Knife Edge Research Articles

‘On a knife's edge’: medical, police, and legal responses to self‐harming protesters

AbstractTraditional liberal democratic theories of protest can readily account for protest violence against others or their property, and are quick to denounce and criminalize such actions. However, protests that involve self‐harm are harder to frame; they neither engage the harm principle, nor threaten a sovereign state of ostensible peace. Under liberal legalism, capacitous and consenting protesters should not have their rights of expression interfered with in such cases. However, in England and Wales, legal responses to self‐harming violence nevertheless emerge, not necessarily within a public order framework, but through a risk‐averse, medicalized lens. Co‐authored by a legal academic and a practising psychiatrist, this article argues that mental health practitioners, the police, and the courts engage in a ‘paternalistic pivot’ in self‐harming protest cases, which undermines human rights protections that are ordinarily afforded to protesters who are not causing a threat to others or their property.

Coverage hetnet based picocell and femtocell for uplink condition around building environment with single knife edge method

The development of HetNet (Heterogeneous Network) radio base stations has experienced many developments. This is indicated by the existence of microcells, macrocells, picocells, femtocells, and so on. In this research, the research is aimed at the propagation of user equipment communication systems in uplink conditions with HetNet picocells and femtocells. UE propagation is on a straight path between the building environment. The communication frequency used is 10 GHz. The communication between Tx and Rx is modeled as a diffraction mechanism, AWGN channel, and atmospheric attenuation. The Single Knife Edge (SKE) method is used to model the mechanism. The propagation channel is faced with AWGN (Additive White Gaussian Noise). The analysis of this research includes the SNR value, Adaptive Modulation and Coding (AMC) level, and percentage of communication coverage area. The AMC is based on the use of MCS (Modulation and Code Scheme). Some of the MCS modulations used QPSK, 16 QAM, and 64 QAM. As research results show that the percentage of communication coverage area obtained was gNB1 80.59 percent, gNB2 65.67%, and selection combining HetNet 95.52%.

Novel method and apparatus for evaluating knife performance in meat processing environments

Employees in food processing plants, especially in meat and fish processing facilities, often experience physical strain when using hand knives for manual tasks, leading to musculoskeletal disorders (MSDs). This global issue has prompted research into objective indicators of knife sharpness to optimize sharpening methods and assess blade quality accurately. We introduce novel metrics of hand knife sharpness and edge retention that are derived from force and torque measurements during cutting trials realized on the specifically designed experimental rig and with kinematics based on recordings of real workers. The new method and metrics provide valuable insights into blade quality, sharpening effectiveness, and edge retention, enabling comparisons among knives, steel grades, and heat treatment methods. Our study demonstrates the practical importance of these metrics for improving knife quality control processes in meat processing facilities, ultimately enhancing worker safety and operational efficiency.

'A Rose By Any Other Name': would re-branding help general practice?

Primary care is a challenging and evolving specialty. We are increasingly dealing with patients who present with complex multi-morbidities and varied constellations of symptoms that we need to masterly unravel with limited time and resources. Yet, how many times have we said or heard 'just a GP.' This study investigated the attitudes and opinions of primary care professionals towards a change in title to reflect our evolving role. We conducted a cross-sectional survey from 15 to 22 March 2022. A PubMed literature search was undertaken to formulate a questionnaire that was distributed through an online link to medical students and primary care health professionals. There were 401 medical professionals and students who participated in the survey. Overwhelmingly, 95% felt that the public perceives the professional status and qualifications of GPs as inferior to that of hospital consultants. 94% felt hospital colleagues and other health professionals perceived the professional status and qualifications of GPs as inferior to consultants. 90% would support a change in title from GP to consultant in primary care or family medicine consultant (or similar). Many felt this would reflect the evolving role of GPs. 72% felt strongly that the title change would help improve the current GP recruitment crisis. General practice is on a knife edge. Real, meaningful changes are needed to avoid a mass exodus of GPs for pastures new. Perhaps changing our title to reflect our expertise in family medicine could be one of many essential measures to improve public and professional perceptions.

Short term follow-up of femoral neck dynamic cross screw system and threaded cannulated screw in the treatment of vertically unstable femoral neck fractures

To analyze and compare the clinical effects of femoral neck dynamic cross screw system (FNS) and cannulated screws(CS) in the treatment of vertically unstable femoral neck fractures. The clinical data and short-term follow-up results of 40 patients with vertically unstable femoral neck fractures admitted from July 2020 to August 2021 were retrospectively analyzed. According to different internal fixation methods, 40 patients were divided into two groups, 20 cases in FNS group included 11 males and 9 females with a median of 58.5(50.3, 62.5) years old, and 20 in CS group included 9 males and 11 females with a median of 52.0(40.5, 58.0) years old. The operation time, knife edge length, blood loss and treatment cost of two gruops were observed and compared. The postoperative fracture healing and internal fixation were evaluated with X-ray imaging data, and the femoral neck shortening of the affected side was measured. The incidence of thigh irritation, the time of partial weight bearing and full weight bearing, early necrosis of femoral head, reoperation revision and Harris scores were compared between two groups. FNS group was followed up for 18.0(15.0, 19.0) months, CS group for 17.0(15.0, 18.8) months. There was no significant difference in operation time, incision length and blood loss between two groups(P>0.05). The cost of diagnosis and treatment in FNS group was higher than that in CS group(P<0.001). In FNS group, there was no irritation sign of the affected side thigh, while in CS group, there were 6 cases with discomfort or irritation sign of the lateral thigh(P<0.05). The average time of partial weight bearing activity in CS group was later than that in FNS group(P<0.05); However, there was no significant difference in the activity time of complete weight bearing between two groups(P=0.011>0.05). At the last follow-up, the shortened length of the affected femoral neck in CS group was greater than that in FNS group(P<0.05). There was no early necrosis of femoral head and reoperation in both groups. There was no significant difference in Harris score between two groups 12 months after operation(P>0.05). FNS treatment of vertically unstable femoral neck fractures can significantly reduce the incidence of lateral thigh irritation sign, and effectively reduce the postoperative shortening rate of vertically unstable femoral neck fractures, which can provide a relatively stable anti rotation force and anti cutting force, so that patients can go to the ground relatively early, which is conducive to the recovery of the affected hip joint function after surgery. It is a new option for the surgical treatment of vertically unstable femoral neck fractures. However, due to the high cost of treatment, In clinical practice, appropriate surgical treatment is selected according to the actual situation.

Mixing and transport of CO2 across a monolayer-covered surface in an open cylinder driven by a rotating knife edge

The dissolution of CO2 into water has attracted much attention for the modeling of air-sea gas exchange, CO2 sequestration into porous aquifers, and gas transport in bioreactors. In nearly all circumstances, the surface of water is covered by surfactants that make the gas-liquid interface behave elastically and exhibit surface (excess) shear viscosity. Here, transport and mixing of CO2 across the interface is studied in an axisymmetric system with inertia. A rotating knife edge at the interface with negligible contact surface area takes advantage of surface shear viscosity to drive a strong overturning flow in the bulk via viscous coupling. When CO2 is dissolved into water, this system has a forced convection nature that enhances the transport of CO2 into water. This transport leads to intense radial gradients in the dissolved CO2 resulting in baroclinic production of azimuthal vorticity which alters the underlying meridional flow and further enhances mixing by breaking down transport barriers. Flow visualization experiments reveal baroclinic instability and numerical simulations detail the hydrodynamics, including the effects of varying the CO2 partial pressure above the water.

Calibration of MAJIS (Moons And Jupiter Imaging Spectrometer). II. Spatial calibration.

MAJIS, Moons and Jupiter Imaging Spectrometer, is one of the scientific payloads aboard European Space Agency's Jupiter Icy Moons Explorer mission. This instrument underwent a comprehensive characterization and calibration campaign before integration on the spacecraft. In this work, we report on the measurements of the instrumental spatial responses, including the slit and pixel functions, the knife edge function, the ensquared energy, and the keystone aberration. The measurements were repeated in several positions of the field of view and within the range of MAJIS temperatures during science observations. The goal was to characterize the instrument's response under a wide set of conditions and at different visible-infrared wavelengths. The experimental setups employed to perform calibrations are described in detail, and the methodology applied to derive the instrumental spatial responses is discussed. After launch, minor changes in the instrument response and the coalignment between the two spectral channels were identified by comparing on-ground data with the first in-flight data returned by MAJIS.

Landsat 9 Thermal Infrared Sensor-2 (TIRS-2) Pre- and Post-Launch Spatial Response Performance

The launch of Landsat 9 (L9) on 27 September 2021 marks the ongoing commitment of the Landsat mission to delivering users with calibrated Earth observations for fifty years. The two imaging sensors on L9 are the Thermal Infrared Sensor-2 (TIRS-2) and the Operational Land Imager-2 (OLI-2). Shortly after launch, the image data from OLI-2 and TIRS-2 were evaluated for both radiometric and geometric quality. This paper provides a synopsis of the evaluation of the spatial response of the TIRS-2 instrument. The assessment focuses on determining the instrument’s ability to detect a perfect knife edge. The spatial response was evaluated both pre- and post-launch. Pre-launch testing was performed at NASA Goddard Space Flight Center (GSFC) under flight-like thermal vacuum (TVAC) conditions. On orbit, coastline targets were identified to evaluate the spatial response and compared against Landsat 8 (L8). The pre-launch results indicate that the spatial response of the TIRS-2 sensor is consistent with its predecessor on board L8, with no noticeable decline in image quality to compromise any TIRS science objectives. Similarly, the post-launch analysis shows no apparent degradation of the TIRS-2 focus during the launch and the initial operational timeframe.

Development of pH‐Sensitive Film for Detection of Implant Infection via Ultrasound Luminescent Chemical Imaging

AbstractA new hybrid ultrasound luminescent chemical imaging technique is described along with a pH sensor to image chemical concentrations at the surface of implanted medical devices. The purpose is to detect and study local biochemistry during infection. The sensor comprises a mechanoluminescent film (SrAl2O4:Eu, Dy microphosphors embedded in a biocompatible polymer film) and a pH indicator dye. A focused ultrasound beam generates green luminescence at the ultrasound focal point. By pulsing the ultrasound ON and OFF, the modulated luminescence can be distinguished from persistent luminescence, for high spatial resolution imaging. A red fluorescent dye and the pH indicator dye bromothymol blue are added to the coating to modulate the red‐light transmittance via pH dependent absorbance. Acidosis is observed as an increase in red luminescence intensity in spectroscopy and imaging. The films are sensitive to biologically relevant changes in pH (6.0–8.0) and can be imaged through optically scattering media to mimic tissue. The images have a knife edge spatial resolution of ≈3 mm through optically scattering phantoms, limited by the focused ultrasound spot size. This novel technique may permit the elucidation of implant infection at the implant surface and can be further developed for the measurement of other relevant chemical species in the future.

Line-edge-roughness characterization of photomask patterns and lithography-printed patterns

This paper presents the line-edge-roughness (LER) characterization of the photomask patterns and the lithography-printed patterns by enhanced knife edge interferometry (EKEI) that measures the interferometric fringe patterns occurring when the light is incident on the patterned edge. The LER is defined as a geometric deviation of a feature edge from an ideal sharp edge. The Fresnel number-based computational model was developed to simulate the fringe patterns according to the LER conditions. Based on the computational model, the photomask patterns containing LER features were designed and fabricated. Also, the patterns were printed on the glass wafer by photolithography. The interferometric fringe patterns of those two groups of patterns were measured and compared with the simulation results. By using the cross-correlation method, the LER effects on the fringe patterns were characterized. The simulation and experimental results showed good agreement. It showed that the amplitude of the fringe pattern decreases as the LER increases in both cases: photomask patterns and printed wafer patterns. As a result, the EKEI and its analysis methods showed the potential to be used in photomask design and pattern metrology, and inspection for advancing semiconductor manufacturing processes.

1879 On a knife's edge: role of a Clinical Nurse Specialist on balancing complex treatment decisions in acute surgery

Abstract Introduction 1 in 4 older individuals having emergency general surgery live with frailty, are more likely to have a longer hospital stay, readmission rate, morbidity and mortality. This underscores the importance of individualised approaches to care through Shared Decision Making (SDM). We introduced SDM into our surgical liaison service aiming to measure effectiveness and patient outcomes. Methods Between October 2021 and September 2022, patients aged &amp;gt;70 years living with frailty admitted to the surgical unit were identified by an Older Persons Clinical Nurse Specialist (CNS). Involvement in treatment decisions was measured by using the patient and clinician SDM-Q9 questionnaire. Pre-admission as well as follow-up quality of life scores at 6 months using the EQ-5D-5L (0-100) as well as Decision Regret were obtained on subsets of patients. Results Of a total of 76 patients seen by the CNS, follow-up data were available for 61 patients, clinician and patient SM-Q9 were completed in 54 patients. Clinicians were 10% more likely to strongly or completely agree that they explained choice available, 16% more likely to feel they explained treatment options compared with patients. Patients were less likely to feel completely involved in decision making. However, they were more likely to agree they understood clinical information presented them. Low levels of decision regret were ascertained at follow up where 18 patients agreed and 32 patients strongly agreed that a right decision was made of their care. Of 15 patients who underwent emergency laparotomy, mean EQ-5D scores across all domains from improved from baseline (69 vs 78). Conclusions CNS led implementation of SDM is feasible, acceptable. Patients felt involved in their care and had lower levels of decisional regret. Encouraging and investing in an environment where health professionals take time to determine what is important to their patient can be associated with better outcomes.

Ridge split assisted molar protraction

Protraction of a second molar into the gap left by a missing first molar is an option, although it is challenging to maintain root parallelism during mesial migration due to the thick and dense cortical bone. This study was carried out to make an attempt to evaluate whether molar protraction in subjects with missing mandibular first molar and knife edge ridges is possible or not using ridge split procedure (expansion).The sample consisted of 12 subjects with missing mandibular first molar and knife edge ridges. All pre-treatment records were taken, after initial leveling and alignment ridge split procedure was performed and molar protraction was carried out using mini implants. Data was collected at a fixed interval of every six weeks. Statistical analysis using Repeated-measures ANOVA and Paired t test were done for evaluation of the rate of molar protraction and mesial molar tipping 0.12mm per week and 0.9 mm per six weeks was the rate of molar protraction that was accomplished. The mean edentulous space decreased from pre protraction to third visit significantly with a p value of ≤ 0.001.There is mesial tipping of molar post protraction with a P value of 0.148 which is statistically non-significant. On an average duration for molar protraction was 8.4 months.Ridge split made molar protraction possible in subjects with missing mandibular molar and knife edge ridges and enhanced the rate of tooth movement. The absolute anterior dental anchorage for the desired orthodontic movement was achieved by utilisation of mini implants.

Effect of Ridge Splitting of Mandibular Knife Edge Ridges with Two-implant Retained Overdenture with Locator Attachments on Peri-implant Bone Level and Posterior Ridge Resorption: A One-year Preliminary Study.

This study was conducted to evaluate peri-implant bone height changes and posterior ridge resorption by using two-implant retained polyetheretherketone (PEEK) overdentures with locator attachments following expansion of mandibular knife edge ridges by ridge splitting. Eighteen patients were selected for ridge splitting followed by expansion, implant placement, and bone graft application. Six months later, the fabrication of PEEK overdentures retained by locator attachments was accomplished. Friedman test, Wilcoxon signed-rank test, and Spearman correlation were used to evaluate the changes over time. Peri-implant bone height loss increased significantly with the advance of time between 6 and 12 months following denture insertion. Posterior area index changes were significant over time when measured at the time of denture insertion and twelve months following denture insertion. The effect of using PEEK as overdenture base material retained with two locator attachments allowed sharing the load between the peri-implant bone anteriorly and residual ridge posteriorly in cases with ridge splitting technique. Using PEEK as an overdenture base material is a successful means of bone preservation. How to cite this article: Helmy MA, El-Shaheed NH, El Waseef FA, et al. Effect of Ridge Splitting of Mandibular Knife Edge Ridges with Two-implant Retained Overdenture with Locator Attachments on Peri-implant Bone Level and Posterior Ridge Resorption: A One-year Preliminary Study. J Contemp Dent Pract 2023;24(11):834-839.

Development and evaluation of the sandwich edgewise compression after impact test

A compression after impact test method has been developed to assess the damage tolerance of sandwich structures under edgewise compressive loading. This test method, recently standardized as ASTM D8287, was designed to test specimens that have been impact damaged per ASTM D7766. The fixture design utilizes end loading with top and bottom edge supports to prevent end-brooming and out-of-plane rotation. Additionally, knife edge side supports provide out-of-plane restraint to buckling, similar to the existing laminate edgewise compression after impact test fixture. The sandwich configurations investigated were constructed from glass/epoxy and carbon/epoxy facesheets with a Nomex honeycomb core. Mechanical testing was conducted to evaluate the proposed specimen design, fixturing, and test procedure. Finite element analysis was used to verify the strain gage placement and damage size limits.

STEM CELLS IN BONE REGENERATION; THE FUTURE IS NOW

The aim of the ongoing projects was to demonstrate the efficacy of autologous bone marrow derived stem cells (MSC) combined with biomaterial to induced new bone formation in a randomized multicenter controlled clinical trial.Patients with a need for bone reconstruction of residual edentulous ridges in both the mandible and maxilla due to bone defects with a vertical loss of alveolar bone volume and/or knife edge ridges (≤ than 4,5 mm) unable to provide adequate primary stabilization for dental implants were included in the clinical study. Autologous bone marrow MSC were expanded, loaded on BCP and used to augment the alveolar ridges. After five months bone biopsies were harvested at the implant position site and implants were installed in the regenerated bone. The implants were loaded after 8–12 weeks. Safety, efficacy, quality of life and success/survival were assessed. Five clinical centers, 4 different countries participated. Bone grafts harvested from the ramus of the mandibles were used as control in the projects.

“On a Knife's Edge” and Other Poems

“On a Knife's Edge” and Other Poems

Robotic Cutting of Fruits and Vegetables: Modeling the Effects of Deformation, Fracture Toughness, Knife Edge Geometry, and Motion

Robotic Cutting of Fruits and Vegetables: Modeling the Effects of Deformation, Fracture Toughness, Knife Edge Geometry, and Motion

Failure mechanism and damage tolerance of turnout point rail in high-speed railway

The failure of point rail occurred during the turnout service in the China Railway. The failure analysis was conducted using experimental and simulation methods, indicating that the combination of knife edge and stress concentration in the drive support was responsible for the crack initiation in the drive support of the point rail. Furthermore, the effects of the edge depth and location on the fatigue crack propagation of the drive support in the turnout point rail were investigated. The fatigue life for the turnout with knife edges is 10 %–20 % of that without knife edges. The crack propagation rate on the point rail drive support increased sharply with the increase of the edge depth. The crack propagation rate also increased with edge proximity to stress concentration point. Meanwhile, the damage tolerance of the point rail was defined based on the result that the fatigue life before the crack size 10 mm accounted for 84.4 % of the whole fatigue life.

The Effect of Different Finish Line Designs and Material Types on the Periodontal Response of Single Crown Restoration: A 3-year Follow-up Study

Purpose: Different restorative materials and marginal finish lines may contribute to periodontal inflammation, in spite of patients' proper oral hygiene habits. The aim of this study was to evaluate the effect of different finish line designs and restorative materials on periodontal health. Materials and Methods: In this retrospective clinical study, the periodontal clinical parameters of 450 crown restorations fabricated with different finish line designs (chamfer, shoulder, knife-edge) and different materials (Metal-ceramic, Zirconia, Glass-ceramic) were evaluated at baseline and at 12th, 24th and 36th months after the cementation. The data were analyzed with Repeated Measures ANOVA and post hoc least significant difference tests were performed (α=.05). Results: Periodontal clinical parameters significantly increased during the 36-month follow-up period. The marginal finish line and material type had no significant effect on the probing depth and gingival index scores. The highest plaque index scores were observed in zirconia restorations with knife edge finish lines at the 36th month after crown placement. Conclusions: The periodontal health of the prepared tooth was negatively affected by the increased follow-up duration regardless of the marginal finish line design and material type. The clinicians should consider the favorable effect of the glass-ceramic crown restorations with a chamfer finish line on the plaque control for long-term success.

Chiral knife edge: A simplified rattleback to illustrate spin inversion.

We present the chiral knife edge rattleback, an alternative version of previously presented systems that exhibit spin inversion. We offer a full treatment of the model using qualitative arguments, analytical solutions as well as numerical results. We treat a reduced, one-mode problem which not only contains the essence of the physics of spin inversion, but that also exhibits an unexpected connection to the Chaplygin sleigh, providing insight into the nonholonomic structure of the problem. We also present exact results for the full problem together with estimates of the time between inversions that agree with previous results in the literature.