Volatile aldehydes in libraries and archives

Volatile aldehydes are produced during degradation of paper-based materials. This may result in their accumulation in archival and library repositories. However, no systematic study has been performed so far. In the frame of this study, passive sampling was carried out at ten locations in four libraries and archives. Despite the very variable sampling locations, no major differences were found, although air-filtered repositories were found to have lower concentrations while a non-ventilated newspaper repository exhibited the highest concentrations of volatile aldehydes (formaldehyde, acetaldehyde, furfural and hexanal). Five employees in one institution were also provided with personal passive samplers to investigate employees’ exposure to volatile aldehydes. All values were lower than the presently valid exposure limits. The concentration of volatile aldehydes, acetic acid, and volatile organic compounds (VOCs) in general was also compared with that of outdoor-generated pollutants. It was evident that inside the repository and particularly inside archival boxes, the concentration of VOCs and acetic acid was much higher than the concentration of outdoor-generated pollutants, which are otherwise more routinely studied in connection with heritage materials. This indicates that further work on the pro-degradative effect of VOCs on heritage materials is necessary and that monitoring of VOCs in heritage institutions should become more widespread

Computational studies of history-dependence in nematic liquid crystals in random environments

Glassy liquid crystalline systems are expected to show significant history-dependent effects. Two model glassy systems are the RAN and SSS (sprinkled silica spin) lattice models. The RAN model is a Lebwohl-Lasher lattice model with locally coupled nematic spins, together with uncorrelated random anisotropy fields at each site, while the SSS model has a finite concentration of impurity spins frozen in random directions. Here Brownian simulation is used to study the effect of different sample histories in the low temperature regime in a three-dimensional (d=3) model intermediate between SSS and RAN, in which a finite concentration p<pc (pc the percolation threshold) of frozen spins interacts with neighboring nematic spins with coupling W. Simulations were performed at temperature T?TNI/2 (TNI the bulk nematic-isotropic transition temperature) for temperature-quenched and field-quenched histories (TQH and FQH, respectively), as well as for temperature-annealed histories (AH). The first two of these limits represent extreme histories encountered in typical experimental studies. Using long-time averages for equilibrated systems, we calculate orientational order parameters and two-point correlation functions. Finite-size scaling was used to determine the range of the orientational ordering, as a function of coupling strength W,p and sample history. Sample history plays a significant role; for given concentration p, as disorder strength W is increased, TQH systems sustain quasi-long-range order (QLRO) and short-range order (SRO). The data are also consistent with a long-range order (LRO) phase at very low disorder strength. By contrast, for FQH and p?0.1, only LRO and QLRO occur within the range of parameters investigated. The crossover between regimes depends on history, but in general, the FQH phase is more ordered than the AH phase, which is more ordered than the TQH phase. However, at temperatures close to the isotropic-nematic phase transition of pure samples we observe SRO for p=0.1 even for FQH. We detect also in the QLRO phase a domain-type structural pattern, consistent with ideas introduced by Giamarchi and Doussal [Phys. Rev. B 52, 1242 (1995)] on superconducting flux lattices. In the weak-disorder limit the orientational correlation length obeys the Larkin-Imry-Ma scaling ??D?2/(4?d)

REDUCING OF STRESS IN THE HIP JOINT ARTICULAR SURFACE IN SKIING

INTRODUCTION - It was recently shown that too high contact stress in the articular surface of the hip joint can accelerate the arthrosis development in the hip joint ( Hadley et al., 1990). Increased contact stress in the hip joint articular surface can result from too small hip joint articular surface andlor from too high resultant hip joint force. Since the resultant hip joint force. Since the resultant hip -joint force is permanently increased during sport activities it is understandable that the incidence of the hip arthrosis among people with high exposure to sport is significantly higher compared to those with low exposure (Vingard et al., 1993). The acetabular dysplasia in sportsmen, i.e, small femoral head coverage, additionally increase the probability of hip arthorsis development. During skiing changes in the position of the upper body occur. They are associated with varying degrees of pelvic tilting, which influence the hip joint contact stress distribution (Iglic et al., 1994). The aim of this work was to determine how acetabular dysplasia and pelvic tilt affect the hip joint contact stress distribution after shifting of the upper part of the body towards the weight-bearing leg in slow skiing. METHODS - A three-dimensional model of the hip joint articular surface is used in order to calculate hip joint contact stress distribution (Iglic et al., 1993a). the resultant hip joint force for various body positions is calculated separately by using a static three-dimensional model of the adult hip in the one-legged stance (Iglic et at., 1993b, lglic et al., 1994). RESULTS - It is shown that the decrease of the hip joint contact stress after the shifting of the upper part of the body towards the supporting leg is more effective in the case of large inclination of the pelvis during the shifting og the of the upper part of the body towards the supporting leg hip the stress can be in the case of severe acetabular dysplasia and small inclination of the pelvis even increased in spite of the fact that the resultant hip joint force is considerably reduced. CONCLUSIONS - In accordance with the results of this study it can be concluded that the subjects with borderline acetabular dysplasia should be encouraged to turn during skiing with increased pelvic tilt on the side of the non-weight-bearing leg with simultaneously shifting of the upper part of the body towards the weight-bearing leg. In this way the dysplastic hip is unloaded to an optimum degree. consequently, the risk for arthrosis development is decreased. REFERENCES - Hadley N.A., Brown T.D., Weinstein S.L. (1990) J. Orthop. Res. 8:504-513. lglic A,, Kralj-lglic V., Antolic V., Srakar F., Stanic U. (1993a) IEEE Trans. Rehab. Engr. 1 :207-212. lglic A,, Srakar F., Antolic V. (1993b) Clin. Biomech. 8:223-224. lglic A,, Kralj- lglic V., Antolic V. (1994) Acta Chir. Orthop. Traum. Cech. 61.268- 270. Vingard E., Alfredsson L.. Goldie I., Hoghstedt C. (1 993) Am.J.Sports Med. 21.195-200

Converting Waste into Products and Energy Using Complete Circular Economy and the Hydrogen Effect Technique to Reduce Dependence on Natural Gas

Conversion of waste into products and energy has the potential to reduce CO2 emission through implementation of a complete circular economy and utilisation of the hydrogen effect technique. This study considers the novelties of the hydrogen effect technique, which incorporates an upgraded input unit mathematical model. It includes real-simulated results obtained using an Aspen Plus® simulator, and enlarged production. This technique is developed for optimal municipal solid waste (MSW) combustion, gasification, and reforming, presented as an upgraded input unit for syngas production, which can reduce CO2 emissions by 3·10^6 kmol a–1. This approach is exemplified by utilizing existing methanol and dimethyl ether production processes from natural gas, as they can be achieved and exceeded using MSW with varying hydrogen amounts. The optimal upgraded methanol and dimethyl ether production processes can increase production by 47 % and 16 %, including only the upgraded input unit, as well as decrease the temperature in the product reactors by 30 °C

Transfer of Aflatoxin M1 From the Contaminated Milk Into Cheese and Whey

Aflatoxin M1 is a major metabolite of aflatoxin B1 which is formed when animals ingest contaminated feed. Aflatoxin B1, when ingested by an animal, is rapidly absorbed in the gastrointestinal tract and transformed into a metabolite aflatoxin M1, appearing in the blood after 15 minutes and then secreted in the milk from the mammary gland. Aflatoxin B1 shows hepatotoxic and carcinogenic effects and aflatoxin M1 has a distinct genotoxicity, carcinogenicity and cytotoxicity. The resistance to heat treatment and mild acidic conditions used in the production of cheese or other dairy products (such as, for example, yogurt, cream, butter, and ice cream) has been accounted for the contamination of such products. It is known that aflatoxin M1 is bound to milk proteins, mainly casein, and therefore the toxin is more concentrated in the cheese than in the milk used in cheese production. In practice, aflatoxin M1 can be found in dairy products at levels that are 2-5 times higher than in milk. As a result of the binding of aflatoxin M1 to milk proteins the toxin is distributed more in curd than in whey. Control of samples of milk from the Vojvodina market was conducted during March and April of 2014, in the Dairy Laboratory and Laboratory for the Analysis of Animal Feed and Animal Products, the Department of Animal Science, Faculty of Agriculture, Novi Sad. The method used was HPLC with fluorescence detection with pre-treatment of milk on immunoaffinity columns. The analysis of milk was performed on milk of 12 dairies whose products can be found on the Vojvodina market. The manufacturer with the highest levels of aflatoxin M1 in milk was chosen and a semi-hard cheese was made of such milk. The results showed the expected increase of concentration of aflatoxin M1 in cheese and whey. Since Serbia has no regulation that determines the minimum allowable level of aflatoxin M1 in cheese and other dairy products, the results were compared with acceptable values for cheese in some European countries

History-Dependent Patterns in Randomly Perturbed Nematic Liquid Crystals

We study the characteristics of nematic structures in a randomly perturbed nematic liquid crystal (LC) phase. We focus on the impact of the samples history on the universal behavior. The obtained results are of interest for every randomly perturbed system exhibiting a continuous symmetry-breaking phase transition. A semimicroscopic lattice simulation is used where the LC molecules are treated as cylindrically symmetric, rod-like objects interacting via a Lebwohl-Lasher (LL) interaction. Pure LC systems exhibit a first order phase transition into the orientationally ordered nematic phase at T=Tc on lowering the temperature T. The orientational ordering of LC molecules is perturbed by the quenched, randomly distributed rod-like impurities of concentration p. Their orientation is randomly distributed, and they are coupled with the LC molecules via an LL-type interaction. Only concentrations below the percolation threshold are considered. The key macroscopic characteristics of perturbed LC structures in the symmetry-broken nematic phase are analyzed for two qualitatively different histories at T≪Tc. We demonstrate that, for a weak enough interaction among the LC molecules and impurities, qualitatively different history-dependent states could be obtained. These states could exhibit either short-range, quasi-long-range, or even long-range order

Physical activity and healthy ageing: A systematic review and meta-analysis of longitudinal cohort studies.

BACKGROUND: Older people constitute a significant proportion of the total population and their number is projected to increase by more than half by 2030. This increasing probability of late survival comes with considerable individual, economic and social impact. Physical activity (PA) can influence the ageing process but the specific relationship with healthy ageing (HA) is unclear. METHODS: We conducted a systematic review and meta-analysis of longitudinal studies examining the associations of PA with HA. Studies were identified from a systematic search across major electronic databases from inception as January 2017. Random-effect meta-analysis was performed to calculate a pooled effect size (ES) and 95% CIs. Studies were assessed for methodological quality. RESULTS: Overall, 23 studies were identified including 174,114 participants (30% men) with age ranges from 20 to 87 years old. There was considerable heterogeneity in the definition and measurement of HA and PA. Most of the identified studies reported a significant positive association of PA with HA, six reported a non-significant. Meta-analysis revealed that PA is positively associated with HA (ES: 1.39, 95% CI=1.23-1.57, n=17) even if adjusted for publication bias (ES: 1.27, 95% CI=1.11-1.45, n=20). CONCLUSIONS: There is consistent evidence from longitudinal observational studies that PA is positively associated with HA, regardless of definition and measurement. Future research should focus on the implementation of a single metric of HA, on the use of objective measures for PA assessment and on a full-range of confounding adjustment. In addition, our research indicated the limited research on ageing in low-and-middle income countries