• Journal of Microbiology and Biotechnology
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• 제33권10호
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• pp.1370-1375
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• 2023

In this study, we aimed to enhance the accumulation of chorismate (CHR) and anthranilate (ANT), key intermediates in the shikimate pathway, by modifying a shikimate over-producing recombinant strain of Corynebacterium glutamicum [19]. To achieve this, we utilized a CRISPR-driven genome engineering approach to compensate for the deletion of shikimate kinase (AroK) as well as ANT synthases (TrpEG) and ANT phosphoribosyltransferase (TrpD). In addition, we inhibited the CHR metabolic pathway to induce CHR accumulation. Further, to optimize the shikimate pathway, we overexpressed feedback inhibition-resistant Escherichia coli AroG and AroH genes, as well as C. glutamicum AroF and AroB genes. We also overexpressed QsuC and substituted shikimate dehydrogenase (AroE). In parallel, we optimized the carbon metabolism pathway by deleting the gntR family transcriptional regulator (IolR) and overexpressing polyphosphate/ATP-dependent glucokinase (PpgK) and glucose kinase (Glk). Moreover, acetate kinase (Ack) and phosphotransacetylase (Pta) were eliminated. Through our CRISPR-driven genome re-design approach, we successfully generated C. glutamicum cell factories capable of producing up to 0.48 g/l and 0.9 g/l of CHR and ANT in 1.3 ml miniature culture systems, respectively. These findings highlight the efficacy of our rational cell factory design strategy in C. glutamicum, which provides a robust platform technology for developing high-producing strains that synthesize valuable aromatic compounds, particularly those derived from the shikimate pathway metabolites.

• 전기학회논문지
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• 제67권7호
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• pp.917-927
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• 2018

High blood pressure causes various cardiovascular diseases and is associated with mortality. Periodic self-monitoring and recording of blood pressure is very helpful in preventing the occurrence of secondary diseases caused by hypertension. However, existing cuff-type blood pressure monitors have many limitations. As an alternative of that, a method of estimating the blood pressure by measuring the velocity change of the blood flow using the photo plethysmography is widely known. However, photo plethysmography have a low correlation with blood flow. So, we will propose an algorithm for estimating blood pressure using the relationship between velocity change of blood flow measured by magnetic field instead of photo plethysmography and electrocardiogram. For this purpose, First, we analyzed the correlation between photo plethysmography and magneto plethysmography. the correlation between MPG and PPG was r = 0.9449. Second, we compared estimated blood pressure and measured blood pressure. In the four experiment each result was r = 0.5737, r = 0.7863, r = 0.5669, and r = 0.7445.

• 대한의용생체공학회:의공학회지
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• 제27권6호
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• pp.370-375
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• 2006

The purpose of this work is to predict the systolic blood pressure (BP) during exercise from pulse transit time (PTT) for warning of possible danger. PTT was calculated as the time between R-peak of ECG and the peak of differential photoplethysmograph (PPG). For the PTT-BP model, we used regress equations from previous studies and 3 kinds of new models combining linear and nonlinear regress equation. The model parameters were estimated with the data measured under low to middle intensity exercise, and then was tested with the data measured under high intensity exercise. Predicted BP values after high intensity exercise were compared with those measured by cuff-type sphygmomanometer. The results showed that the error between measured and predicted values were acceptable for the monitoring BP. We tested PTT-BP models 1 month after the identification without further calibration. Models could predict the BP and the errors between measured and predicted BP were about 5mmHg. The suggested system is expected to be helpful in recognizing any danger during exercise.

• 대한의용생체공학회:의공학회지
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• 제27권3호
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• pp.83-88
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• 2006

A new method of measuring pulse arrival time (PAT), which is usually used for the estimation of systolic blood pressure, in an unconstrained manner using a chair, is proposed. The capacitive-coupled ECG (CC-ECG) measurement system and the air cushion with balancing tubes system were used for unconstrained PAT measurement. Firstly, the correlation between the standard PAT (S-PAT) from the photoplethysmography (PPG) and the PAT measured in an unconstrained manner (U-PAT) was evaluated. It was observed that U-PAT, which is the time delay from the R-peak of ECG to the steepest decent point of air cushion pressure wave, is significantly correlated with the S-PAT. Secondly, systolic blood pressure (SBP) measured by the radial tonometer is compared to the U-PAT. The ten-beat averaged U-PAT removed respiration effects and demonstrated a high intra-subject correlation with SBP in all participants. Finally, the tonometry SBP was estimated from these U-PAT values for one participant intermittently during half a day.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.178-186
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• 2007

This study is attempted to correct an error of electronic blood pressure meter with an optical sensor. In general, for a hospitalized patient, ECG, blood pressure, oxygen saturation, and respiration are basically measured to monitor the patient's condition. Opening of a blood vessel after it is occluded by pressurizing the cuff influences the blood flow of peripheral blood vessels as well as oscillation changes in the cuff. Blood vessels are occluded and peripheral blood flow disappears at cuff pressure above the examinee's blood pressure, while blood vessels are opened and peripheral blood flow appears again at cuff pressure under the examinee's blood pressure. Then Disappear-Appear Point Length(DAPL) of peripheral blood flow can be judged with the signal of peripheral blood flow, thus is available as a factor of error correction for electronic blood pressure meter. Also, systolic or diastolic blood pressure can be corrected with Appear-Point-Pressure(APP) of cuff pressure at a point where blood flow occurs and Appear-Maximum Pressure(AMP) of cuff pressure at the maximum amplitude point of peripheral blood flow after peripheral blood flow appears again. For verification, 27 examinees were selected, and their blood value was obtained through experimental procedure of 4 stages including induction of blood pressure change. The examinees were divided into two groups of experimental group and control group, regression analysis was conducted for experimental group, and correction of a blood pressure error was verified with optical signal by applying the regression equation calculated in experimental group to control group. As an experimental result, mean of the whole measurement errors was 5mmHg or more, which did not meet the standard fur blood pressure meter. As a result of correcting blood pressure measurements with data of DAPL, APP, and AMP as drawn out of PPG signal, systolic blood pressure, mean blood pressure, and diastolic blood pressure were $-0.6{\pm}4.4mmHg,\;-1.0{\pm}3.9mmHg$ and $-1.3{\pm}5.4mmHg$, respectively, indicating that mean of the whole measurement errors was greatly improved, and standard deviation was decreased.

• 대한화장품학회지
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• 제41권4호
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• pp.303-313
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• 2015

센텔라 아시아티카 정량추출물(TECA)은 병풀에서 얻은 난용성 추출물로 상처치유 및 항주름 물질로 알려져 있다. 본 연구에서는 TECA를 함유한 water in oil in water ($W_1/O/W_2$) 에멀젼 제조에 필요한 최적의 실험 조건을 찾기 위해 연구를 진행하였다. TECA의 용해도는 UV 흡광도계를 이용하였으며, 디프로필렌글라이콜(40.0 g), 에탄올(20.0 g) 및 정제수(10.0 g)의 조성에서 2.55 g의 TECA가 용해되는 것을 확인하였다. 에멀젼($W_1/O$, $W_1/O/W_2$)의 안정도에 영향을 미치는 요인에 대하여 조사하였다. $W_1/O$ 에멀젼의 제조하기 위한 최적의 수상 조건은 디프로필렌글라이콜 : 에탄올 : 정제수 : TECA가 40.0 : 20.0 : 10.0 : 2.5%(w/w), 유상 조건은 스쿠알란 : 세틸피이지/피피지-10/1디메치콘 : 세테아릴알코올이 22.5 : 4.0 : 1.0%(w/w)임을 확인하였다. $W_1/O/W_2$ 멀티에멀젼을 제조하기 위한 최적의 조건은 정제수 : $W_1/O$ 에멀젼 : 폴리소르베이트 80 : 카보머 : 트리에탄올아민의 비율이 55.8 : 40.0 : 4.0 : 0.1 : 0.1% (w/w)임을 확인하였다.

• 대한산업공학회지
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• 제43권2호
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• pp.127-134
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• 2017

For product or process design and development, it is common to optimize multiple responses (characteristics) based on experimental data. To determine optimal conditions, we need to design the experiment, estimate a proper model for each response, and optimize the multiple responses simultaneously. There are several techniques and many research results on optimizing multiple responses simultaneously, when the experimental data are available. However, the experimental design issue for optimizing multiple responses has not been discussed yet. This paper proposes some idea on how to plan screening design when requirements for multiple performance characteristics are to be met in developing new products. A screening design procedure is developed for securing the requirements of multiple responses. Initial design factors are classified into three categories; specific, non-conflicting common, and conflicting common. After screening experiments, follow-up design region search method is suggested with respect to the most unsatisfied or important response, or overall desirability. A case study on a synthesis of melamine formaldehyde resin is presented to illustrate the procedure and to show the validity of the approach.

• 한국컴퓨터정보학회논문지
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• 제28권12호
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• pp.1-7
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• 2023

딥러닝의 발전은 의료 분야에서도 다양한 응용을 가능하게 하고 있으며 이러한 애플리케이션 중에 심박수 측정은 개인의 건강을 관리하기 위한 필수적인 아이템이라 할 수 있다. 광혈류 측정을 이용한 기존 방법의 경우 스마트워치 같은 장비의 착용이 필수적이다. 그러나 최근 딥러닝 기술의 발전은 비침습식으로 원격에서 사용자의 얼굴 이미지를 분석하여 심박수를 높은 성능으로 측정가능하게 한다. 본 연구에서는 모바일 환경에서 사용 가능한 경량화된 심박수 추정 방법론을 제안한다. 이 방법론은 2D 컨볼루션에 기반한 특화된 2채널 네트워크 구조를 사용하여, 혈류와 근육 수축으로 인한 얼굴의 미세한 움직임과 색상 변화를 고려한다. 제안하는 네트워크 구조는 이미지 특성을 분석하는 인코더와 혈류량 파동을 예측하는 회귀 레이어로 구성되어있다. 이러한 복합적인 특성을 동시에 분석함으로써, 제한된 컴퓨팅 리소스를 가진 환경에서도 심박수를 정확하게 추정할 수 있다. 이 연구의 접근 방식은 침습적인 기술 없이도 심박수를 효과적으로 모니터링 할 수 있는 새로운 경로를 제공할 것으로 예상한다.

• 감성과학
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• 제10권3호
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• pp.463-470
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• 2007

공포에 대한 연구는 주로 불안과 공포 장애를 가진 환자들을 대상으로 수행되어왔으며, 공포를 불안의 특수한 한 형태라고 생각하여 불안과 공포에 대한 연구가 함께 이루어져왔다. 본 연구에서는 아동이 공포 정서를 경험하는 동안 나타나는 자율신경계 반응을 밝히고자 하였다. 초등학생을 대상으로 공포 정서를 유발하는 시청각 동영상을 제시하고 심리 반응과 자율신경계 반응을 측정하였다. 연구 결과, 공포 정서의 적합성 및 효과성은 80%이상으로 나타나 공포정서유발자극이 적절하고 효과적이었음을 알 수 있었다. 자율신경계 반응 분석 결과, 공포정서가 유발되는 동안 피부전도수준, 피부전도반응, 피부전도 반응의 수, 호흡주기관련 심박률 변화, 호흡수, 심박률분산의 고주파수 성분이 유의하게 증가하였고, 심장박동주기는 감소하였다. 공포 정서에 의해 야기된 자율신경계 반응에서는 불안수준이 높을수록 피부온도, 심박률, 호흡주기관련 심박률 변화가 큰 것으로 나타났다. 본 연구는 불안수준이 높은 아동일수록 공포 정서를 경험할 때 자율신경계 반응의 변화가 더 크다는 것을 나타낸다.