Do you remember the detective polices use DNA fingerprinting assisting information to find the murder in Crime Scene Investigation drama? DNA fingerprinting is one of the techniques of DNA profiling, to offer personal information of suspects. DNA profiling is a common forensic method to support criminal investigation, such as parentage testing and the DNA database. However, DNA profiling consists of the ethical- legal problems of the DNA database.

Positive effects of DNA profiling

DNA profiling can track an old case murder because of the long-persistent DNA information. In a crime scene, the polices collect biological samples, including blood, hair and figure printing, then the DNA information is obtained from DNA agarose methods and saved in files until match suspects. In the United Kingdom, the polices found the murder of the case 10 years ago, based on a little blood on the victim.

DNA profiling can find an unknown murder all over the world because of an improved international DNA database online. In early this year, the policemen capture a killer via an online DNA database. The genetic genealogists achieved genetic information from the collected blood on the scene and predict aspects of a person’s physical appearances through the database so that the detectives find the murder from predicted personal characters.

DNA profiling progress

Negative effects of DNA profiling

Fake DNA marks take a negative effect on a murder determination, these fake information leads to an obstacle of finding the suspects and let criminals go unpunished. In 1992, a criminal placed others’ DNA information on the scene and polices cannot charge him due to the differences in DNA evidence.

DNA databank of DNA profiling leaks personal information. DNA database collects DNA information of victims, witnesses and criminals, some hackers get these personal characters for either selling or post in the public. Therefore, personal health and confidential information of people leak to the public.

Summary

On one hand, DNA profiling can take benefits of finding a murder a long time ago and an unknown murder without physical characteristics. On the other hand, DNA profiling leaks innocent personal information and provides wrong evidence, which leads the criminals unpunished.

DNA profiling should take it seriously as scene evidence.

Posted in Molecular Biology & Biotechnology

Tagged DNA investigation, hacking

In January of this year, China used 3D printing for a bridge construction where people can walk through as the picture below. 3D printing becomes popular, applying in varieties of objects, small daily objects and even large materials. However, what else we can use 3D printing for? Could 3D-printing apply in a medical field?

3D Printing Bridge in China 2019

Traditionally, kidney diseases are demanding kidneys for saving human lives, as scientists stated that more than 100,000 adults and 1500 children waiting for lived kidney by 2014, as the following picture states, the number of patients is still increasing. However, not to surprise, the number of kidney donors cannot support the needs of kidney patients, only 30 % of patients might get a chance for transplants and around 10 % of patients died during the waiting time, shown right below the picture.

An increasing number of kidney patients

Three‐year outcomes for adults waiting for a kidney transplant in 2011 (DD, deceased donor; LD, living donor)

As reported by Japanese researchers, organ acceptors can perform transplants only after their health conditions match the organ donors, such as blood type. The limitation of organ transplants makes it more difficult for kidney patients. But, what if we can make a kidney by 3D bioprinting?

Currently, lots of experiments are seeking the potential possibility of organ bioprinting. 3D bioprinting can cure kidney disease easier comparing to waiting for kidney donors. In 2011, Dr. Altia successfully used engineered bladders (key parts of a kidney) via bioprinting to save a boy called Luke Massella 10 years ago. In a TED show, Dr. Altia’s group produces a whole human kidney by bioprinting in only 40 minutes. This bioprinting technique can fulfill the needs of kidneys.

TED Talk, printing a human kidney

In the next few years, kidney patients will not require to wait for the matched kidney donors for transplants and bioprinting-kidneys will help them get a healthy life.

Posted in Health

Tagged Bioprint, kidney

Can you image yourself eating plastic but you cannot digest it and suffer from the plastic? You probably say yes and think that this situation will never happen in your life. However, plastic is currently damaging the marine animals and birds’  lives. You might have seen an image of a dead bird with full of small plastic in its stomach.

Plastic pollution is becoming serious these years, especially plastics in small sizes. Scientists estimated that plastic debris will reach around 250 million into the ocean and the debris is destroying the marine environment and marine lives, such as sea turtles and seagulls. Animals take the plastics as food by accident and die from not digesting them.

Plastic straws as a part of plastic pollution, in the last 50 years, they are popular in lives. people commonly drink Coca Cola or iced coffee with plastic straws. To reduce the usage of plastic, Vancouver will ban plastic straws at the beginning of 2020, is anything alternative to plastic straws?

Yes. Rice straws, made from rice and tapioca powder, can be alternative to plastic straws. As the company’s CEO Kim mentioned that the straws as 100% biodegradable product can be decomposed in 100 days compared to plastic straws decomposing around 1500 years. People can spend only 0.03$ on each rice straw and the price will be cheaper as stated by Kim.

Rice straws are eco-friendly alternatives to replace the plastic ones. As one of the advantages,  people can enjoy beverages with rice straws and even eat them after using them. Currently, many restaurants apply rice straws and the new straws are sold in Canada. Next time, when you want to drink cola, try to use rice straws.

Posted in Environment

Tagged: plastic recycling, straws

Plastic pollution is one of the most serious problems in the world and everyone should consider the plastic problem in daily life.  Scientists estimated that around 250 million plastic debris into the ocean and the debris is destroying the marine environment and marine lives, such as sea turtles and seagulls.

Plastic straws as a part of plastic pollution, in the last 50 years, plastic straws are popular in lives, people commonly drink Coca Cola or iced coffee with plastic straws. To reduce the usage of plastic, Vancouver will ban plastic straws at the beginning of 2020, is anything alternative to plastic straws?

Paper straws are invented before plastic straws and are commonly used to replace the plastic straws. However, paper straws are not easy to recycle either, we will require a better recycling system. BBC News states that Mcdonald‘s paper straws cannot recycle because of the thickness of drinking tubes. What else alternatives for plastic straws?

In the previous year, a European company invented pasta straws to replace the abandoned plastic straws and these special straws made from spaghetti. As the news state, the taste of straws is normal when they drink a cold beverage and they can eat the pasta straws if they boil them. This straw is more expensive compared to plastic but it is decomposed.

Photo: Stroodles

Recently, a Korean’ s company designs new straws. The rice straws are made by rice four and tapioca powder. People can eat these straws or the straws can be decomposed in 100 days. Each rice straw costs 0.03 $ while the plastic straw costs 0.01-0.02 $. As the company’ CEO Kim mentioned that the price of the straws will decrease when the productivity increases in the future.

In general, bamboo straws, stainless steel straws and glass straws are also the alternatives of plastic straws. Most of plastic straws alternatives are more eco-friendly, but they are more expensive and inconvenient. Therefore, a better alternative plastic straw or an improved alternative plastic straw will be required in the future.

Posted in Environment

Tagged: plastic recycling, straws

Bai Jingwen(Vivienne): 55932164 vivienne

Mengmeng Li(Astrid): 59418160

Xuechun Lu: 41519166

Cuishan Xu(Tracey ):32182164

Integration and antidifferentiation are commonly conflated since it’s generally misunderstood that they are both the inverse of differentiation. However, they are totally different in their exact definitions, despite that they are indeed connected in some way. Integration is the process of calculating integrals, i.e. the area under a fixed curve, which is a number. Whereas antidifferentiation is the process of finding the antiderivatives of a function, which are a number of functions. Comparing these two vague definitions, it can be assumed that antidifferentiation is not equal to integration.

What is antidifferentiation ?

Antidifferentiation  can be understood as the inverse of differentiation.

For a function f(x), the antiderivative (primitive function) of this function, f(x)dx, are a group of  functions F(x)+C that satisfies the derivative of this group functions is f(x). f(x)dx=F(x)+C. So the antiderivative of f(x) is not unique.

example:

                f(x)=1                                           F(x)=x+c. (F(x) could be F(x)=x+1, F(x)=x+2… )

What is integration?

For integration, integral can be defined by Riemann Sum.

let f(t) dt defined on a closed interval [a, b] and divide  [a, b] into n sunbintervals

with the same t value, choose a sample ponit ti* within [ti-1,ti], so that the area of one rectangles isf(ti*)t, so the area of these rectangles is  ninfi=1nf(ti*)t.

Given a continuous function f(x) and an interval [a, b], the meaning of  integral abf(x) dx is the area of curve trapezoid formed by function f(x), x=a , x=b and x-axis in x-y plane (as illustrated in this picture).  So integration is a certain real number.

What is the connection between integration and antidifferentiation ?

Integration and antidifferentiation are correlated by Fundamental Theorem of Calculus (FTC) since an integral can be evaluated by using antiderivatives. As  FTC2 said, if G(x) is an antiderivative of f(x), then we have,

This means to evaluate the integral of continuous function f(x) defined on [a, b], we just need to take antiderivative of the function. In this way, after finding an antiderivative of a function, we can simply plug in x=b and x=a, and subtract these two values. Hence it is where they are connected that antidifferentiation can be used in calculating integrals.

Why students commonly mistake “Integration”& “Antiderivation”?

• Students do not know what is the definition of the two, and get confused whether integration is the same thing as derivation.
• The way to take antiderivative is part of integral (FTC) so students may   misunderstand the two concepts.

Bai Jingwen(Vivienne): 55932164 vivienne

Mengmeng Li(Astrid): 59418160

Xuechun Lu: 41519166

Cuishan Xu(Tracey ):32182164

Motivation of integration

Integration is used to calculate the area under a certain line, curve or the area which covered by an image in math. Like calculating the area for a piece of leaf. When we doing integration, we separate the leaf to a lot small rectangle strips whose area can be easily calculated. Approximately, the sum area of strips is area of the leaf. Moreover, integration can be used to calculate a curve’s length by regarding the curve to a lot short straight lines. As an important math concept, not only can it be applied in math to calculate area and length and in physics to calculate the movement about one subject, it can also be applied in our daily life observation.

It was a sunny day, our team was eating in the Orchard Common, and we found it that there is a big irregular hole (the depth varies) on the table. Everyone wanted to know the exact volume of plastic material do the staff in dining hall need to fill this hole. At the same time, Tracey was eating French Fries, she was thinking “Oh why not fill the hole with fries so as to calculate the volume by calculating the volume of fries?”. It is noted that French Fries has the same length and width but different height and the height of fries could be cut to fit the depth of the hole.

To calculate the volume of the hole, firstly we put a cardboard under the hole so as to accommodate the fries in case they fell on the ground. And then the filling started from the side of the hole. We put fries into the hole and compared the height between the fries and the depth of the hole. The extra parts were eaten by Tracey. And repeat the procedure. Finally, the irregular hole was full. Now Tracey put all the fries from the hole on the plate in order. Vivienne yelled that, it is the volume of the hole, we can calculate the total volume by adding the volume of fries one by one. It’s obvious that the volumes of different fries are easy to calculate once knowing the fixed length & width and the various heights. This is a normal case in daily life.

Like the volume of a hole we saw in our dining hall. We can separate it in small pieces and get the hole’s volume by calculating every small piece’ volume. The method is just the basic content of integration. Integration, in total, is a method to make complicate things easier by making it smaller. Thinking of puzzles, every little piece of puzzle can be connected together to a masterpiece. By using the way to integrate something, we can approximately get the value which is hard to get straightly.

teammates: Mengmeng Li (Astrid) 59418160

Jingwen Bai (Vivienne) 55932164

Cuishan Xu (Tracey) 32182164

Xuechun Lu(Leonie) 41519166

The secret of doing this math question, it is important to understand what we have first and use the power of consecutive information from the Q1 to Q3. And think about when we Stacked woods to build up something like a house, we need to put one block and follows by another block after that, and we get what we want finally. Or something like playing dominoes, you can get the final result after one block after another block. Otherwise, you skip one of the block, it is impossible to get an amazing result, just like this math problem. We need to focus on the continuity of everything we have already known. Think about what we have from the questions of one and two. And keep the continuity to figure out the solution of question 3. By this way, answers will appear immediately.

• what distinguishes convergent sequences from divergent sequences, and

1. The definition of consequence: A sequence {an}={a1,a2,a3…an} is ordered list of elements with a very element but no lost element .We say that limx→∞ an = L,or {an}converges to L. If an is arbitrarily close to L provided n is sufficiently large. A sequence that does not converge is said to diverge.
2. So we can say if a sequence is close to a number, it is convergent, but if a sequence is infinite, it is divergent.
3. When we look at a sequence, we can see sequence will have different kinds of highest or lowest points, like 0, 1, 2, 3, 4…….

If a sequence without a highest or lowest point even does not get close to a top or low point, it must be divergent.

When we see a graph of convergent sequence, take it as an example of an=sin(x)/x, a following graph show, it has many top and low point, and the points are continually close to a point which is the L as we said before. Also , if we consider the top and low points as that there are two friends who want to meet each other from the top and feet of mountain, and they decide to meet each other at a point between their positions by taking cable car. So the lower points will increase and the high points will decrease because of their meeting later. Of course, their distance become closer and closer.

On the otherwise, if a sequence is divergent, it is like that two people take cable car and their distance becomes larger and larger.(distance of cable car)

(b) what distinguishes convergent series from divergent series. Series are something sum of an, like =a1, a1+a2,a1+a2+a3… . If they are convergent, they can get a certain number as L, if they are divergent, they may be infinite. We have many types of test to test, like ratio test, comparison test, divergent test…..to decide which is divergent or converge. Also, we can use a simple word to understand. If you draw a graph, like {1/n^2), if you put cake there, you will find the size of the cake becomes smaller and smaller, but is you series like ={2^n}, you will find the size of cake becomes larger and larger.

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