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41.
In patients with type 1 diabetes (T1D), compromised pancreatic β-cell functions are compensated through daily insulin injections or the transplantation of pancreatic tissue or islet cells. However, both approaches are associated with specific challenges. The transplantation of mesenchymal stem cells (MSCs) represents a potential alternative, as MSCs have tissue-forming capacity and can be isolated from various tissues. The human umbilical cord (hUC) is a good source of freely available MSCs, which can be collected through pain-free, non-invasive methods subject to minimal ethical concerns. We sought to develop a method for the in vitro generation of insulin-producing cells (IPCs) using MSCs. We examined the potential therapeutic uses and efficacy of IPCs generated from hUC-derived MSCs (hUC-IPCs) and human adipose tissue (hAD)-derived MSCs (hAD-IPCs) through in vitro experiments and streptozotocin (STZ)-induced C57BL/6 T1D mouse models. We discovered that compared to hAD-IPCs, hUC-IPCs exhibited a superior insulin secretion capacity. Therefore, hUC-IPCs were selected as candidates for T1D cell therapy in mice. Fasting glucose and intraperitoneal glucose tolerance test levels were lower in hUC-IPC-transplanted mice than in T1D control mice and hAD-IPC-transplanted mice. Our findings support the potential use of MSCs for the treatment of T1D. 相似文献
42.
When an inter-area mode dominates a low-frequency oscillation in a stressed condition, control of the active power flow of interface lines, with compensating devices, can effectively reduce the electromechanical power oscillations. In general, interface lines in which inter-area oscillations are large are considered to be good locations for installation of compensating devices. A sensitivity analysis with respect to change in active power flow can provide an important factor in electric power system operation. This paper proposes a new methodology to calculate the damping sensitivity with respect to change in active power flow, which can be useful for accurate selection of critical lines from the viewpoint of small-signal stability. In the proposed methodology, a damping sensitivity index is used to select the critical lines to damp power system oscillations. This paper describes how to derive the damping sensitivity for the selected mode and illustrates an example applying the proposed algorithm to a simple two-area system and the New England 39-bus test system. 相似文献
43.
Hyun-Chong Cho Kenneth Clint Slatton Carolyn R. Krekeler 《International journal of remote sensing》2013,34(24):9571-9597
To map the Earth's surface at remarkable resolution, Airborne Laser Swath Mapping (ALSM) instrument technology and subsequent algorithms have been used over the last several years. Since forested watersheds have commonly been problematic to study with remote sensing techniques, the ability of ALSM technology to densely sample ground elevations beneath forest canopies is especially considerable. Stream network detection from digital elevation models (DEMs) is a key role in modelling spatially distributed hydrological processes. To detect stream channels, we have developed two approaches. The first approach is based on an encoding of mathematical morphological operators. In the second approach, a composition of geodesic top-hat and bot-hat operations of different sizes is used in order to build a morphological profile (P M) that records the image structural information. The two proposed methods perform well in terms of detection results and classification accuracies. The second approach is more general than the first, but it also requires training and more computation. 相似文献
44.
We provide a rationale for open source project participation by studying the decision problems of the software programmers, whose types are different in terms of ability and intrinsic motivation. We find that motivations, both intrinsic and extrinsic, and the ability level positively affect the optimal level of effort exerted by the programmers in the open source project. In the commercial project, the programmers with higher ability exert much effort although their high level of effort is not compensated properly. Thus, the open source project might be more likely to attract capable and motivated programmers than the commercial project. 相似文献
45.
This study describes the development process of Kor-Factor, which is a novel composite evaluation index that was developed to promote Korean domestic academic journals. As more data accumulate, the Kor-Factor’s optimization process was modified in an attempt to address possible drawbacks of the original form; the result is presented in this study. This study compares Kor-Factor with the Impact Factor, which is the most well-known single element evaluation index. We found that Kor-Factor demonstrates a better power of differentiation and a greater capacity to reflect the reputability of key journals. The modified Kor-Factor, which has been developed through an optimization process, reveals a greater power of differentiation than the original Kor-Factor; however, the modified version has less capacity to reflect reputability. The evaluation elements of the modified Kor-Factor are better and are more evenly reflected on the index value than those of the original version. Finally, we propose the establishment of an appropriate data measurement period for the actual application of the index. 相似文献
46.
47.
Dong Kyun YimIn-Sun Cho Chan Woo LeeJun Hong Noh Hee Suk RohKug Sun Hong 《Optical Materials》2011,33(7):1036-1040
Novel whitish-blue phosphors based on a phosphate host matrix, γ-KCaPO4: Eu2+, were prepared by a conventional solid-state reaction method using slightly phosphorus deficient conditions and their photoluminescence properties were investigated. The concentration quenching process, temperature dependence of the luminescence and decay curve were also investigated. The γ-KCaPO4: Eu2+ phosphor was efficiently excited by UV-Visible light at wavelengths of 200-450 nm and exhibited a bright whitish-blue emission with a maximum peak wavelength of 473 nm. All of these characteristics suggest that the γ-KCaPO4: Eu2+ phosphors combined with red phosphors could be applicable to near UV-based white LEDs, i.e., only two kinds of phosphor powders are needed for the formation of white light. 相似文献
48.
Ki-Il Song Gye-Chun Cho 《International Journal of Rock Mechanics and Mining Sciences》2010,47(8):1274-1288
This study presents a simple but robust evaluation technique of the bonding state of shotcrete applied to tunnels using Impact-Echo (IE) method and thus explores the effect of the ground types, thickness of the shotcrete, undulating surfaces and impact sources on system vibration through numerical simulations based on the finite element method. All the signals obtained from numerical simulation for various conditions are analyzed at the frequency domain using Fourier transform (FT) and at the time–frequency domain using short-time Fourier transform (STFT). As the bonding condition worsens, the resonant frequency (fn) and the resonance duration (TR) increase and the geometric damping ratio (DG) decreases. The results of a comprehensive numerical analysis suggest that the shape of the contour in the time–frequency domain, the level of fn, and the TR and DG values can be used as effective indicators for the evaluation of the shotcrete thickness, ground type, and bonding state. Finally, this paper presents a procedure for evaluating the tunnel shotcrete state, the shotcrete thickness, and the ground type with the IE method coupled with Fourier transform and short-time Fourier transform. Limited field tests were also performed to verify the proposed evaluation chart for tunnel shotcrete states. 相似文献
49.
We have fabricated SOI CMOS active pixel image sensor with pinned photodiode on handle wafer. The structure of one pixel is a four-transistor type active pixel image sensor, which consists of a reset and a source follower transistor on seed wafer, and is comprised of a photodiode, a transfer gate, and a floating diffusion on handle wafer. The photodiode could be optimized for better quantum efficiency and low dark currents because the process of a photodiode on handle wafer is independent of that of transistors on seed wafer. Most of the wavelengths are absorbed within the visible range, because the optimized photodiode is located on the handle wafer. The response time of SOI CMOS active pixel sensor was about 2 times faster than that of bulk CMOS active pixel image sensor. 相似文献
50.
The rapid growth in electronic commerce places strong demands on business practices to meet customer needs in a timely and cost-effective manner. This article outlines some of the tools developed by Cisco to facilitate this growth while achieving excellent customer care and employee satisfaction. Attention is given to the steps Cisco has taken to organize to meet these dual objectives 相似文献