Molecular Content Research Articles

A local polynomial moment approximation for compartmentalized biochemical systems

Compartmentalized biochemical reactions are a ubiquitous building block of biological systems. The interplay between chemical and compartmental dynamics can drive rich and complex dynamical behaviors that are difficult to analyze mathematically — especially in the presence of stochasticity. We have recently proposed an effective moment equation approach to study the statistical properties of compartmentalized biochemical systems. So far, however, this approach is limited to polynomial rate laws and moreover, it relies on suitable moment closure approximations, which can be difficult to find in practice. In this work we propose a systematic method to derive closed moment dynamics for compartmentalized biochemical systems. We show that for the considered class of systems, the moment equations involve expectations over functions that factorize into two parts, one depending on the molecular content of the compartments and one depending on the compartment number distribution. Our method exploits this structure and approximates each function with suitable polynomial expansions, leading to a closed system of moment equations. We demonstrate the method using three systems inspired by cell populations and organelle networks and study its accuracy across different dynamical regimes.

Quantitative Label-Free Mass Spectrometry Identifies Molecular Content and Signaling Differences between Neonatal and Adult Platelets

Observational and randomized studies have associated platelet transfusions with increased morbidity and mortality in preterm neonates. Clinical practice changes have been hindered by a limited understanding of why adult donor-derived platelets might be inappropriate or harmful to infants. Neonatal and adult platelets differ in reactivity and function, but we lack an understanding of underlying molecular differences. As proteins and kinase-driven phosphorylation signaling dictate platelet biology, we aimed to characterize altered protein and phosphoprotein content between neonatal and adult platelets to help explain differences in platelet reactivity and function. We isolated resting platelets from full term cord blood (n=9) and adult peripheral blood (n=7) and used mass spectrometry-based platforms to ascertain protein and phosphoprotein content. We identified 4745 high-confidence proteins in adult and neonatal platelets, including 331 differentially abundant proteins (≥1.5-fold change, p<0.05). Neonatal platelets had increased metabolic and ribosomal proteins, consistent with transcriptional data. Adult platelets were enriched for inflammatory proteins, including complement components, consistent with pro-inflammatory function. We also identified 2115 phospho-proteins (17852 unique phosphopeptides) across all samples. These impacted actin cytoskeletal biology, cell adhesion, and GTPase signaling that regulate platelet functions. Kinase enrichment analysis identified FYN, SRC, ABL1, and AKT1 as kinases most responsible for platelet phosphorylation activities. Granule trafficking and degranulation proteins were among 1183 differentially abundant phosphoproteins in neonatal vs adult samples (p<0.05). For example, 31 different Reticulon 1 (RTN1) phosphopeptides were enriched in adult platelets (p<0.05). RTN1 regulates membrane trafficking and participates in SNARE-mediated exocytosis. Increased RTN1-directed membrane trafficking may promote increased activation and degranulation in adult vs neonatal platelets. Indeed, SNARE complex protein deficiency was previously suggested to mediate hyporeactive degranulation in neonatal platelets. We detected 2 phosphopeptides in adult samples that were absent from any neonatal sample. We reasoned that these could represent developmental stage-specific differences that exist only in adult platelets. One of the adult-specific phosphopeptides was in Rap1GAP2 (phospho-S588). Rap1GAP2 is a highly phosphorylated GTPase-activating protein that inhibits Rap1, a small guanine-nucleotide-binding protein that facilitates integrin activation in platelets. Rap1GAP2 binds synaptotagmin-like protein 1 (Slp1) to regulate dense granule secretion. These findings may link altered developmentally regulated Rap1GAP2 activities with platelet degranulation. A Platelet Cell Adhesion Molecule (PECAM) phosphopeptide (phospho-S726) was also found exclusively in adult platelets. PECAM facilitates inflammation and leukocyte transendothelial migration. PECAM phosphorylation in adult platelets may reflect an enhanced ability to participate in these processes. These findings reveal key differences in protein content and signaling that underlie differential neonatal vs adult platelet reactivity and function, including pro-inflammatory activities and enhanced activation and/or degranulation propensity in adult platelets. RTN1-mediated SNARE complex function and Rap1 signaling activities represent novel and potentially modifiable targets to manipulate platelet activation and/or degranulation. Our results also help provide a biological rationale for the higher morbidity and mortality observed in preterm infants transfused with adult platelets, including the inadvertent introduction of serum complement and other pro-inflammatory molecules within transfusions of donated adult platelets.

Study on the Effect of Monoacrylic Monomers on the Polymer Network Morphology and Electro-Optical Performance of Reverse-Mode Polymer Stabilized Liquid Crystal Devices

A polymer-stabilized liquid crystal (PSLC) device has been a promising candidate in several scenarios like smart vehicle windows and glass curtain walls in recent years due to its remarkable features like a fast switch from the initial transparent state to the scattering state with a rather low driving voltage, high transmittance at off-state, and broad viewing angle. The electro-optical characteristics of PSLC devices are determined by the synergistic attributions of liquid crystal (LC) molecules and the influence of the polymer network exerted on the movement of LC molecules. A systematic study of the influence of the polymer network on the movement of LC molecules is conducted, with the polymer network formed by methoxy/cyano/carboxyl monomers and diacrylate C6M. The polymer network morphology of PSLC film is greatly affected by the molecular structures and content of monoacrylic monomers. Additionally, the electro-optical performance and peel strength of PSLC films could be improved by modulating the molecular structures and morphology of polymer networks. PSLC devices containing carboxyl monomers show enhanced electro-optical performance and peel strength due to their directional filiform topology. This study might provide guidance for optimizing the performance of PSLC devices and establishing the relationship between the molecular structure, polymer network morphology, and electro-optical performance of reverse-mode dimming films.

Testing the effectiveness of different wash protocols to remove body surface contaminants in invertebrate food web studies.

Molecular gut content analysis via diagnostic PCR or high-throughput sequencing (metabarcoding) of consumers allows unravelling of feeding interactions in a wide range of animals. This is of particular advantage for analyzing the diet of small invertebrates living in opaque habitats such as the soil. Due to their small body size, which complicates dissection, microarthropods are subjected to whole-body DNA extraction-step before their gut content is screened for DNA of their food. This poses the problem that body surface contaminants, such as fungal spores may be incorrectly identified as ingested food particles for fungivorous species. We investigated the effectiveness of ten methods for body surface decontamination in litter-dwelling oribatid mites using Steganacarus magnus as model species. Furthermore, we tested for potential adverse effects of the decontamination techniques on the molecular detection of ingested prey organisms. Prior to decontamination, oribatid mites were fed with an oversupply of nematodes (Plectus sp.) and postmortem contaminated with fungal spores (Chaetomium globosum). We used diagnostic PCR with primers specific for C. globosum and Plectus sp. to detect contaminants and prey, respectively. The results suggest that chlorine bleach (sodium hypochloride, NaClO, 5%) is most efficient in removing fungal surface contamination without significantly affecting the detection of prey DNA in the gut. Based on these results, we provide a standard protocol for efficient body surface decontamination allowing to trace the prey spectrum of microarthropods using molecular gut content analysis.

Machine learning-based analysis of cancer cell-derived vesicular proteins revealed significant tumor-specificity and predictive potential of extracellular vesicles for cell invasion and proliferation – A meta-analysis

BackgroundAlthough interest in the role of extracellular vesicles (EV) in oncology is growing, not all potential aspects have been investigated. In this meta-analysis, data regarding (i) the EV proteome and (ii) the invasion and proliferation capacity of the NCI-60 tumor cell lines (60 cell lines from nine different tumor types) were analyzed using machine learning methods.MethodsOn the basis of the entire proteome or the proteins shared by all EV samples, 60 cell lines were classified into the nine tumor types using multiple logistic regression. Then, utilizing the Least Absolute Shrinkage and Selection Operator, we constructed a discriminative protein panel, upon which the samples were reclassified and pathway analyses were performed. These panels were validated using clinical data (n = 4,665) from Human Protein Atlas.ResultsClassification models based on the entire proteome, shared proteins, and discriminative protein panel were able to distinguish the nine tumor types with 49.15%, 69.10%, and 91.68% accuracy, respectively. Invasion and proliferation capacity of the 60 cell lines were predicted with R2 = 0.68 and R2 = 0.62 (p < 0.0001). The results of the Reactome pathway analysis of the discriminative protein panel suggest that the molecular content of EVs might be indicative of tumor-specific biological processes.ConclusionIntegrating in vitro EV proteomic data, cell physiological characteristics, and clinical data of various tumor types illuminates the diagnostic, prognostic, and therapeutic potential of EVs.7aedpy9z2qaEGFgoHMHH1UVideo

Process optimization and effect of different extraction methods on the characteristics and activities of Herba Patriniae polysaccharides: A correlation analysis

The process of papain assisted hot water (WP), cellulase assisted hot water (WC), papain mixed cellulase assisted hot water (WPC), ultrasonic assisted papain (PU), and ultrasonic assisted cellulase (CU) for Patriniae polysaccharides (HPs) extraction were optimized using the indicate of polysaccharide yield, respectively. Then, the physicochemical characteristics, antioxidant and hypoglycemic activities of HPs were compared, with an additional correlation analysis between the characteristics and activities of HPs. The results showed that CU demonstrated the highest extraction rate at 30.50 % among all methods. Compared to previous hot water extraction (HW), the enzyme-assisted extraction increased molecular weight, reducing sugar, mannose, and glucose content of HPs, while ultrasound-assisted extraction lowered mannose and glucose content of HPs, and increased reducing sugar content of HPs. All HPs showed concentration-dependent hypoglycemic and antioxidant activities. Correlation analysis revealed that HPs with moderate galactose content, higher reducing sugar, protein, glucose, mannose, xylose, and molecular weight polysaccharide content would exhibit superior hypoglycemic and antioxidant activities, with CU-HPs expressing these excellent characteristics. Together with the exceptional polysaccharide yield, CU was a promising strategy to extract HPs, whose optimum process were: enzyme addition 2.5 %, solid–liquid ratio 1:25, ultrasonic power 150 W, ultrasonic time of 50 min.

Depolymerisation of Kraft Lignin by Tailor-Made Alkaliphilic Fungal Laccases.

Lignins released in the black liquors of kraft pulp mills are an underutilised source of aromatics. Due to their phenol oxidase activity, laccases from ligninolytic fungi are suitable biocatalysts to depolymerise kraft lignins, which are characterised by their elevated phenolic content. However, the alkaline conditions necessary to solubilise kraft lignins make it difficult to use fungal laccases whose activity is inherently acidic. We recently developed through enzyme-directed evolution high-redox potential laccases active and stable at pH 10. Here, the ability of these tailor-made alkaliphilic fungal laccases to oxidise, demethylate, and depolymerise eucalyptus kraft lignin at pH 10 is evidenced by the increment in the content of phenolic hydroxyl and carbonyl groups, the methanol released, and the appearance of lower molecular weight moieties after laccase treatment. Nonetheless, in a second assay carried out with higher enzyme and lignin concentrations, these changes were accompanied by a strong increase in the molecular weight and content of β-O-4 and β-5 linkages of the main lignin fraction, indicating that repolymerisation of the oxidised products prevails in one-pot reactions. To prevent it, we finally conducted the enzymatic reaction in a bench-scale reactor coupled to a membrane separation system and were able to prove the depolymerisation of kraft lignin by high-redox alkaliphilic laccase.

Multimode vibrational dynamics and orientational effects in fluorescence-encoded infrared spectroscopy. II. Analysis of early-time signals.

Developing fluorescence-encoded infrared (FEIR) vibrational spectroscopy for single-molecule applications requires a detailed understanding of how the molecular response and external experimental parameters manifest in the detected signals. In Paper I [L. Whaley-Mayda, A. Guha, and A. Tokmakoff, J. Chem. Phys. 159, 194201 (2023)] we introduced a nonlinear response function theory to describe vibrational dynamics, vibronic coupling, and transition dipole orientation in FEIR experiments with ultrashort pulses. In this second paper, we apply the theory to investigate the role of intermode vibrational coherence, the orientation of vibrational and electronic transition dipoles, and the effects of finite pulse durations in experimental measurements. We focus on measurements at early encoding delays-where signal sizes are largest and therefore of most value for single-molecule experiments, but where many of these phenomena are most pronounced and can complicate the appearance of data. We compare experiments on coumarin dyes with finite-pulse response function simulations to explain the time-dependent behavior of FEIR spectra. The role of the orientational response is explored by analyzing polarization-dependent experiments and their ability to resolve relative dipole angles in the molecular frame. This work serves to demonstrate the molecular information content of FEIR experiments, and develop insight and guidelines for their interpretation.

Vitamin D modulates disordered lipid metabolism in zebrafish (Danio rerio) liver caused by exposure to polystyrene nanoplastics

In this study, zebrafish (Danio rerio) were exposed to polystyrene nanoplastics (PS-NPs, 80 nm) at 0, 15, or 150 μg/L for 21 days and supplied with a low or high vitamin D (VD) diet (280 or 2800 IU/kg, respectively, indicated by – or +) to determine whether and how VD can regulate lipid metabolism disorder induced by PS-NPs. Six groups were created according to the PS-NP concentration and VD diet status: 0−, 0+, 15−, 15+,150−, and 150 +. Transmission electron microscopy showed that PS-NPs accumulated in the livers of zebrafish, which led to large numbers of vacuoles and lipid droplets in liver cell matrices; this accumulation was most prominent in the 150− group, wherein the number of lipid droplets increased significantly by 136.36%. However, the number of lipid droplets decreased significantly by 76.92% in the 150+ group compared with the 150− group. An examination of additional biochemical indicators showed that the high VD diet partially reversed the increases in the triglyceride and total cholesterol contents induced by PS-NPs (e.g., triglycerides decreased by 58.52% in the 150+ group, and total cholesterol decreased by 44.64% in the 15+ group), and regulated lipid metabolism disorder mainly by inhibiting lipid biosynthesis. Untargeted lipidomics analysis showed that exposure to PS-NPs was associated mainly with changes in the lipid molecular content related to cell membrane function and lipid biosynthesis and that the high VD diet reduced the content of lipid molecules related to lipid biosynthesis, effectively alleviating cell membrane damage and lipid accumulation. These findings highlight the potential of VD to alleviate lipid metabolism disorder caused by PS-NP exposure, thereby providing new insights into how the toxic effects of NPs on aquatic organisms could be reduced.

How will climate change affect the feeding biology of Collembola?

Collembolans are one of the most diverse and abundant group of soil invertebrates. Recent studies have shown anthropogenic climate warming to alter Collembola diversity and density in warm-dry (more detrimental effects) and warm-wet (lesser detrimental effects) conditions. Besides the direct influence of abiotic stressors, shifts in food availability could help understand variable collembolan responses to climate warming. Collembolan diet is generally formed by two main groups of soil fungi: saprotrophic and mycorrhizal fungi, which occupy different spatial niches in the soil, and are simultaneously affected by climate warming and drought. These fungal responses to climate change alter food availability for Collembola, inducing shifts in their dietary composition. Collembolans preferentially consume saprotrophic fungi, regardless of their spatial niche. However, those inhabiting deeper soil layers occasionally feed on mycorrhizal fungi and rely more frequently on such diets when other food sources become scarce. We suggest that climate change-driven scarcity of saprotrophic fungal diets in soils would make collembolans depend more on mycorrhizal fungal diets. We then discuss how such dietary shifts are driven by distinct mechanisms in warm-dry and warm-wet soil conditions. We finally call for the use of emerging techniques (e.g., stable isotope analysis, molecular gut content) to quantify the diets of Collembola more accurately under different climate change scenarios, which will help us shed more insights on how warming and precipitation variability are going to alter Collembola-fungal trophic interactions in a changing world.

Fabrication and evaluation of novel amphiphilic star block copolymers for increasing free water content in lignite to make coal water slurries

In order to reduce the apparent viscosity of lignite coal water slurries (CWSs) and improve its static stability, a series of three-arm amphiphilic block copolymers have been prepared through RAFT polymerization by using poly(ethylene glycol) methyl ether acrylate (PEGMA) and sodium 4-vinylbenzenesulfonate (SSNa) as hydrophilic monomers and styrene (St) as hydrophobic monomer. The chemical structure of the copolymers has been investigated, and the impact of relative molecular weight, hydrophilic/hydrophobic ratio, and ionic group content on the pulping performance of three-arm amphiphilic block copolymers has been examined. The lignite coal water slurries (CWSs) prepared from the block copolymer tri-P(St50-s-SSNa50)10K-b-PPEGMA10K exhibit a remarkably low apparent viscosity of 395 mPa·s and excellent static stability when the coal content is at 55 wt% and dispersant content is at 0.5 wt%. Moreover, these CWSs can achieve a maximum pulping concentration of up to 59 wt%. Additionally, the thermogravimetric test reveals insights into the water occurrence in CWSs, indicating that higher levels of free water content correspond to lower apparent viscosities. Suitable hydrophobicity facilitates the removal of internal water from lignite by dispersants, disrupting its flocculation structure and promoting CWSs formation. Meanwhile, the presence of ionic groups enhances the static stability of the resulting CWSs. Furthermore, the adsorption behavior of the three-arm amphiphilic block copolymer dispersant in lignite has been analyzed through XPS testing to elucidate its dispersion mechanism. The use of three-arm amphiphilic block copolymers in preparing lignite CWSs results in lower apparent viscosity and improved static stability, attributed to the amphiphilic and steric hindrance effects of dispersants. This not only expands the application range of lignite CWSs but also highlights the significant potential of this type of dispersant.

Poly(Siloxane–Propylene Oxide–Urethane–Ureas) Based on Cycloaliphatic Diisocyanates: Synthesis and Properties

New network poly(siloxane–propylene oxide–urethane–ureas) based on α,ω-bis[(3-aminopropyl)diethoxy]oligodimethylsiloxanes, oligo(propylene oxide), and cycloaliphatic diisocyanates are synthesized. The resulting polymers are studied by differential scanning calorimetry and thermogravimetric analysis; their stress–strain characteristics are elucidated. These polymers are found to feature microphase separation and, consequently, two glass transition temperatures, defined by the chemical structures of the microphases. It is shown that an increase in the molecular weight and mass content of siloxane blocks leads to a decrease in the elastic modulus and tensile strength.

Novel insights into the effects of asphaltenes on oil phase properties: Crude oil, oil-water interface, and graphene oxide synergistic demulsification

In this work, quantum chemical calculations and molecular dynamics simulations were employed to investigate the aggregation structure of asphaltene (a key component in heavy oil) and the influence of its molecular structure and content on the viscosity of heavy oil. Research suggests that the C5Pe molecules have a strong potential to bind together through π-π interactions (face-to-face). The angle between the two plane normal vectors was 1.4°. The mechanism of asphaltene-oil phase assembly can be succinctly summarized as the “rebar-cement” mode of action. The viscosity of heavy oil increases with the increase of asphaltenes, which can be attributed to the more complete construction of the three-dimensional network structure of asphaltene with the increase of asphaltene mass fraction (especially exceeding 35 wt%). The steered molecular dynamics simulation confirmed that reducing the concentration of asphaltenes in emulsified heavy oil droplets leads to increased susceptibility to mechanical destruction. This observation implies that asphaltenes negatively impact the demulsification and viscosity reduction of crude oil. The findings in this work can contribute to the development of efficient strategies for viscosity control and enhanced production of heavy oil resources.

Extracellular Vesicles altered by a Per- and Polyfluoroalkyl Substance Mixture: In Vitro Dose-Dependent Release, Chemical Content, and MicroRNA Signatures involved in Liver Health.

Per- and polyfluoroalkyl substances (PFAS) have emerged as high priority contaminants due to their ubiquity and pervasiveness in the environment. Numerous PFAS co-occur across sources of drinking water, including areas of North Carolina (NC) with some detected concentrations above the Environmental Protection Agency's health advisory levels. While evidence demonstrates PFAS exposure induces harmful effects in the liver, the involvement of extracellular vesicles (EVs) as potential mediators of these effects has yet to be evaluated. This study set out to evaluate the hypothesis that PFAS mixtures induce dose-dependent release of EVs from liver cells, with exposures causing differential loading of microRNAs (miRNAs) and PFAS chemical signatures. To test this hypothesis, a defined PFAS mixture was prioritized utilizing data collected by the NC PFAS Testing Network. This mixture contained three substances, PFOS, PFOA, and PFHxA, selected based upon co-occurrence patterns and the inclusion of both short-chain (PFHxA) and long-chain (PFOA and PFOS) substances. HepG2 liver cells were exposed to equimolar PFAS, and secreted EVs were isolated from conditioned media and characterized for count and molecular content. Exposures induced a dose-dependent release of EVs carrying miRNAs that were differentially loaded upon exposure. These altered miRNA signatures were predicted to target mRNA pathways involved in hepatic fibrosis and cancer. Chemical concentrations of PFOS, PFOA, and PFHxA were also detected in both parent HepG2 cells and their released EVs, specifically within a 15-fold range after normalizing for protein content. This study therefore established EVs as novel biological responders and measurable endpoints for evaluating PFAS-induced toxicity.

Collisional Relaxation of Highly Vibrationally Excited Acetylene Mediated by the Vinylidene Isomer.

Collisional relaxation of highly vibrationally excited acetylene, generated from the 193 nm photolysis of vinyl bromide with roughly 23,000 cm-1 of nascent vibrational energy, is studied via submicrosecond time-resolved Fourier transform infrared (FTIR) emission spectroscopy. IR emission from vibrationally hot acetylene during collisional relaxation by helium, neon, argon, and krypton rare-gas colliders is recorded and analyzed to deduce the acetylene energy content as a function of time. The average energy lost per collision, ⟨ΔE⟩, is computed using the Lennard-Jones collision frequency. Two distinct vibrational-to-translational (V-T) energy transfer regimes in terms of the acetylene energy are identified. At vibrational energies below 10,000-14,000 cm-1, energy transfer efficiency increases linearly with molecular energy content and is in line with typical V-T behavior in quantity. In contrast, above 10,000-14,000 cm-1, the V-T energy transfer efficiency displays a dramatic and rapid increase. This increase is nearly coincident with the acetylene-vinylidene isomerization limit, which occurs nearly 15,000 cm-1 above the acetylene zero-point energy. Combined quasi-classical trajectory calculations and Schwartz-Slawsky-Herzfeld-Tanczos theory point to a vinylidene contribution being responsible for the large enhancement. This observation illustrates the influence of energetically accessible structural isomers to greatly enhance the energy transfer rates of highly vibrationally excited molecules.

The Quasar Feedback Survey: characterizing CO excitation in quasar host galaxies

ABSTRACT We present a comprehensive study of the molecular gas properties of 17 Type 2 quasars at z &amp;lt; 0.2 from the Quasar Feedback Survey (L$_{\rm [O~{\small III}]}$ &amp;gt; 1042.1 $\rm ergs^{-1}$), selected by their high [O iii] luminosities and displaying a large diversity of radio jet properties, but dominated by LIRG-like galaxies. With these data, we are able to investigate the impact of AGN and AGN feedback mechanisms on the global molecular interstellar medium. Using Atacama Pathfinder EXperiment and ALMA ACA observations, we measure the total molecular gas content using the CO(1-0) emission and homogeneously sample the carbon monoxide (CO) spectral line energy distributions, observing CO transitions (Jup = 1, 2, 3, 6, 7). We observe high r21 ratios (r21 = L’CO(2-1)/L’CO(1-0)) with a median r21 = 1.06, similar to local (U)LIRGs (with r21 ∼ 1) and higher than normal star-forming galaxies (with r21 ∼ 0.65). Despite the high r21 values, for the seven targets with the required data, we find low excitation in CO(6-5) &amp; CO(7-6) (r61 and r62 &amp;lt; 0.6 in all but one target), unlike high-redshift quasars in the literature, which are far more luminous and show higher line ratios. The ionized gas traced by [O iii] exhibits systematically higher velocities than the molecular gas traced by CO. We conclude that any effects of quasar feedback (e.g. via outflows and radio jets) do not have a significant instantaneous impact on the global molecular gas content and excitation and we suggest that it only occurs on more localized scales.

Frozen, Cold, or Cool? Chemical Assessment of the Effectiveness of Storage Conditions for Celluloid 3D Objects.

Preserving celluloid artifacts is challenging for museums, as this plastic is highly prone to degradation. Frozen, cold, and cool storage solutions are typically recommended for inhibiting the chemical degradation of celluloid. However, they are rarely implemented for three-dimensional celluloid (3D-CN) objects because low temperatures might cause irreversible effects (e.g., microcracking). This work presents the effects of four different storage temperatures (+23 °C, +13 °C, +9 °C, -15 °C) on the preservation of artificially aged 3D-CN mock-ups, aiming at understanding their effectiveness by measuring molecular weight distribution, camphor, and nitrogen contents after storage. Gel permeation chromatography (GPC) results showed that the least loss of camphor content and fewer polymer chain scissions happened at -15 °C, hinting that this temperature was the best for preservation. However, the heterogeneous nature of celluloid alteration, i.e., the development of degradation gradients in thicker 3D-CN objects (>0.5 mm), made it necessary to apply a novel sampling technique, which selectively considers several depths for analyses from the surface to the core (depth profiling). This depth profiling made monitoring the degradation evolution dependent on the storage conditions in the thicker mock-ups possible. This approach was also used for the first time to quantify the polymer chain scission, camphor loss, and denitration of historical artifacts, indicating a dramatic difference in the degradation stage between surface and core. The effectiveness of frozen storage on the chemical stability of 3D-CN after seven months could support museums to consider reducing the storage temperatures to preserve precious artifacts.

Formation, Evolution, and Antioxidant Activity of Melanoidins in Black Garlic under Different Storage Conditions.

Melanoidins (MLDs) are formed through the reaction of carbonyl compounds and amino compounds in the Maillard reaction (MR) during the heating or storage of food. In this study, the formation, chemical composition, and structural characteristics of black garlic (BG) MLDs stored at different temperatures (4 °C, 20 °C, and 35 °C) over a period of 6 months were investigated. The initial products of the MR formed more often at 4 °C and 20 °C, while higher temperatures (35 °C) promoted the reaction in the middle and late stages of the MR. The higher temperature promoted an increase in molecular weight and MLD content, which can be attributed to the increase in protein and phenolic content. Elemental analysis confirmed an increase in nitrogen (N) content and the continuous incorporation of nitrogen-rich substances into the skeleton. Amino acids, particularly aspartic acid and threonine, were the primary N-containing compounds involved in MLD formation. Additionally, the infrared analysis revealed that the changes in MLDs during storage were characterized by amide I and amide II groups. The MR enhanced the yields of heterocyclic compounds (from 56.60% to 78.89%), especially that of O-heterocyclic compounds, at the higher temperature according to Py-GC-MS analysis. Furthermore, the higher temperature enhanced the molecular weight, maximum height, and roughness of MLDs compared to the control. The antioxidant ability of MLDs was positively correlated with storage temperatures. In summary, temperature had an impact on the formation, evolution, and antioxidant activity of MLDs.

Disk and Envelope Streamers of the GGD 27-MM1 Massive Protostar

We present new Atacama Large Millimeter/submillimeter Array 0.98 mm observations of the continuum emission and several molecular lines toward the high-mass protostellar system GGD 27-MM1, driving the HH 80-81 radio jet. The detailed analysis of the continuum and the CH3CN molecular emission allows us to separate the contributions from the dust content of the disk (extending up to 190 au), the molecular content of the disk (extending from 140–360 au), and the content of the envelope, revealing the presence of several possible accretion streamers (also seen in other molecular tracers, such as CH3OH). We analyze the physical properties of the system, producing temperature and column density maps, and radial profiles for the disk and the envelope. We qualitatively reproduce the trajectories and line-of-sight velocities of the possible streamers using a theoretical model approach. An ad hoc model of a flared disk comprising a hot dust disk embedded in cold gas fits the H2S emission, which revealed the molecular disk as a crescent shape with a prominent central absorption. Another fit to the central absorption spectrum suggests that the absorption is probably caused by different external cold layers from the envelope or the accretion streamers. Finally, the analysis of the rotation pattern of the different molecular transitions in the molecular disk suggests that there is an inner zone devoid of molecular content.

Effects of microwave on the structural and emulsifying properties and interfacial properties of oxidized soybean protein aggregates.

This research explored microwave treatment impact on the structuro-functional aspects of oxidized soy protein aggregates (OSPI). Data showed that oxidative treatment promoted the formation of high molecular weight aggregates through hydrophobic interactions, thereby disrupting the structure of natural soy protein isolates (SPI). Microwave treatment for an appropriate time (≤30s) caused the molecular structure of OSPI to open up and reduction in molecular weight and disulfide bond content, while absolute zeta potential increased. These modifications increased emulsifying capacity of OSPI, as well as the interfacial adsorption of protein. Longer microwave treatment times (>30s) caused OSPI to exhibit a tendency to aggregate in TEM and CLSM images. It indicated the appropriate microwave electromagnetic field effect and microwave heating effect could coordinatively regulate soy protein functional properties by modifying their aggregation behavior. The results provided new ideas for reducing resource waste, and further expanding soy protein application in the food industry.