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Sample records for bilateral two-step osteotomy

  1. [Single-stage bilateral Pemberton's pericapsular osteotomy in bilateral developmental dysplasia of the hip].

    Science.gov (United States)

    Zorer, Gazi; Bagatur, A Erdem

    2002-01-01

    This study was designed to evaluate the results of single-stage bilateral Pemberton's pericapsular osteotomy with or without open reduction and to demonstrate its advantages over two separate consecutive interventions in bilateral developmental dysplasia of the hip (DDH). This prospective study included 20 patients (14 girls, 6 boys; mean age 30 months; range 12 to 60 months) with bilateral DDH, who underwent single-stage bilateral Pemberton's pericapsular osteotomy with (14 patients, group A1) or without (6 patients, group A2) open reduction. Twenty patients (16 girls, 4 boys; mean age 24 months; range 13 to 47 months) with unilateral DDH, who underwent Pemberton's pericapsular osteotomy with (12 patients, group B1) or without (8 patients, group B2) open reduction were enrolled into the study as controls. Single- and two-stage procedures were compared with regard to improvement in the acetabular index, complications, mean duration of anesthesia, perioperative need for blood transfusion, length of hospital stay, initiation of walking, overall cost of antibiotic prophylaxis, and total hospital charge. There were no significant differences between A1 and B1, A2 and B2 groups with respect to mean age, gender, pre- and postoperative acetabular indices, and recovery times. However, duration of anesthesia, length of hospital stay, cost of antibiotic prophylaxis, and total hospital charges differed significantly. The amount of blood transfusion differed significantly only between groups A1 and B1. The length of hospital stay and cost of antibiotic prophylaxis in group A2 was twice as much as that of group B2. Increases in other parameters ranged between 22% to 37%. No early or late complications were encountered. Single-stage bilateral Pemberton's pericapsular osteotomy in patients with bilateral DDH seems to have significant advantages over two separate consecutive interventions. However, increased risks of bilateral osteotomies require that sufficiently equipped and

  2. Comparative Study of Skeletal Stability between Postoperative Skeletal Intermaxillary Fixation and No Skeletal Fixation after Bilateral Sagittal Split Ramus Osteotomy

    DEFF Research Database (Denmark)

    Hartlev, Jens; Godtfredsen, Erik; Andersen, Niels Trolle

    2014-01-01

    OBJECTIVES: The purpose of the present study was to evaluate skeletal stability after mandibular advancement with bilateral sagittal split osteotomy. MATERIAL AND METHODS: Twenty-six patients underwent single-jaw bilateral sagittal split osteotomy (BSSO) to correct skeletal Class II malocclusion....

  3. 3D analysis of condylar remodelling and skeletal relapse following bilateral sagittal split advancement osteotomies

    NARCIS (Netherlands)

    Xi, T.; Schreurs, R.; Loon, B. van; Koning, M.J. de; Berge, S.J.; Hoppenreijs, T.J.; Maal, T.J.J.

    2015-01-01

    A major concern in mandibular advancement surgery using bilateral sagittal split osteotomies (BSSO) is potential postoperative relapse. Although the role of postoperative changes in condylar morphology on skeletal relapse was reported in previous studies, no study so far has objectified the precise

  4. Long-term stability of anterior open-bite closure with bilateral sagittal split osteotomy.

    Science.gov (United States)

    Fontes, Adelina M; Joondeph, Donald R; Bloomquist, Dale S; Greenlee, Geoffrey M; Wallen, Terry R; Huang, Greg J

    2012-12-01

    Maxillary impaction and bimaxillary osteotomies are used to treat anterior open-bite malocclusions but can have adverse soft-tissue effects. Correcting an anterior open bite with a single mandibular procedure avoids these undesirable soft-tissue effects, but the stability of this procedure is unknown. The purpose of this study was to assess the long-term stability of anterior open-bite correction with bilateral sagittal split osteotomy and rigid internal fixation. Orthognathic surgical records of 1 oral surgeon were searched for all patients treated for anterior open bite with bilateral sagittal split osteotomy and surgical closing rotation of the mandible with rigid internal fixation. Cephalometric films from initial consultation, presurgery, postsurgery, orthodontic appliance removal, and a mean of 4.5 years after orthodontic appliance removal were collected, traced, and measured. Thirty-one patients fit the inclusion criteria for this study and had an initial mean open bite of -2.6 mm (SD, 1.1 mm). The patients experienced an average mandibular closing rotation of 3.7° (SD, 2.4°) with surgery. By orthodontic appliance removal, the mandible rotated open 1.1°, and incisor overlap was 1.4 mm (SD, 1.0 mm). Approximately 4.5 years after orthodontic appliance removal, the mean incisor overlap was maintained at 1.0 mm (SD, 1.0 mm), yet the mandible rotated open an additional 1.1°. Only 3 patients relapsed to no incisor overlap in the long term, and only 3 patients experienced relapse greater than 1 mm in the long term. Approximately 90% of the treated patients had a positive incisor overlap 4.5 years after orthodontic appliance removal. Despite a 60% loss of mandibular surgical closing rotation, only 10% of the patients relapsed to no incisor overlap in the long term. Bilateral sagittal split osteotomy and surgical closing rotation of the mandible by using rigid internal fixation should be considered a stable alternative in the treatment of mild

  5. Skeletal Stability after Large Mandibular Advancement (> 10 mm) with Bilateral Sagittal Split Osteotomy and Skeletal Elastic Intermaxillary Fixation

    DEFF Research Database (Denmark)

    Schwartz, Kristoffer; Rodrigo, Maria; Jensen, Thomas

    2016-01-01

    OBJECTIVES: The aim of the present study was to assess the skeletal stability after large mandibular advancement (> 10 mm) with bilateral sagittal split osteotomy and skeletal elastic intermaxillary fixation and to correlate the skeletal stability with the vertical facial type. MATERIAL AND METHO...

  6. Bilateral sagittal split osteotomy: Surgery first approach for correction of skeletal Class II

    Directory of Open Access Journals (Sweden)

    Revathi Peddu

    2018-01-01

    Full Text Available Most of the skeletal malocclusions which require orthognathic surgeries are treated by traditional approach which requires time-consuming and unesthetic presurgical orthodontic phase. Surgery first approach (SFA avoids these disadvantages of the traditional approach. A 24-year-old female patient with skeletal and dental class II malocclusion due to retrognathic mandible was treated with SFA. Bilateral sagittal split osteotomy with mandibular advancement was done immediately after initial alignment and closure of the existing spaces in the maxillary arch. Angle's class I molar and canine relation was achieved after surgery. Bonding of the mandibular arch was done after 1 month of orthognathic surgery and treatment was completed within 13 months. A wrap-around retainer was placed in upper arch, and bonded lingual retainer was given in the lower arch.

  7. Corrective osteotomy with retrograde Fassier-Duval nail in an osteogenesis imperfecta patient with bilateral genu valgum

    OpenAIRE

    Lin, Tsung-Yu; Yang, Chen-Yu; Liu, Shih-Chia

    2017-01-01

    Abstract Rationale: The treatment of osteogenesis imperfecta (OI) requires a multidisciplinary approach to maximize function and reduce fracture incidence. The aim of this case report was to discuss an alternative surgical approach to stabilize a corrective osteotomy using the Fassier Duval (FD) system in an OI patient. Patient concerns: A 20-year-old OI woman presented with left thigh pain, gait disturbance, and bilateral genu valgus deformities. Diagnoses: Physical examination and standing ...

  8. Propofol or midazolam infusion associated with subarachnoid anaesthesia in sheep submitted to bilateral tibial osteotomy

    Directory of Open Access Journals (Sweden)

    Marcos Paulo Antunes de Lima

    2016-09-01

    Full Text Available ABSTRACT. de Lima M.P.A., Comassetto F., Regalin D., Dallabrida A.L., Ronchi S.J. & Oleskovicz N. [Propofol or midazolam infusion associated with subarachnoid anaesthesia in sheep submitted to bilateral tibial osteotomy.] Infusão contínua de propofol ou midazolam associado à anestesia subaracnóidea em ovinos submetidos a osteotomia bilateral de tíbia. Revista Brasileira de Medicina Veterinária, 38(3:250-256, 2016. Departamento de Medicina Veteriná- ria, Centro de Ciências Agroveterinárias, Universidade do Estado de Santa Catarina, Av. Luís de Camões, 2090, Conta Dinheiro, Lages, SC 88520-000, Brasil. E-mail: noleskovicz@yahoo.com.br The sheep stands out for being a great experimental model in the orthopedic area. Thus, the aim of this study was to evaluate the safety and efficacy of the anesthetic maintenance by continuous infusion of propofol or midazolam associated with spinal anesthesia with morphine and ropivacaine in sheep underwent bilateral tibial osteotomy. Twelve healthy sheep, with an average weight of 30.5±2.7 kg were used. The animals were sedated with 0.3 mg.Kg-1 of morphine IM associated with 20 mcg.Kg-1 of detomidine IV. Then they were allocated into two groups: Midazolam group (GMID, which were induced with ketamine 5 mg.Kg-1 and midazolam 0.5 mg.Kg-1 IV, and anesthetic maintenance being performed by continuous infusion of 0 7 mg.Kg-1.h-1 of midazolam; Propofol group (GPRO, which were induced to anesthesia with 4 mg.Kg-1 propofol and maintained with its own infusion at a rate of 0.25 mg.Kg-1.min-1. The animals were intubated and maintained on spontaneous ventilation with 100% oxygen. Spinal anesthesia was performed with 0.5 mg.Kg-1 of 0.75% ropivacaine combined with 0.1 mg.Kg-1 of morphine, diluted with NaCl 0.9% solution to total volume of 1mL/7.5Kg. Significant respiratory depression after anesthesia induction was characterized by significantly increased levels of CO2 and reduced pH in both groups. A significant

  9. Premaxillary osteotomy fixation in bilateral cleft lip/palate: Introducing a new technique

    Directory of Open Access Journals (Sweden)

    Amin Rahpeyma

    2016-04-01

    Conclusion: In protruding premaxilla, osteotomy and fixation of premaxilla with miniplate to the vomer bone during alveolar bone grafting through a lip-split approach yielded satisfactory results in patients requiring secondary functional cheilorhinoplasty.

  10. Corrective osteotomy with retrograde Fassier-Duval nail in an osteogenesis imperfecta patient with bilateral genu valgum: A case report.

    Science.gov (United States)

    Lin, Tsung-Yu; Yang, Chen-Yu; Liu, Shih-Chia

    2017-11-01

    The treatment of osteogenesis imperfecta (OI) requires a multidisciplinary approach to maximize function and reduce fracture incidence. The aim of this case report was to discuss an alternative surgical approach to stabilize a corrective osteotomy using the Fassier Duval (FD) system in an OI patient. A 20-year-old OI woman presented with left thigh pain, gait disturbance, and bilateral genu valgus deformities. Physical examination and standing radiographs revealed bilateral genu valgum with previous fixation implants in the femoral and the left tibia. Staged surgery was performed. A previous Ender pin was removed from the left femur, and a FD nail was inserted in a retrograde fashion. An intercondylar fracture was encountered while inserting the female rod in the distal left femur. After removal of a previous Rush pin from the right femur, several complications were also encountered during FD nailing of the right femur. The tip threads of the FD male nail could not achieve adequate anchorage in the region of the greater trochanter. To prevent male nail dropping, a horizontal stop Kirschner pin was inserted close to the distal end of the female nail. Despite perioperative problems such as rod dropping and occurrence of an intercondylar fracture of the left distal femur, bilateral retrograde nailing using the FD system was successful. An accurate entry portal is important when performing retrograde rodding. In addition, reaming the portal to a larger diameter in order to accommodate the large head of the female nail can prevent intraoperative intercondylar split, especially when combined with an osteotomy at the distal femur. Selection of the proper surgical technique is dependent on both the surgeon's experience and the condition of the patient. Although not an optimal device, a FD nail can be used as an IM nail for corrective osteotomy at the distal femur in an adult OI patient with a small femoral IM canal. Copyright © 2017 The Authors. Published by Wolters

  11. Biomechanical Loading Evaluation of Unsintered Hydroxyapatite/poly-l-lactide Plate System in Bilateral Sagittal Split Ramus Osteotomy

    Directory of Open Access Journals (Sweden)

    Shintaro Sukegawa

    2017-07-01

    Full Text Available OSTEOTRANS MX® (Takiron Co., Ltd., Osaka, Japan is a bioactive resorbable maxillofacial osteosynthetic material composed of an unsintered hydroxyapatite/poly-l-lactide composite, and its effective osteoconductive capacity has been previously documented. However, the mechanical strength of this plate system is unclear. Thus, the aim of this in vitro study was to assess its tensile and shear strength and evaluate the biomechanical intensity of different osteosynthesis plate designs after sagittal split ramus osteotomy by simulating masticatory forces in a clinical setting. For tensile and shear strength analyses, three mechanical strength measurement samples were prepared by fixing unsintered hydroxyapatite/poly-l-lactide composed plates to polycarbonate skeletal models. Regarding biomechanical loading evaluation, 12 mandibular replicas were used and divided into four groups for sagittal split ramus osteotomy fixation. Each sample was secured in a jig and subjected to vertical load on the first molar teeth. Regarding shear strength, the novel-shaped unsintered hydroxyapatite/poly-l-lactide plate had significantly high intensity. Upon biomechanical loading evaluation, this plate system also displayed significantly high stability in addition to bioactivity, with no observed plate fracture. Thus, we have clearly demonstrated the efficacy of this plate system using an in vitro model of bilateral sagittal split ramus osteotomy of the mandible.

  12. Assessment of Soft Tissue Changes by Cephalometry and Two-Dimensional Photogrammetry in Bilateral Sagittal Split Ramus Osteotomy Cases

    Science.gov (United States)

    Martin, Alice

    2011-01-01

    ABSTRACT Objectives We aimed to compare the standard methods of cephalometry and two-dimensional photogrammetry, to evaluate the reliability and accuracy of both methods. Material and Methods Twenty-six patients (mean age 25.5, standard deviation (SD) 5.2 years) with Class II relationship and 23 patients with Class III relationship (mean age 26.4, SD 4.7 years) who had undergone bilateral sagittal split ramus osteotomy were selected, with a median follow-up of 8 months between pre- and postsurgical evaluation. Pre- and postsurgical cephalograms and lateral photograms were traced and changes were recorded. Results Pre- and postsurgical measurements of hard tissue angles and distances revealed higher correlations with cephalometrically performed soft tissue measurements of facial convexity (Class II: N-PG, r = - 0.50, P = 0.047; Class III: ANB, r = 0.73, P = 0.005; NaPg , r = 0.71, P = 0.007;) and labiomental angle (Class II: SNB, r = 0.72, P = 0.002; ANB, r = - 0.72, P = 0.002; N-B, r = - 0.68, P = 0.004; ANS-Gn, r = 0.71, P = 0.002; Class III: ANS-Gn, r = 0.65, P = 0.043) compared with two-dimensional photogrammetry. However, two-dimensional photogrammetry revealed higher correlation between lower lip length and cephalometrically assessed angular hard tissue changes (Class II: SNB, r = 0.98, P = 0.007; N-B, r = 0.89, P = 0.037; N-Pg, r = 0.90, P = 0.033; Class III: SNB, r = - 0.54, P = 0.060; NAPg, r = - 0.65, P = 0.041; N-Pg, r = 0.58, P = 0.039). Conclusions Our findings suggest that cephalometry and two-dimensional photogrammetry offer the possibility to complement one another. PMID:24421994

  13. Assessment of soft tissue changes by cephalometry and two-dimensional photogrammetry in bilateral sagittal split ramus osteotomy cases.

    Science.gov (United States)

    Rustemeyer, Jan; Martin, Alice

    2011-01-01

    We aimed to compare the standard methods of cephalometry and two-dimensional photogrammetry, to evaluate the reliability and accuracy of both methods. Twenty-six patients (mean age 25.5, standard deviation (SD) 5.2 years) with Class II relationship and 23 patients with Class III relationship (mean age 26.4, SD 4.7 years) who had undergone bilateral sagittal split ramus osteotomy were selected, with a median follow-up of 8 months between pre- and postsurgical evaluation. Pre- and postsurgical cephalograms and lateral photograms were traced and changes were recorded. Pre- and postsurgical measurements of hard tissue angles and distances revealed higher correlations with cephalometrically performed soft tissue measurements of facial convexity (Class II: N-PG, r = - 0.50, P = 0.047; Class III: ANB, r = 0.73, P = 0.005; NaPg , r = 0.71, P = 0.007;) and labiomental angle (Class II: SNB, r = 0.72, P = 0.002; ANB, r = - 0.72, P = 0.002; N-B, r = - 0.68, P = 0.004; ANS-Gn, r = 0.71, P = 0.002; Class III: ANS-Gn, r = 0.65, P = 0.043) compared with two-dimensional photogrammetry. However, two-dimensional photogrammetry revealed higher correlation between lower lip length and cephalometrically assessed angular hard tissue changes (Class II: SNB, r = 0.98, P = 0.007; N-B, r = 0.89, P = 0.037; N-Pg, r = 0.90, P = 0.033; Class III: SNB, r = - 0.54, P = 0.060; NAPg, r = - 0.65, P = 0.041; N-Pg, r = 0.58, P = 0.039). Our findings suggest that cephalometry and two-dimensional photogrammetry offer the possibility to complement one another.

  14. Assessment of Soft Tissue Changes by Cephalometry and Two-Dimensional Photogrammetry in Bilateral Sagittal Split Ramus Osteotomy Cases

    Directory of Open Access Journals (Sweden)

    Jan Rustemeyer

    2011-07-01

    Full Text Available Objectives: We aimed to compare the standard methods of cephalometry and two-dimensional photogrammetry, to evaluate the reliability and accuracy of both methods.Material and Methods: Twenty-six patients (mean age 25.5, standard deviation (SD 5.2 years with Class II relationship and 23 patients with Class III relationship (mean age 26.4, SD 4.7 years who had undergone bilateral sagittal split ramus osteotomy were selected, with a median follow-up of 8 months between pre- and postsurgical evaluation. Pre- and postsurgical cephalograms and lateral photograms were traced and changes were recorded.Results: Pre- and postsurgical measurements of hard tissue angles and distances revealed higher correlations with cephalometrically performed soft tissue measurements of facial convexity (Class II: N-PG, r = - 0.50, P = 0.047; Class III: ANB, r = 0.73, P = 0.005; NaPg , r = 0.71, P = 0.007; and labiomental angle (Class II: SNB, r = 0.72, P = 0.002; ANB, r = - 0.72, P = 0.002; N-B, r = - 0.68, P = 0.004; ANS-Gn, r = 0.71, P = 0.002; Class III: ANS-Gn, r = 0.65, P = 0.043 compared with two-dimensional photogrammetry. However, two-dimensional photogrammetry revealed higher correlation between lower lip length and cephalometrically assessed angular hard tissue changes (Class II: SNB, r = 0.98, P = 0.007; N-B, r = 0.89, P = 0.037; N-Pg, r = 0.90, P = 0.033; Class III: SNB, r = - 0.54, P = 0.060; NAPg, r = - 0.65, P = 0.041; N-Pg, r = 0.58, P = 0.039.Conclusions: Our findings suggest that cephalometry and two-dimensional photogrammetry offer the possibility to complement one another.

  15. The role of intraoperative positioning of the inferior alveolar nerve on postoperative paresthesia after bilateral sagittal split osteotomy of the mandible: prospective clinical study

    Czech Academy of Sciences Publication Activity Database

    Hanzelka, T.; Foltán, R.; Pavlíková, G.; Horká, E.; Šedý, Jiří

    2011-01-01

    Roč. 40, č. 9 (2011), s. 901-906 ISSN 0901-5027 R&D Projects: GA MŠk(CZ) LC554; GA ČR GAP304/10/0320 Grant - others:GA MŠk(CZ) 1M0538 Program:1M Institutional research plan: CEZ:AV0Z50390703 Keywords : orthognathic surgery * paresthesia * bilateral sagittal split osteotomy Subject RIV: FJ - Surgery incl. Transplants; FH - Neurology (UEM-P) Impact factor: 1.506, year: 2011

  16. Bilateral varus osteotomies in hip deformities: are early interventions superior? A long-term follow-up

    NARCIS (Netherlands)

    Haverkamp, D.; Marti, R. K.

    2007-01-01

    Coxa valga (with or withour excessive femoral anteversion) combined with acetabular dysplasia is a well-known cause of early osteoarthritis. Many authors have stated that the best result of an osteotomy can be achieved at an early stage of these osteoarthritic changes. In this study, we present 26

  17. Determination of the most appropriate stress distribution by Finite Element Analysis in fixation with resorbable screws after Bilateral Sagittal Split Ramus Osteotomy surgery

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    Sarkarat F.

    2009-12-01

    Full Text Available "nBackground and Aim: Due to the complications associated with fixation by Titanium screws and plates in Bilateral Sagittal Split Ramus Osteotomy (BSSRO surgery, the use of resorbable polymers has been increasingly recommended. Since there are not enough studies on this issue, this study aimed to assess the most appropriate stress distribution in fixation with resorbable screws after BSSRO surgery by Fnite Element Analysis (FEA."nMaterials and Methods: This experimental study was performed on simulated human mandible using Ansys and Catia softwares. The osteotomy line was applied to the simulated model and experimental loads of 75, 135 and 600 N were respectively exerted according to the natural direction of occlusal force. The distribution pattern of stress was assessed and compared for fixation with one resorbable screw, two resorbable screws in vertical pattern, two resorbable screws in horizontal pattern, three resorbable screws in L pattern and three resorbable screws in inverted backward L pattern using Ansys software."nResults: Among the four simulated fixations, L pattern showed the highest primary stability. Two screws in vertical pattern were also associated with sufficient primary stability and less trauma and cost for patients. One screw did not provide enough stability under 600 N."nConclusion: Polymer-based resorbable screws (polyglycolic acid and D, L polylactide acid provided satisfactory primary stability in BSSRO surgery.

  18. A comparison of proximal and distal Chevron osteotomy, both with lateral soft-tissue release, for moderate to severe hallux valgus in patients undergoing simultaneous bilateral correction: a prospective randomised controlled trial.

    Science.gov (United States)

    Lee, K B; Cho, N Y; Park, H W; Seon, J K; Lee, S H

    2015-02-01

    Moderate to severe hallux valgus is conventionally treated by proximal metatarsal osteotomy. Several recent studies have shown that the indications for distal metatarsal osteotomy with a distal soft-tissue procedure could be extended to include moderate to severe hallux valgus. The purpose of this prospective randomised controlled trial was to compare the outcome of proximal and distal Chevron osteotomy in patients undergoing simultaneous bilateral correction of moderate to severe hallux valgus. The original study cohort consisted of 50 female patients (100 feet). Of these, four (8 feet) were excluded for lack of adequate follow-up, leaving 46 female patients (92 feet) in the study. The mean age of the patients was 53.8 years (30.1 to 62.1) and the mean duration of follow-up 40.2 months (24.1 to 80.5). After randomisation, patients underwent a proximal Chevron osteotomy on one foot and a distal Chevron osteotomy on the other. At follow-up, the American Orthopedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal interphalangeal (MTP-IP) score, patient satisfaction, post-operative complications, hallux valgus angle, first-second intermetatarsal angle, and tibial sesamoid position were similar in each group. Both procedures gave similar good clinical and radiological outcomes. This study suggests that distal Chevron osteotomy with a distal soft-tissue procedure is as effective and reliable a means of correcting moderate to severe hallux valgus as proximal Chevron osteotomy with a distal soft-tissue procedure. ©2015 The British Editorial Society of Bone & Joint Surgery.

  19. Inicial nasal mucosa detachment using piezoelectric device in the Le Fort I osteotomy: A technical note

    OpenAIRE

    Shinohara, Elio Hitoshi; Kaba, Shajadi Carlos Pardo; Ruiz, Marcelo Martinson; Horikawa, Fernando Kendi

    2013-01-01

    In maxillary Le Fort I type osteotomy the detachment of the nasal mucosa should be done carefully. Piezoelectric surgery contributed much to increase the safety of osteotomies, despite the initial advantage of minimizing the risk of injury in nervous tissue, mainly in bilateral sagittal split osteotomy; we use the piezoelectric device for the initial detachment of the nasal mucosa in the maxillary osteotomy.

  20. A model for two-step ageing

    Indian Academy of Sciences (India)

    Unknown

    While this is true in Al–Zn–Mg alloys, two-step ageing leads to inferior properties in Al–Mg–Si alloys. This controversial behaviour in different alloys can be ... Experiments were done on AA 7010 aluminium alloy by carrying out a two-step ageing treatment and the results fit the new stability criterion. Thus it is found that the ...

  1. A model for two-step ageing

    Indian Academy of Sciences (India)

    Unknown

    matrix are not considered. In the present work, a model is developed which takes into account the coherency strains between cluster and matrix and defines a new stability criterion, inclusive of strain energy term. Experiments were done on AA 7010 aluminium alloy by carrying out a two-step ageing treatment and the.

  2. Seasat performance evaluation - The first two steps

    Science.gov (United States)

    Lame, D. B.; Born, G. H.; Dunne, J. A.; Spear, A. J.; Yamarone, C. A.

    1980-01-01

    Seasat, the satellite dedicated to the study of the oceans using microwave sensors, collected a data set containing information on sea surface winds, sea surface temperatures, wave heights, wave directions, internal waves, currents, tides, the marine geoid, and atmospheric water content. The first two steps of the performance evaluation of the satellite have been completed: (1) the engineering assessment and (2) the sensor evaluation. The results are encouraging for the performance of the instruments and the first level of data processing algorithms.

  3. Inicial nasal mucosa detachment using piezoelectric device in the Le Fort I osteotomy: A technical note

    Directory of Open Access Journals (Sweden)

    Elio Hitoshi Shinohara

    2013-01-01

    Full Text Available In maxillary Le Fort I type osteotomy the detachment of the nasal mucosa should be done carefully. Piezoelectric surgery contributed much to increase the safety of osteotomies, despite the initial advantage of minimizing the risk of injury in nervous tissue, mainly in bilateral sagittal split osteotomy; we use the piezoelectric device for the initial detachment of the nasal mucosa in the maxillary osteotomy.

  4. Inicial nasal mucosa detachment using piezoelectric device in the Le Fort I osteotomy: A technical note

    Science.gov (United States)

    Shinohara, Elio Hitoshi; Kaba, Shajadi Carlos Pardo; Ruiz, Marcelo Martinson; Horikawa, Fernando Kendi

    2013-01-01

    In maxillary Le Fort I type osteotomy the detachment of the nasal mucosa should be done carefully. Piezoelectric surgery contributed much to increase the safety of osteotomies, despite the initial advantage of minimizing the risk of injury in nervous tissue, mainly in bilateral sagittal split osteotomy; we use the piezoelectric device for the initial detachment of the nasal mucosa in the maxillary osteotomy. PMID:23853472

  5. The conditions of ADU two steps precipitation

    International Nuclear Information System (INIS)

    Li Chaoduan; Gong Xingyuan; Tang Anyuan; Duan Dezhi; Zhang Weiye

    1999-11-01

    The two steps precipitation process of ADU powder from UF 6 hydrolyzates to high active and sinterable UO 2 powder is studied. The optimized precipitation is obtained. The results indicate that the prepared ADU powder has such advantages as fine particle and active surface with higher SSA (24-30 m 2 /g) by the first step of pH value 3.0-4.0, temperature 30-40 degree C, PAM concentration 0.05 g/L. The UO 2 powder produced by such ADU has higher activity, sinterability and matrix density (≥ 96.5% T.D.)

  6. Evaluation of the accuracy of linear measurements on multi-slice and cone beam computed tomography scans to detect the mandibular canal during bilateral sagittal split osteotomy of the mandible.

    Science.gov (United States)

    Freire-Maia, B; Machado, V deC; Valerio, C S; Custódio, A L N; Manzi, F R; Junqueira, J L C

    2017-03-01

    The aim of this study was to compare the accuracy of linear measurements of the distance between the mandibular cortical bone and the mandibular canal using 64-detector multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT). It was sought to evaluate the reliability of these examinations in detecting the mandibular canal for use in bilateral sagittal split osteotomy (BSSO) planning. Eight dry human mandibles were studied. Three sites, corresponding to the lingula, the angle, and the body of the mandible, were selected. After the CT scans had been obtained, the mandibles were sectioned and the bone segments measured to obtain the actual measurements. On analysis, no statistically significant difference was found between the measurements obtained through MSCT and CBCT, or when comparing the measurements from these scans with the actual measurements. It is concluded that the images obtained by CT scan, both 64-detector multi-slice and cone beam, can be used to obtain accurate linear measurements to locate the mandibular canal for preoperative planning of BSSO. The ability to correctly locate the mandibular canal during BSSO will reduce the occurrence of neurosensory disturbances in the postoperative period. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  7. Two-step solar filament eruptions

    Science.gov (United States)

    Filippov, B.

    2018-04-01

    Coronal mass ejections (CMEs) are closely related to eruptive filaments and usually are the continuation of the same eruptive process into the upper corona. There are failed filament eruptions when a filament decelerates and stops at some greater height in the corona. Sometimes the filament after several hours starts to rise again and develops into the successful eruption with a CME formation. We propose a simple model for the interpretation of such two-step eruptions in terms of equilibrium of a flux rope in a two-scale ambient magnetic field. The eruption is caused by a slow decrease of the holding magnetic field. The presence of two critical heights for the initiation of the flux-rope vertical instability allows the flux rope to stay after the first jump some time in a metastable equilibrium near the second critical height. If the decrease of the ambient field continues, the next eruption step follows.

  8. Successful Two-step Correction for Severe Genu Valgum in Ellis-van Creveld Syndrome: A Case Report.

    Science.gov (United States)

    Kamada, Tomomi; Mashima, Naohiko; Imai, Hiroshi; Takeba, Jun; Miura, Hiromasa

    2017-01-01

    Ellis-van Creveld syndrome (EVC) is a very rare genetic disorder involving a severe, relentlessly progressive genu valgum deformity of the knee and it is usually difficult to correct all of the deformities by elevation of the depressed lateral tibial plateau alone. We are reporting one such case treated using two-step operative technique (first, gradual correction using Taylor spatial frame (TSF) and second, tibia elevation through intra-articular osteotomy). We report a case of 10-year-old female with severe genu valgum in EVC using two-step operative technique. First, performing soft tissue release and gradual correction using a TSF. Second, tibia elevation through intra-articular osteotomy resulted in improved joint congruity. At final follow-up, the patient has a good functional result and the Mikulicz line proceeded physiologically to the joint center. This two-step technique allowed for the correction of the joint architecture and associated complications are minimal. For severe genu valgum in EVC, joint congruity is improved by the elevation of the anterolateral aspect of the tibia through intra-articular osteotomy. Performing soft tissue release followed by gradual correction allows for correction of the valgus and external rotation deformities without causing neuroparalysis.

  9. Uncertainty Principles on Two Step Nilpotent Lie Groups

    Indian Academy of Sciences (India)

    Abstract. We extend an uncertainty principle due to Cowling and Price to two step nilpotent Lie groups, which generalizes a classical theorem of Hardy. We also prove an analogue of Heisenberg inequality on two step nilpotent Lie groups.

  10. Uncertainty principles on two step nilpotent Lie groups

    Indian Academy of Sciences (India)

    Abstract. We extend an uncertainty principle due to Cowling and Price to two step nilpotent Lie groups, which generalizes a classical theorem of Hardy. We also prove an analogue of Heisenberg inequality on two step nilpotent Lie groups.

  11. Tardily accelerated neurologic deterioration in two-step thallium intoxication.

    Science.gov (United States)

    Kuroda, Hiroshi; Mukai, Yoshiyuki; Nishiyama, Shuhei; Takeshita, Takayuki; Tateyama, Maki; Takeda, Atsushi; Aoki, Masashi

    2016-12-01

    Thallium intoxication was reported in cases with accidental ingestion, suicide attempt, and criminal adulteration. Reported cases were mostly one-time ingestion, therefore, the clinical course of divisional ingestion has not been fully known. Here, we report a case with two-step thallium intoxication manifesting as tardily accelerated neurologic deterioration. A 16-year-old adolescent was cryptically poisoned with thallium sulfate twice at an interval of 52days. After the first ingestion, neurologic symptoms including visual loss, myalgia, and weakness in legs developed about 40days after the development of acute gastrointestinal symptoms and alopecia. After the second ingestion, neurologic symptoms deteriorated rapidly and severely without gastrointestinal or cutaneous symptoms. Brain magnetic resonance imaging exhibited bilateral optic nerve atrophy. Nerve conduction studies revealed severe peripheral neuropathies in legs. Thallium intoxication was confirmed by an increase in urine thallium egestion. Most of the neurologic manifestations ameliorated in two years, but the visual loss persisted. The source of thallium ingestion was unraveled afterward because a murder suspect in another homicidal assault confessed the forepast adulteration. This discriminating clinical course may be attributable to the cumulative neurotoxicity due to the longer washout-time of thallium in the nervous system than other organs. It is noteworthy that the divisional thallium intoxication may manifest as progressive optic and peripheral neuropathy without gastrointestinal or cutaneous symptoms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Femoral derotation osteotomy in spastic diplegia. Proximal or distal?

    Science.gov (United States)

    Pirpiris, M; Trivett, A; Baker, R; Rodda, J; Nattrass, G R; Graham, H K

    2003-03-01

    We describe the results of a prospective study of 28 children with spastic diplegia and in-toed gait, who had bilateral femoral derotation osteotomies undertaken at either the proximal intertrochanteric or the distal supracondylar level of the femur. Preoperative clinical evaluation and three-dimensional movement analysis determined any additional soft-tissue surgery. Distal osteotomy was faster with significantly lower blood loss than proximal osteotomy. The children in the distal group achieved independent walking earlier than those in the proximal group (6.9 +/- 1.3 v 10.7 +/- 1.7 weeks; p spastic diplegia.

  13. Triple Pelvic Osteotomy and Double Pelvic Osteotomy.

    Science.gov (United States)

    Guevara, Francisco; Franklin, Samuel P

    2017-07-01

    Triple and double pelvic osteotomy (TPO, DPO) are performed with the goal of increasing acetabular ventro-version, increasing femoral head coverage, and decreasing femoral head subluxation. Since the first descriptions of TPO, there have been modifications in technique, most notably omission of the ischial osteotomy for DPO, and improvements in the implants, including availability of locking TPO/DPO bone plates. Associated complication rates seem to have declined accordingly. The most salient questions regarding these procedures remain what selection criteria should be used to identify candidates and whether halting or preventing osteoarthritis is necessary to consider these surgeries clinically beneficial. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Two Step Wittig/Dihydroxylation Synthetic Route to Higher Sugars

    DEFF Research Database (Denmark)

    Jørgensen, Morten; Madsen, Robert

    1999-01-01

    Higher carbon sugars are obtained by a two carbon, two step chain elongation of aldoses involving first a Wittig reaction and then an osmium tetroxide catalyzed dihydroxylation......Higher carbon sugars are obtained by a two carbon, two step chain elongation of aldoses involving first a Wittig reaction and then an osmium tetroxide catalyzed dihydroxylation...

  15. Two-Step Plasma Process for Cleaning Indium Bonding Bumps

    Science.gov (United States)

    Greer, Harold F.; Vasquez, Richard P.; Jones, Todd J.; Hoenk, Michael E.; Dickie, Matthew R.; Nikzad, Shouleh

    2009-01-01

    A two-step plasma process has been developed as a means of removing surface oxide layers from indium bumps used in flip-chip hybridization (bump bonding) of integrated circuits. The two-step plasma process makes it possible to remove surface indium oxide, without incurring the adverse effects of the acid etching process.

  16. Two-step stool aerobic training for smokers.

    Science.gov (United States)

    Gimenez, Manuel; Saavedra, Pedro; Martin, Nieves; Lantarón, Ev M; Polu, Elisabeth; Bach, John Robert

    2014-07-01

    The aim of this study was to analyze subjective, physical, and physiologic responses to a standardized incremental 30-min two-step stool test to create an individualized 45-min maximally intensive two-step stool endurance exercise regimen for home training. This is a longitudinal study on 26 consecutively referred male smokers aged 39-66 yrs. Each performed the two-step stool test on two 15-cm steps at 10, 20, 30, 40, 50, and 60 climbs per minute. Exertional dyspnea, oxygen consumption per unit time, ventilation, respiratory rate, tidal volume, heart rate, capillary oxyhemoglobin saturation, physiologic cost index, and oxygen pulse were recorded and compared with those observed during incremental cycle exercise (30 W per 3 mins). Multivariate analysis for each parameter was undertaken as a mixed model. All subjects attained 60 climbs per minute on the two-step stool test and performed 38-42 mins of two-step stool endurance. All parameters reached 80%-96% of cycle maximum oxygen consumption. The subjects found the two-step stool endurance simple and practical to perform at home. There were no complications. The incremental two-step stool test is a simple, cost-effective way to establish a 45-min maximally intensive endurance exercise training program practical for use in the home.

  17. Complications in bilateral mandibular distraction osteogenesis using internal devices

    NARCIS (Netherlands)

    van Strijen, P. J.; Breuning, K. H.; Becking, A. G.; Perdijk, F. B. T.; Tuinzing, D. B.

    2003-01-01

    We sought to evaluate the possibility of distraction osteogenesis as an alternative to conventional bilateral sagittal split osteotomy. Complications (intraoperative, intradistraction, and postdistraction) were evaluated retrospectively. Seventy consecutive patients (40 males and 30 females,

  18. Two-Step Incision for Periarterial Sympathectomy of the Hand.

    Science.gov (United States)

    Jeon, Seung Bae; Ahn, Hee Chang; Ahn, Yong Su; Choi, Matthew Seung Suk

    2015-11-01

    Surgical scars on the palmar surface of the hand may lead to functional and also aesthetic and psychological consequences. The objective of this study was to introduce a new incision technique for periarterial sympathectomy of the hand and to compare the results of the new two-step incision technique with those of a Koman incision by using an objective questionnaire. A total of 40 patients (17 men and 23 women) with intractable Raynaud's disease or syndrome underwent surgery in our hospital, conducted by a single surgeon, between January 2008 and January 2013. Patients who had undergone extended sympathectomy or vessel graft were excluded. Clinical evaluation of postoperative scars was performed in both groups one year after surgery using the patient and observer scar assessment scale (POSAS) and the Wake Forest University rating scale. The total patient score was 8.59 (range, 6-15) in the two-step incision group and 9.62 (range, 7-18) in the Koman incision group. A significant difference was found between the groups in the total PS score (P-value=0.034) but not in the total observer score. Our analysis found no significant difference in preoperative and postoperative Wake Forest University rating scale scores between the two-step and Koman incision groups. The time required for recovery prior to returning to work after surgery was shorter in the two-step incision group, with a mean of 29.48 days in the two-step incision group and 34.15 days in the Koman incision group (P=0.03). Compared to the Koman incision, the new two-step incision technique provides better aesthetic results, similar symptom improvement, and a reduction in the recovery time required before returning to work. Furthermore, this incision allows the surgeon to access a wide surgical field and a sufficient exposure of anatomical structures.

  19. Two-Step Incision for Periarterial Sympathectomy of the Hand

    Directory of Open Access Journals (Sweden)

    Seung Bae Jeon

    2015-11-01

    Full Text Available BackgroundSurgical scars on the palmar surface of the hand may lead to functional and also aesthetic and psychological consequences. The objective of this study was to introduce a new incision technique for periarterial sympathectomy of the hand and to compare the results of the new two-step incision technique with those of a Koman incision by using an objective questionnaire.MethodsA total of 40 patients (17 men and 23 women with intractable Raynaud's disease or syndrome underwent surgery in our hospital, conducted by a single surgeon, between January 2008 and January 2013. Patients who had undergone extended sympathectomy or vessel graft were excluded. Clinical evaluation of postoperative scars was performed in both groups one year after surgery using the patient and observer scar assessment scale (POSAS and the Wake Forest University rating scale.ResultsThe total patient score was 8.59 (range, 6-15 in the two-step incision group and 9.62 (range, 7-18 in the Koman incision group. A significant difference was found between the groups in the total PS score (P-value=0.034 but not in the total observer score. Our analysis found no significant difference in preoperative and postoperative Wake Forest University rating scale scores between the two-step and Koman incision groups. The time required for recovery prior to returning to work after surgery was shorter in the two-step incision group, with a mean of 29.48 days in the two-step incision group and 34.15 days in the Koman incision group (P=0.03.ConclusionsCompared to the Koman incision, the new two-step incision technique provides better aesthetic results, similar symptom improvement, and a reduction in the recovery time required before returning to work. Furthermore, this incision allows the surgeon to access a wide surgical field and a sufficient exposure of anatomical structures.

  20. (DNA) fragment using two-step polymerase chain reaction (PCR)

    African Journals Online (AJOL)

    Polymerase chain reaction (PCR), an essential tool in many fields such as molecular biology, normally comprises three steps: denaturation at a high temperature, annealing at a low temperature and elongation at a moderate temperature. Here, we report a two-step PCR method which incorporates annealing and elongation ...

  1. Some generalized two-step block hybrid Numerov method for ...

    African Journals Online (AJOL)

    This paper proposes a class of generalized two-step Numerov methods, a block hybrid type for the direct solution of general second order ordinary differential equations. Both the main method and additional methods were derived via interpolation and collocation procedures. The basic properties of zero stability, ...

  2. Two-step rocket engine bipropellant valve concept

    Science.gov (United States)

    Capps, J. E.; Ferguson, R. E.; Pohl, H. O.

    1969-01-01

    Initiating combustion of altitude control rocket engines in a precombustion chamber of ductile material reduces high pressure surges generated by hypergolic propellants. Two-step bipropellant valve concepts control initial propellant flow into precombustion chamber and subsequent full flow into main chamber.

  3. Midpoint two- steps rule for the square root method | Uwamusi ...

    African Journals Online (AJOL)

    We present a method “Midpoint-Two-Steps rule” for the square root functional iteration for enclosing zeros of a polynomial. The method combines classical square root method in its formulation a variant of the approach adopted by (Wang and WU,1985) where a Gauss-Siedel updating formula was used to accelerate the ...

  4. Two step culture for production of recombinant herpes simplex virus ...

    African Journals Online (AJOL)

    Herpes simplex virus type 2 (HSV-2) was the major cause of genital herpes in humans. The HSV-2 glycoprotein D (gD2) had been proved to be a potentially effective vaccine for treatment of genital herpes. The present study was to develop a two step culture to express the recombinant gD2 protein using the immobilized ...

  5. A Two-Step Approach to Analyze Satisfaction Data

    Science.gov (United States)

    Ferrari, Pier Alda; Pagani, Laura; Fiorio, Carlo V.

    2011-01-01

    In this paper a two-step procedure based on Nonlinear Principal Component Analysis (NLPCA) and Multilevel models (MLM) for the analysis of satisfaction data is proposed. The basic hypothesis is that observed ordinal variables describe different aspects of a latent continuous variable, which depends on covariates connected with individual and…

  6. Two-step two-stage fission gas release model

    International Nuclear Information System (INIS)

    Kim, Yong-soo; Lee, Chan-bock

    2006-01-01

    Based on the recent theoretical model, two-step two-stage model is developed which incorporates two stage diffusion processes, grain lattice and grain boundary diffusion, coupled with the two step burn-up factor in the low and high burn-up regime. FRAPCON-3 code and its in-pile data sets have been used for the benchmarking and validation of this model. Results reveals that its prediction is in better agreement with the experimental measurements than that by any model contained in the FRAPCON-3 code such as ANS 5.4, modified ANS5.4, and Forsberg-Massih model over whole burn-up range up to 70,000 MWd/MTU. (author)

  7. Two Step Synthesis of a Non-symmetric Acetylcholinesterase Reactivator

    Directory of Open Access Journals (Sweden)

    Vit Koleckar

    2007-08-01

    Full Text Available The newly developed and very promising acetylcholinesterase reactivator (E-1- (2-hydroxyiminomethylpyridinium-4-(4-hydroxyiminomethylpyridinium-but-2-ene dibromide was prepared using two different pathways via a two-step synthesis involving the appropriate (E-1-(4-bromobut-2-enyl-2- or 4-hydroxyiminomethyl-pyridinium bromides. Afterwards, purities and yields of the desired product prepared by both routes were compared. Finally, its potency to reactivate several nerve agent-inhibited acetylcholinesterases was tested.

  8. Modified two-step potential model: Heavy mesons | Sharma | JASSA ...

    African Journals Online (AJOL)

    Modified two-step potential model: Heavy mesons. L K Sharma, P K Jain, V R Mundembe. http://dx.doi.org/10.4314/jassa.v4i2.16898 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL ...

  9. Constructing biological pathways by a two-step counting approach.

    Directory of Open Access Journals (Sweden)

    Hsiuying Wang

    Full Text Available Networks are widely used in biology to represent the relationships between genes and gene functions. In Boolean biological models, it is mainly assumed that there are two states to represent a gene: on-state and off-state. It is typically assumed that the relationship between two genes can be characterized by two kinds of pairwise relationships: similarity and prerequisite. Many approaches have been proposed in the literature to reconstruct biological relationships. In this article, we propose a two-step method to reconstruct the biological pathway when the binary array data have measurement error. For a pair of genes in a sample, the first step of this approach is to assign counting numbers for every relationship and select the relationship with counting number greater than a threshold. The second step is to calculate the asymptotic p-values for hypotheses of possible relationships and select relationships with a large p-value. This new method has the advantages of easy calculation for the counting numbers and simple closed forms for the p-value. The simulation study and real data example show that the two-step counting method can accurately reconstruct the biological pathway and outperform the existing methods. Compared with the other existing methods, this two-step method can provide a more accurate and efficient alternative approach for reconstructing the biological network.

  10. Two-step Raman spectroscopy method for tumor diagnosis

    Science.gov (United States)

    Zakharov, V. P.; Bratchenko, I. A.; Kozlov, S. V.; Moryatov, A. A.; Myakinin, O. O.; Artemyev, D. N.

    2014-05-01

    Two-step Raman spectroscopy phase method was proposed for differential diagnosis of malignant tumor in skin and lung tissue. It includes detection of malignant tumor in healthy tissue on first step with identification of concrete cancer type on the second step. Proposed phase method analyze spectral intensity alteration in 1300-1340 and 1640-1680 cm-1 Raman bands in relation to the intensity of the 1450 cm-1 band on first step, and relative differences between RS intensities for tumor area and healthy skin closely adjacent to the lesion on the second step. It was tested more than 40 ex vivo samples of lung tissue and more than 50 in vivo skin tumors. Linear Discriminant Analysis, Quadratic Discriminant Analysis and Support Vector Machine were used for tumors type classification on phase planes. It is shown that two-step phase method allows to reach 88.9% sensitivity and 87.8% specificity for malignant melanoma diagnosis (skin cancer); 100% sensitivity and 81.5% specificity for adenocarcinoma diagnosis (lung cancer); 90.9% sensitivity and 77.8% specificity for squamous cell carcinoma diagnosis (lung cancer).

  11. Adiabatic tapered optical fiber fabrication in two step etching

    Science.gov (United States)

    Chenari, Z.; Latifi, H.; Ghamari, S.; Hashemi, R. S.; Doroodmand, F.

    2016-01-01

    A two-step etching method using HF acid and Buffered HF is proposed to fabricate adiabatic biconical optical fiber tapers. Due to the fact that the etching rate in second step is almost 3 times slower than the previous droplet etching method, terminating the fabrication process is controllable enough to achieve a desirable fiber diameter. By monitoring transmitted spectrum, final diameter and adiabaticity of tapers are deduced. Tapers with losses about 0.3 dB in air and 4.2 dB in water are produced. The biconical fiber taper fabricated using this method is used to excite whispering gallery modes (WGMs) on a microsphere surface in an aquatic environment. So that they are suitable to be used in applications like WGM biosensors.

  12. Strong Stability Preserving Two-step Runge–Kutta Methods

    KAUST Repository

    Ketcheson, David I.

    2011-12-22

    We investigate the strong stability preserving (SSP) property of two-step Runge–Kutta (TSRK) methods. We prove that all SSP TSRK methods belong to a particularly simple subclass of TSRK methods, in which stages from the previous step are not used. We derive simple order conditions for this subclass. Whereas explicit SSP Runge–Kutta methods have order at most four, we prove that explicit SSP TSRK methods have order at most eight. We present explicit TSRK methods of up to eighth order that were found by numerical search. These methods have larger SSP coefficients than any known methods of the same order of accuracy and may be implemented in a form with relatively modest storage requirements. The usefulness of the TSRK methods is demonstrated through numerical examples, including integration of very high order weighted essentially non-oscillatory discretizations.

  13. A Two Step Face Alignment Approach Using Statistical Models

    Directory of Open Access Journals (Sweden)

    Ying Cui

    2012-10-01

    Full Text Available Although face alignment using the Active Appearance Model (AAM is relatively stable, it is known to be sensitive to initial values and not robust under inconstant circumstances. In order to strengthen the ability of AAM performance for face alignment, a two step approach for face alignment combining AAM and Active Shape Model (ASM is proposed. In the first step, AAM is used to locate the inner landmarks of the face. In the second step, the extended ASM is used to locate the outer landmarks of the face under the constraint of the estimated inner landmarks by AAM. The two kinds of landmarks are then combined together to form the whole facial landmarks. The proposed approach is compared with the basic AAM and the progressive AAM methods. Experimental results show that the proposed approach gives a much more effective performance.

  14. A Novel Two-Step Hierarchial Quantitative Structure-Activity ...

    Science.gov (United States)

    Background: Accurate prediction of in vivo toxicity from in vitro testing is a challenging problem. Large public–private consortia have been formed with the goal of improving chemical safety assessment by the means of high-throughput screening. Methods and results: A database containing experimental cytotoxicity values for in vitro half-maximal inhibitory concentration (IC50) and in vivo rodent median lethal dose (LD50) for more than 300 chemicals was compiled by Zentralstelle zur Erfassung und Bewertung von Ersatz- und Ergaenzungsmethoden zum Tierversuch (ZEBET ; National Center for Documentation and Evaluation of Alternative Methods to Animal Experiments) . The application of conventional quantitative structure–activity relationship (QSAR) modeling approaches to predict mouse or rat acute LD50 values from chemical descriptors of ZEBET compounds yielded no statistically significant models. The analysis of these data showed no significant correlation between IC50 and LD50. However, a linear IC50 versus LD50 correlation could be established for a fraction of compounds. To capitalize on this observation, we developed a novel two-step modeling approach as follows. First, all chemicals are partitioned into two groups based on the relationship between IC50 and LD50 values: One group comprises compounds with linear IC50 versus LD50 relationships, and another group comprises the remaining compounds. Second, we built conventional binary classification QSAR models t

  15. Dynamics Of Innovation Diffusion With Two Step Decision Process

    Directory of Open Access Journals (Sweden)

    Szymczyk Michał

    2014-02-01

    Full Text Available The paper discusses the dynamics of innovation diffusion among heterogeneous consumers. We assume that customers’ decision making process is divided into two steps: testing the innovation and later potential adopting. Such a model setup is designed to imitate the mobile applications market. An innovation provider, to some extent, can control the innovation diffusion by two parameters: product quality and marketing activity. Using the multi-agent approach we identify factors influencing the saturation level and the speed of innovation adaptation in the artificial population. The results show that the expected level of innovation adoption among customer’s friends and relative product quality and marketing campaign intensity are crucial factors explaining them. It has to be stressed that the product quality is more important for innovation saturation level and marketing campaign has bigger influence on the speed of diffusion. The topology of social network between customers is found important, but within investigated parameter range it has lover impact on innovation diffusion dynamics than the above mentioned factors

  16. Two-Step Evolution of Endosymbiosis between Hydra and Algae

    KAUST Repository

    Ishikawa, Masakazu

    2016-07-09

    In the Hydra vulgaris group, only 2 of the 25 strains in the collection of the National Institute of Genetics in Japan currently show endosymbiosis with green algae. However, whether the other non-symbiotic strains also have the potential to harbor algae remains unknown. The endosymbiotic potential of non-symbiotic strains that can harbor algae may have been acquired before or during divergence of the strains. With the aim of understanding the evolutionary process of endosymbiosis in the H. vulgaris group, we examined the endosymbiotic potential of non-symbiotic strains of the H. vulgaris group by artificially introducing endosymbiotic algae. We found that 12 of the 23 non-symbiotic strains were able to harbor the algae until reaching the grand-offspring through the asexual reproduction by budding. Moreover, a phylogenetic analysis of mitochondrial genome sequences showed that all the strains with endosymbiotic potential grouped into a single cluster (cluster γ). This cluster contained two strains (J7 and J10) that currently harbor algae; however, these strains were not the closest relatives. These results suggest that evolution of endosymbiosis occurred in two steps; first, endosymbiotic potential was gained once in the ancestor of the cluster γ lineage; second, strains J7 and J10 obtained algae independently after the divergence of the strains. By demonstrating the evolution of the endosymbiotic potential in non-symbiotic H. vulgaris group strains, we have clearly distinguished two evolutionary steps. The step-by-step evolutionary process provides significant insight into the evolution of endosymbiosis in cnidarians.

  17. Two-step evolution of endosymbiosis between hydra and algae.

    Science.gov (United States)

    Ishikawa, Masakazu; Shimizu, Hiroshi; Nozawa, Masafumi; Ikeo, Kazuho; Gojobori, Takashi

    2016-10-01

    In the Hydra vulgaris group, only 2 of the 25 strains in the collection of the National Institute of Genetics in Japan currently show endosymbiosis with green algae. However, whether the other non-symbiotic strains also have the potential to harbor algae remains unknown. The endosymbiotic potential of non-symbiotic strains that can harbor algae may have been acquired before or during divergence of the strains. With the aim of understanding the evolutionary process of endosymbiosis in the H. vulgaris group, we examined the endosymbiotic potential of non-symbiotic strains of the H. vulgaris group by artificially introducing endosymbiotic algae. We found that 12 of the 23 non-symbiotic strains were able to harbor the algae until reaching the grand-offspring through the asexual reproduction by budding. Moreover, a phylogenetic analysis of mitochondrial genome sequences showed that all the strains with endosymbiotic potential grouped into a single cluster (cluster γ). This cluster contained two strains (J7 and J10) that currently harbor algae; however, these strains were not the closest relatives. These results suggest that evolution of endosymbiosis occurred in two steps; first, endosymbiotic potential was gained once in the ancestor of the cluster γ lineage; second, strains J7 and J10 obtained algae independently after the divergence of the strains. By demonstrating the evolution of the endosymbiotic potential in non-symbiotic H. vulgaris group strains, we have clearly distinguished two evolutionary steps. The step-by-step evolutionary process provides significant insight into the evolution of endosymbiosis in cnidarians. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Long-term evaluation of bilateral cleft lip and palate patients after early secondary closure and premaxilla repositioning.

    NARCIS (Netherlands)

    Geraedts, C.T.; Borstlap, W.A.; Groenewoud, J.M.M.; Stoelinga, P.J.W.; Borstlap-Engels, V.M.F.

    2007-01-01

    The aim of this retrospective, mixed longitudinal study was to assess the long-term outcome of early secondary closure and premaxilla osteotomy in 40 bilateral cleft lip and palate patients who underwent early secondary osteotomy of the premaxilla and bone grafting at the age of 8-12 years. Clinical

  19. Hallux varus following scarf osteotomy.

    Science.gov (United States)

    Akhtar, Shahid; Malek, Sabur; Hariharan, Kartik

    2016-12-01

    Hallux varus is an uncommon condition and majority of the cases are iatrogenic. It can occur as a result of any type of hallux valgus correction surgery and in our cases scarf osteotomy is not an exception. Treatment of this complication can be challenging and it is important to understand the factors that cause this deformity before embarking on surgical correction. Four cases of hallux varus following Scarf osteotomy (1% of our total Scarf osteotomy cases) and discuss the salient features of these patients. The authors ascertained the factors that caused iatrogenic hallux varus and formulated a classification of the nature of the deformity. The management of iatrogenic hallux varus based on our experience and proposed classification system has also been outlined and discussed. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  20. Risk factors affecting somatosensory function after sagittal split osteotomy

    DEFF Research Database (Denmark)

    Thygesen, Torben Henrik; Jensen, Allan Bardow; Helleberg, M

    2008-01-01

    Purpose The aim of this study was to evaluate potential individual and intraoperative risk factors associated with bilateral sagittal split osteotomy (BSSO) and to correlate the findings with postoperative changes in somatosensory function. Patients and Methods A total of 18 men and 29 women (mean...... correlations were noted between preoperative values for somatosensory function and changes in these variables after BSSO. Patients with low sensory thresholds before BSSO experienced more impairment than those patients with higher preoperative sensory thresholds. Conclusion These findings imply...... that somatosensory function after BSSO is dependent on both intraoperative risk factors and preoperative sensation levels....

  1. [The profile surgery. Mandibular osteotomies].

    Science.gov (United States)

    Sancho, M A; Grande, C; Parri, F J; Rivera, A; Sarget, R; Morales, L

    1996-04-01

    During the years 1987-1994, 31 mandibular osteotomies have been performed in 25 patients, 15 had mandibular alteration alone, 10 of them with prognatism, 2 with microretrognatia and 3 with chin hipoplasia. The other 10 had a combined maxillary-mandibular alteration with hipoplasia and maxillary retrussion. The preoperative work-up included cephalometric and dental study, and a cast model was done to asses the theoretical benefic of the osteotomy. All these patients underwent orthodontic treatment before and after surgery. The results have been good or very good in 96% of the cases. The ortognatic surgery offers significant aesthetic and functional improvement to these patients.

  2. Use of locking plate and screws for triple pelvic osteotomy.

    Science.gov (United States)

    Rose, Scott A; Bruecker, Ken A; Petersen, Steve W; Uddin, Nizam

    2012-01-01

    To evaluate the efficacy and complication rate associated with use of a purpose-specific locking triple pelvic osteotomy (LTPO) plate. Prospective study. Dogs (n = 9; 15 hips). Physical examination, plain film radiography, computed tomography (CT) of the pelvis, and coxofemoral arthroscopy were performed before unilateral triple pelvic osteotomy (TPO) or staged bilateral TPO. Radiographs were taken after each procedure and 3-5, 6-8, and ≥12 weeks postoperatively. Pelvic width was measured at 3 locations to evaluate pelvic canal narrowing. No screw loosening occurred. Complications occurred in only 1 hip (7%) where pullout of the locking plate-screw construct from the caudal iliac segment occurred because of a fracture of the cis-cortex; the dog made a full recovery after a salvage procedure. There was no significant reduction in the cranial pelvic width but a small reduction at the level of the acetabuli and ischiatic tuberosities was noted 3-5 weeks after the 2nd TPO. The LTPO plate was associated with a lower complication rate than previously reported for TPOs using Slocum canine pelvic osteotomy plates (CPOP) and warrants further investigation. Pullout of the caudal plate-screw construct is a complication specific to LTPO implants. Bicortical screw purchase is recommended to prevent fracture of the cis-cortex and implant pullout. © Copyright 2011 by The American College of Veterinary Surgeons.

  3. Three-Dimensional Assessment of Bilateral Symmetry of the Radius and Ulna for Planning Corrective Surgeries

    NARCIS (Netherlands)

    Vroemen, J. C.; Dobbe, J. G. G.; Jonges, R.; Strackee, S. D.; Streekstra, G. J.

    2012-01-01

    Purpose The contralateral unaffected side is often used as a reference in planning a corrective osteotomy of a malunited distal radius. Two-dimensional radiographs have proven unreliable in assessing bilateral symmetry, so we assessed 3-dimensional configurations to assess bilateral symmetry.

  4. Limb shortening osteotomy in a patient with achondroplasia and leg length difference after total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Christian L. Galata

    2013-07-01

    Full Text Available Introduction: Achondroplasia is the most common reason for disproportionate short stature. Normally, orthopedic limb lengthening procedures must be discussed in the course of this genetic disorder and have been successful in numerous achondroplastic patients in the past. In some cases, the disease may lead to leg length differences with need for surgical correction. Case Report: We report a case of achondroplastic dysplastic coxarthrosis with symptomatic leg length difference after bilateral total hip arthroplasty in a 52-year-old female patient, in which a distal femoral shortening osteotomy was successfully performed. Conclusion: Femoral shortening osteotomy is very uncommon in patients with achondroplasia. We conclude, however, that in rare cases it can be indicated and provide the advantage of shorter operation time, less perioperative complications and faster recovery compared to leg lengthening procedures. Keywords: Achondroplasia, dysplastic coxarthrosis, limb shortening, distal femur osteotomy.

  5. 48 CFR 52.214-25 - Step Two of Two-Step Sealed Bidding.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Step Two of Two-Step... Clauses 52.214-25 Step Two of Two-Step Sealed Bidding. As prescribed in 14.201-6(t), insert the following provision: Step Two of Two-Step Sealed Bidding (APR 1985) (a) This invitation for bids is issued to initiate...

  6. Calculation of the MSD two-step process with the sudden approximation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Shiro [Tohoku Univ., Sendai (Japan). Dept. of Physics; Kawano, Toshihiko [Kyushu Univ., Advanced Energy Engineering Science, Kasuga, Fukuoka (Japan)

    2000-03-01

    A calculation of the two-step process with the sudden approximation is described. The Green's function which connects the one-step matrix element to the two-step one is represented in {gamma}-space to avoid the on-energy-shell approximation. Microscopically calculated two-step cross sections are averaged together with an appropriate level density to give a two-step cross section. The calculated cross sections are compared with the experimental data, however the calculation still contains several simplifications at this moment. (author)

  7. A Two-Step Bayesian Approach for Propensity Score Analysis: Simulations and Case Study

    Science.gov (United States)

    Kaplan, David; Chen, Jianshen

    2012-01-01

    A two-step Bayesian propensity score approach is introduced that incorporates prior information in the propensity score equation and outcome equation without the problems associated with simultaneous Bayesian propensity score approaches. The corresponding variance estimators are also provided. The two-step Bayesian propensity score is provided for…

  8. Ehrenfest's theorem and the validity of the two-step model for strong-field ionization

    DEFF Research Database (Denmark)

    Shvetsov-Shilovskiy, Nikolay; Dimitrovski, Darko; Madsen, Lars Bojer

    By comparison with the solution of the time-dependent Schrodinger equation we explore the validity of the two-step semiclassical model for strong-field ionization in elliptically polarized laser pulses. We find that the discrepancy between the two-step model and the quantum theory correlates...

  9. Two-step rational cononical function in the numerical integration of ...

    African Journals Online (AJOL)

    By collocation, an explicit nonlinerar two-step scheme is obtained. Numerical examples are provided to demonstrate the performance of the scheme. The results obtained were found to be quite comparable with those by existing schemes. Key Words: Collocation two-step scheme. [Global Jnl Mathematical Sci Vol.2(1) 2003: ...

  10. Is McMurray′s osteotomy obsolete?

    Directory of Open Access Journals (Sweden)

    Phaltankar P

    1995-10-01

    Full Text Available A review of the method of performing, advantages, disadvantages of McMurray′s displacement osteotomy with regard to treatment of nonunion of transcervical fracture neck femur with viable femoral head was carried out in this study of ten cases, in view of the abandonment of the procedure in favour of angulation osteotomy. Good results obtained in the series attest to the usefulness of McMurray′s osteotomy in the difficult problem of nonunion of transcervical fracture neck femur in well selected cases with certain advantages over the angulation osteotomy due to the ′Armchair effect′.

  11. Computer assisted SCFE osteotomy planning

    International Nuclear Information System (INIS)

    Drapikowski, Pawel; Tyrakowski, Marcin; Czubak, Jaroslaw; Czwojdzinski, Adam

    2008-01-01

    Slipped capital femoral epiphysis (SCFE) is a common pediatric orthopedic disorder that requires surgical correction. Preoperative planning of a proximal femoral osteotomy is essential in cases of SCFE. This planning is usually done using 2D radiographs, but 3D data can be acquired with CT and analyzed with 3D visualization software. SCFEanalyzer is a computer program developed for preoperative planning of proximal femoral osteotomy to correct SCFE. Computed tomography scans were performed on human bone specimens: one pelvis and two femoral bones (right and left) and volume data of a patient. The CT data were used to test the abilities of the SCFEanalyzer software, which utilizes 3D virtual models of anatomic structures constructed from CT image data. Separation of anatomical bone structures is done by means of ''cutting'' 3D surface model of the pelvis. The software enables qualitative and quantitative spatial analysis of chosen parameters analogous to those done on the basis of plain radiographs. SCFEanalyzer makes it possible to evaluate the function of the hip joint by calculating the range of motion depending on the shape of bone structures based on oriented bounding box object representation. Pelvic and hip CT scans from a patient with SCFE were subjected to femoral geometry analysis and hip joint function assessment. These were done to plan and simulate osteotomy of the proximal femur. Analogous qualitative and quantitative evaluation after performing the virtual surgery were evaluated to determine the potential treatment effects. The use of computer assistance in preoperative planning enable us to increase objectivity and repeatability, and to compare the results of different types of osteotomy on the proximal femur, and thus to choose the optimal operation in each individual case. (orig.)

  12. Complications of intertrochanteric rotational osteotomy

    Energy Technology Data Exchange (ETDEWEB)

    Braunstein, E.M.; Weissman, B.N.; Sosman, J.L.; Drew, M.

    1983-11-01

    Intertrochanteric anterior rotational osteotomy is a recently developed surgical procedure to treat osteonecrosis of the femoral head. We reviewed the radiographic findings in four cases to acquaint radiologists with the usual appearance of the procedure and to assess surgical complications. In all cases, immediate postoperative radiographs showed rotation of the necrotic portion of the femoral head anteriorly so that it was no longer weight-bearing. Clinical and radiologic follow-up ranged from 12 to 30 months. In this time, three patients developed complications, including nonunion of the osteotomy, further osteonecrosis with collapse of the femoral head, and worsening pain in the absence of progressive radiologic change. Radiology provides an important means of assessing rotational osteotomy, particularly in demonstrating sufficient rotation of the femoral head to assure nonweight-bearing by diseased bone. Also, surgical complications such as nonunion and hardware loosening may be identified. Nevertheless, the patient may deteriorate clinically even in the absence of radiologic demonstration of disease pregression, and the absence of radiographic change does not assure a successful surgical outcome.

  13. Complications of intertrochanteric rotational osteotomy

    International Nuclear Information System (INIS)

    Braunstein, E.M.; Weissman, B.N.; Sosman, J.L.; Drew, M.

    1983-01-01

    Intertrochanteric anterior rotational osteotomy is a recently developed surgical procedure to treat osteonecrosis of the femoral head. We reviewed the radiographic findings in four cases to acquaint radiologists with the usual appearance of the procedure and to assess surgical complications. In all cases, immediate postoperative radiographs showed rotation of the necrotic portion of the femoral head anteriorly so that it was no longer weight-bearing. Clinical and radiologic follow-up ranged from 12 to 30 months. In this time, three patients developed complications, including nonunion of the osteotomy, further osteonecrosis with collapse of the femoral head, and worsening pain in the absence of progressive radiologic change. Radiology provides an important means of assessing rotational osteotomy, particularly in demonstrating sufficient rotation of the femoral head to assure nonweight-bearing by diseased bone. Also, surgical complications such as nonunion and hardware loosening may be identified. Nevertheless, the patient may deteriorate clinically even in the absence of radiologic demonstration of disease pregression, and the absence of radiographic change does not assure a successful surgical outcome. (orig.)

  14. Distal Metatarsal Osteotomy in Hallux Valgus Surgery: Chevron Osteotomy

    Directory of Open Access Journals (Sweden)

    Fatih Dogar

    2016-04-01

    Full Text Available Aim: Hallux valgus is a complex foot deformity resulting from medial deviation of first metatarsal and lateral deviation of toe. Radiographic and functional outcomes of chevron type distal metatarsal osteotomy applied to symptomatic hallux valgus patients with moderate deformity were assessed in the present study. Chevron osteotomy was applied to 27 feet (13 left, 14 right of 22 patients (12 women and 10 men; mean age: 45±16.7 years. Mean follow-up was 15.4± 4.71 months (range, 10%u201324. Material and Method: The average preoperative AOFAS score of 39.1 ± 8.55 (range, 32%u201357 improved (p < 0.0001 to 87.8 ± 4.7 (range, 82%u201397. The average preoperative hallux valgus angle (HVA of 37.4 ± 5.8 (range, 29%u201350 improved (p < 0.0001 to 14.8 ± 3.1 (range, 10%u201320 , and the average preoperative intermetatarsal 1-2 angle (IMA of 13.1 ± 1.5 (range, 11%u201317 improved (p < 0.0001 to 7.1 ± 1.4 (range, 5%u20139 . The average sesamoid position improved from 2.9 ± 0.2 (range, 2-3 preoperatively to 1.2 ± 0.4 (range, 1-2 (p < 0.0001. Toe hypoesthesia was developed in one patient as a complication. At the end of follow-up, patient satisfaction was found to be excellent in 16 feet (59.2% and good in 11 feet (40.8%. Results: The results of the study that chevron osteotomy yields good radiological result, high degree of postoperative patient satisfaction with minimal complications. Chevron ostoetomy is most effective method in the treatment of moderate hallux valgus.

  15. Performance enhancement of a heterojunction bipolar transistor (HBT) by two-step passivation

    International Nuclear Information System (INIS)

    Fu, S.-I.; Lai, P.-H.; Tsai, Y.-Y.; Hung, C.-W.; Yen, C.-H.; Cheng, S.-Y.; Liu, W.-C.

    2006-01-01

    An interesting two-step passivation (with ledge structure and sulphide based chemical treatment) on base surface, for the first time, is demonstrated to study the temperature-dependent DC characteristics and noise performance of an InGaP/GaAs heterojunction bipolar transistor (HBT). Improved transistor behaviors on maximum current gain β max , offset voltage ΔV CE , and emitter size effect are obtained by using the two-step passivation. Moreover, the device with the two-step passivation exhibits relatively temperature-independent and improved thermal stable performances as the temperature is increased. Therefore, the two-step passivationed device can be used for high-temperature and low-power electronics applications

  16. Investigation to biodiesel production by the two-step homogeneous base-catalyzed transesterification.

    Science.gov (United States)

    Ye, Jianchu; Tu, Song; Sha, Yong

    2010-10-01

    For the two-step transesterification biodiesel production made from the sunflower oil, based on the kinetics model of the homogeneous base-catalyzed transesterification and the liquid-liquid phase equilibrium of the transesterification product, the total methanol/oil mole ratio, the total reaction time, and the split ratios of methanol and reaction time between the two reactors in the stage of the two-step reaction are determined quantitatively. In consideration of the transesterification intermediate product, both the traditional distillation separation process and the improved separation process of the two-step reaction product are investigated in detail by means of the rigorous process simulation. In comparison with the traditional distillation process, the improved separation process of the two-step reaction product has distinct advantage in the energy duty and equipment requirement due to replacement of the costly methanol-biodiesel distillation column. Copyright 2010 Elsevier Ltd. All rights reserved.

  17. Efficient two-step testing of gene-gene interactions in genome-wide association studies.

    Science.gov (United States)

    Lewinger, Juan Pablo; Morrison, John L; Thomas, Duncan C; Murcray, Cassandra E; Conti, David V; Li, Dalin; Gauderman, W James

    2013-07-01

    Exhaustive testing of all possible SNP pairs in a genome-wide association study (GWAS) generally yields low power to detect gene-gene (G × G) interactions because of small effect sizes and stringent requirements for multiple-testing correction. We introduce a new two-step procedure for testing G × G interactions in case-control GWAS to detect interacting single nucleotide polymorphisms (SNPs) regardless of their marginal effects. In an initial screening step, all SNP pairs are tested for gene-gene association in the combined sample of cases and controls. In the second step, the pairs that pass the screening are followed up with a traditional test for G × G interaction. We show that the two-step method is substantially more powerful to detect G × G interactions than the exhaustive testing approach. For example, with 2,000 cases and 2,000 controls, the two-step method can have more than 90% power to detect an interaction odds ratio of 2.0 compared to less than 50% power for the exhaustive testing approach. Moreover, we show that a hybrid two-step approach that combines our newly proposed two-step test and the two-step test that screens for marginal effects retains the best power properties of both. The two-step procedures we introduce have the potential to uncover genetic signals that have not been previously identified in an initial single-SNP GWAS. We demonstrate the computational feasibility of the two-step G × G procedure by performing a G × G scan in the asthma GWAS of the University of Southern California Children's Health Study. © 2013 WILEY PERIODICALS, INC.

  18. Two-step chlorination: A new approach to disinfection of a primary sewage effluent.

    Science.gov (United States)

    Li, Yu; Yang, Mengting; Zhang, Xiangru; Jiang, Jingyi; Liu, Jiaqi; Yau, Cie Fu; Graham, Nigel J D; Li, Xiaoyan

    2017-01-01

    Sewage disinfection aims at inactivating pathogenic microorganisms and preventing the transmission of waterborne diseases. Chlorination is extensively applied for disinfecting sewage effluents. The objective of achieving a disinfection goal and reducing disinfectant consumption and operational costs remains a challenge in sewage treatment. In this study, we have demonstrated that, for the same chlorine dosage, a two-step addition of chlorine (two-step chlorination) was significantly more efficient in disinfecting a primary sewage effluent than a one-step addition of chlorine (one-step chlorination), and shown how the two-step chlorination was optimized with respect to time interval and dosage ratio. Two-step chlorination of the sewage effluent attained its highest disinfection efficiency at a time interval of 19 s and a dosage ratio of 5:1. Compared to one-step chlorination, two-step chlorination enhanced the disinfection efficiency by up to 0.81- or even 1.02-log for two different chlorine doses and contact times. An empirical relationship involving disinfection efficiency, time interval and dosage ratio was obtained by best fitting. Mechanisms (including a higher overall Ct value, an intensive synergistic effect, and a shorter recovery time) were proposed for the higher disinfection efficiency of two-step chlorination in the sewage effluent disinfection. Annual chlorine consumption costs in one-step and two-step chlorination of the primary sewage effluent were estimated. Compared to one-step chlorination, two-step chlorination reduced the cost by up to 16.7%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Bilateral dacryoadenitis

    Directory of Open Access Journals (Sweden)

    Charlotte Derr

    2012-01-01

    Full Text Available Acute dacryoadenitis is an uncommon condition that involves inflammation of the lacrimal gland. In rare instances, dacryoadenitis may be bilateral. A delay in proper treatment of an otherwise simple case of dacryoadenitis may lead to significant soft tissue morbidity such as cellulitis, lacrimal gland abscess, or orbital abscess. We report the case of a 24-year-old male who presented to the emergency department with acute bilateral dacryoadenitis. The patient′s symptoms did not respond to oral antibiotics and he subsequently required admission for intravenous antibiotics. During his hospitalization the patient had diagnostic testing to try to determine the etiology for his symptoms. The unique aspects of managing a case of bilateral dacryoadenitis as well as treatment recommendations are discussed in this case report.

  20. [Influence on microstructure of dental zirconia ceramics prepared by two-step sintering].

    Science.gov (United States)

    Jian, Chao; Li, Ning; Wu, Zhikai; Teng, Jing; Yan, Jiazhen

    2013-10-01

    To investigate the microstructure of dental zirconia ceramics prepared by two-step sintering. Nanostructured zirconia powder was dry compacted, cold isostatic pressed, and pre-sintered. The pre-sintered discs were cut processed into samples. Conventional sintering, single-step sintering, and two-step sintering were carried out, and density and grain size of the samples were measured. Afterward, T1 and/or T2 of two-step sintering ranges were measured. Effects on microstructure of different routes, which consisted of two-step sintering and conventional sintering were discussed. The influence of T1 and/or T2 on density and grain size were analyzed as well. The range of T1 was between 1450 degrees C and 1550 degrees C, and the range of T2 was between 1250 degrees C and 1350 degrees C. Compared with conventional sintering, finer microstructure of higher density and smaller grain could be obtained by two-step sintering. Grain growth was dependent on T1, whereas density was not much related with T1. However, density was dependent on T2, and grain size was minimally influenced. Two-step sintering could ensure a sintering body with high density and small grain, which is good for optimizing the microstructure of dental zirconia ceramics.

  1. High tibial closing wedge osteotomy for medial compartment osteoarthrosis of knee

    Directory of Open Access Journals (Sweden)

    Tuli S

    2008-01-01

    Full Text Available Background: Most patients of symptomatic osteoarthrosis of knee are associated with varus malalignment that is causative or contributory to painful arthrosis. It is rational to correct the malalignment to transfer the functional load to the unaffected or less affected compartment of the knee to relieve symptoms. We report the outcome of a simple technique of high tibial osteotomy in the medial compartment of osteoarthrosis of the knee. Materials and Methods: Between 1996 and 2004 we performed closing wedge osteotomy in 78 knees in 65 patients. The patients selected for osteotomy were symptomatic essentially due to medial compartment osteoarthrosis associated with moderate genu varum. Of the 19 patients who had bilateral symptomatic disease 11 opted for high tibial osteotomy of their second knee 1-3 years after the first operation. Preoperative grading of osteoarthrosis and postoperative function was assessed using Japanese Orthopaedic Association (JOA rating scale. Results: At a minimum follow-up of 2 years (range 2-9 years 6-10° of valgus correction at the site of osteotomy was maintained, there was significant relief of pain while walking, negotiating stairs, squatting and sitting cross-legged. Walking distance in all patients improved by two to four times their preoperative distance of 200-400 m. No patient lost any preoperative knee function. The mean JOA scoring improved from preoperative 54 (40-65 to 77 (55-85 at final follow-up. Conclusion: Closing wedge high tibial osteotomy performed by our technique can be undertaken in any setup with moderate facilities. Operation related complications are minimal and avoidable. Kirschner wire fixation is least likely to interfere with replacement surgery if it becomes necessary.

  2. Pulsed electromagnetic field treatments enhance the healing of fibular osteotomies.

    Science.gov (United States)

    Midura, Ronald J; Ibiwoye, Michael O; Powell, Kimerly A; Sakai, Yoshitada; Doehring, Todd; Grabiner, Mark D; Patterson, Thomas E; Zborowski, Maciej; Wolfman, Alan

    2005-09-01

    This study tested the hypothesis that pulsed electromagnetic field (PEMF) treatments augment and accelerate the healing of bone trauma. It utilized micro-computed tomography imaging of live rats that had received bilateral 0.2 mm fibular osteotomies (approximately 0.5% acute bone loss) as a means to assess the in vivo rate dynamics of hard callus formation and overall callus volume. Starting 5 days post-surgery, osteotomized right hind limbs were exposed 3 h daily to Physio-Stim PEMF, 7 days a week for up to 5 weeks of treatment. The contralateral hind limbs served as sham-treated, within-animal internal controls. Although both PEMF- and sham-treatment groups exhibited similar onset of hard callus at approximately 9 days after surgery, a 2-fold faster rate of hard callus formation was observed thereafter in PEMF-treated limbs, yielding a 2-fold increase in callus volume by 13-20 days after surgery. The quantity of the new woven bone tissue within the osteotomy sites was significantly better in PEMF-treated versus sham-treated fibulae as assessed via hard tissue histology. The apparent modulus of each callus was assessed via a cantilever bend test and indicated a 2-fold increase in callus stiffness in the PEMF-treated over sham-treated fibulae. PEMF-treated fibulae exhibited an apparent modulus at the end of 5-weeks that was approximately 80% that of unoperated fibulae. Overall, these data indicate that Physio-Stim PEMF treatment improved osteotomy repair. These beneficial effects on bone healing were not observed when a different PEMF waveform, Osteo-Stim, was used. This latter observation demonstrates the specificity in the relationship between waveform characteristics and biological outcomes.

  3. Biomechanical analysis of reduction malarplasty with L-shaped osteotomy.

    Science.gov (United States)

    Qiu, Shuang; Gui, Lai; Wang, Meng; Chen, Ying; Niu, Feng; Liu, Jianfeng; Liu, Wei; Zhang, Yankun

    2012-05-01

    Reduction malarplasty with L-shaped osteotomy is widely used for surgical correction of prominent zygoma and bilateral zygomatic asymmetry. One of the keys to this surgery is the formation of the greenstick fracture on the root of the zygomatic arch. However, the greenstick fracture cannot be seen directly both in the postoperative x-ray films and three-dimensional computed tomography images, and it is unknown how the greenstick fracture forms biomechanically. So it is of great concern to both the doctors and patients whether the greenstick fracture can really take place on the root of the zygomatic arch. This study focused on the biomechanism and deformation effects of the surgery by using the method of finite element (FE) analysis. Computed tomography data of 2 patients with prominent malar complex were obtained for three-dimensional reconstruction. The FE models of the zygomatic complex with L-shaped osteotomy were established by using Mimics via thresholding, segmentation techniques, and material properties assignment with gray value conversion. Then simulations including the boundary conditions and the forces of the surgery were performed in ABAQUS. The FE models have fine quality; the first one contains 63,053 units and 100,995 nodes, and the other one contains 70,238 units and 136,219 nodes. Under the loading of pressures, the zygoma and the zygomatic arch inward have deformation displacement. Maximum stress concentration was found just at the root of the zygomatic arch. A appropriate zygomatic pressure will generate a stress concentration to form the greenstick on the root of the zygomatic arch. This study can help surgeons understand and conduct the reduction malarplasty with L-shaped osteotomy from a biomechanical insight.

  4. Two-step versus Single Application of Mitomycin-C in Photorefractive Keratectomy for High Myopia

    Directory of Open Access Journals (Sweden)

    Farhad Fazel

    2012-01-01

    Full Text Available Purpose: To evaluate the long-term outcomes of two-step versus single application of mitomycin-C (MMC during photorefractive keratectomy (PRK for high myopia. Methods: This randomized clinical trial included consecutive patients with high myopia (exceeding 7 D. Patients underwent PRK and were randomized to two methods of MMC 0.02% application as follows: in the single application group, MMC was applied for 45 seconds followed by irrigation; in the two-step group MMC was used identically followed by repeat application for another 15 seconds and corneal surface irrigation. Visual acuity, refractive error, pachymetry, topography, corneal haze and complications were compared between the two groups 18 months after surgery. Results: One hundred and forty patients (70 subjects in either study arm underwent PRK according to the study protocol. Mean spherical equivalent refractive error was significantly reduced from baseline to -1.16΁0.39 D in the single application group and to -1.07΁0.39 D in the two-step group. Sixteen (11.5% versus 8 (5.7% eyes lost one or more line(s of best corrected visual acuity in the single application group as compared to the two-step group (P=0.05. Corneal haze was observed in 18 (12.9% and 8 (5.7% eyes in the single application versus two-step group, respectively (P=0.04. Grade 3 corneal haze was not observed in the two-step group but occurred in five eyes (3.6% in the single application group (P=0.03. No eyes developed corneal ectasia during the follow-up period. Conclusion: Two-step intraoperative application of MMC 0.02% in highly myopic eyes undergoing PRK can reduce the frequency and severity of haze formation.

  5. Coupling of Spinosad Fermentation and Separation Process via Two-Step Macroporous Resin Adsorption Method.

    Science.gov (United States)

    Zhao, Fanglong; Zhang, Chuanbo; Yin, Jing; Shen, Yueqi; Lu, Wenyu

    2015-08-01

    In this paper, a two-step resin adsorption technology was investigated for spinosad production and separation as follows: the first step resin addition into the fermentor at early cultivation period to decrease the timely product concentration in the broth; the second step of resin addition was used after fermentation to adsorb and extract the spinosad. Based on this, a two-step macroporous resin adsorption-membrane separation process for spinosad fermentation, separation, and purification was established. Spinosad concentration in 5-L fermentor increased by 14.45 % after adding 50 g/L macroporous at the beginning of fermentation. The established two-step macroporous resin adsorption-membrane separation process got the 95.43 % purity and 87 % yield for spinosad, which were both higher than that of the conventional crystallization of spinosad from aqueous phase that were 93.23 and 79.15 % separately. The two-step macroporous resin adsorption method has not only carried out the coupling of spinosad fermentation and separation but also increased spinosad productivity. In addition, the two-step macroporous resin adsorption-membrane separation process performs better in spinosad yield and purity.

  6. Osteotomy irrigation: is it necessary?

    Science.gov (United States)

    Flanagan, Dennis

    2010-06-01

    Surgical placement of dental implants requires an osteotomy. There is suspicion that osseous drilling may generate detrimental heat in the site that may cause localized bone necrosis and, subsequently, failure of the dental implant to osseointegrate. Cooling aqueous irrigation has been advocated to prevent such overheating. However, irrigation can interfere with operator vision and precludes bone shaving collection from the drill flukes for use in autogenous grafting. Small diameter drills may generate more heat than larger diameter drills and may need to be irrigated when smaller diameter implants are to be placed in dense bone. Contemporary larger diameter drills may not generate detrimental heat and may incrementally remove any heat damaged bone from the previous drilling. It may be safe not to use irrigation for less bone dense sites when larger diameter drills are used. In addition, higher drill force and speed may minimize osseous heating by minimizing the time of in-bone drill operation and heat generation. Irrigation to prevent bone heating during the osteotomy may not be necessary when using contemporary drill designs with an expeditious drilling technique.

  7. Triple pelvic osteotomy: effect on limb function and progression of degenerative joint disease

    International Nuclear Information System (INIS)

    Johnson, A.L.; Smith, C.W.; Pijanowski, G.J.; Hungerford, L.L.

    1998-01-01

    The objective of this study was to evaluate prospectively the outcome of 21 clinical patients treated with triple pelvic osteotomies during the year following surgery. Specific aims included documenting the time of and extent of improved limb function as measured by force plate analysis, evaluating the progression of degenerative joint disease (DJD) in the treated and untreated coxofemoral joints, and determining whether or not triple pelvic osteotomy resulted in degenerative joint changes in the ipsilateral stifle and hock. Twelve dogs were treated unilaterally and nine dogs were treated bilaterally with triple pelvic osteotomies. There were no differences in mean anteversion angles, angles of inclination, or preoperative DJD between treated hips and untreated hips. Degenerative joint disease progressed significantly in all hips regardless of treatment. Two cases developed hyperextension of their hocks after the triple pelvic osteotomies. However, no radiographic evidence of DJD was observed for any of the stifles or hocks at any observation time. A significant increase in vertical peak force (VPF) scores was noted for treated legs by two-to-three months after surgery, which continued over time. Untreated legs did not show a significant change in VPF scores over time. No differences were found in progression to higher scores when unilaterally treated legs, first-side treated legs, and second-side treated legs were compared

  8. A two-step approach improves the diagnosis of Clostridium difficile infection.

    Science.gov (United States)

    Kachrimanidou, Melina; Tegou, Zoi; Chasampalioti, Maria; Arvaniti, Kostoula; Protonotariou, Efthymia; Skoura, Lemonia

    2017-12-01

    Clostridium difficile infection (CDI) is a major cause of health care-associated diarrhea. The aim of the present study was to evaluate a two-step approach for the diagnosis of CDI. The two-step procedure consisted of GDH-toxin A/B EIA (Enzyme immunoassay targeting enterotoxin A and Cytotoxin B), followed by PCR detecting toxigenic C. difficile. Results indicate that EIAs provide a rapid screening assay for the laboratory diagnosis of CDI but, in GDH-positive and toxins-negative samples, EIA should be always followed by PCR to distinguish toxigenic vs nontoxigenic strains. GDH-toxin A/B EIA-rapid test has high specificity but low sensitivity to detect CDI. The implementation of a two-step procedure significantly increases the diagnostic accuracy to detect CDI and provides a toxigenic type characterization of C. difficile isolates. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Two-Step Estimation of Models Between Latent Classes and External Variables.

    Science.gov (United States)

    Bakk, Zsuzsa; Kuha, Jouni

    2017-11-17

    We consider models which combine latent class measurement models for categorical latent variables with structural regression models for the relationships between the latent classes and observed explanatory and response variables. We propose a two-step method of estimating such models. In its first step, the measurement model is estimated alone, and in the second step the parameters of this measurement model are held fixed when the structural model is estimated. Simulation studies and applied examples suggest that the two-step method is an attractive alternative to existing one-step and three-step methods. We derive estimated standard errors for the two-step estimates of the structural model which account for the uncertainty from both steps of the estimation, and show how the method can be implemented in existing software for latent variable modelling.

  10. Numerical calculation on a two-step subdiffusion behavior of lateral protein movement in plasma membranes

    Science.gov (United States)

    Sumi, Tomonari; Okumoto, Atsushi; Goto, Hitoshi; Sekino, Hideo

    2017-10-01

    A two-step subdiffusion behavior of lateral movement of transmembrane proteins in plasma membranes has been observed by using single-molecule experiments. A nested double-compartment model where large compartments are divided into several smaller ones has been proposed in order to explain this observation. These compartments are considered to be delimited by membrane-skeleton "fences" and membrane-protein "pickets" bound to the fences. We perform numerical simulations of a master equation using a simple two-dimensional lattice model to investigate the heterogeneous diffusion dynamics behavior of transmembrane proteins within plasma membranes. We show that the experimentally observed two-step subdiffusion process can be described using fence and picket models combined with decreased local diffusivity of transmembrane proteins in the vicinity of the pickets. This allows us to explain the two-step subdiffusion behavior without explicitly introducing nested double compartments.

  11. Bilateral agreements

    International Nuclear Information System (INIS)

    Anon.

    2004-01-01

    The bilateral agreements concern Brazil with United States relative to the co operation in nuclear energy, Germany with Russian Federation relative to the elimination and disposal of nuclear weapons; The multilateral agreements concerns the signature of the Protocols to amend the Paris and Brussels Conventions, the multilateral nuclear environmental programme in the Russian Federation, the status of Conventions in the field of nuclear energy. (N.C.)

  12. Comparison one-step procedure with two-step procedure in percutaneous nephrolithotomy.

    Science.gov (United States)

    Chen, Szu-Han; Wu, Wen-Jeng; Chou, Yii-Her; Yeh, Hsin-Chih; Tsai, Chia-Chun; Chueh, Kuang-Shun; Hou, Nien-Ting; Chiu, Siou-Jin; Tu, Hung-Pin; Li, Ching-Chia

    2014-04-01

    The aim of this study was to compare the effects of one-step percutaneous nephrolithotomy (PCNL) by the urologist alone and two-step PCNL by cooperating with the radiologist. We included 168 patients who underwent surgery by the same surgeon, 83 who underwent two-step PCNL, in which percutaneous nephrostomy insertion was performed by the radiologists on the day before endo-surgery, and 85 who underwent one-step PCNL, which involved the creation of a nephrostomy tract and performing the PCNL at the same time in the operating room, by a urologist. We compared the perioperative and postoperative parameters between these two groups. The result revealed that there were no significant differences between one-step and two-step PCNL in the decreases in haemoglobin level and blood transfusion volume, and the hospital stay was shorter in the one-step PCNL group. In addition, the one-step PCNL group was associated with significantly lower visual analogue score (VAS), which were 2.3, 1.1, and 0.4 on the post-operative days 1, 2, and 3, respectively, compared with 3.2, 1.7, and 1.0 in the two-step PCNL group. The number of parenteral analgesic prescriptions was fewer in the one-step PCNL group (0.8 ± 1.1 amps/vials) than in the two-step PCNL group (4.1 ± 2.4 amps/vials). Furthermore, different stone locations barely affected VAS and analgesic administrations. The results indicate that the one-step PCNL by the urologist alone, compared to two-step PCNL with the radiologist, has better wound pain outcome and shorter hospital stay with comparable successful rate and complication grade.

  13. Two-step retrograde closed stenting: a novel method for treating canalicular lacerations in Chinese patients.

    Science.gov (United States)

    Bi, Y; Sui, G; Zhou, Q; Heindl, L M; Bock, F; Sun, X; Tang, S; Wang, Z; Cursiefen, C

    2013-11-01

    To evaluate the efficacy of two-step retrograde closed stenting for treating canalicular laceration. methods: Forty-eight consecutive canalicular laceration cases (48 eyes) were randomised and divided into two groups: a one-step group and a two-step group. In the two-step group (23 cases), the first step was performed in the outpatient department and included identifying the medial cut end of the canaliculus and probing under a slit-lamp microscope, followed by a retrograde canalicular stenting assisted by a memory titanium stylet. The second step was canalicular anastomosis, which was performed in the operating room. In the one-step group (25 cases), all of the surgical procedures were performed when preoperative preparations were simultaneously available. The time elapsed from the doctor visit to the treatment was 4.3 ± 2.4 h in the two-step group and 18.8 ± 6.3 h in the one-step group (Ptwo-step group, and 51.4 ± 24.2 min was needed in the one-step group (Ptwo-step group and 5.4 ± 2.2 in the one-step group (Ptwo-step group and nine cases (36%) in the one-step group required other assisted methods to locate the medial cut end (P=0.007). Twenty-one cases (91.3%) in the two-step group and 20 cases (80%) in the one-step group achieved patent lacrimal drainage systems during a 12-month follow-up (P=0.528). The two-step canalicular anastomosis method allows an early search for the medial cut end of the canaliculus and improves the chances of finding it; it is also a quicker, less invasive method for treating canalicular lacerations.

  14. Ehrenfest's theorem and the validity of the two-step model for strong-field ionization

    DEFF Research Database (Denmark)

    Shvetsov-Shilovskiy, Nikolay; Dimitrovski, Darko; Madsen, Lars Bojer

    2013-01-01

    with situations where the ensemble average of the force deviates considerably from the force calculated at the average position of the trajectories of the ensemble. We identify the general trends for the applicability of the semiclassical model in terms of intensity, ellipticity, and wavelength of the laser pulse......By comparison with the solution of the time-dependent Schrödinger equation we explore the validity of the two-step semiclassical model for strong-field ionization in elliptically polarized laser pulses. We find that the discrepancy between the two-step model and the quantum theory correlates...

  15. Minimally Invasive Osteotomies of the Calcaneus.

    Science.gov (United States)

    Guyton, Gregory P

    2016-09-01

    Osteotomies of the calcaneus are powerful surgical tools, representing a critical component of the surgical reconstruction of pes planus and pes cavus deformity. Modern minimally invasive calcaneal osteotomies can be performed safely with a burr through a lateral incision. Although greater kerf is generated with the burr, the effect is modest, can be minimized, and is compatible with many fixation techniques. A hinged jig renders the procedure more reproducible and accessible. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. A modified technique for making putty-wash two-step impression

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Mishra

    2017-01-01

    Conclusion: The current article has given the options of using wax as spacer for making putty wash two step impressions for the fabrication of tooth-supported fixed restorations. Further research is required to find whether there is any dimensional inaccuracy caused in restorations due to usage of wax as a spacer.

  17. A two-step iterative method and its acceleration for outer inverses

    Indian Academy of Sciences (India)

    A two-step iterative method and its accelerated version for approximating outer inverse A2 T,S of an arbitrary matrix A are proposed. A convergence theorem for its existence is established. The rigorous error bounds are derived. Numerical experiments involving singular square, rectangular, random matrices and a sparse ...

  18. Two-step estimation procedures for inhomogeneous shot-noise Cox processes

    DEFF Research Database (Denmark)

    Prokesová, Michaela; Dvorák, Jirí; Jensen, Eva B. Vedel

    In the present paper we develop several two-step estimation procedures for inhomogeneous shot-noise Cox processes. The intensity function is parametrized by the inhomogeneity parameters while the pair-correlation function is parametrized by the interaction parameters. The suggested procedures...

  19. A two-step genetic study on quantitative precursors of coronary ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 36; Issue 5. A two-step genetic study on quantitative precursors of coronary artery disease in a homogeneous Indian population: Case–control association discovery and validation by transmission-disequilibrium test. Sanjukta Mallik Partha P Majumder. Articles Volume 36 ...

  20. Game Theory and Technical Communication: Interpreting the Texas Two-Step through Harsanyi Transformation

    Science.gov (United States)

    Williams, Miriam F.

    2012-01-01

    The author uses game theoretical models to identify technical communication breakdowns encountered during the notoriously confusing Texas Two-Step voting and caucusing process. Specifically, the author uses narrative theory and game theory to highlight areas where caucus participants needed instructions to better understand the rules of the game…

  1. Possibly All of that and Then Some: Scalar Implicatures Are Understood in Two Steps

    Science.gov (United States)

    Tomlinson, John M., Jr.; Bailey, Todd M.; Bott, Lewis

    2013-01-01

    Scalar implicatures often incur a processing cost in sentence comprehension tasks. We used a novel mouse-tracking technique in a sentence verification paradigm to test different accounts of this effect. We compared a two-step account, in which people access a basic meaning and then enrich the basic meaning to form the scalar implicature, against a…

  2. Reduced contraction stress formation obtained by a two-step cementation procedure for fiber posts

    NARCIS (Netherlands)

    Jongsma, L.A.; de Jager, N.; Kleverlaan, C.J.; Feilzer, A.J.

    2011-01-01

    Objectives In a previous study, a 60% increase in push-out strength was obtained in vitro with a two-step cementation of fiber posts, a procedure equivalent to the layering technique of composite restorations. The aim of this study is to find the rationale for this increase in push-out strength with

  3. Benefits of a two-step cementation procedure for prefabricated fiber posts

    NARCIS (Netherlands)

    Jongsma, L.A.; Bolhuis, P.B.; Pallav, P.; Feilzer, A.J.; Kleverlaan, C.J.

    2010-01-01

    Purpose: To determine whether two-step cementation of prefabricated fiber posts leads to higher bond strengths. Materials and Methods: Forty-eight human canine teeth were divided into six groups and fiber posts were cemented with DC Core, RelyX Unicem and Panavia F2.0, according to a one-step or

  4. Two Steps Forward, One Step Backward: Must This Be the Future of Diversity?

    Science.gov (United States)

    Butler, Johnnella E.

    2013-01-01

    Johnnella Butler writes here that the title of this article "Two Steps Forward, One Step Backward," expresses the "wicked problem" of diversity as a concrete goal in higher education. The concept of the "wicked problem," is a term coined in the late 1960s by social planners. Consulting Wikipedia, as so many of our…

  5. Photon strength function in the Hf-181 nucleus by method of two-step cascade

    CERN Document Server

    Le Hong Khiem

    2003-01-01

    The applicability of sum-coincidence measurements of two-step cascade gamma ray spectra determining Photon Strength Function (PSF) of Hf-181 induced from Hf-180 (n,2 gamma) Hf-181 reaction is presented. Up to 80% intensity of the primary gamma ray transitions in a wide energy range have been deduced and compared to model calculation.

  6. A Two-Step Model for Assessing Relative Interest in E-Books Compared to Print

    Science.gov (United States)

    Knowlton, Steven A.

    2016-01-01

    Librarians often wish to know whether readers in a particular discipline favor e-books or print books. Because print circulation and e-book usage statistics are not directly comparable, it can be hard to determine the relative interest of readers in the two types of books. This study demonstrates a two-step method by which librarians can assess…

  7. Two-Step, One-Pot Synthesis of Visible-Light-Responsive 6-Azopurines

    NARCIS (Netherlands)

    Kolarski, Dusan; Szymanski, Wiktor; Feringa, Ben L.

    2017-01-01

    The first general two-step, one-pot syntheticroute to 6-azopurines is presented. Microwave-assistednucleophilic aromatic substitution of protected 6-chloropurineswith hydrazines or hydrazides, followed by metal-free oxidationwith oxygen, gives 6-azopurines in high to excellent yields.Photophysical

  8. Anticipated tt-bar states in the quark-confining two-step potential model

    International Nuclear Information System (INIS)

    Kulshreshtha, D.S.

    1980-12-01

    The mass spectrum, thresholds and decay widths of the anticipated tt-bar states are studied as a function of quark mass, in a simple analytically solvable, quark-confining two-step potential model, previously used for charmonium and bottonium. (author)

  9. The cc-bar and bb-bar spectroscopy in the two-step potential model

    International Nuclear Information System (INIS)

    Kulshreshtha, D.S.; Kaiserslautern Univ.

    1984-07-01

    We investigate the spectroscopy of the charmonium (cc-bar) and bottonium (bb-bar) bound states in a static flavour independent nonrelativistic quark-antiquark (qq-bar) two-step potential model proposed earlier. Our predictions are in good agreement with experimental data and with other theoretical predictions. (author)

  10. A facile two-step dipping process based on two silica systems for a superhydrophobic surface.

    Science.gov (United States)

    Li, Xiaoguang; Shen, Jun

    2011-10-14

    A silica microsphere suspension and a silica sol are employed in a two-step dipping process for the preparation of a superhydrophobic surface. It's not only a facile way to achieve the lotus effect, but can also create a multi-functional surface with different wetabilities, adhesive forces and transparencies. This journal is © The Royal Society of Chemistry 2011

  11. Two-Step Semidefinite Programming approach to clustering and dimensionality reduction

    Directory of Open Access Journals (Sweden)

    Eloisa Macedo

    2015-08-01

    Full Text Available Inspired by the recently proposed statistical technique called clustering and disjoint principal component analysis (CDPCA, we present in this paper a new algorithm for clustering objects and dimensionality reduction, based on Semidefinite Programming (SDP models. The Two-Step-SDP algorithm is based on SDP relaxations of two clustering problems and on a K-means step in a reduced space. The Two-Step-SDP algorithm was implemented and tested in R, a widely used open source software. Besides returning clusters of both objects and attributes, the Two-Step-SDP algorithm returns the variance explained by each component and the component loadings. The numerical experiments on different data sets show that the algorithm is quite efficient and fast. Comparing to other known iterative algorithms for clustering, namely, the K-means and ALS algorithms, the computational time of the Two-Step-SDP algorithm is comparable to the K-means algorithm, and it is faster than the ALS algorithm.

  12. A sensitive trimethylamine-N-oxide aldolase assay in two steps without deproteinisation

    DEFF Research Database (Denmark)

    Nielsen, Michael Krogsgaard; Havemeister, W.; Rehbein, H.

    2000-01-01

    A two-step assay for trimethylamine-N-oxide aldolase (the target enzyme) is described in which the second step, the indicator reaction, is of the enzymatic end-point type. This indicator reaction is carried out at a slightly alkaline pH, outside the target enzyme's active pH range. An effective...

  13. A novel two-step mild hyperthermia for advanced liposomal chemotherapy.

    Science.gov (United States)

    Li, Li; ten Hagen, Timo L M; Haeri, Azadeh; Soullié, Thomas; Scholten, Csilla; Seynhaeve, Ann L B; Eggermont, Alexander M M; Koning, Gerben A

    2014-01-28

    Liposomal chemotherapy brings the advantage of minimizing systemic toxicity towards healthy organs and tissues, while has the drawbacks of limited nanoparticle accumulation and low drug bioavailability at targeted tumors. The aim of our study is to apply a clinically available mild hyperthermia (HT) treatment with thermosensitive liposomes (TSL) to tackle both issues. A two-step HT approach was combined with systemic administration of doxorubicin (Dox) TSL, in a first step to maximize nanoparticle accumulation in tumors and second step to actively trigger Dox release. The therapeutic activity of the two-step approach was compared to a one-step HT triggering intravascular Dox release from circulating TSL. Whereas the intravascular drug release approach requires fast releasing Dox-TSL (Dox-fTSL), the TSL formulation used in the two-step approach is fine-tuned to prolong Dox retention at physiological temperature in circulation, while releasing their drug content at mild HT at a slower rate (Dox-sTSL). Cytotoxicity assays show that a first-step HT at 41°C for 1h causes no drug resistance on murine BFS-1 sarcoma, human BLM melanoma cell lines and Human Umbilical Vein Endothelial Cells (HUVEC) towards subsequent exposure to Dox. However, HT sensitizes HUVEC towards Dox at higher concentrations (10-100μM). After 2h of intratumoral Dox-TSL accumulation, HT at 42°C for 1h was applied to trigger Dox release from Dox-sTSL. Quantification of intratumoral Dox accumulation revealed that the two-step HT approach increased TSL accumulation and Dox bioavailability reaching levels comparable to the intravascular release approach. The two-step HT in combination with Dox-sTSL delayed tumor growth for 12days compared to PBS group, however, was less effective compared to intravascular Dox release from Dox-fTSL using one-step HT. The two-step approach focuses on interstitial drug release upon mild HT, instead of intravascular drug release. This novel two-step approach represents an

  14. Stabilisation of sagittal split advancement osteotomies with miniplates: a prospective, multicentre study with two-year follow-up. Part II. Radiographic parameters.

    NARCIS (Netherlands)

    Borstlap, W.A.; Stoelinga, P.J.W.; Hoppenreijs, T.J.M.; Hof, M.A. van 't

    2004-01-01

    This prospective study implied a two-year follow-up on a group of patients that underwent a Bilateral Sagittal Split Osteotomy (BSSO) for advancement (n=222) of the mandible that were treated in seven institutions following the same treatment protocol. The aim of Part II of this study was to

  15. Stabilisation of sagittal split advancement osteotomies with miniplates: a prospective, multicentre study with two-year follow-up. Part I. Clinical parameters.

    NARCIS (Netherlands)

    Borstlap, W.A.; Stoelinga, P.J.W.; Hoppenreijs, T.J.M.; Hof, M.A. van 't

    2004-01-01

    The principal aim of this study was to assess the postoperative stability of bilateral sagittal split osteotomies (BSSO) using two miniplates. Part I reports on the clinical results including treatment characteristics, nerve functions, TMJ function, occlusional relapse and patient satisfaction. This

  16. Stabilisation of sagittal split advancement osteotomies with miniplates: a prospective, multicentre study with two-year follow-up. Part III--condylar remodelling and resorption.

    NARCIS (Netherlands)

    Borstlap, W.A.; Stoelinga, P.J.W.; Hoppenreijs, T.J.M.; Hof, M.A. van 't

    2004-01-01

    This prospective study implied a two-year follow-up in a group of patients that underwent a Bilateral Sagittal Split Osteotomy (BSSO) for advancement of the mandible that were treated in seven institutions following the same treatment protocol (using two miniplates). The aim of Part III of this

  17. Effectiveness of en masse versus two-step retraction: a systematic review and meta-analysis.

    Science.gov (United States)

    Rizk, Mumen Z; Mohammed, Hisham; Ismael, Omar; Bearn, David R

    2018-01-05

    This review aims to compare the effectiveness of en masse and two-step retraction methods during orthodontic space closure regarding anchorage preservation and anterior segment retraction and to assess their effect on the duration of treatment and root resorption. An electronic search for potentially eligible randomized controlled trials and prospective controlled trials was performed in five electronic databases up to July 2017. The process of study selection, data extraction, and quality assessment was performed by two reviewers independently. A narrative review is presented in addition to a quantitative synthesis of the pooled results where possible. The Cochrane risk of bias tool and the Newcastle-Ottawa Scale were used for the methodological quality assessment of the included studies. Eight studies were included in the qualitative synthesis in this review. Four studies were included in the quantitative synthesis. En masse/miniscrew combination showed a statistically significant standard mean difference regarding anchorage preservation - 2.55 mm (95% CI - 2.99 to - 2.11) and the amount of upper incisor retraction - 0.38 mm (95% CI - 0.70 to - 0.06) when compared to a two-step/conventional anchorage combination. Qualitative synthesis suggested that en masse retraction requires less time than two-step retraction with no difference in the amount of root resorption. Both en masse and two-step retraction methods are effective during the space closure phase. The en masse/miniscrew combination is superior to the two-step/conventional anchorage combination with regard to anchorage preservation and amount of retraction. Limited evidence suggests that anchorage reinforcement with a headgear produces similar results with both retraction methods. Limited evidence also suggests that en masse retraction may require less time and that no significant differences exist in the amount of root resorption between the two methods.

  18. Redo Laparoscopic Gastric Bypass: One-Step or Two-Step Procedure?

    Science.gov (United States)

    Theunissen, Caroline M J; Guelinckx, Nele; Maring, John K; Langenhoff, Barbara S

    2016-11-01

    The adjustable gastric band (AGB) is a bariatric procedure that used to be widely performed. However, AGB failure-signifying band-related complications or unsatisfactory weight loss, resulting in revision surgery (redo operations)-frequently occurs. Often this entails a conversion to a laparoscopic Roux-en-Y gastric bypass (LRYGB). This can be performed as a one-step or two-step (separate band removal) procedure. Data were collected from patients operated from 2012 to 2014 in a single bariatric centre. We compared 107 redo LRYGB after AGB failure with 1020 primary LRYGB. An analysis was performed of the one-step vs. two-step redo procedures. All redo procedures were performed by experienced bariatric surgeons. No difference in major complication rate was seen (2.8 vs. 2.3 %, p = 0.73) between redo and primary LRYGB, and overall complication severity for redos was low (mainly Clavien-Dindo 1 or 2). Weight loss results were comparable for primary and redo procedures. The one-step and two-step redos were comparable regarding complication rates and readmissions. The operating time for the one-step redo LRYGB was 136 vs. 107.5 min for the two-step (median, p step procedure is safe when performed by experienced bariatric surgeons. However, when erosion or perforation of the AGB occurs, we advise caution and would perform the redo LRYGB as a two-step procedure. Equal weights can be achieved at 1 year post redo LRYGB as after primary LRYGB procedures.

  19. Effectiveness of en masse versus two-step retraction: a systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Mumen Z. Rizk

    2018-01-01

    Full Text Available Abstract Background This review aims to compare the effectiveness of en masse and two-step retraction methods during orthodontic space closure regarding anchorage preservation and anterior segment retraction and to assess their effect on the duration of treatment and root resorption. Methods An electronic search for potentially eligible randomized controlled trials and prospective controlled trials was performed in five electronic databases up to July 2017. The process of study selection, data extraction, and quality assessment was performed by two reviewers independently. A narrative review is presented in addition to a quantitative synthesis of the pooled results where possible. The Cochrane risk of bias tool and the Newcastle-Ottawa Scale were used for the methodological quality assessment of the included studies. Results Eight studies were included in the qualitative synthesis in this review. Four studies were included in the quantitative synthesis. En masse/miniscrew combination showed a statistically significant standard mean difference regarding anchorage preservation − 2.55 mm (95% CI − 2.99 to − 2.11 and the amount of upper incisor retraction − 0.38 mm (95% CI − 0.70 to − 0.06 when compared to a two-step/conventional anchorage combination. Qualitative synthesis suggested that en masse retraction requires less time than two-step retraction with no difference in the amount of root resorption. Conclusions Both en masse and two-step retraction methods are effective during the space closure phase. The en masse/miniscrew combination is superior to the two-step/conventional anchorage combination with regard to anchorage preservation and amount of retraction. Limited evidence suggests that anchorage reinforcement with a headgear produces similar results with both retraction methods. Limited evidence also suggests that en masse retraction may require less time and that no significant differences exist in the amount of root

  20. Two-step flash light sintering of copper nanoparticle ink to remove substrate warping

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Chung-Hyeon; Joo, Sung-Jun [Department of Mechanical Convergence Engineering, Hanyang University, Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Hak-Sung, E-mail: kima@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul, 133-791 (Korea, Republic of)

    2016-10-30

    Highlights: • We performed the two-step flash light sintering for copper nanoparticle ink to remove substrate warping. • 12 J/cm{sup 2} of preheating and 7 J/cm{sup 2} of main sintering energies were determined as optimum conditions to sinter the copper nanoparticle ink. • The resistivity of two-step sintered copper nanoparticle ink was 3.81 μΩ cm with 5B adhesion level, 2.3 times greater than that of bulk copper. • The two-step sintered case showed a high conductivity without any substrate warping. - Abstract: A two-step flash light sintering process was devised to reduce the warping of polymer substrates during the sintering of copper nanoparticle ink. To determine the optimum sintering conditions of the copper nanoparticle ink, the flash light irradiation conditions (pulse power, pulse number, on-time, and off-time) were varied and optimized. In order to monitor the flash light sintering process, in situ resistance and temperature monitoring of copper nanoink were conducted during the flash light sintering process. Also, a transient heat transfer analysis was performed by using the finite-element program ABAQUS to predict the temperature changes of copper nanoink and polymer substrate. The microstructures of the sintered copper nanoink films were analyzed by scanning electron microscopy. Additionally, an X-ray diffraction and Fourier transform infrared spectroscopy were used to characterize the crystal phase change of the sintered copper nanoparticles. The resulting two-step flash light sintered copper nanoink films exhibited a low resistivity (3.81 μΩ cm, 2.3 times of that of bulk copper) and 5B level of adhesion strength without warping of the polymer substrate.

  1. 48 CFR 52.214-23 - Late submissions, modifications, revisions, and withdrawals of technical proposals under two-step...

    Science.gov (United States)

    2010-10-01

    ..., modifications, revisions, and withdrawals of technical proposals under two-step sealed bidding. 52.214-23... Late submissions, modifications, revisions, and withdrawals of technical proposals under two-step..., Modifications, Revisions, and Withdrawals of Technical Proposals Under Two-Step Sealed Bidding (NOV 1999) (a...

  2. Osteosynthesis techniques used for mandibular sagittal split osteotomy – history of orthognathic procedures and modern practice.

    Science.gov (United States)

    Nowak, Rafał; Trybek, Grzegorz

    Choosing an appropriate fixation technique after maxillary or mandibular osteotomy is one of the key factors affecting the success of orthognathic surgery. In line with the development of new surgical methods and techniques, the surgeons’ approach to the fixation of bone fragments has evolved accordingly, varying from non-fusion to different osteosynthesis techniques. Advances in medical sciences and medical technologies, have changed our attitudes to bone fragment reduction in orthopaedics and traumatology, and also in maxillofacial surgery. The pivotal underlying principle which determines bone healing – that is proper positioning so as to ensure appropriate contact area and immobilisation so as to ensure osteosynthesis – has remained unchanged for centuries. However, over the years, patient comfort and the predictability of treatment outcomes have vastly improved. The paper provides an overview of the techniques and methods used for the fixation of osteotomized fragments after bilateral sagittal split osteotomy since its introduction by Hugo Obwegeser up to the present day.

  3. A Two-Step RKC Method for Time-Dependent PDEs

    International Nuclear Information System (INIS)

    Sommeijer, Ben; Verwer, Jan

    2008-01-01

    An integration method is discussed which has been designed to treat parabolic and hyperbolic terms explicitly and stiff reaction terms implicitly. The method is a special two-step form of the one-step IMEX (IMplicit-EXplicit) RKC (Runge-Kutta-Chebyshev) method. The special two-step form is introduced with the aim of getting a non-zero imaginary stability boundary which is zero for the one-step method. Having a non-zero imaginary stability boundary allows, for example, the integration of pure advection equations space-discretized with centered schemes, the integration of damped or viscous wave equations, the integration of coupled sound and heat flow equations, etc. For our class of methods it also simplifies the choice of temporal step sizes satisfying the von Neumann stability criterion, by embedding a thin long rectangle inside the stability region.

  4. Core-shell polymer nanorods by a two-step template wetting process

    International Nuclear Information System (INIS)

    Dougherty, S; Liang, J

    2009-01-01

    One-dimensional core-shell polymer nanowires offer many advantages and great potential for many different applications. In this paper we introduce a highly versatile two-step template wetting process to fabricate two-component core-shell polymer nanowires with controllable shell thickness. PLLA and PMMA were chosen as model polymers to demonstrate the feasibility of this process. Solution wetting with different concentrations of polymer solutions was used to fabricate the shell layer and melt wetting was used to fill the shell with the core polymer. The shell thickness was analyzed as a function of the polymer solution concentration and viscosity, and the core-shell morphology was observed with TEM. This paper demonstrates the feasibility of fabricating polymer core-shell nanostructures using our two-step template wetting process and opens the arena for optimization and future experiments with polymers that are desirable for specific applications.

  5. Kalman Filtering for Discrete Stochastic Systems with Multiplicative Noises and Random Two-Step Sensor Delays

    Directory of Open Access Journals (Sweden)

    Dongyan Chen

    2015-01-01

    Full Text Available This paper is concerned with the optimal Kalman filtering problem for a class of discrete stochastic systems with multiplicative noises and random two-step sensor delays. Three Bernoulli distributed random variables with known conditional probabilities are introduced to characterize the phenomena of the random two-step sensor delays which may happen during the data transmission. By using the state augmentation approach and innovation analysis technique, an optimal Kalman filter is constructed for the augmented system in the sense of the minimum mean square error (MMSE. Subsequently, the optimal Kalman filtering is derived for corresponding augmented system in initial instants. Finally, a simulation example is provided to demonstrate the feasibility and effectiveness of the proposed filtering method.

  6. Two steps sintering alumina doped with niobia; Sinterizacao em duas etapas de alumina aditivada com niobia

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, L.B.; Hatzfeld, J.; Heck, M.; Pokorny, A.; Bergmann, C.P., E-mail: lucas.gomes@ufrgs.br [Universidade Federal do Rio Grande do Sul (LACER/UFRGS) Porto Alegre, RS (Brazil). Laboratorio de Materiais Ceramicos

    2014-07-01

    In this work, high surface area commercial alumina was doped with niobia and sintered in two steps in order to obtain dense materials with lower processing temperatures. The powders were milled and uniaxially pressed (200 MPa). The first step of sintering took place at 1100°C for 3, 6, 9 and 12 hours, followed by the second step at 1350°C for 3 hours. The relative density, porosity and water absorption of the samples were determined by the Archimedes method. The crystalline phases were analyzed by X-ray Diffraction (XRD) and the morphology of the samples after sintering, evaluated by Scanning Electron Microscopy (SEM). The results indicate that the use of niobia combined with the two steps sintering promotes an increase in the density of the material, even at lower sintering temperatures. (author)

  7. Phase-contrast diffuse optical tomography for in vivo breast imaging: a two-step method

    International Nuclear Information System (INIS)

    Jiang Ruixin; Liang Xiaoping; Zhang Qizhi; Grobmyer, Stephen; Fajardo, Laurie L.; Jiang Huabei

    2009-01-01

    We present a two-step reconstruction method that can qualitatively and quantitatively improve the reconstruction of tissue refractive index (RI) distribution by phase-contrast diffuse optical tomography (PCDOT). In this two-step method, we first recover the distribution of tissue absorption and scattering coefficients by conventional diffuse optical tomography to obtain the geometrical information of lesions, allowing the incorporation of geometrical information as a priori in the PCDOT reconstruction using a locally refined mesh. The method is validated by a series of phantom experiments and evaluated using in vivo data from 42 human subjects. The results demonstrate clear contrast of RI between the lesion and the surroundings, making the image interpretation straightforward. The sensitivity and specificity from these 42 cases are both 81% when RI is used as an imaging parameter for distinguishing between malignant and benign lesions.

  8. Simulation of vortex matter two-step melting in an anisotropic superconductor with columnar defects

    International Nuclear Information System (INIS)

    Viana, Leonardo P.; Raposo, E.P.; Coutinho-Filho, M.D.

    2006-01-01

    Columnar defects in high-temperature superconductors have been object of recent intense experimental and theoretical investigations. We report on the observation of a melting in two steps in a 3D vortex line system with randomly-placed columnar defects. We perform a Monte Carlo simulation using the Lawrence-Doniach model, with Bi 2 Sr 2 CaCu 2 O 8 parameters, in a magnetic field applied perpendicular to the CuO 2 planes and parallel to the columnar defects. The Bose glass phase observed at low temperatures melts, as the temperature increases, through two steps: first it depins to a distorted Abrikosov lattice, in which the vortex matter presents some degree of hexatic order; in the sequence, further increment in the temperature causes the fusion of this distorted lattice

  9. Stress corrosion cracking resistance of aluminum alloy 7000 series after two-step aging

    Directory of Open Access Journals (Sweden)

    Jegdić Bore V.

    2015-01-01

    Full Text Available The effect of one step-and a new (short two-step aging on the resistance to stress corrosion cracking of an aluminum alloy 7000 series was investigated, using slow strain rate test and fracture mechanics method. Aging level in the tested alloy was evaluated by means of scanning electron microscopy and measurements of electrical resistivity. It was shown that the alloy after the new two-step aging is significantly more resistant to stress corrosion cracking. Values of tensile properties and fracture toughness are similar for both thermal states. Processes that take place at the crack tip have been considered. The effect of the testing solution temperature on the crack growth rate on the plateau was determined. Two values of the apparent activation energy were obtained. These values correspond to different processes that control crack growth rate on the plateau at higher and lower temperatures. [Projekat Ministarstva nauke Republike Srbije, br. TR 34028 i br. TR 34016

  10. Effectiveness of a two-step population-based osteoporosis screening program using FRAX

    DEFF Research Database (Denmark)

    Rubin, K H; Rothmann, M J; Holmberg, T

    2018-01-01

    The Risk-stratified Osteoporosis Strategy Evaluation (ROSE) study investigated the effectiveness of a two-step screening program for osteoporosis in women. We found no overall reduction in fractures from systematic screening compared to the current case-finding strategy. The group of moderate......- to high-risk women, who accepted the invitation to DXA, seemed to benefit from the program. INTRODUCTION: The purpose of the ROSE study was to investigate the effectiveness of a two-step population-based osteoporosis screening program using the Fracture Risk Assessment Tool (FRAX) derived from a self......-administered questionnaire to select women for DXA scan. After the scanning, standard osteoporosis management according to Danish national guidelines was followed. METHODS: Participants were randomized to either screening or control group, and randomization was stratified according to age and area of residence. Inclusion...

  11. Information search behaviour among new car buyers: A two-step cluster analysis

    Directory of Open Access Journals (Sweden)

    S.M. Satish

    2010-03-01

    Full Text Available A two-step cluster analysis of new car buyers in India was performed to identify taxonomies of search behaviour using personality and situational variables, apart from sources of information. Four distinct groups were found—broad moderate searchers, intense heavy searchers, low broad searchers, and low searchers. Dealers can identify the members of each segment by measuring the variables used for clustering, and can then design appropriate communication strategies.

  12. Two-step resonance ionization spectroscopy of Na atomic beam using cw and pulsed lasers

    International Nuclear Information System (INIS)

    Katsuragawa, H.; Minowa, T.; Shimazu, M.

    1988-01-01

    Two-step photoionization of sodium atomic beam has been carried out using a cw and a pulsed dye lasers. Sodium ions have been detected by a time of flight method in order to reduce background noise. With a proper power of the pulsed dye laser the sodium atomic beam has been irradiated by a resonant cw dye laser. The density of the sodium atomic beam is estimated to be 10 3 cm -3 at the ionization area. (author)

  13. A two-step scheme for the advection equation with minimized dissipation and dispersion errors

    Science.gov (United States)

    Takacs, L. L.

    1985-01-01

    A two-step advection scheme of the Lax-Wendroff type is derived which has accuracy and phase characteristics similar to that of a third-order scheme. The scheme is exactly third-order accurate in time and space for uniform flow. The new scheme is compared with other currently used methods, and is shown to simulate well the advection of localized disturbances with steep gradients. The scheme is derived for constant flow and generalized to two-dimensional nonuniform flow.

  14. Improving accuracy of rare variant imputation with a two-step imputation approach

    DEFF Research Database (Denmark)

    Kreiner-Møller, Eskil; Medina-Gomez, Carolina; Uitterlinden, André G

    2015-01-01

    not being comprehensively scrutinized. Next-generation arrays ensuring sufficient coverage together with new reference panels, as the 1000 Genomes panel, are emerging to facilitate imputation of low frequent single-nucleotide polymorphisms (minor allele frequency (MAF) two-step......, the concordance rate between calls of imputed and true genotypes was found to be significantly higher for heterozygotes (Ptwo-step approach in our setting improves imputation quality compared with traditional direct imputation noteworthy...

  15. Variational description of the positive column with two-step ionization

    Science.gov (United States)

    Crawford, F. W.

    1980-01-01

    The ionization balance in diffusion-dominated discharges may depend on both one- and two-step ionization processes. The Spenke diffusion equation describing such conditions is solved in this paper by the Rayleigh-Ritz variational method. Simple analytic approximations to the density profile, and the similarity relation between the equation parameter, and the discharge dimensions, are derived for planar and cylindrical geometry and compared with exact computations for certain limiting cases.

  16. ONE-STEP AND TWO-STEP CALIBRATION OF A PORTABLE PANORAMIC IMAGE MAPPING SYSTEM

    Directory of Open Access Journals (Sweden)

    P.-C. Wang

    2012-07-01

    Full Text Available A Portable Panoramic Image Mapping System (PPIMS is proposed for rapid acquisition of three-dimensional spatial information. By considering the convenience of use, cost, weight of equipment, precision, and power supply, the designed PPIMS is equipped with 6 circularly arranged cameras to capture panoramic images and a GPS receiver for positioning. The motivation for this design is to develop a hand-held Mobile Mapping System (MMS for some difficult accessing areas by vehicle MMS, such as rugged terrains, forest areas, heavily damaged disaster areas, and crowed places etc. This PPIMS is in fact a GPS assisted close-range photogrammetric system. Compared with the traditional close-range photogrammetry, PPIMS can reduce the need of ground control points significantly. Under the condition of knowing the relative geometric relationships of the equipped sensors, the elements of exterior orientation of each captured image can be solved. However, the procedure of a system calibration should be done accurately to determine the relative geometric relationships of multi-cameras and the GPS antenna center, before the PPIMS can be applied for geo-referenced mapping. In this paper, both of one-step and two-step calibration procedures for PPIMS are performed to determine the lever-arm offsets and boresight angles among cameras and GPS. The performance of the one-step and two-step calibration is evaluated through the analysis of the experimental results. The comparison between these two calibration procedures was also conducted. The two-step calibration method outperforms the one-step calibration method in terms of calibration accuracy and operation convenience. We expect that the proposed two-step calibration procedure can also be applied to other platform-based MMSs.

  17. Tranfusion risk: is "two-step" vaginal delivery a risk for postpartum hemorrhage?

    Science.gov (United States)

    Straface, Gianluca; Bassi, Emma; De Santis, Marco; Scambia, Giovanni; Zanardo, Vincenzo

    2015-01-01

    In the active management strategy of third stage of labor, the optimal timing for clamping the umbilical cord after birth has been a subject of controversy. We want to evaluate if "two-step" delivery is a risk factor for postpartum hemorrhage (PPH), defined as need of transfusion, comparing to operative delivery, elective caesarean delivery and emergency caesarean delivery. This is a retrospective cohort study conducted in division of Perinatal Medicine, Policlinico Abano Terme. We evaluated the need of transfusion in all cases of PPH verified in all single deliveries between January 2011 and December 2012. The main outcome measure was blood loss and red blood cell transfusion. We found 17 cases of PPH (0.88%). The distribution of PPH in relation to mode of delivery was 0.71%, 2.46% and 1.98% respectively for two-step vaginal delivery (RR = 0.81 (0.56-1.22)), emergency cesarean section (RR = 2.88 (1.27-7.77)) and operative vaginal delivery (RR = 2.88 (0.59-5.66)). In labor induction there is a stronger relative risk association between PPH and as emergency cesarean delivery (p < 0.05) as operative vaginal delivery (p < 0.05). "Two-step" delivery approach did not increase the risk of PPH with respect to operative delivery, elective caesarean section and emergency caesarean section.

  18. A two-step filtering-based iterative image reconstruction method for interior tomography.

    Science.gov (United States)

    Zhang, Hanming; Li, Lei; Yan, Bin; Wang, Linyuan; Cai, Ailong; Hu, Guoen

    2016-10-06

    The optimization-based method that utilizes the additional sparse prior of region-of-interest (ROI) image, such as total variation, has been the subject of considerable research in problems of interior tomography reconstruction. One challenge for optimization-based iterative ROI image reconstruction is to build the relationship between ROI image and truncated projection data. When the reconstruction support region is smaller than the original object, an unsuitable representation of data fidelity may lead to bright truncation artifacts in the boundary region of field of view. In this work, we aim to develop an iterative reconstruction method to suppress the truncation artifacts and improve the image quality for direct ROI image reconstruction. A novel reconstruction approach is proposed based on an optimization problem involving a two-step filtering-based data fidelity. Data filtering is achieved in two steps: the first takes the derivative of projection data; in the second step, Hilbert filtering is applied in the differentiated data. Numerical simulations and real data reconstructions have been conducted to validate the new reconstruction method. Both qualitative and quantitative results indicate that, as theoretically expected, the proposed method brings reasonable performance in suppressing truncation artifacts and preserving detailed features. The presented local reconstruction method based on the two-step filtering strategy provides a simple and efficient approach for the iterative reconstruction from truncated projections.

  19. Normal Range of Head-to-body Delivery Interval by Two-step Delivery.

    Science.gov (United States)

    Zhang, Hong-Yu; Guo, Ren-Fei; Wu, Yan; Ling, Yi

    2016-05-05

    The one-step method was routine practices in China, scientific evidence to support this intervention is scarce. The purpose of this study was to observe the natural process of head-to-body delivery interval by waiting for at least one contraction (two-step) after head delivered in normal birth. From March 1 to March 30 in 2015 at Haikou Maternal and Child Hospital in China, normal vaginal birth with normal baby condition were recorded by video. Videotapes were transferred to computer then replayed and observed. Ninety-two cases were enrolled in this study. The average head-to-body delivery interval by two-step delivery was 71.04 ± 61.02 s, (mean + 2 standard deviation = 193.07 s, 95% confidence interval [15.65-229.15] s). Fifty-one patients (51/92, 55.43%) were two-step delivery. Majority shoulders were delivered at the first contraction. Majority shoulders emerged from perineum rather from under pubic arch. The routine one-step method of shoulder delivery where the downward force applied is not necessary and is not the right direction. Baby's breath, making faces, sucking, bubble from noses and mouth, and the light blue color of the faces, all those signs during shoulder delivery indicated a normal live birth.

  20. A two-step method for rapid characterization of electroosmotic flows in capillary electrophoresis.

    Science.gov (United States)

    Zhang, Wenjing; He, Muyi; Yuan, Tao; Xu, Wei

    2017-12-01

    The measurement of electroosmotic flow (EOF) is important in a capillary electrophoresis (CE) experiment in terms of performance optimization and stability improvement. Although several methods exist, there are demanding needs to accurately characterize ultra-low electroosmotic flow rates (EOF rates), such as in coated capillaries used in protein separations. In this work, a new method, called the two-step method, was developed to accurately and rapidly measure EOF rates in a capillary, especially for measuring the ultra-low EOF rates in coated capillaries. In this two-step method, the EOF rates were calculated by measuring the migration time difference of a neutral marker in two consecutive experiments, in which a pressure driven was introduced to accelerate the migration and the DC voltage was reversed to switch the EOF direction. Uncoated capillaries were first characterized by both this two-step method and a conventional method to confirm the validity of this new method. Then this new method was applied in the study of coated capillaries. Results show that this new method is not only fast in speed, but also better in accuracy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Two-step procedure for complicated appendicitis with perityphlitic abscess formation.

    Science.gov (United States)

    Miftaroski, Almir; Kessler, Ulf; Monnard, Etienne; Egger, Bernhard

    2017-04-19

    Optimal management of perforated appendicitis with perityphlitic phlegmon or abscess formation is controversial. The aim of the study was to assess the outcome after a two-step procedure to treat patients with perityphlitic abscess formation. We retrospectively assessed prospectively collected data from a single-centre database that included adult patients who had appendicitis and perityphlitic abscess (>=3 cm) but no generalised peritonitis, and were treated in 2007-2015. Patients underwent a two-step procedure that comprised antibiotic treatment and drainage when technically feasible (step 1) followed by interval appendectomy (step 2). We evaluated treatment modalities, complications and outcomes. Out of a total of 1480 patients with appendicitis, 15 patients presented with perityphlitic abscess. In addition to antibiotic treatment, computed tomography-guided drainage was performed in 12 of these cases. Step 1 and 2 hospital stays were (median, range) 7 days (5–14 days) and 2 days (2–12 days), respectively. One patient’s abscess recurred after 2 months, associated with new onset appendicitis and perforation. Another patient underwent reoperation after interval appendectomy for suspected postoperative peritonitis. This two-step procedure for appendicitis with appendicular abscess was highly successful (100%) with a low rate of complications (13%). In the view of a potentially increased rate of appendicular neoplasm in combination with abscess formation, the role of interval appendectomy has to be evaluated in larger trials.

  2. A new methodology to determine kinetic parameters for one- and two-step chemical models

    Science.gov (United States)

    Mantel, T.; Egolfopoulos, F. N.; Bowman, C. T.

    1996-01-01

    In this paper, a new methodology to determine kinetic parameters for simple chemical models and simple transport properties classically used in DNS of premixed combustion is presented. First, a one-dimensional code is utilized to performed steady unstrained laminar methane-air flame in order to verify intrinsic features of laminar flames such as burning velocity and temperature and concentration profiles. Second, the flame response to steady and unsteady strain in the opposed jet configuration is numerically investigated. It appears that for a well determined set of parameters, one- and two-step mechanisms reproduce the extinction limit of a laminar flame submitted to a steady strain. Computations with the GRI-mech mechanism (177 reactions, 39 species) and multicomponent transport properties are used to validate these simplified models. A sensitivity analysis of the preferential diffusion of heat and reactants when the Lewis number is close to unity indicates that the response of the flame to an oscillating strain is very sensitive to this number. As an application of this methodology, the interaction between a two-dimensional vortex pair and a premixed laminar flame is performed by Direct Numerical Simulation (DNS) using the one- and two-step mechanisms. Comparison with the experimental results of Samaniego et al. (1994) shows a significant improvement in the description of the interaction when the two-step model is used.

  3. Two-step LASIK with topography-guided ablation to correct astigmatism after penetrating keratoplasty.

    Science.gov (United States)

    Mularoni, Alessandro; Laffi, Gian Luca; Bassein, Leona; Tassinari, Giorgio

    2006-01-01

    To assess the efficacy, predictability, stability, and safety of a two-step LASIK procedure using topography-guided ablation to correct astigmatism after penetrating keratoplasty. Fifteen eyes of 15 patients underwent a two-step LASIK procedure at the Maggiore Hospital of Bologna, Italy. In the first step, a flap was created using the Hansatome microkeratome. In the second step, topography-guided ablation using the LaserSight LSX was planned with interactive software (CIPTA) once topographical and refractive stabilization had been obtained. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cylindrical correction, gain of lines of BSCVA, spherical equivalent refraction, and complications were analyzed. Minimum follow-up was 12 months (range: 12 to 30 months). Uncorrected visual acuity improved in all 15 (100%) eyes. At the last postoperative examination, 11 (73%) eyes had UCVA > or = 20/40. Nine (60%) eyes were within 1.0 diopter (D) of the attempted correction. Mean postoperative astigmatism was -1.67 (range: -3.5 to 0; standard deviation: 1.26). Index of success of astigmatic correction was 0.26. No patient lost Snellen lines of BSCVA. Intraoperative complications included two buttonhole flaps, and postoperative complications included one flap retraction. No further laser treatment was needed. The two-step LASIK procedure using topography-guided ablation reduces spherical and cylindrical refractive error due to penetrating keratoplasty. Topography-guided ablation also proved to be effective in correcting irregular astigmatism.

  4. Effect of two-step aging on the mechanical properties of AA2219 DC cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Elgallad, E.M., E-mail: eelgalla@uqac.ca; Zhang, Z.; Chen, X.-G.

    2015-02-11

    With its combination of high specific strength, good machinability and excellent weldability, AA2219 direct chill (DC) cast alloy has become a new category of materials for manufacturing large molds for the plastics and automotive industries. The effect of two-step aging on the microstructural evolution and mechanical properties of AA2219 DC cast alloy was investigated. The precipitate microstructure was characterized under different heat treatment conditions using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The poor mechanical properties of the air-quenched alloy were attributed to the presence of quench-induced coarse θ′ and θ precipitates, which had very limited contribution to the precipitation hardening during the aging treatment. The two-step aging treatment of the air-quenched AA2219 alloy involved the precipitation of GP zones in the first step followed by their transformation into fine θ″ strengthening precipitates in the second step, which considerably improved the mechanical properties. After undergoing 120 °C/36 h+190 °C/8 h two-step aging, the hardness, YS and UTS of the air-quenched alloy were increased by 27%, 46% and 15%, respectively, compared with 190 °C/8 h one-step aging.

  5. Pelvic reorientation osteotomies and acetabuloplasties in children. Surgical technique.

    Science.gov (United States)

    Sales de Gauzy, J

    2010-11-01

    The objectives of pelvic osteotomies are to improve femoral head coverage and coxofemoral joint stability. The most currently used osteotomies can be divided into reorientation osteotomies (Salter and Pol le Cœur triple osteotomy) and acetabuloplasties (Pemberton and Dega). All these osteotomies share an identical installation on the table and bikini-type incision. The Salter osteotomy uses a single osteotomy line located at the inferior gluteal line. The Pol Le Cœur triple pelvic osteotomy combines innominate osteotomies of the iliopubic and ischiopubic rami via a genitofemoral approach (inguinal). In these two reorientation osteotomies, the acetabulum tilts in retroversion, improving the anterior and lateral coverage but reducing the posterior coverage. In the Pemberton acetabuloplasty, the osteotomy line is incomplete. It begins anteriorly between the iliac spines and ends posteriorly immediately above the triradiate cartilage. The posterior part of the ilium remains intact. The Pemberton acetabuloplasty causes retroversion and plicature of the acetabulum responsible for reducing its diameter. Anterior and lateral coverage of the femoral head is improved and posterior coverage remains unchanged. In the Dega acetabuloplasty, the osteotomy line is incomplete. It begins laterally above the acetabulum and terminates just above the triradiate cartilage. The medial part of the ilium remains intact. The Dega acetabuloplasty reduces the diameter of the acetabulum and improves overall femoral head coverage (anterior, lateral, and posterior). Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  6. Total knee arthroplasty after high tibial osteotomy. A systematic review

    NARCIS (Netherlands)

    T.M. van Raaij (Tom); M. Reijman (Max); A. Furlan (Alessandro); J.A.N. Verhaar (Jan)

    2009-01-01

    textabstractBackground: Previous osteotomy may compromise subsequent knee replacement, but no guidelines considering knee arthroplasty after prior osteotomy have been developed. We describe a systematic review of non-randomized studies to analyze the effect of high tibial osteotomy on total knee

  7. The Level of Fibula Osteotomy and Incidence of Peroneal Nerve ...

    African Journals Online (AJOL)

    2010-06-29

    Jun 29, 2010 ... Journal of Surgical Technique and Case Report | Jan-Jun 2010 | Vol-2 | Issue-1. 17. The Level of Fibula Osteotomy and Incidence of Peroneal. Nerve Palsy in Proximal Tibial Osteotomy. A. O. Ogbemudia, P. F. A. Umebese, A. Bafor, E. Igbinovia, P. E. Ogbemudia. INTRODUCTION. Osteotomy of the fibula is ...

  8. Intertrochanteric osteotomy for posttraumatic arthritis after acetabular fractures

    NARCIS (Netherlands)

    Marti, R. K.; Chaldecott, L. R.; Kloen, P.

    2001-01-01

    To evaluate the long-term results of intertrochanteric osteotomies for posttraumatic arthritis after acetabular fractures. Retrospective study of eight patients who underwent a total of ten intertrochanteric osteotomies. Two patients underwent two osteotomies of the same hip. Academic Level I trauma

  9. Segmental sandwich osteotomy and tunnel technique for three-dimensional reconstruction of the jaw atrophy: a case report.

    Science.gov (United States)

    Santagata, Mario; Sgaramella, Nicola; Ferrieri, Ivo; Corvo, Giovanni; Tartaro, Gianpaolo; D'Amato, Salvatore

    2017-12-01

    A three-dimensionally favourable mandibular bone crest is desirable to be able to successfully implant placement to meet the aesthetic and functional criteria in the implant-prosthetic rehabilitation. Several surgical procedures have been advocated for bone augmentation of the atrophic mandible, and the sandwich osteotomy is one of these techniques. The aim of the present case report was to assess the suitability of segmental mandibular sandwich osteotomy combined with a tunnel technique of soft tissue. Based on our knowledge, nobody described before the sandwich osteotomy with tunnel technique to improve the healing of the wound and meet the dimensional requirements of preimplant bone augmentation in cases of a severely atrophic mandible. A 59-year-old woman with a severely atrophied right mandible was treated with the sandwich osteotomy technique filled with autologous bone graft harvested by a cortical bone collector from the ramus. Clinical examination revealed that the mandible was edentulous bilaterally from the first molar to the second molar region. Radiographically, atrophy of the mandibular alveolar ridge in the same teeth site was observed. We began to treat the right side. A horizontal osteotomy of the edentulous mandibular bone was then made with a piezoelectric device after tunnel technique of the soft tissue. The segmental mandibular sandwich osteotomy (SMSO) was finished by two (mesial and distal) slightly divergent vertical osteotomies. The entire bone fragment was displaced cranially, and the desirable position was obtained. The gap was filled completely with autologous bone chips harvested from the mandibular ramus through a cortical bone collector. No barrier membranes were used to protect the grafts. The vertical incisions were closing with interruptive suturing of the flaps with a resorbable material. In this way, the suture will not fall on the osteotomy line of the jaw; the result will be a better predictability of soft and hard tissue

  10. Tibial rotational osteotomy for idiopathic torsion. A comparison of the proximal and distal osteotomy levels.

    Science.gov (United States)

    Krengel, W F; Staheli, L T

    1992-10-01

    A retrospective analysis was done of 52 rotational tibial osteotomies (RTOs) performed on 35 patients with severe idiopathic tibial torsion. Thirty-nine osteotomies were performed at the proximal or midtibial level. Thirteen were performed at the distal tibial level with a technique previously described by one of the authors. Serious complications occurred in five (13%) of the proximal and in none of the distal RTOs. For severe and persisting idiopathic tibial torsion, the authors recommend correction by RTO at the distal level. Proximal level osteotomy is indicated only when a varus or valgus deformity required concurrent correction.

  11. Ankle joint pressure changes in a pes cavovarus model: supramalleolar valgus osteotomy versus lateralizing calcaneal osteotomy.

    Science.gov (United States)

    Schmid, Timo; Zurbriggen, Sebastian; Zderic, Ivan; Gueorguiev, Boyko; Weber, Martin; Krause, Fabian G

    2013-09-01

    A fixed cavovarus foot deformity can be associated with anteromedial ankle arthrosis due to elevated medial joint contact stresses. Supramalleolar valgus osteotomies (SMOT) and lateralizing calcaneal osteotomies (LCOT) are commonly used to treat symptoms by redistributing joint contact forces. In a cavovarus model, the effects of SMOT and LCOT on the lateralization of the center of force (COF) and reduction of the peak pressure in the ankle joint were compared. A previously published cavovarus model with fixed hindfoot varus was simulated in 10 cadaver specimens. Closing wedge supramalleolar valgus osteotomies 3 cm above the ankle joint level (6 and 11 degrees) and lateral sliding calcaneal osteotomies (5 and 10 mm displacement) were analyzed at 300 N axial static load (half body weight). The COF migration and peak pressure decrease in the ankle were recorded using high-resolution TekScan pressure sensors. A significant lateral COF shift was observed for each osteotomy: 2.1 mm for the 6 degrees (P = .014) and 2.3 mm for the 11 degrees SMOT (P = .010). The 5 mm LCOT led to a lateral shift of 2.0 mm (P = .042) and the 10 mm LCOT to a shift of 3.0 mm (P = .006). Comparing the different osteotomies among themselves no significant differences were recorded. No significant anteroposterior COF shift was seen. A significant peak pressure reduction was recorded for each osteotomy: The SMOT led to a reduction of 29% (P = .033) for the 6 degrees and 47% (P = .003) for the 11 degrees osteotomy, and the LCOT to a reduction of 41% (P = .003) for the 5 mm and 49% (P = .002) for the 10 mm osteotomy. Similar to the COF lateralization no significant differences between the osteotomies were seen. LCOT and SMOT significantly reduced anteromedial ankle joint contact stresses in this cavovarus model. The unloading effects of both osteotomies were equivalent. More correction did not lead to significantly more lateralization of the COF or more reduction of peak pressure but a trend was

  12. Bilateral agreements

    International Nuclear Information System (INIS)

    1998-01-01

    Ten bilateral agreements are presented. These are: 1) Co-operation agreement relating to the peaceful uses of nuclear energy between Argentina and EURATOM (1996); 2) Agreement on co-operation in the peaceful uses of nuclear energy between Argentina and Greece (1997); 3) Implementing arrangement for technical exchange and co-operation in the area of peaceful uses of nuclear energy between Argentina and the United States (1997); 4) Agreement concerning co-operation in nuclear science and technology between Australia and Indonesia (1997); 5) Implementation of the 1985 Agreement for co-operation concerning the peaceful uses of nuclear energy between the People's Republic of China and the United States (1998); 6) Protocol of co-operation between France and Lithuania (1997); 7) Agreement on co-operation in energy research, science and technology, and development between Germany and the United States (1998); 8) Agreement on early notification of a nuclear accident and exchange of information on nuclear facilities between Greece and Romania (1997); 9) Agreement on early notification of nuclear accidents and co-operation in the field of nuclear safety between Hungary and the Ukraine (1997); 10) Agreement in the field of radioactive waste management between Switzerland and the United States (1997). (K.A.)

  13. [Stress distribution of surgically assisted tooth-borne rapid maxillary expansion via three different types of osteotomies].

    Science.gov (United States)

    Jiang, Wen-hui; Wang, Xu-dong; Wang, Dong-mei

    2009-12-01

    To investigate the stress distribution of craniofacial bones during surgically assisted tooth-borne rapid maxillary expansion (SARME) via three different osteotomies. Three-dimensional finite element model of craniofacial bones with a tooth-borne appliance was generated. According to the different osteotomies, the models were categorized as three groups: Type I-isolated midpalatal osteotomy, Type II-Le Fort I and midpalatal osteotomies, Type III-Le Fort I and midpalatal osteotomies and bilateral pterygomaxillary disjunction. In all three models, with 4 different displacements, von-Mises stress was measured and analysed at 11 anatomical structures of the craniofacial bones. An obvious reduction of the stress was observed followed by the larger extent of the surgery. The maximum stress of the bones was only noticed in Type I model. Stress on lamina of the pterygoid acutely increased in the Type II model compared with the Type I model. In Type III model, after separation of the pterygomaxillary junctions, stress on lamina of the pterygoid decreased rapidly and meanwhile stressed on the majority of the midfacial bones also decreased. In Type III osteotomies, anatomical structures of the upper craniofacial bones suffered from an increase of the stress. Surgical procedures would be of great help to reduce the stress on the craniofacial region in the rapid maxillary expansion postoperatively. Fractures of the cranial base may occur at a greater chance because of stress focusing on lamina of the pterygoid. So, separation of the pterygomaxillary junctions during the operation is suggested. Increasing stress on the upper craniofacial bones can be observed after separation of the pterygomaxillary junctions due to changes of stress transduction pathways.

  14. Subtrochanteric femoral shortening osteotomy combined with cementless total hip replacement for Crowe type IV developmental dysplasia: a retrospective study.

    Science.gov (United States)

    Rollo, Giuseppe; Solarino, Giuseppe; Vicenti, Giovanni; Picca, Girolamo; Carrozzo, Massimiliano; Moretti, Biagio

    2017-12-01

    Total hip replacement for high dislocation of the hip presents some difficulties, considering patients' young ages, the abnormal hip anatomy and the high rate of complications. In this study, we present our experience in terms of clinical and radiological results in the treatment of Crowe type IV hips with subtrochanteric femoral shortening osteotomy and cementless total hip replacement. We retrospectively reviewed 15 patients with Crowe type IV hip dysplasia (two bilateral cases for a total of 17 hips) treated with cementless total hip replacement associated with shortening subtrochanteric osteotomies (nine transversal and eight Z-shape osteotomies) between March 2000 to February 2006. The mean follow-up was 88 months (range 63-133). Harris hip score, leg length discrepancy, neurological status, union status of the osteotomy and the component stability were the criteria of the evaluation. All complications were noted. The mean HHS improved from 38.3 (range 32-52) to 85.6 (range 69-90). The mean preoperative leg length discrepancy was of 45 mm (range 38-70) and reduced to a mean of 12 mm (range 9-1.6) postoperatively. All osteotomies resulted healed at an average of 12.3 weeks (range 10-15). No cases of delayed union or nonunion were detected. Two patients (11%) showed early symptoms of sciatic nerve palsy which resolved uneventfully in 6 months. There was no migrations and none of the implants required revision. Cementless THA with shortening subtrochanteric osteotomy is an effective method in the treatment of patients with Crowe type IV development dysplasia of the hip. IV.

  15. Two-Step Growth of Two-Dimensional WSe2/MoSe2 Heterostructures.

    Science.gov (United States)

    Gong, Yongji; Lei, Sidong; Ye, Gonglan; Li, Bo; He, Yongmin; Keyshar, Kunttal; Zhang, Xiang; Wang, Qizhong; Lou, Jun; Liu, Zheng; Vajtai, Robert; Zhou, Wu; Ajayan, Pulickel M

    2015-09-09

    Two dimensional (2D) materials have attracted great attention due to their unique properties and atomic thickness. Although various 2D materials have been successfully synthesized with different optical and electrical properties, a strategy for fabricating 2D heterostructures must be developed in order to construct more complicated devices for practical applications. Here we demonstrate for the first time a two-step chemical vapor deposition (CVD) method for growing transition-metal dichalcogenide (TMD) heterostructures, where MoSe2 was synthesized first and followed by an epitaxial growth of WSe2 on the edge and on the top surface of MoSe2. Compared to previously reported one-step growth methods, this two-step growth has the capability of spatial and size control of each 2D component, leading to much larger (up to 169 μm) heterostructure size, and cross-contamination can be effectively minimized. Furthermore, this two-step growth produces well-defined 2H and 3R stacking in the WSe2/MoSe2 bilayer regions and much sharper in-plane interfaces than the previously reported MoSe2/WSe2 heterojunctions obtained from one-step growth methods. The resultant heterostructures with WSe2/MoSe2 bilayer and the exposed MoSe2 monolayer display rectification characteristics of a p-n junction, as revealed by optoelectronic tests, and an internal quantum efficiency of 91% when functioning as a photodetector. A photovoltaic effect without any external gates was observed, showing incident photon to converted electron (IPCE) efficiencies of approximately 0.12%, providing application potential in electronics and energy harvesting.

  16. Two-Step Oxidation of Refractory Gold Concentrates with Different Microbial Communities.

    Science.gov (United States)

    Wang, Guo-Hua; Xie, Jian-Ping; Li, Shou-Peng; Guo, Yu-Jie; Pan, Ying; Wu, Haiyan; Liu, Xin-Xing

    2016-11-28

    Bio-oxidation is an effective technology for treatment of refractory gold concentrates. However, the unsatisfactory oxidation rate and long residence time, which cause a lower cyanide leaching rate and gold recovery, are key factors that restrict the application of traditional bio-oxidation technology. In this study, the oxidation rate of refractory gold concentrates and the adaption of microorganisms were analyzed to evaluate a newly developed two-step pretreatment process, which includes a high temperature chemical oxidation step and a subsequent bio-oxidation step. The oxidation rate and recovery rate of gold were improved significantly after the two-step process. The results showed that the highest oxidation rate of sulfide sulfur could reach to 99.01 % with an extreme thermophile microbial community when the pulp density was 5%. Accordingly, the recovery rate of gold was elevated to 92.51%. Meanwhile, the results revealed that moderate thermophiles performed better than acidophilic mesophiles and extreme thermophiles, whose oxidation rates declined drastically when the pulp density was increased to 10% and 15%. The oxidation rates of sulfide sulfur with moderate thermophiles were 93.94% and 65.73% when the pulp density was increased to 10% and 15%, respectively. All these results indicated that the two-step pretreatment increased the oxidation rate of refractory gold concentrates and is a potential technology to pretreat the refractory sample. Meanwhile, owing to the sensitivity of the microbial community under different pulp density levels, the optimization of microbial community in bio-oxidation is necessary in industry.

  17. Apatite grown in niobium by two-step plasma electrolytic oxidation.

    Science.gov (United States)

    Pereira, Bruno Leandro; Lepienski, Carlos Maurício; Mazzaro, Irineu; Kuromoto, Neide Kazue

    2017-08-01

    Plasma electrolytic oxidation (PEO) of niobium plates were done electrochemically in two steps with electrolytes containing phosphorous and calcium being observed the formation of crystalline apatite. All samples were submitted to a first step of PEO using an electrolyte containing phosphate ions. The second oxidization step was made using three different electrolytes. Some samples were oxidized by PEO in electrolyte containing calcium, while in other samples it was used two mixtures of phosphoric acid and calcium acetate monohydrate solutions. Three different surface layers were obtained. The morphology and chemical composition of the films were analyzed by scanning electronic microscopy (SEM), and energy dispersive spectroscopy (EDS) respectively. It was observed that all samples submitted to two-step oxidation shown porous surface and a calcium and phosphorus rich layer. Average surface roughness (Ra) was measured by a profilometer remaining in the sub-micrometric range. The contact angle by sessile drop technique, using 1μL of distilled water was performed with an optical goniometer. It was verified a higher hydrophilicity in all surfaces compared to the polished niobium. Orthorhombic Nb 2 O 5 was identified by XRD in the oxide layer. Crystalline apatite was identified by XRD in surfaces after the second oxidation made with the Ca-rich electrolyte and a mixture of an electrolyte richer in Ca compared to P. These results indicate that a two-step oxidized niobium surface present great features for applications in the osseointegration processes: favorable chemical composition that increase the biocompatibility, the formation of crystalline niobium pentoxide (orthorhombic), high hydrophilicity and formation of crystalline calcium phosphate (apatite) under adequate electrolyte composition. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Effects of Two-Step Transamidation of Wheat Semolina on the Technological Properties of Gluten

    Directory of Open Access Journals (Sweden)

    Salvatore Moscaritolo

    2016-06-01

    Full Text Available Celiac disease (CD is an immune-mediated disorder caused by the ingestion of wheat gluten. A lifelong, gluten-free diet is required to alleviate symptoms and to normalize the intestinal mucosa. We previously found that transamidation reaction by microbial transglutaminase (mTG was effective in down-regulating the gliadin-specific immune response in CD patients. In this study, the two-step transamidation protocol was adopted to treat commercial wheat semolina on a pilot scale. The effectiveness of the enzymatic reaction was tested by means of consolidated biochemical and immunological methods on isolated prolamins. We found that water-insoluble gliadin and glutenin yields decreased in wheat semolina to 5.9% ± 0.3% and 11.6% ± 0.1%, respectively, after a two-step transamidation reaction. Using DQ8 transgenic mice as a model of gluten sensitivity, we observed a dramatic reduction in IFN-γ production in spleen cells challenged in vitro with the residual insoluble gliadin from transamidated semolina (N = 6; median values: 850 vs. 102; control vs. transamidated semolina, p < 0.05. The technological properties of treated wheat semolina were then tested by manufacturing classical pasta (spaghetti. Notably, the spaghetti manufactured with transamidated semolina had only minor changes in its features before and after cooking. In conclusion, the two-step transamidation reaction modified the immunogenic epitopes of gliadins also on a pilot-scale level without influencing the main technological properties of semolina. Our data shed further light on a detoxification strategy alternative to the current gluten-free diet and may have important implications for the management of CD patients.

  19. Influence of ageing on self-etch adhesives: one-step vs. two-step systems.

    Science.gov (United States)

    Marchesi, Giulio; Frassetto, Andrea; Visintini, Erika; Diolosà, Marina; Turco, Gianluca; Salgarello, Stefano; Di Lenarda, Roberto; Cadenaro, Milena; Breschi, Lorenzo

    2013-02-01

    The aim of this study was to evaluate microtensile bond strength (μTBS) to dentine, interfacial nanoleakage expression, and stability after ageing, of two-step vs. one-step self-etch adhesives. Human molars were cut to expose middle/deep dentine, assigned to groups (n = 15), and treated with the following bonding systems: (i) Optibond XTR (a two-step self-etch adhesive; Kerr), (ii) Clearfil SE Bond (a two-step self-etch adhesive; Kuraray), (iii) Adper Easy Bond (a one-step self-etch adhesive; 3M ESPE), and (iv) Bond Force (a one-step self-etch adhesive; Tokuyama). Specimens were processed for μTBS testing after 24 h, 6 months, or 1 yr of storage in artificial saliva at 37°C. Nanoleakage expression was examined in similarly processed additional specimens. At baseline the μTBS results ranked in the following order: Adper Easy Bond = Optibond XTR ≥Clearfil SE = Bond Force, and interfacial nanoleakage analysis showed Clearfil SE Bond = Adper Easy Bond = Optibond XTR> Bond Force. After 1 yr of storage, Optibond XTR, Clearfil SE Bond, and Adper Easy Bond showed higher μTBS and lower interfacial nanoleakage expression compared with Bond Force. In conclusion, immediate bond strength, nanoleakage expression, and stability over time were not related to the number of steps of the bonding systems, but to their chemical formulations. © 2012 Eur J Oral Sci.

  20. Development of F2 two-step fluorination process for non-aqueous reprocessing

    International Nuclear Information System (INIS)

    1976-02-01

    To establish the F 2 two-step fluorination for stable and high recoveries of plutonium, the fluorination process has been studied with the simulated fuel to a FBR containing UO 2 - PuO 2 and non-radioactive fission products in the 2''phi fluid-bed. The process principle was demonstrated and the effect of FPs on fluorination of U and Pu and the possibility of reducing the Pu loss could be clarified. The feasibility of separating PuF 6 from UF 6 onto UO 2 F 2 by adsorption, was also indicated. (auth.)

  1. Simultaneous separation and determination of hydrocarbons and organochlorine compounds by using a two-step microcolumn.

    Science.gov (United States)

    Rodriguez, O M; Desideri, P G; Lepri, L; Checchini, L

    1991-08-30

    The simultaneous separation and determination of a mixture of hydrocarbons and organochlorine compounds was successfully carried out by using sorption chromatography on a two-step microcolumn of silica and aluminium oxide for their fractionation, and a dual detector system. In addition to the separation and identification of hydrocarbons and heterocompounds containing nitrogen, oxygen and sulphur atoms, separation and identification of chlorinated hydrocarbons (dichlorobenzenes, p-chlorotoluene, hexachlorobutadiene, 1,2,4-trichlorobenzene and 2-chloronaphthalene), pesticides (chlorpicrin, aldrin, lindane, alpha- and beta-benzene hexachloride (BHC), endrin, dieldrin, endosulphan, methoxychlor) and herbicides (propanil, dichlobenil, trifluralin, difolatan) were achieved in mixtures containing polychlorinated biphenyl, strobane and chlordane.

  2. Safety of the two-step tuberculin skin test in Indian health care workers.

    Science.gov (United States)

    Christopher, Devasahayam J; Shankar, Deepa; Datey, Ashima; Zwerling, Alice; Pai, Madhukar

    2014-12-01

    Health care workers (HCW) in low and middle income countries are at high risk of nosocomial tuberculosis infection. Periodic screening of health workers for both TB disease and infection can play a critical role in TB infection control. Occupational health programs that implement serial tuberculin skin testing (TST) are advised to use a two-step baseline TST. This helps to ensure that boosting of waned immune response is not mistaken as new TB infection (i.e. conversion). However, there are no data on safety of the two-step TST in the Indian context where HCWs are repeatedly exposed. Nursing students were recruited from 2007 to 2009 at the Christian Medical College and Hospital, Vellore, India. Consenting nursing students were screened with a baseline two-step TST at the time of recruitment. From 2007 to 2008 adverse events were recorded when reported during the TST reading (Cohort A). Nurses recruited in the final study year (2009) answered an investigator administered questionnaire assessing all likely side-effects Cohort B). This information was extracted from the case report forms and analysed. Between 2007 and 09, 800 trainees consented to participate in the annual TB screening study and 779 did not have a past history of TB or recall a positive TST and were selected to administer TST. Of these, 755 returned for reading the result and had complete data and were included for the final analysis - 623 subjects in (cohort A) and 132 in (cohort B). These were included for the final analysis. In cohort A only 1.3% reported adverse events. In cohort B, as per the investigator administered questionnaire; 25% reported minor side effects. Itching and local pain were the most common side effects encountered. There were no major adverse events reported. In particular, the adverse events were similar in the second step of the test and not more severe. Screening of HCWs with two-step TST for LTBI is simple and safe, and hence suitable for wide scale implementation in high

  3. Maximizing Efficiency in Two-step Solar-thermochemical Fuel Production

    Energy Technology Data Exchange (ETDEWEB)

    Ermanoski, I. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-05-01

    Widespread solar fuel production depends on its economic viability, largely driven by the solar-to-fuel conversion efficiency. In this paper, the material and energy requirements in two-step solar-thermochemical cycles are considered.The need for advanced redox active materials is demonstrated, by considering the oxide mass flow requirements at a large scale. Two approaches are also identified for maximizing the efficiency: optimizing reaction temperatures, and minimizing the pressure in the thermal reduction step by staged thermal reduction. The results show that each approach individually, and especially the two in conjunction, result in significant efficiency gains.

  4. Two-Step Proximal Gradient Algorithm for Low-Rank Matrix Completion

    Directory of Open Access Journals (Sweden)

    Qiuyu Wang

    2016-06-01

    Full Text Available In this paper, we  propose a two-step proximal gradient algorithm to solve nuclear norm regularized least squares for the purpose of recovering low-rank data matrix from sampling of its entries. Each iteration generated by the proposed algorithm is a combination of the latest three points, namely, the previous point, the current iterate, and its proximal gradient point. This algorithm preserves the computational simplicity of classical proximal gradient algorithm where a singular value decomposition in proximal operator is involved. Global convergence is followed directly in the literature. Numerical results are reported to show the efficiency of the algorithm.

  5. Normal Range of Head-to-body Delivery Interval by Two-step Delivery

    Directory of Open Access Journals (Sweden)

    Hong-Yu Zhang

    2016-01-01

    Conclusions: The average time of head-to-body delivery interval was longer than 60 s by two-step delivery. Majority shoulders were delivered at the first contraction. Majority shoulders emerged from perineum rather from under pubic arch. The routine one-step method of shoulder delivery where the downward force applied is not necessary and is not the right direction. Baby's breath, making faces, sucking, bubble from noses and mouth, and the light blue color of the faces, all those signs during shoulder delivery indicated a normal live birth.

  6. A Predictable Approach for Osteotomy in Rhinoplasty: A New Concept of Open External Osteotomy

    Science.gov (United States)

    Hontanilla, Bernardo; Cabello, Alvaro

    2016-01-01

    Summary: Nasal osteotomies are a cornerstone step for closing an open roof deformity after dorsal hump surgery. Notwithstanding, the optimal method of nasal osteotomy remains controversial, as evidenced by the variety of approaches with no consensus between authors. Moreover, the election of the technique responds to surgeon’s preference. We proposed a new way to perform both medial and lateral osteotomies under direct vision. Direct vision of nasal osteotomies provides more predictable control and precision than blind procedures, making this procedure more reliable and easier for both novel and experienced surgeons. Other advantages include conservation of nasal muscle, angular vasculature, and periosteum, which allow less postoperative ecchymosis and edema and less risk of synechia and lacrimal sac injury. PMID:27482503

  7. KCNE1 divides the voltage sensor movement in KCNQ1/KCNE1 channels into two steps

    Science.gov (United States)

    Barro-Soria, Rene; Rebolledo, Santiago; Liin, Sara I.; Perez, Marta E.; Sampson, Kevin J.; Kass, Robert S.; Larsson, H. Peter

    2014-04-01

    The functional properties of KCNQ1 channels are highly dependent on associated KCNE-β subunits. Mutations in KCNQ1 or KCNE subunits can cause congenital channelopathies, such as deafness, cardiac arrhythmias and epilepsy. The mechanism by which KCNE1-β subunits slow the kinetics of KCNQ1 channels is a matter of current controversy. Here we show that KCNQ1/KCNE1 channel activation occurs in two steps: first, mutually independent voltage sensor movements in the four KCNQ1 subunits generate the main gating charge movement and underlie the initial delay in the activation time course of KCNQ1/KCNE1 currents. Second, a slower and concerted conformational change of all four voltage sensors and the gate, which opens the KCNQ1/KCNE1 channel. Our data show that KCNE1 divides the voltage sensor movement into two steps with widely different voltage dependences and kinetics. The two voltage sensor steps in KCNQ1/KCNE1 channels can be pharmacologically isolated and further separated by a disease-causing mutation.

  8. Synthesis of β-Nicotinamide Riboside Using an Efficient Two-Step Methodology.

    Science.gov (United States)

    Zhang, Ning; Sauve, Anthony A

    2017-12-24

    A two-step chemical method for the synthesis of β-nicotinamide riboside (NR) is described. NR has achieved wide use as an NAD + precursor (vitamin B3) and can significantly increase central metabolite NAD + concentrations in mammalian cells. β-NR can be prepared with an efficient two-step procedure. The synthesis is initiated via coupling of commercially available 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose with ethyl nicotinate in the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf). 1 H NMR showed that the product was formed with complete stereoselectivity to produce only the β-isomer in high yield (>90% versus starting sugar). The clean stereochemical result suggests that the coupling proceeds via a cationic cis-1,2-acyloxonium-sugar intermediate, which controls addition by nucleophiles to generate predominantly β-stereochemistry. The subsequent deprotection of esters in methanolic ammonia generates the desired product in 85% overall yield versus sugar. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  9. Production of Biodiesel from Acid Oil via a Two-Step Enzymatic Transesterification.

    Science.gov (United States)

    Choi, Nakyung; Lee, Jeom-Sig; Kwak, Jieun; Lee, Junsoo; Kim, In-Hwan

    2016-11-01

    A two-step enzymatic transesterification process in a solvent-free system has been developed as a novel approach to the production of biodiesel using acid oil from rice bran oil soapstock. The acid oil consisted of 53.7 wt% fatty acids, 2.4 wt% monoacylglycerols, 9.1 wt% diacylglycerols, 28.8 wt% triacylglycerols, and 6.0 wt% others. Three immobilized lipases were evaluated as potential biocatalysts, including Novozym 435 from Candida antarctica, Lipozyme RM IM from Rhizomucor miehei, and Lipozyme TL IM from Thermomyces lanuginosus. The effects of molar ratio of acid oil to ethanol, temperature, and enzyme loading were investigated to determine the optimum conditions for the transesterification with the three immobilized lipases. The optimum conditions of the three immobilized lipases were a molar ratio of 1:5 (acid oil to ethanol), the temperature range of 30-40°C, and the enzyme loading range of 5-10%. The two-step transesterification was then conducted under the optimum conditions of each lipase. The stepwise use of Novozym 435 and Lipozyme TL IM or Lipozyme RM IM and Lipozyme TL IM resulted in similar or higher levels of yield to the individual lipases. The maximum yields obtained in both stepwise uses were ca. 92%.

  10. A Two-Step Approach to Uncertainty Quantification of Core Simulators

    Directory of Open Access Journals (Sweden)

    Artem Yankov

    2012-01-01

    Full Text Available For the multiple sources of error introduced into the standard computational regime for simulating reactor cores, rigorous uncertainty analysis methods are available primarily to quantify the effects of cross section uncertainties. Two methods for propagating cross section uncertainties through core simulators are the XSUSA statistical approach and the “two-step” method. The XSUSA approach, which is based on the SUSA code package, is fundamentally a stochastic sampling method. Alternatively, the two-step method utilizes generalized perturbation theory in the first step and stochastic sampling in the second step. The consistency of these two methods in quantifying uncertainties in the multiplication factor and in the core power distribution was examined in the framework of phase I-3 of the OECD Uncertainty Analysis in Modeling benchmark. With the Three Mile Island Unit 1 core as a base model for analysis, the XSUSA and two-step methods were applied with certain limitations, and the results were compared to those produced by other stochastic sampling-based codes. Based on the uncertainty analysis results, conclusions were drawn as to the method that is currently more viable for computing uncertainties in burnup and transient calculations.

  11. Signatures of two-step impurity mediated vortex lattice melting in Bose-Einstein condensate

    Science.gov (United States)

    Dey, Bishwajyoti

    2017-04-01

    We study impurity mediated vortex lattice melting in a rotating two-dimensional Bose-Einstein condensate (BEC). Impurities are introduced either through a protocol in which vortex lattice is produced in an impurity potential or first creating the vortex lattice in the absence of random pinning and then cranking up the impurity potential. These two protocols have obvious relation with the two commonly known protocols of creating vortex lattice in a type-II superconductor: zero field cooling protocol and the field cooling protocol respectively. Time-splitting Crank-Nicolson method has been used to numerically simulate the vortex lattice dynamics. It is shown that the vortex lattice follows a two-step melting via loss of positional and orientational order. This vortex lattice melting process in BEC closely mimics the recently observed two-step melting of vortex matter in weakly pinned type-II superconductor Co-intercalated NbSe2. Also, using numerical perturbation analysis, we compare between the states obtained in two protocols and show that the vortex lattice states are metastable and more disordered when impurities are introduced after the formation of an ordered vortex lattice. The author would like to thank SERB, Govt. of India and BCUD-SPPU for financial support through research Grants.

  12. Assessment of assembly homogenized two-steps core dynamic calculations using direct whole core transport solutions

    International Nuclear Information System (INIS)

    Hursin, Mathieu; Downar, Thomas J.; Yoon, Joo Il; Joo, Han Gyu

    2016-01-01

    Highlights: • Reactivity initiated accident analysis with direct whole core transient transport code. • Comparison with usual “two steps” procedure. • Effect of effective delayed neutron fraction definition on energy deposition in the fuel. • Effect of homogenized few-group cross sections generation at the assembly level on energy deposition in the fuel. • Effect of effective fuel temperature definition on energy deposition in the fuel. - Abstract: The impact of the approximations in the “two-steps” procedure used in the current generation of nodal simulators for core transient calculations is assessed by using a higher order solution obtained from a direct, whole core, transient transport calculation. A control rod ejection accident in an idealized minicore is analyzed with PARCS, which uses the two-steps procedure and DeCART which provides the higher order solution. DeCART is used as lattice code to provide the homogenized cross sections and kinetics parameters to PARCS. The approximations made by using (1) the homogenized few-group cross sections and kinetic parameters generated at the assembly level, (2) an effective delayed neutrons fraction, (3) an effective fuel temperature and (4) the few-group formulation are investigated in terms of global and local core power behavior. The results presented in the paper show that the current two-steps procedure produces sufficiently accurate transient results with respect to the direct whole core calculation solution, provided that its parameters are carefully generated using the prescriptions described in the present article.

  13. A two-step iterative method for evolving nonlinear acoustic systems to a steady-state

    Science.gov (United States)

    Watson, Willie R.; Myers, Michael K.

    1990-01-01

    A new approach for evolving two-dimensional nonlinear acoustic systems with flow to a steady state is presented. The approach is a two-step iterative method which is tested on a benchmark acoustic problem for which an exact analytical solution is available. Results are also calculated for a nonlinear acoustic problem for which an exact analytical solution is not known. Results indicate that the two-step method represents a powerful, efficient, and stable method for evolving two-dimensional acoustic systems to a steady state, and that the method is applicable to any number of spatial dimensions and to other hyperbolic systems. It is noted that for the benchmark problem only a single iteration on the method is required when the transient and steady-state field are of the same order of magnitude; however, four iterations are required when the steady-state field is several orders of magnitude smaller than the transient field. This method requires six iterations before achieving a steady state for the nonlinear test problem.

  14. Two-step excitation and blue fluorescence under continuous-wave pumping in Nd:YLF

    Science.gov (United States)

    Fan, T. Y.; Byer, Robert L.

    1986-01-01

    Near-UV and blue fluorescence from the 4D3/2 and 4D5/2 manifolds in Nd:YLF has been observed at room temperature under CW pumping by a rhodamine 590 dye laser. Excitation to these manifolds is attributed to two-step excitation involving excited-state absorption from the 4F3/2 metastable level. A similar phenomenon has also been observed in Nd:YAG and Nd:glass. The effective excited-state absorption cross section is measured to be (2 + or - 1) x 10 to the -20th sq cm at 587.4 nm in the pi polarization, and the peak effective stimulated emission cross section is measured to be 5 x 10 to the -20th sq cm at 411.7 nm, also in the pi polarization. Estimated laser threshold at 411.7 nm for two-step pumping at 587.4 nm is 70 mW.

  15. Two-step bioleaching of copper and gold from discarded printed circuit boards (PCB).

    Science.gov (United States)

    Işıldar, Arda; van de Vossenberg, Jack; Rene, Eldon R; van Hullebusch, Eric D; Lens, Piet N L

    2016-11-01

    An effective strategy for environmentally sound biological recovery of copper and gold from discarded printed circuit boards (PCB) in a two-step bioleaching process was experimented. In the first step, chemolithotrophic acidophilic Acidithiobacillus ferrivorans and Acidithiobacillus thiooxidans were used. In the second step, cyanide-producing heterotrophic Pseudomonas fluorescens and Pseudomonas putida were used. Results showed that at a 1% pulp density (10g/L PCB concentration), 98.4% of the copper was bioleached by a mixture of A. ferrivorans and A. thiooxidans at pH 1.0-1.6 and ambient temperature (23±2°C) in 7days. A pure culture of P. putida (strain WCS361) produced 21.5 (±1.5)mg/L cyanide with 10g/L glycine as the substrate. This gold complexing agent was used in the subsequent bioleaching step using the Cu-leached (by A. ferrivorans and A. thiooxidans) PCB material, 44.0% of the gold was mobilized in alkaline conditions at pH 7.3-8.6, and 30°C in 2days. This study provided a proof-of-concept of a two-step approach in metal bioleaching from PCB, by bacterially produced lixiviants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. A two-step procedure for automatic and accurate segmentation of volumetric CLSM biofilm images.

    Science.gov (United States)

    Yerly, Jerome; Hu, Yaoping; Jones, Steven M; Martinuzzi, Robert J

    2007-09-01

    This paper presents a robust two-step segmentation procedure for the study of biofilm structure. Without user intervention, the procedure segments volumetric biofilm images generated by a confocal laser scanning microscopy (CLSM). This automated procedure implements an anisotropic diffusion filter as a preprocessing step and a 3D extension of the Otsu method for thresholding. Applying the anisotropic diffusion filter to even low-contrast CLSM images significantly improves the segmentation obtained with the 3D Otsu method. A comparison of the results for several CLSM data sets demonstrated that the accuracy of this procedure, unlike that of the objective threshold selection algorithm (OTS), is not affected by biofilm coverage levels and thus fills an important gap in developing a robust and objective segmenting procedure. The effectiveness of the present segmentation procedure is shown for CLSM images containing different bacterial strains. The image saturation handling capability of this procedure relaxes the constraints on user-selected gain and intensity settings of a CLSM. Therefore, this two-step procedure provides an automatic and accurate segmentation of biofilms that is independent of biofilm coverage levels and, in turn, lays a solid foundation for achieving objective analysis of biofilm structural parameters.

  17. Fabrication of conductive copper patterns using reactive inkjet printing followed by two-step electroless plating

    International Nuclear Information System (INIS)

    Chen, Jin-Ju; Lin, Guo-Qiang; Wang, Yan; Sowade, Enrico; Baumann, Reinhard R.; Feng, Zhe-Sheng

    2017-01-01

    Highlights: • Copper patterns were fabricated by reactive inkjet printing and two-step electroless plating. • Cu particles produced via reactive inkjet printing act as catalyst for copper electroless plating. • High conductivity can be obtained without many printing passes and high temperature sintering. • This approach can largely avoid nozzle-clogging problems. • This approach presents a potential way in the flexible printed electronics with simple process. - Abstract: A simple and low-cost process for fabricating conductive copper patterns on flexible polyimide substrates was demonstrated. Copper catalyst patterns were first produced on polyimide substrates using reactive inkjet printing of Cu (II)-bearing ink and reducing ink, and then the conductive copper patterns were generated after a two-step electroless plating procedure. The copper layers were characterized by optical microscope, SEM, XRD and EDS. Homogeneously distributed copper nanoclusters were found in the catalyst patterns. A thin copper layer with uniform particle size was formed after first-step electroless plating, and a thick copper layer of about 14.3 μm with closely packed structure and fine crystallinity was produced after second-step electroless plating. This resulting copper layer had good solderability, reliable adhesion strength and a low resistivity of 5.68 μΩ cm without any sintering process.

  18. Two-level image authentication by two-step phase-shifting interferometry and compressive sensing

    Science.gov (United States)

    Zhang, Xue; Meng, Xiangfeng; Yin, Yongkai; Yang, Xiulun; Wang, Yurong; Li, Xianye; Peng, Xiang; He, Wenqi; Dong, Guoyan; Chen, Hongyi

    2018-01-01

    A two-level image authentication method is proposed; the method is based on two-step phase-shifting interferometry, double random phase encoding, and compressive sensing (CS) theory, by which the certification image can be encoded into two interferograms. Through discrete wavelet transform (DWT), sparseness processing, Arnold transform, and data compression, two compressed signals can be generated and delivered to two different participants of the authentication system. Only the participant who possesses the first compressed signal attempts to pass the low-level authentication. The application of Orthogonal Match Pursuit CS algorithm reconstruction, inverse Arnold transform, inverse DWT, two-step phase-shifting wavefront reconstruction, and inverse Fresnel transform can result in the output of a remarkable peak in the central location of the nonlinear correlation coefficient distributions of the recovered image and the standard certification image. Then, the other participant, who possesses the second compressed signal, is authorized to carry out the high-level authentication. Therefore, both compressed signals are collected to reconstruct the original meaningful certification image with a high correlation coefficient. Theoretical analysis and numerical simulations verify the feasibility of the proposed method.

  19. Identification of two-step chemical mechanisms using small temperature oscillations and a single tagged species.

    Science.gov (United States)

    Closa, F; Gosse, C; Jullien, L; Lemarchand, A

    2015-05-07

    In order to identify two-step chemical mechanisms, we propose a method based on a small temperature modulation and on the analysis of the concentration oscillations of a single tagged species involved in the first step. The thermokinetic parameters of the first reaction step are first determined. Then, we build test functions that are constant only if the chemical system actually possesses some assumed two-step mechanism. Next, if the test functions plotted using experimental data are actually even, the mechanism is attributed and the obtained constant values provide the rate constants and enthalpy of reaction of the second step. The advantage of the protocol is to use the first step as a probe reaction to reveal the dynamics of the second step, which can hence be relieved of any tagging. The protocol is anticipated to apply to many mechanisms of biological relevance. As far as ligand binding is considered, our approach can address receptor conformational changes or dimerization as well as competition with or modulation by a second partner. The method can also be used to screen libraries of untagged compounds, relying on a tracer whose concentration can be spectroscopically monitored.

  20. a Two-Step Classification Approach to Distinguishing Similar Objects in Mobile LIDAR Point Clouds

    Science.gov (United States)

    He, H.; Khoshelham, K.; Fraser, C.

    2017-09-01

    Nowadays, lidar is widely used in cultural heritage documentation, urban modeling, and driverless car technology for its fast and accurate 3D scanning ability. However, full exploitation of the potential of point cloud data for efficient and automatic object recognition remains elusive. Recently, feature-based methods have become very popular in object recognition on account of their good performance in capturing object details. Compared with global features describing the whole shape of the object, local features recording the fractional details are more discriminative and are applicable for object classes with considerable similarity. In this paper, we propose a two-step classification approach based on point feature histograms and the bag-of-features method for automatic recognition of similar objects in mobile lidar point clouds. Lamp post, street light and traffic sign are grouped as one category in the first-step classification for their inter similarity compared with tree and vehicle. A finer classification of the lamp post, street light and traffic sign based on the result of the first-step classification is implemented in the second step. The proposed two-step classification approach is shown to yield a considerable improvement over the conventional one-step classification approach.

  1. A TWO-STEP CLASSIFICATION APPROACH TO DISTINGUISHING SIMILAR OBJECTS IN MOBILE LIDAR POINT CLOUDS

    Directory of Open Access Journals (Sweden)

    H. He

    2017-09-01

    Full Text Available Nowadays, lidar is widely used in cultural heritage documentation, urban modeling, and driverless car technology for its fast and accurate 3D scanning ability. However, full exploitation of the potential of point cloud data for efficient and automatic object recognition remains elusive. Recently, feature-based methods have become very popular in object recognition on account of their good performance in capturing object details. Compared with global features describing the whole shape of the object, local features recording the fractional details are more discriminative and are applicable for object classes with considerable similarity. In this paper, we propose a two-step classification approach based on point feature histograms and the bag-of-features method for automatic recognition of similar objects in mobile lidar point clouds. Lamp post, street light and traffic sign are grouped as one category in the first-step classification for their inter similarity compared with tree and vehicle. A finer classification of the lamp post, street light and traffic sign based on the result of the first-step classification is implemented in the second step. The proposed two-step classification approach is shown to yield a considerable improvement over the conventional one-step classification approach.

  2. Evolution of Cobalt Oxide Nanostructures on Glass Substrate via Two Step Solution Route Synthesis

    Science.gov (United States)

    Mariscal, A. R.; Marquez, M. C.

    2017-06-01

    Controlling the morphology in the nanoscale has proven to be an effective way to drastically change the properties of materials. In this study, several morphologies of cobalt oxide (Co3O4) were synthesized by employing a two-step solution route. A Co3O4 seed layer was first deposited on the glass substrate via spin Coating using a Cobalt acetate precursor followed by chemical bath deposition of another Co3O4 layer using cobalt nitrate precursor. The effect of the seed layer and the deposition times on the morphology of the secondary Co3O4 nanostructures was verified by employing scanning electron microscopy (SEM). Morphologies like nanoplatelets, nanorods, nanofibrils and porous nanowalls were observed in the SEM. Other characterization techniques such as Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction technique (XRD) were used to elucidate the formation of Co3O4. Furthermore, the surface of the seed layer was determined via atomic force microscope. It was found that the roughness of the seed layer ranges from ~0.3 to 3 nm depending on the concentration of the cobalt precursor used. Results showed that the morphology of Co3O4 can be easily modified using the two-step solution route technique. The alterations of the morphology of Co3O4 could lead to morphologies with unique properties and development of functional materials applicable in the field of energy and electronics.

  3. Design of a Two-Step Calibration Method of Kinematic Parameters for Serial Robots

    Science.gov (United States)

    WANG, Wei; WANG, Lei; YUN, Chao

    2017-03-01

    Serial robots are used to handle workpieces with large dimensions, and calibrating kinematic parameters is one of the most efficient ways to upgrade their accuracy. Many models are set up to investigate how many kinematic parameters can be identified to meet the minimal principle, but the base frame and the kinematic parameter are indistinctly calibrated in a one-step way. A two-step method of calibrating kinematic parameters is proposed to improve the accuracy of the robot's base frame and kinematic parameters. The forward kinematics described with respect to the measuring coordinate frame are established based on the product-of-exponential (POE) formula. In the first step the robot's base coordinate frame is calibrated by the unit quaternion form. The errors of both the robot's reference configuration and the base coordinate frame's pose are equivalently transformed to the zero-position errors of the robot's joints. The simplified model of the robot's positioning error is established in second-power explicit expressions. Then the identification model is finished by the least square method, requiring measuring position coordinates only. The complete subtasks of calibrating the robot's 39 kinematic parameters are finished in the second step. It's proved by a group of calibration experiments that by the proposed two-step calibration method the average absolute accuracy of industrial robots is updated to 0.23 mm. This paper presents that the robot's base frame should be calibrated before its kinematic parameters in order to upgrade its absolute positioning accuracy.

  4. Preparation and photocatalytic degradation performance of Ag3PO4 with a two-step approach

    International Nuclear Information System (INIS)

    Li, Jiwen; Ji, Xiaojing; Li, Xian; Hu, Xianghua; Sun, Yanfang; Ma, Jingjun; Qiao, Gaowei

    2016-01-01

    Highlights: • Ag 3 PO 4 photocatalysts were synthesized via one-step and two-step ion-exchange reaction. • Photocatalytic properties of Ag 3 PO 4 photocatalysts was investigated, the result indicated the Ag 3 PO 4 (2) was higher than that of Ag 3 PO 4 (1) under the same experimental condition. • Ag 3 PO 4 (2) particles were larger than Ag 3 PO 4 (1) particles and many polygonal-shaped surfaces could be clearly observed in the Ag 3 PO 4 (2) particles. - Abstract: Ag 3 PO 4 photocatalysts were prepared via two and one-step through a facile ion-exchange route. The photocatalysts were then characterized through powder X-ray diffraction, scanning electron microscopy and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the samples was evaluated on the basis of the photocatalytic degradation of methyl orange (MO) and methylene blue (MB) under solar irradiation. The MO degradation rate of the Photocatalyst synthesized by the two-step ion-exchange route was 89.18% in 60 min. This value was four times that of the Photocatalyst synthesized by the one-step approach.The MB degradation rate was 97% in 40 min. After six cycling runs were completed, the MO degradation rate was 73%

  5. A two-step method for developing a control rod program for boiling water reactors

    International Nuclear Information System (INIS)

    Taner, M.S.; Levine, S.H.; Hsiao, M.Y.

    1992-01-01

    This paper reports on a two-step method that is established for the generation of a long-term control rod program for boiling water reactors (BWRs). The new method assumes a time-variant target power distribution in core depletion. In the new method, the BWR control rod programming is divided into two steps. In step 1, a sequence of optimal, exposure-dependent Haling power distribution profiles is generated, utilizing the spectral shift concept. In step 2, a set of exposure-dependent control rod patterns is developed by using the Haling profiles generated at step 1 as a target. The new method is implemented in a computer program named OCTOPUS. The optimization procedure of OCTOPUS is based on the method of approximation programming, in which the SIMULATE-E code is used to determine the nucleonics characteristics of the reactor core state. In a test in cycle length over a time-invariant, target Haling power distribution case because of a moderate application of spectral shift. No thermal limits of the core were violated. The gain in cycle length could be increased further by broadening the extent of the spetral shift

  6. Feature theory and the two-step hypothesis of Müllerian mimicry evolution.

    Science.gov (United States)

    Balogh, Alexandra Catherine Victoria; Gamberale-Stille, Gabriella; Tullberg, Birgitta Sillén; Leimar, Olof

    2010-03-01

    The two-step hypothesis of Müllerian mimicry evolution states that mimicry starts with a major mutational leap between adaptive peaks, followed by gradual fine-tuning. The hypothesis was suggested to solve the problem of apostatic selection producing a valley between adaptive peaks, and appears reasonable for a one-dimensional phenotype. Extending the hypothesis to the realistic scenario of multidimensional phenotypes controlled by multiple genetic loci can be problematic, because it is unlikely that major mutational leaps occur simultaneously in several traits. Here we consider the implications of predator psychology on the evolutionary process. According to feature theory, single prey traits may be used by predators as features to classify prey into discrete categories. A mutational leap in such a trait could initiate mimicry evolution. We conducted individual-based evolutionary simulations in which virtual predators both categorize prey according to features and generalize over total appearances. We found that an initial mutational leap toward feature similarity in one dimension facilitates mimicry evolution of multidimensional traits. We suggest that feature-based predator categorization together with predator generalization over total appearances solves the problem of applying the two-step hypothesis to complex phenotypes, and provides a basis for a theory of the evolution of mimicry rings.

  7. A modified Bragg and Williams approximation of the two-step spin crossover

    International Nuclear Information System (INIS)

    Koudriavtsev, A.B.

    1999-01-01

    The expressions for free energy of a binary mixture with chemical equilibrium in a simple cubic lattice have been obtained as functions of energy spacings and degree of ordering supposing that the partition function of a molecule in a lattice centre is dependent on the nature of two nearest neighbours along each normal coordinate. The derived equations contain linear, square and cubic (besides logarithmic) terms with respect to mole fraction of reactants as well as quadratic terms with respect to the degree of ordering. Under simplifying conditions these equations are transformed into the equations of regular solutions theory. The Bragg-Williams approximation of binary ordered system employing regular solution theory expressions for free energy qualitatively predicts a two-step spin crossover. The use of modified expressions for free energy in a Bragg and Williams approximation results in a quantitative description of literature data on the two-step spin-crossover in [Fe(2-pic) 3 ]Cl 2 EtOH. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  8. Novel two-step method to form silk fibroin fibrous hydrogel

    International Nuclear Information System (INIS)

    Ming, Jinfa; Li, Mengmeng; Han, Yuhui; Chen, Ying; Li, Han; Zuo, Baoqi; Pan, Fukui

    2016-01-01

    Hydrogels prepared by silk fibroin solution have been studied. However, mimicking the nanofibrous structures of extracellular matrix for fabricating biomaterials remains a challenge. Here, a novel two-step method was applied to prepare fibrous hydrogels using regenerated silk fibroin solution containing nanofibrils in a range of tens to hundreds of nanometers. When the gelation process of silk solution occurred, it showed a top-down type gel within 30 min. After gelation, silk fibroin fibrous hydrogels exhibited nanofiber network morphology with β-sheet structure. Moreover, the compressive stress and modulus of fibrous hydrogels were 31.9 ± 2.6 and 2.8 ± 0.8 kPa, respectively, which was formed using 2.0 wt.% concentration solutions. In addition, fibrous hydrogels supported BMSCs attachment and proliferation over 12 days. This study provides important insight in the in vitro processing of silk fibroin into useful new materials. - Highlights: • SF fibrous hydrogel was prepared by a novel two-step method. • SF solution containing nanofibrils in a range of tens to hundreds of nanometers was prepared. • Gelation process was top-down type gel with several minutes. • SF fibrous hydrogels exhibited nanofiber network morphology with β-sheet structure. • Fibrous hydrogels had higher compressive stresses superior to porous hydrogels.

  9. Two-step flash light sintering process for crack-free inkjet-printed Ag films

    International Nuclear Information System (INIS)

    Park, Sung-Hyeon; Kim, Hak-Sung; Jang, Shin; Lee, Dong-Jun; Oh, Jehoon

    2013-01-01

    In this paper, a two-step flash light sintering process for inkjet-printed Ag films is investigated with the aim of improving the quality of sintered Ag films. The flash light sintering process is divided into two steps: a preheating step and a main sintering step. The preheating step is used to remove the organic binder without abrupt vaporization. The main sintering step is used to complete the necking connections among the silver nanoparticles and achieve high electrical conductivity. The process minimizes the damage on the polymer substrate and the interface between the sintered Ag film and polymer substrate. The electrical conductivity is calculated by measuring the resistance and cross-sectional area with an LCR meter and 3D optical profiler, respectively. It is found that the resistivity of the optimal flash light-sintered Ag films (36.32 nΩ m), which is 228.86% of that of bulk silver, is lower than that of thermally sintered ones (40.84 nΩ m). Additionally, the polyimide film used as the substrate is preserved with the inkjet-printed pattern shape during the flash light sintering process without delamination or defects. (paper)

  10. Microstructural evolution of a superaustenitic stainless steel during a two-step deformation process

    Science.gov (United States)

    Bayat, N.; Ebrahimi, G. R.; Momeni, A.; Ezatpour, H. R.

    2018-02-01

    Single- and two-step hot compression experiments were carried out on 16Cr25Ni6Mo superaustenitic stainless steel in the temperature range from 950 to 1150°C and at a strain rate of 0.1 s-1. In the two-step tests, the first pass was interrupted at a strain of 0.2; after an interpass time of 5, 20, 40, 60, or 80 s, the test was resumed. The progress of dynamic recrystallization at the interruption strain was less than 10%. The static softening in the interpass period increased with increasing deformation temperature and increasing interpass time. The static recrystallization was found to be responsible for fast static softening in the temperature range from 950 to 1050°C. However, the gentle static softening at 1100 and 1150°C was attributed to the combination of static and metadynamic recrystallizations. The correlation between calculated fractional softening and microstructural observations showed that approximately 30% of interpass softening could be attributed to the static recovery. The microstructural observations illustrated the formation of fine recrystallized grains at the grain boundaries at longer interpass time. The Avrami kinetics equation was used to establish a relationship between the fractional softening and the interpass period. The activation energy for static softening was determined as 276 kJ/mol.

  11. One- or Two-Step Synthesis of C-8 and N-9 Substituted Purines.

    Science.gov (United States)

    Bollier, Mélanie; Klupsch, Frédérique; Six, Perrine; Dubuquoy, Laurent; Azaroual, Nathalie; Millet, Régis; Leleu-Chavain, Natascha

    2018-01-05

    A novel and original strategy to obtain rapidly a large diversity of C-8 and N-9 substituted purines was developed. The present procedure describes annulation reactions in one or two steps starting from 5-aminoimidazole-4-carbonitriles 1-8 in moderate to good yields. 8,9-Disubstituted-6,9-dihydro-1H-purin-6-ones 9-14, 6-amino-8,9-disubstituted-3,9-dihydro-2H-purin-2-ones 15-20, 8,9-disubstituted-3,9-dihydro-2H-purin-2,6-diamines 21-24 and 6-imino-1-phenyl-8,9-disubstituted-6,9-dihydro-1H-purin-2-(3H)-ones 25-26 were synthesized in one step using formic acid, urea, guanidine carbonate, and phenylisocyanate, respectively, whereas 8,9-disubstituted-9H-purin-6-amines 27-31 and 6-imino-8,9-disubstituted-6,9-dihydro-1H-purin-1-amines 32-33 were obtained in two steps using formamide and hydrazine, respectively.

  12. Efficient Hydrolysis of Rice Straw into Xylose and Glucose by a Two-step Process

    Directory of Open Access Journals (Sweden)

    YAN Lu-lu

    2016-07-01

    Full Text Available The hydrolysis of rice straw into xylose and glucose in dilute sulfuric acid aqueous solution was studied with a two-step process in batch autoclave reactor. The results showed that compared with the traditional one-step acid hydrolysis, both xylose and glucose could be produced in high yields from rice straw by using the two-step acid hydrolysis process. The effects of reaction temperature, reaction time, the amount of rice straw and acid concentration on the hydrolysis of rice straw were systematically studied, and showed that except initial rice straw loading amount, the other parameters had remarkable influence on the products distribution and yields. In the first-step of the hydrolysis process, a high xylose yield of 162.6 g·kg-1 was obtained at 140℃ after 120 min reaction time. When the solid residues from the first step were subjected to a second-step hydrolysis, a glucose yield as high as 216.5 g·kg-1 could be achieved at 180℃ after 120 min. This work provides a promising strategy for the efficient and value-added utilization of agricultural wastes such as rice straw.

  13. Preparation of biodiesel from waste cooking oil via two-step catalyzed process

    International Nuclear Information System (INIS)

    Wang Yong; Liu Pengzhan; Ou Shiyi; Zhang Zhisen

    2007-01-01

    Waste cooking oils (WCO), which contain large amounts of free fatty acids produced in restaurants, are collected by the environmental protection agency in the main cities of China and should be disposed in a suitable way. In this research, a two step catalyzed process was adopted to prepare biodiesel from waste cooking oil whose acid value was 75.92 ± 0.036 mgKOH/g. The free fatty acids of WCO were esterified with methanol catalyzed by ferric sulfate in the first step, and the triglycerides (TGs) in WCO were transesterified with methanol catalyzed by potassium hydroxide in the second step. The results showed that ferric sulfate had high activity to catalyze the esterification of free fatty acids (FFA) with methanol, The conversion rate of FFA reached 97.22% when 2 wt% of ferric sulfate was added to the reaction system containing methanol to TG in10:1 (mole ratio) composition and reacted at 95 deg. C for 4 h. The methanol was vacuum evaporated, and transesterification of the remained triglycerides was performed at 65 deg. C for 1 h in a reaction system containing 1 wt% of potassium hydroxide and 6:1 mole ratio of methanol to TG. The final product with 97.02% of biodiesel, obtained after the two step catalyzed process, was analyzed by gas chromatography. This new process has many advantages compared with the old processes, such as no acidic waste water, high efficiency, low equipment cost and easy recovery of the catalyst

  14. Two-Step Single Slope/SAR ADC with Error Correction for CMOS Image Sensor

    Directory of Open Access Journals (Sweden)

    Fang Tang

    2014-01-01

    Full Text Available Conventional two-step ADC for CMOS image sensor requires full resolution noise performance in the first stage single slope ADC, leading to high power consumption and large chip area. This paper presents an 11-bit two-step single slope/successive approximation register (SAR ADC scheme for CMOS image sensor applications. The first stage single slope ADC generates a 3-bit data and 1 redundant bit. The redundant bit is combined with the following 8-bit SAR ADC output code using a proposed error correction algorithm. Instead of requiring full resolution noise performance, the first stage single slope circuit of the proposed ADC can tolerate up to 3.125% quantization noise. With the proposed error correction mechanism, the power consumption and chip area of the single slope ADC are significantly reduced. The prototype ADC is fabricated using 0.18 μm CMOS technology. The chip area of the proposed ADC is 7 μm × 500 μm. The measurement results show that the energy efficiency figure-of-merit (FOM of the proposed ADC core is only 125 pJ/sample under 1.4 V power supply and the chip area efficiency is 84 k μm2·cycles/sample.

  15. Advanced Laser Architecture for Two-Step Laser Tandem Mass Spectrometer

    Science.gov (United States)

    Fahey, Molly E.; Li, Steven X.; Yu, Anthony W.; Getty, Stephanie A.

    2016-01-01

    Future astrobiology missions will focus on planets with significant astrochemical or potential astrobiological features, such as small, primitive bodies and the icy moons of the outer planets that may host diverse organic compounds. These missions require advanced instrument techniques to fully and unambiguously characterize the composition of surface and dust materials. Laser desorptionionization mass spectrometry (LDMS) is an emerging instrument technology for in situ mass analysis of non-volatile sample composition. A recent Goddard LDMS advancement is the two-step laser tandem mass spectrometer (L2MS) instrument to address the need for future flight instrumentation to deconvolve complex organic signatures. The L2MS prototype uses a resonance enhanced multi-photon laser ionization mechanism to selectively detect aromatic species from a more complex sample. By neglecting the aliphatic and inorganic mineral signatures in the two-step mass spectrum, the L2MS approach can provide both mass assignments and clues to structural information for an in situ investigation of non-volatile sample composition. In this paper we will describe our development effort on a new laser architecture that is based on the previously flown Lunar Orbiter Laser Altimeter (LOLA) laser transmitter for the L2MS instrument. The laser provides two discrete midinfrared wavelengths (2.8 m and 3.4 m) using monolithic optical parametric oscillators and ultraviolet (UV) wavelength (266 nm) on a single laser bench with a straightforward development path toward flight readiness.

  16. Obwegeser II osteotomy (transoral angle osteotomy) for open bite with skeletal class III deformity.

    Science.gov (United States)

    Kwon, Tae-Geon; Na, KwangMyung; Lee, Sang-Han

    2014-10-01

    This study evaluated postoperative stability after Obwegeser II osteotomy (transoral angle osteotomy, first reported by Obwegeser 1973) for severe open bite with mandibular prognathism. This retrospective study reviewed 20 consecutive patients who underwent only mandibular Obwegeser II osteotomy to correct open bite and mandibular prognathism. Lateral cephalograms were evaluated preoperatively (T1), immediate postoperatively (T2) and at least 6 months after the surgery (T3). Surgical and postsurgical changes in cephalometric measurements were evaluated statistically. Open bite with skeletal class III malocclusion was corrected by the Obwegeser II osteotomy alone. After an average of 9.9 ± 5.2 mm of mandibular setback with open bite closure (T2-T1, over-bite change, 5.7 ± 2.4 mm) by counter-clockwise rotation of the mandible, the patients showed 0.8 ± 1.7 mm of horizontal relapse (p > 0.05), 1.1 ± 1.7 mm of vertical relapse at the B point (p = 0.011) and -0.2 ± 1.6 mm of over-bite change postoperatively (T3-T2). With the adequate control of the condylar position with rigid internal fixation, Obwegeser II osteotomy showed acceptable stability after the correction of open bite with mandibular prognathism without a simultaneous maxillary osteotomy. An isolated Obwegeser II osteotomy can be considered a reliable option in cases with moderate to severe open bite with mandibular prognathism when the maxillary osteotomy is not needed if the patients have a well-positioned maxilla. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  17. Comparison of single-entry and double-entry two-step couple screening for cystic fibrosis carriers

    NARCIS (Netherlands)

    tenKate, LP; Verheij, JBGM; Wildhagen, MF; Hilderink, HBM; Kooij, L; Verzijl, JG; Habbema, JDF

    1996-01-01

    Both single-entry two-step (SETS) couple screening and double-entry two-step (DETS) couple screening have been recommended as methods to screen for cystic fibrosis gene carriers. In this paper we compare the expected results from both types of screening. In general, DETS results in a higher

  18. Two-step calibration method for multi-algorithm score-based face recognition systems by minimizing discrimination loss

    NARCIS (Netherlands)

    Susyanto, N.; Veldhuis, Raymond N.J.; Spreeuwers, Lieuwe Jan; Klaassen, C.A.J.

    2016-01-01

    We propose a new method for combining multi-algorithm score-based face recognition systems, which we call the two-step calibration method. Typically, algorithms for face recognition systems produce dependent scores. The two-step method is based on parametric copulas to handle this dependence. Its

  19. Two-step hydrothermal synthesis of Ru-Sn oxide composites for electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Chi-Chang; Chang, Kuo-Hsin; Wang, Chen-Ching [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi 621 (China)

    2007-03-20

    A two-step hydrothermal process was developed to synthesize hydrous 30RuO{sub 2}-70SnO{sub 2} composites with much better capacitive performances than those fabricated through the normal hydrothermal process, co-annealing method, or modified sol-gel procedure. A very high specific capacitance of RuO{sub 2} (C{sub S,Ru}), ca. 1150 F g{sup -1}, was obtained when this composite was synthesized via this two-step hydrothermal process with annealing in air at 150 C for 2 h. The voltammetric currents of this annealed composite were found to be quasi-linearly proportional to the scan rate of CV (up to 500 mV s{sup -1}), demonstrating its excellent power property. From Raman, UV-vis spectroscopic and TEM analyses, the reduction in mean particulate size is clearly found for this two-step oxide composite, attributable to the co-precipitation of (Ru{sub {delta}}Sn{sub 1-{delta}})O{sub 2}.xH{sub 2}O onto partially dissolved SnO{sub 2}.xH{sub 2}O and the formation of (Ru{sub {delta}}Sn{sub 1-{delta}})O{sub 2}.xH{sub 2}O crystallites in the second step. This effect significantly promotes the utilization of RuO{sub 2} (i.e., very high C{sub S,Ru}). The excellent capacitive performances, very similar to that of RuO{sub 2}.xH{sub 2}O, suggest the deposition of RuO{sub 2}-enriched (Ru{sub {delta}}Sn{sub 1-{delta}})O{sub 2}.xH{sub 2}O onto SnO{sub 2}.xH{sub 2}O seeds as well as the individual formation of (Ru{sub {delta}}Sn{sub 1-{delta}})O{sub 2}.xH{sub 2}O crystallites in the second hydrothermal step. (author)

  20. Xylose Isomerization with Zeolites in a Two-Step Alcohol–Water Process

    DEFF Research Database (Denmark)

    Paniagua, Marta; Shunmugavel, Saravanamurugan; Melián Rodriguez, Mayra

    2015-01-01

    xyluloside (step 1) followed by hydrolysis after water addition to form additional xylulose (step 2). NMR spectroscopy studies performed with 13C-labeled xylose confirmed the proposed reaction pathway. The most active catalyst examined was zeolite Y, which proved more active than zeolite beta, ZSM-5......, and mordenite. The yield of xylulose obtained over H-USY (Si/Al=6) after 1 h of reaction at 1008C was 39%. After water hydrolysis in the second reaction step, the yield increased to 47%. Results obtained from pyridine adsorption studies confirm that H-USY (6) is a catalyst that combines Brønsted and Lewis acid......Isomerization of xylose to xylulose was efficiently catalyzed by large-pore zeolites in a two-step methanol–water process that enhanced the product yield significantly. The reaction pathway involves xylose isomerization to xylulose, which, in part, subsequently reacts with methanol to form methyl...

  1. A two-step bioprocessing strategy in pentonic acids production from lignocellulosic pre-hydrolysate.

    Science.gov (United States)

    Zhou, Xin; Huang, Lu; Xu, Yong; Yu, Shiyuan

    2017-11-01

    Efficient utilization (over needless disposal) of biorefinery pre-hydrolysate is an economically relevant practice for improving biorefinery financial prospects. The liquid fraction obtained after acid hydrolysis pretreatment of lignocellulosic biomass, called pre-hydrolysate, are predominantly comprised of hemicellulosic carbohydrates. Using a two-step bioprocess, the hexoses were selectively fermented to ethanol by S. cerevisiae to clear the path for Gluconobacter oxydans transformation of pentoses to a high purity pentonic acids solution. Finally, approximately 180 g pentonic acids and 19 g ethanol could be produced starting from pre-hydrolysate produced from 1 kg corn stover. The results demonstrate execution of our objective to prove this bioconversion method for producing high purity pentonic acids starting from crude lignocellulosic pre-hydrolysate, a wastefully disregarded biorefinery process stream.

  2. Two-step controllable electrochemical etching of tungsten scanning probe microscopy tips

    KAUST Repository

    Khan, Yasser

    2012-01-01

    Dynamic electrochemical etching technique is optimized to produce tungsten tips with controllable shape and radius of curvature of less than 10 nm. Nascent features such as dynamic electrochemical etching and reverse biasing after drop-off are utilized, and two-step dynamic electrochemical etching is introduced to produce extremely sharp tips with controllable aspect ratio. Electronic current shut-off time for conventional dc drop-off technique is reduced to ?36 ns using high speed analog electronics. Undesirable variability in tip shape, which is innate to static dc electrochemical etching, is mitigated with novel dynamic electrochemical etching. Overall, we present a facile and robust approach, whereby using a novel etchant level adjustment mechanism, 30° variability in cone angle and 1.5 mm controllability in cone length were achieved, while routinely producing ultra-sharp probes. © 2012 American Institute of Physics.

  3. On analysis-based two-step interpolation methods for randomly sampled seismic data

    Science.gov (United States)

    Yang, Pengliang; Gao, Jinghuai; Chen, Wenchao

    2013-02-01

    Interpolating the missing traces of regularly or irregularly sampled seismic record is an exceedingly important issue in the geophysical community. Many modern acquisition and reconstruction methods are designed to exploit the transform domain sparsity of the few randomly recorded but informative seismic data using thresholding techniques. In this paper, to regularize randomly sampled seismic data, we introduce two accelerated, analysis-based two-step interpolation algorithms, the analysis-based FISTA (fast iterative shrinkage-thresholding algorithm) and the FPOCS (fast projection onto convex sets) algorithm from the IST (iterative shrinkage-thresholding) algorithm and the POCS (projection onto convex sets) algorithm. A MATLAB package is developed for the implementation of these thresholding-related interpolation methods. Based on this package, we compare the reconstruction performance of these algorithms, using synthetic and real seismic data. Combined with several thresholding strategies, the accelerated convergence of the proposed methods is also highlighted.

  4. Optical Properties of ZnO Nanowires and Nanorods Synthesized by Two Step Oxidation Process

    Directory of Open Access Journals (Sweden)

    Vahid ghafouri

    2013-12-01

    Full Text Available ZnO nanowires with a diameter of 70 nm and nanorods with a diameter in the range of 100-150 nm and two micrometer in length were grown on glass substrates by resistive evaporation method and applying a two step oxidation process at low temperatures, without using any catalyst, template or buffer layer. XRD pattern of these nanostructures indicated a good crystallinity property with wurtzite hexagonal structure. Photoluminescence measurement revealed three band emissions; one sharp strong peak in the UV region and two weaker peaks in the visible region, indicate good optical properties of nanorods synthesized by this method. Heat treatment in oxygen-rich atmosphere results to decrease of deep-level emission intensity in the PL spectra. The relatively high intensity of UV emission implies that this approach is a simple and promising method for fabricating ZnO nanorods in order to be used in optoelectronic devices especially in the UV range of the spectrum.

  5. Process Mining: A Two-Step Approach to Balance Between Underfitting and Overfitting

    DEFF Research Database (Denmark)

    van der Aalst, W.M.P.; Rubin, V.; Verbeek, H.M.W.

    behavior. At best, one has seen a representative subset. Therefore, classical synthesis techniques are not suitable as they aim at finding a model that is able to exactly reproduce the log. Existing process mining techniques try to avoid such "overfitting" by generalizing the model to allow for more...... support for it). None of the existing techniques enables the user to control the balance between "overfitting" and "underfitting". To address this, we propose a two-step approach. First, using a configurable approach, a transition system is constructed. Then, using the "theory of regions", the model...... is synthesized. The approach has been implemented in the context of ProM and overcomes many of the limitations of traditional approaches....

  6. Unusual inferior dislocation of shoulder: reduction by two-step maneuver: a case report

    Science.gov (United States)

    Saseendar, S; Agarwal, Dinesh K; Patro, Dilip K; Menon, Jagdish

    2009-01-01

    Dislocation of the shoulder is the commonest of all large joint dislocations. Inferior dislocation constitutes 0.5% of all shoulder dislocations. It characteristically presents with overhead abduction of the arm, the humerus being parallel to the spine of scapula. We present an unusual case of recurrent luxatio erecta in which the arm transformed later into an adducted position resembling the more common anterior shoulder dislocation. Such a case has not been described before in English literature. Closed reduction by the two-step maneuver was successful with a single attempt. MRI revealed posterior labral tear and a Hill-Sachs variant lesion on the superolateral aspect of humeral head. Immobilisation in a chest-arm bandage followed by physiotherapy yielded excellent results. The case is first of its kind; the unusual mechanism, unique radiological findings and alternate method of treatment are discussed. PMID:19883514

  7. A new two-step tuning procedure for a photocathode gun

    International Nuclear Information System (INIS)

    Lal, Shankar; Pant, K.K.; Krishnagopal, S.

    2008-01-01

    An important aspect of the development of multi-cell RF accelerating structures is tuning the resonant frequency f of the operating mode, field balance e b , and waveguide to cavity coupling coefficient β to the desired values. Earlier theoretical analyses have not been able to predict all three parameters simultaneously for a coupled-cavity system. We have developed a generalized circuit analysis to predict f, e b , and β of a coupled structure, based on the RF properties of the individual, uncoupled, cells. This has been used to develop a simplified two-step tuning procedure to tune a BNL/SLAC/UCLA type 1.6 cell S-band photocathode gun by varying RF properties of individual half and full cells, which are easily measurable. This procedure has been validated by tuning two true-to-scale prototypes made of aluminum and ETP copper to the desired values of the RF parameters

  8. Two-Step Beveled UWB Printed Monopole Antenna with Band Notch

    Directory of Open Access Journals (Sweden)

    Yan Xiao

    2014-01-01

    Full Text Available This paper presents a novel compact printed monopole ultra-wideband (UWB antenna featured with the band notch. The proposed antenna consists of a two-step beveled radiant patch and a truncated ground plane, which can provide a good impedance matching from 3.1 GHz to 10.6 GHz. In order to generate the band-notched characteristics, two symmetrical slots are embedded along with the microstrip feeding line, resulting in a band notch from 5.05 GHz to 5.85 GHz. Accordingly, the mutual electromagnetic interference between the UWB and wireless local area network (WLAN radio communication systems can be eliminated. In addition, it is shown how the slots integrated on the ground plane improve the radiation patterns. The experimental measurements are found to be in good agreement with the numerical simulations.

  9. Effects of loading sequence for notched specimens under high-low two-step fatigue loading

    Science.gov (United States)

    Crews, J. H., Jr.

    1971-01-01

    The effects of loading sequence on crack-initiation period were investigated for notched aluminum-alloy specimens under high-low two-step loading with special emphasis on local cyclic stresses and strains at the notch root. Local stress and strain were determined by a procedure based on an equation proposed by Neuber which relates elastoplastic stress and strain at a notch. Local stress and strain were also measured experimentally to verify the Neuber equation. The effects of initial high load on the crack-initiation periods were demonstrated with notched specimens and were simulated in unnotched specimens fatigue tested with local stress sequences. An analysis of the results indicated that sequence effects were not caused solely by local residual stresses, as is usually assumed; the existence of a damaging effect, resulting from the high local strain cycles, was demonstrated. The sequence effects observed with notched specimens were interpreted as the combined result of residual stresses and high local strain cycles.

  10. Structure of turbulent non-premixed flames modeled with two-step chemistry

    Science.gov (United States)

    Chen, J. H.; Mahalingam, S.; Puri, I. K.; Vervisch, L.

    1992-01-01

    Direct numerical simulations of turbulent diffusion flames modeled with finite-rate, two-step chemistry, A + B yields I, A + I yields P, were carried out. A detailed analysis of the turbulent flame structure reveals the complex nature of the penetration of various reactive species across two reaction zones in mixture fraction space. Due to this two zone structure, these flames were found to be robust, resisting extinction over the parameter ranges investigated. As in single-step computations, mixture fraction dissipation rate and the mixture fraction were found to be statistically correlated. Simulations involving unequal molecular diffusivities suggest that the small scale mixing process and, hence, the turbulent flame structure is sensitive to the Schmidt number.

  11. Chromosome image classification using a two-step probabilistic neural network

    Directory of Open Access Journals (Sweden)

    Sunthorn Rungruangbaiyok

    2010-07-01

    Full Text Available Chromosome image analysis is composed of image preparation, image analysis, and image diagnosis. General procedureof chromosome image analysis includes of image preprocessing in the first step, image segmentation, feature extraction, andimage classification in the last step. This paper presents the preliminary results that use probabilistic neural network toclassify chromosome image into 24 classes. Features of chromosome which were used in this paper are area, perimeter, band’sarea, singular value decomposition, and band profile. Chromosome images were grouped in two steps by probabilistic neuralnetwork. Six groups and twenty four groups are in the first and the second step, respectively. The result from the secondstep is twenty four chromosome classes. Density profile sampled at 10, 30, 50 and 80 were tested. The best classificationresult of female is 68.19% when density profile at 30 samples was used, and that of male is 61.30% when density profile at50 samples was used.

  12. Two-step freezing of hybridoma cells in 96-well microculture plates.

    Science.gov (United States)

    Pĕknicová, J; Kristofová, H

    1985-01-01

    Stabile hybridoma cells, colonies of hybridoma cells 14 days after fusion of immune spleen and myeloma cells, myeloma cells and fibroblasts cultured in 96-well microculture plates were frozen by the method of two-step freezing. The culture medium was aspirated, and 50 microliter of the medium containing a cryoprotectant (5% dimethyl sulphoxide) was added for 10 min at room temperature. The plates were put into microtene bags, placed at -25 degrees C in a freezer for 30 min and then stored at -100 degrees C in liquid nitrogen vapour. Plates with cells were thawed rapidly in a 50 degree C water bath. After thawing the hybrid cells were viable and continued to produce the specific antibody.

  13. Novel two-step synthesis of gold nanoparticles capped with bile acid conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Noponen, Virpi [University of Jyvaeskylae, Department of Chemistry, P.O. Box 35, FIN-40014 University of Jyvaeskylae (Finland); Bhat, Shreedhar [Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012 (India); Sievaenen, Elina [University of Jyvaeskylae, Department of Chemistry, P.O. Box 35, FIN-40014 University of Jyvaeskylae (Finland)], E-mail: elvirtan@jyu.fi; Kolehmainen, Erkki [University of Jyvaeskylae, Department of Chemistry, P.O. Box 35, FIN-40014 University of Jyvaeskylae (Finland)

    2008-08-01

    Bile acids and their conjugates are physiologically important molecules. Syntheses and structure elucidation combined with investigation of properties and applications of bile acids and their derivatives are of academic interest. The concept of using bile acids and their conjugates in nanoscience is a novel idea, which opens up fascinating prospects. In this article, an easy and simple route for obtaining N-lithocholyl-L-(cysteine ethyl ester) (3), capable of effectively capping and stabilizing metal nanoparticles, is described. The whole synthetic route needs only two steps giving a moderate to good yield. The gold NPs are characterized by elemental analysis, UV spectroscopy, and TEM. Additionally, {sup 13}C CP/MAS NMR studies for different ligand/Au ratios have been performed.

  14. Two-centre interference effects on the Thomas two-step scattering mechanisms

    International Nuclear Information System (INIS)

    Adivi, E Ghanbari

    2010-01-01

    The charge transfer process in the collision of fast protons with hydrogen molecules is theoretically investigated using the second-order Born approximation with correct boundary conditions. In addition to two first-order terms, the present calculations include the three second-order terms which correspond to the Thomas two-step scattering mechanisms. The interference effects, due to the scattering of the particles from two atomic centres, on the electron capture differential cross sections vary significantly with the orientation of the molecule and with the impact energy. After the averaging over all molecular orientations the interference patterns disappear but the Thomas peak becomes more pronounced. These patterns are also apparent in the differential cross sections as a function of the angle between the molecular axis and the incident beam direction. The integrated cross sections are calculated and the results are compared with available experimental data.

  15. TWO-STEP ALGORITHM OF TRAINING INITIALIZATION FOR ACOUSTIC MODELS BASED ON DEEP NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    I. P. Medennikov

    2016-03-01

    Full Text Available This paper presents a two-step initialization algorithm for training of acoustic models based on deep neural networks. The algorithm is focused on reducing the impact of the non-speech segments on the acoustic model training. The idea of the proposed algorithm is to reduce the percentage of non-speech examples in the training set. Effectiveness evaluation of the algorithm has been carried out on the example of English spontaneous telephone speech recognition (Switchboard. The application of the proposed algorithm has led to 3% relative word error rate reduction, compared with the training initialization by restricted Boltzmann machines. The results presented in the paper can be applied in the development of automatic speech recognition systems.

  16. Two step procedure for purification of enzymatically active prostate-specific antigen from seminal plasma.

    Science.gov (United States)

    Bindukumar, B; Kawinski, Elzbieta; Cherrin, Craig; Gambino, Leah M; Nair, Madhavan P N; Schwartz, Stanley A; Chadha, Kailash C

    2004-12-25

    The role of prostate-specific antigen (PSA) during the onset of prostate cancer and subsequent tumor growth and metastasis is not well understood. We have developed a simple two step procedure, based on principles of hydrophobic charge-induction chromatography and molecular size chromatography to provide pure free-PSA (f-PSA) preparation that is free from all other known PSA complexes as well as human kallikrein 2 (hK2). The overall recovery of f-PSA is 72%. The isolated f-PSA consists of three known isoforms that corresponds to pI of 6.2, 6.4 and 7.2. f-PSA is enzymatically active and its enzymatic activity can be effectively neutralized by a serine protease inhibitor.

  17. Characteristic analysis of laser isotope separation process by two-step photodissociation method

    International Nuclear Information System (INIS)

    Okamoto, Tsuyoshi; Suzuki, Atsuyuki; Kiyose, Ryohei

    1981-01-01

    A large number of laser isotope separation experiments have been performed actively in many countries. In this paper, the selective two-step photodissociation method is chosen and simultaneous nonlinear differential equations that express the separation process are solved directly by using computer. Predicted separation factors are investigated in relation to the incident pulse energy and the concentration of desired molecules. Furthermore, the concept of separative work is used to evaluate the results of separation for this method. It is shown from an example of numerical calculation that a very large separation factor can be obtained if the concentration of desired molecules is lowered and two laser pulses to be closely synchronized are not always required in operation for the photodissociation of molecules. (author)

  18. A two-step superplastic forging forming of semi-continuously cast AZ70 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Pan Wang

    2015-03-01

    Full Text Available A two-step technology combined forging with superplastic forming has been developed to enhance the forgeability of semi-continuously cast AZ70 magnesium alloy and realize the application of the as-cast magnesium alloy in large deformation bullet shell. In the first step, fine-grained microstructure preforms that are suitable for superplastic forming were obtained by reasonably designing the size of the initial blanks with the specific height-to-diameter ratio, upsetting the blanks and subsequent annealing. In the second step, the heat treated preforms were forged into the end products at the superplastic conditions. The end products exhibit high quality surface and satisfied microstructure. Consequently, this forming technology that not only avoids complicating the material preparation but also utilizes higher strain rate superplastic provides a near net-shaped novel method on magnesium forging forming technology using as-cast billet.

  19. Design scope and level for standard design certification under a two step licensing process

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Chang Wook; Suh, Nam Duk [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2012-08-15

    A small integral reactor SMART (System Integrated Modular Advanced ReacTor), being developed in Korea since late 1990s and targeted to obtaining a standard design approval by the end of 2011, is introduced. The design scope and level for design certification (DC) is well described in the U.S. NRC SECY documents published the early 1990s. However, the documents are valid for a one-step licensing process called a combined operating license (COL) by the U.S. NRC, while Korea still uses a two-step licensing process. Thus, referencing the concept of the SECY documents, we have established the design scope and level for the SMART DC using the contexts of the standard review plan (SRP). Some examples of the results and issues raised during our review are briefly presented in this paper. The same methodology will be applied to other types of reactor under development in Korea, such as future VHTR reactors.

  20. Unusual inferior dislocation of shoulder: reduction by two-step maneuver: a case report

    Directory of Open Access Journals (Sweden)

    Patro Dilip K

    2009-11-01

    Full Text Available Abstract Dislocation of the shoulder is the commonest of all large joint dislocations. Inferior dislocation constitutes 0.5% of all shoulder dislocations. It characteristically presents with overhead abduction of the arm, the humerus being parallel to the spine of scapula. We present an unusual case of recurrent luxatio erecta in which the arm transformed later into an adducted position resembling the more common anterior shoulder dislocation. Such a case has not been described before in English literature. Closed reduction by the two-step maneuver was successful with a single attempt. MRI revealed posterior labral tear and a Hill-Sachs variant lesion on the superolateral aspect of humeral head. Immobilisation in a chest-arm bandage followed by physiotherapy yielded excellent results. The case is first of its kind; the unusual mechanism, unique radiological findings and alternate method of treatment are discussed.

  1. A re-examination of two-step lateral stress history in silicon carbide

    International Nuclear Information System (INIS)

    Dandekar, Dattatraya P.

    2004-01-01

    The observed two-step lateral stress history in silicon carbide, SiC-B under plane shock wave propagation [N. K. Bourne, J. Millett, and I. Pickup, J. Appl. Phys. 81, 6019 (1997)] is attributed to a delayed failure in SiC-B due to propagation of a slow moving front traveling behind the main shock wave. According to this attribution, the first lower magnitude, step corresponds to the lateral stress in intact shock compressed silicon carbide as a result of the fast moving plane shock wave. The second step of higher magnitude, observed after a few hundred nanoseconds, corresponds to the lateral stress in failed silicon carbide due to propagation of the slower moving front. The current analysis, takes into account additional relevant existing results dealing with shock response of SiC-B, and shows that the suggested explanation for the observed phenomenon remains in doubt

  2. Two-step optimization of pressure and recovery of reverse osmosis desalination process.

    Science.gov (United States)

    Liang, Shuang; Liu, Cui; Song, Lianfa

    2009-05-01

    Driving pressure and recovery are two primary design variables of a reverse osmosis process that largely determine the total cost of seawater and brackish water desalination. A two-step optimization procedure was developed in this paper to determine the values of driving pressure and recovery that minimize the total cost of RO desalination. It was demonstrated that the optimal net driving pressure is solely determined by the electricity price and the membrane price index, which is a lumped parameter to collectively reflect membrane price, resistance, and service time. On the other hand, the optimal recovery is determined by the electricity price, initial osmotic pressure, and costs for pretreatment of raw water and handling of retentate. Concise equations were derived for the optimal net driving pressure and recovery. The dependences of the optimal net driving pressure and recovery on the electricity price, membrane price, and costs for raw water pretreatment and retentate handling were discussed.

  3. The face hallucinating two-step framework using hallucinated high-resolution residual

    Science.gov (United States)

    Naleer, H. M. M.; Lu, Yao; An, Yaozu

    2011-06-01

    In video surveillance, the attention human faces are frequently of small size. Image hallucination is an imperative factor disturbing the face classification by human and computer. In this paper, we propose a two-step face hallucination framework by means of training data sets which have a small quantity of low and high resolution images. In the first step, the global face is constructed based on optimal weights of training images. In the second step, a local residual compensation method bases on position patch via residual training face image data sets. Moreover, the hallucinated highresolution residual image which is obtained by the identical process can be subsequent for the local face. Finally, the hallucinated high-resolution residual image is appended with the input low-resolution face image which is interpolated to the high-resolution image dimension by an upsampling factor. Experiments fully demonstrate that our framework is very flexible and accomplishs good performance via small training data sets.

  4. SiO2 sol-gel films after ammonia and heat two-step treatments

    International Nuclear Information System (INIS)

    Zhang Chunlai; Wang Biyi; Tian Dongbin; Yin Wei; Jiang Xiaodong; Yuan Xiaodong; Yan Lianghong; Zhang Hongliang; Zhao Songnan; Lv Haibing

    2008-01-01

    SiO 2 thin films were deposited using tetraethoxylsilane as precursor, ammonia as catalyst on K9 glass by sol-gel method. These films were post-treated by ammonia and heat. The properties of the coatings were characterized by ellipsometer, UV-vis spectrophotometry, FTIR-spectroscopy, scanning probe microscope and contact angle measurement apparatus. The resuits indicate that the thickness of the films with ammonia and heat treatment tend to decrease. Both the refractive index and water contact angle increase after ammonia treatment. However, they both decrease after heat treatment. The former increases by 0.236 for the first step, then decreases by 0.202 for the second. The latter increases to 58.92 degree, then decreases to 38.07 degree. The transmittance of the coatings turn to be better and continuously shift to short wave by UV-vis spectrophotometry. The surface becomes smoother by AFM after the two-step treatment. (authors)

  5. A two-step mechanism for epigenetic specification of centromere identity and function.

    Science.gov (United States)

    Fachinetti, Daniele; Folco, H Diego; Nechemia-Arbely, Yael; Valente, Luis P; Nguyen, Kristen; Wong, Alex J; Zhu, Quan; Holland, Andrew J; Desai, Arshad; Jansen, Lars E T; Cleveland, Don W

    2013-09-01

    The basic determinant of chromosome inheritance, the centromere, is specified in many eukaryotes by an epigenetic mark. Using gene targeting in human cells and fission yeast, chromatin containing the centromere-specific histone H3 variant CENP-A is demonstrated to be the epigenetic mark that acts through a two-step mechanism to identify, maintain and propagate centromere function indefinitely. Initially, centromere position is replicated and maintained by chromatin assembled with the centromere-targeting domain (CATD) of CENP-A substituted into H3. Subsequently, nucleation of kinetochore assembly onto CATD-containing chromatin is shown to require either the amino- or carboxy-terminal tail of CENP-A for recruitment of inner kinetochore proteins, including stabilizing CENP-B binding to human centromeres or direct recruitment of CENP-C, respectively.

  6. Assessment of trochanteric osteotomy fragment union after acetabular fracture surgery.

    Science.gov (United States)

    Dubina, Andrew G; Wickramaratne, Niluka; O'Toole, Robert V; Manson, Theodore T

    2017-02-01

    Trochanteric osteotomies are performed in conjunction with standard approaches to improve surgical exposure during open reduction and internal fixation (ORIF) of acetabular fractures. The literature on total hip arthroplasty reports nonunion rates as high as 30% associated with trochanteric osteotomies; however, few data exist regarding the outcomes of trochanteric osteotomies for acetabular fracture surgery. Our hypotheses were 1) patients receiving trochanteric osteotomies during ORIF of acetabular fractures have a low rate of nonunion of the osteotomy fragment, and 2) hip abduction precautions are not necessary with digastric type osteotomies. A retrospective review was conducted to identify patients with acetabular fractures between July 2002 and June 2010 (n=734 fractures) who required trochanteric osteotomies (n=64, 9% of fractures). Forty-seven met inclusion criteria of adequate follow-up (>56days). No excluded patient experienced a complication. Fractures were classified using the Letournel-Judet classification system. Only seven (20%) of 35 patients who received digastric osteotomies had hip abduction precautions applied during the postoperative period. All study patients were shown to have radiographic union at the trochanteric osteotomy site (100% union rate, n=47). Hip abduction precautions intended to protect the osteotomy site and reduce the risk of nonunion and fixation failure were infrequently applied to patients with digastric osteotomies (20%) in this cohort. Multiple protective factors against nonunion were present in this study population compared with previous arthroplasty studies from other institutions. Trochanteric osteotomies are not associated with a significant nonunion rate, and digastric osteotomies might be safely managed without hip abduction precautions. Copyright © 2016. Published by Elsevier Ltd.

  7. Two-step quantum cutting efficiency in Pr3+-Yb3+ codoped KY3F10

    Science.gov (United States)

    Serrano, D.; Braud, A.; Doualan, J. L.; Bolaños, W.; Moncorgé, R.; Camy, P.

    2013-11-01

    The efficiency of a two-step quantum cutting (QC) mechanism for solar downconversion via two consecutive energy transfers from Pr3+ to Yb3+ is investigated in Pr3+-Yb3+ codoped KY3F10 crystals. The efficiency of the QC second energy transfer involving the Pr3+ (1G4) and Yb3+ (2F5/2) levels is particularly difficult to determine in a precise manner since these two levels are coupled by reciprocal energy transfer. We present a specific rate equation modeling that accurately describes Pr3+ and Yb3+ dynamics and intensity ratios measured as a function of the Yb3+ concentration. The modeling enables to calculate energy transfer rates for all the processes and shows the competition between the two-step QC mechanism and parasitic processes. The first-step of the QC mechanism is, as expected, particularly efficient reaching 96.9% and is not challenged by competing processes. The second step of the QC, while reaching an intrinsic efficiency of 75.9%, is plagued by backtransfers from Yb3+ (2F5/2) to Pr3+ (1G4) along with efficient concentration quenching mechanisms draining the Yb3+ excited-state. In addition, the investigation of intensity ratios with the Yb3+ concentration shows the importance of energy migration among Yb3+ ions that further enhances the detrimental effect of the Yb3+ quenching processes. As a result, the intrinsic QC efficiency (QCE) of the QC first and second energy transfers increases with the Yb3+ doping level up to 173% in KY3F10: 0.5%Pr3+-20%Yb3+, while the real QCE reduced by migration-assisted quenching processes is only 6.2% in this sample. These results clarify apparently conflicting reports found in the literature showing, on one hand, very high QCEs derived from spectroscopic experiments and, on the other hand, very low efficiency values obtained from integrating sphere measurements.

  8. Novel two-step derivation method for the synchronous analysis of inherited metabolic disorders using urine.

    Science.gov (United States)

    Sheng, Xiao-Qi; Wang, Yi-Chao

    2017-05-01

    The aim of the present study was to conduct preliminary clinical screening and monitoring using a novel two-step derivatization process of urine in five categories of inherited metabolic disease (IMD). Urine samples (100 µl, containing 2.5 mmol/l creatinine) were taken from patients with IMDs. The collected urine was then treated using a two-step derivatization method (with oximation and silylation at room temperature), where urea and protein were removed. In the first step of the derivatization, α-ketoacids and α-aldehyde acids were prepared by oximation using novel oximation reagents. The second-step of the derivatization was that residues were silylated for analysis. Urine samples were examined using gas chromatography/mass spectrometry (GC/MS) and a retention time-locking technique. The simultaneous analysis and identification of >400 metabolites in >130 types of IMD was possible from the GC/MS results, where the IMDs included phenylketonuria, ornithine transcarbamylase deficiency, neonatal intrahepatic cholestasis caused by citrin deficiency, β-ureidopropionase deficiency and mitochondrial metabolic disorders. This method was demonstrated to have good repeatability. Considering α-ketoglutarate (α-KG) as an example, the relative standard deviations (RSDs) of the α-KG retention time and peak area were 0.8 and 3.9%, respectively, the blank spiked recovery rate was between 89.6 and 99.8%, and the RSD was ≤7.5% (n=5). The method facilitates the analysis of thermally non-stable and semi-volatile metabolites in urine, and greatly expands the range of materials that can be synchronously screened by GC/MS. Furthermore, it provides a comprehensive, effective and reliable biochemical analysis platform for the pathological research of IMDs.

  9. Two-step delivery may avoid shoulder dystocia: head-to-body delivery interval is less important than we think.

    Science.gov (United States)

    Kotaska, Andrew; Campbell, Kim

    2014-08-01

    A belief that prolonged head-to-body delivery interval endangers the newborn underpins the common obstetrical practice of delivering the baby's trunk immediately after the head is born. Without intervention, however, birth typically occurs in two steps: once the fetal head is delivered there is usually a pause, and the rest of the infant is born with the next contraction. Allowing a two-step delivery does not increase the risk of fetal harm, and may lower the incidence of shoulder dystocia. A two-step approach to delivery should be considered physiologically normal. This has implications for the definition of shoulder dystocia.

  10. Severe gummy smile with class II malocclusion treated with LeFort I osteotomy combined with horseshoe osteotomy and intraoral vertical ramus osteotomy.

    Science.gov (United States)

    Shimo, Tsuyoshi; Nishiyama, Akiyoshi; Jinno, Tokiari; Sasaki, Akira

    2013-01-01

    In this article, we report the successful surgical treatment of a patient, 34 years of age, who had a severe gummy smile and a class II malocclusion. The patient had an 11-mm gingival exposure during full smile and a convex profile. A LeFort I osteotomy combined with a horseshoe osteotomy was used for the superior repositioning of the maxilla;then, an intraoral vertical ramus osteotomy (IVRO) and genioplasty were performed for mandibular advancement. The maxilla was acceptably impacted 8mm at the first incisor and 5mm at the first molar. Both the occlusion and facial appearance were significantly improved by this surgical-orthodontic treatment. Our results suggest that the combination of a horseshoe osteotomy with a LeFort I osteotomy is a useful technique for reliable superior repositioning of the maxilla.

  11. Open wedge metatarsal osteotomy versus crescentic osteotomy to correct severe hallux valgus deformity

    DEFF Research Database (Denmark)

    Wester, Jens Ulrik; Hamborg-Petersen, Ellen; Herold, Niels

    2016-01-01

    BACKGROUND: Different techniques of proximal osteotomies have been introduced to correct severe hallux valgus. The open wedge osteotomy is a newly introduced method for proximal osteotomy. The aim of this prospective randomized study was to compare the radiological and clinical results after...... operation for severe hallux valgus, comparing the open wedge osteotomy to the crescentic osteotomy which is our traditional treatment. METHODS: Forty-five patients with severe hallux valgus (hallux valgus angle >35̊, and intermetatarsal angle >15̊) were included in this study. The treatment was proximal...... and 12 months after the operation. RESULTS: In group 1 the hallux valgus angle decreased from 39.0̊ to 24.1̊ after 4 months and 27.9̊ after 12 months. In group 2 the angle decreased from 38.3̊ to 21.4̊ after 4 months and 27.0̊ after 12 months. The intermetatarsal angle in group 1 was 19.0̊ preoperatively...

  12. A permeation theory for single-file ion channels: one- and two-step models.

    Science.gov (United States)

    Nelson, Peter Hugo

    2011-04-28

    How many steps are required to model permeation through ion channels? This question is investigated by comparing one- and two-step models of permeation with experiment and MD simulation for the first time. In recent MD simulations, the observed permeation mechanism was identified as resembling a Hodgkin and Keynes knock-on mechanism with one voltage-dependent rate-determining step [Jensen et al., PNAS 107, 5833 (2010)]. These previously published simulation data are fitted to a one-step knock-on model that successfully explains the highly non-Ohmic current-voltage curve observed in the simulation. However, these predictions (and the simulations upon which they are based) are not representative of real channel behavior, which is typically Ohmic at low voltages. A two-step association/dissociation (A/D) model is then compared with experiment for the first time. This two-parameter model is shown to be remarkably consistent with previously published permeation experiments through the MaxiK potassium channel over a wide range of concentrations and positive voltages. The A/D model also provides a first-order explanation of permeation through the Shaker potassium channel, but it does not explain the asymmetry observed experimentally. To address this, a new asymmetric variant of the A/D model is developed using the present theoretical framework. It includes a third parameter that represents the value of the "permeation coordinate" (fractional electric potential energy) corresponding to the triply occupied state n of the channel. This asymmetric A/D model is fitted to published permeation data through the Shaker potassium channel at physiological concentrations, and it successfully predicts qualitative changes in the negative current-voltage data (including a transition to super-Ohmic behavior) based solely on a fit to positive-voltage data (that appear linear). The A/D model appears to be qualitatively consistent with a large group of published MD simulations, but no

  13. Two-step inversion with a logarithmic transformation for microwave breast imaging.

    Science.gov (United States)

    Meaney, Paul M; Geimer, Shireen D; Paulsen, Keith D

    2017-08-01

    The authors have developed a new two-step microwave tomographic image reconstruction process specifically designed to incorporate logarithmic transformed microwave imaging algorithms as a means of significantly improving spatial resolution and target property recovery. Log transform eliminates the need for a priori information, but spatial filtering often integrated as part of the regularization required to stabilize image recovery, generally smooths image features and reduces object definition. The new implementation begins with this smoothed image as the first step, but then utilizes it as the starting estimate for a second step which continues the iterative process with a standard weighted Euclidean distance regularization. The penalty term of the latter restricts the new image to a multi-dimensional location close to the original but allows the algorithm to optimize the image without excessive smoothing. The overall approach is based on a Gauss-Newton iterative scheme which incorporates a log transformation as a way of making the reconstruction more linear. It has been shown to be robust and not require a priori information as a condition for convergence, but does produce somewhat smoothed images as a result of associated regularization. The new two-step process utilizes the previous technique to generate a smoothed initial estimate and then uses the same reconstruction process with a weighted Euclidean distance penalty term. A simple and repeatable method has been implemented to determine the weighting factor without significant computational burden. The reconstructions are assessed according to conventional parameter estimation metrics. We apply the approach to phantom experiments using large, high contrast canonical shapes followed by a set of images recovered from an actual patient exam. The image improvements are substantial in regards to improved property recovery and feature delineation without inducing unwanted artifacts. Analysis of the residual vector

  14. Two-Step Forecast of Geomagnetic Storm Using Coronal Mass Ejection and Solar Wind Condition

    Science.gov (United States)

    Kim, R.-S.; Moon, Y.-J.; Gopalswamy, N.; Park, Y.-D.; Kim, Y.-H.

    2014-01-01

    To forecast geomagnetic storms, we had examined initially observed parameters of coronal mass ejections (CMEs) and introduced an empirical storm forecast model in a previous study. Now we suggest a two-step forecast considering not only CME parameters observed in the solar vicinity but also solar wind conditions near Earth to improve the forecast capability. We consider the empirical solar wind criteria derived in this study (Bz = -5 nT or Ey = 3 mV/m for t = 2 h for moderate storms with minimum Dst less than -50 nT) (i.e. Magnetic Field Magnitude, B (sub z) less than or equal to -5 nanoTeslas or duskward Electrical Field, E (sub y) greater than or equal to 3 millivolts per meter for time greater than or equal to 2 hours for moderate storms with Minimum Disturbance Storm Time, Dst less than -50 nanoTeslas) and a Dst model developed by Temerin and Li (2002, 2006) (TL [i.e. Temerin Li] model). Using 55 CME-Dst pairs during 1997 to 2003, our solar wind criteria produce slightly better forecasts for 31 storm events (90 percent) than the forecasts based on the TL model (87 percent). However, the latter produces better forecasts for 24 nonstorm events (88 percent), while the former correctly forecasts only 71 percent of them. We then performed the two-step forecast. The results are as follows: (i) for 15 events that are incorrectly forecasted using CME parameters, 12 cases (80 percent) can be properly predicted based on solar wind conditions; (ii) if we forecast a storm when both CME and solar wind conditions are satisfied (n, i.e. cap operator - the intersection set that is comprised of all the elements that are common to both), the critical success index becomes higher than that from the forecast using CME parameters alone, however, only 25 storm events (81 percent) are correctly forecasted; and (iii) if we forecast a storm when either set of these conditions is satisfied (?, i.e. cup operator - the union set that is comprised of all the elements of either or both

  15. On the two steps threshold selection for over-threshold modelling of extreme events

    Science.gov (United States)

    Bernardara, Pietro; Mazas, Franck; Weiss, Jerome; Andreewsky, Marc; Kergadallan, Xavier; Benoit, Michel; Hamm, Luc

    2013-04-01

    The estimation of the probability of occurrence of extreme events is traditionally achieved by fitting a probability distribution on a sample of extreme observations. In particular, the extreme value theory (EVT) states that values exceeding a given threshold converge through a Generalized Pareto Distribution (GPD) if the original sample is composed of independent and identically distributed values. However, the temporal series of sea and ocean variables usually show strong temporal autocorrelation. Traditionally, in order to select independent events for the following statistical analysis, the concept of a physical threshold is introduced: events that excess that threshold are defined as "extreme events". This is the so-called "Peak Over a Threshold (POT)" sampling, widely spread in the literature and currently used for engineering applications among many others. In the past, the threshold for the statistical sampling of extreme values asymptotically convergent toward GPD and the threshold for the physical selection of independent extreme events were confused, as the same threshold was used for both sampling data and to meet the hypothesis of extreme value convergence, leading to some incoherencies. In particular, if the two steps are performed simultaneously, the number of peaks over the threshold can increase but also decrease when the threshold decreases. This is logic in a physical point of view, since the definition of the sample of "extreme events" changes, but is not coherent with the statistical theory. We introduce a two-steps threshold selection for over-threshold modelling, aiming to discriminate (i) a physical threshold for the selection of extreme and independent events, and (ii) a statistical threshold for the optimization of the coherence with the hypothesis of the EVT. The former is a physical events identification procedure (also called "declustering") aiming at selecting independent extreme events. The latter is a purely statistical optimization

  16. Bilateral stress fractures of femoral neck in non-athletes: a report of four cases

    Directory of Open Access Journals (Sweden)

    Naik Monappa A

    2013-04-01

    Full Text Available 【Abstract】Femoral neck stress fractures (FNSFs are rare, constituting only 5% of all stress fractures in young adults. These fractures are usually seen in athletes, military recruits and patients with underlying metabolic diseases. The treatment of FNSFs is still controversial because of the inherent complications associated with the treatment procedure. We came across 4 cases of bilateral FNSFs in non-athletic individuals who were manual labourers with-out underlying bony disorders. Two patients with FNSFs and coxa vara deformity on both sides were managed by subtrochanteric valgus osteotomy and dynamic hip screw fixation. One of the remaining two patients was treated by cannulated cancellous screw fixation on one side and sub-trochanteric valgus osteotomy on the other side. The fourth patient received subtrochanteric valgus osteotomy on one side and bipolar hemiarthroplasty on the other side after failed cannulated screw fixation. All the fractures healed without any complications. No evidence of avascular ne-crosis or arthritis was noted in our series. Subtrochanteric valgus osteotomy restores normal neck-shaft angle in pa-tients suffering from FNSFs combined with coxa vara deformity. Moreover, it helps to bring the forces acting around the hip to normal biomechanical levels, leading to fracture union and better results. Replacement arthroplasty is recommended to patients who fail to achieve bony union after fixation. Key words: Fractures, stress; Femoral neck fractures; Coxa vara; Osteotomy

  17. Repair of femoral trochanteric osteotomy in the dog

    International Nuclear Information System (INIS)

    Whitelock, R.G.; Dyce, J.; Houlton, J.E.F.

    1997-01-01

    The records and radiographs of 24 dogs that underwent femoral trochanteric osteotomy repair were reviewed. Osteotomy repair was performed with either a pin and tension band wire or a lag screw technique. Significant clinical complications associated with the osteotomy were identified in one dog (4 per cent) six weeks after surgery, although abnormal radiographic changes were evident in 15 dogs (62 per cent). The method of repair did not influence healing and there were comparable radiographic complication rates. It is concluded that femoral trochanteric osteotomy is not associated with significant clinical problems, despite a high incidence of abnormal radiographic findings

  18. Outcome in corrective osteotomy for malunited distal radius fractures.

    Science.gov (United States)

    Samson, Lucjan; Treder, Mariusz; Kolarz, Krzysztof; Lorczyński, Adam

    2007-01-01

    This article reports outcome in osteotomy for malunion of distal radius fractures. We evaluated 12 patients with distal radius malunion (mean age 54), who were treated with corrective osteotomy. Wrist motion and grip strength were evaluated, along with examination of pre and post osteotomy radiographs. The indications for corrections were degree of deformity, limitation of function, pain, and the appearance of the wrist. The radiographic evaluation proved that the restoration of the normal anatomic relationship between the distal radius and ulna leads to significant improvement of the function of the hand, as measured by range of motion and grip strength. Osteotomy of the distal radius in cases of malunion gives favorable outcomes.

  19. Statistical optimization for biodiesel production from waste frying oil through two-step catalyzed process

    Energy Technology Data Exchange (ETDEWEB)

    Charoenchaitrakool, Manop [Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok (Thailand); Center for Advanced Studies in Nanotechnology and its Applications in Chemical, Food and Agricultural Industries, Kasetsart University, Bangkok (Thailand); Thienmethangkoon, Juthagate [Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok (Thailand)

    2011-01-15

    The aim of this work was to investigate the optimum conditions in biodiesel production from waste frying oil using two-step catalyzed process. In the first step, sulfuric acid was used as a catalyst for the esterification reaction of free fatty acid and methanol in order to reduce the free fatty acid content to be approximate 0.5%. In the second step, the product from the first step was further reacted with methanol using potassium hydroxide as a catalyst. The Box-Behnken design of experiment was carried out using the MINITAB RELEASE 14, and the results were analyzed using response surface methodology. The optimum conditions for biodiesel production were obtained when using methanol to oil molar ratio of 6.1:1, 0.68 wt.% of sulfuric acid, at 51 C with a reaction time of 60 min in the first step, followed by using molar ratio of methanol to product from the first step of 9.1:1, 1 wt.% KOH, at 55 C with a reaction time of 60 min in the second step. The percentage of methyl ester in the obtained product was 90.56 {+-} 0.28%. In addition, the fuel properties of the produced biodiesel were in the acceptable ranges according to Thai standard for community biodiesel. (author)

  20. A two-step computer-assisted method for deriving steady-state rate equations.

    Science.gov (United States)

    Fromm, S J; Fromm, H J

    1999-11-19

    A number of computer-assisted methods have been described for the derivation of enzyme-catalyzed steady-state rate equations [K. R. Runyan and R. B. Gunn (1989) Methods Enzymol. 171, 164-190; R. Varon, F. Garcia-Seville, M. Garvia-Moreno, F. Garcia-Canovas, R. Peyro, and R. G. Duggleby (1997) Comput. Appl. Biosci. 13, 159-167]; however, the required programs are either not readily available or require special software. We present here a two-step computer-assisted procedure for deriving steady-state rate equations using the widely available program Mathematica. In the first step, the differential equations for a particular kinetic mechanism that describe changes in enzyme concentration as a function of time are set equal to zero and entered into Mathematica in matrix form. In the second step, a single command allows for the computation of the distribution equations for the free enzyme and each enzyme-ligand complex. Copyright 1999 Academic Press.

  1. A Novel Two-Step Method for Fabricating Silver Plating Cotton Fabrics

    Directory of Open Access Journals (Sweden)

    Hao Liu

    2016-01-01

    Full Text Available A novel two-step method was presented for fabricating silver plating cotton fabrics (SPCFs with high electrical conductivity and excellent washing fastness. First, polydopamine (PDA film was coated on the surface of cotton fabrics by in situ polymerization of dopamine, the silver ions in silver nitrate solution were reduced by the catechol groups of polydopamine, and silver nanoparticles were combined with polydopamine by covalent bond on the surface of cotton fabrics. Second, silver ions were reduced by glucose, and silver plating was coated on the surface. Subsequently, the properties of SPCFs were characterized by field emission scanning electron microscopy (FESEM, X-ray photoelectron spectroscopy (XPS and thermogravimetric analysis (TGA, and so forth. With the increasing of silver-ammonia solution concentration or dopamine concentration, the surface resistivity of SPCFs decreases and gradually stabilized. The surface resistivity of the SPCFs can reach 0.12±0.02 Ω, and electromagnetic shielding effectiveness (ESE of the SPCFs can reach 58.5±4.5 dB. Conductive fabrics have wide application prospect in many of fields, such as antibacterial, intelligent textiles, smart garments, electromagnetic shielding, and flexible sensors.

  2. Heavy mesons in a simple quark-confining two-step potential model

    International Nuclear Information System (INIS)

    Kulshreshtha, D.S.; Kaushal, R.S.

    1980-10-01

    We study the mass spectra and decay widths of upsilon resonances in a simple quark-confining, analytically solvable, two-step potential model used earlier to study the charmonium system and even the light mesons like π, rho, K,... etc. Results are found to be in good agreement with experiments and also with the values predicted by others. We also calculate within our model, the masses of the lowest-lying bottom mesons which we denote by B(π) or B, B(rho) or Bsup(*), B(K) or Bsub(s), B(Ksup(*)) or Bsub(s)sup(*) and B(psi) or Bsub(c); showing that these agree well with the other theoretical predictions. In this way we put the BB-bar threshold at 10.242 GeV, which means in our model the first three radial upsilon excitations, viz. Y(9.4345), Y'(9.9930) and Y''(10.1988) are stable with respect to the Zweig allowed decay Ysup(|||...) → B-barB. (author)

  3. CALB-Catalyzed Two-Step Alcoholytic Desymmetrization of 3-Methylglutaric Diazolides in MTBE.

    Science.gov (United States)

    Wu, Ting-Yi; Lai, Yuan-Rong; Tsai, Shau-Wei

    2017-12-15

    Optically pure 3-substituted glutarates can be prepared from the alcoholic ring-opening of cyclic anhydride derivatives, esterification of 3-substituted glutaric acid, and hydrolysis, alcoholysis, aminolysis, and ammonolysis of the diester derivatives via hydrolases or organocatalysts. Unfortunately, most of them mainly focus on the first-step desymmetrization, leading to the difficulty on producing optically pure enantiomers. As a general trend in lipase-catalyzed desymmetrization of 3-methylglutarates, poorer enantiomeric excesses with lower chemical yields were found, as the methyl substituent is relatively small to induce a high enzyme stereodiscrimination. The two-step desymmetrization for CALB-catalyzed alcoholysis of 3-methylglutaric di-1,2,4-triazolide 1a in anhydrous MTBE is first developed to increase the enzyme activity in each reaction step. The enantioselectivity for the second-step kinetic resolution is furthermore improved by using 3-methylglutaric dipyrazolide 1b as the substrate. The kinetic and thermodynamic analysis is, moreover, addressed for shedding insights into the desymmetrization process.

  4. Two-Step Laser Ranging for Precise Tracking of a Spacecraft

    Science.gov (United States)

    Chui, Talso; Penanen, Konstantin

    2005-01-01

    A document proposes a two-step laser ranging technique for precise tracking of a coasting interplanetary spacecraft to determine the degree to which leakage of fuel, solar wind, and/or solar-radiation pressure causes it to deviate from a purely gravitational trajectory. Such a determination could contribute to the precision of a test of a theory of gravitation. In the technique, a proof mass would be released from the spacecraft. By use of laser ranging equipment on the spacecraft and retroreflectors attached to the proof mass, the relative position of the spacecraft and proof mass would be determined. Meanwhile, the position of the spacecraft relative to the Earth would be determined by ranging by use of a laser transponder. The vector sum of the two sets of ranging measurements would be the position of the proof mass relative to the Earth. Unlike the acceleration of the spacecraft, the acceleration of the proof mass should not include a residual component attributable to leakage of fuel. In addition, the effects of solar radiation and solar wind on the proof mass could be minimized by releasing the proof mass into the shadow of the spacecraft.

  5. Mother Vocal Recognition in Antarctic Fur Seal Arctocephalus gazella Pups: A Two-Step Process.

    Directory of Open Access Journals (Sweden)

    Thierry Aubin

    Full Text Available In otariids, mother's recognition by pups is essential to their survival since females nurse exclusively their own young and can be very aggressive towards non-kin. Antarctic fur seal, Arctocephalus gazella, come ashore to breed and form dense colonies. During the 4-month lactation period, females alternate foraging trips at sea with suckling period ashore. On each return to the colony, females and pups first use vocalizations to find each other among several hundred conspecifics and olfaction is used as a final check. Such vocal identification has to be highly efficient. In this present study, we investigated the components of the individual vocal signature used by pups to identify their mothers by performing playback experiments on pups with synthetic signals. We thus tested the efficiency of this individual vocal signature by performing propagation tests and by testing pups at different playback distances. Pups use both amplitude and frequency modulations to identify their mother's voice, as well as the energy spectrum. Propagation tests showed that frequency modulations propagated reliably up to 64m, whereas amplitude modulations and spectral content greatly were highly degraded for distances over 8m. Playback on pups at different distances suggested that the individual identification is a two-step process: at long range, pups identified first the frequency modulation pattern of their mother's calls, and other components of the vocal signature at closer range. The individual vocal recognition system developed by Antarctic fur seals is well adapted to face the main constraint of finding kin in a crowd.

  6. Kinetic analysis on the two-step processes of AOB and NOB in aerobic nitrifying granules.

    Science.gov (United States)

    Fang, Fang; Ni, Bing-Jie; Li, Xiao-Yan; Sheng, Guo-Ping; Yu, Han-Qing

    2009-07-01

    Complete granulation of nitrifying sludge was achieved in a sequencing batch reactor. For the granular sludge, batch experiments were conducted to characterize the kinetic features of ammonia oxidizers (AOB) and nitrite oxidizers (NOB) in the granules using the respirometric method. A two-step nitrification model was established to determine the kinetic parameters of both AOB and NOB. In addition to nitrification reactions, the new model also took into account biomass maintenance and mass transfer through the granules. The yield coefficient, maximum specific growth rate, and affinity constant for ammonium for AOB were 0.21 g chemical oxygen demand (COD) g(-1) N, 0.09 h(-1), and 9.1 mg N L(-1), respectively, whereas the corresponding values for NOB were 0.05 g COD g(-1) N, 0.11 h(-1), and 4.85 mg N L(-1), respectively. The model developed in this study performed well in simulating the oxygen uptake rate and nitrogen conversion kinetics and in predicting the oxygen consumption of the AOB and NOB in aerobic granules.

  7. Biodiesel production from microalgae Spirulina maxima by two step process: Optimization of process variable

    Directory of Open Access Journals (Sweden)

    M.A. Rahman

    2017-04-01

    Full Text Available Biodiesel from green energy source is gaining tremendous attention for ecofriendly and economically aspect. In this investigation, a two-step process was developed for the production of biodiesel from microalgae Spirulina maxima and determined best operating conditions for the steps. In the first stage, acid esterification was conducted to lessen acid value (AV from 10.66 to 0.51 mgKOH/g of the feedstock and optimal conditions for maximum esterified oil yielding were found at molar ratio 12:1, temperature 60°C, 1% (wt% H2SO4, and mixing intensity 400 rpm for a reaction time of 90 min. The second stage alkali transesterification was carried out for maximum biodiesel yielding (86.1% and optimal conditions were found at molar ratio 9:1, temperature 65°C, mixing intensity 600 rpm, catalyst concentration 0.75% (wt% KOH for a reaction time of 20 min. Biodiesel were analyzed according to ASTM standards and results were within standards limit. Results will helpful to produce third generation algal biodiesel from microalgae Spirulina maxima in an efficient manner.

  8. Time ordering of two-step processes in energetic ion-atom collisions: Basic formalism

    International Nuclear Information System (INIS)

    Stolterfoht, N.

    1993-01-01

    The semiclassical approximation is applied in second order to describe time ordering of two-step processes in energetic ion-atom collisions. Emphasis is given to the conditions for interferences between first- and second-order terms. In systems with two active electrons, time ordering gives rise to a pair of associated paths involving a second-order process and its time-inverted process. Combining these paths within the independent-particle frozen orbital model, time ordering is lost. It is shown that the loss of time ordering modifies the second-order amplitude so that its ability to interfere with the first-order amplitude is essentially reduced. Time ordering and the capability for interference is regained, as one path is blocked by means of the Pauli exclusion principle. The time-ordering formalism is prepared for papers dealing with collision experiments of single excitation [Stolterfoht et al., following paper, Phys. Rev. A 48, 2986 (1993)] and double excitation [Stolterfoht et al. (unpublished)

  9. A two-step FEM-SEM approach for wave propagation analysis in cable structures

    Science.gov (United States)

    Zhang, Songhan; Shen, Ruili; Wang, Tao; De Roeck, Guido; Lombaert, Geert

    2018-02-01

    Vibration-based methods are among the most widely studied in structural health monitoring (SHM). It is well known, however, that the low-order modes, characterizing the global dynamic behaviour of structures, are relatively insensitive to local damage. Such local damage may be easier to detect by methods based on wave propagation which involve local high frequency behaviour. The present work considers the numerical analysis of wave propagation in cables. A two-step approach is proposed which allows taking into account the cable sag and the distribution of the axial forces in the wave propagation analysis. In the first step, the static deformation and internal forces are obtained by the finite element method (FEM), taking into account geometric nonlinear effects. In the second step, the results from the static analysis are used to define the initial state of the dynamic analysis which is performed by means of the spectral element method (SEM). The use of the SEM in the second step of the analysis allows for a significant reduction in computational costs as compared to a FE analysis. This methodology is first verified by means of a full FE analysis for a single stretched cable. Next, simulations are made to study the effects of damage in a single stretched cable and a cable-supported truss. The results of the simulations show how damage significantly affects the high frequency response, confirming the potential of wave propagation based methods for SHM.

  10. A two-step method for the extraction of high-quality RNA from endoscopic biopsies.

    Science.gov (United States)

    Wex, Thomas; Treiber, Gerhard; Lendeckel, Uwe; Malfertheiner, Peter

    2003-08-01

    The use of molecular techniques such as quantitative RT-PCR depends on the quality of cellular RNA. In particular, RNA extraction from endoscopic biopsies is difficult with respect to yield, and especially integrity. Endoscopic biopsies taken from the gastric antrum, corpus and duodenum were subjected to various RNA extraction protocols, and the RNA was used for quantitative RT-PCR. The subsequent use of two methods, (i) a phenol/chloroform extraction and (ii) a column-based extraction method, resulted in a yield of 4.5 microg total RNA per biopsy with reliable quality in 80% of samples. The quantitative RT-PCR analysis revealed that only RNA samples that clearly show both 18S- and 28S-RNA bands in agarose gel electrophoresis were suitable for quantitative RT-PCR as shown by expression of corpus-specific pepsinogen C-mRNA and the duodenum-specific multi-drug resistance protein-1 (mdr-1)-mRNA. In partially degraded RNA, pepsinogen C, mdr-1, or beta-actin mRNAs were still detectable, but the quantitative determination gave inconsistent data. The two-step method described here is a suitable option for extracting high-quality RNA from endoscopic biopsies when other standard protocols fail.

  11. Electrohydraulic linear actuator with two stepping motors controlled by overshoot-free algorithm

    Science.gov (United States)

    Milecki, Andrzej; Ortmann, Jarosław

    2017-11-01

    The paper describes electrohydraulic spool valves with stepping motors used as electromechanical transducers. A new concept of a proportional valve in which two stepping motors are working differentially is introduced. Such valve changes the fluid flow proportionally to the sum or difference of the motors' steps numbers. The valve design and principle of its operation is described. Theoretical equations and simulation models are proposed for all elements of the drive, i.e., the stepping motor units, hydraulic valve and cylinder. The main features of the valve and drive operation are described; some specific problem areas covering the nature of stepping motors and their differential work in the valve are also considered. The whole servo drive non-linear model is proposed and used further for simulation investigations. The initial simulation investigations of the drive with a new valve have shown that there is a significant overshoot in the drive step response, which is not allowed in positioning process. Therefore additional effort is spent to reduce the overshoot and in consequence reduce the settling time. A special predictive algorithm is proposed to this end. Then the proposed control method is tested and further improved in simulations. Further on, the model is implemented in reality and the whole servo drive system is tested. The investigation results presented in this paper, are showing an overshoot-free positioning process which enables high positioning accuracy.

  12. Photocatalytically active Au/TiO2 films deposited by two-step spray pyrolysis

    International Nuclear Information System (INIS)

    Balashev, Konstantin; Georgiev, Petar; Simeonova, Sylvia; Stambolova, Irina; Blaskov, Vladimir; Vassilev, Sasho; Eliyas, Alexander

    2016-01-01

    Nanocrystalline TiO 2 and surface gold-modified films (Au/TiO 2 ) are obtained by two step spray pyrolysis process. Titanium tetrachloride (TiCl 4 ) was used as inorganic titanium precursor. The Au nanoparticles were deposited on the surface of sprayed TiO 2 films, obtained by the classical Turkevich method. The AFM analyses have revealed that the roughness of Au/TiO 2 is twice lower than that of the reference titania film. Some globular species are visible on the surface, which could be either individual Au nanoparticles or Au nanoparticles’ agglomerates embedded into the TiO 2 film. The photocatalytic activity in the oxidative degradation of Reactive Black 5 dye under visible light of the Au/TiO 2 films was estimated in a semi-batch reactor. Surface gold modified TiO 2 films revealed higher photocatalytic efficiency than the reference sample. Key words: Au nanoparticles, photocatalysis, azo dye, titania, nanosized

  13. Biodiesel from dewatered wastewater sludge: a two-step process for a more advantageous production.

    Science.gov (United States)

    Pastore, Carlo; Lopez, Antonio; Lotito, Vincenzo; Mascolo, Giuseppe

    2013-07-01

    Alternative approaches for obtaining biodiesel from municipal sludge have been successfully investigated. In order to avoid the expensive conventional preliminary step of sludge drying, dewatered sludge (TSS: 15wt%) was used as starting material. The best performance in terms of yield of fatty acid methyl esters (18wt%) with the lowest energy demand (17MJkgFAME(-1)) was obtained by a new two-step approach based on hexane extraction carried out directly on dewatered acidified (H2SO4) sludge followed by methanolysis of extracted lipids. It was found that sulphuric acid plays a key role in the whole process not only for the transesterification of glycerides but also for the production of new free fatty acids from soaps and their esterification with methanol. In addition to biodiesel production, the investigated process allows valorization of primary sludge as it turns it into a valuable source of chemicals, namely sterols (2.5wt%), aliphatic alcohols (0.8wt%) and waxes (2.3wt%). Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Two-steps microwave-assisted treatment on acid hydrolysis of sago pith for bioethanol production

    Science.gov (United States)

    Sunarti, T. C.; Yanti, S. D.; Ruriani, E.

    2017-05-01

    Sago is a genus of palm that can be utilized to produce fermentable sugars as substrate for bioethanol. Sago pith is a heterogeneous substrate consists of starch and fiber. Acid hydrolysis by microwave heating radiation can break down starch and fibers together in a very short time, so it is considered to be very efficient process. The use of microwave energy (as power level) and variation of heating time can produce fermentable sugar with certain characteristics. This study included the preparation and analysis of sago pith flour; process of acid hydrolysis (0.3 M and 0.5 M H2SO4) using two steps microwave heating, first with power level 30% (1, 2 and 3 min) and second with power level 70% (3 min); and ethanol production. The conventional treatment (autoclaving at 121°C for 15 min) was carried for the comparison. The highest fermentable sugar (105.7 g/l) was resulted from microwave heating with power level 30% for 2 min followed by the power level 70% for 3 min. This hydrolyzate then used as substrate for bioethanol fermentation and partially neutralized (pH 3, 4, 5) by using yeast Issatchenkia orientalis, and the highest ethanol (2.8 g/l) was produced in pH 5.

  15. A Two-Step Hybrid Approach for Modeling the Nonlinear Dynamic Response of Piezoelectric Energy Harvesters

    Directory of Open Access Journals (Sweden)

    Claudio Maruccio

    2018-01-01

    Full Text Available An effective hybrid computational framework is described here in order to assess the nonlinear dynamic response of piezoelectric energy harvesting devices. The proposed strategy basically consists of two steps. First, fully coupled multiphysics finite element (FE analyses are performed to evaluate the nonlinear static response of the device. An enhanced reduced-order model is then derived, where the global dynamic response is formulated in the state-space using lumped coefficients enriched with the information derived from the FE simulations. The electromechanical response of piezoelectric beams under forced vibrations is studied by means of the proposed approach, which is also validated by comparing numerical predictions with some experimental results. Such numerical and experimental investigations have been carried out with the main aim of studying the influence of material and geometrical parameters on the global nonlinear response. The advantage of the presented approach is that the overall computational and experimental efforts are significantly reduced while preserving a satisfactory accuracy in the assessment of the global behavior.

  16. Two-step technique for posterior optic buttonholing of intraocular lens.

    Science.gov (United States)

    Agarwal, Tushar; Jhanji, Vishal; Singh, Digvijay; Khokhar, Sudarshan

    2014-04-01

    This study aims to describe a two-step surgical technique for placement of a posterior chamber intraocular lens (IOL) in cases with crystalline lens subluxation resulting from non-progressive zonular dialysis. The first stage entails a phacoemulsification with creation of a 4-mm posterior capsular opening using an automated vitrector. The second stage performed 6 weeks later includes an anterior vitrectomy and injection of a foldable three-piece IOL in the sulcus. The haptics of IOL are positioned in the sulcus while the optic is pushed behind the posterior capsular opening therefore "buttonholing" the IOL. Seven eyes of seven patients with posttraumatic zonular dialysis were operated using this technique. Follow-up of all cases revealed a well-centered IOL with good postoperative visual acuity (20/20 to 20/80). Our two-stage surgical technique precludes the insertion of capsular tension ring in cases with non-progressive zonular dialysis. The technique is recommended in the presence of less than or equal to 6 clock hours of zonular dialysis with preexisting posterior capsular tear or herniation of vitreous in the anterior chamber.

  17. Two-Step Time of Arrival Estimation for Pulse-Based Ultra-Wideband Systems

    Directory of Open Access Journals (Sweden)

    H. Vincent Poor

    2008-05-01

    Full Text Available In cooperative localization systems, wireless nodes need to exchange accurate position-related information such as time-of-arrival (TOA and angle-of-arrival (AOA, in order to obtain accurate location information. One alternative for providing accurate position-related information is to use ultra-wideband (UWB signals. The high time resolution of UWB signals presents a potential for very accurate positioning based on TOA estimation. However, it is challenging to realize very accurate positioning systems in practical scenarios, due to both complexity/cost constraints and adverse channel conditions such as multipath propagation. In this paper, a two-step TOA estimation algorithm is proposed for UWB systems in order to provide accurate TOA estimation under practical constraints. In order to speed up the estimation process, the first step estimates a coarse TOA of the received signal based on received signal energy. Then, in the second step, the arrival time of the first signal path is estimated by considering a hypothesis testing approach. The proposed scheme uses low-rate correlation outputs and is able to perform accurate TOA estimation in reasonable time intervals. The simulation results are presented to analyze the performance of the estimator.

  18. Availability of the Two-step Test to evaluate balance in frail people in a day care service.

    Science.gov (United States)

    Kojima, Kazunori; Kamai, Daisuke; Ishitani, Shogo; Watanabe, Susumu

    2017-06-01

    [Purpose] This study evaluated balance tests in users of a day care service who needed nursing care or support, and investigated the usefulness of the Two-step Test for evaluating balance. [Subjects and Methods] The subjects were users of a day care service, and had certified need for long-term care or support. All subjects were able to undergo the balance evaluations. Balance tests included the 3-m Timed Up and Go test (TUG), the one-leg standing time, and the Two-step Test. [Results] The Two-step Test and other balance tests were strongly correlated. [Conclusion] In this study of subjects who needed nursing care or support, the results were the same as in a previous study of subjects who did not need nursing care or support. The Two-step Test should be considered as an indicator of balance ability in elderly individuals requiring nursing care or support.

  19. Instrumentation failure following pedicle subtraction osteotomy: the role of rod material, diameter, and multi-rod constructs.

    Science.gov (United States)

    Luca, Andrea; Ottardi, Claudia; Sasso, Maurizio; Prosdocimo, Liliana; La Barbera, Luigi; Brayda-Bruno, Marco; Galbusera, Fabio; Villa, Tomaso

    2017-03-01

    Pedicle subtraction osteotomy (PSO) has a complication rate noticeably higher than other corrective surgical techniques used for the treatment of spinal sagittal imbalance. In particular, rod breakage and pseudoarthrosis remain burning issues of this technique. Goal of this study was to investigate the biomechanical performance of several hardware constructs. The study was performed using two validated finite element models of the lumbosacral spine (L1-S1) incorporating a PSO on L3 and L4, respectively. Both models were instrumented two levels above and below the osteotomy site. Different combinations of materials (Ti6Al4V and Cr-Co) and device configurations (bilateral single vs. double rod, rod diameters of 5 and 6 mm) were investigated. The loading was represented considering a force of 500 N (imposed along the spinal curvature and connecting the vertebral bodies) and pure moments of 7.5 Nm in flexion-extension, lateral bending and axial rotation. The results were evaluated in terms of range of motion (ROM), load, and stresses acting on the instrumentation. A comparable ROM was found for all the models. The simulations showed a different behavior of the devices: increasing the stiffness an 8-19% increase of the load was calculated on the rod. However, the stress on the instrumentation resulted higher on Cr-Co devices and on smaller rods. The highest stress reduction (up to 50%) was ensured using double rod constructs. The bilateral double parallel rods configuration resulted the best to reduce the stresses on the spinal fixators at the osteotomy site. However, the high loads acting on the rods with respect to the physiologic condition could slow down the bone healing at the osteotomy site.

  20. Modified french osteotomy for cubitus varus deformity

    International Nuclear Information System (INIS)

    Ahmad, I.; Idrees, M.

    2007-01-01

    To evaluate the outcome of Modified French Osteotomy for correction of cubitus varus deformity. All children, aged 3-12 years, with cubitus varus deformity were included in the study. Pre-operative clinical as well as radiological assessment of upper extremities were done in all cases. Modified French osteotomy was done to correct the deformity. All patients were followed for seven months. Physical examination for the range of motion, scar and post-operative complications were assessed. Antero-posterior and lateral radiographs of the elbow were obtained, and the carrying angles and lateral condylar prominence index were measured and recorded. Out of the total 30 patients, 26 were male and four female. Left side was involved in 24 cases and the right side in six. The average age at the time of osteotomy was seven years (range 3.5-12 years). The average pre-operative carrying angle was 25.2 degree (range 18-30 degree) and the post-operative angle 8.7 degree (range 5-13 degree valgus). The average pre- operative range of motion was 122.6 degree (range 105-135 degree) and the post-operative range 123.86 degree (range 90-135 degree). The average pre-operative lateral condylar prominence index (LCPI) was 175.56 (range 128-232) and the post-operative lateral condylar prominence 156 (range 100-240). Based on Bellmore criteria, 25 patients showed excellent, three good and two a poor result. Modified French technique of supracondylar osteotomy has excellent results in the management of cubitus varus in terms of cosmesis, radiological findings and fewer complications. (author)

  1. Solution of elliptic partial differential equations by fast Poisson solvers using a local relaxation factor. 2: Two-step method

    Science.gov (United States)

    Chang, S. C.

    1986-01-01

    A two-step semidirect procedure is developed to accelerate the one-step procedure described in NASA TP-2529. For a set of constant coefficient model problems, the acceleration factor increases from 1 to 2 as the one-step procedure convergence rate decreases from + infinity to 0. It is also shown numerically that the two-step procedure can substantially accelerate the convergence of the numerical solution of many partial differential equations (PDE's) with variable coefficients.

  2. Effective detection of toxigenic Clostridium difficile by a two-step algorithm including tests for antigen and cytotoxin.

    Science.gov (United States)

    Ticehurst, John R; Aird, Deborah Z; Dam, Lisa M; Borek, Anita P; Hargrove, John T; Carroll, Karen C

    2006-03-01

    We evaluated a two-step algorithm for detecting toxigenic Clostridium difficile: an enzyme immunoassay for glutamate dehydrogenase antigen (Ag-EIA) and then, for antigen-positive specimens, a concurrent cell culture cytotoxicity neutralization assay (CCNA). Antigen-negative results were > or = 99% predictive of CCNA negativity. Because the Ag-EIA reduced cell culture workload by approximately 75 to 80% and two-step testing was complete in CCNA alone had been performed on all 5,887 specimens.

  3. Triple osteotomy of the pelvis and trochanteric osteotomy as a treatment for hip dysplasia in the immature dog: the surgical technique and results of 77 consecutive operations

    International Nuclear Information System (INIS)

    Schrader, S.C.

    1986-01-01

    Triple osteotomy of the pelvis with transplantation of the greater trochanter was performed in 41 immature dogs (77 hips) with hip dysplasia. Before surgery, all hips were moderately to severely subluxated and unstable on palpation. The juxta-acetabular location of the ilial, ischial, and pubic osteotomies allowed repositioning of the acetabulum over the femoral head even when subluxation was severe. The acetabular fragment was rotated 70 degrees to 90 degrees in all hips. After surgery, craniodorsal coverage of the femoral head was increased and each hip was stable on palpation. Bilateral procedures were performed 4 to 7 weeks apart. The functional status of the limb was assessed and physical examination and radiography were performed in 71% (55) of the hips 1.0 to 5.5 years (mean, 2.7 years) after surgery. Functional ability was considered satisfactory in 93% (51) of the limbs, though few dogs had a normal gait. On palpation, all hips were stable and all but one were evaluated as nonpainful. In most instances, contact between the femoral neck and the repositioned acetabular rim resulted in a variable amount of crepitus and restriction of motion when the hip was abducted and rotated externally and internally. Eighty-two percent (45) of the hips had little or no evidence of degenerative joint disease. A satisfactory functional, physical, and radiographic result was obtained in 73% (40) of the hips

  4. Two-photon-like microscopy with orders-of-magnitude lower illumination intensity via two-step fluorescence.

    Science.gov (United States)

    Ingaramo, Maria; York, Andrew G; Andrade, Eric J; Rainey, Kristin; Patterson, George H

    2015-09-03

    We describe two-step fluorescence microscopy, a new approach to non-linear imaging based on positive reversible photoswitchable fluorescent probes. The protein Padron approximates ideal two-step fluorescent behaviour: it equilibrates to an inactive state, converts to an active state under blue light, and blue light also excites this active state to fluoresce. Both activation and excitation are linear processes, but the total fluorescent signal is quadratic, proportional to the square of the illumination dose. Here, we use Padron's quadratic non-linearity to demonstrate the principle of two-step microscopy, similar in principle to two-photon microscopy but with orders-of-magnitude better cross-section. As with two-photon, quadratic non-linearity from two-step fluorescence improves resolution and reduces unwanted out-of-focus excitation, and is compatible with structured illumination microscopy. We also show two-step and two-photon imaging can be combined to give quartic non-linearity, further improving imaging in challenging samples. With further improvements, two-step fluorophores could replace conventional fluorophores for many imaging applications.

  5. Analysis of instrumentation failures after three column osteotomies of the spine.

    Science.gov (United States)

    Kavadi, Niranjan; Tallarico, Richard A; Lavelle, William F

    2017-01-01

    Correction of fixed spinal imbalance in a sagittal and/or coronal plane frequently needs a tricolumnar wedge resection when the deformity is rigid. Complications associated with deformity correction surgery are pseudoarthrosis and implant failure located along the construct. The purposes of this study were to assess comparative rates of pseudoarthrosis (implant failure) at weaker points along lumbosacral junction and level of osteotomy, estimate overall incidence of implant failure, and comparatively analyze failures at different points along the construct. This was an IRB approved, single center study retrospective analysis. Twenty-six patients who underwent three column osteotomies were grouped according to procedure: pedicle subtraction osteotomy (PSO, ( n  = 18)); vertebral column resection (VCR, ( n  = 4)); hemivertebra excision (HE, ( n  = 2)); and extracavitary corpectomy (EC, ( n  = 2)). Follow-up data is presented on all of the study patients. Number of levels of fusion, anchors, percent saturation of fixation levels, type of bone graft and graft substitutes, and rod material and diameter were recorded. Radiographical data was reviewed preoperatively and postoperatively at 2 weeks and 3, 6, and 12 months and annually to determine sagittal and coronal balance, lumbopelvic parameters, presence or absence of interbody structural support, laterality or rod failure, and time to implant failure. Twenty-seven percent (7/26) patients demonstrated rod breakage either unilaterally ( N  = 2) or bilaterally ( N  = 5) during follow-up. Seventy-one percent had increasing back pain or worsening sagittal balance, while remaining failures found incidentally. No failures in children were seen. Tricolumnar osteotomy by posterior approach is a valuable tool. Rod failures found approximately 1 year from surgery, with 86% located at level of osteotomy and 14% at lumbosacral junction. Possible reasons are increased stress in the rod at this point and

  6. Physicochemical Properties of Jatropha Oil-Based Polyol Produced by a Two Steps Method.

    Science.gov (United States)

    Saalah, Sariah; Abdullah, Luqman Chuah; Aung, Min Min; Biak, Dayang Radiah Awang; Basri, Mahiran; Jusoh, Emiliana Rose; Mamat, Suhaini

    2017-03-29

    A low cost, abundant, and renewable vegetable oil source has been gaining increasing attention due to its potential to be chemically modified to polyol and thence to become an alternative replacement for the petroleum-based polyol in polyurethane production. In this study, jatropha oil-based polyol (JOL) was synthesised from non-edible jatropha oil by a two steps process, namely epoxidation and oxirane ring opening. In the first step, the effect of the reaction temperature, the molar ratio of the oil double bond to formic acid, and the reaction time on the oxirane oxygen content (OOC) of the epoxidised jatropha oil (EJO) were investigated. It was found that 4.3% OOC could be achieved with a molar ratio of 1:0.6, a reaction temperature of 60 °C, and 4 h of reaction. Consequently, a series of polyols with hydroxyl numbers in the range of 138-217 mgKOH/g were produced by oxirane ring opening of EJOs, and the physicochemical and rheological properties were studied. Both the EJOs and the JOLs are liquid and have a number average molecular weight ( M n ) in the range of 834 to 1457 g/mol and 1349 to 2129 g/mol, respectively. The JOLs exhibited Newtonian behaviour, with a low viscosity of 430-970 mPas. Finally, the JOL with a hydroxyl number of 161 mgKOH/g was further used to synthesise aqueous polyurethane dispersion, and the urethane formation was successfully monitored by Fourier Transform Infrared (FTIR).

  7. A two-step super-Gaussian independent component analysis approach for fMRI data.

    Science.gov (United States)

    Ge, Ruiyang; Yao, Li; Zhang, Hang; Long, Zhiying

    2015-09-01

    Independent component analysis (ICA) has been widely applied to functional magnetic resonance imaging (fMRI) data analysis. Although ICA assumes that the sources underlying data are statistically independent, it usually ignores sources' additional properties, such as sparsity. In this study, we propose a two-step super-GaussianICA (2SGICA) method that incorporates the sparse prior of the sources into the ICA model. 2SGICA uses the super-Gaussian ICA (SGICA) algorithm that is based on a simplified Lewicki-Sejnowski's model to obtain the initial source estimate in the first step. Using a kernel estimator technique, the source density is acquired and fitted to the Laplacian function based on the initial source estimates. The fitted Laplacian prior is used for each source at the second SGICA step. Moreover, the automatic target generation process for initial value generation is used in 2SGICA to guarantee the stability of the algorithm. An adaptive step size selection criterion is also implemented in the proposed algorithm. We performed experimental tests on both simulated data and real fMRI data to investigate the feasibility and robustness of 2SGICA and made a performance comparison between InfomaxICA, FastICA, mean field ICA (MFICA) with Laplacian prior, sparse online dictionary learning (ODL), SGICA and 2SGICA. Both simulated and real fMRI experiments showed that the 2SGICA was most robust to noises, and had the best spatial detection power and the time course estimation among the six methods. Copyright © 2015. Published by Elsevier Inc.

  8. A two-step strategy for neuronal differentiation in vitro of human dental follicle cells.

    Science.gov (United States)

    Völlner, Florian; Ernst, Wolfgang; Driemel, Oliver; Morsczeck, Christian

    2009-06-01

    Human dental follicle cells (DFCs) derived from wisdom teeth are precursor cells for cementoblasts. In this study, we recognized that naïve DFCs express constitutively the early neural cell marker beta-III-tubulin. Interestingly, DFCs formed beta-III-tubulin-positive neurosphere-like cell clusters (NLCCs) on low-attachment cell culture dishes in serum-replacement medium (SRM). For a detailed examination of the neural differentiation potential, DFCs were cultivated in different compositions of SRM containing supplements such as N2, B27, G5 and the neural stem cell supplement. Moreover, these cell culture media were combined with different cell culture substrates such as gelatin, laminin, poly-L-ornithine or poly-L-lysine. After cultivation in SRM, DFCs differentiated into cells with small cell bodies and long cellular extrusions. The expression of nestin, beta-III-tubulin, neuron-specific enolase (NSE) and neurofilament was up-regulated in SRM supplemented with G5, a cell culture supplement for glial cells, and the neural stem cell supplement. DFCs formed NLCCs and demonstrated an increased gene expression of neural cell markers beta-III-tubulin, NSE, nestin and for small neuron markers such as neuropeptides galanin (GAL) and tachykinin (TAC1) after cultivation on poly-L-lysine. For a further neural differentiation NLCC-derived cells were sub-cultivated on laminin and poly-L-ornithine cell culture substrate. After 2 weeks of differentiation, DFCs exposed neural-like cell morphology with small neurite-like cell extrusions. These cells differentially express neurofilament and NSE, but only low levels of beta-III-tubulin and nestin. In conclusion, we demonstrated the differentiation of human DFCs into neuron-like cells after a two-step strategy for neuronal differentiation.

  9. Porous plasmonic nanocomposites for SERS substrates fabricated by two-step laser method

    Energy Technology Data Exchange (ETDEWEB)

    Koleva, M.E., E-mail: mihaela_ek@yahoo.com [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee blvd., Sofia 1784 (Bulgaria); International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 (Japan); Nedyalkov, N.N.; Atanasov, P.A. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee blvd., Sofia 1784 (Bulgaria); Gerlach, J.W.; Hirsch, D.; Prager, A.; Rauschenbach, B. [Leibniz Institute of Surface Modification (IOM), Permoserstrasse 15, D-04318 Leipzig (Germany); Fukata, N.; Jevasuwan, W. [International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 (Japan)

    2016-04-25

    This research is focused on investigation of coupled plasmonic/metal-semiconductor nanomaterials. A two-step laser-assisted method is demonstrated for formation of plasmonic Ag nanoparticles (NPs) distributed into porous metal–oxide semiconductors. The mosaic Ag-ZnO target is used for laser ablation and, subsequently, laser annealing of the deposited layer is applied. The plasmon resonance properties of the nanostructures produced are confirmed by optical transmission spectroscopy. The wurtzite structure of ZnO is formed with tilted c-axis orientation and, respectively, a mixed Raman mode appears at 580 cm{sup −1}. The oxygen pressure applied during a deposition process has impact on the morphology and thickness of the porous nanostructures, but not on the size and size distribution of AgNPs. The porous nanocomposites exhibited potential for SERS applications, most pronounced for the oxygen deficient sample, grown at lower oxygen pressure. The observed considerable SERS enhancement of R6G molecules on AgNP/ZnO can be attributed to the ZnO-to-molecule charge transfer contribution, enhanced by the additional electrons from the local surface plasmon resonance (LSPR) of AgNPs to the ZnO through the conduction band. - Highlights: • Porous AgNPs/ZnO composites are obtained by laser deposition and laser annealing. • Morphology and properties depend on growth oxygen pressure. • The emergence of mixed-symmetry Raman mode at 580 cm{sup −1} is registered. • The AgNPs/ZnO porous nanocomposites are suitable for SERS-active substrates. • The charge transfer enhanced by LSPR has a contribution to SERS effect.

  10. Outcomes of Two-Step Revisional Bariatric Surgery: Reasons for the Gastric Banding Explantation Matter.

    Science.gov (United States)

    Barreto, Savio George; Chisholm, Jacob; Schloithe, Ann; Collins, Jane; Kow, Lilian

    2018-02-01

    The purpose of this study is to determine whether the reason for gastric band explantation would influence percentage excess weight loss (%EWL) following revisional Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). This is a retrospective cohort study, whose data are maintained in a prospective surgical database. The study period was from January 2012 to March 2017. Revisional surgeries were performed in a two-step manner, namely, first surgery LAGB explantation and second surgery (RYGB or SG). Two-way between-groups analysis of variance was used to examine effects of reason for band explantation (failed versus complication) and type of revisional surgery (RYGB versus SG) on %EWL at 10 months, 1 and 2 years. Cohort included 171 patients-146 women (85.4%) and 25 men, median age 51 years (range 22-76). Band-related complications accounted for 55% of explantations. Overall, 95 patients (56%) underwent a revisional RYGB, and 76 patients underwent a revisional SG. There was no difference in age or gender in terms of reason for band explantation or choice of revisional surgery. There was no difference in morbidity between the two groups (SG 2.6% versus RYGB 4.2%; p = .464). Patients undergoing revisional RYGB for failed weight loss had a significantly lower %EWL at 2 years compared to patients undergoing an SG for failed weight loss (p = .014) or an RYGB for band-related complications (p = .021). Patients undergoing revisional RYGB following band explantation for failed weight loss have a significantly lower %EWL at 2 years compared to patients undergoing an SG for failed weight loss or an RYGB for band-related complications.

  11. Two-step recrystallization of water in concentrated aqueous solution of poly(ethylene glycol).

    Science.gov (United States)

    Gemmei-Ide, Makoto; Motonaga, Tetsuya; Kasai, Ryosuke; Kitano, Hiromi

    2013-02-21

    Crystallization behavior of water in a concentrated aqueous solution of poly(ethylene glycol) (PEG) with a water content of 37.5 wt % was investigated by temperature variable mid-infrared (mid-IR) spectroscopy in a temperature range of 298-170 K. The mid-IR spectrum of water at 298 K showed that a large water cluster was not formed and that most of the water molecules were associated with the PEG chain. Ice formation, however, occurred as found in previous studies by differential scanning calorimetory. Ice formations were grouped into three types: crystallization at 231 K during cooling, that at 198 K during heating, and that at 210 K during heating. The latter two were just recrystallization. These ice formations were the direct transition from hydration species to ice without condensation regardless of crystallization or recrystallization. This means that the recrystallized water in the present system was not generated from low-density amorphous solid water. At a low cooling rate, nearly complete crystallization at 231 K during cooling and no recrystallization were observed. At a high cooling rate, no crystallization and two-step recrystallization at 198 and 210 K were observed. The former and latter recrystallizations were found to be generated from water associated with the PEG chains with ttg (the sequence -O-CH(2)-CH(2)-O- having a trans (t) conformation about the -C-O- bond and a gauche (g) conformation about the -C-C- bond) and random conformations, respectively. These results indicate that recrystallizable water does not have a single specific water structure.

  12. Physicochemical Properties of Jatropha Oil-Based Polyol Produced by a Two Steps Method

    Directory of Open Access Journals (Sweden)

    Sariah Saalah

    2017-03-01

    Full Text Available A low cost, abundant, and renewable vegetable oil source has been gaining increasing attention due to its potential to be chemically modified to polyol and thence to become an alternative replacement for the petroleum-based polyol in polyurethane production. In this study, jatropha oil-based polyol (JOL was synthesised from non-edible jatropha oil by a two steps process, namely epoxidation and oxirane ring opening. In the first step, the effect of the reaction temperature, the molar ratio of the oil double bond to formic acid, and the reaction time on the oxirane oxygen content (OOC of the epoxidised jatropha oil (EJO were investigated. It was found that 4.3% OOC could be achieved with a molar ratio of 1:0.6, a reaction temperature of 60 °C, and 4 h of reaction. Consequently, a series of polyols with hydroxyl numbers in the range of 138–217 mgKOH/g were produced by oxirane ring opening of EJOs, and the physicochemical and rheological properties were studied. Both the EJOs and the JOLs are liquid and have a number average molecular weight (Mn in the range of 834 to 1457 g/mol and 1349 to 2129 g/mol, respectively. The JOLs exhibited Newtonian behaviour, with a low viscosity of 430–970 mPas. Finally, the JOL with a hydroxyl number of 161 mgKOH/g was further used to synthesise aqueous polyurethane dispersion, and the urethane formation was successfully monitored by Fourier Transform Infrared (FTIR.

  13. A two-step method for fast and reliable EUV mask metrology

    Science.gov (United States)

    Helfenstein, Patrick; Mochi, Iacopo; Rajendran, Rajeev; Yoshitake, Shusuke; Ekinci, Yasin

    2017-03-01

    One of the major obstacles towards the implementation of extreme ultraviolet lithography for upcoming technology nodes in semiconductor industry remains the realization of a fast and reliable detection methods patterned mask defects. We are developing a reflective EUV mask-scanning lensless imaging tool (RESCAN), installed at the Swiss Light Source synchrotron at the Paul Scherrer Institut. Our system is based on a two-step defect inspection method. In the first step, a low-resolution defect map is generated by die to die comparison of the diffraction patterns from areas with programmed defects, to those from areas that are known to be defect-free on our test sample. In a later stage, a die to database comparison will be implemented in which the measured diffraction patterns will be compared to those calculated directly from the mask layout. This Scattering Scanning Contrast Microscopy technique operates purely in the Fourier domain without the need to obtain the aerial image and, given a sufficient signal to noise ratio, defects are found in a fast and reliable way, albeit with a location accuracy limited by the spot size of the incident illumination. Having thus identified rough locations for the defects, a fine scan is carried out in the vicinity of these locations. Since our source delivers coherent illumination, we can use an iterative phase-retrieval method to reconstruct the aerial image of the scanned area with - in principle - diffraction-limited resolution without the need of an objective lens. Here, we will focus on the aerial image reconstruction technique and give a few examples to illustrate the capability of the method.

  14. Development of adsorptive hybrid filters to enable two-step purification of biologics

    Science.gov (United States)

    Peck, Michael; Voloshin, Alexei M.; Moreno, Angela M.; Tan, Zhijun; Hester, Jonathan; Borys, Michael C.; Li, Zheng Jian

    2017-01-01

    ABSTRACT Recent progress in mammalian cell culture process has resulted in significantly increased product titers, but also a substantial increase in process- and product-related impurities. Due to the diverse physicochemical properties of these impurities, there is constant need for new technologies that offer higher productivity and improved economics without sacrificing the process robustness required to meet final drug substance specifications. Here, we examined the use of new synthetic adsorptive hybrid filters (AHF) modified with the high binding capacity of quaternary amine (Emphaze™ AEX) and salt-tolerant biomimetic (Emphaze™ ST-AEX) ligands for clearance of process-related impurities like host cell protein (HCP), residual DNA, and virus. The potential to remove soluble aggregates was also examined. Our aim was to develop a mechanistic understanding of the interactions governing adsorptive removal of impurities during filtration by evaluating the effect of various filter types, feed streams, and process conditions on impurity removal. The ionic capacity of these filters was measured and correlated with their ability to remove impurities for multiple molecules. The ionic capacity of AHF significantly exceeded that of traditional adsorptive depth filters (ADF) by 40% for the Emphaze™ AEX and by 700% for the Emphaze™ ST-AEX, providing substantially higher reduction of soluble anionic impurities, including DNA, HCPs and model virus. Nevertheless, we determined that ADF with filter aid provided additional hydrophobic functionality that resulted in removal of higher molecular weight species than AHF. Implementing AHF demonstrated improved process-related impurity removal and viral clearance after Protein A chromatography and enabled a two-step purification process. The consequences of enhanced process performance are far reaching because it allows the downstream polishing train to be restructured and simplified, and chromatographic purity standards to be

  15. Effect of two-step functionalization of Ti by chemical processes on protein adsorption

    Science.gov (United States)

    Pisarek, M.; Roguska, A.; Andrzejczuk, M.; Marcon, L.; Szunerits, S.; Lewandowska, M.; Janik-Czachor, M.

    2011-07-01

    Titanium and its alloys are widely used for orthopedic and dental implants because of their superior mechanical properties, low modulus, excellent corrosion resistance and good biocompatibility. However, it takes several months for titanium implants and bone tissue to reach integration. Hence, there is growing interest in shortening the process of osseointegration and thereby reducing surgical restrictions. Various surface modifications have been applied to form a bioactive titanium oxide layer on the metal surface, which is known to accelerate osseointegration. The present work shows that titanium dioxide (TiO 2) layers formed on titanium substrates by etching in a solution of sodium hydroxide (NaOH) or hydrogen peroxide/phosphoric acid (H 3PO 4/H 2O 2, with a volume ratio of 1:1) are highly suitable pre-treatments for apatite-like coating deposition. Using a two-step procedure (etching in an alkaline or acidic solution followed by soaking in Hanks' medium), biomimetic calcium phosphate coatings were deposited on porous TiO 2 layers. The combined effects of surface topography and chemistry on the formation of the calcium phosphate layer are presented. The topography of the TiO 2 layers was characterized using HR-SEM and AFM techniques. The nucleation and growth of calcium phosphate (Ca-P) coatings deposited on TiO 2 porous layers from Hanks' solution was investigated using HR-SEM microscopy. AES, XPS and FTIR surface analytical techniques were used to characterize the titanium dioxide layers before and after deposition of the calcium phosphate coatings, as well as after the process of protein adsorption. To evaluate the potential use of such materials for biomedical applications, the adsorption of serum albumin, the most abundant protein in the blood, was studied on such surfaces.

  16. An Umeclidinium membrane sensor; Two-step optimization strategy for improved responses.

    Science.gov (United States)

    Yehia, Ali M; Monir, Hany H

    2017-09-01

    In the scientific context of membrane sensors and improved experimentation, we devised an experimentally designed protocol for sensor optimization. Two-step strategy was implemented for Umeclidinium bromide (UMEC) analysis which is a novel quinuclidine-based muscarinic antagonist used for maintenance treatment of symptoms accompanied with chronic obstructive pulmonary disease. In the first place, membrane components were screened for ideal ion exchanger, ionophore and plasticizer using three categorical factors at three levels in Taguchi design. Secondly, experimentally designed optimization was followed in order to tune the sensor up for finest responses. Twelve experiments were randomly carried out in a continuous factor design. Nernstian response, detection limit and selectivity were assigned as responses in these designs. The optimized membrane sensor contained tetrakis-[3,5-bis(trifluoro- methyl)phenyl] borate (0.44wt%) and calix[6]arene (0.43wt%) in 50.00% PVC plasticized with 49.13wt% 2-ni-tro-phenyl octylether. This sensor, along with an optimum concentration of inner filling solution (2×10 -4 molL -1 UMEC) and 2h of soaking time, attained the design objectives. Nernstian response approached 59.7mV/decade and detection limit decreased by about two order of magnitude (8×10 -8 mol L -1 ) through this optimization protocol. The proposed sensor was validated for UMEC determination in its linear range (3.16×10 -7 -1×10 -3 mol L -1 ) and challenged for selective discrimination of other congeners and inorganic cations. Results of INCRUSE ELLIPTA ® inhalation powder analyses obtained from the proposed sensor and manufacturer's UPLC were statistically compared. Moreover the proposed sensor was successfully used for the determination of UMEC in plasma samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Improving powder flow properties of a direct compression formulation using a two-step glidant mixing process.

    Science.gov (United States)

    Abe, Hidaka; Yasui, Shinichiro; Kuwata, Aya; Takeuchi, Hirofumi

    2009-07-01

    To improve powder flow of a high-dose direct compression formulation (drug content 30%), we compared a two-step operation for mixing glidants with a conventional one-step glidant mixing process. This two-step mixing operation was studied with two kinds of mixtures; an active pharmaceutical ingredient (API)-glidant combination and a direct compression excipient-glidant combination. The two-step operation permitted the selection of the optimum glidant type and concentration in each glidant-mixing procedure even though the formulation had different powder properties such as micronized API and enlarged direct compression vehicles, whereas the conventional approaches forced the selection of a certain glidant type and concentration at one-step mixing. The addition of 0.5% nonporous silica markedly improved API flow. In contrast, 1.0% porous silica was the appropriate glidant to enhance excipient flow at direct compression excipient-glidant mixing. The two-step operation dominantly enhanced powder flow when the appropriate API-glidant mixture and the suitable direct compression excipients-glidant mixture were blended compared to the one-step operation with its optimum glidant concentration. The results showed that the angle of repose was 43 degrees and the critical orifice diameter was 10 mm in the two-step operation, whereas it was 47 degrees and 16 mm in the one-step operation. The two-step operation of glidant mixing enhanced powder flow of the high-dose direct compression formulation compared with the one-step operation. The two-step operation eliminates the bottleneck of powder flow and allows direct compression to be more worth applying for formulation and process development trials.

  18. Prostate ultrasound imaging: evaluation of a two-step scoring system in the diagnosis of prostate cancer.

    Science.gov (United States)

    Gao, Yong; Liao, Xin-Hong; Ma, Yan; Lu, Lu; Wei, Li-Yan; Yan, Xue

    2017-12-01

    This study aims to investigate the feasibility and performance of a two-step scoring system of ultrasound imaging in the diagnosis of prostate cancer. 75 patients with 888 consecutive histopathologically verified lesions were included in this study. Step 1, an initial 5-point scoring system was developed based on conventional transrectal ultrasound (TRUS). Step 2, a final scoring system was evaluated according to contrast-enhanced transrectal ultrasound (CE-TRUS). Each lesion was evaluated using the two-step scoring system (step 1 + step 2) and compared with only using conventional TRUS (step 1). 888 lesions were histologically verified: 315 of them were prostate cancer from 46 patients and 573 were benign prostatic hypertrophy (BPH) from 29 patients. According to the two-step scoring system, 284 lesions were upgraded and 130 lesions were downgraded from step 1 to step 2 (this means using step 2 to assess the results by step 1). However, 96 cases were improperly upgraded after step 2 and 48 malignant lesions were still missed after step 2 as score-1. For the two-step scoring system, the sensitivity, specificity, and accuracy were 84.7%, 83.2%, and 83.7%, respectively, versus 22.8%, 96.6%, and 70.4%, respectively, for conventional TRUS. The area under the ROC curve (AUC) for lesion diagnosis was 0.799-0.952 for the two-step scoring system, versus 0.479-0.712 for conventional TRUS. The difference in the diagnostic accuracy of the two-step scoring system and conventional TRUS was statistically significant (Pprostate cancer. The application of the two-step scoring system for prostate cancer is promising.

  19. A Novel Two-Step Technique for Retrieving Fractured Peripherally Inserted Central Catheter Segments Migrating into the Heart or the Pulmonary Artery

    Directory of Open Access Journals (Sweden)

    Juan Peng

    2016-01-01

    Full Text Available Objective. To report the experience of a percutaneous technique for retrieving fractured peripherally inserted central catheter (PICC segments migrating into the heart or the pulmonary artery. Method. From April 2013 to July 2015, we performed percutaneous retrieval of fractured PICC segments migrating into the heart or the pulmonary artery in five cancer patients who had undergone chemotherapy via PICC. The fractures were diagnosed with chest plain radiography. The patients included three cases of breast cancer, one case of rectal cancer, and one case of lower limb Ewing’s tumor. The fractures were retained in the vessels of the patients for 1 to 3 days. All the fractures were retrieved by using a novel two-step technique in the digital subtraction angiography (DSA suite. This two-step technique involves inserting a pigtail catheter to the heart or the pulmonary artery to grasp the fractured catheter fragment and bring it to the lower segment of the inferior vena cava, followed by grasping and removing the catheter fragment with a retrieval loop system of the vena cava filter retrieval set. Result. The fractured PICC segments were removed successfully in all five patients via unilateral (four patients or bilateral (one patient femoral vein access. No complications occurred during the interventional procedure. Conclusion. Percutaneous retrieval can be a safe, convenient, and minimally invasive method for the removal of fractured PICC segments. The technique reported in this paper will be applicable for the retrieval of fractured PICC segments and other catheter fragments migrating into the heart or the pulmonary artery.

  20. Two-step deoxygenation at the end of the Paleoproterozoic Lomagundi Event

    Science.gov (United States)

    Ossa Ossa, Frantz; Eickmann, Benjamin; Hofmann, Axel; Planavsky, Noah J.; Asael, Dan; Pambo, Florent; Bekker, Andrey

    2018-03-01

    shallow (above storm wave base) marine environments. The presence of a shallow-water redoxcline points to a generally low-oxygen atmosphere-ocean system. Further, the negative co-variation between δ34 S and δ13 C values in sediments of the Francevillian Group and other sedimentary successions of similar age worldwide suggests that the inferred two-step deoxygenation corresponding to the end of the LE reflects global rather than local events that likely occurred between ∼2.1 and 2.05 Ga ago.

  1. Facile electrochemical detection of botulinum neurotoxin type E using a two-step proteolytic cleavage.

    Science.gov (United States)

    Park, Seonhwa; Shin, Yu Mi; Song, Ji-Joon; Yang, Haesik

    2015-10-15

    Facile electrochemical methods for measuring protease concentration or protease activity are essential for point-of-care testing of toxic proteases. However, electrochemical detection of proteases, such as botulinum neurotoxin type E (BoNT/E), that cleave a peptide bond between two specific amino acid residues is challenging. This study reports a facile and sensitive electrochemical method for BoNT/E detection. The method is based on a two-step proteolytic cleavage using a target BoNT/E light chain (BoNT/E-LC) and an externally supplemented exopeptidase, L-leucine-aminopeptidase (LAP). BoNT/E-LC cleaves a peptide bond between arginine and isoleucine in IDTQNRQIDRI-4-amino-1-naphthol (oligopeptide-AN) to generate isoleucine-AN. Subsequently, LAP cleaves a bond between isoleucine and AN to liberate a free electroactive AN species. The liberated AN participates in electrochemical-chemical-chemical (ECC) redox cycling involving Ru(NH3)6(3+), AN, and a reducing agent, which allows a high signal amplification. Electrochemical detection is carried out without surface modification of indium-tin oxide electrodes. We show that dithiothreitol is beneficial for enhancing the enzymatic activity of BoNT/E-LC and also for achieving a fast ECC redox cycling. An incubation temperature of 37°C and the use of phosphate buffered saline (PBS) buffer resulted in optimal signal-to-background ratios for efficient BoNT/E detection. BoNT/E-LC could be detected at concentrations of approximately 2.0 pg/mL, 0.2, and 3 ng/mL after 4h, 2h, and 15 min incubation in PBS buffer, respectively, and approximately 0.3 ng/mL after 2-h incubation in bottled water. The method developed could be applied in fast, sensitive, and selective detection of any protease that cleaves a peptide bond between two specific amino acid residues. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. A Readout IC Using Two-Step Fastest Signal Identification for Compact Data Acquisition of PET Systems.

    Science.gov (United States)

    Jung, Sung-Jin; Hong, Seong-Kwan; Kwon, Oh-Kyong

    2016-10-20

    A readout integrated circuit (ROIC) using two-step fastest signal identification (FSI) is proposed to reduce the number of input channels of a data acquisition (DAQ) block with a high-channel reduction ratio. The two-step FSI enables the proposed ROIC to filter out useless input signals that arise from scattering and electrical noise without using complex and bulky circuits. In addition, an asynchronous fastest signal identifier and a self-trimmed comparator are proposed to identify the fastest signal without using a high-frequency clock and to reduce misidentification, respectively. The channel reduction ratio of the proposed ROIC is 16:1 and can be extended to 16 × N :1 using N ROICs. To verify the performance of the two-step FSI, the proposed ROIC was implemented into a gamma photon detector module using a Geiger-mode avalanche photodiode with a lutetium-yttrium oxyorthosilicate array. The measured minimum detectable time is 1 ns. The difference of the measured energy and timing resolution between with and without the two-step FSI are 0.8% and 0.2 ns, respectively, which are negligibly small. These measurement results show that the proposed ROIC using the two-step FSI reduces the number of input channels of the DAQ block without sacrificing the performance of the positron emission tomography (PET) systems.

  3. Theoretical investigation on the performance of DNA electrophoresis under programmed step electric field strength: Two-step condition.

    Science.gov (United States)

    Ni, Yi; Liu, Chenchen; Chen, Qinmiao; Zhu, Xifang; Dou, Xiaoming

    2015-10-01

    Programmed step electric field strength is a simple-to-use technique that has already been reported to be effective to enhance the efficiency or speed of DNA electrophoresis. However, a global understanding and the details of this technique are still vague. In this paper, we investigated the influence of programmed step electric field strength by theoretical calculation and concentrated on a basic format named as two-step electric field strength. Both subtypes of two-step electric field strength conditions were considered. The important parameters, such as peak spacing, peak width, resolution, and migration time, were calculated in theory to understand the performance of DNA electrophoresis under programmed step electric field strength. The influence of two-step electric field strength on DNA electrophoresis was clearly revealed on a diagram of resolution versus migration time. Both resolution and speed of DNA electrophoresis under two-step electric field strength conditions are simply expressed by the shape of curves in the diagram. The possible shapes of curve were explored by calculation and shown in this paper. The subtype II of two-step electric field strength brings drastic variation on the resolution. Its limitations of enhancement and deterioration of resolution were predicted in theory. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. A two-step database search method improves sensitivity in peptide sequence matches for metaproteomics and proteogenomics studies.

    Science.gov (United States)

    Jagtap, Pratik; Goslinga, Jill; Kooren, Joel A; McGowan, Thomas; Wroblewski, Matthew S; Seymour, Sean L; Griffin, Timothy J

    2013-04-01

    Large databases (>10(6) sequences) used in metaproteomic and proteogenomic studies present challenges in matching peptide sequences to MS/MS data using database-search programs. Most notably, strict filtering to avoid false-positive matches leads to more false negatives, thus constraining the number of peptide matches. To address this challenge, we developed a two-step method wherein matches derived from a primary search against a large database were used to create a smaller subset database. The second search was performed against a target-decoy version of this subset database merged with a host database. High confidence peptide sequence matches were then used to infer protein identities. Applying our two-step method for both metaproteomic and proteogenomic analysis resulted in twice the number of high confidence peptide sequence matches in each case, as compared to the conventional one-step method. The two-step method captured almost all of the same peptides matched by the one-step method, with a majority of the additional matches being false negatives from the one-step method. Furthermore, the two-step method improved results regardless of the database search program used. Our results show that our two-step method maximizes the peptide matching sensitivity for applications requiring large databases, especially valuable for proteogenomics and metaproteomics studies. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Z-osteotomy in hallux valgus: clinical and radiological outcome after Scarf osteotomy

    Directory of Open Access Journals (Sweden)

    Marcus Jaeger

    2009-05-01

    Full Text Available Correction osteotomies of the first metatarsal are common surgical approaches in treating hallux valgus deformities whereas the Scarf osteotomy has gained popularity. The purpose of this study was to analyze short- and mid-term results in hallux valgus patients who underwent a Scarf osteotomy. The subjective and radiological outcome of 131 Scarf osteotomies (106 hallux valgus patients, mean age: 57.5 years, range: 22-90 years were retrospectively analyzed. Mean follow-up was 22.4 months (range: 6 months-5 years. Surgical indications were: intermetatarsal angle (IMA of 12-23°; increased proximal articular angle (PAA>8°, and range of motion of the metatarsophalangeal joint in flexion and extension >40°. Exclusion criteria were severe osteoporosis and/or osteoarthritis. The mean subjective range of motion (ROM of the great toe post-surgery was 0.8±1.73 points (0: full ROM, 10: total stiffness. The mean subjective cosmetic result was 2.7±2.7 points (0: excellent, 10: poor. The overall post-operative patient satisfaction with the result was high (2.1±2.5 points (0: excellent, 10: poor. The mean hallux valgus angle improvement was 16.6° (pre-operative mean value: 37.5° which was statistically significant (p<0.01. The IMA improved by an average of 5.96° from a pre-operative mean value of 15.4° (p<0.01. Neither osteonecrosis of the distal fragment nor peri-operative fractures were noted during the follow-up. In keeping with our follow-up results, the Scarf osteotomy approach shows potential in the therapy of hallux valgus. 筻

  6. Planetary In Situ Sample Analysis with Tandem Two-Step Laser Mass Spectrometry

    Science.gov (United States)

    Brinckerhoff, W. B.; Getty, S. A.; Cornish, T. J.; Ecelberger, S. A.; Li, X.; Merrill Floyd, M. A.; Arevalo, R.; Elsila, J.; Callahan, M. P.

    2012-12-01

    -) and organic moieties. Second, by focusing a separate "post-ionization" laser pulse just above the sample surface, we can achieve two-step laser mass spectrometry, or L2MS, in the same highly-miniaturized TOF-MS. L2MS enables selective analysis of aromatic organics even in the presence of a complex mineral matrix. Finally, by introducing an ion optical gate in the flight path, we are able to take advantage of the broad focusing capabilities of the "curved field" reflectron at the core of the TOF-MS to achieve pseudo-tandem structural analysis of selected organics. The high-speed gate is used to admit only the molecular ion/s of interest into the reflectron. Diagnostic fragments of the ion/s obtained through metastable decay or active collision-induced dissociation (CID) remain in focus despite having widely variable velocities and masses. As such even molecular isomers with differing fragmentation pathways may be distinguished through a series of pseudo-tandem mass spectra that could be obtained in an automatic process during a mission. The "real-world" benefits of these enhancements are being fully characterized using a set of synthetic and natural standard samples as well as several planetary analogs and meteorites.

  7. One step versus two step approach for gestational diabetes screening: systematic review and meta-analysis of the randomized trials.

    Science.gov (United States)

    Saccone, Gabriele; Caissutti, Claudia; Khalifeh, Adeeb; Meltzer, Sara; Scifres, Christina; Simhan, Hyagriv N; Kelekci, Sefa; Sevket, Osman; Berghella, Vincenzo

    2017-12-03

    To compare both the prevalence of gestational diabetes mellitus (GDM) as well as maternal and neonatal outcomes by either the one-step or the two-step approaches. Electronic databases were searched from their inception until June 2017. We included all randomized controlled trials (RCTs) comparing the one-step with the two-step approaches for the screening and diagnosis of GDM. The primary outcome was the incidence of GDM. Three RCTs (n = 2333 participants) were included in the meta-analysis. 910 were randomized to the one step approach (75 g, 2 hrs), and 1423 to the two step approach. No significant difference in the incidence of GDM was found comparing the one step versus the two step approaches (8.4 versus 4.3%; relative risk (RR) 1.64, 95%CI 0.77-3.48). Women screened with the one step approach had a significantly lower risk of preterm birth (PTB) (3.7 versus 7.6%; RR 0.49, 95%CI 0.27-0.88), cesarean delivery (16.3 versus 22.0%; RR 0.74, 95%CI 0.56-0.99), macrosomia (2.9 versus 6.9%; RR 0.43, 95%CI 0.22-0.82), neonatal hypoglycemia (1.7 versus 4.5%; RR 0.38, 95%CI 0.16-0.90), and admission to neonatal intensive care unit (NICU) (4.4 versus 9.0%; RR 0.49, 95%CI 0.29-0.84), compared to those randomized to screening with the two step approach. The one and the two step approaches were not associated with a significant difference in the incidence of GDM. However, the one step approach was associated with better maternal and perinatal outcomes.

  8. A region-based two-step P300-based brain-computer interface for patients with amyotrophic lateral sclerosis.

    Science.gov (United States)

    Ikegami, Shiro; Takano, Kouji; Kondo, Kiyohiko; Saeki, Naokatsu; Kansaku, Kenji

    2014-11-01

    The P300-based brain-computer interface (BCI) is designed to help patients with motor disabilities to control their environment, and it has been used successfully in patients with amyotrophic lateral sclerosis (ALS). However, some ALS patients were unable to use the visual P300-BCI with the conventional row/column presentation. In this study, we evaluated the effect of a newly developed region-based two-step P300 speller, which has a larger flashing area than the conventional visual array. Seven ALS patients and seven age- and sex-matched able-bodied control subjects were required to input hiragana characters using our P300 BCI system. We prepared two types of input procedures, the conventional row/column (RC) speller and the two-step speller, and evaluated their online performance. The mean online accuracy of the ALS patients was 24% for the RC condition and 55% for the two-step condition. The accuracy of the control subjects was 71% and 83% for the RC and two-step condition, respectively. Accuracy in ALS patients was significantly lower than that in the control subjects, and the new visual stimuli significantly increased accuracy of ALS patients. Using the new speller, two ALS patients showed an initial accuracy sufficient for practical use (>70%). The other two ALS patients, who performed better in the first trial using the new speller, continued to experience the BCI system, and their mean accuracy increased to 92%. The two-step procedure for the visual P300 BCI system provided significantly increased accuracy for ALS patients compared with a conventional RC speller. The new region-based two-step P300 speller was effective in ALS patients, and the system may be beneficial to expand their range of activities. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  9. Mitchell′s osteotomy in the management of hallux valgus: An Indian perspective

    Directory of Open Access Journals (Sweden)

    Baba Asif

    2009-01-01

    Full Text Available Background: Hallux valgus is a common condition that affects the forefoot. A large number of procedures are described for managing this condition. Mitchell′s osteotomy and its modifications are being widely used for treating hallux valgus. However, most of the studies describe the results from the developed world. We present results of the classic Mitchell′s osteotomy in hallux valgus in Indian subcontinent. Materials and Methods: Forty eight adult patients (including 12 bilateral ones in the age range of 18-60 years with hallux valgus were managed with the classic Mitchell′s osteotomy. Pain over the bunion was the reason for surgery in 53 of 60 feet and cosmesis in the remaining 7 feet. Patients with hallux valgus angle more than 20° degrees and not responding to a trial of conservative treatment were included. Patients having metatarsophalangeal (MTP joint osteoarthritis (Grade II and higher, hallux rigidus, rheumatoid arthritis, and with subluxation of MTP joint were excluded from the study. Further, patients with first metatarsal more than 3 mm shorter than second metatarsal were also excluded. Results: The average follow-up period is 3 yrs (range 18months - 6yrs. About 55 feet (83% were painless after surgery. Forty-two (70% patients were happy with the cosmetic results of the surgery. Metatarsalgia was the reason for dissatisfaction with the procedure in five patients. The average correction of hallux valgus and the intermetatarsal angles achieved was 19.7° and 6.9°, respectively. Using the Broughton and Winson scoring system, 37 (61.7% feet had excellent results, 18 (30% had good, and five (8.3% feet had a poor results. Conclusion: The classic Mitchell′s procedure is a simple procedure and gives good cosmetic and radiological results.

  10. Ulnar shortening osteotomy for distal radius malunion.

    Science.gov (United States)

    Kamal, Robin N; Leversedge, Fraser J

    2014-08-01

    Background Malunion is a common complication of distal radius fractures. Ulnar shortening osteotomy (USO) may be an effective treatment for distal radius malunion when appropriate indications are observed. Methods The use of USO for treatment of distal radius fracture malunion is described for older patients (typically patients >50 years) with dorsal or volar tilt less than 20 degrees and no carpal malalignment or intercarpal or distal radioulnar joint (DRUJ) arthritis. Description of Technique Preoperative radiographs are examined to ensure there are no contraindications to ulnar shortening osteotomy. The neutral posteroanterior (PA) radiograph is used to measure ulnar variance and to estimate the amount of ulnar shortening required. An ulnar, mid-sagittal incision is used and the dorsal sensory branch of the ulnar nerve is preserved. An USO-specific plating system with cutting jig is used to create parallel oblique osteotomies to facilitate shortening. Intraoperative fluoroscopy and clinical range of motion are checked to ensure adequate shortening and congruous reduction of the ulnar head within the sigmoid notch. Results Previous outcomes evaluation of USO has demonstrated improvement in functional activities, including average flexion-extension and pronosupination motions, and patient reported outcomes. Conclusion The concept and technique of USO are reviewed for the treatment of distal radius malunion when specific indications are observed. Careful attention to detail related to surgical indications and to surgical technique typically will improve range of motion, pain scores, and patient-reported outcomes and will reduce the inherent risks of the procedure, such as ulnar nonunion or the symptoms related to unrecognized joint arthritis.  Level IV.

  11. Comparative analysis of single-step and two-step biodiesel production using supercritical methanol on laboratory-scale

    International Nuclear Information System (INIS)

    Micic, Radoslav D.; Tomić, Milan D.; Kiss, Ferenc E.; Martinovic, Ferenc L.; Simikić, Mirko Ð.; Molnar, Tibor T.

    2016-01-01

    Highlights: • Single-step supercritical transesterification compared to the two-step process. • Two-step process: oil hydrolysis and subsequent supercritical methyl esterification. • Experiments were conducted in a laboratory-scale batch reactor. • Higher biodiesel yields in two-step process at milder reaction conditions. • Two-step process has potential to be cost-competitive with the single-step process. - Abstract: Single-step supercritical transesterification and two-step biodiesel production process consisting of oil hydrolysis and subsequent supercritical methyl esterification were studied and compared. For this purpose, comparative experiments were conducted in a laboratory-scale batch reactor and optimal reaction conditions (temperature, pressure, molar ratio and time) were determined. Results indicate that in comparison to a single-step transesterification, methyl esterification (second step of the two-step process) produces higher biodiesel yields (95 wt% vs. 91 wt%) at lower temperatures (270 °C vs. 350 °C), pressures (8 MPa vs. 12 MPa) and methanol to oil molar ratios (1:20 vs. 1:42). This can be explained by the fact that the reaction system consisting of free fatty acid (FFA) and methanol achieves supercritical condition at milder reaction conditions. Furthermore, the dissolved FFA increases the acidity of supercritical methanol and acts as an acid catalyst that increases the reaction rate. There is a direct correlation between FFA content of the product obtained in hydrolysis and biodiesel yields in methyl esterification. Therefore, the reaction parameters of hydrolysis were optimized to yield the highest FFA content at 12 MPa, 250 °C and 1:20 oil to water molar ratio. Results of direct material and energy costs comparison suggest that the process based on the two-step reaction has the potential to be cost-competitive with the process based on single-step supercritical transesterification. Higher biodiesel yields, similar or lower energy

  12. COMPARISON OF Sr ISOTOPIC RATIOS FROM TWO SOILS NEAR RAVENNA (ITALY USING AQUA REGIA AND TWO-STEP SEQUENTIAL EXTRACTS

    Directory of Open Access Journals (Sweden)

    Francesca Castorina

    2010-08-01

    Full Text Available The Sr-isotope ratios of several samples from a natural and an agricultural soil from Ravenna were determined using aqua regia and the two-step sequential extraction. Results indicate that the two-step extraction can provide the researcher with wider and more precise information on Sr sources, thus being a more suitable methodology for achieving scientific goals than the aqua regia extraction. Lastly, the extracts of hydrochloric acid and aqua regia display similar ranges of δ87Sr, indicating that the two procedures provide comparable information on Sr sources.

  13. Effective Detection of Toxigenic Clostridium difficile by a Two-Step Algorithm Including Tests for Antigen and Cytotoxin

    OpenAIRE

    Ticehurst, John R.; Aird, Deborah Z.; Dam, Lisa M.; Borek, Anita P.; Hargrove, John T.; Carroll, Karen C.

    2006-01-01

    We evaluated a two-step algorithm for detecting toxigenic Clostridium difficile: an enzyme immunoassay for glutamate dehydrogenase antigen (Ag-EIA) and then, for antigen-positive specimens, a concurrent cell culture cytotoxicity neutralization assay (CCNA). Antigen-negative results were ≥99% predictive of CCNA negativity. Because the Ag-EIA reduced cell culture workload by ≈75 to 80% and two-step testing was complete in ≤3 days, we decided that this algorithm would be effective. Over 6 months...

  14. Patella height changes post high tibial osteotomy

    Directory of Open Access Journals (Sweden)

    Siew Ghim Gooi

    2017-01-01

    Full Text Available Background: Medial opening wedge high tibial osteotomy (HTO is a well-described treatment in early medial compartmental osteoarthritis of the knee. However, two undesirable sequelae may follow –patella baja and changes in the posterior tibial slope (TS. Materials and Methods: We conducted a retrospective study in patients who underwent HTO in our center between September 2009 and February 2017. Preoperative and 6-week postoperative long-leg weight bearing films and lateral knee radiographs were assessed. Pre- and postoperative radiological measurements include the Caton-Deschamps Index (CDI, the mechanical axis deviation (MAD, and the posterior TS. Independant t-test and Pearson correlation test were performed. Results: A total of 106 knees were recruited. The mean age was 48.8 ± 10.8 years. 66 (62.3% and 40 (37.7% knees were from males and females, respectively. The mean pre- and postoperative measurements was (−9.70° ± 3.67° to 0.08° ± 2.80° (−varus; +valgus for the MAD, (7.14° ± 1.78° to 8.72° ± 3.11° for posterior TS, and (0.93° ± 0.084° to 0.82° ± 0.13° for CDI (P ≤ 0.001 for all. The association between patella height change and the level of osteotomy (supra-tubercle vs. infra-tubercle was statistically significant (P < 0.001. A supra-tubercle osteotomy cut significantly lowering patella height (P = 0.011. There was otherwise no statistically significant correlations between patella height changes and the correction angle (P = 0.187 or posterior TS change (P = 0.744. Conclusions: A medial opening wedge HTO above the tibial tubercle was significantly associated with lowering patella height or reducing CDI postoperatively. Based on our results, we would recommend the use of an infra-tubercle osteotomy during the corrective surgery to prevent the complication of patella baja.

  15. Posterior column reconstruction improves fusion rates at the level of osteotomy in three-column posterior-based osteotomies.

    Science.gov (United States)

    Lewis, Stephen J; Mohanty, Chandan; Gazendam, Aaron M; Kato, So; Keshen, Sam G; Lewis, Noah D; Magana, Sofia P; Perlmutter, David; Cape, Jennifer

    2018-03-01

    To determine the incidence of pseudarthrosis at the osteotomy site after three-column spinal osteotomies (3-COs) with posterior column reconstruction. 82 consecutive adult 3-COs (66 patients) with a minimum of 2-year follow-up were retrospectively reviewed. All cases underwent posterior 3-COs with two-rod constructs. The inferior facets of the proximal level were reduced to the superior facets of the distal level. If that was not possible, a structural piece of bone graft either from the local resection or a local rib was slotted in the posterior column defect to re-establish continual structural posterior bone across the lateral margins of the resection. No interbody cages were used at the level of the osteotomy. There were 34 thoracic osteotomies, 47 lumbar osteotomies and one sacral osteotomy with a mean follow-up of 52 (24-126) months. All cases underwent posterior column reconstructions described above and the addition of interbody support or additional posterior rods was not performed for fusion at the osteotomy level. Among them, 29 patients underwent one or more revision surgeries. There were three definite cases of pseudarthrosis at the osteotomy site (4%). Six revisions were also performed for pseudarthrosis at other levels. Restoration of the structural integrity of the posterior column in three-column posterior-based osteotomies was associated with > 95% fusion rate at the level of the osteotomy. Pseudarthrosis at other levels was the second most common reason for revision following adjacent segment disease in the long-term follow-up.

  16. Clinical evaluation of a biomechanical guidance system for periacetabular osteotomy.

    Science.gov (United States)

    Murphy, Ryan J; Armiger, Robert S; Lepistö, Jyri; Armand, Mehran

    2016-03-30

    Populations suffering from developmental dysplasia of the hip typically have reduced femoral coverage and experience joint pain while walking. Periacetabular osteotomy (PAO) is one surgical solution that realigns the acetabular fragment. This challenging surgery has a steep learning curve. Existing navigation systems for computer-assisted PAO neither track the released fragment nor offer the means to assess fragment location. An intraoperative workstation--the biomechanical guidance system (BGS)--developed for PAO incorporates intraoperative fragment tracking and acetabular characterization through radiographic angles and joint biomechanics. In this paper, we investigate the accuracy and effectiveness of the BGS for bone fragment tracking and acetabular characterization in clinical settings as compared to conventional techniques and postoperative assessments. We also report the issues encountered and our remedies when using the BGS in the clinical setting. Eleven consecutive patients (aged 22-48, mean 34, years) underwent 12 PAO surgeries (one bilateral surgery) where the BGS collected information on acetabular positioning. These measurements were compared with postoperative CT data and manual measurements made intraoperatively. No complications were reported during surgery, with surgical time-95-210 (mean 175) minutes-comparable to reported data for the conventional approach. The BGS-measured acetabular positioning showed strong agreement with postoperative CT measurements (-0.3-9.2, mean 3.7, degrees), whereas larger differences occurred between the surgeon's intraoperative manual measurements and postoperative CT measurements (-2.8-21.3, mean 10.5, degrees). The BGS successfully tracked the acetabular fragment in a clinical environment without introducing complications to the surgical workflow. Accurate 3D positioning of the acetabulum may provide more information intraoperatively (e.g., anatomical angles and biomechanics) without adversely impacting the surgery

  17. [A biomechanic study on the relapse after sagittal split and oblique osteotomy of Ramus].

    Science.gov (United States)

    Li, Wei; Song, Yufeng; Wang, Dazhang

    2004-02-01

    The relapse after orthognathic surgery was frequently reported in recent years. But up to now researches concerning bio-mechanic mechanism of relapse are rare. The purpose of this study, by imitating the operation on monkeys, was to examine the biomechanical properties and histological characteristics after operation in order to investigate the mechanism of the relapse after orthognathic surgery. 20 rhesus monkeys divided into two groups were subjected to bilateral sagittal split and oblique osteotomy, respectively. The broken strength, stress and strain of the operated sites were examined with the use of biomechanical methods, and the healing scab was observed using histological method and SEM at 3, 6, 12, 24 weeks after operation. The results obtained demonstrated that bone healing and biomechanical properties reached certain level after 6 to 12 weeks' recovery in both operation groups; the biomechanical properties and histological characteristics recovered faster in sagittal split group than in oblique osteotomy group. Histological examination also demonstrated similar results. From the data above it is suggested that the higher relapse rate in sagittal split may more closely related to the mechanical effect different from the scab healing, although 8 weeks' fixation may meet the requirement of clinical treatment, accessory fixation method should be adopted after the removal of inter-maxilla fixation.

  18. Bilateral ekstrauterin graviditet

    DEFF Research Database (Denmark)

    Kirkegaard, Ida; Kruse, Christina

    2009-01-01

    Bilateral tubal pregnancies are extremely rare and they are usually found after assisted reproductive techniques have been applied. A rare case of bilateral tubal pregnancy after natural conception, occurring in a woman without any predisposing factors for ectopic pregnancy, is presented....... The condition was diagnosed during laparoscopic surgery, and she was optimally treated with conservative tubal surgery. A short review of the literature is provided and discussed along with the clinical features, diagnostic difficulties and treatment options of bilateral tubal pregnancy. Udgivelsesdato: 2009...

  19. Six first metatarsal shaft osteotomies: mechanical and immobilization comparisons.

    Science.gov (United States)

    Trnka, H J; Parks, B G; Ivanic, G; Chu, I T; Easley, M E; Schon, L C; Myerson, M S

    2000-12-01

    Because malunion (usually with dorsal elevation of the first metatarsal) has been reported after the treatment of severe hallux valgus deformities by proximal osteotomies, the current study was designed to compare the sagittal stability of six different metatarsal shaft osteotomies: the proximal crescentic, proximal chevron, Mau, Scarf, Ludloff, and biplanar closing wedge osteotomies. A plate was used in the biplanar closing wedge osteotomy; all others used screws for fixation. Ten fresh-frozen, human anatomic lower extremity specimens were used for each osteotomy. Failure loads were measured as units of force (newtons) and converted to pressure (kilopascals). Then the F-Scan system, which uses a thin insole to measure plantar pressure, was used to evaluate the pressure under the first metatarsal of seven volunteers using four types of shoes. According to the results, in patients with normal bone stock who are compliant, any of the four shoe types tested may be used after a Ludloff, Scarf, biplanar wedge (plantar screw fixation), or Mau osteotomy, but the wedge-based shoe should be used after a proximal crescentic or chevron osteotomy or for patients with severe osteopenic bone.

  20. A comparison of piezosurgery with conventional techniques for internal osteotomy.

    Science.gov (United States)

    Koçak, I; Doğan, R; Gökler, O

    2017-06-01

    To compare conventional osteotomy with the piezosurgery medical device, in terms of postoperative edema, ecchymosis, pain, operation time, and mucosal integrity, in rhinoplasty patients. In this prospective study, 49 rhinoplasty patients were randomly divided into two groups according to osteotomy technique used, either conventional osteotomy or piezosurgery. For all patients, the total duration of the operation was recorded, and photographs were taken and scored for ecchymosis and edema on postoperative days 2, 4, and 7. In addition, pain level was evaluated on postoperative day 2, and mucosal integrity was assessed on day 4. All scoring and evaluation was conducted by a physician who was blinded to the osteotomy procedure. In the piezosurgery group, edema scores on postoperative day 2 and ecchymosis scores on postoperative days 2, 4, and 7 were significantly lower than in the conventional osteotomy group (p  0.05). Piezosurgery is a safe osteotomy method, with less edema (in the early postoperative period) and ecchymosis compared with conventional osteotomy, as well as less pain, a similar operation duration, and no mucosal damage.

  1. Velocity-space observation regions of high-resolution two-step reaction gamma-ray spectroscopy

    DEFF Research Database (Denmark)

    Salewski, Mirko; Nocente, M.; Gorini, G.

    2015-01-01

    High-resolution γ-ray spectroscopy (GRS) measurements resolve spectral shapes of Dopplerbroadened γ-rays. We calculate weight functions describing velocity-space sensitivities of any two-step reaction GRS measurements in magnetized plasmas using the resonant nuclear reaction 9Be(α, nγ)12C...

  2. Dietary assessment in the elderly: Application of a two-step semiquantitative food frequency questionnaire for epidemiological studies

    NARCIS (Netherlands)

    Klipstein-Grobusch, K.; Witteman, J.C.M.; Breeijen, J.H. den; Goldbohm, R.A.; Hofman, A.; Jong, P.T.V.M. de; Pols, H.A.; Grobbee, D.E.

    1999-01-01

    Objective: Description and application of an adapted semiquantitative food frequency questionnaire (SFFQ) for dietary assessment in the elderly population of the Rotterdam Study. Design: Dietary assessment consisting of a two-step approach was performed in 5434 participants (2225 men, 3029 women) of

  3. Analysis of Approximations and Aperture Distortion for 3D Migration of Bistatic Radar Data with the Two-Step Approach

    Directory of Open Access Journals (Sweden)

    Zanzi Luigi

    2010-01-01

    Full Text Available The two-step approach is a fast algorithm for 3D migration originally introduced to process zero-offset seismic data. Its application to monostatic GPR (Ground Penetrating Radar data is straightforward. A direct extension of the algorithm for the application to bistatic radar data is possible provided that the TX-RX azimuth is constant. As for the zero-offset case, the two-step operator is exactly equivalent to the one-step 3D operator for a constant velocity medium and is an approximation of the one-step 3D operator for a medium where the velocity varies vertically. Two methods are explored for handling a heterogeneous medium; both are suitable for the application of the two-step approach, and they are compared in terms of accuracy of the final 3D operator. The aperture of the two-step operator is discussed, and a solution is proposed to optimize its shape. The analysis is of interest for any NDT application where the medium is expected to be heterogeneous, or where the antenna is not in direct contact with the medium (e.g., NDT of artworks, humanitarian demining, radar with air-launched antennas.

  4. A two-step process of nitrous oxide before carbon dioxide for humanely euthanizing piglets: on-farm trials

    Science.gov (United States)

    The current methods of euthanizing neonatal piglets are raising concerns from the public and scientists. Our experiment tests the use of a two-step euthanasia method using nitrous oxide (N2O) for six minutes and then carbon dioxide (CO2) as a more humane way to euthanize piglets compared to just usi...

  5. Two-step laser ionization schemes for in-gas laser ionization and spectroscopy of radioactive isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Kudryavtsev, Yu., E-mail: yuri.kudryavtsev@fys.kuleuven.be; Ferrer, R.; Huyse, M.; Van den Bergh, P.; Van Duppen, P. [Instituut voor Kern- en Stralingsfysica, KU Leuven, 3001 Leuven (Belgium); Vermeeren, L. [SCK-CEN, Nuclear Research Centre, Boeretang 200, B-2400 Mol (Belgium)

    2014-02-15

    The in-gas laser ionization and spectroscopy technique has been developed at the Leuven isotope separator on-line facility for the production and in-source laser spectroscopy studies of short-lived radioactive isotopes. In this article, results from a study to identify efficient optical schemes for the two-step resonance laser ionization of 18 elements are presented.

  6. Two-step laser ionization schemes for in-gas laser ionization and spectroscopy of radioactive isotopes.

    Science.gov (United States)

    Kudryavtsev, Yu; Ferrer, R; Huyse, M; Van den Bergh, P; Van Duppen, P; Vermeeren, L

    2014-02-01

    The in-gas laser ionization and spectroscopy technique has been developed at the Leuven isotope separator on-line facility for the production and in-source laser spectroscopy studies of short-lived radioactive isotopes. In this article, results from a study to identify efficient optical schemes for the two-step resonance laser ionization of 18 elements are presented.

  7. Theory of Square-Wave Voltammetry of Two-Step Electrode Reaction Using an Inverse Scan Direction

    OpenAIRE

    Lovrić, Milivoj; Komorsky-Lovrić, Šebojka

    2011-01-01

    A theory of square-wave voltammetry of two-step electrode reaction with kinetically controlled electron transfers is developed, and a special case of thermodynamically unstable intermediate is analyzed. If the first reaction step is reversible and the second one is quasireversible, the response splits into two peaks if the scan direction is inverted. The separation of these peaks increases with frequency.

  8. One-step (standard) versus two-step surgical approach in adolescent idiopathic scoliosis posterior spinal fusion: Which is better?

    Science.gov (United States)

    Ramirez, Norman; Valentin, Pablo; García-Cartagena, Manuel; Samalot, Solais; Iriarte, Ivan

    2016-07-01

    A retrospective cohort study with IRB approval. Significant blood loss remains an important concern in terms of the performance of the posterior spinal fusion in adolescent idiopathic scoliosis. Several strategies have been reported to minimize blood loss during surgery. In order to address the need to minimize blood loss without sacrificing the quality of the fusion, in our hospital, we adopted a two-step surgical approach. This surgical approach consist of the exposure and instrumentation of the lumbar region prior to and followed by an extension of the surgical incision to the thoracic region for its subsequent instrumentation. The main purpose of this study was to compare a two-step surgical approach with the one-step (standard) approach. This study was a review of all the data on consecutive posterior spinal fusion surgeries performed by a specific two-surgeon team during 2004-2013. Demographics, surgical variables, radiographic findings, and outcomes regarding blood loss, morbidity, and the duration of the procedure were evaluated. Eighty-five patients underwent the standard surgical exposure, and 41 patients underwent the two-step surgical technique. With the exception of BMI, neither group showed any statistically preoperative variable significant differences. None of the postoperative outcome variables were statistically significant between both surgical approaches. No differences were detected in terms of using a two-step surgical approach versus the one-step standard surgical approach regarding perioperative blood loss, surgical time, or complications. Level of evidence III.

  9. Improving the two-step remediation process for CCA-treated wood. Part I, Evaluating oxalic acid extraction

    Science.gov (United States)

    Carol Clausen

    2004-01-01

    In this study, three possible improvements to a remediation process for chromated-copper-arsenate (CCA) treated wood were evaluated. The process involves two steps: oxalic acid extraction of wood fiber followed by bacterial culture with Bacillus licheniformis CC01. The three potential improvements to the oxalic acid extraction step were (1) reusing oxalic acid for...

  10. Multivariate modelling of the pharmaceutical two-step process of wet granulation and tableting with multiblock partial least squares

    NARCIS (Netherlands)

    Westerhuis, J.A; Coenegracht, P.M J

    1997-01-01

    The pharmaceutical process of wet granulation and tableting is described as a two-step process. Besides the process variables of both steps and the composition variables of the powder mixture, the physical properties of the intermediate granules are also used to model the crushing strength and

  11. Effects of Mg Addition with Natural Aging Time on Two-Step Aging Behavior in Al-Mg-Si Alloys.

    Science.gov (United States)

    Im, Jiwoo; Kim, JaeHwang

    2018-03-01

    Influence of Mg contents with the natural aging (NA) time on the two-step aging behavior in Al-Mg-Si alloys is studied. Hardness is gradually increased during NA in the 3M4S, whereas dramatic increase of hardness after NA for 3.6 ks is confirmed in the 9M4S. Similar peak hardness is confirmed between the two-step aged and single aged samples in the 3M4S. It means that there is no negative effect of two-step aging. On the other hand, the peak hardness is decreased for the naturally-aged sample compared with the single aged one in the 9M4S. Formation of Cluster (1) is accelerated by the Mg addition, resulting in the negative effect of two-step aging. Meanwhile, the formation of the precipitates is accelerated by Mg addition during aging at 170 °C. The precipitate formed at the peak hardness during aging at 170 °C after natural aging for 43.2 ks is identified as the β″ phase based on the high resolution transmission electron microscope observation.

  12. Two-step method for creating a gastric tube during laparoscopic-thoracoscopic Ivor-Lewis esophagectomy.

    Science.gov (United States)

    Liu, Yu; Li, Ji-Jia; Zu, Peng; Liu, Hong-Xu; Yu, Zhan-Wu; Ren, Yi

    2017-12-07

    To introduce a two-step method for creating a gastric tube during laparoscopic-thoracoscopic Ivor-Lewis esophagectomy and assess its clinical application. One hundred and twenty-two patients with middle or lower esophageal cancer who underwent laparoscopic-thoracoscopic Ivor-Lewis esophagectomy at Liaoning Cancer Hospital and Institute from March 2014 to March 2016 were included in this study, and divided into two groups based on the procedure used for creating a gastric tube. One group used a two-step method for creating a gastric tube, and the other group used the conventional method. The two groups were compared regarding the operating time, surgical complications, and number of stapler cartridges used. The mean operating time was significantly shorter in the two-step method group than in the conventional method group [238 (179-293) min vs 272 (189-347) min, P two groups. The two-step method for creating a gastric tube during laparoscopic-thoracoscopic Ivor-Lewis esophagectomy has the advantages of simple operation, minimal damage to the tubular stomach, and reduced use of stapler cartridges.

  13. Transmission Electron Microscopy Study of Defect Reduction in Two-Step Lateral Epitaxial Overgrown Nonplanar GaN Substrate Templates

    National Research Council Canada - National Science Library

    Zhou, Wei; Ren, Dawei; Dapkus, P. D

    2005-01-01

    ...). The LEO nonplanar GaN substrate template has a trapezoidal cross section with smooth (0 0 0 1) and f11 22g facets. We demonstrate here the dislocation distribution and behavior in both ordinary LEO and two-step LEO...

  14. High efficiency two-step evaporator in a cooling system; Hocheffiziente zweistufige Verdampfung in einer Kaelteanlage - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Meister, R.; Haenni, E. [BMS-Energieanlagen AG, Wilderswil (Switzerland)

    2005-07-01

    A two-step evaporator was installed in parallel in an existing refrigeration plant with an operating capacity Q{sub o} of 130 kW. This ensured the possibility of a practical comparison between conventional evaporation and our high-efficiency two-step evaporator, without having to resort only to theoretical data. The result of this virtually one-on-one comparison in identical ambient conditions (which is not normally possible, as two systems cannot generally be installed in parallel) has confirmed what the advance calculations demonstrated, i.e. a 10% improvement in performance provided by the high-efficiency two-step evaporator. Thanks to the changeover from semi-floated to overflow operation (only tested in winter) it was possible, again as shown in previous calculations, to achieve an additional increase in performance of 5%. A basic objective was to use the high-efficiency two-step evaporator to provide stable performance in any operating situation - i.e. even after defrosting. This objective was achieved in both operating modes: semi-floated and overflow. Summer operation in overflow mode remains to be tested however, as the system has only been running in this mode since November 2004. (author)

  15. Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

    Energy Technology Data Exchange (ETDEWEB)

    Takashiri, Masayuki, E-mail: takashiri@tokai-u.jp; Kurita, Kensuke [Department of Materials Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Hagino, Harutoshi; Miyazaki, Koji [Department of Mechanical and Control Engineering, Kyushu Institute of Technology, 1-1 Sensui, Tobata-ku, Kitakyushu 804-8550 (Japan); Tanaka, Saburo [Department of Mechanical Engineering, College of Engineering, Nihon University, 1 Nakagawara, Tokusada, Tamuramachi, Koriyama, Fukushima 963-8642 (Japan)

    2015-08-14

    A two-step method that combines homogeneous electron beam (EB) irradiation and thermal annealing has been developed to enhance the thermoelectric properties of nanocrystalline bismuth selenium telluride thin films. The thin films, prepared using a flash evaporation method, were treated with EB irradiation in a N{sub 2} atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed under Ar/H{sub 2} (5%) at 300 °C for 60 min. X-ray diffraction was used to determine that compositional phase separation between bismuth telluride and bismuth selenium telluride developed in the thin films exposed to higher EB doses and thermal annealing. We propose that the phase separation was induced by fluctuations in the distribution of selenium atoms after EB irradiation, followed by the migration of selenium atoms to more stable sites during thermal annealing. As a result, thin film crystallinity improved and mobility was significantly enhanced. This indicates that the phase separation resulting from the two-step method enhanced, rather than disturbed, the electron transport. Both the electrical conductivity and the Seebeck coefficient were improved following the two-step method. Consequently, the power factor of thin films that underwent the two-step method was enhanced to 20 times (from 0.96 to 21.0 μW/(cm K{sup 2}) that of the thin films treated with EB irradiation alone.

  16. Obstructive Sleep Apnea Syndrome in Company Workers: Development of a Two-Step Screening Strategy with a New Questionnaire

    NARCIS (Netherlands)

    Eijsvogel, Michiel M.; Wiegersma, Sytske; Randerath, Winfried; Verbraecken, Johan; Wegter-Hilbers, Esther; van der Palen, Jacobus Adrianus Maria

    2016-01-01

    STUDY OBJECTIVES: To develop and evaluate a screening questionnaire and a two-step screening strategy for obstructive sleep apnea syndrome (OSAS) in healthy workers. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: A total of 1,861 employees comprising healthy blue- and white-collar workers

  17. Evaluation of Radiographic Results Obtained by Using Modified Dual Pelvic Osteotomy (DPO Plate for the Treatment of Hip Dysplasia in Dogs

    Directory of Open Access Journals (Sweden)

    Murat KARABAĞLI

    2017-07-01

    Full Text Available Hip dysplasia is a developmental orthopedic joint disease that commonly effects many different dog breeds, which are generally observed bilaterally. Triple pelvic osteotomy (TPO is one of the most common techniques used to minimize the development of joint subluxation and hip dysplasia in young dogs. However, in the course of time, different ways to reduce the complications of TPO have been described and alternative techniques such as dual pelvic osteotomy (DPO have been developed. Materials of our study consisted of 12 dogs with hip dysplasia at 7-11 months age range. Six of these dogs were selected from the dogs for 7-9 months old while the other six were selected for dogs at the age of 10-11 months old. In operation, pubic osteotomy was performed initially and then modified DPO plates were placed in ilium following ilium osteotomy. In acute postoperative period, patients were evaluated for ischiadic nerve paralysis symptoms. Preoperative Norberg angle measurements were compared with Norberg angle measurements on ventrodorsal pelvis graphs taken at postoperative 2nd month. As a result, it was observed that DPO was effective in slowing the development of hip dysplasia in the older patient population than 4.5-9 months old. No signs of postoperative ischiadic paralysis or paresis were seen in the patients. No complications such as screw loosening and plate breakage like complications related to the modified DPO plate which we used were encountered.

  18. The Weil osteotomy for treatment of dislocated lesser metatarsophalangeal joints: good outcome in 21 patients with 42 osteotomies.

    Science.gov (United States)

    Trnka, Hans-Jörg; Gebhard, Christoph; Mühlbauer, Michaela; Ivanic, Gerd; Ritschl, Peter

    2002-04-01

    Hardly any surgical methods are available for metatarsalgia caused by a dislocated lesser metatarsophalangeal joint (MTP) that do not sacrifice the joint. We reviewed retrospectively the outcome of 60 metatarsal Weil osteotomies for correction of dislocated lesser MTP joints in 31 patients. Between 1995 and 1996, 31 consecutive patients were treated with a Weil osteotomy at 2 institutions. The Weil osteotomy is an oblique osteotomy of the metatarsal neck and shaft, parallel to the ground surface, that controls shortening of the metatarsal by internal fixation with screws or pins. At an average final follow-up of 30 (24-44) months, all patients were interviewed, using a standardized questionnaire based on the AOFAS Lesser Metatarsophalangeal-Interphalangeal Scale. Recurrent or transfer metatarsalgia, formation of callus, mobility and dislocation of the MTP were noted on physical examination. Dorsoplantar and lateral weightbearing radiographs taken preoperatively and at the time of final follow-up were examined for alignment of the metatarsal heads, subluxation or dislocation and for evidence of nonunion, or malunion of the metatarsal osteotomy. We had excellent results in 21 patients (42 osteotomies). A major complication was plantar penetrating hardware in 10 cases (3 screws and 7 pins). We conclude that the Weil osteotomy is a good method for correcting metatarsalgia caused by dislocation of the MTP joint.

  19. Effectiveness of Percutaneous Proximal Closing Wedge Osteotomy With Akin Osteotomy to Correct Severe Hallux Valgus Determined by Radiographic Parameters.

    Science.gov (United States)

    Kurashige, Toshinori; Suzuki, Seiichi

    2017-04-01

    Some authors reported the results from percutaneous distal metatarsal osteotomy for hallux valgus recently. On the other hand, there are few reports of percutaneous proximal metatarsal osteotomy. The purpose of the present study was to evaluate the radiographic results of percutaneous proximal closing wedge osteotomy with Akin osteotomy for correction of severe hallux valgus and increasing longitudinal arch height. Consecutive 17 feet (mean age = 70.8 years) were investigated. The mean follow-up was 22 months. Excision of medial eminence, distal soft tissue release, and Akin osteotomy were all performed percutaneously and concurrently. Weight-bearing anteroposterior and lateral radiographs of the feet were acquired preoperatively and at final follow-up. On the anteroposterior radiographs, hallux valgus angle, intermetatarsal angle, and first metatarsal shortening were measured. On the lateral radiographs, talometatarsal angle, calcaneal pitch angle, and first metatarsal dorsiflexion were measured. The average improvements in hallux valgus angle and intermetatarsal angle were 27.6° and 9.9°, respectively. The average first metatarsal shortening was 2.7 mm. The first metatarsal dorsiflexion improved by 2.2°; however, other parameters did not improve significantly. In conclusion, percutaneous proximal closing wedge osteotomy with Akin osteotomy corrects severe hallux valgus; however, the procedure does not increase the medial longitudinal arch. Therapeutic, Level IV: Case series.

  20. Efficacy of Bilateral Simultaneous Hallux Valgus Correction Compared to Unilateral.

    Science.gov (United States)

    Boychenko, Anton Viktorovich; Solomin, Leonid Nikolaevich; Parfeyev, Sergey Gennadievich; Obukhov, Ilya Esatovich; Belokrylova, Maria Sergeevna; Davidov, Denis Vladimirovich

    2015-11-01

    Hallux valgus affects up to 29% of adults and can be bilateral in 84% of cases. Contemporary surgical techniques provide the possibility of simultaneous bilateral correction, but still there is no consensus on whether staged or simultaneous correction should be performed if both feet are involved. The aim of the present study was to report our experience of treatment of patients with hallux valgus and to perform comparative analysis of results obtained from unilateral and simultaneous bilateral surgical correction. Data on 60 feet (40 patients) with hallux valgus that underwent surgery between 2010 and 2013 using scarf osteotomy and lateral soft tissue release were analyzed. Unilateral correction was performed in 30 feet (25 patients) and bilateral correction in 30 feet (15 patients). The patients from both groups were admitted to hospital for 7 days. Functional assessment (American Orthopaedic Foot & Ankle Society [AOFAS] score) and radiographic examination (intermetatarsal and hallux valgus angles) were performed preoperatively and at 6, 12, and 24 months after the procedure. Comparative analysis between groups with bilateral and unilateral correction was carried out. At 24 months after surgery in the bilateral and unilateral groups, the mean AOFAS score was 86 ± 6.2 and 86 ± 6.9 (P > .05), the mean intermetatarsal angle was 8.4 ± 0.5 and 8.8 ± 0.8 degrees (P > .05), and the mean metatarsophalangeal angle was 13.0 ± 1.2 and 13.0 ± 0.9 degrees (P > .05), respectively. According to the data obtained, simultaneous bilateral correction had the same functional and radiographic results as unilateral surgery. Level III, case series. © The Author(s) 2015.

  1. Pregnancy following bilateral salpingectomy

    DEFF Research Database (Denmark)

    Oturai, Annette Bang

    2008-01-01

    This report presents a rare case of spontaneous pregnancy following bilateral salpingectomy. A woman with a history of bilateral salpingectomy was admitted to hospital because of abdominal pain and positive urine HCG. Surprisingly, ultrasound confirmed a live intrauterine fetus. The pregnancy...

  2. Computer-aided diagnosis of pulmonary nodules using a two-step approach for feature selection and classifier ensemble construction.

    Science.gov (United States)

    Lee, Michael C; Boroczky, Lilla; Sungur-Stasik, Kivilcim; Cann, Aaron D; Borczuk, Alain C; Kawut, Steven M; Powell, Charles A

    2010-09-01

    Accurate classification methods are critical in computer-aided diagnosis (CADx) and other clinical decision support systems. Previous research has reported on methods for combining genetic algorithm (GA) feature selection with ensemble classifier systems in an effort to increase classification accuracy. In this study, we describe a CADx system for pulmonary nodules using a two-step supervised learning system combining a GA with the random subspace method (RSM), with the aim of exploring algorithm design parameters and demonstrating improved classification performance over either the GA or RSM-based ensembles alone. We used a retrospective database of 125 pulmonary nodules (63 benign; 62 malignant) with CT volumes and clinical history. A total of 216 features were derived from the segmented image data and clinical history. Ensemble classifiers using RSM or GA-based feature selection were constructed and tested via leave-one-out validation with feature selection and classifier training executed within each iteration. We further tested a two-step approach using a GA ensemble to first assess the relevance of the features, and then using this information to control feature selection during a subsequent RSM step. The base classification was performed using linear discriminant analysis (LDA). The RSM classifier alone achieved a maximum leave-one-out Az of 0.866 (95% confidence interval: 0.794-0.919) at a subset size of s=36 features. The GA ensemble yielded an Az of 0.851 (0.775-0.907). The proposed two-step algorithm produced a maximum Az value of 0.889 (0.823-0.936) when the GA ensemble was used to completely remove less relevant features from the second RSM step, with similar results obtained when the GA-LDA results were used to reduce but not eliminate the occurrence of certain features. After accounting for correlations in the data, the leave-one-out Az in the two-step method was significantly higher than in the RSM and the GA-LDA. We have developed a CADx system for

  3. Short-term effects of proximal femoral derotation osteotomy on kinematics in ambulatory patients with spastic diplegia.

    Science.gov (United States)

    Kwon, Dae Gyu; Lee, Seung Yeol; Kim, Tae Won; Chung, Chin Youb; Lee, Kyoung Min; Sung, Ki Hyuk; Akhmedov, Bekhzad; Choi, In Ho; Cho, Tae-Joon; Yoo, Won Joon; Park, Moon Seok

    2013-05-01

    The aim of this retrospective study was to determine the short-term effects of proximal femoral derotation osteotomy (FDO) on gait in 53 ambulatory patients with spastic diplegia controlling all confounding procedures. All patients showed a jump gait pattern and had undergone bilateral rectus femoris transfer, distal hamstring lengthening, and tendo-Achilles lengthening as a single-event multilevel surgery. Of these, additional bilateral proximal FDOs were included in 25 patients, defined as the FDO group; the other 28 patients were defined as the no-FDO group. Kinematic variables, such as pelvic tilt, minimal hip flexion in stance, hip rotation, and foot progression angle, were compared between the two groups at postoperative 1 year. Hip extension, hip rotation, and hip adduction improved significantly after surgery in the FDO group (Pspastic diplegia showing a jump gait.

  4. Radial head dislocation during proximal radial shaft osteotomy.

    Science.gov (United States)

    Hazel, Antony; Bindra, Randy R

    2014-03-01

    The following case report describes a 48-year-old female patient with a longstanding both-bone forearm malunion, who underwent osteotomies of both the radius and ulna to improve symptoms of pain and lack of rotation at the wrist. The osteotomies were templated preoperatively. During surgery, after performing the planned radial shaft osteotomy, the authors recognized that the radial head was subluxated. The osteotomy was then revised from an opening wedge to a closing wedge with improvement of alignment and rotation. The case report discusses the details of the operation, as well as ways in which to avoid similar shortcomings in the future. Copyright © 2014 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  5. Osteochondritis dissecans after rotational acetabular osteotomy for dysplastic hip

    Energy Technology Data Exchange (ETDEWEB)

    Nozawa, Masahiko; Maezawa, Katsuhiko; Yuasa, Takahito; Morimoto, Kouichi; Asakura, Taro; Kurosawa, Hisashi [Juntendo University School of Medicine, Department of Orthopaedic Surgery, Tokyo (Japan)

    2005-12-01

    We encountered a rare case of osteochondritis dissecans of the femoral head after rotational acetabular osteotomy that recovered with conservative treatment 4 years after the detection of characteristic radiological findings. (orig.)

  6. The True Ponte Osteotomy: By the One Who Developed It.

    Science.gov (United States)

    Ponte, Alberto; Orlando, Giuseppe; Siccardi, Gian Luigi

    2018-01-01

    Technique and applications. To define the anatomy, biomechanics, indications, and surgical technique of the true Ponte osteotomy. The Ponte osteotomy, originally developed for thoracic kyphosis, was the first one to obtain posterior shortening of the thoracic spine, maintaining the anterior column load-sharing capacity. It has become a widely applied technique in various types of spine deformities and a frequent topic of presentations at meetings and in scientific articles. Several of them offer unquestionable evidence of an incorrect execution, with consequently distorted outcomes and erroneous conclusions. A clearing up became essential. Our original experience is based on a series of 240 patients with thoracic hyperkyphosis operated in the years 1969-2015, at first with a standard posterior Harrington technique and then by using the Ponte osteotomy with different instrumentations. A series of 78 of them, operated in the years 1987-1997, who had Ponte osteotomies at every level, is presented. The average preoperative kyphosis has been corrected from 80° (range 61°-102°) to 31° (range 15°-50°) by a substantial posterior shortening. A number of publications use the term Ponte osteotomy loosely for by far incomplete resections and mixing it up with Smith-Petersen's osteotomy. The true Ponte osteotomy is capable of producing marked flexibility in extension, flexion and rotation, justifying its wide use in thoracic deformities, mainly in scoliosis. An exact performance of the osteotomy with adequate bony resections, including the laminae, is an absolute condition to take full advantage of its properties. Level IV, therapeutic study. Copyright © 2017 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.

  7. Minimal Incision/Minimally Invasive Medializing Displacement Calcaneal Osteotomy.

    Science.gov (United States)

    Sherman, Thomas I; Guyton, Gregory P

    2018-01-01

    Minimally invasive techniques are readily applicable to calcaneal osteotomies and have the potential to accomplish hindfoot correction equivalent to open procedures with less morbidity and pain. Use of a guidance jig makes the procedure more predictable. While most anatomic features of the procedure are the same as those with open techniques, special care must be taken to avoid neurovascular injury because there is no open exposure. Anatomic guidelines have been established for appropriately localizing the osteotomy. Level V, expert opinion.

  8. Fatigue Damage Evaluation of Friction Stir Spot Welded Cross-Tension Joints Under Repeated Two-Step Force Amplitudes

    Science.gov (United States)

    Joy-A-Ka, Sutep; Ogawa, Yuki; Akebono, Hiroyuki; Kato, Masahiko; Sugeta, Atsushi; Sun, Yufeng; Fujii, Hidetoshi

    2015-06-01

    This paper investigates an approach to evaluate the fatigue damage of FSSW cross-tension specimens under two-step force amplitude conditions. In fatigue tests with repeated two-step force amplitude, the fatigue limit of the welded joint disappeared. However, the fatigue damage evaluation using the modified Miner's rule erred too much on the side of safety, as the modified Miner's rule tends to overestimate the damage by applied forces below the fatigue limit. Thus, it was determined that, within the testing conditions used in this study, the fatigue damage evaluation using Haibach's method yielded an accurate evaluation. In the case where significant plastic deformation caused by the applied force occurred near the welded zone, the cumulative fatigue damage value based on Miner's rule was often larger than unity. Therefore, it is important to consider a cumulative damage estimation that takes into account the effect of pre-strain from the high force amplitude.

  9. Dynamic expression reveals a two-step patterning of WUS and CLV3 during axillary shoot meristem formation in Arabidopsis.

    Science.gov (United States)

    Xin, Wei; Wang, Zhicai; Liang, Yan; Wang, Yonghong; Hu, Yuxin

    2017-07-01

    Seed plants have a remarkable capability to produce axillary meristems (AM) in the leaf axils, however, the dynamic establishment of a stem cell niche in AM is largely uncharacterized. We comprehensively examined the dynamic patterning of WUSCHEL (WUS) and CLAVATA3 (CLV3), the two key marker genes defining the shoot stem cell niches, during AM formation in Arabidopsis, and we found that a two-step patterning of WUS and CLV3 occurred during AM stem cell niche establishment. Our further work on the wus and clv3 mutants implicates that such two-step patterning is likely critical for the maintenance of AM progenitor cells and the specification of AM stem cell niche. These data provide a cytological frame for how a stem cell niche is established during AM formation. Copyright © 2017 Elsevier GmbH. All rights reserved.

  10. A two-step annealing process for enhancing the ferroelectric properties of poly(vinylidene fluoride) (PVDF) devices

    KAUST Repository

    Park, Jihoon

    2015-01-01

    We report a simple two-step annealing scheme for the fabrication of stable non-volatile memory devices employing poly(vinylidene fluoride) (PVDF) polymer thin-films. The proposed two-step annealing scheme comprises the crystallization of the ferroelectric gamma-phase during the first step and enhancement of the PVDF film dense morphology during the second step. Moreover, when we extended the processing time of the second step, we obtained good hysteresis curves down to 1 Hz, the first such report for ferroelectric PVDF films. The PVDF films also exhibit a coercive field of 113 MV m-1 and a ferroelectric polarization of 5.4 μC cm-2. © The Royal Society of Chemistry 2015.

  11. Two-step purification of a highly thermostable alkaline protease from salt-tolerant alkaliphilic Streptomyces clavuligerus strain Mit-1.

    Science.gov (United States)

    Thumar, Jignasha; Singh, S P

    2007-07-01

    An alkaline protease from a salt-tolerant alkaliphilic Streptomyces clavuligerus was purified to homogeneity by 141-fold with a yield of 12% using two-step method of salt precipitation and ion exchange chromatography on DEAE cellulose. The apparent molecular mass was 49+/-2 kDa and the enzyme appeared as monomer based on SDS and Native-PAGE. The temperature optimum was 70 degrees C with significant stability at 60-80 degrees C for more than 60 min. The enzyme was active over the pH range of 8.5-11, with an optimum at 10-11. The serine nature of the protease was confirmed by PMSF inhibition. The enzyme was highly resistant against chemical denaturation and displayed varied effects towards metal ions. The results are significant as extremozymes are difficult to purify and therefore, a two-step purification of alkaline protease from relatively less explored group of actinomycetes is quite appealing.

  12. A sequential two-step near-infrared quantum splitting in Ho3+ singly doped NaYF4

    Directory of Open Access Journals (Sweden)

    D. C. Yu

    2011-12-01

    Full Text Available We demonstrated an efficient sequential two-step near-infrared (NIR quantum splitting (QS in a Ho3+ singly doped β-NaYF4. An incident high-energy ultraviolet (UV-to-visible photon in the wavelength range of 300−560 nm, which enables the Ho3+:5F4,5S2 states excited, could be efficiently split into two NIR photons at 1015 and 1180 nm. Underlying mechanisms for the sequential two-step NIR-QS process are analyzed in terms of the diffuse reflection spectrum, static and dynamic photoemission spectra and monitored excitation spectra. Internal quantum yield is obtained up to 110% on the basis of experimental and theoretical calculation results.

  13. Two-step purification of scutellarin from Erigeron breviscapus (vant.) Hand. Mazz. by high-speed counter-current chromatography.

    Science.gov (United States)

    Gao, Min; Gu, Ming; Liu, Chun-Zhao

    2006-07-11

    Scutellarin, a flavone glycoside, popularly applied for the treatment of cardiopathy, has been purified in two-step purification by high-speed counter-current chromatography (HSCCC) from Erigeron breviscapus (vant.) Hand. Mazz. (Deng-zhan-hua in Chinese), a well-known traditional Chinese medicinal plant for heart disease. Two solvent systems, n-hexane-ethyl acetate-methanol-acetic acid-water (1:6:1.5:1:4, v/v/v/v/v) and ethyl acetate-n-butanol-acetonitrile-0.1% HCl (5:2:5:10, v/v/v/v) were used for the two-step purification. The purity of the collected fraction of scutellarin was 95.6%. This study supplies a new alternative method for purification of scutellarin.

  14. A simple two-step purification procedure for the iC3b binding collectin conglutinin

    DEFF Research Database (Denmark)

    Krogh-Meibom, Thomas; Ingvartsen, Klaus Lønne; Tornoe, Ida

    2010-01-01

    Bovine conglutinin is a serum protein involved in innate immunity. It binds calcium dependently to iC3b, a product of the complement component C3 deposited on cell surfaces, immune complexes or artificial surfaces after complement activation. We here present a simple and efficient two-step proced......M). SDS-PAGE and time-resolved immunofluorometric assays showed that the conglutinin was not contaminated with other serum collectins such as collectin-43 or mannan-binding lectin....

  15. Two step novel hydrogen system using additives to enhance hydrogen release from the hydrolysis of alane and activated aluminum

    Science.gov (United States)

    Zidan, Ragaiy; Teprovich, Joseph A.; Motyka, Theodore

    2015-12-01

    A system for the generation of hydrogen for use in portable power systems is set forth utilizing a two-step process that involves the thermal decomposition of AlH.sub.3 (10 wt % H.sub.2) followed by the hydrolysis of the activated aluminum (Al*) byproduct to release additional H.sub.2. Additionally, a process in which water is added directly without prior history to the AlH.sub.3:PA composite is also disclosed.

  16. Development of Two-Step Temperature Process to Modulate the Physicochemical Properties ofβ-lactoglobulin Nanoparticles.

    Science.gov (United States)

    Ha, Ho-Kyung; Nam, Gyeong-Won; Khang, Dongwoo; Park, Sung Jean; Lee, Mee-Ryung; Lee, Won-Jae

    2017-01-01

    The development of a new manufacturing process, a two-step temperature treatment, to modulate the physicochemical properties of nanoparticles including the size is critical. This is because its physicochemical properties can be key factors affecting the cellular uptake and the bioavailability of bioactive compounds encapsulated in nanoparticles. The aims of this study were to produce (beta-lactoglobulin) β -lg nanoparticles and to understand how two-step temperature treatment could affect the formation and physicochemical properties of β -lg nanoparticles. The morphological and physicochemical properties of β -lg nanoparticles were determined using atomic force microscopy and a particle size analyzer, respectively. Circular dichroism spectroscopy was used to investigate the secondary structure of β -lg. The surface hydrophobicity and free thiol groups of β -lg were increased with a decrease in sub-ambient temperature and an increase in mild heat temperature. As sub-ambient temperature was decreased, a decrease in α -helical content and an increase in β -sheet content were observed. The two-step temperature treatment firstly involved a sub-ambient temperature treatment from 5 to 20°C for 30 min, followed secondly by a mild heat temperature treatment from 55 to 75°C for 10 min. This resulted in the production of spherically-shaped particles with a size ranging from 61 to 214 nm. Two-way ANOVA exhibited the finding that both sub-ambient and mild heat temperature significantly ( p two-step temperature treatment was shown to play an important role in the manufacturing process - both due to its inducement of the conformational changes of β -lg during nanoparticle formation, and due to its modulation of the physicochemical properties of β -lg nanoparticles.

  17. A two-step method for variable selection in the analysis of a case-cohort study.

    Science.gov (United States)

    Newcombe, P J; Connolly, S; Seaman, S; Richardson, S; Sharp, S J

    2017-11-10

    Accurate detection and estimation of true exposure-outcome associations is important in aetiological analysis; when there are multiple potential exposure variables of interest, methods for detecting the subset of variables most likely to have true associations with the outcome of interest are required. Case-cohort studies often collect data on a large number of variables which have not been measured in the entire cohort (e.g. panels of biomarkers). There is a lack of guidance on methods for variable selection in case-cohort studies. We describe and explore the application of three variable selection methods to data from a case-cohort study. These are: (i) selecting variables based on their level of significance in univariable (i.e. one-at-a-time) Prentice-weighted Cox regression models; (ii) stepwise selection applied to Prentice-weighted Cox regression; and (iii) a two-step method which applies a Bayesian variable selection algorithm to obtain posterior probabilities of selection for each variable using multivariable logistic regression followed by effect estimation using Prentice-weighted Cox regression. Across nine different simulation scenarios, the two-step method demonstrated higher sensitivity and lower false discovery rate than the one-at-a-time and stepwise methods. In an application of the methods to data from the EPIC-InterAct case-cohort study, the two-step method identified an additional two fatty acids as being associated with incident type 2 diabetes, compared with the one-at-a-time and stepwise methods. The two-step method enables more powerful and accurate detection of exposure-outcome associations in case-cohort studies. An R package is available to enable researchers to apply this method. © The Author 2017. Published by Oxford University Press on behalf of the International Epidemiological Association.

  18. Network diversity through decoration of trigonal-prismatic nodes: Two-step crystal engineering of cationic metal-organic materials

    KAUST Repository

    Schoedel, Alexander

    2011-10-05

    MOMs the word! In a two-step process, first a trigonal-prismatic Primary Molecular Building Block ([Cr3O(isonic)6]+, tp-PMBB-1) was formed and then it was connected to linear linkers or square-planar nodes to afford three novel highly charged cationic metal-organic materials (MOMs) with snx, snw, and stp topologies. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Enhanced age-strengthening by two-step progressive solution treatment in an Mg–Zn–Al–Re alloy

    International Nuclear Information System (INIS)

    Zhang, Jing; Yuan, Fuqing; Du, Yong

    2013-01-01

    Highlights: • A two-step progressive solution treatment schedule was proposed. • The treatment enhanced dissolution of ternary eutectic phases in Mg–Zn–Al alloy. • Solution temperature could break the limit of the ternary eutectic temperature. • There was no microstructural over-heating defect during the progressive heating. • The τ precipitates have a remarkable dispersion strengthening effect. - Abstract: A two-step progressive solution treatment was designed and performed on an as-extruded Mg–7Zn–3Al–0.7Er alloy. The resultant microstructure and mechanical properties were examined by means of scanning electron microscopy, X-ray diffractometer, differential scanning calorimetry and hardness testing. The results showed that the two-step progressive solution treatment could enhance the dissolution of the ternary eutectic phases in the Mg–Zn–Al system without the formation of microstructure over-heating defects. After homogenization for 50 h at 325 °C, the volume fraction of the undissolved particles in the Mg–7Zn–3Al–0.7Er alloy ingot was ∼4.1%. Two-step progressive solution treatment performed on the as-extruded alloy could further dissolve the particles. Only 1.5% undissolved particles remained after the treatment. The supersaturated degree of both the dissolved solute atoms and vacancies in the α-Mg matrix was expected to be increased, resulting in an enhanced age-strengthening, compared with normal solution and aging treatments. Moreover, the processed alloy exhibited a homogenous and stable fine grain structure. Remarkable dispersion strengthening effect of ternary τ (Mg 32 (Al,Zn) 49 ) precipitates occurred in Mg–Zn–Al alloy was also identified

  20. The Comparison of One and Two Steps Equilibration in Vitrification Process on The Morphology and Viability of Mouse Blastocysts

    Directory of Open Access Journals (Sweden)

    Ita Djuwita

    2010-09-01

    Full Text Available A study was conducted to compare the effect of one and two steps equilibration method of vitrificationon the morphology and viability of mouse blastocysts. Blastocysts were firstly exposed to modified PhosphateBuffered saline (mPBS containing 1% Bovine Serum Albumin (BSA proceeded by exposure in mPBSrespectively containing 0.25M sucrose (S for 2 minutes . Blastocysts were then exposed for 2 minutesrespectively to mPS+0.5M S (one step method or in mPBS+0.5M S+10% ethylene glycol (EG (two stepmethod.. Blastocysts were then exposed in mPBS+0.5M S+30% EG for 60 second, loaded into 0.25 mlplastic straw, and exposed immediately in vapor of liquid nitrogen for 10 second before they were and thenplunged into liquid nitrogen. The blastocysts were reconstituted by diluting with mPBS+0.5M S followedby mPBS+0.25M S for each 3 min and washed in mPBS without sucrose. The viability of cells was assessedby fluorescent vital staining, by re-expansion for 24 hours in vitro culture, and by implantation into therecipient oviduct. The percentages of morphologically normal blastocysts following recovery fromvitrification were higher (p<0.05 in one step equilibration than in those of two steps methods (89.6%. vs82.6%. The viability of blastocysts examined under light microscope after staining with biz-benzimidizepropidiumiodine and 24 hours in vitro culture in one step methods (64.0%; 57.8% were higher (p<0.05compared with two steps methods (40.0%; 35.6%, respectively. The implantation rate of vitrifiedblastocysts (23.1% was not significantly different to that of fresh blastocysts (33.4%. These resultsshowed that the one and two step equilibration methods are effective for vitrification and maintaining theviability of the mouse blastocysts.

  1. Comparison between the two-step and the three-step algorithms for the detection of toxigenic Clostridium difficile.

    Science.gov (United States)

    Qutub, M O; AlBaz, N; Hawken, P; Anoos, A

    2011-01-01

    To evaluate usefulness of applying either the two-step algorithm (Ag-EIAs and CCNA) or the three-step algorithm (all three assays) for better confirmation of toxigenic Clostridium difficile. The antigen enzyme immunoassays (Ag-EIAs) can accurately identify the glutamate dehydrogenase antigen of toxigenic and nontoxigenic Clostridium difficile. Therefore, it is used in combination with a toxin-detecting assay [cell line culture neutralization assay (CCNA), or the enzyme immunoassays for toxins A and B (TOX-A/BII EIA)] to provide specific evidence of Clostridium difficile-associated diarrhoea. A total of 151 nonformed stool specimens were tested by Ag-EIAs, TOX-A/BII EIA, and CCNA. All tests were performed according to the manufacturer's instructions and the results of Ag-EIAs and TOX-A/BII EIA were read using a spectrophotometer at a wavelength of 450 nm. A total of 61 (40.7%), 38 (25.3%), and 52 (34.7%) specimens tested positive with Ag-EIA, TOX-A/BII EIA, and CCNA, respectively. Overall, the sensitivity, specificity, negative predictive value, and positive predictive value for Ag-EIA were 94%, 87%, 96.6%, and 80.3%, respectively. Whereas for TOX-A/BII EIA, the sensitivity, specificity, negative predictive value, and positive predictive value were 73.1%, 100%, 87.5%, and 100%, respectively. With the two-step algorithm, all 61 Ag-EIAs-positive cases required 2 days for confirmation. With the three-step algorithm, 37 (60.7%) cases were reported immediately, and the remaining 24 (39.3%) required further testing by CCNA. By applying the two-step algorithm, the workload and cost could be reduced by 28.2% compared with the three-step algorithm. The two-step algorithm is the most practical for accurately detecting toxigenic Clostridium difficile, but it is time-consuming.

  2. Comparison between the two-step and the three-step algorithms for the detection of toxigenic Clostridium difficile

    Directory of Open Access Journals (Sweden)

    M O Qutub

    2011-01-01

    Full Text Available Purpose: To evaluate usefulness of applying either the two-step algorithm (Ag-EIAs and CCNA or the three-step algorithm (all three assays for better confirmation of toxigenic Clostridium difficile. The antigen enzyme immunoassays (Ag-EIAs can accurately identify the glutamate dehydrogenase antigen of toxigenic and nontoxigenic Clostridium difficile. Therefore, it is used in combination with a toxin-detecting assay [cell line culture neutralization assay (CCNA, or the enzyme immunoassays for toxins A and B (TOX-A/BII EIA] to provide specific evidence of Clostridium difficile-associated diarrhoea. Materials and Methods: A total of 151 nonformed stool specimens were tested by Ag-EIAs, TOX-A/BII EIA, and CCNA. All tests were performed according to the manufacturer′s instructions and the results of Ag-EIAs and TOX-A/BII EIA were read using a spectrophotometer at a wavelength of 450 nm. Results: A total of 61 (40.7%, 38 (25.3%, and 52 (34.7% specimens tested positive with Ag-EIA, TOX-A/BII EIA, and CCNA, respectively. Overall, the sensitivity, specificity, negative predictive value, and positive predictive value for Ag-EIA were 94%, 87%, 96.6%, and 80.3%, respectively. Whereas for TOX-A/BII EIA, the sensitivity, specificity, negative predictive value, and positive predictive value were 73.1%, 100%, 87.5%, and 100%, respectively. With the two-step algorithm, all 61 Ag-EIAs-positive cases required 2 days for confirmation. With the three-step algorithm, 37 (60.7% cases were reported immediately, and the remaining 24 (39.3% required further testing by CCNA. By applying the two-step algorithm, the workload and cost could be reduced by 28.2% compared with the three-step algorithm. Conclusions: The two-step algorithm is the most practical for accurately detecting toxigenic Clostridium difficile, but it is time-consuming.

  3. Theory of Square-Wave Voltammetry of Two-Step Electrode Reaction Using an Inverse Scan Direction

    Directory of Open Access Journals (Sweden)

    Milivoj Lovrić

    2011-01-01

    Full Text Available A theory of square-wave voltammetry of two-step electrode reaction with kinetically controlled electron transfers is developed, and a special case of thermodynamically unstable intermediate is analyzed. If the first reaction step is reversible and the second one is quasireversible, the response splits into two peaks if the scan direction is inverted. The separation of these peaks increases with frequency.

  4. Chiari pelvic osteotomy in treatment of hip dysplasia

    Directory of Open Access Journals (Sweden)

    Slavković Nemanja

    2013-01-01

    Full Text Available Chiari pelvic osteotomy is a surgical procedure having been performed for almost sixty years in patients with the insuffcient coverage of the femoral head. It is most frequently used in young patients with dysplastic acetabular sockets as a part of developmental hip dysplasia. Even though performance of the Chiari osteotomy is associated with positive therapeutical results, above all, its main goal is to delay inevitable degenerative changes. Original surgical technique has been modified and improved over time. Nevertheless, the basic idea has remained unchanged - increasing of the femoral head coverage by medial displacement of the distal part of the pelvis along with capsular interpositioning. Given the complexity of operation, the complication percentage is rather low. Chiari pelvic osteotomy has lost its actuality and importance during this past six decades. The role of Chiari pelvic osteotomy has been considerably taken over by other more efficient and more lasting surgical procedures. Nonetheless, Chiari pelvic osteotomy is still present in modern orthopedic practice, above all as „salvage“ osteotomy. [Projekat Ministarstva nauke Republike Srbije, br. 41004

  5. Two-Step Optimization for Spatial Accessibility Improvement: A Case Study of Health Care Planning in Rural China.

    Science.gov (United States)

    Luo, Jing; Tian, Lingling; Luo, Lei; Yi, Hong; Wang, Fahui

    2017-01-01

    A recent advancement in location-allocation modeling formulates a two-step approach to a new problem of minimizing disparity of spatial accessibility. Our field work in a health care planning project in a rural county in China indicated that residents valued distance or travel time from the nearest hospital foremost and then considered quality of care including less waiting time as a secondary desirability. Based on the case study, this paper further clarifies the sequential decision-making approach, termed "two-step optimization for spatial accessibility improvement (2SO4SAI)." The first step is to find the best locations to site new facilities by emphasizing accessibility as proximity to the nearest facilities with several alternative objectives under consideration. The second step adjusts the capacities of facilities for minimal inequality in accessibility, where the measure of accessibility accounts for the match ratio of supply and demand and complex spatial interaction between them. The case study illustrates how the two-step optimization method improves both aspects of spatial accessibility for health care access in rural China.

  6. Application of the Two-Step Filter to Process Ranging Measurements for Relative Navigation in an Elliptical Orbit

    Science.gov (United States)

    Garrison, James L.; Axelrad, Penina

    1997-01-01

    This estimator breaks a nonlinear estimation problem into a set of over determined 'first step' states which are linear in the observations and 'second step' states which are ultimately the states of interest. Linear estimation methods are applied to filter the observations and produce the optimal first step state estimate. The 'second step' states are obtained through iterative nonlinear parameter estimation considering the first step states as observations. It has been shown that this process exactly minimizes the least squares cost function for static problems and provides a better solution than the iterated extended Kalman filter (EKF) for dynamic problems. The two step filter is applied in this paper to process range and range rate measurements between the two spacecraft. Details of the application of the two step estimator to this problem will be given, highlighting the use of a test for ill-conditioned covariance estimates that can result from the first order covariance propagation. A comparison will be made between the performance of the two step filter and the IEKF.

  7. Efficient preparative separation of β-cypermethrin stereoisomers by supercritical fluid chromatography with a two-step combined strategy.

    Science.gov (United States)

    Yan, Yilun; Fan, Jun; Lai, Yecai; He, Jianfeng; Guo, Dong; Zhang, Hui; Zhang, Weiguang

    2017-12-20

    An efficient two-step method has been developed for the separation of β-cypermethrin stereoisomers by supercritical fluid chromatography with polysaccharide chiral stationary phases. With respect to retention, selectivity, and resolution of β-cypermethrin, the effects of chiral stationary phases, cosolvents, mobile phases, and column temperature have been studied in detail. Through a two-step separation, β-cypermethrin was firstly separated by using a cellulose-derived chiral stationary phase to obtain two stereoisomeric pairs, and further resolved on an amylose-based chiral stationary phase to produce four enantiopure stereoisomers. The electronic circular dichroism patterns of the first- and the third-eluted isomers in methanol solution showed the mirror image of each other in the wavelength range 200∼300 nm, indicating that they were a pair of enantiomers. Moreover, the second- and the fourth-eluted isomers were also enantiomers. This proposed two-step strategy showed low solvent consumption, fast separation speed, and high-purity, which may provide an effective approach for preparative separation of compounds with multiple chiral centers and difficult-to-separate multicomponent samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Improved Reproducibility for Perovskite Solar Cells with 1 cm2Active Area by a Modified Two-Step Process.

    Science.gov (United States)

    Shen, Heping; Wu, Yiliang; Peng, Jun; Duong, The; Fu, Xiao; Barugkin, Chog; White, Thomas P; Weber, Klaus; Catchpole, Kylie R

    2017-02-22

    With rapid progress in recent years, organohalide perovskite solar cells (PSC) are promising candidates for a new generation of highly efficient thin-film photovoltaic technologies, for which up-scaling is an essential step toward commercialization. In this work, we propose a modified two-step method to deposit the CH 3 NH 3 PbI 3 (MAPbI 3 ) perovskite film that improves the uniformity, photovoltaic performance, and repeatability of large-area perovskite solar cells. This method is based on the commonly used two-step method, with one additional process involving treating the perovskite film with concentrated methylammonium iodide (MAI) solution. This additional treatment is proved to be helpful for tailoring the residual PbI 2 level to an optimal range that is favorable for both optical absorption and inhibition of recombination. Scanning electron microscopy and photoluminescence image analysis further reveal that, compared to the standard two-step and one-step methods, this method is very robust for achieving uniform and pinhole-free large-area films. This is validated by the photovoltaic performance of the prototype devices with an active area of 1 cm 2 , where we achieved the champion efficiency of ∼14.5% and an average efficiency of ∼13.5%, with excellent reproducibility.

  9. DEVELOPMENT OF AN APPROXIMATE MULTIVARIATE TWO-STEP APPROACH FOR THE JOINT GENETIC EVALUATION OF AUSTRIAN AND GERMAN DAIRY CATTLE

    Directory of Open Access Journals (Sweden)

    Christina Pfeiffer

    2015-09-01

    Full Text Available Multivariate genetic evaluation in modern dairy cattle breeding programs became important in the last decades. The simultaneous estimation of all production and functional traits is still demanding. Different meta-models are used to overcome several constraints. The aim of this study was to conduct an approximate multivariate two-step procedure applied to de-regressed breeding values and yield deviations of five fertility traits of Austrian Pinzgau cattle and to compare results with routinely estimated breeding values. The approximate two-step procedure applied to de-regressed breeding values performed better than the procedure applied to yield deviations. Spearman rank correlations for all animals, sires and cows were between 0.996 and 0.999 for the procedure applied to de-regressed breeding values and between 0.866 and 0.995 for the procedure applied to yield deviations. The results are encouraging to move from the currently used selection index in routine genetic evaluation towards an approximate two-step procedure applied to de-regressed breeding values.

  10. Biomarker Selection and Classification of “-Omics” Data Using a Two-Step Bayes Classification Framework

    Directory of Open Access Journals (Sweden)

    Anunchai Assawamakin

    2013-01-01

    Full Text Available Identification of suitable biomarkers for accurate prediction of phenotypic outcomes is a goal for personalized medicine. However, current machine learning approaches are either too complex or perform poorly. Here, a novel two-step machine-learning framework is presented to address this need. First, a Naïve Bayes estimator is used to rank features from which the top-ranked will most likely contain the most informative features for prediction of the underlying biological classes. The top-ranked features are then used in a Hidden Naïve Bayes classifier to construct a classification prediction model from these filtered attributes. In order to obtain the minimum set of the most informative biomarkers, the bottom-ranked features are successively removed from the Naïve Bayes-filtered feature list one at a time, and the classification accuracy of the Hidden Naïve Bayes classifier is checked for each pruned feature set. The performance of the proposed two-step Bayes classification framework was tested on different types of -omics datasets including gene expression microarray, single nucleotide polymorphism microarray (SNParray, and surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF proteomic data. The proposed two-step Bayes classification framework was equal to and, in some cases, outperformed other classification methods in terms of prediction accuracy, minimum number of classification markers, and computational time.

  11. Two-Step Optimization for Spatial Accessibility Improvement: A Case Study of Health Care Planning in Rural China

    Directory of Open Access Journals (Sweden)

    Jing Luo

    2017-01-01

    Full Text Available A recent advancement in location-allocation modeling formulates a two-step approach to a new problem of minimizing disparity of spatial accessibility. Our field work in a health care planning project in a rural county in China indicated that residents valued distance or travel time from the nearest hospital foremost and then considered quality of care including less waiting time as a secondary desirability. Based on the case study, this paper further clarifies the sequential decision-making approach, termed “two-step optimization for spatial accessibility improvement (2SO4SAI.” The first step is to find the best locations to site new facilities by emphasizing accessibility as proximity to the nearest facilities with several alternative objectives under consideration. The second step adjusts the capacities of facilities for minimal inequality in accessibility, where the measure of accessibility accounts for the match ratio of supply and demand and complex spatial interaction between them. The case study illustrates how the two-step optimization method improves both aspects of spatial accessibility for health care access in rural China.

  12. Two-step relaxation mode analysis with multiple evolution times applied to all-atom molecular dynamics protein simulation

    Science.gov (United States)

    Karasawa, N.; Mitsutake, A.; Takano, H.

    2017-12-01

    Proteins implement their functionalities when folded into specific three-dimensional structures, and their functions are related to the protein structures and dynamics. Previously, we applied a relaxation mode analysis (RMA) method to protein systems; this method approximately estimates the slow relaxation modes and times via simulation and enables investigation of the dynamic properties underlying the protein structural fluctuations. Recently, two-step RMA with multiple evolution times has been proposed and applied to a slightly complex homopolymer system, i.e., a single [n ] polycatenane. This method can be applied to more complex heteropolymer systems, i.e., protein systems, to estimate the relaxation modes and times more accurately. In two-step RMA, we first perform RMA and obtain rough estimates of the relaxation modes and times. Then, we apply RMA with multiple evolution times to a small number of the slowest relaxation modes obtained in the previous calculation. Herein, we apply this method to the results of principal component analysis (PCA). First, PCA is applied to a 2-μ s molecular dynamics simulation of hen egg-white lysozyme in aqueous solution. Then, the two-step RMA method with multiple evolution times is applied to the obtained principal components. The slow relaxation modes and corresponding relaxation times for the principal components are much improved by the second RMA.

  13. Two-Step Delivery: Exploiting the Partition Coefficient Concept to Increase Intratumoral Paclitaxel Concentrations In vivo Using Responsive Nanoparticles

    Science.gov (United States)

    Colby, Aaron H.; Liu, Rong; Schulz, Morgan D.; Padera, Robert F.; Colson, Yolonda L.; Grinstaff, Mark W.

    2016-01-01

    Drug dose, high local target tissue concentration, and prolonged duration of exposure are essential criteria in achieving optimal drug performance. However, systemically delivered drugs often fail to effectively address these factors with only fractions of the injected dose reaching the target tissue. This is especially evident in the treatment of peritoneal cancers, including mesothelioma, ovarian, and pancreatic cancer, which regularly employ regimens of intravenous and/or intraperitoneal chemotherapy (e.g., gemcitabine, cisplatin, pemetrexed, and paclitaxel) with limited results. Here, we show that a “two-step” nanoparticle (NP) delivery system may address this limitation. This two-step approach involves the separate administration of NP and drug where, first, the NP localizes to tumor. Second, subsequent administration of drug then rapidly concentrates into the NP already stationed within the target tissue. This two-step method results in a greater than 5-fold increase in intratumoral drug concentrations compared to conventional “drug-alone” administration. These results suggest that this unique two-step delivery may provide a novel method for increasing drug concentrations in target tissues.

  14. Pregnancy following bilateral salpingectomy

    DEFF Research Database (Denmark)

    Oturai, Annette Bang

    2008-01-01

    This report presents a rare case of spontaneous pregnancy following bilateral salpingectomy. A woman with a history of bilateral salpingectomy was admitted to hospital because of abdominal pain and positive urine HCG. Surprisingly, ultrasound confirmed a live intrauterine fetus. The pregnancy...... was unwanted, and the woman decided to terminate the pregnancy. She was offered diagnostic examination to localise a potential fistula, but she declined. In a MEDLINE search of English literature this is only the second case of spontaneous pregnancy following bilateral salpingectomy Udgivelsesdato: 2008/4/21...

  15. Open wedge metatarsal osteotomy versus crescentic osteotomy to correct severe hallux valgus deformity - A prospective comparative study.

    Science.gov (United States)

    Wester, Jens Ulrik; Hamborg-Petersen, Ellen; Herold, Niels; Hansen, Palle Bo; Froekjaer, Johnny

    2016-03-01

    Different techniques of proximal osteotomies have been introduced to correct severe hallux valgus. The open wedge osteotomy is a newly introduced method for proximal osteotomy. The aim of this prospective randomized study was to compare the radiological and clinical results after operation for severe hallux valgus, comparing the open wedge osteotomy to the crescentic osteotomy which is our traditional treatment. Forty-five patients with severe hallux valgus (hallux valgus angle >35̊, and intermetatarsal angle >15̊) were included in this study. The treatment was proximal open wedge osteotomy and fixation with plate (Hemax), group 1, or operation with proximal crescentic osteotomy and fixation with a 3mm cannulated screw, group 2. The mean age was 52 years (19-71). Forty-one females and four males were included. Clinical and radiological follow-ups were performed 4 and 12 months after the operation. In group 1 the hallux valgus angle decreased from 39.0̊ to 24.1̊ after 4 months and 27.9̊ after 12 months. In group 2 the angle decreased from 38.3̊ to 21.4̊ after 4 months and 27.0̊ after 12 months. The intermetatarsal angle in group 1 was 19.0̊ preoperatively, 11.6̊ after 4 months and 12.6̊ after 12 months. In group 2 the mean intermetatarsal angle was 18.9̊ preoperatively, 12.0̊ after 4 months and 12.6̊ after 12 months. The AOFAS score improved from 59.3 to 81.5 in group 1 and from 61.8 to 84.8 in group 2 respectively measured 12 months postoperatively. The relative length of the 1 metatarsal compared to 2 metatarsal bone was 0.88 and 0.87 preoperatively and 0.88 and 0.86 for group 1 and 2 respectively measured after 12 months. Crescentic osteotomy and open wedge osteotomy improve AOFAS score and VAS scores on patients operated with severe hallux valgus. No significant difference was found in the two groups looking at the postoperative improvement of HVA and IMA measured 4 and 12 months postoperatively. The postoperative VAS score and AOFAS score were

  16. Neglected surgically intervened bilateral congenital dislocation of knee in an adolescent

    Directory of Open Access Journals (Sweden)

    Jaswant Kumar

    2014-01-01

    Full Text Available Neglected bilateral congenital dislocation of knee is unusual. A 12 year old boy presented with inability to walk due to buckling of the knee. The symptoms were present since the child learnt walking. He preferred not to walk. Bilateral supracondylar femoral osteotomy was done at the age of 6 years. Patient had a fixed flexion deformity of both knees, 30° in the right (range of flexion from 30° to 45° and 45° fixed flexion deformity in left knee respectively (range of flexion from 45° to 65° when presented to us. The radiological examination revealed bilateral congenital dislocation of knee (CDK. No syndromic association was observed. He was planned for staged treatment. In stage I, the knee joints were distracted by Ilizarov ring fixators and this was followed by open reduction of both the knee joints in stage II. A bilateral supracondylar extension osteotomy was done 18 months after the previous surgery (stage III. The final followup visit at 4 years the patient presented with range of motion 5-100° and 5-80° on the right and left knee respectively with good functional outcome. The case is reported in view of lack of treatment guidelines for long standing neglected CDK in an adolescent child.

  17. The Average Change in Facial Height Following Bilateral Sagittal Split Osteotomy Advancement in Class II Patients

    Science.gov (United States)

    2017-04-21

    internship and residency programs. 3. Please know that if you are a Graduate Health Sciences Education student and your department has told you they... source for your study [ e .g., S9 MOW CRD Graduate Health Sciences Education (GHSE) (SGS O&M); SGS R&D; Tri-Service Nursing Research Program (TSNRP...a legal ethics review to address any potential conflicts related to DoD personnel participating in non-DoD sponsored conferences, professional

  18. A Comparison between External versus Internal Lateral Osteotomy in Rhinoplasty

    Directory of Open Access Journals (Sweden)

    M Hashemi

    2005-01-01

    Full Text Available Background: Lateral osteotomy is a major part of rhinoplasty for remodeling external facet of the nose and narrowing of nasal base and dorsum after removal of the hump. There are two techniques for lateral osteotomy known as external and internal. Each of these provide advantages and impose limitations. The purpose of our study was to compare the severity of postoperative edema and ecchymosis between internal and external osteotomy techniques. Methods: This study was designed as a clinical trial on 30 cases. With randomization, one side of the nasal bone was selected for internal approach, and the other side, for external approach. Then, on the 1st and 7th days after surgery, the patients were scored for the severity of edema and ecchymosis. Results: On the first day after surgery, not only edema, but also ecchymosis was lower with the external osteotomy than with the internal approach (P = 0.037, P = 0.002, respectively. The severity of ecchymosis, on the 7th postoperative day, was lower with the external approach, and the difference was significant (P = 0.011. The severity of both edema and ecchymosis on the first postoperative day was evaluated higher in females, with statistically significant differences (P = 0.05 for edema and P = 0.003 for ecchymosis. The extension of ecchymosis on the 7th postoperative day was higher in women (P = 0.05. There were no significant differences between the two approaches in medialization of the involved bones and no apparent asymmetries either. Conclusion: According to the results of this study, external osteotomy seems to be the approach of choice, provided that the surgeon has enough experience in doing it. Keywords: Rhinoplasty, Internal osteotomy, External osteotomy, Ecchymosis, Edema

  19. Queen Mary Two Step

    OpenAIRE

    Melin, Mats H.

    2007-01-01

    n/a Dance devised by Mats Melin in October 2007 whilst teaching Ceilidh dancing on board the cruise ship Queen Mary 2 crossing the Atlantic from Southampton to New York and back with the Ian Muir Sound from Prestwick. The segment of music featured is from Ian Muir Scottish Dance Band's recording of an Eva Three step.

  20. Two Steps Back

    Science.gov (United States)

    Dicketts, Sally; Landman, Robin

    2011-01-01

    During a recent episode of Radio 4's Desert Island Discs, Kirsty Young's guest--one of Britain's most influential women--explained how a further education teacher had changed her life. Heather Rabbatts, who was born in Jamaica and moved to England, found school difficult. She was "picked on for being mixed-race," failed her 11-plus and…

  1. Using a two-step method to measure transgender identity in Latin America/the Caribbean, Portugal, and Spain.

    Science.gov (United States)

    Reisner, Sari L; Biello, Katie; Rosenberger, Joshua G; Austin, S Bryn; Haneuse, Sebastien; Perez-Brumer, Amaya; Novak, David S; Mimiaga, Matthew J

    2014-11-01

    Few comparative data are available internationally to examine health differences by transgender identity. A barrier to monitoring the health and well-being of transgender people is the lack of inclusion of measures to assess natal sex/gender identity status in surveys. Data were from a cross-sectional anonymous online survey of members (n > 36,000) of a sexual networking website targeting men who have sex with men in Spanish- and Portuguese-speaking countries/territories in Latin America/the Caribbean, Portugal, and Spain. Natal sex/gender identity status was assessed using a two-step method (Step 1: assigned birth sex, Step 2: current gender identity). Male-to-female (MTF) and female-to-male (FTM) participants were compared to non-transgender males in age-adjusted regression models on socioeconomic status (SES) (education, income, sex work), masculine gender conformity, psychological health and well-being (lifetime suicidality, past-week depressive distress, positive self-worth, general self-rated health, gender related stressors), and sexual health (HIV-infection, past-year STIs, past-3 month unprotected anal or vaginal sex). The two-step method identified 190 transgender participants (0.54%; 158 MTF, 32 FTM). Of the 12 health-related variables, six showed significant differences between the three groups: SES, masculine gender conformity, lifetime suicidality, depressive distress, positive self-worth, and past-year genital herpes. A two-step approach is recommended for health surveillance efforts to assess natal sex/gender identity status. Cognitive testing to formally validate assigned birth sex and current gender identity survey items in Spanish and Portuguese is encouraged.

  2. Effects of Sputtering Parameters on AlN Film Growth on Flexible Hastelloy Tapes by Two-Step Deposition Technique.

    Science.gov (United States)

    Peng, Bin; Gong, Dongdong; Zhang, Wanli; Jiang, Jianying; Shu, Lin; Zhang, Yahui

    2016-08-10

    AlN thin films were deposited on flexible Hastelloy tapes and Si (100) substrate by middle-frequency magnetron sputtering. A layer of Y₂O₃ films was used as a buffer layer for the Hastelloy tapes. A two-step deposition technique was used to prepare the AlN films. The effects of deposition parameters such as sputtering power, N₂/Ar flow rate and sputtering pressure on the microstructure of the AlN thin films were systematically investigated. The results show that the dependency of the full width at half maximum (FWHM) of AlN/Y₂O₃/Hastelloy on the sputtering parameters is similar to that of AlN/Si (100). The FWHM of the AlN (002) peak of the prepared AlN films decreases with increasing sputtering power. The FWHM decreases with the increase of the N₂/Ar flow rate or sputtering pressure, and increases with the further increase of the N₂/Ar flow rate or sputtering pressure. The FWHM of the AlN/Y₂O₃/Hastelloy prepared under optimized parameters is only 3.7° and its root mean square (RMS) roughness is 5.46 nm. Based on the experimental results, the growth mechanism of AlN thin films prepared by the two-step deposition process was explored. This work would assist us in understanding the AlN film's growth mechanism of the two-step deposition process, preparing highly c-axis-oriented AlN films on flexible metal tapes and developing flexible surface acoustic wave (SAW) sensors from an application perspective.

  3. A Two-Step Approach for Analysis of Nonignorable Missing Outcomes in Longitudinal Regression: an Application to Upstate KIDS Study.

    Science.gov (United States)

    Liu, Danping; Yeung, Edwina H; McLain, Alexander C; Xie, Yunlong; Buck Louis, Germaine M; Sundaram, Rajeshwari

    2017-09-01

    Imperfect follow-up in longitudinal studies commonly leads to missing outcome data that can potentially bias the inference when the missingness is nonignorable; that is, the propensity of missingness depends on missing values in the data. In the Upstate KIDS Study, we seek to determine if the missingness of child development outcomes is nonignorable, and how a simple model assuming ignorable missingness would compare with more complicated models for a nonignorable mechanism. To correct for nonignorable missingness, the shared random effects model (SREM) jointly models the outcome and the missing mechanism. However, the computational complexity and lack of software packages has limited its practical applications. This paper proposes a novel two-step approach to handle nonignorable missing outcomes in generalized linear mixed models. We first analyse the missing mechanism with a generalized linear mixed model and predict values of the random effects; then, the outcome model is fitted adjusting for the predicted random effects to account for heterogeneity in the missingness propensity. Extensive simulation studies suggest that the proposed method is a reliable approximation to SREM, with a much faster computation. The nonignorability of missing data in the Upstate KIDS Study is estimated to be mild to moderate, and the analyses using the two-step approach or SREM are similar to the model assuming ignorable missingness. The two-step approach is a computationally straightforward method that can be conducted as sensitivity analyses in longitudinal studies to examine violations to the ignorable missingness assumption and the implications relative to health outcomes. © 2017 John Wiley & Sons Ltd.

  4. Establishment and validation of a two-step screening scheme for improved performance of serological screening of nasopharyngeal carcinoma.

    Science.gov (United States)

    Li, Tingdong; Guo, Xiaoyi; Ji, Mingfang; Li, Fugui; Wang, Han; Cheng, Weimin; Chen, Honglin; Ng, Munhon; Ge, Shengxiang; Yuan, Yong; Xia, Ningshao

    2018-02-25

    Nasopharyngeal carcinoma (NPC), which is closely associated with Epstein-Barr virus (EBV), is one of the most prevalent cancers in southeast China. Most NPC patients are diagnosed at late stage due to inconspicuous symptoms at the early stage, and the prognosis of these patients is poor. The early diagnosis rate of NPC could be significantly increased by serological screening, but the positive predictive value (PPV) is relatively low. A simple two-step serological screening scheme was established to improve the PPV of the screening strategy and was validated by a prospective cohort. Serum antibodies specific for EBNA1, Zta, Thymidine Kinase (TK), EAD, EAR, and VCA were detected by enzyme-linked immunosorbent assay. The combination of EBNA1/IgA and VCA/IgA was used in the first step of screening, and anti-early antigens (EAs) were used in the second step of screening. EAD/IgA was the most prominent marker in the second step of screening, and other anti-EAs were complementary to EAD/IgA. As validated by a prospective cohort including 4200 participants, using the combination of EAD/IgA and TK/IgA in the second step decreased the number of high-risk participants from 128 to 27, and increased the PPV from 4.69% to 18.52%, with only one very early-stage case missed. The two-step screening scheme provides a standardized approach for NPC screening with an improved PPV and may be used in future field studies. With this two-step serological screening method, more people benefit from the screening program without increasing the need for fiberoptic endoscopy. © 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  5. Using a Two-Step Method to Measure Transgender Identity in Latin America/the Caribbean, Portugal, and Spain

    Science.gov (United States)

    Reisner, Sari L.; Biello, Katie; Rosenberger, Joshua G.; Austin, S. Bryn; Haneuse, Sebastien; Perez-Brumer, Amaya; Novak, David S.; Mimiaga, Matthew J.

    2014-01-01

    Few comparative data are available internationally to examine health differences by transgender identity. A barrier to monitoring the health and well-being of transgender people is the lack of inclusion of measures to assess natal sex/gender identity status in surveys. Data were from a cross-sectional anonymous online survey of members (n > 36,000) of a sexual networking website targeting men who have sex with men in Spanish- and Portuguese-speaking countries/ territories in Latin America/the Caribbean, Portugal, and Spain. Natal sex/gender identity status was assessed using a two-step method (Step 1: assigned birth sex, Step 2: current gender identity). Male-to-female (MTF) and female-to-male (FTM) participants were compared to non-transgender males in age-adjusted regression models on socioeconomic status (SES) (education, income, sex work), masculine gender conformity, psychological health and well-being (lifetime suicidality, past-week depressive distress, positive self-worth, general self-rated health, gender related stressors), and sexual health (HIV-infection, past-year STIs, past-3 month unprotected anal or vaginal sex). The two-step method identified 190 transgender participants (0.54%; 158 MTF, 32 FTM). Of the 12 health-related variables, six showed significant differences between the three groups: SES, masculine gender conformity, lifetime suicidality, depressive distress, positive self-worth, and past-year genital herpes. A two-step approach is recommended for health surveillance efforts to assess natal sex/gender identity status. Cognitive testing to formally validate assigned birth sex and current gender identity survey items in Spanish and Portuguese is encouraged. PMID:25030120

  6. [The value of spleen sub-pedicle two steps severance with LigaSure in laparoscopic splenectomy].

    Science.gov (United States)

    Wang, Guang-yi; Liu, Ya-hui; Lü, Guo-yue; Liu, Kai; Zhang, Wei; Li, Nan; Tan, Yu-quan

    2008-10-01

    To evaluate the safety and utility of the methods of spleen sub-pedicle two steps severance with LigaSure Vessel Sealing System combined with ultrasound scalpel to resect peri-splenic ligaments during laparoscopic splenectomy. The methods and the curative effect of 32 patients with laparoscopic splenectomy performed by the way as mentioned above were summarized and analyzed. 4 males, 28 females, median 36 years (range 16 - 64 years). Mean dimensions of spleens were 17 cm (range 11 - 23 cm). Nineteen patients had idiopathic thrombocytopenia purpura (ITP), 6 hereditary spherocytosis (HS) (5 of them were the same family constellation), 3 hemolytic anemia (HA), 2 spleen injury with haematoma infection, 1 Evan syndrome, 1 leukemia. Peri-splenic ligaments were resected by LigaSure combined with ultrasound scalpel, splenic pedicle was resected by spleen sub-pedicle two steps severance with LigaSure when splenic pedicle were sufficiently free. Splenic pedicle was non-excisional occluded by LigaSure at pancreatic cauda, in the first step and was occluded and resected alongside of the spleen in the second step. All of the 32 cases were completely succeed, the average operating time was 70 min (55 - 130 min), the estimated intraoperative blood loss was 200 ml (50 - 600 ml), no complications such as abdominal haemorrhage, visceral injury, pancreatic leakage and infection were observed. All the patients were healed well, the average hospital stay after an operation was 6 days. The average expense of each patients could save 8050 yuan because Endo-GIA was not used. Spleen sub-pedicle two steps severance with LigaSure Vessel Sealing System combined with ultrasound scalpel to resect peri-splenic ligaments during laparoscopic splenectomy, which shorten the operating persistence time with less hemorrhage is a safe, effective and low-cost minimally invasive surgery in selective cases.

  7. Enzymatic saccharification of cellulose and cellulosic biomass of sweet potato (Ipomoea batatas L. ): two-step hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Tolbert, M.E.M.; Bhattacharya, S.; Biswas, P.K.

    1986-01-01

    The enzymatic hydrolysis of lignocellulosic biomass of sweet potato vines as well as microcrystalline cellulose, Sigmacell type 20, by cellulases from Trichoderma viride is reported. Material was treated with a concentrated solution of ZnCl2 and 0.5% hydrochloric acid and heated at 145C for 12 minutes. Hydrolysis of the cellulose precipitated by acetone was 2-2.5 times greater than untreated lignocellulose and approached 64% conversion. A two-step hydrolysis of treated or untreated cellulose resulted in higher conversion of cellulose into reducing sugars. Increasing cellulase concentrations increased the conversion, but an increase in substrate concentration resulted in a decrease in cellulose conversion. 20 references.

  8. Synthesis of Highly Dispersed and Highly Stable Supported Au–Pt Bimetallic Catalysts by a Two-Step Method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaofeng; Zhao, Haiyan; Wu, Tianpin; Liu, Yuzi; Liang, Xinhua

    2016-11-01

    Highly dispersed and highly stable supported bimetallic catalysts were prepared using a two-step process. Pt nanoparticles (NPs) were first deposited on porous γ-Al2O3 particles by atomic layer deposition (ALD). Au NPs were synthesized by using gold(III) chloride as the Au precursor, and then immobilized on ALD Pt/γ-Al2O3 particles. The Au–Pt bimetallic catalysts were highly active and highly stable in a vigorously stirred liquid phase reaction of glucose oxidation.

  9. Synthesis of cubic yttrium aluminum garnet (YAG) powders by co-precipitation and two-step calcinations

    Science.gov (United States)

    Girish, H. N.; Zhu, C.; Ma, F. F.; Shao, G. Q.

    2017-04-01

    YAG powders were synthesized by co-precipitation and two-step moderate calcinations at 600/800 °C or 600/900 °C in air, respectively. Two kinds of the synthesized powders both possess pure cubic YAG phases without any secondary phases such as YAH, YAP and YAM, etc.. The former has low agglomeration with nano-sized primary particles and large active energy, and the latter has homogeneously dispersed and well-crystallized particles, with a narrow particle size distribution of 8 - 13 µm.

  10. Low-temperature wafer direct bonding of silicon and quartz glass by a two-step wet chemical surface cleaning

    Science.gov (United States)

    Wang, Chenxi; Xu, Jikai; Zeng, Xiaorun; Tian, Yanhong; Wang, Chunqing; Suga, Tadatomo

    2018-02-01

    We demonstrate a facile bonding process for combining silicon and quartz glass wafers by a two-step wet chemical surface cleaning. After a post-annealing at 200 °C, strong bonding interfaces with no defects or microcracks were obtained. On the basis of the detailed surface and bonding interface characterizations, the bonding mechanism was explored and discussed. The amino groups terminated on the cleaned surfaces might contribute to the bonding strength enhancement during the annealing. This cost-effective bonding process has great potentials for silicon- and glass-based heterogeneous integrations without requiring a vacuum system.

  11. Reconstructing Genetic Regulatory Networks Using Two-Step Algorithms with the Differential Equation Models of Neural Networks.

    Science.gov (United States)

    Chen, Chi-Kan

    2017-07-26

    The identification of genetic regulatory networks (GRNs) provides insights into complex cellular processes. A class of recurrent neural networks (RNNs) captures the dynamics of GRN. Algorithms combining the RNN and machine learning schemes were proposed to reconstruct small-scale GRNs using gene expression time series. We present new GRN reconstruction methods with neural networks. The RNN is extended to a class of recurrent multilayer perceptrons (RMLPs) with latent nodes. Our methods contain two steps: the edge rank assignment step and the network construction step. The former assigns ranks to all possible edges by a recursive procedure based on the estimated weights of wires of RNN/RMLP (RE RNN /RE RMLP ), and the latter constructs a network consisting of top-ranked edges under which the optimized RNN simulates the gene expression time series. The particle swarm optimization (PSO) is applied to optimize the parameters of RNNs and RMLPs in a two-step algorithm. The proposed RE RNN -RNN and RE RMLP -RNN algorithms are tested on synthetic and experimental gene expression time series of small GRNs of about 10 genes. The experimental time series are from the studies of yeast cell cycle regulated genes and E. coli DNA repair genes. The unstable estimation of RNN using experimental time series having limited data points can lead to fairly arbitrary predicted GRNs. Our methods incorporate RNN and RMLP into a two-step structure learning procedure. Results show that the RE RMLP using the RMLP with a suitable number of latent nodes to reduce the parameter dimension often result in more accurate edge ranks than the RE RNN using the regularized RNN on short simulated time series. Combining by a weighted majority voting rule the networks derived by the RE RMLP -RNN using different numbers of latent nodes in step one to infer the GRN, the method performs consistently and outperforms published algorithms for GRN reconstruction on most benchmark time series. The framework of two-step

  12. First results on photon strength functions of 78Se from the two-step γ Cascades measurement

    Science.gov (United States)

    Valenta, Stanislav; Bečvář, František; Krtička, Milan; Tomandl, Ivo

    2017-09-01

    Two-step gamma cascades (TSCs) following the radiative capture of thermal neutrons in 77Se were measured at the research reactor at Řež near Prague. Results on photon strength functions (PSFs) of 78Se, obtained from comparison of experimental TSC spectra with outcomes of simulations under different assumptions about level density and PSFs using the DICEBOX algorithm, are presented. The main attention is paid to possible manifestation of the pygmy resonance observed recently in this nucleus in the nuclear resonance fluorescence measurement and low-energy PSF enhancement observed in Oslo-type experiments for all A ≲ 100 nuclei.

  13. A two-step approach to estimating selectivity and fishing power of research gill nets used in Greenland waters

    DEFF Research Database (Denmark)

    Hovgård, Holger

    1996-01-01

    Catches of Atlantic cod (Gadus morhua) from Greenland gill-net surveys were analyzed by a two-step approach. In the initial step the form of the selection curve was identified as binormal, which was caused by fish being gilled or caught by the maxillae. Both capture processes could be described...... by normal distributions and could be related to mesh size in accordance with the principle of geometrical similarity. In the second step the selection parameters were estimated by a nonlinear least squares fit. The model also estimated the relative efficiency of the two capture processes and the fishing...

  14. Effect of a locking triple pelvic osteotomy plate on screw loosening in 26 dogs.

    Science.gov (United States)

    Rose, Scott A; Peck, Jeffrey N; Tano, Cheryl A; Uddin, Nizam; de Haan, Jacek J

    2012-01-01

    To evaluate the complication rate of the double (DPO) and triple pelvic osteotomy (TPO) procedure (unilateral and bilateral) with a locking purpose-specific plate. Retrospective case series Dogs (n = 26; 38 hips) Medical records (January 2007-January 2011) of dogs that had unilateral or bilateral DPO or TPO were evaluated. Signalment, age, body weight, estimated preoperative subluxation and reduction angles, lameness, and complications were evaluated. Follow-up radiographs were evaluated for implant loosening or failure, femoral head coverage (FCH), pelvic dimensions, and radiographic evidence of healing. Screw loosening occurred in 1 of 266 (0.4%) screws placed and in 1 of 38 hips (2.6%). The rate of screw loosening was significantly lower than previously reported. Only 1 hip (2.6%) developed a major complication. Minor complications involving implants occurred in 2 hips (5.3%). Three to 5 locking screws were used per plate. There was a significant increase in FCH and Norberg angle (NA) compared with preoperative values. No clinically significant change in pelvic canal dimensions measured at 3 locations was identified. Locking 7-hole TPO plates with 3-5 locking screws resulted in a lower rate of major and minor implant associated complications than the reported complication rate for conventional 6-hole plates. En bloc pullout of the caudal aspect of the plate is an infrequent but repeatable complication associated with the locking TPO implant. © Copyright 2011 by The American College of Veterinary Surgeons.

  15. First Metatarsal Proximal Opening Wedge Osteotomy for Correction of Hallux Valgus Deformity: Comparison of Straight versus Oblique Osteotomy

    Science.gov (United States)

    Han, Seung Hwan; Park, Eui Hyun; Jo, Joon; Koh, Yong Gon; Lee, Jin Woo; Choi, Woo Jin

    2015-01-01

    Purpose The aim of this study was to compare clinical and radiographic outcomes of proximal opening wedge osteotomy using a straight versus oblique osteotomy. Materials and Methods We retrospectively reviewed 104 consecutive first metatarsal proximal opening wedge osteotomies performed in 95 patients with hallux valgus deformity. Twenty-six feet were treated using straight metatarsal osteotomy (group A), whereas 78 feet were treated using oblique metatarsal osteotomy (group B). The hallux valgus angle (HVA), intermetatarsal angle (IMA), distal metatarsal articular angle, and distance from the first to the second metatarsal (distance) were measured for radiographic evaluation, whereas the American Orthopaedic Foot and Ankle Society (AOFAS) forefoot score was used for clinical evaluation. Results Significant corrections in the HVA, IMA, and distance from the first to the second metatarsal were obtained in both groups at the last follow-up (p<0.001). There was no difference in the mean IMA correction between the 2 groups (6.1±2.7° in group A and 6.0±2.1° in group B). However, a greater correction in the HVA and distance from the first to the second metatarsal were found in group B (HVA, 13.2±8.2°; distance, 25.1±0.2 mm) compared to group A (HVA, 20.9±7.7°; distance, 28.1±0.3 mm; p<0.001). AOFAS scores were improved in both groups. However, group B demonstrated a greater improvement relative to group A (p=0.005). Conclusion Compared with a straight first metatarsal osteotomy, an oblique first metatarsal osteotomy yielded better clinical and radiological outcomes. PMID:25837181

  16. Modified Mitchell osteotomy alone does not have higher rate of residual metatarsalgia than combined first and lesser metatarsal osteotomy

    Directory of Open Access Journals (Sweden)

    Shu-Jung Chen

    2015-04-01

    Full Text Available Transfer metatarsalgia (TM is a common forefoot disorder secondary to hallux valgus (HV. Some authors suggest that a combined lesser metatarsal osteotomy while undergoing HV surgery improves metatarsalgia, whereas others concluded that isolated HV corrective osteotomy can improve symptomatic metatarsalgia. The main purpose of this retrospective study was to compare clinical outcomes in patients with and without combined lesser metatarsal osteotomy while receiving HV correction surgery. We retrospectively reviewed the patients who underwent osteotomy for HV correction between January 2000 and December 2010. All patients underwent HV correction with modified Mitchell osteotomy. Clinical evaluations including the American Orthopaedic Foot and Ankle Society score and residual metatarsalgia were assessed, and radiographic measurements were carried out. Sixty-five patients (83 feet meeting the selection criteria were enrolled. Thirty feet receiving a combined lesser metatarsal osteotomy were classified as the combined surgery (CS group, and the others were classified as the control (CN group (53 feet. The overall rate of persistent symptomatic metatarsalgia was 19.28% after operative treatment. There were six feet with residual metatarsalgia in the CS group, and 10 feet in the CN group. There was no significant difference in the rate of persistent symptoms between the two groups (p = 0.9. According to this result, modified Mitchell osteotomy alone did not have a higher rate of residual metatarsalgia than CS. We also found that the average recovery rate of TM was about 80.7% and those patients whose preoperative HV angle was > 30° had the higher risk of residual metatarsalgia after surgery.

  17. Bilateral simultaneous infective keratitis.

    Science.gov (United States)

    On Annie, Lai Hiu; Ray, Manotosh

    2017-08-01

    To analyze the demographics, risk factors, clinical and microbiological characteristics of cases of bilateral simultaneous infective keratitis. In this retrospective case series, patients with clinical evidence of bilateral simultaneous infective keratitis were identified from January 1, 2011 to August 31, 2016. Demographics, risk factors, clinical and microbiological characteristics, and treatment outcomes were analyzed. Five patients (ten eyes) with bilateral simultaneous infective keratitis were identified. The mean age was 32.8 years (SD,±8.8; range, 24-44). All the patients were disposable soft contact lens wearers before presentation. The average size of the infiltrate was 4.76mm 2 (SD±9.0; range, 0.2-31.34). A total of 4 types of bacteria were isolated, with Pseudomonas aeruginosa being the most frequently isolated bacteria involving 5 eyes of four patients. Infection resolved with medical treatment in 9 eyes, 1 patient required therapeutic corneal transplantation for impending corneal perforation. The average time taken for infection to resolve was 6.7days (SD±4.5; range, 2-16). In this case series, the most common risk factor of bilateral simultaneous microbial keratitis was use of soft disposable contact lens and the most commonly isolated bacteria was Pseudomonas aeruginosa. Bilateral simultaneous infective keratitis is uncommon and is a serious complication of contact lens use in immunocompetent adult patients. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  18. [Distal femoral osteotomy using a lateral opening wedge technique].

    Science.gov (United States)

    Feucht, M J; Mehl, J; Forkel, P; Imhoff, A B; Hinterwimmer, S

    2017-08-01

    To shift the weight-bearing axis of the lower limb medially by opening a lateral-based metaphyseal osteotomy at the distal femur. Femoral-based valgus malalignment and symptomatic lateral unicompartimental osteoarthritis, lateral hyperpression syndrome, cartilage therapy of the lateral compartment, lateral meniscal replacement/transplantation, medial instability with valgus thrust, reconstruction of the medial collateral ligament, patellar instability and/or maltracking. Advanced cartilage damage (>grade 2) or subtotal meniscal loss of the medial compartment, age >65 years (relative), nicotine abuse, body mass index >30, flexion contracture >25°, corrections with a wedge base >10 mm in case of congenital deformities, inflammatory or septic arthritis, severe osteoporosis. Lateral approach to the distal femur; biplanar osteotomy (frontal + axial osteotomy), gradual opening of the osteotomy, osteotomy fixation with a locking plate. Free range of motion. Partial weight bearing with 20 kg for 2 weeks, followed by progressive weight bearing thereafter. Mean improvement of knee scores from 20-30 points and mean 10-year survival rate of 80% in patients with lateral unicompartimental osteoarthritis. Mean complication rate of 9%.

  19. A two-step acid-catalyzed process for the production of biodiesel from rice bran oil

    Energy Technology Data Exchange (ETDEWEB)

    Zullaikah, S.; Lai, Chao Chin; Vali, S.R.; Ju, Yi Hsu [National Taiwan Univ. of Science and Technology, Taipei (China). Dept. of Chemical Engineering

    2005-11-15

    A study was undertaken to examine the effect of temperature, moisture and storage time on the accumulation of free fatty acid in the rice bran. Rice bran stored at room temperature showed that most triacylglyceride was hydrolyzed and free fatty acid (FFA) content was raised up to 76% in six months. A two-step acid-catalyzed methanolysis process was employed for the efficient conversion of rice bran oil into fatty acid methyl ester (FAME). The first step was carried out at 60 {sup o}C. Depending on the initial FFA content of oil, 55-90% FAME content in the reaction product was obtained. More than 98% FFA and less than 35% of TG were reacted in 2 h. The organic phase of the first step reaction product was used as the substrate for a second acid-catalyzed methanolysis at 100 {sup o}C. By this two-step methanolysis reaction, more than 98% FAME in the product can be obtained in less than 8 h. Distillation of reaction product gave 99.8% FAME (biodiesel) with recovery of more than 96%. The residue contains enriched nutraceuticals such as {gamma}-oryzanol (16-18%), mixture of phytosterol, tocol and steryl ester (19-21%). (author)

  20. Two-step synthesis of fatty acid ethyl ester from soybean oil catalyzed by Yarrowia lipolytica lipase

    Directory of Open Access Journals (Sweden)

    Chen Jinnan

    2011-03-01

    Full Text Available Abstract Background Enzymatic biodiesel production by transesterification in solvent media has been investigated intensively, but glycerol, as a by-product, could block the immobilized enzyme and excess n-hexane, as a solution aid, would reduce the productivity of the enzyme. Esterification, a solvent-free and no-glycerol-release system for biodiesel production, has been developed, and two-step catalysis of soybean oil, hydrolysis followed by esterification, with Yarrowia lipolytica lipase is reported in this paper. Results First, soybean oil was hydrolyzed at 40°C by 100 U of lipase broth per 1 g of oil with approximately 30% to 60% (vol/vol water. The free fatty acid (FFA distilled from this hydrolysis mixture was used for the esterification of FFA to fatty acid ethyl ester by immobilized lipase. A mixture of 2.82 g of FFA and equimolar ethanol (addition in three steps were shaken at 30°C with 18 U of lipase per 1 gram of FFA. The degree of esterification reached 85% after 3 hours. The lipase membranes were taken out, dehydrated and subjected to fresh esterification so that over 82% of esterification was maintained, even though the esterification was repeated every 3 hours for 25 batches. Conclusion The two-step enzymatic process without glycerol released and solvent-free demonstrated higher efficiency and safety than enzymatic transesterification, which seems very promising for lipase-catalyzed, large-scale production of biodiesel, especially from high acid value waste oil.

  1. A Two-Step Process of Nitrous Oxide before Carbon Dioxide for Humanely Euthanizing Piglets: On-Farm Trials

    Directory of Open Access Journals (Sweden)

    Rebecca K. Smith

    2018-04-01

    Full Text Available Current methods of euthanizing piglets are raising animal welfare concerns. Our experiment used a novel two-step euthanasia method, using nitrous oxide (N2O for six minutes and then carbon dioxide (CO2 on compromised 0- to 7-day-old piglets. A commercial euthanasia chamber was modified to deliver two euthanasia treatments: the two-step method using N2O then CO2 (N2O treatment or only CO2 (CO2 treatment. In Experiment 1, 18 piglets were individually euthanized. In Experiment 2, 18 groups of four to six piglets were euthanized. In the N2O treatment, piglets lost posture, indicating the onset of losing consciousness, before going into CO2 where they showed heavy breathing and open-mouth breathing; whereas piglets in the CO2 treatment did not lose posture until after exhibiting these behaviors (p ≤ 0.004. However, piglets in the N2O treatment took longer to lose posture compared to the CO2 treatment (p < 0.001. Piglets in the N2O treatment displayed more behavioral signs of stress and aversion: squeals/minute (p = 0.004, escape attempts per pig (p = 0.021, and righting responses per pig (p = 0.084 in a group setting. In these regards, it cannot be concluded that euthanizing piglets for 6 min with N2O and then CO2 is more humane than euthanizing with CO2 alone.

  2. An Exceptionally Facile Two-Step Structural Isomerization and Detoxication via a Water-Assisted Double Lossen Rearrangement

    Science.gov (United States)

    Li, Feng; Huang, Chun-Hua; Xie, Lin-Na; Qu, Na; Shao, Jie; Shao, Bo; Zhu, Ben-Zhan

    2016-01-01

    N-hydroxyphthalimide (NHPI), which is best known as an organocatalyst for efficient C-H activation, has been found to be oxidized by quinoid compounds to its corresponding catalytically active nitroxide-radical. Here, we found that NHPI can be isomerized into isatoic anhydride by an unusually facile two-step method using tetrachloro-1,4-benzoquinone (TCBQ, p-chloranil), accompanied by a two-step hydrolytic dechlorination of highly toxic TCBQ into the much less toxic dihydroxylation product, 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid). Interestingly, through the complementary application of oxygen-18 isotope-labeling, HPLC combined with electrospray ionization quadrupole time-of-flight and high resolution Fourier transform ion cyclotron resonance mass spectrometric studies, we determined that water was the source and origin of oxygen for isatoic anhydride. Based on these data, we proposed that nucleophilic attack with a subsequent water-assisted Lossen rearrangement coupled with rapid intramolecular addition and cyclization in two consecutive steps was responsible for this unusual structural isomerization of NHPI and concurrent hydroxylation/detoxication of TCBQ. This is the first report of an exceptionally facile double-isomerization of NHPI via an unprecedented water-assisted double-Lossen rearrangement under normal physiological conditions. Our findings may have broad implications for future research on hydroxamic acids and polyhalogenated quinoid carcinogens, two important classes of compounds of major chemical and biological interest. PMID:28008985

  3. Two-Step Multi-Physics Analysis of an Annular Linear Induction Pump for Fission Power Systems

    Science.gov (United States)

    Geng, Steven M.; Reid, Terry V.

    2016-01-01

    One of the key technologies associated with fission power systems (FPS) is the annular linear induction pump (ALIP). ALIPs are used to circulate liquid-metal fluid for transporting thermal energy from the nuclear reactor to the power conversion device. ALIPs designed and built to date for FPS project applications have not performed up to expectations. A unique, two-step approach was taken toward the multi-physics examination of an ALIP using ANSYS Maxwell 3D and Fluent. This multi-physics approach was developed so that engineers could investigate design variations that might improve pump performance. Of interest was to determine if simple geometric modifications could be made to the ALIP components with the goal of increasing the Lorentz forces acting on the liquid-metal fluid, which in turn would increase pumping capacity. The multi-physics model first calculates the Lorentz forces acting on the liquid metal fluid in the ALIP annulus. These forces are then used in a computational fluid dynamics simulation as (a) internal boundary conditions and (b) source functions in the momentum equations within the Navier-Stokes equations. The end result of the two-step analysis is a predicted pump pressure rise that can be compared with experimental data.

  4. Sequential Coalescence Enabled Two-Step Microreactions in Triple-Core Double-Emulsion Droplets Triggered by an Electric Field.

    Science.gov (United States)

    Jia, Yankai; Ren, Yukun; Hou, Likai; Liu, Weiyu; Deng, Xiaokang; Jiang, Hongyuan

    2017-12-01

    Advances in microfluidic emulsification have enabled the generation of exquisite multiple-core droplets, which are promising structures to accommodate microreactions. An essential requirement for conducting reactions is the sequential coalescence of the multiple cores encapsulated within these droplets, therefore, mixing the reagents together in a controlled sequence. Here, a microfluidic approach is reported for the conduction of two-step microreactions by electrically fusing three cores inside double-emulsion droplets. Using a microcapillary glass device, monodisperse water-in-oil-in-water droplets are fabricated with three compartmented reagents encapsulated inside. An AC electric field is then applied through a polydimethylsiloxane chip to trigger the sequential mixing of the reagents, where the precise sequence is guaranteed by the discrepancy of the volume or conductivity of the inner cores. A two-step reaction in each droplet is ensured by two times of core coalescence, which totally takes 20-40 s depending on varying conditions. The optimal parameters of the AC signal for the sequential fusion of the inner droplets are identified. Moreover, the capability of this technique is demonstrated by conducting an enzyme-catalyzed reaction used for glucose detection with the double-emulsion droplets. This technique should benefit a wide range of applications that require multistep reactions in micrometer scale. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Model predictive control of two-step nitrification and its validation via short-cut nitrification tests.

    Science.gov (United States)

    Sui, Jun; Luo, Fan; Li, Jie

    2016-10-01

    Short-cut nitrification (SCN) is shown to be an attractive technology due to its savings in aeration and external carbon source addition cost. However, the shortage of excluding nitrite nitrogen as a model state in an Activated Sludge Model limits the model predictive control of biological nitrogen removal via SCN. In this paper, a two-step kinetic model was developed based on the introduction of pH and temperature as process controller, and it was implemented in an SBR reactor. The simulation results for optimizing operating conditions showed that with increasing of dissolved oxygen (DO) the rate of ammonia oxidation and nitrite accumulation firstly increased in order to achieve a SCN process. By further increasing DO, the SCN process can be transformed into a complete nitrification process. In addition, within a certain range, increasing sludge retention time and aeration time are beneficial to the accumulation of nitrite. The implementation results in the SBR reactor showed that the data predicted by the kinetic model are in agreement with the data obtained, which indicate that the two-step kinetic model is appropriate to simulate the ammonia removal and nitrite production kinetics.

  6. Biocatalyst including porous enzyme cluster composite immobilized by two-step crosslinking and its utilization as enzymatic biofuel cell

    Science.gov (United States)

    Chung, Yongjin; Christwardana, Marcelinus; Tannia, Daniel Chris; Kim, Ki Jae; Kwon, Yongchai

    2017-08-01

    An enzyme cluster composite (TPA/GOx) formed from glucose oxidase (GOx) and terephthalaldehyde (TPA) that is coated onto polyethyleneimine (PEI) and carbon nanotubes (CNTs) is suggested as a new catalyst ([(TPA/GOx)/PEI]/CNT). In this catalyst, TPA promotes inter-GOx links by crosslinking to form a large and porous structure, and the TPA/GOx composite is again crosslinked with PEI/CNT to increase the amount of immobilized GOx. Such a two-step crosslinking (i) increases electron transfer because of electron delocalization by π conjugation and (ii) reduces GOx denaturation because of the formation of strong chemical bonds while its porosity facilitates mass transfer. With these features, an enzymatic biofuel cell (EBC) employing the new catalyst is fabricated and induces an excellent maximum power density (1.62 ± 0.08 mW cm-2), while the catalytic activity of the [(TPA/GOx)/PEI]/CNT catalyst is outstanding. This is clear evidence that the two-step crosslinking and porous structure caused by adoption of the TPA/GOx composite affect the performance enhancement of EBC.

  7. 3D Catheter Shape Determination for Endovascular Navigation Using a Two-Step Particle Filter and Ultrasound Scanning.

    Science.gov (United States)

    Chen, Fang; Liu, Jia; Liao, Hongen

    2017-03-01

    In endovascular catheter interventions, the determination of the three-dimensional (3D) catheter shape can increase navigation information and help reduce trauma. This study describes a shape determination method for a flexible interventional catheter using ultrasound scanning and a two-step particle filter without X-ray fluoroscopy. First, we propose a multi-feature, multi-template particle filter algorithm for accurate catheter tracking from ultrasound images. Second, we model the mechanical behavior of the catheter and apply a particle filter shape optimization algorithm to refine the results from the first step. Finally, the acquired catheter's 3D shapes are displayed together with the preoperative 3D images of the cardiac structures to provide intuitive endovascular navigation. We validated our method using ultrasound scanning of the straight and curved catheters in a water tank, and the shape determination errors were 1.44 ± 0.38 mm and 1.95 ± 0.46 mm, respectively. Further, endovascular catheter shape determination was validated in a catheter intervention experiment with a heart phantom. The error of the acquired endovascular catheter shape was 2.23 ± 0.87 mm. These results demonstrate that our two-step method is both accurate and effective. Using ultrasound scanning for shape determination of a flexible catheter will be helpful in endovascular interventions, reducing exposure to radiation and providing rich navigation information.

  8. The role of MDP in a bonding resin of a two-step self-etching adhesive system.

    Science.gov (United States)

    Matsui, Naoko; Takagaki, Tomohiro; Sadr, Alireza; Ikeda, Masaomi; Ichinose, Shizuko; Nikaido, Toru; Tagami, Junji

    2015-01-01

    The purpose of this study was to evaluate the role of 10-methacryloyloxydecyl dihydrogen phosphate (MDP) contained in the bonding resin of a two-step self-etch adhesive system. An experimental adhesive (M0) containing MDP only in the primer, but not in the bonding resin was prepared. Clearfil SE Bond (MM) and M0 were compared in terms of microtensile bond strength to dentin, ultimate tensile strength of the bonding resin, and dentin-resin bonding interface morphology under SEM and TEM. The immediate µTBS values of MM significantly decreased after thermal cycles while M0 were stable even after 10,000 cycles. In the SEM observations, formation of erosion was observed beneath the acid-base resistant zone only in M0. The results suggested that MDP in the bonding resin of the two-step self-etching system; 1) improved the immediate bond strength, but caused reduction in long-term bond durability; 2) offered the advantages of acid-base resistance at the ABRZ forefront area.

  9. Two Step Procedure Using a 1-D Slab Spectral Geometry in a Pebble Bed Reactor Core Analysis

    International Nuclear Information System (INIS)

    Lee, Hyun Chul; Kim, Kang Seog; Noh, Jae Man; Joo, Hyung Kook

    2005-01-01

    A strong spectral interaction between the core and the reflector has been one of the main concerns in the analysis of pebble bed reactor cores. To resolve this problem, VSOP adopted iteration between the spectrum calculation in a spectral zone and the global core calculation. In VSOP, the whole problem domain is divided into many spectral zones in which the fine group spectrum is calculated using bucklings for fast groups and albedos for thermal groups from the global core calculation. The resulting spectrum in each spectral zone is used to generate broad group cross sections of the spectral zone for the global core calculation. In this paper, we demonstrate a two step procedure in a pebble bed reactor core analysis. In the first step, we generate equivalent cross sections from a 1-D slab spectral geometry model with the help of the equivalence theory. The equivalent cross sections generated in this way include the effect of the spectral interaction between the core and the reflector. In the second step, we perform a diffusion calculation using the equivalent cross sections generated in the first step. A simple benchmark problem derived from the PMBR-400 Reactor was introduced to verify this approach. We compared the two step solutions with the Monte Carlo (MC) solutions for the problem

  10. Lateral stability of the spring-mass hopper suggests a two-step control strategy for running.

    Science.gov (United States)

    Carver, Sean G; Cowan, Noah J; Guckenheimer, John M

    2009-06-01

    This paper investigates the control of running gaits in the context of a spring loaded inverted pendulum model in three dimensions. Specifically, it determines the minimal number of steps required for an animal to recover from a perturbation to a specified gait. The model has four control inputs per step: two touchdown angles (azimuth and elevation) and two spring constants (compression and decompression). By representing the locomotor movement as a discrete-time return map and using the implicit function theorem we show that the number of recovery steps needed following a perturbation depends upon the goals of the control mechanism. When the goal is to follow a straight line, two steps are necessary and sufficient for small lateral perturbations. Multistep control laws have a larger number of control inputs than outputs, so solutions of the control problem are not unique. Additional constraints, referred to here as synergies, are imposed to determine unique control inputs for perturbations. For some choices of synergies, two-step control can be expressed as two iterations of its first step policy and designed so that recovery occurs in just one step for all perturbations for which one-step recovery is possible.

  11. A Dynamic Range Enhanced Readout Technique with a Two-Step TDC for High Speed Linear CMOS Image Sensors

    Directory of Open Access Journals (Sweden)

    Zhiyuan Gao

    2015-11-01

    Full Text Available This paper presents a dynamic range (DR enhanced readout technique with a two-step time-to-digital converter (TDC for high speed linear CMOS image sensors. A multi-capacitor and self-regulated capacitive trans-impedance amplifier (CTIA structure is employed to extend the dynamic range. The gain of the CTIA is auto adjusted by switching different capacitors to the integration node asynchronously according to the output voltage. A column-parallel ADC based on a two-step TDC is utilized to improve the conversion rate. The conversion is divided into coarse phase and fine phase. An error calibration scheme is also proposed to correct quantization errors caused by propagation delay skew within −Tclk~+Tclk. A linear CMOS image sensor pixel array is designed in the 0.13 μm CMOS process to verify this DR-enhanced high speed readout technique. The post simulation results indicate that the dynamic range of readout circuit is 99.02 dB and the ADC achieves 60.22 dB SNDR and 9.71 bit ENOB at a conversion rate of 2 MS/s after calibration, with 14.04 dB and 2.4 bit improvement, compared with SNDR and ENOB of that without calibration.

  12. Use of a two-step ultrafiltration procedure to concentrate viral hemorrhagic septicemia virus (VHSV) in seawater.

    Science.gov (United States)

    Kim, Soo-Jin; Kim, Jong-Oh; Kim, Wi-Sik; Oh, Myung-Joo

    2015-11-01

    Viral hemorrhagic septicemia virus (VHSV) has been reported to be stable in both fresh as well as seawater, suggesting that VHSV exists in natural aquatic environments and might have an effect on the wild and cultured fish. However, VHSV is below the detectable limits of laboratory tests in natural seawater. In this study, a two-step ultrafiltration (UF) procedure was used to concentration of VHSV in seawater, providing samples that were tested for infectivity by cell culture and the presence of VHSV by quantitative reverse transcriptase PCR (qRT-PCR) methods. Overall, VHSV was approximately concentrated 100-1000 times in 1, 5 and 10 L, seawater volumes respectively: from 2.81×10(6) to 6.53×10(7)/mL and 10(3.3) to 10(3.8)TCID50/mL prior to the UF procedure, to 3.78×10(8), 1.16 × 10(11), and 9.12 × 10(10)/mL after the procedure. This is the first report of concentrating VHSV using an UF method that was specifically designed for seawater samples. In addition, the two-step UF procedure appears to be compatible with viral cell culture and qRT-PCR methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method

    International Nuclear Information System (INIS)

    Wu, Xiaoguang; Zhao, Xu; Li, Yi; Yang, Tao; Yan, Xiujuan; Wang, Ke

    2015-01-01

    In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO 3 layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO 3 layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO 3 coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). - Graphical abstract: FESEM images of enamel slices etched for 60 s and repaired by the two-step method with Glu concentration of 20.00 mmol/L. (A) The boundary (dotted line) of the repaired areas (b) and unrepaired areas (a). (Some selected areas of etched enamel slices were coated with a nail polish before the reaction, which was removed by acetone after the reaction); (B) high magnification image of Ga, (C) high magnification image of Gb. In situ fabrication of carbonated

  14. In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xiaoguang [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China); Zhao, Xu [College of Chemistry, Jilin University, Changchun 130021 (China); Li, Yi, E-mail: lyi99@jlu.edu.cn [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China); Yang, Tao [Department of Stomatology, Children' s Hospital of Changchun, 130051 (China); Yan, Xiujuan; Wang, Ke [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China)

    2015-09-01

    In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO{sub 3} layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO{sub 3} layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO{sub 3} coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). - Graphical abstract: FESEM images of enamel slices etched for 60 s and repaired by the two-step method with Glu concentration of 20.00 mmol/L. (A) The boundary (dotted line) of the repaired areas (b) and unrepaired areas (a). (Some selected areas of etched enamel slices were coated with a nail polish before the reaction, which was removed by acetone after the reaction); (B) high magnification image of Ga, (C) high magnification image of Gb. In situ fabrication of

  15. Open Wedge High Tibial Osteotomy with Distal Tubercle Osteotomy Lessens Change in Patellar Position

    Directory of Open Access Journals (Sweden)

    Hoon Park

    2017-01-01

    Full Text Available The purpose of this study was to investigate the change in patellar position after open wedge high tibial osteotomy (OWHTO with distal tubercle osteotomy (DTO, comparing outcomes of conventional OWHTO in young adults with proximal tibia varus deformity but no arthritic manifestations. Thirty-three patients (mean age, 31.8 years subjected to OWHTO/DTO were matched with 30 patients (mean age, 33.5 years undergoing conventional OWHTO. Patellar position, as measured in pre- and postoperative standing lateral radiographs, was compared. Patellar height was assessed via Insall-Salvati ratio, modified Insall-Salvati ratio, Blackburne-Peel (BP index, Caton-Deschamps (CD index, and modified Miura-Kawamura index. Computed tomography was used to measure lateral patellar tilt and shift. In the OWHTO group, all patellar height indices decreased significantly following surgery. Although mean values of BP and CD indices decreased significantly in the OWHTO/DTO group, other determinants of patellar height showed no significant postoperative differences. Significant postoperative declines in average lateral patellar tilt were also evident in both groups, but pre- and postoperative lateral patellar shift did not differ significantly. OWHTO/DTO can be performed without significant changes in patellar height. The results obtained support that OWHTO/DTO is suitable for relatively young patients with proximal tibia vara but no arthritic change.

  16. Equivalent correction in scarf and chevron osteotomy in moderate and severe hallux valgus: a randomized controlled trial.

    NARCIS (Netherlands)

    Deenik, A.; Mameren, H. van; Visser, E. de; Waal Malefijt, M.C. de; Draijer, F.; Bie, R. de

    2008-01-01

    BACKGROUND: Chevron osteotomy is a widely accepted osteotomy for correction of hallux valgus.(18) Algorithms were developed to overcome the limitations of distal osteotomies. Scarf osteotomy has become popular as a versatile procedure that should be able to correct most cases of acquired hallux

  17. Staged bilateral carotid endarterectomy

    DEFF Research Database (Denmark)

    Schroeder, T; Sillesen, H; Engell, Hans Christian

    1986-01-01

    In a series of 56 staged bilateral carotid endarterectomies, new neurologic symptoms developed in 5% and 20% following the first and second procedure, respectively. All complications were transient or minor. The incidence of postendarterectomy hypertension was significantly higher following...... the second procedure, when operations were staged less than 3 weeks apart. A correlation between these hypertensive episodes and the occurrence of new neurologic symptoms could not be shown. However, as this correlation has been proved in several other reports, bilateral carotid endarterectomy is advised...... to be staged at least 3 weeks apart. In addition, a conservative attitude towards contralateral asymptomatic lesions is proposed....

  18. Extended plantar limb (modified) chevron osteotomy versus scarf osteotomy for hallux valgus correction: A randomised controlled trial.

    Science.gov (United States)

    Mahadevan, Devendra; Lines, Stephen; Hepple, Stephen; Winson, Ian; Harries, William

    2016-06-01

    The purpose of this RCT was to compare the extended plantar limb (modified) chevron osteotomy with the scarf osteotomy in correcting hallux valgus deformity and improving functional scores and patient satisfaction. Patients were randomly assigned and kept blind to surgical allocation. Cases requiring additional procedures including the Akin osteotomy were excluded. Outcomes were measured at 1 year following surgery. 84 patients (109 feet) were analysed (60 modified chevron; 49 Scarf). The mean age was 50.7 years (75F: 9M). Post-operative intermetatarsal angle (IMA) was significantly lower in the modified chevron group (5.8° versus 6.9°, p=0.045). Hallux valgus angle and distal metatarsal articular angle were similar. The magnitude of IMA correction with the modified chevron was also significantly greater (9.1° versus 7.1°, p=0.007). Both osteotomies produced comparable MOxFQ scores and satisfaction ratings. The modified chevron was superior to the scarf osteotomy in correcting IMA in hallux valgus deformity. Copyright © 2015 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  19. The history, evolution and basic science of osteotomy techniques

    Directory of Open Access Journals (Sweden)

    John Dabis

    2017-10-01

    Full Text Available Abstract Osteotomy techniques date back to Hippocrates circa 415 BC (Jones Hippocrates collected works I, Harvard University Press, Cambridge, 2006; Brorson in Clin Orthop Relat Res 467(7:1907–1914, 2009. There is debate about the best way to divide the bone surgically and which technique yields the best bone regenerate in lengthening; ensuring predictable new bone formation and healing of the osteotomy are the primary goals. We review the history and techniques of the osteotomy and consider the evidence for optimum bone formation. Methods discussed include variants of the ‘drill and osteotome’ technique, use of the Gigli saw and use of a power saw. Differences in bone formation through the different techniques are covered.

  20. A two-step crushed lava rock filter unit for grey water treatment at household level in an urban slum.

    Science.gov (United States)

    Katukiza, A Y; Ronteltap, M; Niwagaba, C B; Kansiime, F; Lens, P N L

    2014-01-15

    Decentralised grey water treatment in urban slums using low-cost and robust technologies offers opportunities to minimise public health risks and to reduce environmental pollution caused by the highly polluted grey water i.e. with a COD and N concentration of 3000-6000 mg L(-1) and 30-40 mg L(-1), respectively. However, there has been very limited action research to reduce the pollution load from uncontrolled grey water discharge by households in urban slums. This study was therefore carried out to investigate the potential of a two-step filtration process to reduce the grey water pollution load in an urban slum using a crushed lava rock filter, to determine the main filter design and operation parameters and the effect of intermittent flow on the grey water effluent quality. A two-step crushed lava rock filter unit was designed and implemented for use by a household in the Bwaise III slum in Kampala city (Uganda). It was monitored at a varying hydraulic loading rate (HLR) of 0.5-1.1 m d(-1) as well as at a constant HLR of 0.39 m d(-1). The removal efficiencies of COD, TP and TKN were, respectively, 85.9%, 58% and 65.5% under a varying HLR and 90.5%, 59.5% and 69%, when operating at a constant HLR regime. In addition, the log removal of Escherichia coli, Salmonella spp. and total coliforms was, respectively, 3.8, 3.2 and 3.9 under the varying HLR and 3.9, 3.5 and 3.9 at a constant HLR. The results show that the use of a two-step filtration process as well as a lower constant HLR increased the pollutant removal efficiencies. Further research is needed to investigate the feasibility of adding a tertiary treatment step to increase the nutrients and microorganisms removal from grey water. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Treatment of atrophic tibia non-unions according to 'diamond concept': Results of one- and two-step treatment.

    Science.gov (United States)

    Moghaddam, Arash; Zietzschmann, Severin; Bruckner, Thomas; Schmidmaier, Gerhard

    2015-10-01

    The successful treatment of atrophic tibia non-unions and tibia non-unions with large bone defects or infections is a major challenge in orthopedic and trauma surgery. This article evaluates the use of the 'diamond concept' using a one-step or two-step procedure according to 'Masquelet technique' in the treatment of atrophic tibia non-unions. Between February 2010 and March 2014, 102 patients with atrophic non-unions were treated according to the 'diamond concept' in our center. Ninety-nine were available for follow-up. Forty-nine received a one-step treatment (Group 1, G1) and 50 patients received a two-step treatment according to the 'Masquelet technique' (Group 2, G2). Clinical and radiological parameters were measured preoperatively as well as 4, 6, and 12 weeks and 6 and 12 months postoperatively. In order to evaluate the subjective health of patients, we used the SF-12 questionnaire. Data analysis was performed one year after treatment. The rate of consolidation in G1 was 84% and 80% in G2. The time to heal in G2 was 8.6 ± 2.9 months, which is significantly longer than in G1 being 6.9 ± 3.1 months. In comparison patients in G1/G2 had an average of 3.2/6.7 previous major surgeries. In G1, 4 of 8 patients who did not heal successfully showed positive intraoperative cultures. In G2, 26 patients (52%) initially presented with positive cultures. The results of the SF-12 questionnaire improved in both groups during the postoperative follow-up, but showed no significant differences between groups. In 29 patients a gentamycin-coated nail was used for reosteosynthesis. These patients showed by trend a lower rate of complications at a higher rate of consolidation. Our study showed that the 'diamond concept' is a suitable method for safely and effectively treating non-unions with large defects or infections. The use of an antibiotic-coated nail provides a therapeutic benefit. For large bone defects of infected non-unions the two-step procedure after Masquelet is an

  2. Bernese periacetabular osteotomy for hip dysplasia: Surgical technique and indications

    Science.gov (United States)

    Kamath, Atul F

    2016-01-01

    For young, active patients with healthy hip cartilage, pelvic osteotomy is a surgical option in to address hip pain and to improve mechanical loading conditions related to dysplasia. Hip dysplasia may lead to arthrosis at an early age due to poor coverage of the femoral head and abnormal loading of the joint articulation. In patients with symptomatic dysplasia and closed triradiate cartilage (generally over age 10), including adolescents and young adults (generally up to around age 40), the Bernese periacetabular osteotomy (PAO) is a durable technique for addressing underlying structural deformity. The PAO involves a modified Smith-Petersen approach. Advantages of the Bernese osteotomy include preservation of the weight-bearing posterior column of the hemi-pelvis, preservation of the acetabular blood supply, maintenance of the hip abductor musculature, and the ability to effect powerful deformity correction about an ideal center of rotation. There is an increasing body of evidence that preservation of the native hip can be improved through pelvic osteotomy. In contrast to hip osteotomy and joint preservation, the role of total hip arthroplasty in young, active patients with correctable hip deformity remains controversial. Moreover, the durability of hip replacement in young patients is inherently limited. Pelvic osteotomy should be considered the preferred method to address correctable structural deformity of the hip in the young, active patient with developmental dysplasia. The Bernese PAO is technically demanding, yet offers reproducible results with good long-term survivorship in carefully selected patients with preserved cartilage and the ability to meet the demands of rehabilitation. PMID:27190755

  3. Intra-Articular Osteotomy for Distal Humerus Malunion

    Directory of Open Access Journals (Sweden)

    René K. Marti

    2009-01-01

    Full Text Available Intra-articular osteotomy is considered in the rare case of malunion after a fracture of the distal humerus to restore humeral alignment and gain a functional arc of elbow motion. Traumatic and iatrogenic disruption of the limited blood flow to the distal end of the humerus resulting in avascular necrosis of capitellum or trochlea is a major pitfall of the this technically challenging procedure. Two cases are presented which illustrate the potential problems of intra-articular osteotomy for malunion of the distal humerus.

  4. Bilateral lunate intraosseous ganglia

    International Nuclear Information System (INIS)

    Pablos, J.M.; Valdes, J.C.; Gavilan, F.

    1998-01-01

    An intraosseous ganglion is a relatively uncommon, benign, cyst-like lesion that occurs in young and middle-aged adults. Most commonly seen adjacent to the hip, ankle, knee, or wrist, they are histologically identical to their soft tissue counterparts. A review of the literature revealed only two previously reported examples of bilateral symmetrical ganglia of the lunate bones. (orig.)

  5. Homogeneous bilateral block shifts

    Indian Academy of Sciences (India)

    Homogeneous bilateral block shifts. ADAM KORÁNYI. Department of Mathematics, The Graduate Center, City University of New York,. New York, NY 10016, USA. E-mail: Adam.Koranyi@lehman.cuny.edu. MS received 18 January 2013. Abstract. A new 3-parameter family of homogeneous 2-by-2 block shifts is described.

  6. Homogeneous bilateral block shifts

    Indian Academy of Sciences (India)

    A new 3-parameter family of homogeneous 2-by-2 block shifts is described. These are the first examples of irreducible homogeneous bilateral block shifts of block size larger than 1. Author Affiliations. Adam Korányi1. Department of Mathematics, The Graduate Center, City University of New York, New York, NY 10016, USA ...

  7. Bilateral breast carcinoma

    International Nuclear Information System (INIS)

    Kim, Eung Jo; Oh, Ki Keun

    1990-01-01

    We evaluate 311 breast cancer patients admitted to Yong Dong Severance Hospital Between October 1st 1985 and July 31th 1989, and were able to obtain the following conclusions. 1) There were 14(4.5%) bilateral breast cancers among the 311 confirmed breast cancers. 2) Among the bilateral breast cancers, 5(31%) were synchronous and 9(69%) metachronous. 3) Average interval between the first and the second breast cancer in metachronous cancers was 3.8 year(1-15 years). 4) Bilateral breast cancer was most prevalent in the fifth decade (6/14) with the mean age of 47 years. 5) Film mammogram and sonomammogram showed findings of typical breast malignancies. There was no additional specific findings for each cancer in bilateral breast cancers which was different from unilateral cancers. Therefor, in the patients with unilateral breast cancer, possibility of the second lesion in the contralateral side must be considered and a close follow up observation should be done for at least 3 years

  8. Bilateral akillesseneruptur hos nyretransplanterede

    DEFF Research Database (Denmark)

    Skovgaard, D; Feldt-Rasmussen, B F; Nimb, L

    1996-01-01

    Increased incidence of tendinitis and tendon ruptures is reported in recipients of a kidney transplant. Two cases of bilateral achilles tendon rupture after minimal trauma are described. Tendon ruptures are more frequent in individuals with kidney disease in dialysis or after transplantation comp...

  9. Homogeneous bilateral block shifts

    Indian Academy of Sciences (India)

    Douglas class were classified in [3]; they are unilateral block shifts of arbitrary block size (i.e. dim H(n) can be anything). However, no examples of irreducible homogeneous bilateral block shifts of block size larger than 1 were known until now.

  10. Bilateral meandering pulmonary veins

    Energy Technology Data Exchange (ETDEWEB)

    Thupili, Chakradhar R.; Udayasankar, Unni [Pediatric Imaging, Imaging Institute Cleveland Clinic, Cleveland, OH (United States); Renapurkar, Rahul [Imaging Institute Cleveland Clinic, Thoracic Imaging, L10, Cleveland, OH (United States)

    2015-06-15

    Meandering pulmonary veins is a rare clinical entity that can be mistaken for more complex congenital syndromes such as hypogenetic lung syndrome. We report imaging findings in a rare incidentally detected case of bilateral meandering pulmonary veins. We briefly discuss the role of imaging in diagnosing this condition, with particular emphasis on contrast-enhanced CT. (orig.)

  11. 4,6-connected fsb topology networks obtained through two-step crystal engineering of decorated trigonal prismatic nodes

    KAUST Repository

    Schoedel, Alexander

    2014-05-07

    A two-step crystal engineering strategy has been utilized to synthesize a new and versatile class of metal-organic materials, the first to exhibit 4,6-connected fsb topology. The new fsb networks are constructed from simple and inexpensive nodes (4-connected Zn(CO2)(py)2 tetrahedra; 6-connected Cr(μ3-O)(RCO2)6 trigonal prisms) and linker ligands (isonicotinate and various dicarboxylates). Further, since interpenetration is precluded, they can exhibit extra-large void volumes. These fsb nets are prototypal for what should ultimately become a large family of related structures given the ready availability of functionalized and/or expanded variants of both linker ligands. The fsb nets described herein therefore represent platforms or blueprints for a new family of ultrahigh surface area porous materials. © 2014 American Chemical Society.

  12. Study the effect of striping in two-step anodizing process on pore arrangement of nano-porous alumina

    International Nuclear Information System (INIS)

    Rahimi, M.H.; Saramad, S.; Tabaian, S.H.; Marashi, S.P.; Zolfaghari, A.; Mohammadalinezhad, M.

    2009-01-01

    Two-step anodic oxidation of aluminum is generally employed to produce the ordered porous anodized alumina (PAA). Dissolving away (striping) the oxide film after the first anodizing step plays a key role in the final arrangement of nano-pores. In this work, different striping durations between 1 and 6 h were applied to the sample that was initially anodized at a constant voltage of 40 V at 17 deg. C for 15 h. The striping duration of 3 h was realized as the optimum time for achieving the best ordering degree for the pores. Scanning electron microscopy (SEM) was used during and at the end of the process to examine the cross section and finishing surface of the specimens. Linear-angular fast Fourier transform (LA-FFT), an in-house technique based on MATLAB software, was employed to assess the ordering degree of the anodized samples.

  13. Phase gradient algorithm based on co-axis two-step phase-shifting interferometry and its application

    Science.gov (United States)

    Wang, Yawei; Zhu, Qiong; Xu, Yuanyuan; Xin, Zhiduo; Liu, Jingye

    2017-12-01

    A phase gradient method based on co-axis two-step phase-shifting interferometry, is used to reveal the detailed information of a specimen. In this method, the phase gradient distribution can only be obtained by calculating both the first-order derivative and the radial Hilbert transformation of the intensity difference between two phase-shifted interferograms. The feasibility and accuracy of this method were fully verified by the simulation results for a polystyrene sphere and a red blood cell. The empirical results demonstrated that phase gradient is sensitive to changes in the refractive index and morphology. Because phase retrieval and tedious phase unwrapping are not required, the calculation speed is faster. In addition, co-axis interferometry has high spatial resolution.

  14. Efficient One-Step Fusion PCR Based on Dual-Asymmetric Primers and Two-Step Annealing

    DEFF Research Database (Denmark)

    Liu, Yilan; Chen, Jinjin; Thygesen, Anders

    2018-01-01

    Gene splicing by fusion PCR is a versatile and widely used methodology, especially in synthetic biology. We here describe a rapid method for splicing two fragments by one-round fusion PCR with a dual-asymmetric primers and two-step annealing (ODT) method. During the process, the asymmetric...... intermediate fragments were generated in the early stage. Thereafter, they were hybridized in the subsequent cycles to serve as template for the target full-length product. The process parameters such as primer ratio, elongation temperature and cycle numbers were optimized. In addition, the fusion products...... produced with this method were successfully applied in seamless genome editing. The fusion of two fragments by this method takes less than 0.5 day. The method is expected to facilitate various kinds of complex genetic engineering projects with enhanced efficiency....

  15. Fast Method of Recovering Reference-Wave Intensity in Two-Step-Only Quadrature Phase-Shifting Holography

    Directory of Open Access Journals (Sweden)

    Wen-Jing Zhou

    2017-10-01

    Full Text Available We present a simple yet effective method, without the need for any additional recording of intensity maps or tremendous iterative computations, to recover reference-wave intensity resulting from the complex hologram acquired by quadrature phase-shifting holography. This is achieved by utilizing a certain area of interest in the complex hologram. We select a particular area in the complex hologram where there is negligible diffraction from the test sample to estimate the reference-wave intensity. The calculated intensity value allows us to extract exact phase distribution of the object in the context of two-step-only quadrature phase-shifting holography (TSO-PSH without the zeroth-order beam and the twin image noise on the reconstruction plane. Computer simulation and experimental results have been performed to verify the effectiveness and feasibility of our proposed method.

  16. A two-step method for spatial circle orientation with a structured light vision sensor and error analysis

    International Nuclear Information System (INIS)

    Wu, Bin; Ye, Shenghua; Xue, Ting

    2010-01-01

    A novel two-step method for spatial circle orientation with a structured light vision sensor is proposed for a 3D flexible visual inspection system guided by an industrial robot. Firstly the z coordinate of a spatial circle center is estimated, secondly the x and y coordinates are estimated with the center orientation relative to the camera optic center, and then its radius is computed. Simultaneously, the x, y and z coordinate orientation errors are analyzed in detail. It shows that the method is feasible and valid, and the orientation accuracy for the spatial circle exceeds 0.15 mm by experiment. It eliminates the bottleneck of the traditional orientation method with a stereovision sensor, and greatly expands the application of the structured light visual inspection system

  17. A cascaded two-step Kalman filter for estimation of human body segment orientation using MEMS-IMU.

    Science.gov (United States)

    Zihajehzadeh, S; Loh, D; Lee, M; Hoskinson, R; Park, E J

    2014-01-01

    Orientation of human body segments is an important quantity in many biomechanical analyses. To get robust and drift-free 3-D orientation, raw data from miniature body worn MEMS-based inertial measurement units (IMU) should be blended in a Kalman filter. Aiming at less computational cost, this work presents a novel cascaded two-step Kalman filter orientation estimation algorithm. Tilt angles are estimated in the first step of the proposed cascaded Kalman filter. The estimated tilt angles are passed to the second step of the filter for yaw angle calculation. The orientation results are benchmarked against the ones from a highly accurate tactical grade IMU. Experimental results reveal that the proposed algorithm provides robust orientation estimation in both kinematically and magnetically disturbed conditions.

  18. Efficient One-Step Fusion PCR Based on Dual-Asymmetric Primers and Two-Step Annealing.

    Science.gov (United States)

    Liu, Yilan; Chen, Jinjin; Thygesen, Anders

    2018-02-01

    Gene splicing by fusion PCR is a versatile and widely used methodology, especially in synthetic biology. We here describe a rapid method for splicing two fragments by one-round fusion PCR with a dual-asymmetric primers and two-step annealing (ODT) method. During the process, the asymmetric intermediate fragments were generated in the early stage. Thereafter, they were hybridized in the subsequent cycles to serve as template for the target full-length product. The process parameters such as primer ratio, elongation temperature and cycle numbers were optimized. In addition, the fusion products produced with this method were successfully applied in seamless genome editing. The fusion of two fragments by this method takes less than 0.5 day. The method is expected to facilitate various kinds of complex genetic engineering projects with enhanced efficiency.

  19. Breaking down polystyrene through the application of a two-step thermal degradation and bacterial method to produce usable byproducts.

    Science.gov (United States)

    Savoldelli, James; Tomback, Drew; Savoldelli, Hugh

    2017-02-01

    In this work, the objective is to examine a novel approach on the biodegradability of polystyrene is examined. A two-step method for the degradation of polystyrene to chemically useful products has been devised. Initially, polystyrene is liquefied via a thermal degradation procedure predominantly into styrene monomers at low temperatures and left to cool down. Application of microorganisms in a second step targets the breaking of the polymer into smaller organic molecules. Microorganisms tested were Rhodococcus zopfii stoecker, Enterococcus faecalis, Pseudomonas putida and Salmonella with the last two being the most effective. A third step is required to treat the organic products accordingly. The suggested method exhibits total conversion of polystyrene. While the method has only been examined on a small scale, its potential advantages for the recycling of polystyrene waste, are minimized energy costs due to low temperatures of thermal treatment used and the extremely fast degradation kinetics observed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Superthermostability of nanoscale TIC-reinforced copper alloys manufactured by a two-step ball-milling process

    Science.gov (United States)

    Wang, Fenglin; Li, Yunping; Xu, Xiandong; Koizumi, Yuichiro; Yamanaka, Kenta; Bian, Huakang; Chiba, Akihiko

    2015-12-01

    A Cu-TiC alloy, with nanoscale TiC particles highly dispersed in the submicron-grained Cu matrix, was manufactured by a self-developed two-step ball-milling process on Cu, Ti and C powders. The thermostability of the composite was evaluated by high-temperature isothermal annealing treatments, with temperatures ranging from 727 to 1273 K. The semicoherent nanoscale TiC particles with Cu matrix, mainly located along the grain boundaries, were found to exhibit the promising trait of blocking grain boundary migrations, which leads to a super-stabilized microstructures up to approximately the melting point of copper (1223 K). Furthermore, the Cu-TiC alloys after annealing at 1323 K showed a slight decrease in Vickers hardness as well as the duplex microstructure due to selective grain growth, which were discussed in terms of hardness contributions from various mechanisms.

  1. The effect of two-step α transfer reaction in the elastic scattering of 12C+24Mg

    International Nuclear Information System (INIS)

    Lichtenthaler Filho, R.; Lepine-Szily, A.; Villari, A.C.C.; Mittig, W.; Porto, V. de J.G.; Acquadro, C.V.

    1982-06-01

    Angular distribution of the elastic scattering 24 Mg( 12 C, 12 C) 24 Mg and of the 24 Mg( 12 C, 16 O) 20 Ne transfer reaction have been measured at 40 MeV incident energy, respectively in the 20 0 0 and 20 0 0 angular regions. The elastic scattering and transfer reactions were analysed with Frahn's closed formalism as well as with optical model calculations. The influence of the two-step α-transfer channel ( 12 C+ 24 Mg → 16 O+ 20 Ne → 12 C+ 24 Mg) on the elastic scattering was calculated explicitly using the coupled channel extension of the closed formalism. This calculation shows that the coupling between the α-transfer and elastic channel can account for the intermediate angle oscillations observed in the elastic scattering angular distributions. (Author) [pt

  2. Flexible fabrication of biomimetic compound eye array via two-step thermal reflow of simply pre-modeled hierarchic microstructures

    Science.gov (United States)

    Huang, Shengzhou; Li, Mujun; Shen, Lianguan; Qiu, Jinfeng; Zhou, Youquan

    2017-06-01

    A flexible fabrication method for the biomimetic compound eye (BCE) array is proposed. In this method, a triple-layer sandwich-like coating configuration was introduced, and the required hierarchic microstructures are formed with a simple single-scan exposure in maskless digital lithography. Taking advantage of the difference of glass transition point (Tg) between photoresists of each layer, the pre-formed hierarchic microstructures are in turn reflowed to the curved substrate and the BCE ommatidia in a two-step thermal reflow process. To avoid affecting the spherical substrate formed in the first thermal reflow, a non-contact strategy was proposed in the second reflow process. The measurement results were in good agreement with the designed BCE profiles. Results also showed that the fabricated BCE had good performances in optical test. The presented method is flexible, convenient, low-cost and can easily adapt to the fabrications of other optical elements with hierarchic microstructures.

  3. A commuter-based two-step floating catchment area method for measuring spatial accessibility of daycare centers.

    Science.gov (United States)

    Fransen, Koos; Neutens, Tijs; De Maeyer, Philippe; Deruyter, Greet

    2015-03-01

    This paper puts forward a commuter-based version of the two-step floating catchment area (2SFCA) method, which has gained acceptance in studies on spatial health care accessibility. Current implementations of the 2SFCA method are static in that they consider centroid-based night-time representations of the population. The proposed enhancement to the 2SFCA approach addresses this limitation by accounting for trip-chaining behavior. The presented method is illustrated in a case study of accessibility of daycare centers in the province East Flanders in Belgium. The results show significant spatial differences in accessibility between the original and commuter-based version of the 2SFCA (CB2SFCA). They highlight the importance of giving heed to more complex travel behavior in cases where the need for detailed accessibility calculations is apparent. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Improvement in surface morphology of GaSb buffer layer by two-step high and low temperature growth

    Science.gov (United States)

    Okumura, Shigekazu; Tomabechi, Shuichi; Suzuki, Ryo; Matsukura, Yusuke; Tsunoda, Koji; Kon, Jun-ichi; Nishino, Hironori

    2017-11-01

    The surface morphology of GaSb was investigated by changing growth conditions such as thermal oxide desorption temperature, growth temperature, and growth step by solid source molecular beam epitaxy. At high temperature growth, the pits caused by the thermal oxide desorption remained in the GaSb buffer layer surface, while the surface was sufficiently flattened. At low temperature growth, the pits disappeared, while the surface was not enough flattened even in the case of step-flow mode growth. Since the pits disappeared at lower growth temperature regardless of the growth mode, this behavior might be explained by the Ga migration length depending on the growth temperature. By applying two-step high/low temperature growth, where both growth steps proceed in step-flow mode, flat, a pit-free GaSb buffer surface could be obtained.

  5. Cryptosystem based on two-step phase-shifting interferometry and the RSA public-key encryption algorithm

    Science.gov (United States)

    Meng, X. F.; Peng, X.; Cai, L. Z.; Li, A. M.; Gao, Z.; Wang, Y. R.

    2009-08-01

    A hybrid cryptosystem is proposed, in which one image is encrypted to two interferograms with the aid of double random-phase encoding (DRPE) and two-step phase-shifting interferometry (2-PSI), then three pairs of public-private keys are utilized to encode and decode the session keys (geometrical parameters, the second random-phase mask) and interferograms. In the stage of decryption, the ciphered image can be decrypted by wavefront reconstruction, inverse Fresnel diffraction, and real amplitude normalization. This approach can successfully solve the problem of key management and dispatch, resulting in increased security strength. The feasibility of the proposed cryptosystem and its robustness against some types of attack are verified and analyzed by computer simulations.

  6. Two-step epigenetic Mendelian randomization: a strategy for establishing the causal role of epigenetic processes in pathways to disease

    Science.gov (United States)

    Relton, Caroline L; Davey Smith, George

    2012-01-01

    The burgeoning interest in the field of epigenetics has precipitated the need to develop approaches to strengthen causal inference when considering the role of epigenetic mediators of environmental exposures on disease risk. Epigenetic markers, like any other molecular biomarker, are vulnerable to confounding and reverse causation. Here, we present a strategy, based on the well-established framework of Mendelian randomization, to interrogate the causal relationships between exposure, DNA methylation and outcome. The two-step approach first uses a genetic proxy for the exposure of interest to assess the causal relationship between exposure and methylation. A second step then utilizes a genetic proxy for DNA methylation to interrogate the causal relationship between DNA methylation and outcome. The rationale, origins, methodology, advantages and limitations of this novel strategy are presented. PMID:22422451

  7. Internal friction behaviors of Ni-Mn-In magnetic shape memory alloy with two-step structural transformation

    Directory of Open Access Journals (Sweden)

    Zhen-ni Zhou

    2017-06-01

    Full Text Available The internal friction (IF behaviors of dual-phase Ni52Mn32In16 alloy with two-step structural transformation were investigated by dynamic mechanical analyzer. The IF peak for the martensite transformation (MT is an asymmetric shoulder rather than those sharp peaks for other shape memory alloys. The intermartensitic transformation (IMT peak has the maximum IF value. As the heating rate increases, the height of the IMT peak increases and its position is shifted to higher temperatures. In comparison with the IMT peak, the MT peak is independent on the heating rate. The starting temperatures of the IMT peak are strongly dependent on frequency, while the MT peak is weakly dependent. Meanwhile, the heights of both the MT and IMT peak rapidly decrease with increasing the frequency. This work also throws new light on their structural transformation mechanisms.

  8. Climatic change on the Gulf of Fonseca (Central America) using two-step statistical downscaling of CMIP5 model outputs

    Science.gov (United States)

    Ribalaygua, Jaime; Gaitán, Emma; Pórtoles, Javier; Monjo, Robert

    2018-05-01

    A two-step statistical downscaling method has been reviewed and adapted to simulate twenty-first-century climate projections for the Gulf of Fonseca (Central America, Pacific Coast) using Coupled Model Intercomparison Project (CMIP5) climate models. The downscaling methodology is adjusted after looking for good predictor fields for this area (where the geostrophic approximation fails and the real wind fields are the most applicable). The method's performance for daily precipitation and maximum and minimum temperature is analysed and revealed suitable results for all variables. For instance, the method is able to simulate the characteristic cycle of the wet season for this area, which includes a mid-summer drought between two peaks. Future projections show a gradual temperature increase throughout the twenty-first century and a change in the features of the wet season (the first peak and mid-summer rainfall being reduced relative to the second peak, earlier onset of the wet season and a broader second peak).

  9. A new continuous two-step molecular precursor route to rare-earth oxysulfides Ln2O2S

    International Nuclear Information System (INIS)

    De Crom, N.; Devillers, M.

    2012-01-01

    A continuous two-step molecular precursor pathway is designed for the preparation of rare-earth oxysulfides Ln 2 O 2 S (Ln=Y, La, Pr, Nd, Sm–Lu). This new route involves a first oxidation step leading to the rare-earth oxysulfate Ln 2 O 2 SO 4 which is subsequently reduced to the rare-earth oxysulfide Ln 2 O 2 S by switching to a H 2 –Ar atmosphere. The whole process occurs at a temperature significantly lower than usual solid state synthesis (T≤650 °C) and avoids the use of dangerous sulfur-based gases, providing a convenient route to the synthesis of the entire series of Ln 2 O 2 S. The molecular precursors consist in heteroleptic dithiocarbamate complexes [Ln(Et 2 dtc) 3 (phen)] and [Ln(Et 2 dtc) 3 (bipy)] (Et 2 dtc=N,N-diethyldithiocarbamate; phen=1,10-phenanthroline; bipy=2,2′-bipyridine) and were synthesized by a new high yield and high purity synthesis route. The nature of the molecular precursor determines the minimum synthesis temperature and influences therefore the purity of the final Ln 2 O 2 S crystalline phase. - Graphical abstract: A continuous two-step molecular precursor pathway was designed for the preparation of rare-earth oxysulfides Ln 2 O 2 S (Ln=Y, La, Pr, Nd, Sm–Lu), starting from heteroleptic dithiocarbamate complexes. The influence of the nature of the molecular precursor on the minimum synthesis temperature and on the purity of the final Ln 2 O 2 S crystalline phase is discussed. Highlights: ► A new high yield and high purity synthesis route of rare earth dithiocarbamates is described. ► These compounds are used as precursors in a continuous process leading to rare-earth oxysulfides. ► The oxysulfides are obtained under much more moderate conditions than previously described.

  10. Microleakage assessment of one- and two-step self-etch adhesive systems with ‎the low shrinkage composites

    Directory of Open Access Journals (Sweden)

    Razieh Hoseinifar

    2015-10-01

    Full Text Available BACKGROUND AND AIM: Different studies evaluating one-step self-etch (SE adhesive systems show contradictory findings, so the aim of this study was to compare the microleakage of one-step SE adhesive systems and CLEARFIL SE BOND (CSB (that serves as the “gold-standard” SE adhesive with low shrinkage composites. METHODS: In this in vitro study, Class V cavities with the occlusal margin in enamel and cervical margin in cementum were prepared on the buccal and lingual surfaces of 36 human premolars and molars (72 cavities. The enamel surfaces of the cavities were etched with 37% phosphoric acid and then the specimens were divided into six groups of 6 (12 cavities and the cavities were restored according bellow: Group 1 (Kalore-GC + G-Bond, Group 2 (Grandio + Futurabond NR, Group 3 (Aelite LS Posterior + All Bond SE, Group 4 (Kalore-GC + CSB, Group 5 (Grandio + CSB, and Group 6 (Aelite LS Posterior + CSB. All the specimens were thermocycled for 2000 cycles (5-55 °C and then placed in 0.5% basic fuchsine dye for 24 hours at 37 °C and finally sectioned and observed under the stereomicroscope. Data were analyzed using Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests at a P 0.050. There were no significant differences in microleakage among two-step and one-step SE adhesive systems on both the occlusal and gingival margins. CONCLUSION: According to this study, two-step SE adhesive system (CSB did not provide better marginal seal than the one-step SE adhesive systems.

  11. "Two-step" technique with OsiriXTM to evaluate feasibility of C2 pedicle for surgical fixation

    Directory of Open Access Journals (Sweden)

    Luis Miguel Sousa Marques

    2016-01-01

    Full Text Available Background: Surgical treatment of craniovertebral junction pathology has evolved considerably in recent decades with the implementation of short atlanto-axial fixation techniques, notwhithstanding increasing neurovascular risks. Also, there is strong evidence that fixation of C2 anatomical pedicle has the best biomechanical profile of the entire cervical spine. However, it is often difficult and misleading, to evaluate anatomical bony and vascular anomalies using the three orthogonal planes (axial, coronal, and sagittal of CT. Objectives: The authors describe an innovative and simple technique to evaluate the feasibility of C2 pedicle for surgical screw fixation using preoperative planning with the free DICOM (Digital Imaging and Communications in Medicine software OsiriX TM . Materials and Methods: The authors report the applicatin of this novel technique in 5 cases (3 traumatic, 1 Os Odontoideum, and 1 complex congenital malformation collected from our general case series of the Department in the last 5 years. Results: In this "proof of concept" study, the pre-operative analysis with the "two-step" tecnique was detrimental for choosing the surgical tecnique. Detailed post-operative analysis confirmed correct position of C2 screws without cortical breach. There were no complications or mortality reported. Conclusion: This "two-step" technique is an easy and reliable way to determine the feasibility of C2 pedicle for surgical fixation. The detailed tridimensional radiological preoperative evaluation of craniovertebral junction anatomy is critical to the sucess and safety of this surgeries, and can avoid, to certain degree, expensive intra-operative tridimensional imaging facilities.

  12. Effect of desensitizing agents on the microtensile bond strength of a two-step self-etch adhesive to dentin.

    Science.gov (United States)

    Arisu, Hacer Deniz; Dalkihç, Evrim; Üçtaşli, Mine Betül

    2011-01-01

    The aim of this in vitro study was to evaluate the effect of cervical hypersensitivity treatments (neodymium yttrium aluminum garnet [Nd:YAG] laser and conventional techniques) on the microtensile bond strengths of adhesives to treated dentin. The buccal cervical enamel of 42 freshly extracted human mandibular third molars was ground flat to expose the cervical dentin. The dentin surfaces were polished with a series of silicon carbide papers, and the smear was removed with an ethylenediamine tetra-acetic acid solution. The teeth were randomly divided into six groups as follows: group 1, Vivasens; group 2, BisBlock; group 3, fluoride gel; group 4, Nd:YAG laser; group 5, Clearfil SE + Nd:YAG laser; and group 6, no treatment (control). The specimens were then restored with a two-step self-etch adhesive, with the exception of group 5. Five specimens from each group were restored with a nanohybrid composite resin. The adhesive interface of two specimens from each group was examined using scanning electron microscopy. The specimens were sectioned perpendicularly to the adhesive interface to produce beams (adhesive area 1 mm(2)). The beams were then attached to a microtensile tester and stressed to failure at 1 mm/min. The data were compared using one-way analysis of variance at a significance level of 0.05. The microtensile bond strengths of the control group were significantly higher than those found for group 1, group 2, group 3, and group 4 (pexception of Clearfil SE + Nd:YAG laser) reduced the microtensile bond strength of a two-step self-etch adhesive to dentin.

  13. Two-Step Functional Innovation of the Stem-Cell Factors WUS/WOX5 during Plant Evolution.

    Science.gov (United States)

    Zhang, Yuzhou; Jiao, Yue; Jiao, Hengwu; Zhao, Huabin; Zhu, Yu-Xian

    2017-03-01

    WUS and WOX5, which are expressed, respectively, in the organizing center (OC) and the quiescent center (QC), are essential for shoot/root apical stem-cell maintenance in flowering plants. However, little is known about how these stem-cell factors evolved their functions in flowering plants. Here, we show that the WUS/WOX5 proteins acquired two distinct capabilities by a two-step functional innovation process in the course of plant evolution. The first-step is the apical stem-cell maintenance activity of WUS/WOX5, which originated in the common ancestor of ferns and seed plants, as evidenced by the interspecies complementation experiments, showing that ectopic expression of fern Ceratopteris richardii WUS-like (CrWUL) surrounding OC/QC, or exclusive OC-/QC-expressed gymnosperms/angiosperms WUS/WOX5 in Arabidopsis wus-1 and wox5-1 mutants, could rescue their phenotypes. The second-step is the intercellular mobility that emerged in the common ancestor of seed plants after divergence from the ferns. Evidence for this includes confocal imaging of GFP fusion proteins, showing that WUS/WOX5 from seed plants, rather than from the fern CrWUL, can migrate into cells adjacent to the OC/QC. Evolutionary analysis showed that the WUS-like gene was duplicated into two copies prior to the divergence of gymnosperms/angiosperms. Then the two gene copies (WUS and WOX5) have undergone similar levels of purifying selection, which is consistent with their conserved functions in angiosperm shoot/root stem-cell maintenance and floral organ formation. Our results highlight the critical roles and the essential prerequisites that the two-step functional innovation of these genes performs and represents in the origin of flowering plants. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  14. Production of ultrasensitive generic monoclonal antibodies against major aflatoxins using a modified two-step screening procedure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Daohong [Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062 (China); Li Peiwu [Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062 (China); Quality Inspection and Test Center for Oilseeds and Products of Ministry of Agriculture, Wuhan 430062 (China)], E-mail: peiwuli@oilcrops.cn; Zhang Qi; Zhang Wen; Huang Yanling; Ding Xiaoxia; Jiang Jun [Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062 (China); Quality Inspection and Test Center for Oilseeds and Products of Ministry of Agriculture, Wuhan 430062 (China)

    2009-03-16

    Monoclonal antibodies (McAbs) cross-reactive with four major aflatoxins were achieved using a modified two-step screening procedure. The first step was twice modified indirect enzyme-linked immunosorbent assay (ELISA) and resulted in positive hybridomas and hapten-specific antibodies. The modified indirect competitive ELISA (ciELISA) was the second step, in which the competition incubation time was decreased to 30 min, aflatoxin B{sub 1}, B{sub 2}, G{sub 1} and G{sub 2} were all used as competitors, the concentrations of four aflatoxins were gradiently decreased in each screening. 2-3 subclonings were performed after every modified fusion and resulted in eight hybridomas that secreted antibodies with good cross-reactivity and high affinity to four aflatoxins. Five McAbs were chosen for further analysis. Of the five, two antibodies had similar reaction efficiency with aflatoxin B{sub 1}, B{sub 2} and G{sub 1} but showed a weak cross-reaction to G{sub 2}. Another two had almost identical reaction capability with four aflatoxins. One clone 1C11 exhibited the highest sensitivity for all four aflatoxins. The concentrations of aflatoxin B{sub 1}, B{sub 2}, G{sub 1} and G{sub 2} at 50% inhibition for 1C11 were 1.2, 1.3, 2.2 and 18.0 pg mL{sup -1} respectively. This is the most sensitive for all four major aflatoxins described so far. The results indicated that the modified two-step screening procedure had superiority and these antibodies could be used for simultaneous analysis of total aflatoxins.

  15. Semi-automated hydrophobic interaction chromatography column scouting used in the two-step purification of recombinant green fluorescent protein.

    Science.gov (United States)

    Stone, Orrin J; Biette, Kelly M; Murphy, Patrick J M

    2014-01-01

    Hydrophobic interaction chromatography (HIC) most commonly requires experimental determination (i.e., scouting) in order to select an optimal chromatographic medium for purifying a given target protein. Neither a two-step purification of untagged green fluorescent protein (GFP) from crude bacterial lysate using sequential HIC and size exclusion chromatography (SEC), nor HIC column scouting elution profiles of GFP, have been previously reported. Bacterial lysate expressing recombinant GFP was sequentially adsorbed to commercially available HIC columns containing butyl, octyl, and phenyl-based HIC ligands coupled to matrices of varying bead size. The lysate was fractionated using a linear ammonium phosphate salt gradient at constant pH. Collected HIC eluate fractions containing retained GFP were then pooled and further purified using high-resolution preparative SEC. Significant differences in presumptive GFP elution profiles were observed using in-line absorption spectrophotometry (A395) and post-run fluorimetry. SDS-PAGE and western blot demonstrated that fluorometric detection was the more accurate indicator of GFP elution in both HIC and SEC purification steps. Comparison of composite HIC column scouting data indicated that a phenyl ligand coupled to a 34 µm matrix produced the highest degree of target protein capture and separation. Conducting two-step protein purification using the preferred HIC medium followed by SEC resulted in a final, concentrated product with >98% protein purity. In-line absorbance spectrophotometry was not as precise of an indicator of GFP elution as post-run fluorimetry. These findings demonstrate the importance of utilizing a combination of detection methods when evaluating purification strategies. GFP is a well-characterized model protein, used heavily in educational settings and by researchers with limited protein purification experience, and the data and strategies presented here may aid in development other of HIC-compatible protein

  16. Dentin Bonding Durability of Two-step Self-etch Adhesives with Improved of Degree of Conversion of Adhesive Resins.

    Science.gov (United States)

    Sato, Kento; Hosaka, Keiichi; Takahashi, Masahiro; Ikeda, Masaomi; Tian, Fucong; Komada, Wataru; Nakajima, Masatoshi; Foxton, Richard; Nishitani, Yoshihiro; Pashley, David H; Tagami, Junji

    To evaluate (1) the initial and long-term microtensile bond strengths of two-step self-etch adhesives with different degrees of conversion (DC); (2) the elastic modulus of the respective adhesive resins; (3) the water sorption of the respective adhesive resins. Two two-step self-etch adhesives, Clearfil SE Bond (CSE) and Clearfil SE Bond 2 (CSE2) were used in this study. The DC was determined using ATR/FT-IR with a time-based spectrum analysis. Midcoronal flat dentin surfaces of 24 human molars were prepared with 600-grit SiC paper for microtensile bond strength (µTBS) testing. CSE and CSE2 were applied to the dentin surfaces according to the manufacturer's instructions, followed by composite buildups. The µTBS was measured after water storage for 24 h, 6 months, and 1 year. The elastic modulus (before and after 1 month of water immersion) was determined by the three-point flexural bending test and water sorption values by the water sorption test. CSE2 showed significantly higher DC than CSE. The µTBS of CSE2 was significantly higher than that of CSE in all water storage periods. One-year water storage decreased the µTBS of CSE; however, it did not decrease that of CSE2. Regarding the polymerized adhesive resins, the elastic modulus of CSE2 was significantly higher than that of CSE before and after water immersion (p self-etch adhesives resists water aging and improves the initial bond strengths and durability of the resin-dentin bond.

  17. Two-step synthesis of highly emissive C/ZnO hybridized quantum dots with a broad visible photoluminescence

    International Nuclear Information System (INIS)

    He, Liangjie; Mei, Shiliang; Chen, Qiuhang; Zhang, Wanlu; Zhang, Jie; Zhu, Jiatao; Chen, Guoping; Guo, Ruiqian

    2016-01-01

    Graphical abstract: The formation schematics of the C/ZnO hybridized QDs. - Highlights: • C/ZnO hybridized quantum dots (QDs) were formed via a two-step method. • The broad visible emission from the C/ZnO QDs with a high quantum yield (QY) was obtained. • The mechanism of the fluorescence enhancement of the C/ZnO QDs was proposed. • The concentration of the CDs and refluxing temperature are identified as two key parameters. • The as-prepared QDs could offer a promising solution for the future-generation white LED. - Abstract: In situ growth of ZnO layer on the surface of carbon dots was realized via a two-step method, which resulted in an enhancement of the broad visible emission with a high quantum yield. Influence of the refluxing time, the temperature and the oleylamine/octadecene ratio was investigated to address the key factors on the preparation of the carbon dots. Under the optimal conditions, the carbon dots with an average diameter of 3.4 ± 0.4 nm and a photoluminescence quantum yield of 29.3% were achieved. Remarkable improvements of photoluminescence were achieved by the hybridization of the ZnO layer, which can eliminate the surface-trap from the C cores and form the new centers of emission. The synergistic effect arising from the C/ZnO hybridized structure obviously broadened the visible emission and enhanced their photoluminescence quantum yield from 29.3% to 47.3%. The as-prepared highly emissive quantum dots exhibited a broad and stable emission with the Commission Internationaled ‘E’ clairage chromaticity coordinate of (0.23, 0.34), which could offer a promising solution for the future-generation white light emitting diodes.

  18. Two-step synthesis of highly emissive C/ZnO hybridized quantum dots with a broad visible photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    He, Liangjie; Mei, Shiliang; Chen, Qiuhang; Zhang, Wanlu [Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Institute for Electric Light Sources, Fudan University, Shanghai 200433 (China); Zhang, Jie [Laboratory of Advanced Materials, Fudan University, Shanghai 200438 (China); Zhu, Jiatao [Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Institute for Electric Light Sources, Fudan University, Shanghai 200433 (China); Chen, Guoping [School of Information Science and Technology, Fudan University, Shanghai 200433 (China); Guo, Ruiqian, E-mail: rqguo@fudan.edu.cn [Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Institute for Electric Light Sources, Fudan University, Shanghai 200433 (China)

    2016-02-28

    Graphical abstract: The formation schematics of the C/ZnO hybridized QDs. - Highlights: • C/ZnO hybridized quantum dots (QDs) were formed via a two-step method. • The broad visible emission from the C/ZnO QDs with a high quantum yield (QY) was obtained. • The mechanism of the fluorescence enhancement of the C/ZnO QDs was proposed. • The concentration of the CDs and refluxing temperature are identified as two key parameters. • The as-prepared QDs could offer a promising solution for the future-generation white LED. - Abstract: In situ growth of ZnO layer on the surface of carbon dots was realized via a two-step method, which resulted in an enhancement of the broad visible emission with a high quantum yield. Influence of the refluxing time, the temperature and the oleylamine/octadecene ratio was investigated to address the key factors on the preparation of the carbon dots. Under the optimal conditions, the carbon dots with an average diameter of 3.4 ± 0.4 nm and a photoluminescence quantum yield of 29.3% were achieved. Remarkable improvements of photoluminescence were achieved by the hybridization of the ZnO layer, which can eliminate the surface-trap from the C cores and form the new centers of emission. The synergistic effect arising from the C/ZnO hybridized structure obviously broadened the visible emission and enhanced their photoluminescence quantum yield from 29.3% to 47.3%. The as-prepared highly emissive quantum dots exhibited a broad and stable emission with the Commission Internationaled ‘E’ clairage chromaticity coordinate of (0.23, 0.34), which could offer a promising solution for the future-generation white light emitting diodes.

  19. A Comparison of Two-Step Tuberculin Skin Test between Health-Care Workers and Nonhospital Employees

    Directory of Open Access Journals (Sweden)

    Iraj Nikokar

    2010-09-01

    Full Text Available Background: The tuberculin test is widely used to identify tuberculosisinfection. Some individuals infected with Mycobacteriumtuberculosis may have an initial negative skin test reactionto tuberculin. The two step purified protein derivative skin testcan decrease misinterpretation of tuberculin test .This study wasaimed at comparing the two- step tuberculin skin test and boosterphenomenon in health care workers and non hospital employees.Methods: One hundred and eighty five health service employeesfrom Razi University Hospital and 181 non hospitalemployees were subjected to an initial tuberculin skin test.Those who were negative on the first test underwent a secondone 2 weeks later. The reactions to the tests were measured 72hours later. Tests with an induration of ≥ 10 mm was consideredpositive. Moreover, second tests with an induration of atleast 6 mm increase relative to the relevant first tests wereconsidered positive.Results: Compared to non hospital employees (n=79, 43.6%, asignificantly higher number of health care workers (n=113,61.1% were positive on the first tuberculin test. 18.5 % of healthcare workers and 31.5% of non hospital employees demonstrateda boosted reaction after the second tuberculin test. The occurrenceof boosted reaction was significantly associated with ageboth groups. There was no association between the presence ofBCG scars and the occurrence of boosted reaction.Conclusion: the present study shows that the prevalence of TBwas higher among health care worker than non hospital employees.Moreover, it demonstrated that non hospital employeeshad a higher age-associated booster reaction to the second tuberculinskin test than health care workers. Therefore, to avoidmissing false negative cases, it would be necessary to do a secondtuberculin test for subjects with a negative reaction to theinitial test, especially in subjects older than 40 years.

  20. In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method.

    Science.gov (United States)

    Wu, Xiaoguang; Zhao, Xu; Li, Yi; Yang, Tao; Yan, Xiujuan; Wang, Ke

    2015-09-01

    In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO3 layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO3 layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO3 coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Developing a two-step heat treatment for inactivating desiccation-adapted Salmonella spp. in aged chicken litter.

    Science.gov (United States)

    Chen, Zhao; Wang, Hongye; Jiang, Xiuping

    2015-02-01

    The effectiveness of a two-step heat treatment for eliminating desiccation-adapted Salmonella spp. in aged chicken litter was evaluated. The aged chicken litter with 20, 30, 40, and 50% moisture contents was inoculated with a mixture of four Salmonella serotypes for a 24-h adaptation. Afterwards, the inoculated chicken litter was added into the chicken litter with the adjusted moisture content for a 1-h moist-heat treatment at 65 °C and 100% relative humidity inside a water bath, followed by a dry-heat treatment in a convection oven at 85 °C for 1 h to the desired moisture level (heat treatment, the populations of Salmonella in aged chicken litter at 20 and 30% moisture contents declined from ≈6.70 log colony-forming units (CFU)/g to 3.31 and 3.00 log CFU/g, respectively. After subsequent 1-h dry-heat treatment, the populations further decreased to 2.97 and 2.57 log CFU/g, respectively. Salmonella cells in chicken litter with 40% and 50% moisture contents were only detectable by enrichment after 40 and 20 min of moist-heat treatment, respectively. Moisture contents in all samples were reduced to dry-heat process. Our results demonstrated that the two-step heat treatment was effective in reducing >5.5 logs of desiccation-adapted Salmonella in aged chicken litter with moisture content at or above 40%. Clearly, the findings from this study may provide the chicken litter processing industry with an effective heat treatment method for producing Salmonella-free chicken litter.

  2. Semi-Automated Hydrophobic Interaction Chromatography Column Scouting Used in the Two-Step Purification of Recombinant Green Fluorescent Protein

    Science.gov (United States)

    Murphy, Patrick J. M.

    2014-01-01

    Background Hydrophobic interaction chromatography (HIC) most commonly requires experimental determination (i.e., scouting) in order to select an optimal chromatographic medium for purifying a given target protein. Neither a two-step purification of untagged green fluorescent protein (GFP) from crude bacterial lysate using sequential HIC and size exclusion chromatography (SEC), nor HIC column scouting elution profiles of GFP, have been previously reported. Methods and Results Bacterial lysate expressing recombinant GFP was sequentially adsorbed to commercially available HIC columns containing butyl, octyl, and phenyl-based HIC ligands coupled to matrices of varying bead size. The lysate was fractionated using a linear ammonium phosphate salt gradient at constant pH. Collected HIC eluate fractions containing retained GFP were then pooled and further purified using high-resolution preparative SEC. Significant differences in presumptive GFP elution profiles were observed using in-line absorption spectrophotometry (A395) and post-run fluorimetry. SDS-PAGE and western blot demonstrated that fluorometric detection was the more accurate indicator of GFP elution in both HIC and SEC purification steps. Comparison of composite HIC column scouting data indicated that a phenyl ligand coupled to a 34 µm matrix produced the highest degree of target protein capture and separation. Conclusions Conducting two-step protein purification using the preferred HIC medium followed by SEC resulted in a final, concentrated product with >98% protein purity. In-line absorbance spectrophotometry was not as precise of an indicator of GFP elution as post-run fluorimetry. These findings demonstrate the importance of utilizing a combination of detection methods when evaluating purification strategies. GFP is a well-characterized model protein, used heavily in educational settings and by researchers with limited protein purification experience, and the data and strategies presented here may aid in

  3. Revisional Surgery for Hallux Valgus with Serial Osteotomies at Two Levels

    Directory of Open Access Journals (Sweden)

    Jason B. T. Lim

    2011-01-01

    Full Text Available The aetiology and form of hallux valgus (HV is varied with many corrective procedures described. We report a 39-year-old woman, previously treated with a Chevron osteotomy, who presented with recurrent right HV, metatarsus primus varus, and associated bunion. Osteotomies were performed at two levels as a revisional procedure. This report highlights (1 limitations of the Chevron osteotomy and (2 the revisional procedure of the two level osteotomies: (i proximal opening-wedge basal osteotomy and (ii distal short Scarf with medial closing wedges. If a Chevron osteotomy is used inappropriately, for example, in an attempt to correct too large a deformity, it may angulate laterally causing a malunion with an increased distal metatarsal articular angle. Secondly, it is feasible to correct this combined deformity using a combination of proximal opening-wedge and distal short Scarf osteotomies.

  4. Biomechanical Factors in Planning of Periacetabular Osteotomy

    Directory of Open Access Journals (Sweden)

    Noushin eNiknafs

    2013-12-01

    Full Text Available This study addresses the effects of cartilage thickness distribution and compressive properties in the context of optimal alignment planning for periacetabular osteotomy (PAO. The Biomechanical Guidance System (BGS is a computer-assisted surgical suite assisting surgeon’s in determining the most beneficial new alignment of a patient’s acetabulum. The BGS uses biomechanical analysis of the hip to find this optimal alignment. Articular cartilage is an essential component of this analysis and its physical properties can affect contact pressure outcomes. Patient-specific hip joint models created from CT scans of a cohort of 29 dysplastic subjects were tested with four different cartilage thickness profiles (one uniform and threenonuniform and two sets of compressive characteristics. For each combination of thickness distribution and compressive properties, the optimal alignment of the acetabulum was found; the resultant geometric and biomechanical characterization of the hip were compared among the optimal alignments. There was an average decrease of 49.2 +/- 22.27% in peak contact pressure from the preoperative to the optimal alignment over all patients. We observed an average increase of 19 +/- 7.7 degrees in center-edge angle and an average decrease of 19.5 +/- 8.4 degrees in acetabular index angle from the preoperative case to the optimized plan. The optimal alignment increased the lateral coverage of the femoral head and decreased the obliqueness of the acetabular roof in all patients. These anatomical observations were independent of the choice for either cartilage thickness profile, or compressive properties. While patient-specific acetabular morphology is essential for surgeons in planning PAO, the predicted optimal alignment of the acetabulum was not significantly sensitive to the choice of cartilage thickness distribution over the acetabulum. However, in all groups the biomechanically predicted optimal alignment resulted in decreased

  5. Correction of Hallux Valgus Interphalangeus With an Osteotomy of the Distal End of the Proximal Phalanx (Distal Akin Osteotomy).

    Science.gov (United States)

    Vander Griend, Robert

    2017-02-01

    Operative correction of a symptomatic hallux valgus interphalangeus (HVI) deformity is often achieved with an osteotomy at the proximal end of the proximal phalanx (Akin osteotomy). However, the apex of the typical HVI deformity (center of rotation angle) is at the interphalangeal joint of the hallux. This study was done to evaluate the results of performing a medial closing wedge osteotomy at the distal end of the proximal phalanx. Thirty-three patients (33 feet) underwent an osteotomy at the distal end of the proximal phalanx for correction of HVI. All of the patients had other forefoot deformities which were corrected at the same time. Eight of these were revision procedures of prior forefoot operations. The length of follow-up was determined by the associated procedures with a minimum follow-up of 4 months. The preoperative hallux valgus interphalangeus angle averaged 16 degrees of valgus (range 7-32 degrees) and was corrected to an average of 2 degrees of valgus (range 5 degrees valgus to 5 degrees varus). All of the patients were satisfied with the postoperative appearance and function of the first toe. Because of simultaneous correction of numerous other forefoot problems, it was not possible to specifically isolate or evaluate the effects and benefits of this osteotomy using outcomes measures. There was one intraoperative complication resulting in a fracture extending into the adjacent IP joint. Correction of an HVI deformity can be achieved with an osteotomy at the distal end of the proximal phalanx. This was a safe technique with few complications and with good results in terms of both correction and patient satisfaction. Level IV, retrospective case series.

  6. MRI changes in the temporomandibular joint following mandibular setback surgery using sagittal split ramus osteotomy with rigid fixation.

    Science.gov (United States)

    Takahara, Namiaki; Kabasawa, Yuji; Sato, Masaru; Tetsumura, Akemi; Kurabayashi, Tohru; Omura, Ken

    2017-01-01

    This study examined the changes in temporomandibular joint dysfunction (TMD) symptoms and investigated the variations in the disc position, disc and condylar morphology following sagittal split ramus osteotomy (SSRO) with rigid fixation in patients with mandibular prognathism. Furthermore, the authors examined the correlation between mandibular setback and TMD symptoms. The study included 24 Japanese patients with jaw deformities who were treated using bilateral SSRO and Le Fort I osteotomy. The clinical and magnetic resonance imaging findings in the temporomandibular joint were evaluated preoperatively and at three and six months postoperatively. The preoperative TMD symptoms were significantly associated with the prevalence of TMD symptoms at six months postoperatively. Anterior disc displacement improved in four joints with slight displacement and with no morphological change. There were no postoperative changes in condylar morphology. There was no significant correlation between mandibular setback and the postoperative TMD symptoms. Postoperative TMD symptoms may be influenced mainly by preoperative TMD symptoms rather than mandibular setback using SSRO with rigid fixation. Therefore, patients with TMD symptoms require physical examination and MRI for appropriate diagnosis preoperatively.

  7. Long-Term Stability of Pre-Orthodontic Orthognathic Bimaxillary Surgery Using Intraoral Vertical Ramus Osteotomy Versus Conventional Surgery.

    Science.gov (United States)

    Jeong, Jeong-Hwa; Choi, Sung-Hwan; Kim, Kee-Deog; Hwang, Chung-Ju; Lee, Sang-Hwy; Yu, Hyung-Seog

    2018-02-20

    The aim of the present study was to compare the long-term stability of bimaxillary surgery using an intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontic treatment. The present retrospective study included 31 consecutive patients with skeletal Class III malocclusions who had undergone bimaxillary surgery (Le Fort I osteotomy and bilateral IVRO). Patients were divided into 2 groups based on treatment type: pre-orthodontic orthognathic surgery (POGS; n = 17) and conventional surgery with presurgical orthodontic treatment (CS; n = 14). Lateral cephalograms were obtained before surgery, 1 day after surgery, 1 month after surgery, 1 year after surgery, and 2 years after surgery to evaluate skeletal and soft tissue changes between the 2 groups. Data were analyzed using χ 2 tests, Mann-Whitney U tests, repeated-measures analyses of variance, and independent t tests. There was no significant difference in skeletal or soft tissue measurements-with the exception of the angle between the sella-and-nasion plane and the occlusal plane (SN-OP; P stability in patients with skeletal Class III malocclusion. Copyright © 2018. Published by Elsevier Inc.

  8. Comparison between universal adhesives and two-step self-etch adhesives in terms of dentin bond fatigue durability in self-etch mode.

    Science.gov (United States)

    Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Watanabe, Hidehiko; Johnson, William W; Latta, Mark A; Miyazaki, Masashi

    2017-06-01

    This aim of this study was to compare universal adhesives and two-step self-etch adhesives in terms of dentin bond fatigue durability in self-etch mode. Three universal adhesives - Clearfil Universal, G-Premio Bond, and Scotchbond Universal Adhesive - and three-two-step self-etch adhesives - Clearfil SE Bond, Clearfil SE Bond 2, and OptiBond XTR - were used. The initial shear bond strength and shear fatigue strength of resin composite bonded to adhesive on dentin in self-etch mode were determined. Scanning electron microscopy observations of fracture surfaces after bond strength tests were also made. The initial shear bond strength of universal adhesives was material dependent, unlike that of two-step self-etch adhesives. The shear fatigue strength of Scotchbond Universal Adhesive was not significantly different from that of two-step self-etch adhesives, unlike the other universal adhesives. The shear fatigue strength of universal adhesives differed depending on the type of adhesive, unlike those of two-step self-etch adhesives. The results of this study encourage the continued use of two-step self-etch adhesive over some universal adhesives but suggest that changes to the composition of universal adhesives may lead to a dentin bond fatigue durability similar to that of two-step self-etch adhesives. © 2017 Eur J Oral Sci.

  9. Bilateral matrix-exponential distributions

    DEFF Research Database (Denmark)

    Bladt, Mogens; Esparza, Luz Judith R; Nielsen, Bo Friis

    2012-01-01

    In this article we define the classes of bilateral and multivariate bilateral matrix-exponential distributions. These distributions have support on the entire real space and have rational moment-generating functions. These distributions extend the class of bilateral phasetype distributions of [1]....... As an application we demonstrate that certain multivariate disions, which are governed by the underlying Markov jump process generating a phasetype distribution, have a bilateral matrix-exponential distribution at the time of absorption, see also [4]....

  10. Comparison of three approaches of Bernese periacetabular osteotomy

    Directory of Open Access Journals (Sweden)

    Luo DZ

    2016-01-01

    Full Text Available Dianzhong Luo, Hong Zhang, Weijia Zhang Division of Joint Surgery and Sport Medicine, Department of Orthopaedics, First Affiliated Hospital of Chinese PLA General Hospital, Beijing, People’s Republic of China Background: Developmental dysplasia of the hip is a common disease and treated with various surgical approaches. Improved ilioinguinal (I-I approach, two-incision Smith-Peterson (TSP approach, and modified Smith-Peterson (MSP approach are three main approaches; however, they are rarely compared. The present study compared the operative time, blood loss, intraoperative and postoperative allogeneic blood transfusion, and postoperative complications of these three different approaches. Hypothesis: Surgical approach does not influence the operation time, blood loss, and complications of periacetabular osteotomy. Level of evidence: Level III. Case–control study. Patients and methods: In a total of 101 hips of 95 cases, from February 2010 to July 2011, three different approaches of Bernese periacetabular osteotomy, I-I, TSP, and MSP, were conducted. The operation time, intraoperative bleeding, allogeneic blood transfusion, and early complications in different operation approaches were compared by a retrospective study when there were similar ages, genders, and lesions. Results: Among the three approaches, I-I had less operation time and more blood loss (P<0.05, TSP had less blood loss (P<0.05 but more complications, and MSP had less blood loss (P<0.05 and less complications. Discussion: The MSP approach is superior to the other two approaches in doing periacetabular osteotomy. Keywords: periacetabular osteotomy, operation approaches, complications

  11. Trochanteric reduction osteotomy as a treatment for refractory trochanteric bursitis

    NARCIS (Netherlands)

    Govaert, L. H. M.; van der Vis, H. M.; Marti, R. K.; Albers, G. H. R.

    2003-01-01

    We describe a new operative procedure for patients with chronic trochanteric bursitis. Between March 1994 and May 2000, a trochanteric reduction osteotomy was performed on ten patients (12 hips). All had received conservative treatment for at least one year. Previous surgical treatment with a

  12. Horizontal osteotomy for reconstruction of the narrow edentulous mandible

    NARCIS (Netherlands)

    Raghoebar, GM; Batenburg, RHK; Meijer, HJA; Vissink, A

    The aim of this retrospective study was to evaluate the applicability of a horizontal osteotomy procedure for reconstruction of a narrow edentulous mandible in order to enable insertion of implants. In 7 edentulous patients a narrow inferior alveolar ridge was reconstructed with autogenous bone

  13. Mathematical Simulation of Osteotomy, Numerical Analysis and Results

    Czech Academy of Sciences Publication Activity Database

    Nedoma, Jiří; Stehlík, J.

    1995-01-01

    Roč. 63, 1/3 (1995), s. 421-438 ISSN 0377-0427. [Modelling'94. Prague, 29.08.1994-02.09.1994] R&D Projects: GA ČR GA308/95/0304 Keywords : mathematical modelling in orthopeady * osteotomy * contact problems * variational inequality * preconditioned conjugate gradient method Impact factor: 0.373, year: 1995

  14. Sugioka's osteotomy for femoral-head necrosis in young Caucasians.

    NARCIS (Netherlands)

    Rijnen, W.H.C.; Gardeniers, J.W.M.; Westrek, B.; Buma, P.; Schreurs, B.W.

    2005-01-01

    The transtrochanteric rotational osteotomy described by Sugioka is used to preserve the femoral head and to prevent secondary osteoarthritis in young patients with osteonecrosis of the femoral head. Several Japanese studies have shown favourable results, but European and American studies were

  15. Bilateral renal calculi

    Science.gov (United States)

    Sreenevasan, G

    1974-01-01

    Bilateral renal calculi were present in 114 (10.7%) of 1,070 cases of proved urinary calculus admitted to the Urological Department of the General Hospital, Kuala Lumpur, during the period November 1968—May 1973. The management of bilateral renal calculi is discussed with reference to the first 100 cases in this series. The introduction of renography has greatly facilitated the decision as to which kidney should be operated on first. The management of patients with and without uraemia is discussed and the use of the modified V and V—Y incisions for the removal of staghorn calculi is described. Complications and results are briefly reviewed. ImagesFig. 1Fig. 4Fig. 6Fig. 7 PMID:4845653

  16. Bilateral tuberculate supernumerary teeth.

    Science.gov (United States)

    Eigbobo, Joycelyn Odegua; Osagbemiro, Babatope Bamidele

    2011-05-16

    Supernumerary teeth are teeth in excess of the normal series occurring in any region of the dental arch. They are located mostly in the anterior maxillary region and are classified according to their location and morphology. The tuberculate type of supernumerary tooth possesses more than one cusp or tubercle (barrel shaped). It is rare to find bilateral tuberculate supernumerary teeth in the premaxillary region and when found they rarely erupt. This report describes a 13-year-old boy with erupted palatally placed bilateral tuberculate supernumerary teeth. The presence of these supernumerary teeth led to the labial displacement and rotations of the anterior maxillary teeth. The treatment involved extraction of the supernumerary teeth and a referral for orthodontic management of the crowding, displacement and rotations. The occurrence of erupted palatally placed tuberculate anterior teeth in this case is a rare experience. However, the associated orthodontic problems are within familiar spectrum.

  17. Bilateral Wilms' tumor

    International Nuclear Information System (INIS)

    Malcolm, A.W.; Jaffe, N.; Folkman, M.J.; Cassady, J.R.

    1980-01-01

    Twenty children with bilateral Wilms' tumor were presented to the Children's Hospital Medical Center and Children's Cancer Research Foundation, Sidney Farber Cancer Institute, and Joint Center for Radiation Therapy (CHMC-CCRF, SFCI, JCRT) from January 1, 1956 to December 31, 1976. Of these 20, 16 had simultaneous and 4 had metachronous disease on presentation. All patients were treated with surgery, radiation and chemotherapy. Of the 16 patients with simultaneous disease, 10 (63%) are alive and free of disease 12+ to 175+ months post diagnosis and treatment, with median follow-up of 121 months. There were no long-term survivors in the metachronous group; all were dead of disease within 21 months from initial presentation of original tumor. With these data we relate prognosis to extent of disease and discuss a general approach to the management of bilateral Wilms' tumor

  18. Bilateral Mandibular Paramolars

    Science.gov (United States)

    Dhull, Rachita Singh; Panda, Swagatika; Acharya, Sonu; Yadav, Shweta; Mohanty, Gatha

    2014-01-01

    ABSTRACT Supernumerary tooth is a developmental anomaly and has been argued to arise from multiple etiologies. These teeth may remain embedded in the alveolar bone or can erupt into the oral cavity. They can cause a variety of complications in the develo­ping dentition. Supernumerary teeth can present in various forms and in any region of the mandible or maxilla, but have a predisposition for the anterior maxilla. Here is the presentation of a case of unusual location of supernumerary teeth located in between mandibular first and second molar region bilaterally. How to cite this article: Dhull KS, Dhull RS, Panda S, Acharya S, Yadav S, Mohanty G. Bilateral Mandibular Paramolars. Int J Clin Pediatr Dent 2014;7(1):40-42. PMID:25206236

  19. Bilateral chronic subdural hematoma

    DEFF Research Database (Denmark)

    Andersen-Ranberg, Nina Christine; Rom Poulsen, Frantz; Bergholt, Bo

    2017-01-01

    OBJECTIVE Bilateral chronic subdural hematoma (bCSDH) is a common neurosurgical condition frequently associated with the need for retreatment. The reason for the high rate of retreatment has not been thoroughly investigated. Thus, the authors focused on determining which independent predictors...... are associated with the retreatment of bCSDH with a focus on surgical laterality. METHODS In a national database of CSDHs (Danish Chronic Subdural Hematoma Study) the authors retrospectively identified all bCSDHs treated in the 4 Danish neurosurgical departments over the 3-year period from 2010 to 2012...... that a separated hematoma density and the absence of postoperative drainage were independent predictors of retreatment. CONCLUSIONS In bCSDHs bilateral surgical intervention significantly lowers the risk of retreatment compared with unilateral intervention and should be considered when choosing a surgical...

  20. Synchronous, bilateral tonsillar carcinomas

    DEFF Research Database (Denmark)

    Saber, Camelia Nami; Grønhøj, Christian; Jensen, David Hebbelstrup

    2017-01-01

    -based, consecutive cohort of OPSCCs. METHODS: We identified all patients diagnosed with tonsillar squamous cell carcinoma (TSCC) in eastern Denmark during a 15-year period to detect the incidence of synchronous BiTSCCs. The tumours were assessed for p16Ink4a expression, the presence of HPV DNA and HPV genotypes....... Furthermore, we systematically reviewed the literature examining BiTSCCs. RESULTS: Of the total of 1119 TSCCs diagnosed in eastern Denmark from 2000 to 2014, we identified 12 BiTSCCs, nine of which initially presented as a cancer of unknown primary (CUP) in the neck. Nine cases were bilaterally HPV16 positive...... (HPV16+), while two cases were HPV16+ in one tonsil and respectively, HPV33 and HPV35 positive in the contralateral tonsil. One case was bilaterally HPV-negative. We also identified an increase in the incidence of BiTSCCs after 2012 when histological examination of the entire tonsil tissue became...

  1. Two-Step Resonance-Enhanced Desorption Laser Mass Spectrometry for In Situ Analysis of Organic-Rich Environments

    Science.gov (United States)

    Getty, S. A.; Grubisic, A.; Uckert, K.; Li, X.; Cornish, T.; Cook, J. E.; Brinckerhoff, W. B.

    2016-01-01

    A wide diversity of planetary surfaces in the solar system represent high priority targets for in situ compositional and contextual analysis as part of future missions. The planned mission portfolio will inform our knowledge of the chemistry at play on Mars, icy moons, comets, and primitive asteroids, which can lead to advances in our understanding of the interplay between inorganic and organic building blocks that led to the evolution of habitable environments on Earth and beyond. In many of these environments, the presence of water or aqueously altered mineralogy is an important indicator of habitable environments that are present or may have been present in the past. As a result, the search for complex organic chemistry that may imply the presence of a feedstock, if not an inventory of biosignatures, is naturally aligned with targeted analyses of water-rich surface materials. Here we describe the two-step laser mass spectrometry (L2MS) analytical technique that has seen broad application in the study of organics in meteoritic samples, now demonstrated to be compatible with an in situ investigation with technique improvements to target high priority planetary environments as part of a future scientific payload. An ultraviolet (UV) pulsed laser is used in previous and current embodiments of laser desorption/ionization mass spectrometry (LDMS) to produce ionized species traceable to the mineral and organic composition of a planetary surface sample. L2MS, an advanced technique in laser mass spectrometry, is selective to the aromatic organic fraction of a complex sample, which can provide additional sensitivity and confidence in the detection of specific compound structures. Use of a compact two-step laser mass spectrometer prototype has been previously reported to provide specificity to key aromatic species, such as PAHs, nucleobases, and certain amino acids. Recent improvements in this technique have focused on the interaction between the mineral matrix and the

  2. Highly effective, regiospecific reduction of chalcone by cyanobacteria leads to the formation of dihydrochalcone: two steps towards natural sweetness.

    Science.gov (United States)

    Żyszka, Beata; Anioł, Mirosław; Lipok, Jacek

    2017-08-04

    Chalcones are the biogenetic precursors of all known flavonoids, which play an essential role in various metabolic processes in photosynthesizing organisms. The use of whole cyanobacteria cells in a two-step, light-catalysed regioselective bio-reduction of chalcone, leading to the formation of the corresponding dihydrochalcone, is reported. The prokaryotic microalgae cyanobacteria are known to produce phenolic compounds, including flavonoids, as natural components of cells. It seems logical that organisms producing such compounds possess a suitable "enzymatic apparatus" to carry out their biotransformation. Therefore, determination of the ability of whole cells of selected cyanobacteria to carry out biocatalytic transformations of chalcone, the biogenetic precursor of all known flavonoids, was the aim of our study. Chalcone was found to be converted to dihydrochalcone by all examined cyanobacterial strains; however, the effectiveness of this process depends on the strain with biotransformation yields ranging from 3% to >99%. The most effective biocatalysts are Anabaena laxa, Aphanizomenon klebahnii, Nodularia moravica, Synechocystis aquatilis (>99% yield) and Merismopedia glauca (92% yield). The strains Anabaena sp. and Chroococcus minutus transformed chalcone in more than one way, forming a few products; however, dihydrochalcone was the dominant product. The course of biotransformation shed light on the pathway of chalcone conversion, indicating that the process proceeds through the intermediate cis-chalcone. The scaled-up process, conducted on a preparative scale and by using a mini-pilot photobioreactor, fully confirmed the high effectiveness of this bioconversion. Moreover, in the case of the mini-pilot photobioreactor batch cultures, the optimization of culturing conditions allowed the shortening of the process conducted by A. klebahnii by 50% (from 8 to 4 days), maintaining its >99% yield. This is the first report related to the use of whole cells of

  3. The formation of FHA coating on biodegradable Mg-Zn-Zr alloy using a two-step chemical treatment method

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, S.T.; Zhang, J.; Shun, S.Z. [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin (China); Chen, M.F., E-mail: mfchentj@126.com [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin (China); Tianjin Key Laboratory of Display Materials and Photoelectric Device, Tianjin University of Technology , Tianjin (China)

    2016-12-01

    Highlights: • Use a two-step chemical treatment method for formation of FHA coating on biodegradable Mg-Zn-Zr alloy;. • We reported the formation mechanism of FHA coating on Mg-Zn-Zr alloy and achieved optimum properties;. • The MgF{sub 2} coating and FHA coating provide effective protection for the Mg alloy substrate and the FHA coating showed better corrosion resistance. - Abstract: To improve the corrosion resistance of the biomedical magnesium alloy, a two-step chemical treatment method has been employed to prepare an FHA coating on the alloy surface. Prior to forming an FHA layer, the samples of Mg-3 wt% Zn-0.5 wt% Zr alloy were soaked in HF with concentration of 20% (v/v) at 37 °C temperature for 2 h, and were then placed into an aqueous solution with 0.1 mol/L Ca(NO{sub 3}).4H{sub 2}O and 0.06 mol/L NH{sub 4}H{sub 2}PO{sub 4} at 90 °C to prepare the Ca-P coating. The concentrations of Mg{sup 2+}, F{sup −} ions, and pH variation with immersing time in the solution were investigated to explore the growth mechanism of FHA. The surface morphologies and compositions of the coatings were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The results showed that the alloy surface treated with acid formed a layer of MgF{sub 2} nanoparticles with a thickness of 0.7 μm. The corrosion resistance of coatings in SBF solution was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results showed that the substrate with FHA coating had good corrosion resistance. After immersing into the calcium phosphate solution, some small spherical particles were first formed on the surface; these then cover the surface completely after 20 min. Some clusters consisting of needle-like crystal were observed in the spherical particles covering the surface, and the Ca/P ratio of the needle-like crystal was 1.46, clearly growing along the c axis preferred orientation growth. After

  4. Results and complications of percutaneous pelvic osteotomy and intertrochanteric varus shortening osteotomy in 54 consecutively operated GMFCS level IV and V cerebral palsy patients.

    Science.gov (United States)

    Canavese, Federico; Marengo, Lorenza; de Coulon, Geraldo

    2017-05-01

    This retrospective study evaluated mid-to-long-term outcome of a minimally invasive percutaneous pelvic osteotomy (PPO) approach combined with varus derotational shortening osteotomy (VDRSO) and soft tissue release in children with severe CP. A retrospective review was performed of all patients presenting with a diagnosis of CP with hip subluxation or dislocation treated surgically by simultaneous soft tissue release, VDRSO, and PPO between 2002 and 2015. Eligible patients included those with a diagnosis of spastic quadriplegia or CP GMFCS level IV or V with unilateral or bilateral hip subluxation or dislocation and surgical treatment of the deformity by simultaneous soft tissue release, VDRSO and PPO. All anterior-posterior (AP) radiographs of the pelvis were reviewed and Reimers migration percentage (MP) and acetabular angle (AA) were measured. In total, 54 children and adolescents (34 boys, 20 girls) with CP GMFCS level IV and V were treated during study period: 38 (70.4%) classified GMFCS level IV and 16 (29.6%) classified GMFCS level V. A total of 64 consecutive hips underwent simultaneous PPO associated with VDRSO. Overall, at the time of chart and radiograph review, mean age was 9.1 ± 3.3 years (range 4-16.5) and mean follow-up was 43.9 ± 19.5 months (range 3-72). Mean migration percentage improved from 66.8 ± 19.8% (range 33-100) preoperatively to 8.1 ± 16.5% (range 0-70) at last follow-up. Mean acetabular angle improved from 32.7° ± 7.1° (range 20-50) preoperatively to 14° ± 6.7° (range 0-27) at last follow-up. Only one case of bone graft dislodgment was observed. We did not observe any cases of avascular necrosis of the femoral head. All operated hips were pain free at the time of last follow-up. PPO through a less invasive surgical approach offers a valuable alternative to standard techniques as it gives similar outcome but with less muscle stripping and less time in surgery. III.

  5. Treatment of Hip Dysplasia in a Dog after a Failed Triple Pelvic Osteotomy with a Zurich Cementless Total Hip Replacement

    Directory of Open Access Journals (Sweden)

    SY Heo and H.B Lee*

    2013-07-01

    Full Text Available An Alaskan Malamute (2-year-old, castrated male, 41kg was referred with bilateral hind limb lameness. The dog had a history of a bilateral triple pelvic osteotomy (TPO to correct hip dysplasia one year previously, a surgery that was unsuccessful. On physical examination, pain and crepitus were noted in both hip joints. There was hip joint subluxation and mild degenerative changes bilaterally seen by radiograph. A Zurich cementless total hip replacement (ZCTHR was planned for the right hind limb. After a craniolateral approach, an acetabular cup and a cementless femoral stem were implanted. The femoral head was placed in the femoral stem, and the prosthetic joint was then reduced. At a 9 month postoperative checkup, there was no pain on palpation or manipulation of the right pelvic limb, and the range of motion was within normal limits. On radiological examination, there was no implant loosening. The ZCTHR can thus be applied in a failed TPO patient as a revision surgery.

  6. Posterior trochanteric osteotomy in acetabular fractures for 32 cases.

    Science.gov (United States)

    Niu, Yunfei; An, Xiaofei; Xu, Shuogui; Wu, Dajiang; Zhang, Chuncai; Li, Ming

    2014-11-01

    The aim of this study is to explore the method and clinical outcome of posterior trochanteric osteotomy in acetabular fractures. From January 2000 to January 2008, 32 cases of acetabular fractures involving the dome of acetabulum underwent posterior trochanteric osteotomy for a better exposure and internal fixation with acetabular tridimensional memory fixation system. 28 cases (16 men and 12 women, mean age 39.9 years, range 16-73 years) were followed up with an average of 48.9 months (range of 19-95 months) and four were lost during follow up. Of 28 cases, 19 were fresh fractures and 9 were old fractures. The reduction was evaluated with Matta criteria. Clinical evaluation was based on modified Merle d'Aubigne and Postel scoring. Motor strength of the abductors was evaluated according to the Medical Research Council grading system. Ectopic ossification was classified according to Brooker criteria. Anatomical reduction was achieved in 17 cases and satisfied reduction in 10 patients. Poor reduction happened in an old fracture. All acetabular fractures got a direct bone union and no displacement and deep infection occurred. All osteotomies healed within 3.5 months without any nonunion, proximal migration of the greater trochanter, loosing or broken of instrumentation, and deep infection. Two superficial infections were healed with a regular dressing. Two patients underwent removal of implants from greater trochanter because of irritation. The strength of the abductors was of Grade 3/5 in two patients, Grade 4/5 in five patients, and normal in the rest. Clinical scoring was excellent to good in 84 %. Ectopic ossification occurred in five patients, grade 1 in two patients, grade 2 in two, and grade 3 in one. But function of hip joint was not seriously affected. Posterior trochanteric osteotomy can provide an adequate exposure of the dome of acetabulum without the associated complications like nonunion, proximal replacement, and weak of the abductors which often occur

  7. Postoperative dysesthesia in lumbar three-column resection osteotomies.

    Science.gov (United States)

    Zhang, Zhengfeng; Wang, Honggang; Zheng, Wenjie

    2016-08-01

    Three-column lumbar spinal resection osteotomies including pedicle subtraction osteotomy (PSO), vertebral column resection (VCR), and total en bloc spondylectomy (TES) can potentially lead to dorsal root ganglion (DRG) injury which may cause postoperative dysesthesia (POD). The purpose of retrospective study was to describe the uncommon complication of POD in lumbar spinal resection osteotomies. Between January 2009 and December 2013, 64 patients were treated with lumbar three-column spinal resection osteotomies (PSO, n = 31; VCR, n = 29; TES, n = 4) in investigator group. POD was defined as dysesthetic pain or burning dysesthesia at a proper DRG innervated region, whether spontaneous or evoked. Non-steroidal antiinflammatory drugs, central none-opioid analgesic agent, neuropathic pain drugs and/or intervertebral foramen block were selectively used to treat POD. There were 5 cases of POD (5/64, 7.8 %), which consisted of 1 patient in PSO (1/31, 3.2 %), 3 patients in PVCR (3/29, 10.3 %), and 1 patient in TES (1/4, 25 %). After the treatment by drugs administration plus DRG block, all patients presented pain relief with duration from 8 to 38 days. A gradual pain moving to distal end of a proper DRG innervated region was found as the beginning of end. Although POD is a unique and rare complication and maybe misdiagnosed as nerve root injury in lumbar spinal resection osteotomies, combination drug therapy and DRG block have an effective result of pain relief. The appearance of a gradual pain moving to distal end of a proper DRG innervated region during recovering may be used as a sign for the good prognosis.

  8. A new heat transfer analysis in machining based on two steps of 3D finite element modelling and experimental validation

    Science.gov (United States)

    Haddag, B.; Kagnaya, T.; Nouari, M.; Cutard, T.

    2013-01-01

    Modelling machining operations allows estimating cutting parameters which are difficult to obtain experimentally and in particular, include quantities characterizing the tool-workpiece interface. Temperature is one of these quantities which has an impact on the tool wear, thus its estimation is important. This study deals with a new modelling strategy, based on two steps of calculation, for analysis of the heat transfer into the cutting tool. Unlike the classical methods, considering only the cutting tool with application of an approximate heat flux at the cutting face, estimated from experimental data (e.g. measured cutting force, cutting power), the proposed approach consists of two successive 3D Finite Element calculations and fully independent on the experimental measurements; only the definition of the behaviour of the tool-workpiece couple is necessary. The first one is a 3D thermomechanical modelling of the chip formation process, which allows estimating cutting forces, chip morphology and its flow direction. The second calculation is a 3D thermal modelling of the heat diffusion into the cutting tool, by using an adequate thermal loading (applied uniform or non-uniform heat flux). This loading is estimated using some quantities obtained from the first step calculation, such as contact pressure, sliding velocity distributions and contact area. Comparisons in one hand between experimental data and the first calculation and at the other hand between measured temperatures with embedded thermocouples and the second calculation show a good agreement in terms of cutting forces, chip morphology and cutting temperature.

  9. A two-step optimization strategy for 2nd generation ethanol production using softwood hemicellulosic hydrolysate as fermentation substrate.

    Science.gov (United States)

    Boboescu, Iulian-Zoltan; Gélinas, Malorie; Beigbeder, Jean-Baptiste; Lavoie, Jean-Michel

    2017-11-01

    Ethanol production using waste biomass represents a very attractive approach. However, there are considerable challenges preventing a wide distribution of these novel technologies. Thus, a fractional-factorial screening of process variables and Saccharomyces cerevisiae yeast inoculum conditions was performed using a synthetic fermentation media. Subsequently, a response-surface methodology was developed for maximizing ethanol yields using a hemicellulosic solution generated through the chemical hydrolysis of steam treatment broth obtained from residual softwood biomass. In addition, nutrient supplementation using starch-based ethanol production by-products was investigated. An ethanol yield of 74.27% of the theoretical maximum was observed for an initial concentration of 65.17g/L total monomeric sugars. The two-step experimental strategy used in this work represents the first successful attempt to developed and use a model to make predictions regarding the optimal ethanol production using both softwood feedstock residues as well as 1st generation ethanol production by-products. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Two-step biocatalytic process using lipase and whole cell catalysts for biodiesel production from unrefined jatropha oil.

    Science.gov (United States)

    Zhou, Gui-xiong; Chen, Guan-yi; Yan, Bei-bei

    2015-10-01

    To avoid lipase deactivation by methanol in the enzymatic transesterification process, a two-step biocatalytic process for biodiesel production from unrefined jatropha oil was developed. Unrefined jatropha oil was first hydrolyzed to free fatty acids (FFAs) by the commercial enzyme Candida rugosa lipase. The maximum yield achieved of FFAs 90.3% at 40 °C, water/oil ratio 0.75:1 (v/v), lipase content 2% (w/w) after 8 h reaction. After hydrolysis, the FFAs were separated and converted to biodiesel by using Rhizopus oryzae IFO4697 cells immobilized within biomass support particles as a whole-cell biocatalyst. Molecular sieves (3 Å) were added to the esterification reaction mixture to remove the byproduct water. The maximum fatty acid methyl ester yield reached 88.6% at 35 °C, molar ratio of methanol to FFAs 1.2:1, molecular sieves (3 Å) content 60% (w/w) after 42 h. In addition, both C. rugosa lipase and R. oryzae whole cell catalyst in the process showed excellent reusability, retaining 89 and 79% yields, respectively, even after six batches of reactions. This novel process, combining the advantages of enzyme and whole cell catalysts, saved the consumption of commercial enzyme and avoid enzyme deactivation by methanol.

  11. Spatial accessibility of primary health care utilising the two step floating catchment area method: an assessment of recent improvements

    Directory of Open Access Journals (Sweden)

    McGrail Matthew R

    2012-11-01

    Full Text Available Abstract Background The two step floating catchment area (2SFCA method has emerged in the last decade as a key measure of spatial accessibility, particularly in its application to primary health care access. Many recent ‘improvements’ to the original 2SFCA method have been developed, which generally either account for distance-decay within a catchment or enable the usage of variable catchment sizes. This paper evaluates the effectiveness of various proposed methods within these two improvement groups. Moreover, its assessment focuses on how well these improvements operate within and between rural and metropolitan populations over large geographical regions. Results Demonstrating these improvements to the whole state of Victoria, Australia, this paper presents the first comparison between continuous and zonal (step decay functions and specifically their effect within both rural and metropolitan populations. Especially in metropolitan populations, the application of either type of distance-decay function is shown to be problematic by itself. Its inclusion necessitates the addition of a variable catchment size function which can enable the 2SFCA method to dynamically define more appropriate catchments which align with actual health service supply and utilisation. Conclusion This study assesses recent ‘improvements’ to the 2SFCA when applied over large geographic regions of both large and small populations. Its findings demonstrate the necessary combination of both a distance-decay function and variable catchment size function in order for the 2SFCA to appropriately measure healthcare access across all geographical regions.

  12. On-line two-step stacking in capillary zone electrophoresis for the preconcentration of strychnine and brucine.

    Science.gov (United States)

    Yang, Xiumin; Zhang, Shuaihua; Wang, Juntao; Wang, Chun; Wang, Zhi

    2014-03-03

    An on-line sample preconcentration method by two-step stacking i.e., sweeping and micelle to solvent stacking, in capillary zone electrophoresis (CZE) has been developed for the determination of strychnine and brucine in traditional Chinese herbal medicines. After experimental optimizations, the best separation was achieved by using 75 mM phosphate buffer (pH 2.5) with 30% methanol (v/v). Compared with normal CZE injection, 51- and 38-fold improvement in concentration sensitivity was achieved for strychnine and brucine, respectively. The calibration curve was linear in the range of 0.1-5.0 μg mL(-1) for both strychnine and brucine, with the correlation coefficients of 0.9998 and 0.9997, respectively. The limits of detection (S/N=3) for both alkaloids were 0.01 μg mL(-1). The inter-day (n=8) and intra-day (n=5) reproducibilities expressed as the relative standard deviations for corrected peak area were less than 9.5%. The method was applied to determine strychnine and brucine in two Chinese herbal medicines, with recoveries ranging from 94.2% to 105.4%. The results indicated that the method is simple, rapid, reliable, and can be applied to determine strychnos alkaloids in traditional Chinese herbal medicines. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. A two-step approach for fluidized bed granulation in pharmaceutical processing: Assessing different models for design and control.

    Science.gov (United States)

    Ming, Liangshan; Li, Zhe; Wu, Fei; Du, Ruofei; Feng, Yi

    2017-01-01

    Various modeling techniques were used to understand fluidized bed granulation using a two-step approach. First, Plackett-Burman design (PBD) was used to identify the high-risk factors. Then, Box-Behnken design (BBD) was used to analyze and optimize those high-risk factors. The relationship between the high-risk input variables (inlet air temperature X1, binder solution rate X3, and binder-to-powder ratio X5) and quality attributes (flowability Y1, temperature Y2, moisture content Y3, aggregation index Y4, and compactability Y5) of the process was investigated using response surface model (RSM), partial least squares method (PLS) and artificial neural network of multilayer perceptron (MLP). The morphological study of the granules was also investigated using a scanning electron microscope. The results showed that X1, X3, and X5 significantly affected the properties of granule. The RSM, PLS and MLP models were found to be useful statistical analysis tools for a better mechanistic understanding of granulation. The statistical analysis results showed that the RSM model had a better ability to fit the quality attributes of granules compared to the PLS and MLP models. Understanding the effect of process parameters on granule properties provides the basis for modulating the granulation parameters and optimizing the product performance at the early development stage of pharmaceutical products.

  14. A two-step approach for fluidized bed granulation in pharmaceutical processing: Assessing different models for design and control.

    Directory of Open Access Journals (Sweden)

    Liangshan Ming

    Full Text Available Various modeling techniques were used to understand fluidized bed granulation using a two-step approach. First, Plackett-Burman design (PBD was used to identify the high-risk factors. Then, Box-Behnken design (BBD was used to analyze and optimize those high-risk factors. The relationship between the high-risk input variables (inlet air temperature X1, binder solution rate X3, and binder-to-powder ratio X5 and quality attributes (flowability Y1, temperature Y2, moisture content Y3, aggregation index Y4, and compactability Y5 of the process was investigated using response surface model (RSM, partial least squares method (PLS and artificial neural network of multilayer perceptron (MLP. The morphological study of the granules was also investigated using a scanning electron microscope. The results showed that X1, X3, and X5 significantly affected the properties of granule. The RSM, PLS and MLP models were found to be useful statistical analysis tools for a better mechanistic understanding of granulation. The statistical analysis results showed that the RSM model had a better ability to fit the quality attributes of granules compared to the PLS and MLP models. Understanding the effect of process parameters on granule properties provides the basis for modulating the granulation parameters and optimizing the product performance at the early development stage of pharmaceutical products.

  15. Cryopreservation of gametophytes of Laminaria japonica (Phaeophyta) using encapsulation-dehydration with two-step cooling method

    Science.gov (United States)

    Zhang, Quansheng; Cong, Yizhou; Qu, Shancun; Luo, Shiju; Yang, Guanpin

    2008-02-01

    Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10°C and under continuous irradiance of 30 μmol m-2 s-1 for 3 weeks were encapsulated in calcium alginate beads. The beads were dehydrated in 0.4 molL-1 sucrose prepared with seawater for 6 h, desiccated in an incubator set at 10°C and 70% relative humidity for 4 h, pre-frozen at either -40°C or -60°C for 30 min, and stored in liquid nitrogen for >24 h. As high as 43% of survival rate was observed when gametophytes were thawed by placing the beads in 40°C seawater and re-hydrated in 0.05 molL-1 citrate sodium prepared using 30‰ NaCl 7 d later. More cells of male gametophytes survived the whole procedure in comparison with female gametophytes. The cells of gametophytes surviving the preservation were able to grow asexually and produce morphologically normal sporophytes.

  16. The Security Analysis of Two-Step Quantum Direct Communication Protocol in Collective-Rotation Noise Channel

    International Nuclear Information System (INIS)

    Li Jian; Sun Feng-Qi; Pan Ze-Shi; Nie Jin-Rui; Chen Yan-Hua; Yuan Kai-Guo

    2015-01-01

    To analyze the security of two-step quantum direct communication protocol (QDCP) by using Einstein–Podolsky–Rosen pair proposed by Deng et al. [Phys. Rev. A 68 (2003) 042317] in collective-rotation noise channel, an excellent model of noise analysis is proposed. In the security analysis, the method of the entropy theory is introduced, and is compared with QDCP, an error rate point Q 0 (M : (Q 0 , 1.0)) is given. In different noise levels, if Eve wants to obtain the same amount of information, the error rate Q is distinguishable. The larger the noise level ϵ is, the larger the error rate Q is. When the noise level ϵ is lower than 11%, the high error rate is 0.153 without eavesdropping. Lastly, the security of the proposed protocol is discussed. It turns out that the quantum channel will be safe when Q < 0.153. Similarly, if error rate Q > 0.153 = Q 0 , eavesdropping information I > 1, which means that there exist eavesdroppers in the quantum channel, and the quantum channel will not be safe anymore. (paper)

  17. Degree of conversion of two-step etch-and-rinse adhesives: In situ micro-Raman analysis.

    Science.gov (United States)

    Navarra, Chiara Ottavia; Breschi, Lorenzo; Turco, Gianluca; Diolosà, Marina; Fontanive, Luca; Manzoli, Lucia; Di Lenarda, Roberto; Cadenaro, Milena

    2012-09-01

    DC of three commercial two-step etch-and-rinse adhesives across the dentine-adhesive interface was investigated using micro-Raman spectroscopy. The hypothesis tested was that no difference in DC would exist among the adhesives tested. Adper Scotchbond 1XT (3M ESPE), Prime&Bond NT (Dentsply DeTrey), and Ambar (FGM) were applied on human dentine disks (n=9). Composite increments of 2mm were then applied on the adhesive surface. Raman spectra were collected along the dentine-adhesive interface. The relative intensities of the peaks associated with the mineral (PO(4)(3-) at 960cm(-1)) and the adhesive (CC at 1640cm(-1); phenyl CC at 1610cm(-1)) were used to identify the adhesive within the hybrid layer and calculate its DC. Adper Scotchbond 1XT and Ambar showed similar DC (79±7% and 77±7%, respectively), while a lower DC was found for Prime&Bond NT (70±7%; pAmbar performed significantly better than Prime&Bond NT. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. On the Possibility of Ill-Conditioned Covariance Matrices in the First-Order Two-Step Estimator

    Science.gov (United States)

    Garrison, James L.; Axelrod, Penina; Kasdin, N. Jeremy

    1997-01-01

    The first-order two-step nonlinear estimator, when applied to a problem of orbital navigation, is found to occasionally produce first step covariance matrices with very low eigenvalues at certain trajectory points. This anomaly is the result of the linear approximation to the first step covariance propagation. The study of this anomaly begins with expressing the propagation of the first and second step covariance matrices in terms of a single matrix. This matrix is shown to have a rank equal to the difference between the number of first step states and the number of second step states. Furthermore, under some simplifying assumptions, it is found that the basis of the column space of this matrix remains fixed once the filter has removed the large initial state error. A test matrix containing the basis of this column space and the partial derivative matrix relating first and second step states is derived. This square test matrix, which has dimensions equal to the number of first step states, numerically drops rank at the same locations that the first step covariance does. It is formulated in terms of a set of constant vectors (the basis) and a matrix which can be computed from a reference trajectory (the partial derivative matrix). A simple example problem involving dynamics which are described by two states and a range measurement illustrate the cause of this anomaly and the application of the aforementioned numerical test in more detail.

  19. Enhancing recombinant interleukin-6 production yield by fermentation optimization, two-step denaturing, and one-step purification.

    Science.gov (United States)

    Ahmed, Nadeem; Abbas, Rabbia; Khan, Mohsin Ahmad; Bashir, Hamid; Tahir, Saad; Zafar, Ahmad Usman

    2017-08-22

    Interleukin-6 a pleiotropic cytokine involved in a wide range of biological activities. So the large-scale production of biologically active recombinant human interleukin-6 is important for its structural and functional studies. Here, we report an optimized method for shake flask fermentation and a simplified high-yield purification procedure for the recombinant interleukin-6. This high-yield expression method not only involves the optimization of the fermentation condition but also the single step purification method as well as a two-step denaturing and one-step refolding process. This approach replaces the more conventional procedure of protein solubilization and refolding. Through applying these strategies, the final cell density and overall product yield of the recombinant human interleukin-6 were obtained as 20.4 g as cell biomass and 150 mg as purified active protein from the I-L of the culture. The purified protein was characterized by HPLC and SDS-PAGE. The results of the current work demonstrate that the described method may be used to develop the process for industrial-scale production of the biologically active recombinant interleukin-6 protein. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

  20. A simple and accurate two-step long DNA sequences synthesis strategy to improve heterologous gene expression in pichia.

    Directory of Open Access Journals (Sweden)

    Jiang-Ke Yang

    Full Text Available In vitro gene chemical synthesis is a powerful tool to improve the expression of gene in heterologous system. In this study, a two-step gene synthesis strategy that combines an assembly PCR and an overlap extension PCR (AOE was developed. In this strategy, the chemically synthesized oligonucleotides were assembled into several 200-500 bp fragments with 20-25 bp overlap at each end by assembly PCR, and then an overlap extension PCR was conducted to assemble all these fragments into a full length DNA sequence. Using this method, we de novo designed and optimized the codon of Rhizopus oryzae lipase gene ROL (810 bp and Aspergillus niger phytase gene phyA (1404 bp. Compared with the original ROL gene and phyA gene, the codon-optimized genes expressed at a significantly higher level in yeasts after methanol induction. We believe this AOE method to be of special interest as it is simple, accurate and has no limitation with respect to the size of the gene to be synthesized. Combined with de novo design, this method allows the rapid synthesis of a gene optimized for expression in the system of choice and production of sufficient biological material for molecular characterization and biotechnological application.

  1. Improving the Physical Realism and Structural Accuracy of Protein Models by a Two-Step Atomic-Level Energy Minimization

    Science.gov (United States)

    Xu, Dong; Zhang, Yang

    2011-01-01

    Most protein structural prediction algorithms assemble structures as reduced models that represent amino acids by a reduced number of atoms to speed up the conformational search. Building accurate full-atom models from these reduced models is a necessary step toward a detailed function analysis. However, it is difficult to ensure that the atomic models retain the desired global topology while maintaining a sound local atomic geometry because the reduced models often have unphysical local distortions. To address this issue, we developed a new program, called ModRefiner, to construct and refine protein structures from Cα traces based on a two-step, atomic-level energy minimization. The main-chain structures are first constructed from initial Cα traces and the side-chain rotamers are then refined together with the backbone atoms with the use of a composite physics- and knowledge-based force field. We tested the method by performing an atomic structure refinement of 261 proteins with the initial models constructed from both ab initio and template-based structure assemblies. Compared with other state-of-art programs, ModRefiner shows improvements in both global and local structures, which have more accurate side-chain positions, better hydrogen-bonding networks, and fewer atomic overlaps. ModRefiner is freely available at http://zhanglab.ccmb.med.umich.edu/ModRefiner. PMID:22098752

  2. A Two-Step A/D Conversion and Column Self-Calibration Technique for Low Noise CMOS Image Sensors

    Directory of Open Access Journals (Sweden)

    Jaeyoung Bae

    2014-07-01

    Full Text Available In this paper, a 120 frames per second (fps low noise CMOS Image Sensor (CIS based on a Two-Step Single Slope ADC (TS SS ADC and column self-calibration technique is proposed. The TS SS ADC is suitable for high speed video systems because its conversion speed is much faster (by more than 10 times than that of the Single Slope ADC (SS ADC. However, there exist some mismatching errors between the coarse block and the fine block due to the 2-step operation of the TS SS ADC. In general, this makes it difficult to implement the TS SS ADC beyond a 10-bit resolution. In order to improve such errors, a new 4-input comparator is discussed and a high resolution TS SS ADC is proposed. Further, a feedback circuit that enables column self-calibration to reduce the Fixed Pattern Noise (FPN is also described. The proposed chip has been fabricated with 0.13 μm Samsung CIS technology and the chip satisfies the VGA resolution. The pixel is based on the 4-TR Active Pixel Sensor (APS. The high frame rate of 120 fps is achieved at the VGA resolution. The measured FPN is 0.38 LSB, and measured dynamic range is about 64.6 dB.

  3. Long-Time Plasma Membrane Imaging Based on a Two-Step Synergistic Cell Surface Modification Strategy.

    Science.gov (United States)

    Jia, Hao-Ran; Wang, Hong-Yin; Yu, Zhi-Wu; Chen, Zhan; Wu, Fu-Gen

    2016-03-16

    Long-time stable plasma membrane imaging is difficult due to the fast cellular internalization of fluorescent dyes and the quick detachment of the dyes from the membrane. In this study, we developed a two-step synergistic cell surface modification and labeling strategy to realize long-time plasma membrane imaging. Initially, a multisite plasma membrane anchoring reagent, glycol chitosan-10% PEG2000 cholesterol-10% biotin (abbreviated as "GC-Chol-Biotin"), was incubated with cells to modify the plasma membranes with biotin groups with the assistance of the membrane anchoring ability of cholesterol moieties. Fluorescein isothiocyanate (FITC)-conjugated avidin was then introduced to achieve the fluorescence-labeled plasma membranes based on the supramolecular recognition between biotin and avidin. This strategy achieved stable plasma membrane imaging for up to 8 h without substantial internalization of the dyes, and avoided the quick fluorescence loss caused by the detachment of dyes from plasma membranes. We have also demonstrated that the imaging performance of our staining strategy far surpassed that of current commercial plasma membrane imaging reagents such as DiD and CellMask. Furthermore, the photodynamic damage of plasma membranes caused by a photosensitizer, Chlorin e6 (Ce6), was tracked in real time for 5 h during continuous laser irradiation. Plasma membrane behaviors including cell shrinkage, membrane blebbing, and plasma membrane vesiculation could be dynamically recorded. Therefore, the imaging strategy developed in this work may provide a novel platform to investigate plasma membrane behaviors over a relatively long time period.

  4. Two-step source tracing strategy of Yersinia pestis and its historical epidemiology in a specific region.

    Directory of Open Access Journals (Sweden)

    Yanfeng Yan

    Full Text Available Source tracing of pathogens is critical for the control and prevention of infectious diseases. Genome sequencing by high throughput technologies is currently feasible and popular, leading to the burst of deciphered bacterial genome sequences. Utilizing the flooding genomic data for source tracing of pathogens in outbreaks is promising, and challenging as well. Here, we employed Yersinia pestis genomes from a plague outbreak at Xinghai county of China in 2009 as an example, to develop a simple two-step strategy for rapid source tracing of the outbreak. The first step was to define the phylogenetic position of the outbreak strains in a whole species tree, and the next step was to provide a detailed relationship across the outbreak strains and their suspected relatives. Through this strategy, we observed that the Xinghai plague outbreak was caused by Y. pestis that circulated in the local plague focus, where the majority of historical plague epidemics in the Qinghai-Tibet Plateau may originate from. The analytical strategy developed here will be of great help in fighting against the outbreaks of emerging infectious diseases, by pinpointing the source of pathogens rapidly with genomic epidemiological data and microbial forensics information.

  5. THEODORE, a two-step heating system for the EC/OC determination of radiocarbon (14C) in the environment

    International Nuclear Information System (INIS)

    Szidat, S.; Jenk, T.M.; Gaeggeler, H.W.; Synal, H.-A.; Hajdas, I.; Bonani, G.; Saurer, M.

    2004-01-01

    Measurements of 14 C in the organic carbon (OC) and elemental carbon (EC) fractions, respectively, of fine aerosol particles bear the potential to apportion anthropogenic and biogenic emission sources. For this purpose, the system THEODORE (two-step heating system for the EC/OC determination of radiocarbon in the environment) was developed. In this device, OC and EC are transformed into carbon dioxide in a stream of oxygen at 340 and 650 deg. C, respectively, and reduced to filamentous carbon. This is the target material for subsequent accelerator mass spectrometry (AMS) 14 C measurements, which were performed on sub-milligram carbon samples at the PSI/ETH compact 500 kV AMS system. Quality assurance measurements of SRM 1649a, Urban Dust, yielded a fraction of modern f M in total carbon (TC) of 0.522 ± 0.018 (n=5, 95% confidence level) in agreement with reported values. The results for OC and EC are 0.70 ± 0.05 (n=3) and 0.066 ± 0.020 (n=4), respectively

  6. Novel strategy for immunomodulation: Dissolving microneedle array encapsulating thymopentin fabricated by modified two-step molding technology.

    Science.gov (United States)

    Lin, Shiqi; Cai, Bingzhen; Quan, Guilan; Peng, Tingting; Yao, Gangtao; Zhu, Chune; Wu, Qiaoli; Ran, Hao; Pan, Xin; Wu, Chuanbin

    2018-01-01

    Thymopentin (TP5) is commonly used in the treatment for autoimmune diseases, with a short plasma half-life (30s) and a long treatment period (7 days to 6 months). It is usually administrated by syringe injection, resulting in compromised patient compliance. Dissolving microneedle array (DMNA) offers a superior approach for transdermal delivery of biological macromolecules, as it allows painless penetration through the stratum corneum and generates minimal biohazardous waste after dissolving in the skin. Despite recent advances in DMNA as a novel approach for transdermal drug delivery, problem of insufficient mechanical strength remains to be solved. In this study, TP5-loaded DMNA (TP5-DMNA) was uniquely developed using a modified two-step molding technology. The higher mechanical strength was furnished by employing bovine serum albumin (BSA) as a co-material to fabricate the needles. The obtained TP5-DMNA containing BSA displayed better skin penetration and higher drug loading efficiency than that without BSA. The in vivo pharmacodynamics study demonstrated that TP5-DMNA had comparative effect on immunomodulation to intravenous injection of TP5, in terms of ameliorating the CD4+/CD8+ ratio, SOD activity and MDA value to the basal level. Only mild irritation was observed at the site of administration. These results suggest that the novel TP5-DMNA utilizing BSA provides an alternative approach for convenient and safe transdermal delivery of TP5, which is a promising administration strategy for future clinical application. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Comparison of a novel one-step percutaneous nephrolithotomy sheath with a standard two-step device.

    Science.gov (United States)

    Maynes, Lincoln J; Desai, Premal J; Zuppan, Craig W; Barker, Brent J; Zimmerman, Grenith J; Baldwin, D Duane

    2008-02-01

    Percutaneous nephrolithotomy (PCNL) is the treatment of choice for large renal calculi. The most widely used access sheath for PCNL involves two steps including placement of a high-pressure balloon catheter (HPBC) followed by advancement of a sheath over the balloon. A novel PCNL balloon/sheath combination (NSS) has been developed that allows for both dilation and sheath placement in a single step. The objective of this study was to compare the safety and efficacy of the NSS to the HPBC in a porcine model. Six farm pigs underwent placement of a standard HPBC in one kidney and the NSS on the contralateral side. We obtained access in the upper pole in 2 animals, middle pole in 2 animals, and lower pole in 2 animals. We obtained data on insertion time, difficulty of insertion, estimated blood loss (EBL), ability to visualize the collecting system, and gross and histopathologic analysis. There was no statistical difference in degree of difficulty in placing the NSS (3 easy, 3 moderate) versus HPBC device (1 easy, 5 moderate; P = 0.07), estimated blood loss (P = 0.10), or the ability to visualize the collecting system (P = 0.32). There was a significantly shorter insertion time in the NSS group compared with the HPBC group (1:37 versus 2:26 minutes, P = 0.04). This study demonstrates that the NSS is safe and effective in the porcine model. Trials in patients are currently under way.

  8. A two-step real-time PCR assay for quantitation and genotyping of human parvovirus 4.

    Science.gov (United States)

    Väisänen, E; Lahtinen, A; Eis-Hübinger, A M; Lappalainen, M; Hedman, K; Söderlund-Venermo, M

    2014-01-01

    Human parvovirus 4 (PARV4) of the family Parvoviridae was discovered in a plasma sample of a patient with an undiagnosed acute infection in 2005. Currently, three PARV4 genotypes have been identified, however, with an unknown clinical significance. Interestingly, these genotypes seem to differ in epidemiology. In Northern Europe, USA and Asia, genotypes 1 and 2 have been found to occur mainly in persons with a history of injecting drug use or other parenteral exposure. In contrast, genotype 3 appears to be endemic in sub-Saharan Africa, where it infects children and adults without such risk behaviour. In this study, a novel straightforward and cost-efficient molecular assay for both quantitation and genotyping of PARV4 DNA was developed. The two-step method first applies a single-probe pan-PARV4 qPCR for screening and quantitation of this relatively rare virus, and subsequently, only the positive samples undergo a real-time PCR-based multi-probe genotyping. The new qPCR-GT method is highly sensitive and specific regardless of the genotype, and thus being suitable for studying the clinical impact and occurrence of the different PARV4 genotypes. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Two-Step Sintering Behavior of Sol-Gel Derived Dense and Submicron-Grained YIG Ceramics

    Science.gov (United States)

    Chen, Ruoyuan; Zhou, Jijun; Zheng, Liang; Zheng, Hui; Zheng, Peng; Ying, Zhihua; Deng, Jiangxia

    2018-04-01

    In this work, dense and submicron-grain yttrium iron garnet (YIG, Y3Fe5O12) ceramics were fabricated by a two-step sintering (TSS) method using nano-size YIG powder prepared by a citrate sol-gel method. The densification, microstructure, magnetic properties and ferromagnetic resonance (FMR) linewidth of the ceramics were investigated. The sample prepared at 1300°C in T 1, 1225°C in T 2 and 18 h holding time has a density higher than 98% of the theoretical value and exhibits a homogeneous microstructure with fine grain size (0.975 μm). In addition, the saturation magnetization ( M S) of this sample reaches 27.18 emu/g. High density and small grain size can also achieve small FMR linewidth. Consequently, these results show that the sol-gel process combined with the TSS process can effectively suppress grain-boundary migration while maintaining active grain-boundary diffusion to obtain dense and fine-grained YIG ceramics with appropriate magnetic properties.

  10. Two-step production of monoamines in monoenzymatic cells in the spinal cord: a different control strategy of neurotransmitter supply?

    Directory of Open Access Journals (Sweden)

    Mengliang Zhang

    2016-01-01

    Full Text Available Monoamine neurotransmitters play an important role in the modulation of sensory, motor and autonomic functions in the spinal cord. Although traditionally it is believed that in mammalian spinal cord, monoamine neurotransmitters mainly originate from the brain, accumulating evidence indicates that especially when the spinal cord is injured, they can also be produced in the spinal cord. In this review, I will present evidence for a possible pathway for two-step synthesis of dopamine and serotonin in the spinal cord. Published data from different sources and unpublished data from my own ongoing projects indicate that monoenzymatic cells expressing aromatic L-amino acid decarboxylase (AADC, tyrosine hydroxylase (TH or tryptophan hydroxylase (TPH are present in the spinal cord and that these TH and THP cells often lie in close proximity to AADC cells. Prompted by the above evidence, I hypothesize that dopamine and serotonin could be synthesized sequentially in two monoenzymatic cells in the spinal cord via a TH-AADC and a TPH-AADC cascade respectively. The monoamines synthesized through this pathway may compensate for lost neurotransmitters following spinal cord injury and also may play specific roles in the recovery of sensory, motor and autonomic functions.

  11. Production of acetic acid by hydrothermal two-step process of vegetable wastes for use as a road deicer

    Energy Technology Data Exchange (ETDEWEB)

    Jin, F; Watanabe, Y; Kishita, A; Enomoto, H [Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579 (Japan); Kishida, H [Environmental Systems Headquarters, Environmental Research and Development Center Hitachi Zosen Corporation, Kyoto 625-8501 (Japan)], E-mail: fmjin@mail.tongji.edu.cn

    2008-07-15

    This study aimed to produce acetic acid from vegetable wastes by a new hydrothermal two-step process. A continuous flow reaction system with a maximum treatment capacity of 2 kg/h of dry biomass developed by us was used. Five kinds of vegetables of carrots, white radish, chinese cabbage, cabbage and potato were selected as the representation of vegetable wastes. First, batch experiments with the selected vegetables were performed under the condition of 300 deg. C, 1 min for the first step, and 300 deg. C, 1 min and 70% oxygen supply for the second step, which is the optimum condition for producing acetic acid in the case of using starch as test material. The highest yields of acetic acid from five vegetables were almost the same as those obtained from starch. Subsequently, similar the highest yield of acetic acid and experimental conditions from vegetables were also obtained successfully using the continuous flow reaction system. These results should be useful for developing an industrial scale process.

  12. A simple and accurate two-step long DNA sequences synthesis strategy to improve heterologous gene expression in pichia.

    Science.gov (United States)

    Yang, Jiang-Ke; Chen, Fang-Yuan; Yan, Xiang-Xiang; Miao, Li-Hong; Dai, Jiang-Hong

    2012-01-01

    In vitro gene chemical synthesis is a powerful tool to improve the expression of gene in heterologous system. In this study, a two-step gene synthesis strategy that combines an assembly PCR and an overlap extension PCR (AOE) was developed. In this strategy, the chemically synthesized oligonucleotides were assembled into several 200-500 bp fragments with 20-25 bp overlap at each end by assembly PCR, and then an overlap extension PCR was conducted to assemble all these fragments into a full length DNA sequence. Using this method, we de novo designed and optimized the codon of Rhizopus oryzae lipase gene ROL (810 bp) and Aspergillus niger phytase gene phyA (1404 bp). Compared with the original ROL gene and phyA gene, the codon-optimized genes expressed at a significantly higher level in yeasts after methanol induction. We believe this AOE method to be of special interest as it is simple, accurate and has no limitation with respect to the size of the gene to be synthesized. Combined with de novo design, this method allows the rapid synthesis of a gene optimized for expression in the system of choice and production of sufficient biological material for molecular characterization and biotechnological application.

  13. A two-step approach for fluidized bed granulation in pharmaceutical processing: Assessing different models for design and control

    Science.gov (United States)

    Ming, Liangshan; Li, Zhe; Wu, Fei; Du, Ruofei; Feng, Yi

    2017-01-01

    Various modeling techniques were used to understand fluidized bed granulation using a two-step approach. First, Plackett-Burman design (PBD) was used to identify the high-risk factors. Then, Box-Behnken design (BBD) was used to analyze and optimize those high-risk factors. The relationship between the high-risk input variables (inlet air temperature X1, binder solution rate X3, and binder-to-powder ratio X5) and quality attributes (flowability Y1, temperature Y2, moisture content Y3, aggregation index Y4, and compactability Y5) of the process was investigated using response surface model (RSM), partial least squares method (PLS) and artificial neural network of multilayer perceptron (MLP). The morphological study of the granules was also investigated using a scanning electron microscope. The results showed that X1, X3, and X5 significantly affected the properties of granule. The RSM, PLS and MLP models were found to be useful statistical analysis tools for a better mechanistic understanding of granulation. The statistical analysis results showed that the RSM model had a better ability to fit the quality attributes of granules compared to the PLS and MLP models. Understanding the effect of process parameters on granule properties provides the basis for modulating the granulation parameters and optimizing the product performance at the early development stage of pharmaceutical products. PMID:28662115

  14. Ceria-based electrospun fibers for renewable fuel production via two-step thermal redox cycles for carbon dioxide splitting.

    Science.gov (United States)

    Gibbons, William T; Venstrom, Luke J; De Smith, Robert M; Davidson, Jane H; Jackson, Gregory S

    2014-07-21

    Zirconium-doped ceria (Ce(1-x)Zr(x)O2) was synthesized through a controlled electrospinning process as a promising approach to cost-effective, sinter-resistant material structures for high-temperature, solar-driven thermochemical redox cycles. To approximate a two-step redox cycle for solar fuel production, fibrous Ce(1-x)Zr(x)O2 with relatively low levels of Zr-doping (0 production. Cycle stability of the fibrous Ce(1-x)Zr(x)O2 (with x = 0.025) was assessed for a range of conditions by measuring rates of O2 release during reduction and CO production during reoxidation and by assessing post-cycling fiber crystallite sizes and surface areas. Sintering increases with reduction temperature but occurs primarily along the fiber axes. Even after 108 redox cycles with reduction at 1400 °C and oxidation with CO2 at 800 °C, the fibers maintain their structure with surface areas of ∼0.3 m(2) g(-1), higher than those observed in the literature for other ceria-based structures operating at similarly high temperature conditions. Total CO production and peak production rate stabilize above 3.0 mL g(-1) and 13.0 mL min(-1) g(-1), respectively. The results show the potential for electrospun oxides as sinter-resistant material structures with adequate surface area to support rapid CO2 splitting in solar thermochemical redox cycles.

  15. CdS/CdSe lateral heterostructure nanobelts by a two-step physical vapor transport method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu Lee; Jung, Jae Hun; Yoon, Hyun Sik; Song, Man Suk; Bae, Se Hwan; Kim, Yong [Department of Physics, Dong-A University, Hadan-2-dong, Sahagu, Busan 604-714 (Korea, Republic of); Chen Zhigang; Zou Jin [Materials Engineering and Center of Microscopy and Microanalysis, University of Queensland, Brisbane, QLD 4072 (Australia); Joyce, Hannah J; Gao Qiang; Tan, Hark Hoe; Jagadish, Chennupati, E-mail: yongkim@dau.ac.kr [Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia)

    2010-04-09

    The two-dimensional heterostructure nanobelts with a central CdSe region and lateral CdS structures are synthesized by a two-step physical vapor transport method. The large growth rate difference between lateral CdS structures on both {+-} (0001) sides of the CdSe region is found. The growth anisotropy is discussed in terms of the polar nature of the side {+-} (0001) surfaces of CdSe. High-resolution transmission electron microscopy reveals the CdSe central region covered with non-uniform CdS layer/islands. From micro-photoluminescence measurements, a systematic blueshift of emission energy from the central CdSe region in accordance with the increase of lateral CdS growth temperature is observed. This result indicates that the intermixing rate in the CdSe region with CdS increases with the increase of lateral CdS growth temperature. In conventional CdSSe ternary nanostructures, morphology and emission wavelength were correlated parameters. However, the morphology and emission wavelength are independently controllable in the CdS/CdSe lateral heterostructure nanobelts. This structure is attractive for applications in visible optoelectronic devices.

  16. Improving the physical realism and structural accuracy of protein models by a two-step atomic-level energy minimization.

    Science.gov (United States)

    Xu, Dong; Zhang, Yang

    2011-11-16

    Most protein structural prediction algorithms assemble structures as reduced models that represent amino acids by a reduced number of atoms to speed up the conformational search. Building accurate full-atom models from these reduced models is a necessary step toward a detailed function analysis. However, it is difficult to ensure that the atomic models retain the desired global topology while maintaining a sound local atomic geometry because the reduced models often have unphysical local distortions. To address this issue, we developed a new program, called ModRefiner, to construct and refine protein structures from Cα traces based on a two-step, atomic-level energy minimization. The main-chain structures are first constructed from initial Cα traces and the side-chain rotamers are then refined together with the backbone atoms with the use of a composite physics- and knowledge-based force field. We tested the method by performing an atomic structure refinement of 261 proteins with the initial models constructed from both ab initio and template-based structure assemblies. Compared with other state-of-art programs, ModRefiner shows improvements in both global and local structures, which have more accurate side-chain positions, better hydrogen-bonding networks, and fewer atomic overlaps. ModRefiner is freely available at http://zhanglab.ccmb.med.umich.edu/ModRefiner. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  17. Prenylcoumarins in One or Two Steps by a Microwave-Promoted Tandem Claisen Rearrangement/Wittig Olefination/Cyclization Sequence.

    Science.gov (United States)

    Schultze, Christiane; Schmidt, Bernd

    2018-05-04

    The one-pot synthesis of 8-prenylcoumarins from 1,1-dimethylallylated salicylaldehydes and the stabilized ylide [(ethoxycarbonyl)methylene]triphenylphosphorane under microwave conditions was found to have a limited scope. The sequence suffers from a difficult and sometimes low-yielding synthesis of the precursors and from a competing deprenylation upon microwave irradiation. This side reaction occurs in particular with electron rich arenes with two or more alkoxy groups at adjacent positions, a prominent substitution pattern in naturally occurring 8-prenylcoumarins. Both limitations of this one-step sequence were overcome by a two-step synthesis consisting of a microwave-promoted tandem allyl ether Claisen rearrangement/Wittig olefination and a subsequent olefin cross metathesis with 2-methyl-2-butene. The cross metathesis step proceeds with a high selectivity and yields exclusively the desired prenyl, rather than the alternative crotyl substituent. Several naturally occurring 8-prenylcoumarins that were previously inaccessible have been synthesized in good overall yields along this route.

  18. The Effect of Two-Step Heat Treatment Parameters on Microstructure and Mechanical Properties of 42SiMn Steel

    Directory of Open Access Journals (Sweden)

    Ludmila Kučerová

    2017-12-01

    Full Text Available Medium-carbon steel 42SiMn (0.4C-0.6Mn-2Si-0.03Nb was used for a two-step heat treatment consisting of a soaking hold and an annealing hold at bainite transformation temperature. Various heating temperatures, cooling rates, and bainitic hold temperatures were applied to the steel to obtain microstructures typical for TRIP (Transformation Induced Plasticity steels. TRIP steels utilize the positive effects of a multiphase microstructure with retained austenite, creating a good combination of strength and total elongation and an excellent deep-drawing ability. Typical microstructures consist of ferrite, bainite, and 10–15% of retained austenite. In this work, tensile strengths in the region of 887–1063 MPa were achieved with total elongation A5mm of 26–47%, and the final microstructures contained 4–16% of retained austenite. The most suitable microstructure and the best combination of high strength and total elongation were achieved for the processing with intercritical heating temperature of 850 °C and cooling at 30 °C/s to the bainitic hold of 400 °C. Very fine pearlite persisted in the microstructures, even after applying a cooling rate of 50 °C/s, however these small areas with extremely fine laths did not prevent the retention of up to 16% of retained austenite, and high total elongation A5mm above 40% was still reached for these microstructures.

  19. Determination of the isotopic abundance of iron and nickel with two-step laser time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    Zhou Mingfei; Qin Qizong

    1996-01-01

    Two-step laser time-of-flight mass spectrometry is established to measure the isotopic abundance of iron and nickel. A pulsed Nd:YAG laser (532 nm) is used to evaporate iron and nickel atoms from a Meral alloy sample. These atoms are ionized by a Nd:YAG pumped pulsed dye laser at 300.7 nm and 303.4 nm via resonance ionization and subsequently detected by time-of-flight mass spectrometry. Arrival time distributions are obtained by varying the time delay between evaporation laser and ionization laser. Overlap of the pulsed atomic beam and the ionization laser beam is excellent with about 1% effective duty cycle, then the sensitivity of isotopic detection will be increased substantially using resonance ionization time-of-flight mass spectrometry. A one color two-photon (1 + 1) ionization scheme is employed for Fe and Ni atoms. The results show that all the measured isotopic abundances of Fe and Ni are in agreement with values published in the literature

  20. Normalized superposed epoch analysis reveals two step main phase enhancement: evidence for potential and inductive convection during intense geomagnetic events

    Science.gov (United States)

    Katus, R. M.; Liemohn, M. W.; Ridley, A. J.; Gallagher, D. L.; Zou, S.

    2011-12-01

    The relative contribution of storm-time ring current development by convection driven by either potential or inductive electric fields has remained an unresolved question in geospace research. Studies have been published supporting each side of this debate, including views that ring current build-up is entirely one or the other. This study presents new insights into the relative roles of these storm main phase processes. We perform a superposed epoch study of 141 intense storms (Dst storm dynamics compared to conventional methods. Examination of the enhanced resolution Dst reveals an inflection point consistent with two-step main phase development, which is supported by results for the southward interplanetary magnetic field and various ground-based magnetic indices. It is determined that the first step of Dst development is due to potential convective drift, during which an initial ring current is formed. The negative feedback of this hot ion population begins to limit further ring current growth. The second step of the main phase, however, is found to be dominated by substorm activity. It is hypothesized that this is necessary to achieve intense storm Dst levels because the substorm dipolarizations are effective at breaking through the negative feedback barrier of the existing inner magnetospheric hot ion pressure peak. In addition, the plasmaspheric drainage plume could be influencing dayside reconnection rates, which would then change the convective flow in the tail and the development of the ring current.