主题：英文论文写作－Abstract篇

An abstract, or summary, is published together with a research article, giving the reader a "preview" of what's to come. Such abstracts may also be published separately in bibliographical sources, such as Biological Abstracts and Chemical Abstracts. They allow other scientists to quickly scan the large scientific literature, and judge whether it would serve his or her purposes to read the entire paper in depth. The abstract should be a little less technical than the article itself; you don't want to dissuade your potential audience from reading your paper. Although it is not always easy to write an excellent abstract, it can be done with practice. Anyway, it is easier to effectively and concisely summarize a paper after the Results and Discussion section are completed.

Basically, an abstract is a one-paragraph synopsis of your entire paper. The abstract is placed at the beginning of the second page of the paper, after the title page. Although Abstract is the first section of one paper, the Abstract should not be written until the rest of the paper is done because it is a brief summary of everything else. It should be understandable by itself, and briefly tell your reader the main messages in paper. A well-prepared abstract should enable the reader to identify the basic content of a document quickly and accurately, to determine its relevance to their interests.
The abstract, together with the title, must be self-contained as it is published separately from the paper in abstracting services such as Biological Abstracts or Current Contents. Omit all references to the literature and to tables or figures, and omit obscure abbreviations and acronyms even though they may be defined in main body of the paper. The abstract should mainly state the principal objectives and scope of the investigation where these are not obvious from the title. Start by writing a summary that includes whatever you think is important, and then gradually prune it down to size by removing unnecessary words, while still retaining the necessary concepts.

More importantly, it should summarize the question being investigated or main purpose in the paper, the methods used in the experiment, the major results and author’s principal conclusions. Condense the whole paper into miniature form plus the key points. No new information, no supporting material, limited details, just the essential message that explains what you did and found out. Do not include details of the methods employed unless the study is methodological, i.e. primarily concerned with methods. The abstract must be concise, not exceeding 250 words. If you can convey the essential details of the paper in 100 words, do not use 200. Present the important findings, including values and methods that are crucial to understanding and interpreting the findings. The reader should be able to determine the major topics in the paper without reading the entire paper.
For example: Aspergillus nidulans grows by apical extension of multinucleate cells called hyphae which are subdivided by the insertion of crosswalls called septa... This requires coordination between localized growth, nuclear division, and septation. I searched a temperature-sensitive mutant collection for strains with conditional defects in growth patterning. I identified six mutants...which I call hyp for hypercellular. Phenotypic analyses...of hyp mutants... suggest a mechanism for coordinating apical growth, subapical cell arrest and mitosis. Here I described the experimental question, method and major conclusions, but without details. Note that unless the main point of the paper is to describe a new technique, the methods are seldom more than a sentence. The ellipses (? show that I have not reproduced the entire abstract here.
In summary, the Abstract should not exceed 250 words and should define clearly what is dealt with in the paper. The Abstract should:
1.    State the principal objectives and scope of the investigation (What did you investigate? Why?).
2.    Describe the methodology employed (What did you do?).
3.    Summarize the most important results (What did you find out?).
4.    State the principal conclusions and significance. (What do your results mean? So what?)
Sometimes, the first section can be omitted according to the research work you carried out, or coupled the first two sections into one or two sentence (example 2). If more than one method was employed during the experiments, the results might be integrated with each method respectively in one or more sentences (example3). The importance of the conclusions is indicated by the fact that they should be said three times: once in the Abstract, again in the Introduction, and again (in more detail probably) in the Discussion.
REQUIREMENTS, ADVICE
Do not include references to figures, tables, or sources.
Do not include information not in report.
Find out maximum length (may vary from 50 to 300+ words).
Process: Extract key points from each section. Condense in successive revisions.
Example 1
Abstract: The infection of an implanted prosthetic material can have serious consequences on the tissue integration of the implant and the scarring process in the host, and may even necessitate replacement of the prosthesis. This study was designed to explore the in vitro effects of Staphylococcus aureus (Sa) and Staphylococcus epidermidis (Se) on polypropylene (PL) and expanded polytetrafluoroethylene (ePTFE) prostheses. Fragments of PL and ePTFE were placed in a medium previously inoculated with Sa, Se or Sa + Se (1 x 10 exp 8 cfu Sa or/and Se). Bacterial effects on the biomaterials were evaluated for 30 days through scanning electron microscopy (SEM). In order to confirm the presence of bacteria on the prostheses, specimens were Gram stained and challenged with an antibody against protein-A (a specific Sa bacterial wall component). In both methods, specimens were examined by light microscopy. The presence of bacteria as microcolonies or biofilms was detected at PL filament cross-over regions after 30 days. Bacterial colonization of the ePTFE fragments was observed in internodal areas, which led to the deformation of prosthetic filaments. The present findings indicate that Sa and Se colonize the cross-over regions of the PL filaments, whereas in ePTFE prostheses, it is the internodal areas which are mostly affected. The latter areas are of difficult access to defence agents.