1,100 research outputs found
Observation of Seeding Effects on Fat Bloom of Dark Chocolate
Surface microstructures and polymorphism of seeded dark chocolate were observed with cryo-SEM, to clarify the effects of seeding on fat bloom stability of dark chocolate. Two thermal tests, cycling between 32 adn 20C (32/20) and 38 and 20 C (38/20), were applied to examine the fat bloom stability of the chocolate. We used three crystalline powders: Form VI of cocoa butter; the most stable B1 form of SOS (1,3-distearoyl-2-oleoylglycerol); and the second stable B2 form of BOB (1,3,-dibehenoyl-2-oleoylglycerol) as seed materials. Seeding with cocoa butter (Form VI) and SOS (B1) at concentrations of 0.5 ~ 1 wt. % showed good fat bloom stability in the 32/20 test. In the case of the 38/20 test, however, fat bloom was not prevented. Seeding with BOB (B2) gave the best fat bloom stability in both thermo-cycles; in particular, 5 wt.% BOB (B2) completely prevented fat bloom after the 38/20 test
Fat Polymorphism and Crystal Seeding Effects on Fat Bloom Stability of Dark Chocolate
The effects of seeding with fine crystal powders on the physical properties of dark chocolate are re viewed in terms of the polymorphism and crystallization behavior of cocoa butter (CBJ and of its major fat constituents. The polymorphic structure of four symmetric mixed acids saturated -oleic-saturated (Sat-0- Sat) triacylglycerols (TAGs I [POP (1 ,3-dipalmitoyl-2- oleoyl-glyceroll ;SOS I 1 ,3-distearoyl-2-oleoyl-glycerol); AOA (1 ,3-diarachidoyl-2-oleoyl-glycerol); and BOB 11 ,3-dibehenoyl-2-oleoyl-glyceroi)J. and of tristearoylglycerol (SSSI are briefly explained. An attempt is made at replacing the currently used tempering meth ~ ad in the chocolate solidification process, by a simple cooling technique using fat seed crystals. CB (form VI). SOS 1/i11. BOB (pseudo-/i·l. BOB i/i2), and SSS 1/il are examined as seed materials. The addition of all powders accelerated the crystallization of dark chocolate. Fat bloom stability is also improved by the seed crystals, except w ith SSS. The effect is highly dependent on the physical properties of the seed material employed. The most influencing factors are the similarities in the polymorphic behavior between the seed material and cocoa butter, especially, chain length structure. Thermal stability of the seed crystal is also very important. In view of all physical properties examined, the present review concludes that the p2 form of BOB performs best as a seed material. In particular, it gives rise to an accelerated crystallization of form V of CB and moderates change in viscosity and antibloom effects after thermal incubation of dark chocolate below and above the melting point of CB
Drug resistance in non-B subtype HIV-1: Impact of HIV-1 reverse transcriptase inhibitors
Human immunodeficiency virus (HIV) causes approximately 2.5 million new infections every year, and nearly 1.6 million patients succumb to HIV each year. Several factors, including cross-species transmission and error-prone replication have resulted in extraordinary genetic diversity of HIV groups. One of these groups, known as group M (main) contains nine subtypes (A-D, F-H and J-K) and causes ∼95% of all HIV infections. Most reported data on susceptibility and resistance to anti-HIV therapies are from subtype B HIV infections, which are prevalent in developed countries but account for only ∼12% of all global HIV infections, whereas non-B subtype HIV infections that account for ∼88% of all HIV infections are prevalent primarily in low and middle-income countries. Although the treatments for subtype B infections are generally effective against non-B subtype infections, there are differences in response to therapies. Here, we review how polymorphisms, transmission efficiency of drug-resistant strains, and differences in genetic barrier for drug resistance can differentially alter the response to reverse transcriptase-targeting therapies in various subtypes
Study of electron anti-neutrinos associated with gamma-ray bursts using KamLAND
We search for electron anti-neutrinos () from long and
short-duration gamma-ray bursts~(GRBs) using data taken by the KamLAND detector
from August 2002 to June 2013. No statistically significant excess over the
background level is found. We place the tightest upper limits on
fluence from GRBs below 7 MeV and place first constraints on
the relation between luminosity and effective temperature.Comment: 16 pages and 5 figure
On the Steady Nature of Line-Driven Disk Winds: Application to Cataclysmic Variables
We apply the semi-analytical analysis of the steady nature of line-driven
winds presented in two earlier papers to disk winds driven by the flux
distribution of a standard Shakura & Sunyaev (1973) disk for typical
cataclysmic variable (CV) parameters. We find that the wind critical point
tends to be closer to the disk surface towards the inner disk regions. Our main
conclusion, however, is that a line-driven wind, arising from a steady disk
flux distribution of a standard Shakura-Sunyaev disk capable of locally
supplying the corresponding mass flow, is steady. These results confirm the
findings of an earlier paper that studied "simple" flux distributions that are
more readily analyzable than those presented here. These results are consistent
with the steady velocity nature of outflows observationally inferred for both
CVs and quasi-stellar objects (QSOs). We find good agreement with the 2.5D CV
disk wind models of Pereyra and collaborators. These results suggest that the
likely scenario to account for the wind outflows commonly observed in CVs is
the line-driven accretion disk wind scenario, as suggested early-on by Cordova
& Mason (1982). For QSOs, these results show that the line-driven accretion
disk wind continues to be a promising scenario to account for the outflows
detected in broad absorption line (BAL) QSOs, as suggested early-on by Turnshek
(1984), and analyzed in detail by Murray et al. (1995).Comment: 35 pages, 20 figure
KamLAND Sensitivity to Neutrinos from Pre-Supernova Stars
In the late stages of nuclear burning for massive stars (M>8~M_{\sun}), the
production of neutrino-antineutrino pairs through various processes becomes the
dominant stellar cooling mechanism. As the star evolves, the energy of these
neutrinos increases and in the days preceding the supernova a significant
fraction of emitted electron anti-neutrinos exceeds the energy threshold for
inverse beta decay on free hydrogen. This is the golden channel for liquid
scintillator detectors because the coincidence signature allows for significant
reductions in background signals. We find that the kiloton-scale liquid
scintillator detector KamLAND can detect these pre-supernova neutrinos from a
star with a mass of 25~M_{\sun} at a distance less than 690~pc with 3
significance before the supernova. This limit is dependent on the neutrino mass
ordering and background levels. KamLAND takes data continuously and can provide
a supernova alert to the community.Comment: 19 pages, 6 figures, 1 tabl
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