Antimicrobial use and antimicrobial susceptibility in Escherichia coli on small- and medium-scale pig farms in north-eastern Thailand.

BACKGROUND: Intensification of livestock production seen in many low- and middle-income countries is often believed to be associated with increased use of antimicrobials, and may hence contribute to the emergence of antimicrobial resistance. The aim of this study was to map antimicrobial use on small- (n = 25) and medium-scale (n = 27) pig farms in north-eastern Thailand, and to compare antimicrobial susceptibility of commensal Escherichia coli isolated from sows on these farms. METHODS: Information regarding pig husbandry and antimicrobial treatment regimens was obtained by the use of semi-structured questionnaires. Faecal samples were collected from three healthy sows at each farm, and Escherichia coli was cultured and analysed for antimicrobial susceptibility using the broth microdilution method. Multilevel regression models were used to compare antimicrobial susceptibility between isolates from small- and medium-scale farms. RESULTS: All farms included in the study administered antimicrobials to their sows. Small-scale farmers most commonly (64%) decided themselves when to give antimicrobials and the majority (60%) bought the medicines at the local store or pharmacy, whereas farmers on medium-scale farms always discussed antimicrobial treatment with a veterinarian. Medium-scale farms used a greater diversity of antimicrobials than small-scale farms and did also administer antimicrobials in feed to a higher extent. High levels of antimicrobial resistance to several critically important antimicrobials for human medicine (including ciprofloxacin, streptomycin and ampicillin) were found in isolates from both small- and medium-scale farms. Resistance levels were significantly (P < 0.05) higher in isolates from medium-scale farms for several of the antimicrobials tested, as well as the level of multidrug-resistance (P = 0.026). CONCLUSION: The routines regarding access and administration of antimicrobials differed between the small- and medium-scale farms. Although the level of antimicrobial resistance, as well as multidrug-resistance, was higher in isolates from medium-scale farms, it cannot be concluded if this increase is a consequence of a more abundant use of antimicrobials, or a result of differences in administration routines.

Merging Features from Green's Functions and Time Dependent Density Functional Theory: A Route to the Description of Correlated Materials out of Equilibrium?

We propose a description of nonequilibrium systems via a simple protocol that combines exchange-correlation potentials from density functional theory with self-energies of many-body perturbation theory. The approach, aimed to avoid double counting of interactions, is tested against exact results in Hubbard-type systems, with respect to interaction strength, perturbation speed and inhomogeneity, and system dimensionality and size. In many regimes, we find significant improvement over adiabatic time dependent density functional theory or second Born nonequilibrium Green's function approximations. We briefly discuss the reasons for the residual discrepancies, and directions for future work.

Three-dimensional dynamics of a fermionic Mott wedding-cake in clean and disordered optical lattices.

Non-equilibrium quantum phenomena are ubiquitous in nature. Yet, theoretical predictions on the real-time dynamics of many-body quantum systems remain formidably challenging, especially for high dimensions, strong interactions or disordered samples. Here we consider a notable paradigm of strongly correlated Fermi systems, the Mott phase of the Hubbard model, in a setup resembling ultracold-gases experiments. We study the three-dimensional expansion of a cloud into an optical lattice after removing the confining potential. We use time-dependent density-functional theory combined with dynamical mean-field theory, considering interactions below and above the Mott threshold, as well as disorder effects. At strong coupling, we observe multiple timescales in the melting of the Mott wedding-cake structure, as the Mott plateau persist orders of magnitude longer than the band insulating core. We also show that disorder destabilises the Mott plateau and that, compared to a clean setup, localisation can decrease, creating an interesting dynamic crossover during the expansion.

Analysis of toxic effluents released from PVC carpet under different fire conditions.

A large number of investigations have been reported on minimising the PAH and PCDD/F yields during controlled combustion, such as incineration. This study is an attempt to quantify acute and chronic toxicants including PAH and PCDD/F in conditions relating to unwanted fires. This paper investigates distribution patterns of fire effluents between gas and aerosol phase, and the different particle size-ranges produced under different fire conditions. PVC carpet was selected as the fuel as a precursor for both PAH and PCDD/F. In order to generate fire effluents under controlled fire conditions, the steady-state tube furnace, was chosen as the physical fire model. Fire scenarios included oxidative pyrolysis, well-ventilated and under-ventilated fires. Fire effluent measurements included: carbon monoxide, carbon dioxide, hydrogen chloride, polycyclic aromatic hydrocarbons, chlorinated dibenzo-dioxins and furans and soot. The distribution patterns between gas and particle phase, and the size-ranges of the particles produced in these fires together with their chemical composition is also reported. Significant quantities of respirable submicron particles were detected, together with a range of PAHs. Lower levels of halogenated dioxins were detected in the fire residue compared with those found in other studies. Nevertheless, the findings do have implications for the health and safety of fire and rescue personnel, fire investigators, and other individuals exposed to the residue from unwanted fires.

Probabilistic network modelling of the impact of penicillin consumption on spread of pneumococci.

The worldwide increase of resistant S. pneumoniae is a growing clinical problem. In several countries, a more restrictive use of penicillin has been promoted in hope of slowing the rates of resistant pneumococci. However, the consequences of such an action on pneumococcal population dynamics are not fully understood. Thus, a network model was constructed to assess the impacts of penicillin consumption and between-strain competition on the spread of penicillin non-susceptible pneumococci. Model simulations suggest that the age distribution for carriage of penicillin non-susceptible pneumococci, in contrast to susceptible pneumococci, is affected by penicillin consumption. Furthermore, it appears extremely difficult to reduce the incidence of penicillin non-susceptible pneumococci by simply controlling penicillin consumption, assuming that reduced penicillin susceptibility does not confer a fitness cost for the organism. A more judicious use of penicillin together with control measures are in that case required to manage penicillin resistance in pneumococci.

Modelling of different measures for improving removal in a stormwater pond.

The effect of retrofitting an existing pond on removal efficiency and hydraulic performance was modelled using the commercial software Mike21 and compartmental modelling. The Mike21 model had previously been calibrated on the studied pond. Installation of baffles, the addition of culverts under a causeway and removal of an existing island were all studied as possible improvement measures in the pond. The subsequent effect on hydraulic performance and removal of suspended solids was then evaluated. Copper, cadmium, BOD, nitrogen and phosphorus removal were also investigated for that specific improvement measure showing the best results. Outcomes of this study reveal that all measures increase the removal efficiency of suspended solids. The hydraulic efficiency is improved for all cases, except for the case where the island is removed. Compartmental modelling was also used to evaluate hydraulic performance and facilitated a better understanding of the way each of the different measures affected the flow pattern and performance. It was concluded that the installation of baffles is the best of the studied measures resulting in a reduction in the annual load on the receiving lake by approximately 8,000 kg of suspended solids (25% reduction of the annual load), 2 kg of copper (10% reduction of the annual load) and 600 kg of BOD (10% reduction of the annual load).

Medical decision-support systems and the concept of context.

Medical decision-support systems are of necessity multi-contextual in nature. There are always at least two contexts involved in the use of such systems: the expert knowledge-provider context and the end-user context. To show this, we present examples of context-dependent aspects significant to the use of decision-support systems. The existence of discrepancies between the contexts threatens to disrupt the rationale for using decision-support systems: for the system to transfer knowledge from the expert to the end-user. Both theoretical and empirical studies show that such discrepancies exist and that they may be detrimental to the use of decision-support systems. Systems must thus give support in interpreting the output produced by the system in the context of the end-user.

Significance of house painters' work techniques on shoulder muscle strain during overhead work.

House painters represent a group of construction workers with a high frequency of neck and shoulder complaints and concomitant high risks for early retirements. Shoulder tendinitis, especially supraspinatus tendinitis, occurs frequently among house painters. The tasks of sanding and painting of ceilings with extension handles are particularly strenuous for these body regions. The purpose of this study was to identify work techniques that would be less strenuous to the arms and shoulders during sanding work. A biomechanical model was applied to quantify the shoulder loads during sanding and to determine the likely muscle force distribution. The necessary input data were measured experimentally for the model by means of a load cell and strain gauges on an extension handle, a Kistler force plate, and a MacReflex motion analysis system. Forty experienced male painters participated in the study. Three different work techniques were identified: the normal technique, the reversed grip and the pushing technique. The pushing technique was characterized by shorter stroke length and lower speed of the grinding block than the other techniques. The painters among the group of subjects who used the pushing technique were found to report fewer shoulder disorders during sanding than the others. The most common shoulder tendinitis is the supraspinatus tendinitis, also among house painters, and using the Pushing technique could possibly prevent from this disorder. However, further research in larger groups of house painters is needed to be able to recommend this technique for a wider use.

A design and prototype for a decision-support system in the field of urinary tract infections--application of OpenGALEN techniques for indexing medical information.

Differences in expert and end-user contexts may be detrimental to the use of decision-support systems. A way to attend to this problem is to triangulate decision-support methods and information sources such as in the case of the expertext system model. To organize the information contained in the system, a common domain model is suggested as a instrument for annotating information. In this paper, a design and a prototype for a decision-support system in the field of urinary tract infections using techniques and methods developed in the GALEN projects is presented.

Building a concept system to structure the contents of a decision support system--a grounded theory study of concepts in the knowledge domain of urinary tract infection.

In this study we present a concept system for the knowledge domain of urinary tract infections. The system was constructed using grounded theory methods, sampling from Swedish reference texts and patient records from consultations for urinary tract infections. The concept system is intended for use as an aid in the construction of a decision support system (DSS) for urinary tract infections, and as a search module in the mentioned DSS. In total 561 concepts were categorized in four major, and 58 subordinate categories. Relationships between the more important categories were developed, and the frequency of use of the most common concepts is presented. Using the presented categorical structure as domain model a prototype DSS for dipslide urine cultures has been developed.

Determination of isocyanic acid in air.

A method is presented for the determination of isocyanic acid (ICA), HNCO, in air samples as a di-n-butylamine (DBA) derivative. The method is based on sampling in midget impinger flasks containing 10 ml of 0.01 mol l-1 DBA in toluene. Quantification was made using liquid chromatography (LC) and electrospray mass spectrometry (MS) monitoring positive ions. The instrumental detection limit for the LC-MS was 10 fmol of ICA-DBA. ICA was generated by thermal decomposition of urea. A standard solution containing the DBA derivatives of ICA was prepared by collecting the emitted ICA in an impinger flask containing DBA. ICA in the reference solution was characterised by LC and time-of-flight (TOF) MS and quantified by LC chemiluminescent nitrogen detection (LC-CLND). The instrumental detection limit for the LC-CLND was 1 ng of nitrogen. ICA was emitted during thermal degradation of PFU resins and polyurethane (PUR) lacquers, from car metal sheets. ICA was the most dominant isocyanate and in PUR coating up to 8% of the total weight was emitted as ICA and for PFU resins up to 14% was emitted as ICA. When air samples were collected in an iron foundry during casting in sand moulds with furan resins, concentrations of ICA in the range 50-700 micrograms m-3 were found in the working atmosphere.

A study of the usage of a decision-support system for infective endocarditis.

The objective of this study was to examine a design for a World Wide Web-based decision-support system in use by clinically active physicians. A prototype implementation of the design concerned management of infective endocarditis patient cases. The design was based on an integration of hypertext and rule-based knowledge. In the study sessions, physicians in the field of internal medicine worked on managing authentic patient cases in a laboratory setting. Data was collected from interviews with the physicians using video recordings and stimulated recall technique. The qualitative data was analysed according to the constant comparative method in order to develop a model of the physicians' usage of the system. The resulting model describes perceived contributions and criteria for usefulness of the system. The ways the physicians used the system showed that it was able to provide patient-specific support for confirming clinical decisions, for higher-level patient management, and for preparing for and initiating expert consultations. Users also stated that new medical knowledge could be gained as a side effect of using the system.

Airborne thermal degradation products of polyurethene coatings in car repair shops.

A methodology for workplace air monitoring of aromatic and aliphatic, mono- and polyisocyanates by derivatisation with di-n-butylamine (DBA) is presented. Air sampling was performed using midget impinger flasks containing 10 ml of 0.01 mol l(-1) DBA in toluene and a glass-fibre filter in series after the impinger flask, thereby providing the possibility of collecting and derivatising isocyanates in both the gas and particle phases. Quantification was made by LC-MS, monitoring the molecular ions [MH]+. Air samples taken with this method in car repair shops showed that many different isocyanates are formed during thermal decomposition of polyurethane (PUR) coatings. In addition to isocyanates such as hexamethylene (HDI), isophorone (IPDI), toluene (TDI) and methylenediphenyl diisocyanate (MDI), monoisocyanates such as methyl (MIC), ethyl (EIC), propyl (PIC), butyl (BIC) and phenyl isocyanate (PhI) were found. In many air samples the aliphatic monoisocyanates dominated. During cutting and welding operations, the highest levels of isocyanates were observed. In a single air sample from a welding operation in a car repair shop, the highest concentrations found were: MIC, 290; EIC, 60; PIC, 20; BIC, 9; PhI, 27; HDI, 105; IPDI, 39; MDI, 4; and 2,4-TDI and 2,6-TDI 140 microg m(-3). Monitoring the particle size distribution and concentration during grinding, welding and cutting operations showed that ultrafine particles (< 0.1 microm) were formed at high concentrations. Isocyanates with low volatility were mainly found in the particle phase, but isocyanates with a relatively high volatility such as TDI, were found in both the particle and gas phases.

Segmental movements of the spine during treadmill walking with normal speed.

OBJECTIVE: The aim of the present work is to investigate the segmental movement patterns of the spine during normal treadmill gait. DESIGN: The spine movement during treadmill gait of ten healthy subjects (five men and five women) has been investigated using an optoelectronic measuring system. METHODS: The spine was divided into seven segments, from C(7) to S(2). The subjects walked with their normal speed. All data were normalized to per cent of the gait cycle. The normal patterns of the spine segment movements were found in the sagittal and the frontal planes. RESULTS: The behaviour of the spine can be described as the motion of a stiff element with superimposed small, inter-segmental movements. These small inter-segmental movements were found both in the sagittal and the frontal planes. CONCLUSIONS: The small inter-segmental movements could play an important role in the reduction of the energy consumption during gait and in maintenance of the equilibrium. RELEVANCE: Any disability affecting the spine should result in changing spine movement pattern during gait, thus changing the overall gait pattern. Therefore, treatment and rehabilitation should not discard the influence of the spine malfunctioning, regardless of its nature.

Validation of a diffusive sampler for NO2.

A diffusive sampler for NO2, Willems badge, was validated in laboratory experiments and field tests. The collecting reagent for NO2 in the sampler is triethanolamine, and the analysis is based on a modified colorimetric method, the Saltzman method. The analysis was performed by a flow injection analysis (FIA) technique. The sampling rate for the sampler was determined to be 40.0 ml min-1. There was no effect of NO2 concentration or relative humidity on sampling rate, and the influence of sampling time was found to be small. The detection limit was 4 micrograms m-3 for a 24 h sample. The capacity is high enough to allow sampling of 150 micrograms m-3 for 7 days, which is twice the recommended Swedish short-term (24 h) guideline value as a 98-percentile over 6 months. In field tests, the sampler performed well, even at wind speeds higher than 2 m s-1, and at low temperatures. The overall uncertainty of the method was 24%. The sensitivity and capacity of the method also make it suitable for personal sampling for 2-8 h in working environments.

Concepts, contexts and expert systems.

This paper describes problems identified in our attempts to develop an expert system for management of urinary tract infections. We found three aspects which we believe are important to consider when developing such systems. The objective of our future work will be to evaluate the impact of these problems on expert system development and usage.

Determination of complex mixtures of airborne isocyanates and amines. Part 5. Determination of low molecular weight aliphatic isocyanates as dibutylamine derivatives.

A method is presented for the determination of low molecular weight aliphatic isocyanates, methyl isocyanate (MIC), ethyl isocyanate (EIC), propyl isocyanate (PIC) and butyl isocyanate (BIC), as their dibutylamine (DBA) derivatives. The method is based on sampling in midget impinger flasks containing 10 ml of 0.01 mol l-1 DBA in toluene (as in Parts 1-4 in this series). The samples are analysed using liquid chromatography-electrospray mass spectrometry (LC-ESP-MS) or gas chromatography-mass spectrometry using chemical ionisation with ammonia, monitoring positive ions (GC-PCI). Quantification was effected by monitoring the molecular ions MH+. Aliquots of 10 ml of toluene solutions containing 0.01 mol l-1 DBA were spiked with 0.03-0.85 microgram of MIC-, EIC-, PIC- and BIC-DBA. The correlation coefficients for LC-ESP-MS were in the range 0.9952-0.9999 (n = 14). The repeatability (RSD) was in the range 0.37-1.2% (0.12-0.34 microgram ml-1, n = 10). The instrumental detection limit for MIC was about 15 micrograms l-1, which corresponds to about 0.5 microgram m-3 in a 15 l air sample. The correlation coefficients for GC-PCI were in the range 0.9913-0.9990. The repeatability (RSD) was in the range 1.1-4.9% (0.12-0.34 microgram ml-1, n = 10). The instrumental detection limit for MIC was about 0.2 microgram l-1, which corresponds to about 0.05 microgram m-3 in a 15 l air sample. Using electron ionisation, the instrumental detection limit for MIC was about 10 micrograms l-1. No derivatisation reaction losses were seen when the derivatization reaction between PIC and DBA took place in the presence of morpholine, propylamine, ethanol, phenol and water. When mineral wool with a phenol-formaldehyde-urea resin was thermally degraded, 0.1% m/m of MIC was released. In air samples taken on top of a new electric oven insulated with mineral wool, MIC was found in the range 0.1-3 mg m-3. No MIC in air was found from a pre-heated oven.

Design and application of a terminology management system.

A Swedish data model for handling terminology, Spriterm, is presented in this paper. A prototype terminology management system, using the Spriterm data model in also described. This prototype is implemented is Microsoft ACCESS. Furthermore, two other applications using this prototype as a base are introduced. One World Wide Web based application, and a data dictionary.

Extended telemedical consultation using Arden Syntax based decision support, hypertext and WWW technique.

There is an obvious need for geographic distribution of expert knowledge among several health care units without increasing the cost of on-site expertise in locations where health care is provided. This paper describes the design of a knowledge-based decision-support system for extended consultation in clinical medicine. The system is based on Arden Syntax for Medical Logic Modules and hypertext using World Wide Web technology. It provides advice and explanations regarding the given advice. The explanations are presented in a hypertext format allowing the user to browse related information and to verify the relevance of the given advice. The system is intended to be used in a closed local network. With special precautions regarding issues of safety and patient security, the system can be used over wider areas such as in rural medicine. A prototype has been developed in the field of clinical microbiology and infectious diseases regarding infective endocarditis.