1,034 research outputs found

    Statistical (T) rates of convergence

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    The basis for comparing rates of convergence of two null sequences is that "x = (xn) converges (stat T) faster than z = (zn) provided that (xn/zn) is T-statistically convergent to zero" where T = (tmn) is a mean. In this paper we extend the previously known results either on the ordinary convergence or statistical rates of convergence of two null sequences. We also consider lacunary statistical rates of convergence

    Morphometric evaluation and surgical implications of the infraorbital groove, canal and foramen on cone-beam computed tomography and a review of literature

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    Background: The purpose of this study is to evaluate the anatomy, morphometry, and variations of infraorbital groove (IOG), infraorbital canal (IOC) and infraorbital foramen (IOF) on the cone-beam computed tomography (CBCT) images and to investigate their relations with surrounding structures.  Methods: IOG, IOC and IOF were evaluated retrospectively in CBCT images of 75 female (F) and 75 male (M) cases with a range of 18–65 years (F: 37.62 ± ± 13.55, M: 37.53 ± 15.87) by Planmeca Romexis programme. IOG, IOC and IOF were examined bilaterally (300 sides) in the cases. The 13 parameters were measured on these images in axial, sagittal and coronal planes.  Results: There was a very weak positive correlation between the age and the angle between IOC and IOG (p = 0.015, r = 0.198), there was a weak positive correlation between the age and skin thickness (p = 0.001, r = 0.281), and there was no correlation between the age and other parameters. A total of 21 (7%) IOCs were detected in maxillary sinus, bilaterally in 6 cases and unilaterally in 9 cases (5 on the left, 4 on the right). In 1 case, bilaterally, IOC was separated 2 canals while running anteriorly in the maxillary sinus. The larger one was directed to IOF in its normal course and the smaller one was directed to lateral wall of nasal cavity and opened to the inferior nasal meatus in front of the opening of nasolacrimal duct.  Conclusions: We suggest that the parameters found in the present study may facilitate prediction of the location of the infraorbital nerve. Knowledge of this exact position in relation to easily measurable parameters may decrease the risk of infraorbital nerve injury during surgical approaches directed to this region and might serve as a guide during local anaesthetic interventions for dentistry, ophthalmology, plastic surgery, rhinology, neurosurgery and dermatology.

    Anatomical evaluation of nasopalatine canal on cone beam computed tomography images

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    Background: Nasopalatine canal (NPC) (incisive canal) morphology is important for oral surgery techniques carried out on the maxilla, in the treatment of naso- palatine cyst, palatal pathologies that require a surgical intervention. Materials and methods: The morphology of NPC was classified in sagittal, coronal and axial planes on the cone beam computed tomography (CBCT). The length of NPC was found by measuring the distance between the mid-points of nasopalatine foramen and incisive foramen. The numbers, shapes and diameters of incisive and nasopalatine foramina were examined. Nasopalatine angle present between the NPC and the palate and anterior to the NPC was measured.  Results: In the sagittal plane, the shape of NPC was classified in six groups: 26.7% hourglass, 14.7% cone, 13.3% funnel, 16.0% banana, 28.7% cylindrical and 0.7% reverse-cone-shaped. In the coronal plane, shape of NPC was classified in three groups: 63.3% Y-shaped, 36.0% single canal, 0.7% double canal and external border of NPC was classified in four groups: 26.7% U, 28.7% Y, 44.0% V and 0.7% reverse-V-shaped. In the axial plane, the shape of nasopalatine foramen, incisive foramen and NPC at the mid-level was evaluated. The shape of the canal was detected as four types at three evaluated levels: round, oval, heart- and triangle-shaped. It was seen in every three axial planes that the round group is more than the others.  Conclusions: The morphological properties and variations of NPC should be con- sidered with a correct radiological evaluation so as to prevent the complications and improper practices in local anaesthesia, maxillary surgery and implant surgery practices. Especially dentists, otolaryngologist and plastic surgeons need to know the anatomy and variations of NPC.

    Faculty of responsibility: a key concept to cope with the ethical challenges medical students face

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    During their educational life, medical students encounter several challenges, the origins and causes of which vary. This paper explores and attempts to scrutinize two of these challenges, before eventually introducing the concept of responsibility. First, this paper describes the general characteristics of medical schools, medical students, and medical education. Second, two different ethical challenges that medical students confront are then delineated: the anxiety of continuously questioning ‘while being trained, do I cause patients to receive suboptimal health care?’ and occasionally feeling obligated, consequently, to breach the ethical boundaries to practice procedures on patients. Finally, the faculty of responsibility and its components are introduced and discussed as a model that can overcome these ethical challenges

    Radii of k-starlikeness of order α of Struve and Lommel functions

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    WOS:000661139500001In the present work our main objective is to determine the radii of k– starlikeness of order a of the some normalized Struve and Lommel functions of the first kind. Furthermore it has been shown that the obtained radii satisfy some functional equations. The main key tool of our proofs are the Mittag-Leffler expansions of the Struve and Lommel functions of the first kind and minimum principle for harmonic functions. Also we take advantage of some basic inequalities in the complex analysis

    3d transition metal doping of semiconducting boron carbides

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    The introduction metallocenes, in particular ferrocene (Fe(η5-C5H5)2), cobaltocene (Co(η5-C5H5)2), and nickelocene (Ni(η5-C5H5)2), together with the carborane source molecule closo-1,2-dicarbadodecaborane, during plasma enhanced chemical vapor deposition, will result in the transition metal doping of semiconducting boron carbides. Here we report using ferrocene to introduce Fe dop¬ants, and a semiconducting boron-carbide homojunction has been fabricated. The diode characteristics are very similar to those fabricated with Co and Ni doping

    trans-rac-[1-Oxo-2-phenethyl-3-(2-thien­yl)-1,2,3,4-tetra­hydro­isoquinolin-4-yl]methyl 4-methyl­benzene­sulfonate

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    The title compound, C29H27NO4S2, was synthesized by reaction of trans-rac-4-(hydroxy­meth­yl)-2-phenethyl-3-(thio­phen-2-yl)-3,4-dihydro­isoquinolin-1(2H)-one and 4-methyl­benzene-1-sulfonyl chloride in the presence of Et3N in CH2Cl2. The relative orientations of the benzene ring (A) of the 3,4-dihydro­isoquinolinone ring system, the thio­phene ring (B), the benzene ring (C) of the methyl­benzene group and the phenyl ring (D) result in the following dihedral angles: A/B = 80.91 (16), A/C = 22.79 (18), A/D = 9.9 (2), B/C = 80.73 (19), B/D = 88.9 (2) and C/D = 29.9 (2)°. The crystal structure is stabilized by weak inter­molecular C—H⋯O hydrogen bonds and C—H⋯π inter­actions

    Methyl trans-rac-2-hexyl-1-oxo-3-(2-pyrid­yl)-1,2,3,4-tetra­hydroisoquinoline-4-carboxyl­ate

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    The title compound, C22H26N2O3, was synthesized by esterification of trans-rac-2-hexyl-1-oxo-3-(2-pyrid­yl)-1,2,3,4-tetra­hydro­isoquinoline-4-carboxylic acid in the presence of H2SO4 in methanol. The dihedral angle between the benzene and pyridine rings is 84.46 (17)°. The piperidine ring adopts a screw-boat conformation. In the crystal, inversion dimers linked by two C—H⋯O bonds occur

    Methyl trans-(±)-1-oxo-2-phenethyl-3-(thio­phen-2-yl)-1,2,3,4-tetra­hydro­isoquinoline-4-carboxyl­ate

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    In the title compound, C23H21NO3S, the piperidine ring of the tetra­hydro­isoquinolinone unit adopts a screw-boat conformation. The thio­phene ring is disordered in a 0.700 (3):0.300 (3) ratio by an approximate 180° rotation of the ring around the C—C bond linking the ring to the tetra­hydro­isoquinolinone unit. The benzene ring of the tetra­hydro­isoquinolinone unit makes dihedral angles of 83.1 (2) and 62.38 (11)° with the major occupancy thio­phene ring and the phenyl ring, respectively. The dihedral angle between the phenyl ring and the thio­phene ring is 71.0 (2)°. In the crystal structure, mol­ecules are linked together by inter­molecular C—H⋯O and C—H⋯π inter­actions

    Norditerpenoids with selective anti-cholinesterase activity from the roots of Perovskia atriplicifolia Benth

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    Inhibition of cholinesterases remains one of a few available treatment strategies for neurodegenerative dementias such as Alzheimer's disease and related conditions. The current study was inspired by previous data on anticholinesterase properties of diterpenoids from Perovskia atriplicifolia and other Lamiaceae species. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition by the three new natural compounds-(1R,15R)-1-acetoxycryptotanshinone (1), (1R)-1-acetoxytanshinone IIA (2), and (15R)-1-oxoaegyptinone A (3)-as well as, new for this genus, isograndifoliol (4) were assessed. Three of these compounds exhibited profound inhibition of butyrylcholinesterase (BChE) and much weaker inhibition of acetylcholinesterase (AChE). All compounds (1-4) selectively inhibited BChE (IC(50) = 2.4, 7.9, 50.8, and 0.9 µM, respectively), whereas only compounds 3 and 4 moderately inhibited AChE (IC(50) 329.8 µM and 342.9 µM). Molecular docking and in silico toxicology prediction studies were also performed on the active compounds. Natural oxygenated norditerpenoids from the traditional Central Asian medicinal plant P. atriplicifolia are selective BChE inhibitors. Their high potential makes them useful candidate molecules for further investigation as lead compounds in the development of a natural drug against dementia caused by neurodegenerative diseases
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