540 research outputs found

    Preparation and Characterization of Ti(2)O(3) Films Deposited on Sapphire Substrate by Activated Reactive Evaporation Method

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    (001)-oriented Ti(2)O(3) films were epitaxially grown on a(001)-face of sapphire single-crystalline substrate by an activated reactive evaporation method. The formation ranges of stoichiometric and nonstoichiometric Ti(2)O(3) films were determined as a function of the substrate temperature (Ts), the oxygen pressure (Po(2)) and the deposition rate. Stoichiometric Ti(2)O(3) films were grown at Ts≧673K under Po(2)≧1.0×10(-4)Torr, which showed the metal-insulator transition with a sharp change in electrical resistivity from 3.5×10(-2) to 2.6×10(-3)Ωcm at 361K. Nonstoichiometric films prepared under less oxidized conditions did not exhibit the transition. The nonstoichiometry of the Ti(2)O(3)films was discussed in terms of excess Ti ions

    Renormalization of potentials and generalized centers

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    We generalize the Riesz potential of a compact domain in Rm\mathbb{R}^{m} by introducing a renormalization of the rαmr^{\alpha-m}-potential for α0\alpha\le0. This can be considered as generalization of the dual mixed volumes of convex bodies as introduced by Lutwak. We then study the points where the extreme values of the (renormalized) potentials are attained. These points can be considered as a generalization of the center of mass. We also show that only balls give extreme values among bodied with the same volume.Comment: Adv. Appl. Math. 48 (2012), 365--392 Figure 11 has been corrected after publication. Theorem 3.12 and the exposition of Lemma 2.15 are modified in version

    Automated synthesis, preclinical toxicity, and radiation dosimetry of [F-18]MC225 for clinical use:a tracer for measuring P-glycoprotein function at the blood-brain barrier

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    Introduction: [18F]MC225 is a selective substrate for P-glycoprotein (P-gp) that has good metabolic stability and shows higher baseline uptake compared with other P-gp substrates such as (R)-[11C]Verapamil. Prior to clinical translation, it is necessary to perform process validation of the radiosynthesis, assessment of preclinical toxicity, and radiation dosimetry. Methods: The production of [18F]MC225 was automated on a CFN-MPS200 multipurpose synthesizer. The acute toxicity of MC225 was evaluated at a dose of 2.5 mg/kg bodyweight, which is more than 10,000-fold the postulated maximum clinical dose of [18F]MC225. The acute toxicity of [18F]MC225 injection at a 200-fold dose, to administer a postulated dose of 185 MBq of [18F]MC225, was also evaluated after the decay-out of 18F. The mutagenicity of MC225 was studied by a reverse mutation test using Salmonella typhimurium and Escherichia coli (Ames test). In vivo biodistribution and dosimetry studies of [18F]MC225 were carried out in normal mice. Human dosimetry was estimated using OLINDA software. Results: The mean decay-corrected yields of [18F]MC225 at end of synthesis were 13%, with > 99% radiochemical purity, > 1000 GBq/!mol molar activity, and ! 1.5 !g/185 MBq of total chemical contents. All process validation batches complied with the product specifications and the process was confirmed to be appropriate for the production of [18F]MC225. No acute toxicity of MC225 or [18F]MC225 injection was found. No mutagenic activity was observed for MC225. The biodistribution study demonstrated both hepatobiliary and renal excretion of radioactivity. The most critical organ was the pancreas, with (63.8 !Gy/MBq) or without urination (63.9 !Gy/MBq) at 360 min after injection. The estimated effective dose (!Sv/MBq) with and without urination at 360 min after injection was calculated as 15.7 and 16.9, respectively. Conclusion: [18F]MC225 shows acceptable pharmacological safety at the dose required for adequate PET imaging. The potential risk associated with [18F]MC225 PET imaging is well within acceptable dose limits

    Cystic Artery Variations and Associated Vascular Complications in Laparoscopic Cholecystectomy

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    Substantial knowledge of the arterial supply and its anatomical variations of the gall bladder and liver are important in all the hepatobiliary surgical procedures. The arterial supply of gallbladder called cystic artery (CA) is a vital structure required to get ligated or clipped in the path of laparoscopic cholecystectomy. The possible concerns like intra-operative bleeding or adjoining accidental injuries will almost always be focused on the research consisting of dissection and clipping with cystic artery. Pseudoaneurysm of the cystic artery has additionally been belonging to the presence of acute cholecystitis or pancreatitis. An original supply of CA is usually assessed depending on the existence of hepatic artery variants. Laparoscopic cholecystectomy is really a recent and arduous noninvasive procedure and might even result in substantial unintended effects possibly iatrogenic or in the form of post-procedural complications. The perfect knowledge of anatomy in addition to feasible variation of cystic artery is mandatory. An efficient operative strategy and consciousness are probably the key components with all the results and marginal likelihood of complications, which often can be ultimately attainable. Within this chapter, we have attempted to explore some variations of cystic artery, complications and management

    An autoencoder-classified cluster of SARS-CoV-2 strain with two mutations in helicase

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    Using an autoencoder-based analysis to classify genomes of SARS-CoV-2 coronaviruses, we found a cluster consisting only of a specific genotype with two mutations in the helicase. This virus genotype, called C-type SARS-CoV-2, was almost exclusively prevalent in the United States from March to July 2020. This type of virus, characterized by a pair of the C17747T (P504L) and A17858G (Y541C) mutations on the nsp13 gene, had never been highly prevalent at any other time or in any other part of the world. In the U.S., Washington State was the center of the epidemic, and the C-type viruses, along with the viruses with wild-type helicase, seemed to have aroused the pandemic. In Washington State, USA, the CoViD-19 epidemic during the first two months of the year, starting at the end of February 2020, was mainly caused by the type-C virus. During this period, the infection spread rapidly; from May onwards, the number of viruses with wild-type helicases became higher than that of type-C viruses, and no type-C viruses have been collected since early July. The involvement of the helicase in this COVID-19 disease was discussed

    Perihilar or (Hilar) Cholangiocarcinoma: Interventional to Surgical Management

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    Peri-hilar cholangiocarcinoma (PHC) or hilar cholangiocarcinoma (HCCA) characterizes a critical effort to assess significantly sick patients. The existing scenery and proof to the diagnosis and treatments for hilar cholangiocarcinoma are improving day by day. Patients with HCCA encounter numerous obstacles in acquiring efficient therapies. The condition is uncommon, and the majority patients don’t have any distinct risk factors, doing selection process inadequate. The initial signs and symptoms in many cases are non-specific, and in many patients the tumors are not resectable because of involvement of the perihilar structures. MRI with MRCP offers further information about the extent of biliary involvement. Furthermore, endoscopic stenting and percutaneous drain could be useful for intricate hilar strictures. Surgical resections with negative margins are related to good likelihood of survival for patients representing with HCCA. Regardless of the accessibility of curative treatment strategies such as operative resection and liver transplantation, most sufferers with HCCA shows with repeated, metastases or locally advanced disease with a poor prognosis. Within this chapter, we have tried to elaborate the modalities of treatment from intervention to surgical approach for HCCA

    In Vivo Evaluation of α7 Nicotinic Acetylcholine Receptor Agonists [11C]A-582941 and [11C]A-844606 in Mice and Conscious Monkeys

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    BACKGROUND: The alpha7 nicotinic acetylcholine receptors (nAChRs) play an important role in the pathophysiology of neuropsychiatric diseases such as schizophrenia and Alzheimer's disease. The goal of this study was to evaluate the two carbon-11-labeled alpha7 nAChR agonists [(11)C]A-582941 and [(11)C]A-844606 for their potential as novel positron emission tomography (PET) tracers. METHODOLOGY/PRINCIPAL FINDINGS: The two tracers were synthesized by methylation of the corresponding desmethyl precursors using [(11)C]methyl triflate. Effects of receptor blockade in mice were determined by coinjection of either tracer along with a carrier or an excess amount of a selective alpha7 nAChR agonist (SSR180711). Metabolic stability was investigated using radio-HPLC. Dynamic PET scans were performed in conscious monkeys with/without SSR180711-treatment. [(11)C]A-582941 and [(11)C]A-844606 showed high uptake in the mouse brain. Most radioactive compounds in the brain were detected as an unchanged form. However, regional selectivity and selective receptor blockade were not clearly observed for either compound in the mouse brain. On the other hand, the total distribution volume of [(11)C]A-582941 and [(11)C]A-844606 was high in the hippocampus and thalamus but low in the cerebellum in the conscious monkey brain, and reduced by pretreatment with SSR180711. CONCLUSIONS/SIGNIFICANCE: A nonhuman primate study suggests that [(11)C]A-582941 and [(11)C]A-844606 would be potential PET ligands for imaging alpha7 nAChRs in the human brain
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