Small Aggregates Research Articles

A study on the image of Guilin’s urban central space from multidimensional views

In the context of high-quality urban development, strengthening the distinct characteristics of the city itself has become a hot topic. This study focuses on the present Guilin’s urban central space as its research object, aiming to explore the characteristics of Guilin city image through three dimensions: traditional method, spatial syntax, and big data analysis. By exploring the differences presented across these dimensions, the study seeks to analyze the influence of human activities on the spatial form of the city. The investigation reveals that the current development of Guilin’s urban central space manifests a diverse cognitive image characterized by large dispersion, small aggregation, and weak systematicity. The influence of natural landscape on the development of city images in Guilin’s urban central space lies in its ability to facilitate the outlanders’ macroscopic cognition of Guilin’s unique landscape characteristics. However, it also hinders the development of the road network in the urban area, resulting in reduced spatial accessibility and cognitive intensity. In short, Guilin’s urban central space requires systematic integration of the development of multiple images in its future development. This approach entails strengthening the accessibility of public transportation and effectively enhancing the coordination of its unique landscape and natural elements with the development of other urban spaces. Moreover, this study attempts to provide insights into the future planning of cities from the perspective of integrated image development. In addition, it represents a pioneering effort to acquire data and analyze methodologies for cognitive research on city morphology and city image.

Study on evaluation method of circular small shadow profusion in chest CT reconstruction images of pneumoconiosis

Objective: To select chest CT image patterns for the diagnosis of pneumoconiosis and establish a method for determining the profusion of circular small shadows in chest CT. Methods: In April 2021, 66 cases of occupational pneumoconiosis patients with digital radiography (DR) chest radiographs and chest CT imaging data with circular small shadow as the main manifestations were selected as the study objects. 1.5 mm and 5 mm chest CT axial images, 1 mm and 5 mm chest CT coronal multi-plane recombination (MPR) images, and 5 mm chest CT coronal maximum intensity projection (MIP) images were used to observe the different characteristics of pneumoconiosis patients, and were compared and analyzed with DR chest radiographs to establish the experimental chest CT standards. The consistency of the profusion results between the experimental chest CT standards and GBZ 70-2015 Diagnosis of Occupational Pneumoconiosis was verified. Results: All the 66 objects were male, including 33 cases of stage Ⅰ pneumoconiosis, 17 cases of stage Ⅱ pneumoconiosis and 16 cases of stage Ⅲ pneumoconiosis. By observing five chest CT images of 66 objects, we found that chest CT images of different modes could clearly display and identify abnormal images such as small circular shadow, large shadow, small shadow aggregation, honeycomb glass shadow, flake glass shadow, uniform low-profusion glass shadow, mesh glass shadow, cable shadow, linear shadow, subpleural spinous shadow, subpleural nodules, various kinds of emphysema and lung texture distortion and fracture. Small shadow aggregation was usually accompanied by the appearance of large shadow. The vascular shadows in 5 mm CT images had good ductility, and small nodules were easy to distinguish. The coronal MIP image of 5 mm chest CT used edge enhancement technology, which was prone to small shadow fusion and fibrotic shadow fusion. The coronal MPR image of 5 mm chest CT was highly consistent with the DR chest radiographs in terms of the integrity of film reading. GBZ 70-2015 standard was used to compare the profusion of DR chest radiographs and 5 mm chest CT coronal MPR images of 66 objects, and the consistency test Kappa=0.64. GBZ 70-2015 standard and experimental chest CT standard were used to compare the profusion results of DR chest radiographs and 5 mm chest CT coronal MPR images of 66 objects, respectively, and the consistency test Kappa=0.80, with high consistency. Conclusion: 5 mm coronal MPR image is suitable for chest CT imaging in the diagnosis of pneumoconiosis. Following the selection path and method of GBZ 70-2015 profusion criterion, the established experimental chest CT standard in determining the profusion of small circular shadows in 5 mm coronal MPR images of chest CT with pneumoconiosis has a high consistency with GBZ 70-2015 standard.

Predicting Rubisco-Linker Condensation from Titration in the Dilute Phase

The condensation of Rubisco holoenzymes and linker proteins into “pyrenoids,” a crucial supercharger of photosynthesis in algae, is qualitatively understood in terms of “sticker-and-spacer” theory. We derive semianalytical partition sums for small Rubisco-linker aggregates, which enable the calculation of both dilute-phase titration curves and dimerization diagrams. By fitting the titration curves to surface plasmon resonance and single-molecule fluorescence microscopy data, we extract the molecular properties needed to predict dimerization diagrams. We use these to estimate typical concentrations for condensation, and successfully compare these to microscopy observations. Published by the American Physical Society 2024

Formation of a transparent soy protein hydrogel: Controlled thermal aggregation of protein using glutaminase

Plant protein-based hydrogels have enormous potential applications, and their great functional properties and sustainability are considered the best alternatives to reduce the environmental burden of animal protein resources. However, heat-induced plant protein-based hydrogels often exhibit a rough and opaque network structure, limiting their application in various scenarios where gel transparency is crucial. In this study, transparent hydrogels were successfully prepared using deamidated soy protein isolate (SPI) modified by protein-glutaminase (PG). Compared with the non-transparent SPI hydrogel, the deamidated SPI hydrogel possessed a soft and intricate chain-like network, exhibiting excellent light transmittance and certain mechanical strength. The results indicated that deamidation treatment unfolded the structure of SPI, shifting the protein conformation from ordered to disordered, and leading to the transformation of large insoluble protein aggregates into small soluble aggregates. In addition, deamidation treatment effectively inhibited the thermal aggregation rate and aggregation counts of SPI. This was attributed to the conversion of glutamine to glutamic acid, which enhanced the electrostatic repulsion between protein molecules. The present work offers a promising approach for preparing highly transparent plant protein-based hydrogels, which are conducive to developing the next generation of plant protein-based functional materials to replace existing petroleum-based materials.

Early gastric cancer with RhoGAP fusion is linked to frequent nodal metastasis and a part of microtubular-mucocellular histology.

Gastric cancer with fusion genes involving the Rho GTPase-activating protein domain (RhoGAP-GC) is mainly included in the genomically stable type of The Cancer Genome Atlas classification. Clinical implications and histological characteristics of RhoGAP-GC in the early phase remain unclear. We analyzed 878 consecutive pT1b GCs for RhoGAP and its partner genes using fluorescence in situ hybridization assay. RhoGAP fusion was detected in 57 (6.5%) GCs. Univariate analysis revealed that female sex, middle-lower third tumor location, advanced macroscopic type, tumor diameter > 2cm, pT1b2, lymphatic invasion, venous invasion, negative EBER-ISH, and RhoGAP fusion were significantly associated with lymph node metastasis (LNM). Multivariate analysis presented RhoGAP fusion, lymphatic invasion, tumor diameter > 2cm, advanced macroscopic type, venous invasion, and middle-lower third tumor location as independent risk factors for LNM. Notably, RhoGAP fusion had the highest odds ratio (3.92) for LNM among analyzed parameters (95% CI 2.12-7.27; p < 0.001). Compared to non-RhoGAP-GCs, RhoGAP-GCs were significantly frequent in younger females and showed the highest incidence of lymphatic invasion (56.2%) and LNM (49.1%) (p < 0.001). Histologically, microtubular architecture with pseudo-trabecular interconnection and small aggregations of tumor cells with a varied amount of cytoplasmic mucin, named "microtubular-mucocellular (MTMC) histology," was found in 93.0% (53 of 57) of RhoGAP-GCs in the intramucosal area. MTMC histology showed high sensitivity and negative predictive value (93.0% and 99.4%, respectively) for RhoGAP fusion, albeit positive predictive value is low (34.9%). RhoGAP-GC is linked to a characteristic MTMC histology and a high incidence of LNM.

Fish novel TRIM protein FTR14 negatively regulates interferon response by targeting TBK1-IRF3

Growing evidence highlights that tripartite motif (TRIM) family members exert crucial functions in host defense upon infection with microbial pathogens. Of note, the roles of a subfamily of fish-specific TRIM (FTR, also named as finTRIM) which have no true orthologues in mammals were largely unexplored. In this study, a novel FTR gene from grouper (EcFTR14) was identified, and its effects on fish virus infection and host interferon response were investigated. EcFTR14 contained RING, B-Box, and PRY-SPRY domains, and shared 54.81% identity to zebrafish FTR14. The transcription levels of EcFTR14 were markedly induced upon fish virus infection. EcFTR14 was mainly localized in the cytoplasm as small spots or bright aggregates. The overexpression of EcFTR14 could markedly enhance the replication of RGNNV or SGIV. Moreover, overexpression of EcFTR14 reduced the mRNA level of IFN-associated immune signaling molecules, suggesting that the antiviral action of EcFTR14 was due to the negative regulation on IFN response. EcFTR14 was found to interact with EcTBK1, EcIRF3 and EcIRF7, but not with EcSTING. Overexpression of EcFTR14 markedly suppressed the transcription levels of IFN-signaling related molecules evoked by EcSTING and EcTBK1. In addition, overexpression of EcFTR14 could degrade EcTBK1, EcIRF3 and EcIRF7 in a dose-dependent manner, that resulted in the suppression of antiviral effects induced by EcIRF3 and EcTBK1. Collectively, our findings illuminated that EcFTR14, a novel member of FTR family, acted as a pro-viral factor through negatively regulating targeting TBK1-IRF3 activated antviral action. The present study will for the first time shed light on the regulatory roles of FTR14 in innate immune response upon fish virus infection.

Localized surface plasmon resonance and atomic force microscopy study of model lipid membranes and their interactions with amyloid and melatonin

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid plaques in the brain. The toxicity of amyloid to neuronal cell surfaces arises from interactions between small intermediate aggregates, namely amyloid oligomers, and the cell membrane. The nature of these interactions changes with age and disease progression. In our previous work, we demonstrated that both membrane composition and nanoscale structure play crucial roles in amyloid toxicity, and that membrane models mimicking healthy neuron were less affected by amyloid than model membranes mimicking AD neuronal membranes. This understanding introduces the possibility of modifying membrane properties with membrane-active molecules, such as melatonin, to protect them from amyloid-induced damage. In this study, we employed atomic force microscopy and localized surface plasmon resonance to investigate the protective effects of melatonin. We utilized synthetic lipid membranes that mimic the neuronal cellular membrane at various stages of AD and explored their interactions with amyloid-β (1–42) in the presence of melatonin. Our findings reveal that the early diseased membrane model is particularly vulnerable to amyloid binding and subsequent damage. However, melatonin exerts its most potent protective effect on this early-stage membrane. These results suggest that melatonin could act at the membrane level to alleviate amyloid toxicity, offering the most protection during the initial stages of AD.

196 Effects of zinc source and level in low ABC-4 diets on nursery pig growth performance and fecal dry matter

Abstract Incorporating pharmacological levels of Zn in nursery pig diets is a well-recognized practice for reducing post-weaning diarrhea, enhancing growth performance, and enhancing gut health. We hypnotized that the use of a specific form of ZnO (small aggregates and agglomerated particles; SAAP), which provides a greater antibacterial property than standard ZnO, could be added at reduced levels without compromising piglet performance. This study aimed to explore the effects of different levels of SAAP Zn source (HiZox, Animine, France) in low ABC-4 diets with low or high CP content. A total of 360 weanling barrows [DNA 200 × 400, initial body weight (BW) = 5.9 ± 0.4 kg] were used in a 38-d experiment. Pigs were randomly assigned to pens (5 pigs/pen) and pens assigned to 1 of 6 treatments with 12 pens/treatment. The experiment consisted of phase 1 from d 0 to 10, phase 2 from d 11 to 24, and phase 3 from d 25 to 38. Treatments consisted in a negative control (NC), which had 150 ppm of Zn (HiZox) throughout the experiment and the remaining treatments were: positive control (PC) containing 3,000 ppm (phase 1) and 2,000 ppm (phase 2) of Zn provided by ZnO; low-HiZox containing 500 ppm (phase 1) and 300 ppm (phase 2) of Zn; low-HiZox-low-CP was similar to low-HiZox but contained less CP (19.3%) than the NC, PC, low and high-HiZox diets (21.3%); high-HiZox containing 800 ppm (phase 1) and 500 ppm (phase 2) of Zn; and high-HiZox-low-CP was similar to high-HiZox but contained 19.3% CP. In phase 3, all pigs were fed a common diet containing 150 ppm of Zn (HiZox) and high CP. For the experimental period (d 0 to 24), average daily gain (ADG; quadratic, P = 0.007) and average daily feed intake (ADFI; quadratic, P = 0.018) increased as HiZox increased (Table). Pigs fed high-HiZox-low-CP had poorer gain to feed ratio (G:F; P &amp;lt; 0.05) than NC, PC, low-HiZox, and high-HiZox. Additionally, in both experimental and overall periods, pigs fed diets with low CP had decreased G:F (P = 0.043) than those fed the same Zn levels but with high CP. Overall, pigs fed high-HiZox-low-CP had decreased G:F than pigs fed high-HiZox only (732 vs. 761 g/kg, respectively; P &amp;lt; 0.05), with other treatments intermediate. For fecal dry matter (DM), pigs fed low CP diets had greater (P = 0.008) DM compared with pigs fed high CP. Thus, the inclusion of HiZox at 800 and 500 ppm in phases 1 and 2, respectively, in a low-ABC-4 diet might be a strategy to reduce the use of pharmacological levels of Zn from ZnO in nursery diets.

Living Growth Kinetics of Polymeric Micelles on a Substrate.

Living growth of micelles on the substrate is an intriguing phenomenon; however, little is known about its growth kinetics, especially from a theoretical viewpoint. Here, we examine the living growth kinetics of polymeric micelles on a hydrophobic substrate immersed in an aqueous solution. The block copolymers first assemble into short cylinder seeds anchored on the substrate. Then, the small aggregates of block copolymers in the solutions fuse onto the active ends of the anchored seeds, leading to micelle growth on the substrate. A theoretical model is proposed to interpret such living growth kinetics. It is revealed that the growth rate coefficient on the substrate is independent of the copolymer concentration and the multistep feedings; however, it is significantly affected by the surface hydrophobicity. Brownian dynamics simulations further support the proposed growth mechanism and the kinetic model. This work enriches living assembly systems and provides guidance for fabricating bioinspired surface nanostructures.

P-limitation regulates the accumulation of soil aggregates organic carbon during the restoration of Pinus tabuliformis forest

Artificial forest restoration is widely recognized as a crucial approach to enhance the potential of soil carbon sequestration. Nevertheless, there is still limited understanding regarding the dynamics of aggregate organic carbon (OC) and the underlying mechanisms driving these dynamics after artificial forest restoration. To address this gap, we studied Pinus tabuliformis forests and adjacent farmland in three recovery periods (13, 24 and 33 years) in the Loess Plateau region. Samples of undisturbed soil from the surface layer were collected and divided into three aggregate sizes: >2 mm (large aggregate), 0.25–2 mm (medium aggregate), and <0.25 mm (small aggregate). The aim was to examine the distribution of OC and changes in enzyme activity within each aggregate size. The findings revealed a significant increase in OC content for all aggregate sizes following the restoration of Pinus tabuliformis forests. After 33 years of recovery, the OC of large aggregates, medium aggregates and micro-aggregates increased by (30.23 ± 9.85)%, (36.71 ± 21.60)% and (37.88 ± 16.07)% respectively compared with that of farmland. Moreover, the restoration of Pinus tabuliformis forests lead to increased activity of hydrolytic enzymes and decreased activity of oxidative enzymes. It is noteworthy that the regulation of carbon in all aggregates is influenced by soil P-limitation. In large aggregates, P-limitation promotes the enhancement of hydrolytic enzyme activity, thereby facilitate OC accumulation. Conversely, in medium and small aggregates, P-limitation inhibits the increase in oxidative enzyme activity, resulting in OC accumulation. The results emphasize the importance of P-limitation in regulating OC accumulation during the restoration of Pinus tabulaeformis forest, in which large aggregates play a leading role.

Mixed Chinese Fir Plantations Alter the C, N, and P Resource Limitations Influencing Microbial Metabolism in Soil Aggregates

Assessing the limitations of microbial metabolic resources is crucial for understanding plantation soil quality and enhancing fertility management. However, the variation of microbial resource limitations at the aggregate level in response to changes in stands remains unclear. This research explores carbon (C), nitrogen (N), and phosphorus (P) limitations affecting microbial metabolism in bulk soils and aggregates in two mixed and one pure Chinese fir stands in subtropical China, analyzing resource limitations concerning soil carbon, nutrients, and microbial indicators. The results revealed that microbes in all aggregates of the pure stands and in the micro aggregates (&lt;0.25 mm) of the three stands were relatively limited by C and P. In contrast, microbial metabolism was more N-limited in macroaggregates (&gt;2 mm) and small aggregates (2–0.25 mm) in the mixed stands. Additionally, in the mixed stands the proportion of soil macroaggregates increased, and that of micro aggregates decreased, resulting in a shift from C and P limitation to N limitation for bulk soil microbial metabolism. Redundancy analysis identified soil aggregate organic carbon and nutrient content as the main factors affecting microbial resource limitation, rather than their stoichiometric ratios. Pathway analysis further confirmed that soil nutrients and their stoichiometric ratios indirectly influenced soil microbe resource limitation by regulating microbial biomass, microbial respiration, and extracellular enzyme activities. Thus, the impact of mixed plantations on soil nutrients and microbial activity at the aggregate level may be crucial for maintaining land fertility and achieving sustainability.

Evaluating wildlife tourism exposure to Florida manatees using citizen science, public interviews, and trail cameras

Abstract Wildlife tourism often focuses on marine mammals, and the growing frequency of human interactions raises concerns about the sustainability of these activities and their impact on aquatic species. Tourists have the opportunity to view the Florida manatee (Trichechus manatus latirostris) in various locations; however, the level of tourist activity in some areas and their effects on manatees are unknown. Preliminary studies are essential to assess whether these areas warrant additional regulatory and mitigation strategies based on tourism impact. Here, we investigated tourism activity on a site often visited by small aggregations of Florida manatees. From 2022 to 2023, interviews, citizen science, and trail cameras were used to assess watercraft activity, tourist knowledge, and the educational practices offered by watercraft rental businesses at Portosueno Park, Florida, USA. Both trail cameras and citizen science revealed that boats were the most common visitors to the park, averaging 23 watercraft visits per week. Interviews indicated that the majority of the public did not observe the posted signs addressing manatee harassment and were unaware of the prohibition against chasing manatees, the most frequently observed form of harassment at the park. The methods used complemented each other to elucidate tourism activity and has the potential to inform outreach efforts and mitigation strategies.

Fabrication of Poly(ethylene furanoate)/Silver and Titanium Dioxide Nanocomposites with Improved Thermal and Antimicrobial Properties.

Poly(ethylene furanoate) (PEF)-based nanocomposites were fabricated with silver (Ag) and titanium dioxide (TiO2) nanoparticles by the in-situ polymerization method. The importance of this research work is to extend the usage of PEF-based nanocomposites with improved material properties. The PEF-Ag and PEF-TiO2 nanocomposites showed a significant improvement in color concentration, as determined by the color colorimeter. Scanning electron microscopy (SEM) photographs revealed the appearance of small aggregates on the surface of nanocomposites. According to crystallinity investigations, neat PEF and nanocomposites exhibit crystalline fraction between 0-6%, whereas annealed samples showed a degree of crystallinity value above 25%. Combining the structural and molecular dynamics observations from broadband dielectric spectroscopy (BDS) measurements found strong interactions between polymer chains and nanoparticles. Contact angle results exhibited a decrease in the wetting angle of nanocomposites compared to neat PEF. Finally, antimicrobial studies have been conducted, reporting a significant rise in inhibition of over 15% for both nanocomposite films against gram-positive and gram-negative bacteria. From the overall results, the synthesized PEF-based nanocomposites with enhanced thermal and antimicrobial properties may be optimized and utilized for the secondary packaging (unintended food-contact) materials.

An atomistic study of sticking, bouncing, and aggregate destruction in collisions of grains with small aggregates

Molecular dynamics simulations are used to study central collisions between spherical grains and between grains and small grain aggregates (up to 5 grains). For a model material (Lennard-Jones), grain–grain collisions are sticking when the relative velocity v is smaller than the so-called bouncing velocity and bouncing for higher velocities. We find a similar behavior for grain–aggregate collisions. The value of the bouncing velocity depends only negligibly on the aggregate size. However, it is by 35% larger than the separation velocity needed to break a contact; this is explained by energy dissipation processes during the collision. The separation velocity follows the predictions of the macroscopic Johnson–Kendall–Roberts theory of contacts. At even higher collision velocities, the aggregate is destroyed, first by the loss of a monomer grain and then by total disruption. In contrast to theoretical considerations, we do not find a proportionality of the collision energy needed for destruction and the number of bonds to be broken. Our study thus sheds novel light on the foundations of granular mechanics, namely the energy needed to separate two grains, the difference between grain–grain and grain–aggregate collisions, and the energy needed for aggregate destruction.

Integrated Straw Return with Less Power Puddling Improves Soil Fertility and Rice Yield in China’s Cold Regions

The rice production system in China is facing challenges, including declining soil fertility and a stagnant rice yield. This study aimed to test whether integrating the return of straw to fields with less power puddling could simultaneously enhance soil fertility and rice yields. Therefore, field experiments were conducted in Heilongjiang Province, a key rice-growing region in China, from 2017 to 2021, using three different planting methods: control group (CK), straw return (SR) and straw return integrated with less power puddling (SR + LP). The results showed that small soil aggregates (particle diameter &lt; 0.25 mm) and soil bulk density were significantly decreased when straw return was integrated with less power puddling. These changes contributed to the preservation of soil structure. Simultaneously, this approach significantly increased soil ammonium nitrogen content from 9.9 to 10.9 mg kg−1, organic matter content from 35.0 to 36.2 g kg−1, available nitrogen content from 140.5 to 147.0 mg kg−1 and available potassium content from 128.6 to 136.8 mg kg−1 at mature stage on average. Consequently, the post-heading stored assimilates accumulation of rice was increased from 6.12 to 6.43 t ha−1, and the nitrogen, phosphorus and potassium accumulation of rice were increased by 7.85 kg ha−1, 1.13 kg ha−1 and 5.68 kg ha−1, respectively. These changes ultimately resulted in a higher 1000 g weight and filled grain rate, providing the foundation for higher yields (an increase from 9.31 t ha−1 to 9.55 t ha−1). Furthermore, this approach also increased the net income for farmers by USD 14 t ha−1. In summary, this study demonstrates that integrating straw return with less power puddling can enhance soil’s nutrient supply and retention capacity. This enhancement may boost the absorption and transportation of nutrients, ultimately establishing the groundwork for higher yields and economic benefits by enhancing the 1000 g weight and filled grain rate. Future research should delve deeper into its applicability across different ecosystems and investigate the yield-increasing mechanisms.

The Significance of Xylem Structure and Its Chemical Components in Certain Olive Tree Genotypes with Tolerance to Xylella fastidiosa Infection.

Olive quick decline syndrome (OQDS) is a devastating plant disease caused by the bacterium Xylella fastidiosa (Xf). Exploratory missions in the Salento area led to the identification of putatively Xf-resistant olive trees (putatively resistant plants, PRPs) which were pauci-symptomatic or asymptomatic infected plants belonging to different genetic clusters in orchards severely affected by OQDS. To investigate the defense strategies employed by these PRPs to contrast Xf infection, the PRPs were analyzed for the anatomy and histology of xylem vessels, patterns of Xf distribution in host tissues (by the fluorescent in situ hybridization technique-FISH) and the presence of secondary metabolites in stems. The xylem vessels of the PRPs have an average diameter significantly lower than that of susceptible plants for each annual tree ring studied. The histochemical staining of xylem vessels highlighted an increase in the lignin in the parenchyma cells of the medullary rays of the wood. The 3D images obtained from FISH-LSM (laser scanning microscope) revealed that, in the PRPs, Xf cells mostly appeared as individual cells or as small aggregates; in addition, these bacterial cells looked to be incorporated in the autofluorescence signal of gels and phenolic compounds regardless of hosts' genotypes. In fact, the metabolomic data from asymptomatic PRP stems showed a significant increase in compounds like salicylic acid, known as a signal molecule which mediates host responses upon pathogen infection, and luteolin, a naturally derived flavonoid compound with antibacterial properties and with well-known anti-biofilm effects. Findings indicate that the xylem vessel geometry together with structural and chemical defenses are among the mechanisms operating to control Xf infection and may represent a common resistance trait among different olive genotypes.

Acid-induced pea protein gels pretreated with media milling: Gelling properties and the formation mechanism

This study explored the effect of stirred media mill (SMM) processing on the acid-induced gelling properties of pea protein. Results showed that SMM treatment enhanced the gel strength from 75.06 g to 183.89 g and increased the water holding capacity from 46.64 % to 73.50 %. The minimum gelation concentration achieved for SMM-treated pea protein was 4 %, significantly lower than that of heat-pretreated pea protein (9 %). SMM decreased protein aggregate size from 104 μm to 180 nm. Microscopy analysis revealed that the small aggregates facilitated the formation of uniform gel networks with tight connections. Linear rheology indicated that small protein aggregates resulted in slower gelation rates with a higher Gʹ for the formed gels. The SMM-pretreated protein gel showed strain hardening, shear thinning behaviors, and satisfactory stability to withstand large-amplitude oscillatory shear. Overall, SMM emerges as a promising technology for producing protein gel products with strong mechanical attributes and customizable rheological properties.

Synthesis and Thermo-Responsive Behavior of Poly(N-isopropylacrylamide)-b-Poly(N-vinylisobutyramide) Diblock Copolymer.

Thermo-responsive diblock copolymer, poly(N-isopropylacrylamide)-block-poly(N-vinylisobutyramide) was synthesized via switchable reversible addition-fragmentation chain transfer (RAFT) polymerization and its thermal transition behavior was studied. Poly(N-vinylisobutyramide) (PNVIBA), a structural isomer of poly(N-isopropylacrylamide) (PNIPAM) shows a thermo-response character but with a higher lower critical solution temperature (LCST) than PNIPAM. The chain extension of the PNVIBA block from the PNIPAM block proceeded in a controlled manner with a switchable chain transfer reagent, methyl 2-[methyl(4-pyridinyl)carbamothioylthio]propionate. In an aqueous solution, the diblock copolymer shows a thermo-responsive behavior but with a single LCST close to the LCST of PNVIBA, indicating that the interaction between the PNIPAM segment and the PNVIBA segment leads to cooperative aggregation during the self-assembly induced phase separation of the diblock copolymer in solution. Above the LCST of the PNIPAM block, the polymer chains begin to collapse, forming small aggregates, but further aggregation stumbled due to the PNVIBA segment of the diblock copolymer. However, as the temperature approached the LCST of the PNVIBA block, larger aggregates composed of clusters of small aggregates formed, resulting in an opaque solution.

Molecular dynamics simulations as a guide for modulating small molecule aggregation

Small colloidally aggregating molecules (SCAMs) can be problematic for biological assays in drug discovery campaigns. However, the self-associating properties of SCAMs have potential applications in drug delivery and analytical biochemistry. Consequently, the ability to predict the aggregation propensity of a small organic molecule is of considerable interest. Chemoinformatics-based filters such as ChemAGG and Aggregator Advisor offer rapid assessment but are limited by the assay quality and structural diversity of their training set data. Complementary to these tools, we explore here the ability of molecular dynamics (MD) simulations as a physics-based method capable of predicting the aggregation propensity of diverse chemical structures. For a set of 32 molecules, using simulations of 100 ns in explicit solvent, we find a success rate of 97% (one molecule misclassified) as opposed to 75% by Aggregator Advisor and 72% by ChemAGG. These short timescale MD simulations are representative of longer microsecond trajectories and yield an informative spectrum of aggregation propensities across the set of solutes, capturing the dynamic behaviour of weakly aggregating compounds. Implicit solvent simulations using the generalized Born model were less successful in predicting aggregation propensity. MD simulations were also performed to explore structure-aggregation relationships for selected molecules, identifying chemical modifications that reversed the predicted behaviour of a given aggregator/non-aggregator compound. While lower throughput than rapid cheminformatics-based SCAM filters, MD-based prediction of aggregation has potential to be deployed on the scale of focused subsets of moderate size, and, depending on the target application, provide guidance on removing or optimizing a compound’s aggregation propensity.Graphical

Fishing damage to cloud sponges may lead to losses in associated fish communities in Pacific Canada

Glass sponge gardens are important biogenic habitats that support fish communities in Pacific Canada. However, glass sponges (class Hexactinellida) are delicate and susceptible to damage from fishing gear such as downriggers. In this study we document changes in a fish community before –and after damage from a presumed fishing event that resulted in a reduction of 58.9% of the available sponge habitat in a small cloud sponge garden in British Columbia. This habitat loss coincided with a decline of 76.9% of the relative abundance of rockfish, an economically important group of fishes, at the garden. This decline was particularly pronounced in small size classes with the disappearance of juvenile rockfish after the sponge loss. Although based on a single site, this is the first documentation of how anthropogenic damage in a sponge aggregation may impact the associated fish community. Damage from fishing gear is likely most pronounced in small sponge aggregations, like nearshore gardens, where a single event may result in a disproportionately large loss of available fish habitat. Slow regrowth of sponges suggests the habitat availability may be permanently altered at these sites and can coincide with shifts in the localized fish community that may be long lasting on a local scale. Currently sponge gardens do not have any direct spatial protections in the Pacific Northwest, and this work highlights the importance of considering them in future protection initiatives.