Academic literature on the topic 'Influenza A M2e'
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Journal articles on the topic "Influenza A M2e"
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Tan, Mei Peng, Noorjahan Banu Mohamed Alitheen, Wen Siang Tan, and Wei Boon Yap. "Expression of Influenza M2e-NP Recombinant Fusion Protein in Escherichia coli BL21 (DE3) and Its Binding to Antibodies." Vaccines 10, no. 12 (2022): 2066. http://dx.doi.org/10.3390/vaccines10122066.
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The current influenza vaccines only confer protection against the circulating influenza subtypes, therefore universal vaccines are needed to prevent upcoming influenza outbreaks caused by emerging influenza subtypes. The extracellular domain of influenza A M2 protein (M2e) is highly conserved among different subtypes of influenza A viruses, and it is able to elicit protective immunity against the viruses. The influenza nucleoprotein (NP) was used to display the M2e in this study due to its promising T-cell response and adjuvanticity. The M2e gene was fused to the 5′-end of the NP gene and then cloned into pRSET B vector. The DNA sequencing analysis revealed six point mutations in the M2e-NP fusion gene, including one mutation in the M2e peptide and five mutations in the NP. The mutations were reverted using PCR site-directed mutagenesis. The recombinant plasmids (pRSET B-M2e-NP and pRSET B-mM2e-NP) were introduced into Escherichia coli (E. coli) BL21 (DE3) for protein expression. The mutated and non-mutated proteins were subsequently expressed and named mM2e-NP and M2e-NP, respectively. The expression of mM2e-NP and M2e-NP was not affected by the mutations. The binding of anti-M2e antibody to the purified native mM2e-NP and M2e-NP also remained active. However, when the anti-NP antibody was tested, the signal produced by mM2e-NP was very weak. The results implied that the amino acid changes in the NP had adversely impacted on the conformation of mM2e-NP and subsequently affected the antibody binding. In light of the remarkable antibody binding to the M2e-NP fusion protein, this study highly recommends the potential of M2e-NP as a universal influenza vaccine candidate.
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Cho, Ki Joon, Bert Schepens, Jong Hyeon Seok, et al. "Structure of the Extracellular Domain of Matrix Protein 2 of Influenza A Virus in Complex with a Protective Monoclonal Antibody." Journal of Virology 89, no. 7 (2015): 3700–3711. http://dx.doi.org/10.1128/jvi.02576-14.
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ABSTRACTThe extracellular domain of influenza A virus matrix protein 2 (M2e) is conserved and is being evaluated as a quasiuniversal influenza A vaccine candidate. We describe the crystal structure at 1.6 Å resolution of M2e in complex with the Fab fragment of an M2e-specific monoclonal antibody that protects against influenza A virus challenge. This antibody binds M2 expressed on the surfaces of cells infected with influenza A virus. Five out of six complementary determining regions interact with M2e, and three highly conserved M2e residues are critical for this interaction. In this complex, M2e adopts a compact U-shaped conformation stabilized in the center by the highly conserved tryptophan residue in M2e. This is the first description of the three-dimensional structure of M2e.IMPORTANCEM2e of influenza A is under investigation as a universal influenza A vaccine, but its three-dimensional structure is unknown. We describe the structure of M2e stabilized with an M2e-specific monoclonal antibody that recognizes natural M2. We found that the conserved tryptophan is positioned in the center of the U-shaped structure of M2e and stabilizes its conformation. The structure also explains why previously reportedin vivoescape viruses, selected with a similar monoclonal antibody, carried proline residue substitutions at position 10 in M2.
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Reese, Kaleb A., Christopher Lupfer, Rudd C. Johnson, et al. "A Novel Lactococcal Vaccine Expressing a Peptide from the M2 Antigen of H5N2 Highly Pathogenic Avian Influenza A Virus Prolongs Survival of Vaccinated Chickens." Veterinary Medicine International 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/316926.
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A cost-effective and efficacious influenza vaccine for use in commercial poultry farms would help protect against avian influenza outbreaks. Current influenza vaccines for poultry are expensive and subtype specific, and therefore there is an urgent need to develop a universal avian influenza vaccine. We have constructed a live bacterial vaccine against avian influenza by expressing a conserved peptide from the ectodomain of M2 antigen (M2e) on the surface ofLactococcus lactis(LL). Chickens were vaccinated intranasally with the lactococcal vaccine (LL-M2e) or subcutaneously with keyhole-limpet-hemocyanin conjugated M2e (KLH-M2e). Vaccinated and nonvaccinated birds were challenged with high pathogenic avian influenza virus A subtype H5N2. Birds vaccinated with LL-M2e or KLH-M2e had median survival times of 5.5 and 6.0 days, respectively, which were significantly longer than non-vaccinated birds (3.5 days). Birds vaccinated subcutaneously with KLH-M2e had a lower mean viral burden than either of the other two groups. However, there was a significant correlation between the time of survival and M2e-specific serum IgG. The results of these trials show that birds in both vaccinated groups had significantly (P<0.05) higher median survival times than non-vaccinated birds and that this protection could be due to M2e-specific serum IgG.
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Ingrole, Rohan S., Wenqian Tao, Jatindra N. Tripathy, and Harvinder S. Gill. "Synthesis and Immunogenicity Assessment of Elastin-Like Polypeptide-M2e Construct as an Influenza Antigen." Nano LIFE 04, no. 02 (2014): 1450004. http://dx.doi.org/10.1142/s1793984414500044.
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The 23 amino acid-long extracellular domain of the influenza virus transmembrane protein M2 (M2e) has remained highly conserved since the 1918 pandemic, and is thus considered a good candidate for development of a universal influenza A vaccine. However, M2e is poorly immunogenic. In this study we assessed the potential of increasing immunogenicity of M2e by constructing a nanoscale-designed protein polymer containing the M2e sequence and an elastin-like polypeptide (ELP) nanodomain consisting of alanine and tyrosine guest residues (ELP(A2YA2)24). The ELP nanodomain was included to increase antigen size, and to exploit the inherent thermal inverse phase transition behavior of ELPs to purify the protein polymer. The ELP(A2YA2)24 + M2e nanodomained molecule was recombinantly synthesized. Characterization of its inverse phase transition behavior demonstrated that attachment of M2e to ELP(A2YA2)24 increased its transition temperature compared to ELP(A2YA2)24. Using a dot blot test we determined that M2e conjugated to ELP is recognizable by M2e-specific antibodies, suggesting that the conjugation process does not adversely affect the immunogenic property of M2e. Further, upon vaccinating mice with ELP(A2YA2)24 + M2e it was found that indeed the nanodomained protein enhanced M2e-specific antibodies in mouse serum compared to free M2e peptide and ELP(A2YA2)24. The immune serum could also recognize M2 expressed on influenza virions. Overall, this data suggests the potential of using molecules containing M2e-ELP nanodomains to develop a universal influenza vaccine.
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Zhang, Yi-Nan, Keegan Braz Gomes, Yi-Zong Lee, et al. "A Single-Component Multilayered Self-Assembling Protein Nanoparticle Vaccine Based on Extracellular Domains of Matrix Protein 2 against Both Influenza A and B." Vaccines 12, no. 9 (2024): 975. http://dx.doi.org/10.3390/vaccines12090975.
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The development of an effective and broadly protective influenza vaccine against circulating and emerging strains remains elusive. In this study, we evaluated a potentially universal influenza vaccine based on single-component self-assembling protein nanoparticles (1c-SApNPs) presenting the conserved matrix protein 2 ectodomain (M2e) from influenza A and B viruses (IAV and IBV, respectively). We previously designed a tandem antigen comprising three IAV M2e domains of human, avian/swine, and human/swine origins (termed M2ex3). The M2ex3-presenting 1c-SApNPs conferred complete protection in mice against sequential lethal challenges with H1N1 and H3N2. To broaden this protection to cover IBVs, we designed a series of antigens incorporating different arrangements of three IAV M2e domains and three copies of IBV M2e. Tandem repeats of IAV and IBV (termed influenza A-B) M2e arrayed on the I3-01v9a 60-mer 1c-SApNP, when formulated with an oil-in-water emulsion adjuvant, generated greater M2e-specific immunogenicity and protective efficacy than the soluble influenza A-B M2e trimer, indicated by higher survival rates and reduced weight loss post-challenge. Importantly, one of the influenza A-B M2e SApNP constructs elicited 100% protection against a lethal influenza A/Puerto Rico/8/1934 (H1N1) challenge in mice and 70% protection against a lethal influenza B/Florida/4/2006 (Yamagata lineage) challenge, the latter of which has not been reported in the literature to date. Our study thus provides a promising M2e-based single-component universal vaccine candidate against the two major types of influenza virus circulating in humans.
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Kim, Ki-Hye, Zhuo Li, Noopur Bhatnagar, et al. "Universal protection against influenza viruses by multi-subtype neuraminidase and M2 ectodomain virus-like particle." PLOS Pathogens 18, no. 8 (2022): e1010755. http://dx.doi.org/10.1371/journal.ppat.1010755.
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Annual influenza vaccination is recommended to update the variable hemagglutinin antigens. Here, we first designed a virus-like particle (VLP) displaying consensus multi-neuraminidase (NA) subtypes (cN1, cN2, B cNA) and M2 ectodomain (M2e) tandem repeat (m-cNA-M2e VLP). Vaccination of mice with m-cNA-M2e VLP induced broad NA inhibition (NAI), and M2e antibodies as well as interferon-gamma secreting T cell responses. Mice vaccinated with m-cNA-M2e VLP were protected against influenza A (H1N1, H5N1, H3N2, H9N2, H7N9) and influenza B (Yamagata and Victoria lineage) viruses containing substantial antigenic variations. Protective immune contributors include cellular and humoral immunity as well as antibody-dependent cellular cytotoxicity. Furthermore, comparable cross protection by m-cNA-M2e VLP vaccination was induced in aged mice. This study supports a novel strategy of developing a universal vaccine against influenza A and B viruses potentially in both young and aged populations by inducing multi-NA subtype and M2e immunity with a single VLP entity.
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Kang, Sang-Moo, Ki-Hye Kim, Jeeva Subbiah, et al. "Non-neutralizing immune-mediated cross-protection against influenza viruses by chimeric M2e-H3 stalk protein or multi-subtype neuraminidase plus M2e virus-like particle vaccine in ferrets." Journal of Immunology 212, no. 1_Supplement (2024): 0099_5226. http://dx.doi.org/10.4049/jimmunol.212.supp.0099.5226.
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Abstract Current influenza vaccine based on hemagglutinin (HA) immunity is not effective in providing cross protection against circulating variants and new pandemic viruses. In prior studies, we developed universal influenza vaccine candidates of multi-subtype neuraminidase and M2 ectodomain virus-like particles (m-cNA-M2e VLP) and chimeric M2e-H3 stalk protein vaccine (M2e-H3stalk), which were effective in inducing cross-protective immunity in mice. Here, we evaluated the immunogenicity and efficacy of these recombinant universal influenza vaccines in ferrets. Our results showed that immunization of ferrets with recombinant universal vaccines induced high levels of IgG antibody responses (M2e, H3stalk, multi-subtype NA), NA inhibition (NAI), antibody-secreting plasma cells in spleens, and IFN-γ secreting blood mononucleate cells. Ferrets with either m-cNA-M2e VLP or M2e-H3stalk vaccine were moderately protected from H1N1 and H3N2 influenza viruses as evidenced by lower viral titers in nasal washes, trachea and lung after challenge. Tests of passive immunity of vaccinated ferret antisera indicate that multi-NA plus M2e vaccine conferred more effective and broader humoral immunity in naïve mice than M2e-H3stalk vaccine. Our findings support that immunity to M2e, HA-stalk, and multi subtypes NA will induce broader cross protection in ferrets, which is likely translational to humans.
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Zharikova, Darya, Krystyna Mozdzanowska, Jingqi Feng, Manxin Zhang, and Walter Gerhard. "Influenza Type A Virus Escape Mutants Emerge In Vivo in the Presence of Antibodies to the Ectodomain of Matrix Protein 2." Journal of Virology 79, no. 11 (2005): 6644–54. http://dx.doi.org/10.1128/jvi.79.11.6644-6654.2005.
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ABSTRACT The ectodomain of matrix protein 2 (M2e) of human influenza type A virus strains has remained remarkably conserved since 1918. Because M2e-specific immunity has been shown to decrease morbidity and mortality associated with influenza virus infection in several animal models and because natural infection and current vaccines do not appear to induce a good M2e-specific antibody (Ab) response, M2e has been considered as potential vaccine for inducing cross-reactive protection against influenza type A viruses. The high degree of structural conservation of M2e could in part be the consequence of a poor M2e-specific Ab response and thus the absence of pressure for change. To assess this possibility, we studied the course of infection in SCID mice in the presence or absence of passive M2e-specific monoclonal Abs (MAbs). We found that virus mutants with antigenic changes in M2e emerged in 65% of virus-infected mice treated with M2e-specific but not control MAbs. However, the diversity of escape mutants was highly restricted since only two types were isolated from 22 mice, one with a proline-to-leucine and the other with a proline-to-histidine interchange at amino acid position 10 of M2e. The implications of these findings for the use of M2e as a broadly protective vaccine are discussed.
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Callejo, Bernadette, Tom Monath, Marla Lay, Stella Chang, and Jeff Fairman. "Highly Immunogenic JVRS-100 Adjuvanted Universal Influenza A Vaccine (52.4)." Journal of Immunology 184, no. 1_Supplement (2010): 52.4. http://dx.doi.org/10.4049/jimmunol.184.supp.52.4.
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Abstract A vaccine based on a conserved external ectodomain of M2 (M2e) offers the potential for inducing broad-immunity against divergent influenza A strains including pandemic viruses. Cohorts of mice were vaccinated 3x (IM) with M2e in the form of a multiple antigenic peptide with 4 copies of M2e (MAP4), with or without cationic lipid DNA complex adjuvant (JVRS-100). Lethal challenge using different strains of virus (H1N1, H3N2) were done to establish efficacy based on survival. The addition of JVRS-100 to M2e-MAP4 resulted in a significant decrease in morbidity and mortality following lethal challenge with H1N1 (survival 100% vs. 30% without adjuvant) or H3N2 (80% vs. 20%). Adjuvanted vaccine resulted in higher levels of IgG (p=0.0159), IgG1 (p&lt;0.02) and IgG2a (p&lt;0.005) vs. M2e-MAP4 alone. A dose titration of M2e-MAP4 inoculated with a constant amount of JVRS-100 resulted in 100% survival after challenge even at a vaccine dose of 25ng. Addition of M2e-MAP4/JVRS-100 to trivalent inactivated influenza vaccine (TIV) confers full protection with a single vaccination prior to lethal challenge. Competitive binding ELISA confirmed that the sera from vaccinated mice contained M2e conformational epitopes. Vaccination with MAP2 and MAP4 indicated the protective epitopes were dependent on dimeric and not tetrameric configuration of the MAP construct. The experiments demonstrate the potency of MAP configured M2e peptide with the JVRS-100 adjuvant in the development of universal flu vaccine.
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Heinen, Paul P., Frans A. Rijsewijk, Els A. de Boer-Luijtze, and André T. J. Bianchi. "Vaccination of pigs with a DNA construct expressing an influenza virus M2–nucleoprotein fusion protein exacerbates disease after challenge with influenza A virus." Journal of General Virology 83, no. 8 (2002): 1851–59. http://dx.doi.org/10.1099/0022-1317-83-8-1851.
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In mice, vaccines inducing antibodies to the extracellular domain of the M2 protein (M2e) can confer protection to influenza A virus infection. Unlike the surface glycoproteins, haemagglutinin and neuraminidase, this domain of M2 is highly conserved and is therefore a potential broad-spectrum immunogen. In this study, the protection conferred by vaccines inducing antibodies to M2e was evaluated in a challenge model for swine influenza in pigs. A protein resulting from the fusion between M2e and the hepatitis B virus core protein (M2eHBc), with or without adjuvant, was evaluated. In addition, a DNA construct expressing a fusion protein between M2e and influenza virus nucleoprotein (M2eNP) was evaluated to see if the broad-spectrum protection conferred by antibodies could be further enhanced by T helper cells and cytotoxic T cells. All vaccines induced an antibody response against M2e, and the M2eNP DNA vaccine additionally induced an influenza virus-specific lymphoproliferation response. However, after challenge with a swine influenza virus (H1N1), no protection was observed in the vaccinated groups compared with the non-vaccinated control group. On the contrary, vaccinated pigs showed more severe clinical signs than the control pigs. The M2eNP DNA-vaccinated pigs showed the most severe clinical signs and three out of six pigs died on days 1 and 2 post-challenge. These results indicate that antibodies to M2e, especially in combination with cell-mediated immune responses, exacerbate disease. Thus, clinical signs after infection should be observed closely in further studies using M2e as an immunogen and caution should be exercised in using M2e in humans.
Dissertations / Theses on the topic "Influenza A M2e"
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Leung, Ho-chuen, and 梁浩銓. "A study of H5N1-M2e-based universal influenza vaccine." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208568.
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The ectodomain of influenza matrix protein 2 (M2e) may be an ideal candidate in the development of influenza universal vaccine due to its highly conserved property among different subtypes/strains of influenza virus. M2e based vaccines have been extensively studied and potent cross-subtype/strain protections have been reported. However, more and more M2e mutants of influenza virus have been identified in recent years. It is still unclear whether M2e based vaccines are effective against these M2e mutants of influenza virus.
This study first evaluated cross-protection of an M2e tetrameric peptide vaccine based on H5N1 virus strain A/Vietnam/1194/04 (VN/1194-M2e) against lethal challenges of M2e mutants of H5N1 virus strain A/Hong Kong/156/97 (HK/156) and a novel H7N9 virus, because there are 3 or 5 amino acid differences between VN/1194-M2e and HK/156-M2e or VN/1194-M2e and H7N9-M2e. The results showed that the vaccination of VN/1194-M2e did not induce high level of cross-reactive antibodies against HK/156-M2e and just provided poor cross-protection against lethal challenge of HK/156 virus. In contrast, VN/1194-M2e vaccination induced high level of cross-reactive antibodies against H7N9-M2e. Consistently, the vaccination provided good cross-protection against lethal challenge of H7N9 virus. These results strongly suggested that some mutations in M2e, such as mutations at positions 10, 14 and 16 which found in HK/156 M2e, might affect the M2e vaccine efficacy, but some others, such as five mutations found in H7N9-M2e, might not be critical for the M2e immunogenicity.
This study then investigated the relationship between the M2e immunogenicity and amino acid mutations of the M2e. Beside VN/1194-M2e (P0), we synthesized additional 10 M2e mutant peptides which contain different single or multiple mutations. The 3D structures of these M2e peptides were predicted and analyzed. The prediction results showed that group 1 peptides (P0, P10, P14, P16, P18, P20 and P18-20) exhibited either irregular structures or loose hairpin structures which might associate with well exposure of antigenic epitope, whereas group 2 peptides (P10-14, P10-16, P14-16 and P10-14-16) formed tight hairpin structures in which antigenic epitope might bury inside their own secondary structure. Vaccination efficacies of these M2e peptides were evaluated in mice for antibody responses and cross-protection against lethal challenge of VN/1194 and HK/156 viruses. Our results showed that vaccinations of group 1 peptides induced high levels of cross-reactive antibodies against VN/1194-M2e and good cross-protection against lethal challenge of VN/1194 virus. However, vaccinations of group 2 peptides vaccinations induced significantly lower VN/1194-M2e antibody responses and poor cross-protection against lethal challenge of VN/119 virus. Furthermore, both group 1 and group 2 peptides could just induce low levels of cross-reactive antibodies against HK/156-M2e and poor protection against lethal challenge of HK/156 virus.
Although H5N1-M2e tetrameric peptide has been previously shown to protect mice from lethal challenges by different subtypes/strains of influenza virus, this study has shown that certain amino acid variations in M2e could weaken M2e immunogenicity but some others might not. The different secondary structures of M2es may probably associate with their immunogenicity. Our findings have provided valuable information for the development of M2e based universal vaccines.<br>published_or_final_version<br>Microbiology<br>Doctoral<br>Doctor of Philosophy
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Khan, Tila. "Tailored influenza virus vaccines for both the young and old: Vaccine Efficacy of Whole Inactivated Vaccines bearing Immunomodulatory Adjuvants or Multimeric peptides." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77130.
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Influenza epidemics and pandemics remain a significant burden to world health and economy. Low efficacy of current inactivated influenza vaccines in the elderly and immunocompromized and the inability to protect against antigenically drifted or shifted strains of influenza virus are the two major problems in influenza vaccine research. To overcome these hurdles, we have utilized an in vitro cell culture vaccine platform, which results in whole inactivated influenza vaccine (WIV) bearing bioactive membrane-anchored immunomodulatory proteins such as cytokines on the virion surface, collectively known as CYT-IVACs (Cytokine bearing-Inactivated Vaccine). In addition, we tested whether a multimeric M2e peptide presented on WIV can serve to enhance immunogenicity and augment protective efficacy of whole virus vaccines. Our panel of cytokines includes IL-2, IL-4, IL-12, IL-23, and Flt3L as well as the multimeric M2e peptide, all fused to the membrane anchoring regions of influenza virus hemagglutinin protein and constitutively expressed in virus permissive MDCK cell line. Subsequent infection with influenza virus results in incorporation of fusion constructs directly into budding progeny virions that are harvested, purified and inactivated to generate distinct CYT-IVAC formulations. Following validation of immunomodulator incorporation, vaccines were tested for in vivo efficacy in either "young adult" or "aged" female Balb/c mice. Our results demonstrate that our CYT-IVAC~IL-12/HA and CYT-IVAC~IL-23/HA serve as potent mucosal adjuvants in young adult mice elicited significantly high levels of mucosal IgA antibodies and afford superior protection against lethal virus challenge. Our Flt3L/HA formulation was the most effective stimulator of systemic anti-viral antibody levels. In "aged" mice a single dose formulation of IL-12 bearing CYTIVAC was superior at affording protection against lethal homotypic virus challenge. Finally, administration of multimeric M2e molecule co-presented on WIV elicited prolonged antibody responses in "young adult mice" and provided cross-protection from challenge with the heterologous influenza A pandemic strain 2009 H1N1. In conclusion, the CYT-IVAC approach represents a novel tailored advancement to current WIV approaches that has the potential to elicit both potent mucosal and systemic immune responses in young and old.<br>Ph. D.
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Elaish, Mohamed Salaheldin Ahmed Nassif Elaish. "Development of universal Influenza vaccine in chicken with insights on the extracellular domain of Matrix protein 2." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1471877010.
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Sneyd, Hannah, and Hannah Sneyd. "Influenza A: Mechanism of Infection and Development of M2 Ion Channel Inhibitors." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/626385.
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Influenza viral infection causes several hospitalizations and claims the lives of many people each year. The threat of epidemic and pandemic are more pressing than ever with newly mutated strains developing every year. Understanding the mechanism of infection of influenza can help identify new potential drug targets and help progress the development of antivirals. Currently there are two classes of FDA approved drugs, neuraminidase inhibitors and M2 ion channel inhibitors, to combat influenza infection. Unfortunately, viral resistance to M2 ion channel blockers has caused them to stop being used for treatment. This paper focuses on understanding influenzas ability to mutate and it mechanism of infection to develop new M2 ion channel blockers.
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Duff, Kevin Campbell. "Biophysical studies on influenza A M2 protein." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/19707.
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The influenza A M2 protein and, in particular, the proposed transmembrane domain, has been implicated in viral infectivity at two stges in the replicative cycle: viral uncoating and assembly. An identical function has been proposed for the protein at both points of interest, that is, that M2 acts as a proton channel. In order to work, this hypothesis assumes that M2 possesses a transmembrane domain, presumably in a α-helical conformation, that this domain orientates in a prescribed manner across the bilayer and that, indeed, M2 is able to translocate protons across the aforementioned bilayer. This thesis examines these assumptions experimentally using a synthetic, 25 amino acid peptide representing the proposed transmembrane domain of M2. The work described herein may be divided into three main areas, each employing a separate biophysical technique. Circular dichroism was employed to assign an α-helical secondary structure to the M2 peptide. Neutron diffraction orientated this region precisely in the bilayer. Electrophysiological techniques observed directly, for the first time in viruses, proton translocation. The effects of amantadine, the only drug prescribed for use against influenza A infections, in each of these structural asnd functional investigations has also been recorded, providing revealing insights into the drug's efficacy. M2 has structural analogs in other enveloped viruses and work such as that reported in this thesis may reveal a common pathway of viral infectivity for groups of enveloped viruses, therefore allowing the possibility of broad-spectrum drug therapies.
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Hayhurst, Andrew. "Studies on the influenza A virus M2 protein." Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250090.
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Carpenter, Timothy S. "Simulation studies of the influenza M2 channel protein." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504314.
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Ma, Huailiang, and 马怀良. "Identification of human annexin A6 as a novel cellular interactant of influenza A virus M2 protein and regulator of virus budding andrelease." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48521747.
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Influenza viruses exploit sophisticated host cell machinery to replicate, causing both seasonal epidemics and unpredictable pandemics. Studying the host cellular factors interacting with conserved domains of viral proteins will help us to identify key host proteins for the virus infection. This will not only strengthen our understanding of the precise mechanisms of the virus life cycle, but also pave new avenues for anti-viral development.
The cytoplasmic tail of M2 ion channel (M2/CT) is one of these highly conserved domains. It is fully accessible to the host cell machinery after fusion of the virus envelope with the endosomal membrane and during the trafficking, assembly, and budding processes. I hypothesized that recruitment of host cellular factors by M2/CT may regulate the M2-dependent stages of the virus life cycle. Through a large scale yeast two-hybrid (Y2H) screen with the M2/CT used as bait, the human annexin A6 was identified as a novel host cell interactant and this interaction was further confirmed by both GST pull-down assay on purified proteins and co-immunoprecipitation assay on virus infected cells.
A functional characterization of this novel interaction demonstrated that depletion of annexin A6 could enhance the virus production, while its overexpression could reduce the virus propagation, which indicates that annexin A6 is a negative regulator of the virus infection. However, I found that the virus infection could not induce any changes of annexin A6 expression. Therefore, the annexin A6-mediated regulation may depend on the subcellular localization where the interaction with M2/CT occurs. To decipher which step of the virus replication is regulated, we dissected the virus life cycle and found that modulation of annexin A6 expression had no effect on the early stages of the virus life cycle or on viral RNA replication but impaired the release of progeny virus, as suggested by delayed or defective budding events observed at the plasma membrane of virus-infected and annexin A6-overexpressing cells during a transmission electron microscopy study. To further decipher the underlying molecular mechanisms, the contribution of annexin A6-mediated plasma membrane lipid rafts reorganization through cholesterol homeostasis modulation and cortical actin cytoskeleton remodeling was also investigated.
In conclusion, here I have identified the human annexin A6 as a novel host cell interactant of M2/CT that negatively modulate the influenza virus infection by impairing the virus budding and release. This work further supports the idea that M2 is a multifunctional protein and is also consistent with the discovery by Rossman et al. that M2/CT mediates the virus budding process (Rossman et al., 2010). This study further emphasizes the importance of host cell interactants of M2/CT in this process. Regarding the biology of annexins, this study also adds a new member of this protein family in the list of regulators of influenza virus infection.<br>published_or_final_version<br>Public Health<br>Doctoral<br>Doctor of Philosophy
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Spearpoint, Philip Anthony. "Structure-function studies of the influenza A M2 proton channel." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1446119/.
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The influenza A virus M2 protein is a minor component of the virus membrane, it forms a homotetrameric, pH-activated, proton-selective channel and is the target of the anti-influenza drugs, amantadine and rimantadine. Two projects were undertaken to study the structure-function relationships of M2 and the mechanism of its inhibition. Firstly, an M2 protein with a pH-sensitive GFP fused to the C-terminus was constructed to determine whether it could be used to measure directly M2 proton conduction. The pH probe was responsive to rimantadine-sensitive changes in the pH gradient which were detected but were small. This was in part due to reduced proton conductance of the protein possibly due to altered conformation of the M2 pore, but may also reflect the low sensitivity of the GFP probe to local pH in the vicinity of the plasma membrane. Secondly tryptophan fluorescence studies of purified, E.coli- expressed M2 protein in detergent micelles investigated the mechanism of proton conduction and inhibition by anti-M2 drugs. Shifts in emission maxima and fluorescence intensity measurements relating to the tryptophans in the M2 pore indicated a molecular interaction between histidine 37 (His37) and tryptophan 41 (Trp41). pKa values from these experiments correlated with previously reported proton-mediated activation and permeation of the M2 channel. Acrylamide quenching showed that upon histidine protonation, Trp41 was more solvent accessible while polarisation measurements indicated a more restricted environment for Trp41 at low pH. Red-edge excitation measurements suggested a proteinaceous pore in which water molecules were highly immobile when the channel was closed, yet could freely reorientate upon channel activation. The M2 inhibitor rimantadine reversed these phenomena either fully or partially. Equilibrium and time-resolved measurements of this drug-induced reversal permitted the determination of both association and dissociation rate constants and the affinities of drug interaction with M2. These results provide further support for an allosteric mechanism of amantadine inhibition.
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Rosen, Julia von. "Le transfert culturel comme transformation de discours : Mme de Stae͏̈l interprète de l'esthétique kantienne." Caen, 2003. http://www.theses.fr/2003CAEN1371.
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L'objectif de la présente étude consiste à analyser l'exemple particulièrement intéressant d'un transfert culturel dans le cadre des relations franco-allemandes, à savoir l'interprétation de l'esthétique kantienne que donne Mme de Stae͏̈l dans son oeuvre critique principale, De l'Allemagne. Cette interprétation doit être - telle est la thèse essentielle sur laquelle se fonde la structure et l'approche méthodologique de l'étude - mise en relation avec les positions esthétiques, philosophiques et linguistiques de Mme de Stae͏̈l, afin que tous les aspects essentiels impliqués dans le processus spécifique du transfert culturel puissent être respectés et intégrés dans l'analyse. Le problème fondamental consiste à déterminer les "objets" précis du transfert et la manière dont Mme de Stae͏̈l intègre les éléments de la théorie esthétique de Kant, telle qu'elle est formulée dans la Critique de la faculté de juger, dans son propre discours dans De l'Allemagne. A cet effet, l'analyse est structurée en trois parties :1. Comparaison entre les positions esthétiques de Mme de Stae͏̈l et de Kant ; 2. Analyse des positions épistémologiques et linguistiques de Mme de Stae͏̈l et 3. Analyse détaillée du discours stae͏̈lien sur l'esthétique kantienne. Il s'avère que les positions esthétiques des deux auteurs se distinguent nettement quant à la fonction et au statut qu'ils attribuent à l'esthétique. Dans sa présentation de la théorie kantienne, Mme de Stae͏̈l produit une sorte d'amalgame entre ses propres idées, les idées d'autres auteurs et celles de Kant en les " assimilant ", " romantisant " et " platonisant ". En analysant les stratégies textuelles de Mme de Stae͏̈l dans le contexte de ses positions philosophiques et linguistiques, on peut conclure que l'auteur n'était pas consciente d'avoir modifié aussi fortement les idées du philosophe allemand. Il faut donc constater que le transfert culturel opéré par Mme de Stae͏̈l représente une transformation profonde des idées kantiennes.
Books on the topic "Influenza A M2e"
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Ravasi, Sofia. Leopardi et Mme de Staël. Centro nazionale di studi leopardiani, 1999.
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Molchanov, Vladimir Efimovich. "Estʹ pami͡atʹ obo mne--": Stikhi poėtov-belgorodt͡sev ob A.S. Pushkine. Konstanta, 2005.
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Popova, I. M. "Chuzhoe slovo" v tvorchestve E.I. Zami͡a︡tina: N.V. Gogolʹ, M.E. Saltykov-Shchedrin, F.M. Dostoevskiĭ. Tambovskiĭ gos. tekhn. universitet, 1997.
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Chuo Kikuu cha Dar es Salaam. Taasisi ya Uchunguzi wa Kiswahili, ed. Jawabu la Mwana Kupona: Mausiyo ya mke wa kisasa, na wasiya wa Mwana Kupona. Taasisi za Taaluma za Kiswahili, Chuo Kikuu cha Dar es Salaam, 2011.
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Islam, Roumeen. Le droit d'informer: Le ro le des me dias dans le de veloppement e conomique. De Boeck, 2005.
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Brune, Franc ʹois. De l'ide ologie, aujourd'hui: Analyses, parfois de sobligeantes, du "discours" me diatico-publicitaire ... Parangon, 2004.
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Rudolf, Blum. Kallimachos: The Alexandrian Library and the origins of bibliography. University of Wisconsin Press, 1991.
Find full textBook chapters on the topic "Influenza A M2e"
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Lipsey, Richard G. "Joseph Agassi, the M2T Seminar, and His Influence on My Work." In Encouraging Openness. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-57669-5_37.
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Feuerstein, Reuven, Yaacov Rand, and John E. Rynders. "The Influence of Mediated Learning." In Don’t Accept Me as I am. Springer US, 1988. http://dx.doi.org/10.1007/978-1-4899-6128-0_4.
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Wawro, A., L. T. Baczewski, P. Pankowski, et al. "Annealing Influence on Co Ultrathin Film Morphology in MBE Grown Co/Au Bilayers." In Scanning Probe Microscopy: Characterization, Nanofabrication and Device Application of Functional Materials. Springer Netherlands, 2005. http://dx.doi.org/10.1007/1-4020-3019-3_24.
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Leeflang, Micha. "The Saint Reinhold Altarpiece by Joos van Cleve and his Workshop: New Insights into Albrecht Dürer’s Influence on the Working Process." In Me Fecit. Brepols Publishers, 2006. http://dx.doi.org/10.1484/m.mef-eb.3.806.
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Francesio, L., P. Franzosi, S. Gennari, et al. "Influence of the Temperature on the Morphology and Crystal Quality of MBE Grown InAs/GaAs Heterostructures." In Heterostructure Epitaxy and Devices. Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0245-9_31.
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Polymeneas-Liontiris, Thanos. "36. Mapping the Influence." In Meta-Xenakis. Open Book Publishers, 2024. http://dx.doi.org/10.11647/obp.0390.38.
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Iannis Xenakis’s pioneering work has been extensively prolific and diverse. Exploring his compositional principles within the context of today’s computational capabilities, today’s state-of-the-art music technologies, and contemporary aesthetics may offer composers and performers the possibility to explore uncharted territories in their music creativity and music making. My latest free improvisation performances have been such kinds of explorations; they extensively rely on the use of Dynamic Stochastic Synthesis combined with real-time data feedback processes. I explore ways of influencing a Dynamic Stochastic Synthesis algorithm in SuperCollider (Gendy1) using its own audio signal. The audio signal either influences parameters of the Gendy1 Unit Generator itself or affects other parameters in the overall digital signal processing that the Gendy1 Unit Generator belongs to. To manage the contribution of the feedback in the process and to control other parameters of the stochastic distributions I use Machine Learning mapping and more specifically the program Wekinator. The combination of these processes offers a great variety of quite harsh, often unstable, and unpredictable spectra of tonal and noisy sounds that call for interaction and playfulness in the context of live improvised music. My essential argument, aside from the technical or aesthetical aspects of it, is that in my case Xenakis’s work has primarily influenced me in being musically curious, explorative, daring to try, daring to borrow processes from different practices, and daring to challenge aesthetics, concepts, techniques, and technologies.
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Santos, Filipe Duarte, Paulo Lopes Ferreira, and Jiesper Strandsbjerg Tristan Pedersen. "Climate Change and Sustainability." In Sustainable Development Goals Series. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-24888-7_6.
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AbstractThe chapter discusses the challenge of global climate change and its relationship with sustainability. Following a brief review of the origin, principal drivers and current situation of climate change, an analysis of recent developments in climate change ethics and climate justice and their influence on climate change global policies is presented. We argue that the heterogeneous global climate movement has captured the world’s attention and will probably influence the future course of events. Finally, the chapter addresses the essential role of climate change action in achieving global sustainability and focuses on the interdependency between global inequalities and economic growth. The compatibility of mainstream neoclassical economics (MNE) with the rapid mitigation needed to reach the Paris Agreement temperature goals is discussed. Although far from optimal MNE mitigation policies, world climate change policies are strongly influenced by the global dominance of neoclassical economics.
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Wolter, Brent. "Chapter 9. Cross-language influences in the acquisition of L2 multiword expressions." In Cross-language Influences in Bilingual Processing and Second Language Acquisition. John Benjamins Publishing Company, 2023. http://dx.doi.org/10.1075/bpa.16.09wol.
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As with all aspects of L2 acquisition, the L1 has a marked influence on the acquisition of multiword expressions (MWEs). However, providing a unified framework to explain the L1’s influence on the acquisition of MWEs is challenging, particularly because MWEs vary in a number of ways. In this chapter, I begin by discussing various types of MWEs and how these can affect acquisition. I then move on to review research to date documenting the L1’s influence on L2 MWE acquisition before considering additional factors that have been shown to alter the effects of the L1. I conclude by calling for a holistic account of the acquisition of L2 MWEs that incorporates the influence of the L1 and other additional factors.
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Zude, Manuela, Alvin Alexander, and Peter Lüdders. "Influence of boron spray on boron concentration, fruit set and calcium related disorders in apple (Malus domestica) cv. ‘Elstar’/M26." In Boron in Soils and Plants. Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5564-9_27.
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Kurahara, Yoko, and Norihiro Itsubo. "Quantitative Environmental Impact Assessment for Agricultural Products Caused by Exposure of Artificial Light at Night." In Towards a Sustainable Future - Life Cycle Management. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-77127-0_3.
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AbstractIncrease in artificial lighting at night adversely affects human activities, wild animals, plants, agricultural crops, and livestock. The Ministry of the Environment defines such adverse effects as “light pollution.” Rice is an agricultural crop subject to the influence of light environment. We used LED lighting rice plants (“Koshihikari” cultivar) grown in a paddy field owned by professional farmers for illumination during the night and evaluated its impact on the rice’s heading and yield by actual measurement. We also factored in the roadway light installed in the paddy field’s vicinity and evaluated its effects on yield. Damage coefficients of light pollution for rice cultivation were developed, 18.9 g/m2/lx (equivalent to 0.046 US$/m2/lx) for natural white lighting and 16.4 g/m2/lx (equivalent to 0.039 US$ /m2/lx) for light bulb-colored lighting.
Conference papers on the topic "Influenza A M2e"
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Haniszewski, Tomasz, Jerzy Margielewicz, Slawomir Bucki, and Damian Gąska. "The Influence of Approximating the Mechanical Characteristics of a Hyperelastic Vibration Amplifier on Its Dynamic Properties." In 2024 21st International Conference on Mechatronics - Mechatronika (ME). IEEE, 2024. https://doi.org/10.1109/me61309.2024.10789702.
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Potanko, Andrej, Adam Jelinek, Tomas Marek, Ales Polzer, Libor Zak, and Michal Holub. "Case Study of the Influence of Linearity Uncertainty on the Applicability and Capability of CNC Machine Tools." In 2024 21st International Conference on Mechatronics - Mechatronika (ME). IEEE, 2024. https://doi.org/10.1109/me61309.2024.10789662.
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Lynh, Duong Huyen, and Tran Hai Nam. "Empowering Die Selection in V-Bending: Insights from Decision Tree Algorithms." In 2024 International Conference on Machining, Materials and Mechanical Technologies. Trans Tech Publications Ltd, 2025. https://doi.org/10.4028/p-epv4bq.
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This study presents the application of tree-based algorithms to predict springback in the V-bending process of sheet metals, particularly for SUS304 material. V-bending, a critical process in metal forming, often faces challenges due to springback, which affects dimensional accuracy and product quality. Using virtual experiments conducted via ANSYS software, the study evaluates the influence of variables such as die angle, die radius, material thickness, and punch displacement on springback. Four tree-based algorithms—Decision Trees, Random Forest, Gradient Boosting Machines (GBM), and Extra Trees—were used to predict springback, with the Decision Tree model showing the highest accuracy (Mean Absolute Error MAE=0.35; Mean Square Error=0.20). The findings indicate that incorporating predictive models into die and punch displacement selection can enhance operational efficiency and ensure consistent product quality. This methodology offers a cost-effective and efficient approach to improving the precision of sheet metal V-bending processes, with potential applications across various sheet metal materials.
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Achyar, Afifatul, Tati Kristianti, and Sony Suhandono. "Fusion Strategy of Influenza A-H5N1 Virus M2e Epitope DNA Sequence to Hepatitis B Virus HBsAg-S Gene." In International Conference on Biology, Sciences and Education (ICoBioSE 2019). Atlantis Press, 2020. http://dx.doi.org/10.2991/absr.k.200807.067.
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Oliveira Junior, Adair da Silva, Marcio Carneiro Brito Pache, Fábio Prestes Cesar Rezende, et al. "An Investigation of Parameter Optimization in Fingerling Counting Problems." In Workshop de Visão Computacional. Sociedade Brasileira de Computação - SBC, 2021. http://dx.doi.org/10.5753/wvc.2021.18881.
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The objective of this paper is to investigate which combination of parameters for the fingerling counting software results in the smallest Mean Absolute Error (MAE) and smallest Root Mean Squared Error (RMSE). For this, an image dataset called FISHCV155V was created and separated into training and test sets, where different combinations of parameters for the software were tested. From the obtained results were extracted individual performance metrics for each combination of parameters, such as MAE, Mean Square Error (MSE) and RMSE. Video frames were analysed comparing the parameter combination that obtained the best and worst results, in order to investigate the influence of such parameters in the performance of the software. From such results, it was concluded that the best combination reached 5.99 MAE and 9.96 RMSE.
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Silva, Larissa De Souza Da, and Matheus Souza Da Silva. "PERFIL ETIOLÓGICO DOS CASOS DE MENINGITE NO PARÁ ENTRE 2010-2020." In I Congresso Brasileiro de Doenças Infectocontagiosas On-line. Revista Multidisciplinar em Saúde, 2021. http://dx.doi.org/10.51161/rems/2245.
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Introdução: A meningite é uma doença infecciosa caracterizada pela inflamação das meninges, membranas que envolvem o sistema nervoso. Das ocorrências de meningite no Brasil, a mais grave é a bacteriana que tem como agentes etiológicos principais, bactérias meningocócicas e pneumocócicas. No Sistema Único de Saúde (SUS) é ofertada a vacina contra o Haemophilus influenzae sorotipo B o que representa uma medida eficaz no combate aos casos da doença. No entanto, os casos diagnosticados são graves, representam um desafio no tratamento e podem evoluir para o óbito dos indivíduos. Objetivos: Investigar o cenário epidemiológico referente a etiologia da meningite no Brasil entre 2010 e 2020. Metodologia: O presente trabalho trata-se de um estudo do tipo ecológico, de abordagem quantitativa, caráter descritivo e retrospectivo realizada no espaço temporal de 2010 a 2020 com base nos dados obtidos através do Departamento de Informática do SUS (DATASUS) disponibilizados pelo Ministério da Saúde. Resultados: Entre os anos de 2010 e 2020 obteve-se um total de 4.424 casos de meningite no estado do Pará, desse total 1.290 casos são causados por Meningite Viral (MV) seguido por 1.099 casos causados por Meningite Bacteriana (MB), 655 casos causados por Meningite Não Especificada (MNE) e 439 casos causados por Meningite por outras etiologias (MOE). Os anos de 2017 e 2018, foram os anos com maior número de casos totalizando 506 e 515 casos, respectivamente. Desse total 179 foram causados por MV, seguido de 107 casos causados por MB, 73 por MNE e 41 por MOE; e em 2018 foram 126 casos causados por MV, 133 por MB, 82 por MNE e 45 por MOE. Conclusão: O acompanhamento do perfil etiológico da meningite deve ser considerado durante o diagnóstico, visto o melhor prognóstico dos indivíduos quando submetidos ao tratamento adequado para cada perfil da doença. Além disso, ressalta-se a importância do diagnóstico em tempo hábil e considerando-se o perfil epidemiológico dos indivíduos para que isso possibilite um melhor direcionamento das políticas de saúde pelas entidades governamentais, especialmente no que diz respeito aos neonatos e crianças, que representam os principais grupos de risco da doença.
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Concepcion, O., O. de Melo, and A. Escobosa. "Substrate influence on Bi2Te3growth by MBE." In 2019 Latin American Electron Devices Conference (LAEDC). IEEE, 2019. http://dx.doi.org/10.1109/laed.2019.8714619.
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Potsch, Thomas, Safdar Nawaz Khan Khan Marwat, Yasir Zaki, and Carmelita Gorg. "Influence of future M2M communication on the LTE system." In 2013 6th Joint IFIP Wireless and Mobile Networking Conference (WMNC 2013). IEEE, 2013. http://dx.doi.org/10.1109/wmnc.2013.6549000.
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Ning, Chengda, Xianyong Jing, Yuanyuan Sun, and Zhihuan Lan. "The Influence of Multispectral Radiation Thermometry by Mie Scattering." In 2015 3rd International Conference on Mechanical Engineering and Intelligent Systems. Atlantis Press, 2015. http://dx.doi.org/10.2991/icmeis-15.2015.146.
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Wu, Chaoyan. "Influence of M2M Solution on Multimedia Communication Technology Development." In 2015 International Conference on Intelligent Systems Research and Mechatronics Engineering. Atlantis Press, 2015. http://dx.doi.org/10.2991/isrme-15.2015.41.
Full textReports on the topic "Influenza A M2e"
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Gentry, William. “It’s not about me. It’s me & you.” How being dumped can help first-time managers. Center for Creative Leadership, 2016. http://dx.doi.org/10.35613/ccl.2016.1071.
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This paper presents research from the Center for Creative Leadership that found (1) the type of motivation first-time managers have for learning and development; and (2) the skill gaps first-time managers have in four specific leadership competencies: communication, influence, leading team achievement, and coaching and developing others.
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Hoffman, Florian, and Philip Oreopoulos. A Professor Like Me: The Influence of Instructor Gender on College Achievement. National Bureau of Economic Research, 2007. http://dx.doi.org/10.3386/w13182.
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Tehrani, Fariborz M., Kenneth L. Fishman, and Farmehr M. Dehkordi. Extending the Service-Life of Bridges using Sustainable and Resilient Abutment Systems: An Experimental Approach to Electrochemical Characterization of Lightweight Mechanically Stabilized Earth. Mineta Transportation Institute, 2023. http://dx.doi.org/10.31979/mti.2023.2225.
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Bridges are critical components of transportation infrastructure. This research addresses the need to extend the service life of bridges by improving the safety and reliability of bridge abutments and reducing their life-cycle cost and footprints. Mechanically stabilized earth (MSE) is a known strategy to enhance the economy and performance of bridge abutments. In addition, the application of rotary-kiln-manufactured lightweight aggregate backfills improves the performance of MSE bridge abutments with a leaner structural system. Such improvements include a reduction of structural demands due to a lower density, free drainage of granular materials, a high internal friction angle, less settlement with no consolidation, and accelerated construction requiring less compaction effort. This project aims to assess the electrochemical properties of expanded shale, clay, and slate (ESCS) aggregates and their influence on the corrosion of embedded steel strips. The experimental methodology involves evaluating current testing methods to measure electrical resistivity, pH, sulfate, chloride, and corrosion considering various gradation, moisture, dilution, and curing conditions. Samples represent available sources of ESCS with one source of normal weight aggregates for comparison. Results indicate the appropriateness of ESCS for addressing corrosion in MSE backfills. Further, outcomes provide guidelines to categorically predict the corrosivity of steel reinforcement when ESCS is employed as fill within MSE systems. These guidelines can help optimize the design and reduce the need to maintain and rehabilitate bridges, abutments, and approach and departure slabs on roadways to keep transportation systems safe and cost-efficient for sustainable infrastructure.
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Baluga, Anthony, and Bruno Carrasco. The Role of Geography in Shaping Governance Performance. Asian Development Bank, 2020. http://dx.doi.org/10.22617/wps200378.
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This paper demonstrates that good governance in one country can influence governance improvements in neighboring countries and highlights that regional political and economic cooperation can benefit institutional development across borders. Governance has a spatial dimension due to spillovers and resource flows across juridical boundaries. This paper finds that governance in a given country—manifested most clearly through voice and accountability—exhibits a positive relationship with those in neighboring countries. Feedback mechanisms are traced in that any change in the income level of a country can affect its governance performance and also impact the governance scores of neighboring countries. This phenomenon is observed in the “Arab Spring,” “Me Too,” and “Black Lives Matter” cross-border movements
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Martinez, Hector, Kylie Rochford, and Diane Bergeron. Helping You, Helping Me? The Mediating Role of Organizational Citizenship Behavior in the Relationship Between Psychological Capital and Social Network Positions. Center for Creative Leadership, 2025. https://doi.org/10.35613/ccl.2025.2061.
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Over the past few decades, there has been an increasing shift from focusing on what is wrong with humans and organizations (e.g., problems, maladaptive behavior) to focusing on what is right (e.g., strengths, human and organizational flourishing). In this positive vein, we investigated the explanatory role of organizational citizenship behavior (e.g., helping others, volunteering for tasks that help the group or organization, organizing events, speaking up with ideas) in examining the relationship between psychological capital and social network positions. Psychological capital is an individual’s positive psychological state of development and is composed of four positive psychological resources: self-efficacy, optimism, hope, and resilience (Luthans & Youssef, 2004; Luthans & Youssef-Morgan, 2017). Employees with high levels of psychological capital (PsyCap) believe they have control over their own success (efficacy, hope), expect good things to happen (optimism), and rebound more easily following failure (resilience). In other words, PsyCap represents an individual’s positive evaluation of circumstances and likelihood for success based on their mindset, drive and persistence (Luthans, Avolio, Avey & Norman, 2007). Using social exchange theory, we hypothesized that higher PsyCap individuals, due to their greater citizenship behaviors (helping, speaking up), would be perceived as more attractive social exchange partners, thereby achieving greater social network centrality (i.e., having more relational connections in an organizational network). Network centrality is important because it is related to greater career success due to more access to the information, career sponsorship, and opportunities embedded within social networks. Our findings showed that those with higher PsyCap engaged in more workplace helping behaviors and more voice behaviors (i.e., speaking up, making suggestions). PsyCap was positively correlated with network centrality in the social support network (i.e., relationships based on camaraderie and affection), but not in the advice network (i.e., relationships based on information and assistance exchanges). Finally, helping (but not voice) behaviors mediated the relationship between PsyCap and network centrality across both types of social networks. See Figure 2 on page 4 for our supported empirical model. These insights suggest that fostering PsyCap can enhance an individual’s integration and influence within social support networks, with helping behavior playing a crucial explanatory role. Given the strong links between social network positions and important individual and organizational outcomes (e.g., greater access to the information, career sponsorship and opportunities embedded within social networks), understanding the factors that influence central network positions has implications for individual leaders and organizations. For leaders, higher PsyCap may result in greater network centrality because such individuals require fewer resources. For organizations, greater PsyCap may result in higher-performing teams and organizations – not only due to PsyCap but also to its positive relationship to citizenship behaviors (helping, voice), which research shows are related to greater organizational efficiency, profitability, productivity, and customer satisfaction. As such, leaders and organizations may want to invest in developing this malleable resource and assess the effectiveness of different PsyCap intervention strategies (see Table 4 for a summary). In sum, psychological capital is a source of competitive advantage – both for high PsyCap individuals as well as for the organizations employing them.
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Савосько, Василь Миколайович, Наталія Вікторівна Товстоляк, Юрій Васильович Лихолат, and Іван Панасович Григорюк. Structure and Diversity of Urban Park Stands at Kryvyi Rih Ore-Mining & Metallurgical District, Central Ukraine. Podgorica, 2020. http://dx.doi.org/10.31812/123456789/3946.
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The present study examines the relationships between structure (floristic composition, dendrometric parameters), diversity (diversity and evenness indexes) of urban forest park stands and the ecological (soil fertility, soil moisture), environmental factors (air pollution). The study is based on the forest park stands inventory data, performed from 2012 to 2017 in Kryvyi Rih City, Central Ukraine. The floristic compositions of the urban forest park stands are poor. There are only 23 species that belong to 14 families and 12 genera. More families were represented by at least more than 2% of taxon diversity. While Ulmaceae (2 genera, 4 species–17,39 %), Fabaceae (3 genera, 2 species–17,39 %), Aсеrасеае (1 genera, 4 species–17,39 %) were the most representative families. It was established that at forest park the values of stand density varied from 490 to 660 trees*ha-1, stem heights were from 26 to 31 m, stem diameters were from 13 to 17 cm, stand basal area were from 32 to 49 m2*ha-1, stand volume were from 200 to 415 m3*ha-1. the values of relative stem heights were from 0,63 to 0,82 m*year-1, relative stem diameters were from 0,31 to 0,43 cm*year-1, relative stand basal area were from 0,80 to 1,19 m2*ha-1*year-1, relative stand volume were from 5,45 to 10,28 m3*ha-1*year-1. The varied values of the forest park stands index (Shannon-Wiener diversity index from 0,75 to 1,61, Pielou‟s evenness index from 0,53 to 0,86, Simpson‟s diversity from 0,24 to 0,60, Margalef‟s diversity index from 0,87 to 6,97) indicate the ecological instability of these woody plant communities. Current state of the urban forest park stands determined by the combined influence of ecological (soil fertility, soil moisture) and environmental factors (air pollution).
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Wongkasemjit, Sujitra. Novel synthesis study of high surface area silica : final report. Chulalongkorn University, 2002. https://doi.org/10.58837/chula.res.2002.71.
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The sol-gel transition of tetra-coordinated spirosilicate via hydrolysis and condensation under acidic and basic conditions is examined to elucidate the effect of catalyst, reaction time and temperature on the properties of obtained gel. The main advantage of this process is the low temperature employed, producing a solid network with a high specific surface area. FTIR spectroscopy and TGA analysis were used to characterize the formation of siloxane bonds (Si-O-Si). It is found that spirosilicate can be hydrolyzed under both acid and base catalyzed conditions. The condensation rate to silicates is shown to be at a minimum in 1% of 1M HCl, which is the iso-electric point of silica. The prepared xerogel has a low-density and is an amorphous material with a specific surface area of 596 m2 /g. Besides the catalyst media, the type of precursor also has a strong influence on the gel formation. An aminospirosilicate, six-membered ring, containing methyl and amino groups as substituents, was chosen for this study. The resulting xerogel is determined by the fact that to obtain the Si-O-Si bonds, a higher concentration of solvent and higher temperature are more favorable, due to the stability of the ring and branching of alkyl portion.
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Peitz, David, and Tani Hubbard. Bird monitoring at Effigy Mounds National Monument, Iowa: Status report 2009?2022. National Park Service, 2024. http://dx.doi.org/10.36967/2303731.
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In 2009, the Heartland Inventory and Monitoring Network initiated bird surveys on Effigy Mounds National Monument to monitor changes in bird community composition and abundance and improve our understanding of relationships between breeding birds and their habitat and the effects of management actions on those relationships. This information helps park staff plan management objectives and assess the effectiveness of management alternatives. We evaluated park breeding bird trends in the context of trends observed within the North American Bird Conservation Initiative?s Prairie Hardwood Transition Bird Conservation Region where the park is located. This allows us to assess the influence of park habitat management on bird populations with an understanding of regional population trends that are outside the influence of natural resource management activities at the park. In 14 years (2009?2022) of monitoring, 111 bird species have been recorded on the park, 93 of which are considered breeding species (permanent or summer residents). Eight of these are species of concern for the Prairie Hardwood Transition Bird Conservation Region. Thirty-eight species were observed in sufficient numbers to calculate annual abundances and trends with some degree of statistical confidence. The American Redstart, American Robin, Baltimore Oriole, Eastern Wood-pewee, and Red-eyed Vireo were the most abundant and widespread species on the park. Regional trends (2009?2019; Sauer et al. 2020) were similar to those seen on the park with a few exceptions. American Robin, Brown-headed Cowbird, Common Grackle, and White-breasted Nuthatch were declining within the region but increasing within the park. Diversity, richness, and evenness in distribution of individuals across species in the breeding bird community on the park were unchanged over the 14 years. When sampled, habitats on the plots at Effigy Mounds National Monument consisted primarily of the woodland type, with lesser amounts of other types present. Canopy cover averaged 61 to 89% on plots with cover provided exclusively by hard?wood trees. Basal area of hardwood trees averaged between 12 and 22 m2/ha, and canopy height averaged between 20 and 23 m. Tree species from 14 different families contrib?uted to the canopy cover and basal area of plots. Plots were primarily unvegetated at ground level, with deciduous litter and woody debris common and bare soil exposed. Total foliar cover at ground level on plots consisted primarily of forbs.
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Peitz, David, and Tani Hubbard. Bird monitoring at Pipestone National Monument, Minnesota: Status report 2009?2022. National Park Service, 2024. http://dx.doi.org/10.36967/2303740.
Full textAbstract:
In 2009, the Heartland Inventory and Monitoring Network initiated bird surveys on Pipestone National Monument to monitor changes in bird community composition and abundance and improve our understanding of relationships between breeding birds and their habitat and the effects of management actions on those relationships. This information helps park staff plan management objectives and assess the effectiveness of management alternatives. We evaluated park breeding bird trends in the context of trends observed within the North American Bird Conservation Initiative?s Prairie Potholes Bird Conservation Region where the park is located. This allows us to assess the influence of park habitat management on bird populations with an understanding of regional population trends that are outside the influence of natural resource management activities at the park. In 14 years (2009?2022) of monitoring, 109 bird species were recorded on the park. Ninety-two of the species are considered breeding species (permanent or summer residents). Seven of these are species of concern for the Prairie Potholes Bird Conservation Region. Fifteen species were observed in sufficient numbers to calculate annual abundances and trends with some degree of statistical confidence. The Bobolink, American Robin, and Red-winged Blackbird were the most abundant and widespread species on the park. Comparisons of regional trends (2009?2019; Sauer et al. 2020) with park trends were inconclusive. Trends in 14 of the 15 abundant species on the park were uncertain. Common Yellowthroat was moderately increasing on the park. Regionally, American Robin, Dickcissel, and Yellow Warbler were increasing; the Bobolink, Clay-colored Sparrow, Eastern Kingbird, Grasshopper Sparrow, and Ring-necked Pheasant were declining; and the remaining seven species had uncertain population trends. Diversity, richness, and evenness in distribution of individuals across species in the breeding bird community on the park were unchanged over the 14 years. When sampled, habitats on the plots at Pipestone National Monument consisted primarily of the old field/prairie vegetation type, with lesser amounts of other types present. Canopy cover of hardwood trees averaged 5 to 7% on plots, basal area averaged 1 to 2 m2/ha, and canopy height averaged between 1 and 3 m. Tree species from 10 different families contrib?uted to the canopy cover and basal area of plots. Plots sampled were primarily unvegetated at ground level, with grass litter common, and rock and bare soil exposed. Total foliar cover at ground level on plots consisted primarily of cool season grasses and forbs.
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Peitz, David, and Tani Hubbard. Bird monitoring at Herbert Hoover National Historic Site, Iowa: Status report 2005?2022. National Park Service, 2024. http://dx.doi.org/10.36967/2303787.
Full textAbstract:
In 2005, the Heartland Inventory and Monitoring Network initiated bird surveys on Herbert Hoover National Historic Site to monitor changes in bird community composition and abundance and improve our understanding of relationships between breeding birds and their habitat and the effects of management actions on those relationships. This information helps park staff plan management objectives and assess the effectiveness of management alternatives. We evaluated park breeding bird trends in the context of trends observed within the North American Bird Conservation Initiative?s Eastern Tallgrass Prairie Bird Conservation Region where the park is located. This allows us to assess the influence of park habitat management on bird populations with an understanding of regional population trends that are outside the influence of natural resource management activities at the park. Seventy-four species of birds were recorded in 18 years (2005?2022). Seventy-one of the species are considered breeding species (permanent or summer residents). Seven of these are species of concern for the Eastern Tallgrass Prairie Bird Conservation Region. Nine species were observed in sufficient numbers to calculate annual abundances and trends with some degree of statistical confidence. The Red-winged Blackbird, American Robin and Dickcissel were the most abundant and widespread species on the park. Comparisons of regional trends (2005?2019; Sauer et al. 2020) with park population trends were inconclusive. Trends in the nine abundant species on the park were uncertain. Regionally, Dickcissel and Northern Cardinal were increasing. However, American Goldfinch, American Robin, Common Grackle, Common Yellowthroat, Eastern Meadowlark, Mourning Dove, and Red-winged Blackbird were declining regionally. Diversity, richness, and evenness in distribution of individuals across species in the park breeding bird community were unchanged over the 18 years. When sampled, habitats on the plots at Herbert Hoover National Historic Site consisted primarily of the old field/prairie type, with lesser amounts of other types present. Canopy cover averaged 2 to 13% on plots, with cover provided primarily by hard?wood trees. Basal area of hardwood trees averaged between 1 and 2 m2/ha, and canopy height averaged between 4 and 5 m. Tree species from 12 different families contrib?uted to the canopy cover and basal area of plots. Plots were primarily unvegetated at ground level, with grass litter common and bare soil exposed. Total foliar cover at ground level on consisted primarily of cool season grasses and forbs.