A series of Pt(S₂N₂)(P(OR)[subscript n]R′[subscript(3-n)])₂ complexes were prepared and analysed using ³¹P NMR and IR spectroscopy, elemental analysis and X-ray crystallography. Similarly, a series of Pt(SeSN₂)(P(OR)[subscript n]R′[subscript(3-n)])₂ complexes were also prepared and analysed. The ¹J[subscript(Pt-P)] coupling constants and Pt-P bond lengths for these complexes are influenced by the oxygen content of their phosphorus ligands. The ³¹P NMR spectra for a series of [Pt(S3N)(P(OR)[subscript n]R′[subscript(3-n)])₂][BF₄] complexes are also reported. Planar [S₂N₂H]⁻ complexes were prepared and the X-ray crystal structure of [Pd(S₂N₂H)(bipy)][Cl] is reported. The X-ray structures of MX₂(P(OR)[subscript n]R′[subscript(3-n)])₂ are reported and compared with the previously reported analogues. The magnitude of the ¹J[subscript(Pt-P)] varies linearly with the Pt-P bond length (l[subscript(Pt-P)] = 2.421 – J/24255) for the 12 platinum-containing complexes. This correlation is compared to that of a larger series of complexes. A series of M(ndsdsd₂ (ndsdsd = bis[(nitrilo(diphenyl)-λ⁶-sulfanyl)](diphenyl)-λ⁶-sulfanediimide (Ph₂S(=N-(Ph₂)S≡N)₂)) complexes were prepared and characterised using elemental analysis and multinuclear NMR and IR spectroscopy where appropriate. The X-ray crystal structures of five examples are reported.

During recent years most of the successful developments in pyrethroids have been primarily concerned with structural or compositional variations. As a part of our continuing interest in pyrethroid insecticides, nitrogen-containing compounds having pyrethroid-like structures were synthesized. Seven prolinate compounds, N-(substituted)-phenyl-prolinates and N-carbobenzoxy-prolinates were coupled with known pyrethroid alcohols. These structural variations which "locked in" a specific conformation between the nitrogen and chiral a-carbon in the acid moiety of fluvalinate were studied to determine the influence of certain conformations on insecticidal toxicity. The toxicity data for the prolinate compounds showed intermediate mortality against nonresistant cockroaches. It was concluded that the conformation imposed by the proline ring portion of the esters was probably close to the favored conformation for interaction of fluvalinate-like pyrethroids with the insect receptor site. A second series of nitrogen-containing compounds, twenty-five carbamate esters resulting from the condensation of N-isopropyl-(substituted)-anilines and N-alkyl-(substituted)-benzylamines with appropriate pyrethroid alcohols were studied for insecticidal activity. These studies were conducted on pyrethroid-susceptible houseflies. Some of the carbamate esters exhibited high toxicity when synergized by piperonyl butoxide. For example, the toxicity ( LD 50 ) of O-a-cyano-3-phenoxyfaenzyl-N-a,a-dimethyl-4-bromo-benzyl carbamate was 0.012 ug/g, which is significantly greater than that reported for the potent pyrethroid, fenvalerate. Correlations of insecticidal activity with respect to structure and conformational factors of the carbamate esters have been made. The N-isopropyl substituent decreases insecticidal activity in the N-benzyl-derived compounds, while the N-isopropyl substituent enhances activity in the N-phenyl-derived compounds. Certain substituents on the phenyl ring of both analogs greatly affect insecticidal potency of the carbamate esters. Also, some alkyl substituents (especially, a,cx-dimethyl and a-cyclopropyl groups) on the benzylic carbon of the benzylamine series enhance toxicity. The a,a-dimethyl branching of the N-benzyl carbamate approximates the steric shape given by the gemdimethyl group for conventional cyclopropane ring-containing pyrethroids. The N-benzyl compounds are significantly synergized by piperonyl butoxide, particularly those in which the carbamate nitrogen atom is mono-substituted.

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of Science in Engineering / South Africa, like many other developing countries, is faced with rapid urbanisation with the associated increase in the pollution load. Much of this pollution is destined for our watercourses, that eventually run into storage reservoirs which may be used for drinking water or recreational purposes. This pollution is usually attributed to human waste products which include nitrogenous wastes, phosphates, microorganisms, organic material and litter, A 6km stretch of the Jukskei river just downstream of Alexandra Township, was used to determine the different biological, physical and chemical processes that pollutants undergo during natural assimilation, their rates and efficiencies of assimilation in rivers and their impact Oil the environment downstream of the urban area. "Grab" samples were taken over a period which included both low-flow and storm events. Due to the high concentration of nutrients in the run-off from Alexandra Township, the major changes seen were in the biological conversion of organic nitrogen compounds and ammonia to nitrates, in the BOD and in the concentration of dissolved oxygen in the river, with lows of 1.1 to 1.5 mg/l 02 being recorded at Alexandra. A rapid rise in the concentration of faecal coliforms has been seen with a high of 31 million/100 ml being recorded at Alexandra in September, 1994. Sedimentation at the Alexandra site is also a common occurrence with a lot of adsorbed pollutants being effectively removed from the water column with the suspended solids. The QUAL2E water quality model, used by the EPA in the United States, was used to model the reactions that the nutrients, BOD and DO undergo. BOD and DO were modelled very well with r of 0.98 and 0.94 being calculated respectively. QUAL2E did not model tile dissolved potlutants, dissolved phosphorus and ammonia very well with the observed results showing a greater reduction ill these pollutants. A method by which these pollutants adhere to SS and settle out was / AC2017

O presente estudo teve como objetivo a caracterização das frações protéicas e de carboidratos em pastagem de capim-elefante (Pennisetum purpureum cv. Cameroon), manejada com altas taxas de lotação no período das águas. O experimento foi realizado nas instalações do Departamento de Zootecnia da Esalq/USP. A forragem foi coletada nas estações do outono/2006, primavera/2006 e verão/2006-07, adotando-se intervalos de desfolhação fixos de 27 dias e variáveis, onde a entrada dos animais ocorreu quando o capim atingiu 1,05 m de altura (95 % IL). Foi determinada a composição bromatológica, frações protéicas e de carboidratos tanto por métodos químicos quanto pelo método de degradação in situ da forragem. A pastagem também foi avaliada quanto à massa de forragem (kg de MS por ha-1), composição morfológica e alturas do dossel na entrada e saída dos animais. Para as determinações no pasto utilizou-se o delineamento inteiramente aleatorizado com medidas repetidas no tempo. Para as frações protéicas A, B e C, foi realizado ensaio de degradabilidade in situ utilizando-se 4 garrotes castrados e canulados no rúmen. As amostras de forragem secas e moídas a 5 mm foram acondicionadas em sacos de nylon e incubadas no rúmen por 0, 3, 6, 12, 24, 48, 60, 72, 96 e 120 horas. O delineamento experimental foi em quadrados latinos 2x2 replicados. A duração do intervalo entre desfolhas não diferiu entre os tratamentos (P>0,05), em nenhuma das estações avaliadas. As alturas do dossel no pré-pastejo foram maiores (P<0,05) nos tratamentos com ID variável. Para altura do dossel em pós-pastejo, houve efeito somente da estação (P<0,05), com menores alturas na primavera (0,43 e 0,51 m), e maiores no verão (0,56 e 0,57 m) para os tratamentos com ID fixo e variável. Não foi verificada diferença (P>0,05) para produção de forragem entre os tratamentos. Apenas os teores de PB da forragem foram afetados pelos tratamentos (P<0,05), com menores valores para ID variável. Os teores de MS, FDN, FDA, lignina e PIDA não diferiram (P>0,05) entre os tratamentos. Somente a fração protéica B2 foi afetada, com maiores valores para ID variável (P<0,05). As frações A e B3 diferiram nas estações do ano (P<0,05), com o outono apresentando menores valores de A e maiores da B3. Não houve diferença para as frações B1 e C (P>0,05). No verão, a fração A+B1 dos carboidratos apresentou os menores valores dentre as estações (13,80 e 16,22 % para ID fixo e variável), e a fração B2, os maiores valores (76,59 e 73,42 %) (P<0,05). Não houve diferenças (P>0,05) para as variáveis de degradabilidade da MS e MO. Na degradabilidade da FDN, diferenças significativas foram observadas apenas para variável de DP e DE com taxa de passagem de 2 %/h no tratamento com ID fixo. A correção da contaminação microbiana resultou em aumento nos valores da fração protéica A e redução na B. Não houve efeito (P>0,05) para as variáveis da PB corrigida pela contaminação, exceto para a fração B, onde os valores foram maiores no outono (73,3 e 73,69%) e menores na primavera com ID variáveis (55,87%). / The present study designed to characerize the protein and carbohydrate fractions of elephant grass pasture (Pennisetum purpureum) cv. Cameroon, intensively grazed at high stocking rate during the rainy season. The experiment was carried in the Animal Sciences Department of the University of São Paulo (USP/ESALQ). Forage samples were collected during autumn and spring/2006 and summer/2006-07. Two defoliation intervals (DI) were adopted, fixed and variable. For the fixed DI treatment experimental animals had access to the paddocks every 27 days, and for the variable DI treatment experimental animals had access to the paddocks when the sward reached 1,05m height, corresponding to 95% light interception. Forage samples were analyzed for chemical composition and protein and carbohydrate fractions by chemical methods and with \"in situ\" degradation technique. Pasture was also analyzed for pre-grazing forage mass (kg DM ha-1) , morphologic composition, pre and post grazing sward heights. A completely randomized design with repeated measures was used for pasture determinations. For protein fractions (A, B, C) determinations, an in situ trial was developed using four rumen canulated steers. 5mm ground forage samples were conditioned in nylon bags and incubated in the rumen for 0, 3, 6, 12, 24, 48, 60, 72, 96 and 120 hours. The experimental design was a replicated 2x2 Latin square. The defoliation interval length did not differ (P>0,05) among treatments, in any season. Pre-grazing sward heights were higher (P<0,05) for the variable DI treatment. A season effect (P<0,05) was observed for post-grazing heights, with lower values observed on spring (0,43 and 0,51m) and higher on summer (0,56 and 0,57m) for both treatments. No differences (P>0,05) were observed among treatments for total forage mass. Only forage CP content was affected by treatments, with lower values (P<0,05) for variable DI. DM, NDF, ADF, lignin and ADIN were not different (P>0,05) among treatments. Protein B2 fraction was affected, showing higher values (P<0,05) for variable DI treatment. Fractions A and B3 were different among seasons, with lower fraction A and higher fraction B3 values during autumn (P<0,05). No differences were observed for fractions B1 and C (P>0,05). During summer carbohydrate fractions A + B1 showed the lowest values among seasons (13,80 and 16,22% for fixed and variable DI), and B2 fraction showed the highest values (76,59 and 73,42 %) (P<0,05). No differences were observed for DM and OM degradabilities variables (P>0,05). For NDF degradability significant differences were observed only PD and ED variables with 2%/h passage rate for fixed DI treatment. Microbial contamination adjustment resulted in higher protein A and lower protein B fraction values. No effects were observed (P>0,05) for microbial contamination adjusted CP variables, except for B fraction that showed higher values during autumn (73,3 and 73,69%) and lower during spring with variable DI (55,87%).

A área de estudo deste trabalho, localizada no Município de Cubatão, abrange um terreno industrial desativado onde no passado foram descartados resíduos, bem como, manipulados e estocados materiais com elevados teores de substâncias orgânicas e iônicas. Por esse motivo constitui-se num sistema bastante complexo para disponibilidade iônica ao meio ambiente. Foram definidas quatro Áreas (A, B, C e D) para amostragens de solo e água subterrânea e efetuadas análises texturais , mineralógicas e químicas. Os resultados analíticos das águas subterrânea e superficial dos outros setores da área de estudo, bem como os dados utilizados para elaboração do modelo matemático e interpretação dos testes de permeabilidade foram cedidos por uma empresa de consultoria ambiental. Nas Áreas B, C e D as águas subterrâneas apresentam-se contaminadas com íons Pb e Ni ultrapassando os valores orientadores da CETESB. A presença de Al e Fe na água subterrânea, apesar dos valores de pH incompatíveis, encontram-se na forma aquosa de \'Al(OH) IND.3\' e \'Fe(OH) IND.3\' e iônica devido o elevado conteúdo iônico graças ás atividades industriais. A amônia foi identificada na água subterrânea em concentrações acima do limite estabelecido pela Portaria 518 do Ministério da Saúde em boa parte da área de estudo. Quando dissolvida na água subterrânea a amônia forma íons amônio, que sofrem adsorção junto às partículas do solo. Além de ser solúvel em água o \'NH4 POT.+\' é envolvido no processo biológico de fixação do nitrogênio, assim como na sua mineralização e nitrificação. O nitrato apresentou valores acima do limite de intervenção da CETESB em poços localizados nas Áreas B e C, a concentração de nitrito, por sua vez, foi insignificante, por ser um ânion bastante instável oxidando-se a nitrato. A condutividade hidráulica média na área de estudo é de 4,7 x \'10 POT.-4\' cm/s. Elaborou-se um modelo matemático interpolando dados de condutividade hidráulica e de análise químicas permitindo definir que o fluxo subterrâneo principal segue no sentido oeste, em direção ao Rio Perequê. Os resultados do modelo sugerem que o aporte de água com concentrações acima dos padrões adotados para amônia do aqüífero para o rio tende a sofrer declínio até extinção num período de 10 anos. Em função da dimensão atual da pluma e dos níveis de concentrações observados, a modelagem indicou que a pluma com concentrações acima do limite de intervenção não é extinta ao passar de 20 anos (final do período simulado), porém deixando de atingir o Rio Perequê antes de passados 15 anos. Como resultado deste trabalho é recomendado que a remediação do impacto causado pelos íons metálicos na água subterrânea podem ser obtida pela fixação de Pb e Ni nas formas de sulfato e óxidos/hidróxidos de chumbo e hidróxidos de níquel. No caso dos compostos nitrogenados em especial o amônio, é recomendada a biorremediação para induzir a nitrificação e posterior denitrificação, através de técnicas tais como biosparging (injeção de oxigênio), MRZ (Zona de Reação Microbial), fitoremediação e barreira reativa. / The study area of this work, located in the Cubatão city, is an industrial deactivated land where in the past were undergrounded residuals, as well as were manipulated and kept high percentage of organic and ionic substance materials. It became, for that reason, a very complex system for ionic availability to environment. Four areas (A, B, C, and D) were defined for soil and groundwater sampling, and were made textural, mineralogical, and chemical analysis. Analytical results of ground and superficial water, as well as data used for elaboration of a mathematical model and for interpretation of permeability tests of the remaining part of the study area, were facilitated by a private company of environment consultancy. Groundwater in Areas B, C, and D shows contamination with Pb and Ni ions overtaking CETESB standard values. The presence of Al and Fe in groundwater, despite of incompatible pH values, are found in a liquid form of \'Al(OH) IND.3\' and \'Fe(OH) IND.3\', and ionic, due to high content owing to the industrial activities. Ammonia was indentified in groundwater in larger concentrations than the limit established by Portaria 518 do Ministério da Saúde in a larger portion of the study area. Ammonia forms ions ammonium when dissolved in groundwater that suffers adsorption with the soil particles. Besides being soluble in water the \'NH4 POT.+\' is involved into biological processes of nitrogen fixation, as well as in its mineralization and nitrification. In wells localized in Areas B and C, nitrate presented higher values them than the limit established by CETESB. Nitrite concentration is insignificant, by being quite instable oxidizing to nitrate. Mean hydraulic conductivity in the study area is 4,7 x \'10 POT.-4\' cm/s. A mathematical model was elaborated by hydraulic conductivity dates interpolations and by chemical analyses defining the mean underground flow follows to the west, towards the Perequê River. The model results suggest that the water flow with ammonia concentration larger than the allowed standard, from the aquifer to the river tends to decline until extinction in a 10 years period. By considerer the present plum dimension and the observed concentration levels the modeling indicated that plum with the concentrations larger than the allowed limit is not extinct in 20 years (the end of the simulated period), however, without reaching the Perequê River before 15 years. As a result of this work it is recommended that the remediation of impact provoked in groundwater by the metallic ions could be obtained by fixing Pb and Ni in the sulfate and oxides/hydroxides form of lead and nickel hydroxides. In the case of nitrogen compounds, especially ammonia, it is recommended the bioremediation for inducing the nitrification, and later denitrification, through to techniques such as biosparging (oxygen injection), MRZ (Microbial Reaction Zone), Fitoremediation and reactive barrier.

No description available.

No description available.

Nitrochemicals are currently widely used as solvents, drugs, biocides, fuels and explosives and are consequently widely distributed in the environment. The reductive nitrite elimination from explosive compounds is catalyzed by two FMN-dependent, xenobiotic reductases (XenA or XenB). These genes for these regiospecific enzymes were cloned from Pseudomonas putida and P. fluorescens I-C respectively and isolated from the soil of a contaminated World War II munitions manufacturing plant. These enzymes enable the microbes to fulfill their nitrogen requirements from nitroglycerin by catalyzing the regiospecific, NADPH dependent, reductive denitration of nitroglycerin with differing selectivities. The two enzymes also transform a number of additional nitrocompounds in vitro, e.g. TNT and metronidazole, a leading drug in the treatment of Helicobacter pylori, a causative agent of human ulcers. Single crystals were obtained for XenA and XenB and complete X-ray diffraction datasets have been collected and analyzed to better understand these characteristics. The 1.6 Å resolution structure of XenA reveals a dimer of β/α)₈-TIM barrels, but the 2.3 Å resolution structure for XenB is a monomer. The (β/α)₈-TIM barrel protein fold is the most common fold in the PDB. However, the XenA structure exhibits a unique, C-terminal domain-swapped topology. Thus a portion of each active site is comprised of residues from the neighboring monomer. To probe the reaction cycle, crystal structures of ligand complexes and the reduced enzyme have been refined. For example, our structure of the XenA-metronidazole complex shows that ligands bind parallel to the FMN si-face. Our 1.5 Å resolution structure for reduced XenA reveals an FMN isoalloxazine ring with an angle of ~165° along the N5-N10 axis. We have also generated models of the reduced enzyme-nitroglycerin complexes by molecular dynamics. The results with both XenA and XenB reveal differences in enzyme-ligand hydrogen bonding. These differences correlate remarkably well with the regiospecific differences observed for nitrite elimination from nitroglycerin and reduction of TNT by the two enzymes.

Troger's base was the first amine to be resolved where the chirality was due to solely very high inversion barrier around nitrogen atom. Though the molecule was known for over a century, work done during the past decade has shown that Troger's base and its analogues could be used as chiral solvating agent, DNA binding ligand and for the construction of biomimetic molecular receptors and clathrare hosts. Asymmetric synthesis of the Troger’s base analogues has also been achieved recently. Because of the rigid, 'V'-shaped chiral nature of this molecule, there is growing interest for the use of this unit in the design of potential host systems. This section briefly describes the chemistry of Troger's base developed over a century.

The conversion of coal and char nitrogen has been investigated during fuel rich combustion. The experiments were done with the objective of clarifying the roles of NO, HCN, and NH₃, and char nitrogen in the post-combustion gases in the first, fuel rich stage of a staged combustor. The experimental apparatus includes a downflow combustor of 15 cm internal diameter and 180 cm length constructed of fibrous alumina insulation surrounding a central tube composed of vacuum- formed alumina cylinders. The combustion gases and solids were sampled in situ with a water-cooled and -quenched probe. Neither the combustor nor the sample probe were found to be reactive towards NO. Temperatures of the gases and walls were measured with Type K thermocouples and the particle temperatures were determined with a seven wavelength infrared pyrometer. Gas compositions were measured chromatographically using a 5A molecular seive for permanent gases (H₂, O₂, N₂, CO, and CH₄) and Poropak T for polar gases (CO₂ and HCN). A chemiluminescent analyzer measured NO. NH₃ and HCN were measured in the quench water with ion electrodes. The C, H, N, ash compositions of the char were measured with an elemental analyzer. Experiments of the fuel rich conversion of char nitrogen show that at all stoichiometries (SR = 0.8, 0.4) the concentrations of HCN and NH₃ in the post-flame gases are small compared to the concentration of NO. Char nitrogen conversion was stoichiometric or greater. NO destruction was found to be controlled by a heterogeneous mechanism involving the char carbon surface. The mechanism is deactivated by oxygen, an effect demonstrated by others. The fuel rich conversion of coal nitrogen was investigated with a Utah bituminous coal. At moderate fuel rich conditions (SR = 0.8), the residual char nitrogen conversion is 90 percent or greater and NH₃ and HCN concentrations were less than 20 ppmv. NO peaked at 1200 ppmv (1850 K) and declined to 600 (1580 K) ppmv over 1.8 seconds. Coal nitrogen conversion is dominated by NO formation at this stoichiometry. At extreme fuel rich conditions (SR = 0.4), coal nitrogen conversion is 85 percent. The gas is dominated by HCN, NO, and NH₃. HCN decayed from 600 ppm to 300 ppmv, NO from 350 to 50, and NH₃ increased from 200 to 375 ppmv, indicating that interconversion reactions in the gas phase are dominating. The kinetics which govern the volatile nitrogen reactions can be described by global homogeneous kinetics as follows: UNFORMATTED TABLE/EQUATION FOLLOWS: r₁ = d/dt[HCN] = -5.5x10¹⁷ exp(-83.3 K/RT)[HCN][H₂O]/[H₂]¹/² mole/cm³s r₂ = d/dt[NO] = -2.2x10¹⁶ exp(-54.4 K/RT)[NO][NH₃]/[H₂]¹/² d/dt[NH₃] = d/dt[NO] - d/dt[HCN] UNFORMATTED TABLE/EQUATION ENDS These yield rates for free radical reactions very similar to those determined in gas flame experiments, lending credence to their validity. A one-dimensional combustor model has been formulated which accounts for the heterogeneous combustion and gasification of the coal and char. This model includes the devolatilization of the coal and homogeneous oxidation of carbon monoxide and devolatilized species. The water-gas shift reaction is assumed to be equilibrated. The model also includes the mass, momentum and energy balances of the particles but obviates the solution of the combustor heat balance by using the measured gas temperature in the solution. The model accurately predicts the gas and elemental conversions and particle temperatures observed in the experiments, and supports the homogeneous and heterogeneous kinetics of post-combustion fuel nitrogen conversion.