Simplified Strategies Research Articles

Multi-constraints based predictive current control of simplified neutral point clamped inverter

PurposeMaintaining a balanced neutral point, reducing power loss, execution time are important criteria for the controlling of neutral point clamped (NPC) inverter. However, it is tough to meet all the challenges and also supplying the load current within the harmonic limit. This paper aims to maintain load current quality within the Institute of Electrical and Electronics Engineers 519 standard and meet the above-mentioned challenges.Design/methodology/approachThe output load current of a three-level simplified neutral point clamped (3 L-SNPC) inverter is controlled in this paper using model predictive control (MPC). The 3 L-SNPC inverters is considered because fewer semiconductor devices are used in this topology; this will enhance the reliability of the system. MPC is used as a controller because it can handle the direct current-link capacitors’ voltage balancing problem in a very intuitive way. The proposed 3 L-SNPC yields similar current total harmonic distortion (THD), transient and steady-state responses, voltage stress and over current protection capability as the conventional NPC inverter. To reduce the computational burden of the proposed SNPC system, two simplified MPC strategies are proposed, namely, single voltage vector prediction-based MPC and selective voltage vector prediction-based MPC.FindingsThe system shows a current THD of 2.33% at 8.96 kHz. The overall loss of the system is reduced significantly to be useful in medium power applications. The required execution times for the simplified MPC strategies are tested on the hardware dSPACE 1104 platform. It is found that the single voltage vector prediction-based MPC and the selective voltage vector prediction-based MPC are computationally efficient by 8.28% and 62.9%, respectively, in comparison with the conventional MPC-based conventional NPC system.Originality/valueMultiple system constraints are considered throughout the paper and also compare the SNPC to the conventional NPC inverter. Proper current tracking, over-current protection, overall power loss reduction especially switching loss and maintaining capacitor voltages balance at a neutral point are achieved. The improvement of execution time has also been verified and calculated using hardware-in-loop of the dSPACE DS1104 platform.

Study on simplified strategies for procedure of rapid detection of water toxicity

In this work, a simplified procedure of detection of water toxicity based on Pt ultramicroelectrode (UME) and mixed microorganism cultured without sterilization was the first proposed. A stable Pt UME was successfully prepared with a special glass tube as insulation and support material, which was used as working electrode in the biosensor. The Pt UME exhibits the typical cyclic voltammogram (CV) of Pt UME with sigmoid shape and possesses good stability, enlarged current response and tunable dimension. In addition, it was an effective and simple method for toxicity biosensor using mixed microorganisms cultured in unsterilized lysogeny broth (LB) as the bioreceptor. K3[Fe(CN)6] was used as an electron mediator. Under the optimal conditions of 30 mM K3[Fe(CN)6], OD600 = 1 cell concentration, and 50 mM phosphate-buffered solution (PBS), the half-maximal inhibitory concentration (IC50) values measured for Cd2+, Cu2+ and Ni2+ were 3.99 mg/L, 1.16 mg/L and 2.37 mg/L, respectively. The results indicated that the biosensor with large diameter Pt UME and mixed microorganisms cultured in unsterilized LB realized rapid and simple detection of water toxicity.

Overlap Between Sagebrush Habitat Specialists Differs Among Seasons: Implications for Umbrella Species Conservation

Conservation strategies that rely on umbrella species depend on spatial overlap with target species of concern, yet the temporal and spatial scale at which co-occurrence is assessed is rarely considered. In seasonal environments, shifts in space use across seasons could alter patterns of co-occurrence, especially at regional and local scales that are relevant to land management. Greater sage-grouse (Centrocercus urophasianus), which currently serve as an umbrella species for sagebrush ecosystems across the western United States, move between seasonal habitats. Our goal was to evaluate the degree to which sage-grouse general and seasonal habitats overlap with habitat for another sagebrush-dependent species of conservation concern, the pygmy rabbit (Brachylagus idahoensis). We created inductive species distribution models for both species in east-central Idaho. We used maximum entropy methods to build models incorporating environmental factors representing topography, vegetation, climate, and soil characteristics. Despite both species being sagebrush obligates, we documented a relatively modest degree of spatial overlap between these species across the region; only 49% of highly suitable habitat for pygmy rabbits overlapped with areas mapped as highly suitable for sage-grouse when considering general habitat, and overlap was lower (18−31%) when we evaluated seasonal sage-grouse distributions. Our models predicted that pygmy rabbits would also occur in narrow (1−2 km) sagebrush corridors between steep terrain features where sage-grouse are typically absent. This work suggests that additional habitat conservation for pygmy rabbits will be needed to support their long-term persistence, especially where their habitat falls outside of areas designated as primary habitat for sage-grouse. Our models provide useful information for land management and habitat restoration within the study region and also offer a cautionary tale for application of simplified conservation strategies like the designation of umbrella species. Incorporating spatial and temporal scales into assessments of co-occurrence may increase effectiveness of conservation strategies involving surrogate species.

A Macro-Distinct Element Model (M-DEM) for out-of-plane analysis of unreinforced masonry structures

Despite the vulnerability of unreinforced masonry (URM) structures to out-of-plane (OOP) loading, computational methods that can efficiently simulate OOP failure at the building scale are still limited. Current methods typically rely on simplified static analysis approaches or refined micro-modeling techniques that entail high computational expense, thus limiting their employment to reduced-scale and local problems. With a view to overcome these issues, a novel Finite-Distinct macroelement model which combines the efficiency of simplified modeling strategies with the multifaceted capabilities of discontinuum-based methods, is developed and implemented in the framework of the Distinct Element Method (DEM). Shear and flexural failure modes, either in-plane or out-of-plane, are accounted for by zero-thickness interface spring layers, whose layout is determined a priori as a function of the considered masonry bond pattern. Meanwhile, crushing failure is modeled through homogenized Finite Element macro-blocks. The proposed discretization scheme is conceived so that the model can also be used to simulate in-plane damage, for which the model has already been validated. Simplified expressions are proposed for determining equivalent mechanical properties of the interface spring layers, depending on their inclination. Similarly, analytically-based equations are used to significantly reduce the number of springs needed to adequately reproduce the OOP bending response at the joint level. Numerical simulations are compared to previous experimental quasi-static and dynamic tests on both brick and block URM components, characterized by markedly different vertical pressures, aspect ratios, boundary conditions and confinement; both one-way and two-way bending actions are considered. The results indicate that the model can satisfactorily reproduce the measured load–displacement curves in a reasonable timeframe, as well as the experimentally-observed failure mechanisms.

Real-world Antihypertensive Treatment Patterns, Treatment Adherence, and Blood Pressure Control in the Elderly: An Italian Awareness-raising Campaign on Hypertension by Senior Italia FederAnziani, the Italian Society of Hypertension and the Italian Federation of General Practitioners.

IntroductionAchieving hypertension control is beneficial regardless of age. Fixed-combination pills have the potential of increasing adherence to treatment, improving the benefit/risk ratio, and simplifying therapy, with resulting convenience especially in the elderly.AimWe examined real-world antihypertensive treatment adherence and hypertension control rates in a cohort of Italian elderly individuals, enrolled in a prospective, pragmatic awareness-raising campaign on blood pressure (BP).Methods13196 treated hypertensive elderly (mean age 73.2±7.5 years, 55.5% women) were recruited through opportunistic sampling, answered a brief questionnaire on antihypertensive therapy, and were followed-up for 6 months, when BP was measured as per routine care. Controlled hypertension was defined as BP < 140/90 mmHg. Real-world treatment adherence and hypertension control rates were evaluated at 6 months according to different treatment patterns (fixed-dose versus free combinations), using Yates correction for continuity to assess likelihood estimates for differences between treatments.Results10551 participants (80%) were on a single-pill therapy and 3445 were on a fixed combination therapy of two (24.8%) or three (1.3%) drugs. Individuals on a fixed combination therapy were more adherent to treatment than the counterparts (p < 0.001). Full adherence increased with the number of drugs/pill among single-pill users (47.5%, 68.5%, and 100% with 1, 2, or 3 drugs/pill; p < 0.001). Hypertension control rates were 70% and 65.2% (p = 0.001) according to fixed or free combinations of two drugs and 71% and 63.9% (p = 0.321) for fixed or free combinations of three drugs.ConclusionsReal-world data suggest that simplified treatment strategies and use of fixed combinations improve adherence to antihypertensive therapy and BP control in the elderly.

A Review of the Performance of Infilled RC Structures in Recent Earthquakes

The primary objective is to present the most representative types of damage observed in reinforced concrete (RC) structures due to earthquakes. Those damages are divided according to the ten most representative types. Examples and the main reasons that could trigger each failure mechanism are presented. The definition of these damage types is supported by post-earthquake damage reconnaissance missions in Sichuan (China) in 2008, L’Aquila (Italy) in 2009, Lorca (Spain) in 2011, Emilia-Romagna (Italy) in 2012, Gorkha (Nepal) in 2015, Muisne (Ecuador) in 2016 and Chiapas (Mexico) in 2017. An extensive discussion is presented concerning the infill walls’ seismic behaviour and their interaction with the RC structural elements. The presentation of the significant learnings and findings concerning the typical damage herein presented and discussed are compared with the common Southern European construction practice. The impact of the infill walls on the rehabilitation costs of damaged RC buildings is also studied. These costs are compared to those related to the structural damage and rehabilitation of the entire building structure to understand the impact of the infill walls. Finally, a case study is presented to study the effect of implementing simplified retrofitting strategies to prevent the soft-storey mechanism, one of the most common problems observed in past earthquake events.

A simplified non-linear numerical method for the assessment of welding induced deformations

Welding numerical simulation has always been a formidable challenge because of the involved complex phenomena to be modelled. The task is increasingly challenging when multi-runs welding or welding of ships is needed to be modelled. In these cases, the computational effort is so high that solving the problem via computational welding mechanics is impossible so far. Alternatively, different simplified numerical strategies were developed to overcome this issue such as those based on the inherent strain. Unfortunately, such numerical models are rarely able to capture the effects induced by a variation of the welding sequence or clamping conditions since they are solved in the elastic filed; most of them are therefore not useful to the design optimization of a welded assembly. In this scenario, a new approach is proposed to quantify the welding induced deformations that uses virtual elements to model the weld bead in the elastic-plastic filed and auxiliary elements to apply equivalent loads determined by experiments on a single welded joint. A specific inverse analysis algorithm has been developed to use the method. The model was applied to a real welded assembly in which both the welding sequence and clamping condition were varied. In addition, for the numerical validation, a novel registration algorithm has been developed to move from solid geometries to middle plane representations. Numerical results were found in good agreement with those obtained by experiments even when the welding sequence and clamping conditions are changed.

Scoping review of trials evaluating adhesive strategies in pediatric dentistry: where do simplified strategies lie?

BackgroundAdhesive restorations allow a conservative approach to caries management and are increasingly used as a restorative option in pediatric dentistry. Placement can be difficult in children because of the cooperation required for multiple bonding steps. Due to this, it is vital to assess if novel, simpler strategies have been featured in clinical trials and if clinical trials are researching the different existing adhesive strategies.MethodsThis review followed Preferred Reporting Items for Systematic Reviews and Meta-analysis adapted for Scoping Reviews (PRISMA-ScR) guidelines. PubMed/Medline, Cochrane Central, Scopus and EMBASE were used for systematic search, using free keywords and controlled search terms. Clinical trials of children requiring a restorative intervention which featured adhesive strategies were included. Only peer-reviewed trials of primary teeth restored with resin composites, published in the last 10-year period were eligible. Data charting was accomplished independently by two reviewers, and studies were summarized according to their date, type, intervention, sample size, observation period, outcomes and conclusions. Quality assessment was performed using Cochrane’s Risk of Bias 2.0 tool.Results700 potentially relevant references were found, which after a rigorous inclusion scheme, resulted in a total of 8 eligible clinical trials. Out of these, 7 were randomized clinical trials. Most trials featured a split-mouth design and the observation period ranged from 12 to 36 months. The trials evaluated interventions of two self-adhesive composites, two bulk-fill composites, two novel composites, one compomer and eight adhesives from different strategies. Most studies (4/8) included were judged to raise some concerns regarding risk of bias, while two were classified as high risk and two as low.ConclusionFew studies comparing adhesive strategies were found, especially adhesives in sound substrates. The existing studies do not reflect all current approaches that could be used in pediatric dentistry. Further studies addressing bioactive composites and contemporary adhesives are necessary.

Synthesis of Hydrophilic Phosphorus Ligands and Their Application in Aqueous-Phase Metal-Catalyzed Reactions.

Transition metal‐catalyzed reactions in aqueous media are experiencing a constant increase in interest. In homogenous catalysis the use of water as a solvent offers advantages in cost, safety, the possibility of two‐phase catalysis and simplified separation strategies. In the life sciences, transition metal catalysis in aqueous systems enables the ligation or modification of biopolymers in buffer systems or even in their cellular environment. In biocatalysis, aqueous systems allow the simultaneous use of enzymes and transition metal catalysts in cascade reactions. The use of water‐soluble phosphine ligands still represents the most reliable and popular strategy for transferring metal catalysts into the aqueous phase. This review summarizes the recent advancements in this field since 2009 and describes current synthetic strategies for the preparation of hydrophilic phosphines and phosphites. In addition, recent applications of transition metal catalysis in aqueous solvents using these hydrophilic ligands are presented.

Medication Management Among Older Adults With Multiple Chronic Conditions: What Role Do Caregivers Play?

Many older adults manage multiple chronic conditions (MCC) that require adherence to complex medication regimens. Few studies have investigated the degree to which caregivers support medication-related behaviors. We conducted semi-structured qualitative interviews with 25 caregivers of older adults with MCC to characterize caregiver medication assistance. Two coders used content and constant comparative analysis to analyze transcripts. The mean age of caregivers was 61 years; the majority were female (68%) and identified as non-white (Black, 52%; Hispanic, 8%). Caregivers were predominantly spouses (n=10), or children (n=11). Older adults were on average 73 years old, managing 5 chronic conditions and prescribed 7 medications. Caregivers acknowledged the importance of medications to the older adult’s health, but their involvement in daily medication management was limited. Some caregivers preferred that the older adult continue these tasks to maintain autonomy, especially when caring for older adults who valued maintaining independence. Caregivers assumed medication responsibilities after older adults experienced sudden changes in health or upon observing non-adherence (e.g. full pill bottles). Older adults with higher medication burden (12+ medicines) adopted inefficient, cumbersome medication management practices; caregivers suggested simplified strategies, but the older adults refused to adopt recommended strategies. To combat resistance from the older adult, caregivers disguised assistance and deployed workaround strategies to monitor medication-taking behaviors. These findings suggest older adults and caregivers share a value of promoting independence of medication management, up until safety is seriously questioned. Additionally, there is a breakdown in communication at the time when older adults may benefit from increased caregiver involvement.

Control strategies for switchable roof insulation systems applied to US residential homes

This paper summarizes the main findings for evaluating the effectiveness of simplified and advanced control strategies to operate switchable insulation systems applied to the attic of US residential buildings. Specifically, the evaluation analysis is performed for five US representative climates to determine the performance of several control options for dynamic insulation systems to minimize the heating and cooling energy end-uses for US homes. The control strategies considered include scheduled settings, temperature-based rule sets, and optimal control schemes. The comparative analysis results clearly indicate that the switchable insulation systems even when only applied to attics have significant potentials in reducing the cooling energy use of US residential homes especially those located in mild climates. Even when operated with simplified controls such as time-scheduled controls and temperature-based rule-sets, dynamic insulations are capable of providing substantial energy savings. In particular, controls using rules based on mean air and sol-air temperatures result in cooling energy savings ranging from 8% to 43% for all US climates. When optimal controls are used to operate attic dynamic insulation systems, up to 40% additional savings in cooling energy can be achieved compared to the best simplified controls at least when the building is located in Golden, CO.

Design and control aspect of segmented proportional integral‐repetitive controller parameter optimization of the three‐phase boost power factor correction rectifier

SummaryThis paper presented a modeling and control aspect with an offline‐based parameter optimization algorithm for effectively tuning the controller parameters of the three‐phase boost power factor correction (PFC) rectifier system. While analyzing the shortcomings of the traditional PI control with complex control transfer functions from small‐signal models and investigating the limitations of PI control on harmonic suppression from the internal model principle, a simplified form of control transfer functions based on the small‐signal model has been proposed with segmented control action. Consequently, the methodology has the advantages of both simplified control strategies and segmented PI‐repetitive control so as to achieve the performance of high‐power factor and to reduce total harmonic distortion in a broad range of load conditions. However, the segmented PI‐repetitive control contains many control parameters. Thus, the solution and optimization for tuning the controller parameters based on heuristic offline optimization technique have been used to speed up the design of control system parameters. The validity and feasibility of the proposed design and optimization are verified using a 5‐kW three‐phase PFC rectifier with digital signal processor (DSP) TMS320F28335 prototype hardware. The results were then compared with those of traditional controller designs, which show the improvements and effectiveness of rectifier performance after adopting the proposed design and optimization technique.

Utility of TRBC1 Expression in the Diagnosis of Peripheral Blood Involvement by Cutaneous T-Cell Lymphoma

Peripheral blood involvement by cutaneous T-cell lymphoma is typically assessed by flow cytometry and plays a critical role in diagnosis, classification, and prognosis. Simplified strategies to detect tumor cells (Sezary cells) fail to exclude reactive subsets, whereas tumor-specific abnormalities are subtle and inconsistently present. We implemented a flow cytometric strategy to detect clonal Sezary cells based on the monotypic expression of one of two mutually exclusive TCR constant β chains, TRBC1 and TRBC2. Analysis of CD4+ T-cell subsets and TCR variable β classes from healthy donors showed polytypic TRBC1 staining. Clonal Sezary cells were identified by TRBC1 staining in 56 of 111 (50%) samples from patients with cutaneous T-cell lymphoma, accounting for 7-18,155 cells/μl and including 13 cases (23%) lacking tumor-specific immunophenotypic abnormalities. CD4+ T-cell subsets from 86 patients without T-cell lymphoma showed polytypic TRBC1 staining, except for five patients (6%) with minute T-cell clones of uncertain significance accounting for 53-136 cells/μl. Assessment of TRBC1 expression within a comprehensive single-tube flow cytometry assay effectively overcomes interpretative uncertainties in the identification of Sezary cells without the need for a separate T-cell clonality assay.

The heuristics that guide healthiness perception of ultra-processed foods: a qualitative exploration.

To explore the conceptualisation of healthy food by citizens and how they judge the healthiness of ultra-processed foods. Four focus groups were conducted using a semi-structured discussion guide. Focus group discussions were held about the concept of healthy food, what characterise a healthy product and healthiness perception of ultra-processed products. Transcripts of the focus groups were analysed following an inductive coding approach. Uruguay, one of the Latin American countries with the highest prevalence of overweight and obesity. Fifty-two adult Uruguayan participants, diverse in terms of gender, age, educational level and socio-economic status. In agreement with previous studies on lay perceptions of healthy eating, the conceptualisation of healthy food was mainly focused on food characteristics. Although participants regarded lack of processing as a cue for healthiness, they did not categorise all ultra-processed products as unhealthy. Albeit some product categories were automatically regarded as unhealthy, participants considered that other categories could include healthy and unhealthy products. In such cases, they explicitly referred to several simplified cognitive strategies to judge whether an ultra-processed product is healthy or not. Results showed that participants tended to rely on simple cues, such as label design, nutrient claims, brand, price and country of origin as indicators of product healthiness. Healthiness perception of ultra-processed products seems to be largely influenced by heuristics, which stresses the need to implement policies that make the potential negative effects of ultra-processed products salient.

The Roof Bracing as Minimum Intervention for the Reduction of the Seismic Vulnerability of Historical Industrial Buildings: Analytical and Numerical Simplified Strategies for the Assessment of the Performances

ABSTRACT The paper deals with the reduction of the seismic vulnerability of historical masonry buildings characterized by a wide room, of significant height, provided by a multi-sloping timber roof lying on perimeter walls and, internally, on columns or pillars (e.g. industrial buildings). Typically, these structures are extremely vulnerable to earthquakes but a minimum intervention, consisting in the bracing of the timber roof through wooden-based sheathing panels, can improve the seismic performances providing an adequate restraint against the walls overturning and fostering the box-behaviour of the entire structure. The case study of an ancient industrial building is analyzed. A smart analytical design strategy for the dimensioning of the bracings and the evaluation of the resisting ground acceleration is developed. A simplified numerical modelling strategy for pushover analysis, based on the equivalent frame method for the masonry walls and on equivalent diagonal springs for the roof bracings, is also presented.

Evaluation of the Aptima HCV Quant Dx Assay for Hepatitis C Virus RNA Detection from Fingerstick Capillary Dried Blood Spot and Venepuncture-Collected Samples.

Simplified diagnostic strategies are needed increase hepatitis C virus (HCV) testing to determine active infection and link people into treatment. Collection methods such as dried blood spots (DBS) have advantages over standard phlebotomy, especially within marginalized populations. We evaluated the diagnostic performance of the Aptima HCV Quant assay for the quantification and detection of HCV RNA from paired DBS and venepuncture samples. Specimens were collected from participants enrolled in an Australian observational study. We compared HCV RNA detection from DBS against venepuncture samples (gold standard). One hundred sixty-four participants had paired samples and HCV RNA was detected in 45 (27% [95% confidence interval, 21%-35%]) by the Aptima assay in venepuncture samples. Sensitivity of the Aptima assay for HCV RNA quantification from DBS (≥10 IU/mL in plasma) was 100% and specificity was 100%. Sensitivity for HCV RNA detection from DBS was 95.6% and specificity was 94.1%. A small bias in plasma over DBS was observed with good agreement (R2 = 0.96). The Aptima HCV Quant assay detects active infection from DBS samples with acceptable diagnostic performance and is clinically comparable to plasma. These data will strengthen the case for the registration of a DBS kit insert claim, enabling future clinical utility.

How Choice Complexity in Liberalized Markets Hurts the Demand for Green Electricity

Many countries have liberalized their residential electricity markets or are considering to do so. Liberalization provides consumers with more freedom of choice but also leads to higher choice complexity as consumers face a much larger number of different electricity contracts to choose from. We hypothesize that consumers react to this increased choice complexity in liberalized markets by applying simplified decision strategies that allow them to reduce cognitive effort. In particular, we predict that with increasing size of choice sets, consumers focus more on simple price attributes of electricity contracts and less on the relatively complex environmental attributes, leading to a decrease in the demand for green electricity. In two online experiments conducted in a representative (n=610) and a student sample (n=1,212) in Switzerland, we find that indeed when faced with a larger choice set participants focus more on prices and choose cheaper electricity contracts containing less renewable and more conventional energy than when faced with a smaller choice set. In addition, we also find evidence that a tax on conventional energy is a more effective policy instrument for shifting demand towards renewables than behavioral instruments in the form of social norm interventions. Our results suggest that a liberalization of the household electricity market has to be carefully managed such that consumers are not overwhelmed and do not shift their demand to cheaper but less environmentally-friendly energy sources.

Analysis of the Influence of Diesel Spray Injection on the Ignition and Soot Formation in Multiple Injection Strategy

Multiple injection strategies have increased their capabilities along with the evolution of injection system technologies up to the point that nowadays it is possible to inject eight different pulses, permitting to improve the engine performance, and consequently, emissions. The present work was realized for two simplified strategies: a pilot-main and a main-post, in order to analyze the influence of an auxiliary pulse on the main and otherwise, in reactive conditions for two pilot/post quantities and four hydraulic dwell times. The study was carried out by employing two optical techniques: diffused back-illumination with flame bandpass chemiluminescence for measuring soot, represented by soot-maps distribution, and single-pass schlieren for ignition delay (ID). Furthermore, a novel methodology for decoupling the start of combustion (SOC) of the second pulse was developed and successfully validated. From the ignition delay results, it was found for all test points that the pilot injection enhanced conditions, which promote a faster ignition of the main pulse, also at higher chamber temperatures, all conditions presented a separate combustion event for each injection. In emission terms, soot increased in the pilot-main strategies compared to its single injection case, as well as, in conditions that promote faster-premixed combustion.

Evaluation of the Xpert HCV VL Fingerstick point-of-care assay and dried blood spot HCV-RNA testing as simplified diagnostic strategies among people who inject drugs in Catalonia, Spain

BackgroundCatalonia requires decentralized and simplified strategies for the diagnosis of viremic HCV infection among people who inject drugs (PWID). We aimed to perform a direct comparison of the diagnostic performance between two, single-step strategies for the screening and diagnosis of viremic HCV infection in PWID attending a drug consumption room (DCR) in Barcelona: i) on-site HCV-RNA testing using the point-of-care test (PoCT) Xpert HCV VL Fingerstick; and ii) on-site dried blood spots (DBS) collection for HCV-RNA testing at the laboratory (in-house assay). Additionally, we aimed to assess participants’ preferences in receiving HCV-RNA testing results and feasibility of same-day delivery of PoCT results. MethodsThe real-world, clinical performance of these two strategies was established in comparison with the reference method (HCV viral load testing with the Xpert HCV Viral Load assay at the laboratory from venous plasma collected at the DCR). HCV genotypes/subtypes and HIV status were also determined by sequencing and serology, respectively. A questionnaire including preferences regarding the delivery of test results was administered. ResultsThe prevalence of HCV-RNA was 63.0% (of which 25.8% were co-infected with HIV). The RNA-PoCT showed a sensitivity of 98.4% for detectable viral loads (>4 IU/mL) and of 100% for quantifiable viral loads (≥10, ≥1000 and ≥3000 IU/mL). For the DBS-based assay, a sensitivity of 93.7% was obtained for detectable viral loads, 96.7% for the quantifiable ≥10 IU/mL threshold, and 98.3% for both the quantifiable ≥1000 and ≥3000 IU/mL thresholds. No significant differences were detected between the sensitivity values of these two strategies, and the specificity was 100% in both cases. Half of the participants preferred to receive the HCV-RNA result on the same day, and 80% of participants received their RNA-PoCT results on the same day. ConclusionsBoth the HCV-RNA PoCT and the DBS-based assay are highly reliable tools for the simplified diagnosis of viremic HCV infection among current PWID. These strategies allow for on-site sample collection and delivery of test results, facilitating decentralized care in harm reduction services.

Transient compensation for thermistor-based sensors in constant temperature configuration

This paper proposes a transient compensation method for thermistor-based sensors in constant temperature configuration. The main objective is to use a filtered estimation of the neglected transient effect in order to avoid steady-state assumption and to mitigate the transitory measurement error. A direct compensation method is proposed to obtain the compensated measurement from the original uncompensated information based on the electric equivalence principle. Digital and analog simplified estimation strategies are considered to obtain the filtered derivative of the thermistor temperature. A frequency response analysis is presented to derive the relationship between transient estimation errors and sampling interval. Finally, an experimental case study is presented to: (i) illustrate the effectiveness of the compensation method, (ii) analyze measurement noise effect in the context of the proposed approach and (iii) discuss about the advantages of the gain correction in the context of the proposed approach.