209 research outputs found
Solid-phase Synthesis of Oligosaccharides Using Novel Alkyne-type Linkers -Selection of Reactive Sites on the support by Sonogashira Reaction-
Two new alkyne-type linkers having alkynylmethyloxy moieties were elaborated for solid-phase synthesis of oligosaccharide. A propargyl glycoside-type linker between a sugar residue and a solid support was formed by the Sonogashira reaction of a propargyl glycoside with polymer-supported iodobenzene. A propargyl ester-type linker was also constructed by the same reaction of a 4-(proparygyloxycarbonyl)benzyl glycoside with the latter. Both linkers are stable against acids such as TFA but can be readily cleaved with this acid after conversion to the corresponding alkyne-cobalt complex by treatment with Co2(CO)8. The latter ester linker is generally advantageous in that mild cleavage liberates a proceed only at spatially reactive sites on the solid support where the reagent accesses readily, so that the subsequent reactions including glycosylation on solid phase proceeded smoothly to result in high total yields of the desired oligosaccharides
String-wall composites winding around a torus knot vacuum in an axion-like model
We study a simple axion-like model with a charged scalar and a
double-charged scalar of global symmetry. A particular feature
of our model is that a vacuum manifold is a torus knot. We consider a
hierarchical symmetry-breaking scenario that first condenses, giving
rise to cosmic -strings, and the subsequent condensation of leads
to domain wall formation spanning the -strings. We find that the
formation of the walls undergoes two different regimes depending on the
magnitude of an explicit breaking term of the relative between
and . One is the weakly interacting regime where the walls are
accompanied by another cosmic -strings. The other is the strongly
interacting regime where no additional strings appear. In both regimes, neither
a -string, a -string nor a wall alone is topological, but the
composite of an appropriate number of strings and walls as a whole is
topologically stable, characterized by the fundamental homotopy group of the
torus knot. We confirm the formation and the structure of the string-wall
system by first-principle cosmological two-dimensional simulations. We find
stable string-wall composites at equilibrium, where the repulsive force between
-strings and the tension of walls balances, and a novel reconnection of
the string-wall composites.Comment: 22 pages, 21 figure
Compulsory Repetitive Learning to Improve Student Achievement and Performance in Fundamental Subjects
We employ the methodology of “Compulsory Repetitive Learning” to improve student learning and performance in fundamental subjects. It is a challenge for many universities to intrinsically motivate students and it is a demanding issue that a large part of students do not sufficiently do homework. Here, we let students solve the problems associated with the teaching immediately following each lecture. Through the usage of “Compulsory Repetitive Learning”, each student as well as the subject teacher(s) could monitor and evaluate the quality of student learning and performance
Potential Cell-Based Therapies for Irreversibly Damaged Salivary Glands and Atrophic Alveolar Bone
BabyTigers 2001: Osaka Legged Robot Team
We have developed all kinds of motions such as walking, standing-up, and kicking towards Seattle. From a human designer’s point of view, it is easier to write strategies based on the geometric, global position data but seems less attractive. Then, we are attacking learning issues such as action selection [1] [2], observatio
Extremely Rare Breakdown of the Moyamoya Vessels Resulting in Intraventricular Hemorrhage after Direct Bypass Surgery in a Pediatric Patient with Moyamoya Disease
Revascularization surgery is established for both ischemic and hemorrhagic moyamoya disease (MMD), although hemorrhagic complication is a serious problem especially in adult MMD patients showing postoperative hyperperfusion. Herein, we present an extremely rare case with pediatric MMD showing intraventricular hemorrhage the day following direct bypass surgery, possibly due to a breakdown of the terminal branch of well-developed perforators working as moyamoya vessels. Clinicians should consider this rare complication after bypass surgery for MMD regardless of preoperative hemodynamics or patient age
Glucosylation of Sucrose Laurate with Cyclodextrin Glucanotransferase
Sucrose monolauroyl esters were found to serve as substrates for cyclodextrin glucanotransferase (CGTase)-catalyzed transglucosidation reactions, affording new sucrose esters that have an additional 1-3 glucose residues on the pyranose ring of the sucrose moiety in the ester
Long-term follow-up of endovascular coil embolization for cerebral aneurysms using three-dimensional time-of-flight magnetic resonance angiography.
OBJECTIVES: As endovascular treatment becomes more prevalent, aneurysm recurrence from neck remnants, recanalization, incomplete obliteration and bleeding remain major concerns. In the current analysis, we attempted to identify factors related to disease progression and clinical outcome in patients treated with coil embolization. METHODS: This study included 58 patients who underwent endovascular coil embolization for treatment of intracranial aneurysm. The result of embolization was evaluated with three-dimensional time-of-flight magnetic resonance angiography (TOF MRA) and classified as a complete occlusion, a residual neck (minor, central and marginal types), a residual dome (central and marginal types). Patients were followed up clinically and radiologically. Statistical analyses were performed to establish factors that influenced the occurrence of adverse events such as recurrence of aneurysm. RESULTS: Overall, the complete occlusion rate was 18.8%, the occurrence of a residual neck was 67.2%, and the residual dome rate was 14.1%. The mean clinical follow-up was 31.2 months. Recurrences were found in 18 aneurysms, and major recurrences were retreated with coiling or surgery. The post-treatment study revealed that the marginal-type aneurysm filling has a significant impact on outcome. Thus, perianeurysmal edema was correlated with recurrence of the aneurysm. CONCLUSIONS: Three-dimensional TOF MRA was a sensitive tool for visualizing residual filling of embolized aneurysm and is useful for long-term follow-up of patients
A novel method to identify Post-Aire stages of medullary thymic epithelial cell differentiation
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