Time--frequency analysis of biosignals

The wavelet transform has a powerful time-frequency analysis and signal-coding tool suitable for use in the manipulation of complex nonstationary signals. This article provides an overview of the emerging role of wavelet-transform analysis in biomedical signal processing and analysis. It also provides a brief overview of the theory of the transform in its two distinct and very different forms: continuous and discrete. In conclusion, it has been shown that the wavelet transform is a flexible time-frequency decomposition tool that can form the basis of useful signal analysis, and coding schemes. It is envisaged that the future will see further application of the wavelet transform to biomedical signal analysis, as the emerging technologies based on them are honed for practical purposes.     

Basics and applications of charge pumping in submicron MOSFETs© 1997 IEEE. Reprinted, with permission, from Proc. 1997 21st International Conference on Microelectronics, Nis, Yugoslavia, 14–17 September 1997, Vol. 2, pp. 581–589.

In this paper, a review is made of the principles and the various applications of charge pumping in submicron MOSFETs. The use of the technique for the analysis of MOSFET degradation, energy, and both lateral and vertical spatial profiling of the interface traps, is discussed. The role and detection of so-called geometric components is illustrated, and the recently discovered ability of the technique to characterise single interface traps in submicron MOSFETs is demonstrated. Finally, the application of charge pumping in other devices, such as SOI-MOSFETs, EEPROM-cells and power transistors is briefly indicated.     

Radiation spectra of laser-driven quantum relativistic electrons

A procedure to calculate the radiation spectrum emitted by an arbitrarily prepared Dirac wave packet is developed. It is based on the Dirac charge current and classical electrodynamic theory. Apart from giving absolute intensity values, it is exact in terms of relativistic retardation effects and angular dependence. We employ a laser driven free electron to demonstrate the advantages of our method as compared to traditional ones that merely rely on the Fourier transform of the dipole operator's expectation value. Classical reference calculations confirm the results obtained for the low-frequency part of the spectrum, especially in terms of the observed red-shifts, which clearly deviate from non-relativistic calculations. In the high-frequency part of the spectrum, we note appreciable deviations to the purely classical calculations which may be linked to quantum averaging effects.     

Negative Mood, Self-Focused Attention, and the Experience of Physical Symptoms: The Joint Impact Hypothesis.

A joint impact hypothesis on symptom experience is introduced that specifies the role of negative mood and self-focus, which have been considered independently in previous research. Accordingly, negative affect only promotes symptom experience when people simultaneously focus their attention on the self. One correlational study and 4 experiments supported this prediction: Only negative mood combined with self-focus facilitated the experience (see the self-reports in Studies 1, 2a, & 2b) and the accessibility (lexical decisions, Stroop task in Studies 3 & 4) of physical symptoms, whereas neither positive mood nor negative mood without self-focus did. Furthermore, the joint impact of negative mood and self-focused attention on momentary symptom experience remained significant after controlling for the influence of dispositional symptom reporting and neuroticism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does depression interfere with effort mobilization? Effects of dysphoria and task difficulty on cardiovascular response.

On the basis of predictions of the mood-behavior model (G. H. E. Gendolla, 2000) and motivational intensity theory (J. W. Brehm & E. A. Self, 1989), the authors conducted 2 studies that critically tested the common assumption that dysphoria is associated with a motivational deficit. Dysphoric and nondysphoric undergraduates performed a cognitive task that was either easy or difficult. Effort intensity (i.e., resource mobilization) was assessed as performance-related cardiovascular reactivity. In support of the authors' predictions and in contrast to the popular view of a general motivational deficit, both studies found a crossover interaction between dysphoria and task difficulty: In the difficult condition, nondysphoric participants indeed showed stronger systolic blood pressure reactivity than dysphoric participants. But in the easy condition, dysphoric participants showed stronger systolic reactivity than nondysphoric participants. The findings are discussed with respect to motivational deficits in depression and possible underlying mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modified micro–macro thermo-mechanical modelling of ceramic ball grid array packages

The ceramic ball grid array (CBGA) packages are typically used for high I/O count area array assemblies. As the package size is large, the distance to neutral point is also high resulting in a large thermal deformation mismatch between the CBGA package and the printed circuit board (PCB). In order to cope with this problem, a special solder joint connection is used. As CBGA assemblies are used for high pin count assemblies, a full 3D thermo-mechanical modelling of an assembly to an FR4 board is not possible anymore. Therefore, a modified micro–macro methodology is proposed where only the critical solder joint is modelled in detail, while the other connections are replaced by equivalent connections. For several CBGA configurations, simulation results are correlated to thermal cycling test results. Finally, a parameter sensitivity study shows that the PCB properties have a significant influence on the solder joint reliability.     

Exploring Prostate Cancer Genome Reveals Simultaneous Losses of PTEN,FAS and PAPSS2 in Patients with PSA Recurrence after Radical Prostatectomy

The multifocal nature of prostate cancer (PCa) creates a challenge to patients’ outcome prediction and their clinical management. An approach that scrutinizes every cancer focus is needed in order to generate a comprehensive evaluation of the disease, and by correlating to patients’ clinico-pathological information, specific prognostic biomarker can be identified. Our study utilized the Affymetrix SNP 6.0 Genome-wide assay to investigate forty-three fresh frozen PCa tissue foci from twenty-three patients. With a long clinical follow-up period that ranged from 2.0–9.7 (mean 5.4) years, copy number variation (CNV) data was evaluated for association with patients’ PSA status during follow-up. From our results, the loss of unique genes on 10q23.31 and 10q23.2–10q23.31 were identified to be significantly associated to PSA recurrence (p < 0.05). The implication of PTEN and FAS loss (10q23.31) support previous reports due to their critical roles in prostate carcinogenesis. Furthermore, we hypothesize that the PAPSS2 gene (10q23.2–10q23.31) may be functionally relevant in post-operative PSA recurrence because of its reported role in androgen biosynthesis. It is suggestive that the loss of the susceptible region on chromosome 10q, which implicates PTEN, FAS and PAPSS2 may serve as genetic predictors of PSA recurrence after radical prostatectomy.     

Hydroxide-Bonding Strength Measurements for Space-Based Optical Missions

Optical contacting has long been used in interferometric experiments both on the ground and in space-based missions. Its optical clarity makes it an ideal method to joint materials of comparable coefficients of thermal expansion. Once the two pieces are bonded, they are commonly broken through thermal or vibrational cycling. Unfortunately, larger bond areas are needed for the bond to form appreciable strength, which often excludes it from being used in complex optical bench designs in space-based missions. Another method, known colloquially as hydroxide bonding, has shown to have superior strength to optical contacting using smaller bonding areas. In addition, the hydroxide bonding process will work on several materials that do not need to meet the stringent polishing requirements of optical contacting. These properties make hydroxide bonding suitable for complex optical bench designs that can withstand the large accelerations encountered during launch conditions for use in space-based missions. In this paper, we report on shear strength measurements of BK7-to-BK7 hydroxide bonds as well as present new results for BK7-to-silicon carbide and BK7-to-Super Invar bonds.     

Reaction Kinetics and Intermediate Determination of Solid Acid Catalysed Liquid-phase Hydrolysis Reactions: A Real-time in situ ATR FT-IR Study

The appearance of catalyst–reactant interactions observed in on-line ATR FT-IR spectra of Nafion/silica catalysed esterification and etherification reactions of 1-octanol was investigated. It was assessed by variation of catalyst and solvent that the catalyst–reactant band is a result of the reaction of silica with 1-octanol, yields Si–O–R functionalities. Based on off-line TPD-MS and TGA characterisation of the used solid catalyst powder, the formation of Si–O–R linkages on the SiO₂ surface was confirmed. This demonstrates conclusively that in specific liquid-phase reactions, on-line analysis of intermediate species adsorbed on heterogeneous catalysts is possible. Using on-line particle analyzers, it was assessed that the absorptions were not the result of severe attrition of the catalyst particles in the course of the reaction, but apparently the result of apolar interactions of the particles with the diamond crystal.