Mg Of Material Research Articles

Smartphone-enabled composite of cellulose nanocrystals for rapid and selective mercury detection in cosmetics and water: insights from density functional theory studies

ABSTRACT The pervasive contamination of cosmetics and water with mercury ions (Hg(II)) poses severe health risks, driving the need for efficient methods for in situ detection and removal of it. Our study showcases a groundbreaking composite material that combines cellulose nanocrystals (CNCs) and smartphones for the purpose of rapid and selective mercury detection. The CNCs exhibit a distinctive rod-like morphology, presenting a high surface area that facilitates the accommodation of the Hg(II) ion probe, 4-(dimethylamino)phenyl)methanethione (DPM). This interaction leads to a distinct colour change from yellow to green, visible to the naked eye, enabling straightforward visual detection. Our composite is highly sensitive, with a limit of detection (LOD) of 1.76 × 10 − 8 M using digital image analysis and 3.6 × 10 − 8 M using spectrophotometric methods. These values are significantly below the safe drinking water guidelines set by the World Health Organization (WHO). Density functional theory (DFT) calculations were used to understand how Hg(II) ions interact with the DPM-CNC composite. These calculations confirmed that the material has a strong affinity for Hg(II) ions and demonstrated its selective detection capabilities. The DPM-CNC composite’s low detection threshold, rapid response time, and ease of regeneration make it a potent candidate for practical applications in mercury monitoring. This composite is a robust and reusable solution for real-time visualisation and quantification of mercury ions. It only requires 10 mg of material for effective measurements. It enhances safety in cosmetic products and water.

In-situ hydrogen-generating injectable short fibers for osteoarthritis treatment by alleviating oxidative stress

Hydrogen (H₂) has great potential in the treatment of osteoarthritis, but its rapid diffusion and short retention time make it difficult to exert stable therapeutic effects. This study developed a short-fiber injectable material that can continuously generate hydrogen in situ to eliminate reactive oxygen species (ROS), alleviate oxidative stress and inflammation, and promote tissue repair. We prepared H–Si nanosheets with high hydrogen generation efficiency using a wet chemical exfoliation method and combined them with GelMA short fibers via electrospinning technology, achieving the in situ delivery of H–Si nanosheets and regulated hydrogen generation rate through the encapsulation and degradation of GelMA, ultimately achieving continuous and controlled hydrogen supply and stable therapeutic effects for osteoarthritis. In vitro and in vivo experiments confirmed the safety and efficacy of this material. The results showed that the material could continuously and efficiently generate hydrogen in simulated physiological environments (100 mg of material could generate 8.6 % hydrogen), effectively eliminate cellular reactive oxygen species (ROS positive rate reduced by 85.89 %), reduce cellular senescence and apoptosis (cell death rate decreased by 52 %, SA-βgal expression decreased by 78.3 %), promote normal chondrocyte function (Col II expression increased by 67.4 %, Ki67 expression increased by 87.5 %), and improve osteoarthritis in rats (OARSI score increased by 216 %). The in situ hydrogen generation and control system designed in this study provides a new method for the hydrogen's local and stable treatment of osteoarthritis. Statement of significanceHydrogen (H₂) has great potential in the treatment of osteoarthritis by alleviating oxidative stress, but its rapid diffusion and short retention time make it difficult to exert stable therapeutic effects. This study introduces an innovative injectable material combining H–Si nanosheets and GelMA short fibers to address this issue. By enabling continuous in situ hydrogen generation, this material effectively eliminates reactive oxygen species, reduces oxidative stress and inflammation, and promotes tissue repair. In vitro and in vivo experiments demonstrate its high hydrogen generation efficiency, safety, and therapeutic efficacy, offering a promising new approach for osteoarthritis management.

Premise setting for sustainable developing adsorption in environmental remediation using graphitic carbon nitride@agar-derived porous carbon composite

In the adsorption process for wastewater treatment, the adsorbent plays an important role. A composite adsorptive material composed of graphitic carbon nitride and agar-derived porous carbon (CNPC) was fabricated from simple precursors (melamine, thiourea, and agar) and through a facile procedure with different melamine and thiourea ratios. Characterization of CNPC proved a successful formation of a porous structure consisting of mesopores and macropores, wherein CNPC holds distinctive electrochemical (lowered resistance and higher specific capacity) and photochemical properties (lowered bandgap to 2.33 eV) thanks to the combination of graphitic carbon nitride (CN) and agar-derived porous carbon (PC). Inheriting the immanent nature, CNPC was subjected to the adsorption of methylene blue (MB) dye in an aqueous solution. The highest adsorption capacity was 133 mg/g for CNPC-4 which was prepared using a melamine to thiourea ratio of 4:4 – equivalent to the removal rate of 53.2 % and following the pseudo-I-order reaction rate. The effect of pH points out that pH 7 and 9 were susceptible to maximum removal and pretreatment is not required while the optimal ratio of 7.5 mg of MB and 30 mg of material was also determined to yield the highest performance. Furthermore, the reusability of the material for three consecutive cycles was evaluated based on two methods pyrolysis at 200 °C and photocatalytic degradation by irradiation under visible light. In general, the photocatalytic regeneration pathway is more ample and efficient than pyrolysis in terms of energy efficiency (saving energy over 10 times) and adsorption capacity stability. As a whole, the construction of accessible regenerative and stable adsorbent could be a venturing step into the sustainable development spearhead for industries.

Challenges of Pt-Ni Aerogel PEMFC-Cathode Catalyst Layers Under Automotive-Relevant Conditions

Proton exchange membrane fuel cells (PEMFCs) constitute an emerging technology for the decarbonization of the transportation sector. However, in order for the price of fuel cell electric vehicles (FCEVs) to be comparable to that of internal combustion engine cars, the manufacturing costs of PEMFCs, must be significantly reduced. These costs are mainly related to the Pt-based catalysts used in PEMFCs’ anode and cathode electrodes and, as a result, extended FCEV-commercialization passes by decreasing these Pt loading to a value of 0.06-0.11 mgPt cm-2. Moreover, the automotive PEMFCs suffer from an insufficient durability that is partially due to the corrosion of the carbon support used in state-of-the-art Pt-catalysts, which is in turn induced by the high cathode potentials (> 1.5 V vs. the reversible hydrogen electrode) reached upon PEMFC start-up and/or shutdown.To tackle both these needs, in our previous work we introduced a novel catalyst layer (CL) based on a carbon-free bimetallic Pt-Ni alloy nanochain network (referred to as “aerogel”) which featured an excellent performance and start-up/shutdown durability upon PEMFC operation [1]. In a more recent work, the synthesis of this Pt-Ni aerogel was up-scaled (as to yield ≈ 120 mg of material per batch) and catalyst-coated membrane (CCM) processing methods were adapted and optimized using an automated spray-coating machine that yielded homogenous and high-performing aerogel CLs with a Pt-loading of ≈ 0.3 mgPt cm-2.The decrease of the above loading to the needed values of ≤ 0.1 mgPt cm-2 discussed above is expected to pose a challenge in terms of high current density operation due to limitation in the transport of reactants (oxygen and protons) to such a reduced catalyst area[2]. Part of this performance loss includes the transport of O2 through the ionomer film that generally covers the Pt nanoparticles in the cathode CL. This O2 transport resistance can be quantified via O2 limiting current measurements through which the non-Fickian, Knudsen diffusion through the CL can be quantified[3]. Thus, in this work we present our results in the manufacture and PEMFC-testing of low loading Pt-Ni aerogel CLs, which we tackled with and without the use of an ionomer and benchmarked against equivalently -loaded CLs prepared with a commercial Pt/C catalyst. Our results unveil a relation between ionomer presence/absence, non-Fickian oxygen transport resistance and roughness factor that is comparable to that reported by Kongkanand and Mathias for unsupported, Pt-based nanostructured thin films[4].In addition to this, aerogel electrodes feature a reduced thickness (≈ 5 μm/(mgPt∙cm− 2) that is likely to result in water flooding and ice accumulation at low temperatures and during cold-starts (< 0˚C), respectively. Under the latter, extreme conditions, the water produced by the reduction of oxygen can form ice, which is expected to accumulate within the cathode pore volume and lead to a high oxygen transport resistance[5]. Moreover, the lack of hydrophobicity and of storage capacity (i.e. void volume) within the catalyst layer is susceptible to cause water flooding and/or ice formation, ultimately leading to cell failure[6]. Thus, this contribution will also showcase our results under such low temperature and cold start conditions (in the latter case, at − 10 °C), and do so while considering the combinations of low vs. high aerogel loadings and presence vs. absence of ionomer discussed above. In doing so, this work will provide a holistic picture of the mass-transport effects determining the performance of these aerogel CLs under automotive-relevant conditions.

Mild and scalable synthesis of phosphonorhodamines.

Since their discovery in 1887, rhodamines have become indispensable fluorophores for biological imaging. Recent studies have extensively explored heteroatom substitution at the 10' position and a variety of substitution patterns on the 3',6' nitrogens. Although 3-carboxy- and 3-sulfono-rhodamines were first reported in the 19th century, the 3-phosphono analogues have never been reported. Here, we report a mild, scalable synthetic route to 3-phosphonorhodamines. We explore the substrate scope and investigate mechanistic details of an exogenous acid-free condensation. Tetramethyl-3-phosphonorhodamine (phosTMR) derivatives can be accessed on the 1.5 mmol scale in up to 98% yield (2 steps). phosTMR shows a 12- to 500-fold increase in water solubility relative to 3-carboxy and 3-sulfonorhodamine derivatives and has excellent chemical stability. Additionally, phosphonates allow for chemical derivatization; esterification of phosTMR facilitates intracellular delivery with localization profiles that differ from 3-carboxyrhodamines. The free phosphonate can be incorporated into a molecular wire scaffold to create a phosphonated rhodamine voltage reporter, phosphonoRhoVR. PhosRhoVR 1 can be synthesized in just 6 steps, with an overall yield of 37% to provide >400 mg of material, compared to a 6-step, ∼2% yield for the previously reported RhoVR 1. PhosRhoVR 1 possesses excellent voltage sensitivity (37% ΔF/F) and a 2-fold increase in cellular brightness compared to RhoVR 1.

Substitusi Mie Sumber Zat Gizi Mikro Bahan Pangan Lokal Lahan Gambut terhadap Daya Terima Balita Underweight Umur 24-59 Bulan

Nutritional problems are still a serious impact on the quality of human resources in Indonesia, especially the problem of double nutrition in children under five. Underweight is one of the serious nutritional problems that need to be addressed in addition to stunting. The handling of undernourished children under five is done by providing additional food (PMT). One of the local ingredients that can be made is dry noodles, which are high in micronutrients. Making noodles can be modified from local ingredients, including yellow sweet potato where sweet potato (Ipomoea batatas L) is a type of tuber that has many advantages. Noodles can be enriched with nutrients by adding micronutrients sourced from local peatlands, namely snakehead fish and red ferns. Snakehead fish has a protein content of 25.2%, and contains albumin 62.24 g/kg (6.22%). While the red fern contains the minerals Calcium and Iron 291.32 mg per 100 mg of material, allowing it to prevent anemia. This study aims to determine the Substitution of Noodles Source of Micronutrients Local Food Ingredients on Peat Land on Nutritional Quality and Acceptability of Underweight Toddlers Age 24-59 Months in the District of Rasau Jaya. The design of this research is pure experimental (true experiment. The number of panelists is 30 people. Statistical test using Friedman statistical test to analyze the differences in substitution of yellow sweet potato, snakehead fish and red fern on organoleptic quality (color, taste, aroma, and texture). Test results acceptability based on the average amount according to color, aroma, taste, and texture on dry noodles as a whole obtained the highest results in treatment 1, namely F1 with a total of 451. The best value was obtained in treatment P1, where the best treatment was the treatment with the highest NP value, namely P1 of 0.78 with the following characteristics: color 3.83 (somewhat like), aroma 3.97 (somewhat like), taste 3.53 (somewhat like), texture 3.53 (somewhat like), Like) Friedman test results showed that there was no effect of the addition of yellow sweet potato, snakehead fish extraction and red fern extraction on d I accept the color, taste, aroma and texture of dry noodles.

Simultaneous Estimation of Gas Adsorption Equilibria and Kinetics of Individual Shaped Adsorbents.

Shaped adsorbents (e.g., pellets, extrudates) are typically employed in several gas separation and sensing applications. The performance of these adsorbents is dictated by two key factors, their adsorption equilibrium capacity and kinetics. Often, adsorption equilibrium and textural properties are reported for materials. Adsorption kinetics are seldom presented due to the challenges associated with measuring them. The overarching goal of this work is to develop an approach to characterize the adsorption properties of individual shaped adsorbents with less than 100 mg of material. To this aim, we have developed an experimental dynamic sorption setup and complemented it with mathematical models, to describe the mass transport in the system. We embed these models into a derivative-free optimizer to predict model parameters for adsorption equilibrium and kinetics. We evaluate and independently validate the performance of our approach on three adsorbents that exhibit differences in their chemistry, synthesis, formulation, and textural properties. Further, we test the robustness of our mathematical framework using a digital twin. We show that the framework can rapidly (i.e., in a few hours) and quantitatively characterize adsorption properties at a milligram scale, making it suitable for the screening of novel porous materials.

Prediction and analysis of EDM performances considering random multiple-pulse discharges based on geometric optimization modeling

Continuous electrical discharge machining (EDM) is characterized by random discharge positions, uncertain discharge energy, extremely short discharge time, extremely narrow tool-workpiece gaps, etc. Theoretical research into the mechanisms leading to thermal erosion of material and the associated surface morphology has become urgent to allow the continued development and application of EDM technology. Firstly, multi-pulse theory and geometric optimization are utilized to derive an expression for the material removal rate and surface roughness in multi-pulse EDM. Secondly, based on the characteristics of multi-pulse discharge, a multi-pulse numerical simulation model was established to predict the material removal volume, surface roughness, and thickness of the recast layer. Finally, the results predicted by the geometric and numerical models are compared with the experimental results. Experimentally, 0.176 mg of material is removed in the multi-pulse EDM; the theoretical calculation and numerical simulation of the same produce errors of 5.11% and 11.36%, respectively. The analogous results for the surface roughness are 1.623 μm, 8.93%, and 1.23%. The experimentally determined thickness of the recast layer was 5.31 μm, which corresponds to an error in the simulation error of 7.53%.

Amphotericin-B-loaded polymer-functionalized reduced graphene oxides for Leishmania amazonensis chemo-photothermal therapy

Two platforms based on reduced graphene oxide (rGO) functionalized with Pluronic® P123 (rGO-P123) and polyethyleneimine – PEI (rGO-PEI) polymers and loaded with amphotericin B (AmB) were fabricated and tested against Leishmania amazonensis, which can cause cutaneous and diffuse cutaneous leishmaniasis. The materials rGO-P123 and rGO-PEI were efficiently loaded with AmB – a polyene antibiotic – which resulted in rGO-P123-AmB (0.078 mg per mg of material) and rGO-PEI-AmB (0.086 mg per mg of material). Under near-infrared (NIR) light irradiation, the amount of AmB released from rGO-PEI-AmB at pH 5.0 and 7.4 doubled in comparison to AmB released in the absence of NIR light under identical conditions. It was accompanied by a photothermal effect. Otherwise, rGO-P123-AmB did not show a significant change in AmB released in the presence and absence of NIR light. Cytotoxicity studies in mammalian host macrophages revealed that rGO-PEI and rGO-PEI-AmB were nontoxic to the host cells, whereas rGO-123 and rGO-P123-AmB were very toxic, particularly the latter. Therefore, only rGO-PEI and rGO-PEI-AmB were tested against L. amazonensis promastigotes in the presence and absence of NIR light. In vitro antiproliferative effects revealed that rGO-PEI-AmB showed a more pronounced activity against the parasite than rGO-PEI, which was improved under NIR light irradiation. Scanning-transmission electron microscopy of L. amazonensis promastigotes after incubation with rGO-PEI or rGO-PEI-AmB suggested autophagic and necrotic cell death. Thus, the facile synthesis, high AmB loading capacity and good photothermal effect make the rGO-PEI-AmB platform a promising candidate for the topical treatment of cutaneous leishmaniasis.

A microcapillary rheometer for microliter sized polymer characterization

We report the design of a microcapillary rheometer (μCR) that allows to perform experiments rapidly and in a broad range of shear rates (i.e., from 0.1 to 1000 s−1), using small amounts of material (i.e., just few milligrams). Additionally, multiple measurement parallelization makes it suitable for High-Throughput Rheological Experimentation of polymer melts (HT-Rheo-E).The novel rheometer consists of a set of three cylindrical microcapillaries in which the fluid flows driven by a controlled pressure. A camera, placed at the capillary exit, records the fluid motion to measure its flow rate, from which the fluid viscosity can be determined. The optimization of the setup allowed for reliable and fast viscosity measurements using ca. 10 mg of material. The current work reports the design of the rheometer and validation measurements on several model fluids. The microfabricated μCR is of potential interest for applications in quality control and research where rapid and repeated measurements using limited milligrams of polymer are required, as well as for High-Throughput-Experimentation of complex fluids (e.g., biological systems).

Bronzealderens hjortetaksøkser – datering og deponeringsforhold

Breonze Age antler axes – dating and depositional context&#x0D; Antler axes are typically associated with the Mesolithic, but this article presents a group of antler axes from the Danish Bronze Age, when this artefact type surprisingly turns up again after an absence from the tool inventory of more than 2000 years (fig. 1).&#x0D; These artefacts may be found in pits in a settlement context, but the typical finds contexts for the 155 recorded Bronze Age antler axes are rivers/watercourses, lakes and wetland areas, where the axes have been deposited individually, in line with the Bronze Age’s other major group of singly-deposited objects (figs. 2-3). This close relationship with water is linked to the European river finds, as antler axes are not solely a Danish phenomenon but are found across large parts of Europe during the Bronze Age, with the axes typically being deposited singly in running water. In both a Danish and a European context, the axes disappear again in the Iron Age.&#x0D; This article gives an account of the Danish antler axes in relation to their distribution, finds circumstances and typo­logical characteristics, together with a couple of metal analyses and several new 14C dates for antler axes. The antler axes from the Bronze Age vary in appearance; they may or may not be polished and may or may not be ornamented. They do though have certain features in common, for example they are characterised by a down-turned butt. The shaft-hole can either be round or rectangular and is located a long way back on the axe. They were typically hafted as axes rather than adzes, and their ornamentation frequently consists of point-circle motifs, where pitch has been inlaid to give contrast (figs. 4-8). In a very few cases, metal may form part of the ornamentation. Two results are presented here of micro-XRF analyses of, respectively, inlays of tin and bronze (figs. 9-14).&#x0D; A significant part of the project ­focussed on dating of the Bronze Age antler axes. Only a couple of dates had been published previously, both of which fell in the Late Bronze Age. The new dates clearly show, however, that antler axes are a very consistent phenomenon through both the Early and the Late Bronze Age. Dating involves drilling material out for analysis, and in the case of antler and bone there is sometimes a requirement for a sample of as much as 600-800 mg for a date to be obtained. To avoid drilling unnecessary holes in the often aesthetically impressive and eminently exhibitable artefacts such as these, a staged methodological approach was adopted in this project, which involved two-step sampling for radiocarbon dating. Firstly, a very small sample of 5-20 mg was taken for a so-called EA-IRMS analysis. This reveals the preservation condition of the material and thereby the amount of material required to obtain an actual 14C date. In all cases, this preliminary analysis showed that only 100 mg of material had to be drilled out for the actual dating process. This method can therefore be warmly recommended for the dating of bone and antler objects such as these (figs. 15-16).&#x0D; The dates have revealed that antler axes are present in both the Early and the Late Bronze Age. Moreover, the dates could be used in a clarification of the depositional circumstances. As already mentioned, the antler axes typically represent single depositions, but sometimes two axes are found relatively close together and, based on the finds circumstances, are therefore interpreted as single-type depositions. It has now been possible in some cases to date both axes: For example antler axes found together in sediment dug up during the dredging of rivers/watercourses (Ryå and Odense Å), or discovered close together during peat cutting (Jorløse Mose) or within the same area of reclaimed lake (Søborg Sø). The dates obtained in these cases suggest that these finds represent repeated single depositions within the same area rather than simultaneous deposition of two axes. The phenomenon of returning, in a depositional context, to specific areas in the natural landscape, sometimes at intervals of several hundred years, appears to be a general feature of the Bronze Age – both in Denmark and in Europe as a whole (figs. 17a-22).

Beyond Ternary OPV: High-Throughput Experimentation and Self-Driving Laboratories Optimize Multicomponent Systems.

Fundamental advances to increase the efficiency as well as stability of organic photovoltaics (OPVs) are achieved by designing ternary blends, which represents a clear trend toward multicomponent active layer blends. The development of high-throughput and autonomous experimentation methods is reported for the effective optimization of multicomponent polymer blends for OPVs. A method for automated film formation enabling the fabrication of up to 6048 films per day is introduced. Equipping this automated experimentation platform with a Bayesian optimization, a self-driving laboratory is constructed that autonomously evaluates measurements to design and execute the next experiments. To demonstrate the potential of these methods, a 4D parameter space of quaternary OPV blends is mapped and optimized for photostability. While with conventional approaches, roughly 100 mg of material would be necessary, the robot-based platform can screen 2000 combinations with less than 10 mg, and machine-learning-enabled autonomous experimentation identifies stable compositions with less than 1 mg.

Miniaturized characterization of polymers: From synthesis to rheological and mechanical properties in 30 mg

The determination of rheological and mechanical material properties becomes a challenge when the availability of material is limited to a few (milli)grams. This miniaturized testing is hampered by the contradicting requirements of small sample sizes (and thus surface areas) and sufficiently large generated torques and forces. In this paper we provide a feasible methodology to determine the relevant material parameters in terms of processing and mechanical performance starting from 30 mg of material, using micropillars with a diameter of 1 mm. Complex viscosity in small amplitude oscillatory shear as the relevant parameter for thermoconformation processes is determined by means of eccentric rheometry. Herein, the sample is placed off-centered, which results in an increase in the generated torque without the need for increasing the size of the sample. By combining experimental data and numerical simulations, we show that the choice of the pillar aspect ratio is essential to maintain a homogeneous sample deformation and thus to extract correct rheological parameters. Values obtained with eccentric rheometry collapse with those obtained from standard rheometry. The intrinsic mechanical behavior is evaluated at room temperature and the yielding kinetics is studied. The methodology developed here can be extended to other systems and testing conditions, allowing a full material characterization in the liquid as well as in the solid state with only 30 mg of material.

Scalable Total Synthesis of (-)-Vinigrol.

Vinigrol is a structurally and stereochemically complex natural product that displays various potent pharmacological activities, including the capability to modulate TNF-α. A new and efficient synthetic route toward this natural product has been developed to complete the asymmetric synthesis of (-)-vinigrol and provide over 600 mg of material, manifesting the power of macrocyclic stereocontrol and transannular Diels-Alder reaction.

Probing O-H Bonding through Proton Detected 1H-17O Double Resonance Solid-State NMR Spectroscopy.

The ubiquity of oxygen in organic, inorganic, and biological systems has stimulated the application and development of 17O solid-state NMR spectroscopy as a probe of molecular structure and dynamics. Unfortunately, 17O solid-state NMR experiments are often hindered by a combination of broad NMR signals and low sensitivity. Here, it is demonstrated that fast MAS and proton detection with the D-RINEPT pulse sequence can be generally applied to enhance the sensitivity and resolution of 17O solid-state NMR experiments. Complete 2D 17O → 1H D-RINEPT correlation NMR spectra were typically obtained in less than 10 h from less than 10 mg of material, with low to moderate 17O enrichment (less than 20%). Two-dimensional 1H-17O correlation solid-state NMR spectra allow overlapping oxygen sites to be resolved on the basis of proton chemical shifts or by varying the mixing time used for 1H-17O magnetization transfer. In addition, J-resolved or separated local field (SLF) blocks can be incorporated into the D-RINEPT pulse sequence to allow the direct measurement of one-bond 1H-17O scalar coupling constants (1 JOH) or 1H-17O dipolar couplings ( DOH), respectively, the latter of which can be used to infer 1H-17O bond lengths. 1 JOH and DOH calculated from plane-wave density functional theory (DFT) show very good agreement with experimental values. Therefore, the 2D 1H-17O correlation experiments, 1H-17O scalar and dipolar couplings, and plane-wave DFT calculations provide a method to precisely determine proton positions relative to oxygen atoms. This capability opens new opportunities to probe interactions between oxygen and hydrogen in a variety of chemical systems.

Limits of Resolution and Sensitivity of Proton Detected MAS Solid-State NMR Experiments at 111 kHz in Deuterated and Protonated Proteins

MAS solid-state NMR is capable of determining structures of protonated solid proteins using proton-detected experiments. These experiments are performed at MAS rotation frequency of around 110 kHz, employing 0.5 mg of material. Here, we compare 1H, 13C correlation spectra obtained from protonated and deuterated microcrystalline proteins at MAS rotation frequency of 111 kHz, and show that the spectral quality obtained from deuterated samples is superior to those acquired using protonated samples in terms of resolution and sensitivity. In comparison to protonated samples, spectra obtained from deuterated samples yield a gain in resolution on the order of 3 and 2 in the proton and carbon dimensions, respectively. Additionally, the spectrum from the deuterated sample yields approximately 2–3 times more sensitivity compared to the spectrum of a protonated sample. This gain could be further increased by a factor of 2 by making use of stereospecific precursors for biosynthesis. Although the overall resolution and sensitivity of 1H, 13C correlation spectra obtained using protonated solid samples with rotation frequencies on the order of 110 kHz is high, the spectral quality is still poor when compared to the deuterated samples. We believe that experiments involving large protein complexes in which sensitivity is limiting will benefit from the application of deuteration schemes.

A comparison of occupational exposure limits and their relationship to reactive oxide species

A heuristic approach to estimating toxicity and controlling exposure to emerging materials has been developed based on the amount of luminol reactive species present. Relative light units (measured with luminometer) per mg of material measured in a bulk sample are used as the measure of reactive oxide species and subsequent oxidative stress potential. Reactive oxide species are determined per unit of mass for a series of pneumoconiosis producing materials with established exposure limits as a reference. Values presented are dependent on the specific luminometer used to make the measurements and should not be considered as absolute. The materials tested in powder form included crystalline silica, titanium dioxide, aluminum, talc, graphite, wollastonite, and ferric oxide. Relative light units regressed on exposure limit was high when the exposure limit was low (Spearman’s rho = −0.8921, p < 0.01).Measurement of the ROS of a material without an exposure limit may be used as a justification to limit potential respirable dust hazards utilizing control banding, administrative controls or identifying respiratory protection. A comparison such as this provides an informed basis for meaningful hazard analyses in the absence of established exposure guidelines, and may be more justifiable than assignment to the Particles Not Otherwise Specified TLV® category.

Influence of sample cleaning prior to the analysis on the elemental content of the lichen Xanthoria parietina (L.) Th.Fr.

In this paper we investigated whether a different accuracy in sample cleaning prior to the analysis may affect the elemental composition of unwashed samples of the lichen Xanthoria parietina. To this purpose, samples of this lichen were collected from a remote area of Sardinia (Italy) and randomly divided into two aliquots, one cleaned very carefully (ca. 3-4 h to obtain ca. 200 mg of material for analysis) and the other cleaned with a lower efficiency (ca. 1-2 h). Samples were analysed by ICP-MS for the content of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, V and Zn. The results indicated that an accurate cleaning is effective for reducing the content of Al and Fe, i.e. soil-related elements, but that it has no effect on the concentrations of other elements less represented in the soil.

High-Throughput Quantitative Biochemical Characterization of Algal Biomass by NIR Spectroscopy; Multiple Linear Regression and Multivariate Linear Regression Analysis

One of the challenges associated with microalgal biomass characterization and the comparison of microalgal strains and conversion processes is the rapid determination of the composition of algae. We have developed and applied a high-throughput screening technology based on near-infrared (NIR) spectroscopy for the rapid and accurate determination of algal biomass composition. We show that NIR spectroscopy can accurately predict the full composition using multivariate linear regression analysis of varying lipid, protein, and carbohydrate content of algal biomass samples from three strains. We also demonstrate a high quality of predictions of an independent validation set. A high-throughput 96-well configuration for spectroscopy gives equally good prediction relative to a ring-cup configuration, and thus, spectra can be obtained from as little as 10-20 mg of material. We found that lipids exhibit a dominant, distinct, and unique fingerprint in the NIR spectrum that allows for the use of single and multiple linear regression of respective wavelengths for the prediction of the biomass lipid content. This is not the case for carbohydrate and protein content, and thus, the use of multivariate statistical modeling approaches remains necessary.

Experimental Screening of Porous Materials for High Pressure Gas Adsorption and Evaluation in Gas Separations: Application to MOFs (MIL-100 and CAU-10)

A high-throughput gas adsorption apparatus is presented for the evaluation of adsorbents of interest in gas storage and separation applications. This instrument is capable of measuring complete adsorption isotherms up to 40 bar on six samples in parallel using as little as 60 mg of material. Multiple adsorption cycles can be carried out and four gases can be used sequentially, giving as many as 24 adsorption isotherms in 24 h. The apparatus has been used to investigate the effect of metal center (MIL-100) and functional groups (CAU-10) on the adsorption of N(2), CO(2), and light hydrocarbons on MOFs. This demonstrates how it can serve to evaluate sample quality and adsorption reversibility, to determine optimum activation conditions and to estimate separation properties. As such it is a useful tool for the screening of novel adsorbents for different applications in gas separation, providing significant time savings in identifying potentially interesting materials.