Virtual planning of dental implant placement using CT double-scan technique : own experience

Background: The correctness of CT performed with the use of a double-scan technique is the basis for achieving proper quality of 3D reconstructions of the maxilla or mandible and subsequent virtual planning of dental implant placement. The aim of this study was the presentation of the methodology of computed tomography scanning and own experience with the use of the double-scan technique. Material/Methods: The study group included 26 individuals who underwent MDCT with a double-scan technique using a MDCT scanner SOMATOM Sensation (Siemens, Germany). The parameters of the examination: slice-collimation 10x0.75 mm, slice-thickness 0.75 mm. The first CT scan in the procedure was the scan of the patient wearing a radiological prosthesis and occlusal index, which was followed by a separate scan of the radiological prosthesis. These two CT scans were copied and transferred to PC with Procera Software program (Nobel Biocare, Sweden) where dental implant placement was virtually planned. Results: In all 26 patients, precise three-dimensional reconstructions of the anatomical structure were obtained. In 11 patients, on the basis of the virtual planning, the implant placement was performed, 5 patients were referred to preparatory procedures, that is, restoration of the alveolar process, otolaryngological treatment of the maxillary sinuses. The remaining 10 patients did not qualify to the procedure because of unfavorable anatomical conditions. Conclusions: Correct computed tomography with double-scan technique enables virtual planning of dental implant placement, on the basis of which the real procedure of implantation can be performed

Response of Cladocera Fauna to Heavy Metal Pollution, Based on Sediments from Subsidence Ponds Downstream of a Mine Discharge (S. Poland)

Mining is recognized to deeply influence invertebrate assemblages in aquatic systems, but di erent invertebrates respond in di erent ways to mining cessation. Here, we document the response of the cladoceran assemblage of the Chechło river, S. Poland (southern Poland) to the cessation of Pb-Zn ore mining. The aquatic system includes the river and associated subsidence ponds in the valley. Some ponds were contaminated during the period of mining, which ceased in 2009, while one of the ponds only appeared after mining had stopped. We used Cladocera to reveal how the cessation of mine water discharge reflected on the structure and density of organisms. A total of 20 Cladocera taxa were identified in the sediment of subsidence ponds. Their density ranged from 0 to 109 ind./1 cm3. The concentrations of Zn, Cd, Cu and Pb were much higher in sediments of the ponds formed during peak mining than in the ponds formed after the closure of the mine. Statistical analysis (CCA) showed that Alonella nana, Alona a nis, Alona sp. and Pleuroxus sp. strongly correlated with pond age and did not tolerate high concentrations of heavy metals (Cu and Cd). This analysis indicated that the rate of water exchange by the river flow and the presence of aquatic plants, a ect species composition more than pond age itself

Genome instability in Chironomus annularius sensu Strenzke (Diptera, Chironomidae): A biomarker for assessment of the heavy metal contaminants in Poland

We studied the effect of heavy metal contaminations on genome instability of Chironomus annularius sensu Strenzke from three sampling sites on the River Chechło valley in southern Poland and a control site in Saraya, Bulgaria. The analysis of the heavy metal concentrations in sediments at the three river sites indicated concentrations higher than those in the fossil reference data (Zn 83-160 times, Pb 64-250 times, and Cd 210-793). According to the geoaccumulation index (Igeo), the sediments at all Chechło stations were classified as extremely polluted (Igeo class 6) by Cd, Pb and Zn while they were much less polluted by Cu (classes 1-3). The concentration of Cd, Pb and Zn in the sediments studied exceeded 21-79, 11-44 and 18-34 times the toxic effect threshold (TET) respectively; therefore, the sediments potentially have detrimental effects on the fauna. Genome instability was determined by somatic structural chromosome alterations (mainly heterozygous inversions) in the salivary gland chromosomes of C. annularius. On the basis of the number and frequency of these aberrations the somatic (S) and cytogenetic (C) indices were calculated as these indices allow a better quantification of the impact of heavy metals on organisms living in sediments. In the three Chechło sampling sites somatic aberrations occurred at a frequency significantly higher than in the control site (P<0.001). The three Chechło samples possess a high spectrum of somatic rearrangements with S index varying from 1.5 to 2.23 while in control site, S is 1.08. The C index of C. annularius from the polluted river sites varied from 0.163 to 0.380, far in excess of the C value of the control site (1.0), indicating strong pollution (<0.5) according to previous studies. In addition, a high level of inherited aberrations was detected (19 inherited band sequences, two of which were new). In all river stations the inverted homozygous band sequences A2.2 occurred in a high frequency (85%) and no standard sequences (A1.1) were observed. The transcription activity of Nucleolar Organizers (NORs) in chromosome arms A, C, E, G was often damaged and NOR activity was completely suppressed in 12.48% of larvae. Moreover, appearance of malformations in the external morphology of larvae was detected in 16.67% of larvae from all polluted sites. Therefore, the genome instability as estimated by two cytogenetic indices is a good biomarker of long-term toxicity and could be successfully implemented in the sediment monitoring procedures. 

Comparison of selected parts of larval morphology in some species of the genus Chironomus (Diptera: Chironomidae) using Scanning Electron Microscope

Comparison of small sized and weakly chitinized structures such as the labrum (labral setae SI-SIII, labral lamella, tormal bar, pecten epipharings) and the maxilla (maxillary palp, lacinial chaeta) is provided in larvae of Chironomus plumosus, C. balatonicus, C. usenicus C. melanotus, C. acerbiphilus, and C. riparius using Scanning Electron Microscope (SEM). The general morphological structures of the labrum and the maxilla were similar in all of the Chironomus larvae. They differed only in fine details such as labral seta, mainly S I. Seta S I is always plumose on each side and differently figured: elongated in C. balatonicus, C. plumosus, C. melanotus and C. usenicus; rounded in C. acerbiphilus and C. riparius. Some differences were also observed in the shape, length or ratio of lacinial chaetae (LCh I, LCh II). Based on morphological variation in the larvae of some Chironomus species, results indicated that the SEM method is apparently beneficial and useful in the analysis of smaller and weakly chitinized morphological structures such as the labrum and the maxilla

Fauna bezkręgowców w wysokogórskich potokach Kaukazu

Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej nauk

The Impact of Pollution on Diversity and Density of Benthic Macroinvertebrates in Mountain and Upland Rivers

This article summarizes the studies concerning the impact of pollutants on benthic macroinvertebrate communities in the mountain and upland rivers of southern Poland. The Carpathian Raba River, which in the 1960s retained its natural character and had good water quality, was considered as a reference in terms of benthic macroinvertebrate communities. The other two analyzed rivers were polluted to different degrees. The Carpathian Dunajec River was contaminated mainly by sewage from small towns and treatment plant, while the upland Vistula River mainly by sewage from the Upper Silesian Industrial Region and saline waters from coal mines. In studied ecosystems in response to pollutions, a rapid increase in density of fauna caused mainly by the massive development of Oligochaeta was found. In the mountain river, the impact of contamination on macroinvertebrate diversity was negligible. There, taxa considered as indicators of clean water (Ephemeroptera, Plecoptera, and Trichoptera) were abundant and their diversity was similar to that of an uncontaminated river. In the heavily polluted upland Vistula River, the sites with a muddy bottom were dominated by Oligochaeta (99.4–99.9%), while at sites with stony bottoms, apart from Oligochaeta, there were also Chironomidae, Gastropoda, and Hirudinea. In comparison to the 1950s, all Ephemeroptera, Plecoptera, Odonata, Trichoptera, and Megaloptera were extinct

The importance of scanning electron microscopy (sem) in taxonomy and morphology of Chironomidae (Diptera)

The paper reports on the value of scanning electron microscopy (SEM) in the taxonomy and morphology of Chironomidae. This method has been relatively rarely used in Chironomidae studies. Our studies suggest that the SEM method provides a lot of new information. For example, the plastron plate of the thoracic horn of Macropelopia nebulosa (Meigen) under light microscopy is visible as points, while under SEM we have found that it consists of a reticular structure with holes. By using SEM a more precise picture of the body structure of Chironomidae can be revealed. It allows researchers to explain inconsistencies in the existing descriptions of species. Another advantage of the SEM method is obtaining spatial images of the body and organs of Chironomidae. However, the SEM method also has some limitations. The main problem is dirt or debris (e.g. algae, mud, secretions, mucus, bacteria, etc.), which often settles on the external surface of structures, especially those which are uneven or covered with hair. The dirt should be removed after collection of chironomid material because if left in place it can become chemically fixed to various surfaces. It unnecessarily remains at the surface and final microscopic images may contain artifacts that obscure chironomid structures being investigated. In this way many details of the surface are thus unreadable. The results reported here indicate that SEM examination helps us to identify new morphological features and details that will facilitate the identification of species of Chironomidae and may help to clarify the function of various parts of the body. Fast development of electron microscope technique allows us to learn more about structure of different organisms

Chironomus polonicus sp. n. (Diptera: Chironomidae) from southern Poland

Michailova, Paraskeva, Kownacki, Andrzej, Langton, Peter H. (2013): Chironomus polonicus sp. n. (Diptera: Chironomidae) from southern Poland. Zootaxa 3599 (6): 564-576, DOI: 10.11646/zootaxa.3599.6.

Larva of Glyptotendipes (Glyptotendipes) glaucus (Meigen 1818) (Chironomidae, Diptera) : morphology by Scanning Electron Microscope (SEM), karyotype, and biology in laboratory conditions

Kownacki, Andrzej, Woznicka, Olga, Szarek-Gwiazda, Ewa, Michailova, Paraskeva (2016): Larva of Glyptotendipes (Glyptotendipes) glaucus (Meigen 1818) (Chironomidae, Diptera) — morphology by Scanning Electron Microscope (SEM), karyotype, and biology in laboratory conditions. Zootaxa 4169 (3): 555-570, DOI: http://doi.org/10.11646/zootaxa.4169.3.