| 1. |
- Lin, Jiuluan, et al.
(författare)
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Novel Method to Identify the Precentral Gyrus and Its Detailed Functional Distribution in Real Brain Surfaces Using Reconstructed 3D Brain Surface Imaging
- 2015
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Ingår i: JOURNAL OF MEDICAL IMAGING AND HEALTH INFORMATICS. - : American Scientific Publishers. - 2156-7018 .- 2156-7026. ; 5:2, s. 216-222
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To study the use of reconstructed 3D brain surface imaging (RBSI) to identify the precentral gyrus and its detailed functional distribution in epileptic patients. Method: A total of 12 refractory epilepsy cases that need intracranial electrode implantation were studied. In these patients, pre-operative magnetic resonance imaging (MRI) and functional MRI (fMRI) were conducted, and a cranial computed tomography (CT) scan was performed after electrode implantation. The RBSI was accomplished using Brain Voyager software based on MRI data, and then the 3D brain surface was integrated with the subdural electrode CT scan. The precentral gyrus was found in the reconstructed brain surface imaging according to their anatomical shape, and then were identified in the surgical field by comparing the exposed gyrus in the RBSI with the help of intraoperative photographs. Results: Total 12 cases of precentral gyrus was found and marked in the RBSI. There were 101 electrodes covering the precentral gyrus and 73 (72%) of them had motor response to electrical stimulation. In the contrast, (the area which is 1 cm ahead of the precentral gyrus), the motor response rate was 13% (17/130) (p < 0.05). During fMRI, 100% of the precentral gyrus and 58% (7/12) of post central gyrus was activated during hand movement. Whereas, no activation of the areas ahead of precentral gyrus was seen showing a significant difference between precentral gyrus and gyrus ahead. Conclusion: Our results demonstrated that using RBSI technique, it is possible to identify the precentral gyrus with precision.
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| 2. |
- Liu, Shiping, et al.
(författare)
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Population Genomics Reveal Recent Speciation and Rapid Evolutionary Adaptation in Polar Bears
- 2014
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 157:4, s. 785-794
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Tidskriftsartikel (refereegranskat)abstract
- Polar bears are uniquely adapted to life in the High Arctic and have undergone drastic physiological changes in response to Arctic climates and a hyper-lipid diet of primarily marine mammal prey. We analyzed 89 complete genomes of polar bear and brown bear using population genomic modeling and show that the species diverged only 479-343 thousand years BP. We find that genes on the polar bear lineage have been under stronger positive selection than in brown bears; nine of the top 16 genes under strong positive selection are associated with cardiomyopathy and vascular disease, implying important reorganization of the cardiovascular system. One of the genes showing the strongest evidence of selection, APOB, encodes the primary lipoprotein component of low-density lipoprotein (LDL); functional mutations in APOB may explain how polar bears are able to cope with life-long elevated LDL levels that are associated with high risk of heart disease in humans.
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| 3. |
- Yu, Yewei, et al.
(författare)
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Neural network based iterative learning control for magnetic shape memory alloy actuator with iteration-dependent uncertainties
- 2023
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Ingår i: Mechanical Systems and Signal Processing. - : Elsevier BV. - 0888-3270 .- 1096-1216. ; 187
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic shape memory alloy based actuator (MSMA-BA) is an indispensable component mechanism for high-precision positioning systems as it possesses the advantages of high precision, low energy consumption, and large stroke. However, hysteresis is an intrinsic property of MSMA material, which seriously affects the positioning accuracy of MSMA-BA. In this study, we propose a multi meta-model approach incorporating the nonlinear auto-regressive moving average with exogenous inputs (NARMAX) and Bouc–Wen (BW) models to describe the complex dynamic hysteresis of MSMA-BA. In particular, the BW model is introduced into the NARMAX model as an exogenous variable function, and a wavelet neural network (WNN) is adopted to construct the nonlinear function of the multi meta-model. In addition, iterative learning control is combined with a WNN to improve its convergence speed. A two-valued function is employed in the controller design process, so as to make use of history iteration information in updating control input. The main contribution of this study is the convergence analysis of the proposed iteration learning controller with iteration-dependent uncertainties (non-strict repetition of the initial state and varying iteration length). The experiments conducted on the MSMA-BA illustrate the validity of the proposed control scheme.
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| 4. |
- Zhang, Juqing, et al.
(författare)
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Super-enhancers conserved within placental mammals maintain stem cell pluripotency
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 119:40
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Tidskriftsartikel (refereegranskat)abstract
- Despite pluripotent stem cells sharing key transcription factors, their maintenance involves distinct genetic inputs. Emerging evidence suggests that super-enhancers (SEs) can function as master regulatory hubs to control cell identity and pluripotency in humans and mice. However, whether pluripotency-associated SEs share an evolutionary origin in mammals remains elusive. Here, we performed comprehensive comparative epigenomic and transcription factor binding analyses among pigs, humans, and mice to identify pluripotency-associated SEs. Like typical enhancers, SEs displayed rapid evolu-tion in mammals. We showed that BRD4 is an essential and conserved activator for mammalian pluripotency-associated SEs. Comparative motif enrichment analysis revealed 30 shared transcription factor binding motifs among the three species. The majority of transcriptional factors that bind to identified motifs are known regulators associated with pluripotency. Further, we discovered three pluripotency-associated SEs (SE-SOX2, SE-PIM1, and SE-FGFR1) that displayed remarkable conservation in pla-cental mammals and were sufficient to drive reporter gene expression in a pluripotency-dependent manner. Disruption of these conserved SEs through the CRISPR-Cas9 approach severely impaired stem cell pluripotency. Our study provides insights into the understanding of conserved regulatory mechanisms underlying the maintenance of plu-ripotency as well as species-specific modulation of the pluripotency-associated regula-tory networks in mammals.
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| 5. |
- Zhao, Xue, et al.
(författare)
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BCN-Encapsulated Nano-nickel Synergistically Promotes Ambient Electrochemical Dinitrogen Reduction
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 12:28, s. 31419-31430
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Tidskriftsartikel (refereegranskat)abstract
- The electricity provided by solar or wind power can drive nitrogen in the atmosphere, combining with ubiquitous water to form ammonia, and distributed production methods can alleviate the irreversible damage to the environment caused by the energy-intensive Haber-Bosch process. Here, we have designed a novel Ni-doped BCN heterojunction (S/M-BOPS-1) as a catalyst for the electrochemical nitrogen reduction reaction (NRR). The ammonia yield rate and Faraday efficiency in NRR driven by S/M-BOPS-1 reach up to 16.72 mu g(-1) h(-1) cm(-2) and 13.06%, respectively. Moreover, S/M-BOPS-1 still maintains high NRR activity and excellent stability after recycling for eight times and long-time operation of 12 h. Using density functional theory calculations, we reveal a possible NRR path for N-2 to NH3 on Ni, BCN, and the S/M-BOPS-1 composite surfaces. The interaction between the BCN matrix and Ni nanoparticles promotes a synergetic effect for the electrochemical NRR efficiency due to the partial electron transfer from the Ni particles to BCN that inhibits hydrogen evolution reaction and decreases the rate-determining step on Ni surfaces toward NRR by similar to 1.5 times. Therefore, efficient NRR performance can be achieved by tuning the electronic properties of non-noble metals via the formation of a heterointerface.
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| 6. |
- Zhao, Xue, et al.
(författare)
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Potassium ions promote electrochemical nitrogen reduction on nano-Au catalysts triggered by bifunctional boron supramolecular assembly
- 2020
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 8:26, s. 13086-13094
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical way of reducing nitrogen to ammonia presents green and economic advantages to dial down irreversible damage caused by the energy-intensive Haber-Bosch process. Here, we introduce an advanced catalyst CB[7]-K-2[B12H12]@Au with highly dispersed and ultrafine nano-gold. The CB[7]-K-2[B12H12]@Au electrochemically driven ammonia yield and Faraday efficiency is as high as 41.69 mu g h(-1)mg(cat.)(-1)and 29.53% (at -0.4 Vvs.RHE), respectively, reaching the US Department of Energy (DOE) utility index of ambient ammonia production along with excellent cycle stability and tolerance that indicates a high potential of industrial practical value. Experimental results and theoretical calculations show that the key to an excellent electrochemical nitrogen reduction performance lies in the smart design of the CB[7]-K-2[B12H12]@Au catalyst combining the stable substrate anchored Au nanoparticles and K(+)ions that effectively prevent the hydrogen evolution reaction and polarize *N(2)leading to lowering of the rate determining step. This research will promote the further development of electrochemical ammonia production with low environmental impact.
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