1,179 research outputs found
Management of jugular bulb injury during drilling of the internal auditory canal (ICA) for vestibular schwannoma surgery
The retrosigmoid approach for vestibular schwannoma surgery has remained the standard approach by most neurosurgeons. Drilling the posterior wall of the internal auditory meatus (IAM) is an essential step in removing the intrameatal tumor. During IAM drilling, three anatomical structures can be encountered, including the posterior semicircular canal, vestibular aqueduct, and jugular bulb. Any of these can be injured during drilling, especially if the jugular bulb lies above the inferior edge of the IAM. Although IAM drilling is performed in most vestibular schwannoma surgeries, information on how to manage complications such as jugular bulb injury is lacking. Here we use an intraoperative video to demonstrate how to manage the inadvertent injury to the jugular bulb in order to avoid massive blood loss. We present a case of a 39-year-old woman with hearing loss, diagnosed with a cerebellopontine angle mass extending into the IAM. Surgery was required due to tumor progression. We used the retrosigmoid approach to access the tumor. During IAM drilling, the jugular bulb was injured. A thin layer of bone wax was applied under continuous suction. The margins of the wax were then gently compressed with a dissector; great care was taken to avoid pushing the wax into the jugular bulb. Excess bone wax was removed (video 1). A small diamond drill (2 mm) was used for further drilling. Our instructional video shows the surgical approach, microsurgical anatomy, and technical aspects of managing massive bleeding from jugular bulb injury. It should therefore be helpful for young neurosurgeons.Non peer reviewe
KausivÀestö Kymenlaaksossa:vapaa-ajan asukkaiden ja matkailijoiden liikkumistarpeisiin vastaaminen
TiivistelmÀ. Vapaa-ajan asuminen on merkittÀvÀ ilmiö Suomessa. Se koskettaa miljoonia suomalaisia ja on oleellinen osa suomalaista identiteettiÀ. TÀmÀ tutkimus on vapaa-ajan asumiseen keskittyvÀ tapaustutkimus Kymenlaakson alueelta. Tutkimuksessa selvitetÀÀn, miten vapaa-ajan asuminen nÀkyy Kymenlaaksossa ja miten sen huomioiminen vaikuttaa alueen vÀestönkehityksen kuvaan. Vapaa-ajan asumiseen liittyy paljon liikkumista. Alueellisten liikennejÀrjestelmien suunnittelun pohjana on usein tilastoitu vÀestö ja siksi kausittaisen vÀestön liikkumistarpeet jÀÀvÀt suunnittelussa huomiotta. Kuitenkin myös kausivÀestöllÀ on liikkumistarpeita kohde alueella. TÀssÀ tutkimuksessa selvitetÀÀn vapaa-ajan asukkaiden ja kesÀvierailijoiden liikkumistapoja ja tarpeita Kymenlaakson alueella ja pohditaan miten alueellisia liikennepalveluita voisi kehittÀÀ vastaamaan nÀihin tarpeisiin.
KausivÀestön liikkumistapoja ja -tarpeita sekÀ liikennepalveluihin kohdistuvia kehitysideoita selvitetÀÀn kesÀn 2019 aikana kerÀtyn kyselyaineiston avulla. KausivÀestön liikkumistapoja ja -tarpeita myös vertaillaan alueella vakituisesti asuvien ihmisten liikkumistapoihin. Vakituisen vÀestön liikkumistavoista tietoa saadaan Kymenlaakson alueella kevÀÀllÀ 2019 toteutetusta liikkumistutkimuskyselystÀ. Kyselyiden vastauksia tarkastellaan ja analysoidaan sekÀ QGIS-ohjelmistolla ettÀ Microsoft Excel -taulukkolaskentaohjelmassa ja IBM SPSS Statistics -ohjelmistolla. Kausiasumisen ilmiöitÀ ja sen vaikutuksia vÀestödynamiikkaan tarkastellaan YKR-ruutuihin pohjaavien laskelmien kautta.
Tutkimuksen mukaan vapaa-ajan asuminen keskittyy tutkimusalueella pitkÀlti Pohjois-Kymenlaaksoon ja painottuu kesÀaikaan. Vapaa-ajan asuminen vaikuttaa merkittÀvÀsti etenkin maaseutualueiden vÀestöpohjaan. Maaseuduilla vÀestö lisÀÀntyy kausittain huomattavasti ja kausiasukkaiden huomioiminen vÀestölaskelmissa muuttaa vÀestönkehityksen kuvaa tutkimusalueella. Vakituisen vÀestön ja kausittaisen vÀestön liikkumistapojen vÀlillÀ ei ole suurta eroa. Molemmat liikkuvat pÀÀsÀÀntöisesti omalla autolla. Vaikka kausivÀestön liikkuminen pohjaa pitkÀlti yksityisautoiluun, on heillÀ myös kiinnostusta julkisia liikennepalveluita kohtaan ja liikennepalveluiden kehittÀminen koetaan tÀrkeÀksi. KausivÀestön liikkuminen keskittyy Kouvolan keskustan, Pohjois-Kymenlaakson mökkialueiden sekÀ muutamien tutkimuksessa havaittujen suosittujen kohteiden/palveluiden vÀlille. Erityisesti liikennepalveluita tulisi kehittÀÀ Kouvolan keskustan ja syrjÀisten mökkialueiden vÀlille. KausivÀestön liikkumistarpeisiin Kymenlaaksossa voitaisiin vastata esimerkiksi kimppakyyti-jÀrjestelyillÀ tai erilaisilla kutsupohjaisilla liikennepalveluilla. Tutkimuksessa osoitettiin kausiasukkaiden huomioimisen tÀrkeys liikennesuunnittelussa syrjÀisillÀ maaseutualueilla, joilla yleisesti liikenteen jÀrjestÀminen on koettu hankalaksi
Tulvien aiheuttamat seuraukset ja niihin vaikuttavat tekijÀt:tapausesimerkkeinÀ Kiinan tulva, Pohjanmeren tulva ja Porin kaupunkitulva
TiivistelmÀ. TÀssÀ tutkimuksessa perehdytÀÀn aikaisemman kirjallisuuden pohjalta tulvien seurauksiin ja niihin vaikuttaviin tekijöihin. LisÀksi eri tulvatyyppejÀ kuvastavien esimerkkitapauksien kautta perehdyn tarkemmin eri tulvatyyppien seurauksiin. Vesistötulvaa edustaa vuonna 1931 tapahtunut tulva Kiinassa, meritulvaa vuonna 1953 tapahtunut Pohjanmeren tulva ja hulevesitulvaa Porissa vuonna 2007 sattunut kaupunkitulva.
Tulva on vallitsevista luonnonoloista johtuva luonnonilmiö. Tulvat voidaan jakaa kolmeen eri kategoriaan; vesistötulviin, meritulviin ja hulevesitulviin. Vesistötulvat syntyvÀt vesistöjen, eli jokien ja jÀrvien, vedenpinnan noustessa, meritulvat syntyvÀt merenpinnan noustessa normaalin vaihtelun ylÀpuolelle ja hulevesitulvat puolestaan syntyvÀt, kun hulevesirakenteiden, kuten viemÀriverkostojen ja avo-ojien, kapasiteetti ylittyy runsaan sateen seurauksena. Tulvat voivat aiheuttaa vahingollisia seurauksia esimerkiksi ihmisten terveydelle ja turvallisuudelle, ympÀristölle, infrastruktuurille, taloudelliselle toiminnalle ja kulttuuriperinnölle. Seuraukset voidaan luokitella suoriin, epÀsuoriin, aineellisiin ja aineettomiin seurauksiin. Suorat seuraukset syntyvÀt vÀlittömÀstÀ kosketuksesta tulvaveden kanssa. EpÀsuorat seuraukset puolestaan ovat pidemmÀn aikavÀlin seurauksia, jotka ovat vÀlillisesti yhteydessÀ itse tulvaan. Aineellisille seurauksille voidaan laskea rahallinen arvo, kun taas aineettomia seurauksia puolestaan ei voida mitata rahassa.
Tulvat tuhoavat rakennuksia, omaisuutta, satoja ja karjaa. Ne usein aiheuttavat katkoksia infrastruktuurissa ja pilaavat maaperÀÀ. Tulvilla on myös merkittÀvÀ vaikutus ihmisiin kuolemantapausten, loukkaantumisien ja jÀlkikÀteen ilmenevien psyykkisten hÀiriöiden kautta. Tulvan seurauksiin vaikuttaa tulvan luonteenomaiset piirteet, alueen ominaispiirteet ja vÀestön sosiaaliset ominaisuudet. Esimerkiksi ajankohta, kesto, syvyys, topografia, vallitseva ilmasto, urbanisaation taso sekÀ vÀestön ikÀ ja rakenne. Yksi merkittÀvimmistÀ vaikuttavista tekijöistÀ on yhteiskunnan varautuminen ja valmius
Theory of the Half-Polarized Quantum Hall States
We report a theoretical analysis of the half-polarized quantum Hall states
observed in a recent experiment. Our numerical results indicate that the ground
state energy of the quantum Hall and states versus spin
polarization has a downward cusp at half the maximal spin polarization. We map
the two-component fermion system onto a system of excitons and describe the
ground state as a liquid state of excitons with non-zero values of exciton
angular momentum.Comment: 4 pages (RevTeX), 3 figures (PostScript), added reference
Understanding behavioural responses to human-induced rapid environmental change: a meta-analysis
Behavioural responses are often the first reaction of an organism to human-induced rapid environmental change (HIREC), yet current empirical evidence provides no consensus about the main environmental features that animals respond to behaviourally or which behaviours are responsive to HIREC. To understand how changes in behaviour can be predicted by different forms of HIREC, we conducted a meta-analysis of the existing empirical literature focusing on behavioural responses to five axes of environmental change (climate change, changes in CO2, direct human impact, changes in nutrients and biotic exchanges) in five behavioural domains (aggression, exploration, activity, boldness and sociability) across a range of taxa but with a focus on fish and bird species. Our meta-analysis revealed a general absence of directional behavioural responses to HIREC. However, the absolute magnitude of the effect sizes was large. This means that animals have strong behavioural responses to HIREC, but the responses are not clearly in any particular direction. Moreover, the absolute magnitude of the effect sizes differed between different behaviours and different forms of HIREC: Exploration responded more strongly than activity, and climate change induced the strongest behavioural responses. Model heterogeneities identified that effect sizes varied primarily because of study design, and the specific sample of individuals used in a study; phylogeny also explains significant variation in our bird model. Based on these results, we make four recommendations to further our understanding: 1) a more balanced representation of laboratory and field studies, 2) consideration of context dependency, 3) standardisation of the methods and definitions used to quantify and study behaviours and 4) consideration of the role for individual differences in behaviour. © 2021 Nordic Society Oikos. Published by John Wiley & Sons LtdPeer reviewe
Size and location of radish 1 chromosome regions carrying the fertility restorer Rfk1 gene in spring turnip rape
In spring turnip rape (Brassica rapa L. spp. oleifera) the most promising F1
hybrid system would be the Ogu-INRA CMS/Rf system. A Kosena fertility restorer
gene Rfk1, homologue of the Ogura restorer gene Rfo, was successfully
transferred from oilseed rape into turnip rape and that restored the fertility
in female lines carrying Ogura cms. The trait was, however, unstable in
subsequent generations. The physical localization of the radish chromosomal
region carrying the Rfk1 gene was investigated using 8 GISH (genomic in situ
hybridization) and BAC-FISH (bacterial artificial chromosome fluorescence in
situ hybridization) methods. The metaphase chromosomes were hybridized using
radish DNA as the genomic probe and BAC64 probe, which is linked with Rfo gene.
Both probes showed a signal in the chromosome spreads of the restorer line
4021-2 Rfk of turnip rape but not in the negative control line 4021B. The GISH
analyses clearly showed that the turnip rape restorer plants were either
monosomic (2n=2x=20+1R) or disomic (2n=2x=20+2R) addition lines with one or two
copies of a single alien chromosome region originating from radish. In the
BAC-FISH analysis, double dot signals were detected in sub-terminal parts of
the radish chromosome arms showing that the fertility restorer gene Rfk1 was
located in this additional radish chromosome. Detected disomic addition lines
were found to be unstable for turnip rape hybrid production. Using the BAC-FISH
analysis, weak signals were sometimes visible in two chromosomes of turnip rape
and a homologous region of Rfk1 in chromosome 9 of the B. rapa A genome was
verified with BLAST analysis. In the future this homologous area in A genome
could be substituted with radish chromosome area carrying the Rfk1 gene.Comment: "The final publication is available at http://www.springerlink.com".
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author's accepted version. ... Acknowledgement ... accompanied by the text
"The final publication is available at http://www.springerlink.com
Lymphatic vessels are present in human saccular intracranial aneurysms
Saccular intracranial aneurysm (sIA) rupture leads to subarachnoid haemorrhage and is preceded by chronic inflammation and atherosclerotic changes of the sIA wall. Increased lymphangiogenesis has been detected in atherosclerotic extracranial arteries and in abdominal aortic aneurysms, but the presence of lymphatic vessels in sIAs has remained unexplored. Here we studied the presence of lymphatic vessels in 36 intraoperatively resected sIAs (16 unruptured and 20 ruptured), using immunohistochemical and immunofluorescence stainings for lymphatic endothelial cell (LEC) markers. Of these LEC-markers, both extracellular and intracellular LYVE-1-, podoplanin-, VEGFR-3-, and Prox1-positive stainings were detected in 83%, 94%, 100%, and 72% of the 36 sIA walls, respectively. Lymphatic vessels were identified as ring-shaped structures positive for one or more of the LEC markers. Of the sIAs, 78% contained lymphatic vessels positive for at least one LEC marker. The presence of LECs and lymphatic vessels were associated with the number of CD68+ and CD163+ cells in the sIA walls, and with the expression of inflammation indicators such as serum amyloid A, myeloperoxidase, and cyclo-oxygenase 2, with the presence of a thrombus, and with the sIA wall rupture. Large areas of VEGFR-3 and alpha-smooth muscle actin (alpha SMA) double-positive cells were detected in medial parts of the sIA walls. Also, a few podoplanin and alpha SMA double-positive cells were discovered. In addition, LYVE-1 and CD68 double-positive cells were detected in the sIA walls and in the thrombus revealing that certain CD68+ macrophages are capable of expressing LEC markers. This study demonstrates for the first time the presence of lymphatic vessels in human sIA walls. Further studies are needed to understand the role of lymphatic vessels in the pathogenesis of sIA.Peer reviewe
Assessing the Nature of Lipid Raft Membranes
The paradigm of biological membranes has recently gone through a major update. Instead of being fluid and homogeneous, recent studies suggest that membranes are characterized by transient domains with varying fluidity. In particular, a number of experimental studies have revealed the existence of highly ordered lateral domains rich in sphingomyelin and cholesterol (CHOL). These domains, called functional lipid rafts, have been suggested to take part in a variety of dynamic cellular processes such as membrane trafficking, signal transduction, and regulation of the activity of membrane proteins. However, despite the proposed importance of these domains, their properties, and even the precise nature of the lipid phases, have remained open issues mainly because the associated short time and length scales have posed a major challenge to experiments. In this work, we employ extensive atom-scale simulations to elucidate the properties of ternary raft mixtures with CHOL, palmitoylsphingomyelin (PSM), and palmitoyloleoylphosphatidylcholine. We simulate two bilayers of 1,024 lipids for 100 ns in the liquid-ordered phase and one system of the same size in the liquid-disordered phase. The studies provide evidence that the presence of PSM and CHOL in raft-like membranes leads to strongly packed and rigid bilayers. We also find that the simulated raft bilayers are characterized by nanoscale lateral heterogeneity, though the slow lateral diffusion renders the interpretation of the observed lateral heterogeneity more difficult. The findings reveal aspects of the role of favored (specific) lipidâlipid interactions within rafts and clarify the prominent role of CHOL in altering the properties of the membrane locally in its neighborhood. Also, we show that the presence of PSM and CHOL in rafts leads to intriguing lateral pressure profiles that are distinctly different from corresponding profiles in nonraft-like membranes. The results propose that the functioning of certain classes of membrane proteins is regulated by changes in the lateral pressure profile, which can be altered by a change in lipid content
Integral and fractional Quantum Hall Ising ferromagnets
We compare quantum Hall systems at filling factor 2 to those at filling
factors 2/3 and 2/5, corresponding to the exact filling of two lowest electron
or composite fermion (CF) Landau levels. The two fractional states are examples
of CF liquids with spin dynamics. There is a close analogy between the
ferromagnetic (spin polarization P=1) and paramagnetic (P=0) incompressible
ground states that occur in all three systems in the limits of large and small
Zeeman spin splitting. However, the excitation spectra are different. At
filling factor 2, we find spin domains at half-polarization (P=1/2), while
antiferromagnetic order seems most favorable in the CF systems. The transition
between P=0 and 1, as seen when e.g. the magnetic field is tilted, is also
studied by exact diagonalization in toroidal and spherical geometries. The
essential role of an effective CF-CF interaction is discussed, and the
experimentally observed incompresible half-polarized state is found in some
models
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