Coupling of photocatalysis and catalysis using an optical fiber textile for room temperature depollution.

Herein, we investigate the interplay between a photocatalyst (TiO2) and a catalyst (Pt/TiO2 and Pt/CeO2) for the oxidation of formaldehyde and toluene at room temperature. A luminous textile is used as support and as light source for the photocatalyst. Our results indicate that the presence of the catalyst and the photocatalyst increases the catalytic performance for the oxidation of formaldehyde, while the photocatalytic performance for toluene oxidation decreases. The overall performance (toluene and formaldehyde degradation) of the system can be optimized with respect to the choice of support for the catalyst (e.g. TiO2 or CeO2), the quantity of Pt used, and the ratio between the catalyst and photocatalyst. In addition, different configurations of the photocatalyst and the catalyst on the textile are studied: under leaching and flow-through gas streams, catalyst and photocatalyst deposition on the same and opposite site of the textile are tested. The performance of the system can be optimized by adapting a configuration where the gas stream goes through the textile, while the deposition side of the catalyst and/or photocatalyst with respect to the gas stream is of minor importance.

Septorhinoplasty by disarticulation: early assessment of a new technique for morphological correction of crooked noses.

OBJECTIVE: This study was aimed to assess the early morphological results of a new septorhinoplasty technique based on disarticulation (SRD) between bony and cartilaginous nose structures. METHODOLOGY: A retrospective, multi-judge, blind comparison of pre- and post-operative photographs displayed on Google documents was designed. A nasal morphology analysis grid based on 10 items was fulfilled independently by 6 judges to assess pre- and post-operatively, two times with a 15 day interval, the severity of each deformity by a score between 0 and 2. The sum of all deformities in a single patient produced the individual global score of nasal deformity, which was set between 0 and 20 for each patient. Pre- and post-operative individual global scores were compared using Student`s t test on paired samples. Percentages of post-operative improvement and deterioration were calculated for each item. RESULTS: Thirty-five SRD were analyzed. Before surgery, 80% of noses were humped and 86% were crooked; three months after surgery, 64% of noses had a rectilinear nasal crest on profile and 57% on facial view. The mean global score of deformities drop- ped from 11.1 before surgery to 5.8 after surgery, an improvement of 47% . Improvement rates of 82% and 74.3% were obtained, respectively, for hump profiles and orbitonasal lines. DISCUSSION: The early morphological results of SRD allow to propose this technique as a possible solution to correct crooked noses with humps.

Pathology of tumours originating in the olfactory cleft.

UNLABELLED: PROBLEMS/OBJECTIVE: This study describes the variety of tumours originating in the olfactory cleft which have been treated with endonasal endoscopic surgery. METHODOLOGY: The study is a retrospective review covering a seven-year period (2004-2010) of the medical records of all patients in whom a tumour originating in the olfactory cleft was excised (72 patients: 63 men and 9 women; age: average of 61 years; range, 19 to 90 years). RESULTS: The most common tumours in the series were adenocarcinoma (43 [60%] patients), inverted papilloma (7 [10%] patients), respiratory epithelial adematoid hamartoma (6 [8%] patients) and olfactory neuroblastoma (5 [7%] patients). CONCLUSIONS: The olfactory cleft can be identified as a new surgical field for endonasal endoscopic surgery. This anatomic region is amenable to endoscopic evaluation and the excision of tumours. Exenteration of the olfactory cleft appears to be a key technique for removing adenocarcinoma and can be extended to exenteration of the olfactory groove in cases with intracranial extension. Partial exenteration of the olfactory cleft would seem to be a suitable way of removing benign tumours like inverted papilloma or respiratory epithelial adematoid hamartoma.

A comparison of fibre counting across three European national proficiency testing schemes.

Proficiency testing (PT) schemes seek to improve and maintain consistency in asbestos fibre counting by circulating mounted samples to laboratories, which return counts for comparison with consensus reference values. This study compares the level of these consensus values in three (Spanish, Belgian and UK) national PT schemes. It also assesses the effect of the imminent change in the European standard rules for counting asbestos fibres, to the new rules from the World Health Organisation (WHO), which will include more fibres. Forty samples from the three schemes were circulated to six laboratories, two in each national scheme. The UK and Spanish laboratories counted using both the ERM and the WHO method. Belgian laboratories already use the WHO method, and they counted only by this method. Densities from counts in this sample exchange served as a common basis against which we compared the national reference values (R). This produced a geometric overall mean ratio of R to exchange mean density of 0.94 for the UK scheme, 1.01 for the Spanish and 0.97 for the Belgian scheme, and thus indicated remarkably similar levels. Nevertheless, non-trivial systematic inter-laboratory differences confirmed the need for regular PT and international inter-laboratory comparisons. Examination of previous data from the national PT schemes and from an international scheme (AFRICA) provided further comparisons for the same laboratories (either comparing the laboratory's data with R values or making direct comparisons between laboratories) that are consistent with those from this special exchange. The change in fibre counting rule (to include fibres apparently touching particles with diameter >3 microm) produced mean increases in reported densities that ranged among samples from 0 to 70% (highest individual estimate 170%); the effect was broadly similar for the three schemes. The laboratories gave mostly similar estimates of percentage increase; however, one laboratory occasionally produced high estimates indicating a possible need for training for using the new method.

Sampling and analysis of carbon in diesel exhaust particulates--an international comparison.

OBJECTIVES: The European Co-ordination on Diesel Soot Exposure (ECDSE) working group organised a laboratory inter-comparison which integrated both the sampling and the analytical determination. The aim was to gain more information on the performance of the methods for the determination of diesel particulate matter at workplaces and on their comparability, and to also confirm that the requirements of the European standard EN 482 are fulfilled for this analytical procedure. METHODS: Sampling was carried out in a diesel aerosol test chamber where participants used their own sampling devices. Overall, ten sampling exercises at two different concentration levels were performed and both personal air sampling systems and stationary samplers were used. The analytical determination was performed according to the laboratory's own standard procedure. RESULTS: There was good agreement between the laboratories for the determination of organic carbon (OC), elemental carbon (EC) and total carbon (TC). Almost all the results when expressed as a coefficient of variation were in the range +/-30% of the overall means. The results also showed that the coefficient of variation for OC was approximately twice the coefficient of variation for EC. This is not too critical, because existing occupational exposure levels (OELs) are based on the measurement of EC. CONCLUSIONS: The inter-comparison showed that existing analytical procedures for the determination of diesel particulate matter at workplaces fulfil the requirements of European standard EN 482. Both personal air samplers and stationary samplers give comparable results. The parameters for the analytical determination are not critical within the range of parameter values presented in this article. Additionally, it may be concluded that the diesel aerosol test chamber used in this exercise is well suited for producing an atmosphere containing a constant and reproducible level of diesel particulate matter.

Further round-robin tests to improve the comparability between laboratories of the measurement of carbon in diesel soot and in environmental samples.

OBJECTIVES: An informal European coordination group organized two round-robin tests on filters collected from environmental, workplace and diluted diesel emissions. Previous inter-laboratory comparisons have shown that experimental samples give reasonably good results in terms of the dispersion around the mean, from all the participating laboratories. However, there were significant differences between the laboratories owing to a narrow distribution of the results within a single laboratory. In order to gain a better understanding of the differences obtained between the laboratories, it was decided to carry out more round-robin tests and to investigate further the possible factors which may influence the results. METHODS: The first round-robin (RRT3) was performed on six different samples (eight replicates) analyzed by ten laboratories. The range of loading was 40 to 138 micrograms cm-2 of total carbon (TC). Laboratories used their own thermal procedure parameters. The second round-robin test (RRT4) was performed on three different diluted diesel emissions (two replicates) samples analyzed by 13 laboratories. The range of loading was 21 to 37 micrograms cm-2 TC. Laboratories analyzed samples using imposed temperatures (500, 650 and 800 degrees C) and imposed duration (12 min). RESULTS: Inter-laboratory coefficients of variation for diluted diesel emission samples were 10% for RRT3 and ranged from 6 to 19% for RRT4. The influence of the desorption temperature was clearly demonstrated and the results tended to show that a desorption temperature of 650 degrees C could be an acceptable compromise. The influence of the organic carbon/elemental carbon (OC/EC) ratio was shown to be insignificant with pure diesel soot samples. CONCLUSIONS: It was expected that a significant improvement would be seen in the inter-laboratory dispersion by the use of a common standardized thermal desorption program, but the objectives of these RRTs were only partly reached. This paper provides new information that will be useful in the elaboration of a standardized procedure for the European Normalisation Centre (CEN TC 137 WG2--General requirements for measuring procedures).

European standardization: guidance on the assessment of occupational exposure to chemical agents. CEN TC 137.

Working group 1 of CEN TC 137 has produced a draft proposal for the assessment of exposure to chemical agents and measurement strategy. A review of the standard is given. The purpose is to give practical guidance to those who have to carry out these assessments. A systematic approach allows the number of measurements to be reduced. The report of the work done allows communication in an efficient way with interested parties: workers, occupational physicians and the labour inspectorate.

Relation between the iodine azide test and the TTCA test for exposure to carbon disulphide.

Exposure to carbon disulphide (CS2) in a viscose plant was measured by personal monitoring and by application of the iodine azide test and quantification of 2-thio-thiazolidine-4-carboxylic-acid (TTCA) in urine samples. A relation was found between the rise in urinary TTCA concentration during the workshift and the exposure index E1. The correlation (r) between the exposure index and the atmospheric concentrations of CS2 in workroom air below 100 mg CS2/m3 was 0.59 (n = 9). The correlation between the increase in TTCA concentrations during the workshift and the atmospheric CS2 concentrations was found to be higher when urine samples at the end of the workshift with creatinine concentrations below 1 mg/ml and above 3 mg/ml were disregarded (from r = 0.61; n = 20 to r = 0.84; n = 14). A high correlation was found (r = 0.86; n = 13) when the end of workshift urine samples were analysed, provided that their creatinine concentrations are not beyond the limits given above.

Exposure data in the viscose industry. Achilles'heel of carbon disulphide epidemiology?

A review of 94 papers including 32 mentioned in the TLV documentation, shows that measurement methodology was poorly described in many studies on exposure in the viscose industry. Stationary and personal monitoring of CS2 exposure in two viscose factories showed considerable variations according to site, time and job titles. Possible biases due to inadequate assessement of exposure in the study of dosis-effect relationship by epidemiologic methods is discussed.

Preliminary evaluation of urinary 2-thio-thiazolidine-4-carboxylic-acid (TTCA) levels as a test for exposure to carbon disulfide.

The exposure to carbon disulfide of workers in charge of different jobs in a Belgian viscose plant was measured by means of personal monitoring of the inhaled air and by quantitative assay of 2-thio-thiazolidine-4-carboxylic acid (TTCA) in urine. It was found that the atmospheric carbon disulfide concentration varied considerably among different jobs, among different individuals doing the same jobs and for the same individuals in the course of the working period. The 2-thio-thiazolidine-4-carboxylic-acid levels increased markedly during the exposure. The correlation between individual personal monitoring results and the increase TTCA levels was found to be statistically significant.