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Nanotechnology Jun 2024Memristors have recently received substantial attention because of its promising and unique application scenes emerging in neuromorphic computing which can achieve gains...
Memristors have recently received substantial attention because of its promising and unique application scenes emerging in neuromorphic computing which can achieve gains in computation speed by mimicking the topology of brains in electronic circuits. Traditional memristors made of bulk MoO3 and HfO2, etc. suffer from low switching ratio, short durability and poor stability. In this work, a floating-gate memristor is developed based on a mixed-dimensional heterostructure which is comprised of two-dimensional (2D) molybdenum disulfide (MoS2) and 0-dimensional (0D) Au nanoparticles (AuNPs) separated by an insulating hexagonal boron nitride (h-BN) layer, hereafter, MoS2/h-BN/AuNPs. We find that under the modulation of back-gate voltages, the MoS2/h-BN/AuNPs device operates reliably between a high resistance state (HRS) and a low resistance state (LRS) and that it shows multiple stable LRS states, demonstrating high potential of our memristor in application of multibit storage. The modulation effect can be attributed to the electron quantum tunneling between the AuNPs charge-trapping layer and MoS2 channel. Our memristor exhibits excellent durability and stability: the HRS and LRS remain more than 104 s without obvious degradation and the on/off ratio retains > 104 after more than 3000 switching cycles. We also demonstrate frequency-dependent memory properties upon electrical and optical pulse stimuli.
PubMed: 38941985
DOI: 10.1088/1361-6528/ad5cfc -
Nanotechnology Jun 2024In this research, we report an enhanced sensing response ethanol gas sensing device based on a ternary nanocomposite of molybdenum diselenide-zinc oxide heterojunctions...
In this research, we report an enhanced sensing response ethanol gas sensing device based on a ternary nanocomposite of molybdenum diselenide-zinc oxide heterojunctions decorated rGO (MoSe2/ZnO/rGO) at room temperature. The sensing performance of the ternary nanocomposite sensing device has been analysed for various concentrations of ethanol gas (1-500 ppm). The gas-sensing results have revealed that for 500 ppm ethanol gas concentration, the sensing device has exhibited an enhanced response value (Rg/Ra) of 50.2. Significantly, the sensing device has displayed a quick response and recovery time of 6.2 s and 12.9 s respectively. In addition to this, the sensing device has shown a great prospect for long-term detection of ethanol gas (45 days). The sensing device has demonstrated the ability to detect ethanol at remarkably low concentrations of 1 ppm. The enhanced sensing performance of the ternary nanocomposite sensing device has highlighted the effective synergistic effect between MoSe2 nanosheets, ZnO nanorods, and rGO nanosheets. This has been attributed to the formation of two heterojunctions in the ternary nanocomposite sensor: a p-n heterojunction between MoSe2 and ZnO and a p-p heterojunction between MoSe2 and rGO. The analysis of the results has suggested that the proposed MoSe2/ZnO/rGO nanocomposite sensing device could be considered a promising candidate for the real-time detection of ethanol gas.
PubMed: 38941983
DOI: 10.1088/1361-6528/ad5cf9 -
Scientific Reports Jun 2024Systemic Immune Inflammatory Index (SII) is a novel indicator of inflammation. However, no studies have reported the effect of SII on the association between metals and...
Systemic Immune Inflammatory Index (SII) is a novel indicator of inflammation. However, no studies have reported the effect of SII on the association between metals and total fat (TOFAT). We aim to investigate the mediated effect of SII on the relationship between urinary metals and TOFAT in a US adult population. This cross-sectional study was conducted among adults with complete information on SII, urine metal concentrations, and TOFAT from the 2011-2018 National Health and Nutrition Examination Survey (NHANES). Multifactorial logistic regression and restricted cubic splines were used to explore the association between urine metal levels and TOFAT. Furthermore, serial mediation analyses were used to investigate the mediating effect of SII on metals and TOFAT. A total of 3324 subjects were included in this study. After adjusting for confounders, arsenic (As), cadmium (Cd), cobalt (Co), cesium (Cs), inorganic mercury (Hg), molybdenum (Mo), manganese (Mn), lead (Pb), antimony (Sb), and thallium(Tl) had negative decreased trends of odds ratios for TOFAT (all P for trend < 0.05). In the total population, we found that Cd, Co, and Tu were positively associated with SII (β = 29.70, 79.37, and 31.08), whereas As and Hg had a negative association with SII. The mediation analysis showed that SII mediated the association of Co with TOFAT, with the β of the mediating effect being 0.9% (95%CI: 0.3%, 1.6%). Our findings suggested that exposure to As, Cd, and Hg would directly decrease the level of TOFAT. However, Co would increase TOFAT, completely mediated by SII, mainly exerted in females rather than males.
Topics: Humans; Female; Male; Adult; Nutrition Surveys; Inflammation; Middle Aged; Cross-Sectional Studies; Metals
PubMed: 38942999
DOI: 10.1038/s41598-024-65925-1 -
Biological Trace Element Research Jun 2024Metals are used in orthopedic implants. The wear of arthroplasty implant can lead to the release of arthroprosthetic metals, both locally and systemically, after...
Metals are used in orthopedic implants. The wear of arthroplasty implant can lead to the release of arthroprosthetic metals, both locally and systemically, after migration into the organs. While the toxicity of metal-on-metal arthroplasty implants is well-known and monitored, the toxicity associated with metal-on-polyethylene (MoP) ones is not as comprehensively understood. This study aimed to investigate the release of metals from MoP arthroplasty implants and their impact on the tissue metal profile in autopsied individuals, comparing them to deceased controls without prostheses. High-resolution ICP-MS was employed to analyze 39 metals in the blood, urine, hair, organs, and periprosthetic tissue of 25 deceased individuals with arthroplasty implants and 20 control subjects (Prometox study, protocol ID: APHP180539, NCT03812627). Eight metals (beryllium, chromium, cobalt, lanthanum, molybdenum, nickel, tellurium, titanium) exhibited significant impacts in arthroplasty implant wearers across various organs. Increased concentrations of La and Be were observed, the origin of which could not be precisely defined within the scope of this study. Notably, the lungs emerged as the primary target organ for metallic ions contained in implants. This study suggests that MoP arthroplasty implants, even when functional and not visibly worn, release arthroprosthetic metals into the body, potentially causing disturbances. Furthermore, considering the presence of an arthroplasty implant in autopsy reports may be relevant, as the released metals could influence the tissue metal profile.
PubMed: 38941062
DOI: 10.1007/s12011-024-04278-2 -
Journal of the American Chemical Society Jun 2024The iron-molybdenum cofactor of nitrogenase (FeMoco) catalyzes fixation of N via Fe hydride intermediates. Our understanding of these species has relied heavily on the...
The iron-molybdenum cofactor of nitrogenase (FeMoco) catalyzes fixation of N via Fe hydride intermediates. Our understanding of these species has relied heavily on the characterization of well-defined 3d metal hydride complexes, which serve as putative spectroscopic models. Although the Fe ions in FeMoco, a weak-field cluster, are expected to adopt locally high-spin Fe configurations, synthetically accessible hydride complexes featuring d or d electron counts are almost exclusively low-spin. We report herein the isolation of a terminal hydride complex of four-coordinate, high-spin (d; = 5/2) Mn. Electron paramagnetic resonance and electron-nuclear double resonance studies reveal an unusually large degree of spin density on the hydrido ligand. In light of the isoelectronic relationship between Mn and Fe, our results are expected to inform our understanding of the valence electronic structures of reactive hydride intermediates derived from FeMoco.
PubMed: 38940813
DOI: 10.1021/jacs.4c03310 -
Nanoscale Jun 2024Thanks to their intrinsic properties, multifunctionality and unique geometrical features, two-dimensional nanomaterials have been used widely as reinforcements in... (Review)
Review
Thanks to their intrinsic properties, multifunctionality and unique geometrical features, two-dimensional nanomaterials have been used widely as reinforcements in polymer nanocomposites. The effective mechanical reinforcement of polymers is, however, a multifaceted problem as it depends not only on the intrinsic properties of the fillers and the matrix, but also upon a number of other important parameters. These parameters include the processing method, the interfacial properties, the aspect ratio, defects, orientation, agglomeration and volume fraction of the fillers. In this review, we summarize recent advances in the mechanical reinforcement of polymer nanocomposites from two-dimensional nanofillers with an emphasis on the mechanisms of reinforcement. Model, bulk and hybrid polymer nanocomposites are reviewed comprehensively. The use of Raman and photoluminescence spectroscopies is examined in light of the distinctive information they can yield upon stress transfer at interfaces. It is shown that the very diverse family of 2D nanofillers includes a number of materials that can attribute distrinctive features to a polymeric matrix, and we focus on the mechanical properties of both graphene and some of the most important 2D materials beyond graphene, including boron nitride, molybdenum disulphide, other transition metal dichalcogenides, MXenes and black phosphorous. In the first part of the review we evaluate the mechanical properties of 2D nanoplatelets in "model" nanocomposites. Next we examine how the performance of these materials can be optimised in bulk nanocomposites. Finally, combinations of these 2D nanofillers with other 2D nanomaterials or with nanofillers of other dimensions are assessed thoroughly, as such combinations can lead to additive or even synergistic mechanical effects. Existing unsolved problems and future perspectives are discussed.
PubMed: 38940686
DOI: 10.1039/d4nr01356e -
ACS Applied Materials & Interfaces Jun 2024Skin injuries and wounds present significant clinical challenges, necessitating the development of advanced wound dressings for efficient wound healing and tissue...
Skin injuries and wounds present significant clinical challenges, necessitating the development of advanced wound dressings for efficient wound healing and tissue regeneration. In this context, the advancement of hydrogels capable of counteracting the adverse effects arising from undesirable reactive oxygen species (ROS) is of significant importance. This study introduces a hybrid hydrogel with rapid photocuring and excellent conformability, tailored to ameliorate the hostile microenvironment of damaged skin tissues. The hybrid hydrogel, composed of photoresponsive Gelatin Methacryloyl (GelMA) and Molybdenum-based nanoclusters (MNC), exhibits physicochemical characteristics conductive to skin regeneration. In vitro studies demonstrated the cytocompatibility and ROS-responsive behavior of the MNC/GelMA hybrid hydrogels, confirming their ability to promote human dermal fibroblasts (HDF) functions. The incorporation of MNC into GelMA not only enhances HDF adhesion, proliferation, and migration but also shields against oxidative damage induced by hydrogen peroxide (HO). Notably, in vivo evaluation in murine full-thickness skin defects revealed that the application of hybrid hydrogel dressings led to reduced inflammation, accelerated wound closure, and enhanced collagen deposition in comparison to control groups. Significantly, this study introduced a convenient approach to develop in situ ROS-scavenging hydrogel dressings to accelerate the wound healing process without the need for exogenous cytokines or medications. We consider that the nanoengineering approach proposed herein offers potential possibilities for the development of therapeutic hydrogel dressings addressing various skin-related conditions.
PubMed: 38934374
DOI: 10.1021/acsami.4c05636 -
Headache Jun 2024The aim of the study was to determine the heavy metal and trace element (HMTE) profile in patients with migraine (PwM) and to compare it to that of healthy individuals...
OBJECTIVE
The aim of the study was to determine the heavy metal and trace element (HMTE) profile in patients with migraine (PwM) and to compare it to that of healthy individuals without migraine.
BACKGROUND
Migraine is a universal disease that affects more than 10% of the world's population; however, its pathophysiology is still obscure.
METHODS
A total of 100 participants were included in this prospective matched case-control study (50 PwM during acute attack and 50 age- and sex-matched healthy controls). The study was conducted in the university hospital in Yozgat, Turkey, where the inductively coupled plasma mass spectrometry system was used to measure the HMTE profile. The calibration curve was created with 11 points for heavy metals (arsenic [As], cadmium [Cd], cobalt [Co], lead [Pb], mercury [Hg], nickel [Ni], and tin [Sn]) and trace elements (antimony [Sb], chromium [Cr], copper [Cu], iron [Fe], magnesium [Mg], manganese [Mn], molybdenum [Mo], and zinc [Zn]).
RESULTS
The median age was 27 (23-37) years, and the female/male ratio was 37/13 for both groups. The PwM group had significantly higher As, Co, Pb, and Ni levels among the heavy metals (p = 0.033, 0.017, 0.022, and 0.021, respectively). Also, PwM had significantly lower Cr, Mg, and Zn levels among the trace elements (p = 0.007, 0.024, and < 0.001, respectively). The only trace element that was elevated in the PwM group was Mn (p = 0.001). The PwM and control groups did not differ in terms of Cd, Sn, Sb, Cu, Fe, and Mo (p = 0.165, 0.997, 0.195, 0.408, 0.440, and 0.252, respectively).
CONCLUSION
Some HMTE parameters are altered in PwM, which may provide additional insight into understanding migraine etiology.
PubMed: 38932625
DOI: 10.1111/head.14748 -
Molecules (Basel, Switzerland) Jun 2024Electrochemical nitrate reduction (NORR) has been recognized as a promising strategy for sustainable ammonia (NH) production due to its environmental friendliness and...
Electrochemical nitrate reduction (NORR) has been recognized as a promising strategy for sustainable ammonia (NH) production due to its environmental friendliness and economical nature. However, the NORR reaction involves an eight-electron coupled proton transfer process with many by-products and low Faraday efficiency. In this work, a molybdenum oxide (MoO)-decorated titanium dioxide nanotube on Ti foil (Mo/TiO) was prepared by means of an electrodeposition and calcination process. The structure of MoO can be controlled by regulating the concentration of molybdate during the electrodeposition process, which can further influence the electron transfer from Ti to Mo atoms, and enhance the binding energy of intermediate species in NORR. The optimized Mo/TiO-M with more Mo(IV) sites exhibited a better activity for NORR. The Mo/TiO-M electrode delivered a NH yield of 5.18 mg h cm at -1.7 V vs. Ag/AgCl, and exhibited a Faraday efficiency of 88.05% at -1.4 V vs. Ag/AgCl. In addition, the cycling test demonstrated that the Mo/TiO-M electrode possessed a good stability. This work not only provides an attractive electrode material, but also offers new insights into the rational design of catalysts for NORR.
PubMed: 38930847
DOI: 10.3390/molecules29122782 -
Materials (Basel, Switzerland) Jun 2024This study investigates the simultaneous decoration of vertically aligned molybdenum disulfide nanostructure (VA-MoS) with Ag nanoparticles (NPs) and nitrogen...
This study investigates the simultaneous decoration of vertically aligned molybdenum disulfide nanostructure (VA-MoS) with Ag nanoparticles (NPs) and nitrogen functionalization. Nitrogen functionalization was achieved through physical vapor deposition (PVD) DC-magnetron sputtering using nitrogen as a reactive gas, aiming to induce p-type behavior in MoS. The utilization of reactive sputtering resulted in the growth of three-dimensional silver structures on the surface of MoS, promoting the formation of silver nanoparticles. A comprehensive characterization was conducted to assess surface modifications and analyze chemical and structural changes. X-ray photoelectron spectroscopy (XPS) showed the presence of silver on the MoS surface. Scanning electron microscopy (SEM) confirmed successful decoration with silver nanoparticles, showing that deposition time affects the size and distribution of the silver on the MoS surface.
PubMed: 38930251
DOI: 10.3390/ma17122882