Crystallographic orientation inhomogeneity and crystal splitting in biogenic calcite

The calcitic prismatic units forming the outer shell of the bivalve Pinctada margaritifera have been analysed using scanning electron microscopy–electron back-scatter diffraction, transmission electron microscopy and atomic force microscopy. In the initial stages of growth, the individual prismatic units are single crystals. Their crystalline orientation is not consistent but rather changes gradually during growth. The gradients in crystallographic orientation occur mainly in a direction parallel to the long axis of the prism, i.e. perpendicular to the shell surface and do not show preferential tilting along any of the calcite lattice axes. At a certain growth stage, gradients begin to spread and diverge, implying that the prismatic units split into several crystalline domains. In this way, a branched crystal, in which the ends of the branches are independent crystalline domains, is formed. At the nanometre scale, the material is composed of slightly misoriented domains, which are separated by planes approximately perpendicular to the c-axis. Orientational gradients and splitting processes are described in biocrystals for the first time and are undoubtedly related to the high content of intracrystalline organic molecules, although the way in which these act to induce the observed crystalline patterns is a matter of future research

Promoter methylation of cancer-related genes in gastric carcinoma

Genetic changes associated with gastric cancer are not completely known, but epigenetic mechanisms involved in this disease seem to play an important role in its pathophysiology. One of these mechanisms, an aberrant methylation in the promoter regions of genes involved in cancer induction and promotion, may be of particular importance in gastric cancer. Aim: To analyze the methylation status of eight genes: Apaf-1, Casp8, CDH1, MDR1, GSTP1, BRCA1, hMLH1, Fas in gastric cancer patients. Methods: The methylation pattern of the genes was assessed by methylation specific restriction enzyme PCR (MSRE-PCR) in gastric tumors taken during surgery of 27 patients and compared with the methylation pattern in material obtained from biopsy in 25 individuals without cancer and pre-cancerous lesions. Results: We observed a promoter hypermethylation in the Casp8, hMLH1, CDH1 and MDR1 in gastric cancer patients as compared with the controls. Additionally, we investigated the relationship between promoter hypermethylation and age, gender, smoking and gastric cancer family history. The hypermethylation of the hMLH1 gene occurred more frequently in female than in men, and the hypermethylation of the CDH1 gene was observed preferentially in smoking than in non-smoking individuals. Conclusion: The data obtained indicate that changes in DNA methylation may contribute to gastric carcinogenesis.Генетические изменения, ассоциированные с опухолью желудка, изучены не в полной мере. В то же время эпигенетические механизмы скорее всего играют ключевую роль и лежат в основе возникновения этого заболевания. Один из таких механизмов– нарушенияметилирования промоторов генов, которые регулируют злокачественнуютрансформациюи прогрессирование опухолевого процесса, может быть особенно важным в развитии рака желудка. Цель: проанализировать статус метилирования промоторов восьми генов: Apaf-1, Casp8, CDH1, MDR1, GSTP1, BRCA1, hMLH1, Fas у больных раком желудка. Методы: метилирование промоторов генов изучали с помощьюспецифической к сайтамметилирования рестрикцией с ПЦР (MSRE-PCR) на хирургическомматериале (опухоли желудка) 27 пациентов. Вкачестве контроля использовали иопсийныйматериал, полученный от 25 больных, у которых не было выявлено рака или предраковых состояний. Результаты: отмечали гиперметилирование промоторов генов Casp8, hMLH1, CDH1 и MDR1 в опухолевой ткани желудка по сравнению с контрольными образцами. Кроме того, нами была прослежена взаимосвязь между гиперметилированием промоторов генов и возрастом, полом пациентов, курением и семейной историей заболевания раком желудка. Гиперметилирование гена hMLH1 выявляли чаще у женщин, чем у мужчин, а гиперметилирование гена CDH1 — в основном у курильщиков. Выводы: полученные данные свидетельствуют о том, что метилирование ДНК может играть важную роль при развитии рака желудка

Around a problem of Nicole Brillouët–Belluot

We determine nontrivial intervals I ⊂ (0,+∞), numbers α ∈ R and continuous bijections f : I → I such that f(x)f−1(x) = xα for every x ∈ I

Serum levels of IL-6 type cytokines and soluble IL-6 receptors in active B-cell chronic lymphocytic leukemia and in cladribine induced remission.

We have investigated the serum concentrations of interleukin-6 (IL-6) and two IL-6 family cytokines-oncostatin M (OSM) and leukemia inhibitory factor (LIF)-in 63 patients with B-cell chronic lymphocytic leukemia (B-CLL) and 17 healthy controls using the enzyme-linked immunosorbent assay (ELISA) method. Simultaneously, we measured the serum levels of the soluble forms of two subunits of the IL-6 receptor complex-ligand binding glycoprotein 80 (sIL-6R) and glycoprotein 130 (sgp130). The cytokines and receptors were evaluated in 25 untreated patients and 38 patients treated with cladribine (2-CdA), as well as in 17 healthy controls. We have correlated the serum levels of these proteins with Rai's clinical stage of the disease, the response to 2-CdA treatment and some hematological parameters. We have also evaluated the correlation of the IL-6 serum level with the concentration of OSM and IL-6 soluble receptors. IL-6 was measurable in 62/63 (98.4%), OSM in 20/25 (80%) of untreated and 14/38 (37.8%) of the treated patients. sIL-6R and sgp130 were detectable in all 63 patients and LIF in none of the CLL patients. IL-6 serum level in untreated patients was not significantly different as compared to its concentration in the control group (P>0.05). However, in the patients treated with 2-CdA the IL-6 level was significantly lower (P<0.02), and the lowest concentration was found in the patients with complete remission (CR; median 1.4pg/ml; P<0.02). The concentration of sIL-6R was significantly higher in untreated (median 61.8 ng/ml) and treated (median 50.1 ng/ml) CLL patients when compared to normal persons (median 41.2 ng/ml; P=0.04; P<0.001, respectively). There was no difference between the sIL-6R levels in the patients with CR and the healthy controls. In non-responders sIL-6R concentration was the highest and similar to its level in the untreated patients. OSM level was higher in the untreated patients (median 1.8pg/ml) than in the normal controls (median 0.0pg/ml; P<0.001) and in the CR patients (median 0.0pg/ml; P<0.03). The serum concentration of sgp130 was similar in the untreated (median 480 pg/ml) and treated (median 470 pg/ml) patients, as well as in the healthy persons (median 420 pg/ml; P>0.05). We have found significant positive correlation between the levels of sIL-6R and the lymphocytes count in CLL patients (p=0.423; P<0.001). In addition, sIL-6R and OSM serum concentrations correlated also with CLL Rai stage. In conclusion, the serum level of IL-6, OSM and sIL-6R, but not LIF and sgp130, are useful indicators of CLL activity

Off-axis electron holography of magnetic nanostructures: magnetic behavior of Mn rich nanoprecipitates in (Mn,Ga)As system

The Lorentz off-axis electron holography technique is applied to study the magnetic nature of Mn rich nanoprecipitates in (Mn,Ga)As system. The effectiveness of this technique is demonstrated in detection of the magnetic field even for small nanocrystals having an average size down to 20 nm.Comment: 11 pages, 3 figure

On a functional equation involving iterates and powers

We present a complete list of all continuous solutions f : (0,+∞)→(0,+∞) of the equation f 2(x) = γ [f (x)]αxβ, where α, β and γ > 0 are given real numbers

Anisotropic elasticity in confocal studies of colloidal crystals

We consider the theory of fluctuations of a colloidal solid observed in a confocal slice. For a cubic crystal we study the evolution of the projected elastic properties as a function of the anisotropy of the crystal using numerical methods based on the fast Fourier transform. In certain situations of high symmetry we find exact analytic results for the projected fluctuations.Comment: 6 pages, 7 figure

Experimental quantification of useful and parasitic absorption of light in plasmon-enhanced thin silicon films for solar cells application

A combination of photocurrent and photothermal spectroscopic techniques is applied to experimentally quantify the useful and parasitic absorption of light in thin hydrogenated microcrystalline silicon (μc-Si:H) films incorporating optimized metal nanoparticle arrays, located at the rear surface, for improved light trapping via resonant plasmonic scattering. The photothermal technique accounts for the total absorptance and the photocurrent signal accounts only for the photons absorbed in the μc-Si:H layer (useful absorptance); therefore, the method allows for independent quantification of the useful and parasitic absorptance of the plasmonic (or any other) light trapping structure. We demonstrate that with a 0.9 μm thick absorber layer the optical losses related to the plasmonic light trapping in the whole structure are insignificant below 730 nm, above which they increase rapidly with increasing illumination wavelength. An average useful absorption of 43% and an average parasitic absorption of 19% over 400-1100 nm wavelength range is measured for μc-Si:H films deposited on optimized self-assembled Ag nanoparticles coupled with a flat mirror (plasmonic back reflector). For this sample, we demonstrate a significant broadband enhancement of the useful absorption resulting in the achievement of 91% of the maximum theoretical Lambertian limit of absorption

DNA double strand breaks repair and apoptosis induction in peripheral blood lymphocytes of head and neck cancer patients

Aim: To evaluate the generation and repair of DNA double strand breaks (DSBs) as a critical factors that define the efficiency of radiation therapy of cancer patients. Methods: Peripheral blood lymphocytes obtained from 18 patients with head and neck squamous cell carcinoma (HNSCC) and 18 healthy donors were studied. The efficiency of DSBs repair after genotoxic treatment with hydrogen peroxide and γ-radiation were examined by neutral comet assay. MTT assay was used for cell viability analysis and Annexin V-FITC kit specific for kinase-3 was employed to determine apoptosis. Results: Lymphocytes from HNSCC patients were sensitive to genotoxic treatment and displayed impaired DSBs repair. Finally, as a consequence of this finding we have evidenced higher rate of apoptosis induction after γ-radiation treatment of lymphocytes from HNSCC patients than those from healthy controls. Conclusions: DSBs repair and increased apoptosis in cells of patients with head and neck cancer is relevant for efficient therapy of HNSCC

Stan Scheller: The Forerunner of Clinical Studies on Using Propolis for Poor and Chronic Nonhealing Wounds

For hundreds of years poor and chronic nonhealing wounds have constituted a serious problem to medicine. What is more, treating such wounds is an expensive let alone a long-lasting process. The following paper describes Professor Scheller's achievements in using propolis for poor and chronic non-healing wounds. The authors' intention was to present the results connected with the use of the ethanolic extract propolis, in the treatment of patients suffering from burns, venous crural ulceration, local sacral bone pressure ulcers, suppurative osteitis and arthritis, suppurative postoperative local wound complications, and infected traumatic wounds