122 research outputs found
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Control strategies for exothermic batch and fed-batch processes A sub-optimal strategy is developed which combines fast response with a chosen control signal safety margin. Design procedures are described and results compared with conventional control.
There is a considerable scope for improving the temperature control of
exothermic processes. In this thesis, a sub-optimal control strategy
is developed through utilizing the dynamic, simulation tool. This
scheme is built around easily obtained knowledge of the system and
still retains flexibility. It can be applied to both exothermic batch
and fed-batch processes. It consists of servo and regulatory modes,
where a Generalized Predictive Controller (GPC) was used to provide
self-tuning facilities.
The methods outlined allow for limited thermal runaway whilst keeping
some spare cooling capacity to ensure that operation at constraints
are not violated. A special feature of the method proposed is that
switching temperatures and temperature profiles can be readily found
from plant trials whilst the addition rate profile Is capable of
fairly straightforward computation. The work shows that It is
unnecessary to demand stability for the whole of the exothermic
reaction cycle, permitting a small runaway has resulted in a fast
temperature response within the given safety margin.
The Idea was employed for an exothermic single Irreversible reaction
and also to a set of complex reactions. Both are carried out in a
vessel with a heating/cooling coil. Two constraints are Imposed; (1)
limited heat transfer area, and (11) a maximum allowable reaction
temperature Tmax.
The non-minimum phase problem can be considered as one of the
difficulties in managing exothermic fed-batch process when cold
reactant Is added to vessel at the maximum operating temperature. The
control system coped with this within limits, a not unexpected result.
In all cases, the new strategy out-performed the conventional
controller and produced smoother variations in the manipulated
variable. The simulation results showed that batch to batch variations
and disturbances In cooling were successfully handled. GPC worked well
but can be susceptible to measurement noise.Higher Education Ministry and Scientific Researc
Differential Gene Expression Analysis and Clinical Correlations within Endemic Burkitt Lymphoma
Endemic Burkitt lymphoma (eBL) is the most common pediatric cancer in equatorial Africa and is associated with malaria and Epstein-Barr virus co-infections. Molecular alterations within the eBL tumor genome and transcriptome have not been adequately investigated or compared to sporadic Burkitt lymphoma (sBL). Given that eBL has distinct clinical presentations in the jaw as opposed to the abdomen which are associated with survival, we hypothesize that transcriptome sequencing (RNA-seq) and potentially underlying genetic alterations will enhance our understanding of pathogenesis. Our results compare genome-wide RNA transcript abundances between eBL tumors from children (ages 6-7 yrs) with Stage I (Jaw tumor, n=14) and Stage II (abdominal, n=24) disease from Western Kenya to previously published work analyzing sBL which present in older children residing in developed countries and that tend not to be associated with EBV. Our initial analysis confirms mutational changes with likely functional alterations in the genes ID3 and TCF3, the key regulators of oncogenic pathways implicated in BL. However, the specific mutations observed in sBL are at lower frequency within eBL cases. This work represents the first comprehensive gene expression profile analysis of different eBL tumors. Hierarchical clustering, gene ontology and pathway analysis will provide insight into pathogenesis and new targets for chemotherapy
Integrative microRNA and mRNA deep-sequencing expression profiling in endemic Burkitt lymphoma
BACKGROUND: Burkitt lymphoma (BL) is characterized by overexpression of the c-myc oncogene, which in the vast majority of cases is a consequence of an IGH/MYC translocation. While myc is the seminal event, BL is a complex amalgam of genetic and epigenetic changes causing dysregulation of both coding and non-coding transcripts. Emerging evidence suggest that abnormal modulation of mRNA transcription via miRNAs might be a significant factor in lymphomagenesis. However, the alterations in these miRNAs and their correlations to their putative mRNA targets have not been extensively studied relative to normal germinal center (GC) B cells.
METHODS: Using more sensitive and specific transcriptome deep sequencing, we compared previously published small miRNA and long mRNA of a set of GC B cells and eBL tumors. MiRWalk2.0 was used to identify the validated target genes for the deregulated miRNAs, which would be important for understanding the regulatory networks associated with eBL development.
RESULTS: We found 211 differentially expressed (DE) genes (79 upregulated and 132 downregulated) and 49 DE miRNAs (22 up-regulated and 27 down-regulated). Gene Set enrichment analysis identified the enrichment of a set of MYC regulated genes. Network propagation-based method and correlated miRNA-mRNA expression analysis identified dysregulated miRNAs, including miR-17~95 cluster members and their target genes, which have diverse oncogenic properties to be critical to eBL lymphomagenesis. Central to all these findings, we observed the downregulation of ATM and NLK genes, which represent important regulators in response to DNA damage in eBL tumor cells. These tumor suppressors were targeted by multiple upregulated miRNAs (miR-19b-3p, miR-26a-5p, miR-30b-5p, miR-92a-5p and miR-27b-3p) which could account for their aberrant expression in eBL.
CONCLUSION: Combined loss of p53 induction and function due to miRNA-mediated regulation of ATM and NLK, together with the upregulation of TFAP4, may be a central role for human miRNAs in eBL oncogenesis. This facilitates survival of eBL tumor cells with the IGH/MYC chromosomal translocation and promotes MYC-induced cell cycle progression, initiating eBL lymphomagenesis. This characterization of miRNA-mRNA interactions in eBL relative to GC B cells provides new insights on miRNA-mediated transcript regulation in eBL, which are potentially useful for new improved therapeutic strategies
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The structure of paranoia in the general population
Background
Psychotic phenomena appear to form a continuum with normal experience and beliefs, and may build on common emotional interpersonal concerns.
Aims
We tested predictions that paranoid ideation is exponentially distributed and hierarchically arranged in the general population, and that persecutory ideas build on more common cognitions of mistrust, interpersonal sensitivity and ideas of reference.
Method
Items were chosen from the Structured Clinical Interview for DSM-IV Axis II Disorders (SCID-II) questionnaire and the Psychosis Screening Questionnaire in the second British National Survey of Psychiatric Morbidity (n = 8580), to test a putative hierarchy of paranoid development using confirmatory factor analysis, latent class analysis and factor mixture modelling analysis.
Results
Different types of paranoid ideation ranged in frequency from less than 2% to nearly 30%. Total scores on these items followed an almost perfect exponential distribution (r = 0.99). Our four a priori first-order factors were corroborated (interpersonal sensitivity; mistrust; ideas of reference; ideas of persecution). These mapped onto four classes of individual respondents: a rare, severe, persecutory class with high endorsement of all item factors, including persecutory ideation; a quasi-normal class with infrequent endorsement of interpersonal sensitivity, mistrust and ideas of reference, and no ideas of persecution; and two intermediate classes, characterised respectively by relatively high endorsement of items relating to mistrust and to ideas of reference.
Conclusions
The paranoia continuum has implications for the aetiology, mechanisms and treatment of psychotic disorders, while confirming the lack of a clear distinction from normal experiences and processes
Packages of Care for Depression in Low- and Middle-Income Countries
In the first in a series of six articles on packages of care for mental disorders in low- and middle-income countries, Neerja Chowdary and colleagues discuss the treatment of depression
Cooperation between Russian research organizations and industrial companies: factors and problems
The study is focused on the cooperation of Russian companies with research organizations in implementing R&D projects during technological innovation. Taking into account behavioral changes, authors carry out a micro-level analysis based on empirical data of executive survey of over 600 Russian industrial firms (2011—2012) and about 350 research organizations and universities (2012). The authors emphasize the key factors of firms’ demand for outsourcing R&D reveal the main barriers to the development of university-industry cooperation and their particularities for different cooperation actors.
The analysis shows that there is a positive relation between the size of a company and R&D outsourcing. As for the factor of age, the highest cooperation activity of Russian firms is observed among enterprises founded over 20 years ago. As far as concernes cooperation activity of research organizations, large ones are significantly more likely to cooperate with business. A common prerequisite for research organizations' R&D cooperation with business is sufficient academic ranking.
Business and science evaluate differently various obstacles to effective cooperation. For firms, the main problems are the inflated costs of national R&Ds, insufficient research organizations’ orientation at company needs, and low quality of developments. As for representatives of research organizations, they mention as barriers primarily the lack of companies' receptivity to innovation and inadequate information about promising developments. Businesses are more optimistic about cooperation with science if they already have a relevant experience of interaction. In the case of research organizations we observe a different pattern: most problems seem more significant to organizations conducting R&D in business interests
The Earth: Plasma Sources, Losses, and Transport Processes
This paper reviews the state of knowledge concerning the source of magnetospheric plasma at Earth. Source of plasma, its acceleration and transport throughout the system, its consequences on system dynamics, and its loss are all discussed. Both observational and modeling advances since the last time this subject was covered in detail (Hultqvist et al., Magnetospheric Plasma Sources and Losses, 1999) are addressed
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