Self-assembled monolayers with biospecific affinity for lactate dehydrogenase for the electroenzymatic oxidation of lactate

Surface modified gold electrodes with high biospecific affinity for NAD(H)-dependent lactate dehydrogenase have been prepared by covalent attachment of several traizine dyes to stepwise functionalized mixed alkanethiol self-assembled monolayers. The biospecific affinity of such ligand-anchored monolayers to bind submonolayer amounts of enzyme was demonstrated from the course of the protein adsorption events monitored by surface plasmon resonance. Electroenzymatic activity measurements of lactate dehydrogenase modified surfaces for the reaction of lactate oxidation, carried out `ex situ¿ at different stages of protein layer growth, allowed the optimization of the preparative procedure to yield reproducible enzymatic electrodes with a low amount of unspecifically bound protein. A short adsorption time, as well as a high concentration of enzyme in the solution used for protein layer growth, led to lactate dehydrogenase-modified gold electrode surfaces with a high electroenzymatic activity arising mainly from biospecifically bound species. The lowest amount of unspecifically adsorbed protein was found for ligand-anchored monolayers prepared from mixed alkanethiol underlayers with an excess of positively charged groups. The lack of electroenzymatic activity shown by lactate dehydrogenase modified electrodes in the absence of soluble coenzyme (NAD+) indicates that none of the investigated ligand-anchored monolayers could provide an efficient electronic pathway from the metal to the active site of the enzyme. Therefore, the monolayers acted just as an anchoring system for lactate dehydrogenase

TTCPR: a PMC receiver for TTC

Abstract The TTCPR receiver is a mezzanine card intended for use in distributing TTC information to Data Acquisition and Trigger Crates in the ATLAS Prototype Integration activities. An original prototype run of these ~cards was built for testbeam and integration studies, implemented in both the PMC and PCI form factors, using the TTCrx chips from the previous manufacture. When the new TTCrx chips became available, the TTCPR was redesigned to take advantage of the availability and enhanced features of the new TTCRX(1), and a run of 20 PMC cards was manufactured, and has since been used in integration studies and the testbeam. The TTCPR uses the AMCC 5933(2) to manage the PCI port, an Altera 10K30A(3) to provide all the logic so that the functionality may be easily altered, and provides a 4K deep FIFO to retain TTC data for subsequent DMA through the PCI port. In addition to DMA's which are mastered by the Add On logic, communication through PCI is accomplished via mailboxes, interrupts, and the pass-through feature of the 5933. An interface to the I2C bus of the TTCRX is provided so that internal registers may be accessed, and the card supports reinitialization of the TTCRX from PCI. Software has been developed to support operation of the TTCPR under both LynxOS and Linux. I. History of the TTCPR The TTCPR was developed in response to a need for TTC(4) information in the Data Acquisition from TileCal Modules in the ATLAS Test Beam. Specifically, it was desired to have EventID, Bunch Counter, and Trigger Type available from TTC in the data records. It was useful to have the TTC information available to processors in the Data Acquisition crates through PCI ports, and to have the data transferred to the processor's address space via an externally mastered DMA. Accordingly, the TTCPR was designed as a mezzanine card in the PMC form factor. The original cards utilized the older nonradhard version of the TTCRX, because the new radhard version was not available at that time. When it became clear that the new TTCRX would be available soon and also that it would not be possible to obtain any more of the older TTCRX chips, the TTCPR was redesigned, and enhancements were added to take advantage of the features of the new TTCRX. This new TTCPR was produced and has been used successfully in data acquisition at the ATLAS Test Beam. The card has also been implemented in the PCI form factor. The TTCPR in the PMC version is shown in II. Architecture of the TTCPR A block diagram of the TTCPR is shown i

Construction of the Soudan 2 detector

Progress in the construction of the Soudan 2 nucleon decay detector which is being built at the Soudan iron mine in Minnesota is discussed. The expected event rate and characteristics of low energy neutrino events, muon events, multiple muon events, and other cosmic ray phenomena are discussed

Experimental study of the reactions e(+)e(-)→e(+)e(-) and e(+)e(-)→γγ at 29 GeV

This is the publisher's version, also available electronically from http://journals.aps.org/prd/abstract/10.1103/PhysRevD.34.3286.This paper reports measurements of the differential cross sections for the reactions e(+)e(-)→e(+)e(-) (Bhabha scattering) and e(+)e(-)→γγ (γ-pair production). The reactions are studied at a center-of-mass energy of 29 GeV and in the polar-angular region ‖costheta‖154 GeV and Λ->220 GeV for Bhabha scattering, and Λ+>59 GeV and Λ->59 GeV for γ-pair production

A bispecific diabody directed against prostate-specific membrane antigen and CD3 induces T-cell mediated lysis of prostate cancer cells

BACKGROUND: Although cancer of the prostate is one of the most commonly diagnosed cancers in men, no curative treatment currently exists after its progression beyond resectable boundaries. Therefore, new agents for targeted treatment strategies are needed. Cross-linking of tumor antigens with T-cell associated antigens by bispecific monoclonal antibodies have been shown to increase antigen-specific cytotoxicity in T-cells. Since the prostate-specific membrane antigen (PSMA) represents an excellent tumor target, immunotherapy with bispecific diabodies could be a promising novel treatment option for prostate cancer. METHODS: A heterodimeric diabody specific for human PSMA and the T-cell antigen CD3 was constructed from the DNA of anti-CD3 and anti-PSMA single chain Fv fragments (scFv). It was expressed in E. coli using a vector containing a bicistronic operon for co-secretion of the hybrid scFv V_HCD3-V_LPSMA and V_HPSMA-V_LCD3. The resulting PSMAxCD3 diabody was purified from the periplasmic extract by immobilized metal affinity chromatography (IMAC). The binding properties were tested on PSMA-expressing prostate cancer cells and PSMA-negative cell lines as well as on Jurkat cells by flow cytometry. For in vitro functional analysis, a cell viability test (WST) was used. For in vivo evaluation the diabody was applied together with human peripheral blood lymphocytes (PBL) in a C4-2 xenograft-SCID mouse model. RESULTS: By Blue Native gel electrophoresis, it could be shown that the PSMAxCD3 diabody is mainly a tetramer. Specific binding both to CD3-expressing Jurkat cells and PSMA-expressing C4-2 cells was shown by flow cytometry. In vitro, the diabody proved to be a potent agent for retargeting PBL to lyze C4-2 prostate cancer cells. Treatment of SCID mice inoculated with C4-2 tumor xenografts with the diabody and PBL efficiently inhibited tumor growth. CONCLUSIONS: The PSMAxCD3 diabody bears the potential for facilitating immunotherapy of prostate cancer and for the elimination of minimal residual disease

The longitude problem from the 1700s to today: An international and general education physics course

For instructors wishing to use physics as part of an international or general education course, the framework for a course based on the “longitude problem” from the 1700s is described. The longitude problem is teeming with basic principles of physics and astronomy, which makes it ideal for a non-science-major-based college-level course. This paper summarizes the longitude problem in the context of conceptual physics and astronomy and outlines an appropriate curriculum. Specifics on teaching such a course in London, as part of an international studies program, are discussed

Uses and Abuses of Effective Lagrangians

Motivated by past and recent analyses we critically re-examine the use of effective lagrangians in the literature to constrain new physics and to determine the `physics reach' of future experiments. We demonstrate that many calculations, such as those involving anomalous trilinear gauge-boson couplings, either considerably overestimate loop-induced effects, or give ambiguous answers. The source of these problems is the use of cutoffs to evaluate the size of such operators in loop diagrams. In contrast to other critics of these loop estimates, we prove that the inclusion of nonlinearly-realized gauge invariance into the low-energy lagrangian is irrelevant to this conclusion. We use an explicit example using known multi-Higgs physics above the weak scale to underline these points. We show how to draw conclusions regarding the nature of the unknown high-energy physics without making reference to low-energy cutoffs.Comment: 36 page

Full deflection profile calculation and Young’s modulus optimisation for engineered high performance materials

New engineered materials have critical applications in different fields in medicine, engineering and technology but their enhanced mechanical performances are significantly affected by the microstructural design and the sintering process used in their manufacture. This work introduces (i) a methodology for the calculation of the full deflection profile from video recordings of bending tests, (ii) an optimisation algorithm for the characterisation of Young’s modulus, (iii) a quantification of the effects of optical distortions and (iv) a comparison with other standard tests. The results presented in this paper show the capabilities of this procedure to evaluate the Young’s modulus of highly stiff materials with greater accuracy than previously possible with bending tests, by employing all the available information from the video recording of the tests. This methodology extends to this class of materials the possibility to evaluate both the elastic modulus and the tensile strength with a single mechanical test, without the need for other experimental tools