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https://www.readbyqxmd.com/read/29458213/selective-targeting-and-degradation-of-doxorubicin-loaded-folate-functionalized-dna-nanocages
#1
Sofia Raniolo, Giulia Vindigni, Alessio Ottaviani, Valeria Unida, Federico Iacovelli, Antonio Manetto, Mariangela Figini, Lorenzo Stella, Alessandro Desideri, Silvia Biocca
Selective targeting is a crucial property of nanocarriers used for drug delivery in cancer therapy. We generated biotinylated octahedral DNA nanocages functionalized with folic acid through bio-orthogonal conjugation chemistry. Molecular modelling indicated that a distance of about 2.5 nm between folic acid and DNA nanocage avoids steric hindrance with the folate receptor. HeLa cells, a folate receptor positive tumour cell line, internalize folate-DNA nanocages with efficiency greater than 40 times compared to cells not expressing the folate receptors...
February 16, 2018: Nanomedicine: Nanotechnology, Biology, and Medicine
https://www.readbyqxmd.com/read/29457980/probing-the-chemistry-of-adhesion-between-a-316l-substrate-and-spin-on-glass-coating
#2
Felix Lampert, Shima Kadkhodazadeh, Takeshi Kasama, Kristian Vinter Dahl, Alexander Bruun Christiansen, Per Møller
Hydrogen silsesquioxane ([HSiO3/2]n) based "spin-on-glass" has been deposited on 316L substrate and cured in Ar/H2 gas atmosphere at 600 ºC to form a continuous surface coating with sub-micrometer thickness. The coating functionality depends primarily on the adhesion to the substrate, which is largely affected by the chemical interaction at the interface between the coating and the substrate. We have investigated this interface by transmission electron microscopy and electron energy loss spectroscopy...
February 19, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29457971/visible-light-photocatalysis-does-it-make-a-difference-in-organic-synthesis
#3
Leyre Marzo, Santhosh K Pagire, Oliver Reiser, Burkhard König
Visible light photocatalysis has evolved over the last decade into a widely used method in organic synthesis. For many important transformations, such as cross-coupling reactions, alpha-amino functionalizations, cycloadditions, ATRA reactions, or fluorinations, photocatalytic variants have been reported. In this review, we try to compare classical and photocatalytic procedures for selected classes of reactions and highlight their advantages and limitations. In many cases, the photocatalytic reactions proceed at milder reaction conditions, typically at room temperature, and stoichiometric reagents are replaced by simple oxidants or reductants, like air oxygen or amines...
February 19, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29457895/periodic-trends-in-actinyl-thio-crown-ether-complexes
#4
Shu-Xian Hu, Jing-Jing Liu, John K Gibson, Jun Li
In-cavity complexes and their bonding features between thio-crown (TC) ethers and f-elements are unexplored so far. In this paper, actinyl(VI) (An = U, Np, Pu, Am, and Cm) complexes of TC ethers have been characterized using relativistic density functional theory. The TC ether ligands include tetrathio-12-crown-4 (12TC4), pentathio-15-crown-5 (15TC5), and hexathio-18-crown-6 (18TC6). On the basis of the calculations, it is found that the "double-decker" sandwich structure of AnO2 (12TC4)2 2+ and "side-on" structure AnO2 (12TC4)2+ are changed to "insertion" structures for AnO2 (15TC5)2+ and AnO2 (18TC6)2+ due to increased size of the TC ether ligands...
February 19, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29457892/boronic-acid-catalyzed-regio-and-1-2-cis-stereoselective-glycosylation-of-unprotected-sugar-acceptors-via-s-n-i-type-mechanism
#5
Masamichi Tanaka, Akira Nakagawa, Nobuya Nishi, Kiyoko Iijima, Ryuichi Sawa, Daisuke Takahashi, Kazunobu Toshima
Regio- and 1,2-cis-stereoselective chemical glycosylation of unprotected glycosyl acceptors has been in great demand for the efficient synthesis of natural glycosides. However, simultaneously regulating these selectivities has been a long-standing problem in synthetic organic chemistry. In nature, glycosyl transferases catalyze regioselective 1,2-cis-glycosylations via the SN i mechanism, yet no useful chemical glycosylations based on this mechanism have been developed. In this paper, we report a highly regio- and 1,2-cis-stereoselective SN i-type glycosylation of 1,2-anhydro donors and unprotected sugar acceptors using p-nitrophenylboronic acid (10e) as a catalyst in the presence of water under mild conditions...
February 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29457884/unique-biochemical-and-sequence-features-enable-blub-to-destroy-flavin-and-distinguish-blub-from-the-flavin-monooxygenase-superfamily
#6
Amrita B Hazra, David P Ballou, Michiko E Taga
Vitamin B12 (cobalamin) is an essential micronutrient for humans that is synthesized only by a subset of bacteria and archaea. The aerobic biosynthesis of 5,6-dimethylbenzimidazole, the lower axial ligand of cobalamin is catalyzed by the "flavin destructase" enzyme BluB, which fragments reduced flavin mononucleotide following its reaction with oxygen to yield this ligand. BluB shares sequence and structural similarity with the flavin oxidoreductase superfamily, yet the flavin destruction process has remained elusive...
February 19, 2018: Biochemistry
https://www.readbyqxmd.com/read/29457862/peter-j-dunn-award-international-solvay-chair-in-chemistry-for-gernot-frenking-max-born-prize-for-angel-rubio-terrae-rarae-prize-for-rhett-kempe-frontiers-in-chemical-energy-science-award-for-karsten-reuter-and-also-in-the-news
#7
https://www.readbyqxmd.com/read/29457833/a-green-method-to-determine-vuv-185-nm-fluence-rate-based-on-hydrogen-peroxide-production-in-aqueous-solution
#8
Laxiang Yang, Mengkai Li, Wentao Li, James R Bolton, Zhimin Qiang
A mini-fluidic vacuum ultraviolet/ultraviolet (VUV/UV) photoreaction system (MVPS) was developed in our previous study. Based on the MVPS, a green method to determine VUV fluence rate has been developed using the production rate of H2 O2 when water is exposed to 185 nm VUV. The H2 O2 production followed pseudo-zero-order reaction kinetics well over the first 10 min of VUV/UV exposure. This new method was well calibrated with a standard cis-cyclooctene cis-trans photoisomerization actinometer as recommended by the International Union of Pure and Applied Chemistry...
February 19, 2018: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/29457822/a-nitrogen-rich-ligand-as-a-scaffold-for-slow-magnetic-relaxation-in-dysprosium-based-0d-and-1d-architectures
#9
Gabriel Brunet, Elena Sebastiao, Tomasz G Witkowski, Ilia Korobkov, Bulat Gabidullin, Muralee Murugesu
A recently designed nitrogen-rich ligand is successfully applied as a scaffold for lanthanide ions to show that the intricate chemistry of energetic materials can be combined with other fields of research, including that of molecular magnetism. Herein, we report the synthesis of two different types of molecular architectures using a single ligand template, in which the discrete monomer exhibits single-molecule magnet-like behaviour along with two well-isolated modes of magnetic relaxation.
February 19, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29457710/investigation-of-%C3%AE-mno-2-tunneled-structures-as-model-cation-hosts-for-energy-storage
#10
Lisa M Housel, Lei Wang, Alyson Abraham, Jianping Huang, Genesis D Renderos, Calvin D Quilty, Alexander B Brady, Amy C Marschilok, Kenneth J Takeuchi, Esther S Takeuchi
Future advances in energy storage systems rely on identification of appropriate target materials and deliberate synthesis of the target materials with control of their physiochemical properties in order to disentangle the contributions of distinct properties to the functional electrochemistry. This goal demands systematic inquiry using model materials that provide the opportunity for significant synthetic versatility and control. Ideally, a material family that enables direct manipulation of characteristics including composition, defects, and crystallite size while remaining within the defined structural framework would be necessary...
February 19, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29457690/carbon-atom-hybridization-matters-ultrafast-humidity-response-of-graphdiyne-oxides
#11
Lanqun Mao, Hailong Yan, Shuyue Guo, Fei Wu, Ping Yu, Huibiao Liu, Yuliang Li
Graphdiyne (GDY), a new kind of 2D carbon allotrope consisting of sp- and sp2-hybridized carbon atoms, has been envisaged to be promising in fundamental studies and various applications due to their unique atomic arrangement and electronic structure as well as surface chemistry. We herein for the first time find that graphdiyne oxide (GDO) exhibits an ultrafast humidity response with an unprecedented response speed (~ 7 ms), which is considered to benefit from the unique carbon hybridization of GDO that contains acetylenic bonds with stronger electron-withdrawing property than ethylenic bonds in GO...
February 19, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29457662/efficient-catalytic-enantioselective-hydroxyamination-of-%C3%AE-aryl-%C3%AE-cyanoacetates-with-2-nitrosopyridines
#12
Xiaoming Feng, Jingchuan Zhang, Kai Fu, Lili Lin, Yan Lu, Xiaohua Liu
The highly enantioselective totally N-selective hydroxyamination reaction of α-aryl-α-cyanoacetates with 2-nitrosopyridines was realized by using a chiral N,N'-dioxide/Mg(OTf)2 complex as catalyst, which enriches the nitroso chemistry. A variety of 2-cyano-2-[hydroxyl(pyrydin-2-yl)amino]acetates with quaternary stereocenters and potential antibacterial activities were obtained in excellent yields with good to excellent ee values under as low as 0.05 mol% catalyst loading. The products could be easily transformed to useful α-amino amides and 1,2-diamines...
February 19, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29457613/on-the-photocatalytic-cycle-of-water-splitting-with-small-manganese-oxides-and-the-roles-of-water-clusters-as-direct-sources-of-oxygen-molecules
#13
Kentaro Yamamoto, Kazuo Takatsuka
We theoretically studied the chemical principles behind the photodynamics of water splitting: 2H2 O + 4hν + M → 4H+ + 4e- + O2 + M. To comprehend this simple looking but very complicated reaction, the mechanisms of at least three crucial phenomena, among others, need to be clarified, each of which is supposed to constitute the foundation of chemistry: (i) charge separation (4H+ + 4e- ), (ii) the catalytic cycle for essentially the same reactions to be repeated by each of four photon absorptions with a catalyst M, and (iii) the generation of oxygen molecules of spin triplet...
February 19, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29457354/nitrogen-enriched-carbon-cnt-composites-based-on-schiff-base-networks-ultrahigh-n-content-and-enhanced-lithium-storage-properties
#14
Zhichang Xiao, Qi Song, Ruiying Guo, Debin Kong, Shanke Zhou, Xiaoxiong Huang, Rashid Iqbal, Linjie Zhi
To improve the electrochemical performance of carbonaceous anodes for lithium ion batteries (LIBs), the incorporation of both well-defined heteroatom species and the controllable 3D porous networks are urgently required. In this work, a novel N-enriched carbon/carbon nanotube composite (NEC/CNT) through a chemically induced precursor-controlled pyrolysis approach is developed. Instead of conventional N-containing sources or precursors, Schiff-base network (SNW-1) enables the desirable combination of a 3D polymer with intrinsic microporosity and ultrahigh N-content, which can significantly promote the fast transport of both Li+ and electron...
February 19, 2018: Small
https://www.readbyqxmd.com/read/29457335/relation-of-serum-uric-acid-to-an-exaggerated-systolic-blood-pressure-response-to-exercise-testing-in-men-with-normotension
#15
Sae Young Jae, Kanokwan Bunsawat, Yoon-Ho Choi, Yeon Soo Kim, Rhian M Touyz, Jeong Bae Park, Barry A Franklin
The authors investigated the hypothesis that high serum uric acid concentrations may be related to an exaggerated systolic blood pressure (SBP) response to maximal exercise testing in men with normotension, independent of potential confounding variables. In 4640 healthy men with normotension who underwent maximal treadmill exercise testing and fasting blood chemistry studies, including serum uric acid concentrations, an exaggerated SBP response, defined as SBP ≥ 210 mm Hg, was detected in 152 men (3.3%). After adjusting for potential confounders, participants in the highest quartile of serum uric acid (>6...
February 19, 2018: Journal of Clinical Hypertension
https://www.readbyqxmd.com/read/29457283/direct-visualization-of-the-reversible-o-2-o-redox-process-in-li-rich-cathode-materials
#16
Xiang Li, Yu Qiao, Shaohua Guo, Zhenming Xu, Hong Zhu, Xiaoyu Zhang, Yang Yuan, Ping He, Masayoshi Ishida, Haoshen Zhou
Conventional cathodes of Li-ion batteries mainly operate through an insertion-extraction process involving transition metal redox. These cathodes will not be able to meet the increasing requirements until lithium-rich layered oxides emerge with beyond-capacity performance. Nevertheless, in-depth understanding of the evolution of crystal and excess capacity delivered by Li-rich layered oxides is insufficient. Herein, various in situ technologies such as X-ray diffraction and Raman spectroscopy are employed for a typical material Li1...
February 19, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29457282/a-simple-general-synthetic-route-toward-nanoscale-transition-metal-borides
#17
Palani R Jothi, Kunio Yubuta, Boniface P T Fokwa
Most nanomaterials, such as transition metal carbides, phosphides, nitrides, chalcogenides, etc., have been extensively studied for their various properties in recent years. The similarly attractive transition metal borides, on the contrary, have seen little interest from the materials science community, mainly because nanomaterials are notoriously difficult to synthesize. Herein, a simple, general synthetic method toward crystalline transition metal boride nanomaterials is proposed. This new method takes advantage of the redox chemistry of Sn/SnCl2 , the volatility and recrystallization of SnCl2 at the synthesis conditions, as well as the immiscibility of tin with boron, to produce crystalline phases of 3d, 4d, and 5d transition metal nanoborides with different morphologies (nanorods, nanosheets, nanoprisms, nanoplates, nanoparticles, etc...
February 19, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29456886/heterogenic-transplantation-of-bone-marrow-derived-rhesus-macaque-mesenchymal-stem-cells-ameliorates-liver-fibrosis-induced-by-carbon-tetrachloride-in-mouse
#18
Xufeng Fu, Bin Jiang, Bingrong Zheng, Yaping Yan, Junfeng Wang, Yanchao Duan, Shanshan Li, Li Yan, Hong Wang, Bingbing Chen, Xiongbo Sang, Weizhi Ji, Ren-He Xu, Wei Si
Liver fibrosis is a disease that causes high morbidity and has become a major health problem. Liver fibrosis can lead to the end stage of liver diseases (livercirrhosisand hepatocellularcarcinoma). Currently, liver transplantation is the only effective treatment for end-stage liver disease. However, the shortage of organ donors, high cost of medical surgery, immunological rejection and transplantation complications severely hamper liver transplantation therapy. Mesenchymal stem cells (MSCs) have been regarded as promising cells for clinical applications in stem cell therapy in the treatment of liver diseases due to their unique multipotent differentiation capacity, immunoregulation and paracrine effects...
2018: PeerJ
https://www.readbyqxmd.com/read/29456858/enhanced-biostability-and-cellular-uptake-of-zinc-oxide-nanocrystals-shielded-with-a-phospholipid-bilayer
#19
B Dumontel, M Canta, H Engelke, A Chiodoni, L Racca, A Ancona, T Limongi, G Canavese, V Cauda
The widespread use of ZnO nanomaterials for biomedical applications, including therapeutic drug delivery or stimuli-responsive activation, as well as imaging, imposes a careful control over the colloidal stability and long-term behaviour of ZnO in biological media. Moreover, the effect of ZnO nanostructures on living cells, in particular cancer cells, is still under debate. This paper discusses the role of surface chemistry and charge of zinc oxide nanocrystals, of around 15 nm in size, which influence their behaviour in biological fluids and effect on cancer cells...
November 28, 2017: Journal of Materials Chemistry. B, Materials for Biology and Medicine
https://www.readbyqxmd.com/read/29456798/-18-f-radiolabeled-panobinostat-allows-for-positron-emission-tomography-guided-delivery-of-a-histone-deacetylase-inhibitor
#20
Harikrishna Kommidi, Umberto Tosi, Uday B Maachani, Hua Guo, Christopher S Marnell, Benedict Law, Mark M Souweidane, Richard Ting
Histone deacetylase (HDAC) inhibition is becoming an increasingly popular approach to treat cancer, as HDAC overexpression is common in many malignancies. The blood-brain barrier (BBB) prevents systemically delivered drugs from reaching brain at effective concentration, making small-molecule-HDAC inhibition in brain tumors particularly challenging. To circumvent the BBB, novel routes for administering therapeutics are being considered in the clinic, and a need exists for drugs whose deliveries can be directly imaged, so that effective delivery across the BBB can be monitored...
February 8, 2018: ACS Medicinal Chemistry Letters
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