Expository text - How does instant photography work?

When I was a kid, my parents used to have a polaroid camera. They took pictures and shortly afterwards the image magically appeared. For those of you who, very much like me, have always wondered how this was even possible, here is the explanation.

Instant film or film for polaroid cameras is very similar to regular film. The main difference between the two of them is the developing process. While a regular film has to be developed externally, in a dark room, the instant film already has all the needed chemicals in its layers. Therefore, the picture develops as soon as it's been taken.

The film itself comprises of several different layers, as you can see in the image.

When a photograph is taken, the silver atoms on the film react with the light photons and create an image. In order to get a real picture, it needs to be developed. For this, rollers inside the instant camera spread the reagent layer, which is made of opacifiers (light-blockers), alkali (acid neutralizers), white pigment and other elements.

Underneath the reagent layer, there are three different light sensitive layers (blue, green and red). Under each of them lies a dye developer in its complementary color (yellow, magenta and cyan respectively). When a certain color of light reaches its sensitive layer, the opacifiers block the dye developer right underneath it. The other two developers can move up to the image layer.

This means that if blue light hits the blue sensitive layer, the yellow dye developer gets blocked. Therefore, only magenta and cyan reach the image layer, creating the color blue.

If you have ever seen an instant photograph develop, you know that it is usually greyish at first and only slowly becomes visible. This is due to the opacifiers. The reagent chemicals not only work their way down through the dye developers but also up through the image, timing and acid layer. The picture will stay greyish until the opacifiers and the alkali reach the acid layer where they react. This reaction makes the opacifiers become invisible and the picture visible. The timing layer slows the reagent chemicals down, leaving the picture underneath enough time to develop.

And voila, that is how instant films work. You see, it, unfortunately, has nothing to do with magic after all. 

CAJ - Different Types of Robotic Surgery

In an earlier blog post, I have explained what laparoscopic and robotic surgeries are. Now I want to tell you a little bit more about the different areas where robotic surgery can be used.

Although robotic surgery is most commonly known for being used in the abdomen area, it can essentially be used for every body part as long as you can make an incision there and insert the surgical instruments. The reason why it is mostly known for abdomen surgeries is that there are many organs in this area and the first laparoscopic surgeries where performed in this part of the body too. The surgeons knew where every organ was and had easy access in case something went wrong.

Nowadays, even heart surgeries are often performed by a surgical robot as it reduces the risks for the patients since the incisions are smaller, there is no need to crack open the chest and the surgery is being performed on the beating heart.

Even surgeries on spine or brain are no longer a problem. The University of Maryland developed a brain surgery robot that removes brain tumors safer as the machine works together with an MRI scanner granting the surgeons a better view of the tumor. This makes it easier for the surgeons to remove the tumor without endangering or harming the healthy cells surrounding it.

Overall, robotic surgery can be performed on almost every part of the body. If you can name it, it has probably already been done before. The reason why surgeons are so eager to use robotic surgery is that there are many advantages to it which allow them to perform surgeries better and more efficient and to sink risks and the amount of pain for the patients.

CAJ - Laparoscopic or Minimally Invasive Surgeries

In former times, when you underwent surgery, you usually got a souvenir in form of a huge nasty scar. Every scar is a remainder of a incision. The larger the incision the longer the healing process. They are also accompanied by a large amount of pain and a high risk of infections. Therefore, doctors are always looking for a way to keep the incisions as small and their number as low as possible. As a solution, surgeons developed the laparoscopic or minimally invasive surgery. It is also known as keyhole surgery due to the small size of the incisions. This type of surgery allows surgeons to perform operations inside the abdomen. Instead of one large incision, several smaller incisions (between 0,5-1,5 cm) are made and plastic tubes are inserted. Through these tubes, surgeons can insert cameras and surgical instruments.

The camera then transmits pictures of the patients inside on a screen for the surgeon and his team to see. Unlike in an open surgery, the surgeon does not see the organ from a top down perspective. The camera rather acts as the surgeons eye allowing him or her to inspect the organ up close and from different perspectives.

However, there is a major limitation the laparascopic surgeries: the surgeon can only work with his or her instruments and can not use his or her hands for help. For instance, the surgeon can not simply push the intestines or organs from the site of surgery as would be the case in an open surgery.
To increase the accessibility of the organ, there have been some improvements to the laparoscopic surgery, namely the advanced laparoscopic surgery with hand-access devices and robot assisted surgery.
In the advanced laparoscopic surgery, a larger incision is made, large enough for a hand to fit through and again a plastic tube is inserted. This allows the surgeon to use his hands and tactile sensation for the surgery.

The robot assisted surgery, as mentioned in the other CAJ posts, turns the surgery into a kind of video game. The surgeons sit in front of a screen with the instruments at their hands. They then performs the surgery as if it were a regular laparoscopic or open surgery with the difference that the patient does not lie right in front of them.
Basically, that is all you need to know about minimally invasive surgery. It is a good way to minimize the risks associated with surgeries and scars and although there are some drawbacks, scientists and medics are working hard to get rid of them.

CAJ - History of Robotic Surgery

The word robot comes from the Czech word "robota" and means forced labor. The term was coined by the Czech playright Karel Capek. While the robots used to be primative machines, they have come a long way since then. Nowadays, robots are able to do more complex tasks such as performing surgery.
The first documented robot-assisted surgery was performed in 1985. It was a neurosurgical biopsy and the robot PUMA 560 was used. The surgeons decided on the use of PUMA 560 because it allowed them to perform the delicate biopsy with greater precision.
                                 

In 1987, the first laparoscopic surgery was performed. It was a cholescystecotomy which is the removal of the gallbladder. Since then, robot-assisted laparoscopic surgeries, also known as minimally invasive surgeries, have been performed numerously. Laparoscopic surgeries are surgeries performed in the abdomen where the area is accessed through several small incisions instead of one large incision.



Surgery robots were revolutionized in 2000 when the FDA, the Food and Drug Administration, approved the robotic surgery system da Vinci Surgery System. The former surgical robots were large-armed and surgeons needed endoscopes and numerous surgical assistants in order to perform surgery. The da Vinci Surgery System, however, is an all-encompassing system of surgical instruments and camera or scopic utensils.

As you see, robotic surgery is not so new as you might think. What started as a large armed robot has become a multi-armed machine which allows surgeons to perform even really complex surgeries with great precision. It is only a matter of time until they are able to perform surgeries completely on their own.

How to stop someone from killing Hitler

Estimated time: several years

Needed equipment: a time machine, a history book, charisma, CPR skills

1. Look up in your history book where and when Hitler was killed and by whom.
2. Think of several plans on how you can save Hitler.
3. Pick a date and time when you want to meet Hitler.

Tip: Choose a date a couple of years prior to the assassination. This leaves you with enough time to befriend Hitler and become one of his closest companions. This way he will always keep you close by, improving the chance of you being able to save him.

4. If you have decided on the ideal day to meet him, set the time machine to said date.
5. Enter the time machine and travel back.

Tip: Always keep your time machine close by in case you need a redo or to abort the mission.

6. Meet Hitler and try to become friends with him right away.
7. If he does not like you immediately, stay consistent. If necessary, join the military and slowly work your way up.

Warning: The latter might involve hard work and violence. If you feel uncomfortable with either, abort mission.

8. Once you have successfully become Hitler’s best friend, follow him everywhere.
9. When the day of the planned assassination arrives, you have two choices: take care of the assassinator before he gets the chance to kill Hitler or let him try and revive Hitler afterwards.

Tip: If you choose the first option, your deed will probably go unnoticed. Choosing the latter option, however, will make you a national hero and Hitler will forever be in your debt.

10. If you choose the first option, locate the suspect and rid yourself of him. This is best achieved by tipping off the Gestapo and he will either be arrested and/or shot. Your job is done and you return to your own time.
11. If you would rather become a hero and take all the glory, let the perpetrator try to kill Hitler.
1. Revive Hitler.

Tip: If you do not get it right the first time, wait until you are alone and travel back in time. Repeat until you manage to save Hitler.

12. Congratulations! You have now successfully saved Hitler’s life.

Camera Lucida - How helpful were the instructions?

Tim Hunkin’s instructions on how to make a camera lucida appear to be easy to follow due to the pictures and the text accompanying them. However, the set of instructions turns out to be rather confusing when examined more closely. Firstly, the instructions given are incomplete. For example, the instructions mention a hole to look through although said hole was never mentioned before. Similarly, the installation of the reflecting plastic plate is missing. The author probably left these steps out purposely as they seemed obvious to him. To someone who has never  built a camera lucida before, however, these steps are essential. It would also have been more helpful to number the steps, even if the text is very short. Another confusing aspect that the reader constantly has to jump between the text and the pictures. Neither text nor pictures are sufficient on their own to explain how the camera is built without causing utter confusion. Overall, the text itself is not badly written. It is concise and understandable, but the fact that it is only partially complete makes the instructions rather difficult to follow.

CAJ - Abstract

This CAJ looks into the field of surgical robots, such as the DaVinci robot, and the surgeries which are already practiced by them. Furthermore, it focuses on the extensive training surgeons have to undergo to operate these robots and the advantages as well as the disadvantages of the surgical robots themselves. The CAJ gathers its information from videos, special blogs as well as academic papers. It comes to the conclusion that although the training for the surgeons is very time consuming and the robots are expensive, risks and complications have dropped significantly for the patients. They recover quicker, are able to leave the hospital earlier and overall encounter less pain. Overall, surgical robots hold many advantages for the patients which is why they are likely to spread and become used more frequently.

CAJ - Introduction

As my CAJ topic, I've decided to choose the DaVinci robot. It is a surgical robot which allows surgeons to perform complicated surgeries even better, comes with fewer side effects than regular surgery and is already in use for a variety of surgeries. Over the semester, I will talk about the advantages as well as the disadvantages of surgical robots, the complex, yet pretty awesome training surgeons have to go through in order to be able to operate the robot, and what kind of surgeries are already possible with it. So look forward to the next blog posts because it's a pretty interesting topic and let's be honest, who wouldn't want their surgery done by a nice Dr. DaVinci turning your surgery into a kind of video game?! ;)