Physics-Based Modeling for Determining Transient Current Flow in Multi-Layer Pcb Pi Designs

A physics-based modeling methodology for determining the transient current flow path in multi-layer PI designs is given in this paper using a commercial board with a complicated structure as an example. Board structure analysis is done first to provide a physical basis of post-layout analytical and equivalent circuit modeling. A match of the PDN impedance between commercial tool simulation, post-layout analytical calculation, and the physics-based equivalent circuit modeling was achieved to support the model for the transient simulation. By analyzing the current response in all the vias, a clear representation of transient current flow across all via segments can be given layer-by-layer. The maximum current density in vertical vias can also be extracted in this process, providing a reference for preventing transient overcurrent design

System Level PDN Impedance Optimization Utilizing the Zeros of the Decoupling Capacitors

System-Level Power Distribution Network (PDN) Impedance Optimization Utilizing the Zeros of the Decoupling Capacitors (Decaps) is Discussed in This Paper. an Example of a Practical PDN Application is Proposed to Validate the Poles and Zeros Algorithm (P&Z) Presented. the System-Level PDN is with the Printed Circuit Board (PCB), Package (PKG), and Chip, as Well as the Low-Frequency Decaps on the PCB and the On-PKG Decoupling Capacitors. the PDN Optimization Results Are Compared with Those from the Genetic Algorithm (GA) to Show the Reasonableness and Validity of the P&Z Algorithm

Exploring the impact of group work and mentoring for multiple heritage children's self-esteem, well-being and behaviour

Findings are reported from a study of an innovative Multiple Heritage Service in Sheffield (UK) which provides, inter alia, individual mentoring for young people and school-based group sessions on cultural heritage, dealing with racism and enhancing well-being. Groupwork, undertaken between November 2005 and December 2006, was evaluated by a before/after design with 43 children aged from eight to fifteen attending five different groups (response rate 77 per cent), using three well-established and validated measures. There were improvements on the Rosenberg Self-esteem Scale from 31.415 to 33.024 (p =0.005) with more improvement among younger children and boys (p=0.004 and p=0.001); and well-being as measured by the GHQ12 improved from 1.460 to 0.8378 (p=0.111) with more improvement among older children (p=0.026). On the third measure, of problem behaviour (the Strengths and Difficulties Questionnaire) there was an improvement from 12.4 to 12.1 (p=0.716) but there was no improvement at all for girls. Mentoring was evaluated by telephone interviews between June and October 2006 with 14 mothers whose children had just completed, or were nearing completion of, mentoring (response rate 70 per cent). Overall the mothers’ evaluations were highly positive: two-thirds commended the service on the positive impact on their children’s well-being and happiness (including all the mothers of daughters); a half reported positive impacts on identity; mothers commended the positive role model effect same-sex mentors had on their children’s behaviour; but only a third said mentoring had boosted their children’s self-esteem

Regulation of Proliferation by a Mitochondrial Potassium Channel in Pancreatic Ductal Adenocarcinoma Cells

Previous results link the mitochondrial potassium channel Kv1.3 (mitoKv1.3) to the regulation of apoptosis. By synthesizing new, mitochondria-targeted derivatives (PAPTP and PCARBTP) of PAP-1, a specific membrane-permeant Kv1.3 inhibitor, we have recently provided evidence that both drugs acting on mitoKv1.3 are able to induce apoptosis and reduce tumor growth in vivo without affecting healthy tissues and cells. In the present article, by exploiting these new drugs, we addressed the question whether mitoKv1.3 contributes to the regulation of cell proliferation as well. When used at low concentrations, which do not compromise cell survival, both drugs slightly increased the percentage of cells in S phase while decreased the population at G0/G1 stage of cells from two different pancreatic ductal adenocarcinoma lines. Our data suggest that the observed modulation is related to ROS levels within the cells, opening the way to link mitochondrial ion channel function to downstream, ROS-related signaling events that might be important for cell cycle progression

A Methodical Approach for Pcb Pdn Decoupling Minimizing overdesign with Genetic Algorithm Optimization

An optimization routine is applied for the decoupling capacitor placement on Power Distribution Networks to identify the limit beyond which the placement of additional decaps is no longer effective, thus leading to wasting layout area and components, and to a cost increase. A specific test example from a real design is used together with the required target impedance and frequency band of interest for the PDN design. The effectiveness of the decap placement while selecting different layers of the stack-up, and while moving the upper limit of the PDN design band is analyzed. Such analysis leads to helpful insights based on the progression of the input impedance during the optimization process, and to develop useful guidelines for avoiding over-design of the PDN