Two reference halloysites from New Zealand (Te Puke and Opotiki) were studied by X-ray diffraction under (1) various levels of relative humidity (RH) from 95 to 0% (dehydration), and (2) various temperatures increasing from 25 to 120°C (dehydration). They were also studied by differential thermal and thermogravimetric analyses at 40 and 0.2% RH. The impact of freeze drying along with the influence of cation saturation (Ca and K) on halloysite hydration were studied. The dehydration of the two halloysite samples upon decrease in RH started below 70% RH. However, the dehydration of Opotiki was still incomplete at ∼0% RH regardless of the saturation cation whereas Te Puke was completely dehydrated at ∼10% RH. For each sample, the decrease in RH and the increase in temperature induce similar dehydration behavior, but the dehydration processes of the Opotiki and Te Puke samples are different. The dehydration of Te Puke proceeds with one intermediate hydration state reacting as a separate phase due to the presence of ‘hole’ water molecules. The dehydration of the fully hydrated Opotiki halloysite gives a dehydrated phase and no 8.6 Å phase. The results suggest the presence of different types of water molecule, the ‘associated’ and the ‘hole’ water, controlling the dehydration behavior of halloysites. Freeze-dried halloysite samples are essentially dehydrated and the size of their coherent scattering domains is strongly reduced. Rehydration experiments performed after dehydration either at 95% RH or by immersing the sample in water for 3 months result in their partial rehydration. Calcium saturation promotes the rehydration process. The results suggest the presence of interlayer cations in the Opotiki sample, Ca ions being associated with the strongly held ‘hole’ water. As a result of this study, we assert that the (de)hydration behavior of halloysite is highly heterogeneous and cannot be generalized a priori.

The Hançılı bentonite from Turkey shows significant changes in surface area, micro- and mesoporosity, surface acidity and acid strength with heating from 100 to 900°C for 2 h. The specific surface area (S) and specific micro-mesopore volume (V) of the original and heated samples were evaluated from N2 adsorption and desorption data, respectively, by standard methods. The adsorption of n-butylamine from the solution in cyclohexane on the samples was used to determine the total surface acidity (nm) and the adsorption equilibrium constant (K) was taken as a measure of the acid strength. S, V and nm having initial values of 98 m2g−1, 0.080 cm3g−1 and 4.8 × 10−4 mol g−1, respectively, stayed approximately constant as the temperature increased to 450°C and then decreased almost in parallel with each other, reaching their minimum or zero at 900°C. The total surface acidity, in general, declines with increasing temperature. The most acidic sites, however, increase with heating, and especially at dehydration and dehydroxylation. Acid strength reaches its maximum during the dehydroxylation phase at ∼600°C. It was concluded that the total surface acidity does not necessarily parallel the strength of the most acid sites.

A new method for identifying the trioctahedral smectites saponite, stevensite and hectorite is proposed in this study. The method is based on differences in the X-ray diffraction (XRD) patterns of the three smectites after (a) heating at 500°C for 90 min and (b) glycerol solvation of the Cs-forms of the smectites for 20 h. After heating at 500°C, well below the dehydroxylation temperature of the three smectites, saponite and hectorite re-expand upon ethylene glycol (EG) solvation, whereas stevensite layers remain collapsed. Saponite forms one-layer and hectorite two-layer complexes after Cs-saturation and glycerol solvation. Cs-stevensite displays a gradual increase in d001 with increasing solvation time in glycerol vapours and forms two-layer glycerol complexes with prolonged solvation. Except for the individual Mg-smectites, the proposed method may be used to identify compositional heterogeneity that may exist in the smectites. Furthermore, it should be useful in identifying the individual trioctahedral Mg-smectites when present in mixtures, and in detecting interstratified layers of different Mg-trioctahedral smectites. Application of the method revealed that the SYnL-1 laponite (CMS Source Clay Project) is not homogeneous but consists of hectorite, stevensite and possibly mixed-layer hectorite/stevensite layers.

The Fe oxide mineralogy behind the reddish colour (up to Munsell 10R) of a soil and four Quaternary surface deposits from central Jutland (Denmark) was investigated by XRD, TEM, Mo¨ssbauer spectroscopy and bulk saturation magnetization. The red soil (Naesset) consists of a 1 m deep patch, ∼10 m2 in area. It is one of at least 5 –10 isolated spots of limited size which contain hematite and maghemite, and are probably due to local fire.

The four more extended (several hundred m2) red sediments (Salten Skov, Salten, Pot Molle and Laasby) all occur at the feet of slopes and formed from Fe2+-containing seepage water. They contain 25 – ∼100% Fe oxides, originally consisting of ferrihydrite. The well-drained parts of the deposits are at present all dominated by goethite. Hematite and maghemite were also identified at two sites in the top ∼25 cm, one site containing goethite and hematite and probably a little maghemite, and the other goethite and probably hematite. The presence of hematite and particularly maghemite in the surface sediments could be explained by heating of goethite. However, there is no historic or prehistoric evidence of heating activity, and the spatial extension is much wider than that of normal human events. In contrast to the burned soil site, goethite is still present in the upper layers together with a high content of organic matter. Thus, although the present belief is that the deposits formed by heating, site evidence is to the contrary.

Extensive drying of smectites can cause the interlayer space to break down (collapse). This can affect the properties of bentonites as geotechnical barriers of HLRW (highly radioactive waste) repositories. If and to what extent the collapse occurs depends strongly on the type of interlayer cation. In particular K is known to lead to ready dehydration, in contrast to Ca and Mg. In the present study, various bentonites and one illite/smectite clay were dried/heated at 90ºC for 1.5 a and in a different experiment at 120ºC for 4.5 a and investigated with respect to mineralogical and geochemical changes of the smectite.

Smectite alteration after extensive drying was restricted to changes of the exchangeable cations. The CEC decreased by 9% (90ºC test) and 14% (120ºC test). A slight decrease of exchangeable Na+ was observed following the 90ºC test. No significant further decrease was observed after the 120ºC test. In contrast, the larger cation exchange capacity (CEC) decrease after the 120ºC test could be explained by increased Ca/Mg fixation. A possible mechanism for the observations is presented.

Fresh and weathered pyrochlore from the Lueshe carbonatite complex (in the northeast of the Democratic Republic of Congo) was studied by Fourier transfom infrared (FTIR) spectroscopy and by a combination of FTIR spectroscopy and thermal analysis. The former was carried out in the spectral range 400–4000 cm−1. The spectra for fresh and weathered pyrochlores were very different. For the weathered pyrochlore, two bands were identified as OH vibration modes, one broad band with a maximum at 3413 cm−1 and another finer band at 1630 cm−1. The fresh pyrochlore does not show OH absorption bands. The presence of OH confirms the hydrated state of the weathered pyrochlore suggested by previous microanalytical work. The combination of FTIR spectroscopy and thermal analysis allows ‘real-time’ observation of gas emanations and solid-state transformations taking place during heating up to 800°C. For fresh pyrochlore, no solid transformation was detected, except a CO2 emanation from 242–576°C. For the weathered pyrochlore a dehydration was observed between 234–565°C followed by an exothermic peak in Differential Scanning Calorimetric (DSC) curve at 604°C. This exothermic peak corresponds to the formation of a Nb oxide phase. At higher temperatures the weathered pyrochlore is partly decomposed, forming a dehydrated pyrochlore and a Nb oxide phase. The combination of FTIR and thermal analysis has provided useful information on both fresh and weathered pyrochlore transformations which has clarified our understanding of the water control of the structural stability of pyrochlore minerals.

Efforts to screen and mass-rear insects and diseases for leafy spurge biocontrol agents have been hampered by low success in propagation and slow growth of leafy spurge in the greenhouse. The optimum greenhouse conditions for leafy spurge growth were determined. Leafy spurge was propagated from stem tip cuttings, with the basal end treated with 0.2% NAA, and the plants misted with water for 10 d. Optimum conditions for growth were 27 C air temperature, application of a complete fertilizer at 70 kg ha−1 weekly or 135 kg ha−1 biweekly 20 d after stem tip propagation, in a peat/perlite/vermiculite growth medium at pH 7 and a 16-h photoperiod. Regrowth from roots of parent plants was improved when cuttings were taken from plants at least 60 d old, and plants grew nearly twice as rapidly when the medium was maintained at 30 C compared to 22 C. Refrigeration of stem tip cuttings or roots before planting did not affect survival or growth vigor. Only gibberellic acid of nine plant growth regulators evaluated increased growth, but plants were etiolated. Biotypes from Nebraska and South Dakota were shorter than five others from the United States or Austria but had similar root and shoot dry weight. The time required to propagate vigorous leafy spurge was reduced to 2 mo compared to 6 mo required prior to the study.

The objective of the research presented in this paper was to investigate how different characteristics of whey protein microparticles (MWP) added to milk as fat replacers influence intermolecular interactions occurring with other milk proteins during homogenisation and heating. These interactions are responsible for the formation of heat-induced aggregates that influence the texture and sensory characteristics of the final product. The formation of heat-induced complexes was studied in non- and low-fat milk model systems, where microparticulated whey protein (MWP) was used as fat replacer. Five MWP types with different particle characteristics were utilised and three heat treatments used: 85 °C for 15 min, 90 °C for 5 min and 95 °C for 2 min. Surface characteristics of the protein aggregates were expressed as the number of available thiol groups and the surface net charge. Intermolecular interactions involved in the formation of protein aggregates were studied by polyacrylamide gel electrophoresis and the final complexes visualised by darkfield microscopy. Homogenisation of non-fat milk systems led to partial adsorption of caseins onto microparticles, independently of the type of microparticle. On the contrary, homogenisation of low-fat milk resulted in preferential adsorption of caseins onto fat globules, rather than onto microparticles. Further heating of the milk, led to the formation of heat induced complexes with different sizes and characteristics depending on the type of MWP and the presence or not of fat. The results highlight the importance of controlling homogenisation and heat processing in yoghurt manufacture in order to induce desired changes in the surface reactivity of the microparticles and thereby promote effective protein interactions.

An important factor in controlling invasive plant infestations is frequently the acceleration of the deterioration of their persistent seed bank, which is often associated with physical dormancy mechanisms. We hypothesized that breaking dormancy by heat would enhance the vulnerability of the nondormant seeds to hydrothermal stresses. The aim of the present study was to examine the effect of soil solarization treatments (heating the soil by means of polyethylene mulching) on buried Australian Acacia seeds, with emphasis on Acacia saligna L. The results of three field experiments indicate that soil solarization treatments caused an almost complete eradication of buried seeds of Acacia saligna and two other Australian Acacia species, Acacia murrayana and Acacia sclerosperma. The killing mechanism of solarization was further studied in laboratory experiments. We observed two phases of the heat-induced deterioration of seed persistence: breaking the dormancy of the seeds and exposing the “weakened seeds” to lethal temperatures. From an ecological perspective of conservation, the present study shows for the first time the possible utilization of solar energy, by means of soil solarization, for reducing persistent seed banks of invasive woody plants.

Prevention of the heat-induced aggregation of β-lactoglobulin (β-Lg) would improve the heat stability of whey proteins. The effects of lipoic acid (LA, or thioctic acid), in both its oxidised and reduced form (dihydrolipoic acid, DHLA), on heat-induced unfolding and aggregation of β-Lg were investigated. LA/DHLA was added to native β-Lg and the mixture was heated at 70, 75, 80 or 85 °C for up to 30 min at pH 6·8. The samples were analysed by Polyacrylamide Gel Electrophoresis (PAGE) and Size-exclusion HPLC (SE-HPLC). LA was not as effective as DHLA in reducing the formation of aggregates of heated β-Lg. Heating β-Lg with DHLA resulted in formation of more β-Lg monomers (due to dissociation of native dimers) and significantly less β-Lg aggregates, compared with heating β-Lg alone. The aggregates formed in the presence of DHLA were both covalently linked, via disulphide bonds, and non-covalently (hydrophobically) linked, but the amount of covalently linked aggregates was much less than when β-Lg was heated alone. The results suggest that DHLA was able to partially trap the reactive β-Lg monomer containing a free sulphydryl (−SH) group, by forming a ‘modified monomer’, and to prevent some sulphydryl−sulphydryl and sulphydryl−disulphide interactions that lead to the formation of covalently linked protein aggregates. The effects of DHLA were similar to those of N-ethylmaleimide (NEM) and dithio(bis)-p-nitrobenzoate (DTNB). However, the advantage of using DHLA over NEM and DTNB to lessen aggregation of β-Lg is that it is a food-grade compound which occurs naturally in milk.

Bovine colostrum and milk antibodies of calving and lactating cows immunized with a multivalent vaccine consisting of whole cells of three different species of pathogenic bacteria including four strains of enterotoxigenic Escherischia coli, five strains of enteropathogenic Esch. coli, three strains of enteroinvasive Esch. coli, two strains of Samonella typhi, and one strain each of Shigellia dysenteriae, Sh. sonnei and Sh. flexneri were generated, respectively. A significantly elevated activity and titre of specific IgG from bovine immune colostrum were seen for only 5 days after calving of immunized cows, however, the levels of specific IgG could be obtained continuously from the milk of immunized lactating cows until the 11th week of the entire experiment period. Subsequently, we observed that the high specific IgG activity in immune milk was relatively stable under pH 5·0–7·0 at 37°C. Of importance, we identified that the specific IgG preserved its biological function for high antigen-binding activity at pH 5·5–6·5 for 30 min of heat treatment at 70°C and for 350 s at 72°C. Our findings suggest that the specific IgG from milk antibodies of immunized lactating cows may be used as an abundant source of hyper-immune products for prevention of multibacteria-induced diarrhea, however, the effect of pH on its antigen-binding activity upon heating should be carefully considered and designed.

High frequency acoustic waves have been suggested as a source of mechanical heating in the quiet solar chromosphere. To investigate this, we have observed intensity oscillations of several lines in the frequency interval 1.64-70mHz using data from the VTT Tenerife and the Dunn Solar Telescope at the National Solar Observatory. Our analysis of Fe i 543.45 nm, Fe i 543.29 nm and the G-band, indicate that the majority of oscillations are connected with the magnetic fields and do not provide sufficient mechanical flux for the heating of the chromosphere. This correlation is also observed in quiet Sun areas.

Dormancy in seeds of Dodonaea viscosa is due to a water-impermeable seed coat (physical dormancy, PY). Thus, mechanically scarified seeds imbibed water (c. 95% increase in mass) and germinated to high percentages over a wide range of temperature regimes in both white light and darkness, whereas non-scarified seeds did not take up water. Dry heat at 80–160°C and dipping in boiling water for 1–60 s also broke dormancy in a high percentage of the seeds, and continuous far-red light was not inhibitory to germination. However, dry storage in the laboratory for >1 year did not overcome dormancy. Seeds made water-permeable by boiling imbibed water, and thus germinated, at a much slower rate than those made water-permeable by mechanical scarification. We suggest that boiling opened the ‘water gap’ in the seed coat (not yet described in Sapindaceae but present in other taxa with PY) and that water entered the seed only through this small opening, thereby accounting for the slow rate of imbibition and subsequent germination. Physical dormancy has now been shown to occur in seeds of this polymorphic, worldwide species from Australia, Brazil, Hawaii, Mexico and New Zealand. The low level of dormancy reported for seed lots of D. viscosa in China, India and Pakistan is probably due to collection of seeds before they dried to the critical moisture content for development of water-impermeability of the seed coat. Germination of non-dormant seeds over a wide range of temperatures and in white light, far-red (leaf-canopy shade) light and darkness are part of the germination strategy of D. viscosa and of other taxa whose seeds have PY at maturity.

Human immunodeficiency virus (HIV) can be inactivated by heating at 56 °C for 30 min, treating with 50% ethanol at room temperature for 10 min, or treating with 2% sodium hypochlorite solution (NaClO) at room temperature for 60 min. Using a mouse model, we evaluated the risk of generating chromosome damage in spermatozoa following these treatments. The spermatozoa were all dead after the treatments. Although 41.3% of oocytes injected with ethanol-treated spermatozoa successfully activated, none of the oocytes injected with heated or NaClO-treated spermatozoa activated. When artificial stimulation with strontium was used, the fertilization of oocytes with heated or ethanol-treated spermatozoa was completely rescued. Sperm nuclei treated with NaClO neither decondensed nor developed to a male pronucleus. The incidences of structural chromosome aberrations in 1-cell zygotes derived from the heated spermatozoa (45.6%) and ethanol-treated spermatozoa (91.2%) were significantly higher than those in the matched controls (5.5% and 10.5%, respectively). Further study is needed to develop a methodology for the protection of spermatozoa against chromosome damage or the separation of damaged spermatozoa before intracytoplasmic sperm injection.

The present study was designed to examine the effects of overheating on meiotic spindle morphology within in vitro matured human oocytes using a polarized light microscope (Polscope). Immature human oocytes at either germinal vesicle or metaphase I stage were cultured in vitro for 24–36 h until they reached metaphase II (M-II) stage. After maturation, oocytes at M-II stage were imaged in the living state with the Polscope at 37, 38, 39 and 40 °C for up to 20 min. After heating, oocytes were returned to 37 °C and then imaged for another 20 min at 37 °C. The microtubules in the spindles were quantified by their maximum retardance, which represents the amount of microtubules. Spindles were intact at 37 °C during 40 min of examination and their maximum retardance (1.72–1.79) did not change significantly during imaging. More microtubules were formed in the spindles heated to 38 °C and the maximum retardance was increased from 1.77 before heating to 1.95 at 20 min after heating. By contrast, spindles started to disassemble when the temperature was increased to 39 °C for 10 min (maximum retardance was reduced from 1.76 to 1.65) or 40 °C for 1 min (maximum retardance was reduced from 1.75 to 1.5). At the end of heating (20 min), fewer microtubules were present in the spindles and the maximum retardance was reduced to 0.8 and 0.78 in the oocytes heated to 39 °C and 40 °C, respectively. Heating to 40 °C also induced spindles to relocate in the cytoplasm in some oocytes. After the temperature was returned to 37 °C, microtubules were repolymerized to form spindles, but the spindles were not reconstituted completely compared with the spindles imaged before heating. These results indicate that spindles in human eggs are sensitive to high temperature. Moreover, maintenance of an in vitro manipulation temperature of 37 °C is crucial for normal spindle morphology.