Damage areas on selected LDEF aluminum surfaces

With the U.S. about to embark on a new space age, the effects of the space environment on a spacecraft during its mission lifetime become more relevant. Included among these potential effects are degradation and erosion due to micrometeoroid and debris impacts, atomic oxygen and ultraviolet light exposure as well as material alteration from thermal cycling, and electron and proton exposure. This paper focuses on the effects caused by micrometeoroid and debris impacts on several LDEF aluminum plates from four different bay locations: C-12, C-10, C-01, and E-09. Each plate was coated with either a white, black, or gray thermal paint. Since the plates were located at different orientations on the satellite, their responses to the hypervelocity impacts varied. Crater morphologies range from a series of craters, spall zones, domes, spaces, and rings to simple craters with little or no spall zones. In addition, each of these crater morphologies is associated with varying damage areas, which appear to be related to their respective bay locations and thus exposure angles. More than 5% of the exposed surface area examined was damaged by impact cratering and its coincident effects (i.e., spallation, delamination and blow-off). Thus, results from this analysis may be significant for mission and spacecraft planners and designers

A Guyon's canal ganglion presenting as occupational overuse syndrome: A case report

<p>Abstract</p> <p>Background</p> <p>Occupational overuse syndrome (OOS) can present as Guyon's canal syndrome in computer keyboard users. We report a case of Guyon's canal syndrome caused by a ganglion in a computer user that was misdiagnosed as OOS.</p> <p>Case presentation</p> <p>A 54-year-old female secretary was referred with a six-month history of right little finger weakness and difficulty with adduction. Prior to her referral, she was diagnosed by her general practitioner and physiotherapist with a right ulnar nerve neuropraxia at the level of the Guyon's canal. This was thought to be secondary to computer keyboard use and direct pressure exerted on a wrist support. There was obvious atrophy of the hypothenar eminence and the first dorsal interosseous muscle. Both Froment's and Wartenberg's signs were positive. A nerve conduction study revealed that both the abductor digiti minimi and the first dorsal interosseus muscles showed prolonged motor latency. Ulnar conduction across the right elbow was normal. Ulnar sensory amplitude across the right wrist to the fifth digit was reduced while the dorsal cutaneous nerve response was normal. Magnetic resonance imaging of the right wrist showed a ganglion in Guyon's canal. Decompression of the Guyon's canal was performed and histological examination confirmed a ganglion. The patient's symptoms and signs resolved completely at four-month follow-up.</p> <p>Conclusion</p> <p>Clinical history, occupational history and examination alone could potentially lead to misdiagnosis of OOS when a computer user presents with these symptoms and we recommend that nerve conduction or imaging studies be performed.</p

Three-dimensional laser surface imaging and geometric morphometrics resolve frontonasal dysmorphology in schizophrenia.

BACKGROUND: Although a role for early developmental disturbance(s) in schizophrenia is postulated, it has proved difficult to identify hard, biological evidence. The brain and face emerge in embryologic intimacy, such that in neurodevelopmental disorders, brain dysmorphogenesis is accompanied by facial dysmorphogenesis. METHODS: Three-dimensional (3D) laser surface imaging was used to capture the facial surface of patients and control subjects in 37 male and 32 female patients who satisfied DSM-IV criteria for schizophrenia in comparison with 58 male and 34 female control subjects. Surface images were analyzed using geometric morphometrics and 3D visualizations to identify domains of facial shape that distinguish patients from control subjects. RESULTS: Both male and, particularly, female patients evidenced significant facial dysmorphology. There was narrowing and reduction of the mid to lower face and frontonasal prominences, including reduced width and posterior displacement of the mouth, lips, and chin; increased width of the upper face, mandible, and skull base, with lateral displacement of the cheeks, eyes, and orbits; and anterior displacement of the superior margins of the orbits. CONCLUSIONS: The frontonasal prominence, which enjoys the most intimate embryologic relationship with the anterior brain and also orchestrates aspects of development in maxillary and mandibular domains, evidences a characteristic topography of dysmorphogenesis in schizophrenia

Sensor Integrated Metal Dielectric Filters for Solar-Blind Silicon Ultraviolet Detectors

A filter for electromagnetic radiation including one or more dielectric spacer regions and one or more reflective regions integrated on a semiconductor substrate, the semiconductor substrate including a semiconductor photodetector, such that the filter transmits ultraviolet radiation to the semiconductor photodetector, the ultraviolet radiation having a range of wavelengths, and the filter suppresses transmission of electromagnetic radiation, having wavelengths outside the range of wavelengths, to the semiconductor photodetector

The development and application of metal-catalyzed processes for organic synthesis

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2005.Vita.Includes bibliographical references.Chapter 1. Copper-Catalyzed Arylation of Stabilized Carbanions A mild, general catalytic system for the synthesis of [alpha]-aryl malonates has been developed. Aryl iodides bearing a variety of functional groups can be effectively coupled to diethyl malonate in high yields using inexpensive and widely available reagents, making this a superior method to those previously described that employ copper reagents or catalysts. The functional group tolerance of the process developed makes it complementary to analogous palladium-catalyzed couplings. Importantly, a set of mild reaction conditions has been developed that minimize product decomposition, a problem that had not been addressed previously in the literature. In addition, the utilization of aryl bromides as coupling partners has been investigated, as well as the use of other classes of nucleophilic stabilized carbanions. Chapter 2. Synthesis of Oxindoles from a-Haloacetanilides via Palladium-Catalyzed C-H Functionalization We have discovered a palladium-catalyzed reaction that efficiently produces oxindoles from a-haloacetanilides through a net functionalization of an arene C-H bond. The high levels of regioselectivity observed in this cyclization obviate the need for highly functionalized aromatic substrates to effect desired ring closure. Moreover, the breadth of functional groups compatible with the reaction conditions is vastly greater than that of analogous Lewis acid-mediated processes. Extensive mechanistic work has been conducted, including kinetic isotope effect and linear free energy relationship studies.(cont.) A number of plausible pathways are consistent with our data and with previously published examples of palladium-catalyzed C-H functionalization processes. Chapter 3. Synthesis of DAPHAnalogs via Palladium-Catalyzed Amination DAPH (4,5-dianilinophthalimide) has previously been shown to reverse the formation of neurotoxic fibrils associated with Alzheimer's disease. We have developed a synthetic route to DAPH and structurally-related analogs that employs palladium- catalyzed amination as the key bond-forming step. The requisite substrates are easily obtained, and their coupling with substituted anilines proceeds in generally high yields. Thus, a variety of DAPH analogs can be quickly accessed in a modular fashion. In addition, the route described herein should also be amenable to the incorporation of other classes of nucleophiles into the molecular framework. The results of biological assays conducted thus far will serve as a guide for further lead optimizationby Edward J. HennessyPh.D

Human Factors Certification of Advanced Aviation Technologies

Proceedings of the Human Factors Certification of Advanced Aviation Technologies Conference held at the Chateau de Bonas, near Toulouse, France, 19-23 July 1993

Climate change and health effects in Northwest Alaska

This article provides examples of adverse health effects, including weather-related injury, food insecurity, mental health issues, and water infrastructure damage, and the responses to these effects that are currently being applied in two Northwest Alaska communities