1,178 research outputs found
Sub-GeV millicharge dark matter from the hidden sector
We conduct a comprehensive study on the sub-GeV millicharge dark matter
produced through the freeze-in mechanism. We discuss in general the mixing
mechanism, encompassing both kinetic mixing and mass mixing, between the
hidden sector and the standard model, which can generate millicharge
carried by the dark fermions from the hidden sector. We discuss in depth how
such millicharge is generated, and clarify several misunderstandings regarding
this subject in the literature. Without employing an effective field theory
approach, where the photon field directly mixed with the additional , we
analyze a general renormalizable model and investigate the complete evolution
of the hidden sector particles. Due to the substantial self-interactions among
hidden sector particles, the evolution of the hidden sector temperature plays a
crucial role, which is addressed concurrently with the number densities of
hidden sector particles by solving a set of coupled Boltzmann equations. We
thoroughly examine eight benchmark models from six distinct cases. Some of our
key findings from the analysis of these benchmark models may be generalizable
and applicable to broader freeze-in scenarios. We also explore the possibility
that the (keV) dark photon is a viable dark matter
candidate, even though it can contribute at most to the total
observed dark matter relic density.Comment: 55 pages, 13 figure
Clinical investigation on angle-closure glaucoma patients with cataract treated by phacoemulsification combined with trabeculectomy
AIM: To investigate the effectiveness of phacoemulsification with intraocular lens(IOL)implantation combined with trabeculectomy in patients with cataract and angle-closure glaucoma.<p>METHODS: In 36 cases(46 eyes)of angle-closure glaucoma with cataract, phacoemulsification with foldable IOL implantation combined with trabeculectomy was performed. Data of pre- and post-operation, including visual acuity, intraocular pressure, filtering bleb, anterior chamber depth, chamber angle, and funds were all recorded and analyzed in detail.<p>RESULTS: During the follow-up of 3 months to 2 years,visual acuity of 43 eyes(93.5%)got improved, and intraocular pressure in 44 eyes(95.7%)were controlled in normal range(<21mmHg). Mean anterior chamber depth of 35 patients(46 eyes)got deeper from 2.1mm to 3.8mm(average 2.1±0.3mm to 3.8±0.4mm)after operation, with chamber angle opened to some extent. Six eyes(13.0%)got mild to moderate corneal edema, without corneal endothelial decompensation.<p>CONCLUSION: Phacoemulsification with IOL implantation combined with trabeculectomy is an effective and safe surgical technique for patients with angle-closure glaucoma and cataract, with satisfied control of intraocular pressure, deepening of anterior chamber, opening of anterior chamber angle, and improving visual function
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A Novel Aptamer LL4A Specifically Targets Vemurafenib-Resistant Melanoma through Binding to the CD63 Protein.
Melanoma is a highly aggressive tumor with a poor prognosis, and half of all melanoma patients harbor BRAF mutations. A BRAF inhibitor, vemurafenib (PLX4032), has been approved by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) to treat advanced melanoma patients with BRAFV600E mutation. However, the efficacy of vemurafenib is impeded by adaptive resistance in almost all patients. In this study, using a cell-based SELEX (systematic evolution of ligands by exponential enrichment) strategy, we obtained a DNA aptamer (named LL4) with high affinity and specificity against vemurafenib-resistant melanoma cells. Optimized truncated form (LL4A) specifically binds to vemurafenib-resistant melanoma cells with dissociation constants in the nanomolar range and with excellent stability and low toxicity. Meanwhile, fluorescence imaging confirmed that LL4A significantly accumulated in tumors formed by vemurafenib-resistant melanoma cells, but not in control tumors formed by their corresponding parental cells in vivo. Further, a transmembrane protein CD63 was identified as the binding target of aptamer LL4A using a pull-down assay combined with the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. CD63 formed a supramolecular complex with TIMP1 and β1-integrin, activated the nuclear factor кB (NF-кB) and mitogen-activated protein kinase (MAPK) signaling pathways, and contributed to vemurafenib resistance. Potentially, the aptamer LL4A may be used diagnostically and therapeutically in humans to treat targeted vemurafenib-resistant melanoma
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Ceiling-fan-integrated air conditioning: Airflow and temperature characteristics of a sidewall-supply jet interacting with a ceiling fan
Ceiling-Fan-Integrated Air Conditioning (CFIAC) is a proposed system that can greatly increase buildings’ cooling efficiency. In it, terminal supply ducts and diffusers are replaced by vents/nozzles, jetting supply air toward ceiling fans that serve to mix and distribute it within the room. Because of the fans’ air movement, the system provides comfort at higher room temperatures than in conventional commercial/ institutional/retail HVAC. We have experimentally evaluated CFIAC in a test room. This paper covers the distributions of air-speed, temperature, and calculated comfort level throughout the room. Two subsequent papers report tests of human subject comfort and ventilation effectiveness in the same experimental conditions. The room’s supply air emerged from a high-sidewall vent directed toward a ceiling fan on the jet centerline; we also tested this same jet on a fan located off to the side of the jet. Primary variables are: ceiling fan flow volumes in downward and upward directions, supply air volume, and room-vs-supply temperature difference. Velocity, turbulence, and temperature distributions are presented for vertical and horizontal transects of the room. The occupied zone is then evaluated for velocity and temperature non-uniformity, and for comfort as predicted by the ASHRAE Standard 55 elevated air speed method. We show that temperatures are well-mixed and uniform across the room for all of the fan-on configurations, for fans both within or out of the supply jet centerline. The ceiling fan flow dominates the CFIAC airflow, and even though non-uniform is capable of providing comfortable conditions throughout the occupied area of the room
Dibromidobis(1,10-phenanthroline-κ2 N,N′)cadmium(II)
The title compound, [CdBr2(C12H8N2)2], synthesized by the hydrothermal reaction of Cd(CH3COO)2·2H2O with NaBr and 1,10-phenanthroline, has the CdII cation coordinated by two Br− anions and four N atoms from two 1,10-phenanthroline ligands in a distorted octahedral geometry. The crystal packing is stabilized by intermolecular π–π interactions with centroid–centroid distances 3.572 (1) and 3.671 (1) Å together with C—H⋯Br hydrogen bonds
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