Anaerobic digestion of untreated and treated process water from the hydrothermal carbonisation of spent coffee grounds.

This study investigates the long-term performance of the mesophilic (35 °C) anaerobic mono-digestion of process waters (PW) from the hydrothermal carbonisation (HTC) of spent coffee grounds. At an organic loading rate (OLR) of 0.4 gCOD L-1 d-1, initial instability was seen, but after 40 days and supplementary alkalinity, the digestion stabilised with the chemical oxygen demand (COD) in the untreated PW degraded with 37.8-64.6% efficiency and the yield of methane at 0.16 L gCOD-1. An increase in OLR to 0.8 gCOD L-1 d-1 caused a collapse in biogas production, and resulted in severe instability in the reactor, characterised by falling pH and an increasing volatile fatty acid concentration. Comparatively, the digestion of a treated PW (concentrated in nanofiltration and reverse osmosis after removal of the fouling fraction), at OLR between 0.4 and 0.8 gCOD L-1 d-1, was stable over the entire 117 days of treated PW addition, yielded methane at 0.21 L gCOD-1 and the COD was degraded with an average efficiency of 93.5% - the highest efficiency the authors have seen for HTC PW. Further anaerobic digestion of untreated PW at an average OLR of 0.95 gCOD L-1 d-1 was stable for 38 days, with an average COD degradation of 69.6%, and methane production between 0.15 and 0.19 L gCOD-1. The digestion of treated PW produced significantly higher COD degradation and methane yield than untreated PW, which is likely to be related to the removal of refractory and inhibitory organic material in the post-HTC treatment by adsorption of hydrophobic material.

Culture conditions affect the chemical composition of the exopolysaccharide synthesized by the fungus Aureobasidium pullulans.

AIMS: To identify if culture conditions affect the chemical composition of exopolysaccharide (EPS) produced by Aureobasidium pullulans. METHODS AND RESULTS: In batch airlift and continuously stirred tank (CSTR) reactors the EPS produced with low (0.13 g l(-1) N) initial NaNO(3) or (NH(4))(2)SO(4) levels contained pullulan, with maltotriose as its major component, similar to that synthesized in the airlift reactor with high (0.78 g l(-1) N) initial NaNO(3) levels. EPS produced by CSTR grown cultures with high (NH(4))(2)SO(4) levels contained little pullulan, possibly because of a population shift from unicells to mycelium. This chemical difference may explain why total EPS yields did not fall as they did with cultures grown under identical conditions with high NaNO(3) levels, where the pullulan component of the EPS disappeared. EPS synthesized in N-limiting chemostat cultures of A. pullulans changed little with growth rate or N source, being predominantly pullulan consisting of maltotriose units. CONCLUSIONS: While the EPS chemical composition changed little under N-limiting conditions, high initial medium N levels determined maltotriose content and/or pullulan content possibly by dictating culture morphology. SIGNIFICANCE AND IMPACT OF THE STUDY: These results emphasize the requirement of all studies to determine EPS chemical composition when examining the influence of culture conditions on EPS yields.

The topography of colorectal cancer varies by race/ethnicity and affects the utility of flexible sigmoidoscopy.

Colorectal cancer screening beginning at age 50 is recommended for all Americans considered at "average" risk for the development of colorectal cancer either with flexible sigmoidoscopy and fecal occult blood testing (FOBT) or with colonoscopy. Patients who elect flexible sigmoidoscopy and FOBT undergo full colonoscopy only if left-sided neoplasia is detected or if the FOBT is positive. Unfortunately in blacks and whites most right-sided colorectal lesions are unaccompanied by left-sided sentinel lesions, which leads some to prefer colonoscopic screening in these patients. The topography of colorectal cancer in Asians and Latinos is unavailable. We used 1988-1995 California Cancer Registry data to determine the topography of 105,906 consecutive colorectal cancers among Asian, black, Latino, and white patients. We found that the proportion of colorectal cancer distal to the splenic flexure and therefore detectable by flexible sigmoidoscopy varied by ethnicity: Asian (71%) > Latino (63%) > white (57%) > black (55%); P < 0.001. These differences were significant after adjusting for age and sex. The risk of distal disease relative to whites was 1.61 in Asians, 1.15 in Latinos, and 0.82 in blacks (P < 0.001). Flexible sigmoidoscopy detects a higher proportion of colorectal cancers in Asians and Latinos than in whites or blacks. Further study is needed to assess whether the topography of benign colorectal neoplasia parallels that of malignant disease. Colorectal screening recommendations may need to incorporate racial and ethnic differences in colorectal neoplasia topography.

Cases from the aerospace medicine residents' teaching file. Case #55. Symmetrical peripheral edema in a 33-year-old Army aviator.

Initial presentation, evaluation, differential diagnosis, and aeromedical disposition of a 33-year-old aviator with tropical sprue is discussed. This unusual case was unique in that the applicable flight regulations do not address tropical sprue.

Hepatic synthesis of apoproteins of very low density and high density lipoproteins in perfused rat liver: influence of chronic heavy and moderate doses of ethanol.

The effects of 6 weeks of heavy and moderate ethanol feeding to rats upon lipids and lipoprotein metabolism were determined. As compared to the control group, the heavy ethanol feeding resulted in the following changes: liver weight/kilogram body weight increased by 48% (p less than 0.001) with a concomitant 52% increase (p less than 0.001) in liver protein/kilogram body weight and a 2.75-fold (p less than 0.001) increase in liver total lipids/kilogram body weight. In contrast, liver DNA/kilogram body weight or per liver was not affected significantly. Plasma cholesterol and triglycerides were higher by 53% (p less than 0.01) and 77% (p less than 0.01), respectively. Liver cholesterol and triglycerides were 4.4-fold and 3.8-fold higher (p less than 0.001), respectively. Plasma total A1 was 1.72-fold higher (p less than 0.001), whereas there was no significant difference in plasma apo E levels between the two groups. However, plasma high density lipoproteins (HDl) apo E was 48% lower (p less than 0.02) while the very low density lipoproteins (VLDL) E was 2.15-fold higher (p less than 0.02). Hepatic total protein synthetic rate in the ethanol group was not significantly different from the control group. In contrast, labeled leucine incorporation into the total secretory proteins was inhibited by 36% (p less than 0.01) in ethanol-fed group.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on de novo fatty acid and cholesterol synthesis in the rat.

The effects of 1, 5, 10 and 20 micrograms/kg dosages of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) upon de novo fatty acid and cholesterol synthesis in liver and adipose tissue were determined in pair-fed rats. The incorporation of tritium from 3H2O into tissue lipids was measured. Hepatic and adipose fatty acid synthetic rates (mumoles acetyl units g-1 hr-1) in the control groups were 19.6 +/- 4 and 75.7 +/- 18.5, respectively, and the liver cholesterol synthetic rate was 2.9 +/- 0.5. TCDD (1 microgram/kg) inhibited fatty acid synthesis in the liver and adipose tissue, by 44% and 41%, respectively, and the liver cholesterol synthesis was inhibited by 37%. The extent of these inhibitions increased with increasing dosages of TCDD. The effect of TCDD on sterol synthesis in adipose tissue could not be determined, because the tritium incorporation into the sterol fraction in this tissue was not detectable.

Studies on the mechanism of absorption and distribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the rat.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), the toxic contaminant of Agent Orange, is absorbed essentially by the lymphatic route and is transported predominantly by chylomicrons after intestinal absorption. Plasma disappearance of [3H]TCDD-labeled chylomicrons followed first-order decay kinetics, with two exponential components having half-lives of 0.8 and 30 min, respectively. Liver and adipose tissues together accounted for 74 to 81% of the total radioactivity distributed among various tissues. The i.p. route of administration was as effective as the oral route for uptake in 24 h by the adipose and liver tissues, whereas the s.c. route was less efficient. Adipose tissue exhibited a progressive accumulation of labeled TCDD during the first 24 h, whereas the liver showed an exponential disappearance of the newly absorbed TCDD with a half-life of 21.3 h. In contrast, long-term pharmacokinetics of TCDD in the adipose and liver tissues revealed exponential decay patterns with half-lives of 7.6 and 5.3 weeks, respectively. These results show that the adipose tissue and the liver are the major sites of TCDD storage.

Binding, uptake, and metabolism of chylomicron remnants by hepatocytes from control and chronic ethanol-fed rats.

Chylomicron remnants, but not lymph chylomicrons, showed a receptor-dependent high affinity saturable binding to normal rat hepatocytes. The Scatchard analysis of the specific binding data showed a high affinity binding site for the remnants with a dissociation constant of 0.61 nM, assuming a molecular weight of 50 X 10(6) for chylomicron remnants. Based on the heparin-releasable bound radioactivity, approximately 80% of the bound remnants seemed to be internalized. The binding process was markedly inhibited by pronase as well as by protein synthesis inhibitors. Competitive binding studies revealed that the order of competition for the binding of labeled remnants by homologous unlabeled lipoproteins was remnants greater than chylomicrons greater than very low density lipoproteins greater than high density lipoproteins. Human low density lipoproteins showed virtually no competition. Studies on the catabolism of triacylglycerol moiety of the remnants showed that 15.2% of the 14C label in the triacylglycerol moiety of the remnants was catabolized by the hepatocytes to 14CO2 due to specific interaction. This amounted to 93% of the total 14CO2 evolution. This was in sharp contrast to the catabolism of the triacylglycerol moiety of very low density lipoproteins from human and rat, where most of the 14CO2 evolution was due to pathways associated with nonspecific binding. Chronic ethanol feeding caused a 29% (p less than 0.02) decrease in the dissociation constant of the high affinity binding site of the liver cell for the remnants, whereas the extent of internalization was decreased by 19% (p less than 0.01) as compared to the pair-fed control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Rocket Immunoelectrophoresis of the Entomocidal Parasporal Crystal of Bacillus thuringiensis subsp. kurstaki.

Rocket immunoelectrophoresis was used to quantitate the soluble parasporal crystal of Bacillus thuringiensis subsp. kurstaki. The method described is rapid, reliable, specific, and extremely accurate, and it can be used to measure crystal toxin in commercial microbial insecticides that contain a mixture of spores, vegetative cells, and carrier materials.