Dissertations / Theses on the topic 'H. nana'

Helicobacter pylori (H. pylori) infection causes achlorydria, depressed gastric acid barrier, impaired immune response and is suspected in bacterial overgrowth and diarrhoea. These features of the infection are known to cause significant malabsorption of nutrients and impairment of linear growth in children. The prevalence of H. pylori infection in children is known to be much higher in developing countries, especially among the lower socio-economic groups. The true prevalence of infection in urban children in Mexico and its impact on their growth are largely unknown. This study examined the prevalence of H. pylori infection in school children from an urban area in Northwest Mexico and attempted to identify the risk factors that predispose individuals to infection in childhood; as well as to relate the presence of this infection to growth of children. The cross-sectional study was conducted in 1997/98 in the poorest socio-economic sectors of the city of Hermosillo, Sonora, among 178 children aged 9 and 10 years. H. pylori status was determined in children by the 13C-urea breath test. Anthropometric (weight and height) and haemoglobin measurements along with analysis of faecal samples and a 24-hour dietary recall were carried out in each child. Family sociodemographic/socio-economic status and living conditions data were elicited from parents by interview via structured questionnaires. The overall prevalence rate of H. pylori infection for the children in Hermosillo as determined by this study was 47.1%. The findings indicate that rural-born father, number of siblings, the type of main water supply (one tap in the yard) and the sharing of bed by the study child are important risk factors for acquiring the H. pylori infection. A borderline significant but small effect of H. pylori infection on height for-age was observed in this study. H. pylori infection was found to be positively highly associated with Hymenolepis nana. No differences in mean energy, protein and iron intakes between H. pylori positive and negative children were observed. However, significant differences in the mean energy, protein and iron intakes were observed between boys and girls. H. pylori infection and enteric parasites were not significantly correlated with the presence of anaemia.

Lo scenario cosmologico LCDM prevede che si formino prima gli aloni di materia oscura di piccola massa e in seguito, tramite merging, aloni più massicci. In questo scenario gerarchico di formazione delle strutture, anche le galassie più massicce si sarebbero formate per continue aggregazioni di sistemi più piccoli, formatisi per primi. Ai fini di comprendere meglio la formazione e l'evoluzione delle strutture agli inizi dell'Universo, è di grande importanza lo studio delle galassie nane star-forming (irregolari e blu compatte), povere di metalli e ricche di gas. Lo scopo di questo lavoro è studiare la galassia star-forming DDO 68, una nana blu compatta ed estremamente povera di metalli, situata nel vuoto Lynx-Cancer, nell'Universo locale. Recenti osservazioni potrebbero costituire la prima prova osservativa di processi di merging gerarchico in atto su piccole scale di massa galattica. Per confermare o meno le evidenze di tali interazioni multiple in atto in questa galassia, abbiamo usufruito di nuove osservazioni spettroscopiche delle regioni H II di DDO 68, effettuate nella notte del 21 Febbraio 2017 con MODS1 e MODS2 Multi-Object Double Spectrographs, montati su LBT. Dai dati abbiamo derivato le velocità radiali e le abbondanze chimiche per ciascuna regione H II osservata; dal nostro studio è emersa una differenza in metallicità tra le regioni H II della coda, della testa e del corpo centrale della galassia. Questo potrebbe essere un segno di attività di merging in atto tra un corpo meno metallico, la coda, e uno relativamente più ricco di metalli, il corpo centrale. Potrebbe trattarsi anche di un sistema non interagente e la differenza in metallicità potrebbe anche essere spiegata con un gradiente di metallicità. Rimane il fatto che le nostre osservazioni confermano per DDO68 metallicità estremamente basse, tali da renderla un outlier nella relazione luminosità-metallicità, rendendola un probabile sistema in fase di merging.

Las enteroparasitosis intestinales constituyen un problema de salud pública en Perú, debido a que estos parásitos pueden ingresar al organismo por vía oral y hábitos higiénico-sanitarios deficientes que facilitan su transmisión y conservación. Cuando la carga de dichos parásitos es considerablemente alta o se acompaña de alteraciones en la inmunidad del hospedero, se pueden producir complicaciones que comprometen seriamente la salud del paciente. Sabemos que el control farmacológico de las parasitosis es efectivo y seguro. No obstante, sin autocuidado y mantenimiento sostenible de buenas condiciones higiénico-sanitarias, no es posible su erradicación. Considerando lo mencionado anteriormente, desarrollaré la presente investigación en una población escolar de la Institución Educativa N° 6041 “Alfonso Ugarte” del distrito San Juan de Miraflores para determinar la prevalencia de parasitosis intestinales. Se eligió una muestra representativa conformada de 116 niños de 8 a 13 años. Las muestras fecales obtenidas fueron analizadas utilizando: examen macroscópico, método directo, método de Parodi Alcaraz y test de Graham. El 85.3% de los alumnos examinados resultaron parasitados. La incidencia parasitaria fue mayor en mujeres (86.8%) comparado a los hombres (83.6%). La frecuencia parasitaria de acuerdo al Monoparasitismo de los grupos taxonómicos fueron 35.3% del Phylum Amoebozoa, 3.4% del Phylum Metamonada, 3.4% del Phylum Platyhelminthes, 0.9% del Phylum Bigyra y 0.9% del Phylum Nematoda, con las especies Entamoeba coli, Giardia lamblia, Hymenolepis nana, Blastocystis hominis y Enterobius vermicularis, respectivamente. La mayor frecuencia correspondiente al Biparasitismo fue la asociación de los Phyla Metamonada y Amoebozoa con 32.8%. La mayor frecuencia correspondiente al Triparasitismo fue la asociación de los Phyla Metamonada, Amoebozoa y Platyhelminthes con 1.7%. The intestinal enteroparasites constitute a public health problem in Peru, due to these parasites can enter the body by mouth and hygienic habits-poor health that facilitate its transmission and conservation. When the burden of such parasites is considerably high or is accompanied by alterations in the immunity of the host, it can produce complications which seriously compromise the health of the patient. We know that the pharmacological control of the parasitosis is effective and safe. However, self-care and sustainable maintenance of good hygienic and sanitary conditions, it is not possible to its eradication. Considering the above, I will develop this research in a school population of the Educational Institution N° 6041 "Alfonso Ugarte" of the district San Juan de Miraflores to determine the prevalence of intestinal parasitism. I chosen a representative sample consisted of 116 children 8 to 13 years old. Stool samples obtained were analyzed using: macroscopic examination, direct method, Parodi Alcaraz’s method and Graham’s test. The 85.3% of the students examined were parasitized. The parasitic incidence was higher in women (86.8%) compared to men (83.6%). The frequency of parasites according the Monoparasitism of taxonomic group was 35.3% of the Phylum Amoebozoa, 3.4% of the Phylum Metamonada, 3.4% of the Phylum Platyhelminthes, 0.9% of the Phylum Bigyra and 0.9% of the Phylum Nematoda, with the species Entamoeba coli, Giardia lamblia, Hymenolepis nana, Blastocystis hominis and Enterobius vermicularis, respectively. The highest frequency corresponding the Biparasitism was the association of the Phyla Metamonada and Amoebozoa with 32.8%. The highest frequency corresponding the Triparasitismo was the association of the Phyla Metamonada, Amoebozoa and Platyhelminthes with 1.7%.

L’objective est d’améliorer l’activité photocatalytique de TiO2 sous irradiations UV et Visible. Pour contourner les limites de TiO2 intrinsèque nous envisageons une fabrication de nanocomposite plasmonique à base de nanofils de TiO2 périodiquement organisés et assemblés avec des nanoparticules plasmoniques. Pour la fabrication des nanofils de TiO2 mécaniquement stables, deux approches ont été réalisées. La première approche est basée sur la croissance sélective en phase vapeur, la deuxième approche consiste en l’utilisation d’un moule de membranes AAO et d’un dépôt de films conformes par ALD. En parallèle les films de TiO2déposés par ALD sont assemblés avec les nanoparticules plasmoniques d’or. Les différentes architectures de TiO2 sont valorisées par des tests photocatalytiques (UV et Visible) sur les polluants modèles. Une nouvelle approche de la fabrication des films mesoporeux d’H-TiO2 avec efficacité photocatalytique à la fois sous irradiation UV et Visible est développée
The objective of this thesis is to improve the photo-response of well-known photocatalytic material such as TiO2, which is usually only active in the UV range. The basic idea is to assemble several approaches within one device to improve the photocatalytic properties: fabrication of periodically-organised TiO2 nanostructures and their assembly with plasmonic nanoparticles. Two fabrication strategies were investigated for these purposes. The first approach consists of selective vapour phase growth. The second approach implements the use of an AAO template. In parallel, TiO2 films deposited by ALD and assembled with plasmonic gold nanoparticles are investigated. The photocatalytic measurements on various TiO2 architectures were performed in both irradiation ranges UV and Vis. A new fabrication approach of mesoporous H-TiO2 films was developed giving promising results of photocatalytic efficiency improvement in both UV and Visible ranges

This thesis analyzes World Trade Organization Doha Round negotiation process and its implications for Turkey&rsquo
s relations with its neighbors. The thesis mainly focuses on two pillars of negotiating package, namely agricultural and non-agricultural products (NAMA) negotiations. Both segments of negotiations have different dimensions due to Turkey&rsquo
s regional and multilateral obligations. As a developing country, Turkey&rsquo
s position in agriculture is more in line with other developing countries
in NAMA however it defends more liberal policies because of its Customs Union with the EU. Results of Doha Round will affect not only Turkey but also Turkey&rsquo
s neighbors and these effects will be more dramatic in some of them. Chapter I is Introduction Chapter. Chapter II evaluates Doha Round in detail
Chapters III and IV examine agriculture and NAMA negotiations and their implications for Turkey. Chapter V evaluates other negotiation topics such as services, trade facilitation, environment and rules. Chapter VI analyzes Turkey&rsquo
s Customs Union with the EU and its bilateral trade arrangements. The last Chapter is the Conclusion.

The present thesis is focused on various methods of controlling electronic and geometrical structure of two-dimensional overlayers adsorbed on metal surfaces exemplified by graphene and hexagonal boron nitride (h-BN) grown on transition metal (TM) substrates. Combining synchrotron-radiation-based spectroscopic and various microscopic techniques with in situ sample preparation, we are able to trace the evolution of overlayer electronic and geometrical properties in overlayer/substrate systems, as well as changes of interfacial interaction in the latter.It is shown that hydrogen uptake by graphene/TM substrate strongly depends on the interfacial interaction between substrate and graphene, and on the geometrical structure of graphene. An energy gap opening in the electronic structure of graphene on TM substrates upon patterned adsorption of atomic species is demonstrated for the case of atomic oxygen adsorption on graphene/TM’s (≥0.35 eV for graphene/Ir(111)). A non-uniform character of adsorption in this case – patterned adsorption of atomic oxygen on graphene/Ir(111) due to the graphene height modulation is verified. A moderate oxidation of graphene/Ir(111) is found largely reversible. Contrary, oxidation of h-BN/Ir(111) results in replacing nitrogen atoms in the h-BN lattice with oxygen and irreversible formation of the B2O3 oxide-like structure.      Pronounced hole doping (p-doping) of graphene upon intercalation with active agents – halogens or halides – is demonstrated, the level of the doping is dependent on the agent electronegativity. Hole concentration in graphene on Ir(111) intercalated with Cl and Br/AlBr3 is as high as ~2×1013 cm-2 and ~9×1012 cm-2, respectively.     Unusual periodic wavy structures are reported for h-BN and graphene grown on Fe(110) surface. The h-BN monolayer on Fe(110) is periodically corrugated in a wavy fashion with an astonishing degree of long-range order, periodicity of 2.6 nm, and the corrugation amplitude of ~0.8 Å. The wavy pattern results from a strong chemical bonding between h-BN and Fe in combination with a lattice mismatch in either [11 ̅1] or [111 ̅] direction of the Fe(110) surface. Two primary orientations of h-BN on Fe(110) can be observed corresponding to the possible directions of lattice match between h-BN and Fe(110).     Chemical vapor deposition (CVD) formation of graphene on iron is a formidable task because of high carbon solubility in iron and pronounced reactivity of the latter, favoring iron carbide formation. However, growth of graphene on epitaxial iron films can be realized by CVD at relatively low temperatures, and the formation of carbides can be avoided in excess of the carbon-containing precursors. The resulting graphene monolayer creates a periodically corrugated pattern on Fe(110): it is modulated in one dimension forming long waves with a period of ~4 nm parallel to the [001] direction of the substrate, with an additional height modulation along the wave crests. The novel 1D templates based on h-BN and graphene adsorbed on iron can possibly find an application in 1D nanopatterning. The possibility for growing high-quality graphene on iron substrate can be useful for the low-cost industrial-scale graphene production.

Ziele: Mittels absolutquantifizierender Protonen-Magnet-Resonanz-Spektroskopie (1H-MRS) wollten wir das Ergebnis einer Vorstudie bestätigen, die im Frontallappen einen reduzierten Quotienten von myo-Inositol/Gesamtcreatin (mI/tCr) bei Depressiven fand. Darüber hinaus testeten wir den antidepressiven Effekt von Inositol als Add-on-Therapie. Methodik: Wir untersuchten Einzelvoxel (2 x 2 x 2 cm3) in der weißen Substanz der rechten und linken Präfrontalregion mit Hilfe eines 3-Tesla Bruker Medspec Systems (STEAM Sequenz, TR/TE/TM = 6000/20/30 ms). Die einzelnen Metabolite wurden anhand des cerebralen Wassers als internem Standard quantifiziert (nach dem LCModell). Es wurden 24 unmedizierte Patienten mit unipolaren depressiven Episoden mit 24 alters- und geschlechtsgematchten gesunden Kontrollen verglichen. In doppelblindem, Plazebo-kontrollierten Parallelgruppen-Design erhielten die Patienten täglich 18 Gramm Inositol oder Plazebo zusätzlich zu Citalopram über vier Wochen. Ergebnisse: An der Baseline unterschieden sich die mI-, Cholin- und N-Acetyl-Aspartat-Konzentrationen der Patienten nicht von jenen der Kontrollen. Es fanden sich keine sich keine signifikanten Unterschiede zwischen Inositol- und Plazebo-Gruppe. Überraschenderweise zeigten die depressiven Patienten an der Baseline gegenüber den Kontrollen signifikant höhere tCr-Konzentrationen (mmol/kg) links (5,57 ± 0,96 vs. 4,87 ± 0,63; + 15 %, p < 0,01) und rechts präfrontal (5,29 ± 0,92 vs. 4,46 ± 0,41; + 17 %, p < 0,01). Nach der Behandlung ergab sich eine Reduktion der tCr-Konzentration links- (Tag 28: 5,05 ± 1,16; – 12 %, p = 0,08) und rechtsfrontal (Tag 28: 4,61 ± 1,07; – 9 %, p = 0,09). Die tCr-Konzentrationen der Patienten am Tag 28 unterschieden sich nicht mehr von jenen der Kontrollen. Zusammenfassung: Wir zeigten eine reversible Steigerung der tCr-Konzentration der Patienten im Vergleich zu Kontrollen, die auf Veränderungen des Creatin-Transports oder der ATP-Synthese bei unmedizierter unipolarer Depression hinweisen könnte.
Objectives: By means of proton magnetic resonance spectroscopy (1H-MRS) with absolute quantification we wanted to confirm our previous finding of decreased ratios of the metabolites myo-Inositol/total creatine (mI/tCr) in the right frontal brain of depressives. Moreover, we tested the antidepressive effect of oral Inositol ingestion as add-on-therapy. We measured concentrations (mmol/kg ww) of mI, tCr (= Creatine + Phosphocreatine), Choline (Cho) and N-Acetyl-Aspartate (NAA) in the frontal brain. Methods: Single voxels (2x2x2 cm3) in the white matter of the left and right prefrontal region were examined in a three Tesla Bruker Medspec System (STEAM sequence, TR/TE/TM = 6000/20/30 ms). Metabolites were quantified using the LCModel. At baseline, 24 drug-free patients with unipolar depressive episodes were compared to 24 age and sex matched healthy controls. In a double blind, placebo controlled parallel-group design patients received daily 18 grams Inositol or placebo as an add on therapy to Citalopram over four weeks. Results: At baseline, mI, Cho and NAA concentrations showed no significant differences between patients and controls. The treatment with Inositol did not result in any significant differences to the treatment with placebo. Surprisingly the patients showed significant higher tCr concentrations in the left (5.57 ± 0.96 vs. 4.87 ± 0.63; + 15 %, p < 0.01) as well as in the right prefrontal region (5.29 ± 0.92 vs. 4.46 ± 0.41; + 17 %, p < 0.01) compared to controls. The treatment caused a trend towards a decrease of tCr in the left (day 28: 5.05 ± 1.16; – 12 %, p = 0.08) and in the right frontal hemisphere (day 28: 4.61 ± 1.07; – 9 %, p = 0.09) compared to baseline. The differences between the patients’ tCr at day 28 and the tCr of controls were no more significant. Conclusion: We have found a state dependent increase of tCr concentration indicating bifrontal deviations in Creatine transport or ATP synthesis in drug free unipolar depressives.

Magister Scientiae - MSc (Physics)
An increasing energy demand and growing environmental concerns regarding the use of fossil fuels in South Africa has led to the challenge to explore cheap, alternative sources of energy. The generation of electricity from Photovoltaic (PV) devices such as solar cells is currently seen as a viable alternative source of clean energy. As such, crystalline, amorphous and nanocrystalline silicon thin films are expected to play increasingly important roles as economically viable materials for PV development. Despite the growing interest shown in these materials, challenges such as the partial understanding of standardized measurement protocols, and the relationship between the structure and optoelectronic properties still need to be overcome.

Cette thèse étudie le problème de nano-positionnement à l'intérieur d'un microscope électronique à balayage (MEB). Pour obtenir des informations de position avec rapidité et précision, une installation dédiée composée d’un vibromètre placé à l'intérieur du MEB a été mise en œuvre. Cette approche diffère de méthodes basées sur le traitement d'images, car elle permet de saisir des données en temps réel sur le comportement dynamique des structures étudiées. Dans une première étude, les perturbations mécaniques agissant à l'intérieur de la chambre à vide du microscope ont été caractérisées et leurs sources ont été identifiées. Cela a démontré comment les vibrations mécaniques externes et les bruits acoustiques peuvent influer largement sur les composants à l'intérieur du MEB par couplage mécanique, limitant ainsi la précision des manipulateurs. Dans un deuxième temps, une micro-pince du commerce a été étudiée. Une différence entre ses comportements dans l'air et dans le vide a été mise en évidence, ce qui a permis d'obtenir deux modèles dynamiques pour cet organe terminal, un pour chaque environnement. Deux lois de commande ont été proposées (commande H-infini et commande basée sur un observateur d'état étendu), afin d'obtenir en temps réel un positionnement précis dans le vide, et d'atténuer les effets des perturbations mécaniques externes. Les résultats ont été validés en simulation et expérimentalement
This work studies the nano-positioning problem inside the scanning electron microscope (SEM). To acquire fast and accurate positional information, a dedicated setup was implemented consisting of a vibrometer placed inside the SEM. This approach differs from methods based on image processing, as it allows to capture real-time data on the dynamic behavior of structures. In a first study, the mechanical disturbances acting inside the microscope’s vacuum chamber were characterized and its sources were identified. This demonstrated how external mechanical vibrations and acoustic noises can largely influence the components inside the SEM through mechanical coupling, limiting the effective positioning precision of manipulators. Next, a commercial micro-gripper was studied, both in air and in vacuum, and the differences between its response were highlighted. This allowed to obtain two dynamic models for this end-effector, one for each environment. Two control laws were proposed (H-infinity control and Extended State Observer based control) for the system, to obtain a real-time, precise positioning in the vacuum environment and to attenuate the effects of the external mechanical disturbances. Results were demonstrated through simulation and experimental validation

碩士
國立中央大學
材料科學與工程研究所
103
This study reports the synthesis of proton-conducting Ba1-xSrxCe0.8-xZrxY0.2O3-δ (x =0, 0.2, 0.4) ceramics by using a combination of citrate-EDTA complexing sol-gel process and the composition-exchange method. Compared to the sintered oxides of similar composition prepared from conventional sol-gel powders,Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δoxides synthesized by sol-gel combined with the composition-exchange method are found to exhibit improved sinterability, higher conductivity, more homogeneous phase. Among all sintered oxides in this study, the Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δpellet fabricated by this new method has the highest conductivity, 0.017 S/cm at 800℃, which is higher than those pressed from conventional sol-gel powders. Based on the experimental results, we discuss the mechanism for improvement in these properties in terms of calcined particle characteristics. This work demonstrates thatBa0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δoxides synthesized by sol-gel combined with the composition-exchange method would be a promising electrolyte for H+-SOFC applications. A SrCe0.8Y0.2O3-δ-NiO anode functional layer was added between the Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δelectrolyte and the Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δ-NiO anode substrate to investigate its effect on the performance of single cells. Anode-supported electrolyte fuel cells were fabricated and tested. The single cell without SrCe0.8Y0.2O3-δ-NiO anode functional layer generated maximum power densities of 201.08 mWcm−2 at 800 °C. Electrochemical impedance spectroscopy (EIS) measurements for three cells revealed that the addition of the anode functional layer reduced the contact resistance as well as the polarization resistance for the cell, resulting thus in the improved cell performance.

Hydrated cement paste (HCP), which is present in various cement-based materials, includes a number of constituents with distinct nano-structures. The elastic properties of the HCP crystals are calculated using molecular dynamics (MD) methods. The accuracy of estimated values is verified by comparing them with the results from experimental tests and other atomistic simulation methods. The outcome of MD simulations is then extended to predict the elastic properties of the C-S-H gel by rescaling the values calculated for the individual crystals. To take into account the contribution of porosity, a detailed microporomechanics study is conducted on low- and high-density types of C-S-H. The obtained results are verified by comparing the rescaled values with the predictions from nanoindentation tests. Moreover, the mechanical behavior of the HCP crystals is examined under uniaxial tensile strains. From the stress-strain curves obtained in the three orthogonal directions, elastic and plastic responses of the HCP crystals are investigated. A comprehensive chemical bond and structural damage analysis is also performed to characterize the failure mechanisms of the HCP crystals under high tensile strains. The outcome of this study provides detailed information about the nonlinear behavior, plastic deformation, and structural failure of the HCP phases and similar atomic structures.

There has been growing interest in two-dimensional (2-D) crystals beyond graphene for next-generation nano-electronics. Transition metal dichalcogenides have been most widely studied, for their semiconducting characteristics and hence, potential applications. This interest has fueled many efforts to establish methods for synthesis of MoS2 layers, a most promising candidate, in controlled numbers over large areas. One of the most scalable methods is chemical vapor deposition (CVD). The current approaches to growth from the vapor phase are by and large very empirical. This thesis is hence concerned with the predictive synthesis of n-layered MoS2 using CVD uniformly over large areas and the correlation of growth parameters with the structural and electronic properties of the deposited films. A simple, relatively non-toxic and non-pyrophoric chemistry, consisting of Mo(CO)6 and H2S was first chosen for vapor phase synthesis. This chemistry allowed synthesis of MoS2 from precursors located outside of the growth reactor, a necessary condition for electronics device technology. Iterative thermodynamic modeling of the Mo-S-C-O-H system and growth was then done to identify the appropriate CVD process windows for the growth of pure MoS2, departures from stoichiometry, contamination and breakdown of equilibrium modelling. Remarkable agreement between theoretical modelling and actual growth has been observed leading to predictable deposition. Within these thermodynamic windows, the gas phase supersaturation were then reduced to obtain better kinetic control over crystal growth. It is shown that control of supersaturation at the very initial stages of growth is critical to reduce the nucleation density and hence obtain monolayers with small defect densities. In addition, it is shown that at higher temperatures the kinetics of nucleation and growth are determined by the supersaturation on the growth surface. Physico-chemical modelling reveals that this steady state supersaturation is determined by the kinetics of adsorption and desorption. All of this understanding has been used to realize a variety of structures from discrete crystalline islands- 30 nm to 150 microns- to deposits with controlled number of layers – n =1 to 6 or greater- uniformly over large areas on quartz and sapphire. Gas phase chemistry also affects the electrical characteristics of the as deposited layers. It is shown, for the first time, that by changing gas phase Mo to S ratios the stoichiometry of the deposited layers MoS2 can be made metal or chalcogen deficient. This yields MoS2 that can be either p-type or n-type. p-type and n-type MoS2 with mobilities up to 7.4 cm2/Vs and 40 cm2/Vs respectively are demonstrated. FETs fabricated on MoS(2-x) samples (increasing x) with varying stoichiometry showed a maximum on-current of 18 μA (4.5 μA/μm) in vacuum and 0.6 μA (0.15 μA/μm) in air for a drain bias Vds = 1 V. Sulphur deficiency also affect reliability. While samples with a higher concentration of sulphur vacancies have higher mobility in vacuum, the mobility degrades significantly in air and gets reversed on annealing in H2S. The details of such correlation between growth and electrical characteristics are discussed in this thesis.