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How Green Fluorescent Proteins Bioluminesce: “
Berkeley researchers have identified the mechanism that makes green fluorescent protein (GFP) light up the way it does. They used femtosecond lasers to image the molecules as they undergo structural changes that cause them to fluoresce.
The transfer of a positively-charged hydrogen atom – a bare proton – along a reaction chain in GFP generates a green flash of light. The laser snapshots show that when the light absorber, or chromophore, nestled in the middle of the protein barrel absorbs an incoming photon of blue light, it starts vibrating, and the electrons start sloshing around the chromophore until it is aligned just right for the proton to hop via a water molecule to a nearby amino acid in the protein. From there, it continues down the reaction chain, creating a state with a negatively charged chromophore that emits green light.
Previous studies had shown that after the chromophore absorbs blue light, it undergoes proton transfer, and green light is emitted. In the current study, Mathies, Fang and their colleagues could actually resolve the early stage of this proton transfer reaction, taking snapshots of the vibrational wagging of the chromophore skeleton in sync with the electron cloud in the chromophore sloshing back and forth. However, the wagging oscillation might have stopped after a few picoseconds, when the chromophore and its vicinity are aligned just right for the proton to hop off down the reaction chain, and the whole protein shines bright green – which it does in its own good time, in about 3 nanoseconds.
Femtosecond stimulated Raman spectroscopy on GFP involves hitting the protein molecule with an approximately 80 femtosecond pulse of ultraviolet light, which excites many vibrational modes in the molecule, and then a one-two punch of picosecond red and femtosecond white light to stimulate Raman emission. The spectrum of emitted signals tells researchers the vibrational modes of various parts of the molecule. If the molecule is in the middle of a reaction, the emitted light at different time delays tells the researcher the various steps the molecule goes through during the reaction.
Berkeley Lab press release: Vibrations key to efficiency of green fluorescent protein …
Abstract in Nature: Mapping GFP structure evolution during proton transfer with femtosecond Raman spectroscopy
(Via Medgadget.)
2 Online Guides to Check Your Illness Symptoms Online: “
There are times when we want to check certain illness symptoms we or our loved ones are experiencing. We may not be sure if the symptoms warrant further investigation or we might just want to satisfy our curiosity about health and fitness in general.
In this article, let us look at two online guides to check your illness symptoms online, which are extremely easy to use and provide information about probable causes.
Before we proceed, it is necessary to stress that these guides should not be used as a substitute for professional medical advice. It is better that you use these tools as a supplementary resource to get more information, while you may be waiting for your doctor’s appointment, or to learn more about certain illnesses.
Check Symptoms Online With WebMD Symptom Checker
Web MD Symptom Checker is an easy to use interactive tool, where you select specific symptoms and it identifies possible causes.
You start by selecting your gender and age, after which you can specify the symptoms in three ways in the left panel:
- You can identify the symptom by zooming in on the affected body part in the interactive map of the human body on the left.
- You can select from a list of 76 possible symptoms organized in an alphabetical list and a common symptoms list.
- You can search for symptoms using the search box.
If applicable, you can select and add more symptoms. Once you identify the symptoms, the Symptom Checker shows you a list of possible conditions that may be the cause of them. You can check more about any possible condition right within the Symptom Checker.
For each condition, Symptom Checker provides you with an overview, a list of all symptoms associated with that condition, and related articles and videos on the WebMD website.
Mayo Clinic Symptom Checker
Use this guide to discover the most common causes of the most common symptoms. The Mayo Clinic Symptom Checker takes a different approach to isolating possible conditions than the WebMD version.
You first select between Adult and Child symptoms on the first page. For Adults, there are 28 common symptoms listed. After you choose one kind of symptom, the next page lets you select related factors depending upon the selected symptom:
- Details such as persistent/intermittent, started suddenly/gradually, etc.
- Whether it affects both pairs of hands/legs/etc.
- Details of the pain – duration, pattern, severity, location
- Trigger factors such as injury, repetitive use, stress, change in sleeping pattern, etc.
- Relieving factors such as medication, rest
- Accompanying symptoms associated with the selected symptom
Note that this page is specific and different for each of the 28 symptoms listed in the first page. The questions on this page are similar to what a doctor would ask you after you tell him about a symptom. So the process actually feels similar to an actual diagnosis!
After you make the appropriate selections on this page, the next one gives you possible causes of the symptoms. Here, you can see all associated factors or symptoms related to this condition.
Clicking on the condition takes you to the main page for it on the Mayo Clinic website. Here, you will find a wealth of information and resources such as description, causes, risk factors, tests and diagnosis, treatment and drugs, home and alternative remedies, prevention, etc.
For more health-related articles, check out our health category.
Did you find these tools useful? Any other online illness guide that you prefer? Tell us in the comments!
Did you like the post? Please do share your thoughts in the comments section!
New on MakeUseOf ? Get cheat sheets and cool PDF guides @ www.makeuseof.com/makeuseof-downloads/
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(Via MakeUseOf.com.)
Melody Transcatheter Cardiac Valve Replacement Shows Good Results in Children: “
Cardiologists from Miami Childrens Hospital, Morgan Stanley Childrens Hospital, New York, and Childrens Hospital Boston just published preliminary results from the study of Medtronics Melody® Transcatheter Pulmonary Valve in 34 children and young adults who were implanted with the device for dysfunctional right ventricular outflow tract conduits. The early results are promising and may help the Melody valve get approved in the US as the first transcatheter cardiac valve on the market.
All patients underwent cardiac catheterization with the intention of implanting the artificial valve, and 30 of the 34 underwent actual implantation attempts, of which 29 were successful. Three patients (9 percent) had complications during implantation, but all survived.
At follow-up six months later, no patient had more than mild pulmonary regurgitation. Of 24 patients who had Class II or III heart failure (mild to moderate limitation of physical activity) before the procedure, 19 had improved by at least one functional class at six months, and no patient’s function had declined.
Eight of the 29 devices developed partial fractures during follow-up, and 3 patients required a second Melody valve (inserted inside the first one) for recurrent blockage.
Children’s Hospital Boston press statement: Catheter-delivered Valve May Help People with Heart Defects Avoid Multiple Surgeries; Medtronic statement: Melody® Transcatheter Valve Demonstrates Encouraging Results in Study on Patients with Congenital Heart Disease…
Abstract in Journal of the American College of Cardiology: Implantation of the Melody Transcatheter Pulmonary Valve in Patients With a Dysfunctional Right Ventricular Outflow Tract Conduit …
Product page: Melody® Transcatheter Pulmonary Valve and Ensemble® Transcatheter Delivery System …
Flashbacks: Medtronic’s Melody Transcatheter Pulmonary Valve on Track for Approval ; Melody Transcatheter Pulmonary Valve Still Being Tested in the US …; The Melody Valve Approved in Canada; The Melody Transcatheter Pulmonary Valve
(Via Medgadget.)
Travel Secrets of Ulcer Causing Bacteria Revealed: “
A team from Boston University, MIT, and Harvard discovered how the H. pylori bacteria penetrate the stomach mucus to cause ulcers in the lining.
H. pylori secretes the enzyme urease, which interacts with urea in the stomach to produce ammonia–the ammonia is what neutralizes the acids in the immediate environment. The less-acidic environment de-gels the mucin, allowing the microbe to travel through it using standard, flagella-based locomotion, much like other swimming bacteria.
To confirm their findings, the researchers placed H. pylori into an acidic mucin gel in a laboratory setting. While its flagella moved, the organism could not. After the microbes secreted urease and acidity diminished, the microbes were able to forge through the gel.
Bansil and her colleagues next want to understand the progress of H. pylori-related diseases, particularly in the context of living hosts. The team is planning to work on new imaging techniques that may reveal even greater detail about the organisms and how they inflict damage on the human body.
H. pylori bacterium stuck in a mucin gel at pH4. The flagella rotate but the bacterium does not move freely. But it gains motility as it increases the pH level of the mucin:
This video clip shows H. pylori bacteria moving around in a mucin solution at pH 6. The higher pH level means the mucin is less solid and allows greater movement for the bacteria:
Abstract in PNAS: Helicobacter pylori moves through mucus by reducing mucin viscoelasticity …
Read on from the National Science Foundation: How Bacteria Get Past Our Defenses …
(Via Medgadget.)
In Depth: Everything you need to know about Android 2.0: “
Android 2.0 (formerly codenamed ‘Éclair’) is the latest evolution of the mobile OS developed by Google and the Open Handset Alliance.
This version is a chunky upgrade, superceding the current Android 1.6 software (dubbed ‘Donut’), which was actually considered ‘a minor platform release’.
The first phone to feature Android 2.0 will be Motorola’s comeback phone, the DROID (aka the dull-sounding Milestone in Europe).
It stands as an example of some the techno-goodness that inches Android 2.0 that little bit closer to bettering the Apple iPhone. For example, there’s…
Contacts 2.0 – MotoBLUR meets HTC’s Sense
The good news for future Android phones (but bad news for the Palm Pre) is that Android 2.0 significantly upgrades its contacts functionality. Multiple email accounts and contacts lists can all be cleverly mashed together, enabling you to sync your personal and work accounts into one easy-to-manage super-list.
A new API will also enable developers to develop widgets that can ‘provide synchronisation with additional data sources’. Think MotoBLUR-style Twitter and Facebook integration in the future.
A new ‘Quick Contact’ feature, meanwhile, seems to take its cues from HTC’s Sense UI. Quick Contact enables you to select a contact and view all the available ways that you can get in touch with them, i.e. by phone, SMS and email. This sort of integrated contacts feature already works impressively on the HTC Hero, which also extends the approach to Facebook status updates and Flickr photo albums.
MULTIPLE ACCOUNTS: The Android 2.0 OS not only supports multiple email accounts but it can merge them into one centralised inbox
QUICK CONTACT: Tap on a Contact and the new Quick Contact feature will show all the ways that you can contact them
You want Microsoft Exchange? You’ve got Microsoft Exchange
While earlier versions of the Android OS bolted Microsoft Exchange support on top of the core software stack, Android 2.0 now has this business-friendly functionality built-in.
That said, it’s not a mandatory Android feature – it’s up to the handset manufacturers to choose whether to include Exchange support in their mobile devices. But, with the VPN support that came courtesy of Android 1.6, Android 2.0 is in better shape for corporate use.
Multiplayer gaming via Bluetooth
The new Éclair update also brings Bluetooth 2.1 support to the Android platform with two new profiles – Object Push Profile (OPP) and Phone Book Access Profile (PBAP).
They might not sound like the sexiest of upgrades, but consider the possibilities here. OPP enables Android 2.0 handsets to send/receive files, paving the way for proximity-based multiplayer gaming, wireless contact/photo swapping and other P2P applications. While PBAP enables another device to access phone book information over a Bluetooth connection, enable in-car technology to display the contact name for an incoming call or let drivers dial their contacts direct from the dashboard.
Out with the old camera, in with the new
Android is far from a perfect operating system and some of its core apps are still a little rough around the edges. While version 1.6 improved both the functionality and the speed of the camera/camcorder application, Android 2.0 adds several extra features to boost performance, notably: built-in flash support, digital zoom, a scene mode, white balance, colour correction and macro focus options.
CAMERA MODES: The enhanced Camera application now supports additional photo features including digital zoom and colour correction
A virtual keyboard you won’t shout ‘gnnnghh!’ at
Android 2.0 also improves the virtual keyboard, which has always lagged behind the Apple iPhone’s QWERTY keypad in terms of usability. The Android keyboard has a narrower layout, with smaller virtual keys that are harder to hit accurately when typing at speed.
The iPhone combats this by invisibly enlarging the so-called ‘landing area’ of certain keys as you type. This is based on a probabilistic analysis of the word that you’re currently typing and by guessing the letters that you might be pressing next.
Android 2.0 now includes an improved keyboard layout that’s designed to make it easier to hit the right keys, while multi-touch support enables speedy, two-fingered key tapping. The new keyboard also boasts a smarter dictionary that learns from the words that you use most often (much like the iPhone).
Android 2.0 is ready for HTML 5 (even if you’re not)
The Android 2.0 OS features a revamped webkit browser with an actionable URL bar like Google’s Chrome. This enables you to bypass the Google homepage and use the URL bar as a search box. Android 2.0 also adds thumbnail images to bookmarks and double-tap zoom in/out functionality (but no Apple-esque ‘pinching’).
Android 2.0 also sneaks in HTML 5-friendliness, including tag support. In short: this will play HTML5 videos in full screen mode when you tap on them. And what about Flash 10? HTML 5 is designed to reduce the reliance on plug-in applications, but that will take some time to achieve. Support for Adobes format is on the way but doesnt make it into this Android update.
Get a FREE sat-nav with every Android 2.0 phone
Need another reason to love Android 2.0? How about FREE sat-nav software? Google recently announced Google Maps Navigation for Android 2.0. ‘This new feature comes with everything you’d expect to find in a GPS navigation system,’ wrote software engineer Keith Ito on the Official Google Blog, ‘like 3D views, turn-by-turn voice guidance and automatic re-routing. But unlike most navigation systems, Google Maps Navigation was built from the ground up to take advantage of your phone’s internet connection.’
Wait. There’s more…
Hands up who wants a better calendar? Android 2.0 delivers an enhanced agenda application that now has the ability to invite people to events and to show who’s attending (or not).
It also extends the search functionality to text messages and can be tasked to automatically erase old messages. Dig deeper and Android 2.0 also makes some other tweaks, including improved graphics performance through hardware acceleration and a new API for three-point multi-touch.
Will old Android phones be upgradeable to Android 2.0?
Yes. And no. Sony has already announced that the new Xperia X10 will be upgraded to 2.0 as soon as the software appears. The HTC Hero will also be ripe for an upgrade.
The company has recently admitted that: ‘Yes, we are working on an Éclair update for the HTC Hero’. But expect to wait for it. ‘Because Éclair is a significantly enhanced release, it will require some time to update Sense for this new version of the Android OS’, HTC added.
No word yet on whether the Motorola Dext (aka Cliq) can or will be upgraded to Android 2.0, ditto the Samsung Galaxy, the HTC Tattoo and HTC Magic. Contact your network provider for more information.
There’s a giant éclair on Google’s lawn…
The codenames for recent Android releases seem to be rolling out alphabetically and are being inspired by high-calorie patisserie items. Android 1.5 was designated ‘Cupcake’, while Android 1.6 was known as ‘Donut’. Android 2.0 continues the tradition with the codename ‘Éclair’.
Google erects oversize statues of each cake on its Mountain View campus to celebrate the release of each major Android version. What’s next? Fudge? Fritter? Our money is on ‘Flapjack’ for Android 2.1…
You can watch the Android 2.0 platform highlights video on the developer.android.com website.
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Hubble’s New Camera Delivers Another Stunner: “
The Hubble Space Telescope’s new camera is returning incredibly detailed, stunning images of space. This close-up view of an area near the core of the iconic Southern Pinwheel galaxy, or M83, shows very rapid star birth.
The image to the right of the entire galaxy, taken from the ground by the European Southern Observatory’s 2.2-meter telescope at La Silla, Chile, shows the location of the image above. Hubble’s detailed view reveals that the spiral arms of the galaxy, about 15 million light-years from Earth, are lousy with clusters of infant stars, only a few million years old. The clusters show up as red because of the hydrogen gas they emit, and they have blown holes in the brownish dust tracks of the arms.
The image also reveals around 60 supernova remnants, around five times more than had previously been seen. the different wavelengths of light captured by Hubble’s camera, from ultraviolet to near-infrared, gives scientists a look at stars in all stages of formation, which will help them understand the evolution of the Pinwheel galaxy, and give them insight into galaxy formation in general.
Images: 1) NASA, ESA, STScI/AURA. High-Def Version. 2) ESO.
Follow us on Twitter @betsymason and @wiredscience, and on Facebook.
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(Via Wired Science.)
How many people did the man-eating lions of Tsavo actually eat? [Not Exactly Rocket Science]: “
In 1898, railway workers in Tsavo, Kenya were terrorised by a pair of man-eating lions, who killed at least 28 people during a 10-month reign of terror. It ended in December when a British officer called Lt. Col. John H. Patterson killed both beasts. The man-eaters’ notorious exploits have been immortalised in no less than three Hollywood films, including most recently The Ghost and the Darkness. But despite their fame, no one is quite sure how many people they killed. The Ugandan Railway Company said 28; Patterson claimed it was 135.
Both parties had reasons to lie, either playing down or exaggerating the figures for the sake of reputation. But Justin Yeake from the University of California decided to find the truth by going straight to the source – the remains of the man-eaters, currently on display in Chicago’s Field Museum of Natural History. By studying the chemical composition of the lions’ hair and bones, Yeake estimated that they killed around 35 people, with a possible range of 4 to 72. Either way, Patterson’s claim was wildly exaggerated.
The Tsavo man-eaters at the Chicago Field Museum, taken by Jeffrey Jung
Yeake took samples of the lions’ bone collagen and hair keratin, and measured the ratio of carbon and nitrogen isotopes. Both can tell you about the items on a lion’s menu – bone collagen grows slowly and reflects the lion’s lifetime eating habits, while keratin from fast-growing hairs reveals the nature of its meals over the past three months.
Yeake compared these ratios to those of modern Tsavo lions, and matched them against those form various prey animals including giraffe, kudu, impala, zebra, buffalo and humans. The human samples came from remains collected by anthropologist Louis Leakey during his East African Archaeological Expedition of 1929.
The results showed that the diet of Tsavo’s modern lions consists almost entirely of grazing animals such as zebra, waterbuck and buffalo. The man-eaters were different. Yeake calculated that one of them probably ate around 11 people in its nine-month hunting spree, but focused mainly on expanding its tastes in herbivores.
His partner switched menus even more dramatically, moving to a diet of browsers (giraffe, kudu and the like) and humans. By winter, a third of his food came from freshly killed humans. This was the animal that caused the lion’s share of deaths among the railway workers, and Yeake estimates that he ate around 24, giving a total kill count of 35. Of course, these are only estimates, but there’s a 95% chance that the true figure falls within the range of 4-72.
These disparate diets make the cooperation between the two males even more astounding. Both specialised on different rare prey and, if anything, their tastes diverged even further from one another over time. And yet, they frequently exposed themselves to danger to kill animals that only one ate. That sort of behaviour had never been seen before or since. Perhaps by working together, they could scatter both humans and game, so that both could be fed? For the moment, we just don’t know.
Nor is it clear why the lions starting eating people in the first place, although Yeake has two theories. For a start, the lion that killed the most people had severe injuries, including diseases of the skull and teeth, skull evinced craniodental, poorly aligned jaws and a fractured tooth. It wasn’t exactly a king among beasts, and it supports the idea that big cats are more likely to prey on humans if they’re ill or impaired.
The Tsavo killings took place against a backdrop of intense environmental changes. Elephant populations had plummeted and as a result, woodlands were expanding and the savannah’s grazers were being driven away. The remaining herds were thinned by a 13-year drought and a pair of viral epidemics in 1889 and 1898. And just as these walking sirloins dwindled away and the lions started to hunger, a new type of prey arrived in the region – humans, charged with building the Uganda Railway. The rest is history.
The two lions, Lieutenant Patterson (in top-left) and a Taita ancestral shrine.
Reference: PNAS: doi:10.1073/pnas.0905309106
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