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1.
Annu Rev Neurosci ; 45: 533-560, 2022 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-35803587

RESUMEN

The neocortex is a complex neurobiological system with many interacting regions. How these regions work together to subserve flexible behavior and cognition has become increasingly amenable to rigorous research. Here, I review recent experimental and theoretical work on the modus operandi of a multiregional cortex. These studies revealed several general principles for the neocortical interareal connectivity, low-dimensional macroscopic gradients of biological properties across cortical areas, and a hierarchy of timescales for information processing. Theoretical work suggests testable predictions regarding differential excitation and inhibition along feedforward and feedback pathways in the cortical hierarchy. Furthermore, modeling of distributed working memory and simple decision-making has given rise to a novel mathematical concept, dubbed bifurcation in space, that potentially explains how different cortical areas, with a canonical circuit organization but gradients of biological heterogeneities, are able to subserve their respective (e.g., sensory coding versus executive control) functions in a modularly organized brain.


Asunto(s)
Neocórtex , Cognición/fisiología , Función Ejecutiva , Memoria a Corto Plazo/fisiología , Neocórtex/fisiología , Red Nerviosa/fisiología
2.
Proc Natl Acad Sci U S A ; 121(14): e2318391121, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38527207

RESUMEN

The exploitation of novel wound healing methods with real-time infection sensing and high spatiotemporal precision is highly important for human health. Pt-based metal-organic cycles/cages (MOCs) have been employed as multifunctional antibacterial agents due to their superior Pt-related therapeutic efficiency, various functional subunits and specific geometries. However, how to rationally apply these nanoscale MOCs on the macroscale with controllable therapeutic output is still challenging. Here, a centimeter-scale Pt MOC film was constructed via multistage assembly and subsequently coated on a N,N'-dimethylated dipyridinium thiazolo[5,4-d]thiazole (MPT)-stained silk fabric to form a smart wound dressing for bacterial sensing and wound healing. The MPT on silk fabric could be used to monitor wound infection in real-time through the bacteria-mediated reduction of MPT to its radical form via a color change. The MPT radical also exhibited an excellent photothermal effect under 660 nm light irradiation, which could not only be applied for photothermal therapy but also induce the disassembly of the Pt MOC film suprastructure. The highly ordered Pt MOC film suprastructure exhibited high biosafety, while it also showed improved antibacterial efficiency after thermally induced disassembly. In vitro and in vivo studies revealed that the combination of the Pt MOC film and MPT-stained silk can provide real-time information on wound infection for timely treatment through noninvasive techniques. This study paves the way for bacterial sensing and wound healing with centimeter-scale metal-organic materials.


Asunto(s)
Platino (Metal) , Infección de Heridas , Humanos , Platino (Metal)/farmacología , Cicatrización de Heridas , Vendajes , Antibacterianos/farmacología , Antibacterianos/química , Seda/química , Bacterias , Hidrogeles/farmacología
3.
Nano Lett ; 24(22): 6576-6584, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38775216

RESUMEN

Hierarchical biobased micro/nanomaterials offer great potential as the next-generation building blocks for robust films or macroscopic fibers with high strength, while their capability in suppressing crack propagation when subject to damage is hindered by their limited length. Herein, we employed an approach to directly convert bulk wood into fibers with a high aspect ratio and nanosized branching structures. Particularly, the length of microfibers surpassed 1 mm with that of the nanosized branches reaching up to 300 µm. The presence of both interwoven micro- and nanofibers endowed the product with substantially improved tensile strength (393.99 MPa) and toughness (19.07 MJ m-3). The unique mechanical properties arose from mutual filling and the hierarchical deformation facilitated by branched nanofibers, which collectively contributed to effective energy dissipation. Hence, the nanotransformation strategy opens the door toward a facial, scalable method for building high-strength film or macroscopic fibers available in various advanced applications.

4.
Small ; : e2404526, 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39240009

RESUMEN

Macroscopic self-assembly of µm-to-mm components (dimension from 100 µm to millimeters), is meaningful to realize the concept of "self-assembly at all scales" and to understand interfacial phenomena such as adhesion, self-healing, and adsorption. However, self-assembly at this length scale is different from molecular self-assembly due to limited collision chances and binding capacity between components. Long-time contact between components is requisite to realize µm-to-mm assembly. Even though the recent idea of adding a compliant coating to enhance the molecular binding capacity is effective for such self-assembly, a trade-off between coating thickness (several micrometers) and assembly efficiency exists. Here a new compliant coating of surface-initiated polymer brush to address the above paradox by both realizing fast assembly and reducing the coating thickness to ≈40 nm by two magnitudes is demonstrated. Millimeter-sized quartz cubes are used as components and grafted with oppositely charged polyelectrolyte brushes, enabling assembly in water by electrostatic attraction and disassembly in NaCl solutions. A rule of thickness-dependent assembly chance is obtained and understood by in situ force measurements and a multivalent theory. The polymer brush strategy pushes the thickness limit of requisite compliant coating to the nanoscale for fast µm-to-mm self-assembly and provides insights into rapid wet adhesion.

5.
Small ; 20(40): e2401432, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38818686

RESUMEN

Colloidal composites, translating the great potential of nanoscale building bricks into macroscopic dimensions, have emerged as an appealing candidate for new materials with applications in optics, energy storage, and biomedicines. However, it remains a key challenge to bridge the size regimes from nanoscopic colloidal particles to macroscale composites possessing mechanical robustness. Herein, a bottom-up approach is demonstrated to manufacture colloidal composites with customized macroscopic forms by virtue of the co-assembly of nanosized soft polymeric micelles and hard inorganic nanoparticles. Upon association, the hairy micellar corona can bind with the hard nanoparticles, linking individual hard constituents together in a soft-hard alternating manner to form a collective entity. This permits the integration of block copolymer micelles with controlled amounts of hard nanoparticles into macroscopic colloidal composites featuring diverse internal microstructures. The resultant composites showed tunable microscale mechanical strength in a range of 90-270 MPa and macroscale mechanical strength in a range of 7-42 MPa for compression and 2-24 MPa for bending. Notably, the incorporation of soft polymeric micelles also imparts time- and temperature-dependent dynamic deformability and versatile capacity to the resulting composites, allowing their application in the low-temperature plastic processing for functional fused silica glass.

6.
Vet Res ; 55(1): 89, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39010163

RESUMEN

Since the reintroduction of African swine fever virus (ASFV) in Europe in 2007 and its subsequent spread to Asia, wild boar has played a crucial role in maintaining and disseminating the virus. There are significant gaps in the knowledge regarding infection dynamics and disease pathogenesis in domestic pigs and wild boar, particularly at the early infection stage. We aimed to compare domestic pigs and wild boar infected intranasally to mimic natural infection with one of the original highly virulent genotype II ASFV isolates (Armenia 2007). The study involved euthanising three domestic pigs and three wild boar on days 1, 2, 3, and 5 post-infection, while four domestic pigs and four wild boar were monitored until they reached a humane endpoint. The parameters assessed included clinical signs, macroscopic lesions, viremia levels, tissue viral load, and virus shedding in nasal and rectal swabs from day 1 post-infection. Compared with domestic pigs, wild boar were more susceptible to ASFV, with a shorter incubation period and earlier onset of clinical signs. While wild boar reached a humane endpoint earlier than domestic pigs did, the macroscopic lesions were comparatively less severe. In addition, wild boar had earlier viremia, and the virus was also detected earlier in tissues. The medial retropharyngeal lymph nodes were identified as key portals for ASFV infection in both subspecies. No viral genome was detected in nasal or rectal swabs until shortly before reaching the humane endpoint in both domestic pigs and wild boar, suggesting limited virus shedding in acute infections.


Asunto(s)
Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Genotipo , Sus scrofa , Animales , Virus de la Fiebre Porcina Africana/genética , Virus de la Fiebre Porcina Africana/fisiología , Fiebre Porcina Africana/virología , Porcinos , Esparcimiento de Virus , Viremia/veterinaria , Viremia/virología , Carga Viral/veterinaria , Virulencia
7.
Nanotechnology ; 35(33)2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38749413

RESUMEN

Self-assembly processes are widely used in nature to form hierarchically organized structures, prompting us to investigate such processes at the macroscopic scale. We report an unprecedented approach toward the self-assembly of alkyl-fullerene (C60) derivatives into a hexagonal array of hemispherical microparticles akin to the morphology of a compound eye. The method includes casting solvated alkyl-C60compound on an air/water interface followed by controlled evaporation of the solvent under atmosphere-sealed conditions. This leads to the formation of a thin film floating on water with a diameter of up to 1.3 centimeters and exhibiting a hexagonally-packed hemispherical structure with a diameter of approximately 38µm. Various measurements of the formed film reveal that amorphousness is necessary for suppressing uncontrollable crystallization, which affects the microparticle size and film formation mechanism. We tested the feasibility of this approach for the self-assembly of a relatively common C60derivative, [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM), resulting in the formation of a film with a similar pattern of hexagonally-packed larger microparticles approximately 152µm in size of diameter.

8.
Artículo en Inglés | MEDLINE | ID: mdl-39288986

RESUMEN

BACKGROUND AND AIM: Although rapid on-site cytological evaluation (ROSE) for endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA) may increase diagnostic yield, it is not widely available. Macroscopic on-site evaluation (MOSE) is an alternative modality although it is not standardized for EUS-guided fine-needle biopsy (FNB). We evaluated diagnostic performance of MOSE compared with conventional technique of EUS-TA using core biopsy needle. METHODS: Consecutive patients undergoing EUS-FNA for solid lesions were randomized to MOSE or conventional arms. The primary and secondary outcome measures were diagnostic accuracy, diagnostic yield, sensitivity, specificity, positive and negative predictive values, and the number of passes, respectively. The optimum parameters for macroscopic visible core (MVC, i.e., length, number) by MOSE to achieve accurate diagnosis were evaluated. RESULTS: Ninety-six patients (48 conventional and 48 MOSE) were enrolled. Mean lesion size was larger in MOSE arm (32.67 ± 7.22 vs 29.31 ± 6.98 mm, P = 0.023). Diagnostic accuracy (95.8% vs 91.6%), diagnostic yield (97.9% vs 95.8%), procedure duration, and adverse events of the two methods were similar. Median number of passes with MOSE was less (2 vs 3 P = 0.000). Area under the receiver operating characteristic curve showed that with MOSE, obtaining a total MVC length of 11.5 mm had 93.3% sensitivity, and 2.5 MVC cores (each 4 mm) had 86.7% sensitivity for malignancy diagnosis. CONCLUSIONS: EUS-FNB with MOSE, a simple reliable technique, can achieve a high and comparable diagnostic accuracy with lesser number of passes. Obtaining longer length and greater number of MVC increase the sensitivity to diagnose malignancy with MOSE.

9.
BMC Vet Res ; 20(1): 104, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38491459

RESUMEN

BACKGROUND: members of the genus Sarcocystis are intracellular obligate protozoan parasites classified within the phylum Apicomplexa and have an obligate heteroxenous life cycle involving two hosts. A more comprehensive understanding of the prevalence and geographic range of different Sarcocystis species in marine ecosystems is needed globally and nationally. Hence, the objective of this study was to document the incidence of Sarcocystis infection in sharks within the aquarium ecosystem of Egypt and to identify the species through the characterization of the SSU rDNA gene. METHODS: All organs of the mako shark specimen underwent macroscopic screening to detect the existence of a Sarcocystis cyst. Ten cysts were collected from the intestine and processed separately to extract the genomic DNA. The polymerase chain reaction (PCR) was accomplished by amplifying a specific 18S ribosomal RNA (rRNA) gene fragment. Subsequently, the resulting amplicons were subjected to purification and sequencing processes. RESULTS: Macroscopic examination of the mako shark intestinal wall sample revealed the presence of Sarcocystis cysts of various sizes and shapes, and sequencing of the amplicons from Sarcocystis DNA revealed a 100% nucleotide identity with the sequence of Sarcocystis tenella recorded from sheep in Iran; The mako shark sequence has been deposited in the GeneBank with the accession number OQ721979. This study presents the first scientific evidence demonstrating the presence of the Sarcocystis parasite in sharks, thereby documenting this specific marine species as a novel intermediate host in the Sarcocystis life cycle. CONCLUSIONS: This is the first identification of Sarcocystis infection in sharks, and we anticipate it will be an essential study for future screenings and establishing effective management measures for this disease in aquatic ecosystems.


Asunto(s)
Sarcocystis , Tiburones , Animales , Ovinos/genética , Sarcocystis/genética , Ecosistema , Tiburones/genética , Filogenia , Océano Índico , ADN Ribosómico , Estadios del Ciclo de Vida
10.
Chirality ; 36(1): e3622, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37795624

RESUMEN

A novel chiroptical spectrophotometer, Multichannel (MC)-circular dichroism (CD), which does not require a wavelength scan and provides artifact-free CD spectra in seconds, was developed by solving the incompatibility problem between data acquisition and modulation timescales. The design and instrumentation are compared with the Universal Chiroptical Spectrophotometer (UCS)-1, which can measure artifact-free CD spectra in the solid state. Enantiomeric single crystals composed of achiral components, α-Ni(H2 O)6 ・SO4 , and achiral films with substantial macroscopic anisotropies were measured on both MC-CD and UCS-1 and compared.

11.
Int J Clin Oncol ; 29(6): 790-800, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38512543

RESUMEN

BACKGROUND: Initial chemotherapy (Initial-C) followed by surgery is a promising treatment strategy for peritoneal lavage cytology-positive gastric cancer (CY1 GC) with no other noncurative factors. The aim of this study was to investigate the survival advantage of Initial-C compared to initial surgery (Initial-S) for this disease according to the macroscopic type, which was associated with prognosis and the efficacy of chemotherapy in GC. METHODS: One hundred eighty-nine patients who were diagnosed with CY1 GC with no other noncurative factors at four institutions from January 2007 to December 2018 were enrolled. The patients were divided into a macroscopic type 4 group (N = 48) and a non-type 4 group (N = 141). The influence of initial treatment on overall survival (OS) in each group was evaluated. RESULTS: In the type 4 group, the 5-year OS rates of Initial-C (N = 35) and Initial-S (N = 13) were 11.6% and 0%, respectively (P = 0.801). The multivariate analysis could not show the survival advantage of Initial-C. In the non-type 4 group, the 5-year OS rates of Initial-C (N = 41) and Initial-S (N = 100) were 48.4% and 29.0%, respectively (P = 0.020). The multivariate analysis revealed that Initial-C was independently associated with prolonged OS (hazard ratio, 0.591; 95% confidence interval, 0.375-0.933: P = 0.023). CONCLUSIONS: Initial-C improves the prognosis of non-type 4 CY1 GC with no other noncurative factors. On the other hand, further development of effective chemotherapeutic regimens and innovative treatment strategies are required for type 4 CY1 GC.


Asunto(s)
Lavado Peritoneal , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/patología , Neoplasias Gástricas/mortalidad , Masculino , Femenino , Persona de Mediana Edad , Anciano , Pronóstico , Estudios Retrospectivos , Adulto , Tasa de Supervivencia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Gastrectomía , Anciano de 80 o más Años , Citología
12.
BMC Biol ; 21(1): 120, 2023 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-37226182

RESUMEN

As organisms evolve, the effects of mutations change as a result of epistatic interactions with other mutations accumulated along the line of descent. This can lead to shifts in adaptability or robustness that ultimately shape subsequent evolution. Here, we review recent advances in measuring, modeling, and predicting epistasis along evolutionary trajectories, both in microbial cells and single proteins. We focus on simple patterns of global epistasis that emerge in this data, in which the effects of mutations can be predicted by a small number of variables. The emergence of these patterns offers promise for efforts to model epistasis and predict evolution.


Asunto(s)
Epistasis Genética , Mutación
13.
Sensors (Basel) ; 24(7)2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38610586

RESUMEN

We present an interferometric sensor for investigating macroscopic quantum mechanics on a table-top scale. The sensor consists of a pair of suspended optical cavities with finesse over 350,000 comprising 10 g fused silica mirrors. The interferometer is suspended by a four-stage, light, in-vacuum suspension with three common stages, which allows for us to suppress common-mode motion at low frequency. The seismic noise is further suppressed by an active isolation scheme, which reduces the input motion to the suspension point by up to an order of magnitude starting from 0.7 Hz. In the current room-temperature operation, we achieve a peak sensitivity of 0.5 fm/Hz in the acoustic frequency band, limited by a combination of readout noise and suspension thermal noise. Additional improvements of the readout electronics and suspension parameters will enable us to reach the quantum radiation pressure noise. Such a sensor can eventually be utilized for demonstrating macroscopic entanglement and for testing semi-classical and quantum gravity models.

14.
Sensors (Basel) ; 24(10)2024 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-38793934

RESUMEN

Self-assembly formation is a key research topic for realizing practical applications in swarm robotics. Due to its inherent complexity, designing high-performance self-assembly formation strategies and proposing corresponding macroscopic models remain formidable challenges and present an open research frontier. Taking inspiration from crystallization, this paper introduces a distributed self-assembly formation strategy by defining free, moving, growing, and solid states for robots. Robots in these states can spontaneously organize into user-specified two-dimensional shape formations with lattice structures through local interactions and communications. To address the challenges posed by complex spatial structures in modeling a macroscopic model, this work introduces the structural features estimation method. Subsequently, a corresponding non-spatial macroscopic model is developed to predict and analyze the self-assembly behavior, employing the proposed estimation method and a stock and flow diagram. Real-robot experiments and simulations validate the flexibility, scalability, and high efficiency of the proposed self-assembly formation strategy. Moreover, extensive experimental and simulation results demonstrate the model's accuracy in predicting the self-assembly process under different conditions. Model-based analysis indicates that the proposed self-assembly formation strategy can fully utilize the performance of individual robots and exhibits strong self-stability.

15.
Molecules ; 29(12)2024 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-38930807

RESUMEN

Squaric-acid-linked zwitterionic covalent organic frameworks (Z-COFs), assembled through interlayer interactions, are emerging as potential materials in the field of photocatalysis. However, the study of their interlayer interactions has been largely overlooked. To address this, this work systematically calculated interlayer interactions via density functional theory (DFT) and analyzed the differences in interlayer interactions of different structures of Z-COFs through interlayer slippage, planarity, and an independent gradient model based on the Hirshfeld partition (IGMH). Furthermore, it revealed the relationship between the interactions and the macroscopic photocatalytic carrier transport performance of the material. The results indicated that both preventing interlayer slippage and enhancing planarity can enhance the interlayer interactions of Z-COFs, thereby improving their macroscopic carrier transport performance in photocatalysis.

16.
Molecules ; 29(11)2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38893505

RESUMEN

Cynometra iripa Kostel. is a Fabaceae species of mangrove used in traditional Ayurvedic medicine for treating inflammatory conditions. The present study aims to establish monographic botanical and chemical quality criteria for C. iripa leaf and bark as herbal substances and to evaluate their in vitro antioxidant potential. Macroscopic and microscopic qualitative and quantitative analyses, chemical LC-UV/DAD-ESI/MS profiling, and the quantification of key chemical classes were performed. Antioxidant activity was evaluated by DPPH and FRAP assays. Macroscopically, the leaf is asymmetrical with an emarginated apex and cuneate base. Microscopically, it shows features such as two-layered adaxial palisade parenchyma, vascular bundles surrounded by 3-6 layers of sclerenchyma, prismatic calcium oxalate crystals (5.89 ± 1.32 µm) along the fibers, paracytic stomata only on the abaxial epidermis (stomatal index-20.15), and non-glandular trichomes only on petiolules. The microscopic features of the bark include a broad cortex with large lignified sclereids, prismatic calcium oxalate crystals (8.24 ± 1.57 µm), and secondary phloem with distinct 2-5 seriated medullary rays without crystals. Chemical profile analysis revealed that phenolic derivatives, mainly condensed tannins and flavonoids, are the main classes identified. A total of 22 marker compounds were tentatively identified in both plant parts. The major compounds identified in the leaf were quercetin-3-O-glucoside and taxifolin pentoside and in the bark were B-type dimeric proanthocyanidins and taxifolin 3-O-rhamnoside. The total phenolics content was higher in the leaf (1521 ± 4.71 mg GAE/g dry weight), while the total flavonoids and condensed tannins content were higher in the bark (82 ± 0.58 mg CE/g and 1021 ± 5.51 mg CCE/g dry weight, respectively). A total of 70% of the hydroethanolic extracts of leaf and bark showed higher antioxidant activity than the ascorbic acid and concentration-dependent scavenging activity in the DPPH assay (IC50 23.95 ± 0.93 and 23.63 ± 1.37 µg/mL, respectively). A positive and statistically significant (p < 0.05) correlation between the phenol content and antioxidant activity was found. The results obtained will provide important clues for the quality control criteria of C. iripa leaf and bark, as well as for the knowledge of their pharmacological potential as possible anti-inflammatory agents with antioxidant activity.


Asunto(s)
Antioxidantes , Corteza de la Planta , Extractos Vegetales , Hojas de la Planta , Corteza de la Planta/química , Hojas de la Planta/química , Antioxidantes/farmacología , Antioxidantes/química , Extractos Vegetales/química , Extractos Vegetales/farmacología , Plantas Medicinales/química , Flavonoides/química , Flavonoides/análisis , Fitoquímicos/química , Fitoquímicos/farmacología , Fitoquímicos/análisis , Medicina de Hierbas/métodos , Fenoles/análisis , Fenoles/química , Proantocianidinas/química , Proantocianidinas/análisis , Proantocianidinas/farmacología
17.
Molecules ; 29(17)2024 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-39275036

RESUMEN

Quaternary (AlxGa1-x)yIn1-yP alloys grown on GaAs substrates have recently gained considerable interest in photonics for improving visible light-emitting diodes, laser diodes, and photodetectors. With two degrees of freedom (x, y) and keeping growth on a lattice-matched GaAs substrate, the (AlxGa1-x)0.5In0.5P alloys are used for tuning structural, phonon, and optical characteristics in different energy regions from far-infrared (FIR) → near-infrared (NIR) → ultraviolet (UV). Despite the successful growth of (AlxGa1-x)0.5In0.5P/n+-GaAs epilayers, limited optical, phonon, and structural characteristics exist. Here, we report our results of carefully examined optical and vibrational properties on highly disordered alloys using temperature-dependent photoluminescence (TD-PL), Raman scattering spectroscopy (RSS), and Fourier-transform infrared reflectivity (FTIR). Macroscopic models were meticulously employed to analyze the TD-PL, RSS, and FTIR data of the (Al0.24Ga0.76)0.5In0.5P/n+-GaAs epilayers to comprehend the energy-dependent characteristics. The Raman scattering and FTIR results of phonons helped analyze the reflectivity spectra in the FIR region. Optical constants were carefully integrated in the transfer matrix method for evaluating the reflectivity R(E) and transmission T(E) spectra in the NIR → UV regions, validating the TD-PL measurements of bandgap energies (EgPL).

18.
Environ Geochem Health ; 46(11): 431, 2024 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-39316236

RESUMEN

This research work presents an examination of the concentrations and modes of occurrence of environmentally sensitive elements within lignite deposits, located in Neyveli, within the Cauvery Basin of India. Coal is one of the most complex geologically formed materials, consisting of organic and inorganic matter. The inorganic mineral matter including the crystalline minerals, non-crystalline mineraloids, and elements with non-mineral associations. These lignite samples underwent complete analysis encompassing macroscopic, microscopic and geochemical assessments. The analysis reveals that the total mineral matter (MM) content, comprising significant proportions of sulphides, carbonate and argillaceous components. Geochemical characterization further elucidates the lignite's properties, with proximate analysis yielding values such as ash, volatile matter and fixed carbon and the Ultimate components analysis reveals the carbon, hydrogen, nitrogen, sulphur and oxygen. Inorganic mineral matters play a significant role in coal utilization, and also such modes of occurrence of elements provide useful geochemical information on coal formation and coal-bearing basin evolution. In this paper, we assess the associations of elements and minerals, as well as the associations of selected elements including environmentally-sensitive (e.g., S, As, U, and Hg), and some major elements (e.g., Ca, Mg, Fe, Al, and Ti) that have largely occurred in non-mineral forms in these low-rank coals. And also, comparative analysis is conducted between the concentrations of elements within the lignite samples and the values reported for World Clarke Brown Coals (WCBC). Particularly, some of these elements exhibit significantly high environmental sensitivity, demanding careful consideration in lignite extraction and utilization practices.


Asunto(s)
Carbón Mineral , Monitoreo del Ambiente , Minerales , India , Minerales/análisis , Monitoreo del Ambiente/métodos , Sedimentos Geológicos/química
19.
Angew Chem Int Ed Engl ; : e202414683, 2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39283815

RESUMEN

Asymmetric carbon molecular sieve (CMS) hollow fiber membranes with tunable micro- and macro-structural morphologies for energy efficient propylene-propane separation are reported here.  A sub-glass transition temperature (sub-Tg) thermal oxidative crosslinking strategy enables simultaneous optimization of the intrinsic molecular sieving properties while also reducing the thickness of the CMS "skin" derived from the 6FDA:BPDA/DAM polyimide precursors. Such synergistic tuning of CMS microstructure and macroscopic morphology of CMS hollow fibers enables significantly increased propylene permeance (reaching 186.5 GPU) while maintaining an appealing propylene/propane selectivity of 13.3 for 50/50 propylene/propane mixed gas feeds. Our findings reveal a more refined and versatile tool than available with previous O2-doping pretreatments. The advanced approach here should be broadly useful to other polyimide precursors and diverse gas pairs.

20.
Angew Chem Int Ed Engl ; : e202412380, 2024 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-39180764

RESUMEN

Despite significant advancements in fabricating covalent organic frameworks (COFs) with diverse morphologies, creating COFs with superhelical nanostructures remains challenging. We report here the controlled synthesis of homochiral superhelical COF nanofibers by manipulating pendent alkyl chain lengths in organic linkers. This approach yields homochiral 3D COFs 13-OR with a 10-fold interpenetrated diamondoid structure (R = H, Me, Et, nPr, nBu) from enantiopure 1,1'-bi-2-naphthol (BINOL)-based tetraaldehydes and tetraamine. COF-13-OEt exhibits macroscopic chirality as right-handed and left-handed superhelical fibers, whereas others adopt spherical or non-helical morphologies. Time-tracking shows a self-assembly process from non-helical strands to single-stranded helical fibers and intertwined superhelices. Ethoxyl substituents, being of optimal size, balance solvophobic effects and intermolecular interactions, driving the formation of superhelical nanostructures, with handedness determined by BINOL chirality. The superhelical nature of these materials is evident in their chiral recognition and spin-filter properties, showing significantly improved enantiodiscrimination in carbohydrate binding (up to six times higher enantioselectivity) and a remarkable chiral-induced spin selectivity (CISS) effect with a 48-51% spin polarization ratio, a feature absent in non-helical analogs.

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