ResearchPad - engineering-and-technology https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Evaluation of residue management practices on barley residue decomposition]]> https://www.researchpad.co/article/elastic_article_13875 Optimizing barley (hordeum vulgare L.) production in Idaho and other parts of the Pacific Northwest (PNW) should focus on farm resource management. The effect of post-harvest residue management on barley residue decomposition has not been adequately studied. Thus, the objective of this study was to determine the effect of residue placement (surface vs. incorporated), residue size (chopped vs. ground-sieved) and soil type (sand and sandy loam) on barley residue decomposition. A 50-day(d) laboratory incubation experiment was conducted at a temperature of 25°C at the Aberdeen Research and Extension Center, Aberdeen, Idaho, USA. Following the study, a Markov-Chain Monte Carlo (MCMC) modeling approach was applied to investigate the first-order decay kinetics of barley residue. An accelerated initial flush of residue carbon(C)-mineralization was measured for the sieved (Day 1) compared to chopped (Day 3 to 5) residues for both surface incorporated applications. The highest evolution of carbon dioxide (CO2)-C of 8.3 g kg-1 dry residue was observed on Day 1 from the incorporated-sieved application for both soils. The highest and lowest amount of cumulative CO2-C released and percentage residue decomposed over 50-d was observed for surface-chopped (107 g kg-1 dry residue and 27%, respectively) and incorporated-sieved (69 g kg-1 dry residue and 18%, respectively) residues, respectively. There were no significant differences in C-mineralization from barley residue based on soil type or its interactions with residue placement and size (p >0.05). The largest decay constant k of 0.0083 d-1 was calculated for surface-chopped residue where the predicted half-life was 80 d, which did not differ from surface sieved or incorporated chopped. In contrast, incorporated-sieved treatments only resulted in a k of 0.0054 d-1 and would need an additional 48 d to decompose 50% of the residue. Future residue decomposition studies under field conditions are warranted to verify the residue C-mineralization and its impact on residue management.

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<![CDATA[Early budget impact analysis on magnetic seed localization for non-palpable breast cancer surgery]]> https://www.researchpad.co/article/elastic_article_13866 Current localization techniques used in breast conserving surgery for non-palpable tumors show several disadvantages. Magnetic Seed Localization (MSL) is an innovative localization technique aiming to overcome these disadvantages. This study evaluated the expected budget impact of adopting MSL compared to standard of care.MethodsStandard of care with Wire-Guided Localization (WGL) and Radioactive Seed Localization (RSL) use was compared with a future situation gradually adopting MSL next to RSL or WGL from a Dutch national perspective over 5 years (2017–2022). The intervention costs for WGL, RSL and MSL and the implementation costs for RSL and MSL were evaluated using activity-based costing in eight Dutch hospitals. Based on available list prices the price of the magnetic seed was ranged €100-€500.ResultsThe intervention costs for WGL, RSL and MSL were respectively: €2,617, €2,834 and €2,662 per patient and implementation costs were €2,974 and €26,826 for MSL and RSL respectively. For standard of care the budget impact increased from €14.7m to €16.9m. Inclusion of MSL with a seed price of €100 showed a budget impact of €16.7m. Above a price of €178 the budget impact increased for adoption of MSL, rising to €17.6m when priced at €500.ConclusionMSL could be a cost-efficient localization technique in resecting non-palpable tumors in the Netherlands. The online calculation model can inform adoption decisions internationally. When determining retail price of the magnetic seed, cost-effectiveness should be considered. ]]> <![CDATA[A network analysis of research productivity by country, discipline, and wealth]]> https://www.researchpad.co/article/elastic_article_13855 Research productivity has been linked to a country’s intellectual and economic wealth. Further analysis is needed to assess the association between the distribution of research across disciplines and the economic status of countries.MethodsBy using 55 years of data, spanning 1962 to 2017, of Elsevier publications across a large set of research disciplines and countries globally, this manuscript explores the relationship and evolution of relative research productivity across different disciplines through a network analysis. It also explores the associations of those with economic productivity categories, as measured by the World Bank economic classification. Additional analysis of discipline similarities is possible by exploring the cross-country evolution of those disciplines.ResultsResults show similarities in the relative importance of research disciplines among most high-income countries, with larger idiosyncrasies appearing among the remaining countries. This group of high-income countries shows similarities in the dynamics of the relative distribution of research productivity over time, forming a stable research productivity cluster. Lower income countries form smaller, more independent and evolving clusters, and differ significantly from each other and from higher income countries in the relative importance of their research emphases. Country-based similarities in research productivity profiles also appear to be influenced by geographical proximity.ConclusionsThis new form of analyses of research productivity, and its relation to economic status, reveals novel insights to the dynamics of the economic and research structure of countries. This allows for a deeper understanding of the role a country’s research structure may play in shaping its economy, and also identification of benchmark resource allocations across disciplines for developing countries. ]]> <![CDATA[Comparability of modern contraceptive use estimates between a face-to-face survey and a cellphone survey among women in Burkina Faso]]> https://www.researchpad.co/article/elastic_article_13849 The proliferation of cell phone ownership in Sub-Saharan Africa (SSA) presents the opportunity to collect public health indicators at a lower cost compared to face-to-face (FTF) surveys. This analysis assesses the equivalence of modern contraceptive prevalence estimates between a nationally representative FTF survey and a cell phone survey using random digit dialing (RDD) among women of reproductive age in Burkina Faso.MethodsWe analyzed data from two surveys conducted in Burkina Faso between December 2017 and May 2018. The FTF survey conducted by Performance Monitoring and Accountability (PMA2020) comprised a nationally representative sample of 3,556 women of reproductive age (15–49 years). The RDD survey was conducted using computer-assisted telephone interviewing and included 2,379 women of reproductive age.ResultsCompared to FTF respondents, women in the RDD sample were younger, were more likely to have a secondary degree and to speak French. RDD respondents were more likely to report using modern contraceptive use (40%) compared to FTF respondents (26%) and the difference remained unchanged after applying post-stratification weights to the RDD sample (39%). This difference surpassed the equivalence margin of 4%. The RDD sample also produced higher estimates of contraceptive use than the subsample of women who owned a phone in the FTF sample (32%). After adjusting for women’s sociodemographic factors, the odds of contraceptive use were 1.9 times higher (95% CI: 1.6–2.2) in the RDD survey compared to the FTF survey and 1.6 times higher (95% CI: 1.3–1.8) compared to FTF phone owners.ConclusionsModern contraceptive prevalence in Burkina Faso is over-estimated when using a cell phone RDD survey, even after adjusting for a number of sociodemographic factors. Further research should explore causes of differential estimates of modern contraceptive use by survey modes. ]]> <![CDATA[Inferring a simple mechanism for alpha-blocking by fitting a neural population model to EEG spectra]]> https://www.researchpad.co/article/elastic_article_13836 One of the most striking features of the human electroencephalogram (EEG) is the presence of neural oscillations in the range of 8-13 Hz. It is well known that attenuation of these alpha oscillations, a process known as alpha blocking, arises from opening of the eyes, though the cause has remained obscure. In this study we infer the mechanism underlying alpha blocking by fitting a neural population model to EEG spectra from 82 different individuals. Although such models have long held the promise of being able to relate macroscopic recordings of brain activity to microscopic neural parameters, their utility has been limited by the difficulty of inferring these parameters from fits to data. Our approach involves fitting eyes-open and eyes-closed EEG spectra in a way that minimizes unnecessary differences in model parameters between the two states. Surprisingly, we find that changes in just one parameter, the level of external input to the inhibitory neurons in cortex, is sufficient to explain the attenuation of alpha oscillations. This indicates that opening of the eyes reduces alpha activity simply by increasing external inputs to the inhibitory neurons in the cortex.

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<![CDATA[Retrospectively ECG-gated helical vs. non-ECG-synchronized high-pitch CTA of the aortic root for TAVI planning]]> https://www.researchpad.co/article/elastic_article_13825 Multidetector computed tomography (MDCT) plays a key role in patient assessment prior to transcatheter aortic valve implantation (TAVI). However, to date no consensus has been established on what is the optimal pre-procedural imaging protocol. Variability in pre-TAVI acquisition protocols may lead to discrepancies in aortic annulus measurements and may potentially influence prosthesis size selection.PurposeThe current study evaluates the magnitude of differences in aortic annulus measurements using max-systolic, end-diastolic, and non-ECG-synchronized imaging, as well as the impact of method on prosthesis size selection.Material and methodsFifty consecutive TAVI-candidates, who underwent retrospectively-ECG-gated CT angiography (CTA) of the aortic root, directly followed by non-ECG-synchronized high-pitch CT of the entire aorta, were retrospectively included. Aortic root dimensions were assessed at each 10% increment of the R-R interval (0–100%) and on the non-ECG-synchronized scan. Dimensional changes within the cardiac cycle were evaluated using a 1-way repeated ANOVA. Agreement in measurements between max-systole, end-diastole and non-ECG-synchronized scans was assessed with Bland-Altman analysis.ResultsMaximal dimensions of the aortic root structures and minimum annulus-coronary ostia distances were measured during systole. Max-systolic measurements were significantly and substantially larger than end-diastolic (p<0.001) and non-ECG-synchronized measurements (p<0.001). Due to these discrepancies, the three methods resulted in the same prosthesis size selection in only 48–62% of patients.ConclusionsThe systematic differences between max-systolic, end-diastolic and non-ECG-synchronized measurements for relevant aortic annular dimensions are both statistically significant and clinically relevant. Imaging strategy impacts prosthesis size selection in nearly half the TAVI-candidates. End-diastolic and non-ECG-synchronized imaging does not provide optimal information for prosthesis size selection. Systolic image acquisition is necessary for assessment of maximal annular dimensions and minimum annulus-coronary ostia distances. ]]> <![CDATA[Mechanical characterization of PVA hydrogels’ rate-dependent response using multi-axial loading]]> https://www.researchpad.co/article/elastic_article_13820 The time-dependent properties of rubber-like synthesized and biological materials are crucial for their applications. Currently, this behavior is mainly measured using axial tensile test, compression test, or indentation. Limited studies performed on using multi-axial loading measurements of time-dependent material behavior exist in the literature. Therefore, the aim of this study is to investigate the viscoelastic response of rubber-like materials under multi-axial loading using cavity expansion and relaxation tests. The tests were performed on PVA hydrogel specimens. Three hyperelasitc models and one term Prony series were used to characterize the viscoelastic response of the hydrogels. Finite element (FE) simulations were performed to verify the validity of the calibrated material coefficients by reproducing the experimental results. The excellent agreement between the experimental, analytical and numerical data proves the capability of the cavity expansion technique to measure the time-dependent behavior of viscoelastic materials.

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<![CDATA[Is transjugular insertion of a temporary pacemaker a safe and effective approach?]]> https://www.researchpad.co/article/elastic_article_13814 Temporary pacemakers (TPMs) are usually inserted in an emergency situation. However, there are few reports available regarding which route of access is best or what the most preferred approach is currently in tertiary hospitals. This study aimed to compare procedure times, complication rates, and indications for temporary pacing between the transjugular and transfemoral approaches to TPM placement. We analyzed consecutive patients who underwent TPM placement. Indications; procedure times; and rates of complications including localized infection, any bleeding, and pacing wire repositioning rates were analyzed. A total of 732 patients (361 treated via the transjugular approach and 371 treated via the transfemoral approach) were included. Complete atrioventricular block was the most common cause of TPM placement in both groups, but sick sinus syndrome was especially common in the transjugular approach group. Separately, procedure time was significantly shorter in the transjugular approach group (9.0 ± 8.0 minutes vs. 11.9 ± 9.7 minutes; P < 0.001). Overall complication rates were not significantly different between the two groups, and longer duration of temporary pacing was a risk factor for repositioning. The risk of reposition was significantly increased when the temporary pacing was continued more than 5 days and 3 days in the transjugular approach group and the transfemoral approach group, respectively. The transjugular approach should be considered if the TPM is required for more than 3 days.

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<![CDATA[Instigation of indigenous thermophilic bacterial consortia for enhanced oil recovery from high temperature oil reservoirs]]> https://www.researchpad.co/article/elastic_article_13812 The purpose of the study involves the development of an anaerobic, thermophilic microbial consortium TERIK from the high temperature reservoir of Gujarat for enhance oil recovery. To isolate indigenous microbial consortia, anaerobic baltch media were prepared and inoculated with the formation water; incubated at 65°C for 10 days. Further, the microbial metabolites were analyzed by gas chromatography, FTIR and surface tension. The efficiency of isolated consortia towards enhancing oil recovery was analyzed through core flood assay. The novelty of studied consortia was that, it produces biomass (600 mg/l), bio-surfactant (325 mg/l), and volatile fatty acids (250 mg/l) at 65°C in the span of 10 days, that are adequate to alter the surface tension (70 to 34 mNm -1) and sweep efficiency of zones facilitating the displacement of oil. TERIK was identified as Clostridium sp. The FTIR spectra of biosurfactant indicate the presence of N-H stretch, amides and polysaccharide. A core flooding assay was designed to explore the potential of TERIK towards enhancing oil recovery. The results showed an effective reduction in permeability at residual oil saturation from 2.14 ± 0.1 to 1.39 ± 0.05 mD and 19% incremental oil recovery.

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<![CDATA[Chloroplast genomes of Rubiaceae: Comparative genomics and molecular phylogeny in subfamily Ixoroideae]]> https://www.researchpad.co/article/elastic_article_11231 In Rubiaceae phylogenetics, the number of markers often proved a limitation with authors failing to provide well-supported trees at tribal and generic levels. A robust phylogeny is a prerequisite to study the evolutionary patterns of traits at different taxonomic levels. Advances in next-generation sequencing technologies have revolutionized biology by providing, at reduced cost, huge amounts of data for an increased number of species. Due to their highly conserved structure, generally recombination-free, and mostly uniparental inheritance, chloroplast DNA sequences have long been used as choice markers for plant phylogeny reconstruction. The main objectives of this study are: 1) to gain insight in chloroplast genome evolution in the Rubiaceae (Ixoroideae) through efficient methodology for de novo assembly of plastid genomes; and, 2) to test the efficiency of mining SNPs in the nuclear genome of Ixoroideae based on the use of a coffee reference genome to produce well-supported nuclear trees. We assembled whole chloroplast genome sequences for 27 species of the Rubiaceae subfamily Ixoroideae using next-generation sequences. Analysis of the plastid genome structure reveals a relatively good conservation of gene content and order. Generally, low variation was observed between taxa in the boundary regions with the exception of the inverted repeat at both the large and short single copy junctions for some taxa. An average of 79% of the SNP determined in the Coffea genus are transferable to Ixoroideae, with variation ranging from 35% to 96%. In general, the plastid and the nuclear genome phylogenies are congruent with each other. They are well-resolved with well-supported branches. Generally, the tribes form well-identified clades but the tribe Sherbournieae is shown to be polyphyletic. The results are discussed relative to the methodology used and the chloroplast genome features in Rubiaceae and compared to previous Rubiaceae phylogenies.

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<![CDATA[Stereoscopic optimization of industrial structure of the equipment manufacturing industry from the perspective of collaborative emissions reduction: Evidence from China]]> https://www.researchpad.co/article/elastic_article_11230 Equipment manufacturing industry is one of the major industries of the Chinese economy. Previous researches have revealed that the industry has dilemmas of unreasonable industrial structure and high pollution. Using the data of 30 provinces in 2006-2015 in China, this study calculated a comprehensive pollution indicator when estimating the possible pollution reduction brought by the optimization of industrial structure and then evaluated the reasonable level of capital allocation of provinces and industries by using the methods of nonlinear programming and stochastic frontier method. Under the target of collaborative emission reduction, the results show that the optimized output of China’s equipment manufacturing industry could be increased by 5.42%, the energy intensity could be reduced by about 10.4%, and the comprehensive emission intensity could be reduced by about 7.47%. Due to the industry heterogeneity and regional heterogeneity, industrial capacity should be transferred between industries and regions. Since the capital investment in the equipment manufacturing industry is significantly mismatched between industries and regions, the capital allocation of provincial industries in China needs to be adjusted properly. This study provides theoretically and practically reference for collaborative pollution reduction, industry restructure, spatial layout and capital investment, which contributes to achieving the stereoscopic optimization of equipment manufacturing industry.

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<![CDATA[Proficiency based progression simulation training significantly reduces utility strikes; A prospective, randomized and blinded study]]> https://www.researchpad.co/article/elastic_article_7871 We evaluated a simulation-based training curriculum with quantitatively defined performance benchmarks for utility workers location and excavation of utility services.BackgroundDamaging buried utilities is associated with considerable safety risks to workers and substantial cost to employers.MethodsIn a prospective, randomized and blinded study we assessed the impact of Proficiency Based Progression (PBP) simulation training on the location and excavation of utility services work.ResultsPBP simulation training reduced performance errors (33%, p = 0.006) in comparison a standard trained group. When implemented across all workers in the same division there was a 35–61% reduction in utility strikes (p = 0.028) and an estimated cost saving of £116,000 –£2,175,000 in the 12 months (47,000 work hours) studied.ConclusionsThe magnitude of the training benefit of PBP simulation training in the utilities sector appears to be the same as it is in surgery, cardiology and procedure-based medicine.ApplicationQuality-assured utility worker simulation training significantly reduces utility damage and associated costs. ]]> <![CDATA[Substantial improvement of tetraene macrolide production in <i>Streptomyces diastatochromogenes</i> by cumulative drug resistance mutations]]> https://www.researchpad.co/article/elastic_article_7861 Tetraene macrolides remain one of the most reliable fungicidal agents as resistance of fungal pathogens to these antibiotics is relatively rare. The modes of action and biosynthesis of polyene macrolides had been the focus of research over the past few years. However, few studies have been carried out on the overproduction of polyene macrolides. In the present study, cumulative drug-resistance mutation was used to obtain a quintuple mutant G5-59 with huge tetraene macrolide overproduction from the starting strain Streptomyces diastatochromogenes 1628. Through DNA sequence analysis, the mutation points in the genes of rsmG, rpsL and rpoB were identified. Additionally, the growth characteristic and expression level of tetrRI gene (belonging to the large ATP binding regulator of LuxR family) involved in the biosynthesis of tetraene macrolides were analyzed. As examined with 5L fermentor, the quintuple mutant G5-59 grew very well and the maximum productivity of tetramycin A, tetramycin P and tetrin B was as high as 1735, 2811 and 1500 mg/L, which was 8.7-, 16- and 25-fold higher than that of the wild-type strain 1628, respectively. The quintuple mutant G5-59 could be useful for further improvement of tetraene macrolides production at industrial level.

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<![CDATA[Towards universal coverage for nutrition services in children under five years—A descriptive analysis of the capacity of level one hospitals to provide nutrition services in five provinces of Zambia]]> https://www.researchpad.co/article/elastic_article_7846 Malnutrition continues to be a major public health challenge in Zambia. To effectively address this, health systems must be well strengthened to deliver an effective continuum of care. This paper examines health systems issues and services in relation to nutritional support to children under five years, in order to identify gaps and propose interventions towards universal coverage of essential nutrition services.MethodsThis analysis utilized data from a cross sectional mixed-methods study on factors associated with Severe Acute Malnutrition (SAM) in under-five children to assess health facility nutrition services on offer at select level-one hospitals in five out of ten provinces in Zambia. Stata version 13 was used for analysis. We conducted univariate analysis to assess nutrition services offered, functionality of equipment and tools, availability of human resource and human resource development, and availability of drugs used for assessment and management of nutrition-related health outcomes.ResultsWe found large variations in the level of nutrition services on offer across districts and provinces. Eighty-eight percent of all the hospitals sampled provided group nutrition counseling and 92% of the hospitals in our sample offered individual nutrition counseling to their clients. Overall, the existence of referral and counter-referral systems between the Community Based Volunteers and hospitals were the lowest among all services assessed at 48% and 58% respectively. We also found inadequate numbers of human resource across all cadres with an exception of nutritionists as recommended by the Ministry of Health.ConclusionsThis study has revealed a number of gaps in the health system and health service delivery that requires to be addressed; most notably, a lack of tools, policies and guidelines, drugs and health specialists to help care for malnourished infants and children. Our findings also reveal inadequate referral systems between the community and health facilities in the management of severe acute malnutrition. Achieving universal coverage for nutrition services in Zambia will require a lot more attention to the health systems issues found in this study. ]]> <![CDATA[Mechanism to prevent the abuse of IPv6 fragmentation in OpenFlow networks]]> https://www.researchpad.co/article/elastic_article_7717 OpenFlow makes a network highly flexible and fast-evolving by separating control and data planes. The control plane thus becomes responsive to changes in topology and load balancing requirements. OpenFlow also offers a new approach to handle security threats accurately and responsively. Therefore, it is used as an innovative firewall that acts as a first-hop security to protect networks against malicious users. However, the firewall provided by OpenFlow suffers from Internet protocol version 6 (IPv6) fragmentation, which can be used to bypass the OpenFlow firewall. The OpenFlow firewall cannot identify the message payload unless the switch implements IPv6 fragment reassembly. This study tests the IPv6 fragmented packets that can evade the OpenFlow firewall, and proposes a new mechanism to guard against attacks carried out by malicious users to exploit IPv6 fragmentation loophole in OpenFlow networks. The proposed mechanism is evaluated in a simulated environment by using six scenarios, and results exhibit that the proposed mechanism effectively fixes the loophole and successfully prevents the abuse of IPv6 fragmentation in OpenFlow networks.

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<![CDATA[Life within a limited radius: Investigating activity space in women with a history of child abuse using global positioning system tracking]]> https://www.researchpad.co/article/elastic_article_7709 Early experiences of childhood sexual or physical abuse are often associated with functional impairments, reduced well-being and interpersonal problems in adulthood. Prior studies have addressed whether the traumatic experience itself or adult psychopathology is linked to these limitations. To approach this question, individuals with posttraumatic stress disorder (PTSD) and healthy individuals with and without a history of child abuse were investigated. We used global positioning system (GPS) tracking to study temporal and spatial limitations in the participants’ real-life activity space over the course of one week. The sample consisted of 228 female participants: 150 women with PTSD and emotional instability with a history of child abuse, 35 mentally healthy women with a history of child abuse (healthy trauma controls, HTC) and 43 mentally healthy women without any traumatic experiences in their past (healthy controls, HC). Both traumatized groups—i.e. the PTSD and the HTC group—had smaller movement radii than the HC group on the weekends, but neither spent significantly less time away from home than HC. Some differences between PTSD and HC in movement radius seem to be related to correlates of PTSD psychopathology, like depression and physical health. Yet group differences between HTC and HC in movement radius remained even when contextual and individual health variables were included in the model, indicating specific effects of traumatic experiences on activity space. Experiences of child abuse could limit activity space later in life, regardless of whether PTSD develops.

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<![CDATA[Image-quality metric system for color filter array evaluation]]> https://www.researchpad.co/article/elastic_article_7704 A modern color filter array (CFA) output is rendered into the final output image using a demosaicing algorithm. During this process, the rendered image is affected by optical and carrier cross talk of the CFA pattern and demosaicing algorithm. Although many CFA patterns have been proposed thus far, an image-quality (IQ) evaluation system capable of comprehensively evaluating the IQ of each CFA pattern has yet to be developed, although IQ evaluation items using local characteristics or specific domain have been created. Hence, we present an IQ metric system to evaluate the IQ performance of CFA patterns. The proposed CFA evaluation system includes proposed metrics such as the moiré robustness using the experimentally determined moiré starting point (MSP) and achromatic reproduction (AR) error, as well as existing metrics such as color accuracy using CIELAB, a color reproduction error using spatial CIELAB, structural information using the structure similarity, the image contrast based on MTF50, structural and color distortion using the mean deviation similarity index (MDSI), and perceptual similarity using Haar wavelet-based perceptual similarity index (HaarPSI). Through our experiment, we confirmed that the proposed CFA evaluation system can assess the IQ for an existing CFA. Moreover, the proposed system can be used to design or evaluate new CFAs by automatically checking the individual performance for the metrics used.

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<![CDATA[Concept of an artificial muscle design on polypyrrole nanofiber scaffolds]]> https://www.researchpad.co/article/elastic_article_8464 Here we present the synthesis and characterization of two new conducting materials having a high electro-chemo-mechanical activity for possible applications as artificial muscles or soft smart actuators in biomimetic structures. Glucose-gelatin nanofiber scaffolds (CFS) were coated with polypyrrole (PPy) first by chemical polymerization followed by electrochemical polymerization doped with dodecylbenzensulfonate (DBS-) forming CFS-PPy/DBS films, or with trifluoromethanesulfonate (CF3SO3-, TF) giving CFS-PPy/TF films. The composition, electronic and ionic conductivity of the materials were determined using different techniques. The electro-chemo-mechanical characterization of the films was carried out by cyclic voltammetry and square wave potential steps in bis(trifluoromethane)sulfonimide lithium solutions of propylene carbonate (LiTFSI-PC). Linear actuation of the CFS-PPy/DBS material exhibited 20% of strain variation with a stress of 0.14 MPa, rather similar to skeletal muscles. After 1000 cycles, the creeping effect was as low as 0,2% having a good long-term stability showing a strain variation per cycle of -1.8% (after 1000 cycles). Those material properties are excellent for future technological applications as artificial muscles, batteries, smart membranes, and so on.

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<![CDATA[Confocal Raman microscopy to identify bacteria in oral subgingival biofilm models]]> https://www.researchpad.co/article/elastic_article_7675 The study of oral disease progression, in relation to the accumulation of subgingival biofilm in gingivitis and periodontitis is limited, due to either the ability to monitor plaque in vitro. When compared, optical spectroscopic techniques offer advantages over traditional destructive or biofilm staining approaches, making it a suitable alternative for the analysis and continued development of three-dimensional structures. In this work, we have developed a confocal Raman spectroscopy analysis approach towards in vitro subgingival plaque models. The main objective of this study was to develop a method for differentiating multiple oral subgingival bacterial species in planktonic and biofilm conditions, using confocal Raman microscopy. Five common subgingival bacteria (Fusobacterium nucleatum, Streptococcus mutans, Veillonella dispar, Actinomyces naeslundii and Prevotella nigrescens) were used and differentiated using a 2-way orthogonal Partial Least Square with Discriminant Analysis (O2PLS-DA) for the collected spectral data. In addition to planktonic growth, mono-species biofilms cultured using the ‘Zürich Model’ were also analyzed. The developed method was successfully used to predict planktonic and mono-species biofilm species in a cross validation setup. The results show differences in the presence and absence of chemical bands within the Raman spectra. The O2PLS-DA model was able to successfully predict 100% of all tested planktonic samples and 90% of all mono-species biofilm samples. Using this approach we have shown that Confocal Raman microscopy can analyse and predict the identity of planktonic and mono-species biofilm species, thus enabling its potential as a technique to map oral multi-species biofilm models.

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<![CDATA[Genetic algorithm-based personalized models of human cardiac action potential]]> https://www.researchpad.co/article/elastic_article_7669 We present a novel modification of genetic algorithm (GA) which determines personalized parameters of cardiomyocyte electrophysiology model based on set of experimental human action potential (AP) recorded at different heart rates. In order to find the steady state solution, the optimized algorithm performs simultaneous search in the parametric and slow variables spaces. We demonstrate that several GA modifications are required for effective convergence. Firstly, we used Cauchy mutation along a random direction in the parametric space. Secondly, relatively large number of elite organisms (6–10% of the population passed on to new generation) was required for effective convergence. Test runs with synthetic AP as input data indicate that algorithm error is low for high amplitude ionic currents (1.6±1.6% for IKr, 3.2±3.5% for IK1, 3.9±3.5% for INa, 8.2±6.3% for ICaL). Experimental signal-to-noise ratio above 28 dB was required for high quality GA performance. GA was validated against optical mapping recordings of human ventricular AP and mRNA expression profile of donor hearts. In particular, GA output parameters were rescaled proportionally to mRNA levels ratio between patients. We have demonstrated that mRNA-based models predict the AP waveform dependence on heart rate with high precision. The latter also provides a novel technique of model personalization that makes it possible to map gene expression profile to cardiac function.

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