Tyrosine Phosphorylation of C-ErbB-2 Is Regulated by the Cellular Form of Prostatic Acid Phosphatase in Human Prostate Cancer Cells

Human prostatic acid phosphatase (PAcP) is a prostate epithelium- specific differentiation antigen. In prostate carcinomas, the cellular PAcP is decreased. We investigated its functional role in these cells. Several lines of evidence support the hypothesis that cellular PAcP functions as a neutral protein-tyrosine phosphatase and is involved in regulating prostate cell growth. In this study, we identify its in vivo substrate. Our results demonstrated that, in different human prostate cancer cell lines, the phosphotyrosine (Tyr(P)) level of a 185-kDa phosphoprotein (pp185) inversely correlates with the cellular activity of PAcP. On SDS-PAGE, this pp185 comigrates with the c-ErbB-2 oncoprotein. Immunodepletion experiments revealed that c-ErbB-2 protein is the major pp185 in cells. Results from subclones of LNCaP cells indicated the lower the cellular PAcP activity, the higher the Tyr(P) levels of c-ErbB-2. This inverse correlation was further observed in PAcP cDNA-transfected cells. In clone 33 LNCaP cells, L-(+)- tartrate suppresses the cellular PAcP activity and causes an elevated Tyr(P) level of c-ErbB-2 protein. Epidermal growth factor stimulates the proliferation of LNCaP cells, which concurs with a decreased cellular PAcP activity as well as an increased Tyr(P) level of c-ErbB-2. Biochemically, PAcP dephosphorylates c-ErbB-2 at pH 7.0. The results thus suggest that cellular PAcP down-regulates prostate cell growth by dephosphorylating Tyr(P) on c-ErbB-2 oncoprotein in those cells

A smoothing Newton method based on the generalized Fischer-Burmeister function for MCPs

[[abstract]]We present a smooth approximation for the generalized Fischer-Burmeister function where the 2-norm in the FB function is relaxed to a general p-norm (p > 1), and establish some favorable properties for it, for example, the Jacobian consistency. With the smoothing function, we transform the mixed complementarity problem (MCP) into solving a sequence of smooth system of equations.

Encoding specific associative memories

The overarching aim of this thesis was to examine the nature of what is encoded during simple associative learning and configural learning. The experiments used rats as subjects and appetitive conditioning designs to assess the validity of two assumptions that are prevalent within standard accounts of learning in animals. First, animals simply represent the patterns of stimulation that are currently present in the environment. Second, that although the conditions that prevailed during the acquisition of associative knowledge have a marked effect on the strength of the resulting association, the association itself is "blind" with respect to the origin of this influence. The results presented in Chapters 2 and 3 undermine the first assumption by showing that associatively provoked (Experiments 1-3) and short-term traces (Experiments 4-6) can be assimilated into configural representations. The results presented in Chapter 4, from studies involving control rats (Experiment 7) and rats with lesions of the hippocampus (Experiment 8), indicate that animals ordinarily represent the nature of the stimulus trace (immediate or short-term) in the associative structures that are acquired during conditioning. The findings from Chapter 4 are inconsistent with the view that associative learning is blind with respect to the nature of the encoding conditions. Taken together, the novel results presented in this thesis reveal that what is encoded during simple associative learning and configural learning is much richer than has hitherto been realized

The Magnitude of Switching Costs for Corporate Antivirus Software Switching Decision

Today’s businesses environment is forcing companies to become increasingly more efficient in applying Internet technology to conduct transactions. AS the possibility of infection by computer virus is much greater now than ever before, businesses search for appropriate corporate antivirus software to safeguard their computer systems. This paper considers corporate antivirus software switching as one of the major security selection problem and proposes possible avenues for software switching decision and management. In conceptual model, we draw upon switching costs where transaction costs, learning costs, and artificial costs were examined as main costs for software switching decision. Our findings shown only two out of three types of switching costs have influence over corporate antivirus software switching decisions. Despite the existence of switching costs, businesses continue to repeat software switching because the perceived risks of security threats are much greater than the switching cost itself. Furthermore, we examine various approaches to the cost of switching and then propose an index map to evaluate switching decision. Five sets of propositions are advanced to help guide this research

Mediated configural learning in rats

Three experiments investigated mediated configural learning in male rats. In Experiment 1, after exposure to audio-visual compounds AX and BY, rats received trials where X was paired with shock, and Y was not. The idea that conditioning with X enables the evoked configural representation of AX to be linked to shock received support from the facts that while AX provoked more fear than BX, there was no difference between BY and AY. Similarly, Experiment 2 showed that after exposure to AX and BY, separate pairings of X and Y with shock resulted in more fear to AX and BY than AY and BX. In Experiment 3, rats in group consistent received separate exposures to A and X in Context C, and B and Y in D, while those in group inconsistent received A and X (and B and Y) in both C and D. After rats had received shocks in both C and D, rats in group consistent showed more fear to AX and BY than to BX and AY, but this was not the case in group inconsistent. These results indicate that configural representations, formed either by presenting auditory and visual stimuli as parts of a compound or in a shared context, are subject to a process of mediated learning

Adult morphology and redescription of Lestidiops indopacificus (Ege, 1953), with comments on the features of related species (Teleostei, Aulopiformes, Paralepididae)

Two specimens representing the first known adults of Lestidiops indopacificus (Ege, 1953) are reported and described from Taiwan, and the validity and generic assignment of this species are confirmed. The origin of the pelvic fin directly below the dorsal-fin base shows that L. indopacificus belongs to the L. mirabilis species complex. It can be separated from its congeners by the position of the nostrils above the posterior end of the maxilla, the light body color with unevenly distributed melanophores in adults, and a distinct combination of meristic values and other morphological characteristics. New geographic records are reported for the two other current members of this species complex, L. mirabilis (Ege, 1933) and L. extremus (Ege, 1953). The diagnostic features that separate these three very similar species are discussed

On Scalable Service Function Chaining with O(1) Flowtable Entries

The emergence of Network Function Virtualization (NFV) enables flexible and agile service function chaining in a Software Defined Network (SDN). While this virtualization technology efficiently offers customization capability, it however comes with a cost of consuming precious TCAM resources. Due to this, the number of service chains that an SDN can support is limited by the flowtable size of a switch. To break this limitation, this paper presents CRT-Chain, a service chain forwarding protocol that requires only constant flowtable entries, regardless of the number of service chain requests. The core of CRT-Chain is an encoding mechanism that leverages Chinese Remainder Theorem (CRT) to compress the forwarding information into small labels. A switch does not need to insert forwarding rules for every service chain request, but only needs to conduct very simple modular arithmetic to extract the forwarding rules directly from CRT-Chain's labels attached in the header. We further incorporate prime reuse and path segmentation in CRT-Chain to reduce the header size and, hence, save bandwidth consumption. Our evaluation results show that, when a chain consists of no more than 5 functions, CRT-Chain actually generates a header smaller than the legacy 32-bit header defined in IETF. By enabling prime reuse and segmentation, CRT-Chain further reduces the total signaling overhead to a level lower than the conventional scheme, showing that CRT-Chain not only enables scalable flowtable-free chaining but also improves network efficiency

Conditioning with spatio-temporal patterns: Constraining the contribution of the hippocampus to configural learning

The conditions under which the hippocampus contributes to learning about spatio-temporal configural patterns are not fully established. The aim of Experiments 1–4 was to investigate the impact of hippocampal lesions on learning about where or when a reinforcer would be delivered. In each experiment, the rats received exposure to an identical set of patterns (i.e., spotted + morning, checked + morning, spotted + afternoon and checked + afternoon); and the contexts (Experiment 1), times of day (Experiment 2), or their configuration (Experiments 3 and 4) signalled whether or not a reinforcer would be delivered. The fact that hippocampal damage did not disrupt the formation of simple or configural associations involving spatio-temporal patterns is surprising, and suggests that the contribution of the hippocampus is restricted to mediated learning (or updating) involving spatio-temporal configurations

Validation of the Action Research Arm Test using item response theory in patients after stroke

Objective: To validate the unidimensionality of the Action Research Arm Test (ARAT) using Mokken analysis and to examine whether scores of the ARAT can be transformed into interval scores using Rasch analysis. Subjects and methods: A total of 351 patients with stroke were recruited from 5 rehabilitation departments located in 4 regions of Taiwan. The 19-item ARAT was administered to all the subjects by a physical therapist. The data were analysed using item response theory by non-parametric Mokken analysis followed by Rasch analysis. Results: The results supported a unidimensional scale of the 19-item ARAT by Mokken analysis, with the scalability coefficient H = 0.95. Except for the item pinch ball bearing 3rd finger and thumb'', the remaining 18 items have a consistently hierarchical order along the upper extremity function's continuum. In contrast, the Rasch analysis, with a stepwise deletion of misfit items, showed that only 4 items (grasp ball'', grasp block 5 cm(3)'', grasp block 2.5 cm(3)'', and grip tube 1 cm(3)'') fit the Rasch rating scale model's expectations. Conclusion: Our findings indicated that the 19-item ARAT constituted a unidimensional construct measuring upper extremity function in stroke patients. However, the results did not support the premise that the raw sum scores of the ARAT can be transformed into interval Rasch scores. Thus, the raw sum scores of the ARAT can provide information only about order of patients on their upper extremity functional abilities, but not represent each patient's exact functioning