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1 SCIENCE FOCUS Issue 013, 2018 Penicillin: Beyond Fleming Love Thy Enemy Parasite Makes Rats Attracted to Cats The Chemical Magic of Hand Warmers Applications of Time Reversal Interview with Prof. Mathias Fink Q&A with HKUST Scientists

2 Contents Science Focus Issue 013, 2018 What s Happening in Hong Kong? 桗㳭䢏ㄾ㯹 Amusing World of Science 䢏 屡ᵉ HK SciFest 2018 榀㸖䦸 䮧 1 "SOPHIE - IVE's Solar Cars Driving the Future" Special Exhibition 623+,(,9( 䙫 晤僤庱樬 㜑Ὥ 栳ⰼ妤 An Adventure to the Amazon ẅ榓恃㭞暑 Science in History 㓒㒣䢏 Penicillin: Beyond Fleming 䛋Ⱓ奦㝾䙫 勘暫 2 Love Thy Enemy Parasite Makes Rats Attracted to Cats 㕜ạ ă 䔆埙ị俨漇墒屺暢 12 The Chemical Magic of Hand Warmers 㙽 䙫 欻㲼 16 Nanotechnology... At a Store Near You 䳴䱚 堺 ü Ⱈ 庒恱 18 Rising from the Ashes: Ecological Succession after Volcanic Eruption 㵛䁒憴䔆Ɲ䁒ⱘ䇭䙣 䙫䔆ㄲ㻻㛦 20 Who s Who? 䢏 Ⲧᵸ Science Today ᶈ㒣䢏 Lazy Ants Are Far from Useless ḍ杅㯒䄈岉䍢䙫 プ垅埢 4 The Mystery of the Universe - Negative Mass Ḳ嫵 ă 岇峑憶 6 CRISPR: Gene Editing Made Simple &5,635Ɲ䰈 弖 8 How Underwater Waves May Solve an Aviation Mystery 㜂姊㱡刑䩡 Ḳ嫵䙫偙憴 㳉 10 Applications of Time Reversal Interview with Prof. Mathias Fink 㘩敺 㻻䙫ㆰ䔏 ă 娑 0DWKLDV )LQN 㕀 22 Q&A with HKUST Scientists 䦸 䦸 䙫 凮䬻 24 Acknowledgements 䄷 殲姛 Message from the Editor-in-Chief Ḣ 婘媅 Dear Readers, 妑 䙫孧俬Ɲ Welcome to the latest issue of Science Focus! After serving as a scientific advisor of this magazine in the last two years, this is the first time I write as the Editor-in-Chief. As usual, we hope to bring you interesting scientific stories that connect closely with daily lives. Have you used hand warmers in the past winter? Do you know the chemistry behind these heat-emitting pouches? The import of drugs to treat rare genetic diseases was widely covered in the local news. Do you know gene editing may provide alternative treatment options in the future? 㭈徵斘孧㛧㖗 㜆䙫ˣ䦸姧ˤƄ 怵 ⅐ Əㇸ 䛛㒻䕝怀㜓 曃婳䙫䦸 桎 Ə怀㘖ㇸ䬓 㬈ỌḢ 䙫庒Ụ⑳ 奲杉 㗉 ƏㇸῸ 㜂 䵍 ῲ凮䔆㴢ざざ䛟旃䙫㛰嶊䦸 㔬 Ṳ 怵 䙫 㛰䔏怵㙽 Ƣ 䟌怺怀Ẃ䙣䆘 傳 䙫 䏭 Ƣ㛧徸Ọ怙 嗌䉐㲢䘩似奲恡ₚ䖥䖬䙫㖗 偅墒 䮮 Ə 㘖 䟌怺 弖㜑Ὥ㛰㩆㛪 Ọㇷ䂡 㲢䘩㖠㠯Ƣ Looking forward, we strive to increase our digital presence by posting in our website and on social media. Please leave us your feedback and suggestions so that Science Focus can better serve you. And don t forget our writing competition. You may submit your articles by at sciencefocus@ust.hk for a chance to have them published in future issues. Lastly, I would like to thank Professor Yung Hou Wong for laying a solid foundation for Science Focus. Our staff and student editors will continue to work closely together for many issues to come. ⰼ㜂 ὭƏㇸῸ㛪凛 䶙 ⷌὃƏḍ㖣ㇸῸ䙫䶙䫀 䤥ẋ 檻 䙣Ἧ㖗㵯ざ 㭈徵 Ὸ ヶ奲 字Ə孺ˣ䦸姧ˤ Ọ㛛怙 㭌 媲 奨 姿ㇸῸ䙫 ὃ㮻峤ə Ọ ὃ 曢惜 凚 VFLHQFHIRFXV#XVW KNƏḍ㛰㩆㛪䍙 䙢㖣㜑Ὥ䙫ˣ䦸姧ˤ Ḕ 㛧 Əㇸペㄆ嬄䍲㮞 㕀 䂡ˣ䦸姧ˤ ṭ䩐 䣵Ə俳ㇸ Ὸ䙫 晱 䔆 ẍ㛪䂡ˣ䦸姧ˤ乣乳䶱 ὃ Yours faithfully, Prof. Ho Yi Mak Editor-in-Chief Scientific Advisors 䢏 朥 Dr. Jason Chan 晚戅⁸ Prof. Karen Chan 晚㼻䑃㕀 Prof. Simon Chan 晚曙㕀 Prof. Tom Cheung 㚰㝘㕀 Dr. Ice Ko 檿デ Prof. Pak Wo Leung 㡨 ⑳㕀 Copyright 2018 HKUST Ḣ 溌㙎 㕀 㕓 Student Editorial Board 䏝䲦 Editor-in-Chief Ḣ 弖 Prof. Ho Yi Mak 浣㔥 㐗 Associate Editor 弖 Prof. Yung Hou Wong 䉉㩵 㐗 Managing Editors 两 弖 Janice Wong 䉉㧡㧡 Mandy Wong 溪㔶 sciencefocus@ust.hk Editors 弖 Long Him Cheung 㗕姗 David Iu 奞氞 Henry Lau ⅇᶣ嶐 Melody Ma 桪 Twinkle Poon 㸖㔲 Chantelle Sullivan 哅䖆 Reporter 姿俬 Teresa Fan 㣈慖 Graphic Designers 娔姯 Steve Min Kyu Park Tommy Wong 涁㝑姗 Lynn Zhang 㰵䋱 Homepage:

3 WHAT S HAPPENING IN HONG KONG? Let Your Love for Science Flourish! The cold winter has passed, and it s time for you to go out and have some fun in the following selected events with your family and friends in this spring! HK SciFest 2018 The annual HK SciFest is back again! A wide range of over 160 scientific activities are available during the event, including science demonstrations, fun experiment classes, science drama shows, film appreciation, visits and guided tours, etc. You will surely enjoy the SciFest while enhancing your understanding of science through these interesting activities! Date: Now 25 April 2018 Venue: Hong Kong Science Museum Website: scifest2018/eintroduction.php SOPHIE IVE s Solar Cars Driving the Future Special Exhibition Ever wonder how solar energy works in green cars? The locally developed solar car series SOPHIE is now on display. You will get to see the fourth generation of this series, SOPHIE IV, and find out more about solar cars and its related technologies through this interactive exhibition! Date: Now 12 September 2018 Venue: 2/F Exhibition Hall, Hong Kong Science Museum An Adventure to the Amazon Wonder what you will find in the mysterious Amazon? The Hong Kong Space Museum is running an OMNIMAX Show Amazon Adventure until 31 August Let s join an adventure there now! For details, please visit scifest2018/introduction.php 1

4 Alexander Fleming is a household name synonymous to the discoverer of Penicillin, one of the most widely used antibiotic agents that has saved countless people. Nevertheless, unbeknownst to many people is that many other scientists, with the key ones being Howard Florey, Ernst Chain and Norman Heatley, also made significant contributions towards the success of the discovery and production of penicillin. It all started in September 1928, when Fleming left his laboratory for a few days without cleaning up the plates on which he grew some samples of bacteria. Upon his return, he noticed a mold growing on one of the plates. However, there was a ring free of bacteria surrounding it. He postulated that the mold which he then found to be Penicillium notatum might contain a substance that killed bacteria, and named the substance penicillin. However, P. notatum was difficult to grow, and introducing it to the human body orally proved to be ineffective. The idea of massproducing penicillin as an antibiotic seemed too difficult and expensive to achieve. Now that Fleming has provided the scientific community with the first clue in solving the puzzle of antibiotic extraction and production, further problems had to be solved by other scientists. In 1938, Florey and Chain, two scientists from Oxford University, stumbled across Fleming s papers on penicillin and decided to research on improving antibiotic extraction. One of the trainees of Chain, Norman Heatley, was able to produce penicillin of a much higher purity with a method called back-extraction. The method began with mixing an acidified mold solution with amyl acetate, which left behind some unwanted impurities. Next, the solution was introduced back into water via a countercurrent system [1]. Upon freeze-drying of the mixture, a 1% pure penicillin powder was obtained. With this method, the team had enough penicillin to test on mice that were injected with Streptococcus bacteria. The promising results showed that the mice recovered after receiving a dose of penicillin [2]. Penicillin: Beyond Fleming By Chantelle Sullivan

5 By 1941, Britain was suffering immensely from damages done by the Second World War. Resources for scientific research were depleted, and Florey was left with no choice but to make his way to the United States to further his research. A team was assembled in Peoria, Illinois, which Heatley was also a part of. A growth medium based on liquid extract was used to grow the mold, and gave a tenfold increase in yield [1]. However, the team was determined to find another strain of bacteria that was capable of producing a higher amount of penicillin, to solve the problem of mass-producing the antibiotic. In 1943, the team was still hard at work in finding a new strain. A new mold, Penicillium chrysogenum, was found in cantaloupe. It produced penicillin 200 times more than Fleming s strain did. Additional refining gave rise to a further five-fold increase in yield [1]. The mass production of penicillin was in near success when Heatley surprised the team with his innovation by mechanizing his back-extraction method by using whatever materials he could find, including drink bottles and milk churns, to speed up the production process and reduce manual labor. Furthermore, another problem was tackled when glyceryl monoricinolate, an antifoaming agent, was added to the mixtures to prevent severe foaming when sterile air was bubbled, to provide the mold with fresh air for penicillin production [1]. At this point, penicillin could be produced in quantities large enough to be packaged for soldiers of the war, preventing further deaths caused by bacterial infections. The antibiotic was only made available to the general public in 1945, upon the end of the Second World War. Following their pivotal achievement, other scientists combined efforts into creating different kinds of antibiotics that targeted other bacteria, some of which could not be killed by penicillin. While Heatley unfortunately did not receive the recognition he deserved for his key contribution to the development of the antibiotic, Florey and Chain shared the Nobel Prize for Medicine with Alexander Fleming in 1945 [3], for their joint efforts on their work on penicillin, and for paving the way for future studies on antibiotics. Their groundbreaking discovery of penicillin and subsequent invention of antibiotics proved to be a revolutionary turning point in medical science, changing the way in which medicine was practiced, and undoubtedly saving the lives of millions. References [1] American Chemical Society. Discovery and Development of Penicillin. American Chemical Society International Historic Chemical Landmarks. Retrieved from [2] Bédoyère, G. The Discovery of Penicillin. London: Evan Brothers Limited, [3] Rooney, Anne. The Story of Medicine. London: Arcturus Publishing Limited,

6 Ants are arguably the world s most productive organisms. However, are all ants as relentlessly hardworking as they apparently are? Studies have shown that typically over 50% of workers in a social insect colony (for example, ants, honey bees, wasps, termites) are inactive at any one time [1]. Daniel Charbonneau and Anna Dornhaus, entomologists of the University of Arizona, investigated a group of lazy members of the ant species Temnothorax rugatulus. When tracking the behavior of 250 ants, the researchers found that 40% of them were inactive consistently [1]. In another study with biologist Takao Sasaki of the University of Oxford, the scientists collected 20 colonies of Temnothorax rugatulus [1]. They painted the ants with special color codes so that they could track the behavior of each individual over time with an HD camera. The ants were observed and classified into three broad categories according to the tasks they performed: active, inactive and undifferentiated. The active class refers to ants performing tasks such as building, foraging, eating and grooming, while inactive ants are those that are completely immobile and not engaged in any of the active tasks mentioned before. Ants are undifferentiated when they are mobile inside the nest and not engaged in any active task. The scientists then removed some of the workers to observe how the colonies were affected. Each colony received either of these treatments: removal of the 20% most active workers, that of the 20% most inactive, and that of 20% randomly picked workers. Overall, the activity of the affected colonies was reestablished, with no significant difference between preremoval and post-removal stages. The colonies seemed to compensate the loss of workers after the most active ones were removed. Within two weeks of removal, some of the inactive ants became the most active workers. On the other hand, upon removal of the inactive workers, the colonies did not seem to replace them. This observation supports the hypothesis of reserve labor, one of the most common explanations for social insect laziness. It is suggested that inactive ants can serve as standbys to replace active workers when necessary, allowing a colony to respond quickly and flexibly to changes in labor. The reserve labor force could be crucial to a colony s survival in case of emergency, such as being attacked. Apart from being reserve labor, other potential functions of lazy workers have been proposed, such as acting as food storages or energy reserves for production. It is also possible that the seemingly inactive insects are indeed performing crucial tasks that have not been observed and identified yet. Lazy Ants Are Far From Useless By Twinkle Poon

7 The research team speculated that age could be one of the determining factors of reserve ant workers. For example, it makes sense for young workers to be inactive as they are the most vulnerable members of the colony [2]. Despite the relatively large proportion of inactive individuals in a colony, ants remain one of nature s most successful organisms. The laziness of the ants might play an important role in maintaining long-term sustainability in the complex insect society. Indeed, the studies show that there is still plenty for us to learn about insects laziness. References [1] Charbonneau, D., Sasaki, T., Dornhaus, A. Who needs lazy workers? Inactive workers act as a reserve labor force replacing active workers, but inactive workers are not replaced when they are removed. PLoS ONE 12(9): e (2017). org/ /journal.pone /j [2] Stolte, D. Lazy Ants Make Themselves Useful in Unexpected Ways. UANews (2017). Retrieved from lazy-ants-make-themselves-useful-unexpected-ways 5

8 Mass seems to be something trivial for all of us it is obvious that a heavier object should have a greater mass. Nonetheless, the concept of mass was introduced so late in the 16th century by Sir Isaac Newton in his famous Newton s Law of motion. Before Newton, although people had the idea of heaviness, they did not come up with a systematic way to define it. People are often confused with the terms weight and mass, which are two completely different ideas. Weight refers to the gravitational force acting on an object, yet mass is a measure of the tendency for an object to remain in uniform motion. An alternative way to describe mass is that an object with greater mass requires a greater force to accelerate. From our daily experience, if we push an object, it should move away from us. This seems to be a stone-cold fact. However, it is not always the case it is only true for positive mass. All the objects we normally encounter have positive mass, that is, the object would accelerate in the same direction as the applied force. It is counterintuitive to imagine an object accelerating towards you when you push it away. Nevertheless, like how matter can have a positive or negative charge, there is no physical constraint preventing the existence of negative mass. Although negative mass is absent from our daily lives, negative mass may have an important role in astrophysics and cosmology [1]. Recently, led by Peter Engels, professor of physics and astronomy from Washington State University, researchers have created a fluid composed of rubidium atoms which exhibit the property of negative mass at extremely low temperatures. Using a technique called laser cooling, the rubidium atoms are slowed down and trapped by lasers until they are cooled to a temperature near absolute zero. At such a low temperature, the particles obey the principles of quantum mechanics, which govern the interaction between particles under low energy regime. The fluid thus forms a state of Bose-Einstein condensate, which refers to an ultra-cooled dilute fluid, where most particles are in their ground state as the energy is too low for any excitation [2]. It is as if the lasers-trapped atoms are experiencing great pressure once the laser trap is disturbed, the atoms may rush out. Making use of this property, the researchers shot a second set of lasers to shake the atoms. Under such conditions, the rubidium atoms tended to rush out in the opposite direction as the applied force, showing traits of negative mass [1]. Negative mass seems to be a weird concept, yet it is closely related to astrophysics and cosmology. In theory, it is expected to have a kind of substance called dark energy, which exhibits repulsive gravitational force, and plays an important role in the expanding universe. It is predicted that if dark energy really exists, it should have negative mass. Up till now, there is no experiment available to study the analogous physics related to dark energy. Nevertheless, with the newly developed rubidium fluid that shows traits of negative mass, scientists may be on the brink of a breakthrough for the study of fundamental forces, as well as cosmological phenomena such as black holes [1]. By Long Him Cheung

9 If you kick a ball with negative mass to the right, the ball would fly to the left instead. References [1] Sorensen, E. Physicists create negative mass. Phys.org (2017). Retrieved from [2] MacDonald, F. Physicists Say They ve Created a Fluid With Negative Mass. ScienceAlert (2017). Retrieved from 7

10 Have you heard of Golden Rice? Do you know it has a higher nutritional value than your regular rice? The key to its success lies in gene editing. DNA is the genetic blueprint of living organisms. Specifically, DNA harbors instructions on how to form proteins, the fundamental building block in life, in units called genes. Scientists are rewriting the language of life through gene editing. In this process, the genes of an organism are altered to produce useful products like Golden Rice. Gene editing may also be used to cure diseases in the not too distant future. One of the most exciting breakthroughs in gene editing was its application in curing HIV infections, a condition previously thought to be incurable. Researchers at Temple University have succeeded in using CRISPR Cas9 to remove the HIV-associated DNA sequences from the genome of three different mice models [1]. This marked the first time when all traces of HIV were successfully removed from an animal model at different stages of the disease a promising step towards the dream of gene therapy. So how did they do it? CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. CRISPR is used in nature by bacteria to protect themselves against viral infections - by chopping up the DNA of the invading virus. Scientists have been able to modify this process for gene editing in plants and animals. CRISPR Cas9 gene editing system consists of three main components: a Guide RNA (grna), the Cas9 protein and a donor DNA. The grna has scaffolding and targeting parts. The scaffolding part associates with Cas9 protein to form a complex. There are four bases in DNA, namely A, T, C and G. In a process called complementary base pairing, DNA bases pair up with each other, namely A with T, and G with C. The targeting part of Gene Editing Made Simple

11 the grna is designed to bind uniquely to the target DNA sequence. The grna is custom-made and designed to be complementary to the target DNA sequence researchers wish to change. Cas9 is an endonuclease. It is similar to restriction enzymes that act as gene scissors to cut the DNA at specified points. Lastly, the donor DNA contains the desired modifications to be introduced to the target cell. These three ingredients are delivered to the target cell where they can interact with the host genome to facilitate gene-editing. There are three steps in CRISPR Cas9 gene editing: binding, cutting and repairing [2]. Firstly, the binding of the grna to the target DNA sequence occurs through complementary base pairing [2] [3]. One can imagine the grna as a tow truck, pulling Cas9 to the target site. Then, once the grna is bound to the DNA, the Cas9 protein, the gene scissors, starts to cut the DNA at an exact position so the entire DNA molecule is split into two [2] [3]. The broken DNA can then be repaired at a certain frequency by using the donor DNA as a repair template [2] [3]. Upon the completion of all three steps, the sequence specified in the donor DNA is incorporated into the host genome. CRISPR is hailed as a revolutionary technology due to its unparalleled precision and ability to simultaneously edit different spots in the genome. However, it is not as simple as it seems. It has taken researchers years to achieve the feat. The system has yet to be perfected; complications can easily arise in any of the three steps, causing unwanted harmful mutations. Scientists are still exploring safer ways to apply the technology. Other than technical challenges, there are many ethical questions concerning gene editing in general, such as whether the purpose of application contradicts ethical norms. These ethical and technical issues need to be resolved before this technology can be broadly applied. Yet scientists are confident that, like many technologies, CRISPR will bring a better future. By Henry Lau References [1] Park, A. HIV Genes Have Been Cut Out of Live Animals Using CRISPR. Time (2016). Retrieved from [2] Cortez, C. CRISPR 101: Homology Directed Repair. Addgene (2015). Retrieved from homology-directed-repair [3] Cavanagh, P., Garrity A. CRISPR Mechanism. Retrieved from 9

12 How By Melody Ma Waves May Solve an Aviation Mystery Have you ever thrown pebbles into the sea? Have you ever imagined that you can trace the time and location that they fall into the ocean? It seems impossible; however, it may be an easy task from now on. Researchers from Cardiff University have just developed a method to find out the precise time and location that objects fall into the sea by analyzing the underwater sound waves emitted when an object hits the surface of the ocean. Termed acoustic gravity waves, these sound waves are generated by a sudden change in water pressure as objects hit the ocean surface. In other words, they can be caused by anything from submarines, earthquakes and landslides, to falling meteorites or other objects impacting the sea surface, as the researchers explain. The waves occur naturally and travel at the speed of sound across the deep ocean, thousands of meters beneath the surface. They can also travel very long distances of up to hundreds of kilometers [1] [2]. Acoustic gravity waves can be picked up by hydrophones, which are underwater microphones. The researchers proposed technique is not to be confused with sonar. Short for Sound Navigation and Ranging, sonar detects objects in the ocean by emitting pulses. Instead of measuring acoustic gravity waves, the technique measures acoustic frequencies varying from infrasonic to ultrasonic. In their study, the research team started off by using a water tank. They dropped 18 spheres from different heights and locations onto the water surface, and measured the emitted acoustic gravity waves using hydrophones [1] [2]. The team found that the sound wave profile for each impact seemed similar, consisting of three parts. The first part seems to be the initial impact itself, followed by the second part as the object enters the water, it traps some air, which eventually rises back to the surface. The last part seems to be secondary waves that impact the bottom of the tank, before reflecting back up, explains Usama Kadri, one of the lead authors of the study [3]. As the waves travel through the ocean, they disperse because higher frequency sound waves travel more quickly than waves at lower frequency. Observing the dispersion of the waves thus allows researchers to estimate the distance the waves have travelled, which could help them locate the origin location. The team also analyzed data from the hydrophones of the Comprehensive Nuclear-Test- Ban Treaty Organization (CTBTO) off the coast of Western Australia. The microphones are used to detect underwater nuclear tests, but they can also pick up acoustic gravity wave signals. The data collected allowed the team to determine the time and location of earthquakes in the Indian Ocean with satisfactory accuracy (with errors of around km) [1]. The research was originally motivated by the scientists hope to gain more knowledge about the *MH370 (Malaysian Airlines Flight MH370) flight incident. Using the method developed, the team

13 succeeded in locating two points around the time of the aircraft s disappearance. However, the researchers could not be certain that the discovery had any real association with the plane. Just like in a busy restaurant, it gets more and more difficult to pick up individual voices as the noise in the room gets louder, they write in the study. That said, the team have passed all the information acquired to the authorities [1]. While it remains uncertain whether the method could offer assistance regarding the MH370 incident, researchers believe that the technique can open up a wide range of possible applications. It can be used to locate items that might have fallen into the ocean, such as meteorites, satellites and even debris of aircrafts. It can also be used to locate underwater explosions s and the epicenter of earthquakes [1]. * Malaysian Airlines Flight MH370, carrying 239 people, disappeared on 8 March 2014 when it was en route to Beijing from Kuala Lumpar. Despite extensive searches of the Indian Ocean floor, the main wreckage has not been found. This incident has become one of the biggest mysteries in aviation history. References [1] Underwater sound waves help scientists locate ocean impacts. Cardiff University News (2017). Retrieved from news/view/ underwater-sound-waves-help-scientists-locate-ocean-impacts [2] Kadri, U., Crivelli, D., Parsons, W., Colbourne, B., Ryan, A. Rewinding the waves: tracking underwater signals to their source. Scientific Reports (2017). [3] Chu, J. Ocean sound waves may reveal location of incoming objects. MIT News (2017). Retrieved from 11

14 What would you do when a ravenous lion approaches, threatening to devour you whole? Naturally, you flee, fearing for your life. Preys have evolved to avoid their predators. And hence, one would expect a rat to flee upon smelling the scent of cats the scent of imminent doom. This avoidance behavior is, however, only the case for healthy rats. Rats infected by the parasite Toxoplasma gondii are attracted to cat odors. By manipulating specific neural circuits in the rat brain, the parasite renders a rat incapable of perceiving fear in the presences of cat odors, and activate pathways that cause the rat to fall in love with cats, making it brave enough to chase after the scent of cats. T. gondii is a single-celled pathogenic protozoan capable of infecting virtually all warm-blooded animals and causes a disease called toxoplasmosis [1]. Once the host is infected, the protozoan divides rapidly and spread throughout the body, especially to muscles and brain, where they become latent intracellular cysts. These intracellular cysts protect the protozoan from the host immune system and antibiotics. In humans, it has been estimated that 30-50% of the global population has been exposed to and may be chronically infected with T. gondii. However, this infection has no readily observable symptoms in healthy adult humans. What makes T. gondii unique is its reproductive cycle sexual reproduction must take place in a cat s intestine. After entering the cells that line the cat s small intestine, the parasites undergo sexual development and produce millions of zygotecontaining cysts. Each cyst is capable of surviving and spreading for months, once shed through cat feces. The most common pathway for T. gondii to enter the cat intestine is by accidental ingestion of cysts. If you were a T. gondii cell, how would you smuggle yourself there? The best way is perhaps for you to hide inside their favorite meal rats. This brings us back to the curious case of the fearless rats. By changing the behaviors of infected rodents, T. gondii increases their chances of being preyed upon by cats, and in turn raising the probability of ingesting the cysts inside the

15 ϯዲϡ ș ġ Ӡᚪ ցᄂജᓤ כ є 䕝 暢棺㥜䙫䌬 杇徸Ə 僬奨 Ə 㛪 Ἴ 7 JRQGLL 䙫䍏䉠Ḳ嘼 㖣⅝丨㭽 㜆 ă 㛰 丨㭽 柯 ㆰƢ凑䄝 㛪䂡凑ⷘ䙫 俳忪嶸 䍜䉐ⷙ㻻 凚㛰忪 屺䙫兟准ⅎ䙣䔆 䔆埙态怵ㄆ㞺屺暢 兟䙫䴗僅Ə怙堳 恦 棆俬䙫僤 Ə 㭋 㛪柷㜆䕝俨漇 屺䙫㰊 ă 䔆㭽䙣ⰼ 䔉䔆㕟Ọ䙥吓姯䙫 䲥 僅 㮶ῲ 僅忶怵屺 怲怣徸䙫㰊 Əᾦ㛪䪲 忪嶸 暢䙫 㲫䉐 Ə僤 檻 䔆 ⑳㓛㕊㕟ῲ㛯 ヶ ㄆ 㞺 僅㘖7 JRQGLL 怙 屺暢兟准㛧㙕怴䙫忻 㞃 㘖 䄝俳怀䨕庙恦堳䂡 㛪 䙫俨漇庒 䙣䔆 䕝俨漇 ㄆ㞺 䂡7R[RSODVPD JRQGLL 䙫 䔆埙Ə䉇Ὸ 俳㛪 㭈屺 ῲ7 JRQGLL 䴗僅Ə 㛪 Ἴ 怲凑ⷘ 悊壈Ƣ㛧 䙫㖠㲼 ㇽ娘Ⱈ㘖庙 䉇Ὸ㛧 䙫俨漇Ḕ 䙫㰊 䔆埙忶怵㒴 俨漇䉠 䙫䥅䵺 巖Əị俨漇 僤 孺ㇸῸⅴ媮媮䄈䔶俨漇 7 JRQGLL 忶怵㔠孱 ㄆ㞺潎漹 ㄆ 凑ⷘ 屺㰊 䙫 Əὦ䉇Ὸ 屺Əḍ 㕉 忤 䉐䙫堳䂡Ə 䉇Ὸ墒屺暢 棆䙫㩆㛪Ə 俳 檿屺暢 䉇Ὸ䙫㰊 7 JRQGLL 㘖 䨕 凛䖬䙫 䴗僅 埙Ə僤 ㄆ㞺㈧㛰㺒 堧 䉐Ə 凛ἶ堧 埙䖬 Ḣ 㗍 ㄆ㞺Ə 埙㛪 怆 䂯 㓛㕊凚 庒Ə䉠 㘖偳偰 免惏Ə䙣ⰼㇷ㽂 䴗僅 ⅎ䙫 僅Ə俳 僅㛪䂡 埙 ᾂ Ḣℴ䖒䳢䵘 䔆 䴇䙫ῄ孞 䏥 姯㛰䙥 Ḳ 凚ṻ 䙫 䏪ạ ⷙ㛄朙 7 JRQGLL Ḳ Ə䔁凚 僤ⷙ 憴ㄆ㞺 怵Ə 䙫ㇷ ạ 㔝 僅䙫 僤 Ụ 䙫䟻䩝桖䤡Ə7 JRQGLL 㒴 俨 漇凮䔆ῘὭ 㖣屺暢㴢 ㇽ䖼巈䙫䄍ㅕƏὦ䉇Ὸ歖厤 怀 Ẃ䖼巈㈧ ῲ 俨漇凑庒䙫㰊 㖗殕䨢匰 屺 暢 㰊 䬰 䨕䍏䉠㰊 䙫忞 ⅎə ㄆ㞺䙫俨漇䉠 㕊䙣吾屺暢㰊 䙫 Ə䉇Ὸ㛪㮻㜑 ㄆ㞺漇暢廪 嵗 怵怀Ẃ Ə䛟 㜑 ㄆ㞺漇暢 㗵桖㛪恦敲 ὦ ㄆ㞺ẍ㱹㛰㗵桖䖬䙌 (1(0< z $775$&7(' 72 &$76 By David Iu 奞氞 13

16 rodents. In a 2000 study, T. gondii was shown to manipulate the rats inherent perception of anxiety in the presence of cat activity or marks, making them imprudently attracted to these marks. By designing a labyrinth of bricks containing unique odors including the rat s own smell, fresh straw, cat odor, and rabbit odor, a non-trivial preference for cat-scented areas was found. Toxoplasma-infected rats traverse the labyrinth to these areas more often than non-infected rats which demonstrated marked avoidance [2]. Such behavioral alterations may stem from an imbalance of neurotransmitters in a region of the brain called the amygdala. The amygdala is responsible for memory processing, decision making, and emotional reactions. One of the consequences of disrupted regulation of amygdala function is abnormal, erratic behaviors. This is one brilliant example of how smart adaptations like this could help with survival and proliferation. In fact, changing one s hosts behaviors to enhance species competitiveness is not strictly Toxoplasma s specialty. For example, certain species of nematomorph hairworm develop parasitically in grasshoppers and crickets as larvae. Once grown, the larva manipulates its host into jumping into water, where the host will likely drown and the parasite can return to its usual aquatic habitat. When learning about evolution we might often fall into the trap of viewing it through rose-tinted glass where nature seemed elegant and noble, with smart features emerging with generations of progress. Nevertheless, we should be reminded that nature can be a bleak and unforgiving place, and organisms could go to extreme ends to survive. References [1] Parasites Toxoplasmosis (Toxoplasma infection). Centers for Disease Control and Prevention (2015). Retrieved from gov/parasites/toxoplasmosis/biology.html [2] Berdoy, M., Webster, J. P., & Macdonald, D. W. Fatal attraction in rats infected with Toxoplasma gondii (2000). Proceedings of the Royal Society B: Biological Sciences, 267(1452),

17 怀㨊䙫堳䂡㔠孱 僤㘖 䂡免惏㜶Ẩ㠟Ḕ䙫䥅䵺ₚ 䉐 峑 塈 㜶Ẩ㠟岇岓姿 嘼䏭 ὃ 㱡 ガ ㆰƏ 㭋㜶Ẩ㠟 僤 㓥䙫 㞃Ḳ Ⱈ㘖 堳䂡 怀䕗 䙫俨漇堳䂡⅝ 㘖㛰 䉇Ὸ庒 䔆䉐䙫䔆 ⑳丨㭽 Ṳ Ə㔠孱 Ḣ堳䂡 䉐䨕䫝䈔 ḍ杅 㘖 7R[RSODVPD 䙫䉠敞 ὲ 㞷Ẃ憸 埙 䨕䙫 埙㛪 䔆㖣 匰圉 垲垧ḔƏ䕝䉇Ὸ敞ㇷ Ə 埙㛪㒴 Ḣὦ䉇巚怙㰛 Ḕ㷠㭢Ə 俳 䉇Ὸ䆆ば䙫㰛Ḕ㣙ざ 䕝ㇸῸ 侹怙 㘩Ə 僤 䳻 Ọ䂡 凑䄝 㘖ℑ暬 俳檿岛Ə 䨕䔆䉐 ㆰ ỊỊ䙫䙣ⰼ俳怙 Ẃ䉠 ⅝ ㇸῸẍㆰ婙 慹凑ⷘƏ 凑䄝 Ọ㘖 ῲ匹㶣俳䄈ガ䙫 㖠Ə䔆䉐䂡ṭ䔆 㛪 ッ The amygdala is a major component of the brain s fear circuit. Image credit: NIH Medical Arts. CC BY 4.0 pbio g pbio g001&req=4 ϯዲϡ ș ġ ġġġġġġġġġġġġġġġ Ӡᚪ ցᄂġ ġġġġġġġġġġġġġġġജᓤ כ є 15

18 The Chemical Magic During freezing winter days, a pocketsized hand warmer can be a life saver. You probably have a hand warmer to get yourself through winter. Have you ever wondered why a tiny pouch can generate so much heat without fire or electricity? The answer lies in some simple chemistry principles. Popular hand warmers rely on heat-releasing chemical reactions, also known as exothermic reactions. There are two common types of hand warmers, one producing heat by the oxidation of a metal and the other by the crystallization of a salt. Oxidation-based hand warmer packs usually contain iron powder, water, salt, activated carbon and vermiculite [1]. A hand warmer starts to heat up once it is taken out of the sealed package and is exposed to air. Iron is oxidized, forming rust (iron oxide/hydroxide) and releasing heat. This process is indeed the same as the rusting of iron that you may observe in daily life. Iron rusting under normal circumstances, however, takes place at a much slower pace so the heat released is rarely noticeable. Why is iron in the form of very fine powder in the hand warmer? Iron powder is used instead of a chunk of iron as the large surface area of the fine powder greatly speeds up the oxidation reaction. Chloride ions in salt act as catalysts to further accelerate the oxidation. In the presence of Chloride ions, the formation of a more porous [2]. While activated carbon facilitates the dispersion of heat and helps to bring oxygen to the iron particles through gas adsorption. Vermiculite is an inert lightweight mineral that maintains an optimal moisture level for rusting to occur. Generally speaking, the performance of such a hand warmer depends largely on its size and air circulation. The number and size of breathable holes on the package may have a role to play too. In general, 1 gram of iron can release 1.7 kilocalories of heat. An iron powder warmer can get quite hot so direct contact with the skin should be avoided. Reducing contact with air may help slow down the oxidation, so if you want to save a still-warm iron hand warmer for use later on, you may try sealing it with an air-tight zipper bag, slightly lengthening its lifespan [3]. If you want the warmer to be hotter, however, you can improve air circulation in the pouch of iron powder by shaking it, thus speeding up the oxidation. Whatever you do, once the oxidation is completed, the warmer stops heating and it cannot be reused. Crystallization-based hand warmers, on the other hand, can be used over and over again, which is why some people consider them a more environmental-friendly option than their counterparts. Such a hand warmer is usually a sealed bag of chemicals in the form of a supersaturated sodium acetate solution with a small metal chip inside. Supersaturation means that the solvent contains more of the dissolved substance (solute) than it can normally hold at the given temperature. When you flex the metal chip, nucleation occurs at the chip surface and the solution crystallizes, releasing heat. To reuse the warmer, simply heat it in hot water and dissolve the crystals again. Crystallization-based warmers are easy to use and recharge, but their heating time is usually shorter than oxidation-based ones. Both types of hand warmers offer convenient, affordable solution to keeping oneself comfortable in cold weather. These small pouches of warmth are just another perfect example of the indispensable part chemistry plays in every aspect of our day-to-day life.

19 of Hand Warmers By Twinkle Poon References [1] Wang, L. What s inside disposable hand warmers? Chemical & Engineering News (2010). Retrieved from [2] Song, Y., et al., Sci. Rep. 2017, 7, [1]6865. Effects of chloride ions on corrosion of ductile iron and carbon steel in soil environments DOI: /s [3] Heid, M. One simple trick makes hand warmers last a lot longer. Appalachian Mountain Club. Retrieved from 17

20 UV SPF 30 UV SPF 30 SPF 30 SPF 30 UV SPF 50 SPF 50 SPF 30 SPF 30 UV UV UV UV UV UV Nanotechnology... At a Store Near You By Long Him Cheung In our daily life, we would sometimes encounter products that claim to be powered by nanotechnology, such as sunglasses or body armor. However, do you understand what nanotechnology is? Nanotechnology refers to the understanding and manipulation of matter of mere nanometers, where 1 nm is equivalent to 10-9 m. You can imagine that one nanometer is about a hundred thousandth of the diameter of a human hair, or comparable to the size of an atom. At the nanoscale, some atoms or molecules are found to perform counterintuitively due to quantum effects, which allow the development of novel applications. Examples of these strange behaviors include the increase in strength and conductivity, and the change in color and refractive index [1]. Nanotechnology requires the ability to see and control atoms or molecules in the scale of the nanometer. However, it is impossible for humans to see atoms with the naked eye, even with the help of an optical microscope. In order to observe the nano-world, several new-type microscopes were invented, such as the scanning tunneling microscope (STM) and the atomic force microscope (AFM). These microscopes make use of tiny, yet exact nanoscale movements to ensure a precise mechanical scanning of the surface of a specimen, such that scientists can probe and observe the nano-substances [1]. The earliest example for nanotechnology dates back to 1989 when a group of scientists from IBM spelled the company name in atoms using STM the team was able to literally position Xenon atoms on a background of copper substrate. This breakthrough demonstrated the possibility of manipulating matter with a precision up to the nanoscale. After more than 20 years of nanoscience research and development, applications of nanotechnology have promisingly improved different sectors of technology and benefitted society in areas including medicine, food safety and the information industry. With the help of nanotechnology, people can now effectively manipulate various traits of different materials [1]. There are many commercial products on the market that depend on nanotechnology. One example is the photochromic eyeglasses, in which its color varies with the background UV intensity. The secret behind the UV sensitivity of the photochromic eyeglasses is the clear nanofilm on the lens. Not only does it provide UV resistance, but it also makes the glasses water-repellent, scratchresistant, self-cleaning and offers an antifogging property. It is hard to imagine that a film with only a few nanometers thick can be so multifunctional. But nanotechnology makes it possible [1]. Besides nanofilm, carbon nanotube sheets are also a typical application of nanotechnology in daily life. A carbon nanotube is strong and stiff, yet lightweight,

21 durable and resilient, which makes it an ideal material for many items, such as sports equipment, safety wears, vehicles and even for building and construction. Other products of nanotechnology include automotive catalytic converter, household stain removers, high-power rechargeable battery and high- performance sunscreen [2]. On top of commercial products, nanotechnology has improved our society in different ways. In electronics and the IT section, nanotechnology is applied to diminish the size of transistors and boost their performance. Smaller and faster transistors greatly improve the portability and memory storage of electronic devices. Nanotechnology is also crucial in refining traditional energy sources and enhancing alternative energy. By improving the combustion efficiency and catalytic removal of pollutants of fossil fuels, nanotechnology reduces the burden of fossil fuel consumption to the environment. Moreover, nanoparticles and semiconductors play an indispensable role in the manufacture of solar cells, which advances the renewable energy industry [1]. Nanotechnology has made use of the special properties of nanoscale materials to achieve novel applications in the past years. Furthermore, there are many studies about applying nanotechnology in handling energy crisis, pollution reduction, cancer treatment, and creating superconductors. As a new research field, nanotechnology still has a huge potential to develop and is expected to bring impact to the world. References [1] Nanotechnology 101. National Nanotechnology Initiative. Retrieved from [2] Pacheco-Torgal, F., Jalali S. Nanotechnology: Advantages and drawbacks in the field of construction and building materials. Construction and Building Materials (2011). Vol. 25. Issue 2. Retrieved from pii/s

22 Just off the coast of Indonesia, the relatively unknown island Krakatoa had been a place of tranquility until a violent volcanic eruption threw its ecosystem out of balance in Undoubtedly, reading about volcanic eruptions conjures horrific images of fiery infernos. At first glance, it seemed that nothing was fated to live there again. However, the area was teeming with life in just a few years after the eruption. It even rejuvenated itself as a tropical jungle just 20 years later. Life finds a way, as always. This is usually brought about by ecological succession, which allows new communities to emerge. There are several possible scenarios. If it is an underwater eruption, the magma that has spewed out will cool and harden once it comes into contact with water, forming new land. Alternatively, if an eruption occurs inland, be it on the mainland or an island, almost all life on the surface surrounding the eruption zone will be wiped out, the coverage of which varies each time, and volcanic ashes will coat its surface. In both cases, succession of life may occur, but through drastically different means. In the first scenario where the eruption happens underwater, primary succession occurs subsequently. Primary succession is the process of the emergence of life from barren land over a long period of time. At the initial stage of the process, pioneer species such as lichens first grow on the barren land. When they die and decompose, they form soil, enabling the colonization of other plants. This process usually takes a long time. Eventually, seeds carried by ocean currents and in bird droppings lead to the emergence of new plants. The soil also thickens enough to allow a dominant type of vegetation to grow. As for the second scenario, which involves inland or island eruptions, secondary succession occurs. Secondary succession refers to the repopulation of an area after a cataclysmic disturbance. It is similar to primary succession, except that it already has soil. Therefore, it does not require pioneer species to form the initial layer of soil. Similarly, new plants are able to populate the area until a dominant type of vegetation emerges. As such, disaster-struck areas once again find ways to live. While volcanic eruptions seem to be a set-back for life due to the long time it takes for ecological succession to occur, studies have actually shown that regions affected by volcanic eruptions have higher biodiversity. It is because the eruption brings forth magma and volcanic minerals to the surface, which contain nutrients for all types of plants. Hence, the soil serves as fertile breeding ground. (Fun fact: The River Nile in Ancient Egypt brought alluvial soil to its banks similarly because of past volcanic eruptions in the mountains upstream.) Furthermore, due to the tectonic shift that accompanies the eruption, the altitude of the surrounding landscape is changed. This change causes a huge shift in climatic conditions, which makes it feasible for a more Rising from the Ashes: Ecological Succession after Volcanic Eruption By Henry Lau

23 diverse range of plants to grow. Plants with different climatic preferences, which were unable to grow previously, can happily thrive there post-eruption. How then, do volcanic eruptions affect the fauna of the area? Animals on land usually flee from the eruption for survival. New species of animals could be attracted to the post-eruption areas due to the emergence of new plants. However, most animals on islands are not so fortunate. Most of them die since there is nowhere to escape to, unless they are protected by some natural shelter. In a majority of cases, only new species of birds emerge after island or underwater eruptions. A notable example is the eruption on Surtsey Island in 1963, where new species of birds appeared after the eruption. Marine life also benefits from island or underwater eruptions. Nutrients from the magma can flow into the surrounding ocean bed which can give rise to more aquatic flora, thus attracting more marine animals to the area. Volcanic eruptions are not just stories of destruction. The cycle of life continues, and in greater abundance and diversity for plants and animals alike. References [1] Bressan, D. Rising From the Ashes - The Colonization Of A Volcano s Ground By Plants. Forbes (2016). Retrieved from [2] Bagla, P. Earthquakes, Volcanoes May Be Tied to Species Diversity. National Geographic News (2002). Retrieved from nationalgeographic.com/news/2002/03/0327_0327_cataclysmic.html 21

24 Have you ever heard of time reversal? The term may spark your imagination of fascinating time-traveling adventures like what you can see in films. While that is impossible in reality (yet), the concept of time reversal has indeed been around for many years. It has led to various helpful applications in fields including medical imaging, telecommunications and tactile objects. Prof. Mathias Fink has spent nearly 25 years study i ng the ti me reve r sa l tech n i que and i s one of the leading scientists in the field. He has pioneered the development of time - reversal mirrors and time reversal signal processing. What s more, he has turned many of these concepts into useful applications. He has more than 60 patents, and launched four companies with nearly 270 employees. We talked with Prof. Fink to learn more about his marvelous work after he gave a lecture at HKUST. Medical imaging, telecommunications, tactile objects All these applications of time reversal concepts share one thing in common: they are about waves. The time reversal technique can be used to control waves. It s a kind of time machine, but it s a time machine for waves, Prof. Fink said. Indeed, there are many forms of waves and they play an indispensable part in various aspects of our lives. Prof. Fink said, Waves are everywhere. When I speak to you, I send acoustic waves. When I use my telephone, I send electromagnetic waves. When I send ultrasound to the body to make an image, it travels as waves. If you use the time reversal technique, you can get better images, and you can do better communication. This is an interesting concept. It is about how we can better control waves. Many of you may think that waves go only in one direction. So how does time reversal work on waves? Let s imagine that a source is sending signals to a target. The signals may be scattered in the room. Simply put, when time reversal is applied, the signals received by the target are reversed and then sent out. The first signal received will be sent last; the last signal received will be sent first. When the process is repeated, the waves emitted will eventually focus on the source. The signals will no longer be scattered. In other words, no signals may be picked up anywhere else in the room. When applied to telecommunications, time reversal can make signal transmission more secure, ensuring that only the destined receiver can get the transmitted message. The technique has m i T f o Applications 㛰㱹㛰偤怵㘩敺 㻻Ƣ怀婅 ㇽ孺 偖ペ 䦸 曢 Ḕ䙫㘩敺㖬堳ガ䮧Ə暽䄝㘩敺㖬堳Ƌ㚒㘩ƌḍ 堳ƏἭ 㘩敺 㻻䙫㥩 㗐ⷙ 怀㥩 僤 䔏䙫 ㆰ䔏Ə䮫䕮 憒 ㇷ 曢 态姱⑳姟妡ㆰ䔏 s r e v e R e l a 憒 ㇷ 曢 态姱⑳姟妡ㆰ䔏üü怀Ẃㆰ䔏 堺惤㛰 ῲ⅘态滅Ɲ Ὸ惤⑳㳉㛰旃 㘩敺 㻻 堺 Ọ 㳉 㕀 媑Ɲ 怀㘖 䨕㘩敺㩆 Ə㳉䙫㘩敺㩆 ⅝ 㳉䙫䨕桅 Ə俳 ⑳ㇸῸ䙫䔆㴢 0DWKLDV )LQN㕀 䟻䩝㘩敺 㻻 堺ⷙ 徸 Ə㘖 ざざ䛟旃Ə㕀 姊憲媑Ɲ 㳉䄈嘼 䕝ㇸ媑婘㘩Əㇸ䙣 怀㖠杉䙫 Ə 柿ṭ㘩敺 㻻揈⑳㘩敺 㻻姱噆嘼䏭䙫䙣 偙㳉 䕝ㇸὦ䔏曢婘㘩Ə㛪䙣 曢䢨㳉 䕝ㇸ 䔏嵬偙㳉怙 ⰼ 㭋 Əẽㇷ 㘩敺 㻻䙫㥩 弰 ㇷ㗌 ㆰ䔏 ẽ㒨 堳憒 ㇷ Ə 㛪Ọ㳉ₚ忨 䕝 怲䔏㘩敺 㻻 堺Ə Ọ 㛰 柬 敺㒨㛰 徸 ⷌ䙫⅓ 0DWKLDV 㛛 䙫ㇷ 㛛 䙫态姱 怀㘖 ῲ㛰旃ㇸῸ Ἴ Ọ )LQN㕀 㗐 榀㸖䦸 㻻嬂ƏㇸῸ⑳ẽ怙堳 娑Ə䴗 㛛 㳉䙫㛰嶊㥩 偤ẽ䙫 Ẓ

25 b e e n a p p l i e d to c o m m u n i ca t i o n b et w e e n submarines. In the future, it might even be applied in 5G communications. Prof. Fink has also developed useful medical applications of time reversal. For example, he has built an apparatus to locate a kidney stone in a human body, so that it can be destroyed accurately. Another apparatus he developed can provide ultrafast imaging (10,000 frames per second). It can measure the stiffness of tissues and thus detect tumors. Better diagnosis can be conducted. The appa ratus has been sold and used in medical institutions al l over the world. w e i v r e t In h t i w Prof. Fink believes that collaboration between different disciplines can boost innovation. For example, closer collaboration bet ween pure s c i e n ce a n d e n g i n e e r i n g m a y b r i n g m o re oppo r tunities to push new ideas and create new things. As time goes on, there will be more research on time reversal and more applications developed. A new era of technology may be coming. s a i F h i nk t a M. f P ro By Teresa Fan 㣈慖 ਢ Іᅋ ޟ ᔖҢ!ȹ!ட Mathias Fink ௲ ạ婴䂡㳉 僤㜄 ῲ㖠 怙Ə㘩敺 㻻 㘖ầ 晋ṭ曢姱㖠杉䙫怙㭌Ə0DWKLDV )LQN㕀 ẍ怲䔏㘩敺 溣 Ƣ婍ペ 㛰 ῲ㹷栔㭊 䙣 姱噆Ə怀Ẃ姱噆ㇽ㛪㕊 㻻 堺Ə䟻䙣ṭ Ẃ憒 娔₀ ⅝Ḕ 㬥娔₀僤 ạ檻 ㈦敺 䰈 Ὥ媑Ə䕝 怲䔏㘩敺 㻻Ə䙣 䛕㨀㔝 䙫姱 ⅎ䙫儵䟚ə㛰 㹽䢡 晋儵䟚 㬥娔₀ Ọ 檿 噆㛪墒 弰Əⅴₚ忨 䬓 ῲ㔝 䙫姱噆㛪孱ㇷ㛧 怆ㇷ Ƌ㮶䦹 ƌə Ọ憶 䴫主䙫 䧲 Ə 俳 ῲ䙣 䙫姱噆Ə㛧 㔝 䙫姱噆㛪楽ℯ墒ₚ忨 憴壮㭌橆Ə 㸓兒䘋Ə Ὥ㛛㹽䢡䙫娡㖞 怀㬥娔₀ⷙ墒 䔳 䙫憒 䙣 䙫㳉㛪㼟㼟暭Ḕ㖣㹷栔Ə 㛪 䏥㕊 䙫ガ㲨Ə㈦敺䙫 䘩㩆㦲 䔏 ⅝ẽ 㖠惤 㛪 㔝 姱噆 0DWKLDV )LQN㕀 䛟ῈƏ巏䔳 䙫 ὃ 㖗ƏỌ 㞃ㆰ䔏怀 堺 曢 态姱Ə姱噆ₚ忨 孱 㛛 Ə 䦸 䔳⑳ⷌ䧲䔳䂡ὲƏ⅐㖠㛛䶱 䙫 ὃ Ὥ 㛛 怇 䢡ῄ 㛰 䙫 㔝俬僤 㔝 姱ざ 怀 堺ⷙ䵺墒ㆰ䔏 㖗ヶ ⑳㖗Ṳ䉐䙫㩆㛪 暏吾㘩敺㴨怄Ə 㛪㛰㛛 㘩敺 㽂刮态姱Ə Ὥ䔁凚㛰㩆㛪ㆰ䔏㖣 *态姱 㻻䙫䟻䩝⑳ㆰ䔏䙣ⰼƏ ῲ㖗 堺㘩Ịㇽ Ὥ 23

26 Prof. Ho Yi Mak (Associate Professor, Division of Life Science) ഫ㧟 ௲薥䚚 䭌ⳳ乶 㛔㔃薦 Prof. Yang Wang Wang (Dean of Science; Chair Professor, Department of Mathematics) ප ௲ 薥䖁ⳳ柝柝曲薸㛳ⳳ乶岖〢㛔㔃薦 with HKUST Scientists ऋσऋᏰড় ޟ ᇄ Dr. Jason Chan (Lecturer, Department of Chemistry) ങ໙റ ρ薥⒑ⳳ乶岖 薦 Whose thesis/scientific work would you like to read about? Could you please tell us more about the scientist and his/her work? Dr. Jason Chan: It is difficult for me to single out a scientist by name. I think that most PhD theses contain an interesting story and the most exciting ones are those that are currently being written since they represent our latest advances in science. I am more curious to read some historical works written by alchemists and early-day chemists (ca ). At that time, chemistry or alchemy was pretty much a mythical subject. Chemicals and elements were given elegant names, e.g. vitriolated tartar (potassium sulfate) and butter of arsenic (arsenic trichloride), and strange, cryptic symbols. Chemical reactions have been postulated to be a result of the transfer of phlogiston a fire-like element that was supposed to give a substance flammability. I find it fascinating to learn about those totally different schools of thinking on chemical reactions before the atomic theory arrived. It also shows me that the later alchemists and modern-day chemists have something in common. They have always been philosophers who carefully observed experiments and summarized their data to arrive at their best logical interpretation of chemical phenomena. And sometimes, it is just cool to read some old style English, laden with fancy and obscure alchemical terms and drawings. わ 㜂斘孧 ἴ䦸 䙫媽㕮ㇽ吾ὃƢ僤 Ẳ䴠 怀ἴ䦸 ⅝䟻䩝Ƣ 攱惜 濣 僤 凰 ἴ䦸 䙫婘 曊 ㇸ婴䂡 㕟 媽㕮惤 ῲ㛰嶊䙫㔬ṲƏ俳悊Ẃ㭊 㒗 晵㮜䙫媽㕮 㛧ịạ凯 Ə 䂡怀Ẃ媽㕮㭊㭊Ị塏吾㛧㖗䙫䦸 怙䧲 ㇸ Ẃ䔘䄰憸堺 ⑳㗐㜆 㒗 䙫㭞 吾ὃƋ䳫 ƌ㛛ㄆ凯嶊 䕝㘩 ㇽ 䄰憸堺 䭾㘖 ῲ䥅婘刓䙫栳 䛕Ə ⑳K䴇墒峍ṯṭℑ暬䙫 䨘⑳ 䙫䥅䦿䬍噆Əὲ 䡒 慟 䙫愹䟚Ƌ䡒慟戧ƌ 䠞䙫䉂㲠Ƌ 㰖 䠞ƌ ㆰ墒婴䂡 㘖䆪䴇弰䧢䙫䴷㞃 ă 䨕桅ἣ䁒䙫K䴇Ə僤峍ṯ䉐峑 䆪 䏭媽 䏥 Ə㛰 䄝 䙫 ㆰ ペ 媑Ə怀Ẃ 媑 ạ Əẍ桖䤡 㜆䙫䄰憸堺 ⑳䏥Ị 㛰 Ẃ⅘ 滅 ẽὸ 䛛Ⱈ 㨊Əẻ䴗妧 樾ḍ两䴷㕟㓁ƏỌ 䏥屈䙫㛧 恶弖㻻习 㛰㘩 斘孧 Ẃ 㛰取湾俳壮曃䙫䄰憸堺媅⑳ 䕒䙫 勘 媅㘖 㛰嶊䙫 A Choice Collection of Rare Secrets (1682)

27 Last October, Stephen Hawking allowed his PhD thesis Properties of Expanding Universes to be available online to the public, hoping to inspire others to think, learn and look up at the stars and not down on their feet. It was accessed more than 2 million times within just a few days. We chatted with three scientists from different fields of science at HKUST to learn more about their favourite scientific work, inspiration and advice for students. Havee you been inspired d or intrigued by any particular science during scien nce discoveries dur ring your journey of science educa ation/research? education/research? Prof. Ho Yi Mak: Mak: I have alw ways had a keen intere est in the discovery of prealways interest humaan fossils. The evolutio on of modern humans is a historic human evolution fascinating to opic. With the advent off highly sensitive methods topic. to sequence ancient a DNA samples, wee now have a much better understandin g of our own ancestors and a extinct cousins. cousins cousins. It is understanding gratifying to incorporate a childhood interest into my classroom teaching of human genetics. Prof. Yang Wang: I am a science buff, so I have been inspired and intrigued by many scientific discoveries. I can honestly say that you are not going to find anyone who likes science NOT to be inspired by the discovery of DNA and its broad ramifications. People like Hawkins have inspired millions of people to study science. But as a mathematician, if I have to pick one thing, I would go with something much closer to my heart - the rise of machine learning and AI. In my view, machine learning and AI have dramatically changed how we understand things, which will yield more insight in our pursuit for scientific discoveries. In fact, machine learning and AI have already helped us make groundbreaking new discoveries in medicine, biology, astrophysics and other areas of science and engineering. Could you offer some advice to secondary school students who are interested in pursuing education in science? Prof. Ho Yi Mak: Stay curious and be open to topics that fall outside the syllabus. Prof. Yang Wang: One of the biggest concerns of mine is that secondary students are taking less and less mathematics, at a time when mathematics plays an increasingly important role in all aspects of the economy and society. Once entering HKUST, many of our students are poorly prepared mathematically to move on to study science and engineering. So if I have to give one advice to secondary school students, I would ask them to go beyond just the mandatory part of the mathematics curriculum. It will be the best investment they can make for their careers. ўԑϊтȃ အ߇ᓓߜӵᆩΰϴ Οт ޟ ρ Мġ ș ġ ԇ ᑷ ޟ ܒ Ȃ ה ఖ ஊ т Ρ Ճ ڷ ᏰಬȄӵ ЈϞϱȂ Мϐ 摰 ijı ı ԩȄ ר ঈ ᇄ ऋσ έӫ پ ՌϚ ӣ ऋ Ᏸ ሴ ޟ ऋ Ᏸ ড়ġ հட ȂΟ тঈശ དྷ ޟ ऋᏰ ـ ȃᕕ ޟ ġ ЅϠᏰҡ ޟ ដȄ 䢏 㐗佰 䛒䤴䕂弌䣉ᳫ濕 㖼 ᶹḓ䢏 䔺䊼ヾ ⷓ ピ 䔺濨 浣㔥 㐗 濣 ㇸ 䛛 ạ桅 䟚䙫䙣䏥㛰吾㾪 凯嶊 䏥Ịạ桅䙫怙 㘖 ῲ ạ 䙫婘栳 Ị'1$㨊㜓Ọ檿㔶ㄆ 㖠㲼 Ọ ƏㇸῸ䏥 凑ⷘ䙫䤽ℯ⑳ⷙ䴼䨕䙫 塏Å 㛰ṭ㛛㷘 䙫 ṭ姊 僤 䫌 䙫凯嶊坴 ㇸ䙫ạ桅恡ₚ 㕀 ḔƏㇸ 㭋ㄆ 檿凯 㬨 㐗 濣 ㇸ㘖 䦸 俬Ə 㭋 娘 䦸 䙣䏥㈧ 䍙 䙣 ㇸ Ọ傖 媑Ə 㛪 ῲ㱹㛰 '1$ ⅝ 㳂 柦 䙫䙣䏥Ḕ䍙 䙣䙫䦸 俬 更憸Ḳ桅䙫䦸 滺 ṭ㕟 Ọ䙥吓姯䙫ạ摤䟻䦸 䄝俳ὃ䂡 㕟 Ə 㞃ㇸ 柯恟㒮Ə ㇸ㛪恟㒮 㨊ㇸ㛛ㄆ凯嶊䙫㝘奦Ɲ㩆 侹⑳ạⷌ㙡僤䙫凯嵞 ㇸ 婴䂡㩆 侹⑳ạⷌ㙡僤 㔠孱ṭㇸῸ Ṳ䉐䙫䏭姊Ə㛰 ㇸ Ὸ 忤㰩䦸 䙣䏥䙫怵䧲Ḕ 㛛 㷘 奲姊 Ṳ Ə㩆 侹 ⑳ạⷌ㙡僤ⷙ ㇸῸ 憒 䔆䉐 檻䉐䏭 ⅝ẽ䦸 ⑳ⷌ 䧲柿 䩨䠛 䙫䙣䏥 Ḟ侻 㽸㗇 䛒娾䢏 䕂ᳫ 䏝 ṙ ᵙⶸ娮濨 浣㔥 㐗 濣 Ṳ䉐ῄ Əḍ 媙䧲Ḳ 䙫栳䛕 敲㔥ㄲ 㬨 㐗 濣 ㇸ㛧䂡㒻 䙫 栳Ḳ 㘖䏥 㭊 㕟 䵺㿆⑳䤥㛪 㖠杉 ㉕㻻吾嵱䙣憴奨妹剙䙫㘩 Ə 侹㕟 䙫Ḕ 䔆 俳嵱Ὥ嵱 䦸 䙫娘 䔆惤㜑㛰恐䕝䧲 䙫㕟 䟌嬿Ə䂡 侹䦸 ⑳ⷌ䧲 㹽₀ 㭋 㞃奨ㇸ䂡Ḕ 䔆 ᾂ 柬 字Əㇸ㛪 字ẽῸ 孧 㕟 媙䧲Ọ 䙫惏 Ə怀 㘖ẽῸ䂡凑ⷘ偞㥔䔆㶖ὃ 䙫 㛧 岮 Visit our website at sciencefocus.ust.hk to read the complete interview with the three scientists! 妉㻍塻Ƽ䢏墾ƽ䱰䦗VFLHQFHIRFXV XVW KN濕摯娾 ḋ䢏 䕂 㐲㉟壨濊 25

28 Last Male Northern White Rhino Dies On 19 March 2018, the world s last male northern white rhino, Sudan, died at the age of 45. With the loss of Sudan, his daughter and granddaughter become the only two female northern white rhinos left in this world, making the subspecies on the verge of extinction. Rhinos have been targeted for their horns due to the alleged medicinal value. Scientists are now exploring ways to save the subspecies by artificial insemination using Sudan s genetic mater ials or cross-breeding bet ween northern white rhinos and southern white rhinos. Science News ऋᏰ ᆸ 㻓傦䰓䣬䕂 㑷䔻䄾䄙 䔳 㛧 栔暫 㖠䙤䉧䉂嗮Ḡ㖣 㛯 㗌Ọ ṻ㭙ḳ潈怄 暏吾嗮Ḡ䙫曉 Ə䉇䙫 ℹ⑳ ℹᾦㇷ䂡ṭ 䔳 棿䙫⅐栔暳 㖠䙤䉧䉂Əị㭋ẅ 䨕㿼减䴼䨕恱 䉧䉂妹墒好䂡㛰嗌䔏 Əị䉧䉂ㇷ䂡 䍜㮡䛕㨀 䦸 䏥㭊娔㲼 㔸怀ẅ䨕Ə Ọ嗮Ḡ䙫恡 ₚ䉐峑怙堳ạⷌ ㇽ 㖠䙤䉧䉂 㖠䙤䉧䉂Ḳ敺怙 堳愴䨕 Interested in science and writing? ᄇऋᏰ ڷ ቸհԤᑹ፸ȉ Submit a science article for a chance to win an Apple ipad AND have it published in future issues of Science Focus! For more competition details, please visit: ඪҺоऋᏰ ᚠ ޟ МണȂձ Ԥᐠ ថ គ ݎ ipadκഋȋ ዩհ ӵґ پ Ȯऋ ȯϛ юȅषདο ġ ӻшᗉ Ȃ ᘲ Ȯऋ ȯ ޟ ᆩમȄ Acknowledgements 䄷 傲姛 Print Advising 妬夠 HKUST Publishing Technology Centre 榀㸖䦸 䈯 堺Ḕ 2018 Published by School of Science, HKUST 榀㸖䦸 䏭 晉 䈯 G18 G Not for Sale (杅峊 )