125 research outputs found
Metric mean dimension of irregular sets for maps with shadowing
We study the metric mean dimension of -irregular set in
dynamical systems with the shadowing property. In particular we prove that for
dynamical systems with shadowing containing a chain recurrent class , the
values of topological entropy together with the values of lower and upper
metric mean dimension of the set
are bounded from below by the respective values for class
Nanostructured Porous High Surface Area Ceramics for Catalytic Applications
In the present work new methods were developed for preparation of novel nanosized and nanostructured ceramic materials. Ordered mesoporous silica SBA-15 was found to be useful as a hard template for the nanocasting of silicon carbide and allowed the preparation of high temperature stable mesoporous silicon carbide ceramics. Chemical vapor infiltration of SBA-15 with dimethyldichlorosilane at elevated temperatures yields SiC/SBA-15 nanocomposites. The subsequent HF treatment of those composites resulted in silica removal and preparation of mesoporous silicon carbide with surface areas between 410 and 830 m2g-1 and high mesopore volume (up to 0.9 cm3g-1). The pore size (between 3 and 7nm in diameter) and surface area of mesoporous silicon carbide were controlled by adjusting the infiltration conditions (time, atmosphere). The mesoporous silicon carbide prepared via this method showed high structural thermal stability at 1300 oC, exceeding that of the SBA-15 template. However, the ordering on the mesoscopic scale was low. Nevertheless, highly ordered mesoporous silicon carbide materials were obtained via polymer melt infiltration in SBA-15. The low molecular weight polycarbosilane used as a preceramic precursor was converted at 1300 oC to silicon carbide inside the SBA-15, and after subsequent silica removal by HF, a highly ordered mesoporous material was obtained. Ordered mesoporous silicon carbide prepared by the methods reported here, may be an interesting material as a support due to its high temperature stability, chemical inertness, high thermal conductivity and semiconductor properties. In contrast to the nanocasting approach, based on the complete pore filling, also a new in-situ procedure for the preparation of finely dispersed metal and metal oxide particles inside ordered mesoporous silica was developed. A swelling agent (toluene) was used to deliver a hydrophobic platinum precursor into the surfactant micelles before addition of silica source. Such an in-situ method resulted in very high platinum incorporation (80-100%), not achieved for any other in-situ preparation procedures. Additionally, the presence of platinum allowed to decrease the template removal temperatures. Moreover, the method was also extended to other metal or metal oxide/ordered mesoporous silica systems. This may be especially interesting for the preparation of ordered mesoporous materials with low melting points, where typically the structure collapses during the high temperature calcinations process. The in-situ synthesized V2O5/MCM-41 materials were used to prepare VN/MCM-41 composites via nitridation in ammonia at 800oC. This method allowed to prepare highly dispersed, X-ray amorphous vanadium nitride species, with high activity in the propane dehydrogenation. Compared to nitridation of supported vanadium oxide prepared via the ex-situ procedure, in-situ synthesized materials showed similar catalytic activity, in spite of having significantly lower vanadium loading. As an alternative for the preparation of supported nitride materials, a novel preparation procedure of bulk not supported nanocrystalline vanadium nitride with high surface area was presented. Instead of pure oxide powder (which was typically used in the preparation of high surface area vanadium nitride catalysts), a macroporous amine intercalated V2O5 was used as the starting material. The obtained nitride consisted of small crystallites and had a surface area up to 198 m2g-1. Moreover, this foam-derived VN showed significantly improved activity as a catalyst in propane dehydrogenation. This novel preparation method could also be extended to other systems such as ternary VMoxNy nitrides
The effect of flower removal on the growth and quality of bushes of two rose (Rosa L.) varieties
The present study was conducted during the period 2008â2011 in a production nursery without irrigation and established on grey-brown podzolic soil classified as soil class II. The study investigated the effect of regular flower removal on the growth and quality of bushes of the following rose (Rosa L.) varieties: a multi-flowered variety âArthur Bellâ and a large-flowered variety âBurgundâ. In the case of the multi-flowered variety âArthur Bellâ, flower removal was found to have a significant effect on the number and total length of shoots growing from the bud union in bushes. On the other hand, this practice was not shown to have an effect on the growth and quality of bushes of the large-flowered variety âBurgundâ. In the case of bushes of the studied varieties budded on Rosa multiflora Thunb. rootstock, the study showed significant differences in plant growth and branching between years. In 2009, after spring frosts that damaged young shoots and as an effect of a lower amount of rainfall by about 60 mm during the growing season, a much worse quality of rose bushes was obtained than in the other years
The effect of rootstocks on the efficiency of a nursery of sweet cherry (Prunus avium L.) trees cv. âReginaâ
During the period 2006â2009 in Lublin, a study was conducted to determine the effect of five rootstocks: âColtâ, âF12/1â, sweet cherry (Prunus avium L.), âGiSelA 5â, and âPiastâ, on bud take in the cultivar âReginaâ, the quality of budded trees and the efficiency of a sweet cherry tree nursery. The highest percentage of bud take in cherry trees cv. âReginaâ and the best efficiency of the sweet cherry tree nursery were obtained for the rootstocks âPiastâ and âColtâ. In two years during the three-year study period, the rootstock was found to significantly affect the efficiency of the sweet cherry tree nursery. When grafted on the rootstocks âColtâ and âPiastâ, a significantly higher percentage of trees met the requirements of the Polish Standard PN-R-67010 than on the clonal rootstock âGiSelA 5â. Under the tested conditions, the quality of maiden sweet cherry trees cv. âReginaâ grafted on the dwarfing rootstock âGiSelA 5â was lowest
The impact of environmental conditions on water salinity in the area of the city of InowrocĆaw (north-central Poland)
The article presents the influence of natural and anthropogenic factors on the chemical and physical properties of surface and ground waters in the area of the city of InowrocĆaw. It has been shown that the properties of the waters were most strongly affected by the specific geological structure (the city is located within the Zechstein salt dome) as well as the long-term influence of a salt mine and soda plant. The composition of most analysed samples was dominated by Ca 2+ , Na + and Cl - ions. In places of heavy industrial activity, some water parameters were several time higher than permissible values according to Polish standards. It is concluded that, due to the threat to the cityâs ground drinking water resources and fertile soils, the surface and ground waters in the area in question require permanent monitoring
Short bowel syndrome and severe skin toxicity as a complication of FOLFOX chemotherapy with panitumumab in a patient with colorectal cancer â a case report
The combination of monoclonal antibodies targeting epidermal growth factor receptor (EGFR) with chemotherapy is the standard treatment in advanced colorectal cancer without mutations in the RAS and BRAF genes. We present a case of a 55-year-old female patient with unacceptable skin toxicity and short bowel syndrome caused by palliative FOLFOX chemotherapy combined with panitumumab. In 2012, after the emergence of an artificial anus due to gastrointestinal obstruction in the course of rectal cancer, the patient underwent inductive chemotherapy, preoperative chemoradiotherapy, and radical surgery. Tubular adenocarcinoma G2, ypT2N0 was diagnosed. In 2013 and 2015 she underwent two additional surgeries including intestinal resection due to obstruction of the gastrointestinal tract and enterovaginal fistula. In February 2018 she was qualified for palliative chemotherapy because of inoperable relapse. Due to very good performance status (PS0) and absence of mutations of RAS and BRAF genes, regardless of being underweight and suffering from loose stools persisting from the time of surgery, FOLFOX chemotherapy with panitumumab was introduced. After the second administration of drugs an acne-like rash, hand-foot syndrome, and diarrhoea appeared. Intensification of symptoms and manifestations of short bowel syndrome were observed afterwards. Topical treatment of skin lesions, doxycycline, and anti-diarrhoeal therapy were introduced, with a mediocre therapeutic effect. Imaging confirmed disease stabilisation, but due to the deterioration of both performance status and life quality, anti-cancer treatment was discontinued. This case draws attention to the necessity of caution while qualifying for potentially toxic combination chemotherapy
The effect of different types of rootstock on the quality of maiden trees of sweet cherry (Prunus avium L.) cv. âReginaâ
Over the period 2006â2009 in Lublin, a study was conducted to determine the effect of five types of rootstock: âColtâ, âF12/1â, sweet cherry (Prunus avium L.), âGiSelA 5â and âPiastâ mahaleb cherry (Prunus mahaleb L.), on the growth and quality of maiden sweet cherry trees cv. âReginaâ in a commercial nursery. Based on the three-year average, rootstocks were shown to have a significant effect on the investigated quality characteristics of maiden sweet cherry trees. Trees budded on âColtâ vegetative rootstock were characterized by strongest growth and best quality. In each year, they were thicker, higher and better branched than sweet cherries on the rootstock. Under the tested conditions, âGiSelA 5â dwarf rootstock significantly reduced the growth and quality of budded sweet cherry trees in the nursery. During the period 2007â2009, no physiological incompatibility symptoms were observed âReginaâ sweet cherry cv. and âPiastâ seedling rootstocks. The growth of trees budded on âPiastâ mahaleb cherry was poorer than on âColtâ clonal rootstock, but it was stronger than on âF12/1â and Prunus avium L. rootstocks
Zapalenie palcĂłw jako objaw chorobowy wystÄpujÄ cy nie tylko w spondyloartropatii zapalnej
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W praktyce reumatologicznej najczÄĆciej spotykamy siÄ z zapaleniem palcĂłw w przebiegu spondyloartropatii zapalnej; nie moĆŒemy jednak zapomnieÄ, ĆŒe nie jest to jedyna jednostka chorobowa, w ktĂłrej wystÄpuje ten objaw. To waĆŒne, poniewaĆŒ mimo wspĂłlnego mianownictwa leczenie jest rĂłĆŒne w zaleĆŒnoĆci od etiologii. Niniejsza praca ma na celu zapoznanie czytelnikĂłw z innymi przyczynami zapalenia palcĂłw.
Forum Reumatol. 2016, tom 2, nr 3: 106â110
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