The absolute abundance calibration project: the <i>Lycopodium</i> marker-grain method put to the test

Traditionally, dinoflagellate cyst concentrations are calculated by adding an exotic marker or “spike” (such as Lycopodium clavatum) to each sample following the method of Stockmarr (1971). According to Maher (1981), the total error is controlled mainly by the error on the count of Lycopodium clavatum spores. In general, the more L. clavatum spores counted, the lower the error. A dinocyst / L. clavatum spore ratio of ~2 will give optimal results in terms of precision and time spent on a sample. It has also been proven that the use of the aliquot method yields comparable results to the marker-grain method (de Vernal et al., 1987). Critical evaluation of the effect of different laboratory procedures on the marker grain concentration in each sample has never been executed. Although, it has been reported that different processing methods (e.g. ultrasonication, oxidizing, etc.) are to a certain extent damaging to microfossils (e.g. Hodgkinson, 1991), it is not clear how this is translated into concentration calculations. It is wellknown from the literature that concentration calculations of dinoflagellate cysts from different laboratories are hard to resolve into a consistent picture. The aim of this study is to remove these inconsistencies and to make recommendations for the use of a standardized methodology. Sediment surface samples from four different localities (North Sea, Celtic Sea, NW Africa and Benguela) were macerated in different laboratories each using its own palynological maceration technique. A fixed amount of Lycopodium clavatum tablets was added to each sample. The uses of different preparation methodologies (sieving, ultrasonicating, oxidizing …) are compared using both concentrations – calculated from Lycopodium tablets - and relative abundances (more destructive methods will increase the amount of resistant taxa). Additionally, this study focuses on some important taxonomic issues, since obvious interlaboratorial differences in nomenclature are recorded

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Electrospun polymethylacrylate nanofibers membranes for quasi-solid-state dye sensitized solar cells

Polymethylacrylate (PMA) nanofibers membranes are fabricated by electrospinning technique and applied to the polymer matrix in quasi-solid-state electrolytes for dye sensitized solar cells (DSSCs). There is no previous studies reporting the production of PMA nanofibers. The electrospinning parameters such as polymer concentration, applied voltage, feed rate, tip to collector distance and solvent were optimized. Electrospun PMA fibrous membrane with average fiber diameter of 350 nm was prepared from a 10 wt% solution of PMA in a mixture of acetone/N,N-dimethylacetamide (6:4 v/v) at an applied voltage of 20 kV. It was then activated by immersing it in 0.5 M LiI, 0.05 M I2, and 0.5 M 4-tert-butylpyridine in 3-methoxyproponitrile to obtain the corresponding membrane electrolyte with an ionic conductivity of 2.4 × 10−3 S cm−1 at 25 °C. Dye sensitized solar cells (DSSCs) employing the quasi solid-state electrolyte have an open-circuit voltage (Voc) of 0.65 V and a short circuit current (Jsc) of 6.5 mA cm−2 and photoelectric energy conversion efficiency (η) of 1.4% at an incident light intensity of 100 mW cm−2

Compatibility and epitaxial crystallization between poly(ethylene) and poly(ethylene)-like polyesters

This work describes the phase behavior of blends of 'polyethylene-like' polypentadecalactone (PPDL) and polyethylene. Blends of high-density polyethylene (HDPE) and PPDL were shown to be immiscible at the onset of crystallization of polyethylene, resulting in phase-separated morphologies. However, epitaxial crystallization of PPDL onto the HDPE crystals was observed by transmission electron microscopy (TEM), resulting in lamellae penetrating through the interface of the two polymers. Furthermore, PPDL/low-density polyethylene (LDPE) blends were produced and used for film extrusion, yielding clear films with good optical properties, despite the presence of fully phase-separated morphology. For PPDL-rich blends, TEM analysis revealed the formation of highly elongated crystalline domains of LDPE, from which the PPDL domains were epitaxially crystallized yielding a shish-kebab type of morphology. In these structures, the extended LDPE domains formed shishes with LDPE micro-kebabs, onto which PPDL macro-kebabs crystallized. The shish-kebab morphology was furthermore confirmed using x-ray analysis. The high aspect ratio of the LDPE domains is caused by the long relaxation times of LDPE in combination with the low interfacial tension between LDPE and PPDL. As a consequence of the lower relaxation time of PPDL (due to the linear chain architecture), the PPDL domains in the LDPE-rich blends have a lower aspect ratio. The strong epitaxial crystallization in combination with anisotropy in the morphology has a positive effect on the optical properties of the films

Superior Corrosion and UV-Resistant Highly Porous Poly(vinylidene fluoride- co-hexafluoropropylene)/alumina Superhydrophobic Coating

The current research is devoted to fabricating a superhydrophobic coating on alumina surfaces via a facile one-step electrospinning technique. The wettability properties of the as-prepared coating were investigated. The polymeric coatings exhibited a water contact angle (WCA) of about 152° ± 3 and a sliding angle (SA) is 4 ± 2°. However, a WCA of 154 ± 2° and a SA of 3 ± 2° were recorded after the addition of Al2O3 nanoparticles. The wettability of the prepared coatings has also been inspected after exposure to intense UV irradiation of 0.89 W/(m2 nm) and high-temperature degree of 60 °C, for 500 h. It was found that the measured WCA and water contact hysteresis (WCAH) for the poly(vinylidene fluoride-co-hexafluoropropylene) PVDF-HFP/Al2O3 nanocomposite 150 ± 1° and 10 ± 1° compared with 122 ± 4° and 22 ± 4° of pure PVDF-HFP, respectively. The morphology of the superhydrophobic coating was explored, illustrating the construction of a beaded fiber structure. The surface roughness of the fabricated super water-repellent coatings was recorded using an atomic force microscope (AFM). The electrochemical behavior of superhydrophobic coating was evaluated by electrochemical impedance spectroscopy (EIS) in 3.5 wt % NaCl solution before and after exposure to UV radiation. The research outcomes promote a one-step fabrication technique to prepare polymeric superhydrophobic coatings with good resistance for corrosion and degradation under UV irradiation

Multifunctional self-healing polymeric nanocomposite coatings for corrosion inhibition of steel

The present work focuses on the self-healing and corrosion behavior of novel epoxy based coatings containing epoxy monomer (EM) and dodecylamine (DDA) as self-healing and corrosion inhibitor, respectively. The coating self-healing ability and the corrosion inhibition effect have been combined, together, in one single coated layer providing autonomous corrosion protection. Towards this goal, the as-synthesized titania nanotubes (TNTs), with an average size of 20 nm were impregnated with DDA and EM and were thoroughly dispersed into the epoxy used as the matrix and applied on steel. Fourier-transform infrared spectroscopy (FTIR) analysis confirms the presence of DDA loaded nanotubes and the loading of inhibitor was estimated by thermogravimetric analysis. Additionally, the amount of the released corrosion inhibitor was identified by gas chromatography–mass spectrometry (GC–MS). The scanning electron microscopy (SEM), analysis shows the polymer healing of the prepared coatings when damaged. The electrochemical studies indicate that the corrosion rate of the steel samples coated with the epoxy modified with the healing additives decreases after 5 days of immersion in saline water.This publication was made possible by Grant # NPRP 9–080-2-039 from Qatar National Research Fund (a member of the Qatar Foundation). Statements made herein are solely the responsibility of the authors. R. A. Shakoor also acknowledges “QU internal grant-QUCGCAM-2018/2019-3” for this research work. M.F. Montemor would like to acknowledge Fundação para a Ciência e a Tecnologia for the CQE project UID/QUI/00100/2013.Scopu

Serum angiopoietin-2 as a noninvasive diagnostic marker of stages of liver fibrosis in chronic hepatitis C patients

Background The process of fibrogenesis is associated with the development of disease-specific markers. The management of chronic hepatitis C (CHC) depends on the staging of liver fibrosis. Use of noninvasive methods is preferable in diagnosis and follow-up. Objective The aim of this study is to evaluate serum angiopoietin-2 (Ang-2) as a noninvasive marker in the diagnosis of different stages of liver fibrosis in CHC patients. Materials and methods A total of 90 individuals were included. They were divided into a patient group (75 patients) and a control group (15 normal individuals). Serum Ang-2 was measured using enzyme-linked immunosorbent assay. Pretreatment liver biopsy was performed for the patients. The METAVIR score was used in the staging of liver fibrosis. A comparison of Ang-2 was performed between patients and controls, and between different stages of liver fibrosis. A receiver operating characteristic curve analysis was carried out to determine the best cutoff values of Ang-2 in the differentiation of different stages of fibrosis. Results Ang-2 serum levels were significantly higher in advanced stages of liver fibrosis. The cutoff points 869.3, 2226, and 7205 pg/ml were the best for differentiating fibrosis stages >F1; >F2; and >F3, respectively. Ang-2, international normalized ratio, α-fetoprotein, and albumin were found to be independent predictors of liver fibrosis using univariate analysis. Conclusion Ang-2 correlated significantly with liver fibrosis stage. It can aid noninvasive differentiation between different stages of liver fibrosis in patients with CHC