Microscale measurements of protein complexes from single cells.

Proteins execute numerous cell functions in concert with one another in protein-protein interactions (PPI). While essential in each cell, such interactions are not identical from cell to cell. Instead, PPI heterogeneity contributes to cellular phenotypic heterogeneity in health and diseases such as cancer. Understanding cellular phenotypic heterogeneity thus requires measurements of properties of PPIs such as abundance, stoichiometry, and kinetics at the single-cell level. Here, we review recent, exciting progress in single-cell PPI measurements. Novel technology in this area is enabled by microscale and microfluidic approaches that control analyte concentration in timescales needed to outpace PPI disassembly kinetics. We describe microscale innovations, needed technical capabilities, and methods poised to be adapted for single-cell analysis in the near future.

Dual-polarity MALDI mass spectrometry and imaging of oil binders and fatty acids in artworks using cyanographene as a single matrix.

Matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) and imaging mass spectrometry (IMS) are being increasingly recognized for the detection and visualization of various organic species including lipids and fatty acids. Nevertheless, most MALDI matrices perform optimally in one ionization mode. This study investigates the performance of cyano derivative of graphene (G-CN) as a matrix in two polarities of MALDI MS and IMS for the detection of oil binders and fatty acids in artworks, and compares it with classical MALDI matrices (2,5-dihydroxybenzoic acid, 9-aminoacridine). Results revealed the ability of G-CN to provide high quality positive and negative mass spectra of oils and fatty acids, respectively, with lowest matrix-induced interferences among tested matrices and minimal effects of the presence of inorganic pigments. The newly developed approach makes both oil and fatty acid identifiable in a single spot simply by covering the sample surface with one matrix and switching the polarity in MALDI without any sample manipulation. G-CN offers effective matrix to analyte energy transfer, ability to detect components in less than 100 ng of oil at a MALDI spot and lesser analyte fragmentation than the compared conventional matrices. Furthermore, it enables direct mapping of specific m/z features corresponding to triacylglycerol (TAG), products of TAG oxidation and deprotonated acids using one nanoparticle matrix in MALDI IMS. This research shows potential for technical innovations in the study of art micro-environments and degradation phenomena of historical artworks.

The impact of biochar on soil carbon sequestration: Meta-analytical approach to evaluating environmental and economic advantages.

Soil carbon (SC) is important for food security, ecosystem functioning, and environmental health, especially in light of global climate change. The physico-chemical character of biochar (pyrolyzed crop residue) has been shown to augment SC levels. This review systematically compares the environmental and economic benefits of applying crop residue versus biochar produced from crop residues to soils and the potential implications for SC sequestration. Crop residues enhance the mineralization rate of SC, while biochar can increase or decrease SC depending on the types of biochar/soil and duration. Therefore, converting crop residues to biochar may be more efficient for sequestering SC, but may/may not be more cost-effective. In this review, special emphasis is given to understanding the underlying mechanisms and biogeochemical processes of biochar production, in particular: surface (crystallinity), redox, and ability to control electron transfer reactions. By using meta-analytics, we determined the role of biochar compared to crop residue to enhance the status of organic SC.

Nano MOF Entrapping Hydrophobic Photosensitizer for Dual-Stimuli-Responsive Unprecedented Therapeutic Action against Drug-Resistant Bacteria.

Multidrug resistance (MDR) of bacteria is a major threat to public health globally and its unprecedented increase calls for immediate alternative medical strategies. Antimicrobial photodynamic therapy (aPDT) offers alternative modalities to combat the growing MDR typically by means of targeted cellular internalization of a photosensitizer (PS) capable of producing photoinduced reactive oxygen species (ROS). However, aPDT is severely limited by the self-aggregation behavior and hydrophobicity of PS molecules, which significantly curbs its viability for clinical application. The present study reports the use of modified nanoscale metal-organic frameworks (NMOFs) encapsulating a hydrophobic PS drug squaraine (SQ) to enhance aPDT efficacy against drug-resistant planktonic bacteria and its biofilm for the first time. Zeolitic imidazolate framework (ZIF-8) NMOF nanocrystals are attached postsynthetically with SQ (designated as ZIF8-SQ) and the resultant drug-doped NMOF is characterized by TEM, FESEM, PXRD, Raman spectroscopy, UV-vis spectroscopy, and steady-state and time-resolved fluorescence techniques. The microporous structures of ZIF-8 behave as molecular cages ceasing the self-aggregation of hydrophobic SQ. In addition, the formulated ZIF8-SQ produces cytotoxic ROS under red-light irradiation (650 nm) in a pH sensitive way primarily due to molecular level interaction and charge separation between ZIF-8 and SQ depicting a dual-stimuli-responsive nature. Most notably, ZIF8-SQ provides unparalleled aPDT action against methicillin-resistant Staphylococcus aureus (MRSA) and leads to complete loss of adherence of structurally robust bacterial biofilms. Finally, the nontoxic nature of the nanoconjugate toward human cells holds great promise for effective treatment of MRSA and other detrimental antibiotic-resistant microbes in clinical models.

'Green' synthesis of metals and their oxide nanoparticles: applications for environmental remediation.

In materials science, "green" synthesis has gained extensive attention as a reliable, sustainable, and eco-friendly protocol for synthesizing a wide range of materials/nanomaterials including metal/metal oxides nanomaterials, hybrid materials, and bioinspired materials. As such, green synthesis is regarded as an important tool to reduce the destructive effects associated with the traditional methods of synthesis for nanoparticles commonly utilized in laboratory and industry. In this review, we summarized the fundamental processes and mechanisms of "green" synthesis approaches, especially for metal and metal oxide [e.g., gold (Au), silver (Ag), copper oxide (CuO), and zinc oxide (ZnO)] nanoparticles using natural extracts. Importantly, we explored the role of biological components, essential phytochemicals (e.g., flavonoids, alkaloids, terpenoids, amides, and aldehydes) as reducing agents and solvent systems. The stability/toxicity of nanoparticles and the associated surface engineering techniques for achieving biocompatibility are also discussed. Finally, we covered applications of such synthesized products to environmental remediation in terms of antimicrobial activity, catalytic activity, removal of pollutants dyes, and heavy metal ion sensing.

Phytochemical-assisted synthetic approaches for silver nanoparticles antimicrobial applications: A review.

Silver nanoparticles (Ag NPs) have recently emerged as promising materials in the biomedical sciences because of their antimicrobial activities towards a wide variety of microorganisms. Nanomaterial-based drug delivery systems with antimicrobial activity are critical as they may lead to novel treatments for cutaneous pathogens. In this review, we explore the recent progress on phytochemical-mediated synthesis of Ag NPs for antimicrobial treatment and associated infectious diseases. We discuss the biological activity of Ag NPs including mechanisms, antimicrobial activity, and antifungal/antiviral effects towards various microorganisms. The advent of Ag NP-based nanocarriers and nano-vehicles is also described for treatment of different diseases, along with the mechanisms of microbial inhibition. Overall, this review will provide a rational vision of the main achievements of Ag NPs as nanocarriers for inhibition of various microbial agents (bacteria, fungus, and virus).

Metal-organic framework and Tenax-TA as optimal sorbent mixture for concurrent GC-MS analysis of C1 to C5 carbonyl compounds.

We report a multi adsorbent-based method using combinations of metal-organic frameworks (MOFs) and a commercial sorbent Tenax-TA for sampling and thermal desorption (TD) gas chromatography-mass spectrometry (GC-MS) quantification of mixtures of six (C1 to C5) aldehydes. The feasibility of this approach was demonstrated along with the optical analytical conditions for maximum recovery. Optimal TD conditions for adsorption and desorption of aldehydes using MOF-5 (Zn-based MOF)+ Tenax-TA were determined as -25 °C and 150 °C, respectively (purge volume: 100 ml). These conditions yielded good linearity (R2 = 0.997), precision, and high sensitivity. Analysis of the aldehyde mixtures yielded slightly smaller R2 values than the analysis of single species. Additionally, the performance of MOF-5+ Tenax-TA was compared with other combinations comprising of Cu-based MOF-199 and Zr-based MOF of UiO-66 topology. The results of the theoretical modelling analyses propose simultaneous interaction of the C=O group of aldehydes with open metal sites of the studied MOFs and van der Waals interaction of hydrocarbon "tail" of aldehydes with linkers of MOFs. The combined interactions significantly increased the enthalpy (eV/molecule) of formaldehyde adsorption on MOF. Our findings unravel a potential way to extend the application of GC-based detection toward concurrent analysis of organic molecules of variable sizes.

The micro-environmental impact of volatile organic compound emissions from large-scale assemblies of people in a confined space.

Large-scale assemblies of people in a confined space can exert significant impacts on the local air chemistry due to human emissions of volatile organics. Variations of air-quality in such small scale can be studied by quantifying fingerprint volatile organic compounds (VOCs) such as acetone, toluene, and isoprene produced during concerts, movie screenings, and sport events (like the Olympics and the World Cup). This review summarizes the extent of VOC accumulation resulting from a large population in a confined area or in a small open area during sporting and other recreational activities. Apart from VOCs emitted directly from human bodies (e.g., perspiration and exhaled breath), those released indirectly from other related sources (e.g., smoking, waste disposal, discharge of food-waste, and use of personal-care products) are also discussed. Although direct and indirect emissions of VOCs from human may constitute <1% of the global atmospheric VOCs budget, unique spatiotemporal variations in VOCs species within a confined space can have unforeseen impacts on the local atmosphere to lead to acute human exposure to harmful pollutants.

2D visualization captures the local heterogeneity of oxidative metabolism across soils from diverse land-use.

Fine-scale processes in soils affect large-scale phenomena by controlling mixing and reaction rates, yet technological constraints have hampered the collection of micro-scale kinetic data. As a result, limited information is available on the magnitude of fine-scale biogeochemical rates and their temporal and spatial pattern in response to environmental perturbations. In this work we investigate the spatio-temporal dynamics in oxidative microbial activity and the development of anoxic micro zones (i.e., anoxic hot-spots) at the microscopic level (µm - cm). These analyses rely on novel non-invasive & non-destructive optodes, which are able to capture real-time imaging of oxygen concentrations over time at an interval of twenty seconds. Results showed that labile carbon addition resulted in maximum rates of local metabolic activity within a few minutes (5 to 15) and led to the subsequent formation of anoxic hot-spots. Different areas within a given soil sample presented up to one order of magnitude variation in metabolic rate values. As a result, oxic and anoxic micro-zones coexisted closely. The relationship between oxygen concentrations and heterogeneity of oxidative metabolism resulted in an initial increase in metabolic heterogeneity over time followed by a decrease when anoxic conditions dominated. A similar link was found by comparing metabolic activity and its heterogeneity across a range of soil types. These results demonstrate that the microbial activity and hot-spot development can be monitored by using a non-invasive quantitative imaging system that allows real-time monitoring of spatial oxygen distribution. We conclude that local dynamics of heterogeneity in space and time at the fine-scale present the same functional behavior encountered in most ecosystems at the landscape-scale.

Monitoring of airborne particulate matter at mountainous urban sites.

Concentrations of various size fractions (TSP, PM10, PM2.5, and PM1.0) of particulate matter (PM) were measured at two mountainous sites, Buk Han (BH) and Gwan AK (GA), along with one ground reference site at Gwang Jin (GJ), located in Seoul, South Korea for the 4 years from 2010 to 2013. The daily average concentrations of TSP, PM10, PM2.5, and PM1.0 at BH were 47.9 ± 32.5, 37.0 ± 24.6, 20.6 ± 12.9, and 15.3 ± 9.53 µg m(-3), respectively. These values were slightly larger than those measured at GA while much lower than those measured at the reference site (GJ). Seasonal variations in PM concentrations were consistent across all locations with a relative increase in concentrations observed in spring and winter. Correlation analysis showed clear differences in PM concentrations between the mountainous sites and the reference site. Analysis of these PM concentrations indicated that the distribution of PM in the mountainous locations was affected by a number of manmade sources from nearby locations, including both traffic and industrial emissions.

Global demand for rare earth resources and strategies for green mining.

Rare earth elements (REEs) are essential raw materials for emerging renewable energy resources and 'smart' electronic devices. Global REE demand is slated to grow at an annual rate of 5% by 2020. This high growth rate will require a steady supply base of REEs in the long run. At present, China is responsible for 85% of global rare earth oxide (REO) production. To overcome this monopolistic supply situation, new strategies and investments are necessary to satisfy domestic supply demands. Concurrently, environmental, economic, and social problems arising from REE mining must be addressed. There is an urgent need to develop efficient REE recycling techniques from end-of-life products, technologies to minimize the amount of REEs required per unit device, and methods to recover them from fly ash or fossil fuel-burning wastes.

Characteristics attributed to complementary foods by caregivers in four countries of Latin America and the Caribbean.

BACKGROUND: Attributes that caregivers assign to complementary foods have been primarily described in the context of illness, but attributes assigned to foods in everyday circumstances must be understood to effectively promote good complementary feeding. OBJECTIVE: This study aimed to understand how mothers judge complementary foods to be appropriate by cross-cultural examination of food perceptions in four different Latin American and Caribbean countries. METHODS: We used semistructured interviews to assess attributes that mothers ascribed to a list of key foods, both home-made and manufactured, and reasons for feeding or not feeding them. We elicited attributes from 79 caregivers with children 6 to 24 months of age from two urban and perirban sites each in Brazil, Jamaica, Mexico, and Panama. RESULTS: Textual analysis based on six home foods common to the four countries and manufactured foods resulted in six attribute categories, five of which could be positive or negative (Nutrient Content, Effects on Child, Child's Response, Availability and Accessibility, and Other Food Attributes); one (Food Quality and Safety) was only negative. Analysis of attributes of home foods (chicken, eggs, beans, carrots, bananas or plantains, and oranges) revealed many beliefs that were common within and across countries, whereas analysis of the attributes of manufactured foods revealed that these foods were less known. CONCLUSIONS: The consistency of the attribute categories across countries and across home and manufactured foods suggests their relevance to planning programs to improve complementary feeding in Latin America and the Caribbean and possibly other developing countries. These results can be used programmatically to assess the need for and the focus of food education programs, and to indicate which countries will be more receptive to certain foods as a means of improving complementary feeding.