Simultaneous Sampling Research Articles

Variance reduction via simultaneous importance sampling and control variates techniques using vegas

Monte Carlo (MC) integration is an important calculational technique in the physical sciences. Practical considerations require that the calculations are performed as accurately as possible for a given set of computational resources. To improve the accuracy of MC integration, a number of useful variance reduction algorithms have been developed, including importance sampling and control variates. In this work, we demonstrate how these two methods can be applied simultaneously, thus combining their benefits. We provide a python wrapper, named CoVVVR, which implements our approach in the VEGAS program. The improvements are quantified with several benchmark examples from the literature.

Comparative analysis of hemoglobin, potassium, sodium, and glucose in arterial blood gas and venous blood of patients with COPD

The study aims to assess the accuracy of the arterial blood gas (ABG) analysis in measuring hemoglobin, potassium, sodium, and glucose concentrations in comparison to standard venous blood analysis among patients diagnosed with chronic obstructive pulmonary disease (COPD). From January to March 2023, results of ABG analysis and simultaneous venous blood sampling among patients with COPD were retrospectively compared, without any intervention being applied between the two methods. The differences in hemoglobin, potassium, sodium, and glucose concentrations were assessed using a statistical software program (R software). There were significant differences in the mean concentrations of hemoglobin (p < 0.001), potassium (p < 0.001), and sodium (p = 0.001) between the results from ABG and standard venous blood analysis. However, the magnitude of the difference was within the total error allowance (TEa) of the United States of Clinical Laboratory Improvement Amendments (US-CLIA). As for the innovatively studied glucose concentrations, a statistically significant difference between the results obtained from ABG (7.8 ± 3.00) mmol·L−1 and venous blood (6.72 ± 2.44) mmol·L−1 was noted (p < 0.001), with the difference exceeding the TEa of US-CLIA. A linear relationship between venous blood glucose and ABG was obtained: venous blood glucose (mmol·L−1) = − 0.487 + 0.923 × ABG glucose (mmol·L−1), with R2 of 0.882. The hemoglobin, potassium, and sodium concentrations in ABG were reliable for guiding treatment in managing COPD emergencies. However, the ABG analysis of glucose was significantly higher as compared to venous blood glucose, and there was a positive correlation between the two methods. Thus, a linear regression equation in this study combined with ABG analysis could be helpful in quickly estimating venous blood glucose during COPD emergency treatment before the standard venous blood glucose was available from the medical laboratory.

Characteristics of pulmonary artery strain assessed by cardiovascular magnetic resonance imaging and associations with metabolomic pathways in human ageing.

Pulmonary artery (PA) strain is associated with structural and functional alterations of the vessel and is an independent predictor of cardiovascular events. The relationship of PA strain to metabolomics in participants without cardiovascular disease is unknown. In the current study, community-based older adults, without known cardiovascular disease, underwent simultaneous cine cardiovascular magnetic resonance (CMR) imaging, clinical examination, and serum sampling. PA global longitudinal strain (GLS) analysis was performed by tracking the change in distance from the PA bifurcation to the pulmonary annular centroid, using standard cine CMR images. Circulating metabolites were measured by cross-sectional targeted metabolomics analysis. Among n = 170 adults (mean age 71 ± 6.3 years old; 79 women), mean values of PA GLS were 16.2 ± 4.4%. PA GLS was significantly associated with age (β = -0.13, P = 0.017), heart rate (β = -0.08, P = 0.001), dyslipidemia (β = -2.37, P = 0.005), and cardiovascular risk factors (β = -2.49, P = 0.001). Alanine (β = -0.007, P = 0.01) and proline (β = -0.0009, P = 0.042) were significantly associated with PA GLS after adjustment for clinical risk factors. Medium and long-chain acylcarnitines were significantly associated with PA GLS (C12, P = 0.027; C12-OH/C10-DC, P = 0.018; C14:2, P = 0.036; C14:1, P = 0.006; C14, P = 0.006; C14-OH/C12-DC, P = 0.027; C16:3, P = 0.019; C16:2, P = 0.006; C16:1, P = 0.001; C16:2-OH, P = 0.016; C16:1-OH/C14:1-DC, P = 0.028; C18:1-OH/C16:1-DC, P = 0.032). By conventional CMR, PA GLS was associated with aging and vascular risk factors among a contemporary cohort of older adults. Metabolic pathways involved in PA stiffness may include gluconeogenesis, collagen synthesis, and fatty acid oxidation.

Synchronized measurement method for urban distribution networks based on proportional-integral control

In the context of the rising prevalence of renewable energy, the need for precise and synchronized measurements in urban distribution networks has become increasingly critical. Conventional synchronization techniques, which predominantly depend on Global Navigation Satellite System (GNSS) timing signals, are often plagued by significant sampling time errors. Addressing this challenge, this study introduces an innovative automatic synchronization measurement method employing proportional-integral (PI) control. This method is composed of three integral components: the monitoring of local clock phases via pulses per second (PPS) signals, modulation of the clock phase through a PI controller, and the estimation of grid phasors from the synchronized sampled data. The test results of this method on a hardware platform demonstrate its capability to significantly reduce the sampling error from 2 × 10−3 V to an impressive 1 × 10−5 V, while also meeting the requirements of the synchronized phasor measurement standards outlined in C37.118.1. These advancements underscore the significant potential of PI-controlled simultaneous sampling in enhancing the operational efficiency and reliability of urban distribution networks, particularly in environments with a high integration of renewable energy sources.

Exceptionally low mercury concentrations and fluxes from the 2021 and 2022 eruptions of Fagradalsfjall volcano, Iceland

Mercury (Hg) is naturally released by volcanoes and geothermal systems, but the global flux from these natural sources is highly uncertain due to a lack of direct measurements and uncertainties with upscaling Hg/SO2 mass ratios to estimate Hg fluxes. The 2021 and 2022 eruptions of Fagradalsfjall volcano, southwest Iceland, provided an opportunity to measure Hg concentrations and fluxes from a hotspot/rift system using modern analytical techniques. We measured gaseous Hg and SO2 concentrations in the volcanic plume by near-source drone-based sampling and simultaneous downwind ground-based sampling. Mean Hg/SO2 was an order of magnitude higher at the downwind locations relative to near-source data. This was attributed to the elevated local background Hg at ground level (4.0 ng m−3) likely due to emissions from outgassing lava fields. The background-corrected plume Hg/SO2 mass ratio (5.6 × 10−8) therefore appeared conservative from the near-source to several hundred meters distant, which has important implications for the upscaling of volcanic Hg fluxes based on SO2 measurements. Using this ratio and the total SO2 flux from both eruptions, we estimate the total mass of gaseous Hg released from the 2021 and 2022 Fagradalsfjall eruptions was 46 ± 33 kg, equivalent to a flux of 0.23 ± 0.17 kg d−1. This is the lowest Hg flux estimate in the literature for active open-conduit volcanoes, which range from 0.6 to 12 kg d−1 for other hotspot/rift volcanoes, and 0.5–110 kg d−1 for arc volcanoes. Our results suggest that Icelandic volcanic systems are fed from an especially Hg-poor mantle. Furthermore, we demonstrate that the aerial near-source plume Hg measurement is feasible with a drone-based active sampling configuration that captures all gaseous and particulate Hg species, and recommend this as the preferred method for quantifying volcanic Hg emissions going forward.

Bilateral simultaneous sampling of the cavernous and inferior petrosal sinuses in the differential diagnosis of Cushing’s disease

Background. Currently, the “gold standard” of differential diagnosis of Cushing’s disease is inferior petrosal sinus sampling and measurement of the adenocorticotropic hormone (ACTH) level. The studied literature data indicate a wide variability in the sensitivity and specificity of inferior petrosal sinus sampling in the range of 85–100 and 67–100 %, respectively, which can lead to an erroneous diagnosis of the source of ACTH hyperproduction and, as a consequence, to incorrect and untimely treatment.Aim.To improve the results of differential diagnosis of Cushing»s disease by using bilateral simultaneous sampling of the cavernous and inferior petrosal sinuses.Materials and methods. Cohort single-center retro/prospective study of 70 patients with confirmed ACTH-dependent Cushing’s syndrome. For the purpose of differential diagnosis, a number of indicators were calculated: central-peripheral ratio, prolactin-normalized ACTH ratio, successful catheterization. Sampling results were evaluated in comparison with contrast-enhanced pituitary magnetic resonance imaging data and intraoperative data.Results. The study of the central-peripheral ratio showed the need to assess it simultaneously at the level of the cavernous and inferior petrosal sinuses. This approach makes it possible to significantly increase the sensitivity and specificity of the applied gradient to 93.1 and 85.7 %, respectively. Prolactin-normalized ACTH ratio is a second line predictor in the differential diagnosis of Cushing’s disease with sensitivity and specificity reaching 94.7 and 28.6 %, respectively. The gradient of successful catheterization is a reflection of possible hemodynamic features of a particular sinus, does not serve as an indicator of the correct positioning of microcatheters in the vascular bed.Conclusion. Bilateral simultaneous sampling of the cavernous and inferior petrosal sinuses is an effective method of differential diagnosis of Cushing’s disease and ectopic ACTH-dependent syndrome.

Kinetics of insulin and C-peptide and estimation of prehepatic insulin secretion rates after intravenous glucose stimulation using arterial versus venous blood sampling in healthy males

An intravenous glucose-infusion of 0.3 g glucose per Kg body weight was administered over 1 min in nine healthy males with simultaneous blood sampling from the hepatic vein, femoral artery and a peripheral vein. Insulin secretion rates (ISR) were determined by the Eaton method and the ISEC method using C-peptide concentrations from arterial and peripheral venous blood. First phase (0–10 min), second phase (10–60 min), and total insulin secretion (0–60 min) were calculated as the incremental areas (iAUC) above baseline. The primary endpoint was first phase insulin response. The first phase insulin response in artery and venous blood did not differ with the Eaton method (p = 0.25), but was significantly greater with the ISEC method in arterial compared with venous blood (p < 0.05). The first phase insulin responses did not differ between methods in artery (p = 0.73) or venous blood (p = 0.73). The first phase responses of insulin and C-peptide were significant higher in the hepatic vein compared with those in the artery (p < 0.05) and peripheral vein (p < 0.05) but did not differ significantly between the artery compared with the peripheral vein for insulin (p = 0.09) or C-peptide (p = 0.26). Prehepatic insulin secretion rates did not differ between the Eaton and ISEC methods, but with the ISEC method the first phase insulin response was significantly greater in arterial compared with venous blood. The first phase insulin response differs when calculated from plasma insulin or C-peptide and depends on sample sites.

The Value of Next-Generation Sequencing in Diagnosis and Therapy of Critically Ill Patients with Suspected Bloodstream Infections: A Retrospective Cohort Study.

Bloodstream infection (BSI), a frequent cause of severe sepsis, is a life-threatening complication in critically ill patients and still associated with a high mortality rate. Rapid pathogen identification from blood is crucial for an early diagnosis and the treatment of patients with suspected BSI. For this purpose, novel diagnostic tools on the base of genetic analysis have emerged for clinical application. The aim of this study was to assess the diagnostic value of additional next-generation sequencing (NGS) pathogen test for patients with suspected BSI in a surgical ICU and its potential impact on antimicrobial therapy. In this retrospective single-centre study, clinical data and results from blood culture (BC) and NGS pathogen diagnostics were analysed for ICU patients with suspected BSI. Consecutive changes in antimicrobial therapy and diagnostic procedures were evaluated. Results: 41 cases with simultaneous NGS and BC sampling were assessed. NGS showed a statistically non-significant higher positivity rate than BC (NGS: 58.5% (24/41 samples) vs. BC: 21.9% (9/41); p = 0.056). NGS detected eight different potentially relevant bacterial species, one fungus and six different viruses, whereas BC detected four different bacterial species and one fungus. NGS results affected antimicrobial treatment in 7.3% of cases. Conclusions: NGS-based diagnostics have the potential to offer a higher positivity rate than conventional culture-based methods in patients with suspected BSI. Regarding the high cost, their impact on anti-infective therapy is currently limited. Larger randomized prospective clinical multicentre studies are required to assess the clinical benefit of this novel diagnostic technology.

Cerebral venous biomarkers and veno-arterial gradients: untapped resources in Alzheimer's disease.

Blood based biomarkers (BBB) derived from forearm veins for estimating brain changes is becoming ubiquitous in Alzheimer's Disease (AD) research and could soon become standard in routine clinical diagnosis. However, there are many peripheral sources of contamination through which concentrations of these metabolites can be raised or lowered after leaving the brain and entering the central venous pool. This raises the issue of potential false conclusions that could lead to erroneous diagnosis or research findings. We propose the use of simultaneous sampling of internal jugular venous and arterial blood to calculate veno-arterial gradient, which can reveal either a surplus or a deficit of metabolites exiting the brain. Methods for sampling internal jugular venous and arterial blood are described along with examples of the use of the veno-arterial gradient in non-AD brain research. Such methods in turn could help better establish the accuracy of forearm venous biomarkers.

Simultaneous sampling of both cingulate gyri using a single interhemispheric depth electrode: A technical note.

Simultaneous sampling of the cingulate gyri through a single depth electrode inserted underneath the falx cerebri is clinically useful in certain cases of drug-resistant epilepsy. However, the frequency at which each region of the cingulate gyri - namely, anterior, middle, and posterior - can be simultaneously sampled with a single electrode remains uncertain. We assessed the anatomical relationship between the falx cerebri and the cingulate gyrus in 50 adults and children. Subsequently, we determined whether an arbitrary line, denoted as A (representing a 5 mm gap between the falx cerebri and corpus callosum necessary for depth electrode insertion), fell within the anterior, middle, or posterior cingulate gyrus. The shape of the falx cerebri and its intersection point with the corpus callosum varied substantially across individuals, with a significant difference between children and adults (P = 0.02). The A line was located in the middle cingulate gyrus in 18 children (72%), while 3 (12%) and 4 (16%) had it located in the posterior and anterior cingulate gyrus, respectively. Among adults, 15 individuals (60%) had the A line in the middle cingulate gyrus, 10 (40%) in the posterior cingulate gyrus, and none in the anterior cingulate gyrus. This study demonstrates the feasibility of simultaneous sampling of both the anterior and middle cingulate gyri in adults and children. Moreover, it represents the first investigation to document the wide interindividual variability in the morphology of the falx cerebri and its association with the cingulate gyrus.

Cardiac MR Fingerprinting: Overview, Technical Developments, and Applications.

Cardiovascular magnetic resonance (CMR) is an established imaging modality with proven utility in assessing cardiovascular diseases. The ability of CMR to characterize myocardial tissue using T1- and T2-weighted imaging, parametric mapping, and late gadolinium enhancement has allowed for the non-invasive identification of specific pathologies not previously possible with modalities like echocardiography. However, CMR examinations are lengthy and technically complex, requiring multiple pulse sequences and different anatomical planes to comprehensively assess myocardial structure, function, and tissue composition. To increase the overall impact of this modality, there is a need to simplify and shorten CMR exams to improve access and efficiency, while also providing reproducible quantitative measurements. Multiparametric MRI techniques that measure multiple tissue properties offer one potential solution to this problem. This review provides an in-depth look at one such multiparametric approach, cardiac magnetic resonance fingerprinting (MRF). The article is structured as follows. First, a brief review of single-parametric and (non-Fingerprinting) multiparametric CMR mapping techniques is presented. Second, a general overview of cardiac MRF is provided covering pulse sequence implementation, dictionary generation, fast k-space sampling methods, and pattern recognition. Third, recent technical advances in cardiac MRF are covered spanning a variety of topics, including simultaneous multislice and 3D sampling, motion correction algorithms, cine MRF, synthetic multicontrast imaging, extensions to measure additional clinically important tissue properties (proton density fat fraction, T2*, and T1ρ), and deep learning methods for image reconstruction and parameter estimation. The last section will discuss potential clinical applications, concluding with a perspective on how multiparametric techniques like MRF may enable streamlined CMR protocols. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 1.

Dynamic multimedia approach for source apportionment of polycyclic aromatic hydrocarbons

This study was performed to evaluate the variable indicators of polycyclic aromatic hydrocarbons (PAHs) source apportionment by using an unsteady-state multimedia model. The identical indicators have been used in different environmental bulks for more than 20 years, which resulted in huge errors in source apportionment. Generated through four emission arrays, the diagnostic ratios for indicators revealed dimensionless OR, in air/soil and seawater/sediment reached ∼3.63 and ∼0.24 for Fla/Pyr, and for Ant/Phe the ratio was ∼0.31 and ∼0.18, and coastal OR for air/seawater was higher than the offshore, suggesting both compartmental and spatial divergences. The PCA indicated similar loading distribution and primary factors, shared by emission, atmosphere, and seawater arrays, whereas the slow transport between air/water and soil/sediment, weak degradation, and original concentration level might result in factors in soil and sediment separated or merged in dynamic conditions. The physicochemical divergence of indicators could be intensified after long-term environmental transport, misleading the source apportionment. Therefore, the result elucidated the essential evaluation of additional inorganic indicators and necessary verification by simultaneous sampling measurement on vertical compartments.

Effect of albumin substitution on pharmacokinetics of piperacillin/tazobactam in patients with severe burn injury admitted to the ICU.

Pathophysiological changes in severely burned patients alter the pharmacokinetics (PK) of anti-infective agents, potentially leading to subtherapeutic concentrations at the target site. Albumin supplementation, to support fluid resuscitation, may affect pharmacokinetic properties by binding drugs. This study aimed to investigate the PK of piperacillin/tazobactam in burn patients admitted to the ICU before and after albumin substitution as total and unbound concentrations in plasma. Patients admitted to the ICU and scheduled for 4.5 g piperacillin/tazobactam administration and 200 mL of 20% albumin substitution as part of clinical routine were included. Patients underwent IV microdialysis, and simultaneous arterial plasma sampling, at baseline and multiple timepoints after drug administration. PK analysis of total and unbound drug concentrations under steady-state conditions was performed before and after albumin supplementation. A total of seven patients with second- to third-degree burns involving 20%-60% of the total body surface were enrolled. Mean (SD) AUC0-8 (h·mg/L) of total piperacillin/tazobactam before and after albumin substitution were 402.1 (242)/53.2 (27) and 521.8 (363)/59.7 (32), respectively. Unbound mean AUC0-8 before and after albumin supplementation were 398.9 (204)/54.5 (25) and 456.4 (439)/64.5 (82), respectively. Albumin supplementation had little impact on the PK of piperacillin/tazobactam. After albumin supplementation, there was a numerical increase in mean AUC0-8 of total and unbound piperacillin/tazobactam, whereas similar Cmax values were observed. Future studies may investigate the effect of albumin supplementation on drugs with a higher plasma protein binding.

Evaluation of a wearable fabric-based sensor for accurate sodium determination in sweat during exercise.

Newly developed wearable fabric sensors (WFS) can increase the ease and accuracy of sweat sodium measurements by performing simultaneous sampling and analysis on the body during exercise. Determine the accuracy of a WFS for measurement of sodium concentration in sweat. Subjects wore a WFS prototype and sweat collectors on their forearm during cycle ergometry. Subjects exercised at a moderate intensity (~ 65% heart rate reserve) for 30-60min. Sweat samples were collected and analyzed using a commercial sweat sodium analyzer (SSA) every 10-15min. WFS were adhered with an armband and connected to custom built electronics. Accuracy was determined by comparing predicted WFS concentration to the actual concentration from the commercial SSA and analyzed statistically using ANOVA and Bland-Altman plots. A total of 19 subjects completed the study. The average sweat sodium concentration was 59mM ± 22mM from a SSA compared with 54mM ± 22mM from the WFS. Overall, the average accuracy of the WFS was 88% in comparison to the SSA with p = 0.45. A line of best fit comparing predicted versus actual sweat sodium concentration had a slope of 0.99, intercept of - 4.46, and an r2 of 0.90. Bland-Altman analysis showed the average concentration difference between the WFS and the SSA was 5.35mM, with 99% of data points between ± 1.96 times the standard deviation. The WFS accurately predicted sweat sodium concentration during moderate intensity cycle ergometry. With the need for precise assessment of sodium loss, especially during long duration exercise, this novel analysis method can benefit athletes and coaches. Further research involving longer duration and more intense exercise is warranted.

Ab Initio Prediction of 3-D Conformations for Protein Long Loops with High Accuracy and Applications to Antibody CDRH3 Modeling.

Residue-level potentials of mean force were widely used for protein backbone refinements to avoid simultaneous sampling of side-chain conformations. The interaction energy between the reduced side chains and backbone atoms was not considered explicitly. In this study, we developed novel methods to calculate the residue-atom interaction energy in combination with atomic and residue-level terms. The parameters were optimized step by step to remove the overcounting or overlap problem between different energy terms. The mixing energy functions were then used to evaluate the generated backbone conformations at the initial sampling stage of protein loop modeling (OSCAR-loop), including the interaction energy between the reduced loop residues and full atoms of the protein framework. The accuracies of top-ranked decoys were 1.18 and 2.81 Å for 8-residue and 12-residue loops, respectively. We then selected diverse decoys for side-chain modeling, backbone refinement, and energy minimization. The procedure was repeated multiple times to select one prediction with the lowest energy. Consequently, we obtained an accuracy of 0.74 Å for a prevailing test set of 12-residue loops, compared with >1.4 Å reported by other researchers. The OSCAR-loop was also effective for modeling the H3 loops of antibody complementary determining regions (CDRs) in the crystal environment. The prediction accuracy of OSCAR-loop (1.74 Å) was better than the accuracy of the Rosetta NGK method (3.11 Å) or those achieved by deep learning methods (>2.2 Å) for the CDRH3 loops of 49 targets in the Rosetta antibody benchmark. The performance of OSCAR-loop in a model environment was also discussed.

Microdialysis as a sampling tool for the chemotherapeutic agent Doxorubicin

Doxorubicin is a chemotherapeutic agent used for more than fifty years to treat a great variety of cancers in both children and adults. Despite hereof, pharmacokinetic knowledge is almost solely based on systemic plasma concentrations. Microdialysis is a catheter-based pharmacokinetic sampling tool enabling simultaneous target site sampling of unbound molecules of interest. The aim of this study was to thoroughly evaluate the feasibility of applying microdialysis for sampling of Doxorubicin in both in vitro experiments and an in vivo setting. Doxorubicin relative recovery by gain and by loss was tested for different catheter types, perfusion fluids, concentrations and collection vials. Adsorption tests revealed polystyrene/santoprene vials to be the biggest contributor of unwanted adsorption between Doxorubicin and the microdialysis equipment, and confirmed LoBind Eppendorf tubes to be a suitable alternative. The methodological combination of polyamide membranes, saline as perfusion fluid and LoBind Eppendorf sampling tubes demonstrated no statistically significant differences for relative recovery by gain and by loss, and the relative recovery was also found to be concentration independent. We conclude, that a proper microdialysis set-up can be used to collect samples containing concentrations of the chemotherapeutic drug Doxorubicin in vitro and in vivo, which encourage future pharmacokinetic studies to evaluate current treatment regimens to find the most effective and least toxic anti-neoplastic treatment for the patients.

VALUE ADDITION OF ERI SILK YARNS WITH ALLAMANDA GRANDIFLORA - A NATURAL COLOURANT

Eri silk is one of the four varieties of silk mostly available in northeastern region of India. Recent trends in the world market of silk revealed that eri silk had tremendous potential as it was gifted with unique properties of protecting human body from some aliments as well as its use as fashionable dress and furnishing materials besides providing comfort of warmth. To suit the norms of the present national and international market, dyeing eri silk with natural dyes contributes to its value chain. The information on dyeing eri silk with natural dyes is very meager and requires to be established. New source such as Allamanda grandiflora was not used for dyeing textiles as per the available literature. Effort was made to standardise variables involved in extraction of the dyes and dyeing eri silk yarns. The standardisation procedures described under materials and methods were used and the evaluation was based on colour strength (K/S values) measured using colour flex spectrophotometer. Among the three mordanting methods, Pre mordanting method exhibited better results compare with simultaneous and post mordanted samples. Among the five mordants, alum and chitin mordanted samples exhibited good fastness followed by tartaric acid, ferrous sulphate and stannous chloride mordanted samples.

Multi-detector simultaneous sampling design in the spot-scanning defects detection system

With the decreases in semiconductor critical dimension and increases in circuit intricacy, the impact of wafer defects on the yield and manufacturing cost of integrated circuits is becoming increasingly significant. In this paper, a multimodal spot-scanning defect detection system designed for unpatterned wafer surfaces is introduced. The defect detection system's mechanics, electronics, and software are introduced, focusing on presenting a multi-detector simultaneous sampling design. The signal sampling is based on the position triggering of the rotary stage encoder. The focused illumination spot is scanned in a helical trajectory relative to the wafer in coordination with the motion of the linear stage and rotary stage. The signal detection is carried out synchronously, and the signal sampling is triggered by rotary stage encoder position pulses to achieve equally spaced sampling. The detector signals are trans-impedance amplified and transmitted differentially to transfer the analogue signals from the optical head to the main control board. Under FPGA control, the main control board completes the simultaneous sampling and signal processing through nine high-precision 16-bit SAR(successive-approximation-register) ADCs(analogue-to-digital converter) under the trigger signal. The defect detection system is designed with a pixel resolution of 4 × 4 μm, requiring a sampling position error of less than 1 pixel and an inter-channel position deviation of less than 0.1 pixel. The rotary stage prototype has a design speed of 120 rpm, and the positioning accuracy of the encoder is ±8 arcsec. Therefore, the maximum sampling position error is 1.94 μm for a 4-inch wafer sample. The maximum phase deviation between the nine channels is 32.5 ns, and the maximum position deviation is 20.4 nm.

Applicability of environmental DNA metabarcoding for the hyporheic zone of a stream bed

AbstractHyporheic zones play a crucial role in ecological processes primarily orchestrated by hyporheic organisms, known as hyporheos. Our understanding of riverine biodiversity, encompassing hyporheic zones, remains limited. Therefore, the development of a method for the facile and accurate detection of hyporheic communities is imperative. Thus, we evaluated the applicability of environmental DNA (eDNA) metabarcoding surveys in the hyporheic zone in a small stream in Japan. We conducted simultaneous direct sampling and eDNA surveys at two different locations (head and tail of a rapid and a bar) and during two different seasons (less and more disturbed periods). Subsequently, we compared the outcomes of these sampling methods, locations, and seasons. Through eDNA metabarcoding targeting the cytochrome‐c oxidase subunit I (COI) regions, we successfully identified a diverse array of hyporheic and benthic taxa in all samples. Remarkably, the performance of eDNA metabarcoding was comparable to the identification of directly sampled benthos and hyporheos. We observed a 62%–78% concordance between direct sampling and eDNA metabarcoding. Notably, eDNA metabarcoding revealed a higher number of hyporheic taxa compared to direct sampling. Moreover, the relative detectability of hyporheos by eDNA metabarcoding differed between the seasons, unlike direct sampling. Our findings underscore the importance of conducting both eDNA surveys and direct sampling to comprehensively assess the composition of the stream community while accounting for seasonal variations. This study demonstrates the utility of eDNA metabarcoding as a non‐destructive approach for investigating the hyporheic zone, enabling a more effective assessment of riverine biodiversity.

Parasite assemblages in volatile host stocks: inter- and intra-cohort variability restrict their value as biological tags for squid stock assessment.

The Argentine shortfin squid, Illex argentinus, inhabits in the southwest Atlantic; it is a semelparous species which grows rapidly along its 1 year lifespan. The identification of its stocks is critical for sustainable fishery exploitation. Parasites have been used as biological indicators in a lower number of studies dealing with squids, therefore a validation of this methodology is necessary. The intra- and inter-cohort variability of parasite assemblages in the summer-spawning stock of I. argentinus was analysed to assess their value as indicators of stock structure. Four squid samples from the continental shelf of central Patagonia, corresponding to 3 consecutive cohorts, were examined for metazoan parasites. Results evidenced heterogeneity in terms of parasite assemblage composition and structure, dominated by short-lived gastrointestinal parasites, with a strong influence of host size, but no effect of squid sex. These changes are related to their recent habitats and diets, which change with ontogeny and migrations, clouding any interpretation of patterns when samples spatially or temporally separated are compared. Many squid species share these characteristics; therefore, it is recommended that the use of parasites as biological tags should be restricted to simultaneous sampling, while size or age must be considered for deriving proper conclusions.