Publications by authors named "Long Q Chen"

Article Synopsis
  • Ultrafast stimuli can create stable states of matter that can't be achieved under normal conditions, highlighting the need to understand the relationship between ultrafast processes and these states.
  • The study uses advanced optical and X-ray techniques to observe how a polar vortex supercrystal forms in a specially designed material when it's excited by light, demonstrating various phases in just a few picoseconds.
  • Over time, fluctuations in the structure of the supercrystal are gradually eliminated, leading to the stable formation of a single vortex supercrystal phase, with theoretical models supporting these observations.
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Epitaxial oxide ferroelectric films exhibit emerging phenomena arising from complex domain configurations even at pseudoequilibrium, including the creation of domain states unfavored in nature and abrupt piezoelectric coefficients around morphotropic phase boundaries. The nanometer-sized domain configurations and their domain switching dynamics under external stimuli are directly linked to the ultrafast manipulation of ferroelectric thin films; however, complex domain switching dynamics under homogeneous electric fields has not been fully explored, especially at the nanosecond timescale. This Letter reports the nanosecond dynamics of ferroelastic-domain switching from the 90° to 180° direction using time-resolved x-ray microdiffraction under homogeneous electric fields onto an epitaxial Pb(Zr_{0.

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A simple and inexpensive technique for the simultaneous fabrication of positive (i.e., protruding), very high aspect (>10) ratio nanostructures together with micro- or millistructures is developed.

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Background: BRCA1 and BRCA2 account for the majority of the known familial breast cancer risk, however, the impact of other cancer susceptibility genes largely remains to be elucidated. Checkpoint Kinase 2 (CHEK2) is an important signal transducer of cellular responses to DNA damage, whose defects have been associated with an increase in breast cancer risk. Previous studies have identified low penetrance CHEK2 alleles such as 1100delC and I157T, as well as variants such as S428F in the Ashkenazi Jewish population and IVS2 + 1G>A in the Polish population.

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Checkpoint kinase 2 (CHEK2) is a protein involved in arresting cell cycle in response to DNA damage. To investigate whether it plays an important role in the development of prostate cancer (PRCA) in the Ashkenazi Jewish (AJ) population, we sequenced CHEK2 in 75 AJ individuals with prostate, breast, or no cancer (n=25 each). We identified seven coding SNPs (five are novel) that changed the amino-acid sequence, resulting in R3W, E394F, Y424H, S428F, D438Y, P509S, and P509L.

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Attempts at heavy edge over-etching of a single thin film under a photoresist to leave behind a residual smaller patterned line as a mask for nanostructure fabrication frequently fail due to detachment of the photoresist above it. We have accordingly developed a technique named 'residual pattern of double thin-film over-etching' (RDTO) to obtain a nanoscale residual pattern of the bottom thin film after extensive edge over-etching. When Au and Cr were used as the top and bottom thin films, respectively, heavy over-etching of Cr for use as a mask for nanopatterning of the underlying silicon substrate was feasible.

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