Search Results (40)

Background: Modern viral vector production needs to consider process intensification for higher yields from smaller production volumes. However, innate antiviral immunity triggered in the producer cell may limit virus replication. While commonly used cell lines (e.g., Vero or E1A-immortalised cells) are already compromised in antiviral pathways, the redundancy of innate signaling complicates host cell optimization by genetic engineering. Small molecules that are hypothesized to target antiviral pathways (Viral Sensitizers, VSEs) added to the culture media offer a versatile alternative to genetic modifications to increase permissiveness and, thus, viral yields across multiple cell lines. Methods: To explore how the yield for a chimeric Zika vaccine candidate (YF-ZIK) could be further be increased in an intensified bioprocess, we used spin tubes or an Ambr15 high-throughput microbioreactor system as scale-down models to optimize the dosing for eight VSEs in three host cell lines (AGE1.CR.pIX, BHK-21, and HEK293-F) based on their tolerability. Results: Addition of VSEs to an already optimized infection process significantly increased infectious titers by up to sevenfold for all three cell lines tested. The development of multi-component VSE formulations using a design of experiments approach allowed further synergistic titer increases in AGE1.CR.pIX cells. Scale-up to 1 L stirred-tank bioreactors and 3D-printed mimics of 200 or 2000 L reactors resulted in up to threefold and eightfold increases, respectively. Conclusions: Addition of single VSEs or combinations thereof allowed a further increase in YF-ZIK titers beyond the yield of an already optimized, highly intensified process. The described approach validates the use of VSEs and can be instructive for optimizing other virus production processes. Full article

The emergence of SARS-CoV-2 variants escaping immunity challenges the efficacy of current vaccines. Here, we investigated humoral recall responses and vaccine-mediated protection in Syrian hamsters immunized with the third-generation Comirnaty^® Omicron XBB.1.5-adapted COVID-19 mRNA vaccine, followed by infection with either antigenically closely (EG.5.1) or distantly related (JN.1) Omicron subvariants. Vaccination with the YF17D vector encoding a modified Gamma spike (YF-S0*) served as a control for SARS-CoV-2 immunity restricted to pre-Omicron variants. Our results show that both Comirnaty^® XBB.1.5 and YF-S0* induce robust, however, poorly cross-reactive, neutralizing antibody (nAb) responses. In either case, total antibody and nAb levels increased following infection. Intriguingly, the specificity of these boosted nAbs did not match the respective challenge virus, but was skewed towards the primary antigen used for immunization, suggesting a marked impact of antigenic imprinting, confirmed by antigenic cartography. Furthermore, limited cross-reactivity and rapid decline in nAbs induced by Comirnaty^® XBB.1.5 with EG.5.1 and, more concerning, JN.1, raises doubts about sustained vaccine efficacy against recent circulating Omicron subvariants. In conclusion, we demonstrate that antigenic imprinting plays a dominant role in shaping humoral immunity against emerging SARS-CoV-2 variants. Future vaccine design may have to address two major issues: (i) overcoming original antigenic sin that limits the breadth of a protective response towards emerging variants, and (ii) achieving sustained immunity that lasts for at least one season. Full article

Background/Objectives: Yellow fever virus (YFV) (Flaviviridae, Orthoflavivirus) is the etiologic agent of yellow fever (YF), a vector-borne disease with significant morbidity and mortality across the tropics and neotropics, despite having a highly efficacious and safe vaccine (17D). Vaccination provides lifelong protection from YF disease mediated by humoral immunity. There are several versions of the original 17D vaccine: 17D-204 (marketed in the USA as YF-VAX, in France as Stamaril, and in China as Tiantan-V), 17D-213 (Russian Federation), and 17DD (by FIOCRUZ in Brazil). Vaccines produced in the US, France, Senegal, China, and Russia represent 17D-204-derived strains, whereas the Brazilian 17DD has a unique passage/attenuation history from 17D-204-derived strains. Their functional differences in the neutralization profiles are not known. Methods: The Plaque Reduction Neutralization Test (PRNT) was used to determine the neutralization profiles of sera from 209 patients that were previously vaccinated with the 17DD strain against both 17D-204 and 17DD. Results: Sera exhibited significantly more efficient neutralization of 17DD (mean reciprocal PRNT₅₀ 183, PRNT₈₀ 86, median reciprocal PRNT₅₀ 80, and PRNT₈₀ 40) compared to 17D-204 (mean reciprocal PRNT₅₀ 91, PRNT₈₀ 33, median reciprocal PRNT₅₀ 40, and PRNT₈₀ 10). Conclusions: Our data indicate antigenic differences between 17D and 17DD vaccines. Full article

Abutment scour is a major cause of bridge failures worldwide, leading to disruptions, economic losses, and loss of life. The present experimental study examines countermeasures against abutment scour using hooked-collar protections on vertical-wall and wing-wall abutments (at 45° and 60°) under different flow conditions. All 60 experiments were performed under sub-critical flow conditions by investigating scour around an abutment 20 cm long, 20 cm wide, and 25 cm tall. Two distinct values of the Froude number, 0.154 and 0.179, and a sediment particle diameter (d₅₀) of 0.88 mm were used throughout the experimental phase. The resulting equilibrium scour around the abutments was compared to those with collar and hooked-collar protections. It was determined that the maximum abutment scour depth reduction was 83.89% when hooked collars were placed on vertical wall abutments beneath the bed surface level, and for wing-wall abutments at 45° and 60°, it was 74.2% and 73.5%, respectively, at the bed surface level. Regression analysis was conducted to assess the non-dimensional scour depth (D_s/Y_f) and scour reduction (R_Ds/Y_f), with a high enough coefficient of determination (R² values of 0.96 and 0.93, respectively), indicating high confidence in the analysis. The sensitivity analysis findings demonstrate that the width of the collar (W_c) and L_a are the most influencing factors affecting D_s/Y_f and RD_s/Y_f. Full article

Yellow fever (YF), caused by the yellow fever virus (YFV), continually spreads and causes epidemics worldwide, posing a great threat to human health. The live-attenuated YF 17D vaccine (YF-17D) has been licensed for preventing YFV infection and administrated via the intramuscular (i.m.) route. In this study, we sought to determine the immunogenicity and protective efficacy of aerosolized YF-17D via the intratracheal (i.t.) route in mice. YF-17D stocks in liquids were successfully aerosolized into particles of 6 μm. Further in vitro phenotype results showed the aerosolization process did not abolish the infectivity of YF-17D. Meanwhile, a single i.t. immunization with aerosolized YF-17D induced robust humoral and cellular immune responses in A129 mice, which is comparable to that received i.p. immunization. Notably, the aerosolized YF-17D also triggered specific secretory IgA (SIgA) production in bronchoalveolar lavage. Additionally, all immunized animals survived a lethal dose of YFV challenge in mice. In conclusion, our results support further development of aerosolized YF-17D in the future. Full article

The live-attenuated yellow fever 17D strain is a potent vaccine and viral vector. Its manufacture is based on embryonated chicken eggs or adherent Vero cells. Both processes are unsuitable for rapid and scalable supply. Here, we introduce a high-throughput workflow to identify suspension cells that are fit for the high-yield production of live YF17D-based vaccines in an intensified upstream process. The use of an automated parallel ambr15 microbioreactor system for screening and process optimization has led to the identification of two promising cell lines (AGE1.CR.pIX and HEK_Dyn) and the establishment of optimized production conditions, which have resulted in a >100-fold increase in virus titers compared to the current state of the art using adherent Vero cells. The process can readily be scaled up from the microbioreactor scale (15 mL) to 1 L stirred tank bioreactors. The viruses produced are genetically stable and maintain their favorable safety and immunogenicity profile, as demonstrated by the absence of neurovirulence in suckling BALB/c mice and consistent seroprotection in AG129 mice. In conclusion, the presented workflow allows for the rapid establishment of a robust, scalable, and high-yield process for the production of live-attenuated orthoflavivirus vaccines, which outperforms current standards. The approach described here can serve as a model for the development of scalable processes and the optimization of yields for other virus-based vaccines that face challenges in meeting growing demands. Full article

YF₃: (Eu³⁺, Nd³⁺) nanoparticles (orthorhombic phase, D~130 nm) were synthesized via the co-precipitation method, with subsequent hydrothermal treatment and annealing. The Eu³⁺ τ_decay linearly descends with the increase of temperature in the 80–320 K range. The τ_decay (T) slope values of the annealed YF₃: Eu³⁺ (2.5 and 5.0 mol.%) nanoparticles were the highest (110·10⁻⁴ and 67·10⁻⁴, μs/K) in the whole 80–320 K range, respectively. Thus, these samples were chosen for further doping with Nd³⁺. The maximum S_a and S_r values based on the LIR (I_Eu/I_Nd) function were 0.067 K⁻¹ (at 80 K) and 0.86%·K⁻¹ (at 154 K), respectively. As mentioned above, the single-doped YF₃: Eu³⁺ (2.5%) nanoparticles showed the linearly decreasing τ_decay (T) function (⁵D₀–⁷F₁ emission). The main idea of Nd³⁺ co-doping was to increase this slope value (as well as the sensitivity) by increasing the rate of τ_decay (T) descent via the addition of one more temperature-dependent channel of ⁵D₀ excited state depopulation. Indeed, we managed to increase the slope (S_a) to 180·10⁻⁴ K⁻¹ at 80 K. This result is one of the highest compared to the world analogs. Full article

Centrifugal compressors are commonly used in heating, ventilation, and air conditioning (HVAC) systems. The current generation of refrigerants in HVAC systems have very low ozone depletion potential, but most of them are still considered as containing high global warming potential (GWP) chemicals. Facing the regulatory pressure to eliminate the high-level GWP refrigerants, some of the existing HVAC systems will need to switch to low-GWP refrigerants. In this paper, we studied the performance changes in a refrigerant centrifugal compressor when switching from R134a to R1234ze(E) and R1234yf through a method that combined numerical simulation and an 1D meanline code. By combining these two methods, a reliable compressor performance change prediction was generated using limited results from the computational fluid dynamics (CFD) simulations. The results show that the property differences in the working fluid can significantly change the refrigerant compressor performance, including the compressor efficiency, pressure ratio, power consumption, working range and cooling capacity. Full article

The yellow fever (YF) vaccine is one of the safest and most effective vaccines currently available. Still, its administration in people living with HIV (PLWH) is limited due to safety concerns and a lack of consensus regarding decreased immunogenicity and long-lasting protection for this population. The mechanisms associated with impaired YF vaccine immunogenicity in PLWH are not fully understood, but the general immune deregulation during HIV infection may play an important role. To assess if HIV infection impacts YF vaccine immunogenicity and if markers of immune deregulation could predict lower immunogenicity, we evaluated the association of YF neutralization antibody (NAb) titers with the pre-vaccination frequency of activated and exhausted T cells, levels of pro-inflammatory cytokines, and frequency of T cells, B cells, and monocyte subsets in PLWH and HIV-negative controls. We observed impaired YF vaccine immunogenicity in PLWH with lower titers of YF-NAbs 30 days after vaccination, mainly in individuals with CD4 count <350 cells/mm³. At the baseline, those individuals were characterized by having a higher frequency of activated and exhausted T cells and tissue-like memory B cells. Elevated levels of those markers were also observed in individuals with CD4 count between 500 and 350 cells/mm³. We observed a negative correlation between the pre-vaccination level of CD8⁺ T cell exhaustion and CD4⁺ T cell activation with YF-NAb titers at D365 and the pre-vaccination level of IP-10 with YF-NAb titers at D30 and D365. Our results emphasize the impact of immune activation, exhaustion, and inflammation in YF vaccine immunogenicity in PLWH. Full article

The COVID-19 pandemic has made assessing vaccine efficacy more challenging. Besides neutralizing antibody assays, systems vaccinology studies use omics technology to reveal immune response mechanisms and identify gene signatures in human peripheral blood mononuclear cells (PBMCs). However, due to their low proportion in PBMCs, profiling the immune response signatures of dendritic cells (DCs) is difficult. Here, we develop a predictive model for evaluating early immune responses in dendritic cells. We establish a THP-1-derived dendritic cell (TDDC) model and stimulate their maturation in vitro with an optimal dose of attenuated yellow fever 17D (YF-17D). Transcriptomic analysis reveals that type I interferon (IFN-I)-induced immunity plays a key role in dendritic cells. IFN-I regulatory biomarkers (IRF7, SIGLEC1) and IFN-I-inducible biomarkers (IFI27, IFI44, IFIT1, IFIT3, ISG15, MX1, OAS2, OAS3) are identified and validated in vitro and in vivo. Furthermore, we apply this TDDC approach to various types of vaccines, providing novel insights into their early immune response signatures and their heterogeneity in vaccine recipients. Our findings suggest that a standardizable TDDC model is a promising predictive approach to assessing early immunity in DCs. Further research into vaccine efficacy assessment approaches on various types of immune cells could lead to a systemic regimen for vaccine development in the future. Full article

With the development of sustainable agriculture, the application of organic fertilizers to crops instead of chemical fertilizers has become an inevitable trend. However, little is known about the proportion of organic fertilizers replacing chemical fertilizers and how it affects the underlying microbial mechanisms of continuous pineapple soil. In this study, we used the Illumina Miseq high-throughput sequencing platform to study the rhizosphere soil of continuously cropped pineapples to study the diversity and community structure of pineapple rhizosphere microorganisms. The results showed that, with 97% similarity, the number of OTUs of all samples obtained using hierarchical clustering analysis is 3645. Both conventional fertilization (CF) and optimal fertilization (YF) increased the relative abundance of Proteobacteria, Actinomycetes, and Sclericutes, and decreased the relative abundance of Acidobacteria, Bacteroidetes, Blastomonas, and Verrucobacteria. The replacement of organic fertilizers increased the relative abundance of Bacteroidetes, among which the relative abundance of chlorocurvus treated with the replacement of organic fertilizers of 80% was the highest. Different fertilization methods also changed the diversity and abundance of bacteria in the soil of the pineapple rhizosphere; the diversity of the species was E > D > C > CK > B > YF > CF. Based on the analysis of the PCoA and NMDS of soil bacterial communities, treatment E was similar to treatment D, treatment CK was similar to treatment YF, and treatment C and treatment D had little structural difference. On the basis of an analysis of the composition and function of the flora, it can be found that different fertilization methods have significant differences in the bacterial groups of the rhizosphere bacterial community of pineapple soil. The relative abundance of beneficial bacteria was increased. When organic fertilizer replaces chemical fertilizer, it promotes the role of bacteria related to the carbon cycle in the rhizosphere. Full article

A lanthanide contraction(LC) of 14 lanthanides (Ln) from ₅₈Ce to ₇₁Lu consists of the interaction of Ln nucleus with 4f-electrons. Rare earth elements (REEs—R) include Sc, Y, La, and 14 Ln. They are located in 4–6th periods of the subgroup of group III. The electronic structure divides R into short (d- Sc, Y, La) and long (14 f-elements Ce-Lu) homologous series. The most important chemical consequence of LC is the creation of a new conglomerate of 16 RF₃ by mixing fluorides of d- (Y, La) and f-elements. This determines the location of YF₃ among LnF₃. The location of YF₃ depends on the structural (formula volumes—V_form) and thermochemical (temperatures and heats of phase transformations, phase diagrams) properties. The location of YF₃ between HoF₃ and ErF₃ was determined by V_form at a standard pressure (P_st) and temperature (T_st). The location of YF₃ according to heats of phase transformations ΔH_fus and ΔH_trans is in a dimorphic structural subgroup (SSGr) D (Ln = Er-Lu), but without the exact “pseudo Z_Y”. According to the temperatures of phase transformations (T_trans) in LnF₃ (Ln = Dy-Lu), YF₃ is located in the SSGr D between ErF₃ and TmF₃. The ErF₃-YF₃ and YF₃-TmF₃ phase diagrams show it to be between ErF₃ and TmF₃. The crystals of five β-LnF₃ (Ln = Ho-Lu) and β-YF₃ were obtained in identical conditions and their crystal structures were studied. V_form (at P_st and T_st) with “pseudo” atomic number Z_Y = 67.42 was calculated from the unit cell parameters, which were defined with ±5 × 10⁻⁴ Å accuracy. It determines the location of YF₃ between HoF₃ and ErF₃. Full article

We present a combination of light-sheet excitation and two-dimensional fluorescence intensity ratio (FIR) measurements as a simple and promising technique for three-dimensional temperature mapping. The feasibility of this approach is demonstrated with samples fabricated with sodium yttrium fluoride nanoparticles co-doped with rare-earth ytterbium and erbium ions (NaYF₄:Yb³⁺/Er³⁺) incorporated into polydimethylsiloxane (PDMS) as a host material. In addition, we also evaluate the technique using lipid-coated NaYF₄:Yb³⁺/Er³⁺ nanoparticles immersed in agar. The composite materials show upconverted (UC) fluorescence bands when excited by a 980 nm near-infrared laser light-sheet. Using a single CMOS camera and a pair of interferometric optical filters to specifically image the two thermally-coupled bands (at 525 and 550 nm), the two-dimensional FIR and, hence, the temperature map can be readily obtained. The proposed method can take optically sectioned (confocal-like) images with good optical resolution over relatively large samples (up to the millimetric scale) for further 3D temperature reconstruction. Full article

The present study is aimed at unveiling the luminescence potential of Ba_4−xSr_3+x(BO₃)_4−yF_2+3y (BSBF) crystals doped with Eu³⁺, Tb³⁺, and Ce³⁺. Owing to the incongruent melting character of the phase, the NaF compound was used as a solvent for BSBF crystal growth. The structure of BSBF: Eu³⁺ with Eu₂O₃ concentration of about 0.7(3) wt% was solved in the non-centrosymmetric point group P6₃mc. The presence of Eu₂O₃ in BSBF: Eu³⁺ leads to a shift of the absorption edge from 225 nm to 320 nm. The photoluminescence properties of the BSBF: Ce³⁺, BSBF: Tb³⁺, BSBF: Eu³⁺, and BSBF: Eu³⁺, Tb³⁺, Ce³⁺ crystals have been studied. The unusual feature of europium emission in BSBF is the intensively manifested ⁵D₀→⁷F₀ transition at about 574 nm, which is the strongest for BSBF: Eu³⁺ at 370 nm excitation and for BSBF: Eu³⁺, Tb³⁺, Ce³⁺ at 300 nm and 370 nm excitations. No evidence of Tb³⁺→Eu³⁺ energy transfer was found for BSBF: Eu³⁺, Tb³⁺, Ce³⁺. The PL spectra of BSBF: Eu³⁺ at 77 and 300 K are similar with CIE chromaticity coordinates of (0.617; 0.378) at 300 nm excitation and (0.634; 0.359) at 395 nm excitation and low correlated color temperature which implies application prospects in the field of lightning. Due to the high intensity of ⁵D₀→⁷F₀ Eu³⁺ transition at 370 nm excitation, the BSBF: Eu³⁺ emission is yellow-shifted. Full article

Modern biocompatible materials of both natural and synthetic origin, in combination with advanced techniques for their processing and functionalization, provide the basis for tissue engineering constructs (TECs) for the effective replacement of specific body defects and guided tissue regeneration. Here we describe TECs fabricated using electrospinning and 3D printing techniques on a base of synthetic (polylactic-co-glycolic acids, PLGA) and natural (collagen, COL, and hyaluronic acid, HA) polymers impregnated with core/shell β-NaYF₄:Yb³⁺,Er³⁺/NaYF₄ upconversion nanoparticles (UCNPs) for in vitro control of the tissue/scaffold interaction. Polymeric structures impregnated with core/shell β-NaYF₄:Yb³⁺,Er³⁺/NaYF₄ nanoparticles were visualized with high optical contrast using laser irradiation at 976 nm. We found that the photoluminescence spectra of impregnated scaffolds differ from the spectrum of free UCNPs that could be used to control the scaffold microenvironment, polymer biodegradation, and cargo release. We proved the absence of UCNP-impregnated scaffold cytotoxicity and demonstrated their high efficiency for cell attachment, proliferation, and colonization. We also modified the COL-based scaffold fabrication technology to increase their tensile strength and structural stability within the living body. The proposed approach is a technological platform for “smart scaffold” development and fabrication based on bioresorbable polymer structures impregnated with UCNPs, providing the desired photoluminescent, biochemical, and mechanical properties for intravital visualization and monitoring of their behavior and tissue/scaffold interaction in real time. Full article