6,310 research outputs found
Broadband enhancement of light harvesting in luminescent solar concentrator
Luminescent solar concentrator (LSC) can absorb large-area incident sunlight,
then emit luminescence with high quantum efficiency, which finally be collected
by a small photovoltaic (PV) system. The light-harvesting area of the PV system
is much smaller than that of the LSC system, potentially improving the
efficiency and reducing the cost of solar cells. Here, based on Fermi-golden
rule, we present a theoretical description of the luminescent process in
nanoscale LSCs where the conventional ray-optics model is no longer applicable.
As an example calculated with this new model, we demonstrate that a slot
waveguide consisting of a nanometer-sized low-index slot region sandwiched by
two high-index regions provides a broadband enhancement of light harvesting by
the luminescent centers in the slot region. This is because the slot waveguide
can (1) greatly enhance the spontaneous emission due to the Purcell effect, (2)
dramatically increase the effective absorption cross-section of luminescent
centers, and (3) strongly improve the quantum efficiency of luminescent
centers. It is found that about 80% solar photons can be ultimately converted
to waveguide-coupled luminescent photons even for a low luminescent quantum
efficiency of 0.5. This LSC is potential to construct a tandem structure which
can absorb nearly full-spectrum solar photons, and also may be of special
interest for building integrated nano-PV applications
Effects of recombinant adenovirus-mediated hypoxia-inducible factor-1alpha gene on proliferation and differentiation of endogenous neural stem cells in rats following intracerebral hemorrhage
AbstractObjectiveTo investigate the effects of adenovirus (Ad)-mediated hypoxia-inducible factor-1alpha (HIF-1α) gene on proliferation and differentiation of endogenous neural stem cells (NSCs) in rats following intracerebral hemorrhage (ICH) and the underlying mechanisms.MethodsA total of 120 specific pathogen-free, adult, male Sprague-Dawley rats were included in this study. After establishment of ICH models in rats, PBS, Ad, or Ad-HIF-1α was administered via the ischemic ventricle. On the 1st, 7th, 14th, 21st and 28th d after ICH, rat neurological deficits were scored, doublecortin (DCX) expression in the subventricular zone cells was detected by immunohistochemical staining, and 5-bromo-2'-deoxyuridine (BrdU)-, BrdU/DCX-, and BrdU/glial fibrillary acidic protein-positive cells in the subventricular zone were counted using immumofluorescence method among PBS, Ad, and Ad-HIF-1α groups.ResultsOn the 7th, 14th, 21st and 28th d after ICH, neurological deficit scores in the Ad-HIF-1α group were significantly lower than in the PBS and Ad groups (P<0.05). In the Ad-HIF-1α group, DCX expression was significantly increased on the 7th d, peaked on the 14th d, and then gradually decreased. In the Ad-HIF-1α group, BrdU-positive cells were significantly increased over time course, and significant difference in BrdU-positive cell counts was observed when compared with the PBS and Ad groups at each time point (P<0.01 or 0.05). On the 7th, 14th, 21st and 28th d after ICH, the number of DCX-, BrdU-, BrdU/DCX-, and BrdU/DCX-positive cells in the Ad-HIF-1α group was significantly greater than in the PBS and Ad groups (P<0.05).ConclusionsHIF-1α gene can promote the proliferation, migration and differentiation of endogenous neural stem cells after ICH, thereby contributing to neurofunctional recovery after ICH
(E)-1-(4-Methylphenyl)-3-[(1-phenylethylidene)amino]thiourea
In the title compound, C16H17N3S, the aminothiourea unit is nearly planar (r.m.s. deviation = 0.0425 Å), and is twisted with respect to the tolyl and phenyl rings by 57.84 (7) and 15.88 (14)°, respectively; the tolyl and phenyl rings are twisted by 65.64 (11)° to each other. Intermolecular N—H⋯S and weak C—H⋯S hydrogen bonds are present in the crystal structure
NLRC5 knockdown in chicken macrophages alters response to LPS and poly (I:C) stimulation
<p>Abstract</p> <p>Background</p> <p>NLRC5 is a member of the CARD domain containing, nucleotide-binding oligomerization (NOD)-like receptor (NLR) family, which recognizes pathogen-associated molecular patterns (PAMPs) and initiates an innate immune response leading to inflammation and/or cell death. However, the specific role of <it>NLRC5 </it>as a modulator of the inflammatory immune response remains controversial. It has been reported to be a mediator of type I IFNs, NF-kB, and <it>MHC class I </it>gene. But no study on <it>NLRC5 </it>function has been reported to date in chickens. In the current study, we investigated the role of <it>NLRC5 </it>in the regulation of <it>IFNA</it>, <it>IFNB</it>, <it>IL-6</it>, and <it>MHC class I </it>in the chicken HD11 macrophage cell line, by using RNAi technology. HD11 cells were transfected with one of five siRNAs (s1, s2, s3, negative-siRNA, or a mixture of s1, s2, s3-siRNAs). After 24 hours, cells were exposed to LPS or poly (I:C) or a vehicle control. Gene expression of <it>NLRC5</it>, <it>IFNA</it>, <it>IFNB</it>, <it>IL-6</it>, and <it>MHC class I </it>at 2, 4, 6, and 8 hours post stimulation (hps) was quantified by qPCR.</p> <p>Results</p> <p>The expression of <it>NLRC5</it>, <it>IFNA</it>, <it>IFNB</it>, and <it>IL-6 </it>genes in negative irrelevant transfection controls was up-regulated at 2 hps after LPS treatment compared to the vehicle controls. S3-siRNA effectively knocked down <it>NLRC5 </it>expression at 4 hps, and the expression of <it>IFNA </it>and <it>IFNB </it>(but not <it>IL-6 </it>and <it>MHC class I</it>) was also down-regulated at 4 hps in s3-siRNA transfected cells, compared to negative irrelevant transfection controls. Stimulation by LPS appeared to relatively restore the decrease in <it>NLRC5</it>, <it>IFNA</it>, and <it>IFNB </it>expression, but the difference is not significant.</p> <p>Conclusions</p> <p>Functional characterization of chicken <it>NLRC5 </it>in an <it>in vitro </it>system demonstrated its importance in regulating intracellular molecules involved in inflammatory response. The knockdown of <it>NLRC5 </it>expression negatively mediates gene expression of <it>IFNA </it>and <it>IFNB </it>in the chicken HD11 cell line; therefore, <it>NLRC5 </it>likely has a role in positive regulation of <it>IFNA </it>and <it>IFNB </it>expression. No direct relationship was found between <it>NLRC5 </it>knockdown and <it>IL-6 </it>and <it>MHC class I </it>expression. Future studies will further clarify the roles of <it>NLRC5 </it>and other NLRs in infectious diseases of chickens and may increase the efficacy of antiviral vaccine design.</p
Locally Advanced Oncocytic Carcinoma of the Nasal Cavity Treated With Surgery and Intensity-modulated Radiotherapy
Oncocytic carcinomas of the nasal cavity are extremely rare. We report 1 patient whose primary tumor and neck lymphadenopathies were under control nearly 2 years after combined surgery and radiotherapy. An 80-year-old man with a history of nasal oncocytoma had received excision twice previously. Computed tomography demonstrated locally advanced recurrent tumor invading the paranasal sinuses and orbit with lymphadenopathies in the right neck. Skull base surgery was performed. Pathological examination revealed oncocytic carcinoma. Positron emission tomography showed hypermetabolic lesions in the surgical bed and right neck. The patient subsequently received intensity-modulated radiotherapy to the primary site and the whole neck. Follow-up computed tomography 4 months later showed marked shrinkage of the neck lymphadenopathies. There was no progression after nearly 2 years. Although these tumors have historically been regarded as radioresistant, the combined treatment of surgery followed by radiotherapy may offer the best chance for control of locally advanced disease
Effects of polymer molecular weight on relative oral bioavailability of curcumin
Yin-Meng Tsai,1 Wan-Ling Chang-Liao,1 Chao-Feng Chien,1 Lie-Chwen Lin,1,2 Tung-Hu Tsai,1,31Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, 2National Research Institute of Chinese Medicine, 3Department of Education and Research, Taipei City Hospital, Taipei, TaiwanBackground: Polylactic-co-glycolic acid (PLGA) nanoparticles have been used to increase the relative oral bioavailability of hydrophobic compounds and polyphenols in recent years, but the effects of the molecular weight of PLGA on bioavailability are still unknown. This study investigated the influence of polymer molecular weight on the relative oral bioavailability of curcumin, and explored the possible mechanism accounting for the outcome.Methods: Curcumin encapsulated in low (5000&ndash;15,000) and high (40,000&ndash;75,000) molecular weight PLGA (LMw-NPC and HMw-NPC, respectively) were prepared using an emulsification-solvent evaporation method. Curcumin alone and in the nanoformulations was administered orally to freely mobile rats, and blood samples were collected to evaluate the bioavailability of curcumin, LMw-NPC, and HMw-NPC. An ex vivo experimental gut absorption model was used to investigate the effects of different molecular weights of PLGA formulation on absorption of curcumin. High-performance liquid chromatography with diode array detection was used for quantification of curcumin in biosamples.Results: There were no significant differences in particle properties between LMw-NPC and HMw-NPC, but the relative bioavailability of HMw-NPC was 1.67-fold and 40-fold higher than that of LMw-NPC and conventional curcumin, respectively. In addition, the mean peak concentration (Cmax) of conventional curcumin, LMw-NPC, and HMw-NPC was 0.028, 0.042, and 0.057 &micro;g/mL, respectively. The gut absorption study further revealed that the HMw-PLGA formulation markedly increased the absorption rate of curcumin in the duodenum and resulted in excellent bioavailability compared with conventional curcumin and LMw-NPC.Conclusion: Our findings demonstrate that different molecular weights of PLGA have varying bioavailability, contributing to changes in the absorption rate at the duodenum. The results of this study provide the rationale for design of a nanomedicine delivery system to enhance the bioavailability of water-insoluble pharmaceutical compounds and functional foods.Keywords: absorption, duodenum, molecular weight, poly(lactic-co-glycolic acid), PLGA, relative oral bioavailabilit
Metrology Camera System of Prime Focus Spectrograph for Subaru Telescope
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber
spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS
will cover a 1.3 degree diameter field with 2394 fibers to complement the
imaging capabilities of Hyper SuprimeCam. To retain high throughput, the final
positioning accuracy between the fibers and observing targets of PFS is
required to be less than 10um. The metrology camera system (MCS) serves as the
optical encoder of the fiber motors for the configuring of fibers. MCS provides
the fiber positions within a 5um error over the 45 cm focal plane. The
information from MCS will be fed into the fiber positioner control system for
the closed loop control. MCS will be located at the Cassegrain focus of Subaru
telescope in order to to cover the whole focal plane with one 50M pixel Canon
CMOS camera. It is a 380mm Schmidt type telescope which generates a uniform
spot size with a 10 micron FWHM across the field for reasonable sampling of
PSF. Carbon fiber tubes are used to provide a stable structure over the
operating conditions without focus adjustments. The CMOS sensor can be read in
0.8s to reduce the overhead for the fiber configuration. The positions of all
fibers can be obtained within 0.5s after the readout of the frame. This enables
the overall fiber configuration to be less than 2 minutes. MCS will be
installed inside a standard Subaru Cassgrain Box. All components that generate
heat are located inside a glycol cooled cabinet to reduce the possible image
motion due to heat. The optics and camera for MCS have been delivered and
tested. The mechanical parts and supporting structure are ready as of spring
2016. The integration of MCS will start in the summer of 2016.Comment: 11 pages, 15 figures. SPIE proceeding. arXiv admin note: text overlap
with arXiv:1408.287
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