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Sample records for randomized multicentre phase

  1. Tretinoin Nanogel 0.025% Versus Conventional Gel 0.025% in Patients with Acne Vulgaris: A Randomized, Active Controlled, Multicentre, Parallel Group, Phase IV Clinical Trial

    PubMed Central

    Chandrashekhar, B S; Anitha, M.; Ruparelia, Mukesh; Vaidya, Pradyumna; Aamir, Riyaz; Shah, Sunil; Thilak, S; Aurangabadkar, Sanjeev; Pal, Sandeep; Saraswat, Abir

    2015-01-01

    Background: Conventional topical tretinoin formulation is often associated with local adverse events. Nanogel formulation of tretinoin has good physical stability and enables good penetration of tretinoin into the pilo-sebaceous glands. Aim: The present study was conducted to assess the efficacy and safety of a nanogel formulation of tretinoin as compared to its conventional gel formulation in the treatment of acne vulgaris of the face. Materials and Methods: This randomized, active controlled, multicentric, phase IV clinical trial evaluated the treatment of patients with acne vulgaris of the face by the two gel formulations locally applied once daily at night for 12 wk. Acne lesion counts (inflammatory, non-inflammatory & total) and severity grading were carried out on the monthly scheduled visits along with the tolerability assessments. Results: A total of 207 patients were randomized in the study. Reductions in the total (72.9% vs. 65.0%; p = 0.03) and inflammatory (78.1% vs. 66.9%; p = 0.02) acne lesions were reported to be significantly greater with the nanogel formulation as compared to the conventional gel formulation. Local adverse events were significantly less (p = 0.04) in the nanogel group (13.3%) as compared to the conventional gel group (24.7%). Dryness was the most common adverse event reported in both the treatment groups while peeling of skin, burning sensation and photosensitivity were reported in patients using the conventional gel only. Conclusion: In the treatment of acne vulgaris of the face, tretinoin nanogel formulation appears to be more effective and better tolerated than the conventional gel formulation. PMID:25738069

  2. Pre-operative chemotherapy in early stage resectable non-small-cell lung cancer: a randomized feasibility study justifying a multicentre phase III trial

    PubMed Central

    Boer, R H de; Smith, I E; Pastorino, U; O'Brien, M E R; Ramage, F; Ashley, S; Goldstraw, P

    1999-01-01

    Surgical resection offers the best chance for cure for early stage non-small-cell lung cancer (NSCLC, stage I, II, IIIA), but the 5-year survival rates are only moderate, with systemic relapse being the major cause of death. Pre-operative (neo-adjuvant) chemotherapy has shown promise in small trials restricted to stage IIIA patients. We believe similar trials are now appropriate in all stages of operable lung cancer. A feasibility study was performed in 22 patients with early stage (IB, II, IIIA) resectable NSCLC; randomized to either three cycles of chemotherapy [mitomycin-C 8 mg m−2, vinblastine 6 mg m−2 and cisplatin 50 mg m−2 (MVP)] followed by surgery (n = 11), or to surgery alone. Of 40 eligible patients, 22 agreed to participate (feasibility 55%) and all complied with the full treatment schedule. All symptomatic patients achieved either complete (50%) or partial (50%) relief of tumour-related symptoms with pre-operative chemotherapy. Fifty-five per cent achieved objective tumour response, and a further 27% minor tumour shrinkage; none had progressive disease. Partial pathological response was seen in 50%. No severe (WHO grade III–IV) toxicities occurred. No significant deterioration in quality of life was detected during chemotherapy. Pre-operative MVP chemotherapy is feasible in early stage NSCLC, and this study has now been initiated as a UK-wide Medical Research Council phase III trial. © 1999 Cancer Research Campaign PMID:10188899

  3. Chemotherapy with or without low-dose interleukin-2 in advanced non-small cell lung cancer: results from a phase III randomized multicentric trial.

    PubMed

    Ridolfi, Laura; Bertetto, Oscar; Santo, Antonio; Naglieri, Emanuele; Lopez, Massimo; Recchia, Francesco; Lissoni, Paolo; Galliano, Marco; Testore, Franco; Porta, Camillo; Maglie, Monica; Dall'agata, Monia; Fumagalli, Luca; Ridolfi, Ruggero

    2011-10-01

    Non-small cell lung cancer (NSCLC) is associated with IL-2-dependent cell-mediated immunodeficiency. As IL-2 is the main lymphocyte growth factor, a phase III randomized multicenter trial was conducted to evaluate the impact of subcutaneous low-dose IL-2 added to standard chemotherapy (CT) on overall survival (OS) in advanced NSCLC patients. Patients (n=241) with histologically confirmed stage IIIb or IV non-operable NSCLC underwent stratified randomization on the basis of center, ECOG PS, stage of disease and percentage of weight loss. Patients received gemcitabine (1000 mg/m2) on days 1 and 8 + cisplatin (100 mg/m2) on day 2 every 21 days for a maximum of 6 cycles [chemotherapy (CT) arm]. In the CT+IL-2 arm, patients also received low-dose subcutaneous IL-2 3,000,000 IU/die on days 3-5, 9-11, 15-17. The study had 90% power to detect a 20% absolute increase in 1-year OS with 118 patients/arm. An overall response (OR) rate of 12.8% (14% in the CT+IL-2 arm and 11.4% in CT arm) was observed. Stable disease was 70 and 66.7%, and progressive disease 16 and 21.8% in the CT+IL-2 and CT arms, respectively. No differences in response were found in any subgroup analysis. At a median follow-up of 32 months, 1-year OS was 45% for the CT+IL-2 arm vs. 51% for the CT arm (p=0.456 log-rank). Median progression-free survival was 6.6 months in the CT+IL-2 arm vs. 6.9 months in the CT arm (p=0.573, log-rank). A higher number of grade 4 toxicities were reported with CT+IL-2. The most common grade ≥3 adverse events were gastrointestinal toxicity (mainly nausea and diarrhea) and myelosuppression. No relevant differences in clinical outcome were observed from the addition of IL-2 to CT. Future studies investigating the role of T-regulators in chemoimmunotherapeutic regimens could be performed. PMID:21720704

  4. Ketoprofen versus paracetamol (acetaminophen) or ibuprofen in the management of fever: results of two randomized, double-blind, double-dummy, parallel-group, repeated-dose, multicentre, phase III studies in children.

    PubMed

    Kokki, Hannu; Kokki, Merja

    2010-01-01

    Fever is a common symptom in children and one of the major concerns of parents of younger and preschool-age children. To compare the efficacy and safety of ketoprofen with that of paracetamol (acetaminophen) and ibuprofen in the treatment of febrile conditions in children. Two prospective, randomized, double-blind, double-dummy, repeated-dose, multicentre, phase III studies with two parallel groups in each study were conducted in primary-care outpatient clinics. Children aged 6 months to 6 years presenting with a febrile condition and an oral body temperature of > or =38.8 degrees C or rectal temperature of > or =39 degrees C were eligible for inclusion. Patients were randomized to receive either ketoprofen syrup 0.5 mg/kg, ibuprofen suspension 5 mg/kg or paracetamol suspension 15 mg/kg every 6 hours by the oral route. The primary outcome measure was the change in temperature at 3 hours (H3), compared with baseline (H0). All three treatments provided similar mean maximum decreases of 1.4-1.5 degrees C in body temperature at H3 compared with H0. Use of ketoprofen was not associated with any increased risk of adverse events compared with the two reference compounds. Ketoprofen 0.5 mg/kg appeared to be equivalent to the standard antipyretic doses of the reference products ibuprofen 5 mg/kg and paracetamol 15 mg/kg. Ketoprofen at the 0.5 mg/kg dose should be an effective and safe option for symptomatic management of fever in children. PMID:20380479

  5. Gemcitabine, oxaliplatin, levofolinate, 5-fluorouracil, granulocyte-macrophage colony-stimulating factor, and interleukin-2 (GOLFIG) versus FOLFOX chemotherapy in metastatic colorectal cancer patients: the GOLFIG-2 multicentric open-label randomized phase III trial.

    PubMed

    Correale, Pierpaolo; Botta, Cirino; Rotundo, Maria S; Guglielmo, Annamaria; Conca, Raffaele; Licchetta, Antonella; Pastina, Pierpaolo; Bestoso, Elena; Ciliberto, Domenico; Cusi, Maria G; Fioravanti, Antonella; Guidelli, Giacomo M; Bianco, Maria T; Misso, Gabriella; Martino, Elodia; Caraglia, Michele; Tassone, Pierfrancesco; Mini, Enrico; Mantovani, Giovanni; Ridolfi, Ruggero; Pirtoli, Luigi; Tagliaferri, Pierosandro

    2014-01-01

    The GOLFIG-2 phase III trial was designed to compare the immunobiological activity and antitumor efficacy of GOLFIG chemoimmunotherapy regimen with standard FOLFOX-4 chemotherapy in frontline treatment of metastatic colorectal cancer (mCRC) patients. This trial was conceived on the basis of previous evidence of antitumor and immunomodulating activity of the GOLFIG regimen in mCRC. GOLFIG-2 is a multicentric open/label phase III trial (EUDRACT: 2005-003458-81). Chemo-naive mCRC patients were randomized in a 1:1 ratio to receive biweekly standard FOLFOX-4 or GOLFIG [gemcitabine (1000 mg/m(2), day 1); oxaliplatin (85 mg/m(2), day 2); levofolinate (100 mg/m(2), days 1-2), 5-fluorouracil (5-FU) (400 mg/m(2) in bolus followed by 24 h infusion at 800 mg/m(2),days 1-2), sc. GM-CSF (100 μg, days 3-7); sc. aldesleukin (0·5 MIU bi-daily, days 8-14 and 17-30)] treatments. The study underwent early termination because of poor recruitment in the control arm. After a median follow-up of 43.83 months, GOLFIG regimen showed superiority over FOLFOX in terms of progression-free survival [median 9·23 (95% confidence interval (CI), 6·9-11.5) vs. median 5.70 (95% CI, 3.38-8.02) months; hazard ratio (HR): 0.52 (95% CI, 0.35-0.77), P=0·002] and response rate [66.1% (95% CI, 0.41-0.73) vs. 37·0% (95% CI, 0.28-0.59), P=0.002], with a trend to longer survival [median 21.63 (95% CI, 18.09-25.18) vs. 14.57 mo (95% CI, 9.07-20.07); HR: 0·79 (95% CI, 0.52-1.21); P=0.28]. Patients in the experimental arm showed higher incidence of non-neutropenic fever (18.5%), autoimmunity signs (18.5%), an increase in the number of monocytes, eosinophils, CD4(+) T lymphocytes, natural killer cells, and a decrease in immunoregulatory (CD3(+)CD4(+)CD25(+)FoxP3(+)) T cells. Taken together, these findings provide proof-of-principle that GOLFIG chemoimmunotherapy may represent a novel reliable option for first-line treatment of mCRC. PMID:24316553

  6. Treatment of chronic idiopathic urticaria with levamisole: a multicentre, randomized, double-blind, controlled trial.

    PubMed

    Zhang, H; Shan, C; Hua, Z; Zhao, P; Zhang, H

    2009-01-01

    The objective of this study was to evaluate the efficacy of treating chronic idiopathic urticaria (CIU) with levamisole in combination with levocetirizine. This was a multicentre, randomized, double-blind, controlled trial that included 132 patients with active CIU who were treated for 6 weeks with either levocetirizine alone (control group; n = 65) or levamisole plus levocetirizine (treatment group; n = 67). Response to therapy was evaluated by measuring the efficacy rate. After 2 weeks of treatment, there was no significant difference in the efficacy rate between the treatment and control groups (54.84% and 42.37%, respectively). After 6 weeks of treatment, a statistically significant difference in the efficacy rate was observed between the groups (76.27% and 54.39% for the treatment and control groups, respectively). This study demonstrated that a combination of levamisole plus levocetirizine is more effective than levocetirizine alone and potentially provides a new, promising approach to the treatment of CIU. PMID:19761700

  7. Efficacy and Safety of FospropofolFD Compared to Propofol When Given During the Induction of General Anaesthesia: A Phase II, Multi-centre, Randomized, Parallel-Group, Active-Controlled, Double-Blind, Double-Dummy Study.

    PubMed

    Liu, Rong; Luo, Chaozhi; Liu, Jin; Zhang, Wensheng; Li, Yan; Xu, Jing

    2016-07-01

    The present phase II study aimed to compare the efficacy and safety of fospropofol disodium for injection (FospropofolFD ) and propofol when given during the induction of general anaesthesia in patients scheduled for elective surgery. FospropofolFD is a water-soluble prodrug of propofol. Approved by the Ethical Committee, 240 participants aged 18-65 years were equally randomly allocated to receive an intravenous bolus of FospropofolFD 20 mg/kg or propofol 2 mg/kg without any anaesthetic pre-treatment. The primary efficacy end-point was the sedation success rate within 5 min. after administering investigational drugs (the sedation success is defined as obtaining Modified Observer's Assessment of Alertness/Sedation scale score of 1). All the participants completed the induction and intubation within 25 min. after administration. The sedation success rates within 5 min. after administration of FospropofolFD 20 mg/kg and propofol 2 mg/kg were 94.50% versus 100% in the intention-to-treat population and 95.10% versus 100% in the per-protocol population, respectively. The non-inferiority test obtained a p-value less than 0.025, and the lower limits of the one-sided 97.5% confidence interval were more than -0.09. This meant that FospropofolFD 20 mg/kg was considered non-inferior to propofol 2 mg/kg for the primary efficacy end-point. Compared with propofol 2 mg/kg, FospropofolFD 20 mg/kg had a slower sedation efficacy. No serious adverse events were observed in the two groups. The sedation success rate within 5 min. after administration of FospropofolFD 20 mg/kg was non-inferior to propofol 2 mg/kg, and FospropofolFD 20 mg/kg can be used for the induction of general anaesthesia safely. PMID:26781338

  8. Adjuvant low-dose interleukin-2 (IL-2) plus interferon-α (IFN-α) in operable renal cell carcinoma (RCC): a phase III, randomized, multicentre trial of the Italian Oncology Group for Clinical Research (GOIRC).

    PubMed

    Passalacqua, Rodolfo; Caminiti, Caterina; Buti, Sebastiano; Porta, Camillo; Camisa, Roberta; Braglia, Luca; Tomasello, Gianluca; Vaglio, Augusto; Labianca, Roberto; Rondini, Ermanno; Sabbatini, Roberto; Nastasi, Giuseppe; Artioli, Fabrizio; Prati, Andrea; Potenzoni, Michele; Pezzuolo, Debora; Oliva, Elena; Alberici, Federico; Buzio, Carlo

    2014-01-01

    There is currently no standard therapy to reduce the recurrence rate after surgery for renal cell carcinoma (RCC). The aim of this study was to assess efficacy and safety of adjuvant treatment with low doses of interleukin-2 (IL-2)+interferon-α (IFN-α) in operable RCC. The patients were randomized 1:1 to receive a 4-week cycle of low-dose IL-2+IFN-α or observation after primary surgery for RCC. Treatment cycles were repeated every 4 months for the first 2 years and every 6 months for the subsequent 3 years. The primary endpoint was recurrence-free survival (RFS); safety; and overall survival (OS) were secondary endpoints. ClinicalTrials.gov registration number was NCT00502034. 303/310 randomized patients (156 in the immunotherapy arm and 154 in the observation group) were evaluable at the intention-to-treat analyses. The 2 arms were well balanced. At a median follow-up of 52 months (range, 12-151 mo), RFS, and OS were similar, with an estimated hazard ratio (HR) of 0.84 [95% confidence interval (CI), 0.54-1.31; P=0.44] and of 1.07 (95% CI, 0.64-1.79; P=0.79), respectively in the 2 groups. Unplanned, subgroup analysis showed a positive effect of the treatment for patients with age 60 years and younger, pN0, tumor grades 1-2, and pT3a stage. Among patients with the combined presence of ≥ 2 of these factors, immunotherapy had a positive effect on RFS (HR=0.44; 95% CI, 0.24-0.82; P ≤ 0.01), whereas patients with <2 factors in the treatment arm exhibited a significant poorer OS (HR=2.27; 95% CI, 1.03-5.03 P=0.037). Toxicity of immunotherapy was mild and limited to World Health Organization grade 1-2 in most cases. Adjuvant immunotherapy with IL-2+IFN-α showed no RFS or OS improvement in RCC patients who underwent radical surgery. The results of subset analysis here presented are only hypothesis generating. PMID:25304727

  9. L-Carnitine-supplementation in advanced pancreatic cancer (CARPAN) - a randomized multicentre trial

    PubMed Central

    2012-01-01

    Background Cachexia, a >10% loss of body-weight, is one factor determining the poor prognosis of pancreatic cancer. Deficiency of L-Carnitine has been proposed to cause cancer cachexia. Findings We screened 152 and enrolled 72 patients suffering from advanced pancreatic cancer in a prospective, multi-centre, placebo-controlled, randomized and double-blinded trial to receive oral L-Carnitine (4 g) or placebo for 12 weeks. At entry patients reported a mean weight loss of 12 ± 2,5 (SEM) kg. During treatment body-mass-index increased by 3,4 ± 1,4% under L-Carnitine and decreased (−1,5 ± 1,4%) in controls (p < 0,05). Moreover, nutritional status (body cell mass, body fat) and quality-of-life parameters improved under L-Carnitine. There was a trend towards an increased overall survival in the L-Carnitine group (median 519 ± 50 d versus 399 ± 43 d, not significant) and towards a reduced hospital-stay (36 ± 4d versus 41 ± 9d,n.s.). Conclusion While these data are preliminary and need confirmation they indicate that patients with pancreatic cancer may have a clinically relevant benefit from the inexpensive and well tolerated oral supplementation of L-Carnitine. PMID:22824168

  10. Treatment Extension of Pegylated Interferon Alpha and Ribavirin Does Not Improve SVR in Patients with Genotypes 2/3 without Rapid Virological Response (OPTEX Trial): A Prospective, Randomized, Two-Arm, Multicentre Phase IV Clinical Trial

    PubMed Central

    Heidrich, Benjamin; Cordes, Hans-Jörg; Klinker, Hartwig; Möller, Bernd; Naumann, Uwe; Rössle, Martin; Kraus, Michael R.; Böker, Klaus H.; Roggel, Christoph; Schuchmann, Marcus; Stoehr, Albrecht; Trein, Andreas; Hardtke, Svenja; Gonnermann, Andrea; Koch, Armin; Wedemeyer, Heiner; Manns, Michael P.; Cornberg, Markus

    2015-01-01

    Although sofosbuvir has been approved for patients with genotypes 2/3 (G2/3), many parts of the world still consider pegylated Interferon alpha (P) and ribavirin (R) as standard of care for G2/3. Patients with rapid virological response (RVR) show response rates >80%. However, SVR (sustained virological response) in non-RVR patients is not satisfactory. Longer treatment duration may be required but evidence from prospective trials are lacking. A total of 1006 chronic HCV genotype 2/3 patients treated with P/R were recruited into a German HepNet multicenter screening registry. Of those, only 226 patients were still HCV RNA positive at week 4 (non-RVR). Non-RVR patients with ongoing response after 24 weeks P-2b/R qualified for OPTEX, a randomized trial investigating treatment extension of additional 24 weeks (total 48 weeks, Group A) or additional 12 weeks (total 36 weeks, group B) of 1.5 μg/kg P-2b and 800-1400 mg R. Due to the low number of patients without RVR, the number of 150 anticipated study patients was not met and only 99 non-RVR patients (n=50 Group A, n=49 Group B) could be enrolled into the OPTEX trial. Baseline factors did not differ between groups. Sixteen patients had G2 and 83 patients G3. Based on the ITT (intention-to-treat) analysis, 68% [55%; 81%] in Group A and 57% [43%; 71%] in Group B achieved SVR (p= 0.31). The primary endpoint of better SVR rates in Group A compared to a historical control group (SVR 70%) was not met. In conclusion, approximately 23% of G2/3 patients did not achieve RVR in a real world setting. However, subsequent recruitment in a treatment-extension study was difficult. Prolonged therapy beyond 24 weeks did not result in higher SVR compared to a historical control group. Trial Registration ClinicalTrials.gov NCT00803309 PMID:26057627

  11. Spinal cord stimulation in patients with painful diabetic neuropathy: a multicentre randomized clinical trial.

    PubMed

    de Vos, Cecile C; Meier, Kaare; Zaalberg, Paul Brocades; Nijhuis, Harold J A; Duyvendak, Wim; Vesper, Jan; Enggaard, Thomas P; Lenders, Mathieu W P M

    2014-11-01

    Painful diabetic neuropathy (PDN) is a peripheral neuropathic pain condition that is often difficult to relieve. Spinal cord stimulation (SCS) is a proven effective therapy for various types of mixed neuropathic conditions, yet effectiveness of SCS treatment for PDN is not well established. To our knowledge, ours is the first multicentre randomized controlled trial investigating the effectiveness of SCS in patients with PDN. Sixty patients with PDN in the lower extremities refractory to conventional medical therapy were enrolled and followed for 6 months. They were randomized 2:1 to best conventional medical practice with (SCS group) or without (control group) additional SCS therapy, and both groups were assessed at regular intervals. At each follow-up visit, the EuroQoL 5D, the short form McGill Pain Questionnaire (SF-MPQ) and a visual analogue scale (VAS, ranging 0-100) to measure pain intensity were recorded. The average VAS score for pain intensity was 73 in the SCS group and 67 in the control group at baseline. After 6 months of treatment, the average VAS score was significantly reduced to 31 in the SCS group (P<.001) and remained 67 (P=.97) in the control group. The SF-MPQ and EuroQoL 5D questionnaires also showed that patients in the SCS group, unlike those in the control group, experienced reduced pain and improved health and quality of life after 6 months of treatment. In patients with refractory painful diabetic neuropathy, spinal cord stimulation therapy significantly reduced pain and improved quality of life. PMID:25180016

  12. Prevention of sternal wound complications after sternotomy: results of a large prospective randomized multicentre trial†

    PubMed Central

    Gorlitzer, Michael; Wagner, Florian; Pfeiffer, Steffen; Folkmann, Sandra; Meinhart, Johann; Fischlein, Theodor; Reichenspurner, Hermann; Grabenwoeger, Martin

    2013-01-01

    OBJECTIVES A prospective randomized multicentre trial was performed to analyse the efficacy of a vest (Posthorax support vest®) to prevent sternal wound infection after cardiac surgery, and to identify risk factors. METHODS From September 2007 to March 2010, 2539 patients undergoing cardiac surgery via median sternotomy were prospectively randomized into those who received a Posthorax® vest and those who did not. Patients were instructed to wear the vest postoperatively for 24 h a day for at least 6 weeks; the duration of follow-up was 90 days. Patients who did not use the vest within a period of 72 h postoperatively were regarded as study dropouts. Statistical calculations were based on an intention-to-treat (ITT) analysis. Further evaluations comprised all subgroups of patients. RESULTS Complete data were available for 2539 patients (age 67 ± 11years, 45% female). Of these, 1351 were randomized to receive a vest, while 1188 received no vest. No significant differences were observed between groups regarding age, gender, diabetes, body mass index, chronic obstructive pulmonary disease (COPD), renal failure, the logistic EuroSCORE and the indication for surgery. The frequency of deep wound complications (dWC: mediastinitis and sternal dehiscence) was significantly lower in vest (n = 14; 1.04%) vs non-vest (n = 27; 2.27%) patients (ITT, P < 0.01), but superficial complications did not differ between groups. Subanalysis of vest patients revealed that only 933 (Group A) wore the vest according to the protocol, while 202 (Group BR) refused to wear the vest (non-compliance) and 216 (Group BN) did not use the vest for other reasons. All dWC occurred in Groups BR (n = 7) and BN (n = 7), although these groups had the same preoperative risk profile as Group A. Postoperatively, Group BN had a prolonged intubation time, a longer stay in the intensive care unit, greater use of intra-aortic balloon pump, higher frequency of COPD and a larger percentage of patients who

  13. A multicentre phase II study of cisplatin and gemcitabine for malignant mesothelioma

    PubMed Central

    Nowak, A K; Byrne, M J; Williamson, R; Ryan, G; Segal, A; Fielding, D; Mitchell, P; Musk, A W; Robinson, B W S

    2002-01-01

    Our previous phase II study of cisplatin and gemcitabine in malignant mesothelioma showed a 47.6% (95% CI 26.2–69.0%) response rate with symptom improvement in responding patients. Here we confirm these findings in a multicentre setting, and assess the effect of this treatment on quality of life and pulmonary function. Fifty-three patients with pleural malignant mesothelioma received cisplatin 100 mg m−2 i.v. day 1 and gemcitabine 1000 mg m−2 i.v. days 1, 8, and 15 of a 28 day cycle for a maximum of six cycles. Quality of life and pulmonary function were assessed at each cycle. The best response achieved in 52 assessable patients was: partial response, 17 (33%, 95% CI 20–46%); stable disease, 31 (60%); and progressive disease, four (8%). The median time to disease progression was 6.4 months, median survival from start of treatment 11.2 months, and median survival from diagnosis 17.3 months. Vital capacity and global quality of life remained stable in all patients and improved significantly in responding patients. Major toxicities were haematological, limiting the mean relative dose intensity of gemcitabine to 75%. This schedule of cisplatin and gemcitabine is active in malignant mesothelioma in a multicentre setting. Investigation of alternative scheduling is needed to decrease haematological toxicity and increase the relative dose intensity of gemcitabine whilst maintaining response rate and quality of life. British Journal of Cancer (2002) 87, 491–496. doi:10.1038/sj.bjc.6600505 www.bjcancer.com © 2002 Cancer Research UK PMID:12189542

  14. The optimized acupuncture treatment for neck pain caused by cervical spondylosis: a study protocol of a multicentre randomized controlled trial

    PubMed Central

    2012-01-01

    Background Neck pain is one of the chief symptoms of cervical spondylosis (CS). Acupuncture is a well-accepted and widely used complementary therapy for the management of neck pain caused by CS. In this paper, we present a randomized controlled trial protocol evaluating the use of acupuncture for CS neck pain, comparing the effects of the optimized acupuncture therapy in real practice compared with sham and shallow acupuncture. Methods/Design This trial uses a multicentre, parallel-group, randomized, sham acupuncture and shallow acupuncture, controlled single-blind design. Nine hospitals are involved as trial centres. 945 patients who meet inclusion criteria are randomly assigned to receive optimized acupuncture therapy, sham acupuncture or shallow acupuncture by a computerized central randomization system. The interventions past for 4 weeks with eight to ten treatments in total. The group allocations and interventions are concealed to patients and statisticians. The Northwick Park Neck Pain Questionnaire (NPQ) is used as the primary outcome measure, and the McGill Pain Questionnaire (MPQ) and The Short Form (36) Health Survey (SF-36) are applied as secondary outcome measures. The evaluation is performed at baseline, at the end of the intervention, and at the end of the first month and the third month during follow-up. The statistical analyses will include baseline data comparison and repeated measures of analysis of variance (ANOVA) for primary and secondary outcomes of group and time differences. Adverse events (AEs) will be reported if they occur. Discussion This trial is a multicentre randomized control trial (RCT) on the efficacy of acupuncture for CS neck pain and has a large sample size and central randomization in China. It will strictly follow the CONSORT statement and STRICTA extension guideline to report high-quality study results. By setting the control groups as sham and shallow acupuncture, this study attempts to reveal the effects of real acupuncture

  15. Azithromycin for Indigenous children with bronchiectasis: study protocol for a multi-centre randomized controlled trial

    PubMed Central

    2012-01-01

    Background The prevalence of chronic suppurative lung disease (CSLD) and bronchiectasis unrelated to cystic fibrosis (CF) among Indigenous children in Australia, New Zealand and Alaska is very high. Antibiotics are a major component of treatment and are used both on a short or long-term basis. One aim of long-term or maintenance antibiotics is to reduce the frequency of acute pulmonary exacerbations and symptoms. However, there are few studies investigating the efficacy of long-term antibiotic use for CSLD and non-CF bronchiectasis among children. This study tests the hypothesis that azithromycin administered once a week as maintenance antibiotic treatment will reduce the rate of pulmonary exacerbations in Indigenous children with bronchiectasis. Methods/design We are conducting a multicentre, randomised, double-blind, placebo controlled clinical trial in Australia and New Zealand. Inclusion criteria are: Aboriginal, Torres Strait Islander, Maori or Pacific Island children aged 1 to 8 years, diagnosed with bronchiectasis (or probable bronchiectasis) with no underlying disease identified (such as CF or primary immunodeficiency), and having had at least one episode of pulmonary exacerbation in the last 12 months. After informed consent, children are randomised to receive either azithromycin (30 mg/kg once a week) or placebo (once a week) for 12–24 months from study entry. Primary outcomes are the rate of pulmonary exacerbations and time to pulmonary exacerbation determined by review of patient medical records. Secondary outcomes include length and severity of pulmonary exacerbation episodes, changes in growth, school loss, respiratory symptoms, forced expiratory volume in 1-second (FEV1; for children ≥6 years), and sputum characteristics. Safety endpoints include serious adverse events. Antibiotic resistance in respiratory bacterial pathogens colonising the nasopharynx is monitored. Data derived from medical records and clinical assessments every 3 to 4

  16. Randomized Grain Boundary Liquid Crystal Phase

    NASA Astrophysics Data System (ADS)

    Chen, D.; Wang, H.; Li, M.; Glaser, M.; Maclennan, J.; Clark, N.

    2012-02-01

    The formation of macroscopic, chiral domains, in the B4 and dark conglomerate phases, for example, is a feature of bent-core liquid crystals resulting from the interplay of chirality, molecular bend and molecular tilt. We report a new, chiral phase observed in a hockey stick-like liquid crystal molecule. This phase appears below a smectic A phase and cools to a crystal phase. TEM images of the free surface of the chiral phase show hundreds of randomly oriented smectic blocks several hundred nanometers in size, similar to those seen in the twist grain boundary (TGB) phase. However, in contrast to the TGB phase, these blocks are randomly oriented. The characteristic defects in this phase are revealed by freeze-fracture TEM images. We will show how these defects mediate the randomized orientation and discuss the intrinsic mechanism driving the formation of this phase. This work is supported by NSF MRSEC Grant DMR0820579 and NSF Grant DMR0606528.

  17. Effect of melatonin on incidence of delirium among patients with hip fracture: a multicentre, double-blind randomized controlled trial

    PubMed Central

    de Jonghe, Annemarieke; van Munster, Barbara C.; Goslings, J. Carel; Kloen, Peter; van Rees, Carolien; Wolvius, Reinder; van Velde, Romuald; Levi, Marcel; de Haan, Rob J.; de Rooij, Sophia E.

    2014-01-01

    Background: Disturbance of the sleep–wake cycle is a characteristic of delirium. In addition, changes in melatonin rhythm influence the circadian rhythm and are associated with delirium. We compared the effect of melatonin and placebo on the incidence and duration of delirium. Methods: We performed this multicentre, double-blind, randomized controlled trial between November 2008 and May 2012 in 1 academic and 2 nonacademic hospitals. Patients aged 65 years or older who were scheduled for acute hip surgery were eligible for inclusion. Patients received melatonin 3 mg or placebo in the evening for 5 consecutive days, starting within 24 hours after admission. The primary outcome was incidence of delirium within 8 days of admission. We also monitored the duration of delirium. Results: A total of 452 patients were randomly assigned to the 2 study groups. We subsequently excluded 74 patients for whom the primary end point could not be measured or who had delirium before the second day of the study. After these postrandomization exclusions, data for 378 patients were included in the main analysis. The overall mean age was 84 years, 238 (63.0%) of the patients lived at home before admission, and 210 (55.6%) had cognitive impairment. We observed no effect of melatonin on the incidence of delirium: 55/186 (29.6%) in the melatonin group v. 49/192 (25.5%) in the placebo group; difference 4.1 (95% confidence interval −0.05 to 13.1) percentage points. There were no between-group differences in mortality or in cognitive or functional outcomes at 3-month follow-up. Interpretation: In this older population with hip fracture, treatment with melatonin did not reduce the incidence of delirium. Trial registration: Netherlands Trial Registry, NTR1576: MAPLE (Melatonin Against PLacebo in Elderly patients) study; www.trialregister.nl/trialreg/admin/rctview.asp?TC=1576 PMID:25183726

  18. A comparison of topical application of penciclovir 1% cream with acyclovir 3% cream for treatment of genital herpes: a randomized, double-blind, multicentre trial.

    PubMed

    Chen, X S; Han, G Z; Guo, Z P; Lu, N Z; Chen, J; Wang, J B

    2000-09-01

    Genital herpes simplex virus (HSV) infection, a sexually transmitted disease (STD), is the commonest cause of ulcerative genital infections among the young and adult population. The significant association of genital ulceration and transmission of human immunodeficiency virus (HIV) has been shown in many studies. To explore the potential efficacy of topical treatment of genital herpes with penciclovir cream, a randomized, double-blind, multicentre, acyclovir-controlled Phase II clinical trial of penciclovir 1% cream 5 times daily up to 7 days for suppression of genital herpes was conducted in China. A total of 205 patients aged 20-59 years (mean age 36.0+/-8.8 years for acyclovir and 34.8+/-8.4 years for penciclovir) with a clinical diagnosis of genital herpes were randomly allocated to one of the 2 parallel treatment groups and used for analysis. Clinical assessment were made before treatment and followed up at every visit during the study. Our results show that there was an encouraging improvement simultaneously in the 2 groups although no significant differences in clinical efficacy with respect to clinical cure rate, and times to healing, resolution of all symptoms, absence of blisters, cessation of new blisters, crusting, and loss of crust between penciclovir and acyclovir groups in terms of primary, non-primary and total patients were found. However a significantly shorter time to crusting was found in primary penciclovir group when compared with primary acyclovir group. Adverse experience was generally infrequent and mild, and was comparable in the 2 treatment groups. Based on these preliminary clinical findings, further evaluation of penciclovir 3% cream for topical treatment of genital herpes is planned. PMID:10997497

  19. Phase transitions on random lattices: how random is topological disorder?

    PubMed

    Barghathi, Hatem; Vojta, Thomas

    2014-09-19

    We study the effects of topological (connectivity) disorder on phase transitions. We identify a broad class of random lattices whose disorder fluctuations decay much faster with increasing length scale than those of generic random systems, yielding a wandering exponent of ω=(d-1)/(2d) in d dimensions. The stability of clean critical points is thus governed by the criterion (d+1)ν>2 rather than the usual Harris criterion dν>2, making topological disorder less relevant than generic randomness. The Imry-Ma criterion is also modified, allowing first-order transitions to survive in all dimensions d>1. These results explain a host of puzzling violations of the original criteria for equilibrium and nonequilibrium phase transitions on random lattices. We discuss applications, and we illustrate our theory by computer simulations of random Voronoi and other lattices. PMID:25279615

  20. Video-based feedback of oral clinical presentations reduces the anxiety of ICU medical students: a multicentre, prospective, randomized study

    PubMed Central

    2014-01-01

    Background Oral presentations of clinical cases by medical students during medical rounds in hospital wards are a source of anxiety and little is known about how this anxiety can be alleviated. The objective of this study was to investigate whether video-based feedback of public oral presentations can reduce anxiety in 4th year medical students. Methods Multicentre randomized study conducted in six intensive care units (ICU) and emergency departments (ED) in France over a 9-month period in 2012. One hundred and forty two 4th year medical students were randomized to two groups: intervention and control. Students in the intervention group were recorded while making an oral presentation of a patient during morning ward rounds, followed by video-based feedback. Students in the control group conducted presented classical oral presentations without being filmed and with no formal feedback. Anxiety levels during a public oral presentation were assessed using the Spielberger State Anxiety Inventory (STAI-S). The primary outcome was the difference in STAI-S scores between groups at the beginning and at the end of a 3-month ICU or ED internship. Results Seventy four students were randomized to the ‘video-based feedback’ group and 68 were randomized to the control group. In both groups, STAI-S scores were significantly lower after 3 months of internship. However, the reduction in STAI-S scores was significantly greater in the “video-based feedback” group than in controls (-9.2 ± 9.3 vs. –4.6 ± 8.2, p = 0.024. Compared to the control group, significantly fewer students with high-level anxiety were observed in the “video-based feedback” group after 3 months of internship (68 vs. 28%, p <0.001). Conclusions Compared to “usual practice”, video-assisted oral feedback reduced anxiety and significantly decreased the proportion of students experiencing severe anxiety. PMID:24885005

  1. Short-course eflornithine in Gambian trypanosomiasis: a multicentre randomized controlled trial.

    PubMed Central

    Pépin, J.; Khonde, N.; Maiso, F.; Doua, F.; Jaffar, S.; Ngampo, S.; Mpia, B.; Mbulamberi, D.; Kuzoe, F.

    2000-01-01

    OBJECTIVE: A randomized controlled trial was conducted to determine whether 7 days of intravenous eflornithine (100 mg/kg every 6 h) was as effective as the standard 14-day regimen in the treatment of late-stage Trypanosoma brucei gambiense trypanosomiasis. METHODS: A total of 321 patients (274 new cases, 47 relapsing cases) were randomized at four participating centres in Congo, Côte d'Ivoire, the Democratic Republic of the Congo, and Uganda to one of these treatment regimens and followed up for 2 years. RESULTS: Six patients died during treatment, one of whom was on the 7-day regimen, whereas the other five had been on the 14-day regimen (P = 0.2). The response to eflornithine differed markedly between Uganda and other countries. Among new cases in Uganda, the 2-year probability of cure was 73% on the 14-day course compared with 62% on the 7-day regimen (hazard ratio (HR) for treatment failure, 7-day versus 14-day regimen: 1.45, 95% CI: 0.7, 3.1, P = 0.3). Among new cases in Côte d'Ivoire, Congo, and the Democratic Republic of the Congo combined, the 2-year probability of cure was 97% on the 14-day course compared with 86.5% on the 7-day regimen (HR for treatment failure, 7-day vs 14-day: 6.72, 95% confidence interval (CI): 1.5, 31.0, P = 0.003). Among relapsing cases in all four countries, the 2-year probability of cure was 94% with 7 days and 100% with 14 days of treatment. Factors associated with a higher risk of treatment failure were: a positive lymph node aspirate (HR 4.1; 95% CI: 1.8-9.4), a cerebrospinal fluid (CSF) white cell count > or = 100/mm3 (HR 3.5; 95% CI: 1.1-10.9), being treated in Uganda (HR 2.9; 95% CI: 1.4-5.9), and CSF trypanosomes (HR 1.9; 95% CI: 0.9-4.1). Being stuporous on admission was associated with a lower risk of treatment failure (HR 0.18; 95% CI: 0.02-1.4) as was increasing age (HR 0.977; 95% CI: 0.95-1.0, for each additional year of age). DISCUSSION: The 7-day course of eflornithine is an effective treatment of relapsing cases

  2. Pioglitazone in early Parkinson's disease: a phase 2, multicentre, double-blind, randomised trial

    PubMed Central

    2015-01-01

    Summary Background A systematic assessment of potential disease-modifying compounds for Parkinson's disease concluded that pioglitazone could hold promise for the treatment of patients with this disease. We assessed the effect of pioglitazone on the progression of Parkinson's disease in a multicentre, double-blind, placebo-controlled, futility clinical trial. Methods Participants with the diagnosis of early Parkinson's disease on a stable regimen of 1 mg/day rasagiline or 10 mg/day selegiline were randomly assigned (1:1:1) to 15 mg/day pioglitazone, 45 mg/day pioglitazone, or placebo. Investigators were masked to the treatment assignment. Only the statistical centre and the central pharmacy knew the treatment name associated with the randomisation number. The primary outcome was the change in the total Unified Parkinson's Disease Rating Scale (UPDRS) score between the baseline and 44 weeks, analysed by intention to treat. The primary null hypothesis for each dose group was that the mean change in UPDRS was 3 points less than the mean change in the placebo group. The alternative hypothesis (of futility) was that pioglitazone is not meaningfully different from placebo. We rejected the null if there was significant evidence of futility at the one-sided alpha level of 0.10. The study is registered at ClinicalTrials.gov, number NCT01280123. Findings 210 patients from 35 sites in the USA were enrolled between May 10, 2011, and July 31, 2013. The primary analysis included 72 patients in the 15 mg group, 67 in the 45 mg group, and 71 in the placebo group. The mean total UPDRS change at 44 weeks was 4.42 (95% CI 2.55–6.28) for 15 mg pioglitazone, 5.13 (95% CI 3.17–7.08) for 45 mg pioglitazone, and 6.25 (95% CI 4.35–8.15) for placebo (higher change scores are worse). The mean difference between the 15 mg and placebo groups was −1.83 (80% CI −3.56 to −0.10) and the null hypothesis could not be rejected (p=0.19). The mean difference between the 45 mg and placebo

  3. A multicentre, open-label, randomized comparative study of tigecycline versus ceftriaxone sodium plus metronidazole for the treatment of hospitalized subjects with complicated intra-abdominal infections.

    PubMed

    Towfigh, S; Pasternak, J; Poirier, A; Leister, H; Babinchak, T

    2010-08-01

    Tigecycline (TGC) has demonstrated clinical efficacy and safety, in comparison with imipenem/cilastatin in phase 3 clinical trials, for complicated intra-abdominal infection (cIAI). The present study comprised a multicentre, open-label, randomized study of TGC vs. ceftriaxone plus metronidazole (CTX/MET) for the treatment of patients with cIAI. Eligible subjects were randomized (1:1) to receive either an initial dose of TGC (100 mg) followed by 50 mg every 12 h or CTX (2 g once daily) plus MET (1-2 g daily), for 4-14 days. The primary endpoint was the clinical response in the clinically evaluable (CE) population at the test of cure (TOC) assessment. Of 473 randomized subjects, 376 were CE. Among these, clinical cure rates were 70.4% (133/189) with TGC vs. 74.3% (139/187) with CTX/MET (95% CI -13.1 to 5.1; p 0.009 for non-inferiority). Clinical cure rates for subjects with Acute Physiological and Chronic Health Evaluation II scores > or =10 were 56.8% (21/37) with TGC vs. 58.3% (21/36) with CTX/MET. The microbiologic response was similar between the two treatment arms, with microbiological eradication at TOC achieved in 68.1% (94/138) of TGC-treated subjects and 71.5% (98/137) of CTX/MET-treated subjects. (The most frequently reported adverse events (AEs) for both treatment arms were nausea (TGC, 38.6% vs CTX/MET, 27.7%) and vomiting (TGC, 23.3% vs CTX/MET, 17.7%). Overall discontinuation rates as a result of an AE were 8.9% and 4.8% in TGC- and comparator-treated subjects, respectively. The results obtained in the present study demonstrate that TGC monotherapy is non-inferior to a combination regimen of CTX/MET with respect to treating subjects with cIAI. PMID:20670293

  4. Entanglement of phase-random states

    NASA Astrophysics Data System (ADS)

    Nakata, Yoshifumi; Turner, Peter; Murao, Mio

    2014-12-01

    In order to study generic properties of time-evolving states by time-independent Hamiltonian dynamics, we introduce phase-random states, an ensemble of pure states with fixed amplitudes and uniformly distributed phases in a fixed basis. We compute the average amount of entanglement of phase-random states analytically, and show that the average can be extremely large when the amplitudes are equal and the basis is separable. We also study implications on Hamiltonian dynamics, in particular the realization of the canonical state in a subsystem.

  5. Phase Transitions on Random Lattices: How Random is Topological Disorder?

    NASA Astrophysics Data System (ADS)

    Barghathi, Hatem; Vojta, Thomas

    2015-03-01

    We study the effects of topological (connectivity) disorder on phase transitions. We identify a broad class of random lattices whose disorder fluctuations decay much faster with increasing length scale than those of generic random systems, yielding a wandering exponent of ω = (d - 1) / (2 d) in d dimensions. The stability of clean critical points is thus governed by the criterion (d + 1) ν > 2 rather than the usual Harris criterion dν > 2 , making topological disorder less relevant than generic randomness. The Imry-Ma criterion is also modified, allowing first-order transitions to survive in all dimensions d > 1 . These results explain a host of puzzling violations of the original criteria for equilibrium and nonequilibrium phase transitions on random lattices. We discuss applications, and we illustrate our theory by computer simulations of random Voronoi and other lattices. This work was supported by the NSF under Grant Nos. DMR-1205803 and PHYS-1066293. We acknowledge the hospitality of the Aspen Center for Physics.

  6. Random-phase metasurfaces at optical wavelengths

    PubMed Central

    Pors, Anders; Ding, Fei; Chen, Yiting; Radko, Ilya P.; Bozhevolnyi, Sergey I.

    2016-01-01

    Random-phase metasurfaces, in which the constituents scatter light with random phases, have the property that an incident plane wave will diffusely scatter, hereby leading to a complex far-field response that is most suitably described by statistical means. In this work, we present and exemplify the statistical description of the far-field response, particularly highlighting how the response for polarised and unpolarised light might be alike or different depending on the correlation of scattering phases for two orthogonal polarisations. By utilizing gap plasmon-based metasurfaces, consisting of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications. Finally, by incorporating a certain correlation between scattering by neighbouring metasurface constituents new types of functionalities can be realised, such as a Lambertian reflector. PMID:27328635

  7. Random-phase metasurfaces at optical wavelengths.

    PubMed

    Pors, Anders; Ding, Fei; Chen, Yiting; Radko, Ilya P; Bozhevolnyi, Sergey I

    2016-01-01

    Random-phase metasurfaces, in which the constituents scatter light with random phases, have the property that an incident plane wave will diffusely scatter, hereby leading to a complex far-field response that is most suitably described by statistical means. In this work, we present and exemplify the statistical description of the far-field response, particularly highlighting how the response for polarised and unpolarised light might be alike or different depending on the correlation of scattering phases for two orthogonal polarisations. By utilizing gap plasmon-based metasurfaces, consisting of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications. Finally, by incorporating a certain correlation between scattering by neighbouring metasurface constituents new types of functionalities can be realised, such as a Lambertian reflector. PMID:27328635

  8. Random-phase metasurfaces at optical wavelengths

    NASA Astrophysics Data System (ADS)

    Pors, Anders; Ding, Fei; Chen, Yiting; Radko, Ilya P.; Bozhevolnyi, Sergey I.

    2016-06-01

    Random-phase metasurfaces, in which the constituents scatter light with random phases, have the property that an incident plane wave will diffusely scatter, hereby leading to a complex far-field response that is most suitably described by statistical means. In this work, we present and exemplify the statistical description of the far-field response, particularly highlighting how the response for polarised and unpolarised light might be alike or different depending on the correlation of scattering phases for two orthogonal polarisations. By utilizing gap plasmon-based metasurfaces, consisting of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications. Finally, by incorporating a certain correlation between scattering by neighbouring metasurface constituents new types of functionalities can be realised, such as a Lambertian reflector.

  9. Citalopram versus fluoxetine: a double-blind, controlled, multicentre, phase III trial in patients with unipolar major depression treated in general practice.

    PubMed

    Patris, M; Bouchard, J M; Bougerol, T; Charbonnier, J F; Chevalier, J F; Clerc, G; Cyran, C; Van Amerongen, P; Lemming, O; Høpfner Petersen, H E

    1996-06-01

    Two selective serotonin reuptake inhibitors (SSRIs), citalopram and fluoxetine, both at a daily dose of 20 mg, were compared in patients with unipolar major depression treated in general practice. This was a multicentre, double-blind, randomized trial carried out in France. The duration of treatment was 8 weeks. Patients were assessed by means of the Montgomery-Asberg Depression Rating Scale (MADRS), the 17 items Hamilton Depression Rating Scale (HAMD) and the investigator's Clinical Global Impressions (CGI), Observed and spontaneously reported adverse events were also recorded. A total of 357 patients of both sexes, aged between 21 and 73 years, entered the double-blind phase of the trial. A clear reduction of both the MADRS and the HAMD mean total scores was observed in both treatment groups with no statistically significant differences between treatments. Apart from back pain recorded more frequently in the citalopram group, no significant difference was found between the two treatment groups with regard to adverse events, and both citalopram and fluoxetine were considered to be well tolerated. It was concluded that citalopram was as effective as fluoxetine in the treatment of unipolar major depression. Citalopram showed an earlier onset of recovery than fluoxetine. PMID:8803650

  10. Random fields at a nonequilibrium phase transition.

    PubMed

    Barghathi, Hatem; Vojta, Thomas

    2012-10-26

    We study nonequilibrium phase transitions in the presence of disorder that locally breaks the symmetry between two equivalent macroscopic states. In low-dimensional equilibrium systems, such random-field disorder is known to have dramatic effects: it prevents spontaneous symmetry breaking and completely destroys the phase transition. In contrast, we show that the phase transition of the one-dimensional generalized contact process persists in the presence of random-field disorder. The ultraslow dynamics in the symmetry-broken phase is described by a Sinai walk of the domain walls between two different absorbing states. We discuss the generality and limitations of our theory, and we illustrate our results by large-scale Monte Carlo simulations. PMID:23215170

  11. Fast phase randomization via two-folds

    PubMed Central

    Jeffrey, M. R.

    2016-01-01

    A two-fold is a singular point on the discontinuity surface of a piecewise-smooth vector field, at which the vector field is tangent to the discontinuity surface on both sides. If an orbit passes through an invisible two-fold (also known as a Teixeira singularity) before settling to regular periodic motion, then the phase of that motion cannot be determined from initial conditions, and, in the presence of small noise, the asymptotic phase of a large number of sample solutions is highly random. In this paper, we show how the probability distribution of the asymptotic phase depends on the global nonlinear dynamics. We also show how the phase of a smooth oscillator can be randomized by applying a simple discontinuous control law that generates an invisible two-fold. We propose that such a control law can be used to desynchronize a collection of oscillators, and that this manner of phase randomization is fast compared with existing methods (which use fixed points as phase singularities), because there is no slowing of the dynamics near a two-fold. PMID:27118901

  12. Subcutaneous recombinant hirudin (HBW 023) versus intravenous sodium heparin in treatment of established acute deep vein thrombosis of the legs: a multicentre prospective dose-ranging randomized trial. International Multicentre Hirudin Study Group.

    PubMed

    Schiele, F; Lindgaerde, F; Eriksson, H; Bassand, J P; Wallmark, A; Hansson, P O; Grollier, G; Sjo, M; Moia, M; Camez, A; Smyth, V; Walker, M

    1997-05-01

    The aim of this multicentre, prospective, randomised, dose-ranging study was to compare the safety and efficacy of subcutaneous recombinant hirudin (HBW 023) against intravenous sodium heparin in acute lower limb deep venous thrombosis (DVT). Patients were randomized to treatment with either HBW 023 or heparin for 5 +/- 1 days. HBW 023 was given according to body-weight in three dose groups. Thromboembolic disease was assessed by phlebography and ventilation/perfusion (V/Q) scanning on Day 1 and Day 5 +/- 1. One hundred and fifty-five patients were enrolled, of these 121 were evaluable for efficacy analysis. Significantly fewer patients on HBW 023 developed new V/Q abnormalities during the treatment period, (p = 0.006). There was no difference between the groups in thrombus extension or regression, major bleeding complications or serious adverse events. There were significantly fewer findings of new V/Q mismatch after treatment with HBW 023, and anticoagulant control was superior in these patients. PMID:9184388

  13. Evolutionary Phase Transitions in Random Environments.

    PubMed

    Skanata, Antun; Kussell, Edo

    2016-07-15

    We present analytical results for long-term growth rates of structured populations in randomly fluctuating environments, which we apply to predict how cellular response networks evolve. We show that networks which respond rapidly to a stimulus will evolve phenotypic memory exclusively under random (i.e., nonperiodic) environments. We identify the evolutionary phase diagram for simple response networks, which we show can exhibit both continuous and discontinuous transitions. Our approach enables exact analysis of diverse evolutionary systems, from viral epidemics to emergence of drug resistance. PMID:27472146

  14. Evolutionary Phase Transitions in Random Environments

    NASA Astrophysics Data System (ADS)

    Skanata, Antun; Kussell, Edo

    2016-07-01

    We present analytical results for long-term growth rates of structured populations in randomly fluctuating environments, which we apply to predict how cellular response networks evolve. We show that networks which respond rapidly to a stimulus will evolve phenotypic memory exclusively under random (i.e., nonperiodic) environments. We identify the evolutionary phase diagram for simple response networks, which we show can exhibit both continuous and discontinuous transitions. Our approach enables exact analysis of diverse evolutionary systems, from viral epidemics to emergence of drug resistance.

  15. Efficiency of Hyaloglide in the prevention of the recurrence of adhesions after tenolysis of flexor tendons in zone II: a randomized, controlled, multicentre clinical trial.

    PubMed

    Riccio, M; Battiston, B; Pajardi, G; Corradi, M; Passaretti, U; Atzei, A; Altissimi, M; Vaienti, L; Catalano, F; Del Bene, M; Fasolo, P; Ceruso, M; Luchetti, R; Landi, A

    2010-02-01

    Hyaloglide is a hyaluronan-based gel based on a novel auto-crosslinked technology designed to reduce postsurgical adhesions. Its efficacy was assessed in a multicentred randomized controlled trial comparing the results of flexor tenolysis in zone 2 following failed flexor tendon repairs. In the control group a standard release was performed. In the treated group, Hyaloglide was applied into the flexor sheath and around the site of tenolysis. Forty-five patients, 19 controls and 26 treated with Hyaloglide, were enrolled in 13 centres. All the patients were evaluated at 30, 60, 90 and 180 days after surgery by testing Total Active Motion, Quick-DASH questionnaire and number of working days lost after surgery. Patients in the Hyaloglide group had a statistically better recovery of finger motion at all time intervals and returned earlier to work and daily activities. The use of Hyaloglide did not appear to increase the complication rate. PMID:19710086

  16. Faddeev random-phase approximation for molecules

    SciTech Connect

    Degroote, Matthias; Van Neck, Dimitri; Barbieri, Carlo

    2011-04-15

    The Faddeev random-phase approximation is a Green's function technique that makes use of Faddeev equations to couple the motion of a single electron to the two-particle-one-hole and two-hole-one-particle excitations. This method goes beyond the frequently used third-order algebraic diagrammatic construction method: all diagrams involving the exchange of phonons in the particle-hole and particle-particle channel are retained, but the phonons are now described at the level of the random-phase approximation, which includes ground-state correlations, rather than at the Tamm-Dancoff approximation level, where ground-state correlations are excluded. Previously applied to atoms, this paper presents results for small molecules at equilibrium geometry.

  17. Random phase textures: theory and synthesis.

    PubMed

    Galerne, Bruno; Gousseau, Yann; Morel, Jean-Michel

    2011-01-01

    This paper explores the mathematical and algorithmic properties of two sample-based texture models: random phase noise (RPN) and asymptotic discrete spot noise (ADSN). These models permit to synthesize random phase textures. They arguably derive from linearized versions of two early Julesz texture discrimination theories. The ensuing mathematical analysis shows that, contrarily to some statements in the literature, RPN and ADSN are different stochastic processes. Nevertheless, numerous experiments also suggest that the textures obtained by these algorithms from identical samples are perceptually similar. The relevance of this study is enhanced by three technical contributions providing solutions to obstacles that prevented the use of RPN or ADSN to emulate textures. First, RPN and ADSN algorithms are extended to color images. Second, a preprocessing is proposed to avoid artifacts due to the nonperiodicity of real-world texture samples. Finally, the method is extended to synthesize textures with arbitrary size from a given sample. PMID:20550995

  18. Double random phase encoding using phase reservation and compression

    NASA Astrophysics Data System (ADS)

    Chen, Wen; Chen, Xudong

    2014-02-01

    In recent years, various studies have been conducted to illustrate the vulnerability of double random phase encoding (DRPE). In this paper, we propose a novel method via phase reservation and compression to enhance DRPE security. Only a compressed phase distribution is available in the CCD plane, and the amplitude component is not available or requested for optical decryption. Since only noise-like distributions can be obtained by using the correct security keys during optical decryption, a nonlinear correlation algorithm is further applied for authenticating the decrypted image. It is demonstrated that valid conditions for attack algorithms are broken and high security can be achieved for the DRPE system.

  19. The addition of sirolimus to the graft-versus-host disease prophylaxis regimen in reduced intensity allogeneic stem cell transplantation for lymphoma: a multicentre randomized trial.

    PubMed

    Armand, Philippe; Kim, Haesook T; Sainvil, Marie-Michele; Lange, Paulina B; Giardino, Angela A; Bachanova, Veronika; Devine, Steven M; Waller, Edmund K; Jagirdar, Neera; Herrera, Alex F; Cutler, Corey; Ho, Vincent T; Koreth, John; Alyea, Edwin P; McAfee, Steven L; Soiffer, Robert J; Chen, Yi-Bin; Antin, Joseph H

    2016-04-01

    Inhibition of the mechanistic target of rapamycin (mTOR) pathway has clinical activity in lymphoma. The mTOR inhibitor sirolimus has been used in the prevention and treatment of graft-versus-host disease (GVHD) after allogeneic haematopoietic stem cell transplantation (HSCT). A retrospective study suggested that patients with lymphoma undergoing reduced intensity conditioning (RIC) HSCT who received sirolimus as part of their GVHD prophylaxis regimen had a lower rate of relapse. We therefore performed a multicentre randomized trial comparing tacrolimus, sirolimus and methotrexate to standard regimens in adult patients undergoing RIC HSCT for lymphoma in order to assess the possible benefit of sirolimus on HSCT outcome. 139 patients were randomized. There was no difference overall in 2-year overall survival, progression-free survival, relapse, non-relapse mortality or chronic GVHD. However, the sirolimus-containing arm had a significantly lower incidence of grade II-IV acute GVHD (9% vs. 25%, P = 0·015), which was more marked for unrelated donor grafts. In conclusion, the addition of sirolimus for GVHD prophylaxis in RIC HSCT is associated with no increased overall toxicity and a lower risk of acute GVHD, although it does not improve survival; this regimen is an acceptable option for GVHD prevention in RIC HSCT. This trial is registered at clinicaltrials.gov (NCT00928018). PMID:26729448

  20. Multicentric neoadjuvant pilot Phase II study of cetuximab combined with docetaxel in operable triple negative breast cancer.

    PubMed

    Nabholtz, J M; Chalabi, N; Radosevic-Robin, N; Dauplat, M M; Mouret-Reynier, M A; Van Praagh, I; Servent, V; Jacquin, J P; Benmammar, K E; Kullab, S; Bahadoor, M R K; Kwiatkowski, F; Cayre, A; Abrial, C; Durando, X; Bignon, Y J; Chollet, P; Penault-Llorca, F

    2016-05-01

    Systemic therapy for triple negative breast cancer (TNBC) is mostly based upon chemotherapy. Epithelial Growth Factor Receptor (EGFR) is overexpressed in around 50% of TNBC and may play a role in its pathogenesis. Consequently, we performed a multicentric pilot Phase II neoadjuvant trial of cetuximab (anti-EGFR antibody) combined with docetaxel for patients with operable, Stage II-III TNBC. Therapy consisted of weekly cetuximab (first infusion: 400 mg/m(2), then 250 mg/m(2)) combined with six cycles of docetaxel (T: 100 mg/m(2)) q.3 weeks. Subsequently, all patients underwent surgery. The primary endpoint was pathological complete response (pCR) while clinical response, toxicity and ancillary studies were secondary endpoints. Paraffin-embedded and frozen tumor samples were systematically collected in order to identify predictive biomarkers of efficacy and resistance. From a total of 35 accrued patients, 25 were assessable for pathologic response. The pCR rate was 24% [95% CI: 7.3-40.7]. Complete clinical response rate (cCR) was observed in 22% of cases. Conservative surgery was performed in 75% of patients. Toxicity, mostly cutaneous and hematologic, was manageable. The pre-therapy ratio between CD8+ and FOXP3+ tumor-infiltrating lymphocytes equal or higher than 2.75 was predictive of pCR: 43% versus 0%, p = 0.047. Cetuximab in combination with docetaxel displays a modest activity, but acceptable toxicity as neoadjuvant therapy of operable TNBC. Similarly to previous observations using panitumumab, another anti-EGFR antibody, the immune component of the tumor microenvironment may play an important role in predicting TNBC response to the neoadjuvant therapy. PMID:26649807

  1. Erythropoietin in amyotrophic lateral sclerosis: a multicentre, randomised, double blind, placebo controlled, phase III study

    PubMed Central

    Lauria, Giuseppe; Dalla Bella, Eleonora; Antonini, Giovanni; Borghero, Giuseppe; Capasso, Margherita; Caponnetto, Claudia; Chiò, Adriano; Corbo, Massimo; Eleopra, Roberto; Fazio, Raffaella; Filosto, Massimiliano; Giannini, Fabio; Granieri, Enrico; La Bella, Vincenzo; Logroscino, Giancarlo; Mandrioli, Jessica; Mazzini, Letizia; Monsurrò, Maria Rosaria; Mora, Gabriele; Pietrini, Vladimiro; Quatrale, Rocco; Rizzi, Romana; Salvi, Fabrizio; Siciliano, Gabriele; Sorarù, Gianni; Volanti, Paolo; Tramacere, Irene; Filippini, Graziella

    2015-01-01

    Objective To assess the efficacy of recombinant human erythropoietin (rhEPO) in amyotrophic lateral sclerosis (ALS). Methods Patients with probable laboratory-supported, probable or definite ALS were enrolled by 25 Italian centres and randomly assigned (1:1) to receive intravenous rhEPO 40 000 IU or placebo fortnightly as add-on treatment to riluzole 100 mg daily for 12 months. The primary composite outcome was survival, tracheotomy or >23 h non-invasive ventilation (NIV). Secondary outcomes were ALSFRS-R, slow vital capacity (sVC) and quality of life (ALSAQ-40) decline. Tolerability was evaluated analysing adverse events (AEs) causing withdrawal. The randomisation sequence was computer-generated by blocks, stratified by centre, disease severity (ALSFRS-R cut-off score of 33) and onset (spinal or bulbar). The main outcome analysis was performed in all randomised patients and by intention-to-treat for the entire population and patients stratified by severity and onset. The study is registered, EudraCT 2009-016066-91. Results We randomly assigned 208 patients, of whom 5 (1 rhEPO and 4 placebo) withdrew consent and 3 (placebo) became ineligible (retinal thrombosis, respiratory insufficiency, SOD1 mutation) before receiving treatment; 103 receiving rhEPO and 97 placebo were eligible for analysis. At 12 months, the annualised rate of death (rhEPO 0.11, 95% CI 0.06 to 0.20; placebo: 0.08, CI 0.04 to 0.17), tracheotomy or >23 h NIV (rhEPO 0.16, CI 0.10 to 0.27; placebo 0.18, CI 0.11 to 0.30) did not differ between groups, also after stratification by onset and ALSFRS-R at baseline. Withdrawal due to AE was 16.5% in rhEPO and 8.3% in placebo. No differences were found for secondary outcomes. Conclusions RhEPO 40 000 IU fortnightly did not change the course of ALS. PMID:25595151

  2. Four-phase rhinomanometry: a multicentric retrospective analysis of 36,563 clinical measurements.

    PubMed

    Vogt, Klaus; Wernecke, Klaus-Dieter; Behrbohm, Hans; Gubisch, Wolfgang; Argale, Mara

    2016-05-01

    Rhinomanometry can still be considered as the standard technique for the objective assessment of the ventilatory function of the nose. Reliable technical requirements are given by fast digital sensors and modern information technology. However, the xyimaging of the pressure-flow relation typically shows loops as a sign of hysteresis, with the need for resolution of the breath in four phases. The three pillars of 4-phase rhinomanometry (4PR) are the replacement of estimations by measurements, the introduction of parameters related to the subjective sensing of obstruction, and the graphical information regarding the disturbed function of the nasal valve. In a meta-analysis of 36,563 clinical measurements, we analyze the errors of the "classic" parameters (flow in 150 Pa) and reject the further use of these parameters as obsolete, because they correspond to an inaccurate estimation rather than proper measurement. In a pre-study of 1580 measurements, the logarithmic effective resistance (Reff) was found to have the highest correlation with values obtained from a visual analog scale. Next, we classify the inspiratory effective resistance in 20,069 measurements without treatment and 16,494 measurements after decongestion with xylometazoline 0.1 % spray in 20 % percentiles. The gradation of obstruction delivers not only "normal" values but also indications for the severity of the obstruction in adult Caucasian noses. Adoption of the distribution for the growing nose and analysis of the total nasal resistance is addressed, and typical findings of nasal valve phenomena are outlined. PMID:26198284

  3. Impact of rapid antigen detection testing on antibiotic prescription in acute pharyngitis in adults. FARINGOCAT STUDY: a multicentric randomized controlled trial

    PubMed Central

    2010-01-01

    Background Acute pharyngitis is one of the most frequent consultations to the general practitioner and in most of the cases an antibiotic is prescribed in primary care in Spain. Bacterial etiology, mainly by group A beta-hemolytic streptococcus (GABHS), accounts for 10-20% of all these infections in adults. The purpose of this study is to assess the impact of rapid antigen detection testing (RADT) to identify GABHS in acute pharyngitis on the utilization of antibiotics in primary care. Methods/design Multicentric randomized controlled trial in which antibiotic prescription between two groups of patients with acute pharyngitis will be compared. The trial will include two arms, a control and an intervention group in which RADT will be performed. The primary outcome measure will be the proportion of inappropriate antibiotic prescription in each group. Two hundred seventy-six patients are required to detect a reduction in antibiotic prescription from 85% in the control group to 75% in the intervention group with a power of 90% and a level of significance of 5%. Secondary outcome measures will be specific antibiotic treatment, antibiotic resistance rates, secondary effects, days without working, medical visits during the first month and patient satisfaction. Discussion The implementation of RADT would allow a more rational use of antibiotics and would prevent adverse effects of antibiotics, emergence of antibiotic resistance and the growth of inefficient health expenses. Trial registration ISRCTN23587778 PMID:20331895

  4. Armodafinil versus Modafinil in Patients of Excessive Sleepiness Associated with Shift Work Sleep Disorder: A Randomized Double Blind Multicentric Clinical Trial

    PubMed Central

    Tembe, D. V.; Dhavale, A.; Desai, H.; Mane, D. N.; Raut, S. K.; Dhingra, G.; Sardesai, U.; Saoji, S.; Rohra, M.; Shinde, V. G.; Padsalge, M.; Paliwal, A.; Abbasi, K.; Devnani, P.; Papinwar, S.; Phadke, S.; Mehta, H.; Bhailume, V.

    2011-01-01

    Aim. To compare the efficacy and safety of armodafinil, the R-enantiomer of modafinil, with modafinil in patients of shift work sleep disorder (SWSD). Material and Methods. This was a 12-week, randomized, comparative, double-blind, multicentric, parallel-group study in 211 patients of SWSD, receiving armodafinil (150 mg) or modafinil (200 mg) one hour prior to the night shift. Outcome Measures. Efficacy was assessed by change in stanford sleepiness score (SSS) by at least 2 grades (responder) and global assessment for efficacy. Safety was assessed by incidence of adverse events, change in laboratory parameters, ECG, and global assessment of tolerability. Results. Both modafinil and armodafinil significantly improved sleepiness mean grades as compared to baseline (P < .0001). Responder rates with armodafinil (72.12%) and modafinil (74.29%) were comparable (P = .76). Adverse event incidences were comparable. Conclusion. Armodafinil was found to be safe and effective in the treatment of SWSD in Indian patients. The study did not demonstrate any difference in efficacy and safety of armodafinil 150 mg and modafinil 200 mg. PMID:21766023

  5. Liraglutide efficacy and action in non-alcoholic steatohepatitis (LEAN): study protocol for a phase II multicentre, double-blinded, randomised, controlled trial

    PubMed Central

    Armstrong, Matthew J; Barton, Darren; Gaunt, Piers; Hull, Diana; Guo, Kathy; Stocken, Deborah; Gough, Stephen C L; Tomlinson, Jeremy W; Brown, Rachel M; Hübscher, Stefan G; Newsome, Philip N

    2013-01-01

    Introduction Non-alcoholic steatohepatitis (NASH) is now the commonest cause of chronic liver disease. Despite this, there are no universally accepted pharmacological therapies for NASH. Liraglutide (Victoza), a human glucagon-like peptide-1 (GLP-1) analogue, has been shown to improve weight loss, glycaemic control and liver enzymes in type 2 diabetes. There is currently a lack of prospective-controlled studies investigating the efficacy of GLP-1 analogues in patients with NASH. Methods and analysis Liraglutide efficacy and action in NASH (LEAN) is a phase II, multicentre, double-blinded, placebo-controlled, randomised clinical trial designed to investigate whether a 48-week treatment with 1.8 mg liraglutide will result in improvements in liver histology in patients with NASH. Adult, overweight (body mass index ≥25 kg/m2) patients with biopsy-confirmed NASH were assessed for eligibility at five recruitment centres in the UK. Patients who satisfied the eligibility criteria were randomly assigned (1:1) to receive once-daily subcutaneous injections of either 1.8 mg liraglutide or liraglutide-placebo (control). Using A'Hern's single stage phase II methodology (significance level 0.05; power 0.90) and accounting for an estimated 20% withdrawal rate, a minimum of 25 patients were randomised to each treatment group. The primary outcome measure will be centrally assessed using an intention-to-treat analysis of the proportion of evaluable patients achieving an improvement in liver histology between liver biopsies at baseline and after 48 weeks of treatment. Histological improvement will be defined as a combination of the disappearance of active NASH and no worsening in fibrosis. Ethics and dissemination The protocol was approved by the National Research Ethics Service (East Midlands—Northampton committee; 10/H0402/32) and the Medicines and Healthcare products Regulatory Agency. Recruitment into the LEAN started in August 2010 and ended in May 2013, with 52

  6. A multicentre, prospective, randomized, controlled trial comparing EVARREST™ fibrin sealant patch to standard of care in controlling bleeding following elective hepatectomy: anatomic versus non-anatomic resection

    PubMed Central

    Koea, Jonathan B.; Batiller, Jonathan; Aguirre, Nicolas; Shen, Jessica; Kocharian, Richard; Bochicchio, Grant; Garden, O. James

    2016-01-01

    Background This multicentre, randomized clinical trial assessed the safety and effectiveness of the EVARREST™ Fibrin Sealant Patch (FP) in treating parenchymal bleeding following anatomic and non-anatomic liver resections. Methods One hundred and two patients were stratified according to the type of hepatic resection (anatomic/non-anatomic), and randomized (1:1) after identification of an appropriate bleeding site, to FP vs Standard of Care (SoC, manual compression ± topical haemostat). The primary endpoint was haemostasis at 4 min from bleeding site identification with no re-bleeding requiring re-treatment. Results The FP was superior in achieving haemostasis at 4 min (96%, 48/50) to SoC (46%, 24/52; p < 0.001). Stratification for resection type showed treatment differences for primary endpoint for anatomic (24/25 FP vs 13/23 SoC; p = 0.001) and non-anatomic liver resections (24/25FP vs 11/29 SoC; p < 0.001). Adverse events related to the study procedure were reported in 40/50 patients (80%) in the FP group and 43/52 patients (83%) in the SoC group. One (2%) adverse event (infected intra-abdominal fluid collection) was possibly related to study treatment. Conclusion This clinical trial confirms that the FP is safe and highly effective in controlling parenchymal bleeding following hepatectomy regardless of the type of resection. ClinicalTrials.gov NCT01993888. PMID:27017161

  7. Implementation phase of a multicentre prehospital telemedicine system to support paramedics: feasibility and possible limitations

    PubMed Central

    2013-01-01

    Background Legal regulations often limit the medical care that paramedics can provide. Telemedical solutions could overcome these limitations by remotely providing expert support. Therefore, a mobile telemedicine system to support paramedics was developed. During the implementation phase of this system in four German emergency medical services (EMS), the feasibility and possible limitations of this system were evaluated. Methods After obtaining ethical approval and providing a structured training program for all medical professionals, the system was implemented on three paramedic-staffed ambulances on August 1st, 2012. Two more ambulances were included subsequently during this month. The paramedics could initiate a consultation with EMS physicians at a teleconsultation centre. Telemedical functionalities included audio communication, real-time vital data transmission, 12-lead electrocardiogram, picture transmission on demand, and video streaming from a camera embedded into the ceiling of each ambulance. After each consultation, telephone-based debriefings were conducted. Data were retrieved from the documentation protocols of the teleconsultation centre and the EMS. Results During a one month period, teleconsultations were conducted during 35 (11.8%) of 296 emergency missions with a mean duration of 24.9 min (SD 12.5). Trauma, acute coronary syndromes, and circulatory emergencies represented 20 (57%) of the consultation cases. Diagnostic support was provided in 34 (97%) cases, and the administration of 50 individual medications, including opioids, was delegated by the teleconsultation centre to the paramedics in 21 (60%) missions (range: 1–7 per mission). No medical complications or negative interpersonal effects were reported. All applications functioned as expected except in one case in which the connection failed due to the lack of a viable mobile network. Conclusion The feasibility of the telemedical approach was demonstrated. Teleconsultation enabled early

  8. Random phase-shifting interferometry based on independent component analysis

    NASA Astrophysics Data System (ADS)

    Xu, Xiaofei; Lu, Xiaoxu; Tian, Jindong; Shou, Junwei; Zheng, Dejin; Zhong, Liyun

    2016-07-01

    In random phase-shifting interferometry, a novel phase retrieval algorithm is proposed based on the independent component analysis (ICA). By performing the recombination of pixel position, a sequence of phase-shifting interferograms with random phase shifts are decomposed into a group of mutual independent components, and then the background and the measured phase of interferogram can obtained with a simple arctangent operation. Compared with the conventional advanced iterative algorithm (AIA) with high accuracy, both the simulation and the experimental results demonstrate that the proposed ICA algorithm reveals high accuracy, rapid convergence, and good noise-tolerance in random phase-shifting interferometry.

  9. Phase Structure of the Random Zq Models in 2D

    NASA Astrophysics Data System (ADS)

    Sasamoto, T.; Nishimori, H.

    We discuss the phase diagram of the random Zq models in two dimensions. It is argued that, when q is large enough, there exist three phases in the phase diagram with two axes being the temperature and the strength of randomness. Our conlusions are derived based on the application of the duality arguments for random systems, which have been formulated recently by Maillard et al.

  10. Self-Consistent Random Phase Approximation

    NASA Astrophysics Data System (ADS)

    Rohr, Daniel; Hellgren, Maria; Gross, E. K. U.

    2012-02-01

    We report self-consistent Random Phase Approximation (RPA) calculations within the Density Functional Theory. The calculations are performed by the direct minimization scheme for the optimized effective potential method developed by Yang et al. [1]. We show results for the dissociation curve of H2^+, H2 and LiH with the RPA, where the exchange correlation kernel has been set to zero. For H2^+ and H2 we also show results for RPAX, where the exact exchange kernel has been included. The RPA, in general, over-correlates. At intermediate distances a maximum is obtained that lies above the exact energy. This is known from non-self-consistent calculations and is still present in the self-consistent results. The RPAX energies are higher than the RPA energies. At equilibrium distance they accurately reproduce the exact total energy. In the dissociation limit they improve upon RPA, but are still too low. For H2^+ the RPAX correlation energy is zero. Consequently, RPAX gives the exact dissociation curve. We also present the local potentials. They indicate that a peak at the bond midpoint builds up with increasing bond distance. This is expected for the exact KS potential.[4pt] [1] W. Yang, and Q. Wu, Phys. Rev. Lett., 89, 143002 (2002)

  11. Randomized, multicentre assessment of the efficacy and safety of ASAQ – a fixed-dose artesunate-amodiaquine combination therapy in the treatment of uncomplicated Plasmodium falciparum malaria

    PubMed Central

    Ndiaye, Jean Louis; Randrianarivelojosia, Milijaona; Sagara, Issaka; Brasseur, Philippe; Ndiaye, Ibrahima; Faye, Babacar; Randrianasolo, Laurence; Ratsimbasoa, Arsène; Forlemu, Doris; Moor, Vicky Ama; Traore, Aminata; Dicko, Yahia; Dara, Niawanlou; Lameyre, Valérie; Diallo, Mouctar; Djimde, Abdoulaye; Same-Ekobo, Albert; Gaye, Oumar

    2009-01-01

    Background The use of artemisinin derivative-based combination therapy (ACT) such as artesunate plus amodiaquine is currently recommended for the treatment of uncomplicated Plasmodium falciparum malaria. Fixed-dose combinations are more adapted to patients than regimens involving multiple tablets and improve treatment compliance. A fixed-dose combination of artesunate + amodiaquine (ASAQ) was recently developed. To assess the efficacy and safety of this new combination and to define its optimum dosage regimen (once or twice daily) in the treatment of uncomplicated P. falciparum malaria, a multicentre clinical study was conducted. Methods A multicentre, randomized, controlled, investigator-blinded, parallel-group study was conducted in five African centers in Cameroon, Madagascar, Mali and Senegal from March to December 2006. Efficacy and safety of ASAQ were assessed compared to those of artemether + lumefantrine (AL). The WHO protocol with a 28-day follow-up for assessing the drug therapeutic efficacy was used. Patients suffering from uncomplicated P. falciparum malaria were randomized to receive ASAQ orally once daily (ASAQ1), ASAQ twice daily (ASAQ2) or AL twice daily (AL) for three days. The primary outcome was PCR-corrected parasitological cure rate and clinical response. Results Of 941 patients initially randomized and stratified into two age groups (<5 years, and ≥5 years), 936 (99.5%) were retained for the intent to treat (ITT) analysis, and 859 (91.3%) patients for the per protocol (PP) analysis. Among ITT population, up to D28, PCR-corrected adequate parasitological and clinical response rates were 95.2% in the ASAQ1 group, 94.9% in the ASAQ2 group and 95.5% in the AL group. Moreover, the cure rate evaluated among PP population was ≥98.5% in both ASAQ therapeutic arms. Therapeutic response rates did not display any significant differences between age groups or between one geographical site and another. Altogether, this demonstrates the non

  12. Optimization of ventilator setting by flow and pressure waveforms analysis during noninvasive ventilation for acute exacerbations of COPD: a multicentric randomized controlled trial

    PubMed Central

    2011-01-01

    Introduction The analysis of flow and pressure waveforms generated by ventilators can be useful in the optimization of patient-ventilator interactions, notably in chronic obstructive pulmonary disease (COPD) patients. To date, however, a real clinical benefit of this approach has not been proven. Methods The aim of the present randomized, multi-centric, controlled study was to compare optimized ventilation, driven by the analysis of flow and pressure waveforms, to standard ventilation (same physician, same initial ventilator setting, same time spent at the bedside while the ventilator screen was obscured with numerical data always available). The primary aim was the rate of pH normalization at two hours, while secondary aims were changes in PaCO2, respiratory rate and the patient's tolerance to ventilation (all parameters evaluated at baseline, 30, 120, 360 minutes and 24 hours after the beginning of ventilation). Seventy patients (35 for each group) with acute exacerbation of COPD were enrolled. Results Optimized ventilation led to a more rapid normalization of pH at two hours (51 vs. 26% of patients), to a significant improvement of the patient's tolerance to ventilation at two hours, and to a higher decrease of PaCO2 at two and six hours. Optimized ventilation induced physicians to use higher levels of external positive end-expiratory pressure, more sensitive inspiratory triggers and a faster speed of pressurization. Conclusions The analysis of the waveforms generated by ventilators has a significant positive effect on physiological and patient-centered outcomes during acute exacerbation of COPD. The acquisition of specific skills in this field should be encouraged. Trial registration ClinicalTrials.gov NCT01291303. PMID:22115190

  13. A randomized, double-blind, placebo-controlled, multicentre study to assess haemodynamic effects of serelaxin in patients with acute heart failure

    PubMed Central

    Ponikowski, Piotr; Mitrovic, Veselin; Ruda, Mikhail; Fernandez, Alberto; Voors, Adriaan A.; Vishnevsky, Alexander; Cotter, Gad; Milo, Olga; Laessing, Ute; Zhang, Yiming; Dahlke, Marion; Zymlinski, Robert; Metra, Marco

    2014-01-01

    Aims The aim of this study was to evaluate the haemodynamic effects of serelaxin (30 µg/kg/day 20-h infusion and 4-h post-infusion period) in patients with acute heart failure (AHF). Methods and results This double-blind, multicentre study randomized 71 AHF patients with pulmonary capillary wedge pressure (PCWP) ≥18 mmHg, systolic blood pressure (BP) ≥115 mmHg, and estimated glomerular filtration rate ≥30 mL/min/1.73 m2 to serelaxin (n = 34) or placebo (n = 37) within 48 h of hospitalization. Co-primary endpoints were peak change from baseline in PCWP and cardiac index (CI) during the first 8 h of infusion. Among 63 patients eligible for haemodynamic analysis (serelaxin, n = 32; placebo, n = 31), those treated with serelaxin had a significantly higher decrease in peak PCWP during the first 8 h of infusion (difference vs. placebo: −2.44 mmHg, P = 0.004). Serelaxin showed no significant effect on the peak change in CI vs. placebo. Among secondary haemodynamic endpoints, a highly significant reduction in pulmonary artery pressure (PAP) was observed throughout the serelaxin infusion (largest difference in mean PAP vs. placebo: −5.17 mmHg at 4 h, P < 0.0001). Right atrial pressure, systemic/pulmonary vascular resistance, and systolic/diastolic BP decreased from baseline with serelaxin vs. placebo and treatment differences reached statistical significance at some time points. Serelaxin administration improved renal function and decreased N-terminal pro-brain natriuretic peptide levels vs. placebo. Treatment with serelaxin was well tolerated with no apparent safety concerns. Conclusion The haemodynamic effects of serelaxin observed in the present study provide plausible mechanistic support for improvement in signs and symptoms of congestion observed with this agent in AHF patients. ClinicalTrials.gov identifier NCT01543854. PMID:24255129

  14. TOURNIQUET VERSUS NO TOURNIQUET USE IN KNEE VIDEOARTHROSCOPY: A MULTICENTRIC, PROSPECTIVE, DOUBLE-BLIND, RANDOMIZED CLINICAL TRIAL

    PubMed Central

    Júnior, Lúcio Honório de Carvalho; Soares, Luiz Fernando Machado; Gonçalves, Matheus Braga Jacques; Gomes, Tiago Pinto de Oliveira; Oliveira, Juraci Rosa de; Coelho, Mauro Gualberto; Santos, Rogério Luciano dos; Andrade, Marco Antônio Percope de; Silva, Guilherme de Lima e; Novais, Eduardo Nilo Vasconcelos

    2015-01-01

    To evaluate whether, by using an arthropump (irrigation equipment with pressure sensor), pneumatic tourniquet use could interfere with the duration of surgery, recovery of movement and joint volume in patients who underwent knee videoarthroscopy for partial meniscectomy. Methods: 103 patients divided randomly into two groups regarding use or nonuse of a pneumatic tourniquet were evaluated in five different centers by seven different surgeons. The variables were evaluated during the surgery and seven days after the operation. Results: No statistically significant differences were found among any of the variables studied. Conclusion: There are no reasons that would either justify or discredit tourniquet use in this specific situation. PMID:27022588

  15. Randomized multicentre trial of gadoxetic acid-enhanced MRI versus conventional MRI or CT in the staging of colorectal cancer liver metastases

    PubMed Central

    Zech, C J; Korpraphong, P; Huppertz, A; Denecke, T; Kim, M-J; Tanomkiat, W; Jonas, E; Ba-Ssalamah, A

    2014-01-01

    Background This multicentre international randomized trial compared the impact of gadoxetic acid-enhanced magnetic resonance imaging (MRI), MRI with extracellular contrast medium (ECCM-MRI) and contrast-enhanced computed tomography (CE-CT) as a first-line imaging method in patients with suspected colorectal cancer liver metastases (CRCLM). Methods Between October 2008 and September 2010, patients with suspected CRCLM were randomized to one of the three imaging modalities. The primary endpoint was the proportion of patients for whom further imaging after initial imaging was required for a confident diagnosis. Secondary variables included confidence in the therapeutic decision, intraoperative deviations from the initial imaging-based surgical plan as a result of additional operative findings, and diagnostic efficacy of the imaging modalities versus intraoperative and pathological extent of the disease. Results A total of 360 patients were enrolled. Efficacy was analysed in 342 patients (118, 112 and 112 with gadoxetic acid-enhanced MRI, ECCM-MRI and CE-CT respectively as the initial imaging procedure). Further imaging was required in 0 of 118, 19 (17·0 per cent) of 112 and 44 (39·3 per cent) of 112 patients respectively (P < 0·001). Diagnostic confidence was high or very high in 98·3 per cent of patients for gadoxetic acid-enhanced MRI, 85·7 per cent for ECCM-MRI and 65·2 per cent for CE-CT. Surgical plans were changed during surgery in 28, 32 and 47 per cent of patients in the respective groups. Conclusion The diagnostic performance of gadoxetic acid-enhanced MRI was better than that of CE-CT and ECCM-MRI as the initial imaging modality. No further imaging was needed in the gadoxetic acid-enhanced MRI group and comparison of diagnostic efficacy parameters demonstrated the diagnostic superiority of gadoxetic acid-enhanced MRI. Registration number: NCT00764621( http://clinicaltrials.gov ); EudraCT number: 2008-000583-16 ( https://eudract.ema.europa.eu/ ). PMID

  16. Fusion and failure following anterior cervical plating with dynamic or rigid plates: 6-months results of a multi-centric, prospective, randomized, controlled study

    PubMed Central

    Stulik, Jan; Chrobok, Jan; Ruffing, Sabine; Drumm, Jörg; Sova, Laurentius; Kucera, Ravel; Vyskocil, Tomas; Steudel, Wolf Ingo

    2007-01-01

    Anterior cervical plate fixation is an approved surgical technique for cervical spine stabilization in the presence of anterior cervical instability. Rigid plate design with screws rigidly locked to the plate is widely used and is thought to provide a better fixation for the treated spinal segment than a dynamic design in which the screws may slide when the graft is settling. Recent biomechanical studies showed that dynamic anterior plates provide a better graft loading possibly leading to accelerated spinal fusion with a lower incidence of implant complications. This, however, was investigated in vitro and does not necessarily mean to be the case in vivo, as well. Thus, the two major aspects of this study were to compare the speed of bone fusion and the rate of implant complications using either rigid- or dynamic plates. The study design is prospective, randomized, controlled, and multi-centric, having been approved by respective ethic committees of all participating sites. One hundred and thirty-two patients were included in this study and randomly assigned to one of the two groups, both undergoing routine level-1- or level-2 anterior cervical discectomy with autograft fusion receiving either a dynamic plate with screws being locked in ap - position (ABC, Aesculap, Germany), or a rigid plate (CSLP, Synthes, Switzerland). Segmental mobility and implant complications were compared after 3- and 6 months, respectively. All measurements were performed by an independent radiologist. Mobility results after 6 months were available for 77 patients (43 ABC/34 CSLP). Mean segmental mobility for the ABC group was 1.7 mm at the time of discharge, 1.4 mm after 3 months, and 0.8 mm after 6 months. For the CSLP- group the measurements were 1.0, 1.8, and 1.7 mm, respectively. The differences of mean segmental mobility were statistically significant between both groups after 6 months (P = 0.02). Four patients of the CSLP-group demonstrated surgical hardware complications

  17. Treatment of severe, nonfulminant acute hepatitis B with lamivudine vs placebo: a prospective randomized double-blinded multicentre trial.

    PubMed

    Wiegand, J; Wedemeyer, H; Franke, A; Rößler, S; Zeuzem, S; Teuber, G; Wächtler, M; Römmele, U; Ruf, B; Spengler, U; Trautwein, C; Bock, C T; Fiedler, G M; Thiery, J; Manns, M P; Brosteanu, O; Tillmann, H L

    2014-10-01

    Acute hepatitis B virus (aHBV) infection can lead to fulminant liver failure, which likely is prevented by early lamivudine therapy. Even nonfulminant but severe acute hepatitis B can lead to significant morbidity and impaired quality of life. Therefore, lamivudine was evaluated in patients with severe aHBV in a placebo-controlled trial. Patients with severe aHBV infection (ALT >10× ULN, bilirubin >85 μm, prothrombin time >50%) were prospectively treated with lamivudine 100 mg/day or with placebo within 8 days after the diagnosis. The primary end point was time to bilirubin <34.2 μm. Secondary end points were time to clear HBsAg and HBV-DNA, development of anti-HBs and normalization of ALT. Eighteen cases were randomized to lamivudine, 17 to placebo. 94% of patients were hospitalized. No individual progressed to hepatic failure; all but one patient achieved the primary end point. Due to smaller than expected patient numbers, all study end points did not become statistically significant between treatment arms. Median time end points [in days] were bilirubin <34.2 μm (26.5 vs 32), ALT normalization (35 vs 48) and HBsAg clearance (48 vs 67) referring to earlier recovery under lamivudine, in contrast to loss of HBV-DNA (62 vs 54) and development of anti-HBs (119 vs 109). In all but two patients (one in every group), HBsAg clearance was reached in the study. Adverse events occurred more frequently during lamivudine therapy, but did not reach statistical significance. Lamivudine may ameliorate severe aHBV infection, but limited patient numbers prevented definite conclusions. PMID:24329913

  18. Intermittent Preventive Treatment of Malaria in Pregnancy with Mefloquine in HIV-Negative Women: A Multicentre Randomized Controlled Trial

    PubMed Central

    Abdulla, Salim; Accrombessi, Manfred; Aponte, John J.; Akerey-Diop, Daisy; Basra, Arti; Briand, Valérie; Capan, Meskure; Cot, Michel; Kabanywanyi, Abdunoor M.; Kleine, Christian; Kremsner, Peter G.; Macete, Eusebio; Mackanga, Jean-Rodolphe; Massougbodgi, Achille; Mayor, Alfredo; Nhacolo, Arsenio; Pahlavan, Golbahar; Ramharter, Michael; Rupérez, María; Sevene, Esperança; Vala, Anifa; Zoleko-Manego, Rella; Menéndez, Clara

    2014-01-01

    Background Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended by WHO to prevent malaria in African pregnant women. The spread of SP parasite resistance has raised concerns regarding long-term use for IPT. Mefloquine (MQ) is the most promising of available alternatives to SP based on safety profile, long half-life, and high efficacy in Africa. We evaluated the safety and efficacy of MQ for IPTp compared to those of SP in HIV-negative women. Methods and Findings A total of 4,749 pregnant women were enrolled in an open-label randomized clinical trial conducted in Benin, Gabon, Mozambique, and Tanzania comparing two-dose MQ or SP for IPTp and MQ tolerability of two different regimens. The study arms were: (1) SP, (2) single dose MQ (15 mg/kg), and (3) split-dose MQ in the context of long lasting insecticide treated nets. There was no difference on low birth weight prevalence (primary study outcome) between groups (360/2,778 [13.0%]) for MQ group and 177/1,398 (12.7%) for SP group; risk ratio [RR], 1.02 (95% CI 0.86–1.22; p = 0.80 in the ITT analysis). Women receiving MQ had reduced risks of parasitemia (63/1,372 [4.6%] in the SP group and 88/2,737 [3.2%] in the MQ group; RR, 0.70 [95% CI 0.51–0.96]; p = 0.03) and anemia at delivery (609/1,380 [44.1%] in the SP group and 1,110/2743 [40.5%] in the MQ group; RR, 0.92 [95% CI 0.85–0.99]; p = 0.03), and reduced incidence of clinical malaria (96/551.8 malaria episodes person/year [PYAR] in the SP group and 130/1,103.2 episodes PYAR in the MQ group; RR, 0.67 [95% CI 0.52–0.88]; p = 0.004) and all-cause outpatient attendances during pregnancy (850/557.8 outpatients visits PYAR in the SP group and 1,480/1,110.1 visits PYAR in the MQ group; RR, 0.86 [0.78–0.95]; p = 0.003). There were no differences in the prevalence of placental infection and adverse pregnancy outcomes between groups. Tolerability was poorer in the two MQ groups compared to SP

  19. Double random-phase encoding in the Fresnel domain.

    PubMed

    Situ, Guohai; Zhang, Jingjuan

    2004-07-15

    A lensless optical security system based on double random-phase encoding in the Fresnel domain is proposed. This technique can encrypt a primary image to random noise by use of two statistically independent random-phase masks in the input and transform planes, respectively. In this system the positions of the significant planes and the operation wavelength, as well as the phase codes, are used as keys to encrypt and recover the primary image. Therefore higher security is achieved. The sensitivity of the decrypted image to shifting along the propagation direction and to the wavelength are also investigated. PMID:15309826

  20. Ordering and phase transitions in random-field Ising systems

    NASA Technical Reports Server (NTRS)

    Maritan, Amos; Swift, Michael R.; Cieplak, Marek; Chan, Moses H. W.; Cole, Milton W.; Banavar, Jayanth R.

    1991-01-01

    An exact analysis of the Ising model with infinite-range interactions in a random field and a local mean-field theory in three dimensions is carried out leading to a phase diagram with several coexistence surfaces and lines of critical points. The results show that the phase diagram depends crucially on whether the distribution of random fields is symmetric or not. Thus, Ising-like phase transitions in a porous medium (the asymmetric case) are in a different universality class from the conventional random-field model (symmetric case).

  1. Lower Bounds for Phase Estimation of PSK Packets with Random Phase

    NASA Technical Reports Server (NTRS)

    Drake, Jeffrey

    1999-01-01

    In this paper, we derive new Cramer-Rao bounds (CRBs) for the estimation of phase from a block of random M-PSK (M=2,4,8) symbols where the phase to be estimated is a random variable. Existing bounds for 2 and 4-PSK which model the phase as non-random are extended to obtain a new 8-PSK CRB. The new random phase bounds are compared to the new 8-PSK and existing 2,4-PSK bounds which model the phase as non-random. We see that the random phase CRBs more accurately model the behavior if the phase, as normally happens, is suppose to be constrained to the interval [-pi/M,pi/M).

  2. Phase randomization of three-wave interactions in capillary waves.

    PubMed

    Punzmann, H; Shats, M G; Xia, H

    2009-08-01

    We present new experimental results on the transition from coherent-phase to random-phase three-wave interactions in capillary waves under parametric excitation. Above the excitation threshold, coherent wave harmonics spectrally broaden. An increase in the pumping amplitude increases spectral widths of wave harmonics and eventually causes a strong decrease in the degree of the three-wave phase coupling. The results point to the modulation instability of capillary waves, which leads to breaking of continuous waves into ensembles of short-lived wavelets or envelope solitons, as the reason for the phase randomization of three-wave interactions. PMID:19792572

  3. Continuity and Anomalous Fluctuations in Random Walks in Dynamic Random Environments: Numerics, Phase Diagrams and Conjectures

    NASA Astrophysics Data System (ADS)

    Avena, L.; Thomann, P.

    2012-07-01

    We perform simulations for one dimensional continuous-time random walks in two dynamic random environments with fast (independent spin-flips) and slow (simple symmetric exclusion) decay of space-time correlations, respectively. We focus on the asymptotic speeds and the scaling limits of such random walks. We observe different behaviors depending on the dynamics of the underlying random environment and the ratio between the jump rate of the random walk and the one of the environment. We compare our data with well known results for static random environment. We observe that the non-diffusive regime known so far only for the static case can occur in the dynamical setup too. Such anomalous fluctuations give rise to a new phase diagram. Further we discuss possible consequences for more general static and dynamic random environments.

  4. Effects of Blockiness on the phase behavior of random copolymers

    NASA Astrophysics Data System (ADS)

    Vanderwoude, Gordon; Shi, An-Chang

    Theoretical study of random block copolymers remains a challenging topic due in part to the sheer enormity of their phase space. In this study we use the self-consistent field theory to investigate the phase behaviour of linear (AB)n-type and (AB)n-C-type multiblock copolymers with randomly distributed A and B blocks. In particular, we examine the effect of ``blockiness'' of the random copolymers on the formation of ordered phases. The blockiness can be quantified by the average length of individual A or B blocks, which can be taken as a measure of the heterogeneity of the random copolymers. We observed that the critical value of the χ parameter, at which the order-disorder transition occurs, decreases with increasing blockiness in the (AB)n copolymers. We also observed that the phase behaviour of the (AB)n-C copolymers depends strongly on the blockiness of the random chain. In particular, the blockiness governs whether or not the A/B blocks can phase separate within the A/B domains, thus dictating whether the (AB)n-C behaves as A/B-C diblock copolymers or as ABC terpolymers. The theoretical phase diagrams will be compared with available experiments.

  5. Spatial Distribution of Phase Singularities in Optical Random Vector Waves.

    PubMed

    De Angelis, L; Alpeggiani, F; Di Falco, A; Kuipers, L

    2016-08-26

    Phase singularities are dislocations widely studied in optical fields as well as in other areas of physics. With experiment and theory we show that the vectorial nature of light affects the spatial distribution of phase singularities in random light fields. While in scalar random waves phase singularities exhibit spatial distributions reminiscent of particles in isotropic liquids, in vector fields their distribution for the different vector components becomes anisotropic due to the direct relation between propagation and field direction. By incorporating this relation in the theory for scalar fields by Berry and Dennis [Proc. R. Soc. A 456, 2059 (2000)], we quantitatively describe our experiments. PMID:27610854

  6. The Condensation Phase Transition in Random Graph Coloring

    NASA Astrophysics Data System (ADS)

    Bapst, Victor; Coja-Oghlan, Amin; Hetterich, Samuel; Raßmann, Felicia; Vilenchik, Dan

    2016-01-01

    Based on a non-rigorous formalism called the "cavity method", physicists have put forward intriguing predictions on phase transitions in diluted mean-field models, in which the geometry of interactions is induced by a sparse random graph or hypergraph. One example of such a model is the graph coloring problem on the Erdős-Renyi random graph G( n, d/ n), which can be viewed as the zero temperature case of the Potts antiferromagnet. The cavity method predicts that in addition to the k-colorability phase transition studied intensively in combinatorics, there exists a second phase transition called the condensation phase transition (Krzakala et al. in Proc Natl Acad Sci 104:10318-10323, 2007). In fact, there is a conjecture as to the precise location of this phase transition in terms of a certain distributional fixed point problem. In this paper we prove this conjecture for k exceeding a certain constant k 0.

  7. Ultrafast quantum random number generation based on quantum phase fluctuations.

    PubMed

    Xu, Feihu; Qi, Bing; Ma, Xiongfeng; Xu, He; Zheng, Haoxuan; Lo, Hoi-Kwong

    2012-05-21

    A quantum random number generator (QRNG) can generate true randomness by exploiting the fundamental indeterminism of quantum mechanics. Most approaches to QRNG employ single-photon detection technologies and are limited in speed. Here, we experimentally demonstrate an ultrafast QRNG at a rate over 6 Gbits/s based on the quantum phase fluctuations of a laser operating near threshold. Moreover, we consider a potential adversary who has partial knowledge on the raw data and discuss how one can rigorously remove such partial knowledge with postprocessing. We quantify the quantum randomness through min-entropy by modeling our system and employ two randomness extractors--Trevisan's extractor and Toeplitz-hashing--to distill the randomness, which is information-theoretically provable. The simplicity and high-speed of our experimental setup show the feasibility of a robust, low-cost, high-speed QRNG. PMID:22714224

  8. A phase 2, open-label, multicenter study of the long-term safety of siltuximab (an anti-interleukin-6 monoclonal antibody) in patients with multicentric Castleman disease

    PubMed Central

    van Rhee, Frits; Casper, Corey; Voorhees, Peter M.; Fayad, Luis E.; van de Velde, Helgi; Vermeulen, Jessica; Qin, Xiang; Qi, Ming; Tromp, Brenda; Kurzrock, Razelle

    2015-01-01

    Background Multicentric Castleman disease (MCD) is a rare, systemic lymphoproliferative disorder driven by interleukin (IL)-6 overproduction. Siltuximab, an anti-IL-6 monoclonal antibody, has demonstrated durable tumor and symptomatic responses in a multinational, randomized, placebo-controlled study of MCD. Methods This preplanned safety analysis was conducted to evaluate the long-term safety of siltuximab treatment among 19 patients with MCD who had stable disease or better and were enrolled in a phase-1 study and subsequent ongoing, open-label, phase-2 extension study. Dosing was 11 mg/kg administered intravenously every 3 weeks, per protocol, or every 6 weeks at the investigator's discretion. Safety monitoring focused on potential risks associated with the anti-IL-6 mechanism of action. Investigator-assessed disease control status was also documented. Results Median treatment duration for the 19 patients was 5.1 (range 3.4, 7.2) years, with 14 (74%) patients treated for >4 years. Grade-≥3 adverse events (AEs) reported in >1 patient included hypertension (n = 3) and nausea, cellulitis, and fatigue (n = 2 each). Grade-≥3 AEs at least possibly attributed to siltuximab were leukopenia, lymphopenia, and a serious AE of polycythemia (n = 1 each). Hypertriglyceridemia and hypercholesterolemia (total cholesterol) were reported in 8 and 9 patients, respectively. No disease relapses were observed, and 8 of 19 patients were able to switch to an every-6-week dosing schedule. Conclusions All MCD patients in this extension study have received siltuximab for a prolonged duration (up to 7 years) without evidence of cumulative toxicity or treatment discontinuations and with few serious infections. All patients are alive, demonstrate sustained disease control, and continue to receive siltuximab. PMID:26327301

  9. Random phase-free computer holography and its applications

    NASA Astrophysics Data System (ADS)

    Shimobaba, Tomoyoshi; Kakue, Takashi; Ito, Tomoyoshi

    2016-06-01

    Random phase is required in computer-generated hologram (CGH) to widely diffuse object light and to avoid its concentration on the CGH; however, the random phase causes considerable speckle noise in the reconstructed image and degrades the image quality. We introduce a simple and computationally inexpensive method that improves the image quality and reduces the speckle noise by multiplying the object light with the designed convergence light. We furthermore propose the improved method of the designed convergence light with iterative method to reduce ringing artifacts. Subsequently, as the application, a lensless zoomable holographic projection is introduced.

  10. A multicentre phase II study of vorinostat in patients with relapsed or refractory indolent B-cell non-Hodgkin lymphoma and mantle cell lymphoma

    PubMed Central

    Ogura, Michinori; Ando, Kiyoshi; Suzuki, Tatsuya; Ishizawa, Kenichi; Oh, Sung Yong; Itoh, Kuniaki; Yamamoto, Kazuhito; Au, Wing Yan; Tien, Hwei-Fang; Matsuno, Yoshihiro; Terauchi, Takashi; Yamamoto, Keiko; Mori, Masahiko; Tanaka, Yoshinobu; Shimamoto, Takashi; Tobinai, Kensei; Kim, Won Seog

    2014-01-01

    Although initial rituximab-containing chemotherapies achieve high response rates, indolent B-cell non-Hodgkin lymphoma (B-NHL), such as follicular lymphoma (FL), is still incurable. Therefore, new effective agents with novel mechanisms are anticipated. In this multicentre phase II study, patients with relapsed/refractory indolent B-NHL and mantle cell lymphoma (MCL) received vorinostat 200 mg twice daily for 14 consecutive days in a 21-d cycle until disease progression or unacceptable toxicity occurred. The primary endpoint was overall response rate (ORR) in FL patients and safety and tolerability in all patients. Secondary endpoints included progression-free survival (PFS). Fifty-six eligible patients were enrolled; 50 patients (39 with FL, seven with other B-NHL, and four with MCL) were evaluable for ORR, and 40 patients had received rituximab-containing prior chemotherapeutic regimens. For the 39 patients with FL, the ORR was 49% [95% confidence interval (CI): 32·4, 65·2] and the median PFS was 20 months (95% CI: 11·2, 29·7). Major toxicities were manageable grade 3/4 thrombocytopenia and neutropenia. Vorinostat offers sustained antitumour activity in patients with relapsed or refractory FL with an acceptable safety profile. Further investigation of vorinostat for clinical efficacy is warranted. PMID:24617454

  11. Absolute uniqueness of phase retrieval with random illumination

    NASA Astrophysics Data System (ADS)

    Fannjiang, Albert

    2012-07-01

    Random illumination is proposed to enforce absolute uniqueness and resolve all types of ambiguity, trivial or nontrivial, in phase retrieval. Almost sure irreducibility is proved for any complex-valued object whose support set has rank ⩾ 2. While the new irreducibility result can be viewed as a probabilistic version of the classical result by Bruck, Sodin and Hayes, it provides a novel perspective and an effective method for phase retrieval. In particular, almost sure uniqueness, up to a global phase, is proved for complex-valued objects under general two-point conditions. Under a tight sector constraint absolute uniqueness is proved to hold with probability exponentially close to unity as the object sparsity increases. Under a magnitude constraint with random amplitude illumination, uniqueness modulo global phase is proved to hold with probability exponentially close to unity as object sparsity increases. For general complex-valued objects without any constraint, almost sure uniqueness up to global phase is established with two sets of Fourier magnitude data under two independent illuminations. Numerical experiments suggest that random illumination essentially alleviates most, if not all, numerical problems commonly associated with the standard phasing algorithms.

  12. Phase conjugation with random fields and with deterministic and random scatterers

    SciTech Connect

    Gbur, G.; Wolf, E.

    1999-01-01

    The theory of distortion correction by phase conjugation, developed since the discovery of this phenomenon many years ago, applies to situations when the field that is conjugated is monochromatic and the medium with which it interacts is deterministic. In this Letter a generalization of the theory is presented that applies to phase conjugation of partially coherent waves interacting with either deterministic or random weakly scattering nonabsorbing media. {copyright} {ital 1999} {ital Optical Society of America}

  13. Transformation of phase transitions driven by an anisotropic random field

    NASA Astrophysics Data System (ADS)

    Popa-Nita, V.; Kralj, Samo

    2005-04-01

    We carry out a comparative study of the influence of a random anisotropy field on continuous and discontinuous phase transitions. The ordered phase, which is reached via a continuous symmetry breaking phase transition, is characterized by an order parameter and by a corresponding hydrodynamic continuum field. We assume that the response of the hydrodynamic field to the imposed disorder results in a domainlike pattern of the system. For a strong enough disorder both transitions become gradual. For weaker disorder strengths the disorder converts a second order transition into a discontinuous one.

  14. Neutron diffusion in a randomly inhomogeneous multiplying medium with random phase approximation

    SciTech Connect

    Imre, Kaya; Akcasu, A. Ziya

    2012-06-15

    Neutron diffusion in a randomly inhomogeneous multiplying medium is studied. By making use of a random phase assumption we show that the average neutron density approximately satisfies an integral equation in Fourier space, which is solved using Kummer functions. We used multi-dimensional formulation. In the case of one dimension, we obtain the result of Rosenbluth and Tao for the mean total density for large t. In the three-dimensional case, a closed form of solution is derived for the mean total neutron density. Its asymptotic behavior is also investigated for large t.

  15. Neutron diffusion in a randomly inhomogeneous multiplying medium with random phase approximation

    NASA Astrophysics Data System (ADS)

    Imre, Kaya; Akcasu, A. Ziya

    2012-06-01

    Neutron diffusion in a randomly inhomogeneous multiplying medium is studied. By making use of a random phase assumption we show that the average neutron density approximately satisfies an integral equation in Fourier space, which is solved using Kummer functions. We used multi-dimensional formulation. In the case of one dimension, we obtain the result of Rosenbluth and Tao for the mean total density for large t. In the three-dimensional case, a closed form of solution is derived for the mean total neutron density. Its asymptotic behavior is also investigated for large t.

  16. Three-dimensional photon counting double-random-phase encryption.

    PubMed

    Cho, Myungjin; Javidi, Bahram

    2013-09-01

    In this Letter, we present a three-dimensional (3D) photon counting double-random-phase encryption (DRPE) technique using passive integral imaging. A 3D photon counting DRPE can encrypt a 3D scene and provides more security and authentications due to photon counting Poisson nonlinear transformation on the encrypted image. In addition, 3D imaging allows verification of the 3D object at different depths. Preliminary results and performance evaluation have been presented. PMID:23988912

  17. Japanese POEMS syndrome with Thalidomide (J-POST) Trial: study protocol for a phase II/III multicentre, randomised, double-blind, placebo-controlled trial

    PubMed Central

    Katayama, Kanako; Misawa, Sonoko; Sato, Yasunori; Sobue, Gen; Yabe, Ichiro; Watanabe, Osamu; Nishizawa, Masatoyo; Kusunoki, Susumu; Kikuchi, Seiji; Nakashima, Ichiro; Ikeda, Shu-ichi; Kohara, Nobuo; Kanda, Takashi; Kira, Jun-ichi; Hanaoka, Hideki; Kuwabara, Satoshi

    2015-01-01

    Introduction Polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome is a fatal systemic disorder associated with plasma cell dyscrasia and the overproduction of the vascular endothelial growth factor (VEGF). Recently, the prognosis of POEMS was substantially improved by introduction of therapeutic intervention for myeloma. However, no randomised clinical trial has been performed because of the rarity and severity of the disease. Methods and analysis The Japanese POEMS syndrome with Thalidomide (J-POST) Trial is a phase II/III multicentre, double-blinded, randomised, controlled trial that aims to evaluate the efficacy and safety of a 24-week treatment with thalidomide in POEMS syndrome, with an additional 48-week open-label safety study. Adults with POEMS syndrome who have no indication for transplantation are assessed for eligibility at 12 tertiary neurology centres in Japan. Patients who satisfy the eligibility criteria are randomised (1:1) to receive thalidomide (100–300 mg daily) plus dexamethasone (12 mg/m2 on days 1–4 of a 28-day cycle) or placebo plus dexamethasone. Both treatments were administered for 24 weeks (six cycles; randomised comparative study period). Patients who complete the randomised study period or show subacute deterioration during the randomised period participate in the subsequent 48-week open-label safety study (long-term safety period). The primary end point of the study is the reduction rate of serum VEGF levels at 24 weeks. Ethics and dissemination The protocol was approved by the Institutional Review Board of each hospital. The trial was notified and registered at the Pharmaceutical and Medical Devices Agency, Japan (No. 22-1716). The J-POST Trial is currently ongoing and is due to finish in August 2015. The findings of this trial will be disseminated through peer-reviewed publications and conference presentations and will also be disseminated to participants. Trial registration number

  18. Efficacy of Rivaroxaban for thromboprophylaxis after Knee Arthroscopy (ERIKA). A phase II, multicentre, double-blind, placebo-controlled randomised study.

    PubMed

    Camporese, Giuseppe; Bernardi, Enrico; Noventa, Franco; Bosco, Mario; Monteleone, Giuseppe; Santoro, Luca; Bortoluzzi, Cristiano; Freguja, Stefano; Nardin, Michela; Marullo, Matteo; Zanon, Giacomo; Mazzola, Claudio; Damiani, Guido; Maniscalco, Pietro; Imberti, Davide; Lodigiani, Corrado; Becattini, Cecilia; Tonello, Chiara; Agnelli, Giancarlo

    2016-08-01

    Without thromboprophylaxis, knee arthroscopy (KA) carries a low to moderate risk of venous thromboembolism. Over 5 million arthroscopies are performed worldwide yearly. It was our study objective to assess the efficacy and safety of rivaroxaban for thromboprophylaxis after therapeutic KA. Patients undergoing KA in nine Italian teaching or community hospitals were allocated to once-daily rivaroxaban (10 mg) or placebo for seven days in a phase II, multicentre, double-blind, placebo-controlled randomised trial. The primary efficacy outcome was a composite of all-cause death, symptomatic thromboembolism and asymptomatic proximal DVT at three months; major bleeding represented the primary safety outcome. All patients underwent whole-leg ultrasonography at day 7(+1), or earlier if symptomatic. A total of 241 patients were randomised (122 rivaroxaban, 119 placebo), and 234 completed the study. The primary efficacy outcome occurred in 1/120 of the rivaroxaban group and in 7/114 of the placebo group (0.8 % vs 6.1 %, respectively, p=0.03; absolute risk difference, -5.3 %, 95 % CI, -11.4 to -0.8; crude relative risk 0.14, 95 % CI, 0.02 to 0.83; number-needed-to-treat=19). No major bleedings were observed. We found no association between different arthroscopic procedures and thrombotic events. Small sample size, high exclusion rate, and low number of anterior cruciate ligament reconstruction procedures are the main limitations of our study. In conclusion, a seven-day course of 10-mg rivaroxaban may be safely employed for thromboprophylaxis after KA. Whether prophylaxis after KA should be given to all patients, or to selected "high-risk" subjects, remains to be determined. A larger trial to verify our preliminary results is warranted. PMID:27075710

  19. Antiproliferative effects of lanreotide autogel in patients with progressive, well-differentiated neuroendocrine tumours: a Spanish, multicentre, open-label, single arm phase II study

    PubMed Central

    2013-01-01

    Background Somatostatin analogues (SSAs) are indicated to relieve carcinoid syndrome but seem to have antiproliferative effects on neuroendocrine tumours (NETs). This is the first prospective study investigating tumour stabilisation with the long-acting SSA lanreotide Autogel in patients with progressive NETs. Methods This was a multicentre, open-label, phase II trial conducted in 17 Spanish specialist centres. Patients with well-differentiated NETs and radiologically confirmed progression within the previous 6 months received lanreotide Autogel, 120 mg every 28 days over ≤92 weeks. The primary endpoint was progression-free survival (PFS). Secondary endpoints were response rate, tumour biomarkers, symptom control, quality of life (QoL), and safety. Radiographic imaging was assessed by a blinded central radiologist. Results Of 30 patients included in the efficacy and safety analyses, 40% had midgut tumours and 27% pancreatic tumours; 63% of tumours were functioning. Median PFS time was 12.9 (95% CI: 7.9, 16.5) months, and most patients achieved disease stabilisation (89%) or partial response (4%). No deterioration in QoL was observed. Nineteen patients (63%) experienced treatment-related adverse events, most frequently diarrhoea and asthenia; only one treatment-related adverse event (aerophagia) was severe. Conclusion Lanreotide Autogel provided effective tumour stabilisation and PFS >12 months in patients with progressive NETs ineligible for surgery or chemotherapy, with a safety profile consistent with the pharmacology of the class. Trial registration ClinicalTrials.gov Identifier NCT00326469; EU Clinical Trial Register EudraCT no 2004-002871-18. PMID:24053191

  20. A phase II, single-arm, multicentre study of coltuximab ravtansine (SAR3419) and rituximab in patients with relapsed or refractory diffuse large B-cell lymphoma.

    PubMed

    Coiffier, Bertrand; Thieblemont, Catherine; de Guibert, Sophie; Dupuis, Jehan; Ribrag, Vincent; Bouabdallah, Réda; Morschhauser, Franck; Navarro, Robert; Le Gouill, Steven; Haioun, Corinne; Houot, Roch; Casasnovas, Olivier; Holte, Harald; Lamy, Thierry; Broussais, Florence; Payrard, Sandrine; Hatteville, Laurence; Tilly, Hervé

    2016-06-01

    In this phase II, multicentre, single-arm study, 52 patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) received the anti-CD19 antibody-drug conjugate coltuximab ravtansine (55 mg/m(2) ) and rituximab (375 mg/m(2) ) weekly for 4 weeks, then every 2 weeks for 8 weeks. The primary endpoint was objective response rate (ORR) by International Working Group Criteria. The primary objective was to reject the null hypothesis of an ORR of ≤40%. Among 45 evaluable patients, the ORR was 31·1% (80% confidence interval [CI]: 22·0-41·6%) and the primary objective was not met. The ORR appeared higher in patients with relapsed disease (58·3% [80% CI: 36·2-78·1%]) versus those refractory to their last (42·9% [80% CI: 17·0-72·1%]) or first-line therapy (15·4% [80% CI: 6·9-28·4%]). Median progression-free survival, overall survival and duration of response were 3·9 [80% CI: 3·22-3·98], 9·0 [80% CI: 6·47-13·67] and 8·6 (range: 0-18) months, respectively. The pharmacokinetics of both drugs were unaffected by co-administration. Common adverse events included gastrointestinal disorders (52%) and asthenia (25%). No patients discontinued due to adverse events. In conclusion, coltuximab ravtansine with rituximab was well tolerated and yielded clinical responses in a subset of patients with relapsed/refractory DLBCL. PMID:27010483

  1. A multi-centre phase IIa clinical study of predictive testing for preeclampsia: improved pregnancy outcomes via early detection (IMPROvED)

    PubMed Central

    2013-01-01

    Background 5% of first time pregnancies are complicated by pre-eclampsia, the leading cause of maternal death in Europe. No clinically useful screening test exists; consequentially clinicians are unable to offer targeted surveillance or preventative strategies. IMPROvED Consortium members have pioneered a personalised medicine approach to identifying blood-borne biomarkers through recent technological advancements, involving mapping of the blood metabolome and proteome. The key objective is to develop a sensitive, specific, high-throughput and economically viable early pregnancy screening test for pre-eclampsia. Methods/Design We report the design of a multicentre, phase IIa clinical study aiming to recruit 5000 low risk primiparous women to assess and refine innovative prototype tests based on emerging metabolomic and proteomic technologies. Participation involves maternal phlebotomy at 15 and 20 weeks’ gestation, with optional testing and biobanking at 11 and 34 weeks. Blood samples will be analysed using two innovative, proprietary prototype platforms; one metabolomic based and one proteomic based, both of which outperform current biomarker based screening tests at comparable gestations. Analytical and clinical data will be collated and analysed via the Copenhagen Trials Unit. Discussion The IMPROvED study is expected to refine proteomic and metabolomic panels, combined with clinical parameters, and evaluate clinical applicability as an early pregnancy predictive test for pre-eclampsia. If ‘at risk’ patients can be identified, this will allow stratified care with personalised fetal and maternal surveillance, early diagnosis, timely intervention, and significant health economic savings. The IMPROvED biobank will be accessible to the European scientific community for high quality research into the cause and prevention of adverse pregnancy outcome. Trial registration Trial registration number NCT01891240 The IMPROvED project is funded by the seventh framework

  2. Pre-Study protocol MagPEP: a multicentre randomized controlled trial of magnesium sulphate in the prevention of post-ERCP pancreatitis

    PubMed Central

    2013-01-01

    Background Acute pancreatitis is the most common complication of diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP). In spite of continuing research, no pharmacologic agent capable of effectively reducing the incidence of ERCP-induced pancreatitis has found its way into clinical practise. A number of experimental studies suggest that intrapancreatic calcium concentrations play an important role in the initiation of intracellular protease activation, an initiating step in the course of acute pancreatitis. Magnesium can act as a calcium-antagonist and counteracts effects in calcium signalling. It can thereby attenuate the intracellular activation of proteolytic digestive enzymes in the pancreas and reduces the severity of experimental pancreatitis when administered either intravenously or as a food supplement. Methods We designed a randomized, double-blind, placebo-controlled phase III study to test whether the administration of intravenous magnesium sulphate before and after ERCP reduces the incidence and the severity of post-ERCP pancreatitis. A total of 502 adult patients with a medical indication for ERCP are to be randomized to receive either 4930 mg magnesium sulphate (= 20 mmol magnesium) or placebo 60 min before and 6 hours after ERCP. The incidence of clinical post-ERCP pancreatitis, hyperlipasemia, pain levels, use of analgetics and length of hospital stay will be evaluated. Conclusions If magnesium sulphate is found to be effective in preventing post-ERCP pancreatitis, this inexpensive agent with limited adverse effects could be used as a routine pharmacological prophylaxis. Trial registration Current Controlled Trials ISRCTN46556454 PMID:23320650

  3. Drugs, Women and Violence in the Americas: U.S. Results of a Multi-Centric Pilot Project (Phase 1).

    PubMed

    González-Guarda, Rosa María; Peragallo, Nilda; Lynch, Ami; Nemes, Susanna

    2010-09-01

    OBJECTIVES: To explore the collective and individual experiences that Latin American females in the U. S. have with substance abuse, violence and risky sexual behaviors. METHODS: This study was conducted in two phases that were carried out from July 2006 to June 2007 in south Florida. This paper covers Phase 1. In Phase 1, focus groups were conducted among 93 women in English, Spanish and Portuguese. Through content analyses of the focus group transcriptions, major themes were identified. RESULTS: Participants identified substance abuse, violence and risky sexual behaviors as closely related problems of great concern in Latina women in the U.S. Three important themes emerged from the focus groups. These included "Living in the US and the Devaluing of Latino Culture," the "Vicious Cycle of Abuse" and "Breaking the Silence". CONCLUSIONS: The results from this study suggest that substance abuse, violence and HIV should be addressed in an integrative and comprehensive manner. Recommendations for the development of policies, programs and services addressing substance abuse, violence and risk for HIV among Latinos are provided. PMID:21593995

  4. Random and ordered phases of off-lattice rhombus tiles.

    PubMed

    Whitelam, Stephen; Tamblyn, Isaac; Beton, Peter H; Garrahan, Juan P

    2012-01-20

    We study the covering of the plane by nonoverlapping rhombus tiles, a problem well studied only in the limiting case of dimer coverings of regular lattices. We go beyond this limit by allowing tiles to take any position and orientation on the plane, to be of irregular shape, and to possess different types of attractive interactions. Using extensive numerical simulations, we show that at large tile densities there is a phase transition from a fluid of rhombus tiles to a solid packing with broken rotational symmetry. We observe self-assembly of broken-symmetry phases, even at low densities, in the presence of attractive tile-tile interactions. Depending on the tile shape and interactions, the solid phase can be random, possessing critical orientational fluctuations, or crystalline. Our results suggest strategies for controlling tiling order in experiments involving "molecular rhombi." PMID:22400760

  5. Random and ordered phases of off-lattice rhombus tiles

    NASA Astrophysics Data System (ADS)

    Whitelam, Stephen; Tamblyn, Isaac; Beton, Peter; Garrahan, Juan

    2012-02-01

    We study the covering of the plane by non-overlapping rhombus tiles, a problem well-studied only in the limiting case of dimer coverings of regular lattices. We go beyond this limit by allowing tiles to take any position and orientation on the plane, to be of irregular shape, and to possess different types of attractive interactions. Using extensive numerical simulations we show that at large tile densities there is a phase transition from a fluid of rhombus tiles to a solid packing with broken rotational symmetry. We observe self-assembly of broken-symmetry phases, even at low densities, in the presence of attractive tile-tile interactions. Depending on tile shape and interactions the solid phase can be random, possessing critical orientational fluctuations, or crystalline. Our results suggest strategies for controlling tiling order in experiments involving ``molecular rhombi.''

  6. Random and Ordered Phases of Off-Lattice Rhombus Tiles

    NASA Astrophysics Data System (ADS)

    Whitelam, Stephen; Tamblyn, Isaac; Beton, Peter H.; Garrahan, Juan P.

    2012-01-01

    We study the covering of the plane by nonoverlapping rhombus tiles, a problem well studied only in the limiting case of dimer coverings of regular lattices. We go beyond this limit by allowing tiles to take any position and orientation on the plane, to be of irregular shape, and to possess different types of attractive interactions. Using extensive numerical simulations, we show that at large tile densities there is a phase transition from a fluid of rhombus tiles to a solid packing with broken rotational symmetry. We observe self-assembly of broken-symmetry phases, even at low densities, in the presence of attractive tile-tile interactions. Depending on the tile shape and interactions, the solid phase can be random, possessing critical orientational fluctuations, or crystalline. Our results suggest strategies for controlling tiling order in experiments involving “molecular rhombi.”

  7. Phase diffusion and random walk interpretation of electromagnetic scattering

    NASA Astrophysics Data System (ADS)

    Bahcivan, Hasan; Hysell, David L.; Kelley, Michael C.

    2003-08-01

    The relaxation behavior of phase observables for different particle diffusion models is found to establish a ground for radioscience interpretations of coherent backscatter spectra. The characteristic function for a random walk process at twice the incident radiation wave number is associated with the complex amplitude of the scattered field from a medium containing refractive index fluctuations. The phase relaxation function can be connected to the evolution of the characteristic function and may describe the average regression of the scattered field from a spontaneous fluctuation undergoing turbulent mixing. This connection holds when we assume that the stochastic description of particle movements based on a diffusion model is valid. The phase relaxation function, when identified as the generalized susceptibility function of the fluctuation dissipation theorem, is related to the spectral density of the scattered field from steady-state fluctuations.

  8. Treatment of unresectable stage IV metastatic melanoma with aviscumine after anti-neoplastic treatment failure: a phase II, multi-centre study

    PubMed Central

    2014-01-01

    Background Aviscumine, a recombinant plant protein, is an immune modulator that induces ribotoxic stress at the 28S ribosomal RNA subunit. In this way cytokine release and T-cell responses are enhanced. This phase II trial was conducted to test the efficacy and safety of aviscumine in patients with systemically pre-treated metastatic melanoma stage IV. Methods A total of 32 patients with progressive stage IV melanoma after failure of standard therapy were enrolled onto a single-arm, multi-centre, open-label, phase II trial. All patients had an ECOG performance status of 0 or 1. Patients received 350 ng aviscumine twice weekly by subcutaneous injection until progression. The primary end points were progression-free survival (PFS) and overall survival (OS). Safety was assessed as adverse events (AEs). Tumor response was assessed every eight weeks and survival of patients was followed up to one year after the end of therapy. Thirty one patients (intent-to-treat population (ITT)) were assessed for efficacy; safety was assessed in the whole population. Results One patient achieved a partial response (PR) and 10 patients showed stable disease/no change (SD). The median progression-free survival (mPFS) was 63 days (95% CI 57–85) and median overall survival (mOS) was 335 days (95% CI 210–604). In total 210 treatment-emergent adverse events were recorded. Grade 1 or 2 AEs occurred in 72% of patients and were mostly application-site effects such as pruritus Grade 3–4 treatment-emergent drug-related adverse events occurred in 9% of patients. Conclusion These results suggest that aviscumine may have a clinical impact in patients with previously treated metastatic melanoma and provide rationale for further clinical evaluation of this agent. In the light of effective new immune checkpoint blockers it might be a candidate for combinations with these agents. Trial registration ClinicalTrials.gov: NCT00658437 PMID:25324973

  9. Masitinib in the treatment of active rheumatoid arthritis: results of a multicentre, open-label, dose-ranging, phase 2a study

    PubMed Central

    Tebib, Jacques; Mariette, Xavier; Bourgeois, Pierre; Flipo, René-Marc; Gaudin, Philippe; Le Loët, Xavier; Gineste, Paul; Guy, Laurent; Mansfield, Colin D; Moussy, Alain; Dubreuil, Patrice; Hermine, Olivier; Sibilia, Jean

    2009-01-01

    Introduction Since current treatment options for patients suffering from active rheumatoid arthritis (RA) remain inadequate, especially for those unresponsive to disease-modifying antirheumatic drugs (DMARDs), new and improved medication is needed. This study evaluates the safety and efficacy of masitinib (AB1010), a potent and selective protein tyrosine kinase inhibitor of c-KIT, in the monotherapy treatment of DMARD-refractory RA. Methods This was a multicentre, uncontrolled, open-label, randomised, dose-ranging, phase 2a trial. Masitinib was administered orally to 43 patients who had inadequate response to DMARDs, at initial randomised dosing levels of 3 and 6 mg/kg per day over a 12-week period. Dose adjustment was permitted based upon tolerability and response criteria. Efficacy was assessed via American College of Rheumatology 20%/50%/70% improvement criteria (ACR20/50/70) responses, disease activity score using 28 joint counts (DAS28), index of improvement in RA (ACRn) and C-reactive protein (CRP) improvement, relative to baseline at week 12. Results Improvement was observed in all efficacy endpoints, including ACR20/50/70 scores of 54%, 26% and 8%, respectively, and a reduction in CRP level by greater than 50% for approximately half the population. This improvement was sustainable throughout an extension phase (> 84 weeks) and was also independent of initial DMARD resistance (anti-tumour necrosis factor-alpha and/or methotrexate). A relatively high patient withdrawal rate (37%) required the use of last observation carried forward (LOCF) data imputation. Incidence of adverse events was high (95%), although the majority were of mild or moderate severity with a considerable decline in frequency observed after 12 weeks of treatment. Two nonfatal serious adverse events were reported. Dose-response analyses tentatively indicate that an initial dosing level of 6.0 mg/kg per day administered orally in two daily intakes is the most appropriate, based upon potency

  10. Wavefront watermarking of technical and biological samples using digital random phase modulation and phase retrieval

    NASA Astrophysics Data System (ADS)

    Carpio, Justine Patricia L.; Almoro, Percival F.

    2014-10-01

    A technique for digital watermarking of smooth object wavefronts using digital random phase modulation and multiple-plane iterative phase retrieval is demonstrated experimentally. A complex-valued watermark is first encrypted using two random phase masks of known distributions before being superposed onto a set of host wavefront intensity patterns. Encryption scaling factor and depth of randomization of the masks are optimized such that the amplitude and phase watermarks are decrypted successfully and are not distorting the host wavefront. Given that the watermarked intensity patterns and the numerous decryption keys are available (i.e. distances between recording planes, light source wavelength, pixel size, random phase masks and their distances to the planes are all known), increasing the number of watermarked patterns used results in enhanced quality of decrypted watermarks. The main advantage of wavefront watermarking via the phase retrieval approach compared to the holographic approach is the avoidance of reference wave-induced aberration. Watermarking of wavefronts from lenses and unstained human cheek cells demonstrate the effectiveness of the technique.

  11. Laser-beam apodization with a graded random phase window.

    PubMed

    Haas, R A; Summers, M A; Linford, G J

    1986-10-01

    Experiments and analysis indicate that graded random phase modulation can be used to apodize a laser beam. In the case of an obscuration or a hard edge it can prevent the formation of Fresnel-diffraction ripples. For example, here the interaction of a 1-microm-wavelength laser beam with a central obscuration of half-width a = 100 microm is studied theoretically. It is found that if the exit surface of a window, placed immediately downstream of the obstacle, is randomly modulated with a Gaussian amplitude transverse correlation length l = 50 microm and a mean-square amplitude that decreases exponentially from a peak height of ~1 microm(2) away from the center of the obscuration with transverse scale length L = 500 microm, then the Fresnel-diffraction ripples normally produced by the obscuration are eliminated. The scaling of these results is also discussed. The calculations are in general agreement with experimental results. PMID:19738707

  12. Doorway states in the random-phase approximation

    SciTech Connect

    De Pace, A.; Molinari, A.; Weidenmüller, H.A.

    2014-12-15

    By coupling a doorway state to a sea of random background states, we develop the theory of doorway states in the framework of the random-phase approximation (RPA). Because of the symmetry of the RPA equations, that theory is radically different from the standard description of doorway states in the shell model. We derive the Pastur equation in the limit of large matrix dimension and show that the results agree with those of matrix diagonalization in large spaces. The complexity of the Pastur equation does not allow for an analytical approach that would approximately describe the doorway state. Our numerical results display unexpected features: The coupling of the doorway state with states of opposite energy leads to strong mutual attraction.

  13. Safety and efficacy of oral febuxostat for treatment of HLA-B*5801-negative gout: a randomized, open-label, multicentre, allopurinol-controlled study

    PubMed Central

    Yu, K-H; Lai, J-H; Hsu, P-N; Chen, D-Y; Chen, C-J; Lin, H-Y

    2016-01-01

    Objectives: This phase IIIB study compared the efficacy and safety of febuxostat and allopurinol in gout patients with or without tophi who were HLA-B*5801 negative. Method: Eligible patients were randomized to a febuxostat group (80 mg QD) or an allopurinol group (300 mg QD). Following an initial 2-week washout period, over the next 12 weeks we made five measurements of serum urate levels along with assessments of adverse events (AEs). Results: Forty-three out of 152 screened subjects (28.3%) were ineligible either because of the presence of the HLA-B*5801 allele or for various other reasons. The febuxostat group (n = 54) and the allopurinol group (n = 55) had no significant differences in demographic or baseline characteristics. From week 2 to week 12, the febuxostat group had a significantly lower serum urate level than the allopurinol group (p ≤ 0.001 for all comparisons) and significantly more patients with serum urate levels less than 6.0 mg/dL. The serum urate levels of the febuxostat group declined by more than 40% from week 2 to week 12 and this decrease was greater than that in the allopurinol group (~30%). The two groups were similar in terms of AEs. Conclusions: Febuxostat was more effective than allopurinol in reducing the serum urate levels of Han Chinese patients with gout or tophaceous gout who were HLA-B*5801 negative, without causing any serious skin reactions. Febuxostat should be considered for treatment of Han Chinese patients with gout who are HLA-B*5801 negative. PMID:26771445

  14. Finite amplitude method for the quasiparticle random-phase approximation

    SciTech Connect

    Avogadro, Paolo; Nakatsukasa, Takashi

    2011-07-15

    We present the finite amplitude method (FAM), originally proposed in Ref. [17], for superfluid systems. A Hartree-Fock-Bogoliubov code may be transformed into a code of the quasiparticle-random-phase approximation (QRPA) with simple modifications. This technique has advantages over the conventional QRPA calculations, such as coding feasibility and computational cost. We perform the fully self-consistent linear-response calculation for the spherical neutron-rich nucleus {sup 174}Sn, modifying the hfbrad code, to demonstrate the accuracy, feasibility, and usefulness of the FAM.

  15. Modified random phase approximation for multipole excitations at finite temperature

    SciTech Connect

    Dang, N.D. )

    1992-03-01

    The modified finite-temperature random phase approximation (FT-RPA) has been constructed by taking the influence of thermostat on the structure of quasiparticles into account. The modified FT-RPA linear response for electric quadrupole ({lambda}{sup {pi}}=2{sup +}) and octupole ({lambda}{sup {pi}}=3{sup {minus}}) excitations in {sup 58}Ni has been calculated as a function of the nuclear temperature. As compared to the conventional FT-RPA, the modified FT-RPA has given a stronger spreading for the strength distribution of quadrupole excitations at finite temperature {ital T}{le}3 MeV.

  16. Effect of adding mFOLFOX6 after neoadjuvant chemoradiation in locally advanced rectal cancer: a multicentre, phase 2 trial

    PubMed Central

    Garcia-Aguilar, Julio; Chow, Oliver S; Smith, David D; Marcet, Jorge E; Cataldo, Peter A; Varma, Madhulika G; Kumar, Anjali S; Oommen, Samuel; Coutsoftides, Theodore; Hunt, Steven R; Stamos, Michael J; Ternent, Charles A; Herzig, Daniel O; Fichera, Alessandro; Polite, Blase N; Dietz, David W; Patil, Sujata; Avila, Karin

    2015-01-01

    Summary Background Patients with locally advanced rectal cancer who achieve a pathological complete response to neoadjuvant chemoradiation have an improved prognosis. The need for surgery in these patients has been questioned, but the proportion of patients achieving a pathological complete response is small. We aimed to assess whether adding cycles of mFOLFOX6 between chemoradiation and surgery increased the proportion of patients achieving a pathological complete response. Methods We did a phase 2, non-randomised trial consisting of four sequential study groups of patients with stage II–III locally advanced rectal cancer at 17 institutions in the USA and Canada. All patients received chemoradiation (fluorouracil 225 mg/m2 per day by continuous infusion throughout radiotherapy, and 45.0 Gy in 25 fractions, 5 days per week for 5 weeks, followed by a minimum boost of 5.4 Gy). Patients in group 1 had total mesorectal excision 6–8 weeks after chemoradiation. Patients in groups 2–4 received two, four, or six cycles of mFOLFOX6, respectively, between chemoradiation and total mesorectal excision. Each cycle of mFOLFOX6 consisted of racemic leucovorin 200 mg/m2 or 400 mg/m2, according to the discretion of the treating investigator, oxaliplatin 85 mg/m2 in a 2-h infusion, bolus fluorouracil 400 mg/m2 on day 1, and a 46-h infusion of fluorouracil 2400 mg/m2. The primary endpoint was the proportion of patients who achieved a pathological complete response, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00335816. Findings Between March 24, 2004, and Nov 16, 2012, 292 patients were registered, 259 of whom (60 in group 1, 67 in group 2, 67 in group 3, and 65 in group 4) met criteria for analysis. 11 (18%, 95% CI 10–30) of 60 patients in group 1, 17 (25%, 16–37) of 67 in group 2, 20 (30%, 19–42) of 67 in group 3, and 25 (38%, 27–51) of 65 in group 4 achieved a pathological complete response (p=0.0036). Study group was

  17. A randomised phase II multicentre trial of irinotecan (CPT-11) using four different schedules in patients with metastatic colorectal cancer.

    PubMed

    Schoemaker, N E; Kuppens, I E L M; Moiseyenko, V; Glimelius, B; Kjaer, M; Starkhammer, H; Richel, D J; Smaaland, R; Bertelsen, K; Poulsen, J P; Voznyi, E; Norum, J; Fennelly, D; Tveit, K M; Garin, A; Gruia, G; Mourier, A; Sibaud, D; Lefebvre, P; Beijnen, J H; Schellens, J H M; ten Bokkel Huinink, W W

    2004-10-18

    The purpose of this phase II trial was to compare the efficacy, safety and pharmacokinetics of four irinotecan schedules for the treatment of metastatic colorectal cancer. In total, 174 5-fluorouracil pretreated patients were randomised to: arm A (n=41), 350 mg m(-2) irinotecan as a 90-min i.v. infusion q3 weeks; arm B (n=38), 125 mg m(-2) irinotecan as a 90-min i.v. infusion weekly x 4 weeks q6 weeks; arm C (n=46), 250 mg m(-2) irinotecan as a 90-min i.v. infusion q2 weeks; or arm D (n=49), 10 mg m(-2) day(-1) irinotecan as a 14-day continuous infusion q3 weeks. No significant differences in efficacy across the four arms were observed, although a shorter time to treatment failure was noted for arm D (1.7 months; P=0.02). Overall response rates were in the range 5-11%. Secondary end points included median survival (6.4-9.4 months), and time to progression (2.7-3.8 months) and treatment failure (1.7-3.2 months). Similarly, there were no significant differences in the incidence of grade 3-4 toxicities, although the toxicity profile between arms A, B, and C and D did differ. Generally, significantly less haematologic toxicity, alopecia and cholinergic syndrome were observed in arm D; however, there was a trend for increased gastrointestinal toxicity. Irinotecan is an effective and safe second-line treatment for colorectal cancer. The schedules examined yielded equivalent results, indicating that there is no advantage of the prolonged vs short infusion schedules. PMID:15381932

  18. Pazopanib and depot octreotide in advanced, well-differentiated neuroendocrine tumours: a multicentre, single-group, phase 2 study

    PubMed Central

    Phan, Alexandria T; Halperin, Daniel M; Chan, Jennifer A; Fogelman, David R; Hess, Kenneth R; Malinowski, Paige; Regan, Eileen; Ng, Chaan S; Yao, James C; Kulke, Matthew H

    2015-01-01

    Summary Background Treatment options for advanced, well-differentiated neuroendocrine tumours (NETs) remain scarce. Pazopanib is an orally bioavailable, small molecule, multitargeted kinase inhibitor that inhibits VEGF receptors 1, 2, and 3. We did a study of the efficacy of pazopanib with depot octreotide in patients with advanced NETs. Methods We did a parallel cohort study of patients with metastatic or locally advanced grade 1–2 carcinoid tumours or pancreatic NETs, by use of a single-group, two-stage design. Patients received pazopanib 800 mg orally once per day and octreotide at their preprotocol dosage. The primary endpoint was the proportion of patients achieving an objective response, as assessed by investigators, by intention-to-treat analysis. This study is registered with ClinicalTrials.gov, identifier NCT00454363, and was completed in March, 2014. Findings Between April 12, 2007, and July 2, 2009, we enrolled 52 patients, including 32 individuals with pancreatic NETs and 20 individuals with carcinoid tumours. Seven (21.9%, 95% CI 11.0–38.8) of 32 patients with pancreatic NETs achieved an objective response. We detected no responses in the first stage of the cohort with carcinoid tumours, and we terminated accrual at 20 patients. Toxic effects included one patient with grade 4 hypertriglyceridaemia and one with grade 4 thrombosis, with the most common grade three events being aminotransferase increases and neutropenia, each of which happened in 3 patients. In all 52 patients, the most frequently observed toxic effects were fatigue (39 [75%]), nausea (33 [63%]), diarrhoea (33 [63%]), and hypertension (28 [54%]). Interpretation Treatment with pazopanib is associated with tumour response for patients with pancreatic NETs, but not for carcinoid tumours; a randomised controlled phase 3 study to assess pazopanib in advanced pancreatic NETs is warranted. Funding US National Cancer Institute of the National Institutes of Health. PMID:25956795

  19. The peculiar phase structure of random graph bisection

    SciTech Connect

    Percus, Allon G; Istrate, Gabriel; Goncalves, Bruno T; Sumi, Robert Z

    2008-01-01

    The mincut graph bisection problem involves partitioning the n vertices of a graph into disjoint subsets, each containing exactly n/2 vertices, while minimizing the number of 'cut' edges with an endpoint in each subset. When considered over sparse random graphs, the phase structure of the graph bisection problem displays certain familiar properties, but also some surprises. It is known that when the mean degree is below the critical value of 2 log 2, the cutsize is zero with high probability. We study how the minimum cutsize increases with mean degree above this critical threshold, finding a new analytical upper bound that improves considerably upon previous bounds. Combined with recent results on expander graphs, our bound suggests the unusual scenario that random graph bisection is replica symmetric up to and beyond the critical threshold, with a replica symmetry breaking transition possibly taking place above the threshold. An intriguing algorithmic consequence is that although the problem is NP-hard, we can find near-optimal cutsizes (whose ratio to the optimal value approaches 1 asymptotically) in polynomial time for typical instances near the phase transition.

  20. A new phase of disordered phonons modelled by random matrices

    NASA Astrophysics Data System (ADS)

    Schmittner, Sebastian; Zirnbauer, Martin

    2015-03-01

    Starting from the clean harmonic crystal and not invoking two-level systems, we propose a model for phonons in a disordered solid. In this model the strength of mass and spring constant disorder can be increased separately. Both types of disorder are modelled by random matrices that couple the degrees of freedom locally. Treated in coherent potential approximation (CPA), the speed of sound decreases with increasing disorder until it reaches zero at finite disorder strength. There, a critical transition to a strong disorder phase occurs. In this novel phase, we find the density of states at zero energy in three dimensions to be finite, leading to a linear temperature dependence of the heat capacity, as observed experimentally for vitreous systems. For any disorder strength, our model is stable, i.e. masses and spring constants are positive, and there are no runaway dynamics. This is ensured by using appropriate probability distributions, inspired by Wishart ensembles, for the random matrices. The CPA self-consistency equations are derived in a very accessible way using planar diagrams. The talk focuses on the model and the results. The first author acknowledges financial support by the Deutsche Telekom Stiftung.

  1. Anti-pruritic Effect of Sertaconazole 2% Cream in Atopic Dermatitis Subjects: A Prospective, Randomized, Double-blind, Vehicle-controlled, Multi-centre Clinical Trial of Efficacy, Safety and Local Tolerability.

    PubMed

    Ständer, Sonja; Metz, Martin; Ramos F, Mac H; Maurer, Marcus; Schoepke, Nicole; Tsianakas, Athanasios; Zeidler, Claudia; Luger, Thomas A

    2016-08-23

    This study was a prospective, parallel-group, randomized, double-blind, vehicle-controlled, multi-centre clinical trial to compare the efficacy of topical sertaconazole 2% cream with vehicle in reducing chronic pruritus in subjects with atopic dermatitis, and to assess its safety and local tolerability. A total of 70 subjects applied either of the 2 treatments twice daily for a period of 4 weeks on affected, itchy skin areas. Treatment efficacy was evaluated primarily considering the item itch intensity on a 5-point verbal rating scale. Insomnia, state of atopic dermatitis (Scoring Atopic Dermatitis; SCORAD), quality of life and therapy benefit were also assessed. No significant difference between active treatment and vehicle was found at any of the time-points for any of the investigated parameters. Under the experimental conditions of the study, sertaconazole 2% cream did not exert anti-pruritic effects that were better than vehicle in subjects with atopic dermatitis who had chronic pruritus. Trial registration ClinicalTrials.gov #NCT01792713. PMID:26527564

  2. Preoperative hyperfractionated chemoradiation for locally recurrent rectal cancer in patients previously irradiated to the pelvis: A multicentric phase II study

    SciTech Connect

    Valentini, Vincenzo . E-mail: vvalentini@rm.unicatt.it; Morganti, Alessio G.; Gambacorta, M. Antonietta; Mohiuddin, Mohammed; Doglietto, G. Battista; Coco, Claudio; De Paoli, Antonino; Rossi, Carlo; Di Russo, Annamaria; Valvo, Francesca; Bolzicco, Giampaolo; Dalla Palma, Maurizio

    2006-03-15

    Purpose: The combination of irradiation and total mesorectal excision for rectal carcinoma has significantly lowered the incidence of local recurrence. However, a new problem is represented by the patient with locally recurrent cancer who has received previous irradiation to the pelvis. In these patients, local recurrence is very often not easily resectable and reirradiation is expected to be associated with a high risk of late toxicity. The aim of this multicenter phase II study is to evaluate the response rate, resectability rate, local control, and treatment-related toxicity of preoperative hyperfractionated chemoradiation for locally recurrent rectal cancer in patients previously irradiated to the pelvis. Methods and Materials: Patients with histologically proven pelvic recurrence of rectal carcinoma, with the absence of extrapelvic disease or bony involvement and previous pelvic irradiation with doses {<=}55 Gy; age {>=}18 years; performance status (PS) (Karnofsky) {>=}60, and who gave institutional review board-approved written informed consent were treated by preoperative chemoradiation. Radiotherapy was delivered to a planning target volume (PTV2) including the gross tumor volume (GTV) plus a 4-cm margin, with a dose of 30 Gy (1.2 Gy twice daily with a minimum 6-h interval). A boost was delivered, with the same fractionation schedule, to a PTV1 including the GTV plus a 2-cm margin (10.8 Gy). During the radiation treatment, concurrent chemotherapy was delivered (5-fluorouracil, protracted intravenous infusion, 225 mg/m{sup 2}/day, 7 days per week). Four to 6 weeks after the end of chemoradiation, patients were evaluated for tumor resectability, and, when feasible, surgical resection of recurrence was performed between 6-8 weeks from the end of chemoradiation. Adjuvant chemotherapy was prescribed to all patients, using Raltitrexed, 3 mg/square meter (sm), every 3 weeks, for a total of 5 cycles. Patients were staged using the computed tomography (CT)-based F

  3. Glassy phases and driven response of the phase-field-crystal model with random pinning.

    PubMed

    Granato, E; Ramos, J A P; Achim, C V; Lehikoinen, J; Ying, S C; Ala-Nissila, T; Elder, K R

    2011-09-01

    We study the structural correlations and the nonlinear response to a driving force of a two-dimensional phase-field-crystal model with random pinning. The model provides an effective continuous description of lattice systems in the presence of disordered external pinning centers, allowing for both elastic and plastic deformations. We find that the phase-field crystal with disorder assumes an amorphous glassy ground state, with only short-ranged positional and orientational correlations, even in the limit of weak disorder. Under increasing driving force, the pinned amorphous-glass phase evolves into a moving plastic-flow phase and then, finally, a moving smectic phase. The transverse response of the moving smectic phase shows a vanishing transverse critical force for increasing system sizes. PMID:22060323

  4. NONLINEAR-OPTICS PHENOMENA: Phase fluctuations in waves reflected from a phase-conjugate mirror in a randomly inhomogeneous medium

    NASA Astrophysics Data System (ADS)

    Almaev, R. Kh; Suvorov, A. A.

    1993-09-01

    We investigate the statistical characteristics of the phase of a wave propagating along a ranging path that includes a phase-conjugate mirror through a medium whose complex permittivity ɛ varies randomly. We obtain expressions for the mean change and variance of fluctuations in the phase of a plane wave. We show that phase fluctuations caused by the random changes of the imaginary part of ɛ are not canceled by the phase-conjugate mirror. We obtain conditions for the appearance of enhanced backward scattering in comparison with the mean phase and variance of phase fluctuations for the reflected wave in this absorbing, randomly inhomogeneous medium.

  5. Hormone-Balancing Effect of Pre-Gelatinized Organic Maca (Lepidium peruvianum Chacon): (II) Physiological and Symptomatic Responses of Early-Postmenopausal Women to Standardized doses of Maca in Double Blind, Randomized, Placebo-Controlled, Multi-Centre Clinical Study

    PubMed Central

    Meissner, H. O.; Mscisz, A.; Reich-Bilinska, H.; Kapczynski, W.; Mrozikiewicz, P.; Bobkiewicz-Kozlowska, T.; Kedzia, B.; Lowicka, A.; Barchia, I.

    2006-01-01

    This was a double-blind, randomized, placebo-corrected, outpatient, multi-centre (five sites) clinical study, in which a total of 168 Caucasian early-postmenopausal women volunteers (age>49 years) participated after fulfilling the criteria: follicle stimulating hormone (FSH) >30 IU/ml and estrogen (E2) <40 pg/ml levels at admission. They were randomly allocated to Placebo and Pre-Gelatinized Organic Maca (Maca-GO) treatment, according to different monthly treatment sequences scheduled for each site. Two 500 mg vegetable hard gel capsules with Maca-GO or Placebo powder were self-administered twice daily with meals (total 2 g/day) during three (Trial I; n=102) or four (Trial II; n=66) months study periods. At the baseline and follow- up monthly intervals, blood levels of FSH, E2, progesterone (PRG) and lutinizing hormone (LH), as well as serum cholesterol (CHOL), triglycerides (TRG), high- and low density lipoproteins (HDL and LDL) were measured. Menopausal symptoms were assessed according to Greene’s Score (GMS) and Kupperman’s Index (KMI). Data were analyzed using multivariate technique on blocs of monthly results in one model and Maca versus Placebo contrast in another model. A total of 124 women concluded the study. Maca-GO significantly stimulated production of E2 (P<0.001) with a simultaneous suppression (P<0.05) of blood FSH, increase (P<0.05) in HDL. Maca-GO significantly reduced both frequency and severity of individual menopausal symptoms (hot flushes and night sweating in particular) resulting in significant (P<0.001) alleviation of KMI (from 22 to 10), thus, offering an attractive non-hormonal addition to the choices available to early-postmenopausal women in the form of a natural plant alternative to Hormone Replacement Therapy (HRT) – hence, reducing dependence on hormone therapy programs. PMID:23675005

  6. A mathematical formulation of the random phase approximation for crystals

    NASA Astrophysics Data System (ADS)

    Cancès, Eric; Stoltz, Gabriel

    2012-11-01

    This works extends the recent study on the dielectric permittivity of crystals within the Hartree model [E. Cances and M. Lewin, Arch. Rational Mech. Anal., 197 (2010) 139--177] to the time-dependent setting. In particular, we prove the existence and uniqueness of the nonlinear Hartree dynamics (also called the random phase approximation in the physics literature), in a suitable functional space allowing to describe a local defect embedded in a perfect crystal. We also give a rigorous mathematical definition of the microscopic frequency-dependent polarization matrix, and derive the macroscopic Maxwell-Gauss equation for insulating and semiconducting crystals, from a first order approximation of the nonlinear Hartree model, by means of homogenization arguments.

  7. Continuum random-phase approximation for relativistic point coupling models

    SciTech Connect

    Daoutidis, J.; Ring, P.

    2009-08-15

    Continuum relativistic random-phase approximation (CRPA) is used to investigate collective excitation phenomena in several spherical nuclei along the periodic table. We start from relativistic mean-field calculations based on a covariant density functional with density-dependent zero-range forces. From the same functional an effective interaction is obtained as the second derivative with respect to the density. This interaction is used in relativistic CRPA calculations for the investigation of isoscalar monopole, isovector dipole, and isoscalar quadrupole resonances of spherical nuclei. In particular we study the low-lying E1 strength in the vicinity of the neutron evaporation threshold. The properties of the resonances, such as centroid energies and strengths distributions are compared with results of discrete RPA calculations for the same model as well as with experimental data.

  8. Phase transitions in the coloring of random graphs.

    PubMed

    Zdeborová, Lenka; Krzakała, Florent

    2007-09-01

    We consider the problem of coloring the vertices of a large sparse random graph with a given number of colors so that no adjacent vertices have the same color. Using the cavity method, we present a detailed and systematic analytical study of the space of proper colorings (solutions). We show that for a fixed number of colors and as the average vertex degree (number of constraints) increases, the set of solutions undergoes several phase transitions similar to those observed in the mean field theory of glasses. First, at the clustering transition, the entropically dominant part of the phase space decomposes into an exponential number of pure states so that beyond this transition a uniform sampling of solutions becomes hard. Afterward, the space of solutions condenses over a finite number of the largest states and consequently the total entropy of solutions becomes smaller than the annealed one. Another transition takes place when in all the entropically dominant states a finite fraction of nodes freezes so that each of these nodes is allowed a single color in all the solutions inside the state. Eventually, above the coloring threshold, no more solutions are available. We compute all the critical connectivities for Erdos-Rényi and regular random graphs and determine their asymptotic values for a large number of colors. Finally, we discuss the algorithmic consequences of our findings. We argue that the onset of computational hardness is not associated with the clustering transition and we suggest instead that the freezing transition might be the relevant phenomenon. We also discuss the performance of a simple local Walk-COL algorithm and of the belief propagation algorithm in the light of our results. PMID:17930223

  9. Exploring the Random Phase Approximately for materials chemistry and physics

    SciTech Connect

    Ruzsinsky, Adrienn

    2015-03-23

    This proposal focuses on improved accuracy for the delicate energy differences of interest in materials chemistry with the fully nonlocal random phase approximation (RPA) in a density functional context. Could RPA or RPA-like approaches become standard methods of first-principles electronic-structure calculation for atoms, molecules, solids, surfaces, and nano-structures? Direct RPA includes the full exact exchange energy and a nonlocal correlation energy from the occupied and unoccupied Kohn-Sham orbitals and orbital energies, with an approximate but universal description of long-range van der Waals attraction. RPA also improves upon simple pair-wise interaction potentials or vdW density functional theory. This improvement is essential to capture accurate energy differences in metals and different phases of semiconductors. The applications in this proposal are challenges for the simpler approximations of Kohn-Sham density functional theory, which are part of the current “standard model” for quantum chemistry and condensed matter physics. Within this project we already applied RPA on different structural phase transitions on semiconductors, metals and molecules. Although RPA predicts accurate structural parameters, RPA has proven not equally accurate in all kinds of structural phase transitions. Therefore a correction to RPA can be necessary in many cases. We are currently implementing and testing a nonempirical, spatially nonlocal, frequency-dependent model for the exchange-correlation kernel in the adiabatic-connection fluctuation-dissipation context. This kernel predicts a nearly-exact correlation energy for the electron gas of uniform density. If RPA or RPA-like approaches prove to be reliably accurate, then expected increases in computer power may make them standard in the electronic-structure calculations of the future.

  10. Lafutidine 10 mg versus Rabeprazole 20 mg in the Treatment of Patients with Heartburn-Dominant Uninvestigated Dyspepsia: A Randomized, Multicentric Trial

    PubMed Central

    Dewan, Bhupesh; Philipose, Nisha

    2011-01-01

    Background. Empirical therapy with antisecretory agents like PPIs and H2RAs has long been the traditional approach in the initial management of uninvestigated dyspepsia. Aim. The objective of the study was to examine relief of dyspepsia with lafutidine, a second-generation H2-RA, and rabeprazole and to compare their efficacy. Methods. This was a randomized, open, comparative trial in adult uninvestigated dyspeptic patients, who had at least moderate severity of symptoms, defined as a score of ≥4 on a 7-point global overall symptom (GOS) scale, and were randomized to receive once daily either lafutidine 10 mg or rabeprazole 20 mg for 4 weeks. Results. A total of 236 patients were enrolled, out of which 194 patients were included in the analysis. At the end of week 4, a significant difference was observed for symptom relief (lafutidine 89.90% versus rabeprazole 65.26%, P < .01) and symptom resolution (lafutidine 70.71% versus rabeprazole 25.26%, P < .01). Both the drugs were well tolerated. Conclusion. Both lafutidine and rabeprazole provide symptom relief in patients with heartburn-dominant uninvestigated dyspepsia. The present study confirms the appropriateness of lafutidine as an empiric treatment and superior efficacy for primary care practice patients with dyspepsia. PMID:21687618

  11. Web-based screening and brief intervention for poly-drug use among teenagers: study protocol of a multicentre two-arm randomized controlled trial

    PubMed Central

    2012-01-01

    Background Mid to late adolescence is characterised by a vulnerability to problematic substance use since the consumption of alcohol and illicit drugs is frequently initiated and increased in this life period. While the detrimental long- and short-term effects of problematic consumption patterns in adolescence pose a major public health concern, current prevention programs targeting alcohol- and other substance-using adolescents are scarce. The study described in this protocol will test the effectiveness of a web-based brief intervention aimed at reducing problematic alcohol use and promoting abstinence from illegal drugs in adolescents with risky substance use aged 16 to 18 years old in four EU-countries. Methods/design To determine the effectiveness of our web-BI, we apply a two-arm randomized controlled trial (RCT) study design, with baseline assessment at study entry and a three month follow-up assessment. Adolescents aged 16 to 18 years from Belgium, the Czech Republic, Germany, and Sweden will be randomly assigned to either the fully electronically delivered brief intervention group (N = 400) or an assessment only control group (N = 400) depending on their screening for risky substance use (using the CRAFFT). Recruitment, informed consent, randomization, intervention and follow-up will be implemented online. Primary outcomes are reductions in frequency and quantity of use of alcohol and drugs other than alcohol over a 30 day period, as well as consumption per typical occasion. Secondary outcomes concern changes in substance use related cognitions including the constructs of the Theory of Planned Behaviour, implementation intentions, and stages of change. Moreover the study addresses a number of moderator variables, including age of first use, general psychopathology and quality of parent–child relationship. Discussion The trial is expected to contribute to the growing literature on theory- and web-based brief interventions for adolescents. We will

  12. Postradiation multicentric osteosarcoma

    SciTech Connect

    Tillotson, C.; Rosenberg, A.; Gebhardt, M.; Rosenthal, D.I.

    1988-07-01

    The oncogenic effects of radiation are well-established. Osteosarcomas and fibrosarcomas are the two most common histologic types of secondary sarcoma. In this article a case of postradiation osteosarcoma is presented in which four discrete foci of sarcomatous transformation have occurred in the tibia and fibula after irradiation for a rhabdomyosarcoma of the calf 8 years earlier. A review of the literature reveals no similar case. Although synchronous, multifocal osteosarcoma without prior radiation has been described, this case differs in clinical, radiographic, and pathologic features; it best fits the description of postradiation multicentric osteosarcoma.

  13. Predicting the Catalytic Reactions using Random Phase Approximation

    NASA Astrophysics Data System (ADS)

    Yan, J.; Olsen, T.; Mortensen, J. J.; Jacobsen, K. W.; Thygesen, K. S.; Abild-Pedersen, F.; Norskov, J. K.

    2012-02-01

    Density functional theory has became the workhorse for simulations of catalytic reactions and computational design of novel catalysis. The generally applied semi-local exchange-correlation functionals have successfully predicted catalytic reaction trends over a variety of surfaces. However, in order to achieve quantitative predictions of reaction rates for molecule-surface systems, in particular where there is weak Van der Waals interactions or strong correlation, it is of vital importance to include non-local correlation effects. The use of random phase approximation (RPA) to construct the correlation energy, combined with the exact, self-interaction free exchange energy, offers a non-empirical way for accurately describe the adsorption energies [1] and dispersion forces [2]. We have recently implemented RPA in the GPAW code [3-4], an electronic structure package using projector augmented wave method and real space grids. In this talk I will present our initial results comparing RPA and generalized gradient functionals for the activation energies and reaction energies for transition metal or metal oxide surfaces. [4pt] [1] L. Schimka, et.al, Nature Mat. 9, 741 (2010) [2] T. Olsen, et.al, Phys. Rev. Lett. 107, 156401 (2011) [3] J. Yan, et.al, Phys. Rev. B 83, 245122 (2011). [4] J. Yan, et.al, Phys. Rev. Lett. 106, 146803 (2011)

  14. Random Phase Approximation in Surface Chemistry: Water Splitting on Iron.

    PubMed

    Karlický, František; Lazar, Petr; Dubecký, Matúš; Otyepka, Michal

    2013-08-13

    The reaction of water with zero-valent iron (anaerobic corrosion) is a complex chemical process involving physisorption and chemisorption events. We employ random phase approximation (RPA) along with gradient-corrected and hybrid density functional theory (DFT) functionals to study the reaction of water with the Fe atom and Fe(100) surface. We show that the involvement of the exact electron exchange and nonlocal correlation effects in RPA improves the description of all steps of the reaction on the Fe surface with respect to standard [meaning local density approximation (LDA) or generalized gradient approximation (GGA)] DFT methods. The reaction profile calculated by range-separated hybrid functional HSE06 agrees reasonably well with the RPA profile, which makes HSE06 a computationally less demanding alternative to RPA. We also investigate the reaction of the Fe atom with water using DFT, RPA, and coupled-cluster through the perturbative triples complete basis set [CCSD(T)-3s3p-DKH/CBS] method. Local DFT methods significantly underestimate reaction barriers, while the reaction kinetics and thermodynamics from RPA agree with the reference CCSD(T) data. Both systems, i.e., the Fe atom and Fe(100), provide the same reaction mechanism, indicating that anaerobic corrosion is a stepwise process involving one-electron steps, with the first reaction step (formation of the HFeOH intermediate) representing the rate-limiting step. PMID:26584120

  15. Separable pairing force for relativistic quasiparticle random-phase approximation

    SciTech Connect

    Tian Yuan; Ma Zhongyu; Ring, Peter

    2009-06-15

    We have introduced a separable pairing force, which was adjusted to reproduce the pairing properties of the Gogny force in nuclear matter. This separable pairing force is able to describe in relativistic Hartree-Bogoliubov (RHB) calculations the pairing properties in the ground state of finite nuclei on almost the same footing as the original Gogny interaction. In this work we investigate excited states using the Relativistic Quasiparticle Random-Phase Approximation (RQRPA) with the same separable pairing force. For consistency the Goldstone modes and the convergence with various cutoff parameters in this version of RQRPA are studied. The first excited 2{sup +} states for the chain of Sn isotopes with Z=50 and the chain of isotones with N=82 isotones are calculated in RQRPA together with the 3{sup -} states of Sn isotopes. By comparing our results with experimental data and with the results of the original Gogny force we find that this simple separable pairing interaction is very successful in depicting the pairing properties of vibrational excitations.

  16. Communication: Random phase approximation renormalized many-body perturbation theory

    SciTech Connect

    Bates, Jefferson E.; Furche, Filipp

    2013-11-07

    We derive a renormalized many-body perturbation theory (MBPT) starting from the random phase approximation (RPA). This RPA-renormalized perturbation theory extends the scope of single-reference MBPT methods to small-gap systems without significantly increasing the computational cost. The leading correction to RPA, termed the approximate exchange kernel (AXK), substantially improves upon RPA atomization energies and ionization potentials without affecting other properties such as barrier heights where RPA is already accurate. Thus, AXK is more balanced than second-order screened exchange [A. Grüneis et al., J. Chem. Phys. 131, 154115 (2009)], which tends to overcorrect RPA for systems with stronger static correlation. Similarly, AXK avoids the divergence of second-order Møller-Plesset (MP2) theory for small gap systems and delivers a much more consistent performance than MP2 across the periodic table at comparable cost. RPA+AXK thus is an accurate, non-empirical, and robust tool to assess and improve semi-local density functional theory for a wide range of systems previously inaccessible to first-principles electronic structure calculations.

  17. Lamivudine in late pregnancy to prevent perinatal transmission of hepatitis B virus infection: a multicentre, randomized, double-blind, placebo-controlled study.

    PubMed

    Xu, W-M; Cui, Y-T; Wang, L; Yang, H; Liang, Z-Q; Li, X-M; Zhang, S-L; Qiao, F-Y; Campbell, F; Chang, C-N; Gardner, S; Atkins, M

    2009-02-01

    This randomized, double-blind, placebo-controlled study evaluated whether lamivudine given during late pregnancy can reduce hepatitis B virus (HBV) perinatal transmission in highly viraemic mothers. Mothers were randomized to either lamivudine 100 mg or placebo from week 32 of gestation to week 4 postpartum. At birth, infants received recombinant HBV vaccine with or without HBIg and were followed until week 52. One hundred and fifty mothers, with a gestational age of 26-30 weeks and serum HBV DNA >1000 MEq/mL (bDNA assay), were treated. A total of 141 infants received immunoprophylaxis at birth. In lamivudine-treated mothers, 56 infants received vaccine + HBIg (lamivudine + vaccine + HBIg) and 26 infants received vaccine (lamivudine + vaccine). In placebo-treated mothers, 59 infants received vaccine + HBIg (placebo + vaccine + HBIg). At week 52, in the primary analyses where missing data was counted as failures, infants in the lamivudine + vaccine + HBIg group had a significant decrease in incidence of HBsAg seropositivity (10/56, 18%vs 23/59, 39%; P = 0.014) and in detectable HBV DNA (11/56, 20%vs 27/59, 46%; P = 0.003) compared to infants in the placebo + vaccine + HBIg group. Sensitivity analyses to evaluate the impact of missing data at week 52 resulting from a high dropout rate (13% in the lamivudine + vaccine + HBIg group and 31% in the placebo + vaccine + HBIg group) remained consistent with the primary analysis in that lower transmission rates were still observed in the infants of lamivudine-treated mothers, but the differences were not statistically significant. No safety concerns were noted in the lamivudine-treated mothers or their infants. Results of this study suggest that lamivudine reduced HBV transmission from highly viraemic mothers to their infants who received passive/active immunization. PMID:19175878

  18. Betamethasone valerate dressing is non-inferior to calcipotriol–betamethasone dipropionate ointment in the treatment of patients with mild-to-moderate chronic plaque psoriasis: results of a randomized assessor-blinded multicentre trial

    PubMed Central

    Ortonne, J-P; Esposito, M; Chimenti, S; Kapińska-Mrowiecka, M; Grodzińska, A; Naldi, L; Frangione, V

    2014-01-01

    Background A ready-to-use betamethasone valerate 0.1% (BMV) dressing was found to be superior to placebo dressing and a reference 0.1% BMV cream in the treatment of patients with chronic plaque psoriasis (CPP). Methods This multicentre, prospective, randomized, investigator-blinded, controlled, non-inferiority trial compared the efficacy and safety of the BMV dressing to the calcipotriol–betamethasone dipropionate (CBD) ointment during a 4-week treatment of patients with mild to moderate CPP. The primary efficacy endpoint was the 4-item psoriasis total severity score (TSS-4) at week 4, and the associated non-inferiority margin was 1 point. Secondary outcome measures included the psoriasis global assessment (PGA) score and patients’ quality of life (QoL). Safety was assessed through adverse events (AE) reporting in each treatment group. Results Of 325 screened patients, 324 were randomized to BMV (N = 165) or CBD (N = 159), and were considered evaluable for the safety and intention-to-treat (ITT) efficacy analyses. Per protocol (PP) populations included 133 and 131 patients in the BMV and CBD groups respectively. The mean adjusted TSS-4 significantly decreased through the study from baseline in both groups. The PP (primary) analysis of week 4 data revealed a −0.288 (95% CI: −0.610 to 0.034) not significant between-group difference in adjusted means, demonstrating non-inferiority of BMV to CBD. Non-inferiority was also demonstrated in the ITT analysis. The PGA and other secondary outcomes were significantly improved from baseline in both groups at week 4. The QoL score was slightly better in the CBD group at week 4, but no difference was observed at follow-up. No safety or tolerability concerns were observed in either group. Conflicts of interest Centro Studi GISED, the centre led by LN, received a grant from IBSA Institut Biochimique SA. VF is an employee of IBSA Institut Biochimique SA. PMID:24256460

  19. Safety and efficacy of multipolar pulmonary vein ablation catheter vs. irrigated radiofrequency ablation for paroxysmal atrial fibrillation: a randomized multicentre trial

    PubMed Central

    McCready, J.; Chow, A. W.; Lowe, M. D.; Segal, O. R.; Ahsan, S.; de Bono, J.; Dhaliwal, M.; Mfuko, C.; Ng, A.; Rowland, E. R.; Bradley, R. J. W.; Paisey, J.; Roberts, P.; Morgan, J. M.; Sandilands, A.; Yue, A.; Lambiase, P. D.

    2014-01-01

    Aims The current challenge in atrial fibrillation (AF) treatment is to develop effective, efficient, and safe ablation strategies. This randomized controlled trial assesses the medium-term efficacy of duty-cycled radiofrequency ablation via the circular pulmonary vein ablation catheter (PVAC) vs. conventional electro-anatomically guided wide-area circumferential ablation (WACA). Methods and results One hundred and eighty-eight patients (mean age 62 ± 12 years, 116 M : 72 F) with paroxysmal AF were prospectively randomized to PVAC or WACA strategies and sequentially followed for 12 months. The primary endpoint was freedom from symptomatic or documented >30 s AF off medications for 7 days at 12 months post-procedure. One hundred and eighty-three patients completed 12 m follow-up. Ninety-four patients underwent PVAC PV isolation with 372 of 376 pulmonary veins (PVs) successfully isolated and all PVs isolated in 92 WACA patients. Three WACA and no PVAC patients developed tamponade. Fifty-six percent of WACA and 60% of PVAC patients were free of AF at 12 months post-procedure (P = ns) with a significant attrition rate from 77 to 78%, respectively, at 6 months. The mean procedure (140 ± 43 vs. 167 ± 42 min, P<0.0001), fluoroscopy (35 ± 16 vs. 42 ± 20 min, P<0.05) times were significantly shorter for PVAC than for WACA. Two patients developed strokes within 72 h of the procedure in the PVAC group, one possibly related directly to PVAC ablation in a high-risk patient and none in the WACA group (P = ns). Two of the 47 patients in the PVAC group who underwent repeat ablation had sub-clinical mild PV stenoses of 25–50% and 1 WACA patient developed delayed severe PV stenosis requiring venoplasty. Conclusion The pulmonary vein ablation catheter is equivalent in efficacy to WACA with reduced procedural and fluoroscopy times. However, there is a risk of thrombo-embolic and pulmonary stenosis complications which needs to be addressed and prospectively monitored. Clinical

  20. Preventive effect of Malva on urinary toxicity after radiation therapy in prostate cancer patients: A multi-centric, double-blind, randomized clinical trial

    PubMed Central

    Mofid, Bahram; Rezaeizadeh, Hossein; Jaladat, Amir Mohammad; Atarzadeh, Fatemeh; Moeini, Reihane; Motevalian, Abbas; Mosalaie, Ahmad; Farhan, Farshid; Rakhsha, Afshin; Kashi, Amir Shahram Yousefi

    2015-01-01

    Background: For patients receiving external beam radiation therapy (EBRT) after radical prostatectomy as adjuvant treatment or patients receiving EBRT as definitive treatment, partial irradiation of the urinary bladder is common. Many of such patients experience some degree of radiation-induced cystitis during or after EBRT. There is currently no efficient treatment for preventing radiation cystitis. Objective: The aim of this study was to evaluate the effectiveness of one of the safe mucilaginous herbs (Malva) in preventing radiation-induced dysuria in patients who are undergoing EBRT for prostate cancer. Methods: From April 2013 to August 2014, 68 patients were randomized into two groups using four block randomization, 34 to the drug (Malva) group and 34 to the placebo group. Of the 68 patients who began the study, 60 completed it. They were instructed to use the medication, i.e., Malva or the placebo, three times a day for six weeks. They were followed by a physician every two weeks for eight weeks, and urinary function was assessed in each visit by asking questions based on the Visual Prostate Symptom Score (VPSS) and a dysuria severity score. The changes in the VPSS and dysuria severity score between baseline and each follow-up visit were compared between the two groups in the study using repeated measures analysis of variance (ANOVA) and t-tests. Results: The median age of the 68 patients was 66. Twenty-one of 27 patients in the control group (77.7%) suffered from dysuria, while dysuria was detected in 23 of 33 patients (69.6%) who received Malva (odds ratio=2.70 for dysuria). After two weeks, four weeks, and six weeks of treatment with Malva, dysuria due to EBRT was milder in the treatment group than in the control group, and the differences were statistically significant (p = 0.005, p = 0.004, p = 0.001, respectively). Conclusion: To the best of our knowledge, our study is the first study to assess the protective effect of a mucilaginous herb (Malva

  1. Polyadenylic-polyuridylic acid as an adjuvant in resectable colorectal carcinoma: a 6 1/2 year follow-up analysis of a multicentric double blind randomized trial.

    PubMed

    Lacour, J; Laplanche, A; Malafosse, M; Gallot, D; Julien, M; Rotman, N; Guivarc'h, M; Roullet-Audy, J C; Lasser, P; Hautefeuille, P

    1992-12-01

    In a double blind study, patients with operable carcinoma of the colon and the upper rectum, who have undergone a macroscopically complete resection of their tumor, were randomized to receive either (i) polyadenylic-polyuridylic acid (AU), one i.v. injection of 60 mg (in 50 ml of solution) once a week for 6 weeks, or (ii) a placebo (P) one i.v. injection of 50 ml of a saline solution with the same schedule. From January 1983 to December 1986, 288 patients were enrolled: 145 in AU group and 143 in P group. The main clinical and pathological characteristics were equally distributed throughout the two groups. There was a significant difference (P < 0.02) in the overall survival (OS) between the two groups, in favor of the P group. The 5-year OS rate was 68% (SD = 4%) in the AU group versus 81% (SD = 3%) in the P group. Thus, AU as a single adjuvant, appears to be ineffective and therefore has no indication in the treatment of colorectal carcinoma. PMID:1478293

  2. Efficacy of Diosmectite (Smecta)® in the Treatment of Acute Watery Diarrhoea in Adults: A Multicentre, Randomized, Double-Blind, Placebo-Controlled, Parallel Group Study

    PubMed Central

    Khediri, Faouzi; Mrad, Abdennebi Ilhem; Azzouz, Moussadek; Doughi, Hedi; Najjar, Taoufik; Mathiex-Fortunet, Hélène; Garnier, Philippe; Cortot, Antoine

    2011-01-01

    Background. Although diosmectite has demonstrated efficacy in the treatment of acute watery diarrhoea in children, its efficacy in adults still needs to be assessed. The objective of this study was therefore to assess the efficacy of diosmectite on the time to recovery in adults with acute diarrhoea. Methods. A total of 346 adults with at least three watery stools per day over a period of less than 48 hours were prospectively randomized to diosmectite (6 g tid) or placebo during four days. The primary endpoint was time to diarrhoea recovery. Results. In the intention-to-treat population, median time to recovery was 53.8 hours (range [3.7–167.3]) with diosmectite (n = 166) versus 69.0 hours [2.2–165.2] with placebo, (n = 163; P = .029), which corresponds to a difference of 15.2 hours. Diosmectite was well tolerated. Conclusion. Diosmectite at 6 g tid was well tolerated and reduced the time to recovery of acute watery diarrhoea episode in a clinically relevant manner. PMID:21760777

  3. Efficacy and Safety of Low-Dose Cyclosporine with Everolimus and Steroids in de novo Heart Transplant Patients: A Multicentre, Randomized Trial

    PubMed Central

    Zuckermann, Andreas; Wang, Shoei-Shen; Ross, Heather; Frigerio, Maria; Eisen, Howard J.; Bara, Christoph; Hoefer, Daniel; Cotrufo, Maurizio; Dong, Gaohong; Junge, Guido; Keogh, Anne M.

    2011-01-01

    A six-month, multicenter, randomized, open-label study was undertaken to determine whether renal function is improved using reduced-exposure cyclosporine (CsA) versus standard-exposure CsA in 199 de novo heart transplant patients receiving everolimus and steroids ± induction therapy. Mean C2 levels were at the low end of the target range in standard-exposure patients (n = 100) and exceeded target range in reduced-exposure patients (n = 99) throughout the study. Mean serum creatinine at Month 6 (the primary endpoint) was 141.0 ± 53.1 μmol/L in standard-exposure patients versus 130.1 ± 53.7 μmol/L in reduced-exposure patients (P = 0.093). The incidence of biopsy-proven acute rejection ≥3A at Month 6 was 21.0% (21/100) in the standard-exposure group and 16.2% (16/99) in the reduced-exposure group (n.s.). Adverse events and infections were similar between treatment groups. Thus, everolimus with reduced-exposure CsA resulted in comparable efficacy compared to standard-exposure CsA. No renal function benefits were demonstrated; that is possibly related to poor adherence to reduced CsA exposure. PMID:22295178

  4. Descriptive analysis of the prevalence of anemia in a randomly selected sample of elderly people living at home: some results of an Italian multicentric study.

    PubMed

    Inelmen, E M; D'Alessio, M; Gatto, M R; Baggio, M B; Jimenez, G; Bizzotto, M G; Enzi, G

    1994-04-01

    We studied hematological indexes (RBC, HB, HT, MCV), serum iron and serum ferritin values in 1784 randomly selected subjects aged 65 and over (725 males and 1059 females) divided into five age groups (65-69, 70-74, 75-79, 80-84, > or = 85 years). The subjects were classified as anemic and normochromic according to the criteria for a "geriatric" level of anemia (HB < or = 12 g/dL in both sexes) as well as "W.H.O." levels for anemia (HB < 13 g/dL in males and < 12 g/dL in females). Macrocytosis (MCV > 100 fl) and low serum ferritin level (< or = 12 ng/dL) were classified according to MCV and serum ferritin values. Mean HB values in males were 14.85 +/- 1.33; 14.82 +/- 1.40; 14.77 +/- 1.43; 14.59 +/- 1.47 and 13.83 +/- 1.13 in the five age groups (65-69, 70-74, 75-79, 80-84 and > or = 85 years) respectively; in females, they were 13.77 +/- 1.15; 13.75 +/- 1.27; 13.44 +/- 1.39; 13.44 +/- 1.52 and 13.34 +/- 1.61, respectively. There was a low frequency of anemia in the entire sample: 2.9% in males and 9.9% in females according to the "geriatric" level, and 9.4% in males and 8.8% in females according to the "W.H.O." level. There was a higher prevalence of macrocytosis in males (6.3%) than in females (3.3%). We conclude that red cell parameters tend to decrease in aging, and further investigations are needed that exclude persons with existing chronic conditions, and incorporate data on nutritional status. PMID:7918735

  5. The INCH-Trial: a multicentre randomized controlled trial comparing the efficacy of conventional open surgery and laparoscopic surgery for incisional hernia repair

    PubMed Central

    2013-01-01

    Background Annually approximately 100.000 patients undergo a laparotomy in the Netherlands. About 15,000 of these patients will develop an incisional hernia. Both open and laparoscopic surgical repair have been proven to be safe. However, the most effective treatment of incisional hernias remains unclear. This study, the ‘INCH-trial’, comparing cost-effectiveness of open and laparoscopic incisional hernia repair, is therefore needed. Methods/Design A randomized multi-center clinical trial comparing cost-effectiveness of open and laparoscopic repair of incisional hernias. Patients with a symptomatic incisional hernia, eligible for laparoscopic and open incisional hernia repair. Only surgeons, experienced in both open and laparoscopic incisional hernia repair, will participate in the INCH trial. During incisional hernia repair, a mesh is placed under or on top of the fascia, with a minimal overlap of 5 cm. Primary endpoint is length of hospital stay after an incisional hernia repair. Secondary endpoints are time to full recovery within three months after index surgery, post-operative complications, recurrences, mortality and quality of life. Our hypothesis is that laparoscopic incisional hernia repair comes with a significant shorter hospital stay compared to open incisional hernia repair. A difference of two days is considered significant. One-hunderd-and-thirty-five patients are enrolled in each treatment arm. The economic evaluation will be performed from a societal perspective. Primary outcomes are costs per patient related to time-to-recovery and quality of life. The main goal of the trial is to establish whether laparoscopic incisional hernia repair is superior to conventional open incisional hernia repair in terms of cost-effectiveness. This is measured through length of hospital stay and quality of life. Secondary endpoints are re-operation rate due to post-operative complications or recurrences, mortality and quality of life. Discussion The difference

  6. Group B streptococcus vaccination in pregnant women with or without HIV in Africa: a non-randomised phase 2, open-label, multicentre trial

    PubMed Central

    Heyderman, Robert S; Madhi, Shabir A; French, Neil; Cutland, Clare; Ngwira, Bagrey; Kayambo, Doris; Mboizi, Robert; Koen, Anthonet; Jose, Lisa; Olugbosi, Morounfolu; Wittke, Frederik; Slobod, Karen; Dull, Peter M

    2016-01-01

    Summary Background Neonates born to women infected with HIV are at increased risk for invasive group B streptococcus (GBS) disease. We aimed to compare safety and immunogenicity of trivalent glycoconjugate GBS vaccine in pregnant women with and without HIV in Malawi and South Africa. Methods In our non-randomised phase 2, open-label, multicentre study, we recruited pregnant women attending two antenatal clinics, one in Blantyre, Malawi, and one in Soweto, Johannesburg, South Africa. Participants were divided into three groups on the basis of their HIV infection status (no infection, infection and high CD4 cell count [>350 cells per μL], and infection and low CD4 cell count [>50 to ≤350 cells per μL]) and received a 5 μg dose of glycoconjugate GBS vaccine (serotypes Ia, Ib, and III, with CRM197 [Novartis Vaccines, Siena, Italy]) intramuscularly at 24–35 weeks' gestation. GBS serotype-specific antibody concentrations were measured before vaccination (day 1), day 15, day 31, and at delivery, and in infants at birth and day 42 of life. The primary outcomes were safety in mothers and infants and the amount of placental transfer of GBS serotype-specific antibodies from mothers to their infants. All immunogenicity and safety analyses were done on the full analysis set, including participants who, or whose mother, correctly received the vaccine and who provided at least one valid assessable serum sample. This study is registered with ClinicalTrials.gov, number NCT01412801. Findings 270 women and 266 infants were enrolled between Sept 26, 2011, and Dec 4, 2012 (90 women and 87 infants without HIV, 89 and 88 with HIV and high CD4 cell counts, and 91 and 91 with HIV and low CD4 cell counts, respectively). Seven women were lost to follow-up, six withdrew consent, one died, and two relocated. Eight infants died or were stillborn and two were lost to follow-up. Across serotypes, fold change in antibody concentrations were higher for the HIV-uninfected group than the HIV

  7. Electron correlation effects beyond the random phase approximation

    NASA Astrophysics Data System (ADS)

    Fan, J. D.; Malozovsky, Y. M.

    2016-04-01

    The methods that have been used to deal with a many-particle system can be basically sorted into three types: Hamiltonian, field theory and phenomenological method. The first two methods are more popular. Traditionally, the Hamiltonian method has been widely adopted in the conventional electronic theory for metals, alloys and semiconductors. Basically, the mean-field approximation (MFA) that has been working well for a weakly coupled system like a metal is employed to simplify a Hamiltonian corresponding to a particular electron system. However, for a strongly coupled many-particle system like a cuprate superconductor MFA should in principle not apply. Therefore, the field theory on the basis of Green’s function and the Feynman diagrams must be invoked. In this method, one is however more familiar with the random phase approximation (RPA) that gives rise to the same results as MFA because of being short of the information for higher-order terms of interaction. For a strongly coupled electron system, it is obvious that one has to deal with higher-order terms of a pair interaction to get a correct solution. Any ignorance of the higher-order terms implies that the more sophisticated information contained in those terms is discarded. However, to date one has not reached a consensus on how to deal with the higher-order terms beyond RPA. We preset here a method that is termed the diagrammatic iteration approach (DIA) and able to derive higher-order terms of the interaction from the information of lower-order ones on the basis of Feynman diagram, with which one is able to go beyond RPA step by step. It is in principle possible that all of higher-order terms can be obtained, and then sorted to groups of diagrams. It turns out that each of the groups can be replaced by an equivalent one, forming a diagrammatic Dyson-equation-like relation. The diagrammatic solution is eventually “translated” to a four-dimensional integral equation. The method can be applied to a

  8. Truly random number generation based on measurement of phase noise of a laser.

    PubMed

    Guo, Hong; Tang, Wenzhuo; Liu, Yu; Wei, Wei

    2010-05-01

    We present a simple approach to realize truly random number generator based on measuring the phase noise of a single-mode vertical cavity surface emitting laser. The true randomness of the quantum phase noise originates from the spontaneous emission of photons and the random bit generation rate is ultimately limited only by the laser linewidth. With the final bit generation rate of 20 Mbit/s, the truly random bit sequence guaranteed by the uncertainty principle of quantum mechanics passes the three standard randomness tests (ENT, Diehard, and NIST Statistical Test Suites). Moreover, a continuously generated random bit sequence, with length up to 14 Gbit, is verified by two additional criteria for its true randomness. PMID:20866215

  9. Phase transition in the assignment problem for random matrices

    NASA Astrophysics Data System (ADS)

    Esteve, J. G.; Falceto, F.

    2005-12-01

    We report an analytic and numerical study of a phase transition in a P problem (the assignment problem) that separates two phases whose representatives are the simple matching problem (an easy P problem) and the traveling-salesman problem (a NP-complete problem). Like other phase transitions found in combinatoric problems (K-satisfiability, number partitioning) this can help to understand the nature of the difficulties in solving NP problems an to find more accurate algorithms for them.

  10. Anomalously elastic intermediate phase in randomly layered superfluids, superconductors, and planar magnets.

    PubMed

    Mohan, Priyanka; Goldbart, Paul M; Narayanan, Rajesh; Toner, John; Vojta, Thomas

    2010-08-20

    We show that layered quenched randomness in planar magnets leads to an unusual intermediate phase between the conventional ferromagnetic low-temperature and paramagnetic high-temperature phases. In this intermediate phase, which is part of the Griffiths region, the spin-wave stiffness perpendicular to the random layers displays anomalous scaling behavior, with a continuously variable anomalous exponent, while the magnetization and the stiffness parallel to the layers both remain finite. Analogous results hold for superfluids and superconductors. We study the two phase transitions into the anomalous elastic phase, and we discuss the universality of these results, and implications of finite sample size as well as possible experiments. PMID:20868107

  11. Partition function for a two dimensional plasma in the random phase approximation

    NASA Technical Reports Server (NTRS)

    Seyler, C. E., Jr.

    1974-01-01

    The partition function for a two-dimensional plasma is evaluated within the random phase approximation. The periodic boundary conditions are fully taken into account by including the periodic image interactions. In the guiding-center limit, the negative temperature threshold energy is evaluated, and a value different from previous calculations results. When an identical random phase evaluated, and a value different from previous calculations results. When an identical random phase evaluation is applied to the finite gyroradius plasma, the Salzberg-Prager-May equation of state is recovered.

  12. Ultra-fast quantum randomness generation by accelerated phase diffusion in a pulsed laser diode.

    PubMed

    Abellán, C; Amaya, W; Jofre, M; Curty, M; Acín, A; Capmany, J; Pruneri, V; Mitchell, M W

    2014-01-27

    We demonstrate a high bit-rate quantum random number generator by interferometric detection of phase diffusion in a gain-switched DFB laser diode. Gain switching at few-GHz frequencies produces a train of bright pulses with nearly equal amplitudes and random phases. An unbalanced Mach-Zehnder interferometer is used to interfere subsequent pulses and thereby generate strong random-amplitude pulses, which are detected and digitized to produce a high-rate random bit string. Using established models of semiconductor laser field dynamics, we predict a regime of high visibility interference and nearly complete vacuum-fluctuation-induced phase diffusion between pulses. These are confirmed by measurement of pulse power statistics at the output of the interferometer. Using a 5.825 GHz excitation rate and 14-bit digitization, we observe 43 Gbps quantum randomness generation. PMID:24515170

  13. Chiral random grain boundary phase of achiral hockey-stick liquid crystals.

    PubMed

    Chen, Dong; Wang, Haitao; Li, Min; Glaser, Matthew A; Maclennan, Joseph E; Clark, Noel A

    2014-12-01

    A disordered chiral conglomerate, the random grain boundary (RGB) phase, has been observed below the smectic A liquid crystal phase of an achiral, hockey-stick molecule. In cells, the RGB phase appears dark between crossed polarizers but decrossing the polarizers reveals large left- and right-handed chiral domains with opposite optical rotation. Freeze-fracture transmission electron microscopy reveals that the RGB phase is an assembly of randomly oriented blocks of smectic layers, an arrangement that distinguishes the RGB from the dark, chiral conglomerate phases of bent-core mesogens. X-ray diffraction indicates that there is significant layer shrinkage at the SmA-RGB phase transition, which is marked by the collapse of layers with long-range order into small, randomly oriented smectic blocks. PMID:25310113

  14. Variance of phase fluctuations of waves propagating through a random medium

    NASA Technical Reports Server (NTRS)

    Chu, Nelson C.; Kong, Jin AU; Yueh, Simon H.; Nghiem, Son V.; Fleischman, Jack G.; Ayasli, Serpil; Shin, Robert T.

    1992-01-01

    As an electromagnetic wave propagates through a random scattering medium, such as a forest, its energy is attenuated and random phase fluctuations are induced. The magnitude of the random phase fluctuations induced is important in estimating how well a Synthetic Aperture Radar (SAR) can image objects within the scattering medium. The two-layer random medium model, consisting of a scattering layer between free space and ground, is used to calculate the variance of the phase fluctuations induced between a transmitter located above the random medium and a receiver located below the random medium. The scattering properties of the random medium are characterized by a correlation function of the random permittivity fluctuations. The effective permittivity of the random medium is first calculated using the strong fluctuation theory, which accounts for large permittivity fluctuations of the scatterers. The distorted Born approximation is used to calculate the first-order scattered field. A perturbation series for the phase of the received field in the Rytov approximation is then introduced and the variance of the phase fluctuations is also calculated assuming that the transmitter and receiver are in the paraxial limit of the random medium, which allows an analytic solution to be obtained. Results are compared using the paraxial approximation, scalar Green's function formulation, and dyadic Green's function formulation. The effects studied are the dependence of the variance of the phase fluctuations on receiver location in lossy and lossless regions, medium thickness, correlation length and fractional volume of scatterers, depolarization of the incident wave, ground layer permittivity, angle of incidence, and polarization.

  15. Self-consistent continuum random-phase approximation calculations with finite-range interactions

    SciTech Connect

    De Donno, V.; Co', G.; Anguiano, M.; Lallena, A. M.

    2011-04-15

    We present a technique that treats, without approximations, the continuum part of the excitation spectrum in random phase approximation calculations with finite-range interactions. The interaction used in Hartree-Fock calculations to generate the single-particle basis is also used in continuum random phase approximation calculations. We show results for electric dipole and quadrupole excitations in {sup 16}O, {sup 22}O, {sup 24}O, {sup 40}Ca, {sup 48}Ca, and {sup 52}Ca nuclei. We compare our results with those of the traditional discrete random phase approximation, with continuum independent-particle model results, and with results obtained by a phenomenological random phase approximation approach. We study the relevance of the continuum, of the residual interaction, and of the self-consistency. We also compare our results with the available total photoabsorption cross-section data.

  16. Phase-change Random Access Memory: A Scalable Technology

    SciTech Connect

    Raoux, S.; Burr, G; Breitwisch, M; Rettner, C; Chen, Y; Shelby, R; Salinga, M; Krebs, D; Chen, S; Lung, H

    2008-01-01

    Nonvolatile RAM using resistance contrast in phase-change materials [or phase-change RAM (PCRAM)] is a promising technology for future storage-class memory. However, such a technology can succeed only if it can scale smaller in size, given the increasingly tiny memory cells that are projected for future technology nodes (i.e., generations). We first discuss the critical aspects that may affect the scaling of PCRAM, including materials properties, power consumption during programming and read operations, thermal cross-talk between memory cells, and failure mechanisms. We then discuss experiments that directly address the scaling properties of the phase-change materials themselves, including studies of phase transitions in both nanoparticles and ultrathin films as a function of particle size and film thickness. This work in materials directly motivated the successful creation of a series of prototype PCRAM devices, which have been fabricated and tested at phase-change material cross-sections with extremely small dimensions as low as 3 nm x 20 nm. These device measurements provide a clear demonstration of the excellent scaling potential offered by this technology, and they are also consistent with the scaling behavior predicted by extensive device simulations. Finally, we discuss issues of device integration and cell design, manufacturability, and reliability.

  17. Phase transitions, magnetism and surface adsorptions assessed by meta-GGA functionals and random phase approximation

    NASA Astrophysics Data System (ADS)

    Xiao, Bing

    The meta-GGA functionals and random phase approximation are tested for phase transitions and a strongly correlated transition metal oxide in this dissertation. One of the latest meta-GGA functionals is also employed to study the van der Waals bound system in surface science. Our main purpose is to reveal the performance of new exchange-correlation functionals on various properties and systems. We are also interested in seeking the possible relationship between the performance of a semilocal functional and its exchange enhancement factor. We have studied the structural phase transitions in crystalline Si (insulator to metal), SiO2 (insulator to insulator) and Zr (metal to metal) systems, as a test of exchange energy semilocal functionals on Jacob's ladder. Our results confirm the energy-geometry delimma of GGAs in three systems. The most sophisticated non-empirical meta-generalized gradient approximations (meta-GGAs) such as TPSS (Tao-Perdew-Staroveov-Scuseria) and revTPSS (revised TPSS) give better lattice constants than PBE, but the phase transition parameters (energy difference and transition pressure) are smaller and less realistic than those from the latter GGA. However, the recent functionals of meta-GGA made simple family (MGGA_MS) behave differently to those previous meta-GGAs, predicting larger and more realistic phase transition parameters. Meanwhile, MGGA_MS also delivers the equilibrium geometry of crystalline materials similar to previous non-empirical meta-GGAs. In contrast to semilocal functionals, the nonlocal functionals such as the range-separated hybrid functional HSE06 (Heyd-Scuseria-Ernzerhof) and non-self consistent random phase approximation (RPA) are not only able to give the accurate equilibrium geometry , but also predict the realistic phase transition parameters for Si and SiO2 systems. The ground state of rutile-type vanadium dioxide (R-VO2) represents a great challenge to the current density functional theory. In this dissertation, we

  18. Non-equilibrium Phase Transitions: Activated Random Walks at Criticality

    NASA Astrophysics Data System (ADS)

    Cabezas, M.; Rolla, L. T.; Sidoravicius, V.

    2014-06-01

    In this paper we present rigorous results on the critical behavior of the Activated Random Walk model. We conjecture that on a general class of graphs, including , and under general initial conditions, the system at the critical point does not reach an absorbing state. We prove this for the case where the sleep rate is infinite. Moreover, for the one-dimensional asymmetric system, we identify the scaling limit of the flow through the origin at criticality. The case remains largely open, with the exception of the one-dimensional totally-asymmetric case, for which it is known that there is no fixation at criticality.

  19. Optical Security Card by Three-dimensional Random Phase Distribution

    NASA Astrophysics Data System (ADS)

    Matoba, Osamu; Nitta, Kouichi

    2007-10-01

    An optical security card based on a three-dimensional (3D) phase object is presented. This card enables us to develop a personal authentification system and secure data storage in a highly scattering medium. The authentification is implemented by the correlation between a speckle pattern of the 3D phase object and stored speckle patterns. For secure data storage, absorption distribution is involved in a scattering volume medium. Appropriate user can only reconstruct the absorption distribution by solving inverse problem. Experimental and numerical results are presented to show the effectiveness of the proposed system.

  20. Experimental demonstration of an active phase randomization and monitor module for quantum key distribution

    NASA Astrophysics Data System (ADS)

    Sun, Shi-Hai; Liang, Lin-Mei

    2012-08-01

    Phase randomization is a very important assumption in the BB84 quantum key distribution (QKD) system with weak coherent source; otherwise, eavesdropper may spy the final key. In this Letter, a stable and monitored active phase randomization scheme for the one-way and two-way QKD system is proposed and demonstrated in experiments. Furthermore, our scheme gives an easy way for Alice to monitor the degree of randomization in experiments. Therefore, we expect our scheme to become a standard part in future QKD systems due to its secure significance and feasibility.

  1. Flow measurement by cardiovascular magnetic resonance: a multi-centre multi-vendor study of background phase offset errors that can compromise the accuracy of derived regurgitant or shunt flow measurements

    PubMed Central

    2010-01-01

    Aims Cardiovascular magnetic resonance (CMR) allows non-invasive phase contrast measurements of flow through planes transecting large vessels. However, some clinically valuable applications are highly sensitive to errors caused by small offsets of measured velocities if these are not adequately corrected, for example by the use of static tissue or static phantom correction of the offset error. We studied the severity of uncorrected velocity offset errors across sites and CMR systems. Methods and Results In a multi-centre, multi-vendor study, breath-hold through-plane retrospectively ECG-gated phase contrast acquisitions, as are used clinically for aortic and pulmonary flow measurement, were applied to static gelatin phantoms in twelve 1.5 T CMR systems, using a velocity encoding range of 150 cm/s. No post-processing corrections of offsets were implemented. The greatest uncorrected velocity offset, taken as an average over a 'great vessel' region (30 mm diameter) located up to 70 mm in-plane distance from the magnet isocenter, ranged from 0.4 cm/s to 4.9 cm/s. It averaged 2.7 cm/s over all the planes and systems. By theoretical calculation, a velocity offset error of 0.6 cm/s (representing just 0.4% of a 150 cm/s velocity encoding range) is barely acceptable, potentially causing about 5% miscalculation of cardiac output and up to 10% error in shunt measurement. Conclusion In the absence of hardware or software upgrades able to reduce phase offset errors, all the systems tested appeared to require post-acquisition correction to achieve consistently reliable breath-hold measurements of flow. The effectiveness of offset correction software will still need testing with respect to clinical flow acquisitions. PMID:20074359

  2. Coherent-phase or random-phase acceleration of electron beams in solar flares

    NASA Technical Reports Server (NTRS)

    Aschwanden, Markus J.; Benz, Arnold O.; Montello, Maria L.

    1994-01-01

    Time structures of electron beam signatures at radio wavelengths are investigated to probe correlated versus random behavior in solar flares. In particular we address the issue whether acceleration and injection of electron beams is coherently modulated by a single source, or whether the injection is driven by a stochastic (possibly spatially fragmented) process. We analyze a total of approximately = 6000 type III bursts observed by Ikarus (Zurich) in the frequency range of 100-500 MHz, during 359 solar flares with simultaneous greater than or = 25 keV hard X-ray emission, in the years 1890-1983. In 155 flares we find a total of 260 continuous type III groups, with an average number of 13 +/- 9 bursts per group, a mean duration of D = 12 +/- 14 s, a mean period of P = 2.0 +/- 1.2 s, with the highest burst rate at a frequency of nu = 310 +/- 120 MHz. Pulse periods have been measured between 0.5 and 10 s, and can be described by an exponential distribution, i.e., N(P) varies as e (exp -P/1.0s). The period shows a frequency dependence of P(nu)=46(exp-0.6)(sub MHz)s for different flares, but is invariant during a particular flare. We measure the mean period P and its standard deviation sigma (sub p) in each type III group, and quantify the degree of periodicity (or phase-coherence) by the dimensionless parameter sigma (sub p)P. The representative sample of 260 type III burst groups shows a mean periodicity of sigma (sub p/P) = 0.37 +/- 0.12, while Monte Carlo simulations of an equivalent set of truly random time series show a distinctly different value of sigma (sub p)P = 0.93 +/- 0.26. This result indicates that the injection of electron beams is coherently modulated by a particle acceleration source which is either compact or has a global organization on a timescale of seconds, in contrast to an incoherent acceleration source, which is stochastic either in time or space. We discuss the constraints on the size of the acceleration region resulting from electron beam

  3. Effect of denosumab on Japanese patients with rheumatoid arthritis: a dose–response study of AMG 162 (Denosumab) in patients with RheumatoId arthritis on methotrexate to Validate inhibitory effect on bone Erosion (DRIVE)—a 12-month, multicentre, randomised, double-blind, placebo-controlled, phase II clinical trial

    PubMed Central

    Takeuchi, Tsutomu; Tanaka, Yoshiya; Ishiguro, Naoki; Yamanaka, Hisashi; Yoneda, Toshiyuki; Ohira, Takeshi; Okubo, Naoki; Genant, Harry K

    2016-01-01

    Objectives To evaluate efficacy and safety of three different regimens of denosumab, a fully human monoclonal antibody to receptor activator of nuclear factor kappa B (RANK) ligand (RANKL), for Japanese patients with rheumatoid arthritis (RA). Methods In this multicentre, randomised, placebo-controlled phase II study, 350 Japanese patients with RA between 6 months and <5 years, stratified by glucocorticoid use and rheumatoid factor status, were randomly assigned to subcutaneous injections of placebo or denosumab 60 mg every 6 months (Q6M), every 3 months (Q3M) or every 2 months (Q2M). All patients basically continued methotrexate treatment and had a supplement of calcium and vitamin D throughout the study. The primary endpoint was change in the modified Sharp erosion score from baseline to 12 months. Results Denosumab significantly inhibited the progression of bone erosion at 12 months compared with the placebo, and the mean changes of the modified Sharp erosion score at 12 months from baseline were 0.99, 0.27 (compared with placebo, p=0.0082), 0.14 (p=0.0036) and 0.09 (p<0.0001) in the placebo, Q6M, Q3M and Q2M, respectively. Secondary endpoint analysis revealed that denosumab also significantly inhibited the increase of the modified total Sharp score compared with the placebo, with no obvious evidence of an effect on joint space narrowing for denosumab. As shown in previous studies, denosumab increased bone mineral density. No apparent difference was observed in the safety profiles of denosumab and placebo. Conclusions Addition of denosumab to methotrexate has potential as a new therapeutic option for patients with RA with risk factors of joint destruction. Trial registration number JapicCTI-101263. PMID:26585988

  4. Use of drug therapy in the management of symptomatic ureteric stones in hospitalized adults (SUSPEND), a multicentre, placebo-controlled, randomized trial of a calcium-channel blocker (nifedipine) and an α-blocker (tamsulosin): study protocol for a randomized controlled trial

    PubMed Central

    2014-01-01

    Background Urinary stone disease is common, with an estimated prevalence among the general population of 2% to 3%. Ureteric stones can cause severe pain and have a significant impact on quality of life, accounting for over 15,000 hospital admissions in England annually. Uncomplicated cases of smaller stones in the lower ureter are traditionally treated expectantly. Those who fail standard care or develop complications undergo active treatment, such as extracorporeal shock wave lithotripsy or ureteroscopy with stone retrieval. Such interventions are expensive, require urological expertise and carry a risk of complications. Growing understanding of ureteric function and pathophysiology has led to the hypothesis that drugs causing relaxation of ureteric smooth muscle, such as the selective α-blocker tamsulosin and the calcium-channel blocker nifedipine, can enhance the spontaneous passage of ureteric stones. The use of drugs in augmenting stone passage, reducing the morbidity and costs associated with ureteric stone disease, is promising. However, the majority of clinical trials conducted to date have been small, poor to moderate quality and lacking in comprehensive economic evaluation. This trial aims to determine the clinical and cost-effectiveness of tamsulosin and nifedipine in the management of symptomatic urinary stones. Methods/design The SUSPEND (Spontaneous Urinary Stone Passage ENabled by Drugs) trial is a multicentre, double-blind, randomized controlled trial evaluating two medical expulsive therapy strategies (nifedipine or tamsulosin) versus placebo. Patients aged 18 to 65 with a ureteric stone confirmed by non-contrast computed tomography of the kidney, ureter and bladder will be randomized to receive nifedipine, tamsulosin or placebo (400 participants per arm) for a maximum of 28 days. The primary clinical outcome is spontaneous passage of ureteric stones at 4 weeks (defined as no further intervention required to facilitate stone passage). The

  5. Efficacy and safety of epratuzumab in patients with moderate/severe active systemic lupus erythematosus: results from EMBLEM, a phase IIb, randomised, double-blind, placebo-controlled, multicentre study

    PubMed Central

    Wallace, Daniel J; Kalunian, Kenneth; Petri, Michelle A; Strand, Vibeke; Houssiau, Frederic A; Pike, Marilyn; Kilgallen, Brian; Bongardt, Sabine; Barry, Anna; Kelley, Lexy; Gordon, Caroline

    2014-01-01

    Objective To identify a suitable dosing regimen of the CD22-targeted monoclonal antibody epratuzumab in adults with moderately to severely active systemic lupus erythematosus (SLE). Methods A phase IIb, multicentre, randomised controlled study (NCT00624351) was conducted with 227 patients (37–39 per arm) receiving either: placebo, epratuzumab 200 mg cumulative dose (cd) (100 mg every other week (EOW)), 800 mg cd (400 mg EOW), 2400 mg cd (600 mg weekly), 2400 mg cd (1200 mg EOW), or 3600 mg cd (1800 mg EOW). The primary endpoint (not powered for significance) was the week 12 responder rate measured using a novel composite endpoint, the British Isles Lupus Assessment Group (BILAG)-based Combined Lupus Assessment (BICLA). Results Proportion of responders was higher in all epratuzumab groups than with placebo (overall treatment effect test p=0.148). Exploratory pairwise analysis demonstrated clinical improvement in patients receiving a cd of 2400 mg epratuzumab (OR for 600 mg weekly vs placebo: 3.2 (95% CI 1.1 to 8.8), nominal p=0.03; OR for 1200 mg EOW vs placebo: 2.6 (0.9 to 7.1), nominal p=0.07). Post-hoc comparison of all 2400 mg cd patients versus placebo found an overall treatment effect (OR=2.9 (1.2 to 7.1), nominal p=0.02). Incidence of adverse events (AEs), serious AEs and infusion reactions was similar between epratuzumab and placebo groups, without decreases in immunoglobulin levels and only partial reduction in B-cell levels. Conclusions Treatment with epratuzumab 2400 mg cd was well tolerated in patients with moderately to severely active SLE, and associated with improvements in disease activity. Phase III studies are ongoing. PMID:23313811

  6. Smeared quantum phase transition in the dissipative random quantum Ising model

    NASA Astrophysics Data System (ADS)

    Vojta, Thomas; Hoyos, José A.

    2010-01-01

    We investigate the quantum phase transition in the random transverse-field Ising model under the influence of Ohmic dissipation. To this end, we numerically implement a strong-disorder renormalization-group scheme. We find that Ohmic dissipation destroys the quantum critical point and the associated quantum Griffiths phase by smearing. Our results quantitatively confirm a recent theory [J.A. Hoyos, T. Vojta, Phys. Rev. Lett. 100 (2008) 240601] of smeared quantum phase transitions.

  7. Phase transitions in optimal search times: How random walkers should combine resetting and flight scales

    NASA Astrophysics Data System (ADS)

    Campos, Daniel; Méndez, Vicenç

    2015-12-01

    Recent works have explored the properties of Lévy flights with resetting in one-dimensional domains and have reported the existence of phase transitions in the phase space of parameters which minimizes the mean first passage time (MFPT) through the origin [L. Kusmierz et al., Phys. Rev. Lett. 113, 220602 (2014), 10.1103/PhysRevLett.113.220602]. Here, we show how actually an interesting dynamics, including also phase transitions for the minimization of the MFPT, can also be obtained without invoking the use of Lévy statistics but for the simpler case of random walks with exponentially distributed flights of constant speed. We explore this dynamics both in the case of finite and infinite domains, and for different implementations of the resetting mechanism to show that different ways to introduce resetting consistently lead to a quite similar dynamics. The use of exponential flights has the strong advantage that exact solutions can be obtained easily for the MFPT through the origin, so a complete analytical characterization of the system dynamics can be provided. Furthermore, we discuss in detail how the phase transitions observed in random walks with resetting are closely related to several ideas recurrently used in the field of random search theory, in particular, to other mechanisms proposed to understand random search in space as mortal random walks or multiscale random walks. As a whole, we corroborate that one of the essential ingredients behind MFPT minimization lies in the combination of multiple movement scales (regardless of their specific origin).

  8. Masking property of quantum random cipher with phase mask encryption

    NASA Astrophysics Data System (ADS)

    Sohma, Masaki; Hirota, Osamu

    2014-10-01

    The security analysis of physical encryption protocol based on coherent pulse position modulation (CPPM) originated by Yuen is one of the most interesting topics in the study of cryptosystem with a security level beyond the Shannon limit. Although the implementation of CPPM scheme has certain difficulty, several methods have been proposed recently. This paper deals with the CPPM encryption in terms of symplectic transformation, which includes a phase mask encryption as a special example, and formulates a unified security analysis for such encryption schemes. Specifically, we give a lower bound of Eve's symbol error probability using reliability function theory to ensure that our proposed system exceeds the Shannon limit. Then we assume the secret key is given to Eve after her heterodyne measurement. Since this assumption means that Eve has a great advantage in the sense of the conventional cryptography, the lower bound of her error indeed ensures the security level beyond the Shannon limit. In addition, we show some numerical examples of the security performance.

  9. All-optical quantum random bit generation from intrinsically binary phase of parametric oscillators.

    PubMed

    Marandi, Alireza; Leindecker, Nick C; Vodopyanov, Konstantin L; Byer, Robert L

    2012-08-13

    We demonstrate a novel all-optical quantum random number generator (RNG) based on above-threshold binary phase state selection in a degenerate optical parametric oscillator (OPO). Photodetection is not a part of the random process, and no post processing is required for the generated bit sequence. We show that the outcome is statistically random with 99% confidence, and verify that the randomness is due to the phase of initiating photons generated through spontaneous parametric down conversion of the pump, with negligible contribution of classical noise sources. With the use of micro- and nanoscale OPO resonators, this technique offers a promise for simple, robust, and high-speed on-chip all-optical quantum RNGs. PMID:23038574

  10. Security authentication with a three-dimensional optical phase code using random forest classifier.

    PubMed

    Markman, Adam; Carnicer, Artur; Javidi, Bahram

    2016-06-01

    An object with a unique three-dimensional (3D) optical phase mask attached is analyzed for security and authentication. These 3D optical phase masks are more difficult to duplicate or to have a mathematical formulation compared with 2D masks and thus have improved security capabilities. A quick response code was modulated using a random 3D optical phase mask generating a 3D optical phase code (OPC). Due to the scattering of light through the 3D OPC, a unique speckle pattern based on the materials and structure in the 3D optical phase mask is generated and recorded on a CCD device. Feature extraction is performed by calculating the mean, variance, skewness, kurtosis, and entropy for each recorded speckle pattern. The random forest classifier is used for authentication. Optical experiments demonstrate the feasibility of the authentication scheme. PMID:27409445

  11. Multiple-wavelength double random phase encoding with CCD-plane sparse-phase multiplexing for optical information verification.

    PubMed

    Chen, Wen

    2015-12-20

    A novel method is proposed by using multiple-wavelength double random phase encoding (MW-DRPE) with CCD-plane sparse-phase multiplexing for optical information verification. Two different strategies are applied to conduct sparse-phase multiplexing in the CCD plane. The results demonstrate that large capacity can be achieved for optical multiple-image verification. The proposed optical verification strategy is implemented based on optical encoding, and the keys generated by optical encryption can further guarantee the safety of the designed optical multiple-image verification system. The proposed method provides a novel alternative for DRPE-based optical information verification. PMID:26837040

  12. Simultaneous transmission for an encrypted image and a double random-phase encryption key

    NASA Astrophysics Data System (ADS)

    Yuan, Sheng; Zhou, Xin; Li, Da-Hai; Zhou, Ding-Fu

    2007-06-01

    We propose a method to simultaneously transmit double random-phase encryption key and an encrypted image by making use of the fact that an acceptable decryption result can be obtained when only partial data of the encrypted image have been taken in the decryption process. First, the original image data are encoded as an encrypted image by a double random-phase encryption technique. Second, a double random-phase encryption key is encoded as an encoded key by the Rivest-Shamir-Adelman (RSA) public-key encryption algorithm. Then the amplitude of the encrypted image is modulated by the encoded key to form what we call an encoded image. Finally, the encoded image that carries both the encrypted image and the encoded key is delivered to the receiver. Based on such a method, the receiver can have an acceptable result and secure transmission can be guaranteed by the RSA cipher system.

  13. Universal polarization terahertz phase controllers using randomly aligned liquid crystal cells with graphene electrodes.

    PubMed

    Sasaki, Tomoyuki; Noda, Kohei; Kawatsuki, Nobuhiro; Ono, Hiroshi

    2015-04-01

    We present a universal polarization terahertz (THz) phase controller using a randomly aligned liquid crystal (LC) cell with graphene electrodes. The LC cell was fabricated using a nematic LC and two quartz substrates that were coated with a monolayer of graphene as the transparent electrode. The LC in the cell was prepared without any alignment treatments and was randomly aligned. The size of the random domains and the width of the disclination lines in the LC layer were several tens of microns. These textures disappeared when an alternating voltage was applied to the LC through the graphene layers. Using a THz time domain spectroscopic technique, we investigated the complex transmittance of the LC cell. The LC cell was highly transparent in the THz frequency range, and there was little change in the transmittance with the applied voltage. This indicated that the scattering loss originating in the randomly aligned LC molecules was small for the THz waves. We also demonstrated that the THz phase shift could be controlled by the applied voltage. The amplitude of the phase shift was explained by the ordinary and extraordinary refractive indices of the LC. These LC cells with graphene electrodes can be used to realize universal polarization THz phase controllers because of the random alignment. PMID:25831380

  14. Study protocol for a phase III multicentre, randomised, open-label, blinded-end point trial to evaluate the efficacy and safety of immunoglobulin plus cyclosporin A in patients with severe Kawasaki disease (KAICA Trial)

    PubMed Central

    Aoyagi, Reiko; Hamada, Hiromichi; Sato, Yasunori; Suzuki, Hiroyuki; Onouchi, Yoshihiro; Ebata, Ryota; Terauchi, Moe; Terai, Masaru; Hanaoka, Hideki; Hata, Akira

    2015-01-01

    Introduction Kawasaki disease (KD) is an acute, self-limited vasculitis of unknown aetiology that predominantly affects infants and young children. We hypothesise that cyclosporin A (CsA) may be effective in treating KD by regulating the Ca2+/NFAT signalling pathway. This trial compares the current standard therapy of intravenous immunoglobulin (IVIG) and the combined IVIG+CsA therapy in paediatric patients with severe KD. Methods and analysis This trial is a phase III, multicentre, randomised, open-label, blinded-end point trial that evaluates the efficacy and safety of IVIG+CsA therapy. Patients with severe KD who satisfy the eligibility criteria are randomised (1:1) to receive either CsA (5 mg/kg/day for 5 days; Neoral) plus high-dose IVIG (2 g/kg for 24 h and aspirin 30 mg/kg/day), or high-dose IVIG alone (2 g/kg for 24 h and aspirin 30 mg/kg/day). The primary end point is the frequency of occurrence of coronary artery abnormalities during the trial period. An independent end point review committee will be in charge of the trial assessment. Ethics and dissemination The protocol was approved by the Institutional Review Board of each institution. The trial was notified and registered at the Pharmaceutical and Medical Devices Agency, in Japan. The trial is currently on-going and is scheduled to finish in April 2017. The findings will be disseminated through peer-reviewed publications and conference presentations. Trial registration number JMA-IIA00174; Pre-results. PMID:26628527

  15. Single-shot phase imaging with randomized light (SPIRaL).

    PubMed

    Horisaki, Ryoichi; Egami, Riki; Tanida, Jun

    2016-02-22

    We present a method for single-shot phase imaging with randomized light (SPIRaL). In SPIRaL, the complex (amplitude and phase) field of an object illuminated with a randomized coherent beam is captured with an image sensor, without the need for any reference light. The object field is retrieved from the single captured intensity image by a compressive sensing-based algorithm with a sparsity constraint. SPIRaL has higher observation speed, light efficiency, and flexibility of the implementation compared with previous methods. We demonstrate SPIRaL numerically and experimentally. PMID:26907032

  16. Random exchange interaction effects on the phase transitions in frustrated classical Heisenberg model

    SciTech Connect

    Li, W. C.; Song, X.; Feng, J. J.; Zeng, M.; Gao, X. S.; Qin, M. H.; Jia, X. T.

    2015-07-07

    In this work, the effects of the random exchange interaction on the phase transitions and phase diagrams of classical frustrated Heisenberg model are investigated by Monte Carlo simulation in order to simulate the chemical doping effect in real materials. It is observed that the antiferromagnetic transitions shift toward low temperature with the increasing magnitude of the random exchange interaction, which can be qualitatively understood from the competitions among local spin states. This study is related to the magnetic properties in the doped iron-based superconductors.

  17. The generation of 68 Gbps quantum random number by measuring laser phase fluctuations.

    PubMed

    Nie, You-Qi; Huang, Leilei; Liu, Yang; Payne, Frank; Zhang, Jun; Pan, Jian-Wei

    2015-06-01

    The speed of a quantum random number generator is essential for practical applications, such as high-speed quantum key distribution systems. Here, we push the speed of a quantum random number generator to 68 Gbps by operating a laser around its threshold level. To achieve the rate, not only high-speed photodetector and high sampling rate are needed but also a very stable interferometer is required. A practical interferometer with active feedback instead of common temperature control is developed to meet the requirement of stability. Phase fluctuations of the laser are measured by the interferometer with a photodetector and then digitalized to raw random numbers with a rate of 80 Gbps. The min-entropy of the raw data is evaluated by modeling the system and is used to quantify the quantum randomness of the raw data. The bias of the raw data caused by other signals, such as classical and detection noises, can be removed by Toeplitz-matrix hashing randomness extraction. The final random numbers can pass through the standard randomness tests. Our demonstration shows that high-speed quantum random number generators are ready for practical usage. PMID:26133826

  18. The generation of 68 Gbps quantum random number by measuring laser phase fluctuations

    SciTech Connect

    Nie, You-Qi; Liu, Yang; Zhang, Jun Pan, Jian-Wei; Huang, Leilei; Payne, Frank

    2015-06-15

    The speed of a quantum random number generator is essential for practical applications, such as high-speed quantum key distribution systems. Here, we push the speed of a quantum random number generator to 68 Gbps by operating a laser around its threshold level. To achieve the rate, not only high-speed photodetector and high sampling rate are needed but also a very stable interferometer is required. A practical interferometer with active feedback instead of common temperature control is developed to meet the requirement of stability. Phase fluctuations of the laser are measured by the interferometer with a photodetector and then digitalized to raw random numbers with a rate of 80 Gbps. The min-entropy of the raw data is evaluated by modeling the system and is used to quantify the quantum randomness of the raw data. The bias of the raw data caused by other signals, such as classical and detection noises, can be removed by Toeplitz-matrix hashing randomness extraction. The final random numbers can pass through the standard randomness tests. Our demonstration shows that high-speed quantum random number generators are ready for practical usage.

  19. Lithium in patients with amyotrophic lateral sclerosis (LiCALS): a phase 3 multicentre, randomised, double-blind, placebo-controlled trial

    PubMed Central

    2013-01-01

    Summary Background Lithium has neuroprotective effects in cell and animal models of amyotrophic lateral sclerosis (ALS), and a small pilot study in patients with ALS showed a significant effect of lithium on survival. We aimed to assess whether lithium improves survival in patients with ALS. Methods The lithium carbonate in amyotrophic lateral sclerosis (LiCALS) trial is a randomised, double-blind, placebo-controlled trial of oral lithium taken daily for 18 months in patients with ALS. Patients aged at least 18 years who had ALS according to the revised El Escorial criteria, had disease duration between 6 and 36 months, and were taking riluzole were recruited from ten centres in the UK. Patients were randomly assigned (1:1) to receive either lithium or matched placebo tablets. Randomisation was via an online system done at the level of the individual by block randomisation with randomly varying block sizes, stratified by study centre and site of disease onset (limb or bulbar). All patients and assessing study personnel were masked to treatment assignment. The primary endpoint was the rate of survival at 18 months and was analysed by intention to treat. This study is registered with Eudract, number 2008-006891-31. Findings Between May 26, 2009, and Nov 10, 2011, 243 patients were screened, 214 of whom were randomly assigned to receive lithium (107 patients) or placebo (107 patients). Two patients discontinued treatment and one died before the target therapeutic lithium concentration could be achieved. 63 (59%) of 107 patients in the placebo group and 54 (50%) of 107 patients in the lithium group were alive at 18 months. The survival functions did not differ significantly between groups (Mantel-Cox log-rank χ2 on 1 df=1·64; p=0·20). After adjusting for study centre and site of onset using logistic regression, the relative odds of survival at 18 months (lithium vs placebo) was 0·71 (95% CI 0·40–1·24). 56 patients in the placebo group and 61 in the lithium

  20. Phase Separation Kinetics of a Binary Polymer Blend with Added Random Copolymer

    NASA Astrophysics Data System (ADS)

    Waldow, Dean; Barham, Bethany; Halasa, Adel

    1998-03-01

    The phase separation kinetics of a polymer blend with increasing amounts of random copolymer was studied using wide angle light scattering. The system is a blend of polystyrene and polybutadiene, and the copolymer is an asymmetric random styrene-butadiene copolymer (80/20). The composition of the blend is near critical and the weight percentages of the added copolymer vary from 0.0 to 2.5 percent. The temperature of the cloud point increases with increasing copolymer amount indicating a destabilizing effect. Light scattering data was collected while temperature was jumped from the one-phase region into the two-phase region near the phase boundary. Early stage and intermediate stage kinetics were analyzed using Cahn-Hillard-Cook theory and scaling theory. The early stage kinetics indicate a slowing of the diffusion constants with added copolymer, and the intermediate stage kinetics suggest that the scaling theory doesn't accurately describe the data.

  1. Optical information authentication using compressed double-random-phase-encoded images and quick-response codes.

    PubMed

    Wang, Xiaogang; Chen, Wen; Chen, Xudong

    2015-03-01

    In this paper, we develop a new optical information authentication system based on compressed double-random-phase-encoded images and quick-response (QR) codes, where the parameters of optical lightwave are used as keys for optical decryption and the QR code is a key for verification. An input image attached with QR code is first optically encoded in a simplified double random phase encoding (DRPE) scheme without using interferometric setup. From the single encoded intensity pattern recorded by a CCD camera, a compressed double-random-phase-encoded image, i.e., the sparse phase distribution used for optical decryption, is generated by using an iterative phase retrieval technique with QR code. We compare this technique to the other two methods proposed in literature, i.e., Fresnel domain information authentication based on the classical DRPE with holographic technique and information authentication based on DRPE and phase retrieval algorithm. Simulation results show that QR codes are effective on improving the security and data sparsity of optical information encryption and authentication system. PMID:25836845

  2. Deterministic matrices matching the compressed sensing phase transitions of Gaussian random matrices

    PubMed Central

    Monajemi, Hatef; Jafarpour, Sina; Gavish, Matan; Donoho, David L.; Ambikasaran, Sivaram; Bacallado, Sergio; Bharadia, Dinesh; Chen, Yuxin; Choi, Young; Chowdhury, Mainak; Chowdhury, Soham; Damle, Anil; Fithian, Will; Goetz, Georges; Grosenick, Logan; Gross, Sam; Hills, Gage; Hornstein, Michael; Lakkam, Milinda; Lee, Jason; Li, Jian; Liu, Linxi; Sing-Long, Carlos; Marx, Mike; Mittal, Akshay; Monajemi, Hatef; No, Albert; Omrani, Reza; Pekelis, Leonid; Qin, Junjie; Raines, Kevin; Ryu, Ernest; Saxe, Andrew; Shi, Dai; Siilats, Keith; Strauss, David; Tang, Gary; Wang, Chaojun; Zhou, Zoey; Zhu, Zhen

    2013-01-01

    In compressed sensing, one takes samples of an N-dimensional vector using an matrix A, obtaining undersampled measurements . For random matrices with independent standard Gaussian entries, it is known that, when is k-sparse, there is a precisely determined phase transition: for a certain region in the (,)-phase diagram, convex optimization typically finds the sparsest solution, whereas outside that region, it typically fails. It has been shown empirically that the same property—with the same phase transition location—holds for a wide range of non-Gaussian random matrix ensembles. We report extensive experiments showing that the Gaussian phase transition also describes numerous deterministic matrices, including Spikes and Sines, Spikes and Noiselets, Paley Frames, Delsarte-Goethals Frames, Chirp Sensing Matrices, and Grassmannian Frames. Namely, for each of these deterministic matrices in turn, for a typical k-sparse object, we observe that convex optimization is successful over a region of the phase diagram that coincides with the region known for Gaussian random matrices. Our experiments considered coefficients constrained to for four different sets , and the results establish our finding for each of the four associated phase transitions. PMID:23277588

  3. Single-random phase encoding architecture using a focus tunable lens

    NASA Astrophysics Data System (ADS)

    Mosso, E. F.; Bolognini, N.; Pérez, D. G.

    2016-02-01

    We propose a new nonlinear optical architecture based on a focus tunable lens and an iterative phase retrieval algorithm. It constitutes a compact encryption system that uses a single-random phase key to simultaneously encrypt (decrypt) amplitude and phase data. Summarily, the information encoded in a transmittance object (phase and amplitude) is randomly modulated by a diffuser when a laser beam illuminates it; once the beam reaches a focus tunable lens, different subjective speckle distributions are registered at some image plane as the focal length is tuned to different values. This set of speckle patterns constitutes a delocalized ciphertext, which is used in an iterative phase retrieval algorithm to reconstruct a complex ciphertext. The original data are decrypted propagating this ciphertext through a virtual optical system. In this system, amplitude data are straightforwardly decrypted while phase data can only be restored if the random modulation produced in the encryption process is compensated. Thus, an encryption-decryption process and authentication protocol can simultaneously be performed. We validate the feasibility of our proposal with simulated and experimental results.

  4. Security enhanced optical encryption system by random phase key and permutation key.

    PubMed

    He, Mingzhao; Tan, Qiaofeng; Cao, Liangcai; He, Qingsheng; Jin, Guofan

    2009-12-01

    Conventional double random phase encoding (DRPE) encrypts plaintext to white noise-like ciphertext which may attract attention of eavesdroppers, and recent research reported that DRPE is vulnerable to various attacks. Here we propose a security enhanced optical encryption system that can hide the existence of secret information by watermarking. The plaintext is encrypted using iterative fractional Fourier transform with random phase key, and ciphertext is randomly permuted with permutation key before watermarking. Cryptanalysis shows that linearity of the security system has been broken and the permutation key prevent the attacker from accessing the ciphertext in various attacks. A series of simulations have shown the effectiveness of this system and the security strength is enhanced for invisibility, nonlinearity and resistance against attacks. PMID:20052170

  5. Continuous and discontinuous absorbing-state phase transitions on Voronoi-Delaunay random lattices.

    PubMed

    de Oliveira, Marcelo M; Alves, Sidiney G; Ferreira, Silvio C

    2016-01-01

    We study absorbing-state phase transitions (APTs) in two-dimensional Voronoi-Delaunay (VD) random lattices with quenched coordination disorder. Quenched randomness usually changes the criticality and destroys discontinuous transitions in low-dimensional nonequilibrium systems. We performed extensive simulations of the Ziff-Gulari-Barshad model, and verified that the VD disorder does not change the nature of its discontinuous transition. Our results corroborate recent findings of Barghathi and Vojta [H. Barghathi and T. Vojta, Phys. Rev. Lett. 113, 120602 (2014)PRLTAO0031-900710.1103/PhysRevLett.113.120602], stating the irrelevance of topological disorder in a class of random lattices that includes VD, and raise the interesting possibility that disorder in nonequilibrium APT may, under certain conditions, be irrelevant for the phase coexistence. We also verify that the VD disorder is irrelevant for the critical behavior of models belonging to the directed percolation and Manna universality classes. PMID:26871027

  6. Continuous and discontinuous absorbing-state phase transitions on Voronoi-Delaunay random lattices

    NASA Astrophysics Data System (ADS)

    de Oliveira, Marcelo M.; Alves, Sidiney G.; Ferreira, Silvio C.

    2016-01-01

    We study absorbing-state phase transitions (APTs) in two-dimensional Voronoi-Delaunay (VD) random lattices with quenched coordination disorder. Quenched randomness usually changes the criticality and destroys discontinuous transitions in low-dimensional nonequilibrium systems. We performed extensive simulations of the Ziff-Gulari-Barshad model, and verified that the VD disorder does not change the nature of its discontinuous transition. Our results corroborate recent findings of Barghathi and Vojta [H. Barghathi and T. Vojta, Phys. Rev. Lett. 113, 120602 (2014), 10.1103/PhysRevLett.113.120602], stating the irrelevance of topological disorder in a class of random lattices that includes VD, and raise the interesting possibility that disorder in nonequilibrium APT may, under certain conditions, be irrelevant for the phase coexistence. We also verify that the VD disorder is irrelevant for the critical behavior of models belonging to the directed percolation and Manna universality classes.

  7. Phase Transitions for the Cavity Approach to the Clique Problem on Random Graphs

    NASA Astrophysics Data System (ADS)

    Gaudillière, Alexandre; Scoppola, Benedetto; Scoppola, Elisabetta; Viale, Massimiliano

    2011-12-01

    We give a rigorous proof of two phase transitions for a disordered statistical mechanics system used to define an algorithm to find large cliques inside Erdös random graphs. Such a system is a conservative probabilistic cellular automaton inspired by the cavity method originally introduced in spin glass theory.

  8. Drugs, Women and Violence in the Americas: U.S. Quantitative Results of a Multi-Centric Pilot Project (Phase 2)

    PubMed Central

    González-Guarda, Rosa María; Peragallo, Nilda; Lynch, Ami; Nemes, Susanna

    2011-01-01

    Objectives To explore the collective and individual experiences that Latin American females in the U.S. have with substance abuse, violence and risky sexual behaviors. Methods This study was conducted in two phases from July 2006 to June 2007 in south Florida. This paper covers Phase 2. In Phase 2, questionnaires were provided to women to test whether there is a relationship between demographics, acculturation, depression, self-esteem and substance use/abuse; whether there is a relationship between demographics, acculturation, depression, self-esteem and violence exposure and victimization; whether there is a relationship between demographics, acculturation, depression, self-esteem, HIV knowledge and STD and HIV/AIDS risks among respondents; and whether there is a relationship between substance abuse, violence victimization and HIV/AIDS risks among respondents. Results Participants reported high rates of alcohol and drug abuse among their current or most recent partners. This is a major concern because partner alcohol use and drug use was related to partner physical, sexual and psychological abuse. Only two factors were associated with lifetime drug use: income and acculturation. Over half of the participants reported being victims of at least one form of abuse during childhood and adulthood. A substantial component of abuse reported during adulthood was perpetrated by a currently or recent intimate partner. Conclusions The results from this study suggest that substance abuse, violence and HIV should be addressed in an integrative and comprehensive manner. Recommendations for the development of policies, programs and services addressing substance abuse, violence and risk for HIV among Latinos are provided. PMID:22504304

  9. Parametric down-conversion with nonideal and random quasi-phase-matching

    NASA Astrophysics Data System (ADS)

    Yang, Chun-Yao; Lin, Chun; Liljestrand, Charlotte; Su, Wei-Min; Canalias, Carlota; Chuu, Chih-Sung

    2016-05-01

    Quasi-phase-matching (QPM) has enriched the capacity of parametric down-conversion (PDC) in generating biphotons for many fundamental tests and advanced applications. However, it is not clear how the nonidealities and randomness in the QPM grating of a parametric down-converter may affect the quantum properties of the biphotons. This paper intends to provide insights into the interplay between PDC and nonideal or random QPM structures. Using a periodically poled nonlinear crystal with short periodicity, we conduct experimental and theoretical studies of PDC subject to nonideal duty cycle and random errors in domain lengths. We report the observation of biphotons emerging through noncritical birefringent-phasematching, which is impossible to occur in PDC with an ideal QPM grating, and a biphoton spectrum determined by the details of nonidealities and randomness. We also observed QPM biphotons with a diminished strength. These features are both confirmed by our theory. Our work provides new perspectives for biphoton engineering with QPM.

  10. Parametric down-conversion with nonideal and random quasi-phase-matching

    PubMed Central

    Yang, Chun-Yao; Lin, Chun; Liljestrand, Charlotte; Su, Wei-Min; Canalias, Carlota; Chuu, Chih-Sung

    2016-01-01

    Quasi-phase-matching (QPM) has enriched the capacity of parametric down-conversion (PDC) in generating biphotons for many fundamental tests and advanced applications. However, it is not clear how the nonidealities and randomness in the QPM grating of a parametric down-converter may affect the quantum properties of the biphotons. This paper intends to provide insights into the interplay between PDC and nonideal or random QPM structures. Using a periodically poled nonlinear crystal with short periodicity, we conduct experimental and theoretical studies of PDC subject to nonideal duty cycle and random errors in domain lengths. We report the observation of biphotons emerging through noncritical birefringent-phasematching, which is impossible to occur in PDC with an ideal QPM grating, and a biphoton spectrum determined by the details of nonidealities and randomness. We also observed QPM biphotons with a diminished strength. These features are both confirmed by our theory. Our work provides new perspectives for biphoton engineering with QPM. PMID:27173482

  11. Parametric down-conversion with nonideal and random quasi-phase-matching.

    PubMed

    Yang, Chun-Yao; Lin, Chun; Liljestrand, Charlotte; Su, Wei-Min; Canalias, Carlota; Chuu, Chih-Sung

    2016-01-01

    Quasi-phase-matching (QPM) has enriched the capacity of parametric down-conversion (PDC) in generating biphotons for many fundamental tests and advanced applications. However, it is not clear how the nonidealities and randomness in the QPM grating of a parametric down-converter may affect the quantum properties of the biphotons. This paper intends to provide insights into the interplay between PDC and nonideal or random QPM structures. Using a periodically poled nonlinear crystal with short periodicity, we conduct experimental and theoretical studies of PDC subject to nonideal duty cycle and random errors in domain lengths. We report the observation of biphotons emerging through noncritical birefringent-phasematching, which is impossible to occur in PDC with an ideal QPM grating, and a biphoton spectrum determined by the details of nonidealities and randomness. We also observed QPM biphotons with a diminished strength. These features are both confirmed by our theory. Our work provides new perspectives for biphoton engineering with QPM. PMID:27173482

  12. Phase 2 multicentre trial investigating intermittent and continuous dosing schedules of the poly(ADP-ribose) polymerase inhibitor rucaparib in germline BRCA mutation carriers with advanced ovarian and breast cancer

    PubMed Central

    Drew, Yvette; Ledermann, Jonathan; Hall, Geoff; Rea, Daniel; Glasspool, Ros; Highley, Martin; Jayson, Gordon; Sludden, Julieann; Murray, James; Jamieson, David; Halford, Sarah; Acton, Gary; Backholer, Zoe; Mangano, Raffaella; Boddy, Alan; Curtin, Nicola; Plummer, Ruth

    2016-01-01

    Background: Rucaparib is an orally available potent selective small-molecule inhibitor of poly(ADP-ribose) polymerase (PARP) 1 and 2. Rucaparib induces synthetic lethality in cancer cells defective in the homologous recombination repair pathway including BRCA-1/2. We investigated the efficacy and safety of single-agent rucaparib in germline (g) BRCA mutation carriers with advanced breast and ovarian cancers. Methods: Phase II, open-label, multicentre trial of rucaparib in proven BRCA-1/2 mutation carriers with advanced breast and or ovarian cancer, WHO PS 0–1 and normal organ function. Intravenous (i.v.) and subsequently oral rucaparib were assessed, using a range of dosing schedules, to determine the safety, tolerability, dose-limiting toxic effects and pharmacodynamic (PD) and pharmacokinetic (PK) profiles. Results: Rucaparib was well tolerated in patients up to doses of 480 mg per day and is a potent inhibitor of PARP, with sustained inhibition ⩾24 h after single doses. The i.v. rucaparib (intermittent dosing schedule) resulted in an objective response rate (ORR) of only 2% but with 41% (18 out of 44) patients achieved stable disease for ⩾12 weeks and 3 patients maintaining disease stabilisation for >52 weeks. The ORR for oral rucaparib (across all six dose levels) was 15%. In the oral cohorts, 81% (22 out of 27) of the patients had ovarian cancer and 12 out of 13, who were dosed continuously, achieved RECIST complete response/partial response (CR/PR) or stable disease (SD) ⩾12 weeks, with a median duration of response of 179 days (range 84–567 days). Conclusions: Rucaparib is well tolerated and results in high levels of PARP inhibition in surrogate tissues even at the lowest dose levels. Rucaparib is active in gBRCA-mutant ovarian cancer and this activity correlates with platinum-free interval. The key lessons learned from this study is that continuous rucaparib dosing is required for optimal response, the recommended phase 2 dose (RP2D) for

  13. Vulnerability to ciphertext-only attack of optical encryption scheme based on double random phase encoding.

    PubMed

    Liu, Xiaoli; Wu, Jiachen; He, Wenqi; Liao, Meihua; Zhang, Chenggong; Peng, Xiang

    2015-07-27

    We demonstrate in this paper that the traditional double random phase encoding (DRPE) technique is vulnerable to ciphertext-only attack (COA). In this method, an unauthorized user (or say attacker) is assumed to be able to retrieve the corresponding plaintext from the only ciphertext under some certain condition. The proposed scheme mainly relies on a hybrid iterative phase retrieval (HIPR) algorithm, which combines various phase retrieval algorithms. With an estimation of the number of nonzero pixels (NNP) in the original plaintext, an attacker could recover the plaintext in a large extent. The simulation results show that this method is feasible and validate. PMID:26367558

  14. Investigating the Sliding Phase in Strongly and Randomly Coupled Quasi-2D Bose Gasses

    NASA Astrophysics Data System (ADS)

    Reed, Matthew; Smith, Zack; Dewan, Aftaab; Rolston, Steve

    2014-05-01

    Asymptotic analytical [Mohan et al. 2010] functional RNG [Pekker et al. 2010] and Monte Carlo [Laflorencie 2012] methods identified an anomalous Griffiths phase in the 3D XY model in the presence of disorder. A stack of cold 2D Bose gasses with random nearest neighbor inter-planar couplings should pass through two phase transitions as one increases temperature, first from a 3D superfluid to a stack of 2D superfluids, and then to a thermal state. We discuss our investigation of this intermediate phase in a stack of strongly coupled quasi-2D Rb 87 pancakes generated by a truly disordered 1D optical potential.

  15. Poor response to azithromycin in cutaneous leishmaniasis leading to a premature interruption of a multicentric phase III clinical trial in Brazil.

    PubMed

    Toledo Junior, Antonio; Daher, André Bastos; Amaral, Thaís Alves; Carvalho, Sílvio Fernando Guimarães; Romero, Gustavo Adolfo Sierra; Rabello, Ana

    2014-01-01

    Introduction Parenteral antimony-based compounds are still the standard of care for cutaneous leishmaniasis (CL) treatment in many countries, despite their high toxicity. Previous studies showed that oral azithromycin could be an option for CL treatment. The aim of this study was to evaluate efficacy and safety of oral azithromycin (AZ) for CL treatment compared with injectable meglumine antimoniate (MA). Methods This was a randomized, open-label, 2-arm, non-inferiority clinical trial. Treatment-naïve patients with localized CL were treated with MA (15mg/kg/day up to 1,215mg) or AZ (500mg/day) during 20 consecutive days. The primary efficacy end point was a CL cure 90 days after treatment completion. The analysis was performed with intention-to-treat (ITT) and per protocol (PP) analyses. After an anticipated interim analysis, the study was interrupted due to the high failure rate in the azithromycin group. Results Twenty-four volunteers were included in each group. The MA group had a higher cure rate than the AZ group with the ITT and PP analyses, which were 54.2% versus 20.8% [relative risk (RR) 1.97; 95% confidence intervals (95%CI) 1.13-3.42] and 72.2% versus 23.8% (RR 3.03; 95%CI 1.34-6.87), respectively. No unexpected adverse events were observed. Conclusions Azithromycin is ineffective for CL treatment and does not seem to have a role in the therapeutic arsenal for CL. PMID:25626655

  16. Statistical methodology for the evaluation of vaccine efficacy in a phase III multi-centre trial of the RTS,S/AS01 malaria vaccine in African children

    PubMed Central

    2011-01-01

    Background There has been much debate about the appropriate statistical methodology for the evaluation of malaria field studies and the challenges in interpreting data arising from these trials. Methods The present paper describes, for a pivotal phase III efficacy of the RTS, S/AS01 malaria vaccine, the methods of the statistical analysis and the rationale for their selection. The methods used to estimate efficacy of the primary course of vaccination, and of a booster dose, in preventing clinical episodes of uncomplicated and severe malaria, and to determine the duration of protection, are described. The interpretation of various measures of efficacy in terms of the potential public health impact of the vaccine is discussed. Conclusions The methodology selected to analyse the clinical trial must be scientifically sound, acceptable to regulatory authorities and meaningful to those responsible for malaria control and public health policy. Trial registration Clinicaltrials.gov NCT00866619 PMID:21816030

  17. Hacking on decoy-state quantum key distribution system with partial phase randomization

    PubMed Central

    Sun, Shi-Hai; Jiang, Mu-Sheng; Ma, Xiang-Chun; Li, Chun-Yan; Liang, Lin-Mei

    2014-01-01

    Quantum key distribution (QKD) provides means for unconditional secure key transmission between two distant parties. However, in practical implementations, it suffers from quantum hacking due to device imperfections. Here we propose a hybrid measurement attack, with only linear optics, homodyne detection, and single photon detection, to the widely used vacuum + weak decoy state QKD system when the phase of source is partially randomized. Our analysis shows that, in some parameter regimes, the proposed attack would result in an entanglement breaking channel but still be able to trick the legitimate users to believe they have transmitted secure keys. That is, the eavesdropper is able to steal all the key information without discovered by the users. Thus, our proposal reveals that partial phase randomization is not sufficient to guarantee the security of phase-encoding QKD systems with weak coherent states. PMID:24755767

  18. Novel copyright information hiding method based on random phase matrix of Fresnel diffraction transforms

    NASA Astrophysics Data System (ADS)

    Cao, Chao; Chen, Ru-jun

    2009-10-01

    In this paper, we present a new copyright information hide method for digital images in Moiré fringe formats. The copyright information is embedded into the protected image and the detecting image based on Fresnel phase matrix. Firstly, using Fresnel diffraction transform, the random phase matrix of copyright information is generated. Then, according to Moiré fringe principle, the protected image and the detecting image are modulated respectively based on the random phase matrix, and the copyright information is embedded into them. When the protected image and the detecting image are overlapped, the copyright information can reappear. Experiment results show that our method has good concealment performance, and is a new way for copyright protection.

  19. Hacking on decoy-state quantum key distribution system with partial phase randomization

    NASA Astrophysics Data System (ADS)

    Sun, Shi-Hai; Jiang, Mu-Sheng; Ma, Xiang-Chun; Li, Chun-Yan; Liang, Lin-Mei

    2014-04-01

    Quantum key distribution (QKD) provides means for unconditional secure key transmission between two distant parties. However, in practical implementations, it suffers from quantum hacking due to device imperfections. Here we propose a hybrid measurement attack, with only linear optics, homodyne detection, and single photon detection, to the widely used vacuum + weak decoy state QKD system when the phase of source is partially randomized. Our analysis shows that, in some parameter regimes, the proposed attack would result in an entanglement breaking channel but still be able to trick the legitimate users to believe they have transmitted secure keys. That is, the eavesdropper is able to steal all the key information without discovered by the users. Thus, our proposal reveals that partial phase randomization is not sufficient to guarantee the security of phase-encoding QKD systems with weak coherent states.

  20. Double image encryption based on random phase encoding in the fractional Fourier domain.

    PubMed

    Tao, Ran; Xin, Yi; Wang, Yue

    2007-11-26

    A novel image encryption method is proposed by utilizing random phase encoding in the fractional Fourier domain to encrypt two images into one encrypted image with stationary white distribution. By applying the correct keys which consist of the fractional orders, the random phase masks and the pixel scrambling operator, the two primary images can be recovered without cross-talk. The decryption process is robust against the loss of data. The phase-based image with a larger key space is more sensitive to keys and disturbances than the amplitude-based image. The pixel scrambling operation improves the quality of the decrypted image when noise perturbation occurs. The novel approach is verified by simulations. PMID:19550895

  1. Hacking on decoy-state quantum key distribution system with partial phase randomization.

    PubMed

    Sun, Shi-Hai; Jiang, Mu-Sheng; Ma, Xiang-Chun; Li, Chun-Yan; Liang, Lin-Mei

    2014-01-01

    Quantum key distribution (QKD) provides means for unconditional secure key transmission between two distant parties. However, in practical implementations, it suffers from quantum hacking due to device imperfections. Here we propose a hybrid measurement attack, with only linear optics, homodyne detection, and single photon detection, to the widely used vacuum + weak decoy state QKD system when the phase of source is partially randomized. Our analysis shows that, in some parameter regimes, the proposed attack would result in an entanglement breaking channel but still be able to trick the legitimate users to believe they have transmitted secure keys. That is, the eavesdropper is able to steal all the key information without discovered by the users. Thus, our proposal reveals that partial phase randomization is not sufficient to guarantee the security of phase-encoding QKD systems with weak coherent states. PMID:24755767

  2. The effects of monomer sequence distribution and isotopic substitution on solution phase behavior of random copolymers

    NASA Astrophysics Data System (ADS)

    Genzer, Jan; Kuk Jhon, Young; Krishnamoorti, Ramanan

    2010-03-01

    We report on the effect of chemical composition, co-monomer distribution and ^1H/^2D isotopic substitution on the phase behavior in random copolymers of poly(styrene-co-4-bromostyrene) (PBrxS), where x denotes the mole fraction of 4-bromostyrene (4-BrS), in cyclohexane. By adjusting the solvent quality during bromination of parent polystyrene, either random or random blocky PBrxS, (r-PBrxS or b-PBrxS, respectively), were synthesized. We study the temperature dependence of phase behavior of PBrxS with various x in cyclohexane as a function of the polymer concentration using cloud point measurements and small-angle neutron scattering. Our results reveal that for a given 4-BrS content, the cloud points of b-PBrxS solutions are consistently higher and broader than those observed in r-PBrxS solutions. The transition temperature has also been found to depend on the isotope substitution of ^1H or ^2D in either the polymer or the solvent. Small angle neutron scattering measurements indicate significant differences in the temperature dependence of the thermodynamic behavior for the random and blocky samples and the nature of the fluctuations upon approaching the phase boundaries.

  3. Random-diluted triangular plaquette model: Study of phase transitions in a kinetically constrained model

    NASA Astrophysics Data System (ADS)

    Franz, Silvio; Gradenigo, Giacomo; Spigler, Stefano

    2016-03-01

    We study how the thermodynamic properties of the triangular plaquette model (TPM) are influenced by the addition of extra interactions. The thermodynamics of the original TPM is trivial, while its dynamics is glassy, as usual in kinetically constrained models. As soon as we generalize the model to include additional interactions, a thermodynamic phase transition appears in the system. The additional interactions we consider are either short ranged, forming a regular lattice in the plane, or long ranged of the small-world kind. In the case of long-range interactions we call the new model the random-diluted TPM. We provide arguments that the model so modified should undergo a thermodynamic phase transition, and that in the long-range case this is a glass transition of the "random first-order" kind. Finally, we give support to our conjectures studying the finite-temperature phase diagram of the random-diluted TPM in the Bethe approximation. This corresponds to the exact calculation on the random regular graph, where free energy and configurational entropy can be computed by means of the cavity equations.

  4. Random-diluted triangular plaquette model: Study of phase transitions in a kinetically constrained model.

    PubMed

    Franz, Silvio; Gradenigo, Giacomo; Spigler, Stefano

    2016-03-01

    We study how the thermodynamic properties of the triangular plaquette model (TPM) are influenced by the addition of extra interactions. The thermodynamics of the original TPM is trivial, while its dynamics is glassy, as usual in kinetically constrained models. As soon as we generalize the model to include additional interactions, a thermodynamic phase transition appears in the system. The additional interactions we consider are either short ranged, forming a regular lattice in the plane, or long ranged of the small-world kind. In the case of long-range interactions we call the new model the random-diluted TPM. We provide arguments that the model so modified should undergo a thermodynamic phase transition, and that in the long-range case this is a glass transition of the "random first-order" kind. Finally, we give support to our conjectures studying the finite-temperature phase diagram of the random-diluted TPM in the Bethe approximation. This corresponds to the exact calculation on the random regular graph, where free energy and configurational entropy can be computed by means of the cavity equations. PMID:27078408

  5. Spin-glass phase transitions and minimum energy of the random feedback vertex set problem.

    PubMed

    Qin, Shao-Meng; Zeng, Ying; Zhou, Hai-Jun

    2016-08-01

    A feedback vertex set (FVS) of an undirected graph contains vertices from every cycle of this graph. Constructing a FVS of sufficiently small cardinality is very difficult in the worst cases, but for random graphs this problem can be efficiently solved by converting it into an appropriate spin-glass model [H.-J. Zhou, Eur. Phys. J. B 86, 455 (2013)EPJBFY1434-602810.1140/epjb/e2013-40690-1]. In the present work we study the spin-glass phase transitions and the minimum energy density of the random FVS problem by the first-step replica-symmetry-breaking (1RSB) mean-field theory. For both regular random graphs and Erdös-Rényi graphs, we determine the inverse temperature β_{l} at which the replica-symmetric mean-field theory loses its local stability, the inverse temperature β_{d} of the dynamical (clustering) phase transition, and the inverse temperature β_{s} of the static (condensation) phase transition. These critical inverse temperatures all change with the mean vertex degree in a nonmonotonic way, and β_{d} is distinct from β_{s} for regular random graphs of vertex degrees K>60, while β_{d} are identical to β_{s} for Erdös-Rényi graphs at least up to mean vertex degree c=512. We then derive the zero-temperature limit of the 1RSB theory and use it to compute the minimum FVS cardinality. PMID:27627285

  6. A randomized phase 2a efficacy and safety trial of the topical Janus kinase inhibitor tofacitinib in the treatment of chronic plaque psoriasis

    PubMed Central

    Ports, WC; Khan, S; Lan, S; Lamba, M; Bolduc, C; Bissonnette, R; Papp, K

    2013-01-01

    Background Tofacitinib (CP-690,550) is a novel Janus kinase inhibitor in development as an oral formulation for the treatment of several inflammatory diseases including psoriasis. Objectives This phase 2a study aimed to assess the efficacy, systemic safety, local tolerability and systemic pharmacokinetics of topical tofacitinib in mild-to-moderate plaque psoriasis. Methods Two tofacitinib ointment formulations were evaluated in this multicentre, double-blind, vehicle-controlled trial (NCT01246583). Seventy-one patients were randomized 2 : 1 : 2 : 1 to 2% tofacitinib ointment 1, vehicle 1, 2% tofacitinib ointment 2 and vehicle 2, each administered twice daily for 4 weeks to a single fixed 300 cm2 treatment area containing a target plaque with or without one or more nontarget plaques and normal skin. Results The primary endpoint of percentage change from baseline in the Target Plaque Severity Score at week 4 demonstrated statistically significant improvement for ointment 1 [least squares mean (LSM) –54·4%] vs. vehicle 1 (LSM –41·5%), but not ointment 2 (LSM –24·2%) vs. vehicle 2 (LSM –17·2%). Secondary endpoints (target plaque area and Itch Severity Item) improved similarly for tofacitinib ointment vs. corresponding vehicle. Adverse event (AE) occurrence was similar across treatment groups. All AEs were mild or moderate and none were serious or led to subject discontinuation. One application-site AE (erythema) was reported. Tofacitinib mean systemic exposure was minimal and was greater for ointment 1 than for ointment 2. Conclusions Tofacitinib ointment 1 was well tolerated and efficacious compared with vehicle for the treatment of plaque psoriasis. Further study of topical tofacitinib for psoriasis treatment is warranted. PMID:23387374

  7. Dose-intensified chemotherapy alone or in combination with mogamulizumab in newly diagnosed aggressive adult T-cell leukaemia-lymphoma: a randomized phase II study.

    PubMed

    Ishida, Takashi; Jo, Tatsuro; Takemoto, Shigeki; Suzushima, Hitoshi; Uozumi, Kimiharu; Yamamoto, Kazuhito; Uike, Naokuni; Saburi, Yoshio; Nosaka, Kisato; Utsunomiya, Atae; Tobinai, Kensei; Fujiwara, Hiroshi; Ishitsuka, Kenji; Yoshida, Shinichiro; Taira, Naoya; Moriuchi, Yukiyoshi; Imada, Kazunori; Miyamoto, Toshihiro; Akinaga, Shiro; Tomonaga, Masao; Ueda, Ryuzo

    2015-06-01

    This multicentre, randomized, phase II study was conducted to examine whether the addition of mogamulizumab, a humanized anti-CC chemokine receptor 4 antibody, to mLSG15, a dose-intensified chemotherapy, further increases efficacy without compromising safety of patients with newly diagnosed aggressive adult T-cell leukaemia-lymphoma (ATL). Patients were assigned 1:1 to receive mLSG15 plus mogamulizumab or mLSG15 alone. The primary endpoint was the complete response rate (%CR); secondary endpoints included the overall response rate (ORR) and safety. The %CR and ORR in the mLSG15-plus-mogamulizumab arm (n = 29) were 52% [95% confidence interval (CI), 33-71%] and 86%, respectively; the corresponding values in the mLSG15 arm (n = 24) were 33% (95% CI, 16-55%) and 75%, respectively. Grade ≥ 3 treatment-emergent adverse events, including anaemia, thrombocytopenia, lymphopenia, leucopenia and decreased appetite, were observed more frequently (≥10% difference) in the mLSG15-plus-mogamulizumab arm. Several adverse events, including skin disorders, cytomegalovirus infection, pyrexia, hyperglycaemia and interstitial lung disease, were observed only in the mLSG15-plus-mogamulizumab arm. Although the combination strategy showed a potentially less favourable safety profile, a higher %CR was achieved, providing the basis for further investigation of this novel treatment for newly diagnosed aggressive ATL. This study was registered at ClinicalTrials.gov, identifier: NCT01173887. PMID:25733162

  8. Phase diagram of a three-dimensional antiferromagnet with random magnetic anisotropy.

    PubMed

    Perez, Felio A; Borisov, Pavel; Johnson, Trent A; Stanescu, Tudor D; Trappen, Robbyn; Holcomb, Mikel B; Lederman, David; Fitzsimmons, M R; Aczel, Adam A; Hong, Tao

    2015-03-01

    Three-dimensional antiferromagnets with random magnetic anisotropy (RMA) that have been experimentally studied to date have competing two-dimensional and three-dimensional exchange interactions which can obscure the authentic effects of RMA. The magnetic phase diagram of Fe_{x}Ni_{1-x}F_{2} epitaxial thin films with true random single-ion anisotropy was deduced from magnetometry and neutron scattering measurements and analyzed using mean-field theory. Regions with uniaxial, oblique, and easy-plane anisotropies were identified. A RMA-induced glass region was discovered where a Griffiths-like breakdown of long-range spin order occurs. PMID:25793845

  9. Phase Diagram of a Three-Dimensional Antiferromagnet with Random Magnetic Anisotropy

    SciTech Connect

    Perez, Felio A.; Borisov, Pavel; Johnson, Trent A.; Stanescu, Tudor D.; Trappen, Robbyn; Holcomb, Mikel B.; Lederman, David; Fitzsimmons, M. R.; Aczel, Adam A.; Hong, Tao

    2015-03-04

    Three-dimensional (3D) antiferromagnets with random magnetic anisotropy (RMA) that were experimentally studied to date have competing two-dimensional and three-dimensional exchange interactions which can obscure the authentic effects of RMA. The magnetic phase diagram of FexNi1-xF2 epitaxial thin films with true random single-ion anisotropy was deduced from magnetometry and neutron scattering measurements and analyzed using mean field theory. Regions with uniaxial, oblique and easy plane anisotropies were identified. A RMA-induced glass region was discovered where a Griffiths-like breakdown of long-range spin order occurs.

  10. Phase Diagram of a Three-Dimensional Antiferromagnet with Random Magnetic Anisotropy

    DOE PAGESBeta

    Perez, Felio A.; Borisov, Pavel; Johnson, Trent A.; Stanescu, Tudor D.; Trappen, Robbyn; Holcomb, Mikel B.; Lederman, David; Fitzsimmons, M. R.; Aczel, Adam A.; Hong, Tao

    2015-03-04

    Three-dimensional (3D) antiferromagnets with random magnetic anisotropy (RMA) that were experimentally studied to date have competing two-dimensional and three-dimensional exchange interactions which can obscure the authentic effects of RMA. The magnetic phase diagram of FexNi1-xF2 epitaxial thin films with true random single-ion anisotropy was deduced from magnetometry and neutron scattering measurements and analyzed using mean field theory. Regions with uniaxial, oblique and easy plane anisotropies were identified. A RMA-induced glass region was discovered where a Griffiths-like breakdown of long-range spin order occurs.

  11. Fluctuating pulse propagation in resonant nonlinear media: self-induced transparency random phase soliton formation.

    PubMed

    Mokhtarpour, Laleh; Ponomarenko, Sergey A

    2015-11-16

    We numerically investigate partially coherent short pulse propagation in nonlinear media near optical resonance. We examine how the pulse state of coherence at the source affects the evolution of the ensemble averaged intensity, mutual coherence function, and temporal degree of coherence of the pulse ensemble. We report evidence of self-induced transparency random phase soliton formation for the relatively coherent incident pulses with sufficiently large average areas. We also show that random pulses lose their coherence on propagation in resonant media and we explain this phenomenon in qualitative terms. PMID:26698507

  12. Phase II single arm open label multicentre clinical trial to evaluate the efficacy and side effects of a combination of gefitinib and methotrexate to treat tubal ectopic pregnancies (GEM II): study protocol

    PubMed Central

    Horne, Andrew W; Skubisz, Monika M; Doust, Ann; Duncan, W Colin; Wallace, Euan; Critchley, Hilary O D; Johns, Terrance G; Norman, Jane E; Bhattacharya, Siladitya; Mollison, Jill; Rassmusen, Michael; Tong, Stephen

    2013-01-01

    Introduction Tubal ectopic pregnancy (tEP) is the most common life-threatening condition in gynaecology. tEPs with pretreatment serum human chorionic gonadotrophin (hCG) levels <1000 IU/L respond well to outpatient medical treatment with intramuscular methotrexate (MTX). TEPs with hCG >1000 IU/L take a significant time to resolve with MTX and require multiple outpatient monitoring visits. Gefitinib is an orally active epidermal growth factor receptor (EGFR) antagonist. In preclinical studies, we found that EP implantation sites express high levels of EGFR and that gefitinib augments MTX-induced regression of pregnancy-like tissue. We performed a phase I toxicity study administering oral gefitinib and intramuscular MTX to 12 women with tEPs. The combination therapy did not cause significant toxicities and was well tolerated. We noted that combination therapy resolved the tEPs faster than MTX alone. We now describe the protocol of a larger single arm trial to estimate the efficacy and side effects of combination gefitinib and MTX to treat stable tEPs with hCG 1000–10 000 IU/L Methods and analysis We propose to undertake a single-arm multicentre open label trial (in Edinburgh and Melbourne) and recruit 28 women with tEPs (pretreatment serum hCG 1000–10 000 IU/L). We intend to give a single dose of intramuscular MTX (50 mg/m2) and oral gefitinib (250 mg) daily for 7 days. Our primary outcome is the resolution of EP to non-pregnant hCG levels <15 IU/L without requirement of surgery. Our secondary outcomes are comparison of time to resolution against historical controls given MTX only, and safety and tolerability as determined by clinical/biochemical assessment. Ethics and dissemination Ethical approval has been obtained from Scotland A Research Ethics Committee (MREC 11/AL/0350), Southern Health Human Research Ethics Committee B (HREC 11180B) and the Mercy Health Human Research Ethics Committee (R12/25). Data will be presented at international

  13. Efficacy and safety of regorafenib for advanced gastrointestinal stromal tumours after failure of imatinib and sunitinib: an international, multicentre, prospective, randomised, placebo-controlled phase 3 trial (GRID)

    PubMed Central

    Demetri, George D; Reichardt, Peter; Kang, Yoon-Koo; Blay, Jean-Yves; Rutkowski, Piotr; Gelderblom, Hans; Hohenberger, Peter; Leahy, Michael; von Mehren, Margaret; Joensuu, Heikki; Badalamenti, Giuseppe; Blackstein, Martin; Cesne, Axel Le; Schöffski, Patrick; Maki, Robert G; Bauer, Sebastian; Nguyen, Binh Bui; Xu, Jianming; Nishida, Toshirou; Chung, John; Kappeler, Christian; Kuss, Iris; Laurent, Dirk; Casali, Paolo

    2013-01-01

    Summary Background To date, only two agents, imatinib and sunitinib, have shown clinical benefit in patients with gastrointestinal stromal tumours (GISTs), but almost all metastatic GISTs eventually develop resistance to these agents, resulting in fatal disease progression. This phase 3 trial assessed efficacy and safety of regorafenib in patients with metastatic and/or unresectable GIST progressing after failure of at least imatinib and sunitinib. Methods Patients were randomised 2:1 to receive either regorafenib 160 mg orally daily or placebo, plus best supportive care in both arms, for the first 3 weeks of each 4-week cycle. The primary endpoint was progression-free survival (PFS). Upon disease progression, patients on placebo could cross over to regorafenib. Secondary endpoints included overall survival (OS), objective response rate, disease control rate (DCR: rate of durable stable disease lasting for ≥12 weeks plus complete or partial responses), and safety. This trial is registered at ClinicalTrials.gov (NCT01271712). Results From January to August 2011, 240 patients were screened at 57 centres in 17 countries, and 199 patients were randomised to receive regorafenib (n=133) or matching placebo (n=66). Median PFS per independent blinded central review was 4·8 months and 0·9 months, respectively (hazard ratio [HR] 0·27, 95% confidence interval [CI] 0·19–0·39; p<0·0001). Following progression, 56/66 patients (84·8%) on placebo crossed over to regorafenib, resulting in no significant difference in OS between study arms (HR 0·77, 95% CI 0·42–1·41; p=0·199). A best response of partial response or stable disease was observed in 101/133 patients (75·9%) on regorafenib and 23/66 patients (34·8%) on placebo. DCR was 52·6% (70/133 patients) and 9·1% (6/66 patients), respectively. Drug-related adverse events were reported in 130 (98·5%) of 132 regorafenib patients and 45 (68·2%) of 66 placebo patients. The most common grade ≥3 regorafenib

  14. Research on text encryption and hiding method with double-random phase-encoding

    NASA Astrophysics Data System (ADS)

    Xu, Hongsheng; Sang, Nong

    2013-10-01

    By using optical image processing techniques, a novel text encryption and hiding method applied by double-random phase-encoding technique is proposed in the paper. The first step is that the secret message is transformed into a 2- dimension array. The higher bits of the elements in the array are used to fill with the bit stream of the secret text, while the lower bits are stored specific values. Then, the transformed array is encoded by double random phase encoding technique. Last, the encoded array is embedded on a public host image to obtain the image embedded with hidden text. The performance of the proposed technique is tested via analytical modeling and test data stream. Experimental results show that the secret text can be recovered either accurately or almost accurately, while maintaining the quality of the host image embedded with hidden data by properly selecting the method of transforming the secret text into an array and the superimposition coefficient.

  15. Key management of the double random-phase-encoding method using public-key encryption

    NASA Astrophysics Data System (ADS)

    Saini, Nirmala; Sinha, Aloka

    2010-03-01

    Public-key encryption has been used to encode the key of the encryption process. In the proposed technique, an input image has been encrypted by using the double random-phase-encoding method using extended fractional Fourier transform. The key of the encryption process have been encoded by using the Rivest-Shamir-Adelman (RSA) public-key encryption algorithm. The encoded key has then been transmitted to the receiver side along with the encrypted image. In the decryption process, first the encoded key has been decrypted using the secret key and then the encrypted image has been decrypted by using the retrieved key parameters. The proposed technique has advantage over double random-phase-encoding method because the problem associated with the transmission of the key has been eliminated by using public-key encryption. Computer simulation has been carried out to validate the proposed technique.

  16. Pearson's random walk in the space of the CMB phases: Evidence for parity asymmetry

    SciTech Connect

    Hansen, M.; Frejsel, A. M.; Kim, J.; Naselsky, P.; Nesti, F.

    2011-05-15

    The temperature fluctuations of the cosmic microwave background (CMB) are supposed to be distributed randomly in both magnitude and phase, following to the simplest model of inflation. In this paper, we look at the odd and even multipoles of the spherical harmonic decomposition of the CMB, and the different characteristics of these, giving rise to a parity asymmetry. We compare the even and odd multipoles in the CMB power spectrum, and also the even and odd mean angles. We find for the multipoles of the power spectrum that there is power excess in odd multipoles, compared to even ones, meaning that we have a parity asymmetry. Further, for the phases, we present a random walk for the mean angles, and find a significant separation for even/odd mean angles, especially so for galactic coordinates. This is further tested and confirmed with a directional parity test, comparing the parity asymmetry in galactic and ecliptic coordinates.

  17. Chosen-plaintext attack on double-random-phase-encoding-based image hiding method

    NASA Astrophysics Data System (ADS)

    Xu, Hongsheng; Li, Guirong; Zhu, Xianchen

    2015-12-01

    By using optical image processing techniques, a novel text encryption and hiding method applied by double-random phase-encoding technique is proposed in the paper. The first step is that the secret message is transformed into a 2- dimension array. The higher bits of the elements in the array are used to fill with the bit stream of the secret text, while the lower bits are stored specific values. Then, the transformed array is encoded by double random phase encoding technique. Last, the encoded array is embedded on a public host image to obtain the image embedded with hidden text. The performance of the proposed technique is tested via analytical modeling and test data stream. Experimental results show that the secret text can be recovered either accurately or almost accurately, while maintaining the quality of the host image embedded with hidden data by properly selecting the method of transforming the secret text into an array and the superimposition coefficient.

  18. Phase-space representation and polarization domains of random electromagnetic fields.

    PubMed

    Castaneda, Roman; Betancur, Rafael; Herrera, Jorge; Carrasquilla, Juan

    2008-08-01

    The phase-space representation of stationary random electromagnetic fields is developed by using electromagnetic spatial coherence wavelets. The propagation of the field's power and states of spatial coherence and polarization results from correlations between the components of the field vectors at pairs of points in space. Polarization domains are theoretically predicted as the structure of the field polarization at the observation plane. In addition, the phase-space representation provides a generalization of the Poynting theorem. Theoretical predictions are examined by numerically simulating the Young experiment with electromagnetic waves. The experimental implementation of these results is a current subject of research. PMID:18670539

  19. Thermodynamic properties of hot nuclei within the self-consistent quasiparticle random-phase approximation

    SciTech Connect

    Hung, N. Quang; Dang, N. Dinh

    2010-10-15

    The thermodynamic properties of hot nuclei are described within the canonical and microcanonical ensemble approaches. These approaches are derived based on the solutions of the BCS and self-consistent quasiparticle random-phase approximation at zero temperature embedded into the canonical and microcanonical ensembles. The results obtained agree well with the recent data extracted from experimental level densities by the Oslo group for {sup 94}Mo, {sup 98}Mo, {sup 162}Dy, and {sup 172}Yb nuclei.

  20. Photoionization cross sections for atomic chlorine using an open-shell random phase approximation

    NASA Technical Reports Server (NTRS)

    Starace, A. F.; Armstrong, L., Jr.

    1975-01-01

    The use of the Random Phase Approximation with Exchange (RPAE) for calculating partial and total photoionization cross sections and photoelectron angular distributions for open shell atoms is examined for atomic chlorine. Whereas the RPAE corrections in argon (Z=18) are large, it is found that those in chlorine (Z=17) are much smaller due to geometric factors. Hartree-Fock calculations with and without core relaxation are also presented. Sizable deviations from the close coupling results of Conneely are also found.

  1. Test of finite temperature random-phase approximation on a Lipkin model

    SciTech Connect

    Hagino, K.; Minato, F.

    2009-10-15

    We investigate the applicability of the finite temperature random phase approximation (RPA) using a solvable Lipkin model. We show that the finite temperature RPA reproduces reasonably well the temperature dependence of total strength, both for the positive energy (i.e., the excitation) and the negative energy (i.e., the de-excitation) parts. This is the case even at very low temperatures, which may be relevant to astrophysical purposes.

  2. Vulnerability to chosen-cyphertext attacks of optical encryption schemes based on double random phase keys

    NASA Astrophysics Data System (ADS)

    Carnicer, Arturo; Montes-Usategui, Mario; Arcos, Sergio; Juvells, Ignacio

    2005-07-01

    We show how optical encryption methods based on double random phase keys are vulnerable to an organized attack of the chosen-ciphertext type. The decryption key can be easily obtained by an opponent who has repeated access to either the encryption or decryption machines. However, we have also devised a solution that prevents the attack. Our results cast doubts on the present security of these techniques.

  3. Improved light extraction from white organic light-emitting devices using a binary random phase array

    SciTech Connect

    Inada, Yasuhisa Nishiwaki, Seiji; Hirasawa, Taku; Nakamura, Yoshitaka; Hashiya, Akira; Wakabayashi, Shin-ichi; Suzuki, Masa-aki; Matsuzaki, Jumpei

    2014-02-10

    We have developed a binary random phase array (BRPA) to improve the light extraction performance of white organic light-emitting devices (WOLEDs). We demonstrated that the scattering of incoming light can be controlled by employing diffraction optics to modify the structural parameters of the BRPA. Applying a BRPA to the substrate of the WOLED leads to enhanced extraction efficiency and suppression of angle-dependent color changes. Our systematic study clarifies the effect of scattering on the light extraction of WOLEDs.

  4. The effects of monomer sequence distribution and isotopic substitution on solution phase behavior of random copolymers

    NASA Astrophysics Data System (ADS)

    Kuk Jhon, Young; Krishnamoorti, Ramanan; Genzer, Jan

    2008-03-01

    We report on the effect of chemical composition, co-monomer distribution and H/D isotopic substitution on the phase behavior in copolymers of poly(styrene-co-4-bromostyrene) (PBrxS), where x denotes the mole fraction of 4-bromostyrene (4-BrS), in cyclohexane. By adjusting the solvent quality during bromination of parent polystyrene, either random or random blocky PBrxS, (r-PBrxS or b-PBrxS, respectively), were synthesized. We studied the temperature dependence of phase behavior of PBrxS with various x in cyclohexane as a function of the polymer concentration using light scattering. Our results reveal that for a given 4-BrS content, the cloud points of b-PBrxS solutions are consistently higher and broader than those observed in r-PBrxS solutions. The transition temperature has also been found to depend on the isotope substitutions of H or D in either the polymer or the solvent. Small angle neutron scattering measurements indicate significant differences in the temperature dependence of the thermodynamic behavior for the random and blocky samples and the nature of the fluctuations upon approaching the phase boundaries.

  5. Vapour-liquid phase diagram for an ionic fluid in a random porous medium.

    PubMed

    Holovko, M F; Patsahan, O; Patsahan, T

    2016-10-19

    We study the vapour-liquid phase behaviour of an ionic fluid confined in a random porous matrix formed by uncharged hard sphere particles. The ionic fluid is modelled as an equimolar binary mixture of oppositely charged equisized hard spheres, the so-called restricted primitive model (RPM). Considering the matrix-fluid system as a partly-quenched model, we develop a theoretical approach which combines the method of collective variables with the extension of the scaled-particle theory (SPT) for a hard-sphere fluid confined in a disordered hard-sphere matrix. The approach allows us to formulate the perturbation theory using the SPT for the description of the thermodynamics of the reference system. The phase diagrams of the RPM in matrices of different porosities and for different size ratios of matrix and fluid particles are calculated in the random-phase approximation and also when the effects of higher-order correlations between ions are taken into account. Both approximations correctly reproduce the basic effects of porous media on the vapour-liquid phase diagram, i.e. with a decrease of porosity the critical point shifts towards lower fluid densities and lower temperatures and the coexistence region gets narrower. For the fixed matrix porosity, both the critical temperature and the critical density increase with an increase of size of matrix particles and tend to the critical values of the bulk RPM. PMID:27548356

  6. Molecular phase space transport in water: Non-stationary random walk model

    NASA Astrophysics Data System (ADS)

    Nerukh, Dmitry; Ryabov, Vladimir; Taiji, Makoto

    2009-11-01

    Molecular transport in phase space is crucial for chemical reactions because it defines how pre-reactive molecular configurations are found during the time evolution of the system. Using Molecular Dynamics (MD) simulated atomistic trajectories we test the assumption of the normal diffusion in the phase space for bulk water at ambient conditions by checking the equivalence of the transport to the random walk model. Contrary to common expectations we have found that some statistical features of the transport in the phase space differ from those of the normal diffusion models. This implies a non-random character of the path search process by the reacting complexes in water solutions. Our further numerical experiments show that a significant long period of non-stationarity in the transition probabilities of the segments of molecular trajectories can account for the observed non-uniform filling of the phase space. Surprisingly, the characteristic periods in the model non-stationarity constitute hundreds of nanoseconds, that is much longer time scales compared to typical lifetime of known liquid water molecular structures (several picoseconds).

  7. Single-phase and two-phase flow properties of mesaverde tight sandstone formation; random-network modeling approach

    NASA Astrophysics Data System (ADS)

    Bashtani, Farzad; Maini, Brij; Kantzas, Apostolos

    2016-08-01

    3D random networks are constructed in order to represent the tight Mesaverde formation which is located in north Wyoming, USA. The porous-space is represented by pore bodies of different shapes and sizes which are connected to each other by pore throats of varying length and diameter. Pore bodies are randomly distributed in space and their connectivity varies based on the connectivity number distribution which is used in order to generate the network. Network representations are then validated using publicly available mercury porosimetry experiments. The network modeling software solves the fundamental equations of two-phase immiscible flow incorporating wettability and contact angle variability. Quasi-static displacement is assumed. Single phase macroscopic properties (porosity, permeability) are calculated and whenever possible are compared to experimental data. Using this information drainage and imbibition capillary pressure, and relative permeability curves are predicted and (whenever possible) compared to experimental data. The calculated information is grouped and compared to available literature information on typical behavior of tight formations. Capillary pressure curve for primary drainage process is predicted and compared to experimental mercury porosimetry in order to validate the virtual porous media by history matching. Relative permeability curves are also calculated and presented.

  8. Many-body localization phase transition: A simplified strong-randomness approximate renormalization group

    NASA Astrophysics Data System (ADS)

    Zhang, Liangsheng; Zhao, Bo; Devakul, Trithep; Huse, David A.

    2016-06-01

    We present a simplified strong-randomness renormalization group (RG) that captures some aspects of the many-body localization (MBL) phase transition in generic disordered one-dimensional systems. This RG can be formulated analytically and is mathematically equivalent to a domain coarsening model that has been previously solved. The critical fixed-point distribution and critical exponents (that satisfy the Chayes inequality) are thus obtained analytically or to numerical precision. This reproduces some, but not all, of the qualitative features of the MBL phase transition that are indicated by previous numerical work and approximate RG studies: our RG might serve as a "zeroth-order" approximation for future RG studies. One interesting feature that we highlight is that the rare Griffiths regions are fractal. For thermal Griffiths regions within the MBL phase, this feature might be qualitatively correctly captured by our RG. If this is correct beyond our approximations, then these Griffiths effects are stronger than has been previously assumed.

  9. Sorafenib in locally advanced or metastatic, radioactive iodine-refractory, differentiated thyroid cancer: a randomized, double-blind, phase 3 trial

    PubMed Central

    Brose, Marcia S; Nutting, Christopher M; Jarzab, Barbara; Elisei, Rossella; Siena, Salvatore; Bastholt, Lars; de la Fouchardiere, Christelle; Pacini, Furio; Paschke, Ralf; KeeShong, Young; Sherman, Steven I; Smit, Johannes WA; Chung, John; Kappeler, Christian; Pena, Carol; Molnár, István; Schlumberger, Martin J

    2015-01-01

    Background Patients with radioactive iodine (131I, RAI)-refractory locally advanced or metastatic differentiated thyroid cancer (DTC) have a poor prognosis due to the lack of effective treatment options. Methods This multicentre, randomized (1:1), double-blind, placebo-controlled, phase 3 study (DECISION; NCT00984282) investigated sorafenib (400 mg orally twice-daily) in patients with RAI-refractory locally advanced or metastatic DTC progressing within the past 14 months. The primary endpoint was progression-free survival (PFS) by central independent review. Patients receiving placebo could crossover to open-label sorafenib upon progression. Archival tumour tissue was examined for BRAF and RAS mutations. Serum thyroglobulin was measured at baseline and each visit. Findings A total of 417 patients were randomized to sorafenib (n=207) or placebo (n=210). Sorafenib treatment significantly improved PFS compared with placebo (hazard ratio, 0·59; 95% confidence interval, 0·45–0·76; P<0·0001; median 10·8 vs. 5·8 months, respectively). PFS improvement was seen in all pre-specified clinical and genetic biomarker subgroups irrespective of mutation status. There was no statistically significant difference in overall survival (hazard ratio, 0·80; 95% confidence interval, 0·54–1·19; P=0·14); median overall survival had not been reached and 150 (71%) patients receiving placebo crossed over to sorafenib upon progression. Response rates (all partial responses) were 12·2% (24/196; sorafenib) and 0·5% (1/201; placebo; p<0·0001). Median thyroglobulin levels increased in the placebo group, and decreased, then paralleled treatment responses in the sorafenib group. Most adverse events were grade 1 or 2. The most common treatment-emergent adverse events in the sorafenib arm were hand–foot skin reaction (76·3%), diarrhoea (68·6%), alopecia (67·1%), and rash/desquamation (50·2%). Interpretation Sorafenib significantly improved PFS compared with placebo in patients

  10. Low crosstalk optical hierarchical authentication with a fixed random phase lock based on two beams interference

    NASA Astrophysics Data System (ADS)

    Lu, Dajiang; He, Wenqi; Peng, Xiang

    2015-09-01

    We propose a novel method to achieve the purpose of hierarchical authentication based on two beams interference. In this method, different target images indicating different authentication levels are analytically encoded into corresponding phase-only masks (phase keys) and amplitude-only masks (amplitude keys) with the help of a random phase mask, which is created in advance and acts as the fixed lock of this authentication system. For the authentication process, a legal user can obtain a specified target image at the output plane if his/her phase key, and amplitude key, which should be settled close against the fixed internal phase lock, are respectively illuminated by two coherent beams. By comparing the target image with all the standard certification images in the database, the system can thus verify the user's identity. In simple terms, this system can not only confirm the legality of a user but also distinguish his/her identity level. Moreover, in despite of the internal phase lock of this system being fixed, the crosstalk between different pairs of keys hold by different users is low. Theoretical analysis and numerical simulation are both provided to demonstrate the validity of this method.

  11. Fixation using alternative implants for the treatment of hip fractures (FAITH): design and rationale for a multi-centre randomized trial comparing sliding hip screws and cancellous screws on revision surgery rates and quality of life in the treatment of femoral neck fractures

    PubMed Central

    2014-01-01

    Background Hip fractures are a common type of fragility fracture that afflict 293,000 Americans (over 5,000 per week) and 35,000 Canadians (over 670 per week) annually. Despite the large population impact the optimal fixation technique for low energy femoral neck fractures remains controversial. The primary objective of the FAITH study is to assess the impact of cancellous screw fixation versus sliding hip screws on rates of revision surgery at 24 months in individuals with femoral neck fractures. The secondary objective is to determine the impact on health-related quality of life, functional outcomes, health state utilities, fracture healing, mortality and fracture-related adverse events. Methods/Design FAITH is a multi-centre, multi-national randomized controlled trial utilizing minimization to determine patient allocation. Surgeons in North America, Europe, Australia, and Asia will recruit a total of at least 1,000 patients with low-energy femoral neck fractures. Using central randomization, patients will be allocated to receive surgical treatment with cancellous screws or a sliding hip screw. Patient outcomes will be assessed at one week (baseline), 10 weeks, 6, 12, 18, and 24 months post initial fixation. We will independently adjudicate revision surgery and complications within 24 months of the initial fixation. Outcome analysis will be performed using a Cox proportional hazards model and likelihood ratio test. Discussion This study represents major international efforts to definitively resolve the treatment of low-energy femoral neck fractures. This trial will not only change current Orthopaedic practice, but will also set a benchmark for the conduct of future Orthopaedic trials. Trial registration The FAITH trial is registered at ClinicalTrials.gov (Identifier NCT00761813). PMID:24965132

  12. Generalized Hammersley Process and Phase Transition for Activated Random Walk Models

    NASA Astrophysics Data System (ADS)

    Rolla, Leonardo T.

    2008-12-01

    * ACTIVATED RANDOM WALK MODEL * This is a conservative particle system on the lattice, with a Markovian continuous-time evolution. Active particles perform random walks without interaction, and they may as well change their state to passive, then stopping to jump. When particles of both types occupy the same site, they all become active. This model exhibits phase transition in the sense that for low initial densities the system locally fixates and for high densities it keeps active. Though extensively studied in the physics literature, the matter of giving a mathematical proof of such phase transition remained as an open problem for several years. In this work we identify some variables that are sufficient to characterize fixation and at the same time are stochastically monotone in the model's parameters. We employ an explicit graphical representation in order to obtain the monotonicity. With this method we prove that there is a unique phase transition for the one-dimensional finite-range random walk. Joint with V. Sidoravicius. * BROKEN LINE PROCESS * We introduce the broken line process and derive some of its properties. Its discrete version is presented first and a natural generalization to the continuum is then proposed and studied. The broken lines are related to the Young diagram and the Hammersley process and are useful for computing last passage percolation values and finding maximal oriented paths. For a class of passage time distributions there is a family of boundary conditions that make the process stationary and reversible. One application is a simple proof of the explicit law of large numbers for last passage percolation with exponential and geometric distributions. Joint with V. Sidoravicius, D. Surgailis, and M. E. Vares.

  13. Gyrator transform based double random phase encoding with sparse representation for information authentication

    NASA Astrophysics Data System (ADS)

    Chen, Jun-xin; Zhu, Zhi-liang; Fu, Chong; Yu, Hai; Zhang, Li-bo

    2015-07-01

    Optical information security systems have drawn long-term concerns. In this paper, an optical information authentication approach using gyrator transform based double random phase encoding with sparse representation is proposed. Different from traditional optical encryption schemes, only sparse version of the ciphertext is preserved, and hence the decrypted result is completely unrecognizable and shows no similarity to the plaintext. However, we demonstrate that the noise-like decipher result can be effectively authenticated by means of optical correlation approach. Simulations prove that the proposed method is feasible and effective, and can provide additional protection for optical security systems.

  14. Reconstruction of photon number conditioned states using phase randomized homodyne measurements

    NASA Astrophysics Data System (ADS)

    Chrzanowski, H. M.; Assad, S. M.; Bernu, J.; Hage, B.; Lund, A. P.; Ralph, T. C.; Lam, P. K.; Symul, T.

    2013-05-01

    We experimentally demonstrate the reconstruction of a photon number conditioned state without using a photon number discriminating detector. By using only phase randomized homodyne measurements, we reconstruct up to the three photon subtracted squeezed vacuum state. The reconstructed Wigner functions of these states show regions of pronounced negativity, signifying the non-classical nature of the reconstructed states. The techniques presented allow for complete characterization of the role of a conditional measurement on an ensemble of states, and might prove useful in systems where photon counting still proves technically challenging.

  15. Self-consistent relativistic random-phase approximation with vacuum polarization

    SciTech Connect

    Haga, A.; Toki, H.; Tamenaga, S.; Horikawa, Y.; Yadav, H.L.

    2005-09-01

    We present a theoretical formulation for the description of nuclear excitations within the framework of a relativistic random-phase approximation whereby the vacuum polarization arising from nucleon-antinucleon fields is duly accounted for. The vacuum contribution to the Lagrangian is explicitly described as extra new terms of interacting mesons by means of the derivative expansion of the effective action. It is shown that the self-consistent calculation yields zero eigenvalue for the spurious isoscalar-dipole state and also conserves the vector-current density.

  16. Broadband diffuse reflections of sound by metasurface with random phase response

    NASA Astrophysics Data System (ADS)

    Gu, Zhong-ming; Liang, Bin; Zou, Xin-ye; Cheng, Jian-chun

    2015-09-01

    We have designed an ultrathin planar structure capable of generating diffuse reflections within a broadband. By introducing randomly distributed gradients along the interface, the proposed structure can scatter the incident acoustic waves into all directions and virtually suppress the scattered lobes that will otherwise be remarkable for a planar surface. A practical implementation by labryinthine-like metamaterial with designed phase shift profile is demontrated. The numerical results show that our designed planar surface could be used to mimic a rugged surface as expected. We envision our designed structure to exhibit potentials in applications such as room acoustics and acoustic stealth.

  17. Random fields and the weakly first-order phase transition in superconductors

    SciTech Connect

    Busiello, G.; De Cesare, L.; Uzunov, D.I.

    1986-10-01

    We study the influence of random fields with short-range and long-range correlations on the weakly first-order phase transition in superconductors. Renormalization-group (RG) analysis near the upper critical dimensionality d/sub u/ = 6 (short-range correlations) reveals a new critical behavior which holds if the number of the order-parameter components is n>10. In the long-range case, the RG transformation is self-consistent only if the parameter theta of the long-range correlations is assumed of order epsilon, epsilon = 6-d.

  18. Self-consistent continuum random-phase approximation calculations of {sup 4}He electromagnetic responses

    SciTech Connect

    De Donno, V.; Co', G.; Anguiano, M.; Lallena, A. M.

    2011-09-15

    We study the electromagnetic responses of {sup 4}He within the framework of the self-consistent continuum random-phase approximation theory. In this approach, the ground-state properties are described by a Hartree-Fock calculation. The single-particle basis constructed in this manner is used in the calculations of the continuum responses of the system. Finite-range interactions are considered in the calculations. We compare our results with photon-absorption cross sections and electron-scattering quasielastic data. From this comparison, and also from the comparison with the results of microscopic calculations, we deduce that our approach describes well the continuum excitation.

  19. Speckle suppression in digital holographic imaging with random phases and different wavelengths

    NASA Astrophysics Data System (ADS)

    Leng, Junmin; Sang, Xinzhu; Yan, Binbin

    2014-03-01

    An effective speckle suppression method in digital holography is experimentally demonstrated with a wavelength-tunable coherent light source and a moving diffuser. Multiple off-axis digital holograms with different wavelengths and random phases are obtained. The Fresnel transformation algorithm is used to calculate the diffraction integral in the reconstruction. The speckle noise in the reconstructed images is suppressed by superposing and averaging the intensity of multiple reconstruction images. Experiment results and the parameter evaluation show that the presented method is effective and feasible.

  20. Implementation of the finite amplitude method for the relativistic quasiparticle random-phase approximation

    NASA Astrophysics Data System (ADS)

    Nikšić, T.; Kralj, N.; Tutiš, T.; Vretenar, D.; Ring, P.

    2013-10-01

    A new implementation of the finite amplitude method (FAM) for the solution of the relativistic quasiparticle random-phase approximation (RQRPA) is presented, based on the relativistic Hartree-Bogoliubov (RHB) model for deformed nuclei. The numerical accuracy and stability of the FAM-RQRPA is tested in a calculation of the monopole response of 22O. As an illustrative example, the model is applied to a study of the evolution of monopole strength in the chain of Sm isotopes, including the splitting of the giant monopole resonance in axially deformed systems.

  1. Microstructural Characterization in Reliability Measurement of Phase Change Random Access Memory

    NASA Astrophysics Data System (ADS)

    Bae, Junsoo; Hwang, Kyuman; Park, Kwangho; Jeon, Seongbu; Kang, Dae-hwan; Park, Soonoh; Ahn, Juhyeon; Kim, Seoksik; Jeong, Gitae; Chung, Chilhee

    2011-04-01

    The cell failures after cycling endurance in phase-change random access memory (PRAM) have been classified into three groups, which have been analyzed by transmission electron microscopy (TEM). Both stuck reset of the set state (D0) and stuck set of the reset state (D1) are due to a void created inside GeSbTe (GST) film or thereby lowering density of GST film. The decrease of the both set and reset resistances that leads to the tails from the reset distribution are induced from the Sb increase with cycles.

  2. Quantum Monte Carlo method using phase-free random walks with slater determinants.

    PubMed

    Zhang, Shiwei; Krakauer, Henry

    2003-04-01

    We develop a quantum Monte Carlo method for many fermions using random walks in the space of Slater determinants. An approximate approach is formulated with a trial wave function |Psi(T)> to control the phase problem. Using a plane-wave basis and nonlocal pseudopotentials, we apply the method to Be, Si, and P atoms and dimers, and to bulk Si supercells. Single-determinant wave functions from density functional theory calculations were used as |Psi(T)> with no additional optimization. The calculated binding energies of dimers and cohesive energy of bulk Si are in excellent agreement with experiments and are comparable to the best existing theoretical results. PMID:12689312

  3. Computer and graphics modeling of heat transfer and phase change in a wall with randomly imbibed PCM

    SciTech Connect

    Solomon, A.D.

    1989-03-01

    We describe the theoretical basis and computer implementation of a simulation code for heat transfer and phase change in a rectangular 2-dimensional region in which PCM has been randomly placed with a preassigned volume fraction.

  4. Magnetic first-order phase transition and crossover associated with random anisotropy in crystalline Dy[sub [ital x

    SciTech Connect

    del Moral, A.; Arnaudas, J.I. ); Gehring, P.M. ); Salamon, M.B. ); Ritter, C. ); Joven, E. ); Cullen, J. (Magnetics Group, Naval Surface Warfare Center, 10901 New Hampshire Avenue, White Oak, Silver Spring, Maryland 20903-5000 (United State

    1993-04-01

    The low-temperature ([ital T]=0 K) first-order phase transition, predicted to drive systems with both weak random and uniform cubic anisotropy from a correlated spin glass to a ferromagnet, has been observed. At higher temperatures the transition is to a quasi- or random ferromagnet. The transition occurs at a concentration [ital x][sub [ital t

  5. High energy X-ray phase and dark-field imaging using a random absorption mask

    NASA Astrophysics Data System (ADS)

    Wang, Hongchang; Kashyap, Yogesh; Cai, Biao; Sawhney, Kawal

    2016-07-01

    High energy X-ray imaging has unique advantage over conventional X-ray imaging, since it enables higher penetration into materials with significantly reduced radiation damage. However, the absorption contrast in high energy region is considerably low due to the reduced X-ray absorption cross section for most materials. Even though the X-ray phase and dark-field imaging techniques can provide substantially increased contrast and complementary information, fabricating dedicated optics for high energies still remain a challenge. To address this issue, we present an alternative X-ray imaging approach to produce transmission, phase and scattering signals at high X-ray energies by using a random absorption mask. Importantly, in addition to the synchrotron radiation source, this approach has been demonstrated for practical imaging application with a laboratory-based microfocus X-ray source. This new imaging method could be potentially useful for studying thick samples or heavy materials for advanced research in materials science.

  6. Dual-channel in-line digital holographic double random phase encryption

    PubMed Central

    Das, Bhargab; Yelleswarapu, Chandra S; Rao, D V G L N

    2012-01-01

    We present a robust encryption method for the encoding of 2D/3D objects using digital holography and virtual optics. Using our recently developed dual-plane in-line digital holography technique, two in-line digital holograms are recorded at two different planes and are encrypted using two different double random phase encryption configurations, independently. The process of using two mutually exclusive encryption channels makes the system more robust against attacks since both the channels should be decrypted accurately in order to get a recognizable reconstruction. Results show that the reconstructed object is unrecognizable even when the portion of the correct phase keys used during decryption is close to 75%. The system is verified against blind decryptions by evaluating the SNR and MSE. Validation of the proposed method and sensitivities of the associated parameters are quantitatively analyzed and illustrated. PMID:23471012

  7. Information hiding based on double random-phase encoding and public-key cryptography.

    PubMed

    Sheng, Yuan; Xin, Zhou; Alam, Mohammed S; Xi, Lu; Xiao-Feng, Li

    2009-03-01

    A novel information hiding method based on double random-phase encoding (DRPE) and Rivest-Shamir-Adleman (RSA) public-key cryptosystem is proposed. In the proposed technique, the inherent diffusion property of DRPE is cleverly utilized to make up the diffusion insufficiency of RSA public-key cryptography, while the RSA cryptosystem is utilized for simultaneous transmission of the cipher text and the two phase-masks, which is not possible under the DRPE technique. This technique combines the complementary advantages of the DPRE and RSA encryption techniques and brings security and convenience for efficient information transmission. Extensive numerical simulation results are presented to verify the performance of the proposed technique. PMID:19259163

  8. Low-noise multiple watermarks technology based on complex double random phase encoding method

    NASA Astrophysics Data System (ADS)

    Zheng, Jihong; Lu, Rongwen; Sun, Liujie; Zhuang, Songlin

    2010-11-01

    Based on double random phase encoding method (DRPE), watermarking technology may provide a stable and robust method to protect the copyright of the printing. However, due to its linear character, DRPE exist the serious safety risk when it is attacked. In this paper, a complex coding method, which means adding the chaotic encryption based on logistic mapping before the DRPE coding, is provided and simulated. The results testify the complex method will provide better security protection for the watermarking. Furthermore, a low-noise multiple watermarking is studied, which means embedding multiple watermarks into one host printing and decrypt them with corresponding phase keys individually. The Digital simulation and mathematic analysis show that with the same total embedding weight factor, multiply watermarking will improve signal noise ratio (SNR) of the output printing image significantly. The complex multiply watermark method may provide a robust, stability, reliability copyright protection with higher quality printing image.

  9. Pseudo-random binary sequence phase modulation for narrow linewidth, kilowatt, monolithic fiber amplifiers.

    PubMed

    Flores, Angel; Robin, Craig; Lanari, Ann; Dajani, Iyad

    2014-07-28

    We report on pseudo random binary sequence (PRBS) phase modulation for narrow-linewidth, kilowatt-class, monolithic (all-fiber) amplifiers. Stimulated Brillouin scattering (SBS) threshold enhancement factors for different patterns of PRBS modulated fiber amplifiers were experimentally analyzed and agreed well with the theoretical predictions. We also examined seeding of the SBS process by phase modulated signals when the effective linewidth is on the same order as the Brillouin shift frequency. Here ~30% variations in SBS power thresholds were observed from small tunings of the modulation frequency. In addition, a 3 GHz PRBS modulated, 1.17 kW fiber amplifier was demonstrated. Near diffraction-limited beam quality was achieved (M2 = 1.2) with an optical pump efficiency of 83%. Overall, the improved SBS suppression and narrow linewidth achieved through PRBS modulation can have a significant impact on the beam combining of kilowatt class fiber lasers. PMID:25089393

  10. Pseudo-random binary sequency phase modulation in high power Yb-doped fiber amplifiers

    NASA Astrophysics Data System (ADS)

    Robin, Craig; Dajani, Iyad; Zernigue, Clint; Flores, Angel; Pulford, Ben; Lanari, Ann; Naderi, Shadi

    2013-03-01

    We present experimental and theoretical studies on the stimulated Brillouin scattering (SBS) threshold in fiber amplifiers seeded with a spectrally broadened single-frequency laser source. An electro-optic phase modulator is driven with various pseudo-random binary sequence (PRBS) patterns to highlight the unique characteristics of this linewidth broadening technique and its facility in SBS mitigation. Theoretical predictions show a variation in SBS suppression based on PRBS pattern and modulation frequency. These predictions are experimentally investigated in a kilowatt level monolithic fiber amplifier operating with near diffraction-limited beam quality. We also show Rayleigh scattering and other sources of back reflected light in phase modulated signals can seed the SBS process and significantly reduce the nonlinear threshold.

  11. Deviations from the mean-field predictions for the phase behaviour of random copolymers melts

    NASA Astrophysics Data System (ADS)

    Houdayer, J.; Müller, M.

    2002-06-01

    We investigate the phase behaviour of random copolymers melts via large-scale Monte Carlo simulations. We observe macrophase separation into A- and B-rich phases as predicted by the mean-field theory only for systems with a very large correlation λ of blocks along the polymer chains, far away from the Lifshitz point. For smaller values of λ, we find that a locally segregated, disordered microemulsion-like structure gradually forms as the temperature decreases. As we increase the number of blocks in the polymers, the region of macrophase separation further shrinks. The results of our Monte Carlo simulation are in agreement with a Ginzburg criterium, which suggests that the mean-field theory becomes worse as the number of blocks in polymers increases.

  12. Color computer-generated hologram generation using the random phase-free method and color space conversion.

    PubMed

    Shimobaba, Tomoyoshi; Makowski, Michał; Nagahama, Yuki; Endo, Yutaka; Hirayama, Ryuji; Hiyama, Daisuke; Hasegawa, Satoki; Sano, Marie; Kakue, Takashi; Oikawa, Minoru; Sugie, Takashige; Takada, Naoki; Ito, Tomoyoshi

    2016-05-20

    We propose two calculation methods of generating color computer-generated holograms (CGHs) with the random phase-free method and color space conversion in order to improve the image quality and accelerate the calculation. The random phase-free method improves the image quality in monochrome CGH, but it is not performed in color CGH. We first aimed to improve the image quality of color CGH using the random phase-free method and then to accelerate the color CGH generation with a combination of the random phase-free method and color space conversion method, which accelerates the color CGH calculation due to down-sampling of the color components converted by color space conversion. To overcome the problem of image quality degradation that occurs due to the down-sampling of random phases, the combination of the random phase-free method and color space conversion method improves the quality of reconstructed images and accelerates the color CGH calculation. We demonstrated the effectiveness of the proposed method in simulation, and in this paper discuss its application to lensless zoomable holographic projection. PMID:27411145

  13. Equivalence of particle-particle random phase approximation correlation energy and ladder-coupled-cluster doubles.

    PubMed

    Peng, Degao; Steinmann, Stephan N; van Aggelen, Helen; Yang, Weitao

    2013-09-14

    The recent proposal to determine the (exact) correlation energy based on pairing matrix fluctuations by van Aggelen et al. ["Exchange-correlation energy from pairing matrix fluctuation and the particle-particle random phase approximation," preprint arXiv:1306.4957 (2013)] revived the interest in the simplest approximation along this path: the particle-particle random phase approximation (pp-RPA). In this paper, we present an analytical connection and numerical demonstrations of the equivalence of the correlation energy from pp-RPA and ladder-coupled-cluster doubles. These two theories reduce to identical algebraic matrix equations and correlation energy expressions. The numerical examples illustrate that the correlation energy missed by pp-RPA in comparison with coupled-cluster singles and doubles is largely canceled out when considering reaction energies. This theoretical connection will be beneficial to design density functionals with strong ties to coupled-cluster theories and to study molecular properties at the pp-RPA level relying on well established coupled cluster techniques. PMID:24050333

  14. Nuclear excitations as coupled one and two random-phase-approximation modes

    NASA Astrophysics Data System (ADS)

    Gambacurta, D.; Catara, F.; Grasso, M.; Sambataro, M.; Andrés, M. V.; Lanza, E. G.

    2016-02-01

    We present an extension of the random-phase approximation (RPA) where the RPA phonons are used as building blocks to construct the excited states. In our model, that we call double RPA (DRPA), we include up to two RPA phonons. This is an approximate and simplified way, with respect to the full second random-phase approximation (SRPA), to extend the RPA by including two-particle-two-hole configurations. Some limitations of the standard SRPA model, related to the violation of the stability condition, are not encountered in the DRPA. We also verify in this work that the energy-weighted sum rules are satisfied. The DRPA is applied to low-energy modes and giant resonances in the nucleus 16O. We show that the model (i) produces a global downwards shift of the energies with respect to the RPA spectra and (ii) provides a shift that is, however, strongly reduced compared to that generated by the standard SRPA. This model represents an alternative way of correcting for the SRPA anomalous energy shift, compared to a recently developed extension of the SRPA, where a subtraction procedure is applied. The DRPA provides results in good agreement with the experimental energies, with the exception of those low-lying states that have a dominant two-particle-two-hole nature. For describing such states, higher-order calculations are needed.

  15. Self-consistent extension of random-phase approximation enlarged beyond particle-hole configurations

    SciTech Connect

    Gambacurta, Danilo; Catara, Francesco; Grasso, Marcella

    2009-07-15

    We present a new extension of the random-phase approximation method: the quasiboson approximation is avoided and correlations are included in the ground state without resorting to renormalized operators or renormalized matrix elements; the configuration space is enlarged by considering also elementary excitations corresponding to the annihilation of a particle (hole) and the creation of another particle (hole) on the correlated ground state, together with the particle-hole ones. Two new and relevant advantages of this method with respect to the existing extensions of random-phase approximation are highlighted: (i) the energy weighted sum rules are completely satisfied; (ii) the problem of the existence of nonphysical states in the spectrum, related to the inclusion of particle-particle and hole-hole configurations, is solved: a way to unambiguously disentangle physical from nonphysical states in the excitation spectrum is presented. The method is applied here to a three-level Lipkin model where its quality can be judged by comparing with the exact results. Both advantages (i) and (ii) shall lead to feasible future applications of this extended RPA to several realistic cases.

  16. Application of a Boson Expansion formalism based on the Random Phase Approximation to samarium isotopes

    SciTech Connect

    Jamaluddin, M.B.

    1986-01-01

    The Boson Expansion Theory of Kishimoto and Tamura has proved to be very successful in describing quadrupole collective motions in even-even nuclei. This theory, however, involves a complicated transformation from the Tamm-Dancoff phonons to the phonons of the random Phase Approximation. In this thesis a Boson Expansion formalism, derived directly from the Random Phase Approximation and set forth by Pedracchi and Tamura, is used to derive the boson forms of the nuclear Hamiltonian and the electromagnetic transition operator. Detailed discussions of the formalism of Pedrocchi and Tamura and its extension needed to perform realistic calculations are presented. The technique used to deriving the boson forms and the formulae used in the calculations are also given a thorough treatment to demonstrate the simplicity of this approach. Finally, the theory is tested by applying it to calculate the energy levels and some electromagnetic properties of the Samarium isotopes. The results show that the present theory is capable of describing the range of behavior from a vibrational to a rotational character of the Samarium isotopes as well as the previous theory.

  17. Efficient Text Encryption and Hiding with Double-Random Phase-Encoding

    PubMed Central

    Sang, Jun; Ling, Shenggui; Alam, Mohammad S.

    2012-01-01

    In this paper, a double-random phase-encoding technique-based text encryption and hiding method is proposed. First, the secret text is transformed into a 2-dimensional array and the higher bits of the elements in the transformed array are used to store the bit stream of the secret text, while the lower bits are filled with specific values. Then, the transformed array is encoded with double-random phase-encoding technique. Finally, the encoded array is superimposed on an expanded host image to obtain the image embedded with hidden data. The performance of the proposed technique, including the hiding capacity, the recovery accuracy of the secret text, and the quality of the image embedded with hidden data, is tested via analytical modeling and test data stream. Experimental results show that the secret text can be recovered either accurately or almost accurately, while maintaining the quality of the host image embedded with hidden data by properly selecting the method of transforming the secret text into an array and the superimposition coefficient. By using optical information processing techniques, the proposed method has been found to significantly improve the security of text information transmission, while ensuring hiding capacity at a prescribed level. PMID:23202003

  18. Optical cryptosystem of color images using random phase masks in the fractional wavelet transform domain

    NASA Astrophysics Data System (ADS)

    Singh, Hukum

    2016-05-01

    An optical color image encryption in the Fractional Wavelet Transform (FWT) domain is carried out. The original images are segregated into three colors components: R (red), G (green) and B (blue). After that the components are encrypted separately using double random phase encoding (DRPE) in the FWT domain. Random phase masks (RPMs) are used in the input as well as in Fourier plane. The images to be encrypted are transformed with the discrete wavelet transform (DWT), the resulting coefficients from the DWT are multiplied each one by masks different form RPM. Masks are independent each other and the results are applied an inverse discrete Wavelet Transform (IDWT), obtaining the encrypted images. The input images are recovered from their corresponding encrypted images by using the correct parameters of the FWT, and its digital implementation has been performed using MATLAB 7.6.0 (R2008a). The mother wavelet family and fractional orders associated with the FWT are extra keys that access difficulty an attacker; thereby the scheme is more secure as compared to conventional techniques. The sensitivity of proposed scheme is verified with encryption parameters, occlusions, and noise attacks.

  19. Diagnosis of the phase function of random media from light reflectance

    NASA Astrophysics Data System (ADS)

    Xu, Min

    2016-03-01

    Light reflectance has been widely used to diagnose random media in both in situ and in vivo applications. The quantification of the phase function of the medium from reflectance measurements, however, remains elusive due to the lack of an explicit connection between the light reflectance profile and the phase function. Here we first present an analytical model for reflectance of scattered light at an arbitrary source-detector separation by forward-peaked scattering media such as biological tissue and cells. The model incorporates the improved small-angle scattering approximation (SAA) to radiative transfer for sub-diffusive light reflectance and expresses the dependence of the light reflectance on the phase function of the scattering medium in a closed form. A spreading length scale, lΘ, is found to characterise subdiffusive light reflectance at the high spatial frequency (close separation) limit. After validation by Monte Carlo simulations, we then demonstrate the application of the model in accurate determination of the complete set of optical properties and the phase function of a turbid medium from the profile of subdiffusive and diffusive light reflectance.

  20. Diagnosis of the phase function of random media from light reflectance

    PubMed Central

    Xu, Min

    2016-01-01

    Light reflectance has been widely used to diagnose random media in both in situ and in vivo applications. The quantification of the phase function of the medium from reflectance measurements, however, remains elusive due to the lack of an explicit connection between the light reflectance profile and the phase function. Here we first present an analytical model for reflectance of scattered light at an arbitrary source-detector separation by forward-peaked scattering media such as biological tissue and cells. The model incorporates the improved small-angle scattering approximation (SAA) to radiative transfer for sub-diffusive light reflectance and expresses the dependence of the light reflectance on the phase function of the scattering medium in a closed form. A spreading length scale, lΘ, is found to characterise subdiffusive light reflectance at the high spatial frequency (close separation) limit. After validation by Monte Carlo simulations, we then demonstrate the application of the model in accurate determination of the complete set of optical properties and the phase function of a turbid medium from the profile of subdiffusive and diffusive light reflectance. PMID:26935167

  1. Viewing angle enhancement for two- and three-dimensional holographic displays with random superresolution phase masks

    NASA Astrophysics Data System (ADS)

    Buckley, Edward; Cable, Adrian; Lawrence, Nic; Wilkinson, Tim

    2006-10-01

    Holographic displays employing binary phase modulation have been demonstrated to be attractive on the grounds of efficiency and miniaturization, and they offer a plausible approach to two-dimensional (2D) and three-dimensional (3D) image projection and display. A novel algorithm--one-step phase retrieval--and corresponding hardware architecture have recently been proposed, providing the performance required for real-time holographic display. However, since viewing angle varies inversely with pixel size, very small display pixels are required to achieve a wide field of view. This is particularly problematic for 3D displays, as the requirement for a large display with small pixels has hitherto necessitated an unachievably large electrical bandwidth. We present a novel approach, utilizing fixed random pixelated quaternary phase masks of greater resolution than the displayed hologram, to dramatically increase the viewing angle for 2D and 3D holographic displays without incurring a bandwidth penalty or significantly degrading image quality. Furthermore, an algorithm is presented to generate holograms accounting for the presence of such a phase mask, so that only one mask is required.

  2. Multicentric malignant gastrointestinal stromal tumor.

    PubMed

    Shukla, Shailaja; Singh, Sanjeet K; Pujani, Mukta

    2009-01-01

    Malignant gastrointestinal stromal tumor (GIST) is a rare type of sarcoma that is found in the digestive system, most often in the wall of the stomach. Multiple GISTs are extremely rare and usually associated with type 1 neurofibromatosis and familial GIST.We report here a case of a 70-year-old woman who reported pain in the abdomen, loss of appetite, and weight loss for six months. Ultrasound examination showed a small bowel mass along with multiple peritoneal deposits and a mass within the liver. Barium studies were suggestive of a neoplastic pathology of the distal ileum. A differential diagnosis of adenocarcinoma/lymphoma with metastases was entertained. Perioperative findings showed two large growths arising from the jejunum and the distal ileum, along with multiple smaller nodules on the serosal surface and adjoining mesentery of the involved bowel segments. Segmental resection of the involved portions of the intestine was performed. Histopathological features were consistent with those of multicentric malignant GIST-not otherwise specified (GIST-NOS). Follow-up examination three months after surgery showed no evidence of recurrence. PMID:19568556

  3. Therapeutic Intervention in Multiple Sclerosis with Alpha B-Crystallin: A Randomized Controlled Phase IIa Trial

    PubMed Central

    van Noort, Johannes M.; Bsibsi, Malika; Nacken, Peter J.; Verbeek, Richard; Venneker, Edna H.G.

    2015-01-01

    As a molecular chaperone and activator of Toll-like receptor 2-mediated protective responses by microglia and macrophages, the small heat shock protein alpha B-crystallin (HspB5) exerts therapeutic effects in different animal models for neuroinflammation, including the model for multiple sclerosis (MS). Yet, HspB5 can also stimulate human antigen-specific memory T cells to release IFN-γ, a cytokine with well-documented detrimental effects during MS. In this study, we explored in a Phase IIa randomized clinical trial the therapeutic application of HspB5 in relapsing-remitting MS (RR-MS), using intravenous doses sufficient to support its protective effects, but too low to trigger pathogenic memory T-cell responses. These sub-immunogenic doses were selected based on in vitro analysis of the dose-response profile of human T cells and macrophages to HspB5, and on the immunological effects of HspB5 in healthy humans as established in a preparatory Phase I study. In a 48-week randomized, placebo-controlled, double-blind Phase IIa trial, three bimonthly intravenous injections of 7.5, 12.5 or 17.5 mg HspB5 were found to be safe and well tolerated in RR-MS patients. While predefined clinical endpoints did not differ significantly between the relatively small groups of MS patients treated with either HspB5 or placebo, repeated administration especially of the lower doses of HspB5 led to a progressive decline in MS lesion activity as monitored by magnetic resonance imaging (MRI), which was not seen in the placebo group. Exploratory linear regression analysis revealed this decline to be significant in the combined group receiving either of the two lower doses, and to result in a 76% reduction in both number and total volumes of active MRI lesions at 9 months into the study. These data provide the first indication for clinical benefit resulting from intervention in RR-MS with HspB5. Trial Registration: ClinicalTrials.gov Phase I: NCT02442557; Phase IIa: NCT02442570 PMID

  4. Multi-kW coherent combining of fiber lasers seeded with pseudo random phase modulated light

    NASA Astrophysics Data System (ADS)

    Flores, Angel; Ehrehreich, Thomas; Holten, Roger; Anderson, Brian; Dajani, Iyad

    2016-03-01

    We report efficient coherent beam combining of five kilowatt-class fiber amplifiers with a diffractive optical element (DOE). Based on a master oscillator power amplifier (MOPA) configuration, the amplifiers were seeded with pseudo random phase modulated light. Each non-polarization maintaining fiber amplifier was optically path length matched and provides approximately 1.2 kW of near diffraction-limited output power (measured M2<1.1). Consequently, a low power sample of each laser was utilized for active linear polarization control. A low power sample of the combined beam after the DOE provided an error signal for active phase locking which was performed via Locking of Optical Coherence by Single-Detector Electronic-Frequency Tagging (LOCSET). After phase stabilization, the beams were coherently combined via the 1x5 DOE. A total combined output power of 4.9 kW was achieved with 82% combining efficiency and excellent beam quality (M2<1.1). The intrinsic DOE splitter loss was 5%. Similarly, losses due in part to non-ideal polarization, ASE content, uncorrelated wavefront errors, and misalignment errors contributed to the efficiency reduction.

  5. Importance of pre-analytical steps for transcriptome and RT-qPCR analyses in the context of the phase II randomised multicentre trial REMAGUS02 of neoadjuvant chemotherapy in breast cancer patients

    PubMed Central

    2011-01-01

    Background Identification of predictive markers of response to treatment is a major objective in breast cancer. A major problem in clinical sampling is the variability of RNA templates, requiring accurate management of tumour material and subsequent analyses for future translation in clinical practice. Our aim was to establish the feasibility and reliability of high throughput RNA analysis in a prospective trial. Methods This study was conducted on RNA from initial biopsies, in a prospective trial of neoadjuvant chemotherapy in 327 patients with inoperable breast cancer. Four independent centres included patients and samples. Human U133 GeneChips plus 2.0 arrays for transcriptome analysis and quantitative RT-qPCR of 45 target genes and 6 reference genes were analysed on total RNA. Results Thirty seven samples were excluded because i) they contained less than 30% malignant cells, or ii) they provided RNA Integrity Number (RIN) of poor quality. Among the 290 remaining cases, taking into account strict quality control criteria initially defined to ensure good quality of sampling, 78% and 82% samples were eligible for transcriptome and RT-qPCR analyses, respectively. For RT-qPCR, efficiency was corrected by using standard curves for each gene and each plate. It was greater than 90% for all genes. Clustering analysis highlighted relevant breast cancer phenotypes for both techniques (ER+, PR+, HER2+, triple negative). Interestingly, clustering on trancriptome data also demonstrated a "centre effect", probably due to the sampling or extraction methods used in on of the centres. Conversely, the calibration of RT-qPCR analysis led to the centre effect withdrawing, allowing multicentre analysis of gene transcripts with high accuracy. Conclusions Our data showed that strict quality criteria for RNA integrity assessment and well calibrated and standardized RT-qPCR allows multicentre analysis of genes transcripts with high accuracy in the clinical context. More stringent

  6. Telemedicine techniques can be used to facilitate the conduct of multicentre trials.

    PubMed

    Kennedy, C; Kirwan, J; Cook, C; Roux, P; Stulting, A; Murdoch, I

    2000-01-01

    A multicentre randomized controlled trial was established in Pretoria, Bloemfontein and Edendale in South Africa, and coordinated from London. The purpose of the trial was to determine the efficacy of low-dose beta irradiation of glaucoma. Five communication modalities (telephone, fax, e-mail, videoconferencing and face-to-face meetings) were examined in terms of their benefits in a multicentre trial. The eight stages of the multicentre trial examined were: set-up and training, recruitment, standardization, patient management, data transmission, update and data dissemination, clinical follow-up and monitoring, and publication. On four-point Likert scales for rating the usefulness of the communication modalities at each of the eight stages of the trial (from 0 = not useful to 3 = very useful; maximum score 24) the telephone was given a total score of 10, fax 9, e-mail 13, videoconferencing 15 and face-to-face meetings 9. Telemedicine techniques offer considerable benefits in the coordination of multicentre trials by improving data collection, maintaining the efficacy and monitoring of trials, while potentially offering reduced costs in terms of travel and time. The realtime scrutiny of patient records helps to ensure data uniformity and completeness of data collection. Videoconferencing was most useful when considered as one of several communication tools that can be used to improve the effectiveness of a service or process. PMID:11265104

  7. Simulation study on heat conduction of a nanoscale phase-change random access memory cell.

    PubMed

    Kim, Junho; Song, Ki-Bong

    2006-11-01

    We have investigated heat transfer characteristics of a nano-scale phase-change random access memory (PRAM) cell using finite element method (FEM) simulation. Our PRAM cell is based on ternary chalcogenide alloy, Ge2Sb2Te5 (GST), which is used as a recording layer. For contact area of 100 x 100 nm2, simulations of crystallization and amorphization processes were carried out. Physical quantities such as electric conductivity, thermal conductivity, and specific heat were treated as temperature-dependent parameters. Through many simulations, it is concluded that one can reduce set current by decreasing both electric conductivities of amorphous GST and crystalline GST, and in addition to these conditions by decreasing electric conductivity of molten GST one can also reduce reset current significantly. PMID:17252792

  8. Linear response of light deformed nuclei investigated by self-consistent quasiparticle random-phase approximation

    SciTech Connect

    Losa, C.; Doessing, T.; Pastore, A.; Vigezzi, E.; Broglia, R. A.

    2010-06-15

    We present a calculation of the properties of vibrational states in deformed, axially-symmetric even-even nuclei, within the framework of a fully self-consistent quasiparticle random phase approximation (QRPA). The same Skyrme energy density and density-dependent pairing functionals are used to calculate the mean field and the residual interaction in the particle-hole and particle-particle channels. We have tested our software in the case of spherical nuclei against fully self-consistent calculations published in the literature, finding excellent agreement. We investigate the consequences of neglecting the spin-orbit and Coulomb residual interactions in QRPA. Furthermore we discuss the improvement obtained in the QRPA result associated with the removal of spurious modes. Isoscalar and isovector responses in the deformed {sup 24-26}Mg, {sup 34}Mg isotopes are presented and compared to experimental findings.

  9. Stellar electron-capture rates calculated with the finite-temperature relativistic random-phase approximation

    SciTech Connect

    Niu, Y. F.; Paar, N.; Vretenar, D.; Meng, J.

    2011-04-15

    We introduce a self-consistent microscopic theoretical framework for modeling the process of electron capture on nuclei in stellar environment, based on relativistic energy density functionals. The finite-temperature relativistic mean-field model is used to calculate the single-nucleon basis and the occupation factors in a target nucleus, and J{sup {pi}}=0{sup {+-}}, 1{sup {+-}}, and 2{sup {+-}} charge-exchange transitions are described by the self-consistent finite-temperature relativistic random-phase approximation. Cross sections and rates are calculated for electron capture on {sup 54,56}Fe and {sup 76,78}Ge in stellar environment, and results compared with predictions of similar and complementary model calculations.

  10. Canonical and microcanonical ensemble descriptions of thermal pairing within BCS and quasiparticle random-phase approximation

    SciTech Connect

    Hung, N. Quang; Dang, N. Dinh

    2010-05-15

    We propose a description of pairing properties in finite systems within the canonical and microcanonical ensembles. The approach is derived by solving the BCS and self-consistent quasiparticle random-phase approximation with the Lipkin-Nogami particle-number projection at zero temperature. The obtained eigenvalues are embedded into the canonical and microcanonical ensembles. The results obtained are found in quite good agreement with the exact solutions of the doubly-folded equidistant multilevel pairing model as well as the experimental data for {sup 56}Fe nucleus. The merit of the present approach resides in its simplicity and its application to a wider range of particle number, where the exact solution is impracticable.