217 research outputs found
Median aperture of the fourth ventricle revisited
Background: The median aperture of Magendie is the largest of three openings
of the fourth ventricle and thus it forms the main path for the outflow of
the cerebrospinal fluid from the ventricle. The Magendie aperture connects the
fourth ventricle with the cisterna magna and makes a natural corridor for neurosurgical
approach and inspection of the ventricle and its floor. The purpose
of this study was to give a contemporary anatomical view of this structure in
the context of historical data.
Material and methods: The Magendie foramen was studied in 30 fixed specimens
of human brainstems with cerebella. The microdissection technique
was used. Measurements were taken with a microscope ocular ruler.
Results: The aperture is limited by the following structures: obex and gracile
tubercles inferiorly, and tela choroidea with choroid plexus superolaterally. Obex
tubercles usually have the form of a piece of neural tissue bridging two halves
of the brainstem above the entrance to the central canal. Gracile tubercles
together are 8.15 mm wide and the maximal width of the foramen is 6.53 mm.
Tela choroidea attaches laterally at both sides to the inferior medullary velum.
In most cases the right and left choroid plexus are connected to each other
with a triangular membrane of tela choroidea, which protrudes through the
median foramen and attaches to the vermis at a highly variable level.
Conclusions: We hope that the presented description of anatomical relations
around the Magendie aperture, with its new measurements, will be helpful for
those operating in the area and will explain some of the inaccuracies found in
literature. (Folia Morphol 2011; 70, 2: 84–90
The anatomy of the fundic branches of the stomach: preliminary results
The fundic branches of the stomach can be defined as a group of vessels that
can arise either directly or indirectly from the following source arteries: the left
inferior phrenic artery, the accessory left hepatic artery, the left gastric artery,
the left middle suprarenal artery, the main trunk of the splenic artery, the posterior
gastric artery, the superior polar artery, the gastrosplenic artery, the left
gastroepiploic artery and the splenic artery with its inferior and superior terminal
branches. It is worth mentioning that the fundic branches of the left gastroepiploic
artery and the superior and inferior terminal branches of the splenic
artery, like other vessels arising from these three source arteries and supplying
the stomach, are defined as short gastric arteries.
The anatomy of these fundic branches, particularly relevant to some surgical
procedures, is not sufficiently described, and the current literature suffers from
lack of publications on this particular topic. We therefore decided to explore in
detail the arterial vascularisation of the gastric fundus.
The research was carried out on material consisting of 15 human stomach
specimens. The anatomical analysis comprised the following: the number of
occurrences of fundic branches in each of the source arteries defined above,
the distance between the origins of the source artery and its arising fundic
branch, the way in which the fundic branches arose, the length, diameter at
point of origin and morphology of the fundic braches, as well as the exact
point of perforation of each fundic branch on the fundus.
The highest incidence of the direct-branching pattern of fundic branches was
in the left middle suprarenal artery, the gastrosplenic artery and the left gastrosplenic
artery. The accessory left hepatic artery, the left gastric artery and the
main trunk of the splenic artery were the most frequent site of the indirectly
arising pattern of fundic branch. The highest median value of fundic branch
length was 63.05 mm, found in the accessory left hepatic artery group. The
largest median diameter value of the vessel was encountered among those
originating in the left middle suprarenal artery and reached 2.17 mm. The
posterolateral quadrant of the fundus received the largest number of fundic
branches, amounting to 46.5% of all the fundic branches studied. (Folia Morphol
2008; 67: 120–125
ОБЗОР СЕМАНТИКИ ЯЗЫКА HTML 5
HTML5 несет в себе множество изменений разного уровня и разной важности. Принципиально, ключевые изменения можно разделить на 5 блоков: семантика, мультимедиа, динамичная графика, веб-формы, JavaScript APls. В данной статье рассмотрен обзор семантики HTML5 в котором появился ряд новых семантических тегов, позволяющих более осмысленно организовывать внутреннюю структуру веб-страни
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Novel Tertiary Amine Solid Adsorbents Used for the Capture of Carbon Dioxide
Standard clinical computed tomography fails to precisely visualise presence, course and branching points of deep cerebral perforators
Background: Standard computed tomography (CT) images have earned a well-established position in neuroimaging. Despite that, CT is somehow limited by its resolution, which does not enable to distinctively visualize structures smaller than 300 um in diameter. Perforating arteries, most of which measure 100-400 um in diameter, supply important subcortical structures (thalamus, basal ganglia, internal capsule). Consequently, pathologies affecting these vessels (e.g. lacunar strokes) can have a devastating clinical outcome. The aim of our study was to assess standard CT’s ability to visualize perforators and compare it with microscopical and micro-CT pictures. Materials and methods: We have obtained six brainstem and seventeen basal ganglia specimens. We infused them with barium sulphate contrast medium administered into either vertebral or internal cerebral artery. After that, the specimens were fixed in formalin and subsequently a series of CT, micro-CT and microscopical examinations were performed. Results: The median number of visualized perforators in brainstem and basal ganglia specimens was 8 and 3, respectively for CT and 18 and 7 for micro–CT (p < 0.05). Standard CT failed to clearly visualize branching points and vessels smaller than 0.25-0.5 mm (1-2 voxels) in diameter. Parallel vessels, like lenticulostriate arteries could not be differentiated in standard CT due to their proximity being smaller that the resolution. Conclusions: Basing on our results, we infer that CT is a poor modality for imaging of the perforators, presenting both quantitative and qualitative flaws in contrast with micro-CT
Search for inelastic dark matter with the CDMS II experiment
Results are presented from a reanalysis of the entire five-tower data set
acquired with the Cryogenic Dark Matter Search (CDMS II) experiment at the
Soudan Underground Laboratory, with an exposure of 969 kg-days. The analysis
window was extended to a recoil energy of 150 keV, and an improved
surface-event background-rejection cut was defined to increase the sensitivity
of the experiment to the inelastic dark matter (iDM) model. Three dark matter
candidates were found between 25 keV and 150 keV. The probability to observe
three or more background events in this energy range is 11%. Because of the
occurrence of these events the constraints on the iDM parameter space are
slightly less stringent than those from our previous analysis, which used an
energy window of 10-100 keV.Comment: 10 pages, 10 figures, minor changes to match published version,
conclusion unchange
A Search for WIMPs with the First Five-Tower Data from CDMS
We report first results from the Cryogenic Dark Matter Search (CDMS II)
experiment running with its full complement of 30 cryogenic particle detectors
at the Soudan Underground Laboratory. This report is based on the analysis of
data acquired between October 2006 and July 2007 from 15 Ge detectors (3.75
kg), giving an effective exposure of 121.3 kg-d (averaged over recoil energies
10--100 keV, weighted for a weakly interacting massive particle (WIMP) mass of
60 \gev). A blind analysis, incorporating improved techniques for event
reconstruction and data quality monitoring, resulted in zero observed events.
This analysis sets an upper limit on the WIMP-nucleon spin-independent cross
section of 6.6 cm (4.6 cm when combined
with previous CDMS Soudan data) at the 90% confidence level for a WIMP mass of
60 \gev. By providing the best sensitivity for dark matter WIMPs with masses
above 42 GeV/c, this work significantly restricts the parameter space for
some of the favored supersymmetric models.Comment: 5 pages, 4 figures, submitted to PRL 28 March 200
Results from a Low-Energy Analysis of the CDMS II Germanium Data
We report results from a reanalysis of data from the Cryogenic Dark Matter
Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken
between October 2006 and September 2008 using eight germanium detectors are
reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased
sensitivity to interactions from Weakly Interacting Massive Particles (WIMPs)
with masses below ~10 GeV/c^2. This analysis provides stronger constraints than
previous CDMS II results for WIMP masses below 9 GeV/c^2 and excludes parameter
space associated with possible low-mass WIMP signals from the DAMA/LIBRA and
CoGeNT experiments.Comment: 9 pages, 8 figures. Supplemental material included as ancillary
files. v3) Added appendix with additional details regarding energy scale and
background
First Test Results of the Trans-Impedance Amplifier Stage of the Ultra-fast HPSoC ASIC
We present the first results from the HPSoC ASIC designed for readout of
Ultra-fast Silicon Detectors. The 4-channel ASIC manufactured in 65 nm CMOS by
TSMC has been optimized for 50 um thick AC-LGAD. The evaluation of the analog
front end with \b{eta}-particles impinging on 3x3 AC-LGAD arrays (500 um pitch,
200x200 um2 metal) confirms a fast output rise time of 600 ps and good timing
performance with a jitter of 45 ps. Further calibration experiments and TCT
laser studies indicate some gain limitations that are being investigated and
are driving the design of the second-generation pre-amplification stages to
reach a jitter of 15 ps.Comment: 7 pages, 6 figure
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