Braces

Science.gov (United States)

... wear a retainer , which is a small, hard piece of plastic with metal wires or a thin piece of plastic shaped like a mouthguard. Retainers make ... More on this topic for: Kids Word! Braces Going to the Dentist Going to the Orthodontist Taking ...

KNOWLEDGE AND MISCONCEPTIONS OF PULMONARY TUBERCULOSIS PATIENTS AT DOTS CENTRE, URBAN MEERUT.

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R Bansal

2013-06-01

Full Text Available Background: India is the second most populated country in the world; it has more new TB cases annually than any other country. In 2008, 1.98 million were estimated to have occurred in India, of whom 0.87 million were infectious cases, thus amounting to a fifth of the global burden of TB.With the entire country geographically covered under the DOTS program, research into socioeconomic impact of TB on patients and their households is crucial for providing comprehensive patient-friendly TB services and to document the benefits of DOTS. Objective: The present study was undertaken with the following objectives: (1 To determine the socio-demographic variables of registered patients for DOTS Treatment at Urban Health Training center Meerut. (2 To assess knowledge, awareness and attitude regarding Pulmonary Tuberculosis and its treatment among the patients. Materials and Methods: A cross-sectional study of 200 TB patients was done using a pre-tested semi-quantitative questionnaire in UHTC Meerut Period of Study: During 2010-2012. Results: Knowledge and awareness regarding Pulmonary Tuberculosis in patients at DOTS centre, Urban Meerut was very poor. There is a great need to educate the people about misconceptions like food and utensils as mode of transmission. BCC using the person to person contact in community , at health center and awareness campaigns are crucial in educating the ignorance seen in our field practice area. Conclusion: Poor knowledge and misconceptions concerning tuberculosis was quite concern in the patients. TB control program will remain ineffective unless myths and fears of TB patients are addressed related to causation of tuberculosis, mode of spread, and methods of prevention.

KNOWLEDGE AND MISCONCEPTIONS OF PULMONARY TUBERCULOSIS PATIENTS AT DOTS CENTRE, URBAN MEERUT.

Directory of Open Access Journals (Sweden)

R Bansal

2013-08-01

Full Text Available Background: India is the second most populated country in the world; it has more new TB cases annually than any other country. In 2008, 1.98 million were estimated to have occurred in India, of whom 0.87 million were infectious cases, thus amounting to a fifth of the global burden of TB.With the entire country geographically covered under the DOTS program, research into socioeconomic impact of TB on patients and their households is crucial for providing comprehensive patient-friendly TB services and to document the benefits of DOTS. Objective: The present study was undertaken with the following objectives: (1 To determine the socio-demographic variables of registered patients for DOTS Treatment at Urban Health Training center Meerut. (2 To assess knowledge, awareness and attitude regarding Pulmonary Tuberculosis and its treatment among the patients. Materials and Methods: A cross-sectional study of 200 TB patients was done using a pre-tested semi-quantitative questionnaire in UHTC Meerut Period of Study: During 2010-2012. Results: Knowledge and awareness regarding Pulmonary Tuberculosis in patients at DOTS centre, Urban Meerut was very poor. There is a great need to educate the people about misconceptions like food and utensils as mode of transmission. BCC using the person to person contact in community , at health center and awareness campaigns are crucial in educating the ignorance seen in our field practice area. Conclusion: Poor knowledge and misconceptions concerning tuberculosis was quite concern in the patients. TB control program will remain ineffective unless myths and fears of TB patients are addressed related to causation of tuberculosis, mode of spread, and methods of prevention.

Isothermal (vapour + liquid) equilibrium for the binary {l_brace}1,1,2,2-tetrafluoroethane (R134) + propane (R290){r_brace} and {l_brace}1,1,2,2-tetrafluoroethane (R134) + isobutane (R600a){r_brace} systems

Energy Technology Data Exchange (ETDEWEB)

Dong Xueqiang [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Gong Maoqiong, E-mail: gongmq@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Liu Junsheng [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Wu Jianfeng, E-mail: jfwu@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China)

2010-09-15

(Vapour + liquid) equilibrium (VLE) data for the binary systems of {l_brace}1,1,2,2-tetrafluoroethane (R134) + propane (R290){r_brace} and {l_brace}1,1,2,2-tetrafluoroethane (R134) + isobutane (R600a){r_brace} were measured with a recirculation method at the temperatures ranging from (263.15 to 278.15) K and (268.15 to 288.15) K, respectively. All of the data were correlated by the Peng-Robinson (PR) equation of state (EoS) with the Huron-Vidal (HV) mixing rules utilizing the non-random two-liquid (NRTL) activity coefficient model. Good agreement can be found between the experimental data and the correlated results. Azeotropic behaviour can be found at the measured temperature ranges for these two mixtures.

Effect of uniaxial strain on adatom diffusion across {l_brace}1 1 1{r_brace}-faceted step

Energy Technology Data Exchange (ETDEWEB)

Yang Jianyu, E-mail: wuliyangjianyu@yahoo.com.cn [Department of Maths and Physics, Hunan Institute of Engineering, Donghu Street, Xiangtan 411104 (China); Hu Wangyu, E-mail: Wangyuhu2001@yahoo.com.cn [Department of Applied Physics, Hunan University, Changsha 410082 (China); Tang Jianfeng [Department of Applied Physics, Hunan Agricultural University, Changsha 410128 (China)

2011-02-01

Diffusion of Pt adatom across the strained {l_brace}1 1 1{r_brace}-faceted step is studied by embedded atom method along with nudged elastic band method. For adatom on the flat (1 1 1) surface, the anisotropic diffusion behavior is found as the uniaxial strain is imposed. For the strained {l_brace}1 1 1{r_brace}-faceted step, our results show that the maximum energy barrier for adatom crossing step edge remains approximately constant as the strain varied from -1.0% to 1.0%, and there is a rise as the larger uniaxial strain is applied. The calculated energy barrier for adatom diffusion along the step edge increases with increasing tensile strain, and the slope of the straight line is small.

Anisotropy and magnetostriction as corrections for the Heisenberg model at the example of the molecule {l_brace}Ni{sub 4}Mo{sub 12}{r_brace}; Anisotropie und Magnetostriktion als Korrekturen zum Heisenberg-Modell am Beispiel des Molekuels {l_brace}Ni{sub 4}Mo{sub 12}{r_brace}

Energy Technology Data Exchange (ETDEWEB)

Brueger, Mirko

2008-07-15

In the first part of this thesis the different effects of the molecular magnetism were extensively considered and the possibility of their occurence in {l_brace}Ni{sub 4}Mo{sub 12}{r_brace} checked. In the second part of this thesis different models for the description of experimental results were presented. thereby the results of ESR, SQUIO, and high-field pulse measurements on {l_brace}Ni{sub 4}Mo{sub 12}{r_brace} are described.

New Generation Lockable Knee Brace

Science.gov (United States)

2000-01-01

A knee brace that uses Space Shuttle propulsion technology has moved a step closer to being available to help knee injury and stroke patients and may possibly benefit patients with birth defects, spinal cord injuries, and post-polio conditions. After years of hard work, inventors at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, have turned over the final design and prototype to industry partners at Horton's Orthotic Lab in Little Rock, Arkansas for further clinical testing. The device, called the Selectively Lockable Knee Brace, may mean faster, less painful rehabilitation for patients by allowing the knee to move when weight is not on the heel. Devices currently on the market lock the knee in a rigid, straight-leg position, or allow continuous free motion. The knee brace is just one example of how space technology is being used to improve the lives of people on Earth. NASA's MSFC inventors Michael Shadoan and Neill Myers are space propulsion engineers who use the same mechanisms and materials to build systems for rockets that they used to design and develop the knee brace.

Effectiveness of Chêneau brace treatment for idiopathic scoliosis: prospective study in 79 patients followed to skeletal maturity

Directory of Open Access Journals (Sweden)

Kotwicki Tomasz

2011-01-01

Full Text Available Abstract Background Progressive idiopathic scoliosis can negatively influence the development and functioning of 2-3% of adolescents, with health consequences and economic costs, placing the disease in the centre of interest of the developmental medicine. The aim of this study was to evaluate the effectiveness of Chêneau brace in the management of idiopathic scoliosis. Methods A prospective observational study according to SOSORT and SRS recommendations comprised 79 patients (58 girls and 21 boys with progressive idiopathic scoliosis, treated with Chêneau brace and physiotherapy, with initial Cobb angle between 20 and 45 degrees, no previous brace treatment, Risser 4 or more at the final evaluation and minimum one year follow-up after weaning the brace. Achieving 50° of Cobb angle was considered surgical recommendation. Results At follow-up 20 patients (25.3% improved, 18 patients (22.8% were stable, 31 patients (39.2% progressed below 50 degrees and 10 patients (12.7% progressed beyond 50 degrees (2 of these 10 patients progressed beyond 60 degrees. Progression concerned the younger and less skeletally mature patients. Conclusion Conservative treatment with Chêneau orthosis and physiotherapy was effective in halting scoliosis progression in 48.1% of patients. The results of this study suggest that bracing is effective in reducing the incidence of surgery in comparison with natural history.

Initial experience with the providence nighttime bracing in adolescent idiopathic scoliosis

DEFF Research Database (Denmark)

Quisth, Lena; Beuschau, Inge; Simony, A.

2015-01-01

Background: Since 2008 the primary non-surgical treatment of adolescent idiopathic scoliosis (AIS) in the southern part of Denmark, went from full-time bracing with Boston brace, to Providence nighttime bracing. Aim: To evaluate the effectiveness of nighttime bracing, with the Providence brace...... with the Providence nighttime brace and an acceptable 18 % failure rate. The nighttime brace is an excellent alternative to standard conservative treatment, and reduces the need for physiotherapy after brace termination. The patients tolerate the nighttime brace treatment well, and compliance within the cohort......, in AIS. Method: Patients diagnosed with AIS. With an apex from TH7 and below and with a cobb angel between 20-45 degrees. The patients were evaluated every 6 months with standing x-rays and the brace treatment was continued until two years post menarche. Cobb angle of the major curve pretreatment, in...

Nanodiamond-based nanostructures for coupling nitrogen-vacancy centres to metal nanoparticles and semiconductor quantum dots.

Science.gov (United States)

Gong, Jianxiao; Steinsultz, Nat; Ouyang, Min

2016-06-08

The ability to control the interaction between nitrogen-vacancy centres in diamond and photonic and/or broadband plasmonic nanostructures is crucial for the development of solid-state quantum devices with optimum performance. However, existing methods typically employ top-down fabrication, which restrict scalable and feasible manipulation of nitrogen-vacancy centres. Here, we develop a general bottom-up approach to fabricate an emerging class of freestanding nanodiamond-based hybrid nanostructures with external functional units of either plasmonic nanoparticles or excitonic quantum dots. Precise control of the structural parameters (including size, composition, coverage and spacing of the external functional units) is achieved, representing a pre-requisite for exploring the underlying physics. Fine tuning of the emission characteristics through structural regulation is demonstrated by performing single-particle optical studies. This study opens a rich toolbox to tailor properties of quantum emitters, which can facilitate design guidelines for devices based on nitrogen-vacancy centres that use these freestanding hybrid nanostructures as building blocks.

Dynamic extensor brace for lateral epicondylitis.

NARCIS (Netherlands)

Faes, M.C.; Akker, B. van den; Lint, J.A. de; Kooloos, J.G.M.; Hopman, M.T.E.

2006-01-01

Lateral epicondylitis (tennis elbow) is a common, often disabling ailment. Based on the failure of current therapies, a new dynamic extensor brace has been developed. In this study, the effects of application of this brace for 3 months on the most important and disabling symptoms of patients with

Providence nighttime bracing, in treatment of adolescent idiopathic scoliosis

DEFF Research Database (Denmark)

Simony, A.; Beuschau, Inge; Quisth, Lena

2015-01-01

Introduction: Since 2008 the non-surgical treatment of adolescent idiopathic scoliosis (AIS) in the southern part of Denmark, went from full-time bracing with Boston brace, to Providence night-time bracing. Methods: Since 2008, skeletally immature patients diagnosed with AIS and a primary curve w...

Eccentric bracing of steel frames in seismic design

International Nuclear Information System (INIS)

Popov, E.P.; Manheim, D.

1981-01-01

The general concepts of designing eccentrically braced steel frames are discussed. A number of possible bracing configurations are pointed out which are suitable for this type of framing. The necessity for considering the collapse mechanism for the selected frame is brought out, and the need for considering the ductility demands for the critical elements is indicated. The need for web stiffness along the critical beam elements (links), and the necessity for lateral bracing at the potential plastic hinges is emphasized. Properly designed eccentrically braced frames provide good drift control for moderate earthquakes, and good ductility for extreme earthquakes. Experience gained in practice attests to the practicality and economy of this kind of framing. The major disadvantage of properly designed eccentrically braced frames lies in the fact that high local distortions may occur during a severe earthquake requiring repair. However, such severe distortions should attenuate rapidly from the damaged areas. (orig./HP)

49 CFR 195.208 - Welding of supports and braces.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Welding of supports and braces. 195.208 Section 195.208 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS... HAZARDOUS LIQUIDS BY PIPELINE Construction § 195.208 Welding of supports and braces. Supports or braces may...

Three dimensional analysis of brace biomechanical efficacy for patients with AIS

DEFF Research Database (Denmark)

Lebel, David E; Al-Aubaidi, Zaid; Shin, Eyun-Jung

2013-01-01

Corrective three dimensional (3D) effect of different braces is debatable. We evaluated differences in in-brace radiographic correction comparing a custom thoracic-lumbo-sacral-orthosis (TLSO) (T) brace to a Chêneau type TLSO (C) brace using 3D EOS reconstruction technology. Our primary research ...

Corrective Bracing for Severe Idiopathic Scoliosis in Adolescence: Influence of Brace on Trunk Morphology

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Edyta Kinel

2012-01-01

Full Text Available Aim. The aim of the work was to study whether wearing a corrective brace by adolescent girls with severe idiopathic scoliosis can influence external shape of the trunk. Methods. Comparison of clinical deformity of two groups of girls matched for age and Cobb angle: group (1 of 23 girls, aged 14.9±1.3 years, Cobb angle 55.0°±6.8°, who refused surgical treatment and have been wearing Chêneau brace for more than 6 months, compared with group (2 of 22 girls, aged 14.1±1.8 years, Cobb angle 59.7°±14.6° never treated with corrective bracing. Clinical deformity was assessed with the Bunnell scoliometer (angle of trunk rotation ATR and surface topography (posterior trunk symmetry index POTSI and Hump Sum HS. Results. The ATR in the primary curvature was 11.9°±3.4° (5°–18° in group 1 versus 15.1°±5.6° (6°–25° in group 2 (P=0.027. The HS was 16.8°±3.8 versus 19.2°±4.6, respectively, P=0.07. The POTSI value did not differ between groups. Conclusion. Girls with Cobb angle above 45 degrees, who have been subjected to brace treatment, revealed smaller clinical deformity of their back comparing to nontreated girls having similar radiological curvatures.

MINIMUM BRACING STIFFNESS FOR MULTI-COLUMN SYSTEMS: THEORY

OpenAIRE

ARISTIZÁBAL-OCHOA, J. DARÍO

2011-01-01

A method that determines the minimum bracing stiffness required by a multi-column elastic system to achieve non-sway buckling conditions is proposed. Equations that evaluate the required minimum stiffness of the lateral and torsional bracings and the corresponding “braced" critical buckling load for each column of the story level are derived using the modified stability functions. The following effects are included: 1) the types of end connections (rigid, semirigid, and simple); 2) the bluepr...

Different coordination modes for disulfoxides towards diorganotin(IV) dichlorides. X-ray crystal structures of 1,2-cis-bis-(phenylsulfinyl)ethene (rac-,cis-cbpse) and adducts [{l_brace}Ph{sub 2}SnCl{sub 2}(meso-bpse){r_brace}{sub n}] and [{l_brace}n-Bu{sub 2}SnCl{sub 2}(pdtd){r_brace}{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Sousa, Gerimario F. de [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Quimica], e-mail: gfreitas@unb.br; Ellena, Javier [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Fisica; Malta, Valeria R.S. [Universidade Federal de Alagoas (UFAL), Maceio, AL (Brazil). Dept. de Quimica e Biotecnologia; Ardisson, Jose D. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Lab. de Fisica Aplicada

2009-07-01

The reactions of meso-1,2-bis(phenylsulfinyl)ethane (meso-bpse) with Ph{sub 2}SnCl{sub 2}, 2-phenyl-1,3-dithiane trans-1-trans-3-dioxide (pdtd) with n-Bu{sub 2}SnCl{sub 2} and 1,2-cis-bis-(phenylsulfinyl) ethene (rac-,cis-cbpse) with Ph{sub 2}SnCl{sub 2}, in 1:1 molar ratio, yielded [{l_brace}Ph{sub 2}SnCl{sub 2}(meso-bpse){r_brace}{sub n}], [{l_brace}n-Bu{sub 2}SnCl{sub 2}(pdtd){r_brace}{sub 2}] and [{l_brace}Ph{sub 2}SnCl{sub 2}(rac,cis-cbpse){r_brace}x] (x = 2 or n), respectively. All adducts were studied by IR, Moessbauer and {sup 119}Sn NMR spectroscopic methods, elemental analysis and single crystal X-ray diffractometry. The X-ray crystal structure of [{l_brace}Ph{sub 2}SnCl{sub 2}(meso-bpse){r_brace}{sub n}] revealed the occurrence of infinite chains in which the tin(IV) atoms appear in a distorted octahedral geometry with Cl atoms in cis and Ph groups in trans positions. The X-ray crystal structure of [{l_brace}n-Bu{sub 2}SnCl{sub 2}(pdtd){r_brace}{sub 2}] revealed discrete centrosymmetric dimeric species in which the tin(IV) atoms possess a distorted octahedral geometry with bridging disulfoxides in cis and n-butyl moieties in trans positions. The spectroscopic data indicated that the adduct containing the rac,cis-cbpse ligand can be dimeric or polymeric. The X-ray structural analysis of the free rac-,cis-cbpse sulfoxide revealed that the crystals belong to the C2/c space group. (author)

Development and preliminary validation of Brace Questionnaire (BrQ: a new instrument for measuring quality of life of brace treated scoliotics

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Gkoltsiou Konstantina

2006-05-01

Full Text Available Abstract Background The quality of life among children with idiopathic scoliosis during their adolescence has been reported to be affected by the brace itself. However, a controversy exists whether brace treated scoliotics experience a poor quality of life, thus there is a need for the development of a brace-oriented instrument, as the now-existing questionnaires that are commonly used, such as the SRS -22, take into consideration the effects of both the conservative and the surgical treatment on quality of life of scoliotic children. The aim of the present study is to assess the validity and reliability of Brace Questionnaire (BrQ, a new instrument for measuring quality of life of scoliotic adolescents who are treated conservatively with a brace. Material-method Methodology of development involved literature review, patient and health care professionals' in-depth interviews and content validity analysis on patients. A validation study was performed on 28 brace treated scoliotic children aged between 9 and 18 years old. BrQ was assessed for the following psychometric properties: item convergent validity, floor and ceiling effects, internal consistency reliability, clinical validity and responsiveness to change. Results BrQ is self administrated and developmentally appropriate for ages 9 to 18 years old and is consisted of 34 Likert-scale items associated with eight domains: general health perception, physical functioning, emotional functioning, self esteem and aesthetics, vitality, school activity, bodily pain and social functioning of scoliotic children treated conservatively with a brace. The subscales of these eight dimensions can be combined to produce a total score. Higher scores mean a better quality of life. An item convergent validity ≥ 0.40 was satisfied by all items in the present study. A satisfactory internal consistency reliability for the BrQ was recorded (Cronbach's alpha coefficient was 0.82. There were no floor or ceiling

A prospective randomized controlled study on the treatment outcome of SpineCor brace versus rigid brace for adolescent idiopathic scoliosis with follow-up according to the SRS standardized criteria.

Science.gov (United States)

Guo, Jing; Lam, Tsz Ping; Wong, Man Sang; Ng, Bobby Kin Wah; Lee, Kwong Man; Liu, King Lok; Hung, Lik Hang; Lau, Ajax Hong Yin; Sin, Sai Wing; Kwok, Wing Kwan; Yu, Fiona Wai Ping; Qiu, Yong; Cheng, Jack Chun Yiu

2014-12-01

SpineCor is a relatively innovative brace for non-operative treatment of adolescent idiopathic scoliosis (AIS). However, the effectiveness of SpineCor still remains controversial. The objective of the current study was to compare the treatment outcomes of SpineCor brace with that of rigid brace following the standardized Scoliosis Research Society (SRS) criteria on AIS brace study. Females subjects with AIS and aged 10-14 were randomly allocated into two groups undergoing treatment of SpineCor (S Group, n = 20) or rigid brace (R Group, n = 18). During SpineCor treatment, patients who had curve progression of >5° would be required to switch to rigid brace treatment. The effectiveness of the two brace treatments was assessed using the SRS standardized criteria. Before skeletal maturity, 7 (35.0%) patients in the S Group and 1 (5.6%) patient in the R Group had curve progression >5° (P = 0.026). At skeletal maturity, 5 of the 7 (71.4%) patients who failed with SpineCor bracing showed control from further progression by changing to rigid bracing. At the latest follow-up with a mean duration of 45.1 months after skeletally maturity, 29.4% of patients who were successfully treated by rigid brace showed further curve progression beyond skeletal maturity, versus 38.5% of patients in the SpineCor group (P > 0.05). For both groups, the primary curves were slightly improved at the time of brace weaning, but additionally increased at the latest follow-up, with a rate of 1.5° per year for post-maturity progression. Curve progression rate was found to be significantly higher in the SpineCor group when compared with the rigid brace group. Changing to rigid bracing could control further curve progression for majority of patients who previously failed with SpineCor bracing. For both SpineCor and rigid brace treatments, 30-40% of patients who were originally successfully treated by bracing would exhibit further curve progression beyond skeletal maturity. The post

Scoliosis brace design: influence of visual aesthetics on user acceptance and compliance.

Science.gov (United States)

Law, Derry; Cheung, Mei-Chun; Yip, Joanne; Yick, Kit-Lun; Wong, Christina

2017-06-01

Adolescent idiopathic scoliosis is a common condition found in adolescents. A rigid brace is often prescribed as the treatment for this spinal deformity, which negatively affects user compliance due to the discomfort caused by the brace, and the psychological distress resulting from its appearance. However, the latter, which is the impact of visual aesthetics, has not been thoroughly studied for scoliosis braces. Therefore, a qualitative study with in-depth interviews has been carried out with 10 participants who have a Cobb angle of 20°-30° to determine the impact of visual aesthetics on user acceptance and compliance towards the brace. It is found that co-designing with patients on the aesthetic aspects of the surface design of the brace increases the level of user compliance and induces positive user perception. Therefore, aesthetic preferences need to be taken into consideration in the design process of braces. Practitioner Summary: The impact of visual aesthetics on user acceptance and compliance towards a rigid brace for scoliosis is investigated. The findings indicate that an aesthetically pleasing brace and the involvement of patients in the design process of the brace are important for increasing user compliance and addressing psychological issues during treatment.

Cyclic Testing of Steel Chevron Braces with Vertically Slotted Beam Connection

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Rozlyn K. Bubela

2010-07-01

Full Text Available Experimental tests were performed to study the seismic behavior and performance of modified steel chevron braced frame systems, which incorporate a vertical slotted connection (VSC detail between the top of the braces and the floor beam above. The VSC detail is intended to prevent vertical load transfer to the beam and limit brace forces to the compressive resistance of the members. Full-scale quasi-static cyclic tests were performed on two specimens with hollow tube braces, with one specimen having the braces filled with concrete. Both frames exhibited stable, predictable behavior under cyclic loading. The VSC detail provided free vertical movement of the brace assembly during both tests. However, its flexibility created a moderate reduction in the overall lateral stiffness of the frame. The concrete-filled tube specimen sustained higher peak loads, demonstrated greater residual strength and dissipated more energy than the hollow tube specimen due to the partial inhibition of local buckling by the concrete core. It was found that the VSC chevron braced frame system is a suitable concept for use in buildings in high-risk seismic zones.

Workflow of CAD / CAM Scoliosis Brace Adjustment in Preparation Using 3D Printing.

Science.gov (United States)

Weiss, Hans-Rudolf; Tournavitis, Nicos; Nan, Xiaofeng; Borysov, Maksym; Paul, Lothar

2017-01-01

High correction bracing is the most effective conservative treatment for patients with scoliosis during growth. Still today braces for the treatment of scoliosis are made by casting patients while computer aided design (CAD) and computer aided manufacturing (CAM) is available with all possibilities to standardize pattern specific brace treatment and improve wearing comfort. CAD / CAM brace production mainly relies on carving a polyurethane foam model which is the basis for vacuuming a polyethylene (PE) or polypropylene (PP) brace. Purpose of this short communication is to describe the workflow currently used and to outline future requirements with respect to 3D printing technology. Description of the steps of virtual brace adjustment as available today are content of this paper as well as an outline of the great potential there is for the future 3D printing technology. For 3D printing of scoliosis braces it is necessary to establish easy to use software plug-ins in order to allow adding 3D printing technology to the current workflow of virtual CAD / CAM brace adjustment. Textures and structures can be added to the brace models at certain well defined locations offering the potential of more wearing comfort without losing in-brace correction. Advances have to be made in the field of CAD / CAM software tools with respect to design and generation of individually structured brace models based on currently well established and standardized scoliosis brace libraries.

A new dual bracing system for improving the seismic behavior of steel structures

International Nuclear Information System (INIS)

Kari, A; Ghassemieh, M; Abolmaali, S A

2011-01-01

Shape memory alloy braces and buckling restrained braces have been shown to exhibit favorable energy dissipating characteristics in steel structures. However, buckling restrained braces are unable to recover their original shape after unloading and consequently experience large residual inter-story drifts after the earthquake, which leads to large permanent deformations in the structure. On the other hand, shape memory braces possess the recentering feature which enables them to recover their original shape. Nevertheless, compared to buckling restrained braced frames, the shape memory bracing frame usually experiences larger maximum inter-story drifts during the earthquake. This paper presents the results of a numerical study conducted to investigate the benefit of using the combination of buckling restrained braces and shape memory braces (dual bracing) in one structure, for the new design as well as retrofitting purposes. The superelastic model of shape memory alloy and plasticity model of steel are incorporated into the nonlinear finite element program particularly developed for this research. Results revealed that, with the proper configuration, both aims, namely minimizing both residual and maximum inter-story drifts, can be attained

Quadra-quantum Dots and Related Patterns of Quantum Dot Molecules:

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Somsak Panyakeow

2010-10-01

Full Text Available Abstract Laterally close-packed quantum dots (QDs called quantum dot molecules (QDMs are grown by modified molecular beam epitaxy (MBE. Quantum dots could be aligned and cross hatched. Quantum rings (QRs created from quantum dot transformation during thin or partial capping are used as templates for the formations of bi-quantum dot molecules (Bi-QDMs and quantum dot rings (QDRs. Preferable quantum dot nanostructure for quantum computation based on quantum dot cellular automata (QCA is laterally close-packed quantum dot molecules having four quantum dots at the corners of square configuration. These four quantum dot sets are called quadra-quantum dots (QQDs. Aligned quadra-quantum dots with two electron confinements work like a wire for digital information transmission by Coulomb repulsion force, which is fast and consumes little power. Combination of quadra-quantum dots in line and their cross-over works as logic gates and memory bits. Molecular Beam Epitaxial growth technique called ‘‘Droplet Epitaxy” has been developed for several quantum nanostructures such as quantum rings and quantum dot rings. Quantum rings are prepared by using 20 ML In-Ga (15:85 droplets deposited on a GaAs substrate at 390°C with a droplet growth rate of 1ML/s. Arsenic flux (7–8×10-6Torr is then exposed for InGaAs crystallization at 200°C for 5 min. During droplet epitaxy at a high droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic strain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar quantum rings as templates, four quantum dots situated at the corners of a square shape are regrown. Two of these four quantum dots are aligned either or , which are preferable crystallographic directions of quantum dot alignment in general.

Treatment of osteoarthritis of the knee with bracing: a scoping review

Directory of Open Access Journals (Sweden)

Steven Phillips

2016-06-01

Full Text Available Knee osteoarthritis is a leading cause of disability around the world. Knee bracing provides a conservative management option for symptom relief. A variety of different bracing types, manufacturers and products are currently available on the market. The goal of this study is to examine the current state of the literature regarding the treatment of knee osteoarthritis with unloader bracing, specifically examining the representation of specific brace types, manufacturers and models within the literature. A scoping review technique was used because of its ability to evaluate research activity within an area of study and identify gaps within the literature. A thorough search of the MEDLINE database was conducted for articles where a knee brace model was identified, and we identified characteristics of the studies to evaluate important information about the body of literature related to knee bracing for the treatment of osteoarthritis. Fifty eligible studies were identified. The majority of studies have been published in the United States, and a large increase in the number of publications in this field was seen between 2010-2014. The most prominent study type was prospective comparative studies (44%, however there is a lack of randomized controlled trials (6% within the literature. The most prominent hinge type within the literature is the dual hinge push brace, followed by the single hinge pull. While a large increase in the number of studies evaluating the treatment of knee osteoarthritis with bracing has occurred in the past 5 years, there is a lack of high quality studies evaluating the efficacy of the technique, as well as a lack of studies comparing bracing types and models.

Quadra-Quantum Dots and Related Patterns of Quantum Dot Molecules: Basic Nanostructures for Quantum Dot Cellular Automata Application

Directory of Open Access Journals (Sweden)

Somsak Panyakeow

2010-10-01

Full Text Available Laterally close-packed quantum dots (QDs called quantum dot molecules (QDMs are grown by modified molecular beam epitaxy (MBE. Quantum dots could be aligned and cross hatched. Quantum rings (QRs created from quantum dot transformation during thin or partial capping are used as templates for the formations of bi-quantum dot molecules (Bi-QDMs and quantum dot rings (QDRs. Preferable quantum dot nanostructure for quantum computation based on quantum dot cellular automata (QCA is laterally close-packed quantum dot molecules having four quantum dots at the corners of square configuration. These four quantum dot sets are called quadra-quantum dots (QQDs. Aligned quadra-quantum dots with two electron confinements work like a wire for digital information transmission by Coulomb repulsion force, which is fast and consumes little power. Combination of quadra-quantum dots in line and their cross-over works as logic gates and memory bits. Molecular Beam Epitaxial growth technique called 'Droplet Epitaxy' has been developed for several quantum nanostructures such as quantum rings and quantum dot rings. Quantum rings are prepared by using 20 ML In-Ga (15:85 droplets deposited on a GaAs substrate at 390'C with a droplet growth rate of 1ML/s. Arsenic flux (7'8'10-6Torr is then exposed for InGaAs crystallization at 200'C for 5 min. During droplet epitaxy at a high droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic strain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar quantum rings as templates, four quantum dots situated at the corners of a square shape are regrown. Two of these four quantum dots are aligned either or, which are preferable crystallographic directions of quantum dot alignment in general.

Quantifying the Lateral Bracing Provided by Standing Steam Roof Systems

OpenAIRE

Sorensen, Taylor J.

2016-01-01

One of the major challenges of engineering is finding the proper balance between economical and safe. Currently engineers at Nucor Corporation have ignored the additional lateral bracing provided by standing seam roofing systems to joists because of the lack of methods available to quantify the amount of bracing provided. Based on the results of testing performed herein, this bracing is significant, potentially resulting in excessively conservative designs and unnecessary costs. This proje...

Cervical bracing practices after degenerative cervical surgery: a survey of cervical spine research society members.

Science.gov (United States)

Lunardini, David J; Krag, Martin H; Mauser, Nathan S; Lee, Joon Y; Donaldson, William H; Kang, James D

2018-05-21

Context: Prior studies have shown common use of post-operative bracing, despite advances in modern day instrumentation rigidity and little evidence of brace effectiveness. To document current practice patterns of brace use after degenerative cervical spine surgeries among members of the Cervical Spine Research Society (CSRS), to evaluate trends, and to identify areas of further study. A questionnaire survey METHODS: A 10 question survey was sent to members of the Cervical Spine Research Society to document current routine bracing practices after various common degenerative cervical spine surgical scenarios, including fusion and non-fusion procedures. The overall bracing rate was 67%. This included 8.4% who used a hard collar in each scenario. Twenty-two percent of surgeons never used a hard collar, while 34% never used a soft collar, and 3.6% (3 respondents) did not use a brace in any surgical scenario. Bracing frequency for specific surgical scenarios varied from 39% after foraminotomy to 88% after multi-level corpectomy with anterior & posterior fixation. After one, two and three level anterior cervical discectomy & fusion (ACDF), bracing rates were 58%, 65% and 76% for an average of 3.3, 4.3 and 5.3 weeks, respectively. After single level corpectomy, 77% braced for an average of 6.2 weeks. After laminectomy and fusion, 72% braced for an average of 5.4 weeks. Significant variation persists among surgeons on the type and length of post-operative brace usage after cervical spine surgeries. Overall rates of bracing have not changed significantly with time. Given the lack evidence in the literature to support bracing, reconsidering use of a brace after certain surgeries may be warranted. Copyright © 2018. Published by Elsevier Inc.

Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

Science.gov (United States)

Kamanli, Mehmet; Unal, Alptug

2017-10-01

After devastating earthquakes in recent years, strengthening of reinforced concrete buildings became an important research topic. Reinforced concrete buildings can be strengthened by steel braced frames. These steel braced frames may be made of concentrically or eccentrically indicated in Turkish Earthquake Code 2007. In this study pushover analysis of the 1/3 scaled 1 reinforced concrete frame and 1/3 scaled 4 strengthened reinforced concrete frames with internal eccentric steel braced frames were conducted by SAP2000 program. According to the results of the analyses conducted, load-displacement curves of the specimens were compared and evaluated. Adding eccentric steel braces to the bare frame decreased the story drift, and significantly increased strength, stiffness and energy dissipation capacity. In this strengthening method lateral load carrying capacity, stiffness and dissipated energy of the structure can be increased.

Prophylactic Bracing Has No Effect on Lower Extremity Alignment or Functional Performance.

Science.gov (United States)

Hueber, Garrett A; Hall, Emily A; Sage, Brad W; Docherty, Carrie L

2017-07-01

Prophylactic ankle bracing is commonly used during physical activity. Understanding how bracing affects body mechanics is critically important when discussing both injury prevention and sport performance. The purpose is to determine if ankle bracing affects lower extremity mechanics during the Landing Error Scoring System test (LESS) and Sage Sway Index (SSI). Thirty physically active participants volunteered for this study. Participants completed the LESS and SSI in both a braced and unsupported conditions. Total errors were recorded for the LESS. Total errors and time (seconds) were recorded for the SSI. The Wilcoxon signed-rank test was utilized to evaluate any differences between the brace conditions for each dependent variable. A priori alpha level was set at pWilcoxon signed-rank test yielded no significant difference between the braced and unsupported conditions for the LESS (Z=-0.35, p=0.72), SSI time (Z=-0.36, p=0.72), or SSI Errors (Z=-0.37, p=0.71). Ankle braces had no effect on subjective clinical assessments of lower extremity alignment or postural stability. Utilization of a prophylactic support at the ankle did not substantially alter the proximal components of the lower kinetic chain. © Georg Thieme Verlag KG Stuttgart · New York.

The Basics of Braces

Science.gov (United States)

... wear a specially molded retainer — a small, hard piece of plastic with metal wires or a thin piece of plastic shaped like a mouthguard. Retainers keep ... Teeth Keeping Your Child's Teeth Healthy Word! Braces Going to the Dentist The Reality of Retainers What ...

Electronic and structural characterizations of unreconstructed {l_brace}0001{r_brace} surfaces and the growth of graphene overlayers

Energy Technology Data Exchange (ETDEWEB)

Emtsev, Konstantin

2009-06-03

The present work is focused on the characterization of the clean unreconstructed SiC{l_brace}0001{r_brace} surfaces and the growth of graphene overlayers thereon. Electronic properties of SiC surfaces and their interfaces with graphene and few layer graphene films were investigated by means of angle resolved photoelectron spectroscopy, X-ray photoelectron spectroscopy and low energy electron diffraction. Structural characterizations of the epitaxial graphene films grown on SiC were carried out by atomic force microscopy and low energy electron microscopy. Supplementary data was obtained by scanning tunneling microscopy. (orig.)

Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

Directory of Open Access Journals (Sweden)

Kamanli Mehmet

2017-01-01

Full Text Available After devastating earthquakes in recent years, strengthening of reinforced concrete buildings became an important research topic. Reinforced concrete buildings can be strengthened by steel braced frames. These steel braced frames may be made of concentrically or eccentrically indicated in Turkish Earthquake Code 2007. In this study pushover analysis of the 1/3 scaled 1 reinforced concrete frame and 1/3 scaled 4 strengthened reinforced concrete frames with internal eccentric steel braced frames were conducted by SAP2000 program. According to the results of the analyses conducted, load-displacement curves of the specimens were compared and evaluated. Adding eccentric steel braces to the bare frame decreased the story drift, and significantly increased strength, stiffness and energy dissipation capacity. In this strengthening method lateral load carrying capacity, stiffness and dissipated energy of the structure can be increased.

Prospective study of 158 adult scoliosis treated by a bivalve polyethylene overlapping brace and reviewed at least 5 years after brace fitting

Directory of Open Access Journals (Sweden)

Jean Claude de Mauroy

2016-10-01

Full Text Available Abstract Background The conservative orthopaedic treatment of adult scoliosis is very disappointing. In a series of 144 patients; only 25 % (33 cases were monitored at 2 years of treatment. (Papadopoulos 2013. Thereby the literature typically focuses on a small number of patients, which limits the usefulness and relevance of its results. The brace effect on pain has been systematically described, but there is no publication on the effect of treatment on the Cobb angle and main clinical parameters. Methods From a prospective database started in 1998, we selected all 158 consecutive patients effectively treated conservatively with the Lyon management treatment and controlled five years after brace fitting. Lyon management includes a lordosing bivalve polyethylene overlapping brace in association with specific physiotherapy. The brace can either be short with anterior support under the chest or long with sterno-clavicular support when there is a high thoracic kyphosis. Results 1. For the rate of scoliosis controlled after 5 years, the follow-up was 24 % of the 661 patients accepting the treatment. Pain is almost the main reason for the medical consultation, generally correlating with an increase of the scoliotic angulation. 2. The descriptive data can be superimposed on general group with age (m=56 years, SD=13 but initial Cobb angulation is significantly higher (m=40°, SD=17. Ratio Female/Male=0.91. Generally, the scoliosis is stabilized at (m=39.74 °, SD=19.40, 8 years after the beginning of the treatment. 38 improvements of more than 5°= 24 %; 88 stable = 56 %; 32 worsening of more than 5° = 20 % The rib hump is improved of by 3 mm, (modelling effect of the brace. The occipital axis is improved by more than 6 mm. But the T1 plumb line distance is worsening by 7 mm (most braces are short without sterno-clavicular support. Conclusions For the first time, the number of records and follow up after 8 years allows to study the

Bracing of the Reconstructed and Osteoarthritic Knee during High Dynamic Load Tasks.

Science.gov (United States)

Hart, Harvi F; Crossley, Kay M; Collins, Natalie J; Ackland, David C

2017-06-01

Lateral compartment osteoarthritis accompanied by abnormal knee biomechanics is frequently reported in individuals with knee osteoarthritis after anterior cruciate ligament reconstruction (ACLR). The aim of this study was to evaluate changes in knee biomechanics produced by an adjusted and unadjusted varus knee brace during high dynamic loading activities in individuals with lateral knee osteoarthritis after ACLR and valgus malalignment. Nineteen participants who had undergone ACLR 5 to 20 yr previously and had symptomatic and radiographic lateral knee osteoarthritis with valgus malalignment were assessed. Quantitative motion analysis experiments were conducted during hopping, stair ascent, and descent under three test conditions: (i) no brace, (ii) unadjusted brace with sagittal plane support and neutral frontal plane alignment, and (iii) adjusted brace with sagittal plane support and varus realignment (valgus to neutral). Sagittal, frontal, and transverse plane knee kinematics, external joint moment, and angular impulse data were calculated. Relative to an unbraced knee, braced conditions significantly increased knee flexion and adduction angles during hopping (P = 0.003 and P = 0.005; respectively), stair ascent (P = 0.003 and P stair ascent (P = 0.008) and flexion moments during stair descent (P = 0.006). There were no significant differences between the adjusted and the unadjusted brace conditions (P > 0.05). A knee brace, with or without varus alignment, can modulate knee kinematics and external joint moments during hopping, stairs ascent, and descent in individuals with predominant lateral knee osteoarthritis after ACLR. Longer-term use of a brace may have implications in slowing osteoarthritis progression.

Evaluation of Long Leg Braces in Regard to Biomechanical, Clinival and Technical Orthopedic\\'s Fundamentals

Directory of Open Access Journals (Sweden)

Reza Vahhab-Kashani

2006-01-01

Full Text Available Objective: In some clients, for lower extremity, long leg brace, is prescribed. Then it will be fabricated bye orthotist and worn by patient. According to clinical principles, the brace should be as fit as possible with limb form. Also, an individual, walks and sits with his or her brace. Brace functions around joint motion axis. Quality and exact place of movement is define by biomechanical principles. Therefore, brace should be adapted with biochemical principles of the limb. Materials & Methods: A brace is made up several components which are assembled through acceptable technical orthopaedic methods and this procedure should be done without omission or neglect. If orthotist has enough scientific knowledge and observes all details, he or she will fabricate a perfect brace. We considered fabricated long leg brace according to this principle to meet study objectives while answering some question of study, we will disguss on the finding of our assessment. Also, we examine some possible deviations with accured by unsuitable fabrication, more over we suggest that some failur in designing procedure which leads to such deviation material and methods: In this descriptive analytic cross sectional study, long leg braces of 193 clients who were selected by random stratified sampling method, were evaluated by a previously designed questionare . Results: A. By assessment of 7 variables, it was revealed that 28.86% of manufactured braces, was not adapted with defined fundamentals, biomechanically. B. By evaluation of 9 variables, it was made known that 30 % of produced braces was not adapted with established fabricating fundamentals of lower limb braces clinically. C. By examination of 23 variables it was find out that 25.4% of fabricated braces, it was observed, which has some failures by attention to defined fabricating technical orthopaedic fundamentals. Conclusion: All the details, fabrication and design procedures should be carefully observed and

Reforming the Belgian market for orthotic braces: what can we learn from the international experience?

Science.gov (United States)

Simoens, Steven; De Coster, Sandra; Moldenaers, Ingrid; Guillaume, Paul; Depoorter, Antony; Van den Steen, Dirk; Van de Sande, Stefaan; Debruyne, Hans; Ramaekers, Dirk; Lona, Murielle

2008-05-01

This article aims to review regulation governing outpatient orthotic braces (neck, wrist and knee braces) in France, the Netherlands and Sweden with a view to reforming the Belgian market. Information about the regulatory framework was derived from an analysis of legal texts and a survey completed by national experts. Strategies to keep down prices include public procurement in Sweden, maximum prices in France, and exclusion of expensive braces from reimbursement in the Netherlands. Reimbursement is linked to a medical indication or a chronic condition in France, the Netherlands and Sweden. To gain reimbursement, the cost-effectiveness of orthotic braces needs to be demonstrated in France and the Netherlands. Orthotic braces tend to be initially prescribed by a specialist physician and distributed by orthotists, medical equipment shops and/or community pharmacies. Extensive government intervention exists in the outpatient orthotic brace market in the countries studied. Our recommendations to reform the Belgian market for prefabricated orthotic braces are to separate reimbursement for service provision from reimbursement for braces; to set prices by means of a tendering process or an international price comparison; and to make reimbursement conditional on effectiveness and cost-effectiveness of braces.

A new method of MR total spine imaging for showing the brace effect in scoliosis

Energy Technology Data Exchange (ETDEWEB)

Schmitz, A.; Kandyba, J.; Koenig, R.; Jaeger, U.E.; Gieseke, J.; Schmitt, O. [Univ. of Bonn (Germany)

2001-07-01

Bracing is a method of early, nonsurgical treatment for scoliosis, but a hypokyphotic effect on the thoracic spine is reported. We developed a magnetic resonance tomography (MR) procedure presenting an image of the whole spine in the coronal and sagittal planes (MR total spine imaging), and studied the brace effect, using this technique. We examined 26 female patients with idiopathic scoliosis treated with a Cheneau brace (mean age, 13.2 years; mean duration of brace treatment at the time of investigation, 1.5 years). The MR examinations were performed with the patient in the supine position with and without the brace in direct sequence. As measured on the coronal MR images, the thoracic curve was corrected, on average, from 29 deg to 22 deg (mean correction, 24%). There was a slight reduction in the sagittal Cobb angle measured between T4 and T12 (mean sagittal Cobb angle without brace, 14 deg ; with brace, 12 deg), which was still a significant change. MR total spine imaging could be a useful tool for studying the brace effect in scoliosis in two planes. Using this technique, we found reduced sagittal Cobb angles for the thoracic kyphosis with brace. Because there is no radiation exposure, the MR procedure has a potential use in the monitoring of brace treatment. (author)

Clinical practice guidelines for rest orthosis, knee sleeves, and unloading knee braces in knee osteoarthritis.

Science.gov (United States)

Beaudreuil, Johann; Bendaya, Samy; Faucher, Marc; Coudeyre, Emmanuel; Ribinik, Patricia; Revel, Michel; Rannou, François

2009-12-01

To develop clinical practice guidelines concerning the use of bracing--rest orthosis, knee sleeves and unloading knee braces--for knee osteoarthritis. The French Physical Medicine and Rehabilitation Society (SOFMER) methodology, associating a systematic literature review, collection of everyday clinical practice, and external review by multidisciplinary expert panel, was used. Few high-level studies of bracing for knee osteoarthritis were found. No evidence exists for the effectiveness of rest orthosis. Evidence for knee sleeves suggests that they decrease pain in knee osteoarthritis, and their use is associated with subjective improvement. These actions do not appear to depend on a local thermal effect. The effectiveness of knee sleeves for disability is not demonstrated for knee osteoarthritis. Short- and mid-term follow-up indicates that valgus knee bracing decreases pain and disability in medial knee osteoarthritis, appears to be more effective than knee sleeves, and improves quality of life, knee proprioception, quadriceps strength, and gait symmetry, and decreases compressive loads in the medial femoro-tibial compartment. However, results of response to valgus knee bracing remain inconsistent; discomfort and side effects can result. Thrombophlebitis of the lower limbs has been reported with the braces. Braces, whatever kind, are infrequently prescribed in clinical practice for osteoarthritis of the lower limbs. Modest evidence exists for the effectiveness of bracing--rest orthosis, knee sleeves and unloading knee braces--for knee osteoarthritis, with only low level recommendations for its use. Braces are prescribed infrequently in French clinical practice for osteoarthritis of the knee. Randomized clinical trials concerning bracing in knee osteoarthritis are still necessary.

The effects of a supportive knee brace on leg performance in healthy subjects.

Science.gov (United States)

Veldhuizen, J W; Koene, F M; Oostvogel, H J; von Thiel, T P; Verstappen, F T

1991-12-01

Eight healthy volunteers were fitted with a supportive knee brace (Push Brace 'Heavy') to one knee for a duration of four weeks wherein they were tested before, during and after the application to establish the effect of bracing on performance. The tests consisted of isokinetic strength measurement of knee flexion and extension, 60 meter dash, vertical jump height and a progressive horizontal treadmill test until exhaustion (Vmax) with determination of oxygen uptake, heart rate and plasma lactate concentration. Wearing the brace for one day, the performance indicators showed a decline compared with the test before application (base values). Sprint time was 4% longer (p less than 0.01) and Vmax 6% slower (p less than 0.01). Peak torque of knee flexion at 60 and 240 deg.sec-1 was 6% (p less than 0.05) respectively 9% (p less than 0.05) less. Peak extension torque at 60 deg.sec-1 was 9% less (p less than 0.05). While wearing the brace for four weeks, the test performances were practically identical to their base values. After removal of the brace, all test parameters were statistically similar to the base values. Heart rate at submaximal exercise levels was even lower (p less than 0.05). In conclusion, performance in sports with test-like exercise patterns is not affected by the brace tested. Bracing does not "weaken the knee" as it is widely believed in sports practice.

The effect of ankle brace type on braking response time-A randomised study.

Science.gov (United States)

Dammerer, Dietmar; Waidmann, Cornelia; Haid, Christian; Thaler, Martin; Krismer, Martin; Liebensteiner, Michael C

2015-11-01

The question whether or not a patient with an ankle brace should drive a car is of obvious importance because brake response time (BRT) is considered one of the most important factors for driving safety. Applying a crossover study design, 70 healthy participants (35 women, 35 men) participated in our study. BRT was assessed using a custom-made driving simulator. We assessed BRT under six conditions: without a brace (control) (1), with a typical postoperative ankle brace with adjustable ROM and the settings: unrestricted (2), fixed at 15° (3) plantar flexion, restricted with 15°/50° (4) (dorsal/plantar flexion), a brace for ligament instabilities (5) and an elastic ankle bandage (6). Participants were instructed to apply the brake pedal exclusively with the right foot as quickly as possible on receipt of a visual stimulus. The 70 participants showed significantly impaired BRT with the ankle brace for ROM restriction in the settings: unrestricted (p<0.001), fixed at 15° plantar flexion (p<0.001) and 15°/50° dorsal/plantar flexion (p<0.001) as compared to the control group. BRT was not impaired with the brace for ankle instabilities or the elastic ankle bandage. In conclusion, right-sided ROM restricting ankle braces involve significant impairment of BRT in healthy participants. No such prolonged BRT was found for an elastic ankle bandage or the ligament brace. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of ankle bracing on knee kinetics and kinematics during volleyball-specific tasks.

Science.gov (United States)

West, T; Ng, L; Campbell, A

2014-12-01

The purpose of this study was to examine the effects of ankle bracing on knee kinetics and kinematics during volleyball tasks. Fifteen healthy, elite, female volleyball players performed a series of straight-line and lateral volleyball tasks with no brace and when wearing an ankle brace. A 14-camera Vicon motion analysis system and AMTI force plate were used to capture the kinetic and kinematic data. Knee range of motion, peak knee anterior-posterior and medial-lateral shear forces, and peak ground reaction forces that occurred between initial contact with the force plate and toe off were compared using paired sample t-tests between the braced and non-braced conditions (P volleyball tasks. However, ankle bracing was demonstrated to reduce knee lateral shear forces during all of the lateral movement volleyball tasks. Wearing the Active Ankle T2 brace will not impact knee joint range of motion and may in fact reduce shear loading to the knee joint in volleyball players. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

On the origin of higher braces and higher-order derivations

Czech Academy of Sciences Publication Activity Database

Markl, Martin

2015-01-01

Roč. 10, č. 3 (2015), s. 637-667 ISSN 2193-8407 Institutional support: RVO:67985840 Keywords : Koszul braces * Börjeseon braces * higher-order derivation Subject RIV: BA - General Mathematics Impact factor: 0.600, year: 2015 http://link.springer.com/article/10.1007/s40062-014-0079-2

Early weaning might reduce the psychological strain of Boston bracing

DEFF Research Database (Denmark)

Andersen, Mikkel Ø; Andersen, Gert Rahbek; Thomsen, Karsten

2002-01-01

From 1983 to 1990 a total of 136 patients with adolescent idiopathic scoliosis were treated with the Boston brace. With the aim of examining the social and psychological impact of the brace treatment all patients received a questionnaire at an average of 3.5 years after termination of the treatment...

Versatility of {l_brace}M(30-crown-10){r_brace} (M = K{sup +}, Ba{sup 2+}) as a guest in UO{sub 2}{sup 2+} complexes of 3.1.3.1 - and 3.3.3 homo-oxa-calixarenes

Energy Technology Data Exchange (ETDEWEB)

Masci, B. [Univ Roma La Sapienza, Dipartimento Chim, I-00185 Rome, (Italy); Thuery, P. [CEA Saclay, DSM/DRECAM/SCM, CNRS-URA 331, F-91191 Gif Sur Yvette, (France)

2007-07-01

The reaction between p-R-[3.1.3.1]- or [3.3.3] homo-oxa-calixarenes and uranyl salts in the presence of 30-crown-10 and the alkali or alkaline-earth metal cations K{sup +} or Ba{sup 2+} gives various supramolecular assemblages characterized by 'complex-within-complex' architectures. These can be of the simple nesting or sandwich types, as in [{l_brace}Ba(30-crown-10){r_brace}{l_brace}UO{sub 2}(L{sup 1}){r_brace}]. 2H{sub 2}O.3CHCl{sub 3} (L{sup 1}H{sub 4} p-tert-butyl[3.1.3.1] homo-oxa-calixarene) and [{l_brace}Ba(30-crown-10){r_brace}{l_brace}UO{sub 2}(L{sup 4}){r_brace}{sub 2}].2CHCl{sub 3} (L{sup 4}H{sub 3} p-bromo[3.3.3]homo-oxa-calixarene), respectively, with the cation held in the cavity of the homo-oxa-calixarene complexes in cone conformation by weak interactions, but more original structures arise when uranyl-cation bonds are present. In [{l_brace}Ba(30-crown-10){r_brace}{l_brace}UO{sub 2}(L{sup 2}){r_brace}] (L{sup 2}H{sub 4} p-phenyl[3.1.3.1] homo-oxa-calixarene), the barium ion included in the crown ether is bound to the uranyl oxo group located out of the calixarene cavity, resulting in the formation of a neutral species which self-organizes to form a columnar assembly by auto-inclusion. In [{l_brace}K(30-crown-10){r_brace}{l_brace}UO{sub 2}K(L{sup 1})(H{sub 2}O){sub 3}{r_brace}]{sub 2}.6H{sub 2}O, the nesting-type subunit dimerizes around two oxo-bound potassium ions. Finally, the use of the coordinating solvent dimethylsulfoxide leads to the neutral complex [UO{sub 2}Ba(L{sup 3})(dmso){sub 2}(MeOH)]{sub 2} (L{sup 3}H{sub 4} = p-methyl[3.1.3.1] homo-oxa-calixarene), in which the crown ether is absent and two oxo-, phenoxo- and ether-bound barium atoms ensure the dimerization of the uranyl complex. (authors)

ARTHROMETRIC EVALUATION OF STABILIZING EFFECT OF KNEE FUNCTIONAL BRACING AT DIFFERENT FLEXION ANGLES

Directory of Open Access Journals (Sweden)

Saeedeh Seyed Mohseni

2009-06-01

Full Text Available Previous in-vivo investigations on the stabilizing efficacy of knee bracing for ACL reconstructed patients have been often limited to 20-30 degrees of knee flexion. In this study, the effectiveness of a uniaxial hinged functional brace to improve the knee stability was assessed at 30, 60 and 90 degrees of knee flexion. Arthrometry tests were conducted on 15 healthy subjects before and following wearing the brace and the tibial displacements were measured at up to 150 N anterior forces. Results indicated that functional bracing has a significant stabilizing effect throughout the range of knee flexion examined (p < 0.05. The rate of effectiveness, however, was not consistent across the flexion range, e.g., 50% at 30 degrees and only 4% at 90 degrees. It was suggested that accurate sizing and fitting as well as attention to correct hinge placement relative to the femoral condyles can limit brace migration and improve its effectiveness in mid and deep knee flexion. With using adaptive limb fittings, through flexible pads, and a polycentric joint a more significant improvement of the overall brace performance and efficacy might be obtained

An innovative seismic bracing system based on a superelastic shape memory alloy ring

International Nuclear Information System (INIS)

Gao, Nan; Jeon, Jong-Su; DesRoches, Reginald; Hodgson, Darel E

2016-01-01

Shape memory alloys (SMAs) have great potential in seismic applications because of their remarkable superelasticity. Seismic bracing systems based on SMAs can mitigate the damage caused by earthquakes. The current study investigates a bracing system based on an SMA ring which is capable of both re-centering and energy dissipation. This lateral force resisting system is a cross-braced system consisting of an SMA ring and four tension-only cable assemblies, which can be applied to both new construction and seismic retrofit. The performance of this bracing system is examined through a quasi-static cyclic loading test and finite element (FE) analysis. This paper describes the experimental design in detail, discusses the experimental results, compares the performance with other bracing systems based on SMAs, and presents an Abaqus FE model calibrated on the basis of experimental results to simulate the superelastic behavior of the SMA ring. The experimental results indicate that the seismic performance of this system is promising in terms of damping and re-centering. The FE model can be used in the simulation of building structures using the proposed bracing system. (paper)

SEISMIC FRAGILITY ANALYSIS OF IMPROVED RC FRAMES USING DIFFERENT TYPES OF BRACING

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HAMED HAMIDI JAMNANI

2017-04-01

Full Text Available Application of bracings to increase the lateral stiffness of building structures is a technique of seismic improvement that engineers frequently have recourse to. Accordingly, investigating the role of bracings in concrete structures along with the development of seismic fragility curves are of overriding concern to civil engineers. In this research, an ordinary RC building, designed according to the 1st edition of Iranian seismic code, was selected for examination. According to FEMA 356 code, this building is considered to be vulnerable. To improve the seismic performance of this building, 3 different types of bracings, which are Concentrically Braced Frames, Eccentrically Braced Frames and Buckling Restrained Frames were employed, and each bracing element was distributed in 3 different locations in the building. The researchers developed fragility curves and utilized 30 earthquake records on the Peak Ground Acceleration seismic intensity scale to carry out a time history analysis. Tow damage scale, including Inter-Story Drifts and Plastic Axial Deformation were also used. The numerical results obtained from this investigation confirm that Plastic Axial Deformation is more reliable than conventional approaches in developing fragility curves for retrofitted frames. In lieu of what is proposed, the researchers selected the suitable damage scale and developed and compared log-normal distribution of fragility curves first for the original and then for the retrofitted building.

Introduction to the "Scoliosis" Journal Brace Technology Thematic Series: increasing existing knowledge and promoting future developments

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Grivas Theodoros B

2010-01-01

Full Text Available Abstract Bracing is the main non-surgical intervention in the treatment of idiopathic scoliosis during growth, in hyperkyphosis (and Scheuermann disease and occasionally for spondylolisthesis; it can be used in adult scoliosis, in the elderly when pathological curves lead to a forward leaning posture or in adults after traumatic injuries. Bracing can be defined as the application of external corrective forces to the trunk; rigid supports or elastic bands can be used and braces can be custom-made or prefabricated. The state of research in the field of conservative treatment is insufficient and while it can be stated that there is some evidence to support bracing, we must also acknowledge that today we do not have a common and generally accepted knowledge base, and that instead, individual expertise still prevails, giving rise to different schools of thought on brace construction and principles of correction. The only way to improve the knowledge and understanding of brace type and brace function is to establish a single and comprehensive source of information about bracing. This is what the Scoliosis Journal is going to do through the "Brace Technology" Thematic Series, where technical papers coming from the different schools will be published.

ESR investigation of the reactions of glutathione, cysteine and penicillamine thiyl radicals: competitive formation of RSOcenter dot, Rcenter dot, RSSRcenter dot-. , and RSScenter dot

Energy Technology Data Exchange (ETDEWEB)

Becker, David; Swarts, Steven; Champagne, Mark; Sevilla, M D

1988-05-01

The reactions of cysteine, glutathione and penicillamine thiyl radicals with oxygen and their parent thiols in frozen solutions have been elucidated with e.s.r. The major sulfur radicals observed are: (1) thiyl radicals, RS center dot; (2) disulfide radical anions, RSSR anion radicals; (3) perthiyl radicals, RSS center dot and upon introduction of oxygen; (4) sulfinyl radicals, RSO center dot, where R represents the remainder of the cysteine, glutathione or penicillamine moiety. The radical product observed depends on pH, concentration of thiol, and presence or absence of molecular oxygen. The sulfinyl radical is a ubiquitous intermediate, peroxyl radical attack on thiols may lead to sulfinyl radicals. The authors elaborate the observed reaction sequences that lead to sulfinyl radicals and, using /sup 17/O isotopic substitution studies, demonstrate the oxygen atom in sulfinyl radicals originates from dissolved molecular oxygen. The glutathione radical is found to abstract hydrogen from the ..cap alpha..-carbon position on the cysteine residue of glutathione to form a carbon-centred radical.

Discrepancy in clinical versus radiological parameters describing deformity due to brace treatment for moderate idiopathic scoliosis

Directory of Open Access Journals (Sweden)

Szulc Andrzej

2007-12-01

Full Text Available Abstract Background The shape of the torso in patients with idiopathic scoliosis is considered to reflect the shape of the vertebral column, however the direct correlation between parameters describing clinical deformity and those characterizing radiological curvature was reported to be weak. It is not clear if the management proposed for scoliosis (physiotherapy, brace, surgery affects equally the shape of the axial skeleton and the surface of the body. The aim of the study was to compare clinical deformity of (1 idiopathic scoliosis girls being under brace treatment for radiological curves of 25 to 40 degrees and (2 non treated scoliotic girls matched for age and Cobb angle. Methods Cross-sectional study of 24 girls wearing the brace versus 26 girls without brace treatment, matched for age and Cobb angle. Hypothesis: Patients wearing the brace for more than 6 months, when comparing to patients without brace, may present different external morphology of the trunk, in spite of having similar Cobb angle. Material. Inclusion criteria: girls, idiopathic scoliosis, growing age (10–16 years, Cobb angle minimum 25°, maximum 40°. The braced group consisted of girls wearing a TLSO brace (Cheneau for more than 6 months with minimum of 16 hours per day. The non-braced group consisted of girls first seen for their spinal deformity, previously not treated. The groups presented similar curve pattern. Methods. Scoliometer exam: angle of trunk rotation at three levels of the spine: upper thoracic, main thoracic, lumbar or thoracolumbar. The maximal angle was noted at each level and the sum of three levels was calculated. Posterior trunk symmetry index (POTSI and Hump Sum were measured using surface topography. Results Cobb angle was 34.9° ± 4.8° in braced and 32.7° ± 4.9° in un-braced patients (difference not significant. The age was 14.1 ± 1.6 years in braced patients and 13.1 ± 1.9 years in un-braced group (p = 0.046. The value of angle of trunk

Thermophysical properties of binary mixtures of {l_brace}ionic liquid 2-hydroxy ethylammonium acetate + (water, methanol, or ethanol){r_brace}

Energy Technology Data Exchange (ETDEWEB)

Alvarez, Victor H. [School of Chemical Engineering, State University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas-SP (Brazil); Chemical Engineering Department, ETSE, University of Santiago de Compostela (USC), P.O. Box 15782, Santiago de Compostela (Spain); Mattedi, Silvana [Chemical Engineering Department, Polytechnic School, Federal University of Bahia (UFBA), 40210-630 Salvador-BA (Brazil); Martin-Pastor, Manuel [Unidade de Resonancia Magnetica, RIAIDT, edif. CACTUS, University of Santiago de Compostela (USC), P.O. Box 15706, Santiago de Compostela (Spain); Aznar, Martin [School of Chemical Engineering, State University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas-SP (Brazil); Iglesias, Miguel, E-mail: miguel.iglesias@usc.es [Chemical Engineering Department, ETSE, University of Santiago de Compostela (USC), P.O. Box 15782, Santiago de Compostela (Spain)

2011-07-15

Research highlights: > This paper reports the density and speed of sound data of binary mixtures {l_brace}2-hydroxy ethylammonium acetate + (water, or methanol, or ethanol){r_brace} measured between the temperatures (298.15 and 313.15) K at atmospheric pressure. > The aggregation, dynamic behavior, and hydrogen-bond network were studied using thermo-acoustic, X-ray, and NMR techniques. > The Peng-Robinson equation of state, coupled with the Wong-Sandler mixing rule using the COSMO-SAC model predicted the density of the solutions with relative mean deviations below than 3.0%. - Abstract: In this work, density and speed of sound data of binary mixtures of an ionic liquid consisting of {l_brace}2-hydroxy ethylammonium acetate (2-HEAA) + (water, methanol, or ethanol){r_brace} have been measured throughout the entire concentration range, from the temperature of (288.15 to 323.15) K at atmospheric pressure. The excess molar volumes, variations of the isentropic compressibility, the apparent molar volume, isentropic apparent molar compressibility, and thermal expansion coefficient were calculated from the experimental data. The excess molar volumes were negative throughout the whole composition range. Compressibility data in combination with low angle X-ray scattering and NMR measurements proved that the presence of micelles formed due to ion pair interaction above a critical concentration of the ionic liquid in the mixtures. The Peng-Robinson equation of state coupled with the Wong-Sandler mixing rule and COSMO-SAC model was used to predict densities and the calculated deviations were lower than 3%, for binary mixtures in all composition range.

Control of a flexible bracing manipulator: Integration of current research work to realize the bracing manipulator

Science.gov (United States)

Kwon, Dong-Soo

1991-01-01

All research results about flexible manipulator control were integrated to show a control scenario of a bracing manipulator. First, dynamic analysis of a flexible manipulator was done for modeling. Second, from the dynamic model, the inverse dynamic equation was derived, and the time domain inverse dynamic method was proposed for the calculation of the feedforward torque and the desired flexible coordinate trajectories. Third, a tracking controller was designed by combining the inverse dynamic feedforward control with the joint feedback control. The control scheme was applied to the tip position control of a single link flexible manipulator for zero and non-zero initial condition cases. Finally, the contact control scheme was added to the position tracking control. A control scenario of a bracing manipulator is provided and evaluated through simulation and experiment on a single link flexible manipulator.

Twitter analysis of the orthodontic patient experience with braces vs Invisalign.

Science.gov (United States)

Noll, Daniel; Mahon, Brendan; Shroff, Bhavna; Carrico, Caroline; Lindauer, Steven J

2017-05-01

To examine the orthodontic patient experience having braces compared with Invisalign by means of a large-scale Twitter sentiment analysis. A custom data collection program was created that collected tweets containing the words "braces" or "Invisalign" for a period of 5 months. A hierarchal Naïve Bayes sentiment analysis classifier was developed to sort the tweets into five categories: positive, negative, neutral, advertisement, or not applicable. Each category was then analyzed for specific content. A total of 419,363 tweets applicable to orthodontics were collected. Users posted significantly more positive tweets (61%) than they did negative tweets (39%; P ≤ .0001). There was no significant difference in the distribution of positive and negative sentiment between braces and Invisalign tweets (P = .4189). Positive orthodontics-related tweets often highlighted gratitude for a great smile accompanied with selfies. Negative orthodontic tweets frequently focused on pain. Twitter users expressed more positive than negative sentiment about orthodontic treatment with no significant difference in sentiment between braces and Invisalign tweets.

An Experimental Study on Non-Compression X-Bracing Systems Using Carbon Fiber Composite Cable for Seismic Strengthening of RC Buildings

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Kang Seok Lee

2015-09-01

Full Text Available Cross-bracing (X-bracing is one of the most popular methods of seismic retrofitting, and has been shown to significantly increase the structural stiffness and strength of buildings. Conventional steel X-bracing methods typically exhibit brittle failure at the connection between the brace and the building, or buckling failure of the braces. This study investigated the structural properties of a new type of non-compression X-bracing system using carbon fiber composite cable (CFCC. This non-compression X-bracing system uses CFCC bracing and bolt connections between structural members and the terminal fixer of the CFCC, instead of conventional steel bracing. The aim is to overcome the brittle and buckling failures that can occur at the connection and bracings with conventional steel X-bracing methods. We carried out cyclic loading tests, and the maximum load carrying capacity and deformation were investigated, as well as hysteresis in the lateral load–drift relations. The test results revealed that the CFCC X-bracing system installed in reinforced concrete frames enhanced the strength markedly, and buckling failure of the bracing was not observed.

Effectiveness of an Outside-the-Boot Brace in Reducing Parachuting Related Ankle Injuries

National Research Council Canada - National Science Library

Schmidt, M. D; Sulsky, S. I; Amoroso, P. J

2005-01-01

.... Multiple logistic regression analysis estimated adjusted odds ratios (OR) and 95% confidence intervals for injury outcomes, comparing pre and post brace periods to the brace protocol period. Setting...

Gait comparison of subjects with hemiplegia walking unbraced, with ankle-foot orthosis, and with Air-Stirrup brace.

Science.gov (United States)

Burdett, R G; Borello-France, D; Blatchly, C; Potter, C

1988-08-01

The effects of the Air-Stirrup (AS) standard ankle brace on the gait of 19 subjects with hemiplegia resulting from a cerebrovascular accident who exhibited excessive subtalar joint motion were studied. Videotaped trials and footprint analyses were used to measure subjects' hip, knee, and ankle sagittal plane angles; inversion and eversion of the calcaneus; and time-distance gait characteristics. A one-way analysis of variance for repeated measures was used to compare the gait of 19 subjects with the AS brace and unbraced and 11 subjects with the AS brace, unbraced, and with an ankle-foot orthosis. The AS brace was associated with more calcaneal stability during standing than the unbraced condition. The ankle-foot orthosis was associated with less plantar flexion at foot-strike than either the AS brace or unbraced condition. Both the AS brace and the ankle-foot orthosis were associated with less mid-swing plantar flexion and increased step length on the paretic side compared with no brace. These results support the effectiveness of the AS brace in controlling inversion and eversion instability in patients with hemiplegia.

Chinese Adaptation of the Bad Sobernheim Stress Questionnaire for Patients With Adolescent Idiopathic Scoliosis Under Brace Treatment.

Science.gov (United States)

Xu, Ximing; Wang, Fei; Yang, Mingyuan; Huang, Qikai; Chang, Yifan; Wei, Xianzhao; Bai, Yushu; Li, Ming

2015-08-01

Bad Sobernheim Stress Questionnaire (BSSQ)-Deformity and BSSQ-Brace are the most widely used instruments for evaluating stress levels in adolescent idiopathic scoliosis (AIS) patients under brace treatment, and good reliability and validity have been demonstrated across different cultures. Great stress has been found among many adolescents, becoming a major concern for professionals. However, no previous research has addressed the cultural adaptations and psychometric testing of BSSQ-Deformity and BSSQ-Brace in China or the stress levels in AIS patients. The purposes of our study were to evaluate the cross-cultural adaptation and validation of the BSSQ-Deformity and BSSQ-Brace and to investigate stress levels in Chinese (AIS) patients under brace treatment.The original (German) versions of BSSQ-Deformity and BSSQ-Brace were cross-culturally translated according to international guidelines. Psychometric properties such as reliability and construct validity were tested. Eighty-six AIS patients were included in our study, and 50 patients paid a second visit 3 to 7 days later to test reproducibility. Cronbach α and the intraclass coefficient were determined to assess internal consistency and reproducibility. Scoliosis Research Society patient questionnaire-22 (SRS-22) was applied to evaluate construct validity.The mean BSSQ-Deformity and BSSQ-Brace scores were 15.3 and 13.4 points, respectively. Severe stress was observed in 12% of patients due to brace treatment. Item analysis demonstrated that each item was scored under a normal distribution with no redundancy. Psychometric analysis revealed excellent internal consistency (Cronbach α = 0.85 and 0.80, respectively) and reproducibility (intraclass correlation coefficient = 0.85 and 0.90, respectively) for BSSQ-Deformity and BSSQ-Brace. The correlation coefficients of BSSQ-Deformity, BSSQ-Brace and SRS-22 were 0.48 and 0.63, respectively.In conclusion, BSSQ-Deformity and BSSQ-Brace have been successfully

Low-Cost Alternative External Rotation Shoulder Brace and Review of Treatment in Acute Shoulder Dislocations

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Lacy, Kyle

2015-01-01

Full Text Available Traumatic dislocations of the shoulder commonly present to emergency departments (EDs. Immediate closed reduction of both anterior and posterior glenohumeral dislocations is recommended and is frequently performed in the ED. Recurrence of dislocation is common, as anteroinferior labral tears (Bankart lesions are present in many anterior shoulder dislocations.14,15,18,23 Immobilization of the shoulder following closed reduction is therefore recommended; previous studies support the use of immobilization with the shoulder in a position of external rotation, for both anterior and posterior shoulder dislocations.7-11,19 In this study, we present a technique for assembling a low-cost external rotation shoulder brace using materials found in most hospitals: cotton roll, stockinette, and shoulder immobilizers. This brace is particularly suited for the uninsured patient, who lacks the financial resources to pay for a pre-fabricated brace out of pocket. We also performed a cost analysis for our low-cost external rotation shoulder brace, and a cost comparison with pre-fabricated brand name braces. At our institution, the total materials cost for our brace was $19.15. The cost of a pre-fabricated shoulder brace at our institution is $150 with markup, which is reimbursed on average at $50.40 according to our hospital billing data. The low-cost external rotation shoulder brace is therefore a more affordable option for the uninsured patient presenting with acute shoulder dislocation. [West J Emerg Med. 2015;16(1:114–120.

"Brace Technology" Thematic Series - The Lyon approach to the conservative treatment of scoliosis

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Lecante Cyril

2011-03-01

Full Text Available Abstract The Lyon Brace, or adjustable multi-shell brace, has been used for more than 60 years. The use and function of the Lyon Brace includes: - The utilization of one or two corrective plaster casts, which enables a true lengthening of the concave ligaments. - An oriented CAD-CAM moulding in 3D auto correction after the removal of the plaster cast. - A blueprint adapted to Lenke's classification. - A specific physiotherapy program. Background Pierre Stagnara created the Lyon Brace in 1947. The brace has the following characteristics: - It adjusts to allow for a child's growth of up to seven centimetres and for an increase in weight of up to seven kilograms. - It is 'active' in that the rigidity of the PMM (polymetacrylate of methyl structure stimulates the user to auto-correct. The active axial auto-correction decreases the pressures of the brace on the trunk. - It is decompressive in that the effect of extension between the two pelvic and scapular girdles decreases the pressure on the intervertebral disc allowing for more effective pushes in the other planes. - It is symmetrical making it both more aesthetically pleasing and easier to build. - It is stable at both shoulders and pelvic girdle, facilitating the intermediate 3D corrections. - It is transparent. The pressure of the shells on the skin can be directly controlled so "pads" are usually not necessary. Brace description Two metal bars are fixed vertically, one anterior the other posterior and all shells are attached from the bottom to the top in this order: - Two pelvic shells ensure an optimal stability of the brace. - One lumbar shell T12-L4, which can be either independent or extending, at the abdominal chondrocostal level. - One thoracic shell at the level of the thoracic convexity. - One opposite thoracic shell used as a counter push. - One shoulder balance shell on the side of the thoracic convexity. Long term follow up results This is a retrospective study of 1,338 completed

A Survey of Parachute Ankle Brace Breakages

National Research Council Canada - National Science Library

Knapik, Joseph J; Spiess, Anita; Darakjy, Salima; Grier, Tyson; Manning, Fred; Livingston, Elaine; Swedler, David; Amoroso, Paul; Jones, Bruce H

2008-01-01

...) of the Defense Safety Oversight Council (DSOC) to evaluate the parachute ankle brace (PAB). Information provided by the questionnaire identified potential injury risk factors and comments on the PAB...

Upgrading the seismic capacity of existing RC buildings using buckling restrained braces

Directory of Open Access Journals (Sweden)

Hamdy Abou-Elfath

2017-06-01

Full Text Available Many existing RC buildings do not meet the lateral strength requirements of current seismic codes and are vulnerable to significant damage or collapse in the event of future earthquakes. In the past few decades, buckling-restrained braces have become increasingly popular as a lateral force resisting system because of their capability of improving the strength, the stiffness and the energy absorbing capacity of structures. This study evaluates the seismic upgrading of a 6-story RC-building using single diagonal buckling restrained braces. Seismic evaluation in this study has been carried out by static pushover analysis and time history earthquake analysis. Ten ground motions with different PGA levels are used in the analysis. The mean plus one standard deviation values of the roof-drift ratio, the maximum story drift ratio, the brace ductility factors and the member strain responses are used as the basis for the seismic performance evaluations. The results obtained in this study indicate that strengthening of RC buildings with buckling restrained braces is an efficient technique as it significantly increases the PGA capacity of the RC buildings. The results also indicate the increase in the PGA capacity of the RC building with the increase in the amount of the braces.

Efficacy, safety, and economics of bracing after spine surgery: a systematic review of the literature.

Science.gov (United States)

Zhu, Mary P; Tetreault, Lindsay A; Sorefan-Mangou, Fatimah; Garwood, Philip; Wilson, Jefferson R

2018-01-31

Bracing is often used after spinal surgery to immobilize the spine, improve fusion, and relieve pain. However, controversy exists regarding the efficacy, necessity, and safety of various bracing techniques in the postsurgical setting. In this systematic review, we aimed to compare the effectiveness, safety, and cost-effectiveness of postoperative bracing versus no postoperative bracing after spinal surgery in patients with several common operative spinal pathologies. A systematic review was carried out to compare postoperative bracing and no postoperative bracing. A systematic search was conducted of MEDLINE, Embase, and the Cochrane Collaboration Library from 1970 to May 2017, supplemented by manual searching of the reference list of relevant studies and previously published reviews. Studies were included if they compared disability, quality of life, functional impairment, radiographic outcomes, cost-effectiveness, or complications between patients treated with postoperative bracing and patients not receiving any postoperative bracing. Each article was critically appraised independently by two reviewers, and the overall body of evidence was rated using guidelines outlined by the Grading of Recommendation Assessment, Development and Evaluation (GRADE) Working Group. Of the 858 retrieved citations, 5 studies met the inclusion criteria and were included in this review, consisting of 4 randomized controlled trials and 1 prospective cohort study. Low to moderate evidence suggests that there are no significant differences in most measures of disability, pain, quality of life, functional impairment, radiographic outcomes, and safety between groups. Isolated studies reported statistically significant and inconsistent differences between groups with respect to Neck Disability Index at 6 weeks postoperatively or Short Form-36 Physical Component Score at 1.5, 3, 6, and 12 months postoperatively. Based on limited evidence, postoperative bracing does not result in improved

An equivalent frequency approach for determining non-linear effects on pre-tensioned-cable cross-braced structures

Science.gov (United States)

Giaccu, Gian Felice

2018-05-01

Pre-tensioned cable braces are widely used as bracing systems in various structural typologies. This technology is fundamentally utilized for stiffening purposes in the case of steel and timber structures. The pre-stressing force imparted to the braces provides to the system a remarkable increment of stiffness. On the other hand, the pre-tensioning force in the braces must be properly calibrated in order to satisfactorily meet both serviceability and ultimate limit states. Dynamic properties of these systems are however affected by non-linear behavior due to potential slackening of the pre-tensioned brace. In the recent years the author has been working on a similar problem regarding the non-linear response of cables in cable-stayed bridges and braced structures. In the present paper a displacement-based approach is used to examine the non-linear behavior of a building system. The methodology operates through linearization and allows obtaining an equivalent linearized frequency to approximately characterize, mode by mode, the dynamic behavior of the system. The equivalent frequency depends on both the mechanical characteristics of the system, the pre-tensioning level assigned to the braces and a characteristic vibration amplitude. The proposed approach can be used as a simplified technique, capable of linearizing the response of structural systems, characterized by non-linearity induced by the slackening of pre-tensioned braces.

Effect of hip braces on brake response time: Repeated measures designed study.

Science.gov (United States)

Dammerer, Dietmar; Waidmann, Cornelia; Huber, Dennis G; Krismer, Martin; Haid, Christian; Liebensteiner, Michael C

2017-08-01

The question whether or not a patient with a hip brace should drive a car is of obvious importance because the advice given to patients to resume driving is often anecdotal as few scientific data are available on this specific subject. To assess driving ability (brake response time) with commonly used hip braces. Repeated measures design. Brake response time was assessed under six conditions: (1) without a brace (control), (2) with a typical postoperative hip brace with adjustable range of motion and the settings: unrestricted, (3) flexion limited to 70°, (4) extension blocked at 20° hip flexion, (5) both flexion and extension limited (20°/70°) and (6) an elastic hip bandage. Brake response time was assessed using a custom-made driving simulator as used in previous studies. The participants were a convenience sample of able-bodied participants. A total of 70 participants (35 women and 35 men) participated in our study. Mean age was 31.1 (standard deviation: 10.6; range: 21.7-66.4) years. A significant within-subject effect for brake response time was found ( p = 0.009), but subsequent post hoc analyses revealed no significant differences between control and the other settings. Based on our findings, it does not seem mandatory to recommend driving abstinence for patients wearing a hip orthosis. We suggest that our results be interpreted with caution, because (1) an underlying pathological hip condition needs to be considered, (2) the ability to drive a car safely is multifactorial and brake response time is only one component thereof and (3) brake response time measurements were performed only with healthy participants. Clinical relevance Hip braces are used in the context of joint-preserving and prosthetic surgery of the hip. Therefore, clinicians are confronted with the question whether to allow driving a car with the respective hip brace or not. Our data suggest that hip braces do not impair brake response time.

Light Steel-Timber Frame with Composite and Plaster Bracing Panels

OpenAIRE

Scotta, Roberto; Trutalli, Davide; Fiorin, Laura; Pozza, Luca; Marchi, Luca; Stefani, Lorenzo  De

2015-01-01

The proposed light-frame structure comprises steel columns for vertical loads and an innovative bracing system to efficiently resist seismic actions. This seismic force resisting system consists of a light timber frame braced with an Oriented Strand Board (OSB) sheet and an external technoprene plaster-infilled slab. Steel brackets are used as foundation and floor connections. Experimental cyclic-loading tests were conduced to study the seismic response of two shear-wall specimens. A numerica...

Surface tension, density, and speed of sound for the ternary mixture {l_brace}diethyl carbonate + p-xylene + decane{r_brace}

Energy Technology Data Exchange (ETDEWEB)

Mosteiro, Laura; Casas, Lidia M. [Departamento de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Vigo, Lagoas Marcosende s/n, 36310 Vigo (Spain); Legido, Jose L. [Departamento de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Vigo, Lagoas Marcosende s/n, 36310 Vigo (Spain)], E-mail: xllegido@uvigo.es

2009-05-15

This paper reports the results of a new experimental study of thermophysical properties for the ternary mixture of {l_brace}diethyl carbonate + p-xylene + decane{r_brace}. Surface tension has been measured at 298.15 K and, density and speed of sound have been measured in the temperature range T = (288.15 to 308.15) K. Excess molar volumes, excess isentropic compressibilities, and surface tension deviations, have been calculated from experimental data. Surface tension deviations have been correlated with Cibulka equation and Nagata and Tamura equation was used for the other excess properties. Good accuracy has been obtained. These excess magnitudes are discussed qualitatively in terms of the nature and type of intermolecular interactions of the components involved.

Evaluating the ductility characteristics of self-centering buckling-restrained shape memory alloy braces

Science.gov (United States)

Abou-Elfath, Hamdy

2017-05-01

Recently, self-centering earthquake resistant systems have attracted attention because of their promising potential in controlling the residual drifts and reducing repair costs after earthquake events. Considerable portion of self-centering research is based on using short-segment superelastic shape memory alloy (SMA) braces as strengthening technique because of the lower modulus of elasticity of SMA in comparison with that of steel. The goal of this study is to investigate the ductility characteristics of these newly proposed short-segment SMA braces to evaluate their safety levels against fracture failures under earthquake loading. This goal has been achieved by selecting an appropriate seismic performance criterion for steel frames equipped with SMA braces, defining the level of strain capacity of SMA and calculating the strain demands in the SMA braces by conducting a series of pushover and earthquake time history analyzes on typical frame structure. The results obtained in this study indicated the inability of short-segment SMA designs to provide adequate ductility to the lateral resistant systems. An alternative approach is introduced by using hybrid steel-SMA braces that are capable of controlling the residual drifts and providing the structure with adequate lateral stiffness.

Prophylactic knee bracing alters lower-limb muscle forces during a double-leg drop landing.

Science.gov (United States)

Ewing, Katie A; Fernandez, Justin W; Begg, Rezaul K; Galea, Mary P; Lee, Peter V S

2016-10-03

Anterior cruciate ligament (ACL) injury can be a painful, debilitating and costly consequence of participating in sporting activities. Prophylactic knee bracing aims to reduce the number and severity of ACL injury, which commonly occurs during landing maneuvers and is more prevalent in female athletes, but a consensus on the effectiveness of prophylactic knee braces has not been established. The lower-limb muscles are believed to play an important role in stabilizing the knee joint. The purpose of this study was to investigate the changes in lower-limb muscle function with prophylactic knee bracing in male and female athletes during landing. Fifteen recreational athletes performed double-leg drop landing tasks from 0.30m and 0.60m with and without a prophylactic knee brace. Motion analysis data were used to create subject-specific musculoskeletal models in OpenSim. Static optimization was performed to calculate the lower-limb muscle forces. A linear mixed model determined that the hamstrings and vasti muscles produced significantly greater flexion and extension torques, respectively, and greater peak muscle forces with bracing. No differences in the timings of peak muscle forces were observed. These findings suggest that prophylactic knee bracing may help to provide stability to the knee joint by increasing the active stiffness of the hamstrings and vasti muscles later in the landing phase rather than by altering the timing of muscle forces. Further studies are necessary to quantify whether prophylactic knee bracing can reduce the load placed on the ACL during intense dynamic movements. Copyright © 2016 Elsevier Ltd. All rights reserved.

Inelastic behavior of cold-formed braced walls under monotonic and cyclic loading

Science.gov (United States)

Gerami, Mohsen; Lotfi, Mohsen; Nejat, Roya

2015-06-01

The ever-increasing need for housing generated the search for new and innovative building methods to increase speed and efficiency and enhance quality. One method is the use of light thin steel profiles as load-bearing elements having different solutions for interior and exterior cladding. Due to the increase in CFS construction in low-rise residential structures in the modern construction industry, there is an increased demand for performance inelastic analysis of CFS walls. In this study, the nonlinear behavior of cold-formed steel frames with various bracing arrangements including cross, chevron and k-shape straps was evaluated under cyclic and monotonic loading and using nonlinear finite element analysis methods. In total, 68 frames with different bracing arrangements and different ratios of dimensions were studied. Also, seismic parameters including resistance reduction factor, ductility and force reduction factor due to ductility were evaluated for all samples. On the other hand, the seismic response modification factor was calculated for these systems. It was concluded that the highest response modification factor would be obtained for walls with bilateral cross bracing systems with a value of 3.14. In all samples, on increasing the distance of straps from each other, shear strength increased and shear strength of the wall with bilateral bracing system was 60 % greater than that with lateral bracing system.

Seismic Response of Steel Braced Building Frame Considering Soil Structure Interaction (SSI): An Experimental Study

Science.gov (United States)

Hirave, Vivek; Kalyanshetti, Mahesh

2018-02-01

Conventional fixed-base analysis ignoring the effect of soil-flexibility may result in unsafe design. Therefore, to evaluate the realistic behavior of structure the soil structure interaction (SSI) effect shall be incorporated in the analysis. In seismic analysis, provision of bracing system is one of the important option for the structure to have sufficient strength with adequate stiffness to resist lateral forces. The different configuration of these bracing systems alters the response of buildings, and therefore, it is important to evaluate the most effective bracing systems in view point of stability against SSI effect. In present study, three RC building frames, G+3, G+5 and G+7 and their respective scaled down steel model with two types of steel bracing system incorporating the effect of soil flexibility is considered for experimental and analytical study. The analytical study is carried out using Elastic continuum approach and the experimental study is carried out using Shake Table. The influence of SSI on various seismic parameters is presented. The study reveals that, steel bracing system is beneficial to control SSI effect and it is observed that V bracing is more effective, in resisting seismic load considering SSI.

An experimental investigation on the ultimate strength of epoxy repaired braced partial infilled RC frames

Science.gov (United States)

Dubey, Shailendra Kumar Damodar; Kute, Sunil

2014-09-01

Due to earthquake, buildings are damaged partially or completely. Particularly structures with soft storey are mostly affected. In general, such damaged structures are repaired and reused. In this regard, an experimental investigation was planned and conducted on models of single-bay, single-storey of partial concrete infilled reinforced concrete (RC) frames up to collapse with corner, central and diagonal steel bracings. Such collapsed frames were repaired with epoxy resin and retested. The initiative was to identify the behaviour, extent of restored ultimate strength and deflection of epoxy-retrofitted frames in comparison to the braced RC frames. The performance of such frames has been considered only for lateral loads. In comparison to bare RC frames, epoxy repaired partial infilled frames have significant increase in the lateral load capacity. Central bracing is more effective than corner and diagonal bracing. For the same load, epoxy repaired frames have comparable deflection than similar braced frames.

A displacement-based approach for determining non-linear effects on pre-tensioned-cable cross-braced structures

Science.gov (United States)

Giaccu, Gian Felice; Caracoglia, Luca

2017-04-01

Pre-tensioned-cable bracing systems are widely employed in structural engineering to limit lateral deflections and stabilize structures. A suitable configuration of the pre-tensioned-cable bracing systems in a structure is an important issue since the internal force distribution, emerging from the interaction with the existing structure, significantly affects the structural dynamic behavior. The design, however, is often based on the intuition and the previous experience of the engineer. In recent years, the authors have been investigating the non-linear dynamic response of cable systems, installed on cable-stayed bridges, and in particular the so-called "cable-cross-tie systems" forming a cable network. The bracing cables (cross-ties) can exhibit slackening or snapping. Therefore, a non-linear unilateral model, combined with the taut-cable theory, is required to simulate the incipient slackening conditions in the stays. Capitalizing from this work on non-linear cable dynamics, this paper proposes a new approach to analyze, in laterally- braced truss structures, the unilateral effects and dynamic response accounting for the loss in the pre-tensioning force imparted to the bracing cables. This effect leads to non-linear vibration of the structure. In this preliminary study, the free vibrations of the structure are investigated by using the "Equivalent Linearization Method". A performance coefficient, a real positive number between 0.5 and 1.0, is defined and employed to monitor the relative reduction in the apparent stiffness of the braces during structural vibration, "mode by mode". It is shown that the system can exhibit alternate unilateral behavior of the cross-braces. A reduction of the performance coefficient close to fifty percent is observed in the braces when the initial pre-tensioning force is small. On the other hand the performance coefficient tends to one in the case of a high level of pre-stress. It is concluded that the performance coefficient may

Determination of brace forces caused by construction loads and wind loads during bridge construction.

Science.gov (United States)

2014-04-01

The first objective of this study was to develop procedures for determining bracing forces during bridge construction. : Numerical finite element models and analysis techniques were developed for evaluating brace forces induced by construction loads ...

Ferroelectric TGS ((NH sub 2 CH sub 2 COOH) sub 3 centre dot H sub 2 SO sub 4) under high pressure

CERN Document Server

Kobayashi, Y; Furuta, H; Endo, S; Deguchi, K

2002-01-01

The ferroelectric transition temperature T sub c of (NH sub 2 CH sub 2 COOH) sub 3 centre dot H sub 2 SO sub 4 (TGS), which is a typical order-disorder-type ferroelectric, was determined by dielectric constant and Raman scattering measurements under high pressure. T sub c increased, passed through a maximum and then decreased slightly with increasing pressure, and then abruptly dropped at about 2.5 GPa, where a transition to a new high-pressure phase was confirmed to exist. A tentative p-T phase diagram was proposed for TGS.

Light Steel-Timber Frame with Composite and Plaster Bracing Panels

Directory of Open Access Journals (Sweden)

Roberto Scotta

2015-11-01

Full Text Available The proposed light-frame structure comprises steel columns for vertical loads and an innovative bracing system to efficiently resist seismic actions. This seismic force resisting system consists of a light timber frame braced with an Oriented Strand Board (OSB sheet and an external technoprene plaster-infilled slab. Steel brackets are used as foundation and floor connections. Experimental cyclic-loading tests were conduced to study the seismic response of two shear-wall specimens. A numerical model was calibrated on experimental results and the dynamic non-linear behavior of a case-study building was assessed. Numerical results were then used to estimate the proper behavior factor value, according to European seismic codes. Obtained results demonstrate that this innovative system is suitable for the use in seismic-prone areas thanks to the high ductility and dissipative capacity achieved by the bracing system. This favorable behavior is mainly due to the fasteners and materials used and to the correct application of the capacity design approach.

Light Steel-Timber Frame with Composite and Plaster Bracing Panels.

Science.gov (United States)

Scotta, Roberto; Trutalli, Davide; Fiorin, Laura; Pozza, Luca; Marchi, Luca; De Stefani, Lorenzo

2015-11-03

The proposed light-frame structure comprises steel columns for vertical loads and an innovative bracing system to efficiently resist seismic actions. This seismic force resisting system consists of a light timber frame braced with an Oriented Strand Board (OSB) sheet and an external technoprene plaster-infilled slab. Steel brackets are used as foundation and floor connections. Experimental cyclic-loading tests were conduced to study the seismic response of two shear-wall specimens. A numerical model was calibrated on experimental results and the dynamic non-linear behavior of a case-study building was assessed. Numerical results were then used to estimate the proper behavior factor value, according to European seismic codes. Obtained results demonstrate that this innovative system is suitable for the use in seismic-prone areas thanks to the high ductility and dissipative capacity achieved by the bracing system. This favorable behavior is mainly due to the fasteners and materials used and to the correct application of the capacity design approach.

An Experimental Investigation on the Ultimate Strength of Partially Infilled: Braced Steel Frames

Science.gov (United States)

Dubey, Shailendra Kumar Damodar; Kute, Sunil Y.

2017-12-01

Infilled walls are usually, considered as non-structural elements. However, these walls are effective in carrying lateral loads. In this regard, an experimental investigation was planned and conducted to study the effect of braced and partially infilled steel frames with cement mortar and concrete in comparison to the bare frames. All these frames were tested up to collapse and subjected only to horizontal loads to obtain an effective and possible solution for soft storey which are generally not infilled. In comparison to bare steel frames, partially infilled frames have an increase of lateral load capacity by 45-60%. Central bracing is more effective than that of the corner bracing. For the same load partially infilled frames have significantly less deflection than that of the bare frames. A reduced load factor is suggested for the design of soft storey columns with the partial infills. A mathematical model has been proposed to calculate the theoretical ultimate load for the braced, cement mortar and concrete partial infilled frames.

Influence of functional knee bracing on the isokinetic and functional tests of anterior cruciate ligament deficient patients.

Directory of Open Access Journals (Sweden)

Niyousha Mortaza

Full Text Available Use of functional knee braces has been suggested to provide protection and to improve kinetic performance of the knee in Anterior cruciate ligament(ACL-injured patients. However, many athletes might refrain from wearing the braces because of the fear of performance hindrance in the playing field. The aim of this study was to examine the effect of three functional knee brace/sleeves upon the isokinetic and functional performance of ACL-deficient and healthy subjects. Six anterior cruciate ligament deficient (29.0 ± 5.3 yrs., 175.2 ± 5.4 cm, and 73.0 ± 10.0 kg and six healthy male subjects (27.2 ± 3.7 yrs., 176.4 ± 6.4 cm, and 70.3 ± 6.9 kg were selected. The effect of a custom-made functional knee brace, and two neoprene knee sleeves, one with four metal supports and one without support were examined via the use of isokinetic and functional tests in four sets (non-braced,wearing functional knee brace,and wearing the sleeves. Cross-over hop and single leg vertical jump test were performed and jump height, and hop distance were recorded. Peak torque to body weight ratio and average power in two isokinetic velocities(60°.s(-1,180°.s(-1 were recorded and the brace/sleeves effect was calculated as the changes in peak torque measured in the brace/sleeves conditions, expressed as a percentage of peak torque measured in non-braced condition. Frequency content of the isokinetic torque-time curves was also analyzed. Wilcoxon signed rank test was used to compare the measured values in four test conditions within each control and ACL-deficient group,and Mann-Whitney U test was used for the comparison between the two groups. No significant differences in peak torque, average power, torque-time curve frequency content, vertical-jump and hop measurements were found within the experimental and the non-braced conditions (p>0.05. Although the examined functional knee brace/sleeves had no significant effect on the knee muscle performance, there have been

Stark-shift of impurity fundamental state in a lens shaped quantum dot

Science.gov (United States)

Aderras, L.; Bah, A.; Feddi, E.; Dujardin, F.; Duque, C. A.

2017-05-01

We calculate the Stark effect and the polarisability of shallow-donor impurity located in the centre of lens shaped quantum dot by a variational method and in the effective-mass approximation. Our theoretical model assumes an infinite confinement to describe the barriers at the dot boundaries and the electric field is considered to be applied in the z-direction. The systematic theoretical investigation contains results with the quantum dot size and the strength of the external field. Our calculations reveal that the interval wherein the polarisability varies depends strongly on the dot size.

Treatment of the idiopathic scoliosis with brace and physiotherapy.

Science.gov (United States)

Hundozi-Hysenaj, Hajrije; Dallku, Iliriana Boshnjaku; Murtezani, Ardiana; Rrecaj, Shkurte

2009-01-01

Scoliosis is a three-dimensional deformation of the spine with a lateral curvature or deviation greater than 10 degrees and associated with vertebral rotation. Many conservative treatments are available for adolescents with idiopathic scoliosis, but the evidence for their effectiveness is still questioned. The objective of this study was to define the effectiveness of braces and individual physiotherapy for the comprehensive treatment of idiopathic scoliosis in adolescents. A retrospective study of 57 children with idiopathic thoracic dextroscoliosis with the magnitude of the thoracic curve between 20 degrees-35 degrees, treated in Orthopedic and Physiatrist Clinic as well as National Ortho-prosthetic Center within University Clinical Center of Kosova in Prishtina, during the period of 2003-2006. Inclusion of kinesitherapy in the comprehensive management of idiopathic scoliosis varied in the improvement of the muscle strength (satisfied and moderate) in almost 80% of the children while the correction of the curve was small in approximately 42.1% of cases. For children with idiopathic scoliosis, who require braces, an exercise program helps chest mobility, muscle strength, proper breathing flexibility in the spine, correct posture and keeps muscles in tone so that the transition period after brace removal is easier.

[Influence of Ankle Braces on the Prevalence of Ankle Inversion Injuries in the Swiss Volleyball National League A].

Science.gov (United States)

Jaggi, J; Kneubühler, S; Rogan, S

2016-06-01

Ankle inversion is a common injury among volleyball players. The injury rate during a game is 2.1 times higher than during training. As a result, the preventive use of ankle braces is frequently observed in Swiss volleyball leagues. Studies have shown that ankle braces have a preventive effect on the prevalence of ankle inversion. In Switzerland there has been no investigation into the preventive use of braces and their influence on prevalence. For this reason, the goals of this study are 1) to determine when, why and by whom ankle braces are worn and 2) to evaluate the injury rate of users and non-users of ankle braces. A modified questionnaire was sent to 18 men's and women's teams of the Swiss National League A. The questionnaire included questions about injury rates and the circumstances of ankle inversion injuries. The data were statistically analysed with Microsoft Excel 2012 and SPSS Version 20. The overall response rate was 61 %, allowing data from 181 players to be analysed. 33 % (59 of 181) of the players used an ankle brace. There was a statistically significant difference in the prevalence of ankle inversion between users (12 injured) and non-users (8 injured) (p = 0.006). Wearing an ankle brace during training or during a game made no difference in the prevention of injuries (p = 0.356). More athletes were injured during training (n = 13) than during a game (n = 7). The results of the present study indicate that volleyball players preferably wear ankle braces to prevent injury. More than one third of the players in the study wore an ankle brace, 60 % for primary prevention and 40 % for secondary prevention due to a previous injury. The study shows that significantly more users than non-users of ankle braces were injured. This is contrary to literature. Furthermore it was shown that more injuries occur during training than during a game. This finding results from the fact that ankle braces were rarely worn during training. It is

Bracing can partially limit tibial rotation during stressful activities after anterior crucial ligament reconstruction with a hamstring graft.

Science.gov (United States)

Giotis, D; Paschos, N K; Zampeli, F; Pappas, E; Mitsionis, G; Georgoulis, A D

2016-09-01

Hamstring graft has substantial differences with BPTB graft regarding initial mechanical strength, healing sequence, and vascularization, which may imply that a different approach during rehabilitation period is required. The purpose of this study was to investigate the influence of knee bracing on tibial rotation in ACL-reconstructed patients with a hamstring autograft during high loading activities. The hypothesis was that there would be a decrease in tibial rotation in the ACL-reconstructed braced knee as compared to the unbraced knee. Twenty male patients having undergone unilateral ACL reconstruction with a semitendinosus/gracilis autograft were assessed. Kinematic data were collected with an eight-camera optoelectronic system during two stressful tasks: (1) descending from a stair and subsequent pivoting; and (2) landing from a platform and subsequent pivoting. In each patient, three different experimental conditions were evaluated: (A) wearing a prophylactic brace (braced condition); (B) wearing a patellofemoral brace (sleeved condition); (C) without brace (unbraced condition). The intact knee without brace served as a control. Tibial rotation was significantly lower in the intact knee compared to all three conditions of the ACL-reconstructed knee (P≤0.01 for both tasks). Presence of a brace or sleeve resulted in lower tibial rotation than in the unbraced condition (p=0.003 for descending/pivot and P=0.0004 for landing/pivot). The braced condition resulted in lower rotation than the sleeved condition for descending/pivoting (P=0.031) while no differences were found for landing/pivoting (P=0.230). Knee bracing limited the excessive tibial rotation during pivoting under high loading activities in ACL-reconstructed knees with a hamstring graft. This partial restoration of normal kinematics may have a potential beneficial effect in patients recovering from ACL reconstruction with a hamstring autograft. Level III, case-control therapeutic study. Copyright �

Effects of prophylactic knee bracing on knee joint kinetics and kinematics during netball specific movements.

Science.gov (United States)

Sinclair, Jonathan K; Vincent, Hayley; Richards, Jim D

2017-01-01

To investigate the effects of a prophylactic knee brace on knee joint kinetics and kinematics during netball specific movements. Repeated measures. Laboratory. Twenty university first team level female netball players. Participants performed three movements, run, cut and vertical jump under two conditions (brace and no-brace). 3-D knee joint kinetics and kinematics were measured using an eight-camera motion analysis system. Knee joint kinetics and kinematics were examined using 2 × 3 repeated measures ANOVA whilst the subjective ratings of comfort and stability were investigated using chi-squared tests. The results showed no differences (p > 0.05) in knee joint kinetics. However the internal/external rotation range of motion was significantly (p < 0.05) reduced when wearing the brace in all movements. The subjective ratings of stability revealed that netballers felt that the knee brace improved knee stability in all movements. Further study is required to determine whether reductions in transverse plane knee range of motion serve to attenuate the risk from injury in netballers. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Application of Buckling Reinforced Bracing and Shear Wall in Retrofitting of Existing Concrete Building

Directory of Open Access Journals (Sweden)

Mahdi Izadi

2015-06-01

Full Text Available Vulnerable buildings and their rehabilitation are important problems for earthquake regions. In recent decades the goal of building rehabilitation and strengthening has gained different rehabilitation systems. However, most of these strengthening techniques disturb the occupants, who must vacate the building during renovation. Several retrofitting techniques such as addition masonry infill wall, application of buckling restrained braces and local modification of components has been studied in order to improve the overall seismic performance of such buildings. In response to many of the practical issues and economic considerations, engineers use often convergent unbuckling steel bracing frames as the lateral load resisting system during an earthquake.This kind of bracings increases the hardness and strength of concrete structures.The aim of the present study is the evaluation and comparison of seismic performance and retrofitting of an existing 7-storeys concrete structure with buckling restrained bracings and shear walls by nonlinear static procedure (NSP and accordance with cod-361. The results show that the buckling restrained bracing, decreased drift to acceptable levels and Structure behaves on the life safety of performance level.

Structure-guided mutational analysis reveals the functional requirements for product specificity of DOT1 enzymes.

Science.gov (United States)

Dindar, Gülcin; Anger, Andreas M; Mehlhorn, Christine; Hake, Sandra B; Janzen, Christian J

2014-11-12

DOT1 enzymes are conserved methyltransferases that catalyse the methylation of lysine 79 on histone H3 (H3K79). Most eukaryotes contain one DOT1 enzyme, whereas African trypanosomes have two homologues, DOT1A and DOT1B, with different enzymatic activities. DOT1A mediates mono- and dimethylation of H3K76, the homologue of H3K79 in other organisms, whereas DOT1B additionally catalyses H3K76 trimethylation. However, it is unclear how these different enzymatic activities are achieved. Here we employ a trypanosomal nucleosome reconstitution system and structure-guided homology modelling to identify critical residues within and outside the catalytic centre that modulate product specificity. Exchange of these residues transfers the product specificity from one enzyme to the other, and reveals the existence of distinct regulatory domains adjacent to the catalytic centre. Our study provides the first evidence that a few crucial residues in DOT1 enzymes are sufficient to catalyse methyl-state-specific reactions. These results might also have far-reaching consequences for the functional understanding of homologous enzymes in higher eukaryotes.

Seismic Response and Evaluation of SDOF Self-Centering Friction Damping Braces Subjected to Several Earthquake Ground Motions

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Jong Wan Hu

2015-01-01

Full Text Available This paper mainly deals with seismic response and performance for self-centering friction damping braces (SFDBs subjected to several maximum- or design-leveled earthquake ground motions. The self-centering friction damping brace members consist of core recentering components fabricated with superelastic shape memory alloy wires and energy dissipation devices achieved through shear friction mechanism. As compared to the conventional brace members for use in the steel concentrically braced frame structure, these self-centering friction damping brace members make the best use of their representative characteristics to minimize residual deformations and to withstand earthquake loads without member replacement. The configuration and response mechanism of self-centering friction damping brace systems are firstly described in this study, and then parametric investigations are conducted through nonlinear time-history analyses performed on numerical single degree-of-freedom spring models. After observing analysis results, adequate design methodologies that optimally account for recentering capability and energy dissipation according to their comparative parameters are intended to be suggested in order to take advantage of energy capacity and to minimize residual deformation simultaneously.

Supporting brace sizing in structures with added linear viscous fluid dampers: A filter design solution

OpenAIRE

Londono, J.M.; Wagg, D.; Neild, S.A.

2014-01-01

Viscous fluid dampers have proved to be effective in suppressing unwanted vibrations in a range of engineering structures. When dampers are fitted in a structure, a brace is typically used to attach them to the main structure. The stiffness of this brace can significantly alter the effectiveness of the damper, and in structures with multiple dampers, this can be a complex scenario to model. In this paper, we demonstrate that the effects of the brace compliance on the damper performance can be...

A Review of Influence of Various Types of Structural Bracing to the Structural Performance of Buildings

Science.gov (United States)

Razak, S. M.; Kong, T. C.; Zainol, N. Z.; Adnan, A.; Azimi, M.

2018-03-01

Excessive lateral drift can contribute significantly towards crack formation, leading to structural damage. The structural damage will in turn reduce the capacity of the structure and weaken it from the intended design capacity. Generally, lateral drift is more pronounced in higher and longer structure, such as high rise buildings and bridges. A typical method employed to control lateral drift is structural bracing, which works by increasing stiffness and stability of structure. This paper reviews the influence of various types of structural bracing to structural performance of buildings. The history of structural bracing is visited and the differences between numerous structural bracing in term of suitability to different types of buildings and loading, mechanisms, technical details, advantages and limitations, and the overall effect on the structural behaviour and performance are dissected. Proper and efficient structural bracing is pertinent for each high rise building as this will lead towards safer, sustainable and more economical buildings, which are cheaper to maintain throughout the life of the buildings in the future.

Isopiestic Investigation of the Osmotic and Activity Coefficients of {yMgCl2 + (1 - y)MgSO4}(aq) and the Osmotic Coefficients of Na2SO4.MgSO4(aq) at 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Miladinovic, J; Ninkovic, R; Todorovic, M; Rard, J A

2007-06-06

Isopiestic vapor pressure measurements were made for {l_brace}yMgCl{sub 2} + (1-y)MgSO{sub 4}{r_brace}(aq) solutions with MgCl{sub 2} ionic strength fractions of y = 0, 0.1997, 0.3989, 0.5992, 0.8008, and (1) at the temperature 298.15 K, using KCl(aq) as the reference standard. These measurements for the mixtures cover the ionic strength range I = 0.9794 to 9.4318 mol {center_dot} kg{sup -1}. In addition, isopiestic measurements were made with NaCl(aq) as reference standard for mixtures of {l_brace}xNa{sub 2}SO{sub 4} + (1-x)MgSO{sub 4}{r_brace}(aq) with the molality fraction x = 0.50000 that correspond to solutions of the evaporite mineral bloedite (astrakanite), Na{sub 2}Mg(SO{sub 4}){sub 2} {center_dot} 4H{sub 2}O(cr). The total molalities, m{sub T} = m(Na{sub 2}SO{sub 4}) + m(MgSO{sub 4}), range from m{sub T} = 1.4479 to 4.4312 mol {center_dot} kg{sup -1} (I = 5.0677 to 15.509 mol {center_dot} kg{sup -1}), where the uppermost concentration is the highest oversaturation molality that could be achieved by isothermal evaporation of the solvent at 298.15 K. The parameters of an extended ion-interaction (Pitzer) model for MgCl2(aq) at 298.15 K, which were required for an analysis of the {l_brace}yMgCl{sub 2} + (1-y)MgSO{sub 4}{r_brace}(aq) mixture results, were evaluated up to I = 12.025 mol {center_dot} kg{sup -1} from published isopiestic data together with the six new osmotic coefficients obtained in this study. Osmotic coefficients of {l_brace}yMgCl{sub 2} + (1-y)MgSO{sub 4}{r_brace}(aq) solutions from the present study, along with critically-assessed values from previous studies, were used to evaluate the mixing parameters of the extended ion-interaction model.

Delayed latency of peroneal reflex to sudden inversion with ankle taping or bracing.

Science.gov (United States)

Shima, N; Maeda, A; Hirohashi, K

2005-01-01

The purpose of the present study was to examine the effects of ankle taping and bracing based on the peroneal reflex in the hypermobile and normal ankle joints with and without history of ankle injury. Thirty-six ankle joints of 18 collegiate American football athletes with and without previous history of injury were studied. The angle of talar tilt (TT) was measured by stress radiograph for classifying normal (TT5 degrees ) ankles. They were tested with taping, bracing, and without any supports as a control. The latency of peroneus longus muscle was measured by a sudden inversion of 25 degrees using surface EMG signals. The results of the present study show no significant three-way Group (hypermobile or normal ankles) by History (previously injured or uninjured ankles) by Condition (control, taping, or bracing) interaction, while Condition main effect was significant (p0.05). In conclusion, ankle taping and bracing delayed the peroneal reflex latency not only for hypermobile ankles and/or injured ankle joints but also for intact ankle joints.

Engineering colloidal quantum dot solids within and beyond the mobility-invariant regime

KAUST Repository

Zhitomirsky, David

2014-05-06

© 2014 Macmillan Publishers Limited. Colloidal quantum dots are attractive materials for efficient, low-cost and facile implementation of solution-processed optoelectronic devices. Despite impressive mobilities (1-30 cm2V-1 s-1) reported for new classes of quantum dot solids, it is-surprisingly-the much lower-mobility (10-3-10-2 cm2V-1 s-1) solids that have produced the best photovoltaic performance. Here we show that it is not mobility, but instead the average spacing among recombination centres that governs the diffusion length of charges in today\\'s quantum dot solids. In this regime, colloidal quantum dot films do not benefit from further improvements in charge carrier mobility. We develop a device model that accurately predicts the thickness dependence and diffusion length dependence of devices. Direct diffusion length measurements suggest the solid-state ligand exchange procedure as a potential origin of the detrimental recombination centres. We then present a novel avenue for in-solution passivation with tightly bound chlorothiols that retain passivation from solution to film, achieving an 8.5% power conversion efficiency.

Comparison of in-and outpatients protocols for providence night time only bracing in AIS patients -- compliance and satisfaction

DEFF Research Database (Denmark)

Al-Aubaidi, Zaid Tj; Tropp, Hans; Pedersen, Niels W

2013-01-01

BACKGROUND: Skeletally immature patients diagnosed with adolescent idiopathic scoliosis (AIS) and a Cobb angle above 25degrees is usually treated with a brace. Standard protocols in many centers include hospitalisation for a few days for the purpose of brace adaptation and fitting. The aim...... of this study is to compare compliance and satisfaction in hospitalization and out patient clinic protocols, at the initiation phase of brace treatment.Materials and methodsTwenty-four consecutive patients with AIS were initiated with the Providence night time only brace at our department between October 2008...

Effects of Prophylactic Knee Bracing on Lower Limb Kinematics, Kinetics, and Energetics During Double-Leg Drop Landing at 2 Heights.

Science.gov (United States)

Ewing, Katie A; Begg, Rezaul K; Galea, Mary P; Lee, Peter V S

2016-07-01

Anterior cruciate ligament (ACL) injuries commonly occur during landing maneuvers. Prophylactic knee braces were introduced to reduce the risk of ACL injuries, but their effectiveness is debated. We hypothesized that bracing would improve biomechanical factors previously related to the risk of ACL injuries, such as increased hip and knee flexion angles at initial contact and at peak vertical ground-reaction force (GRF), increased ankle plantar flexion angles at initial contact, decreased peak GRFs, and decreased peak knee extension moment. We also hypothesized that bracing would increase the negative power and work of the hip joint and would decrease the negative power and work of the knee and ankle joints. Controlled laboratory study. Three-dimensional motion and force plate data were collected from 8 female and 7 male recreational athletes performing double-leg drop landings from 0.30 m and 0.60 m with and without a prophylactic knee brace. GRFs, joint angles, moments, power, and work were calculated for each athlete with and without a knee brace. Prophylactic knee bracing increased the hip flexion angle at peak GRF by 5.56° (P knee flexion angle at peak GRF by 4.75° (P = .001), and peak hip extension moment by 0.44 N·m/kg (P knee and ankle. No differences in peak GRFs and peak knee extension moment were observed with bracing. The application of a prophylactic knee brace resulted in improvements in important biomechanical factors associated with the risk of ACL injuries. Prophylactic knee braces may help reduce the risk of noncontact knee injuries in recreational and professional athletes while playing sports. Further studies should investigate different types of prophylactic knee braces in conjunction with existing training interventions so that the sports medicine community can better assess the effectiveness of prophylactic knee bracing. © 2016 The Author(s).

Forces exerted during exercises by patients with adolescent idiopathic scoliosis wearing fiberglass braces

OpenAIRE

Romano Michele; Carabalona Roberta; Petrilli Silvia; Sibilla Paolo; Negrini Stefano

2006-01-01

Abstract Objective To quantify and compare the forces exerted by scoliosis patients in fiberglass braces during exercises usually prescribed in departments where casts are made. The exercises are intended to increase corrective forces, activate muscles, stimulate ventilation and help the patient psychologically. Setting Outpatient care. Patients 17 consecutive adolescent patients wearing fiberglass brace for idiopathic scoliosis. Interventions Exercises (kyphotization, rotation, "escape from ...

Studies on the controlled growth of InAs nanostructures on scission surfaces; Untersuchungen zum kontrollierten Wachstum von InAs-Nanostrukturen auf Spaltflaechen

Energy Technology Data Exchange (ETDEWEB)

Bauer, J.

2006-01-15

The aim of this thesis was the controlled alignment of self-assembled InAs nano-structures on a {l_brace}110{r_brace}-oriented surface. The surface is prestructured with the atomic precision offered by molecular beam epitaxy, using the cleaved edge overgrowth-technique. On all samples grown within this work, the epitaxial template in the first growth step was deposited on a (001)GaAs substrate, while the InAs-layer forming the nanostructures during the second growth step was grown on cleaved {l_brace}110{r_brace}-GaAs surfaces. Atomic Force Microscopy (AFM) investigations demonstrate the formation of quantum dot (QD)-like nanostructures on top of the AlAs-stripes. X-ray diffraction measurements on large arrays of aligned quantum dots demonstrate that the quantum dots are formed of pure InAs. First investigations on the optical properties of these nanostructures were done using microphotoluminescence-spectroscopy with both high spatial and spectral resolution. (orig.)

A study of the x-irradiated Cs sub 5 H sub 3 (SO sub 4) sub 4 centre dot H sub 2 O crystal by EPR in the 80-415 K temperature range

CERN Document Server

Waplak, S; Baranov, A I; Shuvalov, L A

1997-01-01

The EPR spectra of the x-irradiated fast proton conductor Cs sub 5 H sub 3 (SO sub 4) sub 4 centre dot H sub 2 O were investigated in the temperature range of 80-415 K. Two kinds of paramagnetic SO sub 4 sup - centres with different proton configurations below about 370 K and freeze-out behaviour of one of them below about 200 K were observed. The role of acid proton dynamics with respect to the glassy-like transition is discussed. (author)

Ankle brace attenuates the medial-lateral ground reaction force during basketball rebound jump

Directory of Open Access Journals (Sweden)

Alex Castro

Full Text Available ABSTRACT Introduction: The jump landing is the leading cause for ankle injuries in basketball. It has been shown that the use of ankle brace is effective to prevent these injuries by increasing the mechanical stability of the ankle at the initial contact of the foot with the ground. Objective: To investigate the effects of ankle brace on the ground reaction force (GRF during the simulation of a basketball rebound jump. Method: Eleven young male basketball players randomly carried out a simulated basketball rebound jump under two conditions, with and without ankle brace (lace-up. Dynamic parameters of vertical GRF (take-off and landing vertical peaks, time to take-off and landing vertical peaks, take-off impulse peak, impulse at 50 milliseconds of landing, and jump height and medial-lateral (take-off and landing medial-lateral peaks, and time to reach medial-lateral peaks at take-off and landing were recorded by force platform during rebound jumps in each tested condition. The comparisons between the tested conditions were performed by paired t test (P0.05. Conclusion: The use of ankle brace during basketball rebound jumps attenuates the magnitude of medial-lateral GRF on the landing phase, without changing the vertical GRF. This finding indicates that the use of brace increases the medial-lateral mechanical protection by decreasing the shear force exerted on the athlete’s body without change the application of propulsive forces in the take-off and the impact absorption quality in the landing during the basketball rebound jump.

Rehabilitation of adolescent idiopathic scoliosis: results of exercises and bracing from a series of clinical studies. Europa Medicophysica-SIMFER 2007 Award Winner.

Science.gov (United States)

Negrini, S; Atanasio, S; Zaina, F; Romano, M

2008-06-01

Rehabilitation of adolescent idiopathic scoliosis (AIS) requires a careful choice from among the possible treatments, such as bracing and exercises, according to the patient's needs. According to the literature, there is little evidence regarding the efficacy of these rehabilitation instruments. During the past few years, a full series of studies has been carried out to investigate their efficacy. The aim of this paper was to summarize all these results. Three systematic reviews (two on exercises and one on manual therapy), and four cohort prospective studies were performed. The prospective studies included two trials with a prospective control group on exercises (one to avoid bracing and one in preparation to bracing) and two trials with retrospective control group on a new brace developed by the Authors (Sforzesco brace and SPoRT concept of correction versus Lyon brace and Risser cast). Results show that in literature there is proof of level 1b on exercises but no studies on manual therapy. High quality exercises like Scientific Exercises Approach to Scoliosis (SEAS) have more efficacy than usual physiotherapy, significantly reducing brace prescription in one year from 25% of cases to 6%. Moreover, such exercises help to obtain the best results in bracing first correction. The Sforzesco brace has proved to have more efficacy than the Lyon brace, whereas it has the same efficacy--but reduced side effects and impact on quality of life--than the Risser brace. With an efficient management of data collection, it is possible to develop a set of studies aimed at verifying the efficacy of clinical daily rehabilitation approaches.

Effect of Kınesıotapıng and Knee Brace on Functıonal Performance in Recreatıonal Athletes

Science.gov (United States)

Ulusoy, Burak; İldiz, Bülent; Tunay, Volga Bayrakçı

2014-01-01

Objectives: Kinesiotaping is a popular taping method that is used for both therapeutic and performance enchancement purposes. Knee braces are widely used for prevention in sport injuries but their performance effectiveness is still controversial. The aim of this study was to determine whether kinesiotape or brace was more effective on functional performance. Methods: A total twenty male recreational football players (Mean±Standart Deviation (SD) age: 22.5±0.68 years, height: 175.15±3.37 cm, body weight: 74.52±12.41 kg), voluntarily participated in this study. Participants were tested with kinesiotape, with brace and without kinesiotape and brace. Tests were applied one day after patellar kinesiotaping (correction technique). Balance property measured with Modified Y balance Test (dynamic test), agility measured by T test, muscle strength and anaerobic power assessed by vertical jump and triple hop tests. Wilcoxon signed rank test was employed for determining the statistical significance of tests with kinesiotape, with brace and without kinesiotape and brace. Results: In analysis; There were statistically significant differences found in Triple hop test with kinesiotaping and without kinesiotaping and brace, in T test with bracing and kinesiotaping, in vertical jump with kinesiotaping and without kinesiotaping and brace (pkinesiotaping in all tests) No statistically significant difference was found in modified Y balance test all groups (p> 0.05). Conclusion: Consequently, kinesiotaping had positive effects on agility and muscle strength but had no effects on balance in football players. On the other hand, brace had no effects on functional performance tests.

Application of different measures of skeletal maturity in initiating weaning from a brace for scoliosis: two case reports

Directory of Open Access Journals (Sweden)

Rivett LouAnn

2009-04-01

Full Text Available Abstract Introduction Various measures of skeletal maturity are used to initiate weaning from a brace in patients suffering from idiopathic scoliosis, resulting in different outcomes. We present two cases with double major curves, treated with the Rigo System Cheneau brace, and weaned using different criteria. Case presentation Case 1 was a South African, Caucasian girl who was initially treated with a brace at 14.75 years and who began weaning at 16.25 years on the basis of the Greulich and Pyle Index. She was out of her brace in 6 months, at least 11 months before reaching skeletal maturity as shown by the Risser Sign. Case 2 was a South African, Caucasian girl, initially treated with a brace at 14.25 years and who began the weaning process at 17.67 years on the basis of skeletal maturity according to the Risser Sign and static height for a period of 6 months. She was out of the brace 12 months later. In Case 1, the thoracic Cobb angle progressed during weaning and scoliometer readings deteriorated. The iliac apophysis fused 11 months after the wrist. In Case 2, the therapeutic gains made during the period of bracing were maintained during weaning, that is the improvement in the lumbar Cobb angle was maintained until the brace was removed, and scoliometer readings improved. The iliac apophysis fused 8.5 months after the wrist. Conclusions In patients with idiopathic scoliosis, it would seem to be more appropriate to base the timing of weaning on the Risser Sign and static height measurements rather than on traditional methods such as the Greulich and Pyle Index.

A Conceptual Design and Structural Analysis for ITER Mid-plane Brace Tools

Energy Technology Data Exchange (ETDEWEB)

Nam, Kyoung O; Park, Hyun Ki; Kim, Dong Jin [National Fusion Research Institute, Daejeon (Korea, Republic of); Lee, Jae Hyuk; Kim, Kyung kyu [SFA Engineering Corp., Changwon (Korea, Republic of); Im, Kihak; Robert, Shaw [ITER Organization, St Paul lez Durance Cedex (France)

2010-10-15

The ITER, International Thermonuclear Experimental Reactor, Tokamak machine is mainly composed of 9 vacuum vessel (VV)/toroidal field coils (TFCs)/vacuum vessel thermal shields (VVTS) 40 .deg. sectors. Each VV/TFCs/VVTS 40 .deg. sector is made up of one 40 .deg. VV, two 20 .deg. TFCs and associated VVTS segments. The ITER Tokamak assembly tools are purpose-built tools to assemble the ITER Tokamak machine which includes the cryostat and the components contained therein. Based on the design description document prepared by the IO (ITER international organization), Korea has carried out the conceptual design of assembly tools with IO cooperation. The 40 .deg. sector assemblies attached mid-plane brace tools sub-assembled at assembly hall are transferred to Tokamak hall using the lifting tool operated by Tokamak main cranes. The sector sub-assembly tools are composed of the upending tool, the sector sub-assembly tool, the sector lifting tool and the vacuum vessel support and mid-plane brace tools. The mid-plane brace tool is assembled to inner surface of VV and TFCs in phase of sector sub-assembly after completion of all sector components. VV, TFC and VVTS are separated fully before completion of 9 sectors at Tokamak in-pit. In this paper the mid-plane brace tools is introduced about function, structure and status of research and development are also described

Fluoroscopic Analysis of Tibial Translation in Anterior Cruciate Ligament Injured Knees With and Without Bracing During Forward Lunge

Science.gov (United States)

Jalali, Maryam; Farahmand, Farzam; Mousavi, Seyed Mohammad Ebrahim; Golestanha, Seyed Ali; Rezaeian, Tahmineh; Shirvani Broujeni, Shahram; Rahgozar, Mehdi; Esfandiarpour, Fateme

2015-01-01

Background: Despite several studies with different methods, the effect of functional knee braces on knee joint kinematics is not clear. Direct visualization of joint components through medical imaging modalities may provide the clinicians with more useful information. Objectives: In this study, for the first time in the literature, video fluoroscopy was used to investigate the effect of knee bracing on the sagittal plane kinematics of anterior cruciate ligament (ACL) injured patients. Patients and Methods: For twelve male unilateral ACL deficient subjects, the anterior tibial translation was measured during lunge exercise in non-braced and braced conditions. Fluoroscopic images were acquired from the subjects using a digital fluoroscopy system with a rate of 10 fps. The image of each frame was scaled using a calibration coin and analyzed in AutoCAD environment. The angle between the two lines, tangent to the posterior cortexes of the femoral and tibial shafts was measured as the flexion angle. For the fluoroscopic images associated with 0°, 15°, 30°, 45° and 60° knee flexion angles, the relative anterior-posterior configuration of the tibiofemoral joint was assessed by measuring the position of landmarks on the tibia and femur. Results: Results indicated that the overall anterior translations of the tibia during the eccentric (down) and concentric (up) phases of lunge exercise were 10.4 ± 1.7 mm and 9.0 ± 2.2 mm for non-braced, and 10.1 ± 3.4 mm and 7.4 ± 2.5 mm, for braced conditions, respectively. The difference of the tibial anterior-posterior translation behaviors of the braced and non-braced knees was not statistically significant. Conclusion: Fluoroscopic imaging provides an effective tool to measure the dynamic behavior of the knee joint in the sagittal plane and within the limitations of this study, the pure mechanical stabilizing effect of functional knee bracing is not sufficient to control the anterior tibial translation of the ACL deficient

Fluoroscopic Analysis of Tibial Translation in Anterior Cruciate Ligament Injured Knees With and Without Bracing During Forward Lunge.

Science.gov (United States)

Jalali, Maryam; Farahmand, Farzam; Mousavi, Seyed Mohammad Ebrahim; Golestanha, Seyed Ali; Rezaeian, Tahmineh; Shirvani Broujeni, Shahram; Rahgozar, Mehdi; Esfandiarpour, Fateme

2015-07-01

Despite several studies with different methods, the effect of functional knee braces on knee joint kinematics is not clear. Direct visualization of joint components through medical imaging modalities may provide the clinicians with more useful information. In this study, for the first time in the literature, video fluoroscopy was used to investigate the effect of knee bracing on the sagittal plane kinematics of anterior cruciate ligament (ACL) injured patients. For twelve male unilateral ACL deficient subjects, the anterior tibial translation was measured during lunge exercise in non-braced and braced conditions. Fluoroscopic images were acquired from the subjects using a digital fluoroscopy system with a rate of 10 fps. The image of each frame was scaled using a calibration coin and analyzed in AutoCAD environment. The angle between the two lines, tangent to the posterior cortexes of the femoral and tibial shafts was measured as the flexion angle. For the fluoroscopic images associated with 0°, 15°, 30°, 45° and 60° knee flexion angles, the relative anterior-posterior configuration of the tibiofemoral joint was assessed by measuring the position of landmarks on the tibia and femur. Results indicated that the overall anterior translations of the tibia during the eccentric (down) and concentric (up) phases of lunge exercise were 10.4 ± 1.7 mm and 9.0 ± 2.2 mm for non-braced, and 10.1 ± 3.4 mm and 7.4 ± 2.5 mm, for braced conditions, respectively. The difference of the tibial anterior-posterior translation behaviors of the braced and non-braced knees was not statistically significant. Fluoroscopic imaging provides an effective tool to measure the dynamic behavior of the knee joint in the sagittal plane and within the limitations of this study, the pure mechanical stabilizing effect of functional knee bracing is not sufficient to control the anterior tibial translation of the ACL deficient patients during lunge exercise.

The predictive value of the extensor grip test for the effectiveness of bracing for tennis elbow

NARCIS (Netherlands)

Struijs, Peter A. A.; Assendelft, Willem J. J.; Kerkhoffs, Gino M. M. J.; Souer, Sebastiaan; van Dijk, C. Niek

2005-01-01

Background: Tennis elbow is a common complaint. Several treatment strategies, such as corticosteroid injections and physical therapy and braces, have been described. Hypothesis: The extensor grip test has predictive value in assessing the effectiveness of bracing in tennis elbow. Study Design:

Evaluation of Brace Treatment for Infant Hip Dislocation in a Prospective Cohort: Defining the Success Rate and Variables Associated with Failure.

Science.gov (United States)

Upasani, Vidyadhar V; Bomar, James D; Matheney, Travis H; Sankar, Wudbhav N; Mulpuri, Kishore; Price, Charles T; Moseley, Colin F; Kelley, Simon P; Narayanan, Unni; Clarke, Nicholas M P; Wedge, John H; Castañeda, Pablo; Kasser, James R; Foster, Bruce K; Herrera-Soto, Jose A; Cundy, Peter J; Williams, Nicole; Mubarak, Scott J

2016-07-20

The use of a brace has been shown to be an effective treatment for hip dislocation in infants; however, previous studies of such treatment have been single-center or retrospective. The purpose of the current study was to evaluate the success rate for brace use in the treatment of infant hip dislocation in an international, multicenter, prospective cohort, and to identify the variables associated with brace failure. All dislocations were verified with use of ultrasound or radiography prior to the initiation of treatment, and patients were followed prospectively for a minimum of 18 months. Successful treatment was defined as the use of a brace that resulted in a clinically and radiographically reduced hip, without surgical intervention. The Mann-Whitney test, chi-square analysis, and Fisher exact test were used to identify risk factors for brace failure. A multivariate logistic regression model was used to determine the probability of brace failure according to the risk factors identified. Brace treatment was successful in 162 (79%) of the 204 dislocated hips in this series. Six variables were found to be significant risk factors for failure: developing femoral nerve palsy during brace treatment (p = 0.001), treatment with a static brace (p failure, whereas hips with 4 or 5 risk factors had a 100% probability of failure. These data provide valuable information for patient families and their providers regarding the important variables that influence successful brace treatment for dislocated hips in infants. Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.

Effect of a patella support brace on myoelectric activity of knee joint muscles during single leg landing

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Fatemeh Salariesker

2013-06-01

Full Text Available Introduction: Patellfemoral pain syndrome is one of the most common knee joint problems that affect athletes and non-athletes. Knee brace is often used as a treatment method for patellar realignment. The aim of the present study was to determine the effects of a patella support brace on myoelectric activity of selected knee muscles during single leg landing in healthy females. Materials and Methods: 19 healthy female students (Mean age: 23.6±1.98 years, height: 163.5±5.88 cm, weight: 62.3±3.6 kg participated in this study. Myoelectric activity of biceps femoris, semitendinosus, vastus medialis and vastus lateralis were collected during single leg landing in with and without using the patella support brace conditions.Results: Use of the patella support brace had no significant effect on myoelectric activity for the semitendinosus (p=0.668, vastus medialis (VM (p=0.915 and vastus lateralis (VL (P=0.134, while myoelectric activity for biceps femoris (p=0.005 and ratio of VM/VL myoelectric activity significantly increased (p=0.045. Conclusion: Our results revealed that biceps femoris activity and vastus medialis/vastus lateralis ratio increased after using patella support brace during single leg landing. Further studies on kinematic and kinetic variables are needed to describe these changes in muscular activity when using the patella support brace.

Structural analysis: Flexible receiver yoke brace for the 241SY101 mixer pump

International Nuclear Information System (INIS)

Jones, K.M.

1994-01-01

This report documents the structural analysis of the flexible-receiver yoke brace that will be used to maintain the mixer pump lifting yoke in a vertical position during the removal of the mixer pump from waste tank 241SY101. During the removal process, the crane is connected to a lifting yoke which is attached to the lifting on the mounting flange of the mixer pump. The pump then can be lifted from the tank. At one point in the removal procedure, the crane will be disconnected from the lifting yoke. At this time, it is possible for the lifting yoke to rotate around the pinned connection between it and the pump if it is subjected to a horizontal load. To prevent the rotation of the lifting yoke, the yoke brace was designed to maintain the yoke in a vertical position while it is disconnected from the crane. This analysis addressed the adequacy of the yoke brace to provide support for the lifting yoke during high winds and a seismic event. The results of this analysis show that, when subjected to a combined design wind and seismic load, the yoke brace design is acceptable to maintain the lifting yoke in a vertical position when the yoke is disconnected from the crane

Mechanical stability of the subtalar joint after lateral ligament sectioning and ankle brace application: a biomechanical experimental study.

Science.gov (United States)

Kamiya, Tomoaki; Kura, Hideji; Suzuki, Daisuke; Uchiyama, Eiichi; Fujimiya, Mineko; Yamashita, Toshihiko

2009-12-01

The roles of each ligament supporting the subtalar joint have not been clarified despite several biomechanical studies. The effects of ankle braces on subtalar instability have not been shown. The ankle brace has a partial effect on restricting excessive motion of the subtalar joint. Controlled laboratory study. Ten normal fresh-frozen cadaveric specimens were used. The angular motions of the talus were measured via a magnetic tracking system. The specimens were tested while inversion and eversion forces, as well as internal and external rotation torques, were applied. The calcaneofibular ligament, cervical ligament, and interosseous talocalcaneal ligament were sectioned sequentially, and the roles of each ligament, as well as the stabilizing effects of the ankle brace, were examined. Complete sectioning of the ligaments increased the angle between the talus and calcaneus in the frontal plane to 51.7 degrees + or - 11.8 degrees compared with 35.7 degrees + or - 6.0 degrees in the intact state when inversion force was applied. There was a statistically significant difference in the angles between complete sectioning of the ligaments and after application of the brace (34.1 degrees + or - 7.3 degrees ) when inversion force was applied. On the other hand, significant differences in subtalar rotation were not found between complete sectioning of the ligaments and application of the brace when internal and external rotational torques were applied. The ankle brace limited inversion of the subtalar joint, but it did not restrict motion after application of internal or external rotational torques. In cases of severe ankle sprains involving the calcaneofibular ligament, cervical ligament, and interosseous talocalcaneal ligament injuries, application of an ankle brace might be less effective in limiting internal-external rotational instabilities than in cases of inversion instabilities in the subtalar joint. An improvement in the design of the brace is needed to restore

A systematic review on the treatment of acute ankle sprain: brace versus other functional treatment types.

Science.gov (United States)

Kemler, Ellen; van de Port, Ingrid; Backx, Frank; van Dijk, C Niek

2011-03-01

Ankle injuries, especially ankle sprains, are a common problem in sports and medical care. Ankle sprains result in pain and absenteeism from work and/or sports participation, and can lead to physical restrictions such as ankle instability. Nowadays, treatment of ankle injury basically consists of taping the ankle. The purpose of this review is to evaluate the effectiveness of ankle braces as a treatment for acute ankle sprains compared with other types of functional treatments such as ankle tape and elastic bandages. A computerized literature search was conducted using PubMed, EMBASE, CINAHL and the Cochrane Clinical Trial Register. This review includes randomized controlled trials in English, German and Dutch, published between 1990 and April 2009 that compared ankle braces as a treatment for lateral ankle sprains with other functional treatments. The inclusion criteria for this systematic review were (i) individuals (sports participants as well as non-sports participants) with an acute injury of the ankle (acute ankle sprains); (ii) use of an ankle brace as primary treatment for acute ankle sprains; (iii) control interventions including any other type of functional treatment (e.g. Tubigrip™, elastic wrap or ankle tape); and (iv) one of the following reported outcome measures: re-injuries, symptoms (pain, swelling, instability), functional outcomes and/or time to resumption of sports, daily activities and/or work. Eight studies met all inclusion criteria. Differences in outcome measures, intervention types and patient characteristics precluded pooling of the results, so best evidence syntheses were conducted. A few individual studies reported positive outcomes after treatment with an ankle brace compared with other functional methods, but our best evidence syntheses only demonstrated a better treatment result in terms of functional outcome. Other studies have suggested that ankle brace treatment is a more cost-effective method, so the use of braces after acute

Do Knee Bracing and Delayed Weight Bearing Affect Mid-Term Functional Outcome after Anterior Cruciate Ligament Reconstruction?

Science.gov (United States)

Di Miceli, Riccardo; Marambio, Carlotta Bustos; Zati, Alessandro; Monesi, Roberta; Benedetti, Maria Grazia

2017-12-01

Purpose  The aim of this study was to assess the effect of knee bracing and timing of full weight bearing after anterior cruciate ligament reconstruction (ACLR) on functional outcomes at mid-term follow-up. Methods  We performed a retrospective study on 41 patients with ACLR. Patients were divided in two groups: ACLR group, who received isolated ACL reconstruction and ACLR-OI group who received ACL reconstruction and adjunctive surgery. Information about age at surgery, bracing, full or progressive weight bearing permission after surgery were collected for the two groups. Subjective IKDC score was obtained at follow-up. Statistical analysis was performed to compare the two groups for IKDC score. Subgroup analysis was performed to assess the effect of postoperative regimen (knee bracing and weight bearing) on functional outcomes. Results  The mean age of patients was 30.8 ± 10.6 years. Mean IKDC score was 87.4 ± 13.9. The mean follow-up was 3.5 ± 1.8 years. Twenty-two (53.7%) patients underwent ACLR only, while 19 (46.3%) also received other interventions, such as meniscal repair and/or collateral ligament suture. Analysis of overall data showed no differences between the groups for IKDC score. Patients in the ACLR group exhibited a significantly better IKDC score when no brace and full weight bearing after 4 weeks from surgery was prescribed in comparison with patients who worn a brace and had delayed full weight bearing. No differences were found with respect to the use of brace and postoperative weight bearing regimen in the ACLR-OI group. Conclusion  Brace and delayed weight bearing after ACLR have a negative influence on long-term functional outcomes. Further research is required to explore possible differences in the patients operated on ACLR and other intervention with respect to the use of a brace and the timing of full weight bearing to identify optimal recovery strategies. Level of Evidence  Level III, retrospective observational

Long-term results after Boston brace treatment in late-onset juvenile and adolescent idiopathic scoliosis

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Gunderson Ragnhild

2011-08-01

Full Text Available Abstract Background It is recommended that research in patients with idiopathic scoliosis should focus on short- and long-term patient-centred outcome. The aim of the present study was to evaluate outcome in patients with late-onset juvenile or adolescent idiopathic scoliosis 16 years or more after Boston brace treatment. Methods 272 (78% of 360 patients, 251 (92% women, responded to follow-up examination at a mean of 24.7 (range 16 - 32 years after Boston brace treatment. Fifty-eight (21% patients had late-onset juvenile and 214 had adolescent idiopathic scoliosis. All patients had clinical and radiological examination and answered a standardised questionnaire including work status, demographics, General Function Score (GFS (100 - worst possible and Oswestry Disability Index (ODI (100 - worst possible, EuroQol (EQ-5D (1 - best possible, EQ-VAS (100 - best possible, and Scoliosis Research Society - 22 (SRS - 22 (5 - best possible. Results The mean age at follow-up was 40.4 (31-48 years. The prebrace major curve was in average 33.2 (20 - 57°. At weaning and at the last follow-up the corresponding values were 28.3 (1 - 58° and 32.5 (7 - 80°, respectively. Curve development was similar in patients with late-onset juvenile and adolescent start. The prebrace curve increased > 5° in 31% and decreased > 5° in 26%. Twenty-five patients had surgery. Those who did not attend follow-up (n = 88 had a lower mean curve at weaning: 25.4 (6-53°. Work status was 76% full-time and 10% part-time. Eighty-seven percent had delivered a baby, 50% had pain in pregnancy. The mean (SD GFS was 7.4 (10.8, ODI 9.3 (11.0, EQ-5D 0.82 (0.2, EQ-VAS 77.6 (17.8, SRS-22: pain 4.1 (0.8, mental health 4.1 (0.6, self-image 3.7 (0.7, function 4.0 (0.6, satisfaction with treatment 3.7 (1.0. Surgical patients had significantly reduced scores for SRS-physical function and self-image, and patients with curves ≥ 45° had reduced self-image. Conclusion Long-term results were

SOSORT Award Winner 2015: a multicentre study comparing the SPoRT and ART braces effectiveness according to the SOSORT-SRS recommendations.

Science.gov (United States)

Zaina, Fabio; de Mauroy, Jean Claude; Donzelli, Sabrina; Negrini, Stefano

2015-01-01

Data comparing different braces for adolescent idiopathic scoliosis (AIS) are scant. The SRS criteria represent some guidelines for comparing results from different studies, but controlled studies are much more reliable. Recently, super-rigid braces have been introduced in clinical practice with the aim of replacing Risser and EDF casts. The aim of the present study is to compare the short-term radiographic results of two super-rigid braces, the ART and the SPORT (Sforzesco) brace. A group of consecutive patients with Cobb >40°, Risser 0-4, age >10 treated with the ART brace for 6 months were matched with a group of similar patients taken from a prospective database of patients treated with the Sforzesco brace. Patients were matched according to Cobb severity, pattern and localization of the curve. All patients had a full-time brace prescription (23-24 hours per day) and an indication to perform scoliosis-specific exercises and were assessed radiographically both immediately in the brace and after 6 months of treatment out of brace. Curves were analyzed according to the pattern and localization taking into consideration both the in-brace correction and the 6-month out-of-brace results. t-test, ANOVA, linear regression, alpha set at 0.05. Twenty-six patients were included in the ART brace group, and 26 in the Sforzesco brace group. At baseline, no differences were noted for gender (3 males for each group), age (14.1 ± 0.3 for ART vs 13.9 ± 0.3 for Sforzesco), ATR (11.8 ± 3.2 vs 11.5 ± 4.2 for thoracic curves and 7.8 ± 4.0 vs 7.1 ± 6.1 for lumbar/thoracolumbar), Cobb angle (44.8 ± 2 vs 45.5 ± 2 for thoracic; 43.8 ± 2 vs 46.0 ± 2 for lumbar/thoracolumbar) or Risser sign (median 2 for both groups). The in-brace correction was slightly better for the ART brace, but didn't reach statistical significance (24.3 ± 8.5 vs 28.0 ± 6.8 for thoracic; 23.7 ± 10.4 vs 29.9 ± 4.2 for lumbar/thoracolumbar). At 6�

An Experimental Study on Hybrid Noncompression CF Bracing and GF Sheet Wrapping Reinforcement Method to Restore Damaged RC Structures

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Kang Seok Lee

2015-01-01

Full Text Available We describe a novel technique for restoration of reinforced concrete (RC structures that have sustained damage during an earthquake. The reinforcement scheme described here is a hybrid seismic retrofitting technique that combines noncompression X-bracing using CF with externally bonded GF sheets to strengthen RC structures that have sustained damage following an earthquake. The GF sheet is used to improve the ductility of columns, and the noncompression CF X-bracing system, which consists of CF bracing and anchors to replace the conventional steel bracing and bolt connections, is used to increase the lateral strength of the framing system. We report seismic restoration capacity, which enables reuse of the damaged RC frames via the hybrid CF X-bracing and GF sheet wrapping system. Cyclic loading tests were carried out to investigate hysteresis of the lateral load-drift relations, as well as the ductility. The GF sheet significantly improved the ductility of columns, resulting in a change in failure mode. The strengthening effect of conventional CF sheets used in columns is not sufficient with respect to lateral strength and stiffness. However, this study results in a significant increase in the strength of the structure due to the use of CF X-bracing and inhibited buckling failure of the bracing. This result can be exploited to develop guidelines for the application of the reinforcement system to restore damaged RC structures.

Complex dynamics in planar two-electron quantum dots

International Nuclear Information System (INIS)

Schroeter, Sebastian Josef Arthur

2013-01-01

Quantum dots play an important role in a wide range of recent experimental and technological developments. In particular they are promising candidates for realisations of quantum bits and further applications in quantum information theory. The harmonically confined Hooke's atom model is experimentally verified and separates in centre-of-mass and relative coordinates. Findings that are contradictory to this separability call for an extension of the model, in particular changing the confinement potential. In order to study effects of an anharmonic confinement potential on spectral properties of planar two-electron quantum dots a sophisticated numerical approach is developed. Comparison between the Helium atom, Hooke's atom and an anharmonic potential model are undertaken in order to improve the description of quantum dots. Classical and quantum features of complexity and chaos are investigated and used to characterise the dynamics of the system to be mixed regular-chaotic. Influence of decoherence can be described by quantum fidelity, which measures the effect of a perturbation on the time evolution. The quantum fidelity of eigenstates of the system depends strongly on the properties of the perturbation. Several methods for solving the time-dependent Schrödinger equation are implemented and a high level of accuracy for long time evolutions is achieved. The concept of offset entanglement, the entanglement of harmonic models in the noninteracting limit, is introduced. This concept explains different questions raised in the literature for harmonic quantum dot models, recently. It shows that only in the groundstate the electrons are not entangled in the fermionic sense. The applicability, validity, and origin of Hund's first rule in general quantum dot models is further addressed. In fact Hund's first rule is only applicable, and in this case also valid, for one pair of singlet and triplet states in Hooke's atom. For more realistic models of two-electron quantum dots an

Thermal Behavior of Cylindrical Buckling Restrained Braces at Elevated Temperatures

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Elnaz Talebi

2014-01-01

Full Text Available The primary focus of this investigation was to analyze sequentially coupled nonlinear thermal stress, using a three-dimensional model. It was meant to shed light on the behavior of Buckling Restraint Brace (BRB elements with circular cross section, at elevated temperature. Such bracing systems were comprised of a cylindrical steel core encased in a strong concrete-filled steel hollow casing. A debonding agent was rubbed on the core’s surface to avoid shear stress transition to the restraining system. The numerical model was verified by the analytical solutions developed by the other researchers. Performance of BRB system under seismic loading at ambient temperature has been well documented. However, its performance in case of fire has yet to be explored. This study showed that the failure of brace may be attributed to material strength reduction and high compressive forces, both due to temperature rise. Furthermore, limiting temperatures in the linear behavior of steel casing and concrete in BRB element for both numerical and analytical simulations were about 196°C and 225°C, respectively. Finally it is concluded that the performance of BRB at elevated temperatures was the same as that seen at room temperature; that is, the steel core yields prior to the restraining system.

Thermal behavior of cylindrical buckling restrained braces at elevated temperatures.

Science.gov (United States)

Talebi, Elnaz; Tahir, Mahmood Md; Zahmatkesh, Farshad; Yasreen, Airil; Mirza, Jahangir

2014-01-01

The primary focus of this investigation was to analyze sequentially coupled nonlinear thermal stress, using a three-dimensional model. It was meant to shed light on the behavior of Buckling Restraint Brace (BRB) elements with circular cross section, at elevated temperature. Such bracing systems were comprised of a cylindrical steel core encased in a strong concrete-filled steel hollow casing. A debonding agent was rubbed on the core's surface to avoid shear stress transition to the restraining system. The numerical model was verified by the analytical solutions developed by the other researchers. Performance of BRB system under seismic loading at ambient temperature has been well documented. However, its performance in case of fire has yet to be explored. This study showed that the failure of brace may be attributed to material strength reduction and high compressive forces, both due to temperature rise. Furthermore, limiting temperatures in the linear behavior of steel casing and concrete in BRB element for both numerical and analytical simulations were about 196°C and 225°C, respectively. Finally it is concluded that the performance of BRB at elevated temperatures was the same as that seen at room temperature; that is, the steel core yields prior to the restraining system.

Informed consent for braces.

Science.gov (United States)

Jharwal, Vikas; Trehan, Mridula; Rathore, Nidhi; Rathee, Pooja; Agarwal, Deepesh; Mathur, Nikunj

2014-05-01

The influence of law on the orthodontic profession has greatly increased in the last few decades. Dental law has emerged today as a full-fedged specialty dealing with a variety of areas, like professional negligence, doctor-patient contracts, consumer protection laws, ethics, general and special health legislations and practice regulatory mechanisms. This article highlights the concept of informed consent which is based on the premise that each individual has a right to make decisions concerning his health, disease and treatment. How to cite this article: Jharwal V, Trehan M, Rathore N, Rathee P, Agarwal D, Mathur N. Informed Consent for Braces. Int J Clin Pediatr Dent 2014;7(2):105-108.

Detorsion night-time bracing for the treatment of early onset idiopathic scoliosis.

Science.gov (United States)

Moreau, S; Lonjon, G; Mazda, K; Ilharreborde, B

2014-12-01

Management for early onset scoliosis has recently changed, with the development of new surgical procedures. However, multiple surgeries are often required and high complication rates are still reported. Conservative management remains an alternative, serial casting achieving excellent results in young children. Better compliance and improvement over natural history have been reported with night-time bracing in adolescent idiopathic scoliosis (AIS), but this treatment has never been reported in early onset idiopathic scoliosis (EIOS). All patients treated for progressive EOIS by detorsion night-time bracing (DNB), and meeting the Scoliosis Research Society (SRS) criteria for brace studies were reviewed. Recommendations were given to wear the DNB 8h/night and no restriction was given regarding sports activities. Radiological parameters were compared between referral and latest follow-up. Based on the SRS criteria defined for AIS, a similar classification was used as follows to analyze the course of the curves: success group: patients with a progression of 5° or less; unsuccess group (progression or failure): patients with a progression>5°, patients with curves exceeding 45° at maturity, or who have had recommendation for/undergone surgery, or patients who changed orthopaedic treatment, or who were lost to follow-up. Thirty-three patients were included (21 girls and 12 boys), with a median Cobb angle of 31° (Q1-Q3: 22-40). Age at brace initiation averaged 50months (Q1-Q3: 25-60). Median follow-up was 102-months (Q1-Q3: 63-125). Fifteen patients (45.5%) had reached skeletal maturity at last follow-up. The success rate was 67% (22 patients), with a median Cobb angle reduction of 15° (P<0.001). Four patients stopped DNB due to an important regression. Eleven patients were in the unsuccessful group (33%). Only one had surgery. All patients remained balanced in the frontal plane and normokyphotic. Initial curve magnitude and age at brace initiation appeared to be

Complete quantum control of exciton qubits bound to isoelectronic centres.

Science.gov (United States)

Éthier-Majcher, G; St-Jean, P; Boso, G; Tosi, A; Klem, J F; Francoeur, S

2014-05-30

In recent years, impressive demonstrations related to quantum information processing have been realized. The scalability of quantum interactions between arbitrary qubits within an array remains however a significant hurdle to the practical realization of a quantum computer. Among the proposed ideas to achieve fully scalable quantum processing, the use of photons is appealing because they can mediate long-range quantum interactions and could serve as buses to build quantum networks. Quantum dots or nitrogen-vacancy centres in diamond can be coupled to light, but the former system lacks optical homogeneity while the latter suffers from a low dipole moment, rendering their large-scale interconnection challenging. Here, through the complete quantum control of exciton qubits, we demonstrate that nitrogen isoelectronic centres in GaAs combine both the uniformity and predictability of atomic defects and the dipole moment of semiconductor quantum dots. This establishes isoelectronic centres as a promising platform for quantum information processing.

Effectiveness of Treatment of Idiopathic Scoliosis by SpineCor Dynamic Bracing with Special Physiotherapy Programme in SpineCor System.

Science.gov (United States)

Rożek, Karina; Potaczek, Tomasz; Zarzycka, Maja; Lipik, Ewa; Jasiewicz, Barbara

2016-10-28

The SpineCor dynamic brace for the treatment of idiopathic scoliosis is designed to maintain the correct position of the spine and a new movement strategy for 20 hours per day. The SpineCor exercise system intensifies and complements the brace treatment. This study evaluated the effectiveness of a comprehensive treatment of idiopathic scoliosis involving the SpineCor system. The study assessed a group of 40 patients (38 girls and 2 boys) with idiopathic scoliosis treated with the SpineCor brace. The average age at beginning of treatment was 13.1 yrs (10-15). Minimum treatment time was 18 months. 28 participants met the SRS criteria. Angles of the curve before and after bracing based on imaging studies were measured at the beginning and end of the treatment, analyzed and compared. Rehabilitation focused on teaching active corrective movement throughout the brace treatment. A control group was formed of 33 patients, including 21 meeting the SRS criteria, who used the SpineCor dynamic brace but did not participate in the associated exercise programme. Among patients from the exercise group who met the SRS criteria, 25% demonstrated reduced curve angles, 35.7% demonstrated curve progression and 39.3% showed stabilization (no change). Among patients meeting the SRS criteria from the control group, a decrease in curve angle was observed in 14.3% of the patients, curve progression in 57.1% and stabilization in 28.6%. 1. The addition of a dedicated physiotherapy programme to SpineCor dynamic bracing improves the chances of obtaining a positive outcome. 2. It is necessary to further analyse the course of the comprehensive treatment, also with regard to other types of braces and kinesiotherapy programmes.

Displacement-Based Seismic Design Procedure for Framed Buildings with Dissipative Braces Part II: Numerical Results

International Nuclear Information System (INIS)

Mazza, Fabio; Vulcano, Alfonso

2008-01-01

For a widespread application of dissipative braces to protect framed buildings against seismic loads, practical and reliable design procedures are needed. In this paper a design procedure based on the Direct Displacement-Based Design approach is adopted, assuming the elastic lateral storey-stiffness of the damped braces proportional to that of the unbraced frame. To check the effectiveness of the design procedure, presented in an associate paper, a six-storey reinforced concrete plane frame, representative of a medium-rise symmetric framed building, is considered as primary test structure; this structure, designed in a medium-risk region, is supposed to be retrofitted as in a high-risk region, by insertion of diagonal braces equipped with hysteretic dampers. A numerical investigation is carried out to study the nonlinear static and dynamic responses of the primary and the damped braced test structures, using step-by-step procedures described in the associate paper mentioned above; the behaviour of frame members and hysteretic dampers is idealized by bilinear models. Real and artificial accelerograms, matching EC8 response spectrum for a medium soil class, are considered for dynamic analyses

Ankle Bracing, Fatigue, and Time to Stabilization in Collegiate Volleyball Athletes

Science.gov (United States)

Shaw, Megan Y; Gribble, Phillip A; Frye, Jamie L

2008-01-01

Context: Fatigue has been shown to disrupt dynamic stability in healthy volunteers. It is not known if wearing prophylactic ankle supports can improve dynamic stability in fatigued athletes. Objective: To determine the type of ankle brace that may be more effective at providing dynamic stability after a jump-landing task during normal and fatigued conditions. Design: Two separate repeated-measures analyses of variance with 2 within-subjects factors (condition and time) were performed for each dependent variable. Setting: Research laboratory. Patients or Other Participants: Ten healthy female collegiate volleyball athletes participated (age  =  19.5 ± 1.27 years, height  =  179.07 ± 7.6 cm, mass  =  69.86 ± 5.42 kg). Intervention(s): Athletes participated in 3 separate testing sessions, applying a different bracing condition at each session: no brace (NB), Swede-O Universal lace-up ankle brace (AB), and Active Ankle brace (AA). Three trials of a jump-landing task were performed under each condition before and after induced functional fatigue. The jump-landing task consisted of a single-leg landing onto a force plate from a height equivalent to 50% of each participant's maximal jump height and from a starting position 70 cm from the center of the force plate. Main Outcome Measure(s): Time to stabilization in the anterior-posterior (APTTS) and medial-lateral (MLTTS) directions. Results: For APTTS, a condition-by-time interaction existed (F2,18  =  5.55, P  =  .013). For the AA condition, Tukey post hoc testing revealed faster pretest (2.734 ± 0.331 seconds) APTTS than posttest (3.817 ± 0.263 seconds). Post hoc testing also revealed that the AB condition provided faster APTTS (2.492 ± 0.271 seconds) than AA (3.817 ± 0.263 seconds) and NB (3.341 ± 0.339 seconds) conditions during posttesting. No statistically significant findings were associated with MLTTS. Conclusions: Fatigue increased APTTS for the AA condition. Because the

Peculiarity of component interaction in {l_brace}Y, Dy{r_brace}-Mn-Sn ternary systems

Energy Technology Data Exchange (ETDEWEB)

Romaka, V.V. [Department of Materials Engineering and Applied Physics, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Konyk, M. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Romaka, L., E-mail: romakal@franko.lviv.ua [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Pavlyuk, V. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Jan Dlugosz University, Institute of Chemistry, Environmental Protection and Biotechnology, al. Armii Krajowej 13/15, 42200 Czestochowa (Poland); Ehrenberg, H. [Institute for Complex Materials, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden (Germany); Tkachuk, A. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine)

2011-07-14

Highlights: > {l_brace}Y, Dy{r_brace}-Mn-Sn ternary systems at 770 K are characterized by formation of stannides with general compositions RMn{sub 6}Sn{sub 6} and R{sub 4}Mn{sub 4}Sn{sub 7}. > The crystal structure of YMn{sub 6}Sn{sub 6} was determined by single crystal and powder diffraction methods. > Structural analysis showed that Dy{sub 4}Mn{sub 4}Sn{sub 7} compound is disordered. > Isostructural R{sub 4}Mn{sub 4}Sn{sub 7} compounds were also found with Gd, Tb, Ho, Er, Tm(confirmed), Yb, and Lu. - Abstract: The phase equilibria in the Y-Mn-Sn and Dy-Mn-Sn ternary systems were studied at 770 K by means of X-ray and metallographic analyses in the whole concentration range. Both Y-Mn-Sn and Dy-Mn-Sn systems are characterized by formation of two ternary compounds RMn{sub 6}Sn{sub 6} (MgFe{sub 6}Ge{sub 6}-type, space group P6/mmm) and R{sub 4}Mn{sub 4}Sn{sub 7} (Zr{sub 4}Co{sub 4}Ge{sub 7}-type, space group I4/mmm). The disorder in Dy{sub 4}Mn{sub 4}Sn{sub 7} compound was found by single crystal method. Compounds with the same type of structure were also found with Gd, Tb, Ho, Er, Tm (confirmed), Yb, and Lu and their lattice parameters were determined.

Body Image and Quality-of-Life in Untreated Versus Brace-Treated Females With Adolescent Idiopathic Scoliosis.

Science.gov (United States)

Schwieger, Traci; Campo, Shelly; Weinstein, Stuart L; Dolan, Lori A; Ashida, Sato; Steuber, Keli R

2016-02-01

The Bracing in Adolescent Idiopathic Scoliosis Trial (BrAIST) included skeletally immature high-risk patients with adolescent idiopathic scoliosis (AIS) with moderate curve sizes (20°- 40°). BrAIST was a multicenter, controlled trial using both randomized and preference treatment arms into either an observation group or a brace treatment group. The aim of this study was to analyze and compare body image and quality-of-life (QOL) in female AIS patients who were observed or treated with a brace. Brace treatment is an effective means for controlling progressive scoliosis and preventing the need for surgery, but there is no consensus regarding the effect of brace treatment on body image or on QOL in adolescents with AIS. Data from female BrAIST patients in the randomized (n = 132) or preference (n = 187) arms and were observed (n = 120) or brace treated (n = 199) were analyzed. Patients completed the Spinal Appearance Questionnaire (SAQ) and the Pediatric Quality of Life Inventory (PedsQOL) 4.0 Generic Scales at baseline and 6 month follow-up visits up to 2 years. Items on the SAQ measured three body image constructs (self, ideal, and overall). The PedsQOL measured health, activities, feelings, social factors, and school. . In general, there were no significant differences within or between study arms or treatments regarding body image or QOL through 2 years of follow-up. Poorer body image was significantly correlated with poorer QOL during the first 2 years of follow-up regardless of study arm or treatment. Patients who crossed-over to a different treatment and patients with largest Cobb angles ≥ 40 degrees had significantly poorer body image, in particular self-body image, compared with those that did not. This study does not support findings from previous research indicating that wearing a brace has a negative impact on or is negatively impacted by body image or QOL. 2.

Red light emitting solid state hybrid quantum dot-near-UV GaN LED devices

International Nuclear Information System (INIS)

Song, Hongjoo; Lee, Seonghoon

2007-01-01

We produced core-shell (CdSe)ZnSe quantum dots by direct colloidal chemical synthesis and the surface-passivation method-an overcoating of the core CdSe with a larger-bandgap material ZnSe. The (CdSe)ZnSe quantum dots(QDs) play the role of a colour conversion centre. We call these quantum dots nanophosphors. We fabricated red light emitting hybrid devices of (CdSe)ZnSe QDs and a near-UV GaN LED by combining red light emitting (CdSe)ZnSe quantum dots (as a colour conversion centre) with a near-UV(NUV) GaN LED chip (as an excitation source). A few good red phosphors have been known for UV excitation wavelengths, and red phosphors for UV excitation have been sought for a long time. Here we tested the possibility of using (CdSe)ZnSe QDs as red nanophosphors for UV excitation. The fabricated red light emitting hybrid device of (CdSe)ZnSe and a NUV GaN LED chip showed a good luminance. We demonstrated that the (CdSe)ZnSe quantum dots were promising red nanophosphors for NUV excitation and that a red LED made of QDs and a NUV excitation source was a highly efficient hybrid device

Team care to cure adolescents with braces (avoiding low quality of life, pain and bad compliance): a case–control retrospective study. 2011 SOSORT Award winner

OpenAIRE

Tavernaro, Marta; Pellegrini, Anna; Tessadri, Fabrizio; Zaina, Fabio; Zonta, Andrea; Negrini, Stefano

2012-01-01

Abstract Background Bracing could be efficacious, given good compliance and quality of braces. Recently the SOSORT Brace Treatment Management Guidelines (SBTMG) have highlighted the perceived importance of the professional teams surrounding braced patients. Purpose To verify the impact of a complete rehabilitation team in the adolescent patient with bracing. Materials and methods Design. Initial cross-sectional study, followed by a retrospective case–control study. Population: Thirty-eight pa...

The effect of a dynamic PCL brace on patellofemoral compartment pressures in PCL-and PCL/PLC-deficient knees.

Science.gov (United States)

Welch, Tyler; Keller, Thomas; Maldonado, Ruben; Metzger, Melodie; Mohr, Karen; Kvitne, Ronald

2017-12-01

The natural history of posterior cruciate ligament (PCL) deficiency includes the development of arthrosis in the patellofemoral joint (PFJ). The purpose of this biomechanical study was to evaluate the hypothesis that dynamic bracing reduces PFJ pressures in PCL- and combined PCL/posterolateral corner (PLC)-deficient knees. Controlled Laboratory Study. Eight fresh frozen cadaveric knees with intact cruciate and collateral ligaments were included. PFJ pressures and force were measured using a pressure mapping system via a lateral arthrotomy at knee flexion angles of 30°, 60°, 90°, and 120° in intact, PCL-deficient, and PCL/PLC-deficient knees under a combined quadriceps/hamstrings load of 400 N/200 N. Testing was then repeated in PCL- and PCL/PLC-deficient knees after application of a dynamic PCL brace. Application of a dynamic PCL brace led to a reduction in peak PFJ pressures in PCL-deficient knees. In addition, the brace led to a significant reduction in peak pressures in PCL/PLC-deficient knees at 60°, 90°, and 120° of flexion. Application of the dynamic brace also led to a reduction in total PFJ force across all flexion angles for both PCL- and PCL/PLC-deficient knees. Dynamic bracing reduces PFJ pressures in PCL- and combined PCL/PLC-deficient knees, particularly at high degrees of knee flexion.

The cost-effectiveness of semi-rigid ankle brace to facilitate return to work following first-time acute ankle sprains.

Science.gov (United States)

Fatoye, Francis; Haigh, Carol

2016-05-01

To examine the cost-effectiveness of semi-rigid ankle brace to facilitate return to work following first-time acute ankle sprains. Economic evaluation based on cost-utility analysis. Ankle sprains are a source of morbidity and absenteeism from work, accounting for 15-20% of all sports injuries. Semi-rigid ankle brace and taping are functional treatment interventions used by Musculoskeletal Physiotherapists and Nurses to facilitate return to work following acute ankle sprains. A decision model analysis, based on cost-utility analysis from the perspective of National Health Service was used. The primary outcomes measure was incremental cost-effectiveness ratio, based on quality-adjusted life years. Costs and quality of life data were derived from published literature, while model clinical probabilities were sourced from Musculoskeletal Physiotherapists. The cost and quality adjusted life years gained using semi-rigid ankle brace was £184 and 0.72 respectively. However, the cost and quality adjusted life years gained following taping was £155 and 0.61 respectively. The incremental cost-effectiveness ratio for the semi-rigid brace was £263 per quality adjusted life year. Probabilistic sensitivity analysis showed that ankle brace provided the highest net-benefit, hence the preferred option. Taping is a cheaper intervention compared with ankle brace to facilitate return to work following first-time ankle sprains. However, the incremental cost-effectiveness ratio observed for ankle brace was less than the National Institute for Health and Care Excellence threshold and the intervention had a higher net-benefit, suggesting that it is a cost-effective intervention. Decision-makers may be willing to pay £263 for an additional gain in quality adjusted life year. The findings of this economic evaluation provide justification for the use of semi-rigid ankle brace by Musculoskeletal Physiotherapists and Nurses to facilitate return to work in individuals with first-time ankle

Boundary condition effect on response modification factor of X-braced steel frames

Directory of Open Access Journals (Sweden)

Walid A. Attia

2018-04-01

Full Text Available Design of the structures to resist seismic force depends on the theory of dissipation in elastic energy that already exists in response modification factor “R-factor”. The main problem in codes gives a constant value for R-factor, since change in boundary conditions of building change in behavior of braced steel frame structures and that effects on R-factor. This study is an attempt to assess overstrength, ductility and response modification factor of X-braced steel frame under change in boundary conditions, as change in the direction of strong axis of column and connection support type of column besides variation in storey and bays numbers to be 21 frames and each frame has 8 different boundary conditions as sum of 168 cases for analysis. These frames were analyzed by using nonlinear static “pushover” analysis. As results of this study change in support type and direction of strong axis of column give large change in value of R-factor; the minimum value was 4.37 and maximum value 10.97. Minimum value is close to code value that’s mean the code is more conservative in suggesting of R-factor and gives a large factor of safety. Change in the location of bracing gives change in value of R-factor for all boundary conditions. Change in direction of strong axis of columns and support type didn’t give change in value of fundamental period, all boundary conditions. Keywords: Response modification factor, Ductility reduction factor, Overstrength factor, Boundary conditions, Brace frame, Nonlinear static analysis “Pushover”

The importance of trunk perception during brace treatment in moderate juvenile idiopathic scoliosis: What is the impact on self-image?

Science.gov (United States)

Paolucci, Teresa; Piccinini, Giulia; Iosa, Marco; Piermattei, Cristina; De Angelis, Simona; Zangrando, Federico; Saraceni, Vincenzo Maria

2017-01-01

The perception of body image and the deformity of the trunk in patients with adolescent idiopathic scoliosis (AIS) are a silver lining that has yet to be discussed in the relevant literature during brace rehabilitation treatment. To determine whether and how the use of the brace changes perception of the trunk in patients with AIS by the drawing test. We observed 32 subjects with AIS from our Rehabilitation outpatient clinic and divided them into the brace treatment (BG-16 subjects) and the non-brace treatment (CG-16 subjects). Trunk perception and quality of life were evaluated using the Trunk Appearance Perception Scale and Scoliosis Research Society-22 questionnaire, and the perception of one's back was measured by the drawing test. Pain was lower in BG versus CG (p= 0.095). Satisfaction with the treatment was higher in BG than in CG (p= 0.002). Self-image did not differ significantly between the groups in terms of TAPS. Drawings of the most severe cases of scoliosis were made by the group without the brace. The use of the brace corrects the function of the trunk and has a positive influence on its perception.

[Conservative treatment of idiopathic scoliosis with effective braces: early response to trunk asymmetry may avoid curvature progress].

Science.gov (United States)

Matussek, J; Dingeldey, E; Wagner, F; Rezai, G; Nahr, K

2014-07-01

Vertical posture of the growing child requires minute central nervous control mechanisms in order to maintain symmetry of the torso in its various activities. Scoliosis describes a constant deviation in the frontal, transverse and sagittal planes from the dynamic symmetry of the trunk. Early intervention with effective bracing, physiotherapy and sports can reverse curve progression during growth spurts, once these are identified in screening. Modern braces have a derotating and reducing effect (mirror effect) on asymmetric body volumes, thus influencing the growing torso and restoring lasting symmetry. Recent data support the use of braces to reverse progressing scoliosis.

Complex dynamics in planar two-electron quantum dots

Energy Technology Data Exchange (ETDEWEB)

Schroeter, Sebastian Josef Arthur

2013-06-25

Quantum dots play an important role in a wide range of recent experimental and technological developments. In particular they are promising candidates for realisations of quantum bits and further applications in quantum information theory. The harmonically confined Hooke's atom model is experimentally verified and separates in centre-of-mass and relative coordinates. Findings that are contradictory to this separability call for an extension of the model, in particular changing the confinement potential. In order to study effects of an anharmonic confinement potential on spectral properties of planar two-electron quantum dots a sophisticated numerical approach is developed. Comparison between the Helium atom, Hooke's atom and an anharmonic potential model are undertaken in order to improve the description of quantum dots. Classical and quantum features of complexity and chaos are investigated and used to characterise the dynamics of the system to be mixed regular-chaotic. Influence of decoherence can be described by quantum fidelity, which measures the effect of a perturbation on the time evolution. The quantum fidelity of eigenstates of the system depends strongly on the properties of the perturbation. Several methods for solving the time-dependent Schrödinger equation are implemented and a high level of accuracy for long time evolutions is achieved. The concept of offset entanglement, the entanglement of harmonic models in the noninteracting limit, is introduced. This concept explains different questions raised in the literature for harmonic quantum dot models, recently. It shows that only in the groundstate the electrons are not entangled in the fermionic sense. The applicability, validity, and origin of Hund's first rule in general quantum dot models is further addressed. In fact Hund's first rule is only applicable, and in this case also valid, for one pair of singlet and triplet states in Hooke's atom. For more realistic models of two

Clinical Outcomes of a Pneumatic Unloader Brace for Kellgren-Lawrence Grades 3 to 4 Osteoarthritis: A Minimum 1-Year Follow-Up Study.

Science.gov (United States)

Chughtai, Morad; Bhave, Anil; Khan, Sabahat Z; Khlopas, Anton; Ali, Osman; Harwin, Steven F; Mont, Michael A

2016-11-01

The use of a pneumatic unloader brace has been shown in pilot studies to decrease pain and increase muscle strength in patients with knee osteoarthritis (OA). Therefore, we analyzed patients who had knee OA, and either received a pneumatic unloader brace and conventional treatment or conventional treatment alone. Specifically, we assessed: (1) use of pain relieving injections; (2) opioid consumption; and (3) the eventual need for total knee arthroplasty (TKA) in the above-mentioned cohort. We performed an analysis of a longitudinally maintained database of patients from a prospective, randomized, single center study. This study randomized patients who had Kellgren-Lawrence grades 3 to 4 to receive either a pneumatic unloader brace and conventional treatment or conventional treatment alone. The brace cohort comprised 11 patients with a mean age of 55 years (range, 37-70 years). The final matched cohort comprised 25 patients with a mean age of 63 years (range, 41-86 years). The minimum follow-up was 1 year. There was a lower proportion of patients who underwent an eventual TKA in the bracing cohort as compared with the nonbracing cohort (18 vs. 36%). The mean time to TKA was longer in the bracing cohort as compared with the nonbracing cohort (482 vs. 389 days). The proportion of patients who used opioids was similar in both groups (27 vs. 22%). There was a significantly lower number of patients who received injections in the bracing cohort as compared with the nonbracing cohort (46 vs. 83%, p  = 0.026). The bracing cohort had received a significantly lower number of injections and a lower rate of subsequent TKA as compared with the nonbracing cohort. The mean time to TKA was also longer among the bracing cohort. These results may demonstrate the potential of this brace to reduce the need for and prolonging the time to TKA. Performing larger prospective randomized studies, with built-in compliance monitors is warranted. This brace may be a valuable adjunct to the

Overweight is not predictive of bracing failure in adolescent idiopathic scoliosis: results from a retrospective cohort study.

Science.gov (United States)

Zaina, Fabio; Donzelli, Sabrina; Negrini, Stefano

2017-06-01

Overweight was found to be a negative predictor of brace effectiveness for adolescent idiopathic scoliosis (AIS), with a threefold higher risk of progression than in normal weight patients. The aim of this study is to investigate overweight, as a predictor of brace results in AIS patients. Design: retrospective cohort study. 351 AIS patients (306 females), mean age 12.9 ± 1.4, mean Cobb 35.6 ± 11.4°, mean ATR 11 ± 4.3°, BMI 19.7 ± 3, median Risser: 2. no previous treatment, full-time prescription of brace at first visit (18-23 h per day), scoliosis physiotherapeutic exercise according to the SEAS protocol associated. improved, progressed, and stable according to the 5° Cobb agreed threshold. a stepwise linear regression was used to look for the effect of BMI as a predictor of result. A Chi-square test and logistic regression were used for the overweight category (BMI ≥ 85th percentile). Control for possible confounders was applied. BMI is poorly correlated with final results. Confounders' adjustment did not change the correlation, and the predictive model explained about 10% of the result. Brace results were not statistically different in overweight and normal weight: 44 vs 52% improved, 52 vs 41% stable, and 3 vs 7% worsened, respectively. Brace results were similar in overweight and normal weight subjects. These findings subvert the previous results and disprove the role of overweight as a negative predictor. Treatment management, brace type and effectiveness may play a major role in reducing the risks of scoliosis progression.

The effect of Prophylactic knee bracing on selected performance ...

African Journals Online (AJOL)

The objective of this study was to determine if the wearing of a prophylactic knee brace by uninjured rugby players affected the following performance based parameters: speed, agility, strength, proprioception and economy of running. Thirty rugby players were subjected to a selected number of carefully monitored ...

Assessment of behavior factor of eccentrically braced frame with ...

African Journals Online (AJOL)

Assessment of behavior factor of eccentrically braced frame with vertical link in cyclic loading. ... Journal of Fundamental and Applied Sciences ... In order to understand the behavior of these structures using non-linear static and dynamic analysis of building's behavior factor, eccentric and exocentric systems were calculated ...

Brace treatment of lumber spondylolysis in growing age. Patient selection by RI scintigraphy and repair of spondylolysis

Energy Technology Data Exchange (ETDEWEB)

Abumi, Kuniyoshi; Hino, Hiroyuki; Sato, Shigeyoshi; Kaneda, Kiyoshi [Hokkaido Univ., Sapporo (Japan). School of Medicine

1996-07-01

From 1987 to 1994, brace treatment was prescribed to 29 patients with lumbar spondylolysis in growing age, ranging from nine to 18 years, in whom {sup 99m}Tc bone scintigraphy showed positive at the pars interarticularis. Single photon emission computed tomography was also conducted an recent cases. Spondylolysis was bilateral in 27 patients and unilateral in two. Polypropylene brace was applied for three to four months with restriction of sport activities. As a result, 46 out of 58 spondylolysis healed with a healing rate of 79%. Selection of patients using bone scintigraphy for brace treatment in lumbar spondylolysis in growing age would help to increase the union rate. (author)

Brace treatment of lumber spondylolysis in growing age. Patient selection by RI scintigraphy and repair of spondylolysis

International Nuclear Information System (INIS)

Abumi, Kuniyoshi; Hino, Hiroyuki; Sato, Shigeyoshi; Kaneda, Kiyoshi

1996-01-01

From 1987 to 1994, brace treatment was prescribed to 29 patients with lumbar spondylolysis in growing age, ranging from nine to 18 years, in whom 99m Tc bone scintigraphy showed positive at the pars interarticularis. Single photon emission computed tomography was also conducted an recent cases. Spondylolysis was bilateral in 27 patients and unilateral in two. Polypropylene brace was applied for three to four months with restriction of sport activities. As a result, 46 out of 58 spondylolysis healed with a healing rate of 79%. Selection of patients using bone scintigraphy for brace treatment in lumbar spondylolysis in growing age would help to increase the union rate. (author)

Conservative treatment of lateral epicondylitis: brace versus physical therapy or a combination of both: a randomized clinical trial

NARCIS (Netherlands)

Struijs, P. A. A.; Kerkhoffs, G. M. M. J.; Assendelft, W. J. J.; van Dijk, C. N.

2004-01-01

BACKGROUND: The authors evaluated the effectiveness of brace-only treatment, physical therapy, and the combination of these for patients with tennis elbow. METHODS: Patients were randomized over 3 groups: brace-only treatment, physical therapy, and the combination of these. Main outcome measures

Optimum Design of Braced Steel Space Frames including Soil-Structure Interaction via Teaching-Learning-Based Optimization and Harmony Search Algorithms

OpenAIRE

Ayse T. Daloglu; Musa Artar; Korhan Ozgan; Ali İ. Karakas

2018-01-01

Optimum design of braced steel space frames including soil-structure interaction is studied by using harmony search (HS) and teaching-learning-based optimization (TLBO) algorithms. A three-parameter elastic foundation model is used to incorporate the soil-structure interaction effect. A 10-storey braced steel space frame example taken from literature is investigated according to four different bracing types for the cases with/without soil-structure interaction. X, V, Z, and eccentric V-shaped...

Thermophysical properties and phase equilibria study of the binary systems {l_brace}N-hexylquinolinium bis(trifluoromethylsulfonyl)imide + aromatic hydrocarbons, or an alcohol{r_brace}

Energy Technology Data Exchange (ETDEWEB)

Domanska, Urszula, E-mail: ula@ch.pw.edu.p [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Thermodynamic Research Unit, School of Chemical Engineering, University of KwaZulu-Natal, Howard College Campus, King George V Avenue, Durban 4001 (South Africa); Zawadzki, Maciej [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Zwolinska, Magdalena [Department of Ergonomics, Laboratory of Thermal Loads, Central Institute for Labour Protection-National Research Institute, Czerniakowska 16, 00-701 Warsaw (Poland)

2011-05-15

Research highlights: We synthesized new ionic liquid, [HQuin][NTf{sub 2}] with low viscosity, and low density. We found high heat capacity, high enthalpy of melting and low melting temperature. HQuin][NTf{sub 2}] is proposed for possible use in the phase change materials (PCM). We examine phase equilibrium changes, SLE and LLE with hydrocarbons and alcohols. [HQuin][NTf{sub 2}] may be proposed as entrainer for the separation proceses. - Abstract: The new quinolinium ionic liquid has been synthesised as a continuation of our work with quinolinium-based ionic liquids (ILs). The work includes specific basic characterisation of synthesized compounds: N-hexylquinolinium bromide, [HQuin][Br] and N-hexylquinolinium bis{l_brace}(trifluoromethyl)sulfonyl{r_brace}imide [HQuin][NTf{sub 2}] by NMR spectra, elementary analysis and water content. The basic thermal properties of the pure [HQuin][NTf{sub 2}] i.e. melting and glass-transition temperatures, the enthalpy of fusion as well as heat capacity have been measured using a differential scanning microcalorimetry technique (DSC) and thermal analysis instrument (TA). Densities and viscosities were determined as a function of temperature. Phase equilibria for the binary systems: {l_brace}[HQuin][NTf{sub 2}]) + aromatic hydrocarbon (benzene, or toluene, or ethylbenzene, or n-propylbenzene), or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol){r_brace} have been determined at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from (270 to 320) K. For all the binary systems with benzene and alkylbenzenes, the eutectic diagrams were observed with immiscibility gap in the liquid phase beginning from (0.13 to 0.28) mole fraction of the IL with very high an upper critical solution temperature (UCST). For mixtures with alcohols, the complete miscibility was observed for 1-butanol and immiscibility with UCST in the liquid phase for the remaining alcohols. The typical

The Sforzesco brace can replace cast in the correction of adolescent idiopathic scoliosis: A controlled prospective cohort study

Directory of Open Access Journals (Sweden)

Zaina Fabio

2008-10-01

Full Text Available Abstract Background The conservative treatment of adolescent idiopathic scoliosis (AIS has traditionally been divided into two phases–correction and stabilisation–and casts, even if less used today, can be considered the best standard in the correction phase. Till the present, however, no comparison between cast and brace efficacy has been proposed. Methods This is a prospective cohort study with a retrospective control group. The aim was to verify if it is possible to obtain with a specifically developed rigid brace results comparable to a cast. We considered fifty AIS patients who had refused surgery, aged 14.1 ± 1.5 years, with 46.7 ± 7.8° Cobb scoliosis. Thirty-two consecutive patients (with no drop-outs were prospectively followed up with the Sforzesco brace (SBG, and compared against a retrospective group of eighteen patients treated with the Risser cast (RCG. The treatment time (the total correction phase was 19 ± 3 months. Out-of-brace x-rays were compared, as well as clinical results. Results Compliance and hours of treatment were higher in the RCG while all the other parameters were not different. We observed a reduction of 6° Cobb and an important aesthetic gain in both groups (P Conclusion In the corrective phase of AIS treatment it is possible with a specific rigid brace (Sforzesco – SPoRT concept to obtain scoliosis correction similar to cast. Due to the human and social costs of casting, and worst sagittal profile results, Sforzesco brace should be the preferred method wherever possible.

The B-Lynch uterine brace suture, and a bit of this and a bit of that...

Science.gov (United States)

Karoshi, Mahantesh

2010-03-01

The widespread application of the B-Lynch brace suture to control postpartum hemorrhage has sparked interest in a variety of adjunctive methods, used alone or in combination, to control uterine bleeding. Although the B-Lynch brace suture has been used with good results throughout the world, failures can and do occur in rare instances, especially when the suture is incorrectly placed for use for an inappropriate indication. Four reports of additional methods to control postpartum hemorrhage are published in this issue of IJGO. Three use the B-Lynch brace suture combined with other techniques. The need for additional techniques reminds the reader of the importance of proper suture application for proper indication. Potential reasons for failure of the B-Lynch suture are provided.

Supine Lateral Bending Radiographs Predict the Initial In-brace Correction of the Providence Brace in Patients With Adolescent Idiopathic Scoliosis

DEFF Research Database (Denmark)

Ohrt-Nissen, Søren; Hallager, Dennis Winge; Gehrchen, Poul Martin

2016-01-01

 ± 10°). Mean difference for thoracic curves was 0.2° (LOA ± 8°), for thoracolumbar/lumbar curves 0.9° (LOA ± 10°) and for double major curves 0.4° (LOA ± 16). CONCLUSION: SLBR provide a close estimation to the expected in-brace correction with a mean difference of less than one degree. SLRB could...

Automatic locking knee brace joint

Science.gov (United States)

Weddendorf, Bruce (Inventor)

1995-01-01

This invention is an apparatus for controlling the pivotal movement of a knee brace comprising a tang-and-clevis joint that has been uniquely modified. Both the tang and the clevis have a set of teeth that, when engaged, can lock the tang and the clevis together. In addition, the tang is biased away from the clevis. Consequently, when there is no axial force (i.e., body weight) on the tang, the tang is free to pivot within the clevis. However, when an axial force is exerted on the tang, the tang is pushed into the clevis, both sets of teeth engage, and the tang and the clevis lock together.

'SOSORT consensus paper on brace action: TLSO biomechanics of correction (investigating the rationale for force vector selection'

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Maruyama T

2006-07-01

Full Text Available Abstract Background The effectiveness of orthotic treatment continues to be controversial in international medical literature due to differences in the reported results and conclusions of various studies. Heterogeneity of the samples has been suggested as a reason for conflicting results. Besides the obvious theoretical differences between the brace concepts, the variability in the technical factors can also explain the contradictory results between same brace types. This paper will investigate the degree of variability among responses of scoliosis specialists from the Brace Study Ground of the International Society on Scoliosis Orthopedic and Rehabilitation Treatment SOSORT. Ultimately, this information could be a foundation for establishing a consensus and framework for future prospective controlled studies. Methods A preliminary questionnaire on the topic of 'brace action' relative to the theory of three-dimensional scoliosis correction and brace treatment was developed and circulated to specialists interested in the conservative treatment of adolescent idiopathic scoliosis. A particular case was presented (main thoracic curve with minor lumbar. Several key points emerged and were used to develop a second questionnaire which was discussed and full filed after the SOSORT consensus meeting (Milano, Italy, January 2005. Results Twenty-one questionnaires were completed. The Chêneau brace was the most frequently recommended. The importance of the three point system mechanism was stressed. Options about proper pad placement on the thoracic convexity were divided 50% for the pad reaching or involving the apical vertebra and 50% for the pad acting caudal to the apical vertebra. There was agreement about the direction of the vector force, 85% selecting a 'dorso lateral to ventro medial' direction but about the shape of the pad to produce such a force. Principles related to three-dimensional correction achieved high consensus (80%–85%, but suggested

Comfort and acceptability of various immobilization positions using a shoulder external rotation and abduction brace.

Science.gov (United States)

Hatta, Taku; Yamamoto, Nobuyuki; Sano, Hirotaka; Itoi, Eiji

2017-03-01

Immobilization with shoulder braces is used for conservative treatment of an initial shoulder dislocation. Various arm positions have been investigated to determine optimal position in terms of the anatomical reduction of the Bankart lesion. Recently, the effect of immobilization in shoulder abduction as well as in external rotation has been reported. However, there are few studies assessing subjects' acceptability of the brace in various arm positions. We hypothesized that a certain arm position regarding abduction or external rotation for immobilization would induce significant discomfort during activities of daily living. A dominant arm of 20 healthy participants was immobilized with a shoulder brace in 4 different positions; adduction and internal rotation (Add-IR), adduction and external rotation (Add-ER), 30° of abduction and 30° of external rotation (Abd-30ER), and 30° of abduction and 60° of external rotation (Abd-60ER). After completing immobilization for 24 h, subjects were asked to assess the discomfort of bracing for overall and individual activities, using a visual analogue scale. Data were compared among the four positions. For overall activities and several activities (eating, reading books, and removing and putting on pants), Abd-60ER was significantly more uncomfortable than adducted arm positions. Abd-30ER did not show any differences compared to the other arm positions. Immobilization in abduction and external rotation seems to be acceptable although the arm position in 30° of abduction and 60° of external rotation is less comfortable than the others. Our results might be useful in determining and developing the ideal shoulder brace which could keep patients' compliance and improve their outcomes. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Osmotic and activity coefficients of {l_brace}y Na{sub 2}SO{sub 4} + (1 - y) ZnSO{sub 4}{r_brace}(aq) at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Marjanovic, V. [High Technical School, Trg Svetog Save 34, 31 000 Uzice (Serbia and Montenegro); Ninkovic, R. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia and Montenegro); Miladinovic, J. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia and Montenegro)]. E-mail: duma@elab.tmf.bg.ac.yu; Todorovic, M. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia and Montenegro); Pavicevic, V. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia and Montenegro)

2005-02-01

The osmotic coefficients of the mixed electrolyte solution {l_brace}y Na{sub 2}SO{sub 4} + (1 - y) ZnSO{sub 4}{r_brace}(aq) have been measured by the isopiestic method, at T = 298.5 K. The experimental results were treated by Scatchard's, Pitzer-Kim's and Clegg-Pitzer-Brimblecombe's methods for mixed-electrolyte solutions. By these methods, the activity coefficients for Na{sub 2}SO{sub 4} and ZnSO{sub 4} were calculated and compared. The Scatchard interaction parameters are used for calculation of the excess Gibbs free energy as a function of ionic strength and ionic-strength fraction of Na{sub 2}SO{sub 4}. Also, the Zdanovskii's rule of linearity is tested.

Outcome of humeral shaft fractures treated by functional cast brace

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Jitendra Nath Pal

2015-01-01

Conclusion: Modified functional cast brace is one of the options in treatment for humeral shaft fractures as it can be applied on the 1 st day of the presentation in most of the situations. Simple objective scoring system was useful particularly in uneducated patients.

Bracing Regular Polygons as We Race into the Future

Science.gov (United States)

Frederickson, Greg N.

2012-01-01

How many rods does it take to brace a square in the plane? Once Martin Gardner's network of readers got their hands on it, it turned out to be fewer than Raphael Robinson, who originally posed the problem, thought. And who could have predicted the stunning solutions found subsequently for various generalizations of the problem?

Design method of redundancy of brace-anchor sharing supporting based on cooperative deformation

Science.gov (United States)

Liu, Jun-yan; Li, Bing; Liu, Yan; Cai, Shan-bing

2017-11-01

Because of the complicated environment requirement, the support form of foundation pit is diversified, and the brace-anchor sharing support is widely used. However, the research on the force deformation characteristics and the related aspects of the cooperative response of the brace-anchor sharing support is insufficient. The application of redundancy theory in structural engineering has been more mature, but there is little theoretical research on redundancy theory in underground engineering. Based on the idea of collaborative deformation, the paper calculates the ratio of the redundancy degree of the cooperative deformation by using the local reinforcement design method and the structural component redundancy parameter calculation formula based on Frangopol. Combined with the engineering case, through the calculation of the ratio of cooperative deformation redundancy in the joint of brace-anchor sharing support. This paper explores the optimal anchor distribution form under the condition of cooperative deformation, and through the analysis and research of displacement field and stress field, the results of the collaborative deformation are validated by comparing the field monitoring data. It provides theoretical basis for the design of this kind of foundation pit in the future.

Team care to cure adolescents with braces (avoiding low quality of life, pain and bad compliance: a case–control retrospective study. 2011 SOSORT Award winner

Directory of Open Access Journals (Sweden)

Tavernaro Marta

2012-09-01

Full Text Available Abstract Background Bracing could be efficacious, given good compliance and quality of braces. Recently the SOSORT Brace Treatment Management Guidelines (SBTMG have highlighted the perceived importance of the professional teams surrounding braced patients. Purpose To verify the impact of a complete rehabilitation team in the adolescent patient with bracing. Materials and methods Design. Initial cross-sectional study, followed by a retrospective case–control study. Population: Thirty-eight patients (15.8 ± 1.6 years; 26 females; 10 hyperkyphosis, 28 scoliosis of 29.2 ± 7.9° Cobb extracted from a single orthotist database (between January 1, 2008 and September 1, 2009 and treated by the same physician; brace wearing at least 15 hours/day for a minimum of 6 months; age 10 or more. Treatment: Braces: Sforzesco, Sibilla, Lapadula or Maguelone. Exercises: SEAS. Methods: Two questionnaires filled in blindly by patients: SRS-22 and one especially developed and validated with 25 questions on adherence to treatment. Groups (main risk factor: TEAM (private institute: satisfied 44/44 SOSORT criteria; grade of teamwork, “excellent” included 13 patients and NOT 25 (National Health Service Rehabilitation Department: 35/44 SOSORT criteria respected; grade, “insufficient”. Results TEAM was more compliant to bracing than NOT (97 ± 6% vs. 80 ± 24% and performed nearly double the exercises (38 ± 12 vs. 20 ± 13 minutes/session. The self-reduction of bracing was significant in NOT (from 16.8 ± 3.7 to 14.8 ± 4.9 hours/day, , P Conclusions Provided the limits of this first study on the topic, the SBTMG seems to be important for brace treatment, influencing pain, QoL and compliance (and so, presumably, final results. Future studies on the topic are advisable.

Hysteretic Behavior of Tubular Steel Braces Having Carbon Fiber Reinforced Polymer Reinforcement Around End Net Sections

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Cem Haydaroğlu

2015-12-01

Full Text Available This study presents an experimental investigation into the seismic retrofit of tubular steel braces using carbon fiber reinforced polymer (CFRP members. CFRP retrofitting of net sections for compact tubes are proposed for delaying potential local net section failure. A total of almost full-scale three (TB-1, TB-2, and TB-3 compact steel tubular specimens were designed per AISC specifications, constructed, and cyclically tested to fracture. Retrofitted braces, when compared to the reference specimen, developed fuller hysteretic curves. Increase in cumulative hysteretic energy dissipation and the elongation in fracture life in the specimen retrofitted with CFRP plates and CFRP sheet wraps at net sections are observed during testing. This resulted in a maximum of 82.5% more dissipated energy for compact tube specimens. Also, this retrofit provided a longer experimental fracture life (maximum 59% more. Due to fracture initiation during the last cycles, significant reductions in strength and stiffness have been obtained. No significant change (maximum 10% in the brace stiffness was observed, which could be desirable in seismic retrofit applications. Pushover analysis per FEMA 356 for the bare specimen shows that FEMA does not represent actual brace behavior in the compression side although pushover and experimental results are in good agreement in the tension side.

Treatment of adolescent lumber spondylolysis with modified Boston brace. Selection of the patients with bone scintigraphy and repair of the part defects

International Nuclear Information System (INIS)

Hino, Hiroyuki; Abumi, Kuniyoshi; Kaneda, Kiyoshi; Sato, Eishu

1996-01-01

Results of brace treatment of 29 spondylolysis patients were reported. Patients were those who were diagnosed by scout roentgenography and accumulated 99m Tc at spondylolytic site by bone scintigraphy or by single photon emission computed tomography (SPECT) which being found more convenient to see the accumulation than the scintigraphy. Coaptation after brace treatment was observed by flat and tomographic roentgenography. Under limited sports activity, the hard brace was used for about 4 months and then soft one, for 2 months. Coaptation and repair were observed for 46 (79%) of 58 part defects in the 29 patients. Since lumber spine spondylolysis is mostly caused by fatigue fracture and bone metabolism is activated at the lesional site, 99m Tc accumulation can be seen at the spondylolytic site by bone scintigraphy with high frequency. Therefore, the rate of repair can be increased when brace treatment was applied for patients with positive bone scintigraphy findings. The scintigraphy was thus useful far selecting patients suitable for brace treatment. (K.H.)

Experimental Investigation on the Behavior of Bracing Damper Systems by Utilizing Metallic Yielding and Recentering Material Devices

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Jong Wan Hu

2018-01-01

Full Text Available With the aim of effectively reducing the structural damage caused by earthquake events, bracing systems equipped with retrofitting damper devices, which take advantage of the energy dissipation and impact absorption, have been widely used in practical construction sites. These bracing dampers, however, have been recognized as expendable supplies for easily replacing the damaged ones after a strong earthquake because they are commonly designed to undergo concentrated force and deformation for the purpose of protecting the main structural members such as the columns and beams. In this paper, the use of new superelastic shape memory alloy (SMA dampers that can partially recover their original configuration is proposed to decrease the repair cost. In addition, the conventional steel dampers used for improving the energy dissipation arising due to metallic yielding are additionally integrated into the bracing member. The behaviors of such bracing systems with the damper devices were reproduced in experimental tests with the cyclic loading history, and then their strength capacity and recentering capability were estimated based on the experiment results. Finally, additional experimental tests were performed by imposing cyclic loading histories with different loading speeds on the superelastic SMA and steel plate damper specimens.

Synthesis, structures and properties of a series of manganese coordination complexes constructed from dicarboxylic fluorene derivatives

Energy Technology Data Exchange (ETDEWEB)

Li Xing, E-mail: lixing@nbu.edu.cn [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang, 315211 (China); Zhao Xiuhua; Bing Yue; Zha Meiqin; Xie Hongzhen; Guo Zhiyong [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang, 315211 (China)

2013-01-15

Assembly reactions of 9,9-diethylfluorene-2,7-dicarboxylic acid (H{sub 2}DFDC) and Mn(CH{sub 3}COO){sub 2}{center_dot}4H{sub 2}O or MnCl{sub 2}{center_dot}4H{sub 2}O by tuning of various secondary ligands such as 2,2 Prime -bipyridine (2,2 Prime -bpy), 4,4 Prime -bipyridine (4,4 Prime -bpy) or 1,3-bis(4-pyridyl)propane) (bpp), gave rise to four complexes {l_brace} [Mn{sub 2}(DFDC){sub 2}(DMF){sub 2}]{center_dot}H{sub 2}O{r_brace} {sub n} (1), [Mn(DFDC)(2,2 Prime -bpy)]{sub n} (2), {l_brace} [Mn{sub 2}(DFDC){sub 2}(4,4 Prime -bpy){sub 2}]{center_dot}2CH{sub 3}OH{r_brace} {sub n} (3), and {l_brace} [Mn{sub 4}(DFDC){sub 4}(bpp){sub 2}(CH{sub 3}OH){sub 3} (H{sub 2}O){sub 3}]{center_dot}3(CH{sub 3}OH){center_dot}3(H{sub 2}O){r_brace} {sub n} (4). Single crystal X-ray diffraction analysis reveal that complex 1 is three dimensional structure with rhombic channels filled by guest water molecules; 2 presents a close-packed structure with high thermal stability; 3 exhibits a three dimensional framework with micro-porous channels filled by guest methanol molecules and 4 is a two-dimensional structure. The photoluminescent properties of 1-4 have been studied, respectively, showing that the Mn(II) ions, accessorial organic ligands or crystal structures exert important influences on the photoluminescence emissions of H{sub 2}DFDC ligands. Thermogravimetric analysis show that the complexes have remarkably high thermal stability. Magnetic susceptibility measurements have been finished and discussed for the complexes. - Graphical abstract: Assembly of 9,9-diethylfluorene-2,7-dicarboxylic acid and Mn(II) salts by tuning of various accessorial ligands resulted in four manganese complexes with different topological frameworks. Highlights: Black-Right-Pointing-Pointer Four manganese complexes based on 9,9-diethylfluorene-2,7-dicarboxylic acid were obtained. Black-Right-Pointing-Pointer The complexes were structurally characterized by single-crystal X-ray diffraction. Black

Combined versus individual effects of a valgus knee brace and lateral wedge foot orthotic during stair use in patients with knee osteoarthritis.

Science.gov (United States)

Moyer, Rebecca; Birmingham, Trevor; Dombroski, Colin; Walsh, Robert; Giffin, J Robert

2017-05-01

The aim of this study was to investigate the combined and individual biomechanical effects of a valgus knee brace and a lateral wedge foot orthotic during stair ascent and descent in patients with knee osteoarthritis (OA). Thirty-five patients with varus alignment and medial knee OA were prescribed a custom valgus knee brace and lateral wedge foot orthotic. Knee angles and moments in the frontal and sagittal planes were determined from 3D gait analysis completed under four randomized conditions: (1) control (no knee brace or foot orthotic), (2) knee brace, (3) foot orthotic, and (4) combined knee brace and foot orthotic. Additional measures included the vertical ground reaction force, trunk lean, toe out and gait speed. During the combined use of a knee brace and foot orthotic, significant decreases in the knee adduction angle (2.17, 95%CI: 0.50-3.84, p=0.013) and 2nd peak EKAM (0.35, 95%CI: 0.17-0.52, pstair descent; and significant increases in the EKFM were observed during stair ascent (0.54, 95%CI: 0.30-0.78, pstair descent compared to ascent, except for toe out. Findings suggest greater effects on gait when both knee brace and foot orthotic are used together, resulting in a more normal gait pattern. However, whether or not a true change in knee joint load can be inferred when using these orthoses remains unclear. Further research is required to determine the clinical importance of the observed changes. Copyright © 2017. Published by Elsevier B.V.

InAs/GaAs quantum dots for THz generation

International Nuclear Information System (INIS)

Daghestani, N.S.; Cataluna, M.A.; Berry, G.; Rose, M.J.; Ross, G.

2012-01-01

We report pulsed terahertz generation from InAs/GaAs quantum-dot based photoconductive devices. For 800 nm optical excitation, the dots act as recombination centres for carriers generated in the GaAs layers. Using photoreflective pump-probe measurements we demonstrate that the photogenerated carrier lifetime decreases when a lateral bias is applied. This can be attributed to an increase in the capture area of the dots when under bias. Two types of antenna metallization were investigated; non-Ohmic, and quasi-Ohmic contacts. Non-Ohmic antennae displayed resilience to Joule heating when operated at a field strength of 46 MV/m. The breakdown field of the devices was 48 MV/m, which is comparable to the breakdown field of bulk GaAs (∝50 MV/m). The maximum estimated infrared-to-THz conversion efficiency is ∝1x10 -5 . (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Optimum Design of Braced Steel Space Frames including Soil-Structure Interaction via Teaching-Learning-Based Optimization and Harmony Search Algorithms

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Ayse T. Daloglu

2018-01-01

Full Text Available Optimum design of braced steel space frames including soil-structure interaction is studied by using harmony search (HS and teaching-learning-based optimization (TLBO algorithms. A three-parameter elastic foundation model is used to incorporate the soil-structure interaction effect. A 10-storey braced steel space frame example taken from literature is investigated according to four different bracing types for the cases with/without soil-structure interaction. X, V, Z, and eccentric V-shaped bracing types are considered in the study. Optimum solutions of examples are carried out by a computer program coded in MATLAB interacting with SAP2000-OAPI for two-way data exchange. The stress constraints according to AISC-ASD (American Institute of Steel Construction-Allowable Stress Design, maximum lateral displacement constraints, interstorey drift constraints, and beam-to-column connection constraints are taken into consideration in the optimum design process. The parameters of the foundation model are calculated depending on soil surface displacements by using an iterative approach. The results obtained in the study show that bracing types and soil-structure interaction play very important roles in the optimum design of steel space frames. Finally, the techniques used in the optimum design seem to be quite suitable for practical applications.

The influence of elastic orthotic belt on sagittal profile in adolescent idiopathic thoracic scoliosis: a comparative radiographic study with Milwaukee brace

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Qian Bangping

2010-09-01

Full Text Available Abstract Background The effectiveness of bracing on preventing curve progression in coronal plane for mild and moderate adolescent idiopathic scoliosis (AIS patients has been confirmed by previous radiographic researches. However, a hypokyphotic effect on the sagittal plane has been reported by a few studies. A relatively increasing number of AIS patients were noticed to wear a new kind of elastic orthotic belt for the treatments of scoliosis without doctors' instructions. We postulate the correcting mechanism of this new appliance may cause flattening of the spine. To our knowledge, no study has investigated the effects of this new orthosis on the sagittal profile of AIS patients. The aim of this study was to evaluate and compare the effects of elastic orthotic belt and Milwaukee brace on the sagittal alignment in AIS patients. Methods Twenty-eight female AIS patients with mild or moderate thoracic curves were included in this study. Standing full-length lateral radiographs were obtained in three conditions: natural standing posture without any treatment, with elastic orthotic belt and with Milwaukee brace. Thoracic kyphosis (TK, lumber lordosis (LL and pelvic incidence (PI were measured and compared between the above three conditions. Results Both elastic orthotic belt and Milwaukee brace can lead to significant decrease of TK, however, the decrease of TK after wearing elastic orthotic belt is significantly larger than that after wearing Milwaukee brace. Compared with no treatment, LL was found to be significantly smaller after wearing Milwaukee brace, however, such significant decrease was not noted after wearing elastic orthotic belt. No significant changes were observed for the PI between 3 conditions. Conclusions The elastic orthotic belt could lead to more severe thoracic hypokyphosis when compared with Milwaukee brace. This belt may not be a suitable conservative method for the treatment of mild and moderate AIS patients.

Long-term results after Boston brace treatment in adolescent idiopathic scoliosis

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Steen Harald

2009-08-01

Full Text Available Abstract Background Few studies have evaluated long-term outcome after bracing using validated health related quality of life outcome measures. The aim of the present study was to evaluate the long-term outcome in adolescent idiopathic scoliosis (AIS 12 years or more after treatment with the Boston brace. Methods 109 (80% of 135 patients (7 men with AIS treated with the Boston brace at a mean of 19.2 (range 12–28 years previously responded to long-term follow-up examination. All patients (n = 109 answered a standardised questionnaire including demographics, work status, treatment, Global Back Disability Question, Oswestry Disability Index (ODI (100-worst possible, General Function Score (GFS (100 – worst possible, EuroQol (EQ-5D (1 – best possible, EQ-VAS (100 – best possible and Scoliosis Research Society -22 (SRS – 22 (5 – best possible. Clinical and radiological examination was obtained in 86 patients. Results The magnitude of the primary prebrace major curve was in average 33.4° (range 20 – 52. At weaning and at the last follow-up the corresponding values were 28.3° (9–56 and 34.2° (8 – 87, respectively. The mean age at follow-up was 35 (27 – 46 years. Work status was: full time (80%, on sick-leave (3%, on rehabilitation (4%, disability pension (4%, homemaker (7%, students (2%, 7% had changed their job because of back pain. 88% had had delivered a baby, 55% of them had pain in pregnancy. Global back status was excellent or good in 81%. The mean (standard deviation ODI was 6.4 (9.8, GFS 5.4 (10.5, EQ-5D 0.84 (0.2, SRS-22: pain 4.2 (0.8, mental health 4.2 (0.7, self-image 3.9 (0.7, function 4.1 (0.6, satisfaction with treatment 3.7 (1.0. 28% had taken physiotherapy for back pain the last year and 12% had visited a doctor. Conclusion Long-term results were satisfactory in most patients with AIS treated with the Boston brace.

Treatment of adolescent lumber spondylolysis with modified Boston brace. Selection of the patients with bone scintigraphy and repair of the part defects

Energy Technology Data Exchange (ETDEWEB)

Hino, Hiroyuki; Abumi, Kuniyoshi; Kaneda, Kiyoshi; Sato, Eishu [Hokkaido Univ., Sapporo (Japan). School of Medicine

1996-06-01

Results of brace treatment of 29 spondylolysis patients were reported. Patients were those who were diagnosed by scout roentgenography and accumulated {sup 99m}Tc at spondylolytic site by bone scintigraphy or by single photon emission computed tomography (SPECT) which being found more convenient to see the accumulation than the scintigraphy. Coaptation after brace treatment was observed by flat and tomographic roentgenography. Under limited sports activity, the hard brace was used for about 4 months and then soft one, for 2 months. Coaptation and repair were observed for 46 (79%) of 58 part defects in the 29 patients. Since lumber spine spondylolysis is mostly caused by fatigue fracture and bone metabolism is activated at the lesional site, {sup 99m}Tc accumulation can be seen at the spondylolytic site by bone scintigraphy with high frequency. Therefore, the rate of repair can be increased when brace treatment was applied for patients with positive bone scintigraphy findings. The scintigraphy was thus useful far selecting patients suitable for brace treatment. (K.H.)

Effect of Prophylactic Ankle-Brace Use During a High School Competitive Basketball Season on Dynamic Postural Control.

Science.gov (United States)

Crockett, Nathan J; Sandrey, Michelle A

2015-08-01

Few studies have evaluated the long-term effects of prophylactic ankle-brace use during a sport season. To determine the effects of prophylactic ankle-brace use during a high school basketball season on dynamic postural control and functional tests. Prospective repeated-measures design. High school athletic facility. 21 healthy high school basketball athletes (13 girls, 8 boys). The order of testing was randomized using the Star Excursion Balance Test (SEBT) for posteromedial (PM), medial (M), and anteromedial (AM) directions and 3 functional tests (FT) consisting of the single-leg crossover hop, single-leg vertical jump, and the single-leg 6-m hop for time at pre-, mid-, and postseason. After pretesting, the ankle brace was worn on both limbs during the entire 16-wk competitive basketball season. SEBT for PM, M, and AM and 3 single-leg FTs. Dynamic postural control using the SEBT and the 3 FTs improved over time, notably from pretest to posttest. The left limb was different from the right limb during the single-leg vertical jump. Effect sizes were large for pretest to posttest for the 3 SEBT directions and 2 of the 3 FTs. The 16-wk basketball prophylactic ankle-brace intervention significantly improved dynamic postural control and single-limb FTs over time.

Polish adaptation of Bad Sobernheim Stress Questionnaire-Brace and Bad Sobernheim Stress Questionnaire-Deformity.

Science.gov (United States)

Misterska, Ewa; Głowacki, Maciej; Harasymczuk, Jerzy

2009-12-01

Bad Sobernheim Stress Questionnaire-Brace and Bad Sobernheim Stress Questionnaire-Deformity are relatively new tools aimed at facilitating the evaluation of long-term results of therapy in persons with idiopathic scoliosis undergoing conservative treatment. To use these tools properly in Poland, they must be translated into Polish and adapted to the Polish cultural settings. The process of cultural adaptation of the questionnaires was compliant with the guidelines of International Quality of Life Assessment (IQOLA) Project. In the first stage, two independent translators converted the originals into Polish. Stage two, consisted of a comparison of the originals and two translated versions. During that stage, the team of two translators and authors of the project identified differences in those translations and created a combination of the two. In the third stage, two independent translators, who were native speakers of German, translated the adjusted version of the Polish translation into the language of the original document. At the last stage, a commission composed of: specialists in orthopedics, translators, a statistician and a psychologist reviewed all translations and drafted a pre-final version of the questionnaires. Thirty-five adolescent girls with idiopathic scoliosis who were treated with Cheneau brace were subjected to the questionnaire assessment. All patients were treated in an out-patient setting by a specialist in orthopedics at the Chair and Clinic of Orthopedics and Traumatology. Median age of patients was 14.8 SD 1.5, median value of the Cobb's angle was 27.8 degrees SD 7.4. 48.6% of patients had thoracic scoliosis, 31.4% had thoracolumbar scoliosis, and 20% patients had lumbar scoliosis. Median results obtained by means of the Polish version of BSSQ-Brace and BSSQ-Deformity questionnaires were 17.9 SD 5.0 and 11.3 SD 4.7, respectively. Internal consistency of BSSQ-Brace and BSSQ-Deformity was at the level of 0.80 and 0.87, whereas the value of

Healing of the Acutely Injured Anterior Cruciate Ligament: Functional Treatment with the ACL-Jack, a Dynamic Posterior Drawer Brace

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Matthias Jacobi

2016-01-01

Full Text Available Background. The injured anterior cruciate ligament (ACL has a limited healing capacity leading to persisting instability. Hypothesis/Purpose. To study if the application of a brace, producing a dynamic posterior drawer force, after acute ACL injury reduces initial instability. Study Design. Cohort study. Methods. Patients treated with the ACL-Jack brace were compared to controls treated with primary ACL reconstruction und controls treated nonsurgically with functional rehabilitation. Measurements included anterior laxity (Rolimeter, clinical scores (Lysholm, Tegner, and IKDC, and MRI evaluation. Patients were followed up to 24 months. Results. Patients treated with the ACL-Jack brace showed a significant improvement of anterior knee laxity comparable to patients treated with ACL reconstruction, whereas laxity persisted after nonsurgical functional rehabilitation. The failure risk (secondary reconstruction necessary of the ACL-Jack group was however 21% (18 of 86 within 24 months. Clinical scores were similar in all treatment groups. Conclusion. Treatment of acute ACL tears with the ACL-Jack brace leads to improved anterior knee laxity compared to nonsurgical treatment with functional rehabilitation.

Comparison of the effect of semi-rigid ankle bracing on performance ...

African Journals Online (AJOL)

Objective. To determine the comparative proprioceptive performance of injured v. non-injured adolescent female hockey players wearing an ankle brace. Methods. Data were collected from 100 high school players who belonged to the Highway Secondary School Hockey League, KwaZulu- Natal, via voluntary parental ...

GRUNCLE, 1. Collision Source Calculation for Program DOT. DOT-3.5, 2-D Neutron Transport, Gamma Transport Program DOT with New Space-Scaling

International Nuclear Information System (INIS)

1996-01-01

mesh. Anisotropic scattering is treated using a Legendre expansion of arbitrary order. Convergence can be accelerated by several optional schemes, including a pointwise rescaling technique. DOT-3.5/E: Differs from DOT-3.5 in that exponential supplementary equations, as well as the usual diamond and weighted schemes, may be used to find the mesh-centre flux from the fluxes at the faces of the mesh. The model: 1. always gives positive solutions and does not require any fix-up techniques provided that the source is non-negative; 2. improves convergence rate in most neutron deep-penetration problems and, for any practical spatial discretization, always requires CPU times not only smaller than those required by DOT-3 mixed (linear + step fix-up) model, but also shorter (generally 10-20%) than the times required by DOT-3.5 weighted difference model; 3. increasing spatial mesh size supplies solutions which are always reasonable overestimates of the exact solution and its numerical behaviour is more stable and coherent than the mixed mode. Experience up to now from several deep penetration problems in (r,z) and (x,y) geometry shows that, while for neutrons the exponential model almost always works very well, for gamma rays its behaviour may be critical and in some cases there is lack of convergence. C - Restrictions on the complexity of the problem: The total storage requirement is determined by a formula given in the input description. No other restrictions to problem size are applicable

Curve progression after long-term brace treatment in adolescent idiopathic scoliosis: comparative results between over and under 30 Cobb degrees - SOSORT 2017 award winner

Directory of Open Access Journals (Sweden)

Angelo G. Aulisa

2017-10-01

Full Text Available Abstract Background The factors influencing curve behavior following bracing are incompletely understood and there is no agreement if scoliotic curves stop progressing with skeletal maturity. The aim of this study was to evaluate the loss of the scoliotic curve correction in patients treated with bracing during adolescence and to compare patient outcomes of under and over 30 Cobb degrees, 10 years after brace removal. Methods We reviewed 93 (87 female of 200 and nine patients with adolescent idiopathic scoliosis (AIS who were treated with the Lyon or PASB brace at a mean of 15 years (range 10–35. All patients answered a simple questionnaire (including work status, pregnancy, and pain and underwent clinical and radiological examination. The population was divided into two groups based on Cobb degrees ( 30°. Statistical analysis was performed to test the efficacy of our hypothesis. Results The patients underwent a long-term follow-up at a mean age of 184.1 months (±72.60 after brace removal. The pre-brace scoliotic mean curve was 32.28° (± 9.4°; after treatment, the mean was 19.35° and increased to a minimum of 22.12° in the 10 years following brace removal. However, there was no significant difference in the mean Cobb angle between the end of weaning and long term follow-up period (p = 0.105. The curve angle of patients who were treated with a brace from the beginning was reduced by 13° during the treatment, but the curve size lost 3° at the follow-up period. The groups over 30° showed a pre-brace scoliotic mean curve of 41.15°; at the end of weaning, the mean curve angle was 25.85° and increased to a mean of 29.73° at follow-up; instead, the groups measuring ≤ 30° showed a pre-brace scoliotic mean curve of 25.58°; at the end of weaning, it was reduced to a mean of 14.24° and it increased to 16.38° at follow-up. There was no significant difference in the mean progression of curve magnitude between the ≤ 30° and

Team care to cure adolescents with braces (avoiding low quality of life, pain and bad compliance): a case-control retrospective study. 2011 SOSORT Award winner.

Science.gov (United States)

Tavernaro, Marta; Pellegrini, Anna; Tessadri, Fabrizio; Zaina, Fabio; Zonta, Andrea; Negrini, Stefano

2012-09-20

Bracing could be efficacious, given good compliance and quality of braces. Recently the SOSORT Brace TREATMENT Management Guidelines (SBTMG) have highlighted the perceived importance of the professional teams surrounding braced patients. To verify the impact of a complete rehabilitation team in the adolescent patient with bracing. Design. Initial cross-sectional study, followed by a retrospective case-control study. Thirty-eight patients (15.8 ± 1.6 years; 26 females; 10 hyperkyphosis, 28 scoliosis of 29.2 ± 7.9° Cobb) extracted from a single orthotist database (between January 1, 2008 and September 1, 2009) and treated by the same physician; brace wearing at least 15 hours/day for a minimum of 6 months; age 10 or more. Braces: Sforzesco, Sibilla, Lapadula or Maguelone. Exercises: SEAS. Two questionnaires filled in blindly by patients: SRS-22 and one especially developed and validated with 25 questions on adherence to treatment. Groups (main risk factor): TEAM (private institute: satisfied 44/44 SOSORT criteria; grade of teamwork, "excellent") included 13 patients and NOT 25 (National Health Service Rehabilitation Department: 35/44 SOSORT criteria respected; grade, "insufficient"). TEAM was more compliant to bracing than NOT (97 ± 6% vs. 80 ± 24%) and performed nearly double the exercises (38 ± 12 vs. 20 ± 13 minutes/session). The self-reduction of bracing was significant in NOT (from 16.8 ± 3.7 to 14.8 ± 4.9 hours/day, , Pversus 7% of TEAM (P < 0.05). The populations did not differ at the baseline studied outcomes. The absence of a good team surrounding the patient increases by five times the risk of reduced compliance to bracing (odds ratio OR 5.5 - 95% confidence interval 95CI 3.6-7.4), along with more than 15 times that of QoL problems (OR 15.7 - 95CI 13.6-17.9) and pain (OR 16.8 - 95CI 14.5-19.1). Provided the limits of this first study on the topic, the SBTMG seems to be important for brace treatment

Quantum Dots

Science.gov (United States)

Tartakovskii, Alexander

2012-07-01

Part I. Nanostructure Design and Structural Properties of Epitaxially Grown Quantum Dots and Nanowires: 1. Growth of III/V semiconductor quantum dots C. Schneider, S. Hofling and A. Forchel; 2. Single semiconductor quantum dots in nanowires: growth, optics, and devices M. E. Reimer, N. Akopian, M. Barkelid, G. Bulgarini, R. Heeres, M. Hocevar, B. J. Witek, E. Bakkers and V. Zwiller; 3. Atomic scale analysis of self-assembled quantum dots by cross-sectional scanning tunneling microscopy and atom probe tomography J. G. Keizer and P. M. Koenraad; Part II. Manipulation of Individual Quantum States in Quantum Dots Using Optical Techniques: 4. Studies of the hole spin in self-assembled quantum dots using optical techniques B. D. Gerardot and R. J. Warburton; 5. Resonance fluorescence from a single quantum dot A. N. Vamivakas, C. Matthiesen, Y. Zhao, C.-Y. Lu and M. Atature; 6. Coherent control of quantum dot excitons using ultra-fast optical techniques A. J. Ramsay and A. M. Fox; 7. Optical probing of holes in quantum dot molecules: structure, symmetry, and spin M. F. Doty and J. I. Climente; Part III. Optical Properties of Quantum Dots in Photonic Cavities and Plasmon-Coupled Dots: 8. Deterministic light-matter coupling using single quantum dots P. Senellart; 9. Quantum dots in photonic crystal cavities A. Faraon, D. Englund, I. Fushman, A. Majumdar and J. Vukovic; 10. Photon statistics in quantum dot micropillar emission M. Asmann and M. Bayer; 11. Nanoplasmonics with colloidal quantum dots V. Temnov and U. Woggon; Part IV. Quantum Dot Nano-Laboratory: Magnetic Ions and Nuclear Spins in a Dot: 12. Dynamics and optical control of an individual Mn spin in a quantum dot L. Besombes, C. Le Gall, H. Boukari and H. Mariette; 13. Optical spectroscopy of InAs/GaAs quantum dots doped with a single Mn atom O. Krebs and A. Lemaitre; 14. Nuclear spin effects in quantum dot optics B. Urbaszek, B. Eble, T. Amand and X. Marie; Part V. Electron Transport in Quantum Dots Fabricated by

Effect of K?nes?otap?ng and Knee Brace on Funct?onal Performance in Recreat?onal Athletes

OpenAIRE

Ulusoy, Burak; ?ldiz, B?lent; Tunay, Volga Bayrak??

2014-01-01

Objectives: Kinesiotaping is a popular taping method that is used for both therapeutic and performance enchancement purposes. Knee braces are widely used for prevention in sport injuries but their performance effectiveness is still controversial. The aim of this study was to determine whether kinesiotape or brace was more effective on functional performance. Methods: A total twenty male recreational football players (Mean?Standart Deviation (SD) age: 22.5?0.68 years, height: 175.15?3.37 cm, b...

Soft braces in the treatment of Adolescent Idiopathic Scoliosis (AIS – Review of the literature and description of a new approach

Directory of Open Access Journals (Sweden)

Weiss Hans-Rudolf

2012-05-01

Full Text Available Abstract Background The use of soft braces to treat scoliosis has been described by Fischer as early as 1876. With the help of elastic straps, as the authors suggested, a corrective movement for individual curve patterns should be maintained in order to inhibit curve progression. Today this concept has been revived besides soft 3 point pressure systems. Some shortcomings have been revealed in literature in comparison with hard braces, however the concept of improving quality of life of a patient while under brace treatment should furtherly be considered as valuable. Purpose of this review is to gather the body of evidence existent for the use of soft braces and to present recent developments. Method A review of literature as available on Pub Med was performed using the key words ‘scoliosis’ and ‘soft brace’ at first. The search was expanded using ‘scoliosis’ and the known trademarks (1 ‘scoliosis’ and ‘SpineCor’, (2 ‘scoliosis’ and ‘TriaC’, (3 ‘scoliosis’ and ‘St. Etienne brace’, (4 ‘scoliosis’ and ‘Olympe’. The papers considered for inclusion were new technical descriptions, preliminary results, cohort studies and controlled studies. Results When searching for the terms ‘scoliosis’ and ‘SpineCor’: 20 papers have been found, most of them investigating a soft brace, for ‘scoliosis’ and ‘TriaC’: 7 papers displayed, for ‘scoliosis’ and ‘St. Etienne brace’: one paper displayed but not meeting the topic and for ‘scoliosis’ and ‘Olympe’: No paper displayed. Four papers found on the SpineCor™ were of prospective controlled or prospective randomized design. These papers partly presented contradictory results. Two papers were on soft Boston braces used in patients with neuromuscular scoliosis. Discussion There is a small but consistent body of evidence for the use of soft braces in the treatment of scoliosis. Contradictory results have been published for samples treated during

Evaluation of Seismic Behavior of Steel Braced Frames with Controlled Rocking System and Energy Dissipating Fuses

Directory of Open Access Journals (Sweden)

Hassan Amirzehni

2016-12-01

Full Text Available The self-centering rocking steel braced frames are new type of seismic lateral-force resisting systems that are developed with aim to limiting structural damages, minimizing residual drifts on systems and creating easy and inexpensive reconstruction capability, after sever earthquakes. In Steel braced frames with controlled rocking system, column bases on seismic resisting frame are not attached to the foundation and the frame allowed to rock freely. The task of restoring the rotated frame to its initial location is on post-tensioned cables, which attaches top of the frame to foundation. The design of post tensioned stands and braced frame members is such that during earthquakes they remain in elastic region. Seismic energy, dissipates by plastic deformations in replaceable elements on each rock of frame. In current research work, the seismic behavior of this type of lateral resisting systems is evaluated. The research conducted on a one bay steel braced frame with controlled rocking system that is analyzed using nonlinear dynamic time history analysis (NLTHA procedure. The frame is subjected to JMA-Kobe and Northridge ground motions records that are scaled to unit, 1.2 and 1.5 times of maximum considered earthquake (MCE ground motion level intensity. Extracted results show that seismic behavior of this type of lateral force resisting systems are so desirable even under MCE ground motion levels. The only anxiety is about occurring fatigue in post-tensioned strands that endangers overall stability of system.

Risk Factors for Parachute Injuries and Airborne Student Observations on the Parachute Ankle Brace

National Research Council Canada - National Science Library

Knapik, Joseph J; Spiess, Anita; Darakjy, Salima; Grier, Tyson; Manning, Fred; Livingston, Elaine; Swedler, David; Amoroso, Paul; Jones, Bruce H

2007-01-01

...) of the Defense Safety Oversight Council (DSOC) to evaluate the parachute ankle brace (PAB). Information provided by the questionnaire identified potential injury risk factors and comments on the PAB...

The Effects of Counterforce Brace Size on the Wrist Range of Motility, Pain, Grip & Wrist Extension Sterngth in Normal Subjects and Patients with Tennis Elbow

Directory of Open Access Journals (Sweden)

Ali Asghar Jameh-Bozorgi

2006-04-01

Full Text Available Objective: Counter force brace is one of the most usefull treatments for lateral opicondylitis (Tennis elbow because it decreases grip pain and increases the power of grip, power of wrist extension and Wrist Range of Motility. The purpose of this quasi experimental (repeated measurementsstudy was to determine the effect of 3 counterforce brace sizes on the wrist R.O.M, grip and wrist extension strength and pain intensity in two groups of healthy subjects and patients with tennis elbow. Materials & Methods: 18 normal subjects & 18 patients with tennis elbow were selected simple conveniently and were tested with no brace and 3 size of counterforce (1,2 and 3 inches. The R.O.M , strength and pain intensity were measured by jamar goniometry and Nicholas MMT dynamometry & VAS, respectively. Results: 1 With all sizes there was a significant decrease of R.O.M on normal subjects but no significant difference in patients. 2 There was a significant decrease of grip strength with 1-inch brace in normal subjects but a significant increase of grip strength with 2 and 3-inch brace in patiens. 3 All sizes of brace caused significant decrease of extension strength in normal subjects but increase in patients. 4All size caused significant decrease of pain intensity that was more considerable in the case of 2 and 3 inch size. Conclusion: The results shows that the counterforce brace may be considered as an effective treatment for increasing strength and decreasing pain in patients with tennis elbow.

Soft-plastic brace for lower limb fractures in patients with spinal cord injury.

Science.gov (United States)

Uehara, K; Akai, M; Kubo, T; Yamasaki, N; Okuma, Y; Tobimatsu, Y; Iwaya, T

2013-04-01

Retrospective study at a rehabilitation center. Patients with spinal cord injury, even if they are wheelchair users, sometimes suffer from fractures of the lower limb bones. As their bones are too weak to have surgery, and because a precise reduction is not required for restoration, such patients are often indicated for conservative treatment. This case series study investigated the use of a hinged, soft-plastic brace as a conservative approach to treating fractures of the lower extremities of patients with spinal cord injury. National Rehabilitation Center, Japan. Fifteen patients (male, n=10; female, n=5; average age, 52.7 years) with 19 fractures of the femur or the tibia who were treated with a newly-developed hinged, soft-plastic brace were studied. All of them used wheelchairs. We analyzed the time taken for fracture union and for wearing orthotics, degree of malalignment, femorotibial angle and side effects. The fractures in this series were caused by relatively low-energy impact. The average time taken for fracture union was 80.1 (37-189) days, and the average amount of time spent wearing orthotics was 77.9 (42-197) days. On final X-ray imaging, the average femorotibial angle was 176.9° (s.d. ±8.90), and 15° of misalignment in the sagittal plane occurred in one patient. A hinged, soft-plastic brace is a useful option as a conservative approach for treating fractures of the lower extremities in patients with spinal cord injury.

Specific exercises reduce brace prescription in adolescent idiopathic scoliosis: a prospective controlled cohort study with worst-case analysis.

Science.gov (United States)

Negrini, Stefano; Zaina, Fabio; Romano, Michele; Negrini, Alessandra; Parzini, Silvana

2008-06-01

To compare the effect of Scientific Exercises Approach to Scoliosis (SEAS) exercises with "usual care" rehabilitation programmes in terms of the avoidance of brace prescription and prevention of curve progression in adolescent idiopathic scoliosis. Prospective controlled cohort observational study. Seventy-four consecutive outpatients with adolescent idiopathic scoliosis, mean 15 degrees (standard deviation 6) Cobb angle, 12.4 (standard deviation 2.2) years old, at risk of bracing who had not been treated previously. Thirty-five patients were included in the SEAS exercises group and 39 in the usual physiotherapy group. The primary outcome included the number of braced patients, Cobb angle and the angle of trunk rotation. There were 6.1% braced patients in the SEAS exercises group vs 25.0% in the usual physiotherapy group. Failures of treatment in the worst-case analysis were 11.5% and 30.8%, respectively. In both cases the differences were statistically significant. Cobb angle improved in the SEAS exercises group, but worsened in the usual physiotherapy group. In the SEAS exercises group, 23.5% of patients improved and 11.8% worsened, while in the usual physiotherapy group 11.1% improved and 13.9% worsened. These data confirm the effectiveness of exercises in patients with scoliosis who are at high risk of progression. Compared with non-adapted exercises, a specific and personalized treatment (SEAS) appears to be more effective.

Perceptual strategies of pigeons to detect a rotational centre--a hint for star compass learning?

Directory of Open Access Journals (Sweden)

Bianca Alert

Full Text Available Birds can rely on a variety of cues for orientation during migration and homing. Celestial rotation provides the key information for the development of a functioning star and/or sun compass. This celestial compass seems to be the primary reference for calibrating the other orientation systems including the magnetic compass. Thus, detection of the celestial rotational axis is crucial for bird orientation. Here, we use operant conditioning to demonstrate that homing pigeons can principally learn to detect a rotational centre in a rotating dot pattern and we examine their behavioural response strategies in a series of experiments. Initially, most pigeons applied a strategy based on local stimulus information such as movement characteristics of single dots. One pigeon seemed to immediately ignore eccentric stationary dots. After special training, all pigeons could shift their attention to more global cues, which implies that pigeons can learn the concept of a rotational axis. In our experiments, the ability to precisely locate the rotational centre was strongly dependent on the rotational velocity of the dot pattern and it crashed at velocities that were still much faster than natural celestial rotation. We therefore suggest that the axis of the very slow, natural, celestial rotation could be perceived by birds through the movement itself, but that a time-delayed pattern comparison should also be considered as a very likely alternative strategy.

Cost effectiveness of brace, physiotherapy, or both for treatment of tennis elbow

NARCIS (Netherlands)

Struijs, P. A. A.; Korthals-de Bos, I. B. C.; van Tulder, M. W.; van Dijk, C. N.; Bouter, L. M.; Assendelft, W. J. J.

2006-01-01

BACKGROUND: The annual incidence of tennis elbow in the general population is high (1-3%). Tennis elbow often leads to limitation of activities of daily living and work absenteeism. Physiotherapy and braces are the most common treatments. OBJECTIVES: The hypothesis of the trial was that no

Aspects of the historical development of targetry for heavy ions of 0.05-2000 A centre dot MeV at GSI

CERN Document Server

Folger, H

1999-01-01

The progressively improved GSI accelerators provide beams of heavy ions from energies of 0.05-2000 A centre dot MeV at high particle intensities now. Therefore, a wide variety of common and new heavy-ion target techniques had to be installed and developed during the past 25 years to prepare and characterize self-supported or backed heavy-ion-targets of chemical elements and compounds from hydrogen (as polyethylene) to uranium. The thickness ranged from 2x10 sup - sup 6 to 20 g/cm sup 2 for beam spots of about 5 mm in diameter. Homogeneity, surface structure or individual shape had to be adapted to the needs of each experiment. Special setups were required for targets of poisonous materials, of highly enriched stable isotopes or those of radioactive species in minute amounts. The capability of thin-layer technologies was as well applied to prepare and measure stripper foils or various high-vacuum deposits for experimental or accelerator purposes. The development of different rotating target wheels and control ...

Design Optimization of Long-Span Cold-Formed Steel Portal Frames Accounting for Effect of Knee Brace Joint Configuration

OpenAIRE

Thanh Duoc Phan; James B. P. Lim; Meheron Selowara Joo; Hieng-Ho Lau

2017-01-01

The application of cold-formed steel channel sections for portal frames becomes more popular for industrial and residential purposes. Experimental tests showed that such structures with long-span up to 20 m can be achieved when knee brace joints are included. In this paper, the influence of knee brace configuration on the optimum design of long-span cold-formed steel portal frames is investigated. The cold-formed steel portal frames are designed using Eurocode 3 under ultimate limit states. A...

Efficacy of b-lynch brace suture in postpartum haemorrhage

International Nuclear Information System (INIS)

Tarique, S.; Wazir, S.; Moeen, G.

2011-01-01

Massive uncontrolled haemorrhage after childbirth is the leading cause of maternal death in developing countries. Postpartum haemorrhage is traditionally defined as blood loss of more than 500 ml after vaginal delivery and more than 1000 ml after caesarean section, but intraoperative estimation of blood loss is inaccurate. Uterine atony alone accounts for 75 - 90% of PPH. To estimate the effectiveness and safety of B-Lynch brace Suture in the management of primary postpartum haemorrhage (PPH). (author)

Behavior of concentrically loaded CFT braces connections

Directory of Open Access Journals (Sweden)

Maha M. Hassan

2014-03-01

Full Text Available Concrete filled tubes (CFTs composite columns have many economical and esthetic advantages, but the behavior of their connections is complicated. Through this study, it is aimed to investigate the performance and behavior of different connection configurations between concrete filled steel tube columns and bracing diagonals through an experimental program. The study included 12 connection subassemblies consisting of a fixed length steel tube and gusset plate connected to the tube end with different details tested under half cyclic loading. A notable effect was observed on the behavior of the connections due to its detailing changes with respect to capacity, failure mode, ductility, and stress distribution.

Human occupants in low-speed frontal sled tests: effects of pre-impact bracing on chest compression, reaction forces, and subject acceleration.

Science.gov (United States)

Kemper, Andrew R; Beeman, Stephanie M; Madigan, Michael L; Duma, Stefan M

2014-01-01

The purpose of this study was to investigate the effects of pre-impact bracing on the chest compression, reaction forces, and accelerations experienced by human occupants during low-speed frontal sled tests. A total of twenty low-speed frontal sled tests, ten low severity (∼2.5g, Δv=5 kph) and ten medium severity (∼5g, Δv=10 kph), were performed on five 50th-percentile male human volunteers. Each volunteer was exposed to two impulses at each severity, one relaxed and the other braced prior to the impulse. A 59-channel chestband, aligned at the nipple line, was used to quantify the chest contour and anterior-posterior sternum deflection. Three-axis accelerometer cubes were attached to the sternum, 7th cervical vertebra, and sacrum of each subject. In addition, three linear accelerometers and a three-axis angular rate sensor were mounted to a metal mouthpiece worn by each subject. Seatbelt tension load cells were attached to the retractor, shoulder, and lap portions of the standard three-point driver-side seatbelt. In addition, multi-axis load cells were mounted to each interface between the subject and the test buck to quantify reaction forces. For relaxed tests, the higher test severity resulted in significantly larger peak values for all resultant accelerations, all belt forces, and three resultant reaction forces (right foot, seatpan, and seatback). For braced tests, the higher test severity resulted in significantly larger peak values for all resultant accelerations, and two resultant reaction forces (right foot and seatpan). Bracing did not have a significant effect on the occupant accelerations during the low severity tests, but did result in a significant decrease in peak resultant sacrum linear acceleration during the medium severity tests. Bracing was also found to significantly reduce peak shoulder and retractor belt forces for both test severities, and peak lap belt force for the medium test severity. In contrast, bracing resulted in a significant

Radiographic evaluation of acute distal radius fracture stability: A comparative cadaveric study between a thermo-formable bracing system and traditional fiberglass casting.

Science.gov (United States)

Santoni, Brandon G; Aira, Jazmine R; Diaz, Miguel A; Kyle Stoops, T; Simon, Peter

2017-08-01

Distal radius fractures are common musculoskeletal injuries and many can be treated non-operatively with cast immobilization. A thermo-formable brace has been developed for management of such fractures, but no data exist regarding its comparative stabilizing efficacy to fiberglass casting. A worst-case distal radius fracture was created in 6 cadaveric forearms. A radiolucent loading fixture was created to apply cantilever bending/compression loads ranging from 4.5N to 66.7N across the simulated fracture in the: (1) non-stabilized, (2) braced; and (3) casted forearms, each forearm serving as its own control. Fracture fragment translations and rotations were measured radiographically using orthogonal radiographs and a 2D-3D, CT-based transformation methodology. Under 4.5N of load in the non-stabilized condition, average sagittal plane rotation and 3D center of mass translation of the fracture fragment were 12.3° and 5.3mm, respectively. At the 4.5N load step, fragment rotation with the brace (avg. 0.0°) and cast (0.1°) reduced sagittal plane rotation compared to the non-stabilized forearm (Pthermo-formable brace stabilized the fracture in a manner that was not radiographically or biomechanically different from traditional fiberglass casting. Study results support the use of the thermo-formable brace clinically. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bracing in adult with scoliosis: experience in diagnosis and classification from a 15 year prospective study of 739 patients

Directory of Open Access Journals (Sweden)

Jean Claude de Mauroy

2016-10-01

Full Text Available Abstract Background Despite the frequency of adult scoliosis, very few publications concern the conservative orthopaedic treatments. The indications have not been defined to date. The experience of a department specialized in rigid bracing allows us to consolidate and clarify diagnosis and indications as well. Methods Individual observational prospective cohort study from a database started in 1998, with selection of all 739 adult scoliosis patients for which conservative orthopaedic treatment has been proposed to, even in case of drop-out. Scoliosis treated during adolescence and monitored in adulthood are included if a new brace is prescribed. A first descriptive study of the main parameters was performed: gender, age, Cobb angle. A tentative classification according to aetiology, age and angulation is proposed. Results 1 Descriptive Data: The Ratio Female/Male is 88 %, the mean age: 56.97 ± 15.82, the mean Cobb angle: 35.58 ± 17.35. The rate of non-adherent patients not wearing the brace is 17 % (but the plaster cast before bracing was routinely proposed at the time. 2 All patients can be grouped into five diagnoses, all statistically different, according to the age and the initial Cobb angle: Rotatory dislocation: 361 cases, age: 59.73 ± 13.52 (p = 0.05, (Cobb 39.08 ± 16.59 (p = 0.02* Instability and disc disease: 150 cases, age: 46.03 ± 15.49 (p = 0.00*, Cobb: 25.29 ± 12.29 (p = 0.00* Camptocormia: 68 cases, age: 69.78 ± 12.19 (p = 0.00*, Cobb: 38.09 ± 14.23 (p = 0.25 Kyphosis TL or T: 62 cases, age: 60.73 ± 15.51 (p = 0.07, Cobb: 43.34 ± (21.48 (p = 0.00* Disabling pain: 33 cases, age: 48.36 ± 13.73 (p = 0.02*, Cobb: 36.45 ± 25.21 (p = 0.78 Treatment after surgery and in the context of a lumbar stenosis and spondylolisthesis are independent groups. Despite the wide variety of etiologies, nearly 2/3 of patients have a discal pathology like

Imaging and Manipulating Energy Transfer Among Quantum Dots at Individual Dot Resolution.

Science.gov (United States)

Nguyen, Duc; Nguyen, Huy A; Lyding, Joseph W; Gruebele, Martin

2017-06-27

Many processes of interest in quantum dots involve charge or energy transfer from one dot to another. Energy transfer in films of quantum dots as well as between linked quantum dots has been demonstrated by luminescence shift, and the ultrafast time-dependence of energy transfer processes has been resolved. Bandgap variation among dots (energy disorder) and dot separation are known to play an important role in how energy diffuses. Thus, it would be very useful if energy transfer could be visualized directly on a dot-by-dot basis among small clusters or within films of quantum dots. To that effect, we report single molecule optical absorption detected by scanning tunneling microscopy (SMA-STM) to image energy pooling from donor into acceptor dots on a dot-by-dot basis. We show that we can manipulate groups of quantum dots by pruning away the dominant acceptor dot, and switching the energy transfer path to a different acceptor dot. Our experimental data agrees well with a simple Monte Carlo lattice model of energy transfer, similar to models in the literature, in which excitation energy is transferred preferentially from dots with a larger bandgap to dots with a smaller bandgap.

Leaving the street and reconstructing lives: impact of DOTS in empowering homeless people in Tokyo, Japan.

Science.gov (United States)

Kawatsu, L; Sato, N; Ngamvithayapong-Yanai, J; Ishikawa, N

2013-07-01

Since 2000, the Public Health Centre (PHC) in Shinjuku, an area of Tokyo with one of the largest homeless populations in Japan, has been implementing PHC-based DOTS treatment for homeless tuberculosis (TB) patients, with much epidemiological success. Anecdotal evidence indicates that homeless patients treated under DOTS have experienced various positive changes. However, this experience has not yet been systematically analysed. To explore the changes experienced by homeless TB patients, and to discuss the possible role of PHC-based DOTS treatment in effecting these changes. A qualitative study via in-depth interviews with 18 ex-homeless patients who completed DOTS-based treatment at Shinjuku City PHC. The data were analysed using the interpretive content analysis method. The various changes experienced by the participants were categorised into five sub-categories of empowerment, including improved mental health and interpersonal relationships. Some of these changes were attributable to the participants undergoing PHC-based DOTS, which, by addressing their various emotional needs, helped to trigger patient empowerment. Based on our findings, a model of empowerment using PHC-based DOTS was constructed. PHC-based DOTS not only successfully controlled TB, it also empowered homeless patients by addressing their emotional needs. The interpersonal skills of the nurses played a critical role in this process.

Measurements of the critical parameters for {l_brace}xNH{sub 3} + (1 - x)H{sub 2}O{r_brace} with x = (0.9098, 0.7757, 0.6808)

Energy Technology Data Exchange (ETDEWEB)

Sakabe, A.; Arai, D. [Centre for Multiscale Mechanics and Mechanical Systems, Keio University, Yokohama 223-8522 (Japan); Miyamoto, H. [Department of Mechanical Systems Engineering, Toyama Prefectural University, Imizu 939-0398 (Japan)], E-mail: miyamoto@pu-toyama.ac.jp; Uematsu, M. [Centre for Multiscale Mechanics and Mechanical Systems, Keio University, Yokohama 223-8522 (Japan)

2008-10-15

Measurements of the critical parameters for {l_brace}xNH{sub 3} + (1 - x)H{sub 2}O{r_brace} with x = (0.9098, 0.7757, 0.6808) were carried out by using a metal-bellows variable volumometer with an optical cell. The expanded uncertainties (k = 2) in temperature, pressure, density, and composition measurements have been estimated to be less than 3.2 mK, 3.2 kPa, 0.3 kg . m{sup -3}, and 8.8 . 10{sup -4}, respectively. In each mole fraction, the critical temperature T{sub c} was first determined on the basis of the intensity of the critical opalescence. The critical pressure p{sub c} and critical density {rho}{sub c} were then determined as the point at which the meniscus disappears on the isotherm at T = T{sub c}. The expanded uncertainties (k = 2) in the present critical parameters have also been estimated. Comparisons of the present values with the literature data as well as the calculated values afforded using the equation of state are also presented.

Fabrication of a new samarium(III) ion-selective electrode based on 3-{l_brace}[2-oxo-1(2h)-acenaphthylenyliden]amino{r_brace}-2-thioxo -1,3-thiazolidin-4-one

Energy Technology Data Exchange (ETDEWEB)

Zamani, Hassan Ali [Islamic Azad University, Quchan (Iran, islamic Republic of). Quchan Branch. Dept. of Chemistry]. E-mail: haszamani@yahoo.com; Ganjali, Mohammad Reza [Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of). Endocrine and Metabolism Research Center; Adib, Mehdi [University of Tehran, Tehran (Iran, Islamic Republic of). Faculty of Chemistry. Center of Excellence in Electrochemistry

2007-07-01

This paper introduces the development of an original PVC membrane electrode, based on 3-{l_brace}[2-oxo-1(2H)-acenaphthylenyliden]amino{r_brace}-2-thioxo-1,3-thiazolidin-4-one (ATTO) which has revealed to be a suitable carrier for Sm{sup 3+} ions. The resulting data illustrated that the electrode shows a Nernstian slope of 19.3 {+-} 0.6 mV per decade for Sm{sup 3+} ions over a broad working concentration range of 1.0 X 10{sup -6} to 1.0 X 10{sup -1} mol L{sup -1}. The lower detection limit was found to be equal to (5.5{+-} 0.3) X 10{sup -7} mol L{sup -}'1 in the pH range of 3.5-7.5, and the response time was very short ({approx}10 s). The potentiometric sensor displayed good selectivities for a number of cations such as alkali, alkaline earth, transition and heavy metal ions. (author)

Benefit-Risk Assessment, Communication, and Evaluation (BRACE) throughout the life cycle of therapeutic products: overall perspective and role of the pharmacoepidemiologist.

Science.gov (United States)

Radawski, Christine; Morrato, Elaine; Hornbuckle, Kenneth; Bahri, Priya; Smith, Meredith; Juhaeri, Juhaeri; Mol, Peter; Levitan, Bennett; Huang, Han-Yao; Coplan, Paul; Li, Hu

2015-12-01

Optimizing a therapeutic product's benefit-risk profile is an on-going process throughout the product's life cycle. Different, yet related, benefit-risk assessment strategies and frameworks are being developed by various regulatory agencies, industry groups, and stakeholders. This paper summarizes current best practices and discusses the role of the pharmacoepidemiologist in these activities, taking a life-cycle approach to integrated Benefit-Risk Assessment, Communication, and Evaluation (BRACE). A review of the medical and regulatory literature was performed for the following steps involved in therapeutic benefit-risk optimization: benefit-risk evidence generation; data integration and analysis; decision making; regulatory and policy decision making; benefit-risk communication and risk minimization; and evaluation. Feedback from International Society for Pharmacoepidemiology members was solicited on the role of the pharmacoepidemiologist. The case example of natalizumab is provided to illustrate the cyclic nature of the benefit-risk optimization process. No single, globally adopted benefit-risk assessment process exists. The BRACE heuristic offers a way to clarify research needs and to promote best practices in a cyclic and integrated manner and highlight the critical importance of cross-disciplinary input. Its approach focuses on the integration of BRACE activities for risk minimization and optimization of the benefit-risk profile. The activities defined in the BRACE heuristic contribute to the optimization of the benefit-risk profile of therapeutic products in the clinical world at both the patient and population health level. With interdisciplinary collaboration, pharmacoepidemiologists are well suited for bringing in methodology expertise, relevant research, and public health perspectives into the BRACE process. Copyright © 2015 John Wiley & Sons, Ltd.

Clinical assessment of the efficacy of SpineCor brace in the correction of postural deformities in the course of idiopathic scoliosis.

Science.gov (United States)

Plewka, Barbara; Sibiński, Marcin; Synder, Marek; Witoński, Dariusz; Kołodziejczyk-Klimek, Katarzyna; Plewka, Michał

2013-03-26

The objective of the study was to perform a clinical, comparative assessment of the degree of postural deformities before and after the treatment of idiopathic scoliosis in patients treated with SpineCor brace compared to the control group. A group of 90 children with idiopathic scoliosis (including 74 girls) at the average age of 12.2 was subject to prospective observation. Average pre-treatment Cobb angle was 24.9° in the thoracic spine and 25.8° in the lumbar spine. The group actively treated with the SpineCor brace consisted of 45 children, while the control group consisted of the remaining 45 children with the natural course of the disease. Both groups did not differ significantly in terms of age, gender, height, body weight, Risser sign of skeletal maturity and baseline clinical and radiological parameters of scoliosis. Significant reduction of rib hump was observed upon 2-year SpineCor brace treatment (P=0.04) compared to the group treated by physiotherapy only (P=0.91). Similarly, improvement in lumbar prominence was observed in the actively treated group (P=0.009), with a trend towards worse results in the control group (P=0.07) In the group treated with the SpineCor brace, significant reduction in pectoral and hamstring muscle contractures as well as reduction in shoulder asymmetry and reduction in anterior and posterior vertical deviation were observed. Treatment using the SpineCor dynamic brace leads to a clinical improvement in posture, particularly to reduction in rib hump, lumbar prominence and muscular contractures.

Evaluating the Ergonomic Benefit of a Wrist Brace on Wrist Posture, Muscle Activity, Rotational Stiffness, and Peak Shovel-Ground Impact Force During a Simulated Tree-Planting Task.

Science.gov (United States)

Sheahan, Peter J; Cashaback, Joshua G A; Fischer, Steven L

2017-09-01

Background Tree planters are at a high risk for wrist injury due to awkward postures and high wrist loads experienced during each planting cycle, specifically at shovel-ground impact. Wrist joint stiffness provides a measure that integrates postural and loading information. Objective The purpose of this study was to evaluate wrist joint stiffness requirements at the instant of shovel-ground impact during tree planting and determine if a wrist brace could alter muscular contributions to wrist joint stiffness. Method Planters simulated tree planting with and without wearing a brace on their planting arm. Surface electromyography (sEMG) from six forearm muscles and wrist kinematics were collected and used to calculate muscular contributions to joint rotational stiffness about the wrist. Results Wrist joint stiffness increased with brace use, an unanticipated and negative consequence of wearing a brace. As a potential benefit, planters achieved a more neutrally oriented wrist angle about the flexion/extension axis, although a less neutral wrist angle about the ulnar/radial axis was observed. Muscle activity did not change between conditions. Conclusion The joint stiffness analysis, combining kinematic and sEMG information in a biologically relevant manner, revealed clear limitations with the interface between the brace grip and shovel handle that jeopardized the prophylactic benefits of the current brace design. This limitation was not as evident when considering kinematics and sEMG data independently. Application A neuromechanical model (joint rotational stiffness) enhanced our ability to evaluate the brace design relative to kinematic and sEMG parameter-based metrics alone.

Effect of Semi-Rigid and Soft Ankle Braces on Static and Dynamic Postural Stability in Young Male Adults

Directory of Open Access Journals (Sweden)

Noriaki Maeda, Yukio Urabe, Shogo Tsutsumi, Shuhei Numano, Miho Morita, Takuya Takeuchi, Shou Iwata, Toshiki Kobayashi

2016-06-01

Full Text Available Ankle braces have been suggested to protect ankle joints from a sprain by restricting inversion and improving proprioception. However, the difference in effects between a semi-rigid brace and a soft brace regarding dynamic postural control after landing is not known. The aim of the present study was to compare the effect of soft (SB and semi-rigid (SRB ankle braces on static and dynamic postural stability in healthy young men. Altogether, 21 male adults (mean age 24.0 ± 1.5 years were assessed for one leg while wearing non-brace (NB, SB or SRB. Balance in single-limb stance on a single-force platform with open eyes and closed eyes were assessed for the non-dominant leg under SB, SRB, and NB conditions. Locus length/second (mm/s and the enveloped area (mm·s-2 surrounded by the circumference of the wave pattern during postural sway were calculated. For assessing dynamic postural stability, the participant jumped and landed on one leg on a force platform, and the Dynamic Postural Stability Index (DPSI and the maximum vertical ground reaction force (vGRFmax were measured. The data were compared among the three conditions with repeated-measures analysis of variance. The correlations between locus length/second, enveloped area, DPSI values (DPSI, Anterior-Posterior Stability Index, Medial-Lateral Stability Index, and Vertical Stability Index, and vGRFmax were then calculated. The results indicated that locus length/second and enveloped area with open eyes and closed eyes were not significantly different for each condition. However, a significant lower in the DPSI and Vertical Stability Index were observed with the SRB in comparison to the SB and NB. A significant improvement in vGRFmax was also observed with the SRB in comparison to NB. SRB demonstrated a positive effect on dynamic postural stability after landing on a single leg and may improve balance by increasing dynamic postural stability.

Bracing system of the reflecting sheets making up an insulating pile

International Nuclear Information System (INIS)

Carr, R.W.

1976-01-01

In order to reduce heat and radiation losses, the body of nuclear reactors and the connected pipe work are encased in reflecting and insulating piles of thin spaced sheets of aluminium or stainless steel. These spaced sheets are then encased in thicker and more solid internal and external shells. The piles and shells are generally shaped to follow the contour of the reactor and connected piping. It is therefore necessary to have available a study bracing system to keep the pile intact during the various handling and assembly operations. The fastening system must also exert an effect on the edge of the pile to prevent the sheets making it up from shifting in relation to each other. The description is given of a fastening system that includes an oblong section to be fitted along the edges of the piles up sheets; bracing substantially perpendicular to the oblong section, to space the sheets of the stack in pairs; and a maintaining system, normally perpendicular to the oblong section, to enable the fastener to be clipped to the edge of the sheets by bending it around the edge of each sheet of the pile [fr

50 CFR Figure 15 to Part 223 - Weedless TED Brace Bar Description

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Weedless TED Brace Bar Description 15 Figure 15 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES Pt. 223, Fig. 15 Figure 15 to Part 223...

Design, testing and control of a magnetorheological actuator for assistive knee braces

International Nuclear Information System (INIS)

Chen, J Z; Liao, W H

2010-01-01

This paper is aimed at developing a smart actuator for assistive knee braces to provide assistance to disabled or elderly people with mobility problems. A magnetorheological (MR) actuator is developed to be used in assistive knee braces to provide controllable torque. The MR actuator can work as a brake or a clutch. When active torque is needed, the DC motor works and the MR actuator functions as a clutch to transfer the torque generated by the motor to the leg; when passive torque is desired, the DC motor is turned off and the MR actuator functions as a brake to provide controllable passive torque. The prototype of the developed MR actuator is fabricated and experiments are carried out to investigate the characteristics of the MR actuator. The results show that the MR actuator is able to provide sufficient torque needed for normal human activities. Adaptive control is proposed for controlling the MR actuator. Anti-windup strategy is used to achieve better control performance. Experiments on the MR actuator under control are also performed to study the torque tracking ability of the system

Contribution of dot-blot assay to the diagnosis and management of myositis: a three-year practice at a university hospital centre.

Science.gov (United States)

Martel, Clothilde; Vignaud, Guillaume; Liozon, Eric; Magy, Laurent; Gallouedec, Gael; Ly, Kim; Bezanahary, Holly; Cypierre, Anne; Lapébie, François-Xavier; Palat, Sylvain; Gondran, Guillaume; Jauberteau, Marie-Odile; Fauchais, Anne-Laure

2016-01-01

Idiopathic inflammatory myopathies (IIM) are heterogeneous autoimmune diseases with wide clinical spectrum that may lead to delayed diagnosis. The aim of this study was to examine the impact of IIM-specific dot-blot assay on diagnostic process of patients presenting with muscular or systemic symptoms evocating of IIM. We collected all the prescriptions of an IIM specific dot-blot assay (8 autoantigens including Jo-1, PL-7, PL-12, SRP, Mi-2, Ku, PM/Scl and Scl-70) over a 38-month period. 316 myositis dot-blot assays (MSD) were performed in 274 patients (156 women, mean age 53±10.6 years) referring for muscular and/or systemic symptoms suggesting IIM. The timing of dot prescription through the diagnostic process was highly variable: without (35%), concomitantly (16%) or after electromyographic studies (35%). Fifty-nine patients (22%) had IIM according to Bohan and Peter's criteria. Among them, 29 (49%) had positive dot (8 Jo-1, 6 PM-Scl, 5 PL-12, 5 SRP, 2 Mi-2, 2 PL-7 and 1 Ku). Various other diagnoses were performed including 35 autoimmune disease or granulomatosis (12%), 19 inflammatory rheumatic disease (7%), 16 non inflammatory muscular disorders (6%), 10 drug-induced myalgia (4%), 11 infectious myositis (4%). Except 11 borderline SRP results and one transient PM-Scl, MSD was positive only in one case of IIM. Dot allowed clinicians to correct diagnosis in 4 cases and improved the diagnosis of IIM subtypes in 4 cases. This study reflects the interest of myositis dot in the rapid diagnosis process of patients with non-specific muscular symptoms leading to various diagnoses including IIM.

Outcome in adolescent idiopathic scoliosis after brace treatment and surgery assessed by means of the Scoliosis Research Society Instrument 24.

Science.gov (United States)

Weigert, Karen Petra; Nygaard, Linda Marie; Christensen, Finn Bjarke; Hansen, Ebbe Stender; Bünger, Cody

2006-07-01

A retrospectively designed long-term follow-up study of adolescent idiopathic scoliosis (AIS) patients who had completed treatment, of at least 2 years, by means of brace, surgery, or both brace and surgery. This study is to assess the outcome after treatment for AIS by means of the Scoliosis Research Society Outcome Instrument 24 (SRS 24). One hundred and eighteen AIS patients (99 females and 19 males), treated at the Aarhus University Hospital from January 1, 1987 to December 31, 1997, were investigated with at least 2 years follow-up at the time of receiving a posted self-administered questionnaire. Forty-four patients were treated with Boston brace (B) only, 41 patients had surgery (S), and 33 patients were treated both with brace and surgery (BS). The Cobb angles of the three treatment groups did not differ significantly after completed treatment. The outcome in terms of the total SRS 24 score was not significantly different among the three groups. B patients had a significantly better general (not treatment related) self-image and higher general activity level than the total group of surgically treated patients, while surgically treated patients scored significantly better in post-treatment self-image and satisfaction. Comparing B with BS we found a significantly higher general activity level in B patients, while the BS group had significantly higher satisfaction. There were no significant differences between BS and S patients in any of the domain scores. All treatment groups scored "fair or better" in all domain scores of the SRS 24 questionnaire, except in post-treatment function, where all groups scored worse than "fair". Improvement of appearance by means of surgical correction increases mean scores for post-treatment self-image and post-treatment satisfaction. Double-treatment by brace and surgery does not appear to jeopardize a good final outcome.

Electronic transport through a quantum dot chain with strong dot-lead coupling

International Nuclear Information System (INIS)

Liu, Yu; Zheng, Yisong; Gong, Weijiang; Gao, Wenzhu; Lue, Tianquan

2007-01-01

By means of the non-equilibrium Green function technique, the electronic transport through an N-quantum-dot chain is theoretically studied. By calculating the linear conductance spectrum and the local density of states in quantum dots, we find the resonant peaks in the spectra coincides with the eigen-energies of the N-quantum-dot chain when the dot-lead coupling is relatively weak. With the increase of the dot-lead coupling, such a correspondence becomes inaccurate. When the dot-lead coupling exceeds twice the interdot coupling, such a mapping collapses completely. The linear conductance turn to reflect the eigen-energies of the (N-2)- or (N-1)-quantum dot chain instead. The two peripheral quantum dots do not manifest themselves in the linear conductance spectrum. More interestingly, with the further increase of the dot-lead coupling, the system behaves just like an (N-2)- or (N-1)-quantum dot chain in weak dot-lead coupling limit, since the resonant peaks becomes narrower with the increase of dot-lead coupling

Printer model for dot-on-dot halftone screens

Science.gov (United States)

Balasubramanian, Raja

1995-04-01

A printer model is described for dot-on-dot halftone screens. For a given input CMYK signal, the model predicts the resulting spectral reflectance of the printed patch. The model is derived in two steps. First, the C, M, Y, K dot growth functions are determined which relate the input digital value to the actual dot area coverages of the colorants. Next, the reflectance of a patch is predicted as a weighted combination of the reflectances of the four solid C, M, Y, K patches and their various overlays. This approach is analogous to the Neugebauer model, with the random mixing equations being replaced by dot-on-dot mixing equations. A Yule-Neilsen correction factor is incorporated to account for light scattering within the paper. The dot area functions and Yule-Neilsen parameter are chosen to optimize the fit to a set of training data. The model is also extended to a cellular framework, requiring additional measurements. The model is tested with a four color xerographic printer employing a line-on-line halftone screen. CIE L*a*b* errors are obtained between measurements and model predictions. The Yule-Neilsen factor significantly decreases the model error. Accuracy is also increased with the use of a cellular framework.

Conservative treatment for pediatric lumbar spondylolysis to achieve bone healing using a hard brace: what type and how long?: Clinical article.

Science.gov (United States)

Sairyo, Koichi; Sakai, Toshinori; Yasui, Natsuo; Dezawa, Akira

2012-06-01

Various kinds of trunk braces have been used to achieve bone healing in cases of pediatric lumbar spondylolysis. However, the optimal brace for achieving bone healing is unclear. The purpose of the present study was to determine in what types of spondylolysis bone healing can be achieved and how long it takes. In this prospective study, 63 pars interarticularis defects (spondylolysis) among 37 patients who were younger than 18 years (mean 13.5 ± 2.7 years) were treated using a hard brace. The youngest patient was 8 years old. Based on the results of CT scanning, the lyses were classified into 3 categories: early, progressive, and terminal defects. Progressive defects were further divided into 2 types according to STIR MRI findings: those with high signal intensity at the adjacent pedicle and those with low signal intensity (that is, a normal appearance). A hard brace, such as a molded plastic thoracolumbosacral orthosis, was used to immobilize the trunk. Approximately every 3 months, CT scanning was performed to evaluate bone healing until approximately 6 months. The union rates were 94%, 64%, 27%, and 0% for the early, progressive with high signal intensity, progressive with low signal intensity, and terminal defects, respectively. It was noted that no terminal defect was healed using conservative treatment. The mean time to healing among the defects that showed bone healing was 3.2, 5.4, and 5.7 months for the early, progressive with high signal intensity, and progressive with low signal intensity groups, respectively. Patients with early-stage defects are the best candidates for conservative treatment with a hard brace because more than 90% of such cases can be healed in 3 months.

The quantum mechanical description of the dot-dot interaction in ionic colloids

International Nuclear Information System (INIS)

Morais, P.C.; Qu, Fanyao

2007-01-01

In this study the dot-dot interaction in ionic colloids is systematically investigated by self-consistently solving the coupled Schroedinger and Poisson equations in the frame of finite difference method (FDM). In a first approximation the interacting two-dot system (dimer) is described using the picture of two coupled quantum wells. It was found that the dot-dot interaction changes the colloid characteristic by changing the hopping coefficient (t) and consequently the nanodot surface charge density (σ). The hopping coefficient and the surface charge density were investigated as a function of the dot size and dot-dot distance

Effect of kinesiotaping, non-elastic taping and bracing on segmental foot kinematics during drop landing in healthy subjects and subjects with chronic ankle instability.

Science.gov (United States)

Kuni, B; Mussler, J; Kalkum, E; Schmitt, H; Wolf, S I

2016-09-01

To evaluate the effects of kinesiotape, non-elastic tape, and soft brace on segmental foot kinematics during drop landing in subjects with chronic ankle instability and healthy subjects. Controlled study with repeated measurements. Three-dimensional motion analysis laboratory. Twenty participants with chronic ankle instability and 20 healthy subjects. The subjects performed drop landings with 17 retroreflective markers on the foot and lower leg in four conditions: barefoot, with kinesiotape, with non-elastic tape and with a soft brace. Ranges of motion of foot segments using a foot measurement method. In participants with chronic ankle instability, midfoot movement in the frontal plane (inclination of the medial arch) was reduced significantly by non-elastic taping, but kinesiotaping and bracing had no effect. In healthy subjects, both non-elastic taping and bracing reduced that movement. In both groups, non-elastic taping and bracing reduced rearfoot excursion in inversion/eversion significantly, which indicates a stabilisation effect. No such effect was found with kinesiotaping. All three methods reduced maximum plantar flexion significantly. Non-elastic taping stabilised the midfoot best in patients with chronic ankle instability, while kinesiotaping did not influence foot kinematics other than to stabilise the rearfoot in the sagittal plane. ClinicalTrials.gov NCT01810471. Copyright © 2015 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Outcome in adolescent idiopathic scoliosis after brace treatment and surgery assessed by means of the Scoliosis Research Society Instrument 24

OpenAIRE

Weigert, Karen Petra; Nygaard, Linda Marie; Christensen, Finn Bjarke; Hansen, Ebbe Stender; Bünger, Cody

2005-01-01

A retrospectively designed long-term follow-up study of adolescent idiopathic scoliosis (AIS) patients who had completed treatment, of at least 2 years, by means of brace, surgery, or both brace and surgery. This study is to assess the outcome after treatment for AIS by means of the Scoliosis Research Society Outcome Instrument 24 (SRS 24). One hundred and eighteen AIS patients (99 females and 19 males), treated at the Aarhus University Hospital from January 1, 1987 to December 31, 1997, were...

Quantum dots

International Nuclear Information System (INIS)

Kouwenhoven, L.; Marcus, C.

1998-01-01

Quantum dots are man-made ''droplets'' of charge that can contain anything from a single electron to a collection of several thousand. Their typical dimensions range from nanometres to a few microns, and their size, shape and interactions can be precisely controlled through the use of advanced nanofabrication technology. The physics of quantum dots shows many parallels with the behaviour of naturally occurring quantum systems in atomic and nuclear physics. Indeed, quantum dots exemplify an important trend in condensed-matter physics in which researchers study man-made objects rather than real atoms or nuclei. As in an atom, the energy levels in a quantum dot become quantized due to the confinement of electrons. With quantum dots, however, an experimentalist can scan through the entire periodic table by simply changing a voltage. In this article the authors describe how quantum dots make it possible to explore new physics in regimes that cannot otherwise be accessed in the laboratory. (UK)

NMR investigation on isotope effect of glycinium phosphite H sub 3 NCH sub 2 COOH centre dot H sub 2 PO sub 3

CERN Document Server

Ishibashi, T

2003-01-01

The motions of the phosphite anions and glycinium cations in H sub 3 NCH sub 2 COOH centre dot H sub 2 PO sub 3 (GPI) and its deuterated analogue (DGPI) were investigated by sup 1 H, sup 1 sup 3 C and sup 3 sup 1 P spin-lattice relaxation times T sub 1. For both GPI and DGPI, T sub 1 's of the sup 1 H, sup 1 sup 3 C and sup 3 sup 1 P nuclei reflect the amino rotation, methylene libration and motion of the phosphite anions, respectively. Activation energies obtained from T sub 1 's of sup 1 H, sup 1 sup 3 C and sup 3 sup 1 P nuclei are 28.6(2), 26.0(4) and 26.2(4) kJ/mol for GPI and are 34.9(6), 27(1), 47(2) kJ/mol for DGPI, respectively. The deuterium substitution increases E sub a for the motion influenced by the hydrogen bonding. In all the observed motions, correlation times of DGPI are larger than those of GPI. (author)

Effect of different uranium compounds on the properties of U-Pt-Y-Ba-O double-perovskite pinning centres in textured Y-Ba-Cu-O superconductor

Energy Technology Data Exchange (ETDEWEB)

Sawh, Ravi-Persad; Weinstein, Roy; Parks, Drew; Gandini, Alberto [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Texas Center for Superconductivity and Advanced Materials, University of Houston, Houston, TX 77204-5005 (United States)

2005-02-01

An experiment was performed to test the effect of different uranium compounds on the properties of chemical pinning centres. UO{sub 2}, UO{sub 3}, and UO{sub 4}{center_dot}2H{sub 2}O wereadmixed to Y 123+Pt, and textured. Tests of J{sub c} via measurements of trapped field (B{sub trap}) indicate a clear dependence of B{sub trap} on the U compound admixed to create the pinning centres. In all three cases there is a monotonic increase in B{sub trap} as the mass (M{sub U}) of U is increased. However, the magnitude of the increase in B{sub trap} depends on the admixed U compound. The highest increase in B{sub trap} is measured in samples doped with UO{sub 4}{center_dot}2H{sub 2}O, and the lowest is obtained in samples doped with UO{sub 2}. Microstructure studies indicate that the composition of the U-rich pinning deposits is the same in all three cases, i.e. all are the previously identified (U{sub 0.6}Pt{sub 0.4})Y Ba{sub 2}O{sub 6} compound. The primary difference among the three types of samples is that the size of the U-Pt-Y-Ba-O pinning deposits depends on the admixed U compound. While all are in the nanometre domain, the diameter of these deposits was markedly larger in UO{sub 2} doped samples than in UO{sub 3} doped samples, and smallest in UO{sub 4}{center_dot}2H{sub 2}O doped samples. Because some form of poisoning limits the amount of U that can be added to create pinning centres, to M{sub U} {approx}1 wt%, smaller deposits result in a greater number of pinning centres. We conclude that UO{sub 4}{center_dot}2H{sub 2}O is more effective than either UO{sub 3} or UO{sub 2} in the formation of U-Pt-Y-Ba-O pinning centres because of diminished pinning centre size, and consequent increase in pinning centre density.

A highly efficient single-photon source based on a quantum dot in a photonic nanowire

DEFF Research Database (Denmark)

Claudon, Julien; Bleuse, Joel; Malik, Nitin Singh

2010-01-01

–4 or a semiconductor quantum dot5–7. Achieving a high extraction efficiency has long been recognized as a major issue, and both classical solutions8 and cavity quantum electrodynamics effects have been applied1,9–12. We adopt a different approach, based on an InAs quantum dot embedded in a GaAs photonic nanowire......The development of efficient solid-state sources of single photons is a major challenge in the context of quantum communication,optical quantum information processing and metrology1. Such a source must enable the implementation of a stable, single-photon emitter, like a colour centre in diamond2...

Record Charge Carrier Diffusion Length in Colloidal Quantum Dot Solids via Mutual Dot-To-Dot Surface Passivation.

Science.gov (United States)

Carey, Graham H; Levina, Larissa; Comin, Riccardo; Voznyy, Oleksandr; Sargent, Edward H

2015-06-03

Through a combination of chemical and mutual dot-to-dot surface passivation, high-quality colloidal quantum dot solids are fabricated. The joint passivation techniques lead to a record diffusion length for colloidal quantum dots of 230 ± 20 nm. The technique is applied to create thick photovoltaic devices that exhibit high current density without losing fill factor. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Use of a shoulder abduction brace after arthroscopic rotator cuff repair: A study on gait performance and falls.

Science.gov (United States)

Sonoda, Yuma; Nishioka, Takashi; Nakajima, Ryo; Imai, Shinji; Vigers, Piers; Kawasaki, Taku

2018-04-01

Fall prevention is essential in patients after arthroscopic rotator cuff repair because of the high risk of re-rupture. However, there are no reports related to falls that occur during the early postoperative period, while the affected limb is immobilized. This study assessed gait performance and falls in patients using a shoulder abduction brace after arthroscopic rotator cuff repair. Prospective cohort and postoperative repeated measures. This study included 29 patients (mean age, 67.1 ± 7.4 years) who underwent arthroscopic rotator cuff repair followed by rehabilitation. The timed up and go test, Geriatric Depression Scale, and Falls Efficacy Scale were measured, and the numbers of falls were compared between those shoulder abduction brace users and patients who had undergone total hip or knee arthroplasty. In arthroscopic rotator cuff repair patients, there were significant improvements in timed up and go test and Geriatric Depression Scale, but no significant differences in Falls Efficacy Scale, between the second and fifth postoperative weeks ( p rotator cuff repair patients fell more often than patients with total hip arthroplasty or total knee arthroplasty during the same period. The findings suggest that rehabilitation in arthroscopic rotator cuff repair patients is beneficial, but decreased gait performance due to the immobilizing shoulder abduction brace can lead to falls. Clinical relevance Although rehabilitation helps motor function and mental health after arthroscopic rotator cuff repair, shoulder abduction brace use is associated with impaired gait performance, high Falls Efficacy Scale scores, and risk of falls, so awareness of risk factors including medications and lower limb dysfunctions is especially important after arthroscopic rotator cuff repair.

Design Optimization of Long-Span Cold-Formed Steel Portal Frames Accounting for Effect of Knee Brace Joint Configuration

Directory of Open Access Journals (Sweden)

Thanh Duoc Phan

2017-12-01

Full Text Available The application of cold-formed steel channel sections for portal frames becomes more popular for industrial and residential purposes. Experimental tests showed that such structures with long-span up to 20 m can be achieved when knee brace joints are included. In this paper, the influence of knee brace configuration on the optimum design of long-span cold-formed steel portal frames is investigated. The cold-formed steel portal frames are designed using Eurocode 3 under ultimate limit states. A novel method in handling design constraints integrated with genetic algorithm is proposed for searching the optimum design of cold-formed steel portal frames. The result showed that the proposed routine for design optimization effectively searched the near global optimum solution with the computational time is approximate 50% faster than methods being popularly used in literature. The optimum configuration for knee brace joint can reduce the section size of rafter and so the lighter frame could be obtained especially for long-span portal frame. The minimum weight of main frame obtained from optimization process is approximate 19.72% lighter than a Benchmark Frame used in the full-scale experimental test.

Nonlinear Dot Plots.

Science.gov (United States)

Rodrigues, Nils; Weiskopf, Daniel

2018-01-01

Conventional dot plots use a constant dot size and are typically applied to show the frequency distribution of small data sets. Unfortunately, they are not designed for a high dynamic range of frequencies. We address this problem by introducing nonlinear dot plots. Adopting the idea of nonlinear scaling from logarithmic bar charts, our plots allow for dots of varying size so that columns with a large number of samples are reduced in height. For the construction of these diagrams, we introduce an efficient two-way sweep algorithm that leads to a dense and symmetrical layout. We compensate aliasing artifacts at high dot densities by a specifically designed low-pass filtering method. Examples of nonlinear dot plots are compared to conventional dot plots as well as linear and logarithmic histograms. Finally, we include feedback from an expert review.

NaPdPS{sub 4} and RbPdPS{sub 4}: systems with infinite straight ((1)/({infinity}))[PdPS{sub 4}]{sup -} chains soluble in polar solvents and the structure of cubic RbPdPS{sub 4}{l_brace}Rb{sub 0.33}P{sub 0.4}S{sub 2.23}O{sub x}{r_brace}

Energy Technology Data Exchange (ETDEWEB)

Coste, Servane; Hanko, Jason; Bujoli-Doeuff, Martine; Louarn, Guy; Evain, Michel; Brec, Raymond; Alonso, Bruno; Jobic, S; Kanatzidis, Mercouri G

2003-11-01

The synthesis, crystal structures, chemical and spectroscopic properties of NaPdPS{sub 4}, RbPdPS{sub 4}, and RbPdPS{sub 4}{l_brace}Rb{sub 0.33}P{sub 0.4}S{sub 2.23}O{sub x}{r_brace} are described. NaPdPS{sub 4}, RbPdPS{sub 4}, are isostructural and crystallize in the tetragonal system I4/mcm with cell parameters a=7.3074(8) A, c=12.2308(14) A and a=8.2954(3) A, c=12.2284(4) A respectively. RbPdPS{sub 4}{l_brace}Rb{sub 0.33}P{sub 0.4}S{sub 2.23}O{sub x}{r_brace} is cubic, space group Pm-3n and a=12.0042(2) A. All compounds contain the same ((1)/({infinity}))[PdPS{sub 4}]{sup -} chains made of alternating square planar Pd{sup 2+} cations and tetrahedral [PS{sub 4}]{sup 3-} anions. RbPdPS{sub 4}{l_brace}Rb{sub 0.33}P{sub 0.4}S{sub 2.23}O{sub x}{r_brace} contains co-crystallized highly disordered molecular species encapsulated within [Rb{sub 8}] cubic cavities. Spectroscopic solid state {sup 31}P NMR, infrared and Raman data as well as elemental analysis suggest that these species could be S{sub n}{sup 2-} (n=3 or 4) anions and possibly cationic [P{sub 4}S{sub 6}O]{sup 6+} fragments. NaPdPS{sub 4} and RbPdPS{sub 4} exhibit exfoliative dissolution in polar solvents giving rise to solutions that show signs of complex fluid behavior.

SUPER-CAPACITOR APPLICATION IN ELECTRICAL POWER CABLE TESTING FACILITIES IN THERMAL ENDURANCE AND MECHANICAL BRACING TESTS

Directory of Open Access Journals (Sweden)

I. V. Oleksyuk

2015-01-01

Full Text Available The current-carrying cores of the electrical power cables should be resistant to effects of short-circuit currents whose values depend on the material of the core, its cross-sectional area, cable insulation properties, environment temperature, and the duration of the short-circuit current flow (1 and 3–4 sec. when tested for thermal endurance and mechanical bracing. The facilities for testing the 10 kV aluminum core cables with short-circuit current shall provide mechanical-bracing current 56,82 kA and thermal endurance current 11,16 kA. Although capacitors provide such values of the testing currents to the best advantage, utilizing conventional capacitor-units will involve large expenditures for erecting and  running a separate building. It is expedient to apply super-capacitors qua the electric power supply for testing facilities, as they are capacitors with double-electrical layer and involve the current values of tens of kilo-amperes.The insulation voltage during short-circuit current testing being not-standardized, it is not banned to apply voltages less than 10 kV when performing short-circuit thermal endurance and mechanical bracing tests for electrical power cables of 10 kV. The super-capacitor voltage variation-in-time graph consists of two regions: capacitive and resistive. The capacitive part corresponds to the voltage change consequent on the energy change in the super-capacitors. The resistive part shows the voltage variation due to the active resistance presence in the super-capacitor.The author offers the algorithm determining the number of super capacitors requisite for testing 10 kV-electrical power cables with short-circuit currents for thermal endurance and mechanical bracing. The paper shows that installation of super-capacitors in the facilities testing the cables with short-circuit currents reduces the area needed for the super-capacitors in comparison with conventional capacitors more than by one order of magnitude.

Uranium diphosphonates templated by interlayer organic amines

Energy Technology Data Exchange (ETDEWEB)

Nelson, Anna-Gay D., E-mail: nelsoa@umich.edu [Department of Civil Engineering and Geological Sciences, University of Notre Dame, IN 46556 (United States); Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005 (United States); Alekseev, Evgeny V. [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Juelich Wilhelm-Johnen-Strasse, 52428 Juelich (Germany); Institut fuer Kristallographie, RWTH Aachen University, D-52066 Aachen (Germany); Albrecht-Schmitt, Thomas E. [Department of Civil Engineering and Geological Sciences, University of Notre Dame, IN 46556 (United States); Department of Chemistry and Biochemistry, University of Notre Dame, IN 46556 (United States); Ewing, Rodney C. [Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005 (United States)

2013-02-15

The hydrothermal treatment of uranium trioxide and methylenediphosphonic acid with a variety of amines (2,2-dipyridyl, triethylenediamine, ethylenediamine, and 1,10-phenanthroline) at 200 Degree-Sign C results in the crystallization of a series of layered uranium diphosphonate compounds, [C{sub 10}H{sub 9}N{sub 2}]{l_brace}UO{sub 2}(H{sub 2}O)[CH{sub 2}(PO{sub 3})(PO{sub 3}H)]{r_brace} (Ubip2), [C{sub 6}H{sub 14}N{sub 2}]{l_brace}(UO{sub 2}){sub 2}[CH{sub 2}(PO{sub 3})(PO{sub 3}H)]{sub 2}{center_dot}2H{sub 2}O{r_brace} (UDAB), [C{sub 2}H{sub 10}N{sub 2}]{sub 2}{l_brace}(UO{sub 2}){sub 2}(H{sub 2}O){sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{sub 2}{center_dot}0.5H{sub 2}O{r_brace} (Uethyl), and [C{sub 12}H{sub 9}N{sub 2}]{l_brace}UO{sub 2}(H{sub 2}O)[CH{sub 2}(PO{sub 3})(PO{sub 3}H)]{r_brace} (Uphen). The crystal structures of the compounds are based on UO{sub 7} units linked by methylenediphosphonate molecules to form two-dimensional anionic sheets in Ubip2 and UDAB, and one-dimensional anionic chains in Uethyl and Uphen, which are charge balanced by protonated amine molecules. Interaction of the amine molecules with phosphonate oxygens and water molecules results in extensive hydrogen bonding in the interlayer. These amine molecules serve both as structure-directing agents and charge-balancing cations for the anionic uranium phosphonate sheets and chains in the formation of the different coordination geometries and topologies of each structure. Reported herein are the syntheses, structural and spectroscopic characterization of the synthesized compounds. - Graphical abstract: The Raman spectra of the synthesized compounds and an illustration of the stacking of the layers with the diprotonated triethylenediamine molecules in [C{sub 6}H{sub 14}N{sub 2}]{l_brace}(UO{sub 2}){sub 2}[CH{sub 2}(PO{sub 3})(PO{sub 3}H)]{sub 2}{center_dot}2H{sub 2}O{r_brace} UDAB. Solvent water molecules are removed for clarity. The corresponding Raman spectra for the complexes synthesized is also

Spectroscopic characteristics of carbon dots (C-dots) derived from carbon fibers and conversion to sulfur-bridged C-dots nanosheets.

Science.gov (United States)

Vinci, John C; Ferrer, Ivonne M; Guterry, Nathan W; Colón, Verónica M; Destino, Joel F; Bright, Frank V; Colón, Luis A

2015-09-01

We synthesized sub-10 nm carbon nanoparticles (CNPs) consistent with photoluminescent carbon dots (C-dots) from carbon fiber starting material. The production of different C-dots fractions was monitored over seven days. During the course of the reaction, one fraction of C-dots species with relatively high photoluminescence was short-lived, emerging during the first hour of reaction but disappearing after one day of reaction. Isolation of this species during the first hour of the reaction was crucial to obtaining higher-luminescent C-dots species. When the reaction proceeded for one week, the appearance of larger nanostructures was observed over time, with lateral dimensions approaching 200 nm. The experimental evidence suggests that these larger species are formed from small C-dot nanoparticles bridged together by sulfur-based moieties between the C-dot edge groups, as if the C-dots polymerized by cross-linking the edge groups through sulfur bridges. Their size can be tailored by controlling the reaction time. Our results highlight the variety of CNP products, from sub-10 nm C-dots to ~200 nm sulfur-containing carbon nanostructures, that can be produced over time during the oxidation reaction of the graphenic starting material. Our work provides a clear understanding of when to stop the oxidation reaction during the top-down production of C-dots to obtain highly photoluminescent species or a target average particle size.

Synthesis, crystal structure and characterization of a 1D polyoxometalate-based compound: {l_brace}[Pr(H{sub 2}O){sub 7}][CrMo{sub 6}H{sub 6}O{sub 24}]{r_brace} . 4H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Zhao Lijie; Shen Shuchang; Yu Haiming [Qiqihar Univ., HL (China). Dept. of Chemistry and Chemical Engineering

2008-07-15

A novel polyoxometalated-based compound, {l_brace}[Pr(H{sub 2}O){sub 7}][CrMo{sub 6}H{sub 6}O{sub 24}]{r_brace} . 4H{sub 2}O, was prepared and characterized by elemental analysis, infrared and ultraviolet spectroscopy, TG measurement and single crystal X-ray diffraction. A chain-like coordination polymer is formed from a heteropolyanion [CrMo{sub 6}H{sub 6}O{sub 24}]{sup 3} as a building unit and [Pr(H{sub 2}O){sub 7}]{sup 3+} cations as linker. The chains are linked into an extensive three-dimensional supramolecular network through hydrogen bonding. The synthesis of 1 is accomplished only from pre-synthesized Anderson clusters, but not from simple starting materials. (orig.)

A new brace treatment similar for adolescent scoliosis and kyphosis based on restoration of thoracolumbar lordosis. Radiological and subjective clinical results after at least one year of treatment

Directory of Open Access Journals (Sweden)

van Loon Piet JM

2012-10-01

Full Text Available Abstract Study design A prospective treatment study with a new brace was conducted Objective. To evaluate radiological and subjective clinical results after one year conservative brace treatment with pressure onto lordosis at the thoracolumbar joint in children with scoliosis and kyphosis. Summary of background data Conservative brace treatment of adolescent scoliosis is not proven to be effective in terms of lasting correction. Conservative treatment in kyphotic deformities may lead to satisfactory correction. None of the brace or casting techniques is based on sagittal forces only applied at the thoracolumbar spine (TLI= thoracolumbar lordotic intervention. Previously we showed in patients with scoliosis after forced lordosis at the thoracolumbar spine a radiological instantaneous reduction in both coronal curves of double major scoliosis. Methods A consecutive series of 91 children with adolescent scoliosis and kyphosis were treated with a modified symmetric 30 degrees Boston brace to ensure only forced lordosis at the thoracolumbar spine. Scoliosis was defined with a Cobb angle of at least one of the curves [greater than or equal to] 25 degrees and kyphosis with or without a curve Results Before treatment start ‘in brace’ radiographs showed a strong reduction of the Cobb angles in different curves in kyphosis and scoliosis groups (sagittal n = 5 all p Conclusion Conservative treatment using thoracolumbar lordotic intervention in scoliotic and kyphotic deformities in adolescence demonstrates a marked improvement after one year also in clinical and postural criteria. An effect not obtained with current brace techniques.

Long-term effects of conservative treatment of Milwaukee brace on body image and mental health of patients with idiopathic scoliosis.

Science.gov (United States)

Misterska, Ewa; Głowacki, Jakub; Głowacki, Maciej; Okręt, Adam

2018-01-01

We aimed to provide a complex assessment of adult females with adolescent idiopathic scoliosis (AIS) after a minimum of 23 years after completed Milwaukee brace treatment. In the present study, a comparison between healthy female and AIS patients' perception of trunk disfigurement, self-image, mental health, pain level and everyday activity was made. Thirty AIS patients with a mean of 27.77 yrs (SD 3.30) after the treatment were included in the study. The control group consisted of 42 females, matching the age profile of the patient group. Study participants from both groups were examined using the same protocol, except for the radiological evaluation. Patients and healthy controls completed the Polish versions of the Scoliosis Research Society (SRS-22) and Spinal Appearance Questionnaire (SAQ). Patients additionally filled the Bad Sobberheim Stress Questionnaire-Deformity (BSSQ-Deformity) and Bad Sobberheim Stress Questionnaire-Brace (BSSQ-Brace). The study group's SAQ results differ significantly in regard to the total score and all individual domains, indicating better functioning among healthy controls. Except for the General domain (p = 0.002), among the remaining subscales the study group's results differed significantly at p<0.001. Considering SRS-22 results, it was revealed that the patient group scored higher, signaling better functioning with reference to pain level (p = 0.016), function/activity (p<0.001) and the total score (p<0.001). The findings add to the complexity of long-term effect evaluations of AIS, particularly amongst females treated with a Milwaukee brace. Long-term results were not conclusive in terms of nonverbal assessment of body image and emotional tension regarding the experiences of brace-wearing. Future patients can be reassured that scoliosis treated conservatively does not negatively affect everyday activity, pain level, childbearing and mental health. Subjects who declared to have psychological problems due to scoliosis had a

Long-term effects of conservative treatment of Milwaukee brace on body image and mental health of patients with idiopathic scoliosis.

Directory of Open Access Journals (Sweden)

Ewa Misterska

Full Text Available We aimed to provide a complex assessment of adult females with adolescent idiopathic scoliosis (AIS after a minimum of 23 years after completed Milwaukee brace treatment. In the present study, a comparison between healthy female and AIS patients' perception of trunk disfigurement, self-image, mental health, pain level and everyday activity was made. Thirty AIS patients with a mean of 27.77 yrs (SD 3.30 after the treatment were included in the study. The control group consisted of 42 females, matching the age profile of the patient group. Study participants from both groups were examined using the same protocol, except for the radiological evaluation. Patients and healthy controls completed the Polish versions of the Scoliosis Research Society (SRS-22 and Spinal Appearance Questionnaire (SAQ. Patients additionally filled the Bad Sobberheim Stress Questionnaire-Deformity (BSSQ-Deformity and Bad Sobberheim Stress Questionnaire-Brace (BSSQ-Brace. The study group's SAQ results differ significantly in regard to the total score and all individual domains, indicating better functioning among healthy controls. Except for the General domain (p = 0.002, among the remaining subscales the study group's results differed significantly at p<0.001. Considering SRS-22 results, it was revealed that the patient group scored higher, signaling better functioning with reference to pain level (p = 0.016, function/activity (p<0.001 and the total score (p<0.001. The findings add to the complexity of long-term effect evaluations of AIS, particularly amongst females treated with a Milwaukee brace. Long-term results were not conclusive in terms of nonverbal assessment of body image and emotional tension regarding the experiences of brace-wearing. Future patients can be reassured that scoliosis treated conservatively does not negatively affect everyday activity, pain level, childbearing and mental health. Subjects who declared to have psychological problems due to scoliosis

Influence of the Soil-Structure Interaction on the Design of Steel-Braced Building Foundation

International Nuclear Information System (INIS)

Azarbakht, Alireza; Ashtiany, Mohsen Ghafory

2008-01-01

The modeling and analysis of the superstructure and the foundation for the seismic lateral loads are traditionally done separately. This assumption is an important issue in the design/rehabilitate procedures especially for the short period structures, i.e. steel braced or shear wall systems, which may result to a conservative design. By using more advance procedures, i.e. nonlinear static method, and the incorporation of the soil-structure interaction (SSI), the seismic demand in the lateral resisting system decreases and the design will become more economic. This paper includes an investigation about the influence of the SSI effect on the design of the steel-braced building foundation. The presented example is a three-bay three-storey steel braced frame. Three design methods based on the FEMA 356 guideline and the UBC 97 code are taken in to consideration. The three methods are: (1) linear static analysis based on the UBC 97 code assuming the fixed based condition; (2) linear static analysis based on the FEMA 356 guideline assuming the fixed based condition; and (3) nonlinear static analysis assuming both fixed and flexible based assumptions. The results show that the influence of the SSI on the input demand of the short period building foundations is significant and the foundation design based on the linear static method with the fixed base assumption is so conservative. A simple method is proposed to take the SSI effect in to consideration in the linear static procedure with the fixed base assumption, which is a common method for the engineers. The advantage of this proposed method is the simplicity and the applicability for the engineering purposes

A radial holding device for the bundle and brace plates envelope in a vapor generator, by the means of enclosed screw stops

International Nuclear Information System (INIS)

Comic, G.

1995-01-01

With the aim to protect the envelopes and bundles against seisms or other constraints, without causing interference with the water flow or being too complicated to install, as with previous systems, a holding system is proposed which uses screw stops fixed to the envelope and to the brace; the screw, enclosed in one of the two parts, ensures, during the assembly, the displacement of the second part for good contact with the brace plate. 6 fig

Expecting ankle tilts and wearing an ankle brace influence joint control in an imitated ankle sprain mechanism during walking.

Science.gov (United States)

Gehring, Dominic; Wissler, Sabrina; Lohrer, Heinz; Nauck, Tanja; Gollhofer, Albert

2014-03-01

A thorough understanding of the functional aspects of ankle joint control is essential to developing effective injury prevention. It is of special interest to understand how neuromuscular control mechanisms and mechanical constraints stabilize the ankle joint. Therefore, the aim of the present study was to determine how expecting ankle tilts and the application of an ankle brace influence ankle joint control when imitating the ankle sprain mechanism during walking. Ankle kinematics and muscle activity were assessed in 17 healthy men. During gait rapid perturbations were applied using a trapdoor (tilting with 24° inversion and 15° plantarflexion). The subjects either knew that a perturbation would definitely occur (expected tilts) or there was only the possibility that a perturbation would occur (potential tilts). Both conditions were conducted with and without a semi-rigid ankle brace. Expecting perturbations led to an increased ankle eversion at foot contact, which was mediated by an altered muscle preactivation pattern. Moreover, the maximal inversion angle (-7%) and velocity (-4%), as well as the reactive muscle response were significantly reduced when the perturbation was expected. While wearing an ankle brace did not influence muscle preactivation nor the ankle kinematics before ground contact, it significantly reduced the maximal ankle inversion angle (-14%) and velocity (-11%) as well as reactive neuromuscular responses. The present findings reveal that expecting ankle inversion modifies neuromuscular joint control prior to landing. Although such motor control strategies are weaker in their magnitude compared with braces, they seem to assist ankle joint stabilization in a close-to-injury situation. Copyright © 2013 Elsevier B.V. All rights reserved.

An investigation on the effect of gusset plate connection rigidity on the seismic behavior of special concentrically braced frames

Directory of Open Access Journals (Sweden)

Ali Esnaashari

2016-12-01

Full Text Available Special concentrically braced frames (SCBFs are commonly used to resist lateral loads in buildings. The bracing system sustains large deformations due to inelastic behavior in bracing members (buckling and yielding in tension. Generally, in the conventional modeling strategy, the effect of gusset plates in providing beam-column connections rigidity and hence, improving the post-buckling performance of these frames is not taken into account. This paper deals with the effect of gusset plate rigidity on the seismic behavior of SCBFs using Roeder’s proposed model in the literature. In this paper, four 3, 6, 9 and 12-story SCBFs were designed and modeled using two distinct methods: conventional method with hinged connections and Roeder’s method with semi-rigid connections. Then, the models behavior was investigated with both pushover analysis and nonlinear time-history analysis using OpenSees software. The results showed that lateral load capacity of the frames modeled with the Roeder’s proposed model are about 10% larger than the conventional method’s capacity. Also, it was found that the semi-rigid model leads to a less drift ratios and more overstrength factors.

The effect of knee brace and knee sleeve on the proprioception of the knee in young non-professional healthy sportsmen.

Science.gov (United States)

Bottoni, G; Herten, A; Kofler, P; Hasler, M; Nachbauer, W

2013-12-01

Proprioception has been defined as the capacity to feel the position of a joint in space as sensed by the central nervous system. Prophylactic knee braces are supposed to help in knee injury prevention not just with a mechanical support of the joint but also improving proprioception. The main aim of this study was to determine the effects of a knee brace and a knee sleeve on knee proprioception. The secondary aim was to determine if different starting angles of the knee and different movement directions influence knee proprioception. We tested a group of twenty healthy male sport students without knee injuries. They were tested with the brace, with the sleeve and without support. The threshold of detection of passive knee movement with a starting knee angle of 30° and 60°, both in flexion and extension was determined. We did not find any statistically significant change in the threshold of detection of passive knee movement wearing the brace or the sleeve compared to the unsupported condition (p=0.462, α=0.05). We found a significantly lower proprioceptive sensitivity starting at the more flexed knee angle (p=0.005, α=0.05) and moving in extension than in the other test situations (p=0.001, α=0.05). Movement direction and starting position appear to influence the threshold of detection of passive knee movement. The results of this study also suggest that knee supports do not influence either positively or negatively knee proprioception of uninjured active subjects. Copyright © 2013 Elsevier B.V. All rights reserved.

Energies and wave functions of an off-centre donor in hemispherical quantum dot: Two-dimensional finite difference approach and ritz variational principle

Energy Technology Data Exchange (ETDEWEB)

Nakra Mohajer, Soukaina; El Harouny, El Hassan [Laboratoire de Physique de la Matière Condensée, Département de Physique, Faculté des Sciences, Université Abdelmalek Essaadi, B.P. 2121 M’Hannech II, 93030 Tétouan (Morocco); Ibral, Asmaa [Equipe d’Optique et Electronique du Solide, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B. P. 20 El Jadida Principale, El Jadida (Morocco); Laboratoire d’Instrumentation, Mesure et Contrôle, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B. P. 20 El Jadida Principale, El Jadida (Morocco); El Khamkhami, Jamal [Laboratoire de Physique de la Matière Condensée, Département de Physique, Faculté des Sciences, Université Abdelmalek Essaadi, B.P. 2121 M’Hannech II, 93030 Tétouan (Morocco); and others

2016-09-15

Eigenvalues equation solutions of a hydrogen-like donor impurity, confined in a hemispherical quantum dot deposited on a wetting layer and capped by an insulating matrix, are determined in the framework of the effective mass approximation. Conduction band alignments at interfaces between quantum dot and surrounding materials are described by infinite height barriers. Ground and excited states energies and wave functions are determined analytically and via one-dimensional finite difference approach in case of an on-center donor. Donor impurity is then moved from center to pole of hemispherical quantum dot and eigenvalues equation is solved via Ritz variational principle, using a trial wave function where Coulomb attraction between electron and ionized donor is taken into account, and by two-dimensional finite difference approach. Numerical codes developed enable access to variations of donor total energy, binding energy, Coulomb correlation parameter, spatial extension and radial probability density with respect to hemisphere radius and impurity position inside the quantum dot.

Energies and wave functions of an off-centre donor in hemispherical quantum dot: Two-dimensional finite difference approach and ritz variational principle

International Nuclear Information System (INIS)

Nakra Mohajer, Soukaina; El Harouny, El Hassan; Ibral, Asmaa; El Khamkhami, Jamal

2016-01-01

Eigenvalues equation solutions of a hydrogen-like donor impurity, confined in a hemispherical quantum dot deposited on a wetting layer and capped by an insulating matrix, are determined in the framework of the effective mass approximation. Conduction band alignments at interfaces between quantum dot and surrounding materials are described by infinite height barriers. Ground and excited states energies and wave functions are determined analytically and via one-dimensional finite difference approach in case of an on-center donor. Donor impurity is then moved from center to pole of hemispherical quantum dot and eigenvalues equation is solved via Ritz variational principle, using a trial wave function where Coulomb attraction between electron and ionized donor is taken into account, and by two-dimensional finite difference approach. Numerical codes developed enable access to variations of donor total energy, binding energy, Coulomb correlation parameter, spatial extension and radial probability density with respect to hemisphere radius and impurity position inside the quantum dot.

The classical and a modified Boston brace: description and results.

Science.gov (United States)

Grivas, Theodoros B; Kaspiris, Angelos

2011-01-01

Idiopathic scoliosis (IS) is characterized by the lateral deviation of the spine and constitutes a three-dimensional distortion that leads to geometric and morphological lesions in the spine and thoracic cage. The most widespread method of conservative management is to use spinal orthoses or body braces. These are usually recommended in patients with skeletal immaturity with a Risser sign 2 or less and with curves ranging from 25° to 45°. Of these, perhaps one of the most popular in recent years is the Boston Brace. It was developed in the early 1970s, and its design is based on symmetry, consisting of extensions and pads, with each of them exerting corrective forces and has a specific role depending on the type of scoliosis. It is important that the treatment group, the patient, and the family environment should work as a team consistently and be well trained to achieve the best result. Various studies published in international literature have observed beneficial effects from the use of the Boston system. Nevertheless, there are still issues that need further investigation regarding its effectiveness depending on the type of curves, the duration of application, the gender, and BMI of patients to whom it is applied. However, without question, if all these factors are taken into account and with the compliance of the therapy group with the instructions, the main goal can be achieved, which is the stability of the spine, and the ultimate result of clinical-radiological and aesthetic improvement, which is directly linked to the psychological satisfaction of the patient.

Study of InGaN/GaN quantum dot systems by TEM techniques and photoluminescence spectroscopy

International Nuclear Information System (INIS)

Kashtiban, R J; Bangert, U; Harvey, A J; Sherliker, B; Halsall, M P

2010-01-01

InGaN/GaN multilayer quantum dot structures produced by MOCVD techniques on c-plane sapphire were studied by transmission electron microscopy (TEM) and photoluminescence (PL) techniques. Indium fluctuations ranging from 1-4 nm were observed with both energy filtered TEM (EFTEM) and high angle annular dark field (HAADF) scanning TEM. The existence of V-shaped defects with nucleation centres at the termination of threading dislocation were observed in HAADF images. There was also evidence of the formation of large quantum dots at low densities from lattice HRTEM images. This was further confirmed by PL measurements through the observation of a single sharp line at low power with the typical saturation behaviour at higher power excitation.

Is the effectiveness of patellofemoral bracing modified by patellofemoral alignment and trochlear morphology?

Science.gov (United States)

Zhang, Xi; Eyles, Jillian P; Makovey, Joanna; Williams, Matthew J; Hunter, David J

2017-04-21

This study was performed to determine if the effectiveness of patellofemoral bracing as a treatment for patellofemoral osteoarthritis is influenced by patellofemoral joint alignment and trochlear morphology. We hypothesized that those with more extreme patellar malalignment would benefit more from bracing. Thirty-eight patients who had received bracing as part of a comprehensive treatment plan for patellofemoral osteoarthritis were selected for this study. Ten measures of patellar alignment were taken from X-rays. These alignment measures were divided into percentile groups (tertiles) for contingency table analysis. Treatment outcome was measured by Western Ontario and Macmasters Universities Osteoarthritis Index (WOMAC) scores and these were dichotomised into two groups according to "Improved" or "Not Improved" according to the minimum clinically important difference (MCID). Spearman's rho test was performed for continuous variables and Fisher's exact test was performed for correlation between tertile groups and MCID categories. Thirty-eight patients (9 male and 29 female) between the ages of 51 to 89 were included in this study. WOMAC scores ranged from -25 to 41.67, with a mean change of -3.97, 31.6, 44.7 and 31.6% of patients falling into the "Improved" group for Global, Pain and Function scores respectively. We found a non-significant trend shown (p = 0.058, correlation coefficient 0.31) between bisect offset and change in WOMAC global, indicating a trend for higher change in WOMAC scores with increasing bisect offset. Statistically significant correlations were found between mean MCID categories for the WOMAC global and function groups when analysed against percentile groups for bisect offset (p < 0.01) and patellar subluxation distance (p < 0.05), indicating those in higher percentile groups were more likely not to improve after six months. Higher bisect offset and patellar subluxation distance measures were associated with poorer outcomes

Combining valgus knee brace and lateral foot wedges reduces external forces and moments in osteoarthritis patients

NARCIS (Netherlands)

Jafarnezhadgero, Amir Ali; Oliveira, Anderson S.; Mousavi, Seyed Hamed; Madadi-Shad, Morteza

Osteoarthritis progression can be related to the external knee adduction and flexion moments during walking. Lateral foot wedges and knee braces have been used as treatment for osteoarthritis, but little is known about their influence on knee joint moments generated in the sagittal and frontal

Aging effect in CaLaBa{l_brace}Cu{sub 1 - x}Fe{sub x}{r_brace}{sub 3}O{sub 7 - {delta}} with 0 {<=} x {<=} 0.07 studied by Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bustamante, Angel, E-mail: angelbd1@gmail.com [Universidad Nacional Mayor de San Marcos, Laboratorio de Ceramicos y Nanomateriales, Facultad de Ciencias Fisicas (Peru); Santos Valladares, Luis De Los, E-mail: ld301@cam.ac.uk [University of Cambridge, Cavendish Laboratory (United Kingdom); Flores, Jesus [Universidad Nacional Mayor de San Marcos, Laboratorio de Ceramicos y Nanomateriales, Facultad de Ciencias Fisicas (Peru); Barnes, Crispin H. W. [University of Cambridge, Cavendish Laboratory (United Kingdom); Majima, Yutaka [Tokyo Institute of Technology, Materials and Structures Laboratory (Japan)

2011-11-15

In this work, we study the long-term aging effect caused by Fe atoms in the superconductor CaLaBa{l_brace}Cu{sub 1 - x}Fe{sub x}{r_brace}{sub 3}O{sub 7 - {delta}} with 0 {<=} x {<=} 0.07. XRD confirms that this system has a YBCO-like structure. The critical temperature (T{sub c}) is strongly affected by aging and depends on the amount of Fe in the structure. Room temperature Moessbauer spectroscopy reveals the presence of the typical species A, B-B Prime , C and new species E Prime and F. Interestingly; A, which corresponds to the Fe{sup 3 + } atom located in the Cu(1) of the chains with spin S{sub z} = 3/2, shows a drastic reduction which means migration to the species B, B Prime and C. Species B and B Prime correspond to the Fe{sup 3 + } in the Cu(2) site forming planar quasi-octahedral and planar square pyramidal, while the C specie is a square pyramidal with O(5) respectively (spin S{sub z} = 3/2 in all these cases). Aging causes loss of superconductivity in the samples with 5 and 7% of iron content.

DOT for patients with limited access to health care facilities in a hill district of eastern Nepal.

Science.gov (United States)

Wares, D F; Akhtar, M; Singh, S

2001-08-01

The hill district in Nepal, where access to health care facilities is difficult. To compare results before and after a decentralised directly observed treatment (DOT) intervention. Prospective study of patients registered in Dhankuta district, Nepal, 1996-1999. Patients received their intensive phase treatment under health worker supervision via one of three DOT options: 1) ambulatory from the peripheral government health facilities; 2) ambulatory from an international non-governmental organisation (INGO) TB clinic in district centre; or 3) resident in INGO TB hostel in district centre. Historical data from 1995-1996, with unsupervised short-course chemotherapy, were used for comparison. Of 307 new cases, respectively 126 (41%), 86 (28%) and 95 (31%) took their intensive phase treatment via options 1, 2 and 3. Smear conversion (at 2 months) and cure rates in new smear-positive pulmonary tuberculosis cases were respectively 81.6% (vs. 58.8% historical, P = 0.001) and 84.9% (vs. 76.7% historical, P = 0.03). Overall costs to the INGO provider fell by 7%, mainly as a result of staffing reductions in the INGO services made possible by rationalisation with government services during the intervention. By offering varied DOT delivery routes, including an in-patient option, satisfactory results are possible with DOT even in areas where access to health care facilities is difficult. Provision of in-patient care via an INGO TB hostel allowed a significant proportion of new cases (31%) to receive their intensive phase treatment who otherwise may have had difficulty accessing treatment, due either to the distance to the nearest health facility or to disease severity. Substitution of government hospital beds or local hotel beds for the INGO hostel beds may allow the model to be reproduced elsewhere in similar geographical conditions in Nepal, but further studies should be performed in a non-INGO supported district beforehand.

Transport in quantum dots

International Nuclear Information System (INIS)

Deus, Fernanda; Continetino, Mucio

2011-01-01

Full text. In this work we study the time dependent transport in interacting quantum dot. This is a zero-dimensional nano structure system which has quantized electronic states. In our purpose, we are interested in studying such system in a Coulomb blockade regime where a mean-field treatment of the electronic correlations are appropriate. The quantum dot is described by an Anderson type of Hamiltonian where the hybridization term arises from the contact with the leads. We consider a time dependence of both the energy of the localized state in the quantum dot and of the hybridization-like term. These time dependent parameters, under certain conditions, induce a current in the quantum dot even in the absence of difference on the chemical potential of the leads. The approach to this non-equilibrium problem requires the use of a Keldysh formalism. We calculate the non- equilibrium Green's functions and obtain results for the average (equilibrium term) and the non-equilibrium values of the electronic occupation number in the dot. we consider the possibility of a magnetic solution, with different values for the average up and down spins in the quantum dot. Our results allow to obtain, for instance, the tunneling current through the dot. The magnetic nature of the dot, for a certain range of parameters should give rise also to an induced spin current through the dot

Modeling of the quantum dot filling and the dark current of quantum dot infrared photodetectors

International Nuclear Information System (INIS)

Ameen, Tarek A.; El-Batawy, Yasser M.; Abouelsaood, A. A.

2014-01-01

A generalized drift-diffusion model for the calculation of both the quantum dot filling profile and the dark current of quantum dot infrared photodetectors is proposed. The confined electrons inside the quantum dots produce a space-charge potential barrier between the two contacts, which controls the quantum dot filling and limits the dark current in the device. The results of the model reasonably agree with a published experimental work. It is found that increasing either the doping level or the temperature results in an exponential increase of the dark current. The quantum dot filling turns out to be nonuniform, with a dot near the contacts containing more electrons than one in the middle of the device where the dot occupation approximately equals the number of doping atoms per dot, which means that quantum dots away from contacts will be nearly unoccupied if the active region is undoped

Costs and cost-effectiveness of different DOT strategies for the treatment of tuberculosis in Pakistan. Directly Observed Treatment.

Science.gov (United States)

Khan, M A; Walley, J D; Witter, S N; Imran, A; Safdar, N

2002-06-01

An economic study was conducted alongside a clinical trial at three sites in Pakistan to establish the costs and effectiveness of different strategies for implementing directly observed treatment (DOT) for tuberculosis. Patients were randomly allocated to one of three arms: DOTS with direct observation by health workers (at health centres or by community health workers); DOTS with direct observation by family members; and DOTS without direct observation. The clinical trial found no statistically significant difference in cure rate for the different arms. The economic study collected data on the full range of health service costs and patient costs of the different treatment arms. Data were also disaggregated by gender, rural and urban patients, by treatment site and by economic categories, to investigate the costs of the different strategies, their cost-effectiveness and the impact that they might have on patient compliance with treatment. The study found that direct observation by health centre-based health workers was the least cost-effective of the strategies tested (US dollars 310 per case cured). This is an interesting result, as this is the model recommended by the World Health Organization and International Union against Tuberculosis and Lung Disease. Attending health centres daily during the first 2 months generated high patient costs (direct and in terms of time lost), yet cure rates for this group fell below those of the non-observed group (58%, compared with 62%). One factor suggested by this study is that the high costs of attending may be deterring patients, and in particular, economically active patients who have most to lose from the time taken by direct observation. Without stronger evidence of benefits, it is hard to justify the costs to health services and patients that this type of direct observation imposes. The self-administered group came out as most cost-effective (164 dollars per case cured). The community health worker sub-group achieved the

Reliability assessment of serviceability performance of braced retaining walls using a neural network approach

Science.gov (United States)

Goh, A. T. C.; Kulhawy, F. H.

2005-05-01

In urban environments, one major concern with deep excavations in soft clay is the potentially large ground deformations in and around the excavation. Excessive movements can damage adjacent buildings and utilities. There are many uncertainties associated with the calculation of the ultimate or serviceability performance of a braced excavation system. These include the variabilities of the loadings, geotechnical soil properties, and engineering and geometrical properties of the wall. A risk-based approach to serviceability performance failure is necessary to incorporate systematically the uncertainties associated with the various design parameters. This paper demonstrates the use of an integrated neural network-reliability method to assess the risk of serviceability failure through the calculation of the reliability index. By first performing a series of parametric studies using the finite element method and then approximating the non-linear limit state surface (the boundary separating the safe and failure domains) through a neural network model, the reliability index can be determined with the aid of a spreadsheet. Two illustrative examples are presented to show how the serviceability performance for braced excavation problems can be assessed using the reliability index.

Ankles back in randomized controlled trial (ABrCt): braces versus neuromuscular exercises for the secondary prevention of ankle sprains. Design of a randomised controlled trial.

Science.gov (United States)

Janssen, Kasper W; van Mechelen, Willem; Verhagen, Evert Alm

2011-09-27

Ankle sprains are the most common sports and physical activity related injury. There is extensive evidence that there is a twofold increased risk for injury recurrence for at least one year post injury. In up to 50% of all cases recurrences result in disability and lead to chronic pain or instability, requiring prolonged medical care. Therefore ankle sprain recurrence prevention in athletes is essential. This RCT evaluates the effect of the combined use of braces and neuromuscular training (e.g. proprioceptive training/sensorimotor training/balance training) against the individual use of either braces or neuromuscular training alone on ankle sprain recurrences, when applied to individual athletes after usual care. This study was designed as three way randomized controlled trial with one year follow-up. Healthy individuals between 12 and 70 years of age, who were actively participating in sports and who had sustained a lateral ankle sprain in the two months prior to inclusion, were eligible for inclusion. After subjects had finished ankle sprain treatment by means of usual care, they were randomised to any of the three study groups. Subjects in group 1 received an eight week neuromuscular training program, subjects in group 2 received a sports brace to be worn during all sports activities for the duration of one year, and group 3 received a combination of the neuromuscular training program and a sports brace to be worn during all sports activities for the duration of eight weeks. Outcomes were assessed at baseline and every month for 12 months therafter. The primary outcome measure was incidence of ankle sprain recurrences. Secondary outcome measures included the direct and indirect costs of recurrent injury, the severity of recurrent injury, and the residual complaints during and after the intervention. The ABrCt is the first randomized controlled trial to directly compare the secondary preventive effect of the combined use of braces and neuromuscular training

Improving the seismic performance of eccentrically braced frames by using a ductile element

OpenAIRE

Morteza Naghipour; Seyed Reza Salim Bahrami

2017-01-01

Stability of structures against earthquake is much important to prevent total or partial failure of structures and loss of financial and human investments of people and country. Eccentrically braced frames, as one of the most commonly used earthquake resistant systems, with good ductility and toughness, have different arrangements; one of them is Link beam-to-column connection. This type of connection was considered as bending form before the North Ridge earthquake (1994). But conducted resea...

DOT's CAFE rulemaking analysis.

Science.gov (United States)

2013-02-13

Presentation discusses what DOT needs to consider in setting CAFE standards. How DOT's use of the CAFE Compliance and Effects Modeling System helps to analyze potential CAFE Standards. How DOT might approach the next round of CAFE standards for model...

Inversion of spin levels in Ni sup 2 sup + : Zn(BF sub 4) sub 2 centre dot 6H sub 2 O at all -round compression and effect of transition coincidence

CERN Document Server

Krygin, I M; Nejlo, G N; Prokhorov, A D

2001-01-01

The study of the EPR spectrum of the Ni sup 2 sup + ion, replacing Zn sup 2 sup + in the Zn(BF sub 4) centre dot 6H sub 2 O crystals in the wide temperature range by the all-round compression in the X- and Q-ranges is carried out. The basic changes by varying temperature and pressure occur with the D parameter, characterizing the initial splitting by practically unchanged g-factor. The increase in the temperature is accompanied by the D nonlinear growth. The all-round compression linearly changes the initial splitting and leads to the change in the D-sign, signifying the spin levels inversion by 3.5 kbar. Coincidence of EPR lines, relative to different transitions, leads to the crevasse appearance in the outline of this one, that is connected with cross-relaxation inside the spin system

Short-wavelength InAlGaAs/AlGaAs quantum dot superluminescent diodes

Science.gov (United States)

Liang, De-Chun; An, Qi; Jin, Peng; Li, Xin-Kun; Wei, Heng; Wu, Ju; Wang, Zhan-Guo

2011-10-01

This paper reports the fabrication of J-shaped bent-waveguide superluminescent diodes utilizing an InAlGaAs/AlGaAs quantum dot active region. The emission spectrum of the device is centred at 884 nm with a full width at half maximum of 37 nm and an output power of 18 mW. By incorporating an Al composition into the quantum dot active region, short-wavelength superluminescent diode devices can be obtained. An intersection was found for the light power-injection current curves measured from the straight-waveguide facet and the bent-waveguide facet, respectively. The result is attributed to the conjunct effects of the gain and the additional loss of the bent waveguide. A numerical simulation is performed to verify the qualitative explanation. It is shown that bent waveguide loss is an important factor that affects the output power of J-shaped superluminescent diode devices.

Strength and Functional Improvement Using Pneumatic Brace with Extension Assist for End-Stage Knee Osteoarthritis: A Prospective, Randomized trial.

Science.gov (United States)

Cherian, Jeffrey J; Bhave, Anil; Kapadia, Bhaveen H; Starr, Roland; McElroy, Mark J; Mont, Michael A

2015-05-01

Pneumatic unloader bracing with extension assists have been proposed as a non-operative modality that may delay the need for knee surgery by reducing pain and improving function. This prospective, randomized trial evaluated 52 patients who had knee osteoarthritis for changes in: (1) muscle strength; (2) objective functional improvements; (3); subjective functional improvements; (4) pain; (5) quality of life; and (6) conversion to total knee arthroplasty (TKA) compared to standard of care. Patient outcomes were evaluated at a minimum 3 months. Braced patient's demonstrated significant improvements in muscle strength, several functional tests, and patient reported outcomes when compared to the matched cohort. These results are encouraging and suggest that this device may represent a promising alternative to standard treatment methods for knee osteoarthritis. Copyright © 2014 Elsevier Inc. All rights reserved.

Phonon impact on optical control schemes of quantum dots: Role of quantum dot geometry and symmetry

Science.gov (United States)

Lüker, S.; Kuhn, T.; Reiter, D. E.

2017-12-01

Phonons strongly influence the optical control of semiconductor quantum dots. When modeling the electron-phonon interaction in several theoretical approaches, the quantum dot geometry is approximated by a spherical structure, though typical self-assembled quantum dots are strongly lens-shaped. By explicitly comparing simulations of a spherical and a lens-shaped dot using a well-established correlation expansion approach, we show that, indeed, lens-shaped dots can be exactly mapped to a spherical geometry when studying the phonon influence on the electronic system. We also give a recipe to reproduce spectral densities from more involved dots by rather simple spherical models. On the other hand, breaking the spherical symmetry has a pronounced impact on the spatiotemporal properties of the phonon dynamics. As an example we show that for a lens-shaped quantum dot, the phonon emission is strongly concentrated along the direction of the smallest axis of the dot, which is important for the use of phonons for the communication between different dots.

The effect of taping versus semi-rigid bracing on patient outcome and satisfaction in ankle sprains: a prospective, randomized controlled trial

Directory of Open Access Journals (Sweden)

Lardenoye Sacha

2012-05-01

Full Text Available Abstract Background Functional treatment is a widely used and generally accepted treatment for ankle sprain. A meta-analysis comparing the different functional treatment options could not make definitive conclusions regarding the effectiveness, and until now, little was known about patient satisfaction in relation to the outcome. Methods Patients with acute ankle sprain received rest, ice, compression and elevation with an compressive bandage at the emergency department. After 5-7 days, 100 patients with grade II and III sprains were randomized into two groups: one group was treated with tape and the other with a semi-rigid ankle brace, both for 4 weeks. Post-injury physical and proprioceptive training was standardized. As primary outcome parameter patient satisfaction and skin complications were evaluated using a predefined questionnaire and numeric rating scale. As secondary outcome parameter the ankle joint function was assessed using the Karlsson scoring scale and range of motion. Results Patient-reported comfort and satisfaction during treatment with a semi-rigid brace was significantly increased. The rate of skin complication in this group was significantly lower compared to the tape group (14.6% versus 59.1%, P  Conclusion Treatment of acute ankle sprain with semi-rigid brace leads to significantly higher patient comfort and satisfaction, both with similar good outcome.

Five new Zn(II) and Cd(II) coordination polymers constructed by 3,5-bis-oxyacetate-benzoic acid: Syntheses, crystal structures, network topologies and luminescent properties

Energy Technology Data Exchange (ETDEWEB)

Jiang Xianrong; Yuan Hongyan [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Feng Yunlong, E-mail: sky37@zjnu.edu.cn [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China)

2012-07-15

Five Zn(II) and Cd(II) coordination polymers, [Zn{sub 2}(BOABA)(bpp)(OH)]{center_dot}0.5H{sub 2}O (1), [Cd{sub 3}(BOABA){sub 2}(bpp){sub 2}(H{sub 2}O){sub 6}]{center_dot}2H{sub 2}O (2), [Cd{sub 3}(BOABA){sub 2}(2,2 Prime -bipy){sub 3}(H{sub 2}O){sub 4}]{center_dot}5.5H{sub 2}O (3), [CdNa(BOABA)(H{sub 2}O)]{sub 2}{center_dot}H{sub 2}O (4) and [Cd{sub 2}(BOABA)(bimb)Cl(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O (5) (H{sub 3}BOABA=3,5-bis-oxyacetate-benzoic acid, bpp=1,3-bi(4-pyridyl)propane, 2,2 Prime -bipy=2,2 Prime -bipyridine, bimb=1,4-bis(imidazol-1 Prime -yl)butane), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and TG analyses. 1 is an uninodal 4-connected 2D square grid network based on binuclear zinc clusters. 2 is 2D wavelike layer structure and further linked by hydrogen bonds into the final 3D (5,6,6)-connected topology network. 3 is 3-connected 2D topology network and the 2,2 Prime -bipy ligands decorate in two different types. 4 is a (4,8)-connected 2D topology network with heterocaryotic {l_brace}Cd{sub 2}Na{sub 2}{r_brace} clusters and BOABA{sup 3-} ligands. 5 can be rationalized as a (3,10)-connected 3D topology network with tetranuclear {l_brace}Cd{sub 4}Cl{sub 2}{r_brace} clusters and BOABA{sup 3-} ligands. Meanwhile, photoluminescence studies revealed that these five coordination polymers display strong fluorescent emission bands in the solid state at room temperature. - Graphical abstract: Five new d{sup 10} metal(II) coordination polymers based on H{sub 3}BOABA ligand were obtained and characterized. They display different topological structures and luminescent properties. Highlights: Black-Right-Pointing-Pointer Five d{sup 10} metal(II) polymers based on 3,5-bis-oxyacetate-benzoic acid were obtained. Black-Right-Pointing-Pointer The polymers were structurally characterized by single-crystal X-ray diffraction. Black-Right-Pointing-Pointer Polymers 1-5 display different

A series of 2D metal-quinolone complexes: Syntheses, structures, and physical properties

Energy Technology Data Exchange (ETDEWEB)

He, Jiang-Hong [College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Xiao, Dong-Rong, E-mail: xiaodr98@yahoo.com.cn [College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Chen, Hai-Yan; Sun, Dian-Zhen; Yan, Shi-Wei; Wang, Xin; Ye, Zhong-Li [College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Luo, Qun-Li, E-mail: qlluo@swu.edu.cn [College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Wang, En-Bo, E-mail: wangeb889@nenu.edu.cn [Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun 130024 (China)

2013-02-15

Six novel 2D metal-quinolone complexes, namely [Cd(cfH)(bpdc)]{center_dot}H{sub 2}O (1), [M(norfH)(bpdc)]{center_dot}H{sub 2}O (M=Cd (2) and Mn (3)), [Mn{sub 2}(cfH)(odpa)(H{sub 2}O){sub 3}]{center_dot}0.5H{sub 2}O (4), [Co{sub 2}(norfH)(bpta)({mu}{sub 2}-H{sub 2}O)(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O (5) and [Co{sub 3}(saraH){sub 2}(Hbpta){sub 2}(H{sub 2}O){sub 4}]{center_dot}9H{sub 2}O (6) (cfH=ciprofloxacin, norfH=norfloxacin, saraH=sarafloxacin, bpdc=4,4 Prime -biphenyldicarboxylate, odpa=4,4 Prime -oxydiphthalate, bpta=3,3 Prime ,4,4 Prime -biphenyltetracarboxylate) have been synthesized and characterized. Compounds 1-3 consist of 2D arm-shaped layers based on the 1D {l_brace}M(COO){r_brace}{sub n}{sup n+} chains. Compounds 4 and 5 display 2D structures based on tetranuclear manganese or cobalt clusters with (3,6)-connected kgd topology. Compound 6 exhibits a 2D bilayer structure, which represents the first example of metal-quinolone complexes with 2D bilayer structure. By inspection of the structures of 1-6, it is believed that the long aromatic polycarboxylate ligands are important for the formation of 2D metal-quinolone complexes. The magnetic properties of compounds 3-6 was studied, indicating the existence of antiferromagnetic interactions. Furthermore, the luminescent properties of compounds 1-2 are discussed. - Graphical abstract: Six novel 2D metal-quinolone complexes have been prepared by self-assemblies of the quinolones and metal salts in the presence of long aromatic polycarboxylates. Highlights: Black-Right-Pointing-Pointer Compounds 1-3 consist of novel 2D arm-shaped layers based on the 1D {l_brace}M(COO){r_brace}{sub n}{sup n+} chains. Black-Right-Pointing-Pointer Compounds 4 and 5 are two novel 2D layers based on tetranuclear Mn or Co clusters with kgd topology. Black-Right-Pointing-Pointer Compound 6 is the first example of metal-quinolone complexes with 2D bilayer structure. Black-Right-Pointing-Pointer Compounds 1-6 represent six unusual

Treatment of thoraco-lumbar curves in adolescent females affected by idiopathic scoliosis with a progressive action short brace (PASB: assessment of results according to the SRS committee on bracing and nonoperative management standardization criteria

Directory of Open Access Journals (Sweden)

Perisano Carlo

2009-09-01

Full Text Available Abstract Background The effectiveness of conservative treatment of scoliosis is controversial. Some studies suggest that brace is effective in stopping curve progression, whilst others did not report such an effect. The purpose of the present study was to effectiveness of Progressive Action Short Brace (PASB in the correction of thoraco-lumbar curves, in agreement with the Scoliosis Research Society (SRS Committee on Bracing and Nonoperative Management Standardisation Criteria. Methods Fifty adolescent females (mean age 11.8 ± 0.5 years with thoraco-lumbar curve and a pre-treatment Risser score ranging from 0 to 2 have been enrolled. The minimum duration of follow-up was 24 months (mean: 55.4 ± 44.5 months. Antero-posterior radiographs were used to estimate the curve magnitude (CM and the torsion of the apical vertebra (TA at 5 time points: beginning of treatment (t1, one year after the beginning of treatment (t2, intermediate time between t1 and t4 (t3, end of weaning (t4, 2-year minimum follow-up from t4 (t5. Three situations were distinguished: curve correction, curve stabilisation and curve progression. The Kruskal Wallis and Spearman Rank Correlation tests have been used as statistical tests. Results CM mean value was 29,30 ± 5,16 SD at t1 and 14,67 ± 7,65 SD at t5. TA was 12.70 ± 6,14 SD at t1 and 8,95 ± 5,82 at t5. The variation between measures of Cobb and Perdriolle degrees at t1,2,3,4,5 and between CM t5-t1 and TA t5-t1 were significantly different. Curve correction was accomplished in 94% of patients, whereas a curve stabilisation was obtained in 6% of patients. Conclusion The PASB, due to its peculiar biomechanical action on vertebral modelling, is highly effective in correcting thoraco-lumbar curves.

Performance Based Plastic Design of Concentrically Braced Frame attuned with Indian Standard code and its Seismic Performance Evaluation

Directory of Open Access Journals (Sweden)

Sejal Purvang Dalal

2015-12-01

Full Text Available In the Performance Based Plastic design method, the failure is predetermined; making it famous throughout the world. But due to lack of proper guidelines and simple stepwise methodology, it is not quite popular in India. In this paper, stepwise design procedure of Performance Based Plastic Design of Concentrically Braced frame attuned with the Indian Standard code has been presented. The comparative seismic performance evaluation of a six storey concentrically braced frame designed using the displacement based Performance Based Plastic Design (PBPD method and currently used force based Limit State Design (LSD method has also been carried out by nonlinear static pushover analysis and time history analysis under three different ground motions. Results show that Performance Based Plastic Design method is superior to the current design in terms of displacement and acceleration response. Also total collapse of the frame is prevented in the PBPD frame.

Stride length: the impact on propulsion and bracing ground reaction force in overhand throwing.

Science.gov (United States)

Ramsey, Dan K; Crotin, Ryan L

2018-03-26

Propulsion and bracing ground reaction force (GRF) in overhand throwing are integral in propagating joint reaction kinetics and ball velocity, yet how stride length effects drive (hind) and stride (lead) leg GRF profiles remain unknown. Using a randomised crossover design, 19 pitchers (15 collegiate and 4 high school) were assigned to throw 2 simulated 80-pitch games at ±25% of their desired stride length. An integrated motion capture system with two force plates and radar gun tracked each throw. Vertical and anterior-posterior GRF was normalised then impulse was derived. Paired t-tests identified whether differences between conditions were significant. Late in single leg support, peak propulsion GRF was statistically greater for the drive leg with increased stride. Stride leg peak vertical GRF in braking occurred before acceleration with longer strides, but near ball release with shorter strides. Greater posterior shear GRF involving both legs demonstrated increased braking with longer strides. Conversely, decreased drive leg propulsion reduced both legs' braking effects with shorter strides. Results suggest an interconnection between normalised stride length and GRF application in propulsion and bracing. This work has shown stride length to be an important kinematic factor affecting the magnitude and timing of external forces acting upon the body.

Next steps towards a Climate Innovation Centre in Ghana. Discussion Paper

International Nuclear Information System (INIS)

De Coninck, H.C.; Wuertenberger, L.; Akon-Yamga, G.

2011-03-01

A climate innovation centre is an institution aimed at enabling development through catalysing climate technology research, development, market creation and policy. This discussion paper discusses the possibilities, considerations and next steps for a Climate Innovation Centre (CIC) in Ghana based on new insights within the government of Ghana, a mapping of climate innovation in Ghana, new developments in the international climate negotiations and other multilateral processes, and analysis conducted by ECN. The conclusion is that a Climate Innovation Centre can fill significant gaps in climate resilient development in Ghana. It seems important that a Ghana CIC does not become yet another institution that focuses on basic research in the area of climate change. Rather, it should connect the dots of the Ghanaian climate innovation system and act as a knowledge facilitator, also for the private sector. Various models of climate innovation centres exist. Before choices are made for a model or a combination of models for Ghana, it is recommended to allow for a broad stakeholder process. The World Bank's infoDev programme could be a model for such a process. Such stakeholder engagement should be aligned with other policymaking processes on adaptation and low-carbon development, as well as related policy arenas, such as agriculture, transport, waste and energy.

Next steps towards a Climate Innovation Centre in Ghana. Discussion Paper

Energy Technology Data Exchange (ETDEWEB)

De Coninck, H.C.; Wuertenberger, L. [ECN Policy Studies, Petten (Netherlands); Akon-Yamga, G. [Science and Technology Policy Research Institute STEPRI, Accra (Guinea)

2011-03-15

A climate innovation centre is an institution aimed at enabling development through catalysing climate technology research, development, market creation and policy. This discussion paper discusses the possibilities, considerations and next steps for a Climate Innovation Centre (CIC) in Ghana based on new insights within the government of Ghana, a mapping of climate innovation in Ghana, new developments in the international climate negotiations and other multilateral processes, and analysis conducted by ECN. The conclusion is that a Climate Innovation Centre can fill significant gaps in climate resilient development in Ghana. It seems important that a Ghana CIC does not become yet another institution that focuses on basic research in the area of climate change. Rather, it should connect the dots of the Ghanaian climate innovation system and act as a knowledge facilitator, also for the private sector. Various models of climate innovation centres exist. Before choices are made for a model or a combination of models for Ghana, it is recommended to allow for a broad stakeholder process. The World Bank's infoDev programme could be a model for such a process. Such stakeholder engagement should be aligned with other policymaking processes on adaptation and low-carbon development, as well as related policy arenas, such as agriculture, transport, waste and energy.

Isopiestic determination of the osmotic and activity coefficients of the {l_brace}yKCl + (1 - y)K{sub 2}HPO{sub 4}{r_brace}(aq) system at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Popovic, Daniela Z. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 001 Belgrade (Serbia); Miladinovic, Jelena, E-mail: duma@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 001 Belgrade (Serbia); Todorovic, Milica D.; Zrilic, Milorad M. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 001 Belgrade (Serbia); Rard, Joseph A., E-mail: solution_chemistry2@comcast.net [4363 Claremont Way, Livermore, CA 94550 (United States)

2011-12-15

Highlights: > Isopiestic measurements were made for {l_brace}yKCl + (1 - y)K{sub 2}HPO{sub 4}{r_brace}(aq) at T = 298.15 K. > The resulting osmotic coefficients were represented by three thermodynamic models. > Activity coefficients from Pitzer model with Scatchard mixing terms are recommended. - Abstract: The osmotic coefficients of aqueous mixtures of KCl and K{sub 2}HPO{sub 4} have been measured at T = (298.15 {+-} 0.01) K by the isopiestic vapor pressure method over the range of ionic strengths from (2.3700 to 11.250) mol . kg{sup -1} using CaCl{sub 2}(aq) as the reference solution. Our new experimental results were modeled with an extended form of Pitzer's ion-interaction model equations, both with the usual mixing terms and with Scatchard's neutral-electrolyte mixing terms, and with the Clegg-Pitzer-Brimblecombe equations based on the mole-fraction-composition scale. There is a dearth of previously published isopiestic data for mixtures containing salts of HPO{sub 4}{sup 2-}(aq) and, consequently, no previous measurements are available for comparison with the present results. The present study yields Cl{sup -}HPO{sub 4}{sup 2-} mixing parameters for these three models that are needed for modeling the thermodynamic activities of solute components of natural waters and other complex aqueous electrolyte mixtures.

Ankles back in randomized controlled trial (ABrCt: braces versus neuromuscular exercises for the secondary prevention of ankle sprains. Design of a randomised controlled trial

Directory of Open Access Journals (Sweden)

Verhagen Evert ALM

2011-09-01

Full Text Available Abstract Background Ankle sprains are the most common sports and physical activity related injury. There is extensive evidence that there is a twofold increased risk for injury recurrence for at least one year post injury. In up to 50% of all cases recurrences result in disability and lead to chronic pain or instability, requiring prolonged medical care. Therefore ankle sprain recurrence prevention in athletes is essential. This RCT evaluates the effect of the combined use of braces and neuromuscular training (e.g. proprioceptive training/sensorimotor training/balance training against the individual use of either braces or neuromuscular training alone on ankle sprain recurrences, when applied to individual athletes after usual care. Methods/Design This study was designed as three way randomized controlled trial with one year follow-up. Healthy individuals between 12 and 70 years of age, who were actively participating in sports and who had sustained a lateral ankle sprain in the two months prior to inclusion, were eligible for inclusion. After subjects had finished ankle sprain treatment by means of usual care, they were randomised to any of the three study groups. Subjects in group 1 received an eight week neuromuscular training program, subjects in group 2 received a sports brace to be worn during all sports activities for the duration of one year, and group 3 received a combination of the neuromuscular training program and a sports brace to be worn during all sports activities for the duration of eight weeks. Outcomes were assessed at baseline and every month for 12 months therafter. The primary outcome measure was incidence of ankle sprain recurrences. Secondary outcome measures included the direct and indirect costs of recurrent injury, the severity of recurrent injury, and the residual complaints during and after the intervention. Discussion The ABrCt is the first randomized controlled trial to directly compare the secondary preventive

The interaction between d-dot's

International Nuclear Information System (INIS)

Hirayama, Masaki; Machida, Masahiko; Koyama, Tomio; Ishida, Takekazu; Kato, Masaru

2005-01-01

We investigated the interaction between two square d-dot's. The d-dot is the nano-scaled superconducting composite structure that is made of a d-wave superconducting dot embedded in the s-wave superconducting matrix. In the numerical calculation, using the finite element method, we solved the two-components Ginzburg-Landau equation self-consistently. We obtained two kinds of solutions, which can be considered as ferromagnetic and antiferromagnetic configurations, when two d-dot's are separated parallel and diagonally. Also we discuss the applicability of d-dot's as an artificial spin system where the interactions can be controlled by the fabrication

Accounting for multiple sources of uncertainty in impact assessments: The example of the BRACE study

Science.gov (United States)

O'Neill, B. C.

2015-12-01

Assessing climate change impacts often requires the use of multiple scenarios, types of models, and data sources, leading to a large number of potential sources of uncertainty. For example, a single study might require a choice of a forcing scenario, climate model, bias correction and/or downscaling method, societal development scenario, model (typically several) for quantifying elements of societal development such as economic and population growth, biophysical model (such as for crop yields or hydrology), and societal impact model (e.g. economic or health model). Some sources of uncertainty are reduced or eliminated by the framing of the question. For example, it may be useful to ask what an impact outcome would be conditional on a given societal development pathway, forcing scenario, or policy. However many sources of uncertainty remain, and it is rare for all or even most of these sources to be accounted for. I use the example of a recent integrated project on the Benefits of Reduced Anthropogenic Climate changE (BRACE) to explore useful approaches to uncertainty across multiple components of an impact assessment. BRACE comprises 23 papers that assess the differences in impacts between two alternative climate futures: those associated with Representative Concentration Pathways (RCPs) 4.5 and 8.5. It quantifies difference in impacts in terms of extreme events, health, agriculture, tropical cyclones, and sea level rise. Methodologically, it includes climate modeling, statistical analysis, integrated assessment modeling, and sector-specific impact modeling. It employs alternative scenarios of both radiative forcing and societal development, but generally uses a single climate model (CESM), partially accounting for climate uncertainty by drawing heavily on large initial condition ensembles. Strengths and weaknesses of the approach to uncertainty in BRACE are assessed. Options under consideration for improving the approach include the use of perturbed physics

Functional knee brace use effect on peak vertical ground reaction forces during drop jump landing.

Science.gov (United States)

Rishiraj, Neetu; Taunton, Jack E; Lloyd-Smith, Robert; Regan, William; Niven, Brian; Woollard, Robert

2012-12-01

The aim of the study was to investigate the landing strategies used by non-injured athletes while wearing functional knee braces (FKB, BR condition) during a drop jump task compared with non-injured, non-braced (NBR condition) subjects and also to ascertain whether accommodation to a FKB was possible by non-injured BR subjects. Twenty-three healthy male provincial and national basketball and field hockey athletes (age, 19.4 ± 3.0 years) were tested. Each subject was provided with a custom-fitted FKB. Five NBR testing sessions were performed over 3 days followed by five BR testing sessions also over 3 days, for a total of 17.5 h of testing per condition. Each subject performed eight trials of the drop jump task during each testing session per condition. Single-leg peak vertical ground reaction forces (PVGRF) and the time to PVGRF were recorded for each NBR and BR trail. The BR group mean PVGRF at landing was significantly lower (1,628 ± 405 N, 2.1 ± 0.5 BW versus 1,715 ± 403 N, 2.2 ± 0.5 BW, F (1,22) = 6.83, P = 0.01) compared with NBR subjects, respectively. The group mean time to PVGRF was not statistically longer during the BR condition (F (1,22) = 0.967, P = 0.3). Further, an accommodation trend was noted as percent performance difference decreased with continued FKB use. The significantly lower group mean PVGRF while using a FKB could keep traumatic forces from reaching the ACL until the active neuromuscular restraints are activated to provide protection to the knee joint ligaments. Also, accommodation to FKB is possible after approximately 14.0 h of brace use. The results of this paper will assist clinicians in providing information to their patients regarding a FKB ability to offer protection to an ACL-deficient knee or to address concerns about early muscle fatigue, energy expenditure, heart rate, and decrease in performance level. Prospective study, Level I.

Outcome of intensive outpatient rehabilitation and bracing in an adult patient with Scheuermann’s disease evaluated by radiologic imaging—a case report

Directory of Open Access Journals (Sweden)

Hagit Berdishevsky

2016-10-01

Full Text Available Abstract Background No studies examine the efficacy of intensive specific physical therapy (PT exercises along with brace for the adult with Scheuermann’s kyphosis (SK. The aim of this study was to examine the effects of intensive PT based on the Barcelona Scoliosis Physical Therapy School (BSPTS and SpinoMed brace on a 76-year-old female with SK. Case Description A 76-year-old female, diagnosed with SK as an adolescent, presented in October 2014 with thoracic hyperkyphosis T1 to T12 Cobb angle of 85° and lumbar hyper lordosis L1 to L5 Cobb angle of 70°. Lumbar scoliosis T12-L5 with 21° Cobb and vertebral rotation 2. Trunk translation in the sagittal plan was 4.5 cm. Intermittent low back pain 6/10 at worst. Quality-of-life score was 3.8 (SRS 22 questionnaire. Method The PT regimen included one-hour Schroth exercise sessions three times per week for 6 months. In addition, a home exercise program (HEP was recommended. Patient also wore a SpinoMed brace for 2 h per day. All tests and measurements were recorded before and after treatment. Results After a six-month treatment period the kyphosis Cobb angle was reduced to 70° and the lordosis Cobb angle improved to 57°. A recent x-ray (October 2015 showed another improvement in the sagittal plane with thoracic kyphosis measuring 64° and lumbar lordosis 55°. Lumbar curvature decreased to 12° and vertebral rotation to 1. The quality-of-life score showed improvement with a score of 4.5 on the SRS 22. Pain score diminished to 2. Trunk deviation improved by 2.2 cm. Conclusion These findings suggest that intensive and specific PT and bracing were successful for the treatment of this adult patient with SK.

Quantum dot spectroscopy

DEFF Research Database (Denmark)

Leosson, Kristjan

1999-01-01

Semiconductor quantum dots ("solid state atoms") are promising candidates for quantum computers and future electronic and optoelectronic devices. Quantum dots are zero-dimensional electronic systems and therefore have discrete energy levels, similar to atoms or molecules. The size distribution of...

Quantum dot spectroscopy

DEFF Research Database (Denmark)

Leosson, Kristjan

Semiconductor quantum dots ("solid-state atoms") are promising candidates for quantum computers and future electronic and optoelectronic devices. Quantum dots are zero-dimensional electronic systems and therefore have discrete energy levels, similar to atoms or molecules. The size distribution of...

Transport through overlapping states in quantum dots and double dot molecules

International Nuclear Information System (INIS)

Berkovits, R.

2006-01-01

Full Text: We shall review the transport properties of interacting quantum dots with overlapping orbitals for which the orthodox Coulomb blockade picture no longer holds. We shall concentrate on he conductance through a serial double dot structure for which the inter-dot tunneling is stronger than the tunneling to the leads. When the dots are occupied by 1 or 3 electrons the usual Kondo peak is observed. For the case in which 2 electrons occupy the molecule a singlet is formed. Nevertheless, the conductance in that case has a constant non-zero value, and might even be equal to the maximum conductance of 2e 2 /h for certain values of the molecule parameters. We show that this is the result of the subtle interplay between the symmetric and anti-symmetric orbitals of the molecule caused by interactions and interference

A user`s guide to LUGSAN II. A computer program to calculate and archive lug and sway brace loads for aircraft-carried stores

Energy Technology Data Exchange (ETDEWEB)

Dunn, W.N. [Sandia National Labs., Albuquerque, NM (United States). Mechanical and Thermal Environments Dept.

1998-03-01

LUG and Sway brace ANalysis (LUGSAN) II is an analysis and database computer program that is designed to calculate store lug and sway brace loads for aircraft captive carriage. LUGSAN II combines the rigid body dynamics code, SWAY85, with a Macintosh Hypercard database to function both as an analysis and archival system. This report describes the LUGSAN II application program, which operates on the Macintosh System (Hypercard 2.2 or later) and includes function descriptions, layout examples, and sample sessions. Although this report is primarily a user`s manual, a brief overview of the LUGSAN II computer code is included with suggested resources for programmers.

Synthesis of quantum dots

Science.gov (United States)

McDaniel, Hunter

2017-10-17

Common approaches to synthesizing alloyed quantum dots employ high-cost, air-sensitive phosphine complexes as the selenium precursor. Disclosed quantum dot synthesis embodiments avoid these hazardous and air-sensitive selenium precursors. Certain embodiments utilize a combination comprising a thiol and an amine that together reduce and complex the elemental selenium to form a highly reactive selenium precursor at room temperature. The same combination of thiol and amine acts as the reaction solvent, stabilizing ligand, and sulfur source in the synthesis of quantum dot cores. A non-injection approach may also be used. The optical properties of the quantum dots synthesized by this new approach can be finely tuned for a variety of applications by controlling size and/or composition of size and composition. Further, using the same approach, a shell can be grown around a quantum dot core that improves stability, luminescence efficiency, and may reduce toxicity.

One-pot and ultrafast synthesis of nitrogen and phosphorus co-doped carbon dots possessing bright dual wavelength fluorescence emission

Science.gov (United States)

Sun, Xiangcheng; Brückner, Christian; Lei, Yu

2015-10-01

Very brief microwave heating of aniline, ethylene diamine, and phosphoric acid in water at ambient pressure generated nitrogen and phosphorus co-doped carbon dots (N,P-CDs) that exhibit bright dual blue (centred at 450 nm; 51% quantum yield) and green (centred at 510 nm, 38% quantum yield) fluorescence emission bands. The N,P-CDs were characterized using TEM, XRD, XPS, IR, UV-vis, and fluorescence spectroscopy, demonstrating their partially crystalline carbon, partially amorphous structures, and the incorporation of O, N, and P into the carbogenic scaffold. The N,P-CDs demonstrated excitation-dependent and nearly pH-independent emission properties. The unique dual emission properties lay the foundation for the use of N,P-CDs in ratiometric sensing applications.Very brief microwave heating of aniline, ethylene diamine, and phosphoric acid in water at ambient pressure generated nitrogen and phosphorus co-doped carbon dots (N,P-CDs) that exhibit bright dual blue (centred at 450 nm; 51% quantum yield) and green (centred at 510 nm, 38% quantum yield) fluorescence emission bands. The N,P-CDs were characterized using TEM, XRD, XPS, IR, UV-vis, and fluorescence spectroscopy, demonstrating their partially crystalline carbon, partially amorphous structures, and the incorporation of O, N, and P into the carbogenic scaffold. The N,P-CDs demonstrated excitation-dependent and nearly pH-independent emission properties. The unique dual emission properties lay the foundation for the use of N,P-CDs in ratiometric sensing applications. Electronic supplementary information (ESI) available: Detailed experimental section, XRD, FTIR, explosive sensing and the applications results. See DOI: 10.1039/c5nr05549k

Quantum Dots: Theory

Energy Technology Data Exchange (ETDEWEB)

Vukmirovic, Nenad; Wang, Lin-Wang

2009-11-10

This review covers the description of the methodologies typically used for the calculation of the electronic structure of self-assembled and colloidal quantum dots. These are illustrated by the results of their application to a selected set of physical effects in quantum dots.

49 CFR 40.13 - How do DOT drug and alcohol tests relate to non-DOT tests?

Science.gov (United States)

2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false How do DOT drug and alcohol tests relate to non... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Employer Responsibilities § 40.13 How do DOT drug and... non-DOT drug and alcohol testing programs. This prohibition includes the use of the DOT forms with...

DotFETs: MOSFETs strained by a Single SiGE dot in a Low-Temperature ELA Technology

OpenAIRE

Biasotto, C.

2011-01-01

The work presented in this thesis was performed in the context of the European Sixth Framework Program FP6 project “Disposable Dot Field Effect Transistor for High Speed Si Integrated Circuits”, referred to as the D-DotFET project. The project had the goal of realizing strain-enhanced mobility in CMOS transistors by transferring strain from a self-assembled germanium dot to the channel of a transistor fabricated above the dot. The initial idea was to dispose of the Ge dot underneath the chann...

On the diameter of dot-critical graphs

Directory of Open Access Journals (Sweden)

Doost Ali Mojdeh

2009-01-01

Full Text Available A graph G is \\(k\\-dot-critical (totaly \\(k\\-dot-critical if \\(G\\ is dot-critical (totaly dot-critical and the domination number is \\(k\\. In the paper [T. Burtona, D. P. Sumner, Domination dot-critical graphs, Discrete Math, 306 (2006, 11-18] the following question is posed: What are the best bounds for the diameter of a \\(k\\-dot-critical graph and a totally \\(k\\-dot-critical graph \\(G\\ with no critical vertices for \\(k \\geq 4\\? We find the best bound for the diameter of a \\(k\\-dot-critical graph, where \\(k \\in\\{4,5,6\\}\\ and we give a family of \\(k\\-dot-critical graphs (with no critical vertices with sharp diameter \\(2k-3\\ for even \\(k \\geq 4\\.

Hyperdense dots mimicking microcalcifications : Mammographic findings

International Nuclear Information System (INIS)

Kim, Nam Hyeon; Park, Jeong Mi; Goo, Hyun Woo; Bang, Sun Woo

1996-01-01

To differentiate fine hyperdense dots mimicking microcalcifications from true microcalcifications on mammography. Mammograms showing hyperdense dots in ten patients (mean age, 59 years) were evaluated. Two radiologists were asked to differentiate with the naked eye the hyperdense dots seen on ten mammograms and proven microcalcifications seen on ten mammograms. Densitometry was also performed for all lesions and the contrast index was calculated. The shape and distribution of the hyperdense dots were evaluated and enquires were made regarding any history of breast disease and corresponding treatment. Biopsies were performed for two patients with hyperdense dots. Two radiologists made correct diagnoses in 19/20 cases(95%). The contrast index was 0.10-0.88 (mean 0.58) for hyperdense dots and 0.02-0.45 (mean 0.17) for true microcalcifications. The hyperdense dots were finer and homogeneously rounder than the microcalcifications. Distribution of the hyperdense dots was more superficial in subcutaneous fat (seven cases) and subareolar area (six cases). All ten patients with hyperdense dots had history of mastitis and abscesses and had been treated by open drainage (six cases) and/or folk remedy (four cases). In eight patients, herb patches had been attached. Biopsies of hyperdense dots did not show any microcalcification or evidence of malignancy. These hyperdense dots were seen mainly in older patients. Their characteristic density, shape, distribution and clinical history makes differential diagnosis from true microcalcifications easy and could reduce unnecessary diagnostic procedures such as surgical biopsy

Vectorization of DOT3.5 code

International Nuclear Information System (INIS)

Nonomiya, Iwao; Ishiguro, Misako; Tsutsui, Tsuneo

1990-07-01

In this report, we describe the vectorization of two-dimensional Sn-method radiation transport code DOT3.5. Vectorized codes are not only the NEA original version developed at ORNL but also the versions improved by JAERI: DOT3.5 FNS version for fusion neutronics analyses, DOT3.5 FER version for fusion reactor design, and ESPRIT module of RADHEAT-V4 code system for radiation shielding and radiation transport analyses. In DOT3.5, input/output processing time amounts to a great part of the elapsed time when a large number of energy groups and/or a large number of spatial mesh points are used in the calculated problem. Therefore, an improvement has been made for the speedup of input/output processing in the DOT3.5 FNS version, and DOT-DD (Double Differential cross section) code. The total speedup ratio of vectorized version to the original scalar one is 1.7∼1.9 for DOT3.5 NEA version, 2.2∼2.3 fro DOT3.5 FNS version, 1.7 for DOT3.5 FER version, and 3.1∼4.4 for RADHEAT-V4, respectively. The elapsed times for improved DOT3.5 FNS version and DOT-DD are reduced to 50∼65% that of the original version by the input/output speedup. In this report, we describe summary of codes, the techniques used for the vectorization and input/output speedup, verification of computed results, and speedup effect. (author)

Hyperdense dots mimicking microcalcifications : Mammographic findings

Energy Technology Data Exchange (ETDEWEB)

Kim, Nam Hyeon; Park, Jeong Mi; Goo, Hyun Woo; Bang, Sun Woo [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

1996-12-01

To differentiate fine hyperdense dots mimicking microcalcifications from true microcalcifications on mammography. Mammograms showing hyperdense dots in ten patients (mean age, 59 years) were evaluated. Two radiologists were asked to differentiate with the naked eye the hyperdense dots seen on ten mammograms and proven microcalcifications seen on ten mammograms. Densitometry was also performed for all lesions and the contrast index was calculated. The shape and distribution of the hyperdense dots were evaluated and enquires were made regarding any history of breast disease and corresponding treatment. Biopsies were performed for two patients with hyperdense dots. Two radiologists made correct diagnoses in 19/20 cases(95%). The contrast index was 0.10-0.88 (mean 0.58) for hyperdense dots and 0.02-0.45 (mean 0.17) for true microcalcifications. The hyperdense dots were finer and homogeneously rounder than the microcalcifications. Distribution of the hyperdense dots was more superficial in subcutaneous fat (seven cases) and subareolar area (six cases). All ten patients with hyperdense dots had history of mastitis and abscesses and had been treated by open drainage (six cases) and/or folk remedy (four cases). In eight patients, herb patches had been attached. Biopsies of hyperdense dots did not show any microcalcification or evidence of malignancy. These hyperdense dots were seen mainly in older patients. Their characteristic density, shape, distribution and clinical history makes differential diagnosis from true microcalcifications easy and could reduce unnecessary diagnostic procedures such as surgical biopsy.

Peculiarities of component interaction in {l_brace}Gd, Er{r_brace}-V-Sn Ternary systems at 870 K and crystal structure of RV{sub 6}Sn{sub 6} stannides

Energy Technology Data Exchange (ETDEWEB)

Romaka, L., E-mail: romakal@franko.lviv.ua [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya str. 6, 79005 Lviv (Ukraine); Stadnyk, Yu. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya str. 6, 79005 Lviv (Ukraine); Romaka, V.V. [Department of Materials Engineering and Applied Physics, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Demchenko, P.; Stadnyshyn, M.; Konyk, M. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya str. 6, 79005 Lviv (Ukraine)

2011-09-08

Highlights: > {l_brace}Gd, Er{r_brace}-V-Sn ternary systems at 870 K are characterized by formation of stannides with general compositions RV{sub 6}Sn{sub 6}. > Isostructural RV{sub 6}Sn{sub 6} compounds were also found with Y, Dy, Ho, Tm, and Lu. > The crystal structure of RV{sub 6}Sn{sub 6} compounds was determined by powder diffraction method. > Structural analysis showed that RV{sub 6}Sn{sub 6} compounds (R = Gd, Dy-Tm, Lu) are disordered; YV{sub 6}Sn{sub 6} is characterized by structure ordering. - Abstract: The phase equilibria in the Gd-V-Sn and Er-V-Sn ternary systems were studied at 870 K by means of X-ray and metallographic analyses in the whole concentration range. Both Gd-V-Sn and Er-V-Sn systems are characterized by formation of one ternary compound at investigated temperature, with stoichiometry RV{sub 6}Sn{sub 6} (SmMn{sub 6}Sn{sub 6}-type, space group P6/mmm, a = 0.55322(3) nm, c = 0.91949(7) nm for Gd, a = 0.55191(2) nm, c = 0.91869(8) nm for Er). Solubility of the third component in the binary compounds was not observed. Compounds with the SmMn{sub 6}Sn{sub 6}-type were also found with Dy, Ho, Tm, and Lu, while YV{sub 6}Sn{sub 6} compound crystallizes in HfFe{sub 6}Ge{sub 6} structure type. All investigated compounds are the first ternary stannides with rare earth elements and vanadium.

The effect of taping versus semi-rigid bracing on patient outcome and satisfaction in ankle sprains: a prospective, randomized controlled trial.

Science.gov (United States)

Lardenoye, Sacha; Theunissen, Ed; Cleffken, Berry; Brink, Peter Rg; de Bie, Rob A; Poeze, Martijn

2012-05-28

Functional treatment is a widely used and generally accepted treatment for ankle sprain. A meta-analysis comparing the different functional treatment options could not make definitive conclusions regarding the effectiveness, and until now, little was known about patient satisfaction in relation to the outcome. Patients with acute ankle sprain received rest, ice, compression and elevation with an compressive bandage at the emergency department. After 5-7 days, 100 patients with grade II and III sprains were randomized into two groups: one group was treated with tape and the other with a semi-rigid ankle brace, both for 4 weeks. Post-injury physical and proprioceptive training was standardized. As primary outcome parameter patient satisfaction and skin complications were evaluated using a predefined questionnaire and numeric rating scale. As secondary outcome parameter the ankle joint function was assessed using the Karlsson scoring scale and range of motion. Patient-reported comfort and satisfaction during treatment with a semi-rigid brace was significantly increased. The rate of skin complication in this group was significantly lower compared to the tape group (14.6% versus 59.1%, P ankle joint was similar between the two treatment groups, as well as reported pain. Treatment of acute ankle sprain with semi-rigid brace leads to significantly higher patient comfort and satisfaction, both with similar good outcome.

From DOT to Dotty

CERN Multimedia

CERN. Geneva

2017-01-01

- Module types are interfaces, which can be abstracted. In this talk Martin will present DOT, a particularly simple calculus that can express systems following these principles. DOT has been developed as the foundation of the next version of Scala. He will also report on dotty, a new Scala compiler that implements the constructs of DOT in its core data structures and that uses the lessons learned to drive Scala’s evolution.

Improving the seismic performance of eccentrically braced frames by using a ductile element

Directory of Open Access Journals (Sweden)

Morteza Naghipour

2017-11-01

Full Text Available Stability of structures against earthquake is much important to prevent total or partial failure of structures and loss of financial and human investments of people and country. Eccentrically braced frames, as one of the most commonly used earthquake resistant systems, with good ductility and toughness, have different arrangements; one of them is Link beam-to-column connection. This type of connection was considered as bending form before the North Ridge earthquake (1994. But conducted research after the North Ridge Earthquake showed that the link beam-to-column connections were subjected to brittle failure, similar to connections which were located in Moment frames. So, after the North Ridge Earthquake, researchers began looking for ways to improve these types of connections, which indicates necessity of research in this field more than before. In this study, a new type of Energy absorption was introduced.  This absorption consists of a ring which increases the ductility and energy absorption of earthquake and a box to increase the bearing capacity which is connected to the ring through connection plates. for evaluating the performance of the proposed elements in steel frames with eccentrically braces, under nonlinear time history analysis, the OpenSees software has been used. The obtained Hysteresis curves suggest that introduced element can act as an energy absorbing member and a fuse to Reducing damage to structures with reduced rotation of link-beam, Cutting base and Relative story displacement in addition to providing the necessary ductility.

From micro- to nanomagnetic dots: evolution of the eigenmode spectrum on reducing the lateral size

International Nuclear Information System (INIS)

Carlotti, G; Madami, M; Gubbiotti, G; Tacchi, S; Hartmann, F; Emmerling, M; Kamp, M; Worschech, L

2014-01-01

Brillouin light scattering experiments and micromagnetic simulations have been exploited to investigate the spectrum of thermally excited magnetic eigenmodes in 10 nm-thick elliptical Permalloy dots, when the longer axis D is scaled down from about 1000 to 100 nm. It is shown that for D larger than about 200 nm the characteristics of the spin-wave eigenmodes are dominated by dipolar energy, while for D in the range of about 100 to 200 nm exchange energy effects cause qualitative and quantitative differences in the spin-wave spectrum. In this ‘mesoscopic’ regime, the usual classification scheme, involving one fundamental mode with large average magnetization and many other modes collected in families with specific symmetries, no longer holds. Rather, one finds the simultaneous presence of two modes with ‘fundamental’ character, i.e. with a significant and comparable value of the average dynamical magnetization: the former is at larger frequency and has its maximum amplitude at the dot's centre, while the latter occurs at lower frequency and is localized at the dot's edges. Interestingly, the maximum intensity swaps from the higher frequency mode to the lower frequency one, just when the dot size is reduced from about 200 to 100 nm. This is relevant in view of the exploitation of nanodots for the design of nanomagnetic devices with lateral dimensions in the above interval, such as memory cells, logic gates, reading heads and spin-torque oscillators. (paper)

From micro- to nanomagnetic dots: evolution of the eigenmode spectrum on reducing the lateral size

Science.gov (United States)

Carlotti, G.; Gubbiotti, G.; Madami, M.; Tacchi, S.; Hartmann, F.; Emmerling, M.; Kamp, M.; Worschech, L.

2014-07-01

Brillouin light scattering experiments and micromagnetic simulations have been exploited to investigate the spectrum of thermally excited magnetic eigenmodes in 10 nm-thick elliptical Permalloy dots, when the longer axis D is scaled down from about 1000 to 100 nm. It is shown that for D larger than about 200 nm the characteristics of the spin-wave eigenmodes are dominated by dipolar energy, while for D in the range of about 100 to 200 nm exchange energy effects cause qualitative and quantitative differences in the spin-wave spectrum. In this ‘mesoscopic’ regime, the usual classification scheme, involving one fundamental mode with large average magnetization and many other modes collected in families with specific symmetries, no longer holds. Rather, one finds the simultaneous presence of two modes with ‘fundamental’ character, i.e. with a significant and comparable value of the average dynamical magnetization: the former is at larger frequency and has its maximum amplitude at the dot's centre, while the latter occurs at lower frequency and is localized at the dot's edges. Interestingly, the maximum intensity swaps from the higher frequency mode to the lower frequency one, just when the dot size is reduced from about 200 to 100 nm. This is relevant in view of the exploitation of nanodots for the design of nanomagnetic devices with lateral dimensions in the above interval, such as memory cells, logic gates, reading heads and spin-torque oscillators.

Effect of Group Exercising and Adjusting the Brace at Shorter Intervals on Cobb Angle and Quality of Life of Patients with Idiopathic Scoliosis

Directory of Open Access Journals (Sweden)

Zahra Hedayati

2016-01-01

Full Text Available Objective: Bracing along with exercising is the most effective protocol in patients with idiopathic scoliosis which have Cobb angles of 25 to 45 degrees. However, since the psychological aspects of scoliosis treatment may affect the quality of life, and the exact time for adjusting the pads of Milwaukee brace is unknown; Therefore the aim of this study was evaluating the effect of exercising in a group, with adjusting the brace in shorter intervals, in compare to routine protocol, in the treatment of idiopathic scoliosis. Matterials & Methods: Thirty-four patients with idiopathic scoliosis which had Cobb angles of 50 to 15 degrees were included in this study and were divided into experimental and control groups. The patients of two groups participated in an eleven-week treatment program, differ between the two groups. Quality of life scores of both groups were evaluated before and after intervention using SRS-22 questionnaire, as well as scoliosis angles before and after the intervention according to the primary and secondary radiographic X-rays. Results: Statistical analysis was performed using Paired T-Test in each group, and Independent T-Test between the two groups before and after treatment. The severity of scoliosis curvature and satisfaction domain of the experimental group was reduced significantly in compared with the control group, after intervention (P=0.04. Moreover in the case of  the quality of life in patients with Cobb angles less than 30 degrees, compared with patients with Cobb angles greater than 31 degrees, in the domains of self-image, satisfaction, and total score, the difference was significant (P<0.05. Conclusion: Adjusting the brace at shorter intervals along with exercising as a group, during the eleven weeks of treatment, has increased satisfaction and reduced the scoliosis Cobb angles of patients.

Studies on the relationship between Pitzer's equation and medium effect: the system of HCl + H{sub 2}SO{sub 4} in {l_brace}0.06455C{sub 2}H{sub 5}OH + 0.93545H{sub 2}O{r_brace}

Energy Technology Data Exchange (ETDEWEB)

Lu Xingmei E-mail: lxmqt@sohu.com; Xu Weiguo; Chang Xiaohong; Lu Dianzhen; Yang Jiazhen

2004-03-01

The second ionization constant of sulfuric acid in mixed solvent, K{sub 2}, was determined by e.m.f. of cell without liquid junction: (Pt,H{sub 2}(101.325 kPa) vertical bar HCl(m{sub 1}),H{sub 2}SO{sub 4}(m{sub 2}),{l_brace}ethanol(x=0.06455)+water(x=0.93545){r_brace} vertical bar AgCl-Ag))over the temperatures (278.15 to 318.15) K, where x is mole fraction. Combining Owen's definition of medium effect with Pitzer's equations, the values of combination parameters: ({lambda}{sub nHS}+{lambda}{sub nCl}-{lambda}{sub nS})+(3/2)m{sub n}({mu}{sub nnHS}+{mu}{sub nnC=} l-{mu}{sub nnS}),(1/2)({xi}{sub nHHS}+{xi}{sub nHCl}-{xi}{sub nHS}), that represent the interactions between ions and ethanol were obtained at 298.15 K.

Stark shifting two-electron quantum dot

International Nuclear Information System (INIS)

Dineykhan, M.; Zhaugasheva, S.A.; Duysebaeva, K.S.

2003-01-01

Advances in modern technology make it possible to create semiconducting nano-structures (quantum dot) in which a finite number of electrons are 'captured' in a bounded volume. A quantum dot is associated with a quantum well formed at the interface, between two finite-size semiconductors owing to different positions of the forbidden gaps on the energy scale in these semiconductors. The possibility of monitoring and controlling the properties of quantum dots attracts considerable attention to these objects, as a new elemental basis for future generations of computers. The quantum-mechanical effects and image potential play a significant role in the description of the formation mechanism quantum dot, and determined the confinement potential in a two-electron quantum dot only for the spherical symmetric case. In the present talk, we considered the formation dynamics of two-electron quantum dot with violation of spherical symmetry. So, we have standard Stark potential. The energy spectrum two-electron quantum dot were calculated. Usually Stark interactions determined the tunneling phenomena between quantum dots

Hydrogenic impurity in double quantum dots

International Nuclear Information System (INIS)

Wang, X.F.

2007-01-01

The ground state binding energy and the average interparticle distances for a hydrogenic impurity in double quantum dots with Gaussian confinement potential are studied by the variational method. The probability density of the electron is calculated, too. The dependence of the binding energy on the impurity position is investigated for GaAs quantum dots. The result shows that the binding energy has a minimum as a function of the distance between the two quantum dots when the impurity is located at the center of one quantum dot or at the center of the edge of one quantum dot. When the impurity is located at the center of the two dots, the binding energy decreases monotonically

Emission switching in carbon dots coated CdTe quantum dots driving by pH dependent hetero-interactions

Energy Technology Data Exchange (ETDEWEB)

Dai, Xiao; Wang, Hao; Yi, Qinghua; Wang, Yun; Cong, Shan; Zhao, Jie; Sun, Yinghui; Zou, Guifu, E-mail: zouguifu@suda.edu.cn, E-mail: jiexiong@uestc.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Qian, Zhicheng [School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Huang, Jianwen; Xiong, Jie, E-mail: zouguifu@suda.edu.cn, E-mail: jiexiong@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Luo, Hongmei [Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, New Mexico 88003 (United States)

2015-11-16

Due to the different emission mechanism between fluorescent carbon dots and semiconductor quantum dots (QDs), it is of interest to explore the potential emission in hetero-structured carbon dots/semiconducting QDs. Herein, we design carbon dots coated CdTe QDs (CDQDs) and investigate their inherent emission. We demonstrate switchable emission for the hetero-interactions of the CDQDs. Optical analyses indicate electron transfer between the carbon dots and the CdTe QDs. A heterojunction electron process is proposed as the driving mechanism based on N atom protonation of the carbon dots. This work advances our understanding of the interaction mechanism of the heterostructured CDQDs and benefits the future development of optoelectronic nanodevices with new functionalities.

Spin storage in quantum dot ensembles and single quantum dots

International Nuclear Information System (INIS)

Heiss, Dominik

2009-01-01

This thesis deals with the investigation of spin relaxation of electrons and holes in small ensembles of self-assembled quantum dots using optical techniques. Furthermore, a method to detect the spin orientation in a single quantum dot was developed in the framework of this thesis. A spin storage device was used to optically generate oriented electron spins in small frequency selected quantum dot ensembles using circularly polarized optical excitation. The spin orientation can be determined by the polarization of the time delayed electroluminescence signal generated by the device after a continuously variable storage time. The degree of spin polarized initialization was found to be limited to 0.6 at high magnetic fields, where anisotropic effects are compensated. The spin relaxation was directly measured as a function of magnetic field, lattice temperature and s-shell transition energy of the quantum dot by varying the spin storage time up to 30 ms. Very long spin lifetimes are obtained with a lower limit of T 1 =20 ms at B=4 T and T=1 K. A strong magnetic field dependence T 1 ∝B -5 has been observed for low temperatures of T=1 K which weakens as the temperature is increased. In addition, the temperature dependence has been determined with T 1 ∝T -1 . The characteristic dependencies on magnetic field and temperature lead to the identification of the spin relaxation mechanism, which is governed by spin-orbit coupling and mediated by single phonon scattering. This finding is qualitatively supported by the energy dependent measurements. The investigations were extended to a modified device design that enabled studying the spin relaxation dynamics of heavy holes in self-assembled quantum dots. The measurements show a polarization memory effect for holes with up to 0.1 degree of polarization. Furthermore, investigations of the time dynamics of the hole spin relaxation reveal surprisingly long lifetimes T 1 h in the microsecond range, therefore, comparable with

Spin storage in quantum dot ensembles and single quantum dots

Energy Technology Data Exchange (ETDEWEB)

Heiss, Dominik

2009-10-15

This thesis deals with the investigation of spin relaxation of electrons and holes in small ensembles of self-assembled quantum dots using optical techniques. Furthermore, a method to detect the spin orientation in a single quantum dot was developed in the framework of this thesis. A spin storage device was used to optically generate oriented electron spins in small frequency selected quantum dot ensembles using circularly polarized optical excitation. The spin orientation can be determined by the polarization of the time delayed electroluminescence signal generated by the device after a continuously variable storage time. The degree of spin polarized initialization was found to be limited to 0.6 at high magnetic fields, where anisotropic effects are compensated. The spin relaxation was directly measured as a function of magnetic field, lattice temperature and s-shell transition energy of the quantum dot by varying the spin storage time up to 30 ms. Very long spin lifetimes are obtained with a lower limit of T{sub 1}=20 ms at B=4 T and T=1 K. A strong magnetic field dependence T{sub 1}{proportional_to}B{sup -5} has been observed for low temperatures of T=1 K which weakens as the temperature is increased. In addition, the temperature dependence has been determined with T{sub 1}{proportional_to}T{sup -1}. The characteristic dependencies on magnetic field and temperature lead to the identification of the spin relaxation mechanism, which is governed by spin-orbit coupling and mediated by single phonon scattering. This finding is qualitatively supported by the energy dependent measurements. The investigations were extended to a modified device design that enabled studying the spin relaxation dynamics of heavy holes in self-assembled quantum dots. The measurements show a polarization memory effect for holes with up to 0.1 degree of polarization. Furthermore, investigations of the time dynamics of the hole spin relaxation reveal surprisingly long lifetimes T{sub 1}{sup h

Incommensurate phases in the improper ferroelastic MgGeF sub 6 centre dot 6H sub 2 O:Mn sup 2 sup + studied by means of EPR

CERN Document Server

Skrylnik, P G

2002-01-01

The results of an EPR study of the inhomogeneous phases existing in the temperature interval T sub C = 311.0 +- 0.3 K < T < T sub i sub 1 = 403 +- 0.3 K in improper ferroelastic crystals of MgGeF sub 6 centre dot 6H sub 2 O:Mn sup 2 sup + are presented. On the basis of the analysis of the temperature and angle dependences of the experimental parameters and numerical calculations, the conclusion has been drawn that at T sub i sub 1 the crystals considered undergo a transition to a structurally modulated phase and the order parameter of this transition may be the angle of the Mg[H sub 2 O] sub 6 sup 2 sup + octahedra rotation around the crystal C sub 3 -axis. From T sub i sub 1 to T sub C the modes of the modulated phase follow according to a completely classical scenario for incommensurate crystals: the origin of the incommensurate structure with plane-wave modulation at T sub i sub 1 , the appearance of structural phase solitons below T sub i sub 2 = 380 +- 0.3 K and decrease of the soliton density to v...

Speeds of sound in {l_brace}(1 - x)CH{sub 4} + xN{sub 2}{r_brace} with x = (0.10001, 0.19999, and 0.5422) at temperatures between 170 K and 400 K and pressures up to 30 MPa

Energy Technology Data Exchange (ETDEWEB)

Estela-Uribe, J.F. [Facultad de Ingenieria, Universidad Javeriana-Cali, Calle 18, 118-250 Cali (Colombia); Trusler, J.P.M. [Department of Chemical Engineering, Imperial College London, London SW7 2AZ (United Kingdom)]. E-mail: m.trusler@imperial.ac.uk; Chamorro, C.R. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain); Segovia, J.J. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain); Martin, M.C. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain); Villamanan, M.A. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain)

2006-07-15

The speed of sound in {l_brace}(1 - x)CH{sub 4} + xN{sub 2}{r_brace} has been measured with a spherical acoustic resonator. Two mixtures with x = (0.10001 and 0.19999) were studied along isotherms at temperatures between 220 K and 400 K with pressures up to 20 MPa; a few additional measurements at p = (25 and 30) MPa are also reported. A third mixture with x = 0.5422 was studied along pseudo-isochores at amount-of-substance densities between 0.2 mol . dm{sup -3} and 5 mol . dm{sup -3}. Corrections for molecular vibrational relaxation are discussed in detail and relaxation times are reported. The overall uncertainty of the measured speeds of sound is estimated to be not worse than {+-}0.02%, except for those measurements in the mixture with x = 0.5422 that lie along the pseduo-isochore at the highest amount-of-substance density. The results have been compared with the predictions of several equations of state used for natural gas systems.

A 2x2 quantum dot array with controllable inter-dot tunnel couplings

OpenAIRE

Mukhopadhyay, Uditendu; Dehollain, Juan Pablo; Reichl, Christian; Wegscheider, Werner; Vandersypen, Lieven M. K.

2018-01-01

The interaction between electrons in arrays of electrostatically defined quantum dots is naturally described by a Fermi-Hubbard Hamiltonian. Moreover, the high degree of tunability of these systems make them a powerful platform to simulate different regimes of the Hubbard model. However, most quantum dot array implementations have been limited to one-dimensional linear arrays. In this letter, we present a square lattice unit cell of 2$\\times$2 quantum dots defined electrostatically in a AlGaA...

Bracing superior to neuromuscular training for the prevention of self-reported recurrent ankle sprains: a three-arm randomised controlled trial

NARCIS (Netherlands)

Janssen, K.W.; van Mechelen, W.; Verhagen, E.A.L.M.

2014-01-01

Background Ankle sprain is the most common sportsrelated injury with a high rate of recurrence and associated costs. Recent studies have emphasised the effectiveness of both neuromuscular training and bracing for the secondary prevention of ankle sprains. Aim To evaluate the effectiveness of

Dicke states in multiple quantum dots

Science.gov (United States)

Sitek, Anna; Manolescu, Andrei

2013-10-01

We present a theoretical study of the collective optical effects which can occur in groups of three and four quantum dots. We define conditions for stable subradiant (dark) states, rapidly decaying super-radiant states, and spontaneous trapping of excitation. Each quantum dot is treated like a two-level system. The quantum dots are, however, realistic, meaning that they may have different transition energies and dipole moments. The dots interact via a short-range coupling which allows excitation transfer across the dots, but conserves the total population of the system. We calculate the time evolution of single-exciton and biexciton states using the Lindblad equation. In the steady state the individual populations of each dot may have permanent oscillations with frequencies given by the energy separation between the subradiant eigenstates.

Dose, image quality and spine modeling assessment of biplanar EOS micro-dose radiographs for the follow-up of in-brace adolescent idiopathic scoliosis patients.

Science.gov (United States)

Morel, Baptiste; Moueddeb, Sonia; Blondiaux, Eleonore; Richard, Stephen; Bachy, Manon; Vialle, Raphael; Ducou Le Pointe, Hubert

2018-05-01

The aim of this study was to compare the radiation dose, image quality and 3D spine parameter measurements of EOS low-dose and micro-dose protocols for in-brace adolescent idiopathic scoliosis (AIS) patients. We prospectively included 25 consecutive patients (20 females, 5 males) followed for AIS and undergoing brace treatment. The mean age was 12 years (SD 2 years, range 8-15 years). For each patient, in-brace biplanar EOS radiographs were acquired in a standing position using both the conventional low-dose and micro-dose protocols. Dose area product (DAP) was systematically recorded. Diagnostic image quality was qualitatively assessed by two radiologists for visibility of anatomical structures. The reliability of 3D spine modeling between two operators was quantitatively evaluated for the most clinically relevant 3D radiological parameters using intraclass correlation coefficient (ICC). The mean DAP for the posteroanterior and lateral acquisitions was 300 ± 134 and 433 ± 181 mGy cm 2 for the low-dose radiographs, and 41 ± 19 and 81 ± 39 mGy cm 2 for micro-dose radiographs. Image quality was lower with the micro-dose protocol. The agreement was "good" to "very good" for all measured clinical parameters when comparing the low-dose and micro-dose protocols (ICC > 0.73). The micro-dose protocol substantially reduced the delivered dose (by a factor of 5-7 compared to the low-dose protocol) in braced children with AIS. Although image quality was reduced, the micro-dose protocol proved to be adapted to radiological follow-up, with adequate image quality and reliable clinical measurements. These slides can be retrieved under Electronic Supplementary Material.

Corrosion studies of thermally sensitised AGR fuel element brace in pH7 and pH9.2 borate solutions

International Nuclear Information System (INIS)

Tyfield, S.P.; Smith, C.A.

1987-04-01

Brace and cladding of AGR fuel elements sensitised in reactor are susceptible to intergranular and crevice corrosion, which may initiate in the pH7 borate pond storage environment of CEGB/SSEB stations. This report considers the benefit in corrosion control that is provided by raising the pond solution pH to 9.2, whilst maintaining the boron level at 1250 gm -3 . The greater corrosion protection provided by pH9.2 solution compared to the pH7 borate solution is demonstrated by a series of tests with non-active laboratory sensitised brace samples exposed to solutions dosed with chloride or sulphate in order to promote localised corrosion. The corrosion tests undertaken consisted of 5000 hour immersions at 32 0 C and shorter term electrochemically monitored experiments (rest potential, impedance, anodic current) generally conducted at 22 0 C. The pH9.2 solution effectively inhibited the initiation of crevice and intergranular corrosion in the presence of low levels of chloride and sulphate, whereas the pH7 solution did not always do so. However, the pH9.2 solution, dosed with 40 gm -3 chloride, failed to suppress fully crevice corrosion initiated in unborated 40 gm -3 chloride solution at 22 0 C. Fluoride is not deleterious at low levels ∼ 10 gm -3 in the borate solutions. The significant improvement in corrosion control demonstrated for the change from pH7 to pH9.2 borate solution on laboratory sensitised brace samples should ideally be confirmed using complete irradiated AGR fuel elements. (U.K.)

Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control

KAUST Repository

Sun, Liangfeng; Choi, Joshua J.; Stachnik, David; Bartnik, Adam C.; Hyun, Byung-Ryool; Malliaras, George G.; Hanrath, Tobias; Wise, Frank W.

2012-01-01

Infrared light-emitting diodes are currently fabricated from direct-gap semiconductors using epitaxy, which makes them expensive and difficult to integrate with other materials. Light-emitting diodes based on colloidal semiconductor quantum dots, on the other hand, can be solution-processed at low cost, and can be directly integrated with silicon. However, so far, exciton dissociation and recombination have not been well controlled in these devices, and this has limited their performance. Here, by tuning the distance between adjacent PbS quantum dots, we fabricate thin-film quantum-dot light-emitting diodes that operate at infrared wavelengths with radiances (6.4 W sr '1 m '2) eight times higher and external quantum efficiencies (2.0%) two times higher than the highest values previously reported. The distance between adjacent dots is tuned over a range of 1.3 nm by varying the lengths of the linker molecules from three to eight CH 2 groups, which allows us to achieve the optimum balance between charge injection and radiative exciton recombination. The electroluminescent powers of the best devices are comparable to those produced by commercial InGaAsP light-emitting diodes. By varying the size of the quantum dots, we can tune the emission wavelengths between 800 and 1,850 nm.© 2012 Macmillan Publishers Limited.

Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control.

Science.gov (United States)

Sun, Liangfeng; Choi, Joshua J; Stachnik, David; Bartnik, Adam C; Hyun, Byung-Ryool; Malliaras, George G; Hanrath, Tobias; Wise, Frank W

2012-05-06

Infrared light-emitting diodes are currently fabricated from direct-gap semiconductors using epitaxy, which makes them expensive and difficult to integrate with other materials. Light-emitting diodes based on colloidal semiconductor quantum dots, on the other hand, can be solution-processed at low cost, and can be directly integrated with silicon. However, so far, exciton dissociation and recombination have not been well controlled in these devices, and this has limited their performance. Here, by tuning the distance between adjacent PbS quantum dots, we fabricate thin-film quantum-dot light-emitting diodes that operate at infrared wavelengths with radiances (6.4 W sr(-1) m(-2)) eight times higher and external quantum efficiencies (2.0%) two times higher than the highest values previously reported. The distance between adjacent dots is tuned over a range of 1.3 nm by varying the lengths of the linker molecules from three to eight CH(2) groups, which allows us to achieve the optimum balance between charge injection and radiative exciton recombination. The electroluminescent powers of the best devices are comparable to those produced by commercial InGaAsP light-emitting diodes. By varying the size of the quantum dots, we can tune the emission wavelengths between 800 and 1,850 nm.

Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control

KAUST Repository

Sun, Liangfeng

2012-05-06

Infrared light-emitting diodes are currently fabricated from direct-gap semiconductors using epitaxy, which makes them expensive and difficult to integrate with other materials. Light-emitting diodes based on colloidal semiconductor quantum dots, on the other hand, can be solution-processed at low cost, and can be directly integrated with silicon. However, so far, exciton dissociation and recombination have not been well controlled in these devices, and this has limited their performance. Here, by tuning the distance between adjacent PbS quantum dots, we fabricate thin-film quantum-dot light-emitting diodes that operate at infrared wavelengths with radiances (6.4 W sr \\'1 m \\'2) eight times higher and external quantum efficiencies (2.0%) two times higher than the highest values previously reported. The distance between adjacent dots is tuned over a range of 1.3 nm by varying the lengths of the linker molecules from three to eight CH 2 groups, which allows us to achieve the optimum balance between charge injection and radiative exciton recombination. The electroluminescent powers of the best devices are comparable to those produced by commercial InGaAsP light-emitting diodes. By varying the size of the quantum dots, we can tune the emission wavelengths between 800 and 1,850 nm.© 2012 Macmillan Publishers Limited.

Dot gain compensation in the blue noise mask

Science.gov (United States)

Yao, Meng; Parker, Kevin J.

1995-04-01

Frequency modulated (FM) halftoning or 'stochastic screening,' has attracted a great deal of attention in the printing industry in recent years. It has several advantages over conventional halftoning. But one serious problem that arises in FM halftoning is dot gain. One approach to stochastic screening uses a specially constructed halftone screen, the blue noise mask (BNM), to produce an unstructured and visually appealing pattern of halftone dots at any gray level. In this paper, we will present methods to correct dot gain with the BNM. Dot gain is related to the area-to-perimeter ration of printed spots. We can exploit this feature in different ways. At a medium level, a B>NM pattern will have 'connected' as well as 'isolated' dots. Normally, as we build down BNM patterns to lower levels, a specific number of white dots will be replace by black dots. Since connected white dots are more likely to be picked than isolated white dots, this will results in substantial dot gain because of the increasing number of isolated white dots. We show that it is possible to constrain the process of constructing a BNM such that isolated dots are preferentially removes, thus significantly reducing dot gain in a BNM.

Electron correlations in quantum dots

International Nuclear Information System (INIS)

Tipton, Denver Leonard John

2001-01-01

Quantum dot structures confine electrons in a small region of space. Some properties of semiconductor quantum dots, such as the discrete energy levels and shell filling effects visible in addition spectra, have analogies to those of atoms and indeed dots are sometimes referred to as 'artificial atoms'. However, atoms and dots show some fundamental differences due to electron correlations. For real atoms, the kinetic energy of electrons dominates over their mutual Coulomb repulsion energy and for this reason the independent electron approximation works well. For quantum dots the confining potential may be shallower than that of real atoms leading to lower electron densities and a dominance of mutual Coulomb repulsion over kinetic energy. In this strongly correlated regime the independent electron picture leads to qualitatively incorrect results. This thesis concentrates on few-electron quantum dots in the strongly correlated regime both for quasi-one-dimensional and two-dimensional dots in a square confining potential. In this so-called 'Wigner' regime the ground-state electronic charge density is localised near positions of classical electrostatic minima and the interacting electronic spectrum consists of well separated spin multiplets. In the strongly correlated regime the structure of low-energy multiplets is explained by mapping onto lattice models with extended-Hubbard and Heisenberg effective Hamiltonians. The parameters for these effective models are calculated within a Hartree approximation and are shown to reproduce well the exact results obtained by numerical diagonalisation of the full interacting Hamiltonian. Comparison is made between square dots and quantum rings with full rotational symmetry. In the very low-density regime, direct diagonalisation becomes impractical due to excessive computer time for convergence. In this regime a numerical renormalisation group method is applied to one-dimensional dots, enabling effective spin-interactions to be

Magnon-driven quantum dot refrigerators

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuan; Huang, Chuankun; Liao, Tianjun; Chen, Jincan, E-mail: jcchen@xmu.edu.cn

2015-12-18

Highlights: • A three-terminal quantum dot refrigerator is proposed. • The effects of magnetic field, applied voltage, and polarization are considered. • The region that the system can work as a refrigerator is determined. • Two different magnon-driven quantum dot refrigerators are compared. - Abstract: A new model of refrigerator consisting of a spin-splitting quantum dot coupled with two ferromagnetic reservoirs and a ferromagnetic insulator is proposed. The rate equation is used to calculate the occupation probabilities of the quantum dot. The expressions of the electron and magnon currents are obtained. The region that the system can work in as a refrigerator is determined. The cooling power and coefficient of performance (COP) of the refrigerator are derived. The influences of the magnetic field, applied voltage, and polarization of two leads on the performance are discussed. The performances of two different magnon-driven quantum dot refrigerators are compared.

Multi-Excitonic Quantum Dot Molecules

Science.gov (United States)

Scheibner, M.; Stinaff, E. A.; Doty, M. F.; Ware, M. E.; Bracker, A. S.; Gammon, D.; Ponomarev, I. V.; Reinecke, T. L.; Korenev, V. L.

2006-03-01

With the ability to create coupled pairs of quantum dots, the next step towards the realization of semiconductor based quantum information processing devices can be taken. However, so far little knowledge has been gained on these artificial molecules. Our photoluminescence experiments on single InAs/GaAs quantum dot molecules provide the systematics of coupled quantum dots by delineating the spectroscopic features of several key charge configurations in such quantum systems, including X, X^+,X^2+, XX, XX^+ (with X being the neutral exciton). We extract general rules which determine the formation of molecular states of coupled quantum dots. These include the fact that quantum dot molecules provide the possibility to realize various spin configurations and to switch the electron hole exchange interaction on and off by shifting charges inside the molecule. This knowledge will be valuable in developing implementations for quantum information processing.

Evaluation of seismic behavior of a braced tubular steel structure by pseudodynamic testing

International Nuclear Information System (INIS)

Shiny, P.B.; Javadian-Gilani, A.S.; Mahin, S.A.

1984-01-01

The inelastic seismic behavior of an X-braced, tubular steel frame is studied experimentally by means of pseudodynamic testing. The pseudodynamic method, which utilizes a numerical algorithm in the on-line computer control of a test specimen, can realistically simulate the seismic response of a structural model. This paper presents a brief outline of the experimental procedure and the results of the tubular frame tests, including the global responses, the inelastic energy-dissipation capabilities, and the failure mechanism of the frame at various excitation levels. Correlation of these results with previous experimental studies illustrates the feasibility and accuracy of the new test method

78 FR 48868 - Proposed Cercla Administrative Cost Recovery Settlement; MassDOT, MassDOT Route 1 Right-of-Way...

Science.gov (United States)

2013-08-12

... Settlement; MassDOT, MassDOT Route 1 Right-of-Way Site, Chelsea, MA AGENCY: Environmental Protection Agency... (``CERCLA''), 42 U.S.C. 9622(h)(1), concerning the MassDOT Route 1 Right-of-Way Site in Chelsea... (OES04-3), Boston, MA 02109-3912 (Telephone No. 617-918-1886) and should refer to: In re: MassDOT Route 1...

Physical, chemical and antimicrobial evaluation of a composite material containing quaternary ammonium salt for braces cementation

International Nuclear Information System (INIS)

Sugii, Mari Miura; Ferreira, Fábio Augusto de Souza; Müller, Karina Cogo; Lima, Debora Alves Nunes Leite; Groppo, Francisco Carlos; Imasato, Hidetake; Rodrigues-Filho, Ubirajara Pereira

2017-01-01

The antibiofilm effect of iodide quaternary ammonium methacryloxy silicate (IQAMS) in Transbond XT Light Cure Adhesive resin used for braces cementation was evaluated. Fourier Transform Infrared (FTIR) spectroscopy confirmed IQAMS formation and Scanning Electron Microscopy coupled to Energy-Dispersive X-ray Spectroscopy (SEM-EDS) revealed that as coating, the quaternary ammonium groups from IQAMS were homogeneously dispersed throughout the surface. When incorporated, the composite material presented homogeneous dispersion throughout the resin. Assays with Streptococcus mutans demonstrated enhanced antibiofilm effect for the IQAMS coated resin, with much lower colony-forming units (CFU), in comparison to incorporated IQAMS. Such a difference was assigned to low availability of quaternary ammonium groups at the surface of resin when IQAMS was incorporated, hindering its antibiofilm effect. Additionally, the incorporation of IQAMS led to slight decrease in ultimate bond strength (UBS) and shear bond strength (SBS), in comparison to the neat commercial resin. Thus, the synthesized IQAMS displays great potential as antibiofilm coating or sealant to prevent oral infections in brackets during orthodontic treatment. - Highlights: • Synthesis of ORMOSIL-based material with antibiofilm activity is performed. • Antibiofilm activity of the ORMOSIL-based material on commercial available resin for braces cementation is evaluated. • Antibiofilm ORMOSIL-based coating with potential application as varnish or sealant in orthodontic appliances is presented.

Physical, chemical and antimicrobial evaluation of a composite material containing quaternary ammonium salt for braces cementation

Energy Technology Data Exchange (ETDEWEB)

Sugii, Mari Miura [Departamento de Odontologia Restaurativa, Faculdade de Odontologia de Piracicaba – Universidade de Campinas, Piracicaba, SP 13414-903 (Brazil); Ferreira, Fábio Augusto de Souza, E-mail: ferreira.fabio.a.s@gmail.com [Grupo de Química de Materiais Híbridos e Inorgânicos, Instituto de Química de São Carlos – Universidade de São Paulo, São Carlos, SP 13563-120 (Brazil); Müller, Karina Cogo [Departamento de Ciências Fisiológicas, Área de Farmacologia, Anestesiologia e Terapeutica, Faculdade de Odontologia de Piracicaba – Universidade de Campinas, Piracicaba, SP 13414-903 (Brazil); Lima, Debora Alves Nunes Leite [Departamento de Odontologia Restaurativa, Faculdade de Odontologia de Piracicaba – Universidade de Campinas, Piracicaba, SP 13414-903 (Brazil); Groppo, Francisco Carlos [Departamento de Ciências Fisiológicas, Área de Farmacologia, Anestesiologia e Terapeutica, Faculdade de Odontologia de Piracicaba – Universidade de Campinas, Piracicaba, SP 13414-903 (Brazil); Imasato, Hidetake; Rodrigues-Filho, Ubirajara Pereira [Grupo de Química de Materiais Híbridos e Inorgânicos, Instituto de Química de São Carlos – Universidade de São Paulo, São Carlos, SP 13563-120 (Brazil); and others

2017-04-01

The antibiofilm effect of iodide quaternary ammonium methacryloxy silicate (IQAMS) in Transbond XT Light Cure Adhesive resin used for braces cementation was evaluated. Fourier Transform Infrared (FTIR) spectroscopy confirmed IQAMS formation and Scanning Electron Microscopy coupled to Energy-Dispersive X-ray Spectroscopy (SEM-EDS) revealed that as coating, the quaternary ammonium groups from IQAMS were homogeneously dispersed throughout the surface. When incorporated, the composite material presented homogeneous dispersion throughout the resin. Assays with Streptococcus mutans demonstrated enhanced antibiofilm effect for the IQAMS coated resin, with much lower colony-forming units (CFU), in comparison to incorporated IQAMS. Such a difference was assigned to low availability of quaternary ammonium groups at the surface of resin when IQAMS was incorporated, hindering its antibiofilm effect. Additionally, the incorporation of IQAMS led to slight decrease in ultimate bond strength (UBS) and shear bond strength (SBS), in comparison to the neat commercial resin. Thus, the synthesized IQAMS displays great potential as antibiofilm coating or sealant to prevent oral infections in brackets during orthodontic treatment. - Highlights: • Synthesis of ORMOSIL-based material with antibiofilm activity is performed. • Antibiofilm activity of the ORMOSIL-based material on commercial available resin for braces cementation is evaluated. • Antibiofilm ORMOSIL-based coating with potential application as varnish or sealant in orthodontic appliances is presented.

Seismic Retrofit of Reinforced Concrete Frame Buildings with Hysteretic Bracing Systems: Design Procedure and Behaviour Factor

Directory of Open Access Journals (Sweden)

Antonio Di Cesare

2017-01-01

Full Text Available This paper presents a design procedure to evaluate the mechanical characteristics of hysteretic Energy Dissipation Bracing (EDB systems for seismic retrofitting of existing reinforced concrete framed buildings. The proposed procedure, aiming at controlling the maximum interstorey drifts, imposes a maximum top displacement as function of the seismic demand and, if needed, regularizes the stiffness and strength of the building along its elevation. In order to explain the application of the proposed procedure and its capacity to involve most of the devices in the energy dissipation with similar level of ductility demand, a simple benchmark structure has been studied and nonlinear dynamic analyses have been performed. A further goal of this work is to propose a simplified approach for designing dissipating systems based on linear analysis with the application of a suitable behaviour factor, in order to achieve a widespread adoption of the passive control techniques. At this goal, the increasing of the structural performances due to the addition of an EDB system designed with the above-mentioned procedure has been estimated considering one thousand case studies designed with different combinations of the main design parameters. An analytical formulation of the behaviour factor for braced buildings has been proposed.

Synthesis and evaluation of 1-[l brace]1-[5-(2'-[[sup 18]F]fluoroethyl)-2-thienyl]cyclohexyl[r brace]piperidine as a potential in vivo radioligand for the NMDA receptor-channel complex. [N-methyl-D-aspartate receptor

Energy Technology Data Exchange (ETDEWEB)

Orita, Kazuhiro; Sasaki, Shigeki; Maeda, Minoru [Kyushu Univ., Fukuoka (Japan). Faculty of Pharmaceutical Sciences; Hashimoto, Atsushi; Nishikawa, Toru [National Inst. of Neuroscience, Tokyo (Japan); Yugami, Tomoko; Umezu, Kohei [Mitsubishi Kasei Corp., Yokohama (Japan). Research Center

1993-10-01

1-[l brace]1-[5-(2'-[[sup 18]F]Fluoroethyl)-2-thienyl]cyclohexyl[r brace]piperidine ([sup 18]FE-TCP) was prepared a fluorine-substituted analogue of the potent NMDA receptor channel blocker, 1-[1-(2-thienyl)cyclohexyl]piperidine (TCP), by the mesylate displacement with [[sup 18]F]fluoride ion with isolated radiochemical yields of 6-12%, and the synthesis time including a two step HPLC purification was 120 min. The regional distribution in rat brain after i.v. injection of [sup 18]FE-TCP was heterogeneous and similar to the known distribution of phencyclidine recognition sites, with hippocampus-cerebellum, striatum-cerebellum and cerebral cortex-cerebellum concentration ratios of 2.08, 1.7 and 1.54, respectively, 15 min post-injection. Furthermore, this localized regional cerebral distribution was blocked by co-injection with the unlabelled FE-TCP or pretreatment with cis-2-hydroxymethyl-r-1-(N-piperidyl)-1-(2-thienyl)cyclohexane, with the greatest reductions seen in the hippocampus followed by the striatum and cerebral cortex. However, relatively low receptor binding affinity and high non-specific binding due to its high lipophilicity suggest that [sup 18]FE-TCP may not be a suitable radioligand for in vivo PET investigations of the NMDA receptor-channel complex. (Author).

Biocompatible Quantum Dots for Biological Applications

Science.gov (United States)

Rosenthal, Sandra J.; Chang, Jerry C.; Kovtun, Oleg; McBride, James R.; Tomlinson, Ian D.

2011-01-01

Semiconductor quantum dots are quickly becoming a critical diagnostic tool for discerning cellular function at the molecular level. Their high brightness, long-lasting, sizetunable, and narrow luminescence set them apart from conventional fluorescence dyes. Quantum dots are being developed for a variety of biologically oriented applications, including fluorescent assays for drug discovery, disease detection, single protein tracking, and intracellular reporting. This review introduces the science behind quantum dots and describes how they are made biologically compatible. Several applications are also included, illustrating strategies toward target specificity, and are followed by a discussion on the limitations of quantum dot approaches. The article is concluded with a look at the future direction of quantum dots. PMID:21276935

Quantum measurement of coherent tunneling between quantum dots

International Nuclear Information System (INIS)

Wiseman, H. M.; Utami, Dian Wahyu; Sun, He Bi; Milburn, G. J.; Kane, B. E.; Dzurak, A.; Clark, R. G.

2001-01-01

We describe the conditional and unconditional dynamics of two coupled quantum dots when one dot is subjected to a measurement of its occupation number by coupling it to a third readout dot via the Coulomb interaction. The readout dot is coupled to source and drain leads under weak bias, and a tunnel current flows through a single bound state when energetically allowed. The occupation of the quantum dot near the readout dot shifts the bound state of the readout dot from a low conducting state to a high conducting state. The measurement is made by continuously monitoring the tunnel current through the readout dot. We show that there is a difference between the time scale for the measurement-induced decoherence between the localized states of the dots, and the time scale on which the system becomes localized due to the measurement

A study on socio-demographic profile and feasibility of DOTS provider registered under RNTCP in Varanasi district Uttar Pradesh

Directory of Open Access Journals (Sweden)

Mohd. Afzalul Haque

2014-03-01

Full Text Available Introduction: Tuberculosis is a major chronic disorder affecting the larger population more than any other disease in the country. DOTS was introduced in India in 1993 as part of the Revised National Tuberculosis Programme (RNTCP following a review of India’s National Tuberculosis Programme (NTP a year earlier (1 .Patient satisfaction is an important parameter for assessing the quality of patient care services. There is need to assess the health care provider regarding the consumer satisfaction as often as possible, this paper summarizes our experience about role of DOTS provider in the management of TB patient in rural population of Varanasi districts Utter Pradesh. Objective: (1 To assess the perception of registered tuberculosis patients regarding DOTS provider for the treatment of tuberculosis. (2 To assess the accessibility, acceptability & availability of community DOTS provider. Design: A longitudinal study. Setting: Three microscopic centre of Cholapur Tuberculosis unit of Varanasi districts. Methods: Registered patients were interviewed twice: once in the beginning and another at the completion of the treatment or after the permanent discontinuation of the treatment. Patients were interviewed for their socio-demographic profiles, opinion about DOTS and its providers. Side effects experienced and action taken etc. Data was collected on a semi-structured, pre-tested questionnaire. DOTS providers were interviewed and treatment cards analyzed for any interruption of treatment and action taken. Data was collected from 1st June 2004 to 31th June 2005 till the completion of the regimen. Results: Majority of DOTS providers were young males (82.7% of 26 years to 40 years, while the representation of females was only 5 (17.3%. Almost more than 80% of the patients started their treatment within 1-10 days. For majority of cases (83% the distance of DOTS provider from patient’s house was within 1 km. Mean time spent to go to DOTS provider was 27

Metamorphic quantum dots: Quite different nanostructures

International Nuclear Information System (INIS)

Seravalli, L.; Frigeri, P.; Nasi, L.; Trevisi, G.; Bocchi, C.

2010-01-01

In this work, we present a study of InAs quantum dots deposited on InGaAs metamorphic buffers by molecular beam epitaxy. By comparing morphological, structural, and optical properties of such nanostructures with those of InAs/GaAs quantum dot ones, we were able to evidence characteristics that are typical of metamorphic InAs/InGaAs structures. The more relevant are: the cross-hatched InGaAs surface overgrown by dots, the change in critical coverages for island nucleation and ripening, the nucleation of new defects in the capping layers, and the redshift in the emission energy. The discussion on experimental results allowed us to conclude that metamorphic InAs/InGaAs quantum dots are rather different nanostructures, where attention must be put to some issues not present in InAs/GaAs structures, namely, buffer-related defects, surface morphology, different dislocation mobility, and stacking fault energies. On the other hand, we show that metamorphic quantum dot nanostructures can provide new possibilities of tailoring various properties, such as dot positioning and emission energy, that could be very useful for innovative dot-based devices.

Templated self-assembly of SiGe quantum dots

Energy Technology Data Exchange (ETDEWEB)

Dais, Christian

2009-08-19

This PhD thesis reports on the fabrication and characterization of exact aligned SiGe quantum dot structures. In general, SiGe quantum dots which nucleate via the Stranski-Krastanov growth mode exhibit broad size dispersion and nucleate randomly on the surface. However, to tap the full potential of SiGe quantum dots it is necessary to control the positioning and size of the dots on a nanometer length, e.g. for electronically addressing of individual dots. This can be realized by so-called templated self-assembly, which combines top-down lithography with bottom-up selfassembly. In this process the lithographically defined pits serve as pre-defined nucleation points for the epitaxially grown quantum dots. In this thesis, extreme ultraviolet interference lithography at a wavelength of e=13.4 nm is employed for prepatterning of the Si substrates. This technique allows the precise and fast fabrication of high-resolution templates with a high degree of reproducibility. The subsequent epitaxial deposition is either performed by molecular beam epitaxy or low-pressure chemical vapour deposition. It is shown that the dot nucleation on pre-patterned substrates depends strongly on the lithography parameters, e.g. size and periodicity of the pits, as well as on the epitaxy parameters, e.g. growth temperature or material coverage. The interrelations are carefully analyzed by means of scanning force microscopy, transmission electron microscopy and X-ray diffraction measurements. Provided that correct template and overgrowth parameters are chosen, perfectly aligned and uniform SiGe quantum dot arrays of different period, size as well as symmetry are created. In particular, the quantum dot arrays with the so far smallest period (35 nm) and smallest size dispersion are fabricated in this thesis. Furthermore, the strain fields of the underlying quantum dots allow the fabrication of vertically aligned quantum dot stacks. Combining lateral and vertical dot alignment results in three

Effect of bracing and other conservative interventions in the treatment of idiopathic scoliosis in adolescents : A systematic review of clinical trials

NARCIS (Netherlands)

Lenssinck, MLB; Frijlink, AC; Berger, MY; Bierma-Zeinstra, SMA; Verkerk, K; Verhagen, AP

2005-01-01

Background and Purpose. Many conservative treatments are available for adolescents with idiopathic scoliosis, but the evidence for their accepted use is still unclear. The purpose of this study was to evaluate the effectiveness of braces and other conservative treatments of idiopathic scoliosis in

Quantum dots: Rethinking the electronics

Energy Technology Data Exchange (ETDEWEB)

Bishnoi, Dimple [Department of Physics, S. S. Jain Subodh PG College, Jaipur, Rajasthan Pin-302004 (India)

2016-05-06

In this paper, we demonstrate theoretically that the Quantum dots are quite interesting for the electronics industry. Semiconductor quantum dots (QDs) are nanometer-scale crystals, which have unique photo physical, quantum electrical properties, size-dependent optical properties, There small size means that electrons do not have to travel as far as with larger particles, thus electronic devices can operate faster. Cheaper than modern commercial solar cells while making use of a wider variety of photon energies, including “waste heat” from the sun’s energy. Quantum dots can be used in tandem cells, which are multi junction photovoltaic cells or in the intermediate band setup. PbSe (lead selenide) is commonly used in quantum dot solar cells.

The electronic properties of semiconductor quantum dots

International Nuclear Information System (INIS)

Barker, J.A.

2000-10-01

This work is an investigation into the electronic behaviour of semiconductor quantum dots, particularly self-assembled quantum dot arrays. Processor-efficient models are developed to describe the electronic structure of dots, deriving analytic formulae for the strain tensor, piezoelectric distribution and diffusion- induced evolution of the confinement potential, for dots of arbitrary initial shape and composition profile. These models are then applied to experimental data. Transitions due to individual quantum dots have a narrow linewidth as a result of their discrete density of states. By contrast, quantum dot arrays exhibit inhomogeneous broadening which is generally attributed to size variations between the individual dots in the ensemble. Interpreting the results of double resonance spectroscopy, it is seen that variation in the indium composition of the nominally InAs dots is also present. This result also explains the otherwise confusing relationship between the spread in the ground-state and excited-state transition energies. Careful analysis shows that, in addition to the variations in size and composition, some other as yet unidentified broadening mechanism must also be present. The influence of rapid thermal annealing on dot electronic structure is also considered, finding that the experimentally observed blue-shift and narrowing of the photoluminescence linewidth may both be explained in terms of normal In/Ga interdiffusion. InAs/GaAs self-assembled quantum dots are commonly assumed to have a pyramidal geometry, so that we would expect the energy separation of the ground-state electron and hole levels in the dot to be largest at a positive applied field. This should also be the case for any dot of uniform composition whose shape tapers inwards from base to top, counter to the results of experimental Stark-shift spectroscopy which show a peak transition energy at a negative applied field. It is demonstrated that this inversion of the ground state

The DotA protein from Legionella pneumophila is secreted by a novel process that requires the Dot/Icm transporter

OpenAIRE

Nagai, Hiroki; Roy, Craig R.

2001-01-01

Legionella pneumophila requires the dot/icm genes to create an organelle inside eukaryotic host cells that will support bacterial replication. The dot/icm genes are predicted to encode a type IV-related secretion apparatus. However, no proteins have been identified that require the dot/icm genes for secretion. In this study we show that the DotA protein, which was previously found to be a polytopic membrane protein, is secreted by the Dot/Icm transporter into culture supernatants. Secreted Do...

Design of quaternary logic circuit using quantum dot gate-quantum dot channel FET (QDG-QDCFET)

Science.gov (United States)

Karmakar, Supriya

2014-10-01

This paper presents the implementation of quaternary logic circuits based on quantum dot gate-quantum dot channel field effect transistor (QDG-QDCFET). The super lattice structure in the quantum dot channel region of QDG-QDCFET and the electron tunnelling from inversion channel to the quantum dot layer in the gate region of a QDG-QDCFET change the threshold voltage of this device which produces two intermediate states between its ON and OFF states. This property of QDG-QDCFET is used to implement multi-valued logic for future multi-valued logic circuit. This paper presents the design of basic quaternary logic operation such as inverter, AND and OR operation based on QDG-QDCFET.

Treatment of the Developmental Dysplasia of the Hip with an Abduction Brace in Children up to 6 Months Old

Directory of Open Access Journals (Sweden)

Raphaël Wahlen

2015-01-01

Full Text Available Introduction. Use of Pavlik harness for the treatment of DDH can be complicated for parents. Any misuse or failure in the adjustments may lead to significant complications. An abduction brace was introduced in our institution, as it was thought to be easier to use. Aim. We assess the results for the treatment of DDH using our abduction brace in children of 0–6 months old and compare these results with data on treatments using the Pavlik harness. Method. Retrospective analysis of patients with DDH from 0 to 6 months old at diagnosis, performed from 2004 to 2009. Outcomes were rates of reduction of the hip and avascular necrosis of the femoral head (AVN. Follow-up was at one year and up to 4 years old. Results. Hip reduction was successful in 28 of 33 patients (85%, with no AVN. Conclusion. Our results in terms of hip reduction rate and AVN rate are similar to those found in literature assessing Pavlik harness use, with a simpler and comfortable treatment procedure.

Semiconductor quantum-dot lasers and amplifiers

DEFF Research Database (Denmark)

Hvam, Jørn Märcher; Borri, Paola; Ledentsov, N. N.

2002-01-01

-power surface emitting VCSELs. We investigated the ultrafast dynamics of quantum-dot semiconductor optical amplifiers. The dephasing time at room temperature of the ground-state transition in semiconductor quantum dots is around 250 fs in an unbiased amplifier, decreasing to below 50 fs when the amplifier...... is biased to positive net gain. We have further measured gain recovery times in quantum dot amplifiers that are significantly lower than in bulk and quantum-well semiconductor optical amplifiers. This is promising for future demonstration of quantum dot devices with high modulation bandwidth...

Transport properties of a Kondo dot with a larger side-coupled noninteracting quantum dot

International Nuclear Information System (INIS)

Liu, Y S; Fan, X H; Xia, Y J; Yang, X F

2008-01-01

We investigate theoretically linear and nonlinear quantum transport through a smaller quantum dot in a Kondo regime connected to two leads in the presence of a larger side-coupled noninteracting quantum dot, without tunneling coupling to the leads. To do this we employ the slave boson mean field theory with the help of the Keldysh Green's function at zero temperature. The numerical results show that the Kondo conductance peak may develop multiple resonance peaks and multiple zero points in the conductance spectrum owing to constructive and destructive quantum interference effects when the energy levels of the large side-coupled noninteracting dot are located in the vicinity of the Fermi level in the leads. As the coupling strength between two quantum dots increases, the tunneling current through the quantum device as a function of gate voltage applied across the two leads is suppressed. The spin-dependent transport properties of two parallel coupled quantum dots connected to two ferromagnetic leads are also investigated. The numerical results show that, for the parallel configuration, the spin current or linear spin differential conductance are enhanced when the polarization strength in the two leads is increased

Sol-Gel Chemistry for Carbon Dots.

Science.gov (United States)

Malfatti, Luca; Innocenzi, Plinio

2018-03-14

Carbon dots are an emerging class of carbon-based nanostructures produced by low-cost raw materials which exhibit a widely-tunable photoluminescence and a high quantum yield. The potential of these nanomaterials as a substitute of semiconductor quantum dots in optoelectronics and biomedicine is very high, however they need a customized chemistry to be integrated in host-guest systems or functionalized in core-shell structures. This review is focused on recent advances of the sol-gel chemistry applied to the C-dots technology. The surface modification, the fine tailoring of the chemical composition and the embedding into a complex nanostructured material are the main targets of combining sol-gel processing with C-dots chemistry. In addition, the synergistic effect of the sol-gel precursor combined with the C-dots contribute to modify the intrinsic chemo-physical properties of the dots, empowering the emission efficiency or enabling the tuning of the photoluminescence over a wide range of the visible spectrum. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Large quantum dots with small oscillator strength

DEFF Research Database (Denmark)

Stobbe, Søren; Schlereth, T.W.; Höfling, S.

2010-01-01

We have measured the oscillator strength and quantum efficiency of excitons confined in large InGaAs quantum dots by recording the spontaneous emission decay rate while systematically varying the distance between the quantum dots and a semiconductor-air interface. The size of the quantum dots...... is measured by in-plane transmission electron microscopy and we find average in-plane diameters of 40 nm. We have calculated the oscillator strength of excitons of that size assuming a quantum-dot confinement given by a parabolic in-plane potential and a hard-wall vertical potential and predict a very large...... intermixing inside the quantum dots....

Thermally oxidized formation of new Ge dots over as-grown Ge dots in the Si capping layer

International Nuclear Information System (INIS)

Nie Tianxiao; Lin Jinhui; Shao Yuanmin; Wu Yueqin; Yang Xinju; Fan Yongliang; Jiang Zuimin; Chen Zhigang; Zou Jin

2011-01-01

A Si-capped Ge quantum dot sample was self-assembly grown via Stranski-Krastanov mode in a molecular beam epitaxy system with the Si capping layer deposited at 300 deg. C. After annealing the sample in an oxygen atmosphere at 1000 deg. C, a structure, namely two layers of quantum dots, was formed with the newly formed Ge-rich quantum dots embedded in the oxidized matrix with the position accurately located upon the as-grown quantum dots. It has been found that the formation of such nanostructures strongly depends upon the growth temperature and oxygen atmosphere. A growth mechanism was proposed to explain the formation of the nanostructure based on the Ge diffusion from the as-grown quantum dots, Ge segregation from the growing oxide, and subsequent migration/agglomeration.

Octacyanoniobate(IV)-based molecular magnets revealing 3D long-range order

Energy Technology Data Exchange (ETDEWEB)

Pelka, R; Balanda, M [Institute of Physics PAN, Radzikowskiego 152, 31-342, Krakow (Poland); Pinkowicz, D; Drath, O; Nitek, W; Sieklucka, B [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Rams, M; Majcher, A, E-mail: robert.pelka@ifj.edu.pl [Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland)

2011-07-06

Isostructural series of chemical formula {l_brace}[M{sup II}(pirazol){sub 4}]{sub 2}[Nb{sup IV}(CN){sub 8}]{center_dot} 4H{sub 2}O{r_brace}{sub n} (M{sup II} = Mn (1), Fe (2), Co (3), Ni (4)) has been obtained by the self-assembly technique. Its unique crystallographic structure consists in the formation of a 3D extended network of magnetic centers braced by geometrically identical cyanido bridges. Magnetic measurements reveal the transitions to the 3D order at temperatures 23.7, 8.3, 5.9, 13.4 K for 1, 2, 3, and 4, respectively. The character of order is demonstrated to be ferrimagnetic for 1 and 2 and ferromagnetic for 3 and 4. The mean-field approach is used to determine the corresponding exchange coupling constants. The observed interactions are discussed within the magnetic orbital model.

Eccentric exercises for the management of tendinopathy of the main body of the Achilles tendon with or without the AirHeel Brace. A randomized controlled trial. A: effects on pain and microcirculation.

Science.gov (United States)

Knobloch, Karsten; Schreibmueller, Louisa; Longo, Umile Giuseppe; Vogt, Peter M

2008-01-01

To compare eccentric training and the combination of eccentric training with the AirHeel Brace for the management of tendinopathy of the main body of the Achilles tendon. We recruited 116 subjects with unilateral tendinopathy of the main body of the Achilles tendon, who were randomized in two groups. Group A performed a regimen of daily eccentric training associated with the AirHeel Brace (Donjoy Orthopedics, Vista, CA, USA). Group B performed the same eccentric training without the AirHeel Brace. Tendon microcirculatory mapping was performed using combined Laser-Doppler and spectrophotometry. Pre- and post-operative FAOS score and VAS score were used to evaluate the patients. The FAOS score and the VAS score showed significant improvements from pre-operative to post-operative values in both groups (A 5.1 +/- 2 vs. 2.9 +/- 2.4, 43% reduction and B: 5.4 +/- 2.1 vs. 3.6 +/- 2.4, 33% reduction, both p = 0.0001). There were no statistically significant differences in FAOS score and VAS score when comparing the two groups after the end of the intervention. In Group A, tendon oxygen saturation in the main body of the Achilles tendon showed significant increase from pre- to post-management values (68 +/- 12 vs.74 +/- 8%, p = 0.003). Post-capillary venous filling pressures showed significant reduction from pre- to post-intervention values. Eccentric training, associated or not with the AirHeel Brace, produces the same effect in patients with tendinopathy of the main body of the Achilles tendon. The combination of eccentric training with the AirHeel Brace can optimize tendon microcirculation, but these micro-circulator advantages do not translate into superior clinical performance when compared with eccentric training alone.

Optical properties of quantum-dot-doped liquid scintillators

International Nuclear Information System (INIS)

Aberle, C; Winslow, L; Li, J J; Weiss, S

2013-01-01

Semiconductor nanoparticles (quantum dots) were studied in the context of liquid scintillator development for upcoming neutrino experiments. The unique optical and chemical properties of quantum dots are particularly promising for the use in neutrinoless double-beta decay experiments. Liquid scintillators for large scale neutrino detectors have to meet specific requirements which are reviewed, highlighting the peculiarities of quantum-dot-doping. In this paper, we report results on laboratory-scale measurements of the attenuation length and the fluorescence properties of three commercial quantum dot samples. The results include absorbance and emission stability measurements, improvement in transparency due to filtering of the quantum dot samples, precipitation tests to isolate the quantum dots from solution and energy transfer studies with quantum dots and the fluorophore PPO

Optical Signatures of Coupled Quantum Dots

Science.gov (United States)

Stinaff, E. A.; Scheibner, M.; Bracker, A. S.; Ponomarev, I. V.; Korenev, V. L.; Ware, M. E.; Doty, M. F.; Reinecke, T. L.; Gammon, D.

2006-02-01

An asymmetric pair of coupled InAs quantum dots is tuned into resonance by applying an electric field so that a single hole forms a coherent molecular wave function. The optical spectrum shows a rich pattern of level anticrossings and crossings that can be understood as a superposition of charge and spin configurations of the two dots. Coulomb interactions shift the molecular resonance of the optically excited state (charged exciton) with respect to the ground state (single charge), enabling light-induced coupling of the quantum dots. This result demonstrates the possibility of optically coupling quantum dots for application in quantum information processing.

Investigation of defects in electron-irradiated diamond of the type Ia by positron annihilation

International Nuclear Information System (INIS)

Novikov, N.V.; Ositinskaya, T.D.; Mikhalenkov, V.S.; Chernyashevskij, A.V.; Shakhovtsov, V.I.; AN Ukrainskoj SSR, Kiev; AN Ukrainskoj SSR, Kiev

1997-01-01

To produce vacancy defects, type Ia diamond was irradiated with 3.5 MeV electrons at doses of 5 centre dot 10 16 , 2 centre dot 10 17 , 4 centre dot 10 17 , and 2 centre dot 10 18 e/cm -2 . After each dose, the specimen was investigated using positron annihilation (ACAR), optical spectroscopy in IR, visible regions, and EPR. From ACAR spectra, the S-parameters were found and positron trapping rates were determined. Their behaviour with increasing irradiation doses shows that, in type Ia diamond along with neutral vacancies V degree, deeper traps of positrons are formed, which are most likely vacancies in the negative charge state V - . Specific trapping rates of the V 0 and V - defects are found to be 1.3 centre dot 10 15 and 3.8 centre dot 10 15 s -1 , respectively; trapping cross sections for these defects are also estimated

Influence of the quantum dot geometry on p -shell transitions in differently charged quantum dots

Science.gov (United States)

Holtkemper, M.; Reiter, D. E.; Kuhn, T.

2018-02-01

Absorption spectra of neutral, negatively, and positively charged semiconductor quantum dots are studied theoretically. We provide an overview of the main energetic structure around the p -shell transitions, including the influence of nearby nominally dark states. Based on the envelope function approximation, we treat the four-band Luttinger theory as well as the direct and short-range exchange Coulomb interactions within a configuration interaction approach. The quantum dot confinement is approximated by an anisotropic harmonic potential. We present a detailed investigation of state mixing and correlations mediated by the individual interactions. Differences and similarities between the differently charged quantum dots are highlighted. Especially large differences between negatively and positively charged quantum dots become evident. We present a visualization of energetic shifts and state mixtures due to changes in size, in-plane asymmetry, and aspect ratio. Thereby we provide a better understanding of the experimentally hard to access question of quantum dot geometry effects. Our findings show a method to determine the in-plane asymmetry from photoluminescence excitation spectra. Furthermore, we supply basic knowledge for tailoring the strength of certain state mixtures or the energetic order of particular excited states via changes of the shape of the quantum dot. Such knowledge builds the basis to find the optimal QD geometry for possible applications and experiments using excited states.

Quantum dot-polymer conjugates for stable luminescent displays.

Science.gov (United States)

Ghimire, Sushant; Sivadas, Anjaly; Yuyama, Ken-Ichi; Takano, Yuta; Francis, Raju; Biju, Vasudevanpillai

2018-05-23

The broad absorption of light in the UV-Vis-NIR region and the size-based tunable photoluminescence color of semiconductor quantum dots make these tiny crystals one of the most attractive antennae in solar cells and phosphors in electrooptical devices. One of the primary requirements for such real-world applications of quantum dots is their stable and uniform distribution in optically transparent matrices. In this work, we prepare transparent thin films of polymer-quantum dot conjugates, where CdSe/ZnS quantum dots are uniformly distributed at high densities in a chitosan-polystyrene copolymer (CS-g-PS) matrix. Here, quantum dots in an aqueous solution are conjugated to the copolymer by a phase transfer reaction. With the stable conjugation of quantum dots to the copolymer, we prevent undesired phase separation between the two and aggregation of quantum dots. Furthermore, the conjugate allows us to prepare transparent thin films in which quantum dots are uniformly distributed at high densities. The CS-g-PS copolymer helps us in not only preserving the photoluminescence properties of quantum dots in the film but also rendering excellent photostability to quantum dots at the ensemble and single particle levels, making the conjugate a promising material for photoluminescence-based devices.

Evaluation of seismic reliability of steel moment resisting frames rehabilitated by concentric braces with probabilistic models

Directory of Open Access Journals (Sweden)

Fateme Rezaei

2017-08-01

Full Text Available Probability of structure failure which has been designed by "deterministic methods" can be more than the one which has been designed in similar situation using probabilistic methods and models considering "uncertainties". The main purpose of this research was to evaluate the seismic reliability of steel moment resisting frames rehabilitated with concentric braces by probabilistic models. To do so, three-story and nine-story steel moment resisting frames were designed based on resistant criteria of Iranian code and then they were rehabilitated based on controlling drift limitations by concentric braces. Probability of frames failure was evaluated by probabilistic models of magnitude, location of earthquake, ground shaking intensity in the area of the structure, probabilistic model of building response (based on maximum lateral roof displacement and probabilistic methods. These frames were analyzed under subcrustal source by sampling probabilistic method "Risk Tools" (RT. Comparing the exceedance probability of building response curves (or selected points on it of the three-story and nine-story model frames (before and after rehabilitation, seismic response of rehabilitated frames, was reduced and their reliability was improved. Also the main effective variables in reducing the probability of frames failure were determined using sensitivity analysis by FORM probabilistic method. The most effective variables reducing the probability of frames failure are  in the magnitude model, ground shaking intensity model error and magnitude model error

Results from the BRACE 1.5 study: Climate change impacts of 1.5 C and 2 C warming

Science.gov (United States)

O'Neill, B. C.; Anderson, B.; Monaghan, A. J.; Ren, X.; Sanderson, B.; Tebaldi, C.

2017-12-01

In 2015, 195 countries negotiated the Paris Agreement on climate change, which set long-term goals of limiting global mean warming to well below 2 C and possibly 1.5 C. This event stimulated substantial scientific interest in climate outcomes and impacts on society associated with those levels of warming. Recently, the first set of global climate model simulations explicitly designed to meet those targets were undertaken with the Community Earth System Model (CESM) for use by the research community (Sanderson et al, accepted). The BRACE 1.5 project models societal impacts from these climate outcomes, combined with assumptions about future socioeconomic conditions according to the Shared Socioeconomic Pathways. These analyses build on a recently completed study of the Benefits of Reduced Anthropogenic Climate changE (BRACE), published as a set of 20 papers in Climatic Change, which examined the difference in impacts between two higher scenarios resulting in about 2.5 C and 3.7 C warming by late this century. BRACE 1.5 consists of a set of six papers to be submitted to a special collection in Environmental Research Letters that takes a similar approach but focuses on impacts at 1.5 and 2 C warming. We ask whether impacts differ substantially between the two climate scenarios, accounting for uncertainty in climate outcomes through the use of initial condition ensembles of CESM simulations, and in societal conditions by using alternative SSP-based development pathways. Impact assessment focuses on the health and agricultural sectors; modeling approaches include the use of a global mutli-region CGE model for economic analysis, both a process-based and an empirical crop model, a model of spatial population change, a model of climatic suitability for the aedes aegypti mosquito, and an epidemiological model of heat-related mortality. A methodological analysis also evaluates the use of climate model emulation techniques for providing climate information sufficient to

Andreev molecules in semiconductor nanowire double quantum dots.

Science.gov (United States)

Su, Zhaoen; Tacla, Alexandre B; Hocevar, Moïra; Car, Diana; Plissard, Sébastien R; Bakkers, Erik P A M; Daley, Andrew J; Pekker, David; Frolov, Sergey M

2017-09-19

Chains of quantum dots coupled to superconductors are promising for the realization of the Kitaev model of a topological superconductor. While individual superconducting quantum dots have been explored, control of longer chains requires understanding of interdot coupling. Here, double quantum dots are defined by gate voltages in indium antimonide nanowires. High transparency superconducting niobium titanium nitride contacts are made to each of the dots in order to induce superconductivity, as well as probe electron transport. Andreev bound states induced on each of dots hybridize to define Andreev molecular states. The evolution of these states is studied as a function of charge parity on the dots, and in magnetic field. The experiments are found in agreement with a numerical model.Quantum dots in a nanowire are one possible approach to creating a solid-state quantum simulator. Here, the authors demonstrate the coupling of electronic states in a double quantum dot to form Andreev molecule states; a potential building block for longer chains suitable for quantum simulation.

Quantum optics with single quantum dot devices

International Nuclear Information System (INIS)

Zwiller, Valery; Aichele, Thomas; Benson, Oliver

2004-01-01

A single radiative transition in a single-quantum emitter results in the emission of a single photon. Single quantum dots are single-quantum emitters with all the requirements to generate single photons at visible and near-infrared wavelengths. It is also possible to generate more than single photons with single quantum dots. In this paper we show that single quantum dots can be used to generate non-classical states of light, from single photons to photon triplets. Advanced solid state structures can be fabricated with single quantum dots as their active region. We also show results obtained on devices based on single quantum dots

Thermodynamics of the amalgam cells {l_brace}Cs-amalgam|CsX (m)|AgX|Ag{r_brace} (X=Cl, Br, I) and primary medium effects in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures

Energy Technology Data Exchange (ETDEWEB)

Falciola, Luigi [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy)]. E-mail: luigi.falciola@unimi.it; Longoni, Giorgio [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy); Mussini, Patrizia R. [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy)]. E-mail: patrizia.mussini@unimi.it; Mussini, Torquato [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy)]. E-mail: torquato.mussini@unimi.it

2006-06-15

The potential difference E of the amalgam cell {l_brace}Cs{sub x}Hg{sub 1-x}|CsX (m)|AgX|Ag{r_brace} (X=Cl, Br, I) has been measured as a function of the mole fraction x{sub Cs} of Cs metal in amalgams and of the molality m of CsX in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures containing up to 0.75 mass fraction of the organic component, at the temperature 298.15K. The respective standard molal potential differences E{sub m}{sup o} have been determined together with the relevant activity coefficients {gamma}{sub +}/- as functions of the CsX molality. The found E{sub m}{sup o} values show a parabolic decrease with increasing proportion of the organic component in the solvent mixture. Analysis of the relevant primary medium effects upon CsX shows that the CsX transfer from the standard state in water to the standard state in the (aqueous+organic) mixture is always unfavoured, and the acetonitrile is the least unfavoured co-solvent studied. Analysis of the primary medium effect upon CsI in terms of Feakins and French's theory leads to a primary hydration number close to zero, which is consistent with the results of supplementary EXAFS experiments on Cs{sup +} and I{sup -} in (acetonitrile+water) solvent mixtures.

PREFACE: Quantum Dot 2010

Science.gov (United States)

Taylor, Robert A.

2010-09-01

These conference proceedings contain the written papers of the contributions presented at Quantum Dot 2010 (QD2010). The conference was held in Nottingham, UK, on 26-30 April 2010. The conference addressed topics in research on: 1. Epitaxial quantum dots (including self-assembled and interface structures, dots defined by electrostatic gates etc): optical properties and electron transport quantum coherence effects spin phenomena optics of dots in cavities interaction with surface plasmons in metal/semiconductor structures opto-electronics applications 2. Novel QD structures: fabrication and physics of graphene dots, dots in nano-wires etc 3. Colloidal quantum dots: growth (shape control and hybrid nanocrystals such as metal/semiconductor, magnetic/semiconductor) assembly and surface functionalisation optical properties and spin dynamics electrical and magnetic properties applications (light emitting devices and solar cells, biological and medical applications, data storage, assemblers) The Editors Acknowledgements Conference Organising Committee: Maurice Skolnick (Chair) Alexander Tartakovskii (Programme Chair) Pavlos Lagoudakis (Programme Chair) Max Migliorato (Conference Secretary) Paola Borri (Publicity) Robert Taylor (Proceedings) Manus Hayne (Treasurer) Ray Murray (Sponsorship) Mohamed Henini (Local Organiser) International Advisory Committee: Yasuhiko Arakawa (Tokyo University, Japan) Manfred Bayer (Dortmund University, Germany) Sergey Gaponenko (Stepanov Institute of Physics, Minsk, Belarus) Pawel Hawrylak (NRC, Ottawa, Canada) Fritz Henneberger (Institute for Physics, Berlin, Germany) Atac Imamoglu (ETH, Zurich, Switzerland) Paul Koenraad (TU Eindhoven, Nethehrlands) Guglielmo Lanzani (Politecnico di Milano, Italy) Jungil Lee (Korea Institute of Science and Technology, Korea) Henri Mariette (CNRS-CEA, Grenoble, France) Lu Jeu Sham (San Diego, USA) Andrew Shields (Toshiba Research Europe, Cambridge, UK) Yoshihisa Yamamoto (Stanford University, USA) Artur

How to improve aesthetics in patients with Adolescent Idiopathic Scoliosis (AIS: a SPoRT brace treatment according to SOSORT management criteria

Directory of Open Access Journals (Sweden)

Fusco Claudia

2009-09-01

Full Text Available Abstract Background Aesthetics is a main goal of both conservative and surgical treatments in adolescent idiopathic scoliosis (AIS. Previously, we developed and validated a clinical scale - the Aesthetic Index (AI--in order to measure aesthetic impairment and changes during treatment. Aim To verify the efficacy of bracing on aesthetics in AIS. Study Design Prospective Cohort Study. Population Thirty-four consecutive patients, age 13.2 ± 3.7, initial Cobb Angle 32 ± 12°, ATR 10 ± 4° Bunnel, 11 males. Methods Patients with AI scores of at least 5/6 were included. Each of them had a brace prescription (18 to 23 hours per day, according to the SPoRT concept. AI was measured again after six months and at the end of treatment, and then the pre- and post-treatment scores compared. The Wilcoxon test was performed. Results Twenty-nine patients out of the 34 included completed the treatment and had six-month and final results; four patients were lost during the treatment, and one was fused. At baseline, median AI was 6 (95% IC 5-6 but the score decreased to 3 (95% IC 0-5; p Conclusion Aesthetics can be improved in a clinically significant way when the brace treatment is performed according to the SPoRT concept and by following the SOSORT management criteria. This is a relevant result for patients and a major goal of scoliosis treatment, be it conservative or surgical. The use of a more sensitive tool like TRACE could more easily detect the clinical changes; nevertheless, AI proved sensible enough that its use in everyday clinical practice can be suggested.

Elimination of Bimodal Size in InAs/GaAs Quantum Dots for Preparation of 1.3-μm Quantum Dot Lasers.

Science.gov (United States)

Su, Xiang-Bin; Ding, Ying; Ma, Ben; Zhang, Ke-Lu; Chen, Ze-Sheng; Li, Jing-Lun; Cui, Xiao-Ran; Xu, Ying-Qiang; Ni, Hai-Qiao; Niu, Zhi-Chuan

2018-02-21

The device characteristics of semiconductor quantum dot lasers have been improved with progress in active layer structures. Self-assembly formed InAs quantum dots grown on GaAs had been intensively promoted in order to achieve quantum dot lasers with superior device performances. In the process of growing high-density InAs/GaAs quantum dots, bimodal size occurs due to large mismatch and other factors. The bimodal size in the InAs/GaAs quantum dot system is eliminated by the method of high-temperature annealing and optimized the in situ annealing temperature. The annealing temperature is taken as the key optimization parameters, and the optimal annealing temperature of 680 °C was obtained. In this process, quantum dot growth temperature, InAs deposition, and arsenic (As) pressure are optimized to improve quantum dot quality and emission wavelength. A 1.3-μm high-performance F-P quantum dot laser with a threshold current density of 110 A/cm 2 was demonstrated.

Quantum-dot-in-perovskite solids

KAUST Repository

Ning, Zhijun; Gong, Xiwen; Comin, Riccardo; Walters, Grant; Fan, Fengjia; Voznyy, Oleksandr; Yassitepe, Emre; Buin, Andrei; Hoogland, Sjoerd; Sargent, Edward H.

2015-01-01

© 2015 Macmillan Publishers Limited. All rights reserved. Heteroepitaxy - atomically aligned growth of a crystalline film atop a different crystalline substrate - is the basis of electrically driven lasers, multijunction solar cells, and blue-light-emitting diodes. Crystalline coherence is preserved even when atomic identity is modulated, a fact that is the critical enabler of quantum wells, wires, and dots. The interfacial quality achieved as a result of heteroepitaxial growth allows new combinations of materials with complementary properties, which enables the design and realization of functionalities that are not available in the single-phase constituents. Here we show that organohalide perovskites and preformed colloidal quantum dots, combined in the solution phase, produce epitaxially aligned 'dots-in-a-matrix' crystals. Using transmission electron microscopy and electron diffraction, we reveal heterocrystals as large as about 60 nanometres and containing at least 20 mutually aligned dots that inherit the crystalline orientation of the perovskite matrix. The heterocrystals exhibit remarkable optoelectronic properties that are traceable to their atom-scale crystalline coherence: photoelectrons and holes generated in the larger-bandgap perovskites are transferred with 80% efficiency to become excitons in the quantum dot nanocrystals, which exploit the excellent photocarrier diffusion of perovskites to produce bright-light emission from infrared-bandgap quantum-tuned materials. By combining the electrical transport properties of the perovskite matrix with the high radiative efficiency of the quantum dots, we engineer a new platform to advance solution-processed infrared optoelectronics.

Quantum-dot-in-perovskite solids

KAUST Repository

Ning, Zhijun

2015-07-15

© 2015 Macmillan Publishers Limited. All rights reserved. Heteroepitaxy - atomically aligned growth of a crystalline film atop a different crystalline substrate - is the basis of electrically driven lasers, multijunction solar cells, and blue-light-emitting diodes. Crystalline coherence is preserved even when atomic identity is modulated, a fact that is the critical enabler of quantum wells, wires, and dots. The interfacial quality achieved as a result of heteroepitaxial growth allows new combinations of materials with complementary properties, which enables the design and realization of functionalities that are not available in the single-phase constituents. Here we show that organohalide perovskites and preformed colloidal quantum dots, combined in the solution phase, produce epitaxially aligned \\'dots-in-a-matrix\\' crystals. Using transmission electron microscopy and electron diffraction, we reveal heterocrystals as large as about 60 nanometres and containing at least 20 mutually aligned dots that inherit the crystalline orientation of the perovskite matrix. The heterocrystals exhibit remarkable optoelectronic properties that are traceable to their atom-scale crystalline coherence: photoelectrons and holes generated in the larger-bandgap perovskites are transferred with 80% efficiency to become excitons in the quantum dot nanocrystals, which exploit the excellent photocarrier diffusion of perovskites to produce bright-light emission from infrared-bandgap quantum-tuned materials. By combining the electrical transport properties of the perovskite matrix with the high radiative efficiency of the quantum dots, we engineer a new platform to advance solution-processed infrared optoelectronics.

Quantum dots for quantum information technologies

CERN Document Server

2017-01-01

This book highlights the most recent developments in quantum dot spin physics and the generation of deterministic superior non-classical light states with quantum dots. In particular, it addresses single quantum dot spin manipulation, spin-photon entanglement and the generation of single-photon and entangled photon pair states with nearly ideal properties. The role of semiconductor microcavities, nanophotonic interfaces as well as quantum photonic integrated circuits is emphasized. The latest theoretical and experimental studies of phonon-dressed light matter interaction, single-dot lasing and resonance fluorescence in QD cavity systems are also provided. The book is written by the leading experts in the field.

Coherent transport through interacting quantum dots

Energy Technology Data Exchange (ETDEWEB)

Hiltscher, Bastian

2012-10-05

The present thesis is composed of four different works. All deal with coherent transport through interacting quantum dots, which are tunnel-coupled to external leads. There a two main motivations for the use of quantum dots. First, they are an ideal device to study the influence of strong Coulomb repulsion, and second, their discrete energy levels can easily be tuned by external gate electrodes to create different transport regimes. The expression of coherence includes a very wide range of physical correlations and, therefore, the four works are basically independent of each other. Before motivating and introducing the different works in more detail, we remark that in all works a diagrammatic real-time perturbation theory is used. The fermionic degrees of freedom of the leads are traced out and the elements of the resulting reduced density matrix can be treated explicitly by means of a generalized master equation. How this equation is solved, depends on the details of the problem under consideration. In the first of the four works adiabatic pumping through an Aharonov-Bohm interferometer with a quantum dot embedded in each of the two arms is studied. In adiabatic pumping transport is generated by varying two system parameters periodically in time. We consider the two dot levels to be these two pumping parameters. Since they are located in different arms of the interferometer, pumping is a quantum mechanical effect purely relying on coherent superpositions of the dot states. It is very challenging to identify a quantum pumping mechanism in experiments, because a capacitive coupling of the gate electrodes to the leads may yield an undesired AC bias voltage, which is rectified by a time dependent conductance. Therefore, distinguishing features of these two transport mechanisms are required. We find that the dependence on the magnetic field is the key feature. While the pumped charge is an odd function of the magnetic flux, the rectified current is even, at least in

Coherent transport through interacting quantum dots

International Nuclear Information System (INIS)

Hiltscher, Bastian

2012-01-01

The present thesis is composed of four different works. All deal with coherent transport through interacting quantum dots, which are tunnel-coupled to external leads. There a two main motivations for the use of quantum dots. First, they are an ideal device to study the influence of strong Coulomb repulsion, and second, their discrete energy levels can easily be tuned by external gate electrodes to create different transport regimes. The expression of coherence includes a very wide range of physical correlations and, therefore, the four works are basically independent of each other. Before motivating and introducing the different works in more detail, we remark that in all works a diagrammatic real-time perturbation theory is used. The fermionic degrees of freedom of the leads are traced out and the elements of the resulting reduced density matrix can be treated explicitly by means of a generalized master equation. How this equation is solved, depends on the details of the problem under consideration. In the first of the four works adiabatic pumping through an Aharonov-Bohm interferometer with a quantum dot embedded in each of the two arms is studied. In adiabatic pumping transport is generated by varying two system parameters periodically in time. We consider the two dot levels to be these two pumping parameters. Since they are located in different arms of the interferometer, pumping is a quantum mechanical effect purely relying on coherent superpositions of the dot states. It is very challenging to identify a quantum pumping mechanism in experiments, because a capacitive coupling of the gate electrodes to the leads may yield an undesired AC bias voltage, which is rectified by a time dependent conductance. Therefore, distinguishing features of these two transport mechanisms are required. We find that the dependence on the magnetic field is the key feature. While the pumped charge is an odd function of the magnetic flux, the rectified current is even, at least in

Graphene quantum dots

CERN Document Server

Güçlü, Alev Devrim; Korkusinski, Marek; Hawrylak, Pawel

2014-01-01

This book reflects the current status of theoretical and experimental research of graphene based nanostructures, in particular quantum dots, at a level accessible to young researchers, graduate students, experimentalists and theorists. It presents the current state of research of graphene quantum dots, a single or few monolayer thick islands of graphene. It introduces the reader to the electronic and optical properties of graphite, intercalated graphite and graphene, including Dirac fermions, Berry's phase associated with sublattices and valley degeneracy, covers single particle properties of

Magneto-optical absorption in semiconducting spherical quantum dots: Influence of the dot-size, confining potential, and magnetic field

Directory of Open Access Journals (Sweden)

Manvir S. Kushwaha

2014-12-01

Full Text Available Semiconducting quantum dots – more fancifully dubbed artificial atoms – are quasi-zero dimensional, tiny, man-made systems with charge carriers completely confined in all three dimensions. The scientific quest behind the synthesis of quantum dots is to create and control future electronic and optical nanostructures engineered through tailoring size, shape, and composition. The complete confinement – or the lack of any degree of freedom for the electrons (and/or holes – in quantum dots limits the exploration of spatially localized elementary excitations such as plasmons to direct rather than reciprocal space. Here we embark on a thorough investigation of the magneto-optical absorption in semiconducting spherical quantum dots characterized by a confining harmonic potential and an applied magnetic field in the symmetric gauge. This is done within the framework of Bohm-Pines’ random-phase approximation that enables us to derive and discuss the full Dyson equation that takes proper account of the Coulomb interactions. As an application of our theoretical strategy, we compute various single-particle and many-particle phenomena such as the Fock-Darwin spectrum; Fermi energy; magneto-optical transitions; probability distribution; and the magneto-optical absorption in the quantum dots. It is observed that the role of an applied magnetic field on the absorption spectrum is comparable to that of a confining potential. Increasing (decreasing the strength of the magnetic field or the confining potential is found to be analogous to shrinking (expanding the size of the quantum dots: resulting into a blue (red shift in the absorption spectrum. The Fermi energy diminishes with both increasing magnetic-field and dot-size; and exhibits saw-tooth-like oscillations at large values of field or dot-size. Unlike laterally confined quantum dots, both (upper and lower magneto-optical transitions survive even in the extreme instances. However, the intra

Magneto-optical absorption in semiconducting spherical quantum dots: Influence of the dot-size, confining potential, and magnetic field

Energy Technology Data Exchange (ETDEWEB)

Kushwaha, Manvir S. [Department of Physics and Astronomy, Rice University, P.O. Box 1892, Houston, TX 77251 (United States)

2014-12-15

Semiconducting quantum dots – more fancifully dubbed artificial atoms – are quasi-zero dimensional, tiny, man-made systems with charge carriers completely confined in all three dimensions. The scientific quest behind the synthesis of quantum dots is to create and control future electronic and optical nanostructures engineered through tailoring size, shape, and composition. The complete confinement – or the lack of any degree of freedom for the electrons (and/or holes) – in quantum dots limits the exploration of spatially localized elementary excitations such as plasmons to direct rather than reciprocal space. Here we embark on a thorough investigation of the magneto-optical absorption in semiconducting spherical quantum dots characterized by a confining harmonic potential and an applied magnetic field in the symmetric gauge. This is done within the framework of Bohm-Pines’ random-phase approximation that enables us to derive and discuss the full Dyson equation that takes proper account of the Coulomb interactions. As an application of our theoretical strategy, we compute various single-particle and many-particle phenomena such as the Fock-Darwin spectrum; Fermi energy; magneto-optical transitions; probability distribution; and the magneto-optical absorption in the quantum dots. It is observed that the role of an applied magnetic field on the absorption spectrum is comparable to that of a confining potential. Increasing (decreasing) the strength of the magnetic field or the confining potential is found to be analogous to shrinking (expanding) the size of the quantum dots: resulting into a blue (red) shift in the absorption spectrum. The Fermi energy diminishes with both increasing magnetic-field and dot-size; and exhibits saw-tooth-like oscillations at large values of field or dot-size. Unlike laterally confined quantum dots, both (upper and lower) magneto-optical transitions survive even in the extreme instances. However, the intra-Landau level

[Analysis on workload for hospital DOTS service].

Science.gov (United States)

Nagata, Yoko; Urakawa, Minako; Kobayashi, Noriko; Kato, Seiya

2014-04-01

A directly observed treatment short course (DOTS) trial was launched in Japan in the late 1990s and targeted patients with social depression at urban areas. Based on these findings, the Ministry of Health, Labour and Welfare established the Japanese DOTS Strategy in 2003, which is a comprehensive support service ensuring the adherence of tuberculosis patients to drug administration. DOTS services are initially provided at the hospital to patients with infectious tuberculosis who are hospitalized according to the Infectious Diseases Control Law. After being discharged from the hospital, the patients are referred to a public health center. However, a survey conducted in 2008 indicated that all the patients do not receive appropriate DOTS services at some hospitals. In the present study, we aimed to evaluate the protocols and workload of DOTS at hospitals that are actively involved in tuberculosis medical practice, including DOTS, to assess whether the hospital DOTS services were adequate. We reviewed a series of articles on hospital DOTS from a Japanese journal on nursing for tuberculosis patients and identified 25 activities regarding the hospital DOTS service. These 25 items were then classified into 3 categories: health education to patients, support for adherence, and coordination with the health center. In total, 20 hospitals that had > 20 authorized tuberculosis beds were selected--while considering the geographical balance, schedule of this survey, etc.--from 33 hospitals where an ex-trainee of the tuberculosis control expert training program in the Research Institute of Tuberculosis (RIT) was working and 20 hospitals that had collaborated with our previous survey on tuberculosis medical facilities. All the staff associated with the DOTS service were asked to record the total working time as well as the time spent for each activity. The data were collected and analyzed at the RIT. The working times for each activity of the DOTS service for nurses, pharmacists

49 CFR 41.119 - DOT regulated buildings.

Science.gov (United States)

2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false DOT regulated buildings. 41.119 Section 41.119 Transportation Office of the Secretary of Transportation SEISMIC SAFETY § 41.119 DOT regulated buildings. (a) Each DOT Operating Administration with responsibility for regulating the structural safety of buildings...

Synthetic Developments of Nontoxic Quantum Dots.

Science.gov (United States)

Das, Adita; Snee, Preston T

2016-03-03

Semiconductor nanocrystals, or quantum dots (QDs), are candidates for biological sensing, photovoltaics, and catalysis due to their unique photophysical properties. The most studied QDs are composed of heavy metals like cadmium and lead. However, this engenders concerns over heavy metal toxicity. To address this issue, numerous studies have explored the development of nontoxic (or more accurately less toxic) quantum dots. In this Review, we select three major classes of nontoxic quantum dots composed of carbon, silicon and Group I-III-VI elements and discuss the myriad of synthetic strategies and surface modification methods to synthesize quantum dots composed of these material systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

MOVPE grown InGaAs quantum dots of high optical quality as seed layer for low-density InP quantum dots

International Nuclear Information System (INIS)

Richter, D; Hafenbrak, R; Joens, K D; Schulz, W-M; Eichfelder, M; Rossbach, R; Jetter, M; Michler, P

2010-01-01

To achieve a low density of optically active InP-quantum dots we used InGaAs islands embedded in GaAs as a seed layer. First, the structural InGaAs quantum dot properties and the influence of the annealing technique was investigated by atomic force microscope measurements. High-resolution micro-photoluminescence spectra reveal narrow photoluminescence lines, with linewidths down to 11 μeV and fine structure splittings of 25 μeV. Furthermore, using these InGaAs quantum dots as seed layer reduces the InP quantum dot density of optically active quantum dots drastically. InP quantum dot excitonic photoluminescence emission with a linewidth of 140 μeV has been observed.

Spin current through quantum-dot spin valves

International Nuclear Information System (INIS)

Wang, J; Xing, D Y

2006-01-01

We report a theoretical study of the influence of the Coulomb interaction on the equilibrium spin current in a quantum-dot spin valve, in which the quantum dot described by the Anderson impurity model is coupled to two ferromagnetic leads with noncollinear magnetizations. In the Kondo regime, electrons transmit through the quantum dot via higher-order virtual processes, in which the spin of either lead electrons or a localized electron on the quantum dot may reverse. It is found that the magnitude of the spin current decreases with increasing Coulomb interactions due to spin flip effects on the dot. However, the spatial direction of the spin current remains unchanged; it is determined only by the exchange coupling between two noncollinear magnetizations

Entangled exciton states in quantum dot molecules

Science.gov (United States)

Bayer, Manfred

2002-03-01

Currently there is strong interest in quantum information processing(See, for example, The Physics of Quantum Information, eds. D. Bouwmeester, A. Ekert and A. Zeilinger (Springer, Berlin, 2000).) in a solid state environment. Many approaches mimic atomic physics concepts in which semiconductor quantum dots are implemented as artificial atoms. An essential building block of a quantum processor is a gate which entangles the states of two quantum bits. Recently a pair of vertically aligned quantum dots has been suggested as optically driven quantum gate(P. Hawrylak, S. Fafard, and Z. R. Wasilewski, Cond. Matter News 7, 16 (1999).)(M. Bayer, P. Hawrylak, K. Hinzer, S. Fafard, M. Korkusinski, Z.R. Wasilewski, O. Stern, and A. Forchel, Science 291, 451 (2001).): The quantum bits are individual carriers either on dot zero or dot one. The different dot indices play the same role as a "spin", therefore we call them "isospin". Quantum mechanical tunneling between the dots rotates the isospin and leads to superposition of these states. The quantum gate is built when two different particles, an electron and a hole, are created optically. The two particles form entangled isospin states. Here we present spectrocsopic studies of single self-assembled InAs/GaAs quantum dot molecules that support the feasibility of this proposal. The evolution of the excitonic recombination spectrum with varying separation between the dots allows us to demonstrate coherent tunneling of carriers across the separating barrier and the formation of entangled exciton states: Due to the coupling between the dots the exciton states show a splitting that increases with decreasing barrier width. For barrier widths below 5 nm it exceeds the thermal energy at room temperature. For a given barrier width, we find only small variations of the tunneling induced splitting demonstrating a good homogeneity within a molecule ensemble. The entanglement may be controlled by application of electromagnetic field. For

Synthesis of CdSe quantum dots for quantum dot sensitized solar cell

Energy Technology Data Exchange (ETDEWEB)

Singh, Neetu, E-mail: singh.neetu1985@gmail.com; Kapoor, Avinashi [Department of Electronic Science, University of Delhi South Campus, New Delhi-110 021 (India); Kumar, Vinod [Department of Physics, University of the Free State, Bloemfontein, ZA9300 (South Africa); Mehra, R. M. [School of Engineering and Technology, Sharda University, Greater Noida-201 306, U.P. (India)

2014-04-24

CdSe Quantum Dots (QDs) of size 0.85 nm were synthesized using chemical route. ZnO based Quantum Dot Sensitized Solar Cell (QDSSC) was fabricated using CdSe QDs as sensitizer. The Pre-synthesized QDs were found to be successfully adsorbed on front ZnO electrode and had potential to replace organic dyes in Dye Sensitized Solar Cells (DSSCs). The efficiency of QDSSC was obtained to be 2.06 % at AM 1.5.

Experimental and theoretical studies of d-dot

International Nuclear Information System (INIS)

Ishida, Takekazu; Fujii, Masaki; Abe, Taiji; Yamamoto, Masuo; Miki, Shigehito; Kawamata, Shuichi; Satoh, Kazuo; Yotsuya, Tsutomu; Kato, Masaru; Machida, Masahiko; Koyama, Tomio; Terashima, Takahito; Tsukui, Shigeki; Adachi, Motoaki

2006-01-01

We propose the idea of d-dot, where a d-wave superconducting dot is embedded in s-wave matrix. Spontaneous half vortices should appear in the four corners of the d-dot [M. Kato, M. Ako, M. Machida, T. Koyama, T. Ishida, Physica C 412-414 (2004) 352; M. Ako, M. Kato, M. Machida, T. Koyama, T. Ishida, Physica C 412-414 (2004) 544; M. Fujii, T. Abe, H. Yoshikawa, S. Miki, S. Kawamata, K. Satoh, T. Yotsuya, M. Kato, M. Machida, T. Koyama, T. Terashima, S. Tsukui, M. Adachi, T. Ishida, Physica C 426-431 (2005) 104]. Symmetric geometry and the fourfold symmetry of the d-dot would be suitable as a building block for constructing the novel physical systems. The phase dynamics of a closed 0-π junction, which can be realized in a small d x 2 -y 2 -dot, is mapped on a quantum two-level system when the system size is small enough. Using two-component Ginzburg-Landau equation, we study the physical properties of d-dots systematically. We prepare epitaxial YBa 2 Cu 3 O 7 (YBCO) films of thickness 100nm on SrTiO 3 substrates using a laser ablation apparatus. The d-dot is fabricated by a photolithography, electron beam lithography EB and an electron cyclotron resonance (ECR) etching, a focused ion beam microscope, and a lift-off technique. Local vortex profile is investigated using a SQUID microscope when d-dot is cooled in zero field

Patients' costs and cost-effectiveness of tuberculosis treatment in DOTS and non-DOTS facilities in Rio de Janeiro, Brazil.

Directory of Open Access Journals (Sweden)

Ricardo Steffen

2010-11-01

Full Text Available Costs of tuberculosis diagnosis and treatment may represent a significant burden for the poor and for the health system in resource-poor countries.The aim of this study was to analyze patients' costs of tuberculosis care and to estimate the incremental cost-effectiveness ratio (ICER of the directly observed treatment (DOT strategy per completed treatment in Rio de Janeiro, Brazil.We interviewed 218 adult patients with bacteriologically confirmed pulmonary tuberculosis. Information on direct (out-of-pocket expenses and indirect (hours lost costs, loss in income and costs with extra help were gathered through a questionnaire. Healthcare system additional costs due to supervision of pill-intake were calculated considering staff salaries. Effectiveness was measured by treatment completion rate. The ICER of DOT compared to self-administered therapy (SAT was calculated.DOT increased costs during the treatment phase, while SAT increased costs in the pre-diagnostic phase, for both the patient and the health system. Treatment completion rates were 71% in SAT facilities and 79% in DOT facilities. Costs per completed treatment were US$ 194 for patients and U$ 189 for the health system in SAT facilities, compared to US$ 336 and US$ 726 in DOT facilities. The ICER was US$ 6,616 per completed DOT treatment compared to SAT.Costs incurred by TB patients are high in Rio de Janeiro, especially for those under DOT. The DOT strategy doubles patients' costs and increases by fourfold the health system costs per completed treatment. The additional costs for DOT may be one of the contributing factors to the completion rates below the targeted 85% recommended by WHO.

Core–shell quantum dots: Properties and applications

Energy Technology Data Exchange (ETDEWEB)

Vasudevan, D., E-mail: vasudevand@rediffmail.com [Electrodics and electrocatalysis division, CSIR-CECRI, Karaikudi 630006 (India); Gaddam, Rohit Ranganathan [Amity Institute of Nanotechnology, Amity University, Noida 201301 (India); Trinchi, Adrian; Cole, Ivan [CSIRO Materials Science and Engineering, Clayton South MDC, 3169 (Australia)

2015-07-05

Fluorescent quantum dots (QDs) are semiconducting nanocrystals (NCs) that find numerous applications in areas, such as bio labelling, sensors, lasers, light emitting diodes and medicine. Core–shell quantum dots were developed to improve the photoluminescence efficiency of single quantum dots. Capping their surface with organic ligands as well as their extraction into aqueous media enables their use in sensing applications. The current review highlights the importance and applications of core shell quantum dots as well as their surface modifications and applications in the field of medicine and as sensors for chemical and biochemical analysis.

Core–shell quantum dots: Properties and applications

International Nuclear Information System (INIS)

Vasudevan, D.; Gaddam, Rohit Ranganathan; Trinchi, Adrian; Cole, Ivan

2015-01-01

Fluorescent quantum dots (QDs) are semiconducting nanocrystals (NCs) that find numerous applications in areas, such as bio labelling, sensors, lasers, light emitting diodes and medicine. Core–shell quantum dots were developed to improve the photoluminescence efficiency of single quantum dots. Capping their surface with organic ligands as well as their extraction into aqueous media enables their use in sensing applications. The current review highlights the importance and applications of core shell quantum dots as well as their surface modifications and applications in the field of medicine and as sensors for chemical and biochemical analysis

Correlation effects in side-coupled quantum dots

International Nuclear Information System (INIS)

Zitko, R; Bonca, J

2007-01-01

Using Wilson's numerical renormalization group (NRG) technique, we compute zero-bias conductance and various correlation functions of a double quantum dot (DQD) system. We present different regimes within a phase diagram of the DQD system. By introducing a negative Hubbard U on one of the quantum dots, we simulate the effect of electron-phonon coupling and explore the properties of the coexisting spin and charge Kondo state. In a triple quantum dot (TQD) system, a multi-stage Kondo effect appears where localized moments on quantum dots are screened successively at exponentially distinct Kondo temperatures

Wannier-Frenkel hybrid exciton in organic-semiconductor quantum dot heterostructures

International Nuclear Information System (INIS)

Birman, Joseph L.; Huong, Nguyen Que

2007-01-01

The formation of a hybridization state of Wannier Mott exciton and Frenkel exciton in different hetero-structure configurations involving quantum dots is investigated. The hybrid excitons exist at the interfaces of the semiconductors quantum dots and the organic medium, having unique properties and a large optical non-linearity. The coupling at resonance is very strong and tunable by changing the parameters of the systems (dot radius, dot-dot distance, generation of the organic dendrites and the materials of the system etc...). Different semiconductor quantum dot-organic material combination systems have been considered such as a semiconductor quantum dot lattice embedded in an organic host, a semiconductor quantum dot at the center of an organic dendrite, a semiconductor quantum dot coated by an organic shell

Analysis of Limit Cycle Oscillation Data from the Aeroelastic Test of the SUGAR Truss-Braced Wing Model

Science.gov (United States)

Bartels, Robert E.; Funk, Christie; Scott, Robert C.

2015-01-01

Research focus in recent years has been given to the design of aircraft that provide significant reductions in emissions, noise and fuel usage. Increases in fuel efficiency have also generally been attended by overall increased wing flexibility. The truss-braced wing (TBW) configuration has been forwarded as one that increases fuel efficiency. The Boeing company recently tested the Subsonic Ultra Green Aircraft Research (SUGAR) Truss-Braced Wing (TBW) wind-tunnel model in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). This test resulted in a wealth of accelerometer data. Other publications have presented details of the construction of that model, the test itself, and a few of the results of the test. This paper aims to provide a much more detailed look at what the accelerometer data says about the onset of aeroelastic instability, usually known as flutter onset. Every flight vehicle has a location in the flight envelope of flutter onset, and the TBW vehicle is not different. For the TBW model test, the flutter onset generally occurred at the conditions that the Boeing company analysis said it should. What was not known until the test is that, over a large area of the Mach number dynamic pressure map, the model displayed wing/engine nacelle aeroelastic limit cycle oscillation (LCO). This paper dissects that LCO data in order to provide additional insights into the aeroelastic behavior of the model.

The quantum Hall effect in quantum dot systems

International Nuclear Information System (INIS)

Beltukov, Y M; Greshnov, A A

2014-01-01

It is proposed to use quantum dots in order to increase the temperatures suitable for observation of the integer quantum Hall effect. A simple estimation using Fock-Darwin spectrum of a quantum dot shows that good part of carriers localized in quantum dots generate the intervals of plateaus robust against elevated temperatures. Numerical calculations employing local trigonometric basis and highly efficient kernel polynomial method adopted for computing the Hall conductivity reveal that quantum dots may enhance peak temperature for the effect by an order of magnitude, possibly above 77 K. Requirements to potentials, quality and arrangement of the quantum dots essential for practical realization of such enhancement are indicated. Comparison of our theoretical results with the quantum Hall measurements in InAs quantum dot systems from two experimental groups is also given

Silicon quantum dots: surface matters

Czech Academy of Sciences Publication Activity Database

Dohnalová, K.; Gregorkiewicz, T.; Kůsová, Kateřina

2014-01-01

Roč. 26, č. 17 (2014), 1-28 ISSN 0953-8984 R&D Projects: GA ČR GPP204/12/P235 Institutional support: RVO:68378271 Keywords : silicon quantum dots * quantum dot * surface chemistry * quantum confinement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.346, year: 2014

Spin interactions in InAs quantum dots and molecules

Energy Technology Data Exchange (ETDEWEB)

Doty, M.F.; Ware, M.E.; Stinaff, E.A.; Scheibner, M.; Bracker, A.S.; Ponomarev, I.V.; Badescu, S.C.; Reinecke, T.L.; Gammon, D. [Naval Research Lab, Washington, DC 20375 (United States); Korenev, V.L. [A.F. Ioffe Physical Technical Institute, St. Petersburg 194021 (Russian Federation)

2006-12-15

Spin interactions between particles in quantum dots or quantum dot molecules appear as fine structure in the photoluminescence spectra. Using the understanding of exchange interactions that has been developed from single dot spectra, we analyze the spin signatures of coupled quantum dots separated by a wide barrier such that inter-dot interactions are negligible. We find that electron-hole exchange splitting is directly evident. In dots charged with an excess hole, an effective hole-hole interaction can be turned on through tunnel coupling. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Artful and multifaceted applications of carbon dot in biomedicine.

Science.gov (United States)

Jaleel, Jumana Abdul; Pramod, K

2018-01-10

Carbon dots (C-dots) are luminescent carbon nanomaterial having good biocompatibility and low toxicity. The characteristic fluorescence emission property of C-dots establishes their role in optical imaging. C-dots which are superior to fluorescent dyes and semiconductor quantum dots act as a safer in vivo imaging probe. Apart from their bioimaging application, other applications in biomedicine such as drug delivery, cancer therapy, and gene delivery were studied. In this review, we present multifaceted applications of C-dots along with their synthesis, surface passivation, doping, and toxicity profile. Copyright © 2017 Elsevier B.V. All rights reserved.

Direct-Bandgap InAs Quantum-Dots Have Long-Range Electron--Hole Exchange Whereas Indirect Gap Si Dots Have Short-Range Exchange

International Nuclear Information System (INIS)

Juo, J.W.; Franceschetti, A.; Zunger, A.

2009-01-01

Excitons in quantum dots manifest a lower-energy spin-forbidden 'dark' state below a spin-allowed 'bright' state; this splitting originates from electron-hole (e-h) exchange interactions, which are strongly enhanced by quantum confinement. The e-h exchange interaction may have both a short-range and a long-range component. Calculating numerically the e-h exchange energies from atomistic pseudopotential wave functions, we show here that in direct-gap quantum dots (such as InAs) the e-h exchange interaction is dominated by the long-range component, whereas in indirect-gap quantum dots (such as Si) only the short-range component survives. As a result, the exciton dark/bright splitting scales as 1/R 2 in InAs dots and 1/R 3 in Si dots, where R is the quantum-dot radius.

Fingerprints of transversal and longitudinal coupling between induced open quantum dots in the longitudinal magneto-conductance through anti-dot lattices

International Nuclear Information System (INIS)

Ujevic, Sebastian; Mendoza, Michel

2011-01-01

Full text. We propose numerical simulations of longitudinal magneto conductance through a finite anti dot lattice located inside an open quantum dot with a magnetic field applied perpendicular to the plane. The system is connected to reservoirs using quantum point contacts. We discuss the relationship between the longitudinal magneto conductance and the generation of transversal couplings between the induced open quantum dots in the system. The system presents longitudinal magneto conductance maps with crossovers (between transversal bands) and closings (longitudinal decoupling) of fundamental quantum states related to the open quantum dots induced by the anti dot lattice. A relationship is observed between the distribution of anti dots and the formed conductance bands, allowing a systematic follow-up of the bands as a function of the applied magnetic field and quantum point contact width. We observed a high conductance intensity (between n- and (n + 1)-quantum of conductance, n = 1; 2...) in the regions of crossover and closing of states. This suggests transversal couplings between the induced open quantum dots of the system that can be modulated by varying both the anti dots potential and the quantum point contact width. A new continuous channel (not expected) is induced by the variation of the contact width and generate Fano resonances in the conductance. These resonances can be manipulated by the applied magnetic field

Quantum dot optoelectronic devices: lasers, photodetectors and solar cells

International Nuclear Information System (INIS)

Wu, Jiang; Chen, Siming; Seeds, Alwyn; Liu, Huiyun

2015-01-01

Nanometre-scale semiconductor devices have been envisioned as next-generation technologies with high integration and functionality. Quantum dots, or the so-called ‘artificial atoms’, exhibit unique properties due to their quantum confinement in all 3D. These unique properties have brought to light the great potential of quantum dots in optoelectronic applications. Numerous efforts worldwide have been devoted to these promising nanomaterials for next-generation optoelectronic devices, such as lasers, photodetectors, amplifiers, and solar cells, with the emphasis on improving performance and functionality. Through the development in optoelectronic devices based on quantum dots over the last two decades, quantum dot devices with exceptional performance surpassing previous devices are evidenced. This review describes recent developments in quantum dot optoelectronic devices over the last few years. The paper will highlight the major progress made in 1.3 μm quantum dot lasers, quantum dot infrared photodetectors, and quantum dot solar cells. (topical review)

Quantum dot systems: artificial atoms with tunable properties

International Nuclear Information System (INIS)

Weis, J.

2005-01-01

Full text: Quantum dots - also called zero-dimensional electron systems or artificial atoms - are physical objects where the constituent electrons are confined in a small spatial region, leading to discrete eigenvalues for the energies of the confined electrons. Large quantum dots offer a dense energy spectrum comparable to that of metallic grains, whereas small quantum dots more closely resemble atoms in their electronic properties. Quantum dots can be linked to leads by tunnel barriers, hence permitting electrical transport measurements: Coulomb blockade and single-electron charging effects are observed due to the repulsive electron electron interaction on the quantum dot site. Usually fabricated by conventional semiconductor growth and processing technology, the advantage is that both simple and also more complex quantum dot systems can be designed to purpose, acting as model systems with in-situ tunable parameters such as the number of confined electrons in the quantum dot and the strength of the tunnel coupling to the leads, electrostatically controlled by the applied voltages to gate electrodes. With increasing the tunnel coupling to the leads, the virtual occupation of the quantum dot from the leads becomes more and more important -- the simple description of electrical transport by single-electron tunneling events breaks down. The basic physics is described by the Kondo physics based on the Anderson impurity model. A system consisting of strongly electrostatically coupled quantum dots with separate leads to each quantum dot represent another realization of the Anderson impurity model. Experiments to verify the analogy are presented. The experimental data embedded within this tutorial have been obtained with Alexander Huebel, Matthias Keller, Joerg Schmid, David Quirion, Armin Welker, Ulf Wilhelm, and Klaus von Klitzing. (author)

Using of Quantum Dots in Biology and Medicine.

Science.gov (United States)

Pleskova, Svetlana; Mikheeva, Elza; Gornostaeva, Ekaterina

2018-01-01

Quantum dots are nanoparticles, which due to their unique physical and chemical (first of all optical) properties, are promising in biology and medicine. There are many ways for quantum dots synthesis, both in the form of nanoislands self-forming on the surfaces, which can be used as single-photon emitters in electronics for storing information, and in the form of colloidal quantum dots for diagnostic and therapeutic purposes in living systems. The paper describes the main methods of quantum dots synthesis and summarizes medical and biological ways of their use. The main emphasis is laid on the ways of quantum dots surface modification. Influence of the size and form of nanoparticles, charge on the surfaces of quantum dots, and cover type on the efficiency of internalization by cells and cell compartments is shown. The main mechanisms of penetration are considered.

Quantum Dots and Their Multimodal Applications: A Review

Directory of Open Access Journals (Sweden)

Paul H. Holloway

2010-03-01

Full Text Available Semiconducting quantum dots, whose particle sizes are in the nanometer range, have very unusual properties. The quantum dots have band gaps that depend in a complicated fashion upon a number of factors, described in the article. Processing-structure-properties-performance relationships are reviewed for compound semiconducting quantum dots. Various methods for synthesizing these quantum dots are discussed, as well as their resulting properties. Quantum states and confinement of their excitons may shift their optical absorption and emission energies. Such effects are important for tuning their luminescence stimulated by photons (photoluminescence or electric field (electroluminescence. In this article, decoupling of quantum effects on excitation and emission are described, along with the use of quantum dots as sensitizers in phosphors. In addition, we reviewed the multimodal applications of quantum dots, including in electroluminescence device, solar cell and biological imaging.

Spin interactions in InAs quantum dots

Science.gov (United States)

Doty, M. F.; Ware, M. E.; Stinaff, E. A.; Scheibner, M.; Bracker, A. S.; Gammon, D.; Ponomarev, I. V.; Reinecke, T. L.; Korenev, V. L.

2006-03-01

Fine structure splittings in optical spectra of self-assembled InAs quantum dots (QDs) generally arise from spin interactions between particles confined in the dots. We present experimental studies of the fine structure that arises from multiple charges confined in a single dot [1] or in molecular orbitals of coupled pairs of dots. To probe the underlying spin interactions we inject particles with a known spin orientation (by using polarized light to perform photoluminescence excitation spectroscopy experiments) or use a magnetic field to orient and/or mix the spin states. We develop a model of the spin interactions that aids in the development of quantum information processing applications based on controllable interactions between spins confined to QDs. [1] Polarized Fine Structure in the Photoluminescence Excitation Spectrum of a Negatively Charged Quantum Dot, Phys. Rev. Lett. 95, 177403 (2005)

Inter-dot coupling effects on transport through correlated parallel

Indian Academy of Sciences (India)

Transport through symmetric parallel coupled quantum dot system has been studied, using non-equilibrium Green function formalism. The inter-dot tunnelling with on-dot and inter-dot Coulomb repulsion is included. The transmission coefficient and Landaur–Buttiker like current formula are shown in terms of internal states ...

Two path transport measurements on a triple quantum dot

Energy Technology Data Exchange (ETDEWEB)

Rogge, Maximilian C.; Haug, Rolf J. [Institut fuer Festkoerperphysik, Leibniz Universitaet Hannover, Appelstr. 2, 30167 Hannover (Germany)

2008-07-01

We present a novel triple quantum dot device made with local anodic oxidation on a GaAs/AlGaAs heterostructure. The geometry provides two path transport via a three lead setup with each lead connected to one of the three quantum dots. In addition charge detection is implemented via a quantum point contact. One lead is used as a common source contact, the other two are used as two separate drain contacts with independent current measurement. Thus two paths are formed with two dots in each path. Along both paths serial transport is observed at the triple points of the two corresponding dots. With four side gates a wide tunability is given. Thus the system can be tuned in and out of triple dot resonances. When all three dots come into resonance, quadruple points are formed with simultaneous transport along both paths. The data are analysed in combined two colour plots and compared to the charge detection showing sets of three different lines, one for each dot. This way the two path setup allows to investigate the transition from double dot physics to triple dot physics.

Tunable single quantum dot nanocavities for cavity QED experiments

International Nuclear Information System (INIS)

Kaniber, M; Laucht, A; Neumann, A; Bichler, M; Amann, M-C; Finley, J J

2008-01-01

We present cavity quantum electrodynamics experiments performed on single quantum dots embedded in two-dimensional photonic crystal nanocavities. We begin by describing the structural and optical properties of the quantum dot sample and the photonic crystal nanocavities and compare the experimental results with three-dimensional calculations of the photonic properties. The influence of the tailored photonic environment on the quantum dot spontaneous emission dynamics is studied using spectrally and spatially dependent time-resolved spectroscopy. In ensemble and single dot measurements we show that the photonic crystals strongly enhance the photon extraction efficiency and, therefore, are a promising concept for realizing efficient single-photon sources. Furthermore, we demonstrate single-photon emission from an individual quantum dot that is spectrally detuned from the cavity mode. The need for controlling the spectral dot-cavity detuning is discussed on the basis of shifting either the quantum dot emission via temperature tuning or the cavity mode emission via a thin film deposition technique. Finally, we discuss the recently discovered non-resonant coupling mechanism between quantum dot emission and cavity mode for large detunings which drastically lowers the purity of single-photon emission from dots that are spectrally coupled to nanocavity modes.

Hubble's View of Little Blue Dots

Science.gov (United States)

Kohler, Susanna

2018-02-01

The recent discovery of a new type of tiny, star-forming galaxy is the latest in a zoo of detections shedding light on our early universe. What can we learn from the unique little blue dots found in archival Hubble data?Peas, Berries, and DotsGreen pea galaxies identified by citizen scientists with Galaxy Zoo. [Richard Nowell Carolin Cardamone]As telescope capabilities improve and we develop increasingly deeper large-scale surveys of our universe, we continue to learn more about small, faraway galaxies. In recent years, increasing sensitivity first enabled the detection of green peas luminous, compact, low-mass (10 billion solar masses; compare this to the Milky Ways 1 trillion solar masses!) galaxies with high rates of star formation.Not long thereafter, we discovered galaxies that form stars similarly rapidly, but are even smaller only 330 million solar masses, spanning less than 3,000 light-years in size. These tiny powerhouses were termed blueberries for their distinctive color.Now, scientists Debra and Bruce Elmegreen (of Vassar College and IBM Research Division, respectively) report the discovery of galaxies that have even higher star formation rates and even lower masses: little blue dots.Exploring Tiny Star FactoriesThe Elmegreens discovered these unique galaxies by exploring archival Hubble data. The Hubble Frontier Fields data consist of deep images of six distant galaxy clusters and the parallel fields next to them. It was in the archival data for two Frontier Field Parallels, those for clusters Abell 2744 and MAS J0416.1-2403, that the authors noticed several galaxies that stand out as tiny, bright, blue objects that are nearly point sources.Top: a few examples of the little blue dots recently identified in two Hubble Frontier Field Parallels. Bottom: stacked images for three different groups of little blue dots. [Elmegreen Elmegreen 2017]The authors performed a search through the two Frontier Field Parallels, discovering a total of 55 little blue dots

Novel Synthesis of Slightly Fluorinated Graphene Quantum Dots with Luminescent and Paramagnetic Properties through Thermal Cutting of Fluorinated Graphene

Science.gov (United States)

Feng, Qian; Xiao, Wenqing; Zheng, Yongping; Lin, Yuda; Li, Jiaxin; Ye, Qingying; Huang, Zhigao

2018-01-01

A novel approach has been developed to synthesize slightly fluorinated graphene quantum dots (GQDs-F) through thermal cutting of highly fluorinated graphene. The fluorinated graphene with substantial structure defects is fragile and is readily attacked. The direct evaporation of abundant CFn (n = 2, 3) groups near structure defects lead to the loss of adjacent skelton C atoms, and the fluorinated graphene can be thermally cut into GQDs-F with a relatively uniform nanosize in pyrolysis at 810 K. The GQDs-F with a low F/C atomic ratio of ca. 0.03 exhibit excitation wavelength-dependent properties with multicolor photoluminescence (PL) from blue to green. At the same time, F adatoms that are most likely located at the edges of GQDs-F have a high efficiency of introducing paramagnetic centres, and GQDs-F show a strong paramagnetism because of sp3-type defects and magnetic zigzag edges. The graphene quantum dots with such multimodal capabilities should have great applied value in material science. PMID:29316730

Randomized study of initial treatment with radiationter dot MCNU or radiationter dot MCNUter dot interferon-. beta. for malignant glioma

Energy Technology Data Exchange (ETDEWEB)

Kiya, Katsuzo; Uozumi, Tohru; Kurisu, Kaoru (Hiroshima Univ. (Japan). School of Medicine) (and others)

1990-02-01

The efficacy of radiation{center dot}MCNU (MR group) or radiation{center dot}MCNU{center dot}interferon-{beta} (IMR group) for malignant glioma was studied by a randomized trial at numerous medical facilities. MR group was irradiated with 50{approx}60 Gy and intravenously injected with 2 mg/kg of MCNU on the initial day of irradiation and 6 weeks later. IMR group was also given intravenous administration of interferon-{beta} at the dose of 2x10{sup 6}IU/m{sup 2} for 5 serial-days every eight weeks. There was no difference in background between the two groups. The response rate in MR group and IMR group was 44.4% (4/9) and 30.0% (3/10), respectively, showing no significant difference. The resected tumor volume before the start of these regimens seemed to correlate the response to the treatment in both groups. The major toxicity was myelosuppression, especially using MCNU with interferon-{beta}. These results indicated that this combined therapy is effective for malignant glioma, and should be executed further trials and follow up study. (author).

Vacuum-induced coherence in quantum dot systems

Science.gov (United States)

Sitek, Anna; Machnikowski, Paweł

2012-11-01

We present a theoretical study of vacuum-induced coherence in a pair of vertically stacked semiconductor quantum dots. The process consists in a coherent excitation transfer from a single-exciton state localized in one dot to a delocalized state in which the exciton occupation gets trapped. We study the influence of the factors characteristic of quantum dot systems (as opposed to natural atoms): energy mismatch, coupling between the single-exciton states localized in different dots, and different and nonparallel dipoles due to sub-band mixing, as well as coupling to phonons. We show that the destructive effect of the energy mismatch can be overcome by an appropriate interplay of the dipole moments and coupling between the dots which allows one to observe the trapping effect even in a structure with technologically realistic energy splitting of the order of milli-electron volts. We also analyze the impact of phonon dynamics on the occupation trapping and show that phonon effects are suppressed in a certain range of system parameters. This analysis shows that the vacuum-induced coherence effect and the associated long-living trapped excitonic population can be achieved in quantum dots.

Spin Switching via Quantum Dot Spin Valves

Science.gov (United States)

Gergs, N. M.; Bender, S. A.; Duine, R. A.; Schuricht, D.

2018-01-01

We develop a theory for spin transport and magnetization dynamics in a quantum dot spin valve, i.e., two magnetic reservoirs coupled to a quantum dot. Our theory is able to take into account effects of strong correlations. We demonstrate that, as a result of these strong correlations, the dot gate voltage enables control over the current-induced torques on the magnets and, in particular, enables voltage-controlled magnetic switching. The electrical resistance of the structure can be used to read out the magnetic state. Our model may be realized by a number of experimental systems, including magnetic scanning-tunneling microscope tips and artificial quantum dot systems.

Bright infrared LEDs based on colloidal quantum-dots

KAUST Repository

Sun, Liangfeng; Choi, Joshua J.; Stachnik, David; Bartnik, Adam C.; Hyun, Byung-Ryool; Malliaras, George G.; Hanrath, Tobias; Wise, Frank W.

2013-01-01

Record-brightness infrared LEDs based on colloidal quantum-dots have been achieved through control of the spacing between adjacent quantum-dots. By tuning the size of quantum-dots, the emission wavelengths can be tuned between 900nm and 1650nm. © 2013 Materials Research Society.

Sphere and dot product representations of graphs

NARCIS (Netherlands)

R.J. Kang (Ross); T. Müller (Tobias)

2012-01-01

textabstractA graph $G$ is a $k$-sphere graph if there are $k$-dimensional real vectors $v_1,\\dots,v_n$ such that $ij\\in E(G)$ if and only if the distance between $v_i$ and $v_j$ is at most $1$. A graph $G$ is a $k$-dot product graph if there are $k$-dimensional real vectors $v_1,\\dots,v_n$ such

Scalable quantum computer architecture with coupled donor-quantum dot qubits

Science.gov (United States)

Schenkel, Thomas; Lo, Cheuk Chi; Weis, Christoph; Lyon, Stephen; Tyryshkin, Alexei; Bokor, Jeffrey

2014-08-26

A quantum bit computing architecture includes a plurality of single spin memory donor atoms embedded in a semiconductor layer, a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, wherein a first voltage applied across at least one pair of the aligned quantum dot and donor atom controls a donor-quantum dot coupling. A method of performing quantum computing in a scalable architecture quantum computing apparatus includes arranging a pattern of single spin memory donor atoms in a semiconductor layer, forming a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, applying a first voltage across at least one aligned pair of a quantum dot and donor atom to control a donor-quantum dot coupling, and applying a second voltage between one or more quantum dots to control a Heisenberg exchange J coupling between quantum dots and to cause transport of a single spin polarized electron between quantum dots.

Influence of surface states of CuInS{sub 2} quantum dots in quantum dots sensitized photo-electrodes

Energy Technology Data Exchange (ETDEWEB)

Peng, Zhuoyin; Liu, Yueli [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070 (China); Wu, Lei [School of Electronic and Electrical, Wuhan Railway Vocational College of Technology, Wuhan 430205 (China); Zhao, Yinghan; Chen, Keqiang [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070 (China); Chen, Wen, E-mail: chenw@whut.edu.cn [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070 (China)

2016-12-01

Graphical abstract: J–V curves of different ligands capped CuInS{sub 2} QDs sensitized TiO{sub 2} photo-electrodes. - Highlights: • DDT, OLA, MPA, and S{sup 2−} ligand capped CuInS{sub 2} quantum dot sensitized photo-electrodes are prepared. • Surface states of quantum dots greatly influence the electrochemical performance of CuInS{sub 2} quantum dot sensitized photo-electrodes. • S{sup 2−} ligand enhances the UV–vis absorption and electron–hole separation property as well as the excellent charge transfer performance of the photo-electrodes. - Abstract: Surface states are significant factor for the enhancement of electrochemical performance in CuInS{sub 2} quantum dot sensitized photo-electrodes. DDT, OLA, MPA, and S{sup 2−} ligand capped CuInS{sub 2} quantum dot sensitized photo-electrodes are prepared by thermolysis, solvethermal and ligand-exchange processes, respectively, and their optical properties and photoelectrochemical properties are investigated. The S{sup 2−} ligand enhances the UV–vis absorption and electron–hole separation property as well as the excellent charge transfer performance of the photo-electrodes, which is attributed to the fact that the atomic S{sup 2−} ligand for the interfacial region of quantum dots may improve the electron transfer rate. These S{sup 2−}-capped CuInS{sub 2} quantum dot sensitized photo-electrodes exhibit the excellent photoelectrochemical efficiency and IPCE peak value, which is higher than that of the samples with DDT, OLA and MPA ligands.

Bracing can reduce high degree curves and improve aesthetics immediately after the end of growth. Final results of a retrospective case series.

Science.gov (United States)

Negrini, Stefano; Donzelli, Sabrina; Lusini, Monia; Zaina, Fabio

2012-01-01

Recently it has been shown that idiopathic scoliosis (IS) curves can be reduced with bracing, and it has been proposed that this could be useful in non-surgically treated high degree curves even after Risser 3. Moreover, bracing has been shown to be able to improve aesthetics, and this could be another reason to treat some patients with cosmetic needs. Our aim is to preliminary check if results can be obtained in IS patients after Risser 3. Design. Retrospective uncontrolled cohort study. Inclusion criteria. All IS patients treated on a voluntary basis for aesthetic reasons and/or for curve reduction; Risser 4-5 at start; end of treatment reached. Population. 34 females and 2 males, age 16.2±1.6 years, Cobb angle 27.6°±8.9°. Treatment. Lyon or SPoRT braces 18 to 24 hours/day, specific SEAS exercises, rapid weaning (2-3 hours every 6 months). Outcome criteria: SRS (unchanged; worsened over 6°; over 45° at the end of treatment; surgically treated), radiographic and clinical. Statistics. ANOVA and chi-test. The reported compliance during the 2.8 ± 1.1 treatment years was 95.1%, while residual growth was 0.9 ± 1.1 cm. Improvements were found in 39% of this cohort, (46% in curves over 30°). Only 1 patient progressed 6°. We found highly statistically significant reductions of maximal (-4.4°), thoracic (-6.0°) and thoracolumbar (-6.6°) curves. Statistically significant improvements were found for Aesthetic Index. Before 20 years of age, even in skeletally mature patients, it is possible to reach radiographic and aesthetic improvements, although not as good as during growth. Correction is based on bone growth, but ligaments and neuromuscular control of posture can also be involved.

Kondo and mixed-valence regimes in multilevel quantum dots

International Nuclear Information System (INIS)

Chudnovskiy, A. L.; Ulloa, S. E.

2001-01-01

We investigate the dependence of the ground state of a multilevel quantum dot on the coupling to an external fermionic system and on the interactions in the dot. As the coupling to the external system increases, the rearrangement of the effective energy levels in the dot signals the transition from the Kondo regime to a mixed-valence (MV) regime. The MV regime in a two-level dot is characterized by an intrinsic mixing of the levels in the dot, resulting in nonperturbative subtunneling and supertunneling phenomena that strongly influence the Kondo effect

Scintillation properties of quantum-dot doped styrene based plastic scintillators

International Nuclear Information System (INIS)

Park, J.M.; Kim, H.J.; Hwang, Y.S.; Kim, D.H.; Park, H.W.

2014-01-01

We fabricated quantum-dot doped plastic scintillators in order to control the emission wavelength. We studied the characterization of the quantum-dots (CdSe/ZnS) and PPO (2, 5-diphenyloxazole) doped styrene based plastic scintillators. PPO is usually used as a dopant to enhance the scintillation properties of organic scintillators with a maximum emission wavelength of 380 nm. In order to study the scintillation properties of the quantum-dots doped plastic scintillators, the samples were irradiated with X-ray, photon, and 45 MeV proton beams. We observed that only PPO doped plastic scintillators shows a luminescence peak around 380 nm. However, both the quantum-dots and PPO doped plastic scintillators shows luminescence peaks around 380 nm and 520 nm. Addition of quantum-dots had shifted the luminescence spectrum from 380 nm (PPO) toward the region of 520 nm (Quantum-dots). Emissions with wavelength controllable plastic scintillators can be matched to various kinds of photosensors such as photomultiplier tubes, photo-diodes, avalanche photo-diodes, and CCDs, etc. Also quantum-dots doped plastic scintillator, which is irradiated 45 MeV proton beams, shows that the light yield of quantum-dots doped plastic scintillator is increases as quantum-dots doping concentration increases at 520 nm. And also the plastic scintillators were irradiated with Cs-137 γ-ray for measuring fluorescence decay time. -- Highlights: • Quantum-dot doped plastic scintillator is grown by the thermal polymerization method. • Quantum-dot doped plastic scintillators can control the emission wavelength to match with photo-sensor. • Quantum-dots and PPO doped plastic scintillators emitted luminescence peaks around 380 nm and 520 nm. • We observed the energy transfer from PPO to quantum-dot in the quantum-dot doped plastic scintillator

Scintillation properties of quantum-dot doped styrene based plastic scintillators

Energy Technology Data Exchange (ETDEWEB)

Park, J.M.; Kim, H.J., E-mail: hongjooknu@gmail.com; Hwang, Y.S.; Kim, D.H.; Park, H.W.

2014-02-15

We fabricated quantum-dot doped plastic scintillators in order to control the emission wavelength. We studied the characterization of the quantum-dots (CdSe/ZnS) and PPO (2, 5-diphenyloxazole) doped styrene based plastic scintillators. PPO is usually used as a dopant to enhance the scintillation properties of organic scintillators with a maximum emission wavelength of 380 nm. In order to study the scintillation properties of the quantum-dots doped plastic scintillators, the samples were irradiated with X-ray, photon, and 45 MeV proton beams. We observed that only PPO doped plastic scintillators shows a luminescence peak around 380 nm. However, both the quantum-dots and PPO doped plastic scintillators shows luminescence peaks around 380 nm and 520 nm. Addition of quantum-dots had shifted the luminescence spectrum from 380 nm (PPO) toward the region of 520 nm (Quantum-dots). Emissions with wavelength controllable plastic scintillators can be matched to various kinds of photosensors such as photomultiplier tubes, photo-diodes, avalanche photo-diodes, and CCDs, etc. Also quantum-dots doped plastic scintillator, which is irradiated 45 MeV proton beams, shows that the light yield of quantum-dots doped plastic scintillator is increases as quantum-dots doping concentration increases at 520 nm. And also the plastic scintillators were irradiated with Cs-137 γ-ray for measuring fluorescence decay time. -- Highlights: • Quantum-dot doped plastic scintillator is grown by the thermal polymerization method. • Quantum-dot doped plastic scintillators can control the emission wavelength to match with photo-sensor. • Quantum-dots and PPO doped plastic scintillators emitted luminescence peaks around 380 nm and 520 nm. • We observed the energy transfer from PPO to quantum-dot in the quantum-dot doped plastic scintillator.

Quantum dots and nanocomposites.

Science.gov (United States)

Mansur, Herman Sander

2010-01-01

Quantum dots (QDs), also known as semiconducting nanoparticles, are promising zero-dimensional advanced materials because of their nanoscale size and because they can be engineered to suit particular applications such as nonlinear optical devices (NLO), electro-optical devices, and computing applications. QDs can be joined to polymers in order to produce nanocomposites which can be considered a scientific revolution of the 21st century. One of the fastest moving and most exciting interfaces of nanotechnology is the use of QDs in medicine, cell and molecular biology. Recent advances in nanomaterials have produced a new class of markers and probes by conjugating semiconductor QDs with biomolecules that have affinities for binding with selected biological structures. The nanoscale of QDs ensures that they do not scatter light at visible or longer wavelengths, which is important in order to minimize optical losses in practical applications. Moreover, at this scale, quantum confinement and surface effects become very important and therefore manipulation of the dot diameter or modification of its surface allows the properties of the dot to be controlled. Quantum confinement affects the absorption and emission of photons from the dot. Thus, the absorption edge of a material can be tuned by control of the particle size. This paper reviews developments in the myriad of possibilities for the use of semiconductor QDs associated with molecules producing novel hybrid nanocomposite systems for nanomedicine and bioengineering applications.

On the effect of the near field records on the steel braced frames equipped with energy dissipating devices

Directory of Open Access Journals (Sweden)

Mahmoud Bayat

Full Text Available The behavior of braced steel frame structures is of special importance due to its extensive use. Also the application of active and semi-active control systems, regarding to their benefits in obtaining better seismic performance has increased significantly. The majority of the works on steel structures and steel connections has been done under far field records, and the behavior of steel frame structures equipped with yielding dampers under these circumstances has not yet been fully analyzed. The main purpose of this paper is to determine the behavior of structures equipped with yielding dampers, located in near field based on energy concepts. In order to optimize their seismic behavior, the codes and solutions are also presented.The selected system is a braced steel frame system which is equipped with yielding dampers and the analysis is performed using the "Perform 3D V.4" software and the conclusions are drawn upon energy criterion. The effect of PGA variation and height of the frames are also considered in the study .Finally, using the above mentioned results, a proper solution is presented for typical systems in order to increase the energy damping ability and reduce the destructive effects in structures on an earthquake event, so that a great amount of induced energy is damped and destruction of the structure is prevented as much as possible.

Coherence and dephasing in self-assembled quantum dots

DEFF Research Database (Denmark)

Hvam, Jørn Märcher; Leosson, K.; Birkedal, Dan

2003-01-01

We measured dephasing times in InGaAl/As self-assembled quantum dots at low temperature using degenerate four-wave mixing. At 0K, the coherence time of the quantum dots is lifetime limited, whereas at finite temperatures pure dephasing by exciton-phonon interactions governs the quantum dot...

Transport through a vibrating quantum dot: Polaronic effects

International Nuclear Information System (INIS)

Koch, T; Alvermann, A; Fehske, H; Loos, J; Bishop, A R

2010-01-01

We present a Green's function based treatment of the effects of electron-phonon coupling on transport through a molecular quantum dot in the quantum limit. Thereby we combine an incomplete variational Lang-Firsov approach with a perturbative calculation of the electron-phonon self energy in the framework of generalised Matsubara Green functions and a Landauer-type transport description. Calculating the ground-state energy, the dot single-particle spectral function and the linear conductance at finite carrier density, we study the low-temperature transport properties of the vibrating quantum dot sandwiched between metallic leads in the whole electron-phonon coupling strength regime. We discuss corrections to the concept of an anti-adiabatic dot polaron and show how a deformable quantum dot can act as a molecular switch.

Optical power limiting in ensembles of colloidal Ag{sub 2}S quantum dots

Energy Technology Data Exchange (ETDEWEB)

Ovchinnikov, O V; Smirnov, M S; Perepelitsa, A S; Shatskikh, T S [Voronezh State University, Voronezh (Russian Federation); Shapiro, B I [M.V. Lomonosov Moscow State Academy of Fine Chemical Technology, Moscow (Russian Federation)

2015-12-31

The effect of power limiting for optical radiation at a wavelength of 660 nm with a pulse duration of 10 ms and operation threshold of 2.2 – 3.1 mJ cm{sup -2} is observed in ensembles of colloidal Ag{sub 2}S quantum dots (QDs). Using the z-scanning method in an open-aperture scheme it is found that the power is limited mainly due to reverse saturable absorption caused by two-photon optical transitions that involve energy levels of Ag{sub 2}S photoluminescence centres, related to structural impurity defects in colloidal Ag{sub 2}S QDs. At the same time, the z-scanning in a closed-aperture scheme demonstrates the formation of a thermal dynamic lens. (nonlinear optical phenomena)

Quantum Dots Coupled to a Superconductor

DEFF Research Database (Denmark)

Jellinggaard, Anders Robert

are tuned electrostatically. This includes tuning the odd occupation of the dot through a quantum phase transition, where it forms a singlet with excitations in the superconductor. We detail the fabrication of these bottom gated devices, which additionally feature ancillary sensor dots connected...

Blood-derived small Dot cells reduce scar in wound healing

International Nuclear Information System (INIS)

Kong, Wuyi; Li Shaowei; Longaker, Michael T.; Lorenz, H. Peter

2008-01-01

Wounds in fetal skin heal without scar, however the mechanism is unknown. We identified a novel group of E-cadherin positive cells in the blood of fetal and adult mice and named them 'Dot cells'. The percentage of Dot cells in E16.5 fetal mice blood is more than twenty times higher compared to adult blood. Dot cells also express integrin β1, CD184, CD34, CD13 low and Sca1 low , but not CD45, CD44, and CD117. Dot cells have a tiny dot shape between 1 and 7 μm diameters with fast proliferation in vitro. Most of the Dot cells remain positive for E-cadherin and integrin β1 after one month in culture. Transplantation of Dot cells to adult mice heals skin wounds with less scar due to reduced smooth muscle actin and collagen expression in the repair tissue. Tracking GFP-positive Dot cells demonstrates that Dot cells migrate to wounds and differentiate into dermal cells, which also express strongly to FGF-2, and later lose their GFP expression. Our results indicate that Dot cells are a group of previously unidentified cells that have strong wound healing effect. The mechanism of scarless wound healing in fetal skin is due to the presence of a large number of Dot cells

Fast synthesize ZnO quantum dots via ultrasonic method.

Science.gov (United States)

Yang, Weimin; Zhang, Bing; Ding, Nan; Ding, Wenhao; Wang, Lixi; Yu, Mingxun; Zhang, Qitu

2016-05-01

Green emission ZnO quantum dots were synthesized by an ultrasonic sol-gel method. The ZnO quantum dots were synthesized in various ultrasonic temperature and time. Photoluminescence properties of these ZnO quantum dots were measured. Time-resolved photoluminescence decay spectra were also taken to discover the change of defects amount during the reaction. Both ultrasonic temperature and time could affect the type and amount of defects in ZnO quantum dots. Total defects of ZnO quantum dots decreased with the increasing of ultrasonic temperature and time. The dangling bonds defects disappeared faster than the optical defects. Types of optical defects first changed from oxygen interstitial defects to oxygen vacancy and zinc interstitial defects. Then transformed back to oxygen interstitial defects again. The sizes of ZnO quantum dots would be controlled by both ultrasonic temperature and time as well. That is, with the increasing of ultrasonic temperature and time, the sizes of ZnO quantum dots first decreased then increased. Moreover, concentrated raw materials solution brought larger sizes and more optical defects of ZnO quantum dots. Copyright © 2015 Elsevier B.V. All rights reserved.

Thick-shell nanocrystal quantum dots

Science.gov (United States)

Hollingsworth, Jennifer A [Los Alamos, NM; Chen, Yongfen [Eugene, OR; Klimov, Victor I [Los Alamos, NM; Htoon, Han [Los Alamos, NM; Vela, Javier [Los Alamos, NM

2011-05-03

Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

Optical localization of quantum dots in tapered nanowires

DEFF Research Database (Denmark)

Østerkryger, Andreas Dyhl; Gregersen, Niels; Fons, Romain

2017-01-01

In this work we have measured the far-field emission patterns of In As quantum dots embedded in a GaAs tapered nanowire and used an open-geometry Fourier modal method for determining the radial position of the quantum dots by computing the far-field emission pattern for different quantum dot...

Ordered quantum-ring chains grown on a quantum-dot superlattice template

International Nuclear Information System (INIS)

Wu Jiang; Wang, Zhiming M.; Holmes, Kyland; Marega, Euclydes; Mazur, Yuriy I.; Salamo, Gregory J.

2012-01-01

One-dimensional ordered quantum-ring chains are fabricated on a quantum-dot superlattice template by molecular beam epitaxy. The quantum-dot superlattice template is prepared by stacking multiple quantum-dot layers and quantum-ring chains are formed by partially capping quantum dots. Partially capping InAs quantum dots with a thin layer of GaAs introduces a morphological change from quantum dots to quantum rings. The lateral ordering is introduced by engineering the strain field of a multi-layer InGaAs quantum-dot superlattice.

Detection of CdSe quantum dot photoluminescence for security label on paper

Energy Technology Data Exchange (ETDEWEB)

Isnaeni,, E-mail: isnaeni@lipi.go.id; Sugiarto, Iyon Titok [Research Center for Physics, Indonesian Institute of Science, Building 442 Puspiptek Serpong, South Tangerang, Banten, Indonesia 15314 (Indonesia); Bilqis, Ratu; Suseno, Jatmiko Endro [Department of Physics, Diponegoro University, Jl. Prof. Soedarto, Tembalang, Semarang, Indonesia 50275 (Indonesia)

2016-02-08

CdSe quantum dot has great potential in various applications especially for emitting devices. One example potential application of CdSe quantum dot is security label for anti-counterfeiting. In this work, we present a practical approach of security label on paper using one and two colors of colloidal CdSe quantum dot, which is used as stamping ink on various types of paper. Under ambient condition, quantum dot is almost invisible. The quantum dot security label can be revealed by detecting emission of quantum dot using photoluminescence and cnc machine. The recorded quantum dot emission intensity is then analyzed using home-made program to reveal quantum dot pattern stamp having the word ’RAHASIA’. We found that security label using quantum dot works well on several types of paper. The quantum dot patterns can survive several days and further treatment is required to protect the quantum dot. Oxidation of quantum dot that occurred during this experiment reduced the emission intensity of quantum dot patterns.

Semiconductor Quantum Dots with Photoresponsive Ligands.

Science.gov (United States)

Sansalone, Lorenzo; Tang, Sicheng; Zhang, Yang; Thapaliya, Ek Raj; Raymo, Françisco M; Garcia-Amorós, Jaume

2016-10-01

Photochromic or photocaged ligands can be anchored to the outer shell of semiconductor quantum dots in order to control the photophysical properties of these inorganic nanocrystals with optical stimulations. One of the two interconvertible states of the photoresponsive ligands can be designed to accept either an electron or energy from the excited quantum dots and quench their luminescence. Under these conditions, the reversible transformations of photochromic ligands or the irreversible cleavage of photocaged counterparts translates into the possibility to switch luminescence with external control. As an alternative to regulating the photophysics of a quantum dot via the photochemistry of its ligands, the photochemistry of the latter can be controlled by relying on the photophysics of the former. The transfer of excitation energy from a quantum dot to a photocaged ligand populates the excited state of the species adsorbed on the nanocrystal to induce a photochemical reaction. This mechanism, in conjunction with the large two-photon absorption cross section of quantum dots, can be exploited to release nitric oxide or to generate singlet oxygen under near-infrared irradiation. Thus, the combination of semiconductor quantum dots and photoresponsive ligands offers the opportunity to assemble nanostructured constructs with specific functions on the basis of electron or energy transfer processes. The photoswitchable luminescence and ability to photoinduce the release of reactive chemicals, associated with the resulting systems, can be particularly valuable in biomedical research and can, ultimately, lead to the realization of imaging probes for diagnostic applications as well as to therapeutic agents for the treatment of cancer.

DotFETs : MOSFETs strained by a Single SiGE dot in a Low-Temperature ELA Technology

NARCIS (Netherlands)

Biasotto, C.

2011-01-01

The work presented in this thesis was performed in the context of the European Sixth Framework Program FP6 project “Disposable Dot Field Effect Transistor for High Speed Si Integrated Circuits”, referred to as the D-DotFET project. The project had the goal of realizing strain-enhanced mobility in

Coherent radiation by quantum dots and magnetic nanoclusters

International Nuclear Information System (INIS)

Yukalov, V. I.; Yukalova, E. P.

2014-01-01

The assemblies of either quantum dots or magnetic nanoclusters are studied. It is shown that such assemblies can produce coherent radiation. A method is developed for solving the systems of nonlinear equations describing the dynamics of such assemblies. The method is shown to be general and applicable to systems of different physical nature. Despite mathematical similarities of dynamical equations, the physics of the processes for quantum dots and magnetic nanoclusters is rather different. In a quantum dot assembly, coherence develops due to the Dicke effect of dot interactions through the common radiation field. For a system of magnetic clusters, coherence in the spin motion appears due to the Purcell effect caused by the feedback action of a resonator. Self-organized coherent spin radiation cannot arise without a resonator. This principal difference is connected with the different physical nature of dipole forces between the objects. Effective dipole interactions between the radiating quantum dots, appearing due to photon exchange, collectivize the dot radiation. While the dipolar spin interactions exist from the beginning, yet before radiation, and on the contrary, they dephase spin motion, thus destroying the coherence of moving spins. In addition, quantum dot radiation exhibits turbulent photon filamentation that is absent for radiating spins

Four-Wave Mixing Spectroscopy of Quantum Dot Molecules

Science.gov (United States)

Sitek, A.; Machnikowski, P.

2007-08-01

We study theoretically the nonlinear four-wave mixing response of an ensemble of coupled pairs of quantum dots (quantum dot molecules). We discuss the shape of the echo signal depending on the parameters of the ensemble: the statistics of transition energies and the degree of size correlations between the dots forming the molecules.

Crystal structure, hydrogen bonding, and sup 8 sup 1 Br NQR of low-temperature phase of 4-aminopyridinium tetrabromoantimonate (3)

CERN Document Server

Hashimoto, M; Fuess, H; Svoboda, I; Ehrenberg, H

2003-01-01

The crystal structure of the low-temperature phase (LTP) of the title compound was determined at 220 K (monoclinic, P2 sub 1 sub / sub c). The 4-aminopyridinium cations (4-NH sub 2 C sub 5 H sub 4 NH sup +) were found to be ordered in LTP, while being severely disordered in the room-temperature phase (monoclinic, C2/c). The tetrabromoantimonate anions (SbBr sub 4 sup -) were incorporated into the infinite polyanion chains of irregular SbBr sub 6 octahedra with two-edges sharing. The trans-Br-Sb-Br moiety in the SbBr sub 4 sup - anion was approximately symmetric differing from the asymmetric Br-Sb centre dot centre dot centre dot Br moiety found in LTP of pyridinium tetrabromoantimonate (3). The N-H moieties in both of the pyridine ring and the amino (-NH sub 2) group participate in the formation of N-H centre dot centre dot centre dot Br hydrogen bonds. It was shown that the sup 8 sup 1 Br NQR spectrum of LTP is closely related to the anion structure and the hydrogen bonds. The distinctive anion structures, a...

Quantum dot devices for optical communications

DEFF Research Database (Denmark)

Mørk, Jesper

2005-01-01

-low threshold currents and amplifiers with record-high power levels. In this tutorial we will review the basic properties of quantum dots, emphasizing the properties which are important for laser and amplifier applications, as well as devices for all-optical signal processing. The high-speed properties....... The main property of semiconductor quantum dots compared to bulk material or even quantum well structures is the discrete nature of the allowed states, which means that inversion of the medium can be obtained for very low electron densities. This has led to the fabrication of quantum dot lasers with record...

Near-field strong coupling of single quantum dots.

Science.gov (United States)

Groß, Heiko; Hamm, Joachim M; Tufarelli, Tommaso; Hess, Ortwin; Hecht, Bert

2018-03-01

Strong coupling and the resultant mixing of light and matter states is an important asset for future quantum technologies. We demonstrate deterministic room temperature strong coupling of a mesoscopic colloidal quantum dot to a plasmonic nanoresonator at the apex of a scanning probe. Enormous Rabi splittings of up to 110 meV are accomplished by nanometer-precise positioning of the quantum dot with respect to the nanoresonator probe. We find that, in addition to a small mode volume of the nanoresonator, collective coherent coupling of quantum dot band-edge states and near-field proximity interaction are vital ingredients for the realization of near-field strong coupling of mesoscopic quantum dots. The broadband nature of the interaction paves the road toward ultrafast coherent manipulation of the coupled quantum dot-plasmon system under ambient conditions.

Solid-state cavity quantum electrodynamics using quantum dots

International Nuclear Information System (INIS)

Gerard, J.M.; Gayral, B.; Moreau, E.; Robert, I.; Abram, I.

2001-01-01

We review the recent development of solid-state cavity quantum electrodynamics using single self-assembled InAs quantum dots and three-dimensional semiconductor microcavities. We discuss first prospects for observing a strong coupling regime for single quantum dots. We then demonstrate that the strong Purcell effect observed for single quantum dots in the weak coupling regime allows us to prepare emitted photons in a given state (the same spatial mode, the same polarization). We present finally the first single-mode solid-state source of single photons, based on an isolated quantum dot in a pillar microcavity. This optoelectronic device, the first ever to rely on a cavity quantum electrodynamics effect, exploits both Coulomb interaction between trapped carriers in a single quantum dot and single mode photon tunneling in the microcavity. (author)

Quantum dot solar cells

CERN Document Server

Wu, Jiang

2013-01-01

The third generation of solar cells includes those based on semiconductor quantum dots. This sophisticated technology applies nanotechnology and quantum mechanics theory to enhance the performance of ordinary solar cells. Although a practical application of quantum dot solar cells has yet to be achieved, a large number of theoretical calculations and experimental studies have confirmed the potential for meeting the requirement for ultra-high conversion efficiency. In this book, high-profile scientists have contributed tutorial chapters that outline the methods used in and the results of variou

Diagnosis of TIA (DOT) score--design and validation of a new clinical diagnostic tool for transient ischaemic attack.

Science.gov (United States)

Dutta, Dipankar

2016-02-09

The diagnosis of Transient Ischaemic Attack (TIA) can be difficult and 50-60% of patients seen in TIA clinics turn out to be mimics. Many of these mimics have high ABCD2 scores and fill urgent TIA clinic slots inappropriately. A TIA diagnostic tool may help non-specialists make the diagnosis with greater accuracy and improve TIA clinic triage. The only available diagnostic score (Dawson et al) is limited in scope and not widely used. The Diagnosis of TIA (DOT) Score is a new and internally validated web and mobile app based diagnostic tool which encompasses both brain and retinal TIA. The score was derived retrospectively from a single centre TIA clinic database using stepwise logistic regression by backwards elimination to find the best model. An optimum cutpoint was obtained for the score. The derivation and validation cohorts were separate samples drawn from the years 2010/12 and 2013 respectively. Receiver Operating Characteristic (ROC) curves and area under the curve (AUC) were calculated and the diagnostic accuracy of DOT was compared to the Dawson score. A web and smartphone calculator were designed subsequently. The derivation cohort had 879 patients and the validation cohort 525. The final model had seventeen predictors and had an AUC of 0.91 (95% CI: 0.89-0.93). When tested on the validation cohort, the AUC for DOTS was 0.89 (0.86-0.92) while that of the Dawson score was 0.77 (0.73-0.81). The sensitivity and specificity of the DOT score were 89% (CI: 84%-93%) and 76% (70%-81%) respectively while those of the Dawson score were 83% (78%-88%) and 51% (45%-57%). Other diagnostic accuracy measures (DOT vs. Dawson) include positive predictive values (75% vs. 58%), negative predictive values (89% vs. 79%), positive likelihood ratios (3.67 vs. 1.70) and negative likelihood ratios (0.15 vs. 0.32). The DOT score shows promise as a diagnostic tool for TIA and requires independent external validation before it can be widely used. It could potentially improve the

Carbon "Quantum" Dots for Fluorescence Labeling of Cells.

Science.gov (United States)

Liu, Jia-Hui; Cao, Li; LeCroy, Gregory E; Wang, Ping; Meziani, Mohammed J; Dong, Yiyang; Liu, Yuanfang; Luo, Pengju G; Sun, Ya-Ping

2015-09-02

The specifically synthesized and selected carbon dots of relatively high fluorescence quantum yields were evaluated in their fluorescence labeling of cells. For the cancer cell lines, the cellular uptake of the carbon dots was generally efficient, resulting in the labeling of the cells with bright fluorescence emissions for both one- and two-photon excitations from predominantly the cell membrane and cytoplasm. In the exploration on labeling the live stem cells, the cellular uptake of the carbon dots was relatively less efficient, though fluorescence emissions could still be adequately detected in the labeled cells, with the emissions again predominantly from the cell membrane and cytoplasm. This combined with the observed more efficient internalization of the same carbon dots by the fixed stem cells might suggest some significant selectivity of the stem cells toward surface functionalities of the carbon dots. The needs and possible strategies for more systematic and comparative studies on the fluorescence labeling of different cells, including especially live stem cells, by carbon dots as a new class of brightly fluorescent probes are discussed.

The effect of near laterally and vertically neighboring quantum dots on the composition of uncapped InxGa1−xAs/GaAs quantum dots

International Nuclear Information System (INIS)

Donglin, Wang; Zhongyuan, Yu; Yumin, Liu; Han, Ye; Pengfei, Lu; Xiaotao, Guo; Long, Zhao; Xia, Xin

2010-01-01

The composition of quantum dots has a direct effect on the optical and electronic properties of quantum-dot-based devices. In this paper, we combine the method of moving asymptotes and finite element tools to compute the composition distribution by minimizing the Gibbs free energy of quantum dots, and use this method to study the effect of near laterally and vertically neighboring quantum dots on the composition distribution. The simulation results indicate that the effect from the laterally neighboring quantum dot is very small, and the vertically neighboring quantum dot can significantly influence the composition by the coupled strain field

Fabrication of quantum-dot devices in graphene

Directory of Open Access Journals (Sweden)

Satoshi Moriyama, Yoshifumi Morita, Eiichiro Watanabe, Daiju Tsuya, Shinya Uji, Maki Shimizu and Koji Ishibashi

2010-01-01

Full Text Available We describe our recent experimental results on the fabrication of quantum-dot devices in a graphene-based two-dimensional system. Graphene samples were prepared by micromechanical cleavage of graphite crystals on a SiO2/Si substrate. We performed micro-Raman spectroscopy measurements to determine the number of layers of graphene flakes during the device fabrication process. By applying a nanofabrication process to the identified graphene flakes, we prepared a double-quantum-dot device structure comprising two lateral quantum dots coupled in series. Measurements of low-temperature electrical transport show the device to be a series-coupled double-dot system with varied interdot tunnel coupling, the strength of which changes continuously and non-monotonically as a function of gate voltage.

Enhanced Photoelectrochemical Response of Zn-Dotted Hematite

Directory of Open Access Journals (Sweden)

Saroj Kumari

2007-01-01

Full Text Available Photoelectrochemical response of thin films of α-Fe2O3, Zn doped α-Fe2O3, and Zn dots deposited on doped α-Fe2O3 prepared by spray pyrolysis has been studied. Samples of Zn dots were prepared using thermal evaporation method by evaporating Zn through a mesh having pore diameter of 0.7 mm. The presence of Zn-dotted islands on doped α-Fe2O3 surface exhibited significantly large photocurrent density as compared to other samples. An optimum thickness of Zn dots ∼230 Å is found to give enhanced photoresponse. The observed results are analyzed with the help of estimated values of resistivity, band gap, flatband potential, and donor density.

From quantum dots to quantum circuits

International Nuclear Information System (INIS)

Ensslin, K.

2008-01-01

Full text: Quantum dots, or artificial atoms, confine charge carriers in three-dimensional islands in a semiconductor environment. Detailed understanding and exquisite control of the charge and spin state of the electrically tunable charge occupancy have been demonstrated over the years. Quantum dots with best quality for transport experiments are usually realized in n-type AlGaAs/GaAs heterostructures. Novel material systems, such as graphene, nanowires and p-type heterostructures offer unexplored parameter regimes in view of spin-orbit interactions, carrier-carrier interactions and hyperfine coupling between electron and nuclear spins, which might be relevant for future spin qubits realized in quantum dots. With more sophisticated nanotechnology it has become possible to fabricate coupled quantum systems where classical and quantum mechanical coupling and back action is experimentally investigated. A narrow constriction, or quantum point contact, in vicinity to a quantum dot has been shown to serve as a minimally invasive sensor of the charge state of the dot. If charge transport through the quantum dot is slow enough (kHz), the charge sensor allows the detection of time-resolved transport through quantum-confined structures. This has allowed us to measure extremely small currents not detectable with conventional electronics. In addition the full statistics of current fluctuations becomes experimentally accessible. This way correlations between electrons which influence the current flow can be analyzed by measuring the noise and higher moments of the distribution of current fluctuations. Mesoscopic conductors driven out of equilibrium can emit photons which may be detected by another nearby quantum system with suitably tuned energy levels. This way an on-chip microwave single photon detector has been realized. In a ring geometry containing a tunable double quantum dot it has been possible to measure the self-interference of individual electrons as they traverse

Double quantum dot as a minimal thermoelectric generator

OpenAIRE

Donsa, S.; Andergassen, S.; Held, K.

2014-01-01

Based on numerical renormalization group calculations, we demonstrate that experimentally realized double quantum dots constitute a minimal thermoelectric generator. In the Kondo regime, one quantum dot acts as an n-type and the other one as a p-type thermoelectric device. Properly connected the double quantum dot provides a miniature power supply utilizing the thermal energy of the environment.

Circularly organized quantum dot nanostructures of Ge on Si substrates

International Nuclear Information System (INIS)

Cai, Qijia; Chen, Peixuan; Zhong, Zhenyang; Jiang, Zuimin; Lu, Fang; An, Zhenghua

2009-01-01

A novel circularly arranged structure of germanium quantum dots has been fabricated by combining techniques including electron beam lithography, wet etching and molecular beam epitaxy. It was observed that both pattern and growth parameters affect the morphology of the quantum dot molecules. Meanwhile, the oxidation mask plays a vital role in the formation of circularly organized quantum dots. The experimental results demonstrate the possibilities of investigating the properties of quantum dot molecules as well as single quantum dots

First principles study of edge carboxylated graphene quantum dots

Science.gov (United States)

Abdelsalam, Hazem; Elhaes, Hanan; Ibrahim, Medhat A.

2018-05-01

The structure stability and electronic properties of edge carboxylated hexagonal and triangular graphene quantum dots are investigated using density functional theory. The calculated binding energies show that the hexagonal clusters with armchair edges have the highest stability among all the quantum dots. The binding energy of carboxylated graphene quantum dots increases by increasing the number of carboxyl groups. Our study shows that the total dipole moment significantly increases by adding COOH with the highest value observed in triangular clusters. The edge states in triangular graphene quantum dots with zigzag edges produce completely different energy spectrum from other dots: (a) the energy gap in triangular zigzag is very small as compared to other clusters and (b) the highest occupied molecular orbital is localized at the edges which is in contrast to other clusters where it is distributed over the cluster surface. The enhanced reactivity and the controllable energy gap by shape and edge termination make graphene quantum dots ideal for various nanodevice applications such as sensors. The infrared spectra are presented to confirm the stability of the quantum dots.

Photoemission Studies of Si Quantum Dots with Ge Core: Dots formation, Intermixing at Si-clad/Ge-core interface and Quantum Confinement Effect

Directory of Open Access Journals (Sweden)

Yudi Darma

2008-03-01

Full Text Available Spherical Si nanocrystallites with Ge core (~20nm in average dot diameter have been prepared by controlling selective growth conditions of low-pressure chemical vapor deposition (LPCVD on ultrathin SiO2 using alternately pure SiH4 and 5% GeH4 diluted with He. XPS results confirm the highly selective growth of Ge on the pregrown Si dots and subsequently complete coverage by Si selective growth on Ge/Si dots. Compositional mixing and the crystallinity of Si dots with Ge core as a function of annealing temperature in the range of 550-800oC has been evaluated by XPS analysis and confirms the diffusion of Ge atoms from Ge core towards the Si clad accompanied by formation of GeOx at the Si clad surface. The first subband energy at the valence band of Si dot with Ge core has been measured as an energy shift at the top of the valence band density of state using XPS. The systematic shift of the valence band maximum towards higher binding energy with progressive deposition in the dot formation indicate the charging effect of dots and SiO2 layer by photoemission during measurements.

Photoluminescence studies of single InGaAs quantum dots

DEFF Research Database (Denmark)

Leosson, Kristjan; Jensen, Jacob Riis; Hvam, Jørn Märcher

1999-01-01

Semiconductor quantum dots are considered a promising material system for future optical devices and quantum computers. We have studied the low-temperature photoluminescence properties of single InGaAs quantum dots embedded in GaAs. The high spatial resolution required for resolving single dots...... to resolve luminescence lines from individual quantum dots, revealing an atomic-like spectrum of sharp transition lines. A parameter of fundamental importance is the intrinsic linewidth of these transitions. Using high-resolution spectroscopy we have determined the linewidth and investigated its dependence...... on temperature, which gives information about how the exciton confined to the quantum dot interacts with the surrounding lattice....

Coulomb Blockade of Tunnel-Coupled Quantum Dots

National Research Council Canada - National Science Library

Golden, John

1997-01-01

.... Though classical charging models can explain the Coulomb blockade of an isolated dot, they must be modified to explain the Coulomb blockade of dots coupled through the quantum mechanical tunneling of electrons...

Optical Properties of Semiconductor Quantum Dots

NARCIS (Netherlands)

Perinetti, U.

2011-01-01

This thesis presents different optical experiments performed on semiconductor quantum dots. These structures allow to confine a small number of electrons and holes to a tiny region of space, some nm across. The aim of this work was to study the basic properties of different types of quantum dots

Realization of electrically tunable single quantum dot nanocavities

Energy Technology Data Exchange (ETDEWEB)

Hofbauer, Felix Florian Georg

2009-03-15

We investigated the design, fabrication and optical investigation of electrically tunable single quantum dot-photonic crystal defect nanocavities operating in both the weak and strong coupling regimes of the light matter interaction. We demonstrate that the quantum confined Stark effect can be employed to quickly and reversibly switch the dot-cavity coupling, simply by varying a gate voltage. Our results show that exciton transitions from individual dots can be tuned by up to {proportional_to}4 meV relative to the nanocavity mode, before the emission quenches due to carrier tunneling escape from the dots. We directly probe spontaneous emission, irreversible polariton decay and the statistics of the emitted photons from a single-dot nanocavity in the weak and strong coupling regimes. New information is obtained on the nature of the dot-cavity coupling in the weak coupling regime and electrical control of zero dimensional polaritons is demonstrated for the first time. The structures investigated are p-i-n photodiodes consisting of an 180nm thick free-standing GaAs membrane into which a two dimensional photonic crystal is formed by etching a triangular lattice of air holes. Low mode volume nanocavities (V{sub mode}<1.6 ({lambda}/n){sup 3}) are realized by omitting 3 holes in a line to form L3 cavities and a single layer of InGaAs self-assembled quantum dots is embedded into the midpoint of the membrane. The nanocavities are electrically contacted via 35 nm thick p- and n-doped contact layers in the GaAs membrane. In the weak coupling regime, time resolved spectroscopy reveals a {proportional_to}7 x shortening of the spontaneous emission lifetime as the dot is tuned through the nanocavity mode, due to the Purcell effect. Upon strongly detuning the same quantum dot transition from the nanocavity mode we observe an additional {proportional_to}8 x lengthening of the spontaneous emission lifetime. These observations unequivocally highlight two regimes of dot

Shape, strain, and ordering of lateral InAs quantum dot molecules

International Nuclear Information System (INIS)

Krause, B.; Metzger, T.H.; Rastelli, A.; Songmuang, R.; Kiravittaya, S.; Schmidt, O. G.

2005-01-01

The results of an x-ray study on freestanding, self-assembled InAs/GaAs quantum dots grown by molecular beam epitaxy are presented. The studied samples cover the range from statistically distributed single quantum dots to quantum dot bimolecules, and finally to quantum dot quadmolecules. The x-ray diffraction data of the single quantum dots and the bimolecules, obtained in grazing incidence geometry, have been analyzed using the isostrain model. An extended version of the isostrain model has been developed, including the lateral arrangement of the quantum dots within a quantum dot molecule and the superposition of the scattering from different parts of the dots. This model has been applied to the scattering maps of all three samples. Quantitative information about the positions of the dots, the shape, and the lattice parameter distribution of their crystalline core has been obtained. For the single dot and the bimolecule, a strong similarity of the shape and lattice parameter distribution has been found, in agreement with the similarity of their photoluminescence spectra

Photoinduced electric dipole in CuCl quantum dots

International Nuclear Information System (INIS)

Masumoto, Yasuaki; Naruse, Fumitaka; Kanno, Atsushi

2003-01-01

Electromodulated absorption spectra of CuCl quantum dots modulated at twice the modulation frequency of electric field, 2f, show prominent structure around persistently burned hole. It grows in proportion to square of the electric field in the same manner as the 2f component of electromodulated absorption spectra of the dots without the laser exposure. Even the f component of electromodulated signal was observed around the burned hole position. These observations are explained by considering electric dipole formed in hole burned and photoionized quantum dots. Photoionization not only produces persistent spectral hole burning but also the local built-in electric field and photoinduced dipole moment in quantum dots. The dipole moment is estimated to be about 5 debye for 3.2-nm-radius quantum dots. The dipole moments are randomly oriented but 1% anisotropy is deduced from the electromodulated signal at f

Using biharmonic laser pumping for preparation of pure and entangled multiexciton states in clusters of resonantly interacting fluorescent centres

International Nuclear Information System (INIS)

Basieva, I.T.; Basiev, T.T.; Dietler, G.; Pukhov, K.K.; Sekatskii, S.K.

2007-01-01

Use of a biharmonic laser pumping for preparation of pure and entangled multiexciton states in dimers and tetramers of resonantly interacting fluorescent particles is analysed. Special emphasis is given to the preparation of all possible pure exciton states and their maximally entangled Bell states. The general results are illustrated using as an example the pair and quartet centres of neodymium ions in calcium fluoride (M- and N-centres), where all necessary experimental information concerning the interactions and decoherence is available, and experimental preparation of Bell vacuum-single exciton and vacuum-biexciton states has been recently demonstrated. These results can be easily rescaled for the cases of quantum dots and dye molecules. Numerical results are compared with the analytical results obtained for a particular case of the biharmonic excitation of dimers. Excellent agreement between these approaches is demonstrated

Numerical Model of a Hybrid Damping System Composed of a Buckling Restrained Brace with a Magneto Rheological Damper

Directory of Open Access Journals (Sweden)

Filip-Vacarescu Norin

2016-03-01

Full Text Available This paper discusses the concept of a hybrid damper made from a combination of two dissipative devices. A passive hysteretic device like steel Buckling Restrained Brace (BRB can be combined with a magneto-rheological (MR Fluid Damper in order to obtain a hybrid dissipative system. This system can work either as a semi-active system, if the control unit is available, or as a passive system, tuned for working according to performance based seismic engineering (PBSE scale of reference parameters (i.e. interstory drift.

Micromagnetic simulations of submicron cobalt dots

International Nuclear Information System (INIS)

Parker, G. J.; Cerjan, C.

2000-01-01

Numerical simulations of submicron Co extruded elliptical dots were performed to illustrate the relative importance of different physical parameters on the switching behavior in the easy direction. Shape, size, magnetic moment magnitude, and the magnitude and distribution of the crystalline anisotropicity were varied. The simulation represents magnetostatic, exchange, and crystalline anisotropicity fields on a structured mesh using finite difference techniques. The smooth boundary of the dots is accurately represented by use of the embedded curve boundary method. Agreement with experimental hysteresis measurements of submicron dot arrays is obtained when an appropriate angular distribution of the grain anisotropicity axes is invoked. (c) 2000 American Institute of Physics

Photoemission Studies of Si Quantum Dots with Ge Core: Dots formation, Intermixing at Si-clad/Ge-core interface and Quantum Confinement Effect

OpenAIRE

Yudi Darma

2008-01-01

Spherical Si nanocrystallites with Ge core (~20nm in average dot diameter) have been prepared by controlling selective growth conditions of low-pressure chemical vapor deposition (LPCVD) on ultrathin SiO2 using alternately pure SiH4 and 5% GeH4 diluted with He. XPS results confirm the highly selective growth of Ge on the pregrown Si dots and subsequently complete coverage by Si selective growth on Ge/Si dots. Compositional mixing and the crystallinity of Si dots with Ge core as a function of ...

Central dot sign in entities other than Caroli disease

International Nuclear Information System (INIS)

Ahmadi, T.; Itai, Yuji; Minami, Manabu.

1997-01-01

The purpose of this study was to describe central dot sign (tiny dots with strong contrast enhancement of the portal vein within dilated hepatic bile ducts on computed tomography) in entities other than Caroli disease, especially in peribiliary cysts with or without autosomal-dominant polycystic kidney disease. Computed tomography in 74 cases of peribiliary cysts and 134 cases of other liver diseases and states possibly showing central dot sign were retrospectively reviewed to examine the central dot sign. In three cases of peribiliary cysts, some part of the liver showed strongly enhanced portal radicles surrounded completely or partially by low-attenuation, enlarged peribiliary cysts, presenting ''central dot sign'' on contrast-enhanced computed tomography. We suggest that in addition to Caroli disease, some other entities and diseases of the liver may demonstrate central dot sign and this sign should not be considered a specific finding of Caroli disease. (author)

Central dot sign in entities other than Caroli disease