1,561 research outputs found
Sparsity and cosparsity for audio declipping: a flexible non-convex approach
This work investigates the empirical performance of the sparse synthesis
versus sparse analysis regularization for the ill-posed inverse problem of
audio declipping. We develop a versatile non-convex heuristics which can be
readily used with both data models. Based on this algorithm, we report that, in
most cases, the two models perform almost similarly in terms of signal
enhancement. However, the analysis version is shown to be amenable for real
time audio processing, when certain analysis operators are considered. Both
versions outperform state-of-the-art methods in the field, especially for the
severely saturated signals
Downstream etching of silicon nitride using continuous-wave and pulsed remote plasma sources sustained in Ar/NF3/O-2 mixtures
Remote plasma sources (RPSs) are being investigated to produce fluxes of radicals for low damage material processing. In this computational investigation, the properties of a RPS etching system are discussed where an Ar/NF3/O2 gas mixture is flowed through an inductively coupled plasma source into a downstream chamber containing a silicon nitride coated wafer. The plasma is largely confined in the RPS due to the highly attaching NFx (x = 1–3) and an isolating showerhead although a weak ion-ion plasma maintained by [NO+] ≈ [F−] leaks into the downstream chamber. The etching of silicon nitride proceeds through iterative removal of Si and N subsites by isotropic thermal neutrals. When the fluxes to the wafer are rich in fluorine radicals, the etch rate is limited by the availability of NO molecules and N atoms which remove N subsites. As power deposition increases with continuous-wave excitation, the etch rate increases almost linearly with the increasing fluxes of NO and N atoms, as production of NO through endothermic reactions is aided by increasing gas temperature. Production of N atoms through electron impact dissociation of NO and NFx is aided by the increasing electron density. Similar trends occur when increasing the duty cycle during pulsed excitation. Addition of a plenum between the RPS and the downstream chamber aids in lateral diffusion of radicals before passing through the final showerhead and improves the uniformity of etching
Comparative efficacy of two poeciliid fish in indoor cement tanks against chikungunya vector Aedes aegypti in villages in Karnataka, India
<p>Abstract</p> <p>Background</p> <p>In 2006, severe outbreaks of <it>Aedes aegypti</it>-transmitted chikungunya occurred in villages in Karnataka, South India. We evaluated the effectiveness of combined information, education and communication (IEC) campaigns using two potential poeciliid larvivorous fish guppy (<it>Poecilia reticulata</it>) and mosquitofish (<it>Gambusia affinis</it>), in indoor cement tanks for <it>Aedes </it>larval control.</p> <p>Methods</p> <p>Trials were conducted in two villages (Domatmari and Srinivaspura) in Tumkur District from March to May 2006 for <it>Poecilia </it>and one village (Balmanda) in Kolar District from July to October 2006 for <it>Gambusia</it>. A survey on knowledge, attitude and practice (KAP) on chikungunya was initially conducted and IEC campaigns were performed before and after fish release in Domatmari (IEC alone, followed by IEC + <it>Poecilia</it>) and Balmanda (IEC + <it>Gambusia</it>). In Srinivaspura, IEC was not conducted. Larval surveys were conducted at the baseline followed by one-week and one-month post-intervention periods. The impact of fish on <it>Aedes </it>larvae and disease was assessed based on baseline and post-intervention observations.</p> <p>Results</p> <p>Only 18% of respondents knew of the role of mosquitoes in fever outbreaks, while almost all (<it>n </it>= 50 each) gained new knowledge from the IEC campaigns. In Domatmari, IEC alone was not effective (OR 0.54; <it>p </it>= 0.067). Indoor cement tanks were the most preferred <it>Ae. aegypti </it>breeding habitat (86.9%), and had a significant impact on <it>Aedes </it>breeding (Breteau Index) in all villages in the one-week period (<it>p </it>< 0.001). In the one-month period, the impact was most sustained in Domatmari (OR 1.58, <it>p </it>< 0.001) then Srinivaspura (OR 0.45, <it>p </it>= 0.063) and Balmanda (OR 0.51, <it>p </it>= 0.067). After fish introductions, chikungunya cases were reduced by 99.87% in Domatmari, 65.48% in Srinivaspura and 68.51% in Balmanda.</p> <p>Conclusions</p> <p><it>Poecilia </it>exhibited greater survival rates than <it>Gambusia </it>(86.04 <it>vs</it>.16.03%) in cement tanks. Neither IEC nor <it>Poecilia </it>alone was effective against <it>Aedes </it>(<it>p </it>> 0.05). We conclude that <it>Poecilia </it>+ IEC is an effective intervention strategy. The operational cost was 0.50 (US= 47) per capita per application. Proper water storage practices, focused IEC with <it>Poecilia </it>introductions and vector sanitation involving the local administration and community, is suggested as the best strategy for <it>Aedes </it>control.</p
Back reaction, covariant anomaly and effective action
In the presence of back reaction, we first produce the one-loop corrections
for the event horizon and Hawking temperature of the Reissner-Nordstr\"om black
hole. Then, based on the covariant anomaly cancelation method and the effective
action technique, the modified expressions for the fluxes of gauge current and
energy momentum tensor, due to the effect of back reaction, are obtained. The
results are consistent with the Hawking fluxes of a (1+1)-dimensional blackbody
at the temperature with quantum corrections, thus confirming the robustness of
the covariant anomaly cancelation method and the effective action technique for
black holes with back reaction.Comment: 17 page
Studies of the Decay B+- -> D_CP K+-
We report studies of the decay B+- -> D_CP K+-, where D_CP denotes neutral D
mesons that decay to CP eigenstates. The analysis is based on a 29.1/fb data
sample of collected at the \Upsilon(4S) resonance with the Belle detector at
the KEKB asymmetric e+ e- storage ring. Ratios of branching fractions of
Cabibbo-suppressed to Cabibbo-favored processes involving D_CP are determined
to be B(B- -> D_1 K-)/B(B- -> D_1 pi-)=0.125 +- 0.036 +- 0.010 and B(B- -> D_2
K-)/B(B- -> D_2 pi-)=0.119 +- 0.028 +- 0.006, where indices 1 and 2 represent
the CP=+1 and CP=-1 eigenstates of the D0 - anti D0 system, respectively. We
also extract the partial rate asymmetries for B+- -> D_CP K+-, finding A_1 =
0.29 +- 0.26 +- 0.05 and A_2 = -0.22 +- 0.24 +- 0.04.Comment: 10 pages, 2 figures, submitted to Physical Review Letter
Self-assembled amyloid fibrils with controllable conformational heterogeneity
Amyloid fibrils are a hallmark of neurodegenerative diseases and exhibit a conformational diversity that governs their pathological functions. Despite recent findings concerning the pathological role of their conformational diversity, the way in which the heterogeneous conformations of amyloid fibrils can be formed has remained elusive. Here, we show that microwave-assisted chemistry affects the self-assembly process of amyloid fibril formation, which results in their conformational heterogeneity. In particular, microwave-assisted chemistry allows for delicate control of the thermodynamics of the self-assembly process, which enabled us to tune the molecular structure of ??-lactoglobulin amyloid fibrils. The heterogeneous conformations of amyloid fibrils, which can be tuned with microwave-assisted chemistry, are attributed to the microwave-driven thermal energy affecting the electrostatic interaction during the self-assembly process. Our study demonstrates how microwave-assisted chemistry can be used to gain insight into the origin of conformational heterogeneity of amyloid fibrils as well as the design principles showing how the molecular structures of amyloid fibrils can be controlledopen0
Epigallocatechin-3-gallate suppresses the expression of HSP70 and HSP90 and exhibits anti-tumor activity in vitro and in vivo
<p>Abstract</p> <p>Background</p> <p>Epigallocatechin-3-gallate (EGCG), one of the major catechins in green tea, is a potential chemopreventive agent for various cancers. The aim of this study was to examine the effect of EGCG on the expression of heat shock proteins (HSPs) and tumor suppression.</p> <p>Methods</p> <p>Cell colony formation was evaluated by a soft agar assay. Transcriptional activity of HSP70 and HSP90 was determined by luciferase reporter assay. An EGCG-HSPs complex was prepared using EGCG attached to the cyanogen bromide (CNBr)-activated Sepharose 4B. <it>In vivo </it>effect of EGCG on tumor growth was examined in a xenograft model.</p> <p>Results</p> <p>Treatment with EGCG decreased cell proliferation and colony formation of MCF-7 human breast cancer cells. EGCG specifically inhibited the expression of HSP70 and HSP90 by inhibiting the promoter activity of HSP70 and HSP90. Pretreatment with EGCG increased the stress sensitivity of MCF-7 cells upon heat shock (44°C for 1 h) or oxidative stress (H<sub>2</sub>O<sub>2</sub>, 500 μM for 24 h). Moreover, treatment with EGCG (10 mg/kg) in a xenograft model resulted in delayed tumor incidence and reduced tumor size, as well as the inhibition of HSP70 and HSP90 expression.</p> <p>Conclusions</p> <p>Overall, these findings demonstrate that HSP70 and HSP90 are potent molecular targets of EGCG and suggest EGCG as a drug candidate for the treatment of human cancer.</p
The effects of tea extracts on proinflammatory signaling
BACKGROUND: Skin toxicity is a common side effect of radiotherapy for solid tumors. Its management can cause treatment gaps and thus can impair cancer treatment. At present, in many countries no standard recommendation for treatment of skin during radiotherapy exists. In this study, we explored the effect of topically-applied tea extracts on the duration of radiation-induced skin toxicity. We investigated the underlying molecular mechanisms and compared effects of tea extracts with the effects of epigallocatechin-gallate, the proposed most-active moiety of green tea. METHODS: Data from 60 patients with cancer of the head and neck or pelvic region topically treated with green or black tea extracts were analyzed retrospectively. Tea extracts were compared for their ability to modulate IL-1β, IL-6, IL-8, TNFα and PGE(2 )release from human monocytes. Effects of tea extracts on 26S proteasome function were assessed. NF-κB activity was monitored by EMSAs. Viability and radiation response of macrophages after exposure to tea extracts was measured by MTT assays. RESULTS: Tea extracts supported the restitution of skin integrity. Tea extracts inhibited proteasome function and suppressed cytokine release. NF-κB activity was altered by tea extracts in a complex, caspase-dependent manner, which differed from the effects of epigallocatechin-gallate. Additionally, both tea extracts, as well as epigallocatechin-gallate, slightly protected macrophages from ionizing radiation CONCLUSION: Tea extracts are an efficient, broadly available treatment option for patients suffering from acute radiation-induced skin toxicity. The molecular mechanisms underlying the beneficial effects are complex, and most likely not exclusively dependent on effects of tea polyphenols such as epigallocatechin-gallate
Targeting and killing of glioblastoma with activated T cells armed with bispecific antibodies
Abstract
Background
Since most glioblastomas express both wild-type EGFR and EGFRvIII as well as HER2/neu, they are excellent targets for activated T cells (ATC) armed with bispecific antibodies (BiAbs) that target EGFR and HER2.
Methods
ATC were generated from PBMC activated for 14 days with anti-CD3 monoclonal antibody in the presence of interleukin-2 and armed with chemically heteroconjugated anti-CD3×anti-HER2/neu (HER2Bi) and/or anti-CD3×anti-EGFR (EGFRBi). HER2Bi- and/or EGFRBi-armed ATC were examined for in vitro cytotoxicity using MTT and 51Cr-release assays against malignant glioma lines (U87MG, U118MG, and U251MG) and primary glioblastoma lines.
Results
EGFRBi-armed ATC killed up to 85% of U87, U118, and U251 targets at effector:target ratios (E:T) ranging from 1:1 to 25:1. Engagement of tumor by EGFRBi-armed ATC induced Th1 and Th2 cytokine secretion by armed ATC. HER2Bi-armed ATC exhibited comparable cytotoxicity against U118 and U251, but did not kill HER2-negative U87 cells. HER2Bi- or EGFRBi-armed ATC exhibited 50—80% cytotoxicity against four primary glioblastoma lines as well as a temozolomide (TMZ)-resistant variant of U251. Both CD133– and CD133+ subpopulations were killed by armed ATC. Targeting both HER2Bi and EGFRBi simultaneously showed enhanced efficacy than arming with a single BiAb. Armed ATC maintained effectiveness after irradiation and in the presence of TMZ at a therapeutic concentration and were capable of killing multiple targets.
Conclusion
High-grade gliomas are suitable for specific targeting by armed ATC. These data, together with additional animal studies, may provide the preclinical support for the use of armed ATC as a valuable addition to current treatment regimens
Feasibility of Image-Guided Radiotherapy for Elderly Patients with Locally Advanced Rectal Cancer
PURPOSE: The study aims to assess the tolerance of elderly patients (70 years or older) with locally advanced rectal cancers to image-guided radiotherapy (IGRT). A retrospective review of 13 elderly patients with locally advanced rectal cancer who underwent preoperative chemoradiation using IGRT was performed. Grade 3-4 acute toxicities, survival, and long-term complications were compared to 17 younger patients (<70 years) with the same disease stage. RESULTS: Grade 3-4 hematologic toxicities occurred in 7.6% and 0% (p = 0.4) and gastrointestinal toxicities, and, in 15.2% and 5% (p = 0.5), of elderly and younger patients, respectively. Surgery was aborted in three patients, two in the elderly group and one in the younger group. One patient in the elderly group died after surgery from cardiac arrhythmia. After a median follow-up of 34 months, five patients had died, two in the elderly and three in the younger group. The 3-year survival was 90.9% and 87.5% (p = 0.7) for the elderly and younger group respectively. Two patients in the younger group developed ischemic colitis and fecal incontinence. There was no statistically significant difference in acute and late toxicities as well as survival between the two groups. CONCLUSIONS AND CLINICAL RELEVANCE: Elderly patients with locally advanced rectal cancers may tolerate preoperative chemoradiation with IGRT as well as younger patients. Further prospective studies should be performed to investigate the potential of IGRT for possible cure in elderly patients with locally advanced rectal cancer
- …