476 research outputs found
Double resonant absorption measurement of acetylene symmetric vibrational states probed with cavity ring down spectroscopy
A novel mid-infrared/near-infrared double resonant absorption setup for
studying infrared-inactive vibrational states is presented. A strong
vibrational transition in the mid-infrared region is excited using an idler
beam from a singly resonant continuous-wave optical parametric oscillator, to
populate an intermediate vibrational state. High output power of the optical
parametric oscillator and the strength of the mid-infrared transition result in
efficient population transfer to the intermediate state, which allows measuring
secondary transitions from this state with a high signal-to-noise ratio. A
secondary, near-infrared transition from the intermediate state is probed using
cavity ring down spectroscopy, which provides high sensitivity in this
wavelength region. Due to the narrow linewidths of the excitation sources, the
rovibrational lines of the secondary transition are measured with sub-Doppler
resolution. The setup is used to access a previously unreported symmetric
vibrational state of acetylene, in the
normal mode notation. Single-photon transitions to this state from the
vibrational ground state are forbidden. Ten lines of the newly measured state
are observed and fitted with the linear least-squares method to extract the
band parameters. The vibrational term value was measured to be at 9775.0018(45)
, the rotational parameter was 1.162222 ,
and the quartic centrifugal distortion parameter was 3.998(62), where the numbers in the parenthesis are one-standard
errors in the least significant digits
Origin of calcite in the glacigenic Virttaankangas complex
Groundwaters of the glacigenic Virttaankangas complex in southern Finland are characterized by high pH values ranging up to 9.5. These values are significantly higher than those observed in silicate-rich shallow groundwater formations in crystalline bedrock areas. TheVirttaankangas sediments were discovered to contain small amounts of fine grained, dispersed calcite, which has a high tendency to increase the pH of local groundwaters. The primary goal of this study was to determine the mode of occurrence of calcite and to identifyits sources. The mineralogy of the glacigenic Virttaankangas complex was studied using material from 21 sediment drill cores. Fine-grained calcite is present in trace amounts (<< 1.4 %) in the glaciofluvial and glaciolacustrine depositional units of the Virttaankangas complex. The topmost littoral sands were practically devoid of calcite. The isotope records of carbon and oxygen, the angular morphology of the grains and the uniform dispersion of calcite in the complex suggest a clastic origin for calcite, with no evidence for in-situ precipitation. In order to constrain the source of calcite, the isotopic composition of carbon and oxygen in five calcite samples was compared to the isotopic data from five carbonate rock erratics and eight crystalline bedrock samples from the region. Based on carbon and oxygen isotope ratios and chemical compositions, the dispersed calcite grains of the Virttaankangas complex appear to have been derived from the Mesoproterozoic Satakunta Formation, some 30 km NW from the Virttaankangas area. In sandstone, calcite is predominantly present as diagenetic cement in grain interspaces, concretions and interlayers. The source of detrital calcite was unexpected, as prior to this study the Satakunta sandstone hasnot been known to contain calcite
Efficacy of salbutamol via Easyhaler®unaffected by low inspiratory flow
AbstractThe fine particle dose delivered via dry powder inhalers (DPIs) is often affected by the inspiratory flow rate generated during inhalation. This has clinical implications, since the fine particle dose determines the amount of drug reaching the lungs. With Easyhaler®DPI the fine particle dose remains relatively constant over the range of inspiratory flow rates from 30–60 l min−1. The aim of this study was to confirm that clinical efficacy is maintained even at low flow rates by comparing the bronchodilating effect of salbutamol (100 μ g) delivered via Easyhaler®at a target inspiratory flow of 30 l min−1with the same dose of salbutamol via pressurised metered-dose inhaler (pMDI) plus spacer.This was a double-blind, randomized, cross-over study with double-dummy technique. Twenty-one paediatric and adult asthmatic patients completed the study, which was conducted over 2 study days. The main outcome parameter was forced expiratory volume in 1 sec (FEV1). The patients were trained to generate a low peak inspiratory flow rate (PIFR) of 30 l min−1, and the actual PIFR through Easyhaler®was recorded.The average PIFR through Easyhaler®was 28·7 l min−1. The difference in the maximum value of FEV1(FEV1max) between the treatments after drug inhalation was 0·01 l. The mean of FEV1maxwas 2·67 l after pMDI plus spacer compared to 2·69 l after Easyhaler®. Improvements in FEV1were clinically significant. No significant differences between treatments were found.A reasonably low inspiratory flow rate through Easyhaler®produces an equivalent improvement in lung function to a correctly used pMDI plus spacer. Hence, Easyhaler®can be used with confidence in patients who may have difficulty in generating a high inspiratory flow rate, such as children and the elderly
Cantilever-Enhanced Photoacoustic Spectroscopy of Radioactive Methane
We report the first high-resolution spectroscopy study of radiocarbon methane, 14CH4. Several absorption lines of the fundamental vibrational band v3 were measured using a continuous-wave mid-infrared optical parametric oscillator with cantilever-enhanced photoacoustic spectroscopy. © 2020 OSA.Peer reviewe
Aggressive pituitary adenomas occurring in young patients in a large Polynesian kindred with a germline R271W mutation in the AIP gene.
peer reviewedOBJECTIVE: Mutations in the aryl hydrocarbon receptor-interacting protein (AIP) were recently shown to confer a pituitary adenoma predisposition in patients with familial isolated pituitary adenomas (FIPA). We report a large Samoan FIPA kindred from Australia/New Zealand with an R271W mutation that was associated with aggressive pituitary tumors. DESIGN AND METHODS: Case series with germline screening of AIP and haplotype analyses among R271W families. RESULTS: This previously unreported kindred consisted of three affected individuals that either presented with or had first symptoms of a pituitary macroadenoma in late childhood or adolescence. The index case, a 15-year-old male with incipient gigantism and his maternal aunt, had somatotropinomas, and the maternal uncle of the index case had a prolactinoma. All tumors were large (15, 40, and 60 mm maximum diameter) and two required transcranial surgery and radiotherapy. All three affected subjects and ten other unaffected relatives were found to be positive for a germline R271W AIP mutation. Comparison of the single nucleotide polymorphism patterns among this family and two previously reported European FIPA families with the same R271W mutation demonstrated no common ancestry. CONCLUSIONS: This kindred exemplifies the aggressive features of pituitary adenomas associated with AIP mutations, while genetic analyses among three R271W FIPA families indicate that R271W represents a mutational hotspot that should be studied further in functional studies
GATA4-targeted compound exhibits cardioprotective actions against doxorubicin-induced toxicity in vitro and in vivo : establishment of a chronic cardiotoxicity model using human iPSC-derived cardiomyocytes
Doxorubicin is a widely used anticancer drug that causes dose-related cardiotoxicity. The exact mechanisms of doxorubicin toxicity are still unclear, partly because most in vitro studies have evaluated the effects of short-term high-dose doxorubicin treatments. Here, we developed an in vitro model of long-term low-dose administration of doxorubicin utilizing human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Moreover, given that current strategies for prevention and management of doxorubicin-induced cardiotoxicity fail to prevent cancer patients developing heart failure, we also investigated whether the GATA4-targeted compound 3i-1000 has cardioprotective potential against doxorubicin toxicity both in vitro and in vivo. The final doxorubicin concentration used in the chronic toxicity model in vitro was chosen based on cell viability data evaluation. Exposure to doxorubicin at the concentrations of 1-3 mu M markedly reduced (60%) hiPSC-CM viability already within 48 h, while a 14-day treatment with 100 nM doxorubicin concentration induced only a modest 26% reduction in hiPCS-CM viability. Doxorubicin treatment also decreased DNA content in hiPSC-CMs. Interestingly, the compound 3i-1000 attenuated doxorubicin-induced increase in pro-B-type natriuretic peptide (proBNP) expression and caspase-3/7 activation in hiPSC-CMs. Moreover, treatment with 3i-1000 for 2 weeks (30 mg/kg/day, i.p.) inhibited doxorubicin cardiotoxicity by restoring left ventricular ejection fraction and fractional shortening in chronic in vivo rat model. In conclusion, the results demonstrate that long-term exposure of hiPSC-CMs can be utilized as an in vitro model of delayed doxorubicin-induced toxicity and provide in vitro and in vivo evidence that targeting GATA4 may be an effective strategy to counteract doxorubicin-induced cardiotoxicity.Peer reviewe
Toxicity profiling of cardiac transcription factor-targeted compounds in various cardiac and stem cell types reveals cell type-and compound-dependent toxicity
Rapid and accurate processing of multiple objects in briefly presented scenes
Humans can detect multiple objects in briefly presented natural visual scenes, but the mechanisms through which the objects are segmented from the background and consciously accessed remain open. By asking participants to report how many humans natural photos presented for 50 ms contain, we show that up to three items can be rapidly enumerated from natural scenes without compromising speed or accuracy. In contrast to standard parallel and serial models of object selection, our results revealed that the participants were fastest in enumerating two objects; even enumerating one single item required additional processing time. Also enumeration accuracy slightly increased in the subitizing range as number increased. Our results suggest that the visual system is tuned to process multiple items, which may underlie spatial and numerical cognition, and be beneficial in real-world situations that often require dealing with more than one object at a time
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