8,483 research outputs found
Pattern formation during the evaporation of a colloidal nanoliter drop: a numerical and experimental study
An efficient way to precisely pattern particles on solid surfaces is to
dispense and evaporate colloidal drops, as for bioassays. The dried deposits
often exhibit complex structures exemplified by the coffee ring pattern, where
most particles have accumulated at the periphery of the deposit. In this work,
the formation of deposits during the drying of nanoliter colloidal drops on a
flat substrate is investigated numerically and experimentally. A finite-element
numerical model is developed that solves the Navier-Stokes, heat and mass
transport equations in a Lagrangian framework. The diffusion of vapor in the
atmosphere is solved numerically, providing an exact boundary condition for the
evaporative flux at the droplet-air interface. Laplace stresses and thermal
Marangoni stresses are accounted for. The particle concentration is tracked by
solving a continuum advection-diffusion equation. Wetting line motion and the
interaction of the free surface of the drop with the growing deposit are
modeled based on criteria on wetting angles. Numerical results for evaporation
times and flow field are in very good agreement with published experimental and
theoretical results. We also performed transient visualization experiments of
water and isopropanol drops loaded with polystyrene microsphere evaporating on
respectively glass and polydimethylsiloxane substrates. Measured evaporation
times, deposit shape and sizes, and flow fields are in very good agreement with
the numerical results. Different flow patterns caused by the competition of
Marangoni loops and radial flow are shown to determine the deposit shape to be
either a ring-like pattern or a homogeneous bump
Improvement in Grinding and Classification Circuit by the use of Hydrocone at Rakha Concentrator
With increase in demand of metals, depleting ore reserves, falling ore grades and manyfold increase in operational cost, many of the mineral industries are now facing the prospect of closing their operations. However, efforts are being made at every place to reduce the cost of production through innovations and improvement tech-nology
Irradiation of benzene molecules by ion-induced and light-induced intense fields
Benzene, with its sea of delocalized -electrons in the valence orbitals,
is identified as an example of a class of molecules that enable establishment
of the correspondence between intense ion-induced and laser-light-induced
fields in experiments that probe ionization dynamics in temporal regimes
spanning the attosecond and picosecond ranges.Comment: 4 ps figure
Targeting Btk/Etk of prostate cancer cells by a novel dual inhibitor.
Btk and Etk/BMX are Tec-family non-receptor tyrosine kinases. Btk has previously been reported to be expressed primarily in B cells and has an important role in immune responses and B-cell malignancies. Etk has been shown previously to provide a strong survival and metastasis signal in human prostate cancer cells, and to confer androgen independence and drug resistance. While the role of Etk in prostate carcinogenesis is well established, the functions of Btk in prostate cancer have never been investigated, likely due to the perception that Btk is a hematopoietic, but not epithelial, kinase. Herein, we found that Btk is overexpressed in prostate cancer tissues and prostate cancer cells. The level of Btk in prostate cancer tissues correlates with cancer grades. Knockdown of Btk expression selectively inhibits the growth of prostate cancer cells, but not that of the normal prostate epithelial cells, which express very little Btk. Dual inhibition of Btk and Etk has an additive inhibitory effect on prostate cancer cell growth. To explore Btk and Etk as targets for prostate cancer, we developed a small molecule dual inhibitor of Btk and Etk, CTN06. Treatment of PC3 and other prostate cancer cells, but not immortalized prostate epithelial cells with CTN06 resulted in effective cell killing, accompanied by the attenuation of Btk/Etk signals. The killing effect of CTN06 is more potent than that of commonly used inhibitors against Src, Raf/VEGFR and EGFR. CTN06 induces apoptosis as well as autophagy in human prostate cancer cells, and is a chemo-sensitizer for docetaxel (DTX), a standard of care for metastatic prostate cancer patients. CTN06 also impeded the migration of human prostate cancer cells based on a 'wound healing' assay. The anti-cancer effect of CTN06 was further validated in vivo in a PC3 xenograft mouse model
Electron attachment to valence-excited CO
The possibility of electron attachment to the valence state of CO
is examined using an {\it ab initio} bound-state multireference configuration
interaction approach. The resulting resonance has symmetry;
the higher vibrational levels of this resonance state coincide with, or are
nearly coincident with, levels of the parent state. Collisional
relaxation to the lowest vibrational levels in hot plasma situations might
yield the possibility of a long-lived CO state.Comment: Revtex file + postscript file for one figur
Xâray emission from the outer planets: Albedo for scattering and fluorescence of solar X rays
Soft Xâray emission has been observed from the lowâlatitude "disk" of both Jupiter and Saturn as well as from the auroral regions of these planets. The disk emission as observed by ROSAT, the Chandra XâRay Observatory, and XMMâNewton appears to be uniformly distributed across the disk and to be correlated with solar activity. These characteristics suggest that the disk X rays are produced by (1) the elastic scattering of solar X rays by atmospheric neutrals and (2) the absorption of solar X rays in the carbon Kâshell followed by fluorescent emission. The carbon atoms are found in methane molecules located below the homopause. In this paper we present the results of calculations of the scattering albedo for soft X rays. We also show the calculated Xâray intensity for a range of atmospheric abundances for Jupiter and Saturn and for a number of solar irradiance spectra. The model calculations are compared with recent Xâray observations of Jupiter and Saturn. We conclude that the emission of soft X rays from the disks of Jupiter and Saturn can be largely explained by the scattering and fluorescence of solar soft X rays. We suggest that measured Xâray intensities from the disk regions of Jupiter and Saturn can be used to constrain both the absolute intensity and the spectrum of solar X rays
XMM-Newton observations of X-ray emission from Jupiter
We present the results of two XMM-Newton observations of Jupiter carried out
in 2003 for 100 and 250 ks (or 3 and 7 planet rotations) respectively. X-ray
images from the EPIC CCD cameras show prominent emission from the auroral
regions in the 0.2 - 2.0 keV band: the spectra are well modelled by a
combination of emission lines, including most prominently those of highly
ionised oxygen (OVII and OVIII). In addition, and for the first time,
XMM-Newton reveals the presence in both aurorae of a higher energy component (3
- 7 keV) which is well described by an electron bremsstrahlung spectrum. This
component is found to be variable in flux and spectral shape during the Nov.
2003 observation, which corresponded to an extended period of intense solar
activity. Emission from the equatorial regions of Jupiter's disk is also
observed, with a spectrum consistent with that of solar X-rays scattered in the
planet's upper atmosphere. Jupiter's X-rays are spectrally resolved with the
RGS which clearly separates the prominent OVII contribution of the aurorae from
the OVIII, FeXVII and MgXI lines, originating in the low-latitude disk regions
of the planet.Comment: 6 pages, 11 figures, Proceedings of the Symposium 'The X-ray Universe
2005', San Lorenzo de El Escorial, Spain, 26-30 September 2005. In pres
A study of Jupiter's aurorae with XMM-Newton
We present a detailed analysis of Jupiter's X-ray (0.2-10 keV) auroral
emissions as observed by XMM-Newton in Nov. 2003 and compare it with that of an
Apr. 2003 observation. We discover the existence of an electron bremsstrahlung
component in the aurorae, which accounts for essentially all the X-ray flux
above 2 keV: its presence had been predicted but never detected for lack of
sensitivity of previous X-ray missions. This bremsstrahlung component varied
significantly in strength and spectral shape over the 3.5 days covered by the
Nov. 2003 observation, displaying substantial hardening of the spectrum with
increasing flux. This variability may be linked to the strong solar activity
taking place at the time, and may be induced by changes in the acceleration
mechanisms inside Jupiter's magnetosphere. As in Apr. 2003, the auroral spectra
below 2 keV are best fitted by a superposition of line emission most likely
originating from ion charge exchange, with OVII playing the dominant role. We
still cannot resolve conclusively the ion species responsible for the lowest
energy lines (around 0.3 keV), so the question of the origin of the ions
(magnetospheric or solar wind) is still open. It is conceivable that both
scenarios play a role in what is certainly a very complex planetary structure.
High resolution spectra of the whole planet obtained with the XMM-Newton RGS in
the range 0.5-1 keV clearly separate emission lines (mostly of Fe) originating
at low latitudes on Jupiter from the auroral lines due to O. These are shown to
possess very broad wings which imply velocities of ~5000 km/s. Such speeds are
consistent with the energies at which precipitating and charge exchanging O
ions are expected to be accelerated in Jupiter's magnetosphere. Overall we find
good agreement between our measurements and the predictions of recent models.Comment: 16 pages, 17 figures, to be published in 'Astronomy and Astrophysics
Design optimization of pixel sensors using device simulations for the phase-II CMS tracker upgrade
In order to address the problems caused by the harsh radiation environment during the high luminosity phase of the LHC (HL-LHC), all silicon tracking detectors (pixels and strips) in the CMS experiment will undergo an upgrade. And so to develop radiation hard pixel sensors, simulations have been performed using the 2D TCAD device simulator, SILVACO, to obtain design parameters. The effect of various design parameters like pixel size, pixel depth, implant width, metal overhang, p-stop concentration, p-stop depth and bulk doping density on the leakage current and critical electric field are studied for both non-irradiated as well as irradiated pixel sensors. These 2D simulation results of planar pixels are useful for providing insight into the behaviour of non-irradiated and irradiated silicon pixel sensors and further work on 3D simulation is underway. © 2015 Elsevier B.V
Current Treatment Approaches to HCC with a Special Consideration to Transplantation
Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. The mainstay of treatment of HCC has been both resectional and transplantation surgery. It is well known that, in selected, optimized patients, hepatectomy for HCC may be an option, even in patients with underlying cirrhosis. Resectable patients with early HCC and underlying liver disease are however increasingly being considered for transplantation because of potential for better disease-free survival and resolution of underlying liver disease, although this approach is limited by the availability of donor livers, especially in resectable patients. Outcomes following liver transplantation improved dramatically for patients with HCC following the implementation of the Milan criteria in the late 1990s. Ever since, the rather restrictive nature of the Milan criteria has been challenged with good outcomes. There has also been an increase in the donor pool with marginal donors including organs retrieved following cardiac death being used. Even so, patients still continue to die while waiting for a liver transplant. In order to reduce this attrition, bridging techniques and methods for downstaging disease have evolved. Additionally new techniques for organ preservation have increased the prospect of this potentially curative procedure being available for a greater number of patients
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