Pool Volume Research Articles

Hepatic steatosis is associated with abnormal hepatic enzymes, visceral adiposity, altered myocardial glucose uptake measured by 18F-FDG PET/CT

BackgroundNonalcoholic fatty liver disease (NAFLD) is a multisystem disease that affects the liver and a variety of extra-hepatic organ systems. This study aimed to investigate the relationship between hepatic steatosis and glucose metabolism in liver and extra-hepatic tissues and organs.MethodsThe whole body 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) images of 191 asymptomatic tumor screening patients were retrospectively analyzed. Patients with the ratio of spleen/liver CT densities > 1.1 were defined to have NAFLD, and their clinical symptoms, laboratory markers, FDG uptake in a variety of tissues and organs including heart, mediastinal blood pool, liver, spleen, pancreas, and skeletal muscle, as well as abdominal adipose tissue volumes including visceral adipose tissue (VAT) volume and subcutaneous adipose tissue (SAT) volume were compared with those of the non-NAFLD patients and used to analyze the independent correlation factors of NAFLD.ResultsAmong the 191 patients, 33 (17.3%) were NAFLD, and 158 (82.7%) were non-NAFLD. There was no significant correlation between the mean standardized uptake value (SUVmean) and CT density of liver as well as the ratio of spleen/liver CT densities. Hepatic steatosis, but not FDG intake, was more significant in NAFLD patients with abnormal liver function than those with normal liver function. Compared with the non-NAFLD patients, NAFLD patients had significantly reduced myocardial glucose metabolism, but significantly increased mediastinal blood pool, spleen SUVmean and abdominal adipose tissue volumes (including VAT and SAT volumes) (P < 0.05). Multivariate regression analysis showed that elevated serum ALT, increased abdominal VAT volume, and decreased myocardial FDG uptake were independent correlation factors for NAFLD. Further studies showed that hepatic steatosis and myocardial FDG uptake were mildly linearly correlated (r = 0.366 with hepatic CT density and − 0.236 with the ratio of spleen/liver CT densities, P < 0.05).ConclusionsNAFLD is a systemic disease that can lead to the change of glucose metabolism in some extra-hepatic tissues and organs, especially the myocardium.

Neural correlates of winning and losing fights in poison frog tadpoles

Aggressive competition for resources among juveniles is documented in many species, but the neural mechanisms regulating this behavior in young animals are poorly understood. In poison frogs, increased parental care is associated with decreased water volume of tadpole pools, resource limitation, and aggression. Indeed, the tadpoles of many poison frog species will attack, kill, and cannibalize other tadpoles. We examined the neural basis of conspecific aggression in Dyeing poison frog (Dendrobates tinctorius) tadpoles by comparing individuals that won aggressive encounters, lost aggressive encounters, or did not engage in a fight. We first compared patterns of generalized neural activity using immunohistochemical detection of phosphorylated ribosomes (pS6) as a proxy for neural activation associated with behavior. We found increased neural activity in the medial pallium and preoptic area of loser tadpoles, suggesting the amphibian homologs of the mammalian hippocampus and preoptic area may facilitate loser-associated behaviors. Nonapeptides (arginine vasotocin and mesotocin) and dopamine have been linked to aggression in other vertebrates and are located in the preoptic area. We next examined neural activity specifically in nonapeptide- and tyrosine-hydroxylase-positive cells using double-label immunohistochemistry. We found increased neural activity specifically in the preoptic area nonapeptide neurons of winners, whereas we found no differences in activity of dopaminergic cells among behavioral groups. Our findings suggest the neural correlates of aggression in poison frog tadpoles are similar to neural mechanisms mediating aggression in adults and juveniles of other vertebrate taxa.

Short Selling and Dark Pool Volume

Prior research posits that traders with short-lived information favor lit exchanges over dark pools due to execution certainty. This paper focuses on the relation between informed trading based on firm fundamentals and dark pool volume because the preferred venue for traders with longer-lived information is less certain. The proportion of trading volume executed in dark pools is positively correlated with short interest. This result is stronger for stocks that suffer from greater uncertainty and stocks targeted by transient institutional investors. Short sellers profit substantially from their information as subsequent returns are lower for heavily shorted stocks with greater dark pool volume.

Nowhere to swim: interspecific responses of prairie stream fishes in isolated pools during severe drought

Extreme drying can dramatically shift abiotic characteristics of streams and species respond differently as conditions change. We modified a conceptual model describing responses of aquatic invertebrate assemblages to stream drying to facilitate predictions of fish assemblage shifts in which thresholds of physiochemical gradients lead to punctuated losses of fish diversity as stream connectivity diminishes. We tested the applicability of this model during a record-breaking drought that reduced a perennial reach of a headwater prairie stream to a series of 12 isolated pools with variable levels of hyporheic connectivity that was associated with pool volume. We tracked fish assemblage structure in pools over seven weeks and measured abiotic conditions. Inter-specific differences in drought resistance traits were tested in the lab (i.e., thermal and hypoxia tolerance) for common species experiencing drought conditions. Species richness declined rapidly with pool volume associated with hyporheic connectivity. Abundance of the most common species prior to drought, Chrosomus erythrogaster (southern redbelly dace) declined 95% and was extirpated from five pools during drought due to its low thermal tolerance. Despite being the least tolerant to hypoxia, Campostoma anomalum (central stoneroller) populations persisted in most pools. The remaining pools became dominated by a non-native extremophile fish, Gambusia affinis (western mosquitofish) and abundances of less resistant native species declined. Our study demonstrates that richness in drying pools is driven by factors associated with pool volume, and assemblage composition shifts from dominance by native species adapted to variable hydrological conditions to non-native species able to resist increasing temperatures and hypoxia. Sudden species loss associated with reduced stream connectivity can shift abundance patterns of prairie stream fish communities with potentially lagged effects on population and community dynamics.

Combining Statistical Shape Model and Principal Component Analysis to Estimate Left Ventricular Volume and Ejection Fraction.

Left ventricular ejection fraction (LVEF) assessment is instrumental for cardiac health diagnosis, patient management, and patient eligibility for participation in clinical studies. Due to its non-invasiveness and low operational cost, ultrasound (US) imaging is the most commonly used imaging modality to image the heart and assess LVEF. Even though 3D US imaging technology is becoming more available, cardiologists dominantly use 2D US imaging to visualize the LV blood pool and interpret its area changes between end-systole and end-diastole. Our previous work showed that LVEF estimates based on area changes are significantly lower than the true volume-based estimates by as much as 13%,1 which could lead to unnecessary and costly therapeutic decisions. Acquiring volumetric information about the LV blood pool necessitates either time-consuming 3D reconstruction or 3D US image acquisition. Here, we propose a method that leverages on a statistical shape model (SSM) constructed from 13 landmarks depicting the LV endocardial border to estimate a new patient's LV volume and LVEF. Two methods to estimate the 3D LV geometry with and without size normalization were employed. The SSM was built using the 13 landmarks from 50 training patient image datasets. Subsequently, the Mahalanobis distance (with size normalization) or the vector distance (without size normalization) between an incoming patient's LV landmarks and each shape in the SSM were used to determine the weights each training patient contributed to describing the new, incoming patient's LV geometry and associated blood pool volume. We tested the proposed method to estimate the LV volumes and LVEF for 16 new test patients. The estimated LVEFs based on Mahalanobis distance and vector distance were within 2.9% and 1.1%, respectively, of the ground truth LVEFs calculated from the 3D reconstructed LV volumes. Furthermore, the viability of using fewer principal components (PCs) to estimate the LV volume was explored by reducing the number of PCs retained when projecting landmarks onto PCA space. LVEF estimated based on 3 PCs, 5 PCs, and 10 PCs are within 6.6%, 5.4%, and 3.3%, respectively, of LVEF estimates using the full set of 39 PCs.

Effect of Heat Input Parameters on Molten Pool Size during Selective Laser Melting of Ti-6Al-4V Powder Through Numerical Simulation

Numerical simulations were proposed to research the influence of heat input parameters on the melting pool dimension and temperature field distribution during the selective laser melting process of Ti-6Al-4V powder. Firstly, temperature field results demonstrate that in the same powder layer, the center part of the sample will experience three more obvious heating processes under the irradiation of laser. Secondly, a good exponential function relationship is found between the melting pool dimension and volume energy density. Finally, based on the melting pool dimension from our numerical simulations, two full-process energy prediction diagrams are drawn to predict hatch spacing and powder layer thickness of SLM Ti-6Al-4V powder, consistent with the experimental results.

Steroid profile of porcine follicular fluid and blood serum: Relation with follicular development.

The aim of this study was to identify follicular fluid (FF) steroids which reflect follicular development in the early stages of the follicular phase and to establish whether the levels of these FF steroids correspond to their levels in serum. If these relations are established, serum steroid profiles may be used to monitor follicular development already in this early stage of the follicular phase. We used samples of two experiments, one with multiparous sows at the onset of the follicular phase (weaning) and one with primiparous sows at the midfollicular phase (48 hr after weaning). Complete steroid profiles were measured in pooled FF of the 15 largest follicles and serum using high‐performance liquid chromatography‐tandem mass spectrometry. In experiment 1, pooled FF volume, as a measure for average follicle size, tended to be positively related to higher FF 17β‐estradiol levels (β = 0.56, p = .08). In experiment 2, a larger FF volume was related not only to FF higher 17β‐estradiol levels (β = 2.11, p < .001) but also to higher levels of β‐nortestosterone (β = 1.15, p < .0001) and its metabolite 19‐norandrostenedione (β = 1.27, p < .01). In addition, FF volume was related to higher FF 17α‐OH‐pregnenolone (β = 1.63, p = .03) and 17α‐OH‐progesterone (β = 1.83, p < .001), which could indicate that CYP17,20‐lyase activity is limiting for 17β‐estradiol production in larger follicles at the beginning of the follicular phase. In serum, most of the steroids were present at lower levels compared to FF, except for the corticosteroids. Serum progestins and androgens were never related to follicle pool volume and steroid levels did not differ in the midfollicular phase compared to the onset of the follicular phase in the second experiment. Serum steroid levels therefore poorly reflect the developmental stage of the follicle pool in the first half of the follicular phase of the estrous cycle in sows.

Numerical study of the effects and transport mechanisms of iron vapour in tungsten inert-gas welding in argon

Tungsten inert-gas (TIG) welding uses an electric arc between a tungsten cathode and a metal anode to partially melt the anode workpiece, forming a weld pool. Metal vapour emanating from the weld pool has important effects on the arc welding process. An axisymmetric computational model of the arc and weld pool is used to examine the transport and influence of iron vapour on an argon arc plasma. In contrast to previous studies that use approximate and incomplete treatments of diffusion, the present model incorporates the combined diffusion coefficient method, which takes into account all important driving forces. The influence of metal vapour is first examined for an arc current of 400 A. Metal vapour is predicted to be present in high concentrations above the anode and near the cathode tip, and in a lower concentration in the arc column. The presence of metal vapour in the arc is found to lead to a substantial reduction in arc temperature (up to 1600 K) and current density, resulting in a significant decrease in the weld pool depth and volume. It is shown that ordinary diffusion leads to iron vapour transport upward from the anode region along the arc fringes and into the recirculating convective flow, which carries the iron vapour to the cathode region. Here the upward diffusion driven by the electric field and temperature gradient traps the iron vapour below the cathode tip, leading to a high concentration in this region. The influence of arc current is investigated in the range from 150 to 400 A. The results obtained for standard welding currents of 150, 200 and 250 A also predict significant concentrations of iron vapour in the arc, with the concentration increasing with current in the arc column and near the anode. The concentration near the cathode tip is lower at 400 A because the temperature and electric field diffusion coefficients are lower at the higher temperatures present near the cathode. Spectroscopic measurements of atomic chromium emission for argon TIG welding of a chromium anode are presented and compared to predictions of the code. The measurements show the presence of metal vapour in both the cathode and anode regions, in agreement with the model.

Efficient capture of monoclonal antibody from cell culture supernatant using protein A media contained in a cuboid packed-bed device

A box-shaped or cuboid packed-bed device was used for monoclonal antibody (mAb) separation using protein A affinity chromatography. The separation efficiency of the device was compared with an equivalent column i.e. packed with same resin, and having identical bed height and bed volume. The protein A media packed cuboid device had a larger number of theoretical plates than its equivalent column, e.g. 8750/m as opposed to about 4700/m at a flow rate of 0.5 mL/min. In mAb purification experiments, the impurity flow-through and eluted mAb peaks were shaper with the cuboid device. This implied that the effective separation time and buffer consumption with this device was lower, the purified mAb pooled volume was smaller, and the mAb concentration in the pooled volume was greater. Equivalent separation efficiency could be obtained with the cuboid device using higher flow rates than that used with the column. For instance, elution peaks equivalent to those obtainable by the column could be obtained at a 5 times greater flow rate using the cuboid device. The results discussed in this paper clearly demonstrate the potential for improving the efficiency of protein A affinity chromatography based mAb purification by using a cuboid packed-bed device.

The abundance and larval performance of Aedes phoeniciae in supralittoral rock-pools

The mosquito Aedes phoeniciae is a potential disease vector that inhabits the coastal rock-pools of the Southeastern Mediterranean Sea. Our year-long study examined the abundance and distribution of Ae. phoeniciae in 49 rock-pools along HaBonim Beach Nature Reserve (Israeli coast) on a monthly basis (September 2016 to August 2017). Additionally, the physical, chemical, and biological characteristics of the rock-pools were measured. Our results showed a correlation between the abundance of Ae. phoeniciae and abiotic (salinity, pool volume, and pH) and biotic (bacterial, micro-phytoplankton, and chironomid abundance) characteristics. A complementary experiment was conducted to examine the role of bacteria and phytoplankton on Ae. phoeniciae larval performance by rearing larvae in seawater (SW) or seawater without microbes (FSW, 0.2-µm). Ae. phoeniciae grown in SW exhibited a high survivorship rate (~ 77%), while lower survivorship rate was measured in the FSW treatments (~ 45%). Furthermore, a higher number of adult females were found in the SW compared to FSW treatments (35 and 11, respectively), while the number of male adults remained similar. Our results suggest that Ae. phoeniciae larvae rely on the water characteristics and especially on the microbial communities that habitat the rock-pools. These results may enable improved mosquito control of Ae. phoeniciae along the Southeastern Mediterranean Sea.

Flat Panel Computed Tomography Pooled Blood Volume and Infarct Prediction in Endovascular Stroke Treatment.

Background and Purpose- Patients with large-vessel stroke frequently need to be transferred to comprehensive stroke centers for endovascular treatment. An update of physiological perfusion parameters and stroke progression on arrival is desirable. We examined the reliability of preinterventional pooled blood volume (PBV)-maps acquired by flat-panel detector computed tomography (CT) in the interventional angiography suite. Methods- The volumes of preinterventional perfusion deficit in flat-panel detector CT-PBV source images were compared with final infarct volume on follow-up multislice-CT after endovascular treatment of 29 consecutive patients with occlusion of the middle cerebral artery (MCA) or the distal internal carotid artery (ICA). Results- Endovascular treatment was successful in 26 patients (Thrombolysis in Cerebral Infarction, 2b-3). Overall, the median preinterventional PBV-deficit was 9×larger than median final infarct volume on multislice-CT (86.4 mL [10.3; 111.6] versus 9.6 mL [3.6; 36.8]). This was especially evident in the subgroup of successful recanalization (PBV-deficit: 87.5 mL [10.6; 115.1], final infarct: 8.7 mL [3.6; 29]). In futile recanalization, the final infarct tended to be underestimated (PBV-deficit: 86.4 mL [5.9; -] and final infarct: 116.4 mL [3.5; -]). Conclusions- Flat panel detector CT-PBV is not reliable in predicting the final infarct volume and should not be used in clinical decision making for endovascular treatment of acute cerebral artery occlusions.

Cathode-focused high-current arc: Heat source development with stable keyhole in stationary welding

A three-dimensional numerical model was established to investigate the thermal coupling mechanism in the K-TIG (Keyhole Tungsten Inert Gas) keyhole and weld pool. Especially, to reflect the energy distribution in the new-developed high-current free burning arc, a novel, suitable combined heat source model was proposed. The dynamic process of heat source and the corresponding temperature field were studied to reflect the effect of arc on the workpiece. Keyhole evolution with temperature distribution and fluid flow in the weld pool was investigated to further explore the keyhole influence on the heat transfer and mechanical energy of the weld pool. Some new features of K-TIG were discovered. The higher temperature molten metal is distributed mainly in the upper part instead of the bottom of the weld pool, and the weld pool volume of K-TIG is large, up to 50 mm3. Finally, the first emerging time of a fully penetrated keyhole, keyhole size, and fusion line size were measured in stationary welding experiments. The simulation results agreed well with the measured data. The results lay a foundation for understanding the coupling behavior in energy source-keyhole-weld pool system, and they could promote the engineering application of K-TIG process.

Investigating the combination of single‐pass tangential flow filtration and anion exchange chromatography for intensified mAb polishing

There is growing interest within the biopharmaceutical industry to improve manufacturing efficiency through process intensification, with the goal of generating more product in less time with smaller equipment. In monoclonal antibody (mAb) purification, a unit operation that can benefit from intensification is anion exchange (AEX) polishing chromatography. Single-pass tangential flow filtration (SPTFF) technology offers an opportunity for process intensification by reducing intermediate pool volumes and increasing product concentration without recirculation. This study evaluated the performance of an AEX resin, both in terms of host cell protein (HCP) purification and viral clearance, following concentration of a mAb feed using SPTFF. Results show that preconcentration of AEX feed material improved isotherm conditions for HCP binding, resulting in a fourfold increase in resin mAb loading at the target HCP clearance level. Excellent clearance of minute virus of mouse and xenotropic murine virus was maintained at this higher load level. The increased mAb loading enabled by SPTFF preconcentration effectively reduced AEX column volume and buffer requirements, shrinking the overall size of the polishing step. In addition, the suitability of SPTFF for extended processing time operation was demonstrated, indicating that this approach can be implemented for continuous biomanufacturing. The combination of SPTFF concentration and AEX chromatography for an intensified mAb polishing step which improves both manufacturing flexibility and process productivity is supported.

In-situ characterization and quantification of melt pool variation under constant input energy density in laser powder bed fusion additive manufacturing process

Size and shape of a melt pool play a critical role in determining the microstructure in additively manufactured metals. However, it is very challenging to directly characterize the size and shape of the melt pool beneath the surface of the melt pool during the additive manufacturing process. Here, we report the direct observation and quantification of melt pool variation during the laser powder bed fusion (LPBF) additive manufacturing process under constant input energy density by in-situ high-speed high-energy x-ray imaging. We show that the melt pool can undergo different melting regimes and both the melt pool dimension and melt pool volume can have orders-of-magnitude change under a constant input energy density. Our analysis shows that the significant melt pool variation cannot be solely explained by the energy dissipation rate. We found that energy absorption changes significantly under a constant input energy density, which is another important cause of melt pool variation. Our further analysis reveals that the significant change in energy absorption originates from the separate roles of laser power and scan speed in depression zone development. The results reported here are important for understanding the laser powder bed fusion additive manufacturing process and guiding the development of better metrics for processing parameter design.

Molluscan Assemblages in Rock Pools on Sandstone Reefs: Local and between Pools Variability

This study investigated the variability of molluscan assemblages of rock pools according to location and pool size. The study was carried out in three sandstone reefs on the west coast of Ceara in northeast Brazil. The size parameters evaluated were surface area, depth, and volume of pools and pool-ocean distance. The molluscan assemblages were characterized by ecological diversity descriptors (abundance, species richness, diversity, and evenness). A total of 43 species of molluscs belonging to the classes Bivalvia, Gastropoda, and Polyplacophora were identified. The most relevant species for discriminating among the assemblies were Eulithidium affine, Cerithium atratum, Tegula viridula, and Ischnochiton striolatus. Results indicated a clear local difference in the structures of the assemblages; however, they did not differ according to the size of the pools. This indicates that sites may play a more important role in the structure of molluscan assemblages in rock pools than the association with pools.

Left Ventricular Ejection Fraction Assessment: Unraveling the Bias between Area- and Volume-based Estimates.

Calculating left ventricular ejection fraction (LVEF) accurately is crucial for the clinical diagnosis of cardiac disease, patient management, or other therapeutic treatment decisions. The measure of a patient's LVEF often affects their candidacy for cardiovascular intervention. Ultrasound (US) is one of the imaging modalities used to non-invasively assess LVEF, and it is the most common and least expensive. Despite the advances in 3D US transducer technology, only limited US machines are equipped with such transducer to enable true 3D US image acquisition. Thus, 2D US images remain to be widely used by cardiologists to image the heart and their interpretation is inherently based on two dimensional information immediately available in the US images. Past knowledge indicates that visual estimation of the LVEF based on the area changes of the left ventricle blood pool between systole and diastole (as depicted in 2D ultrasound images) may significantly underestimate the ejection fraction, rendering some patients as suitable candidates for potentially unnecessary interventions or implantation of assistive devices. True LVEF should be calculated based on changes in LV volumes, but equipment and time constraint limit the current technique to assess 3D LV geometry. The estimation of the systolic and diastolic blood pool volumes requires additional work beyond a simple visual assessment of the blood pool area changed in the 2D US images. Specifically, following the manual segmentation of the endocardial LV border, 3D volume would be assessed by reconstructing a LV volume from multiple tomographic views. In this work, we leverage on two idealized mathematical models of the left ventricle - a truncated prolate spheroid (TPS) and a paraboloid geometric model to characterize the LV shape according to the range of possible dimensions gathered from our patient-specific multi-plane US imaging data. The objective of this work is to reveal the necessity of calculating LVEFs based on volumes by showing that LVEF estimated using area changes underestimate the LVEF computed using volume changes. Additionally, we present a method to reconstruct the LV volume from 2D blood pool representations identified in the multi-plane 2D US images and use the reconstructed 3D volume throughout the cardiac cycle to estimate the LVEF. Our preliminary results show that the area-based LVEF significantly underestimates the true volume-based LVEF across both the theoretical simulations using idealized geometric models of the LV shape, as well as the patient-specific US imaging data. Specifically, both the TPS and paraboloid model showed an area-based LVEF of 41.3 ± 4.7% and a volume-based LVEF of 55.4 ± 5.7%, while the US image data showed an area-based LVEF of 34.7 ± 11.9% and a volume-based LVEF of 48.0 ± 14.0%. In summary, the area-based LVEF estimations using both the idealized TPS and paraboloid models was 14.1% lower than volume- based LVEF calculations using corresponding models. Furthermore, the area-based LVEF based on reconstructed LV volumes are 13.3% lower than volume-based estimates. Evidently, there is a need to further investigate a method to enable practical volume-based LVEF calculations to avoid the need for clinicians to estimate LVEF based on visual, holistic assessment of the blood pool area changes that improperly infer volumetric blood pool changes.

Microstructure and performance of the laser melted aluminum bronze layers with and without using activator

In the present research, the surface-melted aluminum bronze were manufactured by laser remelting technology. The microstructure and properties of the melted layers with and without using activator were investigated. With increasing laser power, the width and depth of the melted layer increased, and the grain size of the melted layer became coarser due to the higher heat input and larger molten pool volume. Under the same conditions (i.e. laser power of 1000 W), the width and depth of the melted layer could be reduced and increased, respectively, with the use of the activator. In particular, the depth of melted layer increased by nearly 50%. Furthermore, to obtain the same penetration of the melted layer, the addition of the activator could reduce the heat input, which led to the decrease of grain size. The relatively small grain size and high dislocation density could improve the hardness and tribological behavior of the melted layers.

Geomorphic and retention responses following the restoration of a sand-gravel bed stream

Restoration is applied to reinstate geomorphic processes and complexity in degraded streams, but case studies of responses remain rare. A 236 m long reach of the Logie Burn, a straightened sand-gravel bed stream in north-east Scotland was restored by reconnecting its pre-modification channel to improve habitat and reduce nutrient transfer. Morphological, sedimentary and retention (wood, phosphorous and organic matter) responses were monitored over 3 years. Monitoring over 2 years was also conducted in a nearby control reach. A net deposition response of 64.3 ± 32.1 m3, a near two-fold enlargement of channel cross section area and a reduction of bed slope from 0.0008 m m−1 to 0.00014 m m−1 were observed in the restored reach over 3 years. The control reach in contrast was relatively stable. After 3 years, relative pool volume and morphological complexity were similar to the control reach and its pre-restoration state. Substrate diversity (Shannon-Wiener index: H’) after an initial increase, declined but at the end of the monitoring period was higher (H’ = 1.26) than the control reach (H’ = 1) and pre-restoration reach (H’ = 0.8). Following restoration, the median sediment size (D50) of the majority of the restored main channel reduced from 3.4 mm to 1.5 mm – a similar value to pre-restoration (D50 = 1.6 mm) – reflecting the net deposition response although the overall grain size distribution was not statistically different. No relationship between geomorphically effective flows and morphological change was found reflecting geomorphic sensitivity due to the reconnection work and wood recruitment mainly driven by tree collapse in response to channel readjustment. The retention of organic matter (OM) and total phosphorous (TP) did not increase in the main channel but did within the backwaters which also exhibited a statistically significant fining response. Overall, these results suggest that the physical habitat improvement value of the scheme so far has been limited but the creation of the backwaters may have increased the capacity of the reach to retain nutrients and fine sediment.

Automation and developmental validation of the ForenSeq™ DNA Signature Preparation kit for high-throughput analysis in forensic laboratories

Massively parallel sequencing (MPS) applications in forensic science highlight the advantages of this technique compared to capillary electrophoresis (CE). The multiplexing of a wide range of genetic markers and access to the full amplicon sequence, allowing the detection of isoalleles, make it a very promising tool which could be applied to the most challenging casework DNA samples. However, the complexity of the manual library preparation protocol, potential DNA contamination and sample tracking issues are the main reasons why forensic scientists still hesitate to implement MPS analytical workflows in their laboratory. Here, we present the automation of all library preparation steps for up to 96 samples using the Verogen’s ForenSeq™ DNA Signature Preparation kit. This automated protocol, developed on a Hamilton ID STARlet robotic platform, is designed to allow the combined sequencing of rich and poor DNA samples thanks to a final step which adjusts normalized library pooling volume to guarantee a uniform depth of coverage across all samples. Our study includes tests of concordance, repeatability, reproducibility and sensitivity (1000 pg, 700 pg, 500 pg, 250 pg, 100 pg and 50 pg). Sequencing results obtained with the automated protocol were found to be concordant with previous validation studies using the manual protocol in terms of depth of coverage and allele coverage ratio. The results of this study will assist forensic laboratories seeking to acquire a plug and play solution to optimize the processing and analysis of casework samples with MPS.

A metallurgical phase transformation framework applied to SLM additive manufacturing processes

While significant progress has been made in the last few years, the reliability of Additively Manufactured (AM) parts is often less than desirable as they suffer from manufacturing defects and hence subpar strength and fatigue life. To address this challenge, numerical methods are sought to provide insight into the process and help accelerate progress in raising the quality of AM parts. In metal AM applications, assessing the amount of unfused powder, melt pool volumes, and metallurgical phase transformations is often of interest. In this work, we introduce a generic framework for assessing metallurgical phase transformations, building on a previously-developed general simulation framework for predicting temperature evolution, distortions, and residual stresses. Experimental work was conducted to validate numerical predictions and included temperature measurements, EBSD/XRD microstructural examinations. Additional test data from the published literature was used to validate melt pool sizes and unfused powder predictions. We conclude that the continuum-level internal state variable approach proposed here can be calibrated with a reasonable amount of effort and can be used directly to link processing conditions to microstructural features. Upcoming work investigates the influence of microstructure features on mechanical performance to address the process-structure-property-performance relationship in SLM additive manufacturing.