Optical net gain measurement on Al0.07Ga0.93N/GaN multi-quantum wells.

We report net gain measurements at room temperature in Al0.07Ga0.93N/GaN 10-period multi-quantum well layers emitting at 367 nm, using the variable stripe length method. The separate confinement heterostructure was designed targeting electron-beam pumped lasing at 10 kV. The highest net gain value was 131 cm-1, obtained at the maximum pumping power density of the experimental setup (743 kW/cm2). The net gain threshold was attained at 218 kW/cm2 using 193 nm optical pumping. From these experiments, we predict an electron-beam-pumped lasing threshold of 370 kW/cm2 at room temperature, which is compatible with the use of compact cathodes (e.g. carbon nanotubes). In some areas of the sample, we observed an anomalous amplification of the photoluminescence intensity that occurs for long stripe lengths (superior to 400 µm) and high pumping power (superior to 550 kW/cm2), leading to an overestimation of the net gain value. We attribute such a phenomenon to the optical feedback provided by the reflection from cracks, which were created during the epitaxial growth due to the strong lattice mismatch between different layers.

Cutaneous Manifestations of Nutritional Deficiencies in the Context of Food Deserts of United States.

Food deserts exist due to a multitude of factors ranging from socioeconomic status, racial disparities, geography, cost, and healthful food access. Given the vast biological function of vitamins and minerals, the clinical presentation for nutritional deficiencies ranges from benign to life-threatening. Often, the first indicators of underlying nutritional deficiencies are cutaneous manifestations. The first patient case is a 36-year-old female at 25 weeks gestation with a pruritic and painful rash that began in the genital region and spread centrifugally to her legs. The second patient case is a 42-year-old male with a pruritic rash that began at his abdomen and progressed to his thighs. The third patient case is a 48-year-old female with scattered lower extremity ecchymoses in different healing stages and scattered perifollicular erythema with corkscrew hairs. All three patients were found to have nutritional deficiencies and lived in identified food deserts. Deficiencies of zinc, vitamin A, thiamine, pyridoxine, and vitamin C and their subsequent cutaneous manifestations have scarce documentation within food deserts. These cases provide further insight into nutritional deficiencies and offer an opportunity for providers to identify patients at risk. To promote wellness, patients suffering from food insecurity must be identified efficiently and connected with essential resources.

AlGaN/GaN asymmetric graded-index separate confinement heterostructures designed for electron-beam pumped UV lasers.

We present a study of undoped AlGaN/GaN separate confinement heterostructures designed to operate as electron beam pumped ultraviolet lasers. We discuss the effect of spontaneous and piezoelectric polarization on carrier diffusion, comparing the results of cathodoluminescence with electronic simulations of the band structure and Monte Carlo calculations of the electron trajectories. Carrier collection is significantly improved using an asymmetric graded-index separate confinement heterostructure (GRINSCH). The graded layers avoid potential barriers induced by polarization differences in the heterostructure and serve as strain transition buffers which reduce the mosaicity of the active region and the linewidth of spontaneous emission.

Nephrogenic Systemic Fibrosis in the Setting of Transient Renal Insufficiency.

Nephrogenic systemic fibrosis (NSF) is a rare disease that can present in patients with kidney injury who have been exposed to gadolinium-based contrast agents (GBCAs). These patients can easily be misdiagnosed as having another disease because they do not fit the usual presentation of being on hemodialysis. We report a case of NSF occurring in a patient with resolved transient renal insufficiency and no history of chronic renal disease.

Acroangiodermatitis of Mali and Stewart-Bluefarb syndrome.

Acroangiodermatitis (AAD), also known as pseudo-Kaposi sarcoma, is a rare benign vascular proliferation mainly of the extremities. It is characterized by violaceous patches or plaques resembling Kaposi sarcoma. The term pseudo-Kaposi sarcoma encompasses 2 variants of acroangiodermatitis: Mali type and Stewart-Bluefarb syndrome (SBS). Mali-type AAD is more common and is associated with chronic venous hypertension, while SBS is more rare and is associated with arteriovenous malformations and iatrogenic arteriovenous fistulae. We report 2 patients, representing each type of AAD.

Relapsing polychondritis in human immunodeficiency virus.

Relapsing polychondritis (RP) is an inflammatory condition that has been widely accepted as autoimmune in nature and can occur in patients with immune system dysregulation. Although RP has been well documented in patients with other autoimmune conditions, such as vasculitis, its presence in patients with human immunodeficiency virus (HIV) infection has been infrequently described. We describe a case of RP in an HIV-positive patient without other identifiable autoimmune disease.

Necrobiosis lipoidica with superimposed pyoderma vegetans.

Necrobiosis lipoidica (NL) is a granulomatous inflammatory skin disease strongly associated with diabetes mellitus (DM). Red-brown papules expanding into plaques with erythematous indurated borders on the lower extremities are characteristic of NL. Diagnosis is made clinically; however, biopsy of lesions confirms the diagnosis. Untreated NL may ulcerate and lead to further complications, but progression to superimposed pyoderma vegetans (PV) is not a known occurrence.

Psychic Song and Dance: Dissociation and Duets in the Analysis of Trauma.

The author offers observations on the nature of pathological dissociation, emphasizing the compartmentalization of unsymbolized affective experience. The irrelevance of personal agency and intentionality in the pathogenesis of dissociative psychopathology along with the deficiency in symbolization that is a sequela of trauma present special problems for traditional as well as for Relational approaches to technique. To a significant extent, "technique" must be replaced by the analyst's way of being. The author posits, as metaphor and model for this way of being, a notion of "psychoanalytic duets" occurring in the realms of both prosody and action-song and dance. An extended clinical vignette is presented to illustrate these ideas and to point toward a transformational effect of this kind of duetting.

Acrokeratoelastoidosis and knuckle pads coexisting in a child.

Acrokeratoelastoidosis (AKE) is a marginal papular keratoderma that typically presents in childhood and young adulthood. Childhood cases have exhibited autosomal-dominant inheritance. Acrokeratoelastoidosis is distinct from other palmoplantar marginal papular keratodermas because of its characteristic dermal elastorrhexis with an overlying epithelial dell. We report an 11-year-old boy with multiple translucent hyperkeratotic papules in a linear fashion on the bilateral palmoplantar surfaces characteristic of AKE. He also presented with knuckle pads on the proximal and distal interphalangeal joints that rarely have been reported with AKE, suggesting that AKE and atraumatic knuckle pads may coexist.

Inflammatory linear verrucous epidermal nevus responsive to 308-nm excimer laser treatment.

Inflammatory linear verrucous epidermal nevus (ILVEN) is a rare cutaneous disease that presents as linear psoriasiform plaques with associated prominent pruritus. The lesions commonly pre-sent on the legs with onset during childhood. Inflammatory linear verrucous epidermal nevus typically is refractory to treatment. Therapies range from topical treatments to lasers and surgical options. It is clinically and histopathologically similar to psoriasis, suggesting it may respond to established psoriasis treatments such as the excimer laser. We report the case of an otherwise healthy 20-year-old woman with dry, pruritic, red lesions on the right leg that had been present since infancy. Biopsy revealed psoriasiform hyperplasia with a verruciform surface. Multiple topical treatments including ablative CO2 laser therapy showed no remarkable improvement. The patient was then treated with a UV 308-nm excimer laser and showed noticeable clinical improvement. Because of its clinical and histopathological similarities to psoriasis, we hypothesized that the excimer laser may be useful in the treatment of these lesions.

Eosinophilic pustular folliculitis with underlying mantle cell lymphoma.

Eosinophilic pustular folliculitis (EPF) is a noninfectious condition characterized by folliculocentric papules, pustules, and plaques on the head, trunk, and extremities. Three subtypes of EPF have been described. Histopathology predominantly shows abundant eosinophils concentrated at the follicle, and treatment typically consists of topical corticosteroids or oral indomethacin. We present an unusual case of EPF in a 52-year-old man that preceded the diagnosis of mantle cell lymphoma.

Spontaneous regression of Merkel cell carcinoma.

A 96-year-old woman presented with a rapidly enlarging lesion overlying the suprasternal notch. The lesion originated as a small, erythematous, scaly macule that rapidly increased in size over 8 weeks and became an ulcerated nodule measuring 5 cm in diameter and 4.5 cm in thickness. A 4-mm punch biopsy showed a poorly differentiated tumor with cells that were positive for CAM 5.2 and cytokeratin 20 in a dotlike paranuclear pattern and negative for cytokeratin 5/6, human melanoma black 45, and leukocyte common antigen. Two weeks after the punch biopsy, the lesion noticeably decreased in size, and within 8 weeks of the biopsy the tumor had completely resolved with no further intervention. Regression of Merkel cell carcinoma (MCC) is a very rare event, with as few as 30 cases reported. The mechanism of this phenomenon remains unclear; however, T-cell-mediated immunity and apoptosis appear to play a major role.

Photosensitive atopic dermatitis exacerbated by UVB exposure.

Photosensitive atopic dermatitis (AD) is a rare disease entity that many physicians are not familiar with, thus it often is misdiagnosed. It can be life altering, as patients often strictly avoid the sun and may only leave the house at night. Effective treatments are available, and therefore diagnosis is key to improve quality of life for these patients. We describe a case of photosensitive AD exacerbated by UVB exposure. The diagnosis was made with phototesting, and the patient was able to begin treatment with narrowband UVB (NB-UVB) hardening while on immunosuppression. The literature on photosensitive AD is limited, and this entity typically is not found in the main dermatology textbooks. Our case emphasizes the diagnostic problems and complexity of photosensitive AD. Histopathologic findings are nonspecific. A thorough history and physical examination can provide the necessary clues for further workup. Phototesting should be performed to confirm the diagnosis and evaluate the degree of sensitivity to UV light and the specific wavelength eliciting the cutaneous response. Photoprovocation and photopatch testing also can be useful to confirm the diagnosis.

Muckle-Wells syndrome in the setting of basal cell nevus syndrome.

Muckle-Wells syndrome (MWS) is a rare disorder inherited in an autosomal-dominant fashion that belongs to a group of hereditary periodic fever syndromes. It specifically belongs to the cryopyrin-associated periodic syndromes (CAPSs) in which there is a mutation in the NLRP3 (NLR family pyrin domain containing 3) gene that leads to overproduction of IL-1ß, the source of the multisystem inflammatory symptoms. Muckle-Wells syndrome is characterized by a recurrent urticarial eruption that is associated with episodic fever, myalgia, arthralgia, malaise, progressive sensorineural hearing loss, and amyloid nephropathy (the most severe complication). Basal cell nevus syndrome (BCNS), or Gorlin syndrome, is a rare, autosomal-dominant inherited genodermatosis linked to a mutation in the PTCH1 (patched 1) gene and is characterized by a broad range of anomalies. We report the case of a patient with MWS and BCNS in whom basal cell carcinoma (BCC) treatment was complicated by symptoms of MWS.