Methane Activation and Functionalisation using Zinc-Modified Zeolites

This thesis has investigated methane activation and subsequent functionalisation over zinc-modified zeolites, predominantly where the zinc has been introduced by vapour deposition. Particular focus was paid to the role of the zeolite framework and the nature of the zinc active site on methane activation. Selective methane activation to form [ZnII-CH3] species was confirmed by 13C MAS NMR spectroscopy for three zeolite frameworks with substantially different micropore topologies (ZSM-5 (15), FER (10) and MOR (10)). For Zn(VD)/MOR, two signals were observed by 13C NMR spectroscopy, likely resulting from two distinct [ZnII-CH3] species present in the 12 MR and 8 MR side pockets, as supported by additional NMR experiments. The percentage of active zinc sites, measured through quantitative NMR spectroscopic studies, varied with the zeolite framework and was found to be ZSM‐5 (5.7 %), MOR (1.2 %) and FER (0.5 %). Furthermore, the vapour deposition sample Zn(VD)/CH4/ZSM-5 produced significantly higher levels of active zinc sites compared to the Zn(IE)/CH4/ZSM-5 ion exchanged sample (5.7% compared with 0.9%) highlighting that both zeolite framework and method of zinc introduction influence methane activation. The observed products of oxidation of the [ZnII-CH3] species are also shown to depend on the zeolite framework type and the oxidative conditions used. XANES analysis of the vapour deposition (VD) samples, Zn(VD)/ZSM-5 and Zn(VD)/MOR, highlighted the presence of a low energy band tentatively assigned to a [ZnI-ZnI] dimeric species. Samples prepared by ion exchange or zinc vapour deposition samples heated to 600 °C, which are no longer able to activate methane, do not show this lower energy band. EXAFS analysis suggested the VD samples can be fitted using a model containing both Zn-O and [ZnI-ZnI] in the first co-ordination sphere whilst IE and 600 °C sample can only be fitted using Zn-O. The XAS evidence supported by futher experiments led us to conclude that the [ZnI-ZnI] dimer is the active species in vapour deposition samples. Zinc catalysts prepared through zinc vapour deposition, ion exchange and impregnation using four different zeolite frameworks (ZSM-5 (12.5), BETA (12.5), MOR (10) and FER(10)) were tested for activity in the methane dehydroaromatisation (MDA) reaction. Overall, zeolite framework plays a key role in the MDA reaction with ZSM-5 proving to be the best host framework, in line with results presented in the literature for Mo catalysts. The method of zinc introduction, and therefore the active zinc species, was also crucial as zinc introduction by vapour deposition proved superior to both ion exchange and impregnation

Glutamate racemase from Mycobacterium tuberculosis inhibits DNA gyrase by affecting its DNA-binding

Glutamate racemase (MurI) catalyses the conversion of L-glutamate to D-glutamate, an important component of the bacterial cell wall. MurI from Escherichia coli inhibits DNA gyrase in presence of the peptidoglycan precursor. Amongst the two-glutamate racemases found in Bacillus subtilis, only one inhibits gyrase, in absence of the precursor. Mycobacterium tuberculosis has a single gene encoding glutamate racemase. Action of M.tuberculosis MurI on DNA gyrase activity has been examined and its mode of action elucidated. We demonstrate that mycobacterial MurI inhibits DNA gyrase activity, in addition to its precursor independent racemization function. The inhibition is not species-specific as E.coli gyrase is also inhibited but is enzyme-specific as topoisomerase I activity remains unaltered. The mechanism of inhibition is different from other well-known gyrase inhibitors. MurI binds to GyrA subunit of the enzyme leading to a decrease in DNA-binding of the holoenzyme. The sequestration of the gyrase by MurI results in inhibition of all reactions catalysed by DNA gyrase. MurI is thus not a typical potent inhibitor of DNA gyrase and instead its role could be in modulation of the gyrase activity

Rural Supremacy

The success of any brand depends on it acceptance by the consumers. This project highlights the rural buying behaviour. The rural consumers tend to show a closed mind towards branded goods and services. Though the current scenario is improved than the past but still large amount of rural market is untapped. The marketers now understand the potential at the bottom of the pyramid but there are doubts regarding the way this market can be reached and converted into customers. Many factors like income, education, media exposure, taste and preference etc, play an important role in driving the buying behaviour of the rural population. Often companies face problems in succeeding in the rural market, although they might have a good record in the urban market. This is because few companies fail to understand the difference between the urban market and the rural market. The marketing strategies adopted for the urban market cannot be used for the rural market also as it is a completely different mindset that is to be dealt with. However many big multinationals have now realized this need and have emerged with strategies specific to the rural market. For instance brands like Colgate, Lux, Coca Cola are few of the highest selling in the rural market. Through this project it is aimed to understand the reluctance consumers show towards branded products and for this purpose the case study of the company ‘ Everest Spices is used. The research is specifically based on the acceptance of branded spices in the rural market compared to the homemade spices which has been an age old traditio

Influence of Mainshock-Aftershock Sequence Selection Techniques in Quantifying Seismic Response

Past studies have observed increased vulnerability of the structures when subjected to mainshock-aftershock (MS-AS) ground motion sequences instead of mainshocks (MS) alone. The lack of availability of as-recorded real MS-AS ground motion sequences for the seismic performance assessment of the structure has led to the use of artificially generated sequences. This study aims to quantify the relationship between MS and AS ground motion characteristics in a MS-AS sequence. It also evaluates the need to utilize these relations in developing artificial MS-AS sequences for seismic response evaluation of structures. To this end, a real ground motion database comprising of 192 MS-AS sequences is compiled from different ground motion databases. A univariate and a multivariate linear regression model quantifying the relationship between MS and AS ground motion characteristics in a sequence are developed. Artificial MS-AS sequences are simulated using these regression models. An analytical nonlinear model of four story modern reinforced concrete moment frame building is subjected to sets of real and artificial MS-AS sequences through incremental dynamic analysis (IDA). The IDA results from each set of MS-AS sequences are used to generate seismic collapse fragility curves. The results indicate that the median collapse capacity for the building model calculated using artificial MSAS sequence set based on regression models developed in the study match closely with the real MS-AS sequence set.This research project is funded through Grant no. ECR/2017/000907 from SERB and DST, India. Their support is gratefully acknowledged. The authors also acknowledge the support of earthquake ground motion databases K-NET, KiK-net (http://www.kyoshin.bosai.go.jp/) and PEER NGA database (https://ngawest2.berkeley.edu/) for providing the ground motions for this study

Surname lists to identify South Asian and Chinese ethnicity from secondary data in Ontario, Canada: a validation study

<p>Abstract</p> <p>Background</p> <p>Surname lists are useful for identifying cohorts of ethnic minority patients from secondary data sources. This study sought to develop and validate lists to identify people of South Asian and Chinese origin.</p> <p>Methods</p> <p>Comprehensive lists of South Asian and Chinese surnames were reviewed to identify those that uniquely belonged to the ethnic minority group. Surnames that were common in other populations, communities or ethnic groups were specifically excluded. These surname lists were applied to the Registered Persons Database, a registry of the health card numbers assigned to all residents of the Canadian province of Ontario, so that all residents were assigned to South Asian ethnicity, Chinese ethnicity or the General Population. Ethnic assignment was validated against self-identified ethnicity through linkage with responses to the Canadian Community Health Survey.</p> <p>Results</p> <p>The final surname lists included 9,950 South Asian surnames and 1,133 Chinese surnames. All 16,688,384 current and former residents of Ontario were assigned to South Asian ethnicity, Chinese ethnicity or the General Population based on their surnames. Among 69,859 respondents to the Canadian Community Health Survey, both lists performed extremely well when compared against self-identified ethnicity: positive predictive value was 89.3% for the South Asian list, and 91.9% for the Chinese list. Because surnames shared with other ethnic groups were deliberately excluded from the lists, sensitivity was lower (50.4% and 80.2%, respectively).</p> <p>Conclusions</p> <p>These surname lists can be used to identify cohorts of people with South Asian and Chinese origins from secondary data sources with a high degree of accuracy. These cohorts could then be used in epidemiologic and health service research studies of populations with South Asian and Chinese origins.</p

GENDER, ENVIRONMENT AND LIVELIHOOD SECURITY: AN ALTERNATIVE VIEWPOINT FROM INDIA

Summary Using a case study from India, this article examines the limitations of populist ecofeminist thought. The case study shows that both men and women assume interchangeable roles as destroyers and conservers of the environment, depending on both the material relationship they have with their natural resources and the social context within which they operate. Secure livelihood opportunities and usufruct rights, and the existence of enabling institutional mechanisms are of considerable importance for people to have a stake in conserving their natural resources. The article further shows that if environment?focused development programmes are to be sustainable, it is necessary to develop a consultative process with both men and women, so that the concerns and needs of all social groups within a community are addressed. In the case of common property resources, the role of inter?village dialogues, which take into account the complex gender and social relations within and among the village communities, are of critical importance. RESUME Le genre, l'environnement, et la sécurité des moyens de vie: un point de vue alternatif en lnde Par le biais d'une étude de cas en Inde, l'article examine les limites de la pensée populiste de l'éco?féminisme. L'étude de cas démontre que les hommes comme les femmes assument des rôles interchangeables de destructeurs et de conservateurs de l'environnement, en fonction à la fois des rapports matériels qu'ils entretiennent avec les ressources naturelles et aussi, du contexte social au sein duquel ils opèrent. Les opportunités d'assurer les moyens de vie et les droits d'usufruit, et l'existence de mécanismes institutionnels qui facilitent ces opportunités sont d'une importance considérable si l'on veut que les membres de telles populations puissent participer activement à la préservation de leurs ressources naturelles. L'article démontre en outre que si les programmes de développement axés sur l'environnement veulent être permanents, il est nécessaire de développer un processus de consultation auprès des hommes et des femmes, de sorte que l'on puisse s'adresser aux inquiétudes et aux besoins de tous les groupes sociaux dans telle ou telle communauté. Dans le cas des ressources en copropriété, le rôle des dialogues inter?villageois sont d'une importante cruciale, dans la mesure où ces dialogues tiennent compte des relations complexes qui existent au niveau social et au niveau du genre au sein de ces communautés villageoises, et entre elles. RESUMEN Género, medio ambiente y seguridad de subsistencia: un punto de vista alternativo de la India Basándose en un caso de la India, este artículo examina las limitaciones del pensamiento populista ecofemenino. El estudio de este caso demuestra que tanto hombres como mujeres asumen roles intercambiables como destructores y conservadores del medio ambiente, dependiendo de su relación material con los recursos naturales, y del contexto social en el que operan. Las oportunidades de subsistencia y los derechos de usufructo, así como la existencia de mecanismos internacionales tienen una importancia considerable para asegurar la participación del pueblo a la hora de conservar recursos naturales. El artículo demuestra, además, que para alcanzar programas de desarrollo sostenibles ? enfocados hacia el medio ambiente ? es necesario poner en marcha un proceso de consulta con hombres y mujeres de tal forma que se discutan las preocupaciones y necesidades de todos los grupos sociales dentro de una comunidad. En el caso de propiedad común, el rol del diálogo entre comunidades cobra una importancia crucial, porque toma en consideración las complejas relaciones sociales y de género dentro de éstas, y en su contacto con otras similares

γ-H2AX+CD8+ T lymphocytes cannot respond to IFN-α, IL-2 or IL-6 in chronic hepatitis C virus infection

Background & AimsAge is the dominant prognostic factor influencing the natural history of hepatitis C virus (HCV) infection and treatment response. Accelerated lymphocyte telomere shortening in HCV infection correlates with adverse clinical outcomes. Critical telomere shortening generates double-stranded DNA breaks (DSB) inducing the DNA damage response, leading to replicative senescence. The phenotype and function of CD8+ T lymphocytes and the in vitro response to IFN-α in relation to the DNA damage response were investigated in patients with chronic HCV infection.MethodsCD8+ T lymphocytes with DSB were identified by expression of γ-H2AX (Ser-139) in 134 HCV-exposed subjects and 27 controls. Telomere length was determined by flow-FISH; cytokine expression by intracellular cytokine staining; in vitro responses to IFN-α, IL-2 or IL-6 by phospho-STAT1 (Y701) or phospho-STAT5 (Y694) expression.ResultsThe proportion of circulating CD8+γ-H2AX+ T lymphocytes rose with increasing fibrosis stage (p=0.0023). CD8+γ-H2AX+ T lymphocytes were enriched in liver compared to blood (p=0.03). CD8+γ-H2AX+ T lymphocytes demonstrated increased IFN-γ (p=0.02) and reduced IL-2 expression (p=0.02). CD8+γ-H2AX+ T lymphocytes failed to phosphorylate STAT1 in response to IFN-α compared to unfractionated CD8+ T lymphocytes (p <0.0001). More widespread failure of Jak/Stat signalling in CD8+γ-H2AX+ T lymphocytes was suggested by impaired phosphorylation of STAT1 with IL-6 (p=0.002) and STAT5 with IL-2 (p=0.0039) compared to unfractionated CD8+ T-lymphocytes.ConclusionsIn chronic HCV infection, CD8+γ-H2AX+ T lymphocytes are highly differentiated with shortened telomeres, are more frequent within the liver, are associated with severe fibrosis and fail to activate Jak/Stat pathways in response to IFN-α, IL-2 or IL-6, perhaps explaining treatment failure in those with severe fibrosis