163 research outputs found
Experimental Investigation of the Influence of the Foreploughshare and the Disk Coulter on the Tillage Quality and the Tractor Fuel Consumption
Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 4 (2002): A. Natsis, G. Papadakis, and I. Pitsilis. Experimental Investigation of the Influence of the Foreploughshare and the Disk Coulter on the Tillage Quality and the Tractor Fuel Consumption. Vol. IV. December 2002
Cost effectiveness of bio-ethanol to reduce carbon dioxide emissions in Greece
The purpose of this study is to evaluate ethanol cost- effectiveness with regards to carbon dioxide emissions. Actually, bio-fuel production is only viable thanks to the tax credit policy resulting in economic âdeadweightâ loss. The environmental performance is assessed under the Life Cycle Assessment (LCA) framework. Economic burden to society to support the activity divided by avoided CO2 equivalent emissions indicates the bio-ethanol cost effectiveness. Agricultural feedstock supply that comprises of sugarbeets, grains and industrial processing sub-models are articulated in a regional sector model. The maximization of total welfare determines optimal crop mix for farmers and the best configurations for industry. This is illustrated for bio-ethanol produced by the ex-sugar industry in Thessaly, Greece. Life cycle activity analysis showed that, at the optimum, CO2 emission is reduced between 1 and 1.5 t of carbon dioxide equivalent per ton of ethanol. The unitary cost falls in the range of 100 to 250 euro per ton of CO2 and it is remarkably dependent on the agricultural policy scenario.Cost effectiveness, ethanol, mathematical programming, life cycle assessment, greenhouse gases
Co-existence of os acromiale with suprascapular osseous bridge: a case report and review of the literature
We report on a very rare case of co-existence of os acromiale with suprascapular
osseous bridge in a dry scapula. The frequency of os acromiale alone ranges
from 1.3 to 15%, while the frequency of suprascapular osseous bridge varies
between 0.036% and 12.5%. We review the relative literature and emphasize
the fact that such knowledge is important for a physician in order to avoid
misdiagnosis of an acromion fracture and lytic lesion of the scapula
Retro-oesophageal right subclavian artery in association with thyroid ima artery: a case report, clinical impact and review of the literature
A 37-year-old female Caucasian cadaver with an aberrant right subclavian artery extending from the left side of the aortic arch and following a retro-oesophageal course is presented. A non-recurrent right laryngeal nerve and a thyroid ima artery arising from the lower part of the middle third of the right common carotid artery coexisted. The brachiocephalic trunk was absent, while both common carotid arteries and left subclavian artery followed their normal course. The aim of the current study is to highlight the clinical impact of the above abnormalities providing useful and practically applicable knowledge to interventional clinicians, thoracic and neck surgeons, since the vast majority of documented cases with an arteria lusoria are clinically silent and in most cases discovered incidentally. Clinical manifestations such as dysphagia, chronic cough, and acute ischaemia to the right upper limb may occur, leading to misinterpretation in radiographic examination and complications during neck and thoracic surgery. Review of the literature was also performed and the embryological background of the aberration is highlighted
Foramen magnum, occipital condyles and hypoglossal canals morphometry: anatomical study with clinical implications
Background: Current study examines morphometric alterations of the foramen magnum (FM), occipital condyles (OCs) and hypoglossal canals (HCs) and highlights all the morphometric parameters of the FM area that present side asymmetry, gender dimorphism and are affected by the ageing.
Materials and methods: One hundred and forty-one (73 male and 68 female) Greek adult dry skulls were examined.
Results: Short and long OCs were detected in 27.7% and 26.2%. A combination of short OCs and long HCs was presented in 27.5%. A complete septum was found in 23.6% of the HCs and osseous spurs in 12.9%. Side asymmetry was detected regarding the HCs length (p = 0.046), the maximum extracranial (p = 0.001) and minimum intracranial (p = 0.001) diameters. Mean FM anteroposterior and transverse diameters, FM perimeter and FM surface area were significantly larger in male than in female skulls (p = 0.001 for each parameter). Similarly, the OCs length (right, p = 0.004 and left, p = 0.024) and width (right, p = 0.008 and left, p = 0.006) the left distance HC-OC posterior border (p = 0.048), the anterior (p = 0.011) and posterior (p = 0.001) intercondylar distances and the HCs right length (p = 0.046) were significantly greater in males. A significant decrease was observed with ageing in FM anteroposterior diameter (p = 0.038), FM surface area (p = 0.05), anterior intercondylar distance (p = 0.014) and HC-OC posterior border (p = 0.013).
Conclusions: The study confirmed that only specific HC dimensions showed side asymmetry (HCs maximum extracranial and minimum intracranial diameters and HCs length), gender dimorphism (HCs right length and left distance HC-OC posterior border) and age influence (HC-OC posterior border and HC left extracranial minimum diameter) among young, adults and elderly individuals. FM and OCs dimensions presented gender dimorphism and the age influenced only FM anteroposterior diameter and surface area and the anterior intercondylar distance. The safe zone of OCs drilling in Greeks, calculated by the distance HC-OC posterior border represents the maximum HC depth and is among the lowest values reported in the literature. The significant decrease of this distance with ageing confirms the existence of a drilling safe zone for young, adults and elder individuals. Regarding OCs length, the same probability exists dealing with a short or a long OC during condylectomy. Before planning a transcondylar approach, the coexistence of short OCs and long HCs should be taken into account. These outcomes will be useful for a safe surgery in the craniocervical region in Greeks
Bilateral lingualâfacial trunk: anatomic and clinical implications
Common origin of lingual and facial artery is a relatively frequent anatomic variaÂtion. Instead, bilateral lingualâfacial trunk has been described only sparsely in the literature. In this report authors describe and analyse a case of bilateral common lingualâfacial trunk in the context of its anatomical, clinical and embryological implications. We also describe possible consequences in performance of elective and emergent surgical operations and modification in surgical techniques that should be considered. We believe that surgeons should be suspicious for this variationâs existence and keep alternative solutions in their armentarium
Morphological parameters of the acromion
The purpose of this study was to record the basic morphometric values of the
acromion. Forty-four pairs of dried scapulas were reviewed. Acromial shape
was evaluated in relation to sex, symmetry and presence of subacromial enthesophytes
and classified according to Bigliani with the following results: type I
(flat): 26.1%, type II (curved): 55.6% and type III (hooked): 18.1%. There was
a greater percentage of type III in men (56.2% vs. 43.7%) and type I in women
(56.5% vs. 43.4%). Acromial morphology was symmetric in 29 acromia (65.9%).
Enthesophytes were most common in type III (75%). A rough inferior surface of
the acromion was most frequently found in type III (81.2%). Nine other scapular
osteological parameters were also measured. Many differences were noted
between male and female scapulae. The great variety of morphological features
is assumed to be related to rotator cuff pathology and other shoulder
impairments
Foramina of the anterior mandible in dentate and edentulous mandibles
The study provides a morphometric analysis of the foramina located at the anterior mandible according to dental status. The inner surface from the midline to the distal border of the second premolars of 70 dentate and 27 edentulous Greek adult dry mandibles was investigated. The lingual foramina were divided into medial and lateral foramina. Foramina located at the alveolar process and the midline were subdivided according to their location to genial tubercles. Moreover, the height of the mandible in the genial symphysis and the distances from the foramina to the alveolar crest and the lower border of the mandible were measured. Medial and lateral lingual foramina were presented in 97.9% and 78.4% of the mandibles, respectively. The alveolar medial and lateral lingual foramina were detected in 19.6% and 27.3%, respectively. The mean height of the genial symphysis was 32.06 ± ± 4.88 mm for the dentate and 23.87± 5.37 mm for the edentulous mandibles. The meticulous knowledge of the topography of the lingual foramina and their content is of paramount importance for dentists, oral and maxillofacial surgeons during dental implants placement. Middle and lateral lingual foramina are constant structures, while the alveolar foramina presented only in dentate mandibles. The foramina location is directly affected by dental status. The morphology of edentulous mandibles increases the risk of intraoperative complications at the anterior mandible.
The size of the foramen ovale regarding to the presence and absence of the emissary sphenoidal foramen: is there any relationship between them?
Background: The study investigates the size of the foramen ovale (FO) in relation to the presence and absence of the emissary sphenoidal foramen (ESF). Any possible alteration of the FO size in relation to the ESF (unilateral or bilateral) presence and absence was also examined.
Materials and methods: One-hundred and ninety-five (117 male and 78 female) Greek adult dry skulls were investigated.
Results: The ESF was present in 40% of the skulls (21.5% bilaterally and 18.5% unilaterally). No statistical significant difference was detected between ESF presence or absence and its unilateral or bilateral occurrence. The ESF existence had no relation to the FO size.
Conclusions: The ESF absence or presence has no effect on FO size. The emissary sphenoidal vein is an additional venous pathway connecting cavernous sinus with the pterygoid venous plexus. These findings enhance that the venous plexus of the FO is a constant trait. The meticulous knowledge of the middle cranial fossa anatomy is of paramount importance during transovale procedures, as the outcome of cannulation may be affected by the existence of ESF, the confluence FO-ESF, the existence of osseous spurs and bridging into the FO. (Folia Morphol 2018; 77, 1: 90â98)
Persistent median artery in the carpal tunnel: anatomy, embryology, clinical significance, and review of the literature
The median artery usually regresses after the eighth week of intrauterine life, but
in some cases it persists into adulthood. The persistent median artery (PMA) passes
through the carpal tunnel of the wrist, accompanying the median nerve.
During anatomical dissection in our department, we found two unilateral cases
of PMA originating from the ulnar artery. In both cases the PMA passed through
the carpal tunnel, reached the palm, and anastomosed with the ulnar artery,
forming a medio-ulnar type of superficial palmar arch. In addition, in both cases
we observed a high division of the median nerve before entering the carpal
tunnel. Such an artery may result in several complications such as carpal tunnel
syndrome, pronator syndrome, or compression of the anterior interosseous nerve.
Therefore, the presence of a PMA should be taken into consideration in clinical
practice. This study presents two cases of PMA along with an embryological
explanation, analysis of its clinical significance, and a review of the literature. The
review of the literature includes cases observed during surgical procedures or
anatomical dissections. Cases observed by means of imaging techniques were
not included in the study
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