Plasma-induced PAA-ZnO coated PVDF membrane for oily wastewater treatment: Preparation, optimization, and characterization through Taguchi OA design and synchrotron-based X-ray analysis

A novel membrane surface modification approach was proposed to successfully obtain a poly(vinylidene fluoride)-poly(acrylic acid)-ZnO (PVDF-PAA-ZnO) membrane with super-high water permeability and great oil rejection through cold plasma-induced PAA graft-polymerization followed by simple nano-ZnO self-assembly. The experimental parameters of modification were optimized and their optimal combination was identified using Taguchi orthogonal array (OA) design method. The PVDF-PAA-ZnO membrane was comprehensively characterized and the mechanism of nano-ZnO self-assembly was explored by contact angle measurement, scanning electron microscope (SEM) images, elemental analysis, tension test, Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and synchrotron-based X-ray analyses. It was revealed that ZnO nanoparticles were immobilized onto membrane surface through the adsorption of PAA layer to form a PAA-ZnO coating without valence change. The carboxyl groups of PAA layer provided complexing ligands to coordinate with Zn2+ and form bidentate species on the nano-ZnO surface. The firm PAA-ZnO coating on PVDF membrane surface converted its hydrophobic nature to hydrophilic, bringing about the dramatically improvement of membrane performance both in water permeation flux and oil rejection rate. The permeation flux of the PVDF-PAA-ZnO membrane was more than 10 times as great as that of the pristine PVDF membrane

AN EVALUATION OF THE POOLED LOLLI-METHOD RT-qPCR TESTING FOR COVID-19 SURVEILLANCE IN SINGAPORE

Background: Following the success of the Lolli-Method or Lolli-Test as a surveillance method in Germany, the Ministry of Health, Singapore investigated the feasibility of deploying the method as a rostered routine testing in vulnerable individuals such as children, nursing homes and frontline workers; and evaluated the sensitivity and ideal pooling ratio of the Lolli-Method.  Methods: The study was conducted in two phases – the first phase was to assess the operational feasibility of the Lolli-Method. It was held in conjunction with air sampling at a childcare centre with children ages 2 to 6 years old across 40 days. The second phase was to evaluate the sensitivity of the Lolli-Method with different pooling ratios and was conducted in collaboration with the National Centre for Infectious Diseases (NCID) where each pool was spiked with one Lolli swab from a COVID-positive patient. All patients enrolled in this study have their viral load cycle threshold (CT) levels assessed prior to admission via a mid-turbinate oropharyngeal (MTOP) polymerase chain reaction (PCR) swab.  Results: The sensitivity of the pooled Lolli-Test was similar to antigen rapid tests with 100% sensitivity (3/3) in a pooling ratio of 20:1 for patients with viral loads of cycle threshold (CT) levels below 20. For individuals with lower viral loads, the sensitivity of the Lolli-Test was 66.7% (2/3) in a pooling ratio of 20:1 and 100% (2/2) in a smaller pooling ratio of 15:1. The operational feasibility of the Lolli-Test was assessed to be high amongst study participants although students were noted to require some additional assistance from teachers.  Conclusion: The Lolli-Test is an effective surveillance method with adequate sensitivity to detect a COVID-19 infected individual in a pool of up to 20 albeit largely dependent on the viral load. Furthermore, the Lolli-Test also provides a less invasive alternative sample collection method for individuals who cannot tolerate or have contraindications for the regular nasal or oropharyngeal swabs such as young children. More studies should be done to assess the Lolli-Test’s true limit of detection and to evaluate the use of the Lolli-Method in infants and for other respiratory diseases such as influenza

Particle Size Effect On Load Transfer In Single Particle Composite Samples Via X-Ray Difiraction

Particulate composites are widely used in many aerospace applications including protective coatings, adhesives, or structures, and their mechanical properties and behavior have gained increasing significance. The addition of modifiers such as alumina generally leads to improved mechanical properties. In this work, samples with an isolated alumina particle embedded in an epoxy matrix were created to replicate the ideal assumptions for many particulate mechanics models. The effect of particle size on load transfer is determined here using a unique X-Ray Difiraction experimental set-up at the Canadian Light Source. At the Very Sensitive Elemental and Structural Probe Employing Radiation from a Synchrotron (VESPERS) beamline, a custom miniature mechanical load frame was used to apply compressive loads to each sample. At three different compressive loads, the alumina within each sample was exposed to a hard X-ray beam which created a difiraction pattern that was collected by a 2-D detector. A trend of increasing load transfer with increasing particle size was observed during the analysis of the difiraction rings. Results from this work provide experimental insight into the effect of particle size on load transfer in single particle composites and can serve to experimentally validate the theoretical load transfer models that currently exist

Site Energy Distribution and X‑ray Analyses of Nickel Loaded on Heterogeneous Adsorbents

The approximate site energy distributions were estimated to describe the adsorption of nickel ions on the heterogeneous surfaces of barley straw adsorbents based on the Langmuir–Freundlich model. The average site energy and standard deviation of the site energy distributions of the adsorbents were determined to analyze the interaction between the adsorbents and adsorbate, and the adsorption site heterogeneity. With higher site energy, the pretreated barley straw (PBS) has higher nickel adsorption capacity (59.5 mg/g) than most of the reported adsorbents. The bonding of nickel on PBS was investigated by X-ray absorption spectroscopies. X-ray absorption near edge structure results indicated that the nickel adsorbed on PBS remained as Ni­(II). Extended X-ray absorption fine structure data indicated that the adsorbed Ni was bonded to 6 oxygen atoms of carboxyl groups and/or water molecules. The results and methodology in this work are transferable to investigate other adsorption systems for separation applications

Enhancement of the Stability of Biosorbents for Metal-Ion Adsorption

Biosorbents have demonstrated great potential in the treatment of metal-containing wastewater. However, one of the bottleneck issues of using biosorbents is that amounts of organic carbon release from biosorbents into water. This seriously limits the application of biosorption technology in treating wastewater. In this work, a novel methodology was developed to greatly reduce the organic carbon release and enhance the stability of biosorbents by using barley straw as the model biosorbent material and nickel as the model metal ion. The raw barley straw was first made into cylindrical pellets, which were coated with a sodium alginate (SA) and poly­(vinyl alcohol) (PVA) membrane. The coating conditions including the ratio of SA to PVA, glutaraldehyde (GA) dose, concentration of CaCl₂ solution, and cross-linking time were optimized by L₉(3⁴) orthogonal array design. The pellets coated at the optimal conditions (1:1 mass ratio of SA to PVA, 1.0 mL of GA, 8% CaCl₂, and 20 min of cross-linking time) were then applied for nickel adsorption. The effects of the solution pH and ionic strength on the adsorption equilibrium and desorption of adsorbed nickel ions were investigated. Scanning electron microscopy and synchrotron X-ray fluorescence spectroscopy were used to locate the adsorption sites on the coated pellets. The results demonstrated that organic carbon release of the coated pellets was significantly reduced to 3.8–9.7 mg/g of dry barley straw pellets in the nickel adsorption process, while that of the raw barley straw particles was 44 mg/g. The nickel uptake increased to 25.6 mg/g, higher than that of the raw barley straw particles

Insights into Biochemical Alteration in Cancer-Associated Fibroblasts by using Novel Correlative Spectroscopy

The microenvironment of a tumor changes chemically and morphologically during cancer progression. Cancer-stimulated fibroblasts promote tumor growth, however, the mechanism of the transition to a cancer-stimulated fibroblast remains elusive. Here, the multi-modal spectroscopic methods Fourier transform infrared imaging (FTIRI), X-ray absorption spectroscopy (XAS) and X-ray fluorescence imaging (XFI) are used to characterize molecular and atomic alterations that occur in cancerstimulated fibroblasts. In addition to chemical changes in lipids (olefinic and acyl chain) and protein aggregation observed with FTIRI, a new infrared biomarker for oxidative stress in stimulated fibroblasts is reported. Oxidative stress is observed to cause lipid peroxidation, which leads to the appearance of a new band at 1721 cm(-1), assigned to 4-hydroxynonenal. Complementary to FTIRI, XFI is well suited to determining atom concentrations and XAS can reveal the speciation of individual elements. XFI reveals increased concentrations of P, S, K, Ca within stimulated fibroblasts. Furthermore, XAS studies reveal alterations in the speciation of S and Ca in stimulated fibroblasts, which might provide insight into the mechanisms of cancer progression. Using XFI, not only is the concentration change of individual elements observed, but also the subcellular localization. This study demonstrates the wealth of biochemical information provided by a multi-modal imaging approach and highlights new avenues for future research into the microenvironment of breast tumors

Fatal BK polyomavirus-associated pneumonia: report of two cases with literature review

Abstract Background In immunocompromised populations, such as patients with AIDS and recipients of solid organ and hematopoietic stem cell transplants, BK polyomavirus (BKPyV) can reactivate and cause several diseases, which can lead to death in their severe forms. Unlike hemorrhagic cystitis and BKPyV-associated nephropathy, BKPyV-associated pneumonia is rare, with only seven known cases worldwide. However, the disease can rapidly progress with extremely high mortality. Case presentation Herein, we report two cases of BKPyV-associated pneumonia following hematopoietic stem cell transplantation. Both patients had consistent infectious pneumonia and graft-versus-host disease after stem cell transplantation. The diagnosis of BKPyV-associated pneumonia was confirmed by metagenomic next-generation sequencing and polymerase chain reaction after the sudden worsening of the pulmonary infection signs and symptoms concomitant with renal dysfunction and systemic immune weakening. Both patients eventually died of systemic multi-organ failure caused by severe pneumonia. Conclusions Currently, BKPyV reactivation cannot be effectively prevented. Immunocompromised patients must actively manage their primary lung infections, pay close attention to pulmonary signs and imaging changes. Especially during and after steroid pulse therapy or immunosuppressive therapy for graft versus host diseases, BKPyV load in blood/urine needs to be regularly measured, and the immunosuppressive intensity should be adjusted properly after the BKPyV reactivation diagnosis. Clinical trials of new antiviral drugs and therapies for BKPyV are urgently needed