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A traditional quantum optimal control experiment begins with a specific physical system and seeks an optimal time-dependent field to steer the evolution towards a target observable value. In a more general framework, the Hamiltonian structure may also be manipulated when the material or molecular 'stockroom' is accessible as a part of the controls. The current work takes a step in this direction by considering the converse of the normal perspective to now start with a specific fixed field and employ the system's time-independent Hamiltonian structure as the control to identify an optimal form. The Hamiltonian structure control variables are taken as the system energies and transition dipole matrix elements. An analysis is presented of the Hamiltonian structure control landscape, defined by the observable as a function of the Hamiltonian structure. A proof of system controllability is provided, showing the existence of a Hamiltonian structure that yields an arbitrary unitary transformation when working with virtually any field. The landscape analysis shows that there are no suboptimal traps (i.e., local extrema) for controllable quantum systems when unconstrained structural controls are utilized to optimize a state-to-state transition probability. This analysis is corroborated by numerical simulations on model multilevel systems. The search effort to reach the top of the Hamiltonian structure landscape is found to be nearly invariant to system dimension. A control mechanism analysis is performed, showing a wide variety of behavior for different systems at the top of the Hamiltonian structure landscape. It is also shown that reducing the number of available Hamiltonian structure controls, thus constraining the system, does not always prevent reaching the landscape top. The results from this work lay a foundation for considering the laboratory implementation of optimal Hamiltonian structure manipulation for seeking the best control performance, especially with limited electromagnetic resources.

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Cosmetic alteration of a patient's orbital skin is a common reason for professional consultation. This review presents the differential diagnosis and recommended evaluation of inflamed eyelids. To better understand the diseases, each is individually addressed clinically, pathogenetically, and therapeutically. It is critical to recognize the lesions correctly and to have full knowledge of the putative clinical disease process. An algorithm for an appropriate work-up for each disease is offered. With this background, a successful therapeutic response can be anticipated.

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Updating our clinical concept of atopic dermatitis (AD) evolves from the better understanding of all the immunologic aberrations expressed by the polygenic combinations and permutations associated with the atopic diathesis. Recognizing the immunopathologic features of AD readily underscores that AD without "atopy" is an oxymoron. Appreciating "pruritus" as the impetus to scratch, which isomorphically gives rise to the "eczema," shifts the goal of management from suppressing inflammation to avoiding the triggers of pruritus. Recognizing the full spectrum of dermatologic findings in AD endorses the preferred label as a dermatitis, rather than the inferred restrictive label, atopic eczema. As our knowledge of immunology evolves, our criteria for the diagnosis and management of the atopic diathesis are sure to change.

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"Itchy" rashes occurring in patients (usually an infant or child) with a personal and/or family history of itching, sneezing, and/or wheezing should be considered part of the spectrum of skin problems labeled "atopic dermatitis" (AD). Multiple factors influence AD, and effective management requires that none be overlooked. The complicated nature of treatment means parents and family members require repeated reinforcement and education, particularly in avoiding "triggers of itch;" and use of medications. When all the aspects of AD are adequately addressed, more than 90% of patients with AD can be effectively managed.

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Defining "allergy" and elucidating the immunopathology of what is too often described as allergic rashes is the objective of this article. The differentiation of inflammatory reactions, which at times is indistinguishable from the immunologic dermatoses is outlined. A rationale plan for management, with indications warranting referral to "the specialist" are suggested.

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LEARNING OBJECTIVES: Reading this article will reinforce the reader's knowledge of the definition, pathophysiology, differential diagnosis, evaluation, and management of the most common of all the "eczemas," contact dermatitis, which can have an allergic and/or an irritant pathogenesis. DATA SOURCES: Relevant articles and current texts on contact dermatitis were referenced and reviewed. The personal experiences of the authors in an Environmental Medicine Clinic, their private practices, and their teaching of residents and other physicians were evaluated. A MEDLINE database using subject keywords was searched from 1986 to date. STUDY SELECTION: Book chapters, pertinent articles, data source abstracts, guidelines for the management of contact dermatitis set by the American Academy of Dermatology, and the American Contact Dermatitis Society were critiqued. RESULTS: The recent elucidation of the pathoimmunology of contact dermatitis is concisely reviewed, highlighting its clinical implications. The protean clinical presentations of contact dermatitis, both "allergic" and "irritant" type are cited. The signs and symptoms warranting the search for a contactant are outlined. The most likely regional contactants are listed, but the need to reference a more complete textbook is often required. That patch testing is the gold standard to identify an allergenic agent causing allergic contact dermatitis is stressed. While the "who" and "when" to patch test is amply described, a cookbook "how" to patch test has been omitted in order to emphasize the importance of "hands on" experience for such testing. The advantages and limitations of the commercially available standard patch tests (Hermal, and T.R.U.E.) are described, plus the sources for "nonstandard" patch tests is made available. Therapeutic modalities, topical and systemic, for management of the uncomfortable patient are outlined. CONCLUSION: The physician who manages a patient with an "eczematous" rash must be aware of the complete differential diagnosis of that clinical presentation. Suspicion that a "contactant" is the cause must have high priority, especially when the rash is persistent, and fails to respond to "appropriate" therapy. The value of a skin biopsy is limited to confirming its eczematous (spongiotic) nature and ruling out other diseases. Appreciating the paradox of patch testing, namely the deceptive simplicity of application versus the required expertise for interpretation and recognition of clinical significance, is the key to the proper management of the patient with contact dermatitis.

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This article discusses the allergist's or dermatologist's rational pathophysiologic approach to urticaria and angioedema. Every recognized cause is outlined and identified for preventing acute urticaria. Appreciating chronic urticaria as a "twitchy mast cell" syndrome is emphasized. The "art of pharmacologic" gymnastics is presented for the safest and most effective management of patients with urticaria.

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Urticaria, or hives, is a usually transient reaction involving the upper dermis. Understanding the causes and treatments of urticaria will help the dermatology nurse manage the patient with hives.

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Reactivation of Chagas' disease in immuno-compromised hosts may represent a recognizable clinical syndrome that can be diagnosed by examination of skin biopsy specimens of characteristic lesions resembling ordinary bacterial cellulitis. This syndrome appears to result in significant morbidity, which can be avoided with the institution of prophylactic therapy for Chagas' disease. An awareness of this complication of immunosuppression is of paramount importance for the thousands of asymptomatic persons infected with Chagas' disease currently living in the United States and abroad.

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We present the case of an otherwise healthy woman with noduloulcerative ("malignant") syphilis, the first female patient reported with this dermatosis in fifty years. This rare form of secondary syphilis is characterized by noduloulcerative lesions with rupioid crusts that dramatically involve the face while usually sparing the palms and soles. The aggression and destruction of the skin lesions may mimic that of other granulomatous and infiltrative dermatoses. Since the incidence of syphilis is increasing, physicians should be aware of this variant that is so disfiguring it has historically been referred to as lues maligna.

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