2,129 research outputs found
Quantum Monte Carlo for minimum energy structures
We present an efficient method to find minimum energy structures using energy
estimates from accurate quantum Monte Carlo calculations. This method involves
a stochastic process formed from the stochastic energy estimates from Monte
Carlo that can be averaged to find precise structural minima while using
inexpensive calculations with moderate statistical uncertainty. We demonstrate
the applicability of the algorithm by minimizing the energy of the H2O-OH-
complex and showing that the structural minima from quantum Monte Carlo
calculations affect the qualitative behavior of the potential energy surface
substantially.Comment: 7 pages, 4 figure
Computed tomographic appearance of urachal adenocarcinomas: review of 25 cases
Twenty-five cases of surgically proven urachal carcinomas were retrospectively reviewed. The radiological archives at the Armed Forces Institute of Pathology were searched for cases of surgically proven urachal carcinomas that had a computed tomographic (CT) scan as a part of their radiologic evaluation. CT images from all cases were evaluated to determine tumor morphology, presence and localization of calcification, extent of bladder invasion and metastases. Tumor size at presentation averaged 6cm. Twenty-one of 25 (84%) were mixed cystic solid lesions and 4/25 (16%) were completely solid. Calcifications were present in 18/25 (72%), with 11 peripherally located, 3 central only and 4 both. Bladder wall invasion was present in 23/25 (92%), but was seen as an intraluminal mass in only 13/25 (52%). The bulk of the mass was extravesicular in 22/25 (88%). Metastases were present in 12/25 (48%). Our series supports observations from other smaller series that a midline, calcified, supravesicular mass is highly suspicious, if not pathognomonic, for urachal carcinom
Immunoglobulin G4 Sclerosing Cholangitis: An Unusual Cause of Obstructive Jaundice-Case Report and Literature Review.
IgG4-related sclerosing cholangitis (IgG4-SC) is one of the most common extra-pancreatic manifestation of IgG4-related disease (IgG4-RD) and is clinically distinct from primary sclerosing cholangitis (PSC). IgG4-RD is an increasingly recognized immune-mediated fibroinflammatory systemic disease, mostly affecting middle-aged and older male populations that can affect multiple organs. The presence of extra-biliary clinical manifestations of IgG4-RD, such as parotid and lacrimal swelling, lymphadenopathy, autoimmune pancreatitis, and retroperitoneal fibrosis, if present could provide important clues to diagnosis. High serum IgG4 levels, characteristic radiological (e.g., sausage-shaped pancreas or periaortitis) or biopsy findings (high percentage of IgG4+ plasma cells, lymphoplasmacytic infiltrate, storiform fibrosis, or obliterative phlebitis) in the setting of these features is diagnostic of this disease process. However, isolated IgG4-SC might be a diagnostic challenge, and the distinction is important as management of this disorder is vastly different from other causes of cholangitis such as PSC. Systemic corticosteroid therapy is the mainstay of therapy
Nutritional Status of Food Insecure Older Adults
Approximately 9.8 million seniors across America were at risk of going hungry in 2015. The percentage of seniors who faced the threat of hunger was equivalent to the percentage of seniors compared with the whole population of the United States. The prevalence rate of hypertension, which contributes to heart attacks and strokes, is over 50%, and the prevalence rate of diabetes is over 25% in seniors. Both heart disease and diabetes are among the top 10 leading causes of death in America with heart disease being number one. Appropriate dieting is recommended as a way to prevent and treat both of these diseases. The goal of this study is to determine the effectiveness of support offered by food banks to provide adequate nutrition to food insecure older adults. A total of 300 seniors will be assessed prior to their first use of food bank support and three months after initiation using the Mini Nutritional Assessment. The data will be analyzed using descriptive statistics
Multi-systemic heart, kidney, and liver disease induced by gadolinium-based contrast treatment
Introduction: Gadolinium-based contrast agents have revolutionized clinical imaging. Conversely, there is growing concern of the overall safety of these agents. Once administered there is long-term retention of gadolinium in tissues. The long-term biologic impact of gadolinium retention is if monumental concern to patients and drug-regulating administrations. Methods: Our research team was the first to establish a rodent model of iatrogenic systemic fibrosis using chimeric mice. Wild-type C57/BL6 mice were randomized by sex and weight into contrast treatment (2.5 mmol/kg intraperitoneally, 20 doses over 4 weeks) or untreated groups. Ultrasound (Vevo 3100, FujiFilm VisualSonics) was performed several days-post final contrast treatment. Animals were perfused with formalin. Fixed tissues were prepared for magnetic resonance imaging (Bruker, 7.0T 40 cm bore MR scanner) or analyzed histologically and with electron microscopy (Hitachi HT7700, AMT 16-megapixel digital camera). Samples for the latter were further examined using scanning/transmission electron microscopy equipped with energy-dispersive x-ray spectroscopy (Jeol 2010F FASTEM with Oxford Analytical EDS). Results: Gadolinium-based contrast agents induced intracellular nanostructure formation in the kidney along with acute tubular and mitochondrial damage. Elemental analysis of these nanostructures by energy-dispersive X-ray spectroscopy revealed that these electron-dense structures were rich in gadolinium. Furthermore, exposure to gadolinium induced liver steatosis. Treatment groups paradoxically demonstrated increases in several functional cardiac parameters, particularly cardiac outputs. MRI analysis further illustrates gadolinium retention in the renal cortex of treatment groups. Conclusions: Exposure to gadolinium-based contrast agents leads to gadolinium retention in the form of electron-dense nanostructures. Gadolinium-based contrast agent treatment induces multi-systemic heart, kidney and liver disease
High Extraction Phosphors for Solid State Lighting
We have developed high-index, high efficiency bulk luminescent materials and novel nano-sized phosphors for improved solid-state white LED lamps. These advances can potentially contribute to reducing the loss in luminous efficiencies due to scattering, re-absorption, and thermal quenching. The bulk and nanostructured luminescent materials investigated are index matched to GaN and have broad and size-tunable absorption bands, size and impurity tuned emission bands, size-driven elimination of scattering effects, and a separation between absorption and emission bands. These innovations were accomplished through the use of novel synthesis techniques suitable for high volume production for LED lamp applications. The program produced a full-color set of high quantum yield phosphors with high chemical stability. In the bulk phosphor study, the ZnSeS:Cu,Ag phosphor was optimized to achieve >91% efficiency using erbium (Er) and other activators as sensitizers. Detailed analysis of temperature quenching effects on a large number of ZnSeS:Cu,Ag,X and strontium- and calcium-thiogallate phosphors lead to a breakthrough in the understanding of the âanti-quenchingâ behavior and a physical bandgap model was developed of this phenomena. In a follow up to this study, optimized phosphor blends for high efficiency and color performance were developed and demonstrated a 2-component phosphor system with good white chromaticity, color temperature, and high color rendering. By extending the protocols of quantum dot synthesis, âlargeâ nanocrystals, greater than 20 nm in diameter were synthesized and exhibited bulk-like behavior and blue light absorption. The optimization of ZnSe:Mn nanophosphors achieved ~85% QE The limitations of core-shell nanocrystal systems were addressed by investigating alternative deltadoped structures. To address the manufacturability of these systems, a one-pot manufacturing protocol was developed for ZnSe:Mn nanophosphors. To enhance the stability of these material systems, the encapsulation of ZnSeS particle phosphors and ZnSeS screens with Al{sub 2}O{sub 3} and TiO{sub 2} using ALD was shown to improve the stability by >8X and also increased the luminescence efficiency due to improved surface passivation and optical coupling. A large-volume fluidized bed ALD system was designed that can be adapted to a commercial ALD or vapor deposition system. Throughout the program, optical simulations were developed to evaluate and optimize various phosphor mixtures and device configurations. For example, to define the scattering properties of nanophosphors in an LED device or in a stand-off screen geometry. Also this work significantly promoted and assisted in the implementation of realistic phosphor material models into commercial modeling programs
Hyperbranched BisphosphonateâFunctional Polymers via SelfâCondensing Vinyl Polymerization and Postpolymerization Multicomponent Reactions
The synthesis of hyperbranched aminobisphosphonic acid polymers via reversible additionâfragmentation chain transfer (RAFT) selfâcondensing vinyl polymerization is reported. A novel acrylamideâfunctional chain transfer monomer is synthesized and characterized by 1H and 13C NMR spectroscopy, elemental analysis, and mass spectrometry. The monomer is subsequently copolymerized with an acrylamide monomer bearing a pendent amine group to create hyperbranched amineâfunctional polymers with degrees of branching dictated by changing the reaction stoichiometry. The aminobisphosphonate functional group is introduced via a 3âcomponent KabachnikâFields reaction. An alternate functionalization of the amine polymers to create acidâdegradable imine hydrogels is also employed. This work demonstrates the application of multicomponent reactions to RAFTâderived hyperbranched polymers and provides a new route to previously inaccessible polymers
Luminescence Properties of Thin Film Ta2 Zn3 O8 and Mn Doped Ta2 Zn3 O8
Blue luminescence from TaZZn30g and green luminescence from Mn doped TaZZn30g has been observed under low voltage cathodoluminescent excitation, In this article , the luminescence mechanisms of TaZZn30g and Mn doped TaZZn30 g are discussed in detail. The results suggest that the intrinsic blue luminescence of TaZZn30g results from a metal-to-ligand transition, whereas the green luminescence of Mn doped TaZZn30g results from the Mn 4T 1-6A I transition. The suppression of the blue intrinsic luminescence in Mn doped TaZZn30g suggests that efficient energy transfer from the host material to the Mn occurs. This energy transfer phenomenon is also discussed by comparing the photoluminescence excitation spectra of both thin film materials. Finally, the relative efficiency versus voltage and current density is demonstrated and discussed pertaining to field emission device operation
Facing Forward, Looking Back: Religion and Film Studies in the Last Decade
On November 17, 2012, at the American Academy of Religionâs National Meeting, the Religion, Film, and Visual Culture Group sponsored a session entitled, âFacing Forward, Looking Back: Religion and Film Studies in the Last Decade.â The session focused on four recent books in the field of Religion and Film: John Lydenâs Film as Religion: Myths, Morals and Rituals (NYU, 2003); S. Brent Plateâs Religion and Film: Cinema and the Re-Creation of the World (Wallflower Press, 2009); Antonio Sisonâs World Cinema, Theology, and the Human: Humanity in Deep Focus (Routledge, 2012); and Sheila Nayarâs The Sacred and the Cinema: Reconfiguring the âGenuinelyâ Religious Film (Continuum, 2012). Each author was present to make remarks on his or her book, and then three respondents made remarks on each of the books as well. The respondents were Stefanie Knauss, Rachel Wagner, and Jolyon Thomas. Joe Kickasola introduced the session, and moderated the discussion that followed. This session represented a rare opportunity for scholars of the field of Religion and Film to reflect on the past, present, and future directions of the field, and the Journal of Religion and Film is happy to be able to include the remarks of all the presenters here
Trichinella pseudospiralis in a wolverine (Gulo gulo) from the Canadian North
Species of Trichinella are a globally distributed assemblage of nematodes, often with distinct host ranges, which include people, domestic, and wild animals. Trichinella spp. are important in northern Canada, where dietary habits of people and methods of meat preparation (drying, smoking, fermenting as well as raw) increase the risk posed by these foodborne zoonotic parasites. Outbreaks in the arctic and subarctic regions of Canada and the United States are generally attributed to T. nativa (T2) or the T6 genotype, when genetic characterization is performed. We report the discovery of Trichinella pseudospiralis (T4), a non-encapsulated species, in a wolverine (Gulo gulo) from the Northwest Territories of Canada. This parasite has been previously reported elsewhere from both mammals and carnivorous birds, but our findings represent new host and geographic records for T. pseu- dospiralis. Multiplex PCR and sequencing of fragments of Cytochrome Oxidase Subunit I (COI) and D3 rDNA confirmed the identification. Phylogenetically, Canadian isolates linked with each other and others derived from Palearctic or Neotropical regions, but not elsewhere in the Nearctic (continental USA). We suggest that mi- gratory birds might have played a role in the dispersal of this pathogen 1000\u27s of km to northwestern Canada. Wolverines are not typically consumed by humans, and thus should not pose a direct food safety risk for tri- chinellosis. However, the current finding suggests that they may serve as an indicator of a broader distribution for T. pseudospiralis. Along with infection risk already recognized for T. nativa and Trichinella T6, our observa- tions emphasize the need for further studies using molecular diagnostics and alternative methods to clarify if this is a solitary case, or if T. pseudospiralis and other freeze susceptible species of Trichinella (such as T. spiralis) circulate more broadly in wildlife in Canada, and elsewhere
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