Rapid characterization of binding specificity and cross-reactivity of antibodies using recombinant human protein arrays.

Antibodies are routinely used as research tools, in diagnostic assays and increasingly as therapeutics. Ideally, these applications require antibodies with high sensitivity and specificity; however, many commercially available antibodies are limited in their use as they cross-react with non-related proteins. Here we describe a novel method to characterize antibody specificity. Six commercially available monoclonal and polyclonal antibodies were screened on high-density protein arrays comprising of ~10,000 recombinant human proteins (Imagenes). Two of the six antibodies examined; anti-pICln and anti-GAPDH, bound exclusively to their target antigen and showed no cross-reactivity with non-related proteins. However, four of the antibodies, anti-HSP90, anti-HSA, anti-bFGF and anti-Ro52, showed strong cross-reactivity with other proteins on the array. Antibody-antigen interactions were readily confirmed using Western immunoblotting. In addition, the redundant nature of the protein array used, enabled us to define the epitopic region within HSP90 of the anti-HSP90 antibody, and identify possible shared epitopes in cross-reacting proteins. In conclusion, high-density protein array technology is a fast and effective means for determining the specificity of antibodies and can be used to further improve the accuracy of antibody applications

Vincristine, doxorubicin and dexamethasone (VAD) administered as rapid intravenous infusion for first-line treatment in untreated multiple myeloma

We examined the feasibility of achieving a rapid response in patients with previously untreated multiple myeloma by administering vincristine 0.4 mR and doxorubicin 9 mg/m2 as a rapid intravenous infusion for 4 d together with intermittent high-dose dexamethasone 40 mg (VAD) for remission induction treatment in patients who were scheduled to receive high-dose therapy. 139 patients (86 male, 53 female; median age 53 years, range 32-65 years; Durie and Salmon stage IIA: 42, IIB: one, IIIA: 89, IIIB: seven) were included in a prospective multicentre study in which VAD was administered as remission induction treatment and was followed by intensified treatment. The response was evaluated according to the criteria of the Eastern Cooperative Oncology Group (ECOG). The results of treatment were evaluable in 134 patients. Five patients died before evaluation. 86 patients (62%) achieved a partial response (PR) and seven patients (5%) achieved a complete response (CR), which equates to a response rate of 67%. The main side-effect was mild neurotoxicity, which was observed in 18% of the patients. Fever or infections were reported in 27% of the patients. VAD administered as an outpatient regimen, based on rapid intravenous infusion, is an effective induction regimen for untreated myeloma with a 67% response rate and acceptable toxicity

Investigation of the fluid flow during the recoating process in additive manufacturing

Purpose This paper aims to explore the fluid flow in the stereolithography process during the recoating step. The understanding of the flow dynamics can be used as an input for an active control of the resin surface height map. The recoating over a rectangular cavity has been considered to investigate the influence of the cavity depth on the resin surface height map. Design/methodology/approach Two-dimensional numerical simulations have been used to obtain the flow characteristics as function of the cavity depth. An experimental setup, which mimics the recoating process in the stereolithography process, was used to verify the results of simulations and to test the suitability of the 2D model. The surface height profile along the centreline was measured by a confocal chromatic distance sensor and compared to the 2D numerical results. Findings By means of computational fluid dynamics (CFD) simulation, the flow in the cavity and the free-surface behaviour of the resin was explained for different cavity depths and confirmed by experiments. Research limitations/implications The study is focused only on the cavity depth variation to show feasibility and suitability of the presented CFD model and the proposed analytical expression to estimate the layer thickness. Practical implications The proposed approach can serve as a tool for designing the closed-loop control for the recoating system in the next generation of stereolithography equipment. Originality/value In the present work, the fluid flow behaviour, a source of significant imperfection in the recoating process, has been investigated during the recoating step over a rectangular cavit

Real-time feedback controlled conversion in vat photopolymerization of ceramics: a proof of principle

Technical ceramics for high-performance applications can be additively manufactured using vat photopolymerization technology. This technology faces two main challenges: increasing ceramic product size and improving product quality. The integration of process control strategies into AM equipment is expected to play a key role in tackling these challenges. This work demonstrates the feasibility of real-time and in-situ feedback control of the light-initiated polymerization reaction that lies at the core of vat photopolymerization technology. To prove the principle, a single-layer experimental setup was developed in which the degree of conversion was measured by infrared spectroscopy. Experimental data obtained from this setup was used to develop a control-oriented process model and identify its parameters. A material perturbation was applied by adding an inhibitor and the case with and without feedback control were compared. The results show that the feedback controller successfully compensated for the material perturbation and reached the same final conversion value as the unperturbed case. This result can be considered a fundamental step towards additive manufacturing of defect-free ceramic parts using in-line process control

A classification scheme for AM control strategies: the AM V-model

The current lack of consistent additive manufacturing (AM) part quality gives rise to the development of novel process monitoring and control strategies [1]. The identification of these strategies can be facilitated by formulating a classification scheme to position development efforts. This work proposes a classification scheme that was developed in the context of vat photopolymerization [2], but is expected to be applicable to a wide range of AM technologies since many commonalities exist in the multi-level control characteristics

A Trade-Off Analysis of Recoating Methods for Vat Photopolymerization of Ceramics

Technical ceramic parts can be produced by curing ceramic-filled resins in the vat photopolymerization (stereolithography) process. Scaling up to larger ceramic product sizes and higher product quality calls for the integration of more sensing, actuation and closed-loop control solutions while taking a systems engineering approach. This paper gives a comprehensive overview of methods to deposit a layer of (ceramic-filled) resin, better known as recoating. The aim of this work is to perform a trade-off analysis of recoating methods to enable the selection of the method that best meets the requirements for scaling up the printable object size in the ceramic vat photopolymerization process.Mechanical Engineerin

A feasibility study on process monitoring and control in vat photopolymerization of ceramics

Vat photopolymerization is a prominent additive manufacturing technology for the fabrication of near-net shape ceramic parts. To serve the high tech industry's needs, additive manufacturing equipment has to scale up to larger product sizes and higher, repeatable product quality. This motivates the integration of more process monitoring and control solutions into the equipment. Hence, this paper reviews the state of the art in process modelling, sensing, actuation and control for ceramic vat photopolymerization. The aim is to analyze the feasibility of potential real-time control schemes for the vat photopolymerization process. A comparison of time scales related to physical phenomena in vat photopolymerization, sampling rates of sensors, and response times of actuators, shows that feasibility of real-time control is governed by sensor sampling rates. With the current state of sensor technology, real-time control is only feasible in mask projection systems. Alternatively, one can resort to layer-to-layer control schemes