Research report on the dynamics of nitric compounds in different water levels of shallow wells, located in Pypliai, Kaunas District, is given in the thesis. Subject of research – water quality indicators: nitrates (NO3-), nitrites (NO2-) and ammonium (NH3). Aim of research – to define variation of nitrates concentrations in different water levels of shallow wells. Methodology: analysis of scientific literature; chemical water quality analyzes methods: spectral and electrochemical methods; statistical analysis using EXCEL, STATISTICA programs. Results of research: the results of scientific research showed, that nitrates concentrations in deeper levels of shallow wells vary differently; the tendencies of these variations depend on seasons. Seasons make no impact to nitrites and ammonium concentrations in deeper levels of shallow wells. The following statistically relevant water indicators were determined to influence nitrate concentration in shallow well water: oxygen quantity and electrical conductivity. Nitrite concentrations are inversely proportional to oxygen amount. Ammonium concentrations depend on organic compound quantity. Statistically relevant links between nitrites and ammonium were estimated.

Antibacterial effectiveness in vitro of the original quaternary ammonium compounds that were synthesized in the Laboratory of Biologically active substances was determined and the dependence of this activity upon chemical structure of the compound was established. Also generalisations have been made concerning the regularity of this dependency, the effectiveness of the compounds was compared to benzalkonium chloride, their advantages and disadvantages were discussed. Acute toxicity of the most effective compound was established and compared to that of benzalkonium chloride. It was found that these compounds showed good antibacterial activity against Gr+ and Gr- bacteria and low toxicity, thus this original data was summarized in the patent Nr. 4712. For the first time it was found that upon disintegration of quaternary methenamonium compounds new quaternary ammonium compounds, aldehydes and ammonia are produced. The first two of the three show further antimicrobic activity. Using quaternary ammonium salts and cholrhexydine a biocide for disinfection was created. The created biocide was tested for effectiveness when used for disinfection of air in the premises, horizontal and vertical surfaces. The compound was used in the form of aerosols and electro-aerosols. The research data showed that strong concentrations of Dezinfektas IV are necessary (up to 30%), but small amount of the solution per volume is enough (20-30 ml/m3). Ten times higher concentration is needed for... [to full text]

The objective of the present work was systematic investigation of water-based headspace single-drop microextraction (SDME) technique, its conjunction with capillary electrophoresis, and application for the analysis of volatile inorganic compounds (cyanide and ammonium) in biomedical and environmental samples. Theoretically evaluated and experimentally confirmed that the manipulation in the volatility of the analyte by its chemical modification in the sample and/or in the acceptor phase is the most effective way to enhance the extraction performance in headspace SDME. Maximum extraction efficiency for cyanide was observed in the pH range 4.5–7.5, where cyanide anion is completely transferred into volatile HCN. Complete cyanide recoveries (≥96%) from metal-cyanide complexes were obtained by using two ligand-exchange reagents (ethylenediamine and dithizone). Maximum extraction efficiency was observed by the extraction of ammonia from alkaline samples (pH≥11) with neutral or slightly acidic acceptor phase (pH 3-7). Compared to existing methods water-based headspace SDME is significantly faster and simpler. In addition, proposed technique does not require any sample pre-treatment (deproteinization, acidic/alkaline distillation, etc.) and thus is much less susceptible to interferences. Finally, it offers possibility to choice of a wider variety of solvents and, consequently, enhances the range of extractable analytes as well as the range of analytical methods that can be coupled... [to full text] / Daktaro disertacijoje nuodugniai ištirtas mikroekstrakcijos iš viršerdvės vandens lašu metodas, apjungtas su kapiliarine elektroforeze bei pritaikytas lakių neorganinių junginių (cianido ir amonio) koncentravimui ir nustatymui biomedicininiuose ir aplinkos objektuose. Teoriniais skaičiavimais parodyta ir eksperimentiškai patvirtinta, kad efektyviausias būdas mikroekstrakcijos iš viršerdvės efektyvumui pagerinti – analitės lakumo didinimas chemiškai modifikuojant ją prieš ekstrakciją ir/arba jos lakumo mažinimas modifikuojant ją akceptorinėje fazėje. Maksimalus cianido mikroekstrakcijos efektyvumas pasiekiamas pH srityje 4,5- 7,5, kur cianidas kiekybiškai pervedamas į lakų HCN. Ištyrus cianido mikroekstrakciją tirpiklio lašu iš metalų cianidinių kompleksų tirpalų nustatyta, kad kiekybiškas silpnai surišto cianido suardymas (cianido išgavos siekia ≥96%) pasiekiamas panaudojus ligandų mainus etilendiamino ir ditizono mišiniu. Maksimalus amonio mikroekstrakcijos efektyvumas pasiekiamas ekstrahuojant jį iš pašarmintų mėginių (pH≥11) akceptorine faze, kurios pH 3-7. Lyginant su standartiniais metodais, siūlomas metodas yra greitesnis ir paprastesnis, visiškai eliminuojama mėginio matricos įtaka, nereikalingos jokios drastiškos (deproteinizacija, veikimas rūgštimis/šarmais, distiliacija ir pan.) manipuliacijos su mėginiu, todėl išvengiama mėginio matricos įtakos. Mikroekstrakcija iš viršerdvės vandens lašu praplečia mikroekstrakcijos metodų taikymo sritis: atveriama galimybė labai... [toliau žr. visą tekstą]

The pathway of seawater ammonium assimilation and influence of light on amino acid synthesis remain unresolved in cnidarian symbioses. Labeled ammonium (10 μM 15NH4Cl) in seawater was used to trace the pathway of the incorporation into amino acids in host tissue, Zoanthus sp., and zooxanthellae, Symbiodinium microadriaticum. Freshly isolated zooxanthellae were exposed to 20 μM 15NH4Cl with coral homogenate to evaluate the role of host factors on amino acid synthesis. High performance liquid chromatography and mass spectrometry was used to measure percent labeling and concentrations of amino acids. In zooxanthellae, ammonium was assimilated into glutamine likely via glutamine synthetase and into glutamate via glutamine 2-oxoglutarate amidotransferase. Interrupting photosynthesis with DCMU did not inhibit glutamine and tryptophan synthesis however reduced the 15N-enrichment of glutamate, aspartate, and ornithine in zooxanthellae, as well as arginine, ornithine, and lysine in host tissue. Coral homogenate had little effect on the 15N-enrichment of glutamine, aspartate, and alanine in freshly isolated zooxanthellae. Evidence is presented to support the uptake of ammonium ions and data shows that glutamine and not glutamate is translocated to the coral host.

This thesis tested the hypothesis that nitrogen use efficiency of subirrigated potted chrysanthemum (Chrysanthemum morifolium Ramat.) can be improved by managing the NO3- status of the plant. Replacement of NO3- with water one week prior to flower development was the most effective method of reducing tissue NO3- content and improving the nitrogen usage index, as compared to various combinations of NO3- and Cl-. Shoot or flower dry mass and N content were unaffected and the medium electrical conductivity was reduced. Supplying N in the NH4+ form in combination with NO3- did not affect nitrogen use indices. Reducing N supply improved various indices of nitrogen use efficiency, with a slight loss of quality. Elimination of NO3- prior to flower development and reduction in N supplied are effective strategies for improving nitrogen use efficiency in subirrigated potted chrysanthemums without sacrificing quality. / Cecil Delworth Foundation

For over a decade, diquaternary ammonium gemini surfactants have shown promise as non-viral gene delivery agents in both in vitro and in vivo systems. Their continued development, however, requires an understanding of their biological fate. The absence of identification and quantification methods that can achieve that goal is what drove the development of simple and rapid mass spectrometry (MS)-based methods; the focus of my Ph.D. dissertation. Prior to the development of these MS-based methods, an understanding of the gas phase behavior of diquaternary ammonium gemini surfactants is required. The development of a universal fragmentation pathway for gemini surfactants was achieved using low resolution and high resolution MS instruments. Single stage (MS), tandem stage (MS/MS and quasi-multi-stage (quasi MS3) mass spectrometry analysis allowed for the confirmation of the molecular composition and structure of each gemini surfactant through the identification of common and unique mass to charge values. Understanding the fragmentation behavior allowed for the specific identification and/or quantification of gemini surfactants by MS-based methods; including liquid chromatography low resolution tandem mass spectrometry (LC-LR-MS/MS), fast chromatography low resolution tandem mass spectrometry, fast chromatography high resolution mass spectrometry, desorption electrospray ionization low resolution mass spectrometry and matrix assisted laser desorption ionization high resolution mass spectrometry. We hypothesized that a LC-LR-MS/MS method would be the most effective quantitative method for the quantification of N,N-bis(dimethylhexadecyl)-1,3-propane-diammonium dibromide (G16-3) within PAM212 cellular lysate; achieving the lowest lower limit of quantification (LLOQ). Although the LC-LR-MS/MS method achieved a LLOQ suitable for analysis of G16-3 within PAM212 cell lysate, its limitations made it an inefficient method. In comparison, the four alternative mass spectrometry methods were faster, more efficient and less expensive than a conventional LC-LR-MS/MS method for the post transfection quantification of G16-3 within PAM212 cell lysate to be determined; 1.45 ± 0.06 μM. Future application of the universal fragmentation pathway and each MS-based quantification method will be beneficial for the future development of diquaternary ammonium gemini surfactants to further understand their post transfection fate.

No description available.

Fertilizer P fixation and fertilizer N losses in soils may be reduced through additions of polyphenolic compounds. The influence of ammonium lignosulfonate (NH$ sb4 sp+$-LS) on triple superphosphate (TSP) efficiency was investigated in a soil incubation study using three Quebec soils and in a growth bench study using one soil. For the incubation study, soils were analyzed for pH and P extractability, as a function of NH$ sb4 sp+$-LS rate and time. In the growth bench study, TSP and NH$ sb4 sp+$-LS were applied at varying rates and corn (Zea mays L.) dry matter yields and nutrient compositions analyzed. Similar studies were conducted in subsequent growth bench studies, to evaluate combinations of NH$ sb4 sp+$-LS, diammonium phosphate (DAP), and urea on two soils. / Ammonium LS increased soluble P levels when applied with TSP. The effect was most significant in fine textured soils, and increased with time. This improved P availability to plants, without affecting growth. The optimum NH$ sb4 sp+$-LS:P$ sb2$O$ sb5$ application ratio was approximately 2.8:1. Ammonium LS did not improve availability of DAP-P in either of the subsequent experiments, nor did it improve urea fertilizer efficiency. Some NH$ sb4 sp+$-LS-urea-DAP formulations did, however, improve corn growth beyond that obtained when only urea and DAP were applied in combination. In nutrient amended soils, applying NH$ sb4 sp+$-LS DAP was detrimental to growth and, for some application rates, reduced nutrient uptake.

Benzalkonium chlorides (BACs) are widely used, broad-spectrum disinfectants and frequently detected in the environment, even at toxic levels for life. Since such disinfectants can induce broad resistance capabilities, BACs may fuel the emergence of antibiotic resistance in the environment. A substantial body of literature has reported that exposure to BACs causes antibiotic resistance; yet, other studies suggest that the resistance linkage is rare, unsystematic, and/or clinically insignificant. Accordingly, whether or not disinfectant exposure mediates antibiotic resistance and, if so, what molecular mechanisms underlie the resistance link remains to be clearly elucidated. Further, understanding how microbial communities degrade BACs is important not only for alleviating the possible occurrence of antibiotic resistance but also reducing the potential risks to environmental and public health. An integrated strategy that combines metagenomics, metatranscriptomics, genetics, and traditional culture-dependent approaches was employed to provide novel insights into these issues. The integrative approach showed that a microbial community exposed to BACs can acquire antibiotic resistance through two mechanisms: i) horizontal transfer of previously uncharacterized efflux pump genes conferring resistance to BACs and antibiotics, which were encoded on a conjugative plasmid and co-selected together upon BACs and ii) selective enrichment of intrinsically multi-drug resistant organisms. Further, a microbial community adapts to BAC exposure via a variety of mechanisms, including selective enrichment of BAC-degrading species and amino acid substitutions and horizontal transfer of genes related to BAC resistance and degradation. The metatranscriptomic data suggests that the BAC-adapted microbial community metabolized BACs by cooperative interactions among its members. More specifically, Pseudomonas nitroreducens cleaved (i.e., dealkylated) BACs, metabolized the alkyl chain (the dealkylated product of BACs), and released benzyldimethylamine (the other product of BACs), which was further metabolized by other community members (e.g., Pseudomonas putida). Collectively, this study demonstrates the role of BACs in promoting antibiotic resistance and advances current understanding of a microbial community degrading BACs. The results of this work have important implications for (appropriate) usage of disinfectants and for assessing, predicting, and optimizing biological engineering processes treating BAC-bearing waste streams.

Acrylic bone cements are one of the most important biomaterials used in orthopaedic surgery and dental applications to fill the cavities or provide mechanical interlock between prosthesis and the bone. Their biocompatibility can be increased by addition of different materials into the formulation, such as hydroxyapatite. Besides all the advantages, bone cements have several drawbacks including tissue necrosis, chemical necrosis, shrinkage of the cement and aseptic loosening. Therefore painstaking research and study are carried out on development of new formulations to improve mechanical and thermal properties as well as biocompatibilities. In this study, bone cements with different compositions were prepared and new formulations were examined to improve mechanical properties and to reduce maximum curing temperature. It was observed that addition of hydroxyapatite, while keeping polymer-to-monomer ratio constant at 2.0, decreased curing temperature and increased compressive strength about 11% (Group-C) when hydroxyapatite addition was 12%. Further addition of hydroxyapatite destroyed homogeneity of the cement dough and made it difficult to handle. The composition which contains 8% hydroxyapatite was chosen as the optimum composition in respect of mechanical properties with 102.62&deg / C curing temperature. In order to decrease the curing temperature ammonium nitrate this gives endothermic reactions with water, was added into the formulations. Addition of 0.5 g NH4NO3 decreased curing temperature from 94&deg / C to 79.3&deg / C while compressive strength kept in acceptable range with 95.99 MPa. Experiments demonstrated that the proposed formulation is acceptable for workability, homogeneity, mechanical strength and thermal properties. Further studies especially on curing temperature and biocompatibility should be achieved.