Seoul National University

About: Seoul National University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Catalysis. The organization has 65879 authors who have published 138759 publications receiving 3715170 citations. The organization is also known as: SNU & Seoul-dae.

Intensive Blood-Pressure Lowering in Patients with Acute Cerebral Hemorrhage

Abstract: BackgroundLimited data are available to guide the choice of a target for the systolic blood-pressure level when treating acute hypertensive response in patients with intracerebral hemorrhage. MethodsWe randomly assigned eligible participants with intracerebral hemorrhage (volume, <60 cm3) and a Glasgow Coma Scale (GCS) score of 5 or more (on a scale from 3 to 15, with lower scores indicating worse condition) to a systolic blood-pressure target of 110 to 139 mm Hg (intensive treatment) or a target of 140 to 179 mm Hg (standard treatment) in order to test the superiority of intensive reduction of systolic blood pressure to standard reduction; intravenous nicardipine to lower blood pressure was administered within 4.5 hours after symptom onset. The primary outcome was death or disability (modified Rankin scale score of 4 to 6, on a scale ranging from 0 [no symptoms] to 6 [death]) at 3 months after randomization, as ascertained by an investigator who was unaware of the treatment assignments. ResultsAmong 1000...

Engineering of functional, perfusable 3D microvascular networks on a chip

Abstract: Generating perfusable 3D microvessels in vitro is an important goal for tissue engineering, as well as for reliable modelling of blood vessel function. To date, in vitro blood vessel models have not been able to accurately reproduce the dynamics and responses of endothelial cells to grow perfusable and functional 3D vascular networks. Here we describe a microfluidic-based platform whereby we model natural cellular programs found during normal development and angiogenesis to form perfusable networks of intact 3D microvessels as well as tumor vasculatures based on the spatially controlled co-culture of endothelial cells with stromal fibroblasts, pericytes or cancer cells. The microvessels possess the characteristic morphological and biochemical markers of in vivo blood vessels, and exhibit strong barrier function and long-term stability. An open, unobstructed microvasculature allows the delivery of nutrients, chemical compounds, biomolecules and cell suspensions, as well as flow-induced mechanical stimuli into the luminal space of the endothelium, and exhibits faithful responses to physiological shear stress as demonstrated by cytoskeleton rearrangement and increased nitric oxide synthesis. This simple and versatile platform provides a wide range of applications in vascular physiology studies as well as in developing vascularized organ-on-a-chip and human disease models for pharmaceutical screening.

Ultrahigh Mobility in Polymer Field-Effect Transistors by Design

Abstract: In this article, the design paradigm involving molecular weight, alkyl substituents, and donor−acceptor interaction for the poly[2,6-(4,4-bis-alkyl-4H-cyclopenta[2,1-b;3,4-b′]-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (cyclopentadithiophene−benzothiadiazole) donor−acceptor copolymer (CDT−BTZ) toward field-effect transistors (FETs) with ultrahigh mobilities is presented and discussed. It is shown that the molecular weight plays a key role in improving hole mobilities, reaching an exceptionally high value of up to 3.3 cm2 V−1 s−1. Possible explanations for this observation is highlighted in conjunction with thin film morphology and crystallinity. Hereby, it is found that the former does not change, whereas, at the same time, crystallinity improved with ever growing molecular weight. Furthermore, other important structural design factors such as alkyl chain substituents and donor−acceptor interaction between the polymer backbones potentially govern intermolecular stacking distances crucial for charge tr...

Large amplitude oscillatory shear as a way to classify the complex fluids

Abstract: Rheological properties of some polymer solutions in both the linear and non-linear regions have been investigated. The solutions include poly(vinyl alcohol) solution (with and without sodium borate), hyaluronic acid solution, and xanthan gum solution; some of which form microstructures depending on their deformation history, and thus can be classed as complex fluids. Among the rheological properties, the large amplitude oscillatory shear (LAOS) behavior was found to be very sensitive to the interactions or the shear-induced formation of microstructures. Depending on the interactions between the microstructures, it was found that there exist at least four types of LAOS behavior: type I, strain thinning (G′, G″ decreasing); type II, strain hardening (G′, G″ increasing); type III, weak strain overshoot (G′ decreasing, G″ increasing followed by decreasing); type IV, strong strain overshoot (G′, G″ increasing followed by decreasing). It is suggested that the LAOS behavior can be effectively used as a tool for classifying the complex fluids.