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Introduction: Aggressive fibromatosis, also known as desmoid tumour (DT), is a locally invasive soft tissue malignancy originating from fascial planes, connective tissue, and musculoaponeurotic structures of the muscles. The symptoms greatly depend on the location and size of the tumour. Case report: A 68-year-old male patient without any comorbidities with a large, palpable mass in the abdomen underwent computed tomography (CT) of the abdomen during diagnostic examination in September 2017 in another centre. The CT scan revealed a giant intraperitoneal 30×40cm tumour without signs of infiltrating the surrounding organs and large vessels. The tumour biopsy revealed an aggressive DT. The patient was scheduled for tumour resection. Midline laparotomy was performed in the supine position under general anaesthesia. After gaining access to the abdominal cavity, 8 litres of clear ascites were evacuated. The tumour was not attached to the abdominal wall. Large omentum was freed from the DT. The perioperative finding confirmed the CT images of DT encapsulation of the medial colic artery, part of the small intestine, and transverse colon. The tumour was resected with part of the mesenteric radix, 30 cm of small intestine, and 2/3 of the transverse colon. After the DT was removed entirely, the small intestine was re-anastomosed end to end. The abdominal cavity and the liver were carefully checked for bleeding. The abdominal cavity was closed in a standard manner. Results: The postoperative hospital stay was uneventful. The patient was discharged on the 7th postoperative day with prophylactic low weight molecular heparin for one month. Currently, we have five months of follow-up with no signs of DT recurrence based on CT examination. The histology of the resected tumour confirmed the diagnosis of a desmoid tumour (aggressive abdominal fibromatosis). Conclusion: Desmoid tumours are benign neoplasms with no metastatic potential. However, their treatment is challenging due to their aggressive growth, infiltrative behaviour, and a high tendency to recur

Supercritical water-cooled reactor candidate materials are typically corrosion-resistant alloys whose mass changes in supercritical water fluctuate around zero. A previous interlaboratory corrosion experiment exercise revealed large scatter in mass change results between laboratories. Here, we reduced systemic differences between laboratories by unilateral preparation of coupons and unilateral chemical cleaning. Type 310S stainless steel and Alloy 800HT test coupons were exposed for 1000 h to 550 °C, 25 MPa, deaerated water. Average mass loss for 310S and 800HT was 38 ± 26 and 51 ± 31 mg/dm2, respectively. Differences in mass transfer, galvanic and local corrosion, and average coupon temperature may explain the poor reproducibility.

The traditional method of corrosion studies of structural materials exposed to water at high pressures and temperatures is ex-situ weight gain/loss estimation and analyses of the oxide scales. In this work, in-situ electrochemical impedance spectroscopy (EIS) is applied to study behaviour of 316 L stainless steel exposed to sub-critical and super-critical water (SCW) with the aim to investigate the effect of temperature, in particular close to the critical point of water. As the second objective, the effect of exposure time during the long-term exposure at 500 °C was investigated. Impedance data were analyzed and discussed, based on changes in the physical and chemical properties of water. Instantaneous corrosion rate data, estimated from impedance data, were converted in weight differences and compared with the literature data available for 316 L steel corrosion in SCW. The good agreement obtained supports applicability of in-situ EIS for corrosion studies in super-critical range.

Aorto-iliac occlusive disease is best treated with endovascular angioplasty/stenting or surgical bypass, depending on disease severity. Aorto-iliac endarterectomy was frequently used until the 1980s. However, it can still be performed in cases of previous failure or contraindication of standard methods. The aim was a retrospective evaluation of a single-center case series of aorto-iliac endarterectomy.Seven patients at mean age 60±8 years (5768 years) were treated by aorto-iliac endarterectomy between 2013 and 2018. Rutherford categories of leg ischemia were 2 (moderate claudication) 3x, 3 (severe claudication) 2x, 4 (rest pain) and 5 (toe gangrene). The reasons for endarterectomy approach were: late in-stent iliac occlusion in an oncology patient, failure or complication of previous endovascular treatment of short iliac stenosis 2×, high infection risk of prosthesis use in long iliac-femoral occlusion, and short iliac occlusions 3x. Two patients after previous organ transplant were on immunosuppression.Technical success rate was 100%. There was no peri-operative (30 days) death or amputation. Mean follow-up was 17 months (1.1 month3.3 year). One patient required additional tibial bypass 1 month after endarterectomy to heal foot gangrene. One patient developed symptomatic re-stenosis which was treated with iliac stenting 8 months after procedure. All patients clinically improved and recovered from leg ischemia. Two patients died of tumor with preserved limb 1.1 month and 3.1 years after procedure, respectively. Five remaining patients are asymptomatic with patent revascularization to date.Aorto-iliac endarterectomy is a vital alternative technique for revascularization in selected patients when other methods seem inappropriate. Key words: endarterectomy - peripheral arterial disease - iliac artery - abdominal aorta.

Oxidační kinetiku lze v případě koroze zirkoniových slitin rozdělit do dvou stádií, která jsou od sebe oddělená transientním stavem. Výskyt transientního stavu je z korozního hlediska klíčový, neboť při něm dochází ke zvýšení rychlosti oxidace. V této práci byly pomocí in-situ elektrochemické impedanční spektroskopie studovány slitiny zirkonia Zr–Nb a Zr–Sn při teplotě 340 °C a tlaku 15 MPa v prostředí, které simulovalo chladivo reaktoru VVER. Cílem dlouhodobých experimentů (až 9000 h) bylo charakterizovat oxidační kinetiku v závislosti na expoziční době a typu zirkoniové slitiny. Výsledky ukázaly, že za uvedených experimentálních podmínek dochází u slitiny zirkonia Zr–Sn k dřívějšímu dosažení přechodu, tzv. transientnímu stavu.

Fulfilling the goals of space-based exoplanetary transit surveys, like Kepler and TESS, is impossible without ground-based spectroscopic follow-up. In particular, the first-step vetting of candidates could easily necessitate several hundreds of hours of telescope time -- an area where 2-m class telescopes can play a crucial role. Here, we describe the results from the science verification of the Ond\v{r}ejov Echelle Spectrograph (OES) installed on the 2-m Perek telescope. We discuss the performance of the instrument as well as its suitability for the study of exoplanetary candidates from space-based transit surveys. In spite of being located at an average European observing site, and originally being conceived for the study of variable stars, OES can prove to be an important instrument for the exoplanetary community in the TESS and PLATO era -- reaching accuracies of a few tens of m/s with reasonable sampling and signal-to-noise for sources down to V$\sim$13. The stability of OES is demonstrated via long-term monitoring of the standard star HD~109358, while its validity for exoplanetary candidate verification is shown using three K2 candidates EPIC~210925707, EPIC~206135267 and EPIC~211993818, to reveal that they are false positive detections., Comment: accepted for publication in PASP

Properties of Portland cement mixtures with various fractions of metakaolin were studied. 10% of Portland cement CEM I 42.5 R was replaced by different fractions of high reactivity metakaolin with defined chemical and mineralogical properties. Various fractions of metakaolin were prepared by jet mill classifying system. There is a clear trend between fineness of metakaolin and hydration heat development. Due to metakaolin presence in mixtures the compressive strength development of mortars is rather slower for coarser fractions but 28-day flexural strengths are improved for all fractions of metakaoline used in mixtures compared to reference sample of pure Portland cement. Yield point, plastic viscosity and adhesion of fresh pastes are considerably influenced by fineness of metakaolin used in cement pastes., {"references":["J. A. Kostuch, G.V. Walters, T. R. Jones, \"High performance concretes\nincorporating metakaolin - a review,\" in: R. K. Dhir, M. R. Jones (Eds.),\nConcrete 2000, vol. 2, E&FN Spon, London, 1993, pp. 1799– 1811.","M. H. Zhang, V. M. Malhotra, Cem. Concr. Res., vol. 25, 1995, pp.\n1713-25.","Gruber, K.A., Sarkar, S.L. World Cem., vol. 2, 1996, pp. 78-80.","R. F. Feldman, Cem. Concr. Res., vol. 16, 1986, pp. 31.","S. Wild, J. Khatib, Cem. Concr. Res., vol. 28, No. 6, 1998, pp. 803–809.","A. Goldman, A. Bentur, Adv. Cem. Based Mater., vol. 1, 1994, pp. 209–\n215.","A. H. Asbridge, G. A. Chadbourn, C. L. Page, Cem. Concr. Res., vol.\n31, 2001, pp. 1567–1572.","J. M. Gaidis, E. M. Gartner, Hydration mechanisms, II in J. Skalny, S.\nMindess (eds.), Materials Science of Concrete, vol. 2, American\nCeramic Society, Westerville, OH, 1989, pp. 95-125.","N. Tenoutasse, Proceedings of the Fifth International Symposium on the\nChemistry of Cement, Volume II, The Cement association of Japan,\nTokyo, Japan, 1968, pp. 372-378.\n[10] J. W. Bullard, H. M. Jennings, R. A. Livingston, A. Nonat, G. W.\nScherer, J. S. Schweitzer, K. L. Scrivener, J. J. Thomas, Cem. Concr.\nRes., vol. 41, 2011, pp. 1208-1223.\n[11] E. Gallucci, P. Mathur, K.L. Scrivener, Cem. Concr. Res., vol. 40, 2010,\npp. 4-13.\n[12] S. Wild, J. Khatib, A. Jones, Cem. Concr. Res., vol. 26, 1996, pp. 1537-\n1544. [13] J. M. Justice, K. E. Kurtis, ASCE J. Mater. Civ. Eng., vol. 19 (9), 2007,\npp. 762 –771.\n[14] M. Frías, M. I. Sánchez de Rojas, J. Cabrera, Cem. Concr. Res., vol. 30,\n2000, pp. 209–216.\n[15] X. Qian, Z. Li, Cem. Concr. Res., vol. 31, 2001, pp. 1607–1611.\n[16] L. Courard, A. Darimont, M. Schouterden, F. Ferauche, X. Willem, R.\nDegeimbre, Cem. Concr. Res., vol. 33, 2003, pp. 1473–1479.\n[17] F. Cassagnabère, P. Diederich, M. Mouret, G. Escadeillas, M. Lachemi,\n\"Impact of metakaolin characteristics on the rheological properties of\nmortar in the fresh state,\" Cem. Concr. Comp., vol. 37, 2013, 95-107."]}

The paper presents the results of water quality monitoring of road and parking surface run-off, which was done in the city of Brno in 2008-2009 and 2013-2014. The main results of the effectiveness of retention and infiltration facility treatment for PAH, petroleum substances, chlorides and selected heavy metals are presented, too. The system of facilities was built for a parking place located in Brno-Bohunice (Masaryk University campus). A retention basin was built near a shopping centre in Brno. The results of analyses and field measurements allow for comparing the evolution and changes of the filtration media characteristics, treatment effectiveness and changes in pollution. The aim of the evaluation is to provide information for the proper maintenance of retention, infiltration and treatment facilities for the surface run-off source of pollution of water bodies. Příspěvek prezentuje výsledky sledování jakosti vod z povrchový odtoků silnic a parkovacích ploch, který se prováděl v Brně v letech 2008-2009 a 2013-2014. Mezi hlavní výsledky účinnosti retenční a infiltrační zařízení patří sledované ropné látky, chloridy a vybrané těžké kovy. Pozorovací zařízení bylo postaveno na parkovací ploše se nachází v Brně-Bohunicích (univerzitní kampus Masarykovy univerzity). Retenční nádrž byla postavena v blízkosti nákupního centra v Brně. Výsledky analýz a měření v terénu umožňují srovnání vývoje a změn charakteristik filtračních materiálů, účinnosti zařízení a změny znečištění. Cílem hodnocení je poskytnout informace pro správnou údržbu retenčních, infiltračních a čistících zařízení pro povrchové odtoky do vodních útvarů.

Calcofluor-allied optical brightener Rylux BSU stimulated spore germination rate in Trichophyton mentagrophytes and Aspergillus fumigatus both if supplemented into Sabouraud glucose agar and if used for pretreatment of spore suspension prior to inoculation at low concentrations. Maximum stimulation of germination was obtained if 0.2% Rylux BSU was used for pretreatment in aqueous solution for 1 d prior to inoculation (130% in T. mentagrophytes and 150% in A. fumigatus, respectively). Pretreatment with 1% Rylux BSU provided strong protection against UV-irradiation and resulted in increased yields of cultural variants after UV-irradiation.

Cryptococcus neoformans was grown in 96-well microtiter plates sealed by foil which is less than 0.01 % permeable to oxygen. On day 14 of the cultivation, we observed peculiar clusters of small droplike daughter cells arranged aroundor = 4 % of mother cells. The fact that most of the other cells had died indicates that few cells had been able to survive hypoxic conditions and escape the cell-cycle arrest. However, their daughters were unable to separate from them and to continue their proliferation under such conditions.

Rylux BSU and congo red bind to chitin, interfere with proper cell-wall assembly, and stimulate chitin synthesis by increasing, most probably, chitin synthase 3 (ChS3) levels in Saccharomyces cerevisiae. On the other hand, the antibiotic nikkomycin Z inhibits chitin synthesis competitively. As ChS3 is the critical target of nikkomycin Z, its effect was tested in cells inhibited in growth by Rylux BSU or Congo red. Nikkomycin Z counteracted this inhibition but did not counteract aberrant cell-wall formation. These results indicate that chitin synthesis stimulation is the key step in Rylux BSU and congo red inhibition and support the idea that increase in chitin synthesis represents a compensatory response to damaged cell-wall structure. As Rylux BSU and congo red bind to newly synthesized chitin, further damage is caused in the wall and the response works in this case contrariwise. Nikkomycin Z breaks this vicious circle by counteracting the chitin synthesis stimulation.

A single crystal of antimony telluride, grown from elements of semiconductor purity by means of the Bridgman method, is characterised by the departure from stoichiometry as determined from energy dispersive X-ray spectroscopy, by the concentration of free charge carriers p as obtained from the interpretation of the reflectivity spectra in the plasma resonance frequency range, by its density d, and by lattice parameters a and c. The investigated crystal of stoichiometry Sb 2 Te 2.948 has the following values: p = 6.714 x 10 19 cm -3 , d = (6.50 ± 0.01) g cm -3 , a = 0.42643(5) nm, c = 3.0427(4) nm. The departure from stoichiometry is explained using a model taking into account the existence of antisite Sb' Te defects as well as tellurium and antimony vacancies in the crystal lattice: this model in connection with the experimental data allows us to calculate the concentration of Sb' Te defects and to determine their formation energy E AS = (0.32 ± 0.01) eV.

Elemental Bi, Te, and Ge of 5N purity were used to prepare Bi2Te3(GeTe) single crystals with germanium content varying from 0 up to 2.3 × 1021 cm−3. The samples were characterized by reflectivity measurements in the plasma resonance frequency range and by measurements of the electrical conductivity. Germanium content in the samples was determined by means of energy dispersive analysis. The reflectivity spectra were interpreted on the basis of the Drude-Zener theory in the aim to obtain information on the concentration of the free carriers in the samples. It was found that Ge atoms in the Be2Te3 crystal lattice behave as acceptors. A comparison of the hole concentration with the amount of germanium built into the crystal lattice revealed that only about 1/100 of the total number of Ge atoms act as acceptors. This effect is explained by two different ways of incorporation of Ge atoms into the Bi2Te3 lattice, viz: the formation of substitutional Ge'Bi defects acting as acceptors and the formation of seven-layer-lamellae of the TeBiTeGeTeBiTe composition, which corresponds to the structure of GeBi2Te4. Aus den Elementen Bi, Te, Ge des Reinheitsgrades 5N wurden die Einkristalle Bi2Te3(GeTe) mit verschiedener Ge-Konzentration (0–2.3 × 1021 Ge-Atome cm−3) gezuchtet. Die elektrische Leitfahigkeit und das Reflexionsvermogen im IR Bereich wurden gemessen. Der Ge-Gehalt in praparierten Kristallen wurde mit Hilfe des energ dispersiven Analysators bestimmt. Durch die Interpretation der Reflexionsmessungen wurden Auskunfte uber die Konzentrationsanderungen der freien Ladungstrager erhalten. Diese Ergebnisse fuhren zum Schlus, das ein Teil (etwa 1/100) der eingebauten Ge-Atome das Bi-Untergitter besetzt und Anlas gibt zu den negativ geladenen Substitutionsdefekten Ge'Bi. Wahrend der andere Teil ungeladene Defekte bildet. Die Bildung ungeladener Defekte durch den Einbau von Ge-Atomen in das Be2Te3-Kristallgitter wird in folgender Weise erklart: Ge-Atome bilden Sieben-Schicht Anordnungen der Zusammensetzung TeBiTeGeTeBiTe die der Struktur der Verbindung GeBi2Te4 entsprechen. Diese Sieben-Schicht Anordnungen sind ungeladen, die eingebauten Ge-Atome in diesen Schichten sind also elektrisch inaktiv.

An unusual case of implant failure after revision total knee arthroplasty (TKA) is presented and the case report is completed with the results of an ensuing biomechanical study made to explain possible causes leading to a fracture of the tibial stem. For this we used electron microscopic and biomechanical analyses. There was no material defect found at the site of fracture. By computerized modelling of the clinical situation, however, we found out that asymmetrical progressive osteolysis of the proximal tibia could have caused significant changes in mechanical straining associated with qualitative alterations in the process of degradation and erosion of the implant, eventually leading to a fracture of the tibial stem. In this way mechanical straining at the site of fracture could have exceeded the failure threshold of titanium alloy. Stem fracture of a current tibial component design has not yet been described in the literature. The only failure so far reported concerns the stem of a femoral component, and this has also been explained by biomechanical reasons. It follows from this study that patients with progressive osteolysis around the TKA should be followed up more frequently. The conclusions of this biomechanical analysis emphasize the importance of a thorough reconstruction of bone defects in order to improve long-term survival of the implant. Key words: revision, total knee arthroplasty, osteolysis, failure, fracture, tibial stem.

Single crystals of Bi2-xInxSe3 (x = 0.0-0.66) were prepared from the elements of 5N purity using the modified Bridgman method. On the samples with a various content of incorporated In-atoms the reflectivity in IR-region and the transport coefficients (electrical conductivity σ⊥, Hall coefficient RH (B ∥ c), Seebeck coefficient S⊥) were measured. The results showed that the In-atoms incorporation to the crystal lattice of Bi2Se3 in the region of small concentrations of In-atoms increases the free carriers concentration, in the region of higher concentrations of In-atoms the free carriers concentration is suppressed. On the ground of measured changes in the values of transport coefficients and optical parameters (determined from the interpretation of infrared reflectivity) a model of point defects in the Bi2-x Inx Se3 crystal lattice has been suggested. This model takes into account the existence of antisite defects Bi'Se in the Bi2Se3 crystal lattice the concentration of which is suppressed by incorporated In-atoms. The built-in In-atoms form uncharged defects InxBi which are positively polarized.

The endometrium acquires the ability to implant a hatched blastocyst only within a specific time termed the receptive phase. Ovarian steroid hormones are essential for structural and functional changes that prepare the endometrium to be receptive. Pinopodes have been suggested to be markers of uterine receptivity. The aim of this study was to compare the pinopode expression and serum levels of ovarian steroid hormones in the mid-luteal phase of the natural cycle and in a "mock" cycle in the same subject. Sequentional endometrial biopsies within 48 hours were obtained from women in the mid-luteal phase (ovulation +5, ovulation +7) of the natural cycle and in the "mock" cycle (progesterone supplementation +5 and +7). Biopsies were examined under a scanning electron microscope for pinopode detection. The expression of pinopodes was similar in both cycles, where pinopodes covered about 5 % of the endometrial surface. The developmental stages were also similar with a slight increase of fully developed pinopodes in both samples in the "mock" cycles. Our findings suggest that hormonal preparation of the endometrium do not change the timing of pinopode expression.

The polyethylene liner has appeared to be a weak point in total hip arthroplasty. An early wear-through or a fracture of the polyethylene liner have been referred to as a catastrophic failure. The aim of the present study is to report our experience with this rare complication in ABG I hip prostheses.Between September 1994 and January 2000 a total of 506 ABG I prostheses were implanted at our clinic. Due to wear-related complications, revision arthroplasty had to be performed in 90 hips in 23 male and 63 female patients by January 2002. Extensive titanium metallosis associated with polyethylene failure was found in 11 hips of 11 female patients. The remaining 56 hips of 52 female patients served as a control group.The characteristics recorded in every patient's included age, type of patient, sex, height, weight, ESR, CRP, diagnosis, Harris hip score before revision, cup size, abduction angle of the cup, time between the primary and revision surgery and implant stability. Student's t-test, the Mann-Whitney U-test and Pearson's chi 2 test were used to evaluate the results.The complete failure of ABG I prostheses occurred in 2.17% of the replaced hips (11/506). A fracture or complete wear-through were the causes of failure in three (3/11, 27%) and eight (8/11, 73%) hips, respectively. The average cup size in hips without metallosis was 48.9 mm (range, 44-58; SD, 3.1) and that in hips with metallosis was 46.5 mm (range, 46-48; SD, 0.9). This difference was highly significant (t-test, p = 0.00002; U-test, p = 0.014). In the hips with metallosis, the average thickness of the polyethylene liner was 5.17 mm (range, 4.9-5.9; SD, 0.45) and the Harris hip scores before revision were significantly lower than in the hips without metallosis (59 versus 70.3 points; t-test, p = 0.023; U-test, p = 0.044). There were no other significant differences between the hips with early catastrophic failure of the polyethylene liner and those without it.Several studies have shown an indirect relationship between polyethylene thickness and its wear. Berry et al. reported catastrophic failure in hip prostheses with a polyethylene thickness of less than 5 mm; in our study, the three failed polyethylene liners were 5.9 mm in thickness.This is the first report on a wear-through of the polyethylene liner in ABG I cups. It is suggested that a thin polyethylene liner, design characteristics and probably also poor polyethylene quality are crucial factors responsible for rapid wear in ABG I cup. The highest risk is associated with the combination of a 46 mm cup and a 28 mm head. Patients who have prostheses of this size should be checked up more frequently.

Ultrastructure of the superficial relief of the endometrial epithelium was investigated under the scanning (SEM) and transmission electron microscopes (TEM) in a group of patients after the hormonal stimulation, performed in the program of in vitro fertilization and embryotransfer. The results were compared with those obtained in a group of patients studied during the secretory phase of normal menstrual cycle. Total 26 bioptic samples were subjected to the investigation, 13 in each group. Different types of the epithelial surface were classified in TEM and SEM and their relative amount was evaluated quantitatively in TEM. Special attention was paid to the pinopodes, considered as specific markers of the nidation window. Differences in the number of pinopodes were observed under the SEM in two groups of patients after different schemes of the hormonal treatment. These differences were not manifested under the TEM due to the small frequency of pinopodes in the ultrathin sections. The ultrastructural changes observed in the two groups of patients after different schemes of hormonal stimulation can be considered as signs of the changed metabolic activity of the endometrial epithelium and they can reflect the different endometrial receptivity for nidation.

The ultrastructure of NCS was investigated in two groups of patients (15 in each) during the secretory phase of the normal menstrual cycle and after the hormonal stimulation performed in the IVF programme by GnRH-a, FSH and hCG. Three developmental stages of the NCS were classified. The most numerous were the NCS in the mature stage (type 2), less in the early developmental stage (type 1) and least in the regression stage (type 3). The simultaneous occurrence of all three types does not conform the statement of Spornitz. The proportions of the three types were identical in both investigated groups of patients. The number of NCS (per 100 of nuclei) was higher in the group after hormonal stimulation than in the normal cycle. The quantitative measurement of the NCS showed its larger size in the group after hormonal stimulation than in the normal cycle, but the differences in the shape were not significant. In the serial ultrathin sections we demonstrated the relation of NCS to the nucleolus and to the invaginations of the nuclear envelope, the formation of the electron lucent center and the spiral arrangement of the tubules. In the early regression stage we described the relation of the internal row of tubules to the formed myelin figures. We suppose that the higher number and larger size of NCS can be taken as a sign of the increased activity of the endometrium during the early secretory phase after the hormonal stimulation.

In the submitted case-history the authors describe a hitherto unknown proarrhythmic effect of adenosine. Adenosine was administered on account of supraventricular tachycardia and the undesirable proarrhythmic effect was so-called "sine wave-like tachycardia" and ventricular fibrillation. Proarrhythmia was resistant to electric cardioversion and resuscitation was successful probably only after the breakdown of adenosine. The very short half-life of breakdown of this antiarrhythmic is thus useful not only for antiarrhythmic strategy but, because of the possible occurrence of rare proarrhythmias, adenosine holds a preferential position among other antiarrhythmic drugs.

The aim of this letter is to report the preparation of Sb2Te3-Sb2Teg_xSx and Sb2Te3-Sb2Te3_xS~ monocrystalline structures. Contrary to all expectations, p -n junctions 'were observed on these structures. Similar problems were discussed previously [1] for Bi2Te3-Bi2Se3 system. Samples with a concentration gradient of Se and S, respectively, were prepared from Sb2Te3 single crystals. Sb2Te3 single crystals were grown using the Bridgman method in conical quartz ampoules. The starting elements of semiconductor purity (99.999%) in the stoichiometric ratio were synthesized at a temperature of 1073 K for 48 h. Ampoules charged with synthesized polycrystalline material were lowered into t]~e temperature gradient of 400 K (5 cm) -I at a rate of 1.3 mmh -t. Single crystals obtained, approximately 60 mm long and 10 mm in diameter, were used to prepare the samples of dimensions 10 mm x 10 mm x 2 ram. The cleavage planes of single crystals formed the larger-area sides of the samples. The samples prepared in this way were annealed in S and Se vapour, respectively, at 623 K for 50 h. After annealing, the samples were cleaved into halves along the {0 0 0 1) planes. The resultant samples in plate-like form were of dimensions 10 m m x 10 m m x 1 mm, having higher concentration of S and Se, respectively, in one side of the sample. The concentration profiles of the samples were measured perpendicularly to the {0 0 0 1 ) planes by means of an energy-dispersive X-ray (EDX) microanalyser (KEVEX; Fig. 1). It follows from Fig. 1 that Se atoms diffuse into Sb2Te3 crystals relatively easily and form there an area of mixed crystal. This is in agreement with the phase diagram of the Sb2Teg-Sb2Se3 system [2]. The Sb atoms needed for the formation of a compound is probably taken from SbTe point defects. Therefore, the crystal volume increases. The process can be expressed by the equation

Mesure des coefficients de reflexion et de transmission dans le domaine infrarouge. Determination de la frequence de resonance du plasma, du temps de relaxation optique, de la constante dielectrique a hautes frequences du coefficient d'absorption K, et de la bande interdite. Influence de la composition

Sb 2 Te 3− x Se x ( x = 0.00−1.25) single crystals were prepared using a modified Bridgman technique. The homogeneity of the crystals grown in this way was checked by means of an energy dispersion analyser and by reflectivity measurements. X-ray structure analysis revealed that the lattice parameters a and c decrease with increasing selenium content in the crystals. The crystals were characterized by measuring the infrared reflectivity spectra, electric conductivity and Hall constant. Experimental results showed that the incorporation of Se atoms into the crystal lattice of Sb 2 Te 3 results in a suppression of the concentration of free carriers (holes).

Reflectance and transmittance in the IR spectral range are investigated on Sb2−xInxTe3 (x = 0.00 to 0.37) single crystal samples grown by a modified Bridgman method. By fitting the reflectance spectra the values of the plasma resonance frequency ωp, optical relaxation time τ, and high-frequency dielectric constant e∞are determined. With increasing indium concentration in the samples these quantities decrease from the values ωp = 1.88 × 1014 s−1, τ = 2.4 × 10−14 s, and e∞ = 55 for x = 0.00 down to the values ωp = 0.81 × 1014 s−1, τ = 0.8 × 10−14 s, and e∞ = 41 for x = 0.37. The observed variations are qualitatively accounted for by interaction of substitutional In defects arising on building of In atoms into the Sb2Te3 lattice with anti-site Sb defects. The transmittance curves permit to determine the dependence of the absorption coefficient x on incident photon energy. The change in the width of the optical gap with increasing In concentration in the samples is discussed. The values of the exponent α in the relation x ∼ λα for the long-wavelength absorption edge drop from 2.5 for Sb2Te3 to 1.2 for Sb1.63In0.37Te3. An den Proben von 2−xInxTe3-Einkristallen (x = 0,00 bis 0,37), dargestellt nach der modifizierten Bridgman-Methode, werden Reflektivitat und Transmission im IR-Bereich ermittelt. Durch das Anpassen der Reflexionsspektren werden die Werte der Plasma-Resonanzfrequenz ωp, der optischen Relaxationszeit τ und der Hochfrequenz-Dielektrizitatskonstante e∞ bestimmt. Mit zunehmender Indium-Konzentration sinken in den Proben die angegebenen Grosen von ωp = 1,88 × 1014 s−1, τ = 2.4 × 10−14 s und e∞ = 55 fur x = 0,00 zu Werten ωp = 0,81 × 1014 s−1, τ = 0,8 × 10−14 s und e∞ = 41 fur x = 0,37. Die beobachteten Veranderungen werden qualitativ durch Wechselwirkung der im Sb2Te3-Gitter entstehenden Substitutionsstorstellen In, mit Antistrukturdefekten Sb erklart. Aus dem Verlauf der Transmission wird die Abhangigkeit des Absorptionskoeffizienten x von der Energie einfallender Photonen ermittelt. Die Veranderung der optischen Breite der Bandlucke mit zunehmender In-Konzentration in den Proben wird diskutiert. Die ermittelten Werte des Exponenten α aus der Relation x ∼ δα fur die langwellige Absorptionskante sinken von 2,5 fur Sb2Te3 zu 1,2 fur Sb1.63In0.37Te3.

With the objective of analysing the relations between the concentration of free carriers in Bi2(Se1−xSx)3 ternary crystals and the vapour pressures of selenium and/or sulphur, a model describing the equilibrium between the vapour and the solid phase of a ternary crystal has been worked out by adopting the simplification that the ternary system can be taken for an ideal solid solution where the activity of Bi2S3 is equal to its concentration. Such an approach makes possible the determination of the equilibrium pressures of selenium and sulphur at various x values. Using pairs of these values, we calculated the equilibrium constant for the reaction V′ A +y 2 S 2 (g)+(l−y) 2 Se 2 (g) + e′0 at a temperature of 700 K. The proposed model explains well the experimentally observed variation of the concentration of free carriers in Bi2(Se1−xSx)3 crystals with increasing value of x (x = 0.00−0.16) under identical growth conditions.

Single crystals of Bi 2 Se 3− x S x (x = 0−0.45) were prepared by the modified Bridgman method. The homogeneity of the crystals was proved by X-ray fluorescence analysis and measurement of reflectivity spectra. Measurement of the crystal lattice parameters by the powder X-ray diffraction method showed that with increasing sulfur content the value of the lattice parameter c increases and a decreases. From the measurement of reflectivity in IR region, the electrical conductivity and the Hall coefficient, some basic physical parameters of Bi 2 Se 3− x S x crystals were obtained which characterize the crystals as semiconductors.

Sb2Te3−xSex(x=0·00−1·25) single crystals were prepared from 5N purity elements using a modified Bridgman method. Measurements of the reflectivity spectra in the plasma resonance frequency range, Hall constantRH(B∥c) and electrical conductivityσ⊥C were carried out on these samples at room temperature. With increasing selenium content a shift of the reflectivity minimum towards longer wavelengths was observed as well as an increase of the Hall constant and a decrease of the electrical conductivity — the incorporation of Se atoms into the Sb2Te3 crystal lattice results obviously in a decrease in the concentration of free carriers. This effect is accounted for by a change in the polarity of bonds in the Sb2Te3 crystal lattice, due to the formation of SeTex substitutional defects.

Transport parameters and optical properties of Bi 2 Te 3− x S x single-crystals with x=0–0.18 were studied. With increasing sulphur content the concentration of free current carriers decreases up to x =0.12, due to the interaction of S x Te defects with antisite defects Bi ′ Te , and then the p -type conductivity changes to the n -type. The optical gap of Bi 2 Te 3− x S x crystals increases with increasing S content. The obtained results led to the preparation of Bi 2 Te 3 -Bi 2 Te 3− x S x p – n junction by the heat treatment of p -type Bi 2 Te 3 in S vapours.

Concentrations of air pollutants measured by passive samplers, atmospheric deposition to forest ecosystems, soil water chemistry, nutrient content in the soil and foliage were all measured within a study of the causes of forest decline in Nýdek Forest Range, Jablunkov Forest District (Silesian Beskids). Declining Norway spruce stands are situated in a region of historically high air pollution load, mainly from the Třinec and Ostrava agglomeration. Air pollution significantly decreased in the second half of the 1990s. Forest soils showing the insufficiency of main nutrients remain today as the main factor affecting the forest vitality. The situation in the soil is subsequently reflected in the nutrition level of the assimilation tissues. Simultaneous effects of other stressors (e.g. biotic, meteorological ones) can support a sudden worsening of the stand health and cause serious damage.

AbstR ACt: In the second half of 20 th century silver fir regeneration has been observed throughout all of the Europe, including the Czech Republic. The Bohemian Forest – Sumava Mts. is one of the regions where the silver fir percentage in forest stands is supposed to be increased from the present 2% to nearly 12%. During the period 2006–2007, in the Czech part of the Bohemian Forest, samples of silver fir were taken mainly in the upper alti tudinal limit of silver fir occurrence. In the present paper the results of performed analyses are compared with similar surveys conducted in the other European regions. Samples from the Bohemian Forest, in contrast to other results, differ in higher phosphorus content and lower contents of calcium and manganese. Nitrogen content is slightly higher. Our values for the other elements (magnesium, potassium, zinc, sulphur) are comparable to those reported in Poland and Slovakia. In Germany, aside from the above mentioned differences, higher magnesium content was also found within the locality sampled.