During the summer monsoon (June–September) season, drought poses challenges for agricultural activities and water availability in India. We develop a framework considering the timing, areal coverage and severity that can be used for the assessment of meteorological droughts as the monsoon season progresses. We estimate the benchmark worst droughts within the monsoon season (June, July, August and September) using the long-term (1901–2020) gridded rainfall. The benchmark worst droughts were identified considering the extent and severity of drought using the Drought Severity Coverage Index (DSCI). The worst meteorological drought in June, July, August and September occurred in 1923, 2002, 1937 and 1907 with a return period of 68, 200, 147, 188 years, respectively. The worst drought in the entire summer monsoon season occurred in 1918, which had a return period of 238 years. The benchmark droughts during June 1923, July 2002 and monsoon 1918 were associated with the warm sea surface temperature over the equatorial Pacific Ocean. The other two droughts (1937 and 1907) were linked with the off-equatorial warming over the Indo-Pacific region. The leading mode of variability in the Standardized Precipitation Index obtained from empirical orthogonal function analysis showed that the western and central parts of the country are most affected by droughts during the summer monsoon season. The second leading mode exhibited declining trends in rainfall with a bipolar spatial variability centred over the Gangetic Plain and southern India. The estimated DSCI for a 2–500 return period can be used for the drought assessment during the monsoon season in India. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.
{"title":"Benchmark worst droughts during the summer monsoon in India","authors":"V. Mishra, M. Mujumdar, S. Mahto","doi":"10.1098/rsta.2021.0291","DOIUrl":"https://doi.org/10.1098/rsta.2021.0291","url":null,"abstract":"During the summer monsoon (June–September) season, drought poses challenges for agricultural activities and water availability in India. We develop a framework considering the timing, areal coverage and severity that can be used for the assessment of meteorological droughts as the monsoon season progresses. We estimate the benchmark worst droughts within the monsoon season (June, July, August and September) using the long-term (1901–2020) gridded rainfall. The benchmark worst droughts were identified considering the extent and severity of drought using the Drought Severity Coverage Index (DSCI). The worst meteorological drought in June, July, August and September occurred in 1923, 2002, 1937 and 1907 with a return period of 68, 200, 147, 188 years, respectively. The worst drought in the entire summer monsoon season occurred in 1918, which had a return period of 238 years. The benchmark droughts during June 1923, July 2002 and monsoon 1918 were associated with the warm sea surface temperature over the equatorial Pacific Ocean. The other two droughts (1937 and 1907) were linked with the off-equatorial warming over the Indo-Pacific region. The leading mode of variability in the Standardized Precipitation Index obtained from empirical orthogonal function analysis showed that the western and central parts of the country are most affected by droughts during the summer monsoon season. The second leading mode exhibited declining trends in rainfall with a bipolar spatial variability centred over the Gangetic Plain and southern India. The estimated DSCI for a 2–500 return period can be used for the drought assessment during the monsoon season in India. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84935774","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}
O. Mazdiyasni, S. Jiwa, M. M. Kinnon, A. Carlos-Carlos, S. Samuelsen, JE Schubert, A. AghaKouchak, MG Burgess, EM Costigliolo, C. Frieder, BT Saenz, MC Long, J. DeAngelo, K. Alexander, C. Hong, M. Shaner, K. Caldeira, I. McKay, J. Lloyd, EB Olson, L. Liebermann, J. McBride
Despite major improvements in weather and climate modelling and substantial increases in remotely sensed observations, drought prediction remains a major challenge. After a review of the existing methods, we discuss major research gaps and opportunities to improve drought prediction. We argue that current approaches are top-down, assuming that the process(es) and/or driver(s) are known—i.e. starting with a model and then imposing it on the observed events (reality). With the help of an experiment, we show that there are opportunities to develop bottom-up drought prediction models—i.e. starting from the reality (here, observed events) and searching for model(s) and driver(s) that work. Recent advances in artificial intelligence and machine learning provide significant opportunities for developing bottom-up drought forecasting models. Regardless of the type of drought forecasting model (e.g. machine learning, dynamical simulations, analogue based), we need to shift our attention to robustness of theories and outputs rather than event-based verification. A shift in our focus towards quantifying the stability of uncertainty in drought prediction models, rather than the goodness of fit or reproducing the past, could be the first step towards this goal. Finally, we highlight the advantages of hybrid dynamical and statistical models for improving current drought prediction models. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.
{"title":"Status and prospects for drought forecasting: opportunities in artificial intelligence and hybrid physical–statistical forecasting","authors":"O. Mazdiyasni, S. Jiwa, M. M. Kinnon, A. Carlos-Carlos, S. Samuelsen, JE Schubert, A. AghaKouchak, MG Burgess, EM Costigliolo, C. Frieder, BT Saenz, MC Long, J. DeAngelo, K. Alexander, C. Hong, M. Shaner, K. Caldeira, I. McKay, J. Lloyd, EB Olson, L. Liebermann, J. McBride","doi":"10.1098/rsta.2021.0288","DOIUrl":"https://doi.org/10.1098/rsta.2021.0288","url":null,"abstract":"Despite major improvements in weather and climate modelling and substantial increases in remotely sensed observations, drought prediction remains a major challenge. After a review of the existing methods, we discuss major research gaps and opportunities to improve drought prediction. We argue that current approaches are top-down, assuming that the process(es) and/or driver(s) are known—i.e. starting with a model and then imposing it on the observed events (reality). With the help of an experiment, we show that there are opportunities to develop bottom-up drought prediction models—i.e. starting from the reality (here, observed events) and searching for model(s) and driver(s) that work. Recent advances in artificial intelligence and machine learning provide significant opportunities for developing bottom-up drought forecasting models. Regardless of the type of drought forecasting model (e.g. machine learning, dynamical simulations, analogue based), we need to shift our attention to robustness of theories and outputs rather than event-based verification. A shift in our focus towards quantifying the stability of uncertainty in drought prediction models, rather than the goodness of fit or reproducing the past, could be the first step towards this goal. Finally, we highlight the advantages of hybrid dynamical and statistical models for improving current drought prediction models. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90580498","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}
Anthropogenic climate change is expected to alter drought risk in the future. However, droughts are not uncommon or unprecedented, as documented in tree-ring-based reconstructions of the summer average Palmer drought severity index (PDSI). Using an unsupervised machine-learning method trained on these reconstructions of pre-industrial climate, we identify outliers: years in which the spatial pattern of PDSI is unusual relative to ‘normal' variability. We show that in many regions, outliers are more frequently identified in the twentieth and twenty-first centuries. This trend is more pronounced when the regional drought atlases are combined into a single global dataset. By definition, outlier patterns at the 10% level are expected to occur once per decade, but from 1950 to 2000 more than 6 years per decade are identified as outliers in the global drought atlas (GDA). Extending the GDA through 2020 using an observational dataset suggests that anomalous global drought conditions are present in 80% of years in the twenty-first century. Our results indicate, without recourse to climate models, that the world is more frequently experiencing drought conditions that are highly unusual in the context of past natural climate variability. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.
{"title":"Using machine learning to identify novel hydroclimate states","authors":"K. Marvel, B. Cook","doi":"10.1098/rsta.2021.0287","DOIUrl":"https://doi.org/10.1098/rsta.2021.0287","url":null,"abstract":"Anthropogenic climate change is expected to alter drought risk in the future. However, droughts are not uncommon or unprecedented, as documented in tree-ring-based reconstructions of the summer average Palmer drought severity index (PDSI). Using an unsupervised machine-learning method trained on these reconstructions of pre-industrial climate, we identify outliers: years in which the spatial pattern of PDSI is unusual relative to ‘normal' variability. We show that in many regions, outliers are more frequently identified in the twentieth and twenty-first centuries. This trend is more pronounced when the regional drought atlases are combined into a single global dataset. By definition, outlier patterns at the 10% level are expected to occur once per decade, but from 1950 to 2000 more than 6 years per decade are identified as outliers in the global drought atlas (GDA). Extending the GDA through 2020 using an observational dataset suggests that anomalous global drought conditions are present in 80% of years in the twenty-first century. Our results indicate, without recourse to climate models, that the world is more frequently experiencing drought conditions that are highly unusual in the context of past natural climate variability. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"564 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78044833","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}
D. Goodwin, I. Holman, C. Sutcliffe, G. Salmoral, Liwa Pardthaisong, S. Visessri, C. Ekkawatpanit, D. Rey
The intensification of drought affects agricultural production, leading to economic losses, environmental degradation and social impacts. To move toward more resilient system configurations requires understanding the processes that shape farmers' adaptation amidst complex institutional contexts. Social networks are an important part of collective action for supporting adaptive capacity and there are continuing calls to strengthen network connectivity for agricultural governance under the impacts of climate change. Through a survey of 176 farmers in northern Thailand, we explore the extent to which the characteristics of information shared in a catchment advice network are associated with adaptations. Statistical analyses reveal the perceived efficacy of communications as well as farmers’ relative closeness in the advice network to be positively associated with adaptation to drought. We identify a capacity for local actors to bridge information bottlenecks in the network and opportunities for institutions to enhance their dissemination of information to reach less networked farmers. We find that not all adaptations are perceived as effective against future drought and infer opportunities to support engagement with extension services, encourage the sharing of local knowledge and experience and devise policy and interventions to strengthen advice networks for more resilient agricultural systems. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.
{"title":"The contribution of a catchment-scale advice network to successful agricultural drought adaptation in Northern Thailand","authors":"D. Goodwin, I. Holman, C. Sutcliffe, G. Salmoral, Liwa Pardthaisong, S. Visessri, C. Ekkawatpanit, D. Rey","doi":"10.1098/rsta.2021.0293","DOIUrl":"https://doi.org/10.1098/rsta.2021.0293","url":null,"abstract":"The intensification of drought affects agricultural production, leading to economic losses, environmental degradation and social impacts. To move toward more resilient system configurations requires understanding the processes that shape farmers' adaptation amidst complex institutional contexts. Social networks are an important part of collective action for supporting adaptive capacity and there are continuing calls to strengthen network connectivity for agricultural governance under the impacts of climate change. Through a survey of 176 farmers in northern Thailand, we explore the extent to which the characteristics of information shared in a catchment advice network are associated with adaptations. Statistical analyses reveal the perceived efficacy of communications as well as farmers’ relative closeness in the advice network to be positively associated with adaptation to drought. We identify a capacity for local actors to bridge information bottlenecks in the network and opportunities for institutions to enhance their dissemination of information to reach less networked farmers. We find that not all adaptations are perceived as effective against future drought and infer opportunities to support engagement with extension services, encourage the sharing of local knowledge and experience and devise policy and interventions to strengthen advice networks for more resilient agricultural systems. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77768386","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}
The growing risk of water crises, including drought, is one of the greatest challenges in the coming decades. Averting such crises will be especially daunting, given that they are just as much a failure of water management as they are a result of scarcity. A major shortcoming is the persistent underpricing of water. The increasing environmental and social costs associated with freshwater scarcity are not routinely reflected in markets. Nor have we developed adequate policies and institutions to handle these costs. This creates perverse incentives that fail to balance water exttraction with supply, protect freshwater ecosystems and generate water-saving innovations. However, drought is proving to be a catalyst for governance and policy reform, and steps can be taken to overcome the underpricing of water. Several examples are explored to illustrate the economic challenge. They include removing the barriers to water markets and trading, reallocating subsidies for water supply and sanitation to expand delivery in developing countries and reforming environmentally harmful irrigation and agricultural policies. The article also explains how ending underpricing can foster a comprehensive strategy for water-saving innovation that can ‘bend’ the global water use curve. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.
{"title":"The economics of managing water crises","authors":"E. Barbier","doi":"10.1098/rsta.2021.0295","DOIUrl":"https://doi.org/10.1098/rsta.2021.0295","url":null,"abstract":"The growing risk of water crises, including drought, is one of the greatest challenges in the coming decades. Averting such crises will be especially daunting, given that they are just as much a failure of water management as they are a result of scarcity. A major shortcoming is the persistent underpricing of water. The increasing environmental and social costs associated with freshwater scarcity are not routinely reflected in markets. Nor have we developed adequate policies and institutions to handle these costs. This creates perverse incentives that fail to balance water exttraction with supply, protect freshwater ecosystems and generate water-saving innovations. However, drought is proving to be a catalyst for governance and policy reform, and steps can be taken to overcome the underpricing of water. Several examples are explored to illustrate the economic challenge. They include removing the barriers to water markets and trading, reallocating subsidies for water supply and sanitation to expand delivery in developing countries and reforming environmentally harmful irrigation and agricultural policies. The article also explains how ending underpricing can foster a comprehensive strategy for water-saving innovation that can ‘bend’ the global water use curve. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80554881","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}
Pub Date : 2022-07-25Epub Date: 2022-06-06DOI: 10.1098/rsta.2021.0019
Seung Woo Lee, Shelley I Fried
Cortical visual prostheses that aim to restore sight to the blind require the ability to create neural activity in the visual cortex. Electric stimulation delivered via microelectrodes implanted in the primary visual cortex (V1) has been the most common approach, although conventional electrodes may not effectively confine activation to focal regions and thus the acuity they create may be limited. Magnetic stimulation from microcoils confines activation to single cortical columns of V1 and thus may prove to be more effective than conventional microelectrodes, but the ability of microcoils to drive synaptic connections has not been explored. Here, we show that magnetic stimulation of V1 using microcoils induces spatially confined activation in the secondary visual cortex (V2) in mouse brain slices. Single-loop microcoils were fabricated using platinum-iridium flat microwires, and their effectiveness was evaluated using calcium imaging and compared with that of monopolar and bipolar electrodes. Our results show that compared to the electrodes, the microcoils better confined activation to a small region in V1. In addition, they produced more precise and sustained activation in V2. The finding that microcoil-based stimulation propagates to higher visual centres raises the possibility that complex visual perception, e.g. that requiring sustained synaptic inputs, may be achievable. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.
{"title":"Micro-magnetic stimulation of primary visual cortex induces focal and sustained activation of secondary visual cortex.","authors":"Seung Woo Lee, Shelley I Fried","doi":"10.1098/rsta.2021.0019","DOIUrl":"10.1098/rsta.2021.0019","url":null,"abstract":"<p><p>Cortical visual prostheses that aim to restore sight to the blind require the ability to create neural activity in the visual cortex. Electric stimulation delivered via microelectrodes implanted in the primary visual cortex (V1) has been the most common approach, although conventional electrodes may not effectively confine activation to focal regions and thus the acuity they create may be limited. Magnetic stimulation from microcoils confines activation to single cortical columns of V1 and thus may prove to be more effective than conventional microelectrodes, but the ability of microcoils to drive synaptic connections has not been explored. Here, we show that magnetic stimulation of V1 using microcoils induces spatially confined activation in the secondary visual cortex (V2) in mouse brain slices. Single-loop microcoils were fabricated using platinum-iridium flat microwires, and their effectiveness was evaluated using calcium imaging and compared with that of monopolar and bipolar electrodes. Our results show that compared to the electrodes, the microcoils better confined activation to a small region in V1. In addition, they produced more precise and sustained activation in V2. The finding that microcoil-based stimulation propagates to higher visual centres raises the possibility that complex visual perception, e.g. that requiring sustained synaptic inputs, may be achievable. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.</p>","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"380 1","pages":"20210019"},"PeriodicalIF":0.0,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11493182/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77209384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wireless interfaces enable brain-implanted devices to remotely interact with the external world. They are critical components in modern research and clinical neurotechnologies and play a central role in determining their overall size, lifetime and functionality. Wireless interfaces use a wide range of modalities—including radio-frequency fields, acoustic waves and light—to transfer energy and data to and from an implanted device. These forms of energy interact with living tissue through distinct mechanisms and therefore lead to systems with vastly different form factors, operating characteristics, and safety considerations. This paper reviews recent advances in the development of wireless interfaces for brain neurotechnologies. We summarize the requirements that state-of-the-art brain-implanted devices impose on the wireless interface, and discuss the working principles and applications of wireless interfaces based on each modality. We also investigate challenges associated with wireless brain neurotechnologies and discuss emerging solutions permitted by recent developments in electrical engineering and materials science. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.
{"title":"Wireless interfaces for brain neurotechnologies","authors":"Han-Joon Kim, J. S. Ho","doi":"10.1098/rsta.2021.0020","DOIUrl":"https://doi.org/10.1098/rsta.2021.0020","url":null,"abstract":"Wireless interfaces enable brain-implanted devices to remotely interact with the external world. They are critical components in modern research and clinical neurotechnologies and play a central role in determining their overall size, lifetime and functionality. Wireless interfaces use a wide range of modalities—including radio-frequency fields, acoustic waves and light—to transfer energy and data to and from an implanted device. These forms of energy interact with living tissue through distinct mechanisms and therefore lead to systems with vastly different form factors, operating characteristics, and safety considerations. This paper reviews recent advances in the development of wireless interfaces for brain neurotechnologies. We summarize the requirements that state-of-the-art brain-implanted devices impose on the wireless interface, and discuss the working principles and applications of wireless interfaces based on each modality. We also investigate challenges associated with wireless brain neurotechnologies and discuss emerging solutions permitted by recent developments in electrical engineering and materials science. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87653343","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}
Neuron and neural network studies are remarkably fostered by novel stimulation and recording systems, which often make use of biochips fabricated with advanced electronic technologies and, notably, micro- and nanoscale complementary metal-oxide semiconductor (CMOS). Models of the transduction mechanisms involved in the sensor and recording of the neuron activity are useful to optimize the sensing device architecture and its coupling to the readout circuits, as well as to interpret the measured data. Starting with an overview of recently published integrated active and passive micro/nanoelectrode sensing devices for in vitro studies fabricated with modern (CMOS-based) micro-nano technology, this paper presents a mixed-mode device-circuit numerical-analytical multiscale and multiphysics simulation methodology to describe the neuron-sensor coupling, suitable to derive useful design guidelines. A few representative structures and coupling conditions are analysed in more detail in terms of the most relevant electrical figures of merit including signal-to-noise ratio. This article is part of the theme issue ‘Advanced neurotechnologies: translating innovation for health and well-being’.
{"title":"Multiscale simulation analysis of passive and active micro/nanoelectrodes for CMOS-based in vitro neural sensing devices","authors":"Federico Leva, P. Palestri, L. Selmi","doi":"10.1098/rsta.2021.0013","DOIUrl":"https://doi.org/10.1098/rsta.2021.0013","url":null,"abstract":"Neuron and neural network studies are remarkably fostered by novel stimulation and recording systems, which often make use of biochips fabricated with advanced electronic technologies and, notably, micro- and nanoscale complementary metal-oxide semiconductor (CMOS). Models of the transduction mechanisms involved in the sensor and recording of the neuron activity are useful to optimize the sensing device architecture and its coupling to the readout circuits, as well as to interpret the measured data. Starting with an overview of recently published integrated active and passive micro/nanoelectrode sensing devices for in vitro studies fabricated with modern (CMOS-based) micro-nano technology, this paper presents a mixed-mode device-circuit numerical-analytical multiscale and multiphysics simulation methodology to describe the neuron-sensor coupling, suitable to derive useful design guidelines. A few representative structures and coupling conditions are analysed in more detail in terms of the most relevant electrical figures of merit including signal-to-noise ratio. This article is part of the theme issue ‘Advanced neurotechnologies: translating innovation for health and well-being’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84047766","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}
Gabriel P. Lachance, Élodie Boisselier, Mounir Boukadoum, A. Miled
Neurotransmitter sensing in the brain is crucial for the understanding of neuro-degenerative diseases. Most modern methods for the purpose rely on bulky instruments or are disruptive to the neurotransmitter medium. In this work, we describe and evaluate the design of a novel, compact and non-invasive instrument for neurotransmitter detection based on the colorimetric sensing method. The instrument includes a grism-based spectrometer that measures the wavelength shift of gold nanoparticles that are functionalized with aptamers to act as neurotransmitter-specific markers. It also includes microfluidic and electronic subsystems for sample preparation and control, and processing of the obtained signal. The instrument is tested with gold nanoparticles and its performance is compared to that of a commercial instrument, showing that the designed prototype matches the commercial instrument in performance while being much smaller, and it can surpass it with further improvements. This article is part of the theme issue ‘Advanced neurotechnologies: translating innovation for health and well-being’.
{"title":"Towards an advanced neurotechnological system: colorimetric sensing with a novel grism-based spectrometer, functionalized gold nanoparticles and a heterogeneous embedded system","authors":"Gabriel P. Lachance, Élodie Boisselier, Mounir Boukadoum, A. Miled","doi":"10.1098/rsta.2021.0016","DOIUrl":"https://doi.org/10.1098/rsta.2021.0016","url":null,"abstract":"Neurotransmitter sensing in the brain is crucial for the understanding of neuro-degenerative diseases. Most modern methods for the purpose rely on bulky instruments or are disruptive to the neurotransmitter medium. In this work, we describe and evaluate the design of a novel, compact and non-invasive instrument for neurotransmitter detection based on the colorimetric sensing method. The instrument includes a grism-based spectrometer that measures the wavelength shift of gold nanoparticles that are functionalized with aptamers to act as neurotransmitter-specific markers. It also includes microfluidic and electronic subsystems for sample preparation and control, and processing of the obtained signal. The instrument is tested with gold nanoparticles and its performance is compared to that of a commercial instrument, showing that the designed prototype matches the commercial instrument in performance while being much smaller, and it can surpass it with further improvements. This article is part of the theme issue ‘Advanced neurotechnologies: translating innovation for health and well-being’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"78 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88914173","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}
Life and the genetic code are self-referential and so are autocatalytic networks made of simpler, small molecules. Several origins of life theories postulate autocatalytic chemical networks preceding the primordial genetic code, yet demonstration with biochemical systems is lacking. Here, small-molecule reflexively autocatalytic food-generated networks (RAFs) ranging in size from 3 to 619 reactions were found in all of 6683 prokaryotic metabolic networks searched. The average maximum RAF size is 275 reactions for a rich organic medium and 93 for a medium with a single organic cofactor, NAD. In the rich medium, all universally essential metabolites are produced with the exception of glycerol-1-p (archaeal lipid precursor), phenylalanine, histidine and arginine. The 300 most common reactions, present in at least 2732 RAFs, are mostly involved in amino acid biosynthesis and the metabolism of carbon, 2-oxocarboxylic acid and purines. ATP and NAD are central in generating network complexity, and because ATP is also one of the monomers of RNA, autocatalytic networks producing redox and energy currencies are a strong candidate niche of the origin of a primordial information-processing system. The wide distribution of small-molecule autocatalytic networks indicates that molecular reproduction may be much more prevalent in the Universe than hitherto predicted. This article is part of the theme issue 'Emergent phenomena in complex physical and socio-technical systems: from cells to societies'.
{"title":"Small-molecule autocatalytic networks are universal metabolic fossils","authors":"Joana C. Xavier, S. Kauffman","doi":"10.1098/rsta.2021.0244","DOIUrl":"https://doi.org/10.1098/rsta.2021.0244","url":null,"abstract":"Life and the genetic code are self-referential and so are autocatalytic networks made of simpler, small molecules. Several origins of life theories postulate autocatalytic chemical networks preceding the primordial genetic code, yet demonstration with biochemical systems is lacking. Here, small-molecule reflexively autocatalytic food-generated networks (RAFs) ranging in size from 3 to 619 reactions were found in all of 6683 prokaryotic metabolic networks searched. The average maximum RAF size is 275 reactions for a rich organic medium and 93 for a medium with a single organic cofactor, NAD. In the rich medium, all universally essential metabolites are produced with the exception of glycerol-1-p (archaeal lipid precursor), phenylalanine, histidine and arginine. The 300 most common reactions, present in at least 2732 RAFs, are mostly involved in amino acid biosynthesis and the metabolism of carbon, 2-oxocarboxylic acid and purines. ATP and NAD are central in generating network complexity, and because ATP is also one of the monomers of RNA, autocatalytic networks producing redox and energy currencies are a strong candidate niche of the origin of a primordial information-processing system. The wide distribution of small-molecule autocatalytic networks indicates that molecular reproduction may be much more prevalent in the Universe than hitherto predicted. This article is part of the theme issue 'Emergent phenomena in complex physical and socio-technical systems: from cells to societies'.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75017419","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}
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