Differential Binding of Co(II) and Zn(II) to Metallo-β-Lactamase Bla2 from \u3cem\u3eBacillus anthracis\u3c/em\u3e

In an effort to probe the structure, mechanism, and biochemical properties of metallo-β-lactamase Bla2 from Bacillus anthracis, the enzyme was overexpressed, purified, and characterized. Metal analyses demonstrated that recombinant Bla2 tightly binds 1 equiv of Zn(II). Steady-state kinetic studies showed that mono-Zn(II) Bla2 (1Zn-Bla2) is active, while di-Zn(II) Bla2 (ZnZn-Bla2) was unstable. Catalytically, 1Zn-Bla2 behaves like the related enzymes CcrA and L1. In contrast, di-Co(II) Bla2 (CoCo-Bla2) is substantially more active than the mono-Co(II) analogue. Rapid kinetics and UV−vis, 1H NMR, EPR, and EXAFS spectroscopic studies show that Co(II) binding to Bla2 is distributed, while EXAFS shows that Zn(II) binding is sequential. To our knowledge, this is the first documented example of a Zn enzyme that binds Co(II) and Zn(II) via distinct mechanisms, underscoring the need to demonstrate transferability when extrapolating results on Co(II)-substituted proteins to the native Zn(II)-containing forms

Controllability and Design of Unmanned Multirotor Aircraft Robust to Rotor Failure

A new design method for multi-rotor aircraft with distributed electric propulsion is presented to ensure a property of robustness against rotor failure from the control perspective. Based on the concept of null controllability, a quality measure is derived to evaluate and quantify the performance of a given design with the consideration of rotor failure. An optimization problem whose cost function is based on the quality measure is formulated and its optimal solution identifies a set of optimal design parameters that maximizes an aircraft’s ability to control its attitude and hence its position. The effectiveness of the proposed design procedure is validated through the results of experimentation with the Autonomous Flying Ambulance model being developed at Caltech’s Center for Autonomous Systems and Technologies

Neonate Atlantic Sharpnose Shark (Rhizoprionodon terraenovae) Relative Abundance and Body Condition in Two South Carolina Estuaries Varying in Urbanization

Urbanization near estuaries has been shown to affect the growth and survival of juvenile sharks using the system as a nursery. North Inlet and Murrells Inlet, South Carolina, are similarly-sized, tidally-dominated, bar-built estuaries with extensive Sporobolus-lined tidal creeks but differ in degree of human impact. Previously, Murrells Inlet was shown to have a lower abundance and diversity of large sharks than North Inlet and Atlantic Sharpnose Sharks (Rhizoprionodon terraenovae) were shown to use North Inlet as a primary nursery. To examine potential differences in neonate shark abundance and growth between a developed estuary, Murrells Inlet, and a protected estuary, North Inlet, fifty-two neonate R. terraenovae were captured on hook-and-line gear from May to September 2022. Sharks were measured for length and girth, weighed, sexed, and released. Noise pollution between the two estuaries was investigated using hydrophone recordings. Relative abundance of neonate R. terraenovae was much greater for North Inlet (n = 45) than for Murrells Inlet (n = 7). However, body condition, weight-length relationships, girth-length relationships, and growth rates of the neonate sharks did not differ between the estuaries. Elasmobranch diversity was greater for Murrells Inlet than North Inlet, though bony fish diversity was equal between estuaries. Analysis of sound found no difference in the total loudness of the recordings between estuaries or the sound power of the recordings for shark hearing frequency ranges (p = 0.57, p = 0.45, respectively). Sampling sites were deeper for North Inlet and there was more boat traffic at Murrells Inlet, however, there was no correlation between the sound recordings and depth or boat traffic for either estuary. Although the difference in urbanization between estuaries did not affect the growth and body condition of R. terraenovae, the drivers behind the difference in abundance of neonates are still unclear

A versatile gene trap to visualize and interrogate the function of the vertebrate proteome

We report a multifunctional gene-trapping approach, which generates full-length Citrine fusions with endogenous proteins and conditional mutants from a single integration event of the FlipTrap vector. We identified 170 FlipTrap zebrafish lines with diverse tissue-specific expression patterns and distinct subcellular localizations of fusion proteins generated by the integration of an internal citrine exon. Cre-mediated conditional mutagenesis is enabled by heterotypic lox sites that delete Citrine and “flip” in its place mCherry with a polyadenylation signal, resulting in a truncated fusion protein. Inducing recombination with Cerulean-Cre results in fusion proteins that often mislocalize, exhibit mutant phenotypes, and dramatically knock down wild-type transcript levels. FRT sites in the vector enable targeted genetic manipulation of the trapped loci in the presence of Flp recombinase. Thus, the FlipTrap captures the functional proteome, enabling the visualization of full-length fluorescent fusion proteins and interrogation of function by conditional mutagenesis and targeted genetic manipulation

Traveling the Boundaries of Statelessness: Global Passports and Citizenship

An independent global citizenship without a local component and in the absence of the much-feared global government creates two concerns. One, an individual may imperil the rights of others, without a structure that can impose sanctions for the heinous conduct. Two, an individual\u27s rights may be imperiled, and there may be no entity to provide protection. This essay proposes a model of a formal global citizenship that will alleviate these concerns and prove both practically and theoretically feasible. The model flows from the concept of dual or multiple nationality and offers global citizenship only as an elective nationality. Such citizenship would co-exist with the nationality acquired by birth or naturalization, thereby guaranteeing that at least one nation-state always has the ultimate responsibility for the individual. At the same time, by providing for careful considerations on who may acquire global citizenship, the value and meaning inherent in citizenship can be preserved and enhanced. Indeed, the idea of a global citizenship that is a formalized development emerging from the human rights tradition can be a foundation for the attainment of full personhood by those marginalized or disempowered within their own or foreign national borders -- the poor, racial and ethnic minorities, indigenous populations, and women who at present lack equal status in any local or global community

Inclusive jet cross section in pˉp{\bar p p} collisions at s=1.8\sqrt{s}=1.8 TeV

The inclusive jet differential cross section has been measured for jet transverse energies, $E_T$, from 15 to 440 GeV, in the pseudorapidity region 0.1$\leq | \eta| \leq$0.7. The results are based on 19.5 pb$^{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron collider. The data are compared with QCD predictions for various sets of parton distribution functions. The cross section for jets with $E_T>200$ GeV is significantly higher than current predictions based on O($\alpha_s^3$) perturbative QCD calculations. Various possible explanations for the high-$E_T$ excess are discussed.Comment: 8 pages with 2 eps uu-encoded figures Submitted to Physical Review Letter

Critical Frequencies in the Stagnation Region of a Shock Layer

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77543/1/AIAA-9199-138.pd