4,103 research outputs found

    Simultaneous heat and mass transfer to a liquid through two separated interfaces

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    The oxygenator is the main element of a heart-lung machine, which takes over the work of the lungs (adding oxygen to and removing carbon dioxide from the blood) during an operation. Oxygenators function by passing oxygen through a hollow fiber (straw-like fiber), where blood gases are exchanged via tiny pores in the fiber walls. In this study, a fiber-in-fiber technology was used to design a temperature controlled blood oxygenator membrane module. A Celgard® X-10 hollow fiber was put through the lumen of a polypropylene hollow fiber having a solid wall. Both fibers are made of polypropylene and are waterproof due to their hydrophobic properties. A heating fluid (e.g., deionized water) was circulated on the shell side of the outer set of the nonporous hollow fiber having a solid wall. In this way, the temperature level of the oxygenated deionized (DI) water was maintained at the desired temperature. The hollow fiber module carried out the removal of carbon dioxide and absorption of the oxygen under various conditions of temperature and flow rate. The hollow fiber module, which was used for this experimental work, was effective in removing carbon dioxide. High percentage removal of carbon dioxide was achieved at lower feed water flow rates while oxygen was absorbed into the water stream. The flow rate of the feed water and the temperature of the circulated water were important factors controlling the concentration of dissolved oxygen in water

    Ionic liquids as additives for biodegradable polyactic acid

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    In this study, two ionic liquids (IL) with different anions (decanoate, tetrafluoroborate) but with the same phosphonium based cation were evaluated as potential plasticizers and lubricants for polylactic acid (PLA) and also for their effects on its hydrolytic and thermal degradation. Both ILs at 5wt% were well dispersible and partly miscible with PLA as evidenced by scanning electron microscopy/energy dispersive x-ray scattering, SEMIEDX, and glass transition temperature, Tg, characterization, as well as from solubility parameters calculations. The effects of the IL containing a decanoate anion were more pronounced on lubrication and degradation as evidenced by reduced melt viscosities and accelerated thermal/hydrolytic degradation; this IL could also considered as a more effective plasticizer based on Tg suppression results although the degree of plasticization could also be affected by the observed excessive molecular weight, MW, degradation during melt processing. The IL containing the tetrafluoroborate anion increased the thermal stability of PLA as also confirmed from rate constants calculated from random chain scission statistics and activation energies from thermogravimetric analysis, and accelerated its hydrolytic degradation, but to a lesser extent than the decanoate based IL. The catalytic role of the decanoate anion in hydrolytic degradation was confirmed through experiments with a model compound. Hydrolytic chain scission of ester bonds catalyzed by acid groups are the suggested mechanisms of hydrolytic degradation based on results of pH and acid number changes, although it appears that the presence of the phosphonium cation contributes also to accelerated degradation. Degradation results were confirmed by optical and SEM examination and experiments in as received and sterilized soil. The different surface characteristics of PLA/ILs were reflected in differences in coefficients of friction and contact angles. The tetrafluoroborate anion containing IL reduced the flexural modulus and strength of PLA, affecting much less its ductility than the decanoate anion containing IL

    Sympathetic Renal Innervation and Resistant Hypertension

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    Hypertension in chronic renal disease and renovascular disease is often resistant to therapy. Understanding the pathogenic mechanisms responsible for hypertension in these conditions may lead to improved and more targeted therapeutic interventions. Several factors have been implicated in the pathogenesis of hypertension associated with renal disease and/or renal failure. Although the role of sodium retention, total body volume expansion, and hyperactivity of the renin-angiotensin-aldosterone system (RAAS) are well recognized, increasing evidence suggests that afferent impulses from the injured kidney may increase sympathetic nervous system activity in areas of the brain involved in noradrenergic regulation of blood pressure and contribute to the development and maintenance of hypertension associated with kidney disease. Recognition of this important pathogenic factor suggests that antiadrenergic drugs should be an essential component to the management of hypertension in patients with kidney disease, particularly those who are resistant to other modalities of therapy

    コクサイカ ジダイ ニオケル カンジン シュギロン ノ イデオロギーセイ

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    国際化の進展により日本人の対外国文化及び外国人との接触が急増すると、「(欧米人に対する) 日本人とは何か?」という疑問が再び起こりだした。これは国際化時代に適応される日本人のアイデンティティの樹立を促す刺激に働きかけた。これに当たるために日本的集団主義と名づけられた間人主義(contextualism)が主張された。だが間人主義論は、日本文化の独自性を強調し過ぎ、異文化(特に欧米文化)に対する「排他性」、人類文明の危機を克服するために優越な日本文化を世界へ拡散すべきだという「拡張性」を帯びるようになった。さらに、日本文化の独自性と優越性とを主張する根拠が非客観的であり、「作為性」をも呈している。このような三つの側面から間人主義論は旧本の国際化時代に似合うイデオロギー性を内包しているといえる。だが、今まで出ている日本文化論のイデオロギー性の研究には拡張性ついての言及はほとんど見えなく、大方、作為性と排他性とに焦点が合わされている。作為性と排他性という枠組みは、日本が国内的問題に眼を向けていた高度経済成長期における日本文化論のイデオロギー性に対する分析の枠組みとしては有効であったが、国際化時代における日本文化論の持つイデオロギー性を説明するのには十分ではないと思われる。日本において国際化時代の文化的意味が欧米近代文明の限界を強調し、その解決策として日本文化を国際化するところにあるといえば、日本文化の世界への拡散という拡張性を抜きにして、間人主義論のイデオロギー性を明らかにするのは不可能である。したがって、本文では作為性・排他性・拡張性という観点から国際化時代の間人主義論のもつイデオロギー性を分析した。In line with the increasing contacts of the Japanese people with the foreign cultures and people amid internationalization, there has again risen to the surface the question "Who are the Japanese (as compared to the Europeans)?" This question mark is a stimulus to setting up the identity of the Japanese adaptable to the age of internationalization. In answer to this demand, the contextualism generally known as a Japanese version of collectivism has been argued for. But an essay of the contextualism puts too much emphasis on the idiosyncrasy of Japanese culture and thus includes exclusiveness over other cultures, especially European culture, going so far as to argue for the expansion of superior Japanese culture so as to overcome the crisis of human civilization. In addition, the arguments for the idiosyncrasy and superiority are unscientific and artificial. In these respects, that is, exclusiveness, expansiveness, and artificiality, an essay of the contextualism takes on an ideological character corresponding to the age of Japanese internationalization. So far, however, most of the analyses on the ideological character of Japanese culture have focused on the artificiality and exclusiveness, but the ideological character of Japanese culture cannot be fully explained without bringing in the expansiveness of Japanese culture. Hence, this paper deals with the ideological character of an essay of the contextualism in the age of internationalization from the three points of the view, i. e. artificiality, exclusiveness and expansiveness

    Accuracy of Various Newer Pedometers Placed at Different Body Sites

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    Introduction: Pedometers are increasingly used as a self-monitoring aid for achieving and increasing daily physical activity. Older pedometers had varied levels of accuracy ranging from 0 to 45% difference and were needed to be positioned in a certain way (on the waist). Newer models can be placed anywhere on the body but its accuracy is unknown when they are placed at different bodily sites. Purpose: We determined the accuracy of various newer pedometers under controlled laboratory and free walking conditions. Method: A total of 40 subjects (20 male and 20 female) varying widely in age (18-61 years) and BMI (18-38 kg/m²) were studied. The pedometers, including Omron HJ-320BULK, Omron HJ-324U, Life Source XI-25, Fitbit Ultra, and Virgin Health Miles, were placed at waist, at chest, in a pocket, and on an armband. The number of steps recorded with the pedometers was compared against those counted with a hand tally counter while the subjects walked on the treadmill at 54, 80, 107, 134, and 161 m/min and on paved ground outside at a self-selected pace. Results: Overall, all pedometers displayed values that were within 9% of actual steps in all conditions when they were placed at waist, chest, and armband. However, when they were placed in a pocket, step counts deviated significantly from the hand counts by \u3e 11% in some models (Life Source, Fitbit, and Virgin Health) (PConclusions:All the pedometers examined were accurate when they were placed at waist, chest, and armband no matter what walking speed or what terrain they exercised. But some pedometers did not register accuracy when they were put in the pocket

    Confirmatory and Exploratory Factor Analysis for Validating the Phlegm Pattern Questionnaire for Healthy Subjects

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    Background. Phlegm pattern questionnaire (PPQ) was developed to evaluate and diagnose phlegm pattern in Korean Medicine and Traditional Chinese Medicine, but it was based on a dataset from patients who visited the hospital to consult with a clinician regarding their health without any strict exclusion or inclusion. In this study, we reinvestigated the construct validity of PPQ with a new dataset and confirmed the feasibility of applying it to a healthy population. Methods. 286 healthy subjects were finally included and their responses to PPQ were acquired. Confirmatory factor analysis (CFA) was conducted and the model fit was discussed. We extracted a new factor structure by exploratory factor analysis (EFA) and compared the two factor structures. Results. In CFA results, the model fit indices are acceptable (RMSEA = 0.074) or slightly less than the good fit values (CFI = 0.839, TLI = 0.860). Many average variances extracted were smaller than the correlation coefficients of the factors, which shows the somewhat insufficient discriminant validity. Conclusions. Through the results from CFA and EFA, this study shows clinically acceptable model fits and suggests the feasibility of applying PPQ to a healthy population with relatively good construct validity and internal consistency

    Effect of walking speed and placement position interactions in determining the accuracy of various newer pedometers

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    AbstractOlder types of pedometers had varied levels of accuracy, which ranged from 0% to 45%. In addition, to obtain accurate results, it was also necessary to position them in a certain way. By contrast, newer models can be placed anywhere on the body; however, their accuracy is unknown when they are placed at different body sites. We determined the accuracy of various newer pedometers under controlled laboratory and free walking conditions. A total of 40 participants, who varied widely in age and body mass index, were recruited for the study. The numbers of steps recorded using five different pedometers placed at the waist, the chest, in a pocket, and on an armband were compared against those counted with a hand tally counter. With the exception of one, all the pedometers were accurate at moderate walking speeds, irrespective of their placement on the body. However, the accuracy tended to decrease at slower and faster walking speeds, especially when the pedometers were worn in the pockets or kept in the purse (p < 0.05). In conclusion, most pedometers examined were accurate when they were placed at the waist, chest, and armband irrespective of the walking speed or terrain. However, some pedometers had reduced accuracy when they were kept in a pocket or placed in a purse, especially at a slower and faster walking speeds
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