52 research outputs found

    The Wide Integral Field Infrared Spectrograph: Commissioning Results and On-sky Performance

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    We have recently commissioned a novel infrared (0.91.70.9-1.7 μ\mum) integral field spectrograph (IFS) called the Wide Integral Field Infrared Spectrograph (WIFIS). WIFIS is a unique instrument that offers a very large field-of-view (50^{\prime\prime} x 20^{\prime\prime}) on the 2.3-meter Bok telescope at Kitt Peak, USA for seeing-limited observations at moderate spectral resolving power. The measured spatial sampling scale is 1×1\sim1\times1^{\prime\prime} and its spectral resolving power is R2,500R\sim2,500 and 3,0003,000 in the zJzJ (0.91.350.9-1.35 μ\mum) and HshortH_{short} (1.51.71.5-1.7 μ\mum) modes, respectively. WIFIS's corresponding etendue is larger than existing near-infrared (NIR) IFSes, which are mostly designed to work with adaptive optics systems and therefore have very narrow fields. For this reason, this instrument is specifically suited for studying very extended objects in the near-infrared such as supernovae remnants, galactic star forming regions, and nearby galaxies, which are not easily accessible by other NIR IFSes. This enables scientific programs that were not originally possible, such as detailed surveys of a large number of nearby galaxies or a full accounting of nucleosynthetic yields of Milky Way supernova remnants. WIFIS is also designed to be easily adaptable to be used with larger telescopes. In this paper, we report on the overall performance characteristics of the instrument, which were measured during our commissioning runs in the second half of 2017. We present measurements of spectral resolving power, image quality, instrumental background, and overall efficiency and sensitivity of WIFIS and compare them with our design expectations. Finally, we present a few example observations that demonstrate WIFIS's full capability to carry out infrared imaging spectroscopy of extended objects, which is enabled by our custom data reduction pipeline.Comment: Published in the Proceedings of SPIE Astronomical Telescopes and Instrumentation 2018. 17 pages, 13 figure

    Prime Focus Spectrograph (PFS): the metrology camera system

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    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 10 µ m. The metrology camera system (MCS) serves as the optical encoder of the fiber positioners for configuring of fibers. The MCS locates at the Cassegrain focus of the Subaru telescope to cover the whole focal plane with one 50M pixel CMOS sensor. The information from MCS will be fed into the fiber positioner control system for closed loop control. The MCS was delivered to Subaru Observatory in Apr. 2018 and it had two engineering runs in Oct. 2018 and Aug. 2019. The 1st engineering run concluded that the original mirror supports need to be improved to provide better image quality. The newly designed mirror supports were installed before the 2nd engineering run. The 2nd engineering run result shows that the MCS overall position accuracy is better than 4μm and the image processing time is less than 4 seconds. The MCS is ready for the system integration with other PFS components

    Increased Risk of Vascular Events in Emergency Room Patients Discharged Home with Diagnosis of Dizziness or Vertigo: A 3-Year Follow-Up Study

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    BACKGROUND: Dizziness and vertigo symptoms are commonly seen in emergency room (ER). However, these patients are often discharged without a definite diagnosis. Conflicting data regarding the vascular event risk among the dizziness or vertigo patients have been reported. This study aims to determine the risk of developing stroke or cardiovascular events in ER patients discharged home with a diagnosis of dizziness or vertigo. METHODOLOGY: A total of 25,757 subjects with at least one ER visit in 2004 were identified. Of those, 1,118 patients were discharged home with a diagnosis of vertigo or dizziness. A Cox proportional hazard model was performed to compare the three-year vascular event-free survival rates between the dizziness/vertigo patients and those without dizziness/vertigo after adjusting for confounding and risk factors. RESULTS: We identified 52 (4.7%) vascular events in patients with dizziness/vertigo and 454 (1.8%) vascular events in patients without dizziness/vertigo. ER patients discharged home with a diagnosis of vertigo or dizziness had 2-fold (95% confidence interval [CI], 1.35-2.96; p<0.001) higher risk of stroke or cardiovascular events after adjusting for patient characteristics, co-morbidities, urbanization level of residence, individual socio-economic status, and initially taking medications after the onset of dizziness or vertigo during the first year. CONCLUSIONS: ER patients discharged home with a diagnosis of dizziness or vertigo were at a increased risk of developing subsequent vascular events than those without dizziness/vertigo after the onset of dizziness or vertigo. Further studies are warranted for developing better diagnostic and follow-up strategies in increased risk patients

    Observational Studies of Interacting Galaxies and the Development of the Wide Integral Field Infrared Spectrograph

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    Interacting galaxies are thought to be the essential building blocks of elliptical galaxies under the hierarchical galaxy formation scenario. The goal of my dissertation is to broaden our understanding of galaxy merger evolution through both observational studies and instrument developments. Observationally, I approach the goal photometrically and spectroscopically. The photometric studies better constrain the number density evolution of wet and dry mergers through five CFHTLS broad band photometry up to z~1. Meanwhile, by comparing the merger and elliptical galaxy mass density function, I discovered that the most massive mergers are not all formed via merging processes, unless the merging timescale is much longer than the expected value. Spectroscopically, the kinematic properties of close pair galaxies were studied to understand how star formation were quenched at z~0.5. I discovered that the number of red-red pairs are rare, which does not support the gravitational quenching mechanism suggested by the hot halo model. In instrumentation, one efficient way to study galaxy mergers is to use the integral field spectroscopic technique, capitalizing its intrinsic capability of obtaining 2-D spectra effectively. However, the currently available integral field spectrographs are inadequate to provide the required combination of integral field size and spectral resolution for merger studies. I, therefore, have developed two optical designs of a wide integral field infrared spectrograph (WIFIS), which I call WIFIS1 and WIFIS2, to satisfy the requirements of merger studies. Both the designs provide an integral field of 12" x 5" on 10-m telescopes (or equivalently 52" x 20" on 2.3-m telescopes). WIFIS1 delivers spectral resolving powers of 5,500 covering each of JHK bands in a single exposure; WIFIS2 does a lower power of 3,000 focusing on a shorter wavebands of zJ and H bands. All the WIFIS2 optical components have either been or being fabricated, and some of the components have been characterized in the laboratory, including its integral field unit, gratings, and mirrors. The expected completion of WIFIS based on WIFIS2 is 2013 summer, which will be followed by WIFIS1-based spectrograph in a few years.Ph

    Novel Evidence of Acute Kidney Injury in COVID-19

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    The coronavirus 2019 (COVID-19) pandemic has caused a huge impact on health and economic issues. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes cellular damage by entry mediated by the angiotensin-converting enzyme 2 of the host cells and its conjugation with spike proteins of SARS-CoV-2. Beyond airway infection and acute respiratory distress syndrome, acute kidney injury is common in SARS-CoV-2-associated infection, and acute kidney injury (AKI) is predictive to multiorgan dysfunction in SARS-CoV-2 infection. Beyond the cytokine storm and hemodynamic instability, SARS-CoV-2 might directly induce kidney injury and cause histopathologic characteristics, including acute tubular necrosis, podocytopathy and microangiopathy. The expression of apparatus mediating SARS-CoV-2 entry, including angiotensin-converting enzyme 2, transmembrane protease serine 2 (TMPRSS2) and a disintegrin and metalloprotease 17 (ADAM17), within the renal tubular cells is highly associated with acute kidney injury mediated by SARS-CoV-2. Both entry from the luminal and basolateral sides of the renal tubular cells are the possible routes for COVID-19, and the microthrombi associated with severe sepsis and the dysregulated renin&ndash;angiotensin&ndash;aldosterone system worsen further renal injury in SARS-CoV-2-associated AKI. In the podocytes of the glomerulus, injured podocyte expressed CD147, which mediated the entry of SARS-CoV-2 and worsen further foot process effacement, which would worsen proteinuria, and the chronic hazard induced by SARS-CoV-2-mediated kidney injury is still unknown. Therefore, the aim of the review is to summarize current evidence on SARS-CoV-2-associated AKI and the possible pathogenesis directly by SARS-CoV-2

    Efficacy of Prenatal Yoga in the Treatment of Depression and Anxiety during Pregnancy: A Systematic Review and Meta-Analysis

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    Women commonly suffer from depression during pregnancy. For reducing depression, yoga seems to be more suitable for pregnant women than other physical activities because of its low exercise intensity. The objective of this study was to assess the efficacy of prenatal yoga on the treatment of depression during pregnancy. Three electronic databases were searched for relevant articles from their inception to May 2021, including PubMed, Cochrane Library, and ScienceDirect. Pre- and post-test outcomes were adopted to estimate standardized mean difference with a 95% confidence interval for assessing the efficacy of yoga. Heterogeneity among articles was detected using I2 value. A total of 13 articles that contained 379 subjects were included for meta-analysis. No significant improvement in depression scores after practicing yoga was observed for women without depression (p = 0.09) but significant improvement was observed for women with depression (p = 0.001). Although significant improvement in anxiety scores after yoga was observed for women without depression (p = 0.02), the results of the sensitivity analysis were not consistent, while significant improvement in anxiety scores after yoga was also observed for women with depression (p &lt; 0.00001). The current evidence has suggested that yoga had significant improvement in depression and anxiety scores in pregnant women with depression. However, the level of evidence of this study was not high. More articles with high levels of evidence should be conducted to confirm our conclusion in the future

    Decreased Expression of Estrogen Receptors Is Associated with Tumorigenesis in Papillary Thyroid Carcinoma

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    Papillary thyroid carcinomas (PTC), which is derived from thyroid follicular cells, is the most commonly differentiated thyroid cancer with sex disparity. However, the role of estrogen receptors (ERs) in the pathogenesis of PTC remains unclear. The present study aimed to determine the association of ER mRNA expression levels with clinicopathologic features in PTC. To that aim, the mRNA levels of ESR1 (ER&alpha;66), ESR1 (ER&alpha;36), ESR2, and G-protein-coupled estrogen receptor 1 (GPER1) in snap-frozen tissue samples from PTCs and adjacent normal thyroid tissues were determined using quantitative reverse transcription polymerase chain reaction (RT-qPCR), and the correlation between ER mRNA expression levels and clinicopathologic features was analyzed. The expression of ER&alpha;66, ER&alpha;36, ER&beta;, and GPER1 was lower in PTC specimens than in adjacent normal thyroid tissues. Moreover, low GPER1 expression was associated with extrathyroidal extension. There was no obvious difference in expression of ERs between PTC specimens from male and female patients. In conclusion, our findings highlight the importance of ERs in PTC tumorigenesis

    Infectious complications in head and neck cancer patients treated with cetuximab: propensity score and instrumental variable analysis.

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    BACKGROUND: To compare the infection rates between cetuximab-treated patients with head and neck cancers (HNC) and untreated patients. METHODOLOGY: A national cohort of 1083 HNC patients identified in 2010 from the Taiwan National Health Insurance Research Database was established. After patients were followed for one year, propensity score analysis and instrumental variable analysis were performed to assess the association between cetuximab therapy and the infection rates. RESULTS: HNC patients receiving cetuximab (n = 158) were older, had lower SES, and resided more frequently in rural areas as compared to those without cetuximab therapy. 125 patients, 32 (20.3%) in the group using cetuximab and 93 (10.1%) in the group not using it presented infections. The propensity score analysis revealed a 2.3-fold (adjusted odds ratio [OR] = 2.27; 95% CI, 1.46-3.54; P = 0.001) increased risk for infection in HNC patients treated with cetuximab. However, using IVA, the average treatment effect of cetuximab was not statistically associated with increased risk of infection (OR, 0.87; 95% CI, 0.61-1.14). CONCLUSIONS: Cetuximab therapy was not statistically associated with infection rate in HNC patients. However, older HNC patients using cetuximab may incur up to 33% infection rate during one year. Particular attention should be given to older HNC patients treated with cetuximab

    miR-1246 as a therapeutic target in oral submucosa fibrosis pathogenesis

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    Background/purpose: Oral submucous fibrosis (OSF) is a precancerous condition of oral cancer with a complex etiology. Our previous work has demonstrated that non-coding RNA miR-1246 contributes to the cancer stemness of oral cancer. In the current study, we sought to investigate the effect of the inhibition of miR-1246 on the oral fibrogenesis. Methods: The expression levels of miR-1246 in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs) were examined by qRT-PCR. Collagen gel contraction and migration assays were conducted to evaluate the myofibroblast activities. The relationship between miR-1246 and type I collagen was assessed and the protein expression of type I collagen was determined by Western blot. Results: MiR-1246 expression was upregulated in both OSF specimen and fBMFs compared to the normal counterparts. Inhibition of miR-1246 successfully suppressed the myofibroblast activities, including collagen gel contractility and migration capacity. Moreover, the expression of miR-1246 was positively correlated with type I collagen and the expression of type I collagen was abrogated by repression of miR-1246. Conclusion: MiR-1246 is not only critical to the maintenance of oral stemness but also important to the activation of myofibroblasts. Our results showed that miR-1246 is positively associated with the type I collagen, which may be a downstream effector of miR-1246 and responsible for the fibrosis effect on fBMFs
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