Solution Processable Semiconductor Thin Films: Correlation Between Morphological, Structural, Optical and Charge Transport Properties

Cette thèse de doctorat est le résultat d’un travail de recherche multidisciplinaire réunissant divers concepts fondamentaux comme l'ingénierie et la caractérisation des couches minces, l'électrochimie ainsi que la physique des dispositifs à base de couches minces semiconductrices. L’objet des expériences menées lors du travail de thèse porte sur les couches minces semiconductrices et leurs interfaces avec des matériaux électroniques ou des couches diélectriques. Le but ultime de la thèse est de mettre en corrélation la morphologie, la structure cristalline et la structure électronique des couches minces, ainsi que leurs propriétés fonctionnelles, avec le fonctionnement des dispositifs électroniques de type transistors utilisant ces mêmes couches minces en tant que matériau actif. En outre, de nouvelles stratégies fondées sur des phénomènes ayant lieu aux interfaces électrolyte/couche mince semiconductrice ont été explorées afin de contrôler la conductivité électrique au sein des couches minces. Trois principaux systèmes chimiques ont fait l'objet d’études approfondies durant cette thèse: deux types de semiconducteurs organiques (oligomère et polymères dérivés d’azométhinethiophènes et dérivés solubles de pentacène) et un semi-conducteur métal-oxyde (le trioxyde de tungstène, WO3). Dans le but d’explorer les propriétés morphologiques de couches minces à base de semiconducteurs organiques, les microscopies à force atomique et à fluorescence en mode hyperspectrale ont été employées. Grâce aux observations réalisées par ces techniques, des hypothèses de corrélation ont été formulées entre les caractéristiques morphologiques et les propriétés de transport des porteurs de charges au sein des couches minces. La diffraction par rayons X en configuration glancing angle (GIXRD, utilisant de la lumière de synchrotron) a été utilisée pour examiner la structure cristalline des couches mais aussi pour en apprendre plus sur l'organisation moléculaire au sein de ces dernières. Pour les transistors en couches minces, une configuration de type bottom contact a été choisie. Les caractéristiques de transfert et de sortie ont été utilisées pour calculer la mobilité des porteurs de charges, le voltage de seuil du dispositif ainsi que le ratio ION/IOFF.----------Abstract This Ph.D. thesis is a result of multidisciplinary research bringing together fundamental concepts in thin film engineering, materials science, materials processing and characterization, electrochemistry, microfabrication, and device physics. Experiments were conducted by tackling scientific problems in the field of thin films and interfaces, with the aim to correlate the morphology, crystalline structure, electronic structure of thin films with the functional properties of the films and the performances of electronic devices based thereon. Furthermore, novel strategies based on interfacial phenomena at electrolyte/thin film interfaces were explored and exploited to control the electrical conductivity of the thin films. Three main chemical systems were the object of the studies performed during this Ph.D., two types of organic semiconductors (azomethine-based oligomers and polymers and soluble pentacene derivatives) and one metal oxide semiconductor (tungsten trioxide, WO3). To explore the morphological properties of the thin films, atomic force microscopy was employed. The morphological properties were further investigated by hyperspectral fluorescence microscopy and tentatively correlated to the charge transport properties of the films. X-ray diffraction (Grazing incidence XRD, GIXRD) was used to investigate the crystallinity of the film and the effect of the heat treatment on such crystallinity, as well as to understand the molecular arrangement of the organic molecules in the thin film. The charge transport properties of the films were evaluated in thin film transistor configuration. For electrolyte gated thin film transistors, time dependent transient measurements were conducted, in parallel to more conventional transistor characterizations, to explore the specific effects played on the gating by the anion and cation constituting the electrolyte. The capacitances of the electrical double layers at the electrolyte/WO3 interface were obtained from electrochemical impedance spectroscopy. In the context of ARTICLE 1, thin film transistors based on soluble pentacene derivatives (prepared by the research group directed by Professor J. Anthony, at the University of Kentucky) were fabricated and characterized. GIXRD results performed on the thin films suggested a molecular arrangement favorable to charge transport in the source-drain direction, with the π-

The assesment of relationship between the angulation of impacted mandibular third molar teeth and the thickness of lingual bone : a prospective clinical study

Our purpose was to investigate the relationship between the angulation of mandibular third molars and the thickness of the lingual bone, which can affect the risk of lingual nerve damage during lower third molars surgical extraction. This study consisted of 104 patients (42 males and 62 females), aged between 18-42 years (24.67 ± 6.11 years). Cone Beam Computed Tomography (CBCT) images were taken for preoperative assessment. The teeth were divided into four groups according to their positions: mesioangular, distoangular, vertical and horizontal. Lingual bone thickness around impacted teeth were measured at three points: cementoenamel junction (CEJ) of the mandibular second molar, mid-root of the impacted third molar, and apex of the impacted third molar root. Two predisposing factors of lingual nerve damage were recorded: lingual bone perforated by the impacted tooth and lingual bone thinner than 1 mm. Additionally, buccolingual angulations of the teeth in each group were measured. Impacted mandibular third molars were removed in usual way. One week after surgery, the patients were evaluated regarding lingual nerve paresthesia. None of the 104 patients experienced paresthesia, including the ones who had teeth with close proximity with lingual nerve. The mean thickness of bone was 1.21±0.63 mm at CEJ of the second molar; 1.25±1.02 mm at the mid-root; and 1.06±1.31 mm at the apex. Horizontally impacted teeth had thinner lingual bone at mid-root level (p=0.016). Buccolingual angulated teeth were more often associated with perforated lingual bone (p=0.002). Buccolingual and mesial/distal angulation had negative correlation with lingual bone thickness (p<0.05). As the buccolingual and mesiodistal angulations increase, lingual bone thickness decreases. Horizontally impacted teeth seemed to compromise the integrity of the lingual bone more than impacted teeth in other positions. During the surgery, thin or perforated lingual bone may result in displacement of the impacted tooth lingually

Binaural beats or 432 Hz music? which method is more effective for reducing preoperative dental anxiety?

The aim of this prospective clinical study was to investigate the effectiveness of binaural beats and music at a frequency of 432 Hz and compare which method is more effective for reducing preoperative dental anxiety in impacted third molar surgery. Ninety patients were randomly selected to the binaural beats group, music group and control group. Visual analog scale used to evaluate dental anxiety before the local anesthesia in the first measurement. Local anesthesia was applied to the all patients. Patients in the music group listened to 432 Hz tuned music using earphones for 10 minutes. Patients in the binaural beats group listened to binaural beats using earphones (for the right ear, 220 Hz and for the left ear 210 Hz) for 10 minutes. No special treatment was applied to the patients in control group. In the second measurement, dental anxiety was measured again in all three groups. For analysis of differences between three groups was used One way Anova and Kruskal Wallis test. Twenty seven male and 53 female patients included the study. In the first measurement, the same level of anxiety was recorded in all three groups. (p=0.811) There was a significant decrease in anxiety in both the binaural beats and music group in the second measurement. (p<0.001). Binaural beats and 432 Hz tuned music are a valid non pharmacological adjuvant to reduce dental anxiety in impacted third molar surgery. They have a positive effect to reduce the dental anxiety

Comparison of the prevalence and sonographic features of thyroid nodules accompanying autoimmune thyroid diseases

Introduction: The coexistence of thyroid nodules and autoimmune thyroid disease (ATD) has been widely reported. The aim of our study was to retrospectively evaluate the prevalence and sonographic features of malignancy of thyroid nodules in ATD patients. Material and methods: We retrospectively analysed data from 500 patients with ATD in our hospital. We recorded ultrasonographic, histopathological and laboratory features of these patients. Thyroid ultrasonography was performed on all the patients, as well as fine needle aspiration biopsy (FNAB) of the thyroid nodule, when required. Patients underwent operations depending on the result of the FNAB. Results: Of the 500 with ATD (400 female and 100 male; mean age = 42.4 years), 300 (60%) had Hashimoto&#8217;s thyroiditis (HT) and 200 (40%) presented with Graves&#8217; disease (GD). The frequency of thyroid nodules was statistically significantly higher in those with GD (37.8%) than in those with HT (24.3%) (p < 0.001). One hundred and forty-nine nodules underwent FNAB (37.8%, 76 out of 200 had GD and 24.3%; 73 out of 300 had HT). The results of the cytological examination were: non-diagnostic cytology, benign, malignant and indeterminate in 19.4%, 73.8%, 2% and 4.5% of the nodules, respectively. When 55 GD and 32 HT patients, on whom total thyroidectomy had been carried out, were evaluated, the incidence of thyroid carcinoma was similar between patients with GD (n = 3, 5.5%) and HT (n = 2, 6.3%) (p > 0.05). Conclusions: We observed that the prevalence of thyroid nodules in patients with GD was higher than patients with HT. However, in general, the characteristics of the nodules and FNAB results were similar in both ATDs. (Pol J Endocrinol 2010; 61 (6): 658-664)Wstęp: W licznych doniesieniach stwierdza się współwystępowanie guzków tarczycy i autoimmunologicznych chorób tarczycy. Celem pracy była retrospektywna ocena występowania i sonograficznych cech złośliwości guzków tarczycy u pajcentów z autoimmunologicznymi chorobami tarczycy (ATD, autoimmune thyroid disease). Materiał i metody: Analizie retrospektywnej poddano dane 500 pacjentów z ATD, u których przeprowadzono badania ultrasonograficzne, histopatologiczne i laboratoryjne. U wszystkich pacjentów wykonano badanie ultrasonograficzne oraz, w zależności od wymagań, biopsję aspiracyjną cienkoigłową (BAC). Pacjentów poddano operacji w zależności od wyniku BAC. Wyniki: Spośród 500 pacjentów z ATD (400 kobiet i 100 mężczyzn, średnia wieku: 42,4 lat), u 300 (60%) stwierdzono zapalenie tarczycy Hashimoto (HT, Hashimoto thyroids), a u 200 (40%) chorobę Gravesa (GD, Graves disease). U pacjentów z GD stwierdzono statystycznie wyższą częstość występowania guzków tarczycy (37%) w porównaniu z pacjentami z HT (24,3%) (p < 0,001). Wykonano BAC 149 guzków, w 37,8% (76 z 200) przypadków z GD i w 24,3% ( 73 z 300) z HT. Wyniki badania cytologicznego: cytologia niediagnostyczna (19,4%), guzki łagodne (73,8%), guzki złośliwe (2%) i guzki o pośredniej złośliwości (4,5%). Spośród 55 pacjentów z GD i 32 z HT, u których wykonano tyroidektomię totalną, stwierdzono podobną częstość występowania raka tarczycy - u pacjentów z GD (n = 3, 5,5%), a u pacjentów z HT (n = 2, 6,3%) (p > 0,05). Wnioski: Zaobserwowano wyższą częstość występowania guzków tarczycy u pacjentów z GD w porównaniu z pacjentami z HT. Natomiast charakterystyka guzków i wyniki BAC nie różniły sie w obu typach ATD. (Endokrynol Pol 2010; 61 (6): 658-664

Acutely infected teeth: to extract or not to extract?

Abstract: Not only laymen but also dentists generally believe that extraction of acutely infected teeth should be avoided until the infection subdues by using systemic antibiotics. The aim of this study was to compare perioperative complications in routine extractions of acutely infected teeth with extractions of asymptomatic teeth. This prospective study was performed with 82 patients. Severe pain on percussion of the relevant tooth was considered as basic criteria for acute infection. The acutely infected teeth were labeled as the study group (n = 35) and the asymptomatic teeth as the control group (n = 47). The extractions were done using standard procedures. The amount of anesthetic solution used and duration of extractions were recorded. Postoperative severe pain and exposed bone with no granulation tissue in the extraction socket were indications of alveolar osteitis (AO). The level of statistical significance was accepted as 0.05. Symptoms that could indicate systemic response, including fever, fatigue, and shivering were not found. There was no statistically significant difference between groups in terms of AO, amount of anesthetic solution used, and duration of extraction. The presence of an acute infection characterized by severe percussion pain is not a contraindication for tooth extraction. Infected teeth should be extracted as soon as possible and the procedure should not be postponed by giving antibiotics

Density functional theory study of interactions between carbon dioxide and functionalized polyhedral oligomeric silsesquioxanes

Polyhedral Oligomeric Silsesquioxanes (POSS) are cage-structured inorganic–organic hybrid materials which can be used in various industrial applications. It is recently discovered that POSS structures with certain functional groups can be solubilized in supercritical CO2 allowing their applications in environmentally benign supercritical processing of materials. In this theoretical study, nature and energetics of the interactions of octatrifluoropropyl POSS, octatrifluoromethyl POSS, and octamethyl POSS with CO2 are investigated according to the principles of density functional theory (DFT) by use of Gaussian 09 software. Simulations show that CO2-octamethyl POSS pair has hydrogen bonding between the O atom of CO2 and the H atom of the methyl group, and CO2-octatrifluoromethyl POSS pair has interactions between the C atom of CO2 and the F atom of the trifluoromethyl group. CO2-octatrifluoropropyl POSS pair is found to have both interaction types. The octamethyl, the octatrifluoromethyl and the octatrifluoropropyl POSS structures have interaction energies of −2.18 kcal/mol, −3.10 kcal/mol, and −3.77 kcal/mol, respectively. This shows that the presence of Lewis acid–Lewis base interaction between C and F instead of hydrogen bonding between O and H atoms enhances the interaction of the molecule with CO2, while the presence of both interactions between the octatrifluoropropyl POSS-CO2 pair makes the intermolecular interaction even stronger

Pancreatic Injury Caused By A Fall From Height: Transection at the Tail

SUMMARY: Isolated pancreatic injury due to blunt abdominal trauma is rare and may be clinically difficult to diagnose. Parenchymal injuries may not be recognized during initial evaluation. We report the case of a 30-year-old male presented to the Emergency Department (ED) with the complaint of persistent abdominal pain, nausea, and vomiting. His medical history revealed that he fell from a height of approximately 1.5 meters 1 day ago and hit an iron block. He was presented and discharged from another hospital ED. Contrast enhanced computerized tomography (CECT) of the abdomen was ordered during his second presentation and revealed pancreatic parenchymal contusion, laceration, and transection at the tail of pancreas. Our findings suggest that, when there is high index of suspicion for pancreatic injury, a CECT should always be ordered. ÖZET: Künt abdominal travmaya bağlı izole pankreas yaralanması nadirdir ve klinik olarak tanı konulması zordur. Parankimal yaralanmalar ilk değerlendirme sırasında ayırt edilemeyebilinir. Bu yazıda, devam eden karın ağrısı, bulantı ve kusma yakınması ile acil servise başvuran 30 yaşındaki bir hasta sunuldu. Hastanın öyküsünde bir gün önce 1.5 metre yükseklikten demir bir blok üzerine düştüğü ve başvurduğu başka bir hastanenin acil servisinden taburcu edildiği öğrenildi. ikinci başvurusu sırasında kontrastlı batın tomografisi çekildi ve pankreas parankiminde kontüzyon, laserasyon ve pankreas kuyruk kesiminde kopma tespit edildi. Pankreas yaralanmasına ait yüksek şüphe mevcut ise kontrastlı batın tomografisi her zaman istenmelidir. Key words: Abdominal trauma, computed tomography, pancreatic injury, Anahtar sözcükler: Karın travması, bilgisayarlı tomografi, pankreas yaralanmas