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Background: Pharmacist-led medication reviews (MR) are one of the key methods to support medication safety in polypharmacy patients. The aims of this study were to pilot MRs in Eastern European community pharmacies, describe medication use in polypharmacy patients, and evaluate the usability of medication safety assessment tools. Methods: The MR pilot was undertaken in Estonia, Latvia, Poland, Hungary, Romania, and Bulgaria. Patients who used at least five medicines were directed to the service by their GPs. Data on drug-related problems (DRPs) and adherence were collected by pharmacists through structured patient interviews. Databases for identification of potential drug-drug interactions (pDDIs) and adverse drug reactions (ADRs) named Inxbase/Riskbase, as well as an integrated tool comprising potentially inappropriate medicines (PIMs) lists EU(7)-PIM and EURO-FORTA, were applied retroactively to the MR pilot data to investigate possibilities for their use and to describe medication use and potential risks in the study population. Results: A total of 318 patients were included in the study, 250 of them elderly (≥65 years). One hundred and eighty (56.6%) participants had a total of 504 pDDIs based on Inxbase analysis. On average, there were 1.6 pDDIs per participant. Twenty-five (5.0%) of the 504 pDDIs were in a high-risk category. A total of 279 (87.7%) participants had a potential ADR in at least one of 10 Riskbase categories. One hundred and fifty-four (20.8%) of the potential ADRs were in a high-risk category. Twenty-seven pDDIs and 68 ADRs documented as DRPs during the service were not included in the databases. Using the integrated EU(7)-PIM/EURO-FORTA PIM list, a total of 816 PIMs were found in 240 (96%) of the 250 elderly participants (on average 3.4 PIMs per elderly participant). Seventy-one (29.6%) of the participants were using high-risk PIMs. Twenty-one percent of high-risk PIMs and 13.8% of medium-risk PIMs were documented as DRPs by the pharmacists during the pilot. Conclusion: Medication safety assessment tools can be useful in guiding decision-making during MRs; however, these tools cannot replace patient interviews and monitoring. Tools that include a thorough explanation of the potential risks and are easy to use are more beneficial for MRs.
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OBJECTIVES: To assess the antiviral effect, clinical outcomes, and safety of the respiratory syncytial virus (RSV) fusion inhibitor rilematovir in non-hospitalized RSV-infected adults. METHODS: This phase 2a, double-blind, multicentre study randomly assigned RSV-positive adult outpatients ≤5 days from symptom onset 1:1:1 to receive rilematovir 500 mg, 80 mg, or placebo once-daily for 7 days. Antiviral effect was assessed by RSV RNA viral load (VL), measured by quantitative RT-PCR, and Kaplan-Meier (KM) estimates of time to undetectable VL. Clinical course was assessed by KM estimates of median time to resolution of key RSV symptoms assessed through patient-reported outcomes. RESULTS: RSV-positive patients (n = 72) were randomly assigned; 66 had confirmed RSV infection and received rilematovir 500 mg (n = 23), 80 mg (n = 21) or placebo (n = 22). Differences versus placebo in mean RSV RNA VL area under the curve (90% CI) through days 3, 5 and 8, respectively, were 0.09 (-0.837; 1.011), -0.10 (-2.171; 1.963), and -1.03 (-4.746; 2.682) log10 copies.day/mL for rilematovir 500 mg, and 1.25 (0.291; 2.204), 2.53 (0.430; 4.634), and 3.85 (0.097; 7.599) log10 copies.day/mL for rilematovir 80 mg. KM estimates of median (90% CI) time-to-first confirmed undetectable VL were 5.9 (3.85; 6.90), 8.0 (6.86; 12.80) and 7.0 (6.62; 10.88) days and 5.7 (2.93; 7.01), 8.1 (6.74; 12.80) and 7.9 (6.62; 11.74) days in patients with symptom onset ≤3 days, for rilematovir 500 mg, 80 mg, and placebo, respectively. KM estimates of median (90% CI) time to resolution of key RSV symptoms were 7.1 (5.03; 11.43), 7.6 (5.93; 8.32), and 9.6 (5.95; 14.00) days for rilematovir 500 mg, 80 mg, and placebo, respectively; and in patients with symptom onset ≤3 days, median 8.0, 7.6, and 11.8 days, respectively. DISCUSSION: Rilematovir use, initiated early, suggests a potential clinical benefit in RSV-infected adults, with data supporting development of RSV therapeutic options. TRIAL REGISTRATION: This study is registered with clinicaltrials.gov (NCT03379675).
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Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Adulto , Humanos , Antivirais/efeitos adversos , Método Duplo-Cego , Infecções por Vírus Respiratório Sincicial/tratamento farmacológico , RNARESUMO
The immunologic significance of cross-reactivity of TCR recognition of peptide:MHC complexes is still poorly understood. We have described TCR cross-reactivity in a system involving polyclonal CD8 T cell recognition of the well characterized influenza viral M158-66 epitope. While M158-66 is generally conserved between influenza A isolates, error-prone transcription generates stable variant RNA during infection which could act as novel epitopes. If packaged and viable, variant genomic RNA generates an influenza quasispecies. The stable RNA variants would generate a new transmissible epitope that can select a specific repertoire, which itself should have cross-reactive properties. We tested two candidate peptides in which Thr65 is changed to Ala (A65) or Ser (S65) using recall responses to identify responding T cell clonotypes. Both peptides generated large polyclonal T cell repertoires of their own with repertoire characteristics and cross-reactivity patterns like that observed for the M158-66 repertoire. Both substitutions could be present in viral genomes or mRNA at sufficient frequency during an infection to drive immunity. Peptides from the resulting protein would be a target for CD8 cells irrespective of virus viability or transmissibility. These data support the hypothesis that cross-reactivity is important for immunity against RNA virus infections.
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Vírus da Influenza A , Influenza Humana , Epitopos de Linfócito T , Humanos , Peptídeos , RNA , RNA Mensageiro , Receptores de Antígenos de Linfócitos T/genéticaRESUMO
Type 1 diabetes (T1D) is an autoimmune disorder defined by CD8 T cell-mediated destruction of pancreatic ß cells. We have previously shown that diabetogenic CD8 T cells in the islets of non-obese diabetic mice are phenotypically heterogeneous, but clonal heterogeneity remains relatively unexplored. Here, we use paired single-cell RNA and T-cell receptor sequencing (scRNA-seq and scTCR-seq) to characterize autoreactive CD8 T cells from the islets and spleens of non-obese diabetic mice. scTCR-seq demonstrates that CD8 T cells targeting the immunodominant ß-cell epitope IGRP206-214 exhibit restricted TCR gene usage. scRNA-seq identifies six clusters of autoreactive CD8 T cells in the islets and six in the spleen, including memory and exhausted cells. Clonal overlap between IGRP206-214-reactive CD8 T cells in the islets and spleen suggests these cells may circulate between the islets and periphery. Finally, we identify correlations between TCR genes and T-cell clonal expansion and effector fate. Collectively, our work demonstrates that IGRP206-214-specific CD8 T cells are phenotypically heterogeneous but clonally restricted, raising the possibility of selectively targeting these TCR structures for therapeutic benefit.
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Diabetes Mellitus Experimental , Animais , Linfócitos T CD8-Positivos , Diabetes Mellitus Experimental/genética , Genes Codificadores dos Receptores de Linfócitos T , Camundongos , Camundongos Endogâmicos NOD , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T/genéticaRESUMO
In type 1 diabetes (T1D) autoreactive CD8 T cells infiltrate pancreatic islets and destroy insulin-producing ß cells. Progression to T1D onset is a chronic process, which suggests that the effector activity of ß-cell autoreactive CD8 T cells needs to be maintained throughout the course of disease development. The mechanism that sustains diabetogenic CD8 T cell effectors during the course of T1D progression has not been completely defined. Here we used single-cell RNA sequencing to gain further insight into the phenotypic complexity of islet-infiltrating CD8 T cells in NOD mice. We identified two functionally distinct subsets of activated CD8 T cells, CD44highTCF1+CXCR6- and CD44highTCF1-CXCR6+, in islets of prediabetic NOD mice. Compared with CD44highTCF1+CXCR6- CD8 T cells, the CD44highTCF1-CXCR6+ subset expressed higher levels of inhibitory and cytotoxic molecules and was more prone to apoptosis. Adoptive cell transfer experiments revealed that CD44highTCF1+CXCR6- CD8 T cells, through continuous generation of the CD44highTCF1-CXCR6+ subset, were more capable than the latter population to promote insulitis and the development of T1D. We further showed that direct IL-27 signaling in CD8 T cells promoted the generation of terminal effectors from the CD44highTCF1+CXCR6- population. These results indicate that islet CD44highTCF1+CXCR6- CD8 T cells are a progenitor-like subset with self-renewing capacity, and, under an IL-27-controlled mechanism, they differentiate into the CD44highTCF1-CXCR6+ terminal effector population. Our study provides new insight into the sustainability of the CD8 T cell response in the pathogenesis of T1D.
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Linfócitos T CD8-Positivos/imunologia , Diabetes Mellitus Tipo 1/imunologia , Interleucina-27/metabolismo , Linfócitos T Citotóxicos/imunologia , Animais , Diferenciação Celular , Autorrenovação Celular , Células Cultivadas , Modelos Animais de Doenças , Progressão da Doença , Fator 1-alfa Nuclear de Hepatócito/metabolismo , Humanos , Células Secretoras de Insulina/imunologia , Camundongos , Camundongos Endogâmicos NODRESUMO
In the course of a total synthesis effort directed toward the natural product curcusone C, the Stoltz group discovered an unexpected thermal rearrangement of a divinylcyclopropane to the product of a formal Cope/1,3-sigmatropic shift sequence. Since the involvement of a thermally forbidden 1,3-shift seemed unlikely, theoretical studies involving two approaches, the "trial-and-error" testing of various conceivable mechanisms (Houk group) and an "automatic" approach using the Maeda-Morokuma AFIR method (Morokuma group) were applied to explore the mechanism. Eventually, both approaches converged on a cascade mechanism shown to have some partial literature precedent: Cope rearrangement/1,5-sigmatropic silyl shift/Claisen rearrangement/retro-Claisen rearrangement/1,5-sigmatropic silyl shift, comprising a quintet of five sequential thermally allowed pericyclic rearrangements.
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Diterpenos/síntese química , Modelos Químicos , Algoritmos , Teoria da Densidade Funcional , IsomerismoRESUMO
This paper reports a quantum chemical study of all stages of a one-pot synthesis of pyrrolidinedione derivatives from nitromethane and coumarin, which includes Michael addition, migration of an oxygen atom (Nef-type rearrangement), and cyclization to a pyrrolidine ring. The energy barrier of deprotonated nitromethane addition to coumarin is 21.7 kJ mol-1, while the barrier of proton transfer from the methylene to the nitro group in the nitromethyl group is notably higher, 197.8 kJ mol-1. The second stage of the reaction, migration of an oxygen atom within the nitromethyl group, occurs with lowest energy barrier, 142.4 kJ mol-1, when it is assisted by an additional water molecule. The last stage - cyclization, passes with a very low energy barrier of 11.9 kJ mol-1 but the tautomerization of the nitrosohydroxymethyl group to the hydroxy-N-hydroxyiminomethyl, necessary for the process, has an energy barrier of 178.4 kJ mol-1. Analogous calculations for the same process with the ethyl ester of 3-coumarin-carboxylic acid as substrate show that the relative energies of the intermediates and transition states are by at most 10-16 kJ mol-1 more stable than the corresponding structures with coumarin.
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The present study assessed the importance of immunity in angiotensin (ANG) II (5 ng·kg-1·min-1 iv)-mediated hypertension in Dahl salt-sensitive (SS) rats and SS rats deficient in T and B lymphocytes (SSRag1-/-) fed a 0.4% NaCl diet. Baseline mean arterial blood pressure (MAP) was not different between groups. ANG II infusion significantly increased MAP in both groups, although MAP increased more rapidly in SS rats, and the maximal MAP achieved was significantly greater in SS than SSRag1-/- rats (190 ± 3 vs. 177 ± 3 mmHg) after 12 days. Renal damage, as assessed by albumin excretion rate, was significantly increased after 12 days of ANG lI infusion in SS (from 32 ± 4 to 81 ± 9 mg/day) and SSRag1-/- (from 12 ± 2 to 51 ± 8 mg/day) rats; albumin excretion rate was significantly different between SS and SSRag1-/- rats at all points measured. After 9 days of recovery from ANG II, MAP was decreased to a greater extent in SSRag1-/- than SS rats (143 ± 5 vs. 157 ± 8 mmHg) compared with the peak MAP during ANG II infusion. At this same time point, albumin excretion rate was significantly lower in SSRag1-/- than SS rats (42 ± 8 vs. 66 ± 7 mg/day). Further studies demonstrated an increase in CD45+ total leukocytes, CD11b/c+ macrophages/monocytes, and CD3+ T cells in kidneys of ANG II- compared with vehicle-treated SS rats. The present data suggest that infiltrating T cells in the kidney exacerbate renal damage in ANG II-induced hypertension in SS rats maintained on a 0.4% NaCl diet, similar to results observed with a salt stimulus in SS rats.
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Angiotensina II , Hipertensão/imunologia , Nefropatias/imunologia , Rim/imunologia , Linfócitos T/imunologia , Albuminúria/induzido quimicamente , Albuminúria/imunologia , Albuminúria/metabolismo , Albuminúria/fisiopatologia , Animais , Pressão Arterial , Linfócitos B/imunologia , Linfócitos B/metabolismo , Quimiotaxia de Leucócito , Citocinas/imunologia , Citocinas/metabolismo , Modelos Animais de Doenças , Genes RAG-1 , Hipertensão/induzido quimicamente , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Rim/metabolismo , Rim/patologia , Rim/fisiopatologia , Nefropatias/induzido quimicamente , Nefropatias/metabolismo , Nefropatias/fisiopatologia , Masculino , Fenótipo , Ratos Endogâmicos Dahl , Ratos Sprague-Dawley , Ratos Transgênicos , Cloreto de Sódio na Dieta , Linfócitos T/metabolismoRESUMO
The synthesis method including wave-optics and ray-tracing for the acceleration of the simulation of micro-optical systems has been developed. The effects of the spatial coherence and randomization of microlens array (MLA) parameters have been considered. The method based on coherent states representation for the calculation of the optical efficiency of microlens arrays taking into account the light source polarization has been developed. Numerical simulations of the intensity distributions and spreading angle of a diffracted beam have been carried out.
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Renal T-cell infiltration is a key component of salt-sensitive hypertension in Dahl salt-sensitive (SS) rats. Here, we use an electronic servo-control technique to determine the contribution of renal perfusion pressure to T-cell infiltration in the SS rat kidney. An aortic balloon occluder placed around the aorta between the renal arteries was used to maintain perfusion pressure to the left kidney at control levels, ≈128 mm Hg, during 7 days of salt-induced hypertension, whereas the right kidney was exposed to increased renal perfusion pressure that averaged 157±4 mm Hg by day 7 of high-salt diet. The number of infiltrating T cells was compared between the 2 kidneys. Renal T-cell infiltration was significantly blunted in the left servo-controlled kidney compared with the right uncontrolled kidney. The number of CD3+, CD3+CD4+, and CD3+CD8+ T cells were all significantly lower in the left servo-controlled kidney. This effect was not specific to T cells because CD45R+ (B cells) and CD11b/c+ (monocytes and macrophages) cell infiltrations were all exacerbated in the hypertensive kidneys. Increased renal perfusion pressure was also associated with augmented renal injury, with increased protein casts and glomerular damage in the hypertensive kidney. Levels of norepinephrine were comparable between the 2 kidneys, suggestive of equivalent sympathetic innervation. Renal infiltration of T cells was not reversed by the return of renal perfusion pressure to control levels after 7 days of salt-sensitive hypertension. We conclude that increased pressure contributes to the initiation of renal T-cell infiltration during the progression of salt-sensitive hypertension in SS rats.
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Movimento Celular/imunologia , Hipertensão , Rim , Linfócitos T , Animais , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Modelos Animais de Doenças , Hipertensão/etiologia , Hipertensão/patologia , Hipertensão/fisiopatologia , Rim/irrigação sanguínea , Rim/imunologia , Rim/patologia , Ratos , Ratos Endogâmicos Dahl , Artéria Renal/fisiopatologia , Cloreto de Sódio/farmacologia , Linfócitos T/patologia , Linfócitos T/fisiologiaRESUMO
A series of novel cluster compounds comprising molybdenum in a low valence state was synthesized by means of a disproportionation of the dimeric compound [Mo+42Cl4(OCH3)4(CH3OH)2] (1). The reaction of 1 with CH3OH leads to the disproportionation of Mo+4 yielding an unusual mixed-valence cluster [Mo+3.54Cl4O2(OCH3)6(CH3OH)4] (2). By exploring this synthetic approach further, tri-{[Mo3Cl3(OCH3)7(CH3OH)3] (3)}, tetra-{[Mo4Cl4(OCH3)10(CH3OH)2] (4), [Mo4Cl3O(OCH3)9(CH3OH)3] (5), [Mo4Cl2(OCH3)12(CH3OH)2] (6)}, and hexanuclear {[Mo6Cl4O6(OCH3)10(CH3OH)2] (7)} molybdenum alkoxides were synthesized by the reaction of 1 with methanol and stoichiometric amounts of magnesium methoxide, thus providing a general facile access to the polynuclear methoxide complexes of a low-valence molybdenum. Due to the feasibility to adopt multiple oxidation states in a reversible manner and the documented competence of molybdenum alkoxide compounds to catalyze the reduction of inert molecules, including N2, the synthesized compounds were expected to function as catalysts of small molecule substrates reduction/hydrogenation. Accordingly, the reduction of acetylene (C2H2) to an ethylene (C2H4) and ethane (C2H6) mixture, in methanol (with water additives) serving as a reaction medium and a proton donor, and using sodium or europium amalgams as reducing agents, was performed in the presence of 2. Preliminary kinetic studies evidently point to a catalytic function of molybdenum species derived from 2, thus establishing the observed reactivity as a rare example of non-precious metal-catalyzed acetylene hydrogenation, providing, in addition, a convenient model for further mechanistic studies.
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The origin of higher reactivity in water-accelerated asymmetric aldol reactions with our designed primary amine organocatalyst was elucidated by both computational and experimental methods. As suggested by the calculated transition-state structures for water-promoted imine-enamine isomerization, anti-selective aldol reaction and hemiaminal formation, the rate of this aldol reaction was found experimentally to be even more accelerated by the addition of cis-2-butene-1,4-diol as additive.
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Intrinsic fluorescence quenching of bovine serum albumin (BSA) and europium(III) luminescence in BSA complexes were investigated. The number of BSA binding sites (n) and equilibrium constant (Keq) values were determined from both measurements provided qualitatively different results. While the modified Stern-Volmer relation for BSA fluorescence quenching gave n = 1 at pH 4.5 and pH 6, two sets of binding sites were determined from Eu(3+) luminescence with n1 = 2, n2 = 4 at pH 6 and n1 = 1, n2 = 2 at pH 4.5. The model explaining the discrepancy between the results obtained by these fluorescent approaches was suggested, and the limitations in application of the "log-log" Stern-Volmer plots in analysis of binding processes were discussed.
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Európio/química , Soroalbumina Bovina/química , Animais , Sítios de Ligação , Bovinos , Európio/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Ligação Proteica , Soroalbumina Bovina/metabolismo , Espectrometria de FluorescênciaRESUMO
A thorough theoretical study of phase-transfer quaternary ammonium catalysts designed by the Maruoka group has been performed in an attempt to gain better understanding of the properties and catalytic behavior of the homo- and heterochiral forms of these systems. The conformationally flexible analogue is found to easily undergo interconversion from the homo- to the heterochiral form driven by the higher thermodynamic stability of the heterochiral isomer and resulting in alternation in catalytic behavior. Theoretical calculations of (1)H NMR spectra of the two isomers for different model systems are in good agreement with the experimental data, allowing us to conclude that the upfield shift of signals for the benzylic protons in the heterochiral form could be explained by an increase in the shielding effect of the aromatic parts of the system around these protons due to the conformational changes. By applying the automated transition state (TS) search procedure for the alkylation of glycine derivatives catalyzed by the homo-/heterochiral form of a conformationally rigid analogue, we were able to locate more than 40 configurations of the TS structures. In brief, the homochiral form was theoretically confirmed to catalyze the formation of the predominant R-product, while for the heterochiral form the catalytic activity is found to depend on two factors: (i) formation of a tight ion pair between the catalyst and the glycine derivative, which results in a decrease in the reaction rate, in agreement with the experimental data, and formation of only the R-product, and (ii) the possibility that the reaction occurs without the initial formation of the ion pair or after its dissociation, in which case the formation of an S-product is predominant. The combined effects of both factors would explain the lower reaction rate and the poor enantioselectivity observed experimentally for the heterochiral form.
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T-cell receptors recognize peptides presented by the major histocompatibility complex (MHC) on the surface of antigen-presenting cells (APC). The ability of the T-cell receptor (TCR) to recognize more than one peptide-MHC structure defines cross-reactivity. Cross-reactivity is a documented phenomenon of the immune system whose importance is still under investigation. There are a number of rational arguments for cross-reactivity. These include the discrepancy between the theoretical high number of pathogen-derived peptides and the lower diversity of the T-cell repertoire, the need for recognition of escape variants, and the intrinsic low affinity of this receptor-ligand pair. However, quantifying the phenomenon has been difficult, and its immunological importance remains unknown. In this review, we examined the cases for and against an important role for cross reactivity. We argue that it may be an essential feature of the immune system from the point of view of biological robustness.
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Sistema Imunitário/imunologia , Linfócitos T/imunologia , Animais , Humanos , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T/metabolismoRESUMO
Memory T-cell repertoires are populated by clonotypes selected by an individual's history of antigen exposures. Our previous analysis of middle-age CD8(+) T-cell memory repertoires to the influenza-derived epitope M1(58-66) , described a network of highly cross-reactive BV19 clonotypes responding to M1(58-66) and at least one peptide with a conservative amino acid substitution at either of two TCR contact positions. Here, we report that some substitutions abrogate BV19 responses and favor responses with different BV. Cross-reactive T cells using seven other BV families responded to 12 of 13 peptides tested. BV12 clonotypes define the most extensive cross-reactive network that encompasses seven peptides. We generated 3D networks based on the peptides recognized and BV family used and observed a cluster of five peptides that includes M1(58-66) and another cluster of five peptides that does not include M1(58-66) . The first cluster represents peptides structurally similar to M1(58-66) , and the second represents peptides with more considerable changes in epitope recognition surface. We hypothesize that the second cluster represents the cross-reactive network around another unknown epitope or epitopes. This data supports a model of stable CD8(+) T-cell memory networks that include a substantial contribution from cross-reactive T cells.
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Linfócitos T CD8-Positivos/imunologia , Memória Imunológica/imunologia , Vírus da Influenza A/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Proteínas da Matriz Viral/imunologia , Adulto , Linfócitos T CD8-Positivos/virologia , Clonagem Molecular , Reações Cruzadas/imunologia , Epitopos/imunologia , Humanos , Leucócitos Mononucleares/imunologia , Pessoa de Meia-Idade , RNA/química , RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Proteínas da Matriz Viral/genéticaRESUMO
"Reverse" spillover of hydrogen from hydroxyl groups of the support onto supported transition metal clusters, forming multiply hydrogenated metal species, is an essential aspect of various catalytic systems which comprise small, highly active transition metal particles on a support with a high surface area. We review and analyze the results of our computational model studies related to reverse hydrogen spillover, interpreting available structural and spectral data for the supported species and examining the relationship between metal-support and metal-hydrogen interactions. On the examples of small clusters of late transition metals, adsorbed in zeolite cavities, we showed with computational model studies that reverse spillover of hydrogen is energetically favorable for late transition metals, except for Au. This preference is crucial for the chemical reactivity of such bifunctional catalytic systems because both functions, of metal species and of acidic sites, are strongly modified, in some cases even suppressed - due to partial oxidation of the metal cluster and the conversion of protons from acidic hydroxyl groups to hydride ligands of the metal moiety. Modeling multiple hydrogen adsorption on metal clusters allowed us to quantify how (i) the support affects the adsorption capacity of the clusters and (ii) structure and oxidation state of the metal moiety changes upon adsorption. In all models of neutral systems we found that the metal atoms are partially positively charged, compensated by a negative charge of the adsorbed hydrogen ligands and of the support. In a case study we demonstrated with calculated thermodynamic parameters how to predict the average hydrogen coverage of the transition metal cluster at a given temperature and hydrogen pressure.
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The study reports a computational analysis of the influence of proton donor group adjacent to the reaction center during ester ammonolysis of an acylated diol as a model reaction for peptide bond formation. This analysis was performed using catalytic maps constructed after a detailed scanning of the available space around the reaction centers in different transition states, a water molecule acting as a typical proton donor. The calculations suggest that an adjacent proton donor center can reduce the activation barrier of the rate determining transition states by up to 7.2 kcal/mol, while no inhibition of the reaction can be achieved by such a group.