Optimal Alignment Research Articles

Design of an all hollow fiber‐coupled middle infrared laser heterodyne radiometer (LHR)

AbstractAn integrated optics method, using hollow fibers which easily ensures optimal beam alignment of the local oscillator (LO) and incoherent solar radiation and promotes high photomixing efficiency, is proposed for a compact, rugged, and high‐efficiency all hollow fiber‐coupled photomixing assembly in the mid‐infrared (IR). The method is adopted for the design of an all‐hollow fiber‐coupled mid‐IR laser heterodyne radiometer (LHR) using an 8 µm external‐cavity quantum cascade laser as LO. Coupling efficiency, attenuation coefficients, total‐loss transmission, and output beam divergence of the HE11 mode in hollow fibers for the all hollow fiber‐coupled mid‐IR LHR are discussed in detail and are shown to highly depend on the launch conditions. Meanwhile, the selection of input and output coupling lenses that are associated with the hollow fibers is also studied for achieving the theoretical loss of the HE1m mode in hollow fibers and high heterodyne performance. It shows that using a hollow fiber for photomixing supersedes conventional spatially separated optics.

Improving MRI Access: A framework for optimizing MRI scheduling templates

Introduction/backgroundWithin radiology departments, alignment of available imaging capacity with demand across different patient groups helps ensure that all patient populations are receiving timely and equitable care. The objective of the MRI Schedule Optimization project was to implement a 5-step framework to review and update the current MRI schedule templates at the Joint Department of Medical Imaging (JDMI) to ensure optimal alignment with demand across patient populations. MethodsThe project, governed by clinical and clerical stakeholders and operational leadership (Owners), followed a 5-step process: (1) Analysis of baseline data related to MRI demand and current schedule composition (2) Current state assessment of MRI operations via interviews and observations (3) Updating of schedules to align with demand (4) Review of process improvement opportunities (5) Go-live planning and evaluation. ResultsCurrent state analysis revealed that misalignment of the original schedule with demand was as high as 11% for some divisions. Updated MRI schedules were implemented with a maximum variance from demand of 3%. The updated schedules also allocated 27 additional inpatient slots to respond to inpatient demand. In addition, several process improvement opportunities were identified and implemented to streamline scheduling processes, day of exam workflows and inpatient workflow management. Discussion/conclusionThe MRI Schedule Optimization project followed a structured framework to comprehensively review and realign the MRI schedules at JDMI to the needs of our patient population by improving access and identifying process improvement opportunities. This scheduling framework can be applied to perform similar schedule update exercises at any radiology department.

Design and operation of transfer lines for plasma wakefield accelerators using numerical optimizers

The Advanced Wakefield (AWAKE) Experiment is a proof-of-principle experiment demonstrating the acceleration of electron beams via proton-driven plasma wakefield acceleration. AWAKE Run 2 aims to build on the results of Run 1 by achieving higher energies with an improved beam quality. As part of the upgrade to Run 2, the existing proton and electron beamlines will be adapted and a second plasma cell and new 150-MeV electron beamline will be added. The specification for this new 150-MeV beamline will be challenging as it will be required to inject electron bunches with micron-level beam size and stability into the second plasma cell while being subject to tight spatial constraints. In this paper, we describe the techniques used (e.g., numerical optimizers and genetic algorithms) to produce the design of this electron line. We present a comparison of the methods used in this paper with other optimization algorithms commonly used within accelerator physics. Operational techniques are also studied including steering and alignment methods utilizing numerical optimizers and beam measurement techniques employing neural networks. We compare the performance of algorithms for online optimization and beam-based alignment in terms of their efficiency and effectiveness.

Immediate Effects of the Reverse Plank Exercise on Muscle Thickness and Postural Angle in Individuals with the Forward Shoulder Posture.

The forward shoulder posture (FSP) results from shoulders being pulled forward by shortened anterior shoulder girdle muscles. The objective of this study was to investigate the short-term effectiveness of the reverse plank exercise on parascapular muscle thickness and forward shoulder angle (FSA) in patients with FSP. Participants were divided into the FSP and non-FSP (NFSP) groups based on the observed angle between the horizontal line of the C7 spinous process and the acromion process. All participants performed a total of five sets of reverse plank exercises at 30 s per set. FSA and muscle thickness of the pectoralis major (PM), serratus anterior (SA), upper trapezius (UT), and lower trapezius (LT) were measured before and after the reverse plank exercise. The muscle thicknesses of the SA and LT, and the FSA, were significantly increased after exercise in the FSP group (p < 0.05). Muscle thickness of the PM and UT significantly decreased after the exercise. In the NFSP group, muscle thickness of the LT was significantly increased, and muscle thickness of the PM and UT were significantly reduced after exercise (p < 0.05). Upon using between-group analysis, there were significant differences between the FSA, SA, UT, and LT groups (p < 0.05). The reverse plank exercise has the short-term benefit of correcting and preventing FSP by increasing SA and LT thickness while decreasing PM and UT thickness. We believe that the reverse plank exercise significantly improved the ability to prevent FSP in FSP-related muscles and was beneficial in achieving optimal postural alignment.

PHYLOGENETIC ANALYSIS OF THE LUNGWORMS (NEMATODA: METASTRONGYLOIDEA) INFERRED USING NUCLEAR RIBOSOMAL AND MITOCHONDRIAL DNA SEQUENCES.

Phylogenetic relationships among the mammal-parasitic lungworms (Metastrongyloidea) were inferred using small- and large-subunit ribosomal DNA sequences together with 12S ribosomal mtDNA sequences. Maximum parsimony and Bayesian inference methods were used from optimal alignments and those filtered for alignment ambiguity. Analysis of 30 ingroup sequences using ribosomal DNA sequences yielded a single most parsimonious tree. Monophyly of the Metastrongyloidea was supported, but there was no support for monophyly of any of the 7 families as they have been traditionally defined. Parafilaroides decorus, an abursate lungworm of pinnipeds currently classified in the Filaroididae, was nested within a clade containing members of the Pseudaliidae, parasites of cetaceans. The tree also shows clades somewhat resembling the traditional familial divisions of the Metastrongyloidea, but in all groups, paraphyletic relationships were recovered. In a combined analysis of nuclear rDNA and 12S mtDNA, maximum parsimony and Bayesian analyses showed similar patterns to those observed with only nuclear rDNA sequences. Based on the phylogeny, the respiratory tract was inferred to be the ancestral predilection site for Metastrongyloidea, with multiple evolutionary invasions of extrapulmonary sites such as sinuses, circulatory system, and meninges. Similarly, the ancestral host was inferred to be a carnivore with subsequent colonization events into marsupial, rodent, artiodactyl, pinniped, and cetacean hosts.

Comparison of 3 Positioning Techniques for Fractionated High-precision Radiotherapy in an Orthotopic Mouse Model of Pancreatic Cancer.

Small-animal irradiators are widely used in oncologic research, and many experiments use mice to mimic radiation treatments in humans. To improve fractionated high-precision irradiation in mice with orthotopic pancreatic tumors, we evaluated 3 positioning methods: no positioning aid, skin marker, and immobilization devices (immobilization masks). We retrospectively evaluated the translation vector needed for optimal tumor alignment (by shifting the mouse in left-right, in cranio-caudal, and in anterior-posterior direction) on cone-beam CT from our small-animal radiotherapy system. Of the 3 methods, the skin marker method yielded the smallest mean translation vector (3.8 mm) and was the most precise method overall for most of the mice. In addition, the skin marker method required supplemental rotation (that is, roll, pitch, and yaw) for optimal tumor alignment only half as often as positioning without a positioning aid. Finally, the skin marker method had the highest scores for the quality of the fusion results. Overall, we preferred the skin marker method over the other 2 positioning methods with regard to optimal treatment planning and radiotherapy in an orthotopic mouse model of pancreatic cancer.

Optimal array alignment to deliver high performance in flexible conducting polymer‐based thermoelectric devices

• High charge mobility and optimal oxidation level leads to high power factor;. • Identification of the optimal distance between two adjacent TE arrays for devices;. • A flexible thermoelectric device shows a power density of 1.21 µW∙cm −2 . Flexible thermoelectric devices (F-TEDs) show great potentials to be applied in curved surface for power generation by harvesting low-grade energy from human body and other heat sources. However, their power generation efficiency is constrained by both unsatisfactory constituent materials performance and immature device design. Here, we used an optimal alignment of vertically-aligned poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) arrays to assemble a 2.7 × 3.2 cm 2 F-TEDs, exhibiting a maximum power output of 10.5 µW. Such a high performance can be ascribed to the outstanding power factor of 198 µW m −1 K −2 by the synergetic effect of both high charge mobility and optimal oxidation level and the optimized array alignment that maximizes the temperature difference utilization ratio across the TE legs. Particularly, optimized leg distance of 6 mm and leg length of 12 mm are determined to realize a high temperature difference utilization ratio of over 95% and a record-high output power density of 1.21 µW cm −2 under a temperature difference of 30 K. Further, reliable bending (1000 cycles) and stability (240 h) tests indicate the outstanding mechanical robustness and environmental stability of the developed F-TEDs. This study indicates our reasonable device design concept and facile material treatment techniques secure high-performance F-TEDs, serving as a reference for other flexible energy harvesting devices with wide practical applications.

The Cochlea in Branchio-Oto-Renal Syndrome: An Objective Method for the Diagnosis of Offset Cochlear Turns.

An "unwound" or "offset" cochlea has been described as a characteristic imaging feature in patients with branchio-oto-renal syndrome, and recently recognized to be associated in particular to those with EYA1 gene mutations. Determination of this feature has traditionally relied on subjective visual assessment. Our aim was to establish an objective assessment method for cochlear offset (the cochlear turn alignment ratio) and determine an optimal cutoff turn alignment ratio value that separates individuals with EYA1-branchio-oto-renal syndrome from those with SIX1-branchio-oto-renal syndrome and healthy controls. Temporal bone CT or MR imaging from 40 individuals with branchio-oto-renal syndrome and 40 controls was retrospectively reviewed. Cochlear offset was determined visually by 2 independent blinded readers and then quantitatively via a standardized technique yielding the cochlear turn alignment ratio. The turn alignment ratio values were compared between cochleae qualitatively assessed as "not offset" and "offset." Receiver operating characteristic analysis was used to determine the ability of the turn alignment ratio to differentiate between these populations and an optimal cutoff turn alignment ratio value. Cochlear offset and turn alignment ratio values were analyzed for each branchio-oto-renal syndrome genotype subpopulation and for controls. The turn alignment ratio can accurately differentiate between cochleae with and without an offset (P < .001). The optimal cutoff value separating these populations was 0.476 (sensitivity = 1, specificity = 0.986, J = 0.986). All except 1 cochlea among the EYA1-branchio-oto-renal syndrome subset and all with unknown genotype branchio-oto-renal syndrome had a cochlear offset and a turn alignment ratio of <0.476. All except 1 cochlea among the SIX1-branchio-oto-renal syndrome subset and all controls had no offset and a turn alignment ratio of >0.476. There is a statistically significant difference in turn alignment ratios between offset and nonoffset cochleae, with an optimal cutoff of 0.476. This cutoff value allows excellent separation of EYA1-branchio-oto-renal syndrome from SIX1-branchio-oto-renal syndrome and from individuals without branchio-oto-renal syndrome or sensorineural hearing loss. The turn alignment ratio is a reliable and objective metric that can aid in the imaging evaluation of branchio-oto-renal syndrome.

Research on Urban Greenway Alignment Selection Based on Multisource Data

At present, people’s growing need for a beautiful ecological environment needs to be met. As a high-quality ecological product, greenways help improve the living environment and promote green and coordinated development. How to scientifically and rationally plan greenway routes and expand the green ecological network has become an important issue for the sustainable development of high-density built-up areas. Therefore, this study determines the suitability evaluation system of urban greenway alignment selection based on spatial constructiveness, greenway accessibility, resource attractiveness and public demand through factor analysis. Taking Xixi Wetland to South Lake in Yuhang District as an example, combining urban multi-source data and GIS spatial analysis methods, all routes suitable for greenway construction in the study area were determined, and four excellent greenway routes were initially identified through manual correction. Subsequently, the PSO-BP neural network model was trained using 172 greenway samples to obtain a greenway alignment suitability evaluation model with an accuracy of more than 96%, which was used for subsequent greenway alignment optimization. The above four preliminary greenway routes are substituted into the PSO-BP model to obtain the optimal greenway routes in the study area. The results show that there are 17 indicators in 4 levels and 8 dimensions in the urban greenway route selection potential model, among which two indicators, public cycling and running demand, have a greater weight and should be highly considered in the route selection assessment. The optimal planned route for the greenway start from Guangfu Temple entrance of Xixi Wetland, follow the roadside green belt and Yuhangtang River greenway to South Lake. The study obtained the best planning route for the greenway from Xixi Wetland to South Lake in Yuhang District, which is a new practice of landscape garden planning and design supported by multisource data and new technologies, with a view to providing a reference for the preferential selection of urban greenway routes in similar high-density built-up areas.

Construction of Computer Algorithms in Bioinformatics of the Fusion Genetic Algorithm

With the continuous in-depth exploration of life sciences, bioinformatics based on life sciences, computer algorithms, and statistics have gradually developed. The research of bioinformatics mainly focuses on the study of genes, and the structural characteristics of genes lead to a large amount of extremely complex data in the study of bioinformatics. Analyzing data in bioinformatics research requires accurate calculation by computer algorithms. However, common computer algorithms such as the dynamic programming algorithm and the genetic algorithm have the disadvantages of large memory or inaccurate optimization. Combining the ant colony algorithm (ACA) and GA can give the advantages of the two methods that should be fully utilized to efficiently analyze the biological information data. In this paper, the ant colony fusion genetic algorithm (ACA-GA), GA, and dynamic programming algorithm are used to compare and analyze the sensitivity, convergence speed, sequence alignment accuracy, and required memory space of gene sequences. The experimental results show that compared with ACA-GA, the dynamic programming algorithm has the advantage of finding the optimal alignment of 100%, but the memory required is too large, the memory required is more than 10 times that of the ant colony fusion genetic algorithm and the sensitivity is not as good as ACA-GA. The convergence speed of ACA-GA is faster than the gene comparison speed of GA and the accuracy is 2.6% better than that of GA on average. ACA-GA has the advantages of GA and ACA, which can improve the computational efficiency of biological data in bioinformatics.

Vertical alignment optimization of mountain railways with terrain‐driven greedy algorithm improved by Monte Carlo tree search

AbstractVertical alignment design is an important process for railway construction which fundamentally affects the infrastructure investment cost. Determining an optimized vertical alignment is a challenging task since the objective function is non‐linear, non‐differentiable, and quite unsmooth. Great efforts have been invested in solving the vertical alignment optimization problem and many methods have been proposed. However, for vertical alignment designs in complex mountainous regions, the terrain conditions impose great difficulties and, hence, many bridges and tunnels are generally required. Thus, reasonably locating bridges and tunnels along the entire alignment (EA) is a major concern that deserves further investigations. To solve this problem, this study develops a terrain‐driven greedy algorithm improved by Monte Carlo tree search (T‐GRA‐MCTS). A terrain‐driven method is proposed to determine the number and longitudinal distribution of vertical points of intersection (VPIs). In order to trade off the local section of an alignment versus the EA when optimizing each VPI along the alignment to locate bridges and tunnels reasonably, an MCTS is employed and integrated with a GRA. The basic MCTS is modified for vertical alignment optimization with a novel equation for computing the upper confidence bounds for trees and a customized termination criterion is provided. A real‐world railway case is used to demonstrate the effectiveness of the proposed method. The results show that the T‐GRA‐MCTS performs better than a greedy search method without MCTS or a widely used nature‐inspired algorithm (i.e., a particle swarm optimization). Moreover, it can find a less expensive solution than the one designed by experienced human engineers.

Level selection for optimal adult spinal deformity correction: A narrative review

Adult spine deformity (ASD) is the loss of the normal sagittal and coronal alignment necessary to maintain the head over the hips. ASD increases energy expenditure to maintain normal balance and horizontal gaze, and can lead to chronic pain, fatigue, and significant functional disability. Selection of upper and lower instrumented levels for ASD constructs is critical to achieving and maintaining an optimal post-operative alignment. While classifications and recommendations have improved level selection strategies, decision-making still remains largely dependent on the individual surgeon. This work summarizes available literature on level selection for ASD constructs.

Optimal immediate sagittal alignment for kyphosis in ankylosing spondylitis following corrective osteotomy.

PurposeTo investigate the optimal immediate sagittal alignment of kyphosis in ankylosing spondylitis (AS) following corrective osteotomy.MethodsSeventy-seven AS patients who underwent osteotomy were enrolled. Radiographic parameters, including global kyphosis (GK), lumbar lordosis (LL), T1 spinopelvic inclination (T1SPI), sagittal vertical axis (SVA), T1 pelvic angle (TPA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and PI and LL mismatch (PI–LL), were collected. The clinical outcome was evaluated using the Scoliosis Research Society-22 (SRS-22) questionnaire and Oswestry Disability Index (ODI). At the final follow-up, SVA > 5 cm was regarded as sagittal imbalance, and a total ODI ≤ 20 or total SRS-22 score ≥4 was considered to indicate a good clinical outcome.ResultsSeventy-seven patients with an average age of 37.4 ± 8.6 years were followed up for 29.4 ± 4.2 months. At the final follow-up, GK, LL, PT, SS, TPA, and T1SPI showed some degree of correction loss (P < 0.05). The follow-up parameters could be predicted with the immediate postoperative parameters through their linear regression equation (P < 0.05). The postoperative immediate T1SPI, TPA, SVA, and PI were also highly correlated with the clinical outcome (ODI and/or SRS-22) at the final follow-up (P < 0.05). Based on the relationship, the optimal immediate sagittal alignment for obtaining good clinical outcome was determined: T1SPI ≤ 0.9°, TPA ≤ 31.5°, and SVA ≤ 9.3cm. AS patients with PI ≤ 49.2° were more likely to achieve the optimal alignment and obtained lower ODI and a lower incidence of sagittal imbalance than those with PI > 49.2° at the final follow-up (P < 0.05).ConclusionPostoperative immediate parameters could be used to predict the final follow-up parameters and clinical outcome. The optimal postoperative immediate sagittal alignment of AS patients was T1SPI ≤ 0.9°, TPA ≤ 31.5°, and SVA ≤ 9.3 cm, providing a reference for kyphosis correction and a means for clinical outcome evaluation. Patients with a lower PI (≤49.2°) were more likely to achieve optimal alignment and obtain satisfactory clinical outcomes.

Promoting remanufacturing through subsidy and environment tax: Channel co-opetition, incentive alignment and regulation optimization

Recently, many governments have levied environment tax on production while subsidizing the output of remanufactured components to promote resource-saving and pollution reduction. Considering government’s regulations, this paper investigates whether the supplier selling remanufactured components (Supplier R) should develop a self-brand and whether the original equipment manufacturer (OEM) should keep sourcing from this competitive Supplier R or source from a supplier selling new components (Supplier N). We develop a channel system comprising of Supplier R, Supplier N, and OEM, based on which we analyze their equilibrium decisions in three typical structures (i.e., Base Scenario, Co-opetitive Scenario, Chain-to-chain Scenario). We find the OEM prefers to purchase remanufactured components when (1) its brand image advantage is significant; or (2) its brand image advantage is limited but the environment tax rate is high; or (3) its brand image advantage is limited, the environment tax rate is low, but the subsidy to supplier is high, even if Supplier R has self-brand and competes with the OEM. Our results are both theoretically interesting and practically relevant because we build a unifying model to study the government’s regulation optimization and show a full map for both the component suppliers and the OEMs to decide market encroachment or channel structure configuration.

Railway Alignment Optimization Considering Lifecycle Costs

The problem of railway alignment optimization is studied, with particular attention given to computing lifecycle costs while considering train speed profile optimization and traffic demand. Recurring expenses, including energy, user, and maintenance costs, are considered in the lifecycle. A novel speed profile optimization method for the energy-efficient operation of trains is developed and incorporated in a simulation model, which considers regenerative braking energy. According to the train motion simulation results, the energy consumption and travel time per round trip are obtained, based on which the recurring costs are computed by taking traffic demand into account. The horizontal and vertical alignments are jointly optimized with the train speed profile based on the computed recurring and initial expenses, which include rolling stock, earthwork, bridge, tunnel, right-of-way, and length-dependent construction costs. A case study and sensitivity analyses are presented to discuss the impacts of traffic demand on the optimized railway alignment. The effectiveness of the speed profile optimization method is demonstrated by comparing its simulated results with those without speed control.

High-precision Sr and Nd isotope measurements using a dynamic zoom lens-equipped thermal ionisation mass spectrometer

Techniques for the determination of radiogenic strontium (87Sr/86Sr) and neodymium (143Nd/144Nd) isotope ratios by Thermal Ionisation Mass Spectrometry (TIMS) are presented in this study. We have developed a 5 lines acquisition routine for both elements, taking advantage of the 16 Faraday cups available on the Nu Instruments TIMS in conjunction with an efficient zoom lens system. This allows increased flexibility regarding the number of lines in a multidynamic acquisition routine whilst maintaining optimal peak alignment and peak shape for every measurement line despite the fact that the detectors are not movable. The long-term reproducibility obtained for our Sr (NBS 987) and Nd (Rennes-Ames) standard solutions gives a (87Sr/86Sr)multidyn of 0.7102467 ± 0.0000043 (6.0 ppm, 2 s.d., n = 38) and a (143Nd/144Nd)multidyn of 0.5119537 ± 0.0000022 (4.2 ppm, 2 s.d., n = 31), respectively. We also report (87Sr/86Sr)multidyn and (143Nd/144Nd)multidyn for a set of terrestrial rock standards (including 5 basalts (BCR-2, BHVO-2, BIR-1, Be-N and BR-24), one rhyolite (RGM-1) and one andesite (AGV-2)) with the same, or greater, level of precision as for the pure standards solutions. This level of precision is 2 to 3 times better than the literature data for Sr isotope ratios, and comparable to the latest high precision data reported for Nd isotope ratios. This is the first paper reporting such high precisions for radiogenic Sr and Nd data generated using a TIMS from Nu Instruments. Significant statementHigh precision Sr and Nd isotopic measurements are of key importance in the field of Earth Sciences because they are powerful tools to trace sources of materials and to date them. Here, we report the first high-precision data for 87Sr/86Sr and 143Nd/144Nd (external error of 5–6 ppm for Sr and 4–5 ppm for Nd) measured using a Nu Instruments TIMS. Such precisions will open new opportunities in fields such as geochemistry, geochronology, cosmochemistry, archaeology or forensics.

Optimization of metro vertical alignment for minimized construction costs and traction energy: A dynamic programming approach

Vertical alignment significantly affects the construction costs and train traction energy use of a metro system. Existing studies on this subject mostly optimized the vertical alignment while considering train traction energy consumption or construction costs only. There is still a lack of efficient approach for the vertical alignment optimization problem which considers both construction costs and traction energy consumption. To this end, this paper proposes a two-stage optimization program involving both the design of metro vertical alignment and train speed profile, with the objective of minimizing the total costs of construction and train traction energy. An iterative approach is proposed for solving the two-stage program, in which a dynamic programming (DP) algorithm with a backward search method is designed to seek an optimal vertical alignment given an energy-efficient train speed profile. The model and algorithm approach are tested on real-world case studies on the Line 14 of Guangzhou Metro in China. The results show that compared with the existing heuristic algorithms, the DP approach performs better in computation time and solution quality. Moreover, the optimized vertical alignments outperform that designed by experienced designers in terms of total costs of construction and traction energy consumption, with an average savings rate of 6.0%.

P100. Are we focused on the wrong early postoperative quality metrics? Optimal realignment outweighs perioperative risk in adult spinal deformity surgery

BACKGROUND CONTEXT While reimbursement is centered on 90-day outcomes, some patients persevere through these short-term, transient complications and manage to still achieve optimal, long-term outcomes. PURPOSE Assess whether achieving optimal alignment suffering similar perioperative complications compared to suboptimally-aligned peers are inhibited from reaching long-term clinical success and better cost-utility. STUDY DESIGN/SETTING Retrospective cohort study of a prospective adult spinal deformity (ASD) database. PATIENT SAMPLE A total of 1,541 patients. OUTCOME MEASURES Cost-per-QALY, radiographic realignment, clinical outcomes. METHODS Operative ASD pts with 2Y data were included. Optimal radiographic outcome was defined by SRS-Schwab low deformity in PI-LL, matched in T1PA and being aligned in PI-based PT at 6 weeks. After stratifying pts based on meeting optimal outcome, multivariate analysis controlling for baseline demographics was used to determine significance for complications and hospital-acquired conditions (HACs; DVT/PE, UTI, deep/superficial infection). Calculated Cost per QALY for each time point by 2Y. RESULTS There were 917 ASD pts included. Regarding approach, 69% posterior approach, 31% combined. Groups: 131 were "optimal" (O) and 786 were "not optimal" (NO). Means comparison tests revealed significant differences in age, BMI, but not gender or frailty. The NO group had fewer osteotomies and a lower Invasiveness Index. Analysis of perioperative complications showed that the O group suffered equivocal perioperative complications (58.0% vs 52.2% in the NO group; p=.173) and rates of HACs (9.0% vs. 8.9%, p=.810). Analysis of long-term complications showed that patients in the NO group suffered more major neurological (p=.015) and major mechanical complications (p=.025), and more reoperations (28.7% vs 19.9%; p=.037). When controlling for baseline deformity, age, BMI and frailty, Optimal Outcome patients more often met Best Clinical Outcome (21.5% vs. 11.7%, p=.002). Cost-utility adjusted analysis with determined no difference in the two groups by 6 weeks and 6 months. However, the O group generated significantly better cost-utility by one year, which maintained lower Costs per QALY (p=.005) at two years in favor of the O group. CONCLUSIONS Despite incurring equivocal perioperative complications, patients who met our optimal outcome criteria experienced significantly less mechanical complications and reoperations by 2 years, leading to a better long-term cost-utility overall. Accordingly, a higher, transient perioperative complication profile should not preclude surgical correction and future policy efforts should place more consideration on the long-term for outcome measures in adult spinal deformity surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. While reimbursement is centered on 90-day outcomes, some patients persevere through these short-term, transient complications and manage to still achieve optimal, long-term outcomes. Assess whether achieving optimal alignment suffering similar perioperative complications compared to suboptimally-aligned peers are inhibited from reaching long-term clinical success and better cost-utility. Retrospective cohort study of a prospective adult spinal deformity (ASD) database. A total of 1,541 patients. Cost-per-QALY, radiographic realignment, clinical outcomes. Operative ASD pts with 2Y data were included. Optimal radiographic outcome was defined by SRS-Schwab low deformity in PI-LL, matched in T1PA and being aligned in PI-based PT at 6 weeks. After stratifying pts based on meeting optimal outcome, multivariate analysis controlling for baseline demographics was used to determine significance for complications and hospital-acquired conditions (HACs; DVT/PE, UTI, deep/superficial infection). Calculated Cost per QALY for each time point by 2Y. There were 917 ASD pts included. Regarding approach, 69% posterior approach, 31% combined. Groups: 131 were "optimal" (O) and 786 were "not optimal" (NO). Means comparison tests revealed significant differences in age, BMI, but not gender or frailty. The NO group had fewer osteotomies and a lower Invasiveness Index. Analysis of perioperative complications showed that the O group suffered equivocal perioperative complications (58.0% vs 52.2% in the NO group; p=.173) and rates of HACs (9.0% vs. 8.9%, p=.810). Analysis of long-term complications showed that patients in the NO group suffered more major neurological (p=.015) and major mechanical complications (p=.025), and more reoperations (28.7% vs 19.9%; p=.037). When controlling for baseline deformity, age, BMI and frailty, Optimal Outcome patients more often met Best Clinical Outcome (21.5% vs. 11.7%, p=.002). Cost-utility adjusted analysis with determined no difference in the two groups by 6 weeks and 6 months. However, the O group generated significantly better cost-utility by one year, which maintained lower Costs per QALY (p=.005) at two years in favor of the O group. Despite incurring equivocal perioperative complications, patients who met our optimal outcome criteria experienced significantly less mechanical complications and reoperations by 2 years, leading to a better long-term cost-utility overall. Accordingly, a higher, transient perioperative complication profile should not preclude surgical correction and future policy efforts should place more consideration on the long-term for outcome measures in adult spinal deformity surgery.

144. Prophylactic proximal junctional measures improves cost efficacy of adult spinal deformity surgery, with optimal cost utility seen in those with concurrent optimal realignment

144. Prophylactic proximal junctional measures improves cost efficacy of adult spinal deformity surgery, with optimal cost utility seen in those with concurrent optimal realignment

Correlations between alignment gaps and nucleotide substitution or amino acid replacement

To assess the conventional treatment in evolutionary inference of alignment gaps as missing data, we propose a simple nonparametric test of the null hypothesis that the locations of alignment gaps are independent of the nucleotide substitution or amino acid replacement process. When we apply the test to 1,390 protein alignments that are informed by protein tertiary structure and use a 5% significance level, the null hypothesis of independence between amino acid replacement and gap location is rejected for ∼65% of datasets. Via simulations that include substitution and insertion-deletion, we show that the test performs well with true alignments. When we simulate according to the null hypothesis and then apply the test to optimal alignments that are inferred by each of four widely used software packages, the null hypothesis is rejected too frequently. Via further simulations and analyses, we show that the overly frequent rejections of the null hypothesis are not solely due to weaknesses of widely used software for finding optimal alignments. Instead, our evidence suggests that optimal alignments are unrepresentative of true alignments and that biased evolutionary inferences may result from relying upon individual optimal alignments.