Commonly consumed processed packaged foods in Bangladesh are unhealthy and their nutrient contents are not in conformity with the label declaration.

The present study was undertaken to identify the major nutrient content in processed foods commonly consumed in Bangladesh, their label conformity healthiness, and percent daily nutrient contribution. Twenty-four nationally representative composite samples were analyzed using AOAC and other standard methods. Results were compared with label information using a restrictive approach and EU tolerance guidelines. The healthiness of the products was evaluated in terms of the Health Star Rating (HSR) scheme and the UK traffic light labeling system. Among the analyzed samples, fried pulse, chanachur, lozenge, and fried peas had the highest amount of protein, fat, carbohydrates, and dietary fiber, respectively. Biscuits and milk chocolate had high levels of trans fatty acids (TFA) and saturated fatty acids (SFA). It was observed that around half of the products lacked information about saturated fatty acid (46%), followed by total dietary fiber and trans-fat (38% each). Other information was missing in one-fifth of the products, namely protein (17%), total fat (17%), available carbohydrate (17%), energy (17%), sugar (21%), and salt (21%). Label compliance analysis according to the restrictive approach revealed that none of the products accurately reported the salt, sugar, saturated fat, and trans fat content on the label. According to the EU tolerance guideline, approximately half of the products had protein (58%), fat (54%), and carbohydrate (42%) levels that fell within the EU tolerance limit. However, only around one-third of the samples had sugar (21%), salt (38%), and saturated fat (33%) levels that met the EU tolerance limit. In terms of healthiness analysis, according to the HSR, the range of stars was between 0.5 and 2.5 of the foods where fried peas got the highest rating (2.5 stars), while in terms of the UK traffic light system, none of the samples got all green signals. The lozenge got green lights for fat, SFA, and salt contents. It was also found that consumption of 100 g of fried peas or pulse would exceed the acceptable daily limit of salt, sugar, and SFA compared to the daily maximum allowable intake for the 2000 kcal diet recommended by the WHO. However, according to the serving size, biscuits were major contributors of TFA, sugar, and SFA, whereas fried pulse was a key contributor of sodium/salt. Proper regulatory actions should be introduced to promote healthy processed foods with user-friendly front-of-the-pack labeling and monitor their quality to prevent non-communicable diseases (NCDs).

Customized Production of Holey Graphene Oxides via a Continuous Flow Process.

Continuous flow manufacturing is an innovative technology mainly applied in the chemical and pharmaceutical industries that is progressively being adapted to the manufacturing of nanomaterials to overcome the challenge of reproducing a product with consistent characteristics at a large scale. Here, a flow photochemical system is designed and prototyped for the synthesis of holey graphene oxides (hGOs). Compared to existing methods for the synthesis of hGO, the process is fast, highly scalable, and controllable. Through a combination of rigorous data analysis using machine learning algorithms on transmission electron microscope images and systematic studies of process parameters, it is demonstrated that characteristics of the produced hGO (i.e., porosity and pore size) are remarkably reproducible to the extent that it can be predicted by empirical models of processing-property correlations. Depending on the tailored nanopore structures, the synthesized hGOs out-performed GO in a range of applications that can benefit from the nanoporous two-dimensional (2D) sheets such as in supercapacitors, gas adsorption, and nanofiltration membranes. These results are significant in offering new perspectives on the low-cost industrialization of 2D nanomaterials.

New Class of High-Energy, High-Power Capacitive Devices Enabled by Stabilized Lithium Metal Anodes.

Lithium-ion capacitors (LIC) combine the energy storage mechanisms of lithium-ion batteries and electric double layer capacitors (EDLC) and are supposed to promise the best of both worlds: high energy and power density combined with a long life. However, the lack of lithium cation sources in the carbon cathode demands the cumbersome step of prelithiation of the graphite anode, mainly by using sacrificial lithium metal, hindering the mass adoption of LICs. Here, in a conceptually new class of devices termed lithium metal capacitors (LMC), we replace the graphite anode with a lithium metal anode stabilized by a complex yet stable solid-electrolyte interface (SEI). Via a specialized formation process, the well-explored synergetic reaction between the LiNO3 additive and controlled amounts of polysulfides in an ether-based electrolyte stabilizes the SEI on the lithium metal electrode. Optimized devices at the coin cell level deliver 55 mAh g-1 at a fast 30C discharge rate and maintain 95% capacity after 8000 cycles. At the pouch-cell level, energy densities of 13 Wh kg-1 are readily achieved, indicating the transferability of the technology to practical scales. The LMC, a new class of capacitive device, eliminates the prelithiation process of the conventional LIC, allowing practical production at scale and offering exciting avenues for exploring versatile cathode chemistries on account of using a lithium metal anode.

Low-cost informational intervention reduced drinking water arsenic exposure in Bangladesh.

Thirty million Bangladeshis continue to drink water with unacceptable levels of arsenic (>10 µg/L), resulting in a large public health burden. The vast majority of the Bangladeshi population relies on private wells, and less than 12% use piped water, increasing the complexity of mitigation efforts. While mass testing and informational campaigns were successful in the early 2,000 s, they have received little attention in recent years, even though the number of wells in the country has likely more than doubled. We investigated the effect of a low-cost (

A High Throughput and Unbiased Machine Learning Approach for Classification of Graphene Dispersions.

Significant research to define and standardize terminologies for describing stacks of atomic layers in bulk graphene materials has been undertaken. Most methods to measure the stacking characteristics are time consuming and are not suited for obtaining information by directly imaging dispersions. Conventional optical microscopy has difficulty in identifying the size and thickness of a few layers of graphene stacks due to their low photon absorption capacity. Utilizing a contrast based on anisotropic refractive index in 2D materials, it is shown that localized thickness-specific information can be captured in birefringence images of graphene dispersions. Coupling pixel-by-pixel information from brightfield and birefringence images and using unsupervised statistical learning algorithms, three unique data clusters representing flakes (unexfoliated), nanoplatelets (partially exfoliated), and 2D sheets (well-exfoliated) species in various laboratory-based and commercial dispersions of graphene and graphene oxide are identified. The high-throughput, multitasking capability of the approach to classify stacking at sub-nanometer to micrometer scale and measure the size, thickness, and concentration of exfoliated-species in generic dispersions of graphene/graphene oxide are demonstrated. The method, at its current stage, requires less than half an hour to quantitatively assess one sample of graphene/graphene oxide dispersion.

Evaluation of arsenic field test kits for drinking water: Recommendations for improvement and implications for arsenic affected regions such as Bangladesh.

Arsenic field test kits are widely used to measure arsenic levels in drinking water sources, especially in countries like Bangladesh, where water supply is highly decentralized and water quality testing infrastructure is limited. From a public health perspective, the ability of a measurement technique to distinguish samples above and below relevant and actionable drinking water standards is paramount. In this study, the performance of eight commercially available field test kits was assessed by comparing kit estimates to hydride generation atomic absorption spectroscopy (HG-AAS) analyses. The results of tests that control for user-dependent color matching errors showed that two kits (LaMotte and Quick II kits) provided accurate and precise estimates of arsenic, four kits (Econo-Quick, Quick, Wagtech and Merck kits) were either accurate or precise, but not both, and two kits (Hach and Econo-Quick II kits) were neither accurate nor precise. Tests were performed for arsenic concentration ranges commonly found in natural waters and treated waters (such as community drinking water filter systems), and also on laboratory generated arsenic standards in DI water. For those kits that did not perform well, test strips often produced colors too light compared to manufacturer-provided arsenic color calibration charts. Based on these results, we recommend stakeholders carefully re-consider the use of poorly performing field test kits until better quality control of components of these kits is implemented. In addition, we recommend that field test kit manufacturers provide suitable internal standards in every kit box for users to verify the veracity of manufacturer provided color charts.

Graphene Oxide Liquid Crystal Domains: Quantification and Role in Tailoring Viscoelastic Behavior.

Graphene oxide liquid crystals (GOLCs) were exfoliated in a wide variety of solvents (water, ethylene glycol (EG), N-methyl-2-pyrrolidone (NMP), and dimethylformamide (DMF)) by high-speed shearing of graphite oxide. Quantitative polarized light imaging of the equilibrium nematic phases of the lyotropic GOLCs gives insights into the extent of aggregation and quantifiable textural features such as domain size, d. Large nematic domains >100 µm with a high overall degree of order were obtained in water and ethylene glycol, in contrast to ∼5-50 µm domains in NMP and DMF at comparable volume fractions. Comprehensive rheological studies of these GOLCs indicate that larger domains correlate with higher viscosity and higher elasticity, and scaling analysis shows a power-law dependence of the Ericksen number (Er) with domain size (Er ∝ d3.09). The improved understanding of the relationship between the microstructure and flow properties of GOLCs leads us to an approach of mixed solvent-based GOLCs as a means to tune viscoelastic properties. We demonstrate this approach for the formation of shear-aligned GOLC films for advanced flexible electronic applications such as all-carbon conductive films and thermal heaters.

Graphene oxide-silica hybrid capsules for sustained fragrance release.

Encapsulation of active or valuable cargoes has become one of the most important methods for controlled delivery and release. However, many existing capsule technologies suffer from scalability issues, and capsules from surfactant- or polymer-stabilised emulsions tend to have weak shells or limited stability. Here we present a robust and scalable method for the surfactant-free preparation of silica hybrid capsules templated from Pickering emulsions stabilised by graphene oxide. These capsules are produced using a single step, undemanding formulation process with cheap and scalable precursors. The mechanical and chemical stability provided by the silica shell grown around these droplets is explored using surface pressure measurements and atomic force microscopy, demonstrating that a rigid and robust capsule is produced from higher loadings of silica precursor. In order to demonstrate the utility of these capsules, the sustained release of a fragrance molecule (vanillin) from the capsules is monitored, and compared to release from unencapsulated vanilla oil. It is seen that the capsules retain the fragrance for multiple weeks, offering new pathways for scalable encapsulation systems for the delivery of valuable actives.