Beyonce Knowles’ studious ascension from first lady of contemporary R&B to mononymous multitalent has been ongoing for the better part of a decade, but somewhere in the past 12 months, she seems to have crossed an important threshold.Perhaps it was her keynote performance at Barack Obama’s inaugural ball, the upward of $70 million made by her film vehicle “Obsessed,” the ubiquity of “Single Ladies (Put a Ring on It)” and its endlessly mimicked video, or the fact that, according to Forbes, she’s now the highest-paid star under 30. Whatever the moment may have been, the Houston native has clearly moved into the uppermost echelon of crossover stars. Clearly, she’s never made a secret of her own ambition. In fact, it’s an integral element of her persona. “I consider myself a strong woman who believes in hard work and determination,” she says simply. Knowles’ unique mixture of sophistication, controlled sex appeal and chip-on-the-shoulder female empowerment has been refined down to a science in recent years, evolving from the Aretha-like sass of early Destiny’s Child single “Bills, Bills, Bills” to the feminist ferocity of later efforts like last year’s “Diva” and 2006′s truly vicious “Irreplaceable.” Appropriately enough, her recent arena tour has featured zero Y chromosomes onstage. “I think it’s great for women to support each other and believe in themselves and what they can do as women,” she says. “What better way to show that live than having an all-female band?” While simply maintaining her personal brand would seem a tall enough order, Knowles has nonetheless begun to branch out in subtle, yet significant ways. Limning Etta James in 2008′s “Cadillac Records” was a risk, and psychological thriller “Obsessed” marked Knowles’ first film role that was neither a comedy nor a musical. “I feel like dramatic roles suit me best,” she says, though she also notes: “My dream role is playing a dark and sexy superhero.” Beyonce the superhuman — perhaps that’s the next threshold. IN A NUTSHELL Job titles: Singer, songwriter, actress, model, producer Inspirations: “Michael Jackson, Tina Turner, Barbra Streisand, my mother, the list could go on and on. I am inspired by people who break barriers, who work hard and show greatness from their heart.” Career mantra: “Believe in yourself, work hard and practice.” Philanthropic passions: Knowles is a founder of the Survivor Foundation, which assists victims of disasters, homelessness and AIDS, as well as a supporter of Feeding America and Make-A-Wish.