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A diagnostic for extreme ultraviolet spectroscopy was fielded on the sheared-flow-stabilized (SFS) fusion Z-pinch experiment (FuZE-Q) for the first time. The spectrometer collected time-gated plasma emission spectra in the 5-40 nm wavelength (30-250 eV) range for impurity identification, radiative power studies, and for plasma temperature and density measurements. The unique implementation of the diagnostic included fast (10 ns risetime) pulsed high voltage electronics and a multi-stage differential pumping system that allowed the vacuum-coupled spectrometer to collect three independently timed spectra per FuZE-Q shot while also protecting sensitive internal components. Analysis of line emission identifies oxygen (N-, C-, B-, Be-, Li-, and He-like O), peaking in intensity shortly after maximum current (>500 kA). This work provides a foundation for future high energy spectroscopy experiments on SFS Z-pinch devices.

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Using three-dimensional (3D) magnetohydrodynamic simulations, we study how a pit on a metal surface evolves when driven by intense electrical current density j. Redistribution of j around the pit initiates a feedback loop: j both reacts to and alters the electrical conductivity σ, through Joule heating and hydrodynamic expansion, so that j and σ are constantly in flux. Thus, the pit transforms into larger striation and filament structures predicted by the electrothermal instability theory. Both structures are important in applications of current-driven metal: The striation constitutes a density perturbation that can seed the magneto-Rayleigh-Taylor instability, while the filament provides a more rapid path to plasma formation, through 3D j redistribution. Simulations predict distinctive self-emission patterns, thus allowing for experimental observation and comparison.

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Electrothermal instability plays an important role in applications of current-driven metal, creating striations (which seed the magneto-Rayleigh-Taylor instability) and filaments (which provide a more rapid path to plasma formation). However, the initial formation of both structures is not well understood. Simulations show for the first time how a commonly occurring isolated defect transforms into the larger striation and filament, through a feedback loop connecting current and electrical conductivity. Simulations have been experimentally validated using defect-driven self-emission patterns.

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A direct observation of the stratified electrothermal instability on the surface of thick metal is reported. Aluminum rods coated with 70µm Parylene-N were driven to 1 MA in 100ns, with the metal thicker than the skin depth. The dielectric coating suppressed plasma formation, enabling persistent observation of discrete azimuthally correlated stratified thermal perturbations perpendicular to the current whose wave numbers, k, grew exponentially with rate γ(k)=0.06ns^{-1}-(0.4ns^{-1}µm^{2}rad^{-2})k^{2} in ∼1g/cm^{3}, ∼7000K aluminum.

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Pectinate ligament dysplasia (PLD) is a common cause of canine glaucoma and the definitive clinical diagnosis is based on gonioscopy. Although the histologic lesions of PLD have been described, it has not been determined whether these changes are specific for PLD or if similar histologic changes can develop as a consequence of secondary glaucoma. The filtration angles of 61 enucleated canine globes with chronic glaucoma were evaluated with light microscopy by 3 examiners who were masked to the clinical history, signalment, and gonioscopic results. A histologic diagnosis of PLD versus non-PLD was determined by each examiner based on previously reported morphologic criteria and compared with the clinical gonioscopic diagnosis. Of the 61 enucleated glaucomatous eyes, 40 were clinically diagnosed with PLD. For all 3 examiners, a histologic diagnosis of PLD corresponded poorly with the clinical diagnosis of PLD (range of kappa score: 0.149-0.269; range of AUC: 0.592-0.621). There was no difference between examiners in their ability to correctly diagnose PLD histologically (P = .978). A fair degree of agreement was noted among examiners in obtaining their suspected histologic diagnosis of PLD (kappa score 0.256). No individual or sets of histologic ICA features were consistent with clinical PLD. The results indicate the histologic ICA changes proposed to be characteristic of PLD are also noted in canine globes affected with chronic secondary glaucoma. Therefore, using routine histologic evaluation, a histologic diagnosis of PLD is not possible in the face of chronic canine glaucoma.

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The first measurement of the threshold for thermal ionization of the surface of thick metal by pulsed magnetic field (B) is reported. Thick aluminum-with depth greater than the magnetic skin layer-was pulsed with partial differential B/ partial differential t from 30-80 MG/micros. Novel loads avoided nonthermal plasma (from electron avalanche, or energetic particles or photons from arcs). Thermal plasma forms from 6061-alloy aluminum when the surface magnetic field reaches 2.2 MG, in qualitative agreement with numerical simulation results by Garanin et al. [J. Appl. Mech. Tech. Phys. 46, 153 (2005)].

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Radiation magnetohydrodynamic modeling is used to study the plasma formed on the surface of a cylindrical metallic load, driven by megagauss magnetic field at the 1MA Zebra generator (University of Nevada, Reno). An ionized aluminum plasma is used to represent the "core-corona" behavior in which a heterogeneous Z-pinch consists of a hot low-density corona surrounding a dense low-temperature core. The radiation dynamics model included simultaneously a self-consistent treatment of both the opaque and transparent plasma regions in a corona. For the parameters of this experiment, the boundary of the opaque plasma region emits the major radiation power with Planckian black-body spectrum in the extreme ultraviolet corresponding to an equilibrium temperature of 16 eV. The radiation heat transport significantly exceeds the electron and ion kinetic heat transport in the outer layers of the opaque plasma. Electromagnetic field energy is partly radiated (13%) and partly deposited into inner corona and core regions (87%). Surface temperature estimates are sensitive to the radiation effects, but the surface motion in response to pressure and magnetic forces is not. The general results of the present investigation are applicable to the liner compression experiments at multi-MA long-pulse current accelerators such as Atlas and Shiva Star. Also the radiation magnetohydrodynamic model discussed in the paper may be useful for understanding key effects of wire array implosion dynamics.

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Inflammatory linear verrucous epidermal nevus (ILVEN) is a benign cutaneous hamartoma characterized by intensely erythematous, pruritic, inflammatory papules that occur as linear bands along the lines of Blaschko. Because of its chronic and unremitting symptomatology, patients with ILVEN seek medical treatment for relief of discomfort as well as concerns regarding cosmetic appearance. Reported therapeutic approaches include topical agents, dermabrasion, cryotherapy, laser therapy, and partial-thickness excision. Unfortunately, no one therapy has been successful consistently. Medical management is often unsatisfactory, because improvement tends to be temporary. Surgical modalities have met with better success in relief of symptoms but at the risk of marked scarring and a high rate of recurrence. Furthermore, the occurrence of extensive ILVEN or localization to certain anatomic regions has been considered previously a relative contraindication to excision. The authors report 4 patients with extensive ILVEN treated successfully with full-thickness surgical excision. Our report underscores the effectiveness of this surgical modality for the definitive treatment of ILVEN.

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The authors present a cohort of 21 consecutive patients who had congenital pigmented nevi covering 15 to 65 percent of the forehead and adjacent scalp and who were treated at their institution within the last 12 years. All patients were treated with an expansion of the adjacent texture- and color-matched skin as the primary modality of treatment. The median age at presentation was approximately 1 year; mean postoperative follow-up was 4 years. Nevi were classified according to the predominant anatomic areas they occupied (temporal, hemiforehead, and midforehead/central); some of the lesions involved more than one aesthetic subunit. The authors propose the following guidelines: (1) Midforehead nevi are best treated using an expansion of bilateral normal forehead segments and advancement of the flaps medially, with scars placed along the brow and at or posterior to the hairline. (2) Hemiforehead nevi often require serial expansion of the uninvolved half of the forehead to minimize the need for a back-cut to release the advancing flap. (3) Nevi of the supraorbital and temporal forehead are preferentially treated with a transposition of a portion of the expanded normal skin medial to the nevus. (4) When the temporal scalp is minimally involved with nevus, the parietal scalp can be expanded and advanced to create the new hairline. When the temporoparietal scalp is also involved with nevus, a transposition flap (actually a combined advancement and transposition flap because the base of the pedicle moves forward as well) provides the optimal hair direction for the temporal hairline and allows significantly greater movement of the expanded flap, thereby minimizing the need for serial expansion. (5) Once the brow is significantly elevated on either the ipsilateral or contralateral side from the reconstruction, it can only be returned to the preoperative position with the interposition of additional, non-hair-bearing forehead skin. Expansion of the deficient area alone will not reliably lower the brow once a skin deficiency exists. (6) In general, one should always use the largest expander possible beneath the uninvolved forehead skin, occasionally even carrying the expander under the lesion. Expanders are often overexpanded.

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A congenital peripheral primitive neuroectodermal tumor of the hand demonstrating aggressive behavior by rapid growth and ulceration, as well as early diffuse metastasis is presented. Management consisted of below-elbow amputation and chemotherapy. Despite the tumor's initial response, intracranial metastases occurred 7 months later. The patient died shortly thereafter, 15 months after presentation.

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Nevomelanocytic lesions in children represent a wide spectrum of proliferative neurocristopathies, ranging from the common small and benign congenital nevi to the garment-type congenital lesions. Included in this spectrum are some rare entities like neurocutaneous melanocytosis, malignant melanoma simulants, and special variants of congenital pigmented nevi. Here, we analyze some tissue culture characteristics of nevomelanocytic cells from giant and small congenital nevi, neurocutaneous melanocytosis, and a rare variant of nevus named "bulky nevocytoma." Correlations with their histological, immunohistochemical, and ultrastructural features are addressed.

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Kindler syndrome is a rare, blistering skin disease characterized by acral bullae, poikiloderma, and diffuse cutaneous atrophy. Kindler syndrome has been established as a separate entity from epidermolysis bullosa; however, controversy still remains as to whether Kindler syndrome can be differentiated from Weary's hereditary acrokeratotic poikiloderma. Fusion of the digits secondary to blistering and scarring, "pseudosyndactyly," has been reported in several patients with Kindler syndrome; however, surgical correction of the syndactylies in these patients has not been described. In this report, a patient with Kindler syndrome underwent surgical treatment of acquired syndactylies. Treatment included a tailored approach to preparation of the patient for surgery, surgical separation of fused tissues, selection of donor site for skin-graft harvest, postoperative dressings, splinting, and therapy. Results in our patient 2 years after correction demonstrate that syndactyly release in Kindler syndrome can be accomplished effectively, with improvement in both function and appearance.

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It is important for clinicians to consider lymphatic malformations in the differential diagnosis of chronic skin lesions, no matter where they appear anatomically. We report a case of deep surgical excision of an extensive lymphatic malformation of the scrotum using regional flaps from uninvolved scrotal tissue. Removal of the lesion not only allowed the patient more comfort but also may have ultimately cured his symptomatology.

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Since our initial presentation of our experience with tissue expansion as a means of harvesting large full-thickness skin grafts in children in 1987, we have continued to "expand" both the size of full-thickness skin grafts harvested and the range of reconstructive problems to which we have applied the technique. Sixteen expanded full-thickness grafts have been used for immediate reconstruction following giant nevus excision and in postburn reconstruction. Patients ranged in age from 6 months to 15 years, with follow-up ranging from 6 months to 6 1/2 years. Grafts ranging in size from approximately 60 cm2 (excluding the dimensions of one submental graft) to greater than 700 cm2 were harvested from expanded donor sites on unilateral or bilateral groin/lower abdomen, clavicular, and a single submental expansion. Five expanded full-thickness grafts were used in facial reconstruction for single aesthetic unit coverage, multiple unit, and one single-sheet full facial graft. One expanded full-thickness graft was used on the breast. Three grafts were used in dorsal hand and finger coverage, and seven were used on the lower extremity, including an entire plantar surface and toes. Graft loss was confined to a 6.25-cm2 area on one cheek in the full facial expanded full-thickness grafts and a 9-cm2 area on the non-weight-bearing area of the full plantar graft. Donor-site complications were negligible. The anatomic confines of the donor sites and size of the patient may require expander replacement (in situ serial expansion) in order to obtain a large enough graft and accomplish primary donor-site closure. Expander and injection port placement in children for ease of injection and planned expander change must be anticipated. Our protocol from preoperative teaching through graft take is reviewed. Experience has demonstrated that expanded full-thickness grafts maintain all the characteristics of non-expanded full-thickness skin grafts and are an excellent reconstructive option in children.

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Nevus comedonicus is a rare developmental abnormality of the pilosebaceous apparatus that presents as an aggregation of dilated follicular orifices filled with pigmented keratinous material. Occurrence of extensive or giant lesions is even more rare. Indications for treatment include recurrent infections and cosmetic reasons. Therapeutic approaches include topical keratolytic agents, manual extraction of comedones, dermabrasion, and excision of smaller lesions. Increasing clinical experience with tissue expansion has suggested that it might be used effectively in the definitive treatment of an extensive nevus comedonicus previously considered too large to excise without the use of a skin graft, despite the potential risk of infection within the lesion during the course of expansion. We report the first patient with giant nevus comedonicus to be treated using tissue expansion. This patient demonstrates that prompt treatment of cellulitis and abscesses within the lesion will keep this process isolated from the adjacent expanders and will not compromise a planned excision and reconstruction.

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We describe two instances of a previously unrecognized variant of congenital giant pigmented naevus (GPN), presenting as a bulky naevocytic tumour in the perineal region. In both cases the lesion was present at birth and attained massive dimensions. In addition to the characteristic histological patterns found in GPN, which included extensive areas with a neural appearance, these tumours presented an uncommon tendency to form pseudo-follicular structures lined by naevus cells. No features suggestive of malignant transformation were found. Because GPN may associate with an underlying malignancy, accurate diagnosis of this lesion is important in clinical practice.

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Miller's syndrome is a rare congenital disorder with facial features similar to that of Treacher-Collins syndrome. This report details the anaesthetic management of an infant during multiple surgical procedures, beginning with pylormyotomy at one month of age. Airway management was difficult because of severe micrognathia and was accomplished using an awake intubation with a conventional straight blade modified for continuous administration of oxygen ("oxyscope"). Due to recurrent upper airway obstruction and the anticipated need for multiple surgical procedures in the first years of life, a tracheostomy was placed. Because of the multiple airway, orthopaedic, and nutritional difficulties, it is important that a prospective, multidisciplinary approach be used in these patients' care. Consideration should be given to early tracheostomy for airway maintenance.

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The following guidelines are suggested for the use of tissue expansion in ear reconstruction based on both personal experience and my evaluation of the reported results of expansion in the hands of other surgeons experienced in ear reconstruction: 1) Cases should be carefully selected to avoid those with excess scarring from previous surgery or trauma as well as avoid the other common contraindications to the use of tissue expansion. 2) In most congenital cases the expander should be placed through a remote incision within the postauricular hairline, and excision of the cartilage vestige delayed until expansion is completed and the framework is ready for placement. 3) A remote valve expander of a crescent shape with a volume of 60-100cc is ideal; low profile expanders may even be safer. 4) The pocket for the expander should be dissected immediately above the fascia and against the cartilage remnant. 5) Rapid expansion should be avoided; ideally injections should be carried out one time each week and with relatively small quantities (5-10cc per injection). 6) At the time of expander removal and placement of the cartilage framework the capsule should be meticulously excised to allow tight skin-cartilage coaptation. This is further enhanced by effective suction drainage following wound closure.

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The ability to increase available local tissue by controlled soft tissue expansion (TE) has led to a rapid increase in the use of TE in clinical practice. This article reviews some general guidelines when using TE in children and addresses some of the concerns previously expressed regarding the effects of TE on growth in infants and children.

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Airway patency following repair for choanal atresia is effectively maintained utilizing Argyle polyethylene chest tubes as stents. Retrograde placement of the tubes from the mouth into the nasal passage is accomplished so that once secured, the largest diameter of the tubes is wedged against the posterior portion of the nasal ostium. This approach limits anterior migration of the tubes, preserving the columella and nasal rims while ensuring maintenance of airway patency following treatment of choanal atresia.

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