| 1. |
-
- 2019
-
Tidskriftsartikel (refereegranskat)
|
|
| 2. |
|
|
| 3. |
- Luo, Yifei, et al.
(författare)
-
Technology Roadmap for Flexible Sensors
- 2023
-
Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
-
Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
|
|
| 4. |
- Birney, Ewan, et al.
(författare)
-
Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project
- 2007
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7146, s. 799-816
-
Tidskriftsartikel (refereegranskat)abstract
- We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.
|
|
| 5. |
- Fang, Chao, 1991, et al.
(författare)
-
HARQ in Poisson Point Process-based Heterogeneous Networks
- 2015
-
Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. - 9781479980888 ; 2015
-
Konferensbidrag (refereegranskat)abstract
- Hybrid automatic repeat request (HARQ) plays animportant role in improving the transmission efficiency and the robustness of wireless networks. Considering K-tier heterogeneous networks (HetNets) and modelling the locations of the base stations (BSs) as a homogeneous Poisson point process (PPP), this paper investigates the performance of HetNets implementing HARQ. We give closed-form expressions for the coverage probability and the per-user throughput with HARQ and show that using HARQ can indeed improve the coverage probability. However, depending on the channel conditions, the per-userthroughput of the HetNets may decrease by the implementation of HARQ. Furthermore, we show that the small cell density has negligible effect on the coverage probability and per-user throughput, and the per-user throughput may increase with the small cell path loss.
|
|
| 6. |
- Jiang, Jingting, et al.
(författare)
-
Clinical Application of Determining Serum AFP-IgM Complexes for Diagnosis of Small Hepatocellular Carcinoma.
- 2011
-
Ingår i: Anticancer research. - 1791-7530. ; 31:2, s. 687-691
-
Tidskriftsartikel (refereegranskat)abstract
- Diagnosis of primary hepatocellular carcinoma (HCC) at early stages has obviously been improved since determination of serum levels of free alpha-fetoprotein (AFP) was implemented. AFP has been considered as the standard tumor marker of primary HCC, although certain patients have very low serum free AFP levels. In the present study, clinical application of measuring serum AFP-IgM immune complexes compared to the serum free AFP was evaluated for diagnosis of small HCC. One hundred and three healthy controls, 74 patients with primary HCC, 27 patients with liver cirrhosis and 63 patients with chronic hepatitis were included in the present study. Serum levels of AFP-IgM immune complexes and free AFP were determined by ELISA and electrochemiluminescence, respectively. The best cut-off values of AFP-IgM immune complexes and free AFP for the diagnosis of primary HCC were 300 AU/ml and 10 μg/l, respectively, according to the area under the curve (AUC). At these cut-off values, the sensitivities of AFP-IgM and AFP for HCC were 64.9% and 79.7%, respectively, with specificities of 75.6% and 80.3%, respectively. Combining positivity for both tumor markers, the specificity and accuracy of diagnosis of HCC were 89.1% and 79.0%, respectively. Moreover, when the diameter of the tumor was ≤3 cm (being considered as small HCC), the sensitivity and specificity were 100.0% and 75.3%, respectively. There was no significant correlation between AFP-IgM level, patient sex or age (p>0.05). The ROC area was significantly different between AFP-IgM and AFP (Z=2.19, p=0.0286). In addition, the serum AFP-IgM levels were significantly higher in the patients with tumor diameter ≤3 cm (1090.4±571.8 AU/ml) than in the patients with tumor diameter >3 cm (604.9±749.9 AU/ml). It is concluded that determining serum levels of both AFP-IgM immune complex and AFP may have potential benefit for the diagnosis of small HCC.
|
|
| 7. |
- Lightowler, Molly, et al.
(författare)
-
Phase identification and discovery of an elusive polymorph of drug-polymer inclusion complex using automated 3D electron diffraction
- 2024
-
Ingår i: Angewandte Chemie International Edition. - 1433-7851 .- 1521-3773. ; 63:16
-
Tidskriftsartikel (refereegranskat)abstract
- 3D electron diffraction (3D ED) has shown great potential in crystal structure determination in materials, small organic molecules, and macromolecules. In this work, an automated, low-dose and low-bias 3D ED protocol has been implemented to identify six phases from a multiple-phase melt-crystallisation product of an active pharmaceutical ingredient, griseofulvin (GSF). Batch data collection under low-dose conditions using a widely available commercial software was combined with automated data analysis to collect and process over 230 datasets in three days. Accurate unit cell parameters obtained from 3D ED data allowed direct phase identification of GSF Forms III, I and the known GSF inclusion complex (IC) with polyethylene glycol (PEG) (GSF-PEG IC-I), as well as three minor phases, namely GSF Forms II, V and an elusive new phase, GSF-PEG IC-II. Their structures were then directly determined by 3D ED. Furthermore, we reveal how the stabilities of the two GSF-PEG IC polymorphs are closely related to their crystal structures. These results demonstrate the power of automated 3D ED for accurate phase identification and direct structure determination of complex, beam-sensitive crystallisation products, which is significant for drug development where solid form screening is crucial for the overall efficacy of the drug product.
|
|
| 8. |
- Wei, Ting, et al.
(författare)
-
Developed and developing world responsibilities for historical climate change and CO2 mitigation
- 2012
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:32, s. 12911-12915
-
Tidskriftsartikel (refereegranskat)abstract
- At the United Nations Framework Convention on Climate Change Conference in Cancun, in November 2010, the Heads of State reached an agreement on the aim of limiting the global temperature rise to 2 degrees C relative to preindustrial levels. They recognized that long-term future warming is primarily constrained by cumulative anthropogenic greenhouse gas emissions, that deep cuts in global emissions are required, and that action based on equity must be taken to meet this objective. However, negotiations on emission reduction among countries are increasingly fraught with difficulty, partly because of arguments about the responsibility for the ongoing temperature rise. Simulations with two earth-system models (NCAR/CESM and BNU-ESM) demonstrate that developed countries had contributed about 60-80%, developing countries about 20-40%, to the global temperature rise, upper ocean warming, and sea-ice reduction by 2005. Enacting pledges made at Cancun with continuation to 2100 leads to a reduction in global temperature rise relative to business as usual with a 1/3-2/3 (CESM 33-67%, BNU-ESM 35-65%) contribution from developed and developing countries, respectively. To prevent a temperature rise by 2 degrees C or more in 2100, it is necessary to fill the gap with more ambitious mitigation efforts.
|
|
| 9. |
- Yuan, Shuai, et al.
(författare)
-
[Ti8Zr2O12(COO)(16)] Cluster : An Ideal Inorganic Building Unit for Photoactive Metal-Organic Frameworks
- 2018
-
Ingår i: Acs Central Science. - : American Chemical Society (ACS). - 2374-7943 .- 2374-7951. ; 4:1, s. 105-111
-
Tidskriftsartikel (refereegranskat)abstract
- Metal-organic frameworks (MOFs) based on Ti-oxo clusters (Ti-MOFs) represent a naturally self-assembled superlattice of TiO2 nanoparticles separated by designable organic linkers as antenna chromophores, epitomizing a promising platform for solar energy conversion. However, despite the vast, diverse, and well-developed Ti-cluster chemistry, only a scarce number of Ti-MOFs have been documented. The synthetic conditions of most Ti-based clusters are incompatible with those required for MOF crystallization, which has severely limited the development of Ti-MOFs. This challenge has been met herein by the discovery of the [Ti8Zr2O12(COO)(16)] cluster as a nearly ideal building unit for photoactive MOFs. A family of isoreticular photoactive MOFs were assembled, and their orbital alignments were fine-tuned by rational functionalization of organic linkers under computational guidance. These MOFs demonstrate high porosity, excellent chemical stability, tunable photoresponse, and good activity toward photocatalytic hydrogen evolution reactions. The discovery of the [Ti8Zr2O12(COO)(16)] cluster and the facile construction of photoactive MOFs from this cluster shall pave the way for the development of future Ti-MOF-based photocatalysts. GRAPHICS
|
|
| 10. |
- Zhao, Yunlong, et al.
(författare)
-
Stable Alkali Metal Ion Intercalation Compounds as Optimized Metal Oxide Nanowire Cathodes for Lithium Batteries
- 2015
-
Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 15:3, s. 2180-2185
-
Tidskriftsartikel (refereegranskat)abstract
- Intercalation of ions in electrode materials has been explored to improve the rate capability in lithium batteries and supercapacitors, due to the enhanced diffusion of Li+ or electrolyte cations. Here, we describe a synergistic effect between crystal structure and intercalated ion by experimental characterization and ab initio calculations, based on more than 20 nanomaterials: five typical cathode materials together with their alkali metal ion intercalation compounds A-M-O (A = Li, Na, K, Rb; M = V, Mo, Co, Mn, Fe-P). Our focus on nanowires is motivated by general enhancements afforded by nanoscale structures that better sustain lattice distortions associated with charge/discharge cycles. We show that preintercalation of alkali metal ions in V-O and Mo-O yields substantial improvement in the Li ion charge/discharge cycling and rate, compared to A-Co-O, A-Mn-O, and A-Fe-P-O. Diffraction and modeling studies reveal that preintercalation with K and Rb ions yields a more stable interlayer expansion, which prevents destructive collapse of layers and allow Li ions to diffuse more freely. This study demonstrates that appropriate alkali metal ion intercalation in admissible structure can overcome the limitation of cyclability as well as rate capability of cathode materials, besides, the preintercalation strategy provides an effective method to enlarge diffusion channel at the technical level, and more generally, it suggests that the optimized design of stable intercalation compounds could lead to substantial improvements for applications in energy storage.
|
|
| 11. |
- Bengtsson, Viktor E. G., 1989-
(författare)
-
Crystal Structure Determination by 3D Electron Diffraction — New Software for Facilitating Data Processing
- 2022
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Three-Dimensional Electron Diffraction (3DED) is a useful technique for determining crystal structures from very small crystals (hundreds of \si{\nano\meter} or less). Examples of such crystals are zeolites, metal-organic frameworks (MOFs), pharmaceuticals, and proteins. Knowledge of the structure is useful for understanding and potentially changing how the material or substance functions. This thesis includes the structure determination of the MOFs CAU-42 and CAU-45 as well as the development of the software \emph{Scipion-ED} in response to challenges during the processing of 3DED data from the two MOFs. Both MOFs displayed correlated disorder, where disorder in one part of the structure influences the configuration of disorder in nearby parts. The influence of the solvent during synthesis on the final structured is also discussed. The development and design of the software \emph{Scipion-ED} is described. It is a graphical user interface based on \emph{scipion-pyworkflow} for workflow-centric data processing. The described implementation includes the foundation for using \emph{Scipion} to process 3DED data, as well as a plugin for processing with \emph{DIALS}. Approaches are also described for extending the software to use \emph{XDS} or other programs.
|
|
| 12. |
- Bengtsson, Viktor E. G., 1989-, et al.
(författare)
-
Scipion-ED : a graphical user interface for batch processing and analysis of 3D ED/MicroED data
- 2022
-
Ingår i: Journal of applied crystallography. - : International Union of Crystallography (IUCr). - 0021-8898 .- 1600-5767. ; 55:3, s. 638-646
-
Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional electron diffraction (3D ED)/microcrystal electron diffraction (MicroED) techniques are gaining in popularity. However, the data processing often does not fit existing graphical user interface software, instead requiring the use of the terminal or scripting. Scipion-ED, described in this article, provides a graphical user interface and extendable framework for processing of 3D ED/MicroED data. An illustrative project is described, in which multiple 3D ED/MicroED data sets collected on tetragonal lysozyme were processed with DIALS through the Scipion-ED interface. The ability to resolve unmodelled features in the electrostatic potential map was compared between three strategies for merging data sets.
|
|
| 13. |
- Bortolini, C., et al.
(författare)
-
Atomic Structure of Amyloid Crystals
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A deep understanding of the self-assembly and crystallization of biomolecules as highly ordered biomaterials is crucial to enable the design and the generation of complex functional systems for cutting-edge applications in nanotechnology and biomedicine. In this work, we determined the atomic structure of Aβ16-20 crystals, a fragment of amyloid-β which aberrant folding is linked to the etiology of Alzheimer’s disease, the most common cause of dementia. We detailed the hierarchical aggregation mechanism of Aβ16-20 into highly ordered crystals and revealed that the self-assembly is reversible, leading to the formation of oligomers as an intermediate. Our structural investigation combined with molecular dynamics simulations highlights how a combination of favorable non-covalent interactions drives the efficient fast self-assembly and enhanced stability. We studied the chemical and surface properties of amyloid crystals, including their mechanical properties and their capability to transmit light; the long-rang order of Aβ16-20 crystals enables them to be used as optical waveguide materials for biologically based modulation and sensing. Our results shed new light on pathogenic amyloid assembly at the atomic level and reveal the potential of amyloid crystals for applications in nanotechnology.
|
|
| 14. |
- Botella Mascarell, Carmen, 1979, et al.
(författare)
-
On the performance of joint processing schemes over the cluster area
- 2010
-
Ingår i: IEEE Vehicular Technology Conference Spring, Taipei, Taiwan, May 2010. - 1550-2252. - 9781424425181 ; 2010-January, s. 1-5
-
Konferensbidrag (refereegranskat)abstract
- In this paper, three joint processing schemes for the downlink are characterized and compared within a cluster of base stations. The motivation of this study is to analyze the performance of these schemes over the cluster area, as a first step towards designing an adaptive joint processing scheme supporting dynamic usage scenarios. Each one of the analyzed schemes, the centralized, partial and distributed joint processing approaches, requires a different amount of available channel knowledge at the transmitter side, inter-base information exchange and feedback from the users. In addition, these schemes show varying capabilities to serve the users depending on their location in the cluster area. Therefore, in a real scenario, an adaptive joint processing scheme encompassing the three schemes could be used by the cluster of base stations. Simulation results show that, assuming coherent transmission, the centralized joint processing scheme outperforms with 25% the partial joint processing scheme and with 50% the distributed joint processing approach in the cell edge when a backhaul-load weighted average sum-rate per cell metric is taken into account.
|
|
| 15. |
- Broadhurst, Edward T., et al.
(författare)
-
Polymorph evolution during crystal growth studied by 3D electron diffraction
- 2020
-
Ingår i: IUCrJ. - 2052-2525. ; 7, s. 5-9
-
Tidskriftsartikel (refereegranskat)abstract
- 3D electron diffraction (3DED) has been used to follow polymorph evolution in the crystallization of glycine from aqueous solution. The three polymorphs of glycine which exist under ambient conditions follow the stability order beta < alpha < gamma. The least stable beta polymorph forms within the first 3 min, but this begins to yield the alpha-form after only 1 min more. Both structures could be determined from continuous rotation electron diffraction data collected in less than 20 s on crystals of thickness similar to 100 nm. Even though the gamma-form is thermodynamically the most stable polymorph, kinetics favour the alpha-form, which dominates after prolonged standing. In the same sample, some beta and one crystallite of the gamma polymorph were also observed.
|
|
| 16. |
- Carmona, Francisco J., et al.
(författare)
-
Coordination Modulation Method To Prepare New Metal-Organic Framework-Based CO-Releasing Materials
- 2018
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 10:37, s. 31158-31167
-
Tidskriftsartikel (refereegranskat)abstract
- Aluminum-based metal organic frameworks (MOFs), [Al(OH)(SDC)](n), (H2SDC: 4,4'-stilbenedicarboxylic acid), also known as CYCU-3, were prepared by means of the coordination modulation method to produce materials with different crystal size and morphology. In particular, we screened several reagent concentrations (20-60 mM) and modulator/ligand ratios (0-50), leading to 20 CYCU x_y materials (x: reagent concentration, y = modulator/ligand ratio) with different particle size and morphology. Noteworthy, the use of high modulator/ligand ratio gives rise to a new phase of CYCU-3 (CYCU-3' x_50 series), which was structurally analyzed. Afterward, to test the potential of these materials as CO-prodrug carriers, we selected three of them to adsorb the photo- and bioactive CO-releasing molecule (CORM) ALF794 [Mo(CNCMe2CO2H)(3)(CO)(3)] (CNCMe2CO2H = 2-isocyano-2-methyl propionic acid): (i) CYCU-3 20_0, particles in the nanometric range; (ii) CYCU-3 50_5, bar-type particles with heterogeneous size, and (iii) CYCU-3' 50_50, a new phase analogous to pristine CYCU-3. The corresponding hybrid materials were fully characterized, revealing that CYCU-3 20_0 with the smallest particle size was not stable under the drug loading conditions. Regarding the other two materials, similar ALF794 loadings were found (0.20 and 0.19 CORM/MOF molar ratios for ALF794@CYCU-3 50_5 and ALF794@CYCU-3' 50_50, respectively). In addition, these hybrid systems behave as CO-releasing materials (CORMAs), retaining the photoactive properties of the pristine CORM in both phosphate saline solution and solid state. Finally, the metal leaching studies in solution confirmed that ALF794@CYCU-3' 50_50 shows a good retention capacity toward the potentially toxic molybdenum fragments (7S% of retention after 72 h), which is the lowest value reported for a MOF-based CORMA to date.
|
|
| 17. |
- Chen, Xin, 1980, et al.
(författare)
-
Improved resource allocation strategy in SU-CoMP network
- 2011
-
Ingår i: The Journal of China Universities of Posts and Telecommunications. - 2210-5123. ; 18:4, s. 7-12
-
Tidskriftsartikel (refereegranskat)abstract
- Coordinated Multi-Point transmission and reception (CoMP) for single user, named as SU-CoMP, is considered as an efficient approach tomitigate inter-cell interference in Orthogonal Frequency Division Multiple Access (OFDMA) systems. Two prevalent approaches in SU-CoMP areCoordinated Scheduling (CS) and Joint Processing (JP). Although JP in SU-CoMP has been proved to achieve a great link performanceimprovement for the cell-edge user, efficient Resource Allocation (RA) on the system level is quite needed. However, so far limited work has beendone considering JP, and most existing schemes achieved the improvement of cell-edge performance at cost of the cell-average performancedegradation compared to the single cell RA. In this paper, a two-phase strategy is proposed for SU-CoMP networks. CS and JP are combined toimprove both cell-edge and cell-average performance. Compared to the single cell RA, simulation results demonstrate that, the proposed strategyleads to both higher cell-average and cell-edge throughput.
|
|
| 18. |
- Chen, Xin, 1980, et al.
(författare)
-
Optimal and Efficient Power Allocation for OFDM Non-Coherent Cooperative Transmission
- 2012
-
Ingår i: IEEE Wireless Communications and Networking Conference, WCNC. - 1525-3511. - 9781467304375 ; , s. 1584-1589
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we study the subchannel (SC) power allocation for orthogonal frequency division multiplexing (OFDM) multiple access points (APs) systems with non-coherent cooperative transmission. The objective is to maximize the total capacity under per-AP power constraints. It can be proved that the optimal solution can be obtained by the combination of an optimal SC partition search and the power allocation across SCs for each feasible partition. Existing work exhaustively searched the optimal SC partition and used Lagrange dual method to compute the power allocation across SCs. Since the entire complexity increases exponentially with the number of SCs, the existing method is unsuitable for practical implementation. In this paper, we propose a novel optimal power allocation algorithm for non-coherent cooperative transmission with a much lower complexity. Firstly, a concept of “cut-off SC” is proposed for searching the optimal SC partition. Then, an efficient optimal power allocation algorithm across SCs is proposed for any given cut-off SC. Simulation results demonstrate that the proposed algorithm is optimal with a polynomial complexity, and ends within an acceptable number of iterations.
|
|
| 19. |
- Cho, Jung, et al.
(författare)
-
EMM-25 : The Structure of Two-Dimensional 11 x 10 Medium-Pore Borosilicate Zeolite Unraveled Using 3D Electron Diffraction
- 2021
-
Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 33:11, s. 4146-4153
-
Tidskriftsartikel (refereegranskat)abstract
- The structure of the novel medium-pore borosilicate zeolite EMM-25 has been determined by continuous rotation electron diffraction (cRED). EMM-25 crystallizes in the space group Cmcm with unit cell parameters a = 11.055, b = 22.912, and c = 24.914 angstrom and a composition of IC4H8(C11H25N)(2)I (2)[Si112.5B3.5O232]. The EMM-25 framework possesses a two-dimensional channel system composed of 10-ring channels connected via 11-ring windows. Its channel system is analogous to that of the medium-pore zeolite NU-87 framework but with 11- rather than 12-ring windows, suggesting a different shape selectivity. EMM-25 was first obtained using 1,4-bis(N-methyl-N,N-dihexylammonium)butane as an organic structure directing agent (OSDA). Based on a molecular docking study of the OSDA within the pores of the determined framework structure, a new ammonium dication OSDA with an improved fit was devised. By using this new OSDA, the synthesis time was reduced 80%, from 52 to just 10 days. Furthermore, cRED data revealed a structural disorder of the EMM-25 framework present as swinging zigzag chains. The introduction of the disorder, which is a consequence of geometry relaxation, was crucial for an accurate structure refinement. Lastly, the cRED data from as-made EMM-25 showed residual potential consistent with the location of the OSDA position determined from the Rietveld refinement, concluding a complete refinement of the as-made structure based on the cRED data.
|
|
| 20. |
- Christensen, Kirsten E, et al.
(författare)
-
A germanate built from 68126 cavity co-templated by a (H2O)16 water cluster and 2-methylpiperazine
- 2008
-
Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 47:41, s. 7868-7871
-
Tidskriftsartikel (refereegranskat)abstract
- Totally tubular: A new tubular germanate is cotemplated by 2-methylpiperazine and an (H2O)16 cluster in a hydro(solvo)thermal synthesis. The germanate features a large, highly symmetric 68126 cavity (see picture; yellow sphere) built from 12 Ge7X19 (X=O, OH, F) clusters (GeX6 red, GeX5 yellow, GeX4 green).
|
|
| 21. |
- Cichocka, Magdalena Ola, et al.
(författare)
-
A Porphyrinic Zirconium Metal-Organic Framework for Oxygen Reduction Reaction : Tailoring the Spacing between Active-Sites through Chain-Based Inorganic Building Units
- 2020
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 142:36, s. 15386-15395
-
Tidskriftsartikel (refereegranskat)abstract
- The oxygen reduction reaction (ORR) is central in carbon-neutral energy devices. While platinum group materials have shown high activities for ORR, their practical uses are hampered by concerns over deactivation, slow kinetics, exorbitant cost, and scarce nature reserve. The low cost yet high tunability of metal-organic frameworks (MOFs) provide a unique platform for tailoring their characteristic properties as new electrocatalysts. Herein, we report a new concept of design and present stable Zr-chain-based MOFs as efficient electrocatalysts for ORR. The strategy is based on using Zr-chains to promote high chemical and redox stability and, more importantly, tailor the immobilization and packing of redox active-sites at a density that is ideal to improve the reaction kinetics. The obtained new electrocatalyst, PCN-226, thereby shows high ORR activity. We further demonstrate PCN-226 as a promising electrode material for practical applications in rechargeable Zn-air batteries, with a high peak power density of 133 mW cm(-2). Being one of the very few electrocatalytic MOFs for ORR, this work provides a new concept by designing chain-based structures to enrich the diversity of efficient electrocatalysts and MOFs.
|
|
| 22. |
- Clabbers, Max T. B., et al.
(författare)
-
Visualizing drug binding interactions using microcrystal electron diffraction
- 2020
-
Ingår i: Communications biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- Visualizing ligand binding interactions is important for structure-based drug design and fragment-based screening methods. Rapid and uniform soaking with potentially reduced lattice defects make small macromolecular crystals attractive targets for studying drug binding using microcrystal electron diffraction (MicroED). However, so far no drug binding interactions could unambiguously be resolved by electron diffraction alone. Here, we use MicroED to study the binding of a sulfonamide inhibitor to human carbonic anhydrase isoform II (HCA II). We show that MicroED data can efficiently be collected on a conventional transmission electron microscope from thin hydrated microcrystals soaked with the clinical drug acetazolamide (AZM). The data are of high enough quality to unequivocally fit and resolve the bound inhibitor. We anticipate MicroED can play an important role in facilitating in-house fragment screening for drug discovery, complementing existing methods in structural biology such as X-ray and neutron diffraction. Clabbers et al. utilize MicroED to present the structure of both apo and inhibitor-bound human carbonic anhydrase II at a high resolution to clearly identify the interaction of the inhibitor, acetazolamide. This method eases the difficulty of both crystallizing the protein and soaking the inhibitor in a smaller protein crystal.
|
|
| 23. |
- Fang, Sisai, et al.
(författare)
-
Rate-based cell range expansion for mmWave massive MIMO enabled two-tier HetNets
- 2018
-
Ingår i: 2018 24th Asia-Pacific Conference on Communications, APCC 2018. ; , s. 275-279
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a Rate-based Cell Range Expansion (CRE) for mmWave massive Multiple Input Multiple Output (MIMO) enabled two-tier heterogeneous networks (Het-Nets) where macro base stations (BSs) operate at sub-6 GHz and small BSs operate at mmWave band. We design a new user association scheme with the consideration of disparities between macro BSs and small BSs, chiefly bandwidths combined with Signal to Interference plus Noise Ratio (SINR), although conventional CRE provides a fixed Cell Selection Offset (CSO) for all user equipments (UEs). A downlink model is put forth to analyze the performance of the proposed Rate-based CRE. Our scheme consists of two parts: CRE between small cells and CRE between macro cells and small cells. We also investigate the proposed method by evaluating the average user throughput and cell edge user throughput. System-level computer simulation results such as average user throughput and 5-percentile user throughput are provided. The results confirm that the proposed method can improve the average user throughput compared with the conventional CRE scheme and maintain the cell edge user throughput for such multi-frequency cooperative networks. Thus, this scheme is an effective solution for user association in 5G mmWave HetNets.
|
|
| 24. |
- Ge, Meng, 1993-, et al.
(författare)
-
Direct Location of Organic Molecules in Framework Materials by Three-Dimensional Electron Diffraction
- 2022
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 144:33, s. 15165-15174
-
Tidskriftsartikel (refereegranskat)abstract
- In the study of framework materials, probing interactions between frameworks and organic molecules is one of the most important tasks, which offers us a fundamental understanding of host–guest interactions in gas sorption, separation, catalysis, and framework structure formation. Single-crystal X-ray diffraction (SCXRD) is a conventional method to locate organic species and study such interactions. However, SCXRD demands large crystals whose quality is often vulnerable to, e.g., cracking on the crystals by introducing organic molecules, and this is a major challenge to use SCXRD for structural analysis. With the development of three-dimensional electron diffraction (3D ED), single-crystal structural analysis can be performed on very tiny crystals with sizes on the nanometer scale. Here, we analyze two framework materials, SU-8 and SU-68, with organic molecules inside their inorganic crystal structures. By applying 3D ED, with fast data collection and an ultralow electron dose (0.8–2.6 e– Å–2), we demonstrate for the first time that each nonhydrogen atom from the organic molecules can be ab initio located from structure solution, and they are shown as distinct and well-separated peaks in the difference electrostatic potential maps showing high accuracy and reliability. As a result, two different spatial configurations are identified for the same guest molecule in SU-8. We find that the organic molecules interact with the framework through strong hydrogen bonding, which is the key to immobilizing them at well-defined positions. In addition, we demonstrate that host–guest systems can be studied at room temperature. Providing high accuracy and reliability, we believe that 3D ED can be used as a powerful tool to study host–guest interactions, especially for nanocrystals.
|
|
| 25. |
- Ge, Xiaodong, et al.
(författare)
-
Amelioration of type 2 diabetes by the novel 6, 8-guanidyl luteolin quinone-chromium coordination via biochemical mechanisms and gut microbiota interaction
- 2023
-
Ingår i: JOURNAL OF ADVANCED RESEARCH. - : Elsevier. - 2090-1232 .- 2090-1224. ; 46, s. 173-188
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Luteolin is a plant-derived flavonoid that exhibits a broad range of pharmacological activ-ities. Studies on luteolin have mainly focused on its use for hyperlipidaemia prevention, whereas the capacity of the flavonoid to hinder hyperglycaemia development remains underexplored.Objectives: To probe the anti-hyperglycemic mechanism of 6,8-guanidyl luteolin quinone-chromium coordination (GLQ.Cr), and to assess its regulatory effect on intestinal microbiota in type 2 diabetes mel-litus (T2DM) mice.Methods: High-sucrose/high-fat diet-induced and intraperitoneal injection of streptozotocin was used to develop a T2DM model. Glycometabolism related indicators, histopathology, and gut microbiota compo-sition in caecum samples were evaluated, and RNA sequencing (RNA-seq) of liver samples was con-ducted. Faecal microbiota transplantation (FMT) was further used to verify the anti-hyperglycemic activity of intestinal microbiota.Results: The administration of GLQ.Cr alleviated hyperglycaemia symptoms by improving liver and pan-creatic functions and modulating gut microbe communities (Lactobacillus, Alistipes, Parabacteroides, Lachnoclostridium, and Desulfovibrio). RNA-seq analysis showed that GLQ.Cr mainly affected the peroxi-some proliferative activated receptor (PPAR) signalling pathway in order to regulate abnormal glucose metabolism. FMT significantly modulated the abundance of Lactobacillus, Alloprevotella, Alistipes, Bacteroides, Ruminiclostridium, Brevundimonas and Pseudomonas in the caecum to balance blood glucose levels and counteract T2DM mice inflammation.Conclusion: GLQ.Cr improved the abnormal glucose metabolism in T2DM mice by regulating the PPAR signalling pathway and modulating intestinal microbial composition. FMT can improve the intestinal microecology of the recipient and in turn ameliorate the symptoms of T2DM-induced hyperglycaemia.
|
|
