Pivot Point Research Articles

Performance Analysis of Axially Loaded Secant Pile Wall Embedded in Sand: An Experimental Investigation

In urban environments, temporary excavation support systems (ESSs) are intensively recommended during the construction process of structures with underground levels to preserve nearby structures and maintain the excavation sides. Once the foundations and basements are constructed, these systems are rendered useless. As a result, integrating the temporary ESS into the building foundation may have significant benefits. Therefore, the main aim of this paper was to investigate the behavior of Secant Pile Walls (SPWs) through fifteen model tests with an acceptable scale on an axially loaded SPW embedded in medium and dense sand. This study considered several factors to define wall behavior, such as normalized lateral deflection (δh/Ht%), the vertical deflection of the SPW (δvw/Ht%), vertical ground settlement (δv/Ht%), and settlement influence zone (Do). These factors were investigated and analyzed under the influence of a set of parameters including normalized penetration depth (He/Hc), sand relative density (Dr), and surcharge load density (Wsur). The findings demonstrated that SPWs had structural and overall stability features to withstand lateral earth pressures as well as applied axial loads. Generally, increasing the He/Hc ratio further than a limit value of 2.0 for the same surcharge load had a limited impact on the ultimate axial capacity, particularly in the case of dense sand. The location of the pivot point (ε′) extended from 0.24 to 0.41He from the wall tip, with a mean value of 0.34He and 0.29He for the values of Dr = 80 ± 2%, and 60 ± 2%, respectively. Other issues were also discussed for selected samples, including an analysis of the wall's bending moments and any potential wall buckling. Finally, to correlate the experimental data with the theoretical values, a modification factor for the pile static formula was developed by using nonlinear regression analysis with a significant prediction accuracy with an R2 of 0.94.

Chirality-Specific Unidirectional Rotation of Molecular Motors on Cu(111).

Molecular motors have chemical properties that enable unidirectional motion, thus breaking microscopic reversibility. They are well studied in solution, but much less is known regarding their behavior on solid surfaces. Here, single motor molecules adsorbed on a Cu(111) surface are excited by voltages pulses from an STM tip, which leads to their rotation around a fixed pivot point. Comparison with calculations shows that this axis results from a chemical bond of a sulfur atom in the chemical structure and a metal atom of the surface. While statistics show approximately equal rotations in both directions, clockwise and anticlockwise, a detailed study reveals that these motions are enantiomer-specific. Hence, the rotation direction of each individual molecule depends on its chirality, which can be determined from STM images. At first glance, these dynamics could be assigned to the activation of the motor molecule, but our results show that this is unlikely as the molecule remains in the same conformation after rotation. Additionally, a control molecule, although it lacks unidirectional rotation in solution, also shows unidirectional rotation for each enantiomer. Hence, it seems that the unidirectional rotation is not specifically related to the motor property of the molecule. The calculated energy barriers for motion show that the propeller-like motor activity requires higher energy than the simple rotation of the molecule as a rigid object, which is therefore preferred.

Two-mirror aerial mapping camera design with a tilted-aplanatic secondary mirror for image motion compensation.

The optical compensation method is a promising method to compensate the image motion by driving the optical element of the system. However, the tilt motion of the optical element could induce the degradation of the image quality. Based on the Nodal Aberration Theory (NAT), this paper proposes a novel optical image motion compensation design with a secondary tilt-aplanatic two-mirror optical system (STATOS), which achieves the insensitivity on the image quality of the optical system. First, the properties of coma-free pivot point depending on the location of stop at primary mirror or secondary mirror have been analyzed respectively. Then the calculating method about construction parameters in terms of STATOS is developed. Further, the maximum tilt angle of secondary mirror could be solved using NAT under ordered specific restriction. Finally, a prototype is designed with SM-tilting result of MTF value maintain above 0.32 at the cut-off frequency of detector, where the principal distance could remain stable and the changed distortion is better than 0.03%. A test flight has been carried out to prove the desired results and feasibility of STATOS used in an aerial mapping camera.

Ultrastructure of a Mechanoreceptor of the Trichoid Sensilla of the Insect Nabis rugosus: Stimulus-Transmitting and Bio-Sensory Architecture.

This paper presents the ultrastructure morphology of Nabis rugosus trichoid sensilla using SEM and TEM data, along with a two-dimensional model of the trichoid sensilla developed in Amira software. The SEM images show the shape and scattering of the trichoid mechanosensilla over the N. rugosus flagellomere. The TEM images present the ultrastructural components, in which the hair rises from the socket via the joint membrane. The dendrite sheath is connected at the base of the hair shaft, surrounded by the lymph space and the socket septum. This dendrite sheath contains a tubular body with microtubules separated by the membrane (M) and granules (Gs). This study presents a model and simulation of the trichoid sensilla sensing mechanism, in which the hair deflects due to the application of external loading above it and presses the dendrite sheath attached to the hair base. The dendrite sheath is displaced by the applied force, transforming the transversal loading into a longitudinal deformation of the microtubules. Due to this longitudinal deformation, electric potential develops in the microtubule's core, and information is delivered to the brain through the axon. The sensilla's pivot point or point of rotation is presented, along with the relationship between the hair shaft length, the pivot point, and the electric potential distribution in the microtubules. This study's results can be used to develop ultra-sensitive, bioinspired sensors based on these ultrastructural components and their biomechanical studies.

A Practical Method for Calculating Soil Mixing Wall Retaining Structure by Means of a “Simple Beam Method”

SMW is the abbreviation of soil mixing wall. H‐type steel, also known as the new cement mixing pile wall, is inserted into the cement pile, which combines the bearing load with the impervious water retaining, and has the two functions of stress and impervious retaining wall of the supporting structure. In the design of conventional foundation pit engineering, the active Earth pressure calculated by Rankine’s theory is not consistent with the engineering practice because the soil behind the retaining structure has not reached the limit equilibrium state. The embedded depth and the horizontal supporting force of the retaining structure are usually calculated with the equivalent beam method, but the method is complicated. Taking the supporting structure of a foundation pit called “soil mixing wall retaining wall and bolt” as a case, in this paper, the lateral pressure is used to calculate the active Earth pressure at any depth, and the “simple beam method” is used to calculate the embedded depth, the horizontal supporting force, and the internal force of the SMW continuous wall, which intends to find out the first and second supporting points as the pivots of the “simple beam method” under the most unfavorable conditions. When the first pivot is used as the supporting point of the “simple beam method,” the soil pressure is ignored because it is within the critical depth of the Rankine active Earth pressure; while the second pivot is used as the supporting point of the “simple beam method,” the forces on it are balanced to the torque of the second pivot, only considering the moment balance of the active and passive Earth pressure on the isolation body under the second pivot point. The results are in good agreement with the results of the equivalent beam method and the measured values, and they are much closer to the measured values, which provides a practical method for designing SMW retaining structures.

A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

Using a compilation of Hα fluxes for 384 star-forming galaxies detected during the Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE), we study several important scaling relations linking the star formation rate, specific star formation rate, stellar mass, stellar mass surface density, and atomic gas depletion timescale for a complete sample of galaxies in a rich environment. The extraordinary sensitivity of the narrow-band imaging data allows us to sample the whole dynamic range of the Hα luminosity function, from massive galaxies (Mstar ≃ 1011 M⊙) to dwarf systems (Mstar ≃ 106 M⊙), where the ionised gas emission is due to the emission of single O-early B stars. This extends previous works to a dynamic range in stellar mass and star formation rate (10−4 ≲ SFR ≲ 10 M⊙ yr−1) that has never been explored so far. The main-sequence relation derived for all star-forming galaxies within one virial radius of the Virgo cluster has a slope comparable to that observed in other nearby samples of isolated objects, but its dispersion is about three times larger (∼1 dex). The dispersion is tightly connected to the available amount of HI gas, with gas-poor systems located far below objects of similar stellar mass, but with a normal HI content. When measured on unperturbed galaxies with a normal HI gas content (HI-def ≤ 0.4), the relation has a slope a = 0.92 ± 0.06, an intercept b = −1.57 ± 0.06 (at a pivot point of log Mstar = 8.451 M⊙), and a scatter σ ≃ 0.40, and it has a constant slope in the stellar mass range 106 ≲ Mstar ≲ 3 × 1011 M⊙. The specific star formation rate of HI-poor galaxies is significantly lower than that of HI-rich systems of similar stellar mass, while their atomic gas consumption timescale τHI is fairly similar, in particular, for objects of stellar mass 107 ≲ Mstar ≲ 109 M⊙. We compare these observational results to the prediction of models expressly tuned to reproduce the effects induced by the interaction of galaxies with their surrounding environment. The observed scatter in the main-sequence relation can be reproduced only after a violent and active stripping process such as ram-pressure stripping that removes gas from the disc (outer parts first) and quenches star formation on short (< 1 Gyr) timescales. This rules out milder processes such as starvation. This interpretation is also consistent with the position of galaxies of different star formation activity and gas content within the phase-space diagram. We also show that the star-forming regions that formed in the stripped material outside perturbed galaxies are located well above the main-sequence relation drawn by unperturbed systems. These extraplanar HII regions, which might be at the origin of ultra-compact dwarf galaxies (UCDs) and other compact sources typical in rich environments, are living a starburst phase lasting only ≲50 Myr. They later become quiescent systems.

Novel approach to assessing the primary stability of dental implants under functional cyclic loading in vitro: a biomechanical pilot study using synthetic bone.

This pilot study was conducted to develop a novel test setup for the in vitro assessment of the primary stability of dental implants. This was achieved by characterising their long-term behaviour based on the continuous recording of micromotions resulting from dynamic and cyclic loading. Twenty screw implants, each 11 mm in length and either 3.8 mm (for premolars) or 4.3 mm (for molars) in diameter, were inserted into the posterior region of 5 synthetic mandibular models. Physiological masticatory loads were simulated by superimposing cyclic buccal-lingual movement of the mandible with a vertically applied masticatory force. Using an optical 3-dimensional (3D) measuring system, the micromotions of the dental crowns relative to the alveolar bone resulting from alternating off-centre loads were concurrently determined over 10,000 test cycles. The buccal-lingual deflections of the dental crowns significantly increased from cycle 10 to cycle 10,000 (P<0.05). The deflections increased sharply during the first 500 cycles before approaching a plateau. Premolars exhibited greater maximum deflections than molars. The bone regions located mesially and distally adjacent to the loaded implants demonstrated deflections that occurred synchronously and in the same direction as the applied loads. The overall spatial movement of the implants over time followed an hourglass-shaped loosening pattern with a characteristic pivot point 5.5±1.1 mm from the apical end. In synthetic mandibular models, the cyclic reciprocal loading of dental implants with an average masticatory force produces significant loosening. The evasive movements observed in the alveolar bone suggest that its anatomy and yielding could significantly influence the force distribution and, consequently, the mechanical behaviour of dental implants. The 3D visualisation of the overall implant movement under functional cyclic loading complements known methods and can contribute to the development of implant designs and surgical techniques by providing a more profound understanding of dynamic bone-implant interactions.

Land marks and safety with respect to radial nerve in distal humeral surgery

The study analyzed 20 elbows from 10 preserved male human cadavers (10 right and 10 left), which were selected based on strict inclusion criteria. Cadavers with a history of prior surgery, infection, trauma or deformity were excluded from the sample. The average age of the cadavers was 46 years, ranging from 28 to 64 years. The precise measurements were obtained using the Microscribe-G2X device, renowned for its accuracy of up to one-thousandth of a millimeter. The length from the pivot point of the radial nerve in the sulcus nervi radialis to the distal end of the humerus is measured, along with the transverse diameter between the lateral epicondyle and the radial nerve and the length of the humerus itself. The length from the pivot point of the radial nerve in the sulcus nervi radialis to the distal end of the humerus is measured, along with the transverse diameter between the lateral epicondyle and the radial nerve and the length of the humerus itself. The length from the pivot point of the radial nerve in the sulcus nervi radialis to the distal end of the humerus is measured, along with the transverse diameter between the lateral epicondyle and the radial nerve and the length of the humerus itself. The right and left sides were measured to be 30.54±0.65cm and 30.54±0.59cm, respectively, with no considerable difference between them. The distance from the pivot point of the radial nerve in the sulcus nervi radialis to the distal part of the humerus was 15.07±1.27cm on the right side and 15.34±1.21cm on the left side. On the right, the distance was 15.07±1.27cm, while on the left, it was 15.34±1.21cm. Moreover, the transverse diameter between the lateral epicondyle and the radial nerve was measured at 2.95±0.14cm on the right side and 3.05±0.13cm on the left side. We contend that comprehension of the safe zone in distal humerus surgery can greatly improve surgical safety.

김종삼의 시적 정의(正義)

This paper aims to reveal the ‘poetic justice’ that Kim Jong-sam’s poetry embodies. The path from the emotion of sympathy implied in Kim Jong-sam's poem to public power was captured and analyzed as a 'virtuous cycle of sympathy'. We paid attention to the fact that ‘empathy’ revealed in the work becomes a pivot point for converting negative emotions such as loss and deprivation into tolerance, and as a result, the influence of empathy contributes to public judgment. The fact that sympathy forms the core of Kim Jong-sam's poetic world is that his life was aligned with the face of a painful other in the turbulent times of liberation, national division, and war. The virtuous cycle of sympathy, which is the driving force of Kim Jong-sam's poetry, is the context of poetic imagery that captures the shabby reality in the wretchedness of the times, and at the same time, his poetic pursuit through the course of the poem. This paper focuses on the path of sympathy that stands out in Kim Jong-sam's poem, and attempts to reveal the poet's vocation and poetic direction as he realizes it.

Complementary hepatic metabolomics and proteomics reveal the adaptive mechanisms of dairy cows to the transition period

The transition period from late pregnancy to early lactation is a vital time of the lifecycle of dairy cows due to the marked metabolic challenges. Besides, the liver is the pivot point of metabolism in cattle. Nevertheless, the hepatic physiological molecular adaptation during the transition period has not been elucidated, especially from the metabolomics and proteomics view. Therefore, the present study aims to investigate the hepatic metabolic alterations in transition cows by using integrative metabolomics and proteomics methods. Gas chromatography quadrupole-time-of-flight mass spectrometry-based metabolomics and data-independent acquisition-based quantitative proteomics methods were used to analyze liver tissues collected from 8 healthy multiparous Holstein dairy cows 21 d before and after calving. In total, 44 metabolites and 250 proteins were identified as differentially expressed from 233 metabolites and 3,539 proteins detected from the liver biopsies during the transition period. Complementary functional analysis of different metabolites and proteins indicated the upregulated gluconeogenesis, tricarboxylic acid cycles, AA degradation, fatty acid oxidation, AMP-activated protein kinase signaling pathway, peroxisome proliferator-activated receptor signaling pathway, and ribosome proteins in postpartum dairy cows. In terms of the metabolites and proteins, glucose-6-phosphate, fructose-6-phosphate, carnitine palmitoyltransferase 1A, and phosphoenolpyruvate carboxykinase played a significant role in these pathways. The upregulated oxidative status may be accompanied by the pathways mentioned above. In addition, the upregulated glucagon and insulin signaling pathways also indicated the significant requirement for glucose in postpartum dairy cows. These outcomes, from the view of global metabolites and proteins, may present a better comprehension of the biology of the transition period, which can be helpful in further developing nutritional regulation strategies targeting the liver to help cows overcome this metabolically challenging time.

Segmentation of continental Indian plate by the Narmada‐Son diffuse plate boundary

The Narmada‐Son lineament is a major tectonic feature in Central India. Here we employ data from geodetic measurements of crustal deformation and upper mantle P‐wave travel time tomography and propose that the Narmada‐Son palaeo‐rift is a present‐day diffuse plate boundary that segments the continental part of the Indian “composite” plate into two component plates, the North and South‐Indian plate. Tomographic images reveal that the collision of an indenter, associated with the relatively faster moving South‐Indian plate, with the Narmada‐Son diffuse plate boundary acted as a pivot point exerting a torque on one of the component plates along with mechanical rotation. This new proposal along with a new identity of the Narmada‐Son diffuse plate boundary is in better agreement with the estimated location of the relative Euler pole across two respective component plates. Our model is also able to better explain the Indian “composite” plate hypothesis, diversity in the topographic architecture along the rift, and contrasting deformation styles on either side of the diffuse plate boundary.

Association between B-lines on Lung Ultrasound, Invasive Hemodynamics and Prognosis in Acute Heart Failure Patients.

Increased left atrial pressure leads to pulmonary congestion. Although the B-lines in lung ultrasound (LUS) are useful in detecting pulmonary congestion, data regarding the association between B-lines and invasive hemodynamics are inconsistent. This study aimed to explore the correlation of the B-line count by LUS with pulmonary capillary wedge pressure (PCWP) stratified for preserved and reduced ejection fraction (EF) in acute heart failure patients. We performed a prospective observational study on 116 hospitalized patients with acute heart failure (mean age, 75.2 ± 10.3 years), who underwent right heart catheterization before discharge. LUS was performed in eight zones within 4 h of right heart catheterization and compared with PCWP separately in each EF group. Cardiac events were recorded 1 year after discharge. PCWP revealed a clear pivot point at which the B-lines began to increase in the overall cohort and each EF. Specific thresholds of the increase in B-lines were identified at 19 and 25 mmHg for preserved and reduced EF, respectively. Residual congestion at discharge was defined as the presence of ≥6 B-lines. Patients with residual congestion had a higher risk for cardiac events than those without residual congestion (hazard ratio, 12.6; 95% CI, 4.71-33.7; log-rank, P < 0.0001). A clear pivot point was associated with increased B-lines count in PCWP at 19 and 25 mmHg for preserved and reduced EF, respectively. Moreover, the increased B-line count above the defined cutoff used to quantify residual congestion was associated with significantly worse outcomes.

Development of automatic control methods of vessel rotation around the pivot point without drift

The object of research is the processes of automatic control of the vessel rotation around the pivot point with zero drift. In recent years, the number of vessels and their sizes has increased significantly, while the size of ports has grown much more slowly. There is an urgent need to optimize control processes, especially in compressed waters. One of the directions of such optimization is the use of the pivot point concept – an alternative vision of the vessel movement during its maneuvering. It is shown that the circulation radius and the position of the vessel on circulation are determined by the pivot point abscissa and ordinate. Linearized models of the two most common control schemes are considered: the control scheme of a single-screw conventional vessel without a bow thruster and the control scheme of a single-screw conventional vessel with a bow thruster. For the steady state of each of these schemes, controls were obtained that ensure the circulation of the vessel around a pivot point position without drift angle. This makes it possible to reduce the width of the traffic lane, increase traffic safety, reduce hydrodynamic resistance and fuel consumption, create favorable conditions for carrying out technological operations, for example, mooring, and reduce the influence of the human factor on control processes. The workability and effectiveness of the developed methods were verified by mathematical modeling of the MSС Container Ship (Dis. 32025t) automatic mooring without drift angle on the imitation modeling stand created by the authors on the basis of the Navi Trainer 5000 navigation simulator. The obtained capabilities are explained by the use of the mathematical model of the vessel in the on-board controller of the automated system and modern mathematical apparatus. The developed methods can be used on the vessels, provided to integration into the existing automated system of an on-board controller with open architecture, to increase the capabilities of automatic vessel movement control. Today, all automated systems already use the electronic principle of generating and transmitting signals from control devices (power plant telegraph, rudder, bow and stern thruster telegraphs and etc.) to executive devices, which greatly simplifies the integration of the on-board controller and the creation of a closed circuit of automatic control.

A biomechanical study shows the direction of compression influences the amount of lordosis gained in lumbar fusion

Study designBiomechanical model study. BackgroundLumbar lordosis is usually lost in the degenerative process, and when lumbar fusion is required, its restoration is one of the modern metrics of a successful operation.We sought to investigate the hypothesis that changing direction of compression during surgical fusion, would gain more lordosis. MethodsUsing a biomechanical Sawbones™ model we inserted polyaxial pedicle screws from S1 to L4. A rod was placed in the screws without requiring reduction. Markers were attached to the spinous processes to allow photographic analysis of lordosis. Two methods were compared. Method A - caudal screws were locked first and compression proceeded in a cranial direction prior to locking. Method B - cranial screws were locked first and compression proceeded caudally. Increasing levels of surgical invasiveness were tested; intact, interbody cage, inferior facet resection, and Ponte resection and using different rods including: lordotic, hyperlordotic and straight. FindingsMethod B demonstrated to be consistently superior to Method A, regardless of the type of rod used and for every level of surgical invasiveness performed. (P < 0.001). Interpretationlocking the top screws first was a consistently superior method of compression, gaining more lordosis.To explain this finding we suggest the following: During posterior compression of pedicle screws along a fixed rod, screw motion is limited by the conflict between the fixed lordotic rod position, and the need for the moving screw to move in a kyphotic arc which is determined by the cage which acts as a pivot point.

365 ANALYSIS OF PIVOT POINTS AND SLOW CONDUCTION AREAS IN PATIENTS UNDERGOING ATRIAL FIBRILLATION ABLATION

Abstract Introduction Little is known about progression of atrial fibrillation (AF) from paroxysmal to persistent form. Electrical remodeling may play a pivotal role in the arrhythmia transition. The aim of the study was the characterization of the atrial electrical substrate in patients suffering from AF. Methods Twenty-seven patients were included in the study (14 with paroxysmal AF and 13 with persistent AF). Two simultaneous electroanatomical maps of the left atrium were collected using PentaRay catheter using the parallel mapping feature [first map during sinus rhythm and a second one with an extrastimulus from coronary sinus (CS)]. We analyzed the propagation of the wavefront and we identified zones of abnormal conduction: slow conduction (SC) corridors and pivot points (PP). SC corridors were defined by the slowing of conduction velocity; pivot points were zones in which propagation pattern changed the direction of 90° or more. Maximum delay between the recording dipoles located at the extremities of the PentaRay splines was calculated. At each of these sites, EGMs were collected and analyzed in terms of amplitude and duration. We checked if areas of abnormal conduction during sinus rhythm were present or they disappeared by delivering an extrastimulus from the coronary sinus. Results The average number of collected EGMs per map was 4790 ± 1333 (PAF 4829 ± 1407; PsAF 4745 ± 1402). Total abnormal conduction areas in the 27 patients were 62, 65% of which were slow conduction. Pivot points and slow conduction manifested a trend to cluster in some areas: both of them were mostly present at the ostia of pulmonary veins, in a specific segment between LAA ostium and mitral annulus and in the posterior wall. During sinus rhythm, pivot points were 29, while pacing from distal CS catheter the same zones showed normal conduction in 14 cases: they were still present in 60% in PAF group and 50% in PsAF. Slow conduction corridors, instead, show a trend to remain while pacing from CS: 76% in the first group and 78% in the second one. Conclusions SC corridors are fixed alterations of atrial substrate, while pivot sites may be more dynamic entities: both of them may have a key role in remodeling atrial structures and atrial fibrillation progression and maintenance. These may represent future targets for AF therapy and prevention.

Acting on the Pivot Point

When facing opportunities, effective leaders trod a path that effectively incorporates ethical and empathetic leadership considerations and characteristics to drive change. The actions and impacts of two very different women facing challenges as change moments each tie back to Kouzes and Posner’s traits of exemplary leaders such as model the way and inspire a shared vision (Kouzes & Posner, 2017). Rear Admiral Meredith Austin, United States Coast Guard (retired), and Patricia (Trish) Foster, Executive Director Emeritus of Bentley University’s Center for Women in Business have led transformative changes. Admiral Austin was crucial in coordinating the early-pandemic smooth return of the Grand Princess cruise ship to the United States, as well as bringing together disparate agencies with competing priorities working to manage the wind-down of cruise ship operations and the repatriation of thousands of cruise ship employees to nations around the globe. Seeing opportunities for improvement, Foster was the architect, developer, and implementor of initiatives that inculcated diverse, equitable, and inclusive behaviors into the internal and external operations at Bentley University. While their work was very different, they each acted upon unique pivot points of opportunity, applying empathy and action to create a lasting impact for their communities while setting an example for long-term change.

Understanding State-of-the-Art Literature Reviews.

Understanding State-of-the-Art Literature Reviews.

Spatially Confined T-Cell Mediated Anti-AML Tumor Immunity By Dual Recognition Antibodies (CD123/CD200)

Definitive cure of acute myeloid leukemia (AML) remains an unmet need. While recombinant antibody-based and CAR-T cell mediated immunotherapies bear great potential in targeting chemotherapy-resistant leukemic stem cells, these approaches are largely limited by the lack of specific targets uniquely expressed by leukemic cells. Here, we propose a combinatorial strategy using a two-target approach which may have improved on-target and reduced off-target effects. The well-known stem cell marker interleukin-3 receptor α (CD123) is expressed on most AML cells. CD200 recently emerged as a cell surface marker mediating immuno-evasion on high-risk AML cells. We engineered the "Prodrug-activating chain Exchange"(PACE) TriFAB system (Dickopf S et al. Biological Chemistry, 2022) to yield a combinatorial anti-AML directed T-cell response. PACE-TriFAB educts are complementary Knob-into-hole IgG derived prodrugs in which one half is exchanged by a dummy containing an interface destabilizing mutation in the CH3 domain. The CH2 domain of the main body is replaced by a CD3 FAB light or heavy chain, respectively. With the hinge region being replaced by a flexible linker and therefore lacking disulfide bonds, a chain exchange between two educts is enabled when in close proximity on the cell surface. This leads to an activated anti CD3 domain and a dummy-dummy by-product. To demonstrate the T-cell activating potential, we co-cultured fresh PBMCs from healthy donors together with the CD200+/CD123+ AML cell line Kasumi-1 and checked T-cell activation by flow cytometry (E:T ratio 5:1, prodrug conc. 20 nM, 24 h stimulation). We observed a marked increase in CD69, CD25 and CD137 expression on CD8+ cells in the case when the CD123 and CD200 prodrugs were applicated simultaneously together with target cells, but not when single prodrugs alone or without target cells were analyzed (Median fluorescence intensity for CD25, CD69 and CD137: No construct: 450, 8.900 & 2.100; prodrug CD200: 460, 8.700 & 2.100; prodrug CD123: 460, 9.600 & 2.000; both prodrugs: 6.500, 344.300 & 43.100; results confirmed in repeat experiments) For the evaluation of the specific cytotoxic effect of the construct we transduced Kasumi-1 cells with an mCherry lentiviral vector and imaged the cells co-cultured with PBMCs every 2 h over a time span of 60 h (E:T ratio 5:1, prodrug conc. 10 nM). Proliferation of the Kasumi-1-mCherry cells was observed when no prodrug or only a single prodrug was added. However, application of both prodrugs together led to a decrease in mCherry positive cell count (log2 fold changes to starting point: No PBMCs 1,2; no construct 0,9; prodrug CD200 0,9; prodrug CD123 0,4; both prodrugs -2,1; n=3). Not only could we show that this elimination of tumor cells was dose dependent but also it was constrained by the E:T ratio (pivot point from killing to proliferation at 0,1 nM and E:T of 1:2 n=3). Similar results were obtained using patient derived xenograft (PDX) AML cells. In contrast to Kasumi-1 AML cells, specific killing of patient-derived PDX cells could be documented with lower E:T ratios and lower prodrug concentrations (pivot point from killing to proliferation at 0,05 nM and E:T of 1:5) We also started to analyze the anti-leukemic effect in vivo. Luciferase-expressing CD200+/CD123+ AML PDX cells were injected into NSG mice. On day +15, PBMC from a healthy individual were transplanted, followed by additional applications of the antibodies on days +16, +18, +21, +23, +25 & +29. Tumor burden was analyzed by bioluminescence imaging (log10 fold change [P/sec] 2 weeks after PBMC injection: Control 1,9; treated -0,4; group size = 3). In conclusion the combination of anti CD200 and anti CD123 as prodrugs of an on-target activating trispecific T-cell engager kills AML cells in vitro and in vivo and has the potential to eliminate AML LSC while minimizing the risk for severe on-target off-leukemia toxicity. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

:Assembled for Use: Indigenous Compilation and the Archives of Early Native American Literatures

:<i>Assembled for Use: Indigenous Compilation and the Archives of Early Native American Literatures</i>

Changes in Deep Ocean Contribute to a “See‐Sawing” Gulf Stream Path

AbstractThis study demonstrates that a decrease of the water‐mass density below 1,000 m has led to a pattern of see‐saw shift in the Gulf Stream (GS) position between 74 and 50°W in longitude during 1993–2017, with the New England Seamounts as the pivot point. The GS moved northward in the upstream region and shifted southward in the downstream. Our empirical orthogonal function analyses of satellite altimeter data demonstrate that the second mode (EOF2) represents changes in the GS strength and therefore can be used as an index for the Atlantic Meridional Overturning Circulation. Decreasing water density below 1,000 m is also the principal mechanism driving the weakening of the GS.