Jun Lu

Bio: Jun Lu is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Medicine & Materials science. The author has an hindex of 135, co-authored 1526 publications receiving 99767 citations. Previous affiliations of Jun Lu include Drexel University & Argonne National Laboratory.

Limits on quark-lepton compositeness scales from dileptons produced in 1.8 TeV pp-collisions

Abstract: The dilepton mass spectrum in p{bar p}{r_arrow}l{sup +}l{sup {minus}}+X interactions is studied using dielectrons ({ital ee}) and dimuons ({mu}{mu}) in 110 pb{sup {minus}1} of data collected with the Collider Detector at Fermilab. The data are consistent with standard model predictions. The mass spectrum, being a probe for new physics, is examined for new interactions of quarks and leptons from a common composite structure. Assuming a contact interaction with the conventional coupling g{sup 2}{sub 0}/4{pi}=1 , limits on chiral quark-electron and quark-muon compositeness scales in the range of 2.5 to 4.2TeV are obtained. {copyright} {ital 1997} {ital The American Physical Society}

Oxabicyclooctane-Linked Novel Bacterial Topoisomerase Inhibitors as Broad Spectrum Antibacterial Agents

Abstract: Bacterial resistance is eroding the clinical utility of existing antibiotics necessitating the discovery of new agents. Bacterial type II topoisomerase is a clinically validated, highly effective, and proven drug target. This target is amenable to inhibition by diverse classes of inhibitors with alternative and distinct binding sites to quinolone antibiotics, thus enabling the development of agents that lack cross-resistance to quinolones. Described here are novel bacterial topoisomerase inhibitors (NBTIs), which are a new class of gyrase and topo IV inhibitors and consist of three distinct structural moieties. The substitution of the linker moiety led to discovery of potent broad-spectrum NBTIs with reduced off-target activity (hERG IC50 > 18 μM) and improved physical properties. AM8191 is bactericidal and selectively inhibits DNA synthesis and Staphylococcus aureus gyrase (IC50 = 1.02 μM) and topo IV (IC50 = 10.4 μM). AM8191 showed parenteral and oral efficacy (ED50) at less than 2.5 mg/kg doses in a S....

Theoretical and Experimental Exploration of a Novel In-Plane Chemically Ordered (Cr2/3M1/3)2AlC i-MAX Phase with M = Sc and Y

Abstract: We have uncovered two inherently laminated transition metal carbides, (Cr2/3Sc1/3)2AlC and (Cr2/3Y1/3)2AlC, which display in-plane chemical order in carbide sheet and Kagome pattern in Al layer. The phases belong to the most recently discovered family of so called i-MAX phases. The materials were synthesized and the crystal structures evaluated by means of analytical high resolution scanning transmission electron microscopy, selected area electron diffraction, and X-ray diffraction Rietveld refinement. An orthorhombic structure of space group Cmcm (#63) and a monoclinic structure of space group C2/c (#15) are solved. The compounds were investigated by first principles calculations based on density functional theory, suggesting close to degenerate antiferro- and ferromagnetic spin states, dynamical and mechanical stability, and a Voigt bulk modulus in the range 134-152 GPa.

Effect of selected atomic layer deposition parameters on the structure and dielectric properties of hafnium oxide films

Abstract: HfO2 films were atomic layer deposited from HfCl4 and H2O on Si(100) in the temperature range of 226–750°C. The films consisted of dominantly the monoclinic polymorph. Elastic recoil detection analysis revealed high residual chlorine and hydrogen contents (2–5at.%) in the films grown below 300–350°C. The content of residual hydrogen and chlorine monotonously decreased with increasing growth temperature. The effective permittivity insignificantly depended on the growth temperature and water partial pressure. Capacitance-voltage curves exhibited marked hysteresis especially in the films grown at 400–450°C, and demonstrated enhanced distortions likely due to the increased trap densities in the films grown at 700–750°C. Changes in water pressure led to some changes in the extent of crystallization, but did not induce any clear changes in the capacitance of the dielectric layer.

Atomistic Insights into the Oriented Attachment of Tunnel-Based Oxide Nanostructures

Abstract: Controlled synthesis of nanomaterials is one of the grand challenges facing materials scientists. In particular, how tunnel-based nanomaterials aggregate during synthesis while maintaining their well-aligned tunneled structure is not fully understood. Here, we describe the atomistic mechanism of oriented attachment (OA) during solution synthesis of tunneled α-MnO2 nanowires based on a combination of in situ liquid cell transmission electron microscopy (TEM), aberration-corrected scanning TEM with subangstrom spatial resolution, and first-principles calculations. It is found that primary tunnels (1 × 1 and 2 × 2) attach along their common {110} lateral surfaces to form interfaces corresponding to 2 × 3 tunnels that facilitate their short-range ordering. The OA growth of α-MnO2 nanowires is driven by the stability gained from elimination of {110} surfaces and saturation of Mn atoms at {110}-edges. During this process, extra [MnOx] radicals in solution link the two adjacent {110} surfaces and bond with the u...

Gene set enrichment analysis: A knowledge-based approach for interpreting genome-wide expression profiles

Abstract: Although genomewide RNA expression analysis has become a routine tool in biomedical research, extracting biological insight from such information remains a major challenge. Here, we describe a powerful analytical method called Gene Set Enrichment Analysis (GSEA) for interpreting gene expression data. The method derives its power by focusing on gene sets, that is, groups of genes that share common biological function, chromosomal location, or regulation. We demonstrate how GSEA yields insights into several cancer-related data sets, including leukemia and lung cancer. Notably, where single-gene analysis finds little similarity between two independent studies of patient survival in lung cancer, GSEA reveals many biological pathways in common. The GSEA method is embodied in a freely available software package, together with an initial database of 1,325 biologically defined gene sets.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.