Please answer this: Extract the answer to the question from the following context. Question: Why is PCR still unreliable? Context: Thus, the technological ability to detect any infectious agent rapidly and specifically are currently available. The only remaining blockades to the use of PCR as a standard tool of diagnosis are in its cost and application, neither of which is insurmountable. The diagnosis of a few diseases will not benefit from the development of PCR methods, such as some of the clostridial diseases (tetanus and botulism). These diseases are fundamentally biological poisonings by relatively small numbers of infectious bacteria that produce extremely potent neurotoxins. A significant proliferation of the infectious agent does not occur, this limits the ability of PCR to detect the presence of any bacteria.
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Answer: diagnosis of a few diseases will not benefit from the development of PCR methods

Please answer this: Extract the answer to the question from the following context. Question: Why did the leader of the Liadong territory had to seek allies to fight a potential power army? Context: Relocating his court from Jianzhou to Liaodong provided Nurhachi access to more resources; it also brought him in close contact with the Khorchin Mongol domains on the plains of Mongolia. Although by this time the once-united Mongol nation had long since fragmented into individual and hostile tribes, these tribes still presented a serious security threat to the Ming borders. Nurhachi's policy towards the Khorchins was to seek their friendship and cooperation against the Ming, securing his western border from a powerful potential enemy.
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Answer: hostile tribes, these tribes still presented a serious security threat to the Ming borders

Please answer this: Extract the answer to the question from the following context. Question: What might be a goal of Fourdrinier Machine? Context: All paper produced by paper machines as the Fourdrinier Machine are wove paper, i.e. the wire mesh that transports the web leaves a pattern that has the same density along the paper grain and across the grain. Textured finishes, watermarks and wire patterns imitating hand-made laid paper can be created by the use of appropriate rollers in the later stages of the machine.
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Answer:
imitating hand-made laid paper