Aim and shoot: molecule-imprinting polymer coated MoO3 for selective SERS detection and photocatalytic destruction of low-level organic contaminants

A sensitive and selective SERS sensor with easy and excellent recyclability is highly demanded because of its great potential application in complex detection environments. Here, using methylene blue (MB) as a model target, a semiconductor-based SERS substrate composed of a MoO3 nanorod core and a uniform molecule-imprinting polymethacrylic acid shell (MIP) with a thickness of 4 nm was designed and fabricated (MoO3@MIP) to achieve selective detection. The key to the successful coating of the ultrathin uniform MIP shell lies in the pretreatment of a MoO3 core with nitric acid, providing sufficient surficial hydroxyls for the anchoring of a polymer precursor. The molecule-imprinted voids for MB were formed simply via light irradiation as a result of photocatalytic degradation by a MoO3 semiconductor. This core–shell MIP composite shows a high SERS selectivity towards low-level MB in a mixed MB/CV solution. The enhanced factor (EF) is high, at 1.6 × 104. More importantly, the selective detection allows the further photocatalytic recycling of MoO3@MIP in an “aim-and-shoot” way, which well preserves the detection selectivity and sensitivity towards MB at least for 4 cycles. Based on decreased sensitivity with the increasing shell thickness (10–24 nm), a MIP-gating charge transfer mechanism is proposed to demonstrate the high EF instead of the molecule-enrichment effect. This “aim-and-shoot” strategy is expected to push forward the prosperous application of selective SERS for trace detection in versatile environments

Data for Housing Justice: Examining Activists’ Use of Open Government Data for Housing Justice in Boston, MA and New York, NY

Over the past decade, governments the world over have expanded access to public data through open government data (OGD) portals, from the local to national levels. The Organization for Economic Cooperation and Development describes OGD as a philosophy and a set of politics that aims to serve three social, political, and economic ends: transparency, accountability and value creation. Despite governmental efforts to make data public, research shows that OGD is underutilized and that little is known about citizens’ preferences and interests in utilizing these data. In the U.S., a recent study of a grassroots organization focused on affordable housing described a case of resident-initiated data collection to counteract misrepresentations and misalignments of the local municipal data. Given this disjuncture between the data needs of grassroots actors and the data provided by OGD systems, my study focuses on understanding how local activists negotiate limitations of public data and develop strategies to collect the information they need in their broader campaigns for housing justice. Applying theories of data feminism and insurgent planning, I analyze data practices of housing data activists in Boston and New York City. Through their activities, housing data activists act as data intermediaries who bridge the gap between OGD systems and residents and community organizers. In doing so, they not only facilitate local government’s fulfillment of its goals of transparency and accountability, but also pursue a more liberatory and justice-oriented future for communities facing the threat of displacement. Housing ‘data activists’ utilize a data justice approach that relates historical and contextual analysis of structural oppression to the contemporary geography of the eviction crisis, and proactively counters parallel data practices within the real estate industry to facilitate tenant management and real estate speculation. I argue that OGD systems represent a new opportunity for government officials to take action in order to redress the long-standing power differentials between local tenants and organizers and the real estate industry. If government officials take seriously the values of transparency and accountability, they must take cues from the housing data activists in redesigning OGD systems in such a way that privileges and facilitates use by local residents over use by real estate firms.M.C.P

Water treatment: functional nanomaterials and applications from adsorption to photodegradation

Global efforts for engineering desired materials which are able to treat the water sources still are ongoing in the bench level methods. Considering adsorbent and photocatalytic materials as the main reliable candidates still are encountering with struggles because of many challenges that restrict their large-scale application. This review comprehensively considered the recent advanced materials water treatment methods which involve to magnetic, activated carbon, carbon nanotubes (CNTs), graphene (G), graphene oxide (GO), (Graphene) quantum dots, carbon nanorods, carbon nano-onions, and reduced graphene oxide (RGO), zeolite, silica and clay-based nanomaterials. The adsorption and photocatalytic properties of these nanomaterials introduced them as highly potent option for heavy metal ions and organic dyes removal and photocatalytic degradation. High specific surface area in conjugation with presenting higher kinetics of adsorption and decomposition are the main characteristics of these materials which make them appropriate to treat wastewater even in ultralow concentration of the pollutants. Considering the mechanistic aspects of the adsorption and photocatalytic decomposition process, challenges and opportunities were other subjects that have been highlighted for the discussed nanomaterials. In term of the adsorption approaches, the mechanism of adsorptions and their influence on the maximum adsorption capacity were discussed and also for photocatalyst approach the radical active spices and their role in kinetic and efficiency of the organic pollutant decomposition were provided a deep discussion. © 2020 Elsevier Lt

Designing High-Quality Electrocatalysts Based on CoO:MnO₂@C Supported on Carbon Cloth Fibers as Bifunctional Air Cathodes for Application in Rechargeable Zn–Air Battery

To achieve the requirements of rechargeable Zn–air batteries (ZABs), designing efficient, bifunctional, stable, and cost-effective electrocatalysts is vital for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which still are struggling with unsolved challenges. The present research provides a concept based on the nanoscale composites which were engineered by using MnO2@C, CoO@C, and CoO:MnO2@C bifunctional electrocatalysts for fabrication of uniform carbon cloth (CC)-based electrodes. The CoO:MnO2@C electrocatalyst represented more efficient electrochemical properties through ORR and OER processes with superior positive half-wave potential (E1/2 = 0.78 V) and better limiting current density (i = 1.10 mA cm–2) in comparison with MnO2@C (E1/2 = 0.71 V, i = 0.92 mA cm–2) and CoO@C (E1/2 = 0.69 V, i = 0.86 mA cm–2) electrocatalysts. For the rechargeable ZABs fabricated by using CoO:MnO2@C–CC as an O2-breathing cathode, the specific capacity (SC), peak power density (P), open-circuit voltage (EOCV), and gap of charge/discharge voltage resulted in values of 520 mAh gZn–1, 210.0 mW cm–2, and 1.45 and 0.45 V, respectively, that afforded greater electrochemical characters than what was obtained for ZABs based on MnO2@C–CC (410 mAh gZn–1, 195.0 mW cm–2, 1.38 and 0.44 V) and CoO@C–CC (440 mAh gZn–1, 165.0 mW cm–2, 1.15 and 0.54 V). At the same time, lower Ei=10 (= 1.45 V) implied a more efficient OER in alkaline electrolyte solution for CoO:MnO2@C than MnO2@C (Ei=10 = 1.50 V) and CoO@C (Ei=10 = 1.39 V). Based on cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and X-ray photoelectron spectroscopy (XPS) results, it could be stated that the CoO:MnO2@C catalytic surface could experience 30 and 32% lower charge transfer resistance (Rct = 13.9 Ω) than MnO2@C (Rct = 20.1 Ω) and CoO@C (Rct = 29.7 Ω), respectively, which empowers an enhancement in ORR/OER performance. Prominently, the design concept of proposed electrocatalysts could suggest clear horizon for the synthesis and development paradigms of bifunctional catalysts for energy storage materials and devices

Biological Applications of Bacterial Nano-Surface Layers : A Brief Overview

Surface layer as the outer protective coverage of bacteria and archaea are two-dimensional crystalline and symmetrical arrays of proteins that recently attract a lot of attention for biologist scientists. The surface layers of bacteria are usually 5 to 10 nm in diameter and represent highly porous protein lattices with uniform size and morphology with the pore sizes of 2 to 8 nm. The crucial and most prominent property of this protein-based layer is the regular morphology and suitable chemical composition for different biological applications. Although the formation mechanism of surface layers is different from one type of cell to another once, the surface layer protein molecular compositions almost are same for all types. Recently, the biological application of surface layers opens a prominent research fields in surface biological science such as nano-biotechnology adhesion, vaccination, pharmaceutical, biosensors, bioremediation and mineralization application. In this mini review, we discussed about the main application of this nano-layer in biological systems

Biomedical applications of nanoflares: Targeted intracellular fluorescence probes

Nanoflares are intracellular probes consisting of oligonucleotides immobilized on various nanoparticles that can recognize intracellular nucleic acids or other analytes, thus releasing a fluorescent reporter dye. Single-stranded DNA (ssDNA) complementary to mRNA for a target gene is constructed containing a 3�-thiol for binding to gold nanoparticles. The ssDNA �recognition sequence� is prehybridized to a shorter DNA complement containing a fluorescent dye that is quenched. The functionalized gold nanoparticles are easily taken up into cells. When the ssDNA recognizes its complementary target, the fluorescent dye is released inside the cells. Different intracellular targets can be detected by nanoflares, such as mRNAs coding for genes over-expressed in cancer (epithelial-mesenchymal transition, oncogenes, thymidine kinase, telomerase, etc.), intracellular levels of ATP, pH values and inorganic ions can also be measured. Advantages include high transfection efficiency, enzymatic stability, good optical properties, biocompatibility, high selectivity and specificity. Multiplexed assays and FRET-based systems have been designed. © 201

Dengue virus: a review on advances in detection and trends � from conventional methods to novel biosensors

Dengue virus is an important arbovirus infection which transmitted by the Aedes female mosquitoes. The attempt to control and early detection of this infection is a global public health issue at present. Because of the clinical importance of its detection, the main focus of this review is on all of the methods that can offer the new diagnosis strategies. The advantages and disadvantages of reported methods have been discussed comprehensively from different aspects like biomarkers type, sensitivity, accuracy, rate of detection, possibility of commercialization, availability, limit of detection, linear range, simplicity, mechanism of detection, and ability of usage for clinical applications. The optical, electrochemical, microfluidic, enzyme linked immunosorbent assay (ELISA), and smartphone-based biosensors are the main approaches which developed for detection of different biomarkers and serotypes of Dengue virus. Future efforts in miniaturization of these methods open the horizons for development of commercial biosensors for early-diagnosis of Dengue virus infection. Figure not available: see fulltext.. © 2019, Springer-Verlag GmbH Austria, part of Springer Nature

Carbon based nanomaterials for tissue engineering of bone: Building new bone on small black scaffolds: A review

Tissue engineering is a rapidly-growing approach to replace and repair damaged and defective tissues in the human body. Every year, a large number of people require bone replacements for skeletal defects caused by accident or disease that cannot heal on their own. In the last decades, tissue engineering of bone has attracted much attention from biomedical scientists in academic and commercial laboratories. A vast range of biocompatible advanced materials has been used to form scaffolds upon which new bone can form. Carbon nanomaterial-based scaffolds are a key example, with the advantages of being biologically compatible, mechanically stable, and commercially available. They show remarkable ability to affect bone tissue regeneration, efficient cell proliferation and osteogenic differentiation. Basically, scaffolds are templates for growth, proliferation, regeneration, adhesion, and differentiation processes of bone stem cells that play a truly critical role in bone tissue engineering. The appropriate scaffold should supply a microenvironment for bone cells that is most similar to natural bone in the human body. A variety of carbon nanomaterials, such as graphene oxide (GO), carbon nanotubes (CNTs), fullerenes, carbon dots (CDs), nanodiamonds and their derivatives that are able to act as scaffolds for bone tissue engineering, are covered in this review. Broadly, the ability of the family of carbon nanomaterial-based scaffolds and their critical role in bone tissue engineering research are discussed. The significant stimulating effects on cell growth, low cytotoxicity, efficient nutrient delivery in the scaffold microenvironment, suitable functionalized chemical structures to facilitate cell-cell communication, and improvement in cell spreading are the main advantages of carbon nanomaterial-based scaffolds for bone tissue engineering. © 201