Serum proteomics of glioma: methods and applications

The prognosis of patients with glioblastoma, the most malignant adult glial brain tumor, remains poor in spite of advances in treatment procedures, including surgical resection, irradiation and chemotherapy.Genetic heterogeneity of glioblastoma warrants extensive studies in order to gain a thorough understanding of the biology of this tumor. While there have been several studies of global transcript profiling of glioma with the identification of gene signatures for diagnosis and disease management, translation into clinics is yet to happen. Serum biomarkers have the potential to revolutionize the process of cancer diagnosis, grading, prognostication and treatment response monitoring. Besides having the advantage that serum can be obtained through a less invasive procedure, it contains molecules at an extraordinary dynamic range of ten orders of magnitude in terms of their concentrations. While the conventional methods, such as 2DE, have been in use for many years, the ability to identify the proteins through mass spectrometry techniques such as MALDI-TOF led to an explosion of interest in proteomics. Relatively new high-throughput proteomics methods such as SELDI-TOF and protein microarrays are expected to hasten the process of serum biomarker discovery. This review will highlight the recent advances in the proteomics platform in discovering serum biomarkers and the current status of glioma serum markers. We aim to provide the principles and potential of the latest proteomic approaches and their applications in the biomarker discovery process. Besides providing a comprehensive list of available serum biomarkers of glioma, we will also propose how these markers will revolutionize the clinical management of glioma patients.

Studies on boundary lubrication properties of oxidised coconut and soy bean oils

Vegetable oils are a potential source of base oils for biodegradable lubricants, with limited oxidative stability. This study focuses on the effect of long-term ageing and the influence of oxidation products on the boundary lubrication performance of coconut and soy bean oils, by subjecting them to accelerated ageing in a dark oven at elevated temperature. The samples were collected at regular intervals and analysed for the changes in viscosity, percentage of free fatty acid and peroxide number compared to fresh oil samples. The boundary lubrication properties of these samples were evaluated using a four-ball tester. Increased wear observed with aged oil samples was linked to the destruction of triglyceride structure and formation of peroxides. The difference in the wear properties of soy bean oil to coconut oil was accounted by its high content of unsaturated fatty acids and its susceptibility to undergo oxidation. It was concluded that the coconut oil can perform as a better lubricant and has got a better storage life compared to soy bean oil.

Determination of skin friction in strong pressure-gradient equilibrium and near-equilibrium turbulent boundary layers

The conventional Clauser-chart method for determination of local skin friction in zero or weak pressure-gradient turbulent boundary layer flows fails entirely in strong pressure-gradient situations. This failure occurs due to the large departure of the mean velocity profile from the universal logarithmic law upon which the conventional Clauser-chart method is based. It is possible to extend this method,even for strong pressure-gradient situations involving equilibrium or near-equilibrium turbulent boundary layers by making use of the so-called non-universal logarithmic laws. These non-universal log laws depend on the local strength of the pressure gradient and may be regarded as perturbations of the universal log law.The present paper shows that the modified Clauser-chart method, so developed, yields quit satisfactory results in terms of estimation of local skin friction in strongly accelerated or retarded equilibrium and near-equilibrium turbulent boundary layers that are not very close to relaminarization or separation.

Crystallization kinetics of SrBi2B2O7 glasses by non-isothermal methods

Transparent glasses of SrBi2B2O7 (SBBO) were fabricated via the conventional melt-quenching technique. The amorphous and the glassy nature of the as-quenched samples were, respectively, confirmed by X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC). The glass transition (T (g)) and the crystallization parameters [crystallization activation energy (E (cr)) and Avrami exponent (n)] were evaluated under non-isothermal conditions using DSC. There was a close agreement between the activation energies for the crystallization process determined by Augis and Bennet and Kissinger methods. The variation of local activation energy [E (c)(x)] that was determined by Ozawa method, decreased with the fraction of crystallization (x). The Avrami exponent (n(x)) increased with the increase in fraction of crystallization (x) suggesting that there was a change over in the crystallization process from the surface to the bulk.

Postoperative soft tissue defects in the ankle area : The etiology and methods of reconstruction

The risk is obvious for soft tissue complications after operative treatment of the Achilles tendon, calcaneal bone or after ankle arthroplasty. Such complications after malleolar fractures are, however, seldom seen. The reason behind these complications is that the soft tissue in this region is tight and does not allow much tension to the wound area after surgery. Furthermore the area of operation may be damaged by swelling after the injury, or can be affected by peripheral vascular disease. While complications in this area are unavoidable, they can be diminished. This study attempts to highlight the possible predisposing factors leading to complications in these operations and on the other hand, to determine the solutions to solve soft tissue problems in this region. The study consists of five papers. The first article is a reprint on the soft tissue reconstruction of 25 patients after their complicated Achilles tendon surgeries were analysed. The second study reviews a series of 126 patients after having undergone an operative treatment of calcaneal bone fractures and analyses the complications and possible reasons behind them. The third part analyses a series of corrections of 35 soft tissue complications after calcaneal fracture operations. The fourth part reviews a series of 7 patients who had undergone complicated ankle arthroplasties. The last article presents a series of post operative lateral defects of the ankle treated with a less frequently used distally based peroneus brevis muscle flap and analyses the results. What can be conducted from these studies is that in general, the results after the correction of even severe soft tissue complications in the ankle region are good. For the small defects around the Achilles tendon, the local flaps are useful, but the larger defects are best treated with a free flap. We found that a long delay from trauma to surgery and a long operating time were predisposing factors that lead to soft tissue complications after operatively treated calcaneal bone fractures. The more severe the injury, the greater the risk for wound complication. Surprisingly, the long-term results after infected calcaneal osteosyntheses were acceptable and the calcaneal bone seems to tolerate chronic infections very well if the soft tissue is reconstructed successfully. Behind the complicated ankle arthroplasties, unexpectedly high number of cases experiencing arteriosclerosis of the lower extremity was found. These complications lead to ankle fusion but can be solved with a free flap if the vascularity is intact or can be reconstructed. For this reason a vascular examination of the lower extremity arteries of the patients going to ankle arthroplasty is strongly recommended. Moreover postoperative lateral malleolar wound infections which typically create lateral ankle defects can successfully be treated with a peroneus brevis muscle flap covered with a free skin graft.

Novel surgical and imaging methods of the middle ear and temporal bone

Välikorvaleikkauksiin usein liittyvän välikorvan ja kuuloluuketjun kirurgisen rekonstruktion tavoitteena on luoda olosuhteet, jotka mahdollistavat hyvän kuulon sekä välikorvan säilymisen tulehduksettomana ja ilmapitoisena. Välikorvan rekonstruktiossa on käytetty implanttimateriaaleina perinteisesti potilaan omia kudoksia sekä tarvittaessa erilaisia hajoamattomia biomateriaaleja, mm. titaania ja silikonia. Ongelmana biomateriaalien käytössä voi olla bakteerien adherenssi eli tarttuminen vieraan materiaalin pintaan, mikä saattaa johtaa biofilmin muodostumiseen. Tämä voi aiheuttaa kroonisen, huonosti antibiootteihin reagoivan infektion kudoksessa, mikä usein käytännössä johtaa uusintaleikkaukseen ja implantin poistoon. Maitohappo- ja glykolihappopohjaiset biologisesti hajoavat polymeerit ovat olleet kliinisessä käytössä jo vuosikymmeniä. Niitä on käytetty erityisesti tukimateriaaleina mm. ortopediassa sekä kasvo- ja leukakirurgiassa. Niitä ei ole toistaiseksi käytetty välikorvakirurgiassa. Korvan kuvantamiseen käytetään ensisijaisesti tietokonetomografiaa (TT). TT-tutkimuksen ongelmana on potilaan altistuminen suhteellisen korkealle sädeannokselle, joka kasvaa kumulatiivisesti, jos kuvaus joudutaan toistamaan. Väitöskirjatyö selvittää uuden, aiemmin kliinisessä työssä rutiinisti lähinnä hampaiston ja kasvojen alueen kuvantamiseen käytetyn rajoitetun kartiokeila-TT:n soveltuvuutta korvan alueen kuvantamiseen. Väitöskirjan kahdessa ensimmäisessä osatyössä tutkittiin ja verrattiin kahden kroonisia ja postoperatiivisia korvainfektioita aiheuttavan bakteerin, Staphylococcus aureuksen ja Pseudomonas aeruginosan, in vitro adherenssia titaanin, silikonin ja kahden eri biohajoavan polymeerin (PLGA) pintaan. Lisäksi tutkittiin materiaalien albumiinipinnoituksen vaikutusta adherenssiin. Kolmannessa osatyössä tutkittiin eläinmallissa PLGA:n biokompatibiliteettia eli kudosyhteensopivuutta kokeellisessa välikorvakirurgiassa. Chinchillojen välikorviin istutettiin PLGA-materiaalia, eläimiä seurattiin, ja ne lopetettiin 6 kk:n kuluttua operaatiosta. Biokompatibiliteetin arviointi perustui kliinisiin havaintoihin sekä kudosnäytteisiin. Neljännessä osatyössä tutkittiin kartiokeila-TT:n soveltuvuutta korvan alueen kuvantamiseen vertaamalla sen tarkkuutta perinteisen spiraali-TT:n tarkkuuteen. Molemmilla laitteilla kuvattiin ohimo- eli temporaaliluita korvan alueen kliinisesti ja kirurgisesti tärkeiden rakenteiden kuvantumisen tarkkuuden arvioimiseksi. Viidennessä osatyössä arvioitiin myös operoitujen temporaaliluiden kuvantumista kartiokeila-TT:ssa. Bakteeritutkimuksissa PLGA-materiaalin pintaan tarttui keskimäärin korkeintaan saman verran tai vähemmän bakteereita kuin silikonin tai titaanin. Albumiinipinnoitus vähensi bakteeriadherenssia merkitsevästi kaikilla materiaaleilla. Eläinkokeiden perusteella PLGA todettiin hyvin siedetyksi välikorvassa. Korvakäytävissä tai välikorvissa ei todettu infektioita, tärykalvon perforaatioita tai materiaalin esiin työntymistä. Kudosnäytteissä näkyi lievää tulehdusreaktiota ja fibroosia implantin ympärillä. Temporaaliluutöissä rajoitettu kartiokeila-TT todettiin vähintään yhtä tarkaksi menetelmäksi kuin spiraali-TT välikorvan ja sisäkorvan rakenteiden kuvantamisessa, ja sen aiheuttama kertasäderasitus todettiin spiraali-TT:n vastaavaa huomattavasti vähäisemmäksi. Kartiokeila-TT soveltui hyvin välikorvaimplanttien ja postoperatiivisen korvan kuvantamiseen. Tulokset osoittavat, että PLGA on välikorvakirurgiaan soveltuva, turvallinen ja kudosyhteensopiva biomateriaali. Biomateriaalien pinnoittaminen albumiinilla vähentää merkittävästi bakteeriadherenssia niihin, mikä puoltaa pinnoituksen soveltamista implanttikirurgiassa. Kartiokeila-TT soveltuu korvan alueen kuvantamiseen. Sen tarkkuus kliinisesti tärkeiden rakenteiden osoittamisessa on vähintään yhtä hyvä ja sen potilaalle aiheuttama sädeannos pienempi kuin nykyisen korva-spiraali-TT:n. Tämä tekee menetelmästä spiraali-TT:aa potilasturvallisemman vaihtoehdon erityisesti, jos potilaan tilanne vaatii seurantaa ja useampia kuvauksia, ja jos halutaan kuvata rajoitettuja alueita uni- tai bilateraalisesti.

Shortcomings of discontinuous-pressure finite element methods on a class of transient problems

Past studies that have compared LBB stable discontinuous- and continuous-pressure finite element formulations on a variety of problems have concluded that both methods yield Solutions of comparable accuracy, and that the choice of interpolation is dictated by which of the two is more efficient. In this work, we show that using discontinuous-pressure interpolations can yield inaccurate solutions at large times on a class of transient problems, while the continuous-pressure formulation yields solutions that are in good agreement with the analytical Solution.

The effect of closed boundary conditions on a stationary dynamo

One of two boundary conditions generally assumed in solutions of the dynamo equation is related to the disappearance of the azimuthal field at the boundary. Parker (1984) points out that for the realization of this condition the field must escape freely through the surface. Escape requires that the field be detached from the gas in which it is embedded. In the case of the sun, this can be accomplished only through reconnection in the tenuous gas above the visible surface. Parker concludes that the observed magnetic activity on the solar surface permits at most three percent of the emerging flux to escape. He arrives at the conclusion that, instead of B(phi) = 0, the partial derivative of B(phi) to r is equal to zero. The present investigation is concerned with the effect of changing the boundary condition according to Parker's conclusion. Implications for the solar convection zone are discussed.

Recent progress on synthesis, multi-scale structure, and properties of Y-Si-O oxides

Yttrium silicates (Y-Si-O oxides), including Y2Si2O7, Y2SiO5, and Y4·67(SiO4)3O apatite, have attracted wide attentions from material scientists and engineers, because of their extensive polymorphisms and important roles as grain boundary phases in improving the high-temperature mechanical/thermal properties of Si3N4and SiC ceramics. Recent interest in these materials has been renewed by their potential applications as high-temperature structural ceramics, oxidation protective coatings, and environmental barrier coatings (EBCs). The salient properties of Y-Si-O oxides are strongly related to their unique chemical bonds and microstructure features. An in-depth understanding on the synthesis - multi-scale structure-property relationships of the Y-Si-O oxides will shine a light on their performance and potential applications. In this review, recent progress of the synthesis, multi-scale structures, and properties of the Y-Si-O oxides are summarised. First, various methods for the synthesis of Y-Si-O ceramics in the forms of powders, bulks, and thin films/coatings are reviewed. Then, the crystal structures, chemical bonds, and atomic microstructures of the polymorphs in the Y-Si-O system are summarised. The third section focuses on the properties of Y-Si-O oxides, involving the mechanical, thermal, dielectric, and tribological properties, their environmental stability, and their structure-property relationships. The outlook for potential applications of Y-Si-O oxides is also highlighted.

A geometric approach for determining inner and exterior boundaries of workspaces of planar manipulators

In this paper a method to determine the internal and external boundaries of planar workspaces, represented with an ordered set of points, is presented. The sequence of points are grouped and can be interpreted to form a sequence of curves. Three successive curves are used for determining the instantaneous center of rotation for the second one of them. The two extremal points on the curve with respect to the instantaneous center are recognized as singular points. The chronological ordering of these singular points is used to generate the two envelope curves, which are potentially intersecting. Methods have been presented in the paper for the determination of the workspace boundary from the envelope curves. Strategies to deal with the manipulators with joint limits and various degenerate situations have also been discussed. The computational steps being completely geometric, the method does not require the knowledge about the manipulator's kinematics. Hence, it can be used for the workspace of arbitrary planar manipulators. A number of illustrative examples demonstrate the efficacy of the proposed method.

Lowering grain boundary resistance of BaZr0.8Y0.2O3−δ with LiNO3 sintering-aid improves proton conductivity for fuel cell operation

A novel sintering additive based on LiNO3 was used to overcome the drawbacks of poor sinterability and low grain boundary conductivity in BaZr0.8Y0.2O3-δ (BZY20) protonic conductors. The Li-additive totally evaporated during the sintering process at 1600°C for 6 h, which led to highly dense BZY20 pellets (96.5% of the theoretical value). The proton conductivity values of BZY20 with Li sintering-aid were significantly larger than the values reported for BZY sintered with other metal oxides, due to the fast proton transport in the "clean" grain boundaries and grain interior. The total conductivity of BZY20-Li in wet Ar was 4.45 × 10-3 S cm-1 at 600°C. Based on the improved sinterability, anode-supported fuel cells with 25 μm-thick BZY20-Li electrolyte membranes were fabricated by a co-firing technique. The peak power density obtained at 700°C for a BZY-Ni/BZY20-Li/La0.6Sr0.4Co0.2Fe 0.8O3-δ (LSCF)-BZY cell was 53 mW cm-2, which is significantly larger than the values reported for fuel cells using electrolytes made of BZY sintered with the addition of ZnO and CuO, confirming the advantage of using Li as a sintering aid.

Boundary-layer effects on internal flow choking in dual-thrust solid rocket motors

Theoretical studies have been carried out to examine internal flow choking in the inert simulators of a dual-thrust motor. Using a two-dimensional k-omega turbulence model, detailed parametric studies have been carried out to examine aerodynamic choking and the existence of a fluid throat at the transition region during the startup transient of dual-thrust motors. This code solves standard k-omega turbulence equations with shear flow corrections using a coupled second-order-implicit unsteady formulation. In the numerical study, a fully implicit finite volume scheme of the compressible, Reynolds-averaged, Navier-Stokes equations is employed. It was observed that, at the subsonic inflow conditions, there is a possibility of the occurrence of internal flow choking in dual-thrust motors due to the formation of a fluid throat at the beginning of the transition region induced by area blockage caused by boundary-layer-displacement thickness. It has been observed that a 55% increase in the upstream port area of the dual-thrust motor contributes to a 25% reduction in blockage factor at the transition region, which could negate the internal How choking and supplement with an early choking of the dual-thrust motor nozzle. If the height of the upstream port relative to the motor length is too small, the developing boundary layers from either side of the port can interact, leading to a choked,flow. On the other hand, if the developing boundary layers are far enough apart, then choking does not occur. The blockage factor is greater in magnitude for the choked case than for the unchoked case. More tangible explanations are presented in this paper for the boundary-layer blockage and the internal flow choking in dual-thrust motors, which hitherto has been unexplored.

Energy identities in water wave theory for free-surface boundary condition with higher-order derivatives

A modified form of Green's integral theorem is employed to derive the energy identity in any water wave diffraction problem in a single-layer fluid for free-surface boundary condition with higher-order derivatives. For a two-layer fluid with free-surface boundary condition involving higher-order derivatives, two forms of energy identities involving transmission and reflection coefficients for any wave diffraction problem are also derived here by the same method. Based on this modified Green's theorem, hydrodynamic relations such as the energy-conservation principle and modified Haskind–Hanaoka relation are derived for radiation and diffraction problems in a single as well as two-layer fluid.