Stabilisation of waterlogged archaeological wood: the application of structured-light 3D scanning and micro computed tomography for analysing dimensional changes.

Cultural heritage objects made of wood can be preserved under waterlogged conditions for many years, where decay is slowed down and the wood structure is more or less completely filled with water. Depending on the degree of degradation, finds may collapse and shrink when they are allowed to dry in an uncontrolled manner after excavation, leading to total loss of the object and its information. Conservation measures are taken to prevent damage of objects and dimensional stability is an important criterion. In this study, structured-light 3D scanning and micro-computed tomography were used to analyse the dimensional stability of wood after conservation, as well as its long-term stability. 83 samples from a reference collection established between 2008 and 2011 allowed this comparative study of the most common conservation methods at that time. The effects of conservation methods using alcohol-ether resin, melamine-formaldehyde (Kauramin 800®), lactitol/trehalose, saccharose, and silicone oil on dimensional stability were investigated. In addition, different polyethylene glycol (PEG) treatments with subsequent freeze-drying were also investigated: one-stage with PEG 2000, two-stage with PEG 400 and PEG 4000 and three-stage with PEG 400, PEG 1500 and PEG 4000. The data received from analyses of both volume and surface gave detailed information about the success of each conservation method. Attempts were made to quantify the damage patterns, specifically shrinkage, collapse, and cracks. While PEG and freeze-drying, alcohol-ether-resin, as well as the Kauramin 800® method gave the best results, analysis also highlighted the failures of each method.

Impact of stress and levels of corticosterone on the development of breast cancer in rats.

Stress is experienced during cancer, and impairs the immune system's ability to protect the body. Our aim was to investigate if isolation stress has an impact on the development of tumors in rats, and to measure the size and number of tumors and the levels of corticosterone. Breast cancer was induced in two groups of female rats (N=20) by administration of a single dose of N-methyl-N-nitrosourea 50 mg/kg. Rats in the control group (cancer induction condition) were allowed to remain together in a large cage, whereas in the second group, rats were also exposed to a stressful condition, that is, isolation (cancer induction and isolation condition, CIIC). The CIIC group displayed anxious behavior after 10 weeks of isolation. In the CIIC group, 16 tumors developed, compared with only eleven tumors in the control cancer induction condition group. In addition, compared with the control group, the volume of tumors in the CIIC group was greater, and more rats had more than one tumor and cells showed greater morphological damage. Levels of corticosterone were also significantly different between the two groups. This study supports the hypothesis that stress can influence the development of cancer, but that stress itself is not a sufficient factor for the development of cancer in rats. The study also provides new information for development of experimental studies and controlled environments.

Morphometric assessment of the lumbar pedicle isthmus by reformatted CT: variations according to age and gender

This work aims to determine the morphometric characteristics of the lumbar pedicle isthmus with surgical relevance to transpedicular procedures using reformatted computed tomography (CT) and to determine the possible variations in the diameters between genders and age groups. Observational, cross-sectional, descriptive and comparative anatomical studies were carried out. We analyzed 200 CT studies of Mexican patients of known age and gender. The images were analyzed using specialized software for reformatting that could determine cortical and endosteal diameters and cortical thickness at the level of the pedicle isthmus. The mean and standard deviation for each measurement parameter were determined, and a parametric correlation test was performed to compare the variations between the age groups of the same gender. Significant differences in the pedicle diameters between men and women were evident for most of the age groups (p <0.05). The cortical and endosteal pedicle width showed an increase from L1 to L5; the reverse was observed for cortical and endosteal pedicle height. No significant differences were evident with respect to age in the horizontal and vertical diameters for most of the generated study groups. The lateral cortical bone had the lowest scores of the study. The mean values of the morphometric characteristics of the pedicle isthmus obtained in this study will be helpful to conclusively define the pedicle dimensions and to improve the transpedicular approach to the lumbar spine

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Divergent dynamics and the Kauzmann temperature in glass forming systems.

In the last decade the challenging analysis of previtreous behavior of relaxation time (τ(T)) in ultraviscous low molecular weight liquids led to the conceptual shift of the glass transition physics toward theories not predicting a "finite-temperature" divergence. This "breakthrough" experimental finding was strengthened by the discovery that "dynamic" (i.e. from τ(T) fitting) and "thermodynamic" estimations of the "ideal glass" (Kauzmann) temperature do not match, what in fact questioned its existence. In this report, due to the novel way of analysis based on the transformation of τ(T) experimental data to the activation energy temperature index form, the clear prevalence of the "finite-temperature" divergence is proved. The obtained "dynamic" singular temperatures clearly coincide with "thermodynamic" estimations of the Kauzmann temperature, thus solving also the second mystery. The comprehensive picture was obtained due to the analysis of 55 experimental data-sets, ranging from low molecular weight liquids and polymers to liquid crystal and plastic crystals.

Age- and gender-related variations in morphometric characteristics of thoracic spine pedicle: A study of 4,800 pedicles.

Transpedicular spinal fusion is the most commonly used fixation technique for the surgical treatment of vertebral disorders. However, the instrumentation of the thoracic spine using this technique continues to be controversial. The objective of the present study was to determine the morphometric characteristics of the thoracic pedicle and to establish how these characteristics vary with gender and age. Two hundred thoracic spines (4800 thoracic pedicles) from individuals of known gender and age were analyzed (in accordance with the order of vertebrae). The spines were divided into six groups according to age and gender. The horizontal and vertical diameters of the thoracic pedicle were determined for each piece. The mean and standard deviation of each variable were determined, and differences between age groups for each gender were evaluated using parametric correlation tests. The pedicle diameters of men and women differed significantly for most groups (P < 0.05). The horizontal diameters decreased from T1 to T5 and increased up to T12. The vertical diameter followed a cephalocaudal pattern of development from T1-T12. The pedicle diameters decreased with increasing age in women, while the opposite trend was observed in men. In men, the dimensions of the thoracic spine pedicle increase with increasing age; in women, they decrease. These differences should be taken into account when selecting the appropriate pedicle screw.

A universal description of ultraslow glass dynamics.

The dynamics of glass is of importance in materials science but its nature has not yet been fully understood. Here we report that a verification of the temperature dependencies of the primary relaxation time or viscosity in the ultraslowing/ultraviscous domain of glass-forming systems can be carried out via the analysis of the inverse of the Dyre-Olsen temperature index. The subsequent analysis of experimental data indicates the possibility of the self-consistent description of glass-forming low-molecular-weight liquids, polymers, liquid crystals, orientationally disordered crystals and Ising spin-glass-like systems, as well as the prevalence of equations associated with the 'finite temperature divergence'. All these lead to a new formula for the configurational entropy in glass-forming systems. Furthermore, a link to the dominated local symmetry for a given glass former is identified here. Results obtained show a new relationship between the glass transition and critical phenomena.

The new insight into dynamic crossover in glass forming liquids from the apparent enthalpy analysis.

One of the most intriguing phenomena in glass forming systems is the dynamic crossover (T(B)), occurring well above the glass temperature (T(g)). So far, it was estimated mainly from the linearized derivative analysis of the primary relaxation time τ(T) or viscosity η(T) experimental data, originally proposed by Stickel et al. [J. Chem. Phys. 104, 2043 (1996); J. Chem. Phys. 107, 1086 (1997)]. However, this formal procedure is based on the general validity of the Vogel-Fulcher-Tammann equation, which has been strongly questioned recently [T. Hecksher et al. Nature Phys. 4, 737 (2008); P. Lunkenheimer et al. Phys. Rev. E 81, 051504 (2010); J. C. Martinez-Garcia et al. J. Chem. Phys. 134, 024512 (2011)]. We present a qualitatively new way to identify the dynamic crossover based on the apparent enthalpy space (H(a)(') = dlnτ/d(1/T)) analysis via a new plot lnH(a)(') vs. 1∕T supported by the Savitzky-Golay filtering procedure for getting an insight into the noise-distorted high order derivatives. It is shown that depending on the ratio between the "virtual" fragility in the high temperature dynamic domain (m(high)) and the "real" fragility at T(g) (the low temperature dynamic domain, m = m(low)) glass formers can be splitted into two groups related to f < 1 and f > 1, (f = m(high)∕m(low)). The link of this phenomenon to the ratio between the apparent enthalpy and activation energy as well as the behavior of the configurational entropy is indicated.

Organomegaly and tumors in transgenic mice with targeted expression of HpaII methyltransferase in smooth muscle cells.

Current data suggest that angiogenesis, smooth muscle cell migration, differentiation and proliferation may be epigenetically regulated. Prokaryotic DNA methyltransferases have been proposed as tools to modify mammalian DNA methylation. In order to assess the impact of DNA hypermethylation on smooth muscle pathophysiology, we expressed an HpaII site-specific methyltransferase transgene in smooth muscle cells in mice. The enzyme is expected to target only a subset (CCGG) of unmethylated CpG dinucleotides, thus avoiding possible deleterious effects of widespread hypermethylation. Transgenics of two independent lines were born at expected frequencies, showed no obvious abnormalities and were fertile. Nevertheless, ~30% of > 1 year-old transgenics developed organomegaly and ~20% showed a range of tumors. Global DNA methylation was unchanged in transgenic tissue whether hyperplastic or normal, but tumor DNA showed a pronounced global hypermethylation. DNA hypermethylation was not indiscriminate, as five tested tumor suppressor genes showed promoter CpG and non-CpG hypermethylation and transcriptional down-regulation, whereas the methylation status of one intergenic CpG islands, repeated elements (n=2) and non-tumor suppressor gene promoters (n=3) was unchanged. Our work is the first report on the effects of HpaII methyltransferase on endogenous chromatin and in a whole animal. Furthermore, our data expand previous findings that imply that global DNA hypomethylation is not an obligate oncogenic pathway at least in the tumor types examined here.

A general approach for determining the diffraction contrast factor of straight-line dislocations.

Dislocations alter perfect crystalline order and produce anisotropic broadening of the X-ray diffraction profiles, which is described by the dislocation contrast factor. Owing to the lack of suitable mathematical tools to deal with dislocations in crystals of any symmetry, contrast factors are so far only known for a few slip systems in high-symmetry phases and little detail is given in the literature on the calculation procedure. In the present paper a general approach is presented for the calculation of contrast factors for any dislocation configuration and any lattice symmetry. The new procedure is illustrated with practical examples of hexagonal metals and some low-symmetry mineral phases.

[Effect of hyaluronic acid on ureteropyelic anastomosis healing. Experimental study]. / Efecto del ácido hialurónico en la cicatrización de la anastomosis ureteropiélica. Estudio experimental.

BACKGROUND: Ureteropyelic obstruction is the most frequent congenital cause of obstructive uropathy in the newborn. Its repair is based on surgical procedures and has a very high rate of relapse of secondary stenosis to fibrosis (5-12%) in open repair and 10-20% in endo-urological pyeloplasties. Hyaluronic acid has demonstrated therapeutic utility in modulating the healing process and its effect in scar formation from ureteropyelic anastomosis is determined. METHODS: An experimental, controlled, comparative, double blind study was performed. Sample n = 20 per protocol with d = 26%, alpha = 0.05, beta = 0.80. Two groups of Wistar rats, 4 months of age and weighing between 250 and 350 g, were used. Under general anesthesia, Vision 12 x was used and bevel section was realized in the left ureteropyelic union and end-to-end anastomosis with Vicryl 7-0. Experimental group was treated with 25 microg of hyaluronic acid and group B was treated with placebo. The rats were reoperated on the 15th day and adherences in cavity were quantified. To quantify the degree of fibrosis, samples of ureteropyelic anastomosis tissue were dyed with Masson Trichrome and observed microscopically. Inferential statistics were used with a = 0.05. RESULTS: Macroscopic: there were adherences in 75 % of group A and 90 % of the group B (p >0.05). Microscopic: anastomotic fibrosis in group A (534 +/- 292 micro) was significantly lower (p = 0.043) than that of group B (728 +/- 295 micro). CONCLUSIONS: Hyaluronic acid plays a role in diminishing the formation of fibrosis from ureteropyelic anastomosis in an animal model.

On the algebra of binary codes representing close-packed stacking sequences.

A systematic use of binary codes derived from the Hagg symbol are used to study close-packed polytypes. Seitz operators acting over the corresponding binary codes are defined and used. The number of non-equivalent polytypes of a given length are calculated through the use of the Seitz operators. The same procedure is applied to the problem of counting the number of polytypes complying with a given symmetry group. All counting problems are reduced to an eigenvector problem in the binary code space. The symmetry of the binary codes leads to the different space groups to which polytypes can belong.