• Title/Summary/Keyword: Gas detector

Search Result 573, Processing Time 0.029 seconds

THE CURRENT STATUS OF BIOMEDICAL ENGINEERING IN THE USA

  • Webster, John G.
    • Proceedings of the KOSOMBE Conference
    • /
    • v.1992 no.05
    • /
    • pp.27-47
    • /
    • 1992
  • Engineers have developed new instruments that aid in diagnosis and therapy Ultrasonic imaging has provided a nondamaging method of imaging internal organs. A complex transducer emits ultrasonic waves at many angles and reconstructs a map of internal anatomy and also velocities of blood in vessels. Fast computed tomography permits reconstruction of the 3-dimensional anatomy and perfusion of the heart at 20-Hz rates. Positron emission tomography uses certain isotopes that produce positrons that react with electrons to simultaneously emit two gamma rays in opposite directions. It locates the region of origin by using a ring of discrete scintillation detectors, each in electronic coincidence with an opposing detector. In magnetic resonance imaging, the patient is placed in a very strong magnetic field. The precessing of the hydrogen atoms is perturbed by an interrogating field to yield two-dimensional images of soft tissue having exceptional clarity. As an alternative to radiology image processing, film archiving, and retrieval, picture archiving and communication systems (PACS) are being implemented. Images from computed radiography, magnetic resonance imaging (MRI), nuclear medicine, and ultrasound are digitized, transmitted, and stored in computers for retrieval at distributed work stations. In electrical impedance tomography, electrodes are placed around the thorax. 50-kHz current is injected between two electrodes and voltages are measured on all other electrodes. A computer processes the data to yield an image of the resistivity of a 2-dimensional slice of the thorax. During fetal monitoring, a corkscrew electrode is screwed into the fetal scalp to measure the fetal electrocardiogram. Correlations with uterine contractions yield information on the status of the fetus during delivery To measure cardiac output by thermodilution, cold saline is injected into the right atrium. A thermistor in the right pulmonary artery yields temperature measurements, from which we can calculate cardiac output. In impedance cardiography, we measure the changes in electrical impedance as the heart ejects blood into the arteries. Motion artifacts are large, so signal averaging is useful during monitoring. An intraarterial blood gas monitoring system permits monitoring in real time. Light is sent down optical fibers inserted into the radial artery, where it is absorbed by dyes, which reemit the light at a different wavelength. The emitted light travels up optical fibers where an external instrument determines O2, CO2, and pH. Therapeutic devices include the electrosurgical unit. A high-frequency electric arc is drawn between the knife and the tissue. The arc cuts and the heat coagulates, thus preventing blood loss. Hyperthermia has demonstrated antitumor effects in patients in whom all conventional modes of therapy have failed. Methods of raising tumor temperature include focused ultrasound, radio-frequency power through needles, or microwaves. When the heart stops pumping, we use the defibrillator to restore normal pumping. A brief, high-current pulse through the heart synchronizes all cardiac fibers to restore normal rhythm. When the cardiac rhythm is too slow, we implant the cardiac pacemaker. An electrode within the heart stimulates the cardiac muscle to contract at the normal rate. When the cardiac valves are narrowed or leak, we implant an artificial valve. Silicone rubber and Teflon are used for biocompatibility. Artificial hearts powered by pneumatic hoses have been implanted in humans. However, the quality of life gradually degrades, and death ensues. When kidney stones develop, lithotripsy is used. A spark creates a pressure wave, which is focused on the stone and fragments it. The pieces pass out normally. When kidneys fail, the blood is cleansed during hemodialysis. Urea passes through a porous membrane to a dialysate bath to lower its concentration in the blood. The blind are able to read by scanning the Optacon with their fingertips. A camera scans letters and converts them to an array of vibrating pins. The deaf are able to hear using a cochlear implant. A microphone detects sound and divides it into frequency bands. 22 electrodes within the cochlea stimulate the acoustic the acoustic nerve to provide sound patterns. For those who have lost muscle function in the limbs, researchers are implanting electrodes to stimulate the muscle. Sensors in the legs and arms feed back signals to a computer that coordinates the stimulators to provide limb motion. For those with high spinal cord injury, a puff and sip switch can control a computer and permit the disabled person operate the computer and communicate with the outside world.

  • PDF

Relationships between Fatty Acids and Tocopherols of Conventional and Genetically Modified Peanut Cultivars Grown in the United States (미국산 전통품종과 유전자 재조합 땅콩품종의 지방산과 토코페롤의 상관관계)

  • Shin, Eui-Cheol
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.42 no.10
    • /
    • pp.1618-1628
    • /
    • 2013
  • Relationships between fatty acids and tocopherols in conventional and genetically modified peanut cultivars were studied by gas chromatography with flame ion detector and high performance liquid chromatography with fluorescence detection. Eight fatty acids and four tocopherol isomers in the sample set were identified and quantified. Oleic acid and linoleic acid are major fatty acids and the ratio of oleic and linoleic acids ranged from 1.11 to 16.26. Tocopherols contents were 6.76 to 12.24 for ${\alpha}$-tocopherol (T), 0.08 to 0.39 for ${\beta}$-T, 5.28 to 15.02 for ${\gamma}$-T, and 0.17 to 1.17 mg/100 g for ${\delta}$-T. Correlation coefficient (r) for fatty acids and tocopherols indicated a strong inverse relationship between oleic & linoleic acids (r=-0.97, P<0.05) and positive relationships between palmitic & linoleic acids (r=0.95, P<0.05) and ${\gamma}$-T & ${\delta}$-T (r=0.83, P<0.05). Principal component analysis (PCA) of fatty acids and tocopherols gave four significant principal components (PCs, with eigenvalues>1), which together account for 85.49% of the total variance in the data set with PC1 and PC2 contributing 45.27% and 21.33% of the total variability, respectively. Eigen analysis of the correlation matrix loadings of the four significant PCs revealed that PC1 was mainly contributed by palmitic, oleic, linoleic, and gondoic acids, while PC2 was by behenic acid, ${\beta}$-T, and ${\gamma}$-T. The score plot generated by PC1-PC2 identified sample clusters in the two spatial planes based on the oleic and linoleic acids. The score plot PC3-PC4 didn't separate sample groups.

Comparison of Dosimetry Protocols in High Energy Electron Beams (고에너지 전자선에 대한 표준측정법간의 비교)

  • 박성용;서태석;김회남;신동오;지영훈;군수일;이길동;추성실;최보영
    • Progress in Medical Physics
    • /
    • v.9 no.4
    • /
    • pp.267-276
    • /
    • 1998
  • Any detector inserted into a phantom should have such a geometry that it caused as small as possible perturbation of the electron fluence. Plane parallel chambers meet this requirement better than other chambers of configurations. IAEA protocol recommends the use of plane parallel chambers for this reason. However, the cylindrical chambers are widely used for convenient. The purpose of this study is to evaluate the absorbed dose due to the differences of four different dosimetry protocols such as IAEA protocol using cylindrical chamber, TG 21 protocol using cylindrical chamber, Markus protocol using plane parallel chamber, and TG 39 report for the calibration of plane parallel chamber in electron beams. Depth-ionization measurements for the electron beams of nominal energy 6, 9, 12, 15, and 18 MeV from Siemens accelerator with a 10$\times$10 cm$^2$ field size were made using a radiation field analyser with 0.125 cc ion chamber. Dosimetric measurements by IAEA and TG 21 protocol were made with a farmer type ionization chamber in solid water for each electron energy, respectively. Dosimetric measurements by Markus protocol were made with a plane parallel ionization chamber in solid water for each electron energy, respectively. The cavity-gas calibration factor for the plane parallel chamber was obtained with the use of 18 MeV electron beam as guided by TG 39 report. Dosimetric measurements by TG 39 were performed with a plane parallel ionization chamber in solid water for each electron energy, respectively. For all the energies and protocols, measurements were made along the central axis of the distance of 100 cm (SSD = 100 cm) with 10$\times$10 cm$^2$ field size at the depth of d$_{max}$ for each electron beam, respectively. In the case of 18 MeV, the discrepancy of 0.9 % between IAEA and TG 21 was found and the two protocols were agreed within 0.7 % for other energies. In the case of 18 MeV and 6 MeV, the discrepancies of $\pm$ 0.8 % between Markus and TG 39 was found, respectively and the two protocols were agreed within 0.5 % for other energies. Since the discrepancy of 1.6 % between cylindrical and plane parallel chamber was found for 18 MeV, it is suggested to get the calibration factor using other method as guided. by TG 39.9.

  • PDF

Evaluation of Odors and Odorous Compounds from Liquid Animal Manure Treated with Different Methods and Their Application to Soils (액상 가축분뇨의 처리 및 토양환원에 따른 악취 및 악취물질의 평가)

  • 고한종;최홍림;김기연;이용기;김치년
    • Journal of Animal Science and Technology
    • /
    • v.48 no.3
    • /
    • pp.453-466
    • /
    • 2006
  • To comply with stricter regulations provoked by increasing odor nuisance, it is imperative to practice effective odor control for sustainable livestock production. This study was conducted to assess odor and odorous compounds emitted from liquid animal manure with different treatment methods such as Fresh Manure(without treatment, FM), Anaerobic Digestion(AD) and Thermophilic Aerobic Digestion(TAD) and their application to soil. Air samples were collected at the headspace of liquid manure, upland and paddy soil, and analyzed for odor intensity and offensiveness using an olfactometry; odor concentration index using odor analyser; nitrogen-containing compound such as ammonia(NH3) using fluorescence method; and sulfur containing compounds such as hydrogen sulfide(H2S), methyl mercaptan(MeSH), dimethyl sulfide(DMS) and dimethyl disulfide(DMDS) using gas chromatography-pulsed flame photometric detector, respectively. Odor intensity, offensiveness and concentration index from TAD liquid manure was statistically lower than those from FM and AD(p<0.01). Mean concentrations of H2S, MeSH, DMS, DMDS and NH3 were 65.93ppb, 18.55ppb, 5.26ppb, 0.33ppb and 10.57ppm for liquid manure with AD; and 5.15ppb, 0.97ppb, 0.80ppb, 0.56ppb and 1.34ppm for liquid manure with TAD, respectively. More than 60% of malodorous compounds related to nitrogen and sulfur were removed by heterotrophic microorganisms during TAD treatment. When liquid manure was applied onto upland and paddy soil, NH3 removal efficiencies ranged from 51 to 94% and 22 to 91% for AD and TAD liquid manure, respectively. The above results show that liquid manure with TAD is superior to AD and FM with respect to the odor reduction and odor problem caused by land applied liquid manure is directly related to the degree of odor generated by the manure treatment method.

Monitoring Methylmercury in Abyssal Fish (심해성 어류 중 메틸수은 모니터링)

  • Kim, Seong-Cheol;Jang, Jin-Wook;Kim, Hyun-Ah;Lee, Sang-Ho;Jung, Young-Ji;Kim, Ji-Yeon;Ahn, Jong-Hoon;Park, Eun-Hye;Ko, Yong-Seok;Kim, Dong-Sul;Kim, Sang-Yub;Jang, Young-Mi;Kang, Chan-Soon
    • Korean Journal of Food Science and Technology
    • /
    • v.42 no.4
    • /
    • pp.383-389
    • /
    • 2010
  • The aim of this study was to determine the methylmercury (MeHg) levels in abyssal fish species. The MeHg in the fishes was extracted with hydrochloric acid and toluene and then purified using an L-cysteine solution. The extract was analyzed with a gas chromatography-electron capture detector (GC-${\mu}ECD$) with a thermon Hg-capillary column. The detection limit and the recovery of the method were 0.002 and 84.2-98.5% (mean, 93.4%), respectively. The MeHg content in 492 abyssal fishes ranged from 0.037 to 2.009 mg/kg. The levels of MeHg [range, mg/kg (mean)] were significantly dependent on fish species and presented as the following; 0.157-2.009 (0.546) in Scalloped hammerhead shark, 0.211-0.878 (0.501) in Blue shark, 0.121-0.993 (0.482) in Spiny dogfish, 0.243-0.658 (0.397) in Salmon shark, 0.074-1.958 (0.353) in Blacktip shark, 0.038-0.807 (0.302) in Southern hake, 0.099-0.511 (0.300) in Scorpion fish, and 0.037-0.133 (0.067) in Ling. The monitoring results showed that the estimated weekly intake of MeHg from sharks, Southern hake, and Ling were lower than the provisional tolerable weekly intake recommended by the Joint FAO/WHO expert committee on food additives.

Comparison of Volatile Components in Organs of Ocimum basilicum L. cultivated in Korea (국내 재배 바질의 품종간 부위별 휘발성 성분 비교)

  • Ahn, Dai-Jin;Lee, Jae-Gon;Kim, Mi-Ju;Lee, Jong-Chul
    • Korean Journal of Medicinal Crop Science
    • /
    • v.9 no.2
    • /
    • pp.130-138
    • /
    • 2001
  • This study was conducted to compare volatile components from the ten kinds of basils cultivated in Korea. The ten kinds of basils were separated flower, leaf, and stem part from whole plants, respectively. All sample separated were extracted by simultaneous steam distillation-extraction method(SDE) and were analyzed by gas chromatography(GC) and mass selective detector(MSD). Total 42 components were identified in essential oils including 11 alcohols, 6 carbonyls, 20 hydrocarbons and 5 esters components. The major components were linalool, methyl chavicol, eugenol, trans-methyl cinnamate, ${\beta}-cubebene$ and 1,8-cineole. The content of linalool was high significantly in the flower$(31.8{\sim}53.0%)$, the leaf and stem showed $21.8{\sim}35.8%$ and $3.5{\sim}22.4%$, respectively. Especially, the content of methyl chavicol was high relatively in the leaf$(0.4{\sim}32.9%)$, the flower and stem showed $0.2{\sim}24.1%$ and $0{\sim}2.2%)$, respectively. Articock, figz, glove, and greek basils were rich in eugenol$(18.8{\sim}48.7%)$ and poor in methyl chavicol$(0{\sim}5.4%)$ when compared with others kinds of basils. The composition of the components identified showed quite difference between kinds of basils, and the number of components identified in stem was much less than that in flower and leaf

  • PDF

A Study on Migration of Ethylenediamine and Hexamethylenediamine from Polyamide Utensils (Polyamide 조리기구로부터 Ethylenediamine 및 Hexamethylenediamine의 이행에 관한 연구)

  • Eom, Mi-Ok;Kwak, In-Shin;Yoon, Hae-Jung;Jeon, Dae-Hoon;Choi, Hyun-Chul;Kim, Hyung-Il;Sung, Jun-Hyun;Park, Na-Young;Kim, So-Hee;Lee, Young-Ja
    • Journal of Food Hygiene and Safety
    • /
    • v.25 no.1
    • /
    • pp.36-42
    • /
    • 2010
  • The method for the determination of ethylenediamine (EDA) and hexamethylenediamine (HMDA) in food simulants was developed, and migration amounts of these compounds was monitored for 124 polyamide (PA) utensils. The diurethane derivatives of EDA and HMDA, which produced by reaction with ethyl chloroformate, were analyzed by using gas chromatograph (GC)/flame ionization detector (FID) and GC/mass spectrometer (MS). The developed method was validated with $0.3\;{\mu}g/mL$ of limit of detection (LOD) for EDA and $0.1\;{\mu}g/mL$ of LOD for HMDA, > 0.999 of linearity($r^2$) and > 88% of recovery. The EDA was detected 1.31 and $02.06\;{\mu}g/mL$ for 2 samples in water. The HMDA was detected $0.29\;-\;0.93\;{\mu}g/mL$ for 3 samples in 20% ethanol and $0.26\;-\;0.44\;{\mu}g/mL$ for 10 samples in n-heptane. These migration levels were below the specific migration limits (SML) of $12\;{\mu}g/mL$ and $2.4\;{\mu}g/mL$ for EDA and HMDA established in EU.

Study on the Analytical Method and Monitoring of the Oxidized Polyethylene Wax in Foods (식품 중 oxidized polyethylene wax 분석법 연구 및 함유량 실태 조사)

  • Choi, Seung-Hyun;Kim, Jae-Min;Choi, Sun-il;Jung, Tae-Dong;Cho, Bong-Yeon;Lee, Jin-Ha;Lee, Gunyoung;Lim, Ho Soo;Yun, Sang Soon;Lee, Ok-Hwan
    • Journal of Food Hygiene and Safety
    • /
    • v.32 no.4
    • /
    • pp.284-289
    • /
    • 2017
  • Oxidized polyethylene wax (OPEW) is, one of the food additives, used as a coating agent in citrus fruits and nuts. OPEW is authorized to quantum satis in EU, USA, and is acceptable less than 250 mg/kg in Australia and New Zealand. But OPEW is unauthorized as a food additive in Korea. This study was to establish the analytical method of OPEW and demonstrate the effective application of various food samples. We first conducted to compare the various analytical method including acid value (AV), high temperature gel permeation chromatography (HT-GPC), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS), gas chromatography flame ionization detector (GC-FID) and fourier transform infrared spectroscopy (FT-IR). This result indicated that FT-IR spectrum of OPEW treated food sample displayed absorption bands for carbonyl group (C=O, $1714cm^{-1}$), ester group (C-O, $1463cm^{-1}$), aliphatic group (C-H, $2916cm^{-1}$). Furthermore, IR spectrum of OPEW treated food sample showed similar tendency with IR spectrum of OPEW standard. Therefore, it is confirmed that analytical method using FT-IR can be detected on analysis of OPEW in food. As a result of monitoring of 111 samples using established analytical method, OPEW was not detected in the food samples.

Establishment of Pre-Harvest Residue Limit for Buprofezin and Penthiopyrad during Cultivation of Oriental melon (Cucumis melon var. makuwa) (참외(Cucumis melon var. makuwa)에 대한 Buprofezin 및 Penthiopyrad의 생산단계 잔류허용기준 설정)

  • Kim, Hea Na;Kim, Seong Beom;Choi, Eun;Woo, Min Ji;Kim, Ji Yoon;Saravanan, Manoharan;Hur, Jang Hyun
    • The Korean Journal of Pesticide Science
    • /
    • v.18 no.3
    • /
    • pp.123-129
    • /
    • 2014
  • The present work was aimed to determine the pre-harvest residue limits (PHRLs) and the safety management of commonly used pesticides namely buprofezin and penthiopyrad on oriental melon (Cucumis melon var. makuwa). In this study, the buprofezin (diluted two thousand fold) and penthiopyrad (diluted four thousand fold) were sprayed single time on oriental melon in the cultivation areas Sangju (site 1) and Sungju (site 2). Oriental melon were randomly collected from the both areas at the end of 0 (2 hours after pesticides spaying), 1, 2, 3, 5, 7, 9 and 10 days. For analysis, each samples were partitioned twice (80 and 70 mL) with dichloromethane and purified by florisil SPE cartridge. Finally, the residual amounts of both pesticides in all samples were analyzed using gas chromatography/nitrogen phosphorus detector (GC/NPD). In this study, the method limit of quantification (MLOQ) for both buprofezin and penthiopyrad in oriental melon was found to be $0.01mg\;kg^{-1}$ and their recovery levels were 91.1~98.6% and 90.0~104.6%, respectively. Further, the calculated biological half-life for buprofezin and penthiopyrad in oriental melon were 3.9 and 3.5, and 3.0 and 2.7 days in site 1 and 2, respectively. The results of this study found that the PHRLs for buprofezin and penthiopyrad were 4.24 and $2.31mg\;kg^{-1}$, respectively at 10 days before harvest. Consequently, the present study suggest that the residual amounts of both pesticides will be lower than the maximum residue limits (MRLs) when oriental melon is harvested.

A Study on Fat Content in Commercial Retort Foods - Crude Fat, Saturated Fatty Acid and Trans Fatty Acid - (시판 레토르트식품의 지방함량 조사 - 조지방, 포화지방, 트랜스지방산 중심으로 -)

  • Jeong, Da-Un;Im, June;Kim, Cheon-Hoe;Kim, Young-Kyoung;Park, Yoon-Jin;Om, Ae-Son
    • Korean journal of food and cookery science
    • /
    • v.31 no.5
    • /
    • pp.652-659
    • /
    • 2015
  • The aim of this study was to provide nutrition information to consumers by analyzing crude fat, saturated and trans fatty acids in commercial retort foods (n=70). The following sauce products of curries (n=21) and black-bean-sauces (n=16), other sauces (n=17) and instant cooking foods (n=16) were collected. Crude fat contents were quantified with the Rose-Gottlieb method using acid digestion. While saturated and trans fatty acids were examined by gas chromatography with a flame ionization detector (FID). Crude fat, saturated and trans fatty acid content ranges were $0.47{\pm}0.42{\sim}12.80{\pm}0.07g/100g$, $0.24{\pm}0.02{\sim}17.41{\pm}0.41g/100g$, $0.00{\pm}0.00{\sim}0.46{\pm}0.05g/100g$, respectively. Maximum recovery of analysis values was crude fat (119.7%), saturated fat (119%) and trans fatty acid (90%) compared the actual amounts based on the reference value indicated on the nutrition label. The analyzed samples were found to be compliant with nutrition label standard, because the contents of crude fat, saturated fatty acid, trans fatty acid were less than 120% of the reference value indicated on the nutrition label in retort foods. Therefore, the nutrition information on retort foods available to consumers was found to be trustworthy.