Ab Ratio Research Articles

Blood biomarkers for Alzheimer’s disease with the Lumipulse automated platform: Age-effect and clinical value interpretation

BackgroundAdvances in analytical methods have recently paved the way to Alzheimer’s disease (AD) biomarkers testing in blood along with the more established CSF testing. To ensure a forthcoming application of this low-invasive diagnostic that might allow to recognize early onset of dementia, appropriate pathological cut-points need to be defined. MethodsIn this cross-sectional study we measured blood and CSF neurofilament light chain (NFL), phosphorylated tau (pTau 181), Amyloid-β1-42 (AB 1–42) and Amyloid-β1-40 (AB 1–40) on a fully automated chemiluminescent platform (Lumipulse, Fujirebio) in 80 cognitively impaired patients and 55 cognitively unimpaired subjects. Clinical cut points were calculated with receiver-operator characteristic (ROC) curve analysis and a head-to-head comparison of blood and CSF testing was performed. ResultsBlood NFL best discriminant thresholds to distinguish neurodegenerative diseases from controls varied age-dependently, being 19 and 33 pg/mL in subjects 50–65 years and > 65 years respectively. AD was best framed by AB 1–42/1–40 ratio < 0.079 and ptau181 > 1 pg/mL. Though a strong correlation for all biomarkers, only blood AB ratio was equal to CSF testing for AD diagnosis. ConclusionsThe specific context of use might be considered to define the cut-offs of blood biomarkers of neurodegenerative diseases. Future efforts towards reference materials for each AD blood biomarker will improve clinical cut-offs.

Anti-tissue factor antibody conjugated with monomethyl auristatin E or deruxtecan in pancreatic cancer models.

Antibody-drug conjugates (ADCs) have been recognized as a promising class of cancer therapeutics. Tissue factor (TF), an initiator of the blood coagulation pathway, has been investigated regarding its relationship with cancer, and several preclinical and clinical studies have presented data on anti-TF ADCs, including tisotumab vedotin, which was approved in 2021. However, the feasibility of other payloads in the design of anti-TF ADCs is still unclear because no reports have compared payloads with different cytotoxic mechanisms. For ADCs targeting other antigens, such as Her2, optimizing the payload is also an important issue in order to improve invivo efficacy. In this study, we prepared humanized anti-TF Ab (clone.1084) conjugated with monomethyl auristatin E (MMAE) or deruxtecan (DXd), and evaluated the efficacy in several cell line- and patient-derived xenograft models of pancreatic cancer. As a result, optimizing the drug / Ab ratio was necessary for each payload in order to prevent pharmacokinetic deterioration and maximize delivery efficiency. In addition, MMAE-conjugated anti-TF ADC showed higher antitumor effects in tumors with strong and homogeneous TF expression, while DXd-conjugated anti-TF ADC was more effective in tumors with weak and heterogeneous TF expression. Analysis of a pancreatic cancer tissue array showed weak and heterogeneous TF expression in most TF-positive specimens, indicating that the response rate to pancreatic cancer might be higher for DXd- than MMAE-conjugated anti-TF ADC. Nevertheless, our findings indicated that optimizing the ADC payloads individually in each patient could maximize the potential of ADC therapeutics.

CIELAB Color Space as a Field for Tracking Color-Changing Chemical Reactions of Polymeric pH Indicators.

Two types of cross-linked polymeric dye films that exhibit reversible color changes in response to pH were prepared. Upon protonation, films with a nitrophenol dye moiety (NP) changed from yellow to colorless, whereas films with an azobenzene dye moiety (AB) changed from yellow to reddish-purple. The colored light transmitted through these films from a D65 white-light source was measured colorimetrically, and the transition of the chromaticity point in CIELAB upon protonation of the polymeric dyes was observed. At low dye concentrations ([NP] < 4.7 × 10-5 and [AB] < 2.7 × 10-5 mol L-1), linear loci of the chromaticity points were displayed for both polymeric dye films, indicating perceptual linearity. This linearity is caused by the avoidance of nonlinear perceptual phenomena such as the Abney effect and the Bezold-Brücke phenomenon. The perceptual linearity of space is a necessary condition for achieving stoichiometric linearity, which requires an additional linear relationship between the dye concentration and each component, a*, b*, and L*. A geometric equation that included the AB concentration and the protonation ratio of AB was used to successfully depict, on the basis of stoichiometric linearity, the protonation of the polymeric AB films three-dimensionally in the restricted area of CIELAB.

The Effect of Block Ratio and Structure on the Thermosensitivity of Double and Triple Betaine Block Copolymers.

AB-type and BAB-type betaine block copolymers composed of a carboxybetaine methacrylate and a sulfobetaine methacrylate, PGLBT-b-PSPE and PSPE-b-PGLBT-b-PSPE, respectively, were synthesized by one-pot RAFT polymerization. By optimizing the concentration of the monomer, initiator, and chain transfer agent, block extension with precise ratio control was enabled and a full conversion (~99%) of betaine monomers was achieved at each step. Two sets (total degree of polymerization: ~300 and ~600) of diblock copolymers having four different PGLBT:PSPE ratios were prepared to compare the influence of block ratio and molecular weight on the temperature-responsive behavior in aqueous solution. A turbidimetry and dynamic light scattering study revealed a shift to higher temperatures of the cloud point and micelle formation by increasing the ratio of PSPE, which exhibit upper critical solution temperature (UCST) behavior. PSPE-dominant diblocks created spherical micelles stabilized by PGLBT motifs, and the transition behavior diminished by decreasing the PSPE ratio. No particular change was found in the diblocks that had an identical AB ratio. This trend reappeared in the other set whose entire molecular weight approximately doubled, and each transition point was not recognizably impacted by the total molecular weight. For triblocks, the PSPE double ends provided a higher probability of interchain attractions and resulted in a more turbid solution at higher temperatures, compared to the diblocks which had similar block ratios and molecular weights. The intermediates assumed as network-like soft aggregates eventually rearranged to monodisperse flowerlike micelles. It is expected that the method for obtaining well-defined betaine block copolymers, as well as the relationship of the block ratio and the chain conformation to the temperature-responsive behavior, will be helpful for designing betaine-based polymeric applications.

Assessing the associations between plasma C reactive protein, Ab 42/40 ratio, global amyloid and entorhinal tau PET

AbstractBackgroundLower plasma ratio of amyloid beta (Ab42/Ab40) has been associated with brain amyloid, however, the mechanistic link is unclear. Systemic inflammation may contribute to plasma Ab levels and promote or reduce the accumulation of Alzheimer’s disease (AD) neuropathology. C reactive protein (CRP) is an inflammatory marker implicated in amyloidosis. Using a cross sectional analysis, we evaluated the relationship between blood levels of CRP and Ab ratio, global amyloid positron emission tomography (PET), and tau PET in the entorhinal cortex where tau accumulates early. We hypothesized that Ab positivity would modify the relationship between CRP and AD pathology.MethodIn 969 cognitively normal participants (age: 50‐87, 781 Ab‐/188 Ab+) (Table 1) from the Health and Aging Brain Study‐ Health Disparities (HABS‐HD), we acquired 18F‐PI‐2620 tau‐PET, florbetaben amyloid PET scans, and plasma measures of Ab 42/40 and CRP. Subjects were categorized by Ab + or Ab ‐ by a global amyloid PET standardized uptake value ratio (SUVR) cutoff of 1.08. Within Ab groups, we performed multiple regressions to evaluate associations between 1) global amyloid and entorhinal tau‐PET SUVRs and 2) plasma markers of Ab ratio and CRP. We covaried for age, gender, education, APOE4, and scanner and used false discovery rate (FDR) for multiple comparison corrections.ResultIn Ab+ participants, higher amyloid (b = ‐0.31, p = 0.0005) and tau PET (b = ‐0.36, p = 0.004) were significantly associated with low Ab ratio, but not in Ab‐ for amyloid or tau, with significant interactions by Ab positivity for amyloid (b = ‐0.45, p = 2.65×10−6) and tau (b = ‐0.77, p = 0.0002) (Figure 1). In Ab+ participants, higher CRP was associated with higher Ab ratio (b = 0.21, p = 0.04) and a trend toward lower amyloid (b = ‐0.15, p = 0.084) and tau PET (b = ‐0.22, p = 0.084), but not in Ab‐ participants, with a significant interaction by Ab positivity for Ab ratio (b = 0.46, p = 0.011) (Figure 2) and amyloid (b = ‐0.11, p = 0.0006) and tau PET (b = ‐0.17, p = 0.016).ConclusionIn cognitively intact Ab+ but not Ab‐ adults, higher plasma Ab ratio was associated with lower global amyloid and entorhinal tau PET. In Ab+ participants, higher CRP was associated with blood and brain amyloid and tau levels consistent with less AD pathology.

Synthesis of Site-Specific Antibody-[60]Fullerene-Oligonucleotide Conjugates for Cellular Targeting.

An ideal therapeutic antibody-oligonucleotide conjugate (AOC) would be a uniform construct, contain a maximal oligonucleotide (ON) payload, and retain the antibody (Ab)-mediated binding properties, which leads to an efficient delivery of the ON cargo to the site of therapeutic action. Herein, [60]fullerene-based molecular spherical nucleic acids (MSNAs) have been site-specifically conjugated to antibodies (Abs), and the Ab-mediated cellular targeting of the MSNA-Ab conjugates has been studied. A well-established glycan engineering technology and robust orthogonal click chemistries yielded the desired uniform MSNA-Ab conjugates (MW ∼ 270 kDa), with an oligonucleotide (ON):Ab ratio of 24:1, in 20-26% isolated yields. These AOCs retained the antigen binding properties (Trastuzumab's binding to human epidermal growth factor receptor 2, HER2), studied by biolayer interferometry. In addition, Ab-mediated endocytosis was demonstrated with live-cell fluorescence and phase-contrast microscopy on BT-474 breast carcinoma cells, overexpressing HER2. The effect on cell proliferation was analyzed by label-free live-cell time-lapse imaging.

A chemiluminescent magnetic microparticle immunoassay for the detection of antibody against African swine fever virus.

The p30 protein is abundantly expressed in the early stage of African swine fever virus (ASFV) infection. Thus, it is an ideal antigen candidate for serodiagnosis with the use of an immunoassay. In this study, a chemiluminescent magnetic microparticle immunoassay (CMIA) was developed for the detection of antibodies (Abs) against ASFV p30 protein in porcine serum. Purified p30 protein was coupled to magnetic beads, and the experimental conditions including concentration, temperature, incubation time, dilution ratio, buffers, and other relevant variables were evaluated and optimized. To evaluate the performance of the assay, a total of 178 pig serum samples (117 negative and 61 positive samples) were tested. According to receiver operator characteristic curve analysis, the cut-off value of the CMIA was 104,315 (area under the curve, 0.998; Youden's index, 0.974; 95% confidence interval: 99.45 to 100%). Sensitivity results showed that the dilution ratio of p30 Abs in ASFV-positive sera detected by the CMIA is much higher when compared to commercial blocking ELISA kit. Specificity testing showed that no cross-reactivity was observed with sera positive for other porcine disease viruses. The intraassay coefficient of variation (CV) was < 5%, and the interassay CV was < 10%. The p30-magnetic beads could be stored at 4 °C for more than 15 months without loss of activity. The kappa coefficient between CMIA and INGENASA blocking ELISA kit was 0.946, showing strong agreement. In conclusion, our method showed superiority with high sensitivity, specificity, reproducibility, and stability and potentialized its application in the development of a diagnostic kit for the detection of ASF in clinical samples. KEY POINTS: • ASFV tag-free p30 was successfully purified. • High sensitivity, specificity, relatively simple, and time-saving to detect antibody against ASFV were developed. • The development of CMIA will help the clinical diagnosis of ASFV and will be useful for large-scale serological test.

The effect of Acacia nilotica bark extract on growth performance, carcass characteristics, immune response, and intestinal morphology in broilers as an alternative to antibiotic growth promoter.

Present study was designed to evaluate the efficacy of Acacia nilotica bark extract as an alternative to antibiotic growth promoters in broilers. Six hundred, day-old broiler chicks were randomly divided into six groups (NC, without any supplementation; AB, NC+Zinc Bacitracin; PB, NC+Safmannan; ANBE1, NC+A. nilotica bark extract 0.1%; ANBE3, NC+A. nilotica bark extract 0.3%; ANBE5, NC+A. nilotica bark extract 0.5%), with ten replicates per group (10 chicks/replicate) and feeding trial was lasted for 35 days. Results showed that weight gain (1,296.63 g) and feed conversion ratio (FCR, 1.59) of AB was better than NC, during the finisher phase. Overall FCR of AB (1.53), PB (1.54), and ANBE5 (1.54) was significantly (p<0.05) better than NC. From carcass parameters relative weight of wing and heart were highest in ANBE3 (2.5% and 1.51%, respectively). Significantly (p<0.05) highest blood glucose level was observed in NC (264.5 mg/dL) and highest albumin concentration was found in AB (1.46 mg/dL). In addition, antibody titer levels against ND and IBD were higher in ANBE5 than NC, while higher relative weight of bursa was observed in ANBE3 than NC. The villus height to crypt depth ratio in all experimental groups was better than NC. Acacia nilotica bark extract could be a suitable alternative to antibiotic growth promoters to support the growth in broilers.

Linking trait network to growth performance of submerged macrophytes in response to ammonium pulse

Extreme precipitation events caused by climate change leads to large variation of nitrogen input to aquatic ecosystems. Our previous study demonstrated the significant effect of different ammonium pulse patterns (differing in magnitude and frequency) on submersed macrophyte growth based on six plant morphological traits. However, how connectivity among plant traits responds to nitrogen pulse changes, which in turn affects plant performance, has not yet been fully elucidated. The response of three common submersed macrophytes (Myriophyllum spicatum, Vallisneria natans and Potamogeton maackianus) to three ammonium pulse patterns was tested using plant trait network (PTN) analysis based on 18 measured physiological and morphological traits. We found that ammonium pulses enhanced trait connectivity in PTN, which may enable plants to assimilate ammonium and/or mitigate ammonium toxicity. Large input pulses with low frequency had stronger effects on PTNs compared to low input pulses with high frequency. Due to the cumulative and time-lagged effect of the plant response to the ammonium pulse, there was a profound and prolonged effect on plant performance after the release of the pulse. The highly connected traits in PTN were those related to biomass allocation (e.g., plant biomass, stem ratio, leaf ratio and ramet number) rather than physiological traits, while phenotype-related traits (e.g., plant height, root length and AB ratio) and energy storage-related traits (e.g., stem starch) were least connected. V. natans showed clear functional divergence among traits, making it more flexible to cope with unfavorable habitats (i.e., high input pulses with low frequencies). M. spicatum with high RGR revealed strong correlations among traits and thus supported nitrogen accumulation from favourable environments (i.e., low input pulses with high frequencies). Our study highlights the responses of PTN for submerged macrophytes to ammonium pulses depends on their intrinsic metabolic rates, the magnitude, frequency and duration of the pulses, and our results contribute to the understanding of the impact of resource pulses on the population dynamics of submersed macrophytes within the context of global climate change.

Variation in biochemical, physiological and ecophysiological traits among the teak (Tectona grandis Linn. f) seed sources of India

Teak being an iconic timber species the studies on its physiological and biochemical traits are very limited in India and worldwide. As a result, the current study aimed to assess biochemical parameters such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, chlorophyll ab ratio, proline content, and peroxidase activity, along with physiological parameters such as Chlorophyll stability index, relative water content, and leaf area, as well as ecophysiological traits such as net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), Leaf temperature, intrinsic water-use efficiency (iWUE), instantaneous water use efficiency and intrinsic carboxylation efficiency of thirty teak seed sources collected from different states of India. FCRITK 19, FCRITK 21, FCRITK 25, FCRITK 29, and FCRITK 05 were reported to have a greater photosynthetic rate (> 17 µmol m−2 s−1) coupled with a relative water content of more than 50% and a chlorophyll stability index of more than 60%, which could be used in a future genetic improvement programme. Correlation analysis indicated that water use efficiency was found to be strongly but negatively correlated with transpiration rate (−0.601) and stomatal conductance (−0.910). The proline content had a substantial positive correlation with the chlorophyll stability index (0.890), signifying that they are associated with abiotic stress conditions. Cluster analysis was attempted to discriminate the sources based on biochemical, physiological and ecophysiological traits. Eleven sources (FCRITK 25, FCRITK 27, FCRITK 29, FCRITK 14, FCRITK 30, FCRITK 16, FCRITK 05, FCRITK 13, FCRITK 02, FCRITK 17 and FCRITK 15) exhibited superior performance compared to rest of the sources.

Association between Opisthorchis viverrini Infection and Glomerular Disease in Thailand

Introduction: Opisthorchis viverrini (OV) is a major cause of infection in Southeast Asia. Previous studies in mouse models have shown that OV infection can contribute to immune-complex glomerulonephritis (GN). However, OV infection in human kidney tissue has never been demonstrated. Herein, we evaluated the association of OV infection with biopsy-proven glomerular disease. Methods: This study was performed in adult patients who underwent kidney biopsy between July 2016 and February 2017. All kidney tissue samples were processed using the standard techniques for renal pathological diagnoses and immunohistochemistry techniques to detect OV antigen. Pre-implanted donor kidney tissue samples were used as controls. The participants were also assessed for OV infection by serum OV immunoglobulin G antibody (Ab) levels and/or presence of OV eggs in stool. Results: Forty-three renal tissue samples from glomerular disease patients and 50 from transplant donors were included in the study. Mean age in the GN group was 41.7 ± 15.9 years, estimated glomerular filtration rate (eGFR) was 70.65 ± 36.61 mL/min/1.73 m², and median proteinuria was 3.17 (1.70–4.95) g/day. Lupus nephritis (LN) was the most common diagnosis (32.6%), followed by IgA nephropathy (23.3%), IgM nephropathy (18.6%), and primary membranous nephropathy (MN; 7%). The OV antigen was observed in kidney tissue from patients with IgA nephropathy, LN, primary MN, focal segmental glomerulosclerosis, and IgM nephropathy. By contrast, no OV antigen was detected in tissue samples from the control group. The presence of OV antigens was observed in glomerular endothelial cells, mesangial cells, tubular cells, and peritubular capillaries. The odds ratio of positive serum OV Ab to predict the presence of OV antigen in kidney tissues was 4.47 (p = 0.057), and there was a negative correlation between levels of serum OV Ab and eGFR (r = −0.31, p = 0.04). Discussion/Conclusion: This is the first study to demonstrate the presence of OV antigen in human kidney tissue, which indicates that OV infection may be associated with biopsy-proven glomerular diseases.

Immune Responses to SARS CoV-2: A Scoping Review

COVID-19 is noxious and constitutes a raft of adverse multiplier effects. As such, there is urgent need to understand the disease well and take action to mitigate its punitive pathologic &amp; economic outcomes. Comprehending the conduct of the immune system during and after infection may provide fundamental leads to unraveling effective interventions. Some vaccines and drugs have since been validated and made available for emergency use among priority populations. However, these vaccines were developed at an accelerated pace and mainly on the basis of rudimentary immunological &amp; molecular events. Therefore, there is need for continuous revelation of precise and more elaborate hallmarks in order to improve on, or develop more efficacious and safe interventions. Three scientific databases (PubMed, Cochrane and EMBASE) were searched between 1st December, 2020 and 15th January, 2021 for information about immune responses to SARS COV-2. Studies that utilized experimental designs, exhibited little to no likelihood of bias, published in highly refereed and peer reviewed journals were selected. A total of 10 papers were shortlisted for the final synthesis. A set of cytokines including: IL-2, IL-6, IL-7, IL-10, TNF, and GM-CSF are recovered in most cases. However, IL-6 is featured in most severe and fatal events. There wasn’t congruency by different studies on the precise conduct of T-cells during infection. Some studies reported elevated levels of both CD+4 &amp; CD+8 T-cells among severe cases while others reported exhausted elevated levels of the same immunological parameters during mild disease. Higher levels of Natural Killer-cells (NK-cells) as well as Neutralizing Antibodies (Nabs) correlate with better disease outcomes. However, considering the role played by Abs in the production of cytokines (pro and anti-inflammatory), it may be crucial to profile the risk/benefit ratio of Abs during infection. Interventions that seek to: reverse high production of pro-inflammatory cytokines (IL-6), potentiate release and function of NK-cells, as well as Nabs and moderate exhaustion of CD+4 &amp; CD+8 T-cells, may constitute promising outcomes.

Wave Dissipation by Bottom Friction on the Inner Shelf of a Rocky Shore

AbstractApproximately 32% of the measured wave energy flux by sea and swell waves was dissipated over distances less than 130 m, outside of wave breaking on the inner shelf, over a rocky shore in southern Monterey Bay, CA. The bottom roughness of the rocky shore is defined by the standard deviation of bottom vertical variability, σb, that is 0.9 m, which is of similar magnitude to previously measured σb for rough coral reefs. Spectral wave energy flux balanced by bottom friction is modeled and compared with observations. Measured average wave reflection was 0.08 and is neglected in the model. The average energy dissipation owing to bottom friction over the rocky shore results in energy friction factors, fe, ranging 4 to 34. The observed fe are larger than previously measured fe on coral reefs. An empirical power law relationship is developed for fe as a function of the ratio of wave orbital excursion amplitude, Ab, and σb, based on combined data from coral reefs, rocky platforms, and this rocky shore. As σb increases, fe increases. Numerical simulation by Yu et al. (2018, https://doi.org/10.9753/icce.v36.waves.57) of waves over large bottom variations, similar to observed on coral reefs, suggests that drag forces do not account for the large observed fe. Therefore, it is hypothesized that bottom friction on rocky shores is a function of multiscale physical and biological roughness.

Evacuated tube heat pipe solar collector for Encontech engine‐driven reverse osmosis solar desalination

Utilization of a single evacuated tube heat pipe solar collector (ETHPSC) for the efficient deployment of the solar energy toward driving the Encontech heat engine for reverse osmosis desalination is considered in this study. The effects of the mass flow rate of water , inlet temperature (T i), solar intensity (I), the ratio of the condenser to absorber area (A co/A abs), heat transfer coefficients ( h air and h vacuum) on energy and exergy efficiency (η, η Ex), the absorber ( T abs), condenser ( T co), and the outlet temperature ( T o) are explored by using a heat transfer resistance model. An open-source SCILAB software was used for performing the computer simulations. The simulation results show that for each h air there is an optimum T i (based on the exergetic performance). The lower h air and h vacuum appears to be more promising to improve the efficiency and temperature gain ( T i − T o) of the ETHPSC. The maximum energetic efficiency of 52.5% is obtained for h vacuum (1 W/m2 K). Obtained results further demonstrate that the energetic and exergetic performances of the ETHPSC are higher at T i = 50°C. Both energetic and exergetic efficiencies exhibit upper values at A co/A abs ratio up to 1. Further increment in this ratio up to 3 resulted in a decrease in the efficiency of the ETHPSC.

Delayed dosing intervals for quadrivalent human papillomavirus vaccine do not reduce antibody avidity

ABSTRACT The quadrivalent HPV vaccine (4vHPV) was originally recommended as a three-dose series (0/2/6 months), though delays in completing the series frequently occur. We previously found delayed dosing in girls resulted in similar or higher antibody titers compared to on-time dosing. Archived sera from 262 healthy females aged 9–18 recruited from pediatric clinics were tested to determine if delayed dosing intervals affected antibody avidity. Avidity index (AI; ratio of IgG Ab bound in the treated and untreated sample) was determined pre- and post-dose 3 4vHPV for each participant using a modified multiplex ELISA. Data were grouped by dosing intervals: (1) on-time dose 2 and 3, (2) delayed dose 2 and on-time dose 3, (3) on-time dose 2 and delayed dose 3, (4) delayed dose 2 and 3. Overall, mean AI was highest for HPV16 and lowest for HPV6. As expected, AI did not differ between groups 1 & 3 or groups 2 & 4 pre-dose 3, however, for most types mean AI was significantly higher both pre- and post-dose 3 for groups with delayed dose 2. For all types, mean AI was higher post-dose 3 in all delayed dosing groups compared to group 1. One month post-dose 3, there was a positive but weak correlation between AIs and antibody titer for HPV 6 (ρ = 0.25, p = .0001), HPV 11 (ρ = 0.14, p = .0370), HPV 16 (ρ = 0.11, p = .0934), and HPV 18 (ρ = 0.37, p < .0001). Our findings suggest longer intervals between doses result in higher antibody avidity, providing further evidence that delayed dosing of 4vHPV does not hinder the immune response.

Facile preparation of BCN nanofibers with tunable band gaps

As a new synthetic metal-free material, BCN has aroused great interests in the field of photocatalyst materials due to its lower cost as well as higher reliability and better sustainability. In this work, we prepared BCN nanofibers by electrospinning of precursor solution containing polyacrylonitrile and ammonia borane, and then pyrolyzed the polymer fibers in NH3. Infrared spectroscopy (FT-IR), Scanning emission microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to analyse the composition and structure of the samples. The results show that the BCN nanofibers have an average diameter of 50-100 nm and mainly compose of BN nanocrystals. C atoms are distributed at the BN grain boundary in terms of B-C and B-N bonds. The band gap of the fibers is between 2.1-2.7 eV and can be adjusted by changing the ratio of PAN and AB in the raw materials.

Application of different plasticity models to PC/ABS blends within micromechanical approaches

AbstractRubber‐toughened thermoplastic polymers such as PC/ABS blends exhibit a non‐monotonic dependence of fracture toughness on composition, e.g. [6]. The key parameters determining the mechanical response of PC/ABS are the PC vs. ABS ratio and the rubber content in ABS. In this contribution, two micromechanical modeling approaches (single particle unit cell models, random representative volume elements) are considered to investigate this behavior. Thereby, different visco‐plasticity models are utilized to capture the specific deformation behavior of each phase. Computational studies of both micromechanical modeling approaches are compared to each other as well as to experimental data.

A review of methods for quantifying spatial predator–prey overlap

AbstractBackgroundStudies that attempt to measure shifts in species distributions often consider a single species in isolation. However, understanding changes in spatial overlap between predators and their prey might provide deeper insight into how species redistribution affects food web dynamics.Predator–prey overlap metricsHere, we review a suite of 10 metrics [range overlap, area overlap, the local index of collocation (Pianka's O), Hurlbert's index, biomass‐weighted overlap, asymmetrical alpha, Schoener's D, Bhattacharyya's coefficient, the global index of collocation and the AB ratio] that describe how two species overlap in space, using concepts such as binary co‐occurrence, encounter rates, spatial niche similarity, spatial independence, geographical similarity and trophic transfer. We describe the specific ecological insights that can be gained using each overlap metric, in order to determine which is most appropriate for describing spatial predator–prey interactions for different applications.Simulation and case studyWe use simulated predator and prey distributions to demonstrate how the 10 metrics respond to variation in three types of predator–prey interactions: changing spatial overlap between predator and prey, changing predator population size and changing patterns of predator aggregation in response to prey density. We also apply these overlap metrics to a case study of a predatory fish (arrowtooth flounder, Atheresthes stomias) and its prey (juvenile walleye pollock, Gadus chalcogrammus) in the Eastern Bering Sea, AK, USA. We show how the metrics can be applied to understand spatial and temporal variation in the overlap of species distributions in this rapidly changing Arctic ecosystem.ConclusionsUsing both simulated and empirical data, we provide a roadmap for ecologists and other practitioners to select overlap metrics to describe particular aspects of spatial predator–prey interactions. We outline a range of research and management applications for which each metric may be suited.

Quantitative Assessment of Individual Populations Present in Nanoparticle-Antibody Conjugate Mixtures Using AF4-ICP-MS/MS.

A current remaining challenge in nanotechnology is the fast and reliable determination of the ratios between engineered nanoparticles and the species attached to their surface after chemical functionalization. The approach proposed herein based on the online coupling of asymmetric flow field-flow fractionation (AF4) with inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS) allows for the first time the direct determination of such ratios in CdSe/ZnS core-shell quantum dot:rat monoclonal IgG2a antibody (QD:Ab) conjugate mixtures in a single run without any previous sample preparation (i.e., derivatization). AF4 provides full recovery and adequate resolution of the resulting bioconjugate from the excess of nanoparticles and proteins used in the different bioconjugation mixtures (1:1, 2:1, and 3:1 QD:Ab molar ratios were assessed). The point-by-point determination by ICP-MS/MS of the metal to sulfur ratios along the bioconjugate fractographic peak allowed disclosing the mixture of the different species in the bioconjugated sample, providing not only the limits of the range of QD:Ab ratios in the different bioconjugate species resulting after functionalization but also a good estimation of their individual relative abundance in the mixture. Interestingly, a wide variety of compositions were observed for the different bioconjugate mixtures studied (QD:Ab molar ratios ranging from 0.27 to 4.6). The resulting weighted QD:Ab ratio computed in this way for each bioconjugate peak matches well with both the global (average) QD:Ab ratio experimentally obtained by the simpler peak area ratio computation and the theoretical QD:Ab molar ratios assayed, which internally validates the procedure developed.

Simultaneous umbilical blood flow during normal pregnancy in sheep and goat foetuses using non-invasive colour Doppler ultrasound.

The characteristics of umbilical blood flow (UM) was investigated using 18 (25 foetuses) pregnant ewes and 20 (41 foetus) pregnant goats transrectal non-invasive color Doppler ultrasonographic examinations were done frequently between 2 and 8 week after breeding and then transabdominally until parturition. Colour Doppler velocimetery includes blood flow volume (BFV), time averaged maximum velocity (TAMV), resistance index (RI), pulsatility index (PI), time average of mean (TAMEAN) and impedance of blood flow (PS/ED or AB ratio). Also a qualitative evaluation of UM blood flow indicating increases (P < 0.001) in BFV, TAMV and TAMEAN were observed until 19 week of pregnancy in foetuses of sheep and goats and then those values decreased (P < 0.001) from 19 week until parturition. Conversely, UM-PI, RI and PS/ED decreased (P < 0.002-0.01) until 19 week and then increased (P < 0.01-0.0001). The umbilical artery BFV increased (P < 0.0001) during pregnancy from 7.27 ± 0.82 ml/min in sheep vs. 4.96 ± 0.54 ml/min in goats at 6 week of gestation to 700.51 ± 31.05 ml/min (~100 fold) in sheep vs. 665.56 ± 48.22 ml/min (~133 fold) in goats at 19 week and then decreased (P < 0.0001) to 350.561 ± 72.15 ml/min in sheep vs. 215.17 ± 35.06 ml/min in goats at 20 week. The absence of end diastolic velocity (EDV) of umbilical artery blood flow was detected in both species between 4 and 12 week of pregnancy. Results of this study clearly show that the non-invasive colour Doppler sonography can be used successfully to assess umbilical blood flow in foetuses of pregnant sheep and goats. These may provide guidelines for assessing the state of intrauterine fetal growth retardation in pregnancies of sheep and goats.