High throughput VLSI DSP using replicated finite rings

This paper discusses strategies for implementing DSP systems using residue replication. The theory, recently introduced by two of the authors, uses formal polynomial ring mappings, from binary representations, to direct product ring implementation of integer processing arrays. The mapping produces completely independent computational arrays each computing over the same ring. This paper describes an architecture and processing array to implement, and take advantage of, the special computational ring structures that result from the mapping. A brief review of the theory and mapping techniques, is followed by the discussion of the architecture and VLSI design of an efficient inner product processing array using Fermat Primes.     

Interactions of histaminergic and serotonergic neurons in the hypothalamic regulation of prolactin and ACTH secretion

Serotonergic and histaminergic neuronal systems are both involved in mediation of the stress-induced release of the pituitary hormones prolactin (PRL) and ACTH. We investigated the possibility of an interaction between serotonin (5-HT) and histamine (HA) in regulation of PRL and ACTH secretion in conscious male rats. Animals were pretreated systemically with antagonists to 5-HT1, 5-HT2 or 5-HT3 receptors prior to intracerebroventricular (icv) administration of HA. The 5-HT1 + 2 receptor antagonist methysergide prevented and the 5-HT2 receptor antagonist LY 53857 attenuated the HA-induced PRL release while the 5-HT3 receptor antagonist ondansetron had no effect on this response. None of the three 5-HT receptor antagonists affected the ACTH response to HA. Specific blockade of HA synthesis by alpha-fluoromethylhistidine or blockade of postsynaptic HA receptors by icv infusion of the H1 receptor antagonist mepyramine or the H2 receptor antagonist cimetidine inhibited the PRL response to 5-HT or to the 5-HT precursor 5-hydroxytryptophan (5- HTP) given in combination with the 5-HT reuptake inhibitor fluoxetine (Flx). Blockade of the histaminergic system had no effect on the ACTH response to serotonergic stimulation. The H3 receptors are inhibitory HA receptors. Systemic pretreatment with the H3 receptor agonist R(alpha)methylhistamine, or the H3 receptor antagonist thioperamide had no effect on the hormone response to activation of the serotonergic system by 5-HTP plus Flx. We conclude that the serotonergic and histaminergic neuronal systems interact in their stimulation of PRL secretion, but not in their stimulation of ACTH secretion. This interaction involves serotonergic 5-HT1 and 5-HT2 receptors and histaminergic H1 and H2 receptors. Furthermore, the previously observed inhibitory effect of the H3 receptor agonist R(alpha)methylhistamine on stress-induced PRL and ACTH release seems not to be exerted by activation of presynaptic H3 receptors located on serotonergic neurons but rather on histaminergic neurons.     

Expression of a mannose/fucose membrane lectin on human dendritic cells

Dendritic cells (CD) are the most efficient antigen presenting cells for T lymphocytes. CD1a+ CD14- CD with high antigen-presenting capacities can now be obtained easily from adherent peripheral blood monocytes by culture in the presence of granulocyte/macrophage colony-stimulating factor and interleukin-4 (Sallusto et al., J. Exp. Med. 1994. 179: 1109). Human macrophages express a membrane lectin, or sugar-specific receptor, which specifically mediates the binding and endocytosis of mannose- and fucose-terminated glycoproteins and is involved in the phagocytosis of pathogens. A similar lectin activity was sought on cultured human DC using flow cytometry and confocal microscopy to detect binding and internalization of fluoresceinated neoglycoproteins [bovine serum albumin (BSA) substituted with sugar residues]. Several neoglycoproteins, especially alpha-L-fucosyl-, alpha-D-mannosyl-, N,N'-di-acetyl-beta-chitobiosyl- and beta-D-glucosyl-BSA, were endocytosed by cultured human CD1a+ DC as well as by CD1a- CD14- cells which were also obtained in the culture. Fuc-BSA and Man-BSA had the same number of binding sites (1.7 x 10(6)/cell) on CD1a+ DC, and bound with an affinity constant close to 10(7) 1/mol. Inhibition experiments indicated that these two neoglycoproteins bound to the same membrane lectin. CD1a+ and CD1a- cells were both labeled by an antiserum specific for the human macrophage mannose receptor. The membrane lectin specific for mannose and fucose that is evidenced in these experiments on cultured DC may be similar to the macrophage membrane lectin or may share functional and structural properties with it.     

Error floor of MSK modulation in a mobile-radio channel with twoindependently fading paths

We investigate the error probability bit error rate (BER) of minimum shift keying (MSK) modulation with differential detection in a two-path fading channel without noise (error floor). We develop a new method for the computation of the BER: we show that errors occur if the phasors of the instantaneous impulse response fall into certain regions of the complex plane; then we average over the statistics of the phasors to arrive at the mean BER. With this method, we derive analytical expressions for the BER for arbitrary amplitude statistics of the paths. For the special case of two Rayleigh-fading paths with small delay, we find that the BER is proportional to the square of the mean delay spread (normalized to the bit length) if we sample between the two pulses. This proves the qualitative behavior of previous estimates, but our results allow also a more exact quantitative formulation. The quadratic dependence of the BER on the delay spread breaks down if we have one Rayleigh-fading and one Rician-fading path. We find that the bit combinations 1-11 and -11-1 do not lead to errors in the two-path model. However, additional Monte Carlo simulations show that these bit combinations do lead to errors in a three-path model     

Laparoscopic surgery of adrenal glands: indications and limits

Over the last four years it has been demonstrated that laparoscopy can be used successfully for adrenalectomy, providing certain advantages over conventional open surgery. The aim of this study was to determine the indications for laparoscopic approach in adrenal surgery. From June 1994 to June 1996 laparoscopic transabdominal flank approaches were proposed in patients with a unilateral 8 cm or less, non-malignant tumors of the adrenal gland. For tumors under 4 cm in diameter only secreting tumors were removed. Among 77 patients requiring ablation of the adrenal gland, 50 (65%) underwent a laparoscopic procedure: 29 Conn adenomas, 10 Cushing adenomas, 6 Pheochromocytomas, 4 incidentalomas. One patient had Cushing's disease and underwent bilateral resection. Mean tumor size was 26 mm (7-75 mm). Malignancy was demonstrated in 2 tumors: one cortisone secreting tumor and one leiomyosarcoma. Conversion was required in 4 cases (8%). Mean operative time for unilateral adrenalectomies was 147 minutes (50-300'). There were no deaths. Morbidity included: one hemorrhage via the trocar orifice requiring reoperation, one infarction of the spleen which regressed spontaneously, one parietal hematoma, and one case of phebitis of the lower limb. The endocrinopathy was successfully cured in all patients with secreting tumors. The 27 other patients underwent open adrenalectomy. Laparoscopic approach was not proposed due to suspected malignancy in 13 cases, previous surgery in 8 cases and multiple, bilateral and/or extra adrenal tumors in 6 cases. Laparoscopic approach to the adrenal gland is the procedure of choice in patients with Conn adenomas, Cushing adenomas and in most cases of pheochromocytomas. It is not indicated for malignant and large tumor (> 8 cm). Currently two-thirds of our patients requiring and adrenalectomy are operated laparoscopically.     

Idiopathic epilepsy in the dog

The authors present a brief history of the development of the Ilizarov external fixator, and the classic uses associated with it. A preliminary study of 3 patients using 56 frames is presented. The Ilizarov external fixator is successfully used in these cases in place of traditional fixation.     

Large signal analysis of the LCC-type parallel resonant converterusing discrete time domain modeling

A discrete time domain model for the LCC-type parallel resonant power converter has been derived. This model has been used to predict the large signal behavior of the power converter. The peak component stresses and the dynamic response of the key state variables, as obtained from the large signal analysis, using PRO-MATLAB software are plotted. SPICE results are included to verify the analytical results. Experimental results are also presented to verify the theory     

Uniaxial tensile response of microfibre reinforced cement composites

Microfibre reinforced cement composites reinforced with high volume fractions of carbon, steel and polypropylene fibres were tested in uniaxial tension. Composites investigated included those with only one type of fibre (mono-fibre composites) and those with two or more types of fibres (hybrid-fibre composites) in the same mix. Considerable strengthening, toughening and stiffening of the host matrix due to microfibre reinforcement were observed. In the hybrid-fibre composites, different fibres appear to act as additive phases; i.e., they maintain their individual reinforcing capabilities. The composites were also impact tested in uniaxial tension using a newly designed instrumented impact machine. When compared with static test results, considerable sensitivity to stress rate was noted; composites were found to be stronger and tougher under impact and the improvements were more pronounced at higher fibre volume fractions. The potential of these composites for use in thin sheet products and other similar applications is recognized, and the need for continued research is stressed.     

Solar Oven, design, and its field testing in West Lombok regency, Indonesia

Design of four Solar Ovens, box type, are described. All materials used in the latest design are locally available. This is one of the basis of considerations in designing beside simplicity and long life time. Solar oven of the latest design yielded 160°C without load and 50 units have been field tested in West Lombok regency since July 1995. Its cooking ability, materials used, size and shape, social acceptance and further activities are described.