Nerdy Science Blog

Attention all tech geeks, you might use your computer to write things these days, but sometimes you do need to use pencil to jot something (for example in the middle of the game).  As you used to typing, you often make mistakes in writing.  You need a really cool eraser to help you to erase your mistakes, which is “Delete Key Eraser”.  Delete Key Eraser looks like a delete key on the keyboard, which reminds you of your familiar keyboard.  There are several similar erasers available online:

1. Tersumus Delete Key Eraser

The price for this 3.5″ x 1.75″ x 1″ eraser is $12.99.  This high quality rubber eraser can erase pencil writing easily (obviously) but not ink pen writing.  You can’t use this eraser to erase anything from your monitor even though it resembles a Delete Key.

2. Delete Key Eraser

Compared to the above eraser, this one is cheaper.  It costs only $2.50 each and it does not feel like plastic.

Original letter of endorsement:

An Open Letter to the American People
September 25, 2008
This year’s presidential election is among the most significant in our nation’s history. The country urgently needs a visionary leader who can ensure the future of our traditional strengths in science and technology and who can harness those strengths to address many of our greatest problems: energy, disease, climate change, security, and economic competitiveness.

We are convinced that Senator Barack Obama is such a leader, and we urge you to join us in supporting him.

During the administration of George W. Bush, vital parts of our country’s scientific enterprise have been damaged by stagnant or declining federal support. The government’s scientific advisory process has been distorted by political considerations. As a result, our once dominant position in the scientific world has been shaken and our prosperity has been placed at risk. We have lost time critical for the development of new ways to provide energy, treat disease, reverse climate change, strengthen our security, and improve our economy.

We have watched Senator Obama’s approach to these issues with admiration. We especially applaud his emphasis during the campaign on the power of science and technology to enhance our nation’s competitiveness. In particular, we support the measures he plans to take – through new initiatives in education and training, expanded research funding, an unbiased process for obtaining scientific advice, and an appropriate balance of basic and applied research – to meet the nation’s and the world’s most urgent needs.

Senator Obama understands that Presidential leadership and federal investments in science and technology are crucial elements in successful governance of the world’s leading country. We hope you will join us as we work together to ensure his election in November.

Signed,

Alexei Abrikosov Physics 2003
Roger Guillemin Medicine 1977
Peter Agre Chemistry 2003
John L. Hall Physics 2005
Sidney Altman Chemistry 1989
Leland H. Hartwell Medicine 2001
Philip W. Anderson Physics 1977
Dudley Herschbach Chemistry 1986
Richard Axel Medicine 2004
Roald Hoffmann Chemistry 1981
David Baltimore Medicine 1975
H. Robert Horvitz Medicine 2002
Baruj Benacerraf Medicine 1980
Louis Ignarro Medicine 1998
Paul Berg Chemistry 1980
Eric R. Kandel Medicine 2000
J. Michael Bishop Medicine 1989
Walter Kohn Chemistry 1998
N. Bloembergen Physics 1981
Roger Kornberg Chemistry 2006
Michael S. Brown Medicine 1985
Leon M. Lederman Physics 1988
Linda B. Buck Medicine 2004
Craig C. Mello Medicine 2006
Mario R. Capecchi Medicine 2007
Marshall Nirenberg Medicine 1968
Stanley Cohen Medicine 1986
Douglas D. Osheroff Physics 1996
Leon Cooper Physics 1972
Stanley B. Prusiner Medicine 1997
James W. Cronin Physics 1980
Norman F. Ramsey Physics 1989
Robert F. Curl Chemistry 1996
Robert Richardson Physics 1996
Johann Diesenhofer Chemistry 1988
Burton Richter Physics 1976
John B. Fenn Chemistry 2002
Sherwood Rowland Chemistry 1995
Edmond H. Fischer Medicine 1992
Oliver Smithies Medicine 2007
Val Fitch Physics 1980
Richard R Schrock Chemistry 2005
Jerome I. Friedman Physics 1990
Joseph H. Taylor Jr. Physics 1993
Riccardo Giacconi Physics 2002
E. Donnall Thomas Medicine 1990
Walter Gilbert Chemistry 1980
Charles H. Townes Physics 1964
Alfred G. Gilman Medicine 1994
Daniel C.Tsui Physics 1998
Donald A. Glaser Physics 1960 Harold
Varmus Medicine 1989
Sheldon L. Glashow Physics 1979
James D. Watson Medicine 1962
Joseph Goldstein Medicine 1985
Eric Wieschaus Medicine 1995
Paul Greengard Medicine 2000
Frank Wilczek Physics 2004
David Gross Physics 2004 Robert
W. Wilson Physics 1978
Robert H. Grubbs Chemistry 2005

The views expressed in this letter represent those of the signers acting as individual citizens. They do not necessarily represent the views of the institutions with which they are affiliated. The Medicine award is for “Physiology or Medicine.”

Even though James D. Watson said that blacks are genetically dumber than whites, he still support Obama.

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Chemotherapy – in the general sense, means using chemical agents to kill cells, and in most cases, specifically those of cancer. In its non-oncological use, the term may also refer to antibiotics, used to kill micro-organisms.

Brief History
History of chemotherapy can be traced back to the discovery of nitrogen mustard (used as a chemical warfare agent), as an effective treatment of cancer. Two pharmacologists, Louis S. Goodman and Alfred Gilman had discovered lymphoid and myeloid suppression on people exposed to the mustard gas. Soon after that, they tried to inject a related agent, called mustine, into a patient with non-Hodgkin’s lymphoma. They then documented the significant reduction in the patient’s tumor masses. After World War II, Sidney Farber, a pathologist at Harvard Medical School, together with Harriett Klite and Lederle Laboratories chemists, used folate analogues (now methotrexate), which is antagonistic to folic acid, to block the function of folate-requiring enzymes. This analogue became the first drugs to induce remission in children with Acute Lymphocytic Leukemia.

What is cancer?
Before we proceed into knowing how chemotherapy works, types of chemotherapy and its side effect, it is important to know the definition of cancer. Cancer can be defined as the uncontrolled growth of certain group of cells with malignant behavior like invasion and metastasis. Metastasis is the spread of a cancer from one organ or part to another non-adjacent organ or part. Invasion is the spread of a cancer to another adjacent organ.

Mechanism of action of chemotherapy
Chemotherapeutic drugs damage cell divisions, called mitosis, and effectively affecting cells which are dividing in a fast pace. The drugs are termed cytotoxic because they cause damage to the cells. Some of them cause apoptosis of cells (programmed cell death). As chemotherapy affects cell division, high growth fractions tumors are more sensitive to chemotherapy. Malignancies with slower growth rates tend to respond to chemotherapy much more modestly. The same concept can be used to explain why chemotherapy affect ‘younger tumors’ more effectively. It is because the mechanisms regulating cell growth are usually still preserved. With succeeding generations of tumor cells, the differentiation is typically lost and growth become less regulated, and tumors become less responsive to most chemotherapeutic agents.

Objectives of Chemotherapy
There are few kinds of strategies in the administration of chemotherapeutic drugs for desired effects:

1. Combined modality chemotherapy – chemotherapeutic drugs are used together with other cancer treatments like radiation therapy or surgery. Most of the cancer patients receive this kind of treatment now. Combination chemotherapy also involves treating the patient with a number of different drugs simultaneously. The advantage of this type of strategy would be the ability to minimize the chances of resistance developing to any one agent.
2. Neoadjuvant chemotherapy – chemotherapeutic drugs are used with the aim to shrink the primary tumor, so that local therapy like surgery or radiotherapy will be less destructive and more effective. This strategy is also one kind of preoperative treatment.
3. Adjuvant chemotherapy – chemotherapeutic drugs are used when there is little evidence of cancer present, but there is risk of recurrence. Adjuvant chemotherapy is usually given postoperatively. During this period, the newly growing tumors are fast-dividing, and therefore very susceptible. This can also help to reduce chances of resistance developing if the tumor does develop.
4. Palliative chemotherapy – chemotherapeutic drugs are given without curative intent but simply to decrease tumor load and increase life expectancy.

Most of the chemotherapeutic drugs today can be divided into antimetabolites, topoisomerase inhibitors, anthracyclines, plant alkaloids, alkylating agents and other antitumor agents. These mentioned groups of drugs affect DNA synthesis or cell division in some way. Some newer chemotherapeutic agents like monoclonal antibodies and the tyrosine kinase inhibitors (e.g. imatinib mesylate) do not directly interfere with DNA. They target a molecular abnormality in some types of cancer for example gastrointestinal stromal tumors and chronic myelogenous leukemia.

Different types of chemotherapeutic drugs

Alkylating antineoplastic agent
Alkylating agnets are active under conditions which are present in cells. The mechanism makes them toxic and allows them to be used as anti-cancer drugs. They stop the growth of the tumor by cross-linking some of the nucleobases in the double-helix strands of the DNA., directly destroying the structure of DNA. This makes the strands separated and thus unable to divide. Examples: Busulfan, Cyclophosphamide, Mechlorethamine, Cisplatin and etc.

Antimetabolites
An antimetabolite is a similar structure required for normal biochemical reactions, yet different enough to interfere with cell division. They masquerade as purine or pyrimidine – which are the building blocks of DNA. They prevent these substances becoming incorporated in to DNA during S phase of the cell cycle and thus stopping normal development and division.

Anthracycline
Antrhacycline inhibits DNA and RNA synthesis by intercalating between base pairs of the DNA/RNA strand, inhibits topoisomerase II enzyme, preventing the relaxing of supercoiled DNA thus blocking DNA transcription and replication, and creates iron-mediated free oxygen radicals that damage the DNA and cell membranes. However, their main adverse effects are heart damage (cardiotoxicity) and vomiting. These adverse effects limit their usefulness. Some of the available agents include: Daunorubicin, Epirubicin and etc.

Topoisomerase inhibitor
These isomerase enzymes act on the topology of DNA. There are 3 kinds of topology: supercoiling, knotting and catenation. When outside of replication or transcription, DNA is kept as compact as possible. Topoisomerases upsets the proper DNA supercoiling during transcription and replication. Examples: irinotecan, amsacrine, etoposide and etc.

Monoclonal antibodies
By creating monoclonal antibodies that bind only to specific antigens of the cancer cell, immunological response could be induce, against the target cancer cell. Example: trastuzumab (anti-cancer therapy for a specific kind of breast cancer), alemtuzumab (used in B cell leukemia), gemtuzumab (use during relapsed acute myeloid leukemia).

The side effects of chemotherapy differ for each drugs, drug’s doses and individuals.
Some of the common side effects of chemotherapy are: nausea, vomiting, hair loss, fatigue, anemia, mouth sores, taste and smell changes, infection, diarrhea, infertility, fluid retention, rashes, irritated bladder, swelling, soreness of mucous membranes, numbness, aching joints and etc. Thus, it is important for each individual to research on each drug before trying them as side effects varies for each of them. Even though chemotherapy is designed to kill cancerous cells, it is so aggressive that it works against healthy cells as well. Since chemotherapeutic drugs travel everywhere in the body, damage of healthy cells can occur at various places in the body.

Proper diagnosis of cancer and careful administration of chemotherapy should be practised to ensure that the benefits of the therapy outstrip its unwanted effects.

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Visual learning is a good technique to enhance learning.  With the mushrooming of users generated video websites, there are more information that public can access to learn new things.  How you know one of those videos your children or you are watching contains the correct information?

ScienceHack will ensure every science you are watching there are accurate.  Scientists from different fields will filter, screen, and approved the accuracy and quality of the science videos before they are included in the ScienceHack video search engine.  Users can also submit videos to ScienceHack database.  This website is good for the use of teachers and students, as well as general public to know more about science.

Next time you need not to worry that your son will think that bitten by a spider will spidify himself into SpiderMan.

Radiation therapy (also called x-ray therapy, irradiation, radiotherapy) is the use of ionizing radiation to kill cancer cells and shrink tumors (to relieve symptoms). It destroys cells in the targeted area by damaging their genetic material. The radiation will ionize atoms which make up the DNA chain, damaging them and causing them to die or reproduce more slowly.

Radiation therapy has been in use as a cancer treatment for more than 100 years. The concept of therapeutic radiation was invented by German physicist Wilhelm Conrad Rontgen. With the discovery of computed tomography (CT), physicians are able to directly measure the dose delivered to the patient’s anatomy based on axial tomographical images. With the creation of magnetic resonance imaging (MRI) and positron emission tomography (PET), radiation therapy now have better treatment outcomes and fewer side effects.

Radiation therapy can be used alone or in combination with other cancer treatments such as chemotherapy or surgery.

The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissues.

The amount of radiation absorbed by the tissues is called the radiation dose, which is measured in a unit called ‘gray’(Gy). Different tissues of the body could tolerate various amounts of radiation (measured in centigrays). For example the kidneys can tolerate around 1800 cGy. The total dose of radiation is usually divided into smaller doses (called fractions) that are given daily over a specific time period.

Low-dose palliative treatments usually cause minimal or no side effects. Long-term treatment causes medium and long-term side effects, for example:

1. Fibrosis of the tissues – tissues become less elastic due to diffuse scarring process
2. Hair loss – usually seen in patients who receive radiotherapy to the brain. The radiation could spoil the matrix of the hair follicles thus producing permanent hair loss.
3. Fatigue
4. Cancer and secondary malignancies – this side effect is seen in a very small minority of patients, generally many years after they have received a course of radiation treatment.
5. Shortness of breath – radiation could decrease the levels of the substance called surfactant, which helps keep the air passages open. Low surfactant levels keep the lungs from fully expanding, thus causing shortness of breath or cough. These symptoms are sometimes treated with steroids. Lung fibrosis is also a possible side effect.
6. Digestive tract – radiation to the esophagus, stomach or intestine can cause pain, nausea, vomiting or diarrhea.

Treatment using higher doses causes acute side effects:

1. Damage of the epithelial tissue – for example skin, oral, pharyngeal and bowel mucosa, etc. The skin starts to become pink and sore several weeks into treatment. Although this desquamation is uncomfortable but it usually recovers quickly. There might be temporary soreness and ulceration in the mouth (mucositis) and throat if radiation is given to the head and neck area. Dry mouth and a loss of taste can be caused by radiation damage to the salivary glands and taste buds. Patients might need painkillers and nutritional support.
2. Swelling – as part of the general inflammation.
3. Infertility – the gonads are very sensitive to radiation. They may be unable to produce gametes following direct exposure of radiation.
4. Generalized fatigue.

There are 3 main types of radiotherapy. They are:

1. External radiation therapy – ‘external’ means that the radiation source is outside the body. It is used to treat most types of cancer including cancer of the bladder, brain, breast, cervix, larynx, lung, prostate, and etc. It also includes intraoperative radiation therapy (IORT) which is given during surgery to treat localized cancers that cannot be completely removed or that have a high risk of recurring in nearby tissues. External radiation therapy usually is given on an outpatient basis.
2. Internal radiation therapy / brachytherapy – uses radiation that is placed very close to or inside the tumor. The radiation is usually sealed in a small holder called an implant. Implants can be in the form of thin wires, plastic tubes, catheters, capsules, or seeds. They are put directly into the body. Brachytherapy is commonly used to treat localized prostate cancer, cervical cancer and cancers of the head and neck.
3. Systemic radiation / unsealed radiation therapy – uses radioactive materials which may be taken by mouth or injected into the body. For example, radioactive iodine (iodine-131) which is used to treat thyroid disease like thyrotoxicosis and malignant conditions like papillary thyroid cancer.

Conventional external beam radiotherapy is delivered via 2D beams using linear accelerator machines. Conventional refers to the way the treatment is planned or simulated. The aim of simulation is to accurately target or localize the volume which is to be treated. This technique is well established and reliable. The worry is that some high-dose treatments may be limited by the radiation toxicity capacity of healthy tissues which lay close to the target tumor volume. Some refinement had been done and with the help of computed tomorgraphy (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET), or single photon emission computed tomography (SPECT), a 3-D image of a tumor can be obtained. Using the information from the image, special computer programs design radiation beams that conform to the shape of the tumor. These revolutions allows more accurate placement of radiation beams, thus causing less radiological effects on the nearby healthy tissues.

Intensity-modulated radiation therapy (IMRT) is another type of 3-D conformal radiation therapy that uses radiation beams (usually x-rays) of varying intensities to deliver different doses of radiation to small areas of tissue at the same time. The technology allows the delivery of higher doses or radiation within the tumor and lower doses to nearby healthy tissue. The equipment can be rotated around the patient so that radiation beams can be sent from the best angles. The beams conform as closely as possible to the shape of the tumor.

Certain chemicals can be used to modify a cell’s response to radiation. These are called the radiosensitizers and radioprotectors. Some anticancer drugs, such as 5-flurouracil and cisplatin, make cancer cells more sensitive to radiation therapy. Radioprotectors are used to protect normal (noncancerous) cells from the damage caused by radiation therapy. These agents promote the repair of normal cells that are exposed to radiation, for example Amifostine. It helps to reduce the dry mouth that can occur if the parotid glands receive a large dose of radiation.

Although radiation therapy is not 100% safe and effective for cancer treatment, it could be some cancer patients’ only hope for survival or longer lifespan. Radiation therapy will continue to play a major role in cancer treatment until more effective and safe drugs and treatments are found.

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Imagine if all bankers are engineers…

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Colon cancer has been America’s second biggest killer.  The use of colonoscopy has scared many people from colon cancer screening.  The use of X-ray colon cancer is cheaper and less invasive than the colonoscopy.  The success rate of the new ‘virtual colonoscopy’ a.k.a. computed tomogrpahic (CT) colonography in detecting colon cancers or abnormal growth, which are detected by normal colonoscopy, is as high as 90%.  However misinterpretation of the X-ray can lead to the spotting of polyps, therefore follow-up results are needed to confirm the analysis.  There are other drawbacks of this new technology in detecting colon cancer which need to be further investigated and improved.

(news [journal])

Your index and ring fingers length can affect your voluntary exercise desire.  According to a recently published paper, people who have higher index:ring finger ratios are more willing to exercise.  Generally women have higher ratio than men.  The study revealed a strong correlation between the digit length and levels of prenatal stress hormones as well, which ultimately affects one’s personality.  This research reminds me of the Chinese palmistry, which use the lines on the hand as well as the shape of the hand, to study one’s life, behaviour, personality, etc.

Reference:

Yan et al. Selective Breeding for a Behavioral Trait Changes Digit Ratio. PLoS ONE, 2008; 3 (9): e3216

Since 30 August, this blogs’ authors experienced the problem of login to write new posts.  All users can’t login to the wordpress (this blog is wordpress platform), and the problem is not solved after requesting new passwords.  After series of investigation and googling, it was found that the problem was due to one of the plugin, namely kqf, which was used to aggregate the news feed for this blog.  The plugin was removed, and similar plugin is still in search to replace it.  If you are experiencing after login to wordpress and it redirects you back to wp-login.php page, please try to remove some of your plugins.

I just bought a new iPod nano 4th generation (product) red.  I sincerely wish that iPod has a bluetooth function so that songs can be transferred easily between iPods.  I love my new iPod nano.