Factors affecting alkalinity generation by successive alkalinity-producing systems: regression analysis

Use of successive alkalinity-producing systems (SAPS) for treatment of acidic mine drainage (AMD) has grown in recent years. However, inconsistent performance has hampered widespread acceptance of this technology. This research was conducted to determine the influence of system design and influent AMD chemistry on net alkalinity generation by SAPS. Monthly observations were obtained from eight SAPS cells in southern West Virginia and southwestern Virginia. Analysis of these data revealed strong, positive correlations between net alkalinity generation and three variables: the natural log of limestone residence time, influent dissolved Fe concentration, and influent non-Mn acidity. A statistical model was constructed to describe SAPS performance. Subsequent analysis of data obtained from five systems in western Pennsylvania (calibration data set) was used to reevaluate the model form, and the statistical model was adjusted using the combined data sets. Limestone residence time exhibited a strong, positive logarithmic correlation with net alkalinity generation, indicating net alkalinity generation occurs most rapidly within the first few hours of AMD-limestone contact and additional residence time yields diminishing gains in treatment. Influent Fe and non-Mn acidity concentrations both show strong positive linear relationships with net alkalinity generation, reflecting the increased solubility of limestone under acidic conditions. These relationships were present in the original and the calibration data sets, separately, and in the statistical model derived from the combined data set. In the combined data set, these three factors accounted for 68% of the variability in SAPS systems performance.

Olfactory response to mushroom composting emissions as a function of chemical concentration

Odor pollution is a major problem facing mushroom [Agaricus bisporus (Lange) Imbach] compost production. Techniques for quantifying mushroom composting odors are needed to assess the effectiveness of odor control measures. Odor samples were obtained in nalophane bags from 11 mushroom composting sites. Samples were collected 0.2 m downwind from the pre-wetting heaps (aerated or unaerated) of raw composting ingredients (wheat straw, poultry and horse manures, and gypsum) and subsequent Phase I composting windrows or aerated tunnels. The odor concentrations (OCs) of the samples were assessed using serial dilution olfactometry and the chemical composition of the samples was determined using gas chromatography-mass spectrometry (GC-MS), both 24 h after sampling. Gas detector tubes were used for on-site measurement of gaseous compounds. Odorants that exceeded their published olfactory detection thresholds by the greatest order of magnitude, in decreasing order, were: H2S, dimethyl sulfide (DMS), butanoic acid, methanethiol, and trimethylamine. Concentrations of NH3 were not significantly correlated with OC, and they were not significantly affected by the use of aeration. Aeration reduced the OC and the combined H2S + DMS concentrations by 87 and 92%, respectively. There was a very close correlation (r = 0.948, P < 0.001) between the OC of bag samples and the combined H2S + DMS concentrations, measured on-site with detector tubes. This relationship was unaffected by the NH3 concentration or the type of compost: aerated or unaerated, pre-wet or Phase I, poultry manure-based or horse and poultry manure-based compost. Prediction of the OC will enable rapid and low-cost identification of odor sources on mushroom composting sites.

Human adenoviruses and coliphages in urban runoff-impacted coastal waters of Southern California

A nested-PCR method was used to detect the occurrence of human adenovirus in coastal waters of Southern California. Twenty- to forty-liter water samples were collected from 12 beach locations from Malibu to the border of Mexico between February and March 1999. All sampling sites were located at mouths of major rivers and creeks. Two ultrafiltration concentration methods, tangential flow filtration (TFF) and vortex flow filtration (VFF), were compared using six environmental samples. Human adenoviruses were detected in 4 of the 12 samples tested after nucleic acid extraction of VFF concentrates. The most probable number of adenoviral genomes ranged from 880 to 7,500 per liter of water. Coliphages were detected at all sites, with the concentration varying from 5.3 to 3332 PFU/liter of water. F-specific coliphages were found at 5 of the 12 sites, with the concentration ranging from 5.5 to 300 PFU/liter. The presence of human adenovirus was not significantly correlated with the concentration of coliphage (r = 0.32) but was significantly correlated (r = 0.99) with F-specific coliphage. The bacterial indicators (total coliforms, fecal coliforms, and enterococci) were found to exceed California recreational water quality daily limits at 5 of the 12 sites. However, this excess of bacterial indicators did not correlate with the presence of human adenoviruses in coastal waters. The results of this study call for both a reevaluation of our current recreational water quality standards to reflect the viral quality of recreational waters and monitoring of recreational waters for human viruses on a regular basis.

Viability, susceptibility to peroxidation and fatty acid composition of boar semen during liquid storage

The changes in viability, susceptibility to peroxidation and fatty acid composition of total phospholipid were studied in boar spermatozoa during 5 day liquid storage in a standard or alpha-tocopherol (alphaT) enriched diluent. The sperm rich fraction of the ejaculates was collected from 6-month old boars. Sperm viability progressively decreased during storage and alphaT inclusion into the diluent significantly inhibited this trend. alphaT inclusion also decreased significantly peroxidation (TBARS production of spermatozoa). Spermatozoa stored in the treatment diluent became rapidly enriched in alphaT with a concomitant decrease of alphaT content in the medium. The proportion of polyunsaturates, mainly 22:6n-3, decreased with a complementary increase in the content of the saturates, mainly 18:0. The inclusion of alphaT into the diluent was effective in totally preventing the significant decrease of 22:6n-3 observed in sperm phospholipid in the control samples during the storage period. It is concluded that the alphaT inclusion in the boar semen diluent increased cell viability through its prevention of an oxidative reduction in the levels of the major polyunsaturated fatty acids, namely 22:6n-3.

Sexuality and genetic identity in the Agaricus section Arvenses

Twelve wild collections and one commercial strain were used to characterize breeding systems and to develop molecular identities in the Arvenses section of the genus Agaricus, which includes the "horse mushroom" A. arvensis. Two morphotypes were identified based on macro- and micromorphological features. However, not all collections could be delimited by conventional taxonomic characters. Sequencing of the small subunit intergenic spacer (ITS) region (368 to 370 bp) of the rRNA genes clearly resolved the 13 collections into two clusters consistent with the identified morphotypes. Single-spore progenies and mating type testers were established and used to test intra- and interstock compatibility. The two compatibility groups identified were consistent with ITS clusters. Compatibility group I stocks readily interbred within the constraints of a unifactorial heterothallic system with a multiallelic mating type factor. Compatibility group II had a more restricted breeding pattern, and interactions were difficult to predict on the basis of mating type. Morphological data, ITS sequences, and the ability to interbreed suggest that these collections are part of a complex of interrelated species. Single-spore, homokaryotic isolates from both compatibility groups were able to fruit in compost culture, and two of the collections may represent natural homokaryotic fruiting. We conclude that species from the section Arvenses have versatile unifactorial heterothallic life cycles that permit both interbreeding and homokaryotic fruiting.

Orofacial exercises for babies with breastfeeding problems?

Young babies occasionally have aberrant orofacial movements that may appear to be the cause of their breastfeeding difficulties. There has been a trend to treat this by introducing corrective exercises for the affected muscle(s). Such treatments have had their bases in therapeutic measures that were originally designed for severely neurologically impaired babies. In fact, most babies with breastfeeding problems are neurologically intact, with many needing only minimal but specific interventions predominantly involving the gape response, attachment and positioning. If the baby's gape response is poor, a minimal amount of breast tissue is taken into the baby's mouth, and abnormal orofacial movements during breastfeeds are the automatic result. This paper re-examines the use of orofacial exercises--often called "suck training"--for babies with breastfeeding problems. There can be negative results from using specific orofacial exercises in an arbitrary or generalised manner. Precautions and guidelines for appropriate corrective measures are discussed.

Therapeutic teat use for babies who breastfeed poorly

Much has been written about suck confusion due to a baby's oral experience with objects other than the breast--but how much difference is there in the relative impacts on a baby's ineffective suck if a teat is used instead of other currently accepted techniques such as cup and finger feeding? Mothers who seek the help of a lactation consultant will commonly already be using bottles and teats as part of their management regime for a difficult situation. Especially if the problems are well developed and complex, many mothers will not be able to accept unfamiliar alternatives such as cup and finger feeding and prefer to wean rather than do so. Current teat designs have evolved with no reference to Woolridge's landmark research published over ten years ago which clearly demonstrated how normal breastfeeding works. Rather, manufacturers offer consumers an array of teats which have been shortened in length and distorted in conformation when compared with teats available thirty years ago which coincidentally were a closer physiological match with the positioning of the nipple and breast tissues in the mouth of a breastfeeding baby than teats designed and produced since then. Fortunately one UK manufacturer still markets this thirty year old style of teat in a flow rate suitable for very young babies. Over a three year period, we at first hesitantly, but with increasing confidence asked mothers to use this teat when suck retraining and supplementation were indicated. We are able to report that use of these teats has resulted in a success rate in excess of 90% converting babies with significant sucking problems into fully effective breastfeeders.

A comparison of intubation success for paediatric transport team paramedics using lighted vs regular tracheal tube stylets

We conducted a prospective randomized study of success rate and time to intubation using Trachlight and Surch-Lite lighted stylets versus a regular tracheal tube stylet, in a training setting. Participants, 18 paediatric transport paramedics, performed two intubations with each of the three devices, using an airway management trainer. There was no significant difference in mean time for intubation between the three devices. The times for external confirmation of correct tube placement were comparable using the two lighted stylets. External confirmation of the tube placement using the lighted stylets was quicker than laryngoscopic visualization. In darkness, with a nonfunctioning laryngoscope, intubations were successfully performed 100% of the time with the lighted stylet, but only 11% of the time with the regular stylet. All paramedics felt that a lighted stylet would be a useful airway management adjunct for the transport environment for complicated intubations or for use in very high or low levels of ambient light.

Effect of vitamin E and selenium supplementation of cockerel diets on glutathione peroxidase activity and lipid peroxidation susceptibility in sperm, testes, and liver

The phospholipids of avian spermatozoa are characterized by high proportions of arachidonic (20:4n-6) and docosatetraenoic (22:4n-6) fatty acids and are therefore sensitive to lipid peroxidation. Alpha-tocopherol and glutathione peroxidase [GSH-Px] are believed to be the primary components of the antioxidant system of the spermatozoa. The present study evaluates the effect of vitamin E and vitamin E plus Se supplementation of the cockerel diet on GSH-Px activity, vitamin E accumulation, and lipid peroxidation in the spermatozoa, testes, and liver. At the beginning of the experiment 75 Rhode Island Red cockerels were divided into five groups, kept in individual cages, and fed a wheat-barley-based ration balanced in all nutrients. Supplements fed to the different groups were as follows: vitamin E, 0, 20, 200, 20, and 200 mg/kg to groups 1-5, respectively, with groups 4 and 5 also receiving 0. 3 mg Se/kg. The vitamin E supplementation produced increased levels of alpha-tocopherol in semen, testes, and liver. The inclusion of the Se into the cock diet had a significant (P < 0.01) stimulating effect on GSH-Px activity in seminal plasma, spermatozoa, testes, and liver. The increased vitamin E concentration in the spermatozoa was associated with a reduction in their susceptibility to lipid peroxidation. Similarly, the increased GSH-Px activity provided enhanced protection against lipid peroxidation.

Red nucleus inhibits breathing during hypoxia in neonates

Conscious, anaesthetized and decerebrate young mammals respond to acute hypoxia with an initial increase in breathing followed by a fall to, or to below, pre-hypoxic levels--the biphasic ventilatory response. The ventilatory rise is due to sustained hypoxic stimulation of the peripheral chemoreceptors. We present evidence from brain stem and peripheral chemoreflex studies supporting the concept that, in addition to the peripheral chemoreceptors, hypoxia also activates brain stem pathways that inhibit ventilation. A key part of the inhibitory pathway is an area within the red nucleus. Destruction of this area in young decerebrate rabbits abolishes the ventilatory fall during hypoxia, yet has no effect on respiratory control during normoxia and does not affect arterial blood pressure changes in hypoxia. In support of this hypothesis, we report that there are neurones within the red nucleus that increase their discharge in hypoxia. The role of higher brain stem/hypothalamic function in central respiratory control during hypoxia in the fetus and neonate are considered.

Red nucleus lesions abolish the biphasic respiratory response to isocapnic hypoxia in decerebrate young rabbits

1. The respiratory response to isocapnic hypoxia (inspired O2 fraction (FI,O1), 0.1-0.12) was measured in twelve vagotomized, paralysed, artificially ventilated young rabbits (aged 26.6 +/- 0.4 days), following pre-collicular decerebration. Phrenic nerve efferent activity was used as an index of central respiratory output (RO). In hypoxia RO increased after 1-2 min (phase 1) but decreased over the subsequent 3-4 min to, or below, the pre-hypoxic control level (phase 2). 2. We used electrical stimulation to target areas in the mesencephalon which inhibit RO. Profiles of the response to stimulation were determined in a grid of electrode penetrations made mediolaterally and rostrocaudally at the level of the superior colliculi, in normoxia. Histology confirmed that stimulation in the red nucleus (RN) inhibited RO profoundly. 3. Electrolytic lesions were made bilaterally in RN inhibitory sites or in adjacent areas. The respiratory response to isocapnic hypoxia was measured again post-lesioning. 4. In six rabbits with bilateral lesions in the RN, phase 2 of the respiratory response was abolished and RO remained elevated throughout the hypoxic exposure. However, in six rabbits with unilateral lesions in the RN, or with bilateral lesions placed in areas outside the RN that did not inhibit RO on electrical stimulation, the respiratory response remained biphasic. 5. In both groups of animals, blood pressure increased during 1-3 min of hypoxia before decreasing to pre-hypoxic levels. This cardiovascular response remained biphasic irrespective of whether animals showed a biphasic respiratory response or a sustained increase in RO after lesioning. 6. We conclude that structures within the RN are crucial to the mechanism producing a fall in RO during isocapnic hypoxaemia in the neonate.

The effect of dietary lipid changes on the fatty acid composition and function of liver, heart and brain mitochondria in the rat at different ages

A correlation between dietary lipids and cellular enzyme activities is a problem that has only been partially addressed by nutritionists. Therefore, changes in the fatty acid composition and the activities of some key metabolic enzymes (ubiquinol-2-cytochrome c reductase (EC 1.10.2.2), cytochrome oxidase (EC 1.9.3.1) and ATPase (EC 3.6.1.3)) in the mitochondria of liver, heart and brain of rats fed on diets differing extensively in their polyunsaturated fatty acid compositions have been investigated. The results showed that fatty acid compositional changes brought about by the dietary differences were associated with extensive changes in the activities of these key enzymes in the mitochondria. The extent of the influence differed considerably with the period over which the diets were fed. The role of dietary lipids to effect changes through the preservation of membrane structural integrity is discussed.

Hospital rightsizing: in line with long-term strategies and economic realities

After two years of difficult financial times, the Kitchener-Waterloo Hospital was faced with another upcoming year of tight fiscal constraint. In February 1991, the hospital implemented a program review process to align its services with the hospital's long-term strategy and economic realities. The authors present a thorough review of the literature pertaining to downsizing decisions. From a practical perspective they demonstrate a downsizing process, its implications and lessons to be learned so that a "rightsizing" exercise can be implemented to minimize the effects of the program and staff reductions while focusing on the positive long-term benefits of strategic planning. Although downsizing is a difficult process, the Kitchener-Waterloo Hospital was able to develop and implement a plan that minimized the impact on the hospital services and its staff. A reduction in expenses of over $2 million was achieved without having to lay off any permanent hospital staff. This was achieved by streamlining programs, reducing management supervisory positions and eliminating 50 full-time equivalent positions through attrition. Ultimately, the hospital's board, senior management, medical staff and employees felt that a rightsizing decision had been made, one which minimized the negative impact of restructuring on service delivery, hospital employees and the community served.

Executive performance: the demands of the 1990s

Top executives will be required to have strong leadership skills, combined with solid communication and team-building skills, to move their organizations through a decade that will promise tight fiscal constraint, increasing involvement in the decision-making process from medical staff, trustees, government officials and facility personnel. The evaluation of the chief executive officer (CEO) will continue along traditional lines with the development of goals and objectives in defined areas of accountability. There will, however, be increased emphasis on the development of measurable standards, and the CEO's ability to lead the organization, motivate the organization's people resources and reallocate resources to meet the organization's mission and the health care needs of the community.

The effects of ingestion time of gliclazide in relationship to meals on plasma glucose, insulin and C-peptide levels

The effect of altering the timing of gliclazide administration in relation to a meal was studied in ten type 2 (non-insulin dependent) chronically treated diabetics. Gliclazide was given 30 min before, at the start of and 30 min after breakfast or omitted altogether. Plasma gliclazide was present at greater than 2 mg/l throughout the study periods. Administration at 30 min after the meal significantly delayed the time to peak for plasma gliclazide. No significant difference was noted in plasma glucose, insulin or c-peptide patterns with any protocol. It is concluded that, in clinical practice, with chronically treated diabetics the timing of gliclazide ingestion in relation to meals is not critical.

Determinants of the pressor effect of phenylpropanolamine in healthy subjects

Phenylpropanolamine (PPA) is frequently used in over-the-counter diet aids and cold medicines, In view of concern about the safety of this sympathomimetic agent, we undertook a double-blind, multicenter clinical trial to determine the factors that influence the pressor effect of short-term oral administration of PPA in healthy individuals. Eight hundred eighty-one healthy individuals in four categories of body weight were randomized to receive placebo capsules three times per day (n = 286), a 75-mg sustained-release PPA hydrochloride preparation once per day (n = 296) followed by two doses of placebo capsules, or a 25-mg immediate-release PPA hydrochloride preparation three times per day (n = 299). The median age of the study population was 28 years, 56% were men, 73% were white, and 47% were in excess of 30% above their ideal body weight. Measurements of pulse rate and supine and standing blood pressure were made 11 times during the day of PPA administration. A statistically significant but clinically unimportant pressor effect for the short-term administration of PPA was observed. The effect occurred in the first 6 hours after administration and was greater in the sustained-release group. Significant independent determinants of the pressor effect of PPA were baseline diastolic blood pressure, baseline body weight, and treatment.

Spatial spread of in-field afferent inhibition in the cat's spinocervical tract

1. Extracellular microelectrode recordings were made from twenty-three spinocervical tract (SCT) cells in the lumbar spinal cord of cats anaesthetized with chloralose and paralysed with gallamine triethiodide. Excitation and inhibition of the cells were elicited by applying small brief (4 mN, 60 ms) localized jets of air to the clipped hair in and around the receptive fields. 2. Receptive field extents ranged from 40 to 180 mm. Excitation occurred in the period 30-130 ms after the start of the stimulus, and in-field afferent inhibition from 130 ms up to 700 ms or more. The inhibition was manifest as a reduction in background discharge and as a reduction in responsiveness to a test stimulus which followed a conditioning stimulus. 3. When the conditioning stimulus was spatially separated from the test stimulus, the degrees of in-field afferent inhibition depended on the spatial separation, even when both were within the excitatory receptive field. The spatial spread of in-field afferent inhibition was limited to 100 mm or less. 4. In two units only, afferent inhibition was produced from a narrow strip just outside the excitatory receptive field. In the other units, it could only be produced from within the excitatory receptive field. 5. The results suggest that the inhibitory input to SCT cells is organized in subdomains no more than 100 mm across, which may correspond to the receptive fields of interneurones between the primary afferent fibres and the SCT cells.

Subjective profile of phenylpropanolamine: absence of stimulant or euphorigenic effects at recommended dose levels

A total of 837 healthy volunteers presenting with various degrees of obesity participated in a large-scale, double-blind, placebo-controlled evaluation of the subjective effects of phenylpropanolamine (PPA), with particular attention to measurement of the euphoriant or stimulant potential of therapeutic doses of the compound. Dosage forms studied were PPA 75 mg sustained release, PPA 25 mg, and placebo. Subjects were recruited from four independent clinical sites. At each site, subjects were stratified according to degree of overweight (normal, mildly overweight, moderately overweight, or severely overweight) and randomly assigned to one of the three drug treatment regimens. Subjective effects were measured 11 times during the 12-hour experimental session using a short-form version of the Addiction Research Center Inventory. Data analysis did not indicate discernible subjective effects that would differentiate PPA from placebo, but did show typical circadian fluctuations. These results provided evidence that therapeutic doses of PPA do not produce the euphoriant or "stimulant" subjective effects that characterize drugs of abuse.

Descending influences on the cutaneous receptive fields of postsynaptic dorsal column neurones in the cat

1. The influence of activity in descending systems on the cutaneous receptive field properties of postsynaptic dorsal column (PSDC) neurones has been investigated in chloralose-anaesthetized cats. The main aim of the study was to determine whether the receptive field boundaries of PSDC neurones are under the control of systems descending from the brain. 2. Single-unit recordings were made from the ascending axons of PSDC units in the dorsal columns. Receptive fields were analysed using light tactile and noxious mechanical and thermal stimuli, both before and during a reversible block of spinal conduction produced by cooling the cord rostral of the recording site. 3. The light tactile excitatory fields of PSDC neurones were largely unaffected by the cold-block procedure. 4. In contrast, both the sensitivity of PSDC neurones to noxious stimuli and the area of skin from which they could be effectively excited by such stimuli were found to be profoundly modified by interruption of descending activity. Two-thirds of the units excited by noxious pinch responded more vigorously in the cold-blocked state and one-half from an expanded area of skin. Responses to noxious radiant heat were similarly modified. 5. Inhibition evoked in PSDC neurones, whether by light tactile or noxious stimuli, involved predominantly segmental mechanisms since it remained effective in the cold-blocked state. 6. It is concluded that neurones of the PSDC system are amongst those dorsal horn neurones with receptive field geometries which may be modified by activity in descending systems.