Substituent effects on the gas‐phase fragmentation reactions of protonated peptides containing benzylamine‐derivatized lysyl residues

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90273/1/rcm6141.pd

Modelling of single bubble-dynamics and thermal effects

This paper evaluates the solution effects of different Rayleigh-Plesset models (R-P) for simulating the growth/collapse dynamics and thermal behaviour of homogeneous gas bubbles. The flow inputs used for the discrete cavitation bubble calculations are obtained from Reynolds-averaged Navier-Stokes simulations (RANS), performed in high-pressure nozzle holes. Parametric 1-D results are presented for the classical thermal R-P equation [1] as well as for refined models which incorporated compressibility corrections and thermal effects [2, 3]. The thermal bubble model is coupled with the energy equation, which provides the temperature of the bubble as a function of conduction/convection and radiation heat-transfer mechanisms. For approximating gas pressure variations a high-order virial equation of state (EOS) was used, based on Helmholtz free energy principle [4]. The coded thermal R-P model was validated against experimental measurements [5] and model predictions [6] reported in single-bubble sonoluminescence (SBSL)

In ovo exposure to o,p -DDE affects sexual development but not sexual differentiation in Japanese medaka (Oryzias latipes).

Despite being banned in many countries, dichlorodiphenyltrichloroethane (DDT) and its metabolites dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) continue to be found in fish tissues at concentrations of concern. Like o,p -DDT, o,p -DDE is estrogenic and is believed to exert its effects through binding to the estrogen receptor. The limited toxicologic data for o,p -DDE suggest that it decreases fecundity and fertility of fishes. We conducted an egg injection study using the d-rR strain of medaka and environmentally relevant concentrations of o,p -DDE to examine its effects on sexual differentiation and development. The gonads of exposed fish showed no evidence of sex reversal or intersex. However, other gonad abnormalities occurred in exposed individuals. Females exhibited few vitellogenic oocytes and increased atresia. Male testes appeared morphologically normal but were very small. Gonadosomatic index values for both sexes were lower for exposed fish. Our observations of abnormal female and very small male gonads after in ovo o,p -DDE exposure may be indicative of effects on early endocrine processes important for normal ovarian and testicular development

Characterization of string cavitation in large-scale Diesel nozzles with tapered holes

The cavitation structures formed inside enlarged transparent replicas of tapered Diesel valve covered orifice nozzles have been characterized using high speed imaging visualization. Cavitation images obtained at fixed needle lift and flow rate conditions have revealed that although the conical shape of the converging tapered holes suppresses the formation of geometric cavitation, forming at the entry to the cylindrical injection hole, string cavitation has been found to prevail, particularly at low needle lifts. Computational fluid dynamics simulations have shown that cavitation strings appear in areas where large-scale vortices develop. The vortical structures are mainly formed upstream of the injection holes due to the nonuniform flow distribution and persist also inside them. Cavitation strings have been frequently observed to link adjacent holes while inspection of identical real-size injectors has revealed cavitation erosion sites in the area of string cavitation development. Image postprocessing has allowed estimation of their frequency of appearance, lifetime, and size along the injection hole length, as function of cavitation and Reynolds numbers and needle lif

First-principles study of As interstitials in GaAs: Convergence, relaxation, and formation energy

Convergence of density-functional supercell calculations for defect formation energies, charge transition levels, localized defect state properties, and defect atomic structure and relaxation is investigated using the arsenic split interstitial in GaAs as an example. Supercells containing up to 217 atoms and a variety of {\bf k}-space sampling schemes are considered. It is shown that a good description of the localized defect state dispersion and charge state transition levels requires at least a 217-atom supercell, although the defect structure and atomic relaxations can be well converged in a 65-atom cell. Formation energies are calculated for the As split interstitial, Ga vacancy, and As antisite defects in GaAs, taking into account the dependence upon chemical potential and Fermi energy. It is found that equilibrium concentrations of As interstitials will be much lower than equilibrium concentrations of As antisites in As-rich, $n$-type or semi-insulating GaAs.Comment: 10 pages, 5 figure

Coherent elastic neutrino-nucleus scattering: Terrestrial and astrophysical applications

Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) is a process in which neutrinos scatter on a nucleus which acts as a single particle. Though the total cross section is large by neutrino standards, CE$\nu$NS has long proven difficult to detect, since the deposited energy into the nucleus is $\sim$ keV. In 2017, the COHERENT collaboration announced the detection of CE$\nu$NS using a stopped-pion source with CsI detectors, followed up the detection of CE$\nu$NS using an Ar target. The detection of CE$\nu$NS has spawned a flurry of activities in high-energy physics, inspiring new constraints on beyond the Standard Model (BSM) physics, and new experimental methods. The CE$\nu$NS process has important implications for not only high-energy physics, but also astrophysics, nuclear physics, and beyond. This whitepaper discusses the scientific importance of CE$\nu$NS, highlighting how present experiments such as COHERENT are informing theory, and also how future experiments will provide a wealth of information across the aforementioned fields of physics