708 research outputs found

    Influence of base and photoacid generator on deprotection blur in extreme ultraviolet photoresists and some thoughts on shot noise

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    A contact-hole deprotection blur metric has been used to monitor the deprotection blur of an experimental open platform resist (EH27) as the wt % of base and photoacid generator (PAG) were varied. A six times increase in base wt % is shown to reduce the size of successfully patterned 1:1 line-space features from 52 to 39 nm without changing deprotection blur. Corresponding isolated line edge roughness is reduced from 6.9 to 4.1 nm. A two times increase in PAG wt % is shown to improve 1:1 line-space patterning from 47 to 40 nm without changing deprotection blur or isolated line edge roughness. A discussion of improved patterning performance as related to shot noise and deprotection blur concludes with a speculation that the spatial distribution of PAG molecules has been playing some role, perhaps a dominant one, in determining the uniformity of photogenerated acids in the resists that have been studied. © 2008 American Vacuum Society

    Multiple Endodontic Guides for Root Canal Localization and Preparation in Furcation Perforations: A Report of Two Cases

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    Perforations are managed by surgical or nonsurgical approach depending on the relationship of the perforation site to the crestal bone level and attachment apparatus. Relocating the canal orifice or root canal close to the perforation site is quite challenging even with the aid of a dental operating microscope. In these two case reports, guided endodontics was applied in root canal localization and preparation in cases of furcation perforations. This is the report of two patients (42 and 15-year-old, respectively) who were referred for root canal treatment of the mandibular right first molar. The first case complained of pain on biting, foul odor, and bad taste. The referring dentist noted a furcation perforation and an inability to locate the mesial canals. Radiographic examination showed furcation radiolucency. Definitive diagnosis was symptomatic apical periodontitis. The second case complained of severe throbbing pain along with pain on biting. Mesial canals could not be detected due to a furcation perforation as noted by the referring dentist. Radiographic examination revealed a large furcation perforation and related bone resorption. Definitive diagnosis was acute apical abscess. In each case, a silicone impression of the mandibular arch was obtained and scanned along with cone-beam computed tomography scan to plan for localization and preparation of the mesiobuccal canals using implant planning software. Multiple guides were fabricated through rapid prototyping and allowed for the correct orientation and insertion of endodontic files through the canal. Canals were prepared and then obturated using warm vertical compaction technique and the perforation were repaired by mineral trioxide aggregate (MTA). Six-month and one-year follow-ups revealed no symptoms and evidence of radiographic healing. Thus, multiple endodontic three-dimensional guides can be successful in root canal localization and preparation in cases of furcation perforations

    Selective versus stepwise removal of deep carious lesions in permanent teeth: a randomised controlled trial from Egypt-an interim analysis

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    OBJECTIVES: To compare the success, survival and costs of selective versus stepwise carious tissue removal (SE/SW) in permanent teeth with deep (>2/3 dentine depth) carious lesions. DESIGN: Randomised controlled, unicentre, clustered two-arm superiority trial. SETTING: Outpatient clinic of a private university in Cairo, Egypt. PARTICIPANTS: One hundred and fifteen participants (n=132 teeth), aged 18-47 years, from Cairo, Egypt, were enrolled. Premolars/molars with occlusal/occlusal-proximal deep lesions (radiographically >2/3 dentine), sensible pulps, without spontaneous pain, were included. INTERVENTIONS: Peripheral carious tissue removal to hard dentine was performed. Pulpo-proximally, soft dentine was left. A glass ionomer (GI) restoration was placed. After 3-4 months, teeth were randomly allocated to SE (n=66), with reduction of the GI into a base and no further tissue removal, followed by a composite resin restoration, or SW (n=66), with full removal of the GI, additional excavation until firm dentine pulpo-proximally, followed by a GI-based composite restoration. Mean follow-up was 1 year. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome was success (absence of endodontic/restorative complications). Secondary outcomes were tooth survival and initial and total treatment costs. RESULTS: Zero/five pulp exposures occurred during SE/SW, and seven/five SE/SW teeth required endodontic therapy. Success after 12 months was 89.4% for SE and 84.9% for SW. The estimated mean time free of complications was 23 and 18 months for SE and SW, respectively, without significant differences between SE and SW (p>0.05/Cox). Initial treatment costs were significantly higher for SW (mean (SD): 507.5 (123.4) Egyptian pounds (EGP)) than SE (mean (SD): 456.6 (98.3) EGP), while total costs showed no significant difference (p>0.05). CONCLUSION: Within the limitations of this interim analysis, and considering the depth of these lesions (>2/3 dentine), SE and SW showed similar risk of failure and overall costs after 1 year

    Proportional Hazard Bivariate Kumaraswamy Model Applied on Fish Mercury Concentration

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    International advisory bodies have developed guidelines for testing mercury and aquatic items to protect human health and international trade. The mercury absorption in fish has a great effect on human health. For modeling this problem, a new bivariate distribution using the proportional hazard rate (PHR) model with Kumaraswamy marginal called BKPH is derived and studied via statistical properties and reliability measures. Moreover, several methods of parameter estimation are discussed, including maximum likelihood estimation (MLE), method of moments estimation (MME), and inference function for margins estimation (IFM). In the simulation study, the performance of estimators depending on their estimation methodologies is compared. Finally, a comparative study of the proposed BKPH with several bivariate Kumaraswamy distributions via goodness of fit criteria was introduced. The results of the study proved the potentiality of the BKPH model and has a best fitting on mercury fish absorption data

    Analysis of Chemical and Microbial Change During Storage of Overripe Tempeh Powder as Seasoning Material

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    Tempeh and other soy-derived products are historically and currently some of the most important foods in the Asian region where diets remain predominantly plant-based. Overripe tempeh (tempe semangit) is a term used for over-fermented tempeh with pungent odor and darkening appearance commonly used in Javanese cuisine. Unique taste and odor of overripe tempeh lead to the exploration of its potencies as condiment, which may add the nutritional, safety and economic values of tempeh. In this research, overripe tempeh is made into powder for better appearance and availability. Oven drying at 60oC and freeze drying were applied to the overripe tempeh until it reached moisture content below 5%, followed by subsequent crushing into powder using electric grinding machine. As seasoning material, the tempeh powder and overripe tempeh powder were then analyzed for their stability. Observations in chemical and microbial changes during storage were also applied to selected product during storage. Parameters observed during the research are: moisture content, protein content, acid content, total microbial count and total coliform. Oven dried overripe tempeh (S60) has higher moisture content but lower in acid content, total microbial count and total coliform compared to freeze dried overripe tempeh (SFD)

    Experimental Shear Behavior of Fiber Reinforced Composite Corrugated Plate Girders at Intermediate Supports

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    Bridges with corrugated steel webs have been extensivelyconstructed in different countries. A trapezoidally corrugatedsteel plate is composed of a series of longitudinal andinclined subpanels. For a steel corrugated web girder, it isassumed that the web carries merely shear forces due to theaccordion effect [1,2]. The web in such a girder was found tocarry insignificant longitudinal stresses from the primaryflexure. Consequently, the bending moment is nearly carriedby its flanges. Thus, it is worth pointing out that the shearstrength can be determined without consideration ofmoment-shear interaction. But it was found that problem inan area where intermediate supports that shear forces arecompletely carried by web, and found that the value of theshear resistance, which is a concrete slab by almost beneglected. In recent years has been the study of differenttypes of materials to increase the efficiency of concrete andincrease the shear forces at the intermediate supports. Thusin this research, the effect of adding fiber to the concrete incomposite corrugated plate girders at intermediate supportswas investigated

    The Interactions of Surface Damage on RF Cavity Operation

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    Studies of low frequency RF systems for muon cooling has led to a variety of new techniques for looking at dark currents, a new model of breakdown, and, ultimately, a model of RF cavity operation based on surface damage. We find that cavity behavior is strongly influenced by the spectrum of enhancement factors on field emission sites.Three different spectra are involved: one defining the initial state of the cavity, the second determined by the breakdown events, and the third defining the equilibrium produced as a cavity operates at its maximum field. We have been able to measure these functions and use them to derive a wide variety of cavity parameters: conditioning behavior, material, pulse length, temperature, vacuum, magnetic field, pressure, gas dependence. In addition we can calculate the dependence of breakdown rate on surface field and pulse length. This work correlates with data from Atom Probe Tomography. We will describe this model and new experimental data

    Impact of Tactile Stimulation on Neurobehavioral Development of Premature Infants in Assiut City

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    Objective: To assess impact of tactile stimulation on neurobehavioral development of premature infants in Assiut City. Design: Quasi-experimental research design. Setting: The study was conducted in the Neonatal Intensive Care Unit at Assiut University Children Hospital, Assiut General Hospital, Health Insurance Hospital (El-Mabarah Hospital) and El-Eyman for Gynecology and Obstetric Hospital. Subjects: The study subjects included a convenient sample of 50 premature infants divided into study or control groups and they were matched with gestational age and birth weight. Tool: Brazelton Neonatal Behavioral Assessment Scale is used to assess neurobehavioral development of infants from birth to two months of age. Method: Premature infants divided into two groups; (a) study group who receiving tactile stimulation (b) control group who receiving routine hospital care only. Neurobehavioral development using Brazelton’s Neonatal Behavior Assessment Scale (NBAS) was assessed at initial contact and after 5 days of intervention and on discharge. Results: showed that the premature infants of the study had better neurobehavioral development than those in the control group with statistical significant differences were found between the study and the control groups Conclusion: It was concluded from the findings of the current study that premature infants who received tactile stimulation had better neurobehavioral development than those who didn’t receive it and had only the hospital routine care. Keywords: Tactile stimulation, neurobehavioral development, premature infant

    Acetyl-L-carnitine and/or liposomal co-enzyme Q10 prevent propionic acid-induced neurotoxicity by modulating oxidative tissue injury, inflammation, and ALDH1A1-RA-RARα signaling in rats

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    Propionic acid (PPA) is a short-chain fatty acid produced endogenously by gut microbiota and found in foodstuffs and pharmaceutical products as an additive. Exposure to PPA has been associated with the development of autism spectrum disorder (ASD). The purpose of this study was to investigate the protective effect of acetyl‐L‐carnitine (ALCAR) and liposomal Co-enzyme Q10 (CoQ10) against cerebral and cerebellar oxidative injury, inflammation, and cell death, and alterations in ALDH1A1-RA-RARα signaling in an autism-like rat model induced by PPA. The rats were treated with PPA and concurrently received ALCAR and/or CoQ10 for 5 days. The animals were sacrificed, and the cerebral cortex and cerebellum were collected for analysis. PPA caused histopathological alterations along with increased malondialdehyde (MDA), NF-κB p65, TNF-α, and IL-6 in the cerebrum and cerebellum of rats. Reduced glutathione (GSH) and antioxidant enzymes were declined in the brain of rats that received PPA. Concurrent treatment with ALCAR and/or CoQ10 prevented tissue injury, decreased MDA, NF-κB p65, and pro-inflammatory cytokines, and enhanced cellular antioxidants in PPA-administered rats. ALCAR and/or CoQ10 upregulated Bcl-2 and decreased Bax and caspase-3 in the brain of rats. In addition, ALCAR and/or CoQ10 upregulated cerebral and cerebellar ALDH1A1 and RARα in PPA-treated rats. The combination of ALCAR and CoQ10 showed more potent effects when compared with the individual treatments. In conclusion, ALCAR and/or CoQ10 prevented tissue injury, ameliorated oxidative stress, inflammatory response, and apoptosis, and upregulated ALDH1A1-RA-RARα signaling in the brain of autistic rats
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