Sufficient Clearance Research Articles

A split-belt instrumented treadmill with uneven terrain

The biomechanics of walking are far less understood for uneven terrain than flat or even surfaces. This is due in part to a lack of ground reaction force and moment recordings from each leg. These are often obtained with split-belt instrumented treadmills, which are currently incompatible with uneven terrain, making it difficult to perform biomechanics analyses such as inverse dynamics. Here we show how a standard split-belt instrumented treadmill (Bertec, Inc., Columbus, OH) can be modified to accommodate a variety of uneven terrains. The principal design considerations are structural clearance to allow passage of an uneven treadmill belt and fabrication of the terrain. We designed mechanical components with sufficient clearance for terrains up to 0.045 m high, and formed the terrain from uneven strips of polystyrene. Measured ground reaction forces from each leg at typical walking speeds agreed well with an intact benchmark treadmill (minimum interclass cross correlation score = 0.97). The modifications had negligible effect on the treadmill’s structural strength. The terrain produced some noise-like vibrations, but at much higher frequencies than fundamental to human locomotion. The uneven terrain treadmill can record many steps of the full complement of ground reaction forces and moments from individual legs.

Beyond viability: Advancing CHO cell culture process strategies to modulate host cell protein levels

Chinese Hamster Ovary (CHO) cells are widely utilized in bioprocessing industry for monoclonal antibody (mAb) production. In many instances, challenges persist in achieving sufficient clearance of Host Cell Proteins (HCPs) in the final drug substance. While purification strategies usually offer substantial HCP clearance, certain "problematic" HCPs, particularly lipases, continue to pose significant challenges. This study investigates the accumulation of various "problematic" HCPs in CHO cell culture using transcriptomics, revealing correations between cell culture parameters and HCP level. Contrary to conventional assumptions, viability alone does not reliably predict HCP levels, with factors such as clone selection, host cell line choice, media and feed compositions significantly influencing HCP accumulation. Leveraging transcriptomics-based approaches, we demonstrate the potential of upstream process control strategies to mitigate HCP presence and improve biologic product quality. Our findings underscore the importance of considering diverse cell culture parameters in bioprocess optimization to ensure product stability and quality. While promising, further research is needed to elucidate the mechanisms underlying HCP release and propagation through downstream processing stages, emphasizing the necessity of a comprehensive integrated approach to HCP control in biologics production.

Characterization of multi-rotor aircraft using truss support structure

Characterization of multi-rotor drone aircraft noise is vital to expanded use within the United States. To provide compatibility with current propagation and perception models, acoustic noise characterization focuses on the creation of equivalent lower hemispheres, and application of methods developed for manned aircraft for description of the noise directivity patterns. But a previous measurement determined that a refinement of these methods was required for the application to drone noise. One of these refinements was the use of a larger truss support rig, which was selected to provide sufficient clearance for the aircraft. The rig also provided regular holes where the microphones’ support arms could be mounted; the rigid structure possessed no flat faces and minimal cylindrical truss structures to minimize scattering of reflected signals. In addition to the lighting rig array, a number of additional microphones were placed along the flight path, and in-plane but outside of the measurement array for validation of the acoustic sources. With this improved array, another measurement of a multi-rotor aircraft was conducted, equivalent acoustic sources constructed, and validation performed. This measurement validates the use of the square array to characterize these types of aircraft.

The atypical chemokine receptor 2 reduces T cell expansion and tertiary lymphoid tissue but does not limit autoimmune organ injury in lupus-prone B6lpr mice.

The atypical chemokine receptor 2 (ACKR2) is a chemokine scavenger receptor, which limits inflammation and organ damage in several experimental disease models including kidney diseases. However, potential roles of ACKR2 in reducing inflammation and tissue injury in autoimmune disorders like systemic lupus erythematosus (SLE) and lupus nephritis are unknown, as well as its effects on systemic autoimmunity. To characterize functional roles of ACKR2 in SLE, genetic Ackr2 deficiency was introduced into lupus-prone C57BL/6lpr (Ackr2-/- B6lpr) mice. Upon inflammatory stimulation in vitro, secreted chemokine levels increased in Ackr2 deficient tubulointerstitial tissue but not glomeruli. Moreover, Ackr2 expression was induced in kidneys and lungs of female C57BL/6lpr mice developing SLE. However, female Ackr2-/- B6lpr mice at 28 weeks of age showed similar renal functional parameters as wildtype (WT)-B6lpr mice. Consistently, assessment of activity and chronicity indices for lupus nephritis revealed comparable renal injury. Interestingly, Ackr2-/- B6lpr mice showed significantly increased renal infiltrates of CD3+ T and B cells, but not neutrophils, macrophages or dendritic cells, with T cells predominantly accumulating in the tubulointerstitial compartment of Ackr2-/- B6lpr mice. In addition, histology demonstrated significantly increased peribronchial lung infiltrates of CD3+ T cells in Ackr2-/- B6lpr mice. Despite this, protein levels of pro-inflammatory chemokines and mRNA expression of inflammatory mediators were not different in kidneys and lungs of WT- and Ackr2-/- B6lpr mice. This data suggests compensatory mechanisms for sufficient chemokine clearance in Ackr2-deficient B6lpr mice in vivo. Analysis of systemic autoimmune responses revealed comparable levels of circulating lupus-associated autoantibodies and glomerular immunoglobulin deposition in the two genotypes. Interestingly, similar to kidney and lung CD4+ T cell numbers and activation were significantly increased in spleens of Ackr2-deficient B6lpr mice. In lymph nodes of Ackr2-/- B6lpr mice abundance of activated dendritic cells decreased, but CD4+ T cell numbers were comparable to WT. Moreover, increased plasma levels of CCL2 were present in Ackr2-/- B6lpr mice, which may facilitate T cell mobilization into spleens and peripheral organs. In summary, we show that ACKR2 prevents expansion of T cells and formation of tertiary lymphoid tissue, but is not essential to limit autoimmune tissue injury in lupus-prone B6lpr mice.

Leveraging bioanalytical characterization of fractionated monoclonal antibody pools to identify aggregation-prone and less filterable proteoforms during virus filtration.

Monoclonal antibodies (mAbs) are an essential class of biotherapeutics. A platform process is used for mAb development to ensure clinically safe and stable molecules. Regulatory authorities ensure that mAb production processes include sufficient viral clearance steps to achieve less than one virus particle per million doses of product. Virus filtration is used for size-based removal of enveloped and nonenveloped viruses during downstream processing of mAbs. Process development in mAb purification relies on empirical approaches and often includes adsorptive prefiltration to mitigate virus filter fouling. Opportunities for molecular-level prediction of mAb filterability are needed to plug the existing knowledge gap in downstream processing. A molecular-level approach to understanding the factors influencing mAb filterability may reduce process development time, material loss, and processing costs due to oversized virus filters. In this work, pH step gradient fractionation was applied on polished bulk mAb feed to obtain concentrated pools of fractionated mAb variants. Biophysical properties and quality attributes of fractionated pools, including oligomeric state (size), isoelectric point profile, diffusion interaction parameters, and glycoform profile, were determined using bioanalytical methods. Filterability (loading and throughput) of fractionated pools were evaluated. Statistical methods were used to obtain correlations between quality attributes of mAb fractions and filterability on the Viresolve Pro virus filter.

Implementation of a Stereoscopic Camera System for Clinical Electron Simulation and Treatment Planning

PurposeA 3D stereoscopic camera system developed by .decimal was commissioned and implemented into the clinic to improve the efficiency of clinical electron simulations. Capabilities of the camera allowed simulations to be moved from the treatment vault into any room with a flat surface that could accommodate patient positioning devices, eliminating the need for clinical patient setup timeslots on the treatment machine. This work describes the process used for these simulations and compares the treatment parameters determined by the system to those used in delivery. MethodsThe Decimal3D scanner workflow consisted of: scanning the patient surface; contouring the treatment area; determining gantry, couch, collimator, and source-to-surface distance (SSD) parameters for en face entry of the beam with sufficient clearance at the machine; and ordering custom electron cutouts when needed. Transparencies showing the projection of in-house library cutouts at various clinical SSDs were created to assist in choosing an appropriate library cutout. Data from 73 treatment sites were analyzed to evaluate the accuracy of the scanner-determined beam parameters for each treatment delivery. ResultsClinical electron simulations for 73 treatment sites, predominately keloids, were transitioned out of the LINAC vault using the new workflow. For all patients, gantry, collimator, and couch parameters along with SSD and cone size were determined using the Decimal3D scanner with 57% of simulations using library cutouts. Tolerance tables for patient setup were updated to allow differences of 10, 20 and 5 degrees for gantry, collimator and couch, respectively. Approximately 7% of fractions (N=181 total fractions) were setup outside of the tolerance table based on physician-direction during treatment. This reflects physician preference to adjust the LINAC rather than patient position during treatment setup. No scanner-derived plan was untreatable due to cutout shape inaccuracy or clearance issues. ConclusionClinical electron simulations were successfully transitioned out of the LINAC vault using the Decimal3D scanner without loss of setup accuracy as measured through machine parameter determination and electron cutout shape.

수중에서의 무게추 중량과 수심의 상관성 조사

This study is one of the basic experiments for the development of a weight type water level gauge. The weights are made of polyvinyl chloride (PVC) with a density of 1.1-1.35 g/cm3, in cylindrical shapes of different sizes. The weights come in different diameters: 5, 6, 7, and 8 centimeters, and two different lengths: 20 and 30 centimeters. The weight of the weights was measured using a load cell and the inverse relationship of weight change with increasing depth was investigated. Also, by adjusting the gap between the weight and the outer casing, the distance at which the error in the weight observation due to the surface tension of water of 72.75 dyne/cm (20℃) was not affected was determined. In conclusion, we found that the larger the diameter of the weight and the smaller the height, the better the correlation with the water depth. Also, considering contamination of the PVC weight and manufacturing precision, it was determined that the space between the PVC weight and the external case required more than 1cm. A buoyancy type water level gauge requires the smallest possible weight diameter and sufficient clearance.

Analysis of Breakdown Phenomena of SF6-Gas Using Different Electrodes Configuration in High Voltage Application

This research investigates the breakdown voltage of SF6 gas using several electrode configurations, including Sphere-sphere, Rod-rod, Plate-plate, Sphere-plate, and Rod-plate, to guarantee sufficient clearance for an acceptable insulation level. The objective of the various electrode geometries is to produce a homogeneous and non-homogeneous electric field wherein the SF6 gas breakdown could be analyzed. The simulation under the influence of six gaps length be-tween electrodes (0.5cm, 1cm, 2cm, 3cm, 4cm, 5cm) were conducted. The lowest breakdown voltage is found in the Rod-rod electrode arrangement, followed by Plate-plate and Sphere-sphere electrode configuration. Compared with the Sphere-sphere electrode design, the Rod-rod electrode configuration is also asymmetric, with a substantially more inhomogeneous electric field. Based on the results, the Rod-plate and Sphere-plate arrangements appear to be asymmetrical. In the event of discharge and breakdown voltage, different electrode configurations have a significant influence. This study helps to identify the most suitable clearance and electrodes configuration in high voltage SF6 circuit breakers. A few researches were performed to find the breakdown voltage of SF6 gas in medium voltage applications under homogeneous electric stress. Some research paper also studied to find the breakdown voltage of SF6 gas under different temperature and pressure. However, this paper is based on finding out the breakdown voltage of SF6 gas in high voltage application providing homogeneous and non-homogeneous electric stress. This homogeneous and non-homogeneous electric field is designed using different electrodes configuration.

Assessing the morphological changes on the operation performance of canal: a case study of the Suez Irrigation Canal, Egypt

Abstract Morphological changes along the cross-section of canals affect the canal's performance to fulfill the desired operations. The Suez Irrigation Canal is a vital canal that provides the surrounding region with drinking water via about 21 drinking water treatment plants and serves about 140,000 feddan of irrigated land. However, the actual canal capacity is incapacitate to convey sufficient water for drinking and irrigation necessities. This research particularly evaluates the morphological changes in the Suez Canal's performance and increasing its ability to transport the required discharges with adequate operations. For this purpose, extensive field measurements and a numerical model (SOBEK 1D) were adapted to evaluate the canal capacity and operation under the required flow conditions. In total, 890 canal cross-sections were surveyed and 16-flow discharge measurements were considered to identify the actual geometric and hydraulic characteristics. The SOBEK 1D model was used to simulate different scenarios of canal cross-sections under changing flow conditions. The results showed that the actual canal mainly suffered from sedimentations that reduced the canal's capacity to transport the design flow discharges. In summary, rehabilitation of the canal is intensely recommended, in addition to the planned and sufficient clearance activatesof the canal to keep effective operations.

Preemptive alcohol septal ablation prior to transcatheter mitral valve replacement.

Alcohol septal ablation (ASA) has been shown to increase the neo-left ventricular outflow tract (LVOT) area before transcatheter mitral valve replacement (TMVR) but there is little literature on its success and use with dedicated devices. To describe our experience with preemptive ASA to increase the predicted neo-LVOT area and its utility with both dedicated TMVR devices and balloon-expandable valves. All patients who underwent ASA for TMVR candidacy in our center between May 2018 and October 2022 and had computed tomography(CT) scans done before and after ASA were included. Each CT was assessed for the minimum predicted neo-LVOT area at end-systole, using a virtual valve of the desired TMVR device for each patient. The primary outcome was an increase in the predicted neo-LVOT area after ASA that was deemed sufficient for safe implantation of the desired TMVR device. The secondary outcome was the absence of acute LVOT obstruction after TMVR. A total of 12 patients underwent ASA and all but 1 (n = 11, 91.6%) achieved the primary outcome of having sufficient predicted neo-LVOT area to proceed with TMVR. The mean increase in neo-LVOT area after ASA was 126 ± 64 mm2 (median 119.5, interquartile range: 65.0-163.5 mm2 ). Two patients (16.7%) required a permanent pacemaker after ASA. Nine patients went on and underwent TMVR with their respective devices and none had LVOT obstruction after the procedure. Among the remaining three patients, one had insufficient neo-LVOT clearance after ASA, one had unrelated mortality before TMVR, and one had advanced heart failure before TMVR. In appropriately selected patients and at centers experienced with ASA, preemptive ASA can achieve sufficient neo-LVOT clearance for TMVR with a variety of devices in approximately 90% of patients.

Planning of Mobile Crane Walking Operations in Congested Industrial Construction Sites

The trend toward more compact designs and congested site layouts makes it challenging for lift planners to provide feasible lift paths for mobile cranes, confronting the added risk of potential collisions when maneuvering through on-site obstacles. In some cases, particularly in congested industrial modular projects, it is inevitable for mobile cranes to walk with loads to a position with sufficient clearance to perform the lifts and place the objects in their final set position. This study contributes to the body of knowledge by introducing a comprehensive lift planning framework to plan complicated lifts involving mobile crane walking operations. Due to the lack of reliable and accurate plans for such lifts in practice and the added complexities, they are often eluded by practitioners compared with the more straightforward pick-and-set scenarios. This study proposes an algorithm for optimized planning of crane walking–involved lift operations borrowing an obstacle avoidance technique from robotics. The proposed path planner thoroughly considers site constraints and crane configurations to prevent collision between the crane body and the load with preinstalled objects. Actual case studies are presented to validate the efficiency of the proposed algorithm. The system generated the presented real-world lift in less than 5 min, satisfying the operations’ optimality, safety, and feasibility.

New Packaging Technology for 2-dimensional VCSEL Arrays and Their Electro-Optical Performance and Applications

At IMAPS2021, we reported on 1-dimensional VCSEL arrays and the packaging technology developed for these arrays, but this time we present the manufacturing workflow and look at the challenges presented by the packaging of special long-wavelength 2-dimensional vertical-cavity surface-emitting laser (VCSEL) arrays in various dimensions. We will show that available packaging technologies for epoxy application by silk screening, die- and wire bonding can be adapted for the unique properties of the 2D VCSEL arrays, delivering high accuracy for production with great overall yield. Proof of the excellent reliability and lifetime will be given through mechanical and electro-optical testing results. The technologies developed for 2D laser arrays will enable new devices for various new applications like high channel count interconnects for data communication and high power VCSEL solutions for 3D sensing. The perfected wire bonding process secured a homogeneous monometallic structure of the wire bonds, a reduced, well defined bond loop height, with sufficient clearance of the bonding wire above the VCSEL surface. Properly set-up manufacturing procedures for the packaging of the VCSEL arrays are necessary to achieve high performance and reliability of the products presented. Processing of large 2D-VCSEL arrays will be part of the paper. 2D arrays have enabled VCSEL technologies to address a wide range of new laser-based sensing applications. VCSEL products vary from laser chips with only a few emitters for proximity sensors up to several thousands of emitters for LiDAR systems. Applications include systems for the automotive, industrial, medical and consumer markets. There is a strong and growing market opportunity for long wavelengths VCSELs, e.g. based on InP material enabling single mode and multi-mode 2D-VCSEL arrays from 1.3 to beyond 2 µm. For 3D sensing systems and free-space optical communication, long wavelength 2D-VCSEL arrays offer improved eye safety and further benefits. The long wavelength VCSELs discussed in this paper can be deployed in a wide range of sensing and optical communication applications.

Аналіз конструктивних особливостей мініобприскувачів для невеликих фермерських господарств

The purpose of the study is to perform an analysis of the design characteristics and efficiency of various types of mini-sprayers in small areas of row crops and to form criteria by which a new self-propelled mini-sprayer with a rod stabilization system should be designed. An analysis of the efficiency of various types of mini-sprayers in small areas used for planting various crops in small farms was carried out. For the outlined areas of treatment of field crops (within 0.2 hectares), it was established that knapsack sprayers require a significant amount of physical labor of the operator: to move the mass of the sprayer with the working fluid, pumping with a manual pump (for the option without an electric pump), frequent refueling. In addition, manual movement of the rod cannot guarantee the uniformity of application of the working preparation over the entire area, especially with continuous application. For wheelbarrow sprayers, it is established that their mass is transferred to the chassis, but the operator must push it to move. If we talk about the inter-row of plants, then a furrow is formed in the loose soil, which greatly complicates the movement of such a sprayer. In addition, small ground clearance and unregulated furrow do not allow movement by inter-rows of row crops. In the option of using a hinged rod, it is difficult to maintain a constant speed of movement if the sprayer is moved manually. When using the mini energy tool, the same issues arise – a small clearance of the energy tool and the inability to adjust the furrow width. There is also no rod stabilization system. Hinged sprayers are more dependent on the parameters of the power supply chassis. Here, mainly, the same problems arise – limited adjustment of furrow width and fixed clearance, which narrows their use in certain phases of plant growth, when the ground clearance of the energy source is insufficient to avoid damaging plants during processing. In addition, the absence of a rod stabilization system can be seen. This leads to its oscillations, which are transmitted from the wheels of the energy store when moving by field irregularities, and this has an effect on the uniformity of the introduction of the operating solution and the resource of work. Regarding trailed mini-sprayers, it is possible to eliminate some of the described drawbacks in their designs, but their functionality is significantly limited by the parameters of the energy tools with which they are aggregated. To increase the efficiency of applying the operating solution to the treated areas, at least the simplest pendulum suspensions should be used to stabilize the rod. In order to improve the quality of application of the operating solution on the treated surfaces, universal use for processing various crops, including work in gardens, reducing the manual labor of the operator, etc., it is necessary to develop a self-propelled small-sized sprayer, analogues of which are not observed on the Ukrainian market. The following requirements are put forward to the developed design: self-moving (using an engine); the ability to change the furrow width using service mechanisms; have sufficient clearance or regulate it; the hinged rod must have a stabilization system and be adjustable in height of the installation; the pressure line must maintain a constant and controlled pressure of the operating solution; the developed model of a self-propelled sprayer should be affordable for the average agricultural producer in the subsistence farming. Taking into account these requirements and the implementation of the sprayer design in practice, we will get a highly efficient and competitive machine in the mini sprayer market.

Evaluation of Different Modes for Yarding Windthrown Timber with a Double-Hitch Carriage

Yarding whole trees is the most efficient way of extracting timber in steep terrain and allows reaping the combined benefits of mechanization and biomass recovery. In downhill yarding, however, whole-tree extraction is associated with a greater risk of loosening rocks or debris by the incoming loads as they bounce around along the extraction corridor. That may also cause damage to the cables and anchors by corresponding shock loads, ultimately endangering the yarder and its crew. To avoid these risks, »double-hitch carriages« can be employed. They combine a conventional motorized dropline carriage with a secondary carriage (»trailer«), equipped with a further, independent dropline winch. Thus, loads can be attached at two points and transported fully suspended above the ground in a horizontal position.Operation of these carriages may not be limited to the »horizontal« mode: the main carriage could also be operated without trailer (»single« mode), or separate loads may be attached to the two droplines (»double« mode), but their impact on the efficiency and economy of yarding operations is yet unknown. Therefore, the present study investigated how these modes affect the productivity and cost of downhill whole tree yarding. To this end, a classic time and motion study was conducted during a salvage logging operation in Northern Italy under a strictly controlled experimental design.Average productivity (18.2±7.2 to 24.5±15.4 m³ PSH0-1 merchantable volume per productive system hour excluding delays) and extraction cost (18 to 20 Euro m-³) did not differ significantly between treatments, while load composition and time consumption by task did. More (2.2±0.5) pieces per load were yarded under the »double«, than under the »single« (1.4±0.5) and »horizontal« (1.1±0.3) treatments. Inhaul speed (3.1±0.6 m s-1) was significantly higher under the »horizontal« treatment, which compensated for increased loading time derived from attaching the load at least at one point outside the corridor. Unloading took significantly longer under the »double« treatment, as loads had to be dropped successively due to the confined conditions on the landing. Though slowest (2.5±0.9 m s-1) during inhaul, the »single« treatment exhibited none of the other treatments disadvantages and larger loads could be accumulated due to partial suspension. From an economic viewpoint, the »horizontal« mode may only be warranted over yarding distances substantially beyond average. On shorter ones, it must be justified by other reasons, such as minimizing product contamination, soil disturbance or excessive strain to the skyline when the terrain profile impedes sufficient ground clearance.

Phosphate-Trapping Liposomes for Long-Term Management of Hyperphosphatemia.

Hyperphosphatemia is a typical complication of end-stage renal disease, characterized by elevated and life-threatening serum phosphate levels. Hemodialysis does not enable sufficient clearance of phosphate, due to slow cell-to-plasma kinetics of phosphate ions; moreover, dietary restrictions and conventional treatment with oral phosphate binders have low success rates, together with adverse effects. Here, we developed a new concept of phosphate-trapping liposomes, to improve and prolong the control over serum phosphate levels. We designed liposomes modified with polyethylene glycol and encapsulated with the phosphate binder ferric citrate (FC liposomes). These liposomes were found to trap phosphate ions in their inner core, and thereby lower free phosphate ion concentrations in solution and in serum. The FC liposomes showed higher phosphate binding ability as phosphate concentrations increased. Moreover, these liposomes showed a time-dependent increase in uptake of phosphate, up to 25 h in serum. Thus, our findings demonstrate effective long-term phosphate trapping by FC liposomes, indicating their potential to reduce serum phosphate toxicity and improve current management of hyperphosphatemia.

Respiratory physiotherapy in patients with cystic fibrosis and upper limb deep vein thrombosis.

We report physiotherapy management of two patients with severe cystic fibrosis (CF) lung disease and upper limb deep vein thrombosis (DVT). These patients were admitted due to a pulmonary exacerbation. Following peripherally inserted central catheters, they were diagnosed with an upper limb DVT. Due to their underlying lung disease, physiotherapy was mandatory for improvement. However, the DVT and anticoagulation treatment raised concerns for pulmonary emboli and hemoptysis. A framework for physiotherapy management in these patients, using a set of precautions and restrictions to maintain airway clearance while minimizing the risk for pulmonary emboli and hemoptysis, was established. Using this set of instructions, the patients experienced no major adverse events while maintaining sufficient airway clearance to allow respiratory improvement. These precautions were continued until the upper limb DVTs were resolved. To our knowledge, there are currently no guidelines or expert opinions available. Therefore, this framework can help guide physiotherapy management.

Patient-Customized Theatre Mattress Supports for Spinal Surgery: A Pilot Study Presenting a Novel Engineering Virtual Design and Manufacturing Technique

Abstract Optimal patient positioning for spine surgery is vital for surgical success and the minimization of complications intra-/postoperatively. In patients with complex comorbidities, commercially available surgical positioning equipment is inadequate. To overcome this, a novel method was developed to create custom-fit patient-specific theater mattresses for patients undergoing spine surgery. An innovative digital workflow involving three-dimensional (3D) surface scanning, 3D simulation, and computer-aided design was developed to manufacture customized theater supports with patient-specific requirements. These supports offered the surgeon an enhanced ability to relieve load bearing on prominent anatomical features or where desired, to tailor the support surface to the patient's anatomy for lengthy surgery. The bespoke theater mattress was evaluated by whether the support resulted in a complication-free surgery. Using this new workflow, case examples for two patients with complex comorbidities were described. The spine surgeon and anesthetist reported the patient-specific custom mattresses were fit as per the required design, provided sufficient clearance around anatomical prominences and areas that required to be unloaded, had sufficient clearance for the anesthetic method and cannulation, provided excellent surgical access and stability during surgery, and postoperatively no soft tissue overload over bony prominence and implanted devices. Positive patient outcomes after successful lengthy surgical interventions were associated with these patient-specific, contoured mattress supports. Future projects will seek to utilize this technology for other types of surgeries and intra-operative positioning requirements, and for a broader demographic of patients in both the pediatric and adult setting.

Piloted Simulation of the Rotorcraft Wind Turbine Wake Interaction during Hover and Transit Flights

Helicopters are used for offshore wind farms for maintenance and support flights. The number of helicopter operations is increasing with the expansion of offshore wind energy, which stresses the point that the current German regulations have not yet been validated through scientific analysis. A collaborative research project between DLR, the Technical University of Munich, the University of Stuttgart and the University of Tübingen has been conducted to examine the sizes of the flight corridors on offshore wind farms and the lateral safety clearance for helicopter hoist operations at offshore wind turbines. This paper details the results of piloted helicopter simulations in a realistic offshore wind farm scenario. The far-wake of rotating wind turbines and the near-wake of non-rotating wind turbines have been simulated with high-fidelity computational fluid dynamics under realistic turbulent inflow conditions. The resulting flow fields have been processed by superposition during piloted simulations in the research flight simulator AVES to examine the flight corridors in transit flights and the lateral safety clearance in hovering flights. The results suggest a sufficient size for the flight corridor and sufficient lateral safety clearance at the offshore wind turbines in the considered scenarios.

Abstract P3-20-01: Increased distant recurrence following margin involvement in early invasive breast cancer in two large UK cohorts

Abstract Involved margins after surgery for early breast cancer increase the risk of local recurrence (LR), but international guidelines suggest that’ no tumour’ on ink is sufficient margin clearance after breast conserving surgery (BCS). Data on the effect of margin clearance on distant recurrence (DR) are lacking. Our aim was to determine the association between margin involvement, recurrence (DR) and breast cancer deaths. Methods Data from breast cancer units in Greater Manchester (GM) and the UK National Cancer Registry (NCRAS) were analysed. Margin status was prospectively recorded after surgery according to National Health Service Breast Screening Pathology (NHSBSP) minimum pathology data standards All patients underwent curative surgery and received adjuvant therapy according to local guidelines. Patients not undergoing curative surgery(T4, inflammatory or metastatic cancer) were excluded .Cox-proportional hazards models investigated factors associated with LR, DR and risk of breast cancer death.NCRAS records breast cancer deaths . Results GM analysis included 3270 patients from 2010 to 2014, 2295 (70.2%) had margins (>2mm) ,302 (9.2%) close (1-2mm) margin clearance and 673 (20.6%) involved (<1mm) margins. Median age was 61 years (range 24-100 years) and median follow up was 64.4 months (range 0.0-126.6 months). Breast Conserving Surgery (n=2030) and Mastectomy (n=1240) surgery was used as appropriate and most patients underwent adjuvant radiotherapy (71%) and/or hormone therapy (84%).160 patients (4.9%) developed LR and 231 patients (7.06%) DR. Time-to-DR (p=0.035) and time-to-LR (p=0.012) differed by margin status. At 5-years, the probability of LR was 3.1%, 3.5% and 5.8% and for DR was 4.9%, 5.9% and 7.1% for clear, close and involved margins, respectively. After multivariable adjustment, involved margins<1mm were associated with increased hazard of DR (HR 1.459, 95% CI: 1.050, 2.027, p=0.025) and LR (HR 1.79, 95% CI: 1.21, 2.63, p=0.004) compared to a clear margin>2mm. For Breast Conservation margins<1mm increased DR (HR 2.09,1.22-3.58:p<0.009 ) compared to clear margins. Similar findings were found in several subgroup analyses including screening, symptomatic and by cancer treatments. NCRAS data from 2010-2013 included 40,849 patients with invasive cancer of whom 27,589 margins >1mm (67.5%) and 3,935 (9.6%) were classed as “clear margins” and 9,325 (22.8%) cancer patients had involved margins <1mm, There were 3,160 deaths from breast cancer with a median follow-up of 80.2 months. Multivariate analysis in NCRAS indicated excess cancer mortality (HR 1.18 (95% CI 1.08-1.28) in the 9325 (22.8%) patients with margins <1mm (p<0.001), tumour stage (stage 3 HR 7.01 (6.28-7.82), p<0.001), age (HR 1.02 (1.02-1.03, p<0.001), symptomatic detection (HR 2.21 (1.98-2.46), p<0.001) and lower socio-economic status HR 1.31 (1.16-1.47, p<0.001). Conclusions Margins>1mm were associated with reduced DR and should be essential surgical management. Current guidelines about surgical margins need to be re-evaluated to achieve reduced DR and cancer deaths. Citation Format: Nigel James Bundred, Sarah Michael, John Broggio, Anne Armstrong, Glen Martin, Mohamed Absar, Jane Ooi. Increased distant recurrence following margin involvement in early invasive breast cancer in two large UK cohorts [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-20-01.

Capillary transfer: Numerical study of how topology affects the fluid flow rate into a planar microstructure with pseudopotential multiphase Lattice-Boltzmann method

We investigate how topology impacts capillary action with the hope of aiding future thermal engineering decisions. Heat pipes and their two-dimensional variant, vapor chambers are essential components in electronics cooling. With thin-film evaporation as the driving force for such high-heat-flux movers, studies have been done to optimize the thermal performance of different designs. However, the fundamental problem of liquid transportation needs to be addressed exclusively: evaporation can only work as long as the new liquid is continuously being replaced. The device achieves this by the capillary process (or wicking) through the thermal ground (or wicks): a configuration of microstructures attached to the device's walls. Some planar topologies of the structure allow for consistent but slower mass feeding; others offer higher bandwidth but with local flow hindrance, creating a pulsating tendency; certain conditions would even block the capillary flow. Surveying the capillary performance of different two-dimensional designs of the thermal ground, we encounter a topological factor that correlates with this mass transfer rate. We incorporate in the factor the wick's width, its height, and the gap between one microstructure to another. An energy model is studied to explain the underlying influence of the structure topology, while Lattice-Boltzmann method is used to evaluate the capillary dynamics inside the thermal ground. With ultra-thin applications in mind, the paper looks at the length scales of micrometers with a wick height of 50 μm. Overall, we find that tightly packed structures pull the most liquid in the same amount of time; however, we find that two core constraints need to be met: sufficient clearance between structures and freedom of mobility.