The phrase "a single difficulty" is correct and usable in written English.
It can be used when referring to one specific challenge or problem that someone is facing.
Example: "Despite the many obstacles in her path, she was determined to overcome a single difficulty that had been holding her back."
Alternatives: "one challenge" or "a solitary problem."
Perhaps the greatest single difficulty both face is steering a course between a descriptive and a normative definition of global civil society - between what is and what ought to be (or, perhaps, what they would like to be).
It added, "Baggage-handling has become perhaps the biggest single difficulty encountered by an air passenger".
The impresario, who made his name bringing intelligent, independent cinema to the masses, faces a multitude of problems, but they all boil down a single, intractable difficulty: he is struggling to produce and distribute enough intelligent, independent cinema that the popcorn-scoffing masses actually want to see.
Based on the analysis of this study, the themes "symptoms" and "adaptations" merged into a single domain ("difficulty").
In many cases, the introduction of a single sleep difficulty symptom was associated with a larger decrement in HRQoL among patients with FM, however, the introduction in a second sleep difficulty symptom was associated with larger decrement in HRQoL among matched controls.
In addition, sorafenib (at the standard dose of 400 mg BID) is tolerated poorly by ovarian cancer patients, even when used as a single agent; difficulties in adding sorafenib to combination chemotherapy have also been demonstrated in other diseases 22, 23.
Experiment 1 determined whether for BIOA, single vs. dual-task performance conditions led to similar effects as a single-task difficulty (congruent vs. incongruent) manipulation.
In this paper the optimal design of the exchanger has been formulated as a geometric programming with a single degree of difficulty.
The most straightforward generalization of this formula to the discrete version of the scatterer problem used in numerical computations does not allow the kernel to be inferred from a single numerical experiment a difficulty we call the multi-source problem.
In summary, the FNA-based sampling could present a unique set of diagnostic challenges, such as small amount of tumor cells, obscuring effect of tumor necrosis, the need to assess samples from different areas/multiple needle passes on a single slide and difficulty in quantifying the degree or extent of IHC staining.
