Optimal angle of needle insertion for spinal anesthesia in patients with spondylolisthesis: an ultrasonographic study

Background Spondylolisthesis is a common degenerative spinal deformity. At the level of spondylolisthesis, the anatomy of the interlaminar space may differ from normal spine, in which case optimal angle of the needle insertion for spinal anesthesia may change. This study compared the optimal angle of needle insertion during spinal anesthesia in patients with and without lumbar spondylolisthesis using ultrasound. Methods We recruited 40 patients, 20 with and 20 without lumbar spondylolisthesis (group S and N, respectively). Ultrasonography was performed in the transverse midline and parasagittal oblique views at the spondylolisthesis level and the adjacent upper level. We measured the probe application angle with the longest interlaminar height of the ligamentum flavum-dura mater complex (LFD), depth from the skin to the LFD, depth from the skin to the anterior complex, and intrathecal space width. A positive angle represented a cephalad angulation. Results The optimal needle insertion angle in the transverse midline view at the spondylolisthesis level was (-) 2.7 ± 3.4° in group S and 0.8 ± 2.5° in group N (P$$<$$ < 0.001). In the parasagittal oblique view, it was (-) 2.7 ± 4.5° in group S and 1.0 ± 3.2° in group N (P = 0.004). There were no between-group differences in the angles at the upper level, with all cephalad angles in both views. Other ultrasound image data were comparable between groups. Conclusion In patients with spondylolisthesis, caudad angulation of the spinal needle can aid successful spinal puncture at spondylolisthesis level, both in the midline and paramedian approaches. Trial registration www.ClinicalTrials.gov (NCT04426916); registered 11 June 2020.

Newtons Laws Explain How Frisbees Fly

Newtonian mechanics explain the physics of how frisbees fly. Specifically, a frisbee in horizontal flight with a positive angle of attack (AOA), will fly through a static mass of air each second (‘m/) that it accelerates to a velocity (’a’) downwards, to create a downward force (Force = ma), due to Newtons 2nd law of motion. The ‘equal & opposite’ upward force generated (Newtons 3rd law of motion), provides an upward force and vertical lift. Air goes down and the frisbee goes up. It’s that simple. There are two airflows: The underside of the frisbee pushes air down. While the curved topside of the frisbee pulls air downwards due to the Coanda effect. This explanation is different to other theories of lift currently available, such as those based on fluid mechanics (Bernoulli and Navier-Stokes) and vortices. The spin on a frisbee enhances the stability of flight due to the gyroscopic effects. In turn, stability of flight allows the frisbee to generate laminar (smooth) airflows, and thus better lift. The spin itself does not directly contribute towards lift. In addition, airflow vortices account for trick throws, where the frisbee appears to defy normal physics. So what? This provides new insight into lift and flight not currently found in accepted physics textbooks. The best performing frisbee will be one that maximises the Coanda effect on the topside of the disc; to increase the amount of air displaced down. Newtons laws can explain why a frisbee thrown flat (small AOA) generates better lift and will fly further than a frisbee thrown high, on a parabolic type of path. This explanation of lift can also be applied to airplane wings.

Metastatic Squamous Cell Carcinoma of the Tonsil Mimicking Choroidal Melanoma

We describe a case of a 53-year-old man with a history of metastatic squamous cell carcinoma of the tonsil who presented with a large, dome-shaped, choroidal mass in the left eye with concern for extra-ocular extension. Standardized echography showed a choroidal mass with low-to-medium internal reflectivity, pockets of very low reflectivity, positive angle kappa, and 1+ vascularity that were concerning for primary choroidal melanoma. Biopsy of the lesion was consistent with metastatic squamous cell carcinoma of the tonsil rather than melanoma. This is only the second reported case of metastatic squamous cell carcinoma to the choroid presenting with a large vascular tumor with echographic characteristics consistent with choroidal melanoma. The unique vascularity present in some cases of squamous cell carcinoma of the tonsil may explain the vascularity and large height of this patient’s lesion. Tumor fine-needle aspiration biopsy can play an important role in patients with choroidal lesions in the setting of unusual primary tumors.

Framing gender: Representing male teachers in the Australian and New Zealand press

Over the past two decades the issue of gender imbalance in teaching has been the subject of media and political discussion. Researchers have yet to draw definitive conclusions as to the relationship between teacher gender and student achievement, but the notion that more men are needed in teaching persists, with calls for governments to enact ‘affirmative action’ policies. Despite this, surveys of male teachers have found that many believe they are portrayed negatively in the media and that they are under greater scrutiny than their female counterparts. In seeking to better understand this contradiction, this article examines 233 news stories covering the issue of men in teaching. Using framing theory, the authors found that despite a high percentage of stories carrying a positive angle, male teachers are predominantly framed in problematic ways. The authors argue that the news media is ideologically limited in its representation of male teachers, resulting in any advocacy being a counter-narrative to the prevailing logic.

Diagnostic A-Scan of Choroidal Melanoma: Automated Quantification of Parameters

Aim: To develop an automated algorithm to quantify ultrasonographic A-scan parameters of choroidal melanoma. Methods: The study included 100 consecutive patients with a clinical diagnosis of choroidal melanoma. Ultrasonographic A-scans (8 MHz, 1,550 m/s, tissue sensitivity = 67 dB) were performed by standard techniques. We created and then utilized a MATLAB® script to generate four quantifiable A-scan parameters: (1) tumor height (mm), (2) the number of internal reflectivity peaks (numerical value), (3) median internal reflectivity (%), and (4) angle κ (°). Results: There were small (≤2.5 mm, n = 32), medium (2.6–10.0 mm, n = 53), and large (> 10.0 mm, n = 14) tumors. The mean number of internal reflectivity peaks counted between the two tumor boundary spikes (surface and base) was 10.0 (σ = 8.7, range 1–37). The median value of the internal reflectivity peaks for all cases varied from 19.8 to 99.5 (mean = 68.3, σ = 20.5). A statistically significant correlation was observed between the tumor height categories and each of the three A-scan parameters: the number of internal reflectivity peaks (ρ = 0.90, p < 0.01), median internal reflectivity (ρ = –0.63, p < 0.01), and a positive angle κ (ρ = –0.32, p = 0.03). Conclusions: An automated algorithm can provide quantifiable A-scan parameters for choroidal melanoma.

Influence of Field Spacer Geometry on the Performance of a High Voltage Coaxial Type Transmission Line with Solid Dielectric Spacer in Vacuum

With the development of more powerful high power electromagnetic sources, the transmission of high voltage power particularly between pulsed power systems to huge power rated microwave sources in absence of electrical breakdown and pulse distortion has begun to become a vital issue. A high voltage coaxial type transmission line with 500 kV peak voltage in vacuum is proposed. A novel proposal of configuration bearing a positive angle of 45o with socket-type filed shaper is being discussed in this paper in a manner to improve surface flashover properties and also to decrease the distortion seen in the pulse shape. This type of transmission line provides high capability of hold off voltage. The electric field distribution of the coaxial geometry with different field shaper configurations and different spacer parameters are also investigated using COMSOL software.

Multiagent Cooperative Learning Strategies for Pursuit-Evasion Games

This study examines the pursuit-evasion problem for coordinating multiple robotic pursuers to locate and track a nonadversarial mobile evader in a dynamic environment. Two kinds of pursuit strategies are proposed, one for agents that cooperate with each other and the other for agents that operate independently. This work further employs the probabilistic theory to analyze the uncertain state information about the pursuers and the evaders and uses case-based reasoning to equip agents with memories and learning abilities. According to the concepts of assimilation and accommodation, both positive-angle and bevel-angle strategies are developed to assist agents in adapting to their environment effectively. The case study analysis uses the Recursive Porous Agent Simulation Toolkit (REPAST) to implement a multiagent system and demonstrates superior performance of the proposed approaches to the pursuit-evasion game.

HEAVENLY TEARS � EARTHLY LOSS: DIFFERENT WAYS OF COPING WITH LIFE LOSS IN TEARS IN HEAVEN, CIRCUS, AND SINCE I LOST YOU

This is a qualitative study of three pop songs rooted from the same tragic event of Eric Clapton?s son Conor who fell from the 53rd floor of his spouse?s New York apartment in March 1991. Two songs are from Clapton himself i.e. Tears in Heaven and Circus and one song from his friend Phil Collins entitled Since I Lost You. The goal of this study is to elaborate the attitude of the author through the study of formal aspects of the song such as rhyme, rhythm, tone and picth and also the metaphorical expressions in their wording. This is a library research of the three songs using a comparative technique of elaboration. The study concludes that Phil Collins as a friend who is not directly involved in the tragedy shows his sympathy through a negative and hopeless way of seeing the tragedy. He focuses more on the tragedy directly rather than the impact, psychologial process and lessons learned afterward. Eric Clapton, on the other hand, as the one who directly suffers the impact of the tragedy sees the tragic event from a more positive angle. He tries to somehow show his grief but does not want to be drifted away in this sorrow. He focuses more on the process after the tragedyby remembering the sweet moment before the tragedy (in Circus) and imagine the same sweet thing after the tragedy (in Tears in Heaven) by setting an emotional spin around the good memory and nice after life state of the child with sweet hopes and strengthening consolation

Evaluating the Effect of PCD & TialN Coated Carbide End Mill’s Rake Angle on Machinability of Titanium Alloy Ti-6Al-4V

This study evaluates the machinability of titanium alloy, Ti6Al4V in terms of tool-chip interface temperature, cutting forces and tool stresses by varying rake angle of PCD insert and compares the results with TiAlN coated carbide inserted end mill using finite element numerical simulations. It has been found that tool rake angle has significant effect and behaves differently for different evaluation parameters and also shows different behavior for two different cutting material inserts. It reduces cutting forces with every positive angle geometry, about 50% reduction is observed for both cutting tool materials for a change in angle from-7° to 34°, but for tool-chip interface temperature, 15% reduction has been observed when angle is changed from-7° to 15° but it starts rising again when angle is increased to 34° for PCD insert, but for TiAlN coated carbide insert a continuous drop of about 20% has been observed. For tool stresses tool rake angle has different effect. The stresses remains almost unchanged when angle is changed from-7° to 15° but increased by almost 20% when angle is changed to 34° for both insert materials. Results also have shown that PCD insert due to its excellent thermal conductivity and strength at elevated temperatures dissipates most of the heat into the chip and has almost half temperature near the tool edge as compared to TiAlN coated carbide insert and thus can be used for machining of Ti6Al4V alloy at much higher cutting speeds than TiAlN coated carbide insert with positive rake angle geometries (around 15°).