The paper is a contribution to the technical discussion concerning the collapses of the WTC buildings. It returns to the problem of the dynamics of the collapses;it does not concern the reason why the buildings starte...The paper is a contribution to the technical discussion concerning the collapses of the WTC buildings. It returns to the problem of the dynamics of the collapses;it does not concern the reason why the buildings started collapsing, but investigates the dynamics of the collapse itself. It works with the same assumptions as the official NIST report [1], i.e. that the falling mass hits the motionless mass beneath;the supporting columns loose stability and the mass of the pertinent floor starts to fall together with the falling mass. The aim was to derive the theoretical upper limit of the speed of the collapse, supposing that influence of the columns which resist the fall, is neglected. The differential equation of the fall was obtained using two independent laws of mechanics, with the identical result. Its solution can be found from a very simple explicit formula. The theoretical upper limit acceleration of the fall obtained by such formula is one third of the gravitational acceleration, which is faster than it was observed in the case of the collapses of WTC1 and WTC2. This leads to the conclusion that the mechanism of the collapse must be different from the assumed and the falling mass must not hit the motionless mass bellow it, but rather a mass which had started to fall before the impact of the falling mass occurred.展开更多
Platinum-based agents unwaveringly hold their prominent position in cancer treatment.Current research emphasizes finding novel complexes for hard-to-treat cancers with minimum side effects,capable of overcoming resist...Platinum-based agents unwaveringly hold their prominent position in cancer treatment.Current research emphasizes finding novel complexes for hard-to-treat cancers with minimum side effects,capable of overcoming resistance.This work presents easy-to-prepare diiodidoplatinum(II)complexes cis-[PtI_(2)(Ln)_(2)](1-7)with imidazole derivatives(Ln),which were considerably effective against multiple myeloma cell lines U266B1 and KMS12-PE.The leading compound 6(at 3μM concentration)extraordinarily reduced viability of U266B1 and KMS12-PE myeloma cells to 3.0%and 1.1%,respectively,and exceeded the conventional platinum-based anticancer drug cisplatin(93.1%and 88.3%,respectively)that is used clinically for the combination therapy of multiple myeloma.Complex 6 was significantly more effective in inducing apoptosis in KMS12-PE cells without interleukin-6(IL-6)expression than in U266B1 cells with IL-6 expression.Complex 6 also induced apoptosis in co-culture of KMS12-PE with non-cancerous stromal fibroblasts(HS-5),and displayed markedly lower activity in the HS-5 stromal fibroblast cells than in myeloma cells,pointing out its pharmocologically prospective selectivity towards the cancer cells over the normal ones.No caspase 3/7 activity was detected in apoptotic KMS12-PE cells treated by complex 6 indicating a different mechanism of apoptosis action from cisplatin.This work demonstrates that simple non-classical platinum(II)complexes represent a new perspective for a monotherapy of hard-to-treat multiple myeloma.展开更多
Two novel hexacoordinated Co(II)-based single-ion magnets were prepared and characterised.Both neutral complexes feature metal-centred coordination with one terminal and one bidentate nitrate anions along with trident...Two novel hexacoordinated Co(II)-based single-ion magnets were prepared and characterised.Both neutral complexes feature metal-centred coordination with one terminal and one bidentate nitrate anions along with tridentate derivatives of a 2,6-bis(1H-benzimidazole-2-yl)pyridine ligand containing either n-octyl(complex 1)or n-dodecyl(complex 2)chains.The presence of long aliphatic chains ensures their solubility in low polarity and volatile solvents frequently used for lithography patterning.This enabled the preparation of microstructural layers and patterns on technologically relevant substrates by easy-tohandle and low-cost wet lithographic techniques.On the other hand,attempts at surface deposition via sublimation were not successful due to thermal instability.展开更多
Three variants of 2-(pyridine-2-yl)-1H-benzimidazole bidentate ligands,with distinct pentyl substituents(n-pentyl(L1),(2S)-2-methylbutyl(L2S),and(2R)-2-methylbutyl(L2R)),were synthesized and employed to prepare magnet...Three variants of 2-(pyridine-2-yl)-1H-benzimidazole bidentate ligands,with distinct pentyl substituents(n-pentyl(L1),(2S)-2-methylbutyl(L2S),and(2R)-2-methylbutyl(L2R)),were synthesized and employed to prepare magnetically bistable cobalt_((II))and iron_((II))complexes.The cobalt_((II))complexes[Co(L1)(κ^(2)-NO_(3))_(2)(CH_(3)CN)](1),[Co(L2S)(κ^(2)-NO_(3))2(H_(2)O)](2S),[Co(L2R)(κ^(2)-NO_(3))2(H_(2)O)](2R)and[Co(L2)(κ^(2)-NO_(3))2(H_(2)O)](2rac)exhibit field supported slow relaxation of magnetisation,while the iron_((II))complexes[Fe(L2S)_(3)](CF_(3)SO_(3))_(2)·H_(2)O·CH_(3)NO_(2)·C_(5)H_(12)O(3S)and[Fe(L2S)_(3)]·1.5H_(2)O(3R)exhibit thermal spin crossover allocated above room temperature.Structural analysis revealed that the heptacoordinated cobalt_((II))complexes adopt a distorted pentagonal bipyramidal geometry,whereas the iron_((II))compounds contain hexacoordinated complex cations.Coordination compounds incorporating the chiral ligands L2S and L2R are optically active,with their enantiomeric relationship confirmed by circular dichroism spectroscopy.Computational studies provided insights into electron density distributions and bonding energetics(DFT and QT-AIM),predicted zero-field splitting parameters(CASSCF/NEVPT2),and quantified energies of the d-orbital,ligand field terms and their multiplets(via AILFT).Magnetic investigations of the cobalt_((II))complexes yielded experimental ZFS parameters and revealed distinct magnetization relaxation mechanisms:1 exhibits relaxation governed by a phonon bottle-neck process,whereas 2S and 2R involve a combination of Raman and direct relaxation processes.Notably,compounds 2S and 2R,despite being enantiomers and isostructural,exhibited distinct relaxation dynamics,attributable to differential phonon coupling pathways modulated by the chiral substituents.This is the first report demonstrating enantiomer-dependent slow relaxation of magnetisation behaviour in cobalt_((II))-based SMMs.These findings underscore the critical role of stereochemistry in modulating spin dynamics and magnetic bistability,providing design principles for future chiral magnetic materials.展开更多
This article presents a series of six mononuclear Co(II)complexes 1-6 featuring ligands derived from a hexadentate Schiff base family,originating from the condensation of(2-formylphenoxy)acetic acid with various diami...This article presents a series of six mononuclear Co(II)complexes 1-6 featuring ligands derived from a hexadentate Schiff base family,originating from the condensation of(2-formylphenoxy)acetic acid with various diamines.Notably,these complexes uniquely prefer a trigonal prism geometry,presenting a novel approach to synthesizing complexes with this distinctive shape.The compounds were characterized by elemental analysis,FT-IR spectroscopy,and single-crystal and powder XRD techniques.Furthermore,the magnetism was investigated by DC and AC magnetic measurements and also complemented by X-band EPR spectroscopy.The results reveal that the prepared complexes behave as field-induced single-molecule magnets,characterized by a substantial negative axial zero-field splitting D-parameter and spin reversal energetic barrier U_(eff) reaching values up to 72 K.The theoretical methods based on CASSCF/NEVPT2 calculations were applied to rationalize their magnetic properties.Moreover,these complexes hold promising potential for further functionalization,offering opportunities to enhance their properties,particularly towards developing zero-field single-molecule magnets as evidenced by the slow relaxation of magnetization in zero static magnetic field observed for the zinc-diluted complex 1Zn.展开更多
基金supported from the project of Ministry of Educa-tion,Youth and Sports of the Czech Republic AdMaS UP(Advanced Materials,Structures and Technologies),National Sustainability Programme I,LO1408.
文摘The paper is a contribution to the technical discussion concerning the collapses of the WTC buildings. It returns to the problem of the dynamics of the collapses;it does not concern the reason why the buildings started collapsing, but investigates the dynamics of the collapse itself. It works with the same assumptions as the official NIST report [1], i.e. that the falling mass hits the motionless mass beneath;the supporting columns loose stability and the mass of the pertinent floor starts to fall together with the falling mass. The aim was to derive the theoretical upper limit of the speed of the collapse, supposing that influence of the columns which resist the fall, is neglected. The differential equation of the fall was obtained using two independent laws of mechanics, with the identical result. Its solution can be found from a very simple explicit formula. The theoretical upper limit acceleration of the fall obtained by such formula is one third of the gravitational acceleration, which is faster than it was observed in the case of the collapses of WTC1 and WTC2. This leads to the conclusion that the mechanism of the collapse must be different from the assumed and the falling mass must not hit the motionless mass bellow it, but rather a mass which had started to fall before the impact of the falling mass occurred.
基金supported by PalackýUniversity Olomouc(projects PrF_2021_009,PrF_2022_006 and LF_2022_005)the European Regional Development Fund–Project ENOCH(No.CZ.02.1.01/0.0/0.0/16_019/0000868)+3 种基金the Ministry of Education,Youth and Sports of the Czech Republic under the project CEITEC 2020(LQ1601)Jagiellonian University Medical College(N42/DBS/000101)supported by the Slovak Research and Development Agency(APVV-19-0087)by the Scientific Grant Agency of the Slovak Republic(Project 1/0686/23).
文摘Platinum-based agents unwaveringly hold their prominent position in cancer treatment.Current research emphasizes finding novel complexes for hard-to-treat cancers with minimum side effects,capable of overcoming resistance.This work presents easy-to-prepare diiodidoplatinum(II)complexes cis-[PtI_(2)(Ln)_(2)](1-7)with imidazole derivatives(Ln),which were considerably effective against multiple myeloma cell lines U266B1 and KMS12-PE.The leading compound 6(at 3μM concentration)extraordinarily reduced viability of U266B1 and KMS12-PE myeloma cells to 3.0%and 1.1%,respectively,and exceeded the conventional platinum-based anticancer drug cisplatin(93.1%and 88.3%,respectively)that is used clinically for the combination therapy of multiple myeloma.Complex 6 was significantly more effective in inducing apoptosis in KMS12-PE cells without interleukin-6(IL-6)expression than in U266B1 cells with IL-6 expression.Complex 6 also induced apoptosis in co-culture of KMS12-PE with non-cancerous stromal fibroblasts(HS-5),and displayed markedly lower activity in the HS-5 stromal fibroblast cells than in myeloma cells,pointing out its pharmocologically prospective selectivity towards the cancer cells over the normal ones.No caspase 3/7 activity was detected in apoptotic KMS12-PE cells treated by complex 6 indicating a different mechanism of apoptosis action from cisplatin.This work demonstrates that simple non-classical platinum(II)complexes represent a new perspective for a monotherapy of hard-to-treat multiple myeloma.
基金Slovak grant agencies(APVV-19-0087,APVV-22-0172,DS-FR-22-0010 and VEGA 1/0029/22)are acknowledged for the financial support.J.J.,I.N.V.T.S.I.Š.acknowledge the financial support from the Grant Agency of the Czech Republic grant no.22-23760S+4 种基金This article was written with the generous support under the Operational Program Integrated Infrastructure for the project:“Strategic Research in the Field of SMART Monitoring,Treatment and Preventive Protection against Coronavirus(SARS-CoV-2)”project no.313011ASS8co-financed by the European Regional Development Fund.J.J.acknowledges financial support from an internal grant from Brno University of Technology CEITEC VUT-J-22-8049Furthermore,we acknowledge CzechNanoLab Research Infrastructure supported by MEYS CR(LM2023051)O.F.F.,I.N.and R.H.acknowledge the financial support from the institutional sources of the Department of Inorganic Chemistry,PalackýUniversity Olomouc,Czech Republic.O.F.F.acknowledges the support of MSTC Danube 8X23030 project.
文摘Two novel hexacoordinated Co(II)-based single-ion magnets were prepared and characterised.Both neutral complexes feature metal-centred coordination with one terminal and one bidentate nitrate anions along with tridentate derivatives of a 2,6-bis(1H-benzimidazole-2-yl)pyridine ligand containing either n-octyl(complex 1)or n-dodecyl(complex 2)chains.The presence of long aliphatic chains ensures their solubility in low polarity and volatile solvents frequently used for lithography patterning.This enabled the preparation of microstructural layers and patterns on technologically relevant substrates by easy-tohandle and low-cost wet lithographic techniques.On the other hand,attempts at surface deposition via sublimation were not successful due to thermal instability.
基金support of Slovak Grant Agencies(APVV-23-0006,APVV-22-0172,APVV-19-0087,VV-MVP-24-0039,VEGA 1/0029/22,DS-FR-22-0010)the project“Large Projects for Excellent Researchers”under the Recovery and Resilience Plan of the Slovak Republic(09I03-03-V03-00029)+1 种基金support from the Grant Agency of the Czech Republic Grant No.25-16980Ssupport from the Institutional Sources of the Department of Inorganic Chemistry,PalackýUniversity Olomouc,Czech Republic。
文摘Three variants of 2-(pyridine-2-yl)-1H-benzimidazole bidentate ligands,with distinct pentyl substituents(n-pentyl(L1),(2S)-2-methylbutyl(L2S),and(2R)-2-methylbutyl(L2R)),were synthesized and employed to prepare magnetically bistable cobalt_((II))and iron_((II))complexes.The cobalt_((II))complexes[Co(L1)(κ^(2)-NO_(3))_(2)(CH_(3)CN)](1),[Co(L2S)(κ^(2)-NO_(3))2(H_(2)O)](2S),[Co(L2R)(κ^(2)-NO_(3))2(H_(2)O)](2R)and[Co(L2)(κ^(2)-NO_(3))2(H_(2)O)](2rac)exhibit field supported slow relaxation of magnetisation,while the iron_((II))complexes[Fe(L2S)_(3)](CF_(3)SO_(3))_(2)·H_(2)O·CH_(3)NO_(2)·C_(5)H_(12)O(3S)and[Fe(L2S)_(3)]·1.5H_(2)O(3R)exhibit thermal spin crossover allocated above room temperature.Structural analysis revealed that the heptacoordinated cobalt_((II))complexes adopt a distorted pentagonal bipyramidal geometry,whereas the iron_((II))compounds contain hexacoordinated complex cations.Coordination compounds incorporating the chiral ligands L2S and L2R are optically active,with their enantiomeric relationship confirmed by circular dichroism spectroscopy.Computational studies provided insights into electron density distributions and bonding energetics(DFT and QT-AIM),predicted zero-field splitting parameters(CASSCF/NEVPT2),and quantified energies of the d-orbital,ligand field terms and their multiplets(via AILFT).Magnetic investigations of the cobalt_((II))complexes yielded experimental ZFS parameters and revealed distinct magnetization relaxation mechanisms:1 exhibits relaxation governed by a phonon bottle-neck process,whereas 2S and 2R involve a combination of Raman and direct relaxation processes.Notably,compounds 2S and 2R,despite being enantiomers and isostructural,exhibited distinct relaxation dynamics,attributable to differential phonon coupling pathways modulated by the chiral substituents.This is the first report demonstrating enantiomer-dependent slow relaxation of magnetisation behaviour in cobalt_((II))-based SMMs.These findings underscore the critical role of stereochemistry in modulating spin dynamics and magnetic bistability,providing design principles for future chiral magnetic materials.
基金financial support from the PalackýUniversity Olomouc project IGA_PrF_2022_006E.Č.was supported by the Slovak Research and Development Agency,contract no.APVV-22-0172 and APVV-18-0197。
文摘This article presents a series of six mononuclear Co(II)complexes 1-6 featuring ligands derived from a hexadentate Schiff base family,originating from the condensation of(2-formylphenoxy)acetic acid with various diamines.Notably,these complexes uniquely prefer a trigonal prism geometry,presenting a novel approach to synthesizing complexes with this distinctive shape.The compounds were characterized by elemental analysis,FT-IR spectroscopy,and single-crystal and powder XRD techniques.Furthermore,the magnetism was investigated by DC and AC magnetic measurements and also complemented by X-band EPR spectroscopy.The results reveal that the prepared complexes behave as field-induced single-molecule magnets,characterized by a substantial negative axial zero-field splitting D-parameter and spin reversal energetic barrier U_(eff) reaching values up to 72 K.The theoretical methods based on CASSCF/NEVPT2 calculations were applied to rationalize their magnetic properties.Moreover,these complexes hold promising potential for further functionalization,offering opportunities to enhance their properties,particularly towards developing zero-field single-molecule magnets as evidenced by the slow relaxation of magnetization in zero static magnetic field observed for the zinc-diluted complex 1Zn.
