2,645 research outputs found
Representatiivsete proovide võtmine reostunud pinnase kuhjadest
Töö keskendub representatiivsete proovide võtmisele reostunud pinnase kuhjadest. Töö esimeses pooles antakse ülevaade proovivõtu teoreetilistest alustest. Käsitletakse pinnase partii mõõtmelisust ja heterogeensust ning kirjeldatakse proovivõtul tekkivaid võimalikke proovivõtu vigu. Samuti kirjeldatakse erinevaid viise, mida saab kasutada proovi massi vähendamiseks.
Töö raames viidi läbi patendi teemauuring, et saada ülevaadet leiutistest, mida saaks rakendada proovide võtmisel saastunud pinnase kuhjadest. Uuringuga leiti viis sellekohast leiutist ning nende rakendatavust on töös võrreldud.
Töö raames viidi läbi ka akrediteeringu-uuring, et tuvastada, millised Eestis tegutsevad asutused ja ettevõtted omavad akrediteeringut pinnaseproovide võtmiseks ja analüüsimiseks. Leiti kolm ettevõtet akrediteeringuga naftasaaduste sisalduse määramiseks pinnases ja neist ühel on ka akrediteering pinnaseproovide võtmiseks, kuid akrediteeritud meetod ei hõlma proovivõttu pinnasekuhjadest.
Proovivõtu teoorias toodud praktilisi võtteid katsetati võrdleval proovivõtmisel saastunud pinnase töötlemise väljakul ja jääkreostuse likvideerimistöö objektil. Proove võeti kokku neljast pinnasekuhjast erinevatel meetoditel ning proovi massi vähendamiseks kasutati samuti erinevaid võtteid. Saadud proovides määrati akrediteeritud laborites naftasaaduste sisaldused ning saadud tulemusi on analüüsitud ning nende põhjal on antud hinnanguid kasutatud proovivõtu meetodite kohta. Töös on antud ka praktilised soovitused representatiivseks proovivõtuks pinnasekuhjadest.
Töö eesmärk kirjeldada representatiivse proovivõtu metoodika reostunud pinnase kuhjadest proovide võtmiseks on täidetud. Kuna katsetulemused ei kinnitanud esimese auna puhul olulist erinevust representatiivse ja vähem representatiivse proovivõtu metoodika vahel, siis on antud töö baasil võimalik edasi uurida proovivõtu vigade ilmnemist suurema arvu proovivõtu puhul. Samuti on võimalik katseliselt kindlaks teha, kui kaua püsivad läbisegatud aunas 0D partii omadused ehk millise aja möödudes ei anna auna pinnalt proovide võtmine enam usaldusväärseid tulemusi
Adenovirus adenine nucleotide translocator-2 shRNA effectively induces apoptosis and enhances chemosensitivity by the down-regulation of ABCG2 in breast cancer stem-like cells
Cancer stem cells (CSCs) are resistant to chemo- and radio-therapy, and can survive to regenerate new tumors. This is an important reason why various anti-cancer therapies often fail to completely control tumors, although they kill and eliminate the bulk of cancer cells. In this study, we determined whether or not adenine nucleotide translocator-2 (ANT2) suppression could also be effective in inducing cell death of breast cancer stem-like cells. A sub-population (SP; CD44+/CD24-) of breast cancer cells has been reported to have stem/progenitor cell properties. We utilized the adeno-ANT2 shRNA virus to inhibit ANT2 expression and then observed the treatment effect in a SP of breast cancer cell line. In this study, MCF7, MDA-MB-231 cells, and breast epithelial cells (MCF10A) mesenchymally-transdifferentiated through E-cadherin knockdown were used. ANT2 expression was high in both stem-like cells and non-stem-like cells of MCF7 and MDA-MB-231 cells, and was induced and up-regulated by mesenchymal transdifferentiation in MCF10A cells (MCF10AEMT). Knockdown of ANT2 by adeno-shRNA virus efficiently induced apoptotic cell death in the stem-like cells of MCF7 and MDA-MB-231 cells, and MCF10AEMT. Stem-like cells of MCF7 and MDA-MB-231, and MCF10AEMT cells exhibited increased drug (doxorubicin) resistance, and expressed a multi-drug resistant related molecule, ABCG2, at a high level. Adeno-ANT2 shRNA virus markedly sensitized the stem-like cells of MCF7 and MDA-MB-231, and the MCF10AEMT cells to doxorubicin, which was accompanied by down-regulation of ABCG2. Our results suggest that ANT2 suppression by adeno-shRNA virus is an effective strategy to induce cell death and increase the chemosensitivity of stem-like cells in breast cancer
Precision Measurement of the Mass of the Lepton
An energy scan near the pair production threshold has been performed
using the BESIII detector. About pb of data, distributed over four
scan points, was collected. This analysis is based on pair decays to
, , , , , , , and
final states, where denotes a charged or . The mass of the
lepton is measured from a maximum likelihood fit to the pair production
cross section data to be )
MeV/, which is currently the most precise value in a single measurement.Comment: 13 pages, 7 figure
Search for the radiative transitions and
By using a 2.92 fb data sample taken at GeV with
the BESIII detector operating at the BEPCII collider, we search for the
radiative transitions and
through the hadronic decays . No
significant excess of signal events above background is observed. We set upper
limits at a 90% confidence level for the product branching fractions to be
and
. Combining our result with world-average
values of , we find the
branching fractions
and at a 90%
confidence level.Comment: 10 pages, 4 figure
Measurements of the observed cross sections for exclusive light hadron production in e^+e^- annihilation at \sqrt{s}= 3.773 and 3.650 GeV
By analyzing the data sets of 17.3 pb taken at GeV
and 6.5 pb taken at GeV with the BESII detector at the
BEPC collider, we have measured the observed cross sections for 12 exclusive
light hadron final states produced in annihilation at the two energy
points. We have also set the upper limits on the observed cross sections and
the branching fractions for decay to these final states at 90%
C.L.Comment: 8 pages, 5 figur
Observation of at BESIII
Using events collected with the BESIII detector
at the BEPCII storage rings, we observe for the first time the process
,
with a significance of ( including systematic
uncertainties). The product branching fraction of is measured to be
, where the first error is statistical and the
second is systematic. This measurement provides information on the
production near threshold coupling to and improves the understanding
of the dynamics of decays to four body processes.Comment: 8 pages, 7 figure
Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-
We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi -->
D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7
J/Psi events collected with the BESII detector at the BEPC. No excess of signal
above background is observed, and 90% confidence level upper limits on the
branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi
--> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure
Measurement of azimuthal asymmetries in inclusive charged dipion production in annihilations at = 3.65 GeV
We present a measurement of the azimuthal asymmetries of two charged pions in
the inclusive process based on a data set of 62
at the center-of-mass energy GeV collected with
the BESIII detector. These asymmetries can be attributed to the Collins
fragmentation function. We observe a nonzero asymmetry, which increases with
increasing pion momentum. As our energy scale is close to that of the existing
semi-inclusive deep inelastic scattering experimental data, the measured
asymmetries are important inputs for the global analysis of extracting the
quark transversity distribution inside the nucleon and are valuable to explore
the energy evolution of the spin-dependent fragmentation function.Comment: 7 pages, 5 figure
Measurement of the Cross Section between 600 and 900 MeV Using Initial State Radiation
We extract the cross section in the energy
range between 600 and 900 MeV, exploiting the method of initial state
radiation. A data set with an integrated luminosity of 2.93 fb taken at
a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII
collider is used. The cross section is measured with a systematic uncertainty
of 0.9%. We extract the pion form factor as well as the
contribution of the measured cross section to the leading order hadronic vacuum
polarization contribution to . We find this value to be
.Comment: 14 pages, 7 figures, accepted by PL
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