Concerns over Chinese economic slowdown weighed in worldwide stocks, with almost all major indexes closing in the red. In the US, the DJIA closed down at 16,001.89, having lost 312 points or 1.92%, the worst one-day decline in over a month. Commodities were under pressure amid news saying that Chinese industrial activity has fallen sharply in August, whilst the biotech sector also fell sharply, amid concerns that increasing political pressure will put an end to the latest drugs' price increases.…