Search Results - (Author, Cooperation:Y. C. Li)

2018-06-20

BMJ Publishing

2044-6055

Medicine

Open access, Complementary medicine

2011-06-28

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Amino Acid Transport Systems, Basic/genetics ; Base Sequence ; Camptothecin/pharmacology ; Canavanine/pharmacology ; DNA Breaks ; DNA Topoisomerases, Type I/*metabolism ; DNA, Fungal/chemistry/*metabolism ; DNA, Single-Stranded/metabolism ; Microsatellite Repeats ; Molecular Sequence Data ; *Mutagenesis ; Nucleic Acid Conformation ; Ribonuclease H/genetics/metabolism ; Ribonucleotides/*metabolism ; Saccharomyces cerevisiae/enzymology/*genetics/*metabolism ; Saccharomyces cerevisiae Proteins/genetics ; *Sequence Deletion ; Transcription, Genetic

2015-12-04

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

2018-10-31

Institute of Physics (IOP)

1755-1307

1755-1315

Geography

Geosciences

Physics

2018-11-06

Institute of Physics (IOP)

1755-1307

1755-1315

Geography

Geosciences

Physics

2018-11-16

American Physical Society (APS)

0031-9007

1079-7114

Physics

Condensed Matter: Electronic Properties, etc.

2018-08-03

Institute of Physics (IOP)

1757-8981

1757-899X

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

2018-11-09

American Physical Society (APS)

1050-2947

1094-1622

Physics

Fundamental concepts

2018-07-31

Institute of Physics (IOP)

1755-1307

1755-1315

Geography

Geosciences

Physics

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A microcomputer-aided ultrasonic system that can be used to measure the vibratory displacements of an object is presented. A pair of low cost 40-kHz ultrasonic transducers is used to transmit ultrasound toward an object and receive the ultrasound reflected from the object. The relative motion of the object modulates the phase angle difference between the transmitted and received ultrasound signals. A single-chip microcomputer-based phase detector was designed to record and analyze the phase shift information which is then sent to a PC-AT microcomputer for processing. We have developed an ingenious method to reconstruct the relative motion of an object from the acquired data of the phase difference changes. A digital plotter based experiment was also designed for testing the performance of the whole system. The measured accuracy of the system in the reported experiments is within ±0.4 mm and the theoretical maximal measurable speed of the object is 89.6 cm/s. The main advantages of this ultrasonic vibration measurement system are high resolution, low cost, noncontact measurement and it is easily installed.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

An overlayer system composed of a thin film on the top of a semi-infinite substrate was studied in this work for electron inelastic interactions. Analytical expressions for the depth-dependent inelastic differential and integral inverse mean free paths were derived for both incident and escaping electrons. The interface (film-substrate) effect and the surface (vacuum-film) effect were analyzed by comparing the results of an overlayer system and a semi-infinite system. It was found that the interface effect extended to several angstroms on both sides of the interface for a 500 eV electron incident into or escaping from the vacuum–SiO2–Si and the vacuum–Au–Ni systems. An application of the spatial-varying inelastic differential inverse mean free paths was made by Monte Carlo simulations of the electron elastic backscattering from an overlayer system. Good agreement was found between results calculated presently and data measured experimentally on the elastic reflection coefficient. © 1999 American Institute of Physics.

Electronic Resource

1365-3083

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The monoclonal antibody MoAb-VκIIIb binds a cross-reactive idiotopic (CRI) determinant on light (L) chains encoded by the VκIIIb subgroup A27a (Humkv325) gene segment. The aim of this study was to localize the MoAb-VκIIIb CRI. Mutational analyses involving region exchanges between a CRI-positive VκIIIb chain and a CRI-negative Vκ1 chain indicate that the MoAb-VκIIIb CRI is located in framework region (FR) 3 of A27a (Humkv325) encoded L chains. CRI-positive kappa chains unpaired with a heavy (H) chain are reactive with MoAb-VκIIIb, indicating that the CRI is located on the kappa chain alone without involvement of H chain residues. Combinatorial antibodies composed of non-parental L and H chain pairings are reactive with MoAb-VκIIIb only when the L chain is A27a (Humkv325) encoded. The CRI, therefore, is not readily perturbed by H chain interactions. When the FR3 from a CRI-positive kappa chain replaced the FR3 in a CRI-negative lambda chain, the determinant was no longer detectable with MoAb-VκIIIb. It is possible, therefore, to exchange regions between kappa chains from different families and retain the CRI structure, however the determinant is lost when placed in a more foreign background such as a lambda chain. These data more precisely define the interaction between MoAb-VκIIIb and its CRI, and indicate that there are limits within which antibody FRs can be shuffled and still retain their native structural features.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Improved methods for obtaining, preparing, and staining fish chromosomes are described. Included are procedures for resolving serial or G-type bands. A brief review of various metaphase banding procedures and their use in fishes is also presented.

Electronic Resource

1365-246X

Blackwell Publishing Journal Backfiles 1879-2005

Geosciences

The objective of this paper is to improve gravimetric terrain corrections by: (1) investigating the effect of different topographic representations that are suitable for efficient processing of high volumes of data (e.g. the mass prism and the mass line models) on terrain corrections and on geiod computations; (2) accelerating the convergence of fast Fourier transform (FFT)-based terrain-correction formulae; and (3) developing a set of new formulae corresponding to the mass prism topographic model, which can be evaluated efficiently with the 2-D FFT.Terrain corrections were computed on a grid of 600 by 600 points with spacing 30″ by 60″ in the Rocky Mountains of British Columbia, Canada. the effect of using the mass line model instead of the mass prism model is 7.4 mGal (maximum) and 0.7mGal (rms) on the terrain corrections, and 24cm (maximum) and 16cm (rms) on the geoid undulations. the optimizations made on the FFT-based terrain-correction formulae effectively speed up the convergence. the newly developed mass prism terrain-correction formula significantly reduced the required computer time and provided identical results with those from the rigorous numerical integration. On an IBM/RISC machine running AIX, the computation of the 15 convolutions (the matrix size was expanded to 1200 by 1200 after 100 per cent zero-padding) via the new formulae only took 15 min (user time), while the numerical summation method required 83.5 days.

Electronic Resource

0378-1119

Recombinant DNA ; cryptic promoters ; electroporation ; reporter gene ; transient gene expression

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

0275-1062

Stars: neutron star - quark matter

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

1365-3083

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The monoclonal anti-idiotopic antibodies LCI and 9G4 bind two non-overlapping sets of VH4 encoded antibodies. 9G4 exclusively binds VH4–21 encoded antibodies, while LCI binds antibodies derived from VH4 family gene segments V71-2, V71-4, VH4-18, VH72-I and V2-1. The VH4–21 gene segment is utilized by most cold agglutinin (CA) antibodies with I/i specificity, while antibodies encoded by other VH4 gene segments are associated not with CA disease, but primarily with rheumatoid-factor (RF) activity.We previously determined that the idiotope to which 9G4 binds in VH4-21-derived antibodies is located in framework region l (FR1). In the present study, by using mutational analysis involving individual framework- and complementarity-determining region exchanges between VH4-2I- and V71-2-encoded antibodies, we have found that the idiotope to which LCI binds in V71-2-derived antibodies also maps to FR1. The LC1 idiotope is heavy (H)-chain associated, but requires pairing with a light (L) chain for LCI binding. Recombinant antibodies composed of a variety of kappa (k) and lambda L chains paired with either a V71-2 or VH4–21 chain were produced in the baculovirus expression system. LCI bound all of the k-containing antibodies but did not bind the V71-2-encoded H chain alone nor to the two A-containing antibodies. This experiment demonstrates that not all light chains exert equivalent influence on the conformation of the H-chain idiotope. These results indicate that the FR1 of VH4-encoded antibodies is immunogenic and suggest a physiological role of FR l during an immune response.

Electronic Resource

1432-2153

Detonation ; Shock wave ; Heterogeneous combustion ; Dust explosion ; Supersonic combustion ; Unsteady flame

Springer Online Journal Archives 1860-2000

Physics

Technology

Abstract The roles which dust layers play in severe dust explosions were investigated in a 70 m long and 30 cm inside diameter horizontal Flame Acceleration Tube (FAT) with one end closed and the other end open to the atmosphere. A variety of dusts such as corn dust, cornstarch, Mira Gel starch, wheat dust, and wood flour were layered on the bottom half of the FAT. To initiate the combustion process, a detonation tube filled with a stoichiometric H2/O2 mixture at room temperature and 1 atm pressure was used to ignite a short presuspended dust cloud with a dust concentration of 500–600 g/m3. Combustion waves generated by this dust cloud travel toward the open end of the FAT and are continuously fueled by the dust/air mixtures. Flame propagation processes in the FAT were closely monitored by a variety of measuring instruments at different locations. The study demonstrates that stable quasi-detonation were reached in some runs, but self-sustained Chapman-Jouguet detonations were not observed possibly due to the limitation of the tube length. Attempts were made to determine the structure of dust detonations fueled by a dust layer. Preliminary evidence indicates that for Mira Gel starch the leading shock is essentially a triple shock configuration which involves a Mach stem and for wheat and wood dusts there possibly exists a multi-headed spin structure.

Electronic Resource

1432-2242

Key words Natural selection ; Microecological diversity ; Microsatellites ; Adaptation ; T. dicoccoides ; Wild emmer wheat

Springer Online Journal Archives 1860-2000

Biology

Abstract  Genetic diversity at 28 microsatellite loci was studied in a natural population of Triticum dicoccoides at the Ammiad microsite, north of the Sea of Galilee, Israel. This microsite was subdivided into four major habitats, North, Valley, Ridge and Karst, and further subdivided into nine subhabitats. The units thus defined showed strong and highly significant differentiation in ecological factors; in particular with respect to cover, proximity and height of rocks, and surface soil moisture after early rains. The results showed that allele distributions at microsatellite loci were nonrandom and associated with habitats. Significant genetic differentiation and variation in repeat number were found among subpopulations in the four major habitats and nine subhabitats. Habitat-specific and -unique alleles and linkage disequilibria were observed in the Karst subpopulation. The subpopulations dwelling in drier habitats and subhabitats showed higher genetic diversities at microsatellite loci. These results suggest that natural selection, presumably through aridity stress, acts upon microsatellite divergence predominantly on noncoding sequences, thereby contributing to differences in fitness.

Electronic Resource

1432-2242

Key words Genetic diversity ; Edaphic selection ; Microsatellite ; Microsite divergence ; Wild emmer wheat ; Triticum dicoccoides

Springer Online Journal Archives 1860-2000

Biology

Abstract  Twenty eight microsatellite markers were used to analyze genetic divergence in tandem dinucleotide repeated DNA regions between two edaphic subpopulations of Triticum dicoccoides growing on the contrasting terra rossa and basalt soilsfrom a microsite at Tabigha, north of the Sea of Galilee, Israel. The terra rossa soil niche was drier and more stressful than the basalt throughout the growing season (November to May). Significant microsatellite divergence in allele distribution, repeat length, genetic diversity, and linkage disequilibria were found between emmer wheat from the two soil types over two short transects of 100 m each. Soil-specific and -unique alleles and linkage disequilibria were observed in the terra rossa and basalt subpopulations. A permutation test showed that the effects of random genetic drift were very low for the significant genetic diversity at microsatellite loci between the two subpopulations, suggesting that an adaptive molecular pattern derived by edaphic selection may act upon variation of the microsatellites.

Electronic Resource