Symposium on new methods of determining biogenic and organic substances in water and organisms

Hydrobiologia ◽  
1965 ◽  
Vol 26 (1-2) ◽  
pp. 121-130 ◽  
Author(s):  
H. L. Golterman ◽  
H. R. Krause ◽  
D. F. Westlake
Author(s):  
N. S. Loboda ◽  
О. V. Smalii ◽  
І. V. Katynska ◽  
О. M. Kotovich

The relevance of the problem consists in the need to achieve a "good status" of water in the rivers of Ukraine according to the objectives of the Water Framework Directive. The aim of the work is to identify the main trends of water quality changes over time and along the length of Siverskyi Donets River based on data of the hydrochemical observations for the period from 1985 to 2015 inclusive. To establish the water quality we used integral assessments based on hydrochemical indicators such as pollution coefficient, water pollution index, generalized index of water state in accordance with the water quality standards for fishery. The article shows that use of mandatory (priority) chemical indicators in the calculations of the pollution coefficient and the water pollution index does not reflect a real degree of water pollution, since it does not take into account a significant amount of pollutants. It was discovered that major pollutants in the main river include suspended substances, chromium, nitrite nitrogen, phenols, sulfates. For the right-bank tributaries of Siversky Donets (illustrated by the example of the Kryvyi Torets River) originating from Donetsk Upland heavy metals (chromium, copper, zinc) pollution is typical. The degree of pollution based on the coefficient of pollution for average multi-year period is deemed as catastrophic, and based on the index of water pollution it is labelled with IV (contaminated) and V (very contaminated) quality classes indicating a violation of the ecosystem stability. Based on the generalized index, the water is also classified as "contaminated". The calculations based on various integral indicators of water quality revealed that pollution of the Siversky Donets River increases downstream. This is due to growing anthropogenic impact (municipal and industrial waters of large cities, discharge of mine and open pit waters into surface waterways, withdrawal of the runoff for its redirection to canals and water conduits, presence of diffuse sources of pollution by biogenic and organic substances). The beginning of the 21st century saw a trend towards improvement established in the chronological course of integral indicators of water quality which was associated with decrease production volumes. According to the generalized index of water state the water quality of the main river gradually changes from “contaminated” and “very contaminated” to “moderately contaminated”, but contamination by heavy metals, biogenic and organic substances remains high.


2014 ◽  
Vol 40 (3) ◽  
pp. 29-42 ◽  
Author(s):  
Mariusz Kuglarz ◽  
Klaudiusz Grübel ◽  
Jolanta Bohdziewicz

Abstract The aim of the study was to develop an effective treatment of post-digestion liquors highly-loaded with biogenic and organic substances. The scope of the research project encompassed: mesophilic anaerobic digestion of waste activated sludge (WAS) as well as the treatment of post-digestion liquors, coming from the most appropriate HRT value of 25 days, in the process of ammonium magnesium phosphate (struvite) precipitation targeted at ammonia nitrogen binding and a subsequent reverse osmosis (RO) process. It was established that the method combining chemical precipitation and high-pressure filtration ensures a high degree of contaminants removal allowing for a direct release of treated liquors into the natural reservoir. However, in order to decrease the residual NH4+ concentration (6.1 mg NH4+/dm3) in the purified post-digestion liquors below the level allowing for a direct release to the natural reservoir, it turned out to be necessary to apply increased molar ratio of magnesium and phosphates (Mg:NH4+: PO43-= 1.5:1:1.5).


Author(s):  
S. Basu ◽  
D. F. Parsons

We are approaching the invasiveness of cancer cells from the studies of their wet surface morphology which should distinguish them from their normal counterparts. In this report attempts have been made to provide physical basis and background work to a wet replication method with a differentially pumped hydration chamber (Fig. 1) (1,2), to apply this knowledge for obtaining replica of some specimens of known features (e.g. polystyrene latex) and finally to realize more specific problems and to improvize new methods and instrumentation for their rectification. In principle, the evaporant molecules penetrate through a pair of apertures (250, 350μ), through water vapors and is, then, deposited on the specimen. An intermediate chamber between the apertures is pumped independently of the high vacuum system. The size of the apertures is sufficiently small so that full saturated water vapor pressure is maintained near the specimen.


Author(s):  
Earl R. Walter ◽  
Glen H. Bryant

With the development of soft, film forming latexes for use in paints and other coatings applications, it became desirable to develop new methods of sample preparation for latex particle size distribution studies with the electron microscope. Conventional latex sample preparation techniques were inadequate due to the pronounced tendency of these new soft latex particles to distort, flatten and fuse on the substrate when they dried. In order to avoid these complications and obtain electron micrographs of undistorted latex particles of soft resins, a freeze-dry, cold shadowing technique was developed. The method has now been used in our laboratory on a routine basis for several years.The cold shadowing is done in a specially constructed vacuum system, having a conventional mechanical fore pump and oil diffusion pump supplying vacuum. The system incorporates bellows type high vacuum valves to permit a prepump cycle and opening of the shadowing chamber without shutting down the oil diffusion pump. A baffeled sorption trap isolates the shadowing chamber from the pumps.


Author(s):  
Dai Dalin ◽  
Guo Jianmin

Lipid cytochemistry has not yet advanced far at the EM level. A major problem has been the loss of lipid during dehydration and embedding. Although the adoption of glutaraldehyde and osmium tetroxide accelerate the chemical reaction of lipid and osmium tetroxide can react on the double bouds of unsaturated lipid to from the osmium black, osmium tetroxide can be reduced in saturated lipid and subsequently some of unsaturated lipid are lost during dehydration. In order to reduce the loss of lipid by traditional method, some researchers adopted a few new methods, such as the change of embedding procedure and the adoption of new embedding media, to solve the problem. In a sense, these new methods are effective. They, however, usually require a long period of preparation. In this paper, we do research on the fiora nectary strucure of lauraceae by the rapid-embedding method wwith PEG under electron microscope and attempt to find a better method to solve the problem mentioned above.


2019 ◽  
Vol 3 (6) ◽  
pp. 707-711 ◽  
Author(s):  
Andrew Peterson ◽  
Adrian M. Owen

In recent years, rapid technological developments in the field of neuroimaging have provided several new methods for revealing thoughts, actions and intentions based solely on the pattern of activity that is observed in the brain. In specialized centres, these methods are now being employed routinely to assess residual cognition, detect consciousness and even communicate with some behaviorally non-responsive patients who clinically appear to be comatose or in a vegetative state. In this article, we consider some of the ethical issues raised by these developments and the profound implications they have for clinical care, diagnosis, prognosis and medical-legal decision-making after severe brain injury.


2000 ◽  
Vol 12 (4) ◽  
pp. 380-380
Author(s):  
Kazuei Ogoshi ◽  
Taiji Akamatsu ◽  
Hiroyasu Iishi ◽  
Daizo Saito ◽  
Nobuhiro Sakaki ◽  
...  
Keyword(s):  

2011 ◽  
Vol 44 (8) ◽  
pp. 14-15
Author(s):  
MARY ANN MOON
Keyword(s):  

Crisis ◽  
2013 ◽  
Vol 34 (4) ◽  
pp. 289-292 ◽  
Author(s):  
Laurent Auzoult ◽  
Sid Abdellaoui

Background: Suicide prevention is a major challenge for penal institutions in many countries. The traditional approach relies on the expertise of health professionals and is supplemented by the intervention of other professionals and the inmates themselves. New methods of suicide prevention based on peer support have been developed in recent years. Peer prevention programs rely on the ability of inmates to identify suicide risk. Aims: This study examines perceived suicide risk among inmates and explores possible explanations. Method: 54 inmates and 17 professionals working in prisons responded to a questionnaire. Results: The peer prevention program was found to change inmates’ expectations of support in the event of a suicide crisis. The study also found that the inmates involved in the program tended to underestimate the risk of suicide. The perception of the prevention program and the level of self-consciousness were found to account for the underestimation of suicide risk. Conclusions: Support for inmates involved in suicide prevention programs must take into account their isolation in prison. The training provided to inmates must also consider the biases affecting the assessment of risk.


Sign in / Sign up

Export Citation Format

Share Document