The word “respectively” can be useful in scientific writing to clarify relationships between several different words in a sentence. It’s used to indicate to the reader that the relationship between two sets of words or phrases can be read in terms of the order in which they appear.

Huh?

It might be easier to explain with an example. In this case, I’ll use colors to show you the relationships that are implied between two sets of nouns when you use the word “respectively” at the end of a sentence.

Example: “The peak absorption wavelengths of samples A and B were 710 nm and 600 nm, respectively.”

So in this sentence, we have a set of samples (A and B) and a set of numbers (710 nm and 600 nm). The word “respectively” tells the reader that the samples and numbers that correspond to one another occur in the same order in which they appear. So the first value (710 nm) corresponds to the first sample (A). Likewise, the second value listed in the sentence (600 nm) corresponds the second sample (B).

Let’s do another example.

Example: “The dog and the cat were named Jack and Sam, respectively.”

So what is the dog’s name? And what's the cat’s name?

Since the dog is listed first in the sentence, the word “respectively” lets you know that the dog’s name also corresponds to the first name that’s written (Jack). And since the cat is listed second, its name would be the second name listed in the sentence (Sam).

A note on punctuation: the word "respectively" is put at the end of the sentence or phrase it refers to, and it is set off with a comma (or commas if "respectively" occurs in the middle of the sentence).

Example: The dog and the cat were named Jack and Sam, respectively, and they lived down the street from me.
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If you have any doubts about how to use “respectively” in a sentence, I suggest you avoid using it so you don’t unintentionally confuse the reader. It can be a useful writing tool, but it's often not necessary. The sentence can usually be re-written in another way to express the same information.

If you would like to learn more writing tips and tricks, check out my PowerPoint presentation An Introduction to Writing in Science, available in ebook format on the Amazon Kindle app. 

Acronyms are a type of abbreviation that are typically constructed from the first letters of the individual words in a phrase.

Example: single-walled carbon nanotube = SWCNT
(I’ve underlined the letters for emphasis only)

These abbreviations can also include letters from inside the word (as in nanotube), particularly when that word could be broken down into two individual parts that have meaning on their own (e.g., nano and tube).  

Acronyms can be useful in science so you don’t have to repeat long phrases like “single-walled carbon nanotubes” 50 times throughout a manuscript. However, you should follow these rules if you’re going to use them in your writing:

1) USE ACRONYMS SPARINGLY

Many scientists have a tendency to over-use acronyms, possibly because they believe that shortening phrases will make the work easier and faster to read, but this couldn’t be further from the truth.

The issue is that acronyms are essentially a code – they stand for some other idea. But readers have a hard time keeping track of multiple codes. If they forget what your acronym stands for, they’ll have to go back to where it was first defined in the paper, which is time-consuming and annoying. Or (and this is the much more likely scenario), they will simply give up and stop reading your work, because it’s too difficult to memorize so many new terms.

Don’t give readers an excuse to stop reading. Make their life easy. Define only the acronyms that are absolutely essential to communicate your work efficiently.

Generally, this means limiting acronyms to sample names or concepts that are unique to your research.

Example: carboxylic acid-functionalized gold nanoparticles = COOH-Au-NPs

In this example, I used the common chemical abbreviation for carboxylic acid groups (COOH), the elemental symbol for gold from the periodic table (Au), and then a simple acronym for nanoparticles (NPs).

You can see how the use of too many of these kinds of acronyms could become fairly confusing for the reader, who may not immediately intuit what COOH-Au-NPs means. However, you can expect them to easily learn one or two such abbreviations in the paper. 

As a rule of thumb, I would limit the number of new acronyms you define to three or less for a journal-length publication (~3000-6000 words). That doesn’t include well-accepted acronyms, like DNA and NMR, just the terms that are wholly original to your own work. 

2) Define the acronym on first usage, then use it exclusively throughout the text after that point.

What do I mean by “define the acronym?” I mean you need to write out the full term or phrase once on first usage, then put the acronym you would like to use in parentheses following this phrase.

Example: Although Sumio Iijima is usually credited with discovering carbon nanotubes (CNTs), the history of these unique materials extends back almost 40 years prior.

After you define the acronym, you must use it throughout the text thereafter. You can’t switch back and forth between the full phrase and the abbreviation. Once the acronym is defined, you are somewhat locked into using it (with exceptions based on journal-specific guidelines for headings and captions).

Example: Carbon nanotubes (CNTs) are a one-dimensional material made of sp2-hybridized carbon. These nanomaterials can be more conductive than copper. CNTs also fluorescence in the tissue-transparent region of the near-infrared, suggesting potential applications in bio-imaging. However, the difficulty in processing CNTs has limited such proposed uses.  
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Because you’re locked into using the acronym once defined, that’s why it’s a bad idea to use too many acronyms or to define acronyms for words or phrases that are fairly common. Otherwise, your writing will become riddled with unnecessary abbreviations, which can be awkward to read or distracting.

So keep it simple. Define acronyms sparingly on first usage and then use them thereafter throughout the text. 

Hope this helps!

If you would like to learn more writing tips and tricks, check out my PowerPoint presentation An Introduction to Writing in Science, available in ebook format on the Amazon Kindle app. 

Scientists, lay-people, non-native and native English speakers alike tend to confuse the words “effect” and “affect” in their writing. To use these words correctly, you only need to remember two things:

1)  The word “effect” is generally a noun. It means to be a result or a consequence of     something.

2) The word “affect” is a verb (as in “to affect”). It means to influence.

In scientific writing, these two rules virtually always apply. Go ahead and memorize them. “Effect” is a noun, “affect” is a verb.

So as you’re writing and you’re not sure whether to use the word “effect” or “affect,” just ask yourself, are you trying to use the word to convey a thing (i.e., a noun) or an action (i.e., a verb)?

The addition of salt did not effect/affect the reaction.

In this instance, is the red text trying convey a thing or an action?

In this case, it’s an action. So the word needs to be a verb, which means you should use “affect." You can double-check by making the sure the word “influence” could also be inserted into the sentence without changing its meaning.

The addition of salt did not affect the reaction.

The addition of salt did not influence the reaction.

Bingo. “Affect” is definitely the correct word to use in this instance.


Let’s do another example:

UV light had no effect/affect on the reaction.

In this instance, should the word be a noun or verb? I can tell it’s a noun because of the verb “had” that comes before it, in which case the correct usage would be “effect.”

Still having some trouble?

Try this: could you in theory put either “the” or “an” before the word in question? If so, the word is a noun, and the correct usage is therefore "effect." To do this test, don’t let other words like adjectives in the sentence confuse you. In fact, let’s remove the adjective “no” from the sentence, and then try putting the word “the” or “an” in front of the red text.

UV light had an effect/affect on the reaction.

That sentence is grammatically correct, therefore we know the red text is being used as a noun, hence we would write “effect” in this case. (Let’s go ahead and put the word "effect" back into the original sentence.)
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UV light had no effect on the reaction.
 
Note: In some contexts, largely outside of science, there are some exceptions to this noun/verb rule. For example, the word “effect” can occasionally to be used as a verb, in which case it means to “bring about” or “to cause.” However, using “effect” as a verb tends to sound overly technical and even pretentious, which is why I would suggest you avoid using it this way.

Just stick to the effect = noun and affect = verb rule and you’ll be good to go. 

If you would like to learn more writing tips and tricks, check out my PowerPoint presentation An Introduction to Writing in Science, available in ebook format on the Amazon Kindle app. 

I thought it would be interesting to start a blog series in which to discuss common writing mistakes I see while editing scientific manuscripts. Learning a few simple rules can make the writing process just a little less daunting, so maybe this series will help you.

Here's one of the most prolific errors I see when I edit: i.e. vs. e.g. 

What's the difference between these two abbreviations and when do you use them?

First, let's define these terms. I won't bother literally translating the full latin words, let's keep things simple. All you need to remember is this:

• "i.e." means "in other words" 
• "e.g." means "for example"      (thank you Grammar Girl for this great trick)

So when do you use "i.e." and "e.g.?"

Scientists often like to clarify their writing by adding a parenthetical aside in or at the end of a sentence. This is perfectly fine to do, and it's often very helpful (though be careful about over-doing it). Here's an example:

"Carbon nanotubes have many applications in biology (e.g., drug-delivery and near-IR fluorescence imaging)."

Adding "e.g." to the beginning of the parenthetical statement signals to the reader that the following words are an example of what you've just stated in the sentence. So you can read it as:

"Carbon nanotubes have many applications in biology (for example, drug delivery and near-IR fluorescence imaging)."

What if I were to replace "e.g." with "i.e." in that sentence?

"Carbon nanotubes have many applications in biology (i.e., drug-delivery and near-IR fluorescence imaging)."

It would be incorrect, because the statement would be read as:

"Carbon nanotubes have many applications in biology (in other words, drug-delivery and near-IR fluorescence imaging)."

That doesn't sound right, does it? Drug-delivery and fluorescence imaging aren't actually other words for different applications of carbon nanotubes. They're examples. 

Why is this important? After all, isn't the meaning clear enough when we use these abbreviations? Does it really matter which one you use?

I'd say yes, because scientists have to be precise, whether in their experiments or their writing. It's important to say exactly and not approximately what you mean.

Also, there are many scientists who have a deep knowledge of grammar and will notice these kinds of mistakes in your manuscripts. You might think these errors are small and insignificant. However, a grammar-minded scientist who is reviewing your work might consider the writing sloppy if they see a large number of these kinds of mistakes and perhaps unfairly also question the precision of your research. Don't give the reviewer any reason to get in a bad mood, especially when it is so easy to learn the difference between "i.e." and "e.g." 

So as you write, and you want to use one of these abbreviations, read the sentence aloud and consider whether it makes more sense to say "for example" or "in other words." Then use the appropriate abbreviation.

p.s. A note on punctuation.

You'll notice in those previous examples that I put a comma after the abbreviations.

So it's "(e.g., drug-delivery)," not "(e.g. drug delivery)."

Again, it's a small thing, but precision counts. I could explain to you why you use a comma here (it has to do with restrictive vs. non-restrictive clauses), but don't worry about it.

Just remember that "i.e." and "e.g." are followed immediately by a comma.

If you would like to learn more writing tips and tricks, check out my PowerPoint presentation An Introduction to Writing in Science, available in ebook format on the Amazon Kindle app.