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Purpose: To reduce the rectal radiation dose during local radiation therapy of prostate cancer, a hydrogel spacer is typically implanted between the prostate and rectum. However, the spacer volume can change during external beam radiation therapy (EBRT). Therefore, we used magnetic resonance imaging (MRI) to determine changes in the spacer volume during EBRT and analyzed the data to identify patient factors influencing this change. Materials and methods: A hydrogel spacer was implanted in each enrolled patient diagnosed with prostate cancer (n = 22, age = 69–86 years) for EBRT with a total dose of 70 Gy over 35 fractions. T2-weighted MRI images were acquired before (median = 8 days) and during EBRT, when the radiation dose of 48 Gy (median) was given at 55 days (median) after implantation. MRI images were used to determine the spacer volume as well as the maximum and minimum distances between the prostate and anterior wall of the rectum at the middle height of the prostate. Scatterplots were created to determine whether correlations existed between changes in the spacer volume and these two distances, while uni- and multivariate analyses were conducted to determine if the spacer volume change was influenced by the following patient factors: age, body mass index, estimated glomerular filtration rate, and visceral fat areas at the umbilical and femoral head positions. Results: The spacer volume increased in all 22 patients, with the smaller spacer volume before EBRT increasing by a larger amount during EBRT. This increase in the spacer volume was unaffected by other patient factors. However, it correlated with the change in the maximum distance between the prostate and anterior wall of the rectum. Conclusion: To avoid adverse changes in the rectal radiation dose during EBRT, hydrogel spacer volume should be monitored, especially if the pre-EBRT volume is small. [ABSTRACT FROM AUTHOR]

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Background and Purpose: A high variability of brain MRI volume change measurement renders challenging its interpretation in multiple sclerosis (MS). Occurrence and clinical relevance of observed apparent brain volume increase (BVI) in MS patients have not been investigated yet. The objective was to quantify the prevalence and factors associated with BVI.Methods: We examined 366 MS patients (2,317 scans) and 44 controls (132 scans). Volumetric analysis of brain volume changes was performed by SIENA and ScanView. BVI was defined as brain volume change >0%. We compared characteristics of patients with and without BVI.Results: BVI was found in 26.3% (from 1,951) longitudinal scans (SIENA). If BVI occurred, a probability that BVI will be repeated consecutively more than or equal to two times was 15.9%. The repeated BVI was associated with clinical disease activity in 50% of cases. BVI was associated with shorter time and lower T2 lesion volume increase between two MRI scans, and higher normalized brain volume (all P < .0001). A proportion of scans with BVI was higher when analyzed by ScanView (35.3%) and in controls (36.4% by SIENA).Conclusions: BVI occurs in a great proportion of MR scans over short-term follow-up and is not associated with disease stabilization. Although BVI can be caused by several factors, the results indicate that measurement error may contribute to BVI in the majority of cases. Clinicians should be aware of the frequent occurrence of apparent BVI, interpret brain volume changes in MS patients with great caution, and use methods with precise quantification of brain volume changes. [ABSTRACT FROM AUTHOR]

The freezing of water droplets deposited or impinged on cold surfaces causes many problems in traffic lights, power transmission wires and heat exchangers. Thus, the suppression of the freezing of these droplets is very important. In this study, we carried out two-dimensional numerical simulation on the freezing of the water droplets on a horizontal cold surface using a Phase-field method. A new equation was developed to predict an increase in the total volume of the droplets due to the freezing. The changes in the physical properties of supercooled water with temperature were taken into account for an impinged droplet. The computational results for deposited droplets showed that a projection was formed on the cap of a frozen droplet and that the volume of ice was 8.8% higher than the volume of a deposited water droplet in its unfrozen state. However, the change in the mass due to the freezing was less than 0.001%. Also, a concave shape of the freezing front was predicted after an ice layer was formed. This was consistent with the results for freezing droplets observed by other researchers. Moreover, similar results were obtained in the case of impinged droplets. With these, a projection was formed. The volume of ice was 8.1% higher than the volume of the impinging droplet in the air, while the change in the mass was less than 0.0023%. The predicted freezing fronts were similar to that observed in previous studies.

Thin coatings based on liquid crystal networks (LCNs) modified with azobenzene moieties are able to create dynamic surface topographies in the micrometre range by exposure with UV light. The surface corrugations can be erased and restored by switching ‘off’ and ‘on’ the UV illumination. Various configurations were presented. The formation of the protrusions was proven to be induced mainly by excessive volume formation when the order in the LCNs is reduced. It is suggested that this extra volume formation can be further enhanced by stimulating the oscillatory dynamics oftrans-cisandcis-transisomerisation. Therefore, dual-wavelength exposure not only exciting thetransstate of azobenzene by 365 nm UV light but simultaneously also thecisstate by 455 nm blue light was shown to enhance the effect. [ABSTRACT FROM PUBLISHER]

Craniopharyngiomas are rare embryonic tumors with low grade of malignancy that arise in supra-or intra-sellar areas with severe ophthalmological, neurological, and endocrine damages. Among pituitary deficits, somatotroph and gonadotroph deficiencies are the most challenging because of potential increased risk of tumor growth and recurrence. While data exist to suggest that growth hormone (GH) treatment is safe, very little is known about sex hormones replacement on tumor growth. Our aim was to report 3 craniopharyngiomas with tumor increase under GH and/or estrogen (E2) therapy. The three patients, aged 21, 22, and 23, were studied for severe short stature related to calcified ( n = 1) or apparently stable (for more than 2 years) craniopharyngiomas with somatotroph and gonadotroph deficiencies. After 4 months to 1 year GH ( n = 2) and/or E2 replacement ( n = 3), there was an increase in craniopharyngiomas-size with signs of intracranial hypertension in two cases. In our three craniopharyngiomas that were either totally calcified or stable before substitution, the tumor increase seemed to be the result of GH and/or E2 substitution. But, as spontaneous evolution of these tumors is unpredictable, we could not exclude a mere coincidence. [ABSTRACT FROM AUTHOR]

A new technique for the online observation of rheological data of hydrogels during experiments involving significant volume changes is proposed. In order to accommodate for large volume changes, the gap has to be force controlled and continuously adjusted to the current sample height. Furthermore, the force control also has to ensure the adhesion of the sample to the geometry. For smaller volume changes, it is also possible to employ experiments with constant gap. Due to the volume change, the sample is not clearly defined with respect to the open surfaces in a parallel plate geometry, which leads to too high values, which, however, can be compensated for properly. [ABSTRACT FROM AUTHOR]

Vacuoles of several types can be observed in pollen throughout its development. Their physiological significance reflects the complexity of the biological process leading to functional pollen grains. Vacuolisation always occurs during pollen development but when ripe pollen is shed the extensive translucent vacuoles present in the vegetative parts in previous stages are absent. Vacuole functions vary according to developmental stage but in ripe pollen they are mainly storage sites for reserves. Vacuoles cause pollen to increase in size by water accumulation and therefore confer some degree of resistance to water stress. Modalities of vacuolisation occur in pollen in the same manner as in other tissues. In most cases, autophagic vacuoles degrade organelles, as in the microspore after meiosis, and can be regarded as cytoplasm clean-up following the transition from the diploid sporophytic to the haploid gametophytic state. This also occurs in the generative cell but not in sperm cells. Finally, vacuoles have a function when microspores are used for pollen embryogenesis in biotechnology being targets for stress induction and afterwards contributing to cytoplasmic rearrangement in competent microspores. [ABSTRACT FROM AUTHOR]

In the Dingwall gypsum quarry in Nova Scotia, Canada, operating in 1933–1955, the bedrock anhydrite deposits of the Carboniferous Windsor Group have been uncovered from beneath the secondary gypsum beds of the extracted raw material. The anhydrite has been subjected to weathering undergoing hydration (gypsification), transforming into secondary gypsum due to contact with water of meteoric derivation. The ongoing gypsification is associated with a volume increase and deformation of the quarry bottom. The surface layer of the rocks is locally split from the substrate and raised, forming spectacular hydration relief. It shows numerous domes, ridges and tepee structures with empty internal chambers, some of which represent unique hydration caves (swelling caves, Quellungshöhlen). The petrographic structure of the weathering zone has been revealed by macro- and microscopic observations. It was recognized that gypsification commonly starts from a developing network of tiny fractures penetrating massive anhydrite. The gypsification advances from the fractures towards the interior of the anhydrite rocks, which are subdivided into blocks or nodules similar to corestones. Characteristic zones can be recognized at the contact of the anhydrite and the secondary gypsum: (1) massive and/or microporous anhydrite, (2) anhydrite penetrated by tiny gypsum veinlets separating the disturbed crystals and their fragments (commonly along cleavage planes), (3) gypsum with scattered anhydrite relics, and (4) secondary gypsum. The secondary gypsum crystals grow both by replacement and displacement, and also as cement. Displacive growth, evidenced by abundant deformation of the fragmented anhydrite crystals, is the direct cause of the volume increase. Crystallization pressure exerted by gypsum growth is thought to be the main factor generating volume increase and, consequently, also the formation of new fractures allowing water access to "fresh" massive anhydrite and thus accelerating its further hydration. The expansive hydration is taking place within temperature range from 0 to ~30 °C in which the solubility of gypsum is lower than that of anhydrite. In such conditions, dissolving anhydrite yields a solution supersaturated with gypsum and the dissolution of anhydrite is simultaneous with in situ replacive gypsum crystallization. Accompanying displacive growth leads to volume increase in the poorly confined environment of the weathering zone that is susceptible to upward expansion. [ABSTRACT FROM AUTHOR]

A device for measuring the short-term fluctuations in volume of individual tubers is described. Its accuracy is mostly independent of tuber growth stage, shape and malformations. The coefficient of variation of volume of a tuber of 40 cm was usually well below 0.15% when the tuber was measured four times. [ABSTRACT FROM AUTHOR]

• ESA-induced deterioration of concrete is divided into dormant and detrimental periods. • An integrated macro-microscopic model for concrete deterioration is developed. • Diffusion, reaction of sulfate and its-induced expansion of concrete can be analyzed. • Deterioration process of concrete pipe exposed to Na 2 SO 4 solution is investigated. Concrete deterioration caused by external sulfate attack (ESA) is a macro-microscopically interactive expansion process, including two stages, namely a dormant period and detrimental duration. Based on ESA-induced deterioration mechanism, an integrated macro-microscopic model has been developed to describe the deterioration of concrete. In this model, a critical characteristic related to crystallization pressure is proposed to recognize two stages of ESA, and a criterion of ESA-induced boundary movement in concrete specimen is established by its total damage associated with micro and macroscopic damages. A diffusion-reaction model is constructed to characterize macroscopic sulfate diffusion and microscopic ettringite/gypsum formation in concrete, which are respectively used to determine the crystallization pressure and volume increase. The macro and microscopic mechanical models, combining with the plastic-damage model, are built to analyze the expansion-induced deterioration of concrete. The integrated model is validated by the experimental results of expansion deformation and damage distribution. [ABSTRACT FROM AUTHOR]

Research on human brain changes during skill acquisition has revealed brain volume expansion in task-relevant areas. However, the large number of skills that humans acquire during ontogeny militates against plasticity as a perpetual process of volume growth. Building on animal models and available theories, we promote the expansion-renormalization model for plastic changes in humans. The model predicts an initial increase of gray matter structure, potentially reflecting growth of neural resources like neurons, synapses, and glial cells, which is followed by a selection process operating on this new tissue leading to a complete or partial return to baseline of the overall volume after selection has ended. The model sheds new light on available evidence and current debates and fosters the search for mechanistic explanations., (Copyright © 2017 Elsevier Ltd. All rights reserved.)