Chronic pain is a condition in which pain progresses from an acute to chronic state and persists beyond the healing process. Chronic pain impairs function and decreases patients' quality of life. In ...recent years, efforts have been made to deepen our understanding of chronic pain and to develop better treatments to alleviate chronic pain. In this review, we summarize the results of previous studies, focusing on the mechanisms underlying chronic pain development and the identification of neural areas related to chronic pain. We review the association between chronic pain and negative affective states. Further, we describe the structural and functional changes in brain structures that accompany the chronification of pain and discuss various neurotransmitter families involved. Our review aims to provide guidance for the development of future therapeutic approaches that could be used in the management of chronic pain.
Recently, clinicians have been using repetitive transcranial magnetic stimulation (rTMS) for treating various pain conditions. This systematic narrative review aimed to examine the use and efficacy ...of rTMS for controlling various pain conditions. A PubMed search was conducted for articles that were published until June 7, 2019 and used rTMS for pain alleviation. The key search phrase for identifying potentially relevant articles was (repetitive transcranial magnetic stimulation AND pain). The following inclusion criteria were applied for article selection: (1) patients with pain, (2) rTMS was applied for pain management, and (3) follow-up evaluations were performed after rTMS stimulation to assess the reduction in pain. Review articles were excluded. Overall, 1,030 potentially relevant articles were identified. After reading the titles and abstracts and assessing eligibility based on the full-text articles, 106 publications were finally included in our analysis. Overall, our findings suggested that rTMS is beneficial for treating neuropathic pain of various origins, such as central pain, pain from peripheral nerve disorders, fibromyalgia, and migraine. Although data on the use of rTMS for orofacial pain, including trigeminal neuralgia, phantom pain, low back pain, myofascial pain syndrome, pelvic pain, and complex regional pain syndrome, were promising, there was insufficient evidence to determine the efficacy of rTMS for treating these conditions. Therefore, further studies are needed to validate the effects of rTMS on pain relief in these conditions. Overall, this review will help guide clinicians in making informed decisions regarding whether rTMS is an appropriate option for managing various pain conditions.
Display omitted
•NaOH-modified activated carbon fiber removes to heavy metals, cost-effectively.•The NaOH modification induced abundant oxygen functional groups in micropore.•Heavy metals adsorbed by ...a polar oxygen functional groups and pore filling mechanism.
This manuscript describes an efficient and cost-effective method to remove heavy metals of Hg and Cd in aqueous solutions via adsorption on activated carbon fibers after modification with NaOH solution (NaACF). The Hg and Cd metals in the aqueous solution exist as Hg(OH)2 and Cd2+ in the experimental condition of pH 6–8. Surface characterization of the NaACF reveals uniform and narrower micropores with an increase in oxygen functional groups of phenol and lactone compared with the original ACF (pACF). The NaACF demonstrates a superior adsorption rate to both aqueous samples of heavy metal compounds. The granular activated carbon (GAC) with diverse pore structures consisting of micropores, mesopores, and macropores adsorbed the heavy metals at a relatively slow rate. The adsorption mechanisms of the heavy metals into NaACF pores are proposed as pore-filling with non-ionic Hg(OH)2 and electron sharing of oxygens in phenolic, lactone, and carboxylic acid groups with ionic Cd2+. The results from continuous feeding are also reported for the sample blend of 10 wt% NaACF and 90 wt% GAC in increasing the cost performance ratio.
•The hydration kinetics of MgO-activated blast furnace slag is studied.•The main hydration products include a C-A-S-H type gel, ettringite, monosulfate, hydrotalcite, and TAH.•Higher MgO increases ...the degree of reaction of slag.•Higher MgO increases the solid binder volume, and the strength of the samples.
Hydration kinetics and products of MgO-activated slag are investigated by employing multiple analytical characterization techniques and thermodynamic modelling. The main hydration products of this cement are a calcium-aluminosilicate hydrate type gel, ettringite, monosulfate, hydrotalcite, brucite, and a third aluminate hydrate, while the extent of reaction and formation of reaction products significantly varied by MgO dosages. Higher dosage of MgO increased the degree of reaction of slag, and led to a higher population of Al in the octahedral region, which can be attributed to greater competition for Al required for the formation of hydrotalcite. The experimental and simulated volume of the solid binder increased as the MgO dosage increased, showing a good correlation with the strength increase of the samples with higher MgO dosage.
Si-based composites wrapped in multiple graphene shells were successfully fabricated as binder-free anodes for Li-ion batteries (LIBs). Reduced graphene oxide (rGO) and Si nanoparticles were prepared ...as spherical composite structures using a facile spray-drying process. The microspheres were homogeneously incorporated into a 3D porous graphene aerogel (GA) structure using an aerogel synthesis process. The inner rGO shell surrounding the Si nanoparticles promoted an effective electron transfer from the surface of the Si nanoparticles to electrolytes and suppressed the continuous formation of an unstable solid–electrolyte interface layer. Moreover, the 3D, porous GA framework, which demonstrated high electrical conductivity and mechanical stability, promoted the homogeneous dispersion of the Si nanoparticles, an effective and fast Li+ ion diffusion, and the suppression of volume expansion during lithiation. The rGO/Si/GA composite anode constructed by multiple graphene shells had an extremely high initial discharge capacity (1217 mAh g−1), excellent cyclic stability (462 mAh g−1 at 1.0 C after 200 cycles), and superior rate capability (819 mAh g−1 at 10 C) owing to its multilayered structure. We expect that our simple and scalable approach for fabricating Si-based anodes wrapped in multiple graphene shells can contribute to the development of high-performance LIBs for use in electric vehicles.
Display omitted
•Graphene/Si microspheres are prepared using a facile spray-drying process.•The microspheres are incorporated into a 3D porous graphene aerogel (GA) structure.•The binder-free graphene/Si/GA anode has an excellent electrochemical performance.
There is an urgent need to develop improved anode materials for lithium-ion batteries (LIBs). Herein, we report the synthesis of a graphene quantum dots (GQDs)-coated hierarchical nanoflake-based CuO ...microspheres (H–CuO) composite on Cu foam via a one-pot hydrothermal technique for use as a binder-free anode for LIBs. The carboxyl-functionalized GQD coating on H–CuO not only results in lower charge-transfer resistance and enhanced electrical conductivity but also prevents the dissolution and agglomeration of the electrode. The GQDs/H–CuO composite anode exhibits a reversible capacity as high as 609 mAh g−1 (pristine H–CuO: 61 mAh g−1) after 200 cycles at 0.2 A g−1. It also shows long-term cycling stability, exhibiting a capacity retention rate of 79.4% after 1000 cycles (pristine H–CuO: 0.7%) at a high current density (2 A g−1) and improved initial coulombic efficiency at 88.2% (pristine H–CuO: 75.2%). The superior electrochemical properties of the GQDs/H–CuO composite anode are attributable to the graphene networks, which help maintain a high specific surface area and effectively protect the anodic active material from forming an unstable solid electrolyte interface layer. The proposed strategy for fabricating the GQD-coated metal oxide microsphere-based anode should contribute to the development of next-generation LIBs with improved electrochemical performance.
Display omitted
•Graphene quantum dots (GQDs)/hierarchical CuO microspheres (H-CuO) composite is fabricated via hydrothermal technique.•The GQDs/H–CuO composite is used as a binder-free anode for lithium-ion batteries.•The GQDs/H–CuO composite anode exhibits high reversible capacity.•The GQDs/H–CuO composite anode exhibits excellent long-term cycling stability.
Hexagonal boron nitride (h-BN)/epoxy composites with high through-plane thermal conductivity were successfully fabricated using core-shell h-BN/epoxy (e-BN) microspheres which were synthesized using ...a simple one-pot emulsion polymerization process in an eco-friendly aqueous medium. e-BN microspheres covered with self-assembled h-BN flakes (1 μm lateral size) on the surface of the epoxy microspheres facilitated the effective alignment and distribution of the flakes in the epoxy matrix. The e-BN/BN/epoxy composites fabricated by mixing the e-BN microspheres with the h-BN flakes (17 μm lateral size) exhibited far higher through-plane thermal conductivity than the BN/epoxy composites (without e-BN microspheres) with the same h-BN flake content. In particular, the e-BN/BN/epoxy composite with 50 wt% (33 vol%) h-BN flakes exhibited excellent through-plane thermal conductivity of 4.27 W/mK, which was approximately 3.7 times that of the BN/epoxy composite (1.17 W/mK), owing to a more random or isotropic orientation of the h-BN flakes in the e-BN/BN/epoxy composite. The experimentally measured thermal conductivities were well matched to those obtained from micromechanical estimations using the modified Mori-Tanaka method. We expect that this eco-friendly and scalable fabrication process of e-BN microspheres and e-BN/BN/epoxy composites could provide an innovative strategy for manufacturing electrically insulating polymer composites with high through-plane thermal conductivity.
Display omitted
•Core-shell BN/epoxy (e-BN) microspheres were fabricated.•BN/epoxy composites were fabricated by mixing e-BN microspheres with h-BN flakes.•Insulating BN/epoxy composites showed excellent through-plane thermal conductivity.•Thermal conductivity data were well matched to micromechanical estimation data.
Site-selective modification of oligonucleotides serves as an indispensable tool in many fields of research including research of fundamental biological processes, biotechnology, and nanotechnology. ...Here we report chemo- and regioselective modification of oligonucleotides based on rhodium(I)-carbene catalysis in a programmable fashion. Extensive screening identifies a rhodium(I)-catalyst that displays robust chemoselectivity toward base-unpaired guanosines in single and double-strand oligonucleotides with structurally complex secondary structures. Moreover, high regioselectivity among multiple guanosines in a substrate is achieved by introducing guanosine-bulge loops in a duplex. This approach allows the introduction of multiple unique functional handles in an iterative fashion, the utility of which is exemplified in DNA-protein cross-linking in cell lysates.
Crosstalk between liver and skeletal muscle is vital for glucose homeostasis. Hepatokines, liver-derived proteins that play an important role in regulating muscle metabolism, are important to this ...communication. Here we identify apolipoprotein J (ApoJ) as a novel hepatokine targeting muscle glucose metabolism and insulin sensitivity through a low-density lipoprotein receptor-related protein-2 (LRP2)-dependent mechanism, coupled with the insulin receptor (IR) signaling cascade. In muscle, LRP2 is necessary for insulin-dependent IR internalization, an initial trigger for insulin signaling, that is crucial in regulating downstream signaling and glucose uptake. Of physiologic significance, deletion of hepatic ApoJ or muscle LRP2 causes insulin resistance and glucose intolerance. In patients with polycystic ovary syndrome and insulin resistance, pioglitazone-induced improvement of insulin action is associated with an increase in muscle ApoJ and LRP2 expression. Thus, the ApoJ-LRP2 axis is a novel endocrine circuit that is central to the maintenance of normal glucose homeostasis and insulin sensitivity.
The electrochemical performance of sulfur-doped carbon nanotubes (S-CNTs) was investigated to confirm the S-doping effects and the possibility of their application as conducting agents in ...supercapacitor electrodes. S-CNTs were successfully synthesized via chemical vapor deposition using dimethyl disulfide as the carbon source. They were purified to obtain purified S-CNTs (P–S-CNTs) with diameters 30–50 nm and S content of 0.65 at%. The doped S atoms were removed partially from the P–S-CNTs by heat treatment in H2 atmosphere (De-P-S-CNTs). To compare the electrochemical performances of various conducting materials for supercapacitor electrodes, commercial activated carbon (MSP20) was used as the active material and commercial conducting agent (Super-P), commercial multi-walled CNTs (MWCNTs), De-P-S-CNTs, and P–S-CNTs were used as the conducting agents. The electrode with P–S-CNTs exhibited the highest specific capacitance at a high discharge current density of 100 mA cm−2 (120.2 F g−1) and the lowest charge-transfer resistance (6.19 Ω) that are significantly superior to those of Super-P (83.9 F g−1 and 15.16 Ω), MWCNTs (87.8 F g−1 and 17.02 Ω), and De-P-S-CNTs (90.1 F g−1 and 22.33 Ω). The superior electrochemical performance of P–S-CNTs can be attributed to the excellent electrical conductivity and pseudocapacitive contribution of the S-doping effect.
Display omitted
•Sulfur-doped carbon nanotubes (S-CNTs) are synthesized by chemical vapor deposition.•Purified S-CNTs can be used as conducting agents in supercapacitor electrodes.•Electrochemical performance of CNTs is enhanced by sulfur (S) doping.•Conductivity and pseudocapacitive contribution of S doping improve electrochemical performance.
PDF
