Aseptic Techniques & Cell Counting Essay Example | Topics and Well Written Essays - 2500 words

Aseptic Techniques & Cell Counting - Essay Example flame loops, put slides in jars of Lysol or Chloros, put pipettes in their proper receptacles, and discard cultures into their appropriate autoclave buckets. Several different methods are used for sterilization and some of which we will use today. The maintenance of sterility requires the use of Aseptic Technique. The object of this is to prevent any form of contact between the sterile growth medium (e.g. petri dish containing nutrient agar) or the pure culture and any source of contaminating organisms. The new student should be aware that it is very easy to sterilize a pipette or bacteriological loop and then to place it on the non-sterile bench whilst picking up something else. Sources of contamination include: Any non-sterile surface, liquids, or air. Air is a very important contamination source because of; free-floating fungal or bacterial spores, liquid droplets, dust particles, dried skin scales, all of which may contain bacteria and/or fungi. Good aseptic technique is crucial for work in microbiology, microbial genetics, or biotechnology. Flaming using a Bunsen Burner is the classic method for rapid sterilization of bacteriological loops, glass pipette and bottle or flask necks. Flaming needs to be done for several seconds, long enough to raise the temperature well above 100 oC. Bottle necks should be rotated in the flame for 5 sec. or so to achieve this. For all basic techniques in microbiology and for today’s exercise in liquid transfer and inoculation, manual dexterity in removing screw-on lids is important. The most reliable technique is to use the little finger to unscrew and hold lids and plugs, leaving the other fingers free to hold loops or pipettes etc. The operator (i.e. you!) is the most likely source of small particles floating in the air and landing on your work. Breathing, coughing, sneezing and talking may all lead to some production of air-borne particles (aerosols) but more importantly respiratory secretions and saliva

California Racial Stereotypes Essay Example | Topics and Well Written Essays - 1000 words

California Racial Stereotypes - Essay Example He believes this is an important topic to pull up and write about as it is increasingly emerging in the modern world of sociology and culture. The author picks up a very smooth pace to start his topic as he describes the thoughts and writings of some literary writers about the racism and how it has emerged in the societies. His approach makes his writing an interesting piece of work to start with and understands the exact issue. However, he generalizes his point to the facts that racism of all kinds represents the same feelings of the groups against another group. He represents his views followed by a number of references to generalize the concept of racism in the societies, after which he focuses on his point of view on which he based his article. The author also explains how he believes racism to become a problem when it starts to exist within the groups, and starts to cause troubles between those groups or the individuals themselves. His keen concepts about racism and the links th at he created within the issues give this article a boost that would make it an immense influence on the readers that can relate. The author has used the theories relating to the racism against the blacks and the Chinese, and created a certain sense of interaction between them that has engaged the reader in his views. The author questions on how the attitudes of anti-blacks remains persistent in comparison to the attitudes of the anti-Chinese. The author presents his research on the views of how people can tend to change their attitudes towards one racist group and keep their attitudes static towards the other racist group. Thus, the author keeps his questions beyond his beliefs that all types of racisms are not identical and they are judged by their historical perspectives. The author has characterized the different types of attitudes that are associated with the Chinese and blacks racial categories. The analysis of the author describes many points of views that include the politic al, social, literary, and the nationalistic sources that have impacted the racism in the nineteenth and twentieth century. However, the best part about this piece of writing is that it isn’t a biased opinion. The author also includes many other sources from his study which include the stories form the racial neutralists. It represents the other views about the psychological characteristics that group people into certain clusters according to their skin colour, head-shape etc. The author describes how the recent studies about racism have only influenced upon the cultural and biological components as though they are inseparable. The author does not get his answer through these ideas. However, the author writes about the change in attitudes of the white Californians towards the blacks and the Chinese during the nineteenth century according to the theories of cultural and biological components but gets no further conclusion. Thus, he gives weight to the questions relating to the historical implications of the different attitudes. With a description of the history of Californian conflicts and racial problems, the author represents many of the viewpoints that he has collected. He performs research over many of the evidence showing the historic status of the blacks, nature and popularity of these groups and many other supporting historic events. The link to the historic events has made the argument stronger and much more precise through which