multicenter standardized supervised exercise training intervention for the claudication: exercise vs endoluminal revascularization (CLEVER) study.

PubMed

Bronas, Ulf G; Hirsch, Alan T; Murphy, Timothy; Badenhop, Dalynn; Collins, Tracie C; Ehrman, Jonathan K; Ershow, Abby G; Lewis, Beth; Treat-Jacobson, Diane J; Walsh, M Eileen; Oldenburg, Niki; Regensteiner, Judith G

2009-11-01

The CLaudication: Exercise Vs Endoluminal Revascularization (CLEVER) study is the first randomized, controlled, clinical, multicenter trial that is evaluating a supervised exercise program compared with revascularization procedures to treat claudication. In this report, the methods and dissemination techniques of the supervised exercise training intervention are described. A total of 217 participants are being recruited and randomized to one of three arms: (1) optimal medical care; (2) aortoiliac revascularization with stent; or (3) supervised exercise training. Of the enrolled patients, 84 will receive supervised exercise therapy. Supervised exercise will be administered according to a protocol designed by a central CLEVER exercise training committee based on validated methods previously used in single center randomized control trials. The protocol will be implemented at each site by an exercise committee member using training methods developed and standardized by the exercise training committee. The exercise training committee reviews progress and compliance with the protocol of each participant weekly. In conclusion, a multicenter approach to disseminate the supervised exercise training technique and to evaluate its efficacy, safety and cost-effectiveness for patients with claudication due to peripheral arterial disease (PAD) is being evaluated for the first time in CLEVER. The CLEVER study will further establish the role of supervised exercise training in the treatment of claudication resulting from PAD and provide standardized methods for use of supervised exercise training in future PAD clinical trials as well as in clinical practice.

Cost-effectiveness of supervised exercise, stenting, and optimal medical care for claudication: results from the Claudication: Exercise Versus Endoluminal Revascularization (CLEVER) trial.

PubMed

Reynolds, Matthew R; Apruzzese, Patricia; Galper, Benjamin Z; Murphy, Timothy P; Hirsch, Alan T; Cutlip, Donald E; Mohler, Emile R; Regensteiner, Judith G; Cohen, David J

2014-11-11

Both supervised exercise (SE) and stenting (ST) improve functional status, symptoms, and quality of life compared with optimal medical care (OMC) in patients with claudication. The relative cost-effectiveness of these strategies is not well defined. The Claudication: Exercise Versus Endoluminal Revascularization (CLEVER) study randomized patients with claudication due to aortoiliac stenosis to a 6-month SE program, to ST, or to OMC. Participants who completed 6-month follow-up (n=98) were included in a health economic analysis through 18 months. Costs were assessed using resource-based methods and hospital billing data. Quality-adjusted life-years were estimated using the EQ-5D. Markov modeling based on the in-trial results was used to explore the impact of assumptions about the longer term durability of observed differences in quality of life. Through 18 months, mean healthcare costs were $5178, $9804, and $14 590 per patient for OMC, SE, and ST, respectively. Measured quality-adjusted life-years through 18 months were 1.04, 1.16, and 1.20. In our base case analysis, which assumed that observed differences in quality of life would dissipate after 5 years, the incremental cost-effectiveness ratios were $24 070 per quality-adjusted life-year gained for SE versus OMC, $41 376 for ST versus OMC, and $122 600 for ST versus SE. If the treatment effect of ST was assumed to be more durable than that of SE, the incremental cost-effectiveness ratio for ST versus SE became more favorable. Both SE and ST are economically attractive by US standards relative to OMC for the treatment of claudication in patients with aortoiliac disease. ST is more expensive than SE, with uncertain incremental benefit. www.clinicaltrials.gov, Unique identifier: NCT00132743. © 2014 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Imaging popliteal artery disease in young adults with claudication: self-assessment module.

PubMed

Chew, Felix S; Bui-Mansfield, Liem T

2007-09-01

The educational objectives of this self-assessment module on imaging popliteal artery disease in young adults with intermittent claudication are for the participant to exercise, self-assess, and improve his or her knowledge of the imaging and clinical features of popliteal artery entrapment syndrome, cystic adventitial disease,and masses associated with popliteal artery obstruction.

The accuracy of assessment of walking distance in the elective spinal outpatients setting.

PubMed

Okoro, Tosan; Qureshi, Assad; Sell, Beulah; Sell, Philip

2010-02-01

Self reported walking distance is a clinically relevant measure of function. The aim of this study was to define patient accuracy and understand factors that might influence perceived walking distance in an elective spinal outpatients setting. A prospective cohort study. 103 patients were asked to perform one test of distance estimation and 2 tests of functional distance perception using pre-measured landmarks. Standard spine specific outcomes included the patient reported claudication distance, Oswestry disability index (ODI), Low Back Outcome Score (LBOS), visual analogue score (VAS) for leg and back, and other measures. There are over-estimators and under-estimators. Overall, the accuracy to within 9.14 metres (m) (10 yards) was poor at only 5% for distance estimation and 40% for the two tests of functional distance perception. Distance: Actual distance 111 m; mean response 245 m (95% CI 176.3-314.7), Functional test 1 actual distance 29.2 m; mean response 71.7 m (95% CI 53.6-88.9) Functional test 2 actual distance 19.6 m; mean response 47.4 m (95% CI 35.02-59.95). Surprisingly patients over 60 years of age (n = 43) are twice as accurate with each test performed compared to those under 60 (n = 60) (average 70% overestimation compared to 140%; p = 0.06). Patients in social class I (n = 18) were more accurate than those in classes II-V (n = 85): There was a positive correlation between poor accuracy and increasing MZD (Pearson's correlation coefficient 0.250; p = 0.012). ODI, LBOS and other parameters measured showed no correlation. Subjective distance perception and estimation is poor in this population. Patients over 60 and those with a professional background are more accurate but still poor.

Absolute Distances to Nearby Type Ia Supernovae via Light Curve Fitting Methods

NASA Astrophysics Data System (ADS)

Vinkó, J.; Ordasi, A.; Szalai, T.; Sárneczky, K.; Bányai, E.; Bíró, I. B.; Borkovits, T.; Hegedüs, T.; Hodosán, G.; Kelemen, J.; Klagyivik, P.; Kriskovics, L.; Kun, E.; Marion, G. H.; Marschalkó, G.; Molnár, L.; Nagy, A. P.; Pál, A.; Silverman, J. M.; Szakáts, R.; Szegedi-Elek, E.; Székely, P.; Szing, A.; Vida, K.; Wheeler, J. C.

2018-06-01

We present a comparative study of absolute distances to a sample of very nearby, bright Type Ia supernovae (SNe) derived from high cadence, high signal-to-noise, multi-band photometric data. Our sample consists of four SNe: 2012cg, 2012ht, 2013dy and 2014J. We present new homogeneous, high-cadence photometric data in Johnson–Cousins BVRI and Sloan g‧r‧i‧z‧ bands taken from two sites (Piszkesteto and Baja, Hungary), and the light curves are analyzed with publicly available light curve fitters (MLCS2k2, SNooPy2 and SALT2.4). When comparing the best-fit parameters provided by the different codes, it is found that the distance moduli of moderately reddened SNe Ia agree within ≲0.2 mag, and the agreement is even better (≲0.1 mag) for the highest signal-to-noise BVRI data. For the highly reddened SN 2014J the dispersion of the inferred distance moduli is slightly higher. These SN-based distances are in good agreement with the Cepheid distances to their host galaxies. We conclude that the current state-of-the-art light curve fitters for Type Ia SNe can provide consistent absolute distance moduli having less than ∼0.1–0.2 mag uncertainty for nearby SNe. Still, there is room for future improvements to reach the desired ∼0.05 mag accuracy in the absolute distance modulus.

Calculating Galactic Distances Through Supernova Light Curve Analysis (Abstract)

NASA Astrophysics Data System (ADS)

Glanzer, J.

2018-06-01

(Abstract only) The purpose of this project is to experimentally determine the distance to the galaxy M101 by using data that were taken on the type Ia supernova SN 2011fe at the Paul P. Feder Observatory. Type Ia supernovae are useful for determining distances in astronomy because they all have roughly the same luminosity at the peak of their outburst. Comparing the apparent magnitude to the absolute magnitude allows a measurement of the distance. The absolute magnitude is estimated in two ways: using an empirical relationship from the literature between the rate of decline and the absolute magnitude, and using sncosmo, a PYTHON package used for supernova light curve analysis that fits model light curves to the photometric data.

Effects of 12-week supervised treadmill training on spatio-temporal gait parameters in patients with claudication.

PubMed

Konik, Anita; Kuklewicz, Stanisław; Rosłoniec, Ewelina; Zając, Marcin; Spannbauer, Anna; Nowobilski, Roman; Mika, Piotr

2016-01-01

The purpose of the study was to evaluate selected temporal and spatial gait parameters in patients with intermittent claudication after completion of 12-week supervised treadmill walking training. The study included 36 patients (26 males and 10 females) aged: mean 64 (SD 7.7) with intermittent claudication. All patients were tested on treadmill (Gait Trainer, Biodex). Before the programme and after its completion, the following gait biomechanical parameters were tested: step length (cm), step cycle (cycle/s), leg support time (%), coefficient of step variation (%) as well as pain-free walking time (PFWT) and maximal walking time (MWT) were measured. Training was conducted in accordance with the current TASC II guidelines. After 12 weeks of training, patients showed significant change in gait biomechanics consisting in decreased frequency of step cycle (p < 0.05) and extended step length (p < 0.05). PFWT increased by 96% (p < 0.05). MWT increased by 100% (p < 0.05). After completing the training, patients' gait was more regular, which was expressed via statistically significant decrease of coefficient of variation (p < 0.05) for both legs. No statistically significant relation between the post-training improvement of PFWT and MWT and step length increase and decreased frequency of step cycle was observed (p > 0.05). Twelve-week treadmill walking training programme may lead to significant improvement of temporal and spatial gait parameters in patients with intermittent claudication. Twelve-week treadmill walking training programme may lead to significant improvement of pain-free walking time and maximum walking time in patients with intermittent claudication.

A new method for measuring oxidative stress in claudicants during strenuous exercise using free radical derivatives of antipyrine as indicators: a pilot study.

PubMed

Coolen, Stefan A J; Wijnen, Marc H W A; Reijenga, Jetse C; Vader, Huib L; Roumen, Rudi M H; Huf, Fred A

2002-01-01

Patients with intermittent claudication disease suffer from temporary lack of oxygen in the legs, caused by narrowing of arteries, resulting in ischemia and followed by reperfusion. The degree of oxidative stress present in 16 patients during strenuous exercise was determined using several indicators. Two derivatives of an exogenous marker, antipyrine (AP), (ie, p-hydroxyantipyrine, p-APOH, and o-hydroxyantipyrine, o-APOH), were assayed in plasma using HPLC-tandem-MS. Plasma malondialdehyde (assayed as thiobarbituric acid reactive species, TBARS) was also determined. The branchial/ankle blood pressure index (b-a index) was used to assess the severity of intermittent claudication disease, and plasma lactate concentration was also measured as an indicator of the ischemic situation. Plasma TBARS level did not change significantly after exercise. During the ischemic situation as well as during reperfusion, both free radical derivatives of antipyrine increased significantly in plasma (p < 0.01). Because p-APOH is also formed enzymatically in humans, the plasma ratio of o-APOH to AP appeared to be the most specific marker for oxidative stress in patients with intermittent claudication.

Successful percutaneous treatment of gluteal claudication secondary to isolated bilateral hypogastric stenoses.

PubMed

Chaer, Rabih A; Faries, Peter L; Lin, Stephanie; Dayal, Rajeev; McKinsey, James F; Kent, K Craig

2006-01-01

We report an unusual case of bilateral buttock claudication at ambulation of less than two blocks in a 57-year-old man with normal lower-extremity segmental pressure on noninvasive exercise testing. He was found to have bilateral high-grade internal iliac artery stenoses on arteriography. Both sides were successfully treated in a staged fashion via a contralateral approach with percutaneous transluminal angioplasty and a balloon-expandable stent, with complete symptom resolution. A clinical vascular examination with normal findings of the common iliac, external iliac, and common and superficial femoral arteries eliminates significant vascular obstruction as a cause of claudication. However, internal iliac occlusive disease may be suspected when symptoms are limited to the gluteal musculature and other causes are eliminated. Percutaneous interventions can be of diagnostic and therapeutic value.

Independent coding of absolute duration and distance magnitudes in the prefrontal cortex

PubMed Central

Marcos, Encarni; Tsujimoto, Satoshi

2016-01-01

The estimation of space and time can interfere with each other, and neuroimaging studies have shown overlapping activation in the parietal and prefrontal cortical areas. We used duration and distance discrimination tasks to determine whether space and time share resources in prefrontal cortex (PF) neurons. Monkeys were required to report which of two stimuli, a red circle or blue square, presented sequentially, were longer and farther, respectively, in the duration and distance tasks. In a previous study, we showed that relative duration and distance are coded by different populations of neurons and that the only common representation is related to goal coding. Here, we examined the coding of absolute duration and distance. Our results support a model of independent coding of absolute duration and distance metrics by demonstrating that not only relative magnitude but also absolute magnitude are independently coded in the PF. NEW & NOTEWORTHY Human behavioral studies have shown that spatial and duration judgments can interfere with each other. We investigated the neural representation of such magnitudes in the prefrontal cortex. We found that the two magnitudes are independently coded by prefrontal neurons. We suggest that the interference among magnitude judgments might depend on the goal rather than the perceptual resource sharing. PMID:27760814

Improved Walking Claudication Distance with Transcutaneous Electrical Nerve Stimulation: An Old Treatment with a New Indication in Patients with Peripheral Artery Disease.

PubMed

Labrunée, Marc; Boned, Anne; Granger, Richard; Bousquet, Marc; Jordan, Christian; Richard, Lisa; Garrigues, Damien; Gremeaux, Vincent; Sénard, Jean-Michel; Pathak, Atul; Guiraud, Thibaut

2015-11-01

The aim of this study was to determine whether 45 mins of transcutaneous electrical nerve stimulation before exercise could delay pain onset and increase walking distance in peripheral artery disease patients. After a baseline assessment of the walking velocity that led to pain after 300 m, 15 peripheral artery disease patients underwent four exercise sessions in a random order. The patients had a 45-min transcutaneous electrical nerve stimulation session with different experimental conditions: 80 Hz, 10 Hz, sham (presence of electrodes without stimulation), or control with no electrodes, immediately followed by five walking bouts on a treadmill until pain occurred. The patients were allowed to rest for 10 mins between each bout and had no feedback concerning the walking distance achieved. Total walking distance was significantly different between T10, T80, sham, and control (P < 0.0003). No difference was observed between T10 and T80, but T10 was different from sham and control. Sham, T10, and T80 were all different from control (P < 0.001). There was no difference between each condition for heart rate and blood pressure. Transcutaneous electrical nerve stimulation immediately before walking can delay pain onset and increase walking distance in patients with class II peripheral artery disease, with transcutaneous electrical nerve stimulation of 10 Hz being the most effective.

Stent-induced flow disturbances in the ipsilateral external carotid artery following internal carotid artery stenting: a temporary cause of jaw claudication.

PubMed

Giurgea, Georgiana-Aura; Haumer, Markus; Mlekusch, Irene; Sabeti-Sandor, Schila; Dick, Petra; Schillinger, Martin; Minar, Erich; Mlekusch, Wolfgang

2017-07-01

We hypothesize that stenting of the internal carotid artery can immediately impede blood flow to the external carotid artery by either plaque shift or stent coverage of the ostium, and thereby cause ischemic symptoms like ipsilateral jaw claudication. Thirty-three patients with high-grade asymptomatic stenosis of the internal carotid artery who underwent endovascular treatment were examined by ultrasound of the external carotid artery and performed an exercise test by chewing chewing gum synchronously to an electronic metronome for 3 min. Tests were performed before, the day after, and 1 week after the stenting procedure. Claudication time was defined as the timespan until occurrence of pain of the masseter muscle and/or chewing dyssynchrony to the metronome for more than 15 s. Ten patients with an isolated, atherosclerotic stenosis of the external carotid artery served as controls. A significantly reduced claudication time (in seconds) was recorded in patients who underwent carotid artery stenting compared to baseline values; median 89 (interquartile range, IQR, 57 to 124) vs. median 180 (IQR 153 to 180; p < 0.001). By categorization of the flow velocity at the external carotid artery into faster or slower as 200 cm/sec, the effect was even accentuated. Stenting values showed improvement 1 week after but did not return to baseline levels. No respective changes were found in controls. Stenting of the internal carotid artery lead to ipsilateral flow deterioration at the external carotid artery resulting in temporary jaw claudication. This impairment attenuated over the time and was significantly reduced after 1 week.

Cost-effectiveness of supervised exercise therapy compared with endovascular revascularization for intermittent claudication.

PubMed

van den Houten, M M L; Lauret, G J; Fakhry, F; Fokkenrood, H J P; van Asselt, A D I; Hunink, M G M; Teijink, J A W

2016-11-01

Current guidelines recommend supervised exercise therapy (SET) as the preferred initial treatment for patients with intermittent claudication. The availability of SET programmes is, however, limited and such programmes are often not reimbursed. Evidence for the long-term cost-effectiveness of SET compared with endovascular revascularization (ER) as primary treatment for intermittent claudication might aid widespread adoption in clinical practice. A Markov model was constructed to determine the incremental costs, incremental quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratio of SET versus ER for a hypothetical cohort of patients with newly diagnosed intermittent claudication, from the Dutch healthcare payer's perspective. In the event of primary treatment failure, possible secondary interventions were repeat ER, open revascularization or major amputation. Data sources for model parameters included original data from two RCTs, as well as evidence from the medical literature. The robustness of the results was tested with probabilistic and one-way sensitivity analysis. Considering a 5-year time horizon, probabilistic sensitivity analysis revealed that SET was associated with cost savings compared with ER (-€6412, 95 per cent credibility interval (CrI) -€11 874 to -€1939). The mean difference in effectiveness was -0·07 (95 per cent CrI -0·27 to 0·16) QALYs. ER was associated with an additional €91 600 per QALY gained compared with SET. One-way sensitivity analysis indicated more favourable cost-effectiveness for ER in subsets of patients with low quality-of-life scores at baseline. SET is a more cost-effective primary treatment for intermittent claudication than ER. These results support implementation of supervised exercise programmes in clinical practice. © 2016 BJS Society Ltd Published by John Wiley & Sons Ltd.

A Comparison of Clinical Outcomes for Diabetic and Nondiabetic Patients Following Directional Atherectomy in the DEFINITIVE LE Claudicant Cohort.

PubMed

Garcia, Lawrence A; Jaff, Michael R; Rocha-Singh, Krishna J; Zeller, Thomas; Bosarge, Christopher; Kamat, Suraj; McKinsey, James F

2015-10-01

To report a subset analysis that evaluated the hypothesis that directional atherectomy for peripheral artery disease in diabetic claudicants has noninferior primary patency at 12 months compared with nondiabetic claudicants. DEFINITIVE LE, a US/European multicenter study, assessed the effectiveness of directional atherectomy using SilverHawk/TurboHawk systems for treatment of peripheral artery disease in the superficial femoral, popliteal, and infrapopliteal arteries. Of the 800 patients enrolled in the study, only the 598 claudicant patients (mean age 69.5±10.4 years; 336 men) who were classified at baseline as Rutherford category 1-3 were eligible for this subset analysis. Of these, 46.8% (280/598) had diabetes. Follow-up to 12 months included duplex ultrasound examination, functional assessments, and adverse event evaluations. Independent angiographic and duplex ultrasound core laboratories assessed primary patency and secondary endpoints; a clinical events committee adjudicated adverse events. Although diabetics had significantly more baseline comorbidities, 12-month primary patency (77.0%) was no different than for nondiabetics (77.9%; superiority p=0.98; noninferiority p<0.001) across all anatomic territories treated. Freedom from clinically driven target lesion revascularization was no different between diabetics (83.8%) and nondiabetics (87.5%) overall (p=0.19) or by lesion locations. Secondary clinical outcomes (Rutherford category, ankle-brachial index, and walking impairment) improved at 12 months for both diabetics and nondiabetics. Noninferior 12-month patency rates demonstrate that directional atherectomy is an effective treatment in diabetic as well as nondiabetic claudicants. Directional atherectomy remains an attractive treatment option, improving luminal diameters without stents, which preserves future treatment options for both diabetic and nondiabetic patients with progressive, diffuse vascular disease. © The Author(s) 2015.

The efficacy of transcutaneous electrical nerve stimulation on the improvement of walking distance in patients with peripheral arterial disease with intermittent claudication: study protocol for a randomised controlled trial: the TENS-PAD study.

PubMed

Besnier, Florent; Sénard, Jean-Michel; Grémeaux, Vincent; Riédel, Mélanie; Garrigues, Damien; Guiraud, Thibaut; Labrunée, Marc

2017-08-10

In patients with peripheral arterial disease (PAD), walking improvements are often limited by early pain onset due to vascular claudication. It would thus appear interesting to develop noninvasive therapeutic strategies, such as transcutaneous electrical nerve stimulation (TENS), to improve the participation of PAD patients in rehabilitation programmes, and thus improve their quality of life. Our team recently tested the efficacy of a single 45-min session of 10-Hz TENS prior to walking. TENS significantly delayed pain onset and increased the pain-free walking distance in patients with class-II PAD. We now seek to assess the efficacy of a chronic intervention that includes the daily use of TENS for 3 weeks (5 days a week) on walking distance in Leriche-Fontaine stage-II PAD patients. This is a prospective, double-blind, multicentre, randomised, placebo-controlled trial. One hundred subjects with unilateral PAD (Leriche-Fontaine stage II) will be randomised into two groups (1:1). For the experimental group (TENS group): the treatment will consist of stimulation of the affected leg (at a biphasic frequency of 10 Hz, with a pulse width of 200 μs, maximal intensity below the motor threshold) for 45 min per day, in the morning before the exercise rehabilitation programme, for 3 weeks, 5 days per week. For the control group (SHAM group): the placebo stimulation will be delivered according to the same modalities as for the TENS group but with a voltage level automatically falling to zero after 10 s of stimulation. First outcome: walking distance without pain. transcutaneous oxygen pressure (TcPO 2 ) measured during a Strandness exercise test, peak oxygen uptake (VO 2 peak), endothelial function (EndoPAT®), Ankle-brachial Pressure Index, Body Mass Index, lipid profile (LDL-C, HDL-C, triglycerides), fasting glycaemia, HbA1c level, and the WELCH questionnaire. TENS-PAD is the first randomised controlled trial that uses transcutaneous electrical therapy as an adjuvant technique to improve vascular function in the treatment of PAD. If the results are confirmed, this technique could be incorporated into the routine care in cardiovascular rehabilitation centers and used in the long term by patients to improve their walking capacity. ClinicalTrials.gov, ID: NCT02678403 . Registered on 9 February 2016. Toulouse University Hospital.

A distance-independent calibration of the luminosity of type Ia supernovae and the Hubble constant

NASA Technical Reports Server (NTRS)

Leibundgut, Bruno; Pinto, Philip A.

1992-01-01

The absolute magnitude of SNe Ia at maximum is calibrated here using radioactive decay models for the light curve and a minimum of assumptions. The absolute magnitude parameter space is studied using explosion models and a range of rise times, and absolute B magnitudes at maximum are used to derive a range of the H0 and the distance to the Virgo Cluster from SNe Ia. Rigorous limits for H0 of 45 and 105 km/s/Mpc are derived.

One-Year Outcomes Following Directional Atherectomy of Popliteal Artery Lesions: Subgroup Analysis of the Prospective, Multicenter DEFINITIVE LE Trial

PubMed Central

Rastan, Aljoscha; McKinsey, James F.; Garcia, Lawrence A.; Rocha-Singh, Krishna J.; Jaff, Michael R.; Harlin, Stuart; Kamat, Suraj; Janzer, Sean; Zeller, Thomas

2017-01-01

Purpose: To report the effectiveness of directional atherectomy for the treatment of popliteal artery occlusive disease. Methods: This subset of the prospective, multicenter, single-arm DEFINITIVE LE trial included 158 patients (mean age 72.0±10.9 years; 82 men) who underwent directional atherectomy in 162 popliteal artery lesions between 2009 and 2011. Forty-eight (30.4%) patients were suffering from critical limb ischemia (CLI). The mean lesion length was 5.8±3.9 cm; 38 (23.5%) arteries were occluded. The primary outcome measure for patients with intermittent claudication (IC) was duplex ultrasound–defined primary patency at 1 year; the outcome for subjects with CLI was freedom from major amputation of the target limb at 1 year. Outcomes and adverse events were independently assessed. Results: Procedure success (≤30% residual stenosis) was achieved in 84.4% of treated lesions; adjunctive stenting was required in 6 (3.7%) of the 162 lesions. The 1-year primary patency rate was 75.0% (IC patients 78.2% and CLI patients 67.5%, p=0.118). The freedom from major amputation in both cohorts was 100%. In both IC and CLI patients, significant improvements were demonstrated at 1 year in the Rutherford category, walking distance, and quality of life in comparison to baseline. Conclusion: This study indicates that directional atherectomy in popliteal arteries leads to favorable technical and clinical results at 1 year for claudicant as well as CLI patients. PMID:29117818

One-Year Outcomes Following Directional Atherectomy of Popliteal Artery Lesions: Subgroup Analysis of the Prospective, Multicenter DEFINITIVE LE Trial.

PubMed

Rastan, Aljoscha; McKinsey, James F; Garcia, Lawrence A; Rocha-Singh, Krishna J; Jaff, Michael R; Harlin, Stuart; Kamat, Suraj; Janzer, Sean; Zeller, Thomas

2018-02-01

To report the effectiveness of directional atherectomy for the treatment of popliteal artery occlusive disease. This subset of the prospective, multicenter, single-arm DEFINITIVE LE trial included 158 patients (mean age 72.0±10.9 years; 82 men) who underwent directional atherectomy in 162 popliteal artery lesions between 2009 and 2011. Forty-eight (30.4%) patients were suffering from critical limb ischemia (CLI). The mean lesion length was 5.8±3.9 cm; 38 (23.5%) arteries were occluded. The primary outcome measure for patients with intermittent claudication (IC) was duplex ultrasound-defined primary patency at 1 year; the outcome for subjects with CLI was freedom from major amputation of the target limb at 1 year. Outcomes and adverse events were independently assessed. Procedure success (≤30% residual stenosis) was achieved in 84.4% of treated lesions; adjunctive stenting was required in 6 (3.7%) of the 162 lesions. The 1-year primary patency rate was 75.0% (IC patients 78.2% and CLI patients 67.5%, p=0.118). The freedom from major amputation in both cohorts was 100%. In both IC and CLI patients, significant improvements were demonstrated at 1 year in the Rutherford category, walking distance, and quality of life in comparison to baseline. This study indicates that directional atherectomy in popliteal arteries leads to favorable technical and clinical results at 1 year for claudicant as well as CLI patients.

Supervised exercise therapy: it does work, but how to set up a program?

PubMed

Hageman, David; van den Houten, Marijn M; Spruijt, Steffie; Gommans, Lindy N; Scheltinga, Marc R; Teijink, Joep A

2017-04-01

Intermittent claudication (IC) is a manifestation of peripheral arterial disease. IC has a high prevalence in the older population, is closely associated with other expressions of atherosclerotic disease and often co-exists in multimorbid patients. Treatment of IC should address reduction of cardiovascular risk and improvement of functional capacity and health-related quality of life (QoL). As recommended by contemporary international guidelines, the first-line treatment includes supervised exercise therapy (SET). In several randomized controlled trials and systematic reviews, SET is compared with usual care, placebo, walking advice and endovascular revascularization. The evidence supporting the efficacy of SET programs to alleviate claudication symptoms is robust. SET improves walking distance and health-related QoL and appears to be the most cost-effective treatment for IC. Nevertheless, only few of all newly diagnosed IC patients worldwide receive this safe, efficient and structured treatment. Worldwide implementation of structured SET programs is seriously impeded by outdated arguments favoring an invasive intervention, absence of a network of specialized physical therapists providing standardized SET and lack of awareness and/or knowledge of the importance of SET by referring physicians. Besides, misguiding financial incentives and lack of reimbursement hamper actual use of SET programs. In the Netherlands, a national integrated care network (ClaudicatioNet) was launched in 2011 to combat treatment shortcomings and stimulate cohesion and collaboration between stakeholders. This care intervention has resulted in optimized quality of care for all patients with IC.

Absolute distance measurement with correction of air refractive index by using two-color dispersive interferometry.

PubMed

Wu, Hanzhong; Zhang, Fumin; Liu, Tingyang; Li, Jianshuang; Qu, Xinghua

2016-10-17

Two-color interferometry is powerful for the correction of the air refractive index especially in the turbulent air over long distance, since the empirical equations could introduce considerable measurement uncertainty if the environmental parameters cannot be measured with sufficient precision. In this paper, we demonstrate a method for absolute distance measurement with high-accuracy correction of air refractive index using two-color dispersive interferometry. The distances corresponding to the two wavelengths can be measured via the spectrograms captured by a CCD camera pair in real time. In the long-term experiment of the correction of air refractive index, the experimental results show a standard deviation of 3.3 × 10^-8 for 12-h continuous measurement without the precise knowledge of the environmental conditions, while the variation of the air refractive index is about 2 × 10^-6. In the case of absolute distance measurement, the comparison with the fringe counting interferometer shows an agreement within 2.5 μm in 12 m range.

Primary Stenting of the Superficial Femoral Artery in Patients with Intermittent Claudication Has Durable Effects on Health-Related Quality of Life at 24 Months: Results of a Randomized Controlled Trial.

PubMed

Lindgren, Hans I V; Qvarfordt, Peter; Bergman, Stefan; Gottsäter, Anders

2018-06-01

Intermittent claudication (IC) is commonly caused by lesions in the superficial femoral artery (SFA), yet invasive treatment is still controversial and longer term patient-reported outcomes are lacking. This prospective randomized trial assessed the 24-month impact of primary stenting with nitinol self-expanding stents compared to best medical treatment (BMT) alone in patients with stable IC due to SFA disease on health-related quality of life (HRQoL). One hundred patients with stable IC due to SFA disease treated with BMT were randomized to either stent (n = 48) or control (n = 52) group. HRQoL assessed by Short Form 36 Health Survey (SF-36) and EuroQoL 5-dimensions (EQ5D) 24 months after treatment were primary outcome measures. Walking Impairment Questionnaire, ankle-brachial index (ABI), and walking distance were secondary outcomes. Significantly better SF-36 Physical Component Summary (P = 0.024) and physical domain scores such as Physical Function (P = 0.012), Bodily Pain (P = 0.002), General Health (P = 0.037), and EQ5D (P = 0.010) were reported in intergroup comparison between the stent and the control group. Both ABI (from 0.58 ± 0.11 to 0.85 ± 0.18; P < 0.001 in the stent group and from 0.63 ± 0.17 to 0.69 ± 0.18; P = 0.036 in the control group) and walking distance (from 170 ± 90 m to 616 ± 375 m; P < 0.001 in the stent group and from 209 ± 111 m to 331 ± 304 m; P = 0.006 in the control group) improved significantly in intragroup comparisons. In patients with IC caused by lesions in the SFA, primary stenting compared to BMT alone was associated with significant improvements in HRQoL, ABI, and walking distance durable up to 24 months of follow-up. Clinical Trial Registration http://www.clinicaltrials.gov . Unique Identifier: NCT01230229.

Improved performance of semiconductor laser tracking frequency gauge

NASA Astrophysics Data System (ADS)

Kaplan, D. M.; Roberts, T. J.; Phillips, J. D.; Reasenberg, R. D.

2018-03-01

We describe new results from the semiconductor-laser tracking frequency gauge, an instrument that can perform sub-picometer distance measurements and has applications in gravity research and in space-based astronomical instruments proposed for the study of light from extrasolar planets. Compared with previous results, we have improved incremental distance accuracy by a factor of two, to 0.9 pm in 80 s averaging time, and absolute distance accuracy by a factor of 20, to 0.17 μm in 1000 s. After an interruption of operation of a tracking frequency gauge used to control a distance, it is now possible, using a nonresonant measurement interferometer, to restore the distance to picometer accuracy by combining absolute and incremental distance measurements.

A Primary Care Approach to the Diagnosis and Management of Peripheral Arterial Disease

NASA Technical Reports Server (NTRS)

Dawson, David L.

2000-01-01

The objectives of this work are: (1) Be able to recognize characteristic symptoms of intermittent claudication (2) Diagnose PAD on the basis of history, physical exam, and simple limb blood pressure measurements (3) Recognize the significance of peripheral artery disease as a marker for coronary or cerebrovascular atherosclerosis (4) Provide appropriate medical management of atherosclerosis risk factors-- including use of antiplatelet therapy to reduce risk of myocardial infarction, stroke and death (5) Manage symptoms of intermittent claudication with program of smoking cessation, exercise, and medication The diagnosis of intermittent claudication secondary to peripheral artery disease (PAD) can often be made on the basis of history and physical examination. Additional evaluation of PAD is multi-modal and the techniques used will vary depending on the nature and severity of the patient's presenting problem. Most patients can be appropriately managed without referral for specialized diagnostic services or interventions.

Absolute distance measurement by dual-comb interferometry with multi-channel digital lock-in phase detection

NASA Astrophysics Data System (ADS)

Yang, Ruitao; Pollinger, Florian; Meiners-Hagen, Karl; Krystek, Michael; Tan, Jiubin; Bosse, Harald

2015-08-01

We present a dual-comb-based heterodyne multi-wavelength absolute interferometer capable of long distance measurements. The phase information of the various comb modes is extracted in parallel by a multi-channel digital lock-in phase detection scheme. Several synthetic wavelengths of the same order are constructed and the corresponding phases are averaged to deduce the absolute lengths with significantly reduced uncertainty. Comparison experiments with an incremental HeNe reference interferometer show a combined relative measurement uncertainty of 5.3 × 10-7 at a measurement distance of 20 m. Combining the advantage of synthetic wavelength interferometry and dual-comb interferometry, our compact and simple approach provides sufficient precision for many industrial applications.

A novel multi-dimensional absolute distance measurement system using a basic frequency modulated continuous wave radar and an external cavity laser with trilateration metrology

NASA Astrophysics Data System (ADS)

Xiong, Xingting; Qu, Xinghua; Zhang, Fumin

2018-01-01

We propose and describe a novel multi-dimensional absolute distance measurement system. This system incorporates a basic frequency modulated continuous wave (FMCW) radar and an second external cavity laser (ECL). Through the use of trilateration, the system in our paper can provide 3D resolution inherently range. However, the measured optical path length differences (OPD) is often variable in industrial environments and this will causes Doppler effect, which has greatly impact on the measurement result. With using the second ECL, the system can correct the Doppler effect to ensure the precision of absolute distance measurement. Result of the simulation will prove the influence of Doppler effect.

ASTRONOMY: The Distance to the Large Magellanic Cloud.

PubMed

Cole, A A

2000-08-18

The Large Magellanic Cloud (LMC), a satellite of the Milky Way, is an important yardstick by which most intergalactic distances are measured. But as Cole explains in this Perspective, how far away the LMC is remains a matter of dispute, with far reaching implications in cosmology. But observations of Cepheids and of eclipsing binaries, two types of stars that allow absolute luminosity and thus absolute distances to be determined, are promising to resolve this important issue in the not too distant future.

Quantitative endoscopy: initial accuracy measurements.

PubMed

Truitt, T O; Adelman, R A; Kelly, D H; Willging, J P

2000-02-01

The geometric optics of an endoscope can be used to determine the absolute size of an object in an endoscopic field without knowing the actual distance from the object. This study explores the accuracy of a technique that estimates absolute object size from endoscopic images. Quantitative endoscopy involves calibrating a rigid endoscope to produce size estimates from 2 images taken with a known traveled distance between the images. The heights of 12 samples, ranging in size from 0.78 to 11.80 mm, were estimated with this calibrated endoscope. Backup distances of 5 mm and 10 mm were used for comparison. The mean percent error for all estimated measurements when compared with the actual object sizes was 1.12%. The mean errors for 5-mm and 10-mm backup distances were 0.76% and 1.65%, respectively. The mean errors for objects <2 mm and > or =2 mm were 0.94% and 1.18%, respectively. Quantitative endoscopy estimates endoscopic image size to within 5% of the actual object size. This method remains promising for quantitatively evaluating object size from endoscopic images. It does not require knowledge of the absolute distance of the endoscope from the object, rather, only the distance traveled by the endoscope between images.

Gene therapy for therapeutic angiogenesis in peripheral arterial disease - a systematic review and meta-analysis of randomized, controlled trials.

PubMed

Hammer, Alexandra; Steiner, Sabine

2013-09-01

Beyond pharmacological, endovascular and surgical treatment strategies for peripheral arterial disease (PAD), therapeutic angiogenesis has been advocated to relieve symptoms and support limb salvage, in particular in patients with critical limb ischemia. We aimed to systematically review randomized controlled trials (RCTs) of gene therapy in PAD. A systematic search of electronic databases was performed to identify RCTs studying local administration of pro-angiogenic growth factors (VEGF, FGF, HGF, Del-1, HIF-1alpha) using plasmid or viral gene transfer by intra-arterial or intra-muscular injections. Outcomes of interest comprised all-cause mortality, amputations, ulcer healing, walking distance and ankle-brachial index. If feasible, standard meta-analysis should be performed with subgroup analysis for claudicants and patients with critical limb ischemia (CLI). The systematic search yielded 12 RCTs for analysis from 1163 citations. In total, 1494 patients (29 % females) were included with the majority suffering from CLI (64 %). Various endpoints were improved by single studies, but none by a majority of studies. Meta-analysis showed neither a significant benefit nor harm for gene therapy when synthesizing data for all-cause mortality (OR 0.88, 95 % CI 0.62 - 1.26) amputations (OR 0.64, 95 % CI 0.31 - 1.31) or ulcer healing (OR 1.79, 95 % CI 0.8 - 4.01). No differences were seen between patients with intermittent claudication or CLI. Despite promising results in single studies, no clear benefit could be identified for gene therapy in PAD patients, irrespective of disease severity.

Self-administered versus interview-based questionnaires among patients with intermittent claudication: Do they give different results? A cross-sectional study.

PubMed

Lozano, Francisco; Lobos, José María; March, José Ramón; Carrasco, Eduardo; Barros, Marcello Barbosa; González-Porras, José Ramón

2016-01-01

Many clinical investigations use generic and/or specific questionnaires to obtain information about participants and patients. There is disagreement about whether the administration method can affect the results. The aim here was to determine whether, among patients with intermittent claudication (IC), there are differences in the Walking Impairment Questionnaire (WIQ) and European Quality of Life-5 Dimension (EQ-5D) scores with regard to: 1) the questionnaire administration method (self-administration versus face-to-face interview); and 2) the type of interviewer (vascular surgeon, VS, versus general practitioner, GP). Cross-sectional observational multicenter epidemiological study carried out within the Spanish National Health Service. 1,641 evaluable patients with IC firstly completed the WIQ and EQ-5D questionnaires and then were interviewed by their doctor on the same day. Pearson correlations and Chi-square tests were used. There was a strong correlation (r > 0.800; P < 0.001) between the two methods of administering the WIQ and EQ-5D questionnaires, and between the VS and GP groups. Likewise, there was a high level of concordance (P > 0.05) between the different dimensions of the WIQ-distance and EQ-5D (self-administration versus face-to-face) in the VS and GP groups. There was no difference between the different methods of administering the WIQ and EQ-5D questionnaires, among the patients with IC. Similarly, the two types of interviewers (VS or GP) were equally valid. Therefore, it seems unnecessary to expend effort to administer these questionnaires by interview, in studies on IC.

Special electronic distance meter calibration for precise engineering surveying industrial applications

NASA Astrophysics Data System (ADS)

Braun, Jaroslav; Štroner, Martin; Urban, Rudolf

2015-05-01

All surveying instruments and their measurements suffer from some errors. To refine the measurement results, it is necessary to use procedures restricting influence of the instrument errors on the measured values or to implement numerical corrections. In precise engineering surveying industrial applications the accuracy of the distances usually realized on relatively short distance is a key parameter limiting the resulting accuracy of the determined values (coordinates, etc.). To determine the size of systematic and random errors of the measured distances were made test with the idea of the suppression of the random error by the averaging of the repeating measurement, and reducing systematic errors influence of by identifying their absolute size on the absolute baseline realized in geodetic laboratory at the Faculty of Civil Engineering CTU in Prague. The 16 concrete pillars with forced centerings were set up and the absolute distances between the points were determined with a standard deviation of 0.02 millimetre using a Leica Absolute Tracker AT401. For any distance measured by the calibrated instruments (up to the length of the testing baseline, i.e. 38.6 m) can now be determined the size of error correction of the distance meter in two ways: Firstly by the interpolation on the raw data, or secondly using correction function derived by previous FFT transformation usage. The quality of this calibration and correction procedure was tested on three instruments (Trimble S6 HP, Topcon GPT-7501, Trimble M3) experimentally using Leica Absolute Tracker AT401. By the correction procedure was the standard deviation of the measured distances reduced significantly to less than 0.6 mm. In case of Topcon GPT-7501 is the nominal standard deviation 2 mm, achieved (without corrections) 2.8 mm and after corrections 0.55 mm; in case of Trimble M3 is nominal standard deviation 3 mm, achieved (without corrections) 1.1 mm and after corrections 0.58 mm; and finally in case of Trimble S6 is nominal standard deviation 1 mm, achieved (without corrections) 1.2 mm and after corrections 0.51 mm. Proposed procedure of the calibration and correction is in our opinion very suitable for increasing of the accuracy of the electronic distance measurement and allows the use of the common surveying instrument to achieve uncommonly high precision.

Bilateral hypogastric artery occlusion in endovascular repair of abdominal aortic aneurysms and its clinical significance.

PubMed

Zander, Tobias; Baldi, Sebastian; Rabellino, Martin; Rostagno, Roman; Isaza, Baltasar; Llorens, Rafael; Carreira, Jose M; Maynar, Manuel

2007-12-01

Endovascular treatment of aortoiliac aneurysms near or involving the hypogastric artery (HGA) requires HGA occlusion before endografting to avoid retrograde filling of the aneurysm. The purpose of this study is to evaluate clinical outcomes of bilateral HGA occlusion and determine if benefits gained by endovascular aneurysm repair (EVAR) outweigh the morbidity associated with the procedure. Between 1999 and 2004, 128 patients with abdominal aortic aneurysm (AAA) were treated with bifurcated endograft placement. Bilateral coverage or embolization of HGAs was performed in 14 patients (10.9%). Embolization was achieved by deployment of coils and coverage was accomplished by extending the endoprosthesis into the external iliac artery. Clinical follow-up and computed tomographic angiography were performed at 1, 3, 6, 9, and 12 months and annually thereafter to detect potential aneurysm growth and endoleaks. During follow-up (range, 1-72 months), buttock claudication was noted in four patients (28.6%), including unilateral claudication in two and bilateral claudication in two. One patient experienced claudication longer than 12 months, which resolved within 18 months. De novo erectile dysfunction was seen in one patient, and pelvic ischemia was not found in any patient. There was no evidence of endoleak, aneurysm enlargement, or death associated with HGA occlusion. In our series, complications of bilateral HGA occlusion before EVAR were moderate and resolved over time. The benefits gained from EVAR outweigh the clinical problems caused by bilateral HGA occlusion, as there are no technical complications added to the EVAR procedure.

Design considerations and validation of the MSTAR absolute metrology system

NASA Astrophysics Data System (ADS)

Peters, Robert D.; Lay, Oliver P.; Dubovitsky, Serge; Burger, Johan; Jeganathan, Muthu

2004-08-01

Absolute metrology measures the actual distance between two optical fiducials. A number of methods have been employed, including pulsed time-of-flight, intensity-modulated optical beam, and two-color interferometry. The rms accuracy is currently limited to ~5 microns. Resolving the integer number of wavelengths requires a 1-sigma range accuracy of ~0.1 microns. Closing this gap has a large pay-off: the range (length measurement) accuracy can be increased substantially using the unambiguous optical phase. The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. In this paper, we present recent experiments that use dispersed white light interferometry to independently validate the zero-point of the system. We also describe progress towards reducing the size of optics, and stabilizing the laser wavelength for operation over larger target ranges. MSTAR is a general-purpose tool for conveniently measuring length with much greater accuracy than was previously possible, and has a wide range of possible applications.

The absolute disparity anomaly and the mechanism of relative disparities.

PubMed

Chopin, Adrien; Levi, Dennis; Knill, David; Bavelier, Daphne

2016-06-01

There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's absolute disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different absolute and relative disparities. Participants were asked to judge the depth of two lines presented at the same distance from the fixation plane (absolute disparity) or the depth between two lines presented at different distances (relative disparity). We used a single stimulus method involving a unique memory component for both conditions, and no extraneous references were available. We also measured vergence noise using Nonius lines. Stereo thresholds were substantially worse for absolute disparities than for relative disparities, and the difference could not be explained by vergence noise. We attribute this difference to an absence of conscious readout of absolute disparities, termed the absolute disparity anomaly. We further show that the pattern of correlations between vergence noise and absolute and relative disparity acuities can be explained jointly by the existence of the absolute disparity anomaly and by the assumption that relative disparity information is computed from absolute disparities (Hypothesis 1).

The absolute disparity anomaly and the mechanism of relative disparities

PubMed Central

Chopin, Adrien; Levi, Dennis; Knill, David; Bavelier, Daphne

2016-01-01

There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's absolute disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different absolute and relative disparities. Participants were asked to judge the depth of two lines presented at the same distance from the fixation plane (absolute disparity) or the depth between two lines presented at different distances (relative disparity). We used a single stimulus method involving a unique memory component for both conditions, and no extraneous references were available. We also measured vergence noise using Nonius lines. Stereo thresholds were substantially worse for absolute disparities than for relative disparities, and the difference could not be explained by vergence noise. We attribute this difference to an absence of conscious readout of absolute disparities, termed the absolute disparity anomaly. We further show that the pattern of correlations between vergence noise and absolute and relative disparity acuities can be explained jointly by the existence of the absolute disparity anomaly and by the assumption that relative disparity information is computed from absolute disparities (Hypothesis 1). PMID:27248566

Ordinary Least Squares and Quantile Regression: An Inquiry-Based Learning Approach to a Comparison of Regression Methods

ERIC Educational Resources Information Center

Helmreich, James E.; Krog, K. Peter

2018-01-01

We present a short, inquiry-based learning course on concepts and methods underlying ordinary least squares (OLS), least absolute deviation (LAD), and quantile regression (QR). Students investigate squared, absolute, and weighted absolute distance functions (metrics) as location measures. Using differential calculus and properties of convex…

Lower extremity revascularization using directional atherectomy: 12-month prospective results of the DEFINITIVE LE study.

PubMed

McKinsey, James F; Zeller, Thomas; Rocha-Singh, Krishna J; Jaff, Michael R; Garcia, Lawrence A

2014-08-01

The aim of this study was to assess the safety and effectiveness of directional atherectomy (DA) for endovascular treatment of peripheral arterial disease (PAD) in infrainguinal arteries in patients with claudication or critical limb ischemia. To date, no prospective, multicenter, independently-adjudicated study has evaluated the effectiveness and durability of DA in the treatment of PAD. Previous DA studies have not been prospectively powered to evaluate any differences in outcomes in patients with and without diabetes. DEFINITIVE LE (Determination of EFfectiveness of the SilverHawk(®) PerIpheral Plaque ExcisioN System (SIlverHawk Device) for the Treatment of Infrainguinal VEssels / Lower Extremities) prospectively enrolled subjects at 47 multinational centers with an infrainguinal lesion length up to 20 cm. Primary endpoints were defined as primary patency at 12 months for claudicants and freedom from major unplanned amputation for critical limb ischemia (CLI) subjects. A pre-specified statistical hypothesis evaluated noninferiority of primary patency in diabetic versus nondiabetic claudicants. Independent angiographic and sonographic core laboratories assessed outcomes, and events were adjudicated by a clinical events committee. A total of 800 subjects were enrolled. The 12-month primary patency was 78% (95% confidence interval: 74.0% to 80.6%) in claudicants, with a 77% rate in the diabetic subgroup versus 78% in the nondiabetic subgroup (noninferior, p < 0.001). The rate of freedom from major unplanned amputation of the target limb at 12 months in CLI subjects was 95% (95% confidence interval: 90.7% to 97.4%). Periprocedural adverse events included embolization (3.8%), perforation (5.3%), and abrupt closure (2.0%). The bail-out stent rate was 3.2%. The DEFINITIVE LE study demonstrated that DA is a safe and effective treatment modality at 12 months for a diverse patient population with either claudication or CLI. Furthermore, DA was shown to be noninferior for treating PAD in patients with diabetes compared with those without diabetes. (Study of SilverHawk/TurboHawk in Lower Extremity Vessels [DEFINITIVE LE]; NCT00883246). Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Lumbar spinous process splitting decompression provides equivalent outcomes to conventional midline decompression in degenerative lumbar canal stenosis: a prospective, randomized controlled study of 51 patients.

PubMed

Rajasekaran, S; Thomas, Ashok; Kanna, Rishi M; Prasad Shetty, Ajoy

2013-09-15

Prospective, randomized controlled study. To compare the functional outcomes and extent of paraspinal muscle damage between 2 decompressive techniques for lumbar canal stenosis. Lumbar spinous process splitting decompression (LSPSD) preserves the muscular and liga-mentous attachments of the posterior elements of the spine. It can potentially avoid problems such as paraspinal muscle atrophy and trunk extensor weakness that can occur after conventional midline decompression. However, large series prospective randomized controlled studies are lacking. Patients with lumbar canal stenosis were randomly allocated into 2 groups: LSPSD (28 patients) and conventional midline decompression (23 patients). The differences in operative time, blood loss, time to comfortable mobilization, and hospital stay were studied. Paraspinal muscle damage was assessed by postoperative rise in creatine phosphokinase and C-reactive protein levels. Functional outcome was evaluated at 1 year by Japanese Orthopaedic Association score, neurogenic claudication outcome score, and visual analogue scale for back pain and neurogenic claudication. Fifty-one patients of mean age 56 years were followed-up for a mean 14.2 ± 2.9 months. There were no significant differences in the operative time, blood loss, and hospital stay. Both the groups showed significant improvement in the functional outcome scores at 1 year. Between the 2 groups, the Japanese Orthopaedic Association score, neurogenic claudication outcome score improvement, visual analogue scale for back pain, neurogenic claudication visual analogue scale, and the postoperative changes in serum C-reactive protein and creatine phosphokinase levels did not show any statistically significant difference. On the basis of the Japanese Orthopaedic Association recovery rate, it was found that 73.9% of conventional midline decompression group had good outcomes compared with only 60.7% after LSPSD. The functional outcome scores, back pain, and claudication pain in the immediate period and at the end of 1 year are similar in both the techniques. More patients had better functional outcomes after conventional decompression than the LSPSD technique. On the basis of this study, the superiority of one technique compared with the other is not established, mandating the need for further long-term studies. 2.

Comparison of two progressive treadmill tests in patients with peripheral arterial disease.

PubMed

Riebe, D; Patterson, R B; Braun, C M

2001-11-01

In a vascular rehabilitation program, 28% of our frail elderly patients are unable to be tested with traditional progressive exercise protocols at program entry due to the high (2.0 miles/h or 3.2 km/h) initial treadmill speeds. The purpose of this investigation was to compare a new progressive treadmill protocol which has a reduced initial speed (1.0 mile/h or 1.6 km/h) to an established protocol performed at 2.0 miles/h (3.2 km/h) to determine the comparability and reproducibility of the new protocol. Eleven patients with arterial claudication performed three symptom-limited exercise tests in random order. Two tests used the new protocol while the remaining trial used the established protocol. Claudication pain was measured using a 5-point scale. Oxygen consumption, heart rate, minute ventilation, respiratory exchange ratio and blood pressure at peak exercise were similar among the three trials. There were strong intraclass correlations for peak oxygen consumption (r = 0.97), onset of claudication (r = 0.96) and maximum walking time (r = 0.98) between the two trials using the new protocol. There was also a significant correlation between the new protocol and the established protocol for peak oxygen consumption (r = 0.90) and maximum walking time (r = 0.89). The new progressive treadmill protocol represents a valid, reliable protocol for patients with arterial claudication. This protocol may be useful for testing patients with a low functional capacity so that clinically appropriate exercise prescriptions can be established and the efficacy of treatments can be determined.

Analysis of isokinetic muscle function and postural control in individuals with intermittent claudication

PubMed Central

Lanzarin, Morgan; Parizoto, Patricia; Santos, Gilmar M.

2016-01-01

BACKGROUND: Intermittent claudication (IC) is a debilitating condition that mostly affects elderly people. IC is manifested by a decrease in ambulatory function. Individuals with IC present with motor and sensory nerve dysfunction in the lower extremities, which may lead to deficits in balance. OBJECTIVE: This study aimed to measure postural control and isokinetic muscle function in individuals with intermittent claudication. METHOD: The study included 32 participants of both genders, 16 IC participants (mean age: 64 years, SD=6) and 16 healthy controls (mean age: 67 years, SD=5), which were allocated into two groups: intermittent claudication group (ICG) and control group (CG). Postural control was assessed using the displacement and velocity of the center of pressure (COP) during the sensory organization test (SOT) and the motor control test (MCT). Muscle function of the flexor and extensor muscles of the knee and ankle was measured by an isokinetic dynamometer. Independent t tests were used to calculate the between-group differences. RESULTS: The ICG presented greater displacement (p =0.027) and speed (p =0.033) of the COP in the anteroposterior direction (COPap) during the MCT, as well as longer latency (p =0.004). There were no between-group differences during the SOT. The ICG showed decreased muscle strength and power in the plantar flexors compared to the CG. CONCLUSION: Subjects with IC have lower values of strength and muscle power of plantiflexores, as well as changes in postural control in dynamic conditions. These individuals may be more vulnerable to falls than healthy subjects. PMID:26786077

The visual perception of size and distance.

DOT National Transportation Integrated Search

1962-07-01

The perception of absolute distance has been assumed to be important in the perception of the size of objects and the depth between them. A different hypothesis is proposed. It is asserted that perceived relative size and distance are the primary psy...

Astrometry With the Hubble Space Telescope: Trigonometric Parallaxes of Planetary Nebula Nuclei NGC 6853, NGC 7293, ABELL 31, and DeHt 5

NASA Technical Reports Server (NTRS)

Benedict, G. F.; McArthur, Barbara E.; Napiwotzki, Ralf; Harrison, Thomas E.; Harris, Hugh C.; Nelan, Edmund; Bond, Howard E; Patterson, Richard J.; Ciardullo, Robin

2009-01-01

We present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix), Abell 31, and DeHt 5. This paper details our reduction and analysis using DeHt 5 as an example. We obtain these planetary nebula nuclei (PNNi) parallaxes with astrometric data from Fine Guidance Sensors FGS 1r and FGS 3, white-light interferometers on the Hubble Space Telescope. Proper motions, spectral classifications and VJHKT2M and DDO51 photometry of the stars comprising the astrometric reference frames provide spectrophotometric estimates of reference star absolute parallaxes. Introducing these into our model as observations with error, we determine absolute parallaxes for each PNN. Weighted averaging with previous independent parallax measurements yields an average parallax precision, sigma (sub pi)/ pi = 5%. Derived distances are: d(sub NGC6853) = 405(exp +28 sub -25) pc, d(sub NGC7293) = 216(exp +14 sub -12) pc, d(sub Abell31) = 621(exp +91 sub -70) pc, and d(sub DeHt5) = 345(exp +19 sub -17) pc. These PNNi distances are all smaller than previously derived from spectroscopic analyses of the central stars. To obtain absolute magnitudes from these distances requires estimates of interstellar extinction. We average extinction measurements culled from the literature, from reddening based on PNNi intrinsic colors derived from model SEDs, and an assumption that each PNN experiences the same rate of extinction as a function of distance as do the reference stars nearest (in angular separation) to each central star. We also apply Lutz-Kelker bias corrections. The absolute magnitudes and effective temperatures permit estimates of PNNi radii through both the Stefan-Boltzmann relation and Eddington fluxes. Comparing absolute magnitudes with post-AGB models provides mass estimates. Masses cluster around 0.57 solar Mass, close to the peak of the white dwarf mass distribution. Adding a few more PNNi with well-determined distances and masses, we compare all the PNNi with cooler white dwarfs of similar mass, and confirm, as expected, that PNNi have larger radii than white dwarfs that have reached their final cooling tracks.

Validation of the Walking Impairment Questionnaire for Spanish patients.

PubMed

Lozano, Francisco S; March, José R; González-Porras, José R; Carrasco, Eduardo; Lobos, José M; Areitio-Aurtena, Alix

2013-09-01

The Walking Impairment Questionnaire (WIQ) is a short, easy to complete, disease-specific questionnaire to assess intermittent claudication. A Spanish version of the WIQ for Hispanic Americans has recently been validated in Texas, but it needs to be validated for European Spanish people. After translation and cultural adaptation of the WIQ, 920 patients with intermittent claudication (ankle brachial index < 0.9) completed two questionnaires (Spanish version of the WIQ and European Quality of Life 5 Dimension [EQ-5D]). The validity of the WIQ was determined by correlating WIQ and EQ-5D. Test-retest reliability and internal consistency were determined using the intra-class correlation coefficient (ICC) and Cronbach's alpha, respectively. The three domains of the WIQ were moderately correlated with the EQ-5D health outcome (r = 0.54 to 0.60; p < 0.001). Test-retest reliabilities ranged from ICC = 0.89 to 0.91 and internal consistency (Cronbach's alpha = 0.92) was high. The Spanish version of the WIQ for European Spanish patients was valid and reproducible, suggesting that it could be used in Spanish patients with intermittent claudication.

The orbit of Phi Cygni measured with long-baseline optical interferometry - Component masses and absolute magnitudes

NASA Technical Reports Server (NTRS)

Armstrong, J. T.; Hummel, C. A.; Quirrenbach, A.; Buscher, D. F.; Mozurkewich, D.; Vivekanand, M.; Simon, R. S.; Denison, C. S.; Johnston, K. J.; Pan, X.-P.

1992-01-01

The orbit of the double-lined spectroscopic binary Phi Cygni, the distance to the system, and the masses and absolute magnitudes of its components are presented via measurements with the Mar III Optical Interferometer. On the basis of a reexamination of the spectroscopic data of Rach & Herbig (1961), the values and uncertainties are adopted for the period and the projected semimajor axes from the present fit to the spectroscopic data and the values of the remaining elements from the present fit to the Mark III data. The elements of the true orbit are derived, and the masses and absolute magnitudes of the components, and the distance to the system are calculated.

Numerical model estimating the capabilities and limitations of the fast Fourier transform technique in absolute interferometry

NASA Astrophysics Data System (ADS)

Talamonti, James J.; Kay, Richard B.; Krebs, Danny J.

1996-05-01

A numerical model was developed to emulate the capabilities of systems performing noncontact absolute distance measurements. The model incorporates known methods to minimize signal processing and digital sampling errors and evaluates the accuracy limitations imposed by spectral peak isolation by using Hanning, Blackman, and Gaussian windows in the fast Fourier transform technique. We applied this model to the specific case of measuring the relative lengths of a compound Michelson interferometer. By processing computer-simulated data through our model, we project the ultimate precision for ideal data, and data containing AM-FM noise. The precision is shown to be limited by nonlinearities in the laser scan. absolute distance, interferometer.

PoleStriding exercise and vitamin E for management of peripheral vascular disease.

PubMed

Collins, Eileen G; Edwin Langbein, W; Orebaugh, Cynthia; Bammert, Christine; Hanson, Karla; Reda, Domenic; Edwards, Lonnie C; Littooy, Fred N

2003-03-01

The purpose of this investigation was to evaluate the efficacy of PoleStriding exercise (a form of walking that uses muscles of the upper and lower body in a continuous movement similar to cross-country skiing) and vitamin E (alpha-tocopherol) to improve walking ability and perceived quality of life (QOL) of patients with claudication pain secondary to peripheral arterial disease (PAD). Fifty-two subjects were randomized into four groups: PoleStriding with vitamin E (N = 13), PoleStriding with placebo (N= 14), vitamin E without exercise (N= 13), and placebo without exercise (N = 12). The dose of vitamin E was 400 IU daily. Only the PoleStriding with vitamin E and PoleStriding with placebo groups received PoleStriding instruction and training. Assignment to vitamin E or placebo was double blind. Subjects trained three times weekly for 30-45 min (rest time excluded). Individuals in vitamin E and placebo groups came to the laboratory biweekly for ankle blood-pressure measurements. Results of this randomized clinical trial provide strong evidence that PoleStriding significantly (P< 0.001) improved exercise tolerance on the constant work-rate and incremental treadmill tests. Ratings of perceived claudication pain were significantly less after the PoleStriding training program (P= 0.02). In contrast, vitamin E did not have a statistically significant effect on the subjects' ratings of perceived leg pain (P= 0.35) or treadmill walking duration ( P= 0.36). Perceived distance and walking speed (Walking Impairment Questionnaire) and perceived physical function (Rand Short Form-36) improved in the PoleStriding trained group only (P< 0.001, 0.022 and 0.003, respectively). PoleStriding effectively improved the exercise tolerance and perceived QOL of patients with PAD. Little additional benefit to exercise capacity was realized from vitamin E supplementation.

Exercise training for intermittent claudication.

PubMed

McDermott, Mary M

2017-11-01

The objective of this study was to provide an overview of evidence regarding exercise therapies for patients with lower extremity peripheral artery disease (PAD). This manuscript summarizes the content of a lecture delivered as part of the 2016 Crawford Critical Issues Symposium. Multiple randomized clinical trials demonstrate that supervised treadmill exercise significantly improves treadmill walking performance in people with PAD and intermittent claudication symptoms. A meta-analysis of 25 randomized trials demonstrated a 180-meter increase in treadmill walking distance in response to supervised exercise interventions compared with a nonexercising control group. Supervised treadmill exercise has been inaccessible to many patients with PAD because of lack of medical insurance coverage. However, in 2017, the Centers for Medicare and Medicaid Services issued a decision memorandum to support health insurance coverage of 12 weeks of supervised treadmill exercise for patients with walking impairment due to PAD. Recent evidence also supports home-based walking exercise to improve walking performance in people with PAD. Effective home-exercise programs incorporate behavioral change interventions such as a remote coach, goal setting, and self-monitoring. Supervised treadmill exercise programs preferentially improve treadmill walking performance, whereas home-based walking exercise programs preferentially improve corridor walking, such as the 6-minute walk test. Clinical trial evidence also supports arm or leg ergometry exercise to improve walking endurance in people with PAD. Treadmill walking exercise appears superior to resistance training alone for improving walking endurance. Supervised treadmill exercise significantly improves treadmill walking performance in people with PAD by approximately 180 meters compared with no exercise. Recent evidence suggests that home-based exercise is also effective and preferentially improves over-ground walking performance, such as the 6-minute walk test. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Absolute Depth Sensitivity in Cat Primary Visual Cortex under Natural Viewing Conditions.

PubMed

Pigarev, Ivan N; Levichkina, Ekaterina V

2016-01-01

Mechanisms of 3D perception, investigated in many laboratories, have defined depth either relative to the fixation plane or to other objects in the visual scene. It is obvious that for efficient perception of the 3D world, additional mechanisms of depth constancy could operate in the visual system to provide information about absolute distance. Neurons with properties reflecting some features of depth constancy have been described in the parietal and extrastriate occipital cortical areas. It has also been shown that, for some neurons in the visual area V1, responses to stimuli of constant angular size differ at close and remote distances. The present study was designed to investigate whether, in natural free gaze viewing conditions, neurons tuned to absolute depths can be found in the primary visual cortex (area V1). Single-unit extracellular activity was recorded from the visual cortex of waking cats sitting on a trolley in front of a large screen. The trolley was slowly approaching the visual scene, which consisted of stationary sinusoidal gratings of optimal orientation rear-projected over the whole surface of the screen. Each neuron was tested with two gratings, with spatial frequency of one grating being twice as high as that of the other. Assuming that a cell is tuned to a spatial frequency, its maximum response to the grating with a spatial frequency twice as high should be shifted to a distance half way closer to the screen in order to attain the same size of retinal projection. For hypothetical neurons selective to absolute depth, location of the maximum response should remain at the same distance irrespective of the type of stimulus. It was found that about 20% of neurons in our experimental paradigm demonstrated sensitivity to particular distances independently of the spatial frequencies of the gratings. We interpret these findings as an indication of the use of absolute depth information in the primary visual cortex.

Revascularization of smokers with claudication is not predicted to limit quality of life despite a higher risk of late failure.

PubMed

Mixson, Joshua D; Brothers, Thomas E

2017-01-01

Tobacco smoking after lower extremity revascularization for claudication has repeatedly been shown to increase the risk of adverse events, such that many vascular specialists consider that refusal to abstain from smoking constitutes a major contraindication to open surgical bypass or endovascular intervention. A Markov decision analysis (DA) model was used to compare the options of direct revascularization vs medical therapy only in smokers with claudication. The primary outcome was calculated quality of life (cQoL), determined for each patient at follow-up based on the outcomes of the treatment received. Markov DA software was used to predict the QoL for each treatment option preoperatively based on smoking status. Among patients referred during a recent 64-month period with vasculogenic claudication, 94 were actively smoking compared with 217 who were not. The DA model predicted that if the patients who smoked were to discontinue smoking, the best therapy would be bypass surgery for 77% and endovascular intervention for 17%. However, despite at least doubling the risks with intervention in the patients who continue to smoke, the DA model still predicted that 78% and 9% would fare better with open surgical or endovascular intervention, respectively. Among actively smoking patients, open surgical (3%) or endovascular (4%) therapies were initially performed in few patients, whereas 93% were offered only medical therapy. Among initial nonsmokers, revascularization was performed by open (27%) or endovascular (42%) means. At 3 years, the median (interquartile range [IQR]) cQoL was lower in initial smokers than in nonsmokers (0.73 [IQR, 0.73-0.77] vs 0.82 [IQR, 0.75-0.86]; P < .0001), primarily because of a lack of revascularization for smokers. Among initial smokers who did undergo revascularization initially, because of progression of symptoms, or after smoking cessation, cQoL was similar to initial nonsmokers (0.77 [IQR, 0.73-0.84] vs 0.73 [IQR, 0.73-0.73]; P = .37). Although 26% of initial smokers had stopped by the time of their last follow-up, 10% of initially nonsmoking patients were smoking at follow-up. However, among all patients undergoing intervention, the cQoL of patients smoking at the time of last their follow-up was similar to nonsmokers (0.82 [IQR, 0.82-0.86] vs 0.83 [IQR, 0.73-0.86]; P = .99). Patients with claudication who smoke may be denied the symptom improvement associated with revascularization, yet recidivism for smoking also occurs among patients who have stopped smoking in order to receive revascularization. The strategy not to directly revascularize patients with claudication who continue to smoke does not appear to maximize patient midterm QoL. Published by Elsevier Inc.

Measuring the Accuracy of Simple Evolving Connectionist System with Varying Distance Formulas

NASA Astrophysics Data System (ADS)

Al-Khowarizmi; Sitompul, O. S.; Suherman; Nababan, E. B.

2017-12-01

Simple Evolving Connectionist System (SECoS) is a minimal implementation of Evolving Connectionist Systems (ECoS) in artificial neural networks. The three-layer network architecture of the SECoS could be built based on the given input. In this study, the activation value for the SECoS learning process, which is commonly calculated using normalized Hamming distance, is also calculated using normalized Manhattan distance and normalized Euclidean distance in order to compare the smallest error value and best learning rate obtained. The accuracy of measurement resulted by the three distance formulas are calculated using mean absolute percentage error. In the training phase with several parameters, such as sensitivity threshold, error threshold, first learning rate, and second learning rate, it was found that normalized Euclidean distance is more accurate than both normalized Hamming distance and normalized Manhattan distance. In the case of beta fibrinogen gene -455 G/A polymorphism patients used as training data, the highest mean absolute percentage error value is obtained with normalized Manhattan distance compared to normalized Euclidean distance and normalized Hamming distance. However, the differences are very small that it can be concluded that the three distance formulas used in SECoS do not have a significant effect on the accuracy of the training results.

Gravitational acceleration as a cue for absolute size and distance?

NASA Technical Reports Server (NTRS)

Hecht, H.; Kaiser, M. K.; Banks, M. S.

1996-01-01

When an object's motion is influenced by gravity, as in the rise and fall of a thrown ball, the vertical component of acceleration is roughly constant at 9.8 m/sec2. In principle, an observer could use this information to estimate the absolute size and distance of the object (Saxberg, 1987a; Watson, Banks, von Hofsten, & Royden, 1992). In five experiments, we examined people's ability to utilize the size and distance information provided by gravitational acceleration. Observers viewed computer simulations of an object rising and falling on a trajectory aligned with the gravitational vector. The simulated objects were balls of different diameters presented across a wide range of simulated distances. Observers were asked to identify the ball that was presented and to estimate its distance. The results showed that observers were much more sensitive to average velocity than to the gravitational acceleration pattern. Likewise, verticality of the motion and visibility of the trajectory's apex had negligible effects on the accuracy of size and distance judgments.

Walking Capacity Is Positively Related with Heart Rate Variability in Symptomatic Peripheral Artery Disease.

PubMed

Lima, A H R A; Soares, A H G; Cucato, G G; Leicht, A S; Franco, F G M; Wolosker, N; Ritti-Dias, R M

2016-07-01

The aim was to investigate the association between walking capacity and HRV in patients with symptomatic peripheral artery disease (PAD). This was a cross sectional study. Ninety-five patients were recruited. Patients undertook a supine position for 20 minutes, with the final 10 minutes used to examine for resting HRV. Time domain, frequency domain, and non-linear indices were evaluated. A maximal treadmill test (Gardner protocol) was performed to assess maximal walking distance (MWD) and claudication distance (CD) in groups of PAD patients based upon their walking abilities (low, moderate, high). Differences between PAD patient groups were examined using non-parametric analyses, and Spearman rank correlations identified the relationship between MWD and CD, and HRV parameters. Symptomatic PAD patients with high MWD exhibited significantly greater HRV than patients with low MWD. Furthermore, MWD was positively associated with time domain and non-linear indices of HRV (all p < .05). However, no statistically significant correlations were observed between CD and HRV parameters or between PAD groups. A greater walking capacity is associated with better HRV in symptomatic PAD patients. Copyright © 2016 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Effect of Viewing Plane on Perceived Distances in Real and Virtual Environments

ERIC Educational Resources Information Center

Geuss, Michael N.; Stefanucci, Jeanine K.; Creem-Regehr, Sarah H.; Thompson, William B.

2012-01-01

Three experiments examined perceived absolute distance in a head-mounted display virtual environment (HMD-VE) and a matched real-world environment, as a function of the type and orientation of the distance viewed. In Experiment 1, participants turned and walked, without vision, a distance to match the viewed interval for both egocentric…

Gender and ethnic differences in arterial compliance in patients with intermittent claudication.

PubMed

Gardner, Andrew W; Montgomery, Polly S; Blevins, Steve M; Parker, Donald E

2010-03-01

To assess the gender and ethnic differences in arterial compliance in patients with intermittent claudication. A total of 114 patients participated, including 38 Caucasian men, 32 Caucasian women, 16 African American men, and 28 African American women. Patients were assessed on large artery elasticity index (LAEI), small artery elasticity index (SAEI), age, weight, body mass index, ankle-brachial index (ABI), smoking status, and metabolic syndrome components. Group differences were found for LAEI (P = .042), SAEI (P = .019), body mass index (P = .020), prevalence of elevated fasting glucose (P = .001), and prevalence of abdominal obesity (P = .025). Significant covariates for LAEI included age (P = .0002) and elevated triglycerides (P = .0719). LAEI (units = 10 mL x mm Hg) adjusted for age and triglycerides was 39% lower (P = .0005) in African Americans (11.4 +/- .90; mean +/- SE) than in Caucasians (15.8 +/- 0.72), whereas no significant difference (P = .7904) existed between men (13.8 +/- 0.81) and women (13.5 +/- 0.79). Significant covariates for SAEI included age (P = .0001), abdominal obesity (P = .0030), and elevated blood pressure (P = .0067). SAEI (units = 100 mL x mm Hg) adjusted for age, abdominal obesity, and elevated blood pressure was 32% lower (P = .0007) in African-Americans (2.8 +/- 0.3) than in Caucasians 4.1 +/- 0.2), and was 18% lower (P = .0442) in women (3.1 +/- 0.2) than in men (3.8 +/- 0.2). African American patients with intermittent claudication have more impaired macrovascular and microvascular function than Caucasian patients, and women have more impaired microvascular function than men. These ethnic and gender differences in arterial compliance are evident even though ABI was similar among groups, suggesting that arterial compliance provides unique information to quantify vascular impairment in patients with intermittent claudication.

Buttock Claudication and Erectile Dysfunction After Internal Iliac Artery Embolization in Patients Prior to Endovascular Aortic Aneurysm Repair

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rayt, H. S., E-mail: hsrayt@hotmail.com; Bown, M. J.; Lambert, K. V.

2008-07-15

Coil embolization of the internal iliac artery (IIA) is used to extend the application of endovascular aneurysm repair (EVAR) in cases of challenging iliac anatomy. Pelvic ischemia is a complication of the technique, but reports vary as to the rate and severity. This study reports our experience with IIA embolization and compares the results to those of other published series. The vascular unit database of the Leicester Royal Infirmary was used to identify patients who had undergone IIA coil embolization prior to EVAR. Data were collected from hospital case notes and by telephone interviews. Thirty-eight patients were identified; 29 ofmore » these were contactable by telephone. A literature search was performed for other studies of IIA embolization and the results were pooled. In this series buttock claudication occurred in 55% (16 of 29 patients) overall: in 52% of unilateral embolizations (11 of 21) and 63% of bilateral embolizations (5 of 8). New erectile dysfunction occurred in 46% (6 of 13 patients) overall: in 38% of unilateral embolizations (3 of 8) and 60% of bilateral embolizations (3 of 5). The literature review identified 18 relevant studies. The results were pooled with our results, to give 634 patients in total. Buttock claudication occurred in 28% overall (178 of 634 patients): in 31% of unilateral embolizations (99 of 322) and 35% of bilateral embolizations (34 of 98) (p = 0.46, Fisher's exact test). New erectile dysfunction occurred in 17% overall (27 of 159 patients): in 17% of unilateral embolizations (16 of 97) and 24% of bilateral embolizations (9 of 38) (p = 0.33). We conclude that buttock claudication and erectile dysfunction are frequent complications of IIA embolization and patients should be counseled accordingly.« less

[Medial longitudinal fasciculus (MLF) syndrome in a patient with giant cell arteritis].

PubMed

Uenaka, Takeshi; Hamaguchi, Hirotoshi; Sekiguchi, Kenji; Kowa, Hisatomo; Kanda, Fumio; Toda, Tatsushi

2015-01-01

A 76-year-old female was referred to our department because of diplopia for two months and intermittent claudication for five months. She showed medial longitudinal fasciculus (MLF) syndrome. Brain MRI (T2WI) showed multiple infarctions in the right pontine tegmentum and left paramedian midbrain. A biopsy of superficial temporal artery showed the characteristic findings of glanulomatous inflammation indicative of giant cell arteritis. We thought the mechanism of this cerebral infarction as artery to artery embolization or intracranial arteritis. Treatment with oral prednisolone (1 mg/kg/day) improved her limb claudication and normalized serum C-reactive protein level.

Abdominal Aortic Hemodynamics in Intermittent Claudication Patients at Rest and During Dynamic Pedaling Exercise

PubMed Central

Cheng, Christopher P.; Taylor, Charles A.; Dalman, Ronald L.

2015-01-01

Introduction Lower extremity exercise has been shown to eliminate adverse hemodynamics conditions, such as low and oscillating blood flow and wall shear stress, in the abdominal aortas of healthy young and older adults. Methods We use cine phase-contrast magnetic resonance imaging and a custom MRI-compatible exercise cycle to quantify hemodynamic changes due to pedaling exercise in patients diagnosed with intermittent claudication. Results and Conclusions With only an average heart increase of 35±18% and exercise workload of 36±16 Watts, the patients experienced approximately 3- and 6-fold increases in blood flow, and 4- and 16-fold increases in wall shear stress at the supraceliac and infrarenal aortic locations, respectively. Also, all oscillations in flow and shear stress at rest were eliminated with exercise. Claudication patients experience 3 to 4-fold lower oscillations in flow and shear stress at rest as compared to healthy age-matched controls, likely due to reduced distal arterial compliance as a result of distal atherosclerosis. The magnitude of flow and shear oscillatory indices may be good indicators of distal arterial compliance and health, and may provide predictive power for the efficacy of focal interventions. PMID:26315797

Method and apparatus for making absolute range measurements

DOEpatents

Allison, Stephen W.; Cates, Michael R.; Key, William S.; Sanders, Alvin J.; Earl, Dennis D.

1999-01-01

This invention relates to a method and apparatus for making absolute distance or ranging measurements using Fresnel diffraction. The invention employs a source of electromagnetic radiation having a known wavelength or wavelength distribution, which sends a beam of electromagnetic radiation through an object which causes it to be split (hereinafter referred to as a "beamsplitter"), and then to a target. The beam is reflected from the target onto a screen containing an aperture spaced a known distance from the beamsplitter. The aperture is sized so as to produce a Fresnel diffraction pattern. A portion of the beam travels through the aperture to a detector, spaced a known distance from the screen. The detector detects the central intensity of the beam. The distance from the object which causes the beam to be split to the target can then be calculated based upon the known wavelength, aperture radius, beam intensity, and distance from the detector to the screen. Several apparatus embodiments are disclosed for practicing the method embodiments of the present invention.

Method and apparatus for making absolute range measurements

DOEpatents

Allison, S.W.; Cates, M.R.; Key, W.S.; Sanders, A.J.; Earl, D.D.

1999-06-22

This invention relates to a method and apparatus for making absolute distance or ranging measurements using Fresnel diffraction. The invention employs a source of electromagnetic radiation having a known wavelength or wavelength distribution, which sends a beam of electromagnetic radiation through an object which causes it to be split (hereinafter referred to as a beam splitter''), and then to a target. The beam is reflected from the target onto a screen containing an aperture spaced a known distance from the beam splitter. The aperture is sized so as to produce a Fresnel diffraction pattern. A portion of the beam travels through the aperture to a detector, spaced a known distance from the screen. The detector detects the central intensity of the beam. The distance from the object which causes the beam to be split to the target can then be calculated based upon the known wavelength, aperture radius, beam intensity, and distance from the detector to the screen. Several apparatus embodiments are disclosed for practicing the method embodiments of the present invention. 9 figs.

Absolute Intra-Molecular Distance Measurements with Ångström-Resolution using Anomalous Small-Angle X-ray Scattering

DOE PAGES

Zettl, Thomas; Mathew, Rebecca S.; Seifert, Sönke; ...

2016-05-31

Accurate determination of molecular distances is fundamental to understanding the structure, dynamics, and conformational ensembles of biological macromolecules. Here we present a method to determine the full,distance,distribution between small (~7 Å) gold labels attached to macromolecules with very high-precision(≤1 Å) and on an absolute distance scale. Our method uses anomalous small-angle X-ray scattering close to a gold absorption edge to separate the gold-gold interference pattern from other scattering contributions. Results for 10-30 bp DNA constructs achieve excellent signal-to-noise and are in good agreement with previous results obtained by single-energy,SAXS measurements without requiring the preparation and measurement of single labeled andmore » unlabeled samples. Finally, the use of small gold labels in combination with ASAXS read out provides an attractive approach to determining molecular distance distributions that will be applicable to a broad range of macromolecular systems.« less

Method and apparatus for making absolute range measurements

DOEpatents

Earl, Dennis D [Knoxville, TN; Allison, Stephen W [Knoxville, TN; Cates, Michael R [Oak Ridge, TN; Sanders, Alvin J [Knoxville, TN

2002-09-24

This invention relates to a method and apparatus for making absolute distance or ranging measurements using Fresnel diffraction. The invention employs a source of electromagnetic radiation having a known wavelength or wavelength distribution, which sends a beam of electromagnetic radiation through a screen at least partially opaque at the wavelength. The screen has an aperture sized so as to produce a Fresnel diffraction pattern. A portion of the beam travels through the aperture to a detector spaced some distance from the screen. The detector detects the central intensity of the beam as well as a set of intensities displaced from a center of the aperture. The distance from the source to the target can then be calculated based upon the known wavelength, aperture radius, and beam intensity.

Type Ia supernovae as standard candles

NASA Technical Reports Server (NTRS)

Branch, David; Miller, Douglas L.

1993-01-01

The distribution of absolute blue magnitudes among Type Ia supernovae (SNs Ia) is studied. Supernovae were used with well determined apparent magnitudes at maximum light and parent galaxies with relative distances determined by the Tully-Fisher or Dn - sigma techniques. The mean absolute blue magnitude is given and the observational dispersion is only sigma(MB) 0.36, comparable to the expected combined errors in distance, apparent magnitude, and extinction. The mean (B-V) color at maximum light is 0.03 +/- 0.04, with a dispersion sigma(B-V) = 0.20. The Cepheid-based distance to IC 4182, the parent galaxy of the normal and unextinguished Type Ia SN 1937C, leads to a Hubble constant of H(0) + 51 +/- 12 km/s Mpc. The existence of a few SNs Ia that appear to have been reddened and dimmed by dust in their parent galaxies does not seriously compromise the use of SNs Ia as distance indicators.

Absolute and relative cues for the auditory perception of egocentric distance.

PubMed

Mershon, D H; Bowers, J N

1979-01-01

Three experiments were performed to examine the reverberation cue to egocentric auditory distance and to determine the extent to which such a cue could provide 'absolute', as contrasted with 'relative', information about distance. In experiment 1 independent groups of blindfolded observers (200 altogether) were presented with broadband noise from a speaker at one of five different distances (0.55 to 8 m) in a normal hard-walled room. Half of each group of observers were presented with the sound at 0 deg azimuth, followed (after a delay) by the identical sound at 90 deg azimuth. The order of presentation was reversed for the remaining observers. Perceived distance varied significantly as a function of the physical distance to the speaker, even for the first presentations. The change in the binaural information between the 0 deg and 90 deg presentations did not significantly modify the results. For both orientations, near distances were overestimated and far distances were underestimated. Experiment 2 and 3 were designed to evaluate how much prior auditory exposure to the laboratory environment was necessary. A 200 Hz square-wave signal was presented from one of three distances (1, 2, or 6 m) to observers who had either minimal room information or an exposure which included talking within the room. Perceived distance varied significantly with physical distance regardless to exposure condition.

[Lumbar spondylosis].

PubMed

Seichi, Atsushi

2014-10-01

Lumbar spondylosis is a chronic, noninflammatory disease caused by degeneration of lumbar disc and/or facet joints. The etiology of lumbar spondylosis is multifactorial. Patients with lumbar spondylosis complain of a broad variety of symptoms including discomfort in the low back lesion, whereas some of them have radiating leg pain or neurologenic intermittent claudication (lumbar spinal stenosis). The majority of patients with spondylosis and stenosis of the lumbosacral spine can be treated nonsurgically. Nonsteroidal anti-inflammatory drugs and COX-2 inhibitors are helpful in controlling symptoms. Prostaglandin, epidural injection, and transforaminal injection are also helpful for leg pain and intermittent claudication. Operative therapy for spinal stenosis or spondylolisthesis is reserved for patients who are totally incapacitated by their condition.

Estimates of the absolute error and a scheme for an approximate solution to scheduling problems

NASA Astrophysics Data System (ADS)

Lazarev, A. A.

2009-02-01

An approach is proposed for estimating absolute errors and finding approximate solutions to classical NP-hard scheduling problems of minimizing the maximum lateness for one or many machines and makespan is minimized. The concept of a metric (distance) between instances of the problem is introduced. The idea behind the approach is, given the problem instance, to construct another instance for which an optimal or approximate solution can be found at the minimum distance from the initial instance in the metric introduced. Instead of solving the original problem (instance), a set of approximating polynomially/pseudopolynomially solvable problems (instances) are considered, an instance at the minimum distance from the given one is chosen, and the resulting schedule is then applied to the original instance.

Perioperative outcomes of elective inflow revascularization for lower extremity claudication in the American College of Surgeons National Surgical Quality Improvement Program database.

PubMed

Madenci, Arin L; Ozaki, C Keith; Gupta, Naren; Raffetto, Joseph D; Belkin, Michael; McPhee, James T

2016-09-01

We compared the early postoperative morbidity and mortality rates of contemporary aortofemoral bypass (AFB) and other inflow procedures for claudication. We identified 1974 claudicants who underwent elective AFB (n = 566) or non-AFB (nonaortofemoral bypass [NAFB]; n = 1408) inflow reconstruction using the ACS-NSQIP database (2005 to 2012). Stent placement was not routinely captured. In propensity score-matched cohorts, we analyzed the association between type of inflow surgery and 30-day postoperative outcomes. Among 824 propensity score-matched patients (AFB, n = 412; NAFB, n = 412), the 30-day mortality rate was 2.7% for AFB and .0% for NAFB (P = .0008). NAFB conferred significantly lower rates of major cardiac (.2% vs 2.4%, P = .0063), respiratory (.7% vs 10.9%, P < .0001), renal (.2% vs 1.9%, P = .0380), and septic (.5% vs 3.6%, P = .0014) complications, and fewer returns to the operating room (4.6% vs 9.9%, P = .0032), compared with AFB. Rates of major venous thrombosis, wound complications, peripheral nerve injury, and graft failure were similar between the groups. This study reports a higher contemporary short-term complication rate with AFB compared to alternative inflow revascularization, against which future study of long-term durability may be weighed. Published by Elsevier Inc.

Clinical impact of exercise in patients with peripheral arterial disease.

PubMed

Novakovic, Marko; Jug, Borut; Lenasi, Helena

2017-08-01

Increasing prevalence, high morbidity and mortality, and decreased health-related quality of life are hallmarks of peripheral arterial disease. About one-third of peripheral arterial disease patients have intermittent claudication with deleterious effects on everyday activities, such as walking. Exercise training improves peripheral arterial disease symptoms and is recommended as first line therapy for peripheral arterial disease. This review examines the effects of exercise training beyond improvements in walking distance, namely on vascular function, parameters of inflammation, activated hemostasis and oxidative stress, and quality of life. Exercise training not only increases walking distance and physiologic parameters in patients with peripheral arterial disease, but also improves the cardiovascular risk profile by helping patients achieve better control of hypertension, hyperglycemia, obesity and dyslipidemia, thus further reducing cardiovascular risk and the prevalence of coexistent atherosclerotic diseases. American guidelines suggest supervised exercise training, performed for a minimum of 30-45 min, at least three times per week, for at least 12 weeks. Walking is the most studied exercise modality and its efficacy in improving cardiovascular parameters in patients with peripheral arterial disease has been extensively proven. As studies have shown that supervised exercise training improves walking performance, cardiovascular parameters and quality of life in patients with peripheral arterial disease, it should be encouraged and more often prescribed.

Clinical and Functional Impact of Hypogastric Artery Exclusion During EVAR.

PubMed

Mansour, Wassim; Capoccia, Laura; Sirignano, Pasqualino; Montelione, Nunzio; Pranteda, Chiara; Formiconi, Martina; Sbarigia, Enrico; Speziale, Francesco

2016-10-01

Hypogastric artery (HA) revascularization during endovascular aneurysm repair (EVAR) is still open to debate. Moreover, exclusion-related complication rates reported in literature are not negligible. The aim of this study is to present and analyze the outcomes in patients undergoing EVAR with exclusion of 1 or both HAs at our academic center. We retrospectively reviewed our results in patients submitted to EVAR and needing HA exclusion, in terms of perioperative (30-day) and follow-up rates of intestinal and spinal cord ischemia, buttock claudication, buttock skin necrosis, and sexual dysfunction. From January 2008 to December 2014, a total of 527 patients underwent elective standard infrarenal EVAR; among those 104 (19.7%) had iliac involvement needing HA exclusion. In 73 patients with unilateral iliac involvement (70.1%, group UH), many single HAs were excluded. Thirty-one patients (29.9%) had bilateral iliac involvement (group BH), of which 16 (51.6%) had 1 HA excluded with revascularization of the contralateral one (group BHR); in the remaining 15 patients (48.4%) both HAs were excluded (group BHE). No 30-day or follow-up aneurysm-related mortality, intestinal, or spinal cord ischemia were recorded. At 30 days, skin necrosis was observed in 2 patients. Buttock claudication and sexual dysfunction rates were significantly greater in group BHE than in group BHR (P < .05). At a mean 18.6 months follow-up (range: 4-47), buttock claudication and sexual dysfunction rates in group BHE were persistently higher than that in groups UH and BHR (P < .05); HA coil embolization was significantly associated with buttock claudication and sexual dysfunction (P < .05). Whenever anatomically feasible, at least 1 HA should be salvaged in case of bilateral involvement. In case of unilateral HA exclusion, the rate of complications is not negligible. Coil embolization is related to a higher complication rate. © The Author(s) 2016.

MiDAS ENCORE: Randomized Controlled Study Design and Protocol.

PubMed

Benyamin, Ramsin M; Staats, Peter S

2015-01-01

Epidural steroid injections (ESIs) are commonly used for treatment of symptomatic lumbar spinal stenosis (LSS). ESIs are generally administered after failure of conservative therapy. For LSS patients suffering from neurogenic claudication, the mild® procedure provides an alternative to ESIs via minimally invasive lumbar decompression. Both ESIs and mild offer interventional pain treatment options for LSS patients experiencing neurogenic claudication refractory to more conservative therapies. Prospective, multi-center, randomized controlled, clinical study. Twenty-six interventional pain management centers throughout the United States. To compare patient outcomes following treatment with either mild or ESIs in LSS patients with neurogenic claudication and having verified ligamentum flavum hypertrophy. Study participants include Medicare beneficiaries who meet study inclusion/exclusion criteria. Eligible patients will be randomized in a 1:1 ratio to one of 2 treatment arms, mild (treatment group) or ESI (control group). Each study group will include approximately 150 patients who have experienced neurogenic claudication symptoms for ≥ 3 months duration who have failed to respond to physical therapy, home exercise programs, and oral analgesics. Those randomized to mild are prohibited from receiving lumbar ESIs during the study period, while those randomized to ESI may receive ESIs up to 4 times per year. Patient assessments will occur at baseline, 6 months, and one year. An additional assessment will be conducted for the mild patient group at 2 years. The primary efficacy outcome measure is the proportion of Oswestry Disability Index (ODI) responders from baseline to one year follow-up in the treatment group (mild) versus the control group (ESI). ODI responders are defined as those patients achieving the validated Minimal Important Change (MIC) of ≥ 10 point improvement in ODI from baseline to follow-up as a clinically significant efficacy threshold. Secondary efficacy outcome measures include the proportion of Zurich Claudication Questionnaire (ZCQ) and Numeric Pain Rating Scale (NPRS) responders from baseline to follow-up using validated MIC thresholds. Improvement in ZCQ domains of ≥ 0.5 is considered significant, and a Patient Satisfaction score of at least 2.5 represents a satisfied patient. A reduction of ≥ 2 points in NPRS is considered significant pain relief. The primary safety outcome measure is the incidence of device- and/or procedure-related adverse events. Descriptive summaries will be presented by randomized group for all outcome measures at baseline and follow-up time points. Inferential statistical analysis will be conducted to determine significant differences related to functional improvement, pain relief, and safety outcomes. Primary study results will be presented based on one-year follow-up data, with an interim analysis report when 6-month follow-up data become available. Patients are not blinded due to significant differences in treatment protocols between study groups. Also, since neither study arm is focused on treatment of radicular pain, there may be a higher non-responder rate for both groups versus standard of care due to study restrictions on adjunctive pain therapies. This prospective, multi-center, randomized controlled study will provide Level I evidence of the safety and effectiveness of mild versus ESIs in managing neurogenic claudication symptoms in LSS patients.

MiDAS ENCORE: Randomized Controlled Clinical Trial Report of 6-Month Results.

PubMed

Staats, Peter S; Benyamin, Ramsin M

2016-02-01

Patients suffering from neurogenic claudication due to lumbar spinal stenosis (LSS) often experience moderate to severe pain and significant functional disability. Neurogenic claudication results from progressive degenerative changes in the spine, and most often affects the elderly. Both the MILD® procedure and epidural steroid injections (ESIs) offer interventional pain treatment options for LSS patients experiencing neurogenic claudication refractory to more conservative therapies. MILD provides an alternative to ESIs via minimally invasive lumbar decompression. Prospective, multi-center, randomized controlled clinical trial. Twenty-six US interventional pain management centers. To compare patient outcomes following treatment with either MILD (treatment group) or ESIs (active control group) in LSS patients with neurogenic claudication and verified ligamentum flavum hypertrophy. This prospective, multi-center, randomized controlled clinical trial includes 2 study arms with a 1-to-1 randomization ratio. A total of 302 patients were enrolled, with 149 randomized to MILD and 153 to the active control. Six-month follow-up has been completed and is presented in this report. In addition, one year follow-up will be conducted for patients in both study arms, and supplementary 2 year outcome data will be collected for patients in the MILD group only. Outcomes are assessed using the Oswestry Disability Index (ODI), numeric pain rating scale (NPRS) and Zurich Claudication Questionnaire (ZCQ). Primary efficacy is the proportion of ODI responders, tested for statistical superiority of the MILD group versus the active control group. ODI responders are defined as patients achieving the validated Minimal Important Change (MIC) of =10 point improvement in ODI from baseline to follow-up. Similarly, secondary efficacy includes proportion of NPRS and ZCQ responders using validated MIC thresholds. Primary safety is the incidence of device or procedure-related adverse events in each group. At 6 months, all primary and secondary efficacy results provided statistically significant evidence that MILD is superior to the active control. For primary efficacy, the proportion of ODI responders in the MILD group (62.2%) was statistically significantly higher than for the epidural steroid group (35.7%) (P < 0.001). Further, all secondary efficacy parameters demonstrated statistical superiority of MILD versus the active control. The primary safety endpoint was achieved, demonstrating that there is no difference in safety between MILD and ESIs (P = 1.00). Limitations include lack of patient blinding due to considerable differences in treatment protocols, and a potentially higher non-responder rate for both groups versus standard-of-care due to study restrictions on adjunctive pain therapies. Six month follow-up data from this trial demonstrate that the MILD procedure is statistically superior to epidural steroids, a known active treatment for LSS patients with neurogenic claudication and verified central stenosis due to ligamentum flavum hypertrophy. The results of all primary and secondary efficacy outcome measures achieved statistically superior outcomes in the MILD group versus ESIs. Further, there were no statistically significant differences in the safety profile between study groups. This prospective, multi-center, randomized controlled clinical trial provides strong evidence of the effectiveness of MILD versus epidural steroids in this patient population. NCT02093520.

The role of stenosis ratio as a predictor of surgical satisfaction in patients with lumbar spinal canal stenosis: a receiver-operator characteristic (ROC) curve analysis.

PubMed

Mohammadi, Hassanreza R; Azimi, Parisa; Benzel, Edward C; Shahzadi, Sohrab; Azhari, Shirzad

2016-09-01

The aim of this study was to elucidate independent factors that predict surgical satisfaction in lumbar spinal canal stenosis (LSCS) patients. Patients who underwent surgery were grouped based on the age, gender, duration of symptoms, walking distance, Neurogenic Claudication Outcome Score (NCOS) and the stenosis ratio (SR) described by Lurencin. We recorded on 2-year patient satisfaction using standardized measure. The optimal cut-off points in SR, NCOS and walking distance for predicting surgical satisfaction were estimated from sensitivity and specificity calculations and receiver operator characteristic (ROC) curves. One hundred fifty consecutive patients (51 male, 99 female, mean age 62.4±10.9 years) were followed up for 34±13 months (range 24-49). One, two, three and four level stenosis was observed in 10.7%, 39.3%, 36.0 % and 14.0% of patients, respectively. Post-surgical satisfaction was 78.5% at the 2 years follow up. In ROC curve analysis, the asymptotic significance is less than 0.05 in SR and the optimal cut-off value of SR to predict worsening surgical satisfaction was measured as more than 0.52, with 85.4% sensitivity and 77.4% specificity (AUC 0.798, 95% CI 0.73-0.90; P<0.01). The present study suggests that the SR, with a cut-off set a 0.52 cross-sectional area, may be superior to walking distance and NCOS in patients with degenerative lumbar stenosis considered for surgical treatment. Using a ROC curve analysis, a radiological feature, the SR, demonstrated superiority in predicting patient satisfaction, compared to functional and clinical characteristics such as walking distance and NCOS.

Large Magellanic Cloud Distance and Structure from Near-Infrared Red Clump Observations

NASA Astrophysics Data System (ADS)

Koerwer, Joel F.

2009-07-01

We have applied the Infrared Survey Facility Magellanic Clouds Point-Source Catalog to the mapping of the red clump (RC) distance modulus across the Large Magellanic Cloud (LMC). Using the J- (1.25 μm) and H- (1.63 μm) band data to derive a reddening free luminosity function and a theoretical RC absolute magnitude from stellar evolution libraries, we estimate a distance modulus to the LMC of μ = 18.54 ± 0.06. The best fitting plane inclination, i, and the position angle of the line of nodes, phi, have little dependence on the assumed RC absolute magnitude; we find i = 23fdg5 ± 0fdg4 and phi = 154fdg6 ± 1fdg2. It was also noted that many fields included a significant asymptotic giant branch bump population that must be accounted for.

Claudication

MedlinePlus

... limbs are damaged, usually as a result of atherosclerosis. Atherosclerosis can develop in any of your arteries, especially those in your heart. When atherosclerosis affects your arms and legs, it's called peripheral ...

Unilateral iliofemoral occlusive disease: long-term results of the semi-closed endarterectomy with the ring-stripper.

PubMed

van den Dungen, J J; Boontje, A H; Kropveld, A

1991-11-01

Nowadays, fewer endarterectomies are performed for treatment of occlusive arterial disease; more often a bypass procedure is done. This study investigates whether the results of the semiclosed endarterectomy for unilateral iliofemoral occlusive disease indeed indicate a wider use of bypass procedures for such short obstructions. Ninety-four patients with an obstructed external iliac and common femoral artery, but with patent ipsilateral common iliac and contralateral iliac arteries, underwent 101 operations. Seven of these patients were operated on at a later stage for occlusive disease on the contralateral side. Ninety-three endarterectomies were performed, and an iliofemoral bypass graft was inserted eight times because an endarterectomy was not feasible. Sixty-two operations were performed for disabling claudication, and 39 operations were performed for limb-threatening ischemia. Eighty-five percent of the patients who underwent an endarterectomy for disabling claudication became asymptomatic. Eighty percent of the patients who underwent an endarterectomy for limb-threatening ischemia became asymptomatic or improved to claudication. After endarterectomy no deaths, false aneurysms, or infections occurred. The patency rates at 1, 5, and 10 years were 94%, 83%, and 65%, respectively. We conclude that the semiclosed endarterectomy with the ringstripper of a unilateral obstruction of one external iliac and common femoral artery can be performed with a low morbidity and without deaths and gives good long-term results.

[Doppler study of gluteal arteries. A useful tool for excluding gluteal arterial pathology snd an important adjunct to lower limb Doppler studies].

PubMed

Bruninx, G; Salame, H; Wery, D; Delcour, C

2002-02-01

1) To determine the negative predictive value (VPN) of duplex scan in patients complaining of buttock or hip pain and thereby to distinguish vascular claudication from other musculoskeletal or neurological diseases. 2) To show its complementarity in doppler investigation of lower limb arteries. Prospective study by duplex scan and arteriography of 60 gluteal arteries in 30 consecutive patients referred to check up for lower limb arteriopathy or sexual impotence. Duplex scan was performed by posterior approach. Correlation between doppler ultrasound and arteriography was studied. The study of normal arteries was possible in all cases and only one normal gluteal artery could not be detected in a diabetic overweight patient. On 60 arteries, sensitivity of duplex was 100 percent, specificity 96 percent and VPN 100 percent. Significant obstructive lesions were always associated with pathological velocimetric waveform or were not detected. Buttock claudication can appear like a typical vascular claudication or mimic neurological or musculoskeletal diseases. It is very useful to rule out a vascular causality responsible for buttock or hip pain by simple, non-invasive and cheap exploration. A normal doppler ultrasound of gluteal arteries can rule out vascular disease responsible for buttock or hip pain thereby avoiding arteriography. The strategy of diagnostic or therapy can be modified by such additional information as shown in two case reports.

Self-mixing instrument for simultaneous distance and speed measurement

NASA Astrophysics Data System (ADS)

Norgia, Michele; Melchionni, Dario; Pesatori, Alessandro

2017-12-01

A novel instrument based on Self-mixing interferometry is proposed to simultaneously measure absolute distance and velocity. The measurement method is designed for working directly on each kind of surface, in industrial environment, overcoming also problems due to speckle pattern effect. The laser pump current is modulated at quite high frequency (40 kHz) and the estimation of the induced fringes frequency allows an almost instantaneous measurement (measurement time equal to 25 μs). A real time digital elaboration processes the measurement data and discards unreliable measurements. The simultaneous measurement reaches a relative standard deviation of about 4·10-4 in absolute distance, and 5·10-3 in velocity measurement. Three different laser sources are tested and compared. The instrument shows good performances also in harsh environment, for example measuring the movement of an opaque iron tube rotating under a running water flow.

Line-scan spectrum-encoded imaging by dual-comb interferometry.

PubMed

Wang, Chao; Deng, Zejiang; Gu, Chenglin; Liu, Yang; Luo, Daping; Zhu, Zhiwei; Li, Wenxue; Zeng, Heping

2018-04-01

Herein, the method of spectrum-encoded dual-comb interferometry is introduced to measure a three-dimensional (3-D) profile with absolute distance information. By combining spectral encoding for wavelength-to-space mapping, dual-comb interferometry for decoding and optical reference for calibration, this system can obtain a 3-D profile of an object at a stand-off distance of 114 mm with a depth precision of 12 μm. With the help of the reference arm, the absolute distance, reflectivity distribution, and depth information are simultaneously measured at a 5 kHz line-scan rate with free-running carrier-envelope offset frequencies. To verify the concept, experiments are conducted with multiple objects, including a resolution test chart, a three-stair structure, and a designed "ECNU" letter chain. The results show a horizontal resolution of ∼22  μm and a measurement range of 1.93 mm.

MILD® Is an Effective Treatment for Lumbar Spinal Stenosis with Neurogenic Claudication: MiDAS ENCORE Randomized Controlled Trial.

PubMed

Benyamin, Ramsin M; Staats, Peter S; MiDAS Encore, Investigators

2016-05-01

Lumbar spinal stenosis (LSS) is a common degenerative condition of the spine, which is a major cause of pain and functional disability for the elderly. Neurogenic claudication symptoms are a hallmark of LSS, where patients develop low back or leg pain when walking or standing that is relieved by sitting or lumbar flexion. The treatment of LSS generally begins with conservative management such as physical therapy, home exercise programs, and oral analgesics. Once these therapies fail, patients commonly move forward with interventional pain treatment options such as epidural steroid injections (ESIs) or MILD® as the next step. To assess improvement of function and reduction in pain for Medicare beneficiaries following treatment with MILD (treatment group) in LSS patients with neurogenic claudication and verified ligamentum flavum hypertrophy and to compare to a control group receiving ESIs. Prospective, multi-center, randomized controlled clinical trial. Twenty-six US interventional pain management centers. Patients in this trial were randomized one to one into 2 study arms. A total of 302 patients were enrolled, with 149 randomized to MILD and 153 to the active control. Outcomes are assessed using the Oswestry Disability Index (ODI), Numeric Pain Rating Scale (NPRS) and Zurich Claudication Questionnaire (ZCQ). Primary efficacy is the proportion of ODI responders, tested for statistical superiority of the MILD group versus the ESI group. ODI responders are defined as patients achieving the validated Minimal Important Change (MIC) of = 10 point improvement in ODI from baseline to follow-up. Similarly, secondary efficacy is the proportion of NPRS and ZCQ responders using validated MIC thresholds. Primary safety is the incidence of device- or procedure-related adverse events in each group. This report presents safety and efficacy results at 1-year follow-up. Outcomes at 2 years will be collected and reported for patients in the MILD group only. At 1-year follow-up, ODI, NPRS, and all 3 ZCQ domains (Symptom Severity, Physical Function and Patient Satisfaction) demonstrated statistically significant superiority of MILD versus the active control. For primary efficacy, the 58.0% ODI responder rate in the MILD group was higher than the 27.1% responder rate in the epidural steroid group (P < 0.001). The primary safety endpoint was achieved, demonstrating that there is no difference in safety between MILD and ESIs (P = 1.00). There was a lack of patient blinding due to considerable differences in treatment protocols, and a potentially higher non-responder rate for both groups versus standard-of-care due to adjunctive pain therapy study restrictions. Study enrollment was not limited to patients that had never received ESI therapy. One-year results of this randomized controlled clinical trial demonstrate that MILD is statistically superior to ESIs in the treatment of LSS patients with neurogenic claudication and verified central stenosis due to ligamentum flavum hypertrophy. Primary and secondary efficacy outcome measures achieved statistical superiority in the MILD group compared to the control group. With 95% of patients in this study presenting with 5 or more LSS co-factors, it is important to note that patients with spinal co-morbidities also experienced statistically significant improved function that was durable through 1 year. MILD, minimally invasive lumbar decompression, interlaminar epidural steroid injections, ESI neurogenic claudication, ligamentum flavum, ENCORE, PILD, CED Study, LSS.

Absolute Ages and Distances of 22 GCs Using Monte Carlo Main-sequence Fitting

NASA Astrophysics Data System (ADS)

O'Malley, Erin M.; Gilligan, Christina; Chaboyer, Brian

2017-04-01

The recent Gaia Data Release 1 of stellar parallaxes provides ample opportunity to find metal-poor main-sequence stars with precise parallaxes. We select 21 such stars with parallax uncertainties better than σ π /π ≤ 0.10 and accurate abundance determinations suitable for testing metal-poor stellar evolution models and determining the distance to Galactic globular clusters (GCs). A Monte Carlo analysis was used, taking into account uncertainties in the model construction parameters, to generate stellar models and isochrones to fit to the calibration stars. The isochrones that fit the calibration stars best were then used to determine the distances and ages of 22 GCs with metallicities ranging from -2.4 dex to -0.7 dex. We find distances with an average uncertainty of 0.15 mag and absolute ages ranging from 10.8 to 13.6 Gyr with an average uncertainty of 1.6 Gyr. Using literature proper motion data, we calculate orbits for the clusters, finding six that reside within the Galactic disk/bulge, while the rest are considered halo clusters. We find no strong evidence for a relationship between age and Galactocentric distance, but we do find a decreasing age-[Fe/H] relation.

Clinical validity of a disease-specific health status questionnaire: the peripheral artery questionnaire.

PubMed

Hoeks, Sanne E; Smolderen, Kim G; Scholte Op Reimer, Wilma J M; Verhagen, Hence J M; Spertus, John A; Poldermans, Don

2009-02-01

Measuring patient-centered outcomes is becoming increasingly important in patients with peripheral arterial disease (PAD), both as a means of determining the benefits of treatment and as an aid for disease management. In order to monitor health status in a reliable and sensitive way, the disease-specific measure Peripheral Artery Questionnaire (PAQ) was developed. However, to date, its correlation with traditional clinical indices is unknown. The primary aim of this study was to better establish the clinical validity of the PAQ by examining its association with functional indices related to PAD. Furthermore, we hypothesized that the clinical validity of this disease-specific measure is better as compared with the EuroQol-5-dimensional (EQ-5D), a standardized generic instrument. Data on 711 consecutive PAD patients undergoing surgery were collected from 11 Dutch hospitals in 2004. At 3-year follow-up, questionnaires including the PAQ, EQ-5D, and EuroQol-Visual Analogue Scale (EQ VAS) were completed in 84% of survivors. The PAQ was analyzed according to three domains, as established by a factor analyses in the Dutch population, and the summary score. Baseline clinical indices included the presence and severity of claudication intermittent (CI) and the Lee Cardiac Risk Index. All three PAQ domains (Physical Function, Perceived Disability, and Treatment Satisfaction) were significantly associated with CI symptoms (P values < .001-.008). Patients with claudication had significant lower PAQ summary scores as compared with asymptomatic patients (58.6 +/- 27.8 vs 68.6 +/- 27.8, P = < .001). Furthermore, the PAQ summary score and the subscale scores for Physical Functioning and Perceived Disability demonstrated a clear dose-response relation for walking distance and the Lee Risk Index (P values < .001-.031). With respect to the generic EQ-5D, the summary EQ-5D index was associated with CI (0.81 +/- 0.20 vs 0.76 +/- 0.24, P = .031) but not with walking distance (P = .128) nor the Lee Risk Index (P = .154). The EQ VAS discriminated between the clinical indices (P values = .003-.008), although a clear dose-response relation was lacking. The clinical validity of the PAQ proved to be good as the PAQ subscales discriminated well between patients with or without symptomatic PAD and its severity as defined by walking distance. Furthermore, the PAQ subscales were directly proportional to the presence and number of risk factors relevant for PAD. For studying outcomes in PAD patients, the disease-specific PAQ is likely to be a more sensitive measure of treatment benefit as compared with the generic EQ VAS, although the latter may still be of value when comparing health status across different diseases. Regarding disease management, we advocate the use of the disease-specific PAQ as its greater sensitivity and validity will assist its translation into clinical practice.

Evaluation of Cell Therapy on Exercise Performance and Limb Perfusion in Peripheral Artery Disease: The CCTRN PACE Trial (Patients With Intermittent Claudication Injected With ALDH Bright Cells).

PubMed

Perin, Emerson C; Murphy, Michael P; March, Keith L; Bolli, Roberto; Loughran, John; Yang, Phillip C; Leeper, Nicholas J; Dalman, Ronald L; Alexander, Jason; Henry, Timothy D; Traverse, Jay H; Pepine, Carl J; Anderson, R David; Berceli, Scott; Willerson, James T; Muthupillai, Raja; Gahremanpour, Amir; Raveendran, Ganesh; Velasquez, Omaida; Hare, Joshua M; Hernandez Schulman, Ivonne; Kasi, Vijaykumar S; Hiatt, William R; Ambale-Venkatesh, Bharath; Lima, João A; Taylor, Doris A; Resende, Micheline; Gee, Adrian P; Durett, April G; Bloom, Jeanette; Richman, Sara; G'Sell, Patricia; Williams, Shari; Khan, Fouzia; Gyang Ross, Elsie; Santoso, Michelle R; Goldman, JoAnne; Leach, Dana; Handberg, Eileen; Cheong, Benjamin; Piece, Nichole; DiFede, Darcy; Bruhn-Ding, Barb; Caldwell, Emily; Bettencourt, Judy; Lai, Dejian; Piller, Linda; Simpson, Lara; Cohen, Michelle; Sayre, Shelly L; Vojvodic, Rachel W; Moyé, Lem; Ebert, Ray F; Simari, Robert D; Hirsch, Alan T

2017-04-11

Atherosclerotic peripheral artery disease affects 8% to 12% of Americans >65 years of age and is associated with a major decline in functional status, increased myocardial infarction and stroke rates, and increased risk of ischemic amputation. Current treatment strategies for claudication have limitations. PACE (Patients With Intermittent Claudication Injected With ALDH Bright Cells) is a National Heart, Lung, and Blood Institute-sponsored, randomized, double-blind, placebo-controlled, phase 2 exploratory clinical trial designed to assess the safety and efficacy of autologous bone marrow-derived aldehyde dehydrogenase bright (ALDHbr) cells in patients with peripheral artery disease and to explore associated claudication physiological mechanisms. All participants, randomized 1:1 to receive ALDHbr cells or placebo, underwent bone marrow aspiration and isolation of ALDHbr cells, followed by 10 injections into the thigh and calf of the index leg. The coprimary end points were change from baseline to 6 months in peak walking time (PWT), collateral count, peak hyperemic popliteal flow, and capillary perfusion measured by magnetic resonance imaging, as well as safety. A total of 82 patients with claudication and infrainguinal peripheral artery disease were randomized at 9 sites, of whom 78 had analyzable data (57 male, 21 female patients; mean age, 66±9 years). The mean±SEM differences in the change over 6 months between study groups for PWT (0.9±0.8 minutes; 95% confidence interval [CI] -0.6 to 2.5; P =0.238), collateral count (0.9±0.6 arteries; 95% CI, -0.2 to 2.1; P=0.116), peak hyperemic popliteal flow (0.0±0.4 mL/s; 95% CI, -0.8 to 0.8; P =0.978), and capillary perfusion (-0.2±0.6%; 95% CI, -1.3 to 0.9; P=0.752) were not significant. In addition, there were no significant differences for the secondary end points, including quality-of-life measures. There were no adverse safety outcomes. Correlative relationships between magnetic resonance imaging measures and PWT were not significant. A post hoc exploratory analysis suggested that ALDHbr cell administration might be associated with an increase in the number of collateral arteries (1.5±0.7; 95% CI, 0.1-2.9; P =0.047) in participants with completely occluded femoral arteries. ALDHbr cell administration did not improve PWT or magnetic resonance outcomes, and the changes in PWT were not associated with the anatomic or physiological magnetic resonance imaging end points. Future peripheral artery disease cell therapy investigational trial design may be informed by new anatomic and perfusion insights. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01774097. © 2017 American Heart Association, Inc.

Application of adaptive design and decision making to a phase II trial of a phosphodiesterase inhibitor for the treatment of intermittent claudication.

PubMed

Lewis, Roger J; Connor, Jason T; Teerlink, John R; Murphy, James R; Cooper, Leslie T; Hiatt, William R; Brass, Eric P

2011-05-25

Claudication secondary to peripheral artery disease (PAD) is associated with substantial functional impairment. Phosphodiesterase (PDE) inhibitors have been shown to increase walking performance in these patients. K-134 is a selective PDE 3 inhibitor being developed as a potential treatment for claudication. The use of K-134, as with other PDE 3 inhibitors, in patients with PAD raises important safety and tolerability concerns, including the induction of cardiac ischemia, tachycardia, and hypotension. We describe the design, oversight, and implementation of an adaptive, phase II, dose-finding trial evaluating K-134 for the treatment of stable, intermittent claudication. The study design was a double-blind, multi-dose (25 mg, 50 mg, and 100 mg of K-134), randomized trial with both placebo and active comparator arms conducted in the United States and Russia. The primary objective of the study was to compare the highest tolerable dose of K-134 versus placebo using peak walking time after 26 weeks of therapy as the primary outcome. Study visits with intensive safety assessments were included early in the study period to provide data for adaptive decision making. The trial used an adaptive, dose-finding strategy to efficiently identify the highest dose(s) most likely to be safe and well tolerated, based on the side effect profiles observed within the trial, so that less promising doses could be abandoned. Protocol specified criteria for safety and tolerability endpoints were used and modeled prior to the adaptive decision making. The maximum target sample size was 85 subjects in each of the retained treatment arms. When 199 subjects had been randomized and 28-day data were available from 143, the Data Monitoring Committee (DMC) recommended termination of the lowest dose (25 mg) treatment arm. Safety evaluations performed during 14- and 28-day visits which included in-clinic dosing and assessments at peak drug concentrations provided core data for the DMC review. At the time of review, no subject in any of the five treatment arms (placebo, three K-134-containing arms, and cilostazol) had met pre-specified definitions for resting tachycardia or ischemic changes on exercise ECG. If, instead of dropping the 25-mg K-134 treatment arm, all arms had been continued to full enrollment, then approximately 43 additional research subjects would have been required to complete the trial. In this phase II, dose-finding trial of K-134 in the treatment of stable intermittent claudication, no concerning safety signals were seen at interim analysis, allowing the discontinuation of the lowest-dose-containing arm and the retention of the two highest-dose-containing arms. The adaptive design facilitated safe and efficient evaluation of K-134 in this high-risk cardiovascular population. ClinicalTrials.gov: NCT00783081.

Measurement of absolute gravity acceleration in Firenze

NASA Astrophysics Data System (ADS)

de Angelis, M.; Greco, F.; Pistorio, A.; Poli, N.; Prevedelli, M.; Saccorotti, G.; Sorrentino, F.; Tino, G. M.

2011-01-01

This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the University of Firenze (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the Newtonian law at short distances are in progress. Both experiments require an independent knowledge on the local value of g. The only available datum, pertaining to the italian zero-order gravity network, was taken more than 20 years ago at a distance of more than 60 km from the study site. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are (980 492 160.6 ± 4.0) μGal and (980 492 048.3 ± 3.0) μGal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

Peripheral artery bypass - leg

MedlinePlus

... nih.gov/pubmed/23473760 . Society for Vascular Surgery Lower Extremity Guidelines Writing Group; Conte MS, Pomposelli FB, et ... practice guidelines for atherosclerotic occlusive disease of the ... management of asymptomatic disease and claudication. J Vasc ...

COPART Risk Score, Endothelial Dysfunction, and Arterial Hypertension are Independent Risk Factors for Mortality in Claudicants.

PubMed

Hackl, G; Jud, P; Avian, A; Gary, T; Deutschmann, H; Seinost, G; Brodmann, M; Hafner, F

2016-08-01

The COPART risk score consists of six variables to assess the prognosis of PAOD patients. The flow mediated dilation (FMD) quantifies endothelial function. The aim of this study was to evaluate the mortality prediction of these two variables in a long-term observation of claudicants. 184 consecutive claudicants were included in a prospective observational study over a median observation period of 7.9 (IQR 7.2-8.7) years. The endothelial function was assessed on the day of study inclusion using brachial FMD. Three groups were assigned according to the COPART risk score: low risk (LR), n = 72 (39%); medium risk (MR), n = 59 (32%); and high risk (HR), n = 53 (29%). Overall survival rates differed among COPART risk score groups (p < .001, 5 year survival: LR group 83% [95% CI 74-92%]; MR group 73% [95% CI 62-84%]; HR group 57% [95% CI 43-70%]). Survivors had a significantly better median FMD than non-survivors (4.1% [IQR 1.2-6.4] vs. 1.3% [IQR 0.0-4.2]; p < .001). Also the FMD differed significantly among the three COPART risk groups (LR 4.0% [IQR 1.2-6.3], MR 2.3% [IQR 0.0-6.3], HR 1.7% [IQR 0.0-3.6]; p = .033). Finally, independent predictors for disease specific survival were COPART risk score (p = .033; MR group [HR 1.6], 95% CI 0.7-3.6; HR group [HR 2.7], 95% CI 1.2-5.8), FMD (p = .004; FMD ≤2.5 vs. >2.5, HR 2.6, 95% CI 1.4-4.9), and arterial hypertension (p = .039; HR 3.5, 95% CI 1.1-11.3). COPART risk score, FMD, and arterial hypertension are independent long-term mortality predictors in this group of claudicants. The best mortality assessment is provided by including all three predictors. Copyright © 2016 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Home-based exercise for elderly patients with intermittent claudication limited by osteoarticular disorders - feasibility and effectiveness of a low-intensity programme.

PubMed

Lamberti, Nicola; Straudi, Sofia; Lissia, Efisio; Cavazzini, Lorenza; Buja, Sergio; Manfredini, Roberto; Basaglia, Nino; Manfredini, Fabio

2018-04-01

Peripheral arterial disease (PAD) is a common cardiovascular pathology affecting mobility in elderly. Osteoarticular diseases (ODs), responsible for functional limitations and confounding leg symptoms, may interfere with exercise therapy. This study evaluates the feasibility and effectiveness of a structured home-based exercise programme on rehabilitative outcomes in a cohort of elderly PAD patients with and without coexisting ODs. Patients were enrolled from 2002 to 2016 in an exercise programme prescribed and controlled at the hospital and based on two daily 10-minute home walking sessions below the self-selected speed. The presence and localization of ODs at baseline were derived from consultation of medical documents. The ankle-brachial index and functional outcomes, defined as speed at the onset of claudication and attainable maximal speed by an incremental treadmill test, were assessed at baseline and discharge. Feasibility was determined according to dropout rate, number of visits, duration of the programme, and adherence. A total of 1,251 PAD patients were enrolled (931 men; 71 ± 9 years; 0.63 ± 0.19 ankle-brachial index). Eight hundred sixty-four patients were free of ODs (ODfree PAD , 69 %), whereas 387 were affected by ODs (OD PAD , 31 %), predominantly located in the spine (72 %). In the logistic regression models, the presence of ODs was associated with female sex, overweight, sedentary and/or driving professions. At discharge, OD PAD and ODfree PAD did not differ in dropout rates (12 % each), programme duration (378 ± 241 vs. 390 ± 260 days), number of visits (7 ± 3 each), and adherence (80 % each). Similar improvements for OD PAD and ODfree PAD were observed for the ankle-brachial index (0.06 ± 0.12 each), the speed at onset of claudication (0.7 ± 0.7 vs. 0.7 ± 0.8 kmh-1; p = 0.70), and maximal speed (0.4 ± 0.6 vs. 0.4 ± 0.6 kmh-1; p = 0.77). Equally satisfactory rehabilitative outcomes were observed in elderly patients with claudication limited by ODs who completed a well-tolerated, low-impact structured exercise programme.

76 FR 61599 - Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for the Marbled Murrelet

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-05

..., which suggests that forest type influences murrelet occurrence, rather than absolute distance from the... zone, and not the distance from the coast. This is probably due to the maritime climate that provides... hotter, drier climate. This rapid transition to less favorable conditions for murrelets may explain why...

3D interferometric shape measurement technique using coherent fiber bundles

NASA Astrophysics Data System (ADS)

Zhang, Hao; Kuschmierz, Robert; Czarske, Jürgen

2017-06-01

In-situ 3-D shape measurements with submicron shape uncertainty of fast rotating objects in a cutting lathe are expected, which can be achieved by simultaneous distance and velocity measurements. Conventional tactile methods, coordinate measurement machines, only support ex-situ measurements. Optical measurement techniques such as triangulation and conoscopic holography offer only the distance, so that the absolute diameter cannot be retrieved directly. In comparison, laser Doppler distance sensors (P-LDD sensor) enable simultaneous and in-situ distance and velocity measurements for monitoring the cutting process in a lathe. In order to achieve shape measurement uncertainties below 1 μm, a P-LDD sensor with a dual camera based scattered light detection has been investigated. Coherent fiber bundles (CFB) are employed to forward the scattered light towards cameras. This enables a compact and passive sensor head in the future. Compared with a photo detector based sensor, the dual camera based sensor allows to decrease the measurement uncertainty by the order of one magnitude. As a result, the total shape uncertainty of absolute 3-D shape measurements can be reduced to about 100 nm.

Distance and absolute magnitudes of the brightest stars in the dwarf galaxy Sextans A

NASA Technical Reports Server (NTRS)

Sandage, A.; Carlson, G.

1982-01-01

In an attempt to improve present bright star calibration, data were gathered for the brightest red and blue stars and the Cepheids in the Im V dwarf galaxy, Sextans A. On the basis of a magnitude sequence measured to V and B values of about 22 and 23, respectively, the mean magnitudes of the three brightest blue stars are V=17.98 and B=17.88. The three brightest red supergiants have V=18.09 and B=20.14. The periods and magnitudes measured for five Cepheids yield an apparent blue distance modulus of 25.67 + or - 0.2, via the P-L relation, and the mean absolute magnitudes of V=-7.56 and B=-5.53 for the red supergiants provide additional calibration of the brightest red stars as distance indicators. If Sextans A were placed at the distance of the Virgo cluster, it would appear to have a surface brightness of 23.5 mag/sq arcec. This, together with the large angular diameter, would make such a galaxy easily discoverable in the Virgo cluster by means of ground-based surveys.

Absolute proper motion of IRAS 00259+5625 with VERA: Indication of superbubble expansion motion

NASA Astrophysics Data System (ADS)

Sakai, Nobuyuki; Sato, Mayumi; Motogi, Kazuhito; Nagayama, Takumi; Shibata, Katsunori M.; Kanaguchi, Masahiro; Honma, Mareki

2014-02-01

We present the first measurement of the absolute proper motions of IRAS 00259+5625 (CB3, LBN594) associated with the H I loop called the "NGC 281 superbubble" that extends from the Galactic plane over ˜ 300 pc toward decreasing galactic latitude. The proper motion components measured with VLBI Exploration of Radio Astrometry (VERA) are (μαcos δ, μδ) = (-2.48 ± 0.32, -2.85 ± 0.65) mas yr-1, converted into (μlcos b, μb) = (-2.72 ± 0.32, -2.62 ± 0.65) mas yr-1 in the Galactic coordinates. The measured proper motion perpendicular to the Galactic plane (μb) shows vertical motion away from the Galactic plane with a significance of about ˜ 4 σ. As for the source distance, the distance measured with VERA is marginal, 2.4^{+1.0}_{-0.6} kpc. Using the distance, an absolute vertical motion (vb) of -17.9 ± 12.2 km s-1 is determined with ˜ 1.5 σ significance. The tendency towards the large vertical motion is consistent with previous very long baseline interferometry (VLBI) results for NGC 281 associated with the same superbubble. Thus, our VLBI results indicate superbubble expansion motion whose origin is believed to be sequential supernova explosions.

Bias Properties of Extragalactic Distance Indicators. VIII. H0 from Distance-limited Luminosity Class and Morphological Type-Specific Luminosity Functions for SB, SBC, and SC Galaxies Calibrated Using Cepheids

NASA Astrophysics Data System (ADS)

Sandage, Allan

1999-12-01

Relative, reduced to absolute, magnitude distributions are obtained for Sb, Sbc, and Sc galaxies in the flux-limited Revised Shapley-Ames Catalog (RSA2) for each van den Bergh luminosity class (L), within each Hubble type (T). The method to isolate bias-free subsets of the total sample is via Spaenhauer diagrams, as in previous papers of this series. The distance-limited type and class-specific luminosity functions are normalized to numbers of galaxies per unit volume (105 Mpc3), rather than being left as relative functions, as in Paper V. The functions are calculated using kinematic absolute magnitudes, based on an arbitrary trial value of H0=50. Gaussian fits to the individual normalized functions are listed for each T and L subclass. As in Paper V, the data can be freed from the T and L dependencies by applying a correction of 0.23T+0.5L to the individual absolute magnitudes. Here, T=3 for Sb, 4 for Sbc, and 5 for Sc galaxies, and the L values range from 1 to 6 as the luminosity class changes from I to III-IV. The total luminosity function, obtained by combining the volume-normalized Sb, Sbc, and Sc individual luminosity functions, each corrected for the T and L dependencies, has an rms dispersion of 0.67 mag, similar to much of the Tully-Fisher parameter space. Absolute calibration of the trial kinematic absolute magnitudes is made using 27 galaxies with known T and L that also have Cepheid distances. This permits the systematic correction to the H0=50 kinematic absolute magnitudes of 0.22+/-0.12 mag, givingH0=55+/-3(internal) km s-1 Mpc-1 . The Cepheid distances are based on the Madore/Freedman Cepheid period-luminosity (PL) zero point that requires (m-M)0=18.50 for the LMC. Using the modern LMC modulus of (m-M)0=18.58 requires a 4% decrease in H0, giving a final value of H0=53+/-7 (external) by this method. These values of H0, based here on the method of luminosity functions, are in good agreement with (1) H0=55+/-5 by Theureau and coworkers from their bias-corrected Tully-Fisher method of ``normalized distances'' for field galaxies; (2) H0=56+/-4 from the method through the Virgo Cluster, as corrected to the global kinematic frame (Tammann and coworkers); and (3) H0=58+/-5 from Cepheid-calibrated Type Ia supernovae (Saha and coworkers). Our value here also disagrees with the final value from the NASA ``Key Project'' group value of H0=70+/-7. Analysis of the total flux-limited sample of Sb, Sbc, and Sc galaxies in the RSA2 by the present method, but uncorrected for selection bias, would give an incorrect value of H0=71 using the same Cepheid calibration. The effect of the bias is pernicious at the 30% level; either it must be corrected by the methods in the papers of this series, or the data must be restricted to the distance-limited subset of any sample, as is done here.

Income and Social Rank Influence UK Children's Behavioral Problems: A Longitudinal Analysis.

PubMed

Garratt, Elisabeth A; Chandola, Tarani; Purdam, Kingsley; Wood, Alex M

2017-07-01

Children living in low-income households face elevated risks of behavioral problems, but the impact of absolute and relative income to this risk remains unexplored. Using the U.K. Millennium Cohort Study data, longitudinal associations between Strengths and Difficulties Questionnaire scores and absolute household income, distance from the regional median and mean income, and regional income rank were examined in 3- to 12-year-olds (n = 16,532). Higher absolute household incomes were associated with lower behavioral problems, while higher income rank was associated with lower behavioral problems only at the highest absolute incomes. Higher absolute household incomes were associated with lower behavioral problems among children in working households, indicating compounding effects of income and socioeconomic advantages. Both absolute and relative incomes therefore appear to influence behavioral problems. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.

Peripheral Arterial Disease and Claudication

MedlinePlus

... Mental Health Sex and Birth Control Sex and Sexuality Birth Control Family Health Infants and Toddlers Kids ... Mental Health Sex and Birth Control Sex and Sexuality Birth Control Family Health Infants and Toddlers Kids ...

Does Medial Meniscal Allograft Transplantation With the Bone-Plug Technique Restore the Anatomic Location of the Native Medial Meniscus?

PubMed

Kim, Nam-Ki; Bin, Seong-Il; Kim, Jong-Min; Lee, Chang-Rack

2015-12-01

Previous work has shown the importance of restoring the normal structure of the native meniscus with meniscal allograft transplantation. The purpose of this study was to compare the anatomic positions of the anterior horn and posterior horn between the preoperative medial meniscus and the postoperative meniscal allograft after medial meniscal allograft transplantation with the bone-plug technique. The hypothesis was that the bone-plug technique could restore the preoperative structure of the native medial meniscus. Case series; Level of evidence, 4. Between December 1999 and December 2013, a total of 59 patients (49 male, 10 female) underwent medial meniscal allograft transplantation by use of the bone-plug technique. The anatomic positions of both horns in the native medial meniscus and in the meniscal allograft were measured via MRI. The percentage reference method was used to measure the locations of both horns. On coronal MRI, the mean absolute distance of the posterior horn from the lateral border of the tibial plateau changed from 45.2 ± 3.3 to 48.1 ± 4.2 mm (P < .05), and the percentage distance of the posterior horn changed from 59.6% to 63.0% (P < .05). On sagittal MRI, the mean absolute distance of the posterior horn from the anterior reference point changed from 40.3 ± 3.0 to 42.0 ± 3.5 mm (P < .05), and the mean percentage distance of the posterior horn changed from 76.5% to 79.4% (P <.05). On coronal MRI, the mean absolute distance of the anterior horn from the lateral border of the tibial plateau changed from 41.3 ± 4.2 to 48.5 ± 5.6 mm (P < .05), and the mean percentage distance of the anterior horn changed from 54.5% to 63.8% (P < .05). On sagittal MRI, the mean absolute distance of the anterior horn from the anterior reference point changed from 5.5 ± 1.0 to 9.9 ± 2.9 mm (P < .05), and the mean percentage distance of the anterior horn changed from 10.6% to 19.0% (P < .05). Despite attempts to place the meniscal allograft in the same position as the native meniscus, the anatomic locations of both horns were shifted posteromedially compared with those of the native medial meniscus. There were significant differences, attributed to several limitations in the bone-plug technique, between the preoperative and postoperative values of both horns. However, the posterior horn showed a location change of <5 mm, on average, in both the coronal and sagittal planes, whereas the anterior horn showed a location change of ≥ 5 mm in the coronal plane but <5 mm in the sagittal plane. © 2015 The Author(s).

Patient and Provider Assessment of Lipid Management Registry

ClinicalTrials.gov

2016-02-15

Hyperlipidemia; Hypercholesterolemia; Cardiovascular Disease; Diabetes; Chronic Kidney Disease (CKD); Hypertension; Smoking; Myocardial Infarction (MI); Unstable Angina; Angina; Coronary Artery Disease (CAD); Stroke; Transient Ischemic Attack (TIA); Carotid Stenosis; Peripheral Arterial Disease; Atherosclerosis; Claudication

Estimated metabolic and mechanical demands during different small-sided games in elite soccer players.

PubMed

Gaudino, Paolo; Alberti, Giampietro; Iaia, F Marcello

2014-08-01

The present study examined the extent to which game format (possession play, SSG-P and game with regular goals and goalkeepers, SSG-G) and the number of players (5, 7 and 10 a-side) influence the physical demands of small-sided soccer games (SSGs) in elite soccer players. Training data were collected during the in-season period from 26 English Premier League outfield players using global positioning system technology. Total distance covered, distance at different speed categories and maximal speed were calculated. In addition, we focused on changes in velocity by reporting the number of accelerations and decelerations carried out during the SSGs (divided in two categories: moderate and high) and the absolute maximal values of acceleration and deceleration achieved. By taking into account these parameters besides speed and distance values, estimated energy expenditure and average metabolic power and distance covered at different metabolic power categories were calculated. All variables were normalized by time (i.e., 4min). The main findings were that the total distance, distances run at high speed (>14.4kmh(-1)) as well as absolute maximum velocity, maximum acceleration and maximum deceleration increased with pitch size (10v10>7v7>5v5; p<.05). Furthermore, total distance, very high (19.8-25.2kmh(-1)) and maximal (>25.2kmh(-1)) speed distances, absolute maximal velocity and maximum acceleration and deceleration were higher in SSG-G than in SSG-P (p<.001). On the other hand, the number of moderate (2-3ms(-2)) accelerations and decelerations as well as the total number of changes in velocity were greater as the pitch dimensions decreased (i.e., 5v5>7v7>10v10; p<.001) in both SSG-G and SSG-P. In addition, predicted energy cost, average metabolic power and distance covered at every metabolic power categories were higher in SSG-P compared to SSG-G and in big than in small pitch areas (p<.05). A detailed analysis of these drills is pivotal in contemporary football as it enables an in depth understanding of the workload imposed on each player which consequently has practical implications for the prescription of the adequate type and amount of stimulus during exercise training. Copyright © 2014 Elsevier B.V. All rights reserved.

Sub-nanometer periodic nonlinearity error in absolute distance interferometers

NASA Astrophysics Data System (ADS)

Yang, Hongxing; Huang, Kaiqi; Hu, Pengcheng; Zhu, Pengfei; Tan, Jiubin; Fan, Zhigang

2015-05-01

Periodic nonlinearity which can result in error in nanometer scale has become a main problem limiting the absolute distance measurement accuracy. In order to eliminate this error, a new integrated interferometer with non-polarizing beam splitter is developed. This leads to disappearing of the frequency and/or polarization mixing. Furthermore, a strict requirement on the laser source polarization is highly reduced. By combining retro-reflector and angel prism, reference and measuring beams can be spatially separated, and therefore, their optical paths are not overlapped. So, the main cause of the periodic nonlinearity error, i.e., the frequency and/or polarization mixing and leakage of beam, is eliminated. Experimental results indicate that the periodic phase error is kept within 0.0018°.

The Relationship between Running Economy and Biomechanical Variables in Distance Runners

ERIC Educational Resources Information Center

Tartaruga, Marcus Peikriszwili; Brisswalter, Jeanick; Peyre-Tartaruga, Leonardo Alexandre; Avila, Aluisio Otavio Vargas; Alberton, Cristine Lima; Coertjens, Marcelo; Cadore, Eduardo Lusa; Tiggemann, Carlos Leandro; Silva, Eduardo Marczwski; Kruel, Luiz Fernando Martins

2012-01-01

In this study, we analyzed the relationship between running economy (RE) and biomechanical parameters in a group running at the same relative intensity and same absolute velocity. Sixteen homogeneous male long-distance runners performed a test to determine RE at 4.4 m.s[superscript -1], corresponding to 11.1% below velocity at the ventilatory…

Using Google Earth to Teach the Magnitude of Deep Time

ERIC Educational Resources Information Center

Parker, Joel D.

2011-01-01

Most timeline analogies of geologic and evolutionary time are fundamentally flawed. They trade off the problem of grasping very long times for the problem of grasping very short distances. The result is an understanding of relative time with little comprehension of absolute time. Earlier work has shown that the distances most easily understood by…

Tachistoscopic exposure and masking of real three-dimensional scenes

PubMed Central

Pothier, Stephen; Philbeck, John; Chichka, David; Gajewski, Daniel A.

2010-01-01

Although there are many well-known forms of visual cues specifying absolute and relative distance, little is known about how visual space perception develops at small temporal scales. How much time does the visual system require to extract the information in the various absolute and relative distance cues? In this article, we describe a system that may be used to address this issue by presenting brief exposures of real, three-dimensional scenes, followed by a masking stimulus. The system is composed of an electronic shutter (a liquid crystal smart window) for exposing the stimulus scene, and a liquid crystal projector coupled with an electromechanical shutter for presenting the masking stimulus. This system can be used in both full- and reduced-cue viewing conditions, under monocular and binocular viewing, and at distances limited only by the testing space. We describe a configuration that may be used for studying the microgenesis of visual space perception in the context of visually directed walking. PMID:19182129

Intensive walking exercise for lower extremity peripheral arterial disease: A systematic review and meta-analysis.

PubMed

Lyu, Xiafei; Li, Sheyu; Peng, Shifeng; Cai, Huimin; Liu, Guanjian; Ran, Xingwu

2016-05-01

Supervised treadmill exercise is the recommended therapy for peripheral arterial disease (PAD) patients with intermittent claudication (IC). However, most PAD patients do not exhibit typical symptoms of IC. The aim of the present study was to explore the efficacy and safety of intensive walking exercise in PAD patients with and without IC. The PubMed, Embase and Cochrane Library databases were systematically searched. Randomized controlled trials comparing the effects of intensive walking exercise with usual care in patients with PAD were included for systematic review and meta-analysis. Eighteen trials with 1200 patients were eligible for the present analysis. Compared with usual care, intensive walking exercise significantly improved the maximal walking distance (MWD), pain-free walking distance, and the 6-min walking distance in patients with PAD (P < 0.00001 for all). Subgroup analyses indicated that a lesser improvement in MWD was observed in the subgroup with more diabetes patients, and that the subgroup with better baseline walking ability exhibited greater improvement in walking performance. In addition, similar improvements in walking performance were observed for exercise programs of different durations and modalities. No significant difference was found in adverse events between the intensive walking and usual care groups (relative risk 0.84; 95% confidence interval 0.51, 1.39; P = 0.50). Regardless of exercise length and modality, regularly intensive walking exercise improves walking ability in PAD patients more than usual care. The presence of diabetes may attenuate the improvements in walking performance in patients with PAD following exercise. © 2015 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

A novel validation and calibration method for motion capture systems based on micro-triangulation.

PubMed

Nagymáté, Gergely; Tuchband, Tamás; Kiss, Rita M

2018-06-06

Motion capture systems are widely used to measure human kinematics. Nevertheless, users must consider system errors when evaluating their results. Most validation techniques for these systems are based on relative distance and displacement measurements. In contrast, our study aimed to analyse the absolute volume accuracy of optical motion capture systems by means of engineering surveying reference measurement of the marker coordinates (uncertainty: 0.75 mm). The method is exemplified on an 18 camera OptiTrack Flex13 motion capture system. The absolute accuracy was defined by the root mean square error (RMSE) between the coordinates measured by the camera system and by engineering surveying (micro-triangulation). The original RMSE of 1.82 mm due to scaling error was managed to be reduced to 0.77 mm while the correlation of errors to their distance from the origin reduced from 0.855 to 0.209. A simply feasible but less accurate absolute accuracy compensation method using tape measure on large distances was also tested, which resulted in similar scaling compensation compared to the surveying method or direct wand size compensation by a high precision 3D scanner. The presented validation methods can be less precise in some respects as compared to previous techniques, but they address an error type, which has not been and cannot be studied with the previous validation methods. Copyright © 2018 Elsevier Ltd. All rights reserved.

Endofibrosis of Iliac Arteries in High-Performance Athletes: Diagnostic Approach and Minimally Invasive Endovascular Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giannoukas, Athanasios D., E-mail: agiannoukas@hotmail.com; Berczi, Viktor; Anoop, Unnikrishnan

The aim of this article is to report our experience in the diagnosis of two cases of iliac artery endofibrosis or arteriopathy, a rare entity occurring in high-performance athletes, presenting with intermittent claudication (right-sided in both) after maximal exercise. External iliac artery endofibrosis or arteriopathy is a likely diagnosis in competitive athletes free of cardiovascular risk factors who present with leg claudication. Arteriography and a papaverine-assisted mean pressure gradient across the iliac arteries of more than 10 mmHg is a useful diagnostic approach. Moreover, balloon angioplasty of the iliac artery in that patient, in whom a pressure gradient was detected,more » resulted in symptomatic relief for 2 months followed by mild symptom recurrence. Thus, although balloon angioplasty is feasible and safe, it might not be adequate to treat this entity and, thus, its value remains undefined.« less

The physical and psychological impact of neurogenic claudication: the patients' perspectives.

PubMed

Ammendolia, Carlo; Schneider, Michael; Williams, Kelly; Zickmund, Susan; Hamm, Megan; Stuber, Kent; Tomkins-Lane, Christy; Rampersaud, Y Raja

2017-03-01

The patient perspective regarding the impact of neurogenic claudication (NC) has not been well studied. The objectives of this study were to determine what is most bothersome among patients with NC and how it impacts their lives and expectations with surgical and non-surgical treatment. Semi-structured telephone interviews were conducted, audio recorded and transcribed verbatim. A thematic analysis categorized key findings based on relative importance and impact on participants. Twenty-eight individuals participated in this study. Participants were most bothered by the pain of NC, which dramatically impacted their lives. Inability to walk was the dominant functional limitation and this impacted the ability to engage in recreational and social activities. The most surprising finding was how frequently participants reported significant emotional effects of NC. From a patients' perspective NC has a significant multidimensional effects with pain, limited walking ability and emotional effects being most impactful to their lives.

[The modern principles of management of intermittent claudication].

PubMed

Gamzatov, T H; Svetlikov, A V

2016-01-01

Number of patients with peripheral arterial disease, despite various national public health programs, remains high and has no steady downward trend over the past few decades. Despite recent advances in drug therapy, сonservative approach in the management of peripheral arterial disease is often neglected by vascular surgeons. However, vast majority of patients with intermittent claudication, who receive comprehensive conservative treatment, including risk factor modification, exercise and drug therapy, may get significant improvement in quality of life by partial or complete relief of symptoms related to the disease. Patients strictly adhering to medical recommendations has favorable prognosis and progression of disease to the stage of critical limb ischemia is very unlikely. Noncompliant patients and those who continue smoking in particular, often experience progression of symptoms related to the disease. That may result in the need for surgical intervention aiming to prevent or delay the onset of critical limb ischemia.

Distance Estimation Using Handheld Devices

DTIC Science & Technology

2013-06-01

each and all centered in the pin that marks the location of the device. ................................47 Figure 21. Form interface where the UFO ...SIFT Scale-invariant feature transform SURF Speed up Robust Features SAD Sum of Absolute Distance UFOs Untrained Forward Observers WHATWG Web...Forward Observers ( UFOs ) to make a successful call for fire. This chapter presents the solution from different aspects and is organized as follows

File Carving and Malware Identification Algorithms Applied to Firmware Reverse Engineering

DTIC Science & Technology

2013-03-21

33 3.5 Performance Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.6 Experimental...consider a byte value rate-of-change frequency metric [32]. Their system calculates the absolute value of the distance between all consecutive bytes, then...the rate-of-change means and standard deviations. Karresand and Shahmehri use the same distance metric for both byte value frequency and rate-of-change

Double-sideband frequency scanning interferometry for long-distance dynamic absolute measurement

NASA Astrophysics Data System (ADS)

Mo, Di; Wang, Ran; Li, Guang-zuo; Wang, Ning; Zhang, Ke-shu; Wu, Yi-rong

2017-11-01

Absolute distance measurements can be achieved by frequency scanning interferometry which uses a tunable laser. The main drawback of this method is that it is extremely sensitive to the movement of targets. In addition, since this method is limited to the linearity of frequency scanning, it is commonly used for close measurements within tens of meters. In order to solve these problems, a double-sideband frequency scanning interferometry system is presented in the paper. It generates two opposite frequency scanning signals through a fixed frequency laser and a Mach-Zehnder modulator. And the system distinguishes the two interference fringe patterns corresponding to the two signals by IQ demodulation (i.e., quadrature detection) of the echo. According to the principle of double-sideband modulation, the two signals have the same characteristics. Therefore, the error caused by the target movement can be effectively eliminated, which is similar to dual-laser frequency scanned interferometry. In addition, this method avoids the contradiction between laser frequency stability and swept performance. The system can be applied to measure the distance of the order of kilometers, which profits from the good linearity of frequency scanning. In the experiment, a precision about 3 μm was achieved for a kilometer-level distance.

Using Blur to Affect Perceived Distance and Size

PubMed Central

HELD, ROBERT T.; COOPER, EMILY A.; O’BRIEN, JAMES F.; BANKS, MARTIN S.

2011-01-01

We present a probabilistic model of how viewers may use defocus blur in conjunction with other pictorial cues to estimate the absolute distances to objects in a scene. Our model explains how the pattern of blur in an image together with relative depth cues indicates the apparent scale of the image’s contents. From the model, we develop a semiautomated algorithm that applies blur to a sharply rendered image and thereby changes the apparent distance and scale of the scene’s contents. To examine the correspondence between the model/algorithm and actual viewer experience, we conducted an experiment with human viewers and compared their estimates of absolute distance to the model’s predictions. We did this for images with geometrically correct blur due to defocus and for images with commonly used approximations to the correct blur. The agreement between the experimental data and model predictions was excellent. The model predicts that some approximations should work well and that others should not. Human viewers responded to the various types of blur in much the way the model predicts. The model and algorithm allow one to manipulate blur precisely and to achieve the desired perceived scale efficiently. PMID:21552429

Status of use of lunar irradiance for on-orbit calibration

USGS Publications Warehouse

Stone, T.C.; Kieffer, H.H.; Anderson, J.M.; ,

2002-01-01

Routine observations of the Moon have been acquired by the Robotic Lunar Observatory (ROLO) for over four years. The ROLO instruments measure lunar radiance in 23 VNIR (Moon diameter ???500 pixels) and 9 SWIR (???250 pixels) passbands every month when the Moon is at phase angle less than 90 degrees. These are converted to exoatmospheric values at standard distances using an atmospheric extinction model based on observations of standard stars and a NIST-traceable absolute calibration source. Reduction of the stellar images also provides an independent pathway for absolute calibration. Comparison of stellar-based and lamp-based absolute calibrations of the lunar images currently shows unacceptably large differences. An analytic model of lunar irradiance as a function of phase angle and viewing geometry is derived from the calibrated lunar images. Residuals from models which fit hundreds of observations at each wavelength average less than 2%. Comparison with SeaWiFS observations over three years reveals a small quasi-periodic change in SeaWiFS responsivity that correlates with distance from the Sun for the first two years, then departs from this correlation.

Anatomic motor point localization for partial quadriceps block in spasticity.

PubMed

Albert, T; Yelnik, A; Colle, F; Bonan, I; Lassau, J P

2000-03-01

To identify the location of the vastus intermedius nerve and its motor point (point M) and to precisely identify its coordinates in relation to anatomic surface landmarks. Descriptive study. Anatomy institute of a university school of medicine. Twenty-nine adult cadaver limbs immobilized in anatomic position. Anatomic dissection to identify point M. Anatomic surface landmarks were point F, the issuing point of femoral nerve under the inguinal ligament; point R, the middle of superior edge of the patella; segment FR, which corresponds to thigh length; point M', point M orthogonal projection on segment FR. Absolute vertical coordinate, distance FM, relative vertical coordinate compared to the thigh length, FM'/FR ratio; absolute horizontal coordinate, distance MM'. The absolute vertical coordinate was 11.7+/-2 cm. The relative vertical coordinate was at .29+/-.04 of thigh length. The horizontal coordinate was at 2+/-.5 cm lateral to the FR line. Point M can be defined with relative precision by two coordinates. Application and clinical interest of nerve blocking using these coordinates in quadriceps spasticity should be studied.

Complementary therapies for peripheral arterial disease: systematic review.

PubMed

Pittler, Max H; Ernst, Edzard

2005-07-01

While peripheral arterial disease (PAD) affects a considerable proportion of patients in the primary care setting, there is a high level of use of complementary treatment options. The aim was to assess the effectiveness of any type of complementary therapy for peripheral arterial disease. A systematic review was performed. Literature searches were conducted on Medline, Embase, Amed, and the Cochrane Library until December 2004. Hand-searches of medical journals and bibliographies were conducted. There were no restrictions regarding the language of publication. The screening of studies, selection, data extraction, the assessment of methodologic quality and validation were performed independently by the two reviewers. Data from randomized controlled trials, and systematic reviews and meta-analyses, which based their findings on the results of randomized controlled trials were included. Seven systematic reviews and meta-analyses and three additional randomized controlled trials met the inclusion criteria and were reviewed. The evidence relates to acupuncture, biofeedback, chelation therapy, CO(2)-applications and the dietary supplements Allium sativum (garlic), Ginkgo biloba (ginkgo), omega-3 fatty acids, padma 28 and Vitamin E. Most studies included only patients with peripheral arterial disease in Fontaine stage II (intermittent claudication). The reviewed RCTs, systematic reviews and meta-analyses which based their findings on the results of RCTs suggest that G. biloba is effective compared with placebo for patients with intermittent claudication. Evidence also suggests that padma 28 is effective for intermittent claudication, although more data are required to confirm these findings. For all other complementary treatment options there is no evidence beyond reasonable doubt to suggest effectiveness for patients with peripheral arterial disease.

Effectiveness of interspinous implant surgery in patients with intermittent neurogenic claudication: a systematic review and meta-analysis.

PubMed

Moojen, Wouter A; Arts, Mark P; Bartels, Ronald H M A; Jacobs, Wilco C H; Peul, Wilco C

2011-10-01

Despite an increasing implantation rate of interspinous process distraction (IPD) devices in the treatment of intermittent neurogenic claudication (INC), definitive evidence on the clinical effectiveness of implants is lacking. The main objective of this review was to perform a meta-analysis of all systematic reviews, randomized clinical trials and prospective cohort series to quantify the effectiveness of IPDs and to evaluate the potential side-effects. Data from all studies prospectively describing clinical results based on validated outcome scales and reporting complications of treatment of patients with INC with IPD placement. We searched MEDLINE, EMBASE, Web of Science, Cochrane (CENTRAL), CINAHL, Academic Search Premier, Science Direct up to July 2010. Studies describing patients with INC caused by lumbar stenosis, reporting complication rate and reporting based on validated outcome scores, were eligible. Studies with only instrumented IPD results were excluded. Eleven studies eligible studies were identified. Two independently RCTs and eight prospective cohorts were available. In total 563 patients were treated with IPDs. All studies showed improvement in validated outcome scores after 6 weeks and 1 year. Pooled data based on the Zurich Claudication Questionnaire of the RCTs were more in favor of IPD treatment compared with conservative treatment (pooled estimate 23.2, SD 18.5-27.8). Statistical heterogeneity after pooled data was low (I-squared 0.0, p = 0.930). Overall complication rate was 7%. As the evidence is relatively low and the costs are high, more thorough (cost-) effectiveness studies should be performed before worldwide implementation is introduced.

Pacing and Performance in Competitive Middle-Distance Speed Skating

ERIC Educational Resources Information Center

Muehlbauer, Thomas; Schindler, Christian; Panzer, Stefan

2010-01-01

Data from speed skating during World Cup 1,500-m middle-distance races were analyzed to (a) determine the time/velocity distribution during the race and (b) assess the impact of time spent in several race sectors on performance outcome. Absolute and relative sector times for the first 300 m (S1) and the following three 400-m laps (S2-S4) and their…

UBV Photometry of Selected Eclipsing Binaries in the Magellanic Clouds.

NASA Astrophysics Data System (ADS)

Davidge, Timothy John

1987-12-01

UBV photoelectric observations of five eclipsing binaries in the Magellanic Clouds are presented and discussed in detail. The systems studied are HV162O and HV1669 in the Small Magellanic Cloud and HV2241, HV2765, and HV5943 in the Large Magellanic Cloud. Classification spectra indicate that the components of these systems are of spectral type late O or early B. The systems are located in moderately crowded areas. Therefore, CCD observations were used to construct models of the star fields around the variables. These were used to correct the photoelectric measurements for contamination. Light curve solutions were found with the Wilson -Devinney program. A two dimensional search of parameter space involving the mass ratio and the surface potential of the secondary component was employed. This procedure was tested by numerical simulation and was found to predict the light curve elements, including the mass ratios, within their estimated uncertainties. It appears likely that none of the systems are in contact, a surprising result considering the high frequency of early type contact binaries in the solar neighborhood. The light curve solutions were then used to compute the absolute dimensions of the components. Only one system, HV2241, has a radial velocity curve, allowing its absolute dimensions to be well established. Less accurate absolute dimensions were calculated for the remaining systems using photometric information. The components were then placed on H-R diagrams and compared with theoretical models of stellar evolution. The positions of the components on these diagrams appear to support the existence of convective core overshooting. The evolutionary status of the systems was also discussed. The system with the most accurately determined absolute dimensions, HV2241, appears to have undergone, or is nearing the end of, Case A mass transfer. Two other systems, HV1620 and HV1669, may also be involved in mass transfer. Finally, the use of eclipsing binaries as distance indicators was investigated. The distance modulus of the LMC was computed in two ways. One approach used the absolute dimensions found with the radial velocity data while the other employed the method of photometric parallaxes. The latter technique was also used to calculate the distance modulus of the SMC.

A new approach of the Star Excursion Balance Test to assess dynamic postural control in people complaining from chronic ankle instability.

PubMed

Pionnier, Raphaël; Découfour, Nicolas; Barbier, Franck; Popineau, Christophe; Simoneau-Buessinger, Emilie

2016-03-01

The purpose of this study was to quantitatively and qualitatively assess dynamic balance with accuracy in individuals with chronic ankle instability (CAI). To this aim, a motion capture system was used while participants performed the Star Excursion Balance Test (SEBT). Reached distances for the 8 points of the star were automatically computed, thereby excluding any dependence to the experimenter. In addition, new relevant variables were also computed, such as absolute time needed to reach each distance, lower limb ranges of motion during unipodal stance, as well as absolute error of pointing. Velocity of the center of pressure and range of variation of ground reaction forces have also been assessed during the unipodal phase of the SEBT thanks to force plates. CAI group exhibited smaller reached distances and greater absolute error of pointing than the control group (p<0.05). Moreover, the ranges of motion of lower limbs joints, the velocity of the center of pressure and the range of variation of the ground reaction forces were all significantly smaller in the CAI group (p<0.05). These reduced quantitative and qualitative performances highlighted a lower dynamic postural control. The limited body movements and accelerations during the unipodal stance in the CAI group could highlight a protective strategy. The present findings could help clinicians to better understand the motor strategies used by CAI patients during dynamic balance and may guide the rehabilitation process. Copyright © 2016 Elsevier B.V. All rights reserved.

The Effect of a 20 km Run on Appetite Regulation in Long Distance Runners

PubMed Central

Kojima, Chihiro; Ishibashi, Aya; Ebi, Kumiko; Goto, Kazushige

2016-01-01

The purpose of the present study was to investigate appetite-related hormonal responses and energy intake after a 20 km run in trained long distance runners. Twenty-three male long-distance runners completed two trials: either an exercise trial consisting of a 20 km outdoor run (EX) or a control trial with an identical period of rest (CON). Blood samples were collected to determine plasma acylated ghrelin, peptide YY3-36 (PYY3-36) and other hormonal and metabolite concentrations. Energy intake during a buffet test meal was also measured 30 min after the exercise or rest periods. Although plasma acylated ghrelin concentrations were significantly decreased after the 20 km run (p < 0.05), plasma PYY3-36 did not change significantly following exercise. Absolute energy intake during the buffet test meal in EX (1325 ± 55 kcal) was significantly lower than that in CON (1529 ± 55 kcal), and there was a relatively large degree of individual variability for exercise-induced changes in energy intake (−40.2% to 12.8%). However, exercise-induced changes in energy intake were not associated with plasma acylated ghrelin or PYY3-36 responses. The results demonstrated that a 20 km run significantly decreased plasma acylated ghrelin concentrations and absolute energy intake among well-trained long distance runners. PMID:27792164

Intermittent claudication-like syndrome secondary to atherosclerosis in a yellow-naped Amazon parrot (Amazona ochrocephala auropalliata).

PubMed

Beaufrère, Hugues; Holder, Kali A; Bauer, Rudy; Schnellbacher, Rodney; Pariaut, Romain; Tully, Thomas N; Wakamatsu, Nobuko

2011-12-01

A 25-year-old yellow-naped Amazon parrot (Amazona ochrocephala auropalliata) was presented for nasal discharge and sneezing. Physical examination revealed poor feather quality, a mild serous nasal discharge, and a mass on the dorsal surface of the oral cavity. Cytologic examination of a mass aspirate as well as results of a choanal culture revealed squamous metaplasia of the salivary glands and bacterial rhinitis, respectively. Following resolution of the presenting conditions, the patient was presented for hind limb weakness and ataxia. The clinical signs were transient and generally resolved with rest but could be reproduced after stressful episodes, such as restraint for procedures or treatment. Test results from a complete blood count, biochemistry profile, whole-body radiographs, needle electromyography of the leg muscles, and an edrophonium challenge test were within reference limits. Based on the clinical signs and results of the diagnostic workup, the presumptive diagnosis was intermittent claudication, a condition caused by peripheral vascular disease and defined as intermittent weakness and pain in the legs induced by exercise and relieved by rest. Shortly after initiation of treatment with isoxsuprine, the bird died. Postmortem examination and histopathology revealed severe atherosclerotic lesions throughout the vascular system with stenotic lesions present in the abdominal aorta and femoral arteries. Electron microscopic examination of the great arteries was also performed and helped to further characterize the nature of the lesions. This case is the first report, to our knowledge, of an intermittent claudication-like syndrome associated with peripheral atherosclerosis in a psittacine bird. In addition, the distribution and some of the macroscopic and histopathologic features of the lesions differ from previous descriptions of atherosclerosis in psittacine birds.

Superion Interspinous Spacer Treatment of Moderate Spinal Stenosis: 4-Year Results.

PubMed

Nunley, Pierce D; Patel, Vikas V; Orndorff, Douglas G; Lavelle, William F; Block, Jon E; Geisler, Fred H

2017-08-01

To determine 4-year clinical outcomes in patients with moderate lumbar spinal stenosis treated with minimally invasive stand-alone interspinous process decompression using the Superion device. The 4-year Superion data were extracted from a randomized, controlled Food and Drug Administration investigational device exemption trial. Patients with intermittent neurogenic claudication relieved with back flexion who failed at least 6 months of nonsurgical management were enrolled. Outcomes included Zurich Claudication Questionnaire (ZCQ) symptom severity (ss), physical function (pf) and patient satisfaction (ps) subdomains, leg and back pain visual analog scale (VAS), and Oswestry Disability Index (ODI). At 4-year follow-up, 89 of the 122 patients (73%) provided complete clinical outcome evaluations. At 4 years after index procedure, 75 of 89 patients with Superion (84.3%) demonstrated clinical success on at least 2 of 3 ZCQ domains. Individual component responder rates were 83% (74/89), 79% (70/89), and 87% (77/89) for ZCQss, ZCQpf, and ZCQps; 78% (67/86) and 66% (57/86) for leg and back pain VAS; and 62% (55/89) for ODI. Patients with Superion also demonstrated percentage improvements over baseline of 41%, 40%, 73%, 69%, and 61% for ZCQss, ZCQpf, leg pain VAS, back pain VAS, and ODI. Within-group effect sizes all were classified as very large (>1.0): 1.49, 1.65, 1.42, 1.12, and 1.46 for ZCQss, ZCQpf, leg pain VAS, back pain VAS, and ODI. Minimally invasive implantation of the Superion device provides long-term, durable relief of symptoms of intermittent neurogenic claudication for patients with moderate lumbar spinal stenosis. Copyright © 2017 Elsevier Inc. All rights reserved.

Recent trends in morbidity and in-hospital outcomes of in-patients with peripheral arterial disease: a nationwide population-based analysis.

PubMed

Malyar, Nasser; Fürstenberg, Torsten; Wellmann, Jürgen; Meyborg, Matthias; Lüders, Florian; Gebauer, Katrin; Bunzemeier, Holger; Roeder, Norbert; Reinecke, Holger

2013-09-01

The prevalence of peripheral arterial disease (PAD) and especially of critical limb ischaemia (CLI) is announced to rise dramatically worldwide, with a considerable impact on the health care and socio-economic systems. We aimed to characterize the recent trends in morbidity and in-hospital outcome of PAD among all hospitalized patients in the entire German population between 2005 and 2009. Nationwide data of all hospitalizations in Germany in 2005, 2007, and 2009 were analysed regarding the prevalence of PAD, comorbidities, endovascular (EVR) and surgical revascularizations (SR), major and minor amputations, in-hospital mortality, and associated costs. From 2005 to 2009, total PAD cases increased by 20.7% (from 400 928 to 483 961), with an increase of CLI subset from 40.6 to 43.5%. Total EVR increased by 46%, while thromb-embolectomy, endarterectomy, and patch plastic increased by 67, 42, and 21%, respectively. Peripheral bypasses decreased by 2%. Major amputation decreased from 4.6 to 3.5%, while minor amputation slightly increased from 4.98 to 5.11%. The crude overall in-hospital mortality remained unchanged in claudicants (2.2%), while it decreased from 9.8 to 8.4% in CLI patients. However, mortality rate according to the Poisson model (n/1000 hospital residence days) increased significantly in claudicants (P < 0.001). Total reimbursement costs for PAD in-patient care increased by 21% with an average per case costs in 2009 of €4506 in a claudicant and €6791 in a CLI patient. This population-based analysis documents the significant rise of PAD, particularly of the CLI subset, and highlights the malign prognosis associated with PAD as indicated by high amputation and in-hospital mortality rates.

Limb Stress-Rest Perfusion Imaging With Contrast Ultrasound For The Assessment Of Peripheral Arterial Disease Severity

PubMed Central

Lindner, Jonathan R.; Womack, Lisa; Barrett, Eugene J.; Feltman, Judy; Price, Wendy; Harthun, Nancy L.; Kaul, Sanjiv; Patrie, James T.

2009-01-01

Objectives We hypothesized that lower extremity stress-rest perfusion imaging with contrast-enhanced ultrasound (CEU) could evaluate the severity of peripheral arterial disease (PAD). Background Perfusion imaging may provide valuable quantitative information on PAD, particularly in patients with diabetes in whom microvascular functional abnormalities are common. Methods Twenty-six control subjects and 39 patients with symptomatic PAD, 19 with type-2 diabetes mellitus, were studied. Claudication threshold was determined by a modified treadmill exercise test. Bilateral pulse-volume recordings, ankle-brachial index (ABI), and post-exercise ABI were performed. CEU perfusion imaging of the gastrocnemius and soleus was performed at rest and after 2 min of plantar-flexion exercise. Results During exercise, claudication occurred earlier in PAD patients with diabetes than without. Muscle blood flow during plantar-flexion exercise was lower (p<0.05) in patients with PAD (10.4±6.7) and PAD with diabetes (7.9±5.9) compared to control subjects (20.0±9.5). After adjusting for diabetes, the only diagnostic tests that predicted severity of disease defined by claudication threshold were CEU exercise blood flow (odds ratios: 0.67 [95% CI (0.51 to 0.88); p=0.003], and flow reserve (odds ratio: 0.64 [95% CI (0.46 to 0.89), p=0.008]). A multivariate model incorporating all non-invasive diagnostic tests indicated that the best models for predicting severity of disease were the combination of presence of diabetes and either exercise blood flow or flow reserve. Conclusions Limb microvascular perfusion imaging during exercise can be evaluated by CEU. Skeletal muscle blood flow during exercise and flow reserve are impaired in patients with PAD and correlate with the severity of symptoms. PMID:19356447

Influence of Distance to Hospital and Insurance Status on the Rates of Contralateral Prophylactic Mastectomy, a National Cancer Data Base study.

PubMed

Ward, Erin P; Unkart, Jonathan T; Bryant, Alex; Murphy, James; Blair, Sarah L

2017-10-01

We evaluated the impact of travel distance and insurance status on contralateral prophylactic mastectomy (CPM) rates in breast cancer. We queried the National Cancer Data Base (NCDB) for women >18 years of age with a nonmetastatic primary breast cancer of ductal, lobular, or mixed histology. Patient- and facility-specific CPM rates were calculated based on insurance, race, and distance to treatment center. Standard univariable and multivariable regression analysis was performed. Overall, the CPM rate was 6.5% for the 864,105 patients identified. Most patients traveled <20 miles to a treatment center (79.5%) and had private insurance or Medicare (58.3 and 33.4%, respectively). In general, younger, White, non-Hispanic, and privately insured patients residing further from a treatment center was associated with increased rates of CPM. However, distance to the treatment center and insurance type had a greater absolute impact on rates of CPM for Black and Hispanic patients. Absolute CPM rate increases for patients >100 miles from a treatment center compared with those <20 miles from a treatment center were observed to be greater for Black and Hispanic patients (3.5 and 3.9%, respectively) compared with White and non-Hispanic patients (2.5 and 2.6%). Additionally, further patient travel distance was associated with higher treatment center-specific CPM rates. Increased travel distance is independently associated with increased rates of CPM for all patients and increased facility-specific rates of CPM. Black and Hispanic patients were found to be more vulnerable to the impact of travel distance and insurance status on rates of CPM.

Size Constancy in Bat Biosonar? Perceptual Interaction of Object Aperture and Distance

PubMed Central

Heinrich, Melina; Wiegrebe, Lutz

2013-01-01

Perception and encoding of object size is an important feature of sensory systems. In the visual system object size is encoded by the visual angle (visual aperture) on the retina, but the aperture depends on the distance of the object. As object distance is not unambiguously encoded in the visual system, higher computational mechanisms are needed. This phenomenon is termed “size constancy”. It is assumed to reflect an automatic re-scaling of visual aperture with perceived object distance. Recently, it was found that in echolocating bats, the ‘sonar aperture’, i.e., the range of angles from which sound is reflected from an object back to the bat, is unambiguously perceived and neurally encoded. Moreover, it is well known that object distance is accurately perceived and explicitly encoded in bat sonar. Here, we addressed size constancy in bat biosonar, recruiting virtual-object techniques. Bats of the species Phyllostomus discolor learned to discriminate two simple virtual objects that only differed in sonar aperture. Upon successful discrimination, test trials were randomly interspersed using virtual objects that differed in both aperture and distance. It was tested whether the bats spontaneously assigned absolute width information to these objects by combining distance and aperture. The results showed that while the isolated perceptual cues encoding object width, aperture, and distance were all perceptually well resolved by the bats, the animals did not assign absolute width information to the test objects. This lack of sonar size constancy may result from the bats relying on different modalities to extract size information at different distances. Alternatively, it is conceivable that familiarity with a behaviorally relevant, conspicuous object is required for sonar size constancy, as it has been argued for visual size constancy. Based on the current data, it appears that size constancy is not necessarily an essential feature of sonar perception in bats. PMID:23630598

Size constancy in bat biosonar? Perceptual interaction of object aperture and distance.

PubMed

Heinrich, Melina; Wiegrebe, Lutz

2013-01-01

Perception and encoding of object size is an important feature of sensory systems. In the visual system object size is encoded by the visual angle (visual aperture) on the retina, but the aperture depends on the distance of the object. As object distance is not unambiguously encoded in the visual system, higher computational mechanisms are needed. This phenomenon is termed "size constancy". It is assumed to reflect an automatic re-scaling of visual aperture with perceived object distance. Recently, it was found that in echolocating bats, the 'sonar aperture', i.e., the range of angles from which sound is reflected from an object back to the bat, is unambiguously perceived and neurally encoded. Moreover, it is well known that object distance is accurately perceived and explicitly encoded in bat sonar. Here, we addressed size constancy in bat biosonar, recruiting virtual-object techniques. Bats of the species Phyllostomus discolor learned to discriminate two simple virtual objects that only differed in sonar aperture. Upon successful discrimination, test trials were randomly interspersed using virtual objects that differed in both aperture and distance. It was tested whether the bats spontaneously assigned absolute width information to these objects by combining distance and aperture. The results showed that while the isolated perceptual cues encoding object width, aperture, and distance were all perceptually well resolved by the bats, the animals did not assign absolute width information to the test objects. This lack of sonar size constancy may result from the bats relying on different modalities to extract size information at different distances. Alternatively, it is conceivable that familiarity with a behaviorally relevant, conspicuous object is required for sonar size constancy, as it has been argued for visual size constancy. Based on the current data, it appears that size constancy is not necessarily an essential feature of sonar perception in bats.

Effect of diabetes on the cutaneous microcirculation of the feet in patients with intermittent claudication.

PubMed

Klonizakis, M; Manning, G; Lingam, K; Donnelly, R; Yeung, J M C

2015-01-01

To evaluate endothelial-dependent and - independent cutaneous vasodilator responses in the feet of patients with peripheral arterial disease (PAD) with or without Type 2 diabetes. Cutaneous microvascular responses in the dorsum of both lower limbs were measured in the supine position using Laser Doppler Fluximetry combined with iontophoretic administration of endothelial-dependent (acetylcholine, Ach) and -independent (sodium nitroprusside, SNP) vasodilators in diabetic (n = 19) and non diabetic (n = 17) patients with PAD (presenting as unilateral calf intermittent claudication (IC). In patients with diabetes and IC, endothelial-dependent vasodilation was significantly impaired in the symptomatic limb [74 (57,105) vs 68 (24,81) PU, Z =-2.79, p = 0.005] compared to the asymptomatic limb. Patients without diabetes showed no impairment of vasodilation. Resting ankle-brachial pressure index did not identify the presence of abnormalities in microvascular function. The combination of diabetes and PAD is associated with a reduction in endothelial-dependent cutaneous vasodilation in the feet without an associated reduction in endothelial independent vasodilation.

Lateral retroperitoneal transpsoas interbody fusion in a patient with achondroplastic dwarfism.

PubMed

Staub, Blake N; Holman, Paul J

2015-02-01

The authors present the first reported use of the lateral retroperitoneal transpsoas approach for interbody arthrodesis in a patient with achondroplastic dwarfism. The inherent anatomical abnormalities of the spine present in achondroplastic dwarfism predispose these patients to an increased incidence of spinal deformity as well as neurogenic claudication and potential radicular symptoms. The risks associated with prolonged general anesthesia and intolerance of significant blood loss in these patients makes them ideal candidates for minimally invasive spinal surgery. The patient in this case was a 51-year-old man with achondroplastic dwarfism who had a history of progressive claudication and radicular pain despite previous extensive lumbar laminectomies. The lateral retroperitoneal transpsoas approach was used for placement of interbody cages at L1/2, L2/3, L3/4, and L4/5, followed by posterior decompression and pedicle screw instrumentation. The patient tolerated the procedure well with no complications. Postoperatively his claudicatory and radicular symptoms resolved and a CT scan revealed solid arthrodesis with no periimplant lucencies.

A VLBI resolution of the Pleiades distance controversy.

PubMed

Melis, Carl; Reid, Mark J; Mioduszewski, Amy J; Stauffer, John R; Bower, Geoffrey C

2014-08-29

Because of its proximity and its youth, the Pleiades open cluster of stars has been extensively studied and serves as a cornerstone for our understanding of the physical properties of young stars. This role is called into question by the "Pleiades distance controversy," wherein the cluster distance of 120.2 ± 1.5 parsecs (pc) as measured by the optical space astrometry mission Hipparcos is significantly different from the distance of 133.5 ± 1.2 pc derived with other techniques. We present an absolute trigonometric parallax distance measurement to the Pleiades cluster that uses very long baseline radio interferometry (VLBI). This distance of 136.2 ± 1.2 pc is the most accurate and precise yet presented for the cluster and is incompatible with the Hipparcos distance determination. Our results cement existing astrophysical models for Pleiades-age stars. Copyright © 2014, American Association for the Advancement of Science.

Distance measurement using frequency scanning interferometry with mode-hoped laser

NASA Astrophysics Data System (ADS)

Medhat, M.; Sobee, M.; Hussein, H. M.; Terra, O.

2016-06-01

In this paper, frequency scanning interferometry is implemented to measure distances up to 5 m absolutely. The setup consists of a Michelson interferometer, an external cavity tunable diode laser, and an ultra-low expansion (ULE) Fabry-Pérot (FP) cavity to measure the frequency scanning range. The distance is measured by acquiring simultaneously the interference fringes from, the Michelson and the FP interferometers, while scanning the laser frequency. An online fringe processing technique is developed to calculate the distance from the fringe ratio while removing the parts result from the laser mode-hops without significantly affecting the measurement accuracy. This fringe processing method enables accurate distance measurements up to 5 m with measurements repeatability ±3.9×10-6 L. An accurate translation stage is used to find the FP cavity free-spectral-range and therefore allow accurate measurement. Finally, the setup is applied for the short distance calibration of a laser distance meter (LDM).

Commercial golf glove effects on golf performance and forearm muscle activity.

PubMed

Sorbie, Graeme G; Darroch, Paul; Grace, Fergal M; Gu, Yaodong; Baker, Julien S; Ugbolue, Ukadike C

2017-01-01

The study aimed to determine whether or not commercial golf gloves influence performance variables and forearm muscle activity during golf play. Fifteen golfers participated in the laboratory based study, each performing 8 golf swings with a Driver and 7-iron whilst wearing a glove and 8 without wearing the glove. Club head speed, ball speed and absolute carry distance performance variables were calculated. Surface electromyography was recorded from the flexor digitorum superficialis and extensor carpi radialis brevis on both forearm muscles. Club head speed, ball speed and absolute carry distance was significantly higher when using the Driver with the glove in comparison to the Driver without the glove (p < 0.05). No significant differences were evident when using the 7-iron and no significant differences were displayed in muscle activity in either of the conditions. Findings from this study suggest that driving performance is improved when wearing a glove.

Possible influences on bullet trajectory deflection in ballistic gelatine.

PubMed

Riva, Fabiano; Kerkhoff, Wim; Bolck, Annabel; Mattijssen, Erwin J A T

2017-02-01

The influence of the distance to the top and bottom of a gelatine block and to bullet tracks from previously fired shots on a bullet's trajectory, when passing through ballistic gelatine, was studied. No significant difference in deflection was found when trajectories of 9mm Luger bullets, fired at a 3.5cm distance to the top and bottom of a gelatine block and to bullet tracks from previously fired shots, were compared to trajectories of bullets fired 7cm or more away from any of the aforementioned aspects. A surprisingly consistent 6.5° absolute deflection angle was found when these bullets passed through 22.5 to 23.5cm of ballistic gelatine. The projection angle, determined by the direction of the deflection, appeared to be random. The consistent absolute angle, in combination with the random projection angle, resulted in a cone-like deflection pattern. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Evaluation of Cell Therapy on Exercise Performance and Limb Perfusion in Peripheral Artery Disease: The CCTRN Patients with Intermittent Claudication Injected with ALDH Bright Cells (PACE) Trial

PubMed Central

Perin, Emerson C.; Murphy, Michael P.; March, Keith L.; Bolli, Roberto; Loughran, John; Yang, Phillip C.; Leeper, Nicholas J.; Dalman, Ronald L.; Alexander, Jason; Henry, Timothy D.; Traverse, Jay H.; Pepine, Carl J.; Anderson, R. David; Berceli, Scott; Willerson, James T.; Muthupillai, Raja; Gahremanpour, Amir; Raveendran, Ganesh; Velasquez, Omaida; Hare, Joshua M.; Schulman, Ivonne Hernandez; Kasi, Vijaykumar S.; Hiatt, William R.; Ambale-Venkatesh, Bharath; Lima, João A.; Taylor, Doris A.; Resende, Micheline; Gee, Adrian P.; Durett, April G.; Bloom, Jeanette; Richman, Sara; G’Sell, Patricia; Williams, Shari; Khan, Fouzia; Ross, Elsie Gyang; Santoso, Michelle R.; Goldman, JoAnne; Leach, Dana; Handberg, Eileen; Cheong, Benjamin; Piece, Nichole; DiFede, Darcy; Bruhn-Ding, Barb; Caldwell, Emily; Bettencourt, Judy; Lai, Dejian; Piller, Linda; Simpson, Lara; Cohen, Michelle; Sayre, Shelly L.; Vojvodic, Rachel W.; Moyé, Lem; Ebert, Ray F.; Simari, Robert D.; Hirsch, Alan T.

2017-01-01

Background Atherosclerotic peripheral artery disease (PAD) affects 8–12% of Americans over 65 and is associated with a major decline in functional status, increased myocardial infarction and stroke rates, and increased risk of ischemic amputation. Current treatment strategies for claudication have limitations. PACE is an NHLBI-sponsored, randomized, double-blind, placebo-controlled phase 2, exploratory clinical trial designed to assess safety and efficacy of autologous bone marrow–derived aldehyde dehydrogenase bright (ALDHbr) cells in PAD patients and to explore associated claudication physiologic mechanisms. Methods All participants, randomized 1:1 to receive ALDHbr cells or placebo, underwent bone marrow aspiration and isolation of ALDHbr cells, followed by ten injections into the thigh and calf of the index leg. The co-primary endpoints were: change from baseline to six months in peak walking time (PWT), collateral count, peak hyperemic popliteal flow, and capillary perfusion measured by magnetic resonance imaging (MRI); as well as safety. Results A total of 82 patients with claudication and infra-inguinal PAD were randomized at nine sites, of which 78 had analyzable data (57 male, 21 female; mean age 66±9 years). The mean differences in the change over six months between study groups for PWT (mean ± standard error of the mean [SEM]) (0.9±0.8 minutes; 95% CI −0.6 to 2.5; p=0.238), collateral count (0.9±0.6 arteries; 95% CI −0.2 to 2.1; p=0.116), peak hyperemic popliteal flow (0.0±0.4 mL/sec; 95% CI −0.8 to 0.8; p=0.978), and capillary perfusion (−0.2±0.6%; 95% CI −1.3 to 0.9; p=0.752) were not significant. Additionally, there were no significant differences for the secondary endpoints, including quality of life measures. There were no adverse safety outcomes. Correlative relationships between MRI measures and PWT were not significant. A post-hoc exploratory analysis suggested that ALDHbr cell administration might be associated with an increase in the number of collateral arteries (1.5±0.7; 95% CI 0.1 to 2.9; p=0.047) in participants with completely occluded femoral arteries. Conclusions ALDHbr cell administration did not improve PWT or MR outcomes, and the changes in PWT were not associated with the anatomic or physiologic MRI endpoints. Future PAD cell therapy investigational trial design may be informed by new anatomic and perfusion insights. PMID:28209728

Absolute/convective secondary instabilities and the role of confinement in free shear layers

NASA Astrophysics Data System (ADS)

Arratia, Cristóbal; Mowlavi, Saviz; Gallaire, François

2018-05-01

We study the linear spatiotemporal stability of an infinite row of equal point vortices under symmetric confinement between parallel walls. These rows of vortices serve to model the secondary instability leading to the merging of consecutive (Kelvin-Helmholtz) vortices in free shear layers, allowing us to study how confinement limits the growth of shear layers through vortex pairings. Using a geometric construction akin to a Legendre transform on the dispersion relation, we compute the growth rate of the instability in different reference frames as a function of the frame velocity with respect to the vortices. This approach is verified and complemented with numerical computations of the linear impulse response, fully characterizing the absolute/convective nature of the instability. Similar to results by Healey on the primary instability of parallel tanh profiles [J. Fluid Mech. 623, 241 (2009), 10.1017/S0022112008005284], we observe a range of confinement in which absolute instability is promoted. For a parallel shear layer with prescribed confinement and mixing length, the threshold for absolute/convective instability of the secondary pairing instability depends on the separation distance between consecutive vortices, which is physically determined by the wavelength selected by the previous (primary or pairing) instability. In the presence of counterflow and moderate to weak confinement, small (large) wavelength of the vortex row leads to absolute (convective) instability. While absolute secondary instabilities in spatially developing flows have been previously related to an abrupt transition to a complex behavior, this secondary pairing instability regenerates the flow with an increased wavelength, eventually leading to a convectively unstable row of vortices. We argue that since the primary instability remains active for large wavelengths, a spatially developing shear layer can directly saturate on the wavelength of such a convectively unstable row, by-passing the smaller wavelengths of absolute secondary instability. This provides a wavelength selection mechanism, according to which the distance between consecutive vortices should be sufficiently large in comparison with the channel width in order for the row of vortices to persist. We argue that the proposed wavelength selection criteria can serve as a guideline for experimentally obtaining plane shear layers with counterflow, which has remained an experimental challenge.

Mode-resolved frequency comb interferometry for high-accuracy long distance measurement

PubMed Central

van den Berg, Steven. A.; van Eldik, Sjoerd; Bhattacharya, Nandini

2015-01-01

Optical frequency combs have developed into powerful tools for distance metrology. In this paper we demonstrate absolute long distance measurement using a single femtosecond frequency comb laser as a multi-wavelength source. By applying a high-resolution spectrometer based on a virtually imaged phased array, the frequency comb modes are resolved spectrally to the level of an individual mode. Having the frequency comb stabilized against an atomic clock, thousands of accurately known wavelengths are available for interferometry. From the spectrally resolved output of a Michelson interferometer a distance is derived. The presented measurement method combines spectral interferometry, white light interferometry and multi-wavelength interferometry in a single scheme. Comparison with a fringe counting laser interferometer shows an agreement within <10−8 for a distance of 50 m. PMID:26419282

Shannon: Theory and cryptography

NASA Astrophysics Data System (ADS)

Roefs, H. F. A.

1982-11-01

The ideas of Shannon as a theoretical basis for cryptography are discussed. The notion of mutual information is introduced to provide a deeper understanding of the functioning of cryptographic systems. Shannon's absolute secure cryptosystem and his notion of unicity distance are explained.

Patient selection and perioperative outcomes of bypass and endovascular intervention as first revascularization strategy for infrainguinal arterial disease.

PubMed

Bodewes, Thomas C F; Darling, Jeremy D; Deery, Sarah E; O'Donnell, Thomas F X; Pothof, Alexander B; Shean, Katie E; Moll, Frans L; Schermerhorn, Marc L

2018-01-01

The optimal initial revascularization strategy remains uncertain for patients with peripheral arterial disease. The purpose of this study was to evaluate current nationwide selection and perioperative outcomes of patients undergoing bypass or endovascular intervention for infrainguinal disease in those with no prior ipsilateral revascularization. Patients undergoing nonemergent first-time infrainguinal revascularization were identified in the Targeted Vascular module of the National Surgical Quality Improvement Program (NSQIP) for 2011 to 2014 and stratified by symptom status (chronic limb-threatening ischemia [CLTI] or claudication). Patients treated with endovascular intervention were compared with those who underwent bypass. Multivariable logistic regression was used to evaluate current selection of patients and to establish independent associations between first-time procedures and postoperative outcomes. Of 5998 first-time infrainguinal revascularizations performed, 3193 were bypass procedures (63% for CLTI) and 2805 were endovascular interventions (64% for CLTI). Current patient characteristics associated with an endovascular-first approach as opposed to bypass-first in CLTI patients were age ≥80 years, tissue loss, nonsmoking, functional dependence, diabetes, dialysis, and tibial lesions, whereas age ≥80 years, nonwhite race, nonsmoking, diabetes, and tibial lesions were associated with an endovascular approach for claudication. In comparing first-time endovascular intervention with bypass, there was no difference in 30-day mortality in CLTI patients (univariate: 2.1% vs 2.2%; adjusted: odds ratio [OR], 0.7; 95% confidence interval [CI], 0.4-1.1) or claudication patients (0.3% vs 0.6%). Among CLTI patients, endovascular-first intervention was associated with lower rates of major adverse cardiovascular event (3.6% vs 4.7%; OR, 0.6; 95% CI, 0.4-0.9), surgical site infection (0.9% vs 7.7%; OR, 0.1; 95% CI, 0.1-0.2), bleeding (8.5% vs 17%; OR, 0.4; 95% CI, 0.3-0.5), unplanned reoperation (13% vs 17%; OR, 0.7; 95% CI, 0.5-0.8), and unplanned readmission (17% vs 18%; OR, 0.8; 95% CI, 0.7-0.9). Patients with claudication undergoing endovascular-first intervention also had lower rates of major adverse cardiovascular event (0.8% vs 1.6%; OR, 0.4; 95% CI, 0.2-0.95), surgical site infection (0.7% vs 6.6%; OR, 0.1; 95% CI, 0.04-0.2), bleeding (2.3% vs 6.0%; OR, 0.3; 95% CI, 0.2-0.5), unplanned reoperation (4.3% vs 6.6%; OR, 0.6; 95% CI, 0.4-0.9), and unplanned readmission (5.9% vs 9.0%; OR, 0.6; 95% CI, 0.4-0.8). Conversely, endovascular-first intervention was associated with a higher rate of secondary revascularizations within 30 days for CLTI (4.3% vs 3.1%; OR, 1.6; 95% CI, 1.04-2.3) but not for claudication (2.6% vs 1.9%; OR, 1.7; 95% CI, 0.9-3.4). An endovascular-first approach as a revascularization strategy for infrainguinal disease was associated with substantially lower early morbidity but not mortality, at the cost of higher rates of postoperative secondary revascularizations. As a national representation of first-time revascularizations, this study highlights the early endovascular perioperative benefit, although more robust long-term data are needed to adopt either one strategy or the other in select patients with peripheral arterial disease. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Accurate physical laws can permit new standard units: The two laws F→=ma→ and the proportionality of weight to mass

NASA Astrophysics Data System (ADS)

Saslow, Wayne M.

2014-04-01

Three common approaches to F→=ma→ are: (1) as an exactly true definition of force F→ in terms of measured inertial mass m and measured acceleration a→; (2) as an exactly true axiom relating measured values of a→, F→ and m; and (3) as an imperfect but accurately true physical law relating measured a→ to measured F→, with m an experimentally determined, matter-dependent constant, in the spirit of the resistance R in Ohm's law. In the third case, the natural units are those of a→ and F→, where a→ is normally specified using distance and time as standard units, and F→ from a spring scale as a standard unit; thus mass units are derived from force, distance, and time units such as newtons, meters, and seconds. The present work develops the third approach when one includes a second physical law (again, imperfect but accurate)—that balance-scale weight W is proportional to m—and the fact that balance-scale measurements of relative weight are more accurate than those of absolute force. When distance and time also are more accurately measurable than absolute force, this second physical law permits a shift to standards of mass, distance, and time units, such as kilograms, meters, and seconds, with the unit of force—the newton—a derived unit. However, were force and distance more accurately measurable than time (e.g., time measured with an hourglass), this second physical law would permit a shift to standards of force, mass, and distance units such as newtons, kilograms, and meters, with the unit of time—the second—a derived unit. Therefore, the choice of the most accurate standard units depends both on what is most accurately measurable and on the accuracy of physical law.

A Comparison of Cilostazol and Pentoxifylline for Treating Intermittent Claudication

NASA Technical Reports Server (NTRS)

Dawson, David L.; Cutler, Bruce S.; Hiatt, William R.; Hobson, Robert W., II; Martin, John D.; Bortey, Enoch B.; Forbes, William P.; Strandness, D. Eugene, Jr.; Homick, Jerry L. (Technical Monitor)

1999-01-01

A randomized, double-blind, placebo-controlled, parallel-group, phase III multicenter trial was performed to evaluate the relative efficacy and safety of cilostazol and pentoxifylline. The study included 54 outpatient vascular clinics, including sites at Air Force, Veterans Affairs, tertiary care, and university hospitals in the United States. Of 922 consenting patients, 698 met the inclusion criteria, were randomized, and received treatment with either cilostazol 100 mg P0 twice a day, pentoxifylline 400 mg PO 3 times a day, or placebo. Treatment was double-dummy to ensure study blindness. Efficacy was primarily established by maximal walking distance (MWD), measured with constant-speed, variable-grade treadmill testing, assessed at baseline and at 4, 8, 12, 16, 20, and 24 weeks. Mean MWD of cilostazol-treated patients (n=227) was significantly improved at every visit compared with patients who received pentoxifylline (n=232) or placebo (n=239). After 24 weeks of cilostazol, mean MWD increased 53.9% (107.3 m) from baseline, and the effect had not plateaued. This was better (P < 0.001) than the 30.4% (64.4 m) MWD improvement with pentoxifylline. MWD improvement with pentoxifylline was similar (P = 0.82) to that of placebo (64.7 m). Deaths and serious adverse event rates were similar in each group. Common side effects included headache (27.8% with cilostazol, 11.2% with pentoxifylline, 11.7% with placebo), palpitations (17.2% with cilostazol, 2.2% with pentoxifylllne, 1.3% with placebo), and abnormal stools. Cilostazol was significantly better than pentoxifylline or placebo for increasing walking distances; pentoxifylline was no better than placebo.

Detecting Topological Defect Dark Matter Using Coherent Laser Ranging System

PubMed Central

Yang, Wanpeng; Leng, Jianxiao; Zhang, Shuangyou; Zhao, Jianye

2016-01-01

In the last few decades, optical frequency combs with high intensity, broad optical bandwidth, and directly traceable discrete wavelengths have triggered rapid developments in distance metrology. However, optical frequency combs to date have been limited to determine the absolute distance to an object (such as satellite missions). We propose a scheme for the detection of topological defect dark matter using a coherent laser ranging system composed of dual-combs and an optical clock via nongravitational signatures. The dark matter field, which comprises a defect, may interact with standard model particles, including quarks and photons, resulting in the alteration of their masses. Thus, a topological defect may function as a dielectric material with a distinctive frequency-depend index of refraction, which would cause the time delay of a periodic extraterrestrial or terrestrial light. When a topological defect passes through the Earth, the optical path of long-distance vacuum path is altered, this change in optical path can be detected through the coherent laser ranging system. Compared to continuous wavelength(cw) laser interferometry methods, dual-comb interferometry in our scheme excludes systematic misjudgement by measuring the absolute optical path length. PMID:27389642

Results from a U.S. absolute gravity survey

NASA Astrophysics Data System (ADS)

Zumberge, M. A.; Faller, J. E.; Gschwind, J.

Using the recently completed JILA absolute gravity meter, we made a survey of twelve sites in the United States. Over a period of eight weeks, the instrument was driven a total distance of nearly 20,000 km to sites in California, New Mexico, Colorado, Wyoming, Maryland and Massachusetts. The time spent in carrying out a measurement at a single location was typically one day. We report the results of the measurements in this survey along with earlier measurements made with the instrument, discuss the measurement accuracy and compare our results with other measurements.

Absolute method of measuring magnetic susceptibility

USGS Publications Warehouse

Thorpe, A.; Senftle, F.E.

1959-01-01

An absolute method of standardization and measurement of the magnetic susceptibility of small samples is presented which can be applied to most techniques based on the Faraday method. The fact that the susceptibility is a function of the area under the curve of sample displacement versus distance of the magnet from the sample, offers a simple method of measuring the susceptibility without recourse to a standard sample. Typical results on a few substances are compared with reported values, and an error of less than 2% can be achieved. ?? 1959 The American Institute of Physics.

THE ARAUCARIA PROJECT: ON THE TIP OF THE RED GIANT BRANCH DISTANCE DETERMINATION TO THE MAGELLANIC CLOUDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Górski, Marek; Gieren, Wolfgang; Catelan, Márcio

2016-06-01

We present a precise optical and near-infrared determination of the tip of the red giant branch (TRGB) brightness in the Large and Small Magellanic Clouds (respectively, LMC and SMC). The commonly used calibrations of the absolute magnitude of the TRGB lead to an overestimation of the distance to the LMC and SMC in the K band, and an underestimation of the distance in the optical I band for both galaxies. Reported discrepancies are at the level of 0.2 mag, with respect to the very accurate distance determinations to both MCs based on late-type eclipsing binaries. The differential distances between themore » LMC and SMC obtained in the J and K bands, and for the bolometric brightness are consistent with each other, and with the results obtained from eclipsing binaries and other distance indicators.« less

Kinematic hand parameters in front crawl at different paces of swimming.

PubMed

Samson, Mathias; Monnet, Tony; Bernard, Anthony; Lacouture, Patrick; David, Laurent

2015-11-05

The aim of this study was to investigate the evolution of kinematic hand parameters (sweepback angle, angle of attack, velocity, acceleration and orientation of the hand relative to the absolute coordinate system) throughout an aquatic stroke and to study the possible modifications caused by a variation of the swimming pace. Seventeen competitive swimmers swam at long distance, middle distance and sprint paces. Parameters were calculated from the trajectory of seven markers on the hand measured with an optoelectronic system. Results showed that kinematic hand parameters evolve differently depending on the pace. Angle of attack, sweepback angle, acceleration and orientation of the hand do not vary significantly. The velocity of the hand increases when the pace increases, but only during the less propulsive phases (entry and stretch and downsweep to catch). The more the pace increases and the more the absolute durations of the entry and stretch and downsweep to catch phases decrease. Absolute durations of the insweep and upsweep phases remain constant. During these phases, the propulsive hand forces calculated do not vary significantly when the pace increases. The increase of swimming pace is then explained by the swimmer's capacity to maintain propulsive phases rather than increasing the force generation within each cycle. Copyright © 2015 Elsevier Ltd. All rights reserved.

Is power-space a continuum? Distance effect during power judgments.

PubMed

Jiang, Tianjiao; Zhu, Lei

2015-12-01

Despite the increasing evidence suggesting that power processing can activate vertical space schema, it still remains unclear whether this power-space is dichotomic or continuous. Here we tested the nature of the power-space by the distance effect, a continuous property of space cognition. In two experiments, participants were required to judge the power of one single word (Experiment 1) or compare the power of two words presented in pairs (Experiment 2). The power distance was indexed by the absolute difference of power ratings. Results demonstrated that reaction time decreased with the power distance, whereas accuracy increased with the power distance. The findings indicated that different levels of power were presented as different vertical heights, implying that there was a common mechanism underlying space and power cognition. Copyright © 2015 Elsevier Inc. All rights reserved.

A new estimate of the Hubble constant using the Virgo cluster distance

NASA Astrophysics Data System (ADS)

Visvanathan, N.

The Hubble constant, which defines the size and age of the universe, remains substantially uncertain. Attention is presently given to an improved distance to the Virgo Cluster obtained by means of the 1.05-micron luminosity-H I width relation of spirals. In order to improve the absolute calibration of the relation, accurate distances to the nearby SMC, LMC, N6822, SEX A and N300 galaxies have also been obtained, on the basis of the near-IR P-L relation of the Cepheids. A value for the global Hubble constant of 67 + or 4 km/sec per Mpc is obtained.

Integrated Cuing Requirements (ICR) Study: Demonstration Data Base and Users Guide.

DTIC Science & Technology

1983-07-01

viewed with a servo-mounted televison camera and used to provide a visual scene for an observer in an ATD. Modulation: Mathematically, the absolute...i(b). CROSS REFERENCE The impact of stationary scene RESULTS. . details was also tested in this See (c) study. See Figure 33.5-1. Ial TEST APPARATUS...size. (See the discussion of * the impact of perceived distance on perceived size in Section 31._.) Figure 33.4-1 Perceived Distance and Velocity of Self

Absolute measurement of cerebral optical coefficients, hemoglobin concentration and oxygen saturation in old and young adults with near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Hallacoglu, Bertan; Sassaroli, Angelo; Wysocki, Michael; Guerrero-Berroa, Elizabeth; Schnaider Beeri, Michal; Haroutunian, Vahram; Shaul, Merav; Rosenberg, Irwin H.; Troen, Aron M.; Fantini, Sergio

2012-08-01

We present near-infrared spectroscopy measurement of absolute cerebral hemoglobin concentration and saturation in a large sample of 36 healthy elderly (mean age, 85±6 years) and 19 young adults (mean age, 28±4 years). Non-invasive measurements were obtained on the forehead using a commercially available multi-distance frequency-domain system and analyzed using a diffusion theory model for a semi-infinite, homogeneous medium with semi-infinite boundary conditions. Our study included repeat measurements, taken five months apart, on 16 elderly volunteers that demonstrate intra-subject reproducibility of the absolute measurements with cross-correlation coefficients of 0.9 for absorption coefficient (μa), oxy-hemoglobin concentration ([HbO2]), and total hemoglobin concentration ([HbT]), 0.7 for deoxy-hemoglobin concentration ([Hb]), 0.8 for hemoglobin oxygen saturation (StO2), and 0.7 for reduced scattering coefficient (). We found significant differences between the two age groups. Compared to young subjects, elderly subjects had lower cerebral [HbO2], [Hb], [HbT], and StO2 by 10±4 μM, 4±3 μM, 14±5 μM, and 6%±5%, respectively. Our results demonstrate the reliability and robustness of multi-distance near-infrared spectroscopy measurements based on a homogeneous model in the human forehead on a large sample of human subjects. Absolute, non-invasive optical measurements on the brain, such as those presented here, can significantly advance the development of NIRS technology as a tool for monitoring resting/basal cerebral perfusion, hemodynamics, oxygenation, and metabolism.

Absolute measurement of cerebral optical coefficients, hemoglobin concentration and oxygen saturation in old and young adults with near-infrared spectroscopy.

PubMed

Hallacoglu, Bertan; Sassaroli, Angelo; Wysocki, Michael; Guerrero-Berroa, Elizabeth; Schnaider Beeri, Michal; Haroutunian, Vahram; Shaul, Merav; Rosenberg, Irwin H; Troen, Aron M; Fantini, Sergio

2012-08-01

We present near-infrared spectroscopy measurement of absolute cerebral hemoglobin concentration and saturation in a large sample of 36 healthy elderly (mean age, 85 ± 6 years) and 19 young adults (mean age, 28 ± 4 years). Non-invasive measurements were obtained on the forehead using a commercially available multi-distance frequency-domain system and analyzed using a diffusion theory model for a semi-infinite, homogeneous medium with semi-infinite boundary conditions. Our study included repeat measurements, taken five months apart, on 16 elderly volunteers that demonstrate intra-subject reproducibility of the absolute measurements with cross-correlation coefficients of 0.9 for absorption coefficient (μa), oxy-hemoglobin concentration ([HbO2]), and total hemoglobin concentration ([HbT]), 0.7 for deoxy-hemoglobin concentration ([Hb]), 0.8 for hemoglobin oxygen saturation (StO2), and 0.7 for reduced scattering coefficient (μ's). We found significant differences between the two age groups. Compared to young subjects, elderly subjects had lower cerebral [HbO2], [Hb], [HbT], and StO2 by 10 ± 4 μM, 4 ± 3 μM, 14 ± 5 μM, and 6%±5%, respectively. Our results demonstrate the reliability and robustness of multi-distance near-infrared spectroscopy measurements based on a homogeneous model in the human forehead on a large sample of human subjects. Absolute, non-invasive optical measurements on the brain, such as those presented here, can significantly advance the development of NIRS technology as a tool for monitoring resting/basal cerebral perfusion, hemodynamics, oxygenation, and metabolism.

Athermal laser treatment of the diabetic leg

NASA Astrophysics Data System (ADS)

Ignat, P.; Suteanu, S.; Brojbeanu, Gabriela; Vasiliu, Virgil V.

1995-03-01

This work shows the result obtained in the medical clinic of the `Dr. I. Cantacuzino Hospital' on a lot of 43 diabetic patients using the `LASSIS' devices composed of a He-Ne laser and 4 semiconductor lasers. The 43 patients showed various clinic pictures of a diabetic leg (diabetic arteriopathy and neuropathy) 16 of the lot showed an arteriopathy with claudication and a decrease of pulses oscillometrically measurements, 15 had ulceration and a beginning of gangrene and the other 12 showed a plantary boring ill. There has been achieved an amelioration of the oscillometric index of the claudication while walking the amelioration of local circulation, together with the limitation of the necrosis. For the boring ill, there has been achieved the acceleration of the granulating and epithelization process avoiding surgeries, suppuration and cutaneous plasties. The response to the laser treatment was compared to the response to the classic treatment (vasodilatation surgery unstrapping, antibiotherapy) on a proving lot. We appreciated that the cicatrization and local vasodilatation with athermal laser treatment should be a hope for the treatment of patients suffering of diabetic arteriopathy and neuropathy.

Development of quality indicators for physiotherapy for patients with PAOD in the Netherlands: a Delphi study.

PubMed

Gijsbers, H J H; Lauret, G J; van Hofwegen, A; van Dockum, T A; Teijink, J A W; Hendriks, H J M

2016-06-01

The aim of the study was to develop quality indicators (QIs) for physiotherapy management of patients with intermittent claudication (IC) in the Netherlands. As part of an international six-step method to develop QIs, an online survey Delphi-procedure was completed. After two Delphi-rounds a validation round was performed. Twenty-six experts were recruited to participate in this study. Twenty-four experts completed two Delphi-rounds. A third round was conducted inviting 1200 qualified and registered physiotherapists of the Dutch integrated care network 'Claudicationet' to validate a draft set of quality indicators. Out of 83 potential QIs in the Dutch physiotherapy guideline on 'Intermittent claudication', consensus among the experts selected nine indicators. All nine quality indicators were validated by 300 physiotherapists. A final set of nine indicators was derived from (1) a Dutch evidence-based physiotherapy guideline, (2) an expert Delphi procedure and (3) a validation by 300 physiotherapists. This set of indicators should be validated in clinical practice. Copyright © 2015 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Parental intermittent claudication as risk factor for claudication in adults.

PubMed

Prushik, Scott G; Farber, Alik; Gona, Philimon; Shrader, Peter; Pencina, Michael J; D'Agostino, Ralph B; Murabito, Joanne M

2012-03-01

Little is known about the familial aggregation of intermittent claudication (IC). Our objective was to examine whether parental IC increased the risk of IC in adult offspring, independent of the established cardiovascular risk factors. We evaluated the Offspring Cohort Participants of the Framingham Heart Study who were ≥30 years old, cardiovascular disease free, and had both parents enrolled in the Framingham Heart Study (n = 2,970 unique participants, 53% women). Pooled proportional hazards regression analysis was used to examine whether the 12-year risk of incident IC in offspring participants was associated with parental IC, adjusting for age, gender, diabetes, smoking, systolic blood pressure, total cholesterol, high-density lipoprotein cholesterol, and antihypertensive and lipid treatment. Of the 909 person-examinations in the parental IC history group and 5,397 person-examinations in the no-parental IC history group, there were 101 incident IC events (29 with parental IC history and 72 without a parental IC history) during follow-up. The age- and gender-adjusted 12-year cumulative incidence rate per 1,000 person-years was 5.08 (95% confidence interval [CI] 2.74 to 7.33) and 2.34 (95% CI 1.46 to 3.19) in participants with and without a parental IC history. A parental history of IC significantly increased the risk of incident IC in the offspring (multivariable adjusted hazard ratio 1.81, 95% CI 1.14 to 2.88). The hazard ratio was unchanged, with an adjustment for the occurrence of cardiovascular disease (hazard ratio 1.83, 95% CI 1.15 to 2.91). In conclusion, IC in parents increases the risk of IC in adult offspring, independent of the established risk factors. These data suggest a genetic component of peripheral artery disease and support future research into genetic causes. Copyright © 2012 Elsevier Inc. All rights reserved.

Exploring physical activity behaviour - needs for and interest in a technology-delivered, home-based exercise programme among patients with intermittent claudication.

PubMed

Cornelis, Nils; Buys, Roselien; Fourneau, Inge; Dewit, Tijl; Cornelissen, Véronique

2018-02-01

Supervised walking is a first line therapy in peripheral arterial disease (PAD) with complaints of intermittent claudication. However, uptake of supervised programmes is low. Home-based exercise seems an appealing alternative; especially since technological advances, such as tele-coaching and tele-monitoring, may facilitate the process and support patients when adopting a physically active lifestyle. To guide the development of such an intervention, it is important to identify barriers of physical activity and the needs and interests for technology-enabled exercise in this patient group. PAD patients were recruited at the vascular centre of UZ Leuven (Belgium). A questionnaire assessing PA (SF-International Physical Activity Questionnaire), barriers to PA, and interest in technology-supported exercise (Technology Usage Questionnaire) was completed. Descriptive and correlation analyses were performed. Ninety-nine patients (76 men; mean age 69 years) completed the survey. Physical activity levels were low in 48 %, moderate in 29 %, and high in 23 %. Intermittent claudication itself is the most important barrier for enhanced PA, with most patients reporting pain (93 %), need for rest (92 %), and obstacles worsening their pain (74 %) as barriers. A total of 93 % participants owned a mobile phone; 76 % had Internet access. Eighty-seven reported the need for an exercise programme, with 67 % showing interest in tele-coaching to support exercise. If technology was available, three-quarter stated they would be interested in home-based tele-coaching using the Internet (preferably e-mails, 86 %); 50 % via mobile phone, 87 % preferred text messages. Both were inversely related to age (rpb = 0.363 and rpb = 0.255, p < 0.05). Acquaintance with elastic bands or gaming platforms was moderate (55 and 49 %, respectively), but patients were interested in using them as alternatives (84 and 42 %). Interest in platforms was age-dependent (rs = -0.508, p < 0.01). PAD patients show significant interest in technology-delivered exercise, offering opportunities to develop a guided home-based exercise programme.

Association Between Albuminuria and Duration of Diabetes and Myocardial Dysfunction and Peripheral Arterial Disease Among Patients With Stable Coronary Artery Disease in the BARI 2D Study

PubMed Central

Escobedo, Jorge; Rana, Jamal S.; Lombardero, Manuel S.; Albert, Stewart G.; Davis, Andrew M.; Kennedy, Frank P.; Mooradian, Arshag D.; Robertson, David G.; Srinivas, V. S.; Gebhart, Suzanne S. P.

2010-01-01

OBJECTIVE: To evaluate the effect of prior duration of diabetes, glycated hemoglobin level at study entry, and microalbuminuria or macroalbuminuria on the extent and severity of coronary artery disease (CAD) and peripheral arterial disease. PATIENTS AND METHODS: We studied baseline characteristics of the 2368 participants of the BARI 2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) study, a randomized clinical trial that evaluates treatment efficacy for patients with type 2 diabetes and angiographically documented stable CAD. Patients were enrolled from January 1, 2001, through March 31, 2005. Peripheral arterial disease was ascertained by an ankle-brachial index (ABI) of 0.9 or less, and extent of CAD was measured by presence of multivessel disease, a left ventricular ejection fraction (LVEF) of less than 50%, and myocardial jeopardy index. RESULTS: Duration of diabetes of 20 or more years was associated with increased risk of ABI of 0.9 or less (odds ratio [OR], 1.54; 95% confidence interval [CI], 1.04-2.26), intermittent claudication (OR, 1.61; 95% CI, 1.10-2.35), and LVEF of less than 50% (OR, 2.03; 95% CI, 1.37-3.02). Microalbuminuria was associated with intermittent claudication (OR, 1.53; 95% CI, 1.16-2.02) and ABI of 0.9 or less (OR, 1.31; 95% CI, 0.98-1.75), whereas macroalbuminuria was associated with abnormal ABI, claudication, and LVEF of less than 50%. There was a significant association between diabetes duration and extent of CAD as manifested by number of coronary lesions, but no other significant associations were observed between duration of disease, glycated hemoglobin levels, or albumin-to-creatinine ratio and other manifestations of CAD. CONCLUSION: Duration of diabetes and microalbuminuria or macroalbuminuria are important predictors of severity of peripheral arterial disease and left ventricular dysfunction in a cohort of patients selected for the presence of CAD. PMID:20042560

Finding Useful Questions: On Bayesian Diagnosticity, Probability, Impact, and Information Gain

ERIC Educational Resources Information Center

Nelson, Jonathan D.

2005-01-01

Several norms for how people should assess a question's usefulness have been proposed, notably Bayesian diagnosticity, information gain (mutual information), Kullback-Liebler distance, probability gain (error minimization), and impact (absolute change). Several probabilistic models of previous experiments on categorization, covariation assessment,…

A tunable, double-wavelength heterodyne detection interferometer with frequency-locked diode-pumped Nd:YAG sources for absolute measurements

NASA Astrophysics Data System (ADS)

Gelmini, E.; Minoni, U.; Docchio, F.

1995-08-01

A double heterodyne interferometric instrument using a tunable synthetic wavelength for the absolute measurements of distance and position is presented. The optical synthetic wavelength is generated by a pair of PZT-tunable diode-pumped Nd:YAG lasers operating at 1.064 μm. Based on a closed-loop scheme, a suitable electronic circuit has been developed to implement the frequency locking of the two lasers. A digital frequency comparator provides an error signal, used to control the slave laser, by comparing the laser beat frequency to a reference oscillator. Demodulation of the superheterodyne signals is obtained by a rf detector followed by low-pass filtering. Distance measurements are obtained by a digital phase meter gauging the phase difference between the demodulated signals from a measuring interferometer and from a reference interferometer. The paper presents the optical and the electronic layouts of the instrument as well as experimental results from a laboratory prototype.

The Long-Wave Infrared Earth Image as a Pointing Reference for Deep-Space Optical Communications

NASA Astrophysics Data System (ADS)

Biswas, A.; Piazzolla, S.; Peterson, G.; Ortiz, G. G.; Hemmati, H.

2006-11-01

Optical communications from space require an absolute pointing reference. Whereas at near-Earth and even planetary distances out to Mars and Jupiter a laser beacon transmitted from Earth can serve as such a pointing reference, for farther distances extending to the outer reaches of the solar system, the means for meeting this requirement remains an open issue. We discuss in this article the prospects and consequences of utilizing the Earth image sensed in the long-wave infrared (LWIR) spectral band as a beacon to satisfy the absolute pointing requirements. We have used data from satellite-based thermal measurements of Earth to synthesize images at various ranges and have shown the centroiding accuracies that can be achieved with prospective LWIR image sensing arrays. The nonuniform emissivity of Earth causes a mispointing bias error term that exceeds a provisional pointing budget allocation when using simple centroiding algorithms. Other issues related to implementing thermal imaging of Earth from deep space for the purposes of providing a pointing reference are also reported.

Analytical gradients for subsystem density functional theory within the slater-function-based amsterdam density functional program.

PubMed

Schlüns, Danny; Franchini, Mirko; Götz, Andreas W; Neugebauer, Johannes; Jacob, Christoph R; Visscher, Lucas

2017-02-05

We present a new implementation of analytical gradients for subsystem density-functional theory (sDFT) and frozen-density embedding (FDE) into the Amsterdam Density Functional program (ADF). The underlying theory and necessary expressions for the implementation are derived and discussed in detail for various FDE and sDFT setups. The parallel implementation is numerically verified and geometry optimizations with different functional combinations (LDA/TF and PW91/PW91K) are conducted and compared to reference data. Our results confirm that sDFT-LDA/TF yields good equilibrium distances for the systems studied here (mean absolute deviation: 0.09 Å) compared to reference wave-function theory results. However, sDFT-PW91/PW91k quite consistently yields smaller equilibrium distances (mean absolute deviation: 0.23 Å). The flexibility of our new implementation is demonstrated for an HCN-trimer test system, for which several different setups are applied. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Echocardiographic left ventricular masses in distance runners and weight lifters

NASA Technical Reports Server (NTRS)

Longhurst, J. C.; Gonyea, W. J.; Mitchell, J. H.; Kelly, A. R.

1980-01-01

The relationships of different forms of exercise training to left ventricular mass and body mass are investigated by echocardiographic studies of weight lifters, long-distance runners, and comparatively sized untrained control subjects. Left ventricular mass determinations by the Penn convention reveal increased absolute left ventricular masses in long-distance runners and competitive weight lifters with respect to controls matched for age, body weight, and body surface area, and a significant correlation between ventricular mass and lean body mass. When normalized to lean body mass, the ventricular masses of distance runners are found to be significantly higher than those of the other groups, suggesting that dynamic training elevates left ventricular mass compared to static training and no training, while static training increases ventricular mass only to the extent that lean body mass is increased.

Post-traumatic orbital reconstruction: anatomical landmarks and the concept of the deep orbit.

PubMed

Evans, B T; Webb, A A C

2007-04-01

Dissection deep within the orbit is a cause for concern to surgeons because of the perceived risks of injuring critical structures such as the contents of the superior orbital fissure and the optic nerve. Although "safe distances" (those distances within which it is considered safe to dissect within the orbit) have been described, these are of limited value if the orbit is severely disrupted or is congenitally shallow. In addition, traumatic defects in the orbital floor, in particular, often extend beyond these distances. Reliable landmarks based on the relations between anatomical structures within the orbit, rather than absolute distances, are described that permit safe dissection within the orbit. We present the concept of the deep orbit and describe its relevance to repair of injuries.

Results from an absolute gravity survey in the United States

NASA Technical Reports Server (NTRS)

Zumberge, M. A.; Faller, J. E.; Gschwind, J.

1983-01-01

Using the recently completed JTLA absolute gravity meter, we made a survey of twelve sites in the United States. Over a period of eight weeks, the instrument was driven a total distance of nearly 20,000 km to sites in California, New Mexico, Colorado, Wyoming, Maryland and Massachusetts. The time spent in carrying out a measurement at a single location was typically one day. We report the results of the measurements in this survey along with earlier measurements made with the instrument, discuss the measurement accuracy and compare our results with other measurements. Previously announced in STAR as N83-20480

Results from an absolute gravity survey in the United States

NASA Astrophysics Data System (ADS)

Zumberge, M. A.; Faller, J. E.; Gschwind, J.

1983-09-01

Using the recently completed JTLA absolute gravity meter, we made a survey of twelve sites in the United States. Over a period of eight weeks, the instrument was driven a total distance of nearly 20,000 km to sites in California, New Mexico, Colorado, Wyoming, Maryland and Massachusetts. The time spent in carrying out a measurement at a single location was typically one day. We report the results of the measurements in this survey along with earlier measurements made with the instrument, discuss the measurement accuracy and compare our results with other measurements. Previously announced in STAR as N83-20480

Carotid-Femoral Pulse Wave Velocity: Impact of Different Arterial Path Length Measurements

PubMed Central

Sugawara, Jun; Hayashi, Koichiro; Yokoi, Takashi; Tanaka, Hirofumi

2009-01-01

Background Carotid-femoral pulse wave velocity (PWV) is the most established index of arterial stiffness. Yet there is no consensus on the methodology in regard to the arterial path length measurements conducted on the body surface. Currently, it is not known to what extent the differences in the arterial path length measurements affect absolute PWV values. Methods Two hundred fifty apparently healthy adults (127 men and 123 women, 19-79 years) were studied. Carotid-femoral PWV was calculated using (1) the straight distance between carotid and femoral sites (PWVcar–fem), (2) the straight distance between suprasternal notch and femoral site minus carotid arterial length (PWV(ssn–fem)-(ssn–car)), (3) the straight distance between carotid and femoral sites minus carotid arterial length (PWV(car–fem)-(ssn–car)), and (4) the combined distance from carotid site to the umbilicus and from the umbilicus to femoral site minus carotid arterial length (PWV(ssn–umb–fem)-(ssn–car)). Results All the calculated PWV were significantly correlated with each other (r=0.966-0.995). PWV accounting for carotid arterial length were 16-31% lower than PWVcar–fem. PWVcar–fem value of 12 m/sec corresponded to 8.3 m/sec for PWV(ssn–fem)-(ssn–car), 10.0 m/sec for PWV(car–fem)-(ssn–car), and 8.9 m/sec for PWV(ssn–umb–fem)-(ssn–car). Conclusion Different body surface measurements used to estimate arterial path length would produce substantial variations in absolute PWV values. PMID:20396400

Expectation affects verbal judgments but not reaches to visually perceived egocentric distances.

PubMed

Pagano, Christopher C; Isenhower, Robert W

2008-04-01

Two response measures for reporting visually perceived egocentric distances-verbal judgments and blind manual reaches-were compared using a within-trial methodology. The expected range of possible target distances was manipulated by instructing the subjects that the targets would be between .50 and 1.00 of their maximum arm reach in one session and between .25 and .90 in another session. The actual range of target distances was always .50-.90. Verbal responses varied as a function of the range of expected distances, whereas simultaneous reaches remained unaffected. These results suggest that verbal responses are subject to a cognitive influence that does not affect actions. It is suggested that action responses are indicative of absolute perception, whereas cognitive responses may reflect only relative perception. The results also indicate that the dependant variable utilized for the study of depth perception will influence the obtained results.

Technique for long and absolute distance measurement based on laser pulse repetition frequency sweeping

NASA Astrophysics Data System (ADS)

Castro Alves, D.; Abreu, Manuel; Cabral, A.; Jost, Michael; Rebordão, J. M.

2017-11-01

In this work we present a technique to perform long and absolute distance measurements based on mode-locked diode lasers. Using a Michelson interferometer, it is possible to produce an optical cross-correlation between laser pulses of the reference arm with the pulses from the measurement arm, adjusting externally their degree of overlap either changing the pulse repetition frequency (PRF) or the position of the reference arm mirror for two (or more) fixed frequencies. The correlation of the travelling pulses for precision distance measurements relies on ultra-short pulse durations, as the uncertainty associated to the method is dependent on the laser pulse width as well as on a highly stable PRF. Mode-locked Diode lasers are a very appealing technology for its inherent characteristics, associated to compactness, size and efficiency, constituting a positive trade-off with regard to other mode-locked laser sources. Nevertheless, main current drawback is the non-availability of frequency-stable laser diodes. The laser used is a monolithic mode-locked semiconductor quantum-dot (QD) laser. The laser PRF is locked to an external stabilized RF reference. In this work we will present some of the preliminary results and discuss the importance of the requirements related to laser PRF stability in the final metrology system accuracy.

The VMC Survey. XIX. Classical Cepheids in the Small Magellanic Cloud

NASA Astrophysics Data System (ADS)

Ripepi, V.; Marconi, M.; Moretti, M. I.; Clementini, G.; Cioni, M.-R. L.; de Grijs, R.; Emerson, J. P.; Groenewegen, M. A. T.; Ivanov, V. D.; Piatti, A. E.

2016-06-01

The “VISTA near-infrared YJK s survey of the Magellanic Clouds System” (VMC) is collecting deep K s-band time-series photometry of pulsating variable stars hosted by the two Magellanic Clouds and their connecting Bridge. In this paper, we present Y, J, K s light curves for a sample of 4172 Small Magellanic Cloud (SMC) Classical Cepheids (CCs). These data, complemented with literature V values, allowed us to construct a variety of period-luminosity (PL), period-luminosity-color (PLC), and period-Wesenheit (PW) relationships, which are valid for Fundamental (F), First Overtone (FO), and Second Overtone (SO) pulsators. The relations involving the V, J, K s bands are in agreement with their counterparts in the literature. As for the Y band, to our knowledge, we present the first CC PL, PW, and PLC relations ever derived using this filter. We also present the first near-infrared PL, PW, and PLC relations for SO pulsators to date. We used PW(V, K s) to estimate the relative SMC-LMC distance and, in turn, the absolute distance to the SMC. For the former quantity, we find a value of Δμ = 0.55 ± 0.04 mag, which is in rather good agreement with other evaluations based on CCs, but significantly larger than the results obtained from older population II distance indicators. This discrepancy might be due to the different geometric distributions of young and old tracers in both Clouds. As for the absolute distance to the SMC, our best estimates are μ SMC = 19.01 ± 0.05 mag and μ SMC = 19.04 ± 0.06 mag, based on two distance measurements to the LMC which rely on accurate CC and eclipsing Cepheid binary data, respectively.

Vertical gaze angle: absolute height-in-scene information for the programming of prehension.

PubMed

Gardner, P L; Mon-Williams, M

2001-02-01

One possible source of information regarding the distance of a fixated target is provided by the height of the object within the visual scene. It is accepted that this cue can provide ordinal information, but generally it has been assumed that the nervous system cannot extract "absolute" information from height-in-scene. In order to use height-in-scene, the nervous system would need to be sensitive to ocular position with respect to the head and to head orientation with respect to the shoulders (i.e. vertical gaze angle or VGA). We used a perturbation technique to establish whether the nervous system uses vertical gaze angle as a distance cue. Vertical gaze angle was perturbed using ophthalmic prisms with the base oriented either up or down. In experiment 1, participants were required to carry out an open-loop pointing task whilst wearing: (1) no prisms; (2) a base-up prism; or (3) a base-down prism. In experiment 2, the participants reached to grasp an object under closed-loop viewing conditions whilst wearing: (1) no prisms; (2) a base-up prism; or (3) a base-down prism. Experiment 1 and 2 provided clear evidence that the human nervous system uses vertical gaze angle as a distance cue. It was found that the weighting attached to VGA decreased with increasing target distance. The weighting attached to VGA was also affected by the discrepancy between the height of the target, as specified by all other distance cues, and the height indicated by the initial estimate of the position of the supporting surface. We conclude by considering the use of height-in-scene information in the perception of surface slant and highlight some of the complexities that must be involved in the computation of environmental layout.

Bilateral paracoccidioidomycotic iliopsoas abscess associated with ileo-colonic lesion.

PubMed

Duani, Helena; Nunes, Vinícius Rodrigues Taranto; Assumpção, Anísio Borges; Saraiva, Isadora Sofia Borges; Rosa, Rodrigo Macedo; Neiva, Augusto Motta; Pedroso, Enio Roberto Pietra

2012-10-01

This case report shows the clinical development of a patient with systemic paracoccidioidomycosis presenting with lymphatic-intestinalmanifestation. The patient initially had a substantial clinical improvement but had a recrudescence after six months of sulfamethoxazoletrimethoprim oral treatment, with the emergence of feverish syndrome, lumbar pain, and intermittent claudication, characterizing a bilateral iliopsoas muscle abscess, necessitating clinicosurgical therapeutics.

Optoelectronic device for the measurement of the absolute linear position in the micrometric displacement range

NASA Astrophysics Data System (ADS)

Morlanes, Tomas; de la Pena, Jose L.; Sanchez-Brea, Luis M.; Alonso, Jose; Crespo, Daniel; Saez-Landete, Jose B.; Bernabeu, Eusebio

2005-07-01

In this work, an optoelectronic device that provides the absolute position of a measurement element with respect to a pattern scale upon switch-on is presented. That means that there is not a need to perform any kind of transversal displacement after the startup of the system. The optoelectronic device is based on the process of light propagation passing through a slit. A light source with a definite size guarantees the relation of distances between the different elements that constitute our system and allows getting a particular optical intensity profile that can be measured by an electronic post-processing device providing the absolute location of the system with a resolution of 1 micron. The accuracy of this measuring device is restricted to the same limitations of any incremental position optical encoder.

Optimization methods of pulse-to-pulse alignment using femtosecond pulse laser based on temporal coherence function for practical distance measurement

NASA Astrophysics Data System (ADS)

Liu, Yang; Yang, Linghui; Guo, Yin; Lin, Jiarui; Cui, Pengfei; Zhu, Jigui

2018-02-01

An interferometer technique based on temporal coherence function of femtosecond pulses is demonstrated for practical distance measurement. Here, the pulse-to-pulse alignment is analyzed for large delay distance measurement. Firstly, a temporal coherence function model between two femtosecond pulses is developed in the time domain for the dispersive unbalanced Michelson interferometer. Then, according to this model, the fringes analysis and the envelope extraction process are discussed. Meanwhile, optimization methods of pulse-to-pulse alignment for practical long distance measurement are presented. The order of the curve fitting and the selection of points for envelope extraction are analyzed. Furthermore, an averaging method based on the symmetry of the coherence function is demonstrated. Finally, the performance of the proposed methods is evaluated in the absolute distance measurement of 20 μ m with path length difference of 9 m. The improvement of standard deviation in experimental results shows that these approaches have the potential for practical distance measurement.

Padé Approximant and Minimax Rational Approximation in Standard Cosmology

NASA Astrophysics Data System (ADS)

Zaninetti, Lorenzo

2016-02-01

The luminosity distance in the standard cosmology as given by $\\Lambda$CDM and consequently the distance modulus for supernovae can be defined by the Pad\\'e approximant. A comparison with a known analytical solution shows that the Pad\\'e approximant for the luminosity distance has an error of $4\\%$ at redshift $= 10$. A similar procedure for the Taylor expansion of the luminosity distance gives an error of $4\\%$ at redshift $=0.7 $; this means that for the luminosity distance, the Pad\\'e approximation is superior to the Taylor series. The availability of an analytical expression for the distance modulus allows applying the Levenberg--Marquardt method to derive the fundamental parameters from the available compilations for supernovae. A new luminosity function for galaxies derived from the truncated gamma probability density function models the observed luminosity function for galaxies when the observed range in absolute magnitude is modeled by the Pad\\'e approximant. A comparison of $\\Lambda$CDM with other cosmologies is done adopting a statistical point of view.

Noninvasive assessment of testicular torsion in rabbits using frequency-domain near-infrared spectroscopy: prospects for pediatric urology

NASA Astrophysics Data System (ADS)

Hallacoglu, Bertan; Matulewicz, Richard S.; Paltiel, Harriet J.; Padua, Horacio; Gargollo, Patricio; Cannon, Glenn; Alomari, Ahmad; Sassaroli, Angelo; Fantini, Sergio

2009-09-01

We present a quantitative near-IR spectroscopy study of the absolute values of oxygen saturation of hemoglobin before and after surgically induced testicular torsion in adult rabbits. Unilateral testicular torsions (0, 540, or 720 deg) on experimental testes and contralateral sham surgery on control testes are performed in four adult rabbits. A specially designed optical probe for measurements at multiple source-detector distances and a commercial frequency-domain tissue spectrometer are used to measure absolute values of testicular hemoglobin saturation. Our results show: (1) a consistent baseline absolute tissue hemoglobin saturation value of 78+/-5%, (2) a comparable tissue hemoglobin saturation of 77+/-6% after sham surgery, and (3) a significantly lower tissue hemoglobin saturation of 36+/-2% after 540- and 720-deg testicular torsion surgery. Our findings demonstrate the feasibility of performing frequency-domain, multidistance near-IR spectroscopy for absolute testicular oximetry in the assessment of testicular torsion. We conclude that near-IR spectroscopy has potential to serve as a clinical diagnostic and monitoring tool for the assessment of absolute testicular hemoglobin desaturation caused by torsion, with the possibility of serving as a complement to conventional color and spectral Doppler ultrasonography.

Globular Clusters: Absolute Proper Motions and Galactic Orbits

NASA Astrophysics Data System (ADS)

Chemel, A. A.; Glushkova, E. V.; Dambis, A. K.; Rastorguev, A. S.; Yalyalieva, L. N.; Klinichev, A. D.

2018-04-01

We cross-match objects from several different astronomical catalogs to determine the absolute proper motions of stars within the 30-arcmin radius fields of 115 Milky-Way globular clusters with the accuracy of 1-2 mas yr-1. The proper motions are based on positional data recovered from the USNO-B1, 2MASS, URAT1, ALLWISE, UCAC5, and Gaia DR1 surveys with up to ten positions spanning an epoch difference of up to about 65 years, and reduced to Gaia DR1 TGAS frame using UCAC5 as the reference catalog. Cluster members are photometrically identified by selecting horizontal- and red-giant branch stars on color-magnitude diagrams, and the mean absolute proper motions of the clusters with a typical formal error of about 0.4 mas yr-1 are computed by averaging the proper motions of selected members. The inferred absolute proper motions of clusters are combined with available radial-velocity data and heliocentric distance estimates to compute the cluster orbits in terms of the Galactic potential models based on Miyamoto and Nagai disk, Hernquist spheroid, and modified isothermal dark-matter halo (axisymmetric model without a bar) and the same model + rotating Ferre's bar (non-axisymmetric). Five distant clusters have higher-than-escape velocities, most likely due to large errors of computed transversal velocities, whereas the computed orbits of all other clusters remain bound to the Galaxy. Unlike previously published results, we find the bar to affect substantially the orbits of most of the clusters, even those at large Galactocentric distances, bringing appreciable chaotization, especially in the portions of the orbits close to the Galactic center, and stretching out the orbits of some of the thick-disk clusters.

Perception of Egocentric Distance during Gravitational Changes in Parabolic Flight.

PubMed

Clément, Gilles; Loureiro, Nuno; Sousa, Duarte; Zandvliet, Andre

2016-01-01

We explored the effect of gravity on the perceived representation of the absolute distance of objects to the observers within the range from 1.5-6 m. Experiments were performed on board the CNES Airbus Zero-G during parabolic flights eliciting repeated exposures to short periods of microgravity (0 g), hypergravity (1.8 g), and normal gravity (1 g). Two methods for obtaining estimates of perceived egocentric distance were used: verbal reports and visually directed motion toward a memorized visual target. For the latter method, because normal walking is not possible in 0 g, blindfolded subjects translated toward the visual target by pulling on a rope with their arms. The results showed that distance estimates using both verbal reports and blind pulling were significantly different between normal gravity, microgravity, and hypergravity. Compared to the 1 g measurements, the estimates of perceived distance using blind pulling were shorter for all distances in 1.8 g, whereas in 0 g they were longer for distances up to 4 m and shorter for distances beyond. These findings suggest that gravity plays a role in both the sensorimotor system and the perceptual/cognitive system for estimating egocentric distance.

Perception of Egocentric Distance during Gravitational Changes in Parabolic Flight

PubMed Central

Clément, Gilles; Loureiro, Nuno; Sousa, Duarte; Zandvliet, Andre

2016-01-01

We explored the effect of gravity on the perceived representation of the absolute distance of objects to the observers within the range from 1.5–6 m. Experiments were performed on board the CNES Airbus Zero-G during parabolic flights eliciting repeated exposures to short periods of microgravity (0 g), hypergravity (1.8 g), and normal gravity (1 g). Two methods for obtaining estimates of perceived egocentric distance were used: verbal reports and visually directed motion toward a memorized visual target. For the latter method, because normal walking is not possible in 0 g, blindfolded subjects translated toward the visual target by pulling on a rope with their arms. The results showed that distance estimates using both verbal reports and blind pulling were significantly different between normal gravity, microgravity, and hypergravity. Compared to the 1 g measurements, the estimates of perceived distance using blind pulling were shorter for all distances in 1.8 g, whereas in 0 g they were longer for distances up to 4 m and shorter for distances beyond. These findings suggest that gravity plays a role in both the sensorimotor system and the perceptual/cognitive system for estimating egocentric distance. PMID:27463106

Avoiding Degeneracy in Multidimensional Unfolding by Penalizing on the Coefficient of Variation

ERIC Educational Resources Information Center

Busing, Frank M. T. A.; Groenen, Patrick J. K.; Heiser, Willem J.

2005-01-01

Multidimensional unfolding methods suffer from the degeneracy problem in almost all circumstances. Most degeneracies are easily recognized: the solutions are perfect but trivial, characterized by approximately equal distances between points from different sets. A definition of an absolutely degenerate solution is proposed, which makes clear that…

Physiological Responses and Physical Performance during Football in the Heat

PubMed Central

Mohr, Magni; Nybo, Lars; Grantham, Justin; Racinais, Sebastien

2012-01-01

Purpose To examine the impact of hot ambient conditions on physical performance and physiological responses during football match-play. Methods Two experimental games were completed in temperate (∼21°C; CON) and hot ambient conditions (∼43°C; HOT). Physical performance was assessed by match analysis in 17 male elite players during the games and a repeated sprint test was conducted after the two game trials. Core and muscle temperature were measured and blood samples were obtained, before and after the games. Results Muscle and core temperatures were ∼1°C higher (P<0.05) in HOT (40.3±0.1 and 39.5±0.1°C, respectively) compared to CON (39.2±0.1 and 38.3±0.1°C). Average heart rate, plasma lactate concentration, body weight loss as well as post-game sprint performance were similar between the two conditions. Total game distance declined (P<0.05) by 7% and high intensity running (>14 km⋅h−1) by 26% in HOT compared to CON), but peak sprint speed was 4% higher (P<0.05) in HOT than in CON, while there were no differences in the quantity or length of sprints (>24 km⋅h−1) between CON and HOT. In HOT, success rates for passes and crosses were 8 and 9% higher (P<0.05), respectively, compared to CON. Delta increase in core temperature and absolute core temperature in HOT were correlated to total game distance in the heat (r = 0.85 and r = 0.53, respectively; P<0.05), whereas, total and high intensity distance deficit between CON and HOT were not correlated to absolute or delta changes in muscle or core temperature. Conclusion Total game distance and especially high intensity running were lower during a football game in the heat, but these changes were not directly related to the absolute or relative changes in core or muscle temperature. However, peak sprinting speed and execution of successful passes and crosses were improved in the HOT condition. PMID:22723963

Fourier Transform Fringe-Pattern Analysis of an Absolute Distance Michelson Interferometer for Space-Based Laser Metrology.

NASA Astrophysics Data System (ADS)

Talamonti, James Joseph

1995-01-01

Future NASA proposals include the placement of optical interferometer systems in space for a wide variety of astrophysical studies including a vastly improved deflection test of general relativity, a precise and direct calibration of the Cepheid distance scale, and the determination of stellar masses (Reasenberg et al., 1988). There are also plans for placing large array telescopes on the moon with the ultimate objective of being able to measure angular separations of less than 10 mu-arc seconds (Burns, 1990). These and other future projects will require interferometric measurement of the (baseline) distance between the optical elements comprising the systems. Eventually, space qualifiable interferometers capable of picometer (10^{-12}m) relative precision and nanometer (10^{ -9}m) absolute precision will be required. A numerical model was developed to emulate the capabilities of systems performing interferometric noncontact absolute distance measurements. The model incorporates known methods to minimize signal processing and digital sampling errors and evaluates the accuracy limitations imposed by spectral peak isolation using Hanning, Blackman, and Gaussian windows in the Fast Fourier Transform Technique. We applied this model to the specific case of measuring the relative lengths of a compound Michelson interferometer using a frequency scanned laser. By processing computer simulated data through our model, the ultimate precision is projected for ideal data, and data containing AM/FM noise. The precision is shown to be limited by non-linearities in the laser scan. A laboratory system was developed by implementing ultra-stable external cavity diode lasers into existing interferometric measuring techniques. The capabilities of the system were evaluated and increased by using the computer modeling results as guidelines for the data analysis. Experimental results measured 1-3 meter baselines with <20 micron precision. Comparison of the laboratory and modeling results showed that the laboratory precisions obtained were of the same order of magnitude as those predicted for computer generated results under similar conditions. We believe that our model can be implemented as a tool in the design for new metrology systems capable of meeting the precisions required by space-based interferometers.

Application of Intra-Oral Dental Scanners in the Digital Workflow of Implantology

PubMed Central

van der Meer, Wicher J.; Andriessen, Frank S.; Wismeijer, Daniel; Ren, Yijin

2012-01-01

Intra-oral scanners will play a central role in digital dentistry in the near future. In this study the accuracy of three intra-oral scanners was compared. Materials and methods: A master model made of stone was fitted with three high precision manufactured PEEK cylinders and scanned with three intra-oral scanners: the CEREC (Sirona), the iTero (Cadent) and the Lava COS (3M). In software the digital files were imported and the distance between the centres of the cylinders and the angulation between the cylinders was assessed. These values were compared to the measurements made on a high accuracy 3D scan of the master model. Results: The distance errors were the smallest and most consistent for the Lava COS. The distance errors for the Cerec were the largest and least consistent. All the angulation errors were small. Conclusions: The Lava COS in combination with a high accuracy scanning protocol resulted in the smallest and most consistent errors of all three scanners tested when considering mean distance errors in full arch impressions both in absolute values and in consistency for both measured distances. For the mean angulation errors, the Lava COS had the smallest errors between cylinders 1–2 and the largest errors between cylinders 1–3, although the absolute difference with the smallest mean value (iTero) was very small (0,0529°). An expected increase in distance and/or angular errors over the length of the arch due to an accumulation of registration errors of the patched 3D surfaces could be observed in this study design, but the effects were statistically not significant. Clinical relevance For making impressions of implant cases for digital workflows, the most accurate scanner with the scanning protocol that will ensure the most accurate digital impression should be used. In our study model that was the Lava COS with the high accuracy scanning protocol. PMID:22937030

Clinical observation of the application of autologous peripheral blood stem cell transplantation for the treatment of diabetic foot gangrene

PubMed Central

XU, SHI-MIN; LIANG, TING

2016-01-01

The aim of the present study was to investigate the optimal mobilization plan in autologous peripheral blood stem cell transplantation for the treatment of diabetic foot and to observe its clinical curative effect. A total of 127 patients with diabetic foot were treated with different doses of granulocyte colony stimulating factor (G-CSF) to mobilize their hematopoietic stem cells. Subsequently, the extracted stem cell suspension was injected into the ischemic lower extremities along the blood vessels in the areas presenting with pathological changes. Following the treatment, the intermittent claudication distance, skin temperature, ankle brachial index and pain scores of the patients were evaluated. In addition, the associations among the mobilization time, doses and peripheral blood CD34+ level were analyzed. The collection efficiency of the stem cells was associated with the dose of G-CSF and the mobilization time. Following the injection of the autologous peripheral blood stem cell suspension, the ischemic area of the patients was improved significantly. In conclusion, autologous peripheral blood stem cell transplantation can promote the establishment of collateral circulation in patients with diabetic foot, and the optimal time for gathering stem cells is closely correlated with the peripheral blood CD34+ level. PMID:26889255

Protrusion of a rod into the spinal canal 10 years after segmental lumbar spine surgery.

PubMed

Cai, Siyi; Kong, Xiangyi; Yan, Chengrui; Wang, Yipeng; Wan, Xueshuai; Zhang, Jialu; Qiu, Guixing; Yu, Keyi

2017-03-01

The objective of this article is to report an unusual case of a spinal rod that protruded into the spinal canal after lumbar spine surgery.Only 4 cases of spinal rod migration with protrusion into the spinal canal have been reported. This is the first report of a case involving the use of posterior low lumbar segmental instrumentation with a screw-rod system. The left side of the rod gradually migrated and finally protruded into the canal and compressed the cord.A 60-year-old woman presented with pain and numbness of the posterior aspect of the left leg after a long-distance walk. Intermittent claudication became worse, and she developed pain and numbness in the perineal region. An x-ray showed that the left side of a spinal rod among the segmental spinal instruments that had been placed 10 years previously had protruded into the spinal canal.We removed the rod and decompressed the canal at the level of L5-S1. The patient became totally asymptomatic.Rods used as spinal instrumentation have the possibility of protruding into the spinal canal and endangering the nervous system. Long-term follow-up with radiological examinations should be conducted upon completion of spinal operations conducting using instrumentation.

Optimal quantum error correcting codes from absolutely maximally entangled states

NASA Astrophysics Data System (ADS)

Raissi, Zahra; Gogolin, Christian; Riera, Arnau; Acín, Antonio

2018-02-01

Absolutely maximally entangled (AME) states are pure multi-partite generalizations of the bipartite maximally entangled states with the property that all reduced states of at most half the system size are in the maximally mixed state. AME states are of interest for multipartite teleportation and quantum secret sharing and have recently found new applications in the context of high-energy physics in toy models realizing the AdS/CFT-correspondence. We work out in detail the connection between AME states of minimal support and classical maximum distance separable (MDS) error correcting codes and, in particular, provide explicit closed form expressions for AME states of n parties with local dimension \

[«Man-in-the-barrel» syndrome: atypical manifestation of giant cell arteritis].

PubMed

Calle-Lopez, Y; Fernandez-Ramirez, A F; Franco-Dager, E; Gomez-Lopera, J G; Vanegas-Garcia, A L

2018-06-01

«Man-in-the-barrel» syndrome refers to diplegia of the upper extremities in which mobility of the head and lower limbs is preserved. Brachial plexitis that presents as «man-in-the-barrel» syndrome is an unusual manifestation of giant cell arteritis. We report a case of C5-C6 plexitis as part of the clinical features of a patient with giant cell arteritis. A 70-year-old male with a two-month history of weight loss, headache, facial pain and jaw claudication, associated with a persistent elevation of acute phase reactants and bilateral brachial plexopathy, with no evidence of neck or brain injuries or occult neoplasm and with negative autoimmunity tests. Results of the biopsy study of the temporal artery were compatible with giant cell arteritis, and the positron emission tomography scan revealed extensive vascular involvement of the aorta and its branches. Although the typical clinical manifestations of giant cell arteritis are headache, jaw claudication, loss of sight, constitutional symptoms and polymyalgia rheumatica, its presence must be suspected in patients over the age of 50 who manifest alterations affecting the peripheral nerve, including brachial diplegia with no other demonstrable cause.

[A 65-year-old man with history of claudication, palpable purpura and livedo reticularis].

PubMed

Braun, N; Kimmel, M; Grabner, A; Ott, G; Alscher, M D

2010-04-01

A 65-year-old man was admitted with history of claudication symptoms and painful skin lesions of the lower legs. Physical examination showed palpable purpura of the lower legs and livedo reticularis, most marked at the forefoot and toes. Computed tomography (CT) showed an aortic mass 2 cm above the bifurcation. This was treated after angiography with a covered stent. Biopsy of the skin lesions showed no sign of vasculitis and no cholesterol crystals. The patient was discharged and remained symptom-free for 9 months. He was readmitted at that time with recurrent complaints. CT revealed a subtotal stenosis of the aortic stent. A skin biopsy showed CD31-positive tumor cells in small arteries. Biopsy of a new osteolytic lesion in the ileum confirmed the diagnosis of angiosarcoma of the aorta. The patient decided in favor of palliative care and was discharged from the hospital. Primary tumors of the aorta, although they are rare, should be considered in the presence of an intravascular mass with stenosis to blood flow. A skin biopsy is easy to conduct and often leads to the final diagnosis. Georg Thieme Verlag KG Stuttgart. New York.

Absolute measurement of the extreme UV solar flux

NASA Technical Reports Server (NTRS)

Carlson, R. W.; Ogawa, H. S.; Judge, D. L.; Phillips, E.

1984-01-01

A windowless rare-gas ionization chamber has been developed to measure the absolute value of the solar extreme UV flux in the 50-575-A region. Successful results were obtained on a solar-pointing sounding rocket. The ionization chamber, operated in total absorption, is an inherently stable absolute detector of ionizing UV radiation and was designed to be independent of effects from secondary ionization and gas effusion. The net error of the measurement is + or - 7.3 percent, which is primarily due to residual outgassing in the instrument, other errors such as multiple ionization, photoelectron collection, and extrapolation to the zero atmospheric optical depth being small in comparison. For the day of the flight, Aug. 10, 1982, the solar irradiance (50-575 A), normalized to unit solar distance, was found to be 5.71 + or - 0.42 x 10 to the 10th photons per sq cm sec.

Determining distance to lightning strokes from a single station

NASA Technical Reports Server (NTRS)

Ruhnke, L. H. (Inventor)

1973-01-01

Apparatus is described for determining the distance to lightning strokes from a single station. The apparatus includes a first loop antenna system for sensing the magnetic field produced by the lightning which is filtered, square rooted, and fed into a peak voltage holding circuit. A second antenna is provided for sensing the electric field produced by the lightning which is fed into a filter, an absolute value meter, and to a peak voltage holding circuit. A multivibrator gates the magnetic and electric signals through the peak holding circuits to a ratio meter which produces a signal corresponding to the ratio between the magnetic component and the electric component. The amplitude of this signal is proportional to the distance from the apparatus to the lightning stroke.

The difference between two random mixed quantum states: exact and asymptotic spectral analysis

NASA Astrophysics Data System (ADS)

Mejía, José; Zapata, Camilo; Botero, Alonso

2017-01-01

We investigate the spectral statistics of the difference of two density matrices, each of which is independently obtained by partially tracing a random bipartite pure quantum state. We first show how a closed-form expression for the exact joint eigenvalue probability density function for arbitrary dimensions can be obtained from the joint probability density function of the diagonal elements of the difference matrix, which is straightforward to compute. Subsequently, we use standard results from free probability theory to derive a relatively simple analytic expression for the asymptotic eigenvalue density (AED) of the difference matrix ensemble, and using Carlson’s theorem, we obtain an expression for its absolute moments. These results allow us to quantify the typical asymptotic distance between the two random mixed states using various distance measures; in particular, we obtain the almost sure asymptotic behavior of the operator norm distance and the trace distance.

The paradoxical moon illusions.

PubMed

Gilinsky, A S

1980-02-01

An adaptation theory of visual space is developed and applied to the data of a variety of studies of visual space perception. By distinguishing between the perceived distance of an object and that of the background or sky, the theory resolves the paradox of the moon illusions and relates both perceived size and perceived distance of the moon to the absolute level of spatial adaptation. The theory assumes that visual space expands or contracts in adjustment to changes in the sensory indicators of depth and provides a measure, A, of this adaptation-level. Changes in A have two effects--one on perceived size, one on perceived distance. Since A varies systematically as a function of angle of regard, availability of cues, and the total space-value, A is a measure of the moon illusions, and a practical index of individual differences by pilots and astronauts in the perception of the size and distance of objects on the ground and in the air.

The Hubble diagram in V for supernovae of Type Ia and the value of H(0) therefrom

NASA Technical Reports Server (NTRS)

Sandage, Allan; Tammann, G. A.

1993-01-01

The Hubble diagram for Type I supernovae is derived in V and is summarized from the literature in B and in m(pg). The ridge line equation of the diagram in V and the calibration of the absolute magnitudes at maximum are presented. The intrinsic (B - V) color at B maximum light is 0.09 +/- 0.04 mag. The Virgo Cluster distance is derived and found to be 23.9 +/- 2.4 Mpc. This Virgo distance gives the cosmic value of the Hubble constant to be H(0) = 47 +/- 5 km/sec per Mpc.

Red clump stars and Gaia: calibration of the standard candle using a hierarchical probabilistic model

NASA Astrophysics Data System (ADS)

Hawkins, Keith; Leistedt, Boris; Bovy, Jo; Hogg, David W.

2017-10-01

Distances to individual stars in our own Galaxy are critical in order to piece together the nature of its velocity and spatial structure. Core helium burning red clump (RC) stars have similar luminosities, are abundant throughout the Galaxy and thus constitute good standard candles. We build a hierarchical probabilistic model to quantify the quality of RC stars as standard candles using parallax measurements from the first Gaia data release. A unique aspect of our methodology is to fully account for (and marginalize over) parallax, photometry and dust correction uncertainties, which lead to more robust results than standard approaches. We determine the absolute magnitude and intrinsic dispersion of the RC in 2MASS bands J, H, Ks, Gaia G band and WISE bands W1, W2, W3 and W4. We find that the absolute magnitude of the RC is -1.61 ± 0.01 (in Ks), +0.44 ± 0.01 (in G), -0.93 ± 0.01 (in J), -1.46 ± 0.01 (in H), -1.68 ± 0.02 (in W1), -1.69 ± 0.02 (in W2), -1.67 ± 0.02 (in W3) and -1.76 ± 0.01 mag (in W4). The mean intrinsic dispersion is ˜0.17 ± 0.03 mag across all bands (yielding a typical distance precision of ˜8 per cent). Thus RC stars are reliable and precise standard candles. In addition, we have also re-calibrated the zero-point of the absolute magnitude of the RC in each band, which provides a benchmark for future studies to estimate distances to RC stars. Finally, the parallax error shrinkage in the hierarchical model outlined in this work can be used to obtain more precise parallaxes than Gaia for the most distant RC stars across the Galaxy.

The interactive role of income (material position) and income rank (psychosocial position) in psychological distress: a 9-year longitudinal study of 30,000 UK parents.

PubMed

Garratt, Elisabeth A; Chandola, Tarani; Purdam, Kingsley; Wood, Alex M

2016-10-01

Parents face an increased risk of psychological distress compared with adults without children, and families with children also have lower average household incomes. Past research suggests that absolute income (material position) and income status (psychosocial position) influence psychological distress, but their combined effects on changes in psychological distress have not been examined. Whether absolute income interacts with income status to influence psychological distress are also key questions. We used fixed-effects panel models to examine longitudinal associations between psychological distress (measured on the Kessler scale) and absolute income, distance from the regional mean income, and regional income rank (a proxy for status) using data from 29,107 parents included in the UK Millennium Cohort Study (2003-2012). Psychological distress was determined by an interaction between absolute income and income rank: higher absolute income was associated with lower psychological distress across the income spectrum, while the benefits of higher income rank were evident only in the highest income parents. Parents' psychological distress was, therefore, determined by a combination of income-related material and psychosocial factors. Both material and psychosocial factors contribute to well-being. Higher absolute incomes were associated with lower psychological distress across the income spectrum, demonstrating the importance of material factors. Conversely, income status was associated with psychological distress only at higher absolute incomes, suggesting that psychosocial factors are more relevant to distress in more advantaged, higher income parents. Clinical interventions could, therefore, consider both the material and psychosocial impacts of income on psychological distress.

Suppression of Systematic Errors of Electronic Distance Meters for Measurement of Short Distances

PubMed Central

Braun, Jaroslav; Štroner, Martin; Urban, Rudolf; Dvořáček, Filip

2015-01-01

In modern industrial geodesy, high demands are placed on the final accuracy, with expectations currently falling below 1 mm. The measurement methodology and surveying instruments used have to be adjusted to meet these stringent requirements, especially the total stations as the most often used instruments. A standard deviation of the measured distance is the accuracy parameter, commonly between 1 and 2 mm. This parameter is often discussed in conjunction with the determination of the real accuracy of measurements at very short distances (5–50 m) because it is generally known that this accuracy cannot be increased by simply repeating the measurement because a considerable part of the error is systematic. This article describes the detailed testing of electronic distance meters to determine the absolute size of their systematic errors, their stability over time, their repeatability and the real accuracy of their distance measurement. Twenty instruments (total stations) have been tested, and more than 60,000 distances in total were measured to determine the accuracy and precision parameters of the distance meters. Based on the experiments’ results, calibration procedures were designed, including a special correction function for each instrument, whose usage reduces the standard deviation of the measurement of distance by at least 50%. PMID:26258777

Suppression of Systematic Errors of Electronic Distance Meters for Measurement of Short Distances.

PubMed

Braun, Jaroslav; Štroner, Martin; Urban, Rudolf; Dvoček, Filip

2015-08-06

In modern industrial geodesy, high demands are placed on the final accuracy, with expectations currently falling below 1 mm. The measurement methodology and surveying instruments used have to be adjusted to meet these stringent requirements, especially the total stations as the most often used instruments. A standard deviation of the measured distance is the accuracy parameter, commonly between 1 and 2 mm. This parameter is often discussed in conjunction with the determination of the real accuracy of measurements at very short distances (5-50 m) because it is generally known that this accuracy cannot be increased by simply repeating the measurement because a considerable part of the error is systematic. This article describes the detailed testing of electronic distance meters to determine the absolute size of their systematic errors, their stability over time, their repeatability and the real accuracy of their distance measurement. Twenty instruments (total stations) have been tested, and more than 60,000 distances in total were measured to determine the accuracy and precision parameters of the distance meters. Based on the experiments' results, calibration procedures were designed, including a special correction function for each instrument, whose usage reduces the standard deviation of the measurement of distance by at least 50%.

Isolated popliteal artery occlusion in the young.

PubMed

Khoda, J; Lantsberg, L; Sebbag, G

1992-01-01

Three young patients with an isolated popliteal artery occlusion are presented, two with severe claudication and the third with a critical ischaemic foot. The work-up of these patients leads to certain aetiologic possibilities: microtrauma, smoking and contraceptive pills. Two of our patients underwent thromboembolectomy, the third managed conservatively. The follow-up was between six months and seven years and up to now all three patients remain well.

Shifting paradigms in the treatment of lower extremity vascular disease: a report of 1000 percutaneous interventions.

PubMed

DeRubertis, Brian G; Faries, Peter L; McKinsey, James F; Chaer, Rabih A; Pierce, Matthew; Karwowski, John; Weinberg, Alan; Nowygrod, Roman; Morrissey, Nicholas J; Bush, Harry L; Kent, K Craig

2007-09-01

Catheter-based revascularization has emerged as an alternative to surgical bypass for lower extremity vascular disease and is a frequently used tool in the armamentarium of the vascular surgeon. In this study we report contemporary outcomes of 1000 percutaneous infra-inguinal interventions performed by a single vascular surgery division. We evaluated a prospectively maintained database of 1000 consecutive percutaneous infra-inguinal interventions between 2001 and 2006 performed for claudication (46.3%) or limb-threatening ischemia (52.7%; rest pain in 27.7% and tissue loss in 72.3%). Treatments included angioplasty with or without stenting, laser angioplasty, and atherectomy of the femoral, popliteal, and tibial vessels. Mean age was 71.4 years and 57.3% were male; comorbidities included hypertension (84%), coronary artery disease (51%), diabetes (58%), tobacco use (52%), and chronic renal insufficiency (39%). Overall 30-day mortality was 0.5%. Two-year primary and secondary patencies and rate of amputation were 62.4%, 79.3%, and 0.5%, respectively, for patients with claudication. Two-year primary and secondary patencies and limb salvage rates were 37.4%, 55.4%, and 79.3% for patients with limb-threatening ischemia. By multivariable Cox PH modeling, limb-threat as procedural indication (P < 0.0001), diabetes (P = 0.003), hypercholesterolemia (P = 0.001), coronary artery disease (P = 0.047), and Transatlantic Inter-Society Consensus D lesion complexity (P = 0.050) were independent predictors of recurrent disease. For patients that developed recurrent disease, 7.5% required no further intervention, 60.3% underwent successful percutaneous reintervention, 11.7% underwent bypass and 20.5% underwent amputation. Patency rates were identical for the initial procedure and subsequent reinterventions (P = 0.97). Percutaneous therapy for peripheral vascular disease is associated with minimal mortality and can achieve 2-year secondary patency rates of nearly 80% in patients with claudication. Although patency is diminished in patients with limb-threat, limb-salvage rates remain reasonable at close to 80% at 2 years. Percutaneous infra-inguinal revascularization carries a low risk of morbidity and mortality, and should be considered first-line therapy in patients with chronic lower extremity ischemia.

Plasma viscosity increase with progression of peripheral arterial atherosclerotic disease.

PubMed

Poredos, P; Zizek, B

1996-03-01

Increased blood and plasma viscosity has been described in patients with coronary and peripheral arterial disease. However, the relation of viscosity to the extent of arterial wall deterioration--the most important determinant of clinical manifestation and prognosis of the disease--is not well known. Therefore, the authors studied plasma viscosity as one of the major determinants of blood viscosity in patients with different stages of arterial disease of lower limbs (according to Fontaine) and its relation to the presence of some risk factors of atherosclerosis. The study encompassed four groups of subjects: 19 healthy volunteers (group A), 18 patients with intermittent claudication up to 200 m (stage II; group B), 15 patients with critical ischemia of lower limbs (stage III and IV; group C), and 16 patients with recanalization procedures on peripheral arteries. Venous blood samples were collected from an antecubital vein without stasis for the determination of plasma viscosity (with a rotational capillary microviscometer, PAAR), fibrinogen, total cholesterol, alpha-2-macroglobulin, and glucose concentrations. In patients with recanalization procedure local plasma viscosity was also determined from blood samples taken from a vein on the dorsum of the foot. Plasma viscosity was most significantly elevated in the patients with critical ischemia (1.78 mPa.sec) and was significantly higher than in the claudicants (1.68 mPa.sec), and the claudicants also had significantly higher viscosity than the controls (1.58 mPa.sec). In patients in whom a recanalization procedure was performed, no differences in systemic and local plasma viscosity were detected, neither before nor after recanalization of the diseased artery. In all groups plasma viscosity was correlated with fibrinogen concentration (r=0.70, P < 0.01) and total cholesterol concentration (r=0.24, P < 0.05), but in group C (critical ischemia) plasma viscosity was most closely linked to the concentration of alpha-2-macroglobulin (r=0.78, P < 0.01). These results indicate that in patients with peripheral arterial disease plasma viscosity increases with the progression of the atherosclerotic process and is correlated with the clinical stages of the disease.

Long-term safety of cilostazol in patients with peripheral artery disease: the CASTLE study (Cilostazol: A Study in Long-term Effects).

PubMed

Hiatt, William R; Money, Samuel R; Brass, Eric P

2008-02-01

Cilostazol, a phosphodiesterase III inhibitor, is indicated to treat the symptoms of intermittent claudication and increase walking distance in patients with peripheral arterial disease (PAD). At the time of approval, the United States Food and Drug Administration required an additional long-term safety study to evaluate the effect cilostazol on mortality. A total of 1899 subjects with a clinical diagnosis of PAD and symptoms of claudication were screened for participation in a randomized, double-blinded, placebo-controlled safety study of cilostazol. The intent-to-treat (ITT) population, which was the primary analysis (n = 1435), was defined as all randomized patients who received at least one dose of study medication and included patients who were followed up >30 days after discontinuation of study drug. A total of 717 patients received cilostazol and 718 received placebo. Cilostazol was administered at a primary dose of 100 mg twice daily. The dose could be reduced to 50 mg twice daily if patients experienced an adverse event that might have been drug related. Long-term adherence to study medication was poor, with >60% of participants discontinuing therapy by 36 months. The mortality analysis therefore focused on deaths during the period on-treatment, defined as the period during which the study drug was taken plus a 30-day follow-up period after dosing. Total patient-years of exposure were 1046 on-treatment for cilostazol and 1090 for placebo. On-treatment, there were 18 deaths on cilostazol and 19 deaths on placebo for a hazard ratio of 0.99 (95% confidence interval [CI], 0.52-1.88). Cardiovascular deaths on-treatment occurred in 14 patients on cilostazol and 14 on placebo. In the full ITT population at 36 months, there were 101 deaths, 49 on cilostazol and 52 on placebo, with hazard ratio of 0.94 (95% CI, 0.64-1.39). Thus, most deaths occurred >30 days after study drug discontinuation. Serious bleeding events affected 18 patients taking cilostazol in the on-treatment population and 22 taking placebo. The rates of bleeding events were similar in patients who used aspirin, aspirin plus clopidogrel, or anticoagulants at anytime during the course of the study This long-term study demonstrated no safety signal for cilostazol on all-cause or cardiovascular mortality. The study, however, was underpowered to detect a small adverse impact of cilostazol on mortality (hazard ratio upper bound of the 95% CI was 1.88 in the on-treatment population). Serious bleeding events appeared not to be increased by cilostazol.

Auditory distance perception in humans: a review of cues, development, neuronal bases, and effects of sensory loss.

PubMed

Kolarik, Andrew J; Moore, Brian C J; Zahorik, Pavel; Cirstea, Silvia; Pardhan, Shahina

2016-02-01

Auditory distance perception plays a major role in spatial awareness, enabling location of objects and avoidance of obstacles in the environment. However, it remains under-researched relative to studies of the directional aspect of sound localization. This review focuses on the following four aspects of auditory distance perception: cue processing, development, consequences of visual and auditory loss, and neurological bases. The several auditory distance cues vary in their effective ranges in peripersonal and extrapersonal space. The primary cues are sound level, reverberation, and frequency. Nonperceptual factors, including the importance of the auditory event to the listener, also can affect perceived distance. Basic internal representations of auditory distance emerge at approximately 6 months of age in humans. Although visual information plays an important role in calibrating auditory space, sensorimotor contingencies can be used for calibration when vision is unavailable. Blind individuals often manifest supranormal abilities to judge relative distance but show a deficit in absolute distance judgments. Following hearing loss, the use of auditory level as a distance cue remains robust, while the reverberation cue becomes less effective. Previous studies have not found evidence that hearing-aid processing affects perceived auditory distance. Studies investigating the brain areas involved in processing different acoustic distance cues are described. Finally, suggestions are given for further research on auditory distance perception, including broader investigation of how background noise and multiple sound sources affect perceived auditory distance for those with sensory loss.

Absolute calibration of Doppler coherence imaging velocity images

NASA Astrophysics Data System (ADS)

Samuell, C. M.; Allen, S. L.; Meyer, W. H.; Howard, J.

2017-08-01

A new technique has been developed for absolutely calibrating a Doppler Coherence Imaging Spectroscopy interferometer for measuring plasma ion and neutral velocities. An optical model of the interferometer is used to generate zero-velocity reference images for the plasma spectral line of interest from a calibration source some spectral distance away. Validation of this technique using a tunable diode laser demonstrated an accuracy better than 0.2 km/s over an extrapolation range of 3.5 nm; a two order of magnitude improvement over linear approaches. While a well-characterized and very stable interferometer is required, this technique opens up the possibility of calibrated velocity measurements in difficult viewing geometries and for complex spectral line-shapes.

Analisis fotometrico del cumulo abierto NGC 6611

NASA Astrophysics Data System (ADS)

Suarez Nunez, Johanna

2007-08-01

Matlab programs were designed to apply differential aperture photometry. Two images were taken with a charge-couple device ( CCD ) in the visible V and blue filters, to calculate physical parameters (the flux( f ), the apparent magnitude ( m V ) and its reddening corrected value ( V 0 ), color index ( B- V ) and ( B-V ) 0 , the log of effective temperature (log T eff ), the absolute magnitude ( M V ), the bolometric magnitude ( M B ) & log(L [low *] /[Special characters omitted.] )) of each studied star pertaining to the open cluster NGC 6611. Upon obtaining the parameters, the color-magnitude diagram was graphed and by fitting to the main sequence, the distance modulus and thus the distance to the cluster was found. The stars were assumed to be at the same distance and born at approximately the same moment.

Experts Appear to Use Angle of Elevation Information in Basketball Shooting

ERIC Educational Resources Information Center

de Oliveira, Rita Ferraz; Oudejans, Raoul R. D.; Beek, Peter J.

2009-01-01

For successful basketball shooting, players must use information about the location of the basket relative to themselves. In this study, the authors examined to what extent shooting performance depends on the absolute distance to the basket ("m") and the angle of elevation (alpha). In Experiment 1, expert players took jump shots under different…

Russell, Henry Norris (1877-1957)

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Astronomer, born in Oyster Bay, NY, spent nearly all his life working at Princeton University. He spectroscopically studied eclipsing binary stars to determine the masses of their component stars. At first collaborating with the British astronomer Hinks at Cambridge, he started to measure stellar parallaxes and, plotting the absolute magnitudes of stars whose distance he had thus measured, agains...

A Proposal for a Variation on the Axioms of Classical Geometry

ERIC Educational Resources Information Center

Schellenberg, Bjorn

2010-01-01

A set of axioms for classical absolute geometry is proposed that is accessible to students new to axioms. The metric axioms adopted are the ruler axiom, triangle inequality and the bisector axiom. Angle measure is derived from distance, and all properties needed to establish a consistent system are derived. In particular, the SAS congruence…

Automatic segmentation of right ventricular ultrasound images using sparse matrix transform and a level set

NASA Astrophysics Data System (ADS)

Qin, Xulei; Cong, Zhibin; Fei, Baowei

2013-11-01

An automatic segmentation framework is proposed to segment the right ventricle (RV) in echocardiographic images. The method can automatically segment both epicardial and endocardial boundaries from a continuous echocardiography series by combining sparse matrix transform, a training model, and a localized region-based level set. First, the sparse matrix transform extracts main motion regions of the myocardium as eigen-images by analyzing the statistical information of the images. Second, an RV training model is registered to the eigen-images in order to locate the position of the RV. Third, the training model is adjusted and then serves as an optimized initialization for the segmentation of each image. Finally, based on the initializations, a localized, region-based level set algorithm is applied to segment both epicardial and endocardial boundaries in each echocardiograph. Three evaluation methods were used to validate the performance of the segmentation framework. The Dice coefficient measures the overall agreement between the manual and automatic segmentation. The absolute distance and the Hausdorff distance between the boundaries from manual and automatic segmentation were used to measure the accuracy of the segmentation. Ultrasound images of human subjects were used for validation. For the epicardial and endocardial boundaries, the Dice coefficients were 90.8 ± 1.7% and 87.3 ± 1.9%, the absolute distances were 2.0 ± 0.42 mm and 1.79 ± 0.45 mm, and the Hausdorff distances were 6.86 ± 1.71 mm and 7.02 ± 1.17 mm, respectively. The automatic segmentation method based on a sparse matrix transform and level set can provide a useful tool for quantitative cardiac imaging.

A NEW METHOD TO QUANTIFY AND REDUCE THE NET PROJECTION ERROR IN WHOLE-SOLAR-ACTIVE-REGION PARAMETERS MEASURED FROM VECTOR MAGNETOGRAMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Falconer, David A.; Tiwari, Sanjiv K.; Moore, Ronald L.

Projection errors limit the use of vector magnetograms of active regions (ARs) far from the disk center. In this Letter, for ARs observed up to 60° from the disk center, we demonstrate a method for measuring and reducing the projection error in the magnitude of any whole-AR parameter that is derived from a vector magnetogram that has been deprojected to the disk center. The method assumes that the center-to-limb curve of the average of the parameter’s absolute values, measured from the disk passage of a large number of ARs and normalized to each AR’s absolute value of the parameter atmore » central meridian, gives the average fractional projection error at each radial distance from the disk center. To demonstrate the method, we use a large set of large-flux ARs and apply the method to a whole-AR parameter that is among the simplest to measure: whole-AR magnetic flux. We measure 30,845 SDO /Helioseismic and Magnetic Imager vector magnetograms covering the disk passage of 272 large-flux ARs, each having whole-AR flux >10{sup 22} Mx. We obtain the center-to-limb radial-distance run of the average projection error in measured whole-AR flux from a Chebyshev fit to the radial-distance plot of the 30,845 normalized measured values. The average projection error in the measured whole-AR flux of an AR at a given radial distance is removed by multiplying the measured flux by the correction factor given by the fit. The correction is important for both the study of the evolution of ARs and for improving the accuracy of forecasts of an AR’s major flare/coronal mass ejection productivity.« less

Very Fast Estimation of Epicentral Distance and Magnitude from a Single Three Component Seismic Station Using Machine Learning Techniques

NASA Astrophysics Data System (ADS)

Ochoa Gutierrez, L. H.; Niño Vasquez, L. F.; Vargas-Jimenez, C. A.

2012-12-01

To minimize adverse effects originated by high magnitude earthquakes, early warning has become a powerful tool to anticipate a seismic wave arrival to an specific location and lets to bring people and government agencies opportune information to initiate a fast response. To do this, a very fast and accurate characterization of the event must be done but this process is often made using seismograms recorded in at least 4 stations where processing time is usually greater than the wave travel time to the interest area, mainly in coarse networks. A faster process can be done if only one three component seismic station is used that is the closest unsaturated station respect to the epicenter. Here we present a Support Vector Regression algorithm which calculates Magnitude and Epicentral Distance using only 5 seconds of signal since P wave onset. This algorithm was trained with 36 records of historical earthquakes where the input were regression parameters of an exponential function estimated by least squares, corresponding to the waveform envelope and the maximum value of the observed waveform for each component in one single station. A 10 fold Cross Validation was applied for a Normalized Polynomial Kernel obtaining the mean absolute error for different exponents and complexity parameters. Magnitude could be estimated with 0.16 of mean absolute error and the distance with an error of 7.5 km for distances within 60 to 120 km. This kind of algorithm is easy to implement in hardware and can be used directly in the field station to make possible the broadcast of estimations of this values to generate fast decisions at seismological control centers, increasing the possibility to have an effective reactiontribute and Descriptors calculator for SVR model training and test

Pilot behaviors in the face of adverse weather: A new look at an old problem.

PubMed

Batt, Richard; O'Hare, David

2005-06-01

Weather-related general aviation accidents remain one of the most significant causes for concern in aviation safety. Previous studies have typically compared accident and non-accident cases. In contrast, the current study does not concentrate on occurrence outcome. Instead, the emphasis is on the different behaviors that pilots exhibit in the face of adverse weather and, by inference, on the decision-making processes that underlie those behaviors. This study compares three weather-related behaviors that reflect different levels of risk: visual flight rules flight into instrument meteorological conditions ('VFR into IMC'); precautionary landing; and other significant weather avoidance actions. Occurrence data (n=491) were drawn from the Australian Transport Safety Bureau database of aviation occurrences, and included weather-related accidents, incidents, and 'normal operationsd.' There were few significant differences between the three weather-related behavior groups in terms of pilot demographics, aircraft characteristics, geographic or environmental factors, or absolute flight distances. The pattern of relative flight distances (a psychological construct) was markedly different for the three groups, with pilots in the weather avoidance group being distinguished by taking timely action. The relative distance results suggest that the mid-point of the flight can be a 'psychological turning point' for pilots, irrespective of the absolute flight distance involved. Hence, pilots' behavior was sometimes influenced by psychological factors not related to any particular operational aspect of the flight. The results of the weather avoidance group indicate that a safe pilot is a proactive pilot. Dealing with adverse weather is not a one-off decision but a continually evolving process. This aspect is discussed in terms of the concept of 'mindfulness'.

THE VMC SURVEY. XIX. CLASSICAL CEPHEIDS IN THE SMALL MAGELLANIC CLOUD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ripepi, V.; Marconi, M.; Moretti, M. I.

2016-06-01

The “VISTA near-infrared YJK {sub s}  survey of the Magellanic Clouds System” (VMC) is collecting deep K {sub s}-band time-series photometry of pulsating variable stars hosted by the two Magellanic Clouds and their connecting Bridge. In this paper, we present Y , J , K {sub s} light curves for a sample of 4172 Small Magellanic Cloud (SMC) Classical Cepheids (CCs). These data, complemented with literature V values, allowed us to construct a variety of period–luminosity (PL), period–luminosity–color (PLC), and period–Wesenheit (PW) relationships, which are valid for Fundamental (F), First Overtone (FO), and Second Overtone (SO) pulsators. The relations involvingmore » the V , J , K {sub s} bands are in agreement with their counterparts in the literature. As for the Y band, to our knowledge, we present the first CC PL, PW, and PLC relations ever derived using this filter. We also present the first near–infrared PL, PW, and PLC relations for SO pulsators to date. We used PW( V , K {sub s}) to estimate the relative SMC–LMC distance and, in turn, the absolute distance to the SMC. For the former quantity, we find a value of Δ μ  = 0.55 ± 0.04 mag, which is in rather good agreement with other evaluations based on CCs, but significantly larger than the results obtained from older population II distance indicators. This discrepancy might be due to the different geometric distributions of young and old tracers in both Clouds. As for the absolute distance to the SMC, our best estimates are μ {sub SMC} = 19.01 ± 0.05 mag and μ {sub SMC} = 19.04 ± 0.06 mag, based on two distance measurements to the LMC which rely on accurate CC and eclipsing Cepheid binary data, respectively.« less

The Araucaria project. The distance to the small Magellanic Cloud from late-type eclipsing binaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graczyk, Dariusz; Pietrzyński, Grzegorz; Gieren, Wolfgang

2014-01-01

We present a distance determination to the Small Magellanic Cloud (SMC) based on an analysis of four detached, long-period, late-type eclipsing binaries discovered by the Optical Gravitational Lensing Experiment (OGLE) survey. The components of the binaries show negligible intrinsic variability. A consistent set of stellar parameters was derived with low statistical and systematic uncertainty. The absolute dimensions of the stars are calculated with a precision of better than 3%. The surface brightness-infrared color relation was used to derive the distance to each binary. The four systems clump around a distance modulus of (m – M) = 18.99 with a dispersionmore » of only 0.05 mag. Combining these results with the distance published by Graczyk et al. for the eclipsing binary OGLE SMC113.3 4007, we obtain a mean distance modulus to the SMC of 18.965 ± 0.025 (stat.) ± 0.048 (syst.) mag. This corresponds to a distance of 62.1 ± 1.9 kpc, where the error includes both uncertainties. Taking into account other recent published determinations of the SMC distance we calculated the distance modulus difference between the SMC and the Large Magellanic Cloud equal to 0.458 ± 0.068 mag. Finally, we advocate μ{sub SMC} = 18.95 ± 0.07 as a new 'canonical' value of the distance modulus to this galaxy.« less

Distance M-Me: A novel parameter having significant potential as a predictor of mandibular growth.

PubMed

Jain, Parul; Kaul, Rahul; Mukhopadhyay, Santanu; Saha, Subrata; Sarkar, Subir

2017-01-01

The purpose of the present study was to investigate the relationship of the measured distance between two mandibular points (distance M-Me) to chronological age and to find out whether the absolute values of distance M-Me could be classified age-wise into a unique range, which could be directly read for predicting the stage of mandibular growth. The study sample consists of lateral cephalometric records of 65 patients (34 females and 31 males; age range: 6-21 years). Chronological age was calculated in decimal years. Lateral cephalograms were assessed by two independent examiners. Points M and Me were located on the lateral cephalograms, and linear distance between them was measured. Pearson product-moment correlation coefficients showed a high correlation between chronological age and distance M-Me (0.746 for females and 0.869 for males, p < 0.01). When the values of distance M-Me were compared with chronological age, it was possible to make four age groups (for females and males separately), where each group showed a unique range of value for distance M-Me. The values increased with increasing age. Increase in value of distance M-Me with age, showing reduced individual variation, depicts a well-conserved linear dimension. Values of distance M-Me can be directly read for predicting the stage of mandibular growth and can be used as a valuable adjunct or substitute to chronological age.

Treatment of cells with alkaline borate buffer extends the capability of interphase FISH mapping.

PubMed

Yokota, H; van den Engh, G; Mostert, M; Trask, B J

1995-01-20

Interphase fluorescence in situ hybridization (FISH) has been shown to be a means to map DNA sequences relative to each other in the 100 kb to 1-2 Mb genomic-separation range. At distances below 0.1 Mb, probe sites are infrequently resolved in interphase chromatin. In the 0.1- to 1-Mb range, interphase chromatin can be modeled as a freely flexible chain. The mean square interphase distance between two probes is proportional to the genomic separation between the probes on the linear DNA molecule. Above 1-2 Mb, the relationship between interphase distance and genomic separation changes abruptly and appears to level off. We have used alkaline-borate treatment to expand the capability of interphase FISH mapping. We show here that alkaline-borate treatment increases nuclear diameter, the interphase distance between probes on homologous chromosomes, and the distance between probes on the same chromosome. We also show that the mean square distance between hybridization sites in borate-treated nuclei is proportional to genomic separation up to 4 Mb. Thus, alkaline-borate treatment enhances the capability of interphase FISH mapping by increasing the absolute distance between probes and extending the range of the simple relationship between interphase distance and genomic separation.

Treatment of cells with alkaline borate buffer extends the capability of interphase FISH mapping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yokota, H.; Van Den Engh, G.; Mostert, M.

1995-01-20

Interphase fluorescence in situ hybridization (FISH) has been shown to be a means to map DNA sequences relative to each other in the 100 kb to 1-2 Mb genomic-separation range. At distances below 0.1 Mb, probe sites are infrequently resolved in interphase chromatin. In the 0.1- to 1-Mb range, interphase chromatin can be modeled as a freely flexible chain. The mean square interphase distance between two probes is proportional to the genomic separation between the probes on the linear DNA molecule. Above 1-2 Mb, the relationship between interphase distance and genomic separation changes abruptly and appears to level off. Wemore » have used alkaline-borate treatment to expand the capability of interphase FISH mapping. We show here that alkaline-borate treatment increases nuclear diameter, the interphase distance between probes on homologous chromosomes, and the distance between probes on the same chromosome. We also show that the mean square distance between hybridization sites in borate-treated nuclei is proportional to genomic separation up to 4 Mb. Thus, alkaline-borate treatment enhances the capability of interphase FISH mapping by increasing the absolute distance between probes and extending the range of the simple relationship between interphase distance and genomic separation. 31 refs., 5 figs.« less

Iatrogenic Aorto-Cisterna Chyli Fistula During Percutaneous Balloon Aortoplasty in a Patient with Takayasu's Arteritis: A Case Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, Hye Sun; Shin, Sung Wook, E-mail: swshin@smc.samsung.co.kr; Kim, Eun Hui

2007-04-15

We present a case of iatrogenic aorto-cisterna chyli fistula that developed during percutaneous transluminal aortoplasty in a 16-year old girl with Takayasu's arteritis. The aorto-cisterna chyli fistula was angiographically confirmed and treated using a stent-graft, which successfully occluded the fistula. Her claudication then improved, although follow-up CT angiography at 10 months revealed mild recurrent aortic stenosis.

Post-AGB Stars in Nearby Galaxies as Calibrators for HST

NASA Technical Reports Server (NTRS)

Bond, Howard E.

2003-01-01

This report summarizes activities carried out with support from the NASA Ultraviolet, Visible, and Gravitational Astrophysics Research and Analysis Program under Grant NAG 5-6821. The Principal Investigator is Howard E. Bond (Space Telescope Science Institute). STScI Postdoctoral Associates Laura K. Fullton (1998), David Alves (1998-2001), and Michael Siegel (2001) were partially supported by this grant. The aim of the program is to calibrate the absolute magnitudes of post-asymptotic- giant-branch (post-AGB or PAGB) stars, which we believe will be an excellent new "standard candle" for measuring extragalactic distances. The argument is that, in old populations, the stars that are evolving through the PAGB region of the HR diagram arise from only a single main-sequence turnoff mass. In addition, theoretical PAGB evolutionary tracks show that they evolve through this region at constant luminosity; hence the PAGB stars should have an extremely narrow luminosity function. Moreover, as the PAGB stars evolve through spectral types F and A (en route from the AGB to hot stellar remnants and white dwarfs), they have the highest luminosities attained by old stars (both bolometrically and in the visual band). Finally, PAGB stars of these spectral types are very easily identified. because of their large Balmer jumps, which are due to their very low surface gravities. Our approach is first to identify PAGB stars in Milky Way globular clusters and in other Local Group galaxies, which are at known distances, and thus to measure accurate absolute magnitudes for the PAGB stars. With this Milky Way and Local Group luminosity calibration, we will then be in a position to find PAGB stars in more distant galaxies from the ground, and ultimately from the Hubble Space Telescope. and thus derive distances. These PAGB stars are, as noted above, the visually brightest members of Population II, and hence will allow distance measurements to galaxies that do not contain Cepheids, such as elliptical galaxies, as well as distances to spirals using PAGB stars in their halos. Moreover, the method is entirely independent of Cepheids. and thus provides a direct test of the Cepheid distance scale. The program will also provide information on the evolutionary lifetimes of PAGB stars.

Debiased estimates for NEO orbits, absolute magnitudes, and source regions

NASA Astrophysics Data System (ADS)

Granvik, Mikael; Morbidelli, Alessandro; Jedicke, Robert; Bolin, Bryce T.; Bottke, William; Beshore, Edward C.; Vokrouhlicky, David; Nesvorny, David; Michel, Patrick

2017-10-01

The debiased absolute-magnitude and orbit distributions as well as source regions for near-Earth objects (NEOs) provide a fundamental frame of reference for studies on individual NEOs as well as on more complex population-level questions. We present a new four-dimensional model of the NEO population that describes debiased steady-state distributions of semimajor axis (a), eccentricity (e), inclination (i), and absolute magnitude (H). We calibrate the model using NEO detections by the 703 and G96 stations of the Catalina Sky Survey (CSS) during 2005-2012 corresponding to objects with 17

Measurement of the "safe zone" and the "dangerous zone" for the screw placement on the quadrilateral surface in the treatment of pelvic and acetabular fractures with Stoppa approach by computational 3D technology.

PubMed

Zhang, Sheng; Su, Wanhan; Luo, Qiang; Leung, Frankie; Chen, Bin

2014-01-01

This study is aimed at definition of the safe and dangerous zone for screw placement with Stoppa approach for rapid identification during operation and a new way for the studies on the "safe zone." Pelvic CT data of 84 human subjects were recruited to reconstruct the three-dimensional (3D) models. The distances between the edges of the "safe zone," "dangerous zone," and specific anatomic landmarks such as the obturator canal and the pelvic brim were precisely measured, respectively. The results show that the absolute "dangerous zone" was from the pelvic brim to 3.07 cm below it and within 2.86 cm of the obturator canal, while the region 3.56 cm below the pelvic brim or 3.85 cm away from the obturator canal was the absolute "safe zone" for screw placement. The region between the absolute "safe zone" and the absolute "dangerous zone" was the relatively "dangerous zone." As a conclusion, application of computer-assisted 3D modeling techniques aids in the precise measurement of "safe zone" and "dangerous zone" in combination with Stoppa incision. It was not recommended to place screws on the absolute dangerous zone, while, for the relatively "dangerous zone," it depends on the individual variations in bony anatomy and the fracture type.

The Near-infrared Tip of the Red Giant Branch. II. An Absolute Calibration in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Hoyt, Taylor J.; Freedman, Wendy L.; Madore, Barry F.; Seibert, Mark; Beaton, Rachael L.; Hatt, Dylan; Jang, In Sung; Lee, Myung Gyoon; Monson, Andrew J.; Rich, Jeffrey A.

2018-05-01

We present a new empirical JHK absolute calibration of the tip of the red giant branch (TRGB) in the Large Magellanic Cloud (LMC). We use published data from the extensive Near-Infrared Synoptic Survey containing 3.5 million stars, 65,000 of which are red giants that fall within one magnitude of the TRGB. Adopting the TRGB slopes from a companion study of the isolated dwarf galaxy IC 1613, as well as an LMC distance modulus of μ 0 = 18.49 mag from (geometric) detached eclipsing binaries, we derive absolute JHK zero points for the near-infrared TRGB. For a comparison with measurements in the bar alone, we apply the calibrated JHK TRGB to a 500 deg2 area of the 2MASS survey. The TRGB reveals the 3D structure of the LMC with a tilt in the direction perpendicular to the major axis of the bar, which is in agreement with previous studies.

Within-Season Distribution of External Training and Racing Workload in Professional Male Road Cyclists.

PubMed

Metcalfe, Alan J; Menaspà, Paolo; Villerius, Vincent; Quod, Marc; Peiffer, Jeremiah J; Govus, Andrew D; Abbiss, Chris R

2017-04-01

To describe the within-season external workloads of professional male road cyclists for optimal training prescription. Training and racing of 4 international competitive professional male cyclists (age 24 ± 2 y, body mass 77.6 ± 1.5 kg) were monitored for 12 mo before the world team-time-trial championships. Three within-season phases leading up to the team-time-trial world championships on September 20, 2015, were defined as phase 1 (Oct-Jan), phase 2 (Feb-May), and phase 3 (June-Sept). Distance and time were compared between training and racing days and over each of the various phases. Times spent in absolute (<100, 100-300, 400-500, >500 W) and relative (0-1.9, 2.0-4.9, 5.0-7.9, >8 W/kg) power zones were also compared for the whole season and between phases 1-3. Total distance (3859 ± 959 vs 10911 ± 620 km) and time (240.5 ± 37.5 vs 337.5 ± 26 h) were lower (P < .01) in phase 1 than phase 2. Total distance decreased (P < .01) from phase 2 to phase 3 (10911 ± 620 vs 8411 ± 1399 km, respectively). Mean absolute (236 ± 12.1 vs 197 ± 3 W) and relative (3.1 ± 0 vs 2.5 ± 0 W/kg) power output were higher (P < .05) during racing than training, respectively. Volume and intensity differed between training and racing over each of 3 distinct within-season phases.

The effect of path length and display size on memory for spatial information.

PubMed

Guérard, Katherine; Tremblay, Sébastien

2012-01-01

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

Differential computation method used to calibrate the angle-centroid relationship in coaxial reverse Hartmann test

NASA Astrophysics Data System (ADS)

Li, Xinji; Hui, Mei; Zhao, Zhu; Liu, Ming; Dong, Liquan; Kong, Lingqin; Zhao, Yuejin

2018-05-01

A differential computation method is presented to improve the precision of calibration for coaxial reverse Hartmann test (RHT). In the calibration, the accuracy of the distance measurement greatly influences the surface shape test, as demonstrated in the mathematical analyses. However, high-precision absolute distance measurement is difficult in the calibration. Thus, a differential computation method that only requires the relative distance was developed. In the proposed method, a liquid crystal display screen successively displayed two regular dot matrix patterns with different dot spacing. In a special case, images on the detector exhibited similar centroid distributions during the reflector translation. Thus, the critical value of the relative displacement distance and the centroid distributions of the dots on the detector were utilized to establish the relationship between the rays at certain angles and the detector coordinates. Experiments revealed the approximately linear behavior of the centroid variation with the relative displacement distance. With the differential computation method, we increased the precision of traditional calibration 10-5 rad root mean square. The precision of the RHT was increased by approximately 100 nm.

The luminosities of the coldest brown dwarfs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tinney, C. G.; Faherty, Jacqueline K.; Kirkpatrick, J. Davy

2014-11-20

In recent years, brown dwarfs have been extended to a new Y-dwarf class with effective temperatures colder than 500 K and masses in the range of 5-30 Jupiter masses. They fill a crucial gap in observable atmospheric properties between the much colder gas-giant planets of our own solar system (at around 130 K) and both hotter T-type brown dwarfs and the hotter planets that can be imaged orbiting young nearby stars (both with effective temperatures in the range of 1500-1000 K). Distance measurements for these objects deliver absolute magnitudes that make critical tests of our understanding of very cool atmospheres.more » Here we report new distances for nine Y dwarfs and seven very late T dwarfs. These reveal that Y dwarfs do indeed represent a continuation of the T-dwarf sequence to both fainter luminosities and cooler temperatures. They also show that the coolest objects display a large range in absolute magnitude for a given photometric color. The latest atmospheric models show good agreement with the majority of these Y-dwarf absolute magnitudes. This is also the case for WISE0855-0714, the coldest and closest brown dwarf to the Sun, which shows evidence for water ice clouds. However, there are also some outstanding exceptions, which suggest either binarity or the presence of condensate clouds. The former is readily testable with current adaptive optics facilities. The latter would mean that the range of cloudiness in Y dwarfs is substantial with most hosting almost no clouds—while others have dense clouds, making them prime targets for future variability observations to study cloud dynamics.« less

Autofocus algorithm for synthetic aperture radar imaging with large curvilinear apertures

NASA Astrophysics Data System (ADS)

Bleszynski, E.; Bleszynski, M.; Jaroszewicz, T.

2013-05-01

An approach to autofocusing for large curved synthetic aperture radar (SAR) apertures is presented. Its essential feature is that phase corrections are being extracted not directly from SAR images, but rather from reconstructed SAR phase-history data representing windowed patches of the scene, of sizes sufficiently small to allow the linearization of the forward- and back-projection formulae. The algorithm processes data associated with each patch independently and in two steps. The first step employs a phase-gradient-type method in which phase correction compensating (possibly rapid) trajectory perturbations are estimated from the reconstructed phase history for the dominant scattering point on the patch. The second step uses phase-gradient-corrected data and extracts the absolute phase value, removing in this way phase ambiguities and reducing possible imperfections of the first stage, and providing the distances between the sensor and the scattering point with accuracy comparable to the wavelength. The features of the proposed autofocusing method are illustrated in its applications to intentionally corrupted small-scene 2006 Gotcha data. The examples include the extraction of absolute phases (ranges) for selected prominent point targets. They are then used to focus the scene and determine relative target-target distances.

[Tracing Sources of Sulfate Aerosol in Nanjing Northern Suburb Using Sulfur and Oxygen Isotopes].

PubMed

Wei, Ying; Guo, Zhao-bing; Ge, Xin; Zhu, Sheng-nan; Jiang, Wen-juan; Shi, Lei; Chen, Shu

2015-04-01

Abstract: To trace the sources of sulfate contributing to atmospheric aerosol, PM2.5 samples for isotopic analysis were collected in Nanjing northern suburb during January 2014. The sulfur and oxygen isotopic compositions of sulfate from these samples were determined by EA-IRMS. Source identification and apportionment were carried out using stable isotopic and chemical evidences, combined with absolute principal component analysis (APCA) method. The Δ34S values of aerosol sulfate ranged from 2.7 per thousand to 6.4 per thousand, with an average of 5.0 per thousand ± 0.9 per thousand, while the Δ18O values ranged from 10.6 per thousand to 16.1 per thousand, with an average of 12.5 per thousand ± 1.37 per thousand. In conjunction with air mass trajectories, the results suggested that aerosol sulfates were controlled by a dominance of local anthropogenic sulfate, followed by the contributions of long-distance transported sulfate. There was a minor effect of some other low-Δ34S valued sulfates, which might be expected from biogenic sources. Absolute principal component analysis results showed that the contributions of anthropogenic sulfate and long-distance transported sulfate were 46.74% and 31.54%, respectively.

Gravity and the geoid in the Nepal Himalaya

NASA Technical Reports Server (NTRS)

Bilham, Roger

1992-01-01

Materials within the Himalaya are rising due to convergence between India and Asia. If the rate of erosion is comparable to the rate of uplift, the mean surface elevation will remain constant. Any slight imbalance in these two processes will lead to growth or attrition of the Himalaya. Although buried rocks, minerals and surface control points in the Himalaya are undoubtably rising, the growth or collapse or the Himalaya depends on the erosion rate which is invisible to geodetic measurements. A way to measure erosion rate is to measure the rate of change of gravity in a region of uplift. Essentially gravity should change precisely in accord with a change in elevation of the point in a free air gradient if erosion equals uplift rate. A measurement of absolute gravity was made simultaneously with measurements of GPS height within the Himalaya. Absolute gravity is estimated from the change in velocity per unit distance of a falling corner cube in a vacuum. Time is measured with an atomic clock and the unit distance corresponds to the wavelength of an iodine stabilized laser. An experiment undertaken in the Himalaya in 1991 provide a site description also with a instrument description.

Multiple-wavelength spectroscopic quantitation of light-absorbing species in scattering media

DOEpatents

Nathel, Howard; Cartland, Harry E.; Colston, Jr., Billy W.; Everett, Matthew J.; Roe, Jeffery N.

2000-01-01

An oxygen concentration measurement system for blood hemoglobin comprises a multiple-wavelength low-coherence optical light source that is coupled by single mode fibers through a splitter and combiner and focused on both a target tissue sample and a reference mirror. Reflections from both the reference mirror and from the depths of the target tissue sample are carried back and mixed to produce interference fringes in the splitter and combiner. The reference mirror is set such that the distance traversed in the reference path is the same as the distance traversed into and back from the target tissue sample at some depth in the sample that will provide light attenuation information that is dependent on the oxygen in blood hemoglobin in the target tissue sample. Two wavelengths of light are used to obtain concentrations. The method can be used to measure total hemoglobin concentration [Hb.sub.deoxy +Hb.sub.oxy ] or total blood volume in tissue and in conjunction with oxygen saturation measurements from pulse oximetry can be used to absolutely quantify oxyhemoglobin [HbO.sub.2 ] in tissue. The apparatus and method provide a general means for absolute quantitation of an absorber dispersed in a highly scattering medium.

Oxygen production rates for P/Halley over much of the 1985-1986 apparition

NASA Technical Reports Server (NTRS)

Spinrad, Hyron; Mccarthy, Patrick J.; Strauss, Michael A.

1986-01-01

Long slit CCD spectrophotometry of comet P/Halley in the visible region was used to measure the production rate of atomic oxygen during the 1985/86 apparition. The observations cover a large range of heliocentric distances, since the technique is applicable to apparently bright and faint comets. The cometary gas production rate for P/Halley increases rapidly with decreasing heliocentric distance toward perihelion and is systematicaly larger at a given heliocentric distance for the postperihelion observations. The average production rate for O1D on the day of the Giotto flyby is 4 times 10 to the 28th power atoms/sec giving an extrapolated total water production rate of 6 times 10 to the 29th power mols/sec. A method for comparing the absolute cometary gas production rates for different comets is discussed.

Direct measurement of interaction forces between a single bacterium and a flat plate.

PubMed

Klein, Jonah D; Clapp, Aaron R; Dickinson, Richard B

2003-05-15

A technique for precisely measuring the equilibrium and viscous interaction forces between a single bacterium and a flat surface as functions of separation distance is described. A single-beam gradient optical trap was used to micromanipulate the bacterium against a flat surface while evanescent wave light scattering was used to measure separation distances. Calibrating the optical trap far from the surface allowed the trapped bacterium to be used as a force probe. Equilibrium force-distance profiles were determined by measuring the deflection of the cell from the center of the optical trap at various trap positions. Simultaneously, viscous forces were determined by measuring the relaxation time for the fluctuating bacterium. Absolute distances were determined using a best-fit approximation to the theoretical prediction for the hindered mobility of a diffusing sphere near a wall. Using this approach, forces in the range from 0.01 to 4 pN were measured at near-nanometer resolution between Staphylococcus aureus and glass that was bare or coated with adsorbed protein.

H0, q0 and the local velocity field. [Hubble and deceleration constants in Big Bang expansion

NASA Technical Reports Server (NTRS)

Sandage, A.; Tammann, G. A.

1982-01-01

An attempt is made to find a systematic deviation from linearity for distances that are under the control of the Virgo cluster, and to determine the value of the mean random motion about the systematic flow, in order to improve the measurement of the Hubble and the deceleration constants. The velocity-distance relation for large and intermediate distances is studied, and type I supernovae are calibrated relatively as distance indicators and absolutely to obtain a new value for the Hubble constant. Methods of determining the deceleration constant are assessed, including determination from direct measurement, mean luminosity density, virgocentric motion, and the time scale test. The very local velocity field is investigated, and a solution is preferred with a random peculiar radial velocity of very nearby field galaxies of 90-100 km/s, and a Virgocentric motion of the local group of 220 km/s, leading to an underlying expansion rate of 55, in satisfactory agreement with the global value.

Can a one-layer optical skin model including melanin and inhomogeneously distributed blood explain spatially resolved diffuse reflectance spectra?

NASA Astrophysics Data System (ADS)

Karlsson, Hanna; Pettersson, Anders; Larsson, Marcus; Strömberg, Tomas

2011-02-01

Model based analysis of calibrated diffuse reflectance spectroscopy can be used for determining oxygenation and concentration of skin chromophores. This study aimed at assessing the effect of including melanin in addition to hemoglobin (Hb) as chromophores and compensating for inhomogeneously distributed blood (vessel packaging), in a single-layer skin model. Spectra from four humans were collected during different provocations using a twochannel fiber optic probe with source-detector separations 0.4 and 1.2 mm. Absolute calibrated spectra using data from either a single distance or both distances were analyzed using inverse Monte Carlo for light transport and Levenberg-Marquardt for non-linear fitting. The model fitting was excellent using a single distance. However, the estimated model failed to explain spectra from the other distance. The two-distance model did not fit the data well at either distance. Model fitting was significantly improved including melanin and vessel packaging. The most prominent effect when fitting data from the larger separation compared to the smaller separation was a different light scattering decay with wavelength, while the tissue fraction of Hb and saturation were similar. For modeling spectra at both distances, we propose using either a multi-layer skin model or a more advanced model for the scattering phase function.

Local Inhibition of HSP90 to Prevent Intimal Hyperplasia after Balloon Injury

DTIC Science & Technology

2017-10-01

Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Peripheral arterial disease (PAD) remains a major threat to life and limb and represents a disabling and...Organizations…………… 5 1 1. INTRODUCTION: Peripheral arterial disease (PAD) is a significant health problem that affects the aging military and veteran...population, ranging from lifestyle limiting claudication to major amputation and death. Further, there is growing rate of disorders in Cardiovascular Health

Involvement of Ultramarathon Runners: Understanding Intention, Behavior, and Perceived Skill of the "Absolute Unitary Being"

ERIC Educational Resources Information Center

Mueller, Thomas S.

2012-01-01

Ultramarathon running, competing in distances beyond the 26.2 mile marathon, is one of the fastest growing segments of endurance competition. The sport has more than tripled in entrant size over the past 12 years and now attracts over 26,000 athletes on an annual basis. However, there is a limited understanding of what motivates individuals to…

Relationship between traditional and ballistic squat exercise with vertical jumping and maximal sprinting.

PubMed

Requena, Bernardo; García, Inmaculada; Requena, Francisco; de Villarreal, Eduardo Sáez-Sáez; Cronin, John B

2011-08-01

The purpose of this study was to quantify the magnitude of the relationship between vertical jumping and maximal sprinting at different distances with performance in the traditional and ballistic concentric squat exercise in well-trained sprinters. Twenty-one men performed 2 types of barbell squats (ballistic and traditional) across different loads with the aim of determining the maximal peak and average power outputs and 1 repetition maximum (1RM) values. Moreover, vertical jumping (countermovement jump test [CMJ]) and maximal sprints over 10, 20, 30, 40, 60, and 80 m were also assessed. In respect to 1RM in traditional squat, (a) no significant correlation was found with CMJ performance; (b) positive strong relationships (p < 0.01) were obtained with all the power measures obtained during both ballistic and traditional squat exercises (r = 0.53-0.90); (c) negative significant correlations (r = -0.49 to -0.59, p < 0.05) were found with sprint times in all the sprint distances measured when squat strength was expressed as a relative value; however, in the absolute mode, no significant relationships were observed with 10- and 20-m sprint times. No significant relationship was found between 10-m sprint time and relative or absolute power outputs using either ballistic or traditional squat exercises. Sprint time at 20 m was only related to ballistic and traditional squat performance when power values were expressed in relative terms. Moderate significant correlations (r = -0.39 to -0.56, p < 0.05) were observed between sprint times at 30 and 40 m and the absolute/relative power measures attained in both ballistic and traditional squat exercises. Sprint times at 60 and 80 m were mainly related to ballistic squat power outputs. Although correlations can only give insights into associations and not into cause and effect, from this investigation, it can be seen that traditional squat strength has little in common with CMJ performance and that relative 1RM and power outputs for both squat exercises are statistically correlated to most sprint distances underlying the importance of strength and power to sprinting.

Hybrid Endovascular Aortic Aneurysm Repair: Preservation of Pelvic Perfusion with External to Internal Iliac Artery Bypass.

PubMed

Mansukhani, Neel A; Havelka, George E; Helenowski, Irene B; Rodriguez, Heron E; Hoel, Andrew W; Eskandari, Mark K

2017-07-01

Diminished pelvic arterial flow as a result of intentional coverage/embolization of internal iliac arteries (IIA) during isolated endovascular common iliac artery aneurysm (CIAA) repair or endovascular repair of abdominal aortic aneurysms (EVAR) may result in symptomatic pelvic ischemia. Although generally well tolerated, in severe cases, pelvic ischemia may manifest as recalcitrant buttock claudication, vasculogenic impotence, or perineal, vesicle, rectal, and/or spinal cord ischemia. Branched graft technology has recently become available; however, many patients are not candidates for endovascular repair with these devices. Therefore, techniques to preserve pelvic arterial flow are needed. We reviewed our outcomes of isolated endovascular CIAA repair or EVAR in conjunction with unilateral external-internal iliac artery bypass. Single-center, retrospective review of 10 consecutive patients who underwent hybrid endovascular abdominal aortic aneurysm (AAA) or CIAA repair with concomitant external-internal iliac artery bypass between 2006 and 2015. Demographics, index procedural details, postoperative symptoms, hospital length of stay (LOS), follow-up imaging, and bypass patency were recorded. The cohort of 10 patients was all men with a mean age of 71 years (range: 56-84). Hybrid repair consisted of contralateral IIA coil embolization followed by EVAR with external iliac artery-internal iliac artery (EIA-IIA) bypass. All EIA-IIA bypasses were performed via a standard lower quadrant retroperitoneal approach with a prosthetic bypass graft. Technical success was 100%, and there were no perioperative deaths. One patient developed transient paraplegia, 1 patient had buttock claudication on the side of his hypogastric embolization contralateral to his iliac bypass, and 1 developed postoperative impotence. 20% of patients sustained long-term complications (buttock claudication and postoperative impotence). Mean LOS was 2.8 days (range: 1-9 days). Postoperative imaging was obtained in 90% of patients, and mean follow-up was 10.8 months (range: 0.5-36 months). All bypasses remained patent. Although branched graft technology continues to evolve, strategies to maintain adequate pelvic circulation are necessary to avoid the devastating complications of pelvic ischemia. We have demonstrated that a hybrid approach combining EVAR or isolated endovascular common iliac artery exclusion with a unilateral external-internal iliac bypass via a retroperitoneal approach is well tolerated with a short LOS and excellent patency rates. Copyright © 2017 Elsevier Inc. All rights reserved.

Validation of the Edinburgh Claudication Questionnaire in 1st generation Black African-Caribbean and South Asian UK migrants: a sub-study to the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study.

PubMed

Bennett, Philip C; Lip, Gregory Y H; Silverman, Stanley; Blann, Andrew D; Gill, Paramjit S

2011-06-03

We determined the diagnostic accuracy of the Edinburgh Claudication Questionnaire (ECQ) in 1st generation Black African-Caribbean UK migrants as previous diagnostic questionnaires have been found to be less accurate in this population. We also determined the diagnostic accuracy of translated versions of the ECQ in 1st generation South Asian UK migrants, as this has not been investigated before. Subjects were recruited from the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study, a community based screening survey for heart failure in minority ethnic groups. Translated versions of the ECQ were prepared following a recognised protocol. All participants attending screening between October 2007 and February 2009 were asked to complete the ECQ in the language of their choice (English, Punjabi, Bengali, Urdu, Hindi or Gujarati). Subjects answering positively to experiencing leg pain or discomfort on walking were asked to return to have Ankle Brachial Pressure Index (ABPI) measured. 154 out of 2831 subjects participating in E-ECHOES (5.4%) were eligible to participate in this sub-study, for which 74.3% returned for ABPI assessment. Non-responders were younger than participants (59[9] vs. 65[11] years; p=0.015). Punjabi, English and Bengali questionnaires identified participants with Intermittent Claudication, so these questionnaires were assessed. The sensitivities (SN), specificities (SP), positive (PPV) and negative (NPV) predictive values were calculated. English: SN: 50%; SP: 68%; PPV: 43%; NPV: 74%. Punjabi: SN: 50%; SP: 87%; PPV: 43%; NPV: 90%. Bengali: SN: 33%; SP: 50%; PPV: 13%; NPV: 73%. There were significant differences in diagnostic accuracy between the 3 versions (Punjabi: 83.8%; Bengali: 45%; English: 62.2%; p<0.0001). No significant differences were found in sensitivity and specificity between illiterate and literate participants in any of the questionnaires and there was no significant different difference between those under and over 60 years of age. Our findings suggest that the ECQ is not as sensitive or specific a diagnostic tool in 1st generation Black African-Caribbean and South Asian UK migrants than in the Edinburgh Artery Study, reflecting the findings of other diagnostic questionnaires in these minority ethnic groups. However this study is limited by sample size so conclusions should be interpreted with caution.

Performance Evaluation of sUAS Equipped with Velodyne HDL-32E LiDAR Sensor

NASA Astrophysics Data System (ADS)

Jozkow, G.; Wieczorek, P.; Karpina, M.; Walicka, A.; Borkowski, A.

2017-08-01

The Velodyne HDL-32E laser scanner is used more frequently as main mapping sensor in small commercial UASs. However, there is still little information about the actual accuracy of point clouds collected with such UASs. This work evaluates empirically the accuracy of the point cloud collected with such UAS. Accuracy assessment was conducted in four aspects: impact of sensors on theoretical point cloud accuracy, trajectory reconstruction quality, and internal and absolute point cloud accuracies. Theoretical point cloud accuracy was evaluated by calculating 3D position error knowing errors of used sensors. The quality of trajectory reconstruction was assessed by comparing position and attitude differences from forward and reverse EKF solution. Internal and absolute accuracies were evaluated by fitting planes to 8 point cloud samples extracted for planar surfaces. In addition, the absolute accuracy was also determined by calculating point 3D distances between LiDAR UAS and reference TLS point clouds. Test data consisted of point clouds collected in two separate flights performed over the same area. Executed experiments showed that in tested UAS, the trajectory reconstruction, especially attitude, has significant impact on point cloud accuracy. Estimated absolute accuracy of point clouds collected during both test flights was better than 10 cm, thus investigated UAS fits mapping-grade category.

Microplastic deformation of polycrystalline iron and molybdenum subjected to high-current electron-beam irradiation

NASA Astrophysics Data System (ADS)

Dudarev, E. F.; Pochivalova, G. P.; Proskurovskii, D. I.; Rotshtein, V. P.; Markov, A. B.

1996-03-01

A technique for determination of residual stresses at various distances from the irradiated surface is proposed. It is established for iron and molybdenum that compressive stresses are set up under irradiation by low-energy high-current electron beams and that their values decrease sharply with increasing distance from the surface. The residual stresses are much smaller in absolute magnitude than those operating during irradiation. It is shown that the change in resistance to microplastic deformation on irradiation with low-energy high-current electron beams is governed not only by formation of a gradient dislocation substructure in the surface layer, but also by the residual stresses and the appearance of the Bauschinger effect.

Resolution-enhancement and sampling error correction based on molecular absorption line in frequency scanning interferometry

NASA Astrophysics Data System (ADS)

Pan, Hao; Qu, Xinghua; Shi, Chunzhao; Zhang, Fumin; Li, Yating

2018-06-01

The non-uniform interval resampling method has been widely used in frequency modulated continuous wave (FMCW) laser ranging. In the large-bandwidth and long-distance measurements, the range peak is deteriorated due to the fiber dispersion mismatch. In this study, we analyze the frequency-sampling error caused by the mismatch and measure it using the spectroscopy of molecular frequency references line. By using the adjacent points' replacement and spline interpolation technique, the sampling errors could be eliminated. The results demonstrated that proposed method is suitable for resolution-enhancement and high-precision measurement. Moreover, using the proposed method, we achieved the precision of absolute distance less than 45 μm within 8 m.

Long-distance quantum communication with atomic ensembles and linear optics.

PubMed

Duan, L M; Lukin, M D; Cirac, J I; Zoller, P

2001-11-22

Quantum communication holds promise for absolutely secure transmission of secret messages and the faithful transfer of unknown quantum states. Photonic channels appear to be very attractive for the physical implementation of quantum communication. However, owing to losses and decoherence in the channel, the communication fidelity decreases exponentially with the channel length. Here we describe a scheme that allows the implementation of robust quantum communication over long lossy channels. The scheme involves laser manipulation of atomic ensembles, beam splitters, and single-photon detectors with moderate efficiencies, and is therefore compatible with current experimental technology. We show that the communication efficiency scales polynomially with the channel length, and hence the scheme should be operable over very long distances.

High resolution kilometric range optical telemetry in air by radio frequency phase measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guillory, Joffray; García-Márquez, Jorge; Truong, Daniel

2016-07-15

We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances upmore » to 1.2 km.« less

The JILA (Joint Institute for Laboratory Astrophysics) portable absolute gravity apparatus

NASA Astrophysics Data System (ADS)

Faller, J. E.; Guo, Y. G.; Gschwind, J.; Niebauer, T. M.; Rinker, R. L.; Xue, J.

1983-08-01

We have developed a new and highly portable absolute gravity apparatus based on the principles of free-fall laser interferometry. A primary concern over the past several years has been the detection, understanding, and elimination of systematic errors. In the Spring of 1982, we used this instrument to carry out a survey at twelve sites in the United States. Over a period of eight weeks, the instrument was driven a distance of nearly 20,000 km to sites in California, New Mexico, Colorado, Wyoming, Maryland, and Massachusetts. The time required to carry out a measurement at each location was typically one day. Over the next several years, our intention is to see absolute gravity measurements become both usable and used in the field. To this end, and in the context of cooperative research programs with a number of scientific institutes throughout the world, we are building additional instruments (incorporating further refinements) which are to be used for geodetic, geophysical, geological, and tectonic studies. With these new instruments we expect to improve (perhaps by a factor of two) on the 6-10 microgal accuracy of our present instrument. Today, one can make absolutely gravity measurements as accurately as - possibly even more accurately than - one can make relative measurements. Given reasonable success with the new instruments in the field, the last years of this century should see absolute gravity measurement mature both as a new geodetic data type and as a useful geophysical tool.

Hierarchical traits distances explain grassland Fabaceae species' ecological niches distances.

PubMed

Fort, Florian; Jouany, Claire; Cruz, Pablo

2015-01-01

Fabaceae species play a key role in ecosystem functioning through their capacity to fix atmospheric nitrogen via their symbiosis with Rhizobium bacteria. To increase benefits of using Fabaceae in agricultural systems, it is necessary to find ways to evaluate species or genotypes having potential adaptations to sub-optimal growth conditions. We evaluated the relevance of phylogenetic distance, absolute trait distance and hierarchical trait distance for comparing the adaptation of 13 grassland Fabaceae species to different habitats, i.e., ecological niches. We measured a wide range of functional traits (root traits, leaf traits, and whole plant traits) in these species. Species phylogenetic and ecological distances were assessed from a species-level phylogenetic tree and species' ecological indicator values, respectively. We demonstrated that differences in ecological niches between grassland Fabaceae species were related more to their hierarchical trait distances than to their phylogenetic distances. We showed that grassland Fabaceae functional traits tend to converge among species with the same ecological requirements. Species with acquisitive root strategies (thin roots, shallow root systems) are competitive species adapted to non-stressful meadows, while conservative ones (coarse roots, deep root systems) are able to tolerate stressful continental climates. In contrast, acquisitive species appeared to be able to tolerate low soil-P availability, while conservative ones need high P availability. Finally we highlight that traits converge along the ecological gradient, providing the assumption that species with similar root-trait values are better able to coexist, regardless of their phylogenetic distance.

Hierarchical traits distances explain grassland Fabaceae species' ecological niches distances

PubMed Central

Fort, Florian; Jouany, Claire; Cruz, Pablo

2015-01-01

Fabaceae species play a key role in ecosystem functioning through their capacity to fix atmospheric nitrogen via their symbiosis with Rhizobium bacteria. To increase benefits of using Fabaceae in agricultural systems, it is necessary to find ways to evaluate species or genotypes having potential adaptations to sub-optimal growth conditions. We evaluated the relevance of phylogenetic distance, absolute trait distance and hierarchical trait distance for comparing the adaptation of 13 grassland Fabaceae species to different habitats, i.e., ecological niches. We measured a wide range of functional traits (root traits, leaf traits, and whole plant traits) in these species. Species phylogenetic and ecological distances were assessed from a species-level phylogenetic tree and species' ecological indicator values, respectively. We demonstrated that differences in ecological niches between grassland Fabaceae species were related more to their hierarchical trait distances than to their phylogenetic distances. We showed that grassland Fabaceae functional traits tend to converge among species with the same ecological requirements. Species with acquisitive root strategies (thin roots, shallow root systems) are competitive species adapted to non-stressful meadows, while conservative ones (coarse roots, deep root systems) are able to tolerate stressful continental climates. In contrast, acquisitive species appeared to be able to tolerate low soil-P availability, while conservative ones need high P availability. Finally we highlight that traits converge along the ecological gradient, providing the assumption that species with similar root-trait values are better able to coexist, regardless of their phylogenetic distance. PMID:25741353

Hydrodynamic chromatography of polystyrene microparticles in micropillar array columns.

PubMed

Op de Beeck, Jeff; De Malsche, Wim; Vangelooven, Joris; Gardeniers, Han; Desmet, Gert

2010-09-24

We report on the possibility to perform HDC in micropillar array columns and the potential advantages of such a system. The HDC performance of a pillar array column with pillar diameter = 5 microm and an interpillar distance of 2.5 microm has been characterized using both a low MW tracer (FITC) and differently sized polystyrene bead samples (100, 200 and 500 nm). The reduced plate height curves that were obtained for the different investigated markers all overlapped very well, and attained a minimum value of about h(min)=0.3 (reduction based on the pillar diameter), corresponding to 1.6 microm in absolute value and giving good prospects for high efficiency separations. The obtained reduced retention time values were in fair agreement with that predicted by the Di Marzio and Guttman model for a flow between flat plates, using the minimal interpillar distance as characteristic interplate distance. Copyright 2010 Elsevier B.V. All rights reserved.

SMOQ: a tool for predicting the absolute residue-specific quality of a single protein model with support vector machines

PubMed Central

2014-01-01

Background It is important to predict the quality of a protein structural model before its native structure is known. The method that can predict the absolute local quality of individual residues in a single protein model is rare, yet particularly needed for using, ranking and refining protein models. Results We developed a machine learning tool (SMOQ) that can predict the distance deviation of each residue in a single protein model. SMOQ uses support vector machines (SVM) with protein sequence and structural features (i.e. basic feature set), including amino acid sequence, secondary structures, solvent accessibilities, and residue-residue contacts to make predictions. We also trained a SVM model with two new additional features (profiles and SOV scores) on 20 CASP8 targets and found that including them can only improve the performance when real deviations between native and model are higher than 5Å. The SMOQ tool finally released uses the basic feature set trained on 85 CASP8 targets. Moreover, SMOQ implemented a way to convert predicted local quality scores into a global quality score. SMOQ was tested on the 84 CASP9 single-domain targets. The average difference between the residue-specific distance deviation predicted by our method and the actual distance deviation on the test data is 2.637Å. The global quality prediction accuracy of the tool is comparable to other good tools on the same benchmark. Conclusion SMOQ is a useful tool for protein single model quality assessment. Its source code and executable are available at: http://sysbio.rnet.missouri.edu/multicom_toolbox/. PMID:24776231

SMOQ: a tool for predicting the absolute residue-specific quality of a single protein model with support vector machines.

PubMed

Cao, Renzhi; Wang, Zheng; Wang, Yiheng; Cheng, Jianlin

2014-04-28

It is important to predict the quality of a protein structural model before its native structure is known. The method that can predict the absolute local quality of individual residues in a single protein model is rare, yet particularly needed for using, ranking and refining protein models. We developed a machine learning tool (SMOQ) that can predict the distance deviation of each residue in a single protein model. SMOQ uses support vector machines (SVM) with protein sequence and structural features (i.e. basic feature set), including amino acid sequence, secondary structures, solvent accessibilities, and residue-residue contacts to make predictions. We also trained a SVM model with two new additional features (profiles and SOV scores) on 20 CASP8 targets and found that including them can only improve the performance when real deviations between native and model are higher than 5Å. The SMOQ tool finally released uses the basic feature set trained on 85 CASP8 targets. Moreover, SMOQ implemented a way to convert predicted local quality scores into a global quality score. SMOQ was tested on the 84 CASP9 single-domain targets. The average difference between the residue-specific distance deviation predicted by our method and the actual distance deviation on the test data is 2.637Å. The global quality prediction accuracy of the tool is comparable to other good tools on the same benchmark. SMOQ is a useful tool for protein single model quality assessment. Its source code and executable are available at: http://sysbio.rnet.missouri.edu/multicom_toolbox/.

Effect of reconstructive vascular surgery on red cell deformability--preliminary results.

PubMed Central

Irwin, S T; Rocks, M J; McGuigan, J A; Patterson, C C; Morris, T C; O'Reilly, M J

1983-01-01

Using a simple filtration method, red cell deformability was measured in healthy control subjects and in patients with peripheral vascular disease. Impaired red cell deformability was demonstrated in patients with rest pain or gangrene and in patients with intermittent claudication. An improvement in red cell deformability was demonstrated after successful reconstructive vascular surgery in both patient groups. An improvement in red cell deformability was demonstrated in patients undergoing major limb amputation. PMID:6619311

The role of sacroiliac joint dysfunction in the genesis of low back pain: the obvious is not always right.

PubMed

Weksler, Natan; Velan, Gad J; Semionov, Michael; Gurevitch, Boris; Klein, Moti; Rozentsveig, Vsevolod; Rudich, Tzvia

2007-12-01

It is a common practice to the link low back pain with protruding disc even when neurological signs are absent. Because pain caused by sacroiliac joint dysfunction can mimic discogenic or radicular low back pain, we assumed that the diagnosis of sacroiliac joint dysfunction is frequently overlooked. To assess the incidence of sacroiliac joint dysfunction in patients with low back pain and positive disc findings on CT scan or MRI, but without claudication or objective neurological deficits. Fifty patients with low back pain and disc herniation, without claudication or neurological abnormalities such as decreased motor strength, sensory alterations or sphincter incontinence and with positive pain provocation tests for sacroiliac joint dysfunction were submitted to fluoroscopic diagnostic sacroiliac joint infiltration. The mean baseline VAS pain score was 7.8 +/- 1.77 (range 5-10). Thirty minutes after infiltration, the mean VAS score was 1.3 +/- 1.76 (median 0.000E+00 with an average deviation from median = 1.30) (P = 0.0002). Forty-six patients had a VAS score ranging from 0 to 3, 8 weeks after the fluoroscopic guided infiltration. There were no serious complications after treatment. An unanticipated motor block that required hospitalization was seen in four patients, lasting from 12 to 36 h. Sacroiliac joint dysfunction should be considered strongly in the differential diagnosis of low back pain in this group of patients.

Effects of walking with a shopping trolley on spinal posture and loading in subjects with neurogenic claudication.

PubMed

Comer, Christine M; White, Derrick; Conaghan, Philip G; Bird, Howard A; Redmond, Anthony C

2010-10-01

To explore possible mechanisms underpinning symptom relief and improved walking tolerance in patients with neurogenic claudication (NC) when pushing a shopping trolley by evaluating the effects of a shopping trolley on spinal posture and loading patterns. An exploratory study of kinematic and kinetic changes in walking with and without pushing a shopping trolley in persons with NC symptoms and a comparison with asymptomatic control subjects. A primary care-based musculoskeletal service. Participants (n=8) with NC symptoms who have anecdotally reported symptomatic improvement when walking with a shopping trolley and a control group of asymptomatic persons (n=8). Shopping trolley. Changes in lumbar spinal sagittal posture and ground reaction force. Subjects with NC and asymptomatic controls walked with significantly more flexed spinal posture (increase in flexion, 3.40°; z=3.516; P<.001) and reduced mean ground reaction forces (-6.9% of body weight; z=-3.46; P=.001) when walking with a shopping trolley. However, at the midstance point of the gait cycle, controls showed minimal reliance on the trolley, whereas, people with NC showed continued offloading. Both posture and loading are affected by pushing a shopping trolley; however, patients with NC were found to offload the spine throughout the stance phase of gait, whereas asymptomatic controls did not. Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Influence of regular exercise on body fat and eating patterns of patients with intermittent claudication.

PubMed

Leicht, Anthony; Crowther, Robert; Golledge, Jonathan

2015-05-18

This study examined the impact of regular supervised exercise on body fat, assessed via anthropometry, and eating patterns of peripheral arterial disease patients with intermittent claudication (IC). Body fat, eating patterns and walking ability were assessed in 11 healthy adults (Control) and age- and mass-matched IC patients undertaking usual care (n = 10; IC-Con) or supervised exercise (12-months; n = 10; IC-Ex). At entry, all groups exhibited similar body fat and eating patterns. Maximal walking ability was greatest for Control participants and similar for IC-Ex and IC-Con patients. Supervised exercise resulted in significantly greater improvements in maximal walking ability (IC-Ex 148%-170% vs. IC-Con 29%-52%) and smaller increases in body fat (IC-Ex -2.1%-1.4% vs. IC-Con 8.4%-10%). IC-Con patients exhibited significantly greater increases in body fat compared with Control at follow-up (8.4%-10% vs. -0.6%-1.4%). Eating patterns were similar for all groups at follow-up. The current study demonstrated that regular, supervised exercise significantly improved maximal walking ability and minimised increase in body fat amongst IC patients without changes in eating patterns. The study supports the use of supervised exercise to minimize cardiovascular risk amongst IC patients. Further studies are needed to examine the additional value of other lifestyle interventions such as diet modification.

Clinical utility of colour flow Doppler ultrasonography in planning anterolateral thigh flap harvest.

PubMed

Patel, Rajan S; Higgins, Kevin M; Enepekides, Danny J; Hamilton, Paul A

2010-10-01

The anatomic variability of cutaneous perforators contributes to the technical challenges of anterolateral thigh (ALT) free flap harvest. The objective of this study was to assess the accuracy and clinical utility of preoperative colour flow Doppler (CFD) ultrasonography in evaluating planned ALT flap donor sites. A prospective study of the infrainguinal vasculature (profunda femoris and lateral circumflex femoral arteries) in 16 consecutive patients scheduled for ALT free flap transfer for reconstruction of head and neck surgical defects was undertaken. All patients underwent CFD ultrasonography. The location of perforators and the thigh thickness determined by CFD ultrasonography were correlated with the actual intraoperative findings using a scatter plot and paired t-test. Two patients were diagnosed with bilateral silent infrainguinal claudication, which precluded safe use of the ALT donor site. In two other patients, the planned ALT donor site ipsilateral to the defect was not used because of silent infrainguinal claudication diagnosed by CFD ultrasonography. In the 14 patients who underwent ALT flap harvest, CFD ultrasonography identified 48 perforators, which coincided with 43 actual perforators found intraoperatively. CFD ultrasonography demonstrated a statistically significant correlation with the actual perforator locations (Spearman coefficient .76; p = .55). Although CFD ultrasonography tended to underestimate flap thickness, there was a statistically significant correlation (Spearman coefficient .94; p ≤ .0001) with the actual flap thickness. CFD ultrasonography has clinical utility in facilitating decision making and planning ALT flap harvest.

Swept Frequency Laser Metrology System

NASA Technical Reports Server (NTRS)

Zhao, Feng (Inventor)

2010-01-01

A swept frequency laser ranging system having sub-micron accuracy that employs multiple common-path heterodyne interferometers, one coupled to a calibrated delay-line for use as an absolute reference for the ranging system. An exemplary embodiment uses two laser heterodyne interferometers to create two laser beams at two different frequencies to measure distance and motions of target(s). Heterodyne fringes generated from reflections off a reference fiducial X(sub R) and measurement (or target) fiducial X(sub M) are reflected back and are then detected by photodiodes. The measured phase changes Delta phi(sub R) and Delta phi (sub m) resulting from the laser frequency swept gives target position. The reference delay-line is the only absolute reference needed in the metrology system and this provides an ultra-stable reference and simple/economical system.

Using an interference spectrum as a short-range absolute rangefinder with fiber and wideband source

NASA Astrophysics Data System (ADS)

Hsieh, Tsung-Han; Han, Pin

2018-06-01

Recently, a new type of displacement instrument using spectral-interference has been found, which utilizes fiber and a wideband light source to produce an interference spectrum. In this work, we develop a method that measures the absolute air-gap distance by taking wavelengths at two interference spectra minima. The experimental results agree with the theoretical calculations. It is also utilized to produce and control the spectral switch, which is much easier than other previous methods using other control mechanisms. A scanning mode of this scheme for stepped surface measurement is suggested, which is verified by a standard thickness gauge test. Our scheme is different to one available on the market that may use a curve-fitting method, and some comparisons are made between our scheme and that one.

Orbital Solutions and Absolute Elements of the Eclipsing Binary YY Ceti

NASA Astrophysics Data System (ADS)

Williamon, Richard M.; Sowell, James R.

2012-05-01

YY Cet is a 10.5 mag semidetached variable with a 19 hr orbital period. The Wilson-Devinney program is used to simultaneously solve two new sets of UBV light curves together with preexisting photometry and single-line radial velocity measurements . The system has the lower-mass component completely filling its Roche lobe. The resulting masses are M1 = 1.78 ± 0.19 M⊙ and M2 = 0.92 ± 0.10 M⊙, and the radii are R1 = 2.08 ± 0.08 R⊙ and R2 = 1.62 ± 0.06 R⊙. Its computed distance is 534 ± 28 pc. Light- and velocity-curve parameters, orbital elements, and absolute dimensions are presented. A study of published TOM observations indicates that the period changed around 1999.

Distance and Kinematics of the Red Hypergiant VY CMa: Very Long Baseline Array and Very Large Array Astrometry

NASA Astrophysics Data System (ADS)

Zhang, B.; Reid, M. J.; Menten, K. M.; Zheng, X. W.

2012-01-01

We report astrometric results of phase-referencing very long baseline interferometry observations of 43 GHz SiO maser emission toward the red hypergiant VY Canis Majoris (VY CMa) using the Very Long Baseline Array (VLBA). We measured a trigonometric parallax of 0.83 ± 0.08 mas, corresponding to a distance of 1.20+0.13 -0.10 kpc. Compared to previous studies, the spatial distribution of SiO masers has changed dramatically, while its total extent remains similar. The internal motions of the maser spots are up to 1.4 mas yr-1, corresponding to 8 km s-1, and show a tendency for expansion. After modeling the expansion of maser spots, we derived an absolute proper motion for the central star of μ x = -2.8 ± 0.2 and μ y = 2.6 ± 0.2 mas yr-1 eastward and northward, respectively. Based on the maser distribution from the VLBA observations, and the relative position between the radio photosphere and the SiO maser emission at 43 GHz from the complementary Very Large Array observations, we estimate the absolute position of VY CMa at mean epoch 2006.53 to be αJ2000 = 07h22m58.s3259 ± 0.s0007, δJ2000 = -25°46'03farcs063 ± 0farcs010. The position and proper motion of VY CMa from the VLBA observations differ significantly with values measured by the Hipparcos satellite. These discrepancies are most likely associated with inhomogeneities and dust scattering the optical light in the circumstellar envelope. The absolute proper motion measured with VLBA suggests that VY CMa may be drifting out of the giant molecular cloud to the east of it.

Systematic error of the Gaia DR1 TGAS parallaxes from data for the red giant clump

NASA Astrophysics Data System (ADS)

Gontcharov, G. A.

2017-08-01

Based on the Gaia DR1 TGAS parallaxes and photometry from the Tycho-2, Gaia, 2MASS, andWISE catalogues, we have produced a sample of 100 000 clump red giants within 800 pc of the Sun. The systematic variations of the mode of their absolute magnitude as a function of the distance, magnitude, and other parameters have been analyzed. We show that these variations reach 0.7 mag and cannot be explained by variations in the interstellar extinction or intrinsic properties of stars and by selection. The only explanation seems to be a systematic error of the Gaia DR1 TGAS parallax dependent on the square of the observed distance in kpc: 0.18 R 2 mas. Allowance for this error reduces significantly the systematic dependences of the absolute magnitude mode on all parameters. This error reaches 0.1 mas within 800 pc of the Sun and allows an upper limit for the accuracy of the TGAS parallaxes to be estimated as 0.2 mas. A careful allowance for such errors is needed to use clump red giants as "standard candles." This eliminates all discrepancies between the theoretical and empirical estimates of the characteristics of these stars and allows us to obtain the first estimates of the modes of their absolute magnitudes from the Gaia parallaxes: mode( M H ) = -1.49 m ± 0.04 m , mode( M Ks ) = -1.63 m ± 0.03 m , mode( M W1) = -1.67 m ± 0.05 m mode( M W2) = -1.67 m ± 0.05 m , mode( M W3) = -1.66 m ± 0.02 m , mode( M W4) = -1.73 m ± 0.03 m , as well as the corresponding estimates of their de-reddened colors.

Estimation of distances to stars with stellar parameters from LAMOST

DOE PAGES

Carlin, Jeffrey L.; Liu, Chao; Newberg, Heidi Jo; ...

2015-06-05

Here, we present a method to estimate distances to stars with spectroscopically derived stellar parameters. The technique is a Bayesian approach with likelihood estimated via comparison of measured parameters to a grid of stellar isochrones, and returns a posterior probability density function for each star's absolute magnitude. We tailor this technique specifically to data from the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) survey. Because LAMOST obtains roughly 3000 stellar spectra simultaneously within each ~5-degree diameter "plate" that is observed, we can use the stellar parameters of the observed stars to account for the stellar luminosity function and targetmore » selection effects. This removes biasing assumptions about the underlying populations, both due to predictions of the luminosity function from stellar evolution modeling, and from Galactic models of stellar populations along each line of sight. Using calibration data of stars with known distances and stellar parameters, we show that our method recovers distances for most stars within ~20%, but with some systematic overestimation of distances to halo giants. We apply our code to the LAMOST database, and show that the current precision of LAMOST stellar parameters permits measurements of distances with ~40% error bars. This precision should improve as the LAMOST data pipelines continue to be refined.« less

Estimation of distances to stars with stellar parameters from LAMOST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlin, Jeffrey L.; Liu, Chao; Newberg, Heidi Jo

Here, we present a method to estimate distances to stars with spectroscopically derived stellar parameters. The technique is a Bayesian approach with likelihood estimated via comparison of measured parameters to a grid of stellar isochrones, and returns a posterior probability density function for each star's absolute magnitude. We tailor this technique specifically to data from the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) survey. Because LAMOST obtains roughly 3000 stellar spectra simultaneously within each ~5-degree diameter "plate" that is observed, we can use the stellar parameters of the observed stars to account for the stellar luminosity function and targetmore » selection effects. This removes biasing assumptions about the underlying populations, both due to predictions of the luminosity function from stellar evolution modeling, and from Galactic models of stellar populations along each line of sight. Using calibration data of stars with known distances and stellar parameters, we show that our method recovers distances for most stars within ~20%, but with some systematic overestimation of distances to halo giants. We apply our code to the LAMOST database, and show that the current precision of LAMOST stellar parameters permits measurements of distances with ~40% error bars. This precision should improve as the LAMOST data pipelines continue to be refined.« less

Accurate relative location estimates for the North Korean nuclear tests using empirical slowness corrections

NASA Astrophysics Data System (ADS)

Gibbons, S. J.; Pabian, F.; Näsholm, S. P.; Kværna, T.; Mykkeltveit, S.

2017-01-01

Declared North Korean nuclear tests in 2006, 2009, 2013 and 2016 were observed seismically at regional and teleseismic distances. Waveform similarity allows the events to be located relatively with far greater accuracy than the absolute locations can be determined from seismic data alone. There is now significant redundancy in the data given the large number of regional and teleseismic stations that have recorded multiple events, and relative location estimates can be confirmed independently by performing calculations on many mutually exclusive sets of measurements. Using a 1-D global velocity model, the distances between the events estimated using teleseismic P phases are found to be approximately 25 per cent shorter than the distances between events estimated using regional Pn phases. The 2009, 2013 and 2016 events all take place within 1 km of each other and the discrepancy between the regional and teleseismic relative location estimates is no more than about 150 m. The discrepancy is much more significant when estimating the location of the more distant 2006 event relative to the later explosions with regional and teleseismic estimates varying by many hundreds of metres. The relative location of the 2006 event is challenging given the smaller number of observing stations, the lower signal-to-noise ratio and significant waveform dissimilarity at some regional stations. The 2006 event is however highly significant in constraining the absolute locations in the terrain at the Punggye-ri test-site in relation to observed surface infrastructure. For each seismic arrival used to estimate the relative locations, we define a slowness scaling factor which multiplies the gradient of seismic traveltime versus distance, evaluated at the source, relative to the applied 1-D velocity model. A procedure for estimating correction terms which reduce the double-difference time residual vector norms is presented together with a discussion of the associated uncertainty. The modified velocity gradients reduce the residuals, the relative location uncertainties and the sensitivity to the combination of stations used. The traveltime gradients appear to be overestimated for the regional phases, and teleseismic relative location estimates are likely to be more accurate despite an apparent lower precision. Calibrations for regional phases are essential given that smaller magnitude events are likely not to be recorded teleseismically. We discuss the implications for the absolute event locations. Placing the 2006 event under a local maximum of overburden at 41.293°N, 129.105°E would imply a location of 41.299°N, 129.075°E for the January 2016 event, providing almost optimal overburden for the later four events.

Structural changes that occur upon photolysis of the Fe(II)a3 - CO complex in the cytochrome ba3-oxidase of Thermus thermophilus: A combined X-ray crystallographic and infrared spectral study demonstrates CO binding to CuB

PubMed Central

Liu, Bin; Zhang, Yang; Sage, J. Timothy; Soltis, S. Michael; Doukov, Tzanko; Chen, Ying; Stout, C. David; Fee, James A.

2012-01-01

The purpose of the work was to provide a crystallographic demonstration of the venerable idea that CO photolyzed from ferrous heme-a3 moves to the nearby cuprous ion in the cytochrome c oxidases. Crystal structures of CO-bound cytochrome ba3-oxidase from Thermus thermophilus, determined at ~ 2.8 – 3.2 Å resolution, reveal a Fe-C distance of ~2.0 Å, a Cu-O distance of 2.4 Å and a Fe-C-O angle of ~126°. Upon photodissociation at 100 K, X-ray structures indicate loss of Fea3-CO and appearance of CuB-CO having a Cu-C distance of ~1.9 Å and an O-Fe distance of ~2.3 Å. Absolute FTIR spectra recorded from single crystals of reduced ba3–CO that had not been exposed to X-ray radiation, showed several peaks around 1975 cm−1; after photolysis at 100 K, the absolute FTIR spectra also showed a significant peak at 2050 cm−1. Analysis of the “light’ minus ‘dark’ difference spectra showed four very sharp CO stretching bands at 1970 cm−1, 1977 cm−1, 1981 cm−1, and 1985 cm−1, previously assigned to the Fea3-CO complex, and a significantly broader CO stretching band centered at ~2050 cm−1, previously assigned to the CO stretching frequency of CuB bound CO. As expected for light propagating along the tetragonal axis of the P43212 space group, the single crystal spectra exhibit negligible dichroism. Absolute FTIR spectrometry of a CO-laden ba3 crystal, exposed to an amount of X-ray radiation required to obtain structural data sets before FTIR characterization, showed a significant signal due to photogenerated CO2 at 2337 cm−1 and one from traces of CO at 2133 cm−1; while bands associated with CO bound to either Fea3 or to CuB in “light” minus “dark” FTIR difference spectra shifted and broadened in response to X-ray exposure. In spite of considerable radiation damage to the crystals, both X-ray analysis at 2.8 and 3.2 Å and FTIR spectra support the long-held position that photolysis of Fea3-CO in cytochrome c oxidases leads to significant trapping of the CO on the CuB atom; Fea3 and CuB ligation, at the resolutions reported here, are otherwise unaltered. PMID:22226917

Prediction of Short-Distance Aerial Movement of Phakopsora pachyrhizi Urediniospores Using Machine Learning.

PubMed

Wen, L; Bowen, C R; Hartman, G L

2017-10-01

Dispersal of urediniospores by wind is the primary means of spread for Phakopsora pachyrhizi, the cause of soybean rust. Our research focused on the short-distance movement of urediniospores from within the soybean canopy and up to 61 m from field-grown rust-infected soybean plants. Environmental variables were used to develop and compare models including the least absolute shrinkage and selection operator regression, zero-inflated Poisson/regular Poisson regression, random forest, and neural network to describe deposition of urediniospores collected in passive and active traps. All four models identified distance of trap from source, humidity, temperature, wind direction, and wind speed as the five most important variables influencing short-distance movement of urediniospores. The random forest model provided the best predictions, explaining 76.1 and 86.8% of the total variation in the passive- and active-trap datasets, respectively. The prediction accuracy based on the correlation coefficient (r) between predicted values and the true values were 0.83 (P < 0.0001) and 0.94 (P < 0.0001) for the passive and active trap datasets, respectively. Overall, multiple machine learning techniques identified the most important variables to make the most accurate predictions of movement of P. pachyrhizi urediniospores short-distance.

Implications of an Absolute Simultaneity Theory for Cosmology and Universe Acceleration

PubMed Central

Kipreos, Edward T.

2014-01-01

An alternate Lorentz transformation, Absolute Lorentz Transformation (ALT), has similar kinematics to special relativity yet maintains absolute simultaneity in the context of a preferred reference frame. In this study, it is shown that ALT is compatible with current experiments to test Lorentz invariance only if the proposed preferred reference frame is locally equivalent to the Earth-centered non-rotating inertial reference frame, with the inference that in an ALT framework, preferred reference frames are associated with centers of gravitational mass. Applying this theoretical framework to cosmological data produces a scenario of universal time contraction in the past. In this scenario, past time contraction would be associated with increased levels of blueshifted light emissions from cosmological objects when viewed from our current perspective. The observation that distant Type Ia supernovae are dimmer than predicted by linear Hubble expansion currently provides the most direct evidence for an accelerating universe. Adjusting for the effects of time contraction on a redshift–distance modulus diagram produces a linear distribution of supernovae over the full redshift spectrum that is consistent with a non-accelerating universe. PMID:25536116

Implications of an absolute simultaneity theory for cosmology and universe acceleration.

PubMed

Kipreos, Edward T

2014-01-01

An alternate Lorentz transformation, Absolute Lorentz Transformation (ALT), has similar kinematics to special relativity yet maintains absolute simultaneity in the context of a preferred reference frame. In this study, it is shown that ALT is compatible with current experiments to test Lorentz invariance only if the proposed preferred reference frame is locally equivalent to the Earth-centered non-rotating inertial reference frame, with the inference that in an ALT framework, preferred reference frames are associated with centers of gravitational mass. Applying this theoretical framework to cosmological data produces a scenario of universal time contraction in the past. In this scenario, past time contraction would be associated with increased levels of blueshifted light emissions from cosmological objects when viewed from our current perspective. The observation that distant Type Ia supernovae are dimmer than predicted by linear Hubble expansion currently provides the most direct evidence for an accelerating universe. Adjusting for the effects of time contraction on a redshift-distance modulus diagram produces a linear distribution of supernovae over the full redshift spectrum that is consistent with a non-accelerating universe.

Application of Individualized Speed Thresholds to Interpret Position Specific Running Demands in Elite Professional Rugby Union: A GPS Study

PubMed Central

Reardon, Cillian; Tobin, Daniel P.; Delahunt, Eamonn

2015-01-01

A number of studies have used GPS technology to categorise rugby union locomotive demands. However, the utility of the results of these studies is confounded by small sample sizes, sub-elite player status and the global application of absolute speed thresholds to all player positions. Furthermore, many of these studies have used GPS units with low sampling frequencies. The aim of the present study was to compare and contrast the high speed running (HSR) demands of professional rugby union when utilizing micro-technology units sampling at 10 Hz and applying relative or individualised speed zones. The results of this study indicate that application of individualised speed zones results in a significant shift in the interpretation of the HSR demands of both forwards and backs and positional sub-categories therein. When considering the use of an absolute in comparison to an individualised HSR threshold, there was a significant underestimation for forwards of HSR distance (HSRD) (absolute = 269 ± 172.02, individualised = 354.72 ± 99.22, p < 0.001), HSR% (absolute = 5.15 ± 3.18, individualised = 7.06 ± 2.48, p < 0.001) and HSR efforts (HSRE) (absolute = 18.81 ± 12.25; individualised = 24.78 ± 8.30, p < 0.001). In contrast, there was a significant overestimation of the same HSR metrics for backs with the use of an absolute threshold (HSRD absolute = 697.79 ± 198.11, individualised = 570.02 ± 171.14, p < 0.001; HSR% absolute = 10.85 ± 2.82, individualised = 8.95 ± 2.76, p < 0.001; HSRE absolute = 41.55 ± 11.25; individualised = 34.54 ± 9.24, p < 0.001). This under- or overestimation associated with an absolute speed zone applies to varying degrees across the ten positional sub-categories analyzed and also to individuals within the same positional sub-category. The results of the present study indicated that although use of an individulised HSR threshold improves the interpretation of the HSR demands on a positional basis, inter-individual variability in maximum velocity within positional sub-categories means that players need to be considered on an individual basis to accurately gauge the HSR demands of rugby union. PMID:26208315

Wetting Properties of EMIIm & its Relevance to Electrospray Design

DTIC Science & Technology

2012-03-12

apparent surface area S Distance separating two grid apertures T Absolute temperature of the test liquid TC Critical temperature of the test liquid V...include the choice of solid materials being used as insulators, emitters or electrodes, thin film surface coatings that have a de- sired high or low...wettability, and changing the solid component surface roughness or temperature during operation.678 An electrospray thruster has been developed by

Limits and signatures of relativistic spaceflight

NASA Astrophysics Data System (ADS)

Yurtsever, Ulvi; Wilkinson, Steven

2018-01-01

While special relativity imposes an absolute speed limit at the speed of light, our Universe is not empty Minkowski spacetime. The constituents that fill the interstellar/intergalactic vacuum, including the cosmic microwave background photons, impose a lower speed limit on any object travelling at relativistic velocities. Scattering of cosmic microwave photons from an ultra-relativistic object may create radiation with a characteristic signature allowing the detection of such objects at large distances.

Performance of cardiopulmonary resuscitation feedback systems in a long-distance train with distributed traction.

PubMed

González-Otero, Digna M; de Gauna, Sofía Ruiz; Ruiz, Jesus; Rivero, Raquel; Gutierrez, J J; Saiz, Purificación; Russell, James K

2018-04-20

Out-of-hospital cardiac arrest is common in public locations, including public transportation sites. Feedback devices are increasingly being used to improve chest-compression quality. However, their performance during public transportation has not been studied yet. To test two CPR feedback devices representative of the current technologies (accelerometer and electromag- netic-field) in a long-distance train. Volunteers applied compressions on a manikin during the train route using both feedback devices. Depth and rate measurements computed by the devices were compared to the gold-standard values. Sixty-four 4-min records were acquired. The accelerometer-based device provided visual help in all experiments. Median absolute errors in depth and rate were 2.4 mm and 1.3 compressions per minute (cpm) during conventional speed, and 2.5 mm and 1.2 cpm during high speed. The electromagnetic-field-based device never provided CPR feedback; alert messages were shown instead. However, measurements were stored in its internal memory. Absolute errors for depth and rate were 2.6 mm and 0.7 cpm during conventional speed, and 2.6 mm and 0.7 cpm during high speed. Both devices were accurate despite the accelerations and the electromagnetic interferences induced by the train. However, the electromagnetic-field-based device would require modifications to avoid excessive alerts impeding feedback.

Chemistry of neutral species in the effluent of the micro atmospheric pressure plasma jet in water-helium admixture

NASA Astrophysics Data System (ADS)

Willems, Gert; Benedikt, Jan; von Keudell, Achim

2016-09-01

A thorough understanding and good control of produced neutral and charged species by cold atmospheric plasmas is essential for potential environmental and/or bio-medical applications. In this study we use the COST reference micro plasma jet (µ-APPJ), which is a radio-frequency capacitive coupled plasma source with 1 mm electrode distance, which has been operated in helium-water vapour mixture and has been studied as a potential source of hydroxyl radicals and hydrogen peroxide molecules. The water vapour concentration was up to 1.2%. Molecular Beam mass spectrometry is used as diagnostic tool. An absolute calibration of hydrogen peroxide was conducted using a double bubbler concept, because the ionization cross section for hydrogen peroxide is not available. Additionally the effluent chemistry was investigated by use of a 0D and 2D model. Absolute densities of hydrogen peroxide and hydroxyl radicals from atmospheric plasma will be presented. Their dependency on water vapour concentration in the carrier gas as well as distance to target have been investigated. The measured density is between 5E-13 cm-3 (2.4ppm) and 1.5E-14 cm-3 (7.2ppm) for both hydrogen peroxide molecules and hydroxyl radicals. The achieved results are in good agreement with other experiments.

Dust Production of Comet 21P/Giacobini-Zinner Using Broadband Photometry

NASA Technical Reports Server (NTRS)

Blaauw, R. C.; Suggs, R. M.; Cooke, W.

2012-01-01

Comet 21P/Giacobini-Zinner is a Jupiter family comet, approximately 2 km in diameter, and is established to be the parent of the Draconids, a meteor shower known to outburst. In 1933 and 1946 up to 10,000 meteors per hour were reported for the Draconids, and 2011 saw a minor Draconid outburst. Meteor stream modeling/forecasting being a primary focus for the NASA Meteoroid Environment Office, it was decided to monitor 21P for three purposes: firstly to find the apparent and absolute magnitude with respect to heliocentric distance; second to calculate Af , a quantity that describes the dust production rate and is used in models to predict the activity of the Draconids; and thirdly to detect possible increases in cometary activity, which could correspond to future Draconid meteor outbursts. A similar study was done for 21P during its 2004-2006 close approach to the Sun in which apparent and absolute magnitudes were found with various heliocentric distances, as well as the dust production. At 2.32 AU from the Sun, 21P possessed an apparent magnitude of 17.05 and Af of 83 cm, and an apparent magnitude of 15.91 and Af of 130.66 cm at 1.76 AU from the sun.

3D prostate MR-TRUS non-rigid registration using dual optimization with volume-preserving constraint

NASA Astrophysics Data System (ADS)

Qiu, Wu; Yuan, Jing; Fenster, Aaron

2016-03-01

We introduce an efficient and novel convex optimization-based approach to the challenging non-rigid registration of 3D prostate magnetic resonance (MR) and transrectal ultrasound (TRUS) images, which incorporates a new volume preserving constraint to essentially improve the accuracy of targeting suspicious regions during the 3D TRUS guided prostate biopsy. Especially, we propose a fast sequential convex optimization scheme to efficiently minimize the employed highly nonlinear image fidelity function using the robust multi-channel modality independent neighborhood descriptor (MIND) across the two modalities of MR and TRUS. The registration accuracy was evaluated using 10 patient images by calculating the target registration error (TRE) using manually identified corresponding intrinsic fiducials in the whole prostate gland. We also compared the MR and TRUS manually segmented prostate surfaces in the registered images in terms of the Dice similarity coefficient (DSC), mean absolute surface distance (MAD), and maximum absolute surface distance (MAXD). Experimental results showed that the proposed method with the introduced volume-preserving prior significantly improves the registration accuracy comparing to the method without the volume-preserving constraint, by yielding an overall mean TRE of 2:0+/-0:7 mm, and an average DSC of 86:5+/-3:5%, MAD of 1:4+/-0:6 mm and MAXD of 6:5+/-3:5 mm.

Hot and Hypoxic Environments Inhibit Simulated Soccer Performance and Exacerbate Performance Decrements When Combined

PubMed Central

Aldous, Jeffrey W. F.; Chrismas, Bryna C. R.; Akubat, Ibrahim; Dascombe, Ben; Abt, Grant; Taylor, Lee

2016-01-01

The effects of heat and/or hypoxia have been well-documented in match-play data. However, large match-to-match variation for key physical performance measures makes environmental inferences difficult to ascertain from soccer match-play. Therefore, the present study aims to investigate the hot (HOT), hypoxic (HYP), and hot-hypoxic (HH) mediated-decrements during a non-motorized treadmill based soccer-specific simulation. Twelve male University soccer players completed three familiarization sessions and four randomized crossover experimental trials of the intermittent Soccer Performance Test (iSPT) in normoxic-temperate (CON: 18°C 50% rH), HOT (30°C; 50% rH), HYP (1000 m; 18°C 50% rH), and HH (1000 m; 30°C; 50% rH). Physical performance and its performance decrements, body temperatures (rectal, skin, and estimated muscle temperature), heart rate (HR), arterial blood oxygen saturation (SaO2), perceived exertion, thermal sensation (TS), body mass changes, blood lactate, and plasma volume were all measured. Performance decrements were similar in HOT and HYP [Total Distance (−4%), High-speed distance (~−8%), and variable run distance (~−12%) covered] and exacerbated in HH [total distance (−9%), high-speed distance (−15%), and variable run distance (−15%)] compared to CON. Peak sprint speed, was 4% greater in HOT compared with CON and HYP and 7% greater in HH. Sprint distance covered was unchanged (p > 0.05) in HOT and HYP and only decreased in HH (−8%) compared with CON. Body mass (−2%), temperatures (+2–5%), and TS (+18%) were altered in HOT. Furthermore, SaO2 (−8%) and HR (+3%) were changed in HYP. Similar changes in body mass and temperatures, HR, TS, and SaO2 were evident in HH to HOT and HYP, however, blood lactate (p < 0.001) and plasma volume (p < 0.001) were only significantly altered in HH. Perceived exertion was elevated (p < 0.05) by 7% in all conditions compared with CON. Regression analysis identified that absolute TS and absolute rise in skin and estimated muscle temperature (r = 0.82, r = 0.84 r = 0.82, respectively; p < 0.05) predicted the hot-mediated-decrements in HOT. The hot, hypoxic, and hot-hypoxic environments impaired physical performance during iSPT. Future interventions should address the increases in TS and body temperatures, to attenuate these decrements on soccer performance. PMID:26793122

Benzo[b]naphthothiophenes and alkyl dibenzothiophenes: molecular tracers for oil migration distances

USGS Publications Warehouse

Li, Meijun; Wang, T.-G.; Shi, Shengbao; Liu, Keyu; Ellis, Geoffrey S.

2014-01-01

The secondary migration of petroleum is one of the most critical geological processes responsible for the accumulation of hydrocarbons in a sedimentary basin. Pyrrolic nitrogen compounds such as carbazoles and benzocarbazoles are thought to be practical molecular indicators for estimating relative migration distances of oil. In light oils or condensates, however, considerable analytical errors are usually caused by low concentrations of NSO-compounds. Here we show that polycyclic sulfur aromatic hydrocarbons such as dibenzothiophene, C1∼C3 alkylated dibenzothiophenes and benzo[b]naphthothiophenes, which are present in relatively higher concentrations than the pyrrolic nitrogen compounds, exhibit changes in both absolute and relative concentrations that correlate with migration distances. The polycyclic sulfur aromatic hydrocarbons related parameters — benzo[b]naphtho[2,1-d]thiophene/{benzo[b]naphtho[2,1-d]thiophene + benzo[b]naphtho[1,2-d]thiophene} (abbreviated as [2,1]BNT/([2,1]BNT+[1,2]BNT) and the concentration of total dibenzothiophenes plus benzo[b]naphthothiophenes — are proposed by this paper to trace the oil migration distances.

Confronting the Gaia and NLTE spectroscopic parallaxes for the FGK stars

NASA Astrophysics Data System (ADS)

Sitnova, Tatyana; Mashonkina, Lyudmila; Pakhomov, Yury

2018-04-01

The understanding of the chemical evolution of the Galaxy relies on the stellar chemical composition. Accurate atmospheric parameters is a prerequisite of determination of accurate chemical abundances. For late type stars with known distance, surface gravity (log g) can be calculated from well-known relation between stellar mass, T eff, and absolute bolometric magnitude. This method weakly depends on model atmospheres, and provides reliable log g. However, accurate distances are available for limited number of stars. Another way to determine log g for cool stars is based on ionisation equilibrium, i.e. consistent abundances from lines of neutral and ionised species. In this study we determine atmospheric parameters moving step-by-step from well-studied nearby dwarfs to ultra-metal poor (UMP) giants. In each sample, we select stars with the most reliable T eff based on photometry and the distance-based log g, and compare with spectroscopic gravity calculated taking into account deviations from local thermodinamic equilibrium (LTE). After that, we apply spectroscopic method of log g determination to other stars of the sample with unknown distances.

The population, magnitudes, and sizes of Jupiter family comets

NASA Astrophysics Data System (ADS)

Fernández, J. A.; Tancredi, G.; Rickman, H.; Licandro, J.

1999-12-01

We analyze the sample of measured nuclear magnitudes of the observed Jupiter family (JF) comets (taken as those with orbital periods P < 20 years and Tisserand parameters T > 2). We find a tendency of the measured nuclear magnitudes to be fainter as JF comets are observed with CCD detectors attached to medium- and large-size telescopes (e.g. Spacewatch Telescope). However, a few JF comets observed very far from the Sun (4-7 AU) show a wide dispersion of their derived absolute nuclear magnitudes which suggests that either these JF comets keep active all along the orbit, so the reported unusually bright distant magnitudes were strongly contaminated by a coma, or some of the measured ``nuclear magnitudes'' were grossly overestimated (i.e. their brightness underestimated). The cumulative mass distribution of JF comets is found to follow a power-law of index s = - 0.88 +/- 0.08, suggesting a distribution significantly steeper than that for both small main-belt asteroids and near-Earth asteroids. The cumulative mass distribution of JF comets with q < 2 AU tends to flatten for absolute (visual) nuclear magnitudes H_N > 16, which is probably due to incompleteness of discovery of fainter comets and/or a real scarcity of small comets due, perhaps, to much shorter physical lifetimes. In particular, no JF comets fainter than H_N ~ 19.5 are found in the sample, suggesting that the critical size for a comet to be still active may be of about 0.4 km radius for an assumed geometric albedo of 0.04. Possibly, smaller comet nuclei disintegrate very quickly into meteor streams. Most absolute nuclear magnitudes are found in the range 15-18, corresponding to nuclear radii in the range 0.8-3.3 km (for the same geometric albedo). We find that a large majority of JF comets with perihelion distances q > 2.5 AU are brighter than absolute nuclear magnitude H_N = 16, suggesting that only a very small fraction (a few percent) of the population of the JF comets with large q has so far been detected. A similar trend is noted for the corresponding absolute total magnitudes H_T taken from Kresák & Kresáková's (1994) catalog. By analyzing the H_N and H_T data, and trends in the discovery rate of JF comets as a function of their perihelion distances, the overall population of JF comets within Jupiter's region (q < 5.2 AU) up to an absolute nuclear magnitude H_N = 18.5 is estimated to be from several thousand to about 104 members. The q-distribution of JF comets shows a steep increase with q, which is consistent with JF comets coming from a flat intermediate source in the Jupiter-Saturn region.

Cross-Sectional Imaging in a Case of Adventitial Cystic Disease of the Popliteal Artery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ricci, Paolo; Panzetti, Claudio; Mastantuono, Marco

1999-01-15

Adventitial cystic disease of the popliteal artery is an unusual condition of uncertain etiology, in which a mucin-containing cyst forms in the wall of the artery and produces lower extremity claudication, typically in young and middle-aged men. A diagnosis of adventitial cystic disease of the popliteal artery was made preoperatively in a 47-year-old man by means of several imaging modalities, including angiography, magnetic resonance imaging, and ultrasound. The pathological findings confirmed the suggested diagnosis.

Measurement of the “Safe Zone” and the “Dangerous Zone” for the Screw Placement on the Quadrilateral Surface in the Treatment of Pelvic and Acetabular Fractures with Stoppa Approach by Computational 3D Technology

PubMed Central

Zhang, Sheng; Su, Wanhan; Luo, Qiang; Chen, Bin

2014-01-01

This study is aimed at definition of the safe and dangerous zone for screw placement with Stoppa approach for rapid identification during operation and a new way for the studies on the “safe zone.” Pelvic CT data of 84 human subjects were recruited to reconstruct the three-dimensional (3D) models. The distances between the edges of the “safe zone,” “dangerous zone,” and specific anatomic landmarks such as the obturator canal and the pelvic brim were precisely measured, respectively. The results show that the absolute “dangerous zone” was from the pelvic brim to 3.07 cm below it and within 2.86 cm of the obturator canal, while the region 3.56 cm below the pelvic brim or 3.85 cm away from the obturator canal was the absolute “safe zone” for screw placement. The region between the absolute “safe zone” and the absolute “dangerous zone” was the relatively “dangerous zone.” As a conclusion, application of computer-assisted 3D modeling techniques aids in the precise measurement of “safe zone” and “dangerous zone” in combination with Stoppa incision. It was not recommended to place screws on the absolute dangerous zone, while, for the relatively “dangerous zone,” it depends on the individual variations in bony anatomy and the fracture type. PMID:24605328

Lunar eclipse photometry: absolute luminance measurements and modeling.

PubMed

Hernitschek, Nina; Schmidt, Elmar; Vollmer, Michael

2008-12-01

The Moon's time-dependent luminance was determined during the 9 February 1990 and 3 March 2007 total lunar eclipses by using calibrated, industry standard photometers. After the results were corrected to unit air mass and to standard distances for both Moon and Sun, an absolute calibration was accomplished by using the Sun's known luminance and a pre-eclipse lunar albedo of approximately 13.5%. The measured minimum level of brightness in the total phase of both eclipses was relatively high, namely -3.32 m(vis) and -1.7 m(vis), which hints at the absence of pronounced stratospheric aerosol. The light curves were modeled in such a way as to let the Moon move through an artificial Earth shadow composed of a multitude of disk and ring zones, containing a relative luminance data set from an atmospheric radiative transfer calculation.

APOLLO: a quality assessment service for single and multiple protein models.

PubMed

Wang, Zheng; Eickholt, Jesse; Cheng, Jianlin

2011-06-15

We built a web server named APOLLO, which can evaluate the absolute global and local qualities of a single protein model using machine learning methods or the global and local qualities of a pool of models using a pair-wise comparison approach. Based on our evaluations on 107 CASP9 (Critical Assessment of Techniques for Protein Structure Prediction) targets, the predicted quality scores generated from our machine learning and pair-wise methods have an average per-target correlation of 0.671 and 0.917, respectively, with the true model quality scores. Based on our test on 92 CASP9 targets, our predicted absolute local qualities have an average difference of 2.60 Å with the actual distances to native structure. http://sysbio.rnet.missouri.edu/apollo/. Single and pair-wise global quality assessment software is also available at the site.

Method of excess fractions with application to absolute distance metrology: wavelength selection and the effects of common error sources.

PubMed

Falaggis, Konstantinos; Towers, David P; Towers, Catherine E

2012-09-20

Multiwavelength interferometry (MWI) is a well established technique in the field of optical metrology. Previously, we have reported a theoretical analysis of the method of excess fractions that describes the mutual dependence of unambiguous measurement range, reliability, and the measurement wavelengths. In this paper wavelength, selection strategies are introduced that are built on the theoretical description and maximize the reliability in the calculated fringe order for a given measurement range, number of wavelengths, and level of phase noise. Practical implementation issues for an MWI interferometer are analyzed theoretically. It is shown that dispersion compensation is best implemented by use of reference measurements around absolute zero in the interferometer. Furthermore, the effects of wavelength uncertainty allow the ultimate performance of an MWI interferometer to be estimated.

Redundant Sensors for Mobile Robot Navigation

DTIC Science & Technology

1985-09-01

represent a probability that the area is empty, while positive numbers mcan it’s probably occupied. Zero reprtsents the unknown. The basic idea is that...room to give it absolute positioning information. This works by using two infrared emitters and detectors on the robot. Measurements of anglcs are made...meters (T in Kelvin) 273 sec Distances returned when assuming 80 degrees Farenheit , but where. actual temperature is 60 degrees, will be seven inches

Canopus

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

The star α Carinae, named for the chief pilot of the fleet of Menelaos, who died in Egypt c. 1193 BC on the return from the Trojan War, the star being prominent at the time. It is the second brightest star, having an apparent magnitude of -0.62. It is a cream giant, spectral type F0Ib, at a distance of 326 light-years; its parallax is 0.010'', and it has an absolute magnitude of -5.6....

Photometry of Southern Hemisphere red dwarf stars

NASA Technical Reports Server (NTRS)

Weistrop, D.

1980-01-01

Results are presented for a photometric investigation of a spectroscopically selected sample of red dwarf stars in the Southern Hemisphere. Absolute magnitudes and distances for the stars are estimated from broadband red colors. Three stars which may be subluminous are identified, as are several stars which may be within 25 pc. The tangential velocity and velocity dispersion of the sample are similar to values found in other studies of nearby late-type stars.

VizieR Online Data Catalog: Improved reddenings for 59 Galactic Cepheids (Madore+, 2017)

NASA Astrophysics Data System (ADS)

Madore, B. F.; Freedman, W. L.; Moak, S.

2018-01-01

We have used a published compilation of absolute magnitudes measured in seven bands, based on distances and reddenings independently determined for 59 Galactic Cepheids (Fouque+ 2007, J/A+A/476/73), with overtone and suspected overtone pulsators omitted. Where available, HST parallaxes have been adopted for these stars, followed by Infrared Surface Brightness (IRSB) determinations and then Interferometric Baade-Wesselink applications and, finally, revised Hipparcos parallaxes. (1 data file).

A Precision Determination of the Effect of Metallicity on Cepheid Absolute Magnitudes in VIJHK Bands from Magellanic Cloud Cepheids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wielgórski, Piotr; Pietrzyński, Grzegorz; Zgirski, Bartłomiej

Using high-quality observed period–luminosity ( P – L ) relations in both Magellanic Clouds in the VIJHK s bands and optical and near-infrared Wesenheit indices, we determine the effect of metallicity on Cepheid P – L relations by comparing the relative distance between the LMC and SMC as determined from the Cepheids to the difference in distance between the Clouds that has been derived with very high accuracy from late-type eclipsing binary systems. Within an uncertainty of 3%, which is dominated by the uncertainty on the mean difference in metallicity between the Cepheid populations in the LMC and SMC, wemore » find metallicity effects smaller than 2% in all bands and in the Wesenheit indices, consistent with a zero metallicity effect. This result is valid for the metallicity range from −0.35 dex to −0.75 dex corresponding to the mean [Fe/H] values for classical Cepheids in the LMC and SMC, respectively. Yet most Cepheids in galaxies beyond the Local Group and located in the less crowded outer regions of these galaxies do fall into this metallicity regime, making our result important for applications to determine the distances to spiral galaxies well beyond the Local Group. Our result supports previous findings that indicated a very small metallicity effect on the near-infrared absolute magnitudes of classical Cepheids, and resolves the dispute about the size and sign of the metallicity effect in the optical spectral range. It also resolves one of the most pressing problems in the quest toward a measurement of the Hubble constant with an accuracy of 1% from the Cepheid–supernova Ia method.« less

Testing Metal-Poor Stellar Models and Isochrones with HST Parallaxes of Metal-Poor Stars

NASA Astrophysics Data System (ADS)

Chaboyer, B.; McArthur, B. E.; O'Malley, E.; Benedict, G. F.; Feiden, G. A.; Harrison, T. E.; McWilliam, A.; Nelan, E. P.; Patterson, R. J.; Sarajedini, A.

2017-02-01

Hubble Space Telescope (HST) fine guidance sensor observations were used to obtain parallaxes of eight metal-poor ([Fe/H] < -1.4) stars. The parallaxes of these stars determined by the new Hipparcos reduction average 17% accuracy, in contrast to our new HST parallaxes, which average 1% accuracy and have errors on the individual parallaxes ranging from 85 to 144 μas. These parallax data were combined with HST Advanced Camera for Surveys photometry in the F606W and F814W filters to obtain the absolute magnitudes of the stars with an accuracy of 0.02-0.03 mag. Six of these stars are on the main sequence (MS) (with -2.7 < [Fe/H] < -1.8) and are suitable for testing metal-poor stellar evolution models and determining the distances to metal-poor globular clusters (GCs). Using the abundances obtained by O’Malley et al., we find that standard stellar models using the VandenBerg & Clem color transformation do a reasonable job of matching five of the MS stars, with HD 54639 ([Fe/H] = -2.5) being anomalous in its location in the color-magnitude diagram. Stellar models and isochrones were generated using a Monte Carlo analysis to take into account uncertainties in the models. Isochrones that fit the parallax stars were used to determine the distances and ages of nine GCs (with -2.4 ≤ [Fe/H] ≤ -1.9). Averaging together the age of all nine clusters led to an absolute age of the oldest, most metal-poor GCs of 12.7 ± 1.0 Gyr, where the quoted uncertainty takes into account the known uncertainties in the stellar models and isochrones, along with the uncertainty in the distance and reddening of the clusters.

SU-G-JeP1-14: Respiratory Motion Tracking Using Kinect V2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silverstein, E; Snyder, M

Purpose: Investigate capability and accuracy of Kinect v2 camera for tracking respiratory motion to use as a tool during 4DCT or in combination with motion management during radiotherapy treatments. Methods: Utilizing the depth sensor on the Kinect as well as code written in C#, the respiratory motion of a patient was tracked by recording the depth (distance) values obtained at several points on the patient. Respiratory traces were also obtained using Varian’s RPM system, which traces the movement of a propriety marker placed on the patient’s abdomen, as well as an Anzai belt, which utilizes a pressure sensor to trackmore » respiratory motion. With the Kinect mounted 60 cm above the patient and pointing straight down, 11 breathing cycles were recorded with each system simultaneously. Relative displacement values during this time period were saved to file. While RPM and the Kinect give displacement values in distance units, the Anzai system has arbitrary units. As such, displacement for all three are displayed relative to the maximum value for the time interval from that system. Additional analysis was performed between RPM and Kinect for absolute displacement values. Results: Analysis of the data from all three systems indicates the relative motion obtained from the Kinect is both accurate and in sync with the data from RPM and Anzai. The absolute displacement data from RPM and Kinect show similar displacement values throughout the acquisition except for the depth obtained from the Kinect during maximum exhalation (largest distance from Kinect). Conclusion: By simply utilizing the depth data of specific points on a patient obtained from the Kinect, respiratory motion can be tracked and visualized with accuracy comparable to that of the Varian RPM and Anzai belt.« less

Segmentation of common carotid artery with active appearance models from ultrasound images

NASA Astrophysics Data System (ADS)

Yang, Xin; He, Wanji; Fenster, Aaron; Yuchi, Ming; Ding, Mingyue

2013-02-01

Carotid atherosclerosis is a major cause of stroke, a leading cause of death and disability. In this paper, a new segmentation method is proposed and evaluated for outlining the common carotid artery (CCA) from transverse view images, which were sliced from three-dimensional ultrasound (3D US) of 1mm inter-slice distance (ISD), to support the monitoring and assessment of carotid atherosclerosis. The data set consists of forty-eight 3D US images acquired from both left and right carotid arteries of twelve patients in two time points who had carotid stenosis of 60% or more at the baseline. The 3D US data were collected at baseline and three-month follow-up, where seven treated with 80mg atorvastatin and five with placebo. The baseline manual boundaries were used for Active Appearance Models (AAM) training; while the treatment data for segmentation testing and evaluation. The segmentation results were compared with experts manually outlined boundaries, as a surrogate for ground truth, for further evaluation. For the adventitia and lumen segmentations, the algorithm yielded Dice Coefficients (DC) of 92.06%+/-2.73% and 89.67%+/-3.66%, mean absolute distances (MAD) of 0.28+/-0.18 mm and 0.22+/-0.16 mm, maximum absolute distances (MAXD) of 0.71+/-0.28 mm and 0.59+/-0.21 mm, respectively. The segmentation results were also evaluated via Pratt's figure of merit (FOM) with the value of 0.61+/-0.06 and 0.66+/-0.05, which provides a quantitative measure for judging the similarity. Experimental results indicate that the proposed method can promote the carotid 3D US usage for a fast, safe and economical monitoring of the atherosclerotic disease progression and regression during therapy.

Dissipative and electrostatic force spectroscopy of indium arsenide quantum dots by non-contact atomic force microscopy

NASA Astrophysics Data System (ADS)

Stomp, Romain-Pierre

This thesis is devoted to the studies of self-assembled InAs quantum dots (QD) by low-temperature Atomic Force Microscopy (AFM) in frequency modulation mode. Several spectroscopic methods are developed to investigate single electron charging from a two-dimensional electron gas (2DEG) to an individual InAs QD. Furthermore, a new technique to measure the absolute tip-sample capacitance is also demonstrated. The main observables are the electrostatic force between the metal-coated AFM tip and sample as well as the sample-induced energy dissipation, and therefore no tunneling current has to be collected at the AFM tip. Measurements were performed by recording simultaneously the shift in the resonant frequency and the Q-factor degradation of the oscillating cantilever either as a function of tip-sample voltage or distance. The signature of single electron charging was detected as an abrupt change in the frequency shift as well as corresponding peaks in the dissipation. The main experimental features in the force agree well with the semi-classical theory of Coulomb blockade by considering the free energy of the system. The observed dissipation peaks can be understood as a back-action effect on the oscillating cantilever beam due to the fluctuation in time of electrons tunneling back and forth between the 2DEG and the QD. It was also possible to extract the absolute value of the tip-sample capacitance, as a consequence of the spectroscopic analysis of the electrostic force as a function of tip-sample distance for different values of the applied voltage. At the same time, the contact potential difference and the residual non-capacitive force could also be determined as a function of tip-sample distance.

A catalog of observed nuclear magnitudes of Jupiter family comets

NASA Astrophysics Data System (ADS)

Tancredi, G.; Fernández, J. A.; Rickman, H.; Licandro, J.

2000-10-01

A catalog of a sample of 105 Jupiter family (JF) comets (defined as those with Tisserand constants T > 2 and orbital periods P < 20 yr) is presented with our ``best estimates'' of their absolute nuclear magnitudes H_N = V(1,0,0). The catalog includes all the nuclear magnitudes reported after 1950 until August 1998 that appear in the International Comet Quarterly Archive of Cometary Photometric Data, the Minor Planet Center (MPC) data base, IAU Circulars, International Comet Quarterly, and a few papers devoted to some particular comets, together with our own observations. Photometric data previous to 1990 have mainly been taken from the Comet Light Curve Catalogue (CLICC) compiled by Kamél (\\cite{kamel}). We discuss the reliability of the reported nuclear magnitudes in relation to the inherent sources of errors and uncertainties, in particular the coma contamination often present even at large heliocentric distances. A large fraction of the JF comets of our sample indeed shows various degrees of activity at large heliocentric distances, which is correlated with recent downward jumps in their perihelion distances. The reliability of coma subtraction methods to compute the nuclear magnitude is also discussed. Most absolute nuclear magnitudes are found in the range 15 - 18, with no magnitudes fainter than H_N ~ 19.5. The catalog can be found at: http://www.fisica.edu.uy/ ~ gonzalo/catalog/. Table 2 and Appendix B are only available in electronic form at http://www.edpsciences.org Table 5 is also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

A LIGHT CURVE ANALYSIS OF CLASSICAL NOVAE: FREE-FREE EMISSION VERSUS PHOTOSPHERIC EMISSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hachisu, Izumi; Kato, Mariko, E-mail: hachisu@ea.c.u-tokyo.ac.jp, E-mail: mariko@educ.cc.keio.ac.jp

2015-01-10

We analyzed light curves of seven relatively slower novae, PW Vul, V705 Cas, GQ Mus, RR Pic, V5558 Sgr, HR Del, and V723 Cas, based on an optically thick wind theory of nova outbursts. For fast novae, free-free emission dominates the spectrum in optical bands rather than photospheric emission, and nova optical light curves follow the universal decline law. Faster novae blow stronger winds with larger mass-loss rates. Because the brightness of free-free emission depends directly on the wind mass-loss rate, faster novae show brighter optical maxima. In slower novae, however, we must take into account photospheric emission because of theirmore » lower wind mass-loss rates. We calculated three model light curves of free-free emission, photospheric emission, and their sum for various white dwarf (WD) masses with various chemical compositions of their envelopes and fitted reasonably with observational data of optical, near-IR (NIR), and UV bands. From light curve fittings of the seven novae, we estimated their absolute magnitudes, distances, and WD masses. In PW Vul and V705 Cas, free-free emission still dominates the spectrum in the optical and NIR bands. In the very slow novae, RR Pic, V5558 Sgr, HR Del, and V723 Cas, photospheric emission dominates the spectrum rather than free-free emission, which makes a deviation from the universal decline law. We have confirmed that the absolute brightnesses of our model light curves are consistent with the distance moduli of four classical novae with known distances (GK Per, V603 Aql, RR Pic, and DQ Her). We also discussed the reason why the very slow novae are about ∼1 mag brighter than the proposed maximum magnitude versus rate of decline relation.« less

Research and development of the laser tracker measurement system

NASA Astrophysics Data System (ADS)

Zhang, Z. L.; Zhou, W. H.; Lao, D. B.; Yuan, J.; Dong, D. F. F.; Ji, R. Y. Y.

2013-01-01

The working principle and system design of the laser tracker measurement system are introduced, as well as the key technologies and solutions in the implementation of the system. The design and implementation of the hardware and configuration of the software are mainly researched. The components of the hardware include distance measuring unit, angle measuring unit, tracking and servo control unit and electronic control unit. The distance measuring devices include the relative distance measuring device (IFM) and the absolute distance measuring device (ADM). The main component of the angle measuring device, the precision rotating stage, is mainly comprised of the precision axis and the encoders which are both set in the tracking head. The data processing unit, tracking and control unit and power supply unit are all set in the control box. The software module is comprised of the communication module, calibration and error compensation module, data analysis module, database management module, 3D display module and the man-machine interface module. The prototype of the laser tracker system has been accomplished and experiments have been carried out to verify the proposed strategies of the hardware and software modules. The experiments showed that the IFM distance measuring error is within 0.15mm, the ADM distance measuring error is within 3.5mm and the angle measuring error is within 3" which demonstrates that the preliminary prototype can realize fundamental measurement tasks.

A Calculation Method of Electric Distance and Subarea Division Application Based on Transmission Impedance

NASA Astrophysics Data System (ADS)

Fang, G. J.; Bao, H.

2017-12-01

The widely used method of calculating electric distances is sensitivity method. The sensitivity matrix is the result of linearization and based on the hypothesis that the active power and reactive power are decoupled, so it is inaccurate. In addition, it calculates the ratio of two partial derivatives as the relationship of two dependent variables, so there is no physical meaning. This paper presents a new method for calculating electrical distance, namely transmission impedance method. It forms power supply paths based on power flow tracing, then establishes generalized branches to calculate transmission impedances. In this paper, the target of power flow tracing is S instead of Q. Q itself has no direction and the grid delivers complex power so that S contains more electrical information than Q. By describing the power transmission relationship of the branch and drawing block diagrams in both forward and reverse directions, it can be found that the numerators of feedback parts of two block diagrams are all the transmission impedances. To ensure the distance is scalar, the absolute value of transmission impedance is defined as electrical distance. Dividing network according to the electric distances and comparing with the results of sensitivity method, it proves that the transmission impedance method can adapt to the dynamic change of system better and reach a reasonable subarea division scheme.

The Araucaria Project: The Distance to the Fornax Dwarf Galaxy from Near-infrared Photometry of RR Lyrae Stars

NASA Astrophysics Data System (ADS)

Karczmarek, Paulina; Pietrzyński, Grzegorz; Górski, Marek; Gieren, Wolfgang; Bersier, David

2017-12-01

We have obtained single-phase near-infrared (NIR) magnitudes in the J and K bands for 77 RR Lyrae (RRL) stars in the Fornax Dwarf Spheroidal Galaxy. We have used different theoretical and empirical NIR period-luminosity-metallicity calibrations for RRL stars to derive their absolute magnitudes, and found a true, reddening-corrected distance modulus of 20.818+/- 0.015{{(statistical)}}+/- 0.116{{(systematic)}} mag. This value is in excellent agreement with the results obtained within the Araucaria Project from the NIR photometry of red clump stars (20.858 ± 0.013 mag), the tip of the red giant branch (20.84+/- 0.04+/- 0.14 mag), as well as with other independent distance determinations to this galaxy. The effect of metallicity and reddening is substantially reduced in the NIR domain, making this method a robust tool for accurate distance determination at the 5% level. This precision is expected to reach the level of 3% once the zero points of distance calibrations are refined thanks to the Gaia mission. NIR period-luminosity-metallicity relations of RRL stars are particularly useful for distance determinations to galaxies and globular clusters up to 300 kpc, that lack young standard candles, like Cepheids. Based on data collected with the VLT/HAWK-I instrument at ESO Paranal Observatory, Chile, as a part of programme 082.D-0123(B).

Nonsurgically managed patients with degenerative spondylolisthesis: a 10- to 18-year follow-up study.

PubMed

Matsunaga, S; Ijiri, K; Hayashi, K

2000-10-01

Controversy exists concerning the indications for surgery and choice of surgical procedure for patients with degenerative spondylolisthesis. The goals of this study were to determine the clinical course of nonsurgically managed patients with degenerative spondylolisthesis as well as the indications for surgery. A total of 145 nonsurgically managed patients with degenerative spondylolisthesis were examined annually for a minimum of 10 years follow-up evaluation. Radiographic changes, changes in clinical symptoms, and functional prognosis were surveyed. Progressive spondylolisthesis was observed in 49 patients (34%). There was no correlation between changes in clinical symptoms and progression of spondylolisthesis. The intervertebral spaces of the slipped segments were decreased significantly in size during follow-up examination in patients in whom no progression was found. Low-back pain improved following a decrease in the total intervertebral space size. A total of 84 (76%) of 110 patients who had no neurological deficits at initial examination remained without neurological deficit after 10 years of follow up. Twenty-nine (83%) of the 35 patients who had neurological symptoms, such as intermittent claudication or vesicorectal disorder, at initial examination and refused surgery experienced neurological deterioration. The final prognosis for these patients was very poor. Low-back pain was improved by restabilization. Conservative treatment is useful for patients who have low-back pain with or without pain in the lower extremities. Surgical intervention is indicated for patients with neurological symptoms including intermittent claudication or vesicorectal disorder, provided that a good functional outcome can be achieved.

Current management of peripheral arterial occlusive disease: a review of pharmacologic agents and other interventions.

PubMed

Mannava, Krishna; Money, Samuel R

2007-01-01

Peripheral arterial occlusive disease (PAOD) of the lower extremities is becoming more prevalent worldwide. Nonsurgical treatment options provide the foundation for management. Lifestyle and risk factor modification should be emphasized in this patient population because of the associated adverse cardiovascular events. This includes implementation of a regular walking and smoking-cessation programs, aggressive control of hyperlipidemia, hypertension and diabetes mellitus, and treatment of hyperhomocysteinemia. Antiplatelet agents such as aspirin (acetylsalicylic acid) or clopidogrel are not specifically indicated for claudication but these drugs should be used in all patients with PAOD to prevent secondary ischemic events. Currently, cilostazol is the only US FDA approved agent that appears effective for the treatment of claudication symptoms. Several agents have been used with success outside of the US and others are still undergoing testing. Definitive recommendations cannot be made on the use of these drugs until further evaluation is completed. Ongoing research with new strategies for angiogenesis and the use of progenitor cells has yielded encouraging results, particularly for patients with critical limb ischemia and limited options. Advances in endovascular technology over the last several years have greatly enhanced the ability to diagnose and treat specific anatomic lesions that previously would have required open surgical correction. The use of percutaneous transluminal angioplasty and stents in the lower extremities has had considerable success when following specific guidelines such as those set forth by the TransAtlantic Inter-Society Consensus Working Group.

Relationship Between Central and Peripheral Atherosclerosis and Left Ventricular Dysfunction in a Community Population

PubMed Central

Tsao, Connie W.; Gona, Philimon; Salton, Carol; Murabito, Joanne M.; Oyama, Noriko; Danias, Peter G.; O’Donnell, Christopher J.; Manning, Warren J.; Yeon, Susan B.

2011-01-01

We aimed to determine the relationships between resting left ventricular (LV) wall motion abnormalities (WMAs), aortic plaque, and PAD in a community cohort. 1726 Framingham Heart Study Offspring Cohort participants (806 males, 65±9 years) underwent cardiovascular magnetic resonance with quantification of aortic plaque volume and assessment of regional LV systolic function. Claudication, lower extremity revascularization, and ankle-brachial index (ABI) were recorded at Examination 7. WMAs were associated with greater aortic plaque burden, decreased ABI, and claudication in age- and sex-adjusted analyses (all p<0.001), which were not significant after adjustment for cardiovascular risk factors. In age- and sex-adjusted analyses, both the presence (p<0.001) and volume of aortic plaque were associated with decreased ABI (p<0.001). After multivariable adjustment, ABI≤0.9 or prior revascularization was associated with a three-fold odds of aortic plaque (p=0.0083). Plaque volume significantly increased with decreasing ABI in multivariable-adjusted analyses (p<0.0001). In this free-living population, associations of WMAs with aortic plaque burden and clinical measures of PAD were attenuated after adjustment for coronary heart disease risk factors. Aortic plaque volume and ABI remained strongly negatively correlated after multivariable adjustment. Our findings suggest that the association between coronary heart disease and non-coronary atherosclerosis is explained by cardiovascular risk factors. Aortic atherosclerosis and PAD remain strongly associated after multivariable adjustment suggesting shared mechanisms beyond those captured by traditional risk factors. PMID:21708875

The ClaudicatioNet concept: design of a national integrated care network providing active and healthy aging for patients with intermittent claudication.

PubMed

Lauret, Gert-Jan; Gijsbers, Harm J H; Hendriks, Erik J M; Bartelink, Marie-Louise; de Bie, Rob A; Teijink, Joep A W

2012-01-01

Intermittent claudication (IC) is a manifestation of peripheral arterial occlusive disease (PAOD). Besides cardiovascular risk management, supervised exercise therapy (SET) should be offered to all patients with IC. Outdated guidelines, an insufficient number of specialized physiotherapists (PTs), lack of awareness of the importance of SET by referring physicians, and misguided financial incentives all seriously impede the availability of a structured SET program in The Netherlands. By initiating regional care networks, ClaudicatioNet aims to improve the quality of care for patients with IC. Based on the chronic care model as a conceptual framework, these networks should enhance the access, continuity, and (cost) efficiency of the health care system. With the aid of a national database, health care professionals will be able to benchmark patient results while ClaudicatioNet will be able to monitor quality of care by way of functional and patient reported outcome measures. The success of ClaudicatioNet is dependent on several factors. Vascular surgeons, general practitioners and coordinating central caregivers will need to team up and work in close collaboration with specialized PTs. A substantial task in the upcoming years will be to monitor the quality, volume, and distribution of ClaudicatioNet PTs. Finally, misguided financial incentives within the Dutch health care system need to be tackled. With ClaudicatioNet, integrated care pathways are likely to improve in the upcoming years. This should result in the achievement of optimal quality of care for all patients with IC.

Cooperation under predation risk: experiments on costs and benefits

PubMed Central

Milinski, M.; Lüthi, J. H.; Eggler, R.; Parker, G. A.

1997-01-01

Two fish that cooperatively inspect a predator may have negotiated the share of the risk that each takes. A test of both the costs of predator inspection dependent on the distance from which the predator is approached and the potential benefits of cooperation was carried out strictly experimentally. We made either singletons or pairs of dead sticklebacks, Gasterosteus aculeatus, approach hungry pike, Esox lucius, by remote control according to an algorithm that mimicked natural inspection. The predation risk of both single inspectors and parallel inspecting pairs increased with closer inspection distances. A member of an inspecting pair had only about half the risk of that of a single inspector. In pairs, a companion diluted the lead fish's risk of being caught, depending on its distance behind the leader. The absolute risk difference between leader and follower was greatest for close inspection distances and decreased further away from the predator. The leader's relative risk increased with its distance ahead of the laggard. However, for a given distance between leader and laggard, the relative risks of the two fish remained similar with distance from the predator. The cost side of the inequalities that define a 'Prisoner's Dilemma' has thus been measured for this system. In a second experiment the 'attack deterrence hypothesis' of predator inspection (i.e. inspection decreases attack probability) was tested. The pike was offered a choice between two sticklebacks, one of which had carried out a predator inspection visit. There was no indication of attack deterrence through predator inspection.

Cooperation under Predation Risk: Experiments on Costs and Benefits

NASA Astrophysics Data System (ADS)

Milinski, Manfred; Luthi, Jean H.; Eggler, Rolf; Parker, Geoffrey A.

1997-06-01

Two fish that cooperatively inspect a predator may have negotiated the share of the risk that each takes. A test of both the costs of predator inspection dependent on the distance from which the predator is approached and the potential benefits of cooperation was carried out strictly experimentally. We made either singletons or pairs of dead sticklebacks, Gasterosteus aculeatus, approach hungry pike, Esox lucius, by remote control according to an algorithm that mimicked natural inspection. The predation risk of both single inspectors and parallel inspecting pairs increased with closer inspection distances. A member of an inspecting pair had only about half the risk of that of a single inspector. In pairs, a companion diluted the lead fish's risk of being caught, depending on its distance behind the leader. The absolute risk difference between leader and follower was greatest for close inspection distances and decreased further away from the predator. The leader's relative risk increased with its distance ahead of the laggard. However, for a given distance between leader and laggard, the relative risks to the two fish remained similar with distance from the predator. The cost side of the inequalities that define a 'Prisoner's Dilemma' has thus been measured for this system. In a second experiment the 'attack deterrence hypothesis' of predator inspection (i.e. inspection decreases attack probability) was tested. The pike was offered a choice between two sticklebacks, one of which had carried out a predator inspection visit. There was no indication of attack deterrence through predator inspection.

Simulated environmental transport distances of Lepeophtheirus salmonis in Loch Linnhe, Scotland, for informing aquaculture area management structures.

PubMed

Salama, N K G; Murray, A G; Rabe, B

2016-04-01

In the majority of salmon farming countries, production occurs in zones where practices are coordinated to manage disease agents such as Lepeophtheirus salmonis. To inform the structure of zones in specific systems, models have been developed accounting for parasite biology and system hydrodynamics. These models provide individual system farm relationships, and as such, it may be beneficial to produce more generalized principles for informing structures. Here, we use six different forcing scenarios to provide simulations from a previously described model of the Loch Linnhe system, Scotland, to assess the maximum dispersal distance of lice particles released from 12 sites transported over 19 day. Results indicate that the median distance travelled is 6.1 km from release site with <2.5% transported beyond 15 km, which occurs from particles originating from half of the release sites, with an absolute simulated distance of 36 km observed. This provides information suggesting that the disease management areas developed for infectious salmon anaemia control may also have properties appropriate for salmon lice management in Scottish coastal waters. Additionally, general numerical descriptors of the simulated relative lice abundance reduction with increased distance from release location are proposed. © 2015 Crown copyright. © 2015 John Wiley & Sons Ltd.

Contact-free calibration of an asymmetric multi-layer interferometer for the surface force balance

NASA Astrophysics Data System (ADS)

Balabajew, Marco; van Engers, Christian D.; Perkin, Susan

2017-12-01

The Surface Force Balance (SFB, also known as Surface Force Apparatus, SFA) has provided important insights into many phenomena within the field of colloid and interface science. The technique relies on using white light interferometry to measure the distance between surfaces with sub-nanometer resolution. Up until now, the determination of the distance between the surfaces required a so-called "contact calibration," an invasive procedure during which the surfaces are brought into mechanical contact. This requirement for a contact calibration limits the range of experimental systems that can be investigated with SFB, for example, it precludes experiments with substrates that would be irreversibly modified or damaged by mechanical contact. Here we present a non-invasive method to measure absolute distances without performing a contact calibration. The method can be used for both "symmetric" and "asymmetric" systems. We foresee many applications for this general approach including, most immediately, experiments using single layer graphene electrodes in the SFB which may be damaged when brought into mechanical contact.

Mental Representation of Spatial Cues During Spaceflight (3D-SPACE)

NASA Astrophysics Data System (ADS)

Clement, Gilles; Lathan, Corinna; Skinner, Anna; Lorigny, Eric

2008-06-01

The 3D-SPACE experiment is a joint effort between ESA and NASA to develop a simple virtual reality platform to enable astronauts to complete a series of tests while aboard the International Space Station (ISS). These tests will provide insights into the effects of the space environment on: (a) depth perception, by presenting 2D geometric illusions and 3D objects that subjects adjust with a finger trackball; (b) distance perception, by presenting natural or computer-generated 3D scenes where subjects estimate and report absolute distances or adjust distances; and (c) handwriting/drawing, by analyzing trajectories and velocities when subjects write or draw memorized objects with an electronic pen on a digitizing tablet. The objective of these tasks is to identify problems associated with 3D perception in astronauts with the goal of developing countermeasures to alleviate any associated performance risks. The equipment has been uploaded to the ISS in April 2008, and the first measurements should take place during Increment 17.

A Wireless Sensor Network with Soft Computing Localization Techniques for Track Cycling Applications.

PubMed

Gharghan, Sadik Kamel; Nordin, Rosdiadee; Ismail, Mahamod

2016-08-06

In this paper, we propose two soft computing localization techniques for wireless sensor networks (WSNs). The two techniques, Neural Fuzzy Inference System (ANFIS) and Artificial Neural Network (ANN), focus on a range-based localization method which relies on the measurement of the received signal strength indicator (RSSI) from the three ZigBee anchor nodes distributed throughout the track cycling field. The soft computing techniques aim to estimate the distance between bicycles moving on the cycle track for outdoor and indoor velodromes. In the first approach the ANFIS was considered, whereas in the second approach the ANN was hybridized individually with three optimization algorithms, namely Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), and Backtracking Search Algorithm (BSA). The results revealed that the hybrid GSA-ANN outperforms the other methods adopted in this paper in terms of accuracy localization and distance estimation accuracy. The hybrid GSA-ANN achieves a mean absolute distance estimation error of 0.02 m and 0.2 m for outdoor and indoor velodromes, respectively.

A Wireless Sensor Network with Soft Computing Localization Techniques for Track Cycling Applications

PubMed Central

Gharghan, Sadik Kamel; Nordin, Rosdiadee; Ismail, Mahamod

2016-01-01

In this paper, we propose two soft computing localization techniques for wireless sensor networks (WSNs). The two techniques, Neural Fuzzy Inference System (ANFIS) and Artificial Neural Network (ANN), focus on a range-based localization method which relies on the measurement of the received signal strength indicator (RSSI) from the three ZigBee anchor nodes distributed throughout the track cycling field. The soft computing techniques aim to estimate the distance between bicycles moving on the cycle track for outdoor and indoor velodromes. In the first approach the ANFIS was considered, whereas in the second approach the ANN was hybridized individually with three optimization algorithms, namely Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), and Backtracking Search Algorithm (BSA). The results revealed that the hybrid GSA-ANN outperforms the other methods adopted in this paper in terms of accuracy localization and distance estimation accuracy. The hybrid GSA-ANN achieves a mean absolute distance estimation error of 0.02 m and 0.2 m for outdoor and indoor velodromes, respectively. PMID:27509495

Long-term Durability of Infrainguinal Endovascular and Open Revascularization for Disabling Claudication.

PubMed

Khan, Sikandar Z; Rivero, Mariel; Cherr, Gregory S; Harris, Linda M; Dryjski, Maciej L; Dosluoglu, Hasan H

2018-05-15

Infrainguinal revascularization for disabling claudication (DC) is frequently performed, but long-term results are still unknown. In this study, we compared clinical outcomes of infrainguinal endovascular (EV) and open interventions for DC after the failure of medical management. One hundred ninety-four patients with DC (Rutherford category 3) who had open (n = 53) or EV (n = 141) interventions were grouped as open-great saphenous vein (GSV) (n = 21), open-prosthetic (n = 32), EV-Trans-Atlantic Inter-Society Consensus II (TASC II) A and B (AB) (n = 48), and EV-TASC II C and D (CD) (n = 93). Patency, primary clinical success (PCS; sustained improvement in symptoms without reintervention), and secondary clinical success (SCS; sustained improvement in symptoms with reintervention) rates were compared. Mean follow-up was 57 ± 33 months. Five-year primary patency was 58% in open-GSV, 40% in open-prosthetic, 72% in EV-AB, and 38% in EV-CD (P < 0.001). Five-year secondary patency was 77% in open-GSV, 50% in open-prosthetic, 96% in EV-AB, and 61% in EV-CD (P < 0.001). Freedom from major adverse limb events was 73% in open-GSV, 77% in EV-AB, 70% in EV-CD, and 67% in open-prosthetic (P = 0.279). Five-year PCS was 46% in open-GSV, 40% in open-prosthetic, 57% in EV-AB, and 44% in EV-CD (P = 0.02). Five-year SCS was 78% in open-GSV, 78% in open-prosthetic, 85% in EV-AB, and 84% in EV-CD (P = 0.732). A total of 116 reinterventions were performed, 10 in 6 limbs (27%) in open-GSV, 18 in 12 limbs (36%) in open-prosthetic, 26 in 15 limbs (24%) in EV-AB, and 62 in 39 limbs (36%) in EV-CD. Reinterventions included 71 (61%) EV and 45 (39%) open procedures. Durability of infrainguinal interventions in claudicants depends mainly on anatomic complexity of disease. Good long-term clinical success can be achieved with both open and EV interventions, albeit with high reintervention rates, especially in patients with TASC II C and D disease. A considerable subset of EV patients will eventually require surgical revascularization to maintain clinical benefit. In this study, almost 20% of patients undergoing EV for TASC II C and D disease eventually required surgical bypass. Copyright © 2018 Elsevier Inc. All rights reserved.

Graft extrusion in both the coronal and sagittal planes is greater after medial compared with lateral meniscus allograft transplantation but is unrelated to early clinical outcomes.

PubMed

Lee, Dae-Hee; Lee, Chang-Rack; Jeon, Jin-Ho; Kim, Kyung-Ah; Bin, Seong-Il

2015-01-01

Graft extrusion after meniscus allograft transplantation (MAT) may be affected by horn fixation, which differs between medial and lateral MAT. Few studies have compared graft extrusion, especially sagittal extrusion, after medial and lateral MAT. In patients undergoing medial and lateral MAT, graft extrusion is likely similar and not correlated with postoperative Lysholm scores. Cohort study; Level of evidence, 2. Meniscus graft extrusion in the coronal and sagittal planes was compared in 51 knees undergoing medial MAT and 84 undergoing lateral MAT. Distances from the anterior and posterior articular cartilage margins to the anterior (anterior cartilage meniscus distance [ACMD]) and posterior (posterior cartilage meniscus distance [PCMD]) horns, respectively, were assessed on immediate postoperative magnetic resonance imaging and compared in patients undergoing medial and lateral MAT. Correlations between coronal and sagittal graft extrusion and between extrusion and the Lysholm score were compared in the 2 groups. In the coronal plane, mean absolute (4.3 vs 2.7 mm, respectively; P<.001) and relative (39% vs 21%, respectively; P<.001) graft extrusions were significantly greater for medial than lateral MAT. In the sagittal plane, mean absolute and relative ACMD and PCMD values were significantly greater for medial than lateral MAT (P<.001 each). For both medial and lateral MAT, mean absolute and relative ACMDs were significantly larger than PCMDs (P<.001 each). Graft extrusion>3 mm in the coronal plane was significantly more frequent in the medial (78%) than in the lateral (35%) MAT group. In the sagittal plane, the frequencies of ACMDs (72% vs 39%, respectively) and PCMDs (23% vs 4%, respectively) >3 mm were also significantly greater in the medial than in the lateral MAT group. Coronal and sagittal extrusions were not correlated with postoperative Lysholm scores for both medial and lateral MAT. The amount and incidence of graft extrusion were greater after medial than lateral MAT in both the coronal and sagittal planes. In the sagittal plane, graft extrusion was greater and more frequent on the anterior than the posterior horn in both medial and lateral MAT. However, graft extrusion was not correlated with early clinical outcomes after both medial and lateral MAT. © 2014 The Author(s).

Laser Truss Sensor for Segmented Telescope Phasing

NASA Technical Reports Server (NTRS)

Liu, Duncan T.; Lay, Oliver P.; Azizi, Alireza; Erlig, Herman; Dorsky, Leonard I.; Asbury, Cheryl G.; Zhao, Feng

2011-01-01

A paper describes the laser truss sensor (LTS) for detecting piston motion between two adjacent telescope segment edges. LTS is formed by two point-to-point laser metrology gauges in a crossed geometry. A high-resolution (<30 nm) LTS can be implemented with existing laser metrology gauges. The distance change between the reference plane and the target plane is measured as a function of the phase change between the reference and target beams. To ease the bandwidth requirements for phase detection electronics (or phase meter), homodyne or heterodyne detection techniques have been used. The phase of the target beam also changes with the refractive index of air, which changes with the air pressure, temperature, and humidity. This error can be minimized by enclosing the metrology beams in baffles. For longer-term (weeks) tracking at the micron level accuracy, the same gauge can be operated in the absolute metrology mode with an accuracy of microns; to implement absolute metrology, two laser frequencies will be used on the same gauge. Absolute metrology using heterodyne laser gauges is a demonstrated technology. Complexity of laser source fiber distribution can be optimized using the range-gated metrology (RGM) approach.

Conception and realization of a parallel-plate free-air ionization chamber for the absolute dosimetry of an ultrasoft X-ray beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Groetz, J.-E., E-mail: jegroetz@univ-fcomte.fr; Mavon, C.; Fromm, M.

2014-08-15

We report the design of a millimeter-sized parallel plate free-air ionization chamber (IC) aimed at determining the absolute air kerma rate of an ultra-soft X-ray beam (E = 1.5 keV). The size of the IC was determined so that the measurement volume satisfies the condition of charged-particle equilibrium. The correction factors necessary to properly measure the absolute kerma using the IC have been established. Particular attention was given to the determination of the effective mean energy for the 1.5 keV photons using the PENELOPE code. Other correction factors were determined by means of computer simulation (COMSOL™and FLUKA). Measurements of airmore » kerma rates under specific operating parameters of the lab-bench X-ray source have been performed at various distances from that source and compared to Monte Carlo calculations. We show that the developed ionization chamber makes it possible to determine accurate photon fluence rates in routine work and will constitute substantial time-savings for future radiobiological experiments based on the use of ultra-soft X-rays.« less

The Segue K giant survey. II. A catalog of distance determinations for the Segue K giants in the galactic halo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xue, Xiang-Xiang; Rix, Hans-Walter; Ma, Zhibo

2014-04-01

We present an online catalog of distance determinations for 6036 K giants, most of which are members of the Milky Way's stellar halo. Their medium-resolution spectra from the Sloan Digital Sky Survey/Sloan Extension for Galactic Understanding and Exploration are used to derive metallicities and rough gravity estimates, along with radial velocities. Distance moduli are derived from a comparison of each star's apparent magnitude with the absolute magnitude of empirically calibrated color-luminosity fiducials, at the observed (g – r){sub 0} color and spectroscopic [Fe/H]. We employ a probabilistic approach that makes it straightforward to properly propagate the errors in metallicities, magnitudes,more » and colors into distance uncertainties. We also fold in prior information about the giant-branch luminosity function and the different metallicity distributions of the SEGUE K-giant targeting sub-categories. We show that the metallicity prior plays a small role in the distance estimates, but that neglecting the luminosity prior could lead to a systematic distance modulus bias of up to 0.25 mag, compared to the case of using the luminosity prior. We find a median distance precision of 16%, with distance estimates most precise for the least metal-poor stars near the tip of the red giant branch. The precision and accuracy of our distance estimates are validated with observations of globular and open clusters. The stars in our catalog are up to 125 kpc from the Galactic center, with 283 stars beyond 50 kpc, forming the largest available spectroscopic sample of distant tracers in the Galactic halo.« less

Angles-Only Navigation: Position and Velocity Solution from Absolute Triangulation

DTIC Science & Technology

2011-01-01

geocentric position vectors. Using two vectors derived from each such observation (see next section), a solution for a portion of the boat’s track was...t)x0 describes the curvature of the path in the direction x 0, which, for a geocentric coordinate system and /(t) < 0, will be toward the center of...finite distances, with geocentric coordinates known to a meter or better (readily available on the Internet) a straightfor- ward triangulation method

Distances of Dwarf Carbon Stars

NASA Astrophysics Data System (ADS)

Harris, Hugh C.; Dahn, Conard C.; Subasavage, John P.; Munn, Jeffrey A.; Canzian, Blaise J.; Levine, Stephen E.; Monet, Alice B.; Pier, Jeffrey R.; Stone, Ronald C.; Tilleman, Trudy M.; Hartkopf, William I.

2018-06-01

Parallaxes are presented for a sample of 20 nearby dwarf carbon stars. The inferred luminosities cover almost two orders of magnitude. Their absolute magnitudes and tangential velocities confirm prior expectations that some originate in the Galactic disk, although more than half of this sample are halo stars. Three stars are found to be astrometric binaries, and orbital elements are determined; their semimajor axes are 1–3 au, consistent with the size of an AGB mass-transfer donor star.

Coronal propagation of flare associated electrons and protons

NASA Technical Reports Server (NTRS)

Schellert, G.; Wibberenz, G.; Kunow, H.

1985-01-01

A statistical study of characteristic times and intensities of 36 solar particle events observed between 1977 and 1979 by the Kiel Cosmic Ray Experiment on board HELIOS-1 and -2 has been carried out. For approx. 0.5 MeV electrons we order the times of maximum and the absolute intensities with respect to angular distance from the parent flare. Discussion of coronal parameters in terms of Reid's model leads to typical time constants for coronal diffusion and escape.

Turbulent mass inhomogeneities induced by a point-source

NASA Astrophysics Data System (ADS)

Thalabard, Simon

2018-03-01

We describe how turbulence distributes tracers away from a localized source of injection, and analyze how the spatial inhomogeneities of the concentration field depend on the amount of randomness in the injection mechanism. For that purpose, we contrast the mass correlations induced by purely random injections with those induced by continuous injections in the environment. Using the Kraichnan model of turbulent advection, whereby the underlying velocity field is assumed to be shortly correlated in time, we explicitly identify scaling regions for the statistics of the mass contained within a shell of radius r and located at a distance ρ away from the source. The two key parameters are found to be (i) the ratio s 2 between the absolute and the relative timescales of dispersion and (ii) the ratio Λ between the size of the cloud and its distance away from the source. When the injection is random, only the former is relevant, as previously shown by Celani et al (2007 J. Fluid Mech. 583 189–98) in the case of an incompressible fluid. It is argued that the space partition in terms of s 2 and Λ is a robust feature of the injection mechanism itself, which should remain relevant beyond the Kraichnan model. This is for instance the case in a generalized version of the model, where the absolute dispersion is prescribed to be ballistic rather than diffusive.

The VMC survey - XXVI. Structure of the Small Magellanic Cloud from RR Lyrae stars

NASA Astrophysics Data System (ADS)

Muraveva, T.; Subramanian, S.; Clementini, G.; Cioni, M.-R. L.; Palmer, M.; van Loon, J. Th.; Moretti, M. I.; de Grijs, R.; Molinaro, R.; Ripepi, V.; Marconi, M.; Emerson, J.; Ivanov, V. D.

2018-01-01

We present results from the analysis of 2997 fundamental mode RR Lyrae variables located in the Small Magellanic Cloud (SMC). For these objects, near-infrared time series photometry from the VISTA survey of the Magellanic Clouds system (VMC) and visual light curves from the OGLE IV (Optical Gravitational Lensing Experiment IV) survey are available. In this study, the multi-epoch Ks-band VMC photometry was used for the first time to derive intensity-averaged magnitudes of the SMC RR Lyrae stars. We determined individual distances to the RR Lyrae stars from the near-infrared period-absolute magnitude-metallicity (PM_{K_s}Z) relation, which has some advantages in comparison with the visual absolute magnitude-metallicity (MV-[Fe/H]) relation, such as a smaller dependence of the luminosity on interstellar extinction, evolutionary effects and metallicity. The distances we have obtained were used to study the three-dimensional structure of the SMC. The distribution of the SMC RR Lyrae stars is found to be ellipsoidal. The actual line-of-sight depth of the SMC is in the range 1-10 kpc, with an average depth of 4.3 ± 1.0 kpc. We found that RR Lyrae stars in the eastern part of the SMC are affected by interactions of the Magellanic Clouds. However, we do not see a clear bimodality observed for red clump stars, in the distribution of RR Lyrae stars.

A Double-difference Earthquake location algorithm: Method and application to the Northern Hayward Fault, California

USGS Publications Warehouse

Waldhauser, F.; Ellsworth, W.L.

2000-01-01

We have developed an efficient method to determine high-resolution hypocenter locations over large distances. The location method incorporates ordinary absolute travel-time measurements and/or cross-correlation P-and S-wave differential travel-time measurements. Residuals between observed and theoretical travel-time differences (or double-differences) are minimized for pairs of earthquakes at each station while linking together all observed event-station pairs. A least-squares solution is found by iteratively adjusting the vector difference between hypocentral pairs. The double-difference algorithm minimizes errors due to unmodeled velocity structure without the use of station corrections. Because catalog and cross-correlation data are combined into one system of equations, interevent distances within multiplets are determined to the accuracy of the cross-correlation data, while the relative locations between multiplets and uncorrelated events are simultaneously determined to the accuracy of the absolute travel-time data. Statistical resampling methods are used to estimate data accuracy and location errors. Uncertainties in double-difference locations are improved by more than an order of magnitude compared to catalog locations. The algorithm is tested, and its performance is demonstrated on two clusters of earthquakes located on the northern Hayward fault, California. There it colapses the diffuse catalog locations into sharp images of seismicity and reveals horizontal lineations of hypocenter that define the narrow regions on the fault where stress is released by brittle failure.

Effect of genomic distance on coexpression of coregulated genes in E. coli

PubMed Central

Merino, Enrique; Marchal, Kathleen; Collado-Vides, Julio

2017-01-01

In prokaryotes, genomic distance is a feature that in addition to coregulation affects coexpression. Several observations, such as genomic clustering of highly coexpressed small regulons, support the idea that coexpression behavior of coregulated genes is affected by the distance between the coregulated genes. However, the specific contribution of distance in addition to coregulation in determining the degree of coexpression has not yet been studied systematically. In this work, we exploit the rich information in RegulonDB to study how the genomic distance between coregulated genes affects their degree of coexpression, measured by pairwise similarity of expression profiles obtained under a large number of conditions. We observed that, in general, coregulated genes display higher degrees of coexpression as they are more closely located on the genome. This contribution of genomic distance in determining the degree of coexpression was relatively small compared to the degree of coexpression that was determined by the tightness of the coregulation (degree of overlap of regulatory programs) but was shown to be evolutionary constrained. In addition, the distance effect was sufficient to guarantee coexpression of coregulated genes that are located at very short distances, irrespective of their tightness of coregulation. This is partly but definitely not always because the close distance is also the cause of the coregulation. In cases where it is not, we hypothesize that the effect of the distance on coexpression could be caused by the fact that coregulated genes closely located to each other are also relatively more equidistantly located from their common TF and therefore subject to more similar levels of TF molecules. The absolute genomic distance of the coregulated genes to their common TF-coding gene tends to be less important in determining the degree of coexpression. Our results pinpoint the importance of taking into account the combined effect of distance and coregulation when studying prokaryotic coexpression and transcriptional regulation. PMID:28419102

Cerberus Plains: A most excellent Pathfinder landing site

NASA Technical Reports Server (NTRS)

Plescia, Jeff B.

1994-01-01

The Cerberus Plains in southeastern Elysium and western Amazonis cover greater than 10(exp 5) sq km, extending an east-west distance of approximately 3000 km and a north-south distance of up to 700 km near 195 deg. Crater numbers are 89 plus or minus 15 craters greater than 1 km/10(exp 6) sq km, indicating a stratigraphic age of Upper Amazonian and an absolute age of 200-500 Ma. The material forming the surface is referred to as the Cerberus Formation. The two ideas postulated about the unit's origin are fluvial and volcanic. Regardless of which interpretation is correct, the Cerberus Plains is an important candidate for a pathfinder landing site because it represents the youngest major geologic event (be it fluvial or volcanic) on Mars.

Kinematic measurement from panned cinematography.

PubMed

Gervais, P; Bedingfield, E W; Wronko, C; Kollias, I; Marchiori, G; Kuntz, J; Way, N; Kuiper, D

1989-06-01

Traditional 2-D cinematography has used a stationary camera with its optical axis perpendicular to the plane of motion. This method has constrained the size of the object plane or has introduced potential errors from a small subject image size with large object field widths. The purpose of this study was to assess a panning technique that could overcome the inherent limitations of small object field widths, small object image sizes and limited movement samples. The proposed technique used a series of reference targets in the object field that provided the necessary scales and origin translations. A 102 m object field was panned. Comparisons between criterion distances and film measured distances for field widths of 46 m and 22 m resulted in absolute mean differences that were comparable to that of the traditional method.

ORBITAL SOLUTIONS AND ABSOLUTE ELEMENTS OF THE ECLIPSING BINARY EE AQUARII

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wronka, Marissa Diehl; Gold, Caitlin; Sowell, James R.

2010-04-15

EE Aqr is a 7.9 mag Algol variable with a 12 hr orbital period. The Wilson-Devinney program is used to simultaneously solve 11 previously published light curves together with two existing radial velocity curves. The resulting masses are M {sub 1} = 2.24 {+-} 0.13 M {sub sun} and M {sub 2} = 0.72 {+-} 0.04 M {sub sun}, and the radii are R {sub 1} = 1.76 {+-} 0.03 R {sub sun} and R {sub 2} = 1.10 {+-} 0.02 R {sub sun}. The system has the lower-mass component completely filling its Roche lobe. Its distance from Hipparcos observationsmore » is 112 {+-} 10 pc. An improved ephemeris is derived, and no deviations in the period over time were seen. Light and velocity curve parameters, orbital elements, and absolute dimensions are presented, plus a comparison is made with previous solutions.« less

Precision Distances with the Tip of the Red Giant Branch Method

NASA Astrophysics Data System (ADS)

Beaton, Rachael Lynn; Carnegie-Chicago Hubble Program Team

2018-01-01

The Carnegie-Chicago Hubble Program aims to construct a distance ladder that utilizes old stellar populations in the outskirts of galaxies to produce a high precision measurement of the Hubble Constant that is independent of Cepheids. The CCHP uses the tip of the red giant branch (TRGB) method, which is a statistical measurement technique that utilizes the termination of the red giant branch. Two innovations combine to make the TRGB a competitive route to the Hubble Constant (i) the large-scale measurement of trigonometric parallax by the Gaia mission and (ii) the development of both precise and accurate means of determining the TRGB in both nearby (~1 Mpc) and distant (~20 Mpc) galaxies. Here I will summarize our progress in developing these standardized techniques, focusing on both our edge-detection algorithm and our field selection strategy. Using these methods, the CCHP has determined equally precise (~2%) distances to galaxies in the Local Group (< 1 Mpc) and across the Local Volume (< 20 Mpc). The TRGB is, thus, an incredibly powerful and straightforward means to determine distances to galaxies of any Hubble Type and, thus, has enormous potential for putting any number of astrophyiscal phenomena on absolute units.

The accuracy of the plusoptiX for measuring pupillary distance.

PubMed

Singman, Eric; Matta, Noelle; Tian, Jing; Silbert, David

2014-03-01

The plusoptiX photoscreener provides a number of measurements, including an estimate of inter-pupillary distance. We compare the plusoptiX photoscreening measurements of pupillary distance to that of an experienced optician in order to measure the accuracy of this reading. A retrospective chart review was done on 731 patients ranging in age from 1 to 16 years. Of these, 256 patients had both a plusoptiX photoscreening and a pupillary distance measurement by one of our office opticians. Of the 236 patients evaluated, 142 were orthophoric, 97 were esotropic, and 17 were exotropic. The mean absolute difference for the entire group between the two measurements was 0.3 mm. For the orthophoric patients, this metric was 0.3 mm, while for the esotropic patients it was 0.8 mm. There were too few exotropic patients to obtain reliable statistics. Although the average difference between the optician's measurements and those provided by the plusoptiX was within 0.5 mm for orthophoric patients, the variability of the measurements provided by the plusoptiX was too great to permit us to recommend the device as an alternative to the optician for routinely dispensing spectacles.

The movement characteristics of English Premiership rugby union players.

PubMed

Cahill, Nicola; Lamb, Kevin; Worsfold, Paul; Headey, Roy; Murray, Stafford

2013-01-01

The purpose of this investigation was to quantify the movement characteristics of elite rugby union players during competitive play and identify whether position-related differences exist. Ninety-eight elite players from eight English Premiership Clubs were tracked using global positioning systems (GPS) during 44 competitive matches throughout the 2010/2011 season. Player positions were defined as: (1) backs or forwards; (2) front, second and back rows, scrum half, inside and outside backs; (3) 15 individual positions (numbers 1-15). Analysis revealed the game is predominantly played at low speeds with little distance covered 'sprinting' by either the backs (50 ± 76 m) or the forwards (37 ± 64 m). The backs travelled greater (P < 0.05) absolute and relative distances than the forwards. The scrum half covered the greatest total distance during a match (7098 ± 778 m) and the front row the least (5158 ± 200 m). The back row covered the greatest distances at 'sprinting' speeds, particularly the number 8 position (77 m). These findings reflect notable differences in the movement characteristics displayed by elite rugby union players in specific positional roles, and reinforce the contemporary view that training programmes for such players ought to be structured with this in mind.

The use of the color Doppler ultrasonography in the diagnosis and monitoring of an atypical case of giant-cell arteritis.

PubMed

Martins, N; Polido-Pereira, J; Rodrigues, A M; Soares, F; Batista, P; Pereira da Silva, J A

2016-01-01

Giant Cell Arteritis (GCA) is a large vessels vasculitis that is typically characterised by headache, scalp tenderness, jaw claudication and visual disturbances. Temporal arteries color Doppler ultrasonography (CDUS) is a sensitive and non-invasive image technique used in the diagnosis of this disease. This work highlights the importance of CDUS in the diagnostic workup of GCA and also demonstrates it´s usefullness in the evaluation and documentation of the response to corticosteroids therapy in an atypical case of ACG.

Digital evaluation of absolute marginal discrepancy: A comparison of ceramic crowns fabricated with conventional and digital techniques.

PubMed

Liang, Shanshan; Yuan, Fusong; Luo, Xu; Yu, Zhuoren; Tang, Zhihui

2018-04-05

Marginal discrepancy is key to evaluating the accuracy of fixed dental prostheses. An improved method of evaluating marginal discrepancy is needed. The purpose of this in vitro study was to evaluate the absolute marginal discrepancy of ceramic crowns fabricated using conventional and digital methods with a digital method for the quantitative evaluation of absolute marginal discrepancy. The novel method was based on 3-dimensional scanning, iterative closest point registration techniques, and reverse engineering theory. Six standard tooth preparations for the right maxillary central incisor, right maxillary second premolar, right maxillary second molar, left mandibular lateral incisor, left mandibular first premolar, and left mandibular first molar were selected. Ten conventional ceramic crowns and 10 CEREC crowns were fabricated for each tooth preparation. A dental cast scanner was used to obtain 3-dimensional data of the preparations and ceramic crowns, and the data were compared with the "virtual seating" iterative closest point technique. Reverse engineering software used edge sharpening and other functional modules to extract the margins of the preparations and crowns. Finally, quantitative evaluation of the absolute marginal discrepancy of the ceramic crowns was obtained from the 2-dimensional cross-sectional straight-line distance between points on the margin of the ceramic crowns and the standard preparations based on the circumferential function module along the long axis. The absolute marginal discrepancy of the ceramic crowns fabricated using conventional methods was 115 ±15.2 μm, and 110 ±14.3 μm for those fabricated using the digital technique was. ANOVA showed no statistical difference between the 2 methods or among ceramic crowns for different teeth (P>.05). The digital quantitative evaluation method for the absolute marginal discrepancy of ceramic crowns was established. The evaluations determined that the absolute marginal discrepancies were within a clinically acceptable range. This method is acceptable for the digital evaluation of the accuracy of complete crowns. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Effects of repetitive or intensified instructions in telephone assisted, bystander cardiopulmonary resuscitation: an investigator-blinded, 4-armed, randomized, factorial simulation trial.

PubMed

van Tulder, R; Roth, D; Krammel, M; Laggner, R; Heidinger, B; Kienbacher, C; Novosad, H; Chwojka, C; Havel, C; Sterz, F; Schreiber, W; Herkner, H

2014-01-01

Compression depth is frequently suboptimal in cardiopulmonary resuscitation (CPR). We investigated effects of intensified wording and/or repetitive target depth instructions on compression depth in telephone-assisted, protocol driven, bystander CPR on a simulation manikin. Thirty-two volunteers performed 10 min of compression only-CPR in a prospective, investigator-blinded, 4-armed, factorial setting. Participants were randomized either to standard wording ("push down firmly 5 cm"), intensified wording ("it is very important to push down 5 cm every time") or standard or intensified wording repeated every 20s. Three dispatchers were randomized to give these instructions. Primary outcome was relative compression depth (absolute compression depth minus leaning depth). Secondary outcomes were absolute distance, hands-off times as well as BORG-scale and nine-hole peg test (NHPT), pulse rate and blood pressure to reflect physical exertion. We applied a random effects linear regression model. Relative compression depth was 35 ± 10 mm (standard) versus 31 ± 11 mm (intensified wording) versus 25 ± 8 mm (repeated standard) and 31 ± 14 mm (repeated intensified wording). Adjusted for design, body mass index and female sex, intensified wording and repetition led to decreased compression depth of 13 (95%CI -25 to -1) mm (p=0.04) and 9 (95%CI -21 to 3) mm (p=0.13), respectively. Secondary outcomes regarding intensified wording showed significant differences for absolute distance (43 ± 2 versus 20 (95%CI 3-37) mm; p=0.01) and hands-off times (60 ± 40 versus 157 (95%CI 63-251) s; p=0.04). In protocol driven, telephone-assisted, bystander CPR, intensified wording and/or repetitive target depth instruction will not improve compression depth compared to the standard instruction. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

DISTANCE AND KINEMATICS OF THE RED HYPERGIANT VY CMa: VERY LONG BASELINE ARRAY AND VERY LARGE ARRAY ASTROMETRY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, B.; Reid, M. J.; Menten, K. M.

2012-01-01

We report astrometric results of phase-referencing very long baseline interferometry observations of 43 GHz SiO maser emission toward the red hypergiant VY Canis Majoris (VY CMa) using the Very Long Baseline Array (VLBA). We measured a trigonometric parallax of 0.83 {+-} 0.08 mas, corresponding to a distance of 1.20{sup +0.13}{sub -0.10} kpc. Compared to previous studies, the spatial distribution of SiO masers has changed dramatically, while its total extent remains similar. The internal motions of the maser spots are up to 1.4 mas yr{sup -1}, corresponding to 8 km s{sup -1}, and show a tendency for expansion. After modeling themore » expansion of maser spots, we derived an absolute proper motion for the central star of {mu}{sub x} = -2.8 {+-} 0.2 and {mu}{sub y} = 2.6 {+-} 0.2 mas yr{sup -1} eastward and northward, respectively. Based on the maser distribution from the VLBA observations, and the relative position between the radio photosphere and the SiO maser emission at 43 GHz from the complementary Very Large Array observations, we estimate the absolute position of VY CMa at mean epoch 2006.53 to be {alpha}{sub J2000} = 07{sup h}22{sup m}58.{sup s}3259 {+-} 0.{sup s}0007, {delta}{sub J2000} = -25 Degree-Sign 46'03.''063 {+-} 0.''010. The position and proper motion of VY CMa from the VLBA observations differ significantly with values measured by the Hipparcos satellite. These discrepancies are most likely associated with inhomogeneities and dust scattering the optical light in the circumstellar envelope. The absolute proper motion measured with VLBA suggests that VY CMa may be drifting out of the giant molecular cloud to the east of it.« less

An integrated method for atherosclerotic carotid plaque segmentation in ultrasound image.

PubMed

Qian, Chunjun; Yang, Xiaoping

2018-01-01

Carotid artery atherosclerosis is an important cause of stroke. Ultrasound imaging has been widely used in the diagnosis of atherosclerosis. Therefore, segmenting atherosclerotic carotid plaque in ultrasound image is an important task. Accurate plaque segmentation is helpful for the measurement of carotid plaque burden. In this paper, we propose and evaluate a novel learning-based integrated framework for plaque segmentation. In our study, four different classification algorithms, along with the auto-context iterative algorithm, were employed to effectively integrate features from ultrasound images and later also the iteratively estimated and refined probability maps together for pixel-wise classification. The four classification algorithms were support vector machine with linear kernel, support vector machine with radial basis function kernel, AdaBoost and random forest. The plaque segmentation was implemented in the generated probability map. The performance of the four different learning-based plaque segmentation methods was tested on 29 B-mode ultrasound images. The evaluation indices for our proposed methods were consisted of sensitivity, specificity, Dice similarity coefficient, overlap index, error of area, absolute error of area, point-to-point distance, and Hausdorff point-to-point distance, along with the area under the ROC curve. The segmentation method integrated the random forest and an auto-context model obtained the best results (sensitivity 80.4 ± 8.4%, specificity 96.5 ± 2.0%, Dice similarity coefficient 81.0 ± 4.1%, overlap index 68.3 ± 5.8%, error of area -1.02 ± 18.3%, absolute error of area 14.7 ± 10.9%, point-to-point distance 0.34 ± 0.10 mm, Hausdorff point-to-point distance 1.75 ± 1.02 mm, and area under the ROC curve 0.897), which were almost the best, compared with that from the existed methods. Our proposed learning-based integrated framework investigated in this study could be useful for atherosclerotic carotid plaque segmentation, which will be helpful for the measurement of carotid plaque burden. Copyright © 2017 Elsevier B.V. All rights reserved.

Reference values for fatigued versus non-fatigued limb symmetry index measured by a newly designed single-leg hop test battery in healthy subjects: a pilot study.

PubMed

Leister, Iris; Mattiassich, Georg; Kindermann, Harald; Ortmaier, Reinhold; Barthofer, Jürgen; Vasvary, Imre; Katzensteiner, Klaus; Stelzhammer, Christine; Kulnik, Stefan Tino

2018-01-01

There is sparse evidence for return to sport criteria after knee injury. Functional performance deficits, particularly in fatigued muscular condition, should be verified prior to the attempt to return to high-risk pivoting sports. The purpose of this study was to generate reference values for the limb symmetry index (LSI) of healthy subjects in fatigued and non-fatigued muscular condition in a newly designed test battery. Forty-two healthy subjects [22 females, 20 males; mean (SD) age 30.4 (6.6) years] were evaluated using a test battery consisting of an isometric strength test, a series of five single-leg hop tests and an integrated fatigue protocol. Subjective physical activity was assessed with the Tegner Activity Scale (TAS). The cut-off values for healthy subjects were calculated considering the fifth percentile as the minimum reference value for the LSI and single-leg hop distance. The mean (SD) overall LSI was 98.8% (4.6). No significant gender or age specific differences in limb symmetry were observed. The comparison of the non-fatigued LSI with the overall LSI revealed no clinically relevant change due to muscular fatigue. Repeated measures ANOVA revealed a significant within effect on fatigue/non-fatigue condition ( F (1,38)  = 18.000; p  < 0.001, η 2  = 0.321) on absolute single-leg hop distance. Moreover, a significant between effect on the TAS-parameter ( F (1,38)  = 5.928; p  = 0.020, η 2  = 0.135 between: TAS ≤ 5/TAS > 5) and on gender ( F (1,38)  = 23.956; p  < 0.001, η 2  = 0.387) could be detected. The absolute jumping distance in the single-leg hop for distance was significantly reduced due to fatigue. No clinically relevant effect of muscular fatigue was observed on limb symmetry in our study sample. Gender and physical activity are important factors to be considered when interpreting reference values.

Rodent middens reveal episodic, long-distance plant colonizations across the hyperarid Atacama Desert over the last 34,000 years

USGS Publications Warehouse

Diaz, Francisca P.; Latorre, Claudio; Maldonado, Antonio; Quade, Jay; Betancourt, Julio L.

2012-01-01

Aim To document the impact of late Quaternary pluvial events on plant movements between the coast and the Andes across the Atacama Desert, northern Chile. Location Sites are located along the lower and upper fringes of absolute desert (1100–2800 m a.s.l.), between the western slope of the Andes and the Coastal Ranges of northern Chile (24–26° S). Methods We collected and individually radiocarbon dated 21 rodent middens. Plant macrofossils (fruits, seeds, flowers and leaves) were identified and pollen content analysed. Midden assemblages afford brief snapshots of local plant communities that existed within the rodents' limited foraging range during the several years to decades that it took the midden to accumulate. These assemblages were then compared with modern floras to determine the presence of extralocal species and species provenance. Results Five middens span the last glacial period (34–21 ka) and three middens are from the last glacial–interglacial transition (19–11 ka). The remaining 13 middens span the last 7000 years. Coastal hyperarid sites exhibit low taxonomic richness in middens at 19.3, 1.1, 1.0, 0.9, 0.5 ka and a modern sample. Middens are also dominated by the same plants that occur today. In contrast, middens dated to 28.1, 21.3, 17.3, 3.7 and 0.5 ka contain more species, including Andean extralocals. Precordillera middens (c. 2700 m) show a prominent increase in plant macrofossil richness, along with the appearance of Andean extralocals and sedges at 34.5 and 18.9 ka. Six younger middens dated to 6.1–0.1 ka are similar to the modern local vegetation. Main conclusions Increased species richness and Andean extralocal plants occurred along the current lower fringes of absolute desert during the last glacial–interglacial transition and late Holocene. The absence of soil carbonates indicates the persistence of absolute desert throughout the Quaternary. Colonization by Andean plants could have been accomplished through long-distance seed dispersal either by animals or floods that originated in the Andes. We postulate that dispersal would have been most frequent during regional pluvial events and associated increases in groundwater levels, forming local wetlands in the absolute desert, and generating large floods capable of crossing the Central Depression.

Absolute Calibration of the AXAF Telescope Effective Area

NASA Technical Reports Server (NTRS)

Kellogg, E.; Cohen, L.; Edgar, R.; Evans, I.; Freeman, M.; Gaetz, T.; Jerius, D.; McDermott, W. C.; McKinnon, P.; Murray, S.;

Effect of distance-related heterogeneity on population size estimates from point counts

USGS Publications Warehouse

Efford, Murray G.; Dawson, Deanna K.

2009-01-01

Point counts are used widely to index bird populations. Variation in the proportion of birds counted is a known source of error, and for robust inference it has been advocated that counts be converted to estimates of absolute population size. We used simulation to assess nine methods for the conduct and analysis of point counts when the data included distance-related heterogeneity of individual detection probability. Distance from the observer is a ubiquitous source of heterogeneity, because nearby birds are more easily detected than distant ones. Several recent methods (dependent double-observer, time of first detection, time of detection, independent multiple-observer, and repeated counts) do not account for distance-related heterogeneity, at least in their simpler forms. We assessed bias in estimates of population size by simulating counts with fixed radius w over four time intervals (occasions). Detection probability per occasion was modeled as a half-normal function of distance with scale parameter sigma and intercept g(0) = 1.0. Bias varied with sigma/w; values of sigma inferred from published studies were often 50% for a 100-m fixed-radius count. More critically, the bias of adjusted counts sometimes varied more than that of unadjusted counts, and inference from adjusted counts would be less robust. The problem was not solved by using mixture models or including distance as a covariate. Conventional distance sampling performed well in simulations, but its assumptions are difficult to meet in the field. We conclude that no existing method allows effective estimation of population size from point counts.

"Dip-and-read" paper-based analytical devices using distance-based detection with color screening.

PubMed

Yamada, Kentaro; Citterio, Daniel; Henry, Charles S

2018-05-15

An improved paper-based analytical device (PAD) using color screening to enhance device performance is described. Current detection methods for PADs relying on the distance-based signalling motif can be slow due to the assay time being limited by capillary flow rates that wick fluid through the detection zone. For traditional distance-based detection motifs, analysis can take up to 45 min for a channel length of 5 cm. By using a color screening method, quantification with a distance-based PAD can be achieved in minutes through a "dip-and-read" approach. A colorimetric indicator line deposited onto a paper substrate using inkjet-printing undergoes a concentration-dependent colorimetric response for a given analyte. This color intensity-based response has been converted to a distance-based signal by overlaying a color filter with a continuous color intensity gradient matching the color of the developed indicator line. As a proof-of-concept, Ni quantification in welding fume was performed as a model assay. The results of multiple independent user testing gave mean absolute percentage error and average relative standard deviations of 10.5% and 11.2% respectively, which were an improvement over analysis based on simple visual color comparison with a read guide (12.2%, 14.9%). In addition to the analytical performance comparison, an interference study and a shelf life investigation were performed to further demonstrate practical utility. The developed system demonstrates an alternative detection approach for distance-based PADs enabling fast (∼10 min), quantitative, and straightforward assays.

Research in Algebraic Manipulation.

DTIC Science & Technology

1980-01-01

that are taken from mathematics are presented in chapter V. Those who are familiar with the results of valuation theory can skip this chapter...be an integer, and assume 3" divides a but 3’ + i does not. We can write a as 3 ’p. The the 3-adic valuation of a is 11aJ13 = 113pllb = 3’. When p = 0...primes. In general these distance measures are called p-adic valuations . In elementary analysis and topology, absolute values are used to define

Velocity precision measurements using laser Doppler anemometry

NASA Astrophysics Data System (ADS)

Dopheide, D.; Taux, G.; Narjes, L.

1985-07-01

A Laser Doppler Anemometer (LDA) was calibrated to determine its applicability to high pressure measurements (up to 10 bars) for industrial purposes. The measurement procedure with LDA and the experimental computerized layouts are presented. The calibration procedure is based on absolute accuracy of Doppler frequency and calibration of interference strip intervals. A four-quadrant detector allows comparison of the interference strip distance measurements and computer profiles. Further development of LDA is recommended to increase accuracy (0.1% inaccuracy) and to apply the method industrially.

Wireless passive radiation sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pfeifer, Kent B; Rumpf, Arthur N; Yelton, William G

2013-12-03

A novel measurement technique is employed using surface acoustic wave (SAW) devices, passive RF, and radiation-sensitive films to provide a wireless passive radiation sensor that requires no batteries, outside wiring, or regular maintenance. The sensor is small (<1 cm.sup.2), physically robust, and will operate unattended for decades. In addition, the sensor can be insensitive to measurement position and read distance due to a novel self-referencing technique eliminating the need to measure absolute responses that are dependent on RF transmitter location and power.

Ophthalmic presentation of giant cell arteritis in African-Americans

PubMed Central

Garrity, S T; Pistilli, M; Vaphiades, M S; Richards, N Q; Subramanian, P S; Rosa, P R; Lam, B L; Osborne, B J; Liu, G T; Duncan, K E; Shin, R K; Volpe, N J; Shindler, K S; Lee, M S; Moster, M L; Tracey, E H; Cuprill-Nilson, S E; Tamhankar, M A

2017-01-01

Purpose To determine the differences in the presentation of ophthalmic giant cell arteritis between African-Americans and Caucasians. Methods This was a multicenter retrospective case series comparing African-American patients with ophthalmic GCA to a previously published Caucasian cohort. Neuro-ophthalmic centers across the United States were contacted to provide data on African-American patients with biopsy-proven ophthalmic giant cell arteritis. The differences between African-American and Caucasian patients with respect to multiple variables, including age, sex, systemic and ophthalmic signs and symptoms, ocular ischemic lesions, and laboratory results were studied. Results The Caucasian cohort was slightly older (mean=76.1 years) than the African-American cohort (mean=72.6 years, P=0.03), and there was no difference in sex distribution between the two cohorts. Headache, neck pain, and anemia were more frequent, while jaw claudication was less frequent in African-Americans (P<0.01, <0.001, 0.02, and 0.03 respectively). Acute vision loss was the most common presentation of giant cell arteritis in both groups, though it was less common in African-Americans (78 vs 98% of Caucasians, P<0.001). Eye pain was more common in African-Americans (28 vs 8% of Caucasians, P<0.01). Conclusions The presenting features of ophthalmic giant cell arteritis in African-Americans and Caucasians are not markedly different, although a few significant differences exist, including higher rates of headache, neck pain, anemia, and eye pain, and lower rates of jaw claudication and acute vision loss in African-Americans. Persons presenting with suspicious signs and symptoms should undergo evaluation for giant cell arteritis regardless of race. PMID:27636230

Primary Self-EXPANDing Nitinol Stenting vs Balloon Angioplasty With Optional Bailout Stenting for the Treatment of Infrapopliteal Artery Disease in Patients With Severe Intermittent Claudication or Critical Limb Ischemia (EXPAND Study).

PubMed

Schulte, Karl-Ludwig; Pilger, Ernst; Schellong, Sebastian; Tan, Kong Ten; Baumann, Frederic; Langhoff, Ralf; Torsello, Giovanni; Zeller, Thomas; Amendt, Klaus; Brodmann, Marianne

2015-10-01

To compare primary placement of a self-expanding nitinol stent to percutaneous transluminal angioplasty (PTA) with bailout stenting in infrapopliteal arteries of patients with severe intermittent claudication or critical limb ischemia (CLI). In the EXPAND trial (ClinicalTrials.gov; identifier NCT00906022), 92 patients (mean age 72.9±9.5 years; 62 men) undergoing treatment for infrapopliteal stenosis in 11 European centers were randomized 1:1 to either self-expanding nitinol stenting with the Astron Pulsar/Pulsar-18 nitinol stent or PTA with bailout stenting. The primary endpoint was sustainable clinical improvement after 12 months, defined as a ≥1-category increase for Rutherford category 3 patients or a ≥2-category increase for CLI patients (Rutherford categories 4/5) compared with baseline. Furthermore, target lesion revascularization (TLR), mortality, and amputation were assessed after 12 months. Sustained clinical improvement at 1 year was observed in 74.3% of the patients treated with primary stenting and in 68.6% of the patients treated with PTA and bailout stenting (p>0.05). Kaplan-Meier estimates of freedom from TLR (76.6% and 77.6%), mortality (7.4% vs 2.1%), and amputation [8.9% (major 6.7%) vs 13.2% (major 8.7%)] at 1 year were not significantly different. Primary self-expanding nitinol stenting did not show statistically different clinical outcomes compared to angioplasty with bailout stenting for infrapopliteal lesions. © The Author(s) 2015.

Exercise performance and peripheral vascular insufficiency improve with AMPK activation in high-fat diet-fed mice.

PubMed

Baltgalvis, Kristen A; White, Kathy; Li, Wei; Claypool, Mark D; Lang, Wayne; Alcantara, Raniel; Singh, Baljit K; Friera, Annabelle M; McLaughlin, John; Hansen, Derek; McCaughey, Kelly; Nguyen, Henry; Smith, Ira J; Godinez, Guillermo; Shaw, Simon J; Goff, Dane; Singh, Rajinder; Markovtsov, Vadim; Sun, Tian-Qiang; Jenkins, Yonchu; Uy, Gerald; Li, Yingwu; Pan, Alison; Gururaja, Tarikere; Lau, David; Park, Gary; Hitoshi, Yasumichi; Payan, Donald G; Kinsella, Todd M

2014-04-15

Intermittent claudication is a form of exercise intolerance characterized by muscle pain during walking in patients with peripheral artery disease (PAD). Endothelial cell and muscle dysfunction are thought to be important contributors to the etiology of this disease, but a lack of preclinical models that incorporate these elements and measure exercise performance as a primary end point has slowed progress in finding new treatment options for these patients. We sought to develop an animal model of peripheral vascular insufficiency in which microvascular dysfunction and exercise intolerance were defining features. We further set out to determine if pharmacological activation of 5'-AMP-activated protein kinase (AMPK) might counteract any of these functional deficits. Mice aged on a high-fat diet demonstrate many functional and molecular characteristics of PAD, including the sequential development of peripheral vascular insufficiency, increased muscle fatigability, and progressive exercise intolerance. These changes occur gradually and are associated with alterations in nitric oxide bioavailability. Treatment of animals with an AMPK activator, R118, increased voluntary wheel running activity, decreased muscle fatigability, and prevented the progressive decrease in treadmill exercise capacity. These functional performance benefits were accompanied by improved mitochondrial function, the normalization of perfusion in exercising muscle, increased nitric oxide bioavailability, and decreased circulating levels of the endogenous endothelial nitric oxide synthase inhibitor asymmetric dimethylarginine. These data suggest that aged, obese mice represent a novel model for studying exercise intolerance associated with peripheral vascular insufficiency, and pharmacological activation of AMPK may be a suitable treatment for intermittent claudication associated with PAD.

Hemorrhagic lumbar facet cysts accompanying a spinal subdural hematoma at the same level

PubMed Central

Ikeda, Osamu; Minami, Norihiko; Yamazaki, Masashi; Koda, Masao; Morinaga, Tatsuo

2015-01-01

Context We present a rare and interesting case of hemorrhagic lumbar facet cysts accompanying a spinal subdural hematoma at the same level suggesting a possible mechanism by which spinal subdural hematomas can arise. Findings A 71-year-old man presented with persistent sciatic pain and intermittent claudication. Magnetic resonance imaging demonstrated a multilocular mass lesion that showed high signal intensity in both T1- and T2-weighted images, and was located both inside and outside of the spinal canal. Computed tomographic myelography showed a cap-shaped block of the dural tube at L5 and computed tomography with L5–S facet arthrography demonstrated cystic masses. The patient was diagnosed with lumbar radiculopathy caused by hemorrhagic facet cysts, and then progressed to surgical treatment. Surgery revealed that the cysts contained blood clots, and intraoperative findings that the inside of the dural tube appeared blackish and that the dural tube was tensely ballooned after removal of the cysts led us to explorative durotomy. The durotomy demonstrated concentrated old blood pooling both in the dorsal and ventral subdural space, and these spaces were subsequently drained. After surgery, his sciatic pain and intermittent claudication resolved. There was no evidence of cyst mass recurrence at 2 years of follow-up. Conclusion We propose a newly described mechanism for the formation of spinal subdural hematomas. We recommend surgeons be alert to epidural lesions causing repeated acute compression of the dural tube, which can cause spinal subdural hematoma, and consider the possible coexistence of these lesions in diagnosis and strategic surgical decisions. PMID:24976137

Hemorrhagic lumbar facet cysts accompanying a spinal subdural hematoma at the same level.

PubMed

Ikeda, Osamu; Minami, Norihiko; Yamazaki, Masashi; Koda, Masao; Morinaga, Tatsuo

2015-03-01

We present a rare and interesting case of hemorrhagic lumbar facet cysts accompanying a spinal subdural hematoma at the same level suggesting a possible mechanism by which spinal subdural hematomas can arise. A 71-year-old man presented with persistent sciatic pain and intermittent claudication. Magnetic resonance imaging demonstrated a multilocular mass lesion that showed high signal intensity in both T1- and T2-weighted images, and was located both inside and outside of the spinal canal. Computed tomographic myelography showed a cap-shaped block of the dural tube at L5 and computed tomography with L5-S facet arthrography demonstrated cystic masses. The patient was diagnosed with lumbar radiculopathy caused by hemorrhagic facet cysts, and then progressed to surgical treatment. Surgery revealed that the cysts contained blood clots, and intraoperative findings that the inside of the dural tube appeared blackish and that the dural tube was tensely ballooned after removal of the cysts led us to explorative durotomy. The durotomy demonstrated concentrated old blood pooling both in the dorsal and ventral subdural space, and these spaces were subsequently drained. After surgery, his sciatic pain and intermittent claudication resolved. There was no evidence of cyst mass recurrence at 2 years of follow-up. We propose a newly described mechanism for the formation of spinal subdural hematomas. We recommend surgeons be alert to epidural lesions causing repeated acute compression of the dural tube, which can cause spinal subdural hematoma, and consider the possible coexistence of these lesions in diagnosis and strategic surgical decisions.

Relationship between central and peripheral atherosclerosis and left ventricular dysfunction in a community population.

PubMed

Tsao, Connie W; Gona, Philimon; Salton, Carol; Murabito, Joanne M; Oyama, Noriko; Danias, Peter G; O'Donnell, Christopher J; Manning, Warren J; Yeon, Susan B

2011-08-01

We aimed to determine the relationships between resting left ventricular (LV) wall motion abnormalities (WMAs), aortic plaque, and peripheral artery disease (PAD) in a community cohort. A total of 1726 Framingham Heart Study Offspring Cohort participants (806 males, 65 ± 9 years) underwent cardiovascular magnetic resonance with quantification of aortic plaque volume and assessment of regional left ventricular systolic function. Claudication, lower extremity revascularization, and ankle-brachial index (ABI) were recorded at the most contemporaneous examination visit. WMAs were associated with greater aortic plaque burden, decreased ABI, and claudication in age- and sex-adjusted analyses (all p < 0.001), which were not significant after adjustment for cardiovascular risk factors. In age- and sex-adjusted analyses, both the presence (p < 0.001) and volume of aortic plaque were associated with decreased ABI (p < 0.001). After multivariable adjustment, an ABI ≤ 0.9 or prior revascularization was associated with a threefold odds of aortic plaque (p = 0.0083). Plaque volume significantly increased with decreasing ABI in multivariable-adjusted analyses (p < 0.0001). In this free-living population, associations of WMAs with aortic plaque burden and clinical measures of PAD were attenuated after adjustment for coronary heart disease risk factors. Aortic plaque volume and ABI remained strongly negatively correlated after multivariable adjustment. Our findings suggest that the association between coronary heart disease and non-coronary atherosclerosis is explained by cardiovascular risk factors. Aortic atherosclerosis and PAD remain strongly associated after multivariable adjustment, suggesting shared mechanisms beyond those captured by traditional risk factors.

Five-year durability of stand-alone interspinous process decompression for lumbar spinal stenosis

PubMed Central

Nunley, Pierce D; Patel, Vikas V; Orndorff, Douglas G; Lavelle, William F; Block, Jon E; Geisler, Fred H

2017-01-01

Background Lumbar spinal stenosis is the most common indication for spine surgery in older adults. Interspinous process decompression (IPD) using a stand-alone spacer that functions as an extension blocker offers a minimally invasive treatment option for intermittent neurogenic claudication associated with spinal stenosis. Methods This study evaluated the 5-year clinical outcomes for IPD (Superion®) from a randomized controlled US Food and Drug Administration (FDA) noninferiority trial. Outcomes included Zurich Claudication Questionnaire (ZCQ) symptom severity (ss), physical function (pf), and patient satisfaction (ps) subdomains, leg and back pain visual analog scale (VAS), and Oswestry Disability Index (ODI). Results At 5 years, 84% of patients (74 of 88) demonstrated clinical success on at least two of three ZCQ domains. Individual ZCQ domain success rates were 75% (66 of 88), 81% (71 of 88), and 90% (79 of 88) for ZCQss, ZCQpf, and ZCQps, respectively. Leg and back pain success rates were 80% (68 of 85) and 65% (55 of 85), respectively, and the success rate for ODI was 65% (57 of 88). Percentage improvements over baseline were 42%, 39%, 75%, 66%, and 58% for ZCQss, ZCQpf, leg and back pain VAS, and ODI, respectively (all P<0.001). Within-group effect sizes were classified as very large for four of five clinical outcomes (ie, >1.0; all P<0.0001). Seventy-five percent of IPD patients were free from reoperation, revision, or supplemental fixation at their index level at 5 years. Conclusion After 5 years of follow-up, IPD with a stand-alone spacer provides sustained clinical benefit. PMID:28919727

Five-year durability of stand-alone interspinous process decompression for lumbar spinal stenosis.

PubMed

Nunley, Pierce D; Patel, Vikas V; Orndorff, Douglas G; Lavelle, William F; Block, Jon E; Geisler, Fred H

2017-01-01

Lumbar spinal stenosis is the most common indication for spine surgery in older adults. Interspinous process decompression (IPD) using a stand-alone spacer that functions as an extension blocker offers a minimally invasive treatment option for intermittent neurogenic claudication associated with spinal stenosis. This study evaluated the 5-year clinical outcomes for IPD (Superion ® ) from a randomized controlled US Food and Drug Administration (FDA) noninferiority trial. Outcomes included Zurich Claudication Questionnaire (ZCQ) symptom severity (ss), physical function (pf), and patient satisfaction (ps) subdomains, leg and back pain visual analog scale (VAS), and Oswestry Disability Index (ODI). At 5 years, 84% of patients (74 of 88) demonstrated clinical success on at least two of three ZCQ domains. Individual ZCQ domain success rates were 75% (66 of 88), 81% (71 of 88), and 90% (79 of 88) for ZCQss, ZCQpf, and ZCQps, respectively. Leg and back pain success rates were 80% (68 of 85) and 65% (55 of 85), respectively, and the success rate for ODI was 65% (57 of 88). Percentage improvements over baseline were 42%, 39%, 75%, 66%, and 58% for ZCQss, ZCQpf, leg and back pain VAS, and ODI, respectively (all P <0.001). Within-group effect sizes were classified as very large for four of five clinical outcomes (ie, >1.0; all P <0.0001). Seventy-five percent of IPD patients were free from reoperation, revision, or supplemental fixation at their index level at 5 years. After 5 years of follow-up, IPD with a stand-alone spacer provides sustained clinical benefit.

Stent-Graft Placement with Early Debridement and Antibiotic Treatment for Femoral Pseudoaneurysms in Intravenous Drug Addicts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, Qining, E-mail: cqmufqn@163.com; Meng, Xiyun, E-mail: 383274177@qq.com; Li, Fenghe, E-mail: lfh-cqmu@gmail.com

PurposeExplore the application of endovascular covered stent-graft (SG) placement in femoral pseudoaneurysms in intravenous drug addicts.Materials and MethodsWe evaluated a consecutive series of pseudoaneurysm in intravenous drug addicts treated with SGs from August 2010 to December 2013.Results15 patients with 16 arterial pseudoaneurysms were enrolled in this study. All were males with a mean age of 36.9 years. Hemorrhage was the most common reason (93.8 %) for seeking medical care, and 3 of these patients were in hemorrhagic shock at admission. All patients received broad-spectrum antibiotics, and debridement and drainage were implemented after SG placement. 7 of the 13 cases which had microbiologicmore » results showed mixed infections, while gram-negative bacteria were the major pathogens. Except for 2 patients, who were lost to follow-up, two new pseudoaneurysms formed due to delayed debridement, and one stent thrombosis occurred, none of the remaining cases had SG infection or developed claudication.ConclusionsSG placement controls massive hemorrhage rapidly, gives enough time for subsequent treatment for pseudoaneurysms due to intravenous drug abuse, and reduces the incidence of postoperative claudication. With appropriate broad-spectrum antibiotics and early debridement, the incidence of SG infection is relatively low. It is an effective alternative especially as temporary bridge measure for critical patients. However, the high cost, uncertain long-term prospects, high demand for medical adherence, and the risk of using the conduits for re-puncture call for a cautious selection of patients. More evidence is required for the application of this treatment.« less

Community walking programs for treatment of peripheral artery disease

PubMed Central

Mays, Ryan J.; Rogers, R. Kevin; Hiatt, William R.; Regensteiner, Judith G.

2013-01-01

Background Supervised walking programs offered at medical facilities for patients with peripheral artery disease (PAD) and intermittent claudication (IC), while effective, are often not utilized due to barriers including lack of reimbursement and the need to travel to specialized locations for the training intervention. Walking programs for PAD patients that occur in community settings, such as those outside of supervised settings, may be a viable treatment option, as they are convenient and potentially bypass the need for supervised walking. This review evaluated the various methodologies and outcomes of community walking programs for PAD. Methods A literature review using appropriate search terms was conducted within PubMed/Medline and the Cochrane databases to identify studies in the English language employing community walking programs to treat PAD patients with IC. Search results were reviewed, and relevant articles were identified that form the basis of this review. The primary outcome was peak walking performance on the treadmill. Results Randomized controlled trials (n=10) examining peak walking outcomes in 558 PAD patients demonstrated that supervised exercise programs were more effective than community walking studies that consisted of general recommendations for patients with IC to walk at home. Recent community trials that incorporated more advice and feedback for PAD patients in general resulted in similar outcomes with no differences in peak walking time compared to supervised walking exercise groups. Conclusions Unstructured recommendations for patients with symptomatic PAD to exercise in the community are not efficacious. Community walking programs with more feedback and monitoring offer improvements in walking performance for patients with claudication and may bypass some obstacles associated with facility-based exercise programs. PMID:24103409

The ClaudicatioNet concept: design of a national integrated care network providing active and healthy aging for patients with intermittent claudication

PubMed Central

Lauret, Gert-Jan; Gijsbers, Harm JH; Hendriks, Erik JM; Bartelink, Marie-Louise; de Bie, Rob A; Teijink, Joep AW

2012-01-01

Introduction: Intermittent claudication (IC) is a manifestation of peripheral arterial occlusive disease (PAOD). Besides cardiovascular risk management, supervised exercise therapy (SET) should be offered to all patients with IC. Outdated guidelines, an insufficient number of specialized physiotherapists (PTs), lack of awareness of the importance of SET by referring physicians, and misguided financial incentives all seriously impede the availability of a structured SET program in The Netherlands. Description of care practice: By initiating regional care networks, ClaudicatioNet aims to improve the quality of care for patients with IC. Based on the chronic care model as a conceptual framework, these networks should enhance the access, continuity, and (cost) efficiency of the health care system. With the aid of a national database, health care professionals will be able to benchmark patient results while ClaudicatioNet will be able to monitor quality of care by way of functional and patient reported outcome measures. Discussion: The success of ClaudicatioNet is dependent on several factors. Vascular surgeons, general practitioners and coordinating central caregivers will need to team up and work in close collaboration with specialized PTs. A substantial task in the upcoming years will be to monitor the quality, volume, and distribution of ClaudicatioNet PTs. Finally, misguided financial incentives within the Dutch health care system need to be tackled. Conclusion: With ClaudicatioNet, integrated care pathways are likely to improve in the upcoming years. This should result in the achievement of optimal quality of care for all patients with IC. PMID:22942648

Modified fenestration with restorative spinoplasty for lumbar spinal stenosis.

PubMed

Matsudaira, Ko; Yamazaki, Takashi; Seichi, Atsushi; Hoshi, Kazuto; Hara, Nobuhiro; Ogiwara, Satoshi; Terayama, Sei; Chikuda, Hirotaka; Takeshita, Katsushi; Nakamura, Kozo

2009-06-01

The authors developed an original procedure, modified fenestration with restorative spinoplasty (MFRS) for the treatment of lumbar spinal stenosis. The first step is to cut the spinous process in an L-shape, which is caudally reflected. This procedure allows easy access to the spinal canal, including lateral recesses, and makes it easy to perform a trumpet-style decompression of the nerve roots without violating the facet joints. After the decompression of neural tissues, the spinous process is anatomically restored (spinoplasty). The clinical outcomes at 2 years were evaluated using the Japanese Orthopaedic Association (JOA) scale and patients' satisfaction. Radiological follow-up included radiographs and CT. Between January 2000 and December 2002, 109 patients with neurogenic intermittent claudication with or without mild spondylolisthesis underwent MFRS. Of these, 101 were followed up for at least 2 years (follow-up rate 93%). The average score on the self-administered JOA scale in 89 patients without comorbidity causing gait disturbance improved from 13.3 preoperatively to 22.9 at 2 years' follow-up. Neurogenic intermittent claudication disappeared in all cases. The patients' assessment of treatment satisfaction was "satisfied" in 74 cases, "slightly satisfied" in 12, "slightly dissatisfied" in 2, and "dissatisfied" in 1 case. In 16 cases (18%), a minimum progression of slippage occurred, but no symptomatic instability or recurrent stenosis was observed. Computed tomography showed that the lateral part of the facet joints was well preserved, and the mean residual ratio was 80%. The MFRS technique produces an adequate and safe decompression of the spinal canal, even in patients with narrow and steep facet joints in whom conventional fenestration is technically demanding.

Report from a quality assurance program on patients undergoing the MILD procedure.

PubMed

Durkin, Brian; Romeiser, Jamie; Shroyer, A Laurie W; Schiller, Robin; Bae, Jin; Davis, Raphael P; Peyster, Robert; Benveniste, Helene

2013-05-01

To characterize trends in pain and functional outcomes and identify risk factors in patients with lumbar spinal stenosis (LSS) and neurogenic claudication undergoing the "Minimally Invasive Lumbar Decompression" (MILD) procedure. Retrospective observational cohort study. Academic multidisciplinary pain center at Stony Brook Medicine. Patients undergoing the MILD procedure from October 2010 to November 2012. De-identified perioperative, pain and function related data for 50 patients undergoing MILD were extracted from the Center for Pain Management's quality assessment database. Data included numerical rating scale (NRS), symptom severity and physical function (Zurich Claudication Questionnaire), functional status (Oswestry Disability Index [ODI]), pain interference scores (National Institutes of Health Patient-Reported Outcomes Measurement Information System [PROMIS]), and patients' self-reported low back and lower extremity pain distribution. No MILD patient incurred procedure-related complications. Average NRS scores decreased postoperatively and 64.3% of patients reported less pain at 3 months. Clinically meaningful functional ODI improvements of at least 20% from baseline were present in 25% of the patients at 6 months. Preliminary analysis of changes in PROMIS scores at 3 months revealed that pre-MILD "severe" lumbar canal stenosis may be associated with high risk of "no improvement." No such impact was observed for NRS or ODI outcomes. Overall, pain is reduced and functional status improved in LSS patients following the MILD procedure at 3 and 6 months. Given the small sample size, it is not yet possible to identify patient subgroups at risk for "no improvement." Continued follow-up of longer-term outcomes appears warranted to develop evidence-based patient selection criteria. Wiley Periodicals, Inc.

Computerized image analysis of cell-cell interactions in human renal tissue by using multi-channel immunoflourescent confocal microscopy

NASA Astrophysics Data System (ADS)

Peng, Yahui; Jiang, Yulei; Liarski, Vladimir M.; Kaverina, Natalya; Clark, Marcus R.; Giger, Maryellen L.

2012-03-01

Analysis of interactions between B and T cells in tubulointerstitial inflammation is important for understanding human lupus nephritis. We developed a computer technique to perform this analysis, and compared it with manual analysis. Multi-channel immunoflourescent-microscopy images were acquired from 207 regions of interest in 40 renal tissue sections of 19 patients diagnosed with lupus nephritis. Fresh-frozen renal tissue sections were stained with combinations of immunoflourescent antibodies to membrane proteins and counter-stained with a cell nuclear marker. Manual delineation of the antibodies was considered as the reference standard. We first segmented cell nuclei and cell membrane markers, and then determined corresponding cell types based on the distances between cell nuclei and specific cell-membrane marker combinations. Subsequently, the distribution of the shortest distance from T cell nuclei to B cell nuclei was obtained and used as a surrogate indicator of cell-cell interactions. The computer and manual analyses results were concordant. The average absolute difference was 1.1+/-1.2% between the computer and manual analysis results in the number of cell-cell distances of 3 μm or less as a percentage of the total number of cell-cell distances. Our computerized analysis of cell-cell distances could be used as a surrogate for quantifying cell-cell interactions as either an automated and quantitative analysis or for independent confirmation of manual analysis.

Spectral Properties and Variability of BIS objects

NASA Astrophysics Data System (ADS)

Gaudenzi, S.; Nesci, R.; Rossi, C.; Sclavi, S.; Gigoyan, K. S.; Mickaelian, A. M.

2017-10-01

Through the analysis and interpretation of newly obtained and of literature data we have clarified the nature of poorly investigated IRAS point sources classified as late type stars, belonging to the Byurakan IRAS Stars catalog. From medium resolution spectroscopy of 95 stars we have strongly revised 47 spectral types and newly classified 31 sources. Nine stars are of G or K types, four are N carbon stars in the Asymptotic Giant Branch, the others being M-type stars. From literature and new photometric observations we have studied their variability behaviour. For the regular variables we determined distances, absolute magnitudes and mass loss rates. For the other stars we estimated the distances, ranging between 1.3 and 10 kpc with a median of 2.8 kpc from the galactic plane, indicating that BIS stars mostly belong to the halo population.

Laser spectroscopy for totally non-intrusive detection of oxygen in modified atmosphere food packages

NASA Astrophysics Data System (ADS)

Cocola, L.; Fedel, M.; Poletto, L.; Tondello, G.

2015-04-01

A device for measuring the oxygen concentration inside packages in modified atmosphere working in a completely non-intrusive way has been developed and tested. The device uses tunable diode laser spectroscopy in a geometry similar to a short distance LIDAR: A laser beam is sent through the top film of a food package, and the absorption is measured by detecting the light scattered by the bottom of the container or by a portion of the food herein contained. The device can operate completely in a contactless way from the package, and the distances of absorption both outside and inside the package are measured with a triangulation system. The performances of the device have been tested for various types of containers, and absolute values for the oxygen concentration have been compared with standard albeit destructive measurements.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, J; Gu, X; Lu, W

Purpose: A novel distance-dose weighting method for label fusion was developed to increase segmentation accuracy in dosimetrically important regions for prostate radiation therapy. Methods: Label fusion as implemented in the original SIMPLE (OS) for multi-atlas segmentation relies iteratively on the majority vote to generate an estimated ground truth and DICE similarity measure to screen candidates. The proposed distance-dose weighting puts more values on dosimetrically important regions when calculating similarity measure. Specifically, we introduced distance-to-dose error (DDE), which converts distance to dosimetric importance, in performance evaluation. The DDE calculates an estimated DE error derived from surface distance differences between the candidatemore » and estimated ground truth label by multiplying a regression coefficient. To determine the coefficient at each simulation point on the rectum, we fitted DE error with respect to simulated voxel shift. The DEs were calculated by the multi-OAR geometry-dosimetry training model previously developed in our research group. Results: For both the OS and the distance-dose weighted SIMPLE (WS) results, the evaluation metrics for twenty patients were calculated using the ground truth segmentation. The mean difference of DICE, Hausdorff distance, and mean absolute distance (MAD) between OS and WS have shown 0, 0.10, and 0.11, respectively. In partial MAD of WS which calculates MAD within a certain PTV expansion voxel distance, the lower MADs were observed at the closer distances from 1 to 8 than those of OS. The DE results showed that the segmentation from WS produced more accurate results than OS. The mean DE error of V75, V70, V65, and V60 were decreased by 1.16%, 1.17%, 1.14%, and 1.12%, respectively. Conclusion: We have demonstrated that the method can increase the segmentation accuracy in rectum regions adjacent to PTV. As a result, segmentation using WS have shown improved dosimetric accuracy than OS. The WS will provide dosimetrically important label selection strategy in multi-atlas segmentation. CPRIT grant RP150485.« less

Overlapping communities detection based on spectral analysis of line graphs

NASA Astrophysics Data System (ADS)

Gui, Chun; Zhang, Ruisheng; Hu, Rongjing; Huang, Guoming; Wei, Jiaxuan

2018-05-01

Community in networks are often overlapping where one vertex belongs to several clusters. Meanwhile, many networks show hierarchical structure such that community is recursively grouped into hierarchical organization. In order to obtain overlapping communities from a global hierarchy of vertices, a new algorithm (named SAoLG) is proposed to build the hierarchical organization along with detecting the overlap of community structure. SAoLG applies the spectral analysis into line graphs to unify the overlap and hierarchical structure of the communities. In order to avoid the limitation of absolute distance such as Euclidean distance, SAoLG employs Angular distance to compute the similarity between vertices. Furthermore, we make a micro-improvement partition density to evaluate the quality of community structure and use it to obtain the more reasonable and sensible community numbers. The proposed SAoLG algorithm achieves a balance between overlap and hierarchy by applying spectral analysis to edge community detection. The experimental results on one standard network and six real-world networks show that the SAoLG algorithm achieves higher modularity and reasonable community number values than those generated by Ahn's algorithm, the classical CPM and GN ones.

Eight new Milky Way companions discovered in first-year Dark Energy Survey data

DOE PAGES

Bechtol, K.

2015-06-30

We report the discovery of eight new Milky Way companions inmore » $$\\sim 1800\\;{\\mathrm{deg}}^{2}$$ of optical imaging data collected during the first year of the Dark Energy Survey (DES). Each system is identified as a statistically significant over-density of individual stars consistent with the expected isochrone and luminosity function of an old and metal-poor stellar population. The objects span a wide range of absolute magnitudes (MV from $-2.2$ to $$-7.4\\;\\mathrm{mag}$$), physical sizes ($$10-170\\;\\mathrm{pc}$$), and heliocentric distances ($$30-330\\;\\mathrm{kpc}$$). Based on the low surface brightnesses, large physical sizes, and/or large Galactocentric distances of these objects, several are likely to be new ultra-faint satellite galaxies of the Milky Way and/or Magellanic Clouds. We introduce a likelihood-based algorithm to search for and characterize stellar over-densities, as well as identify stars with high satellite membership probabilities. As a result, we also present completeness estimates for detecting ultra-faint galaxies of varying luminosities, sizes, and heliocentric distances in the first-year DES data.« less

Study of a New CPM Pair 2Mass 14515781-1619034

NASA Astrophysics Data System (ADS)

Falcon, Israel Tejera

2013-04-01

In this paper I present the results of a study of 2Mass 14515781-1619034 as components of a common proper motion pair. Because PPMXL catalog's proper motion data not provide any information about secondary star, I deduced it independently, obtaining similar proper motions for both components. Halbwalchs' criteria indicates that this is a CPM ystem. The criterion of Francisco Rica, which is based on the compatibility of the kinematic function of the equatorial coordinates, indicates that this pair has a 99% probability of being a physical one (Rica, 2007). Also other important criteria (Dommanget, 1956, Peter Van De Kamp, 1961, Sinachopoulus, 1992, Close, 2003), indicate a physical system. With the absolute visual magnitude of both components, I obtained distance modulus 7.29 and 7.59, which put the components of the system at a distance of 287.1 and 329.6 parsecs. Taking into account errors in determining the magnitudes, this means that the probability that both components are situated at the same distance is 96%. I suggest that this pair be included in the WDS catalog.

Absolute and convective instabilities of a film flow down a vertical fiber subjected to a radial electric field

NASA Astrophysics Data System (ADS)

Liu, Rong; Chen, Xue; Ding, Zijing

2018-01-01

We consider the motion of a gravity-driven flow down a vertical fiber subjected to a radial electric field. This flow exhibits rich dynamics including the formation of droplets, or beads, driven by a Rayleigh-Plateau mechanism modified by the presence of gravity as well as the Maxwell stress at the interface. A spatiotemporal stability analysis is performed to investigate the effect of electric field on the absolute-convective instability (AI-CI) characteristics. We performed a numerical simulation on the nonlinear evolution of the film to examine the transition from CI to AI regime. The numerical results are in excellent agreement with the spatiotemporal stability analysis. The blowup behavior of nonlinear simulation predicts the formation of touchdown singularity of the interface due to the effect of electric field. We try to connect the blowup behavior with the AI-CI characteristics. It is found that the singularities mainly occur in the AI regime. The results indicate that the film may have a tendency to form very sharp tips due to the enhancement of the absolute instability induced by the electric field. We perform a theoretical analysis to study the behaviors of the singularities. The results show that there exists a self-similarity between the temporal and spatial distances from the singularities.

Self-attraction effect and correction on the T-1 absolute gravimeter

NASA Astrophysics Data System (ADS)

Li, Z.; Hu, H.; Wu, K.; Li, G.; Wang, G.; Wang, L. J.

2015-12-01

The self-attraction effect (SAE) in an absolute gravimeter is a kind of systematic error due to the gravitation of the instrument to the falling object. This effect depends on the mass distribution of the gravimeter, and is estimated to be a few microgals (1 μGal  =  10-8 m s-2) for the FG5 gravimeter. In this paper, the SAE of a home-made T-1 absolute gravimeter is analyzed and calculated. Most of the stationary components, including the dropping chamber, the laser interferometer, the vibration isolation device and two tripods, are finely modelled, and the related SAEs are computed. In addition, the SAE of the co-falling carriage inside the dropping chamber is carefully calculated because the distance between the falling object and the co-falling carriage varies during the measurement. In order to get the correction of the SAE, two different methods are compared. One is to linearize the SAE curve, the other one is to calculate the perturbed trajectory. The results from these two methods agree with each other within 0.01 μGal. With an uncertainty analysis, the correction of the SAE of the T-1 gravimeter is estimated to be (-1.9  ±  0.1) μGal.

Observational Model for Precision Astrometry with the Space Interferometry Mission

NASA Technical Reports Server (NTRS)

Turyshev, Slava G.; Milman, Mark H.

2000-01-01

The Space Interferometry Mission (SIM) is a space-based 10-m baseline Michelson optical interferometer operating in the visible waveband that is designed to achieve astrometric accuracy in the single digits of the microarcsecond domain. Over a narrow field of view SIM is expected to achieve a mission accuracy of 1 microarcsecond. In this mode SIM will search for planetary companions to nearby stars by detecting the astrometric "wobble" relative to a nearby reference star. In its wide-angle mode, SIM will provide 4 microarcsecond precision absolute position measurements of stars, with parallaxes to comparable accuracy, at the end of its 5-year mission. The expected proper motion accuracy is around 3 microarcsecond/year, corresponding to a transverse velocity of 10 m/ s at a distance of 1 kpc. The basic astrometric observable of the SIM instrument is the pathlength delay. This measurement is made by a combination of internal metrology measurements that determine the distance the starlight travels through the two arms of the interferometer, and a measurement of the white light stellar fringe to find the point of equal pathlength. Because this operation requires a non-negligible integration time, the interferometer baseline vector is not stationary over this time period, as its absolute length and orientation are time varying. This paper addresses how the time varying baseline can be "regularized" so that it may act as a single baseline vector for multiple stars, as required for the solution of the astrometric equations.

Gd(III)-Gd(III) EPR distance measurements--the range of accessible distances and the impact of zero field splitting.

PubMed

Dalaloyan, Arina; Qi, Mian; Ruthstein, Sharon; Vega, Shimon; Godt, Adelheid; Feintuch, Akiva; Goldfarb, Daniella

2015-07-28

Gd(III) complexes have emerged as spin labels for distance determination in biomolecules through double-electron-electron resonance (DEER) measurements at high fields. For data analysis, the standard approach developed for a pair of weakly coupled spins with S = 1/2 was applied, ignoring the actual properties of Gd(III) ions, i.e. S = 7/2 and ZFS (zero field splitting) ≠ 0. The present study reports on a careful investigation on the consequences of this approach, together with the range of distances accessible by DEER with Gd(III) complexes as spin labels. The experiments were performed on a series of specifically designed and synthesized Gd-rulers (Gd-PyMTA-spacer-Gd-PyMTA) covering Gd-Gd distances of 2-8 nm. These were dissolved in D2O-glycerol-d8 (0.03-0.10 mM solutions) which is the solvent used for the corresponding experiments on biomolecules. Q- and W-band DEER measurements, followed by data analysis using the standard data analysis approach, used for S = 1/2 pairs gave the distance-distribution curves, of which the absolute maxima agreed very well with the expected distances. However, in the case of the short distances of 2.1 and 2.9 nm, the distance distributions revealed additional peaks. These are a consequence of neglecting the pseudo-secular term in the dipolar Hamiltonian during the data analysis, as is outlined in a theoretical treatment. At distances of 3.4 nm and above, disregarding the pseudo-secular term leads to a broadening of a maximum of 0.4 nm of the distance-distribution curves at half height. Overall, the distances of up to 8.3 nm were determined, and the long evolution time of 16 μs at 10 K indicates that a distance of up to 9.4 nm can be accessed. A large distribution of the ZFS parameter, D, as is found for most Gd(III) complexes in a frozen solution, is crucial for the application of Gd(III) complexes as spin labels for distance determination via Gd(III)-Gd(III) DEER, especially for short distances. The larger ZFS of Gd-PyMTA, in comparison to that of Gd-DOTA, makes Gd-PyMTA a better label for short distances.

Femorofemoral bypass grafting in high-risk patients.

PubMed

Deruyter, L; Caes, F; Van den Brande, P; Cham, B; Welch, W

1986-01-01

A total of 37 extra-anatomic femorofemoral bypasses were inserted for severe unilateral iliac artery stenosis or a thrombosed graft limb of an aorto-bifemoral bifurcation graft. All patients were severely debilitated and at high risk for direct aorto-iliac reconstruction. 30% suffered severe claudication; 70% had ischemic restpain or trophic lesions. 43% died during a mean follow-up period of 17 months. This study demonstrates that the extra-anatomic femoro-femoral bypass procedure is an effective alternative therapeutic modality for high-risk patients with an acceptable operative mortality (5.4%) and morbidity to improve the quality of life.

Prospective, multicenter study of endovascular repair of aortoiliac and iliac aneurysms using the Gore Iliac Branch Endoprosthesis.

PubMed

Schneider, Darren B; Matsumura, Jon S; Lee, Jason T; Peterson, Brian G; Chaer, Rabih A; Oderich, Gustavo S

2017-09-01

The GORE EXCLUDER Iliac Branch Endoprosthesis (IBE; W. L. Gore and Associates, Flagstaff, Ariz) is an iliac branch stent graft system designed to preserve internal iliac artery perfusion during endovascular repair of aortoiliac aneurysms (AIAs) and common iliac artery (CIA) aneurysms (CIAAs). We report the 6-month primary end point results of the IBE 12-04 United States pivotal trial for endovascular treatment of AIAs and CIAAs using the IBE device. The trial prospectively enrolled 63 patients with AIA or CIAA who underwent implantation of the IBE device at 28 centers in the United States from 2013 to 2015. All patients underwent placement of a single IBE device. Twenty-two patients (34.9%) with bilateral CIAs were enrolled after undergoing staged coil or plug embolization (21 of 22) or surgical revascularization (1 of 22) of the contralateral internal iliac artery. Follow-up at 30 days and 6 months included clinical assessment and computed tomography angiography evaluation as assessed by an independent core laboratory. The primary effectiveness end point was freedom from IBE limb occlusion and reintervention for type I or III endoleak and ≥60% stenosis at 6 months, and the secondary effectiveness end point was freedom from new onset of buttock claudication on the IBE side at 6 months. Mean CIA diameter on the IBE side was 41.0 ± 11.4 mm (range, 25.2-76.3 mm). There were no procedural deaths, and technical success, defined as successful deployment and patency of all IBE components and freedom from type I or III endoleak, was 95.2% (60 of 63). Data for 61 patients were available for primary and secondary effectiveness end point analysis. Internal iliac limb patency was 95.1% (58 of 61), and no new type I or III endoleaks or device migrations were observed at 6 months. The three patients with loss of internal iliac limb patency were asymptomatic, and freedom from new-onset buttock claudication on the IBE side was 100% at 6 months. New-onset buttock claudication occurred on the non-IBE treatment side in six of 21 patients (28.6%) who underwent staged internal iliac artery coil embolization. These results confirm that the IBE device is effective at treating CIAAs and AIAs, maintaining blood flow into the internal iliac artery, and avoiding complications associated with internal iliac artery sacrifice. Follow-up will be continued for 5 years to establish the long-term durability of iliac aneurysm repair with the IBE device. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

A functional murine model of hindlimb demand ischemia.

PubMed

Peck, Michael A; Crawford, Robert S; Abularrage, Christopher J; Patel, Virendra I; Conrad, Mark F; Yoo, Jin Hyung; Watkins, Michael T; Albadawi, Hassan

2010-05-01

To date, murine models of treadmill exercise have been used to study general exercise physiology and angiogenesis in ischemic hindlimbs. The purpose of these experiments was to develop a murine model of demand ischemia in an ischemic limb to mimic claudication in humans. The primary goal was to determine whether treadmill exercise reflected a hemodynamic picture which might be consistent with the hyperemic response observed in humans. Aged hypercholesterolemic ApoE null mice (ApoE(-/-), n = 13) were subjected to femoral artery ligation (FAL) and allowed to recover from the acute ischemic response. Peripheral perfusion of the hindlimbs at rest was determined by serial evaluation using laser Doppler imaging (LDI) on days 0, 7, and 14 following FAL. During the experiments, mice were also assessed on an established five-point clinical ischemic score, which assessed the degree of digital amputation, necrosis, and cyanosis compared to the nonischemic contralateral limb. After stabilization of the LDI ratio (ischemic limb flux/contralateral nonischemic limb flux) and clinical ischemic score, mice underwent 2 days of treadmill training (10 min at 10 m/min, incline of 10 degrees ) followed by 60 min of daily treadmill exercise (13 m/min, incline of 10 degrees ) through day 25. An evaluation of preexercise and postexercise perfusion using LDI was performed on two separate occasions following the onset of daily exercise. During the immediate 15 min postexercise evaluation, LDI scanning was obtained in quadruplicate, to allow identification of peak flux ratios. Statistical analysis included unpaired t-tests and analysis of variance. After FAL, the LDI flux ratio reached a nadir between days 1 and 2, then stabilized by day 14 and remained stable through day 25. The clinical ischemic score stabilized at day 7 and remained stable throughout the rest of the experiment. Based on stabilization of both the clinical ischemic score and LDI ratio, exercise training began on day 15. The peak 15 min postexercise LDI ratio increased significantly compared to the preexercise ratio on day 17 (0.48 +/- 0.04 vs. 0.34 +/- 0.04, p < 0.05) and day 25 (0.37 +/- 0.03 vs. 0.27 +/- 0.03, p < 0.01). Within 2 hr of exercise, the LDI ratio returned to preexercise levels on both days 17 and 25. Clinical and hemodynamic stabilization of limb perfusion is evident by 14 days after FAL. FAL followed by demand ischemia results in a reversible relative hyperemic response similar to that observed in exercising human claudicants. A murine model of FAL associated with demand ischemia may be useful to evaluate the metabolic, inflammatory, and flow-related changes associated with claudication in humans. Copyright 2010 Annals of Vascular Surgery Inc. All rights reserved.

Learning your way in a city: experience and gender differences in configurational knowledge of one's environment.

PubMed

De Goede, Maartje; Postma, Albert

2015-01-01

Males tend to outperform females in their knowledge of relative and absolute distances in spatial layouts and environments. It is unclear yet in how far these differences are innate or develop through life. The aim of the present study was to investigate whether gender differences in configurational knowledge for a natural environment might be modulated by experience. In order to examine this possibility, distance as well as directional knowledge of the city of Utrecht in the Netherlands was assessed in male and female inhabitants who had different levels of familiarity with this city. Experience affected the ability to solve difficult distance knowledge problems, but only for females. While the quality of the spatial representation of metric distances improved with more experience, this effect was not different for males and females. In contrast directional configurational measures did show a main gender effect but no experience modulation. In general, it seems that we obtain different configurational aspects according to different experiential time schemes. Moreover, the results suggest that experience may be a modulating factor in the occurrence of gender differences in configurational knowledge, though this seems dependent on the type of measurement. It is discussed in how far proficiency in mental rotation ability and spatial working memory accounts for these differences.

Learning your way in a city: experience and gender differences in configurational knowledge of one’s environment

PubMed Central

De Goede, Maartje; Postma, Albert

2015-01-01

Males tend to outperform females in their knowledge of relative and absolute distances in spatial layouts and environments. It is unclear yet in how far these differences are innate or develop through life. The aim of the present study was to investigate whether gender differences in configurational knowledge for a natural environment might be modulated by experience. In order to examine this possibility, distance as well as directional knowledge of the city of Utrecht in the Netherlands was assessed in male and female inhabitants who had different levels of familiarity with this city. Experience affected the ability to solve difficult distance knowledge problems, but only for females. While the quality of the spatial representation of metric distances improved with more experience, this effect was not different for males and females. In contrast directional configurational measures did show a main gender effect but no experience modulation. In general, it seems that we obtain different configurational aspects according to different experiential time schemes. Moreover, the results suggest that experience may be a modulating factor in the occurrence of gender differences in configurational knowledge, though this seems dependent on the type of measurement. It is discussed in how far proficiency in mental rotation ability and spatial working memory accounts for these differences. PMID:25914663

CCD Photometry of Cometary Nuclei, I: Observations from 1990-1995

NASA Astrophysics Data System (ADS)

Licandro, Javier; Tancredi, Gonzalo; Lindgren, Mats; Rickman, Hans; Hutton, Ricardo Gil

2000-09-01

CCD photometry of 18 Jupiter family comets, observed at medium and large heliocentric distances, was carried out between April 1990 and July 1995. This is part of a long-term observational program designed to obtain their nuclear magnitudes. The observations were made with the 1.54-m Danish Telescope at ESO La Silla, the 2.5-m Nordic Optical Telescope (NOT) at Observatorio del Roque de los Muchachos (La Palma), the 2.0-m telescope at Pic du Midi, and the 2.15-m telescope at CASLEO, Argentina. Our estimates of the absolute nuclear magnitudes are discussed in comparison with previous determinations. Estimates (sometimes upper limits) for the effective radius ( R) of the nuclei are computed considering a typical geometric albedo pv=0.04. The lowest radius found is the one of 37P/Forbes ( R=1.0 km) while the largest corresponds to 65P/Gunn ( R=11.0 km), but in this case the comet was observed very active. Wherever possible, cometary image profiles are compared with stellar profiles, in order to determine the existence of a faint coma. Seven of the comets were active, six of them at heliocentric distances larger than 4 AU. This unexpected activity is also discussed. We find a strong correlation between activity at large heliocentric distances and recent downward jumps in perihelion distance.

Determination of electrostatic force and its characteristics based on phase difference by amplitude modulation atomic force microscopy

NASA Astrophysics Data System (ADS)

Wang, Kesheng; Cheng, Jia; Yao, Shiji; Lu, Yijia; Ji, Linhong; Xu, Dengfeng

2016-12-01

Electrostatic force measurement at the micro/nano scale is of great significance in science and engineering. In this paper, a reasonable way of applying voltage is put forward by taking an electrostatic chuck in a real integrated circuit manufacturing process as a sample, applying voltage in the probe and the sample electrode, respectively, and comparing the measurement effect of the probe oscillation phase difference by amplitude modulation atomic force microscopy. Based on the phase difference obtained from the experiment, the quantitative dependence of the absolute magnitude of the electrostatic force on the tip-sample distance and applied voltage is established by means of theoretical analysis and numerical simulation. The results show that the varying characteristics of the electrostatic force with the distance and voltage at the micro/nano scale are similar to those at the macroscopic scale. Electrostatic force gradually decays with increasing distance. Electrostatic force is basically proportional to the square of applied voltage. Meanwhile, the applicable conditions of the above laws are discussed. In addition, a comparison of the results in this paper with the results of the energy dissipation method shows the two are consistent in general. The error decreases with increasing distance, and the effect of voltage on the error is small.

Childhood cancer incidence in relation to distance from the former nuclear testing site in Semipalatinsk, Kazakhstan.

PubMed

Zaridze, D G; Li, N; Men, T; Duffy, S W

1994-11-15

Rates of childhood cancer between 1981 and 1990 in the 4 administrative zones of Kazakhstan were studied to assess the relationship, if any, with distance from nuclear testing sites. Risk of various cancers among children aged 14 years or younger were estimated in relation to distance from (1) a site where testing in air was performed before 1963, (2) a site where underground testing took place thereafter, and (3) a reservoir, known as "Atom Lake," created by 4 nuclear explosions in 1965. Risk of acute leukaemia rose significantly with increasing proximity of residence to the testing areas, although the absolute value of the risk gradient was relatively small. The relative risk for those living less than 200 km from the air-testing site was 1.76 compared with those living 400 km or more away from the site. Similar relative risks were observed for the underground site and "Atom Lake." There was also some evidence of increased risk of brain tumours in association with proximity to the test sites. In 2 of the 4 zones studied, there was substantial regional variation in acute leukaemia rates which was not attributable to distance from the test site. The findings may be affected by potential confounders, notably urban/rural status and ethnic factors.

Serendipitous discovery of a faint dwarf galaxy near a Local Volume dwarf

NASA Astrophysics Data System (ADS)

Makarova, L. N.; Makarov, D. I.; Antipova, A. V.; Karachentsev, I. D.; Tully, R. B.

2018-03-01

A faint dwarf irregular galaxy has been discovered in the HST/ACS field of LV J1157+5638. The galaxy is resolved into individual stars, including the brightest magnitude of the red giant branch. The dwarf is very likely a physical satellite of LV J1157+5638. The distance modulus of LV J1157+5638 using the tip of the red giant branch (TRGB) distance indicator is 29.82 ± 0.09 mag (D = 9.22 ± 0.38 Mpc). The TRGB distance modulus of LV J1157+5638 sat is 29.76 ± 0.11 mag (D = 8.95 ± 0.42 Mpc). The distances to the two galaxies are consistent within the uncertainties. The projected separation between them is only 3.9 kpc. LV J1157+5638 has a total absolute V magnitude of -13.26 ± 0.10 and linear Holmberg diameter of 1.36 kpc, whereas its faint satellite LV J1157+5638 sat has MV = -9.38 ± 0.13 mag and Holmberg diameter of 0.37 kpc. Such a faint dwarf was discovered for the first time beyond the nearest 4 Mpc from us. The presence of main-sequence stars in both galaxies unambiguously indicates the classification of the objects as dwarf irregulars with recent or ongoing star formation events in both galaxies.

Life on the edge: carnivore body size variation is all over the place

PubMed Central

Meiri, Shai; Dayan, Tamar; Simberloff, Daniel; Grenyer, Richard

2009-01-01

Evolutionary biologists have long been fascinated by both the ways in which species respond to ecological conditions at the edges of their geographic ranges and the way that species' body sizes evolve across their ranges. Surprisingly, though, the relationship between these two phenomena is rarely studied. Here, we examine whether carnivore body size changes from the interior of their geographic range towards the range edges. We find that within species, body size often varies strongly with distance from the range edge. However, there is no general tendency across species for size to be either larger or smaller towards the edge. There is some evidence that the smallest guild members increase in size towards their range edges, but results for the largest guild members are equivocal. Whether individuals vary in relation to the distance from the range edges often depends on the way edge and interior are defined. Neither geographic range size nor absolute body size influences the tendency of size to vary with distance from the range edge. Therefore, we suggest that the frequent significant association between body size and the position of individuals along the edge-core continuum reflects the prevalence of geographic size variation and that the distance to range edge per se does not influence size evolution in a consistent way. PMID:19324818

Water Sensation During Passive Propulsion for Expert and Nonexpert Swimmers.

PubMed

Kusanagi, Kenta; Sato, Daisuke; Hashimoto, Yasuhiro; Yamada, Norimasa

2017-06-01

This study determined whether expert swimmers, compared with nonexperts, have superior movement perception and physical sensations of propulsion in water. Expert (national level competitors, n = 10) and nonexpert (able to swim 50 m in > 3 styles, n = 10) swimmers estimated distance traveled in water with their eyes closed. Both groups indicated their subjective physical sensations in the water. For each of two trials, two-dimensional coordinates were obtained from video recordings using the two-dimensional direct linear transformation method for calculating changes in speed. The mean absolute error of the difference between the actual and estimated distance traveled in the water was significantly lower for expert swimmers (0.90 ± 0.71 meters) compared with nonexpert swimmers (3.85 ± 0.84 m). Expert swimmers described the sensation of propulsion in water in cutaneous terms as the "sense of flow" and sensation of "skin resistance." Therefore, expert swimmers appear to have a superior sense of distance during their movement in the water compared with that of nonexpert swimmers. In addition, expert swimmers may have a better perception of movement in water. We propose that expert swimmers integrate sensations and proprioceptive senses, enabling them to better perceive and estimate distance moved through water.

Time reversal for localization of sources of infrasound signals in a windy stratified atmosphere.

PubMed

Lonzaga, Joel B

2016-06-01

Time reversal is used for localizing sources of recorded infrasound signals propagating in a windy, stratified atmosphere. Due to the convective effect of the background flow, the back-azimuths of the recorded signals can be substantially different from the source back-azimuth, posing a significant difficulty in source localization. The back-propagated signals are characterized by negative group velocities from which the source back-azimuth and source-to-receiver (STR) distance can be estimated using the apparent back-azimuths and trace velocities of the signals. The method is applied to several distinct infrasound arrivals recorded by two arrays in the Netherlands. The infrasound signals were generated by the Buncefield oil depot explosion in the U.K. in December 2005. Analyses show that the method can be used to substantially enhance estimates of the source back-azimuth and the STR distance. In one of the arrays, for instance, the deviations between the measured back-azimuths of the signals and the known source back-azimuth are quite large (-1° to -7°), whereas the deviations between the predicted and known source back-azimuths are small with an absolute mean value of <1°. Furthermore, the predicted STR distance is off only by <5% of the known STR distance.

A Comparative Study of Precise Point Positioning (PPP) Accuracy Using Online Services

NASA Astrophysics Data System (ADS)

Malinowski, Marcin; Kwiecień, Janusz

2016-12-01

Precise Point Positioning (PPP) is a technique used to determine the position of receiver antenna without communication with the reference station. It may be an alternative solution to differential measurements, where maintaining a connection with a single RTK station or a regional network of reference stations RTN is necessary. This situation is especially common in areas with poorly developed infrastructure of ground stations. A lot of research conducted so far on the use of the PPP technique has been concerned about the development of entire day observation sessions. However, this paper presents the results of a comparative analysis of accuracy of absolute determination of position from observations which last between 1 to 7 hours with the use of four permanent services which execute calculations with PPP technique such as: Automatic Precise Positioning Service (APPS), Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP), GNSS Analysis and Positioning Software (GAPS) and magicPPP - Precise Point Positioning Solution (magicGNSS). On the basis of acquired results of measurements, it can be concluded that at least two-hour long measurements allow acquiring an absolute position with an accuracy of 2-4 cm. An evaluation of the impact on the accuracy of simultaneous positioning of three points test network on the change of the horizontal distance and the relative height difference between measured triangle vertices was also conducted. Distances and relative height differences between points of the triangular test network measured with a laser station Leica TDRA6000 were adopted as references. The analyses of results show that at least two hours long measurement sessions can be used to determine the horizontal distance or the difference in height with an accuracy of 1-2 cm. Rapid products employed in calculations conducted with PPP technique reached the accuracy of determining coordinates on a close level as in elaborations which employ Final products.

Age-Distance Relations along the Hawaiian-Emperor Volcanic Chain: History and Current Status

NASA Astrophysics Data System (ADS)

Clague, D. A.

2016-12-01

The increase in age with distance along the Hawaiian-Emperor volcanic chain is a key parameter in models of plate motions and mantle dynamics. Wilson (1963) proposed that the Hawaiian Islands formed sequentially as the Pacific Plate migrated over a hot spot in the Earth's mantle based on the inferred increase in age of the Islands to the west. Morgan (1971) proposed that Wilson's hot spot was a geographically fixed mantle plume originating at the core-mantle boundary, and that the orientation and age-distance relations of the chain provided a measure of absolute plate motion with the bend between the Hawaiian and Emperor chains reflecting a major change in motion of the Pacific Plate at 40 Ma. Defining and refining the age relations along the two chains has taken decades due largely to the remoteness of most of the chain, the difficulties in dating altered submarine lavas, and the presence of glacial debris as far south as 42°25'N in the Emperor Seamounts. Ocean drilling program legs 55 and 197 focused on the age and paleolatitude of Emperor Seamounts. Many of the early ages are K-Ar dates. Later dates are Ar/Ar incremental heating extractions of whole-rocks or, more recently still, of clean mineral separates that yield accurate and precise dates (e.g., Sharp and Clague, 2006). Many reported ages have ill-defined errors, especially those of tholeiitic shield lavas. Over-interpretation of the collected age data seemed to indicate coeval volcanism along large segments of the chain, instead of recognizing the errors inherent in many of the determined ages. Subsequent work, such as at Gardner Pinnacles, has eliminated some of these apparent non-linear age relations. The bend is now recognized as a gradual transition in orientation that occurred between 50 and 42 Ma (Sharp & Clague, 2006); it likely resulted from the collision of India and Eurasia that precipitated a worldwide chain reaction of relative and absolute plate motion changes (Dalrymple & Clague, 1976).

The trend of production rates with heliocentric distance for comet P/Halley

NASA Technical Reports Server (NTRS)

Fink, Uwe

1994-01-01

Comet P/Halley was observed spectroscopically in the wavelength range 5200-10,400 A during 10 observing runs, roughly a month apart from 1985 August 28 to 1986 June 6. The observations span a heliocentric distance from 0.73 to 2.52 AU. This data set is analyzed to determine the course of the production rate with heliocentric distance for C2, NH2, CN, and the continuum. The effect of changing the Haser scale lengths and their heliocentric distance dependence is examined. The production rate ratios to water change only in a minor way, but the absolute values of the production rates are more severely affected. Fluorescent efficiencies, or g-factors for the CN red system are calculated, and band intensity ratios for NH2 and CN are presented. Using presently available fluorescence efficiencies and Haser scale lengths, mixing ratios for the parents of C2, CN, and NH2 with respect to water are: 0.34 +/- 0.07%, 0.15 +/- 0.04%, and 0.13 +/- 0.05%. It is found that these mixing ratios are essentially constant over the heliocentric distance range of the observations, implying a rather uniform nucleus and uniform outgassing characteristics, although there are indications of smaller scale day-to-day variations. The results provide strong observational confirmation that water evaporation controls the activity of the comet over the distance range studied. Continuum values Af rho are determined, and their ratios to QH2O are found to have a clear dependence with heliocentric distance approximately r(exp -1.0) with a post-perihelion enhancement. No correlation of the production rate ratios with light curve of P/Halley were found, nor was there any correlation of the C2 or CN production with the dust.

The Gould’s Belt Distances Survey (GOBELINS). I. Trigonometric Parallax Distances and Depth of the Ophiuchus Complex

NASA Astrophysics Data System (ADS)

Ortiz-León, Gisela N.; Loinard, Laurent; Kounkel, Marina A.; Dzib, Sergio A.; Mioduszewski, Amy J.; Rodríguez, Luis F.; Torres, Rosa M.; González-Lópezlira, Rosa A.; Pech, Gerardo; Rivera, Juana L.; Hartmann, Lee; Boden, Andrew F.; Evans, Neal J., II; Briceño, Cesar; Tobin, John J.; Galli, Phillip A. B.; Gudehus, Donald

2017-01-01

We present the first results of the Gould’s Belt Distances Survey (GOBELINS), a project aimed at measuring the proper motion and trigonometric parallax of a large sample of young stars in nearby regions using multi-epoch Very Long Baseline Array (VLBA) radio observations. Enough VLBA detections have now been obtained for 16 stellar systems in Ophiuchus to derive their parallax and proper motion. This leads to distance determinations for individual stars with an accuracy of 0.3 to a few percent. In addition, the orbits of six multiple systems were modelled by combining absolute positions with VLBA (and, in some cases, near-infrared) angular separations. Twelve stellar systems are located in the dark cloud Lynds 1688 the individual distances for this sample are highly consistent with one another and yield a mean parallax for Lynds 1688 of \\varpi =7.28+/- 0.06 mas, corresponding to a distance d=137.3+/- 1.2 pc. This represents an accuracy greater than 1%. Three systems for which astrometric elements could be measured are located in the eastern streamer (Lynds 1689) and yield an estimate of \\varpi =6.79+/- 0.16 mas, corresponding to a distance d=147.3+/- 3.4 pc. This suggests that the eastern streamer is located about 10 pc farther than the core, but this conclusion needs to be confirmed by observations of additional sources in the eastern streamer (currently being collected). From the measured proper motions, we estimate the one-dimensional velocity dispersion in Lynds 1688 to be 2.8 ± 1.8 and 3.0 ± 2.0 km s-1, in R.A. and decl., respectively; these are larger than, but still consistent within 1σ of, those found in other studies.

Precise Distances for Main-belt Asteroids in Only Two Nights

NASA Astrophysics Data System (ADS)

Heinze, Aren N.; Metchev, Stanimir

2015-10-01

We present a method for calculating precise distances to asteroids using only two nights of data from a single location—far too little for an orbit—by exploiting the angular reflex motion of the asteroids due to Earth’s axial rotation. We refer to this as the rotational reflex velocity method. While the concept is simple and well-known, it has not been previously exploited for surveys of main belt asteroids (MBAs). We offer a mathematical development, estimates of the errors of the approximation, and a demonstration using a sample of 197 asteroids observed for two nights with a small, 0.9-m telescope. This demonstration used digital tracking to enhance detection sensitivity for faint asteroids, but our distance determination works with any detection method. Forty-eight asteroids in our sample had known orbits prior to our observations, and for these we demonstrate a mean fractional error of only 1.6% between the distances we calculate and those given in ephemerides from the Minor Planet Center. In contrast to our two-night results, distance determination by fitting approximate orbits requires observations spanning 7-10 nights. Once an asteroid’s distance is known, its absolute magnitude and size (given a statistically estimated albedo) may immediately be calculated. Our method will therefore greatly enhance the efficiency with which 4m and larger telescopes can probe the size distribution of small (e.g., 100 m) MBAs. This distribution remains poorly known, yet encodes information about the collisional evolution of the asteroid belt—and hence the history of the Solar System.

The relationship between relative deprivation and self-rated health among Palestinian women in refugee camps in Lebanon.

PubMed

Salti, Nisreen; Abdulrahim, Sawsan

2016-12-01

Relative deprivation (RD) has been advanced as a theory to explain the relationship between income inequality and health in high-income countries. In this study, we tested the theory in a low-income protracted refugee setting in a middle-income country. Using data from the 2010 Socioeconomic Survey of Palestine Refugees in Lebanon, we examined the relationship between RD and health among a representative sample of Palestinian refugee women ( N =1047). Data were gathered utilizing a household questionnaire with information on socio-demographics and an individual-level questionnaire with information on the health of each respondent. We examined self-rated health (SRH) as the main health measure but also checked the sensitivity of our results using self-reported chronic conditions. We used two measures for absolute SES: total household monthly expenditures on non-food goods and services and total household monthly expenditures on non-health goods and services. With refugee camp as a reference group, we measured a household's RD as a household's rank of absolute SES within the reference group, multiplied by the distance between its absolute SES and the average absolute SES of all households ranked above it. We investigated the robustness of the RD-SRH relationship using these two alternative measures of absolute SES. Our findings show that, controlling for absolute SES and other possible confounders, women report significantly poorer health when they live in households with a higher score on our RD measure (because of either lower relative rank or lower relative SES compared to households better off in the reference group which we take to be the refugee camp). While RD is always significant as a determinant of SRH under a variety of specifications, absolute SES is not consistently significant. These findings persist when we use self-reported chronic conditions as our measure of health instead of SRH, suggesting that the relationship between health and RD may be operating through a psychosocial mechanism. Our findings underscore the importance of examining RD under conditions of poverty and in diverse socio-cultural contexts. They also highlight that public health approaches should be concerned with reducing social inequalities in low-income settings in addition to alleviating poverty.

[Healthcare Provider Professional Secrecy: an Issue for Public Health Democracy somewhere between Immanence and Alienation.

PubMed

Pautier, Silvère

2017-09-01

For a long time considered as total and absolute, healthcare professional secrecy is today difficult to reconcile with care practices. Lots of paradoxes question its preservation in favour of general interest and public order against the protection of private interest within an individualistic normative society. Exploring this interrogation, the article's objective is to initiate an ethical discussion from a professional caregiver secrecy's historical and sociological evolution perspective. Thus, with the help of theoretical understandings, especially those by Michel Foucault, medical secrecy is considered a defense of rationality specific to populations' government. This conceptualization finds arguments through social collective norms attached to an alienating biopower at the expense of secrecy integrated as an individualistic and immanent social norm. However, beyond the well-known debate on the absolute necessity for change, evolution… the distance from the Socratic and Hippocratic principles engage people and society in real democratic decisions about Health. Also, health professionals, patients, usgers and society must consider the limits that would lead to medical confidentiality.

Absolute Nuv magnitudes of Gaia DR1 astrometric stars and a search for hot companions in nearby systems

NASA Astrophysics Data System (ADS)

Makarov, V. V.

2017-10-01

Accurate parallaxes from Gaia DR1 (TGAS) are combined with GALEX visual Nuv magnitudes to produce absolute Mnuv magnitudes and an ultraviolet HR diagram for a large sample of astrometric stars. A functional fit is derived of the lower envelope main sequence of the nearest 1403 stars (distance <40 pc), which should be reddening-free. Using this empirical fit, 50 nearby stars are selected with significant Nuv excess. These are predominantly late K and early M dwarfs, often associated with X-ray sources, and showing other manifestations of magnetic activity. The sample may include systems with hidden white dwarfs, stars younger than the Pleiades, or, most likely, tight interacting binaries of the BY Dra-type. A separate collection of 40 stars with precise trigonometric parallaxes and Nuv-G colors bluer than 2 mag is presented. It includes several known novae, white dwarfs, and binaries with hot subdwarf (sdOB) components, but most remain unexplored.

Electric fields and vector potentials of thin cylindrical antennas

NASA Astrophysics Data System (ADS)

King, Ronold W. P.

1990-09-01

The vector potential and electric field generated by the current in a center-driven or parasitic dipole antenna that extends from z = -h to z = h are investigated for each of the several components of the current. These include sin k(h - absolute value of z), sin k (absolute value of z) - sin kh, cos kz - cos kh, and cos kz/2 - cos kh/2. Of special interest are the interactions among the variously spaced elements in parallel nonstaggered arrays. These depend on the mutual vector potentials. It is shown that at a radial distance rho approximately = h and in the range z = -h to h, the vector potentials due to all four components become alike and have an approximately plane-wave form. Simple approximate formulas for the electric fields and vector potentials generated by each of the four distributions are derived and compared with the exact results. The application of the new formulas to large arrays is discussed.

Study of ground state optical transfer for ultracold alkali dimers

NASA Astrophysics Data System (ADS)

Bouloufa-Maafa, Nadia; Londono, Beatriz; Borsalino, Dimitri; Vexiau, Romain; Mahecha, Jorge; Dulieu, Olivier; Luc-Koenig, Eliane

2013-05-01

Control of molecular states by laser pulses offer promising potential applications. The manipulation of molecules by external fields requires precise knowledge of the molecular structure. Our motivation is to perform a detailed analysis of the spectroscopic properties of alkali dimers, with the aim to determine efficient optical paths to form molecules in the absolute ground state and to determine the optimal parameters of the optical lattices where those molecules are manipulated to avoid losses by collisions. To this end, we use state of the art molecular potentials, R-dependent spin-orbit coupling and transition dipole moment to perform our calculations. R-dependent SO coupling are of crucial importance because the transitions occur at internuclear distances where they are affected by this R-dependence. Efficient schemes to transfer RbCs, KRb and KCs to the absolute ground state as well as the optimal parameters of the optical lattices will be presented. This work was supported in part by ``Triangle de la Physique'' under contract 2008-007T-QCCM (Quantum Control of Cold Molecules).

Supercontinent Succession and the Calculation of Absolute Paleolongitude

NASA Astrophysics Data System (ADS)

Mitchell, R. N.; Kilian, T.; Evans, D. A.

2010-12-01

Where will the next supercontinent form? Traditional ‘introversion’ and ‘extraversion’ models of supercontinent succession predict that Super Asia will respectively form whence Pangea was or on the opposite side of the world. We develop the ‘orthoversion’ model whereby a succeeding supercontinent forms 90° away: somewhere along the great circle of subduction encircling its relict predecessor—a mantle topology that arises when supercontinents develop return flow beneath their mature centroids. This centroid defines the minimum moment of inertia (I_min) about which rapid and oscillatory true polar wander occurs owing to the prolate shape of nonhydrostatic Earth. Fitting great circles to each supercontinent’s true polar wander legacy, we determine that the distances between successive supercontinent centers (I_min axes) are 88° and 87° for Nuna→Rodinia and Rodinia→Pangea, respectively—both as predicted by the orthoversion model. Not only can supercontinent centers be pinned back into Precambrian time, they provide fixed points for the calculation of absolute paleolongitude.

Angular scale expansion theory and the misperception of egocentric distance in locomotor space.

PubMed

Durgin, Frank H

Perception is crucial for the control of action, but perception need not be scaled accurately to produce accurate actions. This paper reviews evidence for an elegant new theory of locomotor space perception that is based on the dense coding of angular declination so that action control may be guided by richer feedback. The theory accounts for why so much direct-estimation data suggests that egocentric distance is underestimated despite the fact that action measures have been interpreted as indicating accurate perception. Actions are calibrated to the perceived scale of space and thus action measures are typically unable to distinguish systematic (e.g., linearly scaled) misperception from accurate perception. Whereas subjective reports of the scaling of linear extent are difficult to evaluate in absolute terms, study of the scaling of perceived angles (which exist in a known scale, delimited by vertical and horizontal) provides new evidence regarding the perceptual scaling of locomotor space.

Distribution, enrichment and accumulation of heavy metals in coastal sediments of Alang-Sosiya ship scrapping yard, India.

PubMed

Reddy, M Srinivasa; Basha, Shaik; Sravan Kumar, V G; Joshi, H V; Ramachandraiah, G

2004-06-01

Since its inception in 1982, the Alang-Sosiya yard has become the largest ship scrapping works in the world. Several hundreds of ships arrive every year. The degree of heavy metal contamination has been studied in bulk and fine sediments from the intertidal zone of this ship scrapping yard, two stations, one on either side at 5 km distance and one reference station 60 km distance near Mahuva, towards the south. The samples have been subjected to a total digestion technique and analysed for elements: Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Zn and Al, and %TOC. The absolute metal concentrations reflected variations in BF and FF sediment samples with organic matter content. Enrichment factors (EF) and geoaccumulation indices (Igeo) have been calculated and the relative contamination levels are assessed at these sites. At Alang-Sosiya, the enrichment of heavy metals has been observed to be relatively high.

A new type industrial total station based on target automatic collimation

NASA Astrophysics Data System (ADS)

Lao, Dabao; Zhou, Weihu; Ji, Rongyi; Dong, Dengfeng; Xiong, Zhi; Wei, Jiang

2018-01-01

In the case of industrial field measurement, the present measuring instruments work with manual operation and collimation, which give rise to low efficiency for field measurement. In order to solve the problem, a new type industrial total station is presented in this paper. The new instrument can identify and trace cooperative target automatically, in the mean time, coordinate of the target is measured in real time. For realizing the system, key technology including high precision absolutely distance measurement, small high accuracy angle measurement, target automatic collimation with vision, and quick precise controlling should be worked out. After customized system assemblage and adjustment, the new type industrial total station will be established. As the experiments demonstrated, the coordinate accuracy of the instrument is under 15ppm in the distance of 60m, which proved that the measuring system is feasible. The result showed that the total station can satisfy most industrial field measurement requirements.

High-speed rangefinder for industrial application

NASA Astrophysics Data System (ADS)

Cavedo, Federico; Pesatori, Alessandro; Norgia, Michele

2016-06-01

The proposed work aims to improve one of the most used telemetry techniques to make absolute measurements of distance: the time of flight telemetry. The main limitation of the low-cost implementation of this technique is the low accuracy (some mm) and measurement rate (few measurements per second). In order to overcome these limits we modified the typical setup of this rangefinder exploiting low-cost telecommunication transceivers and radiofrequency synthesizers. The obtained performances are very encouraging, reaching a standard deviation of a few micrometers over the range of some meters.

Theory of Maxwell's fish eye with mutually interacting sources and drains

NASA Astrophysics Data System (ADS)

Leonhardt, Ulf; Sahebdivan, Sahar

2015-11-01

Maxwell's fish eye is predicted to image with a resolution not limited by the wavelength of light. However, interactions between sources and drains may ruin the subwavelength imaging capabilities of this and similar absolute optical instruments. Nevertheless, as we show in this paper, at resonance frequencies of the device, an array of drains may resolve a single source, or alternatively, a single drain may scan an array of sources, no matter how narrowly spaced they are. It seems that near-field information can be obtained from far-field distances.

Eddy current measurement of tube element spacing

DOEpatents

Latham, Wayne Meredith; Hancock, Jimmy Wade; Grut, Jayne Marie

1998-01-01

A method of electromagnetically measuring the distance between adjacent tube elements in a heat exchanger. A cylindrical, high magnetic permeability ferrite slug is placed in the tube adjacent the spacing to be measured. A bobbin or annular coil type probe operated in the absolute mode is inserted into a second tube adjacent the spacing to be measured. From prior calibrations on the response of the eddy current coil, the signals from the coil, when sensing the presence of the ferrite slug, are used to determine the spacing between the tubes.

Ice in space: An experimental and theoretical investigation

NASA Technical Reports Server (NTRS)

Patashnick, H.; Rupprecht, G.

1977-01-01

Basic knowledge is provided on the behavior of ice and ice particles under a wide variety of conditions including those of interplanetary space. This information and, in particular, the lifetime of ice particles as a function of solar distance is an absolute requirement for a proper interpretation of photometric profiles in comets. Because fundamental properties of ice and ice particles are developed in this report, the applicability of this information extends beyond the realm of comets into any area where volatile particles exist, be it in space or in the earth's atmosphere.

Low-Cost Ultrasonic Distance Sensor Arrays with Networked Error Correction

PubMed Central

Dai, Hongjun; Zhao, Shulin; Jia, Zhiping; Chen, Tianzhou

2013-01-01

Distance has been one of the basic factors in manufacturing and control fields, and ultrasonic distance sensors have been widely used as a low-cost measuring tool. However, the propagation of ultrasonic waves is greatly affected by environmental factors such as temperature, humidity and atmospheric pressure. In order to solve the problem of inaccurate measurement, which is significant within industry, this paper presents a novel ultrasonic distance sensor model using networked error correction (NEC) trained on experimental data. This is more accurate than other existing approaches because it uses information from indirect association with neighboring sensors, which has not been considered before. The NEC technique, focusing on optimization of the relationship of the topological structure of sensor arrays, is implemented for the compensation of erroneous measurements caused by the environment. We apply the maximum likelihood method to determine the optimal fusion data set and use a neighbor discovery algorithm to identify neighbor nodes at the top speed. Furthermore, we adopt the NEC optimization algorithm, which takes full advantage of the correlation coefficients for neighbor sensors. The experimental results demonstrate that the ranging errors of the NEC system are within 2.20%; furthermore, the mean absolute percentage error is reduced to 0.01% after three iterations of this method, which means that the proposed method performs extremely well. The optimized method of distance measurement we propose, with the capability of NEC, would bring a significant advantage for intelligent industrial automation. PMID:24013491

Surgical treatment of middle aortic syndrome with Takayasu arteritis or midaortic dysplastic syndrome.

PubMed

Kim, S M; Jung, I M; Han, A; Min, S-I; Lee, T; Ha, J; Kim, S J; Min, S-K

2015-08-01

Middle aortic syndrome (MAS) is a rare condition characterized by severe stenosis of the distal thoracic or abdominal aorta. The aims of this study are to define the anatomic characteristics of MAS and to review the various surgical methods and their outcomes in terms of long-term durability Ten adult patients were diagnosed with MAS caused by Takayasu arteritis (TA) or midaortic dysplastic syndrome and underwent surgical treatment between July 1992 and January 2013. The aortic lesions were mostly suprarenal (n = 7) and stenoses were commonly found in the celiac axis (n = 6), SMA (n = 7), and renal artery (n = 6). Indications for operation were uncontrolled hypertension in six patients and lower extremity claudication in four. Eight aortic bypasses, one supraceliac aortic interposition graft, and one bilateral aorto-renal bypass were performed. Adjunctive renal bypass with saphenous vein graft (n = 4) and IMA reimplantation (n = 2) were performed simultaneously. There was no post-operative mortality, and one complication of iliac dissection at the distal anastomosis site was detected and treated by stenting. Hypertension was cured or improved in five of the six patients, and lower extremity claudication improved in all of them. With a median follow up of 60 months (range, 12-263), all the aortic bypasses were patent and one adjunctive renal artery bypass graft with aortic bypass was occluded 29 months post-operatively. Aortic bypass for MAS is safe and shows excellent long-term durability. Considering the patients are relatively young with a long life expectancy, aggressive surgical treatment could be beneficial. Lifelong follow up to monitor complications and disease progression is necessary. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Prognostic impact of subclinical or manifest extracoronary artery diseases after acute myocardial infarction.

PubMed

Eriksson Östman, Maja; Calais, Fredrik; Rosenblad, Andreas; Fröbert, Ole; Leppert, Jerzy; Hedberg, Pär

2017-08-01

In patients with coronary artery disease (CAD), clinically overt extracoronary artery diseases (ECADs), including claudication or previous strokes, are associated with poor outcomes. Subclinical ECADs detected by screening are common among such patients. We aimed to evaluate the prognostic impact of subclinical versus symptomatic ECADs in patients with acute myocardial infarction (AMI). In a prospective observational study, 654 consecutive patients diagnosed with AMI underwent ankle brachial index (ABI) measurements and ultrasonographic screening of the carotid arteries and abdominal aorta. Clinical ECADs were defined as prior strokes, claudication, or extracoronary artery intervention. Subclinical ECADs were defined as the absence of a clinical ECAD in combination with an ABI ≤0.9 or >1.4, carotid artery stenosis, or an abdominal aortic aneurysm. At baseline, subclinical and clinical ECADs were prevalent in 21.6% and 14.4% of the patients, respectively. Patients with ECADs received evidence-based medication more often at admission but similar medications at discharge compared with patients without ECADs. During a median follow-up of 5.2 years, 166 patients experienced endpoints of hospitalization for AMI, heart failure, stroke, or cardiovascular death. With ECAD-free cases as reference and after adjustment for risk factors, a clinical ECAD (hazard ratio [HR] 2.10, 95% confidence interval [CI] 1.34-3.27, p=0.001), but not a subclinical ECAD (HR 1.35, 95% CI 0.89-2.05, p=0.164), was significantly associated with worse outcomes. Despite receiving similar evidence-based medication at discharge, patients with clinical ECAD, but not patients with a subclinical ECAD, had worse long-term prognosis than patients without an ECAD after AMI. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Spondylectomy and lateral lumbar interbody fusion for thoracolumbar kyphosis in an adult with achondroplasia: A case report.

PubMed

Miyazaki, Masashi; Kanezaki, Shozo; Notani, Naoki; Ishihara, Toshinobu; Tsumura, Hiroshi

2017-12-01

Fixed thoracolumbar kyphosis with spinal stenosis in adult patients with achondroplasia presents a challenging issue. We describe the first case in which spondylectomy and minimally invasive lateral access interbody arthrodesis were used for the treatment of fixed severe thoracolumbar kyphosis and lumbar spinal canal stenosis in an adult with achondroplasia. A 61-year-old man with a history of achondroplastic dwarfism presented with low back pain and radiculopathy and neurogenic claudication. Plain radiographs revealed a high-grade thoracolumbar kyphotic deformity with diffuse degenerative changes in the lumbar spine. The apex was located at L2, the local kyphotic angle from L1 to L3 was 105°, and the anterior area was fused from the L1 to L3 vertebrae. MRI revealed significant canal and lateral recess stenosis secondary to facet hypertrophy. We planned a front-back correction of the anterior and posterior spinal elements. We first performed anterior release at the fused part from L1 to L3 and XLIF at L3/4 and L4/5. Next, the patient was placed in the prone position. Spondylectomy at the L2 vertebra and posterior fusion from T10 to L5 were performed. Postoperative radiographs revealed L1 to L3 kyphosis of 32°. No complications occurred during or after surgery. Postoperatively, the patient's low back pain and neurological claudication were resolved. No worsening of kyphosis was observed 24 months postoperatively. Circumferential decompression of the spinal cord at the apical vertebral level and decompression of lumbar canal stenosis were necessary. Front-back correction of the anterior and posterior spinal elements via spondylectomy and lateral lumbar interbody fusion is a reasonable surgical option for thoracolumbar kyphosis and developmental canal stenosis in patients with achondroplasia.

Spinal case of the month with short perspective: How would you treat this L3-L4 synovial cyst?

PubMed

Epstein, Nancy E

2018-01-01

In this new section, Case of the Month with Short Perspective from Surgical Neurology International, we want to see how various spine surgeons would approach different spinal pathologies. In this first case, an elderly male presented with 3 years of lower back pain and progressive neurogenic claudication with bilateral radiculopathy that had exacerbated over the prior 6 months. An outside physician performed a magnetic resonance (MR) study of the lumbar spine that showed a massive synovial cyst filling the spinal canal (e.g., large bilateral cysts) at the L3-L4 level with grade I spondylolisthesis. The MR and CT studies also both demonstrated moderate L2-L3, and severe L3-L4 stenosis. Despite the massive synovial cyst filling the spinal canal at the L3-L4 level, pain management (anesthesia training) spent 3 months performing three successive epidural steroid injections accompanied by attempts at percutaneous synovial cyst aspiration/rupture. By the time the patient presented to neurosurgery, he had developed severe neurogenic claudication, radiculopathy, myelopathy, and a cauda equina syndrome. Dynamic X-rays revealed a mild grade I degenerative spondylolisthesis at the L3-L4 level without active motion, while both computed tomography (CT) and MR studies confirmed moderate stenosis stenosis/ossification of the yellow ligament at the L2-L3 level, severe stenosis at L3-L4 level with spondylolisthesis, and massive bilateral synovial cysts at the L3-L4 level filling the spinal canal. Following an L2-L4 decompressive laminectomy without fusion (note the absence of motion intraoperatively at the L3-L4 level), the patient's symptoms resolved, and he regained normal function. How would you have managed this patient?

Introducing the Concept of the Minimally Important Difference to Determine a Clinically Relevant Change on Patient-Reported Outcome Measures in Patients with Intermittent Claudication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conijn, Anne P., E-mail: a.p.conijn@amc.nl; Jonkers, Wilma, E-mail: wilma.jonkers@achmea.nl; Rouwet, Ellen V., E-mail: e.rouwet@erasmusmc.nl

PurposeThe minimally important difference (MID) represents the smallest change in score on patient-reported outcome measures that is relevant to patients. The aim of this study was to introduce the MID for the Vascular Quality of Life Questionnaire (VascuQol) and the walking impairment questionnaire (WIQ) for patients with intermittent claudication (IC).MethodsIn this multicenter study, we recruited 294 patients with IC between July and October 2012. Patients completed the VascuQol, with scores ranging from 1 to 7 (worst to best), and the WIQ, with scores ranging from 0 to 1 (worst to best) at first visit and after 4 months follow-up. Inmore » addition, patients answered an anchor-question rating their health status compared to baseline, as being improved, unchanged, or deteriorated. The MID for improvement and deterioration was calculated by an anchor-based approach, and determined with the upper and lower limits of the 95 % confidence interval of the mean change of the group who had not changed according to the anchor-question.ResultsFor the MID analyses of the VascuQol and WIQ, 163 and 134 patients were included, respectively. The MID values for the VascuQol (mean baseline score 4.25) were 0.87 for improvement and 0.23 for deterioration. For the WIQ (mean baseline score 0.39), we found MID values of 0.11 and −0.03 for improvement and deterioration, respectively.ConclusionIn this study, we calculated the MID for the VascuQol and the WIQ. Applying these MID facilitates better interpretation of treatment outcomes and can help to set treatment goals for individual care.« less

Bias in benefit-risk appraisal in older products: the case of buflomedil for intermittent claudication.

PubMed

De Backer, Tine L M; Vander Stichele, Robert H; Van Bortel, Luc M

2009-01-01

Benefit-risk assessment should be ongoing during the life cycle of a pharmaceutical agent. New products are subjected to rigorous registration laws and rules, which attempt to assure the availability and validity of evidence. For older products, bias in benefit-risk assessment is more likely, as a number of safeguards were not in place at the time these products were registered. This issue of bias in benefit-risk assessment of older products is illustrated here with an example: buflomedil in intermittent claudication. Data on efficacy were retrieved from a Cochrane systematic review. Data on safety were obtained by comparing the number of reports of serious adverse events and fatalities published in the literature with those reported in postmarketing surveillance databases. In the case of efficacy, the slim basis of evidence for the benefit of buflomedil is undermined by documented publication bias. In the case of safety, bias in reporting to international safety databases is illustrated by the discrepancy between the number of drug-related deaths published in the literature (20), the potentially drug-related deaths in the WHO database (20) and deaths attributed to buflomedil in the database of the international marketing authorization holder (11). In older products, efficacy cannot be evaluated without a thorough search for publication bias. For safety, case reporting of drug-related serious events and deaths in the literature remains a necessary instrument for risk appraisal of older medicines, despite the existence of postmarketing safety databases. The enforcement of efficient communication between healthcare workers, drug companies, national centres of pharmacovigilance, national poison centers and the WHO is necessary to ensure the validity of postmarketing surveillance reporting systems. Drugs considered obsolete because of unfavourable benefit-risk assessment should not be allowed to stay on the market.

Long-term results with percutaneous interspinous process devices in the treatment of neurogenic intermittent claudication.

PubMed

Fransen, Patrick

2017-12-01

Neurogenic intermittent claudication (NIC) is the main symptom of degenerative lumbar spinal stenosis. Percutaneous interspinous process decompression devices (IPDs) have been designed as an alternative therapy to conservative treatment and to open decompressive surgery for patients suffering from NIC. Initial short-term results were encouraging. We present the long-term results of a group of patients that we followed to provide insight on long-term outcomes and effectiveness of this technique compared to other decompression methods. Fifteen patients operated for NIC by implantation of percutaneous IPDs have been prospectively monitored for reoperations or complications. Follow-up (FU) was interrupted if the patient was reoperated. Results were considered poor if the patient had to be reoperated at any stage of the FU or if the treatment failed to alleviate the pain after 6 months. Results were considered average if the patient still suffered some pain but did not require reoperation. The patients were followed up to 7 years after the initial surgery. The mean length of the FU was 3.53 years and all patients could be followed. At the end of the FU, the results were good in only 20.0% (3/15), average in 13.3% (2/15) and poor in 66.7% (10/15). Despite initial satisfactory results, long-term FU is disappointing, with 80% poor or average results. The long-term reoperation rate is high (66.6%), increases over time and is higher than after implantation of IPDs for decompression augmentation. Although this technique is simple and safe, its effectiveness seems short-lived. We recommend cautious use and informing patients about the risk of relatively early failure and recurrence.

Pain threshold is achieved at intensity above anaerobic threshold in patients with intermittent claudication.

PubMed

Ritti-Dias, Raphael Mendes; de Moraes Forjaz, Cláudia Lúcia; Cucato, Gabriel Grizzo; Costa, Luis Augusto Riani; Wolosker, Nelson; de Fátima Nunes Marucci, Maria

2009-01-01

Walking training is considered as the first treatment option for patients with peripheral arterial disease and intermittent claudication (IC). Walking exercise has been prescribed for these patients by relative intensity of peak oxygen uptake (VO2peak), ranging from 40% to 70% VO2peak, or pain threshold (PT). However, the relationship between these methods and anaerobic threshold (AT), which is considered one of the best metabolic markers for establishing training intensity, has not been analyzed. Thus, the aim of this study was to compare, in IC patients, the physiological responses at exercise intensities usually prescribed for training (% VO2peak or % PT) with the ones observed at AT. Thirty-three IC patients performed maximal graded cardiopulmonary treadmill test to assess exercise tolerance. During the test, heart rate (HR), VO2, and systolic blood pressure were measured and responses were analyzed at the following: 40% of VO2peak; 70% of VO2peak; AT; and PT. Heart rate and VO2 at 40% and 70% of VO2peak were lower than those at AT (HR: -13 +/- 9% and -3 +/- 8%, P < .01, respectively; VO2: -52 +/- 12% and -13 +/- 15%, P < .01, respectively). Conversely, HR and VO2 at PT were slightly higher than those at AT (HR: +3 +/- 8%, P < .01; VO2: +6 +/- 15%, P = .04). None of the patients achieved the respiratory compensation point. Prescribing exercise for IC patients between 40% and 70% of VO2peak will induce a lower stimulus than that at AT, whereas prescribing exercise at PT will result in a stimulus above AT. Thus, prescribing exercise training for IC patients on the basis of PT will probably produce a greater metabolic stimulus, promoting better cardiovascular benefits.

Patterns and determinants of use of pharmacological therapies for intermittent claudication in PAD outpatients: results of the IDOMENEO study.

PubMed

Cimminiello, Claudio; Polo Friz, Hernan; Marano, Giuseppe; Arpaia, Guido; Boracchi, Patrizia; Spezzigu, Gabriella; Visonà, Adriana

2017-06-01

Peripheral arterial disease (PAD) usually presents with intermittent claudication (IC). The aim of the present study was to assess, in clinical practice, the pattern of use of pharmacological therapies for IC in stable PAD outpatients. A propensity analysis was performed using data from the IDOMENEO study, an observational prospective multicenter cohort study. The association between any pharmacological symptomatic IC therapy with different variables was investigated using generalized linear mixed models with pharmacological therapy as response variable and binomial error. Study population: 213 patients, male sex 147 (69.0%), mean age 70.0±8.6 years. Only 36.6% was under pharmacological treatment for IC, being cilostazol the most used medication (21.6%). Univariate analysis showed a probability of a patient of being assigned to any pharmacological symptomatic IC therapy of 67.0% when Ankle-Brachial Index (ABI) <0.6 and 29.8% when ABI>0.6 (P=0.0048), and a propensity to avoid pharmacological treatment for patients with a high number of drugs to treat cardiovascular risk factors (probability of 55.2% for <4 drugs and 19.6% for >4 drugs, P=0.0317). Multivariate analysis confirmed a higher probability of assigning treatment for ABI<0.6 (P=0.0274), and a trend to a lower probability in patients under polypharmacy (>4 drugs: OR=0.13, P=0.0546). In clinical practice, only one third of stable outpatients with IC used symptomatic pharmacological therapy for IC. We found a propensity of clinicians to assign any symptomatic pharmacological IC therapy to patients with lower values of ABI and a propensity to avoid this kind of treatment in patients under polypharmacy.

Supervised Exercise Therapy for Intermittent Claudication Is Increasingly Endorsed by Dutch Vascular Surgeons.

PubMed

Hageman, David; Lauret, Gert-Jan; Gommans, Lindy N M; Koelemay, Mark J W; van Sambeek, Marc R H M; Scheltinga, Marc R M; Teijink, Joep A W

2018-02-01

Although supervised exercise therapy (SET) is generally accepted as an effective noninvasive treatment for intermittent claudication (IC), Dutch vascular surgeons were initially somewhat hesitant as reported by a 2011 questionnaire study. Later on, a nationwide multidisciplinary network for SET was introduced in the Netherlands. The aim of this questionnaire study was to determine possible trends in conceptions among Dutch vascular surgeons regarding the prescription of SET. In the year of 2015, Dutch vascular surgeons, fellows, and senior residents were asked to complete a 26-item questionnaire including issues that were considered relevant for prescribing SET such as patient selection criteria and comorbidity. Outcome was compared to the 2011 survey. Data of 124 respondents (82% males; mean age 46 years; 64% response rate) were analyzed. SET referral rate of new IC patients was not different over time (2015: 81% vs. 2011: 75%; P = 0.295). However, respondents were more willing to prescribe SET in IC patients with chronic obstructive pulmonary disease (2015: 86% vs. 2011: 69%; P = 0.002). Nevertheless, a smaller portion of respondents found that SET was also indicated for aortoiliac disease (2015: 63% vs. 2011: 76%; P = 0.049). Insufficient health insurance coverage and/or personal financial resources were the most important presumed barriers preventing patients from initiating SET (80% of respondents). Moreover, 94% of respondents judged that SET should be fully reimbursed by all Dutch basic health insurances. The concept of SET for IC is nowadays generally embraced by the vast majority of Dutch vascular surgeons. SET may have gained in popularity in IC patients with cardiopulmonary comorbidity. However, SET remains underutilized for aortoiliac disease. Reimbursement is considered crucial for a successful SET implementation. Copyright © 2017 Elsevier Inc. All rights reserved.

Pnicogen bonded complexes of PO2X (X = F, Cl) with nitrogen bases.

PubMed

Alkorta, Ibon; Elguero, José; Del Bene, Janet E

2013-10-10

An ab initio MP2/aug'-cc-pVTZ study has been carried out on complexes formed between PO2X (X = F and Cl) as the Lewis acids and a series of nitrogen bases ZN, including NH3, H2C═NH, NH2F, NP, NCH, NCF, NF3, and N2. Binding energies of these complexes vary from -10 to -150 kJ/mol, and P-N distances from 1.88 to 2.72 Å. Complexes ZN:PO2F have stronger P(...)N bonds and shorter P-N distances than the corresponding complexes ZN:PO2Cl. Charge transfer from the N lone pair through the π-hole to the P-X and P-O σ* orbitals leads to stabilization of these complexes, although charge-transfer energies can be evaluated only for complexes with binding energies less than -71 kJ/mol. Complexation of PO2X with the strongest bases leads to P···N bonds with a significant degree of covalency, and P-N distances that approach the P-N distances in the molecules PO2NC and PO2NH2. In these complexes, the PO2X molecules distort from planarity. Changes in (31)P absolute chemical shieldings upon complexation do not correlate with changes in charges on P, although they do correlate with the binding energies of the complexes. EOM-CCSD spin-spin coupling constants (1p)J(P-N) are dominated by the Fermi-contact term, which is an excellent approximation to total J. (1p)J(P-N) values are small at long distances, increase as the distance decreases, but then decrease at short P-N distances. At the shortest distances, values of (1p)J(P-N) approach (1)J(P-N) for the molecules PO2NC and PO2NH2.

Supervised exercise therapy versus home-based exercise therapy versus walking advice for intermittent claudication.

PubMed

Hageman, David; Fokkenrood, Hugo Jp; Gommans, Lindy Nm; van den Houten, Marijn Ml; Teijink, Joep Aw

2018-04-06

Although supervised exercise therapy (SET) provides significant symptomatic benefit for patients with intermittent claudication (IC), it remains an underutilized tool. Widespread implementation of SET is restricted by lack of facilities and funding. Structured home-based exercise therapy (HBET) with an observation component (e.g., exercise logbooks, pedometers) and just walking advice (WA) are alternatives to SET. This is the second update of a review first published in 2006. The primary objective was to provide an accurate overview of studies evaluating effects of SET programs, HBET programs, and WA on maximal treadmill walking distance or time (MWD/T) for patients with IC. Secondary objectives were to evaluate effects of SET, HBET, and WA on pain-free treadmill walking distance or time (PFWD/T), quality of life, and self-reported functional impairment. The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register (December 16, 2016) and the Cochrane Central Register of Controlled Trials (2016, Issue 11). We searched the reference lists of relevant studies identified through searches for other potential trials. We applied no restriction on language of publication. We included parallel-group randomized controlled trials comparing SET programs with HBET programs and WA in participants with IC. We excluded studies in which control groups did not receive exercise or walking advice (maintained normal physical activity). We also excluded studies comparing exercise with percutaneous transluminal angioplasty, bypass surgery, or drug therapy. Three review authors (DH, HF, and LG) independently selected trials, extracted data, and assessed trials for risk of bias. Two other review authors (MvdH and JT) confirmed the suitability and methodological quality of trials. For all continuous outcomes, we extracted the number of participants, mean outcome, and standard deviation for each treatment group through the follow-up period, if available. We extracted Medical Outcomes Study Short Form 36 outcomes to assess quality of life, and Walking Impairment Questionnaire outcomes to assess self-reported functional impairment. As investigators used different scales to present results of walking distance and time, we standardized reported data to effect sizes to enable calculation of an overall standardized mean difference (SMD). We obtained summary estimates for all outcome measures using a random-effects model. We assessed the quality of evidence using the GRADE approach. For this update, we included seven additional studies, making a total of 21 included studies, which involved a total of 1400 participants: 635 received SET, 320 received HBET, and 445 received WA. In general, SET and HBET programs consisted of three exercise sessions per week. Follow-up ranged from six weeks to two years. Most trials used a treadmill walking test to investigate effects of exercise therapy on walking capacity. However, two trials assessed only quality of life, functional impairment, and/or walking behavior (i.e., daily steps measured by pedometer). The overall methodological quality of included trials was moderate to good. However, some trials were small with respect to numbers of participants, ranging from 20 to 304.SET groups showed clear improvement in MWD/T compared with HBET and WA groups, with overall SMDs at three months of 0.37 (95% confidence interval [CI] 0.12 to 0.62; P = 0.004; moderate-quality evidence) and 0.80 (95% CI 0.53 to 1.07; P < 0.00001; high-quality evidence), respectively. This translates to differences in increased MWD of approximately 120 and 210 meters in favor of SET groups. Data show improvements for up to six and 12 months, respectively. The HBET group did not show improvement in MWD/T compared with the WA group (SMD 0.30, 95% CI -0.45 to 1.05; P = 0.43; moderate-quality evidence).Compared with HBET, SET was more beneficial for PFWD/T but had no effect on quality of life parameters nor on self-reported functional impairment. Compared with WA, SET was more beneficial for PFWD/T and self-reported functional impairment, as well as for some quality of life parameters (e.g., physical functioning, pain, and physical component summary after 12 months), and HBET had no effect.Data show no obvious effects on mortality rates. Thirteen of the 1400 participants died, but no deaths were related to exercise therapy. Overall, adherence to SET was approximately 80%, which was similar to that reported with HBET. Only limited adherence data were available for WA groups. Evidence of moderate and high quality shows that SET provides an important benefit for treadmill-measured walking distance (MWD and PFWD) compared with HBET and WA, respectively. Although its clinical relevance has not been definitively demonstrated, this benefit translates to increased MWD of 120 and 210 meters after three months in SET groups. These increased walking distances are likely to have a positive impact on the lives of patients with IC. Data provide no clear evidence of a difference between HBET and WA. Trials show no clear differences in quality of life parameters nor in self-reported functional impairment between SET and HBET. However, evidence is of low and very low quality, respectively. Investigators detected some improvements in quality of life favoring SET over WA, but analyses were limited by small numbers of studies and participants. Future studies should focus on disease-specific quality of life and other functional outcomes, such as walking behavior and physical activity, as well as on long-term follow-up.

SU-F-T-307: Peripheral Dose Comparison Between Static and Dynamic Jaw Tracking On a High Definition MLC System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perez-Andujar, A; Cheung, J; Chuang, C

Purpose: To investigate the effect of dynamic and static jaw tracking on patient peripheral doses. Materials and Methods: A patient plan with a large sacral metastasis (volume 800cm3, prescription 600cGyx5) was selected for this study. The plan was created using 2-field RapidArc with jaw tracking enabled (Eclipse, V11.0.31). These fields were then exported and edited in MATLAB with static jaw positions using the control point with the largest field size for each respective arc, but preserving the optimized leaf sequences for delivery. These fields were imported back into Eclipse for dose calculation and comparison and copied to a Rando phantommore » for delivery analysis. Points were chosen in the phantom at depth and on the phantom surface at locations outside the primary radiation field, at distances of 12cm, 20cm, and 30cm from the isocenter. Measurements were acquired with OSLDs placed at these positions in the phantom with both the dynamic and static jaw deliveries for comparison. Surface measurements included an additional 1cm bolus over the OSLDs to ensure electron equilibrium. Results: The static jaw deliveries resulted in cumulative jaw-defined field sizes of 17.3% and 17.4% greater area than the dynamic jaw deliveries for each arc. The static jaw plan resulted in very small differences in calculated dose in the treatment planning system ranging from 0–16cGy. The measured dose differences were larger than calculated, but the differences in absolute dose were small. The measured dose differences at depth (surface) between the two deliveries showed an increase for the static jaw delivery of 2.2%(11.4%), 15.6%(20.0%), and 12.7%(12.7%) for distances of 12cm, 20cm, and 30cm, respectively. Eclipse calculates a difference of 0–3.1% for all of these points. The largest absolute dose difference between all points was 6.2cGy. Conclusion: While we demonstrated larger than expected differences in peripheral dose, the absolute dose differences were small.« less

Reproducibility of visual acuity assessment in normal and low visual acuity.

PubMed

Becker, Ralph; Teichler, Gunnar; Gräf, Michael

2007-01-01

To assess the reproducibility of measurements of visual acuity in both the upper and lower range of visual acuity. The retroilluminated ETDRS 1 and ETDRS 2 charts (Precision Vision) were used for measurement of visual acuity. Both charts use the same letters. The sequence of the charts followed a pseudorandomized protocol. The examination distance was 4.0 m. When the visual acuity was below 0.16 or 0.03, then the examination distance was reduced to 1 m or 0.4 m, respectively, using an appropriate near correction. Visual acuity measurements obtained during the same session with both charts were compared. A total of 100 patients (age 8-90 years; median 60.5) with various eye disorders, including 39 with amblyopia due to strabismus, were tested in addition to 13 healthy volunteers (age 18-33 years; median 24). At least 3 out of 5 optotypes per line had to be correctly identified to pass this line. Wrong answers were monitored. The interpolated logMAR score was calculated. In the patients, the eye with the lower visual acuity was assessed, and for the healthy subjects the right eye. Differences between ETDRS 1 and ETDRS 2-acuity were compared. The mean logMAR values for ETDRS 1 and ETDRS 2 were -0.17 and -0.14 in the healthy eyes and 0.55 and 0.57 in the entire group. The absolute difference between ETDRS 1 and ETDRS 2 was (mean +/- standard deviation) 0.051 +/- 0.04 for the healthy eyes and 0.063 +/- 0.05 in the entire group. In the acuity range below 0.1 (logMAR > 1.0), the absolute difference (mean +/- standard deviation) between ETDRS 1 and ETDRS 2 of 0.072 +/- 0.04 did not significantly exceed the mean absolute difference in healthy eyes (p = 0.17). Regression analysis (|ETDRS 1 - ETDRS 2| vs. ETDRS 1) showed a slight increase of the difference between the two values with lower visual acuity (p = 0.0505; r = 0.18). Assuming correct measurement, the reproducibilty of visual acuity measurements in the lower acuity range is not significantly worse than in normals.

Density-dependent nest predation in waterfowl: the relative importance of nest density versus nest dispersion

USGS Publications Warehouse

Ackerman, Joshua T.; Ringelman, Kevin M.; Eadie, J.M.

2012-01-01

When nest predation levels are very high or very low, the absolute range of observable nest success is constrained (a floor/ceiling effect), and it may be more difficult to detect density-dependent nest predation. Density-dependent nest predation may be more detectable in years with moderate predation rates, simply because there can be a greater absolute difference in nest success between sites. To test this, we replicated a predation experiment 10 years after the original study, using both natural and artificial nests, comparing a year when overall rates of nest predation were high (2000) to a year with moderate nest predation (2010). We found no evidence for density-dependent predation on artificial nests in either year, indicating that nest predation is not density-dependent at the spatial scale of our experimental replicates (1-ha patches). Using nearest-neighbor distances as a measure of nest dispersion, we also found little evidence for “dispersion-dependent” predation on artificial nests. However, when we tested for dispersion-dependent predation using natural nests, we found that nest survival increased with shorter nearest-neighbor distances, and that neighboring nests were more likely to share the same nest fate than non-adjacent nests. Thus, at small spatial scales, density-dependence appears to operate in the opposite direction as predicted: closer nearest neighbors are more likely to be successful. We suggest that local nest dispersion, rather than larger-scale measures of nest density per se, may play a more important role in density-dependent nest predation.

Segmentation of the lumen and media-adventitia boundaries of the common carotid artery from 3D ultrasound images

NASA Astrophysics Data System (ADS)

Ukwatta, E.; Awad, J.; Ward, A. D.; Samarabandu, J.; Krasinski, A.; Parraga, G.; Fenster, A.

2011-03-01

Three-dimensional ultrasound (3D US) vessel wall volume (VWV) measurements provide high measurement sensitivity and reproducibility for the monitoring and assessment of carotid atherosclerosis. In this paper, we describe a semiautomated approach based on the level set method to delineate the media-adventitia and lumen boundaries of the common carotid artery from 3D US images to support the computation of VWV. Due to the presence of plaque and US image artifacts, the carotid arteries are challenging to segment using image information alone. Our segmentation framework combines several image cues with domain knowledge and limited user interaction. Our method was evaluated with respect to manually outlined boundaries on 430 2D US images extracted from 3D US images of 30 patients who have carotid stenosis of 60% or more. The VWV given by our method differed from that given by manual segmentation by 6.7% +/- 5.0%. For the media-adventitia and lumen segmentations, respectively, our method yielded Dice coefficients of 95.2% +/- 1.6%, 94.3% +/- 2.6%, mean absolute distances of 0.3 +/- 0.1 mm, 0.2 +/- 0.1 mm, maximum absolute distances of 0.8 +/- 0.4 mm, 0.6 +/- 0.3 mm, and volume differences of 4.2% +/- 3.1%, 3.4% +/- 2.6%. The realization of a semi-automated segmentation method will accelerate the translation of 3D carotid US to clinical care for the rapid, non-invasive, and economical monitoring of atherosclerotic disease progression and regression during therapy.

Ultrasound Common Carotid Artery Segmentation Based on Active Shape Model

PubMed Central

Yang, Xin; Jin, Jiaoying; Xu, Mengling; Wu, Huihui; He, Wanji; Yuchi, Ming; Ding, Mingyue

2013-01-01

Carotid atherosclerosis is a major reason of stroke, a leading cause of death and disability. In this paper, a segmentation method based on Active Shape Model (ASM) is developed and evaluated to outline common carotid artery (CCA) for carotid atherosclerosis computer-aided evaluation and diagnosis. The proposed method is used to segment both media-adventitia-boundary (MAB) and lumen-intima-boundary (LIB) on transverse views slices from three-dimensional ultrasound (3D US) images. The data set consists of sixty-eight, 17 × 2 × 2, 3D US volume data acquired from the left and right carotid arteries of seventeen patients (eight treated with 80 mg atorvastatin and nine with placebo), who had carotid stenosis of 60% or more, at baseline and after three months of treatment. Manually outlined boundaries by expert are adopted as the ground truth for evaluation. For the MAB and LIB segmentations, respectively, the algorithm yielded Dice Similarity Coefficient (DSC) of 94.4% ± 3.2% and 92.8% ± 3.3%, mean absolute distances (MAD) of 0.26 ± 0.18 mm and 0.33 ± 0.21 mm, and maximum absolute distances (MAXD) of 0.75 ± 0.46 mm and 0.84 ± 0.39 mm. It took 4.3 ± 0.5 mins to segment single 3D US images, while it took 11.7 ± 1.2 mins for manual segmentation. The method would promote the translation of carotid 3D US to clinical care for the monitoring of the atherosclerotic disease progression and regression. PMID:23533535

Study of multi-functional precision optical measuring system for large scale equipment

NASA Astrophysics Data System (ADS)

Jiang, Wei; Lao, Dabao; Zhou, Weihu; Zhang, Wenying; Jiang, Xingjian; Wang, Yongxi

2017-10-01

The effective application of high performance measurement technology can greatly improve the large-scale equipment manufacturing ability. Therefore, the geometric parameters measurement, such as size, attitude and position, requires the measurement system with high precision, multi-function, portability and other characteristics. However, the existing measuring instruments, such as laser tracker, total station, photogrammetry system, mostly has single function, station moving and other shortcomings. Laser tracker needs to work with cooperative target, but it can hardly meet the requirement of measurement in extreme environment. Total station is mainly used for outdoor surveying and mapping, it is hard to achieve the demand of accuracy in industrial measurement. Photogrammetry system can achieve a wide range of multi-point measurement, but the measuring range is limited and need to repeatedly move station. The paper presents a non-contact opto-electronic measuring instrument, not only it can work by scanning the measurement path but also measuring the cooperative target by tracking measurement. The system is based on some key technologies, such as absolute distance measurement, two-dimensional angle measurement, automatically target recognition and accurate aiming, precision control, assembly of complex mechanical system and multi-functional 3D visualization software. Among them, the absolute distance measurement module ensures measurement with high accuracy, and the twodimensional angle measuring module provides precision angle measurement. The system is suitable for the case of noncontact measurement of large-scale equipment, it can ensure the quality and performance of large-scale equipment throughout the process of manufacturing and improve the manufacturing ability of large-scale and high-end equipment.

Analysis of accuracy in photogrammetric roughness measurements

NASA Astrophysics Data System (ADS)

Olkowicz, Marcin; Dąbrowski, Marcin; Pluymakers, Anne

2017-04-01

Regarding permeability, one of the most important features of shale gas reservoirs is the effective aperture of cracks opened during hydraulic fracturing, both propped and unpropped. In a propped fracture, the aperture is controlled mostly by proppant size and its embedment, and fracture surface roughness only has a minor influence. In contrast, in an unpropped fracture aperture is controlled by the fracture roughness and the wall displacement. To measure fracture surface roughness, we have used the photogrammetric method since it is time- and cost-efficient. To estimate the accuracy of this method we compare the photogrammetric measurements with reference measurements taken with a White Light Interferometer (WLI). Our photogrammetric setup is based on high resolution 50 Mpx camera combined with a focus stacking technique. The first step for photogrammetric measurements is to determine the optimal camera positions and lighting. We compare multiple scans of one sample, taken with different settings of lighting and camera positions, with the reference WLI measurement. The second step is to perform measurements of all studied fractures with the parameters that produced the best results in the first step. To compare photogrammetric and WLI measurements we regrid both data sets onto a regular 10 μm grid and determined the best fit, followed by a calculation of the difference between the measurements. The first results of the comparison show that for 90 % of measured points the absolute vertical distance between WLI and photogrammetry is less than 10 μm, while the mean absolute vertical distance is 5 μm. This proves that our setup can be used for fracture roughness measurements in shales.

Exploring the optimum step size for defocus curves.

PubMed

Wolffsohn, James S; Jinabhai, Amit N; Kingsnorth, Alec; Sheppard, Amy L; Naroo, Shehzad A; Shah, Sunil; Buckhurst, Phillip; Hall, Lee A; Young, Graeme

2013-06-01

To evaluate the effect of reducing the number of visual acuity measurements made in a defocus curve on the quality of data quantified. Midland Eye, Solihull, United Kingdom. Evaluation of a technique. Defocus curves were constructed by measuring visual acuity on a distance logMAR letter chart, randomizing the test letters between lens presentations. The lens powers evaluated ranged between +1.50 diopters (D) and -5.00 D in 0.50 D steps, which were also presented in a randomized order. Defocus curves were measured binocularly with the Tecnis diffractive, Rezoom refractive, Lentis rotationally asymmetric segmented (+3.00 D addition [add]), and Finevision trifocal multifocal intraocular lenses (IOLs) implanted bilaterally, and also for the diffractive IOL and refractive or rotationally asymmetric segmented (+3.00 D and +1.50 D adds) multifocal IOLs implanted contralaterally. Relative and absolute range of clear-focus metrics and area metrics were calculated for curves fitted using 0.50 D, 1.00 D, and 1.50 D steps and a near add-specific profile (ie, distance, half the near add, and the full near-add powers). A significant difference in simulated results was found in at least 1 of the relative or absolute range of clear-focus or area metrics for each of the multifocal designs examined when the defocus-curve step size was increased (P<.05). Faster methods of capturing defocus curves from multifocal IOL designs appear to distort the metric results and are therefore not valid. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Segmentation of the common carotid artery with active shape models from 3D ultrasound images

NASA Astrophysics Data System (ADS)

Yang, Xin; Jin, Jiaoying; He, Wanji; Yuchi, Ming; Ding, Mingyue

2012-03-01

Carotid atherosclerosis is a major cause of stroke, a leading cause of death and disability. In this paper, we develop and evaluate a new segmentation method for outlining both lumen and adventitia (inner and outer walls) of common carotid artery (CCA) from three-dimensional ultrasound (3D US) images for carotid atherosclerosis diagnosis and evaluation. The data set consists of sixty-eight, 17× 2× 2, 3D US volume data acquired from the left and right carotid arteries of seventeen patients (eight treated with 80mg atorvastain and nine with placebo), who had carotid stenosis of 60% or more, at baseline and after three months of treatment. We investigate the use of Active Shape Models (ASMs) to segment CCA inner and outer walls after statin therapy. The proposed method was evaluated with respect to expert manually outlined boundaries as a surrogate for ground truth. For the lumen and adventitia segmentations, respectively, the algorithm yielded Dice Similarity Coefficient (DSC) of 93.6%+/- 2.6%, 91.8%+/- 3.5%, mean absolute distances (MAD) of 0.28+/- 0.17mm and 0.34 +/- 0.19mm, maximum absolute distances (MAXD) of 0.87 +/- 0.37mm and 0.74 +/- 0.49mm. The proposed algorithm took 4.4 +/- 0.6min to segment a single 3D US images, compared to 11.7+/-1.2min for manual segmentation. Therefore, the method would promote the translation of carotid 3D US to clinical care for the fast, safety and economical monitoring of the atherosclerotic disease progression and regression during therapy.

Development and Testing of a High-Precision Position and Attitude Measuring System for a Space Mechanism

NASA Technical Reports Server (NTRS)

Khanenya, Nikolay; Paciotti, Gabriel; Forzani, Eugenio; Blecha, Luc

2016-01-01

This paper describes a high-precision optical metrology system - a unique ground test equipment which was designed and implemented for simultaneous precise contactless measurements of 6 degrees-of-freedom (3 translational + 3 rotational) of a space mechanism end-effector [1] in a thermally controlled ISO 5 clean environment. The developed contactless method reconstructs both position and attitude of the specimen from three cross-sections measured by 2D distance sensors [2]. The cleanliness is preserved by the hermetic test chamber filled with high purity nitrogen. The specimen's temperature is controlled by the thermostat [7]. The developed method excludes errors caused by the thermal deformations and manufacturing inaccuracies of the test jig. Tests and simulations show that the measurement accuracy of an object absolute position is of 20 micron in in-plane measurement (XY) and about 50 micron out of plane (Z). The typical absolute attitude is determined with an accuracy better than 3 arcmin in rotation around X and Y and better than 10 arcmin in Z. The metrology system is able to determine relative position and movement with an accuracy one order of magnitude lower than the absolute accuracy. Typical relative displacement measurement accuracies are better than 1 micron in X and Y and about 2 micron in Z. Finally, the relative rotation can be measured with accuracy better than 20 arcsec in any direction.

Bioresorbable Everolimus-Eluting Vascular Scaffold for Patients With Peripheral Artery Disease (ESPRIT I): 2-Year Clinical and Imaging Results.

PubMed

Lammer, Johannes; Bosiers, Marc; Deloose, Koen; Schmidt, Andrej; Zeller, Thomas; Wolf, Florian; Lansink, Wouter; Sauguet, Antoine; Vermassen, Frank; Lauwers, Geert; Scheinert, Dierk; Popma, Jeffrey J; McGreevy, Robert; Rapoza, Richard; Schwartz, Lewis B; Jaff, Michael R

2016-06-13

This is the first-in-human study of a drug-eluting bioresorbable vascular scaffold (BVS) for treatment of peripheral artery disease (PAD) involving the external iliac artery (EIA) and superficial femoral artery (SFA). Drug-eluting BVS has shown promise in coronary arteries. The ESPRIT BVS system is a device-drug combination consisting of an everolimus-eluting poly-l-lactide scaffold. Safety and performance were evaluated in 35 subjects with symptomatic claudication. Lesions were located in the SFA (88.6%) and EIA (11.4%). Mean lesion length was 35.7 ± 16.0 mm. The study device was successfully deployed in 100% of cases, without recoil. Procedure-related minor complications were observed in 3 patients (groin hematoma, dissection). Within 2 years there was 1 unrelated death, but no patients in this cohort had an amputation. At 1 and 2 years, the binary restenosis rates were 12.1% and 16.1%, respectively, and target lesion revascularization was performed in 3 of 34 patients (8.8%) and 4 of 32 patients (11.8%), respectively. The ankle brachial index 0.75 ± 0.14 improved from pre-procedure to 0.96 ± 0.16 at 2 years' follow-up. At 2 years, 71.0% of the patients were Rutherford-Becker 0, and 93.5% achieved a maximum walking distance of 1,500 feet. The safety of the ESPRIT BVS was demonstrated with no procedure or device-related deaths or amputations within 2 years. The low occurrence of revascularizations was consistent with duplex-ultrasonography showing sustained patency at 2-years. (A Clinical Evaluation of the Abbott Vascular ESPRIT BVS [Bioresorbable Vascular Scaffold] System [ESPRIT I]; NCT01468974). Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Propionyl-L-carnitine improves endothelial function, microcirculation and pain management in critical limb ischemia.

PubMed

De Marchi, S; Zecchetto, S; Rigoni, A; Prior, M; Fondrieschi, L; Scuro, A; Rulfo, F; Arosio, E

2012-10-01

Chronic critical limb ischemia (CLI) is a severe condition of hypo-perfusion of lower limbs, which is associated with inflammation and a pro-coagulative state. It is a disease at high risk of amputation and cardiovascular death. Propionyl-L-carnitine (PLC) is efficacious in improving pain free walking distance in peripheral arterial disease with claudication; it also exerts favorable effects on the arterial wall and on endothelial function. The purpose of this study was to evaluate the effects of PLC on microcirculation, endothelial function and pain relief in patients affected by CLI not suitable for surgical intervention. We enrolled 48 patients with CLI. Patients were randomized into two groups: the first group was treated with PLC, the second was treated with saline solution. All of them underwent the following tests: laser Doppler flowmetry at the forefoot at rest and after ischemia, trans cutaneous oxygen partial pressure and carbon dioxide partial pressure at the forefoot at rest and after ischemia, endothelium dependent dilation of the brachial artery. All tests were repeated after treatments. Pain was assessed by visual analog pain scale. Endothelium dependent dilation increased after PLC (9.5 ± 3.2 vs 4.9 ± 1.4 %; p < 0.05). Post-ischemic peak flow with laser-Doppler flow increased after PLC. TcPO2 increased, while TcPCO2 decreased after PLC; CO2 production decreased after PLC. VAS showed a significant reduction in pain perception after active treatment. In CLI patients, PLC can improve microcirculation (post ischemic hyperemia, TcPO2 and TcPCO2 production). PLC also enhances endothelium dependent dilation and reduces analgesic consumption and pain perception.

Takayasu Arteritis in a Young Woman

PubMed Central

Saab, Fadi; Giugliano, Robert P.; Giugliano, Gregory R.

2009-01-01

Takayasu arteritis is a chronic, progressive, autoimmune, idiopathic, large-vessel vasculitis that usually affects young adults. The disease has been reported to occur in all races and ethnicities. The diffuse nature of this vasculitis can affect multiple-organ systems to varying degrees. Herein, we report the case of a young woman whose exertional angina and claudication were the initial presentation of active Takayasu arteritis. During more than 4 years of ongoing treatment, therapy, and follow-up, she has displayed differing disease symptoms of varying intensity. We discuss the challenges of managing Takayasu arteritis in our patient and describe different treatments for this rare vasculitic disorder. PMID:19876432

Bilateral External Iliac Artery Dissection in a Middle-Aged Male Athlete

PubMed Central

Yamanaka, Yasushi; Yoshida, Tetsuya; Nagaoka, Eiki

2017-01-01

We present the case of a bilateral external iliac artery (EIA) dissection in a 44-year-old male athlete. The patient was referred to our department for right lower abdominal pain without claudication during single squatting. His athletic history included participation in approximately five athletic events per year. Contrast-enhanced computed tomography (CT) revealed bilateral EIA dissection and right renal infarction. Following medical treatment for his hypertension and considering his medical history, a bilateral EIA replacement with 8-mm Dacron straight grafts was performed on the 24th day after hospital admission. Postoperative contrast-enhanced CT revealed good bilateral graft patency and perfusion following surgery. PMID:29515713

Bilateral External Iliac Artery Dissection in a Middle-Aged Male Athlete.

PubMed

Yamanaka, Yasushi; Yoshida, Tetsuya; Nagaoka, Eiki

2017-12-25

We present the case of a bilateral external iliac artery (EIA) dissection in a 44-year-old male athlete. The patient was referred to our department for right lower abdominal pain without claudication during single squatting. His athletic history included participation in approximately five athletic events per year. Contrast-enhanced computed tomography (CT) revealed bilateral EIA dissection and right renal infarction. Following medical treatment for his hypertension and considering his medical history, a bilateral EIA replacement with 8-mm Dacron straight grafts was performed on the 24th day after hospital admission. Postoperative contrast-enhanced CT revealed good bilateral graft patency and perfusion following surgery.

Occlusive Disease of the Vessels of the Aortic Arch—Diagnosis and Management

PubMed Central

Johnson, C. Delmar; Zirkle, Thomas J.; Smith, Louis L.

1968-01-01

Physicians should be alert to the possibility of occlusion of one or more of the branches of the aortic arch in any patient having neurologic symptoms or complaint of claudication in the upper extremities. The finding of a pulse deficit in the neck or arm and a blood pressure difference of more than 30 mm of mercury between the two arms is pathognomic of this disease. The presence of the occlusive process can be confirmed and its extent determined by angiography. Vascular reconstruction can be expected to restore normal hemodynamics with gratifying relief of symptoms in the majority of cases. PMID:18730091

Long-range non-contact imaging photoplethysmography: cardiac pulse wave sensing at a distance

NASA Astrophysics Data System (ADS)

Blackford, Ethan B.; Estepp, Justin R.; Piasecki, Alyssa M.; Bowers, Margaret A.; Klosterman, Samantha L.

2016-03-01

Non-contact, imaging photoplethysmography uses photo-optical sensors to measure variations in light absorption, caused by blood volume pulsations, to assess cardiopulmonary parameters including pulse rate, pulse rate variability, and respiration rate. Recently, researchers have studied the applications and methodology of imaging photoplethysmography. Basic research has examined some of the variables affecting data quality and accuracy of imaging photoplethysmography including signal processing, imager parameters (e.g. frame rate and resolution), lighting conditions, subject motion, and subject skin tone. This technology may be beneficial for long term or continuous monitoring where contact measurements may be harmful (e.g. skin sensitivities) or where imperceptible or unobtrusive measurements are desirable. Using previously validated signal processing methods, we examined the effects of imager-to-subject distance on one-minute, windowed estimates of pulse rate. High-resolution video of 22, stationary participants was collected using an enthusiast-grade, mirrorless, digital camera equipped with a fully-manual, super-telephoto lens at distances of 25, 50, and 100 meters with simultaneous contact measurements of electrocardiography, and fingertip photoplethysmography. By comparison, previous studies have usually been conducted with imager-to-subject distances of up to only a few meters. Mean absolute error for one-minute, windowed, pulse rate estimates (compared to those derived from gold-standard electrocardiography) were 2.0, 4.1, and 10.9 beats per minute at distances of 25, 50, and 100 meters, respectively. Long-range imaging presents several unique challenges among which include decreased, observed light reflectance and smaller regions of interest. Nevertheless, these results demonstrate that accurate pulse rate measurements can be obtained from over long imager-to-participant distances given these constraints.

The Next Generation Virgo Cluster Survey (NGVS). XVIII. Measurement and Calibration of Surface Brightness Fluctuation Distances for Bright Galaxies in Virgo (and Beyond)

NASA Astrophysics Data System (ADS)

Cantiello, Michele; Blakeslee, John P.; Ferrarese, Laura; Côté, Patrick; Roediger, Joel C.; Raimondo, Gabriella; Peng, Eric W.; Gwyn, Stephen; Durrell, Patrick R.; Cuillandre, Jean-Charles

2018-04-01

We describe a program to measure surface brightness fluctuation (SBF) distances to galaxies observed in the Next Generation Virgo Cluster Survey (NGVS), a photometric imaging survey covering 104 deg2 of the Virgo cluster in the u*, g, i, and z bandpasses with the Canada–France–Hawaii Telescope. We describe the selection of the sample galaxies, the procedures for measuring the apparent i-band SBF magnitude {\\overline{m}}i, and the calibration of the absolute Mibar as a function of observed stellar population properties. The multiband NGVS data set provides multiple options for calibrating the SBF distances, and we explore various calibrations involving individual color indices as well as combinations of two different colors. Within the color range of the present sample, the two-color calibrations do not significantly improve the scatter with respect to wide-baseline, single-color calibrations involving u*. We adopt the ({u}* -z) calibration as a reference for the present galaxy sample, with an observed scatter of 0.11 mag. For a few cases that lack good u* photometry, we use an alternative relation based on a combination of (g-i) and (g-z) colors, with only a slightly larger observed scatter of 0.12 mag. The agreement of our measurements with the best existing distance estimates provides confidence that our measurements are accurate. We present a preliminary catalog of distances for 89 galaxies brighter than B T ≈ 13.0 mag within the survey footprint, including members of the background M and W Clouds at roughly twice the distance of the main body of the Virgo cluster. The extension of the present work to fainter and bluer galaxies is in progress.

QCD phenomenology of static sources and gluonic excitations at short distances

NASA Astrophysics Data System (ADS)

Bali, Gunnar S.; Pineda, Antonio

2004-05-01

New lattice data for the Πu and Σ-u potentials at short distances are presented. We compare perturbation theory to the lower static hybrid potentials and find good agreement at short distances, once the renormalon ambiguities are accounted for. We use the nonperturbatively determined continuum-limit static hybrid and ground state potentials at short distances to determine the gluelump energies. The result is consistent with an estimate obtained from the gluelump data at finite lattice spacings. For the lightest gluelump, we obtain ΛRSB(νf=2.5r-10)=[2.25±0.10(latt.)±0.21(th.)±0.08(ΛMS¯)]r-10 in the quenched approximation with r-10≈400 MeV. We show that, to quote sensible numbers for the absolute values of the gluelump energies, it is necessary to handle the singularities of the singlet and octet potentials in the Borel plane. We propose to subtract the renormalons of the short-distance matching coefficients, the potentials in this case. For the singlet potential the leading renormalon is already known and related to that of the pole mass; for the octet potential a new renormalon appears, which we approximately evaluate. We also apply our methods to heavy-light mesons in the static limit and from the lattice simulations available in the literature we obtain the quenched result Λ¯RS(νf=2.5r-10)=[1.17±0.08(latt.)±0.13(th.)±0.09(ΛMS¯)]r-10. We calculate mb,MS¯(mb,MS¯) and apply our methods to gluinonia whose dynamics are governed by the singlet potential between adjoint sources. We can exclude nonstandard linear short-distance contributions to the static potentials, with good accuracy.

Pacing and performance in competitive middle-distance speed skating.

PubMed

Muehlbauer, Thomas; Schindler, Christian; Panzer, Stefan

2010-03-01

Data from speed skating during World Cup 1500-m middle-distance races were analyzed to (a) determine the time/velocity distribution during the race and (b) assess the impact of time spent in several race sectors on performance outcome. Absolute and relative sector times for the first 300 m (S1) and the following three 400-m laps (S2-S4) and their associations with total race time were analyzed for 53 female and 61 male skaters. Simple regression analyses revealed that both a short relative sector time later in the race (women in S3: p < .001; men in S3: p = .001) and a high relative sector time early in the race (women in S1: p < .001; men in S1: p = .08) were associated with a short total race time in the 1500-m middle-distance event. These findings suggest that for the best overall time it is important to be as fast as possible later in the race and not quite as fast during the first part of the race. Therefore, speed skating performance may be improved by maintaining a high velocity or by minimizing the decline from a high velocity during later race segments.

ACCELERATION OF COMPACT RADIO JETS ON SUB-PARSEC SCALES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sang-Sung; Lobanov, Andrei P.; Krichbaum, Thomas P.

2016-08-01

Jets of compact radio sources are highly relativistic and Doppler boosted, making studies of their intrinsic properties difficult. Observed brightness temperatures can be used to study the intrinsic physical properties of relativistic jets, and constrain models of jet formation in the inner jet region. We aim to observationally test such inner jet models. The very long baseline interferometry (VLBI) cores of compact radio sources are optically thick at a given frequency. The distance of the core from the central engine is inversely proportional to the frequency. Under the equipartition condition between the magnetic field energy and particle energy densities, themore » absolute distance of the VLBI core can be predicted. We compiled the brightness temperatures of VLBI cores at various radio frequencies of 2, 8, 15, and 86 GHz. We derive the brightness temperature on sub-parsec scales in the rest frame of the compact radio sources. We find that the brightness temperature increases with increasing distance from the central engine, indicating that the intrinsic jet speed (the Lorentz factor) increases along the jet. This implies that the jets are accelerated in the (sub-)parsec regions from the central engine.« less

Honeybee Odometry: Performance in Varying Natural Terrain

PubMed Central

Tautz, Juergen; Zhang, Shaowu; Spaethe, Johannes; Brockmann, Axel; Si, Aung

2004-01-01

Recent studies have shown that honeybees flying through short, narrow tunnels with visually textured walls perform waggle dances that indicate a much greater flight distance than that actually flown. These studies suggest that the bee's “odometer” is driven by the optic flow (image motion) that is experienced during flight. One might therefore expect that, when bees fly to a food source through a varying outdoor landscape, their waggle dances would depend upon the nature of the terrain experienced en route. We trained honeybees to visit feeders positioned along two routes, each 580 m long. One route was exclusively over land. The other was initially over land, then over water and, finally, again over land. Flight over water resulted in a significantly flatter slope of the waggle-duration versus distance regression, compared to flight over land. The mean visual contrast of the scenes was significantly greater over land than over water. The results reveal that, in outdoor flight, the honeybee's odometer does not run at a constant rate; rather, the rate depends upon the properties of the terrain. The bee's perception of distance flown is therefore not absolute, but scene-dependent. These findings raise important and interesting questions about how these animals navigate reliably. PMID:15252454

Automatic Approach for Lung Segmentation with Juxta-Pleural Nodules from Thoracic CT Based on Contour Tracing and Correction.

PubMed

Wang, Jinke; Guo, Haoyan

2016-01-01

This paper presents a fully automatic framework for lung segmentation, in which juxta-pleural nodule problem is brought into strong focus. The proposed scheme consists of three phases: skin boundary detection, rough segmentation of lung contour, and pulmonary parenchyma refinement. Firstly, chest skin boundary is extracted through image aligning, morphology operation, and connective region analysis. Secondly, diagonal-based border tracing is implemented for lung contour segmentation, with maximum cost path algorithm used for separating the left and right lungs. Finally, by arc-based border smoothing and concave-based border correction, the refined pulmonary parenchyma is obtained. The proposed scheme is evaluated on 45 volumes of chest scans, with volume difference (VD) 11.15 ± 69.63 cm 3 , volume overlap error (VOE) 3.5057 ± 1.3719%, average surface distance (ASD) 0.7917 ± 0.2741 mm, root mean square distance (RMSD) 1.6957 ± 0.6568 mm, maximum symmetric absolute surface distance (MSD) 21.3430 ± 8.1743 mm, and average time-cost 2 seconds per image. The preliminary results on accuracy and complexity prove that our scheme is a promising tool for lung segmentation with juxta-pleural nodules.

Ground-motion prediction equations for the average horizontal component of PGA, PGV, and 5%-damped PSA at spectral periods between 0.01 s and 10.0 s

USGS Publications Warehouse

Boore, D.M.; Atkinson, G.M.

2008-01-01

This paper contains ground-motion prediction equations (GMPEs) for average horizontal-component ground motions as a function of earthquake magnitude, distance from source to site, local average shear-wave velocity, and fault type. Our equations are for peak ground acceleration (PGA), peak ground velocity (PGV), and 5%-damped pseudo-absolute-acceleration spectra (PSA) at periods between 0.01 s and 10 s. They were derived by empirical regression of an extensive strong-motion database compiled by the 'PEER NGA' (Pacific Earthquake Engineering Research Center's Next Generation Attenuation) project. For periods less than 1 s, the analysis used 1,574 records from 58 mainshocks in the distance range from 0 km to 400 km (the number of available data decreased as period increased). The primary predictor variables are moment magnitude (M), closest horizontal distance to the surface projection of the fault plane (RJB), and the time-averaged shear-wave velocity from the surface to 30 m (VS30). The equations are applicable for M=5-8, RJB<200 km, and VS30= 180-1300 m/s. ?? 2008, Earthquake Engineering Research Institute.

Combined Dietary Nitrate and Exercise Intervention in Peripheral Artery Disease: Protocol Rationale and Design

PubMed Central

Woessner, Mary N; VanBruggen, Mitch D; Pieper, Carl F; O'Reilly, Erin K; Kraus, William E

2017-01-01

Background Peripheral artery disease (PAD) is caused by atherosclerotic occlusions in the legs. It affects approximately 8-12 million people in the United States alone, one-third of whom suffer from intermittent claudication (IC), defined as ischemic leg pain that occurs with walking and improves with rest. Patients with IC suffer a markedly impaired quality of life and a high perception of disability. Improving pain-free walking time is a primary goal of rehabilitation in this population. Objective The nitric oxide (NO)-PAD trial is designed to compare the effects that 12 weeks of supervised exercise training, in combination with a high inorganic nitrate-content (beetroot [BR] juice) beverage or placebo (PL) beverage, has on clinical outcomes of exercise and functional capacity in two groups of PAD+IC patients: exercise training plus beetroot (EX+BR) and exercise training plus placebo (EX+PL). The primary aims of this randomized controlled, double-blind pilot study are to determine group differences following 12 weeks of EX+BR versus EX+PL in the changes for (1) exercise capacity: pain-free walking time (claudication onset time, COT), peak walk time (PWT), and maximal exercise capacity (peak oxygen uptake, VO2peak) during a maximal-graded cardiopulmonary exercise test (max CPX) and (2) functional capacity: 6-minute walk (6MW) distance. The secondary aims will provide mechanistic insights into the exercise outcome measures and will include (1) gastrocnemius muscle oxygenation during exercise via near-infrared spectroscopy (NIRS); (2) gastrocnemius muscle angiogenesis: capillaries per unit area and per muscle fiber, and relative fraction of type I, IIa, IIb, and IId/x fibers; and (3) vascular health/function via brachial artery flow-mediated dilation, lower-limb blood flow via plethysmography, and pulse wave velocity and reflection. Methods A total of 30 subjects between 40 and 80 years of age with PAD who are limited by IC will undergo exercise training 3 days per week for 12 weeks (ie, 36 sessions). They will be randomized to either the EX+BR or EX+PL group where participants will consume a beverage high in inorganic nitrate (4.2 mmol) or a low-nitrate placebo, respectively, 3 hours prior to each training session. Results Data collection from this study has been completed and is in the process of analysis and write-up. While the study is too underpowered—EX+BR, n=11; EX+PL, n=13—to determine between-group differences in the primary outcomes of COT, PWT, and 6MW, preliminary observations are promising with Cohen d effect sizes of medium to large. Conclusions Exercise training is currently the most effective therapy to increase functional capacity in PAD+IC. If the addition of inorganic nitrate to an exercise regimen elicits greater benefits, it may redefine the current standard of care for PAD+IC. Trial Registration ClinicalTrials.gov NCT01684930; https://clinicaltrials.gov/ct2/show/NCT01684930 (Archived by WebCite at http://www.webcitation.org/6raXFyEcP) PMID:28974486

Experimental Validation of Plastic Mandible Models Produced by a "Low-Cost" 3-Dimensional Fused Deposition Modeling Printer.

PubMed

Maschio, Federico; Pandya, Mirali; Olszewski, Raphael

2016-03-22

The objective of this study was to investigate the accuracy of 3-dimensional (3D) plastic (ABS) models generated using a low-cost 3D fused deposition modelling printer. Two human dry mandibles were scanned with a cone beam computed tomography (CBCT) Accuitomo device. Preprocessing consisted of 3D reconstruction with Maxilim software and STL file repair with Netfabb software. Then, the data were used to print 2 plastic replicas with a low-cost 3D fused deposition modeling printer (Up plus 2®). Two independent observers performed the identification of 26 anatomic landmarks on the 4 mandibles (2 dry and 2 replicas) with a 3D measuring arm. Each observer repeated the identifications 20 times. The comparison between the dry and plastic mandibles was based on 13 distances: 8 distances less than 12 mm and 5 distances greater than 12 mm. The mean absolute difference (MAD) was 0.37 mm, and the mean dimensional error (MDE) was 3.76%. The MDE decreased to 0.93% for distances greater than 12 mm. Plastic models generated using the low-cost 3D printer UPplus2® provide dimensional accuracies comparable to other well-established rapid prototyping technologies. Validated low-cost 3D printers could represent a step toward the better accessibility of rapid prototyping technologies in the medical field.

Experimental Validation of Plastic Mandible Models Produced by a “Low-Cost” 3-Dimensional Fused Deposition Modeling Printer

PubMed Central

Maschio, Federico; Pandya, Mirali; Olszewski, Raphael

2016-01-01

Background The objective of this study was to investigate the accuracy of 3-dimensional (3D) plastic (ABS) models generated using a low-cost 3D fused deposition modelling printer. Material/Methods Two human dry mandibles were scanned with a cone beam computed tomography (CBCT) Accuitomo device. Preprocessing consisted of 3D reconstruction with Maxilim software and STL file repair with Netfabb software. Then, the data were used to print 2 plastic replicas with a low-cost 3D fused deposition modeling printer (Up plus 2®). Two independent observers performed the identification of 26 anatomic landmarks on the 4 mandibles (2 dry and 2 replicas) with a 3D measuring arm. Each observer repeated the identifications 20 times. The comparison between the dry and plastic mandibles was based on 13 distances: 8 distances less than 12 mm and 5 distances greater than 12 mm. Results The mean absolute difference (MAD) was 0.37 mm, and the mean dimensional error (MDE) was 3.76%. The MDE decreased to 0.93% for distances greater than 12 mm. Conclusions Plastic models generated using the low-cost 3D printer UPplus2® provide dimensional accuracies comparable to other well-established rapid prototyping technologies. Validated low-cost 3D printers could represent a step toward the better accessibility of rapid prototyping technologies in the medical field. PMID:27003456

Risk factors for early failure after peripheral endovascular intervention: application of a reliability engineering approach.

PubMed

Meltzer, Andrew J; Graham, Ashley; Connolly, Peter H; Karwowski, John K; Bush, Harry L; Frazier, Peter I; Schneider, Darren B

2013-01-01

We apply an innovative and novel analytic approach, based on reliability engineering (RE) principles frequently used to characterize the behavior of manufactured products, to examine outcomes after peripheral endovascular intervention. We hypothesized that this would allow for improved prediction of outcome after peripheral endovascular intervention, specifically with regard to identification of risk factors for early failure. Patients undergoing infrainguinal endovascular intervention for chronic lower-extremity ischemia from 2005 to 2010 were identified in a prospectively maintained database. The primary outcome of failure was defined as patency loss detected by duplex ultrasonography, with or without clinical failure. Analysis included univariate and multivariate Cox regression models, as well as RE-based analysis including product life-cycle models and Weibull failure plots. Early failures were distinguished using the RE principle of "basic rating life," and multivariate models identified independent risk factors for early failure. From 2005 to 2010, 434 primary endovascular peripheral interventions were performed for claudication (51.8%), rest pain (16.8%), or tissue loss (31.3%). Fifty-five percent of patients were aged ≥75 years; 57% were men. Failure was noted after 159 (36.6%) interventions during a mean follow-up of 18 months (range, 0-71 months). Using multivariate (Cox) regression analysis, rest pain and tissue loss were independent predictors of patency loss, with hazard ratios of 2.5 (95% confidence interval, 1.6-4.1; P < 0.001) and 3.2 (95% confidence interval, 2.0-5.2, P < 0.001), respectively. The distribution of failure times for both claudication and critical limb ischemia fit distinct Weibull plots, with different characteristics: interventions for claudication demonstrated an increasing failure rate (β = 1.22, θ = 13.46, mean time to failure = 12.603 months, index of fit = 0.99037, R(2) = 0.98084), whereas interventions for critical limb ischemia demonstrated a decreasing failure rate, suggesting the predominance of early failures (β = 0.7395, θ = 6.8, mean time to failure = 8.2, index of fit = 0.99391, R(2) = 0.98786). By 3.1 months, 10% of interventions failed. This point (90% reliability) was identified as the basic rating life. Using multivariate analysis of failure data, independent predictors of early failure (before 3.1 months) included tissue loss, long lesion length, chronic total occlusions, heart failure, and end-stage renal disease. Application of a RE framework to the assessment of clinical outcomes after peripheral interventions is feasible, and potentially more informative than traditional techniques. Conceptualization of interventions as "products" permits application of product life-cycle models that allow for empiric definition of "early failure" may facilitate comparative effectiveness analysis and enable the development of individualized surveillance programs after endovascular interventions. Copyright © 2013 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

A new management for limb graft occlusion after endovascular aneurysm repair adding a vollmar ring stripper: the unclogging technique.

PubMed

Ronsivalle, Salvatore; Faresin, Francesca; Franz, Francesca; Pedon, Luigi; Rettore, Carlo; Zonta, Loretta; Olivieri, Armando

2013-11-01

Lower extremity ischemia for limb thrombosis is a well-known adverse event after endovascular abdominal aortic aneurysm repair (EVAR), ranging from 2.6-7.4%. We report our experience in the management of graft limb occlusion that occurred in patients who underwent EVAR in our institution. In cases in which balloon catheter thrombectomy is not useful or is risky, it is important to take into consideration the use of a Vollmar ring stripper (Aesculap, San Jose, CA) to avoid dislodging or disrupting the sealing zones. This technique has taken from thromboendarterectomy the principle of detaching plaque from adventitia and transformed it in a less traumatic way for dissecting thromboses from endografts. Between September 1999 and December 2011, 608 patients underwent EVAR in our institution. In cases of severe claudication or critical ischemia, we tried to remove the thrombus using mild Fogarty balloon traction; in cases of progressive and old stratification, we added the Vollmar ring stripper. After recanalization, if there was a stenosis, an angioplasty was performed and in most patients an adequately size Cheatham platinum stent was positioned. If the endovascular approach failed, bypass procedures were considered. In 608 patients over a mean follow-up time of 72 months, there were 23 cases of limb thrombosis. Fifteen of the 23 limb occlusions were identified within 6 months after aneurysm repair. The mean time to occlusion was 8.2 ± 4.3 months (range: 20 days-25 months). Presenting symptoms were mild to moderate claudication (Rutherford classification I) in 3 patients (13%), medium severe claudication (Rutherford classification IIA) in 18 patients (78.3%), and paresthesia and rest pain (Rutherford classification IIB) in 2 patients (8.7%; 1 of those patients had a loss of motor function). Four (17.4%) were stable during follow-up, and in 1 of these cases we tried thrombolysis without thrombosis resolution. In 13 (56.5%) cases, we performed balloon catheter thrombectomy with a LeMaitre over the wire embolectomy catheter (LeMaitre Vascular, Burlington, MA). In 8 of 13 (61.5%) patients with certain thrombosis characteristics, we decided to add to the balloon catheter a Vollmar ring stripper for mechanical catheter thrombectomy. In all 13 thrombectomy cases, blood flow was restored through the limb with the endograft itself. There were no episodes of graft dislocation, disruption of the sealing zones, or recurrences. In 5 (21.7%) cases, a femorofemoral crossover was performed, and in 1 (4.3%) case, an axillofemoral bypass was performed. During the follow-up period, 2 of the 5 femorofemoral crossovers closed after 6 and 8 months, respectively. This unclogging technique, alone or associated with Vollmar ring stripper, proves to be simple, safe, and effective in the treatment of graft limb occlusion. Additional research will help confirm the role of Vollmar ring stripper. Copyright © 2013 Elsevier Inc. All rights reserved.