AUV (Autonomous Underwater Vehicle) Dive Control System Development Including Sensor Bias Compensation and Parameter Estimation

DTIC Science & Technology

1988-12-01

equations, x(k+l) = A*x(k) + B*u(k) + Ko *[y(k)-C*x(k)] in which y(k) is the previous time sensor output signals. In this case, two outputs were...available to the observer, the pitch rate, and the water depth. The observer gains, Ko , may be selected by using the dual of the controller pole placement...becomes, 15 y(k) = [l;l]*ye(k) so that the gains for the two-input system become Ko = [l;l]*ke where Ke are found via pole placement using ye(k). The

A conformal mapping based fractional order approach for sub-optimal tuning of PID controllers with guaranteed dominant pole placement

NASA Astrophysics Data System (ADS)

Saha, Suman; Das, Saptarshi; Das, Shantanu; Gupta, Amitava

2012-09-01

A novel conformal mapping based fractional order (FO) methodology is developed in this paper for tuning existing classical (Integer Order) Proportional Integral Derivative (PID) controllers especially for sluggish and oscillatory second order systems. The conventional pole placement tuning via Linear Quadratic Regulator (LQR) method is extended for open loop oscillatory systems as well. The locations of the open loop zeros of a fractional order PID (FOPID or PIλDμ) controller have been approximated in this paper vis-à-vis a LQR tuned conventional integer order PID controller, to achieve equivalent integer order PID control system. This approach eases the implementation of analog/digital realization of a FOPID controller with its integer order counterpart along with the advantages of fractional order controller preserved. It is shown here in the paper that decrease in the integro-differential operators of the FOPID/PIλDμ controller pushes the open loop zeros of the equivalent PID controller towards greater damping regions which gives a trajectory of the controller zeros and dominant closed loop poles. This trajectory is termed as "M-curve". This phenomena is used to design a two-stage tuning algorithm which reduces the existing PID controller's effort in a significant manner compared to that with a single stage LQR based pole placement method at a desired closed loop damping and frequency.

Design of optimally normal minimum gain controllers by continuation method

NASA Technical Reports Server (NTRS)

Lim, K. B.; Juang, J.-N.; Kim, Z. C.

1989-01-01

A measure of the departure from normality is investigated for system robustness. An attractive feature of the normality index is its simplicity for pole placement designs. To allow a tradeoff between system robustness and control effort, a cost function consisting of the sum of a norm of weighted gain matrix and a normality index is minimized. First- and second-order necessary conditions for the constrained optimization problem are derived and solved by a Newton-Raphson algorithm imbedded into a one-parameter family of neighboring zero problems. The method presented allows the direct computation of optimal gains in terms of robustness and control effort for pole placement problems.

ONCO-TESE: Obtaining spermatozoa after radical orchiectomy for testicular tumour and azoospermia.

PubMed

Luján, S; Guzman-Ordaz, D; Rogel, R; Broseta, E; Pellicer, A; Boronat, F

2016-01-01

There is the possibility of diagnosing azoospermia in cases of testicular tumours in patients who wish to preserve fertility. Our objective is to present a technique for obtaining spermatozoa from testicles with ex vivo tumours in order to preserve fertility in these patients. A 34-year-old patient was referred for azoospermia. The physical examination revealed a node in the lower pole of the left testicle. In the scrotal ultrasound, the testicle presented disperse microcalcifications and a 1-cm hypoechoic mass in the lower pole. The tumour markers were negative, and the CT showed no distant disease. Left radical orchiectomy was performed, along with the placement of a testis prosthesis. Bench surgery was then performed, with extraction of the seminiferous tubules in the upper pole. Of the submitted samples, 4 progressive and 1 nonprogressive motile spermatozoa were identified per field. Two samples were cryopreserved. The pathological report indicated the presence of a seminoma measuring 1.3 × 1 cm, with free margins and with no invasion of the rete testis (stage I). An assisted reproduction technique (intracytoplasmic sperm injection) was performed on the patient's partner with the frozen spermatozoa, which resulted in pregnancy and the subsequent birth of a healthy child. We propose this technique as the method of choice for obtaining spermatozoa from patients who simultaneously present azoospermia and testicular tumours and who wish to preserve their fertility. Copyright © 2015 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

On the use and computation of the Jordan canonical form in system theory

NASA Technical Reports Server (NTRS)

Sridhar, B.; Jordan, D.

1974-01-01

This paper investigates various aspects of the application of the Jordan canonical form of a matrix in system theory and develops a computational approach to determining the Jordan form for a given matrix. Applications include pole placement, controllability and observability studies, serving as an intermediate step in yielding other canonical forms, and theorem proving. The computational method developed in this paper is both simple and efficient. The method is based on the definition of a generalized eigenvector and a natural extension of Gauss elimination techniques. Examples are included for demonstration purposes.

Recent results on output feedback problems

NASA Technical Reports Server (NTRS)

Byrnes, C. I.

1980-01-01

Given a real linear system sigma = (A, B, C) with m inputs, p outputs and degree n, the problem of generic pole placement by output feedback is studied, which is to compute the constant C(m,p) such that the inequality C(m,p) not less than n is necessary and sufficient for generically positioning the poles of the generic linear system by constant output feedback. A constant C prime (m,p) is determined, which gives a sufficient condition for generic pole placement and which, to the best of the author's knowledge, is at least as good an estimate of C(m,p) as any in the literature. Some results on the construction of solutions in case mp = n are announced, based on the degree formula of Brockett and Byrnes and the Galois theory. In particular, a question raised by Anderson, Bose, and Jury, on the existence of a rational procedure for computing the feedback law from the desired characteristic polynomial is answered.

Self-tuning multivariable pole placement control of a multizone crystal growth furnace

NASA Technical Reports Server (NTRS)

Batur, C.; Sharpless, R. B.; Duval, W. M. B.; Rosenthal, B. N.

1992-01-01

This paper presents the design and implementation of a multivariable self-tuning temperature controller for the control of lead bromide crystal growth. The crystal grows inside a multizone transparent furnace. There are eight interacting heating zones shaping the axial temperature distribution inside the furnace. A multi-input, multi-output furnace model is identified on-line by a recursive least squares estimation algorithm. A multivariable pole placement controller based on this model is derived and implemented. Comparison between single-input, single-output and multi-input, multi-output self-tuning controllers demonstrates that the zone-to-zone interactions can be minimized better by a multi-input, multi-output controller design. This directly affects the quality of crystal grown.

Variable Bone Density of Scaphoid: Importance of Subchondral Screw Placement.

PubMed

Swanstrom, Morgan M; Morse, Kyle W; Lipman, Joseph D; Hearns, Krystle A; Carlson, Michelle G

2018-02-01

Background  Ideal internal fixation of the scaphoid relies on adequate bone stock for screw purchase; so, knowledge of regional bone density of the scaphoid is crucial. Questions/Purpose  The purpose of this study was to evaluate regional variations in scaphoid bone density. Materials and Methods  Three-dimensional CT models of fractured scaphoids were created and sectioned into proximal/distal segments and then into quadrants (volar/dorsal/radial/ulnar). Concentric shells in the proximal and distal pole were constructed in 2-mm increments moving from exterior to interior. Bone density was measured in Hounsfield units (HU). Results  Bone density of the distal scaphoid (453.2 ± 70.8 HU) was less than the proximal scaphoid (619.8 ± 124.2 HU). There was no difference in bone density between the four quadrants in either pole. In both the poles, the first subchondral shell was the densest. In both the proximal and distal poles, bone density decreased significantly in all three deeper shells. Conclusion  The proximal scaphoid had a greater density than the distal scaphoid. Within the poles, there was no difference in bone density between the quadrants. The subchondral 2-mm shell had the greatest density. Bone density dropped off significantly between the first and second shell in both the proximal and distal scaphoids. Clinical Relevance  In scaphoid fracture ORIF, optimal screw placement engages the subchondral 2-mm shell, especially in the distal pole, which has an overall lower bone density, and the second shell has only two-third the density of the first shell.

Large planar maneuvers for articulated flexible manipulators

NASA Technical Reports Server (NTRS)

Huang, Jen-Kuang; Yang, Li-Farn

1988-01-01

An articulated flexible manipulator carried on a translational cart is maneuvered by an active controller to perform certain position control tasks. The nonlinear dynamics of the articulated flexible manipulator are derived and a transformation matrix is formulated to localize the nonlinearities within the inertia matrix. Then a feedback linearization scheme is introduced to linearize the dynamic equations for controller design. Through a pole placement technique, a robust controller design is obtained by properly assigning a set of closed-loop desired eigenvalues to meet performance requirements. Numerical simulations for the articulated flexible manipulators are given to demonstrate the feasibility and effectiveness of the proposed position control algorithms.

Optimal Robust Motion Controller Design Using Multiobjective Genetic Algorithm

PubMed Central

Svečko, Rajko

2014-01-01

This paper describes the use of a multiobjective genetic algorithm for robust motion controller design. Motion controller structure is based on a disturbance observer in an RIC framework. The RIC approach is presented in the form with internal and external feedback loops, in which an internal disturbance rejection controller and an external performance controller must be synthesised. This paper involves novel objectives for robustness and performance assessments for such an approach. Objective functions for the robustness property of RIC are based on simple even polynomials with nonnegativity conditions. Regional pole placement method is presented with the aims of controllers' structures simplification and their additional arbitrary selection. Regional pole placement involves arbitrary selection of central polynomials for both loops, with additional admissible region of the optimized pole location. Polynomial deviation between selected and optimized polynomials is measured with derived performance objective functions. A multiobjective function is composed of different unrelated criteria such as robust stability, controllers' stability, and time-performance indexes of closed loops. The design of controllers and multiobjective optimization procedure involve a set of the objectives, which are optimized simultaneously with a genetic algorithm—differential evolution. PMID:24987749

FtsZ Placement in Nucleoid-Free Bacteria

PubMed Central

Pazos, Manuel; Casanova, Mercedes; Palacios, Pilar; Margolin, William; Natale, Paolo; Vicente, Miguel

2014-01-01

We describe the placement of the cytoplasmic FtsZ protein, an essential component of the division septum, in nucleoid-free Escherichia coli maxicells. The absence of the nucleoid is accompanied in maxicells by degradation of the SlmA protein. This protein, together with the nucleoid, prevents the placement of the septum in the regions occupied by the chromosome by a mechanism called nucleoid occlusion (NO). A second septum placement mechanism, the MinCDE system (Min) involving a pole-to-pole oscillation of three proteins, nonetheless remains active in maxicells. Both Min and NO act on the polymerization of FtsZ, preventing its assembly into an FtsZ-ring except at midcell. Our results show that even in the total absence of NO, Min oscillations can direct placement of FtsZ in maxicells. Deletion of the FtsZ carboxyl terminal domain (FtsZ*), a central hub that receives signals from a variety of proteins including MinC, FtsA and ZipA, produces a Min-insensitive form of FtsZ unable to interact with the membrane-anchoring FtsA and ZipA proteins. This protein produces a totally disorganized pattern of FtsZ localization inside the maxicell cytoplasm. In contrast, FtsZ*-VM, an artificially cytoplasmic membrane-anchored variant of FtsZ*, forms helical or repetitive ring structures distributed along the entire length of maxicells even in the absence of NO. These results show that membrane anchoring is needed to organize FtsZ into rings and underscore the role of the C-terminal hub of FtsZ for their correct placement. PMID:24638110

FtsZ placement in nucleoid-free bacteria.

PubMed

Pazos, Manuel; Casanova, Mercedes; Palacios, Pilar; Margolin, William; Natale, Paolo; Vicente, Miguel

2014-01-01

We describe the placement of the cytoplasmic FtsZ protein, an essential component of the division septum, in nucleoid-free Escherichia coli maxicells. The absence of the nucleoid is accompanied in maxicells by degradation of the SlmA protein. This protein, together with the nucleoid, prevents the placement of the septum in the regions occupied by the chromosome by a mechanism called nucleoid occlusion (NO). A second septum placement mechanism, the MinCDE system (Min) involving a pole-to-pole oscillation of three proteins, nonetheless remains active in maxicells. Both Min and NO act on the polymerization of FtsZ, preventing its assembly into an FtsZ-ring except at midcell. Our results show that even in the total absence of NO, Min oscillations can direct placement of FtsZ in maxicells. Deletion of the FtsZ carboxyl terminal domain (FtsZ*), a central hub that receives signals from a variety of proteins including MinC, FtsA and ZipA, produces a Min-insensitive form of FtsZ unable to interact with the membrane-anchoring FtsA and ZipA proteins. This protein produces a totally disorganized pattern of FtsZ localization inside the maxicell cytoplasm. In contrast, FtsZ*-VM, an artificially cytoplasmic membrane-anchored variant of FtsZ*, forms helical or repetitive ring structures distributed along the entire length of maxicells even in the absence of NO. These results show that membrane anchoring is needed to organize FtsZ into rings and underscore the role of the C-terminal hub of FtsZ for their correct placement.

Differential-Drive Mobile Robot Control Design based-on Linear Feedback Control Law

NASA Astrophysics Data System (ADS)

Nurmaini, Siti; Dewi, Kemala; Tutuko, Bambang

2017-04-01

This paper deals with the problem of how to control differential driven mobile robot with simple control law. When mobile robot moves from one position to another to achieve a position destination, it always produce some errors. Therefore, a mobile robot requires a certain control law to drive the robot’s movement to the position destination with a smallest possible error. In this paper, in order to reduce position error, a linear feedback control is proposed with pole placement approach to regulate the polynoms desired. The presented work leads to an improved understanding of differential-drive mobile robot (DDMR)-based kinematics equation, which will assist to design of suitable controllers for DDMR movement. The result show by using the linier feedback control method with pole placement approach the position error is reduced and fast convergence is achieved.

Groebner Basis Solutions to Satellite Trajectory Control by Pole Placement

NASA Astrophysics Data System (ADS)

Kukelova, Z.; Krsek, P.; Smutny, V.; Pajdla, T.

2013-09-01

Satellites play an important role, e.g., in telecommunication, navigation and weather monitoring. Controlling their trajectories is an important problem. In [1], an approach to the pole placement for the synthesis of a linear controller has been presented. It leads to solving five polynomial equations in nine unknown elements of the state space matrices of a compensator. This is an underconstrained system and therefore four of the unknown elements need to be considered as free parameters and set to some prior values to obtain a system of five equations in five unknowns. In [1], this system was solved for one chosen set of free parameters with the help of Dixon resultants. In this work, we study and present Groebner basis solutions to this problem of computation of a dynamic compensator for the satellite for different combinations of input free parameters. We show that the Groebner basis method for solving systems of polynomial equations leads to very simple solutions for all combinations of free parameters. These solutions require to perform only the Gauss-Jordan elimination of a small matrix and computation of roots of a single variable polynomial. The maximum degree of this polynomial is not greater than six in general but for most combinations of the input free parameters its degree is even lower. [1] B. Palancz. Application of Dixon resultant to satellite trajectory control by pole placement. Journal of Symbolic Computation, Volume 50, March 2013, Pages 79-99, Elsevier.

Magnetic design and method of a superconducting magnet for muon g - 2/EDM precise measurements in a cylindrical volume with homogeneous magnetic field

NASA Astrophysics Data System (ADS)

Abe, M.; Murata, Y.; Iinuma, H.; Ogitsu, T.; Saito, N.; Sasaki, K.; Mibe, T.; Nakayama, H.

2018-05-01

A magnetic field design method of magneto-motive force (coil block (CB) and iron yoke) placements for g - 2/EDM measurements has been developed and a candidate placements were designed under superconducting limitations of current density 125 A/mm2 and maximum magnetic field on CBs less than 5.5 T. Placements of CBs and an iron yoke with poles were determined by tuning SVD (singular value decomposition) eigenmode strengths. The SVD was applied on a response matrix from magneto-motive forces to the magnetic fields in the muon storage region and two-dimensional (2D) placements of magneto-motive forces were designed by tuning the magnetic field eigenmode strengths obtained by the magnetic field. The tuning was performed iteratively. Magnetic field ripples in the azimuthal direction were minimized for the design. The candidate magnetic design had five CBs and an iron yoke with center iron poles. The magnet satisfied specifications of homogeneity (0.2 ppm peak-to-peak in 2D placements (the cylindrical coordinate of the radial position R and axial position Z) and less than 1.0 ppm ripples in the ring muon storage volume (0.318 m < R < 0 . 348 m and -0.05 < Z < 0.05 m) with 3.0 T strength and a slightly negative BR (magnetic field radial component) at Z > 0.0 m) for the spiral muon injection from the iron yoke at top.

Self-tuning pressure-feedback control by pole placement for vibration reduction of excavator with independent metering fluid power system

NASA Astrophysics Data System (ADS)

Ding, Ruqi; Xu, Bing; Zhang, Junhui; Cheng, Min

2017-08-01

Independent metering control systems are promising fluid power technologies compared with traditional valve controlled systems. By breaking the mechanical coupling between the inlet and outlet, the meter-out valve can open as large as possible to reduce energy consumptions. However, the lack of damping in outlet causes stronger vibrations. To address the problem, the paper designs a hybrid control method combining dynamic pressure-feedback and active damping control. The innovation resides in the optimization of damping by introducing pressure feedback to make trade-offs between high stability and fast response. To achieve this goal, the dynamic response pertaining to the control parameters consisting of feedback gain and cut-off frequency, are analyzed via pole-zero locations. Accordingly, these parameters are tuned online in terms of guaranteed dominant pole placement such that the optimal damping can be accurately captured under a considerable variation of operating conditions. The experiment is deployed in a mini-excavator. The results pertaining to different control parameters confirm the theoretical expectations via pole-zero locations. By using proposed self-tuning controller, the vibrations are almost eliminated after only one overshoot for different operation conditions. The overshoots are also reduced with less decrease of the response time. In addition, the energy-saving capability of independent metering system is still not affected by the improvement of controllability.

Pancreas Transplantation From Very Small Pediatric Donor Using the "Cephalic Placement" Technique: A Case Report.

PubMed

Chiari, D; Bissolati, M; Gazzetta, P G; Guarneri, G; Tomanin, D; Maffi, P; Secchi, A; Rosati, R; Socci, C

2016-03-01

The gap between the number of diabetic patients on the waiting list for transplantation and the number of pancreas donors is growing and it is mandatory to extend criteria for donor eligibility. Several reports showed the feasibility of pancreas transplantation from pediatric donors with comparable outcomes to adult donors in terms of long-term β-cell function. However, there is no consensus about donor age and weight limits. We present two cases of pancreas transplantation alone (PTA) from very small pediatric donors: a 2-year-old female (weight 13 kg, height 88 cm) and a 6-year-old male (weight 29 kg, height 122 cm). We used a novel "cephalic placement" technique. The pancreas was placed upon the aortic carrefour with cephalic pole upward with 3 anchorage points: the left common iliac vein (or the inferior cava vein), the right common iliac artery, and an ileal loop. No postoperative thrombosis occurred and the patients gained insulin independence instantaneously. CT scan performed on postoperative day 3 showed regular organ perfusion in both cases. Graft volume and surface calculated by CT reconstruction were, respectively, 25 cc and 89 cm(2) in the first case, and 46.5 cc and 123 cm(2) in the second case. Postoperative mixed meal tolerance tests showed normal glycemic profile. Patients are actually insulin independent at 4 years and 8 months. Pancreases from very young pediatric donors are adequate to restore insulin independence after PTA in adult patients. The "cephalic placement" technique is feasible and effective using very small pancreases. Copyright © 2016 Elsevier Inc. All rights reserved.

Intergration of system identification and robust controller designs for flexible structures in space

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan; Lew, Jiann-Shiun

1990-01-01

An approach is developed using experimental data to identify a reduced-order model and its model error for a robust controller design. There are three steps involved in the approach. First, an approximately balanced model is identified using the Eigensystem Realization Algorithm, which is an identification algorithm. Second, the model error is calculated and described in frequency domain in terms of the H(infinity) norm. Third, a pole placement technique in combination with a H(infinity) control method is applied to design a controller for the considered system. A set experimental data from an existing setup, namely the Mini-Mast system, is used to illustrate and verify the approach.

Automated Pole Placement Algorithm for Multivariable Optimal Control Synthesis.

DTIC Science & Technology

1985-09-01

set of Q and F The effective Qe and F, after n reassignments are given by .Q, Q Q. .. (eqn 4.11) and Fe =F, + Fa+... Fn (eqn 4.12) The above pole...Inverse transformation and determination of Q, and Fe are identical to the distinct eigenvalue case with M in equation 4.9 replaced by T. 3. System...and F and the augmented plant matrix become, Q -2.998 -149. 0.9994 -49.978 -149.9 7499 -0.00841 0.4211 The effective Q. and Fe required to move both

Upper pole access is safe and effective for pediatric percutaneous nephrolithotomy.

PubMed

Oner, Sedat; Karagozlu Akgul, Ahsen; Demirbas, Murat; Onen, Efe; Aydos, Murat; Erdogan, Abdullah

2018-04-01

Upper pole access in percutaneous nephrolithotomy (PCNL) provides a straight tract to the ureter, resulting in easier placement of a guidewire to the ureter, good exposure of the pelvis, calices, and upper ureter, and comfortable manipulations. However, despite these benefits, upper pole access is usually avoided because of the risk of chest complications in both pediatric and adult patients. We aimed to evaluate the safety and morbidity of single upper pole access in pediatric patients undergoing PCNL. We retrospectively reviewed patients aged ≤17 years with renal stones who underwent PCNL with a single access between August 2004 and February 2016. The patients were separated into two groups: the single upper pole access group (SUPAG) and the single other pole access group (SOPAG). We compared the SUPAG and SOPAG in terms of the demographic features of the patients, stone burden and location, operative data, and postoperative outcomes. Complications were classified according to the modified Clavien system. During the study period, 101 PCNL procedures were performed, 77 of which were managed with only one access. The median age of the 77 patients managed with a single access was 12 years (range 3-17 years). The number of cases in the SUPAG and SOPAG was 10 and 67, respectively. There were no statistically significant differences between the SUPAG and SOPAG in terms of age, sex, stone location, hydronephrosis status, stone area, side of kidney, and previous stone treatment or renal surgery. Furthermoret, there were no significant differences between the groups in terms of the operative parameters. Although the difference was insignificant, the median operation times in the SUPAG and SOPAG were 37 and 45 min, respectively. There was no chest complication or bleeding that required transfusion in the SUPAG. Two cases required transfusion, and one case was managed with a double pigtail catheter (double-J) placement because of prolonged extravasation in the SOPAG. The stone-free ratios were 100% and 82.1% in the SUPAG and SOPAG, respectively. Upper pole access provides similar outcomes to other (middle and lower) pole accesses, and may be performed without serious complications. These results indicate that this is a safe and effective approach of PCNL, and it presents a good alternative for removal of renal stones in pediatric patients. Copyright © 2018 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Superconductor magnetic reading and writing heads

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

Barnes, F.S.; Dugas, M.P.

1990-11-20

This paper describes a head for interfacing with a magnetic recording media. It comprises: a member of magnetic material forming at least a portion of a magnetic flux circuit ending with a pole face surface in interfacing relation to the media for establishing a main pole in proximity to the media in the magnetic flux circuit, magnetically responsive means in magnetically coupled relation to the magnetic flux circuit, means encasing at least a portion of the external surfaces of the member with superconductive material except for the media interfacing portion of the pole face surface. The encasing means including superconductingmore » material substantially surrounding the magnetic flux circuit in proximity to the pole face surface, and means establishing an environment for the superconductive material at a temperature for maintaining the superconductive material in its superconductive state, whereby magnetic flux in the magnetic flux circuit associated with the encasing means is concentrated within the magnetic flux circuit while placement of the pole face surface in proximity to the recording media permits sensitive magnetic flux controlled information exchanges between the media and the head.« less

Linear quadratic regulators with eigenvalue placement in a horizontal strip

NASA Technical Reports Server (NTRS)

Shieh, Leang S.; Dib, Hani M.; Ganesan, Sekar

1987-01-01

A method for optimally shifting the imaginary parts of the open-loop poles of a multivariable control system to the desirable closed-loop locations is presented. The optimal solution with respect to a quadratic performance index is obtained by solving a linear matrix Liapunov equation.

Fractional order implementation of Integral Resonant Control - A nanopositioning application.

PubMed

San-Millan, Andres; Feliu-Batlle, Vicente; Aphale, Sumeet S

2017-10-04

By exploiting the co-located sensor-actuator arrangement in typical flexure-based piezoelectric stack actuated nanopositioners, the polezero interlacing exhibited by their axial frequency response can be transformed to a zero-pole interlacing by adding a constant feed-through term. The Integral Resonant Control (IRC) utilizes this unique property to add substantial damping to the dominant resonant mode by the use of a simple integrator implemented in closed loop. IRC used in conjunction with an integral tracking scheme, effectively reduces positioning errors introduced by modelling inaccuracies or parameter uncertainties. Over the past few years, successful application of the IRC control technique to nanopositioning systems has demonstrated performance robustness, easy tunability and versatility. The main drawback has been the relatively small positioning bandwidth achievable. This paper proposes a fractional order implementation of the classical integral tracking scheme employed in tandem with the IRC scheme to deliver damping and tracking. The fractional order integrator introduces an additional design parameter which allows desired pole-placement, resulting in superior closed loop bandwidth. Simulations and experimental results are presented to validate the theory. A 250% improvement in the achievable positioning bandwidth is observed with proposed fractional order scheme. Copyright © 2017. Published by Elsevier Ltd.

Adaptive Identification by Systolic Arrays.

DTIC Science & Technology

1987-12-01

BIBLIOGRIAPHY Anton , Howard, Elementary Linear Algebra , John Wiley & Sons, 19S4. Cristi, Roberto, A Parallel Structure Jor Adaptive Pole Placement...10 11. SYSTEM IDENTIFICATION M*YETHODS ....................... 12 A. LINEAR SYSTEM MODELING ......................... 12 B. SOLUTION OF SYSTEMS OF... LINEAR EQUATIONS ......... 13 C. QR DECOMPOSITION ................................ 14 D. RECURSIVE LEAST SQUARES ......................... 16 E. BLOCK

Development of a two-dimensional skin friction balance nulling circuit using multivariable control theory

NASA Technical Reports Server (NTRS)

Tripp, John S.; Patek, Stephen D.

1988-01-01

Measurement of planar skin friction forces in aerodynamic testing currently requires installation of two perpendicularly mounted, single-axis balances; consequently, force components must be sensed at two distinct locations. A two-axis instrument developed at the Langley Research Center to overcome this disadvantage allows measurement of a two-dimensional force at one location. This paper describes a feedback-controlled nulling circuit developed for the NASA two-axis balance which, without external compensation, is inherently unstable because of its low friction mechanical design. Linear multivariable control theory is applied to an experimentally validated mathematical model of the balance to synthesize a state-variable feedback control law. Pole placement techniques and computer simulation studies are employed to select eigenvalues which provide ideal transient response with decoupled sensing dynamics.

Temporal parameter change of human postural control ability during upright swing using recursive least square method

NASA Astrophysics Data System (ADS)

Goto, Akifumi; Ishida, Mizuri; Sagawa, Koichi

2010-01-01

The purpose of this study is to derive quantitative assessment indicators of the human postural control ability. An inverted pendulum is applied to standing human body and is controlled by ankle joint torque according to PD control method in sagittal plane. Torque control parameters (KP: proportional gain, KD: derivative gain) and pole placements of postural control system are estimated with time from inclination angle variation using fixed trace method as recursive least square method. Eight young healthy volunteers are participated in the experiment, in which volunteers are asked to incline forward as far as and as fast as possible 10 times over 10 [s] stationary intervals with their neck joint, hip joint and knee joint fixed, and then return to initial upright posture. The inclination angle is measured by an optical motion capture system. Three conditions are introduced to simulate unstable standing posture; 1) eyes-opened posture for healthy condition, 2) eyes-closed posture for visual impaired and 3) one-legged posture for lower-extremity muscle weakness. The estimated parameters Kp, KD and pole placements are applied to multiple comparison test among all stability conditions. The test results indicate that Kp, KD and real pole reflect effect of lower-extremity muscle weakness and KD also represents effect of visual impairment. It is suggested that the proposed method is valid for quantitative assessment of standing postural control ability.

Biomechanical characteristics and speed adaptation during kick double poling on roller skis in elite cross-country skiers.

PubMed

Göpfert, Caroline; Holmberg, Hans-Christer; Stöggl, Thomas; Müller, Erich; Lindinger, Stefan Josef

2013-06-01

Recent developments in cross-country ski racing should promote the use of kick double poling. This technique, however, has not been the focus in athletes' training and has barely been investigated. The aims of the present study were to develop a function-based phase definition and to analyse speed adaptation mechanisms for kick double poling in elite cross-country skiers. Joint kinematics and pole/plantar forces were recorded in 10 athletes while performing kick double poling at three submaximal roller skiing speeds. A speed increase was associated with increases in cycle length and rate, while absolute poling and leg push-off durations shortened. Despite maintained impulses of force, the peak and average pole/leg forces increased. During double poling and leg push-off, ranges of motion of elbow flexion and extension increased (p < 0.05) and were maintained for hip/knee flexion and extension. Cycle length increase was correlated to increases in average poling force (r = 0.71) and arm swing time (r = 0.88; both p < 0.05). The main speed adaptation was achieved by changes in double poling technique; however, leg push-off showed high variability among elite skiers, thus illustrating important aspects for technique training.

Muscular and metabolic responses to different Nordic walking techniques, when style matters.

PubMed

Pellegrini, Barbara; Boccia, Gennaro; Zoppirolli, Chiara; Rosa, Raffaela; Stella, Federico; Bortolan, Lorenzo; Rainoldi, Alberto; Schena, Federico

2018-01-01

Due to poling action and upper body engagement, Nordic walking (NW) has additional health benefits with respect to conventional walking. The aim of this study was to evaluate the differences in muscle activation and metabolic responses between NW, performed with the technique suggested by NW instructors, and with some modifications in the way to move upper limb and poles. Ten NW instructors volunteered to walk on a treadmill at 5.5 km•h-1 in five conditions: walking (W), Nordic walking (NW), NW with a weak poling action (NWweak), with straight-upper limbs moving the shoulders (NWshoulder) and with elbow flexion-extension pattern and shoulder freezed (NWelbow). Poling forces, body segments and poles movement, upper and lower body muscle activation, as well as metabolic parameters were measured.All modified NW techniques elicited lower muscular activation and metabolic responses with respect to the suggested NW technique (P < 0.05). All NW techniques elicited higher muscular activation and metabolic responses than W. All parameters observed with the NWweak were lower than NW. A decreased activation of shoulder extensor muscles and increased activation of anterior deltoid muscle were the main features of NWshoulder. Lower triceps brachii muscle activation and reduced propulsive poling action with respect to NW were seen for NWelbow, resulting also in shorter steps.Nordic walking instructors, sport technicians and practitioners should be aware that any deviation from the technique usually suggested might lead to lower benefits. However it is worth to note that any walking technique with poles elicits higher metabolic responses and muscular activation than walking.

Self Assembly and Pyroelectric Poling for Organics

DTIC Science & Technology

2015-07-06

ozone or nitrogen oxides) and energetic species from corona discharge . These problems can strongly inhibit the efficient poling and large-scale...poling techniques. Although contact and corona poling protocols are quite well established for decades, there do exist some challenging problems. In...contact poling, severe charge injection from metal electrodes often results in large current that causes dielectric breakdown of films. Corona poling

Modal sensing and control of paraboloidal shell structronic system

NASA Astrophysics Data System (ADS)

Yue, Honghao; Lu, Yifan; Deng, Zongquan; Tzou, Hornsen

2018-02-01

Paraboloidal shells of revolution are commonly used as important components in the field of advanced aerospace structures and aviation mechanical systems. This study is to investigate the modal sensing behavior and the modal vibration control effect of distributed PVDF patches laminated on the paraboloidal shell. A paraboloidal shell sensing and control testing platform is set up first. Frequencies of lower order modes of the shell are obtained with the PVDF sensor and compared with the previous testing results to prove its accuracy. Then sensor patches are laminated on different positions (or different sides) of the shell and tested to reveal the relation between the sensing behaviors and their locations. Finally, a mathematical model of the structronic system is built by parameter identifications and the transfer function is derived. Independent and coupled modal controllers are designed based on the pole placement method and modal vibration control experiments are performed. The amplitude suppression ratio of each mode controlled by the pole placement controller is calculated and compared with the results obtained by using a PPF controller. Advantages of both methods are concluded and suggestions are given on how to choose control algorithm for different purpose.

Standard Transistor Array (STAR). Volume 1: Placement technique

NASA Technical Reports Server (NTRS)

Cox, G. W.; Caroll, B. D.

1979-01-01

A large scale integration (LSI) technology, the standard transistor array uses a prefabricated understructure of transistors and a comprehensive library of digital logic cells to allow efficient fabrication of semicustom digital LSI circuits. The cell placement technique for this technology involves formation of a one dimensional cell layout and "folding" of the one dimensional placement onto the chip. It was found that, by use of various folding methods, high quality chip layouts can be achieved. Methods developed to measure of the "goodness" of the generated placements include efficient means for estimating channel usage requirements and for via counting. The placement and rating techniques were incorporated into a placement program (CAPSTAR). By means of repetitive use of the folding methods and simple placement improvement strategies, this program provides near optimum placements in a reasonable amount of time. The program was tested on several typical LSI circuits to provide performance comparisons both with respect to input parameters and with respect to the performance of other placement techniques. The results of this testing indicate that near optimum placements can be achieved by use of the procedures incurring severe time penalties.

Design, parametrization, and pole placement of stabilizing output feedback compensators via injective cogenerator quotient signal modules.

PubMed

Blumthaler, Ingrid; Oberst, Ulrich

2012-03-01

Control design belongs to the most important and difficult tasks of control engineering and has therefore been treated by many prominent researchers and in many textbooks, the systems being generally described by their transfer matrices or by Rosenbrock equations and more recently also as behaviors. Our approach to controller design uses, in addition to the ideas of our predecessors on coprime factorizations of transfer matrices and on the parametrization of stabilizing compensators, a new mathematical technique which enables simpler design and also new theorems in spite of the many outstanding results of the literature: (1) We use an injective cogenerator signal module ℱ over the polynomial algebra [Formula: see text] (F an infinite field), a saturated multiplicatively closed set T of stable polynomials and its quotient ring [Formula: see text] of stable rational functions. This enables the simultaneous treatment of continuous and discrete systems and of all notions of stability, called T-stability. We investigate stabilizing control design by output feedback of input/output (IO) behaviors and study the full feedback IO behavior, especially its autonomous part and not only its transfer matrix. (2) The new technique is characterized by the permanent application of the injective cogenerator quotient signal module [Formula: see text] and of quotient behaviors [Formula: see text] of [Formula: see text]-behaviors B. (3) For the control tasks of tracking, disturbance rejection, model matching, and decoupling and not necessarily proper plants we derive necessary and sufficient conditions for the existence of proper stabilizing compensators with proper and stable closed loop behaviors, parametrize all such compensators as IO behaviors and not only their transfer matrices and give new algorithms for their construction. Moreover we solve the problem of pole placement or spectral assignability for the complete feedback behavior. The properness of the full feedback behavior ensures the absence of impulsive solutions in the continuous case, and that of the compensator enables its realization by Kalman state space equations or elementary building blocks. We note that every behavior admits an IO decomposition with proper transfer matrix, but that most of these decompositions do not have this property, and therefore we do not assume the properness of the plant. (4) The new technique can also be applied to more general control interconnections according to Willems, in particular to two-parameter feedback compensators and to the recent tracking framework of Fiaz/Takaba/Trentelman. In contrast to these authors, however, we pay special attention to the properness of all constructed transfer matrices which requires more subtle algorithms.

Design for Natural Breast Augmentation: The ICE Principle.

PubMed

Mallucci, Patrick; Branford, Olivier Alexandre

2016-06-01

The authors' published studies have helped define breast beauty in outlining key parameters that contribute to breast attractiveness. The "ICE" principle puts design into practice. It is a simplified formula for inframammary fold incision planning as part of the process for determining implant selection and placement to reproduce the 45:55 ratio previously described as fundamental to natural breast appearance. The formula is as follows: implant dimensions (I) - capacity of the breast (C) = excess tissue required (E). The aim of this study was to test the accuracy of the ICE principle for producing consistent natural beautiful results in breast augmentation. A prospective analysis of 50 consecutive women undergoing primary breast augmentation by means of an inframammary fold incision with anatomical or round implants was performed. The ICE principle was applied to all cases to determine implant selection, placement, and incision position. Changes in parameters between preoperative and postoperative digital clinical photographs were analyzed. The mean upper pole-to-lower pole ratio changed from 52:48 preoperatively to 45:55 postoperatively (p < 0.0001). Mean nipple angulation was also statistically significantly elevated from 11 degrees to 19 degrees skyward (p ≤ 0.0005). Accuracy of incision placement in the fold was 99.7 percent on the right and 99.6 percent on the left, with a standard error of only 0.2 percent. There was a reduction in variability for all key parameters. The authors have shown using the simple ICE principle for surgical planning in breast augmentation that attractive natural breasts may be achieved consistently and with precision. Therapeutic, IV.

Why are mini-implants lost: the value of the implantation technique!

PubMed

Romano, Fabio Lourenço; Consolaro, Alberto

2015-01-01

The use of mini-implants have made a major contribution to orthodontic treatment. Demand has aroused scientific curiosity about implant placement procedures and techniques. However, the reasons for instability have not yet been made totally clear. The aim of this article is to establish a relationship between implant placement technique and mini-implant success rates by means of examining the following hypotheses: 1) Sites of poor alveolar bone and little space between roots lead to inadequate implant placement; 2) Different sites require mini-implants of different sizes! Implant size should respect alveolar bone diameter; 3) Properly determining mini-implant placement site provides ease for implant placement and contributes to stability; 4) The more precise the lancing procedures, the better the implant placement technique; 5) Self-drilling does not mean higher pressures; 6) Knowing where implant placement should end decreases the risk of complications and mini-implant loss.

Highly efficient periodically poled KTP-isomorphs with large apertures and extreme domain aspect-ratios

NASA Astrophysics Data System (ADS)

Canalias, Carlota; Zukauskas, Andrius; Tjörnhamman, Staffan; Viotti, Anne-Lise; Pasiskevicius, Valdas; Laurell, Fredrik

2018-02-01

Since the early 1990's, a substantial effort has been devoted to the development of quasi-phased-matched (QPM) nonlinear devices, not only in ferroelectric oxides like LiNbO3, LiTaO3 and KTiOPO4 (KTP), but also in semiconductors as GaAs, and GaP. The technology to implement QPM structures in ferroelectric oxides has by now matured enough to satisfy the most basic frequency-conversion schemes without substantial modification of the poling procedures. Here, we present a qualitative leap in periodic poling techniques that allows us to demonstrate devices and frequency conversion schemes that were deemed unfeasible just a few years ago. Thanks to our short-pulse poling and coercive-field engineering techniques, we are able to demonstrate large aperture (5 mm) periodically poled Rb-doped KTP devices with a highly-uniform conversion efficiency over the whole aperture. These devices allow parametric conversion with energies larger than 60 mJ. Moreover, by employing our coercive-field engineering technique we fabricate highlyefficient sub-µm periodically poled devices, with periodicities as short as 500 nm, uniform over 1 mm-thick crystals, which allow us to realize mirrorless optical parametric oscillators with counter-propagating signal and idler waves. These novel devices present unique spectral and tuning properties, superior to those of conventional OPOs. Furthermore, our techniques are compatible with KTA, a KTP isomorph with extended transparency in the mid-IR range. We demonstrate that our highly-efficient PPKTA is superior both for mid-IR and for green light generation - as a result of improved transmission properties in the visible range. Our KTP-isomorph poling techniques leading to highly-efficient QPM devices will be presented. Their optical performance and attractive damage thresholds will be discussed.

Calligraphic Poling of Ferroelectric Material

NASA Technical Reports Server (NTRS)

Mohageg, Makan; Strekalov, Dmitry; Savchenkov, Anatoliy; Matsko, Adrey; Maleki, Lute; Iltchenko, Vladimir

2007-01-01

Calligraphic poling is a technique for generating an arbitrary, possibly complex pattern of localized reversal in the direction of permanent polarization in a wafer of LiNbO3 or other ferroelectric material. The technique is so named because it involves a writing process in which a sharp electrode tip is moved across a surface of the wafer to expose the wafer to a polarizing electric field in the desired pattern. The technique is implemented by use of an apparatus, denoted a calligraphic poling machine (CPM), that includes the electrode and other components as described in more detail below.

Chromophore Poling in Thin Films of Organic Glasses. 2. Two-Electrode Corona Discharge Setup

NASA Astrophysics Data System (ADS)

Vilitis, O.; Muzikante, I.; Rutkis, M.; Vembris, A.

2012-01-01

In Part 1 of the article we provided description of the corona discharge physics and overview of the methods used for corona poling in thin organic films. Subsequent sections describe comparatively simple technical methods for poling the organic nonlinear optical polymers using a two-electrode (point-to-plate or wire-to-plate) technique. The polarization build-up was studied by the DC positive corona method for poling the nonlinear optical (NLO) polymers. The experimental setup provides the corona discharge current from 0.5 μA up to 3 μA by applying 3 kV - 12 kV voltage to the corona electrode and makes possible selection among the types of corona electrodes (needle, multi-needle, wire, etc.). The results of experimental testing of the poling setup show that at fixed optimal operational parameters of poling - the sample orientation temperature and the discharge current - the corona charging of polymeric materials can successfully be performed applying the two-electrode technique. To study the dynamics of both poling and charge transport processes the three-electrode charging system - a corona triode - should be applied.

Cogging Torque Reduction Techniques for Spoke-type IPMSM

NASA Astrophysics Data System (ADS)

Bahrim, F. S.; Sulaiman, E.; Kumar, R.; Jusoh, L. I.

2017-08-01

A spoke-type interior permanent magnet synchronous motor (IPMSM) is extending its tentacles in industrial arena due to good flux-weakening capability and high power density. In many of the application, high strength of permanent magnet causes the undesirable effects of high cogging torque that can aggravate performance of the motor. High cogging torque is significantly produced by IPMSM due to the similar length and the effectiveness of the magnetic air-gap. The address of this study is to analyze and compare the cogging torque effect and performance of four common techniques for cogging torque reduction such as skewing, notching, pole pairing and rotor pole pairing. With the aid of 3-D finite element analysis (FEA) by JMAG software, a 6S-4P Spoke-type IPMSM with various rotor-PM configurations has been designed. As a result, the cogging torque effect reduced up to 69.5% for skewing technique, followed by 31.96%, 29.6%, and 17.53% by pole pairing, axial pole pairing and notching techniques respectively.

Effect of Materials and Manufacturing on the Bending Stiffness of Vaulting Poles

ERIC Educational Resources Information Center

Davis, C. L.; Kukureka, S. N.

2012-01-01

The increase in the world record height achieved in pole vaulting can be related to the improved ability of the athletes, in terms of their fitness and technique, and to the change in materials used to construct the pole. For example in 1960 there was a change in vaulting pole construction from bamboo to glass fibre reinforced polymer (GFRP)…

Experimental verification of a GPC-LPV method with RLS and P1-TS fuzzy-based estimation for limiting the transient and residual vibration of a crane system

NASA Astrophysics Data System (ADS)

Smoczek, Jaroslaw

2015-10-01

The paper deals with the problem of reducing the residual vibration and limiting the transient oscillations of a flexible and underactuated system with respect to the variation of operating conditions. The comparative study of generalized predictive control (GPC) and fuzzy scheduling scheme developed based on the P1-TS fuzzy theory, local pole placement method and interval analysis of closed-loop system polynomial coefficients is addressed to the problem of flexible crane control. The two alternatives of a GPC-based method are proposed that enable to realize this technique either with or without a sensor of payload deflection. The first control technique is based on the recursive least squares (RLS) method applied to on-line estimate the parameters of a linear parameter varying (LPV) model of a crane dynamic system. The second GPC-based approach is based on a payload deflection feedback estimated using a pendulum model with the parameters interpolated using the P1-TS fuzzy system. Feasibility and applicability of the developed methods were confirmed through experimental verification performed on a laboratory scaled overhead crane.

Control of speed during the double poling technique performed by elite cross-country skiers.

PubMed

Lindinger, Stefan Josef; Stöggl, Thomas; Müller, Erich; Holmberg, Hans-Christer

2009-01-01

Double poling (DP) as a main technique in cross-country skiing has developed substantially over the last 15 yr. The purpose of the present study was to analyze the question, "How do modern elite skiers control DP speed?" Twelve male elite cross-country skiers roller skied using DP at 9, 15, 21, and 27 km.h(-1) and maximum velocity (V(max)). Cycle characteristics, pole and plantar forces, and elbow, hip, and knee joint angles were analyzed. Both poling frequency and cycle length increased up to 27 km.h (-1)(P < 0.05), with a further increase in poling frequency at V(max) (P < 0.05). Peak pole force, rate of force development, and rearfoot plantar force increased with submaximal velocities (V(sm)), whereas poling time and time-to-peak pole force gradually shortened (P < 0.05). Changes in elbow joint kinematics during the poling phase were characterized by a decreased angle minimum and an increased flexion and extension ranges of motion as well as angular velocities across V(sm) (P < 0.05), with no further changes at V(max). Hip and knee joint kinematics adapted across V(sm) by 1) decreasing angles at pole plant and angle minima during the poling phase, 2) increasing the ranges of motion and angular velocities during the flexion phases occurring around pole plant, and 3) increasing extension ranges of motion and angular velocities during the recovery phase (all P values <0.05), with no further changes at V(max). Elite skiers control DP speed by increasing both poling frequency and cycle length; the latter is achieved by increased pole force despite reduced poling time. Adaptation to higher speeds was assisted by an increased range of motion, smaller angle minima, and higher angular velocities in the elbow, the hip, and the knee joints.

Inverse full state hybrid projective synchronization for chaotic maps with different dimensions

NASA Astrophysics Data System (ADS)

Ouannas, Adel; Grassi, Giuseppe

2016-09-01

A new synchronization scheme for chaotic (hyperchaotic) maps with different dimensions is presented. Specifically, given a drive system map with dimension n and a response system with dimension m, the proposed approach enables each drive system state to be synchronized with a linear response combination of the response system states. The method, based on the Lyapunov stability theory and the pole placement technique, presents some useful features: (i) it enables synchronization to be achieved for both cases of n < m and n > m; (ii) it is rigorous, being based on theorems; (iii) it can be readily applied to any chaotic (hyperchaotic) maps defined to date. Finally, the capability of the approach is illustrated by synchronization examples between the two-dimensional Hénon map (as the drive system) and the three-dimensional hyperchaotic Wang map (as the response system), and the three-dimensional Hénon-like map (as the drive system) and the two-dimensional Lorenz discrete-time system (as the response system).

Active vibration control of a single-stage spur gearbox

NASA Astrophysics Data System (ADS)

Dogruer, C. U.; Pirsoltan, Abbas K.

2017-02-01

The dynamic transmission error between driving and driven gears of a gear mechanism with torsional mode is induced by periodic time-varying mesh stiffness. In this study, to minimize the adverse effect of this time-varying mesh stiffness, a nonlinear controller which adjusts the torque acting on the driving gear is proposed. The basic approach is to modulate the input torque such that it compensates the periodic change in mesh stiffness. It is assumed that gears are assembled with high precision and gearbox is analyzed by a finite element software to calculate the mesh stiffness curve. Thus, change in the mesh stiffness, which is inherently nonlinear, can be predicted and canceled by a feed-forward loop. Then, remaining linear dynamics is controlled by pole placement techniques. Under these premises, it is claimed that any acceleration and velocity profile of the input shaft can be tracked accurately. Thereby, dynamic transmission error is kept to a minimum possible value and a spur gearbox, which does not emit much noise and vibration, is designed.

48. REMOVAL OF FIRST TRUSS. The first truss removed here ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

48. REMOVAL OF FIRST TRUSS. The first truss removed here rests on ground plates and awaits the similar placement of all the trusses for temporary storage. In the foreground are cut out sections of roofing also removed by crane. Note the 1873-74 standing seam sheet metal roof above the 1851 shingling. The roof pole gutters were in part made up of bench back rails. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

Output Feedback Pole-Placement in the Design of Compensators for Suboptimal Linear Quadratic Regulators.

DTIC Science & Technology

1979-06-01

also extended to the class of stabilizable systems and the required compensator shown to possess a separation property. Finally the design methodology...Page 1.1. Block diagram of transfer function given in (1.28) ........... 15 3.3.1. Compensator structure for controllable and stabilizable systems ...response will be stable. The implemented output feedback control law will stabilize the total closed loop system . n nn Let [uin and iJi= 1 be the

Reduced-order modeling for hyperthermia: an extended balanced-realization-based approach.

PubMed

Mattingly, M; Bailey, E A; Dutton, A W; Roemer, R B; Devasia, S

1998-09-01

Accurate thermal models are needed in hyperthermia cancer treatments for such tasks as actuator and sensor placement design, parameter estimation, and feedback temperature control. The complexity of the human body produces full-order models which are too large for effective execution of these tasks, making use of reduced-order models necessary. However, standard balanced-realization (SBR)-based model reduction techniques require a priori knowledge of the particular placement of actuators and sensors for model reduction. Since placement design is intractable (computationally) on the full-order models, SBR techniques must use ad hoc placements. To alleviate this problem, an extended balanced-realization (EBR)-based model-order reduction approach is presented. The new technique allows model order reduction to be performed over all possible placement designs and does not require ad hoc placement designs. It is shown that models obtained using the EBR method are more robust to intratreatment changes in the placement of the applied power field than those models obtained using the SBR method.

Effect of materials and manufacturing on the bending stiffness of vaulting poles

NASA Astrophysics Data System (ADS)

Davis, C. L.; Kukureka, S. N.

2012-09-01

The increase in the world record height achieved in pole vaulting can be related to the improved ability of the athletes, in terms of their fitness and technique, and to the change in materials used to construct the pole. For example in 1960 there was a change in vaulting pole construction from bamboo to glass fibre reinforced polymer (GFRP) composites. The lighter GFRP pole enabled the athletes to have a faster run-up, resulting in a greater take-off speed, giving them more kinetic energy to convert into potential energy and hence height. GFRP poles also have a much higher failure stress than bamboo, so the poles were engineered to bend under the load of the athlete, thereby storing elastic strain energy that can be released as the pole straightens, resulting in greater energy efficiency. The bending also allowed athletes to change their vaulting technique from a style that involved the body remaining almost upright during the vault to one where the athlete goes over the bar with their feet upwards. Modern vaulting poles can be made from GFRP and/or carbon fibre reinforced polymer (CFRP) composites. The addition of carbon fibres maintains the mechanical properties of the pole, but allows a reduction in the weight. The number and arrangement of the fibres determines the mechanical properties, in particular the bending stiffness. Vaulting poles are also designed for an individual athlete to take into account each athlete’s ability and physical characteristics. The poles are rated by ‘weight’ to allow athletes to select an appropriate pole for their ability. This paper will review the development of vaulting poles and the requirements to maximize performance. The properties (bending stiffness and pre-bend) and microstructure (fibre volume fraction and lay-up) of typical vaulting poles will be discussed. Originally published as Davis C L and Kukureka S N (2004) Effect of materials and manufacturing on the bending stiffness of vaulting poles The Engineering of Sport 5 ed M Hubbard, R D Mehta and J M Pallis (Sheffield: ISEA). Republished here with permission from ISEA.

Dual-gate GaAs FET switches

NASA Astrophysics Data System (ADS)

Vorhaus, J. L.; Fabian, W.; Ng, P. B.; Tajima, Y.

1981-02-01

A set of multi-pole, multi-throw switch devices consisting of dual-gate GaAs FET's is described. Included are single-pole, single-throw (SPST), double-pole, double-throw (DPDT), and single-pole four-throw (SP4T) switches. Device fabrication and measurement techniques are discussed. The device models for these switches were based on an equivalent circuit of a dual-gate FET. The devices were found to have substantial gain in X-band and low Ku-band.

Unraveling the nature of electric field- and stress- induced structural transformations in soft PZT by a new powder poling technique.

PubMed

Kalyani, Ajay Kumar; V, Lalitha K; James, Ajit R; Fitch, Andy; Ranjan, Rajeev

2015-02-25

A 'powder-poling' technique was developed to study electric field induced structural transformations in ferroelectrics exhibiting a morphotropic phase boundary (MPB). The technique was employed on soft PZT exhibiting a large longitudinal piezoelectric response (d(33) ∼ 650 pC N(-1)). It was found that electric poling brings about a considerable degree of irreversible tetragonal to monoclinic transformation. The same transformation was achieved after subjecting the specimen to mechanical stress, which suggests an equivalence of stress and electric field with regard to the structural mechanism in MPB compositions. The electric field induced structural transformation was also found to be accompanied by a decrease in the spatial coherence of polarization.

CT-guided thermocouple placement for hyperthermia treatment.

PubMed

Banerian, K G; Roberts, J L; Borrego, J C; Martinez, A

1990-05-01

There is a well-documented synergistic cytotoxic effect when heat is combined with ionizing radiation. An integral component of hyperthermia treatments is the placement of thermocouple probes used for thermal dosimetry. With the surge in interest in the clinical use of hyperthermia, our department is performing an increasing number of thermocouple placements under computed tomographic (CT) guidance. We describe our technique for CT-guided thermocouple placement with two different systems: a trocar introduction system and a peel-away needle introduction system. We discuss the rationale for thermocouple placement, our early experience with this technique, and some potential complications.

The History of Nontraditional or Ectopic Placement of Reservoirs in Prosthetic Urology.

PubMed

Perito, Paul; Wilson, Steven

2016-04-01

Reservoir placement during implantation of prosthetic urology devices has been problematic throughout the history of the surgical treatment of erectile dysfunction and urinary incontinence. We thought it would be interesting to review the history of reservoir placement leading up to current surgical techniques. To provide an overview of the past and present techniques for reservoir placement and discuss the evolutionary process leading to safe and effective placement of prosthetic reservoirs. We reviewed data pertaining to inflatable penile prosthesis (IPP) reservoirs and pressure-regulating balloons (PRB) in a chronological fashion, spanning 25 years. Main outcomes included a historical review of techniques for IPP reservoir and PRB placement leading to the subsequent incremental improvements in safety and efficacy when performing penile implants and artificial urinary sphincters. Prosthetic urologic reservoirs have traditionally been placed in the retropubic space. Over the years, urologists have attempted use of alternative spaces including peritoneal, epigastric, "ectopic," posterior to transversalis, and high submuscular. Current advances in prosthetic urologic reservoir placement allow safe and effective abdominal wall placement of reservoirs. These novel approaches appear to be so effective that urologists may now be able to cease using the traditional retropubic space for reservoir placement, even in the case of virgin pelves. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Rapid-scan EPR of immobilized nitroxides

NASA Astrophysics Data System (ADS)

Yu, Zhelin; Quine, Richard W.; Rinard, George A.; Tseitlin, Mark; Elajaili, Hanan; Kathirvelu, Velavan; Clouston, Laura J.; Boratyński, Przemysław J.; Rajca, Andrzej; Stein, Richard; Mchaourab, Hassane; Eaton, Sandra S.; Eaton, Gareth R.

2014-10-01

X-band electron paramagnetic resonance spectra of immobilized nitroxides were obtained by rapid scan at 293 K. Scan widths were 155 G with 13.4 kHz scan frequency for 14N-perdeuterated tempone and for T4 lysozyme doubly spin labeled with an iodoacetamide spirocyclohexyl nitroxide and 100 G with 20.9 kHz scan frequency for 15N-perdeuterated tempone. These wide scans were made possible by modifications to our rapid-scan driver, scan coils made of Litz wire, and the placement of highly conducting aluminum plates on the poles of a Bruker 10″ magnet to reduce resistive losses in the magnet pole faces. For the same data acquisition time, the signal-to-noise for the rapid-scan absorption spectra was about an order of magnitude higher than for continuous wave first-derivative spectra recorded with modulation amplitudes that do not broaden the lineshapes.

Theoretical constraints in the design of multivariable control systems

NASA Technical Reports Server (NTRS)

Rynaski, E. G.; Mook, D. J.

1993-01-01

The theoretical constraints inherent in the design of multivariable control systems were defined and investigated. These constraints are manifested by the system transmission zeros that limit or bound the areas in which closed loop poles and individual transfer function zeros may be placed. These constraints were investigated primarily in the context of system decoupling or non-interaction. It was proven that decoupling requires the placement of closed loop poles at the system transmission zeros. Therefore, the system transmission zeros must be minimum phase to guarantee a stable decoupled system. Once decoupling has been accomplished, the remaining part of the system exhibits transmission zeros at infinity, so nearly complete design freedom is possible in terms of placing both poles and zeros of individual closed loop transfer functions. A general, dynamic inversion model following system architecture was developed that encompasses both the implicit and explicit configuration. Robustness properties are developed along with other attributes of this type of system. Finally, a direct design is developed for the longitudinal-vertical degrees of freedom of aircraft motion to show how a direct lift flap can be used to improve the pitch-heave maneuvering coordination for enhanced flying qualities.

Malignant biliary obstruction complicated by ascites: Closure of the transhepatic tract with cyanoacrylate glue after placement of an endoprosthesis

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

Cekirge, Saruhan; Akhan, Okan; Ozmen, Mustafa

1997-05-15

A new technique using cyanoacrylate glue is suggested for closing the transparenchymal tract following metallic endoprosthesis placement in a patient with malignant biliary obstruction complicated by ascites. With this technique, complications related to bile reflux through the transparenchymal tract would be avoided after transhepatic endoprosthesis placement in patients who have ascites. This technique would also be useful for avoiding bleeding following transhepatic portal venous puncture.

The Derivation of Simple Poles in a Transfer Function from Real Frequency Information. Part 3. Object Classification and Identification,

DTIC Science & Technology

1977-01-10

This report is the third in a series of three that evaluate a technique (frequency-domain Prony) for obtaining the poles of a transfer function. The...main objective was to assess the feasibility of classifying or identifying ship-like targets by using pole sets derived from frequency-domain data. A...predictor-correlator procedure for using spectral data and library pole sets for this purpose was developed. Also studied was an iterative method for

Influence of kinematic parameters on pole vault results in top juniors.

PubMed

Gudelj, Ines; Zagorac, Nebojsa; Babić, Vesna

2013-05-01

The aim of this research was to analyse the kinematic parameters and to ascertain the influence of those parameters on the pole vault result. The entity sample of the research consisted of successful vaults of 30 athletes, whose attempts were recorded at the European Junior Athletics Championships. The examinees performed the vaults as part of the qualification competition for the finale and the finale of the competition itself The examinees were 17-19 years old, and the range of their top results was from 4.90 to 5.30 m. The results of the regression analysis showed a significant influence of the predictor variables on the effective pole vault height. The centre of body mass height was mostly influenced by the following variables: TS - takeoff velocity, LSS - last step velocity, PSS - penultimate step velocity, TAPR - trunk angle at the moment of the pole release. The following variables had lesser, but still a significant influence: CBMDM - centre of body mass distance at the pole release moment, and MCMVV - time of pole straightening. Generally, the information gained by this research indicates the significant influence of the kinematic parameters on the pole vault result. Therefore, the conclusion is that the result efficacy in the pole vault is primarily determined by the variables defined by the motor capabilities, but also by the indicators determining the vault activity realization technique. The variables that define the body position during the pole release (trunk angle and centre of mass distance) have heomost significant influence on the vault performance technique, while the motor capabilities influence the last two run up steps velocity, take off speed and the time of pole straightening.

Sampling tree tops by helicopter...special pole pruner cuts branchlets

Treesearch

John F. Wear; Robert G. Winterfeld

1966-01-01

A new technique for sampling tops of tall Douglas-fir trees by using a special pole pruner from a helicopter has been developed and field-tested. Thee pole pruner cuts and holds a branchlet. Foliage samples collected will be compared by spectral analysis to show the type of aerial imagery that best differentiates healthy trees from those attacked by root rot.

A singular finite element technique for calculating continuum damping of Alfvén eigenmodes

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

Bowden, G. W.; Hole, M. J.

2015-02-15

Damping due to continuum resonances can be calculated using dissipation-less ideal magnetohydrodynamics provided that the poles due to these resonances are properly treated. We describe a singular finite element technique for calculating the continuum damping of Alfvén waves. A Frobenius expansion is used to determine appropriate finite element basis functions on an inner region surrounding a pole due to the continuum resonance. The location of the pole due to the continuum resonance and mode frequency is calculated iteratively using a Galerkin method. This method is used to find the complex frequency and mode structure of a toroidicity-induced Alfvén eigenmode inmore » a large aspect ratio circular tokamak and is shown to agree closely with a complex contour technique.« less

Evolution and revolution: gauging the impact of technological and technical innovation on Olympic performance.

PubMed

Balmer, Nigel; Pleasence, Pascoe; Nevill, Alan

2012-01-01

A number of studies have pointed to a plateauing of athletic performance, with the suggestion that further improvements will need to be driven by revolutions in technology or technique. In the present study, we examine post-war men's Olympic performance in jumping events (pole vault, long jump, high jump, triple jump) to determine whether performance has indeed plateaued and to present techniques, derived from models of human growth, for assessing the impact of technological and technical innovation over time (logistic and double logistic models of growth). Significantly, two of the events involve well-documented changes in technology (pole material in pole vault) or technique (the Fosbury Flop in high jump), while the other two do not. We find that in all four cases, performance appears to have plateaued and that no further "general" improvement should be expected. In the case of high jump, the double logistic model provides a convenient method for modelling and quantifying a performance intervention (in this case the Fosbury Flop). However, some shortcomings are revealed for pole vault, where evolutionary post-war improvements and innovation (fibre glass poles) were concurrent, preventing their separate identification in the model. In all four events, it is argued that further general growth in performance will indeed need to rely predominantly on technological or technical innovation.

Three-dimensional Force and Kinematic Interactions in V1 Skating at High Speeds.

PubMed

Stöggl, Thomas; Holmberg, Hans-Christer

2015-06-01

To describe the detailed kinetics and kinematics associated with use of the V1 skating technique at high skiing speeds and to identify factors that predict performance. Fifteen elite male cross-country skiers performed an incremental roller-skiing speed test (Vpeak) on a treadmill using the V1 skating technique. Pole and plantar forces and whole-body kinematics were monitored at four submaximal speeds. The propulsive force of the "strong side" pole was greater than that of the "weak side" (P < 0.01), but no difference was observed for the legs. The poles generated approximately 44% of the total propulsion, being more effective than the legs in this respect (∼59% vs 11%, P < 0.001). Faster skiers exhibited more well-synchronized poling, exhibited more symmetric edging by and forces from the legs, and were more effective in transformation of resultant forces into propulsion. Cycle length was not correlated with either Vpeak or the impulse of total propulsive forces. The present findings provide novel insights into the coordination, kinetics, and kinematics of the arm and leg motion by elite athletes while V1 skating at high speeds. The faster skiers exhibit more symmetric leg motion on the "strong" and "weak" sides, as well as more synchronized poling. With respect to methods, the pressure insoles and three-dimensional kinematics in combination with the leg push-off model described here can easily be applied to all skating techniques, aiding in the evaluation of skiing techniques and comparison of effectiveness.

A Scapholunate Ligament-Sparing Technique Utilizing the Medial Femoral Condyle Corticocancellous Free Flap to Reconstruct Scaphoid Nonunions With Proximal Pole Avascular Necrosis.

PubMed

Kazmers, Nikolas H; Thibaudeau, Stephanie; Levin, L Scott

2016-09-01

This article demonstrates a technique for the treatment of scaphoid fracture waist and proximal pole nonunions with avascular necrosis using a free vascularized medial femoral condyle flap. We present our surgical technique and representative case examples in which the scapholunate ligament, a key structure required to preserve carpal kinematics, is spared. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Separate vertical wiring for the fixation of comminuted fractures of the inferior pole of the patella.

PubMed

Song, Hyung Keun; Yoo, Je Hyun; Byun, Young Soo; Yang, Kyu Hyun

2014-05-01

Among patients over 50 years of age, separate vertical wiring alone may be insufficient for fixation of fractures of the inferior pole of the patella. Therefore, mechanical and clinical studies were performed in patients over the age of 50 to test the strength of augmentation of separate vertical wiring with cerclage wire (i.e., combined technique). Multiple osteotomies were performed to create four-part fractures in the inferior poles of eight pairs of cadaveric patellae. One patella from each pair was fixed with the separate wiring technique, while the other patella was fixed with a combined technique. The ultimate load to failure and stiffness of the fixation were subsequently measured. In a clinical study of 21 patients (average age of 64 years), comminuted fractures of the inferior pole of the patellae were treated using the combined technique. Operative parameters were recorded from which post-operative outcomes were evaluated. For cadaveric patellae, whose mean age was 69 years, the mean ultimate loads to failure for the separate vertical wiring technique and the combined technique were 216.4±72.4 N and 324.9±50.6 N, respectively (p=0.012). The mean stiffness for the separate vertical wiring technique and the combined technique was 241.1±68.5 N/mm and 340.8±45.3 N/mm, respectively (p=0.012). In the clinical study, the mean clinical score at final follow-up was 28.1 points. Augmentation of separate vertical wiring with cerclage wire provides enough strength for protected early exercise of the knee joint and uneventful healing.

A comparison of CT-based navigation techniques for minimally invasive lumbar pedicle screw placement.

PubMed

Wood, Martin; Mannion, Richard

2011-02-01

A comparison of 2 surgical techniques. To determine the relative accuracy of minimally invasive lumbar pedicle screw placement using 2 different CT-based image-guided techniques. Three-dimensional intraoperative fluoroscopy systems have recently become available that provide the ability to use CT-quality images for navigation during image-guided minimally invasive spinal surgery. However, the cost of this equipment may negate any potential benefit in navigational accuracy. We therefore assess the accuracy of pedicle screw placement using an intraoperative 3-dimensional fluoroscope for guidance compared with a technique using preoperative CT images merged to intraoperative 2-dimensional fluoroscopy. Sixty-seven patients undergoing minimally invasive placement of lumbar pedicle screws (296 screws) using a navigated, image-guided technique were studied and the accuracy of pedicle screw placement assessed. Electromyography (EMG) monitoring of lumbar nerve roots was used in all. Group 1: 24 patients in whom a preoperative CT scan was merged with intraoperative 2-dimensional fluoroscopy images on the image-guidance system. Group 2: 43 patients using intraoperative 3-dimensional fluoroscopy images as the source for the image guidance system. The frequencies of pedicle breach and EMG warnings (indicating potentially unsafe screw placement) in each group were recorded. The rate of pedicle screw misplacement was 6.4% in group 1 vs 1.6% in group 2 (P=0.03). There were no cases of neurologic injury from suboptimal placement of screws. Additionally, the incidence of EMG warnings was significantly lower in group 2 (3.7% vs. 10% (P=0.03). The use of an intraoperative 3-dimensional fluoroscopy system with an image-guidance system results in greater accuracy of pedicle screw placement than the use of preoperative CT scans, although potentially dangerous placement of pedicle screws can be prevented by the use of EMG monitoring of lumbar nerve roots.

Influence of PZT Coating Thickness and Electrical Pole Alignment on Microresonator Properties.

PubMed

Janusas, Giedrius; Ponelyte, Sigita; Brunius, Alfredas; Guobiene, Asta; Vilkauskas, Andrius; Palevicius, Arvydas

2016-11-10

With increasing technical requirements in the design of microresonators, the development of new techniques for lightweight, simple, and inexpensive components becomes relevant. Lead zirconate titanate (PZT) is a powerful tool in the formation of these components, allowing a self-actuation or self-sensing capability. Different fabrication methods lead to the variation of the properties of the device itself. This research paper covers the fabrication of a novel PZT film and the investigations of its chemical, surface, and dynamic properties when film thickness is varied. A screen-printing technique was used for the formation of smooth films of 60 µm, 68 µm, and 25 µm thickness. A custom-made poling technique was applied to enhance the piezoelectric properties of the designed films. However, poling did not change any compositional or surface characteristics of the films; changes were only seen in the electrical ones. The results showed that a thinner poled PZT film having a chemical composition with the highest amount of copper and zirconium led to better electrical characteristics (generated voltage of 3.5 mV).

Piezoelectric and dielectric characterization of corona and contact poled PZT-epoxy-MWCNT bulk composites

NASA Astrophysics Data System (ADS)

Banerjee, S.; Cook-Chennault, K. A.; Du, W.; Sundar, U.; Halim, H.; Tang, A.

2016-11-01

Three-phase lead zirconate titanate (PZT, PbZr0.52Ti0.48O3)-epoxy-multi-walled carbon nanotube (MWCNT) bulk composites were prepared, where the volume fraction of PZT was held constant at 30%, while the volume fraction of the MWCNTs was varied from 1.0%-10%. The samples were poled using either a parallel plate contact or contactless (corona) poling technique. The piezoelectric strain coefficient (d33), dielectric constant (ɛ), and dielectric loss tangent (tan δ) of the samples were measured at 110 Hz, and compared as a function of poling technique and volume fraction of MWCNTs. The highest values for dielectric constant and piezoelectric strain coefficients were 465.82 and 18.87 pC/N for MWCNT volume fractions of 10% and 6%, respectively. These values were obtained for samples that were poled using the corona contactless method. The impedance and dielectric spectra of the composites were recorded over a frequency range of 100 Hz-20 MHz. The impedance values observed for parallel-plate contact poled samples are higher than that of corona poled composites. The fractured surface morphology and distribution of the PZT particles and MWCNTs were observed with the aid of electron dispersion spectroscopy and a scanning electron microscope. The surface morphology of the MWCNTs was observed with the aid of a field emission transmission electron microscope.

Optical Studies and Poling of DNA NLO Waveguides

NASA Astrophysics Data System (ADS)

Heckman, Emily; Grote, James

2005-04-01

Deoxyribonucleic acid (DNA), extracted from salmon sperm through an enzyme isolation process, is precipitated with a surfactant complex, cetyltrimethl-ammonium (CTMA), for application as a nonlinear optical material. Preliminary characterization studies suggest that DNA-CTMA may be suitable for use as the host material in the poled core layer of electro-optically-active waveguide devices. Poling results and techniques for poled chromophore-DNA-CTMA films will be discussed. Optical characterization studies of the DNA-CTMA films, including optical propagation losses and considerations in making DNA-CTMA an optical quality material, will be presented.

Numerical analysis of nonminimum phase zero for nonuniform link design

NASA Technical Reports Server (NTRS)

Girvin, Douglas L.; Book, Wayne J.

1991-01-01

As the demand for light-weight robots that can operate in a large workspace increases, the structural flexibility of the links becomes more of an issue in control. When the objective is to accurately position the tip while the robot is actuated at the base, the system is nonminimum phase. One important characteristic of nonminimum phase systems is system zeros in the right half of the Laplace plane. The ability to pick the location of these nonminimum phase zeros would give the designer a new freedom similar to pole placement. This research targets a single-link manipulator operating in the horizontal plane and modeled as a Euler-Bernoulli beam with pinned-free end conditions. Using transfer matrix theory, one can consider link designs that have variable cross-sections along the length of the beam. A FORTRAN program was developed to determine the location of poles and zeros given the system model. The program was used to confirm previous research on nonminimum phase systems, and develop a relationship for designing linearly tapered links. The method allows the designer to choose the location of the first pole and zero and then defines the appropriate taper to match the desired locations. With the pole and zero location fixed, the designer can independently change the link's moment of inertia about its axis of rotation by adjusting the height of the beam. These results can be applied to the inverse dynamic algorithms that are currently under development.

Numerical analysis of nonminimum phase zero for nonuniform link design

NASA Astrophysics Data System (ADS)

Girvin, Douglas L.; Book, Wayne J.

1991-11-01

As the demand for light-weight robots that can operate in a large workspace increases, the structural flexibility of the links becomes more of an issue in control. When the objective is to accurately position the tip while the robot is actuated at the base, the system is nonminimum phase. One important characteristic of nonminimum phase systems is system zeros in the right half of the Laplace plane. The ability to pick the location of these nonminimum phase zeros would give the designer a new freedom similar to pole placement. This research targets a single-link manipulator operating in the horizontal plane and modeled as a Euler-Bernoulli beam with pinned-free end conditions. Using transfer matrix theory, one can consider link designs that have variable cross-sections along the length of the beam. A FORTRAN program was developed to determine the location of poles and zeros given the system model. The program was used to confirm previous research on nonminimum phase systems, and develop a relationship for designing linearly tapered links. The method allows the designer to choose the location of the first pole and zero and then defines the appropriate taper to match the desired locations. With the pole and zero location fixed, the designer can independently change the link's moment of inertia about its axis of rotation by adjusting the height of the beam. These results can be applied to the inverse dynamic algorithms that are currently under development.

Changes in in vivo knee contact forces through gait modification.

PubMed

Kinney, Allison L; Besier, Thor F; Silder, Amy; Delp, Scott L; D'Lima, Darryl D; Fregly, Benjamin J

2013-03-01

Knee osteoarthritis (OA) commonly occurs in the medial compartment of the knee and has been linked to overloading of the medial articular cartilage. Gait modification represents a non-invasive treatment strategy for reducing medial compartment knee force. The purpose of this study was to evaluate the effectiveness of a variety of gait modifications that were expected to alter medial contact force. A single subject implanted with a force-measuring knee replacement walked using nine modified gait patterns, four of which involved different hiking pole configurations. Medial and lateral contact force at 25, 50, and 75% of stance phase, and the average value over all of stance phase (0-100%), were determined for each gait pattern. Changes in medial and lateral contact force values relative to the subject's normal gait pattern were determined by a Kruskal-Wallis test. Apart from early stance (25% of stance), medial contact force was most effectively reduced by walking with long hiking poles and wide pole placement, which significantly reduced medial and lateral contact force during stance phase by up to 34% (at 75% of stance) and 26% (at 50% of stance), respectively. Although this study is based on data from a single subject, the results provide important insight into changes in medial and lateral contact forces through gait modification. The results of this study suggest that an optimal configuration of bilateral hiking poles may significantly reduce both medial and lateral compartment knee forces in individuals with medial knee osteoarthritis. Copyright © 2012 Orthopaedic Research Society.

Patellar Shape-Memory Fixator for the Treatment of Comminuted Fractures of the Inferior Pole of the Patella

NASA Astrophysics Data System (ADS)

Liu, Xin-Wei; Shang, Hui-Juan; Xu, Shuo-Gui; Wang, Zhi-Wei; Zhang, Chun-Cai; Fu, Qing-Ge

2011-07-01

Comminuted and displaced fractures of the inferior pole of the patella are not easy to reduce and it is difficult to fix the fragments soundly enough to allow early movement of the knee. The purpose of this study is to evaluate the clinical effectiveness of the internal fixation technique with Patellar Shape-Memory Fixator (PSMF) in acute comminuted fractures of the inferior pole of the patella. We retrospectively studied 25 patients with comminuted fractures of the inferior pole of the patella who were treated with PSMF and followed up for a mean period of 26 months (14 to 60). All the fractures healed at a mean of 6 weeks (5 to 7). The mean grading at the final follow-up was 29.5 points (27 to 30) using the Bostman score, with no observable restriction of movement. No breakage of the PSMF or infection occurred. No delayed union, nonunion, and infection were seen. This technique preserved the length of the patella, reduced the comminuted fragments of the inferior pole and avoided long-term immobilization of the knee.

Double-push skating versus V2 and V1 skating on uphill terrain in cross-country skiing.

PubMed

Stöggl, Thomas; Kampel, Wolfgang; Müller, Erich; Lindinger, Stefan

2010-01-01

The aims of the study were a) to compare the double-push skating technique with the V2 and the V1 skating techniques on an uphill terrain by a kinematic and kinetic analysis, b) to provide kinetic and kinematic data of the V1 technique at maximal skiing speeds, and c) to test the hypotheses that the double-push skating technique is faster compared with the V2 and the V1 skating techniques. Six elite skiers performed maximum speed sprints over a 60-m uphill section (7 degrees -10 degrees) using the double-push, the V2, and the V1 techniques. Pole and plantar forces and cycle characteristics were analyzed. The double-push skating technique was approximately 4.3% faster (P < 0.05) compared with the V2 skating technique and equally fast compared with the V1 skating technique. The double-push and the V2 techniques demonstrated longer cycle lengths, lower cycle rates (both P < 0.05), and equal poling frequencies and pole forces compared with the V1 technique. Cycle length, peak foot force, and knee extension ranges of motion and velocities were higher in the double-push technique compared with the V2 technique (all P values <0.05). Center of pressure was located more laterally in the double-push technique compared with the other two techniques (P < 0.05). All measured skiing speeds were drastically higher compared with former studies. The higher skiing speeds of the V1 and the double-push techniques compared with the V2 technique stress the mechanical advantage of those techniques on uphill terrain. Because of larger cycle lengths, lower cycle rate, longer recovery times, and equal poling frequency, the double-push technique might be seen as more economic on steep uphills compared with the V1 technique. From a tactical point of view compared with the V1 technique, the double-push technique needs less space due to less lateral displacement, and no technique transitions are necessary when entering and leaving an uphill section.

Laparoscopic feeding jejunostomy: also a simple technique.

PubMed

Albrink, M H; Foster, J; Rosemurgy, A S; Carey, L C

1992-01-01

Placement of feeding tubes is a common procedure for general surgeons. While the advent of percutaneous endoscopic gastrostomy has changed and improved surgical practice, this technique is contraindicated in many circumstances. In some patients placement of feeding tubes in the stomach may be contraindicated due to the risks of aspiration, gastric paresis, or gastric dysmotility. We describe a technique of laparoscopic jejunostomy tube placement which is easy and effective. It is noteworthy that this method may be used in patients who have had previous abdominal operations, and it has the added advantage of a direct peritoneal view of the viscera. We suggest that qualified laparoscopic surgeons learn the technique of laparoscopic jejunostomy.

Integrated control-system design via generalized LQG (GLQG) theory

NASA Technical Reports Server (NTRS)

Bernstein, Dennis S.; Hyland, David C.; Richter, Stephen; Haddad, Wassim M.

1989-01-01

Thirty years of control systems research has produced an enormous body of theoretical results in feedback synthesis. Yet such results see relatively little practical application, and there remains an unsettling gap between classical single-loop techniques (Nyquist, Bode, root locus, pole placement) and modern multivariable approaches (LQG and H infinity theory). Large scale, complex systems, such as high performance aircraft and flexible space structures, now demand efficient, reliable design of multivariable feedback controllers which optimally tradeoff performance against modeling accuracy, bandwidth, sensor noise, actuator power, and control law complexity. A methodology is described which encompasses numerous practical design constraints within a single unified formulation. The approach, which is based upon coupled systems or modified Riccati and Lyapunov equations, encompasses time-domain linear-quadratic-Gaussian theory and frequency-domain H theory, as well as classical objectives such as gain and phase margin via the Nyquist circle criterion. In addition, this approach encompasses the optimal projection approach to reduced-order controller design. The current status of the overall theory will be reviewed including both continuous-time and discrete-time (sampled-data) formulations.

Design of set-point weighting PIλ + Dμ controller for vertical magnetic flux controller in Damavand tokamak.

PubMed

Rasouli, H; Fatehi, A

2014-12-01

In this paper, a simple method is presented for tuning weighted PI(λ) + D(μ) controller parameters based on the pole placement controller of pseudo-second-order fractional systems. One of the advantages of this controller is capability of reducing the disturbance effects and improving response to input, simultaneously. In the following sections, the performance of this controller is evaluated experimentally to control the vertical magnetic flux in Damavand tokamak. For this work, at first a fractional order model is identified using output-error technique in time domain. For various practical experiments, having desired time responses for magnetic flux in Damavand tokamak, is vital. To approach this, at first the desired closed loop reference models are obtained based on generalized characteristic ratio assignment method in fractional order systems. After that, for the identified model, a set-point weighting PI(λ) + D(μ) controller is designed and simulated. Finally, this controller is implemented on digital signal processor control system of the plant to fast/slow control of magnetic flux. The practical results show appropriate performance of this controller.

Computation of a controlled store separation from a cavity

NASA Technical Reports Server (NTRS)

Atwood, Christopher A.

1993-01-01

Coupling of the Reynolds-averaged Navier-Stokes equations, rigid-body dynamics, and a pitch attitude control law is demonstrated in two- and three-dimensions. The application problem was the separation of a canard-controlled store from an open-flow rectangular cavity bay at a freestream Mach number of 1.2. The transient flowfield was computed using a diagonal scheme in an overset mesh framework, with the resultant aerodynamic loads used as the forcing functions in the nonlinear dynamics equations. The proportional and rate gyro sensitivities were computed a priori using pole placement techniques for the linearized dynamical equations. These fixed gain values were used in the controller for the nonlinear simulation. Reasonable comparison between the full and linearized equations for a perturbed two-dimensional missile was found. Also in two-dimensions, a controlled store was found to possess improved separation characteristics over a canard-fixed store. In three-dimensions, trajectory comparisons with wind-tunnel data for the canard-fixed case will be made. In addition, it will be determined if a canard-controlled store is an effective means of improving cavity store separation characteristics.

Silicon Processors Using Organically Reconfigurable Techniques (SPORT)

DTIC Science & Technology

2014-05-19

towards producing SWPC devices. ATR measurements on these thin films reveal a 30% increase in the EO activity of the OEOM films after thermal ...poling and recover about 50% the EO activity of thermally -poled films without poling. A simple proof-of-concept device architecture was fabricated and...device in peer-reviewed literature. New organic EO host materials developed at UD for the SPORT program offer increased thermal stability and EO

Trajectory control of robot manipulators with closed-kinematic chain mechanism

NASA Technical Reports Server (NTRS)

Nguyen, Charles C.; Pooran, Farhad J.; Premack, Timothy

1987-01-01

The problem of Cartesian trajectory control of a closed-kinematic chain mechanism robot manipulator, recently built at CAIR to study the assembly of NASA hardware for the future Space Station, is considered. The study is performed by both computer simulation and experimentation for tracking of three different paths: a straight line, a sinusoid, and a circle. Linearization and pole placement methods are employed to design controller gains. Results show that the controllers are robust and there are good agreements between simulation and experimentation. The results also show excellent tracking quality and small overshoots.

Separate Vertical Wiring for the Fixation of Comminuted Fractures of the Inferior Pole of the Patella

PubMed Central

Song, Hyung Keun; Yoo, Je Hyun; Byun, Young Soo

2014-01-01

Purpose Among patients over 50 years of age, separate vertical wiring alone may be insufficient for fixation of fractures of the inferior pole of the patella. Therefore, mechanical and clinical studies were performed in patients over the age of 50 to test the strength of augmentation of separate vertical wiring with cerclage wire (i.e., combined technique). Materials and Methods Multiple osteotomies were performed to create four-part fractures in the inferior poles of eight pairs of cadaveric patellae. One patella from each pair was fixed with the separate wiring technique, while the other patella was fixed with a combined technique. The ultimate load to failure and stiffness of the fixation were subsequently measured. In a clinical study of 21 patients (average age of 64 years), comminuted fractures of the inferior pole of the patellae were treated using the combined technique. Operative parameters were recorded from which post-operative outcomes were evaluated. Results For cadaveric patellae, whose mean age was 69 years, the mean ultimate loads to failure for the separate vertical wiring technique and the combined technique were 216.4±72.4 N and 324.9±50.6 N, respectively (p=0.012). The mean stiffness for the separate vertical wiring technique and the combined technique was 241.1±68.5 N/mm and 340.8±45.3 N/mm, respectively (p=0.012). In the clinical study, the mean clinical score at final follow-up was 28.1 points. Conclusion Augmentation of separate vertical wiring with cerclage wire provides enough strength for protected early exercise of the knee joint and uneventful healing. PMID:24719149

Integrated 3D printing and corona poling process of PVDF piezoelectric films for pressure sensor application

NASA Astrophysics Data System (ADS)

Kim, Hoejin; Torres, Fernando; Wu, Yanyu; Villagran, Dino; Lin, Yirong; Tseng, Tzu-Liang(Bill

2017-08-01

This paper presents a novel process to fabricate piezoelectric films from polyvinylidene fluoride (PVDF) polymer using integrated fused deposition modeling (FDM) 3D printing and corona poling technique. Corona poling is one of many effective poling processes that has received attention to activate PVDF as a piezoelectric responsive material. The corona poling process occurs when a PVDF polymer is exposed to a high electric field created and controlled through an electrically charged needle and a grid electrode under heating environment. FDM 3D printing has seen extensive progress in fabricating thermoplastic materials and structures, including PVDF. However, post processing techniques such as poling is needed to align the dipoles in order to gain piezoelectric properties. To further simplify the piezoelectric sensors and structures fabrication process, this paper proposes an integrated 3D printing process with corona poling to fabricate piezoelectric PVDF sensors without post poling process. This proposed process, named ‘Integrated 3D Printing and Corona poling process’ (IPC), uses the 3D printer’s nozzle and heating bed as anode and cathode, respectively, to create poling electric fields in a controlled heating environment. The nozzle travels along the programmed path with fixed distance between nozzle tip and sample’s top surface. Simultaneously, the electric field between the nozzle and bottom heating pad promotes the alignment of dipole moment of PVDF molecular chains. The crystalline phase transformation and output current generated by printed samples under different electric fields in this process were characterized by a Fourier transform infrared spectroscopy and through fatigue load frame. It is demonstrated that piezoelectric PVDF films with enhanced β-phase percentage can be fabricated using the IPC process. In addition, mechanical properties of printed PVDF was investigated by tensile testing. It is expected to expand the use of additive manufacturing to fabricate piezoelectric PVDF-based devices for applications such as sensing and energy harvesting.

New Techniques in Characterization of Ferroelectric Materials

NASA Technical Reports Server (NTRS)

Sehirlioglu, Alp

2008-01-01

Two new techniques have been developed to characterize Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) based ferroelectric single crystals: (i) electro-thermal imaging, and (ii) single crystal x-ray diffraction in the transmission mode. (i) Electro-thermal imaging is a remote sensing technique that can detect the polarization direction and poling state of a whole crystal slice. This imaging technique utilizes an IR camera to determine the field induced temperature change and does not require any special or destructive sample preparation. In the resulting images it is possible to distinguish regions of 180 deg domains. This powerful technique can be used remotely during poling to determine the poling state of the crystal to avoid over-poling that can result in inferior properties and/or cracking of the crystals. Electro-thermal imaging produced the first direct observations of polarization rotation. Under bipolar field, the domains near the corners were the first to switch direction. As the field increased above the coercive field, domains at the center part of the crystals switched direction. (ii) X-ray diffraction in the transmission mode has long been used in structure determination of organic crystals and proteins; however, it is not used much to characterize inorganic systems. 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals were examined by this XRD technique for the first time, and a never-before-seen super-lattice was revealed with a doubling of the unit cell in all three directions, giving a cell volume eight times that of a traditional perovskite unit cell. The significance of the super-lattice peaks increased with poling, indicating a structural contribution to ordering. Lack of such observations by electron diffraction in the transmission electron microscope examinations suggests the presence of a bulk effect.

Eight piece quadrupole magnet, method for aligning quadrupole magent pole tips

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

Jaski, Mark S.; Liu, Jie; Donnelly, Aric T.

The invention provides an alternative to the standard 2-piece or 4-piece quadrupole. For example, an 8-piece and a 10-piece quadrupole are provided whereby the tips of each pole may be adjustable. Also provided is a method for producing a quadrupole using standard machining techniques but which results in a final tolerance accuracy of the resulting construct which is better than that obtained using standard machining techniques.

Fiberglass distribution poles: A case study

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

Miller, M.F.; Hosford, G.S.; Boozer, J.F. III

1995-01-01

This paper addresses the design considerations and manufacturing techniques along with mechanical test results of fiberglass reinforced composite (FRC) primary distribution poles. With it`s light weight, and virtually no maintenance it offers a viable alternative for use in remote and inaccessible locations. This paper also discusses a case study where seventy five FRC primary distribution poles have been installed on a distribution system in a remote area accessible only by foot and helicopter.

A novel technique for ventriculoperitoneal shunting by flat panel detector CT-guided real-time fluoroscopy

PubMed Central

Kobayashi, Shinya; Ishikawa, Tatsuya; Mutoh, Tatsushi; Hikichi, Kentaro; Suzuki, Akifumi

2012-01-01

Background: Surgical placement of a ventriculoperitoneal shunt (VPS) is the main strategy to manage hydrocephalus. However, the failure rate associated with placement of ventricular catheters remains high. Methods: A hybrid operating room, equipped with a flat-panel detector digital subtraction angiography system containing C-arm cone-beam computed tomography (CB-CT) imaging, has recently been developed and utilized to assist neurosurgical procedures. We have developed a novel technique using intraoperative fluoroscopy and a C-arm CB-CT system to facilitate accurate placement of a VPS. Results: Using this novel technique, 39 consecutive ventricular catheters were placed accurately, and no ventricular catheter failures were experienced during the follow-up period. Only two patients experienced obstruction of the VPS, both of which occurred in the extracranial portion of the shunt system. Conclusion: Surgical placement of a VPS assisted by flat panel detector CT-guided real-time fluoroscopy enabled accurate placement of ventricular catheters and was associated with a decreased need for shunt revision. PMID:23226605

Physical-level synthesis for digital lab-on-a-chip considering variation, contamination, and defect.

PubMed

Liao, Chen; Hu, Shiyan

2014-03-01

Microfluidic lab-on-a-chips have been widely utilized in biochemical analysis and human health studies due to high detection accuracy, high timing efficiency, and low cost. The increasing design complexity of lab-on-a-chips necessitates the computer-aided design (CAD) methodology in contrast to the classical manual design methodology. A key part in lab-on-a-chip CAD is physical-level synthesis. It includes the lab-on-a-chip placement and routing, where placement is to determine the physical location and the starting time of each operation and routing is to transport each droplet from the source to the destination. In the lab-on-a-chip design, variation, contamination, and defect need to be considered. This work designs a physical-level synthesis flow which simultaneously considers variation, contamination, and defect of the lab-on-a-chip design. It proposes a maze routing based, variation, contamination, and defect aware droplet routing technique, which is seamlessly integrated into an existing placement technique. The proposed technique improves the placement solution for routing and achieves the placement and routing co-optimization to handle variation, contamination, and defect. The simulation results demonstrate that our technique does not use any defective/contaminated grids, while the technique without considering contamination and defect uses 17.0% of the defective/contaminated grids on average. In addition, our routing variation aware technique significantly improves the average routing yield by 51.2% with only 3.5% increase in completion time compared to a routing variation unaware technique.

Radical robot-assisted laparoscopic nephrectomy with thrombectomy in the vena cava.

PubMed

Estébanez Zarranz, J; Belloso Loidi, J; Gutierrez García, M A; Rubio Calaveras, V; Morales Higelmo, G; Melendo Tercilla, P; Busto Leis, L; Sanz Jaka, J P

2018-04-23

Renal cell carcinoma has a natural tendency to extend through the renal vein. When the thrombus reaches the vena cava, thrombectomy and the necessary reconstruction of the vena cava are typically performed by open pathway. Robot-assisted technology provides advantages for performing this complex technique, using a minimally invasive access. We present the technique we employed in the first case performed in our department. After performing renal artery embolisation, we conducted the surgery with the Vinci S robotic system. The main steps of the surgery are as follows: detachment and Kocher manoeuvre; release of the lower renal pole; clamping and sectioning of the renal artery; endocavitary ultrasound to locate the thrombus; placement of tourniquets in the vena cava below and above the renal veins and in the left renal vein; closure of the 3 tourniquets; opening of the vena cava; resection and extraction of the thrombus; suture of the vena cava; opening of the tourniquets; complete release of the kidney; bagging and extraction of the specimen. The surgery was performed without complications. The patient required a transfusion of 2 units of packed red blood cells and was discharged with modest renal failure (creatinine level of 1.60mg/dl). Radical nephrectomy with thrombectomy in the vena cava is a technique susceptible to severe complications and has, to date, been performed in few centres. We believe that the technique is reproducible and has clear advantages for our patients. Copyright © 2018 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

Soft-Tissue Grafting Techniques Associated With Immediate Implant Placement.

PubMed

Bishara, Mark; Kurtzman, Gregori M; Khan, Waji; Choukroun, Joseph; Miron, Richard J

2018-02-01

Immediate implant placement often presents challenges in terms of predictably obtaining soft-tissue coverage over the implant site. While delayed implant placement offers the ability for soft tissues to grow and invade the extraction socket making their attachment around implants more predictable, immediate implant placement poses a significant risk of bacterial invasion towards the implant surface as a result of insignificant soft-tissue volume. Soft-tissue grafting techniques have often been proposed for use during immediate implant placement to augment soft-tissue deficiencies, including the use of either palatal connective tissue grafts (CTGs) or collagen-derived scaffolds. However, both of these approaches have significant drawbacks in that CTGs are harvested with high patient morbidity and collagen scaffolds remain avascular and acelluar posing a risk of infection/implant contamination. More recently, platelet-rich fibrin (PRF) has been proposed as an economical and biological means to speed soft-tissue wound healing. In combination with immediate implant placement, PRF offers an easily procurable low-cost regenerative modality that offers an efficient way to improve soft-tissue attachment around implants. Furthermore, the supra-physiological concentration of defense-fighting leukocytes in PRF, combined with a dense fibrin meshwork, is known to prevent early bacterial contamination of implant surfaces, and the biological concentrations of autologous growth factors in PRF is known to increase tissue regeneration. This article discusses soft-tissue grafting techniques associated with immediate implant placement, presents several cases demonstrating the use of PRF in routine immediate implant placement, and further discusses the biological and economic advantages of PRF for the management of soft-tissue grafting during immediate implant placement.

Curiosity Uses X-ray Instrument Data for Proximity Placement

NASA Image and Video Library

2013-09-23

NASA Mars rover Curiosity used a new technique, with added autonomy for the rover, in placement of the tool-bearing turret on its robotic arm. The technique is used to assess how close the instrument is to a soil or rock surface.

Lower-pole Shaping of the Breast by Means of a Double Glandular and Cutaneous Advancement Flap: The “Arrow” Flap

PubMed Central

Gioacchini, Matteo; Bottoni, Manuela; Grassetti, Luca; Scalise, Alessandro

2015-01-01

Summary: Lower-pole shaping of the breast is sometimes a difficult challenge when performing vertical mammoplasty. The problems mostly encountered are too large breast bases, persistent dog ears, which require long incision, and poor breast projection. We report a modification of the technique that we use in breast reduction so as to better shape the lower pole and to reduce revision surgery. PMID:26034653

Biomechanical and energetic determinants of technique selection in classical cross-country skiing.

PubMed

Pellegrini, Barbara; Zoppirolli, Chiara; Bortolan, Lorenzo; Holmberg, Hans-Christer; Zamparo, Paola; Schena, Federico

2013-12-01

Classical cross-country skiing can be performed using three main techniques: diagonal stride (DS), double poling (DP), and double poling with kick (DK). Similar to other forms of human and animal gait, it is currently unclear whether technique selection occurs to minimize metabolic cost or to keep some mechanical factors below a given threshold. The aim of this study was to find the determinants of technique selection. Ten male athletes roller skied on a treadmill at different slopes (from 0° to 7° at 10km/h) and speeds (from 6 to 18km/h at 2°). The technique preferred by skiers was gathered for every proposed condition. Biomechanical parameters and metabolic cost were then measured for each condition and technique. Skiers preferred DP for skiing on the flat and they transitioned to DK and then to DS with increasing slope steepness, when increasing speed all skiers preferred DP. Data suggested that selections mainly occur to remain below a threshold of poling force. Second, critically low values of leg thrust time may limit the use of leg-based techniques at high speeds. A small role has been identified for the metabolic cost of locomotion, which determined the selection of DP for flat skiing. Copyright © 2013 Elsevier B.V. All rights reserved.

Port positioning and docking for single-stage totally robotic dissection for rectal cancer surgery with the Si and Xi Da Vinci Surgical System.

PubMed

Toh, James Wei Tatt; Kim, Seon-Hahn

2017-11-04

We have previously reported our technique of single-docking totally robotic dissection for rectal cancer surgery using the Da Vinci ® Si Surgical System in 2009. However, we have since optimised our port placement for the Si system and have developed a novel configuration of port placement and docking for the Da Vinci ® Xi Surgical System. We have performed over 700 cases using this technique with the Si system and have used our Xi technique since 2016 for totally robotic dissection for rectal cancer. We have kept the configuration of port placements for both the Xi and Si system as similar as possible, with the priorities to avoid arm collisions as well as to provide a workable port configuration of two left-handed instruments and one right-handed instrument. To date, there have had no major complications or arm collisions related to this technique of docking, port positioning and instrument placement.

Relationships between body composition, body dimensions, and peak speed in cross-country sprint skiing.

PubMed

Stoggl, Thomas; Enqvist, Jonas; Muller, Erich; Holmberg, Hans-Christer

2010-01-01

In modern sprint cross-country skiing, strength and maximal speed are major determinants of performance. The aims of this study were to ascertain the anthropometric characteristics of world-class sprint skiers and to evaluate whether a specific body composition and/or body dimension characterizes a successful sprint skier. Our hypothesis was that body height and lean body mass are related to peak speed in double poling and diagonal stride. Fourteen male national and international elite skiers performed two peak speed tests in double poling and diagonal stride roller skiing on a treadmill and were analysed using dual-energy X-ray absorptiometry to determine body composition and body dimensions. Relative pole length was positively correlated with both techniques (double poling: r = 0.77, P < 0.01; diagonal stride: r = 0.60, P < 0.05) and was the only variable that was part of the multiple regression model for both double poling and diagonal stride peak speed. Body height was not correlated with any technique, whereas lean trunk mass (r = 0.75, P < 0.01), body mass index (r = 0.66, P < 0.01), total lean mass (r = 0.69, P < 0.01), and body mass (r = 0.57, P < 0.05) were positively related to double poling peak speed. Total lean mass (absolute: r = 0.58, P < 0.05; relative: r = 0.76, P < 0.001) and relative lean mass of the trunk, arms (both r = 0.72, P < 0.01), and legs (r = 0.54, P < 0.05) were positively related to diagonal stride peak speed. In conclusion, skiers should aim to achieve a body composition with a high percentage of lean mass and low fat mass. A focus on trunk mass through increased muscle mass appears to be important, especially for double poling. The use of longer poles (percent body height) seems to be advantageous for both double poling and diagonal stride peak speed, whereas body dimensions do not appear to be a predictive factor.

A Split-Mouth Design Comparison for Lateral and Crestal Sinus Lift Techniques with Dental Implants Placements: Short Communication.

PubMed

Al-Almaie, Saad; Kavarodi, Abdul Majeed; Alorf, Ali; Alzahrani, Saeed

2017-01-01

The objective of this study is to compare and evaluate the effectiveness of implant placement and patient appraisal for two sinus lift techniques using both crestal and lateral techniques for bilateral sinus left in a split-mouth design. All implants were successfully osseointegrated without any clinical complications or peri-implant radiolucency during the follow-up period of maximum 3 years. In terms of outcomes postoperative vertigo showed to be a major concern with the crestal approach, this approach is preferred over the lateral technique because of the reduced time required for the procedure and because it is less invasive. Most patients preferred the crestal approach over the lateral approach due to the delay in implant placement.

Talar anchor placement for modified Brostrom lateral ankle stabilization procedure.

PubMed

Angirasa, Arush K; Barrett, Michael J

2008-01-01

The modified Brostrom procedure has been a proven procedure with excellent utility in the treatment of lateral ankle instability within limitation. Multiple variations of the original technique have been described in the literature to date. Included in these variations are differences in anchor placement, suture technique, or both. In this research study, we propose placing a bone screw anchor into the lateral shoulder of the talus rather than the typical placement at the lateral malleolus for anatomic reconstruction of the lateral ankle ligaments.

Side-branch technique for difficult guidewire placement in coronary bifurcation lesion.

PubMed

He, Xingwei; Gao, Bo; Liu, Yujian; Li, Zhuxi; Zeng, Hesong

2016-01-01

Despite tremendous advances in technology and skills, percutaneous coronary intervention (PCI) of bifurcation lesion (BL) remains a particular challenge for the interventionalist. During bifurcation PCI, safe guidewire placement in the main branch (MB) and the side branch (SB) is the first step for successful procedure. However, in certain cases, the complex pattern of vessel anatomy and the mix of plaque distribution may make target vessel wiring highly challenging. Therefore, specific techniques are required for solving this problem. Hereby, we describe a new use of side-branch technique for difficult guidewire placement in BL. Copyright © 2015 Elsevier Inc. All rights reserved.

Modified laparoscopic placement of peritoneal dialysis catheter with intra-abdominal fixation.

PubMed

Shen, Quanquan; Jiang, Xinxin; Shen, Xiaogang; Yu, Fangyan; Tu, Qiudi; Chen, Wangfang; Ye, Qing; Behera, Tapas Ranjan; He, Qiang

2017-08-01

Peritoneal dialysis (PD) is a commonly accepted method of treating end-stage renal disease (ESRD). Various laparoscopic techniques for the placement of PD catheter have been described. In this study, we developed a novel modified laparoscopic technique for PD catheter placement and evaluated the early results. A straight Tenckhoff PD catheter was placed employing the modified technique in 39 consecutive patients with ESRD from May 2013 to April 2016. The technique is laparoscopically guided intra-abdominal fixation of the PD catheter tip at one point by using suture passer hernia forceps. Individual information including sex, age, primary disease etiology, complications, surgical duration, morbidity, mortality and catheter survival was collected and analyzed. The modified laparoscopic procedure was effectively performed in all patients with a mean operative time of 45 ± 7 min. No conversions from laparoscopy to open surgery of catheter placement occurred. There was one case showing early pericatheter leakage. There were no serious complications, such as bleeding, abdominal wall hernias, distal catheter cuff extrusion and infections of the exit site or tunnel during surgery or the postoperative duration. No mortality was observed in this group of patients. The 6-month follow-up study showed 100% catheter-related complication-free survival. Our modified laparoscopic intra-abdominal fixation technique using suture passer hernia forceps is a simple and safe method for PD catheter placement and is effective in minimizing the risk of catheter migration.

Artifact Noise Removal Techniques on Seismocardiogram Using Two Tri-Axial Accelerometers

PubMed Central

Luu, Loc; Dinh, Anh

2018-01-01

The aim of this study is on the investigation of motion noise removal techniques using two-accelerometer sensor system and various placements of the sensors on gentle movement and walking of the patients. A Wi-Fi based data acquisition system and a framework on Matlab are developed to collect and process data while the subjects are in motion. The tests include eight volunteers who have no record of heart disease. The walking and running data on the subjects are analyzed to find the minimal-noise bandwidth of the SCG signal. This bandwidth is used to design filters in the motion noise removal techniques and peak signal detection. There are two main techniques of combining signals from the two sensors to mitigate the motion artifact: analog processing and digital processing. The analog processing comprises analog circuits performing adding or subtracting functions and bandpass filter to remove artifact noises before entering the data acquisition system. The digital processing processes all the data using combinations of total acceleration and z-axis only acceleration. The two techniques are tested on three placements of accelerometer sensors including horizontal, vertical, and diagonal on gentle motion and walking. In general, the total acceleration and z-axis acceleration are the best techniques to deal with gentle motion on all sensor placements which improve average systolic signal-noise-ratio (SNR) around 2 times and average diastolic SNR around 3 times comparing to traditional methods using only one accelerometer. With walking motion, ADDER and z-axis acceleration are the best techniques on all placements of the sensors on the body which enhance about 7 times of average systolic SNR and about 11 times of average diastolic SNR comparing to only one accelerometer method. Among the sensor placements, the performance of horizontal placement of the sensors is outstanding comparing with other positions on all motions. PMID:29614821

Kernel-Based Discriminant Techniques for Educational Placement

ERIC Educational Resources Information Center

Lin, Miao-hsiang; Huang, Su-yun; Chang, Yuan-chin

2004-01-01

This article considers the problem of educational placement. Several discriminant techniques are applied to a data set from a survey project of science ability. A profile vector for each student consists of five science-educational indicators. The students are intended to be placed into three reference groups: advanced, regular, and remedial.…

Artificial Intelligence based technique for BTS placement

NASA Astrophysics Data System (ADS)

Alenoghena, C. O.; Emagbetere, J. O.; Aibinu, A. M.

2013-12-01

The increase of the base transceiver station (BTS) in most urban areas can be traced to the drive by network providers to meet demand for coverage and capacity. In traditional network planning, the final decision of BTS placement is taken by a team of radio planners, this decision is not fool proof against regulatory requirements. In this paper, an intelligent based algorithm for optimal BTS site placement has been proposed. The proposed technique takes into consideration neighbour and regulation considerations objectively while determining cell site. The application will lead to a quantitatively unbiased evaluated decision making process in BTS placement. An experimental data of a 2km by 3km territory was simulated for testing the new algorithm, results obtained show a 100% performance of the neighbour constrained algorithm in BTS placement optimization. Results on the application of GA with neighbourhood constraint indicate that the choices of location can be unbiased and optimization of facility placement for network design can be carried out.

A modern control theory based algorithm for control of the NASA/JPL 70-meter antenna axis servos

NASA Technical Reports Server (NTRS)

Hill, R. E.

1987-01-01

A digital computer-based state variable controller was designed and applied to the 70-m antenna axis servos. The general equations and structure of the algorithm and provisions for alternate position error feedback modes to accommodate intertarget slew, encoder referenced tracking, and precision tracking modes are descibed. Development of the discrete time domain control model and computation of estimator and control gain parameters based on closed loop pole placement criteria are discussed. The new algorithm was successfully implemented and tested in the 70-m antenna at Deep Space Network station 63 in Spain.

Adjustable Parameter-Based Distributed Fault Estimation Observer Design for Multiagent Systems With Directed Graphs.

PubMed

Zhang, Ke; Jiang, Bin; Shi, Peng

2017-02-01

In this paper, a novel adjustable parameter (AP)-based distributed fault estimation observer (DFEO) is proposed for multiagent systems (MASs) with the directed communication topology. First, a relative output estimation error is defined based on the communication topology of MASs. Then a DFEO with AP is constructed with the purpose of improving the accuracy of fault estimation. Based on H ∞ and H 2 with pole placement, multiconstrained design is given to calculate the gain of DFEO. Finally, simulation results are presented to illustrate the feasibility and effectiveness of the proposed DFEO design with AP.

Comparison of the efficacy and morbidity of flexible ureterorenoscopy for lower pole stones compared with other renal locations.

PubMed

Jacquemet, Baptiste; Martin, Lucille; Pastori, Julie; Bailly, Vincent; Guichard, Guillaume; Bernardini, Stéphane; Chabannes, Eric; Bittard, Hugues; Kleinclauss, François

2014-10-01

Flexible ureterorenoscopy (f-URS) for lower pole stones (LPS) compared with other renal locations can be challenging because of anatomic and technical considerations. We aimed to compare the stone-free rate (SFR) and surgical complication rate with f-URS for LPS vs other renal locations. We performed a retrospective, single-center study including 371 f-URS for renal stone retrieval performed in our institution between January 2004 and December 2010. Among the 371 procedures included in this analysis, 139 were performed for stones located in a single renal location other than the lower pole (group 1), and 232 for at least one stone located in the lower pole (group 2). We compared the efficacy (SFR) and the morbidity of f-URS between the two groups. The success of the procedure was defined as a complete SFR 6 months after f-URS. Age, sex, history of urolithiasis, body mass index, and preoperative stent placement did not differ between the two groups. No differences in stone characteristics were observed between both groups except stone size under 10 mm that was significantly higher in group 2 (P=0.018). Technical aspects of the procedure did not differ between the groups, except for more frequent use of an access sheath in group 2 (P=0.007). SFR was comparable between groups (P=0.774). The complication rate was similar in both groups, as was the severity of complications. By multivariate analysis, stone size >10 mm (P<0.0001) and multiple stone locations (P=0.001) were associated with f-URS failure, but lower pole location did not impact on SFR. In our study, stone location, in particular LPS, did not have any impact on efficacy and morbidity of f-URS. Only multiple locations and stone size >10 mm seemed to significantly decrease the SFR, without impacting morbidity.

A Split-Mouth Design Comparison for Lateral and Crestal Sinus Lift Techniques with Dental Implants Placements: Short Communication

PubMed Central

Al-Almaie, Saad; Kavarodi, Abdul Majeed; Alorf, Ali; Alzahrani, Saeed

2017-01-01

Objective: The objective of this study is to compare and evaluate the effectiveness of implant placement and patient appraisal for two sinus lift techniques using both crestal and lateral techniques for bilateral sinus left in a split-mouth design. Introduction: All implants were successfully osseointegrated without any clinical complications or peri-implant radiolucency during the follow-up period of maximum 3 years. Methods: In terms of outcomes postoperative vertigo showed to be a major concern with the crestal approach, this approach is preferred over the lateral technique because of the reduced time required for the procedure and because it is less invasive. Results: Most patients preferred the crestal approach over the lateral approach due to the delay in implant placement. PMID:29290838

A technique for open trocar placement in laparoscopic surgery using the umbilical cicatrix tube.

PubMed

Lal, Pawanindra; Sharma, R; Chander, R; Ramteke, V K

2002-09-01

Increasingly the open method for placement of the initial or first trocar is replacing the conventional technique with the Veress needle. Indeed, it is preferred because it affords peritoneal access under direct vision. A number of methods have been described in the literature using a variety of approaches and different instruments. We describe a method of open trocar placement in the supra- or subumbilical region that follows a stepwise procedure and employs specific instruments sequentially, while utilizing the umbilical cicatrix pillar or tube. This technique has been done in 525 cases with no complications or port site hernias. This is a simple technique that is safe and easy to learn. It can be performed rapidly and is a reliable method for the insertion of the first port under vision.

Sealing properties of one-step root-filling fibre post-obturators vs. two-step delayed fibre post-placement.

PubMed

Monticelli, Francesca; Osorio, Raquel; Toledano, Manuel; Ferrari, Marco; Pashley, David H; Tay, Franklin R

2010-07-01

The sealing properties of a one-step obturation post-placement technique consisting of Resilon-capped fibre post-obturators were compared with a two-step technique based on initial Resilon root filling following by 24h-delayed fibre post-placement. Thirty root segments were shaped to size 40, 0.04 taper and filled with: (1) InnoEndo obturators; (2) Resilon/24h-delayed FibreKor post-cementation. Obturator, root filling and post-cementation procedures were performed using InnoEndo bonding agent/dual-cured root canal sealer. Fluid flow rate through the filled roots was evaluated at 10psi using a computerised fluid filtration model before root resection and after 3 and 9mm apical resections. Fluid flow data were analysed using two-way repeated measures ANOVA and Tukey test to examine the effects of root-filling post-placement techniques and root resection lengths on fluid leakage from the filled canals (alpha=0.05). A significantly greater amount of fluid leakage was observed with the one-step technique when compared with two-step technique. No difference in fluid leakage was observed among intact canals and canals resected at different lengths for both materials. The seal of root canals achieved with the one-step obturator is less effective than separate Resilon root fillings followed by a 24-h delay prior to the fibre post-placement. Incomplete setting of the sealer and restricted relief of polymerisation shrinkage stresses may be responsible for the inferior seal of the one-step root-filling/post-restoration technique. Copyright 2010 Elsevier Ltd. All rights reserved.

Economic and Demographic Factors Impacting Placement of Students with Autism

ERIC Educational Resources Information Center

Kurth, Jennifer A.; Mastergeorge, Ann M.; Paschall, Katherine

2016-01-01

Educational placement of students with autism is often associated with child factors, such as IQ and communication skills. However, variability in placement patterns across states suggests that other factors are at play. This study used hierarchical cluster analysis techniques to identify demographic, economic, and educational covariates…

Detection of active decay at groundline in utility poles

Treesearch

Alex L. Shigo; Walter C. Shortle; Julian Ochrymowych

1977-01-01

Active wood decay at groundline in in-service utility poles can be detected by a skilled inspector using: 1. A knowledge of basic patterns of decay. 2. Recognition of obvious signs of decay. 3. Proper interpretation of information obtained from a pulsed-current meter-Shigometer®-used with various probes and probing techniques.

On Partial Fraction Expansion with Multiple Poles. Classroom Notes

ERIC Educational Resources Information Center

Hou, Shui-Hung; Hou, Edwin Sui-Hoi

2004-01-01

A simple and novel method for evaluating the partial fraction expansion of proper rational functions is presented. The technique involves simultaneous determination of the partial fraction coefficients associated with each of the multiple poles in the expansion in turn. Only synthetic division is required, which makes the process very suitable for…

Low Profile Mesh Plating for Patella Fractures: Video of a Novel Surgical Technique.

PubMed

Verbeek, Diederik O; Hickerson, Lindsay E; Warner, Stephen J; Helfet, David L; Lorich, Dean G

2016-08-01

Patella fractures can be challenging to treat particularly in the presence of inferior pole comminution. In this video we present a novel surgical technique for the treatment of patella fractures using a small fragment low profile mesh plate. Key points are the surgical exposure with direct visualization of the articular reduction, the preparation of the mesh plate to accommodate patellar anatomy and the augmentation of the construct using Krackow sutures to address inferior pole comminution. Low profile mesh plating allows for multiplanar fixation of patella fractures while avoiding implant and fixation problems related to tension band fixation. Our early experience with this technique is encouraging and it appears that this technique is useful for the treatment of the majority of patella fractures.

Numerical analysis of right-half plane zeros for a single-link manipulator. M.S. Thesis

NASA Technical Reports Server (NTRS)

Girvin, Douglas Lynn

1992-01-01

The purpose of this research is to further develop an understanding of how nonminimum phase zero location is affected by structural link design. As the demand for light-weight robots that can operate in a large workspace increases, the structural flexibility of the links become more of an issue in controls problems. When the objective is to accurately position the tip while the robot is actuated at the base, the system is nonminimum phase. One important characteristic of nonminimum phase systems is system zeros in the right half of the Laplace plane. The ability to pick the location of these nonminimum phase zeros would give the designer a new freedom similar to pole placement. The research targets a single-link manipulator operating in the horizontal plane and modeled as a Euler-Bernoulli beam with pinned-free end conditions. Using transfer matrix theory, one can consider link designs that have variable cross-sections along the length of the beam. A FORTRAN program was developed to determine the location of poles and zeros given the system model. The program was used to confirm previous research on nonminimum phase systems, and develop a relationship for designing linearly tapered links. The method allows the designer to choose the location of the first pole and zero and then defines the appropriate taper to match the desired locations. With the pole and zero location fixes, the designer can independently change the link's moment of inertia about its axis of rotation by adjusting the height of the beam. These results can be applied to inverse dynamic algorithms currently under development at Georgia Tech.

Bone graft in the treatment of nonunion of the scaphoid with necrosis of the proximal pole: a literature review.

PubMed

Severo, Antônio Lourenço; Lemos, Marcelo Barreto; Lech, Osvandré Luiz Canfield; Barreto Filho, Danilo; Strack, Daniel Paulo; Candido, Larissa Knapp

2017-01-01

Scaphoid fractures are the most common fractures of the carpal bones, corresponding to 60%. Of these, 10% progress to nonunion; moreover, 3% can present necrosis of the proximal pole. There are various methods of treatment using vascularized and non-vascularized bone grafts. To evaluate and compare the rate of scaphoid consolidation with necrosis of the proximal pole using different surgical techniques. The authors conducted a review of the literature using the following databases: PubMed and BIREME/LILACS, where 13 case series were selected (ten with use of vascularized bone grafts and three of non-vascularized bone grafts), according to inclusion and exclusion criteria. In most cases VBGs were used, especially those based on the 1,2 intercompartmental supraretinacular artery, due to greater reproducibility in performing the surgical technique.

A nonlinear controller design for permanent magnet motors using a synchronization-based technique inspired from the Lorenz system.

PubMed

Zaher, Ashraf A

2008-03-01

The dynamic behavior of a permanent magnet synchronous machine (PMSM) is analyzed. Nominal and special operating conditions are explored to show that the PMSM can experience chaos. A nonlinear controller is introduced to control these unwanted chaotic oscillations and to bring the PMSM to a stable steady state. The designed controller uses a pole-placement approach to force the closed-loop system to follow the performance of a simple first-order linear system with zero steady-state error to a desired set point. The similarity between the mathematical model of the PMSM and the famous chaotic Lorenz system is utilized to design a synchronization-based state observer using only the angular speed for feedback. Simulation results verify the effectiveness of the proposed controller in eliminating the chaotic oscillations while using a single feedback signal. The superiority of the proposed controller is further demonstrated by comparing it with a conventional PID controller. Finally, a laboratory-based experiment was conducted using the MCK2812 C Pro-MS(BL) motion control kit to confirm the theoretical results and to verify both the causality and versatility of the proposed controller.

Strong stabilization servo controller with optimization of performance criteria.

PubMed

Sarjaš, Andrej; Svečko, Rajko; Chowdhury, Amor

2011-07-01

Synthesis of a simple robust controller with a pole placement technique and a H(∞) metrics is the method used for control of a servo mechanism with BLDC and BDC electric motors. The method includes solving a polynomial equation on the basis of the chosen characteristic polynomial using the Manabe standard polynomial form and parametric solutions. Parametric solutions are introduced directly into the structure of the servo controller. On the basis of the chosen parametric solutions the robustness of a closed-loop system is assessed through uncertainty models and assessment of the norm ‖•‖(∞). The design procedure and the optimization are performed with a genetic algorithm differential evolution - DE. The DE optimization method determines a suboptimal solution throughout the optimization on the basis of a spectrally square polynomial and Šiljak's absolute stability test. The stability of the designed controller during the optimization is being checked with Lipatov's stability condition. Both utilized approaches: Šiljak's test and Lipatov's condition, check the robustness and stability characteristics on the basis of the polynomial's coefficients, and are very convenient for automated design of closed-loop control and for application in optimization algorithms such as DE. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Design of set-point weighting PI{sup λ} + D{sup μ} controller for vertical magnetic flux controller in Damavand tokamak

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

Rasouli, H.; Fatehi, A.

2014-12-15

In this paper, a simple method is presented for tuning weighted PI{sup λ} + D{sup μ} controller parameters based on the pole placement controller of pseudo-second-order fractional systems. One of the advantages of this controller is capability of reducing the disturbance effects and improving response to input, simultaneously. In the following sections, the performance of this controller is evaluated experimentally to control the vertical magnetic flux in Damavand tokamak. For this work, at first a fractional order model is identified using output-error technique in time domain. For various practical experiments, having desired time responses for magnetic flux in Damavand tokamak,more » is vital. To approach this, at first the desired closed loop reference models are obtained based on generalized characteristic ratio assignment method in fractional order systems. After that, for the identified model, a set-point weighting PI{sup λ} + D{sup μ} controller is designed and simulated. Finally, this controller is implemented on digital signal processor control system of the plant to fast/slow control of magnetic flux. The practical results show appropriate performance of this controller.« less

Effective Control of Computationally Simulated Wing Rock in Subsonic Flow

NASA Technical Reports Server (NTRS)

Kandil, Osama A.; Menzies, Margaret A.

1997-01-01

The unsteady compressible, full Navier-Stokes (NS) equations and the Euler equations of rigid-body dynamics are sequentially solved to simulate the delta wing rock phenomenon. The NS equations are solved time accurately, using the implicit, upwind, Roe flux-difference splitting, finite-volume scheme. The rigid-body dynamics equations are solved using a four-stage Runge-Kutta scheme. Once the wing reaches the limit-cycle response, an active control model using a mass injection system is applied from the wing surface to suppress the limit-cycle oscillation. The active control model is based on state feedback and the control law is established using pole placement techniques. The control law is based on the feedback of two states: the roll-angle and roll velocity. The primary model of the computational applications consists of a 80 deg swept, sharp edged, delta wing at 30 deg angle of attack in a freestream of Mach number 0.1 and Reynolds number of 0.4 x 10(exp 6). With a limit-cycle roll amplitude of 41.1 deg, the control model is applied, and the results show that within one and one half cycles of oscillation, the wing roll amplitude and velocity are brought to zero.

Validation of a technique for accurate fine-wire electrode placement into posterior gluteus medius using real-time ultrasound guidance.

PubMed

Hodges, P W; Kippers, V; Richardson, C A

1997-01-01

Fine-wire electromyography is primarily utilised for the recording of activity of the deep musculature, however, due to the location of these muscles, accurate electrode placement is difficult. Real-time ultrasound imaging (RTUI) of muscle tissue has been used for the guidance of the needle insertion for the placement of electrodes into the muscles of the abdominal wall. The validity of RTUI guidance of needle insertion into the deep muscles has not been determined. A cadaveric study was conducted to evaluate the accuracy with which RTUI can be used to guide fine-wire electrode placement using the posterior fibres of gluteus medius (PGM) as an example. Pilot studies revealed that the ultrasound resolution of cadaveric tissue is markedly reduced making it impossible to directly evaluate the technique, therefore, three studies were conducted. An initial study involved the demarcation of the anatomical boundaries of PGM using RTUI to define a technique based on an anatomical landmark that was consisent with the in vivo RTUI guided needle placement technique. This anatomical landmark was then used as the guide for the cadaveric needle insertion. Once the needle was positioned 0.05 ml of dye was introduced and the specimen dissected. The dye was accurately placed in PGM in 100% of the specimens. Finally, fine-wire electrodes were inserted into the PGM of five volunteers and manoeuvres performed indicating the accuracy of placement. This study supports the use of ultrasound imaging for the accurate guidance of needle insertion for fine-wire and needle EMG electrodes.

Intraoperative fluoroscopic evaluation of screw placement during pelvic and acetabular surgery.

PubMed

Yi, Chengla; Burns, Sean; Hak, David J

2014-01-01

The surgical treatment of pelvic and acetabular fractures can be technically challenging. Various techniques are available for the reconstruction of pelvic and acetabular fractures. Less invasive percutaneous fracture stabilization techniques, with closed reduction or limited open reduction, have been developed and are gaining popularity in the management of pelvic and acetabular fractures. These techniques require knowledge and interpretation of various fluoroscopic images to ensure appropriate and safe screw placement. Given the anatomic complexity of the intrapelvic structures and the 2-dimensional nature of standard fluoroscopy, multiple images oriented in different planes are needed to assess the accuracy of guide wire and screw placement. This article reviews the fluoroscopic imaging of common screw orientations during pelvic and acetabular surgery.

The physiological and biomechanical differences between double poling and G3 skating in world class cross-country skiers.

PubMed

Sandbakk, Øyvind; Leirdal, Stig; Ettema, Gertjan

2015-03-01

The current study compared differences in cycle characteristics, energy expenditure and peak speed between double poling (DP) and G3 skating. Eight world class male sprint skiers performed a 5-min submaximal test at 16 km h(-1) and an incremental test to exhaustion at a 5% incline during treadmill roller skiing with two different techniques: DP where all propulsion comes from poling, and G3 skating where leg skating is added to each double poling movement. Video analyses determined cycle characteristics; respiratory parameters and blood lactate concentration determined the physiological responses. G3 skating resulted in 16% longer cycle lengths at 16% lower cycle rates, whereas oxygen uptake was independent of technique during submaximal roller skiing. The corresponding advantages for G3 skating during maximal roller skiing were reflected in 14% higher speed, 30% longer cycle length at 16% lower cycle rate and 11% higher peak oxygen uptake (all p < 0.05). Compared to DP approximately 14% higher speed was achieved when leg push-offs were added in G3 skating. This was done by major increases in cycle lengths at slightly lower cycle rates and a higher aerobic energy delivery. However, the oxygen uptake for a given submaximal speed was not affected by technique although higher cycle rate was used in DP.

Kick, Glide, Pole! Cross-Country Skiing Fun (Part II)

ERIC Educational Resources Information Center

Duoos, Bridget A.

2012-01-01

Part I of Kick, Glide, Pole! Cross-Country Skiing Fun, which was published in last issue, discussed how to select cross-country ski equipment, dress for the activity and the biomechanics of the diagonal stride. Part II focuses on teaching the diagonal stride technique and begins with a progression of indoor activities. Incorporating this fun,…

The effects of poling on physiological, kinematic and kinetic responses in roller ski skating.

PubMed

Grasaas, Erik; Hegge, Ann Magdalen; Ettema, Gertjan; Sandbakk, Øyvind

2014-09-01

We investigated the effects of poling on physiological, kinematic and kinetic responses in the G4 skating technique where the poling movement is synchronized with the leg push-off on one side (strong side) followed by a forward arm swing during the leg push-off on the other side (weak side). G4 skating with (G4-P) and without (G4-NP) poling was compared in 17 elite male cross-country skiers during 4-min submaximal tests on a 2% inclined roller ski treadmill at 10, 15 and 20 km h(-1). G4-P demonstrated less ventilatory stress and higher gross efficiency compared to G4-NP at all velocities, and the blood lactate concentration was lower at the high velocity (all P < 0.05). Furthermore, longer cycle lengths and lower cycle rates were found with G4-P at all velocities, with correspondingly lower peak ski forces, increased ski velocities and less angling and edging of the skis (all P < 0.05). The peak ski forces on the strong side were lower than on the weak side with G4-P at all velocities (all P < 0.05), but no differences between the sides were found with G4-NP. The reduced physiological cost, higher gross efficiency and longer cycle lengths together with the lower ski forces at a given work rate with G4-P demonstrate the effectiveness of poling in the G4 skating technique. Thus, poling provides possibilities to increase total propulsion, to reduce ski forces and to enhance skiing efficiency.

Biomechanical pole and leg characteristics during uphill diagonal roller skiing.

PubMed

Lindinger, Stefan Josef; Göpfert, Caroline; Stöggl, Thomas; Müller, Erich; Holmberg, Hans-Christer

2009-11-01

Diagonal skiing as a major classical technique has hardly been investigated over the last two decades, although technique and racing velocities have developed substantially. The aims of the present study were to 1) analyse pole and leg kinetics and kinematics during submaximal uphill diagonal roller skiing and 2) identify biomechanical factors related to performance. Twelve elite skiers performed a time to exhaustion (performance) test on a treadmill. Joint kinematics and pole/plantar forces were recorded separately during diagonal roller skiing (9 degrees; 11 km/h). Performance was correlated to cycle length (r = 0.77; P < 0.05), relative leg swing (r = 0.71), and gliding time (r = 0.74), hip flexion range of motion (ROM) during swing (r = 0.73) and knee extension ROM during gliding (r = 0.71). Push-off demonstrated performance correlations for impulse of leg force (r = 0.84), relative duration (r= -0.76) and knee flexion (r = 0.73) and extension ROM (r = 0.74). Relative time to peak pole force was associated with performance (r = 0.73). In summary, diagonal roller skiing performance was linked to 1) longer cycle length, 2) greater impulse of force during a shorter push-off with larger flexion/extension ROMs in leg joints, 3) longer leg swing, and 4) later peak pole force, demonstrating the major key characteristics to be emphasised in training.

Pedicle screw placement using image guided techniques.

PubMed

Merloz, P; Tonetti, J; Pittet, L; Coulomb, M; Lavalleé, S; Sautot, P

1998-09-01

Clinical evaluation of a computer assisted spine surgical system is presented. Eighty pedicle screws were inserted using computer assisted technology in thoracic and lumbar vertebrae for treatment of different types of disorders including fractures, spondylolisthesis, and scoliosis. Fifty-two patients with severe fractures, spondylolisthesis, or pseudoarthrosis of T10 to L5 were treated using a computer assisted technique on 1/2 the patients and performing the screw insertion manually for the other 1/2. At the same time, 28 pedicle screws were inserted in T12 to L4 vertebrae for scoliosis with the help of the computer assisted technique. Surgery was followed in all cases (66 vertebrae; 132 pedicle screws) by postoperative radiographs and computed tomographic examination, on which measurements of screw position relative to pedicle position could be done. For fractures, spondylolisthesis, or pseudarthrosis, comparison between the two groups showed that four screws in 52 (8%) vertebrae had incorrect placement with computer assisted technique whereas 22 screws in 52 (42%) vertebrae had incorrect placement with manual insertion. In patients with scoliosis, four screws in 28 (14%) vertebrae had incorrect placement. In all of the patients (132 pedicle screws) there were no neurologic complications. These results show that a computer assisted technique is much more accurate and safe than manual insertion.

Advantages and Disadvantages of Transtibial, Anteromedial Portal, and Outside-In Femoral Tunnel Drilling in Single-Bundle Anterior Cruciate Ligament Reconstruction: A Systematic Review.

PubMed

Robin, Brett N; Jani, Sunil S; Marvil, Sean C; Reid, John B; Schillhammer, Carl K; Lubowitz, James H

2015-07-01

Controversy exists regarding the best method for creating the knee anterior cruciate ligament (ACL) femoral tunnel or socket. The purpose of this study was to systematically review the risks, benefits, advantages, and disadvantages of the endoscopic transtibial (TT) technique, anteromedial portal technique, outside-in technique, and outside-in retrograde drilling technique for creating the ACL femoral tunnel. A PubMed search of English-language studies published between January 1, 2000, and February 17, 2014, was performed using the following keywords: "anterior cruciate ligament" AND "femoral tunnel." Included were studies reporting risks, benefits, advantages, and/or disadvantages of any ACL femoral technique. In addition, references of included articles were reviewed to identify potential studies missed in the original search. A total of 27 articles were identified through the search. TT technique advantages include familiarity and proven long-term outcomes; disadvantages include the risk of nonanatomic placement because of constrained (TT) drilling. Anteromedial portal technique advantages include unconstrained anatomic placement; disadvantages include technical challenges, short tunnels or sockets, and posterior-wall blowout. Outside-in technique advantages include unconstrained anatomic placement; disadvantages include the need for 2 incisions. Retrograde drilling technique advantages include unconstrained anatomic placement, as well as all-epiphyseal drilling in skeletally immature patients; disadvantages include the need for fluoroscopy for all-epiphyseal drilling. There is no one, single, established "gold-standard" technique for creation of the ACL femoral socket. Four accepted techniques show diverse and subjective advantages, disadvantages, risks, and benefits. Level V, systematic review of Level II through V evidence. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Dual kidney transplant techniques: A systematic review.

PubMed

Cocco, Annelise; Shahrestani, Sara; Cocco, Nicholas; Hameed, Ahmer; Yuen, Lawrence; Ryan, Brendan; Hawthorne, Wayne; Lam, Vincent; Pleass, Henry

2017-08-01

Dual kidney transplantation (DKT) was developed to improve outcomes from transplantation of extended criteria donors (ECD). This study examined which surgical techniques have been reported for DKT and whether any technique had superior patient and graft survival. Electronic databases were searched for published studies mapping to MESH terms: "kidney or renal" AND "transplan*" AND "dual or double." Single case reports, studies of patients less than 18 years old, studies which did not describe the surgical technique, and studies that did not report patient or graft survival were excluded. Fifteen reports of 434 DKT recipients were identified. Three techniques were described: bilateral placement; unilateral placement with separate anastomoses; and unilateral placement with patch anastomoses. Patient survival across all three techniques was over 95% at 1 year, and graft survival was also similar at over 90%. Rates of delayed graft function were between 20% and 30% across all techniques. The three techniques have equivalent delayed graft function as well as patient and graft survival rates. This is an encouraging result as it means that the surgeon can choose to use the technique which is most appropriate for their own skills and for the patient. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Electro-optic control of a PPLN-unpoled LiNbO3 boundary for low-voltage Q switching of an intracavity frequency-doubled Nd3+:YVO4 laser.

PubMed

Torregrosa, A J; Maestre, H; Fernández-Pousa, C R; Pereda, J A; Capmany, J

2009-08-01

We present a simple technique to integrate an electro-optic Q switch in a periodically poled bulk lithium niobate crystal bounded by two unpoled (monodomain) regions. The technique exploits the high sensitivity to low applied electric fields of the total internal reflection condition in the periodic poled-unpoled boundary for the small grazing incidence angles associated with the diffraction of a focused Gaussian beam that propagates in the periodically poled region with its axis parallel to the boundary. When the arrangement is placed intracavity to a 1064 nm diode-pumped Nd(3+):YVO(4) laser, it performs simultaneously as a Q switch and as a second-harmonic generator, with Q switching starting at applied voltages as low as 1 V over a 500 microm thickness and with no additional optical elements.

Thoracic, Lumbar, and Sacral Pedicle Screw Placement Using Stryker-Ziehm Virtual Screw Technology and Navigated Stryker Cordless Driver 3: Technical Note.

PubMed

Satarasinghe, Praveen; Hamilton, Kojo D; Tarver, Michael J; Buchanan, Robert J; Koltz, Michael T

2018-04-17

Utilization of pedicle screws (PS) for spine stabilization is common in spinal surgery. With reliance on visual inspection of anatomical landmarks prior to screw placement, the free-hand technique requires a high level of surgeon skill and precision. Three-dimensional (3D), computer-assisted virtual neuronavigation improves the precision of PS placement and minimization steps. Twenty-three patients with degenerative, traumatic, or neoplastic pathologies received treatment via a novel three-step PS technique that utilizes a navigated power driver in combination with virtual screw technology. (1) Following visualization of neuroanatomy using intraoperative CT, a navigated 3-mm match stick drill bit was inserted at an anatomical entry point with a screen projection showing a virtual screw. (2) A Navigated Stryker Cordless Driver with an appropriate tap was used to access the vertebral body through a pedicle with a screen projection again showing a virtual screw. (3) A Navigated Stryker Cordless Driver with an actual screw was used with a screen projection showing the same virtual screw. One hundred and forty-four consecutive screws were inserted using this three-step, navigated driver, virtual screw technique. Only 1 screw needed intraoperative revision after insertion using the three-step, navigated driver, virtual PS technique. This amounts to a 0.69% revision rate. One hundred percent of patients had intraoperative CT reconstructed images taken to confirm hardware placement. Pedicle screw placement utilizing the Stryker-Ziehm neuronavigation virtual screw technology with a three step, navigated power drill technique is safe and effective.

Analytical transmissibility based transfer path analysis for multi-energy-domain systems using four-pole parameter theory

NASA Astrophysics Data System (ADS)

Mashayekhi, Mohammad Jalali; Behdinan, Kamran

2017-10-01

The increasing demand to minimize undesired vibration and noise levels in several high-tech industries has generated a renewed interest in vibration transfer path analysis. Analyzing vibration transfer paths within a system is of crucial importance in designing an effective vibration isolation strategy. Most of the existing vibration transfer path analysis techniques are empirical which are suitable for diagnosis and troubleshooting purpose. The lack of an analytical transfer path analysis to be used in the design stage is the main motivation behind this research. In this paper an analytical transfer path analysis based on the four-pole theory is proposed for multi-energy-domain systems. Bond graph modeling technique which is an effective approach to model multi-energy-domain systems is used to develop the system model. In this paper an electro-mechanical system is used as a benchmark example to elucidate the effectiveness of the proposed technique. An algorithm to obtain the equivalent four-pole representation of a dynamical systems based on the corresponding bond graph model is also presented in this paper.

Machine learning techniques for fault isolation and sensor placement

NASA Technical Reports Server (NTRS)

Carnes, James R.; Fisher, Douglas H.

1993-01-01

Fault isolation and sensor placement are vital for monitoring and diagnosis. A sensor conveys information about a system's state that guides troubleshooting if problems arise. We are using machine learning methods to uncover behavioral patterns over snapshots of system simulations that will aid fault isolation and sensor placement, with an eye towards minimality, fault coverage, and noise tolerance.

Fracture Resistance of Premolars Restored by Various Types and Placement Techniques of Resin Composites

PubMed Central

Moosavi, Horieh; Zeynali, Mahsa; Pour, Zahra Hosseini

2012-01-01

To verify the fracture resistance of premolars with mesioocclusodistal preparations restored by different resin composites and placement techniques. Sixty premolars were randomly divided into two groups based on type of composite resin: Filtek P60 or Nulite F, and then each group was separated into three subgroups: bulk, centripetal, and fiber insert according to the type of placement method (n = 10). Single-bond adhesive system was used as composite bonding according to the manufacturer's instructions. Specimens were restored in Groups 1, 2, and 3 with Filtek P60 and in Groups 4, 5, and 6 with Nulite F. After being stored 24 hours at 37°C, a 4 mm diameter steel sphere in a universal testing machine was applied on tooth buccal and lingual cusps at a cross-head speed of 5 mm/min until fracture occurred. Groups 3 and 6 showed higher fracture resistance than Groups 1, 2, 4, and 5. Among the placement techniques, the fiber insert method had a significant effect, but the type of composite was ineffective. The insertion technique in contrast to the type of material had a significant influence on the fracture resistance of premolar teeth. PMID:22666255

Use of the Toric Surgical Marker to Aid in Intraoperative Plaque Placement for the USC Eye Physics Plaques to Treat Uveal Melanoma: A New Surgical Technique.

PubMed

Berry, Jesse L; Kim, Jonathan W; Jennelle, Richard; Astrahan, Melvin

2015-09-01

To describe a new surgical technique for intraoperative placement of Eye Physics (EP) plaques for uveal melanoma using a toric marker. A toric marker is designed for cataract surgery to align the axis of astigmatism; its use was modified in this protocol to mark the axis of suture coordinates as calculated by Plaque Simulator (PS) software. The toric marker can be used to localize suture coordinates, in degrees, during intraoperative plaque placement. Linear marking using the toric marker decreases potential inaccuracies associated with the surgeon estimating 'clock-hours' by dot placement. Use of the toric marker aided surgical placement of EP plaques. The EP planning protocol is now designed to display the suture coordinates either by clock-hours or degrees, per surgeon preference. Future research is necessary to determine whether routine use of the toric marker improves operative efficiency. [Ophthalmic Surg Lasers Imaging Retina. 2015;46:866-870.]. Copyright 2015, SLACK Incorporated.

Design of linear quadratic regulators with eigenvalue placement in a specified region

NASA Technical Reports Server (NTRS)

Shieh, Leang-San; Zhen, Liu; Coleman, Norman P.

1990-01-01

Two linear quadratic regulators are developed for placing the closed-loop poles of linear multivariable continuous-time systems within the common region of an open sector, bounded by lines inclined at +/- pi/2k (for a specified integer k not less than 1) from the negative real axis, and the left-hand side of a line parallel to the imaginary axis in the complex s-plane, and simultaneously minimizing a quadratic performance index. The design procedure mainly involves the solution of either Liapunov equations or Riccati equations. The general expression for finding the lower bound of a constant gain gamma is also developed.

Linear quadratic regulators with eigenvalue placement in a specified region

NASA Technical Reports Server (NTRS)

Shieh, Leang S.; Dib, Hani M.; Ganesan, Sekar

1988-01-01

A linear optimal quadratic regulator is developed for optimally placing the closed-loop poles of multivariable continuous-time systems within the common region of an open sector, bounded by lines inclined at + or - pi/2k (k = 2 or 3) from the negative real axis with a sector angle of pi/2 or less, and the left-hand side of a line parallel to the imaginary axis in the complex s-plane. The design method is mainly based on the solution of a linear matrix Liapunov equation, and the resultant closed-loop system with its eigenvalues in the desired region is optimal with respect to a quadratic performance index.

Convergence of fractional adaptive systems using gradient approach.

PubMed

Gallegos, Javier A; Duarte-Mermoud, Manuel A

2017-07-01

Conditions for boundedness and convergence of the output error and the parameter error for various Caputo's fractional order adaptive schemes based on the steepest descent method are derived in this paper. To this aim, the concept of sufficiently exciting signals is introduced, characterized and related to the concept of persistently exciting signals used in the integer order case. An application is designed in adaptive indirect control of integer order systems using fractional equations to adjust parameters. This application is illustrated for a pole placement adaptive problem. Advantages of using fractional adjustment in control adaptive schemes are experimentally obtained. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

The effect of plastic strain on the evolution of crystallographic texture in Zircaloy-2

NASA Astrophysics Data System (ADS)

Ballinger, R. G.; Lucas, G. E.; Pelloux, R. M.

1984-09-01

The evolution of crystallographic texture during plastic deformation was investigated in Zircaloy-2 using X-ray and metallographic techniques. Inverse pole figures, the resolved fraction of basal poles, and the volume fraction of twinned material, were determined as a function of plastic strain for several strain paths and initial textures at 298 K and 623 K. Incremental transverse platic strain ratios ( R) were mesured as a function of plastic strain. Texture rotation occurs early in the deformation process, after as little as 1.5% plastic strain. For compressive plastic strains, the resolved fraction of basal poles increases in the direction parallel to the strain axis. For tensile plastic strains, the resolved fraction of basal poles decreases in the direction parallel to the strain axis. The rate of change of the resolved fraction of basal poles with plastic strain is a function of the initial resolved fraction of basal poles. The texture rotation can be explained by considering the operation of the principal tensile twinning systems, {101¯2}<1¯011>.

A new technique for quantifying symmetry and opening angles in quartz c-axis pole figures: Implications for interpreting the kinematic and thermal properties of rocks

NASA Astrophysics Data System (ADS)

Hunter, N. J. R.; Weinberg, R. F.; Wilson, C. J. L.; Law, R. D.

2018-07-01

Variations in flow kinematics influence the type of crystallographic preferred orientations (CPOs) in plastically deformed quartz, yet we currently lack a robust means of quantifying the diagnostic symmetries that develop in the c-axis (0001) pole figure. In this contribution, we demonstrate how the symmetry of common c-axis topologies may be quantified by analysing the intensity distribution across a line transect of the pole figure margin. A symmetry value (S) measures the relative difference in intensities between marginal girdle maxima in the pole figure, and thus the degree to which the pole figure defines orthorhombic or monoclinic end member symmetries. This provides a semi-quantitative depiction of whether the rocks underwent coaxial or non-coaxial flow, respectively, and may subsequently be used to quantify other topological properties, such as the opening angle of girdle maxima. The open source Matlab® toolbox MTEX is used to quantify pole figure symmetries in quartzite samples from the Main Central Thrust (NW Himalaya) and the Moine Thrust (NW Scotland).

Two-stage implant placement technique for the management of irradiated jaws: An animal study.

PubMed

Aboushelib, Moustafa N; Arnaout, Mohamed A; Elsafi, Mohamed H; Kassem, Youssef M

2017-10-01

Radiotherapy results in diminished bone remodeling capacity and an elevated risk of osteoradionecrosis, which can negatively influence the survival rate of dental implants. Patients receiving radiotherapy are advised not to receive dental implants during or soon after completing their radiotherapy. The purpose of this animal study was to investigate a 2-stage implant placement technique designed to diminish applied trauma on irradiated bone. Two groups of white New Zealand rabbits received radiotherapy in ascending doses (2, 4, 8 Gy), while a nonirradiated group served as control. Three weeks after completion of the last radiotherapy session, one of the irradiated groups and the control group received titanium dental implants bilaterally in the femur head. For the second irradiated group, an osteotomy was performed, and the surgical wound was left to heal for 2 weeks before implant placement. All animals were sacrificed 4 weeks after implant placement, and histomorphometric analysis was used to study bone-implant contact (n=14, α=.05). Statistical analysis revealed significantly higher (F=159, P<.001) bone-implant contact in the 2-stage (40.2 ±1.9) implant placement technique than in the immediately placed implants (21.2 ±2.3) in irradiated bone. Both of the groups had a significantly lower bone-to-implant contact ratio than the non-irradiated control (64.2 ±3.8). Within the limitations of this animal study, the 2-stage implant placement technique could be used to reduce trauma in irradiated bone and to improve wound healing around dental implants. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Evaluation of the clavicular tunnel placement on coracoclavicular ligament reconstruction for acromioclavicular dislocations: a finite element analysis.

PubMed

Kocadal, Onur; Yüksel, Korcan; Güven, Melih

2018-01-27

The two-tunnel coracoclavicular ligament reconstruction (CLR) technique is one of the treatment approaches commonly used in the surgical treatment of acromioclavicular (AC) injuries. Clavicular tunnel malposition is one of the major causes of failure in coracoclavicular ligament reconstruction. The main purpose of this study was to investigate the effects of clavicular tunnel placement on tendon loading in the CLR technique with finite element analysis. Models of clavicle and scapula were constructed using computerized tomography images. Two clavicular bone tunnel reconstruction models were created with the tendon passing through the conoid and trapezoid tunnels. Four models based on the tunnel ratio (TR) method and defined as primary, anatomic, medialized, and lateralized were constructed to evaluate the effect of tunnel placement on loading conditions during tendon graft. All models were loaded by insertion from the trapezius and sternocleidomastoid muscles. The loading on the tendon were evaluated with the finite element analysis. The highest load value measured on the tendon was in the anatomic model (0.789 kPa), and the lowest load value (0.598 kPa) was measured in the lateralized tunnel model. The load value of the primary model was (0.657 kPa), and the medialized model's value was (0.752 kPa). In two-tunnel CLR technique, tendon loadings are related to tunnel placement. Medialized tunnel placement increases tendon loading. The TR method may be an appropriate option for determining tunnel placement.

Calcaneal traction pin placement simplified: a cadaveric study.

PubMed

Kwon, John Y; Ellington, J Kent; Marsland, Daniel; Gupta, Sanjeev

2011-06-01

The tibial neurovascular bundle and sural nerve are at risk with errant pin placement during transcalcaneal pin placement. The purpose of this study was to determine a relative safe zone using a single osseous landmark to establish a technique applicable in the presence of trauma. We describe the neural anatomy anatomically and radiographically, giving surgeons a reliable and relatively safe technique for transcalcaneal pin placement. Twenty-four cadavers were dissected for the major medial neurovascular structures and the sural nerve. The closest distance from the neurovascular structures to the posterior inferior calcaneus was measured. The mean distance from the posterior inferior calcaneus to the closest major medial neurovascular structure was 3.4 cm (SD ± 0.36; range, 2.6 to 4.1 cm). The mean distance to the sural nerve was 3.4 cm (SD ± 0.54; range, 2.3 to 4.6 cm). According to the 95% confidence intervals, a relative safe zone of 3.1 cm as a radius from the posterior inferior calcaneus was determined. A relatively safe zone of 3.1 cm based on 95% confidence intervals as described as a radius from the posterior inferior calcaneus can be used for transcalcaneal pin placement in most cases without injury to the medial neurovascular bundle or sural nerve. However anatomic variation may result in the neurovascular bundle being within this zone. We describe a surgical technique for reliable placement of a transcalcaneal pin within this relative safe zone and a safe distance from the closest neurovascular structure.

Ridge expansion and immediate placement with piezosurgery and screw expanders in atrophic maxillary sites: two case reports.

PubMed

Kelly, Andrew; Flanagan, Dennis

2013-02-01

Endosseous dental implants may require bone augmentation before implant placement. Herein is described an approach to edentulous ridge expansion with the use of piezosurgery and immediate placement of implants. This may allow for a shortened treatment time and the elimination of donor-site morbidity. Two cases are reported. This technique uses a piezoelectric device to cut the crestal and proximal facial cortices. Space is then created with motorized osteotomes to widen the split ridge. This technique allows for expansion of narrow, anatomically limiting, atrophic ridges, creating space for immediate implant placement. The facial and lingual cortices provide support with vital osteocytes for osteogenesis. The 2 patients presented had adequate bone height for implant placement but narrow edentulous ridges. In patient 1 at site #11, the ridge crest was 3.12 mm thick and was expanded to accept a 4.3 mm × 13 mm implant. The resulting ridge width was 8.88 mm, which was verified using cone beam computerized tomography (CBCT). In patient 2 at site #8 and site #9, the narrow ridge was expanded using the same technique to accept 2 adjacent 3.5 mm × 14 mm implants. The implants were restored to a functional and esthetic outcome.

Visually guided tube thoracostomy insertion comparison to standard of care in a large animal model.

PubMed

Hernandez, Matthew C; Vogelsang, David; Anderson, Jeff R; Thiels, Cornelius A; Beilman, Gregory; Zielinski, Martin D; Aho, Johnathon M

2017-04-01

Tube thoracostomy (TT) is a lifesaving procedure for a variety of thoracic pathologies. The most commonly utilized method for placement involves open dissection and blind insertion. Image guided placement is commonly utilized but is limited by an inability to see distal placement location. Unfortunately, TT is not without complications. We aim to demonstrate the feasibility of a disposable device to allow for visually directed TT placement compared to the standard of care in a large animal model. Three swine were sequentially orotracheally intubated and anesthetized. TT was conducted utilizing a novel visualization device, tube thoracostomy visual trocar (TTVT) and standard of care (open technique). Position of the TT in the chest cavity were recorded using direct thoracoscopic inspection and radiographic imaging with the operator blinded to results. Complications were evaluated using a validated complication grading system. Standard descriptive statistical analyses were performed. Thirty TT were placed, 15 using TTVT technique, 15 using standard of care open technique. All of the TT placed using TTVT were without complication and in optimal position. Conversely, 27% of TT placed using standard of care open technique resulted in complications. Necropsy revealed no injury to intrathoracic organs. Visual directed TT placement using TTVT is feasible and non-inferior to the standard of care in a large animal model. This improvement in instrumentation has the potential to greatly improve the safety of TT. Further study in humans is required. Therapeutic Level II. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oscillating behavior of Clostridium difficile Min proteins in Bacillus subtilis.

PubMed

Makroczyová, Jana; Jamroškovič, Ján; Krascsenitsová, Eva; Labajová, Nad'a; Barák, Imrich

2016-06-01

In rod-shaped bacteria, the proper placement of the division septum at the midcell relies, at least partially, on the proteins of the Min system as an inhibitor of cell division. The main principle of Min system function involves the formation of an inhibitor gradient along the cell axis; however, the establishment of this gradient differs between two well-studied gram-negative and gram-positive bacteria. While in gram-negative Escherichia coli, the Min system undergoes pole-to-pole oscillation, in gram-positive Bacillus subtilis, proper spatial inhibition is achieved by the preferential attraction of the Min proteins to the cell poles. Nevertheless, when E.coli Min proteins are inserted into B.subtilis cells, they still oscillate, which negatively affects asymmetric septation during sporulation in this organism. Interestingly, homologs of both Min systems were found to be present in various combinations in the genomes of anaerobic and endospore-forming Clostridia, including the pathogenic Clostridium difficile. Here, we have investigated the localization and behavior of C.difficile Min protein homologs and showed that MinDE proteins of C.difficile can oscillate when expressed together in B.subtilis cells. We have also investigated the effects of this oscillation on B.subtilis sporulation, and observed decreased sporulation efficiency in strains harboring the MinDE genes. Additionally, we have evaluated the effects of C.difficile Min protein expression on vegetative division in this heterologous host. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Intrauterine transfusion with the use of phased array ultrasonography: a new technique.

PubMed

Frigoletto, F D; Birnholz, J C; Rothchild, S B; Finberg, H J; Umansky, I

1978-06-01

Continuous ultrasonic observation of needle placement for aspiration, biopsy, or catheter placement is a novel and specific use of phased array imaging. In the case of IUTx, catheter placement into the fetal peritoneal space is accomplished rapidly, with reduced risk of fetal trauma, and without exposure to ionizing radiation. Experience with 27 transfusions in 11 patients is presented.

Parallel algorithms for placement and routing in VLSI design. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Brouwer, Randall Jay

1991-01-01

The computational requirements for high quality synthesis, analysis, and verification of very large scale integration (VLSI) designs have rapidly increased with the fast growing complexity of these designs. Research in the past has focused on the development of heuristic algorithms, special purpose hardware accelerators, or parallel algorithms for the numerous design tasks to decrease the time required for solution. Two new parallel algorithms are proposed for two VLSI synthesis tasks, standard cell placement and global routing. The first algorithm, a parallel algorithm for global routing, uses hierarchical techniques to decompose the routing problem into independent routing subproblems that are solved in parallel. Results are then presented which compare the routing quality to the results of other published global routers and which evaluate the speedups attained. The second algorithm, a parallel algorithm for cell placement and global routing, hierarchically integrates a quadrisection placement algorithm, a bisection placement algorithm, and the previous global routing algorithm. Unique partitioning techniques are used to decompose the various stages of the algorithm into independent tasks which can be evaluated in parallel. Finally, results are presented which evaluate the various algorithm alternatives and compare the algorithm performance to other placement programs. Measurements are presented on the parallel speedups available.

Nearshore Placement Techniques in Southern Lake Michigan

DTIC Science & Technology

2018-03-01

ER D C /C HL T R- 18 -3 Regional Sediment Management (RSM) Program Nearshore Placement Techniques in Southern Lake Michigan Co as ta...online library at http://acwc.sdp.sirsi.net/client/default. Regional Sediment Management (RSM) Program ERDC/CHL TR-18-3 March 2018 Nearshore...This study was conducted for Headquarters, U.S. Army Corps of Engineers (HQUSACE), Washington, DC, under the USACE Regional Sediment Management

Complications of acucise endopyelotomy.

PubMed

Kim, F J; Herrell, S D; Jahoda, A E; Albala, D M

1998-10-01

Endoscopic management of ureteropelvic junction (UPJ) obstruction has a success rate of 80% to 86%. We have been performing a ureteral cutting balloon procedure under fluoroscopic control (Acucise endopyelotomy) for UPJ obstruction at Loyola University Medical Center since 1991. The overall success rate in 77 patients was 78%. All patients had a preoperative intravenous urogram or a retrograde pyelogram, but none had vascular imaging studies. Acucise endopyelotomy consisted of a posterolateral incision of the UPJ and placement of an endopyelotomy or double-J stent. Foley catheter placement at the end of the procedure demonstrated significant gross hematuria in three patients (4%). All three remained hemodynamically stable but with significant drops in postprocedure hemoglobin levels, which necessitated blood transfusion. Aggressive management included angiographic studies and embolization of lower-pole branching arteries in two patients (3%). One patient stopped bleeding after being given two units of blood. None of the patients required an open exploratory procedure. Although the risk of vascular injury is low with Acucise endopyelotomy, prolonged postoperative gross hematuria does mandate investigation and observation. Angiographic embolization appears to be the therapeutic modality of choice for patients with hemorrhagic complications after an Acucise endopyelotomy.

Central venous access in children: indications, devices, and risks.

PubMed

Ares, Guillermo; Hunter, Catherine J

2017-06-01

Central venous catheters (CVCs) have a prominent role in the diagnostic and therapy of neonates and children. Herein, we describe the multiple indications for CVC use and the different devices available for central venous access. Given the prevalent use of CVCs, healthcare systems are focused on reducing complications from their use, particularly central line-associated bloodstream infections (CLABSIs). The most up-to-date information available sheds light on best practices and future areas of investigation. Large systematic reviews of randomized trials suggest that ultrasound guidance for placement of CVCs in children is safer than using blind technique, at least for internal jugular vein access. Appropriate catheter tip placement is associated with decreased complications. Furthermore, the prophylactic use of ethanol lock between cycles of parenteral nutrition administration has reduced the rates of CLABSI. A recent randomized trial in pediatric CVCs showed a benefit with antibiotic-coated CVCs. Based on the available evidence, multiple techniques for CVC placement are still valid, including the landmark technique based on practitioner experience, but ultrasound guidance has been shown to decrease complications from line placement. Adherence to CVC care protocols is essential in reducing infectious complications.

The influence of different placement techniques on the microtensile bond strength of low-shrink silorane composite bonded to Class I cavities.

PubMed

Almeida e Silva, J S; Rolla, Juliana Nunes; Baratieri, Luiz Narciso; Monteiro, Sylvio

2011-01-01

The aim of this in vitro study was to evaluate the microtensile bond strength (µTBS) of a low-shrink silorane-based composite (Filtek Silorane) and a methacrylate-based composite (Filtek Z250) to the bottom dentin of a Class I cavity using different placement techniques. Twelve third molars were used. Standard, box-type Class I cavities (6.0 x 4.0 x 2.5 mm) were prepared at the occlusal crown center, with the pulpal floor ending approximately at the midcoronal dentin. The teeth were then randomly divided into four groups, according to each placement technique: ZI--Filtek Z250 placed incrementally; ZB--Filtek Z250 placed in bulk; SI--Filtek Silorane placed incrementally; and SB--Filtek Silorane placed in bulk. Each restored third molar was subjected to microtensile bond testing after 24 hours of storage in distilled water at 37 degrees C. After storage, each molar was longitudinally sectioned in both axes to obtain rectangular sticks with an approximate 0.49 mm2 cross-sectional area. Data were analyzed by one-way ANOVA followed by a Tukey post hoc test (P = 0.05). After debonding, the failure modes were analyzed using a stereomicroscope. The ZI group (72.6 MPa) showed the highest µTBS, followed by the ZB group (60.2 MPa), while the SI (34.4 MPa) and SB (42.6 MPa) groups demonstrated statistically significant lower bond strengths. The type of placement technique did not influence the µTBS of silorane-based composites to the bottom dentin of Class I cavities. The methacrylate-based composite showed superior performance, regardless of the placement technique.

Cannula Versus Sharp Needle for Placement of Soft Tissue Fillers: An Observational Cadaver Study.

PubMed

van Loghem, Jani A J; Humzah, Dalvi; Kerscher, Martina

2017-12-13

Soft-tissue fillers have become important products for facial rejuvenation. Deep fat compartments and facial bones lose volume during the natural aging process. For the most natural-looking results, deep volumetric injections at strategic sites are therefore preferred. Supraperiosteal placement is performed with a sharp needle or a non-traumatic cannula. The primary objective was to determine whether there is a difference in precision between supraperiosteal placement with a sharp needle compared with a non-traumatic cannula in cadaver specimens. A secondary objective was to analyze the safety profiles of both injection techniques. Cadaver heads were injected with dye material and soft-tissue fillers at multiple aesthetic facial sites on the supraperiosteum and subsequently dissected for observation of dye and filler placement. The non-traumatic cannula technique resulted in product being confined to the deep anatomic layers. In contrast, with the sharp needle technique, material was placed in multiple anatomic layers, from the periosteum to more superficial skin layers. For both techniques results were consistent for all facial sites. Although direct extrapolation from cadavers to the in vivo situation cannot be made, cannulae showed more precision in placement of product. With the sharp needle, the material was injected on the periosteum, and then migrated in a retrograde direction along the trajectory of the needle path, ending up in multiple anatomic layers. The sharp needle technique also showed a higher complication risk with intra-arterial injection occurring, even though the needle tip was positioned on the periosteum and the product was injected with the needle in constant contact with the periosteum. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

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

Heberlein, Wolf E., E-mail: weheberlein@uams.edu; Goodwin, Whitney J.; Wood, Clint E.

Purpose: Our study evaluated techniques for percutaneous gastrostomy (G)-tube placement without the use of a nasogastric (NG) tube. Instead, direct puncture of a physiologic air bubble or effervescent-enhanced gastric bubble distention was performed in patients with upper digestive tract obstruction (UDTO) or psychological objections to NG tubes. Materials and Methods: A total of 886 patients underwent G-tube placement in our department during a period of 7 years. We present our series of 85 (9.6%) consecutive patients who underwent percutaneous G-tube placement without use of an NG tube. Results: Of these 85 patients, fluoroscopic guided access was attempted by direct puncturemore » of a physiologically present gastric air bubble in 24 (28%) cases. Puncture of an effervescent-induced large gastric air bubble was performed in 61 (72%) patients. Altogether, 82 (97%) of 85 G tubes were successfully placed in this fashion. The three failures comprised refusal of effervescent, vomiting of effervescent, and one initial tube misplacement when a deviation from our standard technique occurred. Conclusion: The described techniques compare favorably with published large series on G-tube placement with an NG tube in place. The techniques are especially suited for patients with UDTO due to head, neck, or esophageal malignancies, but they should be considered as an alternative in all patients. Direct puncture of effervescent-enhanced gastric bubble distention is a safe, patient-friendly and effective technique.« less

The physiological and biomechanical contributions of poling to roller ski skating.

PubMed

Sandbakk, Øyvind; Ettema, Gertjan; Holmberg, Hans-Christer

2013-08-01

Poling is considered to make a significant contribution to cross-country skiing with the skating technique. To better understand this contribution, the current investigation compared roller ski skating on a treadmill with the so-called G3 skating technique with (G3-P) and without poling (G3-NP). Seven male elite skiers performed 5-min submaximal tests at 8, 12, and 15 km h(-1), as well as an incremental test to exhaustion with both techniques on a 5 % incline. Ventilatory variables were assessed by open-circuit indirect calorimetry and three-dimensional kinematics analyzed using the Qualisys Pro Reflex system. G3-P was associated with approximately 15 % higher peak velocity and 10 % higher peak oxygen uptake than G3-NP in the incremental test (both P < 0.01). All ventilatory variables, as well as heart rate and blood lactate concentration were lower with G3-P as compared to G3-NP at 12 and 15 km h(-1) (all P < 0.01). Gross efficiency (i.e., the ratio of work rate to metabolic rate) at 12 km h(-1) was higher in G3-P (14.9 %) than G3-NP (13.5 %) (P < 0.01). Moreover, with G3-P cycle time and length were both 30 % longer, with correspondingly reduced cycle rates (all P < 0.01). In addition, the ski gliding and swing phases were longer and the angle between the skis smaller with G3-P (both P < 0.01), whereas the push-off time was independent of technique and velocity. Taken together, these results indicate that poling makes an important contribution to propulsion and velocity during ski skating, specifically by enhancing peak oxygen uptake, skiing efficiency and associated biomechanical variables.

Placement of Upper Extremity Arteriovenous Access in Patients with Central Venous Occlusions: A Novel Technique.

PubMed

Murga, Allen G; Chiriano, Jason T; Bianchi, Christian; Sheng, Neha; Patel, Sheela; Abou-Zamzam, Ahmed M; Teruya, Theodore H

2017-07-01

Central venous occlusion is a common occurrence in patients with end-stage renal disease. Placement of upper extremity arteriovenous access in patients with occlusion of the brachiocephalic veins is often not an option. Avoidance of lower extremity vascular access can decrease morbidity and infection. The central venous lesions were crossed centrally via femoral access. The wire was retrieved in the neck extravascularly. A Hemodialysis Reliable Outflow catheter was then placed in the right atrium and completed with an arterial anastomosis. We describe a novel technique for placing upper extremity arteriovenous access in patients with occlusion of the brachiocephalic veins. This technique was utilized in 3 patients. The technical success was 100%. The placement of upper extremity arteriovenous access in patients with central venous occlusions is technically feasible. Published by Elsevier Inc.

Accuracy of frame-based stereotactic depth electrode implantation during craniotomy for subdural grid placement.

PubMed

Munyon, Charles N; Koubeissi, Mohamad Z; Syed, Tanvir U; Lüders, Hans O; Miller, Jonathan P

2013-01-01

Frame-based stereotaxy and open craniotomy may seem mutually exclusive, but invasive electrophysiological monitoring can require broad sampling of the cortex and precise targeting of deeper structures. The purpose of this study is to describe simultaneous frame-based insertion of depth electrodes and craniotomy for placement of subdural grids through a single surgical field and to determine the accuracy of depth electrodes placed using this technique. A total of 6 patients with intractable epilepsy underwent placement of a stereotactic frame with the center of the planned cranial flap equidistant from the fixation posts. After volumetric imaging, craniotomy for placement of subdural grids was performed. Depth electrodes were placed using frame-based stereotaxy. Postoperative CT determined the accuracy of electrode placement. A total of 31 depth electrodes were placed. Mean distance of distal electrode contact from the target was 1.0 ± 0.15 mm. Error was correlated to distance to target, with an additional 0.35 mm error for each centimeter (r = 0.635, p < 0.001); when corrected, there was no difference in accuracy based on target structure or method of placement (prior to craniotomy vs. through grid, p = 0.23). The described technique for craniotomy through a stereotactic frame allows placement of subdural grids and depth electrodes without sacrificing the accuracy of a frame or requiring staged procedures.

“Five on a dice” port placement for robot-assisted thoracoscopic right upper lobectomy using robotic stapler

PubMed Central

Chan, Edward Y.

2017-01-01

Early versions of the da Vinci robot system (S and Si) have been used to perform pulmonary lung resection with severe limitations. The lack of a vascular robot stapler required the presence of a trained bedside assistant whose role was to place, manipulate and fire the stapler around major vascular structures. Thus, the techniques developed for the Si robot required a skilled bedside assistant to perform stapling of the hilar structure and manipulation of the lung. With the advent of the da Vinci Xi system with a vascular robot stapler, we postulated that we could develop a new port placement and technique to provide total control for the surgeon during the pulmonary lung resection. We found that the “five on a dice” port placement and technique allows for minimal assistance during the lobectomy with full control by the surgeon. This technique uses the full capability of the Xi robot to make the robot-assisted lobectomy a safe and ergonomic operation. PMID:29312746

"Five on a dice" port placement for robot-assisted thoracoscopic right upper lobectomy using robotic stapler.

PubMed

Kim, Min P; Chan, Edward Y

2017-12-01

Early versions of the da Vinci robot system (S and Si) have been used to perform pulmonary lung resection with severe limitations. The lack of a vascular robot stapler required the presence of a trained bedside assistant whose role was to place, manipulate and fire the stapler around major vascular structures. Thus, the techniques developed for the Si robot required a skilled bedside assistant to perform stapling of the hilar structure and manipulation of the lung. With the advent of the da Vinci Xi system with a vascular robot stapler, we postulated that we could develop a new port placement and technique to provide total control for the surgeon during the pulmonary lung resection. We found that the "five on a dice" port placement and technique allows for minimal assistance during the lobectomy with full control by the surgeon. This technique uses the full capability of the Xi robot to make the robot-assisted lobectomy a safe and ergonomic operation.

Searching for Water Ice at the Lunar North Pole Using High-Resolution Images and Radar

NASA Technical Reports Server (NTRS)

Mitchell, J. L.; Lawrence, S. J.; Robinson, M. S.; Speyerer, E. J.; Denevi, B. W.

2017-01-01

Permanently shadowed regions (PSRs) at the lunar poles are potential reservoirs of frozen volatiles, and are therefore high-priority exploration targets. PSRs trap water and other volatiles because their annual maximum temperatures (40-100K) are lower than the sublimation temperatures of these species (i.e. H2O approx.104K). Previous studies using various remote sensing techniques have not been able to definitively characterize the distribution or abundance of ice in lunar PSRs. The purpose of this study is to search for signs of ice in PSRs using two complimentary remote sensing techniques: radar and visible images.

Design, test, and evaluation of three active flutter suppression controllers

NASA Technical Reports Server (NTRS)

Adams, William M., Jr.; Christhilf, David M.; Waszak, Martin R.; Mukhopadhyay, Vivek; Srinathkumar, S.

1992-01-01

Three control law design techniques for flutter suppression are presented. Each technique uses multiple control surfaces and/or sensors. The first method uses traditional tools (such as pole/zero loci and Nyquist diagrams) for producing a controller that has minimal complexity and which is sufficiently robust to handle plant uncertainty. The second procedure uses linear combinations of several accelerometer signals and dynamic compensation to synthesize the model rate of the critical mode for feedback to the distributed control surfaces. The third technique starts with a minimum-energy linear quadratic Gaussian controller, iteratively modifies intensity matrices corresponding to input and output noise, and applies controller order reduction to achieve a low-order, robust controller. The resulting designs were implemented digitally and tested subsonically on the active flexible wing wind-tunnel model in the Langley Transonic Dynamics Tunnel. Only the traditional pole/zero loci design was sufficiently robust to errors in the nominal plant to successfully suppress flutter during the test. The traditional pole/zero loci design provided simultaneous suppression of symmetric and antisymmetric flutter with a 24-percent increase in attainable dynamic pressure. Posttest analyses are shown which illustrate the problems encountered with the other laws.

Immediate Placement of Ultrawide-Diameter Implants in Molar Sockets: Description of a Recommended Technique.

PubMed

Hattingh, André C; De Bruyn, Hugo; Ackermann, Andrew; Vandeweghe, Stefan

Immediate implant placement is performed less frequently in molar extraction sockets than in single root sockets. This is mainly due to the tripodal anatomical configuration of molar roots, which is perceived as complex and therefore unsuitable. The mechanical burden of molar sites, combined with much larger socket dimensions, make it amenable to the use of ultrawide-diameter dental implants. This article describes a practical, sequenced technique that can be used predictably for immediate implant placement in maxillary and mandibular first molar sockets, using a dry skull model for clarification. This detailed description is based on the experience of more than 580 clinical cases over a 10-year period.

The one step fermionic ladder

NASA Astrophysics Data System (ADS)

Das, Joy Prakash; Setlur, Girish S.

2017-10-01

The one step fermionic ladder refers to two parallel Luttinger Liquids (poles of the ladder) placed such that there is a finite probability of electrons hopping between the two poles at a pair of opposing points along each of the poles. The many-body Green function for such a system is calculated in presence of forward scattering interactions using the powerful non-chiral bosonization technique (NCBT). This technique is based on a non-standard harmonic analysis of the rapidly varying parts of the density fields appropriate for the study of strongly inhomogeneous ladder systems. The closed analytical expression for the correlation function obtained from NCBT is nothing but the series involving the RPA (Random Phase Approximation) diagrams in powers of the forward scattering coupling strength resummed to include only the most singular terms with the source of inhomogeneities treated exactly. Finally the correlation functions are used to study physical phenomena such as Friedel oscillations and the conductance of such systems with the potential difference applied across various ends.

Internal fixation of displaced inferior pole of the patella fractures using vertical wiring augmented with Krachow suturing.

PubMed

Oh, Hyoung-Keun; Choo, Suk-Kyu; Kim, Ji-Wan; Lee, Mark

2015-12-01

We present the surgical technique of separate vertical wiring for displaced inferior pole fractures of the patella combined with Krachow suture and report the surgical outcomes. Between September 2007 to May 2012, 11 consecutive patients (mean age, 54.6 years) with inferior pole fractures of the patella (AO/OTA 34-A1) were retrospectively enrolled in this study. Through longitudinal incision, all patients underwent open reduction and internal fixation by separate vertical wiring combined with Krackow suture. The range of motion, loss of fixation, and Bostman score were primary outcome measures. The union time was 10 weeks after surgery on average (range: 8-12). No patient had nonunion, loss of reduction and wire breakage. There was no case of wound problem and irritation from the implant. At final follow-up, the average range of motion arc was 129.4° (range: 120-140). The mean Bostman score at last follow-up was 29.6 points (range: 28-30) and graded excellent in all cases. Separate vertical wiring combined with Krackow suture for inferior pole fractures of the patella is a useful technique that is easy to perform and can provide stable fixation with excellent results in knee function. Copyright © 2015 Elsevier Ltd. All rights reserved.

A new technique of deploying dynamic y stent using flexible bronchoscope, video laryngoscope, and laryngeal mask airway.

PubMed

Obeidat, Shadi; Badin, Shadi; Khawaja, Imran

2010-04-01

Dynamic Y stents are used in tracheobronchial obstruction, tracheal stenosis, and tracheomalacia. Placement may be difficult and is usually accomplished using a rigid grasping forceps (under fluoroscopic guidance) or a rigid bronchoscope. We report using a new stent placement technique on an elderly patient with a central tracheobronchial tumor. It included using a flexible bronchoscope, video laryngoscope, and laryngeal mask airway. The new technique we used has the advantages of continuous direct endoscopic visualization during stent advancement and manipulation, and securing the airways with a laryngeal mask airway at the same time. This technique eliminates the need for intraoperative fluoroscopy.

Robotic-assisted laparoscopic prostatectomy in umbilical hernia patients: University of California, Irvine, technique for port placement and repair.

PubMed

Kim, William; Abdelshehid, Corollos; Lee, Hak J; Ahlering, Thomas

2012-06-01

To discuss a technique currently used at our institution for the management of umbilical hernias during robot-assisted laparoscopic prostatectomy. As more patients undergo robot-assisted radical prostatectomy, there will be an increase in patients who qualify for robotic surgery with comorbidities. This technique has been utilized in clinically localized prostate cancer patients with umbilical hernias using the da Vinci Surgical System and standard laparoscopic instrumentation. Port placements and closures were performed by a resident assistant and a nurse at the operating table. The prostatectomy was performed by a single experienced surgeon at the console. Currently, no data are available regarding patients with umbilical hernias undergoing robotic prostatectomy. We reviewed our technique of port placement for patients with a pre-existing umbilical hernia undergoing robot-assisted laparoscopic prostatectomy. This technique allows for a reduction of the umbilical hernia, the use of the fascial defect as a robotic port, and the removal of the prostate by way of transverse incision and transverse repair. In our experience, this technique is feasible and reproducible for any small or large umbilical hernia. Copyright © 2012 Elsevier Inc. All rights reserved.

Improved spatial coverage for brain 3D PRESS MRSI by automatic placement of outer-volume suppression saturation bands.

PubMed

Ozhinsky, Eugene; Vigneron, Daniel B; Nelson, Sarah J

2011-04-01

To develop a technique for optimizing coverage of brain 3D (1) H magnetic resonance spectroscopic imaging (MRSI) by automatic placement of outer-volume suppression (OVS) saturation bands (sat bands) and to compare the performance for point-resolved spectroscopic sequence (PRESS) MRSI protocols with manual and automatic placement of sat bands. The automated OVS procedure includes the acquisition of anatomic images from the head, obtaining brain and lipid tissue maps, calculating optimal sat band placement, and then using those optimized parameters during the MRSI acquisition. The data were analyzed to quantify brain coverage volume and data quality. 3D PRESS MRSI data were acquired from three healthy volunteers and 29 patients using protocols that included either manual or automatic sat band placement. On average, the automatic sat band placement allowed the acquisition of PRESS MRSI data from 2.7 times larger brain volumes than the conventional method while maintaining data quality. The technique developed helps solve two of the most significant problems with brain PRESS MRSI acquisitions: limited brain coverage and difficulty in prescription. This new method will facilitate routine clinical brain 3D MRSI exams and will be important for performing serial evaluation of response to therapy in patients with brain tumors and other neurological diseases. Copyright © 2011 Wiley-Liss, Inc.

The difficult ureter: what is the incidence of pre-stenting?

PubMed

Cetti, R J; Biers, S; Keoghane, S R

2011-01-01

Difficulty may be encountered with retrograde access for rigid and flexible ureterorenoscopy (URS) due to anatomic abnormalities, a narrow ureteric lumen, tortuous ureteric path or previous instrumentation. Ureteric dilatation using a balloon or tapered dilator can occasionally fail and will usually lead to the placement of a ureteric stent. We present our experience and incidence of pre-stenting after failed standard access and dilatation techniques, the aim being to quote a figure for the patient at the time of consent. Data were collected prospectively from a single surgeon at a regional tertiary referral stone unit. The outcomes of those patients pre-stented, for failed access, were recorded. Between December 2007 and December 2008, a total of 119 patients underwent flexible and rigid URS. Mean patient age was 49 years (range, 19-86 years). Of these, 107 cases were undertaken for urolithiasis and 12 cases for diagnosis of upper tract malignancy. 12% (13/107) of cases were for pain and non-diagnostic imaging and 8.4% (9/107) of patients were pre-stented because of failed access, without complication, and subsequently had successful interval treatment. Of the remaining successful cases of confirmed urolithiasis, 33% (28/85) and 67% (56/85) were undertaken for ureteric and renal calculi, respectively. Stone clearance rates were 83% (19/23) and 75% (3/4) for lower pole renal calculi 5-10 mm and > 10 mm in size, respectively. The overall clearance rate for lower pole calculi was 81% (22/27). The ureteric stone clearance rate was 86% (24/28) rising to 92% (24/26) in those solitary stones less than 10 mm in size. The incidence of ureteric pre-stenting in a tertiary referral unit was 8% and should be considered and indeed discussed with patients when obtaining pre-operative consent, especially for purely elective, non-urgent, upper tract cases. The alternative for these difficult, tight ureters is extensive balloon dilatation, with the risk of trauma and the potential for long-term stricture formation.

Preoperative fiducial coil placement facilitates robot-assisted laparoscopic excision of retroperitoneal small solitary metastasis of kidney cancer.

PubMed

Agrawal, Vineet; Sharma, Ashwani; Wu, Guan

2014-11-01

Image-guided fiducial markers are being used in surgery, especially in spine and breast surgery, and radiotherapy, allowing localization of tumor sites precisely. We report a case of fiducial coil use in a man undergoing a robot-assisted laparoscopic resection of a metastatic nodule under the ipsilateral diaphragm after robot-assisted partial nephrectomy performed 2 years ago for a left upper pole renal tumor. The fiducial coil facilitated the localization of the lesion, which would otherwise have been challenging because of its small size and location. In addition, the fiducial coil was helpful to avoid cutting into the lesion directly. Copyright © 2014 Elsevier Inc. All rights reserved.

Piezoelectric pushers for active vibration control of rotating machinery

NASA Technical Reports Server (NTRS)

Palazzolo, A. B.; Kascak, A. F.; Lin, R. R.; Montague, J.; Alexander, R. M.

1989-01-01

The active control of rotordynamic vibrations and stability by magnetic bearings and electromagnetic shakers was discussed extensively in the literature. These devices, though effective, are usually large in volume and add significant weight to the stator. The use of piezoelectric pushers may provide similar degrees of effectiveness in light, compact packages. Analyses are contained which extend quadratic regulator, pole placement and derivative feedback control methods to the prescribed displacement character of piezoelectric pushers. The structural stiffness of the pusher is also included in the theory. Tests are currently being conducted at NASA Lewis Research Center with piezoelectric pusher-based active vibration control. Results performed on the NASA test rig as preliminary verification of the related theory are presented.

Overview of Krylov subspace methods with applications to control problems

NASA Technical Reports Server (NTRS)

Saad, Youcef

1989-01-01

An overview of projection methods based on Krylov subspaces are given with emphasis on their application to solving matrix equations that arise in control problems. The main idea of Krylov subspace methods is to generate a basis of the Krylov subspace Span and seek an approximate solution the the original problem from this subspace. Thus, the original matrix problem of size N is approximated by one of dimension m typically much smaller than N. Krylov subspace methods have been very successful in solving linear systems and eigenvalue problems and are now just becoming popular for solving nonlinear equations. It is shown how they can be used to solve partial pole placement problems, Sylvester's equation, and Lyapunov's equation.

Novel technique for preoperative pedicle localization in spinal surgery with challenging anatomy.

PubMed

Young, Richard M; Prasad, Vikram; Wind, Joshua J; Olan, Wayne; Caputy, Anthony J

2014-04-01

Accurately localizing a spine level in the thoracic spine is often not easily achieved with the existing imaging modalities available in the operating room. The coordination of the preoperative imaging pathology with intraoperative imaging is even more difficult in patients with challenging anatomy. Using standard percutaneous techniques, the authors placed a radiopaque embolization coil into the pedicle of interest under biplanar fluoroscopy in 1 patient. Thoracic spine MRI along with scout MRI was then performed to confirm coil marker placement in relation to the actual spine pathology prior to surgical intervention. No complications were observed during placement of the radiopaque marker. Intraoperatively, the marker was immediately and easily visualized, leading to a confident identification of the correct thoracic spinal level. The preoperative placement of a radiopaque marker into the vertebral pedicle of the identified pathological level combined with postplacement MRI verification provides an advantage over previously proposed techniques in the literature.

Benefits of Ultrasound Imaging for Placement of Caudal Epidural Blockade in 3 Pediatric Patients: A Case Report.

PubMed

Sinskey, Jina L; Vecchione, Tricia M; Ekstrom, Benjamin G; Boretsky, Karen

2018-06-01

Pediatric caudal epidural blockade, the most common pediatric regional anesthetic, is classically placed using surface landmark technique with infrequent use of ultrasound guidance. We present 3 cases where ultrasound guidance facilitated successful placement and helped prevent complications. One infant had an unanticipated S5 dural sac necessitating needle redirection to avoid subarachnoid injection. A 5-year old had proper needle position with inability to inject secondary to needle blockage confirmed with ultrasound. An expremature infant had initial needle placement anterior to the sacrum with subsequent proper placement using real-time ultrasound imaging. Ultrasound guidance for pediatric caudal placement confers advantages and increased routine use should be considered.

The N-Terminal Amphipathic Helix of the Topological Specificity Factor MinE Is Associated with Shaping Membrane Curvature

PubMed Central

Shih, Yu-Ling; Huang, Kai-Fa; Lai, Hsin-Mei; Liao, Jiahn-Haur; Lee, Chai-Siah; Chang, Chiao-Min; Mak, Huey-Ming; Hsieh, Cheng-Wei; Lin, Chu-Chi

2011-01-01

Pole-to-pole oscillations of the Min proteins in Escherichia coli are required for the proper placement of the division septum. Direct interaction of MinE with the cell membrane is critical for the dynamic behavior of the Min system. In vitro, this MinE-membrane interaction led to membrane deformation; however, the underlying mechanism remained unclear. Here we report that MinE-induced membrane deformation involves the formation of an amphipathic helix of MinE2–9, which, together with the adjacent basic residues, function as membrane anchors. Biochemical evidence suggested that the membrane association induces formation of the helix, with the helical face, consisting of A2, L3, and F6, inserted into the membrane. Insertion of this helix into the cell membrane can influence local membrane curvature and lead to drastic changes in membrane topology. Accordingly, MinE showed characteristic features of protein-induced membrane tubulation and lipid clustering in in vitro reconstituted systems. In conclusion, MinE shares common protein signatures with a group of membrane trafficking proteins in eukaryotic cells. These MinE signatures appear to affect membrane curvature. PMID:21738659

Clinical outcomes of an osteotome technique and simultaneous placement of Neoss implants in the posterior maxilla.

PubMed

Volpe, Stefano; Lanza, Massimiliano; Verrocchi, Damiano; Sennerby, Lars

2013-02-01

Insufficient bone volume often hamper placement of dental implants in the posterior maxilla. The aim of the present clinical study was to evaluate retrospectively the clinical outcome of implant placement in the resorbed posterior maxilla using an osteotome technique without adding any grafting material. Twenty patients with 5 to 9 mm of residual alveolar bone height in the posterior maxilla received twenty-nine implants (Neoss Ltd., Harrogate, UK) using an osteotomy technique without bone grafts. Intraoral radiographs were taken before and after implant placement, at the time of loading and after 11 to 32 months of loading (mean 16.4 months), to evaluate bone formation below the sinus membrane and marginal bone loss. Implant stability measurements (Osstell(TM) , Gothenburg, Sweden) were performed after implant installation and at abutment connection 5 months later. All implants were installed with the prosthetic platform level with the bone crest. No implant was lost giving a survival rate of 100% after a mean follow-up time of 16.4 months. The average vertical bone height was 7.2 ± 1.5 mm at placement and 10.0 ± 1.0 mm after 11 to 32 months. The average increase of 2.8 ± 1.1 mm was statistically significant. There was a statistically significant improvement in implant stability from 70.7 ± 9.2 implant stability quotient (ISQ) at placement to 76.7 ± 5.7 ISQ at abutment connection, 5 months later. The mean marginal bone loss amounted to 0.7 ± 0.3 mm after 11 to 32 months of loading. It is concluded that the osteotome technique evaluated resulted in predictable intrasinus bone formation, firm implant stability, and good clinical outcomes as no implants were lost and minimal marginal bone loss was observed. © 2011 Wiley Periodicals, Inc.

Comparative study of navigated versus freehand osteochondral graft transplantation of the knee.

PubMed

Koulalis, Dimitrios; Di Benedetto, Paolo; Citak, Mustafa; O'Loughlin, Padhraig; Pearle, Andrew D; Kendoff, Daniel O

2009-04-01

Osteochondral lesions are a common sports-related injury for which osteochondral grafting, including mosaicplasty, is an established treatment. Computer navigation has been gaining popularity in orthopaedic surgery to improve accuracy and precision. Navigation improves angle and depth matching during harvest and placement of osteochondral grafts compared with conventional freehand open technique. Controlled laboratory study. Three cadaveric knees were used. Reference markers were attached to the femur, tibia, and donor/recipient site guides. Fifteen osteochondral grafts were harvested and inserted into recipient sites with computer navigation, and 15 similar grafts were inserted freehand. The angles of graft removal and placement as well as surface congruity (graft depth) were calculated for each surgical group. The mean harvesting angle at the donor site using navigation was 4 degrees (standard deviation, 2.3 degrees ; range, 1 degrees -9 degrees ) versus 12 degrees (standard deviation, 5.5 degrees ; range, 5 degrees -24 degrees ) using freehand technique (P < .0001). The recipient plug removal angle using the navigated technique was 3.3 degrees (standard deviation, 2.1 degrees ; range, 0 degrees -9 degrees ) versus 10.7 degrees (standard deviation, 4.9 degrees ; range, 2 degrees -17 degrees ) in freehand (P < .0001). The mean navigated recipient plug placement angle was 3.6 degrees (standard deviation, 2.0 degrees ; range, 1 degrees -9 degrees ) versus 10.6 degrees (standard deviation, 4.4 degrees ; range, 3 degrees -17 degrees ) with freehand technique (P = .0001). The mean height of plug protrusion under navigation was 0.3 mm (standard deviation, 0.2 mm; range, 0-0.6 mm) versus 0.5 mm (standard deviation, 0.3 mm; range, 0.2-1.1 mm) using a freehand technique (P = .0034). Significantly greater accuracy and precision were observed in harvesting and placement of the osteochondral grafts in the navigated procedures. Clinical studies are needed to establish a benefit in vivo. Improvement in the osteochondral harvest and placement is desirable to optimize clinical outcomes. Navigation shows great potential to improve both harvest and placement precision and accuracy, thus optimizing ultimate surface congruity.

Speed synchronization control for integrated automotive motor-transmission powertrain system with random delays

NASA Astrophysics Data System (ADS)

Zhu, Xiaoyuan; Zhang, Hui; Fang, Zongde

2015-12-01

This paper presents a robust speed synchronization controller design for an integrated motor-transmission powertrain system in which the driving motor and multi-gearbox are directly coupled. As the controller area network (CAN) is commonly used in the vehicle powertrain system, the possible network-induced random delays in both feedback and forward channel are considered and modeled by using two Markov chains in the controller design process. For the application perspective, the control law adopted here is a generalized proportional-integral (PI) control. By employing the system-augmentation technique, a delay-free stochastic closed-loop system is obtained and the generalized PI controller design problem is converted to a static output feedback (SOF) controller design problem. Since there are external disturbances involved in the closed-loop system, the energy-to-peak performance is considered to guarantee the robustness of the controller. And the controlled output is chosen as the speed synchronization error. To further improve the transient response of the closed-loop system, the pole placement is also employed in the energy-to-peak performance based speed synchronization control. The mode-dependent control gains are obtained by using an iterative linear matrix inequality (LMI) algorithm. Simulation results show the effectiveness of the proposed control approach.

Adaptive control for solar energy based DC microgrid system development

NASA Astrophysics Data System (ADS)

Zhang, Qinhao

During the upgrading of current electric power grid, it is expected to develop smarter, more robust and more reliable power systems integrated with distributed generations. To realize these objectives, traditional control techniques are no longer effective in either stabilizing systems or delivering optimal and robust performances. Therefore, development of advanced control methods has received increasing attention in power engineering. This work addresses two specific problems in the control of solar panel based microgrid systems. First, a new control scheme is proposed for the microgrid systems to achieve optimal energy conversion ratio in the solar panels. The control system can optimize the efficiency of the maximum power point tracking (MPPT) algorithm by implementing two layers of adaptive control. Such a hierarchical control architecture has greatly improved the system performance, which is validated through both mathematical analysis and computer simulation. Second, in the development of the microgrid transmission system, the issues related to the tele-communication delay and constant power load (CPL)'s negative incremental impedance are investigated. A reference model based method is proposed for pole and zero placements that address the challenges of the time delay and CPL in closed-loop control. The effectiveness of the proposed modeling and control design methods are demonstrated in a simulation testbed. Practical aspects of the proposed methods for general microgrid systems are also discussed.

Minimizing Alteration of Posterior Tibial Slope During Opening Wedge High Tibial Osteotomy: a Protocol with Experimental Validation in Paired Cadaveric Knees

PubMed Central

Westermann, Robert W; DeBerardino, Thomas; Amendola, Annunziato

2014-01-01

Introduction The High Tibial Osteotomy (HTO) is a reliable procedure in addressing uni- compartmental arthritis with associated coronal deformities. With osteotomy of the proximal tibia, there is a risk of altering the tibial slope in the sagittal plane. Surgical techniques continue to evolve with trends towards procedure reproducibility and simplification. We evaluated a modification of the Arthrex iBalance technique in 18 paired cadaveric knees with the goals of maintaining sagittal slope, increasing procedure efficiency, and decreasing use of intraoperative fluoroscopy. Methods Nine paired cadaveric knees (18 legs) underwent iBalance medial opening wedge high tibial osteotomies. In each pair, the right knee underwent an HTO using the modified technique, while all left knees underwent the traditional technique. Independent observers evaluated postoperative factors including tibial slope, placement of hinge pin, and implant placement. Specimens were then dissected to evaluate for any gross muscle, nerve or vessel injury. Results Changes to posterior tibial slope were similar using each technique. The change in slope in traditional iBalance technique was -0.3° ±2.3° and change in tibial slope using the modified iBalance technique was -0.4° ±2.3° (p=0.29). Furthermore, we detected no differences in posterior tibial slope between preoperative and postoperative specimens (p=0.74 traditional, p=0.75 modified). No differences in implant placement were detected between traditional and modified techniques. (p=0.85). No intraoperative iatrogenic complications (i.e. lateral cortex fracture, blood vessel or nerve injury) were observed in either group after gross dissection. Discussion & Conclusions Alterations in posterior tibial slope are associated with HTOs. Both traditional and modified iBalance techniques appear reliable in coronal plane corrections without changing posterior tibial slope. The present modification of the Arthrex iBalance technique may increase the efficiency of the operation and decrease radiation exposure to patients without compromising implant placement or global knee alignment. PMID:25328454

A Matrix Pencil Algorithm Based Multiband Iterative Fusion Imaging Method

NASA Astrophysics Data System (ADS)

Zou, Yong Qiang; Gao, Xun Zhang; Li, Xiang; Liu, Yong Xiang

2016-01-01

Multiband signal fusion technique is a practicable and efficient way to improve the range resolution of ISAR image. The classical fusion method estimates the poles of each subband signal by the root-MUSIC method, and some good results were get in several experiments. However, this method is fragile in noise for the proper poles could not easy to get in low signal to noise ratio (SNR). In order to eliminate the influence of noise, this paper propose a matrix pencil algorithm based method to estimate the multiband signal poles. And to deal with mutual incoherent between subband signals, the incoherent parameters (ICP) are predicted through the relation of corresponding poles of each subband. Then, an iterative algorithm which aimed to minimize the 2-norm of signal difference is introduced to reduce signal fusion error. Applications to simulate dada verify that the proposed method get better fusion results at low SNR.

A Matrix Pencil Algorithm Based Multiband Iterative Fusion Imaging Method

PubMed Central

Zou, Yong Qiang; Gao, Xun Zhang; Li, Xiang; Liu, Yong Xiang

2016-01-01

Multiband signal fusion technique is a practicable and efficient way to improve the range resolution of ISAR image. The classical fusion method estimates the poles of each subband signal by the root-MUSIC method, and some good results were get in several experiments. However, this method is fragile in noise for the proper poles could not easy to get in low signal to noise ratio (SNR). In order to eliminate the influence of noise, this paper propose a matrix pencil algorithm based method to estimate the multiband signal poles. And to deal with mutual incoherent between subband signals, the incoherent parameters (ICP) are predicted through the relation of corresponding poles of each subband. Then, an iterative algorithm which aimed to minimize the 2-norm of signal difference is introduced to reduce signal fusion error. Applications to simulate dada verify that the proposed method get better fusion results at low SNR. PMID:26781194

Vertical Skin Paddle Orientation for the Latissimus Dorsi Flap in Breast Reconstruction: A Modification to Simultaneously Correct Inferior Pole Constriction and Improve Projection.

PubMed

Fracol, Megan; Grim, Michelle; Lanier, Steven T; Fine, Neil A

2018-03-01

The latissimus dorsi myocutaneous flap is a reliable and frequently used option to bring vascularized skin and soft tissue to improve the stability and aesthetic result in breast reconstruction. Standard techniques with skin paddle inset in a horizontal or oblique fashion preferentially improve anterior projection (when inset at the mastectomy scar) or lower pole and inframammary fold constriction (when inset into the inframammary fold). Here, the authors describe a modification for inset of the latissimus dorsi myocutaneous flap that improves both anterior projection and lower pole/inframammary fold constriction, and also allows the latissimus muscle to fan out and provide complete implant coverage. The vertical inset modification brings new skin and soft tissue into both the inferior pole and the central mastectomy scar, allowing simultaneous improvement in both areas and full use of the latissimus muscle to cover the implant or expander. Therapeutic, IV.

Review of evolution of tunnel position in anterior cruciate ligament reconstruction.

PubMed

Rayan, Faizal; Nanjayan, Shashi Kumar; Quah, Conal; Ramoutar, Darryl; Konan, Sujith; Haddad, Fares S

2015-03-18

Anterior cruciate ligament (ACL) rupture is one of the commonest knee sport injuries. The annual incidence of the ACL injury is between 100000-200000 in the United States. Worldwide around 400000 ACL reconstructions are performed in a year. The goal of ACL reconstruction is to restore the normal knee anatomy and kinesiology. The tibial and femoral tunnel placements are of primordial importance in achieving this outcome. Other factors that influence successful reconstruction are types of grafts, surgical techniques and rehabilitation programmes. A comprehensive understanding of ACL anatomy has led to the development of newer techniques supplemented by more robust biological and mechanical concepts. In this review we are mainly focussing on the evolution of tunnel placement in ACL reconstruction, focusing on three main categories, i.e., anatomical, biological and clinical outcomes. The importance of tunnel placement in the success of ACL reconstruction is well researched. Definite clinical and functional data is lacking to establish the superiority of the single or double bundle reconstruction technique. While there is a trend towards the use of anteromedial portals for femoral tunnel placement, their clinical superiority over trans-tibial tunnels is yet to be established.

Review of evolution of tunnel position in anterior cruciate ligament reconstruction

PubMed Central

Rayan, Faizal; Nanjayan, Shashi Kumar; Quah, Conal; Ramoutar, Darryl; Konan, Sujith; Haddad, Fares S

2015-01-01

Anterior cruciate ligament (ACL) rupture is one of the commonest knee sport injuries. The annual incidence of the ACL injury is between 100000-200000 in the United States. Worldwide around 400000 ACL reconstructions are performed in a year. The goal of ACL reconstruction is to restore the normal knee anatomy and kinesiology. The tibial and femoral tunnel placements are of primordial importance in achieving this outcome. Other factors that influence successful reconstruction are types of grafts, surgical techniques and rehabilitation programmes. A comprehensive understanding of ACL anatomy has led to the development of newer techniques supplemented by more robust biological and mechanical concepts. In this review we are mainly focussing on the evolution of tunnel placement in ACL reconstruction, focusing on three main categories, i.e., anatomical, biological and clinical outcomes. The importance of tunnel placement in the success of ACL reconstruction is well researched. Definite clinical and functional data is lacking to establish the superiority of the single or double bundle reconstruction technique. While there is a trend towards the use of anteromedial portals for femoral tunnel placement, their clinical superiority over trans-tibial tunnels is yet to be established. PMID:25793165

Biomechanical Strength of Retrograde Fixation in Proximal Third Scaphoid Fractures.

PubMed

Daly, Charles A; Boden, Allison L; Hutton, William C; Gottschalk, Michael B

2018-04-01

Current techniques for fixation of proximal pole scaphoid fractures utilize antegrade fixation via a dorsal approach endangering the delicate vascular supply of the dorsal scaphoid. Volar and dorsal approaches demonstrate equivalent clinical outcomes in scaphoid wrist fractures, but no study has evaluated the biomechanical strength for fractures of the proximal pole. This study compares biomechanical strength of antegrade and retrograde fixation for fractures of the proximal pole of the scaphoid. A simulated proximal pole scaphoid fracture was produced in 22 matched cadaveric scaphoids, which were then assigned randomly to either antegrade or retrograde fixation with a cannulated headless compression screw. Cyclic loading and load to failure testing were performed and screw length, number of cycles, and maximum load sustained were recorded. There were no significant differences in average screw length (25.5 mm vs 25.6 mm, P = .934), average number of cyclic loading cycles (3738 vs 3847, P = .552), average load to failure (348 N vs 371 N, P = .357), and number of catastrophic failures observed between the antegrade and retrograde fixation groups (3 in each). Practical equivalence between the 2 groups was calculated and the 2 groups were demonstrated to be practically equivalent (upper threshold P = .010). For this model of proximal pole scaphoid wrist fractures, antegrade and retrograde screw configuration have been proven to be equivalent in terms of biomechanical strength. With further clinical study, we hope surgeons will be able to make their decision for fixation technique based on approaches to bone grafting, concern for tenuous blood supply, and surgeon preference without fear of poor biomechanical properties.

Importance of double-pole CFS-PML for broad-band seismic wave simulation and optimal parameters selection

NASA Astrophysics Data System (ADS)

Feng, Haike; Zhang, Wei; Zhang, Jie; Chen, Xiaofei

2017-05-01

The perfectly matched layer (PML) is an efficient absorbing technique for numerical wave simulation. The complex frequency-shifted PML (CFS-PML) introduces two additional parameters in the stretching function to make the absorption frequency dependent. This can help to suppress converted evanescent waves from near grazing incident waves, but does not efficiently absorb low-frequency waves below the cut-off frequency. To absorb both the evanescent wave and the low-frequency wave, the double-pole CFS-PML having two poles in the coordinate stretching function was developed in computational electromagnetism. Several studies have investigated the performance of the double-pole CFS-PML for seismic wave simulations in the case of a narrowband seismic wavelet and did not find significant difference comparing to the CFS-PML. Another difficulty to apply the double-pole CFS-PML for real problems is that a practical strategy to set optimal parameter values has not been established. In this work, we study the performance of the double-pole CFS-PML for broad-band seismic wave simulation. We find that when the maximum to minimum frequency ratio is larger than 16, the CFS-PML will either fail to suppress the converted evanescent waves for grazing incident waves, or produce visible low-frequency reflection, depending on the value of α. In contrast, the double-pole CFS-PML can simultaneously suppress the converted evanescent waves and avoid low-frequency reflections with proper parameter values. We analyse the different roles of the double-pole CFS-PML parameters and propose optimal selections of these parameters. Numerical tests show that the double-pole CFS-PML with the optimal parameters can generate satisfactory results for broad-band seismic wave simulations.

Development of a neurofeedback protocol targeting the frontal pole using near-infrared spectroscopy.

PubMed

Kinoshita, Akihide; Takizawa, Ryu; Yahata, Noriaki; Homae, Fumitaka; Hashimoto, Ryuichiro; Sakakibara, Eisuke; Kawasaki, Shingo; Nishimura, Yukika; Koike, Shinsuke; Kasai, Kiyoto

2016-11-01

Neurofeedback has been studied with the aim of controlling cerebral activity. Near-infrared spectroscopy is a non-invasive neuroimaging technique used for measuring hemoglobin concentration changes in cortical surface areas with high temporal resolution. Thus, near-infrared spectroscopy may be useful for neurofeedback, which requires real-time feedback of repeated brain activation measurements. However, no study has specifically targeted neurofeedback, using near-infrared spectroscopy, in the frontal pole cortex. We developed an original near-infrared spectroscopy neurofeedback system targeting the frontal pole cortex. Over a single day of testing, each healthy participant (n = 24) received either correct or incorrect (Sham) feedback from near-infrared spectroscopy signals, based on a crossover design. Under correct feedback conditions, significant activation was observed in the frontal pole cortex (P = 0.000073). Additionally, self-evaluation of control and metacognitive beliefs were associated with near-infrared spectroscopy signals (P = 0.006). The neurofeedback system developed in this study might be useful for developing control of frontal pole cortex activation. © 2016 The Authors. Psychiatry and Clinical Neurosciences © 2016 Japanese Society of Psychiatry and Neurology.

Transitioning from anatomic landmarks to ultrasound guided central venous catheterizations: guidelines applied to clinical practice.

PubMed

Oom, Rodrigo; Casaca, Rui; Barroca, Rita; Carvalhal, Sara; Santos, Catarina; Abecasis, Nuno

2017-07-14

Centrally inserted central catheter (CICC) insertion is a commonly performed procedure that may give rise to different complications. Despite the suggestion of guidelines to use ultrasound guidance (USG) for vascular access, not all centers use it systematically. The aim of this study is to illustrate the experience with ultrasound in CICC placement at a high-volume oncological center, in a country where the landmark technique is standard. Retrospective analysis of a prospective database was performed on CICC placement under USG in the Central Venous Catheter Unit of Instituto Português de Oncologia de Lisboa Francisco Gentil, from 2012 to 2015. Three thousand five hundred and seventy-two procedures were recorded. From 2728 CICC placements, 1187 (43.5%) were done using USG. The majority of CICC placements were successful without immediate complications (96.1%). In 55 cases (4.6%), more than three attempts were necessary to puncture the vein. Pneumothorax occurred in 5 cases (0.4%) and arterial puncture was registered in 41 cases (3.5%). An increasing use of USG for placing CICCs was planned and observed over the years and, in the last year of the study, 67.3% of the CICC placements were with USG. CICC placement with USG is a safe and effective technique. Despite some resistance that is observed, these results support that it is worth following the guidelines that advocate the use of the USG in the placement of CICC.

Sizing up Asteroids at Lick Observatory with Adaptive Optics

NASA Astrophysics Data System (ADS)

Drummond, Jack D.; Christou, J.

2006-12-01

Using the Shane 3 meter telescope with adaptive optics at Lick Observatory, we have determined the triaxial dimensions and rotational poles of five asteroids, 3 Juno, 4 Vesta, 16 Psyche, 87 Sylvia, and 324 Bamberga. Parametric blind deconvolution was applied to images obtained mostly at 2.5 microns in 2004 and 2006. This is the first time Bamberga’s pole has been determined, and the results for the other four asteroids are in agreement with the analysis of decades of lightcurves by others. The techniques developed here to find sizes, shapes, and poles, in only one or two nights, can be applied to smaller asteroids that are resolved with larger telescopes.

Ultrasound-guided venous access for pacemakers and defibrillators.

PubMed

Seto, Arnold H; Jolly, Aaron; Salcedo, Jonathan

2013-03-01

Ultrasound guidance is widely recommended to reduce the risk of complications during central venous catheter placement. However, ultrasound guidance is not commonly utilized for implanting leads for cardiac rhythm management devices. We describe our technique of ultrasound-guided pacemaker implantation, including a novel pull-through technique that allows percutaneous guidewire insertion prior to the first incision. We review the literature and recent advances in ultrasound imaging technology that may facilitate the adoption of ultrasound guidance. Ultrasound guidance provides a safe and rapid technique for extrathoracic subclavian or axillary venous lead placement. © 2012 Wiley Periodicals, Inc.

A comparison of Espocan and Tuohy needles for the combined spinal-epidural technique for labor analgesia.

PubMed

Browne, Ingrid M; Birnbach, David J; Stein, Deborah J; O'Gorman, David A; Kuroda, Maxine

2005-08-01

When using the needle-through-needle combined spinal-epidural (CSE) technique for labor analgesia, failure to obtain cerebrospinal fluid (CSF), paresthesias, and intrathecal or intravascular migration of the catheter are of concern. Epidural needles with spinal needle apertures, such as the back-hole Espocan (ES) needles, are available and may reduce these risks. We describe the efficacy and adverse events associated with a modified epidural needle (ES) versus a conventional Tuohy needle for CSE. One-hundred parturients requesting labor analgesia (CSE) were randomized into 2 groups: 50-ES 18-gauge modified epidural needle with 27-gauge Pencan atraumatic spinal needle, 50-conventional 18-gauge Tuohy needle with 27-gauge Gertie Marx atraumatic spinal needle. Information on intrathecal or intravascular catheter placement, paresthesia on introduction of spinal needle, failure to obtain CSF through the spinal needle after placement of epidural needle, unintentional dural puncture, and epidural catheter function was obtained. No intrathecal catheter placement occurred in either group. Rates of intravascular catheter placement and unintentional dural puncture were similar between the groups. Significant differences were noted regarding spinal needle-induced paresthesia (14% ES versus 42% Tuohy needles, P = 0.009) and failure to obtain CSF on first attempt (8% ES versus 28% Tuohy needles, P < 0.02). Use of ES needles for CSE significantly reduces paresthesia associated with the insertion of the spinal needle and is associated with more frequent successful spinal needle placement on the first attempt. The use of modified epidural needles with a back hole for combined spinal-epidural technique significantly reduces paresthesia associated with the insertion of the spinal needle and is associated with more frequent successful spinal needle placement on the first attempt.

Frequency doubling in poled polymers using anomalous dispersion phase-matching

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

Kowalczyk, T.C.; Singer, K.D.; Cahill, P.A.

1995-10-01

The authors report on a second harmonic generation in a poled polymer waveguide using anomalous dispersion phase-matching. Blue light ({lambda} = 407 nm) was produced by phase-matching the lowest order fundamental and harmonic modes over a distance of 32 {micro}m. The experimental conversion efficiency was {eta} = 1.2 {times} 10{sup {minus}4}, in agreement with theory. Additionally, they discuss a method of enhancing the conversion efficiency for second harmonic generation using anomalous dispersion phase-matching to optimize Cerenkov second harmonic generation. The modeling shows that a combination of phase-matching techniques creates larger conversion efficiencies and reduces critical fabrication requirements of the individualmore » phase-matching techniques.« less

Fluoroscopic Placement of Double-Pigtail Ureteral Stents

PubMed Central

Chen, Gregory L.

2001-01-01

Purpose: Double-pigtail ureteral stent is placed cystoscopically after ureteroscopy. We describe a technique for fluoroscopic placement of ureteral stents and demonstrate its use in a non-randomized prospective study. Materials and methods: Double-pigtail stents were placed either fluoroscopically or cystoscopically in 121 consecutive patients. In the fluoroscopic method, the stent was placed over a guide wire using a stent pusher without the use of cystoscopy. Conversely, stents were placed through the working channel of the cystoscope under vision. The procedure, stent length, width, type, method, ureteral dilation, and use of a retrieval string were noted. Results: A wide range of stent sizes were used. The success with fluoroscopic placement of double-pigtail ureteral stents was 100% (89 of 89 cases). No stents migrated or required replacement. Stents were placed after ureteroscopic laser lithotripsy (53/89) and ureteroscopic tumor treatment (22/89). Cystoscopic visualization was used in 32 additional procedures requiring precise control (15 ureteral strictures and nine retrograde endopyelotomy). Conclusions: The fluoroscopic placement of ureteral stents is a safe and simple technique with a very high success rate. We have used cystoscopic placement only after incisional procedures such as retrograde endopyelotomy, stricture or ureterotomy. PMID:18493562

Botulinum toxin type A injection into the gastrocnemius muscle for spastic equinus in adults with stroke: a randomized controlled trial comparing manual needle placement, electrical stimulation and ultrasonography-guided injection techniques.

PubMed

Picelli, Alessandro; Tamburin, Stefano; Bonetti, Paola; Fontana, Carla; Barausse, Martina; Dambruoso, Francesca; Gajofatto, Francesca; Santilli, Valter; Smania, Nicola

2012-11-01

The aim of this study was to compare the clinical outcomes of manual needle placement, electrical stimulation, and ultrasonography-guided techniques for botulinum toxin injection into the gastrocnemius of adults with spastic equinus after stroke. After randomization into three groups, each patient received the same dose of botulinum toxin type A into the lateral and medial head of the gastrocnemius muscle (OnabotulinumtoxinA, 100U per head) of the affected leg. The manual needle placement group (n = 15) underwent injections using anatomic landmarks and palpation; the electrical stimulation group (n = 15) received injections with electrical stimulation guidance; and the ultrasonography group (n = 17) was injected under sonographic guidance. The modified Ashworth scale, the Tardieu scale, and the ankle passive range of motion were measured at baseline and 1 mo after injection. Nonparametric statistical analysis was used. One month after injection, the modified Ashworth scale improved better in the ultrasonography group than in the manual needle placement group (P = 0.008). The ankle passive range of motion improved better in the ultrasonography group than in the electrical stimulation (P = 0.004) and manual needle placement (P < 0.001) groups. No difference was found between groups for the Tardieu scale. Ultrasonography-guided injection technique could improve the clinical outcome of botulinum toxin injections into the gastrocnemius of adults with spastic equinus.

Does intraoperative navigation improve the accuracy of pedicle screw placement in the apical region of dystrophic scoliosis secondary to neurofibromatosis type I: comparison between O-arm navigation and free-hand technique.

PubMed

Jin, Mengran; Liu, Zhen; Liu, Xingyong; Yan, Huang; Han, Xiao; Qiu, Yong; Zhu, Zezhang

2016-06-01

To assess the accuracy of O-arm-navigation-based pedicle screw insertion in dystrophic scoliosis secondary to NF-1 and compare it with free-hand pedicle screw insertion technique. 32 patients with dystrophic NF-1-associated scoliosis were divided into two groups. A total of 92 pedicle screws were implanted in apical region (two vertebrae above and below the apex each) in 13 patients using O-arm-based navigation (O-arm group), and 121 screws were implanted in 19 patients using free-hand technique (free-hand group). The postoperative CT images were reviewed and analyzed for pedicle violation. The screw penetration was divided into four grades: grade 0 (ideal placement), grade 1 (penetration <2 mm), grade 2 (penetration between 2 and 4 mm), and grade 3 (penetration >4 mm). The accuracy rate of pedicle screw placement (grade 0, 1) was significantly higher in the O-arm group (79 %, 73/92) compared to 67 % (81/121) of the free-hand group (P = 0.045). Meanwhile, a significantly lower prevalence of grade 2-3 perforation was observed in the O-arm group (21 vs. 33 %, P < 0.05), and the incidence of medial perforation was significantly minimized by using O-arm navigation compared to free-hand technique (2 vs. 15 %, P < 0.01). Moreover, the implant density in apical region was significantly elevated by using O-arm navigation (58 vs. 42 %, P < 0.001). We reported 79 % accuracy of O-arm-based pedicle screw placement in dystrophic NF-1-associated scoliosis. O-arm navigation system does facilitate pedicle screw insertion in dystrophic NF-1-associated scoliosis, demonstrating superiorities in the safety and accuracy of pedicle screw placement in comparison with free-hand technique.

JND measurements of the speech formants parameters and its implication in the LPC pole quantization

NASA Astrophysics Data System (ADS)

Orgad, Yaakov

1988-08-01

The inherent sensitivity of auditory perception is explicitly used with the objective of designing an efficient speech encoder. Speech can be modelled by a filter representing the vocal tract shape that is driven by an excitation signal representing glottal air flow. This work concentrates on the filter encoding problem, assuming that excitation signal encoding is optimal. Linear predictive coding (LPC) techniques were used to model a short speech segment by an all-pole filter; each pole was directly related to the speech formants. Measurements were made of the auditory just noticeable difference (JND) corresponding to the natural speech formants, with the LPC filter poles as the best candidates to represent the speech spectral envelope. The JND is the maximum precision required in speech quantization; it was defined on the basis of the shift of one pole parameter of a single frame of a speech segment, necessary to induce subjective perception of the distortion, with .75 probability. The average JND in LPC filter poles in natural speech was found to increase with increasing pole bandwidth and, to a lesser extent, frequency. The JND measurements showed a large spread of the residuals around the average values, indicating that inter-formant coupling and, perhaps, other, not yet fully understood, factors were not taken into account at this stage of the research. A future treatment should consider these factors. The average JNDs obtained in this work were used to design pole quantization tables for speech coding and provided a better bit-rate than the standard quantizer of reflection coefficient; a 30-bits-per-frame pole quantizer yielded a speech quality similar to that obtained with a standard 41-bits-per-frame reflection coefficient quantizer. Owing to the complexity of the numerical root extraction system, the practical implementation of the pole quantization approach remains to be proved.

Silicone Y-Stent Placement on the Secondary Left Carina.

PubMed

Oki, Masahide; Saka, Hideo

2015-01-01

The silicone Y-stent has mainly been used for the treatment of lesions around the main carina, and only a few case reports have been published on the technique for the lesions around the secondary left carina (LC2). We investigated the feasibility, efficacy and safety of a stenting technique using a silicone Y-stent for patients with airway stenosis around LC2. Patients who underwent airway stent placement between December 2010 and September 2014 in a single center were retrospectively reviewed. Under general anesthesia, using rigid and flexible bronchoscopes, the airway lumen was re-established followed by Y-stent placement on LC2. We performed 274 airway stenting procedures for 253 patients during the study period. Twelve of them (7 with lung cancer, 3 with esophageal cancer/carcinosarcoma, 1 with thyroid cancer and 1 with renal cancer) underwent a Y-stent placement on LC2. Respiratory symptoms were relieved in all patients. Six of 7 patients with supplemental oxygen, including the mechanically ventilated patient before stent placement, could be discharged without supplemental oxygen. The chest radiograph after the procedure showed increased lung volume in all 7 patients with partial or complete atelectasis. Median survival after stenting was 197 days at the time of data collection. Retention of secretions occurred in 1 and hemoptysis in another patient. Silicone Y-stent placement on LC2 is technically feasible, effective and acceptably safe. © 2015 S. Karger AG, Basel.

Management of lower pole renal stones: the devil is in the details.

PubMed

Resorlu, Berkan; Issi, Yasar; Onem, Kadir; Germiyanoglu, Cankon

2016-03-01

Shock wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS) and minimally invasive percutaneous nephrolithotomy (MIP) are highly effective treatment options for lower pole stones up to 2 cm. Selecting the best treatment modality represents a controversial area in urology, because each treatment methods have their own advantages and disadvantages. Donaldson and co-workers have recently published a very comprehensive review and meta-analysis to compare the benefits and harms of SWL, RIRS and PNL techniques.

NASA satellite to track North Pole expedition

NASA Technical Reports Server (NTRS)

1978-01-01

The proposed expedition of a lone explorer and the use of Nimbus 6 (NASA meteorological research satellite) to track his journey is reported. The journey is scheduled to start March 4, 1978, and will cover a distance of 6.000 Km (3,728 miles) from northern Canada to the North Pole and return, traveling the length of Greenland's isolated interior. The mode of transportation for the explorer will be by dog sled. Instrumentation and tracking techniques are discussed.

Static magnetic field effects on the sagittal suture in Rattus norvegicus.

PubMed

Camilleri, S; McDonald, F

1993-03-01

Twenty-day-old Wistar albino rats were exposed to static magnetic fields by placing a neodymium-iron-boron magnetic over their sagittal suture. Cellular activity was monitored by the uptake of tritiated thymidine in control, north, south, and unoperated animals at 1, 3, 5, and 10 days (n = 10 per group). A total of 160 animals were used for this part of the study, with the animals examined 1, 3, 5, and 10 days after surgery. Bone remodeling was examined by tetracycline fluorescence with 10 animals allocated to 5- and 10-day periods for north and south poles (n = 10 per group) and control experiments. This consisted of the placement of unmagnetized alloy, similar in size and shape to the magnets, and also included unoperated animals (n = 5 per group). A total of 60 animals were used for the tetracycline study and were examined at 5 and 10 days after surgery. While the tetracycline examination revealed very little change, the thymidine reflected a reduction in thymidine uptake subsequent to placement of the magnet, reaching a maximal effect at 3 days and returning to a normal value thereafter. This questions the potential of static magnetic fields affecting cell mitotic activity as previously reported.

Academic achievement and course taking among language minority youth in U.S. schools: Effects of ESL placement

PubMed Central

Callahan, Rebecca; Wilkinson, Lindsey; Muller, Chandra

2014-01-01

The 1974 Lau decision requires that U.S. public schools ensure a meaningful education for students learning English. English as a Second Language (ESL) placement is an institutional response to the linguistic needs of these students; however, its academic implications remain largely unexplored. Using nationally representative data from the Educational Longitudinal Study (ELS), the effects of ESL placement on college preparatory course enrollment and academic achievement of language minority students are estimated, first with fixed effects regression models and then with multi-level propensity score matching techniques. While numerous school and individual level factors beyond language proficiency predict ESL placement, a significant negative estimated effect of ESL placement on science enrollment and cumulative GPA is consistently found. Perhaps more important, however, no positive effects of ESL placement on the achievement of language minority youth are found when accounting for English proficiency and other potential covariates. PMID:25431506

Academic achievement and course taking among language minority youth in U.S. schools: Effects of ESL placement.

PubMed

Callahan, Rebecca; Wilkinson, Lindsey; Muller, Chandra

2010-03-01

The 1974 Lau decision requires that U.S. public schools ensure a meaningful education for students learning English. English as a Second Language (ESL) placement is an institutional response to the linguistic needs of these students; however, its academic implications remain largely unexplored. Using nationally representative data from the Educational Longitudinal Study (ELS), the effects of ESL placement on college preparatory course enrollment and academic achievement of language minority students are estimated, first with fixed effects regression models and then with multi-level propensity score matching techniques. While numerous school and individual level factors beyond language proficiency predict ESL placement, a significant negative estimated effect of ESL placement on science enrollment and cumulative GPA is consistently found. Perhaps more important, however, no positive effects of ESL placement on the achievement of language minority youth are found when accounting for English proficiency and other potential covariates.

Dual Coverage of the Inferior Pole with Conjoined Fascial Flap and Acellular Dermal Matrix for Immediate One-Stage Breast Reconstruction with a Prosthetic Implant.

PubMed

Lee, Seo H; Chun, Yong S; Park, Heung K; Kim, Yang W; Cheon, Young W

2018-04-17

Elevation of a conjoined fascial flap composed of the pectoralis major, serratus anterior, and external oblique fascia is a type of surgical technique using autologous tissue to cover the lower pole after immediate one-stage direct-to-implant (DTI) breast reconstruction. However, volumetric breast implants hinder use of this technique alone. For better structural stability and more aesthetically favorable breast contour in large breasts, we have devised a technique involving dual coverage of the lower pole by a conjoined fascial flap and acellular dermal matrix (ADM). Twenty Asian patients underwent DTI breast reconstruction from March 2013 to May 2014. ADM was used to cover the inferomedial quadrant of the breast, and a conjoined fascial flap was elevated to cover the remaining inferolateral quadrant. Both patient- and plastic surgeon-reported outcome measures were assessed using questionnaires. For every domain of the patient- and plastic surgeon-reported questionnaires, the mean scores were between satisfied and very satisfied. Two patients developed a seroma and one patient developed partial skin flap necrosis. Both seromas resolved after a series of aspirations. The necrotic skin flap was revised under local anesthesia 3 weeks after the reconstructive surgery. The use of dual coverage of the inferior pole with a conjoined fascial flap and ADM for immediate DTI among patients with large breasts is supported by high scores in both patient- and plastic surgeon-reported outcome measures, as well as low complication rates. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Secondary Voice Restoration After Laryngotracheal Separation (LTS) for Dysphagia with Intractable Aspiration.

PubMed

Bonte, Katrien; Huvenne, Wouter; De Loof, Marie; Deron, Philippe; Viaene, Annick; Duprez, Fréderic; Vermeersch, Hubert

2015-12-01

Intractable aspiration is a serious, often life-threatening condition due to its potential impact on pulmonary function. Aspiration requires therapeutic measures, starting with conservative management but often necessitating surgical treatment. The basic surgical principle is to separate the alimentary and respiratory tracts through a variety of procedures which, unfortunately, nearly all result in the loss of phonation, with the exception of total laryngectomy (TL) which includes the placement of an indwelling voice prosthesis. In this study, we present a modified laryngotracheal separation (LTS) technique that, we believe, offers multiple advantages compared to standard TL. After reviewing the medical records of 35 patients with intractable aspiration who have undergone LTS, we describe the surgical technique and present the postoperative result. In a second surgical procedure about two months following LTS, we aimed to achieve voice restoration by placement of an indwelling voice prosthesis. Intractable aspiration was successfully treated in all patients. Placement of an indwelling voice prosthesis during a second operation was successful in 15 patients, representing the largest reported cohort thus far. LTS is a reliable surgical technique to treat intractable aspiration, with restoration of oral intake, thereby improving the general condition and quality of life of these unfortunate patients. Furthermore, voice restoration can be achieved in selected patients, by placement of a voice prosthesis.

SUSTAIN – A Framework for Placement of Best Management Practices in Urban Watersheds to Protect Water Quality

EPA Science Inventory

SUSTAIN (System for Urban Stormwater Treatment and Analysis INtegration) is a decision support system to facilitate selection and placement of best management practices (BMPs) and low impact development (LID) techniques at strategic locations in urban watersheds. It was develope...

20 CFR 670.730 - What are the responsibilities of placement agencies?

Code of Federal Regulations, 2010 CFR

2010-04-01

... LABOR THE JOB CORPS UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Placement and Continued Services § 670... techniques and job search strategies; (3) Identifying job leads or educational and training opportunities through coordination with local Workforce Investment Boards, One-Stop operators and partners, employers...

Immediate Implants: Clinical Guidelines for Esthetic Outcomes

PubMed Central

Javaid, Mohammad A.; Khurshid, Zohaib; Zafar, Muhammad S.; Najeeb, Shariq

2016-01-01

Research has shown that tooth loss results in morphological changes in alveolar ridge that may influence the subsequent implant placement. Immediate implant placement was introduced as a possible means to limit bone resorption and reduce the number of surgical procedures following tooth extraction. Histological and clinical evidence from human clinical studies showing efficacy of immediate implants has come to light over the last decade or so. However, immediate implant placement is a challenging surgical procedure and requires proper case selection and surgical technique. Furthermore, there appears to be a lack of clinical guidelines for immediate implant placement case selection. Therefore, the aim of this mini-review is to analyze critical evidence from human studies in order to establish clinical guidelines which may help clinicians in case selection when considering immediate implant placement protocol. PMID:29563463

Percutaneous Nephrostomy: Technical Aspects and Indications

PubMed Central

Dagli, Mandeep; Ramchandani, Parvati

2011-01-01

First described in 1955 by Goodwin et al as a minimally invasive treatment for urinary obstruction causing marked hydronephrosis, percutaneous nephrostomy (PCN) placement quickly found use in a wide variety of clinical indications in both dilated and nondilated systems. Although the advancement of modern endourological techniques has led to a decline in the indications for primary nephrostomy placement, PCNs still play an important role in the treatment of multiple urologic conditions. In this article, the indications, placement, and postprocedure management of percutaneous nephrostomy drainage are described. PMID:23204641

High-precision control of LSRM based X-Y table for industrial applications.

PubMed

Pan, J F; Cheung, Norbert C; Zou, Yu

2013-01-01

The design of an X-Y table applying direct-drive linear switched reluctance motor (LSRM) principle is proposed in this paper. The proposed X-Y table has the characteristics of low cost, simple and stable mechanical structure. After the design procedure is introduced, an adaptive position control method based on online parameter identification and pole-placement regulation scheme is developed for the X-Y table. Experimental results prove the feasibility and its priority over a traditional PID controller with better dynamic response, static performance and robustness to disturbances. It is expected that the novel two-dimensional direct-drive system find its applications in high-precision manufacture area. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Elegant anti-disturbance control for discrete-time stochastic systems with nonlinearity and multiple disturbances

NASA Astrophysics Data System (ADS)

Wei, Xinjiang; Sun, Shixiang

2018-03-01

An elegant anti-disturbance control (EADC) strategy for a class of discrete-time stochastic systems with both nonlinearity and multiple disturbances, which include the disturbance with partially known information and a sequence of random vectors, is proposed in this paper. A stochastic disturbance observer is constructed to estimate the disturbance with partially known information, based on which, an EADC scheme is proposed by combining pole placement and linear matrix inequality methods. It is proved that the two different disturbances can be rejected and attenuated, and the corresponding desired performances can be guaranteed for discrete-time stochastic systems with known and unknown nonlinear dynamics, respectively. Simulation examples are given to demonstrate the effectiveness of the proposed schemes compared with some existing results.

Decentralized control of large-scale systems: Fixed modes, sensitivity and parametric robustness. Ph.D. Thesis - Universite Paul Sabatier, 1985

NASA Technical Reports Server (NTRS)

Tarras, A.

1987-01-01

The problem of stabilization/pole placement under structural constraints of large scale linear systems is discussed. The existence of a solution to this problem is expressed in terms of fixed modes. The aim is to provide a bibliographic survey of the available results concerning the fixed modes (characterization, elimination, control structure selection to avoid them, control design in their absence) and to present the author's contribution to this problem which can be summarized by the use of the mode sensitivity concept to detect or to avoid them, the use of vibrational control to stabilize them, and the addition of parametric robustness considerations to design an optimal decentralized robust control.

Computational methods of robust controller design for aerodynamic flutter suppression

NASA Technical Reports Server (NTRS)

Anderson, L. R.

1981-01-01

The development of Riccati iteration, a tool for the design and analysis of linear control systems is examined. First, Riccati iteration is applied to the problem of pole placement and order reduction in two-time scale control systems. Order reduction, yielding a good approximation to the original system, is demonstrated using a 16th order linear model of a turbofan engine. Next, a numerical method for solving the Riccati equation is presented and demonstrated for a set of eighth order random examples. A literature review of robust controller design methods follows which includes a number of methods for reducing the trajectory and performance index sensitivity in linear regulators. Lastly, robust controller design for large parameter variations is discussed.

Precise computer controlled positioning of robot end effectors using force sensors

NASA Technical Reports Server (NTRS)

Shieh, L. S.; Mcinnis, B. C.; Wang, J. C.

1988-01-01

A thorough study of combined position/force control using sensory feedback for a one-dimensional manipulator model, which may count for the spacecraft docking problem or be extended to the multi-joint robot manipulator problem, was performed. The additional degree of freedom introduced by the compliant force sensor is included in the system dynamics in the design of precise position control. State feedback based on the pole placement method and with integral control is used to design the position controller. A simple constant gain force controller is used as an example to illustrate the dependence of the stability and steady-state accuracy of the overall position/force control upon the design of the inner position controller. Supportive simulation results are also provided.

Management of displaced inferior patellar pole fractures with modified tension band technique combined with cable cerclage using Cable Grip System.

PubMed

Yang, Xu; Wu, Qinfen; Lai, Chin-Hui; Wang, Xin

2017-10-01

We present a modified tension band technique combined with cable cerclage using Cable Grip System for the treatment of displaced inferior patellar pole fractures and report the knee functional outcome. The patients who had had operative treatment of a displaced inferior patellar pole fracture (AO/OTA 34-A1) between December 2013 and December 2015 were studied retrospectively. Eleven consecutive patients had had open reduction and internal fixation with the modified technique using Cable Grip System, of whom, five males and six females with an average age of 60.9 years (range, 29-81 years). All fractures occurred from direct fall onto the knee. The average time from injury to surgery was 6.1days (range, 2-12days). The range of motion (ROM) was measured in degrees by goniometry at postoperative intervals of 1, 2, 4, 12, and 48 weeks; Knee function was evaluated using the Rasmussen scores at final follow-up. No patients had nonunion, loss of reduction, migration of wire, irritation from the implant and fixation breakage during the follow-up period. Recovery of ROM was achieved at 12 weeks, with the average ROM at 1 week was 72° (range, 65°-78°), 86.4° (range, 78°-92°) at 2 weeks, 115.5° (range, 103°-122°) at 4 weeks, 129.6° (range, 122°-133°) at 12 weeks, 134.5° (range, 129°-139°) at 48 weeks after the operation. Concerning the knee function outcome assessment, all patients showed excellent results at final follow-up. The average Rasmussen scores was 27.9 out of 30 (range, 27-29). The modified tension band technique combined with cable cerclage using Cable Grip System for displaced inferior patellar pole fractures can provide stable fixation with excellent results in knee function, allows for immediate mobilization and early weight-bearing, which is a simple and valuable technique in routine clinical practice. Copyright © 2017 Elsevier Ltd. All rights reserved.

The blind pushing technique for peripherally inserted central catheter placement through brachial vein puncture.

PubMed

Lee, Jae Myeong; Cho, Young Kwon; Kim, Han Myun; Song, Myung Gyu; Song, Soon-Young; Yeon, Jae Woo; Yoon, Dae Young; Lee, Sam Yeol

2018-03-01

The objective of this study was to conduct a prospective clinical trial evaluating the technical feasibility and short-term clinical outcome of the blind pushing technique for placement of pretrimmed peripherally inserted central catheters (PICCs) through brachial vein access. Patients requiring PICC placement at any of the three participating institutions were prospectively enrolled between January and December 2016. The review boards of all participating institutions approved this study, and informed consent was obtained from all patients. PICC placement was performed using the blind pushing technique and primary brachial vein access. The following data were collected from unified case report forms: access vein, obstacles during PICC advancement, procedure time, and postprocedural complications. During the 12-month study period, 1380 PICCs were placed in 1043 patients. Of these, 1092 PICCs placed in 837 patients were enrolled, with 834 PICCs (76%) and 258 PICCs (34%) placed through brachial vein and nonbrachial vein access, respectively. In both arms, obstacles were most commonly noted in the subclavian veins (n = 220) and axillary veins (n = 94). Successful puncture of the access vein was achieved at first try in 1028 PICCs (94%). The technical success rate was 99%, with 1055 PICCs (97%) placed within 120 seconds of procedure time and 1088 PICCs (99%) having the tip located at the ideal position. Follow-up Doppler ultrasound detected catheter-associated upper extremity deep venous thrombosis (UEDVT) for 18 PICCs in 16 patients and late symptomatic UEDVT for 16 PICCs in 16 patients (3.1%). Catheter-associated UEDVT was noted for 28 PICCs (82%) and 6 PICCs (18%) placed through brachial vein and nonbrachial vein access, respectively. The incidence of obstacles and the procedure time (<120 seconds) differed significantly between brachial vein and nonbrachial vein access (P = .001). There was no statistically significant difference between brachial vein and nonbrachial vein access in the incidence of UEDVT (odds ratio, 0.68; 95% confidence interval, 0.59-3.52; P = .22). The placement of pretrimmed PICCs by the blind pushing technique and primary brachial vein access is technically feasible and may represent an alternative to the conventional PICC placement technique, having low incidences of UEDVT and other complications, with no significant difference in outcomes between brachial vein and nonbrachial vein access. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Design optimization for permanent magnet machine with efficient slot per pole ratio

NASA Astrophysics Data System (ADS)

Potnuru, Upendra Kumar; Rao, P. Mallikarjuna

2018-04-01

This paper presents a methodology for the enhancement of a Brush Less Direct Current motor (BLDC) with 6Poles and 8slots. In particular; it is focused on amulti-objective optimization using a Genetic Algorithmand Grey Wolf Optimization developed in MATLAB. The optimization aims to maximize the maximum output power value and minimize the total losses of a motor. This paper presents an application of the MATLAB optimization algorithms to brushless DC (BLDC) motor design, with 7 design parameters chosen to be free. The optimal design parameters of the motor derived by GA are compared with those obtained by Grey Wolf Optimization technique. A comparative report on the specified enhancement approaches appearsthat Grey Wolf Optimization technique has a better convergence.

Effect of poling process on piezoelectric properties of BCZT - 0.08 wt.% CeO{sub 2} lead-free ceramics

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

Chandrakala, E.; Praveen, J. Paul; Das, Dibakar, E-mail: ddse@uohyd.ernet.in

2016-05-06

The properties of lead free piezoelectric materials can be tuned by suitable doping in the A and B sites of the perovskite structure. In the present study, cerium has been identified as a dopant to investigate the piezoelectric properties of lead-free BCZT system. BCZT – 0.08 wt.%CeO{sub 2} lead-free ceramics have been synthesized using sol-gel technique and the effects of CeO{sub 2} dopant on their phase structure and piezoelectric properties were investigated systematically. Poling conditions, such as temperature, electric field, and poling time have been optimized to get enhanced piezoelectric response. The optimized poling conditions (50°C, 3Ec and 30min) resultedmore » in high piezoelectric charge coefficient d{sub 33} ~ 670pC/N, high electromechanical coupling coefficient k{sub p} ~ 60% and piezoelectric voltage coefficient g{sub 33} ~ 14 mV.m/N for BCZT – 0.08wt.% CeO{sub 2} ceramics.« less

Can a Drill Guide Improve the Coracoid Graft Placement During the Latarjet Procedure? A Prospective Comparative Study With the Freehand Technique.

PubMed

Barth, Johannes; Boutsiadis, Achilleas; Neyton, Lionel; Lafosse, Laurent; Walch, Gilles

2017-10-01

One of the factors that can affect the success of the Latarjet procedure is accurate coracoid graft (CG) placement. The use of a guide can improve placement of the CG and screw positioning in the sagittal and axial planes as compared with the classic open ("freehand") technique. Cohort study; Level of evidence, 2. A total of 49 patients who underwent a Latarjet procedure for the treatment of recurrent anterior shoulder instability were prospectively included; the procedure was performed with the freehand technique in 22 patients (group 1) and with use of a parallel drill guide during screw placement in 27 patients (group 2). All patients underwent a postoperative computed tomography scan with the same established protocol. The scans were used to evaluate and compare the position of the CG in the sagittal and axial planes, the direction of the screws (α angle), and overall contact of the graft with the anterior surface of the glenoid after the 2 surgical techniques. The CG was placed >60% below the native glenoid equator in 23 patients (85.2%) in group 2, compared with 14 patients (63.6%) in group 1 ( P = .004). In the axial plane, the position of the CG in group 2 patients was more accurate (85.2% and 88.9% flush) at the inferior and middle quartiles of the glenoid surface ( P = .012 and .009), respectively. Moreover, with the freehand technique (group 1), the graft was in a more lateral position in the inferior and middle quartiles ( P = .012 and .009, respectively). No differences were found between groups 1 and 2 regarding the mean α angle of the superior (9° ± 4.14° vs 11° ± 6.3°, P = .232) and inferior (9.5° ± 6° vs 10° ± 7.5°, P = .629) screws. However, the mean contact angle (angle between the posterior coracoid and the anterior glenoid surface) with the freehand technique (3.8° ± 6.8°) was better than that of the guide (8.55° ± 8°) ( P = .05). Compared with the classic freehand operative technique, the parallel drill guide can ensure more accurate placement of the CG in the axial and sagittal planes, although with inferior bone contact.

Accuracy of pedicle screw placement comparing robot-assisted technology and the free-hand with fluoroscopy-guided method in spine surgery: An updated meta-analysis.

PubMed

Fan, Yong; Du, Jin Peng; Liu, Ji Jun; Zhang, Jia Nan; Qiao, Huan Huan; Liu, Shi Chang; Hao, Ding Jun

2018-06-01

A miniature spine-mounted robot has recently been introduced to further improve the accuracy of pedicle screw placement in spine surgery. However, the differences in accuracy between the robotic-assisted (RA) technique and the free-hand with fluoroscopy-guided (FH) method for pedicle screw placement are controversial. A meta-analysis was conducted to focus on this problem. Several randomized controlled trials (RCTs) and cohort studies involving RA and FH and published before January 2017 were searched for using the Cochrane Library, Ovid, Web of Science, PubMed, and EMBASE databases. A total of 55 papers were selected. After the full-text assessment, 45 clinical trials were excluded. The final meta-analysis included 10 articles. The accuracy of pedicle screw placement within the RA group was significantly greater than the accuracy within the FH group (odds ratio 95%, "perfect accuracy" confidence interval: 1.38-2.07, P < .01; odds ratio 95% "clinically acceptable" Confidence Interval: 1.17-2.08, P < .01). There are significant differences in accuracy between RA surgery and FH surgery. It was demonstrated that the RA technique is superior to the conventional method in terms of the accuracy of pedicle screw placement.

The Nelaton Catheter Guard for Safe and Effective Placement of Subdural Drain for Two-Burr-Hole Trephination in Chronic Subdural Hematoma: A Technical Note.

PubMed

Fichtner, Jens; Beck, Jürgen; Raabe, A; Stieglitz, Lennart Henning

2015-09-01

For chronic subdural hematoma, placement of a Blake drain with a two-burr-hole craniotomy is often preferred. However, the placement of such drains carries the risk of penetrating the brain surface or damaging superficial venous structures. To describe the use of a Nelaton catheter for the placement of a subdural drain in two-burr-hole trephination for chronic subdural hematoma. A Nelaton catheter was used to guide placement of a Blake drain into the subdural hematoma cavity and provide irrigation of the hematoma cavity. With the two-burr-hole method, the Nelaton catheter could be removed easily via the frontal burr hole after the Blake drain was in place. We used the Nelaton catheters in many surgical procedures and found it a safe and easy technique. This method allows the surgeon to safely direct the catheter into the correct position in the subdural space. This tool has two advantages. First, the use of a small and flexible Nelaton catheter is a safe method for irrigation of a chronic subdural hematoma cavity. Second, in comparison with insertion of subdural drainage alone through a burr hole, the placement of the Nelaton catheter in subdural space is easier and the risk of damaging relevant structures such as cortical tissue or bridging veins is lower. Thus this technique may help to avoid complications when placing a subdural drain. Georg Thieme Verlag KG Stuttgart · New York.

Breast Reduction versus Breast Reduction Plus Implants: A Comparative Study with Measurements and Outcomes

PubMed Central

2014-01-01

Background: Breast reduction is well-known to provide an improvement in physical symptoms. However, measurements show that this procedure is less effective in restoring upper-pole fullness. Breast implants effectively augment the upper pole. This study was undertaken to determine the effectiveness and safety of this treatment combination. Methods: This retrospective study consists of 3 parts: (1) a clinical study, (2) breast measurements, and (3) an outcome study. Eighty consecutive women undergoing breast reduction (n = 56) or breast reduction plus implants (n = 24) were evaluated. All breast implants were inserted submuscularly. All patients were treated with the same vertical reduction technique, using a medially based pedicle and intraoperative nipple positioning. Measurements were compared between preoperative photographs and photographs taken at least 3 months after surgery (n = 51). Patient surveys (n= 56) were evaluated. Results: There was no significant difference in complication or reoperation rates between groups. Both procedures elevated the breast mound and lower-pole level and increased the breast parenchymal ratio (upper-pole area/lower-pole area). Breast implants significantly increased upper-pole projection (P < 0.01). All surveyed patients who had simultaneous implants reported that they were pleased with their decision. Physical symptoms were reduced in both groups. Patient satisfaction was 92.5% for breast reduction and 93.8% for breast reduction plus implants. Both groups reported an improvement in quality of life. Conclusions: Vertical breast reduction with a medial pedicle may be combined safely and effectively with breast implants in patients who desire upper-pole fullness. PMID:25587515

25 CFR 26.27 - What kind of Job Placement support services can I expect?

Code of Federal Regulations, 2010 CFR

2010-04-01

... resume preparation, interview techniques, job retention, and related living skills. ... 25 Indians 1 2010-04-01 2010-04-01 false What kind of Job Placement support services can I expect? 26.27 Section 26.27 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB...

Advanced Placement Course Enrollment and School-Level Characteristics

ERIC Educational Resources Information Center

Barnard-Brak, Lucy; McGaha-Garnett, Valerie; Burley, Hansel

2011-01-01

The current study examined access to Advanced Placement (AP) courses as a function of these school characteristics (e.g., percentage of ethnic minority and lower socioeconomic status) and then examined AP course enrollment as a function of both access to AP courses and these school characteristics. Using structural equation modeling techniques,…

Preparing Students for Advanced Placement Spanish Literature: Content Sequencing of the Reading Skill.

ERIC Educational Resources Information Center

Stein, Roger D.

1985-01-01

Describes a reading-skill-building curriculum that prepares students to handle the reading in the Advanced Placement Spanish Literature course, a course that treats the works of Borges, Garcia Lorca, Matute, Neruda, and Unamuno. Suggests techniques and texts that aid in the teaching of these skills. (SED)

A Multifactor Ecosystem Assessment of Wetlands Created Using a Novel Dredged Material Placement Technique in the Atchafalaya River, Louisiana: An Engineering With Nature Demonstration Project

DTIC Science & Technology

functions. The strategic placement of dredged materials in locations that mimic natural process promoted additional ecological benefits, especially...regarding wading bird and infaunal habitat, thus adhering to Engineering With Nature (EWN) processes. The multifactor approach improved the wetland

Expression of Emotion Through Family Grouping Schemata, Distance, and Interpersonal Focus

ERIC Educational Resources Information Center

Gerber, Gwen L.; Kaswan, Jaques

1971-01-01

A family doll placement technique was used to study separateness and connectedness within the family as this varies over positive and negative emotional themes. As hypothesized, positive emotional themes were represented by closer doll placements than negative themes. Emotions were also characterized by using certain kinds of groupings and…

The Community College Student: Preparation for the Math Placement Test

ERIC Educational Resources Information Center

Dudley, Jennifer

2010-01-01

The purpose of this action research case study was to explore attitudes and beliefs regarding strategies to improve math placement scores for low-socioeconomic community college students at an urban campus. Using a pragmatic worldview, qualitative techniques were used to gather data to explore this problem at a single community college located in…

Advances in circular stapling technique for gastric bypass: transoral placement of the anvil.

PubMed

Nguyen, Ninh T; Hinojosa, Marcelo W; Smith, Brian R; Reavis, Kevin M; Wilson, Samuel E

2008-05-01

In Roux-en-Y gastric bypass, construction of the gastrojejunostomy is commonly performed using a circular stapler. The initial description for placement of the anvil was via the transoral approach. Although the concept was ingenious, technical difficulty was encountered during passage resulting in complications such as hypopharyngeal perforation and esophageal mucosal injury. As a result, most surgeons subsequently changed their route of anvil placement to the transabdominal approach. Advances in stapler technology now allow the head of the anvil to be pre-tilted, permitting transoral introduction with greater ease and safety. This paper describes this improved method for transoral placement of the anvil during laparoscopic gastric bypass and reoperative bariatric surgery.

Minimal invasive epicardial lead implantation: optimizing cardiac resynchronization with a new mapping device for epicardial lead placement.

PubMed

Maessen, J G; Phelps, B; Dekker, A L A J; Dijkman, B

2004-05-01

To optimize resynchronization in biventricular pacing with epicardial leads, mapping to determine the best pacing site, is a prerequisite. A port access surgical mapping technique was developed that allowed multiple pace site selection and reproducible lead evaluation and implantation. Pressure-volume loops analysis was used for real time guidance in targeting epicardial lead placement. Even the smallest changes in lead position revealed significantly different functional results. Optimizing the pacing site with this technique allowed functional improvement up to 40% versus random pace site selection.

Laser Interstitial Thermal Therapy Technology, Physics of Magnetic Resonance Imaging Thermometry, and Technical Considerations for Proper Catheter Placement During Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy.

PubMed

Patel, Nitesh V; Mian, Matthew; Stafford, R Jason; Nahed, Brian V; Willie, Jon T; Gross, Robert E; Danish, Shabbar F

2016-12-01

Laser-induced thermal therapy has become a powerful tool in the neurosurgical armamentarium. The physics of laser therapy are complex, but a sound understanding of this topic is clinically relevant, as many centers have incorporated it into their treatment algorithm, and educated patients are demanding consideration of its use for their disease. Laser ablation has been used for a wide array of intracranial lesions. Laser catheter placement is guided by stereotactic planning; however, as the procedure has popularized, the number of ways in which the catheter can be inserted has also increased. There are many technical nuances for laser placement, and, to date, there is not a clear understanding of whether any one technique is better than the other. In this review, we describe the basic physics of magnetic resonance-guided laser-induced thermal therapy and describe the several common techniques for accurate Visualase laser catheter placement in a stepwise fashion. MRg-LITT, magnetic resonance-guided laser-induced thermal therapyPAD, precision aiming device.

Imaging and intervention in the gastrointestinal tract in children.

PubMed

Kaye, Robin D; Towbin, R B

2002-09-01

Vascular and interventional techniques have become an integral component of modern pediatric healthcare. Minimally invasive procedures of the gastrointestinal tract now comprise a large part of any active pediatric interventional practice. Magnetic resonance cholangiopancreatography offers a reliable, non-invasive means to evaluate patients with possible pancreatic or biliary pathology. This article reviews treatment of esophageal strictures and placement of gastronomy and gastrojejunostomy tubes and discusses new developments. Placement of percutaneous cecostomy tubes is a relatively new procedure that creatively uses the techniques developed for placement of percutaneous gastronomy tubes. This procedure offers significant benefits and lasting positive lifestyle changes for patients suffering from fecal incontinence. Liver biopsy in high-risk patients can be performed safely using measures designed to significantly decrease the risk of post-biopsy hemorrhage, such as track embolization or the transjugular approach.

[How to do - the chest tube drainage].

PubMed

Klopp, Michael; Hoffmann, Hans; Dienemann, Hendrik

2015-03-01

A chest tube is used to drain the contents of the pleural space to reconstitute the physiologic pressures within the pleural space and to allow the lungs to fully expand. Indications for chest tube placement include pneumothorax, hemothorax, pleural effusion, pleural empyema, and major thoracic surgery. The most appropriate site for chest tube placement is the 4th or 5th intercostal space in the mid- or anterior- axillary line. Attention to technique in placing the chest tube is vital to avoid complications from the procedure. Applying the step-by-step technique presented, placement of a chest tube is a quick and safe procedure. Complications - frequently occurring when the tube is inserted with a steel trocar - include hemothorax, dislocation, lung lacerations, and injury to organs in the thoracic or abdominal cavity." © Georg Thieme Verlag KG Stuttgart · New York.

Disadvantages and advantages of transtibial technique for creating the anterior cruciate ligament femoral socket.

PubMed

Robin, Brett N; Lubowitz, James H

2014-10-01

Anterior cruciate ligament (ACL) femoral socket techniques have distinct advantages and disadvantages when considering the following techniques: transtibial, anteromedial portal, outside-in, and outside-in retroconstruction. There is no one perfect technique and we have an incomplete understanding of anatomical, biomechanical, isometry, stability, and clinical outcomes. Our primary focus is transtibial technique for creating the ACL femoral socket. Advantages include less invasive, isometric graft placement, stable Lachman exam, and minimal graft impingement with the tunnel and notch. Disadvantages include nonanatomic vertical graft placement that can cause rotational instability and positive pivot shift, interference screw divergence, graft-tunnel length mismatch, femoral socket constraint, posterior cruciate ligament impingement, and a short, oblique tibial tunnel that may undermine the medial plateau in an attempt to achieve anatomic ACL reconstruction. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Blind bedside postpyloric placement of spiral tube as rescue therapy in critically ill patients: a prospective, tricentric, observational study.

PubMed

Lv, Bo; Hu, Linhui; Chen, Lifang; Hu, Bei; Zhang, Yanlin; Ye, Heng; Sun, Cheng; Zhang, Xiunong; Lan, Huilan; Chen, Chunbo

2017-09-26

Various special techniques for blind bedside transpyloric tube placement have been introduced into clinical practice. However, transpyloric spiral tube placement facilitated by a blind bedside method has not yet been reported. The objective of this prospective study was to evaluate the safety and efficiency of blind bedside postpyloric placement of a spiral tube as a rescue therapy subsequent to failed spontaneous transpyloric migration in critically ill patients. This prospective, tricentric, observational study was conducted in the intensive care units (ICUs) of three tertiary hospitals. A total of 127 consecutive patients with failed spontaneous transpyloric spiral tube migration despite using prokinetic agents and still required enteral nutrition for more than 3 days were included. The spiral tube was inserted postpylorically using the blind bedside technique. All patients received metoclopramide intravenously prior to tube insertion. The exact tube tip position was determined by radiography. The primary efficacy endpoint was the success rate of postpyloric spiral tube placement. Secondary efficacy endpoints were success rate of a spiral tube placed in the third portion of the duodenum (D3) or beyond, success rate of placement in the proximal jejunum, time to insertion, length of insertion, and number of attempts. Safety endpoints were metoclopramide-related and major adverse tube-associated events. In 81.9% of patients, the spiral feeding tubes were placed postpylorically; of these, 55.1% were placed in D3 or beyond and 33.9% were placed in the proximal jejunum, with a median time to insertion of 14 min and an average number of attempts of 1.4. The mean length of insertion was 95.6 cm. The adverse event incidence was 26.0%, and no serious adverse event was observed. Blind bedside postpyloric placement of a spiral tube, as a rescue therapy subsequent to failed spontaneous transpyloric migration in critically ill patients, is safe and effective. This technique may facilitate the early initiation of postpyloric feeding in the ICU. Chinese Clinical Trial Registry, ChiCTR-OPN-16008206 . Registered on 1 April 2016.

Self-Assembly of MinE on the Membrane Underlies Formation of the MinE Ring to Sustain Function of the Escherichia coli Min System*

PubMed Central

Zheng, Min; Chiang, Ya-Ling; Lee, Hsiao-Lin; Kong, Lih-Ren; Hsu, Shang-Te Danny; Hwang, Ing-Shouh; Rothfield, Lawrence I.; Shih, Yu-Ling

2014-01-01

The pole-to-pole oscillation of the Min proteins in Escherichia coli results in the inhibition of aberrant polar division, thus facilitating placement of the division septum at the midcell. MinE of the Min system forms a ring-like structure that plays a critical role in triggering the oscillation cycle. However, the mechanism underlying the formation of the MinE ring remains unclear. This study demonstrates that MinE self-assembles into fibrillar structures on the supported lipid bilayer. The MinD-interacting domain of MinE shows amyloidogenic properties, providing a possible mechanism for self-assembly of MinE. Supporting the idea, mutations in residues Ile-24 and Ile-25 of the MinD-interacting domain affect fibril formation, membrane binding ability of MinE and MinD, and subcellular localization of three Min proteins. Additional mutations in residues Ile-72 and Ile-74 suggest a role of the C-terminal domain of MinE in regulating the folding propensity of the MinD-interacting domain for different molecular interactions. The study suggests a self-assembly mechanism that may underlie the ring-like structure formed by MinE-GFP observed in vivo. PMID:24914211

SFG synthesis of general high-order all-pass and all-pole current transfer functions using CFTAs.

PubMed

Tangsrirat, Worapong

2014-01-01

An approach of using the signal flow graph (SFG) technique to synthesize general high-order all-pass and all-pole current transfer functions with current follower transconductance amplifiers (CFTAs) and grounded capacitors has been presented. For general nth-order systems, the realized all-pass structure contains at most n + 1 CFTAs and n grounded capacitors, while the all-pole lowpass circuit requires only n CFTAs and n grounded capacitors. The resulting circuits obtained from the synthesis procedure are resistor-less structures and especially suitable for integration. They also exhibit low-input and high-output impedances and also convenient electronic controllability through the g m-value of the CFTA. Simulation results using real transistor model parameters ALA400 are also included to confirm the theory.

SFG Synthesis of General High-Order All-Pass and All-Pole Current Transfer Functions Using CFTAs

PubMed Central

Tangsrirat, Worapong

2014-01-01

An approach of using the signal flow graph (SFG) technique to synthesize general high-order all-pass and all-pole current transfer functions with current follower transconductance amplifiers (CFTAs) and grounded capacitors has been presented. For general nth-order systems, the realized all-pass structure contains at most n + 1 CFTAs and n grounded capacitors, while the all-pole lowpass circuit requires only n CFTAs and n grounded capacitors. The resulting circuits obtained from the synthesis procedure are resistor-less structures and especially suitable for integration. They also exhibit low-input and high-output impedances and also convenient electronic controllability through the g m-value of the CFTA. Simulation results using real transistor model parameters ALA400 are also included to confirm the theory. PMID:24688375

Flagellation of Pseudomonas aeruginosa in newly divided cells

NASA Astrophysics Data System (ADS)

Zhao, Kun; Lee, Calvin; Anda, Jaime; Wong, Gerard

2015-03-01

For monotrichous bacteria, Pseudomonas aeruginosa, after cell division, one daughter cell inherits the old flagellum from its mother cell, and the other grows a new flagellum during or after cell division. It had been shown that the new flagellum grows at the distal pole of the dividing cell when the two daughter cells haven't completely separated. However, for those daughter cells who grow new flagella after division, it still remains unknown at which pole the new flagellum will grow. Here, by combining our newly developed bacteria family tree tracking techniques with genetic manipulation method, we showed that for the daughter cell who did not inherit the old flagellum, a new flagellum has about 90% chances to grow at the newly formed pole. We proposed a model for flagellation of P. aeruginosa.

Poling-assisted bleaching of soda-lime float glasses containing silver nanoparticles with a decreasing filling factor across the depth

NASA Astrophysics Data System (ADS)

Deparis, Olivier; Kazansky, Peter G.; Podlipensky, Alexander; Abdolvand, Amin; Seifert, Gerhard; Graener, Heinrich

2006-08-01

The recently discovered poling-assisted bleaching of glass with embedded silver nanoparticles has renewed the interest in thermal poling as a simple, reliable, and low-cost technique for controlling locally the surface-plasmon-resonant optical properties of metal-doped nanocomposite glasses. In the present study, the emphasis is put on the influence of the volume filling factor of metallic clusters on poling-assisted bleaching. Soda-lime silicate glass samples containing spherical silver nanoparticles with a decreasing filling factor across the depth were subject to thermal poling experiments with various poling temperatures, voltages, and times. Optical extinction spectra were measured from ultraviolet to near-infrared ranges and the surface-plasmon-resonant extinction due to silver nanoparticles (around 410nm) was modeled by the Maxwell Garnett [Philos. Trans. R. Soc. London, Ser. A 203, 385 (1904); 205, 237 (1906)] effective medium theory which was adapted in order to take into account the filling factor depth profile. A method was proposed for the retrieval of the filling factor depth profile from optical extinction spectra recorded in fresh and chemically etched samples. A stretched exponential depth profile turned out to be necessary in order to model samples having a high filling factor near the surface. Based on the fact that the electric-field-assisted dissolution of embedded metallic nanoparticles proceeded progressively from the top surface, a bleaching front was defined that moved forward in depth as time elapsed. The position of the bleaching front was determined after each poling experiment by fitting the measured extinction spectrum to the theoretical one. In samples with higher peak value and steeper gradient of the filling factor, the bleaching front reached more rapidly a steady-state depth as poling time increased. Also it increased less strongly with increasing poling voltage. These results were in agreement with the physics of the dissolution process. Finally, clear evidence of injection of hydrogenated ionic species from the atmosphere into the sample during poling was obtained from the growth of the infrared extinction peak associated with OH radicals.

ACL Roof Impingement Revisited: Does the Independent Femoral Drilling Technique Avoid Roof Impingement With Anteriorly Placed Tibial Tunnels?

PubMed

Tanksley, John A; Werner, Brian C; Conte, Evan J; Lustenberger, David P; Burrus, M Tyrrell; Brockmeier, Stephen F; Gwathmey, F Winston; Miller, Mark D

2017-05-01

Anatomic femoral tunnel placement for single-bundle anterior cruciate ligament (ACL) reconstruction is now well accepted. The ideal location for the tibial tunnel has not been studied extensively, although some biomechanical and clinical studies suggest that placement of the tibial tunnel in the anterior part of the ACL tibial attachment site may be desirable. However, the concern for intercondylar roof impingement has tempered enthusiasm for anterior tibial tunnel placement. To compare the potential for intercondylar roof impingement of ACL grafts with anteriorly positioned tibial tunnels after either transtibial (TT) or independent femoral (IF) tunnel drilling. Controlled laboratory study. Twelve fresh-frozen cadaver knees were randomized to either a TT or IF drilling technique. Tibial guide pins were drilled in the anterior third of the native ACL tibial attachment site after debridement. All efforts were made to drill the femoral tunnel anatomically in the center of the attachment site, and the surrogate ACL graft was visualized using 3-dimensional computed tomography. Reformatting was used to evaluate for roof impingement. Tunnel dimensions, knee flexion angles, and intra-articular sagittal graft angles were also measured. The Impingement Review Index (IRI) was used to evaluate for graft impingement. Two grafts (2/6, 33.3%) in the TT group impinged upon the intercondylar roof and demonstrated angular deformity (IRI type 1). No grafts in the IF group impinged, although 2 of 6 (66.7%) IF grafts touched the roof without deformation (IRI type 2). The presence or absence of impingement was not statistically significant. The mean sagittal tibial tunnel guide pin position prior to drilling was 27.6% of the sagittal diameter of the tibia (range, 22%-33.9%). However, computed tomography performed postdrilling detected substantial posterior enlargement in 2 TT specimens. A significant difference in the sagittal graft angle was noted between the 2 groups. TT grafts were more vertical, leading to angular convergence with the roof, whereas IF grafts were more horizontal and universally diverged from the roof. The IF technique had no specimens with roof impingement despite an anterior tibial tunnel position, likely due to a more horizontal graft trajectory and anatomic placement of the ACL femoral tunnel. Roof impingement remains a concern after TT ACL reconstruction in the setting of anterior tibial tunnel placement, although statistical significance was not found. Future clinical studies are planned to develop better recommendations for ACL tibial tunnel placement. Graft impingement due to excessively anterior tibial tunnel placement using a TT drilling technique has been previously demonstrated; however, this may not be a concern when using an IF tunnel drilling technique. There may also be biomechanical advantages to a more anterior tibial tunnel in IF tunnel ACL reconstruction.

A New Approach to an Old Technique-The S.U.T.R. First Technique.

PubMed

Jones, Frank; Lewis, Catherine; Knight, Darryl; Bacon, Louise; Patel, Vijay; Moore, Carolyn

2018-04-01

Ventral and incisional hernias of the abdominal wall are common problems treated by surgeons around the globe. Incisional hernias are common postoperative complications of abdominal laparotomies with a reported incidence of up to 20 per cent. The increasing use of prosthetic mesh in open ventral hernia repairs necessitated the development of different operative techniques used in the repairs. It also required that surgeons become facile with placement of the mesh in different anatomical positions on the abdominal wall. One of the most common locations is placement of the mesh in the underlay position. Many surgeons who use the underlay technique have expressed significant concerns. Among these are fear of an inadvertent bowel injury while placing the mesh, poor visualization during mesh placement, and the inability to use the underlay technique for difficult hernias. We present a very useful, if not, novel technique of open hernia repair using mesh in the underlay position that helps to 1) prevent complications, 2) facilitate easier mesh fixation, 3) simplify open repair of atypical ventral hernias, and 4) reduce total operative time while still adhering to the important fundamental principles of a tension-free hernia repair. This technique as we describe it has been compared with the old parachute technique, but we think this is a significant improvement of that seldom used technique. We believe the use of this technique for the underlay position makes open ventral hernia repair safer, faster, and easier; however, our goal for this article is to describe the procedure in detail. In addition, we recently have started using this technique to fix the mesh when doing the retrorectus approach as well.

Efficacy of the Stonehenge Technique for Minimally Invasive Aortic Valve Replacement via Right Infraaxillary Thoracotomy.

PubMed

Yamazaki, Masataka; Kin, Hajime; Kitamoto, Shohei; Yamanaka, Shota; Nishida, Hidefumi; Nishigawa, Kosaku; Takanashi, Shuichiro

2017-02-20

Minimally invasive cardiac surgeries for aortic valve replacement (AVR) are still a technical challenge for surgeons because these procedures are undertaken through small incisions and deep surgical fields. Although AVR via vertical infraaxillary thoracotomy can be a cosmetically superior option, a disadvantage of this approach is the distance between the thoracotomy incision and the ascending aorta. Therefore, we devised a technique to perform all manipulations using the fingertips without the aid of a knot pusher or long-shafted surgical instruments. This was achieved by particular placement of several retracted sutures to the right chest wall. We named placement of these sutures the "Stonehenge technique." In conclusion, AVR via vertical infraaxillary thoracotomy with our Stonehenge technique can be safely and simply performed with superior cosmetic advantages.

Drilling the femoral tunnel during ACL reconstruction: transtibial versus anteromedial portal techniques.

PubMed

Tudisco, Cosimo; Bisicchia, Salvatore

2012-08-01

Incorrect bone tunnel position, particularly on the femoral side, is a frequent cause of failed anterior cruciate ligament reconstruction. Several studies have reported that drilling the femoral tunnel through the anteromedial portal allows a more anatomical placement on the lateral femoral condyle and higher knee stability than does transtibial reconstruction.In the current study, the femoral tunnel was drilled with transtibial (n=6) and anteromedial (n=6) portal techniques in 12 cadaveric knees. With appropriate landmarks inserted into bone tunnels, the direction and length of the tunnels were determined on anteroposterior and lateral radiographs. Knee stability was evaluated with a KT1000 arthrometer (MEDmetric Corporation, San Diego, California) and pivot shift test, comparing the pre- and postoperative values of both techniques. Finally, all knees were dissected to enhance vision of the insertion of the reconstructed ligament. The anteromedial portal technique led to better placement of the femoral tunnel in the coronal and sagittal planes, with higher knee stability according to the pivot shift test but not the KT1000 arthrometer. Anatomical and clinical results reported in the literature on transtibial and anteromedial portal techniques are controversial, but most of studies report better results with the anteromedial portal technique, especially regarding rotational stability. The current cadaveric study showed that the anteromedial portal technique provided better tunnel placement on the lateral femoral condyle in the coronal and sagittal planes, with an improvement in the rotational stability of the knee. Copyright 2012, SLACK Incorporated.

Stereolithographic Surgical Template: A Review

PubMed Central

Dandekeri, Shilpa Sudesh; Sowmya, M.K.; Bhandary, Shruthi

2013-01-01

Implant placement has become a routine modality of dental care.Improvements in surgical reconstructive methods as well as increased prosthetic demands,require a highly accurate diagnosis, planning and placement. Recently,computer-aided design and manufacturing have made it possible to use data from computerised tomography to not only plan implant rehabilitation,but also transfer this information to the surgery.A review on one of this technique called Stereolithography is presented in this article.It permits graphic and complex 3D implant placement and fabrication of stereolithographic surgical templates. Also offers many significant benefits over traditional procedures. PMID:24179955

Optimal placement of tuning masses on truss structures by genetic algorithms

NASA Technical Reports Server (NTRS)

Ponslet, Eric; Haftka, Raphael T.; Cudney, Harley H.

1993-01-01

Optimal placement of tuning masses, actuators and other peripherals on large space structures is a combinatorial optimization problem. This paper surveys several techniques for solving this problem. The genetic algorithm approach to the solution of the placement problem is described in detail. An example of minimizing the difference between the two lowest frequencies of a laboratory truss by adding tuning masses is used for demonstrating some of the advantages of genetic algorithms. The relative efficiencies of different codings are compared using the results of a large number of optimization runs.

The Free-Hand Technique for S2-Alar-Iliac Screw Placement: A Safe and Effective Method for Sacropelvic Fixation in Adult Spinal Deformity.

PubMed

Shillingford, Jamal N; Laratta, Joseph L; Tan, Lee A; Sarpong, Nana O; Lin, James D; Fischer, Charla R; Lehman, Ronald A; Kim, Yongjung J; Lenke, Lawrence G

2018-02-21

Spinopelvic fixation is an integral part of achieving solid fusion across the lumbosacral junction, especially in deformity procedures requiring substantial correction or long-segment constructs. Traditional S2-alar-iliac (S2AI) screw-placement techniques utilize fluoroscopy, increasing operative time and radiation exposure to the patient and surgeon. We describe a novel free-hand technique for S2AI screw placement in patients with adult spinal deformity. We reviewed the records of 45 consecutive patients who underwent spinopelvic fixation performed with use of S2AI screws by the senior surgeon and various fellows or residents over a 12-month period (2015 to 2016). In each case, the S2AI screws were placed utilizing a free-hand technique without fluoroscopic or image guidance. Screw position and accuracy were assessed by intraoperative O-arm imaging and analyzed using 3-dimensional interactive manipulation of computed tomography images. A total of 100 screws were placed, 51 by the senior surgeon and 49 by trainees. The mean patient age was 57.4 ± 12.7 years at the time of surgery; 37 (82.2%) of the patients were female. Preoperative diagnoses included adult idiopathic scoliosis (n = 19), adult degenerative scoliosis (n = 15), flatback syndrome (n = 2), fixed sagittal imbalance (n = 6), and distal junctional kyphosis (n = 3). Five (5%) of the screws were placed with moderate to severe cortical breaches, all of which perforated the pelvis posteriorly, with no clinically notable neurovascular or visceral complications. The breach rate did not differ significantly between the senior surgeon and trainees. The free-hand technique for S2AI screw placement, when performed in a standardized manner, was demonstrated to be safe and reliable in constructs requiring spinopelvic fixation. The accuracy of screw placement relies on visible and palpable anatomic landmarks that obviate the need for intraoperative fluoroscopy or image guidance, potentially reducing operative time and radiation exposure. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Fabrication and Characterization of Linear and Nonlinear Photonic Devices in Fused Silica by Femtosecond Laser Writing

NASA Astrophysics Data System (ADS)

Ng, Jason Clement

Femtosecond laser processing is a flexible, three-dimensional (3D) fabrication technique used to make integrated low-loss photonic devices in fused silica. My work expanded the suite of available optical devices through the design and optimization of linear optical components such as low-loss (< 0.5 dB) curved waveguides, directional couplers (DCs), and Mach-Zehnder interferometers (MZIs). The robustness and consistency of this maturing fabrication process was also reinforced through the scalable design and integration of a more complex, multi-component flat-top interleaver over a wide >70-nm spectral window. My work further complemented femtosecond laser processing with the development of nonlinear device capabilities. While thermal poling is a well known process, significant challenges had restricted the development of nonlinear devices in fused silica. The laser writing process would erase the induced nonlinearity (erasing) while a written waveguide core acted as a barrier to the thermal poling process (blocking). Using second harmonic (SH) microscopy, the effectiveness of thermal poling on laser-written waveguides was systematically analyzed leading to the technique of "double poling", which effectively overcomes the two challenges of erasing and blocking. In this new process the substrate is poled before and after waveguide writing to restore the induced nonlinearity within the vicinity of the waveguide to enable effective poling for inducing a second-order nonlinearity (SON) in fused silica. A new flexible, femtosecond laser based erasure process was also developed to enable quasi-phase matching and to form arbitrarily chirped gratings. Following this result, second harmonic generation (SHG) in a quasiphase-matched (QPM) femtosecond laser written waveguide device was demonstrated. SHG in a chirped QPM structure was also demonstrated to illustrate the flexibility of the femtosecond laser writing technique. These are the first demonstration of frequency doubling in an all-femtosecond-laser-written structure. A maximum SHG conversion efficiency of 1.3 +/- 0.1x10 -11/W-cm-2 was achieved for the fundamental wavelength of 1552.8 nm with a phase-matching bandwidth of 4.4 nm for a 10.0-mm-long waveguide. For a shorter sample, an effective SON of chi(2) = 0:020 +/- 0:002 pm/V was measured. The results collectively demonstrate the versatility of femtosecond laser additive and subtractive fabrication and opens up the development of integrated nonlinear applications and photonic devices for future lab-on-a-chip and lab-in-a-fiber devices.

Validity of computed tomography in predicting scaphoid screw prominence: a cadaveric study.

PubMed

Griffis, Clare E; Olsen, Cara; Nesti, Leon; Gould, C Frank; Frew, Michael; McKay, Patricia

2017-04-01

Studies of hardware protrusion into joint spaces following fracture fixation have been performed to address whether or not there is discrepancy between the actual and radiographic appearance of screw prominence. The purpose of our study was to prove that, with respect to the scaphoid, prominence as visualized on CT scan is real and not a result of metal artifact. Forty-two cadaveric wrists were separated into four allotted groups with 21 control specimens and 21 study specimens. All specimens were radiographically screened to exclude those with inherent carpal abnormalities. Acutrak® headless compression screws were placed into all specimens using an open dorsal approach. Cartilage was removed from screw insertion site at the convex surface of the scaphoid proximal pole. Control specimens had 0 mm screw head prominence. The studied specimens had 1, 2, and 3 mm head prominence measured with a digital caliper. Computed tomography, with direct sagittal acquisition and metal suppression technique, was then performed on all specimens following screw placement. Two staff radiologists blinded to the study groups interpreted the images. Results revealed that only one of 21 control specimens was interpreted as prominent. Comparatively, in the studied groups, 90% were accurately interpreted as prominent. CT provides an accurate assessment of scaphoid screw head prominence. When a screw appears prominent on CT scan, it is likely to be truly prominent without contribution from metallic artifact.

Endoscopic-Assisted Burr Hole Reservoir and Ventricle Catheter Placement.

PubMed

Antes, Sebastian; Tschan, Christoph A; Heckelmann, Michael; Salah, Mohamed; Senger, Sebastian; Linsler, Stefan; Oertel, Joachim

2017-05-01

Accurate positioning of a ventricle catheter is of utmost importance. Various techniques to ensure optimal positioning have been described. Commonly, after catheter placement, additional manipulation is necessary to connect a burr hole reservoir or shunt components. This manipulation can lead to accidental catheter dislocation and should be avoided. Here, we present a new technique that allows direct endoscopic insertion of a burr hole reservoir with an already mounted ventricle catheter. Before insertion, the ventricle catheter was slit at the tip, shortened to the correct length, and connected to the special burr hole reservoir. An intracatheter endoscope was then advanced through the reservoir and the connected catheter. This assemblage allowed using the endoscope as a stylet for shielded ventricular puncture. To confirm correct placement of the ventricle catheter, the endoscope was protruded a few millimeters beyond the catheter tip for inspection. The new technique was applied in 12 procedures. The modified burr hole reservoir was inserted for first-time ventriculoperitoneal shunting (n = 1), cerebrospinal fluid withdrawals and drug administration (n = 2), or different stenting procedures (n = 9). Optimal positioning of the catheter was achieved in 11 of 12 cases. No subcutaneous cerebrospinal fluid collection or fluid leakage through the wound occurred. No parenchymal damage or bleeding appeared. The use of the intracatheter endoscope combined with the modified burr hole reservoir provides a sufficient technique for accurate and safe placement. Connecting the ventricle catheter to the reservoir before the insertion reduces later manipulation and accidental dislocation of the catheter. Copyright © 2017 Elsevier Inc. All rights reserved.

Teachers of Advertising Media Courses Describe Techniques, Show Computer Applications.

ERIC Educational Resources Information Center

Lancaster, Kent M.; Martin, Thomas C.

1989-01-01

Reports on a survey of university advertising media teachers regarding textbooks and instructional aids used, teaching techniques, computer applications, student placement, instructor background, and faculty publishing. (SR)

Open-loop frequency acquisition for suppressed-carrier biphase signals using one-pole arm filters

NASA Technical Reports Server (NTRS)

Shah, B.; Holmes, J. K.

1991-01-01

Open loop frequency acquisition performance is discussed for suppressed carrier binary phase shift keyed signals in terms of the probability of detecting the carrier frequency offset when the arms of the Costas loop detector have one pole filters. The approach, which does not require symbol timing, uses fast Fourier transforms (FFTs) to detect the carrier frequency offset. The detection probability, which depends on both the 3 dB arm filter bandwidth and the received symbol signal to noise ratio, is derived and is shown to be independent of symbol timing. It is shown that the performance of this technique is slightly better that other open loop acquisition techniques which use integrators in the arms and whose detection performance varies with symbol timing.

Student Follow-Up Using Automated Record Linkage Techniques: Lessons from Florida's Education and Training Placement Information Program (FETPIP).

ERIC Educational Resources Information Center

Pfeiffer, Jay J.

Florida's Education and Training Placement Information Program (FETPIP) is a statewide system linking the administrative databases of certain state and federal agencies to collect follow-up data on former students or program participants. The databases that are collected include those of the Florida Department of Corrections; Florida Department of…

A Randomized Controlled Trial of Music Use During Epidural Catheter Placement on Laboring Parturient Anxiety, Pain, and Satisfaction.

PubMed

Drzymalski, Dan M; Tsen, Lawrence C; Palanisamy, Arvind; Zhou, Jie; Huang, Chuan-Chin; Kodali, Bhavani S

2017-02-01

Although music is frequently used to promote a relaxing environment during labor and delivery, the effect of its use during the placement of neuraxial techniques is unknown. Our study sought to determine the effects of music use on laboring parturients during epidural catheter placement, with the hypothesis that music use would result in lower anxiety, lower pain, and greater patient satisfaction. We conducted a prospective, randomized, controlled trial of laboring parturients undergoing epidural catheter placement with or without music. The music group listened to the patient's preferred music on a Pandora® station broadcast through an external amplified speaker; the control group listened to no music. All women received a standardized epidural technique and local anesthetic dose. The primary outcomes were 3 measures of anxiety. Secondary outcomes included pain, patient satisfaction, hemodynamic parameters, obstetric parameters, neonatal outcomes, and anesthesia provider anxiety. Intention-to-treat analysis with Bonferroni correction was used for the primary outcomes. For secondary outcomes, a P value of <.001 was considered statistically significant. A total of 100 parturients were randomly assigned, with 99 included in the intention-to-treat analysis. Patient characteristics were similar in both groups; in the music group, the duration of music use was 31.1 ± 7.7 minutes (mean ± SD). The music group experienced higher anxiety as measured by Numeric Rating Scale scores immediately after epidural catheter placement (2.9 ± 3.3 vs 1.4 ± 1.7, mean difference 1.5 [95% confidence interval {CI} 0.2-2.7], P = .02), and as measured by fewer parturients being "very much relaxed" 1 hour after epidural catheter placement (51% vs 78%, odds ratio {OR} 0.3 [95% CI 0.1-0.9], P = .02). No differences in mean pain scores immediately after placement or patient satisfaction with the overall epidural placement experience were observed; however, the desire for music use with future epidural catheter placements was higher in the music group (84% vs 45%, OR 6.4 [95% CI 2.5-16.5], P < .0001). No differences in the difficulty with the epidural catheter placement or in the rate of cesarean delivery were observed. Music use during epidural catheter placement in laboring parturients is associated with higher postprocedure anxiety and no improvement in pain or satisfaction; however, a stronger desire for music with future epidural catheter placements was observed. Further investigation is needed to determine the effect of music use in parturients requesting and using epidural labor analgesia.

Influence of surgical and prosthetic techniques on marginal bone loss around titanium implants. Part I: immediate loading in fresh extraction sockets.

PubMed

Berberi, Antoine N; Tehini, Georges E; Noujeim, Ziad F; Khairallah, Alexandre A; Abousehlib, Moustafa N; Salameh, Ziad A

2014-10-01

Delayed placement of implant abutments has been associated with peri-implant marginal bone loss; however, long-term results obtained by modifying surgical and prosthetic techniques after implant placement are still lacking. This study aimed to evaluate the marginal bone loss around titanium implants placed in fresh extraction sockets using two loading protocols after a 5-year follow-up period. A total of 36 patients received 40 titanium implants (Astra Tech) intended for single-tooth replacement. Implants were immediately placed into fresh extraction sockets using either a one-stage (immediate loading by placing an interim prosthesis into functional occlusion) or a two-stage prosthetic loading protocol (insertion of abutments after 8 weeks of healing time). Marginal bone levels relative to the implant reference point were evaluated at four time intervals using intraoral radiographs: at time of implant placement, and 1, 3, and 5 years after implant placement. Measurements were obtained from mesial and distal surfaces of each implant (α = 0.05). One-stage immediate implant placement into fresh extraction sockets resulted in a significant reduction in marginal bone loss (p < 0.002) compared to the traditional two-stage technique. Whereas mesial surfaces remained stable for the 5-year observation period, significant marginal bone loss was observed on distal surfaces of implants after cementation of interim prostheses (p < 0.007) and after 12 months (p < 0.034). Within the limitations of this study, immediate loading of implants placed into fresh extraction sockets reduced marginal bone loss and did not compromise the success rate of the restorations. © 2014 by the American College of Prosthodontists.

Creating a Strain Relief Loop during S1 Transforaminal Lead Placement for Dorsal Root Ganglion Stimulation for Foot Pain: A Technical Note.

PubMed

van Velsen, Valery; van Helmond, Noud; Chapman, Kenneth B

2018-04-01

Chronic neuropathic pain is often refractory to conventional medical treatments and leads to significant disability and socio-economic burden. Dorsal root ganglion (DRG) stimulation has recently emerged as a treatment for persistent neuropathic pain, but creating a strain relief loop at the S1 level has thus far been a challenging technical component of DRG lead placement. We describe a refined technique for strain relief loop formation at the S1 level using a transforaminal approach that we employed in a 45-year-old patient with intractable foot pain. We successfully placed a strain relief loop in the sacral space in a predictable and easily reproducible manner using a transforaminal anchorless approach. The patient experienced a decrease in visual analog pain score (85%), and improvement in function during the trial period, and proceeded with permanent implantation. The described sacral transforaminal strain relief loop formation technique appears to be a more reliable and predictable technique of DRG lead placement in the sacrum than those previously documented. © 2017 World Institute of Pain.

Findings from the experience with the punch technique for auditory osseointegrated implants: A retrospective single center comparative study.

PubMed

Bonilla, Alfonso; Magri, Carlos; Juan, Eulalia

To compare the punch technique and linear incision with soft tissue reduction for the placement of auditory osseointegrated implants (AOI) and analyze results of osseointegration obtained with the punch technique as measured with the Implant Stability Quotient (ISQ). Case review of 34 patients who received auditory osseointegrated implants between January 2010 and July 2015 and were divided into two groups according to the surgical technique: 18 with the punch technique (PT) and 16 with the linear incision technique (LI). Minimum follow-up was four months (mean: 24 months; range 4-64 months). Included in the analysis were patient profiles and records of the demographic data, surgical indications, surgical technique, implant placement, surgical time, intraoperative complications, as well as postsurgical complications (Holgers classification) and implant stability quotients (ISQ). Use of larger abutments was significantly greater in the PT group (PT, 10mm; LI, 6mm, p<0.001). The PT technique resulted in a shorter procedure than the LI (PT, 20min; LI, 45min, p<0.001). Holgers classification scores identified significantly fewer skin complications one week after surgery for the PT group; however, only small differences were seen between the two groups at the one- and three-month control visits. As shown for our cohort, the punch technique for surgical placement of AOI is faster and presents fewer immediate postoperative complications when compared to the linear incision technique. The clinical application of the ISQ is a useful, easy method to demonstrate the status of osseointegration and, thus, the stability of the device. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Gender differences in power production, energetic capacity and efficiency of elite cross‑country skiers during whole‑body, upper‑body, and arm poling.

PubMed

Hegge, Ann Magdalen; Bucher, Elias; Ettema, Gertjan; Faude, Oliver; Holmberg, Hans-Christer; Sandbakk, Øyvind

2016-02-01

To characterize gender differences in power output, energetic capacity and exercise efficiency during whole-body (WP), upper-body (UP), and arm poling (AP). Ten male and ten female elite cross-country skiers, matched for international performance level, completed three incremental submaximal tests and a 3-min self-paced performance test on a Concept2 SkiErg. Power output, cardiorespiratory and kinematic variables were monitored. Body composition was determined by dual-energy X-ray absorptiometry. The men demonstrated 87, 97 and 103% higher power output, and 51, 65 and 71% higher VO2peak (L min(−1)) than the women during WP, UP and AP, respectively, while utilizing ~10% more of their running VO2max in all modes (all P < 0.001). The men had 35, 38 and 59% more lean mass in the whole body, upper body and arms (all P < 0.001). The men exhibited greater shoulder and elbow extension at the start of poling and greater trunk flexion at the end of poling (all P < 0.05). The relationship between VO2 and power output did not differ between the men and women. Gender differences in power production and peak aerobic capacity increased sequentially from WP to UP to AP, coinciding with a greater portion of the muscle mass in the arms of the men. Although the men and women employed each poling technique differently, the estimated efficiency of double poling was independent of gender.

Modern methods of experimental construction of texture complete direct pole figures by using X-ray data

NASA Astrophysics Data System (ADS)

Isaenkova, M.; Perlovich, Yu; Fesenko, V.

2016-04-01

Currently used methods for constructing texture complete direct pole figure (CDPF) based on the results of X-ray diffractometric measurements were considered with respect to the products of Zr-based alloys and, in particular, used in a nuclear reactor cladding tubes, for which the accuracy of determination of integral texture parameters is of the especial importance. The main attention was devoted to technical issues which are solved by means of computer processing of large arrays of obtained experimental data. Among considered questions there are amendments of the defocusing, techniques for constructing of complete direct pole figures and determination of integral textural parameters. The methods of reconstruction of complete direct pole figures by partial direct pole figures recorded up to tilt angles of sample ψ=70-80°: the method of extrapolation of data to an uninvestigated region of the stereographic projection, and the method of "sewing" of partial pole figures measured for three mutually perpendicular plane sections of the product. The limits of applicability of these methods, depending on the shape of the test product and the degree of inhomogeneity of the layer-by-layer texture, were revealed. On the basis of a large number of experimental data, the accuracy of the integral parameters used for calculation of the physical and mechanical properties of metals with a hexagonal crystal structure was found to be equal to 0.02, when taking into account the texture heterogeneity of regular products from Zr-based alloys.

Advanced in In Situ Inspection of Automated Fiber Placement Systems

NASA Technical Reports Server (NTRS)

Juarez, Peter D.; Cramer, K. Elliott; Seebo, Jeffrey P.

2016-01-01

Automated Fiber Placement (AFP) systems have been developed to help take advantage of the tailorability of composite structures in aerospace applications. AFP systems allow the repeatable placement of uncured, spool fed, preimpregnated carbon fiber tape (tows) onto substrates in desired thicknesses and orientations. This automated process can incur defects, such as overlapping tow lines, which can severely undermine the structural integrity of the part. Current defect detection and abatement methods are very labor intensive, and still mostly rely on human manual inspection. Proposed is a thermographic in situ inspection technique which monitors tow placement with an on board thermal camera using the preheated substrate as a through transmission heat source. An investigation of the concept is conducted, and preliminary laboratory results are presented. Also included will be a brief overview of other emerging technologies that tackle the same issue. Keywords: Automated Fiber Placement, Manufacturing defects, Thermography

Laparoscopic access with a visualizing trocar.

PubMed

Wolf, J S

1997-01-01

Although useful in most situations, there are several inherent disadvantages of the standard laparoscopic access techniques of Veress needle insertion and Hasson-type cannula placement. Veress needle placement may be hazardous in patients at high risk for intraabdominal adhesions and difficult in patients who are obese. The usual alternative, the Hasson-type cannula, often does not provide a good gas seal. As another option, the use of a visualizing trocar (OPTIVIEW) has proven to be effective in the initial experience at the University of Michigan. The inner trocar of the visualizing trocar is hollow except for a clear plastic conical tip with two external ridges. The trocar-cannula assembly is passed through tissue layers to enter the operative space under direct vision from a 10-mm zero-degree laparoscope placed into the trocar. Results suggest that this technique is an excellent alternative to Veress needle placement when laparoscopic access is likely to be hazardous or difficult.

Iliac artery angioplasty : technique and results.

PubMed

Brountzos, E N; Kelekis, D A

2004-10-01

Percutaneous angioplasty is widely used for the treatment of iliac artery occlusive disease. Access to the ipsi-lateral, or less commonly contralateral, common femoral artery is obtained under local anaesthesia; the lesion is crossed with a guidewire and dilated with an angioplasty balloon catheter. This technique yields excellent immediate results with very few complications. Stent placement is used in lesions not amenable to balloon angioplasty, in complications, and recurrences. Evidence suggests that balloon angioplasty is the procedure of choice for iliac artery occlusive lesions. Stent placement should be reserved for angioplasty failures. However, primary stent placement is indicated in total occlusions. Lesion morphology is an important determinant of immediate success and long-term patency. TASC lesions type A and B are best treated with angioplasty and stenting, while TASC lesions type C and D show better results with surgical treatment. The development of new stent designs may expand the indications of the percutaneous treatment.

K.s. Micro-implant placement guide.

PubMed

Sharma, K; Sangwan, A

2014-09-01

A one of the greatest concerns with orthodontic mini-implants is risk of injury to dental roots during placement is, especially when they are inserted between teeth. Many techniques have been used to facilitate safe placement of interradicular miniscrews. Brass Wires or metallic markers are easy to place in the interproximal spaces, but because their relative positions may be inconsistent in different radio -graphic views, they are not always accurate. K.S. micro implant placement guide suggested in this article is simple design and easy in fabrication, required minimal equipment for fabrication and does not disturb the existing appliance system, clearly located in the radiograph and the mini-screw can be easily inserted through the guide reducing the chance of implant misplacement.

Optimization in multi-implant placement for immediate loading in edentulous arches using a modified surgical template and prototyping: a case report.

PubMed

Jayme, Sérgio J; Muglia, Valdir A; de Oliveira, Rafael R; Novaes, Arthur B Júnior

2008-01-01

Immediate loading of dental implants shortens the treatment time and makes it possible to give the patient an esthetic appearance throughout the treatment period. Placement of dental implants requires precise planning that accounts for anatomic limitations and restorative goals. Diagnosis can be made with the assistance of computerized tomographic scanning, but transfer of planning to the surgical field is limited. Recently, novel CAD/CAM techniques such as stereolithographic rapid prototyping have been developed to build surgical guides in an attempt to improve precision of implant placement. The aim of this case report was to show a modified surgical template used throughout implant placement as an alternative to a conventional surgical guide.

Pole-zero form fractional model identification in frequency domain

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

Mansouri, R.; Djamah, T.; Djennoune, S.

2009-03-05

This paper deals with system identification in the frequency domain using non integer order models given in the pole-zero form. The usual identification techniques cannot be used in this case because of the non integer orders of differentiation which makes the problem strongly nonlinear. A general identification method based on Levenberg-Marquardt algorithm is developed and allows to estimate the (2n+2m+1) parameters of the model. Its application to identify the ''skin effect'' of a squirrel cage induction machine modeling is then presented.

Ultrasound guided placement of the distal catheter in paediatric ventriculoatrial shunts-an appraisal of efficacy and complications.

PubMed

Clark, David J; Chakraborty, Aabir; Roebuck, Derek J; Thompson, Dominic N P

2016-07-01

Ventriculoatrial (VA) shunts are commonly used as a second-line treatment of hydrocephalus when the peritoneum is an unsuitable site for the distal catheter. Many centres now utilise ultrasound and interventional radiology techniques to aid placement of the distal catheter. The purpose of this study was to conduct a contemporary audit of VA shunting in children using interventional radiology techniques for placement of the distal catheter. A retrospective analysis of all patients who had VA shunts inserted between June 2000 and June 2010 was conducted using a prospectively updated surgical database and case notes review. Ninety-four VA shunts were inserted in 38 patients. Thirty-seven patients had been treated initially with ventriculoperitoneal (VP) shunts. Twenty-two patients required at least 1 shunt revision (58 %). The 6-month, 1- and 2-year shunt survival rates were 53, 43 and 27 %, respectively. Blockage was the commonest reason for shunt failure (68 %). The site of failure was proximal (ventricular catheter +/- valve) in 32 % and distal (atrial catheter) in 21 % of cases. The overall infection rate was 6 % per procedure and 11 % per patient. There were 7 deaths, of which 3 were shunt related. VA shunting provides a viable second-line option for shunt placement in complex hydrocephalus. The causes of shunt failure (blockage, infection and equipment failure) are similar to VP shunting though shunt survival rates are inferior to VP shunts. Ultrasound guided VA shunt placement provides a relatively safe, second-line alternative to the placement of a ventriculoperitoneal shunt when this route is unsuitable.

Stabilization of an inverted pendulum-cart system by fractional PI-state feedback.

PubMed

Bettayeb, M; Boussalem, C; Mansouri, R; Al-Saggaf, U M

2014-03-01

This paper deals with pole placement PI-state feedback controller design to control an integer order system. The fractional aspect of the control law is introduced by a dynamic state feedback as u(t)=K(p)x(t)+K(I)I(α)(x(t)). The closed loop characteristic polynomial is thus fractional for which the roots are complex to calculate. The proposed method allows us to decompose this polynomial into a first order fractional polynomial and an integer order polynomial of order n-1 (n being the order of the integer system). This new stabilization control algorithm is applied for an inverted pendulum-cart test-bed, and the effectiveness and robustness of the proposed control are examined by experiments. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Temperature and melt solid interface control during crystal growth

NASA Technical Reports Server (NTRS)

Batur, Celal

1990-01-01

Findings on the adaptive control of a transparent Bridgman crystal growth furnace are summarized. The task of the process controller is to establish a user specified axial temperature profile by controlling the temperatures in eight heating zones. The furnace controller is built around a computer. Adaptive PID (Proportional Integral Derivative) and Pole Placement control algorithms are applied. The need for adaptive controller stems from the fact that the zone dynamics changes with respect to time. The controller was tested extensively on the Lead Bromide crystal growth. Several different temperature profiles and ampoule's translational rates are tried. The feasibility of solid liquid interface quantification by image processing was determined. The interface is observed by a color video camera and the image data file is processed to determine if the interface is flat, convex or concave.

Existence conditions for unknown input functional observers

NASA Astrophysics Data System (ADS)

Fernando, T.; MacDougall, S.; Sreeram, V.; Trinh, H.

2013-01-01

This article presents necessary and sufficient conditions for the existence and design of an unknown input Functional observer. The existence of the observer can be verified by computing a nullspace of a known matrix and testing some matrix rank conditions. The existence of the observer does not require the satisfaction of the observer matching condition (i.e. Equation (16) in Hou and Muller 1992, 'Design of Observers for Linear Systems with Unknown Inputs', IEEE Transactions on Automatic Control, 37, 871-875), is not limited to estimating scalar functionals and allows for arbitrary pole placement. The proposed observer always exists when a state observer exists for the unknown input system, and furthermore, the proposed observer can exist even in some instances when an unknown input state observer does not exist.

Multiple model self-tuning control for a class of nonlinear systems

NASA Astrophysics Data System (ADS)

Huang, Miao; Wang, Xin; Wang, Zhenlei

2015-10-01

This study develops a novel nonlinear multiple model self-tuning control method for a class of nonlinear discrete-time systems. An increment system model and a modified robust adaptive law are proposed to expand the application range, thus eliminating the assumption that either the nonlinear term of the nonlinear system or its differential term is global-bounded. The nonlinear self-tuning control method can address the situation wherein the nonlinear system is not subject to a globally uniformly asymptotically stable zero dynamics by incorporating the pole-placement scheme. A novel, nonlinear control structure based on this scheme is presented to improve control precision. Stability and convergence can be confirmed when the proposed multiple model self-tuning control method is applied. Furthermore, simulation results demonstrate the effectiveness of the proposed method.

Modelling and control of a microgrid including photovoltaic and wind generation

NASA Astrophysics Data System (ADS)

Hussain, Mohammed Touseef

Extensive increase of distributed generation (DG) penetration and the existence of multiple DG units at distribution level have introduced the notion of micro-grid. This thesis develops a detailed non-linear and small-signal dynamic model of a microgrid that includes PV, wind and conventional small scale generation along with their power electronics interfaces and the filters. The models developed evaluate the amount of generation mix from various DGs for satisfactory steady state operation of the microgrid. In order to understand the interaction of the DGs on microgrid system initially two simpler configurations were considered. The first one consists of microalternator, PV and their electronics, and the second system consists of microalternator and wind system each connected to the power system grid. Nonlinear and linear state space model of each microgrid are developed. Small signal analysis showed that the large participation of PV/wind can drive the microgrid to the brink of unstable region without adequate control. Non-linear simulations are carried out to verify the results obtained through small-signal analysis. The role of the extent of generation mix of a composite microgrid consisting of wind, PV and conventional generation was investigated next. The findings of the smaller systems were verified through nonlinear and small signal modeling. A central supervisory capacitor energy storage controller interfaced through a STATCOM was proposed to monitor and enhance the microgrid operation. The potential of various control inputs to provide additional damping to the system has been evaluated through decomposition techniques. The signals identified to have damping contents were employed to design the supervisory control system. The controller gains were tuned through an optimal pole placement technique. Simulation studies demonstrate that the STATCOM voltage phase angle and PV inverter phase angle were the best inputs for enhanced stability boundaries.

Robot-assisted single port radical nephrectomy and cholecystectomy: description and technical aspects

PubMed Central

Mota, Francisco Hidelbrando Alves; Sávio, Luis Felipe; Sakata, Rafael Eiji; Ivanovic, Renato Fidelis; da Silva, Marco Antonio Nunes; Maia, Ronaldo Soares; Passerotti, Carlo Camargo

2018-01-01

ABSTRACT Introduction Robot-Assisted Single Site Radical Nephrectomy (RASS-RN) has been reported by surgeons in Europe and United States (1–3). To our best knowledge this video presents the first RASS-RN with concomitant cholecystectomy performed in Latin America. Case A 66 year-old renal transplant male due to chronic renal failure presented with an incidental 1.3cm nodule in the upper pole of the right kidney. In addition, symptomatic gallbladder stones were detected. Results Patient was placed in modified flank position. Multichannel single port device was placed using Hassan's technique through a 3 cm supra-umbilical incision. Standard radical nephrectomy and cholecystectomy were made using an 8.5mm camera, two 5mm robotic arms and an assistant 5mm access. Surgery time and estimated blood loss were 208 minutes and 100mL, respectively. Patient did well and was discharged within less than 48 hours, without complications. Pathology report showed benign renomedullary tumor of interstitial cells and chronic cholecystitis. Discussion Robotic technology improves ergonomics, gives better precision and enhances ability to approach complex surgeries. Robot-assisted Single Port aims to reduce the morbidity of multiple trocar placements while maintaining the advantages of robotic surgery (2). Limitations include the use of semi-rigid instruments providing less degree of motion and limited space leading to crash between instruments. On the other hand, it is possible to perform complex and concomitant surgeries with just one incision. Conclusion RASS-RN seems to be safe and feasible option for selected cases. Studies should be performed to better understand the results using single port technique in Urology. PMID:29039889

Robot-assisted single port radical nephrectomy and cholecystectomy: description and technical aspects.

PubMed

Mota Filho, Francisco Hidelbrando Alves; Sávio, Luis Felipe; Sakata, Rafael Eiji; Ivanovic, Renato Fidelis; da Silva, Marco Antonio Nunes; Maia, Ronaldo; Passerotti, Carlo

2018-01-01

Robot-Assisted Single Site Radical Nephrectomy (RASS-RN) has been reported by surgeons in Europe and United States (1-3). To our best knowledge this video presents the first RASS-RN with concomitant cholecystectomy performed in Latin America. A 66 year-old renal transplant male due to chronic renal failure presented with an incidental 1.3cm nodule in the upper pole of the right kidney. In addition, symptomatic gallbladder stones were detected. Patient was placed in modified flank position. Multichannel single port device was placed using Hassan's technique through a 3cm supra-umbilical incision. Standard radical nephrectomy and cholecystectomy were made using na 8.5mm camera, two 5mm robotic arms and an assistant 5mm access. Surgery time and estimated blood loss were 208 minutes and 100mL, respectively. Patient did well and was discharged within less than 48 hours, without complications. Pathology report showed benign renomedullary tumor of interstitial cells and chronic cholecystitis. Robotic technology improves ergonomics, gives better precision and enhances ability to approach complex surgeries. Robot-assisted Single Port aims to reduce the morbidity of multiple trocar placements while maintaining the advantages of robotic surgery (2). Limitations include the use of semi-rigid instruments providing less degree of motion and limited space leading to crash between instruments. On the other hand, it is possible to perform complex and concomitant surgeries with just one incision. RASS-RN seems to be safe and feasible option for selected cases. Studies should be performed to better understand the results using single port technique in Urology. Copyright® by the International Brazilian Journal of Urology.

Robust high-precision attitude control for flexible spacecraft with improved mixed H2/H∞ control strategy under poles assignment constraint

NASA Astrophysics Data System (ADS)

Liu, Chuang; Ye, Dong; Shi, Keke; Sun, Zhaowei

2017-07-01

A novel improved mixed H2/H∞ control technique combined with poles assignment theory is presented to achieve attitude stabilization and vibration suppression simultaneously for flexible spacecraft in this paper. The flexible spacecraft dynamics system is described and transformed into corresponding state space form. Based on linear matrix inequalities (LMIs) scheme and poles assignment theory, the improved mixed H2/H∞ controller does not restrict the equivalence of the two Lyapunov variables involved in H2 and H∞ performance, which can reduce conservatives compared with traditional mixed H2/H∞ controller. Moreover, it can eliminate the coupling of Lyapunov matrix variables and system matrices by introducing slack variable that provides additional degree of freedom. Several simulations are performed to demonstrate the effectiveness and feasibility of the proposed method in this paper.

A Numerical Analysis of Electromagnetic Scattering from Two-Dimensional Edge Terminations

NASA Technical Reports Server (NTRS)

Gray, B. E.; Dominek, A. K.; Wang, N.

1995-01-01

Several techniques that influence the low frequency scattering from penetrable edge terminations are evaluated using a hybrid finite element and boundary element method code. The edge terminations consist of a dielectric skin forming an exterior shape with an internal conducting bulkhead. Some of the techniques considered are bulkhead shaping, internal material loading, placement of resistive cards, and the placement of lossy dielectric material rods. The intent of the various treatments is to find a combination or combinations that influence(s) the backscattered field to acceptable levels over a range of frequencies for both transverse magnetic and transverse electric polarizations.

Ultrasound-Guided Percutaneous Nephrostomy Performed on Neonates and Infants Using a "14-4" (Trocar and Cannula) Technique.

PubMed

Bas, Ahmet; Gülşen, Fatih; Emre, Senol; Samanci, Cesur; Uzunlu, Osman; Cantasdemir, Murat; Emir, Haluk; Numan, Furuzan

2015-12-01

Percutaneous nephrostomy (PCN) catheters are placed under combined ultrasound and fluoroscopic guidance in the interventional radiology suite and present unique challenges in neonates and infants. The purpose of this study was to demonstrate feasibility of PCN using a "14-4" (trocar and cannula) technique on neonates and infants. Between September 2009 and June 2014, data for 27 kidneys from consecutive 22 neonates or infants who underwent PCN catheter placement using the "14-4" technique were retrospectively analyzed. The median age at the time of placement of the PCN catheters was 11 days (range 5-300 days). There were 18 males and 4 females. All procedures were performed in the interventional radiology suite but without using fluoroscopy. Unilateral PCN was performed on 17 out of 22 patients, while bilateral drainage was performed on five patients. The technical success rate was 100%. The median duration of PCN catheter was 75 days (range 10-138 days). Minor macroscopic hematuria not requiring blood transfusion was present in two of the patients in which the hematuria lasted in 2 days. Placement of PCN catheters using a "14-4" technique with ultrasound as the sole imaging modality is a technically feasible and desirable option for neonates or infants. The technique obviates the need for ionizing radiation and potentially could be performed in the ultrasound room or even at the bedside.

Efficacy of the Stonehenge Technique for Minimally Invasive Aortic Valve Replacement via Right Infraaxillary Thoracotomy

PubMed Central

Kin, Hajime; Kitamoto, Shohei; Yamanaka, Shota; Nishida, Hidefumi; Nishigawa, Kosaku; Takanashi, Shuichiro

2017-01-01

Minimally invasive cardiac surgeries for aortic valve replacement (AVR) are still a technical challenge for surgeons because these procedures are undertaken through small incisions and deep surgical fields. Although AVR via vertical infraaxillary thoracotomy can be a cosmetically superior option, a disadvantage of this approach is the distance between the thoracotomy incision and the ascending aorta. Therefore, we devised a technique to perform all manipulations using the fingertips without the aid of a knot pusher or long-shafted surgical instruments. This was achieved by particular placement of several retracted sutures to the right chest wall. We named placement of these sutures the “Stonehenge technique.” In conclusion, AVR via vertical infraaxillary thoracotomy with our Stonehenge technique can be safely and simply performed with superior cosmetic advantages. PMID:28123153

Totally implantable vascular access device (TIVAD) placement: a modified technique that takes post-procedure aesthetic aspects into account.

PubMed

Liberale, Gabriel

2017-04-01

Major progress has been made in breast cancer reconstruction surgery. The standard technique for totally implanted vascular access device (TIVAD) implantation generally requires an incision for port insertion on the anterior part of the thorax that leaves a scar in the middle of the neckline in patients who have undergone mastectomy with complex breast reconstruction. The aim of this technical note is to report our revised surgical technique for TIVAD placement. In patients with breast cancer, we take a lateralized approach, performing an oblique incision on the lowest part of the deltopectoral groove. This allows us to introduce the port and to place it on the anterolateral part of the thorax, thus avoiding an unaesthetic scar on the anterior part of the thorax. Our modified technique for TIVAD implantation is described.

An element search ant colony technique for solving virtual machine placement problem

NASA Astrophysics Data System (ADS)

Srija, J.; Rani John, Rose; Kanaga, Grace Mary, Dr.

2017-09-01

The data centres in the cloud environment play a key role in providing infrastructure for ubiquitous computing, pervasive computing, mobile computing etc. This computing technique tries to utilize the available resources in order to provide services. Hence maintaining the resource utilization without wastage of power consumption has become a challenging task for the researchers. In this paper we propose the direct guidance ant colony system for effective mapping of virtual machines to the physical machine with maximal resource utilization and minimal power consumption. The proposed algorithm has been compared with the existing ant colony approach which is involved in solving virtual machine placement problem and thus the proposed algorithm proves to provide better result than the existing technique.

The surgical learning curve and accuracy of minimally invasive lumbar pedicle screw placement using CT based computer-assisted navigation plus continuous electromyography monitoring - a retrospective review of 627 screws in 150 patients.

PubMed

Wood, Martin James; McMillen, Jason

2014-01-01

This study retrospectively assessed the accuracy of placement of lumbar pedicle screws placed by a single surgeon using a minimally-invasive, intra-operative CT-based computer navigated technique in combination with continuous electromyography (EMG) monitoring. The rates of incorrectly positioned screws were reviewed in the context of the surgeon's experience and learning curve. Data was retrospectively reviewed from all consecutive minimally invasive lumbar fusions performed by the primary author over a period of over 4 years from April 2008 until October 2012. All cases that had utilized computer-assisted intra-operative CT-based image guidance and continuous EMG monitoring to guide percutaneous pedicle screw placement were analysed for the rates of malposition of the pedicle screws. Pedicle screw malposition was defined as having occurred if the screw trajectory was adjusted intraoperatively due to positive EMG responses, or due to breach of the pedicle cortex by more than 2mm on intraoperative CT imaging performed at the end of the instrumentation procedure. Further analysis of the data was undertaken to determine if the rates of malposition changed with the surgeon's experience with the technique. Six hundred and twenty-seven pedicle screws were placed in one hundred and fifty patients. The overall rate of intraoperative malposition and subsequent adjustment of pedicle screw placement was 3.8% (24 of 627 screws). Screw malposition was detected by intraoperative CT imaging. Warning of potential screw misplacement was provided by use of the EMG monitoring. With increased experience with the technique, rates of intraoperative pedicle screw malposition were found to decrease from 5.1% of screws in the first fifty patients, to 2.0% in the last 50 patients. Only one screw was suboptimally placed at the end of surgery, which did not result in a neurological deficit. The use of CT-based computer-assisted navigation in combination with continuous EMG monitoring during percutaneous transpedicular screw placement results in very low rates of malposition and neural injury that compare favourably with previously reported rates. Pedicle screw placement accuracy continues to improve as the surgeon becomes more experienced with the technique.

The surgical learning curve and accuracy of minimally invasive lumbar pedicle screw placement using CT based computer-assisted navigation plus continuous electromyography monitoring – a retrospective review of 627 screws in 150 patients

PubMed Central

McMillen, Jason

2014-01-01

Objective This study retrospectively assessed the accuracy of placement of lumbar pedicle screws placed by a single surgeon using a minimally-invasive, intra-operative CT-based computer navigated technique in combination with continuous electromyography (EMG) monitoring. The rates of incorrectly positioned screws were reviewed in the context of the surgeon's experience and learning curve. Methods Data was retrospectively reviewed from all consecutive minimally invasive lumbar fusions performed by the primary author over a period of over 4 years from April 2008 until October 2012. All cases that had utilized computer-assisted intra-operative CT-based image guidance and continuous EMG monitoring to guide percutaneous pedicle screw placement were analysed for the rates of malposition of the pedicle screws. Pedicle screw malposition was defined as having occurred if the screw trajectory was adjusted intraoperatively due to positive EMG responses, or due to breach of the pedicle cortex by more than 2mm on intraoperative CT imaging performed at the end of the instrumentation procedure. Further analysis of the data was undertaken to determine if the rates of malposition changed with the surgeon's experience with the technique. Results Six hundred and twenty-seven pedicle screws were placed in one hundred and fifty patients. The overall rate of intraoperative malposition and subsequent adjustment of pedicle screw placement was 3.8% (24 of 627 screws). Screw malposition was detected by intraoperative CT imaging. Warning of potential screw misplacement was provided by use of the EMG monitoring. With increased experience with the technique, rates of intraoperative pedicle screw malposition were found to decrease from 5.1% of screws in the first fifty patients, to 2.0% in the last 50 patients. Only one screw was suboptimally placed at the end of surgery, which did not result in a neurological deficit. Conclusion The use of CT-based computer-assisted navigation in combination with continuous EMG monitoring during percutaneous transpedicular screw placement results in very low rates of malposition and neural injury that compare favourably with previously reported rates. Pedicle screw placement accuracy continues to improve as the surgeon becomes more experienced with the technique. PMID:25694919

Universal Parameter Measurement and Sensorless Vector Control of Induction and Permanent Magnet Synchronous Motors

NASA Astrophysics Data System (ADS)

Yamamoto, Shu; Ara, Takahiro

Recently, induction motors (IMs) and permanent-magnet synchronous motors (PMSMs) have been used in various industrial drive systems. The features of the hardware device used for controlling the adjustable-speed drive in these motors are almost identical. Despite this, different techniques are generally used for parameter measurement and speed-sensorless control of these motors. If the same technique can be used for parameter measurement and sensorless control, a highly versatile adjustable-speed-drive system can be realized. In this paper, the authors describe a new universal sensorless control technique for both IMs and PMSMs (including salient pole and nonsalient pole machines). A mathematical model applicable for IMs and PMSMs is discussed. Using this model, the authors derive the proposed universal sensorless vector control algorithm on the basis of estimation of the stator flux linkage vector. All the electrical motor parameters are determined by a unified test procedure. The proposed method is implemented on three test machines. The actual driving test results demonstrate the validity of the proposed method.

Ultrasound-guided Subclavian Vein Cannulation Using a Micro-Convex Ultrasound Probe

PubMed Central

Fair, James; Hirshberg, Eliotte L.; Grissom, Colin K.; Brown, Samuel M.

2014-01-01

Background: The subclavian vein is the preferred site for central venous catheter placement due to infection risk and patient comfort. Ultrasound guidance is useful in cannulation of other veins, but for the subclavian vein, current ultrasound-guided techniques using high-frequency linear array probes are generally limited to axillary vein cannulation. Methods: We report a series of patients who underwent clinically indicated subclavian venous catheter placement using a micro-convex pediatric probe for real-time guidance in the vein’s longitudinal axis. We identified rates of successful placement and complications by chart review. Results: Twenty-four catheters were placed using the micro-convex pediatric probe with confirmation of placement of the needle medial to the lateral border of the first rib. Sixteen of the catheters were placed by trainee physicians. In 23 patients, the catheter was placed without complication (hematoma, pneumothorax, infection). In one patient, the vein could not be safely cannulated without risk of arterial puncture, so an alternative site was selected. Conclusions: Infraclavicular subclavian vein cannulation using real-time ultrasound with a micro-convex pediatric probe appears to be a safe and effective method of placing subclavian vascular catheters. This technique merits further study to confirm safety and efficacy. PMID:24611628

Laparoscopy in patients following transverse rectus abdominis myocutaneous flap reconstruction.

PubMed

Muller, C Y; Coleman, R L; Adams, W P

2000-07-01

We report our technique and experience performing laparoscopic pelvic surgery on four women after transverse abdominus rectus myocutaneous flap (TRAM). Examination under anesthesia is performed on all patients in the low lithotomy position parallel with the floor. The abdominal aorta is palpated and outlined. A pneumoperitoneum is created either by umbilical or left upper quadrant Veress placement. Patients with an acceptable umbilical location undergo port placement through the incision of the umbilical relocation. Other options include left upper quadrant or paramedian placement avoiding the ligamentum teres vessels. Lateral operative ports (5 mm) are placed with reference to the transverse incision present, the pelvic pathology, and the location of the umbilicus. Techniques of electrocautery, intra- and extracorporeal suturing and knot tying, and clips are preferred to minimize port size. Following unilateral or bilateral TRAM reconstruction, four consecutive breast cancer survivors underwent successful laparoscopic-assisted vaginal hysterectomy with oophorectomy using the periumbilical incision for trocar placement. The only complication was a superficial skin breakdown from an adhesive allergy that required 6 weeks for complete resolution. Laparoscopic pelvic surgery is feasible in women after TRAM reconstruction. Knowledge of anatomic and physiologic variations related to the TRAM procedure is necessary in planning a safe operation.

Mars Orbiter Sample Return Power Design

NASA Technical Reports Server (NTRS)

Mardesich, N.; Dawson, S.

1999-01-01

The NASA/JPL 2003/2005 Mars Sample Return (MSR) Missions will each have a sample return canister that will be filled with samples cored from the surface of MARS. These spherical canisters will be 14.8 cm in diameter and must be powered only by solar cells on the surface and must communicate using RF transmission with the recovery vehicle that will be coming in 2006 or 2009 to retrieve the canister. This paper considers the aspect and conclusion that went into the design of the power system that achieves the maximum power with the minimum risk. The power output for the spherical orbiting canister was modeled and plotted in various views of the orbit by the SOAP program developed by JPL. The requirements and geometry for a solar array on a sphere are unique and place special constraints on the design. These requirements include 1) accommodating a lid for sample loading into the canister, surface area was restricted from use on the Northern pole of the spherical canister. 2) minimal cell surface coverage (maximum cell efficiency), less than 40%, for recovery vehicle to locate the canister by optical techniques. 3) a RF transmission during 50% of MARS orbit time on any spin axis, which requires optimum circuit placement of the solar cell onto the spherical canister. The best configuration would have been a 4.5 volt round cell, but in the real world we compromised with six triangular silicon cells connected in series to form a hexagon. These hexagon circuits would be mounted onto a flat facet cut into the spherical canister. The surface flats are required in order to maximize power, the surface of the cells connected in series must be at the same angle relative to the sun. The flat facets intersect each other to allow twelve circuits evenly spaced just North and twelve circuits South of the equator of the spherical canister. Connecting these circuits in parallel allows sufficient power to operate the transmitter at minimum solar exposure, Northern pole of the canister facing the sun. Additional power, as much as 20%, is also generated by the circuits facing MARS due to albedo of MARS.

The difficult ureter: what is the incidence of pre-stenting?

PubMed Central

Cetti, RJ; Biers, S; Keoghane, SR

2010-01-01

INTRODUCTION Difficulty may be encountered with retrograde access for rigid and flexible ureterorenoscopy (URS) due to anatomic abnormalities, a narrow ureteric lumen, tortuous ureteric path or previous instrumentation. Ureteric dilatation using a balloon or tapered dilator can occasionally fail and will usually lead to the placement of a ureteric stent. We present our experience and incidence of pre-stenting after failed standard access and dilatation techniques, the aim being to quote a figure for the patient at the time of consent. PATIENTS AND METHODS Data were collected prospectively from a single surgeon at a regional tertiary referral stone unit. The outcomes of those patients pre-stented, for failed access, were recorded. RESULTS Between December 2007 and December 2008, a total of 119 patients underwent flexible and rigid URS. Mean patient age was 49 years (range, 19–86 years). Of these, 107 cases were undertaken for urolithiasis and 12 cases for diagnosis of upper tract malignancy. 12% (13/107) of cases were for pain and non-diagnostic imaging and 8.4% (9/107) of patients were pre-stented because of failed access, without complication, and subsequently had successful interval treatment. Of the remaining successful cases of confirmed urolithiasis, 33% (28/85) and 67% (56/85) were undertaken for ureteric and renal calculi, respectively. Stone clearance rates were 83% (19/23) and 75% (3/4) for lower pole renal calculi 5–10 mm and > 10 mm in size, respectively. The overall clearance rate for lower pole calculi was 81% (22/27). The ureteric stone clearance rate was 86% (24/28) rising to 92% (24/26) in those solitary stones less than 10 mm in size. CONCLUSIONS The incidence of ureteric pre-stenting in a tertiary referral unit was 8% and should be considered and indeed discussed with patients when obtaining pre-operative consent, especially for purely elective, non-urgent, upper tract cases. The alternative for these difficult, tight ureters is extensive balloon dilatation, with the risk of trauma and the potential for long-term stricture formation. PMID:20937199

A genetic algorithm for replica server placement

NASA Astrophysics Data System (ADS)

Eslami, Ghazaleh; Toroghi Haghighat, Abolfazl

2012-01-01

Modern distribution systems use replication to improve communication delay experienced by their clients. Some techniques have been developed for web server replica placement. One of the previous studies was Greedy algorithm proposed by Qiu et al, that needs knowledge about network topology. In This paper, first we introduce a genetic algorithm for web server replica placement. Second, we compare our algorithm with Greedy algorithm proposed by Qiu et al, and Optimum algorithm. We found that our approach can achieve better results than Greedy algorithm proposed by Qiu et al but it's computational time is more than Greedy algorithm.

A genetic algorithm for replica server placement

NASA Astrophysics Data System (ADS)

Eslami, Ghazaleh; Toroghi Haghighat, Abolfazl

2011-12-01

Modern distribution systems use replication to improve communication delay experienced by their clients. Some techniques have been developed for web server replica placement. One of the previous studies was Greedy algorithm proposed by Qiu et al, that needs knowledge about network topology. In This paper, first we introduce a genetic algorithm for web server replica placement. Second, we compare our algorithm with Greedy algorithm proposed by Qiu et al, and Optimum algorithm. We found that our approach can achieve better results than Greedy algorithm proposed by Qiu et al but it's computational time is more than Greedy algorithm.

Conservative mastectomies and immediate reconstruction with the use of ADMs.

PubMed

Govshievich, Alexander; Somogyi, Ron B; Brown, Mitchell H

2015-12-01

In recent years, a novel approach to immediate breast reconstruction has been introduced with the advent of acellular dermal matrix (ADM). In the setting of conservative mastectomies where the native skin envelope is preserved, placement of ADM at the lower pole in continuity with the pectoralis major muscle (PMM) provides additional support, allowing direct-to-implant breast reconstruction. The following manuscript presents the senior author's experience with ADM-assisted reconstruction and provides a detailed description of surgical technique along with a comprehensive discussion of patient selection and potential complications. A retrospective chart review of patients undergoing direct-to-implant breast reconstruction following skin sparing or nipple sparing mastectomy with the use of ADM (AlloDerm; LifeCell Corp., Branchburg, USA) was conducted at Women's College Hospital in Toronto over a 5-year period [2008-2013]. Demographic data, previous radiation therapy and post-operative complications were recorded. A total of 72 patients representing 119 breasts were identified. Average follow-up was 16 months (range, 3-51 months). Twenty-seven complications were recorded for a complication rate of 22.7% (27/119). Complications included six cases of capsular contracture (Baker III/IV), five cases of red skin syndrome, four cases of rippling, three cases of dehiscence and two cases of seroma. Overall, direct-to-implant reconstruction was successfully completed in 97.5% of breasts (116/119). One case of infection was treated with explantation and conversion to autogenous reconstruction. Two breasts with tissue necrosis or dehiscence had the implants removed and replaced with tissue expanders. Overall reoperation rate was 9.7% (7/72 patients). ADM assisted direct-to-implant breast reconstruction has been shown to be a safe option for women who are candidates for skin sparing or nipple sparing mastectomies. Judicious patient selection, effective collaboration between the oncologic and reconstructive surgeon, careful evaluation of post-mastectomy skin flaps and precise surgical technique are paramount to the success of this technique.

Open flap versus flapless placement of dental implants. A randomized controlled pilot trial.

PubMed

Jané-Salas, Enric; Roselló-LLabrés, Xavier; Jané-Pallí, Enric; Mishra, Siddharth; Ayuso-Montero, Raúl; López-López, José

2018-02-20

The aim of this study was to compare the immediate postoperative period of participants rehabilitated with dental implants placed with a conventional technique or with a minimally invasive technique, without a mucoperiosteal flap elevation (flapless). Participants who needed implant placement were divided into two groups: one group was operated using a mucoperiosteal flap elevation (G_A), and the other with a flapless surgical technique (G_B). Objective clinical parameters including oral hygiene, mouth opening, inflammation (facial perimeter), surgical time and analgesic consumption, as well as subjective parameters of pain and degree of satisfaction with the procedure, were evaluated. 48 implants were placed in 30 participants (15 participants per group). Oral hygiene index, maximum interincisal opening, pain and analgesic consumption values had a significant difference between groups favoring the flapless technique at 24 h and 7 days but at the 15 days' follow-up the differences were only significant for oral hygiene and pain (P < 0.05); there were no statistically significant differences between groups in terms of facial perimeter values and surgical time (P > 0.05). Average on the degree of satisfaction was of 2.6 (SD 0.8) for G_A and 3.6 (SD 1.02) for G_B (P = 0.06). One implant placed in G_A (2.0%) failed before prosthetic loading due to mobility and pain at 3 months' follow-up. Participants operated for implant placement with flapless surgical technique go through less postoperative discomfort. Both techniques show high success rates, but to perform a flapless technique patients must be properly selected.

RBT-GA: a novel metaheuristic for solving the Multiple Sequence Alignment problem.

PubMed

Taheri, Javid; Zomaya, Albert Y

2009-07-07

Multiple Sequence Alignment (MSA) has always been an active area of research in Bioinformatics. MSA is mainly focused on discovering biologically meaningful relationships among different sequences or proteins in order to investigate the underlying main characteristics/functions. This information is also used to generate phylogenetic trees. This paper presents a novel approach, namely RBT-GA, to solve the MSA problem using a hybrid solution methodology combining the Rubber Band Technique (RBT) and the Genetic Algorithm (GA) metaheuristic. RBT is inspired by the behavior of an elastic Rubber Band (RB) on a plate with several poles, which is analogues to locations in the input sequences that could potentially be biologically related. A GA attempts to mimic the evolutionary processes of life in order to locate optimal solutions in an often very complex landscape. RBT-GA is a population based optimization algorithm designed to find the optimal alignment for a set of input protein sequences. In this novel technique, each alignment answer is modeled as a chromosome consisting of several poles in the RBT framework. These poles resemble locations in the input sequences that are most likely to be correlated and/or biologically related. A GA-based optimization process improves these chromosomes gradually yielding a set of mostly optimal answers for the MSA problem. RBT-GA is tested with one of the well-known benchmarks suites (BALiBASE 2.0) in this area. The obtained results show that the superiority of the proposed technique even in the case of formidable sequences.

Single-stick tunneled central venous access using the jugular veins in infants weighing less than 5 kg.

PubMed

Lindquester, Will S; Hawkins, C Matthew; Monroe, Eric J; Gill, Anne E; Shivaram, Giridhar M; Seidel, F Glen; Lungren, Matthew P

2017-11-01

Despite the demonstrated feasibility of the single-stick technique in the femoral vein, its use in neonates and infants for placing central lines in internal and external jugular veins has not been reported. Describe and assess the safety and efficacy of tunneled jugular central venous catheter placement performed under ultrasound (US) and fluoroscopic guidance in neonates and infants weighing <5 kg using the single-stick technique at three tertiary pediatric hospitals. Thirty-three children weighing less than 5 kg received tunneled central venous access in either internal or external jugular veins using the single-stick technique. Patient history, procedural records and clinical follow-up documents were retrospectively reviewed. Complication rates were compared to those of 41 patients receiving single-stick femoral central lines. Technical complications occurred during one (3.0%) jugular placement with the patient having a failed right-side attempt with subsequent successful left-side placement. The catheters did not last the entire course of treatment in three (9.1%) patients with jugular lines. One patient had the catheter removed due to concern for infection, one catheter was accidentally removed during dressing changes, and one catheter was displaced and subsequently exchanged. Of patients receiving femoral central lines, 1 (2.4%) had a technical complication and 5 catheters (12.2%) did not last the entire course of treatment. The placement of tunneled central venous catheters in neonates/infants <5 kg is safe and technically feasible using the internal/external jugular vein via the single-stick technique. By theoretically reducing the risks of catheter infection by avoiding the diaper area and thrombosis by using larger veins, it may be preferable in certain patient populations.

Surgical Navigation Technology Based on Augmented Reality and Integrated 3D Intraoperative Imaging: A Spine Cadaveric Feasibility and Accuracy Study.

PubMed

Elmi-Terander, Adrian; Skulason, Halldor; Söderman, Michael; Racadio, John; Homan, Robert; Babic, Drazenko; van der Vaart, Nijs; Nachabe, Rami

2016-11-01

A cadaveric laboratory study. The aim of this study was to assess the feasibility and accuracy of thoracic pedicle screw placement using augmented reality surgical navigation (ARSN). Recent advances in spinal navigation have shown improved accuracy in lumbosacral pedicle screw placement but limited benefits in the thoracic spine. 3D intraoperative imaging and instrument navigation may allow improved accuracy in pedicle screw placement, without the use of x-ray fluoroscopy, and thus opens the route to image-guided minimally invasive therapy in the thoracic spine. ARSN encompasses a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D capabilities, integrated optical cameras for augmented reality navigation, and noninvasive patient motion tracking. Two neurosurgeons placed 94 pedicle screws in the thoracic spine of four cadavers using ARSN on one side of the spine (47 screws) and free-hand technique on the contralateral side. X-ray fluoroscopy was not used for either technique. Four independent reviewers assessed the postoperative scans, using the Gertzbein grading. Morphometric measurements of the pedicles axial and sagittal widths and angles, as well as the vertebrae axial and sagittal rotations were performed to identify risk factors for breaches. ARSN was feasible and superior to free-hand technique with respect to overall accuracy (85% vs. 64%, P < 0.05), specifically significant increases of perfectly placed screws (51% vs. 30%, P < 0.05) and reductions in breaches beyond 4 mm (2% vs. 25%, P < 0.05). All morphometric dimensions, except for vertebral body axial rotation, were risk factors for larger breaches when performed with the free-hand method. ARSN without fluoroscopy was feasible and demonstrated higher accuracy than free-hand technique for thoracic pedicle screw placement. N/A.

Shunting for hydrocephalus: analysis of techniques and failure patterns.

PubMed

Nigim, Fares; Critchlow, Jonathan F; Schneider, Benjamin E; Chen, Clark; Kasper, Ekkehard M

2014-09-01

Hydrocephalus is characterized by ventricular dilatation because of progressive accumulation of cerebrospinal fluid. Normal pressure hydrocephalus (NPH) affects a subset of patients representing a reversible clinical triad of gait disturbance, urinary incontinence, and dementia with normal cerebrospinal fluid pressure and composition. Various shunting procedures have been used for treatment, but techniques and outcomes remain under debate. The objective of this study was to evaluate the clinical outcomes of 232 patients with and without NPH after the first-time Ventriculoperitoneal shunt placement and assessed patterns of failure between December 2004 and December 2012. Mean age was 54.7 y in non-NPH and 71.9 y in NPH patients. We used open technique in 34.3% and laparoscopic technique in 65.7% of NPH patients and 32.7% and 67.3% of the non-NPH patients, respectively. A total of 36 of 232 patients displayed shunt failure, 16.4% in NPH and 15.2% in non-NPH patients. Twenty-three of 155 patients failed after laparoscopic and 13 of 77 failed after open placement. Proximal shunt failure was more frequent in the non-NPH cohort. Distal failures accounted for 13 of 232 cases, and the difference between laparoscopic (six of 155) and open failures (seven of 77) was profound, but not between NPH- and non-NPH patients. Shunt failures are related to the placement method. Non-NPH patients showed more proximal failures. NPH patients showed fewer proximal failures. Less distal failures were observed after laparoscopic ventriculoperitoneal shunt placement without significant differences between NPH and non-NPH patients. Beyond this, laparoscopic surgery carries distinct advantages such as shorter operating room times and hospital stays, which should translate into less use of pain medications, earlier mobilization, and a lower incidence of ileus. Copyright © 2014 Elsevier Inc. All rights reserved.

Immediate placement and provisionalization of maxillary anterior single implant with guided bone regeneration, connective tissue graft, and coronally positioned flap procedures.

PubMed

Waki, Tomonori; Kan, Joseph Y K

2016-01-01

Immediate implant placement and provisionalization in the esthetic zone have been documented with success. The benefit of immediate implant placement and provisionalization is the preservation of papillary mucosa. However, in cases with osseous defects presenting on the facial bony plate, immediate implant placement procedures have resulted in facial gingival recession. Subepithelial connective tissue grafts for immediate implant placement and provisionalization procedures have been reported with a good esthetic outcome. Biotype conversion around implants with subepithelial connective tissue grafts have been advocated, and the resulting tissues appear to be more resistant to recession. The dimensions of peri-implant mucosa in a thick biotype were significantly greater than in a thin biotype. Connective tissue graft with coronally positioned flap procedures on natural teeth has also been documented with success. This article describes a technique combining immediate implant placement, provisionalization, guided bone regeneration (GBR), connective tissue graft, and a coronally positioned flap in order to achieve more stable peri-implant tissue in facial osseous defect situations.

Single-staged vs. two-staged implant placement using bone ring technique in vertically deficient alveolar ridges - Part 1: histomorphometric and micro-CT analysis.

PubMed

Nakahara, Ken; Haga-Tsujimura, Maiko; Sawada, Kosaku; Kobayashi, Eizaburo; Mottini, Matthias; Schaller, Benoit; Saulacic, Nikola

2016-11-01

Simultaneous implant placement with bone grafting shortens the overall treatment period, but might lead to the peri-implant bone loss or even implant failure. The aim of this study was to compare the single-staged to two-staged implant placement using the bone ring technique. Four standardized alveolar bone defects were made in the mandibles of nine dogs. Dental implants (Straumann BL ® , Basel, Switzerland) were inserted simultaneously with bone ring technique in test group and after 6 months of healing period in control group. Animals of both groups were euthanized at 3 and 6 months of osseointegration period. The harvested samples were analyzed by means of histology and micro-CT. The amount of residual bone decreased while the amount of new bone increased up to 9 months of healing period. All morphometric parameters remained stable between 3 and 6 months of osseointegration period within groups. Per a given time point, median area of residual bone graft was higher in test group and area of new bone in control group. The volume of bone ring was greater in test than in control group, reaching the significance at 6 months of osseointegration period (P = 0.002). In the present type of bone defect, single-staged implant placement may be potentially useful to shorten an overall treatment period. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Electromagnetic navigation technology for more precise electrode placement in the foramen ovale: a technical report.

PubMed

Van Buyten, Jean-Pierre; Smet, Iris; Van de Kelft, Erik

2009-07-01

Introduction. Interventional pain management techniques require precise positioning of needles or electrodes, therefore fluoroscopic control is mandatory. This imaging technique does however not visualize soft tissues such as blood vessels. Moreover, patient and physician are exposed to a considerable dose of radiation. Computed tomography (CT)-scans give a better view of soft tissues, but there use requires presence of a radiologist and has proven to be laborious and time consuming. Objectives. This study is to develop a technique using electromagnetic (EM) navigation as a guidance technique for interventional pain management, using CT and/or magnetic resonance (MRI) images uploaded on the navigation station. Methods. One of the best documented interventional procedures for the management of trigeminal neuralgia is percutaneous radiofrequency treatment of the Gasserian ganglion. EM navigation software for intracranial applications already exists. We developed a technique using a stylet with two magnetic coils suitable for EM navigation. The procedure is followed in real time on a computer screen where the patient's multislice CT-scan images and three-dimensional reconstruction of his face are uploaded. Virtual landmarks on the screen are matched with those on the patient's face, calculating the precision of the needle placement. Discussion. The experience with EM navigation acquired with the radiofrequency technique can be transferred to other interventional pain management techniques, for instance, for the placement of a neuromodulation electrode close to the Gasserian ganglion. Currently, research is ongoing to extend the software of the navigation station for spinal application, and to adapt neurostimulation hardware to the EM navigation technology. This technology will allow neuromodulation techniques to be performed without x-ray exposure for the patient and the physician, and this with the precision of CT/MR imaging guidance. © 2009 International Neuromodulation Society.

Reductive Augmentation of the Breast.

PubMed

Chasan, Paul E

2018-06-01

Although breast reduction surgery plays an invaluable role in the correction of macromastia, it almost always results in a breast lacking in upper pole fullness and/or roundness. We present a technique of breast reduction combined with augmentation termed "reductive augmentation" to solve this problem. The technique is also extremely useful for correcting breast asymmetry, as well as revising significant pseudoptosis in the patient who has previously undergone breast augmentation with or without mastopexy. An evolution of techniques has been used to create a breast with more upper pole fullness and anterior projection in those patients desiring a more round, higher-profile appearance. Reductive augmentation is a one-stage procedure in which a breast augmentation is immediately followed by a modified superomedial pedicle breast reduction. Often, the excision of breast tissue is greater than would normally be performed with breast reduction alone. Thirty-five patients underwent reductive augmentation, of which 12 were primary surgeries and 23 were revisions. There was an average tissue removal of 255 and 227 g, respectively, per breast for the primary and revision groups. Six of the reductive augmentations were performed for gross asymmetry. Fourteen patients had a previous mastopexy, and 3 patients had a previous breast reduction. The average follow-up was 26 months. Reductive augmentation is an effective one-stage method for achieving a more round-appearing breast with upper pole fullness both in primary breast reduction candidates and in revisionary breast surgery. This technique can also be applied to those patients with significant asymmetry. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The orbits of the uranian satellites and rings, the gravity field of the uranian system, and the orientation of the pole of Uranus

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

Jacobson, R. A., E-mail: robert.jacobson@jpl.nasa.gov

2014-11-01

French et al. determined the orbits of the Uranian rings, the orientation of the pole of Uranus, and the gravity harmonics of Uranus from Earth-based and Voyager ring occultations. Jacobson et al. determined the orbits of the Uranian satellites and the masses of Uranus and its satellites from Earth-based astrometry and observations acquired with the Voyager 2 spacecraft; they used the gravity harmonics and pole from French et al. Jacobson and Rush reconstructed the Voyager 2 trajectory and redetermined the Uranian system gravity parameters, satellite orbits, and ring orbits in a combined analysis of the data used previously augmented withmore » additional Earth-based astrometry. Here we report on an extension of that work that incorporates additional astrometry and ring occultations together with improved data processing techniques.« less

Strategic Placement of Treatments (SPOTS): Maximizing the Effectiveness of Fuel and Vegetation Treatments on Problem Fire Behavior and Effects

Treesearch

Diane M. Gercke; Susan A. Stewart

2006-01-01

In 2005, eight U.S. Forest Service and Bureau of Land Management interdisciplinary teams participated in a test of strategic placement of treatments (SPOTS) techniques to maximize the effectiveness of fuel treatments in reducing problem fire behavior, adverse fire effects, and suppression costs. This interagency approach to standardizing the assessment of risks and...

Bedside inferior vena cava filter placement by intravascular ultrasound in critically ill patients is safe and effective for an extended time.

PubMed

Glocker, Roan J; Awonuga, Oluwafunmi; Novak, Zdenek; Pearce, Benjamin J; Patterson, Mark; Matthews, Thomas C; Jordan, William D; Passman, Marc A

2014-10-01

Bedside inferior vena cava filter (IVCF) placement by intravascular ultrasound (IVUS) guidance has previously been shown to be a safe and effective technique, especially for critically ill patients, with initial experience of a prospectively implemented algorithm. The purpose of this study was to evaluate the effectiveness of IVUS-guided filter placement in critically ill patients with experience now extending out 5 years from implementation. All patients undergoing bedside IVUS-guided IVCF placement from 2008 to 2012 were identified. Records were reviewed on the basis of IVCF reporting standards. Outcomes data including technical success, complications, and mortality were analyzed at 30 days. During the 5-year period, 398 patients underwent attempted bedside IVCF placement by IVUS. Technical feasibility was possible in 396 cases (99.5%); two bedside procedures were aborted because of inadequate IVUS visualization. Overall technical success was achieved in 393 of 396 (99.2%), with malpositioned IVCF in three cases. An optional IVCF was used in 372 (93.9%) and a permanent IVCF in 24 (6.1%). Single-puncture technique was performed in 388 (97.4%); additional dual access was required in 10 (2.6%). Periprocedural complications were rare (3.0%) and included malpositioning that required retrieval and repositioning or an additional IVCF (3), filter tilt ≥20 degrees (4), arteriovenous fistulas (2), insertion site thrombosis (2), and hematoma (1). Comparison of the first 100 procedures performed within the sample population with the last 100 procedures revealed an overall success rate of 96% in the first 100 compared with 100% in the last 100 (P = .043). There were no deaths related to pulmonary embolism or IVCF-related problems. On the basis of 5 years of experience with bedside IVCF placement in critically ill patients, the IVUS-guided IVCF technique continues to be a safe and effective option in this high-risk population, with a time-dependent improvement in outcome measures. Copyright © 2014 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Image-guided optimization of the ECG trace in cardiac MRI.

PubMed

Barnwell, James D; Klein, J Larry; Stallings, Cliff; Sturm, Amanda; Gillespie, Michael; Fine, Jason; Hyslop, W Brian

2012-03-01

Improper electrocardiogram (ECG) lead placement resulting in suboptimal gating may lead to reduced image quality in cardiac magnetic resonance imaging (CMR). A patientspecific systematic technique for rapid optimization of lead placement may improve CMR image quality. A rapid 3 dimensional image of the thorax was used to guide the realignment of ECG leads relative to the cardiac axis of the patient in forty consecutive adult patients. Using our novel approach and consensus reading of pre- and post-correction ECG traces, seventy-three percent of patients had a qualitative improvement in their ECG tracings, and no patient had a decrease in quality of their ECG tracing following the correction technique. Statistically significant improvement was observed independent of gender, body mass index, and cardiac rhythm. This technique provides an efficient option to improve the quality of the ECG tracing in patients who have a poor quality ECG with standard techniques.

Prospective implementation of an algorithm for bedside intravascular ultrasound-guided filter placement in critically ill patients.

PubMed

Killingsworth, Christopher D; Taylor, Steven M; Patterson, Mark A; Weinberg, Jordan A; McGwin, Gerald; Melton, Sherry M; Reiff, Donald A; Kerby, Jeffrey D; Rue, Loring W; Jordan, William D; Passman, Marc A

2010-05-01

Although contrast venography is the standard imaging method for inferior vena cava (IVC) filter insertion, intravascular ultrasound (IVUS) imaging is a safe and effective option that allows for bedside filter placement and is especially advantageous for immobilized critically ill patients by limiting resource use, risk of transportation, and cost. This study reviewed the effectiveness of a prospectively implemented algorithm for IVUS-guided IVC filter placement in this high-risk population. Current evidence-based guidelines were used to create a clinical decision algorithm for IVUS-guided IVC filter placement in critically ill patients. After a defined lead-in phase to allow dissemination of techniques, the algorithm was prospectively implemented on January 1, 2008. Data were collected for 1 year using accepted reporting standards and a quality assurance review performed based on intent-to-treat at 6, 12, and 18 months. As defined in the prospectively implemented algorithm, 109 patients met criteria for IVUS-directed bedside IVC filter placement. Technical feasibility was 98.1%. Only 2 patients had inadequate IVUS visualization for bedside filter placement and required subsequent placement in the endovascular suite. Technical success, defined as proper deployment in an infrarenal position, was achieved in 104 of the remaining 107 patients (97.2%). The filter was permanent in 21 (19.6%) and retrievable in 86 (80.3%). The single-puncture technique was used in 101 (94.4%), with additional dual access required in 6 (5.6%). Periprocedural complications were rare but included malpositioning requiring retrieval and repositioning in three patients, filter tilt >/=15 degrees in two, and arteriovenous fistula in one. The 30-day mortality rate for the bedside group was 5.5%, with no filter-related deaths. Successful placement of IVC filters using IVUS-guided imaging at the bedside in critically ill patients can be established through an evidence-based prospectively implemented algorithm, thereby limiting the need for transport in this high-risk population. Copyright (c) 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Meromorphic solutions of recurrence relations and DRA method for multicomponent master integrals

NASA Astrophysics Data System (ADS)

Lee, Roman N.; Mingulov, Kirill T.

2018-04-01

We formulate a method to find the meromorphic solutions of higher-order recurrence relations in the form of the sum over poles with coefficients defined recursively. Several explicit examples of the application of this technique are given. The main advantage of the described approach is that the analytical properties of the solutions are very clear (the position of poles is explicit, the behavior at infinity can be easily determined). These are exactly the properties that are required for the application of the multiloop calculation method based on dimensional recurrence relations and analyticity (the DRA method).

Soft Tissue Grafting Around Teeth and Implants.

PubMed

Deeb, George R; Deeb, Janina Golob

2015-08-01

The presence of healthy attached tissue at the tooth and implant soft tissue interface correlates with long-term success and stability in function and esthetics. There are several soft tissue grafting procedures that increase the volume of keratinized tissue and provide coverage on both teeth and implants. Many of these techniques can be used in conjunction with implant placement, or after placement as a means of salvage. This article describes the techniques for augmentation of keratinized tissue as well as root and implant coverage. These tools should be in the armamentarium of oral and maxillofacial surgeons providing implant services. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel method for stereotactic, endoscope-assisted transtentorial placement of a shunt catheter into symptomatic posterior fossa cysts.

PubMed

Turner, Michael S; Nguyen, Ha Son; Payner, Troy D; Cohen-Gadol, Aaron A

2011-07-01

Posterior fossa cysts are usually divided into Dandy-Walker malformations, arachnoid cysts, and isolated and/or trapped fourth ventricles. Shunt placement is a mainstay treatment for decompression of these fluid collections when their expansion becomes symptomatic. Although several techniques to drain symptomatic posterior fossa cysts have been described, each method carries its own advantages and disadvantages. This article describes an alternative technique. In 10 patients, the authors used an alternative technique involving stereotactic and endoscopic methods to place a catheter in symptomatic posterior fossa cysts across the tentorium. Discussion of these cases is included, along with a review of various approaches to shunt placement in this region and recommendations regarding the proposed technique. No patient suffered intracranial hemorrhage related to the procedure and catheter implantation. All 3 patients who underwent placement of a new transtentorial cystoperitoneal shunt and a new ventriculoperitoneal shunt did not suffer any postoperative complication; a decrease in the size of their posterior fossa cysts was evident on CT scans obtained during the 1st postoperative day. Follow-up CT scans demonstrated either stable findings or further interval decrease in the size of their cysts. In 1 patient, the postoperative head CT demonstrated that the transtentorial catheter terminated posterior to the right parietal occipital region without entering the retrocerebellar cyst. This patient underwent a repeat operation for proximal shunt revision, resulting in an acceptable catheter implantation. The patient in Case 8 suffered from a shunt infection and subsequently underwent hardware removal and aqueductoplasty with stent placement. The patient in Case 9 demonstrated a slight increase in fourth ventricle size and was returned to the operating room. Exploration revealed a kink in the tubing connecting the distal limb of the Y connector to the valve. The Y connector was replaced with a T connector, and 1 week later, CT scans exhibited interval decompression of the ventricles. This patient later presented with cranial wound breakdown and an exposed shunt. His shunt hardware was removed and he was treated with antibiotics. He later underwent reimplantation of a lateral ventricular and transtentorial shunt and suffered no other complications during a 3-year follow-up period. The introduction of endoscopic and stereotactic techniques has expanded the available treatment possibilities for posterior fossa cysts.

Heat generation during implant placement in low-density bone: effect of surgical technique, insertion torque and implant macro design.

PubMed

Marković, Aleksa; Mišić, Tijana; Miličić, Biljana; Calvo-Guirado, Jose Luis; Aleksić, Zoran; Ðinić, Ana

2013-07-01

The study aimed to investigate the effect of surgical technique, implant macrodesign and insertion torque on bone temperature changes during implant placement. In the in vitro study, 144 self-tapping (blueSKY(®) 4 × 10 mm; Bredent) and 144 non-self-tapping (Standard implant(®) 4.1 × 10 mm; Straumann) were placed in osteotomies prepared in pig ribs by lateral bone condensing or bone drilling techniques. The maximum insertion torque values of 30, 35 and 40 Ncm were used. Real-time bone temperature measurement during implant placement was performed by three thermocouples positioned vertically, in tripod configuration around every osteotomy, at a distance of 5 mm from it and at depths of 1, 5 and 10 mm. Data were analysed using Kruskal-Wallis, Mann-Whitney U-tests and Regression analysis. Significant predictor of bone temperature at the osteotomy depth of 1 mm was insertion torque (P = 0.003) and at the depth of 10-mm implant macrodesign (P = 0.029), while no significant predictor at depth of 5 mm was identified (P > 0.05). Higher insertion torque values as well as non-self-tapping implant macrodesign were related to higher temperatures. Implant placement in sites prepared by bone drilling induced significantly higher temperature increase (P = 0.021) compared with bone condensing sites at the depth of 5 mm, while no significant difference was recorded at other depths. Compared with 30 Ncm, insertion torque values of 35 and 40 Ncm produced significantly higher temperature increase (P = 0.005; P = 0.003, respectively) at the depth of 1 mm. There was no significant difference in temperature change induced by 35 and 40 Ncm, neither by implant macrodesign at all investigated depths (P > 0.05). Placement of self-tapping implants with low insertion torque into sites prepared by lateral bone condensing technique might be advantageous in terms of thermal effect on bone. © 2012 John Wiley & Sons A/S.

Stainless Steel Crown Placement Utilizing the Hall Technique

DTIC Science & Technology

2017-03-23

Technique presented at/published to HINMAN Dental Society, 33 Lenox Pointe NE, Atlanta, GA, 23-25 March 2017 in accordance with MDWI 41-108, has...DISAPPROVED D N/A Academic presentation on dental techniques using publicly avai lable in format ion. A ppropriate disclaim ers included. Approved 28

APHiD: Hierarchical Task Placement to Enable a Tapered Fat Tree Topology for Lower Power and Cost in HPC Networks

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

Michelogiannakis, George; Ibrahim, Khaled Z.; Shalf, John

The power and procurement cost of bandwidth in system-wide networks has forced a steady drop in the byte/flop ratio. This trend of computation becoming faster relative to the network is expected to hold. In this paper, we explore how cost-oriented task placement enables reducing the cost of system-wide networks by enabling high performance even on tapered topologies where more bandwidth is provisioned at lower levels. We describe APHiD, an efficient hierarchical placement algorithm that uses new techniques to improve the quality of heuristic solutions and reduces the demand on high-level, expensive bandwidth in hierarchical topologies. We apply APHiD to amore » tapered fat-tree, demonstrating that APHiD maintains application scalability even for severely tapered network configurations. Using simulation, we show that for tapered networks APHiD improves performance by more than 50% over random placement and even 15% in some cases over costlier, state-of-the-art placement algorithms.« less

A modified efficient purse-string stapling technique (mEST) that uses a new metal rod for intracorporeal esophagojejunostomy in laparoscopic total gastrectomy

PubMed Central

Moon, Jeong-Ho; Yamamoto, Kazuyoshi; Yanagimoto, Yoshitomo; Sugimura, Keijirou; Miyata, Hiroshi; Yano, Masahiko; Sakon, Masato

2017-01-01

Intracorporeal esophagojejunostomy after laparoscopic total gastrectomy is technically difficult because this procedure should be performed in a narrow surgical field in the upper abdomen even when completely laparoscopic approaches are used. The placement of the anvil of a circular stapling device into the esophagus and connection the instrument to the anvil are extremely difficult steps in this surgery. Therefore, we developed a simple technique for intracorporeal esophagojejunostomy using hemi-double stapling technique; we named this technique the efficient purse-string stapling technique (EST). More recently, we have developed a modified EST (mEST) that utilizes a new stainless steel anvil rod instead of a plastic rod. Relative to the plastic rod, the steel rod is reusable and shorter; thus, it was easier to perform anvil placement into the esophagus with the steel rod. Anvil preparation for mEST: a stainless steel rod is attached to the shaft of the anvil, and the needle and thread are sutured to the tip of the rod. After complete insertion of the anvil into the esophageal cavity, the needle and thread are used to penetrate the anterior esophageal wall, and the esophagus is then clamped using a linear stapler just distal to the site penetrated by the thread. The linear stapler is fired, and anvil placement in the esophagus is simultaneously accomplished. After the rod is removed from the anvil, the instrument is intracorporeally connected to the anvil and then fired to complete the gastrojejunostomy. This technique is simple and facilitates intracorporeal reconstruction procedures in laparoscopic total gastrectomy. PMID:28815221

Fully customized placement of orthodontic miniplates: a novel clinical technique

PubMed Central

2014-01-01

Introduction The initial stability and survival rate of orthodontic mini-implants are highly dependent on the amount of cortical bone at their insertion site. In areas with limited bone availability, mini-plates are preferred to provide effective skeletal anchorage. The purpose of this paper was to present a new clinical technique for the insertion of mini-plates. Methods In order to apply this new technique, a cone-beam image of the insertion area is required. A software (Galaxy Sirona, Bensheim, Germany) is used to construct a three-dimensional image of the scanned area and to virtually determine the exact location of the mini-plate as well as the position of the fixation screws. A stereolithographic model (STL) is then created by means of a three-dimensional scanner. Prior to its surgical insertion, the bone plate is adapted to the stereo-lithographic model. Finally, a custom transfer jig is fabricated in order to assist with accurate placement of the mini-plate intra-operatively. Results The presented technique minimizes intra-operative decision making, because the final position of the bone plate is determined pre-surgically. This significantly reduces the duration of the surgical procedure and improves its outcome. Conclusions A novel method for surgical placement of orthodontic mini-plates is presented. The technique facilitates accurate adaptation of mini-plates and insertion of retaining surgical screws; thereby enabling clinicians to more confidently increase the use of bone plates, especially in anatomical areas where the success of non-osseointegrated mini-screws is less favorable. PMID:24886597

Comparison of computer-assisted surgery with conventional technique for the treatment of axial distal phalanx fractures in horses: an in vitro study.

PubMed

Andritzky, Juliane; Rossol, Melanie; Lischer, Christoph; Auer, Joerg A

2005-01-01

To compare the precision obtained with computer-assisted screw insertion for treatment of mid-sagittal articular fractures of the distal phalanx (P3) with results achieved with a conventional technique. In vitro experimental study. Thirty-two cadaveric equine limbs. Four groups of 8 limbs were studied. Either 1 or 2 screws were inserted perpendicular to an imaginary axial fracture of P3 using computer-assisted surgery (CAS) or conventional technique. Screw insertion time, predetermined screw length, inserted screw length, fit of the screw, and errors in placement were recorded. CAS technique took 15-20 minutes longer but resulted in greater precision of screw length and placement compared with the conventional technique. Improved precision in screw insertion with CAS makes insertion of 2 screws possible for repair of mid-sagittal P3 fractures. CAS although expensive improves precision in screw insertion into P3 and consequently should yield improved clinical outcome.

NASA Out-of-Autoclave Process Technology Development

NASA Technical Reports Server (NTRS)

Johnston, Norman, J.; Clinton, R. G., Jr.; McMahon, William M.

2000-01-01

Polymer matrix composites (PMCS) will play a significant role in the construction of large reusable launch vehicles (RLVs), mankind's future major access to low earth orbit and the international space station. PMCs are lightweight and offer attractive economies of scale and automated fabrication methodology. Fabrication of large RLV structures will require non-autoclave methods which have yet to be matured including (1) thermoplastic forming: heated head robotic tape placement, sheet extrusion, pultrusion, molding and forming; (2) electron beam curing: bulk and ply-by-ply automated placement; (3) RTM and VARTM. Research sponsored by NASA in industrial and NASA laboratories on automated placement techniques involving the first 2 categories will be presented.

Endoscopic transaqueductal placement of a single-catheter cyst-ventriculoperitoneal shunt in a neonate with Dandy-Walker malformation-associated hydrocephalus: case report.

PubMed

Morigaki, Ryoma; Pooh, Kyong-Hon; Nakagawa, Yoshinobu

2011-01-01

A neonate with hydrocephalus associated with Dandy-Walker malformation was successfully treated with an endoscopic placement of a transaqueductal ventricular single catheter. The modified catheter was provided with additional fenestration on its proximal side to allow simultaneous drainage from both the supra- and infratentorial compartments. This technique is well known for isolated fourth ventricles, but has not been applied to hydrocephalus associated with Dandy-Walker malformation. The cyst-ventriculoperitoneal shunt effectively drained both compartments. The patient was doing well 18 months after the surgical procedure. Endoscopic transaqueductal shunt placement can be considered, especially in patients with aqueductal patency.

Modified Miniplates for Temporary Skeletal Anchorage in Orthodontics: Placement and Removal Surgeries

PubMed Central

Cornelis, Marie A.; Scheffler, Nicole R.; Mahy, Pierre; Siciliano, Sergio; De Clerck, Hugo J.; Tulloch, J.F. Camilla

2009-01-01

Purpose Skeletal anchorage systems are increasingly used in orthodontics. This article describes the techniques of placement and removal of modified surgical miniplates used for temporary orthodontic anchorage and reports surgeons’ perceptions of their use. Patients and Methods We enrolled 97 consecutive orthodontic patients having miniplates placed as an adjunct to treatment. A total of 200 miniplates were placed by 9 oral surgeons. Patients and surgeons completed questionnaires after placement and removal surgeries. Results Fifteen miniplates needed to be removed prematurely. Antibiotics and anti-inflammatories were generally prescribed after placement but not after removal surgery. Most surgeries were performed with the patient under local anesthesia. Placement surgery lasted on average between 15 and 30 minutes per plate and was considered by the surgeons to be very easy to moderately easy. The surgery to remove the miniplates was considered easier and took less time. The patients’ chief complaint was swelling, lasting on average 5.3 ± 2.8 days after placement and 4.5 ± 2.6 days after removal. Conclusions Although miniplate placement/removal surgery requires the elevation of a flap, this was considered an easy and relatively short surgical procedure that can typically be performed with the patient under local anesthesia without complications, and it may be considered a safe and effective adjunct for orthodontic treatment. PMID:18571028

The modeling and design of the Annular Suspension and Pointing System /ASPS/. [for Space Shuttle

NASA Technical Reports Server (NTRS)

Kuo, B. C.; Lin, W. C. W.

1979-01-01

The Annular Suspension and Pointing System (ASPS) is a payload auxiliary pointing device of the Space Shuttle. The ASPS is comprised of two major subassemblies, a vernier and a coarse pointing subsystem. The three functions provided by the ASPS are related to the pointing of the payload, centering the payload in the magnetic actuator assembly, and tracking the payload mounting plate and shuttle motions by the coarse gimbals. The equations of motion of a simplified planar model of the ASPS are derived. Attention is given to a state diagram of the dynamics of the ASPS with position-plus-rate controller, the nonlinear spring characteristic for the wire-cable torque of the ASPS, the design of the analog ASPS through decoupling and pole placement, and the time response of different components of the continuous control system.

IECON '87: Industrial applications of control and simulation; Proceedings of the 1987 International Conference on Industrial Electronics, Control, and Instrumentation, Cambridge, MA, Nov. 3, 4, 1987

NASA Technical Reports Server (NTRS)

Hartley, Tom T. (Editor)

1987-01-01

Recent advances in control-system design and simulation are discussed in reviews and reports. Among the topics considered are fast algorithms for generating near-optimal binary decision programs, trajectory control of robot manipulators with compensation of load effects via a six-axis force sensor, matrix integrators for real-time simulation, a high-level control language for an autonomous land vehicle, and a practical engineering design method for stable model-reference adaptive systems. Also addressed are the identification and control of flexible-limb robots with unknown loads, adaptive control and robust adaptive control for manipulators with feedforward compensation, adaptive pole-placement controllers with predictive action, variable-structure strategies for motion control, and digital signal-processor-based variable-structure controls.

Modeling and stability of segmented reflector telescopes - A decentralized approach

NASA Technical Reports Server (NTRS)

Ryaciotaki-Boussalis, Helen A.; Ih, Che-Hang Charles

1990-01-01

The decentralization of a segmented reflector telescope based on a finite-element model of its structure is considered. The decentralization of the system at the panel level is considered. Each panel is originally treated as an isolated subsystem so that the controller design is performed independently at the local level, and then applied to the composite system for stability analysis. The panel-level control laws were designed by means of pole placement using local output feedback. Simulation results show a better 1000:1 vibration attenuation in panel position when compared to the open-loop system. It is shown that the overall closed-loop system is exponentially stable provided that certain conditions are met. The advantage to the decentralized approach is that the design is performed in terms of the low-dimensionality subsystems, thus drastically reducing the design computational complexities.

Real-time multi-DSP control of three-phase current-source unity power factor PWM rectifier

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

Xiao Wang; Boon-Teck Ooi

1993-07-01

The design of a real-time multi-DSP controller for a high-quality six-valve three-phase current-source unity power factor PWM rectifier is discussed in this paper. With the decoupler preprocessor and the dynamic trilogic PWM trigger scheme, each of the three input currents can be controlled independently. Based on the a-b-c frame system model and the fast parallel computer control, the pole-placement control method is implemented successfully to achieve fast response in the ac currents. The low-frequency resonance in the ac filter L-C networks has been damped effectively. The experimental results are obtained from a 1-kVA bipolar transistor current-source PWM rectifier with amore » real-time controller using three TMS320C25 DSP's.« less

IIR digital filter design for powerline noise cancellation of ECG signal using arduino platform

NASA Astrophysics Data System (ADS)

Rahmatillah, Akif; Ataulkarim

2017-05-01

Powerline noise has been one of significant noises of Electrocardiogram (ECG) signal measurement. This noise is characterized by a sinusoidal signal which has 50 Hz of noise and 0.3 mV of maximum amplitude. This paper describes the design of IIR Notch filter design to reject a 50 Hz power line noise. IIR filter coefficients were calculated using pole placement method with three variations of band stop cut off frequencies of (49-51)Hz, (48 - 52)Hz, and (47 - 53)Hz. The algorithm and coefficients of filter were embedded to Arduino DUE (ARM 32 bit microcontroller). IIR notch filter designed has been able to reject power line noise with average square of error value of 0.225 on (49-51) Hz filter design and 0.2831 on (48 - 52)Hz filter design.

A serious game for learning ultrasound-guided needle placement skills.

PubMed

Chan, Wing-Yin; Qin, Jing; Chui, Yim-Pan; Heng, Pheng-Ann

2012-11-01

Ultrasound-guided needle placement is a key step in a lot of radiological intervention procedures such as biopsy, local anesthesia and fluid drainage. To help training future intervention radiologists, we develop a serious game to teach the skills involved. We introduce novel techniques for realistic simulation and integrate game elements for active and effective learning. This game is designed in the context of needle placement training based on the some essential characteristics of serious games. Training scenarios are interactively generated via a block-based construction scheme. A novel example-based texture synthesis technique is proposed to simulate corresponding ultrasound images. Game levels are defined based on the difficulties of the generated scenarios. Interactive recommendation of desirable insertion paths is provided during the training as an adaptation mechanism. We also develop a fast physics-based approach to reproduce the shadowing effect of needles in ultrasound images. Game elements such as time-attack tasks, hints and performance evaluation tools are also integrated in our system. Extensive experiments are performed to validate its feasibility for training.

Plastic Biliary Stent Migration During Multiple Stents Placement and Successful Endoscopic Removal Using Intra-Stent Balloon Inflation Technique: A Case Report and Literature Review.

PubMed

Calcara, Calcedonio; Broglia, Laura; Comi, Giovanni; Balzarini, Marco

2016-02-05

Late migration of a plastic biliary stent after endoscopic placement is a well known complication, but there is little information regarding migration of a plastic stent during multiple stents placement. A white man was hospitalized for severe jaundice due to neoplastic hilar stenosis. Surgical eligibility appeared unclear on admission and endoscopy was carried out, but the first stent migrated proximally at the time of second stent insertion. After failed attempts with various devices, the migrated stent was removed successfully through cannulation with a dilation balloon. The migration of a plastic biliary stent during multiple stents placement is a possible complication. In this context, extraction can be very complicated. In our patient, cannulation of a stent with a dilation balloon was the only effective method.

Advances in in situ inspection of automated fiber placement systems

NASA Astrophysics Data System (ADS)

Juarez, Peter D.; Cramer, K. Elliott; Seebo, Jeffrey P.

2016-05-01

Automated Fiber Placement (AFP) systems have been developed to help take advantage of the tailorability of composite structures in aerospace applications. AFP systems allow the repeatable placement of uncured, spool fed, preimpregnated carbon fiber tape (tows) onto substrates in desired thicknesses and orientations. This automated process can incur defects, such as overlapping tow lines, which can severely undermine the structural integrity of the part. Current defect detection and abatement methods are very labor intensive, and still mostly rely on human manual inspection. Proposed is a thermographic in situ inspection technique which monitors tow placement with an on board thermal camera using the preheated substrate as a through transmission heat source. An investigation of the concept is conducted, and preliminary laboratory results are presented. Also included will be a brief overview of other emerging technologies that tackle the same issue.

Spin Axis Distribution of the Hungaria Asteroids via Lightcurve Inversion

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2015-05-01

In the past decade or so, the influence on small asteroids of the YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effect, which is the asymmetric thermal emission of received sunlight, has been firmly established. The two strongest pieces of evidence are the nearly flat distribution of rotation rates of small asteroids and the distribution of spin axes (poles). YORP theory says that the spin axes, barring outside influences, are eventually forced to low obliquities, i.e., the poles are located near the north or south ecliptic poles. This would seem natural for objects with low orbital inclinations. However, for objects with high orbital inclinations, such as the Hungarias, there are some questions if this would still be the case. The authors and other observers have accumulated dense lightcurves of the Hungaria asteroids for more than a decade. The combination of these dense lightcurves and sparse data from asteroid search surveys has allowed using lightcurve inversion techniques to determine the spin axes for almost 75 Hungaria asteroids. The results confirm earlier works that show an anisotropic distribution of spin axes that favors the ecliptic poles and, as predicted for the Hungarias, a preponderance of retrograde rotators.

Modal analysis and control of flexible manipulator arms. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Neto, O. M.

1974-01-01

The possibility of modeling and controlling flexible manipulator arms was examined. A modal approach was used for obtaining the mathematical model and control techniques. The arm model was represented mathematically by a state space description defined in terms of joint angles and mode amplitudes obtained from truncation on the distributed systems, and included the motion of a two link two joint arm. Three basic techniques were used for controlling the system: pole allocation with gains obtained from the rigid system with interjoint feedbacks, Simon-Mitter algorithm for pole allocation, and sensitivity analysis with respect to parameter variations. An improvement in arm bandwidth was obtained. Optimization of some geometric parameters was undertaken to maximize bandwidth for various payload sizes and programmed tasks. The controlled system is examined under constant gains and using the nonlinear model for simulations following a time varying state trajectory.

Design of an adaptive super-twisting decoupled terminal sliding mode control scheme for a class of fourth-order systems.

PubMed

Ashtiani Haghighi, Donya; Mobayen, Saleh

2018-04-01

This paper proposes an adaptive super-twisting decoupled terminal sliding mode control technique for a class of fourth-order systems. The adaptive-tuning law eliminates the requirement of the knowledge about the upper bounds of external perturbations. Using the proposed control procedure, the state variables of cart-pole system are converged to decoupled terminal sliding surfaces and their equilibrium points in the finite time. Moreover, via the super-twisting algorithm, the chattering phenomenon is avoided without affecting the control performance. The numerical results demonstrate the high stabilization accuracy and lower performance indices values of the suggested method over the other ones. The simulation results on the cart-pole system as well as experimental validations demonstrate that the proposed control technique exhibits a reasonable performance in comparison with the other methods. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Stent placement with the monorail technique for treatment of mesenteric artery stenosis.

PubMed

Schaefer, Philipp J; Schaefer, Fritz K W; Hinrichsen, Holger; Jahnke, Thomas; Charalambous, Nikolas; Heller, Martin; Mueller-Huelsbeck, Stefan

2006-04-01

To analyze the immediate and midterm success of stenting of mesenteric arteries by a monorail technique in patients with chronic mesenteric ischemia. In this prospective case series, 19 patients (11 male, 8 female; mean age, 62.9 +/- 10.4 y; range, 36-82 y) with 23 symptomatic stenoses of mesenteric arteries were treated with stent placement by a monorail technique in a radiologic intervention center over a period of 4.5 years. Clinical examinations and duplex sonography were used to evaluate the stents' patency and clinical success. Kaplan-Meier graphs were calculated to analyze the patency and freedom-from-symptom rate. Initial technical success rate was 22/23 (96%). Mean follow-up was 17 months (range, 1-58 mo). Primary patency and primary clinical success rates were 82% and 78%, respectively. According to Kaplan-Meier tables, the patency rates were 96%, 87%, 76%, and 61% at 0, 1, 15, and 24 months, respectively, and the freedom-from-symptom rates were 95%, 90%, 72%, and 54% at 0, 1, 24, and 30 months, respectively. No peri-interventional complications occurred. Two patients died of cardiac failure in the hospital within 30 days after intervention; deaths were not related to the intervention. Stent placement by a monorail technique in mesenteric arteries is an effective and safe treatment for symptomatic stenoses in patients with chronic mesenteric ischemia after a mean follow-up of 17 months.

Accuracy analysis of pedicle screw placement in posterior scoliosis surgery: comparison between conventional fluoroscopic and computer-assisted technique.

PubMed

Kotani, Yoshihisa; Abumi, Kuniyoshi; Ito, Manabu; Takahata, Masahiko; Sudo, Hideki; Ohshima, Shigeki; Minami, Akio

2007-06-15

The accuracy of pedicle screw placement was evaluated in posterior scoliosis surgeries with or without the use of computer-assisted surgical techniques. In this retrospective cohort study, the pedicle screw placement accuracy in posterior scoliosis surgery was compared between conventional fluoroscopic and computer-assisted surgical techniques. There has been no study systemically analyzing the perforation pattern and comparative accuracy of pedicle screw placement in posterior scoliosis surgery. The 45 patients who received posterior correction surgeries were divided into 2 groups: Group C, manual control (25 patients); and Group N, navigation surgery (20 patients). The average Cobb angles were 73.7 degrees and 73.1 degrees before surgery in Group C and Group N, respectively. Using CT images, vertebral rotation, pedicle axes as measured to anteroposterior sacral axis and vertebral axis, and insertion angle error were measured. In perforation cases, the angular tendency, insertion point, and length abnormality were evaluated. The perforation was observed in 11% of Group C and 1.8% in Group N. In Group C, medial perforations of left screws were demonstrated in 8 of 9 perforated screws and 55% were distributed either in L1 or T12. The perforation consistently occurred in pedicles in which those axes approached anteroposterior sacral axis within 5 degrees . The average insertion errors were 8.4 degrees and 5.0 degrees in Group C and Group N, respectively, which were significantly different (P < 0.02). The medial perforation in Group C occurred around L1, especially when pedicle axis approached anteroposterior sacral axis. This consistent tendency was considered as the limitation of fluoroscopic screw insertion in which horizontal vertebral image was not visible. The use of surgical navigation system successfully reduced the perforation rate and insertion angle errors, demonstrating the clear advantage in safe and accurate pedicle screw placement of scoliosis surgery.

A pulsatile pressure waveform is a sensitive marker for confirming the location of the thoracic epidural space.

PubMed

Lennox, Pamela H; Umedaly, Hamed S; Grant, Raymer P; White, S Adrian; Fitzmaurice, Brett G; Evans, Kenneth G

2006-10-01

The purpose of this study was to assess the validity of using a pulsatile, pressure waveform transduced from the epidural space through an epidural needle or catheter to confirm correct placement for maximal analgesia and to compare 3 different types of catheters' ability to transduce a waveform. A single-center, prospective, randomized trial. A tertiary-referral hospital. Eighty-one patients undergoing posterolateral thoracotomy who required a thoracic epidural catheter for postoperative pain management. Each epidural needle and each epidural catheter was transduced to determine if there was a pulsatile waveform exhibited. Sensitivity of the pulsatile waveform transduced through an epidural needle to identify correct placement of the epidural needle and the sensitivity of each catheter type to identify placement were compared. In 79 of 81 cases (97.5%), the waveform transduced directly through the epidural needle had a pulsatile characteristic as determined by blinded observers. In a total of 53 of 81 epidural catheters (65.4%), the transduced waveform displayed pulsations. Twenty-four of 27 catheters in group S-P/Sims Portex (Smiths Medical MD, Inc, St Paul, MN) (88.9%) transduced a pulsatile tracing from the epidural space, a significantly greater percentage than in the other 2 groups (p = 0.02). The technique of transducing the pressure waveform from the epidural needle inserted in the epidural space is a sensitive and reliable alternative to other techniques for confirmation of correct epidural catheter placement. The technique is simple, sensitive, and inexpensive and uses equipment available in any operating room.

Implementation of an electromagnetic imaging system to facilitate nasogastric and post-pyloric feeding tube placement in patients with and without critical illness.

PubMed

Windle, E M; Beddow, D; Hall, E; Wright, J; Sundar, N

2010-02-01

Artificial nutrition support is required to optimise nutritional status in many patients. Traditional methods of placing feeding tubes may incur clinical risk and financial costs. A technique facilitating placement of nasogastric and post-pyloric tubes via electromagnetic visual guidance may reduce the need for X-ray exposure, endoscopy time and the use of parenteral nutrition. The present study aimed to audit use of such a system at initial implementation in patients within an acute NHS Trust. A retrospective review was undertaken of dietetic and medical records for the first 14 months of using the Cortrak system. Data were collected on referral origin, preparation of the patient prior to insertion, placement success rates and need for X-ray. Cost analysis was also performed. Referrals were received from primary consultants or consultant intensivists, often on the advice of the dietitian. Fifty-nine percent of patients received prokinetic therapy at the time of placement. Thirty-nine tube placements were attempted. Sixty-nine percent of referrals for post-pyloric tube placement resulted in successful placement. X-ray films were requested for 22% of all attempted post-pyloric placements. Less than half of nasogastric tubes were successfully passed, although none of these required X-ray confirmation. The mean cost per tube insertion attempt was 111 pounds. This system confers advantages, particularly in terms of post-pyloric tube placement, even at this early stage of implementation. A reduction in clinical risk and cost avoidance related to X-ray exposure, the need for endoscopic tube placement and parenteral nutrition have been achieved. The implementation of this system should be considered in other centres.

Asteroid (16) Psyche: Triaxial Ellipsoid Dimensions and Rotational Pole from Keck II NIRC2 AO Images and Keck I OSIRIS Images

NASA Astrophysics Data System (ADS)

Drummond, Jack D.; Conrad, Al; Reddy, Vishnu; de Kleer, Katherine R.; Adamkovics, Mate; de Pater, Imke; Merline, William J.; Tamblyn, Peter

2016-10-01

Adaptive optics (AO) images of asteroid (16) Psyche obtained at 4 epochs with the NIRC2 camera at the 10m W. M. Keck Observatory (Keck II) on UT 2015 December 25 lead to triaxial ellipsoid diameters of 279±4 x 230±2 x 195±14 km, and a rotational pole at RA=29° and Dec=-2°. Adding 6 more epochs obtained nearly simultaneously with the OSIRIS system at Keck I, as well as two more epochs from Keck II in 2009, yields diameters of 273±2 x 232±2 x 165±3 km, and a pole at RA=37° and Dec=+1°. (Errors are formal fit parameter uncertainties; an additional 4% uncertainty is possible from systematic biases.) The differing perspectives between 2015 (sub-Earth latitude Θ=-50°) and 2009 (Θ=-6°) improves primarily the c dimension and the location of the rotational pole, but illustrates how well images from even a single night can determine the size, shape, and pole of an asteroid. The 2015 observations were obtained as part of a campaign to study Psyche with many techniques over a few months, including radar from Arecibo and images from Magellan.These handful of images show the same rugged outline as the radius vector model available on the DAMIT website, constructed from many lightcurves and scaled by previous Keck AO images. In fact Psyche has rotated some 125,350 times between the first lightcurve in 1955 and our 2015 AO images, exactly 60 years apart to the day. Since the asteroid has such a high obliquity, these lightcurves have scanned well into both northern and southern hemispheres. The difference between the pole derived from our images and the radius vector model pole is only 7°, and the mean diameters of Psyche are 219 and 211 km, respectively.

RBT-GA: a novel metaheuristic for solving the multiple sequence alignment problem

PubMed Central

Taheri, Javid; Zomaya, Albert Y

2009-01-01

Background Multiple Sequence Alignment (MSA) has always been an active area of research in Bioinformatics. MSA is mainly focused on discovering biologically meaningful relationships among different sequences or proteins in order to investigate the underlying main characteristics/functions. This information is also used to generate phylogenetic trees. Results This paper presents a novel approach, namely RBT-GA, to solve the MSA problem using a hybrid solution methodology combining the Rubber Band Technique (RBT) and the Genetic Algorithm (GA) metaheuristic. RBT is inspired by the behavior of an elastic Rubber Band (RB) on a plate with several poles, which is analogues to locations in the input sequences that could potentially be biologically related. A GA attempts to mimic the evolutionary processes of life in order to locate optimal solutions in an often very complex landscape. RBT-GA is a population based optimization algorithm designed to find the optimal alignment for a set of input protein sequences. In this novel technique, each alignment answer is modeled as a chromosome consisting of several poles in the RBT framework. These poles resemble locations in the input sequences that are most likely to be correlated and/or biologically related. A GA-based optimization process improves these chromosomes gradually yielding a set of mostly optimal answers for the MSA problem. Conclusion RBT-GA is tested with one of the well-known benchmarks suites (BALiBASE 2.0) in this area. The obtained results show that the superiority of the proposed technique even in the case of formidable sequences. PMID:19594869

Effect of different mixing and placement methods on the quality of MTA apical plug in simulated apexification model.

PubMed

Ghasemi, Negin; Janani, Maryam; Razi, Tahmineh; Atharmoghaddam, Faezeh

2017-03-01

It is necessary apical plug material to exhibit proper adaptation with the root canal walls. Presence of voids at the interface between the root canal wall and this material result in micro leakage, which might have a relationship with post treatment disease. The aim of the present study was to evaluate the effect of different mixing (manual and ultrasonic) and placement (manual and manual in association with indirect ultrasonic) method of Mineral Trioxide Aggregate (MTA) on the void count and dimension in the apical plug in natural teeth with simulated open apices. Eighty human maxillary central incisors were selected. After simulation of the open apex model, the teeth were assigned to 4 groups based on the mixing and placement techniques of MTA: group 1, manual mixing and manual placement; group 2, manual mixing and manual placement in association with indirect ultrasonic; group 3, ultrasonic mixing and and manual placement; and group 4, ultrasonic mixing and manual placement in association with indirect ultrasonic. The prepared samples were placed within gypsum sockets in which the periodontal ligament was reconstructed with polyether impression material. In group 1, after mixing, the material was condensed with a hand plugger. In group 2, after mixing, the ultrasonic tip was contacted with the hand plugger for 2 seconds. In groups 3 and 4, mixing was carried out with the ultrasonic tip for 5 seconds and in groups 3 and 4, similar to groups 1 and 2, respectively, the materials were placed as apical plugs, measuring 3 mm in length. A wet cotton pellet was placed at canal orifices and dressed with Cavit. After one week, the cone beam computed tomography (CBCT) technique was used to count the number of voids between the material and root canal walls. The void dimensions were determined using the following scoring system: score 1, absence of voids; score 2, the void size less than half of the dimensions of the evaluated cross-section; score 3, the void size larger than half of the dimensions of the evaluated cross-section. Chi-squared and Fisher's exact tests were used for statistical analyses. Statistical significance was set at P <0.05. The maximum (13) and minimum (3) number of voids were detected in groups 2 and 3, respectively. There were no significant differences between groups 1 and 3 in the number of voids ( p >0.05). Evaluation of void dimensions showed no score 3 in any of the study groups and the dimensions of all the voids conformed to score 2. Under the limitations of the present study, use of ultrasonic mixing and manual placement techniques resulted in a decrease in the number of voids in the apical plug. Key words: Apical plug, MTA, ultrasonic, void.

Electromagnetic navigation reduces surgical time and radiation exposure for proximal interlocking in retrograde femoral nailing.

PubMed

Somerson, Jeremy S; Rowley, David; Kennedy, Chad; Buttacavoli, Frank; Agarwal, Animesh

2014-07-01

To compare the time required for proximal locking screw placement between a standard freehand technique and the navigated technique, and to quantify the reduction in ionizing radiation exposure. A fresh frozen cadaver model was used for 48 proximal interlocking screw procedures. Each procedure consisted of insertion of 2 anteroposterior locking screws. Standard fluoroscopic technique was used for 24 procedures, and an electromagnetic navigation system was used for the remaining 24 procedures. Procedure duration was recorded using an electronic timer and radiation doses were documented. Mean total insertion time for both proximal interlocking screws was 405 ± 165.7 seconds with the freehand technique and 311 ± 78.3 seconds in the navigation group (P = 0.002). All procedures resulted in successful locking screw placement. Mean ionizing radiation exposure time for proximal locking was 29.5 ± 12.8 seconds. Proximal locking screw insertion using the navigation technique evaluated in this work was significantly faster than the standard fluoroscopic method. The navigated technique is effective and has the potential to prevent ionizing radiation exposure.

Solution of magnetic field and eddy current problem induced by rotating magnetic poles (abstract)

NASA Astrophysics Data System (ADS)

Liu, Z. J.; Low, T. S.

1996-04-01

The magnetic field and eddy current problems induced by rotating permanent magnet poles occur in electromagnetic dampers, magnetic couplings, and many other devices. Whereas numerical techniques, for example, finite element methods can be exploited to study various features of these problems, such as heat generation and drag torque development, etc., the analytical solution is always of interest to the designers since it helps them to gain the insight into the interdependence of the parameters involved and provides an efficient tool for designing. Some of the previous work showed that the solution of the eddy current problem due to the linearly moving magnet poles can give satisfactory approximation for the eddy current problem due to rotating fields. However, in many practical cases, especially when the number of magnet poles is small, there is significant effect of flux focusing due to the geometry. The above approximation can therefore lead to marked errors in the theoretical predictions of the device performance. Bernot et al. recently described an analytical solution in a polar coordinate system where the radial field is excited by a time-varying source. A discussion of an analytical solution of the magnetic field and eddy current problems induced by moving magnet poles in radial field machines will be given in this article. The theoretical predictions obtained from this method is compared with the results obtained from finite element calculations. The validity of the method is also checked by the comparison of the theoretical predictions and the measurements from a test machine. It is shown that the introduced solution leads to a significant improvement in the air gap field prediction as compared with the results obtained from the analytical solution that models the eddy current problems induced by linearly moving magnet poles.

Anaerobic threshold assessment through the ventilatory method during roller-ski skating testing: right or wrong?

PubMed

Fabre, Nicolas; Bortolan, Lorenzo; Pellegrini, Barbara; Zerbini, Livio; Mourot, Laurent; Schena, Federico

2012-02-01

This study aimed at questioning the validity of the ventilatory method to determine the anaerobic threshold (respiratory compensation point [RCP]) during an incremental roller-ski skating test to exhaustion. Nine elite crosscountry skiers were evaluated. The skiers carried out an incremental roller-ski test on a treadmill with the V2 skating technique. Ventilatory parameters were continuously collected breath by breath, thanks to a portable gas exchange measurement system. Poling signal was obtained using instrumented ski poles. For each stage, ventilatory and poling signals were synchronized and averaged. The poor coefficient of interobserver reliability for the time at RCP confirmed the great difficulty felt by the 3 blinded reviewers for the RCP determination. Moreover, the reviewer agreed with the impossibility of determining RCP in 4 of the 9 skiers. There was no significant difference between breathing frequency (Bf) and poling frequency (Pf) during the last 8 stages. However, it seems that the differences observed during the first stages arose from the use of either a strictly 1:1 or a 1:2 Bf to Pf ratio when the exercise intensity was still moderate. So, even if there were significant differences between the frequencies, the Bf was strictly subordinate to the Pf during the entire test. In the same way, the normalized tidal volume and peak poling forces curves were superposable. These findings showed that when the upper body is mainly involved in the propulsion, the determinants of the ventilation are strictly dependent on the poling pattern during an incremental test to exhaustion. Thus, during roller-ski skating, the determination of RCP must be used cautiously because too much depending on mechanical factors.

Cell division in two large pennate diatoms Hantzschia and Nitzschia III. A new proposal for kinetochore function during prometaphase

PubMed Central

1980-01-01

Prometaphase in two large species of diatoms is examined, using the following techniques: (a) time-lapse cinematography of chromosome movements in vivo; (b) electron microscopy of corresponding stages: (c) reconstruction of the microtubules (MTs) in the kinetochore fiber of chromosomes attached to the spindle. In vivo, the chromosomes independently commence oscillations back and forth to one pole. The kinetochore is usually at the leading edge of such chromosome movements; a variable time later both kinetochores undergo such oscillations but toward opposite poles and soon stretch poleward to establish stable bipolar attachment. Electron microscopy of early prometaphase shows that the kinetochores usually laterally associate with MTs that have one end attached to the spindle pole. At late prometaphase, most chromosomes are fully attached to the spindle, but the kinetochores on unattached chromosomes are bare of MTs. Reconstruction of the kinetochore fiber demonstrates that most of its MTs (96%) extend past the kinetochore and are thus apparently not nucleated there. At least one MT terminates at each kinetochore analyzed. Our interpretation is that the conventional view of kinetochore function cannot apply to diatoms. The kinetochore fiber in diatoms appears to be primarily composed of MTs from the poles, in contrast to the conventional view that many MTs of the kinetochore fiber are nucleated by the kinetochore. Similarly, chromosomes appear to initially orient their kinetochores to opposite poles by moving along MTs attached to the poles, instead of orientation effected by kinetochore MTs laterally associating with other MTs in the spindle. The function of the kinetochore in diatoms and other cell types is discussed. PMID:7400213

Simultaneous Versus Sequential Side-by-Side Bilateral Metal Stent Placement for Malignant Hilar Biliary Obstructions.

PubMed

Inoue, Tadahisa; Ishii, Norimitsu; Kobayashi, Yuji; Kitano, Rena; Sakamoto, Kazumasa; Ohashi, Tomohiko; Nakade, Yukiomi; Sumida, Yoshio; Ito, Kiyoaki; Nakao, Haruhisa; Yoneda, Masashi

2017-09-01

Endoscopic bilateral self-expandable metallic stent (SEMS) placement for malignant hilar biliary obstructions (MHBOs) is technically demanding, and a second SEMS insertion is particularly challenging. A simultaneous side-by-side (SBS) placement technique using a thinner delivery system may mitigate these issues. We aimed to examine the feasibility and efficacy of simultaneous SBS SEMS placement for treating MHBOs using a novel SEMS that has a 5.7-Fr ultra-thin delivery system. Thirty-four patients with MHBOs underwent SBS SEMS placement between 2010 and 2016. We divided the patient cohort into those who underwent sequential (conventional) SBS placement between 2010 and 2014 (sequential group) and those who underwent simultaneous SBS placement between 2015 and 2016 (simultaneous group), and compared the groups with respect to the clinical outcomes. The technical success rates were 71% (12/17) and 100% (17/17) in the sequential and simultaneous groups, respectively, a difference that was significant (P = .045). The median procedure time was significantly shorter in the simultaneous group (22 min) than in the sequential group (52 min) (P = .017). There were no significant group differences in the time to recurrent biliary obstruction (sequential group: 113 days; simultaneous group: 140 days) or other adverse event rates (sequential group: 12%; simultaneous group: 12%). Simultaneous SBS placement using the novel 5.7-Fr SEMS delivery system may be more straightforward and have a higher success rate compared to that with sequential SBS placement. This new method may be useful for bilateral stenting to treat MHBOs.

Long-axis view for ultrasound-guided central venous catheter placement via the internal jugular vein.

PubMed

Mahan, Angel F; McEvoy, Matthew D; Gravenstein, Nikolaus

2016-04-01

In modern practice, real-time ultrasound guidance is commonly employed for the placement of internal jugular vein catheters. With a new tool, such as ultrasound, comes the opportunity to refine and further optimize the ultrasound view during jugular vein catheterization. We describe jugular vein access techniques and use the long-axis view as an alternative to the commonly employed short-axis cross-section view for internal jugular vein access and cannulation. The long-axis ultrasound-guided internal jugular vein approach for internal jugular vein cannulation is a useful alternative technique that can provide better needle tip and guidewire visualization than the more traditional short-axis ultrasound view.

Emergency Department Catheter-Associated Urinary Tract Infection Prevention: Multisite Qualitative Study of Perceived Risks and Implemented Strategies.

PubMed

Carter, Eileen J; Pallin, Daniel J; Mandel, Leslie; Sinnette, Corine; Schuur, Jeremiah D

2016-02-01

Existing knowledge of emergency department (ED) catheter-associated urinary tract infection (CAUTI) prevention is limited. We aimed to describe the motivations, perceived risks for CAUTI acquisition, and strategies used to address CAUTI risk among EDs that had existing CAUTI prevention programs. In this qualitative comparative case study, we enrolled early-adopting EDs, that is, those using criteria for urinary catheter placement and tracking the frequency of catheters placed in the ED. At 6 diverse facilities, we conducted 52 semistructured interviews and 9 focus groups with hospital and ED participants. All ED CAUTI programs originated from a hospitalwide focus on CAUTI prevention. Staff were motivated to address CAUTI because they believed program compliance improved patient care. ED CAUTI prevention was perceived to differ from CAUTI prevention in the inpatient setting. To identify areas of ED CAUTI prevention focus, programs examined ED workflow and identified 4 CAUTI risks: (1) inappropriate reasons for urinary catheter placement; (2) physicians' limited involvement in placement decisions; (3) patterns of urinary catheter overuse; and (4) poor insertion technique. Programs redesigned workflow to address risks by (1) requiring staff to specify the medical reason for catheter at the point of order entry and placement; (2) making physicians responsible for determining catheter use; (3) using catheter alternatives to address patterns of overuse; and (4) modifying urinary catheter insertion practices to ensure proper placement. Early-adopting EDs redesigned workflow to minimize catheter use and ensure proper insertion technique. Assessment of ED workflow is necessary to identify and modify local practices that may increase CAUTI risk.

Metal explosion chambers: designing, manufacturing, application

NASA Astrophysics Data System (ADS)

Stoyanovskii, O. I.; Zlobin, B. S.; Shtertser, A. A.; Meshcheryakov, Y. P.

2017-10-01

Designing of explosion chambers is based on research investigations of the chamber body stress-strain state, which is determined by numerical computation and experimentally by the strain gage technique. Studies show that chamber bottoms are the most loaded elements, and maximal stresses arise in chamber poles. Increasing the shell thickness around poles by welding-in an insert is a simple and saving way to solve this problem. There are structural solutions, enabling reliable hermetic closure and preventing leakage of detonation products from the chamber. Explosion chambers are employed in scientific research and in different industrial applications: explosive welding and hardening, synthesis of new materials, disposal of expired ammunition, and etc.

Do JJ Stents Increase the Effectiveness of Extracorporeal Shock Wave Lithotripsy for Pediatric Renal Stones?

PubMed

Gündüz, Metin; Sekmenli, Tamer; Ciftci, İlhan; Elmacı, Ahmet Midhat

2017-01-01

We aimed to evaluate the effects of preoperative urinary catheterization in nephrolithiasis treatment with extracorporeal shock wave lithotripsy (SWL). Patients admitted to the Department of Pediatric Surgery for renal stones between June 2012 and June 2014 were evaluated retrospectively. Patients were divided into 2 groups based on JJ stent placements. Group 1 did not receive JJ stents, while group 2 did. The recorded demographic data for each group included age, gender, stone size, location, sessions, and complications. The Elmed Complit ESWL system was used with 11-13 kV, and 1,000-1,200 shots in patients 2-4 years of age, and 11-14 kV, and 1,000-1,500 shots for patients over 4 years. In group 1, 18 sessions of SWL were performed on 8 female and 2 male children with a mean age of 4.5 (range 2-12) years and stone diameter of 9 (range 7-15) mm. The locations of the renal stones were in the upper pole in 1 patient, 7 in the lower pole, and 2 in the pelvis renalis. Postoperatively, 1 patient had hematuria, 2 had dysuria, and one had a stone in the external urethral meatus. Eighty percent of patients were stone free; there were no fragmentations in 2 patients, and 1 patient discontinued treatment. In group 2, 15 SWL sessions were performed on 5 female and 5 male children aged 4 (range 3-5) and the stone diameter was 9 (range 7-16) mm. The locations of the renal stones were in the upper pole in 6 patients, in the lower pole in 3 patients, and in the ureteropelvic junction in one patient. JJ stents were placed in all patients preoperatively. Postoperatively, 3 patients had hematuria and one had dysuria. At the end of the study, all of the patients were stone free. Statistically, there were no differences in age, gender, stone size, location, and the number of sessions. Our results indicate that SWL without preoperative ureteral stenting is an effective and safe procedure that can be carried out in the pediatric population. Preoperative JJ stenting is unnecessary in patients, especially in those with smaller stone diameters. © 2016 S. Karger AG, Basel.

Elastic Domain Wall Waves in Ferroelectric Ceramics and Single Crystals

DTIC Science & Technology

1988-07-01

properties of piezoelectric and electrostrictive types of ferroelectric ceramics and single crystals. This was for the purpose of shedding light on the...effectiveness and general characteristics of fabrication techniques, as well as exploring basic physical mechanisms playing a role in the technology of...routing and processing devices on small ferroelectric wafers, fabricated by simple inexpensive poling and biasing techniques. Such devices ma) be

The 'WiFi' otoplasty : Combined concentric posterior microchondrectomies and sutures for correction of prominent ears.

PubMed

Hendrickx, Benoit I M M; Hamdi, Moustapha; Zeltzer, Assaf; Greensmith, Andrew

2018-06-01

Prominent ears are by far the most common congenital ear deformity. Many techniques have been described using one or a combination of 3 basic methods: cartilage cutting, cartilage weakening and pure cartilage shaping techniques. The ideal otoplasty technique should yield a natural correction of the deformity, with low recurrence rates and with little risk of complications. A new cartilage shaping technique using closing wedge concentric microchondrectomies through an entirely posterior approach is presented. Between 2006 and 2017, 200 bilateral otoplasties using this 'WiFi' pattern technique were performed. This technique combined with Mustarde sutures is based on the excision of concentric partial thickness cartilage wedges designed in the pattern of the WiFi symbol. There were no major complications such as anterior skin necrosis and no returns to theatre for infections or haematomas. 3 patients (1.5%) had complete recurrence of the deformity and 10 patients (5%) had to undergo a minor revision for recurrence at the upper pole. 5 patients have had exposure of the end of the permanent upper pole scapho-temporal suture more than 3 months after surgery requiring simple outpatient suture trimming/removal without any recurrence of results. Palpable or bridging sutures were present upon clinical examination in 10 patients (5%) but did not require revision surgery. Here, we describe a fast, safe and reliable technique for otoplasty with no need for extensive dissection, which is applicable to the full range of deformity. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Treatment of inferior pole breast cancer with the oncoplastic 'Crescent' technique: the Westmead experience.

PubMed

Ng, E-Ern Ian; French, James; Hsu, Jeremy; Elder, Elisabeth E

2016-01-01

Conservative treatment of inferior breast cancers has been a challenge for breast surgeons due to the high incidence of poor cosmetic outcomes. In 2008, Renouvel et al. described an oncoplastic 'Crescent' technique utilizing an advancement flap to fill the defect after cancer excision in the lower pole of the breast. A follow-up study demonstrated no local recurrence at 45 months and excellent or good cosmetic outcomes in over 70% of patients. This study aims to assess the outcomes of applying this 'Crescent' technique in a breast surgical unit. Retrospective study carried out at Westmead Breast Cancer Institute on 16 patients treated with the 'Crescent' technique. Data regarding patient and tumour characteristics, operative outcomes and complications were obtained. Patients were invited to complete a modified Breast-Q questionnaire and have their photographs taken to assess patient satisfaction and cosmetic outcome. Over 12 months, 16 women underwent the 'Crescent' technique. Mean tumour size was 11.4 mm (range 2.0-36 mm) and median resected volume was 33.0 g (range 15-117 g). One patient (7.1%) had involved margins. One patient returned to theatre for evacuation of a haematoma. Cosmetic outcome was excellent or good in over 80% of patients. The oncoplastic 'Crescent' technique is a safe and reliable technique with good cosmetic outcome that can be implemented in a breast surgical unit. © 2015 Royal Australasian College of Surgeons.

Percutaneous insertion of a proximal humeral locking plate: an anatomic study.

PubMed

Smith, Jason; Berry, Greg; Laflamme, Yves; Blain-Pare, Etienne; Reindl, Rudy; Harvey, Edward

2007-02-01

This cadaveric study sought to evaluate the feasibility of applying a locking proximal humerus plate with a novel minimally invasive technique. A unique pre-contoured locking plate was placed on cadaveric proximal humeri through a described minimally invasive approach. Proximity of the plate and screws to the axillary nerve and their respective surgical tracks were quantified. Safe screw hole placement with respect to the axillary nerve was determined. Risk of entrapment of the nerve beneath the plate was evaluated. Three of the holes near the middle of the locking plate consistently intersected the course of the axillary nerve and were unsafe for percutaneous placement of the screws. The axillary nerve could be palpated during the course of surgery and easily protected from injury. No entrapment of the axillary nerve occurred using this minimally invasive technique. The screw-in locking guide cannot be used with this technique as it caused tenting of the axillary nerve. Placement of a locking proximal humerus plate via a minimally invasive lateral trans-deltoid approach is safe if the locking screws are limited to superior and inferior holes. This can be done safely without entrapment of the axillary beneath the plate. Plate fixation of proximal humerus fractures may now be more desirable with the use of this approach.

Verification of intravenous catheter placement by auscultation--a simple, noninvasive technique.

PubMed

Lehavi, Amit; Rudich, Utay; Schechtman, Moshe; Katz, Yeshayahu Shai

2014-01-01

Verification of proper placement of an intravenous catheter may not always be simple. We evaluated the auscultation technique for this purpose. Twenty healthy volunteers were randomized for 18G catheter inserted intravenously either in the right (12) or left arm (8), and subcutaneously in the opposite arm. A standard stethoscope was placed over an area approximately 3 cm proximal to the tip of the catheter in the presumed direction of the vein to grade on a 0-6 scale the murmur heard by rapidly injecting 2 mL of NaCl 0.9% solution. The auscultation was evaluated by a blinded staff anesthesiologist. All 20 intravenous injection were evaluated as flow murmurs, and were graded an average 5.65 (±0.98), whereas all 20 subcutaneous injections were evaluated as either crackles or no sound, and were graded an average 2.00 (±1.38), without negative results. Sensitivity was calculated as 95%. Specificity and Kappa could not be calculated due to an empty false-positive group. Being simple, handy and noninvasive, we recommend to use the auscultation technique for verification of the proper placement of an intravenous catheter when uncertain of its position. Data obtained in our limited sample of healthy subjects need to be confirmed in the clinical setting.

Design and Validation of an Augmented Reality System for Laparoscopic Surgery in a Real Environment

PubMed Central

López-Mir, F.; Naranjo, V.; Fuertes, J. J.; Alcañiz, M.; Bueno, J.; Pareja, E.

2013-01-01

Purpose. This work presents the protocol carried out in the development and validation of an augmented reality system which was installed in an operating theatre to help surgeons with trocar placement during laparoscopic surgery. The purpose of this validation is to demonstrate the improvements that this system can provide to the field of medicine, particularly surgery. Method. Two experiments that were noninvasive for both the patient and the surgeon were designed. In one of these experiments the augmented reality system was used, the other one was the control experiment, and the system was not used. The type of operation selected for all cases was a cholecystectomy due to the low degree of complexity and complications before, during, and after the surgery. The technique used in the placement of trocars was the French technique, but the results can be extrapolated to any other technique and operation. Results and Conclusion. Four clinicians and ninety-six measurements obtained of twenty-four patients (randomly assigned in each experiment) were involved in these experiments. The final results show an improvement in accuracy and variability of 33% and 63%, respectively, in comparison to traditional methods, demonstrating that the use of an augmented reality system offers advantages for trocar placement in laparoscopic surgery. PMID:24236293

Imaging technique for the complete edentulous patient treated conventionally or with mini implant overdenture

PubMed Central

Meleşcanu Imre, M; Preoteasa, E; Țâncu, AM; Preoteasa, CT

2013-01-01

Rationale. The imaging methods are more and more used in the clinical process of modern dentistry. Once the implant based treatment alternatives are nowadays seen as being the standard of care in edentulous patients, these techniques must be integrated in the complete denture treatment. Aim. The study presents some evaluation techniques for the edentulous patient treated by conventional dentures or mini dental implants (mini SKY Bredent) overdentures, using the profile teleradiography. These offer data useful for an optimal positioning of the artificial teeth and the mini dental implants, favoring to obtain an esthetic and functional treatment outcome. We proposed also a method to conceive a simple surgical guide that allows the prosthetically driven implants placement. Material and method. Clinical case reports were made, highlighting the importance of cephalometric evaluation on lateral teleradiographs in complete edentulous patients. A clinical case that gradually reports the surgical guide preparation (Bredent silicon radio opaque), in order to place the mini dental implants in the best prosthetic and anatomic conditions, was presented. Conclusions. The profile teleradiograph is a useful tool for the practitioner. It allows establishing the optimal site for implant placement, in a good relation with the overdenture. The conventional denture can be easily and relatively costless transformed in a surgical guide used during implant placement. PMID:23599828

Infrared Signal Detection by Upconversion Technique

NASA Technical Reports Server (NTRS)

Wong, Teh-Hwa; Yu, Jirong; Bai, Yingxin; Johnson, William E.

2014-01-01

We demonstrated up-conversion assisted detection of a 2.05-micron signal by using a bulk periodically poled Lithium niobate crystal. The 94% intrinsic up-conversion efficiency and 22.58% overall detection efficiency at pW level of 2.05-micron was achieved.

How do we facilitate international clinical placements for nursing students: A cross-sectional exploration of the structure, aims and objectives of placements.

PubMed

Browne, Caroline A; Fetherston, Catherine M

2018-07-01

International clinical placements provide undergraduate students with a unique and complex clinical learning environment, to explore cultural awareness, experience different health care settings and achieve clinical competencies. Higher education institutions need to consider how to structure these placements to ensure appropriate and achievable aims and learning outcomes. In this study we described the structure, aims and learning outcomes associated with international clinical placement opportunities currently undertaken by Australian undergraduate nursing students in the Asia region. Forty eight percent (n = 18) of the institutions invited responded. Eight institutions met the inclusion criteria, one of which offered three placements in the region, resulting in 10 international placements for which data were provided. An online survey tool was used to collect data during August and September 2015 on international clinical placements conducted by the participating universities. Descriptive data on type and numbers of placements is presented, along with results from the content analysis conducted to explore data from open ended questions on learning aims and outcomes. One hundred students undertook 10 International Clinical Placements offered in the Asian region by eight universities. Variations across placements were found in the length of placement, the number of students participating, facilitator to student ratios and assessment techniques used. Five categories related to the aims of the programs were identified: 'becoming culturally aware through immersion', 'working with the community to promote health', 'understanding the role of nursing within the health care setting', 'translating theory into professional clinical practice', and 'developing relationships in international learning environments'. Four categories related to learning outcomes were identified: 'understanding healthcare and determinants of health', 'managing challenges', 'understanding the role of culture within healthcare' and 'demonstrating professional knowledge, skills and behaviour'. International clinical placements in the Asia region appear to vary greatly from one education institution to the next with no clear consensus from either this study's findings or the literature on which structure, support and assessments lead to greater student learning. Copyright © 2018 Elsevier Ltd. All rights reserved.

Videolaparoscopic Catheter Placement Reduces Contraindications to Peritoneal Dialysis

PubMed Central

Santarelli, Stefano; Zeiler, Matthias; Monteburini, Tania; Agostinelli, Rosa Maria; Marinelli, Rita; Degano, Giorgio; Ceraudo, Emilio

2013-01-01

♦ Background: Videolaparoscopy is considered the reference method for peritoneal catheter placement in patients with previous abdominal surgery. The placement procedure is usually performed with at least two access sites: one for the catheter and the second for the laparoscope. Here, we describe a new one-port laparoscopic procedure that uses only one abdominal access site in patients not eligible for laparotomic catheter placement. ♦ Method: We carried out one-port laparoscopic placement in 21 patients presenting contraindications to blind surgical procedures because of prior abdominal surgery. This technique consists in the creation of a single mini-laparotomy access through which laparoscopic procedures and placement are performed. The catheter, rectified by an introducer, is inserted inside the port. Subsequently, the port is removed, leaving the catheter in pelvic position. The port is reintroduced laterally to the catheter, confirming or correcting its position. Laparotomic placement was performed in a contemporary group of 32 patients without contraindications to blind placement. Complications and long-term catheter outcome in the two groups were evaluated. ♦ Results: Additional interventions during placement were necessary in 12 patients of the laparoscopy group compared with 5 patients of the laparotomy group (p = 0.002). Laparoscopy documented adhesions in 13 patients, with need for adhesiolysis in 6 patients. Each group had 1 intraoperative complication: leakage in the laparoscopy group, and intestinal perforation in the laparotomy group. During the 2-year follow-up period, laparoscopic revisions had to be performed in 6 patients of the laparoscopy group and in 5 patients of the laparotomy group (p = 0.26). The 1-year catheter survival was similar in both groups. Laparoscopy increased by 40% the number of patients eligible to receive peritoneal dialysis. ♦ Conclusions: Videolaparoscopy placement in patients not eligible for blind surgical procedures seems to be equivalent to laparotomic placement with regard to complications and long-term catheter outcome. The number of patients able to receive peritoneal dialysis is substantially increased. PMID:23209040

Effectiveness of electrocardiographic guidance in CVAD tip placement.

PubMed

Walker, Graham; Chan, Raymond J; Alexandrou, Evan; Webster, Joan; Rickard, Claire

International standard practice for the correct confirmation of the central venous access device is the chest X-ray. The intracavitary electrocardiogram-based insertion method is radiation-free, and allows real-time placement verification, providing immediate treatment and reduced requirement for post-procedural repositioning. Relevant databases were searched for prospective randomised controlled trials (RCTs) or quasi RCTs that compared the effectiveness of electrocardiogram-guided catheter tip positioning with placement using surface-anatomy-guided insertion plus chest X-ray confirmation. The primary outcome was accurate catheter tip placement. Secondary outcomes included complications, patient satisfaction and costs. Five studies involving 729 participants were included. Electrocardiogram-guided insertion was more accurate than surface anatomy guided insertion (odds ratio: 8.3; 95% confidence interval (CI) 1.38; 50.07; p=0.02). There was a lack of reporting on complications, patient satisfaction and costs. The evidence suggests that intracavitary electrocardiogram-based positioning is superior to surface-anatomy-guided positioning of central venous access devices, leading to significantly more successful placements. This technique could potentially remove the requirement for post-procedural chest X-ray, especially during peripherally inserted central catheter (PICC) line insertion.

Surgical Navigation Technology Based on Augmented Reality and Integrated 3D Intraoperative Imaging

PubMed Central

Elmi-Terander, Adrian; Skulason, Halldor; Söderman, Michael; Racadio, John; Homan, Robert; Babic, Drazenko; van der Vaart, Nijs; Nachabe, Rami

2016-01-01

Study Design. A cadaveric laboratory study. Objective. The aim of this study was to assess the feasibility and accuracy of thoracic pedicle screw placement using augmented reality surgical navigation (ARSN). Summary of Background Data. Recent advances in spinal navigation have shown improved accuracy in lumbosacral pedicle screw placement but limited benefits in the thoracic spine. 3D intraoperative imaging and instrument navigation may allow improved accuracy in pedicle screw placement, without the use of x-ray fluoroscopy, and thus opens the route to image-guided minimally invasive therapy in the thoracic spine. Methods. ARSN encompasses a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D capabilities, integrated optical cameras for augmented reality navigation, and noninvasive patient motion tracking. Two neurosurgeons placed 94 pedicle screws in the thoracic spine of four cadavers using ARSN on one side of the spine (47 screws) and free-hand technique on the contralateral side. X-ray fluoroscopy was not used for either technique. Four independent reviewers assessed the postoperative scans, using the Gertzbein grading. Morphometric measurements of the pedicles axial and sagittal widths and angles, as well as the vertebrae axial and sagittal rotations were performed to identify risk factors for breaches. Results. ARSN was feasible and superior to free-hand technique with respect to overall accuracy (85% vs. 64%, P < 0.05), specifically significant increases of perfectly placed screws (51% vs. 30%, P < 0.05) and reductions in breaches beyond 4 mm (2% vs. 25%, P < 0.05). All morphometric dimensions, except for vertebral body axial rotation, were risk factors for larger breaches when performed with the free-hand method. Conclusion. ARSN without fluoroscopy was feasible and demonstrated higher accuracy than free-hand technique for thoracic pedicle screw placement. Level of Evidence: N/A PMID:27513166

On the stabilizability of multivariable systems by minimum order compensation

NASA Technical Reports Server (NTRS)

Byrnes, C. I.; Anderson, B. D. O.

1983-01-01

In this paper, a derivation is provided of the necessary condition, mp equal to or greater than n, for stabilizability by constant gain feedback of the generic degree n, p x m system. This follows from another of the main results, which asserts that generic stabilizability is equivalent to generic solvability of a deadbeat control problem, provided mp equal to or less than n. Taken together, these conclusions make it possible to make some sharp statements concerning minimum order stabilization. The techniques are primarily drawn from decision algebra and classical algebraic geometry and have additional consequences for problems of stabilizability and pole-assignability. Among these are the decidability (by a Sturm test) of the equivalence of generic pole-assignability and generic stabilizability, the semi-algebraic nature of the minimum order, q, of a stabilizing compensator, and the nonexistence of formulae involving rational operations and extraction of square roots for pole-assigning gains when they exist, answering in the negative a question raised by Anderson, Bose, and Jury (1975).

Elemental Mercury Diffusion Processes and Concentration at the Lunar Poles

NASA Technical Reports Server (NTRS)

Moxley, Frederick; Killen, Rosemary M.; Hurley, Dana M.

2011-01-01

In 2009, the Lyman Alpha Mapping Project (LAMP) spectrograph onboard the Lunar Reconnaissance Orbiter (LRO) spacecraft made the first detection of element mercury (Hg) vapor in the lunar exosphere after the Lunar Crater Observing and Sensing Satellite (LCROSS) Centaur rocket impacted into the Cabeus crater in the southern polar region of the Moon. The lunar regolith core samples from the Apollo missions determined that Hg had a devolatilized pattern with a concentration gradient increasing with depth, in addition to a layered pattern suggesting multiple episodes of burial and volatile loss. Hg migration on the lunar surface resulted in cold trapping at the poles. We have modeled the rate at which indigenous Hg is lost from the regolith through diffusion out of lunar grains. We secondly modeled the migration of Hg vapor in the exosphere and estimated the rate of cold-trapping at the poles using a Monte Carlo technique. The Hg vapor may be lost from the exosphere via ionization, Jeans escape, or re-impact into the surface causing reabsorption.

Optimal Frequency-Domain System Realization with Weighting

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan; Maghami, Peiman G.

1999-01-01

Several approaches are presented to identify an experimental system model directly from frequency response data. The formulation uses a matrix-fraction description as the model structure. Frequency weighting such as exponential weighting is introduced to solve a weighted least-squares problem to obtain the coefficient matrices for the matrix-fraction description. A multi-variable state-space model can then be formed using the coefficient matrices of the matrix-fraction description. Three different approaches are introduced to fine-tune the model using nonlinear programming methods to minimize the desired cost function. The first method uses an eigenvalue assignment technique to reassign a subset of system poles to improve the identified model. The second method deals with the model in the real Schur or modal form, reassigns a subset of system poles, and adjusts the columns (rows) of the input (output) influence matrix using a nonlinear optimizer. The third method also optimizes a subset of poles, but the input and output influence matrices are refined at every optimization step through least-squares procedures.

Study on dielectric and piezoelectric properties of 0.7 Pb(Mg1/3Nb2/3)O3-0.3 PbTiO3 single crystal with nano-patterned composite electrode

PubMed Central

Chang, Wei-Yi; Huang, Wenbin; Bagal, Abhijeet; Chang, Chih-Hao; Tian, Jian; Han, Pengdi; Jiang, Xiaoning

2013-01-01

Effect of nano-patterned composite electrode and backswitching poling technique on dielectric and piezoelectric properties of 0.7 Pb(Mg1/3Nb2/3)O3-0.3 PbTiO3 was studied in this paper. Composite electrode consists of Mn nano-patterns with pitch size of 200 nm, and a blanket layer of Ti/Au was fabricated using a nanolithography based lift-off process, heat treatment, and metal film sputtering. Composite electrode and backswitching poling resulted in 27% increase of d33 and 25% increase of dielectric constant, and we believe that this is attributed to regularly defined nano-domains and irreversible rhombohedral to monoclinic phase transition in crystal. The results indicate that nano-patterned composite electrode and backswitching poling has a great potential in domain engineering of relaxor single crystals for advanced devices. PMID:24170960

Placement of empty catheters for an HDR-emulating LDR prostate brachytherapy technique: comparison to standard intraoperative planning.

PubMed

Niedermayr, Thomas R; Nguyen, Paul L; Murciano-Goroff, Yonina R; Kovtun, Konstantin A; Neubauer Sugar, Emily; Cail, Daniel W; O'Farrell, Desmond A; Hansen, Jorgen L; Cormack, Robert A; Buzurovic, Ivan; Wolfsberger, Luciant T; O'Leary, Michael P; Steele, Graeme S; Devlin, Philip M; Orio, Peter F

2014-01-01

We sought to determine whether placing empty catheters within the prostate and then inverse planning iodine-125 seed locations within those catheters (High Dose Rate-Emulating Low Dose Rate Prostate Brachytherapy [HELP] technique) would improve concordance between planned and achieved dosimetry compared with a standard intraoperative technique. We examined 30 consecutive low dose rate prostate cases performed by standard intraoperative technique of planning followed by needle placement/seed deposition and compared them to 30 consecutive low dose rate prostate cases performed by the HELP technique. The primary endpoint was concordance between planned percentage of the clinical target volume that receives at least 100% of the prescribed dose/dose that covers 90% of the volume of the clinical target volume (V100/D90) and the actual V100/D90 achieved at Postoperative Day 1. The HELP technique had superior concordance between the planned target dosimetry and what was actually achieved at Day 1 and Day 30. Specifically, target D90 at Day 1 was on average 33.7 Gy less than planned for the standard intraoperative technique but was only 10.5 Gy less than planned for the HELP technique (p < 0.001). Day 30 values were 16.6 Gy less vs. 2.2 Gy more than planned, respectively (p = 0.028). Day 1 target V100 was 6.3% less than planned with standard vs. 2.8% less for HELP (p < 0.001). There was no significant difference between the urethral and rectal concordance (all p > 0.05). Placing empty needles first and optimizing the plan to the known positions of the needles resulted in improved concordance between the planned and the achieved dosimetry to the target, possibly because of elimination of errors in needle placement. Copyright © 2014 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Stressed out or subjective acquisition of competence – how do veterinary students see their curative work placement?

PubMed Central

Dilly, Marc; Tipold, Andrea; Geuenich, Katja

2016-01-01

Veterinary studies in Germany are regulated by the Veterinary Certification Act (TAppV). The practical part of the education consists of 1,170 hours, whereby up to 850 hours can be spent on the curative work placement. A curative work placement can result in physical and psychological stress in the sense of a professional overload. It is the aim of this study to find out in what areas and to what extent competence is acquired and psychological stress exists in students during their work placement. Veterinary students (n=142) from all German education institutes participated in a voluntary online-study based on Burnout Screening Scales (BOSS) as well as a questionnaire regarding the acquisition of competence and excessive stress during the work placement (FKÜP). The distribution of values for work placement related stress show that such work placement related stress is generally slightly increased (T=60) and lies above that of occupational stresses within the normal population. Work placement related physical complaints also show a significant slight increase (T=61). A value (T=42) within the normal range was determined for the resource values. Few of the students questioned considered themselves to be excessively stressed in favour of a high subjective acquisition of competences. The largest increase regarding the acquisition of competence was noted for the areas of animal handling/restraint and application and injection techniques. In the sense of a perceived excessive demand regarding practical capabilities the areas of emergency management, surgery and medication dispensation were mentioned. With regard to the load structure and the acquisition of competence by veterinary students during their work placement, more support of the individual and a balancing of teaching/learning goals would be desirable and represents a promising approach. PMID:26958657

Hollow mandrin facilitates external ventricular drainage placement.

PubMed

Heese, O; Regelsberger, J; Kehler, U; Westphal, M

2005-07-01

Placement of ventricular catheters is a routine procedure in neurosurgery. Ventricle puncture is done using a flexible ventricular catheter stabilised by a solid steel mandrin in order to improve stability during brain penetration. A correct catheter placement is confirmed after removing the solid steel mandrin by observation of cerebrospinal fluid (CSF) flow out of the flexible catheter. Incorrect placement makes further punctures necessary. The newly developed device allows CSF flow observation during the puncture procedure and in addition precise intracranial pressure (ICP) measurement. The developed mandrin is hollow with a blunt tip. On one side 4-5 small holes with a diameter of 0.8 mm are drilled corresponding exactly with the holes in the ventricular catheter, allowing CSF to pass into the hollow mandrin as soon as the ventricle is reached. By connecting a small translucent tube at the distal portion of the hollow mandrin ICP can be measured without loss of CSF. The system has been used in 15 patients with subarachnoid haemorrhage (SAH) or intraventricular haemeorrhage (IVH) and subsequent hydrocephalus. The new system improved the external ventricular drainage implantation procedure. In all 15 patients catheter placement was correct. ICP measurement was easy to perform immediately at ventricle puncture. In 4 patients at puncture no spontaneous CSF flow was observed, therefore by connecting a syringe and gentle aspiration of CSF correct placement was confirmed in this unexpected low pressure hydrocephalus. Otherwise by using the conventional technique further punctures would have been necessary. Advantages of the new technique are less puncture procedures with a lower risk of damage to neural structures and reduced risk of intracranial haemorrhages. Implantation of the ventricular catheter to far into the brain can be monitored and this complication can be overcome. Using the connected pressure monitoring tube an exact measurement of the opening intracranial pressure can be obtained performed without losing CSF.

Computed tomography assessment of lateral pedicle wall perforation by free-hand subaxial cervical pedicle screw placement.

PubMed

Wang, Yingsong; Xie, Jingming; Yang, Zhendong; Zhao, Zhi; Zhang, Ying; Li, Tao; Liu, Luping

2013-07-01

To present the technique of free-hand subaxial cervical pedicle screw (CPS) placement without using intra-operative navigating devices, and to investigate the crucial factors for safe placement and avoidance of lateral pedicle wall perforation, by measuring and classifying perforations with postoperative computed tomography (CT) scan. The placement of CPS has generally been considered as technically demanding and associated with considerable lateral wall perforation rate. For surgeons without access to navigation systems, experience of safe free-hand technique for subaxial CPS placement is especially valuable. A total of 214 consecutive traumatic or degenerative patients with 1,024 CPS placement using the free-hand technique were enrolled. In the operative process, the lateral mass surface was decorticated. Then a small curette was used to identify the pedicle entrance by touching the cortical bone of the medial pedicle wall. It was crucial to keep the transverse angle and make appropriate adjustment with guidance of the resistance of the thick medial cortical bone. The hand drill should be redirected once soft tissue breach was palpated by a slim ball-tip prober. With proper trajectory, tapping, repeated palpation, the 26-30 mm screw could be placed. After the procedure, the transverse angle of CPS trajectory was measured, and perforation of the lateral wall was classified by CT scan: grade 1, perforation of pedicle wall by screw placement, with the external edge of screw deviating out of the lateral pedicle wall equal to or less than 2 mm and grade 2, critical perforation of pedicle wall by screw placement, large than 2 mm. A total of 129 screws (12.64 %) were demonstrated as lateral pedicle wall perforation, of which 101 screws (9.86 %) were classified as grade 1, whereas 28 screws (2.73 %) as grade 2. Among the segments involved, C3 showed an obviously higher perforating rate than other (P < 0.05). The difference between the anatomical pedicle transverse angle and the screw trajectory angle was higher in patients of grade 2 perforation than the others. In the 28 screws of grade 2 perforation verified by axial CT, 26 screws had been palpated as abnormal during operation. However, only 19 out of the 101 screws of grade 1 perforation had shown palpation alarming signs during operation. The average follow-up was 36.8 months (range 5-65 months). There was no symptom and sign of neurovascular injuries. Two screws (0.20 %) were broken, and one screw (0.10 %) loosen. Placement of screw through a correct trajectory may lead to grade 1 perforation, which suggests transversal expansion and breakage of the thinner lateral cortex, probably caused by mismatching of the diameter of 3.5 mm screws and the tiny cancellous bone cavity of pedicle. Grade 1 perforation is deemed as relatively safe to the vertebral artery. Grade 2 perforation means obvious deviation of the trajectory angle of hand drill, which directly penetrates into the transverse foramen, and the risk of vertebral artery injury (VAI) or development of thrombi caused by the irregular blood flow would be much greater compared to grade 1 perforation. Moreover, there are two crucial maneuvers for increasing accuracy of screw placement: identifying the precise entry point using a curette or hand drill to touch the true entrance of the canal after decortication, and guiding CPS trajectory on axial plane by the resistant of thick medial wall.

Comparison of open reduction versus minimally invasive surgical approaches on screw position in canine sacroiliac lag-screw fixation.

PubMed

Déjardin, Loïc M; Marturello, Danielle M; Guiot, Laurent P; Guillou, Reunan P; DeCamp, Charles E

2016-07-19

To compare accuracy and consistency of sacral screw placement in canine pelves treated for sacroiliac luxation with open reduction and internal fixation (ORIF) or minimally invasive osteosynthesis (MIO) techniques. Unilateral sacroiliac luxations created experimentally in canine cadavers were stabilized with an iliosacral lag screw applied via ORIF or MIO techniques (n = 10/group). Dorsoventral and craniocaudal screw angles were measured using computed tomography multiplanar reconstructions in transverse and dorsal planes, respectively. Ratios between pilot hole length and sacral width (PL/SW-R) were obtained. Data between groups were compared statistically (p <0.05). Mean screw angles (±SD) were greater in ORIF specimens in both transverse (p <0.001) and dorsal planes (p <0.004). Mean PL/SW-R was smaller (p <0.001) in the ORIF group, yet was greater than 60%. While pilot holes exited the first sacral end-plate in three of 10 ORIF specimens, the spinal canal was not violated in either group. This study demonstrates that MIO fixation of canine sacroiliac luxations provides more accurate and consistent sacral screw placement than ORIF. With proper techniques, iatrogenic neurological damage can be avoided with both techniques. The PL /SW-R, which relates to safe screw fixation, also demonstrates that screw penetration of at least 60% of the sacral width is achievable regardless of surgical approach. These findings, along with the limited dissection needed for accurate sacral screw placement, suggest that MIO of sacroiliac luxations is a valid alternative to ORIF.

Nonlinear versus Ordinary Adaptive Control of Continuous Stirred-Tank Reactor

PubMed Central

Dostal, Petr

2015-01-01

Unfortunately, the major group of the systems in industry has nonlinear behavior and control of such processes with conventional control approaches with fixed parameters causes problems and suboptimal or unstable control results. An adaptive control is one way to how we can cope with nonlinearity of the system. This contribution compares classic adaptive control and its modification with Wiener system. This configuration divides nonlinear controller into the dynamic linear part and the static nonlinear part. The dynamic linear part is constructed with the use of polynomial synthesis together with the pole-placement method and the spectral factorization. The static nonlinear part uses static analysis of the controlled plant for introducing the mathematical nonlinear description of the relation between the controlled output and the change of the control input. Proposed controller is tested by the simulations on the mathematical model of the continuous stirred-tank reactor with cooling in the jacket as a typical nonlinear system. PMID:26346878

An adaptive control scheme for a flexible manipulator

NASA Technical Reports Server (NTRS)

Yang, T. C.; Yang, J. C. S.; Kudva, P.

1987-01-01

The problem of controlling a single link flexible manipulator is considered. A self-tuning adaptive control scheme is proposed which consists of a least squares on-line parameter identification of an equivalent linear model followed by a tuning of the gains of a pole placement controller using the parameter estimates. Since the initial parameter values for this model are assumed unknown, the use of arbitrarily chosen initial parameter estimates in the adaptive controller would result in undesirable transient effects. Hence, the initial stage control is carried out with a PID controller. Once the identified parameters have converged, control is transferred to the adaptive controller. Naturally, the relevant issues in this scheme are tests for parameter convergence and minimization of overshoots during control switch-over. To demonstrate the effectiveness of the proposed scheme, simulation results are presented with an analytical nonlinear dynamic model of a single link flexible manipulator.

Robust failure detection filters. M.S. Thesis

NASA Technical Reports Server (NTRS)

Sanmartin, A. M.

1985-01-01

The robustness of detection filters applied to the detection of actuator failures on a free-free beam is analyzed. This analysis is based on computer simulation tests of the detection filters in the presence of different types of model mismatch, and on frequency response functions of the transfers corresponding to the model mismatch. The robustness of detection filters based on a model of the beam containing a large number of structural modes varied dramatically with the placement of some of the filter poles. The dynamics of these filters were very hard to analyze. The design of detection filters with a number of modes equal to the number of sensors was trivial. They can be configured to detect any number of actuator failure events. The dynamics of these filters were very easy to analyze and their robustness properties were much improved. A change of the output transformation allowed the filter to perform satisfactorily with realistic levels of model mismatch.

Mode tuning of a simplified string instrument using time-dimensionless state-derivative control

NASA Astrophysics Data System (ADS)

Benacchio, Simon; Chomette, Baptiste; Mamou-Mani, Adrien; Finel, Victor

2015-01-01

In recent years, there has been a growing interest in smart structures, particularly in the field of musical acoustics. Control methods, initially developed to reduce vibration and damage, can be a good way to shift modal parameters of a structure in order to modify its dynamic response. This study focuses on smart musical instruments and aims to modify their radiated sound. This is achieved by controlling the modal parameters of the soundboard of a simplified string instrument. A method combining a pole placement algorithm and a time-dimensionless state-derivative control is used and quickly compared to a usual state control method. Then the effect of the mode tuning on the coupling between the string and the soundboard is experimentally studied. Controlling two vibration modes of the soundboard, its acoustic response and the damping of the third partial of the sound are modified. Finally these effects are listened in the radiated sound.

Attitude control/momentum management of the Space Station Freedom for large angle torque-equilibrium-attitude configurations

NASA Technical Reports Server (NTRS)

Parlos, Alexander G.; Sunkel, John W.

1990-01-01

An attitude-control and momentum-management (ACMM) system for the Space Station in a large-angle torque-equilibrium-attitude (TEA) configuration is developed analytically and demonstrated by means of numerical simulations. The equations of motion for a rigid-body Space Station model are outlined; linearized equations for an arbitrary TEA (resulting from misalignment of control and body axes) are derived; the general requirements for an ACMM are summarized; and a pole-placement linear-quadratic regulator solution based on scheduled gains is proposed. Results are presented in graphs for (1) simulations based on configuration MB3 (showing the importance of accounting for the cross-inertia terms in the TEA estimate) and (2) simulations of a stepwise change from configuration MB3 to the 'assembly complete' stage over 130 orbits (indicating that the present ACCM scheme maintains sufficient control over slowly varying Space Station dynamics).

Directed branch growth in aligned nanowire arrays.

PubMed

Beaudry, Allan L; LaForge, Joshua M; Tucker, Ryan T; Sorge, Jason B; Adamski, Nicholas L; Li, Peng; Taschuk, Michael T; Brett, Michael J

2014-01-01

Branch growth is directed along two, three, or four in-plane directions in vertically aligned nanowire arrays using vapor-liquid-solid glancing angle deposition (VLS-GLAD) flux engineering. In this work, a dynamically controlled collimated vapor flux guides branch placement during the self-catalyzed epitaxial growth of branched indium tin oxide nanowire arrays. The flux is positioned to grow branches on select nanowire facets, enabling fabrication of aligned nanotree arrays with L-, T-, or X-branching. In addition, a flux motion algorithm is designed to selectively elongate branches along one in-plane axis. Nanotrees are found to be aligned across large areas by X-ray diffraction pole figure analysis and through branch length and orientation measurements collected over 140 μm(2) from scanning electron microscopy images for each array. The pathway to guided assembly of nanowire architectures with controlled interconnectivity in three-dimensions using VLS-GLAD is discussed.

Identification and control of a multizone crystal growth furnace

NASA Technical Reports Server (NTRS)

Batur, C.; Sharpless, R. B.; Duval, W. M. B.; Rosenthal, B. N.; Singh, N. B.

1992-01-01

This paper presents an intelligent adaptive control system for the control of a solid-liquid interface of a crystal while it is growing via directional solidification inside a multizone transparent furnace. The task of the process controller is to establish a user-specified axial temperature profile and to maintain a desirable interface shape. Both single-input-single-output and multi-input-multi-output adaptive pole placement algorithms have been used to control the temperature. Also described is an intelligent measurement system to assess the shape of the crystal while it is growing. A color video imaging system observes the crystal in real time and determines the position and the shape of the interface. This information is used to evaluate the crystal growth rate, and to analyze the effects of translational velocity and temperature profiles on the shape of the interface. Creation of this knowledge base is the first step to incorporate image processing into furnace control.

Design and numerical evaluation of full-authority flight control systems for conventional and thruster-augmented helicopters employed in NOE operations

NASA Technical Reports Server (NTRS)

Perri, Todd A.; Mckillip, R. M., Jr.; Curtiss, H. C., Jr.

1987-01-01

The development and methodology is presented for development of full-authority implicit model-following and explicit model-following optimal controllers for use on helicopters operating in the Nap-of-the Earth (NOE) environment. Pole placement, input-output frequency response, and step input response were used to evaluate handling qualities performance. The pilot was equipped with velocity-command inputs. A mathematical/computational trajectory optimization method was employed to evaluate the ability of each controller to fly NOE maneuvers. The method determines the optimal swashplate and thruster input histories from the helicopter's dynamics and the prescribed geometry and desired flying qualities of the maneuver. Three maneuvers were investigated for both the implicit and explicit controllers with and without auxiliary propulsion installed: pop-up/dash/descent, bob-up at 40 knots, and glideslope. The explicit controller proved to be superior to the implicit controller in performance and ease of design.

Learning-based position control of a closed-kinematic chain robot end-effector

NASA Technical Reports Server (NTRS)

Nguyen, Charles C.; Zhou, Zhen-Lei

1990-01-01

A trajectory control scheme whose design is based on learning theory, for a six-degree-of-freedom (DOF) robot end-effector built to study robotic assembly of NASA hardwares in space is presented. The control scheme consists of two control systems: the feedback control system and the learning control system. The feedback control system is designed using the concept of linearization about a selected operating point, and the method of pole placement so that the closed-loop linearized system is stabilized. The learning control scheme consisting of PD-type learning controllers, provides additional inputs to improve the end-effector performance after each trial. Experimental studies performed on a 2 DOF end-effector built at CUA, for three tracking cases show that actual trajectories approach desired trajectories as the number of trials increases. The tracking errors are substantially reduced after only five trials.

Flatness-based control and Kalman filtering for a continuous-time macroeconomic model

NASA Astrophysics Data System (ADS)

Rigatos, G.; Siano, P.; Ghosh, T.; Busawon, K.; Binns, R.

2017-11-01

The article proposes flatness-based control for a nonlinear macro-economic model of the UK economy. The differential flatness properties of the model are proven. This enables to introduce a transformation (diffeomorphism) of the system's state variables and to express the state-space description of the model in the linear canonical (Brunowsky) form in which both the feedback control and the state estimation problem can be solved. For the linearized equivalent model of the macroeconomic system, stabilizing feedback control can be achieved using pole placement methods. Moreover, to implement stabilizing feedback control of the system by measuring only a subset of its state vector elements the Derivative-free nonlinear Kalman Filter is used. This consists of the Kalman Filter recursion applied on the linearized equivalent model of the financial system and of an inverse transformation that is based again on differential flatness theory. The asymptotic stability properties of the control scheme are confirmed.

The Effects of Surgical Factors on Postoperative Astigmatism in Patients Enrolled in the Infant Aphakia Treatment Study (IATS)

PubMed Central

Wall, Palak B.; Lee, Jason A.; Lynn, Michael; Lambert, Scott R.; Traboulsi, Elias I.

2015-01-01

Purpose To evaluate the impact of surgical factors such as incision type, number of sutures, and technique of closure on postoperative astigmatism in infants undergoing cataract extraction with or without intraocular lens implantation. Methods The IATS is a multicenter (n=12) clinical trial in which 114 infants with unilateral congenital cataracts were randomized to undergo cataract extraction with intraocular lens (IOL) placement or contact lens aphakic correction. Surgical videos were reviewed with regard to incision type and location, whether the incision was extended, the number of sutures placed, and technique of closure. Corneal astigmatism was measured using a handheld keratometer prior to surgery and at 1 year of age. Results Corneal astigmatism decreased from a mean of 1.92 D at baseline to 1.62 D at age 1 year in the CL group, but remained almost unchanged from 2.00 D to 2.09 D in the IOL group (p=0.023). There was no statistical difference between the amount of corneal astigmatism irrespective of incision type (p=0.214) and no increase in astigmatism with extension of the incision to facilitate IOL placement (p=0.849) at 1 year. The number of sutures and technique of closure did not influence the amount of astigmatism at 1 year. Conclusions At the age of one year following cataract extraction in infants, contact lens correction and the lack of IOL placement are associated with a significant decrease in postoperative corneal astigmatism compared to intraocular lens placement. No other surgical factors considered in this study had a statistically significant impact on corneal astigmatism. PMID:25266831

Upper quadrant port placement for robot-assisted renal surgery: implementation of the Floating Arm and the XL Protype.

PubMed

Totonchi, Samer; Elgin, Robert; Monahan, Michael; Johnston, William K

2014-08-01

Abstract Background and Purpose: Placement of the fourth arm (4th arm) in the lower quadrant (LQ) is commonly described for robot-assisted renal surgical procedures but has anatomic restrictions and limited ergonomics. An alternative, upper quadrant (UQ) location is desirable, but patient habitus and spacing may restrict robotic attachment. We investigate current trends in 4th arm port placement and propose an alternative method at attaching the robot-the "Floating Arm" (FLA). Robotic surgeons from the Endourological Society were surveyed. A 20-cm extra-long (XL Protype) da Vinci instrument was developed for the FLA technique. A dry lab allowed quantitative comparison of spacing and ranges of motion for standard da Vinci ports (dVP), bariatric dVP, telescoping dVP, and FLA. There were 108 respondents who participated. Half of the respondents avoid using the 4th arm (30% lack of need and 20% because of interference). The majority (90%) typically positions the 4th arm in the LQ, but many reported limitations in this location. Few (5%) place 4th arm in the UQ, while most (73%) have never heard of UQ placement. Existing techniques may increase shoulder height clearance but inversely shorten the working length of the instrument intracorporeally. Alternatively, the XL Protype significantly increased the shoulder length and maintained available working distances intracorporeally. Adjacent arm interference angle was essentially identical (27 degrees) for all ports except a greater range of movement for the XL Protype (35 degrees). Few surgeons are using an UQ positioning or use techniques to improve attachment of the 4th arm. The greatest freedom may be obtained by implementing the FLA, but this necessitates production of a longer instrument.

Successful Use of Orbital Atherectomy as an Adjunct in Treating Extensively Calcified Mesenteric Artery Lesions.

PubMed

Richard, Michele; Krol, Emilia; Dietzek, Alan

2016-10-01

To describe the use of orbital technique of atherectomy as an adjunct to successful angioplasty and stent placement of the superior mesenteric artery (SMA). The technique is demonstrated in a 68-year-old man with critical SMA stenosis. The SMA was cannulated with 0.014-in wire, but the lesion was highly stenotic and densely calcified and prevented the passage of even the smallest 1.5-mm balloon. Orbital atherectomy was thus performed with a 1.25-mm CSI crown. Balloon angioplasty was then possible with a 4 mm × 2 cm balloon followed by placement of a 7 mm × 22 mm balloon-mounted stent. The use of atherectomy as an adjunct to angioplasty and stenting in extensive, calcified SMA lesions supports the value of this technique to avoid a much larger and morbid open procedure. Published by Elsevier Inc.

Advantages and disadvantages of surgical placement of PD catheters with regard to other methods.

PubMed

Stegmayr, B

2006-01-01

Peritoneal dialysis is underused for various reasons. One reason may be problems with insertion of catheters for access. Another reason is the delayed start (break-in period) of about 2 weeks after operation. This review describes various approaches to the insertion of a peritoneal dialysis catheter. The optimal conditions to strive for are given as is an overview of various techniques. This article favours surgical placement while others might prefer other techniques. Described is the use a 3-purse string suture technique that allows immediate start of dialysis after catheter insertion both for acute dialysis indications as well as for acute start in chronic dialysis patients. A key to lesser complications is to establish a team devoted to the insertions rather than to allow various physicians to perform insertions as a training procedure. An optimal access is one of the important life lines for these patients.

Development of an MRI-Guided Intra-Prostatic Needle Placement System

DTIC Science & Technology

2011-07-01

and intra-operative imaging using techniques such as those described by Haker , et al. [18]. Target points for the needle insertion are selected... Haker , S., Fichtinger, G., Tem- pany, C.: Transperineal prostate biopsy under magnetic resonance image guid- ance: A needle placement accuracy study 26...clinically localized prostate cancer. Int J Radiat Oncol Biol Phys 42(3), 507–515 (1998) 9. DiMaio, S.P., Pieper, S., Chinzei, K., Hata, N., Haker , S.J

The clinical utility of testicular prosthesis placement in children with genital and testicular disorders

PubMed Central

2014-01-01

Testicular prosthesis placement is a useful important adjunctive reconstructive therapy for managing children with testicular loss or absence. Though these prostheses are functionless, experience has shown that they are extremely helpful in creating a more normal male body image and in preventing/relieving psychological stress in males with a missing testicle. With attention to details of implant technique, excellent cosmetic results can be anticipated in simulating a normal appearing scrotum. PMID:26816795

Percutaneous Pancreatic Stent Placement for Postoperative Pancreaticojejunostomy Stenosis: A Case Report

PubMed Central

Yang, Seung Koo

2016-01-01

Stenosis of the pancreatico-enteric anastomosis is one of the major complications of pancreaticoduodenectomy (PD). Endoscopic stent placement, has limited success rate as a nonsurgical treatment due to altered gastrointestinal anatomy. Percutaneous treatment is rarely attempted due to the technical difficulty in accessing the pancreatic duct. We reported a case of pancreaticojejunostomy stenosis after PD, in which a pancreatic stent was successfully placed using a rendezvous technique with a dual percutaneous approach. PMID:27587970

Outcomes after peritoneal dialysis catheter placement.

PubMed

Carpenter, Jennifer L; Fallon, Sara C; Swartz, Sarah J; Minifee, Paul K; Cass, Darrell L; Nuchtern, Jed G; Pimpalwar, Ashwin P; Brandt, Mary L

2016-05-01

The purpose of this study was to review surgical outcomes after elective placement of peritoneal dialysis (PD) catheters in children with end-stage renal disease. Children with PD catheters placed between February 2002 and July 2014 were retrospectively reviewed. Outcomes were catheter life, late (>30days post-op) complications (catheter malfunction, catheter malposition, infection), and re-operation rates. Comparison groups included laparoscopic versus open placement, age<2, and weight<10kg. Univariate and multivariate analysis were performed. One hundred sixteen patients had 173 catheters placed (122 open, 51 laparoscopic) with an average patient age of 9.7±6.3years. Mean catheter life was similar in the laparoscopic and open groups (581±539days versus 574±487days, p=0.938). The late complication rate was higher for open procedures (57% versus 37%, p=0.013). Children age<2 or weight<10kg had higher re-operation rates (64% versus 42%, p=0.014 and 73% versus 40%, p=0.001, respectively). Adjusted for age and weight, open technique remained a risk factor for late complications (OR 2.44, 95% CI 1.20-4.95) but not re-operation. Laparoscopic placement appears to reduce the rate of late complications in children who require PD dialysis catheters. Children <2years age or <10kg remain at risk for complications regardless of technique. Copyright © 2016 Elsevier Inc. All rights reserved.

Comminuted inferior pole fracture of patella can be successfully treated with rim-plate-augmented separate vertical wiring.

PubMed

Cho, Jae-Woo; Kim, Jinil; Cho, Won-Tae; Gujjar, Pranay H; Oh, Chang-Wug; Oh, Jong-Keon

2018-02-01

We present the surgical technique of rim-plate-augmented separate vertical wiring for comminuted inferior pole fracture of the patella and report the clinical outcomes. Between July 2013 and January 2016, 13 patients (7 male and 6 female) who were diagnosed with comminuted inferior pole fracture of the patella in preoperative computed tomography and underwent a minimum of 1 year of follow-up were enrolled in this study. Mean patient age was 57.7 years (range 28-72 years). All patients underwent open reduction and internal fixation by rim-plate-augmented separate vertical wiring. Bony union, complications, range of motion and Bostman score were the clinical outcomes. Bony union was achieved in all cases at an average of 10 weeks after surgery (range 8-12). There was no loss of reduction and fixative failure during follow-up. The average range of motion was 127° (range 120°-130°). The mean Bostman score at last follow-up was 29.6 points (range 27-30) and graded excellent in 12 patients. Rim-plate-augmented separate vertical wiring demonstrated secure fixation and favorable clinical outcomes. This study provides evidence for its effectiveness as a fixation method for treating displaced, comminuted inferior pole fracture of the patella.

Prosthodontic rehabilitation in patient with ectodermal dysplasia combining preprosthetic techniques: a case report.

PubMed

Pombo Castro, María; Luaces Rey, Ramón; Arenaz Búa, Jorge; Santana-Mora, Urbano; López-Cedrún Cembranos, José Luís

2013-10-01

Oral manifestations in ectodermal dysplasia include oligodontia, alveolar ridges hypoplasia, and others. Due to the special conditions in terms of unhealthy teeth and lack of bone, implant-supported rehabilitation seems to offer the most satisfactory outcome. A 27-year-old male diagnosed with ectodermal dysplasia was referred to our department for oral rehabilitation. Oral manifestations included oligodontia, maxillary and mandibular atrophy, mandibular alveolar ridge with knife-edge morphology, and conical teeth. Treatment planning consisted of a Le Fort I osteotomy with interpositional grafts, bilateral sinus lift, and placement of maxillary and mandibular inlay and onlay corticocancellous grafts, using autologous iliac crest bone. In the second surgery, all remaining teeth were removed and 11 endosteal implants were placed. Six months after implant placement, a bimaxillary fixed implant-supported prosthesis was delivered, maintaining a satisfactory esthetic and functional result after a 2-year follow-up. The use of combined preprosthetic techniques allows the placement of endosteal implants and a fixed implant-supported prosthesis in patients with oligodontia and ectodermal dysplasia, providing an esthetic and functional oral rehabilitation.

Fluid placement of fixated scrubber sludge to reduce surface subsidence and to abate acid mine drainage in abandoned underground coal mines

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

Meiers, R.J.; Golden, D.; Gray, R.

1995-12-31

Indianapolis Power and Light Company (IPL) began researching the use of fluid placement techniques of the fixated scrubber sludge (FSS) to reduce surface subsidence from underground coal mines to develop an economic alternative to low strength concrete grout. Abandoned underground coal mines surround property adjacent to IPL`s coal combustion by-product (CCBP) landfill at the Petersburg Generating Station. Landfill expansion into these areas is in question because of the high potential for sinkhole subsidence to develop. Sinkholes manifesting at the surface would put the integrity of a liner or runoff pond containment structure for a CCBP disposal facility at risk. Themore » fluid placement techniques of the FSS as a subsidence abatement technology was demonstrated during an eight week period in September, October, and November 1994 at the Petersburg Generating Station. The success of this technology will be determined by the percentage of the mine void filled, strength of the FSS placed, and the overall effects on the hydrogeologic environment. The complete report for this project will be finalized in early 1996.« less

Three-dimensional characterization of the effective second-order nonlinearity in periodically poled crystals

NASA Astrophysics Data System (ADS)

Holmgren, Stefan J.; Pasiskevicius, Valdas; Wang, Shunhua; Laurell, Fredrik

2003-09-01

A novel technique for characterization of the second-order nonlinearity in nonlinear crystals is presented. It utilizes group-velocity walk-off between femtosecond pulses in type II SHG to achieve three-dimensional resolution of the nonlinearity. The longitudinal and transversal spatial resolution can be set independently. The technique is especially useful for characterizing quasi-phase-matched nonlinear crystals, and it is demonstrated in potassium titanyl phosphate.

Structural response synthesis

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

Ozisik, H.; Keltie, R.F.

The open loop control technique of predicting a conditioned input signal based on a specified output response for a second order system has been analyzed both analytically and numerically to gain a firm understanding of the method. Differences between this method of control and digital closed loop control using pole cancellation were investigated as a follow up to previous experimental work. Application of the technique to diamond turning using a fast tool is also discussed.

Differences of standard values of Supersonic shear imaging and ARFI technique - in vivo study of testicular tissue.

PubMed

Trottmann, M; Rübenthaler, J; Marcon, J; Stief, C G; Reiser, M F; Clevert, D A

2016-01-01

To investigate the difference of standard values of Supersonic shear imaging (SSI) and Acoustic Radiation Force Impulse (ARFI) technique in the evaluation of testicular tissue stiffness in vivo. 58 healthy male testes were examined using B-mode sonography and ARFI and SSI. B-mode sonography was performed in order to scan the testis for pathologies followed by performance of real-time elastography in three predefined areas (upper pole, central portion and lower pole) using the SuperSonic® Aixplorer ultrasound device (SuperSonic Imagine, Aix-en-Provence, France). Afterwards a second assessment of the same testicular regions by elastography followed using the ARFI technique of the Siemens Acuson 2000™ ultrasound device (Siemens Health Care, Germany). Values of shear wave velocity were described in m/s. Parameters of elastography techniques were compared using paired sample t-test. The values of SSI were all significantly higher in all measured areas compared to ARFI (p < 0.001 to p = 0.015). Quantitatively there was a higher mean SSI wave velocity value of 1,1 compared to 0.8 m/s measured by ARFI. SSI values are significantly higher than ARFI values when measuring the stiffness of testicular tissue and should only be compared with caution.

Alterations in aerobic energy expenditure and neuromuscular function during a simulated cross-country skiathlon with the skating technique.

PubMed

Fabre, Nicolas; Mourot, Laurent; Zoppirolli, Chiara; Andersson, Erik; Willis, Sarah J; Holmberg, Hans-Christer

2015-04-01

Here, we tested the hypothesis that aerobic energy expenditure (AEE) is higher during a simulated 6-km (2 loops of 3-km each) "skiathlon" than during skating only on a treadmill and attempted to link any such increase to biomechanical and neuromuscular responses. Six elite male cross-country skiers performed two pre-testing time-trials (TT) to determine their best performances and to choose an appropriate submaximal speed for collection of physiological, biomechanical and neuromuscular data during two experimental sessions (exp). Each skier used, in randomized order, either the classical (CL) or skating technique (SK) for the first 3-km loop, followed by transition to the skating technique for the second 3-km loop. Respiratory parameters were recorded continuously. The EMG activity of the triceps brachii (TBr) and vastus lateralis (VLa) muscles during isometric contractions performed when the skiers were stationary (i.e., just before the first loop, during the transition, and after the second loop); their corresponding activity during dynamic contractions; and pole and plantar forces during the second loop were recorded. During the second 3-km of the TT, skating speed was significantly higher for the SK-SK than CL-SK. During this second loop, AEE was also higher (+1.5%) for CL-SKexp than SK-SKexp, in association with higher VLa EMG activity during both isometric and dynamic contractions, despite no differences in plantar or pole forces, poling times or cycle rates. Although the underlying mechanism remains unclear, during a skiathlon, the transition between the sections of classical skiing and skating alters skating performance (i.e., skiing speed), AEE and neuromuscular function. Copyright © 2015 Elsevier B.V. All rights reserved.

Gait models and mechanical energy in three cross-country skiing techniques.

PubMed

Pellegrini, Barbara; Zoppirolli, Chiara; Bortolan, Lorenzo; Zamparo, Paola; Schena, Federico

2014-11-01

Fluctuations in mechanical energy of the body center of mass (COM) have been widely analyzed when investigating different gaits in human and animal locomotion. We applied this approach to estimate the mechanical work in cross-country skiing and to identify the fundamental mechanisms of this particular form of locomotion. We acquired movements of body segments, skis, poles and plantar pressures for eight skiers while they roller skied on a treadmill at 14 km h(-1) and a 2 deg slope using three different techniques (diagonal stride, DS; double poling, DP; double poling with kick, DK). The work associated with kinetic energy (KE) changes of COM was not different between techniques; the work against gravity associated with potential energy (PE) changes was higher for DP than for DK and was lowest for DS. Mechanical work against the external environment was 0.87 J m(-1) kg(-1) for DS, 0.70 J m(-1) kg(-1) for DP and 0.79 J m(-1) kg(-1) for DK. The work done to overcome frictional forces, which is negligible in walking and running, was 17.8%, 32.3% and 24.8% of external mechanical work for DS, DP and DK, respectively. The pendulum-like recovery (R%) between PE and KE was ~45%, ~26% and ~9% for DP, DK and DS, respectively, but energy losses by friction are not accounted for in this computation. The pattern of fluctuations of PE and KE indicates that DS can be described as a 'grounded running', where aerial phases are substituted by ski gliding phases, DP can be described as a pendular gait, whereas DK is a combination of both. © 2014. Published by The Company of Biologists Ltd.

Patella Fracture Fixation with Suture and Wire: you Reap what you Sew

PubMed Central

Egol, Kenneth; Howard, Daniel; Monroy, Alexa; Crespo, Alexander; Tejwani, Nirmal; Davidovitch, Roy

2014-01-01

Introduction Operative fixation of displaced inferior pole patella fractures has now become the standard of care. This study aims to quantify clinical, radiographic and functional outcomes, as well as identify complications in a cohort of patients treated with non-absorbable braided suture fixation for inferior pole patellar fractures. These patients were then compared to a control group of patients treated for mid-pole fractures with K-wires or cannulated screws with tension band wiring. Methods In this IRB approved study, we identified a cohort of patients who were diagnosed and treated surgically for a displaced patella fracture. Demographic, injury, and surgical information were recorded. All patients were treated with a standard surgical technique utilizing non-absorbable braided suture woven through the patellar tendon and placed through drill holes to achieve reduction and fracture fixation. All patients were treated with a similar post-operative protocol and followed up at standard intervals. Data were collected concurrently at follow up visits. For purpose of comparison, we identified a control cohort with middle third patella fractures treated with either k-wires or cannulated screws and tension band technique. Patients were followed by the treating surgeon at regular follow-up intervals. Outcomes included self-reported function and knee range of motion compared to the uninjured side. Results Forty-nine patients with 49 patella fractures identified retrospectively were treated over 9 years. This cohort consisted of 31 females (63.3%) and 18 males (36.7%) with an average age of 57.1 years (range 26 - 88 years). Patients had an average BMI of 26.48 (range 19 - 44.08). Thirteen patients with inferior pole fractures underwent suture fixation and 36 patients with mid-pole fractures underwent tension band fixation (K-wire or cannulated screws with tension band). In the suture cohort, one fracture failed open repair (7.6%), which was revised again with sutures and progressed to union. Of the 36 fractures repaired with a tension band fixation, 11 underwent secondary surgery due to hardware pain or fixation failure (30.6%). At one year, no difference was seen in knee range of motion between cohorts. All fractures healed radiographically. Those patients who required reoperation or removal of hardware had significantly diminished range of motion about their injured knee (p > 0.005). Conclusions Patients who sustain inferior pole patella fractures have limited options for fracture fixation. Suture repair is clinically acceptable, yielding similar results to patella fractures repaired with metal implants. Importantly, patients undergoing suture repair appear to have fewer hardware related postoperative complications than those receiving wire fixation for midpole fractures. PMID:25328461

Patella fracture fixation with suture and wire: you reap what you sew.

PubMed

Egol, Kenneth; Howard, Daniel; Monroy, Alexa; Crespo, Alexander; Tejwani, Nirmal; Davidovitch, Roy

2014-01-01

Operative fixation of displaced inferior pole patella fractures has now become the standard of care. This study aims to quantify clinical, radiographic and functional outcomes, as well as identify complications in a cohort of patients treated with non-absorbable braided suture fixation for inferior pole patellar fractures. These patients were then compared to a control group of patients treated for mid-pole fractures with K-wires or cannulated screws with tension band wiring. In this IRB approved study, we identified a cohort of patients who were diagnosed and treated surgically for a displaced patella fracture. Demographic, injury, and surgical information were recorded. All patients were treated with a standard surgical technique utilizing non-absorbable braided suture woven through the patellar tendon and placed through drill holes to achieve reduction and fracture fixation. All patients were treated with a similar post-operative protocol and followed up at standard intervals. Data were collected concurrently at follow up visits. For purpose of comparison, we identified a control cohort with middle third patella fractures treated with either k-wires or cannulated screws and tension band technique. Patients were followed by the treating surgeon at regular follow-up intervals. Outcomes included self-reported function and knee range of motion compared to the uninjured side. Forty-nine patients with 49 patella fractures identified retrospectively were treated over 9 years. This cohort consisted of 31 females (63.3%) and 18 males (36.7%) with an average age of 57.1 years (range 26-88 years). Patients had an average BMI of 26.48 (range 19-44.08). Thirteen patients with inferior pole fractures underwent suture fixation and 36 patients with mid-pole fractures underwent tension band fixation (K-wire or cannulated screws with tension band). In the suture cohort, one fracture failed open repair (7.6%), which was revised again with sutures and progressed to union. Of the 36 fractures repaired with a tension band fixation, 11 underwent secondary surgery due to hardware pain or fixation failure (30.6%). At one year, no difference was seen in knee range of motion between cohorts. All fractures healed radiographically. Those patients who required reoperation or removal of hardware had significantly diminished range of motion about their injured knee (p > 0.005). Patients who sustain inferior pole patella fractures have limited options for fracture fixation. Suture repair is clinically acceptable, yielding similar results to patella fractures repaired with metal implants. Importantly, patients undergoing suture repair appear to have fewer hardware related postoperative complications than those receiving wire fixation for midpole fractures.

Upper limb joint kinetics of three sitting pivot wheelchair transfer techniques in individuals with spinal cord injury.

PubMed

Kankipati, Padmaja; Boninger, Michael L; Gagnon, Dany; Cooper, Rory A; Koontz, Alicia M

2015-07-01

Repeated measures design. This study compared the upper extremity (UE) joint kinetics between three transfer techniques. Research laboratory. Twenty individuals with spinal cord injury performed three transfer techniques from their wheelchair to a level tub bench. Two of the techniques involved a head-hips method with leading hand position close (HH-I) and far (HH-A) from the body, and the third technique with the trunk upright (TU) and hand far from body. Motion analysis equipment recorded upper body movements and force sensors recorded their hand and feet reaction forces during the transfers. Several significant differences were found between HH-A and HH-I and TU and HH-I transfers indicating that hand placement was a key factor influencing the UE joint kinetics. Peak resultant hand, elbow, and shoulder joint forces were significantly higher for the HH-A and TU techniques at the trailing arm (P < 0.036) and lower at the leading arm (P < 0.021), compared to the HH-I technique. Always trailing with the same arm if using HH-A or TU could predispose that arm to overuse related pain and injuries. Technique training should focus on initial hand placement close to the body followed by the amount of trunk flexion needed to facilitate movement.

Factors affecting Cook Gunther Tulip and Cook Celect inferior vena cava filter retrieval success.

PubMed

Glocker, Roan J; Novak, Zdenek; Matthews, Thomas C; Patterson, Mark A; Jordan, William D; Pearce, Benjamin J; Passman, Marc A

2014-01-01

Success rates vary for the retrieval of inferior vena cava filters (IVCFs). The optimal retrieval time and factors influencing retrieval success remain unproven. This study aims to determine optimal time and evaluate factors related to successful IVCF retrieval. An institutional prospectively maintained database was reviewed for all IVCF retrieval attempts from 2006 to 2012. Patient demographics, comorbidities, indications for procedure, placement technique, IVCF type, presence of angulation, and time to retrieval were evaluated with respect to success or failure of retrieval. Statistical analyses (t-test, χ(2), correlations, and Kaplan-Meier plots) were performed comparing successful and unsuccessful retrievals. Of 121 attempted IVCF retrievals, 92 (76%) were successful and 29 (24%) were unsuccessful. There were no significant differences between the successful and unsuccessful attempts in terms of patient demographics, comorbidities, indications for procedure, placement technique, or IVCF type, which included 93 Celect (77%) and 28 Gunther Tulip (23%). Time since IVCF placement was significantly different (P = .025) between the successful and unsuccessful retrieval groups (medians were 105 [7-368] and 162 [43-379] days, respectively). Time since IVCF placement greater than 117 days correlated significantly with unsuccessful IVCF retrieval (R = 0.218; P = .017; odds ratio, 2.88; P = .02). Angulation greater than 20 degrees on anteroposterior radiograph was noted in seven of 29 (24%) unsuccessful retrievals compared with seven of 92 (8%) successful retrievals and was significant (P = .012). Cook Gunther Tulip and Celect IVCF retrieval is most likely to be successful within 3 to 4 months of placement. Unsuccessful retrieval attempts are more likely to occur when IVCF position is angulated. Copyright © 2014 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Inserting pedicle screws in the upper thoracic spine without the use of fluoroscopy or image guidance. Is it safe?

PubMed

Schizas, Constantin; Theumann, Nicolas; Kosmopoulos, Victor

2007-05-01

Several studies have looked at accuracy of thoracic pedicle screw placement using fluoroscopy, image guidance, and anatomical landmarks. To our knowledge the upper thoracic spine (T1-T6) has not been specifically studied in the context of screw insertion and placement accuracy without the use of either image guidance or fluoroscopy. Our objective was to study the accuracy of upper thoracic screw placement without the use of fluoroscopy or image guidance, and report on implant related complications. A single surgeon inserted 60 screws in 13 consecutive non-scoliotic spine patients. These were the first 60 screws placed in the high thoracic spine in our institution. The most common diagnosis in our patient population was trauma. All screws were inserted using a modified Roy-Camille technique. Post-operative axial computed tomography (CT) images were obtained for each patient and analyzed by an independent senior radiologist for placement accuracy. Implant related complications were prospectively noted. No pedicle screw misplacement was found in 61.5% of the patients. In the remaining 38.5% of patients some misplacements were noted. Fifty-three screws out of the total 60 implanted were placed correctly within all the pedicle margins. The overall pedicle screw placement accuracy was 88.3% using our modified Roy-Camille technique. Five medial and two lateral violations were noted in the seven misplaced screws. One of the seven misplaced screws was considered to be questionable in terms of pedicle perforation. No implant related complications were noted. We found that inserting pedicle screws in the upper thoracic spine based solely on anatomical landmarks was safe with an accuracy comparable to that of published studies using image-guided navigation at the thoracic level.

Fiducial marker placement via conventional or electromagnetic navigation bronchoscopy (ENB): an interdisciplinary approach to the curative management of lung cancer.

PubMed

Hagmeyer, Lars; Priegnitz, Christina; Kocher, Martin; Schilcher, Burkhart; Budach, Wilfried; Treml, Marcel; Stieglitz, Sven; Randerath, Winfried

2016-05-01

Conventional and electromagnetic navigation bronchoscopy (ENB) is generally used as a diagnostic tool in suspicious pulmonary nodules. The use of this technique for the placement of fiducial markers in patients with inoperable but early-stage lung cancer could present an innovative approach enabling risk-reduced therapy. We present seven clinical cases where conventional bronchoscopy and ENB were used as part of an experimental interdisciplinary approach to clinical management and therapy planning. In each case, we analyzed the clinical indication, endoscopic procedures and post-interventional outcome. In six patients (three females, three males) with peripheral non-small cell lung cancer (NSCLC), stage cT1cN0cM0, surgery and conventional stereotactic radiation therapy was not possible because of end-stage chronic obstructive pulmonary disease. ENB was used for fiducial marker placement prior to cyberknife radiotherapy. No procedure-related complications were observed. Complete remission could be achieved in four cases, partial remission in two cases and no relevant complications induced by radiotherapy were observed. In one male patient, an endoluminal relapse in the right lower lobe was diagnosed following a right upper lobe resection for a NSCLC. The tumor could not be clearly identified by computerized tomography, so that the bronchoscopic placement of a fiducial marker in the tumor was performed in order to allow stereotactic radiochemotherapy, by which complete remission could be achieved. Fiducial marker placement may be an interesting bronchoscopic technique in the interdisciplinary therapeutic approach to inoperable early-stage lung cancer. In the described cases, therapy planning was successful and no procedure-related complications were observed. © 2014 John Wiley & Sons Ltd.

Ultrasound-guided thermocouple placement for cryosurgery.

PubMed

Abramovits, W; Pruiksma, R; Bose, S

1996-09-01

Although cryosurgical methods have high cure rates, imprecise estimates of both skin lesion depth and destructive temperature front location result in subjective technique in skin malignancy treatments. We evaluated the possibility of newer ultrasound equipment to assist in the precise placement of thermocouples in human skin. DermaScan C ver. 3 ultrasonographic equipment fitted with a sharp focus probe with a frequency of 20 MHz and a scan length of 12.1 mm was used to locate thermocouples with 27- and 30-gauge needles. We successfully and reproducibly located thermocouples and thin needles, and accurately measured their distance from the skin surface. Ultrasound is a useful method for the accurate placement of thermocouples, and needles as thin as 30 gauge for monitoring in cryosurgery.

A Preliminary Report on Combined Penoscrotal and Perineal Approach for Placement of Penile Prosthesis with Corporal Fibrosis

PubMed Central

Brusky, John P.; Tran, Viet Q.; Rieder, Jocelyn M.; Aboseif, Sherif R.

2008-01-01

Purpose. This paper aims at describing the combined penoscrotal and perineal approach for placement of penile prosthesis in cases of severe corporal fibrosis and scarring. Materials and methods. Three patients with extensive corporal fibrosis underwent penile prosthesis placement via combined penoscrotal and perineal approach from 1997 to 2006. Follow-up ranged from 15 to 129 months. Results. All patients underwent successful implantation of semirigid penile prosthesis. There were no short- or long-term complications. Conclusions. Results on combined penoscrotal and perineal approach to penile prosthetic surgery in this preliminary series of patients suggest that it is a safe technique and increases the chance of successful outcome in the surgical management of severe corporal fibrosis. PMID:19043562

CT-Guided Placement of a Drainage Catheter Within a Pelvic Abscess Using a Transsacral Approach

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

Iguchi, Toshihiro; Asami, Shinya; Kubo, Shinichiro

2007-11-15

A 66-year-old man underwent CT-guided drainage catheter placement within a pelvic abscess with a diameter of 46 mm. We performed the drainage by a transsacral approach because it was considered the safest and most feasible approach. An 8G bone marrow biopsy needle was used to penetrate the sacrum to create a path for subsequent drainage catheter insertion. After withdrawal of the biopsy needle, a 6 Fr catheter was advanced into the abscess cavity through the path using the Seldinger technique. Except for bearable pain, no procedure-related complications occurred. Twenty-nine days after the placement, the catheter was withdrawn safely and themore » abscess cavity had shrunk remarkably.« less

Force interaction and 3D pole movement in double poling.

PubMed

Stöggl, T; Holmberg, H-C

2011-12-01

The aim of this study was to analyze double poling using combined kinetic and 3D kinematic analysis at high skiing speeds as regards pole force components, pole angles and pole behavior during the poling and swing phase. The hypothesis was that a horizontal pole force is more predictive for maximal skiing speed (V(max)) than the resultant pole force. Sixteen elite skiers performed a double-poling V(max) test while treadmill roller skiing. Pole forces and 3D kinematics of pole movement at a speed of 30 km/h were analyzed and related to V(max). The duration of the "preparation phase" showed the strongest relationship with V(max) (r=0.87, P<0.001). Faster skiers generated longer cycle lengths with longer swing and poling times, had less inclined pole angles at pole plant and a later peak pole force. Horizontal pole forces were not more highly related to V(max) compared with the resultant pole force. Impact force was not related to V(max). At high skiing speeds, skiers should aim to combine high pole forces with appropriate timing of pole forces and appropriate pole and body positions during the swing and poling phase. The emphasis in training should be on the development of specific strength capacities for pole force production and the utilization of these capacities in double-poling training sessions. © 2011 John Wiley & Sons A/S.

Energy cost and pole forces during Nordic walking under different surface conditions.

PubMed

Schiffer, Thorsten; Knicker, Axel; Dannöhl, Regine; Strüder, Heiko K

2009-03-01

The purpose of the study was to identify the effect of three different surfaces on energy consumption and the forces acting on the walking poles during ground contact in Nordic walking (NW). Thirteen female NW instructors (age = 26 +/- 4 yr, weight = 58.5 +/- 4.2 kg, height = 168.1 +/- 4.6 cm) volunteered in the study. The subjects walked a distance of 1200 m at a controlled, constant speed of 2.2 m x s(-1) on each of a concrete surface (C), an artificial athletics track (A), and a naturally grown soccer lawn (G). They used NW poles with inbuilt strain gauge force transducers to measure ground reaction forces acting along the long axes of the poles. Oxygen uptake, capillary blood lactate (La), HR, and RPE were measured before and after the tests. Impact forces, maximum forces, force rates during ground contact identified from the registered force time histories, displayed significant differences related to the surface conditions. However, force time integrals did not show surface-related differences. Relative oxygen consumption showed significant differences between NW on C and on G whereas no surface-related differences could be identified between the surface conditions for the parameters La, HR, and RPE. Our data indicate that the impulse that is generated by the poles on the subjects is identical between the varying surfaces. Because there are differences for the oxygen uptake between C and G, the main regulator for the propulsion must be the musculature of the lower extremities. The work of the upper extremities seems to be a luxury effort for Nordic walkers with a proper technique.

The Cantor-Bendixson Rank of Certain Bridgeland-Smith Stability Conditions

NASA Astrophysics Data System (ADS)

Aulicino, David

2018-01-01

We provide a novel proof that the set of directions that admit a saddle connection on a meromorphic quadratic differential with at least one pole of order at least two is closed, which generalizes a result of Bridgeland and Smith, and Gaiotto, Moore, and Neitzke. Secondly, we show that this set has finite Cantor-Bendixson rank and give a tight bound. Finally, we present a family of surfaces realizing all possible Cantor-Bendixson ranks. The techniques in the proof of this result exclusively concern Abelian differentials on Riemann surfaces, also known as translation surfaces. The concept of a "slit translation surface" is introduced as the primary tool for studying meromorphic quadratic differentials with higher order poles.

Magnetic precipitate separation for Ni plating waste liquid using HTS bulk magnets

NASA Astrophysics Data System (ADS)

Oka, T.; Kimura, T.; Mimura, D.; Fukazawa, H.; Fukui, S.; Ogawa, J.; Sato, T.; Ooizumi, M.; Yokoyama, K.; Tsujimura, M.; Terasawa, T.

2013-01-01

The magnetic separation experiment for recycling the nickel-bearing precipitates in the waste liquid from the electroless plating processes has been practically conducted under the high gradient magnetic separation technique with use of the face-to-face HTS bulk magnet system. A couple of facing magnetic poles containing Sm123 bulk superconductors were activated through the pulsed field magnetization process to 1.86 T at 38 K and 2.00 T at 37 K, respectively. The weakly magnetized metallic precipitates of Ni crystals and Ni-P compounds deposited from the waste solution after heating it and pH controlling. The high gradient magnetic separation technique was employed with the separation channels filled with the stainless steel balls with dimension of 1 and 3 mm in diameter, which periodically moved between and out of the facing magnetic poles. The Ni-bearing precipitates were effectively attracted to the magnetized ferromagnetic balls. We have succeeded in obtaining the separation ratios over 90% under the flow rates less than 1.35 L/min.

Mainstreaming: Sharing Ideas, Strategies, Materials, Techniques.

ERIC Educational Resources Information Center

Hillside School, Cushing, OK.

The manual provides teaching approaches based on a model of least to highest modification of instruction, which may be used for a continuum of special education placements ranging from regular classroom through hospital settings. The first section on adaptive techniques (requiring the least modification) includes suggestions to adjust time for…

Effect of Different Composite Restorations on the Cuspal Deflection of Premolars Restored with Different Insertion Techniques- An In vitro Study.

PubMed

Singhal, Sakshi; Gurtu, Anuraag; Singhal, Anurag; Bansal, Rashmi; Mohan, Sumit

2017-08-01

This study was conducted to assess the effect of different composite materials on the cuspal deflection of premolars restored with bulk placement of resin composite in comparison to horizontal incremental placement and modified tangential incremental placement. The aim of this study was to evaluate the cuspal deflection caused by different composite materials when different insertion techniques were used. Two different composite materials were used that is Tetric N Ceram (Ivoclar Vivadent marketing, India) and SonicFill TM (Kerr Sybron Dental). Forty standardized Mesio-Occluso-Distal (MOD) preparations were prepared on maxillary first premolars. Each group was divided according to composite insertion technique (n=10), as follows: Group I - bulk insertion using Tetric N Ceram, Group II - Horizontal incremental insertion technique using Tetric N Ceram, Group III- Modified tangential incremental technique using Tetric N Ceram, and Group IV- bulk insertion using SonicFill TM . Preparations were acid-etched, and bonded with adhesive resin to provide micro mechanical attachment before restoration using a uniform etching and bonding protocol in all the groups. All groups received the same total photo-polymerization time. Cuspal deflection was measured during the restorative procedure using customized digital micrometer assembly. One-way ANOVA test was applied for the analysis of significant difference between the groups, p-value less than 0.05 was considered statistically significant. The average cuspal deflections for the different groups were as follows: Group I 0.045±0.018, Group II 0.029±0.009, Group III 0.018±0.005 and Group IV 0.017±0.004. The intergroup comparison revealed statistically significant difference. A measurable amount of cuspal deflection was present in all the four studied groups. In general, bulkfill restoration technique with conventional composite showed significantly highest cusp deflection. There were no significant differences in cuspal deflection among sonicFill TM and modified tangential incremental insertion techniques.

Optimal Trajectories Generation in Robotic Fiber Placement Systems

NASA Astrophysics Data System (ADS)

Gao, Jiuchun; Pashkevich, Anatol; Caro, Stéphane

2017-06-01

The paper proposes a methodology for optimal trajectories generation in robotic fiber placement systems. A strategy to tune the parameters of the optimization algorithm at hand is also introduced. The presented technique transforms the original continuous problem into a discrete one where the time-optimal motions are generated by using dynamic programming. The developed strategy for the optimization algorithm tuning allows essentially reducing the computing time and obtaining trajectories satisfying industrial constraints. Feasibilities and advantages of the proposed methodology are confirmed by an application example.

Guided implant surgery with modification of the technique involving the raising of a semicircular miniflap: A preliminary study

PubMed Central

Viña, José; Maestre, Laura; Peñarrocha, David; Balaguer, José

2012-01-01

Objective: An evaluation is made of pain, swelling and peri-implant attached mucosal width after implant-based rehabilitation involving guided surgery and a modification of the technique with the raising of a semicircular miniflap, in single and partial replacements. Study design: A case-control study was carried out. The study group consisted of 12 patients with the placement of 19 implants using a guided surgery and miniflap technique. The control group consisted of 12 patients with the placement of 22 implants using the conventional technique. Each patient scored postoperative swelling and pain by means of a visual analog scale (VAS). Attached vestibular mucosa width was evaluated 12 weeks after implant placement. Results: Twelve operations were carried out in each group. Immediate aesthetics were established for all implants of the study group. One implant failed in each group. Maximum pain was recorded after 6 hours in both groups (mean VAS score 4 and 4.9 in the study and control group, respectively). Maximum swelling was recorded after 24 hours (mean VAS score 2.5) in the study group and on the second day (mean VAS score 3.4) in the control group. The mean attached vestibular mucosa width was 2.9 mm in the study group and 3.2 mm in the control group. Conclusion: In this preliminary study, guided implant surgery with a semicircular miniflap in single and partial replacements resulted in slightly less postoperative pain and swelling than with the conventional implant technique. The attached vestibular mucosa width was greater in the control group, though the differences were very small. Key words:Guided surgery, flapless surgery, miniflap, peri-implant mucosa. PMID:22549666

Adjuvant Hepatic Arterial Infusion Chemotherapy After Resection for Pancreatic Cancer Using Coaxial Catheter-Port System Compared with Conventional System.

PubMed

Hashimoto, Aya; Tanaka, Toshihiro; Sho, Masayuki; Nishiofuku, Hideyuki; Masada, Tetsuya; Sato, Takeshi; Marugami, Nagaaki; Anai, Hiroshi; Sakaguchi, Hiroshi; Kanno, Masatoshi; Tamamoto, Tetsuro; Hasegawa, Masatoshi; Nakajima, Yoshiyuki; Kichikawa, Kimihiko

2016-06-01

Previous reports have shown the effectiveness of adjuvant hepatic arterial infusion chemotherapy (HAIC) in pancreatic cancer. However, percutaneous catheter placement is technically difficult after pancreatic surgery. The purpose of this study was to evaluate the feasibility and outcome of HAIC using a coaxial technique compared with conventional technique for postoperative pancreatic cancer. 93 consecutive patients who received percutaneous catheter-port system placement after pancreatectomy were enrolled. In 58 patients from March 2006 to August 2010 (Group A), a conventional technique with a 5-Fr indwelling catheter was used and in 35 patients from September 2010 to September 2012 (Group B), a coaxial technique with a 2.7-Fr coaxial catheter was used. The overall technical success rates were 97.1 % in Group B and 86.2 % in Group A. In cases with arterial tortuousness and stenosis, the success rate was significantly higher in Group B (91.7 vs. 53.8 %; P = 0.046). Fluoroscopic and total procedure times were significantly shorter in Group B: 14.7 versus 26.7 min (P = 0.001) and 64.8 versus 80.7 min (P = 0.0051), respectively. No differences were seen in the complication rate. The 1 year liver metastasis rates were 9.9 % using the conventional system and 9.1 % using the coaxial system (P = 0.678). The overall median survival time was 44 months. There was no difference in the survival period between two systems (P = 0.312). The coaxial technique is useful for catheter placement after pancreatectomy, achieving a high success rate and reducing fluoroscopic and procedure times, while maintaining the safety and efficacy for adjuvant HAIC in pancreatic cancer.

A coil placement technique to treat intracranial aneurysm with incorporated artery.

PubMed

Luo, Chao-Bao; Chang, Feng-Chi; Lin, Chung-Jung; Guo, Wan-Yuo

2018-03-01

Endovascular coil embolization is an accepted treatment option for intracranial aneurysms. However, the coiling of aneurysms with an incorporated artery (IA) poses a high risk of IA occlusion. Here we report our experience of endovascular coil placement using a technique that avoids IA occlusion in aneurysms with IAs. Over a 6-year period, 185 patients harboring 206 intracranial aneurysms underwent endosaccular coiling. Forty-two of these patients with 45 aneurysms were treated by coil placement to avoid IAs occlusion. We assessed the anatomy of the aneurysms and IAs, technical feasibility of the procedure, and degree of aneurysm occlusion. Clinical and angiographic outcomes were assessed as well. Aneurysms were located in the supra-clinoid intracranial internal carotid artery (n = 24), anterior cerebral artery (n = 6), middle cerebral artery (n = 7), and vertebrobasilar artery (n = 8). The IA was at the aneurysm neck in 34 patients, body in 10, and dome in 1. Immediate post-coiling angiogram showed preservation of blood flow through the IA in all aneurysms. Coil compaction with aneurysmal regrowth was found in 7 of 36 patients having follow-up conventional angiography. One patient had an IA territory infarction after embolization. All 42 patients were followed up (mean: 21 months) and showed no re-bleeding. This technique is effective and safe in managing intracranial aneurysms with IAs. Although aneurysmal recurrence may occur in some aneurysms because of insufficient coiling, this technique is simpler to perform and requires less skill than other techniques. It can be an alternative option for treating some selected intracranial aneurysms with IAs. Copyright © 2017. Published by Elsevier Taiwan LLC.

Tonian paleomagnetism of the red beds of Madiyi Formation, lower Banxi Group in South China: implications for pre-Sturtian climate, Rodinia reconstruction and true polar wander

NASA Astrophysics Data System (ADS)

Hanbiao, X.; Zhang, S.; Xiao, Q.; Li, H.; Chang, L.; Fu, H.; Liu, R.

2017-12-01

We present a new Tonian paleomagnetic pole from the red beds of ca. 810 Ma Madiyi Formation, lower Banxi Group in the central South China Block (SCB). Detailed thermal demagnetization reveals two distinct magnetic components among the samples. A low temperature component (LTC), removed from almost all the samples below 580°C, yielded a paleopole at 68.0°N, 211.7°E (A95=1.9) that is close to the pole of late Jurassic. The high temperature component (HTC), isolated between 580-690°C, gave a mean direction of D=310.0°, I=57.4°, α95=3.7 (108 samples of 13 sites) after bedding correction, corresponding to a paleomagnetic pole at 47.6°N, 46.7°E (A95=5.6°). The HTC passed a reversal test on 95% and 99% confidence level. Directional distribution of the HTC show significant elongation which may indicate inclination shallowing, and the inclination was corrected to 75.1° using E/I technique, corresponding to a paleolatitude at 60.8±3.4° of research area. The paleopole calculated from the E/I-corrected HTC is at 44.8°N, 80.2°E (A95=3.4°), being significantly distinct from any younger poles of the SCB. This new pole plus existing high quality paleomagnetic poles from the SCB demonstrate that the SCB experienced a polar-equatorial region drifting tendency from 825 Ma to Cambrian. The high-paleolatitude red beds rather than glacial sediments deposited in the SCB, combined with coeval widespread evaporative in other continents, possibly suggest pre-Cryogenian global greenhouse climate. In our reconstruction at 800 Ma, the SCB was placed on the northwest periphery of Rodinia, with its western margin adjacent to the northern India, rather than occupying a central position of Rodinia. The distribution of 825-750 Ma poles of the SCB, East Svalbard, Australia, Laurentia, India along a great arc may be associated with true polar wander around 800 Ma.

A versatile breast reduction technique: Conical plicated central U shaped (COPCUs) mammaplasty

PubMed Central

Copcu, Eray

2009-01-01

Background There have been numerous studies on reduction mammaplasty and its modifications in the literature. The multitude of modifications of reduction mammaplasty indicates that the ideal technique has yet to be found. There are four reasons for seeking the ideal technique. One reason is to preserve functional features of the breast: breastfeeding and arousal. Other reasons are to achieve the real geometric and aesthetic shape of the breast with the least scar and are to minimize complications of prior surgical techniques without causing an additional complication. Last reason is the limitation of the techniques described before. To these aims, we developed a new versatile reduction mammaplasty technique, which we called conical plicated central U shaped (COPCUs) mammaplasty. Methods We performed central plication to achieve a juvenile look in the superior pole of the breast and to prevent postoperative pseudoptosis and used central U shaped flap to achieve maximum NAC safety and to preserve lactation and nipple sensation. The central U flap was 6 cm in width and the superior conical plication was performed with 2/0 PDS. Preoperative and postoperative standard measures of the breast including the superior pole fullness were compared. Results Forty six patients were operated with the above mentioned technique. All of the patients were satisfied with functional and aesthetic results and none of them had major complications. There were no changes in the nipple innervation. Six patients becoming pregnant after surgery did not experience any problems with lactation. None of the patients required scar revision. Conclusion Our technique is a versatile, safe, reliable technique which creates the least scar, avoids previously described disadvantages, provides maximum preservation of functions, can be employed in all breasts regardless of their sizes. PMID:19575809

Low loss pole configuration for multi-pole homopolar magnetic bearings

NASA Technical Reports Server (NTRS)

Blumenstock, Kenneth A. (Inventor); Hakun, Claef F. (Inventor)

2001-01-01

A new pole configuration for multi-pole homopolar bearings proposed in this invention reduces rotational losses caused by eddy-currents generated when non-uniform flux distributions exist along the rotor surfaces. The new homopolar magnetic bearing includes a stator with reduced pole-to-pole and exhibits a much more uniform rotor flux than with large pole-to-pole gaps. A pole feature called a pole-link is incorporated into the low-loss poles to provide a uniform pole-to-pole gap and a controlled path for pole-to-pole flux. In order to implement the low-loss pole configuration of magnetic bearings with small pole-to-pole gaps, a new stator configuration was developed to facilitate installation of coil windings. The stator was divided into sector shaped pieces, as many pieces as there are poles. Each sector-shaped pole-piece can be wound on a standard coil winding machine, and it is practical to wind precision layer wound coils. To achieve maximum actuation efficiency, it is desirable to use all the available space for the coil formed by the natural geometric configuration. Then, the coils can be wound in a tapered shape. After winding, the sectored-pole-pieces are installed into and fastened by bonding or other means, to a ring of material which encloses the sectored-pole-pieces, forming a complete stator.

A survey of the use of ultrasound guidance in internal jugular venous cannulation.

PubMed

McGrattan, T; Duffty, J; Green, J S; O'Donnell, N

2008-11-01

It has been that suggested the use of two dimensional (2D) ultrasound to facilitate placement of central venous cannulae in the internal jugular vein improves patient safety and reduces complications. Since the introduction of the National Institute for Clinical Excellence Technology Appraisal Guideline Number 49 in 2002, promoting the use of ultrasound in placement of internal jugular venous cannulae, utilisation of ultrasound has increased throughout the United Kingdom. We report the findings of a postal survey of 2000 senior anaesthetists in the United Kingdom which enquired about their use of ultrasound for internal jugular vein cannulae placement. Only 27% use 2D ultrasound as their first choice technique, although 35% use it as their first choice when teaching. There was no significant difference in practice between those working within a sub specialty in anaesthesia. There continues to be discrepancies between the application of the guideline and how senior anaesthetists both site and teach the placement of internal jugular vein central venous cannulae.

Inferior Alveolar Nerve Lateralization and Transposition for Dental Implant Placement. Part I: a Systematic Review of Surgical Techniques

PubMed Central

Juodzbalys, Gintaras

2015-01-01

ABSTRACT Objectives The purpose of this first part of a two-part series was to review the literature concerning the indications, contraindications, advantages, disadvantages and surgical techniques of the lateralization and transposition of the inferior alveolar nerve, followed by the placement of an implant in an edentulous atrophic posterior mandible. Material and Methods A comprehensive review of the current literature was conducted according to the PRISMA guidelines by accessing the NCBI PubMed and PMC database, academic sites and books. The articles were searched from January 1997 to July 2014 and comprised English-language articles that included adult patients between 18 and 80 years old with minimal residual bone above the mandibular canal who had undergone inferior alveolar nerve (IAN) repositioning with a minimum 6 months of follow-up. Results A total of 16 studies were included in this review. Nine were related to IAN transposition, 4 to IAN lateralization and 3 to both transposition and lateralization. Implant treatment results and complications were presented. Conclusions Inferior alveolar nerve lateralization and transposition in combination with the installation of dental implants is sometimes the only possible procedure to help patients to obtain a fixed prosthesis, in edentulous atrophic posterior mandibles. With careful pre-operative surgical and prosthetic planning, imaging, and extremely precise surgical technique, this procedure can be successfully used for implant placement in edentulous posterior mandibular segments. PMID:25937873

[A comparative study between two procedures of TVT retropubic mid-urethral sling placement for treatment of female stress urinary incontinence].

PubMed

Sergent, F; Gay-Crosier, G; Resch, B; Pons, J-C; Marpeau, L

2014-03-01

To evaluate complications and functional outcomes at 1 year and more of a modified Tension-free Vaginal Tape (TVT) technique from that of classic TVT. Retrospective study comparing the two techniques. For the modified TVT technique, a peri-urethrovesical hydrodissection was performed. An 18-gauge hollow needle, in which a thread was introduced, was used as an ancillary for the placement of the sling. The sling was secured to the thread and then positioned with it. Bladder filling objectified perforations. An absorbable suture around the sling allowed its descent if necessary. One hundred and eighteen procedures were performed (54 classic TVT and 64 modified TVT). For the standard TVT and the modified TVT, the vesico-urethral perforation rates were respectively 7.4% and 1.5% (P<0.05), those of reoperations for pulling the sling downward 11.1% and 1.5% (P<0.05). A 1 year and more, healing and satisfaction rates were respectively 83.3% and 79.2% for the standard TVT versus 88.2% and 90% for the modified TVT (NS). The dissatisfaction rate was lower for the modified TVT (P<0.05). By modifying the placement of the classic TVT, it is possible to reduce its complications while maintaining its efficacy. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Radiologic Percutaneous Gastrostomy in Nondistended Stomach: A Modified Approach

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

Petrocelli, Francesco, E-mail: francesco.petrocelli@hsanmartino.it; Salsano, Giancarlo, E-mail: giancarlo.salsano@yahoo.it; Bovio, Giulio, E-mail: giulio.bovio@hsanmartino.it

IntroductionGastrostomy tube placement for patients requiring long-term nutritional support may be performed using different techniques including endoscopic, surgical, and percutaneous radiologically guided methods. Radiologically inserted gastrostomy (RIG), typically performed when percutaneous endoscopic gastrostomy is not possible, requires proper gastric distension that is achieved by insufflating air through a nasogastric tube. We describe a simple technique to prevent air escape from the stomach during gastrostomy tube placement. To the best of our knowledge, this technique has not yet been described in the literature.Materials and MethodsFour patients with unsuccessful percutaneous endoscopic gastrostomy were referred for fluoroscopic-guided gastrostomy. One patient had a pyriformmore » sinus tumor and three had an ischemic stroke causing dysphagia. Gastric distention was not achieved in the patients due to air escaping into the bowel during the standard RIG procedure. A modified approach using a balloon catheter inflated in the pylorus to avoid air passing into the duodenum permitted successful RIG.ResultsThe modified RIG procedure was successfully carried out in all cases without complications.DiscussionInadequate air distension of the stomach is an unusual event that causes a failure of gastrostomy tube placement and an increased risk of both major and minor complications. The use of a balloon catheter inflated in the first part of the duodenum prevents the air passage into the bowel allowing the correct positioning of the gastrostomy.« less

Real-Time Ultrasound-Guided Catheter Navigation for Approaching Deep-Seated Brain Lesions: Role of Intraoperative Neurosonography with and without Fusion with Magnetic Resonance Imaging.

PubMed

Manjila, Sunil; Karhade, Aditya; Phi, Ji Hoon; Scott, R Michael; Smith, Edward R

2017-01-01

Brain shift during the exposure of cranial lesions may reduce the accuracy of frameless stereotaxy. We describe a rapid, safe, and effective method to approach deep-seated brain lesions using real-time intraoperative ultrasound placement of a catheter to mark the dissection trajectory to the lesion. With Institutional Review Board approval, we retrospectively reviewed the radiographic, pathologic, and intraoperative data of 11 pediatric patients who underwent excision of 12 lesions by means of this technique. Full data sets were available for 12 lesions in 11 patients. Ten lesions were tumors and 2 were cavernous malformations. Lesion locations included the thalamus (n = 4), trigone (n = 3), mesial temporal lobe (n = 3), and deep white matter (n = 2). Catheter placement was successful in all patients, and the median time required for the procedure was 3 min (range 2-5 min). There were no complications related to catheter placement. The median diameter of surgical corridors on postresection magnetic resonance imaging was 6.6 mm (range 3.0-12.1 mm). Use of real-time ultrasound guidance to place a catheter to aid in the dissection to reach a deep-seated brain lesion provides advantages complementary to existing techniques, such as frameless stereotaxy. The catheter insertion technique described here provides a quick, accurate, and safe method for reaching deep-seated lesions. © 2017 S. Karger AG, Basel.

Unicompartmental knee arthroplasty: is robotic technology more accurate than conventional technique?

PubMed

Citak, Mustafa; Suero, Eduardo M; Citak, Musa; Dunbar, Nicholas J; Branch, Sharon H; Conditt, Michael A; Banks, Scott A; Pearle, Andrew D

2013-08-01

Robotic-assisted unicompartmental knee arthroplasty (UKA) with rigid bone fixation "can significantly improve implant placement and leg alignment. The aim of this cadaveric study was to determine whether the use of robotic systems with dynamic bone tracking would provide more accurate UKA implant positioning compared to the conventional manual technique. Three-dimensional CT-based preoperative plans were created to determine the desired position and orientation for the tibial and femoral components. For each pair of cadaver knees, UKA was performed using traditional instrumentation on the left side and using a haptic robotic system on the right side. Postoperative CT scans were obtained and 3D-to-3D iterative closest point registration was performed. Implant position and orientation were compared to the preoperative plan. Surgical RMS errors for femoral component placement were within 1.9 mm and 3.7° in all directions of the planned implant position for the robotic group, while RMS errors for the manual group were within 5.4mm and 10.2°. Average RMS errors for tibial component placement were within 1.4mm and 5.0° in all directions for the robotic group; while, for the manual group, RMS errors were within 5.7 mm and 19.2°. UKA was more precise using a semiactive robotic system with dynamic bone tracking technology compared to the manual technique. Copyright © 2012 Elsevier B.V. All rights reserved.

A technique to prevent capturing birds in unattended, furled mist nets

USGS Publications Warehouse

Sykes, P.W.

1989-01-01

A technique was developed to prevent the inadvertent capturing of birds in unattended mist nets left in place for long periods of time. This was accomplished by placing furled nets on top of 9-inch wide strips of 30-pound roofing felt secured to the ground between net support poles. All materials used are widely available and procedures used to make the felt strips and install them are described.

Atherectomy in complex infrainguinal lesions: a review.

PubMed

Engelberger, S; van den Berg, J C

2015-02-01

In the femoropopliteal segment, endovascular revascularization techniques have gained the role as a first line treatment strategy. Nitinol stent placement has improved the short- and mid-term primary patency rates in most lesion types and is therefore widely applied. Stenting has several shortcomings as in-stent restenosis, stent fractures and foreign material being left behind in the vessel. The concept of atherectomy is plaque debulking. This results in a potential reduction of inflation pressure requirements in angioplasty. Stent placement and consecutive in-stent restenosis may be avoided. In this non systematic literature review, the performance of different atherectomy techniques, such as direct atherectomy, orbital atherectomy, laser debulking and rotational atherectomy in the treatment of complex femoropopliteal lesions, including long lesions, moderately to heavily calcified lesions as well as occlusions and in-stent restenosis, has been analyzed.

A simple method to ensure proper screw position and plate size selection using the Morscher cervical spine locking plate. Technical note.

PubMed

Ball, P A; Benzel, E C; Baldwin, N G

1994-04-01

The use of bone plate instrumentation with screw fixation has proved to be a useful adjunctive measure in anterior cervical spine fusion surgery. Proper fitting, positioning, and attachment of this instrumentation have been shown to be frequently suboptimal if done without radiographic guidance. The most commonly used method of radiographic assistance for placement of this instrumentation is fluoroscopy. While this gives satisfactory technical results, it is expensive and time-consuming, and exposes the patient and the operating room personnel to ionizing radiation. The authors present a simple technique to ensure screw placement and plate fitting using Kirschner wires and a single lateral radiograph. This technique saves time, reduces exposure to radiation, and has led to satisfactory results in over 20 operative cases.

Endoscopic bilateral stent-in-stent placement for malignant hilar obstruction using a large cell type stent.

PubMed

Park, Jin Myung; Lee, Sang Hyub; Chung, Kwang Hyun; Jang, Dong Kee; Ryu, Ji Kon; Kim, Yong-Tae; Lee, Jae Min; Paik, Woo Hyun

2016-12-01

Bilateral stent-in-stent (SIS) self-expandable metal stent placement is technically challenging for palliation of unresectable malignant hilar obstruction. In the SIS technique, the uniform large cell type biliary stent facilitates contralateral stent deployment through the mesh of the first metallic stent. This study aimed to assess the technical success and clinical effectiveness of this technique with a uniform large cell type biliary stent. Thirty-one patients who underwent bilateral SIS placement using a large cell type stent were reviewed retrospectively. All patients showed malignant hilar obstruction (Bismuth types II, III, IV) with different etiologies. Sixteen (51.6%) patients were male. The mean age of the patients was 67.0+/-14.0 years. Most patients were diagnosed as having hilar cholangiocarcinoma (58.1%) and gallbladder cancer (29.0%). Technical success rate was 83.9%. Success was achieved more frequently in patients without masses obstructing the biliary confluence (MOC) than those with MOC (95.2% vs 60.0%, P=0.03). Functional success rate was 77.4%. Complications occurred in 29.0% of the patients. These tended to occur more frequently in patients with MOC (50.0% vs 19.0%, P=0.11). Median time to recurrent biliary obstruction was 188 days and median survival was 175 days. The large cell type stent can be used efficiently for bilateral SIS placement in malignant hilar obstruction. However, the risk of technical failure increases in patients with MOC, and caution is needed to prevent complications for these patients.

Cortical geometry may influence placement of interface between Par protein domains in early Caenorhabditis elegans embryos.

PubMed

Dawes, Adriana T; Iron, David

2013-09-21

During polarization, proteins and other polarity determinants segregate to the opposite ends of the cell (the poles) creating biochemically and dynamically distinct regions. Embryos of the nematode worm Caenorhabditis elegans (C. elegans) polarize shortly after fertilization, creating distinct regions of Par protein family members. These regions are maintained through to first cleavage when the embryo divides along the plane specified by the interface between regions, creating daughter cells with different protein content. In wild type single cell embryos the interface between these Par protein regions is reliably positioned at approximately 60% egg length, however, it is not known what mechanisms are responsible for specifying the position of the interface. In this investigation, we use two mathematical models to investigate the movement and positioning of the interface: a biologically based reaction-diffusion model of Par protein dynamics, and the analytically tractable perturbed Allen-Cahn equation. When we numerically simulate the models on a static 2D domain with constant thickness, both models exhibit a persistently moving interface that specifies the boundary between distinct regions. When we modify the simulation domain geometry, movement halts and the interface is stably positioned where the domain thickness increases. Using asymptotic analysis with the perturbed Allen-Cahn equation, we show that interface movement depends explicitly on domain geometry. Using a combination of analytic and numeric techniques, we demonstrate that domain geometry, a historically overlooked aspect of cellular simulations, may play a significant role in spatial protein patterning during polarization. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tissue Reinforcement in Implant-based Breast Reconstruction

PubMed Central

Scheflan, Michael

2014-01-01

Background: Tissue reinforcement with allogeneic or xenogeneic acellular dermal matrices (ADMs) is increasingly used in single-stage (direct-to-implant) and 2-stage implant-based breast reconstruction following mastectomy. ADMs allow surgeons to control implant position and obviate the need for submuscular implant placement. Here, we review the benefits and risks of using ADMs in implant-based breast reconstruction based on available data. Methods: A comprehensive analysis of the literature with focus on recent publications was performed. Additional information regarding the proper use of ADMs was based on our institutional experience. Results: ADM use may improve definition of the lateral confines of the breast and lower pole projection. It may facilitate direct-to-implant procedures and improve aesthetic outcomes. The effect of ADMs on complication rates remains controversial. Known patient risk factors such as obesity, smoking, and radiotherapy should be considered during patient selection. For patients with healthy, well-vascularized skin envelopes, ADM-assisted direct-to- implant reconstruction is a safe and cost-effective alternative to 2-stage implant reconstruction, with low complication rates. ADMs may be used to treat capsular contracture, and limited available data further suggest the possibility that ADMs may reduce the risk of capsular contracture. Novel synthetic or biosynthetic tissue reinforcement devices with different physical and ease-of-use properties than ADMs are emerging options for reconstructive surgeons and patients who seek to avoid tissue products from human or mammalian cadavers. Conclusions: ADM-assisted implant-based breast reconstruction may improve aesthetic outcomes. However, appropriate patient selection, surgical technique, and postoperative management are critical for its success, including minimizing the risk of complications. PMID:25426375

Techniques for Type I Collagen Organization

NASA Astrophysics Data System (ADS)

Anderson-Jackson, LaTecia Diamond

Tissue Engineering is a process in which cells, engineering, and material methods are used in amalgamation to improve biological functions. The purpose of tissue engineering is to develop alternative solutions to treat or cure tissues and organs that have been severely altered or damaged by diseases, congenital defects, trauma, or cancer. One of the most common and most promising biological materials for tissue engineering to develop scaffolds is Type I collagen. A major challenge in biomedical research is aligning Type I collagen to mimic biological structures, such as ligaments, tendons, bones, and other hierarchal aligned structures within the human body. The intent of this research is to examine possible techniques for organizing Type I collagen and to assess which of the techniques is effective for potential biological applications. The techniques used in this research to organize collagen are soft lithography with solution-assisted sonication embossing, directional freezing, and direct poling. The final concentration used for both soft lithography with solution-assisted sonication embossing and direct poling was 1 mg/ml, whereas for directional freezing the final concentration varied between 4mg/ml, 2mg/ml, and 1 mg/ml. These techniques were characterized using the Atomic Force Microscope (AFM) and Helium Ion Microscope (HIM). In this study, we have found that out of the three techniques, the soft lithography and directional freezing techniques have been successful in organizing collagen in a particular pattern, but not alignment. We concluded alignment may be dependent on the pH of collagen and the amount of acetic acid used in collagen solution. However, experiments are still being conducted to optimize all three techniques to align collagen in a unidirectional arrangement.

National Alliance of Business Sales Techniques and Results (STAR).

ERIC Educational Resources Information Center

Golightly, Steven J.

This paper presents an overview of the Sales Techniques and Results (STAR) training program developed by the National Alliance of Business in conjunction with IBM. The STAR training program can be used to help vocational directors, teachers, and counselors to be better salespersons for cooperative education or job placement programs. The paper…

RJMCMC based Text Placement to Optimize Label Placement and Quantity

NASA Astrophysics Data System (ADS)

Touya, Guillaume; Chassin, Thibaud

2018-05-01

Label placement is a tedious task in map design, and its automation has long been a goal for researchers in cartography, but also in computational geometry. Methods that search for an optimal or nearly optimal solution that satisfies a set of constraints, such as label overlapping, have been proposed in the literature. Most of these methods mainly focus on finding the optimal position for a given set of labels, but rarely allow the removal of labels as part of the optimization. This paper proposes to apply an optimization technique called Reversible-Jump Markov Chain Monte Carlo that enables to easily model the removal or addition during the optimization iterations. The method, quite preliminary for now, is tested on a real dataset, and the first results are encouraging.

Guided Immediate Implant Placement with Wound Closure by Computer-Aided Design/Computer-Assisted Manufacture Sealing Socket Abutment: Case Report.

PubMed

Finelle, Gary; Lee, Sang J

Digital technology has been widely used in the field of implant dentistry. From a surgical standpoint, computer-guided surgery can be utilized to enhance primary implant stability and to improve the precision of implant placement. From a prosthetic standpoint, computer-aided design/computer-assisted manufacture (CAD/CAM) technology has brought about various restorative options, including the fabrication of customized abutments through a virtual design based on computer-guided surgical planning. This case report describes a novel technique combining the use of a three-dimensional (3D) printed surgical template for the immediate placement of an implant, with CAD/CAM technology to optimize hard and soft tissue healing after bone grafting with the use of a socket sealing abutment.

Experience of Self-Harm and Its Treatment in Looked-After Young People: An Interpretative Phenomenological Analysis.

PubMed

Wadman, R; Armstrong, M; Clarke, D; Harroe, C; Majumder, P; Sayal, K; Vostanis, P; Townsend, E

2018-01-01

We report the first Interpretative Phenomenological Analysis examination of self-harm and experience of clinical services in young people in the public care system. Qualitative interviews with 24 looked-after young people were completed. Prevalent themes were 1) Changes in care placement, 2) Feelings of anger, 3) Not wanting/feeling able to talk, 4) Developing coping techniques, 5) Clinical services: A relational mixed bag (subthemes: feeling (i) patronized, not listened to, (ii) nothing being done, (iii) comfortable/able to talk). Placement change and anger were highly salient to self-harm in this group and experiences of clinical services depended on individual relationships with clinicians. Implications include increasing compassion in therapeutic relationships, recognizing and managing emotional dysregulation, and increasing support during placement changes.

Acute Iliac Artery Rupture: Endovascular Treatment

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

Chatziioannou, A.; Mourikis, D.; Katsimilis, J.

The authors present 7 patients who suffered iliac artery rupture over a 2 year period. In 5 patients, the rupture was iatrogenic: 4 cases were secondary to balloon angioplasty for iliac artery stenosis and 1 occurred during coronary angioplasty. In the last 2 patients, the rupture was secondary to iliac artery mycotic aneurysm. Direct placement of a stent-graft was performed in all cases, which was dilated until extravasation was controlled. Placement of the stent-graft was successful in all the cases, without any complications. The techniques used, results, and mid-term follow-up are presented. In conclusion, endovascular placement of a stent-graft ismore » a quick, minimally invasive, efficient, and safe method for emergency treatment of acute iliac artery rupture, with satisfactory short- and mid-term results.« less

PopZ identifies the new pole, and PodJ identifies the old pole during polar growth in Agrobacterium tumefaciens

PubMed Central

Grangeon, Romain; Zupan, John R.; Anderson-Furgeson, James; Zambryski, Patricia C.

2015-01-01

Agrobacterium tumefaciens elongates by addition of peptidoglycan (PG) only at the pole created by cell division, the growth pole, whereas the opposite pole, the old pole, is inactive for PG synthesis. How Agrobacterium assigns and maintains pole asymmetry is not understood. Here, we investigated whether polar growth is correlated with novel pole-specific localization of proteins implicated in a variety of growth and cell division pathways. The cell cycle of A. tumefaciens was monitored by time-lapse and superresolution microscopy to image the localization of A. tumefaciens homologs of proteins involved in cell division, PG synthesis and pole identity. FtsZ and FtsA accumulate at the growth pole during elongation, and improved imaging reveals FtsZ disappears from the growth pole and accumulates at the midcell before FtsA. The L,D-transpeptidase Atu0845 was detected mainly at the growth pole. A. tumefaciens specific pole-organizing protein (Pop) PopZAt and polar organelle development (Pod) protein PodJAt exhibited dynamic yet distinct behavior. PopZAt was found exclusively at the growing pole and quickly switches to the new growth poles of both siblings immediately after septation. PodJAt is initially at the old pole but then also accumulates at the growth pole as the cell cycle progresses suggesting that PodJAt may mediate the transition of the growth pole to an old pole. Thus, PopZAt is a marker for growth pole identity, whereas PodJAt identifies the old pole. PMID:26324921

Exercise economy in skiing and running

PubMed Central

Losnegard, Thomas; Schäfer, Daniela; Hallén, Jostein

2014-01-01

Substantial inter-individual variations in exercise economy exist even in highly trained endurance athletes. The variation is believed to be determined partly by intrinsic factors. Therefore, in the present study, we compared exercise economy in V2-skating, double poling, and uphill running. Ten highly trained male cross-country skiers (23 ± 3 years, 180 ± 6 cm, 75 ± 8 kg, VO2peak running: 76.3 ± 5.6 mL·kg−1·min−1) participated in the study. Exercise economy and VO2peak during treadmill running, ski skating (V2 technique) and double poling were compared based on correlation analysis. There was a very large correlation in exercise economy between V2-skating and double poling (r = 0.81) and large correlations between V2-skating and running (r = 0.53) and double poling and running (r = 0.58). There were trivial to moderate correlations between exercise economy and the intrinsic factors VO2peak (r = 0.00–0.23), cycle rate (r = 0.03–0.46), body mass (r = −0.09–0.46) and body height (r = 0.11–0.36). In conclusion, the inter-individual variation in exercise economy could be explained only moderately by differences in VO2peak, body mass and body height. Apparently other intrinsic factors contribute to the variation in exercise economy between highly trained subjects. PMID:24478718

The Dermal Apron Technique for Immediate Implant Socket Management: A Novel Technique.

PubMed

Levin, Barry P

2016-01-01

With immediate implant placement and provisionalization (IIP) in the esthetic zone, measures to counter hard and soft tissue loss are frequently necessary. To reduce the morbidity associated with bone and connective tissue procurement, various exogenous materials are utilized. The "Dermal Apron Technique" presented in this article demonstrates the use of a composite bone particulate (allograft/xenograft) plus a dermal allograft, adapted around screw-retained temporary crowns and secured within a subperiosteal pouch. The purpose is to augment the thickness of peri-implant mucosa for the purpose of preserving ridge dimensions and preventing mucosal recession. Controlled studies are required to further support its use. Clinical significance: Soft tissue health and harmony are critical for successful implant therapy in the esthetic regions of the dentition. Often, autogenous soft tissue grafts are used to augment peri-implant soft tissues. The Dermal Apron Technique is a method, that in specific situations, obviates the need for autogenous grafting. This reduces treatment time and morbidity associated with procurement of these grafts. The Dermal Apron Technique is used simultaneous with immediate placement and provisionalization and can improve long-term esthetic outcomes for patients. © 2016 Wiley Periodicals, Inc.

[Mastopexy in Massive Weight Loss Patients - Extended Ribeiro Technique and Usage of the Lateral Intercostal Artery Perforator Flap (LICAP Flap) for Autoaugmentation].

PubMed

Wolter, Andreas; Scholz, Till; Pluto, Naja; Diedrichson, Jens; Arens-Landwehr, Andreas; Liebau, Jutta

2017-12-01

 Mastopexy in massive weight loss patients is challenging. The breast mound is often unstable and deflated, with a loose inelastic skin envelope. It has become apparent that mammaplasty techniques in these cases should rely more on glandular recontouring rather than on the skin envelope for shaping. Published methods include plication, suspension and autoaugmentation. The residual local tissue (glandular breast tissue, fat tissue, dermoglandular fat flap) is utilised to its full extent in order to reshape a form-stable breast with full upper pole projection. The evolution of a technique is presented.  In this study we retrospectively analysed 68 massive weight loss patients who underwent an extended Ribeiro technique with a superomedial pedicle mastopexy and suspension by an inferior dermoglandular flap. The current procedure involves incorporating the lateral intercostal artery perforator flap (LICAP flap) and medial breast pillar additionally to the inferior dermoglandular Ribeiro flap. This essentially autoaugments the upper pole by creating an "autoprosthesis", narrows the widened breast, and redefines the inframammary fold. The outcome parameters complication rate, patient satisfaction with the aesthetic result, nipple sensibility and surgical revision rate were obtained.  From 01/2011 to 12/2016, we performed 136 autoaugmentation mastopexies. The average age was 41.2 years, average body mass index (BMI) was 27,1 kg/m 2 , average weight loss was 54.3 kg, average sternal notch-NAC distance was 32.3 cm, average operation time was 109 minutes. In 12 breasts, a free-nipple graft was necessary. The complication rate was 5.1 %, surgical revision rate was 17.6 %. 95 % of the patients were "very satisfied" or "satisfied" with the aesthetic result. Nipple sensibility was rated as "very good" or "good" by 85 % of patients.  Modification of the Ribeiro technique by using the medial and lateral breast pillar (LICAP flap) allows autoaugmentation of the upper pole. Parenchymal shaping through plication and suspension of the breast mound should improve breast shape over time, with the aim of reducing the incidence of recurrent ptosis. The presented technique is a reproducible and reliable method with a low complication rate. Georg Thieme Verlag KG Stuttgart · New York.

Efficient full-chip SRAF placement using machine learning for best accuracy and improved consistency

NASA Astrophysics Data System (ADS)

Wang, Shibing; Baron, Stanislas; Kachwala, Nishrin; Kallingal, Chidam; Sun, Dezheng; Shu, Vincent; Fong, Weichun; Li, Zero; Elsaid, Ahmad; Gao, Jin-Wei; Su, Jing; Ser, Jung-Hoon; Zhang, Quan; Chen, Been-Der; Howell, Rafael; Hsu, Stephen; Luo, Larry; Zou, Yi; Zhang, Gary; Lu, Yen-Wen; Cao, Yu

2018-03-01

Various computational approaches from rule-based to model-based methods exist to place Sub-Resolution Assist Features (SRAF) in order to increase process window for lithography. Each method has its advantages and drawbacks, and typically requires the user to make a trade-off between time of development, accuracy, consistency and cycle time. Rule-based methods, used since the 90 nm node, require long development time and struggle to achieve good process window performance for complex patterns. Heuristically driven, their development is often iterative and involves significant engineering time from multiple disciplines (Litho, OPC and DTCO). Model-based approaches have been widely adopted since the 20 nm node. While the development of model-driven placement methods is relatively straightforward, they often become computationally expensive when high accuracy is required. Furthermore these methods tend to yield less consistent SRAFs due to the nature of the approach: they rely on a model which is sensitive to the pattern placement on the native simulation grid, and can be impacted by such related grid dependency effects. Those undesirable effects tend to become stronger when more iterations or complexity are needed in the algorithm to achieve required accuracy. ASML Brion has developed a new SRAF placement technique on the Tachyon platform that is assisted by machine learning and significantly improves the accuracy of full chip SRAF placement while keeping consistency and runtime under control. A Deep Convolutional Neural Network (DCNN) is trained using the target wafer layout and corresponding Continuous Transmission Mask (CTM) images. These CTM images have been fully optimized using the Tachyon inverse mask optimization engine. The neural network generated SRAF guidance map is then used to place SRAF on full-chip. This is different from our existing full-chip MB-SRAF approach which utilizes a SRAF guidance map (SGM) of mask sensitivity to improve the contrast of optical image at the target pattern edges. In this paper, we demonstrate that machine learning assisted SRAF placement can achieve a superior process window compared to the SGM model-based SRAF method, while keeping the full-chip runtime affordable, and maintain consistency of SRAF placement . We describe the current status of this machine learning assisted SRAF technique and demonstrate its application to full chip mask synthesis and discuss how it can extend the computational lithography roadmap.

Early experience of placing image-guided minimally invasive pedicle screws without K-wires or bone-anchored trackers.

PubMed

Malham, Gregory M; Parker, Rhiannon M

2018-04-01

OBJECTIVE Image guidance for spine surgery has been reported to improve the accuracy of pedicle screw placement and reduce revision rates and radiation exposure. Current navigation and robot-assisted techniques for percutaneous screws rely on bone-anchored trackers and Kirchner wires (K-wires). There is a paucity of published data regarding the placement of image-guided percutaneous screws without K-wires. A new skin-adhesive stereotactic patient tracker (SpineMask) eliminates both an invasive bone-anchored tracker and K-wires for pedicle screw placement. This study reports the authors' early experience with the use of SpineMask for "K-wireless" placement of minimally invasive pedicle screws and makes recommendations for its potential applications in lumbar fusion. METHODS Forty-five consecutive patients (involving 204 screws inserted) underwent K-wireless lumbar pedicle screw fixation with SpineMask and intraoperative neuromonitoring. Screws were inserted by percutaneous stab or Wiltse incisions. If required, decompression with or without interbody fusion was performed using mini-open midline incisions. Multimodality intraoperative neuromonitoring assessing motor and sensory responses with triggered electromyography (tEMG) was performed. Computed tomography scans were obtained 2 days postoperatively to assess screw placement and any cortical breaches. A breach was defined as any violation of a pedicle screw involving the cortical bone of the pedicle. RESULTS Fourteen screws (7%) required intraoperative revision. Screws were removed and repositioned due to a tEMG response < 13 mA, tactile feedback, and 3D fluoroscopic assessment. All screws were revised using the SpineMask with the same screw placement technique. The highest proportion of revisions occurred with Wiltse incisions (4/12, 33%) as this caused the greatest degree of SpineMask deformation, followed by a mini midline incision (3/26, 12%). Percutaneous screws via a single stab incision resulted in the fewest revisions (7/166, 4%). Postoperative CT demonstrated 7 pedicle screw breaches (3%; 5 lateral, 1 medial, 1 superior), all with percutaneous stab incisions (7/166, 4%). The radiological accuracy of the SpineMask tracker was 97% (197/204 screws). No patients suffered neural injury or required postoperative screw revision. CONCLUSIONS The noninvasive cutaneous SpineMask tracker with 3D image guidance and tEMG monitoring provided high accuracy (97%) for percutaneous pedicle screw placement via stab incisions without K-wires.

Interplanetary gas. XX - Does the radial solar wind speed increase with latitude

NASA Technical Reports Server (NTRS)

Brandt, J. C.; Harrington, R. S.; Roosen, R. G.

1975-01-01

The astrometric technique used to derive solar wind speeds from ionic comet-tail orientations has been used to test the suggestion that the radial solar wind speed is higher near the solar poles than near the equator. We find no evidence for the suggested latitude variation.

Rotor for a brushless micromotor

NASA Astrophysics Data System (ADS)

Gilles, P.-A.; Delamare, J.; Cugat, O.

2002-04-01

Synchronous planar micromotors are studied at LEG, with diameters ranging from φ 3 to φ 8 mm. They combine state-of-the-art collective means of fabrication with watch industry techniques. This paper describes the design, simulation, fabrication and magnetisation of disc-shaped SmCo rotors with several axial pairs of poles.

Search for PeVatrons at the Galactic Center using a radio air-shower array at the South Pole

NASA Astrophysics Data System (ADS)

Balagopal V., A.; Haungs, A.; Huege, T.; Schröder, F. G.

2018-02-01

The South Pole, which hosts the IceCube Neutrino Observatory, has a complete and around-the-clock exposure to the Galactic Center. Hence, it is an ideal location to search for gamma rays of PeV energy coming from the Galactic Center. However, it is hard to detect air showers initiated by these gamma rays using cosmic-ray particle detectors due to the low elevation of the Galactic Center. The use of antennas to measure the radio footprint of these air showers will help in this case, and would allow for a 24/7 operation time. So far, only air showers with energies well above 10^{16} eV have been detected with the radio technique. Thus, the energy threshold has to be lowered for the detection of gamma-ray showers of PeV energy. This can be achieved by optimizing the frequency band in order to obtain a higher level of signal-to-noise ratio. With such an approach, PeV gamma-ray showers with high inclination can be measured at the South Pole.

High submuscular placement of urologic prosthetic balloons and reservoirs via transscrotal approach.

PubMed

Morey, Allen F; Cefalu, Christopher A; Hudak, Steven J

2013-02-01

Traditional placement of inflatable penile prosthesis (IPP) reservoirs and/or artificial urinary sphincter (AUS) balloons into the space of Retzius may be challenging following major pelvic surgery. The aim of this study is to report our 1-year experience using a novel technique for high balloon/reservoir placement beneath the rectus abdominus muscle, thus completely obviating deep pelvic dissection during prosthetic urologic surgery. A retrospective review of all patients who underwent IPP and/or AUS placement between June 2011 and June 2012 was performed. All had AUS balloons and/or IPP reservoirs placed in a submuscular location by bluntly tunneling through the external inguinal ring into a potential space between the transversalis fascia and the rectus abdominus muscle using a long, angled, lung grasping clamp. Patient demographics, perioperative outcomes, and initial follow-up patient-reported outcomes were reviewed. During the study period, 120 submuscular balloons/reservoirs were inserted in 107 consecutive patients who underwent placement of an IPP (61 patients), AUS (33 patients), or both (13 patients). Among our 48 most recent patients, 41 (85%) reported they were totally unable to feel their balloon/reservoir, and all but two patients reported no bother from the submuscular balloon/reservoir placement. Of the 120 total submuscular balloons and reservoirs, surgical time and outcomes of the prosthetic procedures appeared similar to those placed using traditional methods; two reservoirs required revision surgery for repositioning. High submuscular placement of genitourinary prosthetic balloons and reservoirs via a transscrotal approach is both safely and effective, while avoiding deep retropubic dissection. © 2012 International Society for Sexual Medicine.

Semi-automatic 10/20 Identification Method for MRI-Free Probe Placement in Transcranial Brain Mapping Techniques.

PubMed

Xiao, Xiang; Zhu, Hao; Liu, Wei-Jie; Yu, Xiao-Ting; Duan, Lian; Li, Zheng; Zhu, Chao-Zhe

2017-01-01

The International 10/20 system is an important head-surface-based positioning system for transcranial brain mapping techniques, e.g., fNIRS and TMS. As guidance for probe placement, the 10/20 system permits both proper ROI coverage and spatial consistency among multiple subjects and experiments in a MRI-free context. However, the traditional manual approach to the identification of 10/20 landmarks faces problems in reliability and time cost. In this study, we propose a semi-automatic method to address these problems. First, a novel head surface reconstruction algorithm reconstructs head geometry from a set of points uniformly and sparsely sampled on the subject's head. Second, virtual 10/20 landmarks are determined on the reconstructed head surface in computational space. Finally, a visually-guided real-time navigation system guides the experimenter to each of the identified 10/20 landmarks on the physical head of the subject. Compared with the traditional manual approach, our proposed method provides a significant improvement both in reliability and time cost and thus could contribute to improving both the effectiveness and efficiency of 10/20-guided MRI-free probe placement.

Combined Scleral Flap with Donor Scleral Patch Graft for Anterior Tube Placement in Glaucoma Drainage Device Surgery.

PubMed

Yu, Jea H; Nguyen, Chuck; Gallemore, Esmeralda; Gallemore, Ron P

2016-01-01

Purpose . To report a new technique for anterior placement of tubes for glaucoma drainage devices to reduce the risk of tube erosions. Methods . Retrospective review of select cases of Ahmed Valve surgery combined with the novel method of a limbal-based scleral flap covered by a scleral patch graft to cover the tube at the entrance through the limbus. Intraoperative and postoperative illustrations are shown to highlight the method of tube placement. Results . In this retrospective case series, 3 patients are presented illustrating the technique. Two had neovascular glaucoma and one had primary open-angle glaucoma (POAG). On average, intraocular pressure was reduced from 39 ± 14 mmHg to 15 ± 2 mmHg and the number of glaucoma medications was reduced from 4 ± 1 to 0. Preoperative and most recent visual acuities were hand-motion (HM) and HM, 20/60 and 20/50, and 20/70 and 20/30, respectively. Conclusion . The combination of a limbal-based scleral flap with scleral patch graft to cover the tube with glaucoma drainage devices may be an effective means to reduce erosion and protect against endophthalmitis.

Therapeutic esophageal interventions for dysphagia and bleeding.

PubMed

Siersema, Peter D

2006-07-01

This article reviews the most notable results of esophageal interventions for dysphagia and bleeding published in 2005. Long-term rubber tube placement was shown to be an interesting treatment option for difficult esophageal strictures. Two studies demonstrated that only 50% of patients who had undergone pneumatic dilation for achalasia were dysphagia-free after long-term follow-up. It was shown that patients with dysphagia from esophageal cancer should be treated by intraluminal radiotherapy (brachytherapy), whereas stent placement was preferable in those with a poor prognosis. Temporary stent placement is an option in patients undergoing radiotherapy for inoperable esophageal cancer to increase the dysphagia-free period. Two studies were published on the successful use of silicone-covered plastic stents for sealing of leaks after surgery of the esophagus. The optimal treatment for bleeding varices was confirmed to be endoscopic band ligation. A meta-analysis demonstrated that adding sclerotherapy to band ligation for secondary prophylaxis of bleeding varices had no effect on clinical outcome. In 2005, new techniques for the treatment of complicated strictures were presented. In addition, expanding indications for stents were reported. Finally, endoscopic band ligation was confirmed to be the most optimal technique for the treatment of varices.

Upper limb joint kinetics of three sitting pivot wheelchair transfer techniques in individuals with spinal cord injury

PubMed Central

Kankipati, Padmaja; Boninger, Michael L.; Gagnon, Dany; Cooper, Rory A.; Koontz, Alicia M.

2015-01-01

Study design Repeated measures design. Objective This study compared the upper extremity (UE) joint kinetics between three transfer techniques. Setting Research laboratory. Methods Twenty individuals with spinal cord injury performed three transfer techniques from their wheelchair to a level tub bench. Two of the techniques involved a head–hips method with leading hand position close (HH-I) and far (HH-A) from the body, and the third technique with the trunk upright (TU) and hand far from body. Motion analysis equipment recorded upper body movements and force sensors recorded their hand and feet reaction forces during the transfers. Results Several significant differences were found between HH-A and HH-I and TU and HH-I transfers indicating that hand placement was a key factor influencing the UE joint kinetics. Peak resultant hand, elbow, and shoulder joint forces were significantly higher for the HH-A and TU techniques at the trailing arm (P < 0.036) and lower at the leading arm (P < 0.021), compared to the HH-I technique. Conclusion Always trailing with the same arm if using HH-A or TU could predispose that arm to overuse related pain and injuries. Technique training should focus on initial hand placement close to the body followed by the amount of trunk flexion needed to facilitate movement. PMID:25130053

On the Aharonov-Bohm Operators with Varying Poles: The Boundary Behavior of Eigenvalues

NASA Astrophysics Data System (ADS)

Noris, Benedetta; Nys, Manon; Terracini, Susanna

2015-11-01

We consider a magnetic Schrödinger operator with magnetic field concentrated at one point (the pole) of a domain and half integer circulation, and we focus on the behavior of Dirichlet eigenvalues as functions of the pole. Although the magnetic field vanishes almost everywhere, it is well known that it affects the operator at the spectral level (the Aharonov-Bohm effect, Phys Rev (2) 115:485-491, 1959). Moreover, the numerical computations performed in (Bonnaillie-Noël et al., Anal PDE 7(6):1365-1395, 2014; Noris and Terracini, Indiana Univ Math J 59(4):1361-1403, 2010) show a rather complex behavior of the eigenvalues as the pole varies in a planar domain. In this paper, in continuation of the analysis started in (Bonnaillie-Noël et al., Anal PDE 7(6):1365-1395, 2014; Noris and Terracini, Indiana Univ Math J 59(4):1361-1403, 2010), we analyze the relation between the variation of the eigenvalue and the nodal structure of the associated eigenfunctions. We deal with planar domains with Dirichlet boundary conditions and we focus on the case when the singular pole approaches the boundary of the domain: then, the operator loses its singular character and the k-th magnetic eigenvalue converges to that of the standard Laplacian. We can predict both the rate of convergence and whether the convergence happens from above or from below, in relation with the number of nodal lines of the k-th eigenfunction of the Laplacian. The proof relies on the variational characterization of eigenvalues, together with a detailed asymptotic analysis of the eigenfunctions, based on an Almgren-type frequency formula for magnetic eigenfunctions and on the blow-up technique.

What the ultimate polymeric electro-optic materials will be: guest-host, crosslinked, or side-chain?

NASA Astrophysics Data System (ADS)

Zhang, Cheng; Zhang, Hua; Oh, Min-Cheol; Dalton, Larry R.; Steier, William H.

2003-07-01

Material processing and device fabrication of many different electro-optic (EO) polymers developed at USC are reviewed. Detailed discussion is given to guest-host CLD/APCs, crosslinking perfluorocyclobutane (PFCB) polymer CX1, and thermally stable side-chain polymers CX2 and CX3. Excellent EO performance (1.4V at 1.31 μm, 2.1 V at 1.55 μm) was achieved in CLD/APC Mach-Zehnder modulators (2-cm, push-pull). CLD/APCs also possess low optical losses (1.2 dB/cm in slab waveguides and in thick core channel waveguides). However, the guest-host materials only have limited thermal stability (110-132 °C in short term, <60 °C in long term) and require special techniques in device fabrication. The crosslinking polymer CX1 was able to provide long-term stability at 85 oC when fully cured. It also has a low optical loss (comparable to CLD/APCs) before curing and decent EO coefficient when poled at 180 °C. However, after the films were poled at the crosslinking temperatures (200 °C or above), the transmissions of the waveguides and EO activity became very poor due to poling-induced chromophore degradation. By judicial molecular design of both chromophore and monomer structures to suppress thermal motion of polymer segments, we were able to realize the same or even better thermal stability in side-chain polymers CX2 and CX3. Since no curing is needed, devices can be poled at their optimal poling temperatures, and all good properties can be obtained simultaneously. Despite the excellent solubility in chlorinated solvents, these side-chain polymers are resistant to some other organic solvents or solutions such as acetone, photoresist and various UV-curable liquids.

Automated Prescription of Oblique Brain 3D MRSI

PubMed Central

Ozhinsky, Eugene; Vigneron, Daniel B.; Chang, Susan M.; Nelson, Sarah J.

2012-01-01

Two major difficulties encountered in implementing Magnetic Resonance Spectroscopic Imaging (MRSI) in a clinical setting are limited coverage and difficulty in prescription. The goal of this project was to completely automate the process of 3D PRESS MRSI prescription, including placement of the selection box, saturation bands and shim volume, while maximizing the coverage of the brain. The automated prescription technique included acquisition of an anatomical MRI image, optimization of the oblique selection box parameters, optimization of the placement of OVS saturation bands, and loading of the calculated parameters into a customized 3D MRSI pulse sequence. To validate the technique and compare its performance with existing protocols, 3D MRSI data were acquired from 6 exams from 3 healthy volunteers. To assess the performance of the automated 3D MRSI prescription for patients with brain tumors, the data were collected from 16 exams from 8 subjects with gliomas. This technique demonstrated robust coverage of the tumor, high consistency of prescription and very good data quality within the T2 lesion. PMID:22692829

Continuous welding of unidirectional fiber reinforced thermoplastic tape material

NASA Astrophysics Data System (ADS)

Schledjewski, Ralf

2017-10-01

Continuous welding techniques like thermoplastic tape placement with in situ consolidation offer several advantages over traditional manufacturing processes like autoclave consolidation, thermoforming, etc. However, still there is a need to solve several important processing issues before it becomes a viable economic process. Intensive process analysis and optimization has been carried out in the past through experimental investigation, model definition and simulation development. Today process simulation is capable to predict resulting consolidation quality. Effects of material imperfections or process parameter variations are well known. But using this knowledge to control the process based on online process monitoring and according adaption of the process parameters is still challenging. Solving inverse problems and using methods for automated code generation allowing fast implementation of algorithms on targets are required. The paper explains the placement technique in general. Process-material-property-relationships and typical material imperfections are described. Furthermore, online monitoring techniques and how to use them for a model based process control system are presented.

Reconstruction of Long Bone Infections Using the Induced Membrane Technique: Tips and Tricks.

PubMed

Mauffrey, Cyril; Hake, Mark E; Chadayammuri, Vivek; Masquelet, Alain-Charles

2016-06-01

The management of posttraumatic long bone osteomyelitis remains a challenging clinical problem. A systematic approach is necessary, beginning with eradication of the infected bone and soft tissue. There are a number of options for reconstruction of the remaining bone defect, including the induced membrane technique developed by Masquelet. We describe our technique for the 2-stage treatment of long bone osteomyelitis. The first stage involves a radical debridement, stabilization of the bone with either external fixation or an antibiotic-coated intramedullary nail, and placement of a polymethylmethacrylate spacer. The second stage includes excision of the spacer and placement of autologous bone graft. Various resection methods, fixation strategies, antibiotic additives, and types of bone grafts or substitutes can be used. The purpose of our technical article is to share our personal experience and describe several nuances that are critical for the success of this treatment strategy. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

[The global impression technic in fixed dentures].

PubMed

Lamy, M; Mainjot, A

2001-01-01

The global impression technique allows to obtain in a single stage the impression of the abutment as well as their neighboring teeth. This technique often requires the placement of one or two retraction cords in the sulcus. The impression technique herein described is the double mix method. This method is based on the use of two elastomers with different viscosities, but from the same group thus allowing a simultaneous polymerization.

Electromagnetic Real Time Navigation in the Region of the Posterior Pelvic Ring: An Experimental In-Vitro Feasibility Study and Comparison of Image Guided Techniques.

PubMed

Pishnamaz, Miguel; Wilkmann, Christoph; Na, Hong-Sik; Pfeffer, Jochen; Hänisch, Christoph; Janssen, Max; Bruners, Philipp; Kobbe, Philipp; Hildebrand, Frank; Schmitz-Rode, Thomas; Pape, Hans-Christoph

2016-01-01

Electromagnetic tracking is a relatively new technique that allows real time navigation in the absence of radiation. The aim of this study was to prove the feasibility of this technique for the treatment of posterior pelvic ring fractures and to compare the results with established image guided procedures. Tests were performed in pelvic specimens (Sawbones®) with standardized sacral fractures (Type Denis I or II). A gel matrix simulated the operative approach and a cover was used to disable visual control. The electromagnetic setup was performed by using a custom made carbon reference plate and a prototype stainless steel K-wire with an integrated sensor coil. Four different test series were performed: Group OCT: Optical navigation using preoperative CT-scans; group O3D: Optical navigation using intraoperative 3-D-fluoroscopy; group Fluoro: Conventional 2-D-fluoroscopy; group EMT: Electromagnetic navigation combined with a preoperative Dyna-CT. Accuracy of screw placement was analyzed by standardized postoperative CT-scan for each specimen. Operation time and intraoperative radiation exposure for the surgeon was documented. All data was analyzed using SPSS (Version 20, 76 Chicago, IL, USA). Statistical significance was defined as p< 0.05. 160 iliosacral screws were placed (40 per group). EMT resulted in a significantly higher incidence of optimal screw placement (EMT: 36/40) compared to the groups Fluoro (30/40; p< 0.05) and OCT (31/40; p< 0.05). Results between EMT and O3D were comparable (O3D: 37/40; n.s.). Also, the operation time was comparable between groups EMT and O3D (EMT 7.62 min vs. O3D 7.98 min; n.s.), while the surgical time was significantly shorter compared to the Fluoro group (10.69 min; p< 0.001) and the OCT group (13.3 min; p< 0.001). Electromagnetic guided iliosacral screw placement is a feasible procedure. In our experimental setup, this method was associated with improved accuracy of screw placement and shorter operation time when compared with the conventional fluoroscopy guided technique and compared to the optical navigation using preoperative CT-scans. Further studies are necessary to rule out drawbacks of this technique regarding ferromagnetic objects.

Minimally Invasive Ponto Surgery compared to the linear incision technique without soft tissue reduction for bone conduction hearing implants: study protocol for a randomized controlled trial.

PubMed

Calon, Tim G A; van Hoof, Marc; van den Berge, Herbert; de Bruijn, Arthur J G; van Tongeren, Joost; Hof, Janny R; Brunings, Jan Wouter; Jonhede, Sofia; Anteunis, Lucien J C; Janssen, Miranda; Joore, Manuela A; Holmberg, Marcus; Johansson, Martin L; Stokroos, Robert J

2016-11-09

Over the last years, less invasive surgical techniques with soft tissue preservation for bone conduction hearing implants (BCHI) have been introduced such as the linear incision technique combined with a punch. Results using this technique seem favorable in terms of rate of peri-abutment dermatitis (PAD), esthetics, and preservation of skin sensibility. Recently, a new standardized surgical technique for BCHI placement, the Minimally Invasive Ponto Surgery (MIPS) technique has been developed by Oticon Medical AB (Askim, Sweden). This technique aims to standardize surgery by using a novel surgical instrumentation kit and minimize soft tissue trauma. A multicenter randomized controlled trial is designed to compare the MIPS technique to the linear incision technique with soft tissue preservation. The primary investigation center is Maastricht University Medical Center. Sixty-two participants will be included with a 2-year follow-up period. Parameters are introduced to quantify factors such as loss of skin sensibility, dehiscence of the skin next to the abutment, skin overgrowth, and cosmetic results. A new type of sampling method is incorporated to aid in the estimation of complications. To gain further understanding of PAD, swabs and skin biopsies are collected during follow-up visits for evaluation of the bacterial profile and inflammatory cytokine expression. The primary objective of the study is to compare the incidence of PAD during the first 3 months after BCHI placement. Secondary objectives include the assessment of parameters related to surgery, wound healing, pain, loss of sensibility of the skin around the implant, implant extrusion rate, implant stability measurements, dehiscence of the skin next to the abutment, and esthetic appeal. Tertiary objectives include assessment of other factors related to PAD and a health economic evaluation. This is the first trial to compare the recently developed MIPS technique to the linear incision technique with soft tissue preservation for BCHI surgery. Newly introduced parameters and sampling method will aid in the prediction of results and complications after BCHI placement. Registered at the CCMO register in the Netherlands on 24 November 2014: NL50072.068.14 . Retrospectively registered on 21 April 2015 at ClinicalTrials.gov: NCT02438618 . This trial is sponsored by Oticon Medical AB.

Abduction of Arm Facilitates Correction of Kinked Peel-Away Sheath During Subclavian Central Line Placement.

PubMed

Kim, Sunghoon

2015-12-01

A tunneled central line catheter placement using a subclavian vein approach can be complicated by an occurrence of peel-away sheath kink which prevents the advancement of the catheter through the sheath. The kink is created due to the angular junction of subclavian and brachiocephalic veins which meet at 90 degree angle. A technique is described which corrects the peel-away sheath kink by extending the subclavian/brachiocephalic vein angle to greater than 90 degrees by abducting the patient's arm. Copyright © 2015 Elsevier Inc. All rights reserved.

Endovascular Treatment of Blunt Traumatic Abdominal Aortic Occlusion With Kissing Stent Placement

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

Idoguchi, Koji, E-mail: idoguchi@ares.eonet.ne.jp; Yamaguchi, Masato; Okada, Takuya

Blunt traumatic abdominal aortic dissection is extremely rare and potentially deadly. We present the case of a 62-year-old man involved in a frontal car crash. After emergency undergoing laparotomy for bowel injuries, he was referred to our hospital due to acute ischemia of bilateral lower extremities on day 3 after the trauma. Computed tomography and aortography showed an aortobiiliac dissection with complete occlusion. This injury was successfully treated by endovascular treatment with 'kissing'-technique stent placement, which appears to be a safe, effective, and minimally invasive treatment.

Molecular Interactions of the Min Protein System Reproduce Spatiotemporal Patterning in Growing and Dividing Escherichia coli Cells.

PubMed

Walsh, James C; Angstmann, Christopher N; Duggin, Iain G; Curmi, Paul M G

2015-01-01

Oscillations of the Min protein system are involved in the correct midcell placement of the divisome during Escherichia coli cell division. Based on molecular interactions of the Min system, we formulated a mathematical model that reproduces Min patterning during cell growth and division. Specifically, the increase in the residence time of MinD attached to the membrane as its own concentration increases, is accounted for by dimerisation of membrane-bound MinD and its interaction with MinE. Simulation of this system generates unparalleled correlation between the waveshape of experimental and theoretical MinD distributions, suggesting that the dominant interactions of the physical system have been successfully incorporated into the model. For cells where MinD is fully-labelled with GFP, the model reproduces the stationary localization of MinD-GFP for short cells, followed by oscillations from pole to pole in larger cells, and the transition to the symmetric distribution during cell filamentation. Cells containing a secondary, GFP-labelled MinD display a contrasting pattern. The model is able to account for these differences, including temporary midcell localization just prior to division, by increasing the rate constant controlling MinD ATPase and heterotetramer dissociation. For both experimental conditions, the model can explain how cell division results in an equal distribution of MinD and MinE in the two daughter cells, and accounts for the temperature dependence of the period of Min oscillations. Thus, we show that while other interactions may be present, they are not needed to reproduce the main characteristics of the Min system in vivo.

Method and apparatus for assembling a permanent magnet pole assembly

DOEpatents

Carl, Jr., Ralph James; Bagepalli, Bharat Sampathkumaran [Niskayuna, NY; Jansen, Patrick Lee [Scotia, NY; Dawson, Richard Nils [Voorheesville, NY; Qu, Ronghai [Clifton Park, NY; Avanesov, Mikhail Avramovich [Moscow, RU

2009-08-11

A pole assembly for a rotor, the pole assembly includes a permanent magnet pole including at least one permanent magnet block, a plurality of laminations including a pole cap mechanically coupled to the pole, and a plurality of laminations including a base plate mechanically coupled to the pole.

Island custom blocking technique

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

Carabetta, R.J.

The technique of Island blocking is being used more frequently since the advent of our new head and neck blocking techniques and the implementation of a newly devised lung protocol. The system presented affords the mould room personnel a quick and accurate means of island block fabrication without the constant remeasuring or subtle shifting to approximate correct placement. The cookie cutter is easily implemented into any department's existing block cutting techniques. The device is easily and inexpensively made either in a machine shop or acquired by contacting the author.

Posterior Mesh Tracheoplasty for Cervical Tracheomalacia: A Novel Trachea-Preserving Technique.

PubMed

Wilson, Jennifer L; Folch, Erik; Kent, Michael S; Majid, Adnan; Gangadharan, Sidhu P

2016-01-01

Tracheal resection or placement of airway prostheses (stents, tracheostomy tubes, or T tubes) are techniques currently used to treat severe cervical tracheomalacia. We have developed a new technique to secure a polypropylene splint to the posterior membrane of the cervical trachea in a patient with diffuse, acquired tracheobronchomalacia. This novel posterior tracheoplasty avoids anastomotic and intraluminal adverse events that may occur with existing techniques. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Entrapment of Guide Wire in an Inferior Vena Cava Filter: A Technique for Removal

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

Abdel-Aal, Ahmed Kamel, E-mail: akamel@uabmc.edu; Saddekni, Souheil; Hamed, Maysoon Farouk

Entrapment of a central venous catheter (CVC) guide wire in an inferior vena cava (IVC) filter is a rare, but reported complication during CVC placement. With the increasing use of vena cava filters (VCFs), this number will most likely continue to grow. The consequences of this complication can be serious, as continued traction upon the guide wire may result in filter dislodgement and migration, filter fracture, or injury to the IVC. We describe a case in which a J-tipped guide wire introduced through a left subclavian access without fluoroscopic guidance during CVC placement was entrapped at the apex of anmore » IVC filter. We describe a technique that we used successfully in removing the entrapped wire through the left subclavian access site. We also present simple useful recommendations to prevent this complication.« less

Wiring economy and volume exclusion determine neuronal placement in the Drosophila brain.

PubMed

Rivera-Alba, Marta; Vitaladevuni, Shiv N; Mishchenko, Yuriy; Mischenko, Yuriy; Lu, Zhiyuan; Takemura, Shin-Ya; Scheffer, Lou; Meinertzhagen, Ian A; Chklovskii, Dmitri B; de Polavieja, Gonzalo G

2011-12-06

Wiring economy has successfully explained the individual placement of neurons in simple nervous systems like that of Caenorhabditis elegans [1-3] and the locations of coarser structures like cortical areas in complex vertebrate brains [4]. However, it remains unclear whether wiring economy can explain the placement of individual neurons in brains larger than that of C. elegans. Indeed, given the greater number of neuronal interconnections in larger brains, simply minimizing the length of connections results in unrealistic configurations, with multiple neurons occupying the same position in space. Avoiding such configurations, or volume exclusion, repels neurons from each other, thus counteracting wiring economy. Here we test whether wiring economy together with volume exclusion can explain the placement of neurons in a module of the Drosophila melanogaster brain known as lamina cartridge [5-13]. We used newly developed techniques for semiautomated reconstruction from serial electron microscopy (EM) [14] to obtain the shapes of neurons, the location of synapses, and the resultant synaptic connectivity. We show that wiring length minimization and volume exclusion together can explain the structure of the lamina microcircuit. Therefore, even in brains larger than that of C. elegans, at least for some circuits, optimization can play an important role in individual neuron placement. Copyright © 2011 Elsevier Ltd. All rights reserved.

Parametric study of sensor placement for vision-based relative navigation system of multiple spacecraft

NASA Astrophysics Data System (ADS)

Jeong, Junho; Kim, Seungkeun; Suk, Jinyoung

2017-12-01

In order to overcome the limited range of GPS-based techniques, vision-based relative navigation methods have recently emerged as alternative approaches for a high Earth orbit (HEO) or deep space missions. Therefore, various vision-based relative navigation systems use for proximity operations between two spacecraft. For the implementation of these systems, a sensor placement problem can occur on the exterior of spacecraft due to its limited space. To deal with the sensor placement, this paper proposes a novel methodology for a vision-based relative navigation based on multiple position sensitive diode (PSD) sensors and multiple infrared beacon modules. For the proposed method, an iterated parametric study is used based on the farthest point optimization (FPO) and a constrained extended Kalman filter (CEKF). Each algorithm is applied to set the location of the sensors and to estimate relative positions and attitudes according to each combination by the PSDs and beacons. After that, scores for the sensor placement are calculated with respect to parameters: the number of the PSDs, number of the beacons, and accuracy of relative estimates. Then, the best scoring candidate is determined for the sensor placement. Moreover, the results of the iterated estimation show that the accuracy improves dramatically, as the number of the PSDs increases from one to three.

Impact of Ultrasound on Short Peripheral Intravenous Catheter Placement on Vein Thrombosis Risk.

PubMed

Holder, Max R; Stutzman, Sonja E; Olson, DaiWai M

Approximately 90% of hospitalized patients have a short peripheral intravenous catheter (SPC) placed. Methods of inserting the catheter have evolved over time and now include the use of ultrasound (US)-guided procedures for placement. Little is known about the impact that US-guided procedures have on the vein. This study compared the rate of venous thrombosis in patients with and without US-guided catheter placement. This prospective, single-blind, observational study assessed for venous thrombosis in 153 veins from 135 patients. Veins were evaluated by a research nurse blinded to the method of placement between 48 and 72 hours after the SPC was placed. The Fisher exact test showed a significant difference between vessel compressibility and catheter insertion method (P = .0012). The proportion of noncompressible veins was significantly greater when US was used in comparison with freehand SPC insertion. The Mantel-Haenszel chi-square value of 10.34 (P = .0013) showed that US insertion technique is associated with a higher likelihood of noncompressible veins. This pilot study provides compelling evidence that the use of US to assist with catheter placement is associated with a higher rate of noncompressible veins at day 2 or 3. Further studies are needed with a larger sample to determine the generalizability of the results from this pilot study.

Optometric measurements predict performance but not comfort on a virtual object placement task with a stereoscopic three-dimensional display

NASA Astrophysics Data System (ADS)

McIntire, John P.; Wright, Steve T.; Harrington, Lawrence K.; Havig, Paul R.; Watamaniuk, Scott N. J.; Heft, Eric L.

2014-06-01

Twelve participants were tested on a simple virtual object precision placement task while viewing a stereoscopic three-dimensional (S3-D) display. Inclusion criteria included uncorrected or best corrected vision of 20/20 or better in each eye and stereopsis of at least 40 arc sec using the Titmus stereotest. Additionally, binocular function was assessed, including measurements of distant and near phoria (horizontal and vertical) and distant and near horizontal fusion ranges using standard optometric clinical techniques. Before each of six 30 min experimental sessions, measurements of phoria and fusion ranges were repeated using a Keystone View Telebinocular and an S3-D display, respectively. All participants completed experimental sessions in which the task required the precision placement of a virtual object in depth at the same location as a target object. Subjective discomfort was assessed using the simulator sickness questionnaire. Individual placement accuracy in S3-D trials was significantly correlated with several of the binocular screening outcomes: viewers with larger convergent fusion ranges (measured at near distance), larger total fusion ranges (convergent plus divergent ranges, measured at near distance), and/or lower (better) stereoscopic acuity thresholds were more accurate on the placement task. No screening measures were predictive of subjective discomfort, perhaps due to the low levels of discomfort induced.

Double Y-stenting for tracheobronchial stenosis.

PubMed

Oki, Masahide; Saka, Hideo

2012-12-01

The purpose of the present study was to evaluate the feasibility, efficacy and safety of the double Y-stenting technique, by which silicone Y-stents are placed on both the main carina and another peripheral carina, for patients with tracheobronchial stenosis. Under general anaesthesia, using rigid and flexible bronchoscopes, a Dumon™ Y-stent (Novatech, La Ciotat, France) was first placed on the primary right or secondary left carina followed by another Y-stent on the main carina so as to insert the bronchial limb of the stent into the first Y-stent. Patients who underwent double Y-stent placement during 3 yrs and 1 month in a single centre were retrospectively reviewed. In the study period, 93 patients underwent silicone stent placement and 12 (13%) underwent double Y-stent placement (11 for right and one for left bronchus). A combination of Y-stents, 14 × 10 × 10 mm and 16 × 13 × 13 mm in outer diameter, were most frequently used. Dyspnoea was relieved in all patients. Six out of seven patients with supplemental oxygen before stent placement could be discharged without supplemental oxygen. Median survival after stenting was 94.5 days. One pneumothorax and one granuloma formation occurred. Double Y-stent placement for patients with tracheobronchial stenosis was technically feasible, effective and acceptably safe.

The effects of TV unhealthy food brand placement on children. Its separate and joint effect with advertising.

PubMed

Uribe, Rodrigo; Fuentes-García, Alejandra

2015-08-01

This paper examines the effect of unhealthy food brand placement on children across different age groups (9, 12 and 15 year-old children). Results show that both brand awareness, and the behavioral disposition (toward junk food and McDonald's) increased when children were exposed to this marketing technique (in comparison with the control group). In the case of age, older groups (12-15) performed better in brand awareness, but scored lower in behavioral disposition than the 9-year-old group. Moreover, the joint use of advertising and placement (synergy) increased the effect of these communication tactics on children. Results are discussed in terms of previous results of the studies providing evidence of the influence of promotional tools of junk food on children. Copyright © 2015. Published by Elsevier Ltd.

POD-based constrained sensor placement and field reconstruction from noisy wind measurements: A perturbation study

DOE PAGES

Zhang, Zhongqiang; Yang, Xiu; Lin, Guang

2016-04-14

Sensor placement at the extrema of Proper Orthogonal Decomposition (POD) is efficient and leads to accurate reconstruction of the wind field from a limited number of measure- ments. In this paper we extend this approach of sensor placement and take into account measurement errors and detect possible malfunctioning sensors. We use the 48 hourly spa- tial wind field simulation data sets simulated using the Weather Research an Forecasting (WRF) model applied to the Maine Bay to evaluate the performances of our methods. Specifically, we use an exclusion disk strategy to distribute sensors when the extrema of POD modes are close.more » It turns out that this strategy can also reduce the error of recon- struction from noise measurements. Also, by a cross-validation technique, we successfully locate the malfunctioning sensors.« less

A virtual reality based simulator for learning nasogastric tube placement.

PubMed

Choi, Kup-Sze; He, Xuejian; Chiang, Vico Chung-Lim; Deng, Zhaohong

2015-02-01

Nasogastric tube (NGT) placement is a common clinical procedure where a plastic tube is inserted into the stomach through the nostril for feeding or drainage. However, the placement is a blind process in which the tube may be mistakenly inserted into other locations, leading to unexpected complications or fatal incidents. The placement techniques are conventionally acquired by practising on unrealistic rubber mannequins or on humans. In this paper, a virtual reality based training simulation system is proposed to facilitate the training of NGT placement. It focuses on the simulation of tube insertion and the rendering of the feedback forces with a haptic device. A hybrid force model is developed to compute the forces analytically or numerically under different conditions, including the situations when the patient is swallowing or when the tube is buckled at the nostril. To ensure real-time interactive simulations, an offline simulation approach is adopted to obtain the relationship between the insertion depth and insertion force using a non-linear finite element method. The offline dataset is then used to generate real-time feedback forces by interpolation. The virtual training process is logged quantitatively with metrics that can be used for assessing objective performance and tracking progress. The system has been evaluated by nursing professionals. They found that the haptic feeling produced by the simulated forces is similar to their experience during real NGT insertion. The proposed system provides a new educational tool to enhance conventional training in NGT placement. Copyright © 2014 Elsevier Ltd. All rights reserved.

Colorimetric carbon dioxide detector to determine accidental tracheal feeding tube placement.

PubMed

Howes, Daniel W; Shelley, Eric S; Pickett, William

2005-04-01

To determine the accuracy of colorimetric CO2 detection compared to the reference standard two-step radiological confirmation of feeding tube position. A prospective study was conducted with patients presenting to a 21-bed medical-surgical intensive care unit. An adapter was developed using an endotracheal tube adapter to connect a colorimetric CO2 detector to a feeding tube in an airtight manner. In part I of the study a feeding tube connected to the colorimeter was inserted into the endotracheal tubes of ten ventilated patients to test the device's ability to detect tracheal placement. In part II patients undergoing feeding tube insertion had tube position confirmed with the colorimeter as well as the reference standard two-step x-ray. In phase I the colorimeter correctly identified tracheal placement in all ten patients. In phase II 93/100 procedures ultimately were eligible; the colorimeter had a sensitivity of 0.88 (95% confidence interval: 0.65-1.00) and specificity of 0.99 (0.97-1.00). The device missed one of the eight tracheal placements. Agreement between the colorimeter and two-step x-ray interpretations was excellent (Kappa 0.86; standard error 0.10). We describe a novel, convenient method to confirm esophageal feeding tube placement. The device is easily assembled and inexpensive, but should not be reused. Colorimetric determination of tracheal feeding tube placement with this device has excellent agreement with the reference standard two-step radiological technique.

The three-dimensional reconstruction of the jaw with "bone slat technique" in conjunction with third molar removal.

PubMed

Santagata, Mario; Cecere, Atirge; Prisco, Rosario V E; Tartaro, Gianpaolo; D'Amato, Salvatore

2017-01-01

The purpose of this study was to report the outcome of the management of both horizontal and vertical defects of alveolar crest using the bone slat technique approach in conjunction with third molar removal prior to implant placement in the aesthetic area. We present a 20-year-old female patient who lost a maxillary lateral incisor. The objective of treatment was to replace the lateral incisor with an implant-supported crown restoration without interfering with the integrity and topography of the adjacent gingival tissues. Because the future implant site showed horizontal and vertical bone defect the Authors decided to perform bone regeneration. The need for such bone augmentation in the younger patient often coincides with the timing for third molar removal. By combining third molar extraction with bone harvest and alveolar grafting, the patient undergoes only one surgical approach. The bone height (9.5 mm) and width (5.7 mm) were measured at the point of interest (tooth 12) both before and after implant placement in the reconstructed panoramic and parasagittal views by Cone Beam Computed Tomography (CBCT) scan. The final results demonstrated an increase in length of 5 mm after bone slat technique (from 9.5 mm to 13.5 mm) and an increase in width of 1 mm (from 5.7 mm to 6.7 mm). ISQ measurements were recorded at the time of implant placement (the mean was: 68.5) and immediately after individualized screw-retained provisional crown (the mean was: 77). This technique is reliable and aesthetic and functional results appear to be stable and respect this requisite: simple and fast graft harvesting and low risk of morbidity especially in conjunction with third molar removal.

Basic research for the geodynamics program

NASA Technical Reports Server (NTRS)

1984-01-01

Some objectives of this geodynamic program are: (1) optimal utilization of laser and VLBI observations as reference frames for geodynamics, (2) utilization of range difference observations in geodynamics, and (3) estimation techniques in crustal deformation analysis. The determination of Earth rotation parameters from different space geodetic systems is studied. Also reported on is the utilization of simultaneous laser range differences for the determination of baseline variation. An algorithm for the analysis of regional or local crustal deformation measurements is proposed along with other techniques and testing procedures. Some results of the reference from comparisons in terms of the pole coordinates from different techniques are presented.

Mapping 180° polar domains using electron backscatter diffraction and dynamical scattering simulations

DOE PAGES

Burch, Matthew J.; Fancher, Chris M.; Patala, Srikanth; ...

2016-11-18

A novel technique, which directly and nondestructively maps polar domains using electron backscatter diffraction (EBSD) is described and demonstrated. Through dynamical diffraction simulations and quantitative comparison to experimental EBSD patterns, the absolute orientation of a non-centrosymmetric crystal can be determined. With this information, the polar domains of a material can be mapped. The technique is demonstrated by mapping the non-ferroelastic, or 180°, ferroelectric domains in periodically poled LiNbO 3 single crystals. Furthermore, the authors demonstrate the possibility of mapping polarity using this technique in other polar materials system.

Stress wave nondestructive evaluation of Douglas-fir peeler cores

Treesearch

Robert J. Ross; John I. Zerbe; Xiping Wang; David W. Green; Roy F. Pellerin

2005-01-01

With the need for evaluating the utilization of veneer peeler log cores in higher value products and the increasing importance of utilizing round timbers in poles, posts, stakes, and building construction components, we conducted a cooperative project to verify the suitability of stress wave nondestructive evaluation techniques for assessing peeler cores and some...

Versatile solid-state relay

NASA Technical Reports Server (NTRS)

Fox, D. A.

1977-01-01

Solid-state relay (SSR), containing multinode control logic, is operated as normally open, normally closed, or latched. Moreover several can be paralleled to form two-pole or double-throw relays. Versatile unit ends need to design custom control circuit for every relay application. Technique can be extended to incorporate selectable time delay, on operation or release, or pulsed output.

Authentication Based on Pole-zero Models of Signature Velocity

PubMed Central

Rashidi, Saeid; Fallah, Ali; Towhidkhah, Farzad

2013-01-01

With the increase of communication and financial transaction through internet, on-line signature verification is an accepted biometric technology for access control and plays a significant role in authenticity and authorization in modernized society. Therefore, fast and precise algorithms for the signature verification are very attractive. The goal of this paper is modeling of velocity signal that pattern and properties is stable for persons. With using pole-zero models based on discrete cosine transform, precise method is proposed for modeling and then features is founded from strokes. With using linear, parzen window and support vector machine classifiers, the signature verification technique was tested with a large number of authentic and forgery signatures and has demonstrated the good potential of this technique. The signatures are collected from three different database include a proprietary database, the SVC2004 and the Sabanci University signature database benchmark databases. Experimental results based on Persian, SVC2004 and SUSIG databases show that our method achieves an equal error rate of 5.91%, 5.62% and 3.91% in the skilled forgeries, respectively. PMID:24696797

Measurement of Hydrodynamic Growth near Peak Velocity in an Inertial Confinement Fusion Capsule Implosion using a Self-Radiography Technique

NASA Astrophysics Data System (ADS)

Pickworth, L. A.; Hammel, B. A.; Smalyuk, V. A.; MacPhee, A. G.; Scott, H. A.; Robey, H. F.; Landen, O. L.; Barrios, M. A.; Regan, S. P.; Schneider, M. B.; Hoppe, M.; Kohut, T.; Holunga, D.; Walters, C.; Haid, B.; Dayton, M.

2016-07-01

First measurements of hydrodynamic growth near peak implosion velocity in an inertial confinement fusion (ICF) implosion at the National Ignition Facility were obtained using a self-radiographing technique and a preimposed Legendre mode 40, λ =140 μ m , sinusoidal perturbation. These are the first measurements of the total growth at the most unstable mode from acceleration Rayleigh-Taylor achieved in any ICF experiment to date, showing growth of the areal density perturbation of ˜7000 × . Measurements were made at convergences of ˜5 to ˜10 × at both the waist and pole of the capsule, demonstrating simultaneous measurements of the growth factors from both lines of sight. The areal density growth factors are an order of magnitude larger than prior experimental measurements and differed by ˜2 × between the waist and the pole, showing asymmetry in the measured growth factors. These new measurements significantly advance our ability to diagnose perturbations detrimental to ICF implosions, uniquely intersecting the change from an accelerating to decelerating shell, with multiple simultaneous angular views.

Measurement of hydrodynamic growth near peak velocity in an inertial confinement fusion capsule implosion using a self-radiography technique

DOE PAGES

Pickworth, L. A.; Hammel, B. A.; Smalyuk, V. A.; ...

2016-07-11

First measurements of hydrodynamic growth near peak implosion velocity in an inertial confinement fusion (ICF) implosion at the National Ignition Facility were obtained using a self-radiographing technique and a preimposed Legendre mode 40, λ = 140 μm, sinusoidal perturbation. These are the first measurements of the total growth at the most unstable mode from acceleration Rayleigh-Taylor achieved in any ICF experiment to date, showing growth of the areal density perturbation of ~7000×. Measurements were made at convergences of ~5 to ~10× at both the waist and pole of the capsule, demonstrating simultaneous measurements of the growth factors from both linesmore » of sight. The areal density growth factors are an order of magnitude larger than prior experimental measurements and differed by ~2× between the waist and the pole, showing asymmetry in the measured growth factors. As a result, these new measurements significantly advance our ability to diagnose perturbations detrimental to ICF implosions, uniquely intersecting the change from an accelerating to decelerating shell, with multiple simultaneous angular views.« less

Very high energy gamma astronomy at the South Pole

NASA Astrophysics Data System (ADS)

Landi, G.

1991-07-01

The Air Cherenkov Technique (ACT) is a very important tool to extend our present knowledge on very high energy (VHE) gamma emission from compact astrophysical sources. To overcome the intrinsic limitations of this technique, we are testing the possibility of installing an ACT Telescope at the South Pole. This site is ideal for several reasons: The long polar night permits almost continuous ovservation of a source (up to 400 hours per month and 1700 hours per year). The circumpolarity of the sky simplifies data analysis. The region of the sky is particularly rich in candidate sources. To test the effectiveness of the site, we installed a prototype telescope in the austral summer of 1989-1990. The prototype started to operate in May 1990. Bartol, Firenze, Purdue, Smithsonian, Wisconsin Collaboration. Members are: M. Pomerantz, Bartol; G. Barbagli, G. Castellini, G. Landi, M. Salvati, Firenze; J. Gaidos, F. Loeffler, G. Sembrosky, C. Wilson, G. Zirnstein, Purdue Univ.; P. Slane, A. Szentgyorgy, T.C. Weekes, Smithsonian; U. Camerini, K. Engel, M. Frankowski, W.F. Fry, F. Halzen, J. Jacobsen, M. Jaworski, A. Kenter, R. March, R. Morse, Univ. of Wisconsin

Studies on Automated Manufacturing of High Performance Composites

NASA Technical Reports Server (NTRS)

Cano, R. J.; Belvin, H. L.; Hulcher, A. B.; Grenoble, R. W.

2001-01-01

The NASA Langley Research Center fiber placement facility has proven to be a valuable asset for obtaining data, experience, and insights into the automated fabrication of high performance composites. The facility consists of two automated devices: an Asea Brown Boveri (ABB) robotic arm with a modified heated head capable of hot gas and focused infrared heating and a 7' x 17' gantry containing a feeder head, rotating platform, focused infrared lamp and e-beam gun. While uncured thermoset tow and tape, e.g., epoxy and cyanate prepreg, can be placed with a robot, the placement facility s most powerful attribute is the ability to place thermoplastic and e-beam curable material to net shape. In recent years, ribbonizing techniques have been developed to make high quality thermoplastic and thermoset dry material forms to the standards required for robotic placement. A variety of composites have been fabricated from these ribbons by heated head tow and tape placement including both flat plates and cylinders. Composite mechanical property values of the former were between 85 and 100 percent of those obtained by hand lay-up/autoclave processing.

Laser speckle imaging to improve clinical outcomes for patients with trigeminal neuralgia undergoing radiofrequency thermocoagulation.

PubMed

Ringkamp, Matthias; Wooten, Matthew; Carson, Benjamin S; Lim, Michael; Hartke, Timothy; Guarnieri, Michael

2016-02-01

Percutaneous treatments for trigeminal neuralgia are safe, simple, and effective for achieving good pain control. Procedural risks could be minimized by using noninvasive imaging techniques to improve the placement of the radiofrequency thermocoagulation probe into the trigeminal ganglion. Positioning of a probe is crucial to maximize pain relief and to minimize unwanted side effects, such as denervation in unaffected areas. This investigation examined the use of laser speckle imaging during probe placement in an animal model. This preclinical safety study used nonhuman primates, Macaca nemestrina (pigtail monkeys), to examine whether real-time imaging of blood flow in the face during the positioning of a coagulation probe could monitor the location and guide the positioning of the probe within the trigeminal ganglion. Data from 6 experiments in 3 pigtail monkeys support the hypothesis that laser imaging is safe and improves the accuracy of probe placement. Noninvasive laser speckle imaging can be performed safely in nonhuman primates. Because improved probe placement may reduce morbidity associated with percutaneous rhizotomies, efficacy trials of laser speckle imaging should be conducted in humans.

Quantitative Feedback Technique (QFT): Bridging the Gap

DTIC Science & Technology

2003-05-01

with Eq. (2) illustrates: (a) the effect of changes of the uncertainty set P(s) upon the output of the closed -loop control system is reduced by the...Bridging the Gap root-locus technique the dominant closed -loop poles are determined for a ζ= 0.45. Table 3 presents the required value of Kx and...degree of decoupling will have been enhanced. Method 1 is then more readily applicable, with the additional benefit of reduced closed -loop BW. E.R.2

Sequential lift and suture technique for post-LASIK corneal striae.

PubMed

Mackool, Richard J; Monsanto, Vivian R

2003-04-01

We describe a surgical technique to manage persistent corneal striae after laser in situ keratomileusis (LASIK). The sequential lift and suture technique reduces the time required for LASIK, eliminates the need to fixate the flap with forceps during suturing, and increases the accuracy of suture placement. The results in 10 eyes (9 patients) showed complete resolution of striae with improvement in subjective symptoms (glare and blurred vision) and best corrected visual acuity.

Endoscopic stenting versus surgical colostomy for the management of malignant colonic obstruction: comparison of hospital costs and clinical outcomes.

PubMed

Varadarajulu, Shyam; Roy, Ann; Lopes, Tercio; Drelichman, Ernesto R; Kim, Micheline

2011-07-01

Although stent placement is increasingly performed, colostomy still is considered the gold standard for emergent relief of malignant colonic obstruction (MCO). This study aimed to compare hospital costs and clinical outcomes between patients undergoing colostomy and those undergoing stenting for the management of MCO. A retrospective claims analysis of the Medicare Provider Analysis and Review (MedPAR) data set was conducted to identify inpatient hospitalizations for colostomy or stent placement for the treatment of colon cancer (2007-2008). The outcomes evaluated using MedPAR compared the total length of hospital stay (LOS) and the costs associated with both techniques. Because MedPAR is a claims data set that does not provide outcomes at a patient level, a single-institution retrospective case-control study was conducted in which each stent placement patient was matched with two colostomy patients during the same period. Outcome measures (institutional data) were used to compare rates of treatment success, postprocedure LOS, and reinterventions between the two cohorts. The MedPAR data evaluated 778 stent placements and 5,868 colostomy hospitalizations. There were no differences in gender, age distribution, or comorbidity between the two groups. Compared with colostomy, the median LOS (8 vs. 12 days; p<0.0001) and the median cost ($15,071 vs. $24,695; p<0.001) per claim were significantly less for stent placement. Stent placement was more commonly performed at urban versus rural hospitals (84% vs. 16%; p<0.0001), teaching versus nonteaching hospitals (56% vs. 44%; p=0.0058) and larger versus smaller institutions (mean bed capacity, 331 vs. 227; p<0.0001). The institution data included 12 patients who underwent stent placement and 24 who underwent colostomy. Although both methods were technically successful, the median postprocedure LOS (2.17 vs. 10.58 days; p=0.0004) and the rate of readmissions for complications (0% vs. 25%; p=0.01) were significantly lower for stent placement. Although the technical and clinical outcomes for colostomy and stent placement appear comparable, stent placement is less costly and associated with shorter LOS and fewer complications. Dissemination of stent placement beyond large teaching hospitals located in urban areas as a treatment for MCO is important given its implications for patient care and resource use.

Treatment of chronic subdural hematomas with subdural evacuating port system placement in the intensive care unit: evolution of practice and comparison with bur hole evacuation in the operating room.

PubMed

Flint, Alexander C; Chan, Sheila L; Rao, Vivek A; Efron, Allen D; Kalani, Maziyar A; Sheridan, William F

2017-12-01

OBJECTIVE The aims of this study were to evaluate a multiyear experience with subdural evacuating port system (SEPS) placement for chronic subdural hematoma (cSDH) in the intensive care unit at a tertiary neurosurgical center and to compare SEPS placement with bur hole evacuation in the operating room. METHODS All cases of cSDH evacuation were captured over a 7-year period at a tertiary neurosurgical center within an integrated health care delivery system. The authors compared the performance characteristics of SEPS and bur hole placement with respect to recurrence rates, change in recurrence rates over time, complications, length of stay, discharge disposition, and mortality rates. RESULTS A total of 371 SEPS cases and 659 bur hole cases were performed (n = 1030). The use of bedside SEPS placement for cSDH treatment increased over the 7-year period, from 14% to 80% of cases. Reoperation within 6 months was higher for the SEPS (15.6%) than for bur hole drainage (9.1%) across the full 7-year period (p = 0.002). This observed overall difference was due to a higher rate of reoperation during the same hospitalization (7.0% for SEPS vs 3.2% for bur hole; p = 0.008). Over time, as the SEPS procedure became more common and modifications of the SEPS technique were introduced, the rate of in-hospital reoperation after SEPS decreased to 3.3% (p = 0.02 for trend), and the difference between SEPS and bur hole recurrence was no longer significant (p = 0.70). Complications were uncommon and were similar between the groups. CONCLUSIONS Overall performance characteristics of bedside SEPS and bur hole drainage in the operating room were similar. Modifications to the SEPS technique over time were associated with a reduced reoperation rate.

Y-shaped bilateral self-expandable metallic stent placement for malignant hilar biliary obstruction: data from a referral center for palliative care.

PubMed

Di Mitri, R; Mocciaro, F

2014-01-01

Malignant hilar strictures are a clinical challenge because of the current therapeutic approach and the poor prognosis. In recent years, self-expandable metallic stents have proven more effective than plastic stents for palliation of malignant hilar strictures, with the bilateral stent-in-stent technique registering a high success rate. We report our experience with Y-shaped endoscopic self-expandable metallic stents placement for treatment of advanced malignant hilar strictures. From April 2009 to August 2012, we prospectively collected data on patients treated with Y-shaped SEMS placement for advanced malignant hilar carcinoma. Data on technical success, clinical success, and complications were collected. Twenty patients (9 males) were treated (mean age 64.2 ± 15.3 years). The grade of malignant hilar strictures according to the Bismuth classification was II in 5 patients (25%), IIIa in 1 (5%), and IV in 14 (70%). The mean bilirubin level was 14.7 ± 4.9 mg/dL. Technical success was achieved in all patients, with a significant reduction in bilirubin levels (2.9 ± 1.7 mg/dL). One patient experienced cholangitis as early complication, while in 2 patients stent ingrowth was observed. No stents migration was recorded. There was no procedure-related mortality. At the end of the follow-up (7.1 ± 3.1 months), 13 of the 20 patients (65%) had died. Our experience confirms endoscopic bilateral self-expandable metallic stents placement with stent-in-stent technique (Y-shaped configuration) as a feasible, effective, and safe procedure for palliation of unresectable malignant hilar strictures.

Wind Tunnel Investigation of the Effects of Surface Porosity and Vertical Tail Placement on Slender Wing Vortex Flow Aerodynamics at Supersonic Speeds

NASA Technical Reports Server (NTRS)

Erickson, Gary E.

2007-01-01

A wind tunnel experiment was conducted in the NASA Langley Research Center (LaRC) Unitary Plan Wind Tunnel (UPWT) to determine the effects of passive surface porosity and vertical tail placement on vortex flow development and interactions about a general research fighter configuration at supersonic speeds. Optical flow measurement and flow visualization techniques were used that featured pressure sensitive paint (PSP), laser vapor screen (LVS), and schlieren, These techniques were combined with conventional electronically-scanned pressure (ESP) and six-component force and moment measurements to quantify and to visualize the effects of flow-through porosity applied to a wing leading edge extension (LEX) and the placement of centerline and twin vertical tails on the vortex-dominated flow field of a 65 cropped delta wing model. Test results were obtained at free-stream Mach numbers of 1.6, 1.8, and 2.1 and a Reynolds number per foot of 2.0 million. LEX porosity promoted a wing vortex-dominated flow field as a result of a diffusion and weakening of the LEX vortex. The redistribution of the vortex-induced suction pressures contributed to large nose-down pitching moment increments but did not significantly affect the vortex-induced lift. The trends associated with LEX porosity were unaffected by vertical tail placement. The centerline tail configuration generally provided more stable rolling moments and yawing moments compared to the twin wing-mounted vertical tails. The strength of a complex system of shock waves between the twin tails was reduced by LEX porosity.

Black-White Differences in Child Maltreatment Reports and Foster Care Placements: A Statistical Decomposition Using Linked Administrative Data.

PubMed

Maloney, Tim; Jiang, Nan; Putnam-Hornstein, Emily; Dalton, Erin; Vaithianathan, Rhema

2017-03-01

Introduction Official statistics have confirmed that relative to their presence in the population and relative to white children, black children have consistently higher rates of contact with child protective services (CPS). We used linked administrative data and statistical decomposition techniques to generate new insights into black and white differences in child maltreatment reports and foster care placements. Methods Birth records for all children born in Allegheny County, Pennsylvania, between 2008 and 2010 were linked to administrative service records originating in multiple county data systems. Differences in rates of involvement with child protective services between black and white children by age 4 were decomposed using nonlinear regression techniques. Results Black children had rates of CPS involvement that were 3 times higher than white children. Racial differences were explained solely by parental marital status (i.e., being unmarried) and age at birth (i.e., predominantly teenage mothers). Adding other covariates did not capture any further racial differences in maltreatment reporting or foster care placement rates, they simply shifted differences already explained by marital status and age to these other variables. Discussion Racial differences in rates of maltreatment reports and foster care placements can be explained by a basic model that adjusts only for parental marital status and age at the time of birth. Increasing access to early prevention services for vulnerable families may reduce disparities in child protective service involvement. Using birth records linked to other administrative data sources provides an important means to developing population-based research.

Emergency cricothyrotomy in confined space airway emergencies: a comparison.

PubMed

Givens, Gregory C; Shelton, Stephen L; Brown, Eric A

2011-08-01

In confined-space airway emergencies, prehospital personnel may need to perform cricothyrotomy when conventional airway techniques cannot be utilized or have failed. This study is a prospective, cross-over, randomized controlled trial that compares two widely-known techniques using two commercially available kits. Twenty residents at Palmetto Health Richland Department of Emergency Medicine participated in the study. Their performance was assessed using the time required to placement and correctness of placement for each device. The residents performed the procedures on an Air-Man™ manikin that had been situated in a confined space.The residents also indicated which kit they would prefer in a confined-space, emergency airway situation. All of the devices were placed in the airway. The mean time to placement for the Melker™ and Quicktrach™ kits was 108.5 seconds and 23.9 seconds, respectively. This yielded a mean difference of 84.5 seconds, which provided a t-statistic of 8.88 (p < 0.0001).There was no evidence of a carry-over effect (p = 0.292) or a period effect (p = 0.973). All residents preferred using the Quicktrach™ kit. Use of the Quicktrach™ kit resulted in the fastest time to placement, was placed correctly in the airway, and was preferred by each of the residents. Its small, simple,and sturdy design, with few parts and easy manipulation, allow the Quicktrach™ to be a valuable option in prehospital situations involving confined spaces. The Melker™ kit, with its many parts, and need for greater manipulation, is not as easily utilized or preferred in a confined space scenario.

A comparison of two implant techniques on patient-based outcome measures: a report of flapless vs. conventional flapped implant placement.

PubMed

Lindeboom, Jerome A; van Wijk, Arjen J

2010-04-01

Flapless implant surgery is considered to offer advantages over the traditional flap access approach. There may be minimized bleeding, decreased surgical times and minimal patient discomfort. Controlled studies comparing patient outcome variables to support these assumptions, however, are lacking. The objective of this clinical study was to compare patient outcome variables using flapless and flapped implant surgical techniques. From January 2008 to October 2008, 16 consecutive patients with edentulous maxillas were included in the study. Patients were randomly allocated to either implant placement with a flapless procedure (eight patients, mean age 54.6 + or - 2.9 years) or surgery with a conventional flap procedure (eight patients, mean age 58.7 + or - 7.2 years). All implants were placed using a Nobel guide CT-guided surgical template. Outcome measures were the Dutch version of the Impact of Event Scale-Revised (IES-R), dental anxiety using the s-DAI and oral health-related quality of life (OHIP-14). Ninety-six implants were successfully placed. All implants were placed as two-phase implants and the after-implant placement dentures were adapted. No differences could be shown between conditions on dental anxiety (s-DAI), emotional impact (IES-R), anxiety, procedure duration or technical difficulty, although the flapless group did score consistently higher. The flap procedure group reported less impact on quality of life and included more patients who reported feeling no pain at all during placement. Differences found in the patient outcome variables do suggest that patients in the flapless implant group had to endure more than patients in the flap group.