Persistence and partitioning of eight selected pharmaceuticals in the aquatic environment: Laboratory photolysis, biodegradation, and sorption experiments

We selected eight pharmaceuticals with relatively high potential ecological risk and high consumption—namely, acetaminophen, atenolol, carbamazepine, ibuprofen, ifenprodil, indomethacin, mefenamic acid, and propranolol—and conducted laboratory experiments to examine the persistence and partitioning of these compounds in the aquatic environment. In the results of batch sunlight photolysis experiments, three out of eight pharmaceuticals—propranolol, indomethacin, and ifenprodil—were relatively easily photodegraded (i.e., half-life < 24 h), whereas the other five pharmaceuticals were relatively stable against sunlight. The results of batch biodegradation experiments using river water suggested relatively slow biodegradation (i.e., half-life > 24 h) for all eight pharmaceuticals, but the rate constant was dependent on sampling site and time. Batch sorption experiments were also conducted to determine the sorption coefficients to river sediments and a model soil sample. The determined coefficients (K_d values) were much higher for three amines (atenolol, ifenprodil, and propranolol) than for neutral compounds or carboxylic acids; the K_d values of the amines were comparable to those of a four-ring polycyclic aromatic hydrocarbon (PAH) pyrene. The coefficients were also higher for sediment/soil with higher organic content, and the organic carbon-based sorption coefficient (log K_oc) showed a poor linear correlation with the octanol-water distribution coefficient (log D_ow) at neutral pH. These results suggest other sorption mechanisms—such as electrochemical affinity, in addition to hydrophobic interaction—play an important role in sorption to sediment/soil at neutral pH.     

Hemodynamic characterization of YM435, a novel dopamine DA1 receptor agonist, in anesthetized dogs

In previous studies on experimental renal failure, hypertrophy of cardiomyocytes, diminished capillarization, and increased intercapillary distances had been observed, abnormalities that will expose the heart to reduced ischemia tolerance. It has not been established, however, whether such structural alterations are unique for the heart (eg, as a consequence of left ventricular hypertrophy) or are demonstrable in other tissues as well. Clarification of this point is important to test hypotheses on some potential mechanisms for cardiac undercapillarization. To address this issue further, we compared capillary length density (by stereologic techniques) in perfusion-fixed skeletal muscle (m. psoas) and hearts of subtotally nephrectomized (SNX) rats with moderate renal failure to those in sham-operated pair-fed controls. The duration of renal failure was 8 weeks. SNX rats had significantly higher mean systolic blood pressure (128 mm Hg v 109 mm Hg), serum creatinine, and urea levels. Despite pair feeding, the mean body weight was significantly lower in the SNX rats (409 g v 471 g), but the left ventricular weight to body weight ratio tended to be higher than in the sham-operated controls (2.39 mg/g v 2.13 mg/g). In the heart, myocyte mean cross-sectional area (675 +/- 112 microm2 v 545 +/- 111 microm2) and volume density of nonvascular interstitial tissue (3.47 +/- 1.04 v 1.33 +/- 0.22) were significantly higher in the SNX rats than in the controls. In parallel, myocardial capillary length density was significantly reduced after subtotal nephrectomy (3,036 +/- 535 mm/mm3 v 3,916 +/- 615 mm/mm3). In contrast, in skeletal muscle, myocyte cross-sectional area (3,109 +/- 783 microm2 v 3,042 +/- 639 microm2), capillary length density (718 +/- 248 mm/mm3 v 717 +/- 184 mm/mm3), and three-dimensional capillary fiber ratio (2.10 +/- 0.26 v 2.13 +/- 0.4) were similar in SNX and control rats. These data document a selective defect of capillarization in the heart of animals with moderate renal failure, pointing to tissue-specific abnormalities of cardiac capillarogenesis.     

Validation of temporal BRDFs of paddy fields estimated from MODIS reflectance data

The effect of the bidirectional reflectance distribution function (BRDF) is one of the most important factors in correcting and validating the reflectance obtained from remotely sensed data. While the importance of BRDF has become widely recognized, bidirectional reflectance factor (BRF) data measured for correction and validation are insufficient because of the technical difficulty of the measurement. The primary objective of the present research is to estimate BRDF effects from Moderate Resolution Imaging Spectroradiometer (MODIS) data. Temporal ground-based BRDFs of rice paddy fields were estimated from ground measurements conducted in June and August 2002. MODIS-derived BRDFs obtained from MODIS reflectance data and ground-based BRDFs were estimated using the reciprocal form of the RossThick and LiSparse (RossThick-LiSparse-R) kernels, a semiempirical BRDF model adopted for the operational MODIS BRDF product. The MODIS-derived band 1 (620-680 nm) and band 2 (841-876 nm) BRDFs were compared with the ground-based BRDFs corresponding to the same waveband, respectively. The comparison results demonstrate that BRDFs of paddy fields change in accordance with paddy growth and that MODIS-derived BRDFs are closely related to ground-based BRDFs in most of the cases. It was also revealed that MODIS-derived BRDFs can be estimated to a high degree of accuracy when MODIS data necessary for the estimation are available.     

Observation of short fatigue crack-growth process in SiC-fiber-reinforced Ti-15-3 alloy composite

The microscopic fatigue damage characteristics and short fatigue crack growth of an unnotched SiC(SCS-6) fiber-reinforced Ti-15-3 alloy composite were investigated in tension-tension fatigue tests (R = 0.1) carried out at room temperature for applied maximum stress of 450, 670, and 880 MPa.In situ observation of the damage-evolution process was done using optical and scanning laser microscopies, which were attached in the fatigue machine. The first damage for the composite started from a cracking of the reaction layer followed by fiber fracture. The matrix cracking initiated near the broken fiber when the microhardness of the matrix just to the side of the fracture fiber reached ≈6 GPa, and the number of cycles for the initiation of this cracking decreased with the increase of applied stress. The slope of the relation of surface crack growth lengthvs number of cycles fell into two characteristic stages; in the first stage, the rate was lower than the second stage and accelerated. The surface crack growth rate,d(2c)/dN,vs surface crack length relation also fell into two stages (stages I and II). With the increase in surface crack length, the crack-growth rate,d(2c)/dN, decreased in stage I and increased in stage II. The transition from stage I to stage II occurred due to the fracture of fibers located around the first fractured fiber. It was concluded that the fatigue crack growth resistance of the composite in the short-crack region was controlled by the fiber fracture and matrix work hardening near the fractured fiber. When the fiber fracture occurred, the surface crack growth rate was accelerated and became faster than that of the monolithic matrix.     

Regulation of early cholesterol biosynthesis in rat liver: effects of sterols, bile acids, lovastatin, and BM 15.766 on 3-hydroxy-3-methylglutaryl coenzyme A synthase and acetoacetyl coenzyme A thiolase activities

BACKGROUND: Sclerosing peritonitis (SP) is a rare but serious complication of peritoneal dialysis (PD). Small-bowel obstruction (SBO) due to encapsulation, dense adhesions, or mural fibrous is characteristic, often associated with peritonitis. The aim of the study was to determine the incidence, clinical features, effect of duration of dialysis, and other possible aetiological factors in severe SP. METHODS: All dialysis units in Australia were surveyed for possible cases up to 1994. Patients were included if there was either surgical or radiological evidence of sclerosing encapsulating peritonitis or SBO with tanned or thickened peritoneum in the absence of other causes of SBO. RESULTS: Fifty-four patients were analysed. The duration of continuous PD was mean 52 +/- 30 months, median 48 months and range 8-127 months. Nineteen cases were diagnosed between 1980 and 1989 and 35 between 1990 and 1994, giving mean annual incidences 1.9 and 4.2 per 1000 PD periods respectively. The overall prevalence was 0.7%, which increased progressively with the duration of PD being 1.9, 6.4, 10.8, and 19.4% for patients on dialysis for > 2, 5, 6 and 8 years respectively. Sclerosing encapsulating peritonitis was diagnosed in 87% of cases, SBO in 92%, and haemoperitoneum in 8%. Peritoneal calcification was present in seven cases, all of which had been on PD > 7 years. Peritonitis was associated with 38% of cases with fungal infection in 7%. Treatment with immunosuppression in five patients appeared to result in a favourable outcome in three. The mortality rate was 56%. CONCLUSION: Severe sclerosing peritonitis is a serious complication of peritoneal dialysis and there is a time dependent increase on CAPD.     

A 16-Mb Toggle MRAM With Burst Modes

This paper describes a recently developed 16-Mb toggle magnetic random access memory (MRAM). It has 100-MHz burst modes that are compatible with a pseudo-SRAM even though the toggle cell requires reading and comparing sequences in write modes. To accelerate operating clock frequency, we propose a distributed-driver wide-swing current-mirror scheme, an interleaved and pipelined memory-array group activation scheme, and a noise-insulation switch scheme. These circuit schemes compensate the toggle cell timing overhead in write modes and maintain write-current precision that is essential for the wide operational margin of MRAMs. Because toggle cells are very resistant to write disturbance errors, we designed the 16-Mb MRAM to include a toggle MRAM cell. The MRAM was fabricated with 0.13-mum CMOS and 0.24-mum MRAM processes with five metal layers.     

Estimate of physiological variability of peak latency in single sweep P300

Lengthening is generally accepted method of treatment for extremity length discrepancy. This attractive method carries the risk of many complications that may ruin primary treatment plan. The aim of this paper was to analyze complications and their management in own material consisting of 60 extremities in 58 patients aged 8-37 years. Limb length discrepancy was caused by congenital bony hypoplasia in 44 cases, trauma in 8 and infection in 8 cases. Initial shortening ranged from 4 to 15 cm (mean 6.5 cm). Ilizarov technique was used in 20 cases, Wagner method in 6 cases and DeBastiani in 34 cases. Expected elongation has been achieved in 60% cases; in remaining 40% complications occurred. New bone formation disturbances and axial malalignement were among most severe ones. An autogenic marrow injections were used to stimulate callus formation, osteogenon was administered. Axial malalignement was corrected by osteotomy. Percentage of complications decreased as number of elongations performed increased.     

Transparent Hydroxyapatite Prepared by Hot Isostatic Pressing of Filter Cake

Hydroxyapatite powder was synthesized and formed into a compact in an aqueous medium using a filter-cake method. The compact was hot isostatically pressed at 700° to 1000°C and 100 MPa for 2 h. Fully dense, transparent materials were obtained above 800°C. Both forming and densification methods were found to be important in obtaining transparent materials.