1,067 research outputs found

    Essential cohomology for elementary abelian p-groups

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    For an odd prime p the cohomology ring of an elementary abelian p-group is polynomial tensor exterior. We show that the ideal of essential classes is the Steenrod closure of the class generating the top exterior power. As a module over the polynomial algebra, the essential ideal is free on the set of Mui invariants.Comment: 10 page

    The arterial anatomy of the saphenous flap: a cadaveric study

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    The saphenous flap is a fasciocutaneous flap generally used for knee and upper third of the leg coverage. Due to various descriptions of the saphenous flap, such as venous, sensory, and free flap, the origin and distributing characteristics of the saphenous artery are important for plastic surgeons. The aim of this cadaveric study was to evaluate the anatomical features of the saphenous flap. The pedicles of the saphenous flap were dissected under 4 x loop magnification in thirty-two legs of 16 formalin-fixed adult cadavers. The findings of this anatomic study were as follows: Descending genicular artery originated from the femoral artery in all of the cases. The first musculoarticular branch, which arose from descending genicular, to the vastus medialis muscle existed in all dissections. The second branch was the saphenous artery which seperately originated from the descending genicular artery in all of the cases. At the level of origin the mean diameter of the saphenous artery was found to be 1.61 mm. The muscular branches to the anterior or posterior sides of the sartorious muscle existed in all of the dissections. Two vena comitantes and a saphenous nerve were accompanying the saphenous artery in all cadavers. The mean distance between the origin of the artery and interepicondylar line of tibia was 115 mm. The muscular branches of the saphenous artery to the gracilis muscle were encountered 6.66% of the cases. The cutaneous branches numbered between one and four, and arose 3.5 to 9.5 cm from the site of origin of the saphenous artery. The distal end of the saphenous artery reached approximately 122 mm distally to the knee joint in all cases. Due to variations of the arterial anatomy and limited number of anatomic studies of the saphenous flap, we studied the topography and anatomy of the saphenous artery for increasing reliability of the saphenous flap

    Anatomy of the anteromedial thigh flap based on the oblique branch of the descending branch of the lateral circumflex femoral artery

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    Anteromedial thigh (AMT) flaps based on lateral circumflex femoral artery (LCFA) have characteristics which make them favourable for use in reconstruction of extensive thigh, head, neck and leg defects. AMT flap which is elevated on the artery has the advantages of low donor site morbidity and preservation of main arteries. Due to inconstant anatomy of the pedicle, the flap is mostly not preferable. Hence, we aimed to describe the anatomical features of the unnamed branch of the descending branch of the LCFA harvesting AMT flap. For this purpose, the external iliac artery was displayed bilaterally on 15 adult (13 males and 2 females; age range 55–82 years) preserved cadavers using latex injection. The perforator branch of the descending branch from the LCFA was microdissected under 4× loupe magnification. The perforator branch was located 28.53 (20.20–34.20) cm distal to the anterior superior iliac spine, 22.12 (13.40–28.00) cm distal to the pubic tubercle, and 13.20 (10.80–16.20) cm proximal to the interepicondylar line. At the level of origin point the mean diameter of the perforating branch was 0.17 cm and the mean diameter of its cutaneous branch was 0.14 cm. The mean length of the pedicle was 5.71 (3.70–9.00) cm. We conclude that our findings contribute to the literature in terms of anatomical knowledge for surgical safety.

    Suprascapular foramen: a rare variation caused by ossified suprascapular ligaments

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    Background: The aim of this study was to investigate the incidence of the suprascapular foramen in West Anatolian population. Materials and methods: Eighty-one dried human scapulae of West Anatolian people of unknown ages and gender belonging to the Anatomy Department Laboratory of Dokuz Eylul University Medical School were examined macroscopically. The vertical and transverse diameters of the suprascapular foramen and central thickness of the ossified ligaments were measured with calliper in millimetres and digital calliper, respectively. Results: We observed the suprascapular foramen due to ossification of the suprascapular ligament only in 2 of 81 (2.47%) scapulae. The vertical and transverse diameters of the suprascapular foramen and central thickness of the ossified ligaments (No. 1 and No. 2) were measured as 8.0 mm vs. 4.0 mm, 3.6 mm vs. 2.0 mm and 4.0 mm vs. 1.4 mm, respectively. Conclusions: The suprascapular foramen caused by ossified suprascapular ligament is rarely observed variation in West Anatolian population.

    Assessment of the orbit morphometry on West Anatolian dry skulls

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    The orbit is very frequently damaged by traumas which result in not only bone deficits, but also functional deformities if reconstruction is not appropriate. Anatomical exposure of the bony orbit is of importance for both anatomists and surgeons who perform operation on this area. The current study evaluated the group of morphometrical parameters on 74 adult West Anatolian dry skulls and stereological surface area on the dry skull orbits while describing the clinical importance. Surface areas on the orbital base of the skulls were also evaluated using stereological method, bilaterally. Anthropological assessment of orbital base (in terms of width and height) revealed no significant difference between right and left sides. Both width and height of the optic foramen were significantly higher on the right side compared to left. The distances between the margins (medial, lateral, superior, inferior) of the orbital base and the optic foramen were longer on the right side compared to left, except the distances between the lateral margins. There was no significant difference among the subjects between right and left sides with respect to the orbital base in terms of stereological area calculation. The results are significant because there are no recorded anatomical data on West Anatolian skulls at previous researches. (Folia Morphol 2018; 77, 1: 105–109

    Enhanced catalytic performance of MnxOy-Na2WO4/SiO2 for the oxidative coupling of methane using an ordered mesoporous silica support

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    The oxidative coupling of methane is a highly promising reaction for its direct conversion. Silica supported MnxOy–Na2WO4 is a suitable catalyst for this reaction. In this study, a variety of different SiO2 materials have been tested as supports. Surprisingly, the application of ordered mesoporous silicas, here exemplarily shown for SBA-15 as support materials, greatly enhances the catalytic performance. The CH4 conversion increased two fold and also the C2 selectivity is strongly increased

    Silica material variation for the Mn<sub>x</sub>O<sub>y</sub>-Na<sub>2</sub>WO<sub>4</sub>/SiO<sub>2</sub>

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    The oxidative coupling of methane (OCM) is one of the best methods for the direct conversion of methane.Among the known OCM catalysts, MnxOy-Na2WO4/SiO2 is a promising candidate for an industrial appli-cation, showing a high methane conversion and C2 selectivity, with a good stability during long-termcatalytic activity tests. In the present study, some results have been already published and discussedbriefly in our previous short communication. However, we herein investigated comprehensively theinfluence of various silica support materials on the performance of the MnxOy-Na2WO4/SiO2 systemin the OCM by means of ex situ and in situ XRD, BET, SEM and TEM characterization methods andshowed new results to reveal possible support effects on the catalyst. The catalytic performance of most MnxOy-Na2WO4/SiO2 catalysts supported by different silica support materials did not differ substan-tially. However, the performance of the SBA-15 supported catalyst was outstanding and the methaneconversion was nearly twofold higher in comparison to the other silica supported catalysts at similar C2 selectivity as shown before in the communication. The reason of this substantial increase in performancecould be the ordered mesoporous structure of the SBA-15 support material, homogeneous dispersion ofactive components and high number of active sites responsible for the OCM
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