Significance of tungsten disulfide on the mechanical and machining characteristics of phosphor bronze metal matrix composite

The phosphor bronze (PB) is widely preferred in various engineering applications due to its high strength, toughness, fine grain size, low coefficient of friction, and better corrosion resistance. The present work is to investigate the effect of tungsten disulfide (WS2) solid lubricant particle reinforcement in the phosphor bronze metal matrix composite (PBMC) through the mechanical and machining characteristics. The different variant of the composite is fabricated using stir casting technique by varying the volume percentage of WS2 particle from 0% to10%. The prepared PBMC samples are subjected to mechanical and machining (boring and high-speed turning) characterizations. The hardness (Brinell hardness) and flexural strength of the composites are examined as per the ASTM standard. The surface roughness (Ra) of the PBMC sample is analyzed through the boring and high-speed turning operations by varying the spindle speed, feed rate, and depth of cut. The scanning electron microscope (SEM) is employed to confirm the uniform dispersion of the reinforcement particle through the microstructural analysis. The presence of WS2 particles and other ingredients is ensured by X-ray diffraction analysis in the composites. The influence of WS2 reinforcement particles on tool life is analyzed on the PBMC4 (PBMC with 8% WS2) with the predefined machining parameters in the high-speed turning operation. The increase in WS2 particle (0–10%) improves the hardness (11.85%) and flexural strength in PBMC4 as compared to PBMC1 (PBMC with 0% WS2). At a higher spindle speed (1200 r/min), the Ra is reduced in PBMC1 as compared to 900 r/min, whereas the rest of the PBMC sample show higher surface irregularity at 1200 r/min.

Follicular Lymphoma Organoids for Investigating the Tumor Microenvironment

Background: Current in vitro lymphoma models, including three-dimensional organoids, generally contain exclusively neoplastic lymphocytes and require artificial reconstitution to recapitulate the tumor microenvironment (TME). The co-culture of syngeneic tumor-infiltrating lymphocytes (TILs) alongside endogenous primary malignant lymphocytes could be useful for modeling complex interactions in the TME, and for immunological maneuvers and therapies relying on TILs. However, such conditions for maintaining lymphomas in their syngeneic TME as a cohesive unit have remained elusive. Methods: We adapted an air-liquid interface (ALI) method that we previously described (Neal JT et al 2019 Cell) for propagating patient-derived organoids (PDOs) from primary human follicular lymphomas. Surgically excised lymphoma samples were tested for the ability to maintain lymphoma cell viability in vitro using a lymph node organoid technique. Lymph nodes containing lymphoma cells (and in one case, a PBMC sample including circulating lymphoma cells) were processed into a single cell suspension and frozen until use. Samples were thawed and prepared into immune organoids (see figure). We assessed cell composition by flow cytometry on day 7, and in a subset of samples, up to 21 days post-thaw. Results: A total of 6 patients were profiled for PDO formation, PDO composition and stability, and PDO longevity. 4 of 6 samples showed good cell viability at day 7 post-culture and in a subset of samples, up to 21 days post-culture. Cell composition was well-maintained over time, with presence of lymphoma cells (CD19+ CD10+ CD5-) easily detectable and maintenance of supporting cells of the lymph node such as T follicular helper cells (CD3+ CD4+ CXCR5+ PD-1+) and non-B, non-T cells. Supporting lymph node cells were not detected in the PBMC sample, suggesting the cell composition is related to the initial composition and not due to differentiation in vitro. Genotyping, gene expression phenotyping, and T-cell/B-cell receptor profiling data will be presented at the meeting, including accuracy of PDOs for preserving the original spectrum of these indices. Conclusions: Propagation of PDOs of primary lymphomas with endogenous immune stroma is feasible and maintains cohesive elements of the TME. This system should allow immunoncology investigations within the TME and to facilitate personalized immunotherapy testing. Fig 1: Human lymphoma organoid cultures as a model to study tumor microenvironments and immune responses in vitro. (A) Experimental schema for preparing lymphoma organoids from tumor explants. In an adapted workflow optimized for ex vivo culture of human tonsillar germinal centers (Wagar L et al, submitted), we subject cryopreserved FL samples to organoid culture. (B) An example of follicular lymphoma organoid reorganization in vitro after four days in culture. (C) Total cell viability in FL organoids for up to 21 days in culture. Six samples were tested. (D) Frequency of major cell types in FL samples after organoid culture. Although there is variation among donors' samples, an individual's cell composition is well maintained for at least 14 days in most organoids. Figure 1 Disclosures Khodadoust: Corvus Pharmaceuticals: Research Funding. Davis:Vir Biotechnology: Consultancy, Equity Ownership, Honoraria; PACT Bio: Consultancy, Equity Ownership, Honoraria; Adicet Inc: Consultancy, Equity Ownership, Honoraria; Chuga Pharmabody: Consultancy, Honoraria; Amgen: Consultancy, Research Funding; Atreca: Consultancy, Equity Ownership, Honoraria; Juno: Consultancy, Equity Ownership, Honoraria. Alizadeh:Pfizer: Research Funding; Chugai: Consultancy; Celgene: Consultancy; Gilead: Consultancy; Pharmacyclics: Consultancy; Janssen: Consultancy; Genentech: Consultancy; Roche: Consultancy.

A Model for the Binding of Fluorescently Labeled Anti-Human CD4 Monoclonal Antibodies to CD4 Receptors on Human Lymphocytes

The CD4 glycoprotein is a component of the T cell receptor complex which plays an important role in the human immune response. This manuscript describes the measurement and modeling of the binding of fluorescently labeled anti-human CD4 monoclonal antibodies (mAb; SK3 clone) to CD4 receptors on the surface of human peripheral blood mononuclear cells (PBMC). CD4 mAb fluorescein isothiocyanate (FITC) and CD4 mAb allophycoerythrin (APC) conjugates were obtained from commercial sources. Four binding conditions were performed, each with the same PBMC sample and different CD4 mAb conjugate. Each binding condition consisted of the PBMC sample incubated for 30 min in labeling solutions containing progressively larger concentrations of the CD4 mAb-label conjugate. After the incubation period, the cells were re-suspended in PBS-based buffer and analyzed using a flow cytometer to measure the mean fluorescence intensity (MFI) of the labeled cell populations. A model was developed to estimate the equilibrium concentration of bound CD4 mAb-label conjugates to CD4 receptors on PBMC. A set of parameters was obtained from the best fit of the model to the measured MFI data and the known number of CD4 receptors on PBMC surface. Divalent and monovalent binding had to be invoked for the APC and FITC CD4 mAb conjugates, respectively. This suggests that the mAb binding depends on the size of the label, which has significant implications for quantitative flow cytometry. The study supports the National Institute of Standards and Technology program to develop quantitative flow cytometry measurements.