Philosophical transactions. Series A, Mathematical, physical, and engineering sciences最新文献_第6页

From pre- to post-big bang: an (almost) self-dual cosmological history. 从大爆炸前到大爆炸后:一个(几乎)自我对偶的宇宙学历史。

IF 5

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-08-22 Epub Date: 2022-07-04 DOI: 10.1098/rsta.2021.0179

M Gasperini

引用次数: 5

Editorial note. 编辑的注意。

IF 5

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-08-22 Epub Date: 2022-07-04 DOI: 10.1098/rsta.2022.0093

引用次数: 0

The cosmological constant problem and running vacuum in the expanding universe. 宇宙常数问题和膨胀宇宙中的运行真空。

IF 5

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-08-22 Epub Date: 2022-07-04 DOI: 10.1098/rsta.2021.0182

Joan Solà Peracaula

{"title":"The cosmological constant problem and running vacuum in the expanding universe.","authors":"Joan Solà Peracaula","doi":"10.1098/rsta.2021.0182","DOIUrl":"https://doi.org/10.1098/rsta.2021.0182","url":null,"abstract":"It is well known that quantum field theory (QFT) induces a huge value of the cosmological constant (CC), [Formula: see text], which is outrageously inconsistent with cosmological observations. We review here some aspects of this fundamental theoretical conundrum (the cosmological constant problem, CCP) and strongly argue in favour of the possibility that the cosmic vacuum density [Formula: see text] may be mildly evolving with the expansion rate [Formula: see text]. Such a 'running vacuum model' (RVM) proposal predicts an effective dynamical dark energy without postulating new ad hoc fields (quintessence and the like). Using the method of adiabatic renormalization within QFT in curved space-time, we find that [Formula: see text] acquires a dynamical component [Formula: see text] caused by the quantum matter effects. There are also [Formula: see text] ([Formula: see text]) contributions, some of which may trigger inflation in the early universe. Remarkably, the evolution of the adiabatically renormalized [Formula: see text] is not affected by dangerous terms proportional to the quartic power of the masses ([Formula: see text]) of the quantized matter fields. Traditionally, these terms have been the main source of trouble as they are responsible for the extreme fine-tuning feature of the CCP. In the context under study, however, the late time [Formula: see text] around [Formula: see text] is given by a dominant term ([Formula: see text]) plus the aforementioned mild dynamical component [Formula: see text] (with [Formula: see text]), which makes the RVM to mimic quintessence. Finally, on the phenomenological side, we show that the RVM may be instrumental in alleviating some of the most challenging problems (so-called 'tensions') afflicting nowadays the observational consistency of the 'concordance' [Formula: see text]CDM model, such as the [Formula: see text] and [Formula: see text] tensions. This article is part of the theme issue 'The future of mathematical cosmology, Volume 2'.","PeriodicalId":286094,"journal":{"name":"Philosophical transactions. Series A, Mathematical, physical, and engineering sciences","volume":" ","pages":"20210182"},"PeriodicalIF":5.0,"publicationDate":"2022-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40479004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 39

Full-hand electrotactile feedback using electronic skin and matrix electrodes for high-bandwidth human-machine interfacing. 使用电子皮肤和矩阵电极的全手电触觉反馈用于高带宽人机接口。

IF 5

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-07-25 Epub Date: 2022-06-06 DOI: 10.1098/rsta.2021.0017

Yahya Abbass, Strahinja Dosen, Lucia Seminara, Maurizio Valle

{"title":"Full-hand electrotactile feedback using electronic skin and matrix electrodes for high-bandwidth human-machine interfacing.","authors":"Yahya Abbass, Strahinja Dosen, Lucia Seminara, Maurizio Valle","doi":"10.1098/rsta.2021.0017","DOIUrl":"https://doi.org/10.1098/rsta.2021.0017","url":null,"abstract":"Tactile feedback is relevant in a broad range of human-machine interaction systems (e.g. teleoperation, virtual reality and prosthetics). The available tactile feedback interfaces comprise few sensing and stimulation units, which limits the amount of information conveyed to the user. The present study describes a novel technology that relies on distributed sensing and stimulation to convey comprehensive tactile feedback to the user of a robotic end effector. The system comprises six flexible sensing arrays (57 sensors) integrated on the fingers and palm of a robotic hand, embedded electronics (64 recording channels), a multichannel stimulator and seven flexible electrodes (64 stimulation pads) placed on the volar side of the subject's hand. The system was tested in seven subjects asked to recognize contact positions and identify contact sliding on the electronic skin, using distributed anode configuration (DAC) and single dedicated anode configuration. The experiments demonstrated that DAC resulted in substantially better performance. Using DAC, the system successfully translated the contact patterns into electrotactile profiles that the subjects could recognize with satisfactory accuracy ([Formula: see text] for static and [Formula: see text] for dynamic patterns). The proposed system is an important step towards the development of a high-density human-machine interfacing between the user and a robotic hand. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.","PeriodicalId":286094,"journal":{"name":"Philosophical transactions. Series A, Mathematical, physical, and engineering sciences","volume":" ","pages":"20210017"},"PeriodicalIF":5.0,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40407036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Cleanroom strategies for micro- and nano-fabricating flexible implantable neural electronics 微纳米制造柔性植入式神经电子学的洁净室策略

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-06-06 DOI: 10.1098/rsta.2021.0009

Finlay Walton, Maria Cerezo-Sanchez, Eve McGlynn, Rupam Das, H. Heidari

{"title":"Cleanroom strategies for micro- and nano-fabricating flexible implantable neural electronics","authors":"Finlay Walton, Maria Cerezo-Sanchez, Eve McGlynn, Rupam Das, H. Heidari","doi":"10.1098/rsta.2021.0009","DOIUrl":"https://doi.org/10.1098/rsta.2021.0009","url":null,"abstract":"Implantable electronic neural interfaces typically take the form of probes and are made with rigid materials such as silicon and metals. These have advantages such as compatibility with integrated microchips, simple implantation and high-density nanofabrication but tend to be lacking in terms of biointegration, biocompatibility and durability due to their mechanical rigidity. This leads to damage to the device or, more importantly, the brain tissue surrounding the implant. Flexible polymer-based probes offer superior biocompatibility in terms of surface biochemistry and better matched mechanical properties. Research which aims to bring the fabrication of electronics on flexible polymer substrates to the nano-regime is remarkably sparse, despite the push for flexible consumer electronics in the last decade or so. Cleanroom-based nanofabrication techniques such as photolithography have been used as pattern transfer methods by the semiconductor industry to produce single nanometre scale devices and are now also used for making flexible circuit boards. There is still much scope for miniaturizing flexible electronics further using photolithography, bringing the possibility of nanoscale, non-invasive, high-density flexible neural interfacing. This work explores the fabrication challenges of using photolithography and complementary techniques in a cleanroom for producing flexible electronic neural probes with nanometre-scale features. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.","PeriodicalId":286094,"journal":{"name":"Philosophical transactions. Series A, Mathematical, physical, and engineering sciences","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115002035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

A CMOS–memristor hybrid system for implementing stochastic binary spike timing-dependent plasticity 一种cmos -忆阻器混合系统，用于实现随机二进制尖峰时间相关的可塑性

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-06-06 DOI: 10.1098/rsta.2021.0018

J. Ahmadi-Farsani, Saverio Ricci, S. Hashemkhani, D. Ielmini, B. Linares-Barranco, T. Serrano-Gotarredona

{"title":"A CMOS–memristor hybrid system for implementing stochastic binary spike timing-dependent plasticity","authors":"J. Ahmadi-Farsani, Saverio Ricci, S. Hashemkhani, D. Ielmini, B. Linares-Barranco, T. Serrano-Gotarredona","doi":"10.1098/rsta.2021.0018","DOIUrl":"https://doi.org/10.1098/rsta.2021.0018","url":null,"abstract":"This paper describes a fully experimental hybrid system in which a 4×4 memristive crossbar spiking neural network (SNN) was assembled using custom high-resistance state memristors with analogue CMOS neurons fabricated in 180 nm CMOS technology. The custom memristors used NMOS selector transistors, made available on a second 180 nm CMOS chip. One drawback is that memristors operate with currents in the micro-amperes range, while analogue CMOS neurons may need to operate with currents in the pico-amperes range. One possible solution was to use a compact circuit to scale the memristor-domain currents down to the analogue CMOS neuron domain currents by at least 5–6 orders of magnitude. Here, we proposed using an on-chip compact current splitter circuit based on MOS ladders to aggressively attenuate the currents by over 5 orders of magnitude. This circuit was added before each neuron. This paper describes the proper experimental operation of an SNN circuit using a 4×4 1T1R synaptic crossbar together with four post-synaptic CMOS circuits, each with a 5-decade current attenuator and an integrate-and-fire neuron. It also demonstrates one-shot winner-takes-all training and stochastic binary spike-timing-dependent-plasticity learning using this small system. This article is part of the theme issue ‘Advanced neurotechnologies: translating innovation for health and well-being’.","PeriodicalId":286094,"journal":{"name":"Philosophical transactions. Series A, Mathematical, physical, and engineering sciences","volume":"198 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115970501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Spatio-temporal feature extraction in sensory electroneurographic signals 感官神经电信号的时空特征提取

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-06-06 DOI: 10.1098/rsta.2021.0268

C. Silveira, R. Khushaba, E. Brunton, K. Nazarpour

{"title":"Spatio-temporal feature extraction in sensory electroneurographic signals","authors":"C. Silveira, R. Khushaba, E. Brunton, K. Nazarpour","doi":"10.1098/rsta.2021.0268","DOIUrl":"https://doi.org/10.1098/rsta.2021.0268","url":null,"abstract":"The recording and analysis of peripheral neural signal can provide insight for various prosthetic and bioelectronics medicine applications. However, there are few studies that investigate how informative features can be extracted from population activity electroneurographic (ENG) signals. In this study, five feature extraction frameworks were implemented on sensory ENG datasets and their classification performance was compared. The datasets were collected in acute rat experiments where multi-channel nerve cuffs recorded from the sciatic nerve in response to proprioceptive stimulation of the hindlimb. A novel feature extraction framework, which incorporates spatio-temporal focus and dynamic time warping, achieved classification accuracies above 90% while keeping a low computational cost. This framework outperformed the remaining frameworks tested in this study and has improved the discrimination accuracy of the sensory signals. Thus, this study has extended the tools available to extract features from sensory population activity ENG signals. This article is part of the theme issue ‘Advanced neurotechnologies: translating innovation for health and well-being’.","PeriodicalId":286094,"journal":{"name":"Philosophical transactions. Series A, Mathematical, physical, and engineering sciences","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126523521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

An affordable implantable vagus nerve stimulator system for use in animal research 一种可负担得起的用于动物研究的植入式迷走神经刺激系统

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-06-06 DOI: 10.1098/rsta.2021.0010

Ángel Canal-Alonso, Roberto Casado-Vara, Orlando Castellano, Jorge Herrera-Santos, Jaime Gonçalves, Sergio Márquez-Sánchez, Jesús M. Gonçalves, J. Corchado

引用次数: 2

Preface to ‘Advanced neurotechnologies: translating innovation for health and well-being’ 前言“先进神经技术:为健康和福祉转化创新”

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-06-06 DOI: 10.1098/rsta.2021.0004

Rupam Das, G. Curia, H. Heidari

{"title":"Preface to ‘Advanced neurotechnologies: translating innovation for health and well-being’","authors":"Rupam Das, G. Curia, H. Heidari","doi":"10.1098/rsta.2021.0004","DOIUrl":"https://doi.org/10.1098/rsta.2021.0004","url":null,"abstract":"In the nervous system, huge amounts of neurons constantly induce and transmit electrophysiological signals to communicate between neurons and brain regions. Innovative neurotechnologies have added significantly to neural engineering and have led directly to many fundamental scientific insights into the function of the central and peripheral nervous systems. This issue addressed the novel approaches toward biocompatible neural interfaces, thin and flexible electronics and wireless circuits and systems, which will allow readers to identify the requirements, challenges and future directions related to biointegrated implantable neurotechnologies. Additionally, this special issue aims to report the latest advances and future trends of critical techniques and frameworks in implantable neural devices, which will allow biomedical researchers to identify new opportunities. The theme issue starts with a research article by Lee & Fried [1], which aims to show that innovative magnetic stimulation of the visual cortex (V1) using microcoils induces spatially confined activation in the secondary visual cortex (V2) in mouse brain slices. They demonstrated that, compared with the traditional electrical stimulation, the microcoils-based magnetic stimulation is better for confining the activation to a small region in V1 and produces more precise and sustained","PeriodicalId":286094,"journal":{"name":"Philosophical transactions. Series A, Mathematical, physical, and engineering sciences","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116032360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Neural microprobe modelling and microfabrication for improved implantation and mechanical failure mitigation 神经微探针建模和微制造改进植入和机械故障缓解

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Pub Date : 2022-06-06 DOI: 10.1098/rsta.2021.0007

Eve McGlynn, Finlay Walton, Rupam Das, H. Heidari

{"title":"Neural microprobe modelling and microfabrication for improved implantation and mechanical failure mitigation","authors":"Eve McGlynn, Finlay Walton, Rupam Das, H. Heidari","doi":"10.1098/rsta.2021.0007","DOIUrl":"https://doi.org/10.1098/rsta.2021.0007","url":null,"abstract":"Careful design and material selection are the most beneficial strategies to ensure successful implantation and mitigate the failure of a neural probe in the long term. In order to realize a fully flexible implantable system, the probe should be easily manipulated by neuroscientists, with the potential to bend up to 90°. This paper investigates the impact of material choice, probe geometry, and crucially, implantation angle on implantation success through finite-element method simulations in COMSOL Multiphysics followed by cleanroom microfabrication. The designs introduced in this paper were fabricated using two polyimides: (i) PI-2545 as a release layer and (ii) photodefinable HD-4110 as the probe substrate. Four different designs were microfabricated, and the implantation tests were compared between an agarose brain phantom and lamb brain samples. The probes were scanned in a 7 T PharmaScan MRI coil to investigate potential artefacts. From the simulation, a triangular base and 50 µm polymer thickness were identified as the optimum design, which produced a probe 57.7 µm thick when fabricated. The probes exhibit excellent flexibility, exemplified in three-point bending tests performed with a DAGE 4000Plus. Successful implantation is possible for a range of angles between 30° and 90°. This article is part of the theme issue ‘Advanced neurotechnologies: translating innovation for health and well-being’.","PeriodicalId":286094,"journal":{"name":"Philosophical transactions. Series A, Mathematical, physical, and engineering sciences","volume":"215 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133903392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6