Mechanism of Suppressing ASR Using Ground Reactive Sandstone Powders instead of Cement

In order to understand the effect of powders ground from reactive sandstone replacing cement on reducing or suppressing alkali-silica reaction（ASR）, and to identify the mechanism of suppressing ASR by this powders, mortar and paste containing reactive sandstone powders of four replacement levels ranging from 10wt% to 40wt% and four specific surfaces areas ranging from 210 m^2/kg to 860 m^2/kg were studied. The experimental results showed that incorporation of 40wt% reactive sandstone powders could suppress ASR effectively except for mortar containing reactive sandstone powders with specific surface area of 610 m^2/kg, which disagreed with the most results reported that the higher reactive powder specific surface area, the smaller ASR expansion. By means of fl ame photometry, Fourier transform infrared spectroscopy（FT-IR） and thermo gravimetric analysis（TG）, the mechanism of reactive sandstone powders on reducing or suppressing ASR was soluble alkalis type of reactive sandstone powders and the competition of liberating and bonding alkali of cement paste containing reactive sandstone powders,when the ability of alkali bonding was greater than the ability of alkali liberation, ASR caused by reactive sandstone was supressed effectively.

Regulatory gaps in India’s medical device framework:The case of Johnson and Johnson’s faulty hip implants

The Johnson and Johnson faulty hip implant case represents one of the most significant crises in medical device history,impacting nearly 93000 patients worldwide.In response to alarming failure rates and a global recall in August 2010,countries such as Australia,the United States,and the United Kingdom quickly implemented revision surgeries and reimbursement programs to protect patient safety.In stark contrast,India's response was alarmingly delayed;defective implants continued to be sold even after the global recall.By the time the import license was revoked,and the Central Drugs Standard Control Organization issued a recall notice,these implants had already been involved in 4700 surgeries across India.This paper explores the systemic weaknesses in India’s medical device regulatory framework that contributed to this delayed action,resulting in many patients suffering from serious health complications.It highlights deficiencies in monitoring and reporting mechanisms,inadequate regulatory oversight,and insufficient approval processes.Furthermore,the inability to trace affected patients and provide necessary compensation underscores significant gaps in regulation.Although subsequent legislative reforms were introduced,this paper argues that substantial loopholes remain,posing risks for future incidents.Thus,urgent,comprehensive,and enforceable regulatory measures are needed to increase patient safety.