Groundwater and surface water quality characterization through positive matrix factorization combined with GIS approach.

This study aims at testing the effectiveness of Positive Matrix Factorization in characterizing groundwater and surface water quality, in terms of identifying main hydrochemical features and processes (natural and anthropogenic) that govern them. This method is applied in a hydro-system featured by a strong interrelation between groundwater and surface water and highly impacted by agricultural activities. Therefore, a holistic approach considering groundwater together with the surface water bodies, consisting in lake, several rivers and springs, was used. Multivariate statistical analysis, in particular Factor Analysis, has been proved to be effective in elaborating and interpreting water quality data highlighting the information carried within them, but it presents some limitations: it does not consider data uncertainty and it groups variables which are correlated positively and negatively. Moreover, in some cases the resulting factors are not clearly interpretable, describing each one various overlapping features/processes. Here, Positive Matrix Factorization is applied to groundwater and surface water quality data, and the results are compared to those obtained through a Factor Analysis in terms of both factor profiles and their spatial distribution through a GIS approach. Results of isotopes analysis are used to validate PMF output and support interpretation. Positive Matrix Factorization allows to consider data uncertainty and the solution respects two positivity constraints, based on the concept of chemical mass balance, which leads to a more environmentally interpretable solution. Results show that Positive Matrix Factorization identifies five different factors reflecting main features and natural and anthropogenic processes affecting the study area: 1) surface water used for irrigation, 2) groundwater subjected to reducing processes at advanced stages, 3) groundwater subjected to reducing processes at early stages, 4) groundwater residence time and 5) the effects of the agricultural land use on both groundwater and surface water. Positive Matrix Factorization leads to a more detailed understanding of the studied system as compared to Factor Analysis which identifies only three factors with overlapping information. Based on the results of this study, Positive Matrix Factorization could be a useful technique to perform groundwater and surface water quality characterization and to reach a deeper understanding of the phenomena that govern water chemistry.

Ambient and laboratory observations of organic ammonium salts in PM1.

Ambient measurements of PM1 aerosol chemical composition at Cabauw, the Netherlands, implicate higher ammonium concentrations than explained by the formation of inorganic ammonium salts. This additional particulate ammonium is called excess ammonium (eNH4). Height profiles over the Cabauw Experimental Site for Atmospheric Research (CESAR) tower, of combined ground based and airborne aerosol mass spectrometric (AMS) measurements on a Zeppelin airship show higher concentrations of eNH4 at higher altitudes compared to the ground. Through flights across the Netherlands, the Zeppelin based measurements furthermore substantiate eNH4 as a regional phenomenon in the planetary boundary layer. The excess ammonium correlates with mass spectral signatures of (di-)carboxylic acids, making a heterogeneous acid-base reaction the likely process of NH3 uptake. We show that this excess ammonium was neutralized by the organic fraction forming particulate organic ammonium salts. We discuss the significance of such organic ammonium salts for atmospheric aerosols and suggest that NH3 emission control will have benefits for particulate matter control beyond the reduction of inorganic ammonium salts.

The ambient aerosol characterization during the prescribed bushfire season in Brisbane 2013.

Prescribed burnings are conducted in Queensland each year from August until November aiming to decrease the impact of bushfire hazards and maintain the health of vegetation. This study reports chemical characteristics of the ambient aerosol, with a focus on source apportionment of the organic aerosol (OA) fraction, during the prescribed biomass burning (BB) season in Brisbane 2013. All measurements were conducted within the International Laboratory for Air Quality and Health (ILAQH) located in Brisbane's Central Business District. Chemical composition, degree of ageing and the influence of BB emission on the air quality of central Brisbane were characterized using a compact Time of Flight Aerosol Mass Spectrometer (cToF-AMS). AMS loadings were dominated by OA (64%), followed by, sulfate (17%), ammonium (14%) and nitrates (5%). Source apportionment was applied on the AMS OA mass spectra via the multilinear engine solver (ME-2) implementation within the recently developed Source Finder (SoFi) interface. Six factors were extracted including hydrocarbon-like OA (HOA), cooking-related OA (COA), biomass burning OA (BBOA), low-volatility oxygenated OA (LV-OOA), semivolatile oxygenated OA (SV-OOA), and nitrogen-enriched OA (NOA). The aerosol fraction that was attributed to BB factor was 9%, on average over the sampling period. The high proportion of oxygenated OA (72%), typically representing aged emissions, could possess a fraction of oxygenated species transfored from BB components on their way to the sampling site.

Metabolic flux response to phosphoglucose isomerase knock-out in Escherichia coli and impact of overexpression of the soluble transhydrogenase UdhA.

Blocking glycolytic breakdown of glucose by inactivation of phosphoglucose isomerase (Pgi) in Escherichia coli led to a greatly reduced maximum specific growth rate. Examination of the operational catabolic pathways and their flux ratios using [U-(13)C(6)]glucose-labeling experiments and metabolic flux ratio analysis provide evidence for the pentose phosphate (PP) pathway as the primary route of glucose catabolism in the knock-out mutant. The resulting extensive flux through the PP pathway disturbs apparently the reducing power balance, since overexpression of the recently identified soluble transhydrogenase UdhA improves significantly the growth rate of the Pgi mutant. The presented results provide first evidence that UdhA restores the cellular redox balance by catalyzing electron transfer from NADPH to NADH.

Co-overexpression of RspAB improves recombinant protein production in Escherichia coli.

The Escherichia coli mutant CWML2 was previously reported to exhibit improved physiological characteristics, including recombinant protein production. Here we investigate the molecular basis of this phenotype by comparing the cellular level of three RNA polymerase sigma subunits by immunoblot analysis. While the level of housekeeping sigma(D) was similar in parent and mutant, the levels of the flagella synthesis regulator sigma(F) and the stationary phase regulator sigma(S) were higher in the mutant strain, indicating a different motility and stationary phase phenotype. Evidence for this conclusion was provided by the significantly higher motility of CWML2, compared to its parent. Based on these results, we hypothesized that alterations in ppGpp regulation via a homoserine lactone-dependent mechanism may be relevant for the mutant phenotype. Indeed, transcription of the rspAB operon, which was previously described to be involved in the degradation of homoserine lactone, was found to be deregulated in CWML2 in a plasmid-based reporter protein assay. By overexpression of the E. coli rspAB operon, we could partly mimic the mutant phenotype and demonstrate that co-overexpression of RspAB is a pertinent metabolic engineering strategy to improve recombinant protein production.

[Chromium and atherosclerosis]. / Cromo e aterosclerosi.

The authors report numerous experimental and clinical studies relating deficiency of chromium in the organism and atherosclerosis. They hope new researches to compute the pool of chromium in the organism and the validity and possibility to utilize this oligoelement in prevention of atherosclerosis.

[Asymptomatic microhematuria]. / La microematuria asintomatica.

Microscopic haematuria is an urinary finding more and more frequently observed in routine analysis in childhood; the diagnostic problems, most of which unresolved, are yet the principal questions of concern. We have studied 123 patients during five years from 1975 to 1980, and followed them for 1-8 years (mean 4 years). Our experience allowed us to consider "normal" or without remarkable pathologic significance a urinary finding less than or equal to 5.000 RBC/m' at the Addis count. Such findings were pointed out in 55 cases (44%); 27 patients (22%) had 5-10.000 RBC/m', 34 cases (27,6%) presented 10-50.000 RBC/m' and 7 cases (5,7%) had more then 50.000 RBC/m'. The familiar background, the clinical, biological and immunological data, the roentgenographic investigations and the renal biopsy carried out in the 4 groups of patients, led us to the following conclusions: 1) 26% of the 123 cases had a "unexplained;; microscopic haematuria with complete lack of anamnestic data, symptomatology and with normal biological findings. 2) in 65,8% of the cases it was possible to discover frequent upper respiratory tract infections (and allergy in 5,6% of them). 3) in 26% of the patients we discovered a previous or actual genito-urinary (10,5% and 15,5% respectively) infection: 9,4% of 96 urography demonstrated a variable degree of nephro-urological abnormalities. 4) 23 children (18,7%) was selected for renal biopsy, primarily by the hypocomplementemia and positive anti-DNA ab. test, and secondly by elevated degree of microhematuria. The histological and immunohistochemical studies demonstrated the presence of mesangial proliferation glomerulonephritis with IgG-IgA-C3 deposits in 7 cases (30% of the cases biopsied and 5,6% of the total), 69,6% of the cases had only minimal charges with negative immunofluorescence. 5) A mean follow-up of 4 years in two groups of patients (less than or greater than 6 years of age) has demonstrated that microscopic haematuria remains unchanged in 18-19% of both groups. A more marked improvement or normalization has been documented in the children more than 6 years aged (p less than 0,001) while a worsening has been observed in the children less than 6 years aged (p less than 0,005), with a statistically significant difference between the two groups considered.

[Diagnostic and therapeutic problems in lupus nephritis]. / Il problema diagnostico e terapeutico della lupus-nefrite.

A review of the SLE in the paediatric age in performed to underline the peculiarity of the disease in children: age, frequency, symptomatology, renal histology, clinical course, therapy and correlated side effects are reported according to literature data. The A.A. describe six cases of lupus nephritis, observed in the last few years, which confirm the diagnostic difficulties and the wide variety in the evolution of the disease. A favourable course of the disease was obtained in three cases, with corticosteroid and immuno-depressive treatment (used in association and/or alternatively); a fourth case developed some therapeutic complications among which an avascular bilateral bone necrosis, leucopenia, alopecia and herpes zoster. In two cases the SLE led to chronic renal failure owing to many relapses of the disease, enhanced by therapeutic break or dosage reduction. A careful surveillance of these patients is of fundamental importance in the management of the disease in order to obtain the longer survival and the lesser side effects.

[Medical and dietetic management of congenital and inherited nephropathies (author's transl)]. / Il trattamento medico e dietetico delle nefropatie congenite ed ereditarie.

The management of the congenital and inherited nephropathies is, still today, almost exclusively symptomatic. The authors relate the most important drugs and the dose used for the principal complications of these nephropathies: hypertension, hypo-dysprotidoemia, oedema, anemia, metabolic acidosis, polyuria, hypoevolutism, recurrent urinary infections. Particular care must be taken in order to provide an adequate caloric-protein allowance principally when the renal insufficiency is reached.