Phase locked loop-based clock synthesizer for reconfigurable analog-to-digital converters

Analog Integrated Circuits and Signal Processing - This paper presents the complete design of a phase locked loop-based clock synthesizer for reconfigurable analog-to-digital converters. The...     

Design and evaluation of a mobile smart home interactive system with elderly users in Brazil

Personal and Ubiquitous Computing - This article presents a study concerning the evaluation of a smart home control system for elderly people with a sample of 10 users in a city in the interior of...     

In situ TEM observations of fracture in nanolaminated metallic thin films

Fracture of single crystal nanolaminated thin films has been investigated through in situ straining of cross-sectional samples of Cu/Ni nanolaminates grown on Cu (001) single crystal substrates. The earlest stages of deformation exhibits a confined layer slip mechanism. With continued straining, unstable fracture occurs creating a mixed-mode crack that propagates across the nanolaminate, roughly perpendicular to the interfaces. Eventually, stable crack growth with intense plastic deformation ahead of the crack tip occurs over many bilayers in the direction of crack growth. Simultaneously, plasticity was seen to spread only 1 or 2 bilayer distances normal to the crack, creating an extremely localized plastic zone. Transmission electron microscopic (TEM) examination after the test did not reveal the presence of dislocations in the crack wake, except where severe crack deflection was observed. By comparison, the plastic zone size in the substrate was greater by several of orders of magnitude.     

Insect chitinases: molecular biology and potential use as biopesticides

Chitin, an insoluble structural polysaccharide that occurs in the exoskeletal and gut linings of insects, is a metabolic target of selective pest control agents. One potential biopesticide is the insect molting enzyme, chitinase, which degrades chitin to low molecular weight, soluble and insoluble oligosaccharides. For several years, our laboratories have been characterizing this enzyme and its gene. Most recently, we have been developing chitinase for use as a biopesticide to control insect and also fungal pests. Chitinases have been isolated from the tobacco hornworm, Manduca sexta, and several other insect species, and some of their chemical, physical, and kinetic properties have been determined. Also, cDNA and genomic clones for the chitinase from the hornworm have been isolated and characterized. Transgenic plants that express hornworm chitinase constitutively have been generated and found to exhibit host plant resistance. A transformed entomopathogenic virus that produces the enzyme displayed enhanced insecticidal activity. Chitinase also potentiated the efficacy of the toxin from the microbial insecticide, Bacillus thuringiensis. Insect chitinase and its gene are now available for biopesticidal applications in integrated pest management programs. Current knowledge regarding the molecular biology and biopesticidal action of insect and several other types of chitinases is described in this mini-review.     

Plasma GABA in children and adolescents with mood, behavior, and comorbid mood and behavior disorders: a preliminary study

Plasma GABA concentrations (pGABA) were measured in 115 inpatients (aged 7-17) with child psychiatric disorders. Group mean pGABAs were compared for 38 patients with mood disorders only (MOOD), 29 with behavior disorders only (BEH), 48 with comorbid mood and behavior disorders (MOOD + BEH), and 14 normal controls (CON, aged 14-17). The BEH group was characterized by (a) high mean pGABAs (157 vs. 133 pmol/ml), (b) lower mean pGABAs in BEH subjects who had been receiving pharmacotherapy with SSRIs or other medications (p < 0.026), and (c) decreased pGABA with increasing age (p = 0.019). These features were not found in controls or in groups of patients with mood disorders (MOOD or MOOD + BEH). Elevated mean pGABA in the BEH group appeared specifically in patients with comorbid CD and ADHD, not in patients with ADHD or CD alone (p = 0.004). No patient in BEH (or CON) had pGABA below 100 pmol/ml, but low pGABAs were found in 15% of MOOD patients (who had no behavior disorder) and in 16% of MOOD + BEH patients. Pharmacotherapy did not change pGABAs in the MOOD or the MOOD + BEH groups. No pGABA differences were found among the anxiety disorders, either alone or with mood or behavior comorbidity. The finding that plasma GABA levels are elevated in nonmedicated behavior disorders that present in the absence of mood disorders, and appear to lower following medication treatments, merits increased attention to the pharmacological study of nonaffective behavior disorders.     

Tumor necrosis factor-alpha-induced apoptosis in a human keratinocyte cell line (HaCaT) is counteracted by transforming growth factor-alpha

Pulmonary surfactant is a complex mixture of lipids and proteins that functions to keep alveoli from collapsing at the end of expiration. Dipalmitoylphosphatidylcholine has been identified as the most important component for lowering surface tension at the air-liquid interface. Hydrophobic surfactant apoproteins, SP-B and SP-C, play essential roles in the biophysical functions of the surfactant phospholipids. Hydrophilic surfactant apoproteins (SP-A and SP-D) that are members of C-type lectin superfamily, interact with phospholipids and glycolipids and modulate host defense functions in the lung. SP-A also plays an important role in regulating phospholipid homeostasis in the alveolar spaces. Recent advances in genetics and molecular biology have clarified the structure-function relationship of surfactant apoproteins.     

Capacity results for the discrete memoryless network

A discrete memoryless network (DMN) is a memoryless multiterminal channel with discrete inputs and outputs. A sequence of inner bounds to the DMN capacity region is derived by using code trees. Capacity expressions are given for three classes of DMNs: (1) a single-letter expression for a class with a common output, (2) a two-letter expression for a binary-symmetric broadcast channel (BC) with partial feedback, and (3) a finite-letter expression for push-to-talk DMNs. The first result is a consequence of a new capacity outer bound for common output DMNs. The third result demonstrates that the common practice of using a time-sharing random variable does not include all time-sharing possibilities, namely, time sharing of channels. Several techniques for improving the bounds are developed: (1) causally conditioned entropy and directed information simplify the inner bounds, (2) code trellises serve as simple code trees, (3) superposition coding and binning with code trees improves rates. Numerical computations show that the last technique enlarges the best known rate regions for a multiple-access channel (MAC) and a BC, both with feedback. In addition to the rate bounds, a sequence of inner bounds to the DMN reliability function is derived. A numerical example for a two-way channel illustrates the behavior of the error exponents.     

Effect of ethanol on platelet phospholipase A2

Platelet aggregation is known to be inhibited by ethanol, and this has been suggested to be one of the attenuating effects of ethanol in cardiovascular disease. Recent studies have implicated an inhibition of phospholipase A₂ induced arachidonic acid release, since the production of prostanoids that are formed from arachidonic acid and are involved in the aggregation process has been shown to be diminished by ethanol. Phospholipase A₂ is found in platelets in both a cytosolic form, from where it may translocate to the plasma membrane to release arachidonic acid, and in a secretory form which is released extracellularly upon activition. In the present study, the effect of ethanol on the secretion of phospholipase A₂ and on its activity was determined. It was found that ethanol inhibited trast, the activity of the cytosolic form of phospholipase A₂ was inhibited by ethanol.