913 resultados para 100103 Agricultural Molecular Engineering of Nucleic Acids and Proteins
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INTRODUCTION: Hepatitis B virus (HBV) infection is one of the most serious public health problems in the world. In Brazil, HBV endemicity is heterogeneous, with the highest disease prevalence in the North region. METHODS: A total of 180 samples were analyzed and subjected to polymerase chain reaction (PCR) and semi-nested PCR of the HBV S-gene, with the aim of determining the prevalence of HBV-DNA (deoxyribonucleic acid) in indigenous groups inhabiting the areas near the Curuçá and Itaquaí Rivers in the Javari Valley, State of Amazonas, Brazil. RESULTS: The prevalence of the HBV-DNA S-gene was 51.1% (92/180). The analysis found 18 of 49 (36.7%) samples from the Marubo tribe, 68 of 125 (54.4%) from the Kanamary, and 6 of 6 (100%) from other ethnic groups to be PCR positive. There was no statistically significant difference in gender at 5% (p=0.889). Indigenous people with positive PCR for HBV-DNA had a lower median age (p<0.001) of 23 years. There was no statistical difference found in relation to sources of contamination or clinical aspects with the PCR results, except for fever (p<0.001). The high prevalence of HBV-DNA of 75% (15/20) in pregnant women (p=0.009) demonstrates an association with vertical transmission. CONCLUSIONS: The results confirm the high prevalence of HBV-DNA in the Javari Valley, making it important to devise strategies for control and more effective prevention in combating the spread of HBV.
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Introduction Torque teno virus (TTV) and SEN virus are circular single-stranded DNA viruses that cause blood-borne infections. The SEN virus (SEN-V) was originally detected in the serum of an injection drug user infected with human immunodeficiency virus (HIV). Recently TTV was discovered as a potential causative agent of non-A-E hepatitis. The aim of this study was to investigate the prevalence of the SEN-V-D/H and TTV in HIV patients and healthy blood donors in Iran. Methods One hundred and fifty HIV patients with a mean age of 50.46 ± 18.46 years and 150 healthy blood donors with a mean age of 48.16 ± 13.73 years were included in this study. TTV and SEN-V were detected by the PCR and were quantitatively assayed by competitive PCR (nested and semi-nested PCR). Restriction fragment length polymorphisms (RFLPs) were used to determine the heterogeneity of TTV. Results TTV and SEN-V were detected 96 (64%) and 84 (56%) of 150 HIV patients respectively. These rates were 34% (n=51) and 37.33% (n=56) in healthy blood donors (significant, p<0.05). PCR detected SEN-V/TTV DNA from 32 of the healthy blood donors (21.33%), while 65 (43.33%) of HIV patients were positive for SEN-V/TTV DNA. Of 150 HIV patients, 32.66% and 23.33% were positive for SEN-V-H and SEN-V-D, respectively and 18.66% (n=28) were co-infected with SEN-V-D/H. Conclusions The prevalence of SEN-VD/H and TTV is higher in HIV patients than in healthy blood donors in Southern Iran. Our results suggest that TTV and SEN-V might play a role in the development of liver disease in patients with immunodeficiency diseases.
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AbstractINTRODUCTIONThe aim of this study was to detect the prevalence of the extended-spectrum beta-lactamase (ESBL)-encoding CTX-M gene in Escherichia coliisolates.METHODS:Phenotypic screening of 376 E. coli isolates for ESBL was conducted using disk diffusion. ESBL-producing isolates were tested using PCR and specific primers. The blaCTX-M cluster was identified using the RFLP method, and its genotype was sequenced.RESULTS:From 202 ESBL-producing E. coli , 185 (91.5%) possessed CTX-M genes. CTX-M-1 subtypes were found in 98% of the isolates. The blaCTX-M gene was identical to CTX-M-15.CONCLUSIONS:A high prevalence of CTX-M-1-producing E. coli apparently exists in Shiraz, Iran.
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ABSTRACTINTRODUCTION:In this study, the molecular characteristics of group A rotavirus (RVA) were compared in samples obtained before and after RVA vaccine-introduction in Brazil.METHODS:Eighty samples were screened for the presence of RVA. Positive samples were molecularly analyzed.RESULTS:RVA positivity was 16.9%, with a predominance of G2P[4]. Periods: pre-vaccination: predominance of IId (G1), IId (G2) lineages, and I1 and E1 genotypes; post-vaccination: predominance of Ib (G1), IIa, and IIc (G2) lineages and I2 and E2 genotypes.CONCLUSIONS:Although changes in RVA-circulation pattern were observed in the post-vaccination period, it could not be attributed to vaccination process.
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ABSTRACTINTRODUCTION:The larvicidal activity of oils, fatty acids, and methyl esters of Solanum lycocarpum fruit against Culex quinquefasciatus is unknown.METHODS:The larvicidal activity of samples of ripe and unripe fruit from S. lycocarpum was evaluated against third and fourth instar larvae of C. quinquefasciatus .RESULTS:The oils, fatty acids, and methyl esters of S. lycocarpum showed the greatest larvicidal effect (57.1-95.0%) at a concentration of 100mg/L (LC 50values between 0.70 and 27.54mg/L).CONCLUSIONS:Solanum lycocarpum fruit may be a good source of new natural products with larvicidal activity.
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Abstract INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is a nosocomial pathogen in community settings. MRSA colonized individuals may contribute to its dissemination; the risk of MRSA infection is increased in human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) patients, although the prevalence of colonization in this group is not well established. The present study addressed this issue by characterizing MRSA isolates from HIV/AIDS patients and their healthcare providers (HCPs) to determine whether transmission occurred between these two populations. METHODS: A total of 24 MRSA isolates from HIV-infected patients and five from HCPs were collected between August 2011 and May 2013. Susceptibility to currently available antimicrobials was determined. Epidemiological typing was carried out by pulsed-field gel electrophoresis, multilocus sequence typing, and Staphylococcus cassette chromosome (SCCmec) typing. The presence of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) and heterogeneous daptomycin-resistant Staphylococcus aureus (hDRSA) was confirmed by population analysis profile. Isolates characterized in this study were also compared to isolates from 2009 obtained from patients at the same hospital. RESULTS: A variety of lineages were found among patients, including ST5-SCCmecII and ST30-SCCmecIV. Two isolates were Panton-Valentine leukocidin-positive, and hVISA and hDRSA were detected. MRSA isolates from two HCPs were not related to those from HIV/AIDS patients, but clustered with archived MRSA from 2009 with no known relationship to the current study population. CONCLUSIONS: ST105-SCCmecII clones that colonized professionals in 2011 and 2012 were already circulating among patients in 2009, but there is no evidence that these clones spread to or between HIV/AIDS patients up to the 7th day of their hospitalization.
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Abstract: INTRODUCTION Characterization of Mycobacterium tuberculosis (MTB) isolates by DNA fingerprinting has contributed to tuberculosis (TB) control. The aim of this study was to determine the genetic diversity of MTB isolates from Tehran province in Iran. METHODS MTB isolates from 60 Iranian and 10 Afghan TB patients were fingerprinted by standard IS6110-restriction fragment length polymorphism (RFLP) analysis and spoligotyping. RESULTS The copy number of IS6110 ranged from 10-24 per isolate. The isolates were classified into 22 clusters showing ≥ 80% similarity by RFLP analysis. Fourteen multidrug-resistant (MDR) isolates were grouped into 4 IS6110-RFLP clusters, with 10 isolates [71% (95% CI: 45-89%)] in 1 cluster, suggesting a possible epidemiological linkage. Eighteen Iranian isolates showed ≥ 80% similarity with Afghan isolates. There were no strains with identical fingerprints. Spoligotyping of 70 isolates produced 23 distinct patterns. Sixty (85.7%) isolates were grouped into 13 clusters, while the remaining 10 isolates (14.2%) were not clustered. Ural (formerly Haarlem4) (n = 22, 31.4%) was the most common family followed by Central Asian strain (CAS) (n = 18, 25.7%) and T (n = 9, 12.8%) families. Only 1strain was characterized as having the Beijing genotype. Among 60 Iranian and 10 Afghan MTB isolates, 25% (95% CI: 16-37) and 70% (95% CI: 39-89) were categorized as Ural lineage, respectively. CONCLUSIONS A higher prevalence of Ural family MTB isolates among Afghan patients than among Iranian patients suggests the possible transmission of this lineage following the immigration of Afghans to Iran.
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Cardiovascular diseases (CVDs) are one of the leading causes of death and disability worldwide and one of its underlying causes is hypercholesterolemia. Hypercholesterolemia can have genetic (familial hypercholesterolemia, FH) and non-genetic causes (clinical hypercholesterolemia, CH), the first much more severe, with occurrence of premature atherosclerosis. While the pathophysiological role of homocysteine (Hcy) on CVD is still controversial, molecular targeting of protein by S and N-homocysteinylation offers a new paradigm to be considered in the vascular pathogenesis of hypercholesterolemia. On this regard, the present study aims to give new insights on protein targeting by Hcy in both CH and FH conditions. A total of 187 subjects were included: 65 normolipidemic and 122 hypercholesterolemic. Total (tHcy) and free (fHcy) fractions were quantified in serum samples after validation of an HPLCFD method, to assess S-homocysteinylation. Also, the lactonase (LACase) activity of paraoxonase-1 (PON1) was quantified by a colorimetric assay, as a surrogate of N-homocysteinylation. tHcy does not differ among groups. Nevertheless, fHcy declines in the hypercholesterolemic groups, with more evidence to the FH population. Consequently, there seems to be an increase of Shomocysteinylation, regardless of lipid lowering therapy (LLT). Also, despite of LLT use, LACase activity is lower in FH, thus the risk for protein N-homocysteinylation seems to be higher. Moreover, the decrease in LACase/ApoA1 and LACase/HDL ratios in FH, shows that HDL is dysfunctional in this population, despite its normal concentration values. Data supports that the pathophysiological role of Hcy on hypercholesterolemia may reside in its ability to post-translationally modify proteins. This role is particularly evident in FH condition. In the future, it will be interesting to identify which target proteins are modified and thus involved in vascular pathology progression.
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INTRODUCTION: Friedreich's ataxia is a neurodegenerative disorder whose clinical diagnostic criteria for typical cases basically include: a) early age of onset (< 20 or 25 years), b) autosomal recessive inheritance, c) progressive ataxia of limbs and gait, and d) absence of lower limb tendon reflexes. METHODS: We studied the frequency and the size of expanded GAA and their influence on neurologic findings, age at onset, and disease progression in 25 Brazilian patients with clinical diagnosis of Friedreich's ataxia - 19 typical and 6 atypical - using a long-range PCR test. RESULTS: Abnormalities in cerebellar signs, in electrocardiography, and pes cavus occurred more frequently in typical cases; however, plantar response and speech were more frequently normal in this group when the both typical and atypical cases were compared. Homozygous GAA expansion repeats were detected in 17 cases (68%) - all typical cases. In 8 patients (32%) (6 atypical and 2 typical), no expansion was observed, ruling out the diagnosis of Friedreich's ataxia. In cases with GAA expansions, foot deformity, cardiac abnormalities, and some neurologic findings occurred more frequently; however, abnormalities in cranial nerves and in tomographic findings were detected less frequently than in patients without GAA expansions. DISCUSSION: Molecular analysis was imperative for the diagnosis of Friedreich's ataxia, not only for typical cases but also for atypical ones. There was no genotype-phenotype correlation. Diagnosis based only on clinical findings is limited; however, it aids in better screening for suspected cases that should be tested. Evaluation for vitamin E deficiency is recommended, especially in cases without GAA expansion.
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Mycobacterium avium Complex (MAC) comprises microorganisms that affect a wide range of animals including humans. The most relevant are Mycobacterium avium subspecies hominissuis (Mah) with a high impact on public health affecting mainly immunocompromised individuals and Mycobacterium avium subspecies paratuberculosis (Map) causing paratuberculosis in animals with a high economic impact worldwide. In this work, we characterized 28 human and 67 porcine Mah isolates and evaluated the relationship among them by Multiple-Locus Variable number tandem repeat Analysis (MLVA). We concluded that Mah population presented a high genetic diversity and no correlations were inferred based on geographical origin, host or biological sample. For the first time in Portugal Map strains, from asymptomatic bovine faecal samples were isolated highlighting the need of more reliable and rapid diagnostic methods for Map direct detection. Therefore, we developed an IS900 nested real time PCR with high sensitivity and specificity associated with optimized DNA extraction methodologies for faecal and milk samples. We detected 83% of 155 faecal samples from goats, cattle and sheep, and 26% of 98 milk samples from cattle, positive for Map IS900 nested real time PCR. A novel SNPs (single nucleotide polymorphisms) assay to Map characterization based on a Whole Genome Sequencing analysis was developed to elucidate the genetic relationship between strains. Based on sequential detection of 14 SNPs and on a decision tree we were able to differentiate 14 phylogenetic groups with a higher discriminatory power compared to other typing methods. A pigmented Map strain was isolated and characterized evidencing for the first time to our knowledge the existence of pigmented Type C strains. With this work, we intended to improve the ante mortem direct molecular detection of Map, to conscientiously aware for the existence of Map animal infections widespread in Portugal and to contribute to the improvement of Map and Mah epidemiological studies.
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RESUMO: Os glicoconjugados que decoram a superfície celular e os lípidos e proteínas secretados ocupam o ponto de encontro onde normalmente ocorrem interacções críticas homólogas (hospedeiro-hospedeiro) e heterólogas (hospedeiro-patogénio). Apesar de ser largamente aceite que os glicanos são parte integrante do processo de imunidade, continua a não ser claro qual o papel que os glicanos, em toda a sua diversidade, tomam no quadro geral da imunidade. Os glicanos, que são frequentemente terminados por resíduos de ácido siálico, podem ser alterados por factores externos, tais como patogénios, ou por acontecimentos fisiológicos celulares específicos. Normalmente em posição terminal, as glico-estruturas que contêm ácido siálico assumem um papel fundamental numa quantidade substancial de receptores imunes envolvidos na adesividade e tráfico celular, tal como as Selectinas e as Siglecs, das quais se sabe apresentarem uma relevante função imune. À altura do início desta tese, era sabido que os ácidos siálicos expressos à superfície das células poderiam modular mecanismos importantes nas respostas imunes adaptativas. Considerando a posição de charneira que as células dendríticas (DCs) ocupam na transição da resposta imune inata para a adaptativa, antecipámos que os ácidos siálicos poderiam também modular mecanismos relevantes nas DCs humanas. As DCs têm uma função muito relevante na verificação e captura antigénica, migração para os gânglios linfáticos e apresentação antigénica aos linfócitos, uma sequência de funções que conduz, em ultima instância, à indução da resposta inata adaptativa. Considerando estas premissas, a nossa hipótese principal foi que os ácidos siálicos podem influenciar funções relevantes das DCs, tais como captura de antigénios, maturação, migração para os gânglios linfáticos e apresentação antigénica às células Para testar esta hipótese, dividimos o trabalho em quatro partes: 1) Analisámos os glicanos sialilados de superfície, expressos durante a diferenciação de monócitos humanos em DCs (moDCs). Os nossos dados mostraram que a expressão dos glicanos com ligações em O (O-glicanos) e sialilados em α2,3, assim como glicanos com ligações em N (N-glicanos) sialilados em α2,6 e α2,3 aumentou durante o processo de diferenciação das moDCs. Contribuindo para esta nova configuração glicosídica, três sialiltransferases (STs) poderão estar envolvidas: a ST6Gal-1 correlaciona-se com a expressão aumentada de N-glicanos sialilados em α2,6; a ST3Gal-1 contribui para a sialilação em α2,3 de O-glicanos, em especial de antigénios T; e a ST3Gal-4 poderá ser responsável pelo aumento de N-glicanos sialilados em α2,3. Após estímulo e consequente maturação das moDCs, ambos os níveis de expressão génica de ST6Gal-1 e ST3Gal-4 são negativamente modificados sendo, também, que a expressão de ST3Gal-1 varia consoante o estímulo. 2) Estudámos posteriormente as consequências da modulação dos ácidos siálicos de superfície nas funções das DCs. Observámos que a remoção dos ácidos siálicos de superfície diminui significativamente a capacidade de macropinocitose e endocitose mediada por receptores nas moDCs. Em contrapartida, o tratamento com sialidase aumentou significativamente a capacidade das moDCs para fagocitar Escherichia coli. Determinou-se também que este mecanismo requer a existência de ácido siálico presente nas E. coli indicando um mecanismo de interacção hospedeiro-patogénio dependente de ácido siálico em ambas as partes envolvidas. As moDCs tratadas com sialidase também apresentam um nível superior de expressão de moléculas de MHC e moléculas co-estimulatórias, sugerindo um fenótipo celular mais maduro. Recorrendo ao modelo de ratinho, utilizaram-se DCs derivadas de células da medula (BMDCs) de ratinhos deficientes em ST3Gal-1 e ST6Gal-1. Estes ensaios revelaram que quer a endocitose quer a maturação são influenciadas por modificações 37 nos glicanos sialilados em α2,3 ou α2,6. A detecção e quantificação de proteínas Nglicosiladas e sialiladas em α2,6 apontou para um potencial envolvimento de integrinas β2 nestes mecanismos. 3) O efeito da sialilação em α2,6 na migração das DCs para os gânglios linfáticos foi também analisado. Observámos que BMDCs deficientes para ST6Gal-1 apresentam uma redução de cerca de 50% nos níveis de migração das DCs para os gânglios linfáticos, tal como aferido em ensaios de inflamação in situ e estudos de transferência adoptiva de células. Uma redução dos níveis deste tipo de migração foi também observada quando BMDCs nativas foram transferidas para ratinhos receptores deficientes em ST6Gal-1. São, contudo, necessários mais ensaios de forma a identificar as moléculas envolvidas neste processo. 4) Por último, analisámos o impacto da sialilação na estimulação antigénica das DCs às células T. Assim, concluiu-se que moDCs tratadas com sialidase apresentam um nível de expressão superior de IL-12, TNF-ɑ, IL-6 e IL-10, e activação do factor de transcrição nuclear kappa B (NF-κB). As DCs tratadas com sialidase induziram uma maior proliferação nas células T, com expressão correspondente de interferão-γ. Este dado sugere que a remoção de ácidos siálicos de superfície contribui para o desenvolvimento de uma resposta pro-inflamatória do tipo 1 por células T auxiliares (resposta Th1). Considerando estes dados no seu todo, concluímos que o ácido siálico tem um papel marcante nas funções imunes das DCs. Alterações à concentração de ácido siálico à superfície das células podem alterar a endocitose/fagocitose, maturação, migração para os tecidos e gânglios linfáticos e capacidade estimulatória para com as células T. Complementando estes dados, as ligações glicosídicas de ácidos siálicos criados por ST6Gal-1 e ST3Gal-1 são funcionalmente relevantes. A modulação programada da sialilação do glicocálice, mediada por sialidases individuais ou sialiltransferases é uma possibilidade aceitável para a melhoria da fagocitose por DCs e da sua potência imunológica. Este facto tem um significado particular para imunoterapias baseadas em DCs, podendo provar-se decisivo para a sua eficiência e aplicabilidade num futuro muito próximo.-------------------------------ABSTRACT: Glycans decorating cell surface and secreted proteins and lipids occupy the junction where critical host–host and host-pathogen interactions occur. In spite of the wide acceptance that glycans are centrally implicated in immunity, exactly how glycans and their variety and variability contribute to the overall immune response remains poorly defined. Glycans, frequently terminated by sialic acid residues, may be modified by external factors such as pathogens or upon specific physiological cellular events. The terminal, privileged positions of sialic acid-modified structures makes them key, fundamental determinants for a number of immune receptors with known involvement in cellular adhesiveness and cell trafficking, such as Selectins and Siglecs, with known relevant immune functions. At the time this thesis was initiated, it was established that sialic acids expressed at cell surface could modulate important mechanisms of the adaptive immune responses. Given the key role of dendritic cells (DCs) in the transition from innate to the adaptive immune responses, we anticipated that sialic acids could also modulate important mechanisms of human DCs. DCs have a relevant role in antigen screening and uptake, migration to lymph nodes and antigen presentation to lymphocytes, ultimately triggering the adaptive immune response. Therefore, our primary hypothesis was that sialic acids may modulate DC functions, such as antigen uptake, maturation, homing to lymph nodes and antigen presentation to T cells. To test this hypothesis, we divided our work in four parts. 1) Surface sialylated glycans expressed during differentiation from human monocytes to DCs (moDCs) were analyzed. Our data showed that α2,3-sialylated O-glycans and α2,6- and α2,3-sialylated N-glycans expression increased during moDC differentiation. Three main sialyltransferases (STs) are committed with this new glycan configuration: ST6Gal- 1 correlates with the increased expression of α2,6-sialylated N-glycans; ST3Gal-1 32 contributes for the α2,3-sialylation of O-glycans, especially T antigens; and ST3Gal-4 may contribute for the increased α2,3-sialylated N-glycans. Upon moDC maturation, ST6Gal-1 and ST3Gal-4 are downregulated and ST3Gal-1 is altered in a stimulus dependent manner. 2) We subsequently analyzed the consequences of the modulation of cell surface sialic acids in DC functions. We observed that removing surface sialic acid by sialidase significantly decreased the capacity of moDCs to micropinocytose and receptormediated endocytose. In contrast, treatment with a sialidase significantly improved the capacity of moDCs to phagocytose Escherichia coli. The improved phagocytosis mechanism required E. coli sialic acids, indicating a mechanism of host–pathogen interaction dependent on sialic acid moieties. Sialidase-treated moDCs have increased expression of MHC and co-stimulatory molecules, suggesting a more mature phenotype. Experiments using mouse bone marrow-derived DCs (BMDCs) from ST3Gal-1-/- and ST6Gal-1-/- strains indicated that endocytosis and maturation are influenced by changes in either α2,3 or α2,6-sialylated glycans. The analysis of α2,6-sialylated, N-glycosylated proteins, strongly suggested the potential involvement of β2 integrins, underlying these mechanisms. 3) The effect of α2,6-sialylation in DC homing to lymph nodes was also analyzed. We observed that BMDCs deficient for ST6Gal-1 have an almost 50% reduction in DC homing, as assayed by in situ inflammation and adoptive transfer studies. A reduction in DC homing was also observed when wild type BMDCs were transferred into ST6Gal-1-/- recipient mice. Further investigations are necessary to identify the molecules involved in this process. 4) Finally, we also analyzed the impact of sialylation on DCs ability to prime T cells. Sialidase-treated moDCs show increased gene expression of IL-12, TNF-α, IL-6 and IL- 10 cytokines, and activation of the transcription factor nuclear factor-κB. Sialidase33 treated DCs induced a higher proliferative response of T cells with concomitant higher expression of interferon-γ, suggesting that the clearance of cell surface sialic acids contributes to the development of a T helper type 1 proinflammatory response. Together, our data strongly support sialic acid’s relevance in DC immune functions. Alterations of cell surface sialic acid content can alter the endocytosis/phagocytosis, maturation, migration/homing and the ability for T cell priming in human DCs. Moreover, sialic acid linkages created by ST6Gal-1 and ST3Gal-1 are functionally relevant. The engineering of cell surface sialylation, mediated by individual sialidases or sialyltransferases is a likely possibility to fine tune DC phagocytosis and immunological potency, with particular significance to DC-based therapies.
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The monitoring data collected during tunnel excavation can be used in inverse analysis procedures in order to identify more realistic geomechanical parameters that can increase the knowledge about the interested formations. These more realistic parameters can be used in real time to adapt the project to the real structure in situ behaviour. However, monitoring plans are normally designed for safety assessment and not especially for the purpose of inverse analysis. In fact, there is a lack of knowledge about what types and quantity of measurements are needed to succeed in identifying the parameters of interest. Also, the optimisation algorithm chosen for the identification procedure may be important for this matter. In this work, this problem is addressed using a theoretical case with which a thorough parametric study was carried out using two optimisation algorithms based on different calculation paradigms, namely a conventional gradient-based algorithm and an evolution strategy algorithm. Calculations were carried for different sets of parameters to identify several combinations of types and amount of monitoring data. The results clearly show the high importance of the available monitoring data and the chosen algorithm for the success rate of the inverse analysis process.
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A Gß protein and the TupA Co-Regulator Bind to Protein Kinase A Tpk2 to Act as Antagonistic Molecular Switches of Fungal Morphological Changes
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Synthesis gas, a mixture of CO, H2, and CO2, is a promising renewable feedstock for bio-based production of organic chemicals. Production of medium-chain fatty acids can be performed via chain elongation, utilizing acetate and ethanol as main substrates. Acetate and ethanol are main products of syngas fermentation by acetogens. Therefore, syngas can be indirectly used as a substrate for the chain elongation process.