Integer Linear Programming-Based Bit-Level Optimization for High-Speed FIR Decimation Filter Architectures

Analog-to-digital converters based on sigma-delta modulation have shown promising performance, with steadily increasing bandwidth. However, associated with the increasing bandwidth is an increasing modulator sampling rate, which becomes costly to decimate in the digital domain. Several architectures exist for the digital decimation filter, and among the more common and efficient are polyphase decomposed finite-length impulse response (FIR) filter structures. In this paper, we consider such filters implemented with partial product generation for the multiplications, and carry-save adders to merge the partial products. The focus is on the efficient pipelined reduction of the partial products, which is done using a bit-level optimization algorithm for the tree design. However, the method is not limited only to filter design, but may also be used in other applications where high-speed reduction of partial products is required. The presentation of the reduction method is carried out through a comparison between the main architectural choices for FIR filters: the direct-form and transposed direct-form structures. For the direct-form structure, usage of symmetry adders for linear-phase filters is investigated, and a new scheme utilizing partial symmetry adders is introduced. The optimization results are complemented with energy dissipation and cell area estimations for a 90 nm CMOS process.     

Synthesis and structural characterization of Tm:Lu2O3 nanocrystals. An approach towards new laser ceramics

Nanocrystals of Tm³⁺ Thulium doped cubic sesquioxides, Tm:Lu₂O₃, with a maximum size around 30 nm have been synthesized by a modified Pechini sol-gel method. The calcination temperature for the synthesis is 1073 K. Electron microscopy was used to analyze the presence of aggregates, and the type of boundary between the nanocrystals. The linear coefficient of thermal expansion for these nanocrystals has been determined to be around 7.5 × 10⁻⁶ K⁻¹. The growth of the nanocrystals has been studied in terms of temperature and time. Nanocrystals start to grow at temperatures around 1267 K. Finally, the grain growth activation energy of this material has been evaluated to be 76 kJ/mol, indicating a diffusion growth mechanism. Linear thermal expansion of prepared nanocrystals is ≈7.5 × 10⁻⁶ K⁻¹.     

Speciation and ecological risk of toxic elements in estuarine sediments affected by multiple anthropogenic contributions (Guadiana saltmarshes, SW Iberian Peninsula): I. Surficial sediments

Recent studies have demonstrated that the Guadiana Estuary contains metal concentrations in excess of background values. Therefore, this work aims to document the potential environmental hazards associated with the availability of these metals in this environment of high ecological value. Mineralogical analysis shows that the sediments are composed mainly of quartz, albite, and clay minerals (illite, smectite, kaolinite, and vermiculite) along with several small, reactive compounds (including soluble sulphated salts, Fe-Mn oxyhydroxides, organic matter, and pyrite) capable of retaining metals, which can be subsequently released, causing environmental degradation. BCR sequential extraction shows that As, Cd, Cu, Mn, Pb, and Zn present mobile fractions with respect to the total metal content (41, 100, 57, 53, 70, and 69%, respectively) in any of the described reactive phases (F1 + F2 + F3).Calculated environmental risk indices demonstrate moderate to considerable ecological risk for almost the entire estuary, associated mainly with acid mine drainage from the nearby Iberian Pyrite Belt. In addition, the indices highlight several zones of extremely high risk, which are related to industrial and urban dumps in the vicinity of the estuary and to heavy traffic on the international bridge.     

Presenting features and prognosis in 72 patients with multiple myeloma who were younger than 40 years

The purpose of this study was to analyse the presenting clinical and laboratory features and the outcome of 72 patients with multiple myeloma (MM) who were younger than 40 years. The records of all Mayo Clinic patients with MM younger than 40 years who were seen between 1 January 1956 and 31 December 1992 were reviewed. Survival was measured from the date when treatment was required to the date of last follow-up or death. The frequency of MM in patients younger than 40 and 30 years in 3278 Mayo Clinic patients was 2.2% and 0.3%, respectively. The main presenting clinical features were bone pain (66%), fatigue (26%), extramedullary plasmacytomas (19%) and bacterial infection (11%). Renal function impairment (creatinine level > or = 177 micromol/l) and hypercalcaemia (serum calcium value > or = 2.75 mmol/l) occurred in 29% and 30% of patients, respectively. Among the 57 patients evaluable for response the objective response rate was 54%. 14/35 patients treated with a single alkylating agent achieved an objective response, whereas 17/22 patients given combination chemotherapy had an objective response (P=0.013). However, this higher response rate did not result in a significantly longer survival. The median survival for the 72 patients was 54 months. Patients with good prognostic features (normal renal function or low beta 2-microglobulin level) had a median survival of 8 years. The actuarial survival at 5 and 10 years after initiation of therapy was 43% and 13%, respectively. In summary, survival in very young patients with myeloma is longer than that observed in series of patients of all ages, especially in those with good prognostic factors.     

A simple test device for electrometers

Electrometers used in dosimetric instruments need to be checked regularly in order to measure and maintain the prescribed dose to the patient. This paper describes the function of a simple but accurate test device for electrometers. A number of electrometers have been tested and compared with calibrations performed by the Swedish Standard Dosimetry Laboratory (SSDL). The device can be used to test current, resistance, voltage and charge measurements. The charge can be conducted to the electrometer in different ways, and the input resistance of the electrometer can also be determined. The calibration factors obtained by the device are in good agreement with results obtained from calibrations at the SSDL.     

The interference of pharmaceuticals with endogenous and xenobiotic metabolizing enzymes in carp liver: an in-vitro study

The interactions of fibrate (clofibrate, fenofibrate, bezafibrate, gemfibrozil), antiinflammatory (ibuprofen, diclofenac, naproxen, ketoprofen), and anti-depressive (fluoxetine,fluvoxamine, paroxetine) drugs with CYP catalyzed pathways (CYP1A, CYP3A-, CYP2K-, and CYP2M-like) and Phase II activities (UDP-glucuronosyltransferases and sulfotransferases), involved in both xenobiotic and endogenous metabolism in fish, were investigated in-vitro by incubating carp liver subcellular fractions in the presence of the substrate and the selected drug. Anti-depressive drugs were strong inhibitors of CYP1A (92-94% inhibition), CYP3A-like (69-80% inhibition), and CYP2K-like (36-69% inhibition) catalyzed activities, while antiinflammatory drugs were potent CYP2M-like inhibitors (32-74% inhibition). Among the lipid regulators, gemfibrozil strongly inhibited CYP2M-catalyzed activity (91% inhibition) and other CYP isoforms (CYP1A and CYP3A-like). Additionally, glucuronidation of naphthol and testosterone were targeted by antiinflammatory drugs, and to a lesser extent, by fibrate drugs (48-78% inhibition). No significant alteration on sulfotransferase activities was observed, apart from a minor inhibitory effect of clofibrate, gemfibrozil, and fluoxetine on the sulfation of estradiol. Overall, gemfibrozil, diclofenac, and the three anti-depressive drugs appear to be the pharmaceuticals with the highest potential to interfere with fish metabolic systems.     

Plastic Deformation of Hydroxyapatites and Its Application to Joining

A plastic deformation process was demonstrated to self-join hydroxyapatite (HA), fabricating pore-free joints at 1275°C at a strain rate of 10⁻⁵ s⁻¹. To determine optimum joining conditions, high-temperature compressive deformation of HA was investigated for strain rates between 5 × 10⁻⁶ and 10⁻⁴ s⁻¹ at temperatures 1175–1275°C. X-ray diffraction revealed primarily the HA phase with the presence of tri- and tetra-calcium phosphate phases. Steady-state flow stresses were 0.6–45 MPa and increased with increasing strain rates. Stress exponents of ≈1 indicated a viscous diffusion-controlled deformation mechanism with an activation energy of ≈354±36 kJ/mol. Absence of cavitation and grain shape changes was consistent with grain boundary sliding.     

Hepatic levels of metal and metallothioneins in two commercial fish species of the Northern Iberian shelf

Metal levels (Cd, Pb, Hg, Cr, Fe, Cu, Zn) together with metallothioneins (MTs) were determined in the liver of two commercial fish species collected along the Northern Iberian coast. The four-spotted megrim (Lepidorhumbos boscii) and the pouting (Trisopterus luscus) were selected as representative species of the middle/outer (200-500 m) and inner shelf (70-120 m), respectively. Metal pollution in the middle/outer shelf was mostly detected in the Asturias and Basque Country areas, whereas in the inner shelf, pollution was widely spread along the coast. Significantly high levels of Pb, Cd, Cr and Hg were detected in T. luscus from different sampling sites and associated to anthropogenic pressure. MTs were induced in fish that had higher amounts of Zn, Cd, Cr and Hg in their livers, supporting the use of MT as a biomarker of metal exposure. The study supports the usefulness of the selected fish species as sentinel organisms for future biomonitoring studies.