Generation of Nanomaterials by Reactive Laser Synthesis in Liquid

Nanomaterials with tailored structures and surface chemistry are in high demand, as these materials play increasingly important roles in biology, catalysis, energy storage, and manu- facturing. Their heightened demand has attracted attention towards the development of syn- thesis routes, particularly, laser-synthesis techniques. These efforts drove the refinement of laser ablation in liquid (LAL) and related methods over the past two decades, and have led to the emergence of reactive laser-synthesis techniques that exploit these methods’ character- istic, non-equilibrium conditions. Reactive laser-synthesis approaches foster unique chemical reactions that enable the formation of composite products like multimetallic nanoparticles, supported nanostructures, and complex minerals. This review will examine emerging reac- tive laser-synthesis methods in the context of established methods like LAL. The focus will be on the chemical reactions initiated within the laser plasma, with the goal of understanding how these reactions lead to the formation of unique nanomaterials. We will provide the first systematic review of laser reaction in liquid (LRL) in the literature, and bring a focus to the chemical reaction mechanisms in LAL and reactive-LAL techniques that have not yet been em- phasized in reviews. Discussion of the current challenges and future investigative opportunities into reactive laser-synthesis will impart guidance for researchers interested in designing reactive laser-synthesis approaches to novel nanomaterial production

On the Dynamical Ferromagnetic, Quantum Hall, and Relativistic Effects on the Carbon Nanotubes Nucleation and Growth Mechanism

The mechanism of carbon nanotube (CNT) nucleation and growth has been a mystery for over 15 years. Prior models have attempted the extension of older classical transport mechanisms. In July 2000, a more detailed and accurate nonclassical, relativistic mechanism was formulated considering the detailed dynamics of the electronics of spin and orbital rehybridization between the carbon and catalyst via novel mesoscopic phenomena and quantum dynamics. Ferromagnetic carbon was demonstrated. Here, quantum (Hall) effects and relativistic effects of intense many body spin-orbital interactions for novel orbital rehybridization dynamics (Little Effect) are proposed in this new dynamical magnetic mechanism. This dynamic ferromagnetic mechanism is proven by imposing dynamic and static magnetic fields during CNT syntheses and observing the different influence of these external magnetic environments on the catalyzing spin currents and spin waves and the resulting CNT formation

Theoretical and Experimental Considerations for Neutrinoless Double Beta Decay

In the rst part of this work we show some theoretical aspects of the generation of the neutrino mass by means of a direct extension of the Standard Model of particles, which include the presence of heavy right-handed neutrinos and large Majorana mass terms. From these two new ingredients, it is possible to nd a mass for the light neutrinos which is naturally of the order of 1 eV or less. The idea is to put these theoretical aspects in the context of the search for neutrino mass values by the study of the signal from the Neutrinoless Double Beta Decay Process (0 ). In the second part, a brief summary is given of the experimental considerations required for the measurement of effective Majorana neutrino mass using (0 ). Measurement strategies and background considerations are introduced and an outline of both active and passive methods is given. Finally, current results are discussed with particular emphasis on the HeidelbergMoscow experiment. This note is based on the presentation given at the CERNCLAF 4th Latin American School on High-Energy Physics

Effective Control of Chronic γ-Herpesvirus Infection by Unconventional MHC Class Ia–Independent CD8 T Cells

Control of virus infection is mediated in part by major histocompatibility complex (MHC) Class Ia presentation of viral peptides to conventional CD8 T cells. Although important, the absolute requirement for MHC Class Ia–dependent CD8 T cells for control of chronic virus infection has not been formally demonstrated. We show here that mice lacking MHC Class Ia molecules (K(b−/−)xD(b−/−) mice) effectively control chronic γ-herpesvirus 68 (γHV68) infection via a robust expansion of β(2)-microglobulin (β(2)-m)-dependent, but CD1d-independent, unconventional CD8 T cells. These unconventional CD8 T cells expressed: (1) CD8αβ and CD3, (2) cell surface molecules associated with conventional effector/memory CD8 T cells, (3) TCRαβ with a significant Vβ4, Vβ3, and Vβ10 bias, and (4) the key effector cytokine interferon-γ (IFNγ). Unconventional CD8 T cells utilized a diverse TCR repertoire, and CDR3 analysis suggests that some of that repertoire may be utilized even in the presence of conventional CD8 T cells. This is the first demonstration to our knowledge that β(2)-m–dependent, but Class Ia–independent, unconventional CD8 T cells can efficiently control chronic virus infection, implicating a role for β(2)-n–dependent non-classical MHC molecules in control of chronic viral infection. We speculate that similar unconventional CD8 T cells may be able to control of other chronic viral infections, especially when viruses evade immunity by inhibiting generation of Class Ia–restricted T cells

From Neutral Aniline to Aniline Trication: A Computational and Experimental Study

We report density functional theory computations and photoionization mass spectrometry measurements of aniline and its positively charged ions. The geometrical structures and properties of the neutral, singly, doubly, and triply positively charged aniline are computed using density functional theory with the generalized gradient approximation. At each charge, there are multiple isomers closely spaced in total energy. Whereas the lowest energy states of both neutral and cation have the same topology C6H5–NH2, the dication and trication have the C5NH5–CH2 topology with the nitrogen atom in the meta and para positions, respectively. We compute the dissociation pathways of all four charge states to NH or NH+ and NH2 or NH2+, depending on the initial charge of the aniline precursor. Dissociation leading to the formation of NH (from the neutral and cation) and NH+ (from the dication and trication) proceeds through multiple transition states. On the contrary, the dissociation of NH2 (from the neutral, cation) and NH2+ (from the dication and trication) is found to proceed without an activation energy barrier. The trication was found to be stable toward abstraction on NH+ and NH2+by 0.96 eV and 0.18 eV, respectively, whereas the proton affinity of the trication is substantially higher, 1.98 eV. The mass spectra of aniline were recorded with 1300 nm, 20 fs pulses over the peak intensity range of 1 x 1013 W cm-2 to 3 x 1014W cm-2. The analysis of the mass spectra suggests high stability of both dication and trication to fragmentation. The formation of the fragment NH+ and NH2+ ions is found to proceed via Coulomb explosion

Dissociation of Singly and Multiply Charged Nitromethane Cations: Femtosecond Laser Mass Spectrometry and Theoretical Modeling

Dissociation pathways of singly- and multiply charged gas-phase nitromethane cations were investigated with strong-field laser photoionization mass spectrometry and density functional theory computations. There are multiple isomers of the singly charged nitromethane radical cation, several of which can be accessed by rearrangement of the parent CH3–NO2 structure with low energy barriers. While direct cleavage of the C–N bond from the parent nitromethane cation produces NO2+ and CH3+, rearrangement prior to dissociation accounts for fragmentation products including NO+, CH2OH+, and CH2NO+. Extensive Coulomb explosion in fragment ions observed at high laser intensity indicates that rapid dissociation of multiply charged nitromethane cations produces additional species such as CH2+, H+, and NO22+.  On the basis of analysis of Coulomb explosion in the mass spectral signals and pathway calculations, sufficiently intense laser fields can remove four or more electrons from nitromethane

Risk Factors Associated With Hospitalization and Death in COVID-19 Breakthrough Infections

BACKGROUND: Characterizations of coronavirus disease 2019 (COVID-19) vaccine breakthrough infections are limited. We aim to characterize breakthrough infections and identify risk factors associated with outcomes. METHODS: This was a retrospective case series of consecutive fully vaccinated patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a multicenter academic center in Southeast Michigan, between December 30, 2020, and September 15, 2021. RESULTS: A total of 982 patients were identified; the mean age was 57.9 years, 565 (59%) were female, 774 (79%) were White, and 255 (26%) were health care workers (HCWs). The median number of comorbidities was 2; 225 (23%) were immunocompromised. BNT162b2 was administered to 737 (75%) individuals. The mean time to SARS-CoV-2 detection was 135 days. The majority were asymptomatic or exhibited mild to moderate disease, 154 (16%) required hospitalization, 127 (13%) had severe-critical illness, and 19 (2%) died. Age (odds ratio [OR], 1.14; 95% CI, 1.04-1.07; P \u3c .001), cardiovascular disease (OR, 3.02; 95% CI, 1.55-5.89; P = .001), and immunocompromised status (OR, 2.57; 95% CI, 1.70-3.90; P \u3c .001) were independent risk factors for hospitalization. Additionally, age (OR, 1.06; 95% CI, 1.02-1.11; P = .006) was significantly associated with mortality. HCWs (OR, 0.15; 95% CI, 0.05-0.50; P = .002) were less likely to be hospitalized, and prior receipt of BNT162b2 was associated with lower odds of hospitalization (OR, 0.436; 95% CI, 0.303-0.626; P \u3c .001) and/or death (OR, 0.360; 95% CI, 0.145-0.898; P = .029). CONCLUSIONS: COVID-19 vaccines remain effective at attenuating disease severity. However, patients with breakthrough infections necessitating hospitalization may benefit from early treatment modalities and COVID-19-mitigating strategies, especially in areas with substantial or high transmission rates