| RESEARCH HIGHLIGHTS |


of communications, from video playback application to network transmission, we could enhance the QoE through more efficient allocation of network resources.” The researchers developed an efficient


method to derive an ‘importance index’ for each video packet based on the video bit rate, which varies packet-to-packet depending on how much new information needs to be displayed — for example, slow scenes


with little movement require lower bit rates, while fast action scenes require very high bit rates. By prioritizing video packets — each


a fraction of an individual frame of video — based on bit rate and other network parameters, then inserting this priority in the QoS scheme in real time, the team was able to significantly enhance the perceived quality of streaming video among multiple users in a


laboratory environment with limited wireless bandwidth. “For the end user, video quality will be


improved with less distortion, while service providers can accommodate more users with the same network resources,” says Tan.


1. Li, M., Tan, P. H., Sun, S. & Chew, Y. H. QoE-aware scheduling for video streaming in 802.11n/ ac-based high user density networks. IEEE Vehicular Technology Conference (VTC Spring), 15–18 May 2016.


Antibiotics


OVERCOMING DRUG-RESISTANT LUNG INFECTIONS


Inhibition of RNA transcription (rifampicin) DNA Ribosomes


Inhibition of protein synthesis (tigecycline)


Inhibition of membrane synthesis (meropenem)


Disruption of cell membrane (colistin)


Triple-pronged attacks on microbes that cause life-threatening lung infections are much more effective than individual antibiotics, A*STAR researchers have found1. Using cocktails of antibiotics is promising for addressing the rising menace of multidrug-resistant microbes. Multidrug-resistant bacteria are the plague of the twenty-first century and are predicted


46 A*STAR RESEARCH


Using colistin in combination with other antibiotics (rifam- picin, tigecycline and meropenem) proved more effective in treating multidrug-resistant bacteria than applying the antibiotics individually. That is because the four antibiotics used had different killing mechanisms against microbes.


to become the leading cause of death by 2050, surpassing even cancer and diabetes, says Desmond Heng Wen Chien of the A*STAR Institute of Chemical and Engineering Sciences. “It is imperative that we act now to stem the rise of antimicrobial resistance and to mitigate its impact with more robust, but safer therapies,” he urges.


TAILORED COMBINATIONS OF ANTIBIOTICS THAT KILL MICROBES IN DIFFERENT WAYS ARE A POWERFUL WEAPON AGAINST DRUG RESISTANCE


In particular, superbugs that cause respiratory


lung infections are posing an increasingly omi- nous threat. They have dire clinical outcomes, with mortality rates reaching as high as 80 per cent for some infections. Furthermore, they have begun to spread from hospitals to the commu- nity at large. The last line of defense against such superbugs is the highly toxic antibiotic known as colistin, but there are recent reports of infections that are resistant even to that. Now, Heng and his co-workers have shown


that using three tailored combinations of colistin with two other antibiotics can effec- tively combat lung infections caused by multi- drug-resistant superbugs. They found that all three formulations were highly effective against the multidrug-resistance pathogens in the laboratory. In concocting these combinations, the team drew on initial laboratory screening data and existing clinical data to obtain more effective and robust formulations. Since the four antibiotics used in these cock-


tails employ different mechanisms to kill bacteria (see image), their ternary combinations exhibit significant synergistic and additive effects. Their combined effectiveness is much greater than


ISSUE 6 | JANUARY – MARCH 2017


Reprinted from Ref 1. Copyright (2016), with permission from Elsevier.


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