“Powered Cheese Wire Technique” for Septal Fenestration in Complex Endovascular Repair for Chronic Thoracoabdominal Aortic Dissection

Purpose Endovascular repair of chronic thoracoabdominal aortic dissection with aneurysmal degeneration presents a therapeutic challenge when one or more visceral branches arise from the false lumen without an adjacent reentry. The chronic dissection flap can be thick and resistant to flap fenestration with standard techniques. Technique The powered cheese wire technique facilitates cutting of a dissection flap using electrical current on a noninsulated through-and-through wire segment. The mid-shaft of the guidewire is denuded and kinked to form the “flying V” configuration. This solution is based on the BASILICA procedure, which uses electrosurgery to split aortic valve tissue lengthwise prior to transcatheter aortic valve replacement to prevent coronary artery obstruction. We demonstrate the technique in a case of branched endovascular aortic repair of a complex thoracoabdominal dissecting aneurysm in which a renal artery from the false lumen was catheterized by creating a powered cheese wire fenestration. Conclusion The powered cheese wire technique is an effective approach to access false lumen originating branches during endovascular aortic repair of chronic aortic dissections.

Estimating the wear rate of diamond cutting wire segment in building stone cutting using SVR and GA_MLP system

As the cutting stone is a wear process, performing this process with diamond pieces' aid can be considered the wear of stone particles bypassing diamond grains on its surface. To better understand this process as well as the conditions governing the cutting diamond grain, it is necessary to familiar with the cutting mechanism along with the affecting parameters. In this matter, predicting the amount of segment consumption plays a prominent role to estimate the production cost as well as to schematize the building stone mines. This paper utilized the data obtained from Carbonate and Granite stones to estimate the amount of consumption of diamond cutting wire segments. To do so, two methods, namely support vector regression (SVR) and genetic algorithm + Multilayer perceptron (GA-MLP) were chosen using the MATLAB software toolboxes in order to estimate the segment erosion. In each of the above algorithms, a lowpass smoothing filter, called Savitzky-Golay was employed on the data. For this purpose, three rock properties including uniaxial compressive strength, Shimazk friction factor, and Young's modulus, were also employed as the model's input. After that, twelve models were constructed and then the segment erosion was estimated as well. Ultimately, the accuracy of the above models was assessed using the coefficient of determination (\({R}^{2}\)), mean square error (MSE), root mean square error (RMSE), mean value absolute error (MAD), mean absolute percentage error (MAPE), and variance of factor analysis (VFA). According to the obtained results, it can be concluded that the SVR approach and the Savitzky-Golay filter with Polynomial Kernel could better estimate the wear rate of the diamond cutting wire segment.

Effectiveness of methods for cleaning arch wire: an in vitro study

The aim of this study was to evaluate various methods of removing bacterial and fungus biofilm, to simulate orthodontic arch wires cleaning before reinsertion in the patients appliance. Rectangular Nickel Titanium (NiTi), Stainless Steel (SS) and Titanium Molybdenum (TMA) wires were divided into five groups, then contaminated with strains of Streptococcus mutans and Candida albicas. Four segments of each group served as control and were not contaminated. Six cleanings methods were used to remove the biofilm: cotton roll and a chemical agent (chlorhexidine, sodium hypochlorite, 70% alcohol), cotton roll and water, steel woll and immersion on enzymatic detergent. There was a control group not decontaminated Then wires were placed in broth separately, and after an incubation period the optical density (OD) was measured, observing whether there was microbial growth. A wire segment of each subgroup of SS 3M® was taken to the Scanning Electron Microscope (SEM) for visualization of the treatment response. The results were submitted to one-way ANOVA test and Tukey post-test. With the exception of 70% alcohol, the disinfection means behaved similarly regardless the type of wire. Two percent Chlorhexidine and 1% Sodium Hypochlorite totally removed the microorganisms while other agents left a high microbial concentration. Chemical cleaning is necessary to remove biofilm in orthodontic wires; 1% Sodium Hypochlorite and 2% Chlorhexidine are good disinfectants for this purpose.

Evaluation of bone loss due to primary occlusal trauma in two experimental models of occlusal overload

Introduction Primary occlusal trauma (OT) is an injury of the periodontium with normal height as a result of occlusal forces which exceed their adaptive capacity. Objective To evaluate, histometrically, the alveolar bone loss in the furcation region of rats experimentally submitted to 2 models of occlusal overload. Material and method 45 animals randomly divided into 3 groups: Occlusal Interference (OI, n = 15) - fixing an orthodontic wire segment on the occlusal surface of the first lower molar; Occlusal Overload (OO, n = 15) - wearing of the cusps of the lower contralateral molars, the second and third molars next to the first molar that had its dimensions maintained; Negative Control (NC, n = 15) - evaluation of the initial dimensions of the periodontal ligament (PL). Five animals / group were sacrificed after 14, 21 and 28 days. Result Intergroup evaluation showed significant bone loss in OI (p<0.001) and OO (p<0.01) compared to NC. OI had significantly higher bone loss compared to OO at 14 (p<0.01), 21 (p <0.01) and 28 days (p<0.01). The intragroup evaluation showed no significant influence of time on bone loss in OI and OO, regardless of the technique used (p>0.05). The thickness of the PL remained stable in NC (p>0.05). Conclusion OI and OO were effective in the experimental reproduction of OT, and OI promoted greater alveolar bone loss compared to OO, showing that the impact of occlusal overload in OI increased the extent of the OT injury.

When the Midline Diastema Is Not Characteristic of the “Ugly Duckling” Stage

This case report presents the interceptive orthodontic treatment of a 9-year, 5-month-old boy with class I malocclusion, a 9.0-mm maxillary midline diastema, and deviation from the midline. The treatment goals were to decrease the magnitude of the diastema and to simulate the characteristics of the “ugly duckling” stage. Braces were placed on the first molars and the maxillary central incisors. The biomechanics of the anchors on the first molars elicited substantial mesial movement of the left central incisor to match the midline. A flat wire segment was bonded onto the palatal surface of the central incisors for retention.

A Possible Failure Mode for Leeward Mooring Lines on a Floating Storage Unit

The floating storage unit Navion Saga at the Volve field in the North Sea suffered from two mooring line breaks in steel wire ropes in 2011. Investigations of the broken ropes indicated that a possible failure mechanism could be high stresses near the wire socket induced by large bending moments in leeward mooring lines. The scope of the current study has been to make a numerical model capable of capturing such behaviour of the steel wire rope and to check if the minimum bending radius could be as low as the rope’s specified minimum bending radius. The numerical model has revealed a possible failure mechanism. The connecting link plate between the upper chain segment and the upper wire segment lies initially on the seabed. When lifted off the seabed, the link plate and the wire socket will fall to the seabed at a higher speed than the upper wire segment. A transverse wave in mooring line plane propagating towards fair-lead is generated when the wire socket hits the seabed. The wave leads to large curvature in the wire near the socket. Sensitivity studies of the governing parameters have been performed to assess the uncertainties of the numerical model. A modified system is presented and it is shown that the phenomenon which is likely to have caused failure in the original system will not occur for the modified one.

Simulation study of solar wind push on a charged wire: basis of solar wind electric sail propulsion

One possibility for propellantless propulsion in space is to use the momentum flux of the solar wind. A way to set up a solar wind sail is to have a set of thin long wires which are kept at high positive potential by an onboard electron gun so that the wires repel and deflect incident solar wind protons. The efficiency of this so-called electric sail depends on how large force a given solar wind exerts on a wire segment and how large electron current the wire segment draws from the solar wind plasma when kept at a given potential. We use 1-D and 2-D electrostatic plasma simulations to calculate the force and present a semitheoretical formula which captures the simulation results. We find that under average solar wind conditions at 1 AU the force per unit length is (5±1×10−8 N/m for 15 kV potential and that the electron current is accurately given by the well-known orbital motion limited (OML) theory cylindrical Langmuir probe formula. Although the force may appear small, an analysis shows that because of the very low weight of a thin wire per unit length, quite high final speeds (over 50 km/s) could be achieved by an electric sailing spacecraft using today's flight-proved components. It is possible that artificial electron heating of the plasma in the interaction region could increase the propulsive effect even further.