Evaluating behavior of oxygen,nitrate, and sulfate during recharge and quantifying reduction rates in a contaminated aquifer

This study evaluates the biogeochemical changes that occur when recharge water comes in contact with a reduced aquifer. It specifically addresses (1) which reactions occur in situ, (2) the order in which these reactions will occur if terminal electron acceptors (TEAs) are introduced simultaneously, (3) the rates of these reactions, and (4) the roles of the aqueous and solid-phase portions of the aquifer. Recharge events of waters containing various combinations of O2, NO3, and SO4 were simulated at a shallow sandy aquifer contaminated with waste fuels and chlorinated solvents using modified push-pull tests to quantify rates. In situ rate constants for aerobic respiration (14.4 day(-1)), denitrification (5.04-7.44 day(-1)), and sulfate reduction (4.32-6.48 day(-1)) were estimated. Results show that when introduced together, NO3 and SO4 can be consumed simultaneously at similar rates. To distinguish the role of aqueous phase from that of the solid phase of the aquifer, groundwater was extracted, amended with NO3 and SO4, and monitored overtime. Results indicate that neither NO3 nor SO4 was reduced during the course of the aqueous-phase study, suggesting that NO3 and SO4 can behave conservatively in highly reduced water. It is clear that sediments and their associated microbial communities are important in driving redox reactions.     

Demonstration of a role for insulin in the regulation of leptin in lactating dairy cows

In lactating dairy cows, the onset of negative net energy balance (EB) at parturition causes a reduction in plasma leptin and is also associated with increased concentration of growth hormone (GH) and decreased concentration of insulin. These observations raise the possibility that opposite changes in plasma insulin and GH are partly responsible for reduced plasma leptin. To test this hypothesis, we first examined the effects of undernutrition without the confounding influence of parturition by using late lactating dairy cows fed 120% of their nutrient requirements or restricted to 33% of maintenance requirements. Plasma leptin was reduced within 24 h of feed restriction, and was associated with increased plasma GH and decreased plasma insulin. Complete food deprivation for 48 h caused similar changes in the plasma concentration of leptin. To determine if an elevation in GH is responsible for the fall in plasma leptin, dairy cows were treated with excipient or bovine somatotropin in early lactation or in late lactation. Growth hormone treatment had no significant effect on plasma leptin irrespective of stage of lactation. Finally, the effects of insulin were studied by performing euglycemic hyperinsulinemic clamps in mid-lactating dairy cows. After 96 h of hyperinsulinemia, plasma leptin was increased significantly. These data indicate that insulin regulates plasma leptin in lactating dairy cows. They also suggest that, in undernourished lactating dairy cows, reduced plasma insulin could account for a portion of the decline in plasma leptin but that elevated plasma GH is unlikely to have a major effect.     

Cloud and fog processing enhanced gas-to-particle partitioning of trimethylamine

An aerosol time-of-flight mass spectrometer (ATOFMS) was used to detect trimethylamine (TMA) in 0.52-1.9 μm particles at urban and rural sites in Southern Ontario during the summer and winter of 2007. During the summer, TMA-containing particles were observed exclusively during high relative humidity or fog events at both the urban and rural sites. In the wintertime, greater concentrations of TMA-containing particles were linked to cloud processing of aerosol in air masses originating from over agricultural and livestock areas. A laboratory study revealed that, at high relative humidity (～ 100%), gas phase TMA at concentrations ranging from 2 to 20,000 ppt partitions preferentially to acidic particles present in the ambient air. On the basis of the field and laboratory studies, it appears that gas phase TMA present in ambient air partitions onto pre-existing particles preferentially during periods of acidic cloud/fog processing, leading to the presence of TMA-containing particles in the 0.52-1.9 μm size range.     

Effect of sodium laurate on ruminal fermentation and utilization of ruminal ammonia nitrogen for milk protein synthesis in dairy cows

A crossover design trial with 4 ruminally and duodenally cannulated lactating dairy cows was conducted to study the effect of sodium laurate on ruminal fermentation, nutrient digestibility, and milk yield and composition. The daily dose of sodium laurate (0, control or 240 g/cow, LA) was divided in 2 equal portions and introduced directly into the rumen through the cannula before feedings. Ruminal samples (29 in 114 h) were analyzed for fermentation variables and protozoal counts. Sodium laurate had no effect on ruminal pH and total and individual volatile fatty acids concentrations. Ruminal ammonia concentration, ammonia N pool size, and the irreversible loss of ammonia N were unaffected by treatment. Compared to control, protozoal counts were reduced by 91% by LA. Carboxymethylcellulase and xylanase activities of ruminal fluid were decreased (by 40 and 36%, respectively), and amylase activity was not affected by LA compared with control. Flow of microbial N to the duodenum was reduced by LA. Dry matter intake and apparent total tract digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber were not different between the 2 treatments. Milk yield, fat-corrected milk yield, milk fat and protein concentrations and yields, and milk urea N content were not affected by treatment. Sodium laurate did not affect transfer of ruminal ammonia-15N into bacterial or milk protein. In conclusion, LA at approximately 0.3% of the rumen weight reduced ruminal protozoal population and had a negative effect on fibrolytic activities of ruminal fluid and microbial protein flow to the intestine. Treatment had no other significant effects on ruminal fermentation, total tract digestibility, or transfer of ruminal ammonia-15N into milk protein.     

The case for fire safe cigarettes made through industry documents

OBJECTIVES: To examine the extensive research undertaken by the tobacco industry over the past 25 years toward development of a fire safe cigarette. METHODS: Research was conducted through a web based search of internal tobacco industry documents made publicly available through the 1998 Master Settlement Agreement. RESULTS: The documents reveal that the tobacco industry produced a fire safe cigarette years ago, but failed to put it on the market. These findings contradict public industry claims that denied the technical feasibility and commercial acceptability of fire safe cigarettes. Internal documents also reveal a decades long, coordinated political strategy used to block proposed legislation and obfuscate the fire safe issue. CONCLUSIONS: Federal legislation mandating fire safe cigarettes is needed.     

Reversibility of lumbar epidural lipomatosis in obese patients after weight-reduction diet

We present three obese patients with symptomatic lumbar epidural lipomatosis. All three were treated with a calorie-controlled diet and considerable weight reduction was achieved. MRI demonstrated a reduction in the epidural fat and relief of thecal sac compression in all three; two also improved clinically.     

Women who have sex with other women: HIV seroprevalence in New York State counseling and testing programs

This report provides HIV seroprevalence data for women who are sexually active with women (WSW) choosing to access services in four of New York State's counseling and testing programs from January 1993 to June 1994. During that period, these programs tested 27,370 women. When questioned about sexual activity since 1978, 3.7% of these women reported sexual activity exclusively with women, 5.3% reported sexual activity with both women and men and 90.1% reported sexual activity exclusively with men. HIV seroprevalence in women sexually active exclusively with women in this sample was calculated at 3.0%, at 4.8% in women sexually active with both women and men and at 2.9% in women sexually active exclusively with men. According to the self-reported data in this study, injecting drug use is, by far, the predominant risk factor for seropositive WSW. Significant HIV-related public health/preventative implications for WSW and their service providers are suggested by this data, including the need for prevention education targeted to WSW who are IDUs, the need to provide culturally sensitive education to WSW detailing safer sexual behaviors both with women and with men as well as the need for evaluation of all risk factors when providing risk reduction education to WSW.     

A noninjury, diet-induced swine model of atherosclerosis for cardiovascular-interventional research

To investigate whether atherosclerotic vascular disease in the microswine model can be induced by atherogenic diet alone and does not require balloon injury or endothelial denudation as widely stated in the literature, 28 female Yucatan microswine were fed a high-fat, high-cholesterol diet, including 2% sodium cholate, for an average of 310 +/- 13 days. Four control swine were placed on a regular diet for an average of 287.2 +/- 7.8 days. Selective coronary arteriography and morphologic and histologic studies were performed at the end of this period. Coronary arteries were fixed in vivo by pressure perfusion of formalin. Angiograms and sequential histologic sections were reviewed by a double-blind team. The angiography did not show apparent disease in all vessels but generally revealed mild irregularity. Quantitatively, there was a 30.5 +/- 3.5% stenosis (mean +/- standard error, P < 0.05 vs. control) in left anterior descending (LAD), 40.7 +/- 4.5% of stenosis in right coronary artery (RCA) (P < 0.01 vs. control), and 24.8 +/- 3.7% of stenosis in left circumflex artery (LCX). The lesions were eccentric in 95% of LCA, 95.8% of RCA, and 75% of LCX, and the remainder were concentric lesions. Typical lesions were characterized by significant intimal proliferation, cholesterol clefts, necrotic cores, heavy extracellular fat deposition, and calcification. Control animals had only occasional, minimal intimal lipid deposition in coronary arteries. These findings suggest that the Yucatan microswine is an ideal coronary atherosclerosis animal model for vascular research. Lesions can be induced by atherogenic diet alone. Cholesterol uptake is increased by adding sodium cholate to the feed. Moreover, balloon injury of the intima or media is not required to induce significant atherosclerotic lesions in coronary arteries.