692 research outputs found
The Feedwater Control System and Steam Dump Control System Responses During Large-Load Reduction Transient for Maanshan PWR Plant
AbstractIn this study, the development of TRACE (TRAC/RELAP Advanced Computational Engine) models for Maanshan nuclear power plant (NPP) important control systems, such as feedwater control system and steam dump control system, are performed in using SNAP (Symbolic Nuclear Analysis Program) / TRACE. The large-load reduction transient analysis of the Maanshan NPP control system TRACE models are also performed and the responses of the control systems of TRACE models compare with Maanshan NPP startup tests data to verify their accuracy. Analysis results of TRACE indicate that the responses of the Maanshan NPP control system TRACE models are consistent with the plant data for large-load reduction transient
Ring Keratitis Associated With Topical Abuse of a Dilute Anesthetic After Refractive Surgery
Anesthetic toxic keratitis is rare and presents as a ring keratitis, which is often misdiagnosed as Acanthamoeba keratitis. Here, we report an unusual case of toxic keratitis caused by topical abuse of a dilute anesthetic. A 26-year-old woman presented with bilateral corneal edema, ring infiltrates, pigmented keratic precipitate, Descemet's membrane folding, and strong anterior chamber reactions 2 weeks after laser subepithelial keratomileusis surgery. Tracing back her medical history, topical dilute 0.1% proparacaine was prescribed and frequently used for 1 month. Toxic keratitis was suspected. After discontinuation of the topical anesthetic and initiation of treatment with topical 20% autologous serum, complete corneal epithelialization was achieved within 1 week. Corneal infiltrates and anterior chamber reaction gradually subsided. Vision improved from finger counting to 20/20 in the right eye and 20/25 in the left eye, but confocal microscopy showed decreased corneal endothelial cells. Topical abuse of a dilute topical anesthetic can cause severe toxic keratitis and endothelial cell loss. The physician must be aware of the signs of topical anesthetic abuse and should not prescribe even a dilute anesthetic for long-term use. Autologous serum can help in the recovery of toxic keratitis
Polythiophenes comprising conjugated pendantstoward long-term air-stable inverted polymer solar cellswith high open circuit voltages
A series of polythiophenes (PTs) functionalized with bulky conjugated side chains comprising tert-butylsubstituted carbazole (tCz) as an electron donor pendant and bisbenzothiazolylvinyl (DBT) as anelectron acceptor pendant were synthesized via Stille copolymerization for polymer solar cell (PSC)applications. We use the descriptors PTtCz, PT(tCz)0.9(DBT)0.1, PT(tCz)0.64(DBT)0.36, PT(tCz)0.45(DBT)0.55,and PTDBT to identify each of these conjugated polymers, with the names denoting the compositionsof the bulky pendants. The tunable energy levels of the PTs were accomplished by incorporating bothtCz as a donor pendant and DBT as an acceptor pendant, while retaining the low-lying HOMO levels( 5.26 to 5.39 eV). Furthermore, lower bandgaps were observed for the DBT-derived PTs because ofstronger donor–p–acceptor characteristics and more efficient intramolecular charge transfer.Conventional PSCs were fabricated by spin-coating the blend of each PT and the fullerene derivative(PC71BM). The conventional PSC devices exhibited high open circuit voltages (Voc) of around 0.79–0.91 V. The power conversion efficiency (PCE) of the PSCs based on PTtCz : PC71BM (w/w ¼ 1 : 2.5)reached 2.48% with a Voc of 0.91 V, short circuit current (Jsc) of 6.58 (mA cm 2) and fill factor (FF) of41% under the illumination of AM1.5, 100 mW cm 2. Furthermore, a PTtCz/PC71BM-based inverted PSCwith ZnOx and MoO3 as an electron extraction layer and a hole extraction layer respectively was capableof retaining ca. 80% of its original efficiency after storage under ambient conditions (withoutencapsulation) for 1032 h, according to the ISOS-D-1 shelf protocol. The highly durable inverted PSCaccompanied by a large Voc value was achieved for the PT-type polymers
Autologous serum therapy in recalcitrant laser-assisted in situ keratomileusis-induced neurotrophic epitheliopathy
AbstractBackground/PurposeTo evaluate the efficacy of autologous serum eye drops for patients with recalcitrant laser-assisted in situ keratomileusis (LASIK)-induced neurotrophic epitheliopathy (LINE) unresponsive to conventional treatment, and to determine the possible predisposing risk factors of these patients.MethodsWe enrolled 10 consecutive patients (20 eyes) undergoing femtosecond-assisted myopic LASIK surgery presenting with recalcitrant LINE for > 1 year. Another 340 patients (713 eyes) receiving femtosecond-assisted myopic LASIK without recalcitrant LINE were set as controls. Possible risk factors associated with recalcitrant LINE were investigated. Twenty percent autologous serum treatment was prescribed to 20 eyes. The efficacy of autologous serum was assessed with ocular surface conditions, tear function, and the change of best-corrected visual acuity.ResultsAge older than 30 years [odds ratio (OR) = 7.74; 95% confidence interval (CI), 1.74–34.50], flap thickness < 110 μm (OR = 3.47; 95% CI, 1.22–9.73), and a flap diameter < 8.5 mm (OR = 5.38; 95% CI, 1.95–14.85) pose higher risks in femtosecond laser-assisted myopic LASIK. All eyes (100%) achieved remission after autologous serum treatment. The visual acuity before treatment was 0.49 ± 0.41 in LogMAR, and the visual acuity after treatment was 0.14 ± 0.22 in LogMAR. Time to achieve remission was 8.26 ± 11.87 weeks. Mean relapse-free survival after discontinuing autologous serum was 47 weeks.ConclusionRisk factors of recalcitrant LINE in femtosecond laser-assisted myopic LASIK were identified as older age, a thinner flap (<110 μm), and a small flap diameter (<8.5 mm). Autologous serum eye drops can effectively improve corneal surface conditions and postoperative visual acuity
Ellagic Acid, the Active Compound of Phyllanthus urinaria, Exerts In Vivo Anti-Angiogenic Effect and Inhibits MMP-2 Activity
This study aimed to assess the potential anti-angiogenic mechanism of Phyllanthus urinaria (P. urinaria) and characterize the major compound in P. urinaria that exerts anti-angiogenic effect. The water extract of P. urinaria and Ellagic Acid were used to evaluate the anti-angiogenic effect in chorioallantoic membrane (CAM) in chicken embryo and human vascular endothelial cells (HUVECs). The matrix metalloproteinase-2 (MMP-2) activity was determined by gelatin zymography. The mRNA expressions of MMP-2, MMP-14 and tissue inhibitor of metalloproteinase-2 (TIMP-2) were analyzed by reverse transcription polymerase chain reaction (RT-PCR). Level of MMP-2 proteins in conditioned medium or cytosol was determined by western blot analysis. We confirmed that P. urinaria's in vivo anti-angiogenic effect was associated with a reduction in MMP-2 activity. Ellagic acid, one of the major polyphenolic components as identified in P. urinaria by high performance liquid chromatography mass spectrometry (HPLC/MS), exhibited the same anti-angiogenic effect in vivo. Both P. urinaria and Ellagic Acid inhibited MMP-2 activity in HUVECs with unchanged mRNA level. The mRNA expression levels of MMP-14 and TIMP-2 were not altered either. Results from comparing the change of MMP-2 protein levels in conditioned medium and cytosol of HUVECs after the P. urinaria or Ellagic Acid treatment revealed an inhibitory effect on the secretion of MMP-2 protein. This study concluded that Ellagic Acid is the active compound in P. urinaria to exhibit anti-angiogenic activity and to inhibit the secretion of MMP-2 protein from HUVECs
Cosmological evolution of supermassive black holes. I. mass function at 0<z<2
We present the mass function of supermassive black holes (SMBHs) over the
redshift range z=0-2, using the latest deep luminosity and mass functions of
field galaxies to constrain the masses of their spheroids, which we relate to
SMBH mass through the empirical correlation between SMBH and spheroid mass (the
M_bh-M_sph relation). In ddition to luminosity fading of the stellar content of
the spheroids, we carefully consider the variation of the bulge-to-total
luminosity ratio of the galaxy populations and the M_bh/M_sph ratio, which,
according to numerous recent studies, evolves rapidly with redshift. The SMBH
mass functions derived from the galaxy luminosity and mass functions show very
good agreement, both in shape and in normalization. The resultant SMBH mass
function and integrated mass density for the local epoch (z~0) match well those
derived independently by other studies. Consistent with other evidence for
cosmic downsizing, the upper end of the mass function remains roughly constant
since , while the space density of lower mass black holes undergoes
strong evolution. We carefully assess the impact of various sources of
uncertainties on our calculations. A companion paper uses the mass function
derived in this work to determine the radiative efficiency of black hole
accretion and constraints that can be imposed on the cosmological evolution of
black hole spin.Comment: To appear in ApJ, 10 pages, 11 figures and 1 tabl
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