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The radius of gyration, Rg, and the hydrodynamic radius, Rh, are the main experimental parameters that characterize the size of linear and branched macromolecules. In the case of dendrimers in solution, the ratio Rg/Rh, depending on the global conformation, varies from 1 (for a Gaussian soft sphere) to 3 / 5 (for a hard sphere). However, for high-generation dendrimers, this ratio may be less than the limiting value for a hard sphere. To understand the reasons of the low Rg/Rh value (<0.77), we have studied the second-generation peptide dendrimer containing pH-sensitive histidine amino acid residues (Lys-2His dendrimer) using small-angle x-ray (SAXS) and dynamic light scattering (DLS) experiments, as well as molecular dynamics simulations. The Lys-2His dendrimer takes a swollen conformation at pH = 2 and a collapsed 1 at pH = 7. Our results show that the Rg/Rh ratio for the considered dendrimer decreases from ≈ 3 / 5 at pH = 2 to 0.5 at pH = 7. We have found that the very low Rg/Rh value is due to (1) the formation of a dense impenetrable core (i.e., the transformation of the dendrimer from a Gaussian soft sphere into a sphere with a dense core) and (2) the presence of a larger number of solvent molecules in the dendrimer corona than in a typical macromolecule. In addition, in this work, we have directly confirmed in the experiments for the first time, the collapse of the Lys-2His dendrimer with increasing pH. [ABSTRACT FROM AUTHOR]

Biomolecules inhabit a crowded living cell that is packed with high concentrations of cosolutes and macromolecules that result in restricted, confined volumes for biomolecular dynamics. To understand the impact of crowding on the biomolecular structure, the combined effects of the cosolutes (such as urea) and confinement need to be accounted for. This study involves examining these effects on the collapse equilibria of three model 32-mer polymers, which are simplified models of hydrophobic, charge-neutral, and uncharged hydrophilic polymers, using molecular dynamics simulations. The introduction of confinement promotes the collapse of all three polymers. Interestingly, addition of urea weakens the collapse of the confined hydrophobic polymer, leading to non-additive effects, whereas for the hydrophilic polymers, urea enhances the confinement effects by enhancing polymer collapse (or decreasing the polymer unfolding), thereby exhibiting an additive effect. The unfavorable dehydration energy opposes collapse in the confined hydrophobic and charge-neutral polymers under the influence of urea. However, the collapse is driven mainly by the favorable change in polymer–solvent entropy. The confined hydrophilic polymer, which tends to unfold in bulk water, is seen to have reduced unfolding in the presence of urea due to the stabilizing of the collapsed state by urea via cohesive bridging interactions. Therefore, there is a complex balance of competing factors, such as polymer chemistry and polymer–water and polymer–cosolute interactions, beyond volume exclusion effects, which determine the collapse equilibria under confinement. The results have implications to understand the altering of the free energy landscape of proteins in the confined living cell environment. [ABSTRACT FROM AUTHOR]

We explore theoretically the effects of external potentials on the spatial distribution of particle properties in a liquid of explicitly responsive macromolecules. In particular, we focus on the bistable particle size as a coarse-grained internal degree of freedom (DoF, or "property"), σ, that moves in a bimodal energy landscape, in order to model the response of a state-switching (big-to-small) macromolecular liquid to external stimuli. We employ a mean-field density functional theory (DFT) that provides the full inhomogeneous equilibrium distributions of a one-component model system of responsive colloids (RCs) interacting with a Gaussian pair potential. For systems confined between two parallel hard walls, we observe and rationalize a significant localization of the big particle state close to the walls, with pressures described by an exact RC wall theorem. Application of more complex external potentials, such as linear (gravitational), osmotic, and Hamaker potentials, promotes even stronger particle size segregation, in which macromolecules of different size are localized in different spatial regions. Importantly, we demonstrate how the degree of responsiveness of the particle size and its coupling to the external potential tune the position-dependent size distribution. The DFT predictions are corroborated by Brownian dynamics simulations. Our study highlights the fact that particle responsiveness can be used to localize liquid properties and therefore helps to control the property- and position-dependent function of macromolecules, e.g., in biomedical applications. [ABSTRACT FROM AUTHOR]

Effective "soft" interactions between macromolecules such as polymers, amphiphilic dendrimers, and suitably designed DNA based dendritic molecules have been shown to be purely repulsive and non-diverging. We report the structure and phase behavior of a mixture of hard colloids and soft coarse-grained macromolecules. Through the use of Reference Interaction Site Model theory and molecular dynamics simulations we find that hard colloids and soft macromolecules act as depletants toward each other, generating a medium-induced effective attraction. This effective attraction leads to the formation of non-dispersed phases at high densities. At low and high fractions of hard colloids the system macrophase separates into two disparate regions of hard colloids and soft macromolecules. However, this system microphase separates into a hard-rich and soft-rich self-assembled domains at intermediate compositions. The formation of microphase separated structure in this system of isotropic, disconnected, and purely repulsive colloids is surprising and quite novel. This behavior is likely due to a softening of the interface between hard-rich and soft-rich self-assembled domains. Molecular dynamics simulations have revealed that the microphase separated state has an overall disordered bicontinuous morphology. The hard-rich domain forms an ordered FCC structure and the soft-rich domain forms a disordered cluster-fluid, making the structure simultaneously ordered and disordered. [ABSTRACT FROM AUTHOR]

We show that PEG-induced macromolecular crowding enhances protein detection in nanopores by increasing capture rate and translocation frequency. Experimental data indicate that a PEG concentration gradient boosts capture efficiency, while our theoretical model attributes this enhancement to osmotic flow, offering insights for improving nanopore-based biosensing. [ABSTRACT FROM AUTHOR]

Macromolecules can gain special properties by adopting knotted conformations, but engineering knotted macromolecules is a challenging task. Here, we unexpectedly find that knots can be efficiently generated in active polymer systems. When one end of an actively reptative polymer is anchored, it undergoes continual self-knotting as a result of intermittent giant conformation fluctuations and the outward reptative motion. Once a knot is formed, it migrates to the anchoring point due to a nonequilibrium ratchet effect. Moreover, when the active polymer is grafted on a passive polymer, it can function as a self-propelling soft needle to either transfer its own knots or directly braid knots on the passive polymer. We further show that these active needles can create intermolecular bridging knots between two passive polymers. Our finding highlights the nonequilibrium effects in modifying the dynamic pathways of polymer systems, which have potential applications in macromolecular topology engineering. [ABSTRACT FROM AUTHOR]

AbstractEffective drug delivery to the central nervous system (CNS) remains a challenge due to the blood–brain barrier (BBB). Macromolecules such as proteins and peptides are unable to cross BBB and have poor therapeutic efficacy due to little or no drug distribution. A promising alternative is the conjugation of a drug to a shuttle molecule that can reach the CNS via receptor-mediated transcytosis (RMT). Several receptors have been described for RMT, such as low-density lipoprotein receptor-related protein 1 (LRP1). We used phage display technology combined with an in vitro BBB model to identify LRP1 ligands. A single domain antibody (dAb) library was used to enrich for species that selectively bind to immobilised LRP1 ligand. We obtained a novel nanobody, dAb D11, that selectively binds to LRP1 receptor and mediates in vitro internalisation of phage particles in brain endothelial cells, with a dissociation constant Kd of 183.1 ± 85.8 nM. The high permeability of D11 was demonstrated by an in vivo biodistribution assay in mice. We discovered D11, the first LRP1 binding dAb with BBB permeability. Our findings will contribute to the development of RMT-based drugs for the treatment of CNS diseases. [ABSTRACT FROM AUTHOR]

The ribosome, together with its tRNA substrates, links genotype to phenotype by translating the genetic information carried by mRNA into protein. During the past half-century, the structure and mechanisms of action of the ribosome have emerged from mystery and confusion. It is now evident that the ribosome is an ancient RNA-based molecular machine of staggering structural complexity and that it is fundamentally similar in all living organisms. The three central functions of protein synthesis—decoding, catalysis of peptide bond formation, and translocation of mRNA and tRNA—are based on elegant mechanisms that evolved from the properties of RNA, the founding macromolecule of life. Moreover, all three of these functions (and even life itself) seem to proceed in defiance of entropy. Protein synthesis thus appears to exploit both the energy of GTP hydrolysis and peptide bond formation to constrain the directionality and accuracy of events taking place on the ribosome. The ribosome is an ancient molecular machine that coverts the genetic information carried by mRNA into protein, a crucial step in linking genotype to phenotype. This review discusses landmark advances that furthered our understanding of ribosome structure and function, and lays out some of the fundamental questions that are yet to be answered. [ABSTRACT FROM AUTHOR]

The proportions of carbon (C), nitrogen (N), and phosphorus (P) in surface ocean particulate matter deviate greatly from the canonical Redfield Ratio (C:N:P = 106:16:1) in space and time with significant implications for global carbon storage as this matter reaches the deep ocean. Recent work has revealed clear latitudinal patterns in C:N:P, yet the relative importance of ecological, physiological, or biochemical processes in creating these patterns is unclear. We present high-resolution, concurrent measurements of particulate C:N:P, macromolecular composition, environmental conditions, and plankton community composition from a transect spanning a subtropical-subpolar boundary, the North Pacific Transition Zone. We find that the summed contribution of macromolecules to particulate C, N, and P is consistent with, and provides interpretation for, particulate C:N:P patterns. A decline in particulate C:N from the subtropical to subpolar North Pacific largely reflects an increase in the relative contribution of protein compared to carbohydrate and lipid, whereas variation in C:P and N:P correspond to shifts in protein relative to polyphosphate, DNA, and RNA. Possible causes for the corresponding trends in C:N and macromolecular composition include physiological responses and changes in community structure of phytoplankton, which represented approximately 1/3rd of particulate C across the transect. Comparison with culture experiments and an allocation-based model of phytoplankton macromolecular composition suggest that physiological acclimation to changing nutrient supply is the most likely explanation for the latitudinal trend in C:N, offering both a mechanistic interpretation and biochemical basis for large-scale patterns in C:N:P. [ABSTRACT FROM AUTHOR]

Three main mechanisms of separation in Field-Flow Fractionation, the polarization, steric, and focusing, are critically analyzed. The theoretical evaluation of these mechanisms is accompanied by supporting data from several previous and recent experimental findings. The polarization mechanism can be exploited universally for the macromolecules in solution and for small particulate species. The steric mechanism is impracticable for the separations of the macromolecules in solution. The focusing mechanism was successfully applied in high-speed separations of particulate species, including the biological cells. The major factors differentiating three mechanisms and delimiting their practical use are the strength of the effective field force, the flow-rate of the carrier liquid, and the diffusion coefficients of the separated species. Whenever the highest selectivity is preferred, the polarization and focusing Field-Flow Fractionation, performed under optimal experimental conditions, are rivaling other separation methods. The accuracy, the reproducibility and the repeatability of the field-flow fractionation analyses was evaluated by simultaneous measurements carried out in two independent laboratories. [ABSTRACT FROM AUTHOR]

Although as an analytical method with high specificity and high sensitivity, mass spectrometry (MS) has a wide range of applications in many fields, it still needs other technologies as the assist and supplement to enhance the scope and capability of analysis. Coupling with ion mobility (IM) can make an enhancement effect in the field of pharmaceutical analysis as a supplementary method. The two-dimensional mass technology improves the confidence of compounds annotations while increasing peak capacity, with the gradual deepening of theoretical research on IM-MS, it has shown unique advantages in the complex analysis conditions. IM-MS owns great potential for improving the depth, range, dimension of in-depth drug research. In this review, the principle, instruments and methods, applications, advantages and limitations of IM-MS are described. Here, we also elaborate on the prospects in structural evaluation, separation, and identification of complex compounds for the drug discovery and development phase and the great advantages of macromolecules and omics. [ABSTRACT FROM AUTHOR]

DNA is the macromolecule responsible for storing the genetic information of a cell and it has intrinsic properties such as deformability, stability and curvature. DNA Curvature plays an important role in gene transcription and, consequently, in the subsequent production of proteins, a fundamental process of cells. With recent advances in bioinformatics and theoretical biology, it became possible to analyze and understand the involvement of DNA Curvature as a discriminatory characteristic of gene-promoting regions. These regions act as sites where RNAp (ribonucleic acid-polymerase) binds to initiate transcription. This review aims to describe the formation of Curvature, as well as highlight its importance in predicting promoters. Furthermore, this article provides the potential of DNA Curvature as a distinguishing feature for promoter prediction tools, as well as outlining the calculation procedures that have been described by other researchers. This work may support further studies directed towards the enhancement of promoter prediction software. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are bioactive macromolecules that exhibit antibacterial, antiviral, and immunomodulatory functions. They come from a wide range of sources and are found in all forms of life, from bacteria to plants, vertebrates, and invertebrates, and play an important role in controlling the spread of pathogens, promoting wound healing and treating tumors. Consequently, AMPs have emerged as promising alternatives to next-generation antibiotics. With advancements in systems biology and synthetic biology technologies, it has become possible to synthesize AMPs artificially. We can better understand their functional activities for further modification and development by investigating the mechanism of action underlying their antimicrobial properties. This review focuses on the structural aspects of AMPs while highlighting their significance for biological activity. Furthermore, it elucidates the membrane targeting mechanism and intracellular targets of these peptides while summarizing molecular modification approaches aimed at enhancing their antibacterial efficacy. Finally, this article outlines future challenges in the functional development of AMPs along with proposed strategies to overcome them. [ABSTRACT FROM AUTHOR]

Purpose: Quantitative magnetization transfer (qMT) models aim to quantify the contributions of lipids and macromolecules to the MRI signal. Hence, a model system that relates qMT parameters and their molecular sources may improve the interpretation of the qMT parameters. Here we used membrane lipid phantoms as a meaningful tool to study qMT models. By controlling the fraction and type of membrane lipids, we could test the accuracy, reliability, and interpretability of different qMT models. Methods: We formulated liposomes with various lipid types and water‐to‐lipids fractions and measured their signals with spoiled gradient‐echo MT. We fitted three known qMT models and estimated six parameters for every model. We tested the accuracy and reproducibility of the models and compared the dependency among the qMT parameters. We compared the samples' qMT parameters with their water‐to‐lipid fractions and with a simple MTnorm (= MTon/MToff) calculation. Results: We found that the three qMT models fit the membrane lipids signals well. We also found that the estimated qMT parameters are highly interdependent. Interestingly, the estimated qMT parameters are a function of the membrane lipid type and also highly related to the water‐to‐lipid fraction. Finally, we find that most of the lipid sample's information can be captured using the common and easy to estimate MTnorm analysis. Conclusion: qMT parameters are sensitive to both the water‐to‐lipid fraction and to the lipid type. Estimating the water‐to‐lipid fraction can improve the characterization of membrane lipids' contributions to qMT parameters. Similar characterizations can be obtained using the MTnorm analysis. [ABSTRACT FROM AUTHOR]

Science foremost derives from our curiosity about the world. Can we make sense of the phenomena we see around us? Given that understanding, can we predict previously unimagined phenomena? How do things work? Can we use what we discover to invent new technologies? One class of questions that has mesmerized observers, dating at least to early cave paintings of hunters and their prey, surrounds the nature of the phenomenon we refer to as life. Over the centuries, scientists have found a broad array of surprisingly different techniques for observing, measuring, characterizing and explaining the living world. Microscopes provide a dazzling view of a previously unseen reality that tells us how living organisms are made up and how their components are organized and move. The tools of molecular science tell us the sequence and structure of the macromolecules that fill cells. The data explosion that has attended the development of a new generation of high-throughput tools for querying the living world demands that we have some way of accounting for those data that both provide intuition and make dangerous predictions with no after-the-fact parametric wiggle room. In this special issue of Current Biology , leading researchers explore how physical approaches have contributed to various fields of biology. Here, to introduce this special issue, I consider some of the ways in which viewing the living through a physical lens allows us to see things that might otherwise remain hidden. In this Guest editorial for the special issue, Rob Phillips considers some of the ways in which viewing the living through a physical lens allows us to see things that might otherwise remain hidden. [ABSTRACT FROM AUTHOR]

A novel approach was proposed to enhance the microviscosity sensitivity of molecular rotor probes by integrating flexible rotators and expanded molecular frameworks, addressing the crucial challenge of weakening microviscosity sensitivity in dilute solutions of macromolecules. [ABSTRACT FROM AUTHOR]

Chitin, the second most abundant biopolymer after cellulose, is an important resource for biosourced materials. The global demand for chitin is rapidly increasing, however, the majority of industrial chitin is sourced from crustacean shells, which may be less accessible in regions without seafood waste. Therefore, it is crucial to explore alternative chitin sources, such as those derived from beetles and other arthropods. This study investigated chitin extraction from nine species of Curculionidae (true weevils), which are recognized as crop pests. The extraction process and yields were described, and the isolated chitin was characterized by SEM, IR spectroscopy, elemental analysis, XRD, and ash and water content measurements. This work highlights the potential of Curculionidae as an alternative chitin source. [ABSTRACT FROM AUTHOR]

Carbohydrates are the main macromolecule of poultry feed (40-70 %), categorized into digestible and indigestible forms. Poultry uses digestible carbohydrates to supply energy. Still, the indigestible part (water-soluble and nonsoluble) has different roles in anatomy, histology, water loss, bacterial microflora, mucosal health, normal secretions, feed transport time, and digestion rate in the gastrointestinal tract. Cereals (like corn), the carbohydrate source in poultry feed, can contain mycotoxins or water-soluble indigestible fibers; thus, some mycotoxin-free commercial products contain insoluble indigestible carbohydrates. In this study, the effect of micronized Lignocelluloses (Under trade name ARBOCEL®) was evaluated on calcium metabolism, eggshell quality, and performance of commercial Hy-Line W-36 layers. The results showed that the product had a good effect on the evaluated factors, but in some cases, there was not any significant effect that compared to other groups. However, it is better to evaluate the impact of using this product in various concentrations, ages, periods, heat-stress conditions, and digestive tract microflora disturbance, which is beyond the aim of this study and can be subject to subsequent researches. [ABSTRACT FROM AUTHOR]

Protein–polysaccharide–tannin interactions are important in every aspect of red wine production from physical stability to color, astringency, and body. For this model study, bovine serum albumin (BSA) was selected as the protein, while carboxymethyl cellulose (CMC), mannoproteins, and pectin were the model polysaccharides. Each protein–polysaccharide combination was analyzed for zeta (ζ) potential and particle size at neutral pH and within the wine‐like solution. Mixtures were assessed regarding their protective, affinitive, and aggregative behaviors. Based on their individual ζ‐potentials, pectin and mannoprotein were most stable at lower concentrations. At higher concentrations, they reduced the suspension's stability and increased the aggregate sizes. CMC consistently increased the stability of any solution under neutral pH conditions. However, with increasing concentrations, these large aggregates are expected to precipitate. Fruit pectin (FP) and BSA interactions seemed to be the main factors in the formation of visible precipitates at neutral pH. FP and the mannoprotein decreased stability enough to cause precipitation without haze formation. The mannoprotein decreased particle sizes, in both the suspension and precipitation, which may indicate greater selectivity toward proteins. FP also decreased the suspended particle sizes under wine conditions. These findings demonstrate the use of ζ‐potential and particle size values to characterize macromolecular interactions in model systems and can also be used to indicate effective fining agents. Practical Application: This work demonstrates the capabilities of ζ‐potential analysis paired with size particle measurements to predict and characterize the interactions between macromolecules in complex systems. The interactions between model wine macromolecules can be evaluated with this technology at a level that cannot be reached with any other analytical technique. [ABSTRACT FROM AUTHOR]

Chickpea is an important food legume that usually undergoes various processing treatments to enhance nutritional value and functional properties. This study aimed to investigate the effects of different cooking conditions on physicochemical, structural, and functional properties of chickpea, especially its protein macromolecules. Kabuli chickpea seeds were processed by water cooking at different temperatures (63, 79, 88, and 96°C), followed by evaluating flour solubility, water‐holding capacity (WHC), pasting property, as well as the total protein profile and fractionated protein distributions. Cooking treatments significantly decreased flour solubility (from 39.45 to 25.21 g/100 g flour) and pasting viscosity (peak and final viscosities, from 1081 to 300.5 cP and 1323 to 532 cP, respectively), while increasing WHC (from 0.862 to 1.144 g H2O/g flour) of chickpea flour (p < 0.05). These behaviors were enhanced by increasing cooking temperature. Meanwhile, cooking induced a significant change of chickpea proteins, modifying the albumin‐ and globulin‐like fractions of chickpea protein to display glutelin‐like behavior. The current study provides potential approaches for manipulating chickpea flour functionalities (e.g., solubility, viscosity, and WHC) to address the process and product challenges and favor product innovation. [ABSTRACT FROM AUTHOR]

Conjugated ladder polymers (cLPs) represent an intriguing class of macromolecules, characterized by their multi‐stranded structure, with continuous fused π‐conjugated rings forming the backbone. Isotope substitution, such as deuteration and carbon‐13 labeling, offers unique approaches to address the significant challenges associated with elucidating the structure and solution phase dynamics of these polymers. For instance, selective deuteration can highlight parts of the polymer by controlling the scattering length density of specific molecular sections, thereby enhancing the contrast for neutron scattering experiments. In this context, deuteration of side‐chains in cLPs represents a promising approach to uncover the elusive polymer physics properties of their backbone. The synthesis of two distinct types of cLPs with perdeuterated side‐chains are reported here. During the synthesis, 13C isotope labeling was also employed to verify the low levels of defects in the synthesized polymers. Demonstrating these synthetic successes lays the foundation for rigorous characterization of the defects, conformation, and dynamics of cLPs. [ABSTRACT FROM AUTHOR]

Purpose: The J‐difference edited γ‐aminobutyric acid (GABA) signal is contaminated by other co‐edited signals—the largest of which originates from co‐edited macromolecules (MMs)—and is consequently often reported as "GABA+." MM signals are broader and less well‐characterized than the metabolites, and are commonly approximated using a Gaussian model parameterization. Experimentally measured MM signals are a consensus‐recommended alternative to parameterized modeling; however, they are relatively under‐studied in the context of edited MRS. Methods: To address this limitation in the literature, we have acquired GABA‐edited MEGA‐PRESS data with pre‐inversion to null metabolite signals in 13 healthy controls. An experimental MM basis function was derived from the mean across subjects. We further derived a new parameterization of the MM signals from the experimental data, using multiple Gaussians to accurately represent their observed asymmetry. The previous single‐Gaussian parameterization, mean experimental MM spectrum and new multi‐Gaussian parameterization were compared in a three‐way analysis of a public MEGA‐PRESS dataset of 61 healthy participants. Results: Both the experimental MMs and the multi‐Gaussian parameterization exhibited reduced fit residuals compared to the single‐Gaussian approach (p = 0.034 and p = 0.031, respectively), suggesting they better represent the underlying data than the single‐Gaussian parameterization. Furthermore, both experimentally derived models estimated larger MM fractional contribution to the GABA+ signal for the experimental MMs (58%) and multi‐Gaussian parameterization (58%), compared to the single‐Gaussian approach (50%). Conclusions: Our results indicate that single‐Gaussian parameterization of edited MM signals is insufficient and that both experimentally derived GABA+ spectra and their parameterized replicas improve the modeling of GABA+ spectra. [ABSTRACT FROM AUTHOR]

Purpose: Magnetization transfer saturation (MTsat) mapping is commonly used to examine the macromolecular content of brain tissue. This study compared variable flip angle (VFA) T1 mapping against compressed‐sensing MP2RAGE (csMP2RAGE) T1 mapping for accelerating MTsat imaging. Methods: VFA, MP2RAGE, and csMP2RAGE were compared against inversion‐recovery T1 in an aqueous phantom at 3 T. The same 1‐mm VFA, MP2RAGE, and csMP2RAGE protocols were acquired in 4 healthy subjects to compare T1 and MTsat. Bloch‐McConnell simulations were used to investigate differences between the phantom and in vivo T1 results. Ten healthy controls were imaged twice with the csMP2RAGE MTsat protocol to quantify repeatability. Results: The MP2RAGE and csMP2RAGE protocols were 13.7% and 32.4% faster than the VFA protocol, respectively. At these scan times, all approaches provided strong repeatability and accurate T1 times (< 5% difference) in the phantom, but T1 accuracy was more impacted by T2 for VFA than for MP2RAGE. In vivo, VFA estimated longer T1 times than MP2RAGE and csMP2RAGE. Simulations suggest that the differences in the T1 measured using VFA, MP2RAGE, and inversion recovery could be explained by the magnetization‐transfer effects. In the test–retest experiment, we found that the csMP2RAGE has a minimum detectable change of 2.3% for T1 mapping and 7.8% for MTsat imaging. Conclusions: We demonstrated that MP2RAGE can be used in place of VFA T1 mapping in an MTsat protocol. Furthermore, a shorter scan time and high repeatability can be achieved using the csMP2RAGE sequence. [ABSTRACT FROM AUTHOR]

Multiphase polymeric materials and applications play a prominent role in our society. One of the key challenges is the design and modification of their macromolecules so that the composition and structuring of the phases as well as the interactions between them can be controlled from the molecular scale onwards. In the present contribution, it is highlighted that more recently developed event driven (kinetic) Monte Carlo models provide an interesting framework to grasp molecular variations over various length scales. The strength lies in the tracking of individual molecules per phase of interest so that interphase transfer events can be sampled based on the distributed nature of the (macro)molecules present. Hence, the micro‐scale of local concentrations and temperatures can be connected to the meso‐scale defining interphase transport and morphological variations, with an additional connection to the macro‐ or application scale within reach by adding macro‐scale transfer events to the overall sampling scheme. Starting from a benchmark coupled matrix based Monte Carlo (CMMC) study on the multiphase formation of engineering composites which explicitly acknowledges the type of (macro)molecules present in each phase, it is showcased that the CMMC framework can support the general field of energy and electronics applications. This is highlighted through (i) a case study devoted to the design of polymer electrolytes for batteries, and (ii) a case study on blend design for the regulated stretching of piezoresistive sensors. [ABSTRACT FROM AUTHOR]

Comb-like polymers have shown potential as advanced materials for a diverse palette of applications due to the tunability of their polymer architecture. To date, however, it still remains a challenge to understand how the conformational properties of these polymers arise from the interplay of their architectural parameters. In this work, extensive simulations were performed using dissipative particle dynamics to investigate the effect of grafting density, backbone length, and sidechain length on the conformations of comb-like polymers immersed in a good solvent. To quantify the effect of these architectural parameters on polymer conformations, we computed the asphericity, radius of gyration, and backbone and sidechain end-to-end distances. Bond–bond correlation functions and effective Kuhn lengths were computed to quantify the topological stiffness induced by sidechain–sidechain interactions. Simulation results reveal that the effective Kuhn length increases as grafting density and sidechain length increase, in agreement with previous experimental and theoretical studies. This increase in stiffness results in comb-like polymers adopting extended conformations as grafting density and sidechain length increase. Simulation results regarding the radius of gyration of comb-like polymers as a function of grafting density are compared with scaling theory predictions based on a free energy proposed by Morozova and Lodge [ACS Macro Lett. 6, 1274–1279 (2017)] and scaling arguments by Tang et al. [Macromolecules 55, 8668–8675 (2022)]. [ABSTRACT FROM AUTHOR]

We introduce a Monte-Carlo method that allows for the simulation of a polymeric phase containing a weak polyelectrolyte, which is coupled to a reservoir at a fixed pH, salt concentration, and total concentration of a weak polyprotic acid. The method generalizes the established grand-reaction method by Landsgesell et al. [Macromolecules 53, 3007–3020 (2020)] and, thus, allows for the simulation of polyelectrolyte systems coupled to reservoirs with a more complex chemical composition. In order to set the required input parameters that correspond to a desired reservoir composition, we propose a generalization of the recently published chemical potential tuning algorithm of Miles et al. [Phys. Rev. E 105, 045311 (2022)]. To test the proposed tuning procedure, we perform extensive numerical tests for both ideal and interacting systems. Finally, as a showcase, we apply the method to a simple test system that consists of a weak polybase solution that is coupled to a reservoir containing a small diprotic acid. The complex interplay of the ionization of various species, the electrostatic interactions, and the partitioning of small ions leads to a non-monotonous, stepwise swelling behavior of the weak polybase chains. [ABSTRACT FROM AUTHOR]

[Display omitted] Realizing biomimicry for human tactile perception is a meaningful challenge. In this work, a soft matter system with multi-scale energy dissipation structure is designed to realize flexible sensing and detection by biomimetic human touch. At the molecular scale, the supramolecular interactions are introduced into the hydrogel system, including the hydrophobic interaction and the ion attraction between macromolecular segments. At the micron scale, a system of "button" permeable macromolecules is constructed to absorb external forces and store energy through the sliding of macromolecules inside the "button". By adjusting the molecular scale and micron scale structure, the obtained hydrogels demonstrate excellent mechanical properties, electrical conductivity and response sensitivity. This novel hydrogel withstands 200 compression cycles without creep deformation and outputs a stable response signal in terms of compression cycles with the signal volatility of around 1 %. Based on its good durability, this hydrogel, which simulates human multi-scale tactility, has outstanding application potential in detecting fruit damage that is difficult to observe. Notably, the construction of this multi-scale energy dissipation structure is universal for increasing the mechanical property of ACG hydrogels. The high-strength hydrogels adjusted by this strategy is significantly toughened, and the mechanical properties increased by 38 %. This work is of guiding significance for the preparation of high-performance hydrogels. [ABSTRACT FROM AUTHOR]

In this Review, we reviewed the efforts to expand the applications of conceptual density functional theory reactivity descriptors and hard and soft acid and base principles for macromolecules and other strategies that focused on low-level quantum chemistry methods. Currently, recent applications are taking advantage of modifications of these descriptors using semiempirical electronic structures to explain enzymatic catalysis reactions, protein-binding processes, and structural analysis in proteins. We have explored these new solutions along with their implementations in the software PRIMoRDiA, discussing their impact on the field and its perspectives. We show the main issues in the analysis of the electronic structure of macromolecules, which are the application of the same calculation protocols used for small molecules without considering particularities in those large systems' electronic configuration. The major result of our discussions is that the use of semiempirical methods is crucial to obtain such a type of analysis, which can provide a powerful dimension of information and be part of future low-cost predictive tools. We expect semiempirical methods continue playing an important role in the quantum chemistry evaluation of large molecules. As computational resources advance, semiempirical methods might lead us to explore the electronic structure of even larger biological macromolecular entities and sets of structures representing larger timescales. [ABSTRACT FROM AUTHOR]

Supramolecular polymers (SPs) are constructed through non‐covalent interactions. The dynamic or reversible nature of SPs endows them unique physical and chemical properties, such as self‐adaptive and stimuli‐response abilities. The topological structures of SPs play an important role in determining the physicochemical properties and functionality. Hyperbranched polymers (HBPs) are highly branched 3D macromolecules with linear, dendritic, and terminal units, which makes them versatile candidates for the construction of SPs with fascinating architectures. The resultant HBP‐based SPs perfectly integrated the dynamic/reversible nature of SPs and the 3D topological features and multifunctionality of HBP polymers. To date, various types of HBP‐based SPs and their assemblies have been constructed, and their potential applications have been explored as well. This article overviews the current progress on self‐assembly of HBP‐based SPs. The strategies for construction of HBP‐based SPs and their assemblies are discussed. Typical potential applications of the assemblies of HBP‐based SPs are also introduced. [ABSTRACT FROM AUTHOR]

Click reactions, which are characterized by rapid, high-yielding, and highly selective coupling of two reaction partners, are powerful tools in synthesis but are rarely reversible. Innovative strategies that reverse such couplings in a precise and on-demand manner, enabling a click-clip sequence, would greatly expand the technique's versatility. Herein, a click and clip reaction pair is demonstrated by manipulation of a sulfilimine linkage. Phenothiazines and amines are rapidly and quantitatively coupled through oxidative sulfilimine bond formation with N-bromosuccinimide, and the resulting sulfilimine bromides then undergo quantitative reversion to the phenothiazines and amines through photoreduction at 380 nanometers. This protocol enables fabrication of depolymerizable macromolecules and reversible modification of aminosaccharides, demonstrating high selectivity and efficiency for manipulating sulfilimine linkages in complex systems. [ABSTRACT FROM AUTHOR]

Clustered regularly interspaced short palindromic repeats (CRISPR)-based editing tools have transformed the landscape of genome editing. However, the absence of a robust and safe CRISPR delivery method continues to limit its potential for therapeutic applications. Despite the emergence of various methodologies aimed at addressing this challenge, issues regarding efficiency and editing operations persist. We introduce a microfluidic gene delivery system, called droplet cell pincher (DCP), designed for highly efficient and safe genome editing. This approach combines droplet microfluidics with cell mechanoporation, enabling encapsulation and controlled passage of cells and CRISPR systems through a microscale constriction. Discontinuities created in cell and nuclear membranes upon passage facilitate the rapid CRISPR-system internalization into the nucleus. We demonstrate the successful delivery of various macromolecules, including mRNAs (~98%) and plasmid DNAs (~91%), using this platform, underscoring the versatility of the DCP and leveraging it to achieve successful genome engineering through CRISPR–Cas9 delivery. Our platform outperforms electroporation, the current state-of-the-art method, in three key areas: single knockouts (~6.5-fold), double knockouts (~3.8-fold), and knock-ins (~3.8-fold). These results highlight the potential of our platform as a next-generation tool for CRISPR engineering, with implications for clinical and biological cell-based research. Current approaches for the delivery of CRISPR systems into cells can be hampered by several limitations, including low delivery potential and inefficient genome editing. Here, the authors present Droplet Cell Pincher (DCP), a gene delivery system that combines droplet microfluidics with cell mechanoporation, which attains efficient genome engineering. [ABSTRACT FROM AUTHOR]

This review article explores the recent innovations in the field of antimicrobial and antiviral macromolecules. With the rising challenge of antibiotic resistance, as well as the overuse of antibiotics, there is a growing demand for efficient solutions to combat microbial and viral infections. The development of new effective antimicrobial and antiviral agents is highlighted. This review is designed to give a comprehensive view of the literature focusing on a few examples of combating microbial and viral infections in each section. A brief description of naturally occurring organic‐based materials that exhibit antimicrobial and/or antiviral activities is presented, focusing on polysaccharides, peptides, and proteins. Synthetic organic‐based materials are divided into subsections including polymers, dendrimers, and nanomaterials. The synthesis and applications of inorganic materials such as polyphosphazenes and polysiloxanes, as well as tin‐, germanium‐ and gallium‐based materials are emphasized in this review. Organometallic macromolecules are also described, and their antimicrobial and antiviral activities are examined. Overall, this article provides a comprehensive overview of recent advancements in the design of antimicrobial and antiviral macromolecules, offering valuable insights into their potential applications in biomedical research and combating drug‐resistant microorganisms and viruses. [ABSTRACT FROM AUTHOR]

Circular dichroism (CD) spectroscopy is an analytical technique that measures the wavelength-dependent differential absorbance of circularly polarized light and is applicable to most biologically important macromolecules, such as proteins, nucleic acids, and carbohydrates. It serves to characterize the secondary structure composition of proteins, including intrinsically disordered proteins, by analyzing their recorded spectra. Several computational tools have been developed to interpret protein CD spectra. These methods have been calibrated and tested mostly on globular proteins with well-defined structures, mainly due to the lack of reliable reference structures for disordered proteins. It is therefore still largely unclear how accurately these computational methods can determine the secondary structure composition of disordered proteins. Here, we provide such a required reference data set consisting of model structural ensembles and matching CD spectra for eight intrinsically disordered proteins. Using this set of data, we have assessed the accuracy of several published CD prediction and secondary structure estimation tools, including our own CD analysis package, SESCA. Our results show that for most of the tested methods, their accuracy for disordered proteins is generally lower than for globular proteins. In contrast, SESCA, which was developed using globular reference proteins, but was designed to be applicable to disordered proteins as well, performs similarly well for both classes of proteins. The new reference data set for disordered proteins should allow for further improvement of all published methods. [ABSTRACT FROM AUTHOR]

The hairpin structure is a common and fundamental secondary structure in macromolecules. In this work, the process of the translocation of a model polymer chain with a hairpin structure is studied using Langevin dynamics simulations. The simulation results show that the dynamics of hairpin polymer translocation through a nanopore are influenced by the hairpin structure. Hairpin polymers can be classified into three categories, namely, linear-like, unsteady hairpin, and steady hairpin, according to the interaction with the stem structure. The translocation behavior of linear-like polymers is similar to that of a linear polymer chain. The time taken for the translocation of unsteady hairpin polymers is longer than that for a linear chain because it takes a long time to unfold the hairpin structure, and this time increases with stem interaction and decreases with the driving force. The translocation of steady hairpin polymers is distinct, especially under a weak driving force; the difficulty of unfolding the hairpin structure leads to a low translocation probability and a short translocation time. The translocation behavior of hairpin polymers can be explained by the theory of the free-energy landscape. [ABSTRACT FROM AUTHOR]

Antibodies blocking programmed death-1 (PD-1) and its natural ligand programmed death-ligand 1 (PD-L1) have been proved to be promising strategies in recent years. Hundreds of PD-1/PD-L1 antibodies are under development worldwide. Prediction of human pharmacokinetics (PK) in the preclinical stage is critical for designing dosing regimens in first-in-human studies. This study aims to predict the PK of PD-1/PD-L1 antibodies in human by scaling of monkey data. A systematic literature search of published articles on the PK of PD-1/PD-L1 antibodies in cynomolgus monkey and in human was conducted. Allometric scaling (AS), the species time-invariant (STIV) method, as well as physiologically based pharmacokinetic (PBPK) modeling were investigated. Six antibodies (avelumab, atezolizumab, nivolumab, pembrolizumab, cemiplimab, and zimberelimab) were included for investigation. The exponents used in this study were 0.85 and 1 for clearance (CL) and distribution volume (V), respectively, both for AS and STIV methods. The generic PBPK model for macromolecules in PK-Sim was used without further modifications. The dissociation constant of the antibody for binding to FcRn (K D) in endosome space for human was assumed to be two-fold of that for monkey. Predicted human CLs for the majority of drugs were within the observed range, while Vs were not well predicted using the AS method. The STIV method and the generic PBPK model can be employed to translate concentration-time curves of PD-1/PD-L1 antibodies from cynomolgus monkey to human with comparable efficacy. The results of this study provide reference for the early development of PD-1/PD-L1 antibodies. [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme (GBM) remains one of the most aggressive and treatment-resistant forms of brain cancer, with a notoriously poor prognosis. A major hurdle in effectively targeting GBM is the presence of the blood-brain barrier (BBB), a highly selective barrier that impedes the delivery of therapeutic agents to the tumor site. This review examines the potential of permeable macromolecules as a novel approach for targeted therapy in GBM treatment. We explore the design and function of these macromolecules, which are engineered to traverse the BBB and deliver therapeutic agents directly to the tumor, thereby enhancing treatment efficacy and minimizing systemic toxicity. The review highlights various types of permeable macromolecules, including their mechanisms of BBB penetration, and the strategies employed to optimize their therapeutic payload. We also address the challenges in the development and clinical translation of these macromolecules, including issues related to biocompatibility, pharmacokinetics, and targeted delivery. Additionally, we discuss the potential of these macromolecules in overcoming drug resistance and preventing tumor recurrence, key concerns in GBM treatment. This review underscores the promising future of permeable macromolecules in GBM therapy, offering insights into their role in advancing personalized and targeted treatment strategies. With continued research and development, these macromolecules hold the potential to significantly improve outcomes for patients suffering from this devastating disease. [ABSTRACT FROM AUTHOR]

Autophagy is a finely orchestrated process required for the lysosomal degradation of cytosolic components. The final degradation step is essential for clearing autophagic cargo and recycling macromolecules. Using a CRISPR/Cas9-based screen, we identify RNAseK, a highly conserved transmembrane protein, as a regulator of autophagosome degradation. Analyses of RNAseK knockout cells reveal that, while autophagosome maturation is intact, cargo degradation is severely disrupted. Importantly, lysosomal protease activity and acidification remain intact in the absence of RNAseK suggesting a specificity to autolysosome degradation. Analyses of lysosome fractions show reduced levels of a subset of hydrolases in the absence of RNAseK. Of these, the knockdown of PLD3 leads to a defect in autophagosome clearance. Furthermore, the lysosomal fraction of RNAseK-depleted cells exhibits an accumulation of the ESCRT-III complex component, VPS4a, which is required for the lysosomal targeting of PLD3. Altogether, here we identify a lysosomal hydrolase delivery pathway required for efficient autolysosome degradation. The degradation of inner autophagosomal membranes remains poorly understood. Here, Makar et al. show that RNAseK is involved in a lysosomal hydrolase delivery pathway that contributes to autophagosomal membrane degradation. [ABSTRACT FROM AUTHOR]

Relaxation correction is an integral step in quantifying brain metabolite concentrations measured by in vivo magnetic resonance spectroscopy (MRS). While most quantification routines assume constant T1 relaxation across age, it is possible that aging alters T1 relaxation rates, as is seen for T2 relaxation. Here, we investigate the age dependence of metabolite T1 relaxation times at 3 T in both gray‐ and white‐matter‐rich voxels using publicly available metabolite and metabolite‐nulled (single inversion recovery TI = 600 ms) spectra acquired at 3 T using Point RESolved Spectroscopy (PRESS) localization. Data were acquired from voxels in the posterior cingulate cortex (PCC) and centrum semiovale (CSO) in 102 healthy volunteers across 5 decades of life (aged 20–69 years). All spectra were analyzed in Osprey v.2.4.0. To estimate T1 relaxation times for total N‐acetyl aspartate at 2.0 ppm (tNAA2.0) and total creatine at 3.0 ppm (tCr3.0), the ratio of modeled metabolite residual amplitudes in the metabolite‐nulled spectrum to the full metabolite signal was calculated using the single‐inversion‐recovery signal equation. Correlations between T1 and subject age were evaluated. Spearman correlations revealed that estimated T1 relaxation times of tNAA2.0 (rs = −0.27; p < 0.006) and tCr3.0 (rs = −0.40; p < 0.001) decreased significantly with age in white‐matter‐rich CSO, and less steeply for tNAA2.0 (rs = −0.228; p = 0.005) and (not significantly for) tCr3.0 (rs = −0.13; p = 0.196) in graymatter‐rich PCC. The analysis harnessed a large publicly available cross‐sectional dataset to test an important hypothesis, that metabolite T1 relaxation times change with age. This preliminary study stresses the importance of further work to measure age‐normed metabolite T1 relaxation times for accurate quantification of metabolite levels in studies of aging. [ABSTRACT FROM AUTHOR]

Ganoderma lucidum (GL) is a kind of edible fungus with various functions and a precious medicinal material with a long history. Ganoderma lucidum polysaccharide (GLP) is one of the main bioactive substances in GL, with anti-tumor, anti-oxidation, anti-cancer, and other biological activities. GLP is closely related to human health, and the research on GLP is getting deeper. This paper reviewed the extraction and purification methods of GLP, the relationship between structure and activity, and the qualitative and quantitative methods. This review provides solutions for the analysis and application of GLP. At the same time, some new methods for extraction, purification and analysis of GLP, the relationship between advanced structures and activity, and future applications of and research into GLP were emphasized. As a kind of bioactive macromolecule, GLP has unique functional properties. Through the comprehensive summary of the extraction, purification, and analysis of GLP and its future prospects, we hope that this review can provide valuable reference for the further study of GLP. [ABSTRACT FROM AUTHOR]

Nanowell-based impedance-based label-free biosensors have demonstrated significant advantages in sensitivity, simplicity, and accuracy for detecting cancer biomarkers and macromolecules compared to conventional impedance-based biosensors. Although nanowell arrays have previously been employed for biomarker detection, a notable limitation exists in the photolithography step of their fabrication process, leading to a reduced efficiency rate. Historically, the diameter of these nanowells has been 2 μm. To address this issue, we propose alternative geometries for nanowells that feature larger surface areas while maintaining a similar circumference, thereby enhancing the fabrication efficiency of the biosensors. We investigated three geometries: tube, spiral, and quatrefoil. Impedance measurements of the samples were conducted at 10 min intervals using a lock-in amplifier. The study utilized interleukin-6 (IL-6) antibodies and antigens/proteins at a concentration of 100 nM as the target macromolecules. The results indicated that tube-shaped nanowells exhibited the highest sensitivity for detecting IL-6 protein, with an impedance change of 9.55%. In contrast, the spiral, quatrefoil, and circle geometries showed impedance changes of 0.91%, 0.95%, and 1.62%, respectively. Therefore, the tube-shaped nanowell structure presents a promising alternative to conventional nanowell arrays for future studies, potentially enhancing the efficiency and sensitivity of biosensor fabrication. [ABSTRACT FROM AUTHOR]

To expand the diverse applications of wine lees and enhance the adhesive properties of its protein‐based adhesive, the supernatant of wine lees, separated using the alkali solubilization method, was combined with a small quantity of soybean protein as the raw material. Cross‐linking modification was then conducted using polyacrylamide polymers to prepare the protein‐based adhesive. The results indicated that a total mass fraction of 2.5 wt% NaOH and 3.0 wt% urea effectively stretched the protein structure. Additionally, a mass ratio of 4:10 of trimethylolpropane triglycidyl ether and acrylamide, under the action of the ammonium persulfate initiator, resulted in effective cross‐linking of polyacrylamide macromolecules. The addition of 7 wt% polyacrylamide macromolecules as a cross‐linking agent effectively facilitated the cross‐linking reaction with wine lees‐soy protein. After the cross‐linking modification, the surface of the adhesive became tight and smooth. As a result, the water‐resistance strength of the plywood increased from 0.2 to 1.27 MPa, marking a 635% enhancement, which significantly surpassed the standard for Class II plywood (GB/T 9846‐2015). [ABSTRACT FROM AUTHOR]

The packing geometry of macromolecules in complex mesophases is of key importance to self‐organization in synthetic and biological soft materials. While approximate or heuristic models rely on often‐untested assumptions about how flexible molecules "fit in" to distinct locations of complex assemblies, physical assemblies derive from ensembles of fluctuating conformations, obscuring the connection between mesophase geometry and the underlying arrangements. Here, we present an approach to extract and analyze features of molecular packing in diblock block copolymer (BCP) melts, a prototypical soft matter system, based on the statistical description of chain conformations in self‐consistent field (SCF) theory. We show how average BCP chain trajectories in ordered morphologies can be analyzed from the SCF‐derived orientational order parameter of chain segments. We use these extracted trajectories to analyze the features of local packing geometry, including chain bending and tilt, as well as the terminal boundaries that delineate distinct domains in ordered BCP morphologies. We illustrate this analysis by focusing on measurable features of packing frustration in 2D (columnar) and 3D (spherical and bicontinuous) morphologies, notably establishing an explicit link between chain conformations in complex morphologies and their medial geometry. [ABSTRACT FROM AUTHOR]

Although the majority of RNAs are retained in the nucleus, their significance is often overlooked. However, it is now becoming clear that nuclear RNA forms a dynamic structure through interacting with various proteins that can influence the three-dimensional structure of chromatin. We review the emerging evidence for a nuclear RNA mesh or gel, high-lighting the interplay between DNA, RNA and RNA-binding proteins (RBPs), and assessing the critical role of protein and RNA in governing chromatin architecture. We also discuss a proposed role for the formation and regulation of the nuclear gel in transcriptional control. We suggest that it may concentrate the transcriptional machinery either by direct binding or inducing RBPs to form microphase condensates, nanometre sized membraneless structures with distinct properties to the surrounding medium and an enrichment of particular macromolecules. [ABSTRACT FROM AUTHOR]

With the emergence of ultrafast X‐ray sources, interest in following fast processes in small molecules and macromolecules has increased. Most of the current research into ultrafast structural dynamics of macromolecules uses X‐ray free‐electron lasers. In parallel, small‐scale laboratory‐based laser‐driven ultrafast X‐ray sources are emerging. Continuous development of these sources is underway, and as a result many exciting applications are being reported. However, because of their low flux, such sources are not commonly used to study the structural dynamics of macromolecules. This article examines the feasibility of time‐resolved powder diffraction of macromolecular microcrystals using a laboratory‐scale laser‐driven ultrafast X‐ray source. [ABSTRACT FROM AUTHOR]

Direct methods have practically solved the phase problem for small–medium‐size molecules but have substantially failed in macromolecular crystallography. They have two main limitations: a strong dependence on structural complexity and the need to work with atomic‐resolution data. Many attempts have been made to broaden their field of applicability, for example the use of some a priori information to make the estimate of the triplet invariant phases more effective. Unfortunately none of these new approaches allowed the successful application of direct methods to proteins and nucleic acids. Direct methods are still a niche tool in macromolecular crystallography. In a recent publication [Giacovazzo (2019). Acta Cryst. A75, 142–157] the method of joint probability distributions has been modified to take into account new sources of prior information, one of which is relevant to this article: the Patterson map. In practice, it has been shown that with prior knowledge of the interatomic vectors one is able to modify the classic Cochran reliability parameter for estimating the triplet invariant phases. The article was essentially theoretical in nature, and no attempt was described to test the practical usefulness of the new probabilistic formulas. This work is therefore the first application of the new method. It is shown that the use of the Patterson map as prior information substantially improves the Cochran estimate of triplet phases; the phase error distribution for the new estimates, even if it is related to macromolecular structures, becomes similar to that obtained for medium‐size structures. In some ways, it is as if the use of the Patterson information reduces the structural complexity, thus allowing a more general use of direct methods in macromolecular crystallography. Atomic resolution no longer seems to be a necessary ingredient for the applicability of direct methods; tests show that the apparent reduction in structural complexity also occurs in macromolecular structures with experimental data having a resolution of 2.3 Å. A number of test structures have been used to show the potential of the new technique. [ABSTRACT FROM AUTHOR]

This concept article explores the emerging role of atropisomerism in foldamer chemistry, a field focussed on oligomers that adopt well‐defined conformations through non‐covalent interactions. Atropisomerism introduces a novel dimension to foldamer design by restricting rotational freedom around single bonds to dictate molecular shape with precision. Despite the prevalence of atropisomeric bonds in organic synthesis, their application within foldamers remains underexplored. Here, we discuss key developments in both backbone and sidechain atropisomerism, and suggest future directions for atropisomeric foldamers in the context of a recent surge in atropselective synthetic methods. We propose that judicious use of atropisomerism may serve as a transformative tool in the construction of shape‐defined macromolecules. [ABSTRACT FROM AUTHOR]

In oxygen (O2)‐dependent photodynamic therapy (PDT), photosensitizers absorb light energy, which is then transferred to ambient O2 and subsequently generates cytotoxic singlet oxygen (1O2). Therefore, the availability of O2 and the utilization efficiency of generated 1O2 are two significant factors that influence the effectiveness of PDT. However, tumor microenvironments (TMEs) characterized by hypoxia and limited utilization efficiency of 1O2 resulting from its short half‐life and short diffusion distance significantly restrict the applicability of PDT for hypoxic tumors. To address these challenges, numerous macromolecular nano‐assemblies (MNAs) have been designed to relieve hypoxia, utilize hypoxia or enhance the utilization efficiency of 1O2. Herein, we provide a comprehensive review on recent advancements achieved with MNAs in enhancing the effectiveness of O2‐dependent PDT against hypoxic tumors. [ABSTRACT FROM AUTHOR]

This article delves into an innovative and engaging in-class activity where students harness the power of BuzzFeed-style personality quizzes to unravel the world of biomolecules. Macromolecules, including proteins, nucleic acids, carbohydrates, and lipids, are fundamental components of life, each possessing distinct properties and functions. In this pedagogical approach, students are tasked with associating character traits with macromolecules, creating multiple-choice questions for these character traits, assigning each choice to a macromolecule based on its properties/functions, and summing up results for each macromolecule. A personality quiz is then made and published on the BuzzFeed platform. Students were engaged in this activity and shared the BuzzFeed quiz with their friends and family, which led to classroom content being further discussed outside of class including on social media. Overall, the in-class activity of creating BuzzFeed personality quizzes based on macromolecules is a fun and engaging way for students to learn about the properties and functions of these essential biomolecules. It allows students to explore the material in a creative and interactive way, while also developing important skills in critical thinking and communication. [ABSTRACT FROM AUTHOR]

The primary goal of the study was to develop a green composite material for safe environmental production of human prosthetics using sea urchin (Echinoidea) spike chitin macromolecules, basalt-encapsulated bamboo fiber and epoxy. The chitin biopolymer was extracted from marine waste sea urchin spikes as first time and characterized for its physicochemical properties. The composites' mechanical properties, wear resistance, thermal conductivity, flame retardancy and water absorption were assessed for their suitability in prosthetic applications. The fabrication process adheres to the hand-layup method and follows American society for testing and materials (ASTM) procedure for characterization. Results revealed that the composite EBC3 exhibits improved tensile strength of 165 MPa, flexural strength of 224 MPa, compression strength of 198 MPa, ILSS (interlaminar shear strength) of 31.9 MPa, and impact energy of 5.8 J. Furthermore, composite EBC4 demonstrated superior wear resistance under varying loads and sliding distances. Additionally, EBC4 exhibits a highest thermal conductivity of 0.72 W/mk and a lower flame propagation speed of 5.72 mm/min. Moreover, a low water absorption, indicated by a 101° contact angle in EBC4, guarantees long-term stability of composites. [ABSTRACT FROM AUTHOR]