| 1. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
|
|
| 2. |
- Chi, Kequn, et al.
(författare)
-
Large-scale nanostructured low-temperature solar selective absorber
- 2017
-
Ingår i: Optics Letters. - : Optical Society of America. - 0146-9592 .- 1539-4794. ; 42:10, s. 1891-1894
-
Tidskriftsartikel (refereegranskat)abstract
- A large-scale nanostructured low-temperature solar selective absorber is demonstrated experimentally. It consists of a silicon dioxide thin film coating on a rough refractory tantalum substrate, fabricated based simply on self-assembled, closely packed polystyrene nanospheres. Because of the strong light harvesting of the surface nanopatterns and constructive interference within the top silicon dioxide coating, our absorber has a much higher solar absorption (0.84) than its planar counterpart (0.78). Though its absorption is lower than that of commercial black paint with ultra-broad absorption, the greatly suppressed absorption/emission in the long range still enables a superior heat accumulation. The working temperature is as high as 196.3 degrees C under 7-sun solar illumination in ambient conditions-much higher than those achieved by the two comparables.
|
|
| 3. |
- Buck, M., et al.
(författare)
-
The LIVE program : Results of test L1 and joint analyses on transient molten pool thermal hydraulics
- 2010
-
Ingår i: Progress in nuclear energy (New series). - : Elsevier BV. - 0149-1970 .- 1878-4224. ; 52:1, s. 46-60
-
Tidskriftsartikel (refereegranskat)abstract
- The development of a corium pool in the lower head and its behaviour is still a critical issue. This concerns, in general, the understanding of a severe accident with core melting, its course, major critical phases and timing, and the influence of these processes on the accident progression as well as, in particular, the evaluation of in-vessel melt retention by external vessel flooding as an accident mitigation strategy. Previous studies were especially related to the in-vessel retention question and often just concentrated on the quasi-steady state behaviour of a large molten pool in the lower head, considered as a bounding configuration. However, non-feasibility of the in-vessel retention concept for high power density reactors and uncertainties e.g. due to layering effects even for low or medium power reactors, turns this to be insufficient. Rather, it is essential to consider the whole evolution of the accident, including e.g. formation and growth of the in-core melt pool, characteristics of corium arrival in the lower head, and molten pool behaviour after the debris re-melting. These phenomena have a strong impact on a potential termination of a severe accident. The general objective of the LIVE program at FZK is to study these phenomena resulting from core melting experimentally in large-scale 3D geometry and in supporting separate-effects tests, with emphasis on the transient behaviour. Up to now, several tests on molten pool behaviour have been performed within the LIVE experimental program with water and with non-eutectic melts (KNO3-NaNO3) as simulant fluids. The results of these experiments, performed in nearly adiabatic and in isothermal conditions, allow a direct comparison with findings obtained earlier in other experimental programs (SIMECO, ACOPO, BALI, etc.) and will be used for the assessment of the correlations derived for the molten pool behaviour. Complementary to other international programs with real corium melts, the results of the LIVE activities also provide data for a better understanding of in-core corium pool behaviour. The experimental results are being used for the development and validation of mechanistic models for the description of molten pool behaviour, In the present paper, a range of different models is used for post-test calculations and comparative analyses. This includes simplified, but fast running models implemented in the severe accident codes ASTEC and ATHLET-CD. Further, a computational tool developed at KTH (PECM model implemented in Fluent) is applied. These calculations are complemented by analyses with the CFD code CONV (thermal hydraulics of heterogeneous, viscous and heat-generating melts) which was developed at IBRAE (Nuclear Safety Institute of Russian Academy) within the RASPLAV project and was further improved within the ISTC 2936 Project.
|
|
| 4. |
- Chen, Yujie, et al.
(författare)
-
A gradient-distributed liquid-metal hydrogel capable of tunable actuation
- 2021
-
Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 421, s. 127762-
-
Tidskriftsartikel (refereegranskat)abstract
- Although thermoresponsive hydrogels have numerous applications that range from soft robots, biomedical engineering, and actuators to sensors for artificial muscles, the existing hydrogel actuators undergo only unidirectional deformation under a single thermal stimulus and suffer from slow actuation and unstable interfacial adhesion in multiple layers. Herein, hydrogels containing gradient-distributed polydopamine-coated eutectic gallium-indium (PDA-EGaIn) nanodroplets in a poly(N-isopropylacrylamide) (PNIPAM) matrix and thus featuring a gradient distribution of thermal conductivity and an increased barrier towards water loss are shown to be capable of a rapid and tuneable thermoresponse. Notably, whereas hydrogels with a low content of PDAEGaIn undergo rapid one-way bending under a single thermal (45 degrees C) stimulus, those with a high content of PDAEGaIn undergo sequential bidirectional (bending) actuation. The ability of these hydrogels to undergo fast and tuneable actuation under a single thermal stimulus makes them suitable for use in grab-release instruments and soft robots.
|
|
| 5. |
- Chen, Yujie, et al.
(författare)
-
Shape-Memory Polymeric Artificial Muscles : Mechanisms, Applications and Challenges
- 2020
-
Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 25:18
-
Forskningsöversikt (refereegranskat)abstract
- Shape-memory materials are smart materials that can remember an original shape and return to their unique state from a deformed secondary shape in the presence of an appropriate stimulus. This property allows these materials to be used as shape-memory artificial muscles, which form a subclass of artificial muscles. The shape-memory artificial muscles are fabricated from shape-memory polymers (SMPs) by twist insertion, shape fixation via T(m)or T-g, or by liquid crystal elastomers (LCEs). The prepared SMP artificial muscles can be used in a wide range of applications, from biomimetic and soft robotics to actuators, because they can be operated without sophisticated linkage design and can achieve complex final shapes. Recently, significant achievements have been made in fabrication, modelling, and manipulation of SMP-based artificial muscles. This paper presents a review of the recent progress in shape-memory polymer-based artificial muscles. Here we focus on the mechanisms of SMPs, applications of SMPs as artificial muscles, and the challenges they face concerning actuation. While shape-memory behavior has been demonstrated in several stimulated environments, our focus is on thermal-, photo-, and electrical-actuated SMP artificial muscles.
|
|
| 6. |
- Chen, Zhen, et al.
(författare)
-
Multifunctional conductive hydrogels and their applications as smart wearable devices
- 2021
-
Ingår i: Journal of materials chemistry. B. - : Royal Society of Chemistry (RSC). - 2050-750X .- 2050-7518. ; 9:11, s. 2561-2583
-
Forskningsöversikt (refereegranskat)abstract
- Recently, hydrogekbased conductive materials and their applications as smart wearable devices have been paid tremendous attention due to their high stretchability, flexibility, and excellent biocompatibility. Compared with single functional conductive hydrogels, multifunctional conductive hydrogels are more advantageous to match various demands for practical applications. This review focuses on multifunctional conductive hydrogels applied for smart wearable devices. Representative strategies for conduction of hydrogels are discussed firstly: (1) electronic conduction based on the conductive fillers and (2) ionic conduction based on charged ions. Then, the common and intensive research on multiple functionahties of conductive hydrogels, such as mechanical properties, conductive and sensory properties, anti-freezing and moisturizing properties, and adhesion and self-healing properties is presented. The applications of multifunctional conductive hydrogels such as in human motion sensors, sensory skins, and personal healthcare diagnosis are provided in the third part. Finally, we offer our perspective on open challenges and future areas of interest for multifunctional conductive hydrogels used as smart wearable devices.
|
|
| 7. |
|
|
| 8. |
- Ding, Lijie, et al.
(författare)
-
Smoking, heavy drinking, physical inactivity, and obesity among middle-aged and older adults in China : cross-sectional findings from the baseline survey of CHARLS 2011-2012.
- 2020
-
Ingår i: BMC Public Health. - : BioMed Central. - 1471-2458. ; 20:1
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Prevention and control of cardiometabolic conditions and cardiovascular disease (CVD) in China may contribute to sustainable CVD reduction globally, given the fact that one-fifth of the worldwide population is in China. Knowing the distribution of behavioral risk factors (e.g., smoking and physical inactivity), especially at a national level in China, would be extremely relevant to the field of public health and CVD prevention. The objectives of this study were to investigate the nationwide prevalence of obesity, smoking, heavy drinking, and physical inactivity in Chinese adults, and further explore whether cardiometabolic conditions would modify the distribution of behavioral risk factors.METHODS: This population-based study is based on the China Health and Retirement Longitudinal Study (2011-2012), including 17,302 adults (≥45 years, mean age 59.67 years, female 51.66%) from 25 provinces in China. Data on demographics, lifestyle factors, health status and history of diseases were collected via structured interviews and laboratory tests. Smoking, heavy drinking, obesity, and physical inactivity were defined following standard guidelines. We performed descriptive analysis and logistic regressions in this study.RESULTS: The overall prevalence of heavy drinking, obesity, current smoking, and physical inactivity among middle-aged and older adults was 7.23% (95% confidence interval 6.53-7.29%), 11.53% (10.43-12.62%), 27.46% (26.30-28.62%), and 44.06% (41.19-46.92%), respectively. The prevalence varied between rural and urban areas as well as among geographic areas, with higher prevalence in the Northern and Northeastern regions. Heavy drinking and obesity were significantly associated with incident hypertension, diabetes, and high cholesterol; while current smoking was significantly associated with incident hypertension. Compared with healthy individuals, participants who self-reported a diagnosis of hypertension, high cholesterol, or diabetes were less likely to smoke currently and drink alcohol heavily, but more likely to be physically inactive and obese.CONCLUSIONS: Among Chinese middle-aged and older adults, the prevalence of behavioral risk factors varies by geographic region. Further effort is required to improve physical activity and fitness for Chinese adults, especially those with cardiometabolic conditions.
|
|
| 9. |
- Hu, Xiaolong, et al.
(författare)
-
Timing properties of superconducting nanowire single-photon detectors
- 2019
-
Ingår i: Quantum Optics and Photon Counting 2019. - : SPIE - International Society for Optical Engineering. - 9781510627215
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we review theoretical and experimental research progress on timing properties of superconducting nanowire single-photon detectors, including six possible mechanisms that induce timing jitter and experiments towards ultra-low timing jitter.
|
|
| 10. |
- Jia, S., et al.
(författare)
-
A unified system with integrated generation of high-speed communication and high-resolution sensing signals based on THz photonics
- 2018
-
Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers Inc.. - 0733-8724 .- 1558-2213. ; 36:19, s. 4549-4556
-
Tidskriftsartikel (refereegranskat)abstract
- Multifunctional convergence is one of the key physical features in future generation networks and Internet of things architectures. In this paper, we propose and experimentally demonstrate a unified terahertz (THz) system operating in the 300 GHz band, with a potential of simultaneously enabling high-speed communication and high-resolution ranging over a common optical infrastructure. Both THz communication and THz sensing signals are generated based on THz photonics and cutting-edge terahertz transceiver technologies. In the experiment, 16-quadrature amplitude modulation modulated THz signal is generated by photo-mixing two free running lasers for the communication, and linear frequency modulated (LFM) THz pulses are generated based on optical interferometer-based frequency-to-time mapping (FTM) for sensing. The experimental results show that up to 56 Gbit/s net rate is successfully transmitted over a 2 m free-space line-of-sight link, and the THz LFM pulses with a time-bandwidth product of up to 207 are successfully generated, which is potentially able to enable a cm-scale range resolution. We also investigate the frequency multiplexing schemes for two signals by changing the channel gap at the transmitter side. To the best of our knowledge, such a system represents the first demonstration of integrated generation system in the THz region above 300 GHz, which has great potential in prospective applications of future converged networks.
|
|
