46 research outputs found
Bereiding van carboxymethylcellulose (C.M.C.)
No full textDocument(en) uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science
Bereiding van carboxymethylcellulose (C.M.C.)
No full textDocument(en) uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science
Montjuïc, her-bergt de stad
No full textGraduation project on rethinking the position of the mountain Montjuïc in Barcelona. Project rethinks what the mountain means to Barcelona as a citypark and how to reemphasize this. And develops a plan for reconnecting the entrance to the Montjuïc from the city centre and harbour front. With the development of a hotel, the Parador + as a meeting point and public space on the Montjuïc.Architecture, UrbanismArchitectur
[[alternative]]Synthesis and Applications of Cholesteric- Liquid Crystals and
No full text[[abstract]] 本研究合成含冠狀醚支鏈的冠狀醚－膽石醇液晶。此冠狀醚液晶不僅
具液晶性質，且仍保有冠狀醚在離子輸送上之功能及選擇性。 為使此
系統更切合生物體細胞膜內之離子傳輸，將此高溫型冠狀醚－膽石醇液晶
，與另一膽石醇液晶依不同比例混合，形成混合液晶，並加入不同的金屬
鹽類，尋找一安定的室溫型液晶。本研究使用電腦膜擬系統(InsightII
2.2 & Discover 3.1)分別繪出分子架構及對分子做動力學計算，以說明
混合液晶之生成與否及液晶相轉移溫度範圍之變化。實驗結果試圖找出混
合液晶之理論依據，並藉此預測混合液晶之生成與液晶溫度範圍變化之趨
勢。期盼可由這套電腦模擬系統提供尋找適用之混合液晶的一些訊息。
此種膽石醇－冠狀醚衍生物，具有明顯的疏水基(Chol -esteryl
Group) 及親水基(Crown Ether Group)，比一般冠狀醚更符合界面活性劑
之分子架構，以苯駢菲(Pyrene)螢光光譜及表面張力儀偵測其臨界微胞生
成濃度(Critical Micellar Concentration, C.M.C)，並探討微胞形成條
件。
moiety such as cholesteryl Benzo-15-Crown-5 (B15C5- COOCh) has
been synthesized.The crown ether chol- esteric-liquid crystal
also has the property of ion tr- ansport carrier.In order to
look for room temperatu- re liquid crystal,the crown ether-
cholesteric derivat- ive (B15C5COOCh) was mixed with other
cholesteric liquid crystals with different molar ratios and
some inorganic salts were added to the mixtures. Comphrehensive
graphic molecular modeling pro- grams (Insight II 2.2 and
Discover 3.1) were empl- oyed to draw the molecular mechanism
and caculate molecular energy of mixed liquid crystal.This
study was expected to understand the formation of mixed liquid
crystal and the variation of liquid crystal ph- ase transtion
temperature range. The cholesteryl Benzo-15-Crown-5 was
exhibit- ed to have distintive characteristics of a surfactant.
Fluorescene pyrene probe ,as sensitive tool,was ap- plied to
detect the C.M.C. of cholesteryl Benzo-15- crown-5 by the
Spectrofluorometer and surface tens- ion meter.
moiety such as cholesteryl Benzo-15-Crown-5 (B15C5- COOCh) has
Stealth-Trading: Which Traders' Trades Move Stock Prices?
No full textUsing audit trail data for a sample of NYSE firms, we show that medium size trades are associated with a disproportionately large cumulative stock price change relative to their proportion of all trades and volume. This result is consistent with the predictions of the stealth- trading hypothesis (Barclay and Warner (1993)). We find that the source of this disproportionately large cumulative price impact of medium size trades is trades initiated by institutions. This result appears robust to various sensitivity checks. Our findings appear to confirm street lore that institutions are informed traders.stealth-trading, adverse selection, informed trading, trade size
Empirical Studies of Market Microstructure.
No full textIn efficient markets, security prices move in response to the release of new information. Since transactions contain information, trading itself causes traders and market makers to update their beliefs and prices to be revised. The main part of this thesis (Chapters 2, 3, and 4) is devoted to the empirical investigation of how stock prices are updated in response to (large) trades, using tick-by-tick data distributed by the New York Stock Exchange. We show that market activity and trading volume are important determinants of the impact of trades on prices. Moreover, we show that there are large differences in price impact and price dynamics between frequently and infrequently traded stocks. In the final chapter of this dissertation (Chapter 5) we examine empirically the existence of comovements in the trading intensities of stocks of US department-store operators. We find significant comovements in the trading intensities of the stocks in this type of industry, which we explain by distinguishing idiosyncratic stock-specific news that applies to one stock only and sector-specific news that is potentially relevant for stocks in the same type of industry.
Pharmacodynamics of nitrofurantoin at different pH levels against pathogens involved in urinary tract infections
No full textBackground: Urinary tract infections are among the most common human infections. Due to the progressive increase in ESBL-producing bacteria and the unavailability of new antibiotics, re-evaluation of 'old' antibiotics is needed. However, the pharmacodynamics of nitrofurantoin under variable pH conditions are poorly understood. We determined the pharmacodynamic properties of nitrofurantoin at different pH levels using time-kill assays. Methods: Time-kill assays were performed at four pH levels (5.5, 6.5, 7.5 and 8.5), exposing the bacteria to 2-fold increasing concentrations from 0.125 to 32 times the MIC. Seven ESBL-positive and two ESBL-negative strains (MICs 8-32 mg/L) were used. The Δlog10 cfu/mL values at 6 and 24 h were plotted against each log10- transformed concentration and analysed with non-linear regression analysis using the sigmoid maximumeffect model with variable slope. Geometric means normalized by the MIC of the EC50, stasis and 1 and 3 log10 cfu/mL kill were calculated. Results: Minimum bactericidal effects differed significantly by species and pH level. At pH 5.5-6.5 bactericidal effects were observed at≥0.5×MIC for Escherichia coli and Enterobacter cloacae. At pH 8.5 only the two highest concentrations were considered bactericidal. Strong pH-dependent pharmacodynamic output parameters were observed in 6 h and especially 24 h modelling. At 24 h, pH 5.5-6.5 for E. coli and Klebsiella pneumoniae required significantly lower nitrofurantoin concentrations compared with pH 7.5 or 8.5. Although for E. cloacae similar strong decreasing trends were visible with decreasing pH, none of the tested pharmacodynamic parameters was significant. Conclusions: Nitrofurantoin bactericidal activity against Enterobacteriaceae significantly increases at lower pH levels. Bactericidal activity of nitrofurantoin may be overestimated or underestimated, which may have implications for therapy and the interpretation of clinical breakpoints. © The Author 2017
Tailoring silk fibroin separator membranes pore size for improving performance of lithium ion batteries
No full textThe search of natural materials for their application in energy storage systems in general and batteries in particular is growing due to their promising properties and the need of environmental sustainability. Silk fibroin (SF) is one of those materials due to their mechanical and thermal properties, non-toxicity and biocompatibility. Further, SF exhibits excellent cycling performance as separator for lithium-ion battery applications. This work reports on SF membranes with different pore sizes (within the rages: 38–22, 106–38 and 250-106 μm) prepared for separators in lithium-ion batteries. The morphology, structure and thermal properties were evaluated. It is shown that the β-sheet conformation percentage increases with increasing pore size, which also leads to higher electrolyte uptake, reaching 350% for SF membranes with pore size of 250–106 μm. With respect to battery performance, a high discharge capacity (131.3 mAh g−1, for C/8) is obtained for this membraneFCT (Fundação para a Ciência e Tecnologia) for financial support under the framework of Strategic Funding grants UID/FIS/04650/2019, and UID/QUI/0686/2019 and project PTDC/FIS-MAC/28157/2017. The author also thanks the FCT for financial support under grant SFRH/BPD/112547/2015 (C.M.C.) and Investigator FCT Contract CEECIND/00833/2017 (R.G.). Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through project MAT2016-76039-C4-3-R (AEI/FEDER, UE) (including FEDER financial support) and from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06
Electroactive poly(vinylidene fluoride) based materials: recent progress, challenges and opportunities
No full textA poly(vinylidene fluoride) (PVDF) and its copolymers are polymers that, in specific crystalline phases, show high dielectric and piezoelectric values, excellent mechanical behavior and good thermal and chemical stability, suitable for many applications from the biomedical area to energy devices. This chapter introduces the main properties, processability and polymorphism of PVDF. Further, the recent advances in the applications based on those materials are presented and discussed. Thus, it shown the key role of PVDF and its copolymers as smart and multifunctional material, expanding the limits of polymer-based technologies.FCT (Fundação para a Ciência e Tecnologia) for financial support
under the framework of Strategic Funding grants UID/FIS/04650/2019, and UID/QUI/0686/2019 and project PTDC/FIS-MAC/28157/2017, PTDC/BTMMAT/28237/2017, PTDC/EMD-EMD/28159/2017. The author also thanks the FCT for financial support under grant SFRH/BPD/112547/2015 (C.M.C.), SFRH/BPD/98109/2013 (V.F.C.), SFRH/BD/140698/2018 (R.B.P.), SFRH/BPD/96227/2013 (P.M.), SFRH/BPD/121526/2016 (D.M.C.), SFRH/BPD/97739/2013 (V. C.), SFRH/BPD/90870/2012 (C.R.). Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through project MAT2016-76039-C4-3-R (AEI/FEDER, UE) (including FEDER financial support) and from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06)
Silk fibroin as sustainable advanced material: material properties and characteristics, processing, and applications
No full textBio-based resources are proposed as next-generation materials for advanced application.
Among them, silk fibroin, a protein-based material generally obtained from Bombyx mori
cocoons, is considered to play an increasing role in the development of a more sustainable
generation of devices. In this review, the silk fibroin molecular structure and its original
properties are presented, together with a wide overview of the available modifications
and processing methods to reach custom structural and functional variations.The authors thank the FCT (Fundação para a Ciência e Tecnologia) for financial support
under the framework of Strategic Funding grants UID/FIS/04650/2019, and
UID/EEA/04436/2019; and project PTDC/FIS-MAC/28157/2017. The author also thanks
the FCT for investigator FCT contract 2020.04028.CEECIND (C.M.C.) as well as by the
POCH and European Union. The authors thank funding by the Spanish State Research
Agency (AEI) and the European Regional Development Fund (ERFD) through the project
PID2019-106099RB-C43 / AEI / 10.13039/501100011033 and from the Basque Government Industry and Education Departments under the ELKARTEK program,
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