Quantum Dot-Organic Molecule Conjugates as Hosts for Photogenerated Spin Qubit Pairs.

The inherent spin polarization present in photogenerated spin-correlated radical pairs makes them promising candidates for quantum computing and quantum sensing applications. The spin states of these systems can be probed and manipulated with microwave pulses using electron paramagnetic resonance spectrometers. However, to date, there are no reports on magnetic resonance-based spin measurements of photogenerated spin-correlated radical pairs hosted on quantum dots. In the current work, we prepare dye molecule-inorganic quantum dot conjugates and show that they can produce photogenerated spin-polarized states. The dye molecule, D131, is chosen for its ability to undergo efficient charge separation, and the nanoparticle materials, ZnO quantum dots, are chosen for their promising spin properties. Transient and steady state optical spectroscopy performed on ZnO quantum dot-D131 conjugates shows that reversible photogenerated charge separation is occurring. Transient and pulsed electron paramagnetic resonance experiments are then performed on the photogenerated radical pair, which demonstrate that (1) the radical pair is polarized at moderate temperatures and well modeled by existing theories and (2) the spin states can be accessed and manipulated with microwave pulses. This work opens the door to a new class of promising qubit materials that can be photogenerated in polarized states and hosted by highly tailorable inorganic nanoparticles.

Quantification of mast cells in nonreactive and reactive lesions of gingiva: A comparative study using toluidine blue and immunohistochemical marker mast cell tryptase.

Background: Mast cells (MCs) are immune cells derived from a multipotent CD34 precursor. The most significant identifying feature of MCs is the presence of metachromatic granules. MCs are increased in oral reactive lesions and are possibly involved in pathogenesis of these lesions. Objectives: 1. To compare the number of MCs between reactive and nonreactive lesions of gingiva using toluidine blue (TB) and mast cell tryptase (MCT) as a specific marker for MCs 2. To compare the staining specificity/efficacy of TB and MCT. Methodology: The study sample comprised 90 tissues which were divided into three groups: Group A comprised 30 cases of pyogenic granuloma (PG), Group B consisted of 30 cases of gingival hyperplasia (GH) and Group C comprised 30 cases of pericoronitis. Staining was done between 1% TB and immunohistochemistry (IHC) marker MCT. Results: A significant increase in number of MCs was observed in PG as compared to GH and pericoronitis. IHC marker MCT proved to be a more specific marker for MCs compared to TB. Conclusion: IHC marker MCT is a specific marker compared to TB. The position of MCs changed from juxtaepithelial in GH to deeper connective tissue in PG which was in correlation with the proliferating tissue that is epithelium in GH and blood vessel in PG.

Age-Related Effect of Viral-Induced Wheezing in Severe Prematurity.

Premature children are prone to severe viral respiratory infections in early life, but the age at which susceptibility peaks and disappears for each pathogen is unclear. Methods: A retrospective analysis was performed of the age distribution and clinical features of acute viral respiratory infections in full-term and premature children, aged zero to seven years. Results: The study comprised of a total of 630 hospitalizations (n = 580 children). Sixty-seven percent of these hospitalizations occurred in children born full-term (>37 weeks), 12% in preterm (32-37 weeks) and 21% in severely premature children (<32 weeks). The most common viruses identified were rhinovirus (RV; 60%) and respiratory syncytial virus (RSV; 17%). Age-distribution analysis of each virus identified that severely premature children had a higher relative frequency of RV and RSV in their first three years, relative to preterm or full-term children. Additionally, the probability of RV- or RSV-induced wheezing was higher overall in severely premature children less than three years old. Conclusions: Our results indicate that the vulnerability to viral infections in children born severely premature is more specific for RV and RSV and persists during the first three years of age. Further studies are needed to elucidate the age-dependent molecular mechanisms that underlie why premature infants develop RV- and RSV-induced wheezing in early life.

Premature infants have impaired airway antiviral IFNγ responses to human metapneumovirus compared to respiratory syncytial virus.

BACKGROUND: It is unknown why human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) cause severe respiratory infection in children, particularly in premature infants. Our aim was to investigate if there are defective airway antiviral responses to these viruses in young children with history of prematurity. METHODS: Nasal airway secretions were collected from 140 children ≤ 3 y old without detectable virus (n = 80) or with PCR-confirmed HMPV or RSV infection (n = 60). Nasal protein levels of IFNγ, CCL5/RANTES, IL-10, IL-4, and IL-17 were determined using a multiplex magnetic bead immunoassay. RESULTS: Full-term children with HMPV and RSV infection had increased levels of nasal airway IFNγ, CCL5, and IL-10 along with an elevation in Th1 (IFNγ)/Th2 (IL-4) ratios, which is expected during antiviral responses. In contrast, HMPV-infected premature children (< 32 wk gestation) did not exhibit increased Th1/Th2 ratios or elevated nasal airway secretion of IFNγ, CCL5, and IL-10 relative to uninfected controls. CONCLUSION: Our study is the first to demonstrate that premature infants have defective IFNγ, CCL5/RANTES, and IL-10 airway responses during HMPV infection and provides novel insights about the potential reason why HMPV causes severe respiratory disease in children with history of prematurity.

Rhinovirus-induced airway cytokines and respiratory morbidity in severely premature children.

BACKGROUND: Rhinovirus (RV) has been linked to the pathogenesis of asthma. Prematurity is a risk factor for severe RV infection in early life, but is unknown if RV elicits enhanced pro-asthmatic airway cytokine responses in premature infants. This study investigated whether young children born severely premature (<32 wks gestation) exhibit airway secretion of Th2 and Th17 cytokines during natural RV infections and whether RV-induced Th2-Th17 responses are linked to more respiratory morbidity in premature children during the first 2 yrs of life. METHODS: We measured Th2 and Th17 nasal airway cytokines in a retrospective cohort of young children aged 0-2 yrs with PCR-confirmed RV infection or non-detectable virus. Protein levels of IL-4, IL-13, TSLP, and IL-17 were determined with multiplex immunoassays. Demographic and clinical variables were obtained by electronic medical record (EMR) review. RESULTS: The study comprised 214 children born full term (n = 108), preterm (n = 44) or severely premature (n = 62). Natural RV infection in severely premature children was associated with elevated airway secretion of Th2 (IL-4 and IL-13) and Th17 (IL-17) cytokines, particularly in subjects with history of bronchopulmonary dysplasia. Severely premature children with high RV-induced airway IL-4 had recurrent respiratory hospitalizations (median 3.65 hosp/yr; IQR 2.8-4.8) and were more likely to have at least one pediatric intensive care unit admission during the first 2 yrs of life (OR 8.72; 95% CI 1.3-58.7; p = 0.02). CONCLUSIONS: Severely premature children have increased airway secretion of Th2 and Th17 cytokines during RV infections, which is associated with more respiratory morbidity in the first 2 yrs of life.

In silico analysis and modeling of putative T cell epitopes for vaccine design of Toscana virus.

The sandfly fever Toscana virus is an important etiological agent known to cause human neurological infections in endemic Mediterranean countries during summer season. In the present study, prediction and modeling of T cell epitopes of Toscana virus (TOSV) antigenic proteins followed by the binding simulation studies of predicted highest binding scorers with their corresponding MHC class II alleles were done. Immunoinformatics was applied in computational vaccinology to analyze the viral proteins which generate possible outcomes to elicit vaccine for TOSV. Here, immunoinformatic tool ProPred was used to predict the promiscuous MHC class II epitopes of viral antigenic proteins. The molecular modeling of the selected epitopes as well as MHC alleles was done at CPH model 3.2 server. Molecular dynamics (MD) simulation studies were performed through the NAMD graphical user interface embedded in visual molecular dynamics. The epitope/peptide VKMMIVLNL of viral nucleoprotein as well as VMILGLLSS of viral glycoprotein has shown the highest binding score with the same DRB1*1104 MHC II allele. These two predicted peptides are highly potential to induce T cell-mediated immune response and are expected to be useful in designing epitope-based vaccines after further testing. The results signify that the nucleoprotein, glycoprotein or the combination of both could be useful for future development of a vaccine controlling the spread of this emerging virus that could pose a new threat for humans.