The use of Bluetooth Low Energy (BLE) in the Internet-of-Things (IoT) applications has become widespread and popular. This has resulted in the increased number of deployed BLE devices. To ensure energy efficiency, applications use connectionless communication where nodes broadcast information using advertisement messages. As the BLE devices compete for access to spectrum, collisions are inevitable and methods that improve device coexistence are required. This paper proposes a connectionless communication scheme for BLE that improves communication efficiency in IoT applications where a large number of BLE nodes operate in the same area and communicate simultaneously to a central server. The proposed scheme is based on an active scanning mode and is compared with a typical application where passive scanning mode is used. The evaluation is based on numerical simulations and real-life evaluation of a network containing 150 devices. The presented scheme significantly reduces the number of messages transmitted by each node and decreases packet loss ratio. It also improves the energy efficiency and preserves the battery of BLE nodes as they transmit fewer radio messages and effectively spent less time actively communicating. The proposed connectionless BLE communication scheme can be applied to a large variety of IoT applications improving their performance and coexistence with other devices operating in the 2.4 GHz band. Additionally, the implementation complexity and costs of the proposed communication scheme are negligible. Bluetooth Low Energy (BLE) is a popular low-power radio communication technology available in contemporary smartphones, tablets and computers. Developed in the early 90 s, it has undergone significant changes and improvements. Among others, the current 5.2 version ,2,3 alloSo far, many authors  beca beca16])The proposed communication scheme aligns well with various approaches that aim to reduce the amount of data to be transmitted. For example, adaptive sampling allows to dynamically adapt sampling rate to the variability of the signal, and trade-off energy savings with data precision . The volexperimental evaluation of a large number of BLE devices operating in real-life environment in the presence of mutual and external interference, using connectionless communication for data transmission,results of numerical simulations to assess the impact of active scanning and suspending advertisements (upon reception of a scan request) on communication and energy efficiency,demonstration of the applicability of the connection-less active scanning BLE mode to large-scale opportunistic applications.This paper presents and evaluates the aforementioned BLE communication scheme using real-life experiments and numerical simulations. We analyse the impact of connectionless communication, active scanning and intermittent transmission on the performance of BLE communication. The contribution of this paper includes:The paper is organised as follows. Because the number of BLE devices using connection-based communication is limited ,20, the A number of papers focus on collisions in the communication channel, energy efficiency and node discovery delay, i.e., time from the first advertisement transmitted to the first time the scanner correctly receives one advertisement (but not necessarily the first one) and notices the presence of a node. This includes analyses of different versions of the BLE standard ,21, operAppropriate selection of BLE communication parameters allows to trade-off power consumption with device discovery delay and data throughput. Works by Shan et al. ,8 presenRenzel et al.  focused Further energy savings can be achieved if BLE radios are used only when needed and turned off otherwise. Venazi et al.  focused The article by Ghamari et al.  examinesConnectionless BLE communication is often used in opportunistic sensing applications ,5,26,27.BLE nodes can simultaneously work in connection-based and connectionless mode. Therefore, some papers address such scenarios, e.g., the article by Del Campo et al.  analysesPerez-Diaz De Cerio et al.  have anaAnother paper by the same authors  addresseThe communication scheme analysed in this paper benefits from connectionless BLE communication and active scanning. For simplicity we limit analysis to legacy advertising (as defined in BLE standard ) howeverIn connectionless communication mode the BLE nodes (advertisers) periodically broadcast advertisement (ADV) packets that can be coincidentally received by scanners. Depending on nodes and scanners configuration the devices may exchange either one or three radio messages .Single message mode (ADV only) is used when scanner operates in passive scanning mode or the node does not support scanning operation. Single message allows for unconfirmed, one way communication from the node to the scanners . Because the ADV message may contain up to 31 bytes of data, they can be used for application specific data transmission e.g., in opportunistic sensing applications ,5.Three message mode requires the scanner to operate in active scanning mode an the node to support scanning procedure. In three message mode the scanner may transmit the SCAN_REQ message after receiving the ADV. Frequency of SCAN_REQ depends on the content of the ADV received as well as a backoff procedure implemented in the scanner ,15. In gIn the proposed three message communication scheme  the SCANBecause the scanners run a backoff procedure before sending the SCAN_REQ message cf. ,16), the, the16])According to the BLE specification , the nodEfficiency of the proposed communication scheme was evaluated in a simulations and an experimental setup imitating a large scale opportunistic sensing application; a number of end-devices periodically transmit measurement data to a central unit using connectionless BLE communication. In such applications e.g., ,27) a la a la27])To model dense deployment we used 150 BLE devices broadcasting advertisements every 250 ms. The advertisement’s payload was 31 bytes including a sequence number that has changed every data interval The data were received by a scanner running in continuous scanning mode  in either active or passive mode, depending on the scenario. Because our goal was to imitate real-life sensing application we decided to use RaspberryPi (RPi) as scanners. These are low-cost and very popular devices with WiFi connectivity, integrated BLE radios  or supporting BLE dongles (RPi 3 and earlier). Because RPis are quite limited in computational and communication performance, the results of our experiments can be considered as a lower bound of what can be expected if more efficient scanners are used. The scanners were storing measurements in random-access memory to minimize the impact of the operating system and SD card underperformance on the results of the experiments.As part of the preparation for the actual experiments we have verified how different RPis perform as sniffers. These tests targeted assessment of different hardware setups  and configurations  on the communication performance. Based on the results we have used two sniffers (S1 and S2) running on RPi Zero W devices and operating in different modes depending on the test scenario . AdditioThe efficiency of the proposed scheme is assessed with Packet Loss Ratio (PLR) and Data Reception Ratio (DRR). The PLR is a measure that takes into account both the collisions in the communication channel as well as the underperformance of real-life scanners that may not be able to correctly receive all the packets, even if there is no collision in the radio channel. The PLR is calculated as a ratio of the number of ADV packets received by the scanner to the number transmitted by the advertising node. Because the scanner concurrently listens on a single advertisement channel, the PLR takes into account only ADV messages that are transmitted on the same channel. Therefore, the number of packets transmitted by a node  and is defined as the ratio of the number of received , and the nominator depending on the operation mode of the advertisers. For nodes in the continuous mode, the nominator equals the number of nodes from which ADV were successfully received by the scanner within data interval  through the comparison of advertisement reception by scanners. Scenarios 2 and 3 show the impact of the number of scanners operating in active scanning mode, while scenario 4 shows the effect of intermittent advertisement transmission.https://mariuszslabicki.github.io/pytooth/) to model behaviour of the BLE devices and analyse how intermittent mode affects communication efficiency compared to continuous transmission of advertisements. The model of the node and its operation is derived from the BLE specification [It is infeasible to estimate all parameters of interest in real-life experiments for different number of nodes operating in intermittent mode, and various settings of BLE parameters . Therefore, we have developed a simulator .Based on the results of the experiments we have estimated the expected values of DRRterval τ . The minSimulation analyses were done for two sets of scenarios : passiveSimulation results confirm real-life experiments. The results confirm that intermittent operation can maintain the same DRR while significantly lowering both the number of BLE messages transmitted and PLR values. Consequently, intermittent operation allows to improve coexistence and fair spectrum sharing with other networks, as BLE nodes and scanners exchange much less radio messages compared to passive scanning and continuous operation.eriments , Table 7eriments . In suchThe results of experiments and simulations show, that the use of active scanning and intermittent transmission allows to reduce communication overhead, collisions in the communication channel, and keep the DRR high even for small values of the data interval. This allows to transmit greater amounts of data within the same time (increase effective throughput), or rise the number of BLE nodes in the system.This article presents the benefits of using intermittent operation of BLE nodes in a typical IoT scenario, namely a dense network of large number of nodes, sensing and communicating periodically to the gateway. The real-life experiments with 150 nodes and thorough evaluation in simulation show that active scanning and intermittent operation of nodes can significantly reduce the number of BLE messages transmitted between the devices and lower the packet loss rate while all data is successfully transmitted. These improvements allow the battery-powered nodes to spend more time with radios disabled, preserve the energy and extend the lifetime. Less radio communications leaves more bandwidth to the other radios operating in a 2.4 GHz spectrum, thus becoming more fair in spectrum access. Moreover, because the nodes suspend transmission of ADV messages only after successful reception of SCAN_REQ, the proposed transmission scheme is immune to transient external interference including those caused by other radios consuming to much of the available bandwidth. The presented communication scheme follows the BLE specification and its implementation complexity is relatively small.


Large population studies such as the UK Biobank provide great opportunities for understanding the pathophysiology, health impact and prognostic factors associated with COVID-19, a condition that has had significant impact on almost everyone around the world. We highlight the vast opportunities, challenges and limitations for research and collaboration from the UK Biobank and other large population studies in helping us better understand and manage both current and potential future pandemics. Our knowledge of the disease is increasing at a fast pace and thus far has largely been from observational studies and registries  in 100,000 with a target completion in 2023 , 12. AlmThe number of UK Biobank participants scanned pre-COVID was under just below 50,000. The imaging centers stopped scanning participants on the 13th March due to COVID-19 and will resume scanning when deemed safe. Although only a 1/5 of the UK Biobank are planned to have imaging, it still provides detailed imaging information on 100,000 individuals which is substantial and unprecedented for any national biobank. Another advantage is the on-going rescanning effort which will enable the assessment of pre- and post-COVID changes.Follow-up health information is provided by robust linkage to primary care electronic health records, death and cancer registries and hospital admission records. With increasing outcome information generated over time the epidemiological opportunities of the UK Biobank study will be vast.The open source nature of the UK Biobank study is novel and therefore allow any researcher to benefit from the size and scope of the study through an application process. This is particularly commendable given longitudinal studies are notoriously expensive and logistically challenging to execute.With the COVID-19 pandemic affecting so many people, the UK Biobank study provides great opportunity for epidemiological analysis and allow us to explore characteristics that are associated with poorer outcomes in COVID-19 patients along with those that may be protective. The association of lifestyle, comorbidities, medication and phenotypic information with outcomes will become an invaluable source as more data becomes available on those that are tested for presence of COVID-19, especially as the UK government plans to ramp up targets for testing in the general population and not just those admitted to hospital or health care workers .Results of COVID-19 tests for UK Biobank participants are provided by Public Health England for participants residing in England. These are being updated on a weekly basis and include both positive and negative test results. On a monthly basis, information directly linked to primary care data, hospital inpatient data, and death data will be made available along with critical care data for those individuals that have been confirmed as having COVID-19. The UK Biobank for example has now also initiated a coronavirus antibody study where they will invite a representative sample of 20,000 of the total 500,000 participants who express an interest in participation. They will be asked to self-collect 0.5 mls of blood from finger prick for antibody testing. This will be repeated monthly for at least 6-months. Children and grandchildren of the participants, who are over the age of 18 years will also invited to provide blood samples for both antibody testing and genetic testing to additionally assess for genetic susceptibility in young adults.The growing COVID-19 related information for a cohort with a rich phenotype and genotype assessment along with regular outcome measure updates will allow researchers to define the relevance of wide-ranging genetic and non-genetic factors to severity and outcomes based on age, lifestyle, co-morbidities, prescribed medications, environmental, and regional factors. The outcome data now and in the future will provide a comprehensive analysis of the mortality rates and associated morbidity in the UK cohort. Particularly where the data are able to help identify risk factors that predispose to poorer outcomes and those that could be protective thus guiding lifestyle and prevention recommendations. This creates a colossal opportunity for detailed analysis of the cohort and the impact of the disease on longer term health and well-being of survivors that will guide future research and public health policies.In those who have already undergone deep imaging phenotyping, follow-up scanning will provide novel insights in understanding the downstream, long-term effects of COVID-19 exposure on biological systems. Analysis of the subset of participants undergoing follow-up imaging could also provide better understanding of pathophysiology using the pre- and post-COVID-19 imaging data.https://www.covid19hg.org). The second-round meta-analyses of the genome-wide association studies of COVID-19 status had been released. This initiative may not only enrich our knowledge of COVID-19 biology but provide the genetic evidence for drug targets and assist in the development of genetically informed risk assessment of COVID-19 susceptibility. The genetic data also allow the conduct of Mendelian randomization studies which permit evaluation of causality in observational settings (The UK Biobank is already one of the largest contributors to an international consortium to investigate the genetic determinants of vulnerability to COVID-19, disease severity and outcomes (settings .There is already a large interest from researchers globally in the UK Biobank study which will lead to healthy competition for research and publication. As large groups of researchers may be working in silos on similar projects there may large efforts with those being quickest getting publications. Due to the need for timely submissions for publication there is a potential risk for less rigor or quality control checks during data cleaning and analysis .The UK Biobank enrolled middle and older aged adults only and Caucasians making up the vast majority of participants, with limited number of other ethnicities . No partImpact of delayed uptake of population screening through swabbing in the UK in those with milder disease along with lack of systematic symptom data may limit the research potentials. There is also a chance that key findings may only be generated once we have passed the worst period of the pandemic.Data sharing that allow combination of large cohorts from around the world including the UK Biobank study and other larger population initiatives will increase the richness of the data and allow better assessment of geographical variations, ethnic differences and similarities to better guide public health policies and ways of managing future pandemics.COVID-19 has had a global impact and will change our health care approaches in the future. The UK Biobank population study can offer great opportunities given the detailed systematic nature of the assessments along with the growing linkage to the current COVID-19 testing and outcome data. The true potentials of the UK Biobank and other large population-based research studies will become evident as the data accumulate over time and may be enhanced further by linking large population-based studies which can allow limitations such as ethnic and geographical differences and guide optimisation of public health policies.https://www.ukbiobank.ac.uk/register-apply/.Publicly available data from the UK Biobank study was analyzed in this study. The datasets are available to researchers through an open application via All authors have made substantial contributions to conception and design, involved in drafting the manuscript or revising it critically for important intellectual content, and given final approval of the version to be published. All authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.SP provides consultancy and has stock options for Circle Cardiovascular Imaging, Inc., Calgary, Alberta, Canada. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Laser-based inspection of trivalent chromium conversion coatings on rough, cold-rolled aluminium substrates is studied from a basic physics perspective by means of angle and wavelength dependent measurements. As a result, we show that the correlation between the scattered laser light and the coating weight of the conversion layer is dominated by the phenomenon of interference. The combined experimental and numerical approach of our study is based on an appropriate layer model which was developed from a set of reference measurements of confocal microscopy, electron microscopy and X-ray photoelectron spectroscopy. The aluminium alloy AA3003 with a trivalent chromium conversion coating serves as an example. Our derived model is capable to reconstruct the reflectance of a laser beam at grazing incidence even for a pronounced surface roughness of  According to the literature, several papers have already been published using SurTec® 650 as passivation agent on different aluminium alloys backing our choice [It is impossible to imagine today’s everyday life without functional coatings modifying and enhancing the surface properties of different materials. Specially tailored for specific applications they serve a broad range of functionalities, for example the improvement of historic urban districts , drag rer choice ,11,12,13r choice . While mr choice ,16, thisn regime . At thisn regime .M [M have been investigated. Our measurand An optical method capable of detecting and distinguishing between different thicknesses of trivalent chromium conversion (TCC) coatings on rough cold-rolled AA3003 aluminium substrates has already been presented in the literature by us showing that our suggested measurand weight M . This fiIn this publication we address the underlying physical origin of the previously found correlation.The samples investigated in our study are briefly presented in this chapter. As mentioned above, the popular general-purpose aluminium alloy AA3003  for determining the topography, especially the surface roughness described by FEI Helios NanoLab 600) and a focused ion beam section to gather information about the coating thickness and uniformity. Third, X-ray photoelectron spectroscopy  to evaluate the chemical composition of the TCC coatings at the air–coating interface.For the purpose of understanding the physical origin of the connection between our measurand M-URM80CC) as goniometer. Thus, we can precisely control the angle of incidence DD405), 532 DD532), 633 L785P090) emitting 785 The experimental setup for the optical measurements is schematically sketched in In the first part of this chapter we present the results of the reference measurements, enabling us to perform an appropriate characterization of the samples. Second, the findings of the optical setup presented in pecimens .The roughness and peak-to-valley distance of all investigated samples are presented in For gathering information about the coating thickness and its uniformity, we used SEM measurements after preparing a small section with a focused ion beam. The left part of ® 650 since other authors have also observed an accumulation of carbon within the conversion layer [To evaluate the chemical composition of the TCC coatings at the air–coating interface we used XPS measurements. We examined the samples at two different positions and present the results after averaging in on layer ,9. The hon layer . The dif CrF3  57.2eV accThis section deals with the dependency of our measurand For having a closer look at the influence of the used wavelength M. Furthermore, the necessity of a carefully chosen wavelength and angle of incidence is shown. In the following section we answer the question regarding the physical origin of the previous described correlation.The inspection of TCC coatings on cold-rolled aluminium substrates by means of our previous described setup provides a strong relationship between our measurand First, we focus on the mathematical description of the light scattering with the uncoated specimen Ref. The LSCM measurements from Beckmann and Spizzichino derived that the averaged, squared electric field k denotes s-polarized or p-polarized light and Restricting ourselves to grazing incidence  the following requirements have to be fulfilled: First, a metallic substrate is required to induce a phase difference between s- and p-polarized light for investigating coatings thinner than 70 The understanding of the strong correlation of our measurand We were able to use the setup for other substrates with even further increased roughness due to electronic discharge texturing and thinner conversion coatings applied.


Geochemical processes change the microstructure of rocks and thereby affect their physical behaviour at the macro scale. A micro-computer tomography (micro-CT) scan of a typical reservoir sandstone is used to numerically examine the impact of three spatial alteration patterns on pore morphology, permeability and elastic moduli by correlating precipitation with the local flow velocity magnitude. The results demonstrate that the location of mineral growth strongly affects the permeability decrease with variations by up to four orders in magnitude. Precipitation in regions of high flow velocities is characterised by a predominant clogging of pore throats and a drastic permeability reduction, which can be roughly described by the power law relation with an exponent of 20. A continuous alteration of the pore structure by uniform mineral growth reduces the permeability comparable to the power law with an exponent of four or the Kozeny–Carman relation. Preferential precipitation in regions of low flow velocities predominantly affects smaller throats and pores with a minor impact on the flow regime, where the permeability decrease is considerably below that calculated by the power law with an exponent of two. Despite their complete distinctive impact on hydraulics, the spatial precipitation patterns only slightly affect the increase in elastic rock properties with differences by up to 6.3% between the investigated scenarios. Hence, an adequate characterisation of the spatial precipitation pattern is crucial to quantify changes in hydraulic rock properties, whereas the present study shows that its impact on elastic rock parameters is limited. The calculated relations between porosity and permeability, as well as elastic moduli can be applied for upscaling micro-scale findings to reservoir-scale models to improve their predictive capabilities, what is of paramount importance for a sustainable utilisation of the geological subsurface. The prediction of the resulting changes in effective hydraulic and mechanical rock properties is of paramount importance for numerous natural geochemical systems and commercial applications such as geothermal energy production ,2, hydro storage ,13. Rega storage ,15 may bFor an adequate prediction of physical rock properties, it is necessary to characterise the initial microstructure including the morphology and connectivity of pores. In general, precipitation reduces the porosity, but the effect on transport properties may be either negligible or significant depending on the specific location within the pore network . The spaHowever, of actual interest within the context of subsurface utilisation is the impact of pore-scale precipitation on hydraulic and mechanical rock properties. Numerous empirical and analytical relationships describe the dependency between porosity and permeability ,29,30 asIn the present study, the effect of precipitation on hydraulic and mechanical rock properties is numerically examined for a typical granular reservoir rock, namely the Bentheim sandstone. Changes in pore morphology, permeability as well as bulk and shear moduli are quantified based on a highly resolved micro-scale representation of the rock. The permeability is determined from the flow field by solving the steady-state Stokes equation , whereas3 voxels is extracted from the entire micro-CT scan  in the direction of flow can be calculated by the volume average of the velocity field k=vmμThe extent to which changes in porosity affect permeability strongly depends on the location of mineral precipitation, since it changes the pore morphology and thus the flow parameters. It is important to note that the aim of the present study is to examine the general bandwidth of hydraulic and mechanical property changes due to dissimilar pore-scale precipitation patterns, and not to simulate a specific chemical process of mineral nucleation and growth. Hence, the alteration of the pore space is implemented by a voxel-based algorithm converting void to mineral based on the local flow velocity field without the explicit consideration of fluid-rock interactions. Godinho et al.  observedThe elastic properties of the digital rock sample are determined by a parallel version of the static finite element method of Garboczi and Day . This wev represents the P- or S-wave velocity, P is the confining pressure and a, k, b, d are fitting coefficients. The mineral moduli of the quartz phase are calibrated using this formulation  at low flow velocities. A smaller amount of 19% of the initial pore throats is clogged completely. Moreover, this scenario exhibits the least reduction in pore size, where the average diameter reduces from 92 μm to 82 μm, only. Mineral growth affects all pore sizes, but occurs more frequently in smaller pores (<90 μm) compared to a uniform alteration, whereby 11% of the initial pores are completely clogged. Precipitation in the pore space does not substantially affect the connectivity of the entire network, since the mean value is only slightly reduced to 4.2 . ParticuThe most remarkable differences between the three considered scenarios occur in the number and size distributions of the pore throats, with the highest reduction in the HFV case and minor changes considering precipitation in LFV regions. Changes in pore throats directly impact the connectivity of the pore network, whereby an equivalent trend is observed. The diameters of larger pores are comparably reduced for all three precipitation patterns, whereas a contrasting effect occurs for pores smaller than 90 μm. The sphericity significantly differs between all three precipitation mechanisms. It decreases in the HFV case due to the irregular shape and rougher pore structure, while it increases in the LFV scenario in which the surface area is smoothed.The initial flow regime within the pore space of the Bentheim sandstone is highly variable with fluid velocities varying over several orders of magnitudes. The histogram in The simulated pore alteration mechanisms with their particular morphological changes strongly impact the fluid flow paths and velocities. In case of preferential precipitation in HFV regions, a majority of the initial flow paths are cut-off a due to The calculated permeability of the unaffected microstructure is in good agreement with the published data for the Bentheim sandstone b. In casThe calculated elastic rock properties of the initial microstructure based on the calibrated bulk and shear moduli for the grain phase are in good agreement with published laboratory data for the Bentheim sandstone ,72,78,79Variations in stress concentrations between the spatial precipitation patterns are associated with the grain contacts. In general, stress concentrates at the grain-to-grain interfaces, as it is clearly visible for the initial microstructure b. DespitThe three considered scenarios assume a preferential precipitation depending on the magnitude of fluid flow velocity and can be associated with general contrasting chemical processes. A predominant mineral growth near pore throats, where fluid flow velocities are relatively high (HFV), represents a transport-controlled process. Thereby, advection dominates and the reaction is limited by the availability of reactants transported to the fluid-mineral interface , which ik) and initial permeability  and transport-controlled precipitation (HFV case) can be determined for a representative elementary volume of a granular rock. Moreover, the calculated porosity-permeability relations, as well as the increase in mechanical properties are transferable to reservoir-scale models and can describe the physical rock properties as a consequence of mineral precipitation, e.g., in the context of reservoir engineering to determine the amount of precipitate leading to a considerable reduction in productivity or injectivity. For a specific application, it would be reasonable to determine whether the particular geochemical process is mainly reaction- or transport-controlled. Thereby, the range of uncertainty in the porosity-permeability relation can be substantially reduced.The presented approach numerically examines the impact of mineral precipitation on hydraulic and mechanical properties for a granular reservoir rock. A micro-CT scan of the Bentheim sandstone is used as a highly resolved digital rock sample. The permeability is determined from the flow field by solving the steady-state Stokes equation, whereas effective rock stiffness is calculated by a static finite element method. To investigate the impact of the location of precipitation on pore morphology, permeability and elastic moduli, the initial microstructure is altered by preferential precipitation at high flow velocity magnitudes, low flow velocity magnitudes and a uniform mineral growth around the grains.The results of this study demonstrate that the location of precipitation strongly affects the permeability with variations by up to four orders in magnitude, whereas the impact on elastic rock properties is limited with differences of 6.3% in maximum. The number and size of pore throats, and hence the connectivity of the pore network are mainly responsible for the distinctive permeability reduction resulting from the investigated pore space alterations. Preferential precipitation in regions of high velocity magnitudes can be associated with a transport-controlled reaction regime. It is characterised by a predominant clogging of pore throats, resulting in a drastic reduction in overall connectivity of the pore network. Hence, the permeability strongly decreases, whereby the porosity-permeability relation can be roughly described by the power law with an exponent of 20. A uniform mineral growth around the grains is associated with reaction-controlled precipitation, whereby the size of all pores is equally reduced. The reduction in permeability is less pronounced and can be approximated by the power law with an exponent of four or the Kozeny–Carman relation. Preferential mineral growth in regions of low flow velocities affects predominantly smaller throats and pores with a minor impact on the flow regime. Hence, the reduction in permeability is considerably below the power law with an exponent of two, and it is concluded that this scenario does not represent a natural process of precipitation within the pore space.The stiffening trend in bulk and shear moduli amounts circa 0.63 GPa and 0.47 GPa per percent porosity decrease, respectively. Porosity is clearly the controlling parameter for the increase in effective bulk and shear moduli. Moreover, small variations between the spatial alteration patterns are associated with the grain contacts, whereby both flow velocity-dependent precipitation patterns enhance the grain contacts, resulting in a slightly stiffer behaviour than the uniformly altered sample. Hence, a detailed consideration of the spatial alteration pattern is not required and the increase in elastic moduli can be approximated by an easily-implementable uniform grain coating, whereas an adequate characterisation of pore alteration patterns is crucial to quantify the reduction in hydraulic rock parameters.The presented approach offers a simplified estimation of spatial pore space alteration for surface reaction-limited and transport-controlled geochemical reaction regimes without the requirement of implementing complex reactive transport simulations. Digital rock physics in view of a virtual laboratory can be used to quantify changes in effective rock properties for different rock microstructures or chemical reaction regimes. Hence, the calculated porosity-permeability relations as well as changes in mechanical properties can be applied in reservoir-scale numerical simulation models to improve their predictive capabilities, which is of paramount importance for an improvement of processes understanding and a sustainable utilisation of the geological subsurface.


This study aims at evaluating the aetiology and outcome of acute hemiplegia in children admitted into the University of Calabar Teaching Hospital (UCTH), Nigeria.a 5-year retrospective review of all children admitted to the Neurology Unit of the Department of Paediatrics of UCTH with a diagnosis of acute hemiplegia. The demographic characteristics of the children and the clinical features were noted. Investigations including neuroimaging of the brain and haemoglobin genotype were documented. The outcomes of the patients were recorded as either dead, recovered with deficit or loss to follow up. Data obtained was analysed using the SPSS version 24. Simple tables were used to display the results in number and percentages.twenty-five children with diagnosis of hemiplegia were admitted. Associated clinical features were prolonged seizures (68%), speech defect (32%), cranial nerve deficit (36%) and loss of consciousness (12%). Viral encephalitis was the common aetiology in 11(44%) of the patients, followed by meningitis and sickle cell anaemia in 6(24%) patients each. Four(16%) of the patients recovered completely within the follow up period of three month, 19(76%) had varying degrees of weakness; 2(8%) died. Twelve (48%) were lost to follow-up.central nervous system infections and sickle cell disease as dominant aetiological factors of acute hemiplegia in Nigerian children. This calls for effective infection control and genetic counselling. This excludes children with hemiplegia related to perinatal insult such as prematurity, birth asphyxia, birth trauma and perinatal infection. Hemiplegia is less common in children compared to adults and the pathological condition and underlying aetiologies thereof are much more varied ,2. Cereb disease ,6. With  disease . This stThe study is a 5-year retrospective review on the records of all children admitted to the Children Emergency and the Neurology Unit of the Department of Paediatrics of the University of Calabar Teaching Hospital UCTH, Calabar, Nigeria, with a diagnosis of acute hemiplegia. These includes all children with hemiplegia of acute onset (weakness on one side of the body) that occurred postnatally and excludes hemiplegia arising from perinatal events such as prematurity, severe birth asphyxia, birth trauma and CNS infections. The demographic characteristics of the children abstracted from the record were age, gender, ethnic group, the social class of the children. The premorbid conditions of the children, particularly those with sickle cell anaemia (HbSS), were noted. Children with cerebral palsy and chronic hemiplegia were excluded from the study. As a hospital policy, all children presenting with neurological symptoms including hemiplegia are admitted into the neurology wing of the paediatric ward. The unit is manned by three consultant neurologists and residents. There are no facilities for viral studies/serology. Patients were presumed to have viral encephalitis if they were admitted with high fever, convulsions, altered sensorium plus other features of acute cerebral symptomatology but their spinal fluid was normal and malaria smear was negative. The clinical features at presentation were noted; and laboratory investigations undertaken during the acute events including blood chemistry, full blood count, haemoglobin genotype, spinal fluid analysis, malaria smear and brain neuroimaging were recorded. The outcomes of the patients were recorded as either dead, recovered with deficit or lost to follow up. All clinical information obtained was entered into a Microsoft Excel spread sheet and same analysed using the SPSS version 24. Simple tables were used to display the results in number and percentages.Within the 5-year period of study, 25 children with a diagnosis of acute hemiplegia were admitted into the neurology unit. These were made of 13 males and 12 females. The age/gender distributions of the children are shown in From this study, CNS infections comprising of viral encephalitis and meningitis appear to be the dominant underlying causes of acute hemiplegia in Nigerian children. Other similar surveys -6,8-10 hIncreased red cell adhesion, oxidative injury of the vessel wall, inflammation, abnormal vasomotor tone regulation and increased activity of the coagulation system may all contribute to cerebral vascular obstruction in sicklers . Three (Infections of the CNS and sickle cell anaemia appear to be the predominant underlying causes of acute hemiplegia of childhood in Nigeria. It is therefore necessary that every child with acute hemiplegia should be evaluated for CNS infections and sickle cell disease. Infectious disease control and genetic counselling regarding sickle cell hemoglobinopathy, can be useful regarding the prevention of this handicapping condition in children.Acute hemiplegia occur in children;The aetiology of acute hemiplegia varies from that of adults;Heamoglobinopathies are common causes of acute hemiplegia in children.Central nervous system infections should be considered as an important differential in all cases acute hemiplegia;HIV infection should considered as an important cause of acute hemiplegia in children and routine screening should be carried out in this condition;Sickle cell heamoglobinothies still remains an impotant cause in the tropics.


C) into infectious aggregates (PrPSc). The detailed molecular basis of the misfolding and aggregation of PrPC remains incompletely understood. It is believed that the transient misfolding of PrPC into partially structured intermediates precedes the formation of insoluble protein aggregates and is a critical component of the prion misfolding pathway. A number of environmental factors have been shown to induce the destabilization of PrPC and promote its initial misfolding. Recently, oxidative stress and reactive oxygen species (ROS) have emerged as one possible mechanism by which the destabilization of PrPC can be induced under physiological conditions. Methionine residues are uniquely vulnerable to oxidation by ROS and the formation of methionine sulfoxides leads to the misfolding and subsequent aggregation of PrPC. Here, we provide a review of the evidence for the oxidation of methionine residues in PrPC and its potential role in the formation of pathogenic prion aggregates.Prion diseases are characterized by the self-templated misfolding of the cellular prion protein (PrP C) into insoluble protein aggregates (PrPSc) in the central nervous system .–91.89–91ic cycle  93]. Th. Th+ perC, produced recombinantly or purified form mouse brains, binds copper ions in vitro and has superoxide dismutase-like activity that inhibits the accumulation of ROS [The high content of surface exposed methionines within the structure of PrP has been suggested to play a role in the endogenous antioxidant defense of neurons that express PrP. Similar to most neurodegenerative disorders, prion diseases are associated with a significant increase in ROS and oxidative stress ,97. Seven of ROS ,100. Subn of ROS . These rn of ROS . These cC involves the metal-catalyzed modification of amino acids near the copper binding sites. Residues within the unstructured N-terminal domain, M109/112 and His96/His111, were reported as the residues most vulnerable to metal-catalyzed modifications [C act as sacrificial oxidants to limit the diffusion and reactivity of copper generated ROS. As described above, unlike histidines, the sacrificial oxidation of methionines can be reversed by Msrs, restoring the antioxidant activity of PrPC.More recent reports have suggested that the antioxidant mechanism of copper-bound PrPications . The autC, the authors of this study suggested that PrPC may play an indirect role in the regulation of SOD-1 activity. Later reports demonstrated that the regulation of SOD activity by PrPC is dependent on the interaction between the octapeptide repeat (OR) region and the N-terminal half of the hydrophobic region (HR) of PrP and stress inducible protein 1 (STI1) [C may promote oxidative stress tolerance of neurons through two independent mechanisms. First, PrPC may directly enhance oxidative stress tolerance by utilizing methionine residues as sacrificial oxidants that can be recycled by the Msr pathway. Second, PrPC may play an indirect role in oxidative stress tolerance by regulating SOD activity. Future studies aimed at quantifying the relative contributions of these two functions may shed light on the role of oxidative stress tolerance in the progression of prion diseases.Interestingly, neurons cultured from PrP-deficient mice have SOD-1 activities that are unresponsive to oxidative stress, suggesting a role for PrP in the adaption of SOD-1 activity to oxidative stress . Due to 1 (STI1) ,105. TheIt should be noted that a study of transgenic mice lacking the MsrA gene suggested that MsrA does not play a role in prion pathogenesis . This stC. A number of in vitro studies have demonstrated that methionines in PrPC are vulnerable to oxidation. Methionine oxidation alters the structure of PrPC and generally decreases its stability. The consensus mechanism that has emerged from these studies is that the oxidative misfolding of PrPC likely begins by the oxidation of surface methionines and proceeds through subsequent oxidation of buried or partially buried methionines. The oxidation of buried methionines is required for the complete destabilization of PrPC and conversion to beta-rich aggregated structures , suggesting that methionine oxidation may play a similar role in dictating the formation of prion strains [in vivo methionine sulfoxide levels within a range of prion strains and host species using more accurate analytical methodologies may help clarify the role of methionine oxidation in the pathology of prion diseases. Additionally, a greater understanding of the role of the Msr system in the progression of sporadic and inherited prion diseases will shed light on the role of PrPC as an endogenous antioxidant. Together, these studies could significantly advance our understanding of the pathogenic mechanism of prion diseases and facilitate the development of new therapeutic strategies.Recent advances have provided a detailed understanding of the effects of methionine oxidation on the structure and stability of PrPructures . However strains . Future


Light microscopy (LM) is commonly used in the study of biological materials to determine the morphology of cells and tissues. The potential of this technique for studying the structure of food products is also recognized but less known. Especially rare are information regarding LM studies of the supramolecular structure of starch. The aim of the work was to fill this gap by providing data on the possibilities for application of LM in starch studies. It was shown that in spite of an enormous progress in the development of microscopic techniques, including both increase of resolution and improvement of image analysis methods, light microscopy still has a huge potential for starch studies. The advantage of LM over other microscopic techniques is the possibility of differentiating between amylose and amylopectin by iodine staining. That makes LM especially useful in the analysis of the process of gelatinization of starch, the extent of molecular dispersion of its macromolecules, and the changes in its structure caused by modification. Moreover, it can be particularly useful for studying the changes in the supramolecular structure of starch in a food product matrix, providing more information than scanning electron microscopy (SEM)–the most common technique used for these purposes. The history of the use of microscopy in starch research dates back to the early days of microscopy in XVII century and is closely related to the findings of Antonie van Leeuwenhoek who confirmed the presence of starch in various parts of plants . MoreoveThe topography of granules i.e., presence of pores, channels or non-starch compounds, may distinctly modify the physicochemical properties of starch with emphasis on its susceptibility to chemical or physical treatment. Atomic force microscopy (AFM) has been successfully used to probe surface structures, determine the surface properties of native and/or modified starches  and the interactions of polymers at the nano-structural level ,11,12. AThe combination of various microscopic and/or spectroscopic techniques allows scientists to analyse not only the structural alterations but also the changes in the chemical profile of the processed granules ,18. On tThe aim of this work was to fill this gap by providing data that regards the possibilities for application of LM in starch studies. The gelatinization process of the most popular commercial starches that differ in amylose content and in pasting viscosity profile was investigated. This made it possible to show that thickening capability is related to the extent of molecular dispersion of starch. Moreover, microstructure of the most important modified potato starches was studied . It was shown that the incorporation of hydrophilic and hydrophobic moieties into starch macromolecules affected not only the viscosity but also significantly changed the ability to complex iodine within amylose and amylopectin helixes. The application of light microscopy to the studies of cross-linked starch allowed to observe the effect of acids or the sterilisation process on the molecular dispersion of starch and the resulting applicability of different modified starches as texture forming agents for different food products.Commercial native potato starch  was the initially studied material. Commercial pregelatinised drum dried potato starch , oxidised potato starches of different degree of substitution (DS)  and native starches of other botanical origin i.e., tapioca super high grade (Thailand), wheat (Roquette), corn (Cargill) and waxy corn (Cargill) were also used in this study.All modification processes were performed using potato starch as a raw material. Starch extrusion was performed in an industrial scale twin screw extruder (custom made) operating at temperature of 135 °C and 80 rpm. Initial moisture content of starch subjected to modification was 13%. The extrudate was grinded and sieved through a 60 mesh.Acetylated starches were prepared in water suspension with acetic anhydride according ≥98%  to the procedure described in . CrossliPasting characteristics were analysed with a Brabender viscograph under the following conditions: measuring cartridge 0.07 Nm; heating/cooling rate 1.5 °C/min; thermostating 20 min. pH value of starch suspensions subjected to viscographic analyses were adjusted with citric acid. To record light microscopy images, native and modified starches (0.8 g) were suspended in water (10 mL), and depending on the preparation, the starch slurry was incubated or heated at an appropriate temperature for 15 min with vigorous stirring. The temperature conditions, at which the slurry was treated, were determined based on the pasting characteristics of each individual preparation analysed with Brabender viscograph. The temperatures corresponding to the changes in the Brabender profile of the analysed sample, were used for the specimen preparation, and they were given in the captions of the figures presented in the work. A drop of the heated sample was transferred onto glass slides, smeared, and, following cooling, stained with Lugol’s solution (standard procedure). The preparations were examined with an OLYMPUS BX60  microscope.Degree of substitution of food grade modified starches were determined according to JECFA recommendations . For catStarch in its native granular form has very limited applicability, as it is insoluble in cold water. Therefore, the process of its dissolution (gelatinisation or pasting) is a subject of keen interest of technologists. Standard methods for the study of the pasting process involve using viscographs, such as Brabender viscograph or Rapid Visco Analyser. They provide useful information regarding changes in viscosity of starch dispersion in water during heating and cooling. Quantitatively, the process of gelatinisation is studied with differential scanning calorimetry. This technique provides information on the temperature-dependent enthalpy changes that accompany the decay of the crystalline phase in starch granules . HoweverAt room temperature potato starch granules remained unchanged and were visualised in the micrographs as black spots A. This cLight microscopy makes it also possible to visualise the differences between starches of various botanical origin. As presented in Many methods of starch modification have been developed in order to enhance the positive attributes and eliminate the shortcomings of the native starches . The mosSignificant differences were visible between drum dried and extruded starches. Both of these starches reveal lower viscosity when compared to their not processed counterpart. However, this difference is more pronounced in extruded starch . LM pictThe reactivity of hydroxyl groups present in the structure of starch macromolecules creates the possibility for various chemical reactions which results in a vast range of modified starches. Despite the enormous variety of modified starches offered on the market, the applied chemical reactions can be classified to three types: oxidation, esterification, and etherification. The use of multi-functional reagents  enables cross-linking of starch macromolecules in the course of esterification or etherification. This creates almost limitless possibilities of precise tuning of the properties of modified starches to specific applications .Oxidation of starch can be performed with different agents, such as hydrogen peroxide, ozone or sodium periodate. Nonetheless, the process that employs sodium hypochlorite is of the greatest practical importance. Hypochlorite modified starches were initially used primarily as sizing agents . NeverthChanges in the starch pasting process and in the starch-water interactions that were related to the oxidation of starch were also reflected in the LM images . At the However, the most important observation coming from the LM studies of oxidised starch is probably the one concerning colour upon iodine staining. The colour was significantly altered in comparison to micrographs of native starch. This observation is important because of the popularity of iodine colorimetry for determination of amylose content . SubstitAcetylation of starch, like oxidation, has been known for over 150 years and still is of industrial importance. This reaction is applied either to obtain exclusively acetylated starches or dually modified acetylated crosslinked derivatives. Acetylation performed in anhydrous media makes it possible to achieve a very high degree of substitution, up to 2.9. For this reason, starches modified by this method have significantly changed morphology, decreased crystallinity, and are soluble in non-polar solvents . For appEven by the presence of less than one acetyl group per hundred anhydroglucose units, no more blue colour that corresponds to amylose-iodine complex could be observed A. This oCrosslinked starches are readily used in food production. A very slight change in the structure of starch macromolecules causes huge changes in the properties of this biopolymer. The degrees of substitution of food grade crosslinked starches are about an order of magnitude lower than those of monostarch derivatives . CrossliLow cross-linked distarch phosphate, the most popular variant of E1412 in food technology, revealed higher viscosity than native potato starch in pH = 5.5. Microscopically, it was manifested by the formation of a paste at the temperature of 90 °C A that waAcetylated distarch phosphate samples revealed gelatinisation patterns similar to their non-acetylated counterparts . When coStarch modified by the etherification reaction are primarily hydroxypropylstarch used both in food production and other industries as well as cationic starches designed for paper sizing. Hydroxypropylation results in a significant decrease in pasting temperature, time to attain peak viscosity accompanied by increased solubility, and paste clarity. Moreover, hydroxypropylated starches reveal excellent freeze-thaw stability as well as reduced retrogradation tendency which is important in food applications. SEM studies proved that hydroxypropylation results in deep changes in the morphology of starch granules, including the main alteration – formation of deep grooves in the central core region. The extent of these changes depends on the amount of the hydroxypropyl groups incorporated into starch macromolecules ,37,38. TTo obtain products with higher degrees of substitution, dry or semi dry reaction conditions are required. Starches subjected to such conditions not only change their morphology but also lose their crystal structure ,39. The Despite the great progress in microscopy, visual light microscopy remains a potentially useful technique for studying the structure and functionality of starch. While advanced microscopic techniques, such as AFM, CLSM or SEM, provide more detailed information regarding the morphology of the starch granule, LM can be successfully used to demonstrate the structural changes of starch in dispersed systems. With the use of LM, amylose can be easily distinguished from amylopectin by iodine staining. Moreover, the extent of molecular dispersion of starch in pastes as well as the changes in the polymer-solvent interaction caused by the substitution of hydroxyl groups with polar or non-polar moieties can also be successfully studied under LM. These features make the technique particularly useful for investigating the changes in the supramolecular structure of starch in the matrix of food products as they allow to obtain essential and detailed information.


The osteopathic community has long hypothesized that the autonomic nervous system (ANS) represents one of the putative substrates through which osteopathic manipulative treatment (OMT) can improve body functions that have been altered by musculoskeletal alterations. Heart rate variability (HRV) is an important physiological measure of cardiac ANS activity. Emerging evidence suggests that OMT is associated with HRV changes that (i) are indicative of a larger cardiac vagal modulation, (ii) are independent from the part of the body needing treatment, (iii) occur even in the absence of musculoskeletal alterations. Yet, many questions remain unanswered, the duration of these effects and the specificity of HRV responses to different OMT techniques being perhaps the most critical. Therefore, this paper discusses prospects for future applications of HRV for the study of the influence of OMT on ANS function. Moreover, based on existing studies and preliminary data on the effects of OMT on HRV in specific pathological (hypertension) and physiological (stress exposure and recovery from sport competition) conditions that are commonly associated with increased sympathetic and/or decreased vagal activity, we propose that HRV analysis could be exploited to evaluate the effectiveness of OMT as a preventive or complementary strategy in clinical and non-clinical conditions characterized by ANS imbalance. Osteopathic manipulative treatment (OMT), a non-invasive form of manual therapy, has evolved as a therapeutic approach aimed at correcting alterations in musculoskeletal structures that are having direct or indirect negative effects on the perfusion of body tissues and inherent physiological function. This perspective article is centered around the belief, within the osteopathic community, that the autonomic nervous system (ANS) represents one of the putative substrates of the action of OMT and its favorable effects on body functions . SomaticAutonomic regulation of most visceral organs reflects the balance between sympathetic and parasympathetic  modulation. This is particularly apparent in the neural control of the heart, where the balance between sympathetic excitation and vagal inhibition of sinoatrial node activity contributes to beat-to-beat heart rate fluctuations, also known as HRV. Traditionally, several HRV indices and methods have been used to quantify cardiac sympathetic and vagal influences . HoweverThe use of HRV as a proxy for ANS function has become a popular approach in several clinical and investigational domains e.g., . In factn = 57) of asymptomatic adults . Interestingly, an increase in measures of vagally mediated HRV obtained via plethysmography was observed during both the 15-min OMT treatment and the following 5 min when no hand contact was provided  and physiological (stress exposure and recovery from sport competition) conditions that are generally associated with increased sympathetic and/or decreased vagal activity.Hypertension is commonly associated with increased sympathetic and decreased vagal activity , and redIt is widely known that stressors tip the ANS balance toward a larger sympathetic prevalence and activate the hypothalamic-pituitary-adrenal axis . In a between-subject study conducted by our group, a single-session of OMT using craniosacral techniques was performed immediately after an acute mental stressor on a small sample of healthy young men (20–30 years old) . We founConditions of ANS imbalance characterized by decreased vagally mediated HRV have also been described in athletes in the aftermath of a sport competition or in the presence of overtraining syndrome . ConsistThe specific pathophysiological mechanisms underlying the influence of OMT on ANS function, and specifically HRV, are currently unknown. However, we may put forward several hypotheses. For example, musculoskeletal alterations may increase sympathetic activity via proinflammatory mediators , and/or The study of the relationship between OMT and the ANS is very much in its early days. However, the analysis of HRV in experimental investigations on this link has started to provide preliminary insights into the ability of OMT to tip the ANS balance toward a relatively larger cardiac vagal modulation in healthy subjects. Many questions remain unanswered, the duration of this effect and the specificity of HRV responses to different OMT techniques being perhaps the most critical. We therefore encourage future randomized controlled trials adopting different treatment protocols and longer HRV assessment to address these questions in healthy populations and individuals with diagnosed somatic dysfunctions. Specifically, we would advise researchers to adopt the three Rs design  mentioned in The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation, to any qualified researcher.The studies involving human participants were reviewed and approved by the Institutional review board of the Collegio Italiano di Osteopatia in Parma. The patients/participants provided their written informed consent to participate in this study.LC and AS were involved in the conception and design of this article. LC, LL, and MF conducted the pilot study. LC wrote the first draft. LL, MF, and AS revised the manuscript critically for important intellectual content. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer ET declared a past co-authorship with several of the authors LC, AS to the handling Editor


In this paper, a novel dynamic Vision-Based Measurement method is proposed to measure contact force independent of the object sizes. A neuromorphic camera (Dynamic Vision Sensor) is utilizused to observe intensity changes within the silicone membrane where the object is in contact. Three deep Long Short-Term Memory neural networks combined with convolutional layers are developed and implemented to estimate the contact force from intensity changes over time. Thirty-five experiments are conducted using three objects with different sizes to validate the proposed approach. We demonstrate that the networks with memory gates are robust against variable contact sizes as the networks learn object sizes in the early stage of a grasp. Moreover, spatial and temporal features enable the sensor to estimate the contact force every 10 ms accurately. The results are promising with Mean Squared Error of less than 0.1 N for grasping and holding contact force using leave-one-out cross-validation method. Tactile sensors are developed to acquire physical properties of the contact area between the sensor and environment. Similar to human skin receptors, tactile sensors are capable of measuringcan measure physical properties such as position, force, torque and temperature in the contact point. However, industrial applications require different specifications for the sensor in terms of resolution, latency, and accuracy based on the functionality of the system. Thus, researchers utilizuse a variety of measurements methods to tackle sensing challenges and overcome limitations of the sensors for diverse real-world applications .The rise of robotic systems in automation increases the popularity of tactile sensors for the safe human robot interaction , soft roVision-based sensors are a subcategory of optical sensors that utilizuse cameras and image processing techniques for measurement and sensing purposes. Advancement in camera technology, machine vision techniques, and processing power, increase the number of Vision-Based Measurement (VBM) systems significantly . The funA new biologically inspired type of cameras, neuromorphic vision sensors, use a differential approach to acquire information from the scene. Neuromorphic (Event-based) vision sensors capture intensity changes in a binary format at every pixel (events), timestamped using microsecond resolution, rather than absolute intensity values of all pixels at fixed frame-rateframerate. The main advantages of the neuromorphic sensors like like the Dynamic Vision Sensor (DVS) against the conventional cameras are high temporal resolution, high dynamic range and low power consumption .In , we propThe main contribution of this paper is to propose a novel technique to measure force for objects with different sizes using neuromorphic vision sensors. The proposed sensor observes the silicone membrane deformation in the contact area to estimate the force. Three LSTM-based deep learning models are developed, and the results are compared for dynamic force measurements. The main advantage of our dynamic method is that the history of changes in the contact area are taken into account for the force measurements at each timestamp. Therefore, the sensor is capable of measuring force continuously from start of grasp until release of the object by considering the history of contact at each pixel. This approach enables the sensor to estimate the contact force accurately even for the holding phase whereas a slight vibration occurs. Moreover, the sensor latency is reduced to 10 ms (one frame) due to the networks architectures which is 52% less compared to our previous work using Time Delayed Neural Networks (TDNN) with 21 ms delay . The maiThis paper is organized as follows: Related work is reviewed in The main principle of vision-based tactile sensors is to characterize deformation of flexible fingertip in order to acquire measurements and detect slippage in the contact point. Three main techniques are developed to acquire information from the contact area: (i) Light- conductive plate; (ii) Reflective membrane; (iii) Marker-based membrane. Light-conductive tactile sensors emit light to the contact area and the camera observers light intensity changes to acquire contact position and measure force . ReflectMarker-based tactile sensors consider markers or pins inside the elastic fingertip and correlate displacement of the markers to the contact area properties. One of the earliest works , presentRecent vision-based sensors attempt to utilizuse advanced computer vision and machine learning techniques to increase the sensor capabilities. For instance, a multi-task vision based tactile sensor (GelSight) is developed to estimate the contact force and detect object slippage  using CoOn the other hand, dynamic (recurrent) networks benefit from time-dimension features in measurements. In , a dynamIn ,23 a FinBesides different algorithms and techniques in the vision-based tactile sensing, other factors such as fingertip material and pins design affect the sensing performance significantly. Ward-Cherrier et al.  designedNeuromorphic vision-based tactile sensing is relatively a new research field which aims to utilizuse event-based cameras to acquire physical properties in the contact area. In the earliest work , we propRemarkable progress has been made in vision-based tactile sensors in terms of accuracy and resolution. Nevertheless, most of the previous work considers conventional cameras and static approaches to provide the contact force measurements. CNN-based methods like  have shoThe main limitations of vision-based tactile sensors are low sampling rate and high power consumption compared to other types of tactile sensors. UtilizationUse of event-based cameras for tactile sensing applications provides a much higher sampling rate as well as significant reduction of power consumption. Neuromorphic vision sensors have become significantly popular recently and introduce a paradigm in computer vision applications for instrumentation and measurements ,30. The k is a counter for events and The output of the DVS is a stream of events, each characterized by position, timestamp and polarity T). The time window is selected based on the DVS threshold, application speed and noise. Positive and negative polarities (p) represent a decrease or increase of the contact forceforce, respectively. Therefore, the accumulation of events are performed separately over two channels. Inspired by [k indicates the event index.To process events as a group, events are accumulated within a time window  were introduced to control memory states . We propLSTM networks have made a significant breakthrough in time-series applications such as speech recognition and action recognition. A typical LSTM unit includes input gate, forget gate and output gate which allows the network to forget unnecessary dependencies to prevent vanishing gradients. Suppose that W and U respectively. The initial value of c and h are defined as zero for the first step. The output information is denoted as o and the sigmoid function presented as For every timestamp, input or update gates i, the forget gate f, the memory cell c or the output gate o while biases for each gate are presented by b. Often, LSTM gate’s activation functions are considered to be either sigmoid or hyperbolic tangent function. All the gates including forget Equation  networks are relatively new modified version of LSTMs that can capture spatial-temporal dependencies. ConvLSTM is proposed in , to foreIn opposed to LSTM layers, ConvLSTM layers maintain both spatial and temporal information of each frame. Due to the non-linearity of silicone material, spatial and temporal features need to be considered for estimation of the contact force during different phases.Convolutional Neural Networks (CNNs) are designed to extract both spatial and temporal features in the image by applying convolution operations of filters in a certain window size. CNN networks have achieved significant success in different applications such as AlexNet  for imagThe main difference between CNNLSTM and ConvLSTM architectures is the order of performing convolution operations on the constructed frames. In CNNLSTM, convolution operation applies on the frames to extract features into a 1D vector which is followed by LSTM units to model extracted features temporally over time. On the other side, ConvLSTM operates convolution within the LSTM gates which maintains the two dimensiondimensions of the input to capture both spatial and temporal information of the constructed frames.This section presents detailed information of the experimental setup, the pre-processing stage and the networks implementation.The experimental setup includes an ATI F/T sensor (Nano17), a DVS sensor, and a Transparent 3D printed plane (static plane) for the Baxter robot which is covered by a silicone layer as shown in For each object size, the gripper and the force sensor are calibrated first and the same process of closing and opening the grippers are followed. Although the experiments are performed with the same configuration, the contact force values and experiments duration are slightly varied due to the silicone elasticity, controllers delay, and measurements uncertainty. As the sensor estimates the contact force continuously, each experiment is divided into the grasping, holding and releasing phases and the sensor performance for each phase is investigated b. To evaIn each experiment, the contact force starts from zero and reaches the maximum of 3.12 N during the holding phase. The releasing phase is highly non-uniform across experiments due to the elasticity of the silicone membrane.The framing process accumulates events in two different channels, as described in The proposed networks are tuned based on trial and error considering various hyper-parameters including number of hidden layers, filters and dropout rate. The networks are designed in Keras framework  and traiThe number of layers and network hyper-parameters are chosen experimentally. The frames represent events over a short period of time which reduce the number of features in each frame. On the other hand, each event in the frame is related to the contact force directly. Therefore, convolutional layers are designed with three filters in size of 3 × 3 and zero padding in each layer. Furthermore, drop out layers are used in the first three layers with rate of 0.4 to prevent over-fitting on the training set.The data is split into three sets of training (31), validation (3), and test (1) sets. Then, leave-one-out technique is implemented to repeat the training and testing of the network 35 times. Early stopping technique is used to stop the training for each fold after 20 iterations without improvement of accuracy on the validation set. To select the validation set, a random experiment is picked up from each size to ensure all object sizes are included. For the final results, error of each network is averaged over all folds to select the best architecture.The validation set is only used to tune hyper-parameters and select the optimal architecture. Afterwards, average of Mean Squared Error (MSE) over all folds is calculated on validation set to select the best hyper-parameters for each architecture. σ. The lowest errors are highlighted in bold.After selecting a model with the lowest MSE for each architecture, average of MSE on a test set is calculated for evaluation purposes. Similar to , only noAlthough ConvLSTM validation error is higher than other models, this architecture generalizes better for the test set and achieves the highest accuracy considering all the phases. The main reason of a high standard deviation in groundtruth is the Baxter’s gripper vibration. Even though the experiments are repeated with the same configuration, the environment is not fully controlled to evaluate the sensor in a practical scenario. Besides the vibration, the object size also plays an important role in differences between experiments. Silicone material has a highly non-linear deformation in different phases due to the changes in the contact force and objects size. Most of research in the literature see  considerThe results indicate that the accuracy of the estimated force is very promising for the grasping phase whereas all three LSTM-based networks achieve similar results. Due to the elasticity of the silicone membrane, errors tend to be more significant during the holding and releasing phases. Also, the difference between accuracy of different network architectures increases continuously towards the end of releasing phase. Furthermore, the non-linearity of the silicone behaviourbehavior creates a variable time lag between the F/T sensor and the proposed sensor. In order to investigate this problem, we perform Dynamic Time Warping (DTW) and calculate the distance between the estimated force and groundtruth in different phases. To measure similarity of distributions between the estimated force and the F/T sensor, Bhattacharyya distance is considered for each phase of the grasp. As presented in In As demonstrated in In this paper, we proposed a novel methodology to estimate the contact force dynamically. A neuromorphic camera (DVS) is used to capture intensity changes in the contact area. A novel dynamic approach is proposed to estimate the contact force for size-variant objects. The main challenge of force estimation for shape-variant objects is different contact area geometry under similar amount of applied force. We demonstrated that LSTM-based networks learn to relate the contact area size to the corresponding contact force over time.Three LSTM-based networks are developed and implemented to estimate the contact force based on history of changes in every pixel considering both spatial and temporal features. The proposed sensor is validated on Baxter robot for three bolts with different sizes. ConvLSTM achieved the best results, specifically MSE = 0.064 N for estimating the contact force in the grasping phase and MSE = 0.082 N in the holding phase, despite the inevitable vibrations. The sensor has a low logical latency of 10 ms which is suitable for the real-time grasping applications. The main advantage of the proposed approach is the combination of convolutional networks with recurrent layers which enables the sensor to estimate the contact force based on the object size relatively. The ConvLSTM architecture learns objects geometry in early frames and estimate the contact force during a grasp.For future work, synthetic data generation and augmentation techniques will be investigated to to increase the variability and the size of the training dataset and consequently increase the network generalization for the contact force measurements when an unknown object is grasped.


Background: The aim of this study was to investigate differences in static and dynamic plantar pressure and other foot geometry variables between female Olympic-style weightlifters and an age- and sex-matched control group. Methods: The study involved 24 national-level competitive weightlifters and 24 physical education students. Leg dominance was determined and baropodometry was used to assess plantar pressure and foot posture during quiet standing and walking. For all variables basic descriptive statistics were calculated (mean ± standard deviation). Student’s t test was used to compare the between-group differences. Spearman’s rank correlation coefficients were calculated to determine the association between BMI (Body Mass Index) and average and peak plantar pressure. Results: No significant differences were observed in plantar pressure distribution between the two groups. A moderate correlation was found between BMI and non-dominant limb peak and average plantar pressure in the group of weightlifters in the static condition and in the control group in the dynamic condition. Conclusions: Olympic-style weightlifting may affect plantar pressure distribution and foot posture in female weightlifters. BMI may also correlate with peak and average plantar pressure in this population. Further research is needed to determine if Olympic-style weightlifting may affect plantar pressure distribution and foot posture in female weightlifters. Professional involvement in sports is associated with overtraining, which can adversely affect the human skeletal system. Athletes are at risk of chronic injuries and overuse syndrome induced by excessive training loads or the repetitive use of specific muscle groups, the most common being the knee joint 28%) and ankle and knee joints 21%). Disorders of the feet are one of the factors that can increase the risk of injury [%. Disord8% and anFemale Olympic-style weightlifting involves the snatch and the clean and jerk. Both require a very high level of coordination and proper technique during execution ,7,8. TheBaropodometric analysis was used to assess foot posture and plantar pressure in dynamic and static conditions in female weightlifters and age- and sex-matched controls.The weightlifting group involved 24 female participants with a minimum two years of experience in competitive weightlifting selected during an Under-23 (years of age) national championship. This group trained 4–6 times per week with each training session lasting 120 min. The control group consisted of 24 female students of the Department of Physiotherapy at a physical education university. They declared that they were not involved in any sport or did not perform strenuous physical activity. All were free of any musculoskeletal injury or dysfunction and provided written informed consent to participate in the study. Basic anthropometric characteristics for both groups are presented in A FreeMed baropodometric platform was used to assess plantar pressure and foot geometry. All measures were processed with the integrated FreeStep software. Leg dominance was determined according to the Bogdanowicz test. This method involves ascending a step on a signal. The leg used by the participant to take the first step is treated as the dominant limb .Testing was first performed in the static condition and then in the dynamic condition with no rest interval. While analysis of the feet in the static condition is considered acceptable, the literature recommends the concomitant application of dynamic testing to better reflect the functional status of the feet .www.koordynacja.com.pl). Variables collected in both conditions included dominant and non-dominant limb peak and average plantar pressure, forefoot and rearfoot plantar pressure distribution, the calcaneus angle as an equivalent of the gamma heel angle and plantar axis [Both tests were performed barefoot with both eyes open. Testing in the static condition involved standing quietly for 5 s on the baropodometric platform with the feet parallel and arms resting along the body. For the dynamic condition, the participant walked at a normal pace from one end of the platform and back approximately four times to allow each foot to register on central part of the platform at least twice . The data set was assessed for normality using the Shapiro-Wilk test. Basic descriptive statistics (mean ± standard deviation) were calculated for all variables. Student’s ocedures .The majority of the participants in both groups showed neutral pronation, with overpronation the least common foot posture . Mean caMean calcaneus angle and plantar axis measured in the dynamic condition were of greater magnitude in the group of weightlifters for the dominant limb . The calAmong professional athletes, the musculoskeletal system is subject to significant loads over the course of their career. Efforts made to minimize the risk of injury should involve frequent monitoring of the musculoskeletal system and in particular the feet, as they provide a base of support for the entire body . SeveralOlympic-style weightlifting may affect plantar pressure distribution and foot posture in female weightlifters. No significant between-group differences were observed among studied variables. BMI may also correlate with peak and average plantar pressure in this population. Further research is needed to determine if Olympic-style weightlifting may affect plantar pressure distribution and foot posture in female weightlifters.The present findings may contribute to the reduction of injuries associated with overuse of the musculoskeletal system and the occurrence of pain among individuals actively involved in sports, which can be associated with the abnormal transfer of load via the kinematic chain from the feet towards the feet, knees, hips, and spine. These findings can also be of importance for coaches and weightlifters to ensure the safe development of the musculoskeletal system and effective training programs ,31,34,35


A receptors on corticotropin-releasing factor (CRF) expression at the PVN. Various manual therapies such as acupuncture, transcutaneous electrical nerve stimulation (TENS), and massage initiate the stimulation of somatosensory neurons of the body. It is well-known that TENS simulates OT expression, while it inhibits CRF expression at the PVN following chronic stress loading in rodents. Upregulation of OT expression at the hypothalamus is activated by the somatosensory stimulation, which is mediated via the spinothalamic pathway . Thus, somatosensory stimulation is beneficial in treating stress-associated symptoms. Hypothalamic OT is associated with the social behaviors, including maternal care and affiliation. Childhood neglect and/or child abuse are severely responsible for deleterious long-term effects on the cognitive/social activity and behavioral development. At parturition, a profound amount of OT is released into the systemic circulation in response to vaginal and cervical stimulation caused by the body of fetus, which induces the onset of maternal behavior. Peridural anesthesia effectively impairs the sensitivity to vaginal and cervical stimulation at parturition. OT levels in cerebrospinal fluid is significantly reduced following peridural anesthesia. The vaginal delivery mothers had significantly more OT pulses than the caesarian section (CS) mothers. Due to low levels of endogenous OT, maternal behavior could be interrupted by epidural anesthesia and CS at parturition because of the reduction of the usual sensory input from the genitalia.It has been shown that various types of stress initiate different physiological and neuroendocrine disorders. Oxytocin (OT) is mainly produced in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus. Hypothalamic OT has antistress effects and attenuates the hypothalamic–pituitary–adrenal (HPA) axis. One mechanism behind the antistress effects of OT is mediated through the inhibition from GABA Oxytocin (OT) is mainly produced in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus. In addition to the female reproductive function, OT plays important roles in attenuating stress responses and anxiety  mRNA expression at the hypothalamus, resulting in antistress and anti-anxiety effects  and LC (locus coeruleus), which then can influence the noradrenergic neurons projecting to the CRF neurons in the hypothalamus  tract in rodents. Accelerated colonic transit and delayed gastric emptying induced by stress are attenuated by intracerebroventricular (icv)-injection of OT in rodents , brain stem, etc., via collateral connections , and massage. Acupuncture utilizes the procedure of insertion of sharp thin needles into the skin and underlying muscle layer. Inserted needles are sometimes stimulated by electricity under various frequencies . In contrast to acupuncture, TENS does not involve the procedure of needle insertion; instead, electrodes are placed on the skin and stimulated by electricity with various frequencies (1–100 Hz).Acupuncture and/or TENS have been applied for treating various GI diseases, including constipation, diarrhea, functional dyspepsia (FD), and irritable bowel syndrome (IBS)  in anesthetized rats . In addition, we showed that TENS increased the number of OT-immunopositive neurons, while it decreased the number of CRF-immunopositive neurons at the hypothalamus following restraint stress in rats  was decreased in rats .Clinical trials showed that acupuncture is effective to treat the symptoms of patients with PTSD. People diagnosed with PTSD were divided into two groups: either an acupuncture treatment group or a cognitive–behavioral therapy (CBD) group. The study demonstrated that the acupuncture group provided a significant effect to improve their symptoms, compared with CBT group in PTSD patients  demonstrated that the effect of OT spray on anxiety and depressive symptoms is still inconclusive . In addition, the sustained close relationship with their mothers is essential to maintain the body temperature for survival.The bonding between the mother and infant is important in its influence on the infant's future. Child neglect and/or abuse during early life of the infant may develop abnormal mother–infant bonding systems, which may cause inappropriate social functions and/or behavioral activity later in life  or the late peridural anesthesia procedure (LP). When peridural anesthesia was performed at the late stage of parturition (LP), maternal behavior was only slightly altered, compared with controls . In contrast, maternal behavior was severely impaired in the case of EP.Seven out of eight mothers failed to show any interest to their newborn babies in 30 min after the delivery, in the case of EP   on request was a turning point in the history of childbirth. Today, in many countries, most women opt to give birth by elective CS on request, which may cause a reduction in releasing endogenous OT.Is there any difference of hormonal pattern of OT between the women delivered by the vaginal route and the women delivered by emergency CS? Does the different pattern of OT release show any relation to the duration of breastfeeding?To answer these questions, Nissen et al.  comparedThe plasma level of OT was significantly higher in the vaginal delivery mothers than those of the CS mothers. Furthermore, the CS mothers showed no significant rise in prolactin levels at 20–30 min after the onset of breastfeeding (Nissen et al., However, it remains unknown whether CS women with reduced OT release have problems associated with mother–infant bonding. Further clinical studies are needed to investigate whether CS impairs the development of maternal behavior in humans (Takahashi et al., The author confirms being the sole contributor of this work and has approved it for publication.The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Congenital radioulnar synostosis is a rare developmental skeletal malformation of the upper limb, characterized by the fusion of the proximal ends of the radius and ulna from birth. The failure of prenatal longitudinal segmentation of the adjacent radius and ulna results in a fibrous bony bridge between the radius and ulna. We present a 23-year-old female who presented with pain and restricted mobility of the left elbow joint for 7 years. A plain X-ray was performed for the patient, revealing a diagnosis of congenital radio-ulnar synostosis. Careful evaluation of the anatomical relations and spatial orientation of bony structures is required for the diagnosis and treatment of such cases. Congenital radioulnar synostosis (CRUS) is an uncommon developmental skeletal malformation of the upper limb, characterized by a fusion of the proximal ends of the radius and ulna from birth . In factClinical features of CRUS include restricted movements of the forearm, especially rotation i.e. supination and pronation . HoweverMild deformity, minimal functional deficit and developed adjustments to activities are contraindications to surgical procedures . SurgeryWe are reporting the case of a 23-year-old married Saudi female patient, who presented to the King Khalid Hospital and Prince Sultan Centre for Health Services with pain and restricted mobility of the left elbow joint. The patient reported that this restriction in mobility significantly impacted her quality of life, in that she was unable to continue working as a seamstress or perform activities of daily living such as household chores or nursing her infant. Furthermore, she had experienced intermittent mechanical pain at the left elbow joint for the past 7 years, but the frequency and intensity of the pain had intensified ever since she started nursing her child 4 months ago. The character of the pain was reported to be dull, constant in nature and localized to the anterolateral aspect of the elbow joint. It was exaggerated upon movement and relieved upon rest. There was associated stiffness that lasted throughout the day. There was no radiation and no associated neurological symptoms such as numbness or weakness. The patient was not on any long-term medications and had minimal relief of her symptoms with oral paracetamol and topical NSAID  ointment.Neither positive family history of musculoskeletal deformities nor tobacco or alcohol consumption were performed. A review of her other systems revealed no gross abnormalities. On physical examination, there were no gross abnormalities of the overlying skin or elbow joint when inspected. Upon passive and active movement of the leftelbow joint, significant restriction in supination and pronation were observed. The patient informed that she was cognizant of this restriction since she was young. The neurovascular status of the limb was intact. A plain X-ray was performed for the patient, revealing a diagnosis of congenital radio-ulnar synostosis. The plain X-ray and reconstructed images are delineated in th week of gestation that results in a persistent bridge of tissue [At five weeks of gestation, the humours, radius and ulna are continuous with each other and joined together by a common perichondrium . Then atf tissue . The perf tissue . It has f tissue . This paf tissue . Howeverf tissue , derotatf tissue .Careful thorough examination of upper limb at birth may offer some surgical correction of congenital radioulnar synostosis such as derotational osteotomy.