277 research outputs found
Cavity locking with spatial modulation of optical phase front for laser stabilization
We study optical cavity locking for laser stabilization through spatial
modulation of the phase front of a light beam. A theoretical description of the
underlying principle is developed for this method and special attention is paid
to residual amplitude modulation (RAM) caused by experimental imperfections,
especially the manufacture errors of the spatial phase modulator. The studied
locking method owns the common advantages of the Pound-Drever-Hall method and
the tilt-locking one, and it can provide a more artful way to eliminate RAM
noise in phase modulation for the ultimate stability of lasers. In situations
where cost and portability are a practical issue, the studied method allows one
to realize compact laser stabilization systems locked to
Fabry-P\acute{\mbox{e}}rot cavities without use of expensive bulky devices,
such as signal generators and electro-optic modulators.Comment: 3 figure
Sustainable economic growth via human capital and cleaner energy: evidence from non-parametric panel methods
The association between resource rents and economic growth is one
of the key issues that have attracted the attention of both policymakers
and scholars. Several attempts have been made regarding
the association, yet the literature holds the gap. The present research
intends to explore the connection between natural resource volatility
and economic performance in seven (G-7) countries. For the time
frame from1990 to 2020, this study also examines the role of technological
innovation (TI), human capital (HCI), and research and development
budget for renewable energy (RER&D). Empirical results
asserted that the variables under study are cointegrated. Employing
a novel non-parametric panel quantile method of moments regression
and quantile-on-quantile, the outcomes propose that natural
resources volatility significantly affects EP throughout the quantiles.
This negative impact is valid for the aggregate panel of countries
and cross-sections. Natural resource volatility supports the resource
curse hypothesis for G7 economies. On the other hand, HCI and TI
are significant economic performance factors. From lower to higher
quantiles, the magnitude and significance levels increase. The variable
for cleaner energy investment is also positively related to economic
performance yet insignificant in the higher quantile. The
study recommends channeling natural resource rents to effectively
and fully transfer the full potential of natural resources to other real
sectors of the economy to fully utilize the benefit from it
Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): Emissions of particulate matter and sulfur dioxide from vehicles and brick kilns and their impacts on air quality in the Kathmandu Valley, Nepal
Air pollution is one of the most pressing environmental issues in the Kathmandu Valley, where the capital city of Nepal is located. We estimated emissions from two of the major source types in the valley (vehicles and brick kilns) and analyzed the corresponding impacts on regional air quality. First, we estimated the on-road vehicle emissions in the valley using the International Vehicle Emissions (IVE) model with local emissions factors and the latest available data for vehicle registration. We also identified the locations of the brick kilns in the Kathmandu Valley and developed an emissions inventory for these kilns using emissions factors measured during the Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) field campaign in April 2015. Our results indicate that the commonly used global emissions inventory, the Hemispheric Transport of Air Pollution (HTAP_v2.2), underestimates particulate matter emissions from vehicles in the Kathmandu Valley by a factor greater than 100. HTAP_v2.2 does not include the brick sector and we found that our sulfur dioxide (SO2) emissions estimates from brick kilns are comparable to 70 % of the total SO2 emissions considered in HTAP_v2.2. Next, we simulated air quality using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for April 2015 based on three different emissions scenarios: HTAP only, HTAP with updated vehicle emissions, and HTAP with both updated vehicle and brick kilns emissions. Comparisons between simulated results and observations indicate that the model underestimates observed surface elemental carbon (EC) and SO2 concentrations under all emissions scenarios. However, our updated estimates of vehicle emissions significantly reduced model bias for EC, while updated emissions from brick kilns improved model performance in simulating SO2. These results highlight the importance of improving local emissions estimates for air quality modeling. We further find that model overestimation of surface wind leads to underestimated air pollutant concentrations in the Kathmandu Valley. Future work should focus on improving local emissions estimates for other major and underrepresented sources (e.g., crop residue burning and garbage burning) with a high spatial resolution, as well as the model\u27s boundary layer representation, to capture strong spatial gradients of air pollutant concentrations
RIS-based IMT-2030 Testbed for MmWave Multi-stream Ultra-massive MIMO Communications
As one enabling technique of the future sixth generation (6G) network,
ultra-massive multiple-input-multiple-output (MIMO) can support high-speed data
transmissions and cell coverage extension. However, it is hard to realize the
ultra-massive MIMO via traditional phased arrays due to unacceptable power
consumption. To address this issue, reconfigurable intelligent surface-based
(RIS-based) antennas are an energy-efficient enabler of the ultra-massive MIMO,
since they are free of energy-hungry phase shifters. In this article, we report
the performances of the RIS-enabled ultra-massive MIMO via a project called
Verification of MmWave Multi-stream Transmissions Enabled by RIS-based
Ultra-massive MIMO for 6G (V4M), which was proposed to promote the evolution
towards IMT-2030. In the V4M project, we manufacture RIS-based antennas with
1024 one-bit elements working at 26 GHz, based on which an mmWave dual-stream
ultra-massive MIMO prototype is implemented for the first time. To approach
practical settings, the Tx and Rx of the prototype are implemented by one
commercial new radio base station and one off-the-shelf user equipment,
respectively. The measured data rate of the dual-stream prototype approaches
the theoretical peak rate. Our contributions to the V4M project are also
discussed by presenting technological challenges and corresponding solutions.Comment: 8 pages, 5 figures, to be published in IEEE Wireless Communication
No causal association between plasma cystatin C and cardiovascular diseases: Mendelian randomization analyses in UK biobank
BackgroundWe aimed to determine whether the plasma cystatin C is a causal risk factor for cardiovascular events, stroke, myocardial infarction (MI), and cardiovascular disease (CVD) mortality by conducting Mendelian randomization (MR) designs.MethodsOur study included 277,057 individuals free of CVDs or cancer at baseline in the UK Biobank. The genetic scores of plasma cystatin C comprising 67 single-nucleotide polymorphisms were calculated on the basis of data from a large genome-wide association study. By stratifying the genetic score, we conducted cox regression to assess the relationship between plasma cystatin C and CVDs. In this study, linear MR analysis was used to estimate the causal association between plasma cystatin C and CVDs.ResultsObservational analyses showed that plasma cystatin C concentrations were associated with the risk of CVDs [hazard ratios (HR) per standard deviation (SD) 1.09, 95% confidence interval (CI); 1.07–1.10] and CVD mortality (1.14, 1.11–1.17). Among CVDs, plasma cystatin C were associated with stroke (1.10, 1.08–1.11) and MI (1.08, 1.07–1.10). Linear MR analysis did not provide evidence of a causal association between plasma cystatin C and the risk of CVDs [odds ratio (OR) per SD 0.96, 95% CI;0.90–1.03], stroke (0.96, 0.93–1.01), MI (0.97, 0.91–1.03), and CVD mortality (0.98, 0.96–1.01), with consistent estimates from sensitivity analyses.ConclusionObservational findings indicated that higher plasma cystatin C is associated with a higher risk of CVDs; According to MR studies, there is no causal association between plasma cystatin C and the risk of CVDs and CVD mortality
Revisited and innovative perspectives of oral ulcer: from biological specificity to local treatment
Mouth ulcers, a highly prevalent ailment affecting the oral mucosa, leading to pain and discomfort, significantly impacting the patient’s daily life. The development of innovative approaches for oral ulcer treatment is of great importance. Moreover, a deeper and more comprehensive understanding of mouth ulcers will facilitate the development of innovative therapeutic strategies. The oral environment possesses distinct traits as it serves as the gateway to the digestive and respiratory systems. The permeability of various epithelial layers can influence drug absorption. Moreover, oral mucosal injuries exhibit distinct healing patterns compared to cutaneous lesions, influenced by various inherent and extrinsic factors. Furthermore, the moist and dynamic oral environment, influenced by saliva and daily physiological functions like chewing and speaking, presents additional challenges in local therapy. Also, suitable mucosal adhesion materials are crucial to alleviate pain and promote healing process. To this end, the review comprehensively examines the anatomical and structural aspects of the oral cavity, elucidates the healing mechanisms of oral ulcers, explores the factors contributing to scar-free healing in the oral mucosa, and investigates the application of mucosal adhesive materials as drug delivery systems. This endeavor seeks to offer novel insights and perspectives for the treatment of oral ulcers
Predictive value of PD-L1 and TMB for short-term efficacy prognosis in non-small cell lung cancer and construction of prediction models
ObjectiveTo investigate the correlation between programmed death ligand 1(PD-L1), tumor mutation burden (TMB) and the short-term efficacy and clinical characteristics of anti-PD-1 immune checkpoint inhibitor combination chemotherapy in NSCLC patients. The efficacy of the prediction model was evaluated.MethodsA total of 220 NSCLC patients receiving first-line treatment with anti-PD-1 immune checkpoint inhibitor combined with chemotherapy were retrospectively collected. The primary endpoint was short-term efficacy ORR. The correlation between short-term efficacy, PD-L1, TMB, and clinical characteristics using χ2 test or t-test was evaluated. Screen the independent prognostic factors using univariate and multivariate logistic regression analyses, and construct a nomogram prediction model using the “rms” package in R software. Using receiver operating characteristic (ROC) curve analysis to evaluate the independent Prognostic factors and the prediction model. Using decision curve analysis (DCA) to verify the superiority of the prediction model.ResultsThe mean values of PD-L1, TMB, neutrophils, lymphocytes, neutrophil-to-lymphocyte ratio, and albumin were the highest in the ORR group, PD-L1 expression and TMB correlated with epidermal growth factor receptor expression. Multivariate analyses showed that PD-L1, TMB, and neutrophil were independent prognostic factors for ORR. The area under the ROC curve (AUC) values of the ROC constructed based on these three indicators were 0.7104, 0.7139, and 0.7131, respectively. The AUC value under the ROC of the nomogram model was 0.813. The DCA of the model showed that all three indicators used together to build the prediction model of the net return were higher than those of the single indicator prediction model.ConclusionPD-L1, TMB, and neutrophils are independent prognostic factors for short-term efficacy. The nomogram prediction model constructed using these three indicators can further improve predictive efficacy of ICIs in patients with NSCLC
Artesunate induces necrotic cell death in schwannoma cells
Established as a potent anti-malaria medicine, artemisinin-based drugs have been suggested to have anti-tumour activity in some cancers. Although the mechanism is poorly understood, it has been suggested that artemisinin induces apoptotic cell death. Here, we show that the artemisinin analogue artesunate (ART) effectively induces cell death in RT4 schwannoma cells and human primary schwannoma cells. Interestingly, our data indicate for first time that the cell death induced by ART is largely dependent on necroptosis. ART appears to inhibit autophagy, which may also contribute to the cell death. Our data in human schwannoma cells show that ART can be combined with the autophagy inhibitor chloroquine (CQ) to potentiate the cell death. Thus, this study suggests that artemisinin-based drugs may be used in certain tumours where cells are necroptosis competent, and the drugs may act in synergy with apoptosis inducers or autophagy inhibitors to enhance their anti-tumour activity
Transcriptional regulation of gene expression during osmotic stress responses by the mammalian target of rapamycin
Although stress can suppress growth and proliferation, cells can induce adaptive responses that allow them to maintain these functions under stress. While numerous studies have focused on the inhibitory effects of stress on cell growth, less is known on how growth-promoting pathways influence stress responses. We have approached this question by analyzing the effect of mammalian target of rapamycin (mTOR), a central growth controller, on the osmotic stress response. Our results showed that mammalian cells exposed to moderate hypertonicity maintained active mTOR, which was required to sustain their cell size and proliferative capacity. Moreover, mTOR regulated the induction of diverse osmostress response genes, including targets of the tonicity-responsive transcription factor NFAT5 as well as NFAT5-independent genes. Genes sensitive to mTOR-included regulators of stress responses, growth and proliferation. Among them, we identified REDD1 and REDD2, which had been previously characterized as mTOR inhibitors in other stress contexts. We observed that mTOR facilitated transcription-permissive conditions for several osmoresponsive genes by enhancing histone H4 acetylation and the recruitment of RNA polymerase II. Altogether, these results reveal a previously unappreciated role of mTOR in regulating transcriptional mechanisms that control gene expression during cellular stress responses
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