Selection of metal-cutting machines in operational design by means of PLM systems

© 2017, Allerton Press, Inc.A method is proposed for the selection of metal-cutting machines in the design of technological operations using Teamcenter and UNIGRAPHICS NX software

Errors in shaping by a planetary mechanism

© 2017, Allerton Press, Inc. The proposed planetary reaming method permits discontinuous turning in which the cutting edge moves relative to the cutting surfaces. As a result, individual sections of the cutting zone move successfully in and out of the machining zone. Discontinuous turning is free of the deficiencies of continuous turning

Identifying the primary rigidity axes in the elastic system of a metal-cutting machine

© 2016, Allerton Press, Inc.A computer experiment based on CAE systems may be used to determine the primary rigidity axes in the supporting systems of metal-cutting machines. The formulation of the models, the experimental method, and the applicability of the method are considered

Trochoidal slot milling

© 2017, Allerton Press, Inc. Parameter specification in the trochoidal machining of a slot of constant width is considered. A formula is proposed for the displacement increment of the shaping circle as a function of the cutting depth

Precision of surfaces machined on a lathe with geometric errors

© 2017, Allerton Press, Inc.The precision attained in the shape and mutual position of cylindrical surfaces after machining may be assessed by means of a mathematical model. The effectiveness of the model is confirmed in practice

Antibody Repertoires in Humanized NOD-scid-IL2Rγnull Mice and Human B Cells Reveals Human-Like Diversification and Tolerance Checkpoints in the Mouse

Immunodeficient mice reconstituted with human hematopoietic stem cells enable the in vivo study of human hematopoiesis. In particular, NOD-scid-IL2Rγnull engrafted mice have been shown to have reasonable levels of T and B cell repopulation and can mount T-cell dependent responses; however, antigen-specific B-cell responses in this model are generally poor. We explored whether developmental defects in the immunoglobulin gene repertoire might be partly responsible for the low level of antibody responses in this model. Roche 454 sequencing was used to obtain over 685,000 reads from cDNA encoding immunoglobulin heavy (IGH) and light (IGK and IGL) genes isolated from immature, naïve, or total splenic B cells in engrafted NOD-scid-IL2Rγnull mice, and compared with over 940,000 reads from peripheral B cells of two healthy volunteers. We find that while naïve B-cell repertoires in humanized mice are chiefly indistinguishable from those in human blood B cells, and display highly correlated patterns of immunoglobulin gene segment use, the complementarity-determining region H3 (CDR-H3) repertoires are nevertheless extremely diverse and are specific for each individual. Despite this diversity, preferential DH-JH pairings repeatedly occur within the CDR-H3 interval that are strikingly similar across all repertoires examined, implying a genetic constraint imposed on repertoire generation. Moreover, CDR-H3 length, charged amino-acid content, and hydropathy are indistinguishable between humans and humanized mice, with no evidence of global autoimmune signatures. Importantly, however, a statistically greater usage of the inherently autoreactive IGHV4-34 and IGKV4-1 genes was observed in the newly formed immature B cells relative to naïve B or total splenic B cells in the humanized mice, a finding consistent with the deletion of autoreactive B cells in humans. Overall, our results provide evidence that key features of the primary repertoire are shaped by genetic factors intrinsic to human B cells and are principally unaltered by differences between mouse and human stromal microenvironments

Surface Microrelief of Shafts after Machining by Mills with Replaceable Inserts

© 2019, Allerton Press, Inc. Abstract: The height of the surface microrelief is determined for complex components in turning by a disk mill with a replaceable polyhedral insert. The influence of the cutting conditions and tool geometry on the microrelief is investigated