Depth-of-interaction (DOI) capability is important for achieving high spatial resolution and sensitivity in dedicated organ and small animal positron emission tomography (PET) scanners. The ...dual-ended readout is one of the common methods that can achieve good DOI resolution. The aim of this study is to evaluate a dual-ended readout detector based on silicon photomultiplier (SiPM) and TOFPET2 application-specific integrated circuit (ASIC). The detector is based on 4 Formula: see text 4 lutetium-yttrium oxyorthosilicate (LYSO) units, each unit contained 6 Formula: see text 6 LYSO crystals, and the crystal size was 1 Formula: see text 1 Formula: see text 20 mm
. The four lateral surfaces of LYSO crystals were mechanically ground to W14 (surface roughness 10-14 Formula: see textm), and the two ended surfaces were polished (surface roughness <0.5 Formula: see textm). The reflector was Toray Lumirror E60, and the packing fraction of the LYSO block was 86.5%. Each LYSO unit was read out from both ends with two Hamamatsu S13361-3050AE-08 SiPM arrays. The analog output signals of SiPM were digitized by PETsys TOFPET2 ASIC and acquired by PETsys SiPM Readout System. The ASIC and SiPM were cooled by a fan and a Peltier element. To investigate the crystal resolvability, different light guide thicknesses including 0.8, 1, 1.2 and 2 mm were tested. The light guide was made of optical glass (H-K9L-Foctek Photoincs), and the size and refractive index were 6.45 Formula: see text 6.45 mm
and 1.53 (at 420 nm), respectively. To characterize the detector performance at different depths, another 1 Formula: see text 25.8 Formula: see text 20 mm
single LYSO slab was used. Data were acquired at 10 depths (1, 3, …, 19 mm), and each depth had a 10 min acquisition time and about 40 thousand coincidence events. During the experiment, the SiPM temperature was controlled as 27.6 Formula: see text 0.4 °C. The results showed that the 1.2 mm light guide offered the best crystal resolvability. The energy, coincidence time, and DOI resolution full-width at half-maximum of the detector were characterized as 15.66% Formula: see text 0.66%, 602.98 Formula: see text 10.58 ps, and 2.33 Formula: see text 0.07 mm, respectively. The good DOI resolution indicates the potential of utilizing the detector for high-resolution PET applications.
Separation of scintillation and Cherenkov lights in linear alkyl benzene Li, Mohan; Guo, Ziyi; Yeh, Minfang ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2016, Letnik:
830, Številka:
C
Journal Article
Recenzirano
Odprti dostop
To separate scintillation and Cherenkov lights in water-based liquid scintillator detectors is a desired feature for future neutrino and proton decay experiments. Linear alkyl benzene (LAB) is one ...important ingredient of a water-based liquid scintillator currently under development. In this paper we report on the separation of scintillation and Cherenkov lights observed in an LAB sample. The rise and decay times of the scintillation light are measured to be (7.7±3.0)ns and (36.6±2.4)ns, respectively, while the full width −3σ, 3σ of the Cherenkov light is 12ns and is dominated by the time resolution of the photomultiplier tubes. The scintillation light yield was measured to be (1.01±0.12)×103photons/MeV.
In sensor-based systems, the data of an object is often provided by multiple sources. Since the data quality of these sources might be different, when querying the observations, it is necessary to ...carefully select the sources to make sure that high quality data is accessed. A solution is to perform a quality evaluation in the cloud and select a set of high-quality, low-cost data sources (i.e., sensors or small sensor networks) that can answer queries. This paper studies the problem of min-cost quality-aware query which aims to find high quality results from multi-sources with the minimized cost. The measurement of the query results is provided, and two methods for answering min-cost quality-aware query are proposed. How to get a reasonable parameter setting is also discussed. Experiments on real-life data verify that the proposed techniques are efficient and effective.
To investigate the correlation of air-conduction thresholds between automated audiometry in a non-isolated environment and manual audiometry in participants with normal hearing and different degrees ...of hearing loss.
Eighty-three participants aged 11-88 years old underwent automated pure-tone audiometry in a non-acoustically isolated environment, and the results were compared with those of manual pure-tone audiometry performed in a standard acoustically isolated booth, with the order of testing randomised. Six frequencies of 250, 500, 1,000, 2000, 4,000 and 8,000 Hz were tested.
All 166 ears were completed and 996 valid hearing threshold data were obtained, with 28 data exceeding the 95% confidence interval in the Bland-Altman plot, accounting for 2.81% of all data. The means and standard deviations of the differences for the six frequencies from 250 to 8,000 Hz were, respectively, 0.63 ± 5.31, 0.69 ± 4.50, 0.45 ± 4.99, 0.3 ± 6.2, -0.15 ± 4.8, and 0.21 ± 4.97 dB. The correlation coefficients of the two test results for normal hearing, mild, moderate, severe and above hearing loss groups were 0.95, 0.92, 0.97, and 0.96, respectively. The correlation coefficient of the automated and manual audiometry thresholds for the age groups under 40 years, 40-60 years, and 60 years above, were 0.98, 0.97 and 0.97, respectively, with all being statistically significant (
< 0.01). The response time of the three age groups were 791 ± 181 ms, 900 ± 190 ms and 1,063 ± 332 ms, respectively, and there was a significant difference between the groups under 40 years and over 60 years.
There was good consistency between automated pure-tone audiometry in a non-acoustically isolated environment and manual pure-tone audiometry in participants with different hearing levels and different age groups.
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•An efficient melanin-targeted ultrasonic-assisted bleaching strategy is designed for yak hair.•Ultrasound enhances the WI of yak hair up to 44.6% than those without ultrasound.•Both ...tensile strength and elongation varied within 15% after ultrasonic bleaching.•Ultrasound increases 94% of HO which is the main oxidative bleaching species.•A theoretical highest WI of 52.4 is achieved on yak hair under optimal condition.
Promoting processing efficiency and taking advantage of agricultural by-products are two promising ways to achieve sustainable textile industry. This study presents a customized efficient ultrasonic-assisted bleaching strategy for yak hair – a widely existing but underexploited secondary dark shade fibre from yak. A melanin-targeted Fenton oxidation process is established which involves three phases, i.e., (I) incorporation of Fe2+ ions with melanin, (II) catalytic oxidative bleaching using hydrogen peroxide (H2O2), and (III) reductive cleansing. The bleaching efficacy, dyeing performance and tensile property of yak hair treated with and without ultrasound were explored and compared. Further, the ultrasonic bleaching mechanism in terms of the catalytic effect of Fe2+ ions, the promotion of H2O2 decomposition, removal of melanin granule from yak hair, were demonstrated. Finally, the main effects and interactions of parameters in phase II, and optimal condition were obtained through mathematical modelling based on a central composite design (CCD). Results reveal that ultrasonic bleaching dramatically enhances the whiteness index (WI) of yak hair from 11 to 45 which is 44.6% higher than those bleached without ultrasound, and also promotes the uptake of acid dyes. There is only 15% tensile strength loss and 14% elongation increment of yak hair after ultrasonic bleaching, rising from a slight damage of cuticle layer and cleavage of disulfide bonds, respectively. In the study of bleaching mechanism, Fe2+ ion is confirmed to improve the H2O2 decomposition rate by 20.9% which further runs up to 35.9% after introducing ultrasound. Ultrasound increases the concentration of hydroxyl radicals (HO) by 94% which are the main oxidative species participating in bleaching confirmed by HO scavenging experiment. The porous structure was observed on the cross section of yak hair stemming from the removal of melanin granules contributed by the cleaning action of ultrasound. A theoretical highest WI of 52.4 can be achieved under an optimal condition based on the CCD study. In general, the proposed melanin-targeted bleaching strategy for yak hair that integrates ultrasonic technology and Fenton reaction, is beneficial to the development of sustainable textile industry from material and processing perspectives.
This interdisciplinary study aims to investigate the younger generations of tourists' (That is, those who were born either in the 1980s or 1990s) photographic performances other than taking a selfie. ...In order to achieve this aim, the innovative research method of visual autoethnography is employed. Based upon the empirical research undertaken amongst Chinese younger tourists in the UK, this study unpacks that, for Chinese younger tourists, who appear to be becoming postmodern, the smartphone has potentially become a "toy" and photo-taking a means to fulfilling their insatiable desire for hedonism in travel. Notably, in the fieldwork, the Chinese respondents were identified to play an interactive game of photo-taking and photo-sharing, casting the focus of their gaze on each other and engaging with the destination in the child-like fashion. In so doing, the playful, immediate, spontaneous, simultaneous and sociable characteristics of tourist photography in general might have been reinforced further. Also, the life-span for smartphone-based digital snapshots is found to have become much shorter, and smartphone-based digital snapshots have potentially become a kind of artifacts more suitable for instantaneous consumption than a part and parcel of representation files useful to stage myths for tourist places.
Triple-negative breast cancer (TNBC) has the characteristics of a complex molecular landscape, aggressive or high proliferation leading to poor prognosis, and behavioral heterogeneity. The purpose of ...the present study was to determine the spatiotemporal expression of α-smooth muscle actin (α-SMA)-positive cancer-associated fibroblasts (CAFs) at histological level in 4T1 tumors and to predict the sensitivity to 138 drugs in patients with TNBC according to α-SMA expression. The quantitative results of fibrosis showed that the volume of 4T1 tumors correlated positively with the area of tumor fibrosis. Furthermore, we divided 4T1 tumors according to the degree of fibrosis and characterized the molecular characteristics of the four regions. Finally, the difference in the signaling pathways and sensitivity to 138 drugs was analyzed in patients with TNBC according to α-SMA expression combined with The Cancer Genome Atlas (TCGA) database. The myogenesis, TGF-β, and Notch signaling pathways were upregulated and the patients with TNBC were significantly differentially sensitive to 25 drugs. The results of in vivo experiments showed that the inhibitory effect of embelin on 4T1 tumors with high α-SMA expression was greater than that on 4TO7 tumors with low α-SMA expression. At the same time, embelin significantly decreased α-SMA and PDGFRA expression in 4T1 tumors compared with the control group. Our findings add to understanding of CAF distribution in the 4T1 tumor microenvironment and its possible role in treating cancer.
•The quantitative results of fibrosis showed that the volume of 4T1 tumors correlated positively with the tumor fibrosis.•4T1 tumors were divided in the degree of fibrosis and characterized the molecular characteristics of the four regions.•The myogenesis, TGF-β, and Notch signaling pathways were upregulated in TNBC patients who enriched CAFs in tumors.•Patients with TNBC were significantly differentially sensitive to 25 drugs.
Electronic patches, based on various mechanisms, allow continuous and noninvasive monitoring of biomolecules on the skin surface. However, to date, such devices are unable to sense biomolecules in ...deep tissues, which have a stronger and faster correlation with the human physiological status than those on the skin surface. Here, we demonstrate a photoacoustic patch for three-dimensional (3D) mapping of hemoglobin in deep tissues. This photoacoustic patch integrates an array of ultrasonic transducers and vertical-cavity surface-emitting laser (VCSEL) diodes on a common soft substrate. The high-power VCSEL diodes can generate laser pulses that penetrate >2 cm into biological tissues and activate hemoglobin molecules to generate acoustic waves, which can be collected by the transducers for 3D imaging of the hemoglobin with a high spatial resolution. Additionally, the photoacoustic signal amplitude and temperature have a linear relationship, which allows 3D mapping of core temperatures with high accuracy and fast response. With access to biomolecules in deep tissues, this technology adds unprecedented capabilities to wearable electronics and thus holds significant implications for various applications in both basic research and clinical practice.
Uveitis is a disease resulting in the inflammation of uveal tracts, but the factors resulting in uveitis is still obscure. Previous studies have shown that miR-379-5p was involved in the pathogenesis ...of several diseases, however, the role and regulatory mechanism of miR-379-5p in uveitis were unclear. In our study, we established experimental autoimmune uveitis (EAU) mouse models to explore the role of miR-379-5p in uveitis. RT-qPCR identified that miR-379-5p level was increased in serum of EAU mice. In mechanism, SEMA3A 3'UTR was proven to be directly targeted by miR-379-5p and SEMA3A expression was negatively regulated by miR-379-5p in CD4
+
T cells. Moreover, ELISA analysis revealed that knockdown of miR-379-5p suppressed the production of inflammation cytokines including IL-17, TNF-α and IL-β in vitro. These results were reversed by SEMA3A overexpression. In addition, the reduction of Th17 cells under miR-379-5p inhibitor was neutralised by SEMA3A knockdown in vitro. Furthermore, we demonstrated that knockdown of miR-379-5p significantly reversed the increased clinical scores and inflammatory response resulting from EAU treatment and this effect was further countervailed by SEMA3A silencing. Our study suggested that miR-379-5p aggravated uveitis in EAU mice via the regulation of SEMA3A, which may provide a novel insight for uveitis treatment.
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