Hydrogen (H2) is one of the next-generation energy sources because it is abundant in nature and has a high combustion efficiency that produces environmentally benign products (H2O). However, H2/air ...mixtures are explosive at H2 concentrations above 4%, thus any leakage of H2 must be rapidly and reliably detected at much lower concentrations to ensure safety. Among the various types of H2 sensors, chemiresistive sensors are one of the most promising sensing systems due to their simplicity and low cost. This review highlights the advances in H2 chemiresistors, including metal-, semiconducting metal oxide-, carbon-based materials, and other materials. The underlying sensing mechanisms for different types of materials are discussed, and the correlation of sensing performances with nanostructures, surface chemistry, and electronic properties is presented. In addition, the discussion of each material emphasizes key advances and strategies to develop superior H2 sensors. Furthermore, recent key advances in other types of H2 sensors are briefly discussed. Finally, the review concludes with a brief outlook, perspective, and future directions.
High‐entropy alloys (HEAs) provide unprecedented physicochemical properties over unary nanoparticles (NPs). According to the conventional alloying guideline (Hume–Rothery rule), however, only ...size‐and‐structure similar elements can be mixed, limiting the possible combinations of alloying elements. Recently, it has been reported that based on carbon thermal shocks (CTS) in a vacuum atmosphere at high temperature, ultrafast heating/cooling rates and high‐entropy environment play a critical role in the synthesis of HEAs, ruling out the possibility of phase separation. Since the CTS requires conducting supports, the Joule‐heating efficiencies rely on the carbon qualities, featuring difficulties in uniform heating along the large area. This work proposes a photo‐thermal approach as an alternative and innovative synthetic method that is compatible with ambient air, large‐area, remote process, and free of materials selection. Single flash irradiation on carbon nanofibers induced momentary high‐temperature annealing (>1800 °C within 20 ms duration, and ramping/cooling rates >104 K s−1) to successfully decorate HEA NPs up to nine elements with excellent compatibility for large‐scale synthesis (6.0 × 6.0 cm2 of carbon nanofiber paper). To demonstrate their feasibility toward applications, senary HEA NPs (PtIrFeNiCoCe) are designed and screened, showing high activity (ηoverall = 777 mV) and excellent stability (>5000 cycles) at the water splitting, including hydrogen evolution reactions and oxygen evolution reactions.
The flash‐thermal shock (FTS)‐driven synthesis of high‐entropy alloy (HEA) nanoparticles on carbon nanofibers and other 2D materials is presented. In particular, the FTS method merits scalability (6.0 × 6.0 cm2), rapid synthesis (>1800 °C within 20 ms duration, and ramping/cooling rates >104 K s−1), and ambient air processing. To prove their practical utility, high electrocatalytic activities in the hydrogen evolution and oxygen evolution reactions are demonstrated.
Conductive porous materials having a high surface reactivity offer great promise for a broad range of applications. However, a general and scalable synthesis of such materials remains challenging. In ...this work, the facile synthesis of catalytic metal nanoparticles (NPs) embedded in 2D metal–organic frameworks (MOFs) is reported as highly active and conductive porous materials. After the assembly of 2D conductive MOFs (C‐MOFs), i.e., Cu3(hexahydroxytriphenylene)2 Cu3(HHTP)2, Pd or Pt NPs are functionalized within the cavities of C‐MOFs by infiltration of metal ions and subsequent reduction. The unique structure of Cu3(HHTP)2 with a cavity size of 2 nm confines the bulk growth of metal NPs, resulting in ultra‐small (≈2 nm) and well‐dispersed metal NPs loaded in 2D C‐MOFs. The Pd or Pt NPs‐loaded Cu3(HHTP)2 exhibits remarkably improved NO2 sensing performance at room temperature due to the high reactivity of catalytic metal NPs and the high porosity of C‐MOFs. The catalytic effect of Pd and Pt NPs on NO2 sensing of Cu3(HHTP)2, in terms of reaction rate kinetics and activation energy, is demonstrated.
Ultra‐small and well‐dispersed metal nanoparticles (NPs) are embedded in the cavities of 2D conductive metal–organic frameworks (C‐MOFs), for the synthesis of highly active and porous conductive materials. The catalytic metal NPs‐loaded C‐MOFs exhibit dramatically improved NO2 sensing performance at room temperature, due to the high reactivity of catalytic metal NPs and the high porosity of the electrically conductive MOFs.
Plants-releasing exosome-like nanovesicles (PENs) contain miRNA, bioactive lipids, mRNAs, and proteins to exert antioxidant, anti-inflammatory, and regenerative activity. Substances extracted from ...yams have been reported to promote osteoblast growth in bone regeneration, which prevent weak and brittle bones in osteoporosis. Herein, we describe the beneficial effects of yam-derived exosome-like nanovesicles (YNVs) on promoting differentiation and mineralization of osteoblasts for bone regeneration in ovariectomized (OVX)-induced osteoporotic mice. YNVs were successfully isolated and characterized. YNVs stimulate the proliferation, differentiation, and mineralization of osteoblasts with increased bone differentiation markers (OPN, ALP, and COLI). Interestingly, YNVs do not contain saponins including diosgenin and dioscin known to mainly exert osteogenic activity of yams. Instead, the osteogenic activity of YNVs was revealed to be resulted from activation of the BMP-2/p-p38-dependent Runx2 pathway. As a result, YNVs promote longitudinal bone growth and mineral density of the tibia in the OVX-induced osteoporotic mice in vivo, and these results positively correlate the significant increases in osteoblast-related parameters. In addition, the orally administered YNVs were transported through the GI tract and absorbed through the small intestine. These results showed an excellent systemic biosafety determined by histological analysis and liver/kidney toxicity tests. Taken together, YNVs can serve as a safe and orally effective agent in the treatment of osteoporosis.
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•Isolation of PENs to prepare YNVs containing RNAs, proteins, and lipids is optimized.•Yam-derived exosome-like nanovesicles (YNVs) to promote differentiation and mineralization of osteoblasts•YNVs-mediated osteogenic differentiation is related to mechanism of BMP-2/p-p38-dependent Runx2 pathway.•YNVs promote longitudinal bone growth in the OVX-induced osteoporotic mice.
PtO2 nanocatalysts-loaded SnO2 multichannel nanofibers (PtO2-SnO2 MCNFs) were synthesized by single-spinneret electrospinning combined with apoferritin and two immiscible polymers, i.e., ...poly(vinylpyrrolidone) and polyacrylonitrile. The apoferritin, which can encapsulate nanoparticles within a small inner cavity (8 nm), was used as a catalyst loading template for an effective functionalization of the PtO2 catalysts. Taking advantage of the multichannel structure with a high porosity, effective activation of catalysts on both interior and exterior site of MCNFs was realized. As a result, under high humidity condition (95% RH), PtO2-SnO2 MCNFs exhibited a remarkably high acetone response (R air/R gas = 194.15) toward 5 ppm acetone gases, superior selectivity to acetone molecules among various interfering gas species, and excellent stability during 30 cycles of response and recovery toward 1 ppm acetone gases. In this work, we first demonstrate the high suitability of multichannel semiconducting metal oxides structure functionalized by apoferritin-encapsulated catalytic nanoparticles as highly sensitive and selective gas-sensing layer.
Interfacial engineering of organic–inorganic halide perovskites in conjunction with different functional materials is anticipated to offer novel heterojunction structures with unique functionalities. ...Unfortunately, complex material compositions and structures of the organic–inorganic hybrid materials make it difficult to tailor a desirable intermolecular interaction at the interface. Spontaneous and highly specific nucleation of perovskite crystals, that is, methylammonium lead iodide perovskite (CH3NH3PbI3, MAPbI3) at nitrogen‐doped carbon nanotube (NCNT) surfaces for the self‐assembly of MAPbI3/NCNT hybrids is reported. It is demonstrated that the lone‐pair electrons of pyridinic nitrogen‐dopant sites at NCNTs mediate specific interactions with the cationic component in the perovskite structure and serve as the nucleation sites via coordinate bonding formation, as supported by X‐ray photoelectron spectroscopy and density functional theory calculation. The potential suitability of MAPbI3/NCNT hybrids is presented for highly sensitive and selective NO2 sensing layer. This work suggests a reliable self‐assembly route to the molecular level hybridization of organic–inorganic halide perovskites by employing the substitutional dopant sites at graphene‐based nanomaterials.
The specific nucleation site and interfacial interaction between methylammonium lead iodide perovskite (CH3NH3PbI3, MAPbI3) and nitrogen‐doped carbon nanotube (NCNT) are demonstrated by experimental and theoretical analysis. The methylammonium ion is modified by sharing a proton with a pyridinic N‐dopant site for interfacial interaction. The MAPbI3/NCNT hybrids exhibit sensitive and selective NO2 sensing activities.
Bone mineral content (BMC) values in certain bones and changes in BMC over time are key features for diagnosing osteoporosis. This study examined those features using morphometric texture analysis in ...chest computational tomography (CT) by comparing a dual-energy X-ray absorptiometry (DXA)-based BMC. An accessible approach for screening osteoporosis was suggested by accessing BMC using only Hounsfield units (HU).
The study included a total of 510 cases (255 patients) acquired between May 6, 2012, and June 30, 2020, at a single institution. Two cases were associated with two chest CT scans from one patient with a scan interval of over two years, and each scan was followed soon after by a DXA scan. Axial cuts of the first lumbar vertebra in CT and DXA-based L1 BMC values were corrected for each case. The maximum trabecular area was selected from the L1 spine body, and 45 texture features were extracted from the region using gray-level co-occurrence matrices. A regression model was employed to estimate the absolute BMC value in each case using 45 features. Also, an additional regression model was used to estimate the change in BMC between two scans for each patient using 90 features from the corresponding cases.
The correlation coefficient (CC) and mean absolute error (MAE) between estimates and DXA references were obtained for the evaluation of regressors. In the case of the BMC estimation, CC and MAE were 0.754 and 1.641 (g). In the case of the estimation of change in BMC, CC and MAE were 0.680 and 0.528 (g).
The modality using morphometric texture analysis with CT HUs can indirectly help screening osteoporosis because it provides estimates of BMC and BMC change that show moderate positive correlations with DXA measures.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
As strenuous research works approach the theoretical limits of the lithium-ion battery, the need to exploit more sustainable chemistries has emerged as a primary concern. The development of the ...lithium-sulfur (Li-S) battery offers an energy density of 2567 W h kg
−1
, reflecting an up to three to fivefold enhancement against the state-of-the-art Li-ion device. Solving the critical degradation of the metal anode and suppressing correlated side reactions in the Li-S cell represent, however, pivotal steps towards commercial consideration. In light of the unique Li-S electrochemistry, we examine herein the technical challenges of the lithium metal anode, including the dendritic lithium nucleation and growth during Li plating, and the stabilization of the solid electrolyte interphase (SEI). We revisit key contributions to establish a guideline of crucial factors determining the stability of the anode and its correlation with the electrolyte selection, electrode current density, and the effect of the shuttle of polysulfide intermediate species. Most importantly, our review delivers a comprehensive comparison of introduced strategies for the metal surface protection (including electrolyte-modification-based approaches and metal surface coating), along with a theoretical understanding and analysis of the underlying methodologies. This review sheds light on future opportunities towards a practical application of Li-S batteries, while stimulating progress in the exploitation of lithium metal anodes in parallel technologies in the development of energy storage for a sustainable future (266 citations).
Critical challenges of Li-S batteries are related with the instability of Li metal during cycling. To overcome these issues, electrolyte modification and artificial SEI layer incorporation-based strategies have been here reviewed.
Hemp (Cannabis sativa L.) is used for medicinal purposes owing to its anti-inflammatory and antioxidant activities. We evaluated the protective effect of nanovesicles isolated from hemp plant parts ...(root, seed, hemp sprout, and leaf) in dextran sulfate sodium (DSS)-induced colitis in mice. The particle sizes of root-derived nanovesicles (RNVs), seed-derived nanovesicles (SNVs), hemp sprout-derived nanovesicles (HSNVs), and leaf-derived nanovesicles (LNVs) were within the range of 100–200 nm as measured by nanoparticle tracking analysis. Acute colitis was induced in C57BL/N mice by 5% DSS in water provided for 7 days. RNVs were administered orally once a day, leading to the recovery of both the small intestine and colon lengths. RNVs, SNVs, and HSNVs restored the tight (ZO-1, claudin-4, occludin) and adherent junctions (E-cadherin and α-tubulin) in DSS-induced small intestine and colon injury. Additionally, RNVs markedly reduced NF-κB activation and oxidative stress proteins in DSS-induced small intestine and colon injury. Tight junction protein expression and epithelial cell permeability were elevated in RNV-, SNV-, and HSNV-treated T84 colon cells exposed to 2% DSS. Interestedly, RNVs, SNVs, HSNVs, and LNVs reduced ALT activity and liver regeneration marker proteins in DSS-induced liver injury. These results showed for the first time that hemp-derived nanovesicles (HNVs) exhibited a protective effect on DSS-induced gut leaky and liver injury through the gut–liver axis by inhibiting oxidative stress marker proteins.
The interaction between light and matter is the fundamental aspect of many optoelectronic applications. The efficiency of such devices is mainly dictated by the light emitting properties of ...fluorophores. Unfortunately, the intensity of emission is adversely affected by surface defects, scattering and chemical instability. Therefore, enhancing the luminescence of fluorophores is necessary for better implementation of nanocomposites in biological and optical applications. There are many interesting phenomena which can be observed if the characteristics of the fluorophores and metal nanoparticles are integrated. Photoluminescence (PL) by fluorophores can be enhanced or quenched by the presence of neighboring plasmonic metal nanostructures. An unambiguous study of the mechanism behind the enhancement and the quenching of emission is necessary to obtain new insight into the interactions between light and metal-fluorophore nanocomposites. In this review the core aspect of combining plasmonic metal nanostructures with fluorophores is discussed by considering various functional roles of plasmonic metals in modifying the PL properties reported by various research groups. A few representative applications of SPR mediated luminescence are also discussed.
Surface plasmon resonance mediated light emission properties and their applications for biomedical theranosis and display devices are discussed comprehensively.
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