Comparative Studies of Pulsatile and Nonpulsatile Blood Flow during Cardiopulmonary Bypass (박동류 및 비박동류에 의한 체외순환의 비교)
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- Journal of Chest Surgery
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- v.18 no.2
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- pp.182-192
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- 1985
[here are so many reports that pulsatile blood flow provides physiologic organ perfusions during cardiopulmonary bypass. So, we compared the recent 30 cases undergoing cardiac surgery by Cobe-Stckert pulsatile roller pump with another 30 cases by Polystan nonpulsatile roller pump. Pulsatile flow was applied during aortic-cross clamping period when synchronized to internal EKG simulator, and perfusion mode was changed to continuous nonpulsatile flow after declamping of aorta. Age, sex, weight, and disease entities were comparable and operative techniques were similar between two groups. 1. There were no differences in average ACC time, ECC time, and Operation time. 2. Postoperative artificial respiration time was 6hrs 30mins in nonpulsatile group and 4hrs 48mins in pulsatile group, and detubation time after ventilator weaning was 2hrs 44mins in nonpulsatile group and 1hrs 43mins in pulsatile group. 3. Average pulse pressure was 8mmHg in nonpulsatile group and 55mmHg in pulsatile group, and a mean arterial pressure was 66.0mmHg in nonpulsatile group and 60.7mmHg in pulsatile group. 4. Mean urine-output during ACC;ECC period was 9.717.3;9.913.2ml/kg/hr in nonpulsatile group and 14.215.0;15.817.5 in pulsatile group [p<0, 05], and thereafter progressive decrease of differences in urine output between two groups until POD 2, and lesser amounts of diuretics was needed in pulsatile group during same postoperative period. Serum BUN/Cr level showed no specific difference and urine concentration power was well preserved in both groups. 5. Plasma proteins and other Enzymes showed no differences between two groups, but serum GOT/GPT level was higher in nonpulsatile group till POD 2. 6. Serum Electrolytes showed no differences between two groups. 7. WBC, RBC, Platelet counts, Hgb and Hct were not different and Coagulogram was well preserved in both groups. 8. Plasma free Hgb level was 7.09mg% in pulsatile group compared with 3.48mg% in pulsatile group on POD 1 but was normalized on POD 2. Gross hemoglobinuria after ECC was noted in 6 cases [20%] of pulsatile group and 4 cases [13%] of nonpulsatile group. 9. In both groups, most patients were included in NYHA class III to IV [28 cases;93% in nonpulsatile group, 22 cases;73% in pulsatile group] preoperatively, and well improved to class I to 11[22 cases; 73% in nonpulsatile group, 30 cases; 100% in pulsatile group] postoperatively. There were 7 operative mortalities in nonpulsatile group only, which were 5 cases of TOF with hepatic failure, 1 case of multiple VSDs with low out-put syndrome, and 1 case of mitral valvular heart disease with cardiomyopathy. We concluded that the new, commercially available Cobe-Stckert pulsatile roller pump device was safe, simple, and reliable.
We designed and fabricated a bidirectional optical transceiver module for low cost access network. An integrated chip forming a pin-PD on an 1.3 urn FP-LD was assembled by flip-chip bonding on a Si optical bench, a single mode fiber with an angled end facet was aligned passively with the integrated chip on V-groove of Si-optical bench. Gaussian beam theory was applied to evaluate the coupling coefficients as a function of some parameters such as alignment distance, angle of fiber end facet, vertical alignment error. The theory is also used to search the bottle-neck between transmittance and receiving coupling efficiency in the bi-directional optical system. Tn this paper, we confirmed that reduction of coupling efficiency by the vertical alignment error between laser beam and fiber core axis can be compensated by controlling the fiber facet angle. In the fabrication of sub-module, a'||'&'||' we made such that the fiber facet have a corn shape with an angled facet only core part, the reflection of transmitted laser beam from the fiber facet could be minimized below -35 dE in alignment distance of 2: 30 /J.m. In the same condition, transmitted output power of -12.1 dEm and responsivity of 0.2. AIW were obtained.
In this paper, a wireless video streaming system is designed and implemented for TV white space applications. It consists of a RF transceiver module, a digital modem, a camera, and a LCD screen. A VGA resolution video is captured by a camera, modulated by modem, and transmitted by RF transceiver module, and finally displayed at a destination 2.6-inch LCD screen. The RF transceiver is based on direct-conversion architecture. Image leakage is improved by low pass filtering LO, which successfully covers the TVWS. Also, DC offset problem is solved by current steering techniques which control common mode level at DAC output node. The output power of the transmitter and the minimum sensitivity of the receiver is +10 dBm and -82 dBm, respectively. The channel bandwidth is tunable among 6, 7 and 8 MHz according to regulations and standards. Digital modem is realized in Kintex-7 FPGA. Data rate is 9 Mbps based on QPSK and 512ch OFDM. A VGA video is successfully streamed through the air by using the developed TV white-space RF communication module.
In this paper, we took the basic experiment in order to explore the characteristics of optical CT(optical current transformer) for measuring high current in a superhigh voltage condition using faraday effect and wrote that. We used the 1,310[nm] Laser Diode for the source of light and PIN-Photodiode for receiver. The transmission line of light was composed of the single-mode fiber of 30[m] which could maintain the state of polarization in the optical fiber. The range of current was from 400[A] to 1300[A]. In addition, the temperature ranged from
Reducing power consumption to extend network lifetime is one of the most important challenges in designing wireless sensor networks. One promising approach to conserving system energy is to keep only a minimal number of sensors active and put others into low-powered sleep mode, while the active sensors can maintain a connected covet set for the target area. The problem of computing such minimum working sensor set is NP-hard. In this paper, a centralized Voronoi tessellation (CVT) based approximate algorithm is proposed to construct the near optimal cover set. When sensor's communication radius is at least twice of its sensing radius, the covet set is connected at the same time; In case of sensor's communication radius is smaller than twice of its sensing radius, a connection scheme is proposed to calculate the assistant nodes needed for constructing the connectivity of the cover set. Finally, the performance of the proposed algorithm is evaluated through theoretical analysis and extensive numerical experiments. Experimental results show that the proposed algorithm outperforms the greedy algorithm in terms of the runtime and the size of the constructed connected cover set.
Air pollution caused by industrial development has become a level that can seriously threaten human health. In general, indoor air pollution is considered to be lower than outdoors, but modern people live indoors most of the time, thus it is essential to keep the indoor air quality comfortable in order to take care of one's own health and improve the quality of life. Therefore, the development of an indoor environment management platform using Internet of Things and data processing technology, which is currently drawing attention, is considered a very meaningful study. In this paper, we designed an IoT-based management platform that can remotely monitor and control indoor environments. In addition, the functions of the IoT terminal, gateway, and data server constituting the platform were implemented using open source and open libraries, and all functional operations were also verified. In particular, the IoT terminal and the gateway in this paper exchange data using BLE communication, so they can operate with relatively low power and since the gateway uses the BLE Advertising mode, it has the advantage of automatically recognizing IoT terminals that have not been previously configured.
The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70
The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70
Against the backdrop of the increasing trend towards economic globalisation, many international firms are indicating that decisions on how to enter foreign markets remains one of the key strategic challenges confronting them. Despite the rich body of literature on the topic, the fact that these challenges have continued to dominate global marketing strategy discourses point to someevident lacunae. Accordingly, this paper considers the variables, categorised in terms of firm contexts (standardisation, market research, competition, structure, competitive advantage) and host country-contexts (economic development, cultural differences, regulation and political risk), which influence the degree of involvement of UK companies in overseas markets. Following hypotheses were drawn from literature review: H1: The greater the level of competition, the higher the degree of involvement in the overseas market. H2: The more centralised the firm's organisation structure, the higher the degree of involvement in the overseas market. H3a: The adoption of a low cost-approach to competitive advantage will lead to a higher degree of involvement. H3b: The adoption of an innovation-approach to competitive advantage will lead to a higher degree of involvement. H3c: The adoption of a market research approach to competitive advantages will lead to a higher degree of involvement. H3d: The adoption of a breadth of strategic target-approach to competitive advantage will lead to a lower degree of involvement. H4: The higher the degree of standardisation of the international marketing mix the higher the degree of involvement. H5: The greater the degree of economic development in the host market, the higher the degree of involvement. H6: The greater the cultural differences between home and host countries, the lower the degree of involvement. H7: The greater the difference in regulations between the home country and the host country, the lower the degree of involvement. H8: The higher the political risk in the host country, the lower the degree of involvement. A questionnaire instrument was constructed using, wherever possible, validated measures of the concepts to serve the aims of this study. Following two sets of mailings, 112 usable completed questionnaires were returned. Correlation analysis and multiple regression analysis were used to analyze data. Statistically, the paper suggests that factors relating to the level of competition, competitive advantages and economic development are strong in influencing foreign market involvements. On the other hand, unexpectedly, cultural factors (especially individualism/collectivism and low and high power distance dimensions) proved to have weak moderating effects. The reason for this, in part, is due to the pervading forces of globalisation and the attendant effect on global marketing. This paper has contributed to the general literature in a way that point to two mainimplications. First, with respect to research on national systems, the study may hold out some important lessons especially for developing nations. Most of these nations are known to be actively seeking to understand what it takes to attract foreign direct investment, expand domestic market and move their economies from the margin to the mainstream global economy. Second, it should be realised that competitive conditions remain in constant flux (even in mature industries and mature economies). This implies that a range of home country factors may be as important as host country factors in explaining firms' strategic moves and the degree of foreign market involvement. Further research can consider the impact of the home country environment on foreign market involvement decisions. Such an investigation will potentially provide further perspectives not only on the influence of national origin but also how home country effects are confounded with industry effects.