In afternoon trade, the S&P/ASX 200 Index (ASX: XJO) is on course to end the week on a mildly positive note. The benchmark index is currently up 0.1% to 8,212.2 points.

Four ASX shares that are rising more than most today are listed below. Here's why they are pushing higher:

4DMedical Ltd (ASX: 4DX)

The 4DMedical share price is up 27% to 56.5 cents. This morning, this respiratory imaging technology announced that it has signed a distribution agreement that appoints global healthcare giant Philips (NYSE: PHG) as an authorised reseller across the United States. This follows the signing of a teaming agreement with Philips back in January which aimed to establish a strategic collaboration to advance solutions to evaluate Veterans with deployment-related respiratory disease and other respiratory conditions as part of a broader lung screening initiative.

A2 Milk Company Ltd (ASX: A2M)

The A2 Milk Company share price is up almost 9% to $6.24. This appears to have been driven by reports that China is planning further stimulus measures that will boost consumer spending. According to Reuters, sources claim that China is planning to issue special sovereign bonds worth about 2 trillion yuan (US$284.43 billion) this year as part of a fresh fiscal stimulus. It notes that the some of the "proceeds will also be used to provide a monthly allowance of about 800 yuan, or US$114, per child to all households with two or more children, excluding the first child." A2 Milk's shares have now been halted.

De Grey Mining Limited (ASX: DEG)

The De Grey Mining share price is up almost 4% to $1.39. This morning, this gold developer dismissed speculation that it was a takeover target. It notes that the media claims that De Grey Mining has received a buyout proposal from Agnico Eagle Mines (NYSE: AEM). However, the company responded very briefly and stated: "The suggestion in the article is incorrect and the Company notes it is pure speculation. The Company's policy is not to comment on rumours or media speculation."

Treasury Wine Estates Ltd (ASX: TWE)

The Treasury Wine share price is up almost 7% to $11.82. This also appears to have been driven by optimism that Chinese stimulus measures will boost consumer spending. This certainly comes at a good time for Treasury Wine given that the Chinese government recently removed tariffs from Australian wine. It is currently in the process of re-entering the lucrative market.