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Selected AbstractsUltrasonic treatment of waste activated sludgeENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2006Raf Dewil Abstract Activated sludge processes are key technologies to treat wastewater. These biological processes produce huge amounts of waste activated sludge (WAS), now commonly called biosolids. Mechanical, thermal, and/or chemical WAS conditioning techniques have been proposed to reduce the sludge burden. The ultrasonic treatment of WAS is quite novel. The present paper reports on extensive investigations using an ultrasonic treatment of WAS, to study its potential to meet one or all of four objectives: (1) reduce WAS quantities; (2) achieve a better dewaterability; (3) provoke a release of soluble chemical oxygen demand (COD) from the biosolids, preferably transformed into biodegradable organics; and (4) possibly destroy the filamentous microorganisms responsible for sludge bulking. Although meeting these objectives would help to solve the problems cited, the energy consumption could be a considerable drawback: the paper will thus assess whether all or some objectives are met, and at what operational cost. A literature survey defines the occurring phenomena (cavitation) and the important operation parameters [such as frequency, duration, specific energy input (SE)]. The experiments are carried out in a batch reactor of volume up to 2.3 L. The ultrasonic equipment consisted of a generator, a converter, and a sonotrode, supplied by Alpha Ultrasonics under the brand name of Telsonic. Three different kinds of sludge were tested, with different concentrations of dry solids (DS) between approximately 3.5 and 14 g DS/L WAS. Ultrasonic energy was introduced in a continuous manner (against possible pulsed operation). The major operational parameters studied include duration of the ultrasonic treatment and specific energy input. The applied frequency was set at 20 kHz. The release of COD from the WAS phase into the filtrate phase is a function of the specific energy input with yields of nearly 30% achievable at SE values of 30,000 kJ/kg DS. A major fraction of the COD is transformed into biodegradable organics (BOD). The reduction in DS fraction of the sludge is proportional to the COD release rates. Although the DS content is reduced, the dewaterability of the sludge is not improved. This reflects itself in increased filtration times during vacuum filtration and in increased values of the capillary suction time (CST). This more difficult dewaterability is the result of considerably reduced floc sizes, offering an extended surface area: more surface water is bound (CST increases) and the filterability decreases as a result of clogging of the cake. To reach the same dryness as for the untreated cake, the required dosage of polyelectrolyte is nearly doubled when the SE of the ultrasound treatment is increased from 7500 to 20,000 kJ/kg DS. The ultrasonic reduction of filamentous WAS organisms is not conclusive and very little effect is seen at low intensities and short treatment durations. Microscopic analysis of the WAS identified the dominant presence of Actynomyces. The release of soluble COD and BOD certainly merit further research. © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source] Using GIS to relate small mammal abundance and landscape structure at multiple spatial extents: the northern flying squirrel in Alberta, CanadaJOURNAL OF APPLIED ECOLOGY, Issue 3 2005MATTHEW WHEATLEY Summary 1It is common practice to evaluate the potential effects of management scenarios on animal populations using geographical information systems (GIS) that relate proximate landscape structure or general habitat types to indices of animal abundance. Implicit in this approach is that the animal population responds to landscape features at the spatial grain and extent represented in available digital map inventories. 2The northern flying squirrel Glaucomys sabrinus is of particular interest in North American forest management because it is known from the Pacific North-West as a habitat specialist, a keystone species of old-growth coniferous forest and an important disperser of hypogeous, mycorrhizal fungal spores. Using a GIS approach we tested whether the relative abundance of flying squirrel in northern Alberta, Canada, is related to old forest, conifer forest and relevant landscape features as quantified from management-based digital forest inventories. 3We related squirrel abundance, estimated through live trapping, to habitat type (forest composition: conifer, mixed-wood and deciduous) and landscape structure (stand height, stand age, stand heterogeneity and anthropogenic disturbance) at three spatial extents (50 m, 150 m and 300 m) around each site. 4Relative abundances of northern flying squirrel populations in northern and western Alberta were similar to those previously reported from other regions of North America. Capture rates were variable among sites, but showed no trends with respect to year or provincial natural region (foothills vs. boreal). 5Average flying squirrel abundance was similar in all habitats, with increased values within mixed-wood stands at large spatial extents (300 m) and within deciduous-dominated stands at smaller spatial extents (50 m). No relationship was found between squirrel abundance and conifer composition or stand age at any spatial extent. 6None of the landscape variables calculated from GIS forest inventories predicted squirrel abundance at the 50-m or 150-m spatial extents. However, at the 300-m spatial extent we found a negative, significant relationship between average stand height and squirrel abundance. 7Synthesis and applications. Boreal and foothill populations of northern flying squirrel in Canada appear unrelated to landscape composition at the relatively large spatial resolutions characteristic of resource inventory data commonly used for management and planning in these regions. Flying squirrel populations do not appear clearly associated with old-aged or conifer forests; rather, they appear as habitat generalists. This study suggests that northern, interior populations of northern flying squirrel are probably more related to stand-level components of forest structure, such as food, microclimate (e.g. moisture) and understorey complexity, variables not commonly available in large-scale digital map inventories. We conclude that the available digital habitat data potentially exclude relevant, spatially dependent information and could be used inappropriately for predicting the abundance of some species in management decision making. [source] Effects of a Brazilian herbal compound as a cosmetic eyecare for periorbital hyperchromia ("dark circles")JOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2009Samara Eberlin PhD Summary Background, Evidence suggests that periorbital hyperchromia (dark circles) occurs mainly as a consequence of postinflammatory hemodynamic congestion producing a typical bruising aspect on the lower eyelids. Aims, To evaluate the clinical effects of Pfaffia paniculata/Ptychopetalum olacoides B./Lilium candidum L.-associated compound (PPLAC) on periorbital hyperchromia and to study in vitro its underlying anti-inflammatory and antioxidant mechanisms. Methods, Twenty-one volunteers presenting with periorbital hyperchromia received a serum sample containing 5.0% PPLAC, which was applied topically in the periorbital area twice a day for 28 days. Skin color was measured using variations in the individual typological angle (,ITA0) and skin luminance (,L*) calculated in the area around the eyes and in the adjacent area. Colorimetric readings were taken at the onset and end of the 28-day treatment. Volunteers were also asked to fill out a questionnaire concerning the improvement in "dark circles." The anti-inflammatory and antioxidant effects of PPLAC were measured by quantification of prostaglandin E2, leukotriene B4, histamine, and superoxide dismutase levels using an in vitro model of human skin culture. Results, Topical application of PPLAC led to a significant improvement in skin luminance and tone in the periorbital area, which was demonstrated by increased values of ITA0 and L* in about 90% of volunteers. In addition, subjects reported reduced intensity and improved appearance of "dark circles." A dose-dependent decreased production of inflammatory mediators, concomitant to increased antioxidant enzyme levels, was observed in our in vitro studies, under basal and lipopolysaccharide-stimulated conditions. Conclusions, Although the precise mechanisms related to PPLAC remain to be clarified, our results indicate that the reduction in the inflammatory process as well as the antioxidant protection against deleterious elements may be considered as an integral approach to preserve the integrity of vascular endothelium, preventing the hemodynamic congestion that culminates in the formation of "dark circles" around the eyes. [source] Kynurenine inhibits chondrocyte proliferation and is increased in synovial fluid of patients with septic arthritisJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 11 2010Tim T. Lögters Abstract Kynurenine, the major degradation product of tryptophan has been shown to directly damage various tissues. Its potential contribution to septic arthritis is unknown. In this study, we analyzed the putative diagnostic value of kynurenine for bacterial joint infection and its potential harmful effects on cartilage. In a prospective study 41 patients with a joint effusion who had undergone arthrocentesis were included. Tryptophan and kynurenine levels from synovial fluid were quantified by HPLC. Diagnostic value of kynurenine was evaluated and its effects on the proliferation of the chondrocyte cell line ATDC5 were determined. Synovial fluid kynurenine values from patients with septic arthritis (4.1,±,0.8,µmol/L, n,=,9) were significantly increased compared to patients with non-infectious inflammatory arthropathy (1.8,±,0.2,µmol/L, n,=,17) or osteoarthritis (1.2,±,0.1,µmol/L, n,=,15, p,<,0.01). At a cut-off value of 2.28,µmol/L kynurenine had a sensitivity of 0.89 and a specificity of 0.87. Further, kynurenine inhibited chondrocyte (ATDC5) cell proliferation in a dose-dependent manner. Septic arthritis is associated with significantly increased values of synovial kynurenine. Furthermore kynurenine inhibits proliferation of chondrocytes, which strongly suggests a pathophysiological effect of kynurenine on cartilage in inflammatory arthropathies. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1490,1496, 2010 [source] | ||||||||||