ARTICLE | doi:10.20944/preprints202207.0247.v2
Subject: Engineering, Other Keywords: fault detection; retraction/extension (R/E) hydraulic system; bond graph-linear fractional trans-formation technique; interval analytic redundancy relations; uncertainty; fault signature matrix; residuals; thresholds
Online: 17 August 2022 (03:53:54 CEST)
Various factors, such as uncertainty of component parameters and uncertainty of sensor meas-urement values, contribute to the difficulty of fault detection in the landing gear retrac-tion/extension hydraulic system. In this paper, we introduce linear fractional transformation technology and uncertainty analysis theory for the construction of the diagnostic bond graph of the landing gear retraction/extension hydraulic system. In this way, interval analytical redundancy relations and fault signature matrix can be derived. Using the fault signature matrix, existing faults of the system can be preliminarily detected and isolated. Additionally, interval analytical re-dundancy relations can be used to detect system faults in detail, and cases analysis can be carried out to determine if the actuator is externally or internally leaky, and if the landing gear selector valve is reversing stuck. Compared to the traditional analytical redundancy relations, this method takes into account the negative factors of uncertainty; and compared to the traditional absolute diagnostic threshold, the interval diagnostic threshold is more accurate and sensitive.
ARTICLE | doi:10.20944/preprints202204.0184.v1
Subject: Engineering, Other Keywords: health assessment; landing gear retraction and extension hydraulic system; improved risk coefficient; fuzzy comprehensive evaluation; fault simulation; maintenance manual
Online: 20 April 2022 (04:52:38 CEST)
The health of the landing gear retraction and extension hydraulic system may be assessed using fuzzy comprehensive evaluation (FCE), however the traditional FCE method depends solely on human assessment by specialists, which is excessively subjective. To address the issue of excessive human subjective variables in the assessment, an improved FCE model based on enhanced risk coefficient is provided, which includes four consideration indexes: failure probability, failure severity, failure detection difficulty, and failure repair difficulty. To reduce subjective human judgment errors entirely due to expert experience, the improved FCE takes into account the likelihood of failure using a statistical method, the severity of failure using a fault simulation analysis based on the LMS Imagine.Lab AMESim simulation platform, and the difficulty of fault detection and repair using the aircraft manufacturer's professional maintenance information. As part of the evaluation model, the range of health assessment values and accompanying treatment methods are included, making it easier to implement on a daily basis in aircraft maintenance. As a final step, the simulation is evaluated and the simulated faults are calculated.
ARTICLE | doi:10.20944/preprints202106.0625.v1
Subject: Behavioral Sciences, Social Psychology Keywords: precision agriculture; agricultural extension; profitability; production quality; systematic review
Online: 25 June 2021 (15:52:08 CEST)
Precision agriculture (PA) is a holistic, sustainable, innovative systems approach that assists farmers in production management. Adopting PA could improve sustainable food security and community economic sustainability. Developing an understanding of PA adoption attributes is needed to assist extension practitioners to promote adoption and better understand the innovation adoption phenomena. A systematic review of literature was conducted to investigate PA adoption. Thirty-three publications were examined, and four themes were found among the reviewed publications. The results were interpreted using Rogers’ diffusion of innovations framework to address the research objectives. Of the reviewed literature, we found relative advantage and compatibility were two dominant attributes to strengthen the adoption of PA, and the complexity attribute was rarely used to promote the adoption of PA. This study shows that change agents do not fully use five attributes of innovation when they promote PA technology to stakeholders to adopt. Thus, we recommend studies from the agricultural extension specialists’ perspectives in the future may determine contributions to motivate farmers’ adoption of PA, in particular related to complexity.
ARTICLE | doi:10.20944/preprints202012.0198.v1
Subject: Behavioral Sciences, Applied Psychology Keywords: behavior change; fertilizer application; theory; systems science; sugarcane; social norms; extension services; agronomy; management practices.
Online: 8 December 2020 (10:06:35 CET)
Research focused on understanding wider systemic factors driving behavioral change is limited with a dominant focus on the role of individual farmer and psychosocial factors for farming practice change, including reducing fertilizer application in agriculture. Adopting a wider systems perspective, the current study examines change and the role that supporting services have on fertilizer application rate change. A total of 238 sugarcane growers completed surveys reporting on changes in fertilizer application along with factors that may explain behavior change. Logistic regressions and negative binomial count-data regressions were used to examine whether farmers had changed fertilizer application rates and if they had, how long ago they made the change, and to explore the impact of individual and system factors in influencing change. Approximately one in three sugarcane growers surveyed (37%) had changed the method they used to calculate fertilizer application rates for the cane land they owned/managed at some point. Logistic regression results indicated growers were less likely to change the basis for their fertilizer calculation if they regarded maintaining good relationships with other local growers as being extremely important, they had another source of off-farm income, and if they had not attended a government-funded fertilizer management workshop in the five years preceding the survey. Similar drivers promoted early adoption of fertilizer practice change; namely, regarding family traditions and heritage as being unimportant, having sole decision-making authority on farming activities and having attended up to 5 workshops in the five years prior to completing the survey. Results demonstrated the influence of government-funded services to support practice change.
ARTICLE | doi:10.20944/preprints202107.0486.v1
Subject: Social Sciences, Accounting Keywords: Economic impact; ornamental horticulture; fruits and nuts; vegetables; flowers; horticulture research; extension
Online: 21 July 2021 (11:14:25 CEST)
This paper summarizes the estimates of the total changes in sales, expenses, and income of participants of the horticulture research and extension programs at the Mississippi State University - Coastal Research and Extension Center for the past five years. Major items outline the estimation procedures for the past five years. The average annual values were used in estimating the total economic impacts of added gross sales, expenses, and incomes of participants in horticulture events. The cumulative total impacts reach $8.7 million in sales, 76 jobs, $1.4 million in labor income, $2.4 million in value-added, and $0.4 million in local, state, and federal taxes. In addition, the total willingness to pay for the horticulture program by the adult participants reached $1.8 million. In comparison, the annual public spending on the horticulture program averaged $1.4 million, creating additional substantial economic impacts to the region.
ARTICLE | doi:10.20944/preprints202002.0238.v1
Subject: Biology, Other Keywords: oxytocin; cellular morphology; neurite outgrowth; neurite retraction; autism; MEF2A; CRISPR-Cas; hyperconnectivity
Online: 17 February 2020 (03:44:01 CET)
The neuropeptide oxytocin (OT) is a well-described modulator of socio-emotional traits, such as anxiety, stress, social behavior, and pair-bonding, however, when dysregulated, it is associated with adverse psychiatric traits, like various aspects of autism spectrum disorder (ASD). In this study, we identify the transcription factor MEF2A as the common link between OT and cellular changes symptomatic for ASD, encompassing neuronal morphology, connectivity, and mitochondrial function. We provide evidence for MEF2A as the decisive factor defining the cellular response to OT: while OT induces neurite retraction in MEF2A expressing neurons, OT causes neurite outgrowth in absence of MEF2A. A CRISPR-Cas-mediated knockout of MEF2A and retransfection of an active version or permanently inactive mutant, respectively, validated our findings. We also identified the phosphatase calcineurin as the main upstream regulator of OT-induced MEF2A signaling. Further, MEF2A signaling dampens mitochondrial functioning in neurons, as MEF2A knockout cells show increased maximal cellular respiration, spare-respiratory capacity, and total cellular ATP. In summary, we reveal a central role for OT-induced MEF2A as major regulator of cellular morphology as well as neuronal connectivity and mitochondrial functioning, with broad implications for a potential treatment of disorders based on morphological alterations or mitochondrial dysfunction.
ARTICLE | doi:10.20944/preprints202008.0539.v1
Subject: Social Sciences, Other Keywords: Correlation; Disease; Extension; Information-Score; Livestock; Perceived-Usefulness
Online: 25 August 2020 (05:01:42 CEST)
Smallholder livestock farmers utilize their existing communication networks as information sources. This study explored these information sources, frequency of contacts and perceived usefulness of information from these sources. Using descriptive and correlation analysis, it categorized respondents according to total information score and explored the relationship between their scores and socio-economic characteristics. Findings show that 65% of farmers in the area scored a high reliance on fellow farmers and extension officials. Mass media sources such as radio and television scored low on perceived usefulness. The correlation coefficients for age (-0.228), farming experience (0.183), extension visits (0.002) and information contacts (0.214) were significant (p<0.05). Level of education (0.256), herd size (0.067) and perceived usefulness of information contacts (0.252) were also significant (p<0.01). Gender, household size, income, cooperative participation and access to financial services were not correlated to the total information scores of respondents. It was recommended that mass media sources in the area be supported by extension communication specialists to disseminate livestock-health related information.
ARTICLE | doi:10.20944/preprints201810.0025.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Key Words: PV-Wind-Hydro Hybrid Power System, Dynamic Modeling, Load Profile, Grid Extension, smart micro grid, fuzzy logic controller, and mat lab/Simulink
Online: 2 October 2018 (14:03:38 CEST)
ABSTRACT Ethiopia is a developing country, where majority of the population lives in rural areas without access to electricity. 83% of the total population of the country use traditional biomass energy as a basic source of energy. In contrast, the country is endowed with sufficient renewable energy resources which can be used as a standalone electric energy supply system for electrifying remote areas of the country. These resources are mainly micro hydropower and wind which can be used individually or the best combination of one another. The application of hybrid renewable energy system has become an important alternative solution for rural electrification program. The Modeling and control of a hybrid PV-Wind-Hydro DG system is also addressed. Dynamic models for the major system components, namely, wind energy conversion system, PV energy conversion system, hydro, inverter, and overall fuzzy logic controller units are developed. Then, a simulation model for the proposed hybrid power system has been developed using MATLAB /Simulink environment. This is done by creating subsystem sets of the major dynamic component models and then assembling into a single aggregate model. The overall power management strategy for coordinating and/or controlling the different energy sources is also presented in the thesis work. Generally there are 800 households with total electric demand of 71.6KW.To satisfy this demand 52%, 35% and 13% is to be contributed from wind/hydro/solar respectively. To use the power economically fuzzy logic controller is used. The controller monitors the demand and the available sources and then switches to the appropriate power supply according to the written rules. Simulations have been carried out to verify the system dynamic performance using a practical load profile and weather data. The result shows that the overall power management strategy is effective and the load demand is balanced. To complete this work, a grid extension from the closest substation has been compared with hybrid system. Cost of the grid extension is estimated based on the data obtained from EEP office. This is done in order to compare the cost of the designed hybrid power system against the cost of grid extension. The result shows that breakeven grid extension distance to be 23.9km which indicates that grid extension is preferable.
ARTICLE | doi:10.20944/preprints202204.0145.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Technology; Adoption; Agriculture; Coffee; Smallholder; Extension; Credit; Market; Access
Online: 15 April 2022 (10:44:57 CEST)
The use of improved agricultural technologies has been reported as the major strategy to increase agricultural production, increased household incomes and addressing poverty. However, adoption of such improved technologies by smallholder coffee farmers has been slow and this has contributed to the low coffee productivity in the country and the poor performance of the coffee sub sector. The study was meant to examine the effect of institutional factors including extension services, access to market and access to credit on technology adoption among smallholder coffee farmers in Kanungu District, Uganda. The study collected both quantitative and qualitative data from 289 smallholder coffee farmers and 8 key informants respectively in major coffee growing sub counties in Kanungu district. The study revealed that access to extension services and access to market have a positive significant influence on agricultural technology adoption while access to market has no significant influence on agricultural technology adoption. The study concluded that there is a positive significant relationship between institutional factors and technology adoption among smallholder coffee farmers in Kanungu district.
Subject: Medicine & Pharmacology, Allergology Keywords: papillary thyroid cancer; obesity; overweight; multifocality; bilaterality; extrathyroidal extension
Online: 28 December 2020 (12:28:18 CET)
Epidemiological studies have shown a strong association between high body mass index (BMI) and papillary thyroid cancer (PTC). We assessed the clinical and histopathological features of PTC in patients with a higher BMI and compared them to analogous parameters in PTC patients with a normal BMI. We retrospectively analyzed 5,021 medical records of patients admitted and surgically treated for thyroid tumors in one center between 2008 and 2018. Finally, we extracted data from 523 adult patients with PTC and stratified patients into two groups according to BMI: Group 1 with BMI < 25 kg/m² and Group 2 with BMI ≥25 kg/m². Data stratification was performed to estimate the association of overweight and obesity with clinical and histopathological features of PTC in both univariate and multivariate binary logistic regression analyses. Overall, compared to patients with a normal BMI, overweight and obese patients had a greater risk of minimal extrathyroidal extension (minimal ETE), multifocality and bilaterality of PTC (p<0.001 for all). Analysis did not show that BMI was significantly associated with more advanced tumor-node-metastasis (TNM) stage (p=0.894). Obesity and overweight were significantly associated with higher aggressiveness of PTC. When considering various management options for PTC patients, these findings regarding overweight and obesity should be taken into consideration during the decision-making process.
REVIEW | doi:10.20944/preprints202008.0294.v1
Subject: Social Sciences, Other Keywords: approaches; extension services; market system; pluralistic; rural development; smallholder
Online: 13 August 2020 (08:07:40 CEST)
Agricultural extension and advisory services in Africa have significant impact on food security as well as economic and social development. Recent moves towards a pluralistic delivery system, including the emergence of private-sector led initiatives in many countries are subject of policy and academic discourse. Our study used an adapted, fit-for-purpose market systems development framework to review available research in extension and advisory services in selected sub-Sahara Africa countries. Using a literature survey methodology, we report evidence of multiple actors in extension delivery, findings that point towards evolution towards mixed delivery as well as objectives. While there are significant uptake of cost-recovery approaches among commercially-oriented farmers, many smallholder farmers still depended on donor-funded services. Our review adds to existing knowledge through incorporating a market systems development framework, which extends the often-used willingness to pay approach, and highlights the need for merger of the public and private-sector objectives to achieve developmental outcomes.
ARTICLE | doi:10.20944/preprints202101.0019.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Renal Cell Carcinoma; Pathological staging; Extrarenal extension; Renal vein invasion
Online: 4 January 2021 (11:31:46 CET)
(1) Background: Overall survival of the patients with renal cell carcinoma (RCC) depends mostly on extra-renal extension, documented by the invasion of the pelvicalyceal system, or the perinephric/renal sinus fat or the renal vein/its segmental intraparenchymal branches. Staging may be challenging because of the high inter-observer variability. We have introduced a more accurate procedure to detect the extra-renal extension and, to possibly evaluate the impact of such more laborious approach, we have compared the RCC pathological staging obtained following both standard and modified procedures; (2) Methods: We selected 54 consecutive cases of RCC diagnosed 18 months before and 54 consecutive cases diagnosed 18 months after the introduction of the new method of sampling. Clinico-pathological characteristics have been statistically analyzed; (3) Results: Most of the features analyzed were non statistically significative, except the extra-renal invasion. More precisely, the occurrence of retrograde venous invasion was higher in the cases grossly approached with the more accurate method; (4) Conclusions: Extra-renal extension to intraparenchymal renal vein branches may be underestimated, leading to an inappropriate under-staging. Using more accurate staging procedures, to disclose the occurrence of intra-renal veins tumoral thrombosis, helps to better define the pathological stage, allowing patients to benefit of better fitting treatments.
ARTICLE | doi:10.20944/preprints201809.0302.v1
Subject: Biology, Ecology Keywords: annual linear extension; calcification; coral reefs; environmental gradients; growth; turbidity
Online: 17 September 2018 (11:13:20 CEST)
Pronounced differences exist in the biodiversity and structure of coral reef assemblages with increasing distance from shore, which may be expected given marked cross-shelf gradients in environmental conditions. Cross-shelf variation in the abundance of coral reef organisms is likely to be caused, at least in part, by differences in demography (e.g., growth and survival), though this has rarely been tested. This study quantified growth of three distinct coral taxa (Acropora nasuta, Pocillopora spp., and Stylophora pistillata) at 6 sites on Australia’s Great Barrier Reef (GBR), encompassing inshore, mid-shelf and outer-shelf reefs. Replicate colonies (up to 15 colonies per species, per reef) were stained using Alizarin red in December 2015 and retrieved 1-year later to quantify linear extension on replicate branches for each colony. Annual linear extension varied within and among coral taxa, with pronounced differences among reefs. For A. nausta. and S. pistillata, growth rates were highest at Orpheus Island, which is an inner shelf reef. However, inter-reef differences in coral growth were not explained by shelf position. Based on differences in skeletal density, which did vary according to shelf position, branching corals at the inshore sites may actually have higher rates of calcification compared to conspecifics on mid- and outer-shelf reefs. This study shows that growth of branching corals is not lower at inshore sites (and perhaps even higher) compared to sites at mid-shelf and outer reefs, despite generally higher levels of sedimentation and turbidity.
ARTICLE | doi:10.20944/preprints202203.0238.v1
Subject: Engineering, Marine Engineering Keywords: Virtual Blade Model; Code extension; CFD modeling; Tidal turbine; Wind turbine
Online: 17 March 2022 (02:37:47 CET)
The Virtual Blade Model (VBM) is the implementation of the Blade element model (BEM). This was done by coupling the Blade Element Momentum theory equations to simulate rotor operation with the Reynolds Averaged Navier-Stokes (RANS) equation to simulate rotor wake and the turbulent flow field around it. Exclusion of actual geometry of blades causes lower computational cost (about 10 to 100 times). Also, due to simplifications in the meshing procedure, VBM is easier to set up than the models that consider the actual geometry of blades. One of the main unaddressed limitations of the VBM code was the constraint of modeling up to ten rotor zones within one computational domain. This paper provides a detailed and well-documented general methodology to develop a virtual blade model for simulation of ten-plus turbines within one computational domain to remove the limitation of this widely used and robust code. It is strongly believed that the technical contribution of this paper, combined with the current sky-rocketing advancement of available computational resources and hardware, would open the gates to simulate various engineering problems in the field of aerospace, clean energy, and many more.
TECHNICAL NOTE | doi:10.20944/preprints202007.0556.v1
Subject: Earth Sciences, Geoinformatics Keywords: Solar radiation; 3D city models; Urban environment; GRASS GIS r.sun; 3D extension
Online: 23 July 2020 (12:20:40 CEST)
Solar3D is an open-source software application designed to interactively calculate solar irradiation at three-dimensional (3D) surfaces in a virtual environment constructed with combinations of 3D city models, digital elevation models (DEMs), digital surface models (DSMs) and feature layers. The GRASS GIS r.sun solar radiation model computes solar irradiation based on two-dimensional (2D) raster maps for given day, latitude, surface and atmospheric conditions. With the increasing availability of 3D city models and demand for solar energy, there is an urgent need for better tools to computes solar radiation directly with 3D city models. Solar3D extends GRASS GIS r.sun from 2D to 3D by feeding the model with input, including surface slope, aspect and time-resolved shading, that is derived directly from the 3D scene using computer graphics techniques. To summarize, Solar3D offers several new features which, as a whole, distinguish itself from existing 3D solar irradiation tools: (1) the ability to consume massive heterogeneous 3D city models, including massive 3D city models such as oblique airborne photogrammetry-based 3D city models (OAP3Ds or integrated meshes); (2) the ability to perform near real-time pointwise calculation for duration from daily to annual; (3) the ability to integrate and interactively explore large-scale heterogeneous geospatial data. (4) the ability to calculate solar irradiation at arbitrary surface positions including at rooftops, facades and the ground. Solar3D is publicly available at https://github.com/jian9695/Solar3D.
ARTICLE | doi:10.20944/preprints201810.0176.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: agricultural stakeholders; extension; multivariate analysis; socio-ecological systems; mental models; sustainable agriculture
Online: 9 October 2018 (06:03:38 CEST)
The sustainability of agriculture depends as much on the natural resources required for production as it does on the stakeholders that manage those resources. It is thus essential to understand the variables that influence the decision-making process of agricultural stakeholders to design educational programs, interventions, and policies geared towards their specific needs, a required step to enhance agricultural sustainability. We examined the perceptions, experiences, and priorities that influence management decisions of five major groups of agricultural stakeholders (conventional small grain producers, organic small grain producers, organic vegetable producers, extension agents and agro-industry crop consultants, and researchers) across the Montana, United States. Results revealed that while stakeholder groups have distinct perceptions, experiences, and priorities, there were similarities across groups. Specifically, organic vegetable and organic small grain producers showed similar responses that were, in turn, divergent of conventional producers, researchers, and crop consultants. Conventional small grain producers and researchers showed overlapping response patterns while crop consultants formed an isolated group. Our results reinforce the need for agricultural education and programs that address unique and shared experiences, priorities, and concerns of multiple stakeholder groups. This study endorses the call for a paradigm shift from the traditional top-down agricultural extension model to one that accounts for participants’ socio-ecological contexts to facilitate the adoption of sustainable agricultural systems that support environmental and human wellbeing.
ARTICLE | doi:10.20944/preprints201809.0147.v1
Subject: Physical Sciences, Astronomy & Astrophysics Keywords: Lorentz invariance; Standard-Model extension; polarization; Active Galactic Nuclei; Gamma-ray Bursts
Online: 9 September 2018 (09:04:03 CEST)
Theories of quantum gravity suggest that Lorentz invariance, the fundamental symmetry of the Theory of Relativity, may be broken at the Planck energy scale. While any deviation from conventional Physics must be minuscule in particular at attainable energies, this hypothesis motivates ever more sensitive tests of Lorentz symmetry. In the photon sector, astrophysical observations, in particular polarization measurements, are a very powerful tool because tiny deviations from Lorentz invariance will accumulate as photons propagate over cosmological distances. The Standard-Model Extension (SME) provides a theoretical framework in the form of an effective field theory that describes low-energy effects due to a more fundamental quantum gravity theory by adding additional terms to the Standard Model Lagrangian. These terms can be ordered by the mass dimension d of the corresponding operator and lead to a wavelength, polarization, and direction dependent phase velocity of light. In this paper, we analyze optical polarization measurements from 63 Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRBs) in order to search for Lorentz violating signals. We derive the first set limits on each of the 10 individual birefringent coefficients of the minimal SME with d = 4, with 95% confidence limits on the order of 10−34 on the dimensionless coefficients.
ARTICLE | doi:10.20944/preprints201807.0576.v1
Subject: Engineering, Mechanical Engineering Keywords: Ball bearing; Fractional Lorenz chaos system; Extension theory; Chua’s Circuit Fault diagnosis
Online: 30 July 2018 (10:00:57 CEST)
In this study we used a non-autonomous Chua’s Circuit, and the fractional Lorenz chaos system together with a detection method from Extension theory to analyze the voltage signals. The measured bearing signals by acceleration sensor were introduced into the master and slave systems through a Chua’s Circuit. In a chaotic system minor differences can cause significant changes that generate dynamic errors, and extension matter-element models can be used to judge the bearing conditions. Extension theory can be used to establish classical and sectional domains using the dynamic errors of the fault conditions. The results obtained were compared with those from Discrete Fourier Transform analysis, Wavelet analysis and an integer order chaos system. The diagnostic ratio showed the fractional order master and slave chaos system calculations. The results show that the method presented in this paper is very suitable for monitoring the operational state of ball bearing system to be superior to the other methods. The diagnosis ratio was better and there were other significant advantages such as low cost and few.
ARTICLE | doi:10.20944/preprints202105.0674.v1
Subject: Engineering, Automotive Engineering Keywords: Offshore wind; life extension; modern portfolio theory; unsupervised machine learning; monopile; risk management
Online: 27 May 2021 (14:01:13 CEST)
The present study aims to develop a risk-based approach to find optimal solutions for life extension management for offshore wind farms based on Markowitz’s modern portfolio theory, adapted from finance. The developed risk-based approach assumes that the offshore wind turbines (OWT) can be considered as cash-producing tangible assets providing positive return from the initial investment (capital) with a given risk attaining the targeted (expected) return. In this regard, the present study performs a techno-economic life extension analysis within the scope of the multi-objective optimisation problem. The first objective is to maximise the return from the overall wind assets, while the latter aims to minimise the risk associated with obtaining the return. In formulating the multi-dimensional optimisation problem, the life-extension assessment considers the results of a detailed structural integrity analysis, free-cash-flow analysis, and probability of project failure, local and global economic constraints. Further, the risk is identified as the variance from the expected mean of return on investment. The risk-return diagram is utilised to classify the OWTs of different classes using an unsupervised machine learning algorithm. The optimal portfolios for the various required rate of return are recommended for different stages of life extension.
ARTICLE | doi:10.20944/preprints202201.0060.v1
Subject: Medicine & Pharmacology, Urology Keywords: extra-prostatic extension; magnetic resonance imaging; radical prostatectomy; nerve-sparing; prostate cancer; staging; diagnostic accuracy
Online: 6 January 2022 (10:05:55 CET)
The accuracy of multi-parametric MRI (mpMRI) in pre-operative staging of prostate cancer (PCa) remains controversial. Objective: To evaluate the ability of mpMRI to accurately predict PCa extra-prostatic extension (EPE) on a side-specific basis using a risk-stratified 5-point Likert scale. This study also aimed to assess the influence of mpMRI scan quality on diagnostic accuracy. Patients and Methods: We included 124 men who underwent robot-assisted RP (RARP) as part of the NeuroSAFE PROOF study at our centre. Three radiologists retrospectively reviewed mpMRI blinded to RP pathology and assigned a Likert score (1-5) for EPE on each side of the prostate. Each scan was also ascribed a Prostate Imaging Quality (PI-QUAL) score for assessing the quality of the mpMRI scan, where 1 represents poorest and 5 represents best diagnostic quality. Outcome measurements and statistical analyses: Diagnostic performance is presented for binary classification of EPE including 95% confidence intervals and area under the receiver operating characteristic curve (AUC). Results: A total of 231 lobes from 121 men (mean age 56.9 years) were evaluated. 39 men (32.2%), or 43 lobes (18.6%) had EPE. Likert score ≥3 had sensitivity (SE), specificity (SP), NPV, PPV of 90.4%, 52.3%, 96%, 29.9%, respectively, and AUC was 0.82 (95% CI: 0.77-0.86). AUC was 0.63 (95% CI: 0.37-0.9), 0.77 (0.71-0.84) and 0.92 (0.88-0.96) for biparametric scans, PI-QUAL 1-3 and PI-QUAL 4-5 scans, respectively. Conclusions: MRI can be used effectively by genitourinary radiologists to rule out EPE and help inform surgical planning for men undergoing RARP. EPE prediction was more reliable when the MRI scan was a) multi-parametric and b) of a higher image quality according to the PI-QUAL scoring system.
ARTICLE | doi:10.20944/preprints202105.0742.v1
Subject: Physical Sciences, Acoustics Keywords: thermal noise decoupling; micro-Newton thrust measurement; torsion balance; ZDVF; PID state extension; fine tree regression
Online: 31 May 2021 (11:11:05 CEST)
The space gravitational wave detection and drag free control requires the micro-thruster to have very low thrust noise within 0.1mHz~100mHz, which poses a great challenge to the ground thrust test. The evaluation and decoupling of thermal noise are the difficulties in the application of torsion balance for most thrusters dissipate heat in the experiment. The research has adopted a calibration scheme of micro-Newton thrust torsion balance. On the basis of Lisa Pathfinder's former research and using ideas inspired from PID control and multi time scale (MTS) for reference, the paper proposes to expand the state space of temperature to be applied on thrust prediction based on fine tree regression (FTR), to subtract the thermal noise filtered by transfer function fitted with z-domain vector fitting (ZDVF). The results show that the thrust amplitude thrust density in diurnal temperature fluctuation is decoupled from 24μN/Hz1/2 to 4.9μN/Hz1/2 at 0.11mHz. And the 1μN square wave modulations of electrostatic fins (ESF) is extracted from the simultaneously ambiguous background of temperature for PTC's heating and cooling. The FTR method is well demonstrated in thermal noise decoupling and can guide the design of thermal control and be extended to other physical quantities for noise decoupling.
Subject: Engineering, Civil Engineering Keywords: life extension; wind turbines; end-of-life issues; probabilistic modelling; economic optimization; fatigue; risk; remaining useful life
Online: 18 January 2021 (15:02:18 CET)
Reassessment of the fatigue life for wind turbines structural components is typically performed using deterministic methods with the same partial safety factors as used for the original design. However, in relation to life extension, the conditions are generally different from the assumptions used for calibration of partial safety factors; and using a deterministic assessment method with these partial safety factors might not lead to optimal decisions. In this paper, the deterministic assessment method is compared to probabilistic and risk-based approaches, and the economic feasibility is assessed for a case wind farm. Using the models also used for calibration of partial safety factors in IEC61400-1 ed. 4 it is found that the probabilistic assessment generally leads to longer additional fatigue life than the deterministic assessment method. The longer duration of the extended life can make life extension feasible in more situations. The risk-based model is applied to include the risk of failure directly in the economic feasibility assessment and it is found that the reliability can be much lower than the target for new turbines, without compromising the economic feasibility.
REVIEW | doi:10.20944/preprints202110.0197.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: AGING; Age-related comorbidities; Angiotensin-Converting Enzyme; Amyloid-degrading enzyme; Alzheimer’s disease; Dementia; Hypertension; Life extension; Stress resistance
Online: 13 October 2021 (11:04:43 CEST)
A recent report from the American Heart Association in 2018 shows that over 103 million American adults have hypertension. The angiotensin-converting enzyme (ACE) (EC 18.104.22.168) is a dipeptidyl carboxylase that, when inhibited, can reduce blood pressure through the renin-angiotensin system. ACE inhibitors are used as a first-line medication to be prescribed to treat hypertension, chronic kidney disease, heart failure among others. It has been suggested that ACE inhibitors can reduce the symptoms in mouse models. Despite the benefits of ACE inhibitors, previous studies also have suggested that alterations in the ACE gene are risk factors for Alzheimer’s disease (AD) and other neurological diseases. In mice, overexpression of ACE in the brain reduces symptoms of the AD-model systems. Thus, we find opposing effects of ACE on health. To clarify the effects, we dissect the functions of ACE as follows: (1) angiotensin-converting enzyme that hydrolyzes angiotensin I to make angiotensin II in the renin-angiotensin system; (2) amyloid-degrading enzyme that can hydrolyze beta-amyloid and reduce amyloid toxicity. The efficacy of the ACE inhibitors is well established in humans, while the knowledge specific to AD remains to be open for further research. We provide an overview of ACE and inhibitors that link a wide variety of age-related comorbidities from hypertension to Alzheimer’s disease to aging. ACE also serves as an example of the middle-life crisis theory that assumes deleterious events during the midlife, leading to age-related later events.
REVIEW | doi:10.20944/preprints201811.0179.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: calorie restriction mimetics; anti-aging; lifespan extension; glucose metabolism modulation; chitosan; acarbose; SGLT2 inhibitor; 2-deoxy-D-glucose; D-allulose; D-glucosamine
Online: 7 November 2018 (15:26:42 CET)
Calorie restriction (CR) has been shown to prolong the lifespan of humans, but enforcing long-term CR is difficult. Therefore, a compound that reproduces the effect of CR without CR is needed. In this review, we summarize the current knowledge on compounds with CR mimetic (CRM) effects. More than 10 compounds have been listed as CRMs, some of which are conventionally categorized as upstream-type CRMs showing glycolytic inhibition while the others are categorized as downstream-type CRMs that regulate or genetically modulate intracellular signaling proteins. Among these, we focus on upstream-type CRMs and propose their classification as compounds with energy metabolism inhibition effects, particularly glucose metabolism modulation effects. The upstream-type CRMs reviewed include chitosan, acarbose, sodium-glucose cotransporter 2 inhibitors, and hexose analogs such as 2-deoxy-D-glucose, D-glucosamine, and D-allulose, which show anti-aging and longevity effects. Finally, we discuss the molecular definition of upstream-type CRMs.