856 research outputs found

    Intermittent Sand Filtration to Upgrade Existing Wastewater Treatment Facilities

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    Tricarboxylic acid cycle enzyme activities in a mouse model of methylmalonic aciduria

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    Methylmalonic acidemia (MMA) is a propionate pathway disorder caused by dysfunction of the mitochondrial enzyme methylmalonyl-CoA mutase (MMUT). MMUT catalyzes the conversion of methylmalonyl-CoA to succinyl-CoA, an anaplerotic reaction which feeds into the tricarboxylic acid (TCA) cycle. As part of the pathological mechanisms of MMA, previous studies have suggested there is decreased TCA activity due to a toxic inhibition of TCA cycle enzymes by MMA related metabolites, in addition to reduced anaplerosis. Here, we have utilized mitochondria isolated from livers of a mouse model of MMA (Mut-ko/ki) and their littermate controls (Ki/wt) to examine the amounts and enzyme functions of most of the TCA cycle enzymes. We have performed mRNA quantification, protein semi-quantitation, and enzyme activity quantification for TCA cycle enzymes in these samples. Expression profiling showed increased mRNA levels of fumarate hydratase in the Mut-ko/ki samples, which by contrast had reduced protein levels as detected by immunoblot, while all other mRNA levels were unaltered. Immunoblotting also revealed decreased protein levels of 2-oxoglutarate dehydrogenase and malate dehydrogenase 2. Interesting, the decreased protein amount of 2-oxoglutarate dehydrogenase was reflected in decreased activity for this enzyme while there is a trend towards decreased activity of fumarate hydratase and malate dehydrogenase 2. Citrate synthase, isocitrate dehydrogenase 2/3, succinyl-CoA synthase, and succinate dehydrogenase are not statistically different in terms of quantity of enzyme or activity. Finally, we found decreased activity when examining the function of methylmalonyl-CoA mutase in series with succinate synthase and succinate dehydrogenase in the Mut-ko/ki mice compared to their littermate controls, as expected. This study demonstrates decreased activity of certain TCA cycle enzymes and by corollary decreased TCA cycle function, but it supports decreased protein quantity rather than toxic inhibition as the underlying mechanism of action. SUMMARY: Methylmalonic acidemia (MMA) is an inborn metabolic disorder of propionate catabolism. In this disorder, toxic metabolites are considered to be the major pathogenic mechanism for acute and long-term complications. However, despite optimized therapies aimed at reducing metabolite levels, patients continue to suffer from late complications, including metabolic stroke and renal insufficiency. Since the propionate pathway feeds into the tricarboxylic acid (TCA) cycle, we investigated TCA cycle function in a constitutive MMA mouse model. We demonstrated decreased amounts of the TCA enzymes, Mdh2 and Ogdh as semi-quantified by immunoblot. Enzymatic activity of Ogdh is also decreased in the MMA mouse model compared to controls. Thus, when the enzyme amounts are decreased, we see the enzymatic activity also decreased to a similar extent for Ogdh. Further studies to elucidate the structural and/or functional links between the TCA cycle and propionate pathways might lead to new treatment approaches for MMA patients

    Review paper: Evaluation of Techniques for Algae Removal from Wastewater Stabilization Ponds

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    Introduction: Approximately 90 percent of the wastewater lagoons in the United States are located in small communities of 5,000 people or less. These communities, many with an average daily wastewater flow of only 175,000 - 200,000 gallons, do not have the resources to keep man at the lagoon sites throughout the day (38). A high degree of technical knowhow is usually lacking in these communities. Often only periodic inspection or maintenance is carried out by the general municipal work force. Therefore, the development of a relatively inexpensive method that does not require sophisticated and constant operation or extensive maintenance is needed to polish these effluents. Most regulatory agencies are adopting more stringent water quality standards, enforcement of which will necessitate changes in present treatment methods and the philosophy of wastewater treatment. Small communities utilizing stabilization ponds will be affected most drastically by new standards. Because most communities utilizing ponds are relatively small and installed ponds primariliy to avoid operating costs, it is unlikely that modifications requiring significant increases in operation will be acceptable. Therefore, the most sophisticated alternatives for upgrading treatment must be excluded from a practicable solution to solids removal from stabilization pond effluent

    Cultural and economic complementarities of spatial agglomeration in the British television broadcasting industry: Some explorations.

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    This paper considers the processes supporting agglomeration in the British television broadcasting industry. It compares and contrasts the insights offered by the cultural turn in geography and more conventionally economic approaches. It finds that culture and institutions are fundamental to the constitution of production and exchange relationships and also that they solve fundamental economic problems of coordinating resources under conditions of uncertainty and limited information. Processes at a range of spatial scales are important, from highly local to global, and conventional economics casts some light on which firms are most active and successful

    Care coordination among pediatricians and dentists: a cross-sectional study of opinions of North Carolina dentists

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    Abstract: Background: Care coordination between physicians and dentists remains a challenge. This study of dentists providing pediatric dental care examined their opinions about physicians’ role in oral health and identified factors associated with these opinions. Methods: North Carolina general and pediatric dentists were surveyed on their opinions of how physicians should proceed after caries risk assessment and evaluation of an 18-month-old, low risk child. We estimated two multinomial logistic regression models to examine dentists’ responses to the scenario under the circumstances of an adequate and a limited dental workforce. Results: Among 376 dentists, 52% of dentists indicated physicians should immediately refer this child to a dental home with an adequate dental workforce. With a limited workforce, 34% recommended immediate referral. Regression analysis indicated that with an adequate workforce guideline awareness was associated with a significantly lower relative risk of dentists’ recommending the child remain in the medical home than immediate referral. Conclusions: Dentists’ opinions and professional guidelines on how physicians should promote early childhood oral health differ and warrant strategies to address such inconsistencies. Without consistent guidelines and their application, there is a missed opportunity to influence provider opinions to improve access to dental care

    The acquisition of Sign Language: The impact of phonetic complexity on phonology

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    Research into the effect of phonetic complexity on phonological acquisition has a long history in spoken languages. This paper considers the effect of phonetics on phonological development in a signed language. We report on an experiment in which nonword-repetition methodology was adapted so as to examine in a systematic way how phonetic complexity in two phonological parameters of signed languages — handshape and movement — affects the perception and articulation of signs. Ninety-one Deaf children aged 3–11 acquiring British Sign Language (BSL) and 46 hearing nonsigners aged 6–11 repeated a set of 40 nonsense signs. For Deaf children, repetition accuracy improved with age, correlated with wider BSL abilities, and was lowest for signs that were phonetically complex. Repetition accuracy was correlated with fine motor skills for the youngest children. Despite their lower repetition accuracy, the hearing group were similarly affected by phonetic complexity, suggesting that common visual and motoric factors are at play when processing linguistic information in the visuo-gestural modality

    Does Nonrandom Nest Placement Imply Nonrandom Nest Predation?: a Reply

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    In response to the critique by Schmidt and Whelan (Condor 101 (4): 916-920, 1999), we find that the relationship between nest success and tree selectivity is dependent upon inclusion or exclusion of particular tree species, whether or not years are pooled, and the selectivity index used. We question their use of point estimates of nest success with extremely high variances, defend our index, question the application of the Chesson (1983) index to our data, and explain the need to analyze years separately. Bottomland hardwood forest systems are extremely variable; hydroperiods alter the suitability of nesting substrates, availability of alternative food, and behavior of predators and their prey. Given these features, actively searching for Acadian Flycatcher (Empidonax virescens) nests is seldom an efficient predator foraging strategy. Therefore, these predation events are best described as random; nests are principally encountered opportunistically by generalist predators while searching for other prey
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