Authors:A. Özer, Selcan Turker, Seyda Çolak, Mustafa Korkmaz, Ekrem Kiliç, and Meral Özalp
The use of gamma rays for the sterilization of pharmaceutical raw materials and dosage forms is an alternative method for sterilization. However, one of the major problems of the radiosterilization is the production of new radiolytic products during the irradiation process. Therefore, the principal problem in radiosterilization is to determine and to characterize these physical and chemical changes originating from high-energy radiation. Parenteral drug delivery systems were prepared and in vitro characterization, biodistribution and treatment studies were done in our previous studies. Drug delivery systems (liposomes, niosomes, lipogelosomes and niogelosomes) encapsulating diclofenac sodium (DFNa) were prepared for the treatment of rheumatoid arthritis (RA). This work complies information about the studies developed in order to find out if gamma radiation could be applied as a sterilization method to DFNa, and the raw materials as dimyristoyl phosphatidylcholine (DMPC), surfactant I [polyglyceryl-3-cethyl ether (SUR I)], dicethyl phosphate (DCP) and cholesterol (CHOL) that are used to prepare those systems. The raw materials were irradiated with different radiation doses (5, 10, 25 and 50 kGy) and physicochemical changes (organoleptic properties pH, UV and melting point), microbiological evaluation [sterility assurance level (SAL), sterility and pyrogen test] and electron spin resonance (ESR) characteristics were studied at normal (25 °C, 60% relative humidity) and accelerated (40 °C, 75% relative humidity) stability test conditions.
Indoor air quality is a major part of indoor environmental quality and plays an important role in creating sustainable and healthy indoor environments. Well-being, health and comfort are affected by indoor air quality. The measurements that are introduced in this research paper were used to record the results of three different residential interiors. These data are a part of a larger scale research project that included the evaluation of residential buildings, offices, university interiors and for instance nurseries. The reason behind conducting the measurements in these interiors was that in all of the examples inadequate indoor air quality and therefore human discomfort, illness and also building failure occurred.
In this paper the theoretical background of the research and the measurement of indoor air quality (indoor air temperature, relative humidity level and carbon dioxide level) will be introduced. The poor indoor air quality in these buildings is a result of a complex system. The thermal bridges of the facade cause cold interior surfaces, the airtight solutions cause high relative humidity levels. These two combined result in mould appearance. Besides, the lack of appropriate ventilation rate can be the third part of the reason behind poor indoor air quality.
Based on the results of the measurement data, different solutions are suggested in each case to improve indoor environmental and air quality, in accordance with creating healthier indoor environments.
An impact of temperature, light and relative humidity were studied on root colonisation by mycorrhizal fungi and on pine seedling growth. Moderate and high light intensities favoured mycorrhizal colonisation and seedling growth. Pine seedlings inoculated with
compared to other fungi attained maximum growth. Survival of pine seedlings was higher under moderate light intensity than low and high light intensity. Seedling growth and mycorrhizal colonisation was better at 25°C than 10°C. Variation in humidity did not show much difference in mycorrhizal colonisation and seedling growth. However, seedling survival was greater at high than at low humidity. Pine seedlings showed best survival with 0.5 P level (46.153 mg P/kg soil) of phosphorus at 25 °C temperature and under moderate light intensity. Among the mycorrhizal fungi used
was the most effective endophyte and was followed by
Laccaria laccata, Rhizopogon luteolus
under various physical factors.
Airborne concentration levels of222Rn and its progeny, and220Rn progeny were measured in an underground U mine. In addition, concurrent measurements of several meteorological variables such as temperature, relative humidity, barometric pressure and airflow rate were also carried out. Mining operations and mining activities during the measurements were carefully noted. The data collected show great variability. Although not particularly strong, some definite correlations could be found between airborne radioactivity concentration levels, meteorological variables, and mining operations (and mining activities). The difficulty in obtaining stronger correlations between the above variables is attributed to the great and simultaneous variability of most of the variables measured. The data presented here are typical of active U–Th mining environments, i.e., of Ontario (Canada) underground U mines. Measurements extended for a period of a full calendar year and involved several thousand independent measurements.
A method is proposed which, through the monitoring and modeling of the diurnal variation of α-radioactivity in the air near
the ground, appears with a potential in enhancing the measurement of low radioactivity unexpected peaks over the natural background.
Portable field instrumentation was used for the monitoring which further included the total γ-radiation at ground level, the
relative humidity and temperature. The variation of the α-radioactivity follows a periodic form with peaks in the morning
and in the afternoon. The applicability of a mathematical model to describe this variation of the α-radioactivity in terms
of the meteorological variables and the γ-radiation was tested positive. This could reduce the difference between the measured
and modeled periodic variation to an almost flat one, above which sudden unexpected peaks of radioactivity from possible undeclared
nuclear activities could be easier identified.
Authors:M. Odlyha, Q. Wang, G. M. Foster, J. de Groot, M. Horton, and L. Bozec
Dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and thermogravimetry (TG) have been used
to characterise model tapestries, especially woven for the EC-funded project (MODHT) and to historic tapestries in royal palaces
and museums. Modulus values of woollen threads from model tapestries are reported and the effects of traditional dyeing and
mordanting processes quantified. TG, particularly of black woollen threads showed alterations in thermal stability. Tests
of creep on immersion in water and subsequent heating to 90C and on exposure to a controlled relative humidity programme
were also used to rank these effects. Modulus values of historic woollen samples were also obtained and DSC studies of model
and historic silk samples are reported together with preliminary atomic force microscopy (AFM) images of silk fibres.
Authors:A. Bigi, M. Borghi, G. Cojazzi, A. Fichera, S. Panzavolta, and N. Roveri
Differential scanning calorimetry and high angle X-ray diffraction analyses were performed on gelatin films, air dried at
different values of constant elongation, crosslinked with glutaraldehyde and examined at constant relative humidity of 75%.
Drawing induces a preferential orientation of the chain segments of gelatin parallel to the stretching direction,and a linear
increase of the renaturation level, calculated as the ratio between the denaturationenthalpy of gelatin films and that of
tendon collagen. The comparison with the results previously obtained on the mechanical properties of the films, puts into
evidence the different contributions of orientation and renaturation on the improvement of the mechanical parameters on drawing.
The results offer important information on the role of glutaraldehyde (GTA) crosslinking on the stability of collagenous materials.
Differential scanning calorimetry (DSC) has been used to probe ordered structures and glassing behaviour for a range of agars containing < 25% w/w water. Most commercial agars are supplied in an ordered (double-helical) state, show an endothermic helix-to-coil transition above 100‡C at low-moisture, and require 90–100‡C for solubilisation in excess water. Agars dried from the coil (single-chain) state show no corresponding endothermic transitions and only require a minimum of 45‡C for aqueous dissolution. Evidence from helix-to-coil transition enthalpies, equilibrium water content as a function of relative humidity, and solid-state13C NMR spectroscopy suggests that water molecules are associated enthalpically with double-helical agar. Single-chain agar is apparently not obtained in a glassy state by direct drying from solution, but in common with double-helical forms, exhibits rubber/glass transition behaviour following heating (in a DSC pan) to 180‡C.
Authors:L. Barral, J. Cano, A. J. López, J. López, P. Nogueira, and C. Ramírez
The diffusive and dynamic mechanical behavior of the DGEBA/1,3-BAC epoxy resin system was studied during water absorption. The diffusion of water was investigated at 100% relative humidity, by immersion of specimens in water at 60, 80 and 100°C. In all absorption experiments, water diffusion followed Fick's law. Diffusion coefficients and saturated water concentrations are given for these temperatures. The activation energy for diffusion was determined from the relationship between the diffusion coefficient and the reciprocal of the absolute temperature. The value obtained was 31.2 kJ mol−1. Dynamic mechanical analysis of samples immersed in 100°C water and with various water contents showed both a shift of Tg, defined by thetanδ peak, to lower temperatures and a slight decrease in the dynamic modulus in the presence of water. These effects are probably a result of plasticization.
Authors:M. Marečić, F. Jović, V. Kosar, and V. Tomašić
This work deals with the photocatalytic oxidation of toluene at room temperature and atmospheric pressure in the gas phase. The differential equations of the reactor model are solved numerically with simultaneous estimation of the model parameters. Estimation of the kinetic data is performed using a modified differential method of data analysis and a Nelder–Mead method of nonlinear optimization for parameter estimation. The reaction is performed in an annular photoreactor using UVA black light blue fluorescent lamp. The experiments are carried out at different total flow rates of the reaction feed (20–160 cm3 min−1), two different inlet concentrations of toluene (2.67 and 5.24 g m−3) and at constant relative humidity (25%). A good agreement between the experimental data and theoretical predictions is obtained, supporting the applicability of the proposed models to describe the investigated process performed in laboratory annular photoreactor.