Traditional way of synthesizing sensitive rhodamine starts with rhodamine B‚ amino compound‚ and some alkali additive in the presence of weak base. However‚ for RH-PY‚ the stearic hindrance of pyrene slows the reactivity‚ and the reaction does not go to completion. Therefore‚ the reaction procedure was modified as follows. First‚ HATU and DIPEA were used to activate the carboxyl group of rhodamine B‚ then the activated rhodamine B was reacted with 1-aminopyrene. By introducing this method‚ the reaction
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N08/4/BIOLO/SPM/ENG/TZ0/XX+ 88086004 Biology Standard level PaPer 1 Monday 17 November 2008 (afternoon) 45 minutes INSTRUCTIONS TO CANDIDATES • • • Do not open this examination paper until instructed to do so. Answer all the questions. For each question‚ choose the answer you consider to be the best and indicate your choice on the answer sheet provided. 8808-6004 13 pages © International Baccalaureate Organization 2008 –– 1. Which of the following characterizes tissues? A. B
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is the subject of many studies and investigations‚ such as William C. Dement and Christopher Vaughan’s paper‚ “Sleep Debt and the Mortgaged Mind‚” June J. Pilcher and Amy S. Walters’ article‚ “How Sleep Debt Hurts College Students‚” and Matthew Ashton’s‚ “A Greater College Debt.” Sleep debt is a massive problem; this idea is easily introduced in William C. Dement and Christopher Vaughan’s paper‚ “Sleep Debt and the Mortgaged Mind‚” with the explanation of the true cause of the Valdez incident‚ a
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Introduction: The purpose of this lab was to learn how to use salicylic acid to make aspirin. Aspirin is the most widely used over-the-counter drug in the world. The average tablet contains about 325 milligrams of acetylsalicylic acid with an inert binding material such as starch. Aspirin is used to relieve pain‚ reduce inflammation‚ and lower fever. Aspirin originally was derived by boiling the bark of the white willow tree. Although the salicin in willow bark has analgesic properties‚ purified
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In biology and ecology‚ extinction is the end of an organism or of a group of organisms (taxon)‚ normally a species. The moment of extinction is generally considered to be the death of the last individual of the species‚ although the capacity to breed and recover may have been lost before this point. Because a species’ potential range may be very large‚ determining this moment is difficult‚ and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa‚ where a species
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What is the aim of the study? [1 mark] The aim of this study is to modify knowledge of genes and enzymes for carotenoid biosynthesis in plant and also put some light on the challenges that are currently being faced by plant developmental biology and biotechnology. What is the author’s hypothesis? Was it supported or refuted by their research? [2 marks] The author’s hypothesis was that‚ “ Carotenoids protect photosynthetic organisms against potentially harmful photooxidative processes
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experiment‚ the hood in the lab was used. The curds were placed in a 100 mL beaker and extracted using 30 mL of ethyl acetate. The curds were crushed with a stirring rod. This extraction was then gravity filtered through a funnel fitted with the filter paper. A rubber policeman was used to scrape the beaker to get as much casein as possible. This casein was then put aside in the hood safely. Boiling chips were put into an Erlenmeyer flask along with the filtrate collected. This flask was then put inside
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On the power of man: A position paper on synthetic biology BBC Horizon’s documentary “Playing God” has given its viewers a glimpse on the technological advances of the field Synthetic Biology‚ a field that dwells on the so-called artificial life. Like what almost all the field of science has been brought about‚ synthetic biology’s aim is to be of benefit to the human kind—to serve our dominant race for scientific and economic prosperity. In itself‚ however‚ ethical issues are bugging this
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Biological Science‚ 4e (Freeman) Chapter 1 Biology and the Tree of Life 1) Which of the following statements about cells is true? A cell is _____. A) only found in multiples of two‚ because single cells cannot exist independently B) always between 200 and 500 micrometers in diameter C) characteristic of eukaryotic but not prokaryotic organisms D) characteristic of both prokaryotic and eukaryotic organisms Answer: D Reference: Section 1.4 Bloom’s Taxonomy: Level 1 Knowledge 2)
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ACCOUNTING 505 SYNTHESIS |Key Features of a Synthesis | (1) It accurately reports information from the sources using different phrases and sentences; (2) It is organized in such a way that readers can immediately see where the information from the sources overlap;. (3) It makes sense of the sources and helps the reader understand them in greater depth. |The Background
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