906 research outputs found
Resonant Raman of OH/OD vibrations and photoluminescence studies in LiTaO3 thin film
Resonant Raman spectra (RRS) of O-H and O-D vibration and libration modes,
their combinations and higher harmonics have been observed in LiTaO3
polycrystalline thin films. RRS peaks are superimposed on photoluminescence
(PL) spectrum. Monochromatic light from a xenon lamp is used as excitation
source. PL spectrum shows two broad peaks, first near the band gap in UV
(4.4-4.8eV) and another in the sub band gap region (< 4.0 eV). Band gap PL
along with RRS peaks are reported for the first time. Photoluminescence
excitation spectrum (PLE) shows a peak at 4.8 eV. Peak positions and full width
at half maximum (FWHM) of RRS peaks depend upon the excitation energy.
Dispersions of the fundamental and the third harmonic of the stretching mode of
O-H with excitation energy are about 800 cm-1/eV and 2000 cm-1/eV respectively.
This dispersion is much higher than reported in any other material.Comment: 20 page
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Erratum: Consortium biology in immunology: The perspective from the Immunological Genome Project
Protein Content and Oil Composition of Almond from Moroccan Seedlings: Genetic Diversity, Oil Quality and Geographical Origin
The protein and oil content and the fatty acid profile of the kernels of selected almond genotypes from four different Moroccan regions were determined in order to evaluate the kernel quality of the plant material of these different regions. The ranges of oil content (48.7–64.5 % of kernel DW), oleic (61.8–80.2 % of total oil), linoleic (11.4–27.0 %), palmitic (5.6–7.7 %), stearic (1.3–3.1 %), and palmitoleic (0.4–0.9 %) acid percentages agreed with previous results of other almond genotypes, but the protein content (14.1–35.1 % of kernel DW) showed that some genotypes had higher values than any previously recorded in almond. Some genotypes from mountainous regions showed kernels with very high oil content as well as high and consistent oleic and linoleic ratio, establishing a possible differentiation according to the geographical origin. These differences may allow establishing a geographical denomination for almond products. In terms of genetic diversity, oleic and linoleic acids were confirmed to be the most variable components of almond oil chemical composition among genotypes. Additionally, the genotypes with extreme favorable values, such as high protein content, could be incorporated into an almond breeding program aiming at an increase in kernel quality.Peer ReviewedPrunus amygdalusProtein contentOil contentFatty acidsQualityGenetic resourcesBreedingPublishe
Transverse Electronic Transport through DNA Nucleotides with Functionalized Graphene Electrodes
Graphene nanogaps and nanopores show potential for the purpose of electrical
DNA sequencing, in particular because single-base resolution appears to be
readily achievable. Here, we evaluated from first principles the advantages of
a nanogap setup with functionalized graphene edges. To this end, we employed
density functional theory and the non-equilibrium Green's function method to
investigate the transverse conductance properties of the four nucleotides
occurring in DNA when located between the opposing functionalized graphene
electrodes. In particular, we determined the electrical tunneling current
variation as a function of the applied bias and the associated differential
conductance at a voltage which appears suitable to distinguish between the four
nucleotides. Intriguingly, we observe for one of the nucleotides a negative
differential resistance effect.Comment: 19 pages, 7 figure
PIK3CA dependence and sensitivity to therapeutic targeting in urothelial carcinoma
Background
Many urothelial carcinomas (UC) contain activating PIK3CA mutations. In telomerase-immortalized normal urothelial cells (TERT-NHUC), ectopic expression of mutant PIK3CA induces PI3K pathway activation, cell proliferation and cell migration. However, it is not clear whether advanced UC tumors are PIK3CA-dependent and whether PI3K pathway inhibition is a good therapeutic option in such cases.
Methods
We used retrovirus-mediated delivery of shRNA to knock down mutant PIK3CA in UC cell lines and assessed effects on pathway activation, cell proliferation, migration and tumorigenicity. The effect of the class I PI3K inhibitor GDC-0941 was assessed in a panel of UC cell lines with a range of known molecular alterations in the PI3K pathway.
Results
Specific knockdown of PIK3CA inhibited proliferation, migration, anchorage-independent growth and in vivo tumor growth of cells with PIK3CA mutations. Sensitivity to GDC-0941 was dependent on hotspot PIK3CA mutation status. Cells with rare PIK3CA mutations and co-occurring TSC1 or PTEN mutations were less sensitive. Furthermore, downstream PI3K pathway alterations in TSC1 or PTEN or co-occurring AKT1 and RAS gene mutations were associated with GDC-0941 resistance.
Conclusions
Mutant PIK3CA is a potent oncogenic driver in many UC cell lines and may represent a valuable therapeutic target in advanced bladder cancer
Tissue Microenvironments Define and Get Reinforced by Macrophage Phenotypes in Homeostasis or during Inflammation, Repair and Fibrosis
Current macrophage phenotype classifications are based on distinct in vitro culture conditions that do not adequately mirror complex tissue environments. In vivo monocyte progenitors populate all tissues for immune surveillance which supports the maintenance of homeostasis as well as regaining homeostasis after injury. Here we propose to classify macrophage phenotypes according to prototypical tissue environments, e.g. as they occur during homeostasis as well as during the different phases of (dermal) wound healing. In tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce proinflammatory macrophages by Toll-like receptors or inflammasomes. Such classically activated macrophages contribute to further tissue inflammation and damage. Apoptotic cells and antiinflammatory cytokines dominate in postinflammatory tissues which induce macrophages to produce more antiinflammatory mediators. Similarly, tumor-associated macrophages also confer immunosuppression in tumor stroma. Insufficient parenchymal healing despite abundant growth factors pushes macrophages to gain a profibrotic phenotype and promote fibrocyte recruitment which both enforce tissue scarring. Ischemic scars are largely devoid of cytokines and growth factors so that fibrolytic macrophages that predominantly secrete proteases digest the excess extracellular matrix. Together, macrophages stabilize their surrounding tissue microenvironments by adapting different phenotypes as feed-forward mechanisms to maintain tissue homeostasis or regain it following injury. Furthermore, macrophage heterogeneity in healthy or injured tissues mirrors spatial and temporal differences in microenvironments during the various stages of tissue injury and repair. Copyright (C) 2012 S. Karger AG, Base
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Illustrating the effect of viscoelastic additives on cavitation and turbulence with X-ray imaging
The effect of viscoelastic additives on the topology and dynamics of the two-phase flow arising within an axisymmetric orifice with a flow path constriction along its main axis has been investigated employing high-flux synchrotron radiation. X-ray Phase Contrast Imaging (XPCI) has been conducted to visualise the cavitating flow of different types of diesel fuel within the orifice. An additised blend containing Quaternary Ammonium Salt (QAS) additives with a concentration of 500 ppm has been comparatively examined against a pure (base) diesel compound. A high-flux, 12 keV X-ray beam has been utilised to obtain time resolved radiographs depicting the vapour extent within the orifice from two views (side and top) with reference to its main axis. Different test cases have been examined for both fuel types and for a range of flow conditions characterised by Reynolds number of 35500 and cavitation numbers (CN) lying in the range 3.0–7.7. It has been established that the behaviour of viscoelastic micelles in the regions of shear flow is not consistent depending on the cavitation regimes encountered. Namely, viscoelastic effects enhance vortical (string) cavitation, whereas hinder cloud cavitation. Furthermore, the use of additised fuel has been demonstrated to suppress the level of turbulence within the orifice
A Novel Technique of Uterine Manipulation in Laparoscopic Pelvic Oncosurgical Procedures: “The Uterine Hitch Technique”
Aim. To describe a new technique of uterine manipulation in laparoscopic management of pelvic cancers. Material and Methods. We used a novel uterine hitch technique in 23 patients from May 2008 to October 2008. These patients underwent pelvic oncologic surgery including laparoscopic radical hysterectomy (n = 7), laparoscopic anterior resection (n = 4), laparoscopic abdominoperineal resection (n = 3), laparoscopic posterior exenteration (n = 4), or laparoscopic anterior exenteration (n = 5). The uterus was hitched to the anterior abdominal.wall by either a single suture in the fundus or by sutures through the round ligaments. Results. The uterine hitch technique was successfully accomplished in all procedures. It was performed in less than 5 minutes in all cases. It obviated the need for vaginal manipulation. An extra port for retraction could be avoided. There were no intraoperative complications. Conclusion. A practical, cheap and reproducible method for uterine manipulation, during pelvic oncologic surgery is described. It improves the stability of the uterus and also obviates the need for keeping an additional assistant for vaginal manipulation in any of the procedures
Glucocorticoid receptor in astrocytes regulates midbrain dopamine neurodegeneration through connexin hemichannel activity
The precise contribution of astrocytes in neuroinflammatory process occurring in Parkinson's disease (PD) is not well characterized. In this study, using GR(Cx30CreERT2) mice that are conditionally inactivated for glucocorticoid receptor (GR) in astrocytes, we have examined the actions of astrocytic GR during dopamine neuron (DN) degeneration triggered by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The results show significantly augmented DN loss in GR(Cx30CreERT2) mutant mice in substantia nigra (SN) compared to controls. Hypertrophy of microglia but not of astrocytes was greatly enhanced in SN of these astrocytic GR mutants intoxicated with MPTP, indicating heightened microglial reactivity compared to similarly-treated control mice. In the SN of GR astrocyte mutants, specific inflammation-associated transcripts ICAM-1, TNF-alpha and Il-1 beta as well as TNF-alpha protein levels were significantly elevated after MPTP neurotoxicity compared to controls. Interestingly, this paralleled increased connexin hemichannel activity and elevated intracellular calcium levels in astrocytes examined in acute midbrain slices from control and mutant mice treated with MPP+. The increased connexin-43 hemichannel activity was found in vivo in MPTP-intoxicated mice. Importantly, treatment of MPTP-injected GR(Cx30CreERT2) mutant mice with TAT-Gap19 peptide, a specific connexin-43 hemichannel blocker, reverted both DN loss and microglial activation; in wild-type mice there was partial but significant survival effect. In the SN of postmortem PD patients, a significant decrease in the number of astrocytes expressing nuclear GR was observed, suggesting the participation of astrocytic GR deregulation of inflammatory process in PD. Overall, these data provide mechanistic insights into GR-modulated processes in vivo, specifically in astrocytes, that contribute to a pro-inflammatory state and dopamine neurodegeneration in PD pathology
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