16 research outputs found
Supramolecular Chirality: Vesicle-to-Chiral Helix Transition of the Micelles Consisting of a Sugar-Bearing Calix[4]arene Surfactant
Supramolecular
self-assembly and the resulting chiral transfer
from the molecular level to the nanoscale is a major topic in modern
supramolecular chemistry. We synthesized a galactose-bearing calix[4]arene
surfactant (chiral) and mixed it with a primary amine-bearing analogue
(achiral). The mixture showed strong induced circular dichroism (ICD)
at an almost 3:2 molar ratio of the two surfactants, and exothermic
heat was observed upon mixing. The magnitude of Δ<i>H</i> was comparable to that of van der Waals interactions. This phenomenon
indicated that the ICD can be ascribed to the formation of a new supramolecular
assembly in which the stoichiometric interaction between the two molecules
leads to complexation and the resultant complex has chiral morphology.
Transmission electron microscopy and small-angle X-ray scattering
showed that the galactose-bearing surfactant forms vesicles, and the
mixing induces a transition from the vesicles to threadlike cylinders
with a diameter of ∼3.0 nm. We presume that these cylinder
are twisted because of chiral transfer from the chiral galactose moiety
and show ICD
Electrochemical Generation of Cationic Pd Catalysts and Application to Pd/TEMPO Double-Mediatory Electrooxidative Wacker-Type Reactions
We have developed an electrooxidative method for generating cationic palladium complexes [Pd(CH3CN)4][X]2 (X = BF4, PF6, and ClO4) from Pd(OAc)2 and several electrolytes bearing X groups in CH3CN. The system could be integrated into an electrochemical Wacker-type reaction. In the presence of a catalytic amount of TEMPO, the reaction proceeded smoothly to give the corresponding methyl ketones
DataSheet1_Subduction-zone parameters that control slab behavior at the 660-km discontinuity revealed by logistic regression analysis and model selection.PDF
The potential mechanisms that drive the behavior of subducted oceanic plates at the 660-km discontinuity are subject to debate. Here we conduct logistic regression analysis and model selection to determine the key subduction-zone parameters in natural subduction zones that discriminate the plate behavior along the discontinuity. We select the key variables based on three information criteria: leave-one-out cross-validation score (LOO), Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC). Among the 17 subduction-zone parameters analyzed, only the trench velocity, convergence rate, and trench width are selected in the simplest model that minimizes BIC. The thermal parameter and several other variables are also selected to minimize AIC and LOO. Our results suggest that a stagnant slab occurs along the 660-km discontinuity when there is a narrow oceanic plate and a retreating trench in natural subduction zones, which has also been modeled in previous numerical simulations. Neither the stress nor the deformation rate of the upper-plate margin is selected in the three optimal models, which suggests that back-arc spreading in natural subduction zones does not globally characterize plate behavior at the 660-km discontinuity, although back-arc spreading and a stagnant slab coincide in some numerical simulations. The combination of subduction-zone data analysis and numerical simulations will therefore provide deep insights into the dynamics of Earth’s deep interior.</p
Adjuvant Activity Enhanced by Cross-Linked CpG-Oligonucleotides in β‑Glucan Nanogel and Its Antitumor Effect
Cancer vaccine has the ability to
directly eradicate tumor cells
by creating and activating cytotoxic T lymphocytes (CTLs). To achieve
efficient CTL activity and to induce Th1 responses, it is essential
to administer an appropriate adjuvant as well as an antigen. CpG-ODN
is known as a ligand of Toll-like receptor 9 (TLR9) and strongly induces
Th1 responses. In our previous study, we developed a CpG-ODN delivery
system by use of the formation of complexes between ODN and a β-glucan
SPG, denoted as CpG/SPG, and demonstrated that CpG/SPG induces high
Th1 responses. In this study, we created a nanogel made from CpG/SPG
complexes through DNA–DNA hybridization (cross-linked (CL)-CpG).
Immunization with CL-CpG induced much stronger antigen-specific Th1
responses in combination with the antigenic protein ovalbumin (OVA)
than that with CpG/SPG. Mice preimmunized with CL-CpG and OVA exhibited
a long delay in tumor growth and an improved survival rate after tumor
inoculation. These immune inductions can be attributed to the improvement
of cellular uptake by the combination of increased size and the cluster
effect of the β-glucan recognition site in the nanogel structure.
In other words, the particle nature of CL-CpG, instead of the semiflexible
rod conformation of CpG/SPG, enhanced the efficacy of a cancer vaccine.
The present results indicate that CL-CpG can be used as a potent vaccine
adjuvant for the treatment of cancers and infectious diseases
Additional file 1 of Association between cumulative cisplatin dose and reproductive and sexual functions in patients with malignant ovarian germ cell tumors treated with bleomycin, etoposide, and cisplatin therapy: a case series study
Additional file 1. Relative dose intensity of BEP and resumption of menses in the two groups divided by age
Table1_Genesis and interaction of magmas at Nishinoshima volcano in the Ogasawara arc, western Pacific: new insights from submarine deposits of the 2020 explosive eruptions.XLSX
Sudden changes of eruption styles and magma compositions at arc volcanoes are enigmatic processes. Nishinoshima volcano, western Pacific, has had historical eruptions in 1973–1974 and from 2013 on and off to the present day. These eruptions were characterized by effusive Strombolian eruptions of andesite magmas until mid-June 2020, when they suddenly transitioned to violent explosive Strombolian eruptions that produced tephra fallout over a wide area. To understand this transition, we conducted marine surveys and sampling of the extensive submarine deposits of the tephra fallout. Our new data demonstrate that the full compositional range of the 2020 eruptions spans from basalt to dacite. We present evidence for magma mixing of newly injected basalt with andesite magmas. Nishinoshima consists of an andesitic main edifice surrounded by basaltic knolls: previous studies have shown that Nishinoshima andesite compositions can be generated by olivine fractionation of primary andesitic magmas that result from partial melting of hydrous mantle at relatively low pressures under the thin crust of the Ogasawara arc; knoll basalt compositions can be generated by partial melting of mantle at greater depths and were interpreted as older events of the volcano. We show that basalt magmas could have been generated throughout the entire history of Nishinoshima. In addition, we show that andesites from Nishinoshima and nearby Nishinoshima-Minami Knoll, which are only ∼8 km apart, have distinct subduction components. Together, these data improve our understanding of the diverse primary magmas responsible for the construction and continuing eruptive activity of an active island arc volcano.</p
On the Structural Origin of the Catalytic Properties of Inherently Strained Ultrasmall Decahedral Gold Nanoparticles
A new mechanism for reactivity of multiply twinned gold
nanoparticles
resulting from their inherently strained structure provides a further
explanation of the surprising catalytic activity of small gold nanoparticles.
Atomic defect structural studies of surface strains and quantitative
analysis of atomic column displacements in the decahedral structure
observed by aberration corrected transmission electron microscopy
reveal an average expansion of surface nearest neighbor distances
of 5.6%, with many strained by more than 10%. Density functional theory
calculations of the resulting modified gold <i>d-</i>band
states predict significantly enhanced activity for carbon monoxide
oxidation. The new insights have important implications for the applications
of nanoparticles in chemical process technology, including for heterogeneous
catalysis
On the Structural Origin of the Catalytic Properties of Inherently Strained Ultrasmall Decahedral Gold Nanoparticles
A new mechanism for reactivity of multiply twinned gold
nanoparticles
resulting from their inherently strained structure provides a further
explanation of the surprising catalytic activity of small gold nanoparticles.
Atomic defect structural studies of surface strains and quantitative
analysis of atomic column displacements in the decahedral structure
observed by aberration corrected transmission electron microscopy
reveal an average expansion of surface nearest neighbor distances
of 5.6%, with many strained by more than 10%. Density functional theory
calculations of the resulting modified gold <i>d-</i>band
states predict significantly enhanced activity for carbon monoxide
oxidation. The new insights have important implications for the applications
of nanoparticles in chemical process technology, including for heterogeneous
catalysis
Design and Synthesis of a <i>C</i><sub>3</sub> Symmetrical Phenalenyl Derivative with Three Oxo Groups by Regioselective Deoxygenation/Oxygenation
Tri-tert-butylated 4,7-dihydroxyphenalenone was
designed and synthesized from a corresponding 4,9-dimethoxyphenalenone
derivative by regioselective deoxygenation/oxygenation. The 4,7-dihydroxyphenalenone
derivative showed a chromic behavior accompanied by protonation and
deprotonation, giving monocation and dianion species, respectively,
and their C3 symmetric electronic structures
were elucidated by experimental and theoretical methods
Identification and Quantitative Assessment of Uremic Solutes as Inhibitors of Renal Organic Anion Transporters, OAT1 and OAT3
One
of the characteristics of chronic kidney disease (CKD) is the
accumulation of uremic solutes in the plasma. Less is known about
the effects of uremic solutes on transporters that may play critical
roles in pharmacokinetics. We evaluated the effect of 72 uremic solutes
on organic anion transporter 1 and 3 (OAT1 and OAT3) using a fluorescent
probe substrate, 6-carboxyfluorescein. A total of 12 and 13 solutes
were identified as inhibitors of OAT1 and OAT3, respectively. Several
of them inhibited OAT1 or OAT3 at clinically relevant concentrations
and reduced the transport of other OAT1/3 substrates <i>in vitro.</i> Review of clinical studies showed that the active secretion of most
drugs that are known substrates of OAT1/3 deteriorated faster than
the renal filtration in CKD. Collectively, these data suggest that
through inhibition of OAT1 and OAT3, uremic solutes contribute to
the decline in renal drug clearance in patients with CKD
