Initial Curve Research Articles

On mitigating rebar–concrete interface damages due to the pre-cracking phenomena using superabsorbent polymers

This study intends to determine the effects of incorporating superabsorbent polymers (SAP) within concrete on the bond properties of steel reinforcing bars (rebar) embedded in uncracked and pre-cracked concrete. An experimental program is conducted to check the performance of SAP, as a healing agent inside the concrete, in mitigating internal damage at the rebar-concrete interface due to the pre-cracking phenomena. Two types of SAP with different particle sizes (0.15 and 0.50 mm) and chemistries are considered in the experimental program. Pull-out test results show improved bond properties of steel rebars embedded in uncracked and healed concrete containing lower dosages of SAP. However, concrete containing a high dosage of SAP shows lower bond strength, compared to normal concrete, due to the presence of macro voids. A considerable healing effect is observed for the initial bond-slip curve portion, the bond strength, and the energy absorbed by the bond mechanism, within the cracks of pre-cracked SAP-modified concrete subjected to wet-dry cycles. This study shows that SAP can significantly increase the autogenous healing performance of concrete at rebar-concrete interfacial damage sites.

Understanding the strain effect on coercivity enhancement in L10-Mn56Ga42 alloy via low-energy mechanical cryomilling

Varying degrees of strain were observed in L10-Mn56Ga42 powders via low-energy mechanical cryomilling, and the relationship between coercivity and strain was analyzed in detail. With increasing milling time, the powders do not show obvious variations in grain size and cell parameters, but a large strain is induced into the powders, leading to a remarkable enhancement in coercivity. A maximum coercivity of up to 6.7 kOe was accomplished for 20 h milled powders, with a high residual strain of about 0.96%. The initial magnetization curve indicates that the coercivity mechanism is mainly governed by the domain-wall pinning process where strain-induced defects act as pinning centers. Studies on heat treatments show that the strain-induced coercivity contributes to over 50% of the total coercivity, and a moderate annealing can eliminate the strain, changing the coercivity mechanism to a nucleation process.

On the Convergence of the Elastic Flow in the Hyperbolic Plane

AbstractWe examine the L2-gradient flow of Euler’s elastic energy for closed curves in hyperbolic space and prove convergence to the global minimizer for initial curves with elastic energy bounded by 16. We show the sharpness of this bound by constructing a class of curves whose lengths blow up in infinite time. The convergence results follow from a constrained sharp Reilly-type inequality.

Current Status of Simulation Training in Urology: A Non-Systematic Review.

Simulation has emerged as an effective solution to increasing modern constraints in surgical training. It is recognized that a larger proportion of surgical complications occur during the surgeon’s initial learning curve. The simulation takes the learning curve out of the operating theatre and facilitates training in a safe and pressure-free environment whilst focusing on patient safety. The cost of simulation is not insignificant and requires commitment in funding, human resources and logistics. It is therefore important for trainers to have evidence when selecting various simulators or devices. Our non-systematic review aims to provide a comprehensive up-to-date picture on urology simulators and the evidence for their validity. It also discusses emerging technologies and future directions. Urologists should embed evidence-based simulation in training programs to shorten learning curves while maintaining patient safety and work should be directed toward a validated and agreed curriculum.

Theoretical model of caustics method for the interfacial cracks

As a non-contact optical experimental method, caustic method is commonly employed in measuring stress intensity factor at the crack tips of different materials. Caustics theory is commonly used for solving stress intensity factor at crack tips in homogeneous isotropic materials, but it lacks the required accuracy for solving stress intensity factor in interfacial cracks in dissimilar materials. In this paper, we have deduced the theoretical equation of stress intensity factor at interfacial crack tips the orthotropic bi-materials and evaluated the effects of different crack propagation speeds, orthotropic bi-materials and other parameters on the initial curves of focal line and the shape of caustics. In addition, dynamic caustic experiments on composite/epoxy bi-materials under low velocity-impact loadings were performed and the evolution of dynamic interfacial cracks was captured by high-speed cameras which showed good agreements with theoretical results. Research results confirmed the usefulness of the application of caustic method in dissimilar isotropic and orthotropic materials, isotropic-orthotropic bi-materials and homogeneous isotropic and orthotropic materials under subsonic crack propagation velocities.

An optical method for measuring mixed-mode stress intensity factors for an arbitrarily oriented crack in cylindrical shells

This paper deals with the measurement of mixed-mode stress intensity factors for an arbitrarily oriented crack in cylindrical shells using an optical method based on a new theory of caustics. Completely analytical expressions are derived for caustic curves as well as for initial curves around the tip of an arbitrarily oriented crack in a cylindrical shell under mixed-mode conditions. The effects of mixed-mode condition, radius of curvature, shell thickness and crack angle on the caustic pattern are investigated, respectively. New procedures for the extraction of stress intensity factors KI and KII are presented using the characteristic dimensions of caustic patterns. A series of uniaxial tensile tests are performed on cylindrical shells containing an edge crack which is inclined to the axis of load by a different angle. The mixed-mode stress intensity factors obtained from the method of caustics developed here show a good agreement with previous theories and finite element results under K-dominant assumption.

A simple formula for calculating the tensile strength of brittle materials by means of the circular semi‐ring test and the optical method of caustics

The tensile strength of brittle materials is here obtained by applying the experimental method of caustics to the circular semi-ring test (CSR). In this context, first the equations of the initial and the respective caustic curves are obtained for the CSR for light reflected from the front and rear face of the CSR as well as for transmitted light, thus covering all cases for both opaque and transparent materials. It is seen that the radii of the initial curves assume complex and real values with only the latter being accepted to form the loci on the CSR to provide the caustics. Then, simple closed-form formulae are provided for determining the critical stresses at the critical points A and B on the inner and outer perimeter of the CSR, in terms of the caustics' horizontal diameter DX.

The Thioredoxin Family Proteins: Histopathological Time Course Study in the Asphyctic Male Rat Brain

Summary:Thioredoxin Family of proteins as Thioredoxin (Trxs), Glutaredoxins (Grxs) and Peroxiredoxins (Prxs) are one of the most important agents in the defense of oxidative stress and redox regulation. Perinatal asphyxia (AP) a disorder generated at the expense of the deficit of oxygen associated or not to ischemia, affects 5 to 10 of every 1,000 live births in developing country and is a serious health problem worldwide. Alterations in antioxidant protection systems are involved in the pathogenesis of hypoxic-ischemic insult and neuronal death. For these reasons it is proposed that the AP can cause changes in the distribution and expression of antioxidant proteins and enhance their deleterious or neuroprotective effects on the CNS. Methods: to determine the implication of the proteins role induced in the hypoxic brain injury, an animal model in vivo of PA was used in this work. In the first instance, the identification of the distribution of Trxs family proteins Trx1, Trx2, TrxR1, TrxR2, Txnip, Grx1, Grx2, Grx3, Grx5, γ-GCS, Prx1, Prx2, Prx3, Prx4, Prx5 and Prx6 was performed by immunohistochemistry on areas most sensitive to a hypoxia-ischemia insult: cerebellum, striatum, hippocampus, spinal cord, sustantia nigra, cortex and retina. Previous studies suggest that these proteins have an extensive and characteristic distribution in various cell types and regions of the CNS, although we observed significant differences in labeling intensity and distribution with conventional and fluorescence optical microscopy. After determining the cellular localization of Trxs, their behavior was studied by during a hypoxic- ischemic event by setting a time course at different times (2, 4, 6, 12, 24 and 72 hours post AP). Results: Trx1, Trx2, Grx1 and Grx2 proteins constitutes the main oxidoreductases in the cytosol and mitochondria, both in physiological and pathological conditions. Thus, for the short asphyxia times in which they were studied, Trx1 was detected with increased expression at 2 hours and up to 4 hours post-AP, arguing a probable neuroprotective effect, although not enough, if taken into account tissue liability and high levels of free radicals detected at initial hours and the presence of structural damage at 7 days post-AP. Trx2 shows its increase at 6 and 12 hours and Grx1 at 24 hours. For Grx2, values elicited with the ELISA technique in the initial time curve were not representative in their expression in the hippocampus, contrary to the findings in the distribution in the striatum, where Grx2 was observed to be increased. Although at 7 hours post-AP levels begin to decline, these redoxins appears to be essential in the initial response to injury. Conclusions: by demonstrating of the presence of these enzymes in different cell types and specific regions of the brain in rats subjected to AP provided us with important morphological evidence base to study later some of the molecular mechanisms involved in the pathogenesis of cerebral ischemia that will help to generate new therapeutic tools to mitigate a disease whose neurological complications have no definitive solution.

Development and validation of simplified mechanics-based capacity curves for scenario-based risk assessment of school buildings in Basel

This paper deals with the development of nonlinear static models for the calculation of capacity curves that are subsequently applied in a scenario-based assessment of school buildings. The investigated building types include unreinforced masonry buildings with rigid floors and reinforced concrete buildings with slender shear walls, both of which are typical in central Europe. The curves were established by means of simplified mechanics-based models of the structures together with the expected failure mechanisms of the structural members, from which bilinear capacity curves were calculated. These capacity curves were used to derive fragility curves for a number of predefined earthquake scenarios in Basel, Switzerland. This application revealed that with the initial capacity curves developed in this project, the damage in the earthquake scenarios was largely overestimated compared to that predicted from empirical intensity-based vulnerability models. The initial curves had been determined with models that made use of code recommendations for the assessment of existing structures together with experimental mean material characteristics. Modifications to the modelling procedure, including revised assumptions concerning the failure modes and changes to the assumed initial stiffness based on vibration measurements, led to revised curves which featured, in particular, increased ductility. With these updated and validated capacity curves, results closer to the empirical intensity-based models were obtained. While the type of modelling used herein has its limitations due to simplicity, it was still possible to account for the influence of typical characteristics (such as the detailing of RC walls) on the relative behaviour and response of the buildings, thus justifying the use of analytical capacity and fragility functions, as opposed to empirical intensity-based models, in the final risk assessment.

Alternative measure of therapy impact (TXI): Length of sojourn on treatment—Value of early restaging imaging for prediction of response to nivolumab among patients with advanced cancer.

106 Background: Cross-sectional Imaging (CI) plays an essential role in early assessment of patients on immune checkpoint inhibitors (ICIs), yet often remains inconclusive in the setting of advanced disease, prior cancer treatment, toxicity, and cancer unrelated findings. We propose a robust, reproducible imjScore based on measurable tumor response on the first two re-staging scans that may predict TXI. We are testing prognostic value of early imaging, time lag of ICIs effect, against Duration of clinically effective treatment as a Measure of Treatment Impact. Methods: Retrospective review of CI studies in 92 patients with advanced stage solid tumors treated with Nivolumab (Nivo) during 6/2015-8/2018 at BMC on standard clinical protocols. Time on therapy (TOTx) was used as a surrogate marker of therapy impact. Modified imRECIST score utilizing ∑ of 5 discrete cancer lesions at baseline, 1st, and 2nd CI since initiation of Nivolumab were adjusted for TOTx. Our imjSCORE averages "predicted days on therapy" from best fit function of tumor change/day [%] at each time point vs. TOTx and ratios between 1st and 2nd scan. Results: Median TOTx was 70 days (range 1-1029). Differences in imRECIST scores derived from two early restaging CI studies adjusted for TOTx were able to identify with high statistical significance two groups of "SHORT" vs "LONG" sojourn on Nivolumab around Median of 70 days. Early Progression curve was associated with shorter benefit of Nivo; Pseudo-progression curve showed significantly shorter sojourn on Nivolumab compared to initial Regression or Stable score curves (P < .002). Conclusions: The imjScore may differentiate with high likelihood patients with short versus long sojourn on Nivo as a novel measure of TXI. Our CI-based imjSCORE validates early imaging with a response curve and standardized analysis of the 1st and 2nd post-treatment scans. If validated with other ICIs, this scoring tool may allow early prediction of ICIs treatment response and clinical outcome. Further correlation with clinical biomarkers may lead to development of predictive nomograms of "short" versus "long" TXI.

My new normal: A patient's perspective on polymyalgia rheumatica

My new normal: A patient's perspective on polymyalgia rheumatica

GaN-Half-Bridge for Core Loss Measurements Under Rectangular AC Voltage and DC Bias of the Magnetic Flux Density

An accurate calculation of core losses is essential for the design of switched-mode power supplies. However, such predictions remain a challenge as core losses depend on various parameters, e.g., the waveform of the magnetic flux density, including its fundamental frequency and dc bias. To investigate the influence of dc bias, core loss measurements usually impose a dc current and, thus, dc bias of the magnetic field strength on ungapped toroid samples. However, hardware designers require the ac and dc excitation of the magnetic flux density. Therefore, this article proposes a half-bridge configuration to impose rectangular ac voltages on the core under test (CUT). By performing a pulsed operation in combination with an iteration method, the desired ac and dc excitation of the magnetic flux density can be obtained. GaN-HEMTs have been applied as they allow a printed circuit board design with low parasitic inductances and thus avoid ringing. The measurement setup is able to characterize magnetic materials at high frequencies for triangular magnetic flux density waveforms, including dc bias and different duty cycles. In addition, the influence of magnetic history on core losses can be studied, an issue usually not addressed in the literature. Moreover, the relationship between the dc bias of the magnetic field strength and the dc bias of the magnetic flux density is investigated. A simple functional approach, e.g., by using the initial magnetization curve, does not suffice to describe this relationship. Accordingly, core losses should be derived as a function of dc bias of the magnetic flux density for the results to be of practical use to hardware designers.

X-Model: Further Development and Possible Modifications

The main goal of the present paper is to improve the X-model used for day-ahead electricity price and volume forecasting. The key feature of the X-model is that it makes a day-ahead forecast for the entire wholesale supply and demand curves. The intersection of the predicted curves yields the forecast for equilibrium day-ahead prices and volumes. We take advantage of a technique for auction curves’ transformation to improve the original X-model. Instead of using actual wholesale supply and demand curves, we rely on transformed versions of these curves with perfectly inelastic demand. As a result, the computational requirements of our X-model are reduced and its forecasting power increases. Moreover, our X-model is more robust towards outliers present in the initial auction curves’ data.

Diagnosis and outcome analysis of diseases characterized by recurrent low-frequency sensorineural deafness

Objective:The aim of this study was to explore the clinical features, hearing prognosis and differential diagnosis of recurrent low frequency sensorineural hearing loss （RLFD） . Method:The clinical characteristics, clinical manifestations, audiological examination and auxiliary examination of RLFD patients were retrospectively analyzed. We summarized clinical features, draw the pure tone audiometry curves, and analyze the diagnosis of RLFD. Result:Forty-seven patients （53 ears） with RLFD had a hearing review time of 1-124 months. The course of disease ranged from 3 to 320 months with an average course of 29 months. ①The incidence of tinnitus in the accompanying symptoms was 93.6%（44 cases）, and the ear suffocation was 83.0%（39 cases）, 38.3% （18 cases） of the patients developed vestibular symptoms during the course of the disease. ②During the observation period, 27 cases（57.4%） were diagnosed with related diseases: 7 cases（14.9%） Meniere's disease, 6 cases（12.8%） vestibular migraine, 2 cases（4.3%） with Meniere's disease and migraine, and 1 case（2.1%） with idiopathic intracranial hypotension 11 cases（23.4%） were possible cochlear migraine; ③Migraine-related RLFD had a younger onset age, more common in women; ④83.0%（44 ears）of the affected ears had stable or improved low-frequency hearing during the observation period, 17.0%（9 ears）of the affected ears experienced low-frequency hearing; ⑤18.9%（10 ears）of the affected ears had high-frequency hearing loss; ⑥RLFD had 6 types of audiological outcomes: low-frequency improvement combined with high-frequency stability; low-frequency stability combined with high-frequency stability; low frequency progress combined with high frequency stability type; low frequency improvement combined with high frequency progress type; low frequency stability combined with high frequency progress type; low frequency progress combined with high frequency progress type; ⑦Rising type hearing curve low frequency hearing prognosis is good, mountain type and descending low frequency hearing prognosis is poor. Conclusion:Tinnitus and ear stuffiness are the early symptoms and the most disturbing symptoms in patients with RLFD. The mechanism of Migraine may play an important role in the pathogenesis of RLFD. The rare causes such as intracranial hypotension syndrome should not be ignored. Most of the patients with RLFD had stable or improved hearing after long-term fluctuation, but some patients with low or high frequency hearing might decline. The type of initial hearing curve was a prognostic factor. Long-term hearing follow-up is helpful for prognosis evaluation.

Enhanced Communication through Virtual Interdisciplinary Team Rounds for Pediatric Patients Receiving Hospice Care in Outlying Communities (FR408B)

•List three ways that virtual palliative care rounds may benefit community-based providers.•List three areas in which virtual palliative care rounds may be applied in metropolitan and rural regions. Providing hospice/palliative care (HPM) for children in the community is challenging due to limited numbers of experienced clinicians outside of medical centers. In rural areas, pediatric HPM is almost non-existent, although adult providers attempt to care for children referred to them. Telehealth has been used effectively for patient follow up. Our goal is to extend the reach of existing pediatric HPM clinicians to provide team oversight and consultation to adult organizations providing pediatric HPM care in outlying locations. Virtual Pediatric Consultative Rounds (VPCR) were developed with a large community-based adult HPM partner with nine regional offices. Each regional office typically cares for 1-5 children. A rounding sheet was developed to collate clinical information to enhance efficiency of VPCR sessions. VPCR sessions utilizing Skype for Business (HIPPAA compliant) were scheduled every other week for two hours beginning in July 2018. The hospital-based pediatric HPM team and the community-based coordinators were on-line as each nurse presented medical/psychosocial issues, medication reconciliation, code status, hospital/ED visits, follow-ups and goals. 5-10 minutes per patient was allotted including a short dialog/Q&A. Patient records were updated for both institutions and changes noted. An online survey was developed to assess the nurses' experiences with the VPCR process ranging from 1(strongly disagree) to 5 (strongly agree). Nine pediatric nurses participated in the VPCR initiative and seven completed the survey. Most nurses used a corporate cellphone for reporting; whereas, two used laptops with televideo when able. After an initial learning curve for logins, participants found the technological interface acceptable with good-to-excellent audio and video quality. –VPCR participation: (Likert 1-5) –Allowed better patient care: 3.86 –Facilitated better care coordination: 4.0 –Improved communication w/ family: 3.86 –Reduced ER visits/hospitalization: 2.57 –Enhanced dialog with referring MD: 4.29 –Improved understanding of MD's plan: 3.71 VPCR improves communication between referring hospitals and community providers, facilitates problem solving and a sense of professionalism.

Reconstruction of Velocity Distribution in Partially-Filled Pipe Based on Non-Uniform Under-Sampling

In the process of research on the flow velocity distribution in a partially filled pipe, the under-sampling of measurement data often occurs. For the first time, this problem is solved by the improved non-uniform B-spline curve fitting approximation (NBSC) method. The main innovation of this method is to reconstruct the flow velocity distribution fitting curve with a small amount of non-uniform feature points containing flow velocity information. First, the curvature of a whole discrete sampled data is analyzed, then the weighted threshold is set, and the sampled points that satisfy the threshold are extracted as the initial velocity distribution feature points. Next the node vectors were constructed according to the initial feature points, and the initial interpolation fitting curves are generated. Secondly, by using the relative deviation between the initial approximation curve and each sampled point, new feature points were added where the curve allowable deviation exceeded the specified tolerance, and then a new interpolation fitting curve was obtained. The above procedure was repeated until the fitting curve reached expected accuracy, thus the appropriate feature points were determined. Experimental results showed that, in the case of the same approximation deviation, the proposed NBSC method can solve the problem of under-sampling of measurement data better.

Magnetic Domain Analysis of Ferrite-Sintered Magnets in Thermally Demagnetized and AC Demagnetized States Using Multiple Distances Observation of MFM and Image Processing

The magnetic domain structure is an important factor in discussing the coercivity development mechanism. We have researched on the new observation method of magnetic domain structures using multiple distances observation of magnetic force microscope (MFM) and image processing. We observed magnetic domain structures in thermally demagnetized state and alternating current (ac) demagnetized state of ferrite-sintered magnets using this method. In addition, the initial magnetization curve was measured in each demagnetized state. There were differences in the domain structures and the initial magnetization curves in each demagnetized state. These differences suggest that irreversible multi-domain gains (IRMDGs) confirmed in rare-earth magnets are present even in sintered ferrite magnets.

An error-bounded B-spline curve approximation scheme using dominant points for CNC interpolation of micro-line toolpath

• The bi-chord error test fully considers the geometric properties of the micro-line toolpath. • The bi-chord errors test greatly reduces the impact of noisy points on the number and distribution of the dominant points. • The chord error estimation for the B-spline curve approximation analytically determines whether or not the geometric deviation between the polygon formed by the micro-line toolpath and the initial B-spline curve is under the chord error constraint. This paper presents a unified framework for computing a B-spline curve to approximate the micro-line toolpath within the desired fitting accuracy. First, a bi-chord error test extended from our previous work is proposed to select the dominant points that govern the overall shape of the micro-line toolpath. It fully considers the geometric characteristics of the micro-line toolpath, i.e., the curvature, the curvature variation and the torsion, appropriately determining the distribution of the dominant points. Second, an initial B-spline curve is constructed by the dominant points in the least square sense. The fitting error is unpredictable and uncontrollable. It is classified into two types: (a) the geometric deviations between the vertices of the polygon formed by the data points and the constructed B-spline curve; (b) those between the edges of the polygon and the constructed B-spline curve. Herein, an applicable dominant point insertion is employed to keep the first geometric deviation within the specified tolerance of fitting error. A geometric deviation model extended from our previous work is developed to estimate the second geometric deviation. It can be effectively integrated into global toolpath optimization. Computational results demonstrate that the bi-chord error test applies to both the planar micro-line toolpath and the spatial micro-line toolpath, and it can greatly reduce the number of the control points. Simulation and experimental results demonstrate that the proposed B-spline approximation approach can significantly improve machining efficiency while ensuring the surface quality.

Magnetic field-induced metamagnetic, magnetocaloric and pyrocurrent behaviors of Eu2CoMnO6

In this paper, the structural, transport, pyrocurrent and magnetic behaviors of Eu2CoMnO6 (ECMO) sample are reported. It was prepared by the solid-state reaction method and crystallized in monoclinic crystal structure with a space group of P21/n. A systematic study of the temperature and magnetic field-dependent susceptibility revealed a complex magnetic behavior with field-induced type-II metamagnetic phase transition of the first-order. The multiple sharp jumps in the initial magnetization curve for T < 10 K could be attributed to structural distortion related to the martensite-like strains from E*-type antiferromagnetic to ferromagnetic ordering. The metastable magnetic behavior for T ≥ 60 K is ascribed to a transformation of the low-field disordered spin glass phase to long-range ordered ferromagnetic phase, induced by critical fields. These critical fields are quite sensitive to the direction and magnitude of the field-cooling process. The temperature-dependent magnetocaloric effect with maximum value of ~3.3 J kg−1K−1 at TC ~ 123 K and the electrical transport behavior of ECMO were studied. Further, temperature dependent pyroelectric current and polarization data of ECMO are investigated.

Navigating the learning curve of spinal endoscopy as an established traditionally trained spine surgeon.

Traditionally trained spine surgeons may want to transition from open spinal surgeries to endoscopic decompressions. The aspiring endoscopic spine surgeon may have to overcome multiple hurdles to master a learning curve without readily available training. Replacing traditional time-proven open spinal surgeries with endoscopic decompression may put the surgeons' reputation at risk and have an additional negative impact on his or her practice due to reduced revenue. The authors report on the utility of the mentor- and proctorship concepts to facilitate the transition from traditional open to endoscopic outpatient spine surgeries. The study population (learning curve groups) was provided by two traditionally trained "apprentice" surgeons who have been in practice for 12 and 28 years, respectively. They trained with the remaining two authors under mentorship and proctorship arrangements. A VAS and Macnab outcomes analysis was performed by one surgeon laminectomy versus endoscopy in relationship to the case log representative of the initial learning curve. The second surgeon performed a postoperative narcotic utilization analysis as a representative way of favorable clinical outcomes in relation to his increasing case log with spinal endoscopy. The learning curve study by the first author (NA Ransom-under the proctorship program) consisted of 40 patients with 20 patients each divided into the traditional laminectomy control group and 20 patients in the endoscopic group. There were 22 females and 18 males with an average age of 57.38 years and a mean follow-up of 38.58 months. The preoperative VAS for patients in both groups was 7.95 compared to the postoperative VAS at final follow-up of 4.01 with a statistically significant postoperative VAS reduction (P<0.001) but without any significant difference between open laminectomy control- and endoscopic decompression groups. The endoscopic learning curve group outcomes improved significantly after 15 cases (P<0.048). The second author (S Gollogly-under mentorship program) performed a similar review of his surgical cases log and noted a significant reduction of postoperative narcotic utilization as a result of improved outcomes after an initial learning curve of 15 cases. Clinical outcomes for both authors showed improved Macnab outcomes in the majority of patients (NA Ransom =65%; S Gollogly =57%) with a slightly higher success rate in the laminectomy group (70%) versus the endoscopy group (65%) at a statistical significant level (P=0.036). The mentorship and proctorship approach is useful in helping traditionally trained spine surgeons to integrate spinal endoscopy into their well-established spine practices. Under the close guidance of an endoscopic master spine surgeon, the endoscopic learning curve may be comprehended by the experienced traditionally trained spine surgeon in approximately 15 lumbar decompression cases. During this initial 15-case learning curve, clinical outcomes with endoscopy may be slightly inferior to open laminectomy but may ultimately improve to equivalent levels.