Formation Of Structure Research Articles

CLSTN3B promotes lipid droplet maturation and lipid storage in mouse adipocytes

Interorganelle contacts facilitate material exchanges and sustain the structural and functional integrity of organelles. Lipid droplets (LDs) of adipocytes are responsible for energy storage and mobilization responding to body needs. LD biogenesis defects compromise the lipid-storing capacity of adipocytes, resulting in ectopic lipid deposition and metabolic disorders, yet how the uniquely large LDs in adipocytes attain structural and functional maturation is incompletely understood. Here we show that the mammalian adipocyte-specific protein CLSTN3B is crucial for adipocyte LD maturation. CLSTN3B employs an arginine-rich segment to promote extensive contact and hemifusion-like structure formation between the endoplasmic reticulum (ER) and LD, allowing ER-to-LD phospholipid diffusion during LD expansion. CLSTN3B ablation results in reduced LD surface phospholipid density, increased turnover of LD-surface proteins, and impaired LD functions. Our results establish the central role of CLSTN3B in the adipocyte-specific LD maturation pathway that enhances lipid storage and maintenance of metabolic health under caloric overload in mice of both sexes.

A “core-shell” structure imparting both gas barrier and UV shielding properties for a PLA/ PGA/ PBS ternary blend film

The core-shell structure enhances polymer blend systems by orderly assembly and leveraging complementary properties. This study aims to enhance the flexibility and barrier properties of polylactic acid (PLA, L) by blending it with polyglycolic acid (PGA, G) for gas barrier and polybutylene succinate (PBS, B) for flexibility. Encapsulating PGA in a core-shell structure using PBS resolves PGA's rapid hydrolysis issue. The theoretical models predicting dispersion patterns based on spreading coefficients and interfacial tensions were validated through SEM observations, confirming the formation of a core-shell structure in the 5L1G4B ternary blend. Compared to the PLA/PBS binary blend film, samples with PGA (5L1G4B and 4L1G5B) exhibit higher elongation at break and tearing strength. For instance, the elongation at break of the 5L1G4B sample increases from 272.3 % of 6L4B to 470.85 %. The 5L1G4B showed comparable oxygen and carbon dioxide barrier properties to the 6L4B sample. The 5L1G4B and 4L1G5B samples show <2 % UV transmittance in the UVA region, indicating excellent UV shielding. The 5L1G4B blend film, with its mechanical properties, oxygen barrier, UV resistance, and biodegradability, is ideal for outer layer packaging film and has the potential to replace LDPE in packaging juice and dairy product bottles.

Fluoride- and OSDA-free synthesis of ZSM-5 with controllable b-axis orientation: Insights into the role of medium alkalinity and seed induction

MFI-topology nanosheets with a b-axis-oriented structure are valuable catalysts in diffusion-controlled acid-catalyzed reactions. Therefore, b-axis-oriented ZSM-5 nanosheets were synthesized herein in a fluoride-free solution without using special additives and complex methods. The initial gel pH of mixed raw materials was adjusted to approximately 5–7 (weak acidity) to direct nanosheet structure formation. The target ZSM-5 zeolite with a b-axis-oriented structure was achieved through the synergistic effect between the involved gel pH and seed solution. The seed solution directed the formation of an MFI structure, and the low alkalinity of the gel limited crystal growth in the b plane, thereby affording b-axis-oriented thin sheets. The ratio of the lengths of the c and b axes of the obtained ZSM-5 could be effectively tuned by adjusting the pH of the initial gel. Compared with the nanosized hexagonal ZSM-5 sample synthesized in a strong-basic system, the as-synthesized b-axis-oriented ZSM-5 exhibited a lower coking rate and higher propylene yield during the considered 1-hexene cracking reaction.

Integrated respiratory toxicity of municipal wastewater to human bronchial epithelial cells and 3D bronchospheres

Respiratory symptoms have been reported in wastewater treatment workers and residents living close to sewage treatment plant. However, toxicological research about the respiratory hazards of municipal wastewater is scarce. The present study aims to gain insight into the comprehensive respiratory hazards induced by the contaminant mixtures in municipal wastewater. The integrated respiratory hazards of effluents from four secondary wastewater treatment plants (SWTPs), a tertiary wastewater treatment plant (TTP), and a constructed wetland (CW) were evaluated using normal human bronchial epithelial cells (NHBE) bioassay, and toxicity reduction efficiency of various treatment techniques was analyzed. Effluents caused cytotoxicity, oxidative damage, inflammation response with the increased levels of IL-6 and CXCL8, and impaired barrier integrity with decreased expressions of ZO-1 and occludin in NHBE. Further, the effluents inhibited the development of 3D bronchospheres, increased irregular surface and cell debris, and suppressed the formation of luminal structures. TTP E effluent significantly increased the expression of MUC5AC in bronchospheres. The integrated biomarker response (IBR) of the influent was removed by 40.2% at SWTPs, 18.2% at TTP, and 36.6% at CW, respectively. The IBR of the final effluents from SWTPs, TTP, and CW were 7.2, 7.7, and 7.7, respectively. Significant correlation with toxicity biomarkers was frequently observed for stearyl alcohol, o-cresol, phenanthrene, butylated hydroxytoluene, and dimethyl phthalate. The present study provided human relevant evidence concerning the adverse respiratory effects associated with discharge. The necessity for deep water treatment, performance optimization, and the potential means were suggested for improving water quality and protecting respiratory health.

Cyclic Oxothiomolybdates: Building Blocks for Cyclodextrin-Based Open Frameworks.

Desolvation processes, though common in self-assembled biological structures, are rarely evidenced and utilized in the design of crystalline architectures. In this study, we introduce a novel approach using the [Mo8S8O8(OH)8(guest)]2- complex, formed by the self-condensation of four [MoV 2O2S2]2- fragments around a guest unit (MoVIO6H4 or oxalate), as a chaotropic scaffold for crystallizing hybrid organic-inorganic systems with natural cyclodextrins. Our findings reveal that β-cyclodextrin (β-CD) facilitates the formation of host-guest complexes, while α-cyclodextrin (α-CD) induces the formation of a Kagome-type structure with significant voids. These new compounds were thoroughly characterized using X-ray diffraction (both powder and single-crystal), N2 adsorption, elemental and thermogravimetric analysis. Additionally, solution studies using 1H NMR titration and small-angle X-ray scattering (SAXS) demonstrated pre-association of the building units in solution. These results enhance our understanding of the design principles for supramolecular structures composed of inorganic polyanions and cyclodextrins.

Performance and mechanism of the structure formation and physical-mechanical properties of concrete by modification with nanodiamonds

Performance and mechanism of the structure formation and physical-mechanical properties of concrete by modification with nanodiamonds

Syntheses of Novel Spirobenzazepinoindole Derivatives via Lewis-Acid Catalyzed Pictet-Spengler Cyclization.

The syntheses of novel spirobenzazepinoindole derivatives has been achieved through a highly efficient and synthetic route. The approach involves a two-step reaction, utilizing indole derivatives, 2-amino benzyl alcohol, and ninhydrin as key starting materials under mild reaction conditions. The reaction proceeds via a sequential cascade process involving cyclization, condensation and spiro-annulation, leading to the formation of the spirobenzazepinoindole core structure in good to excellent yields. The method offers broad substrate scope, high atom economy, and operational simplicity. The synthesized spirobenzazepinoindoles were fully characterized by spectroscopic techniques, including NMR (1H & 13C), IR and mass spectrometry. The methodology provides a valuable tool for the rapid generation of structurally complex spirobenzazepinoindoles, which could serve as scaffolds for the development of new therapeutic agents.

Susceptibility of Leishmania amazonensis Axenic Amastigotes to the Calpain Inhibitor MDL28170

Leishmaniasis encompasses a group of neglected diseases caused by flagellated protozoa belonging to the Leishmania genus, associated with high morbidity and mortality. The search for compounds with anti-Leishmania activity that exhibit lower toxicity and can overcome the emergence of resistant strains remains a significant goal. In this context, the calpain inhibitor MDL28170 has previously demonstrated deleterious effects against promastigote forms of Leishmania amazonensis, which led us to investigate its role on axenic amastigote forms. The calpain inhibitor MDL28170 was able to decrease the viability of amastigotes in a typically dose-dependent manner. The treatment with the IC50 dose (13.5 μM) for 72 h led to significant amastigote lysis and increased cell-to-cell aggregation. Ultrastructural analysis revealed several cellular alterations, including disruption of the trans-Golgi network and the formation of autophagosomes when treated with MDL28170 at ½ × IC50 dose. Additionally, mitochondrial swelling and the formation of concentric membranous structures inside the mitochondrion were observed after incubation with the IC50 dose. These results reinforce the potential application of the calpain inhibitor MDL28170 against L. amazonensis, highlighting its effectiveness and possible mechanism of action against the parasite.

Simple and Cost-Effective Generation of 3D Cell Sheets and Spheroids Using Curvature-Controlled Paraffin Wax Substrates

The challenges associated with animal testing in pharmaceutical development have driven the search for alternative in vitro models that mimic human tissues more accurately. In this study, we present a simple and cost-effective method for generating 3D cell sheets and spheroids using curvature-controlled paraffin wax films, which are easily accessible laboratory materials that eliminate the need for extracellular matrix (ECM) components or thermo-responsive polymers. By adjusting the curvature of the paraffin wax film, we successfully generated human periodontal ligament fibroblast (HPdLF) cell sheets and bone marrow-derived mesenchymal stem cell (hBMSC) spheroids. Key parameters, such as cell density, substrate curvature, and incubation time, were identified as critical factors for optimizing the formation of these 3D structures. In addition, the use of quantum dots (QDs) for cell tracking enabled long-term visualization and distinction between different cell types within complex tissue-like structures. We further demonstrated that wrapping the hBMSC spheroids with HPdLF cell sheets partially replicated the connective tissue structure of the periodontal ligament surrounding the tooth root. This highlights the potential of this platform for the construction of more sophisticated tissue-mimicking assemblies. In conclusion, curvature-controlled paraffin wax films provide a versatile and practical approach for 3D cell cultures. This simplifies the generation of both cell sheets and spheroids, offering a promising tool for tissue engineering and regenerative medicine applications, where precise cell-to-cell interactions are essential.Graphical abstract

Hydrogel network formation triggers atypical hygroscopic behavior in atmospheric aerosols.

The phase state of atmospheric aerosol particles, dictated by composition, intermolecular interaction, size, and pH, profoundly impacts climate, human health, and air quality. Herein, the phase behavior of internally mixed sodium bitartrate (SBT) and ammonium sulfate (AS) aerosols with equal molar ratio was studied using microscopic imaging, confocal Raman and infrared spectroscopy. We observed atypical phase transition during hygrosopic cycles. On dehydration, micro-solids formed at relative humidity (RH) of 80.1 % without further efflorescence, namely limited efflorescence (LE). On hydration, droplets effloresced at 39.8 % RH and deliquesced at 68.8 % RH, referred as efflorescence on hydration (EH). Raman spectra show that Na2SO4 solids form during LE, while both Na2SO4 and (NH4)2SO4 solids form during EH. The phase transition of the SBT/AS (1:1) droplets is size-dependent, where smaller droplets are prone to "EH" while larger droplets are prone to typical efflorescence. Combining AIOMFAC-VISC viscosity predictions with scanning electron microscopy (SEM) images, we attribute the "LE" and "EH" phenomena to the formation of an ion-organic hydrogel network structure within droplets. pH and organic/inorganic mixing ratios can collaboratively affect the stability of hydrogel network by changing the organic/inorganic mixing ratios. Our study shows that gel network formation can cause atypical phase transition in atmospheric aerosols.

Structure Formation Through Magnetohydrodynamical Instabilities in Primordial Disks

The shear flow instabilities under the presence of magnetic fields in the primordial disk can greatly facilitate the formation of density structures that serve as seeds prior to the onset of the gravitational Jeans instability. We evaluate the effects of the Parker, magnetorotational and kinematic dynamo instabilities by comparing the properties of these instabilities. We calculate the mass spectra of coagulated density structures by the above mechanism in the radial direction for an axisymmetric magnetohydrodynamic (MHD) torus equilibrium and power density profile models. Our local three-dimensional MHD simulation indicates that the coupling of the Parker and magnetorotational instability creates spiral arms and gas blobs in an accretion disk, reinforcing the theory and model. Such a mechanism for the early structure formation may be tested in a laboratory. The recent progress in experiments involving shear flows in rotating tokamak, field reversed configuration (FRC) and laser plasmas may become a key element to advance in nonlinear studies.

How Do Primordial Black Holes Change the Halo Mass Function and Structure?

We examine the effects of massive primordial black holes (PBHs) on cosmic structure formation, employing both a semianalytical approach and cosmological simulations. Our simulations incorporate PBHs with a monochromatic mass distribution centered around 106 M ⊙, constituting a fraction of 10−2 to 10−4 of the dark matter (DM) in the Universe, with the remainder being collisionless particle DM. Additionally, we conduct a ΛCDM simulation for comparative analysis with runs that include PBHs. At smaller scales, halos containing PBHs exhibit similar density and velocity dispersion profiles to those without PBHs. Conversely, at larger scales, PBHs can expedite the formation of massive halos and reside at their centers owing to the “seed effect.” To analyze the relative distribution of PBH host halos compared to non-PBH halos, we apply nearest neighbor statistics. Our results suggest that PBH host halos, through gravitational influence, significantly impact the structure formation process, compared to the ΛCDM case, by attracting and engulfing nearby newly formed minihalos. Should PBHs constitute a fraction of DM significantly larger than ∼10−3, almost all newly formed halos will be absorbed by PBH-seeded halos. Consequently, our simulations predict a bimodal feature in the halo mass function, with most of the massive halos containing at least one PBH at their core and the rest being less massive non-PBH halos.

Tailored Regulation of Graphite Microcrystals via Tandem Catalytic Carbonization for Enhanced Electrochemical Performance of Hard Carbon in the Low‐Voltage Plateau

AbstractThe sodium storage behavior in the plateau region is crucial for determining the capacity and rate capability of hard carbon (HC) anodes in sodium‐ion batteries (SIBs). Key structural features for achieving excellent plateau performance include extended graphite domains and increased interlayer spacing. However, synchronously optimizing these two structures is challenging due to their inherent trade‐off. Herein, a tandem catalytic carbonization strategy is developed to construct HC with long graphite domains (La = 5.31 nm) and large interlayer spacing (d002 = 0.389 nm) simultaneously. Comprehensive in situ and ex situ tests unravel the catalytic selective bond breaking and aromatization effects of ZnCl2, the catalytic graphitic layers enlargement and occupied effects of formed ZnO and Zn in different temperature stages, leading to the formation of the unique structure. The optimal HCZ‐0.1 exhibits a high reversible capacity of 346.9 mAh g−1 with a plateau capacity of 249.4 mAh g−1, and high‐rate performance (114.0 mAh g−1 at 5 A g−1). In addition, the sodium storage mechanism and origin of enhanced Na+ kinetics of HCZ‐0.1 are also revealed. This work offers a precise method to engineer the graphite microcrystal structure in HC for superior sodium storage in the plateau region.

Cavity formation in silica‐filled rubber compounds observed during deformation by ultra small‐angle x‐ray scattering

AbstractWhen silica‐filled rubber compounds are deformed, structural modifications in the material's bulk lead to irreversible damage, the most significant of which is cavitation appearing within the interfaces of interconnected polymer and filler networks. This work introduces a new method to analyze cavitation in industrial‐grade rubbers based on ultra small‐angle x‐ray scattering. This method employs a specially designed multi‐sample stretching device for high‐throughput measurements with statistical relevance. The proposed data reduction approach allows for early detection and quantification of cavitation while providing at the same time information on the hierarchical filler structures at length scales ranging from the primary particle size to large silica agglomerates over four orders of magnitude. To validate the method, the scattering of SSBR rubber compounds filled with highly dispersible silica at different ratios was measured under quasi‐static strain. The strain was applied in incremental steps up to a maximum achievable elongation or breakage of the sample. From the measurements performed in multiple repetitions, it was found that the minimum strain necessary for cavity formation and the size evolution of the cavities with increasing strain are comparable between these samples. The sample with the highest polymer content showed the lowest rate of cavity formation and higher durability of silica structures. The structural stability of the compounds was determined by the evolution of the filler hierarchical structures, obtained by fitting data across the available strain range.

Structure, Optical Properties and Magnetocaloric Effects in Gd3Fe5O12 Garnet Synthesized by Solid State Method

In this work, gadolinium iron garnet (Gd3Fe5O12) was synthesized using the solid-state ceramic method. The structural analysis, confirmed through Rietveld refinement, indicated the formation of a single-phase garnet structure. Scanning electron microscopy studies revealed uniform grain size and homogeneity in the sintered material, while UV-vis absorption studies showed a peak at 300 nm, indicating strong ultraviolet interaction and an optical band gap of 3.64 eV, suggesting optoelectronic potential. The fluorescence emission spectrum shows a band at 435 nm, while the excitation spectrum exhibits bands at 275 and 360 nm. The magnetic measurements demonstrated Gd ion ordering at low temperatures, with a compensation temperature around 290 K. Arrott plots confirmed the second-order magnetic phase transition. Importantly, Gd3Fe5O12 exhibited both normal and inverse magnetocaloric effects, with a maximum magnetic entropy change of 1.05 J kg–1 K–1 at 230 K under 9 T magnetic field. These properties indicate Gd3Fe5O12 material as a promising candidate for magnetic refrigeration and optoelectronic applications.

Field‐Free Spin‐Orbit Torque Switching in Perpendicularly Magnetized Ta/CoFeB/MgO/NiO/Ta with a Canted Antiferromagnetic Insulator NiO Interlayer

AbstractIn this study, deterministic current‐induced spin‐orbit torque (SOT) magnetization switching is achieved, particularly in systems with perpendicular magnetic anisotropy (PMA), without the need for a collinear in‐plane field, a traditionally challenging requirement. In a Ta/CoFeB/MgO/NiO/Ta structure, spin reflection at the MgO/NiO interface generates a spin current with an out‐of‐plane spin polarization component σz. Notably, the sample featuring 0.8 nm MgO and 2 nm NiO demonstrates an impressive optimal switching ratio approaching 100% without any in‐plane field. A systematic investigation of the effects of the MgO and NiO thickness demonstrates that the formation of noncollinear spin structures and canted magnetization in the ultrathin NiO interlayer plays a pivotal role to the field‐free SOT switching. The integration of NiO as an antiferromagnetic insulator effectively mitigates current shunting effects and enhances the thermal stability of the device. This advancement in the CoFeB/MgO system holds promise for significant applications in spintronics, marking a crucial step toward realizing innovative technologies.

Cryo-EM structure of the heteromeric TRPC1/TRPC4 channel.

Transient receptor potential (TRP) ion channels have a crucial role as cellular sensors, mediating diverse physical and chemical stimuli. The formation of heteromeric structures expands the functionality of TRP channels; however, their molecular architecture remains largely unknown. Here we present the cryo-electron microscopy structures of the human TRPC1/TRPC4 heteromer in the apo and antagonist-bound states, both consisting of one TRPC1 subunit and three TRPC4 subunits. The heteromer structure reveals a distinct ion-conduction pathway, including an asymmetrically constricted selectivity filter and an asymmetric lower gate, primarily attributed to the incorporation of TRPC1. Through a structure-guided electrophysiological assay, we show that both the selectivity filter and the lower part of the S6 helix participate in deciding overall preference for permeating monovalent cations. Moreover, we reveal that the introduction of one lysine residue of TRPC1 into the tetrameric central cavity is enough to render one of the most important functional consequences of TRPC heteromerization: reduced calcium permeability. Our results establish a framework for addressing the structure-function relationship of the heteromeric TRP channels.

In defense of obscure academic writing

There has been a backlash against academic writing in the humanities that can be found in popular culture at least since the 1990s. By considering a selection of arguments from critics of academic writing in the humanities, I then defend a certain kind of ‘obscurity’ or ‘difficulty’ in scholarly prose by developing a concise genealogy of obscure academic writing. This paper develops the notion that an ‘uncommon sense’ should be situated against ‘common sense’ to unveil an assumed ‘world’ or ‘reality’ alongside the structural formations of that which is considered ‘useful’ language. Often, complicated academic language grapples with the intrinsic complexity that is hidden behind ‘simple’ ideas.

Geometric Frustration Directs the Self-assembly of Nanoparticles with Crystallized Ligand Bundles.

Polymer-grafted nanoparticles are versatile building blocks that self-assemble into a diverse range of mesostructures. Coarse-grained molecular simulations have commonly accompanied experiments by resolving structure formation pathways and predicting phase behavior. Past simulations represented nanoparticles as spheres and the ligands as flexible chains of beads, isotropically tethered to the nanoparticles. Here, we investigate a different minimal coarse-grained model. The model consists of an attractive rod tethered to a repulsive sphere. The motivation of this rod-sphere model is to describe nanospheres with a partially crystallized, stretched polymeric bundle as well as other complex building blocks such as rigid surfactants and end-tethered nanorods. Varying the ratio of sphere size to rod radius stabilizes self-limited clusters and other mesostructures with reduced dimensionality. The complex phase behavior we observe is a consequence of geometric frustration.

Spectral aging analysis of the 3C 219 double-double radio galaxy

Context. Double-double radio galaxies are characterized by intermittent jet-formation activity. The exact reasons for this behavior are not yet fully understood. Studying these objects and their environment allows us to find common characteristics and compare them with the general population of radio galaxies. 3C 219 is a well-known and thoroughly studied radio galaxy. Among the many explanations for its unusual “partial jet” structure, intermittent activity seems to be the leading one. However, this hypothesis has never been tested using aging analysis. Aims. The aim of this paper is to put constraints on the active galactic nucleus duty cycle and dynamics of radio lobe expansion in 3C 219, in both the inner and outer double. This will provide us with information on the behavior of the central engine and the interaction of the radio lobes with the ambient medium, allowing us to verify whether the structure of 3C 219 is the result of intermittent activity and to search for its possible causes. Methods. We performed a spectral aging analysis of the 3C 219 double-double radio galaxy using archival Karl G. Jansky Very Large Array and Low Frequency Array data. We present detailed spectral age maps and constructed a spectral age profile. We compared ratios of linear sizes and luminosities in individual phases of activity with lobe expansion velocities in the plane of the sky derived from the age profile to infer hot-spot advance velocities through the surrounding medium and the orientation of the jet axes. Results. The galaxy shows a general asymmetry in the distribution of plasma with respect to the inferred jet axis in the original phase of activity, suggesting an influence of the intracluster medium on the formation of the radio structure. The advance speed of hot spots in the outer double is typical of classical FRII sources expanding into an ambient thermal medium, while for the inner double, the lower limit is estimated to be ∼0.28 c. The radio galaxy has experienced a very short quiescent period of no more than 2 Myr, which is ≲7% of its total lifetime. Conclusions. The most plausible explanation for the double-double radio structure in 3C 219 is a rapid jet reorientation along the line of sight, which may be the result of a minor merger. Further study of the 3C 219 inner double is needed. High-resolution maps are required to probe its structure in sufficient detail, while high-frequency observations are necessary to better constrain the durations of the quiescent and restarted phases.