The Role of Perfusion Computed Tomography in the Prediction of Cerebral Hyperperfusion Syndrome

Hyperperfusion syndrome (HPS) following carotid angioplasty with stenting (CAS) is associated with significant morbidity and mortality. At present, there are no reliable parameters to predict HPS. The aim of this study was to clarify whether perfusion computed tomography (CT) is a feasible and reliable tool in predicting HPS after CAS.We performed a retrospective case-control study of 54 patients (11 HPS patients and 43 non-HPS) with unilateral severe stenosis of the carotid artery who underwent CAS. We compared the prevalence of vascular risk factors and perfusion CT parameters including regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and time to peak (TTP) within seven days prior to CAS. Demographic information, risk factors for atherosclerosis, and perfusion CT parameters were evaluated by multivariable logistic regression analysis. The rCBV index was calculated as [(ipsilateral rCBV - contralateral rCBV)/contralateral rCBV], and indices of rCBF and TTP were similarly calculated. We found that eleven patients had HPS, including five with intracranial hemorrhages (ICHs) of whom three died. After a comparison with non-HPS control subjects, independent predictors of HPS included the severity of ipsilateral carotid artery stenosis, 3-hour mean systolic blood pressure (3 h SBP) after CAS, pre-stenting rCBV index >0.15 and TTP index >0.22.The combination of severe ipsilateral carotid stenosis, 3 h SBP after CAS, rCBV index and TTP index provides a potential screening tool for predicting HPS in patients with unilateral carotid stenosis receiving CAS. In addition, adequate management of post-stenting blood pressure is the most important treatable factor in preventing HPS in these high risk patients

Experimental study on the dye-sensitized solar cells using TiO2 nanoparticles

本研究為二氧化鈦(TiO2)在染料敏化太陽能電池(dye-sensitized solar cells, DSSCs)上之應用，利用預混式燃燒器火焰，添加鈦系化合物C12H28O4Ti(TTIP)，並以氣相燃燒合成奈米級TiO2顆粒，討論其晶相純度及粒徑大小，當O2/N2=30/70、Φ=1.0、TTIP=0.89%，時，粉末粒徑約為50nm，Anatase晶相含量為67%，由於改變收集方式，因此此數據與本實驗室先前所製作之Anatase晶相含量為97.7%相比較差，將本實驗製作之顆粒應用在染料敏化太陽能電池上可得到最佳光電轉換效率1.17%。SSCs之製備主要探討電池之工作電極之TiO2薄膜厚度、兩電極間距離以及電解液調配方式等數個研究方向。工作電極方面以刮刀成膜法(doctor blade method)製做，討論TiO2膜厚度，結果發現使用4克的P25 TiO2粉末加上15毫升去離子水，0.5毫升乙醯丙酮與0.5毫升界面活性劑(X-100)，塗佈三層TiO¬2薄膜厚度之DSSCs效率最佳；兩電極間厚度以100μm為最佳；在電解液的選用上，使用濃度為0.5M-0.05M 之LiI-I2，溶劑為體積比Propylene carbonate：Acetonitrile為9：1之電解液，再加入濃度為0.5M之 4-tert-butylpyridine(TBP)，最佳光電轉換效率可達2.115%。Flame synthesis of nanosized titanium oxide particles with the precursor titanium isopropoxide (TTIP) were used in dye-sensitized solar cells (DSSCs). In this study, particles collected in the premixed flames were studied for their morphology, crystal phase purity, and size. Results from X-ray diffraction (XRD) analyses show that TiO2 crystal phase purity and the size of TiO2 nanoparticles may be effectively controlled by the oxygen concentration and equivalence ratio(Φ). As a result, the anatase purity and the size of TiO2 particle can be 67% and 50nm. TiO2 nanoparticles are formed under the conditions of O2/N2=30/70,Φ=1.0, and TTIP=0.89%. Because of the different collected mothod, this particle anatase purity is lower than 97.7% that collected before. However, DSSCs are developed by using a dye-sensitized nanocrystalline TiO2 film display the photo-energy efficiency of 1.17%.DSSC is an alternative method for the development of a new generation of photovoltaic devices. DSSC is a combination of several materials, consisting of a transparent electrode coated with a dye-sensitized mesoporous film of nanocrystalline particles of TiO2, an electrolyte containing a suitable redox-couple and a platinum coated counter-electrode. Ruthenium 535-bis TBA (N719) is used as the dyesensitizers. The photo-energy conversion efficiency of DSSCs depends on the properties of its components. The photo-energy conversion efficiency of DSSCs can be optimized up to 2.115%, when the anode electrode made by doctor blade method with three layers. Furthermore, the spacer thickness is 100μm, and the electrolyte condition become [LiI]-[ I2] is 0.5M-0.05M in volume ratio Propylene Carbonate(PC)：Acetonitrile is 9：1 with 0.5M 4-tert-butylpyridine(TBP).第一章 緒論1.1 前言 1.2 研究背景2.3 太陽能電池3.3.1 單晶矽4.3.2 多晶矽5.3.3 非晶矽5.3.4 化合物半導體II-VI 族(CdS, CdTe, CuInSe2)5.3.5 化合物半導體III-V 族(GaAs, InP, InGaP) 6.3.6 染料敏化太陽能電池6.3.7 塑膠太陽能電池6.3.8 奈米碳管太陽能電池7.4 奈米顆粒7.5 研究動機與目的9二章 TiO2文獻回顧與理論基礎12.1 TiO2基本介紹 12.1.1 Anatase/Rutile 晶相之介紹12.1.2 光觸媒Photocatalyst13.2 奈米微粒的製備14.2.1 奈米微粒子的物理製備方法15.2.2 奈米微粒子的化學製備方法15.3 文獻回顧17三章 DSSCs文獻回顧與理論基礎24.1 DSSCs發展24.2 DSSCs構造24.3 DSSCs光電轉換原理29.4 光電轉換特性 30.5 DSSCs文獻回顧 31四章 奈米微粒子實驗研究與方法35.1 實驗基本架構與參數定義 35.1.1 實驗基本架構35.1.2 實驗參數定義35.2 TTIP介紹36.3 實驗設備36.3.1 燃燒器系統 36.3.2 氣體流量與燃料輸送系統37.3.3 其他設備37.4 實驗步驟38.4.1 實驗前準備 38.4.2 流量計與熱電偶之校正 39.4.3 實驗操作條件41.4.4 火焰之定量量測及定性觀察41.4.5 燃燒產物的收集與分析 42五章 DSSCs實驗研究與方法 45.1 材料準備45.2 實驗設備46.3 敏化太陽能電池各部之製備46.3.1 工作電極製備46.3.2 對電極製備47.3.3 敏化染料的配製48.3.4 電解液的配置48.4 DSSCs組裝與測試48六章 結果與討論 50.1 燃燒法粉末分析50.1.1 火焰的量測與觀察50.1.2 產物晶相分析結果51.1.3 產物粒徑之分析53.1.4 燃燒合成TiO2粉末於敏化太陽能電池之應用 54.2 改變DSSCs之變因討論55.2.1 薄膜厚度對DSSCs所產生的影響55.2.2 兩電極間距離對DSSCs之影響57.2.3 不同電解液對於DSSCs之影響57七章 結論與建議 60.1 結論 60.2 建議 61考文獻 63表72圖7

Association between Ambient Air Pollution and Emergency Room Visits for Pediatric Respiratory Diseases: The Impact of COVID-19 Pandemic

The level and composition of air pollution have changed during the coronavirus disease 2019 (COVID-19) pandemic. However, the association between air pollution and pediatric respiratory disease emergency department (ED) visits during the COVID-19 pandemic remains unclear. The study was retrospectively conducted between 2017 and 2020 in Kaohsiung, Taiwan, from 1 January 2020 to 1 May 2020, defined as the period of the COVID-19 pandemic, and 1 January 2017 to 31 May 2019, defined as the pre-COVID-19 pandemic period. We enrolled patients under 17 years old who visited the ED in a medical center and were diagnosed with respiratory diseases such as pneumonia, asthma, bronchitis, and acute pharyngitis. Measurements of particulate matter (PM) with aerodynamic diameters of 10) and 2.5), nitrogen dioxide (NO2), and Ozone (O3) were collected. During the COVID-19 pandemic, an increase in the interquartile range of PM2.5, PM10, and NO2 levels was associated with increases of 72.5% (95% confidence interval [CI], 50.5–97.7%), 98.0% (95% CI, 70.7–129.6%), and 54.7% (95% CI, 38.7–72.6%), respectively, in the risk of pediatric respiratory disease ED visits on lag 1, which were greater than those in the pre-COVID-19 pandemic period. After adjusting for temperature and humidity, the risk of pediatric respiratory diseases after exposure to PM2.5 (inter p = 0.001) and PM10 (inter p 2.5, PM10, and NO2 may play important roles in pediatric respiratory events in Kaohsiung, Taiwan. Compared with the pre-COVID-19 pandemic period, the levels of PM2.5 and PM10 were lower; however, the levels were related to a greater increase in ED during the COVID-19 pandemic

Profiles of Peripheral Immune Cells of Uncomplicated COVID-19 Cases with Distinct Viral RNA Shedding Periods

The heterogeneity of immune response to COVID-19 has been reported to correlate with disease severity and prognosis. While so, how the immune response progress along the period of viral RNA-shedding (VRS), which determines the infectiousness of disease, is yet to be elucidated. We aim to exhaustively evaluate the peripheral immune cells to expose the interplay of the immune system in uncomplicated COVID-19 cases with different VRS periods and dynamic changes of the immune cell profile in the prolonged cases. We prospectively recruited four uncomplicated COVID-19 patients and four healthy controls (HCs) and evaluated the immune cell profile throughout the disease course. Peripheral blood mononuclear cells (PBMCs) were collected and submitted to a multi-panel flowcytometric assay. CD19+-B cells were upregulated, while CD4, CD8, and NK cells were downregulated in prolonged VRS patients. Additionally, the pro-inflammatory-Th1 population showed downregulation, followed by improvement along the disease course, while the immunoregulatory cells showed upregulation with subsequent decline. COVID-19 patients with longer VRS expressed an immune profile comparable to those with severe disease, although they remained clinically stable. Further studies of immune signature in a larger cohort are warranted