Transcriptional and physiological response of Nitrosomonas europaea to inhibition by chlorinated aromatics and heavy metals

This research investigates the physiological and transcriptional responses of Nitrosomonas europaea when exposed to chlorinated aromatic compounds and heavy metals under varying environmental conditions. It was found that transcriptional responses of identified sentinel genes correlate well with nitrification inhibition. Sorption of metals to biomass was also investigated and found not to correlate well with N. europaea inhibition. Whole genome microarray experiments were performed to define the transcriptional response of N. europaea when exposed to chlorobenzene. 13 out of 2460 N. europaea genes were significantly up-regulated after a 1-hour exposure to 4 μM chlorobenzene. HPLC analysis revealed that chlorobenzene was being oxidized primarily into 4-chlorophenol, and further physiological studies revealed that the presence of 4-chlorophenol could account for the inhibitory responses observed. RT-qPCR analysis of several differentially regulated genes verified that similar transcriptional responses were occurring for both chlorobenzene and 4-chlorophenol. 50% inhibitory concentrations of chlorobenzene and 4-chlorophenol resulted in moderate up-regulation of studied genes, however, increasing the concentration of 4-chlorophenol to achieve nitrification inhibition of 93% or more dramatically increased the fold regulation of several of the identified up- and down- regulated genes of interest. Increasing the 4-chlorophenol exposure time to 3 hours at the higher inhibition levels led to a general decrease in amplitude of transcriptional response for all genes tested. Cultures of N. europaea were exposed to various amounts of cadmium in aqueous solution containing EDTA, a strong metal-chelating organic, to control free ionic cadmium²⁺ (Cd²⁺) concentrations. Inhibition of ammonia oxidation as well as transcriptional up-regulation of merA, an identified sentinel gene for exposure to cadmium was found to correlate well with the concentration of Cd²⁺. The concentration of Cd²⁺ required to significantly affect N. europaea cells was found to be in the nanomolar range, which is several orders of magnitude lower than values reported in the literature for cadmium inhibition to mixed-culture activated sludge systems. The sorption of cadmium to the cells was found to be proportional to both the concentration of total cadmium and the concentration of Cd²⁺. At the concentration of metals required to cause approximately 50% nitrification inhibition, specific oxygen uptake results indicate the inhibition is specific to AMO with HAO and downstream energy-generation processes intact. To investigate more closely the inhibitory interactions between heavy metals and AMO, N. europaea inhibition by cadmium, zinc and silver was studied under substrate-limiting conditions. Unlike incubation in oxic environments, 1 hour incubations of N. europaea with cadmium and silver under anoxic conditions did not cause inhibition of nitrification activity after re-suspension in oxic media. In contrast, zinc, which is normally considered an analogue of cadmium in terms of toxic effect and transport mechanisms, was non-inhibitory to N. europaea when exposed in media lacking ammonia. Transcriptional response of merA closely followed the inhibition patterns, with samples which were inhibited after the removal of the metal having significant up-regulation of the gene, and those samples which were uninhibited showing no significant change in merA transcript levels compared to controls. Although sorbed metal concentrations were not found to be predictive of either extent of inhibition or transcriptional response, significantly more cadmium, zinc and silver were sorbed to biomass when incubated in aerobic media compared to anoxic media. Sorption in oxic media was found to be independent of AMO activity and similar results were obtained using Deinococcus radiodurans, a non-nitrifying gram-positive extremophile. The results indicate that greater heavy metal sorption to biomass in oxic environments may be due to general membrane chemistry effects.Keywords: Silver, Heavy metal, Nitrifier, Chlorinated aromatic, Zinc, Transcript, mRNA, Cadmium, Nitrosomonas europaea, NItrificatio

Multidimensional screening for predicting pain problems in adults : a systematic review of screening tools and validation studies

Screening tools allowing to predict poor pain outcomes are widely used. Often these screening tools contain psychosocial risk factors. This review (1) identifies multidimensional screening tools that include psychosocial risk factors for the development or maintenance of pain, pain-related distress, and pain-related disability across pain problems in adults, (2) evaluates the quality of the validation studies using Prediction model Risk Of Bias ASsessment Tool (PROBAST), and (3) synthesizes methodological concerns. We identified 32 articles, across 42 study samples, validating 7 screening tools. All tools were developed in the context of musculoskeletal pain, most often back pain, and aimed to predict the maintenance of pain or pain-related disability, not pain-related distress. Although more recent studies design, conduct, analyze, and report according to best practices in prognosis research, risk of bias was most often moderate. Common methodological concerns were identified, related to participant selection (eg, mixed populations), predictors (eg, predictors were administered differently to predictors in the development study), outcomes (eg, overlap between predictors and outcomes), sample size and participant flow (eg, unknown or inappropriate handling of missing data), and analysis (eg, wide variety of performance measures). Recommendations for future research are provided

Dental amalgam fillings: An under-investigated source of mercury exposure

Dental amalgam fillings, which contain about 50% mercury, have been used since the early 19th century. However, their use has been controversial, particularly because they continually release small amounts of mercury. Inorganic mercury is known to be highly toxic, particularly to the nervous system and kidneys, but exposures from amalgam fillings are generally well below those established as toxic. However, uncertainties about threshold concentrations of effect and the nature of any long-term exposure effects remain. Considering the long-standing and widespread use of these fillings, there has been remarkably little investigation of their safety and most epidemiologic studies have been relatively recent. In general, investigations to date have shown little evidence of effects on general chronic disease incidence or mortality. There have been few studies so far of neurodegenerative diseases and results have been equivocal. Assessments of the safety of dental amalgam have mainly been based on studies of occupationally exposed populations. However, the amalgam-exposed population contains a broader, potentially more susceptible, spectrum of people. In that regard, a number of studies of children that have found no evidence of health effects have provided some reassurance

Changes in health complaints after removal of amalgam fillings

The aim of the present study was to investigate whether removal of all amalgam fillings was associated with long-term changes in health complaints in a group of patients who attributed subjective health complaints to amalgam fillings. Patients previously examined at the Norwegian Dental Biomaterials Adverse Reaction Unit were included in the study and assigned to a treatment group (n = 20) and a reference group (n = 20). Participants in the treatment group had all amalgam fillings replaced with other restorative materials. Follow-ups took place 3 months, 1 and 3 years after removal of all amalgam fillings. There was no intervention in the reference group. Subjective health complaints were measured by numeric rating scales in both groups. Analysis of covariance was used to compare changes in health complaints over time in the two groups. In the treatment group, there were significant reductions in intra-oral and general health complaints from inclusion into study to the 3-year follow-up. In the reference group, changes in the same period were not significant. Comparisons between the groups showed that reductions in intra-oral and general health complaints in the treatment group were significantly different from the changes in the reference group. The mechanisms behind this remain to be identified. Reduced exposure to dental amalgam, patient-centred treatment and follow-ups, and elimination of worry are factors that may have influenced the results

Detection and quantification of new psychoactive substances (NPSs) within the evolved "legal high" product, NRG-2, using high performance liquid chromatography-amperometric detection (HPLC-AD)

The global increase in the production and abuse of cathinone-derived New Psychoactive Substances (NPSs) has developed the requirement for rapid, selective and sensitive protocols for their separation and detection. Electrochemical sensing of these compounds has been demonstrated to be an effective method for the in-field detection of these substances, either in their pure form or in the presence of common adulterants, however, the technique is limited in its ability to discriminate between structurally related cathinone-derivatives (for example: (±)-4′-methylmethcathinone (4-MMC, 2a) and (±)-4′-methyl-N-ethylmethcathinone (4-MEC, 2b) when they are both present in a mixture. In this paper we demonstrate, for the first time, the combination of HPLC-UV with amperometric detection (HPLC-AD) for the qualitative and quantitative analysis of 4-MMC and 4-MEC using either a commercially available impinging jet (LC-FC-A) or custom-made iCell channel (LC-FC-B) flow-cell system incorporating embedded graphite screen-printed macroelectrodes. The protocol offers a cost-effective, reproducible and reliable sensor platform for the simultaneous HPLC-UV and amperometric detection of the target analytes. The two systems have similar limits of detection, in terms of amperometric detection [LC-FC-A: 14.66 μg mL−1 (2a) and 9.35 μg mL−1 (2b); LC-FC-B: 57.92 μg mL−1 (2a) and 26.91 μg mL−1 (2b)], to the previously reported oxidative electrochemical protocol [39.8 μg mL−1 (2a) and 84.2 μg mL−1 (2b)], for two synthetic cathinones, prevalent on the recreational drugs market. Though not as sensitive as standard HPLC-UV detection, both flow cells show a good agreement, between the quantitative electroanalytical data, thereby making them suitable for the detection and quantification of 4-MMC and 4-MEC, either in their pure form or within complex mixtures. Additionally, the simultaneous HPLC-UV and amperometric detection protocol detailed herein shows a marked improvement and advantage over previously reported electroanalytical methods, which were either unable to selectively discriminate between structurally related synthetic cathinones (e.g. 4-MMC and 4-MEC) or utilised harmful and restrictive materials in their design

Blood lead, cadmium and mercury among children from urban, industrial and rural areas of Fez Boulemane Region (Morocco): Relevant factors and early renal effects

Objectives: To describe blood lead (Pb-B), cadmium (Cd-B) and mercury (Hg-B) levels in children living in urban, industrial and rural areas in Fez city (north of Morocco) and to identify the determinants and some renal effects of exposure. Material and Methods: The study was conducted from June 2007 to January 2008 in 209 school children (113 girls, 96 boys), aged 6-12 years, from urban, industrial and rural areas in Fez city. Interview and questionnaires data were obtained. Blood and urinary samples were analyzed. Results: The mean of blood lead levels (Pb-B) in our population was 55.53 μg/l (range: 7.5-231.1 μg/l). Children from the urban area had higher blood lead levels (BLLs) mean (82.36 μg/l) than children from industrial and rural areas (48.23 and 35.99 μg/l, respectively); with no significant difference between boys and girls. BLLs were associated with traffic intensity, passive smoking and infancy in the urban area. The mean of blood cadmium levels (BCLs) was 0.22 μg/l (range: 0.06-0.68 μg/l), with no difference between various areas. Rural boys had higher BCLs mean than rural girls, but no gender influence was noticed in the other areas. BCLs were associated with the number of cigarettes smoked at children's homes. The blood mercury levels (BMLs) mean was 0.49 μg/l (range: 0.01-5.31 μg/l). The BMLs mean was higher in urban and industrial areas than in the rural area with no gender-related difference. BMLs were associated with amalgam fillings and infancy in the urban area. About 8% of the children had BLLs ≥ 100 μg/l particularly in the urban area, microalbuminuria and a decrease in height were noticed in girls from the inner city of Fez and that can be related to high BLLs (89.45 μg/l). Conclusions: There is a need to control and regulate potential sources of contamination by these trace elements in children; particularly for lead

Hur kan produktdesign förbättra kommunikationen mellan grundskolelärare och elever med NPF diagnoser?

Elever med neuropsykiatriska funktionsvariationer (NPF) upplever en försämrad skolgång på grund av att den är dåligt anpassad efter deras behov. Grundskolelärare har ett ansvar att anpassa sin undervisning så den passar alla, men deras ökade belastning lämnar lite tid över till att kommunicera med sina elever på individnivå för att ta reda på deras behov. Den bristande kommunikationen mellan grundskolelärare och elever med NPF blir problematisk då parternas behov missförstås av varandra. Denna studie undersökte hur man genom produktdesign kan skapa en bättre kommunikation mellan elever med NPF och deras lärare. Studien genomfördes med teorier och metoder från forskningsfältet användarcentrerad design. Genom intervjuer, observationer, dokumentanalys, en ökad empatisk förståelse och marknadsundersökning skaffade studien en förståelse av användarnas behov och önskemål. En koncept- och produktutvecklingsfas möjliggjorde skapandet av ett slutgiltigt produktförslag. Studiens slutsats visar hur produktdesign i en användarcentrerad designprocess skapar en förståelse för en användargrupp och möjliggör ett produktförslag som tillfredsställer deras behov. Studien resulterade i ett produktförslag som kan förbättra kommunikationen mellan grundskoleelever med NPF och deras lärare. Produktförslaget kan förhoppningsvis leda till en bättre skolgång för elever med NPF om läraren gör anpassningar i sitt klassrum och/eller undervisning som tar hänsyn till elevens behov. Produktförslaget är endast ett förslag på hur en produktlösning kan se ut bland många andra möjliga lösningar. Studiens kunskapsbidrag bidrar med insikt i hur man genom produktdesign och en användarcentrerad designprocess kan utforska en användargrupp för att tillgodose deras behov.Students with cognitive disabilities are unsatisfied with their lower school education because of poor adaption to their needs. Lower school teachers have a responsibility to adjust their way of teaching and classroom environment in order to fulfill everyone’s needs. But the abundant workload teachers experience leaves little time for individual communication with their students to find out their needs. This study examined how product design can create a better communication between lower school students with cognitive disabilities and their teachers. The study used theories and methods from the research field of user-centered design. The methods used were interviews, observations, analysis of documents, improvement of empathetic understanding and a market analysis. These enabled a better understanding of the users’ needs and desires. The study’s conclusion shows how product design in a user-centered design process can create a better understanding of a user group and a design-proposal that satisfies the users’ needs and desires. The study resulted in a design-proposal that can improve communication between lower school students and their teachers. The design proposal can potentially lead to an improved education for students with cognitive disabilities if the teacher adjusts their classroom environment and/or way of teaching with regards to their students’ needs. The design-proposal is merely a proposal among many other solutions of how a product solution could be made. The study contributes with research about how product design and a user-centered design process can examine a user group in order to satisfy their needs