Mandibular second molar impaction - literature review and case reports

Aim: To assess the incidence of mandibular second molar impaction and the treatment methods for this condition.Materials and Methods: A retrospective review of the cases of patients diagnosed with impaction of mandibular molars at the Department of Oral Surgery of the Faculty of Dental Medicine - Plovdiv during the past 11 years was performed.Results: 962 patients with impaction of mandibular molars were operated on in the analyzed period. This diagnosis is relatively rare in second mandibular molars and represents 0.94% of all cases. Most often, diagnosis is based on clinical evidence of missing molars and on panoramic radiographs. In the cases described by us, only surgical treatment was used.Conclusion: The treatment of this condition is a challenge which requires an individual approach to each case and an assessment to determine what treatment approach is to be used - surgical or orthodontic

Razvoj transgene otpornosti šećerne repe na virus nekrotičnog žutila nerava repe (BNYVV)

Fragments of viral cDNA containing the coat protein gene of beet necrotic yellow vein virus were cloned in plant transformation vector pCAMBIA3301M with the bar gene as selectable marker. Vector pC3301MCPL carrying coat protein gene with leader sequence, and pC3301MCPS with coat protein gene, were used in Agrobacterium - mediated transformation of sugar beet. The transformation method used was based on the fact that sugar beet develops axillary shoots in in vitro conditions, when placed on media with citokinins. Since this ability is not genotype or ploidy dependant it is widely used for sugar beet vegetative multiplication. Sterile seedlings, with removed cotyledons and lower half of hypocotyl, were used as starting material. After transformation ex-plants were put on micropropagation medium with cephotaxime and phosphinotricyn (ppt), where axillary shoots started to develop. Since concentration of ppt was not selective enough, after two subcultivations it was increased twofold. Only one sample, transformed with pC3301MCPS preserved morphogenetic potential for micropropagatio, and it was tested for presence of COS fragment and bar gene bz PCR with soecific primers.Fragmenti virusne cDNK sa genom za protein omotača virusa nekrotičnog žutila nerava repe su klonirani u vektor za transformaciju biljaka pCAM-BIA3301M koji je sadržao bar gen kao selektivni marker. Vektori pC3301MCPL, sa genom za protein omotača virusa i njegovom lider sekvencom, i pC3301MCPS, sa genom za protein omotača, su korišćeni u tramsformaciji repe pomoću Agrobacterium-a. Metod transformacije se zasniva na sposobnosti repe da u uslovima in vitro razvije aksilarne pupoljke na podlozi sa citokininima. Pošto ova sposobnost ne zavisi od genotipa ili od nivoa plodnosti, postala je standardni metod za vegetativno umnožavanje repe. Kao početni materijal su korišćeni sterilni ponići kojima su odstranjeni kotiledoni i donja polovina hipokotila. Nakon transformacije eskplantati su postavljeni na selektivnu podlogu za mikropropagaciju sa cefotaksimom i fosfinotricinom (ppt) gde je došlo do razvoja bočnih pupoljaka. Po.sto koncentracija fosfinotricina nije bila dovoljno selektivna, ona je nakon dve subkultivacije dvostruko povećana. Samo je jedan uzorak, transformisan vektorom pC3301MCPS, nakon dve subkultivacije sačuvao mofrogenetski potencijal za mikropropagaciju, i bio testiran na prisustvo CPS fragmenta i bar gena PCR reakcijom sa specifičnim prajmerima

Design, Synthesen und Charakterisierung von n-Typ-Metalloxidhalbleitern als Interfacematerialien für (opto)-elektronische Bauelemente

Over the past few years, there have been a large number of efforts on wetchemical synthesis of semiconductor metal oxide nanoparticles (MeOxNPs) and metal oxide precursor solutions (sMeOx) due to their decisive role in research and development of new materials and devices. The main goal of the novel synthetic routes is and remains the development of new synthesis strategies and production methods for MeOx NPs and sMeOx allowing one to precisely predict the composition, structure, size and opto‐electronic properties. In this regard in‐depth studies of synthesis and product characterizations are an important step towards more new technological applications. In the present work various sol‐gel techniques, which should help preparation and processing of undoped and doped n‐type metal oxide semiconductor materials (ZnO NPs, Zn1‐xAlxO NPs, Zn1‐xCoxO NPs, Zn1‐xNixO NPs, Al3+ doped ZnO (sAZO), TiO2 NPs, LixTi1‐xO2 NPs) in the nanometer range, are slightly modified and performed. In order to find and to optimize a simple, cost‐effective, environmentally friendly and efficiently synthetic route the advantages and disadvantages of applied sol‐gel methods are in detail discussed and compared. Additionally, the reaction mechanisms which provide important and in‐depth insights in the formation of synthesized undoped and doped ZnO NPs, TiO2 NPs and sAZO are thoroughly analyzed. Using a wide range of characterization methods (UV‐Vis spectroscopy, XRD, SEM, TEM, FTIR spectroscopy, PL spectroscopy, Raman spectroscopy) and measurement techniques (Kelvin probe (WF), conductivity (σ)), the structural, morphological and opto‐electronic properties of produced n‐type metal oxide semiconductors (ZnO NPs, Zn1‐xAlxO NPs, Zn1‐xCoxO NPs, Zn1‐xNixO NPs, Al3+ doped ZnO (sAZO), TiO2 NPs, LixTi1‐xO2 NPs) in both bulk and thin transparent films are investigated and tested. The aim of those investigations is to gain sufficient information concerning the integration of synthesized binary metal oxides (ZnO NPs, Zn1‐xAlxO NPs, Zn1‐xCoxO NPs, Zn1‐xNixO NPs, Al3+ doped ZnO (sAZO), TiO2 NPs, LixTi1‐xO2 NPs) as interface materials or as intermediate layers in inverted organic BHJ solar cells (ioBHJ). According to achieved experimental results, the produced interfacial layers via doctor blading based on synthesized n‐type‐metal oxide semiconductor nanomaterials (ZnO NPs, Zn1‐xAlxO NPs, Zn1‐xCoxO NPs, Zn1‐xNixO NPs, Al3+ doped ZnO (sAZO), TiO2 NPs, LixTi1‐xO2 NPs) can satisfy even the most requirements for interface layers. They possess large band gaps (Eg) and the transmission (%T) of all thin transparent films in the visible range is more than ≥ 85%. The differences in the measured work functions (WF) are also not so much. The compared conductivity (σ) values confirmed that selected synthesis method and the applied coating technology can play an important role by producing thin interfacial metal oxide films with suitable physical and chemical properties. A direct comparison of synthesized (ZnO NPs, Zn1‐xAlxO NPs, Zn1‐xCoxO NPs, Zn1‐xNixO NPs, Al3+ doped ZnO (sAZO), TiO2 NPs, LixTi1‐xO2 NPs) as electron extraction layers or electron transport layers in ioBHJ solar cells provides that Al3+ doped ZnO precursor solutions (HT‐AZO or LT‐AZO) are in advantage towards particulate dispersions based on ZnO NPs. They have more compact and dense layers which include relatively good conductivity (σ) and higher transmission (%T). By the variation of their layer thickness no perceptible influence on the performance of ioBHJ solar cells are observed, compared to interfacial layers based on ZnO NPs. In addition, it is determined that TiO2 NPs and LixTi1‐xO2 NPs interface layers allow the construction of reproducible and efficiently ioBHJ solar cells and therefore they prove to be a good alternative for replacement of interface layers based on ZnO NPs. However, development and fabrication of efficient ioBHJ solar cells require intensive stability tests. The most significant studies up to now focus on fundamental degradation mechanisms of organic semiconductors, but not on the degradation behavior of metal oxide interfacial layers (MeOx NPs, sMeOx). In this regard, the effect of temperature, adsorption of oxygen (O2), diffusion of moisture or moisture vapor and UV‐light on the optical and electrical properties of metal oxide thin films (HT‐AZO or LT‐AZO) by applying damp heat test and UV radiation test were investigated and correlated to device degradation. The achieved experimental results show that the optical properties like transmittance (%T) and band gap (Eg) are not influenced by damp heat test and UV radiation test. It is recognized that the electrical properties of both HT‐ and LT‐AZO thin films, i.e. work function (WF) and conductivity (σ) showed evident degradation upon damp heat exposure indicating the strong interaction between the metal oxide surface and the ambient conditions leading to the formation of a depletion layer. Accelerated device degradation under damp heat testing underlines the formation of a barrier or depletion layer at the interface, reducing VOC, JSC, and FF.Metalloxide als transparente Leiter gewinnen immer mehr an Bedeutung bei der Entwicklung innovativer, maßgeschneiderter und anwendungsorientierter Lösungen für viele zukünftige Schlüsseltechnologien, etwa im Bereich der Energieumwandlung (Photovoltaik), gedruckten organischen Nanoelektronik, neuen Beleuchtungssystemen und Oberflächenbeschichtungen (Touchscreens). Die folgende Dissertation behandelt die Durchführung und Optimierung der Syntheseverfahren von Metalloxid-basierten Nanomaterialien (MeOx) mit spezifischen Funktionalitäten. Dazu schafft eine Reihe von Charakterisierungsmethoden und Messtechniken einen vollständigen Ausblick in der Struktur, Morphologie und chemischen Zusammensetzung dieser Halbleitermetalloxid-Materialien. Im Mittelpunkt stehen bewusst die anwendungsbezogenen Eigenschaften der hergestellten Metalloxide im Nanometerbereich und die Voraussetzungen, die sie als Interfacematerialien erfüllen müssen. Gedruckt auf Glas oder Folie weisen sie hohe optische Transparenz, einstellbare elektrische Leitfähigkeit, Flexibilität und Kosteneffizienz auf. Ihre Integrierung als dünne Extraktions- und Transportschichten (Interface-Elektroden) in der organischen Photovoltaik und die Analyse ihres Zersetzungsverhaltens führen zur Entwicklung und Realisierung stabiler und hocheffizienter organischer BHJ Solarzellen

Design, Synthesen und Charakterisierung von n-Typ-Metalloxidhalbleitern als Interfacematerialien für (opto)-elektronische Bauelemente

Metalloxide als transparente Leiter gewinnen immer mehr an Bedeutung bei der Entwicklung innovativer, maßgeschneiderter und anwendungsorientierter Lösungen für viele zukünftige Schlüsseltechnologien, etwa im Bereich der Energieumwandlung (Photovoltaik), gedruckten organischen Nanoelektronik, neuen Beleuchtungssystemen und Oberflächenbeschichtungen (Touchscreens). Die folgende Dissertation behandelt die Durchführung und Optimierung der Syntheseverfahren von Metalloxid-basierten Nanomaterialien (MeOx) mit spezifischen Funktionalitäten. Dazu schafft eine Reihe von Charakterisierungsmethoden und Messtechniken einen vollständigen Ausblick in der Struktur, Morphologie und chemischen Zusammensetzung dieser Halbleitermetalloxid-Materialien. Im Mittelpunkt stehen bewusst die anwendungsbezogenen Eigenschaften der hergestellten Metalloxide im Nanometerbereich und die Voraussetzungen, die sie als Interfacematerialien erfüllen müssen. Gedruckt auf Glas oder Folie weisen sie hohe optische Transparenz, einstellbare elektrische Leitfähigkeit, Flexibilität und Kosteneffizienz auf. Ihre Integrierung als dünne Extraktions- und Transportschichten (Interface-Elektroden) in der organischen Photovoltaik und die Analyse ihres Zersetzungsverhaltens führen zur Entwicklung und Realisierung stabiler und hocheffizienter organischer BHJ Solarzellen

Teaching English through Poetry

Treball Final de Màster Universitari en Professor/a d'Educació Secundària Obligatòria i Batxillerat, Formació Professional i Ensenyaments d'Idiomes. Codi: SAP419. Curs: 2013/2014This didactic unit has been designed as an alternative to certain tasks that may be found in the traditional didactic units and it contains activities based on poetry. The main objectives are to motivate students of 1st of Bachillerato to read, write and speak in English through a variety of tasks based on poetry, and encourage teachers to use different teaching methods and techniques. In addition, the purpose of the activities is to enrich students’ curriculum and to reinforce some of their book exercises in order to avoid monotony and loss of interest. For this reason, those teachers who would like to implement the poetry based activities that I have designed may choose those they are most interested in and do not have to follow a specific sequence. Therefore, the teacher decides when to implement a particular activity. The reason why I suggest poetry is because poems are very entertaining to deal with while students constantly work on all skills simultaneously, even though they are not conscious about it sometimes. Poems’ structure makes them easy to read while its rhyme makes them extremely memorable. On top of that poems provoke people to express their personal opinion which is great for working on speaking.Finally, poems are authentic material that due to their appealing structure, rhythm and sound suggest a quick and enjoyable way of learning new vocabulary, revising grammar, improving pronunciation and promoting creativity. Poetry also gives teachers the opportunity to teach emotional intelligence, that is, to discriminate and label different emotions. All that being said, poetry should be given the same chance as other forms of literature

Effect of Ovarian Status on Reproductive Performance in Dairy Heifers Inseminated with Sexed Semen

Background: The intensive reproductive management in the dairy farms requires inclusion of a large group of replacement heifers in the breeding program for a shorter period. In this aspect, a creation of effective estrus synchronization protocols with timed artificial insemination (TAI) by sexed semen and optimization of the current ones have a crucial role for obtaining high pregnancy rate. These protocols are beneficial, because they led to reduced interval to first AI, lack of need for estrus detection, and allow obtaining a large group of female calves for on time. Because of limited fertilizing potential of sexed spermatozoa this type of semen is applied mainly for heifers, as fertility is higher compared to lactating cows. The main objective of the present study was to investigate the effect of ovarian status on the reproductive performance in dairy heifers subjected to estrus synchronization and timed artificial insemination with sexed semen. Materials, Methods & Results: Forty-eight Holstein healthy heifers separated in 2 groups were subjected to PGF2α-GnRH pre-treatment and Ovsynch or PRID-5-day estrus synchronization protocol and timed artificial insemination (TAI) with sex-sorted semen, staring 6 days after end of the hormonal pre-treatment. The ovarian status (presence of follicles with or not a corpus luteum) of the heifers at the begin of the treatment, on day of TAI and pregnancy rate in different groups were determined and compared. Additionally, the ovarian status at the begin of the treatment, ovarian status and size of preovulatory follicle (PF) on day of TAI and total values for both groups according to reproductive performance (pregnant or non-pregnant) were also analyzed. On day of TAI the animals with PF and a lack of corpus luteum (CL) in both groups were more that those with PF and CL (39.3% and 30% vs. 60.7 % and 70%), with significant (P < 0.05) difference in PRID-5-day group. The pregnancy rate tended to be higher in PRID-5 day than Ovsynch treatment (65% vs. 35.7%). A higher percentage (100% and 67.9%) of the pregnant animals in both treatments had not CL on day of TAI, and the size of the PF (1.58 ± 0.12 cm and 1.64 ± 0.13 cm) was increased (P < 0.05). Similar effects of the ovarian status on reproductive performance were obtained after a comparison of the total values between pregnant and non-pregnant animals. The percentage of heifers with observed PF without CL on day of TAI was significantly greater (P < 0.05) in pregnant compared to non-pregnant group (91.3% vs. 40%). The opposite dependence was determined for the parameter presence of follicles and corpus luteum (8.7% vs. 60%; P < 0.05).  Furthermore, the size of the PF measured immediately before TAI was increased in animals became pregnant (1.60 ± 0.12 cm vs. 1.34 ± 0.17 cm; P < 0.05). Discussion: The analysis of the obtained results showed that the ovarian status on day of TAI affects the reproductive performance in dairy heifers subjected to estrus synchronization and timed artificial insemination with sexed semen. Hormonal pre-treatment with onset of PRID-5-day protocol 6 days later and TAI with sex-sorted semen ensure acceptable pregnancy rate. The greater preovulatory follicle and a lack of corpus luteum before insemination provide significantly (P < 0.05) more pregnant animals, compared to the cases when CL is presented. Ultrasound determination of the ovarian function before insemination can be used in selection of heifers for TAI with sex-sorted semen.                   Keywords: heifers; estrus synchronization; sexed semen, pregnancy

Experimental determination of the heat exchange coefficient of industrial steam pipelines

The article discusses and analyses the factors related to the use of a thermal imaging camera to determine heat loss in industrial steam pipelines at factories from chemical and metallurgical industry, by measuring their surface temperature. The generally accepted enthalpy method for determination of the loss has serious drawback it gives accurate results, but in averaged units in which it is impossible to take account of the contribution of the different parts and components of the pipeline in the total heat loss. The unavailability of information on where, how and in what way along the route this loss is formed does not allow prompt and specific measures to be taken for its reduction. An attempt has been made to structure empirically a reliable analytic dependence for determination of the heat exchange coefficient, bringing together the various factors influencing the heat exchange. By the method of the least squares the free coefficient and the exponent have been determined of criterion equation satisfying initial and boundary conditions of the experiment. Based on the obtained results for determining the heat losses by measuring the surface temperature of steam pipelines with a thermal imaging system, a reliable and acceptable method is proposed, which has a place in engineering practice. For this purpose, an industrial experiment has been carried out at three actually operating steam pipelines of different diameters and steam parameters. A criterion equation has been derived that can be used as a mathematical model for software products with a practical orientation for regular assessment of heat losses of steam pipelines. Values of heat losses determined through energy balance of heat carrier and heat flux from the outer surface of the steam pipelines have been compared. Results for the heat exchange coefficient, obtained through a balance have been compared with the analytically determined values based on current standards. A new method has been developed for express evaluations of the current heat losses of the steam pipeline in real time, as the sum of the losses through its individual components gives as average values 9÷12 % increased results for the losses compared to the enthalpy method. Its great advantage is that it can be used selectively to determine the losses through individual sections of the steam pipeline