718 research outputs found

    2.45 GHz Active Isolator based on asymmetric coupler

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    An active isolator achieving both high isolation and low insertion loss at 2.45 GHz is proposed. The isolator is based on an asymmetric coupler and is designed to leverage the gain and reverse isolation of an amplifier and coupling coefficients between the input and output of the coupler. The insertion loss and isolation of the isolator are enhanced by using the coefficients, and the power level with optimal isolation can be determined for a target specification. The asymmetric coupler increases the power handling capability of the proposed isolator that has a low coupling coefficient and achieves highly efficient isolation with a high coupling coefficient. Electromagnetic-circuit co-simulation results show that the proposed isolator with operation stability has ≄40 dB isolation and <1 dB insertion loss for input power between 0−8 dBm

    An Experiment of Game Promotion and Selling Using Twitter

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    — The combination of the internet, social media and mobile phones makes the social mobile game is becoming a huge market with high growth rates from year to year. This trend is attract the game developers/publisher vying to enter this game market including in Indonesia. In other hand, Twitter as one of social media has a major influence on consumer purchase decisions especially in social mobile games. Consumer seeking recommendation about game that they want to download based on their friend recommendation and content that their consume in social media before visit online store. As for Indonesia game developers most of their marketing activities were more to game gathering or events, there is little that effectively use social media as marketing channel. Social media adoption including twitter in Indonesia game developer is at stage of connectivity and proff of company existance. The purpose of this research is to know does using twitter as social media marketing have effect to influence consumer and download mobile game. In this research, experiment methodology was employed. Experiment was choosed because to have real insight about the effect of twitter as social media marketing in building games relationship with consumer and increase the number of game download. Stack The Stuff, game from PT. Nightspade was choosed as research object. The implementation using OASIS frawework as guidance. The results from the experiments in this research measured using Social Model Exposure-Engagement-Influence-Action from Don Bartholomew.Twitter as media marketing executed by carrying experiment 1 (15 August 2012 - 15 September 2012) with buzzing methods first, after it finish, followed by experiment 2 (22 September - 22 October 2012) with tweeting and offering method. Then, both experiment results compared to know which the better Twitter marketing method. The measurement using several tools, namely TweetLevel, Sprout Social, and downloads data. With confidence level 95%, our results suggested that twitter as media marketing with buzzing method have effect to increase game download and tweeting and offering method have effect to increase product engagement and influence in Twitter. Furthermore, in the end of research, there are recommendations to implement twitter as social media marketing for small-middle sized company like Indonesia game developer

    A Review of a Recent Meta-Analysis Study on Obstructive Sleep Apnea

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    This paper summarizes a recent meta-analysis of various topics in obstructive sleep apnea (OSA). In addition to cardiovascular disease and neurocognitive dysfunction, a wide variety of diseases have been associated with OSA, and associations with cancer have also been reported. Although continuous positive airway pressure is a very effective treatment, the results have shown that it does not reduce the incidence of various complications. It has been reported that uvulopalatopharyngoplasty was effective, and robotic surgery for the tongue root and hypoglossal nerve stimulation were also effective. The effectiveness of various medications to reduce daytime sleepiness has also been demonstrated. Although exercise lowered the apnea-hypopnea index, it was not related to changes in body composition, and it was also reported that exercise combined with weight control were effective. Additionally, interesting and clinically meaningful meta-analysis results were summarized and presented

    Helical tomotherapy with concurrent capecitabine for the treatment of inoperable pancreatic cancer

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    <p>Abstract</p> <p>Background</p> <p>Helical tomotherapy, an advanced intensity-modulated radiation therapy with integrated CT imaging, permits highly conformal irradiation with sparing of normal tissue. Capecitabine, a pro-drug of 5-FU that induces thymidine phosphorylase can achieve higher levels of intracellular 5-FU when administered concurrently with radiation. We evaluated the feasibility as well as the clinical outcome of concurrent administration of capecitabine with tomotherapy in patients with advanced pancreatic cancer.</p> <p>Methods</p> <p>Nineteen patients with advanced pancreatic cancer including primarily unresectable disease and recurrence after curative surgery were included in the study. Two planning target volumes (PTV) were entered: PTV1 is gross tumor volume; and PTV2, the volume of the draining lymph nodes. The total doses to target 1 and target 2 were 55 and 50 Gy, respectively. Capecitabine at 1600 mg/m<sup>2</sup>/day was administered on each day of irradiation.</p> <p>Results</p> <p>Twenty six measurable lesions were evaluated. Overall in-field response rate was 42.3%; partial responses were achieved in 53.3% of the pancreatic masses, 28.6% of distant metastatic lesions and 25.0% of regional lymph nodes. The median duration of follow-up after tomotherapy was 6.5 months. None of the lesions showed in-field progression. Treatment was well tolerated with only minor toxicities such as grade 1 nausea (one patient), grade 1 hand-foot syndrome (one patient) and grade 1/2 fatigue (three patients).</p> <p>Conclusions</p> <p>Helical tomotherapy with concurrent capecitabine is a feasible option without significant toxicities in patients with advanced pancreatic cancer. We achieved excellent conformal distribution of radiation doses and minimal treatment-related toxicities with promising target volume responses.</p

    Protective effects of Scutellaria baicalensis Georgi against hydrogen peroxide-induced DNA damage and apoptosis in HaCaT human skin keratinocytes

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    Oxidative stress due to excessive accumulation of reactive oxygen species (ROS) is one of the risk factors for the development of several chronic diseases. In this study, we investigated the protective effects of Scutellaria bai- calensis rhizome ethanol extract (SBRE) against oxidative stress-induced cellular damage and elucidated the un- derlying mechanisms in the HaCaT human skin keratinocyte cell line. Our results revealed that treatment with SBRE prior to hydrogen peroxide (H2O2) exposure significantly increased viability of aCaT cells. SBRE also effectively attenuated H2O2-induced comet tail formation and inhibited the H2O2-induced phosphorylation levels of the histone ÎłH2AX, as well as the number of apoptotic bodies and Annexin V-positive cells. In addition, SBRE exhibited scavenging activity against intracellular ROS generation and restored the mitochondrial membrane po- tential loss by H2O2. Moreover, H2O2 enhanced the cleavage of caspase-3 and degradation of poly (ADP-ribose)- polymerase, a typical substrate protein of activated caspase-3, as well as DNA fragmentation; however, these events were almost totally reversed by pretreatment with SBRE. Furthermore, SBRE increased the levels of heme oxygenase-1 (HO-1), which is a potent antioxidant enzyme, associated with the induction of nuclear fac- tor-erythroid 2-related factor 2 (Nrf2). According to our data, SBRE is able to protect HaCaT cells from H2O2- induced DNA damage and apoptosis through blocking cellular damage related to oxidative stress through a mech-anism that would affect ROS elimination and activating the Nrf2/HO-1 signaling pathway

    Practical Review of Olfactory Training and COVID-19

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    Olfactory disorders one of the most frequent distinctive symptoms of COVID-19 infection. COVID-19-induced olfactory disorder can be classified as post-infectious olfactory dysfunction (PIOD). The effect of drugs on olfactory disorder following upper respiratory infection, including PIOD, has not been clearly established, which adds to the difficulty with treating the disorder. However, the effect of olfactory training on PIOD has been confirmed by numerous studies. As such, olfactory training is gaining attention, and has taken on greater importance, as the sole treatment for COVID-19–induced olfactory disorder in this pandemic age. This review describes the effect of olfactory training for COVID-19–induced olfactory disorder by analyzing the relevant literature

    Synergistic surface modification for high-efficiency perovskite nanocrystal light-emitting diodes: divalent metal ion doping and halide-based ligand passivation

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    Surface defects of metal halide perovskite nanocrystals (PNCs) substantially compromise the optoelectronic performances of the materials and devices via undesired charge recombination. However, those defects, mainly the vacancies, are structurally entangled with each other in the PNC lattice, necessitating a delicately designed strategy for effective passivation. Here, a synergistic metal ion doping and surface ligand exchange strategy is proposed to passivate the surface defects of CsPbBr3 PNCs with various divalent metal (e.g., Cd2+, Zn2+, and Hg2+) acetate salts and didodecyldimethylammonium (DDA+) via one-step post-treatment. The addition of metal acetate salts to PNCs is demonstrated to suppress the defect formation energy effectively via the ab initio calculations. The developed PNCs not only have near-unity photoluminescence quantum yield and excellent stability but also show luminance of 1175 cd m−2, current efficiency of 65.48 cd A−1, external quantum efficiency of 20.79%, wavelength of 514 nm in optimized PNC light-emitting diodes with Cd2+ passivator and DDA ligand. The “organic–inorganic” hybrid engineering approach is completely general and can be straightforwardly applied to any combination of quaternary ammonium ligands and source of metal, which will be useful in PNC-based optoelectronic devices such as solar cells, photodetectors, and transistors
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