231 research outputs found
Stability Studies of a Mixture of Paracetamol and Ascorbic Acid, Prepared Extempore, at Elevated Temperature and Humidity Conditions
Purpose: To determine the effect of the temperature of water used for the preparation of paracetamol and ascorbic acid mixture on its stability, as well as to assess the influence of humidity on the stability of single components and their mixtures.Methods: The stability of the mixtures in aqueous medium was evaluated with the aid of UVâVis spectrophotometer interfaced with a computer. Spectral analysis was adapted to monitor changes in the aqueous medium of a commercial paracetamol and ascorbic acid mixture, an extemporaneously prepared mixture of paracetamol and ascorbic acid, and the individual preparations of paracetamol and ascorbic acid.Results: The degradation rate was lower in commercial preparation (6.80 Ă 10-3 min-1), compared to that of the extemporaneously prepared ascorbic acid/paracetamol mixture (2.30 Ă 10-2 min-1). The decomposition of the commercial product in aqueous medium was 3.38 times slower than that of the extemporaneously prepared mixture. Ascorbic acid, tested under the same conditions as the commercial product, was unstable in aqueous solutions, with a degradation rate of 1.17Ă10-2 min-1. Ascorbic acid, dissolved in water, degraded completely within 4 h at room temperature, whereas paracetamol remained stable under the same conditions for 11 days.Conclusion: The individual drugs in their original form retained their stability for 72 h, but some of the mixtures, in particular, the extemporaneously prepared ones showed more rapid degradation. Extemporaneous preparation of paracetamol/ascorbic acid liquid mixtures should not be encouraged
Measurement of Decays and Search for
We report on a search for the decay and other charmless
modes with a final state, including
, non-resonant ,
, and . These results are obtained from a data sample containing
657 million pairs collected with the Belle detector at the KEKB
asymmetric-energy collider. We set an upper limit on
of at the 90% confidence
level (C.L.). From our measurement and an isospin
analysis, we determine the Cabibbo-Kobayashi-Maskawa phase to be degrees. We find excesses in and
non-resonant with 1.3 and 2.5 significance,
respectively. The corresponding branching fractions are less than and at the 90% C.L. In addition, we set 90% C.L.
upper limits as follows: , , and
.Comment: 6 pages, 2 figures. Submitted to PRD(RC
Measurement of the ratio B(D0->pi+pi-pi0)/B(D0->K-pi+pi0) and the time-integrated CP asymmetry in D0->pi+pi-pi0
We report a high-statistics measurement of the relative branching fraction
B(D0->pi+pi-pi0)/B(D0->K-pi+pi0) using a 532 fb^{-1} data sample collected with
the Belle detector at the KEKB asymmetric-energy e+e- collider. The measured
value of the relative branching fraction is B(D0->pi+pi-pi0)/B(D0->K-pi+pi0) =
(10.12 +/- 0.04(stat) +/- 0.18(syst))x10^{-2} which has an accuracy comparable
to the world average. We also present a measurement of the time-integrated CP
asymmetry in D0->pi+pi-pi0 decay. The result, A_{CP} = (0.43 +/- 1.30)%, shows
no significant CP violation.Comment: 15 pages, 11 figures, submitted to Physics Letters
A unique Valanginian paleoenvironment at an iron ore deposit near ZengĆvĂĄrkony (Mecsek Mts, South Hungary), and a possible genetic model
Abstract
The spatially restricted Early Valanginian iron ore (limonite) and manganese deposit at ZengĂ”vĂĄrkony (Mecsek Mts, southern Hungary) contains a rich, strongly limonitized, remarkably large-sized (specimens are 30â70% larger than those at their type localities) brachiopod-dominated (mainly Lacunosella and Nucleata) megafauna and a diverse crustacean microfauna, which indicates a shallow, nutrient-rich environment possibly linked to an uplifted block, and/or a hydrothermal vent
Measurement of charged particle multiplicities in collisions at TeV in the forward region
The charged particle production in proton-proton collisions is studied with
the LHCb detector at a centre-of-mass energy of TeV in different
intervals of pseudorapidity . The charged particles are reconstructed
close to the interaction region in the vertex detector, which provides high
reconstruction efficiency in the ranges and
. The data were taken with a minimum bias trigger, only requiring
one or more reconstructed tracks in the vertex detector. By selecting an event
sample with at least one track with a transverse momentum greater than 1 GeV/c
a hard QCD subsample is investigated. Several event generators are compared
with the data; none are able to describe fully the multiplicity distributions
or the charged particle density distribution as a function of . In
general, the models underestimate the charged particle production
Measurement of B meson production cross-sections in proton-proton collisions at âs= 7 TeV
The production cross-sections of B mesons are measured in pp collisions at a centre-of-mass energy of 7 TeV using data collected with the LHCb detector corresponding to a integrated luminosity of 0.36fbâ1. The B+, B0 and B0s mesons are reconstructed in the exclusive decays B+âJ/ÏK+, B0âJ/ÏKâ0 and B0sâJ/ÏÏ, with J/ÏâÎŒ+ÎŒâ, Kâ0âK+Ïâ and ÏâK+Kâ. The differential cross-sections are measured as functions of B meson transverse momentum pT and rapidity y, in the range 0 < pT<40GeV/c2 and 2.0<y<4.5. The integrated cross-sections in the same pT and y ranges, including charge-conjugate states, are measured to be
Ï(ppâB++X)=38.9±0.3(stat.)±2.5(syst.)±1.3(norm.)ÎŒb,
Ï(ppâB0+X)=38.1±0.6(stat.)±3.7(syst.)±4.7(norm.)ÎŒb,
Ï(ppâB0s+X)=10.5±0.2(stat.)±0.8(syst.)±1.0(norm.)ÎŒb,
where the third uncertainty arises from the pre-existing branching fraction measurements
Study of B0(s)âK0Sh+hâČâ decays with first observation of B0sâK0SK±Ïâ and B0sâK0SÏ+Ïâ
A search for charmless three-body decays of B 0 and B0s mesons with a K0S meson in the final state is performed using the pp collision data, corresponding to an integrated luminosity of 1.0 fbâ1, collected at a centre-of-mass energy of 7 TeV recorded by the LHCb experiment. Branching fractions of the B0(s)âK0Sh+hâČâ decay modes (h (âČ) = Ï, K), relative to the well measured B0âK0SÏ+Ïâ decay, are obtained. First observation of the decay modes B0sâK0SK±Ïâ and B0sâK0SÏ+Ïâ and confirmation of the decay B0âK0SK±Ïâ are reported. The following relative branching fraction measurements or limits are obtained B(B0âK0SK±Ïâ)B(B0âK0SÏ+Ïâ)=0.128±0.017(stat.)±0.009(syst.), B(B0âK0SK+Kâ)B(B0âK0SÏ+Ïâ)=0.385±0.031(stat.)±0.023(syst.), B(B0sâK0SÏ+Ïâ)B(B0âK0SÏ+Ïâ)=0.29±0.06(stat.)±0.03(syst.)±0.02(fs/fd), B(B0sâK0SK±Ïâ)B(B0âK0SÏ+Ïâ)=1.48±0.12(stat.)±0.08(syst.)±0.12(fs/fd)B(B0sâK0SK+Kâ)B(B0âK0SÏ+Ïâ)â[0.004;0.068]at90%CL
Searches for B0(s)âJ/ÏppË and B+âJ/ÏppËÏ+ decays
The results of searches for B0(s)âJ/Ï ppÂŻ and B + â J/Ï p pÂŻ Ï+ decays are reported. The analysis is based on a data sample, corresponding to an integrated luminosity of 1.0 fbâ1 of pp collisions, collected with the LHCb detector. An excess with 2.8 Ï significance is seen for the decay B0sâJ/Ï ppÂŻ and an upper limit on the branching fraction is set at the 90 % confidence level: B(B0sâJ/Ï ppÂŻ) < 4.8 Ă 10â6, which is the first such limit. No significant signals are seen for B0 â J/Ï ppÂŻ and B+ â J/Ï ppÂŻ Ï + decays, for which the corresponding limits are set: B(B0âJ/Ï ppÂŻ) < 5.2 Ă 10â7, which significantly improves the existing limit; and B(B+âJ/Ï ppÂŻÏ+) < 5.0 Ă 10â7, which is the first limit on this branching fraction
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) and the direct CP asymmetry in B0 -> K*0 gamma
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1
of pp collision data collected by the LHCb experiment at a centre-of-mass
energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 ->
phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the
first uncertainty is statistical, the second is the experimental systematic
uncertainty and the third is associated with the ratio of fragmentation
fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the
branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x
10^{-5}.
The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with
the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/-
0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the
previous experimental results and theoretical expectations.Comment: 21 pages, 3 figues, 4 table
Branching fraction and CP asymmetry of the decays B+âK0SÏ+ and B+âK0SK+
An analysis of B+ â K0
SÏ+ and B+ â K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fbâ1 and 2 fbâ1 collected at centre-ofmass
energies of
â
s = 7 TeV and
â
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ â K0
S K+
)/B(B+ â K0
SÏ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ â K0
SÏ+
) = â0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ â K0
S K+
) =
â0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
â
s = 7 TeV is used to search for
B+
c
â K0
S K+ decays and results in the upper limit ( fc · B(B+
c
â K0
S K+
))/( fu · B(B+ â K0
SÏ+
)) <
5.8 Ă 10â2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ÂŻb
quark
into a B+
c or a B+ meson, respectively
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