4,246 research outputs found
Optical tweezer for probing erythrocyte membrane deformability
We report that the average rotation speed of optically trapped crenated
erythrocytes is direct signature of their membrane deformability. When placed
in hypertonic buffer, discocytic erythrocytes are subjected to crenation. The
deformation of cells brings in chirality and asymmetry in shape that make them
rotate under the scattering force of a linearly polarized optical trap. A
change in the deformability of the erythrocytes, due to any internal or
environmental factor, affects the rotation speed of the trapped crenated cells.
Here we show how the increment in erythrocyte membrane rigidity with adsorption
of ions can be exhibited through this approach.Comment: Published in Appl. Phys. Lett. 95, 233703 (2009); Two supplementary
multimedia files are available at the journal page:
http://link.aip.org/mm/APPLAB/1.3272269/083949aplv1.mov and
http://link.aip.org/mm/APPLAB/1.3272269/083949aplv2.mo
Calculation of the neutron electric dipole moment with two dynamical flavors of domain wall fermions
We present a study of the neutron electric dipole moment () within
the framework of lattice QCD with two flavors of dynamical lig ht quarks. The
dipole moment is sensitive to the topological structure of the gaug e fields,
and accuracy can only be achieved by using dynamical, or sea quark, calc
ulations. However, the topological charge evolves slowly in these calculations,
le ading to a relatively large uncertainty in . It is shown, using
quenched configurations, that a better sampling of the charge d istribution
reduces this problem, but because the CP even part of the fermion determinant
is absent, both the topological charge dis tribution and are
pathological in the chiral limit. We discuss the statistical and systematic
uncertainties arising from the topological charge distr ibution and unphysical
size of the quark mass in our calculations and prospects fo r eliminating them.
Our calculations employ the RBC collaboration two flavor domain wall fermion
and DBW2 gauge action lattices with inverse lattice spacing 1.7
GeV, physical volume fm), and light quark mass roughly equal
to the strange quark mass ( and 0.04). We determine a value of
the electric dipole moment that is zero withi n (statistical) errors, e--fm at the smaller sea quark mass. Satisfactory
results for the magnetic and electric form factors of the proton and neutron
are also obtained and presented.Comment: 46 pages. Changed one author addres
Trapping and sorting active particles: motility-induced condensation & smectic defects
We present an experimental realization of the collective trapping phase
transition [Kaiser et al., PRL 108, 268307 (2012)], using motile polar granular
rods in the presence of a V-shaped obstacle. We offer a theory of this
transition based on the interplay of motility-induced condensation and
liquid-crystalline ordering and show that trapping occurs when persistent
influx overcomes the collective expulsion of smectic defect structures. In
agreement with the theory, our experiments find that a trap fills to the brim
when the trap angle is below a threshold , while all
particles escape for . Our simulations support a further
prediction, that goes down with increasing rotational noise. We
exploit the sensitivity of trapping to the persistence of directed motion to
sort particles based on the statistical properties of their activityComment: 6 pages, 5 figures, for supplementary mpg files, see
"https://www.dropbox.com/sh/3cmswfoysdn0sb6/AACpEp-G3768B6Y62nDFj_Hea?dl=0".
This paper supersedes our earlier version arXiv:1603.08535 and contains
substantial new results including revised theoretical treatmen
Scalar meson in dynamical and partially quenched two-flavor QCD: lattice results and chiral loops
This is an exploratory study of the lightest non-singlet scalar
state on the lattice with two dynamical quarks. Domain Wall fermions are used
for both sea and valence quarks on a 16^3*32 lattice with an inverse lattice
spacing of 1.7 GeV. We extract the scalar meson mass 1.58(34) GeV from the
exponential time-dependence of the dynamical correlators with
and N_f=2. Since this statistical error-bar from dynamical correlators is
rather large, we analyze also the partially quenched lattice correlators with
not equal . They are positive for and
negative for . In order to understand this striking effect of
partial quenching, we derive the scalar correlator within the Partially
Quenched ChPT and find it describes lattice correlators well. The leading
unphysical contribution in Partially Quenched ChPT comes from the exchange of
the two pseudoscalar fields and is also positive for and
negative for at large t. After the subtraction of this
unphysical contribution from the partially quenched lattice correlators, the
correlators are positive and exponentially falling. The resulting scalar meson
mass 1.51(19) GeV from the partially quenched correlators is consistent with
the dynamical result and has appreciably smaller error-bar.Comment: 23 pages, 8 figure
The contribution of transcriptomic and proteomic analysis in elucidating stress adaptation responses of Listeria monocytogenes
The foodborne transmission of Listeria monocytogenes requires physiological adaptation to various conditions, including the cold, osmotic, heat, acid, alkaline, and oxidative stresses, associated with food hygiene, processing, and preservation measures. We review the current knowledge on the molecular stress adaptation responses in L. monocytogenes cells as revealed through transcriptome, proteome, genetic, and physiological analysis. The adaptation of L. monocytogenes to stress exposure is achieved through global expression changes in a large number of cellular components. In addition, the cross-protection of L. monocytogenes exposed to different stress environments might be conferred through various cellular machineries that seem to be commonly activated by the different stresses. To assist in designing L. monocytogenes mitigation strategies for ready-to-eat food products, further experiments are warranted to specifically evaluate the effects of food composition, additives, preservatives, and processing technologies on the modulation of L. monocytogenes cellular components in response to specific stresses
Effective and Efficient Algorithms for Concise Range Queries
With the advance of wireless communication technology, it is quite common for people to view maps or get related services from the handheld devices, such as mobile phones and PDAs. Range queries, as one of the most commonly used tools, are often posed by the users to retrieve needful information from a spatial database. However, due to the limits of communication bandwidth and hardware power of handheld devices, displaying all the results of a range query on a handheld device is neither communication efficient nor informative to the users. This is simply because that there are often too many results returned from a range query. In view of this problem, we present a novel idea that a concise representation of a specified size for the range query results, while incurring minimal information loss, shall be computed and returned to the user. Such a concise range query not only reduces communication costs, but also offers better usability to the users, providing an opportunity for interactive exploration. The usefulness of the concise range queries is confirmed by comparing it with other possible alternatives, such as sampling and clustering. Unfortunately, we prove that finding the optimal representation with minimum information loss is an NP-hard problem. Therefore, we propose several effective and nontrivial algorithms to find a good approximate result. Extensive experiments on real-world data have demonstrated the effectiveness and efficiency of the proposed techniques
Direct CP violation in neutral kaon decays
The final result is presented of the NA48 Experiment performed at CERN SPS
neutral kaon beams on the direct CP violation parameter Re(epsilon'/epsilon),
as maesured from the decay rates of neutral kaons into two pions. The data
collected in years 1997-2001 yield the evidence for direct CP violation with
Re(epsilon'/epsilon)=(14.7+-2.2)10^-4. Description of expermental method and
systematics, comparison with world data and some discussion of implications for
theory are given.Comment: 5 pp., 3 figs, presented on behalf of NA48 Collaboration at PASCOS
2003 Conference, Mumbai, India, 2-8 Jan 2003, to appear in Praman
Naphtha Reduction of Iron Ores to Sponge Iron in Continuous Vertical Reactor
The development of a process of sponge iron production by naphtha, a petroleum by-product, in a continuous 90mm I.D. vertical reactor is discussed. The process, the equipment and the operational parameters, the results of the campaigns with various iron ores pellets are described.
Sized iron ore fines from two deposits were directly reduced by petroleum naphtha to sponge iron at a temperature of about 1000 deg. C. maintaining naphtha injection at different controlled flow rates. The movement of solids in the reactor column was also controlled to obtain predetermined residence times.producing 70-100 kgs of sponge iron per day. Under optium conditions 98 percent metallization was obtained.
The results are discussed in the light of efficiency of the reductant and the economics of the process
SYNTHETIC AND ANTIMICROBIAL ACTIVITY OF 4 THIAZOLIDINONES
Objective: Thiazolidinone, a saturated form of thiazole with carbonyl group on the fourth carbon, has been considered as magic moieties (Wonder nucleus) which possess almost all types of biological activities. This diversity in the biological response profile has attracted the attention of many researchers to explore this skeleton to its multiple potential against several activities
Methods: Looking to the importance of N and S hetero cycles in the medical field, 4-thiazolidinone derivatives (3b,4b) have been synthesized by cyclization of substituted imines(1a,2a) with mercaptoacetic acid in presence of anhydrous ZnCl2 as a catalyst in DMF. The 4-thiazolidinone derivatives have also been tested against two bacterial strains viz. S. aureus and E. coli and two fungal pathogens viz. A. niger and C. albicans using Kirby-Bauer method.
Result: New series of azomethines and 4 thiazolidinones compounds have been prepared. The synthesized compounds were characterized on the basis of IR, 1H-NMR, and elemental analysis. The purity of the compounds was checked using pre coated TLC plates (MERCK) using n-hexane: ethyl acetate (8:2) solvent system. The synthesized compounds show good antimicrobial acivity.
Conclusion: The zone of inhibition is directly proportional to the degree of sensitivity of the bacterial, fungal strain and concentration of compound under test. A systematic perusal data of antimicrobial activity reveals that, with the increase in concentration of drug, increase in zone of inhibition occur in petridish. Better antimicrobial activity have been pointed out in synthesized compounds
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