Synthetic Reconstructions Research Articles

Predictive coding compressive sensing optical coherence tomography hardware implementation

Compressed sensing (CS) is an approach that enables comprehensive imaging by reducing both imaging time and data density, and is a theory that enables undersampling far below the Nyquist sampling rate and guarantees high-accuracy image recovery. Prior efforts in the literature have focused on demonstrations of synthetic undersampling and reconstructions enabled by compressed sensing. In this paper, we demonstrate the first physical, hardware-based sub-Nyquist sampling with a galvanometer-based OCT system with subsequent reconstruction enabled by compressed sensing. Acquired images of a variety of samples, with volume scanning time reduced by 89% (12.5% compression rate), were successfully reconstructed with relative error (RE) of less than 20% and mean square error (MSE) of around 1%.

Prospects of Detecting a Jet in Sagittarius A* with Very-long-baseline Interferometry

Event Horizon Telescope (EHT) images of the horizon-scale emission around the Galactic center supermassive black hole Sagittarius A* (Sgr A*) favor accretion flow models with a jet component. However, this jet has not been conclusively detected. Using the “best-bet” models of Sgr A* from the EHT Collaboration, we assess whether this nondetection is expected for current facilities and explore the prospects of detecting a jet with very-long-baseline interferometry (VLBI) at four frequencies: 86, 115, 230, and 345 GHz. We produce synthetic image reconstructions for current and next-generation VLBI arrays at these frequencies that include the effects of interstellar scattering, optical depth, and time variability. We find that no existing VLBI arrays are expected to detect the jet in these best-bet models, consistent with observations to date. We show that next-generation VLBI arrays at 86 and 115 GHz—in particular, the EHT after upgrades through the ngEHT program and the ngVLA—successfully capture the jet in our tests due to improvements in instrument sensitivity and (u, v) coverage at spatial scales critical to jet detection. These results highlight the potential of enhanced VLBI capabilities in the coming decade to reveal the crucial properties of Sgr A* and its interaction with the Galactic center environment.

Design and development of the magnetic diagnostic systems for the first operational phase of the SMART tokamak.

A set of magnetic diagnostics has been designed, manufactured, and calibrated for the first operational phase of the small aspect ratio tokamak. The sensor suite comprises of Rogowski coils; 2D magnetic probes; and poloidal, saddle, and diamagnetic flux loops. A set of continuous Rogowski coils has been manufactured for the measurement of plasma current and induced eddy currents in conductive elements. A set of flux loops and magnetic probes will be used as input for the reconstruction of the magnetohydrodynamic equilibrium. The quantity and position of these sensors have been verified to be sufficient with synthetic equilibrium reconstructions using the equilibrium fitting code and baseline scenarios computed with the Fiesta code. These sensors will also be used as input for the real-time control system, and magnetic probes will be used for the detection of plasma instabilities. The calibration procedure for the magnetic probes is described, and the results are shown. The signal conditioning and data acquisition systems are described.

Synthetic and practical reconstructions of SST and seawater pH using the novel multiproxy SMITE method.

Geochemical proxies of sea surface temperature (SST) and seawater pH (pHsw) in scleractinian coral skeletons are valuable tools for reconstructing tropical climate variability. However, most coral skeletal SST and pHsw proxies are univariate methods that are limited in their capacity to circumvent non-climate-related variability. Here we present a novel multivariate method for reconstructing SST and pHsw from the geochemistry of coral skeletons. Our Scleractinian Multivariate Isotope and Trace Element (SMITE) method optimizes reconstruction skill by leveraging the covariance across an array of coral elemental and isotopic data with SST and pHsw. First, using a synthetic proxy experiment, we find that SMITE SST reconstruction statistics (correlation, accuracy, and precision) are insensitive to noise and variable calibration period lengths relative to Sr/Ca. While SMITE pHsw reconstruction statistics remain relative to δ11B throughout the same synthetic experiment, the magnitude of the long-term trend in pHsw is progressively lost under conditions of moderate-to-high analytical uncertainty. Next, we apply the SMITE method to an array of seven coral-based geochemical variables (B/Ca, δ11B, Li/Ca, Mg/Ca, Sr/Ca, U/Ca & Li/Mg) measured from two Bermudan Porites astreoides corals. Despite a <3.5 year calibration period, SMITE SST and pHsw estimates exhibit significantly better accuracy, precision, and correlation with their respective climate targets than the best single- and dual-proxy estimators. Furthermore, SMITE model parameters are highly reproducible between the two coral cores, indicating great potential for fossil applications (when preservation is high). The results shown here indicate that the SMITE method can outperform the most common coral-based SST and pHsw reconstructions methods to date, particularly in datasets with a large variety of geochemical variables. We therefore provide a list of recommendations and procedures for users to begin implementing the SMITE method as well as an open-source software package to facilitate dissemination of the SMITE method.

A multipurpose, adolescent idiopathic scoliosis-specific, short MRI protocol: A feasibility study in volunteers

IntroductionVisualization of scoliosis typically requires ionizing radiation (radiography and CT) to visualize bony anatomy. MRI is often additionally performed to screen for neural axis abnormalities. We propose a 14-minutes radiation-free scoliosis-specific MRI protocol, which combines MRI and MRI-based synthetic CT images to visualize soft and osseous structures in one examination. We assess the ability of the protocol to visualize landmarks needed to detect 3D patho-anatomical changes, screen for neural axis abnormalities, and perform surgical planning and navigation. Methods18 adult volunteers were scanned on 1.5 T MR-scanner using 3D T2-weighted and synthetic CT sequences. A predefined checklist of relevant landmarks was used for the parameter assessment by three readers. Parameters included Cobb angles, rotation, torsion, segmental height, area and centroids of Nucleus Pulposus and Intervertebral Disc. Precision, reliability and agreement between the readers measurements were evaluated. Results91 % of Likert-based questions scored ≥ 4, indicating moderate to high confidence. Precision of 3D dot positioning was 1.0 mm. Precision of angle measurement was 0.6° (ICC 0.98). Precision of vertebral and IVD height measurements was 0.4 mm (ICC 0.99). Precision of area measurement for NP was 8 mm2 (ICC 0.55) and for IVD 18 mm2 (ICC 0.62) for IVD. Precision of centroid measurement for NP was 1.3 mm (ICC 0.88–0.92) and for IVD 1.1 mm (ICC 0.88–91). ConclusionsThe proposed MRI protocol with synthetic CT reconstructions, has high precision, reliability and agreement between the readers for multiple scoliosis-specific measurements. It can be used to study scoliosis etiopathogenesis and to assess 3D spinal morphology.

Biologic versus synthetic prosthesis for chest wall reconstruction: a matched analysis.

The aim of this study was to compare postoperative outcomes between biologic and synthetic reconstructions after chest wall resection in a matched cohort. All patients who underwent reconstruction after full-thickness chest wall resection from 2000 to 2022 were reviewed and stratified by prosthesis type (biologic or synthetic). Biologic prostheses were of biologic origin or were fully absorbable and incorporable. Integer matching was performed to reduce confounding. The study end point was surgical site complications requiring reoperation. Multivariable analysis was performed to identify associated risk factors. In total, 438 patients underwent prosthetic chest wall reconstruction (unmatched: biologic, n = 49; synthetic, n = 389; matched: biologic, n = 46; synthetic, n = 46). After matching, the median (interquartile range) defect size was 83 cm2 (50-142) for the biologic group and 90 cm2 (48-146) for the synthetic group (P = 0.97). Myocutaneous flaps were used in 33% of biologic reconstructions (n = 15) and 33% of synthetic reconstructions (n = 15) in the matched cohort (P = 0.99). The incidence of surgical site complications requiring reoperation was not significantly different between biologic and synthetic reconstructions in the unmatched (3 [6%] vs 29 [7%]; P = 0.99) and matched (2 [4%] vs 4 [9%]; P = 0.68) cohorts. On the multivariable analysis, operative time [adjusted odds ratio (aOR) = 1.01, 95% confidence interval (CI), 1.00-1.01; P = 0.006] and operative blood loss (aOR = 1.00, 95% CI, 1.00-1.00]; P = 0.012) were associated with higher rates of surgical site complications requiring reoperation; microvascular free flaps (aOR = 0.03, 95% CI, 0.00-0.42; P = 0.024) were associated with lower rates. The incidence of surgical site complications requiring reoperation was not significantly different between biologic and synthetic prostheses in chest wall reconstructions.

Dual-Probe Transcranial Full-Waveform Inversion: A Brain Phantom Feasibility Study.

Despite being a low-cost, portable and safe medical imaging technique, transcranial ultrasound imaging is not used widely in adults because of the severe degradation and distortion of signals caused by the skull. Full-waveform inversion (FWI) has recently been found to have potential as an effective method for transcranial ultrasound tomography to obtain high-quality, subwavelength-resolution acoustic models of the brain using low-frequency ultrasound data. In this study is the first demonstration of this method in recovering a high-resolution 2-D reconstruction of a brain and skull ultrasound imaging phantom using experimentally acquired data. A 2:5 scale brain phantom encased within a 3-D-printed skull-mimicking layer was created to simulate a clinical transcranial imaging target. To obtain tomographic ultrasound data on the brain and skull phantom, a tomographic ultrasound acquisition system was designed and implemented using commercially available low-frequency cardiac probes. FWI reconstructions of the brain and skull phantom were performed using the acquired tomographic data and were compared with corresponding synthetic reconstructions. This comparison was used to evaluate the feasibility of the proposed imaging system when employing different transducer array configurations. We demonstrate the successful FWI reconstruction of the brain phantom within the skull mimic from experimentally acquired tomographic ultrasound data. To mitigate the effects of the skull-mimicking material, a reflection-matching algorithm was applied to model the morphology of the skull layer prior to performing the inversion. The findings of this study provide a promising step toward the clinical use of FWI for transcranial ultrasound imaging in adults.

Allograft or Synthetic Mesh Extensor Mechanism Reconstruction After TKA Carries a High Risk of Infection, Revision, and Extensor Lag.

Extensor mechanism disruption is a devastating complication after TKA. Extensor mechanism reconstruction can be performed using an allograft or synthetic mesh. Recent studies have disagreed about the durability of these reconstructions. Evaluating a larger series of reconstructions that use current popular techniques and principles provides information to guide patient and surgeon expectations while bringing to light the potential fate of patients who experience an infection postoperatively. (1) What was the 5-year survival free of repeat revision surgery or persistent extensor lag of more than 30° after allograft or synthetic mesh reconstruction of extensor mechanism disruptions after TKA, and did this differ between techniques? (2) What was the 5-year survival free of infection after allograft or mesh reconstruction, and what proportion of those patients experienced a secondary severe complication (arthrodesis or amputation)? Between April 2008 and December 2020, 123 patients underwent extensor mechanism reconstruction after TKA at one center. Of those, 37% (45) were lost to follow-up before 2 years, had not been seen in the past 5 years, did not reach a study endpoint (repeat revision or extensor lag > 30°) before that time, or underwent primary repair and thus could not be analyzed, leaving 63% (78) for analysis here. During the study period, we considered extensor mechanism surgery when acute or chronic disruption of the patellar or quadriceps tendon was present or there was a fracture of the patella resulting in extensor lag. The decision to use either mesh or an allograft largely depended on surgeon experience and familiarity with either technique. We collected patient demographics, operative details (location of disruption and presence of a hinged prosthesis), subsequent periprosthetic joint infection (PJI), and postoperative SF-12 and Knee Injury and Osteoarthritis Outcome Score, Joint Replacement, scores. We used Kaplan-Meier survivorship analysis, with endpoints of extensor lag more than 30° or revision of the reconstruction and PJI. The mean follow-up duration was 5.3 ± 3.2 years. Survivorship free from revision or recurrent extensor lag was 54% (95% CI 44% to 66%) at 5 years. There was no difference between those undergoing reconstruction with allografts and those with mesh in terms of survivorship free from those endpoints at that timepoint (52% [95% CI 40% to 68%] versus 57% [95 CI% 41 to 78%]; p = 0.99). Survivorship free from PJI was 81% (95% CI 73% to 90%) at 2 years. There was no difference between those with allografts and those with mesh in terms of survivorship free from PJI at that timepoint (79% [95% CI 69% to 92%] versus 83% [95% CI 71% to 98%]; p = 0.75). Of the 17 patients who experienced PJI, four ultimately underwent arthrodesis and three more underwent transfemoral amputation. Allograft and synthetic mesh reconstructions commonly left patients with persistent limb dysfunction, while several patients had PJI and some underwent salvage procedures. Although improvements have been made with regard to treating extensor mechanism disruptions, patients and surgeons should be well aware of the potential adverse outcomes when determining management and use these findings to conduct risk-benefit analyses. There is a need for future studies to identify protocols that improve the durability of reconstructions and to determine whether interventions such as prolonged prophylactic antibiotic therapy have a role in minimizing the risk of PJI. Level III, therapeutic study.

Automatic and standardized quality assurance of digital mammography and tomosynthesis with deep convolutional neural networks

ObjectivesThe aim of this study was to develop and validate a commercially available AI platform for the automatic determination of image quality in mammography and tomosynthesis considering a standardized set of features.Materials and methodsIn this retrospective study, 11,733 mammograms and synthetic 2D reconstructions from tomosynthesis of 4200 patients from two institutions were analyzed by assessing the presence of seven features which impact image quality in regard to breast positioning. Deep learning was applied to train five dCNN models on features detecting the presence of anatomical landmarks and three dCNN models for localization features. The validity of models was assessed by the calculation of the mean squared error in a test dataset and was compared to the reading by experienced radiologists.ResultsAccuracies of the dCNN models ranged between 93.0% for the nipple visualization and 98.5% for the depiction of the pectoralis muscle in the CC view. Calculations based on regression models allow for precise measurements of distances and angles of breast positioning on mammograms and synthetic 2D reconstructions from tomosynthesis. All models showed almost perfect agreement compared to human reading with Cohen’s kappa scores above 0.9.ConclusionsAn AI-based quality assessment system using a dCNN allows for precise, consistent and observer-independent rating of digital mammography and synthetic 2D reconstructions from tomosynthesis. Automation and standardization of quality assessment enable real-time feedback to technicians and radiologists that shall reduce a number of inadequate examinations according to PGMI (Perfect, Good, Moderate, Inadequate) criteria, reduce a number of recalls and provide a dependable training platform for inexperienced technicians.

Pelvic ring reconstruction with tibial allograft, screws and rods following enneking type I and IV resection of primary bone tumors

IntroductionSurgery of primary malignant tumors involving the sacroiliac joint requires wide resection, which often interrupts the pelvic ring. Nowadays, restoration of the pelvic ring to provide stability and which technique is most fitting remain subject to debate. The aim of this study is to evaluate the results of pelvic reconstruction with pedicle screw instrumentation and tibial allograft following Enneking Type I-IV resections. Patients and methodsAll patients who underwent reconstruction with tibial allograft, screws and rods after resection of areas I and IV for primary bone tumors between 2017 and 2022 were reviewed. Clinical and radiological characteristics, fusion rate and functional results were analyzed. The MSTS score and the TESS were used to evaluate functional results. ResultsSeven patients were included in the study. Chondrosarcoma was the most common histology. Only four patients reported pain. No fractures were observed at tumor diagnosis. Computer-assisted navigation was used in six cases. Reconstruction was performed in four cases with a screw inserted in the homolateral L5 pedicle and in the ischium, in two cases with a screw in the homolateral L4 pedicle and another in the homolateral L5 pedicle, in the last case with two screws inserted in L4 and L5, one screw in the ischium and another one in the residual iliac wing. In this case a contralateral stabilization was also carried out. The spine screws and the iliac screws were connected with a rod. The mean follow-up for all 7 patients was 37 months. One patient (16.6%) died due to general complications not directly related to the surgery; while the others are alive and apparently free of disease. Complete fusion was obtained in four out of seven patients and the average time for fusion was 9 months. The average MSTS score and TESS were 58.7% and 57.8%, respectively. DiscussionThe need for reconstruction is thoroughly debated in literature. The advantages of restoring posterior pelvis stability are the prevention of long-term pain associated with limb shortening and secondary scoliosis. Re-establishment of the pelvic ring can be achieved through synthetic, biologic or hybrid reconstructions. ConclusionsMore studies that assess the surgical consequences at long-term follow-up and help clarify the indications for reconstruction and the specific technique are necessary to confirm our preliminary results.

Diagnostic accuracy of automated ACR BI-RADS breast density classification using deep convolutional neural networks

ObjectivesHigh breast density is a well-known risk factor for breast cancer. This study aimed to develop and adapt two (MLO, CC) deep convolutional neural networks (DCNN) for automatic breast density classification on synthetic 2D tomosynthesis reconstructions.MethodsIn total, 4605 synthetic 2D images (1665 patients, age: 57 ± 37 years) were labeled according to the ACR (American College of Radiology) density (A-D). Two DCNNs with 11 convolutional layers and 3 fully connected layers each, were trained with 70% of the data, whereas 20% was used for validation. The remaining 10% were used as a separate test dataset with 460 images (380 patients). All mammograms in the test dataset were read blinded by two radiologists (reader 1 with two and reader 2 with 11 years of dedicated mammographic experience in breast imaging), and the consensus was formed as the reference standard. The inter- and intra-reader reliabilities were assessed by calculating Cohen’s kappa coefficients, and diagnostic accuracy measures of automated classification were evaluated.ResultsThe two models for MLO and CC projections had a mean sensitivity of 80.4% (95%-CI 72.2–86.9), a specificity of 89.3% (95%-CI 85.4–92.3), and an accuracy of 89.6% (95%-CI 88.1–90.9) in the differentiation between ACR A/B and ACR C/D. DCNN versus human and inter-reader agreement were both “substantial” (Cohen’s kappa: 0.61 versus 0.63).ConclusionThe DCNN allows accurate, standardized, and observer-independent classification of breast density based on the ACR BI-RADS system.Key Points• A DCNN performs on par with human experts in breast density assessment for synthetic 2D tomosynthesis reconstructions.• The proposed technique may be useful for accurate, standardized, and observer-independent breast density evaluation of tomosynthesis.

ACL Replacement with Synthetic vs. Biological Tendon Grafts: Long-Term Follow-Up Comparison Using Objective Evaluations

Background and Aim of the Study: Anterior cruciate ligament (ACL) tears are among the most common articular injuries in sports and can be responsible for knee instability and reduced articular performance. Treatment can be either conservative or operative, and ligament reconstruction may be carried out using biological autologous grafts or synthetic materials. Several studies have sought to evaluate and compare functional results in treated patients. However, there is still very limited information available on long-term follow-up and clinical outcomes are generally evaluated only using subjective scores. In this study, we assessed long-term functional and biomechanical results in patients treated with biologic and synthetic ligaments using objective measures. Materials and Methods: Patients were divided according to whether ACL reconstruction was biologic or synthetic. The Tegner activity scale was used before and after surgery. Post-operative subjective scores such as the IKDC Questionnaire and the Tegner-Lysholm score were also recorded. The Y Balance Test was used to assess global stability and mobility of the lower limb. Kinematic Rapid Assessment (KiRA) was used to evidence and estimate ligamentous laxity during the Pivot Shift and Lachman tests. Results: Clinical subjective patient and operator-dependent scores as well as objective biomechanical findings were similar and comparable in patients treated with biologic and synthetic reconstructions after more than 10 years of use. Conclusions: Both synthetic and biological tendon grafts may represent good reconstructive approaches to treat torn ACLs, and remain effective even for a long period of time if implanted in suitable target patients.

Biologic and synthetic ligament reconstructions achieve better functional scores compared to osteosynthesis in the treatment of acute acromioclavicular joint dislocation.

To systematically review the outcomes of surgical treatments of acute acromioclavicular joint dislocation. Studies were identified by electronic databases (Ovid, PubMed). All studies reporting functional and radiological outcomes of surgical treatments of acute acromioclavicular joint dislocations were included. Following data were extracted: authors and year, study design, level of evidence, number of patients, age, classification of acromioclavicular joint dislocation, time to surgery, surgical technique, follow-up, clinical and imaging outcomes, complications, and failures. Descriptive statistics was used, when a data pooling was not possible. Comparable outcomes were pooled to generate summary outcomes reported as frequency-weighted values. Quality appraisal was assessed through the MINORS checklist. One hundred and thirty-three studies were included for a total of 4473 shoulders. Mean age of participants was 36.9years. Mean follow-up was 42.06months. Arthroscopy showed better ASES (p < 0.0001) and lower VAS pain score (p = 0.0249) compared to an open approach. Biologic and synthetic reconstructions demonstrated better results over osteosynthesis techniques. Biologic techniques showed overall better Constant (p = 0.0001) and DASH (p = 0.0215) scores, while synthetic reconstruction showed better UCLA score (p = 0.0001). Among suture buttons, triple button showed overall better results in Constant (p = 0.0001) and VAS (p = 0.0001) scores, while better results in DASH score (p = 0.0003) were achieved by 2 double button techniques. Overall, the level of evidence was low. Biological and synthetic reconstructions achieved better functional scores compared to osteosynthesis. Among suture buttons, the triple button showed better functional performance. IV.

Anatomic reconstruction of the acromioclavicular joint provides the best functional outcomes in the treatment of chronic instability.

To systematically review the outcomes of surgical treatments of chronic acromioclavicular joint dislocation. Studies were identified by electronic databases (Ovid, PubMed). All studies reporting functional and radiological outcomes of surgical treatments of chronic acromioclavicular joint dislocations were included. Following data were extracted: authors and year, study design, level of evidence, number of patients, age, classification of acromioclavicular joint dislocation, time to surgery, surgical technique, follow-up, clinical and imaging outcomes, complications and failures. Descriptive statistics was used, when a data pooling was not possible. Comparable outcomes were pooled to generate summary outcomes reported as frequency-weighted values. Quality appraisal was assessed through the MINORS checklist. Fourty-four studies were included for a total of 1020 shoulders. Mean age of participants was 38years. Mean follow-up was 32.9months. Arthroscopic techniques showed better results than open approach (p < 0.0001). Synthetic reconstructions demonstrated better functional outcomes compared to internal fixation and biologic techniques (p < 0.0001). Among biologic techniques, combined coracoclavicular and acromioclavicular ligaments reconstruction showed better Constant (p = 0.0270) and ASES (p = 0.0113) scores compared to isolated coracoclavicular ligaments reconstruction; anatomic biologic non-augmented graft reconstruction showed better Constant (p < 0.0001), VAS (p < 0.0001) and SSV (p = 0.0177) results compared to augmented techniques. No differences in functional outcomes could be found between anatomic biologic non-augmented graft versus synthetic reconstructions. Overall, methodological quality of the included studies was low. Anatomic reconstructions, both synthetic and biologic, showed the best functional results. IV.

How Much Do Underestimated Field Strengths from Zeeman–Doppler Imaging Affect Spin-down Torque Estimates?

Abstract Numerous attempts to estimate the rate at which low-mass stars lose angular momentum over their lifetimes fill the literature. One approach is to use magnetic maps derived from Zeeman–Doppler imaging (ZDI) in conjunction with so-called “braking laws.” The use of ZDI maps has advantages over other methods because it allows information about the magnetic field geometry to be incorporated into the estimate. However, ZDI is known to underestimate photospheric field strengths due to flux cancellation effects. Recently, Lehmann et al. conducted synthetic ZDI reconstructions on a set of flux transport simulations to help quantify the amount by which ZDI underestimates the field strengths of relatively slowly rotating and weak activity solar-like stars. In this paper, we evaluate how underestimated angular momentum loss rate estimates based on ZDI maps may be. We find that they are relatively accurate for stars with strong magnetic fields but may be underestimated by a factor of up to ∼10 for stars with weak magnetic fields. Additionally, we re-evaluate our previous work that used ZDI maps to study the relative contributions of different magnetic field modes to angular momentum loss. We previously found that the dipole component dominates spin-down for most low-mass stars. This conclusion still holds true even in light of the work of Lehmann et al.

Beyond natural: synthetic expansions of botanical form and function.

SummaryPowered by developments that enabled genome‐scale investigations, systems biology emerged as a field aiming to understand how phenotypes emerge from network functions. These advances fuelled a new engineering discipline focussed on synthetic reconstructions of complex biological systems with the goal of predictable rational design and control. Initially, progress in the nascent field of synthetic biology was slow due to the ad hoc nature of molecular biology methods such as cloning. The application of engineering principles such as standardisation, together with several key technical advances, enabled a revolution in the speed and accuracy of genetic manipulation. Combined with mathematical and statistical modelling, this has improved the predictability of engineering biological systems of which nonlinearity and stochasticity are intrinsic features leading to remarkable achievements in biotechnology as well as novel insights into biological function. In the past decade, there has been slow but steady progress in establishing foundations for synthetic biology in plant systems. Recently, this has enabled model‐informed rational design to be successfully applied to the engineering of plant gene regulation and metabolism. Synthetic biology is now poised to transform the potential of plant biotechnology. However, reaching full potential will require conscious adjustments to the skillsets and mind sets of plant scientists.

Early Outcomes of Pes Planus Reconstruction Using Either Hamstring Allograft or Synthetic Ligament

Category:Hindfoot, Midfoot/ForefootIntroduction/Purpose:Maintenance of the medial longitudinal arch is crucial to efficient kinematics in gait. It is supported by as complex interplay of osseous structures, ligaments, extrinsic tendons and plantar fascia.Two ligaments critical to stabilising the medial longitudinal arch are the Spring (Calcaneofibular) and Naviculocuneiform ligaments. The Spring Ligament serves as a sling within the “Acetabulum Pedis” to orientate the Talus relative to the Calcaneus and Navicular. The Naviculocuneiform ligament is an important plantar tension band and a separate entity to the Posterior Tibial Tendon (PTT) insertion. Attenuation of these ligaments leads to Pes Planus deformity and subsequent defunctioning of the PTT. This study evaluates the functional and radiological outcomes of Spring and Naviculocuneiform ligament reconstruction using Hamstring (Semitendinosis) Allograft and Synthetic ligament (Internal BraceTM, Arthrex).Methods:33 consecutive Pes Planus reconstructions were performed between 11/11/2013 and 06/03/2018. All patients were followed up prospectively with serial radiographs and functional scores including; MOXFQ, EQF5D and VAS. Minimum follow up was six months.At the midpoint during the study there was transition to using Synthetic Ligament instead of allograft. This was due to availability and ease of use.Surgical technique for both reconstructions included a proximal medial gastrocnemius recession and medialising calcaneal osteotomy. For allograft reconstructions, a pre-tensioned Semitendinosis allograft was fixed proximally to Talar neck using a tenodesis screw and passed plantar to PTT and through a bone tunnel in the medial cuneiform. Synthetic ligaments were inserted from the Sustentaculum Tali to the medial cuneiform in a hammock fashion. In both reconstructions tendinopathic PTTs were excised and a Flexor Digitorum Longus transfer used.Results:There were 17 synthetic ligament reconstructions (6 male, 11 female) and 16 allograft reconstructions (6 male, 10 female). Groups were matched pre-operatively for age, functional scores and radiological markers (T test P values >0.05).At six months significantly better improvements were observed in the synthetic ligament group compared to allograft group with regards to VAS, MOXFQ pain score, Meary’s line, 1st metatarsal Talus angle, Talonavicular uncoverage angle and Hindfoot alignment (T test P < 0.05).Statistical significance was maintained at 12 months with the synthetic ligament providing a significantly better reduction of Meary’s line 1st Metatarsal Talar angle, Talonavicular uncoverage and hindfoot alignment. 2 patients were revised to double fusions in the allograft group and 1 patient revised in the synthetic ligament group.Conclusion:Statistically significant improved functional scores and radiological appearance can be found up to 1 year following Synthetic ligament reconstruction of the Spring and Naviculocuneiform ligaments when compared to Hamstring allograft.

Comparison of statistical inversion with iteratively regularized Gauss Newton method for image reconstruction in electrical impedance tomography

In this paper, we investigate image reconstruction from the Electrical Impedance Tomography (EIT) problem using a statistical inversion method based on Bayes’ theorem and an Iteratively Regularized Gauss Newton (IRGN) method. We compare the traditional IRGN method with a new Pilot Adaptive Metropolis algorithm that (i) enforces smoothing constraints and (ii) incorporates a sparse prior. The statistical algorithm reduces the reconstruction error in terms of ℓ2 and ℓ1 norm in comparison to the IRGN method for the synthetic EIT reconstructions presented here. However, there is a trade-off between the reduced computational cost of the deterministic method and the higher resolution of the statistical algorithm. We bridge the gap between these two approaches by using the IRGN method to provide a more informed initial guess to the statistical algorithm. Our coupling procedure improves convergence speed and image resolvability of the proposed statistical algorithm.

Phase imaging and synthetic aperture super-resolution via total internal reflection microscopy.

Total internal reflection microscopy is mainly used in its fluorescence mode and is the reference technique to image fluorescent proteins in the vicinity of cell membranes. Here, we show that this technique can easily become a phase microscope by simply detecting the coherent signal resulting from the interference between the field scattered by the probed sample and the total internal reflection. Moreover, combining several illumination angles permits generating synthetic aperture reconstructions with improved resolutions compared to standard label-free microscopy techniques.

Interspecific Cross-Attraction between the South American Cerambycid Beetles Cotyclytus curvatus and Megacyllene acuta is Averted by Minor Pheromone Components.

During field screening trials conducted in Brazil in 2015, adults of both sexes of the cerambycid beetles Cotyclytus curvatus (Germar) and Megacyllene acuta (Germar) (subfamily Cerambycinae, tribe Clytini) were significantly attracted to racemic 3-hydroxyhexan-2-one and racemic 2-methylbutan-1-ol, chemicals which previously have been identified as male-produced aggregation-sex pheromones of a number of cerambycid species endemic to other continents. Subsequent analyses of samples of beetle-produced volatiles revealed that males of C. curvatus sex-specifically produce only (R)-3-hydroxyhexan-2-one, whereas males of M. acuta produce the same compound along with lesser amounts of (2S,3S)-2,3-hexanediol and (S)-2-methylbutan-1-ol. Follow-up field trials showed that both sexes of both species were attracted to synthetic reconstructions of their respective pheromones, confirming that males produce aggregation-sex pheromones. The minor pheromone components of M. acuta, (S)-2-methylbutan-1-ol and (2S,3S)-2,3-hexanediol, synergized attraction of that species, but antagonized attraction of C. curvatus to (R)-3-hydroxyhexan-2-one. Beetles of othercerambycine species also were attracted in significant numbers, including Chrysoprasis linearis Bates, Cotyclytus dorsalis (Laporte & Gory), and Megacyllene falsa (Chevrolat). Our results provide further evidence that 3-hydroxyhexan-2-one is a major component of attractant pheromones of numerous cerambycine species world-wide. Our results also highlight our increasing understanding of the crucial role of minor pheromone components in imparting species specificity to cerambycid pheromone blends, as is known to occur in numerous species in other insect families.