##burys Excerpt InDandelion Wind, By Ray Bradbury

Summer brings a sense of joy with its bright days. In Ray Bradburys excerpt from his novel Dandelion Wind. Bradbury utilizes rhetorical devices throughout the excerpt to provide a mysterious atmosphere to his novel. Throughout the beginning of the passage, the author uses an array of different rhetorical devices to give us a glimpse about Douglas Spauldings feelings towards the beginning of summer.Ray Bradbury utilizes personification in sentences 1 through 5. For example The town covered over with darkness...the wind had the proper touch, the breathing of the world was long and warm and slow. The author drives a clear picture of a mysterious atmosphere by the use of the word Darkness. By adding The wind had the proper touch.†¦show more content†¦He uses specific choice of words like Dark, Sorcerer and Visions to provide a sense of wonder and mystery as if it was an adventure. Which portrays the anticipation that Douglas feels towards all of the adventures that summer will b ring. The passage also consists of a simile in lines 48 through 50. The sentence reads The street lights, like candles on a black cake, went out. This particular lines connect to the first paragraph of the whole passage which mentioned the sun hasnt rised. The simile is a comparing lit street lights to that of candles which at first are lit but once you blow them out its light is gone. The lines are explaining that the street lights are off, now that they are not needed since the sun is out. Personification is found in lines 49 through 50. Which say the following As house lights winked slowly on. This sentence,personifies house lights as winking which represents house lights slowly turning on. Therefore, people are starting to wake up and the day is about to commence. Towards the end of the passage Douglas Spaulding is preparing to leave his home and enjoy his summer. A metaphor is illustrated in line 74 through 75. For example The town trolley would sail the rivering black streets . In the sentence, the streets are being compared to an ocean. Which portrays Douglas imagination and desire for his summer adventures to begin. Visual

The Nobel Prize in Chemistry Free Essays

In 2014, the Nobel Prize in Chemistry was awarded to Eric Betzig and William Moerner who, working separately, laid the foundation for SMLM. In essence, this method relies on the possibility to turn the fluorescence of individual molecules on and off. Scientists image the same area multiple times, allowing only a few interspersed molecules to glow each time. We will write a custom essay sample on The Nobel Prize in Chemistry or any similar topic only for you Order Now By superimposing these images, a dense super-image can be resolved at the nanolevel. With the development of this technique, Betzig and Moerner were able to overcome Abbe’s diffraction limit, allowing for the production of high resolution images that, before SMLM, had not been possible. Towards the end of the nineteenth century, Ernst Abbe and Lord Rayleigh formulated what is commonly known as the â€Å"diffraction limit† for microscopy. Roughly speaking, this limit states that it is impossible to resolve two elements of a structure that are closer to each other than about half the wavelength (?) in the lateral (x, y) plane and even further apart in the longitudinal (z) plane. Another consequence of the same diffraction limit is that it is not possible to focus a laser beam to a spot of smaller dimension than about ?/2. In the case of light (optical) microscopy, an important tool for the imaging of biological structures, this means that two objects within a distance between 400/2 = 200 nm (far blue) and 700/2 = 350 nm (far red) cannot be resolved. Although this is no real limitation for electron microscopy, in which the wavelength is orders of magnitude smaller, this method is very difficult to use on living cells. For instance, the length-scale of the E. coli cell is about 1,000 nm (1 ?m) which is larger than, but of similar magnitude, as the diffraction limit. This explains why, prior to the development of SMLM, it was difficult to image details of the internal structures of living bacteria. Perhaps this may be the reason why bacteria are considered to be â€Å"primitive† organisms with little internal structure. With single-molecule localization, more precise structures of bacteria and other small-scale entities, e.g. individual viruses, can be resolved.In SMLM, the photochemical properties of fluorescent proteins are exploited to induce a weakly emissive or non-emissive â€Å"dark† state. From the dark state, very small populations of fluorophores are returned to an emissive state by shining a weak light pulse that activates only a fraction of the fluorophores present. These fluorophores are excited and detected by glowing until they are bleached, at which point the procedure is repeated on a new subgroup of fluorophores. In order to be identified, however, the emission profile must exhibit minimal overlap in each image. The centroid position of each identified molecule is statistically fitted, often to a Gaussian function, and with a level of precision scaling with the number of detected photons. By imaging and fitting single emitters to a sub-diffraction limited area over thousands of single images, enough data is generated to create a composite reconstruction of all identified emitters. Single-molecule localization is a broad category consisting of specific techniques, such as STORM, PALM, and GSDIM, that operate using the conceptually similar procedure outlined above. The main difference between these types is the exact fluorophore chemistry used to turn the fluorescence of individual molecules on and off. The real breakthrough in single-molecule localization occurred in 2006, when Betzig and colleagues coupled fluorescent proteins to the membrane enveloping the lysosome, the cell’s recycling station. By activating only a fraction of the proteins at a time and superimposing the individual images, Betzig ended up with a super-resolution image of the lysosome membrane. Its resolution was far better than Abbe’s diffraction limit of 0.2 ?m, a barrier that previous microscopy techniques could not bypass. Since the ground-breaking discovery, SMLM has allowed organelles and single molecules to be resolved with an order of magnitude better resolution (with a localization accuracy of about 10 nm), in multiple color channels, and in 2D as well as 3D. Single-molecule microscopy allows quantification of the number of proteins within biological assemblies and characterization of protein spatial distribution, permitting the determination of protein stoichiometry and distribution in signaling complexes. For instance, for the ?2 adrenergic receptors, SMLM was used to show that the receptors are partially organized in mini-clusters only in cardiomyocytes but not in any other cell lines, and that these oligomers are not lipid raft related but rather depend on actin cytoskeleton integrity. Most importantly, the results of this study were different from those obtained from a similar report which used near-field scanning optical microscopy (NSOM), demonstrating the better precision of SMLM over other techniques. An additional important aspect of SMLM is that it can be used with other imaging techniques to elucidate receptor complex structures. In one study by Nan et al. (2013), the powerful sensitivity of FRET imaging to detect receptor proximity was combined with the capability of SMLM to obtain direct visualization of receptor oligomers in studying RAF, a strategic protein involved in RAS signaling. By means of cluster analysis, Nan and colleagues were able to show how RAF exists between an inactive monomeric state in the cytosol and a multimeric condition at the cell membrane when activated. The results from single-molecule localization confirmed the importance of dimer and oligomer formation in RAF signaling, even though the precise biological role of these different multimeric states is yet to be determined.The better definition of biological structures in the nanometer range as a result of SMLM has had most relevance in the field of neuroscience, where the morphology of neurons composed of dendritic spines and synapses is not suitable for confocal microscopy. For example, Dani et al. (2010) used single-molecule microscopy to image presynaptic and postsynaptic scaffolding proteins in the glomeruli of the mouse olfactory bulb to show distinct punctate patterns that were not resolved by conventional fluorescence imaging. Lastly, the high resolution of SMLM has enabled a deeper understanding of chromosome organization and genome mapping. Wang et al. (2011) determined the distribution of nucleoid-associated proteins in live E. coli cells, while Baday et al. (2012) were able to label 91 out of a total of 107 reference sites on a 180 kb human BAC gene with a 100 bp resolution. DNA mapping with such resolution offers the potential to uncover genetic variance and to facilitate medical diagnosis in genetic diseases. Nonetheless, there are a few challenges that come with single-molecule microscopy, namely errors in detection efficiency and localization uncertainty. Since using fluorescent proteins as labels involves the complications associated with protein expression, errors in this step (e.g. misfolding, incomplete maturation, etc.) can lead to the production of label molecules that are not fluorescent. This can directly affect counting studies, as the number of counted molecules can be underestimated. However, it is possible to use the obtained count (after correcting for blinking artifacts) for the counting. In one study that involved identification of protein complex stoichiometry by counting photobleaching steps, Renz et al. (2012) accounted for errors in detection efficiency using a binomial model, which was found to provide accurate results. Incorporating detection efficiency into a model for the ratio between monomers and dimers can also rectify efficiency errors. In terms of localization uncertainty, each photon from the emitter molecule provides a sample of the point spread function (PSF) from the molecule. Based on these samples, single molecule localization algorithms provide an estimate for the position of the fluorescent molecule. This estimate is prone to uncertainties, especially due to limited sampling (i.e. the limited number of photons obtained from the molecule). By ensuring that the imaged molecules within a frame are spatially separated enough so that the localization algorithms can correctly identify them, however, it is possible to minimize the effect of localization uncertainty on counting measures. Despite its potential shortcomings, single-molecule localization enables high resolution imaging on the scale of nanometers, which defies Abbe’s diffraction limit of 0.2 ?m. SMLM has been used to elucidate specific cell structures, as in Betzig’s visualization of the lysosome membrane, and receptor complexes, as in the case of RAF. The technique has also been used to refute results of similar studies that used different imaging protocols, as shown when determining the specific location of ?2 adrenergic receptors. Overall, SMLM has ushered in a new era of high resolution imaging that not only allows for accurate insight into individual cell and protein structure, but also enables identification of abnormalities in cellular processes that ultimately manifest as genetic diseases. How to cite The Nobel Prize in Chemistry, Papers

Anne Frank lived with her family in a pleasant hou Essay Example For Students

Anne Frank lived with her family in a pleasant hou Essay se. For Anne and her sister, Margot, their early childhood was a sucure place inhabited by loving parents, relatives and nurses. However, the Nazis had gained power in some parts of Germany. The Nazis wanted all Jews to be killed. Otto Frank, Annes father, did not hestitate to wait for the Nazis to come into full power. In 1933, the Franks left Frankfort. Mrs. Frank and the two girls joined her mother in Aachen, near the Belgian border. Otto Frank went to Holland and started a business in food products. In the spring of 1934, the Franks reunited and settled in Amsterdam. Anne Frank lived in Amsterdam happily, like she did in Frankfort. She attended Montessori School and had a host of friends. Her father, however, was still worried for in Germany the Nazis gained almost complete power. In 1940, the Germans envaded and conquered Holland. Annes life had changed by the Germans taking control. She could not go to her school, and was to attend the Jewish Lyceum. No Jews were allowed out on the streets at night. In 1941, the Germans had their first round-up of Jews in Amsterdam. 5 months later, the Germans summonded 16-year-old Margot Frank to report for deportation. Otto Frank, however, had contact with Dutch friends, and were able to hide out in the attic of a house. The morning after Margot was summonded they left Amsterdam and went to the attic of the house called the Secret Annexe. In the Secret Annexe they were joined by the Van Daan family. There was Mr. and Mrs. Van Daan and their son Peter. Later, a eldery dentist, Alburt Dussel, was invited to share their refuge. The 8 Jews hid in the Secert Annexe for many years. Otto Franks Dutch friends, brought them food and even gifts. The news in the fall of 1942 was terrifying for the Franks. The roundup of Jews from Holland was proceeding according to plan. While the Franks were in hiding, Germany was at the height of conquest. But of August 4, 1944, the Gestapo penetrated into the Frnaks hiding place. The 8 Jews, together were taken to Gestapo headquaters in Amsterdam. The Franks, Van Daans, and Mr. Dussel were sent to Westbork. Anne Frank, Diary of a Young Girl was actually the diary of Anne Frank. Anne Frank was a girl who lived with her family during the time of while the Nazis took power. Anne Frank only kept her diary while hiding from the Nazis. This diary told the story of horror that the Nazis carried out. Anne Frank hid from the Nazis for many years, writing what happened day by day in her life. Anne Frank was born on June 12, 1929, in the German city of Frankfort. She did not know what was happening at most times. Anne was not very intellegent, but her sister was an A student. Anne Frank had loving parents who supported her desisions. Otto Frank was a firm man who always believed that it was his job to look out for his family. He did anything to keep them safe. Otto was a respected business man. Sometimes he would get upset with Anne, but he always loved her. He was not strong, but tall. Otto loved his family. .