Ekaterina Karpova

Ekaterina Karpova


Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 October 2021 in Construction and Building Materials
Verified
Journal Article
Closed access
EKEkaterina Karpova
Ekaterina Karpova
Gintautas SkripkiunasGintautas Skripkiunas
Gintautas Skripkiunas
IBIrmantas Barauskas
Irmantas Barauskas
IBIeva Barauskienė
Ieva Barauskienė
Jakub HodulJakub Hodul
Jakub Hodul

1 January 2018 in Advances in Materials Science and Engineering
Verified
Journal Article
Open access
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GSGintautas Skripkiunas
Gintautas Skripkiunas
EKEkaterina Karpova
Ekaterina Karpova
IBIrmantas Barauskas
Irmantas Barauskas
JBJoana Bendoraitiene
Joana Bendoraitiene
GYGrigory Yakovlev
Grigory Yakovlev
The evaluation of rheological properties of cement systems is getting more relevant with growing interest to self‐consolidating concrete (SCC), high‐performance concrete (HPC) and ultrahigh‐performance concrete (UHPC). The rheology models are a perspective tool to predict and manage the properties of cement systems in the fresh and hardened state. The current research is focused on the rheological test of cement systems modified by multiwalled carbon nanotubes (MWCNT) dispersion with and without polycarboxylate ether (PCE). The content of dispersion with 1% concentration of MWCNT in cement pastes varied from 0.125 to 0.5% by weight of cement. The dosage of PCE was taken as 0.6% by weight of cement. The cement pastes were prepared based on Portland cement without mineral additives. The rheological test was carried out at 5, 30, 60, and 120 min after mixing of cement paste. The rheological test established that modification of cement pastes by MWCNT dispersion in dosage 0.25% leads to the decrease of yield stress by 30.7% and increase of plastic viscosity by 29.6%. The combined modification by PCE and MWCNT dispersion shows the decrease in plastic viscosity of cement pastes by 9.90% in dosage of MWCNT equal to 0.5% by weight of cement, reduction of water demand by 20% for the same workability, and decrease of yield stress till 0 Pa. It gives the ability to obtain the self‐compacting mixtures. The cement pastes with and without MWCNT dispersion revealed the shear‐thinning behavior during 120 min after mixing. The modification of cement pastes by PCE with and without MWCNT dispersion showed the shear‐thickening behavior which remains during 120 min after mixing.

10 January 2025 in Advanced Materials
Verified
Journal Article
Open access
CPCamilla Pegoraro
Camilla Pegoraro
EKEkaterina Karpova
Ekaterina Karpova
YQYusuf Qutbuddin
Yusuf Qutbuddin
ESEsther Masiá Sanchis
Esther Masiá Sanchis
PDPavels Dimitrijevs
Pavels Dimitrijevs
MVMaria Vicent
Maria Vicent
Mitochondria play critical roles in regulating cell fate, with dysfunction correlating with the development of multiple diseases, emphasizing the need for engineered nanomedicines that cross biological barriers. Said nanomedicines often target fluctuating mitochondrial properties and/or present inefficient/insufficient cytosolic delivery (resulting in poor overall activity), while many require complex synthetic procedures involving targeting residues (hindering clinical translation). The synthesis/characterization of polypeptide‐based cell penetrating diblock copolymers of poly‐L‐ornithine (PLO) and polyproline (PLP) (PLOn‐PLPm, n:m ratio 1:3) are described as mitochondria‐targeting nanocarriers. Synthesis involves a simple two‐step methodology based on N‐carboxyanhydride ring‐opening polymerization, with the scale‐up optimization using a “design of experiments” approach. The molecular mechanisms behind targetability and therapeutic activity are investigated through physical/biological processes for diblock copolymers themselves or as targeting moieties in a poly‐L‐glutamic (PGA)‐based conjugate. Diblock copolymers prompt rapid cell entry via energy‐independent mechanisms and recognize mitochondria through the mitochondria‐specific phospholipid cardiolipin (CL). Stimuli‐driven conditions and mitochondria polarization dynamics, which decrease efficacy depending on disease type/stage, do not compromise diblock copolymer uptake/targetability. Diblock copolymers exhibit inherent concentration‐dependent anti‐tumorigenic activity at the mitochondrial level. The diblock copolymer conjugate possesses improved safety, significant cell penetration, and mitochondrial accumulation via cardiolipin recognition. These findings may support the development of efficient and safe mitochondrial‐targeting nanomedicines.

29 September 2020 in Fluids
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Journal Article
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Gintautas SkripkiunasGintautas Skripkiunas
Gintautas Skripkiunas
EKEkaterina Karpova
Ekaterina Karpova
JBJoana Bendoraitienė
Joana Bendoraitienė
IBIrmantas Barauskas
Irmantas Barauskas
In this study, the rheological properties of cement paste modified by a suspension containing both multi-walled carbon nanotubes (MWCNT) and carboxymethyl cellulose (CMC) (MWCNT/CMC suspension) with different types of plasticising admixtures (Pl), such as lignosulphonate (LS), sulfonated naphthalene formaldehyde condensate (NF), and polycarboxylate ether (PCE) were evaluated. The increase in yield stress and plastic viscosity up to 20% was established in the case of the modification of cement-based mixtures by MWCNT in the dosage up to 0.24% by weight of cement (bwoc) without Pl and with LS and NF. The complex modification of cement paste by MWCNT and PCE increases the yield stress and plastic viscosity from the MWCNT dosage of 0.06% and 0.015% bwoc, respectively. The yield stress and plastic viscosity of cement paste with PCE enhanced by 265% and 107%, respectively, in a MWCNT dosage of 0.12% bwoc. MWCNT do not have a significant influence on the flow behaviour index of cement paste; however, in the case of usage of PCE, the shear thickening effect decreased from a MWCNT dosage of 0.03% bwoc. The significant reduction in the volume coefficient of water bleeding by 99, 100, and 83% was obtained with LS, NF, and PCE, respectively, with an increase in MWCNT dosage up to 0.24% bwoc.

1 November 2019 in IOP Conference Series: Materials Science and Engineering
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Conference Paper
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GSG Skripkiunas
G Skripkiunas
EKEkaterina Karpova
Ekaterina Karpova
JBJ Bendoraitiene
J Bendoraitiene
IBI Barauskas
I Barauskas
Polycarboxylate ether (PCE) plasticizer possesses by high water-reduction capability of about 30-40%. Despite the superior water reduction capability, the high dosages of PCE may cause the bleeding in cement systems, which is not suitable for high workability and self-compacting concrete. The current research is devoted to the studying of multi-walled carbon nanotubes (MWCNT) suspension prepared in combination with PCE plasticizer on the rheological properties of cement pastes. The bleeding of cement pastes modified by different dosages of MWCNT was estimated as well. The increase of yield stress in 3.7 and 3.5 times was obtained for cement paste modified by MWCNT suspension in dosage of 0.12% by weight of cement (bwoc) in 5 and 120 min after cement paste mixing, respectively. The increase of plastic viscosity in 2.95 and 1.55 times was obtained for cement paste modified by MWCNT suspension in dosage of 0.12% bwoc in 5 and 120 min after cement paste mixing, respectively. Modification of cement pastes by MWCNT suspension in the dosage of 0.24 % bwoc led to the decrease of bleeding water volume by 21.7% in comparison with cement pastes modified only by PCE plasticizer.

14 December 2018 in MATEC Web of Conferences
Verified
Journal Article
Open access
Gintautas SkripkiunasGintautas Skripkiunas
Gintautas Skripkiunas
Grigory YakovlevGrigory Yakovlev
Grigory Yakovlev
EKEkaterina Karpova
Ekaterina Karpova
The current research is devoted to the studying of multi-walled carbon nanotubes (MWCNT) dispersion and its influence on the rheological properties of cement pastes. The pH and electrical conductivity test, zeta potential measurements, particle size analysis were performed for characterization of MWCNT dispersion. The MWCNT dispersion were tested during 1 month and presented the decrease of pH level from 8.89 to 8.02, increase of electrical conductivity from 2.00 to 2.75 mS/cm. The particle size analysis did not reveal the significant changes during 1 month of storage. The rheological test of nanomodified cement pastes were performed for concentration of MWCNT dispersion in the range from 0 to 0.5% by weight of cement. The decrease of yield stress by 30.7% and increase of plastic viscosity by 29.6% were obtained for cement paste modified by MWCNT dispersion in dosage of 0.25% by weight of cement. The changes in flow behaviour were established for cement pastes tested in 5 min after mixing and were not observed for cement pastes tested after 120 min of mixing.