Molecular Architecture Research Articles

Unveiling the Genetic and Clinical Differences of Acute Myeloid Leukemia (AML) in Obese Patients.

The molecular architecture of acute myeloid leukemia (AML) is heterogeneous. Obesity has been identified as a risk factor for the development of AML. There remains a scarcity of data elucidating the specific genetic profile of AML in obese patients. We conducted a review of adult patients treated at our institution for newly diagnosed AML from January 1, 2017, to January 1, 2023. Obesity is defined as BMI > 30 kg/m2. Demographic, clinical, laboratory, and pathologic data were collected retrospectively. The primary outcome of interest was the molecular features of obese compared to non-obese AML patients. The secondary outcome was overall survival (OS). Inverse probability of treatment weights (IPTW) used to balance both groups on several confounding variables. A total of 185 patients were included in the analysis. 90 (49%) were obese. Compared with non-obese patients, obese patients were younger and more likely to be females (55 vs. 63, p = 0.04, 55% vs. 38%, p value, p = 0.02, respectively). After matching on age, gender, and ethnicity, obese patients exhibit lower rates of total number of gene mutations (median 2.7 vs. 3.2, p = 0.05), significantly lower rates of mutations in transcriptional factor genes (15.7% vs. 33.2%, p = 0.01), and near-significant in spliceosome genes (12% vs. 22.3%, p = 0.08), and higher rates of NPM1 mutation (23.3% vs. 12.6%, p = 0.08). Median OS was not significantly different in the matched cohort. The molecular features of obese AML patients significantly differ from non-obese counterparts. These findings suggest distinct underlying mechanisms in leukemogenesis in obese patients.

Spatiotemporal Molecular Architecture of Lineage Allocation and Cellular Organization in Tooth Morphogenesis.

The remarkable evolution of teeth morphological complexity represents a giant leap for vertebrate. Despite its importance in life history, the understanding of spatiotemporal organization of teeth remains rudimentary. Herein, a high-resolution genome-wide molecular patterning of lineage allocation and cellular organization in tooth morphogenesis is described, constructed by integrating spatial transcriptome and single-cell RNA sequencing. Twelve spatial compartments and seventeen heterogeneous cell clusters linked to tooth morphogenic milestones are identified. Eighty-eight percent of total lineage species has already appeared in the initial tooth bud rather than the generally considered sequential emergence. A previously unrecognized sprouting-like patterning mode of the dental papilla is discovered, that the inner compartment can break through the outer shell compartment to build up the final papilla cusp. Meanwhile, the continuum differentiation hierarchies of enamel knots in time and space are revealed. Furthermore, the regulatory network directing tooth morphogenesis is established, whereby a series of mechanotransduction signals are spatiotemporally involved beyond the well-established classical odontogenesis signals. Finally, genes underlying tooth dysplasia are successfully tracked to highly specific time points and cell types. The results raise the idea that tooth morphogenesis is orchestrated by mechanical niches combined with biochemical signaling.

EPID-09. THE NATURAL HISTORY AND MOLECULAR ARCHITECTURE OF INCIDENTAL MENINGIOMAS

Abstract The prevalence of asymptomatic, incidental meningiomas is increasing due to greater frequency of brain imaging. This retrospective cohort study of adult patients presenting at a single institution from 1996-2020 integrated clinical data, serial magnetic resonance imaging (MRI) volumetrics, DNA methylation profiling, and targeted gene expression profiling to define the natural history and molecular architecture of incidental meningiomas. Volumetrics were calculated from contrast-enhanced brain MRIs at time of diagnosis compared to serial surveillance MRIs (average 3 MRIs per patient pre-intervention, range: 1-12) DNA methylation groups and gene expression risk scores were defined for 123 samples that underwent resection. Time-to-event analyses were performed for progression-free survival (PFS), symptom-free survival (SFS), and treatment-free survival (TFS). The cohort included 238 meningiomas from 207 patients. Median age at diagnosis was 59 years and 81.5% of patients were female. Median clinical and imaging follow-up were 9.1 and 6.7 years, respectively, during which time 50.8% progressed. Median maximum diameter and volume at diagnosis were 2.20 cm and 4.25 cm3, respectively, and median pre-treatment volumetric growth rate was 19.2% per year. Median pre-treatment PFS and TFS were 3.10 and 1.27 years, respectively, and median SFS and post-treatment PFS were not reached. Cox proportional hazards regression identified maximum diameter at diagnosis as a significant predictor of worse pre-treatment PFS (multivariate HR 1.65 per 1 cm [95% CI 1.19–2.28], p=0.0027) and worse TFS (multivariate HR 1.44 per 1 cm [95% CI 1.17–1.76], p<0.001). Skull base tumors had with worse SFS (multivariate HR 2.48 [95% CI 1.02–6.00], p=0.045). Molecular and histological features among incidental meningiomas that ultimately underwent resection (n=176, 74.0%) were reassuring (89.2% WHO grade 1, 10.2% WHO grade 2). These findings suggest maximum diameter at diagnosis of incidental meningiomas is significantly associated with earlier progression and eventual treatment, and skull base tumors have earlier symptom development.

Glutamylation imbalance impairs the molecular architecture of the photoreceptor cilium.

Microtubules, composed of conserved α/β-tubulin dimers, undergo complex post-translational modifications (PTMs) that fine-tune their properties and interactions with other proteins. Cilia exhibit several tubulin PTMs, such as polyglutamylation, polyglycylation, detyrosination, and acetylation, with functions that are not fully understood. Mutations in AGBL5, which encodes the deglutamylating enzyme CCP5, have been linked to retinitis pigmentosa, suggesting that altered polyglutamylation may cause photoreceptor cell degeneration, though the underlying mechanisms are unclear. Using super-resolution ultrastructure expansion microscopy (U-ExM) in mouse and human photoreceptor cells, we observed that most tubulin PTMs accumulate at the connecting cilium that links outer and inner photoreceptor segments. Mouse models with increased glutamylation (Ccp5-/- and Ccp1-/-) or loss of tubulin acetylation (Atat1-/-) showed that aberrant glutamylation, but not acetylation loss, disrupts outer segment architecture. This disruption includes exacerbation of the connecting cilium, loss of the bulge region, and destabilization of the distal axoneme. Additionally, we found significant impairment in tubulin glycylation, as well as reduced levels of intraflagellar transport proteins and of retinitis pigmentosa-associated protein RPGR. Our findings indicate that proper glutamylation levels are crucial for maintaining the molecular architecture of the photoreceptor cilium.

Uncovering novel polyhydroxyalkanoate biosynthesis genes and unique pathway in yeast hanseniaspora valbyensis for sustainable bioplastic production

This study delves into the exploration of polyhydroxyalkanoate (PHA) biosynthesis genes within wild-type yeast strains, spotlighting the exceptional capabilities of isolate DMG-2. Through meticulous screening, DMG-2 emerged as a standout candidate, showcasing vivid red fluorescence indicative of prolific intracellular PHA granules. Characterization via FTIR spectroscopy unveiled a diverse biopolymer composition within DMG-2, featuring distinct functional groups associated with PHA and polyphosphate. Phylogenetic analysis placed DMG-2 within the Hanseniaspora valbyensis NRRL Y-1626 group, highlighting its distinct taxonomic classification. Subsequent investigation into DMG-2’s PHA biosynthesis genes yielded promising outcomes, with successful cloning and efficient PHA accumulation confirmed in transgenic E. coli cells. Protein analysis of ORF1 revealed its involvement in sugar metabolism, supported by its cellular localization and identification of functional motifs. Genomic analysis revealed regulatory elements within ORF1, shedding light on potential splice junctions and transcriptional networks influencing PHA synthesis pathways. Spectroscopic analysis of the biopolymer extracted from transgenic E. coli DMG2-1 provided insights into its co-polymer nature, comprising segments of PHB, PHV, and polyphosphate. GC-MS analysis further elucidated the intricate molecular architecture of the polymer. In conclusion, this study represents a pioneering endeavor in exploring PHA biosynthesis genes within yeast cells, with isolate DMG-2 demonstrating remarkable potential. The findings offer valuable insights for advancing sustainable bioplastic production and hold significant implications for biotechnological applications.

Effect of the Compounding Method on the Development of High-Performance Binary and Ternary Blends Based on PPE

The polymer blends are an effective strategy for materials design with new properties in the plastic industry; such features may depend on the blend components and the processing method. This study aimed to understand the effect of styrene-butadiene-styrene (SBS) content and its architecture on blends based on polyphenylene ether (PPE), high-impact polystyrene (HIPS), and SBS. In addition, this research compared and analyzed the blends formulated by different processing methods: twin-screw extrusion (TSE) and internal mixing (IM). Furthermore, three SBS copolymers, two radial and one linear (with different molecular weights), were used to produce PPE/HIPS/SBS blends, analyzing which SBS copolymer feature provides excellent viscoelasticity, thermomechanical properties, and impact resistance. The findings revealed that the melt processing method played a crucial role in Izod impact resistance of the PPE/HIPS/SBS blends, as well as the molecular architecture, molecular weight, and SBS content. The findings also demonstrated that the TSE process is more effective than the IM. Since the PPE/HIPS/SBS blends displayed higher Izod impact resistance than the PPE/HIPS or PPE/SBS binary blends, a synergistic effect of SBS and HIPS is suggested.

The cohesin complex: structure and principles of interaction with dna

Accurate duplication and separation of long linear genomic DNA molecules is associated with a number of purely mechanical problems. SMC complexes are key components of the cellular machinery that ensures decatenation of sister chromosomes and compaction of genomic DNA during division. Cohesin, one of the essential eukaryotic SMC complexes, has a typical ring structure with intersubunit pore through which DNA molecules can be threaded. The capacity of cohesin for such topological entrapment of DNA is crucial for the phenomenon of post-replicative association of sister chromatids better known as cohesion. Recently, it became apparent that cohesin and other SMC complexes are in fact motor proteins with a very peculiar movement pattern leading to the formation of DNA loops. This specific process was called loop extrusion. Extrusion underlies multiple cohesin’s functions beyond cohesion, but the molecular mechanism of the process remains a mystery. In this review, we have summarized data on the molecular architecture of cohesin, the influence of ATP hydrolysis cycle on this architecture, and the known modes of cohesin–DNA interactions. Many of the seemingly disparate facts presented here will probably be incorporated in a unified mechanistic model of loop extrusion in a not so far future.

Complexity‐Building Exhaustive Dearomatization of Benzenoid Aromatics within an ESIPT‐Initiated Three‐Step Photochemical Cascade.

AbstractDearomative cycloadditions offer rapid access to complex 3D molecular architectures, commonly via a sp2‐to‐sp3 rehybridization of two atoms of an aromatic ring. Here we report that the 6e π‐system of a benzenoid aromatic pendant could be exhaustively depleted within a single photochemical cascade. An implementation of this approach involves the initial dearomative [4+2] cycloaddition of the Excited State Intramolecular Proton Transfer (ESIPT)‐generated azaxylylene, followed by two consecutive [2+2] cycloadditions of auxiliary π moieties strategically positioned in the photoprecursor. Such photochemical cascade fully dearomatizes the benzenoid aromatic ring, saturating all six sp2 atoms to yield a complex sp3‐rich scaffold with high control of its 3D molecular shape, rendering it a robust platform for rapid systematic mapping of underexplored chemical space. Significant growth of molecular complexity—starting with a modular synthesis of photoprecursors from readily available building blocks—is quantified by Böttcher score calculations.

Synaptopodin: a key regulator of Hebbian plasticity

Synaptopodin, an actin-associated protein found in a subset of dendritic spines in telencephalic neurons, has been described to influence both functional and morphological plasticity under various plasticity paradigms. Synaptopodin is necessary and sufficient for the formation of the spine apparatus, stacks of smooth endoplasmic reticulum cisternae. The spine apparatus is a calcium store that locally regulates calcium dynamics in response to different patterns of activity and is also thought to be a site for local protein synthesis. Synaptopodin is present in ~30% of telencephalic large dendritic spines in vivo and in vitro highlighting the heterogeneous microanatomy and molecular architecture of dendritic spines, an important but not well understood aspect of neuroplasticity. In recent years, it has become increasingly clear that synaptopodin is a formidable regulator of multiple mechanisms essential for learning and memory. In fact, synaptopodin appears to be the decisive factor that determines whether plasticity can occur, acting as a key regulator for synaptic changes. In this review, we summarize the current understanding of synaptopodin’s role in various forms of Hebbian synaptic plasticity.

Photoinduced Anisotropy in Thin Films of Azobenzene-Containing Liquid Crystalline Supramolecular Complexes of Various Polymer Architecture.

Light patternable colorless liquid crystalline (LC) polymers are promising materials for functional photonic devices with broad applications in optical communication, diffractive optics, and displays. This work reports photoinduced optical anisotropy in thin films of azobenzene-containing (Azo) LC block copolymer supramolecular complexes, which can be decolorized after light patterning providing colorless patterned birefringent polymer films. The supramolecular complexes are prepared via intermolecular pyridine-phenol hydrogen bonding between a low-molecular-weight Azo phenol and host LC AB diblock and ABA triblock copolymers consisted of LC phenylbenzoate (PhM) blocks and poly(vinylpyridine) units. The molecular architecture of the host polymers and the morphological pattern formed by the complexes can affect orientational behavior of Azo groups under irradiation with linearly polarized light. Photoorientation of hydrogen-bonded Azo groups is accompanied by the cooperative orientation of non-photochromic PhM units, which form individual microphases and stabilize the orientation of Azo groups. This effect is specific for block copolymer complexes and it is absent for random copolymer complex, which is used as a reference sample. Optical anisotropy induced in films of the block copolymer complexes can be amplified by heating above the glass transition temperature and subsequent rinsing with diethyl ether allows colorless birefringent polymer films to be prepared.

Comprehensive assessment of schiff base derived from 4-Chloroaniline and 2-Formylphenol: Molecular architecture, experimental with computational bioactivity profiling, emphasizing anticancer efficacy against pulmonary and mammary carcinoma cell models

This study thoroughly analyses the structural and biological properties of a Schiff base compound synthesized from the condensation of 2-formyl phenol and 4-chloroaniline. Single crystal X-ray diffraction examination indicated that the compound crystallizes in the monoclinic space group P21/c, with unit cell parameters a = 13.4232(15) Å, b = 5.7860(6) Å, c = 14.699(2) Å, β = 106.048(6) °, and Z = 4. The molecular structure has an E configuration around the C = N double bond, with a bond length of 1.266(2) Å, and includes an intramolecular O—H⋯N hydrogen bond. Hirshfeld surface analysis elucidated intermolecular interactions inside the crystal lattice, emphasizing dominant hydrogen-hydrogen, hydrogen-chlorine, and carbon-hydrogen contacts. The chemical exhibited concentration-dependent antioxidant and anti-inflammatory effects. Studies on DNA interactions indicate van der Waals forces between the ligand and nucleic acid, whereas it demonstrated considerable binding affinity for BSA with a ΔG value of -6.9 kcal/mol. ADME study revealed values within the recommended range, indicating advantageous pharmacokinetic characteristics. PASS filter-based cytotoxicity predictions indicated significant anti-cancer efficacy against breast adenocarcinoma, small cell lung carcinoma, and lung cancer. Toxicological assessments in diverse models indicated no possible irritation to skin and ocular tissues, highlighting its safety profile for therapeutic use. This research advances our comprehension of Schiff bases with halogen substituents and their prospective uses in chemistry and biology.

Enhancing the photovoltaic performance of dithienobenzodithiophene based polymer donors through backbone fluorination and radical polymer additives

Unveiling the corresponding relationship between the molecular architecture of organic semiconductor materials and the morphology within the active layer of the organic solar cells (OSCs) is essential for the innovation of novel optical materials and the refinement of device optimization strategies to overcome the bottlenecks in efficiency. In this work, three dithieno[3,2-b]benzo[1,2-b;4,5-b’]dithiophene(DTBDT)-alt-benzothiadiazole (BT) based polymer donors (PDTBDT-F-BT, PDTBDT-F-FBT, and PDTBDT-F-2FBT) with varying fluorine atom content within their acceptor segments were designed and synthesized, and the photovoltaic performances of these polymers when blended with Y6 were meticulously investigated. Incorporating fluorine atoms into the BT segment was observed to not only incrementally increase the optical bandgap, lower the HOMO energy level, and bolster the self-aggregation of the polymer, but also effectively reduce the surface energy of the resulting polymer, thereby altering the donor-acceptor (D-A) interfacial spacing and the phase separation in the blend films as illustrated by molecular dynamic simulations and morphology characterization. As a result, the OSCs fabricated using PDTBDT-F-FBT, which incorporates a single fluorine substitution in the BT unit, demonstrated the highest power conversion efficiency (PCE) of 9.92 %. More importantly, this blend film's morphology is likely to be more conducive to the incorporation of the radical polymer additive, GDTA. This has resulted in a notable reduction in voltage loss, ultimately achieving a higher PCE of 11.55 % for the PDTBDT-F-FBT:Y6 based OSCs. This research uncovered a synergistic impact of backbone fluorination and the incorporation of radical polymer additives, which contributed to reducing the energy loss and enhancing the efficiency of OSCs from DTBDT-based polymer donors.

Linear Paired Electrolysis Enables Redox-Neutral (3 + 2) Annulation of Benzofuran with Vinyldiazo Compounds.

Electrosynthesis has emerged as a versatile and sustainable tool in organic chemistry, offering an efficient pathway for the construction of complex molecular architectures under mild and environmentally benign conditions. Traditional electrochemical approaches, however, predominantly rely on either anodic oxidation or cathodic reduction, limiting their capacity to achieve redox-neutral transformations using a single electrode. In this work, we introduce a linear paired electrolysis strategy that circumvents these limitations, enabling a redox-neutral (3 + 2) annulation of benzofuran with vinyldiazo compounds. This method facilitates the formation of benzofuran-fused tricyclic scaffolds, which are valuable in synthetic chemistry and medicinal applications. The transformation proceeds through sequential anodic oxidation and cathodic reduction, leveraging a radical cation pathway to deliver polycyclic compounds with high selectivity. The efficiency and mechanism of this process are thoroughly validated using cyclic voltammetry and in situ electrochemical mass spectrometry (EC-MS) and supported by theoretical calculations, shedding light on the potential of redox-neutral electrochemical transformations.

Y-Shaped Acceptor-π-Donor-π-Acceptor Configured Anthraquinone-Tethered Phenothiazine Molecular Scaffold for High-Performance Organic Pseudocapacitors.

For the first time acceptor-π-donor-π-acceptor (A-π-D-π-A) based Y-type organic electrode material have been designed and successfully utilized in supercapacitor (SC) application. This Y-type molecular architecture coined as AQ-Im-PTZ-Im-AQ based on anthraquinone (AQ) (A)-imidazole (Im) (π)-phenothiazine (PTZ) (D)-imidazole (Im) (π)-anthraquinone (AQ) (A) in combination with graphite foil (GF). As-fabricated PTZ-Im-AQ/GF and AQ-Im-PTZ-Im-AQ/GF electrode have shown the good energy storage properties in three-electrode supercapacitor system. Moreover, two-electrode symmetric supercapacitor (SSC) device based on AQ-Im-PTZ-Im-AQ/GF electrode exhibited specific capacitance (Csp) of 68.97 F g-1 at 1 A g-1 current density. The specific electron density (ED) of SSC was observed to be 12.06 Wh kg-1 at a specific power density (PD) of 1798.50 W kg-1. The SSC device exhibited 81.62 % of Csp retention after 5000 galvanostatic charge-discharge (GCD) cycles. For real world applications, AQ-Im-PTZ-Im-AQ/GF electrode was tested in symmetric Csp coin cell with applied potential voltage window of -0.4 to 1.0 V was found to be 112.32 F g-1 at 0.5 A g-1. Moreover, it realized high specific capacitance and high energy density of 19.66 Wh kg-1 at 891.94 W kg-1 power density. As a results, AQ-Im-PTZ-Im-AQ/GF make as an attractive electrode material for application in next-generation SCs.

Single-cell transcriptomic and proteomic analysis of Parkinson's disease brains.

Parkinson's disease (PD) is a prevalent neurodegenerative disorder, and recent evidence suggests that pathogenesis may be in part mediated by inflammatory processes, the molecular and cellular architectures of which are largely unknown. To identify and characterize selectively vulnerable brain cell populations in PD, we performed single-nucleus transcriptomics and unbiased proteomics to profile the prefrontal cortex from postmortem human brains of six individuals with late-stage PD and six age-matched controls. Analysis of nearly 80,000 nuclei led to the identification of eight major brain cell types, including elevated brain-resident T cells in PD, each with distinct transcriptional changes in agreement with the known genetics of PD. By analyzing Lewy body pathology in the same postmortem brain tissues, we found that α-synuclein pathology was inversely correlated with chaperone expression in excitatory neurons. Examining cell-cell interactions, we found a selective abatement of neuron-astrocyte interactions and enhanced neuroinflammation. Proteomic analyses of the same brains identified synaptic proteins in the prefrontal cortex that were preferentially down-regulated in PD. By comparing this single-cell PD dataset with a published analysis of similar brain regions in Alzheimer's disease (AD), we found no common differentially expressed genes in neurons but identified many shared differentially expressed genes in glial cells, suggesting that the disease etiologies, especially in the context of neuronal vulnerability, in PD and AD are likely distinct.

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.

A C3‐symmetric like structurally twisted molecular architecture: mechano/fluorochromic behavior and selective multiphase detection of Pd (II)

Triaminoguanidinium (TG)‐based C3‐symmetric‐like molecular architectures with diverse donors and acceptors are well established as organic molecular materials for promising stimuli‐responsive and metal sensing‐based applications. However, the mechanofluorochromic (MFC) response was unremarkable upon applying external mechanical stress. Even though some show MFC features, there was no optical shift under ambient light. In this paper, we developed a novel C3‐symmetric molecule, TAC3, containing the TG core linked with conformationally twisted thiophene‐linked anthracenyl terminals. Three conformationally deformed hands in TAC3 respond against external mechanical stimuli with a redshifted absorption and emission, easily detectable through the naked eye. Although MFC features were reported before for such C3‐symmetric molecules, the change in absorbance was not identified. In addition, TAC3 could selectively detect Pd2+ through extreme emission quenching (green to black). The mechanochromism and sensing outcomes are elucidated by the experimental and theoretical support. Compared to the previous reports, the notable 2:3 (metal: ligand) binding due to geometric restriction creating a specific pocket size for Pd+2 is unusual for this system. The onsite application on Pd2+ detection and measurable MFC features are demonstrated to validate the potential of this C3‐symmetric molecule in advanced optoelectronic applications such as security writing and Pd2+ ion detection.

Photochemical Fluoroalkylation and Alkylthiolation of O‐Cyano and O‐Alkynyl Acrylamides: Pendant Functionality Led Divergence in Annulations

AbstractA visible‐light‐mediated, organophotocatalyzed cascade perfluoroalkylation and alkylthiolation of o‐cyano and o‐alkynyl acrylamides is reported. The reaction exhibits wide scope and provides polyfluorinated 1,3‐quinoline diones and trifluoromethylated fused tricyclic quinolinones under mild reaction conditions and in good yields. Access to a variety of molecular architectures and the synthetic application of aliphatic thiols are the highlights of this reactivity manifold.

Pinwheel-like Curved Aromatics from the Cyclotrimerization of Strained Alkyne Cycloparaphenylenes.

Carbon nanomaterials composed of curved aromatics, such as carbon nanotubes, are difficult to selectively synthesize and modify precisely. Smaller molecular fragments of curved nanomaterials, such as cycloparaphenylenes, benefit from the precision of bottom-up synthesis, however, efforts to expand the curved molecular framework into even larger structures often rely on restrictive early stage synthetic strategies or difficult to control polymerizations. In this work we report a high yielding, strain-promoted, late-stage modification of a series of [n + 1]CPPs. We show that the conversion of these [n + 1]CPPs into soluble, pinwheel-like multipore carbon nanostructures is achievable via a straightforward and efficient metal-mediated alkyne cyclotrimerization reaction. We provide insight into suitable metals for this transformation, the photophysics of these trimeric molecules, as well as their strain profiles and crystal packing. We also demonstrate the strain-enhanced nature of the reaction under the optimized conditions, showing that strained internal-alkyne [n + 1]CPPs efficiently undergo complete conversion whereas unstrained diphenylacetylene remains completely unreacted. We anticipate that this work will have broader impacts on the study of reactivity in strained-alkyne-containing hydrocarbons, and that access to this new molecular architecture will inspire new research and applications in materials science and related fields.

Impact of molecular architecture and draw ratio on enhancement of targeted mechanical properties of machine direction oriented polyethylene films produced after blown film extrusion

Conventional multi-material multi-layer flexible packaging offers excellent properties. However, it has recycling challenges, necessitating a shift to mono-material multi-layer flexible packaging for example all-polyethylene (PE) packaging which can be tailored through various synthesis and processing methods for different layers. In this work, we study how the key molecular properties (number-average molecular weight ( Mn), weight-average molecular weight ( M w), molecular weight distribution (MWD), comonomer content (short chain branching)) and machine direction orientation (MDO) process draw ratio (MDX) influence the final morphology and mechanical properties of MDO-PE films which are intended as the outer layer of mono-material all-polyethylene multi-layer flexible packaging. Five PE grades and various blends were extruded and blown into films. Selected blown films were machine direction oriented to obtain the final MDO-PE films. Furthermore, one selected PE blown film was processed at different MDO process draw ratios while keeping other process parameters constant. From the molecular properties point of view, the higher molecular weight fractions provide a higher possibility for uniform stretching whereas lower molecular weight fractions provide a higher natural draw ratio and therefore higher modulus and stiffness enhancement. Further, the results show that increasing MDO process draw ratio leads to more fibrillation and increased crystallinity. Consequently, the tensile modulus and stiffness at the higher draw ratios increase as well and are comparable to conventionally used polymers in outer layers of multilayer flexible packaging. Thus, this work demonstrates that MDO-PE films with enhanced modulus can provide sufficient stiffness for the design of outer layer of mono-material multi-layer all-PE packaging which presents higher potential for mechanical recyclability.