•The properties of Si and N doped diamond-like carbon (Si–N–DLC) have been examined.•The internal stress on Si–N–DLC was lower than that on N doped DLC.•The optical bandgap of Si–N–DLC showed an ...increasing trend with increasing N content.•Si–N–DLC/p-type Si junctions annealed in a vacuum showed rectifying characteristics.
We have investigated the effects of silicon (Si) doping on the chemical bonding states and the electrical, optical, and mechanical properties of nitrogen-doped diamond-like carbon (N−DLC) films prepared via plasma-enhanced chemical vapor deposition using hydrogen as a dilution gas. N doping accelerated the formation of clustered sp2 C in N−DLC films, whereas the clustering was almost suppressed in Si and N doped DLC (Si−N−DLC) films. Sp3 C sites in the Si–N–DLC films were higher than those in the N–DLC films. For the Si−N−DLC films, sp3 C-N bonds were preferentially formed compared with the sp2 C=N bonds. The internal stress on the Si−N−DLC films was lower than that on the N−DLC films. The Si−N−DLC films exhibited higher optical bandgaps than the N−DLC films. As the N2 flow ratio increased, the optical bandgap of the Si−N−DLC films showed an increasing trend, whereas that of the N−DLC films showed an opposite trend. The current−voltage characteristics of Si−N−DLC/p-type Si heterojunctions were not rectifying; however, after postdeposition annealing, the heterojunctions exhibited rectifying characteristics.
Gene therapy promises to treat diseases that arise from genetic abnormalities by correcting the underlying cause of the disease rather than treating the associated symptoms. Successful transfer of ...nucleic acids into cells requires efficient delivery vehicles that protect the cargo and can penetrate the appropriate cellular barriers before releasing their contents. Many viral vectors and synthetic polycationic vectors for nucleic acid delivery do not translate well from in vitro to in vivo applications due to their instability and toxicity. We synthesized and characterized a library of biocompatible low charge density polymers from a family of poly(amine- co-ester) (PACE) terpolymers produced via enzyme catalyzed polymerization. PACE polymers are highly customizable; we found that the terpolymer composition can be optimized to produce efficient transfection of various nucleic acids-including DNA plasmids, mRNA, and siRNA-in specific cell types with low toxicity. Our findings suggest that the unique tunability of PACEs offers new tools for gene therapy and other biomedical applications.
A
bstract
Charged lepton flavor violation is forbidden in the Standard Model but possible in several new physics scenarios. In many of these models, the radiative decays
τ
±
→
ℓ
±
γ
(
ℓ
=
e, μ
) are ...predicted to have a sizeable probability, making them particularly interesting channels to search at various experiments. An updated search via
τ
±
→
ℓ
±
γ
using full data of the Belle experiment, corresponding to an integrated luminosity of 988 fb
−
1
, is reported for charged lepton flavor violation. No significant excess over background predictions from the Standard Model is observed, and the upper limits on the branching fractions,
B
(
τ
±
→
μ
±
γ
) ≤ 4
.
2 × 10
−
8
and
B
(
τ
±
→
e
±
γ
) ≤ 5
.
6 × 10
−
8
, are set at 90% confidence level.
We have deposited silicon-incorporated diamond-like carbon (Si-DLC) films by plasma-enhanced chemical vapor deposition using monomethylsilane (CH3SiH3; MMS) as a Si source, and systematically ...investigated the impacts of substrate bias and dilution gas on the mechanical and tribological properties of the Si-DLC films. The use of a pulse bias and hydrogen dilution is very effective in suppressing the generation of particles during the deposition. The internal stress of the Si-DLC films deposited using the pulse bias tended to be lower than that of the Si-DLC films deposited using a DC bias, while the hydrogen dilution resulted in the increase in the internal stress. On the other hand, the Si-DLC film deposited with H2 using the pulse bias showed the highest adhesion strength and the lowest friction coefficient. The use of the pulse bias resulted in the increase in the wear resistance.
•Effects of substrate bias and dilution gas on the properties of Si-DLC films have been investigated.•The Si-DLC film prepared using a pulse bias with H2 presents the highest adhesion strength.•The Si-DLC film prepared using a pulse bias with H2 shows the lowest friction coefficient.
We have grown aluminum nitride (AlN) films on Si(110) substrates by pulsed laser deposition (PLD), and investigated the effects of laser power on the crystallinity and surface morphology of the AlN ...films. First, we epitaxially grew a fairly flat, high-quality AlN film, which contained no rotation domains, onto the Si(110) substrate in a well-lattice-matched relationship. Secondly, we formed a SiC interfacial buffer layer on the AlN film to grow a high-quality 3C-SiC film on the SiC buffer layer by PLD, which gave rise to a 3C-SiC(111)3×3 surface. The root-mean-square-roughness value of the SiC film was smaller than the previously reported values of SiC/AlN multilayers on Si(100) and Si(111) substrates. Thirdly, we grew graphene by annealing the SiC film at a high temperature in an ultra-high vacuum. It was demonstrated that the qualified graphene layer without rotation domains was grown on the SiC film. The formation of voids and the outdiffusion of Al and N atoms from the AlN film were successfully suppressed during the high-temperature annealing.
•A graphene layer is grown epitaxially on SiC/AlN/Si(110).•AlN films are grown epitaxially on Si(110) substrate in a well-lattice-matched relationship.•AlN films contain no rotation domains.•A SiC film is grown on a SiC buffer layer, which gives rise to a 3C-SiC(111)3×3 surface.
An extensive outbreak of staphylococcal food poisoning occurred in Kansai district in Japan. As many as 13 420 cases frequently ingested dairy products manufactured by a factory in Osaka City. The ...main ingredient of these dairy products was powdered skim milk manufactured by a factory in Hokkaido. Staphylococcal enterotoxin A (SEA) (≤0·38 ng/ml) was detected in low-fat milk and approx. 3·7 ng/g in powdered skim milk. The total intake of SEA per capita was estimated mostly at approx. 20-100 ng. The assumed attack rate was considerably lower than those reported in previous outbreaks. SEA exposed at least twice to pasteurization at 130 °C for 4 or 2 s retained both immunological and biological activities, although it had been partially inactivated. The present outbreak was unusual in that the thermal processes had destroyed staphylococci in milk but SEA had retained enough activity to cause intoxication.
We search for lepton-flavor-violating τ→ℓV0 decays, where ℓ is an electron or muon and V0 is one of the vector mesons ρ0, ϕ, ω, K⁎0 and K¯⁎0. We use 854 fb−1 of data collected with the Belle detector ...at the KEKB asymmetric-energy e+e− collider. No evidence for a signal is found in any decay mode, and we obtain 90% confidence level upper limits on the individual branching fractions in the range (1.2–8.4)×10−8.
Using 605 fb(-1) of data collected at the Upsilon(4S) resonance we present a measurement of the inclusive radiative B-meson decay channel, B-->X(s)gamma. For the lower photon energy thresholds of ...1.7, 1.8, 1.9, and 2.0 GeV, as defined in the rest frame of the B meson, we measure the partial branching fraction and the mean and variance of the photon energy spectrum. At the 1.7 GeV threshold we obtain the partial branching fraction BF(B-->X(s)}gamma)=(3.45+/-0.15+/-0.40)x10(-4), where the errors are statistical and systematic.
We have deposited Si-doped DLC (Si-DLC) multilayer films by plasma-enhanced chemical vapor deposition (PECVD) using an intermittent supply of monomethylsilane (SiH3CH3; MMS) as the Si source. The ...mechanical and tribological properties of the multilayer films were compared with those of Si-DLC single-layer films. The internal stress decreased as the Si content increased. It was found that the internal stress values of the multilayer films were lower than those of the single-layer films. Scratch tests demonstrated that the multilayer films had higher adhesion strength than the single-layer films owing to the further reduction of the internal stress. We found that the multilayer films with low Si content presented low friction while maintaining the wear performance. Specifically, the multilayer film containing ~2at.% Si showed a friction coefficient less than 0.08, while the addition of ~11at.% Si to the single-layer film was required for obtaining such a low friction coefficient. The wear rate increased with increasing Si content. In the case of the above two films, the single-layer film had a specific wear about rate two times higher than that of the multilayer film.
•The stresses of multilayer films were lower than those of single-layer films.•Multilayer films had higher adhesion strength than single-layer films.•Multilayer films showed better tribological properties than single-layer films.
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