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Background: Intrahospital transport is associated with a high rate of complications. Investigations of this problem using neuromonitoring remain scarce.Methods: This is a monocentric, prospective observational study. Patients with severe brain diseases and intracranial pressure (ICP) monitoring were included. Continuous monitoring of ICP, cerebral perfusion pressure (CPP), oxygen saturation (SpO2), heart rate, and mean arterial pressure was measured during seven different periods of intrahospital transport (baseline for 30 min, I = preparation, II = transport I, III = CT scan, IV = transport II, V = postprocessing, and follow-up for another 30 min). All complications were documented.Results: Between July 2013 and December 2013, a total number of 56 intrahospital transports of 43 patients were performed from ICU to CT. Data recording was incomplete in six cases. Fifty transports have been taken into account for statistical analysis. Forty-two percent were emergency transports. Mean duration of the procedure was 17' (preparation), 6' (transport I), 9' (CT scan), 6' (transport II), and 15' (postprocessing), respectively. Mean ICP at baseline was 8.53 mmHg. Comparing all periods of intrahospital transport and the follow-up period to the baseline showed a significant increase of ICP only during CT scan (15.83 mmHg, p < 0.01), not during the transport to and from the radiology department. An overall complication rate of 36 % (n = 18) was observed. In 26 % (n = 13), additional ICP therapy was necessary due to an elevation of ICP above 20 mmHg.Conclusion: There is a considerable rate of complications during intrahospital transport of critically ill patients with severe brain diseases, with a significant increase of ICP during transport and CT scan. In one-fifth of all patients, additional therapy was necessary. From our point of view, transport of critically ill patients should only be performed by trained staff and under monitoring of ICP and CPP. [ABSTRACT FROM AUTHOR]

Abstract: The oxidation capacity of the highly polluted urban area of Santiago de Chile has been evaluated during a winter measurement campaign from May 25 to June 07, 2005, with the results compared and contrasted with those previously evaluated during a summer campaign from March 8 to 20, 2005. The OH radical budget was evaluated in both campaigns employing a simple quasi-photostationary state model (PSS) constrained with simultaneous measurements of HONO, HCHO, O3, NO, NO2, j(O1D), j(NO2), 13 alkenes and meteorological parameters. In addition, a zero dimensional photochemical box model based on the Master Chemical Mechanism (MCMv3.1) has been used for the analysis of the radical budgets and concentrations of OH, HO2 and RO2. Besides the above parameters, the MCM model has been constrained by the measured CO and other volatile organic compounds (VOCs) including alkanes and aromatics. Total production and destruction rates of OH and HO2 in winter are about two times lower than that during summer. Simulated OH levels by both PSS and MCM models are similar during the daytime for both winter and summer indicating that the primary OH sources and sinks included in the simple PSS model are predominant. On a 24 h basis, HONO photolysis was shown to be the most important primary OH radical source comprising 81% and 52% of the OH initiation rate during winter and summer, respectively followed by alkene ozonolysis (12.5% and 29%), photolysis of HCHO (6.1% and 15%), and photolysis of O3 (<1% and 4%), respectively. During both winter and summer, there was a balance between the OH secondary production (HO2 + NO) and destruction (OH + VOCs) showing that initiation sources of RO2 and HO2 are no net OH initiation sources. This result was found to be fulfilled also for all other studies investigated. Seasonal impacts on the radical budgets are also discussed. [Copyright &y& Elsevier]

Abstract: The city of Santiago, Chile experiences frequent high pollution episodes and as a consequence very high ozone concentrations, which are associated with health problems including increasing daily mortality and hospital admissions for respiratory illnesses. The development of ozone abatement strategies requires the determination of the potential of each pollutant to produce ozone, taking into account known mechanisms and chemical kinetics in addition to ambient atmospheric conditions. In this study, the photochemical formation of ozone during a summer campaign carried out from March 8–20, 2005 has been investigated using an urban photochemical box model based on the Master Chemical Mechanism (MCMv3.1). The MCM box model has been constrained with 10 min averages of simultaneous measurements of HONO, HCHO, CO, NO, j(O1D), j(NO2), 31 volatile organic compounds (VOCs) and meteorological parameters. The O3–NOx–VOC sensitivities have been determined by simulating ozone formation at different VOC and NOx concentrations. Ozone sensitivity analyses showed that photochemical ozone formation is VOC-limited under average summertime conditions in Santiago. The results of the model simulations have been compared with a set of potential empirical indicator relationships including H2O2/HNO3, HCHO/NOy and O3/NOz. The ozone forming potential of each measured VOC has been determined using the MCM box model. The impacts of the above study on possible summertime ozone control strategies in Santiago are discussed. [Copyright &y& Elsevier]

Abstract: Recent studies have demonstrated that nitrous acid (HONO) is a source of hydroxyl radicals (OH) in the boundary layer not only early in the morning but also throughout the day. Despite its importance, all known instruments to detect HONO in the atmosphere suffer either from the great experimental effort necessary or from the possibility of significant interferences. In addition, only a few instruments are sensitive enough to detect low HONO concentrations during daytime. Accordingly, validated and sensitive measurements of nitrous acid are of paramount importance to describe the oxidation capacity of the atmosphere. Up to now, in intercomparisons of these chemical detectors with the well accepted DOAS technique significantly higher concentrations have been detected during the day with the chemical detectors, the discrepancy being attributed to interferences. In the present study, a recently developed HONO instrument (LOPAP) was validated against the DOAS technique, both in the field and in a large smog chamber under various conditions. Since sampling artefacts were minimised and interferences were measured and corrected for by the LOPAP instrument excellent agreement was obtained between these techniques during daytime as well as night-time. It is demonstrated that chemical instruments, which do not measure and do not correct interferences may significantly overestimate daytime concentrations of HONO caused by unknown interferences, which are particularly important during daytime, when HONO concentrations are low. For the DOAS technique, the possibility of HONO impurities in the NO2 reference spectra used for the spectral analysis needs to be treated actively in the evaluation process, to avoid a potential negative interference at low HONO/NO2 ratios. A simple procedure is presented that eliminates this possible error source in DOAS measurements of HONO in the atmosphere. [Copyright &y& Elsevier]

Background and purpose Some authors have suggested a rise of intracranial pressure ( ICP) during apnoea testing and the possibility of harm to patients. Data, however, have yet to be obtained. Methods Between October 2012 and May 2014 an observational study was performed on patients who received ICP measurements and who underwent brain death diagnosis. ICP, cerebral perfusion pressure ( CPP), mean arterial blood pressure ( MAP) and heart rate were recorded continuously from 15 min before the start of brain death diagnosis (baseline), during clinical examination including apnoea testing, until 15 min after this procedure. Results A total of 16 clinical examinations for brain death including apnoea testing were performed on 13 patients. All patients had primary brain lesions. Mean ICP and mean CPP during the examination were 95 ± 27.7 mmHg and 13.5 ± 20.7 mmHg, respectively. ICP and MAP showed a strong and statistically significant correlation, with Pearson's correlation coefficients of more than +0.6 or less than -0.6 in 13 of the 15 examinations. Conclusion Mean ICP even before brain death determination is increased excessively. Changes of ICP during apnoea show a clear correlation to the changes of MAP. Furthermore, CPP during the condition of brain death may not equal zero but may be positive thereby indicating some minor net influx of blood into the brain in some patients. [ABSTRACT FROM AUTHOR]

Small scale bed flow photoreactor experiments were performed to assess the photocatalytic performance of cement-based TiO 2 -containing materials for NO x reduction through the determination of kinetic parameters under variation of the experimental conditions (relative humidity, flow rate, mixing ratio and light intensity) and monitoring of potential reaction products in the gas phase and the aqueous extract of the surface. The results clearly demonstrated the general potential of the tested material to photocatalytically remediate gas phase NO x by conversion into nitrite and nitrate as identified reaction products at the surface. The measured uptake coefficients for NO and NO 2 under atmospheric relevant conditions were in the range of 5 × 10 −5 with a corresponding surface deposition velocity of about 0.5 cm s −1 . However, it became also clear that the photocatalytic activity is in part significantly dependent on the experimental conditions. The relative humidity and the mixing ratio of the air pollutant were identified as the most important parameters. In addition, under certain conditions, a renoxification process can occur. The comprehensive results of the present study are discussed in detail to develop recommendations for a possible future application of this technique to improve urban air quality. [ABSTRACT FROM AUTHOR]

In several previous studies emission of ozone (O 3 ) during fireworks has been reported, which was attributed to either photolysis of molecular oxygen (O 2 ) or nitrogen dioxide (NO 2 ) by short/near UV radiation emitted during the high-temperature combustion of fireworks. In contrast, in the present study no O 3 formation was observed using a selective O 3 -LOPAP instrument during the combustion of pyrotechnical material in the laboratory, while a standard O 3 monitor using UV absorption showed extremely high O 3 signals. The artificial O 3 response of the standard O 3 monitor was caused by known interferences associated with high levels of co-emitted VOCs and could also be confirmed in field measurements during New Year's Eve in the city of Wuppertal, Germany. The present results help to explain unreasonably high ozone levels documented during ambient fireworks, which are in contradiction to the fast titration of O 3 by nitrogen monoxide (NO) in the night-time atmosphere. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "The Clinical Determination of Brain Death: Practice Limitations" by M. J. Rady and colleagues in the 2015 issue.

A response from the author of the article "Intracranial pressure and cerebral perfusion pressure during apnoea testing for the diagnosis of brain death-an observational study" is presented.

Background and purpose Theoretical considerations and the results of animal studies indicate that manual lymphatic drainage ( MLD) might have an impact on intracranial pressure ( ICP). There is a lack of clinically qualitative investigations on patients with severe cerebral diseases. Methods Between April 2013 and January 2015 a prospective observational study was performed on patients who were undergoing intracranial pressure measurement and treatment with MLD. ICP, cerebral perfusion pressure, mean arterial pressure ( MAP), heart rate and oxygen saturation were recorded continuously 15 min before the procedure, during MLD (22 min) and for 15 min after the procedure. For analysis the data treatment units were divided into two groups: patients with a mean baseline ICP <15 mmHg (group 1) and patients with a mean ICP ≥15 mmHg before MLD (group 2). Results A total of 133 treatment units (61 patients) were analysed (group 1 n = 99; group 2 n = 34). The mean baseline ICP was 10.4 mmHg overall, and 8.3 mmHg and 18.6 mmHg respectively in group 1 and group 2; ICP significantly decreased during therapy with MLD and this persisted during the follow-up period in group 2. MAP did not show any significant differences between the different periods. Conclusions Our data showed a significant reduction of ICP during therapy with craniocervical MLD in patients with severe cerebral diseases. [ABSTRACT FROM AUTHOR]

Hydroxyl radicals (OH) are known to control the oxidative capacity of the atmosphere but their influence on reactivity within indoor environments is believed to be of little importance. Atmospheric direct sources of OH include the photolysis of ozone and nitrous acid (HONO) and the ozonolysis of alkenes. It has been argued that the ultraviolet light fraction of the solar spectrum is largely attenuated within indoor environments, thus, limiting the extent of photolytic OH sources. Conversely, the ozonolysis of alkenes has been suggested as the main pathway of OH formation within indoor settings. According to this hypothesis the indoor OH radical concentrations span in the range of only 104 to 105 cm-3. However, recent direct OH radical measurements within a school classroom yielded OH radical peak values at moderate light intensity measured at evenings of 1.8 × 106 cm-3 that were attributed to the photolysis of HONO. In this work, we report results from chamber experiments irradiated with varying light intensities in order to mimic realistic indoor lighting conditions. The exhaust of a burning candle was introduced in the chamber as a typical indoor source causing a sharp peak of HONO, but also of nitrogen oxides (NOx). The photolysis of HONO yields peak OH concentration values, that for the range of indoors lightning conditions were estimated in the range 5.7 ×. 106 to 1.6 × 107 cm-3. Excellent agreement exists between OH levels determined by a chemical clock and those calculated by a simple PSS model. These findings suggest that significant OH reactivity takes place at our dwellings and the consequences of this reactivity--that is, formation of secondary oxidants--ought to be studied hereafter. [ABSTRACT FROM AUTHOR]

Within the framework of the European Life+-funded project PhotoPAQ (Demonstration of Photocatalytic remediation Processes on Air Quality) , which was aimed at demonstrating the effectiveness of photocatalytic coating materials on a realistic scale, a photocatalytic de-polluting field site was set up in the Leopold II tunnel in Brussels, Belgium. For that purpose, photocatalytic cementitious materials were applied on the side walls and ceiling of selected test sections inside a one-way tunnel tube. This article presents the configuration of the test sections used and the preparation and implementation of the measuring campaigns inside the Leopold II tunnel. While emphasizing on how to implement measuring campaigns under such conditions, difficulties encountered during these extensive field campaigns are presented and discussed. This included the severe de-activation observed for the investigated material under the polluted tunnel conditions, which was revealed by additional laboratory experiments on photocatalytic samples that were exposed to tunnel air. Finally, recommendations for future applications of photocatalytic building materials inside tunnels are given. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, problems of different methods used for quantifying the air remediation activity of photo-catalytic active surfaces are described. It is demonstrated that in bed photo-reactors (e.g. ISO), transport limitations can lead to underestimation of the activity, if fast heterogeneous reactions are investigated. In contrast, in stirred tank photo-reactors (e.g. UNI), complex secondary chemistry may lead to an overestimation of the photo-catalytic remediation of NO x , if NO2 is also present. In addition, the quantities, used for ranking the photo-catalytic air remediation activity in the different methods are not independent of the applied experimental conditions, and thus, make any intercomparison between the different methods or the extrapolation to atmospheric conditions very difficult. Furthermore, unrealistic high NO x levels are used, for which the chemical kinetics may already be affected by surface saturation problems. Finally, it is shown that the use of only nitrogen monoxide (NO) will not enable users to judge about the quality and effectiveness of a photo-catalytic surface for improving air quality, since surfaces which are active toward NO may be completely non-reactive toward other important atmospheric pollutants. A modified method for quantifying the air remediation activity of photo-catalytic surfaces is proposed here to overcome these problems. [Copyright &y& Elsevier]

Abstract: A simple O3-LOPAP (Long Path Absorption Photometer) instrument for the selective detection of O3 in the atmosphere is presented, which is mainly intended to be used as an extension of a recently developed NO2-LOPAP. O3 is sampled in a stripping coil by a selective chemical reaction with the highly absorbing Indigo dye. The reduction of the optical absorption of the dye is detected in a liquid core waveguide. The instrument has a detection limit of 0.4 ppbv, an accuracy of 10%, a precision of 2% for 6 min time resolution and allows the absolute quantification of O3 according to Lambert–Beer''s law. Interferences towards nitrogen oxides (NO and NO2), N2O5, H2O2 and several VOCs were quantified in the laboratory and found to be negligible for atmospheric conditions. The new instrument was successfully validated against a commercial UV-absorption instrument during an urban field campaign and against the FTIR technique in a smog chamber under complex photosmog conditions. For the UV-absorption instrument significant positive interferences towards aromatic species were observed in the smog chamber. [Copyright &y& Elsevier]

The article offers information on the measurement of trophospheric ozone (O3), nitric oxide (NO), and nitrogen dioxide (NO2) fluxes and its interaction over a bare soil through aerodynamic gradient method. It adds the use of eddy-covariance and automatic chambers for ozone and NO fluxes. It states that chemical interactions of the gasses resulted only to small ozone flux divergence.

The article presents a study which compares the efficiency of different techniques using various instruments in measuring interferences of commercial nitrogen dioxide (NO2) in the urban atmosphere and in a smog chamber. Chemiluminescence instruments with molybdenum or photolytic converters, Luminol based instrument and a proposed NO 2 Long Path Absorption Photometer (LOPAP) were compared with spectroscopic techniques. The methods and results of the study are discussed.

The article presents a study on the development of a compact and simple instrument, Long Path Absorption Photometer (LOPAP), to detect nitrous oxide in the atmosphere. The study states that significant interferences against nitrous acid (HONO) and oxide are suppressed using a HONO/oxide scrubber. The study states that LOPAP allows absolute calibration that can be quickly performed with liquid nitrite standards, and has been validated against chemiluminescence technique.

The article presents a study which measures nitric oxide (NO), tropospheric ozone (O3), and nitrogen dioxide (NO2) fluxes and chemical interactions over an agricultural field. The study assessed NO, O3, and NO2 using the aerodynamic gradient method and vertical mixing ratio profile measurements. Results show that uncertainties of the friction velocity have caused flux uncertainties while O3 are accounted for about 10% on average.

The article presents a study which compares the performances of different commercial nitrogen dioxide (NO2) instruments and a NO2-LOPAP in the urban atmosphere and in a smog chamber in Santiago de Chile. A field experiment was conducted wherein chemiluminescence instruments with molybdenum or photolytic converters were compared to NO2-LOPAP with spectroscopic techniques to detect interferences. Results show strong interferences and agreements in all instruments.

The article focuses on the development of a Long Path Absorption Photometer (LOPAP) instrument for the detection of NO2 in the atmosphere. The instrument is considered more sensitive than known instruments as it has an accuracy of 10 percent and a precision of 0.5 percent for three minutes time resolution. It is also deemed easier to apply than other methods. Its use is validated by intercomparison with chemiluminescence instrument with photolytic NO2 converter.

Abstract: In the present study, photocatalytic reactions of nitrogen oxides (NOx = NO + NO2) were studied on commercial TiO2 doped facade paints in a flow tube photoreactor under simulated atmospheric conditions. Fast photocatalytic conversion of NO and NO2 was observed only for the photocatalytic paints and not for non-catalytic reference paints. Nitrous acid (HONO) was formed in the dark on all paints studied, however, it efficiently decomposes under irradiation only on the photocatalytic samples. Thus, it is concluded that photocatalytic paint surfaces do not represent a daytime source of HONO, in contrast to other recent studies on pure TiO2 surfaces. As main final product, the formation of adsorbed nitric acid/nitrate anion (HNO3/NO3 −) was observed with near to unity yield. In addition, traces of H2O2 were observed in the gas phase only in the presence of O2. Formation of the greenhouse gas nitrous oxide (N2O) could be excluded. The uptake kinetics of NO, NO2 and HONO was very fast under atmospheric conditions (e.g. γ(NO + TiO2) > 10−5). Thus, the uptake on urban surfaces (painted houses, etc.) will be limited by transport. For a hypothetically painted street canyon, an average reduction of nitrogen oxide levels of ca. 5% is estimated. Since the harmful HNO3/NO3 − is formed on the surface of the photoactive paints, whereas it is formed in the gas phase in the atmosphere, the use of photocatalytic paints may also help to reduce acid deposition, e.g. on plants, or nitric acid related health issues. [Copyright &y& Elsevier]