43 research outputs found
Location-Specific Epigenetic Regulation of the Metallothionein 3 Gene in Esophageal Adenocarcinomas
Metallothionein 3 (MT3) maintains intracellular metal homeostasis and protects against reactive oxygen species (ROS)-induced DNA damage. In this study, we investigated the epigenetic alterations and gene expression of the MT3 gene in esophageal adenocarcinomas (EACs).Using quantitative bisulfite pyrosequencing, we detected unique DNA methylation profiles in the MT3 promoter region. The CpG nucleotides from -372 to -306 from the transcription start site (TSS) were highly methylated in tumor (n = 64) and normal samples (n = 51), whereas CpG nucleotides closest to the TSS (-4 and +3) remained unmethylated in all normal and most tumor samples. Conversely, CpG nucleotides in two regions (from -139 to -49 and +296 to +344) were significantly hypermethylated in EACs as compared to normal samples [FDR<0.001, -log10(FDR)>3.0]. The DNA methylation levels from -127 to -8 CpG sites showed the strongest correlation with MT3 gene expression (r = -0.4, P<0.0001). Moreover, the DNA hypermethylation from -127 to -8 CpG sites significantly correlated with advanced tumor stages and lymph node metastasis (P = 0.005 and P = 0.0313, respectively). The ChIP analysis demonstrated a more repressive histone modification (H3K9me2) and less active histone modifications (H3K4me2, H3K9ace) in OE33 cells than in FLO-1 cells; concordant with the presence of higher DNA methylation levels and silencing of MT3 expression in OE33 as compared to FLO-1 cells. Treatment of OE33 cells with 5-Aza-deoxycitidine restored MT3 expression with demethylation of its promoter region and reversal of the histone modifications towards active histone marks.In summary, EACs are characterized by frequent epigenetic silencing of MT3. The choice of specific regions in the CpG island is a critical step in determining the functional role and prognostic value of DNA methylation in cancer cells
An upper limit to the photon fraction in cosmic rays above 10^19 eV from the Pierre Auger Observatory
An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies above 10^19 eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory. This is the first such limit on photons obtained by observing the fluorescence light profile of air showers. This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays. Additional data recorded with the Auger surface detectors for a subset of the event sample, support the conclusion that a photon origin of the observed events is not favoured
Electrospun Ultrafine Fiber Composites Containing Fumed Silica: From Solution Rheology to Materials with Tunable Wetting
Fumed silica (FS)
particles with hydrophobic (R805) or hydrophilic
(A150) surface functionalities are incorporated in polyacrylonitrile
(PAN) fibers by electrospinning to produce mats with controlled wettability.
Rheological measurements are conducted to elucidate the particle–polymer
interactions and characterize the system while microscopic and analytic
tools are used to examine FS location within both fibers and films
to aid in the fundamental understanding of wetting behavior. Unlike
traditional polymers, we find these systems to be gel-like, yet electrospinnable;
the fumed silica networks break down into smaller aggregates during
the electrospinning process and disperse both within and on the surface
of the fibers. Composite nanofiber mats containing R805 FS exhibit
an apparent contact angle over 130° and remain hydrophobic over
30 min, while similar mats with A150 display rapid surface-wetting
with a static contact angle of ∼30°. Wicking experiments
reveal that the water absorption properties can be further manipulated,
with R805 FS-impregnated mats taking up only 8% water relative to
mat weight in 15 min. In contrast, PAN fibers containing A150 FS absorb
425% of water in the same period, even more than the pure PAN fiber
(371%). The vastly different responses to water demonstrate the versatility
of FS in surface modification, especially for submicron fibrous mats.
The role of fumed silica in controlling wettability is discussed in
terms of their surface functionality, placement on nanofibers and
induced surface roughness
Alginate–Polyethylene Oxide Blend Nanofibers and the Role of the Carrier Polymer in Electrospinning
We
present here a systematic investigation to understand why aqueous
sodium alginate can only be electrospun into fibers through a blend
with another polymer; specifically, polyethylene oxide (PEO). We seek
to examine and understand the role of PEO as the “carrier polymer”.
The addition of PEO favorably reduces electrical conductivity and
surface tension of the alginate solution, aiding in fiber formation.
While PEO has the ability to coordinate through its ether group (−COC−)
with metal cation like the sodium cation of sodium alginate, we demonstrate
in this study using PEO as well as polyvinyl alcohol (PVA) that coordination
may have little effect on electrospinnability. More importantly, we
show that PEO as carrier polymer provides molecular entanglement that
is required for electrospinning. Since the selected carrier polymer
provides the necessary entanglement, this carrier polymer must be
electrospinnable, entangled and of a high molecular weight (more than
600 kDa for PEO). On the basis of these requirements, we stipulate
that the PEO–PEO interaction of the high molecular-weight entangled
PEO is key to “carrying” the alginate from solution
to fibers during electrospinning. Further, using the resulting understanding
of the role of PEO, we were able to increase the alginate concentration
by employing a higher molecular-weight PEO: up to 70 wt % alginate
using 2000 kDa PEO and, with, the addition of Triton X-100 surfactant,
up to 85 wt % alginate, higher than previously reported
Photo-activated ionic gelation of alginate hydrogel: real-time rheological monitoring of the two-step crosslinking mechanism
Käytännön kosteikkosuunnittelu
Maatalouden vesiensuojelua edistetään monin tavoin. Ravinteita ja eroosioainesta sisältäviä valumavesiä pyritään puhdistamaan erilaisissa kosteikoissa. Tämä opas on kirjoitettu avuksi pienimuotoisten kosteikkojen perustamiseen. Oppaassa esitetään käytännönläheisesti kosteikon toteuttamisen eri vaiheet paikan valinnasta suunnitteluun ja rakentamiseen. Vuonna 2010 julkaistun painoksen tiedot on saatettu ajantasalle.
Julkaisu on toteutettu osana Tehoa maatalouden vesiensuojeluun (TEHO) -hanketta ja päivitetty TEHO Plus -hankkeen toimesta. Oppaan toivotaan lisäävän kiinnostusta kosteikkojen suunnitteluun ja edelleen niiden rakentamiseen