Dynamic Maintenance Research Articles

Research and Evaluation on Dynamic Maintenance of an Elevation Datum Based on CORS Network Deformation

This paper presents a method for dynamically maintaining a regional elevation datum using CORS stations as core nodes. By utilizing CORS station data and surface mass loading data (including land water storage, sea level, and atmospheric pressure), the normal height changes of each station can be determined and dynamically maintained. The validity of this method is verified using multiple leveling survey results from five CORS stations in Beijing’s subsidence area between January 2012 and June 2021. Results show that it is necessary to derive and correct the height anomaly variation of CORS stations caused by surface mass loading using the remove-calculate-restore method and the Green’s function integration method, with the influence of surface mass changes reaching a subcentimeter level. CORS stations exhibiting great observation quality achieve a mean accuracy of 2.7 mm in determining normal height changes. Such accuracy surpasses the requirements of second-class leveling surveys covering route lengths exceeding 1.35 km, as well as conforming/closed loop routes with distances greater than 0.46 km. By strategically selecting CORS stations with long-term continuous observations and high-quality data as core nodes within the elevation control network, dynamic maintenance of the regional elevation datum can be achieved based on CORS station data.

Role of A-Kinase Anchoring Protein 1 in Retinal Ganglion Cells: Neurodegeneration and Neuroprotection.

A-Kinase anchoring protein 1 (AKAP1) is a multifunctional mitochondrial scaffold protein that regulates mitochondrial dynamics, bioenergetics, and calcium homeostasis by anchoring several proteins, including protein kinase A, to the outer mitochondrial membrane. Glaucoma is a complex, multifactorial disease characterized by a slow and progressive degeneration of the optic nerve and retinal ganglion cells (RGCs), ultimately resulting in vision loss. Impairment of the mitochondrial network and function is linked to glaucomatous neurodegeneration. Loss of AKAP1 induces dynamin-related protein 1 dephosphorylation-mediated mitochondrial fragmentation and loss of RGCs. Elevated intraocular pressure triggers a significant reduction in AKAP1 protein expression in the glaucomatous retina. Amplification of AKAP1 expression protects RGCs from oxidative stress. Hence, modulation of AKAP1 could be considered a potential therapeutic target for neuroprotective intervention in glaucoma and other mitochondria-associated optic neuropathies. This review covers the current research on the role of AKAP1 in the maintenance of mitochondrial dynamics, bioenergetics, and mitophagy in RGCs and provides a scientific basis to identify and develop new therapeutic strategies that could protect RGCs and their axons in glaucoma.

Comparison of fine bubble scouring, backwash, and mass air load supply for dynamic membrane maintenance and steady operation in SFD MBR for wastewater treatment

The self-forming dynamic membrane bioreactor (SFD MBR) is an evolution of the conventional ultrafiltration-based MBR where filtration occurs through a cake layer (dynamic membrane, DM) supported by a filtration net. The effluent quality levels that may be achieved through this technology are comparable to those of conventional MBR and suitable for effluent reuse, as shown in previous research. In addition, SFD MBR are more sustainable, both in terms of investment costs (filtration net materials are cheaper than UF membranes), and operation. Indeed, the typical operating pressure of these systems is below 100 mbar, thus compatible with gravity-driven operation. Nevertheless, as all membrane-based processes, also SFD MBR require periodic maintenance cleaning of the supports holding the filtering layers, in order to ensure high and constant effluent quality and steady operation. In this paper, different strategies for continuous or temporized cyclic DM maintenance aimed at limiting the frequency of on-site manual cleaning interventions are compared. In particular, five tests were performed at the bench scale adopting the same process conditions except for the type of DM maintenance strategy. Continuous fine-bubble air scouring of the membrane surface was compared with two intermittent cyclic procedures based on backwash with permeate (with and without simultaneous air scouring) and mass air load supply (with two cycles of different durations), respectively. The results have confirmed the overall high performance of this technology under all the tested conditions, with COD removal efficiencies always exceeding 86 %, effluent turbidity values normally well below 5 NTU (and often much lower), complete nitrification and partial nitrogen removal. Furthermore, the comparison among the different DM maintenance strategies has shown that the mass air load supply is the most efficient approach towards sustainable operation. In particular, shorter mass air load cycles provided the best performance in limiting the manual cleaning needs, which under this condition were as low as once every 3 weeks. The key finding of this study is the demonstration of cyclic air mass load as an effective preventive cleaning strategy allowing good performance of a bench-scale SFD MBR, strongly reducing the manual maintenance requirements. More experiments are required to confirm these results in larger scale installations.

A dynamic multi-layer maintenance service network evolution and decision-making method for service-oriented complex equipment

Nowadays, along with the development of smart product-service paradigm, the service-oriented complex equipment (SocE) that considers the proactive condition-based maintenance services integration and planning is drawing wide attentions. The traditional integrations focus on the static configuration processes and the dynamic decision-makings are mainly planned from end users. This blocks the smart service transformations for providers, and brings the improper service matching and selections with higher cost, response time or lower service qualities. To bridge this gap, the dynamic multi-layer maintenance service network evolution model and decision-making method are proposed. Firstly, the model focuses on the SocE and builds the dynamic service network. On basis of this network, the data-driven network evolution processes, evolution mechanisms and modeling flows are developed to fulfill the dynamic configuration, and thus to form the SocE. Secondly, combining with these configurated feasible services, the dynamic decision-making that considers activities and providers selections is developed with the network node characteristics. Finally, the experimental simulation and application cases are both displayed and discussed. It shows the feasibility and effectiveness of the proposed model and method.

Insights into Current Education of Acupuncture as a Non-Conventional Therapy in Portugal.

Acupuncture, as an ancient practice for healthcare in China, is now widely used in the world and regarded as a non-conventional therapy (NCT) in many Western countries. In Portugal, acupuncture has been structured and well regulated for the market of teaching and clinical practice, but little effort has been put in to explore it in depth. This article aims to disclose the current education of acupuncture as a NCT in Portugal through investigation of acupuncture laws, field surveys, teaching work, and interviews with people from the NCT field. We found that according to the academic norms and rules of education in Portugal, there is a gradual difficulty in the progression and maintenance of the degree training dynamics. The reasons are the lack of more tolerant transitional measures and many practical difficulties confronted by the institutions that embark on these complementary programs. Therefore, it will be necessary to promote additional programs and measures to avoid a total emptiness of the teaching of acupuncture and at the same time losses of clinicians, competencies, and quality of information that are difficult to recover. It could be very meaningful and thought provoking to the future development and improvement of acupuncture in Portugal and in other countries that welcome acupuncture and intend to have better legislation and application.

Maintenance planning innovation: realising planning and execution efficiencies through process and digital transformation

As oil and gas facilities age, the need to allocate finite planning effort across mounting scopes of work increases. Woodside has tackled this problem head-on, seeking innovative solutions to reduce waste in deploying low-complexity asset maintenance. Through its Accelerator Programme, Woodside has employed new capabilities – such as enterprise design thinking and agile at scale delivery – conducting over 200 interviews and prototype tests to deeply understand maintenance priorities and identify opportunities to realise value, organisation wide. The result is an in-house scope management application, which supports the end-to-end maintenance planning workflow. The application considers multiple data points on thousands of work orders in seconds, using a sophisticated algorithm to incorporate industry knowledge and business priorities specific to Woodsides’ needs. The application produces a maintenance plan optimised by understanding location, equipment and process efficiency drivers to ensure the best utilisation of resources. The embedding of intelligent automation represents a cultural shift, enabling a move towards a more dynamic maintenance planning process that responds to changing asset priorities. Currently, 41% of all North-West Shelf Gas Project scopes are managed through the application. A 95% reduction in selection time and a 90% reduction in overall planning duration have been realised from this initiative. By releasing valuable planning effort back to the business to focus on complex scope, Woodside can realise and maintain safe, reliable and efficient operations in a low-cost, variable environment.

Dynamic path planning of intelligent robot in power equipment maintenance environment

Aiming at the problem that the traditional path planning algorithm does not have real-time planning performance in the dynamic and complex power equipment maintenance environment, or it is challenging to avoid dynamic obstacle obstacles due to poor real-time version, this paper proposes an artificial potential field method for real-time planning. The characteristics of dynamic obstacle in a dynamic complex environment, the dynamic obstacles are simplified as moving particles, and the repulsion function of the dynamic obstacles is added to avoid the collision. Within the influence range of dynamic obstacles in a busy complex environment, the robot avoids the dynamic obstacles through real-time local path planning under the influence of the repulsive force of the dynamic obstacle to reach the target point. At the same time, aiming at the problems of unevenness and fluctuation of the path generated by the traditional artificial potential field method, the non-uniform rational B-spline and moving average filtering algorithm are used to improve the local path planning algorithm of the conventional artificial potential field, and the generated path is smoother and smoother than the traditional algorithm.

Designing two-level rescue depot location and dynamic rescue policies for unmanned vehicles

Unmanned vehicles are often required to execute critical missions in harsh environment, causing system failure which may occur during the mission execution or rescue procedure. Existing research has focused primarily on policies during mission execution to reduce failure risk. The paper investigates risk evaluation and control policies both in the mission execution and rescue phases, and proposes two-level rescue depot location policies and dynamic rescue policies including mission abort and maintenance policies for unmanned vehicle systems. Specifically, considering multi-state characteristics of unmanned vehicle systems, two-level rescue depots are introduced to satisfy maintenance demands by providing different types of maintenance. To improve survivability in the mission execution, dynamic mission abort policies are executed when the number of failed components reaches predetermined thresholds, and then a rescue procedure is initiated. During the rescue, elaborate designed rescue depots location and dynamic maintenance policies are developed to reduce the risk of failure in the rescue. After a successful rescue, unmanned vehicles can re-attempt missions. The recursive algorithm and discretization algorithm are used to derive and evaluate mission success probability, system survivability, and expected cost of losses, and optimization models based on three indicators are formulated. The superiority of the proposed policies is demonstrated by a case study of a UAV system.

Adoption of prescriptive analytics for naval vessels risk-based maintenance:A conceptual framework

Prescriptive analytics is a novel maintenance approach by recommending the maintainer, the right maintenance action at the right time through prioritization of maintenance based on the risk. It assists in improving the existing preventive maintenance approach by offering a dynamic maintenance plan based on risk or Risk-based Maintenance Scheduling. To date, there is no clear definition of Naval Vessels Risk-based Maintenance as well as its framework, and it has not been applied extensively in naval vessel maintenance application which is peculiar compared to its application in plant maintenance. This paper reviews Risk-based Maintenance application in industries in an approach to develop prescriptive analytics for a comprehensive and dynamic naval vessels Risk-based Maintenance decision-making framework. It aims to establish an optimal maintenance scheduling to improve naval vessels availability and reduce maintenance costs while meeting stakeholders’ expectations. Objectives and considerations are also defined for peculiarities application of naval vessels. The framework is then evaluated to improve the effectiveness of the current Preventive Maintenance practice and the inconsistency of the existing maintenance decision-making model using the expert judgement in Reliability Centered Maintenance.

Dynamic maintenance planning for autonomous marine systems (AMS) and operations

Compared to conventional marine systems, where the onboard crew can perform frequent and flexible maintenance, autonomous marine systems (AMS) only involve a limited (or, even no) crew during a voyage, and this challenges maintenance planning and execution. The current study identifies the relevant issues and proposes to solve these through developing a dynamic maintenance planning method for AMS. By considering economical dependencies among components, the study presents a dynamic grouping method to determine the optimum maintenance opportunities for AMS in the future. Stochastic dependencies of components are considered by using the Markov model. A multiphase Markov model is proposed for modeling stochastic dependencies between components where the limited and irregular maintenance opportunities are handled by the multiphase part of the model. A heuristic method is proposed to deal with the combinatorial challenge.To demonstrate the application of the proposed method, the maintenance planning of a cooling system of an autonomous ship is performed in a case study. To validate its performance, the proposed heuristic method is compared with existing ‘short-sighted’ methods for a selection of candidate groups for maintenance. In the validation, various scenarios with different component states and maintenance strategies are tested.

143 Elucidating the Function of the Wnt Signaling Pathway in Hydrocephalus

INTRODUCTION: Although acquired hydrocephalus is commonly encountered by neurosurgeons, our understanding of the mechanisms underlying its pathogenesis remain poor. Furthermore, normal CSF physiology is dependent on the proper function of ventricular ependymal cells and choroid plexus epithelium (CPE), although few neurosurgical studies have addressed the functions of these cells. METHODS: Alteration of the Wnt pathway is achieved by generating FoxJ1-Cre;Apclox/lox and FoxJ1-Cre;Ctnnb1lox/lox mice, which express Cre upon induction with tamoxifen, as well as via intraventricular delivery of an AAV1-eGFP-Cre in Apclox/lox and Ctnnb1lox/lox mice. T2 weighted MRI with 3D volumetrics is applied to assess ventricular anatomy, in addition to standard molecular biology techniques to examine downstream signaling mechanisms. Kaolin and whole blood injection are used as models of obstructive and communicating hydrocephalus, respectively. RESULTS: B-catenin is strongly expressed in adult mouse ependyma and CPE, suggesting that the canonical Wnt pathway continues to be active after these cells have developed. Moreover, up-regulation of this pathway in adult FoxJ1-Cre;Apclox/lox mice results in significant ventricular enlargement (n = 3; p = 0.03). Both FoxJ1-Cre transgenic mice and intraventricular AAV1-eGFP-Cre drive selective expression within ependyma and CPE, suggesting that these may be useful models for investigating important molecular pathways within these cells. CONCLUSIONS: Our data suggests that the canonical Wnt signaling pathway plays a role in the maintenance of normal adult CSF dynamics. Moreover, we show selective targeting of ependyma and CPE using an adeno-associated virus, which may represent a novel strategy for modifying genes and/or proteins involved in CSF regulation.

A bio-inspired LIDA cognitive-based Digital Twin architecture for unmanned maintenance of machine tools

Affected by COVID-19, the maintenance process of machine tools is significantly hindered, while unmanned maintenance becomes an emerging trend in such background. So far, three challenges, namely, the dependence on maintenance experts, the dynamic maintenance environments, and unsynchronized interactions between physical and information sides, exist as the main obstacles in its widespread applications. In order to fill this gap, a bio-inspired LIDA cognitive-based Digital Twin architecture is proposed, so as to achieve unmanned maintenance of machine tools through a self-constructed, self-evaluated, and self-optimized manner. A three phases process in the architecture, including the physical phase, virtual phase, and service phase, is further introduced to support the cognitive cycle for unmanned maintenance of machine tools. An illustrative example is depicted in the unmanned fault diagnosis on the rolling bearing of a drilling platform, which validates the feasibility and advantages of the proposed architecture. As an explorative study, it is wished that this work provides useful insights for unmanned maintenance of machine tools in a dynamic production environment.

Clustering-based Active Learning Classification towards Data Stream

Many practical applications, such as social media and monitoring system, will constantly generate streaming data, which has problems of instability, lack of labels and multiclass imbalance. In order to solve these problems, a cluster-based active learning method is proposed to achieve data stream classification. Firstly, a label query strategy combining marginal threshold matrix is proposed, which selects difficult to classify or potential concept drift samples for marking, to solve the problem of high cost label and unbalanced data. Secondly, dynamic maintenance of a group of micro clusters, by adjusting the weight of micro clusters in the model, correctly reflects the current data distribution, and finally, uses the buffer to store new micro clusters to participate in the update of the model, to adapt to the new data environment. Experimental results on three real data sets and three synthetic data sets show that compared with the classical data stream classification algorithm, it is less affected by concept drift and has higher classification accuracy than the online semi-supervised learning algorithm ADSM. The average accuracy of the six datasets increased by 5.56%, 2.32%, 1.77%, 1.83%, 3.78%, and 2.04%, respectively. The model processes data streams online and improves classification performance with less memory consumption.

Dynamic Construction and Maintenance of Confined Nanoregions via Hydrogen-Bond Networks between Acetylene Reactants and a Polyoxometalate-Based Metal-Organic Framework.

The nanoconfinement effect in catalysis has attracted much attention because it provides a novel means of regulating the molecular properties and related reactions. Confined nanoregions composed of both reactants and catalysts through weak interactions are expected to improve the catalytic performance and promote the mass transport of relevant molecules simultaneously. However, at reaction temperatures, the structural variation of such confined spaces constructed via weak interactions remains unclear. Herein, through density functional theory calculations combined with ab initio molecular dynamics simulations, we have systematically investigated the dynamic structural evolution of the confined space constructed by acetylene reactants and a polyoxometalate-based metal-organic framework (POMOF) via hydrogen-bond networks. It is found that, at the reaction temperature of acetylene semihydrogenation, the hydrogen-bond networks and generated confined nanoregions are not rigid but are constantly changing and dynamically maintained. The steering role played by the O atoms at the surfaces of the polyoxometalate clusters is essential for generation of the hydrogen-bond networks and maintenance of the nanoregions. Upon confinement, the acetylene reactants can be better activated than those in an unconstrained atmosphere, which is reflected by the different dynamic distributions of the ∠CHC bending magnitude. Moreover, from a comparison of the distinct interaction characteristics between acetylene/ethylene and POMOF, the different manifestations in the adsorption energy variations of the confined molecules can be interpreted. This work helps to elucidate the underlying mechanisms of confined catalysis and may promote its application in practical catalytic processes.

Mobile and Self-Sustained Data Storage in an Extremophile Genomic DNA.

DNA has been pursued as a novel biomaterial for digital data storage. While large-scale data storage and random access have been achieved in DNA oligonucleotide pools, repeated data accessing requires constant data replenishment, and these implementations are confined in professional facilities. Here, a mobile data storage system in the genome of the extremophile Halomonas bluephagenesis, which enables dual-mode storage, dynamic data maintenance, rapid readout, and robust recovery. The system relies on two key components: A versatile genetic toolbox for the integration of 10-100kb scale synthetic DNA into H. bluephagenesis genome and an efficient error correction coding scheme targeting noisy nanopore sequencing reads. The storage and repeated retrieval of 5KB data under non-laboratory conditions are demonstrated. The work highlights the potential of DNA data storage in domestic and field scenarios, and expands its application domain from archival data to frequently accessed data.

Research on preventive maintenance strategy of Coating Machine based on dynamic failure rate

In this paper, a dynamic preventive maintenance strategy is proposed for the problem of high maintenance cost rate due to excessive maintenance caused by unreasonable maintenance threshold setting when complex electromechanical equipment maintenance strategy is formulated. Increasing failure rate factor and decreasing service age factor are introduced to describe the evolution rules of failure rate during the maintenance of the coating machine, and the BP-LSTM (BP-Long Short Term Memory Network, BP-LSTM) model is combined to predict the failure rate of the coating machine. A Dynamic preventive maintenance Model (DM) that relies on dynamic failure rate thresholds to classify the three preventive maintenance modes of minor, medium and major repairs is constructed. A dynamic preventive maintenance strategy optimization process based on Genetic-Particle Swarm Optimization (GPSO) algorithm with the lowest cost rate per unit time in service phase is built to solve the difficult problem of dynamic failure rate threshold finding. Based on the historical operating data of the coating machine, a case study of the dynamic preventive maintenance strategy of the coating machine was conducted to verify the effectiveness of the model and the developed maintenance strategy proposed in this paper. The results show that the maintenance strategy developed in this paper can ensure better economy and applicability.

Plant Toxins as Potential Alternatives to Botulinum Toxin for Eye-Movement Disorder Therapy

The most successful alternative to traditional surgery for ocular muscle spasm treatment is the intramuscular injection of botulinum toxin (BTX), which allows the maintenance of the muscle dynamics and the absence of scars. However, the main BTX disadvantage is its nonpermanent effect. A possible way for overcoming this obstacle could be represented by the enzymatic surgery using plant toxins known as ribosome-inactivating proteins (RIPs). In this paper, two highly toxic RIPs, namely, ricin and stenodactylin, were considered in a preliminary study for their possible use in the treatment of strabismus and oculofacial dystonias, as alternatives to BTX. Both RIPs showed a strong cytotoxic effect against rhabdomyosarcoma cell lines and myotube differentiated cells, with stenodactylin being about 10-fold more toxic than ricin. Moreover, stenodactylin showed a much higher cytotoxicity on myoblasts than on rhabdomyosarcoma cells. In our experimental conditions, stenodactylin did not damage conjunctival cells. Despite the limitations due to in vitro experiments, our data show that the high cytotoxicity of stenodactylin allows the use of a very low dose and, consequently, of very low injection volumes. This can represent a great advantage in the case of in vivo locoregional treatment. Furthermore, it is possible to modulate the chemoablation of myocytes while destroying myoblasts, thus reducing regenerative phenomena. The risk of cytotoxicity to surrounding tissues would be strongly reduced by the low injected volume and the relative resistance of conjunctival cells. In conclusion, our data suggest that stenodactylin and ricin could represent potential candidates to substitute BTX in ocular dystonia therapy.

Genomic mechanisms controlling renal vitamin D metabolism

Vitamin D metabolism centers on regulation in the kidney of CYP27B1 induction by PTH, suppression by FGF23 and 1,25(OH)2D3, and reciprocal CYP24A1 suppression by PTH, and induction by FGF23 and 1,25(OH)2D3. This coordinated genomic regulation through enhancer modules results in the production and dynamic maintenance of circulating endocrine 1,25(OH)2D3 which, together with PTH and FGF23, controls mineral homeostasis. We discovered enhancers near Cyp27b1 in the mouse kidney located within intronic regions of Mettl1 and Mettl21b genes. These kidney-specific enhancers (“M1”, “M21”) control Cyp27b1. Through CRISPR/Cas deletion, we found that PTH activation of Cyp27b1 is lost with deletion of M1, whereas FGF23 suppression is lost with deletion of M21. The combination of both deletions (M1/M21-DIKO) eliminated the suppression by 1,25(OH)2D3. Cyp24a1 activation by 1,25(OH)2D3 is controlled by a promoter proximal pair of VDREs as well as a distal region − 35 to − 37 kb (DS2). We also found that FGF23 activation and PTH suppression of Cyp24a1 was located in a region − 21 to − 37 kb downstream (DS1). More recently, using in vivo ChIP-seq in mouse kidney, we demonstrate that PTH activation rapidly induces increased recruitment of pCREB and its coactivators, CBP and CRTC2, to the M1 and M21 enhancers near the Cyp27b1 gene. At distal enhancers of the Cyp24a1 gene, PTH suppression promotes dismisses CBP with only minor changes in pCREB and CRTC2 occupancy, all of which correlate with a suppression of basal histone acetylation across this locus and reduced transcripts. Surprisingly, we find that 1,25(OH)2D3 suppression increases the occupancy of CRTC2 in the M1 enhancer, a novel observation for CRTC2 and/or 1,25(OH)2D3 action. The suppressive actions of 1,25(OH)2D3 and FGF23 at the Cyp27b1 gene are associated with a reduction in CBP recruitment at these enhancers. Although FGF23-regulated transcription factors remain unknown, we hypothesize that VDR occupancy induced at the M1 and M21 enhancers by 1,25(OH)2D3 likely disrupts or competes with the active conformation of these CREB modules thereby preventing full induction by PTH. Our findings show coactivators such as CRTC2 and CBP contribute to Cyp27b1 and Cyp24a1 transcription and provide molecular insight into the coordinated mechanistic actions of PTH, FGF23, and 1,25(OH)2D3 in the kidney that regulate mineral homeostasis.

Inversion of Regional Groundwater Storage Changes Based on the Fusion of GNSS and GRACE Data: A Case Study of Shaanxi–Gansu–Ningxia

This paper aims to address the limitations of the distribution number and uniformity of Continuously Operating Reference Stations (CORS) and their impact on the reliability of inverting regional groundwater storage (GWS) based on Green’s function method and using global navigation satellite system (GNSS) data. A fusion method on the inversion of regional GWS changes from GNSS and the Gravity Recovery and Climate Experiment (GRACE) was proposed in this paper. Taking the Shaanxi–Gansu–Ningxia (SGN) region as an example, the in situ groundwater level data from ten CORS stations and eight wells were used for test analyses. In this paper, an atmospheric pressure model from the European Centre for Medium-Range Weather Forecasts (ECMWF), a global land data assimilation system (GLDAS), a WaterGAP global hydrology model (WGHM), and mean sea level anomaly (MSLA) data were used to quantitatively monitor the influence of vertical deformation caused by non-tidal environmental load. After deducing these loading deformations from the filtered time series of non-linear monthly geodetic height from the GNSS, the GWS changes in the SGN region from 2011 to 2014 were inverted. Meanwhile, the change in surface water storage from the GLDAS and WGHM models were removed from the terrestrial water storage (TWS) changes derived from GRACE. On this basis, the remove–restore theory in the Earth’s gravity field was introduced to both fuse the inversion results and obtain the regional GWS changes based on the fusion method. The results showed the following: (1) The local characteristics from the fusion results were more prominent than those of GRACE on the spatial scale, such as in the southwest and northeast in the study area. In addition, the fusion results were more uniform than those from GNSS, especially for the sparse and missing areas in which CORS stations were located, and the local effect was weakened. (2) On the time scale, compared with GRACE, the trends in GWS changes obtained from the fusion method and from GNSS inversion were roughly the same as the in situ groundwater level changes. (3) For the in situ groundwater wells “6105010031” and “6101260010”, the correlation coefficients of the fusion result were 0.53 and 0.56, respectively. The accuracy of the fusion method was slightly higher than that from GNSS, which indicates that the fusion method may be more effective for areas where CORS stations are missing or sparsely distributed. The methods in this paper can provide significant reference material for hydrodynamic research, sustainable management of water resources, and the dynamic maintenance of height data.

Exercise preserves physical fitness during aging through AMPK and mitochondrial dynamics

Exercise is a nonpharmacological intervention that improves health during aging and a valuable tool in the diagnostics of aging-related diseases. In muscle, exercise transiently alters mitochondrial functionality and metabolism. Mitochondrial fission and fusion are critical effectors of mitochondrial plasticity, which allows a fine-tuned regulation of organelle connectiveness, size, and function. Here we have investigated the role of mitochondrial dynamics during exercise in the model organism Caenorhabditis elegans. We show that in body-wall muscle, a single exercise session induces a cycle of mitochondrial fragmentation followed by fusion after a recovery period, and that daily exercise sessions delay the mitochondrial fragmentation and physical fitness decline that occur with aging. Maintenance of proper mitochondrial dynamics is essential for physical fitness, its enhancement by exercise training, and exercise-induced remodeling of the proteome. Surprisingly, among the long-lived genotypes we analyzed (isp-1,nuo-6, daf-2, eat-2, and CA-AAK-2), constitutive activation of AMP-activated protein kinase (AMPK) uniquely preserves physical fitness during aging, a benefit that is abolished by impairment of mitochondrial fission or fusion. AMPK is also required for physical fitness to be enhanced by exercise, with our findings together suggesting that exercise may enhance muscle function through AMPK regulation of mitochondrial dynamics. Our results indicate that mitochondrial connectivity and the mitochondrial dynamics cycle are essential for maintaining physical fitness and exercise responsiveness during aging and suggest that AMPK activation may recapitulate some exercise benefits. Targeting mechanisms to optimize mitochondrial fission and fusion, as well as AMPK activation, may represent promising strategies for promoting muscle function during aging.