211 research outputs found
Rotation of the pinning direction in the exchange bias training effect in polycrystalline NiFe/FeMn bilayers
For polycrystalline NiFe/FeMn bilayers, we have observed and quantified the rotation of the pinning direction in the exchange bias training and recovery effects. During consecutive hysteresis loops, the rotation of the pinning direction strongly depends on the magnetization reversal mechanism of the ferromagnet layer. The interfacial uncompensated magnetic moment of antiferromagnetic grains may be irreversibly switched and rotated when the magnetization reversal process of the ferromagnet layer is accompanied by domain wall motion and domain rotation, respectively
Interacting Electrons on a Fluctuating String
We consider the problem of interacting electrons constrained to move on a
fluctuating one-dimensional string. An effective low-energy theory for the
electrons is derived by integrating out the string degrees of freedom to lowest
order in the inverse of the string tension and mass density, which are assumed
to be large. We obtain expressions for the tunneling density of states, the
spectral function and the optical conductivity of the system. Possible
connections with the phenomenology of the cuprate high temperature
superconductors are discussed.Comment: 14 pages, 1 figur
Relationship between HPV16/18 E6 and р53, р21waf1, MDM2, Ki67 and cyclin D1 expression in esophageal squamous cell carcinoma: comparative study by using tissue microarray technology
Aim: To investigate the role of human papillomavirus (HPV) HPV16/18 E6 oncogene in the carcinogenesis of esophageal cell carcinoma (ESCC). Materials and Methods: Tissue microarray (TMA) block was constructed from 60 cases of paraffin-embedded ESCC tissues and pair-matched controls (adjacent normal epithelium). Immunohistochemistry (IHC) methods were applied to detect the expression of HPV16/18 E6, p53, p21Waf1, MDM2, Ki67 and cyclin D1 proteins on TMA slides. In situ hybridization (ISH) targeting HPV gene was also used. Results: In ESCC samples, 18.3% (11/60) were revealed HPV16/18 E6 positive by IHC, while 40.0% (24/60) HPV positive by ISH; HPV16/18 E6 expression was significantly higher than that of control samples. In ESCC samples, the expressions of p53, p21Waf1, Cyclin D1, MDM2 and Ki67 were recorded in 60.0% (36/60), 40.0% (24/60), 51.7% (31/60), 65.0% (39/60) and 88.3% (53/60) cases respectively, In ESCC samples, p53, MDM2 and Ki67 expression correlated with the HPV16/18 E6 expression (p < 0.01), p21Waf1 expression — with these of MDM2 and cyclin D1 (p < 0.01) whilst expression of Ki67 — with ESCC grade (p < 0.01). Conclusion: HPV might be one of etiological factor of esophageal carcinoma in Shantou, China. p53, MDM2 proteins may play important roles in the pathogenesis of HPV-associated ESCC.Цель: исследовать роль онкогена HPV16/18 E6 вируса папилломы человека (HPV) в развитии плоскоклеточной карциномы
пищевода (ESCC). Материалы и методы: исследованы 60 образцов ESCC и контрольные образцы нетрансформированной
ткани (парафиновые блоки). Для выявления экспрессии белков HPV16/18 E6, p53, p21Waf1, MDM2, Ki67 и циклина D1 в срезах
для тканевых микрочипов (tissue microarray, TMA) применен метод иммуногистохимии (IHC), для определения экспрессии
генов HPV применяли гибридизацию in situ (ISH). Результаты: методами IHC, экспрессия HPV16/18 E6 выявлена в 18,3%
(11/60) случаев ESCC, в то время как по результатам метода ISH, 40,0% (24/60) образцов признаны HPV-позитивными.
В образцах ESCC экспрессия p53, p21Waf1, циклина D1, MDM2 и Ki67 выявлена в 60,0% (36/60), 40,0% (24/60), 51,7% (31/60),
65,0% (39/60) и 88,3% (53/60) случаев соответственно, причем экспрессия p53, MDM2 и Ki67 коррелировала с экспрессией
HPV16/18 E6 (p < 0,01), экспрессия p21Waf1 — с таковой MDM2 и циклина D1, а экспрессия Ki67 — со стадией развития
опухоли (p < 0.01). Выводы: HPV может являться одним из этиологических факторов развития рака пищевода в провинции
Шанту, Китай. Белки p53 и MDM2 могут принимать участие в патогенезе плоскоклеточного рака пищевода, ассоциированного
с вирусом папилломатоза
Quantifying atmospheric nitrogen deposition through a nationwide monitoring network across China
A Nationwide Nitrogen Deposition Monitoring Network (NNDMN) containing 43 monitoring sites was established in China to measure gaseous NH3, NO2, and HNO3 and particulate NH4+ and NO3− in air and/or precipitation from 2010 to 2014. Wet/bulk deposition fluxes of Nr species were collected by precipitation gauge method and measured by continuous-flow analyzer; dry deposition fluxes were estimated using airborne concentration measurements and inferential models. Our observations reveal large spatial variations of atmospheric Nr concentrations and dry and wet/bulk Nr deposition. On a national basis, the annual average concentrations (1.3–47.0 μg N m−3) and dry plus wet/bulk deposition fluxes (2.9–83.3 kg N ha−1 yr−1) of inorganic Nr species are ranked by land use as urban > rural > background sites and by regions as north China > southeast China > southwest China > northeast China > northwest China > Tibetan Plateau, reflecting the impact of anthropogenic Nr emission. Average dry and wet/bulk N deposition fluxes were 20.6 ± 11.2 (mean ± standard deviation) and 19.3 ± 9.2 kg N ha−1 yr−1 across China, with reduced N deposition dominating both dry and wet/bulk deposition. Our results suggest atmospheric dry N deposition is equally important to wet/bulk N deposition at the national scale. Therefore, both deposition forms should be included when considering the impacts of N deposition on environment and ecosystem health
Wafer-scale selective area growth of GaN hexagonal prismatic nanostructures on c-sapphire substrate
Selective area growth of GaN nanostructures has been performed on full 2"
c-sapphire substrates using Si3N4 mask patterned by nanoimprint lithography
(array of 400 nm diameter circular holes). A new process has been developed to
improve the homogeneity of the nucleation selectivity of c-oriented hexagonal
prismatic nanostructures at high temperature (1040\circ C). It consists of an
initial GaN nucleation step at 950 \circ C followed by ammonia annealing before
high temperature growth. Structural analyses show that GaN nanostructures are
grown in epitaxy with c-sapphire with lateral overgrowths on the mask. Strain
and dislocations are observed at the interface due to the large GaN/sapphire
lattice mismatch in contrast with the high quality of the relaxed crystals in
the lateral overgrowth area. A cathodoluminescence study as a function of the
GaN nanostructure size confirms these observations: the lateral overgrowth of
GaN nanostructures has a low defect density and exhibits a stronger near band
edge (NBE) emission than the crystal in direct epitaxy with sapphire. The shift
of the NBE positions versus nanostructure size can be mainly attributed to a
combination of compressive strain and silicon doping coming from surface mask
diffusion
Direct Measurements of the Branching Fractions for and and Determinations of the Form Factors and
The absolute branching fractions for the decays and
are determined using singly
tagged sample from the data collected around 3.773 GeV with the
BES-II detector at the BEPC. In the system recoiling against the singly tagged
meson, events for and events for decays are observed. Those yield
the absolute branching fractions to be and . The
vector form factors are determined to be
and . The ratio of the two form
factors is measured to be .Comment: 6 pages, 5 figure
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
BESII Detector Simulation
A Monte Carlo program based on Geant3 has been developed for BESII detector
simulation. The organization of the program is outlined, and the digitization
procedure for simulating the response of various sub-detectors is described.
Comparisons with data show that the performance of the program is generally
satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM
Measurement of branching fractions for the inclusive Cabibbo-favored ~K*0(892) and Cabibbo-suppressed K*0(892) decays of neutral and charged D mesons
The branching fractions for the inclusive Cabibbo-favored ~K*0 and
Cabibbo-suppressed K*0 decays of D mesons are measured based on a data sample
of 33 pb-1 collected at and around the center-of-mass energy of 3.773 GeV with
the BES-II detector at the BEPC collider. The branching fractions for the
decays D+(0) -> ~K*0(892)X and D0 -> K*0(892)X are determined to be BF(D0 ->
\~K*0X) = (8.7 +/- 4.0 +/- 1.2)%, BF(D+ -> ~K*0X) = (23.2 +/- 4.5 +/- 3.0)% and
BF(D0 -> K*0X) = (2.8 +/- 1.2 +/- 0.4)%. An upper limit on the branching
fraction at 90% C.L. for the decay D+ -> K*0(892)X is set to be BF(D+ -> K*0X)
< 6.6%
- …