3,731 research outputs found
Halving the Casimir force with conductive oxides
The possibility to modify the strength of the Casimir effect by tailoring the
dielectric functions of the interacting surfaces is regarded as a unique
opportunity in the development of Micro- and NanoElectroMechanical Systems. In
air, however, one expects that, unless noble metals are used, the electrostatic
force arising from trapped charges overcomes the Casimir attraction, leaving no
room for exploitation of Casimir force engineering at ambient conditions. Here
we show that, in the presence of a conductive oxide, the Casimir force can be
the dominant interaction even in air, and that the use of conductive oxides
allows one to reduce the Casimir force up to a factor of 2 when compared to
noble metals.Comment: modified version, accepted for publication in Phys Rev Let
Fiber-top atomic force microscope
We present the implementation of an atomic force microscope (AFM) based on fiber-top design. Our results demonstrate that the performances of fiber-top AFMs in contact mode are comparable to those of similar commercially available instruments. Our device thus represents an interesting\ud
alternative to existing AFMs, particularly for applications outside specialized research laboratories, where a compact, user-friendly, and versatile tool might often be preferred
Interplay between antiferromagnetic order and spin polarization in ferromagnetic metal/electron-doped cuprate superconductor junctions
Recently we proposed a theory of point-contact spectroscopy and argued that
the splitting of zero-bias conductance peak (ZBCP) in electron-doped cuprate
superconductor point-contact spectroscopy is due to the coexistence of
antiferromagnetic (AF) and d-wave superconducting orders [Phys. Rev. B {\bf
76}, 220504(R) (2007)]. Here we extend the theory to study the tunneling in the
ferromagnetic metal/electron-doped cuprate superconductor (FM/EDSC) junctions.
In addition to the AF order, the effects of spin polarization, Fermi-wave
vector mismatch (FWM) between the FM and EDSC regions, and effective barrier
are investigated. It is shown that there exits midgap surface state (MSS)
contribution to the conductance to which Andreev reflections are largely
modified due to the interplay between the exchange field of ferromagnetic metal
and the AF order in EDSC. Low-energy anomalous conductance enhancement can
occur which could further test the existence of AF order in EDSC. Finally, we
propose a more accurate formula in determining the spin polarization value in
combination with the point-contact conductance data.Comment: 9 pages, 8 figure
High-Q nested resonator in an actively stabilized optomechanical cavity
Experiments involving micro- and nanomechanical resonators need to be
carefully designed to reduce mechanical environmental noise. A small scale
on-chip approach is to add an additional resonator to the system as a
mechanical low-pass filter. Unfortunately, the inherent low frequency of the
low-pass filter causes the system to be easily excited mechanically. Fixating
the additional resonator ensures that the resonator itself can not be excited
by the environment. This, however, negates the purpose of the low-pass filter.
We solve this apparent paradox by applying active feedback to the resonator,
thereby minimizing the motion with respect the front mirror of an
optomechanical cavity. Not only does this method actively stabilize the cavity
length, but it also retains the on-chip vibration isolation.Comment: Minor adjustments mad
ΠΡΡΠ½Π°Π» ΠΊΡΠΈΠΌΡΡΠΊΠΈΡ ΠΊΠ°ΡΠ°ΡΠΌΡΠ² βΠΠΈΠ·ΡΠΌ ΠΉΠΎΠ»β (βΠΠ°Ρ ΡΠ»ΡΡ β) Ρ ΡΠ²ΡΡΠ»Ρ ΡΡΠ°Π΄ΠΈΡΡΠΉ ΠΊΠ°ΡΠ°ΡΠΌΡΡΠΊΠΎΡ ΠΏΡΠ΅ΡΠΈ Ρ Π½Π°ΡΡΠΎΠ½Π°Π»ΡΠ½ΠΎΡ ΠΏΠΎΠ»ΡΡΠΈΠΊΠΈ ΠΡΠΈΠΌΡΡΠΊΠΎΡ ΠΠ Π‘Π
Π ΡΡΠ°ΡΡΠ΅ ΡΠΎΠ΄Π΅ΡΠΆΠΈΡΡΡ ΠΎΠΏΠΈΡΠ°Π½ΠΈΠ΅ ΠΊΠ°ΡΠ°ΠΈΠΌΡΠΊΠΈΡ
ΠΏΠ΅ΡΠΈΠΎΠ΄ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΠ·Π΄Π°Π½ΠΈΠΉ Π½Π°ΡΠ°Π»Π° Π₯Π₯ Π²Π΅ΠΊΠ°, ΠΈΡ
ΡΠ΅Π»Π΅ΠΉ ΠΈ Π·Π°Π΄Π°ΡΠΈ, ΠΎΠ±ΡΠ΅ΠΌΠ°, ΠΎΡΠ½ΠΎΠ²Π½ΡΡ
ΠΎΡΠ΄Π΅Π»ΠΎΠ², ΠΈΡΡΠ»Π΅Π΄ΡΠ΅ΡΡΡ ΠΎΡΡΠ°ΠΆΠ΅Π½ΠΈΠ΅ Π² ΠΊΠ°ΡΠ°ΠΈΠΌΡΠΊΠΎΠΉ ΠΏΠ΅ΡΠΈΠΎΠ΄ΠΈΠΊΠ΅ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ² Π½Π°ΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΊΡΠ»ΡΡΡΡΠ½ΠΎΠ³ΠΎ ΡΠ΅Π½Π΅ΡΡΠ°Π½ΡΠ°, ΠΈΠ·ΡΡΠ°Π΅ΡΡΡ ΡΠ²ΡΠ·Ρ ΡΡΠ½ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΠ·Π΄Π°Π½ΠΈΠΉ ΠΊΠ°ΡΠ°ΠΈΠΌΠΎΠ² Ρ ΠΎΠ±ΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎ-ΠΏΠΎΠ»ΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΆΠΈΠ·Π½ΡΡ ΠΊΠ°ΡΠ°ΠΈΠΌΡΠΊΠΎΠΉ ΠΎΠ±ΡΠΈΠ½Ρ.Π‘ΡΠ°ΡΡΡ ΠΌΡΡΡΠΈΡΡ ΠΎΠΏΠΈΡ ΠΊΠ°ΡΠ°ΡΠΌΡΡΠΊΠΈΡ
Π²ΠΈΠ΄Π°Π½Ρ ΠΏΠΎΡΠ°ΡΠΊΡ Π₯Π₯ ΡΡΠΎΠ»ΡΡΡΡ, Π·'ΡΡΠΎΠ²ΡΡ ΡΡ
Π½Ρ ΡΡΠ»Ρ Ρ Π·Π°Π²Π΄Π°Π½-Π½Ρ, ΠΎΠ±ΡΡΠ³, ΠΎΡΠ½ΠΎΠ²Π½Ρ ΡΠΎΠ·Π΄ΡΠ»ΠΈ; Π΄ΠΎΡΠ»ΡΠ΄ΠΆΡΡ Π²ΡΠ΄Π±ΠΈΡΡΡ Ρ ΠΊΠ°ΡΠ°ΡΠΌΡΡΠΊΡΠΉ ΠΏΠ΅ΡΡΠΎΠ΄ΠΈΡΡ ΠΏΡΠΎΡΠ΅ΡΡΠ² Π½Π°ΡΡΠΎΠ½Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΊΡΠ»ΡΡΡΡΠ½ΠΎΠ³ΠΎ ΡΠ΅Π½Π΅ΡΠ°Π½ΡΡ; Π²ΠΈΠ²ΡΠ°Ρ Π·Π²'ΡΠ·ΠΎΠΊ Π΅ΡΠ½ΡΡΠ½ΠΈΡ
Π²ΠΈΠ΄Π°Π½Ρ ΠΊΠ°ΡΠ°ΡΠΌΡΠ² ΡΠ· ΡΡΡΠΏΡΠ»ΡΠ½ΠΎ-ΠΏΠΎΠ»ΡΡΠΈΡΠ½ΠΈΠΌ ΠΆΠΈΡΡΡΠΌ ΠΊΠ°ΡΠ°ΡΠΌΡΡΠΊΠΎΡ Π³ΡΠΎΠΌΠ°Π΄ΠΈ.The article researches the Karaite mass media of the beginning of the XX century: its matters and tasks, volume, main sections, the reflection of the cultural renaissance in it and its connection with life of the Karaite community
Synthesis and biological evaluation of immunoconjugates of adriamycin and a human IgM linked by poly[N5-(2-hydroxyethyl)-l-glutamine
The synthesis and purification of radiolabelled immunoconjugates, composed of a human IgM monoclonal antibody (IgM 16.88) directed against an intracellular tumour-associated antigen, the drug carrier poly[N5-(2-hydroxyethyl)--glutamine] (PHEG) and the cytostatic drug adriamycin (ADR) are described. The immunoconjugates were constructed to allow selective release of ADR in the putatively acidic environment of the tumour through a novel acid-labile maleamic acid linker. The conjugate of PHEG and the acid-labile ADR derivative effectively released ADR in cytotoxic amounts at a pH of 6.0 as judged from incubation in buffer and from inhibition of the growth of HT-29 colon tumour cells in vitro. Immunoconjugates were prepared by coupling of PHEG-ADR having a hydrolytically stable amide bond with 131I-labelled antibody through thioether bond formation involving a single thiol group at the C-terminus of the polymer chain and maleimido groups introduced onto th
Casimir-like effect on a granular pile
We investigate experimentally a Casimir-like effect in a three-dimensional pile of rice, which has a power-law avalanche size distribution. We observe the change in distance between two Plexiglas sheets placed on the pile parallel to each other and parallel to the mean avalanche flow direction, while rice grains are continuously and uniformly falling on top of the pile. The resulting avalanches are fluctuations, confinement of which is found to drive the two plates together. During 25-h experimental runs, for initial intersheet distances ranging from 20.0 to 90.0 mm we observe changes in the range from 6.0 mm to less than 1.0 mm. A similar distance dependence is obtained from a simple analytical model. Β© 2010 The American Physical Society
Factors associated with ethnical disparity in overall survival for patients with hepatocellular carcinoma
Hepatocellular carcinoma (HCC) is an important cause of cancer-related death worldwide. Ethnical disparity in overall survival has been demonstrated for HCC patients in the United States (U.S.). We aimed to evaluate the contributors to this survival disparity. The SEER database was used to identify HCC patients from 2004 to 2012. Kaplan-Meier curves and Cox proportional hazard models were used to evaluate overall survival by ethnicity and the contributors to ethnical survival disparity. A total of 33 062 patients were included: 15 986 Non-Hispanic Whites, 6535 Hispanic Whites, 4842 African Americans, and 5699 Asians. Compared to Non-Hispanic Whites, African Americans had worse survival (HR, 1.18; 95%CI, 1.14-1.23), while Asians had a better survival (HR, 0.85; 95%CI, 0.82-0.89), and Hispanic Whites had a similar survival (HR, 1.01; 95%CI, 0.97-1.05). Multivariate Cox analysis identified that tumor presentation- and treatment-related factors significantly contributed to the ethnical survival disparity. Especially, tumor size was the most important contributor (HR, 1.11; 95%CI, 1.07-1.16). There is no ethnical survival disparity in patients undergoing liver transplantation and sub-analysis of patients within the Milan criteria for liver transplantation demonstrated no significant survival disparity between African Americans and non-Hispanic Whites in transplantation adjustment analysis (HR, 1.23; 95%CI, 1.11-1.35 in non-adjustment analysis to HR, 1.05; 95%CI, 0.95-1.15 after adjustment). Finally, no important contributor to the superior overall survival in Asians was identified. In conclusion, poor tumor presentation at diagnosis, limited benefit from resection and restricted utilization of liver transplantation are important contributors to poorer survival of African Americans with HCC
The Critical Behaviour of the Spin-3/2 Blume-Capel Model in Two Dimensions
The phase diagram of the spin-3/2 Blume-Capel model in two dimensions is
explored by conventional finite-size scaling, conformal invariance and Monte
Carlo simulations. The model in its -continuum Hamiltonian version is
also considered and compared with others spin-3/2 quantum chains. Our results
indicate that differently from the standard spin-1 Blume-Capel model there is
no multicritical point along the order-disorder transition line. This is in
qualitative agreement with mean field prediction but in disagreement with
previous approximate renormalization group calculations. We also presented new
results for the spin-1 Blume-Capel model.Comment: latex 18 pages, 4 figure
Patient to patient hepatitis B transmission during heart biopsy procedures. A report of a European Working Party on Viral Hepatitis in Heart Transplant Recipients.
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