Tip Distance Research Articles

Air-side heat transfer characteristics of ambient air vaporizers with various geometric parameters under cryogenic frosting conditions

Ambient air vaporizers (AAVs), which utilize air as a heat source, have been widely used for natural gas regasification. Under cryogenic frosting conditions, the heat transfer performance of AAVs is gradually reduced owing to frost growth on the fin surface. In this study, the heat transfer characteristics of AAVs were measured and analyzed by varying the geometric design parameters and operating variables under cryogenic frosting conditions. The air velocity, relative humidity, and temperature were selected as the operating variables, and the fin height, fin tip distance, and fin pitch were considered as design parameters. The frost growth was accelerated with increasing air velocity, humidity, and temperature under cryogenic frost conditions. Furthermore, as the fin height, fin tip distance, and fin pitch increased, the heat transfer reduction and pressure drop with respect to time decreased owing to the decrease in the blockage ratio. In addition, an empirical correlation for the Nusselt number in AAVs was developed as a function of the operating variables and geometric parameters based on the measured data. The present results can be used as practical design guidelines for AAVs under actual operating conditions.

Cyclic Single Atom Vertical Manipulation on a Nonmetallic Surface.

Motivated by the quest for experimental procedures capable of controlled manipulation of single atoms on surfaces, we set up a computational strategy that explores the cyclical vertical manipulation of a broad set of single atoms on the GaAs(110) surface. First-principles simulations of atomic force microscope tip-sample interactions were performed considering families of GaAs and Au-terminated tip apexes with varying crystalline termination. We identified a subset of tips capable of both picking up and depositing an adatom (Ga, As, Al, and Au) any number of times via a modify-restore cycle that "resets" the apex of the scanning probe to its original structure at the end of each cycle. Manipulation becomes successful within a certain window of lateral and vertical tip distances that are observed to be different for extracting and depositing each atom. A practical experimental protocol of special utility for potential cyclical manipulation of single atoms on a nonmetallic surface is proposed.

Hemodynamic and Anatomical Factors in Arteriovenous Malformation Clinical Presentation: 45 Case Studies.

Hemodynamic factors have been implicated in hemorrhage from cerebral arteriovenous malformations (AVMs). The goal of this endovascular study is to analyze the hemodynamic variability in AVM feeders in a balanced group of ruptured and unruptured AVMs of various sizes and at both superficial and deep locations. We monitored feeder artery pressure (FP) using microcatheters in 45 patients with AVMs (16 with hemorrhage, 29 without) during superselective angiography and AVM embolization. Mean FP was 49 mm Hg. Significant determinants of FP were the systemic pressure (p < 0.001), AVM size (p = 0.03), and the distance of the microcatheter tip from the Circle of Willis (p = 0.06), but not the presence of hemorrhage, patient age, or feeder artery diameter. The FP in ruptured AVMs was 7 mm Hg higher than in unruptured ones (53.8 mm Hg vs. 47.1 mm Hg, p = 0.032). The presence or absence of venous outflow stenosis and the position of the AVM nidus (superficial or deep to the cortical surface) were important anatomical predictors of AVM presentation. The pressure in the feeding artery supplying an AVM is the result of factors which include the systemic arterial pressure, the size of the AVM nidus, and the distance of the AVM from the Circle of Willis. The correlation between these variables makes it difficult to study the risk of hemorrhage as a function of a single factor, which may account for the variation in the conclusions of previous studies.

Near-field scanning optical microscopy of molecular aggregates: The role of light polarization

We consider theoretically near-field absorption spectra of molecular aggregates stemming from a scattering scanning near-field optical microscopy type setup. Our focus is on the dependence on the direction and polarization of the incoming electromagnetic radiation, which induces a Hertz dipole with a specific orientation at the tip-apex. Within a simple description, which is based on the eigenstates of the aggregate, absorption spectra are calculated for the near field created by this dipole. We find that the spatial patterns of the spectra have a strong dependence on the orientation of this tip-dipole, which can be understood by considering three basic functions that only depend on the arrangement of the aggregate and the molecule tip distance, but not on the orientation of the tip-dipole. This allows direct access to spatial dependence of the aggregate eigenstates. For the important cases of one- and two-dimensional systems with parallel molecules, we discuss these spectra in detail. The simple numerically efficient approach is validated by a more detailed description where the incoming radiation and the interaction between the tip and molecules are explicitly taken into account.

Effect of Ducted Multi-Propeller Configuration on Aerodynamic Performance in Quadrotor Drone

Motivated by a bioinspired optimal aerodynamic design of a multi-propeller configuration, here we propose a ducted multi-propeller design to explore the improvement of lift force production and FM efficiency in quadrotor drones through optimizing the ducted multi-propeller configuration. We first conducted a CFD-based study to explore a high-performance duct morphology in a ducted single-propeller model in terms of aerodynamic performance and duct volume. The effect of a ducted multi-propeller configuration on aerodynamic performance is then investigated in terms of the tip distance and the height difference of propellers under a hovering state. Our results indicate that the tip distance-induced interactions have a noticeable effect in impairing the lift force production and FM efficiency but are limited to small tip distances, whereas the height difference-induced interactions have an impact on enhancing the aerodynamic performance over a certain range. An optimal ducted multi-propeller configuration with a minimal tip distance and an appropriate height difference was further examined through a combination of CFD simulations and a surrogate model in a broad-parameter space, which enables a significant improvement in both lift force production and FM efficiency for the multirotor, and thus provides a potential optimal design for ducted multirotor UAVs.

A novel system for teaching the in-plane vascular access technique: A simulation study.

The long-axis in-plane approach is amenable to ultrasound-guided central venous catheterization. However, the long-axis in-plane approach is considered difficult to learn because the needle should remain visible in the ultrasound beam during the procedure. We developed a novel competency-based modular system to acquire the skills for the long-axis in-plane approach. The purpose of this study is to evaluate the efficacy of this system.The study was approved by the local ethics committee. Participants performed ultrasound guided venous catheterization (pre-test), attended a 2-hour hands-on session with the teaching system and were then evaluated again (posttest). The teaching system is a simulator device consisting of an ultrasound probe, a simulated vessel, a needle, and an endoscope connected to a computer to visualize the image inside the simulated vessel. The success rate, visualization of the needle tip, and puncture accuracy were measured before and after training. The puncture accuracy was determined by evaluating the distance of the needle tip and needle shaft from the center of a simulated vessel. Primary outcomes were the success rate and the puncture accuracy. The secondary outcome was needle tip visualization. McNemar test was used to analyze success rate and needle tip visualization. Tukey test was used to analyze puncture accuracy. A P value <.05 was considered statistically significant.Forty-seven participants were enrolled in this study. The success rate was significantly increased (pre-test 79%, posttest 94%, P = .04). Ultrasound images from 42 participants were analyzed for puncture accuracy. Puncture accuracy significantly increased for needle tip distance (P = .03), but not shaft distance (P = .1). The needle tip visualization was significantly improved (P = .02).A novel competency-based teaching system was constructed in a step-by-step manner, which improved needle tip visualization and puncture accuracy, with a higher success rate.

A morphometric study of the thoracolumbar spine spinous process and lamina space in the Chinese.

The aim of the study was to analyse the anatomical parameters of the thoracolumbar spine spinous process and lamina space for Chinese anatomic study, and provide an anatomical reference for its clinical operation. Samples from 24 adult autopsy subjects were obtained from the thoracolumbar spine spinous process and lamina space at levels T1 through L5. Direct measurements were made for the spinous process spacing distance, spinous process length, width, thickness and inclination angle, and the lamina space width and height. 1. Distance of the spine spinous process spacing: Thoracic part: The maximum tip distance was observed at T4~T5 level, and the minimum tip distance was observed at T9~T10 level. The maximum centre distance and root distance were observed at T11~T12 level, and the minimum were observed at T5~T6 level separately. Lumbar part: distance of spinous process spacing in lumbar part showed a decreasing pattern from L1~L2 to L5~S1. 2. Length, width, thickness of the spine spinous process: 1) The length of the spinous process: The upper border gradually increased from T1 to T6 and then decreased till T12 region. The centre region is T8 maximum, T11 minimum. The lower border length showed a decreasing trend from T1 to T12. Lumbar part: The length increased from L1 and reached maximum value at L3. Then, the length decreased gradually to reach minimum value at L5. 2) The width of the spinous process: The width showed an increasing trend from T1 to T12. Lumbar part: Maximum width was seen at L3 and a minimum L5. 3) The thickness of the spinous process: Tip thickness > Centre thickness > Root thickness in each thoracic and lumbar vertebra. Thoracic part: the maximum tip thickness is T1, T7 minimum, The maximum centre thickness is T12, T7 minimum. The maximum root height is T6, T9 minimum. Lumbar part: Maximum tip thickness was seen at L1, and a minimum L3. Maximum centre thickness was seen at L5, and a minimum L2. Maximum root thickness was seen at L2, and a minimum L1. 3. Inclination angle of the spine spinous process: The inclination angle gradually decreased from T1 to T7 to minimum value at T7 and then increased till T12 region. 4. Width and height of lamina space: 1) The width of lamina space: For thoracic part, the data became shorter gradually from T1~T2 to T5~T6, and then increased till to T11~T12. For lumbar part, the width of lamina space increased from T12~L1 to L5~S1. 2) The height of lamina space: In the thoracic vertebrae, the maximum height of centre region was observed at T11~T12 and the minimum mean value was observed at T3~T4. In the lumbar vertebrae, the height of the lamina space was gradually increased from T12~L1 to L5~S1. This study reports morphometric data of the thoracolumbar spine spinous process and lamina space in the Chinese population, which provides an anatomic basis for thoracolumbar spine design of internal fixation, posterior surgery, puncture and epidural anaesthesia.

PD26-07 IMAGE DISTORTION DURING FLEXIBLE URETEROSCOPY: A LABORATORY MODEL COMPARING SUPER PULSE THULIUM FIBER (SPTF) LASER VS HIGH POWER HO:YAG LASER

You have accessJournal of UrologyStone Disease: Surgical Therapy III (PD26)1 Sep 2021PD26-07 IMAGE DISTORTION DURING FLEXIBLE URETEROSCOPY: A LABORATORY MODEL COMPARING SUPER PULSE THULIUM FIBER (SPTF) LASER VS HIGH POWER HO:YAG LASER Caleb S Miller, Bristol B Whiles, David A Duchene, Donald A Neff, and Wilson R Molina Caleb S MillerCaleb S Miller More articles by this author , Bristol B WhilesBristol B Whiles More articles by this author , David A DucheneDavid A Duchene More articles by this author , Donald A NeffDonald A Neff More articles by this author , and Wilson R MolinaWilson R Molina More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002019.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Digital ureteroscopes employ “chip on the tip” technology which allows significant improvement in image resolution. However, image distortion often occurs during laser lithotripsy due to acoustic wave production. We sought to compare the Super Pulse Thulium Fiber (SPTF) laser with the high power Holmium (Ho:YAG) laser in terms of image distortion using variable laser power settings and laser fiber tip distance from the scope’s tip. METHODS: Utilizing a silicone renal model fitted with a 12/14F access sheath, we developed a laboratory model to simulate ureteroscopy. The LithoVue (Boston Scientific), disposable digital flexible ureteroscope was used with 200 micron laser fibers for both the SPTF (Soltive-Olympus) and High power Ho:YAG laser (P120-Lumenis). At defined laser parameters (10, 20, 30, and 40W; short pulse) the laser fiber was slowly retracted toward the tip of the scope during laser activation. Image distortion was identified, and distance from the laser tip to the scope tip was determined. Data from the two lasers were compared utilizing a paired t-test. RESULTS: Image distortion occurred at greater distance with the Ho:YAG compared to SPTF at all laser settings (Table 1). Additionally, higher power (W) was associated with image distortion occurring further from the tip of the scope (p<0.01 for Ho:YAG; p=0.02 for SPFT). At the same power (W) with either 1J or 0.5J, there was no difference in distance for image distortion for the Ho:YAG, but distortion occurred differently with the SPTF (20 and 40W; p<0.01 and p=0.02, respectively). CONCLUSIONS: Increased total power as well as decreased distance between the scope and laser fiber tip results in image distortion during flexible ureteroscopy. Image distortion occurs at a greater distance with the Ho:YAG laser than with SPTF fibers at the same laser settings. SPTF seems to have a better safety profile in terms image distortion and potential scope damage. Further evaluation utilizing Ho:YAG on modulated pulse mode is warranted. Source of Funding: None © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e440-e440 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Caleb S Miller More articles by this author Bristol B Whiles More articles by this author David A Duchene More articles by this author Donald A Neff More articles by this author Wilson R Molina More articles by this author Expand All Advertisement Loading ...

Alterations in Intracardiac Flow Patterns Affect Mitral Leaflets Dynamics in a Model of Ischemic Mitral Regurgitation.

This study was to evaluate the effects of ischemic mitral regurgitation (IMR) on vortex formation and leaflet dynamics using an established porcine infarct model of IMR. Using direct coronary ligation, five animals were subjected to a posterolateral myocardial infarction (MI) followed by an MRI at 12-weeks post MI. MR imaging consisted of 4D time-resolved left ventricular (LV) flow, full coverage 2D LV cine, and high resolution 2D cine of mitral valve dynamics. Five additional naïve animals underwent identical imaging protocols to serve as controls. Image analysis was performed to obtain mitral transvalvular flows as well as LV volumes throughout the cardiac cycle. In addition, anterior to posterior mid-leaflet tip distances were measured throughout the cardiac cycle for determination of temporal leaflet dynamics. It was found IMR caused asymmetric vortex ring formation with the anterior vortex having a lower vorticity relative to its posterior counterpart. In contrast, normal ventricles create symmetric and tightly curled vortices in the basal chamber just underneath the mitral leaflets which conserve kinetic energy and aid in effective ejection. IMR animals were also evaluated for leaflet separation and were found to have a greater leaflet opening and achieved peak vorticity and peak leaflet opening later than control animals. In conclusion, this study shows the effects that altered vortex formation, due to IMR, can have on ventricular filling and leaflet dynamics. These findings have important implications for understanding blood flow through the dilated heart and how ring annuloplasty and volume reduction interventions may influence mitral valve dynamics.

Optimization of The Oxy-Acetyline Gas Cutting Process on Aisi 1045 Steel Material to Produce Minimum Width Kerf

This research is intended to determine the optimum combination of parameters and how much the contribution of the parameters of cutting speed, oxygen gas pressure, and nozzle distance to the width of the cutting kerf. This research was conducted with a method, namely Taguchi Design of Experiments (DoEs) by varying the process factors used in the AISI 1045 steel material cutting process. The control factors in this study consisted of three factors, namely cutting speed, gas pressure, and tip distance. The cutting speed and cutting gas pressure are significant factors in the optimization of the AISI 1045 steel cutting process for minimum kerf width with a contribution of 95.6%, while the tip / nozzle height factor is not significant in the optimization of the AISI 1045 steel cutting process for the kerf width minimum. The optimum parameter values to obtain the minimum kerf width in AISI 1045 steel are cutting speed of 250 mm/min, gas pressure of 3 kgf/cm2, and tip height of 4 mm. Furthermore, the results of the verification tests carried out indicated that the optimal process parameter formula obtained is feasible to use, indicated by the S / N ratio and confidence interval (CI) of prediction and verification that coincide with one another. The optimal process parameter formula can be used as a reference for industrial production activities with a 95% success rate.

Accuracy Comparison of Endotracheal Tube (ETT) Placement Using Chula Formula With Manubrium Sternal Joint (MSJ) Formula

Introduction: Intubation mistakes, such as ETT malposition, will result in serious complications. Endobronchial intubation can cause pneumothorax and contralateral lung collapse (atelectasis). On the contrary, superficial ETT could increase the risk of being released easily, leading to desaturation or even cardiac arrest. A shallow ETT position could cause the compression of the vocal cord and laryngeal nerve by ETT's cuff. An optimal position can be reached if the cuff position is 1.5-2.5 cm under the vocal cord and the tip is 3-5 cm above the carina. Several methods of ETT depth measurement based on airway length data can be an alternative, especially during the COVID-19 era, where the use of a stethoscope to check ETT depth is limited. Objectives: To analyze the accuracy of ETT depth placement using Chula and MSJ formula. Methods and Material: We conducted the prospective comparative analytic research on 50 patients who had elective surgery in GBPT operating room at Dr. Soetomo Hospital Surabaya. The research data during the intubation and FOL (Fyber Optic Laryngoscope) from each patient were height, MSJ length, initial ETT length, the distance of carina-ETT tip, the distance of cuff-vocal cord, and final ETT length. Result and Discussion: In the Chula formula group, the average patients' height was 160.60cm ± 9.738 for men and 157.76 cm ± 8.604 for women. The average MSJ length was 20.28 cm. The application of the Chula formula is more accurate because ETT revision was carried out in only 8.0% of the samples, with an average revision is 0.04. On the other hand, the ETT revision with an average of 0.868 on the MSJ formula group was conducted in 84% of the samples. This research also found a linear correlation between increasing ETT depth and body height. Conclusion: Applying the Chula formula to measure the ETT depth for Indonesian (Javanese) people is more appropriate than the MSJ formula.

Effects of indwelling centrally inserted central catheter on tip location of peripherally inserted central catheter with intracavitary electrocardiogram guidance: A retrospective case-control study.

Intracavity electrocardiogram (IC-ECG) guidance is an effective technology for monitoring the tip locations of centrally inserted central catheters (CICCs) and peripherally inserted central catheters (PICCs). However, for patients with an indwelling CICC, there has been no study on whether the CICC affects PICC tip positioning with IC-ECG guidance. Thirty people with a CICC requiring PICC insertion, matched with age to controls without a CICC. The stability of IC-ECG waveforms, the amplitude of P-waves, and the accuracy of PICC tip location were compared. There was no significant difference in the stability of the IC-ECG waveforms (χ2 = 0.22, p = 0.64). The amplitudes of baseline P-waves and ideal P-waves also showed no significant difference (t1 = 0.06, p1 = 0.96, t2 = 0.80, p2 = 0.43). Neither the accuracy of tip location (χ2 = 1.40, p = 0.50) nor the distance of PICC tip (t = -0.03, p = 0.98) were significantly different. For patients with an indwelling CICC, the position of PICC tip can be accurately determined by the dynamic changes in the P-wave amplitude.

Adult Auditory Brainstem Implant Outcomes and Three-Dimensional Electrode Array Position on Computed Tomography.

Factors contributing to auditory brainstem implant (ABI) outcomes are poorly understood. The aims of this study are to (1) characterize ABI electrode array position on postoperative imaging and (2) determine if variability in position is related to perceptual outcomes. Retrospective cohort study. Subjects were selected from the adult ABI recipient population at Massachusetts Eye and Ear. Postoperative three-dimensional (3D) computed tomography (CT) reconstruction of the head was used to measure ABI array position in 20 adult ABI recipients (17 with Neurofibromatosis Type 2 (NF2) and three non-NF2 recipients). Three-dimensional electrode array position was determined based on angles from the horizontal using posterior and lateral views and on distances between the proximal array tip superiorly from the basion (D1), laterally (D2P) and posteriorly (D2L) from the midline. Array position was correlated with perceptual data (in 15 of the 20 recipients who used their ABI). Perceptual data included the number of electrodes that provided auditory sensation, location and type of side effects, level of speech perception (from no sound to open-set word recognition of monosyllables) and the amount of charge required for auditory perception. Although the 3D orientation of the ABI array exhibited a variety of angles, all arrays were posteriorly tilted from the lateral view and most were medially tilted from the posterior view. ABI position relative to the basion from posterior showed mean distances of 1.71 ± 0.42 and 1.1 ± 0.29 cm for D1 and D2, respectively, and a mean D2 of 1.30 ± 0.45 cm from the lateral view. A strong linear negative correlation was found between the number of active electrodes and the distance of the proximal array tip laterally from the basion (D2P; rs = -0.73, p = 0.006) when measured in the posterior view. Although side effects were experienced in all recipients and varied in type and location across the array, electrodes in the middle part of the array tended to elicit auditory sensations while the proximal and distal tips of the array tended to elicit nonauditory side effects. Arrays with and without low charge thresholds appeared to generally overlap in position. However, the two recipients with the best (open-set) speech perception had low charge thresholds and had arrays that were tilted superiorly in the posterior view. ABI recipients with better speech perception appear to share a profile of arrays that are tilted superiorly as compared to recipients with lower speech perception levels. These ABI recipients have a high number of active electrodes (10 or more) and require less electrical charge on individual electrodes to achieve optimal stimulation.

Modeling the self-penetration process of a bio-inspired probe in granular soils

Soil penetration is an energy-intensive process that is common in both nature and civil infrastructure applications. Many human construction activities involve soil penetration that is typically accomplished through impact-driving, pushing against a reaction mass, excavating, or vibrating using large equipment. This paper presents a numerical investigation into the self-penetration process of a probe that uses an ‘anchor–tip’ burrowing strategy with the goal of extending the mechanics-based understanding of burrower–soil interactions at the physical dimensions and stress levels relevant for civil infrastructure applications. Self-penetration is defined here as the ability of a probe to generate enough anchorage forces to overcome the soil penetration resistance and advance the probe tip to greater depths. 3D Discrete element modeling simulations are employed to understand the self-penetration process of an idealized probe in noncohesive soil along with the interactions between the probe’s anchor and tip. The results indicate that self-penetration conditions improve with simulated soil depth, and favorable probe configurations for self-penetration include shorter anchor–tip distances, anchors with greater length and expansion magnitudes, and anchors with a greater friction coefficient. The results shed light on the scaling of burrowing forces across a range of soil depths relevant to civil infrastructure applications and provide design guidance for future self-penetrating probes.

Using Artificial Neural Networks to Predict Influences of Heterogeneity on Rock Strength at Different Strain Rates.

Pre-existing cracks and associated filling materials cause the significant heterogeneity of natural rocks and rock masses. The induced heterogeneity changes the rock properties. This paper targets the gap in the existing literature regarding the adopting of artificial neural network approaches to efficiently and accurately predict the influences of heterogeneity on the strength of 3D-printed rocks at different strain rates. Herein, rock heterogeneity is reflected by different pre-existing crack and filling material configurations, quantitatively defined by the crack number, initial crack orientation with loading axis, crack tip distance, and crack offset distance. The artificial neural network model can be trained, validated, and tested by finite 42 quasi-static and 42 dynamic Brazilian disc experimental tests to establish the relationship between the rock strength and heterogeneous parameters at different strain rates. The artificial neural network architecture, including the hidden layer number and transfer functions, is optimized by the corresponding parametric study. Once trained, the proposed artificial neural network model generates an excellent prediction accuracy for influences of high dimensional heterogeneous parameters and strain rate on rock strength. The sensitivity analysis indicates that strain rate is the most important physical quantity affecting the strength of heterogeneous rock.

Comparison of Intubation with Chula Formula Method and Manubrium Sternal Joint (MSJ) Formula against Oxygenation and Sore Throat in General Anaesthesia at Dr. Soetomo General Hospital

Intubation is a way to free the airway during general anesthesia procedures, but some severe complications can arise from this procedure, such as desaturation up to the cardiac arrest and brain damage. Another complication that can arise from ETT insertion is a sore throat. Optimal Endotracheal Tube (ETT) depth is a significant concern because of complications associated with ETT malposition. By using the right formula, the incidence of sore throat and desaturation can be minimized. This study compared the Chula formula's intubation method and the Manubrium sternal Joint (MSJ) formula against oxygenation and sore throat under general anesthesia. This research is a prospective comparative analytical study carried out on 50 people aged ≥ 18- ≤ 65 years, with the American Society of Anesthesiology (ASA) I-III, Malampari score I-II and conducted in Dr. Soetomo General Hospital Surabaya's surgical room from September-October 2020. Subjects were divided into two treatment groups: those with ETT depth measurements using the formula Chula and groups with Manubrium Sternal Joint (MSJ). Assessment of ETT tip distance to the carina using a Fiberoptic Laryngoscope (FOL), while oxygenation measured by pulse oxymetry and sore throat using a questionnaire. This study showed optimal oxygenation and minimal sore throat incidence in the Chula formula was better than the MSJ technique. Statistical analysis used the Kolmogorov-Smirnov test. The analysis results showed statistically significant differences (p<0.05). This research concludes that the use of the Chula formula results in optimal oxygenation and minimal sore throat.

Comparative outcomes of Inferior Vena Cava filters placed at bedside using digital radiography versus conventional fluoroscopy

PurposeTo retrospectively assess the outcomes of Inferior Vena Cava (IVC) filters placed in critically ill patients in the ICU at bedside using digital radiograph (DR) guidance with previous cross-sectional imaging for planning, compared to IVC filters placed by conventional fluoroscopy (CF). Method and materialsThe cohort consisted of 129 IVC filter placements; 48 placed at bedside and 81 placed conventionally from July 2015 to September 2016. Patient demographics, indication, radiation exposures, access site, procedural duration, dwell time, and complications were identified by the EMR. IVC Filter positioning with measurements of tip to renal vein distance and lateral filter tilt were performed when cavograms or post placement CTs were available for review. Statistical analysis was performed using Stata IC 11.2. ResultsTechnical success of the procedure was 100% in both groups. Procedural duration was longer at the bedside lasting 14.5 +/- 10.2 versus 6.7 +/- 6.0 ​min (p<0.0001). The bedside DR group had a median radiation exposure of 25 ​mGy (15–35) and the CF group had mean radiation exposure of 256.94 ​mGy +/- 158.6. There was no significant difference in distance of IVC tip to renal vein (p=0.31), mispositioning (p=0.59), degree of filter tilt (p=0.33), or rate of complications (p=0.65) between the two groups. ConclusionIVCF placement at the bedside using DR is comparable to CF with no statistical difference in outcomes based on IVCF positioning, degree of lateral tilt or removal issues. It decreased radiation dose, but with overall increased procedural time.

THREE DIMENSIONAL ASSESSMENT OF MOVEMENT OF SKELETALLY ANCHORED MOLARS DURING LEVELING AND ALIGNMENT STAGE OF FIXED ORTHODONTIC MECHANOTHERAPY

Introduction- Alignment and leveling has been dene as “The tooth movement needed to achieve passive engagement of a plain arch wire of 0.019x0.025 dimension having standard arch form in to a correctly placed 0.022˝ bracket system.''Anchorage is an important consideration in the alignment and leveling stage of orthodontic treatment. Loss of anchorage during this stage is to be considered in the three planes of space. Aims and objectives - Three dimensional assessment of the position of skeletally anchored rst molar teeth and three dimensional assessment of the position of rst molar teeth anchored with conventional trans palatal arch using lateral cephalogram and study models, at the end of leveling and alignment stage of xed orthodontic mechanotherapy and its comparison with pretreatment position.Utimately to nd out by comparing the above measurements whether skeletally anchored molars offer more anchorage than molars anchored with conventional transpalatal arches. Materials and methods- These 30 patients were asked to participate in this study out of which 20 consented. All pre-treatment(T ) patient records were made: o study models, standard lateral cephalograms (Satlec – Pano D), extra oral and intra oral photograph. Miniscrew anchored transpalatalarch (MATPA) was placed in 12 patients(group I) and conventional transpalatal arch in 8 patients (group II). 0.022” stainless steel M.B.T. prescription brackets and tubes ( Nu- Edge, TP Orthodontics) were used and treatment mechanics described by Mc. Laughin, Bennet and Trevisi were followed in all patients. Result - This study attempted a 3-dimensional assessment of molar movement during alignment and leveling stage. The mini screw anchored trans palatal arch (MATPA) was found to offered better anchorage than the conventional trans palatal arch (TPA) .In the sagittal plane angular and linear measurements were found to have signicantly changed after leveling and alignment for conventional TPA group whereas no signicant difference were found in MATPA group. In the vertical plane, the perpendicular distance of the mesiobuccal cusp tip to the platal plane was found to be signicantly changed in conventional TPA group whereas no signicant change was measured in MATPA group. ConclusionMiniscrew anchored trans palatal arch offered better anchorage control of maxillary rst molar teeth in sagittal, vertical and transverse plane, during the leveling &amp; alignment stage of xed orthodontic mechanotherapy, when compared with conventional trans palatal arch.

Evidence of flexoelectricity in graphene nanobubbles created by tip induced electric field

Strain engineering in graphene nanobubbles (GNB) has made significant progress in recent years opening new possibilities to observe quantum phenomena such as Newton's ring oscillation and generation of pseudomagnetic field. Here, we demonstrated that controlled formation of graphene nanobubbles is possible on transferred graphene on standard SiO2/Si substrate by the application of external electric field through the tip of piezoelectric force microscope (PFM). We manipulated their dimensional attributes (height, area and volume) by varying tip ramp voltage and tip distance. Prominent out-of-plane piezo-response (flexoelectricity) was observed using PFM in the newly created nanobubbles due to the presence of non-uniform strain gradients in the nanobubbles. Moreover, we found quadratic dependence of the effective piezoelectric coefficient proportional to the increasing bubble creation ramp voltage. Our work motivates the exploration of flexoelectric properties and related applications with 2D nanobubbles on different substrates.

Root Resorption of Teeth Adjacent to Untreated Impacted Maxillary Canines: A CBCT Study.

Objectives The aim of this retrospective study was to determine the position of the impacted maxillary canine (IMC) and then to inspect the frequency, location, and extent of the consequent root resorption (RR) of the adjacent teeth by using CBCT. Materials and Methods Forty-one patients aged 12-68 who have 56 IMC detected on CBCT images were retrospectively examined in 3D. The canine position was determined by assessing the side of impaction, buccopalatal location, the distance of the canine cusp tip to the midline and to the occlusal plane, and canine angulation to the midline. RR of adjacent teeth was analyzed by investigating the nearest location of ectopic canine to adjacent teeth in horizontal and vertical dimensions in addition to measuring the degree of RR. Results Twenty-seven (48.2%) impacted canines were on the right side, and 29 (51.8%) were on the left. Most of these teeth 31 (55.4%) were located palatally, while buccal impaction was seen in only 13 (23.2%) canines and 12 (21.4%) were located centrally. The mean distance of the ectopic canine cusp tip to the occlusal plane was significantly higher in males (14.4 mm) than in females (10.7 mm). RR was seen in 9 central incisors (31.03%) and 21 lateral incisors (41.17%) as well as one case in the first and second premolar. This RR was slight for all the adjacent central incisors and premolars. Conclusions IMC is more frequent in females, palatally and apically. When left untreated, it may cause RR of some of the adjacent teeth with various degrees, however, with no gender preference.