154 research outputs found
Is the Złoczew lignite deposit geologically suitable for the first underground gasification installation in Poland?
The present study focuses on alternative methods of exploiting lignite in comparison to conventional opencast mining
and combustion in power plants for the generation of electricity. In Poland, opencast lignite pits cover large areas,
creating social and environmental conflicts. In order to stabilise the production level of electricity and reduce the negative
effects of opencast mining, alternative ways of exploiting lignite are suggested, one of these being underground
gasification in situ. The Złoczew lignite deposit, which will most likely be exploited in the near future, provides an
opportunity to discuss the unconventional method of underground coal gasification (UCG). On the basis of technological
and geological criteria that have been established to determine the suitability of Polish lignite for underground
gasification, resources to be used this way have been estimated. Through gasification, over 15 million tonnes of lignite
can be utilised, which is about 2.5 per cent of resources of the Złoczew deposit intended for opencast mining. With this
in mind, we suggest to take action by starting a pilot installation, to be followed by a commercial one for underground
gasification after completion of superficial mining. Naturally, any future application of this method will be preceded by
assessment of geological conditions at the Złoczew opencast pit
What can be learned about the deposition and compaction of peat from the Miocene lignite seam exposed in the Chłapowo Cliff on the Polish coast of the Baltic Sea?
This study focuses on discussing the relationship between the accumulation of peat and its compaction in the overbank zone of the Miocene river system. The examined 2nd Lusatian lignite seam is characteristically interbedded with sandy deposits and these are less compressible than peat. Therefore, in favourable conditions such as those found at Chłapowo Cliff (on the Baltic Sea coast in northern Poland), it is possible to identify the effects of an even or uneven lowering of the mire surface, resulting from diversified compaction of the underlying phytogenic beds. The research problem was applied to two examples located close to each other within the lignite seam. The first case shows the accumulation of fresh peat layers of almost equal thickness, while the second one presents a reduction in the thickness of fresh peat beds over the fossilised channel-fill sandy body. Only the latter example allows us to calculate the peat-to-lignite compaction ratio.The results of the compaction ratio obtained, Cr ≈ 7.37, mean that the youngest, fresh peat layers were compacted at least 7 times, transforming them into lignite beds. However, such a high compaction value, estimated for the top layers of the Miocene mire, cannot be directly taken into account when reconstructing the total thickness of the peat seam prior to covering it with mineral overburden. The published peat-to-lignite compaction ratios, determined using other research methods, for the 2nd Lusatian lignite seam or its stratigraphic equivalents range from 1.7 to 6.0 in most cases, with averages of 2.2 to 4.0. The differences between the data in the literature and the results given in this paper are due to the fact that the process of peat/lignite compaction is ongoing and cumulative
What are cleats? Preliminary studies from the Konin lignite mine, Miocene of central Poland
Cleats (fractures, joints) are discontinuities in coals, including lignites. They are important in mining activity because of
their gas and water permeability in hard coal, and mainly because of their water permeability in lignites. As opposed
to hard-coal cleats, lignite cleats have not been studied in detail before. The present contribution does so, using as an
example the 1st Middle-Polish Lignite Seam (MPLS-1) in the Jóźwin IIB opencast mine in central Poland. It should be
mentioned here that any remarks in the present contribution concerning MPLS-1 refer exclusively to this lignite seam
in the Jóźwin IIB opencast mine.
The investigated discontinuities consist of two sets, i.e. the face and butt cleats, which are roughly oriented NW–SE and
NE–SW, respectively. The mean spacing of the face cleats is ~12.4 cm, while the mean spacing of the butt cleats is ~12.8
cm. The maximum average aperture is ~4.9 mm for the face cleats and ~4.1 mm for the butt cleats. The cleat spacing
and aperture do not depend on the lignite thickness, but the cleat spacing increases with increasing mineral-matter and
xylite content, whereas the aperture increases when the contents decrease. The regional folding and local salt diapirism
tentatively explain the formation of the orthogonal system of the lignite cleats, partly because of the parallelism of the
face cleats and the major tectonic directions in central Poland
Macroscopic lithotype characterisation of the 1st Middle-Polish (1st Lusatian) Lignite Seam in the Miocene of central Poland
The 1st Middle-Polish (1st Lusatian) Lignite Seam is exploited in open-cast mines in central Poland. A large number
of lignite lithotypes, grouped in four lithotype associations, are distinguished: xylitic, detritic, xylo-detritic and detro-xylitic lithotype associations, which show various structures. Each lithotype association was produced under specific
peat-forming environmental conditions. In the case of the lignite seams under study they represent all the main envi -ronments that are known from Neogene mires, i.e.: fen or open water, bush moor, wet forest swamp and dry forest swamp. For a simple and practical description in the field of both the lignite sections and borehole cores, a new codification
for lignite lithotypes is proposed. It is based on the codification of clastic deposits (lithofacies). The practical value of the new lignite lithotype codification is examined in three vertical sections of the 1st Middle-Polish Lignite Seam
Mutational analysis of the internal membrane proximal domain of the HIV glycoprotein C-terminus
AbstractThis study focuses on the long stretch of highly conserved amino acids in the membrane proximal part of the HIV-1 cytoplasmic tail (Env amino acids (aa) 706–718) upstream of the overlap with the tat and rev second coding exons. Changes in Env aa 713 and 715, although they did not affect Env function, abrogated replicative spread. Other amino acid substitutions, i.e., 706–712, 714 and 716, despite their conservation, did not result in defective replicative phenotypes even in primary peripheral blood lymphocytes. Our results point to their involvement in presently unrecognized essential Env functions pertinent only in in vivo. Interestingly, changes in the codons for residues 717–718 as well as some mutations in residues 714–716 abrogated Gag expression but still allowed expression of functional Env in a rev-independent manner. This could be due to the inactivation of a rev-regulated negative element within the respective nucleotide sequence (8354–8368)
Malformations of cortical development in children : clinical manifestation, neuroimaging and neuropathology in selected cases
Cerebral cortical development can be divided into three steps: cellular proliferation, neuronal migration and organization.
Based on known pathologic, genetic and neuroimaging features a classification for malformations of cortical
development was proposed by Barkovich in 2001, and updated in 2005. Malformations of cerebral cortex development
(MCCD) often demonstrate epileptic seizures and delay in psychomotor development. About 20-40% of children with
epilepsy are drug-resistant and there is a large paediatric population requiring epilepsy surgery operations. In our work
we performed clinical analysis of 68 children with MCCD treated in our hospital between 2000 and 2006. In our work to
consider the type of MCCD we used the updated classification scheme proposed by Barkovich et al. We analyzed
epilepsy, gestational and perinatal history, initial symptoms, time to establishing full diagnosis and
neurodevelopmental/IQ status. In our results we found that despite similar clinical manifestation neuropathological
basis could be significantly different, and vice versa: children with nearly identical neuropathological findings could have
completely different neurological and radiological symptoms. Children with drug-resistant epilepsy are potential
candidates for neurosurgical treatment; especially lesionectomies in such cases could be very promising in terms of
epilepsy management and quality of life as well
Impact of the -174G/C interleukin-6 (IL-6) gene polymorphism on the risk of paediatric ischemic stroke, its symptoms and outcome
Ischemic stroke remains one of the top ten causes of death in children. There is evidence for the role
of pro-inflammatory cytokines, such as IL-6 and the -174G>C promoter polymorphism of the IL-6 gene, in the occurrence
and outcome of stroke in adults. The aim of the present study was to determine a possible association between
the -174G>C IL-6 polymorphism and occurrence of paediatric stroke, its symptoms and outcome. The study group consisted of 340 individuals: 80 stroke children, 122 parents of patients and
138 controls. The -174G/C polymorphism was genotyped using the RFLP method. For the analysis of the relationship
between genotypes and stroke we used two alternative methods: the case-control model and the transmission test
for linkage disequilibrium using data from families. We observed no differences in the transmission of alleles from parents to children. We also did not find any
statistical differences in distribution of genotypes and alleles between patients and controls. However, the analysis showed
that post-stroke epilepsy was genotype-dependent. All children with epilepsy were G allele carriers and none of them
was a CC homozygote whereas about 25% of children without epilepsy had the CC genotype. Our study did not show any associations between the IL-6 -174 G>C polymorphism and the occurrence
of stroke but we observed a relation between post-stroke epilepsy and the G allele carrier-state
Polimorfizm C242T genu kodującego cytochrom b-245 alfa nie jest związany z udarem niedokrwiennym mózgu u dzieci : analiza wewnątrzrodzinna i badanie kliniczno-kontrolne
Background and purpose: Reactive oxygen species play an
important role in the physiology and pathology of cerebral
arteries, including ischaemic stroke. The cytochrome b-245
alpha gene (CYBA) encodes cytochrome b-245 alpha light
chain (p22phox peptide), a critical element of NAD(P)H
oxidases, the most important source of superoxide anion in
the cerebral arteries. To search for genetic factors associated
with paediatric ischaemic stroke, the possible association
between CYBA gene C242T polymorphism and the disease
was evaluated.
Material and methods: The study group consisted of 238 in -
dividuals: children with ischaemic stroke (n = 70), their biological parents (n = 118) and children without any symptoms of stroke (n = 50). The C242T polymorphism was
genotyped using polymerase chain reaction – restriction fragment length methodology. To evaluate the possible association between polymorphism and stroke, the transmission disequilibrium test and the case-control method were applied.
Results: The C242 allele was transmitted more frequently
than 242T (62.2% vs. 37.8%) but observed frequencies did not differ significantly from expected (p = 0.10). There were
also no significant differences in allele and genotype distribution between patients and control subjects (patients: CC –
50.0%, CT – 38.6%, TT – 11.4% vs. controls: CC – 52.0%,
CT – 36.0%, TT – 12.0%).
Conclusions: The study did not show that the C242T polymorphism of the CYBA gene is a risk factor of ischaemic stroke in childre
Polimorfizm C242T genu kodującego cytohrom b-245 alfa nie jest związany z udarem niedokrwiennym mózgu u dzieci: analiza wewnątrzrodzinna i badanie kliniczno-kontrolne
Background and purpose
Reactive oxygen species play an important role in the physiology and pathology of cerebral arteries, including ischaemic stroke. The cytochrome b-245 alpha gene (CYBA) encodes cytochrome b-245 alpha light chain (p22phox peptide), a critical element of NAD(P)H oxidases, the most important source of superoxide anion in the cerebral arteries. To search for genetic factors associated with paediatric ischaemic stroke, the possible association between CYBA gene C242T polymorphism and the disease was evaluated.
Material and methods
The study group consisted of 238 individuals: children with ischaemic stroke (n = 70), their biological parents (n = 118) and children without any symptoms of stroke (n = 50). The C242T polymorphism was genotyped using polymerase chain reaction – restriction fragment length methodology. To evaluate the possible association between polymorphism and stroke, the transmission disequilibrium test and the case-control method were applied.
Results
The C242 allele was transmitted more frequently than 242T (62.2% vs. 37.8%) but observed frequencies did not differ significantly from expected (p = 0.10). There were also no significant differences in allele and genotype distribution between patients and control subjects (patients: CC – 50.0%, CT – 38.6%, TT – 11.4% vs. controls: CC – 52.0%, CT – 36.0%, TT – 12.0%).
Conclusions
The study did not show that the C242T polymorphism of the CYBA gene is a risk factor of ischaemic stroke in children.Wstęp i cel pracy
Reaktywne formy tlenu pełnią istotną funkcję zarówno w fizjologii, jak i patologii tętnic mózgowych, także w patogenezie udaru niedokrwiennego mózgu. Gen cytochromu b-245 alfa (gen CYBA) koduje lekki łańcuch cytochromu b-245 (białko p22phox), kluczowy składnik oksydaz NAD(P)H, najważniejszego źródła anionorodnika ponadtlenkowego w obrębie tętnic mózgowych. W niniejszej pracy, poszukując genetycznych czynników ryzyka predysponujących do udaru mózgu u dzieci, oceniano możliwe związki pomiędzy polimorfizmem C242T genu CYBA i chorobą.
Materiał i metody
W badaniu wzięło udział 238 osób: 70 dzieci z udarem niedokrwiennym mózgu, 118 ich biologicznych rodziców oraz 50 dzieci bez żadnych objawów udaru. Polimorfizm C242T genu CYBA genotypowano metodą polimorfizmu długości fragmentów restrykcyjnych w reakcji łańcuchowej polimerazy. Do oceny możliwych związków pomiędzy polimorfizmem i udarem zastosowano dwie niezależne metody: wewnątrzrodzinny test transmisji i badanie kliniczno-kontrolne.
Wyniki
Allel C242 był częściej przekazywany chorym dzieciom przez heterozygotycznych rodziców niż allel 242T (62,2% w porównaniu z 37,8%), jednak obserwowane częstości nie odbiegały znamiennie od oczekiwanych (p = 0,10). Nie wykazano także znaczących różnic w rozkładzie alleli i genotypów pomiędzy pacjentami i dziećmi z grupy kontrolnej (pacjenci: CC – 50,0%, CT – 38,6%, TT – 11,4%; grupa kontrolna: CC – 52,0%, CT – 36,0%, TT – 12,0%).
Wnioski
Wyniki badań nie wykazały, aby polimorfizm C242T genu CYBA był czynnikiem ryzyka udaru niedokrwiennego u dzieci
Circadian Profile of Salivary Melatonin Secretion in Hypoxic Ischemic Encephalopathy
Purpose. In the present study, the salivary melatonin secretion in the hypoxic ischemic encephalopathy (HIE) children was measured. The logit model was fitted to the data to obtain the salivary dim light melatonin onsets (DLMOs), and the results were compared with the values estimated from the classic threshold method with a linear interpolation and those previously published for the blood measurements. Materials and Methods. 9 patients suffering from HIE aged from 65 to 80 months were included in the study. The melatonin levels were assessed by a radioimmunoassay (RIA). The diurnal melatonin secretion was estimated using a nonlinear least squares method. Student’s t-test and the Mann–Whitney U test were used for the comparisons of the obtained parameters. Results. The circadian profiles of the melatonin secretion for both calculation methods do not differ statistically. The DLMO parameters obtained in the blood and saliva samples in children with hypoxic is chemic encephalopathy were similar
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