| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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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.
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| 2. |
- Fang, Aoqi, et al.
(författare)
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High Color Conversion Efficiency Realized in Graphene-Connected Nanorod Micro-LEDs Using Hybrid Ag Nanoparticles and Quantum Dots
- 2024
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Ingår i: Advanced Optical Materials. - 2195-1071. ; 12:19
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a uniform nanorod (NR) array is etched onto the surface of Micro-Light-Emitting-Diodes (µLEDs) and mix Ag nanoparticles (NPs) with QDs to fill the gaps between the nanorods. Simultaneously, the study utilizes graphene to connect individual nanorods and enhance current spreading. The nanorod array's structure significantly reduces the distance between the QDs and the quantum well (QW), reducing energy loss from the excitation light source through a non-radiative energy transfer (NRET) mechanism. Additionally, the Ag NPs function as localized surface plasmons (LSPs), further enhancing the CCE of QDs via the absorption resonance. In this study, the effects of two types of Ag NPs are compared with different absorption resonance peaks on device performance. The results demonstrate that Ag NPs with absorption resonance peaks matching the emission wavelength of QDs play a more crucial role in the system. This configuration achieves a CCE of 77.78% for µLEDs with nanorod arrays, operating at a current of 10 mA. Compared to the conventional µLED structure with QDs only on the surface, the proposed method improves the CCE of µLEDs by an impressive 86.5%. This outcome underscores the significant contribution of the NR structure and LSPs in enhancing the CCE of QD-µLEDs.
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| 3. |
- Jin, Ying-Hui, et al.
(författare)
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Chemoprophylaxis, diagnosis, treatments, and discharge management of COVID-19 : An evidence-based clinical practice guideline (updated version)
- 2020
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Ingår i: Military Medical Research. - : Springer Science and Business Media LLC. - 2054-9369. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of a rapidly spreading illness, coronavirus disease 2019 (COVID-19), affecting more than seventeen million people around the world. Diagnosis and treatment guidelines for clinicians caring for patients are needed. In the early stage, we have issued "A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus (2019-nCoV) infected pneumonia (standard version)"; now there are many direct evidences emerged and may change some of previous recommendations and it is ripe for develop an evidence-based guideline. We formed a working group of clinical experts and methodologists. The steering group members proposed 29 questions that are relevant to the management of COVID-19 covering the following areas: chemoprophylaxis, diagnosis, treatments, and discharge management. We searched the literature for direct evidence on the management of COVID-19, and assessed its certainty generated recommendations using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Recommendations were either strong or weak, or in the form of ungraded consensus-based statement. Finally, we issued 34 statements. Among them, 6 were strong recommendations for, 14 were weak recommendations for, 3 were weak recommendations against and 11 were ungraded consensus-based statement. They covered topics of chemoprophylaxis (including agents and Traditional Chinese Medicine (TCM) agents), diagnosis (including clinical manifestations, reverse transcription-polymerase chain reaction (RT-PCR), respiratory tract specimens, IgM and IgG antibody tests, chest computed tomography, chest x-ray, and CT features of asymptomatic infections), treatments (including lopinavir-ritonavir, umifenovir, favipiravir, interferon, remdesivir, combination of antiviral drugs, hydroxychloroquine/chloroquine, interleukin-6 inhibitors, interleukin-1 inhibitors, glucocorticoid, qingfei paidu decoction, lianhua qingwen granules/capsules, convalescent plasma, lung transplantation, invasive or noninvasive ventilation, and extracorporeal membrane oxygenation (ECMO)), and discharge management (including discharge criteria and management plan in patients whose RT-PCR retesting shows SARS-CoV-2 positive after discharge). We also created two figures of these recommendations for the implementation purpose. We hope these recommendations can help support healthcare workers caring for COVID-19 patients.
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| 4. |
- Qin, Tao, et al.
(författare)
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Efficient Synthesis of Angular Selective Surfaces Based on Accurate Equivalent Circuit Analysis
- 2023
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480. ; 71:6, s. 2625-2638
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Tidskriftsartikel (refereegranskat)abstract
- A new efficient synthesis method of angular selective surfaces (ASSs) based on the accurate equivalent circuit model is proposed. The angular dispersion of different components under oblique incidence is modeled by virtual lumped elements in the angular domain. The processes of obtaining the equivalent circuit for substrates, electrically small grids and patch arrays are presented in detail. The synthesized circuits are simple and accurate. Full-wave simulations are carried out to obtain the angular dispersion of different structures, and the calculated results are in good agreement with those of the equivalent circuit. A third-order ASS with bandpass response and a second-order ASS with a tunable bandwidth are given as design examples. The implemented second-order ASS shows the 0.33 to 0.52 tunable bandwidth in the angular domain. The transmission loss is better than 1.2 dB when the incidence angle is 65°-77°. The simulation results and calculated results are in good agreement with the measured results.
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| 5. |
- Li, Kai, et al.
(författare)
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Metal thermopile infrared detector with vertical graphene
- 2023
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Ingår i: Wuli Xuebao/Acta Physica Sinica. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 72:3
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Tidskriftsartikel (refereegranskat)abstract
- Thermopile infrared detector is a kind of detector device mainly composed of thermocouple as the basic unit. Because of its simple principle, no need of cooling equipment, and other advantages, it has been widely used in various fields of production and life. However, the absorption rates of the materials in conventional thermopile devices are poor, and the majority of them are incompatible with microfabrication methods. In this work, a metal thermopile infrared detector with vertical graphene (VG) is designed and fabricated. The VG is grown via plasma enhanced chemical vapor deposition, and retained at the device’s thermal ends to provide the thermopile IR detector’s wideband and high response characteristics. The detector achieves a room temperature responsivity reaching a value as high as 1.53 V/W at 792 nm, which can increase the response results about 28 times and reduce the response time to 0.8 ms compared with the thermopile detector without VG. After systematically measuring the response results, it is finally found that there are three main mechanisms responsible for the response on the composite device. The first one is the response generated by the metal thermopile itself alone. The second one is the response increased eventually by the contribution of VG covered at the metal thermal junction that expands the temperature difference. The last one is the response generated by the temperature gradient existing inside the VG on the surface of the device after the absorption of heat. The portion of each partial response mechanism in the total response is also analyzed, providing a new reference direction for analyzing the response generation mechanism of thermopile detectors with other absorbing materials. The process is compatible with the microfabrication, while the device performance is enhanced and suitable for mass production. Furthermore, by utilizing the surface plasmon resonance to combine VG with metal nanoparticles, the material’ s light absorption is found to be enhanced significantly under the same conditions, and the resulting thermal voltage can be increased to 6 times. The results indicate that VG promises to possess practical applications, in many fields such as photoelectric sensing and power production devices. This technology provides a new method to manufacture high-performance thermopile infrared detectors and other sensor devices.
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| 6. |
- Mei, Xueshuang, et al.
(författare)
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Vascular Supply of the Human Spiral Ganglion : Novel Three-Dimensional Analysis Using Synchrotron Phase-Contrast Imaging and Histology
- 2020
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Human spiral ganglion (HSG) cell bodies located in the bony cochlea depend on a rich vascular supply to maintain excitability. These neurons are targeted by cochlear implantation (CI) to treat deafness, and their viability is critical to ensure successful clinical outcomes. The blood supply of the HSG is difficult to study due to its helical structure and encasement in hard bone. The objective of this study was to present the first three-dimensional (3D) reconstruction and analysis of the HSG blood supply using synchrotron radiation phase-contrast imaging (SR-PCI) in combination with histological analyses of archival human cochlear sections. Twenty-six human temporal bones underwent SR-PCI. Data were processed using volume-rendering software, and a representative three-dimensional (3D) model was created to allow visualization of the vascular anatomy. Histologic analysis was used to verify the segmentations. Results revealed that the HSG is supplied by radial vascular twigs which are separate from the rest of the inner ear and encased in bone. Unlike with most organs, the arteries and veins in the human cochlea do not follow the same conduits. There is a dual venous outflow and a modiolar arterial supply. This organization may explain why the HSG may endure even in cases of advanced cochlear pathology.
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| 7. |
- Ntalla, Ioanna, et al.
(författare)
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Multi-ancestry GWAS of the electrocardiographic PR interval identifies 202 loci underlying cardiac conduction
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The electrocardiographic PR interval reflects atrioventricular conduction, and is associated with conduction abnormalities, pacemaker implantation, atrial fibrillation (AF), and cardiovascular mortality. Here we report a multi-ancestry (N=293,051) genome-wide association meta-analysis for the PR interval, discovering 202 loci of which 141 have not previously been reported. Variants at identified loci increase the percentage of heritability explained, from 33.5% to 62.6%. We observe enrichment for cardiac muscle developmental/contractile and cytoskeletal genes, highlighting key regulation processes for atrioventricular conduction. Additionally, 8 loci not previously reported harbor genes underlying inherited arrhythmic syndromes and/or cardiomyopathies suggesting a role for these genes in cardiovascular pathology in the general population. We show that polygenic predisposition to PR interval duration is an endophenotype for cardiovascular disease, including distal conduction disease, AF, and atrioventricular pre-excitation. These findings advance our understanding of the polygenic basis of cardiac conduction, and the genetic relationship between PR interval duration and cardiovascular disease. On the electrocardiogram, the PR interval reflects conduction from the atria to ventricles and also serves as risk indicator of cardiovascular morbidity and mortality. Here, the authors perform genome-wide meta-analyses for PR interval in multiple ancestries and identify 141 previously unreported genetic loci.
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| 8. |
- Surendran, Praveen, et al.
(författare)
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Discovery of rare variants associated with blood pressure regulation through meta-analysis of 1.3 million individuals
- 2020
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 52:12, s. 1314-1332
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Tidskriftsartikel (refereegranskat)abstract
- Genetic studies of blood pressure (BP) to date have mainly analyzed common variants (minor allele frequency > 0.05). In a meta-analysis of up to similar to 1.3 million participants, we discovered 106 new BP-associated genomic regions and 87 rare (minor allele frequency <= 0.01) variant BP associations (P < 5 x 10(-8)), of which 32 were in new BP-associated loci and 55 were independent BP-associated single-nucleotide variants within known BP-associated regions. Average effects of rare variants (44% coding) were similar to 8 times larger than common variant effects and indicate potential candidate causal genes at new and known loci (for example, GATA5 and PLCB3). BP-associated variants (including rare and common) were enriched in regions of active chromatin in fetal tissues, potentially linking fetal development with BP regulation in later life. Multivariable Mendelian randomization suggested possible inverse effects of elevated systolic and diastolic BP on large artery stroke. Our study demonstrates the utility of rare-variant analyses for identifying candidate genes and the results highlight potential therapeutic targets.
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| 9. |
- Tang, Peng Hao, et al.
(författare)
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A patterning technology of transfer-free graphene for transparent electrodes of near-ultraviolet light-emitting diodes
- 2024
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Ingår i: Journal of Materials Chemistry C. - 2050-7534 .- 2050-7526. ; 12:26, s. 9824-9833
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Tidskriftsartikel (refereegranskat)abstract
- Graphene is well known for its excellent physical and chemical properties and can be used in various fields. Its application technology has become an important direction of research. In this study, a patterning technology of transfer-free graphene is reported, and graphene transparent electrodes of near-ultraviolet light-emitting diodes (LEDs) are fabricated accordingly. In the scheme, Ni film plays the dual role of an etching mask and graphene growth catalyst, realizing the patterning growth of graphene. An SiO2 isolation layer is deposited between Ni and the substrate, avoiding the fusing of the substrate with Ni by the high temperature of graphene growth, which makes the method applicable to nominally any high temperature-compatible metal and semiconductor substrates. Both Ni and SiO2 are then removed, thus directly achieving a good contact between graphene and the substrate. The graphene transparent electrodes fabricated by this method greatly improves the performance of near-ultraviolet LEDs, which is even better than that of indium tin oxide (ITO) in the near-ultraviolet band based on the optical measurement results. This scheme avoids any possible damage and contamination of graphene in traditional transfer and lithography patterning processes, which is scalable and suitable for real applications.
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| 10. |
- Tang, Wanru, et al.
(författare)
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Drought variations in the southeastern Tibetan Plateau region since 1704 and their link to the Atlantic Multidecadal Oscillation
- 2023
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - 0031-0182. ; 630
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the long-term history of drought in the Tibetan Plateau region is important to improve understanding of drought frequency in response to future global warming. Although the Tibetan Plateau has become generally wetter recently, the southeastern part of the Tibetan Plateau has become drier since the 2000s. To place this drying trend in a historical context, we conducted tree-ring studies for Abies spectabilis and Tsuga dumosa at three sites in the southeastern Tibetan Plateau, and developed tree-ring width (TRW), earlywood width (EWW), and latewood width (LWW) chronologies to permit local drought reconstruction. Based on correlation between these tree-ring parameters and instrumental meteorological data, the EWW chronologies were identified as suitable variables for reconstructing the average April–July self-calibrating Palmer Drought Index (scPDSI). The reconstruction accounted for 45.86% of the variance in the instrumental record and allowed us to extend the drought record back to 1704 CE. Based on this new dataset, the driest interval was from 1907 to 1919 CE during which time agricultural production fell by about 70% according to written historical records, leading to severe famine. Our findings suggest that this early twentieth century drought was in phase with the previously known drought over the northern Daxing'an Mountains. However, the southeastern Tibetan Plateau drought occurred one decade earlier than the known widespread drought event in North China during the 1920s–1930s. We show that this spatial drought pattern may have been modulated by the Atlantic Multidecadal Oscillation.
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