You may have missed… cranberries prevent UTIs in women; whale body scrubs; ultrasonic drug delivery; and a hydrogel that absorbs more water the hotter it is

Your hit of the best of last week’s science.

Cranberry products can prevent urinary tract infections for women

The decades old myth that drinking cranberry juice prevents women from developing UTIs finally has medical evidence to back it up.

Australian researchers completed an updated review of the scientific research on the benefits of cranberry products, determining that the juice and its supplements reduce the risk of repeat symptomatic UTIs in women by about 26%, in children by about 54%, and in people susceptible to UTI following medical interventions by about 53%.

The review included data from 50 studies, included more than 8,800 participants, and has been published in the journal Cochrane Reviews.

“The studies we looked at included a range of methods to determine the benefits of cranberry products. The vast majority compared cranberry products with a placebo or no treatment for UTI and determined drinking cranberries as a juice, or taking capsules, reduced the number of UTIs in women with recurrent cases, in children and in people susceptible to UTI’s following medical interventions such as bladder radiotherapy,” explains Dr Jacqueline Stephens, Flinders University epidemiologist and a co-author of the study.

“It’s also important to consider that few people reported any side effects with the most common being tummy pain based on the results. We did not find enough information to determine if cranberry products are more or less effective compared with antibiotics or probiotics in preventing further UTIs.”

The data did not show any benefit for elderly people, pregnant women or in people with bladder emptying problems. The researchers conclude that further studies are needed to clarify which patients with UTI would benefit most from cranberry products.

This hydrogel keeps absorbing moisture even as it gets hotter

The majority of absorbent materials lose their ability to retain water as you turn up the heat. But now researchers have found that that polyethylene glycol (PEG) – a hydrogel commonly used in cosmetic creams, industrial coatings, and pharmaceutical capsules — can absorb moisture from the atmosphere even as temperatures climb. 

“At first, we thought we had measured some errors, and thought this could not be possible,” says co-author Dr Xinyue Liu, from the Department of Mechanical Engineering at Massachusetts Institute of Technology (MIT) in the US.

“After we double-checked everything was correct in the experiment, we realised this was really happening, and this is the only known material that shows increasing water absorbing ability with higher temperature.”

The material is able to double its water absorption from 25°C to 50°C because its microstructure morphs from a crystal to a less organised “amorphous” phase, which enhances the material’s ability to capture water. 

Based on PEG’s unique properties, the team developed a model that can be used to engineer other heat-resistant, water-absorbing materials. They envision that these materials could one day be made into devices that harvest moisture from the air for drinking water, particularly in arid desert regions.

The research is in Advanced Materials.

Humpback whales exfoliate too

Humpback whales stop by the Gold Coast in Australia for a bit of pampering, according to a new study in the Journal of Marine Science and Engineering. Apparently, on their return journeys south to cooler waters, they use sandy, shallow bay areas to ‘roll’ around to remove dead skin cells. 

Marine ecologists used suction cups to attach tracking tags to the whales and observed them performing the full and side rolls on fine sand or rubble along the sea floor at depths of up to 49 metres.

“On all occasions of sand rolling, the whales were observed on video to be slowly moving forward with their head-first into the sand followed by rolling to one side or a full roll,” says Dr Olaf Meynecke, from the Coastal and Marine Research Centre at Griffith University.

“During the different deployments, the sand rolling was observed in the context of socialising. The behaviour was either following courtship, competition, or other forms of socialising.  

“So, we believe that the whales exfoliate using the sand to assist with moulting and removal of ectoparasites such as barnacles, and specifically select areas suitable for this behaviour.

“Humpback whales host diverse communities of skin bacteria that can pose a threat for open wounds if bacteria grow in large numbers.

“Removing excess skin is likely a necessity to maintain a healthy bacterial skin community,” he concludes.

A wearable patch that painlessly delivers drugs through the skin

Researchers have developed a wearable patch that applies painless ultrasonic waves to the skin, creating tiny channels that drugs can pass through to deliver much more targeted transdermal drug delivery.

“The main benefit with skin is that you bypass the whole gastrointestinal tract,” says Aastha Shah, a research assistant at MIT, and co-lead author of a new paper describing the patch in Advanced Materials.

“With oral delivery, you have to deliver a much larger dose in order to account for the loss that you would have in the gastric system.”

The lightweight, wearable patch is made of PDMS – a silicone-based polymer that can adhere to the skin without tape. Several disc-shaped piezoelectric transducers, which can convert electric currents into movement, are embedded in cavities containing drug molecules dissolved in a liquid solution.

When an electric current is applied to the piezoelectric elements, they generate pressure waves in the fluid, creating bubbles that burst against the skin. These bursting bubbles produce microjets of fluid that can penetrate through the skin’s tough outer layer, the stratum corneum.

The current version of the device is capable of delivering drugs a few millimetres into pig skin. which could be used to deliver treatments for skin conditions. But the researchers say the approach could be adapted to increase the penetration depth for drugs that need to reach the bloodstream.