Chronic pain patients frequently develop and suffer from mental comorbidities such as depressive mood, impaired cognition, and other significant constraints of daily life, which can only ...insufficiently be overcome by medication. The emotional and cognitive components of pain are processed by the medial prefrontal cortex, which comprises the anterior cingulate cortex, the prelimbic, and the infralimbic cortex. All three subregions are significantly affected by chronic pain: magnetic resonance imaging has revealed gray matter loss in all these areas in chronic pain conditions. While the anterior cingulate cortex appears hyperactive, prelimbic, and infralimbic regions show reduced activity. The medial prefrontal cortex receives ascending, nociceptive input, but also exerts important top-down control of pain sensation: its projections are the main cortical input of the periaqueductal gray, which is part of the descending inhibitory pain control system at the spinal level. A multitude of neurotransmitter systems contributes to the fine-tuning of the local circuitry, of which cholinergic and GABAergic signaling are particularly emerging as relevant components of affective pain processing within the prefrontal cortex. Accordingly, factors such as distraction, positive mood, and anticipation of pain relief such as placebo can ameliorate pain by affecting mPFC function, making this cortical area a promising target region for medical as well as psychosocial interventions for pain therapy.
Gold–polyaniline (Au–PANI) nanocomposite was prepared using a simple interfacial polymerization method, performed in an immiscible water/toluene biphasic system using tetrachloroaurate, AuCl4 – as an ...oxidant. The formation of Au nanoparticles (AuNPs) or Au–PANI nanocomposite can be controlled to a certain degree by varying the ratio of initial Au+ and aniline concentrations. Under optimal condition (HAuCl4/aniline ratio is 1:2), green dispersion of Au–PANI nanocomposite is produced in aqueous phase, whose morphology, structure and physicochemical properties are investigated in details. The nanocomposite shows granular morphology with mostly rodlike AuNPs embedded in polymer. It was found that polyaniline in the composite is in the conducting emeraldine salt form, containing high amount of Au (28.85 wt %). Furthermore, the electrical conductivity of the nanocomposite was found to be four-fold higher than that of the polymer itself. In addition, the nanocomposite powder, isolated from the as-prepared aqueous dispersion, can later be easily redispersed in water and further used for various applications. Moreover, the obtained Au-PANI nanocomposite showed excellent electrocatalytic performance toward the electrochemical oxygen reduction reaction (ORR), with high ORR onset potential and good selectivity. This makes it a promising candidate for a new class of Pt-free ORR catalyst.
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The aim of this study is to develop nanosuspension of carvedilol (CRV) by wet media milling. Concentration of polymeric stabilizer (hydroxypropyl cellulose-HPC-SL), milling speed and ...size of milling beads were identified as critical formulation and process parameters and their effect on CRV particle size after 60 min of milling was assessed using a Box-Behnken experimental design. Optimized nanosuspension was solidified using spray drying and freeze drying and subjected to solid state characterization. Low stabilizer concentration (10%), low milling speed (300 rpm) with small milling beads (0.1 mm) were found as optimal milling conditions. Crystal lattice simulation identified potential slip plane within CRV crystals, where fractures are the most likely to occur. Calculated mechanical properties of CRV crystal indicates that low energy stress is sufficient to initiate fracture, if applied in the correct direction, explaining the advantage of using smaller milling beads. Only spray dried nanosuspension redispersed to original nanoparticles, while particle agglomeration during freeze drying prevented sample redispersion. Wet milling and spray drying did not induce polymorphic transition of CRV, while there is indication of polymorphic transition during freeze drying, making spray drying as the preferred solidification method.
The nanodispersed NaTi2(PO4)3/C composite containing 20–25 wt.% of in-situ formed carbon, was synthesized by gel combustion procedure followed by a heat treatment at 650, 700 and 750 °C. The samples ...calcined at 700 and 750 °C displayed crystalline nasicon structure. They were subjected to the investigation of intercalation/deintercalation kinetics in aqueous NaNO3 and LiNO3 solutions, using cyclic voltammetry and galvanostatic charging/discharging measurements. As regards to the effect of electrolyte composition, the reactions were evidenced to be roughly twice faster in sodium nitrate than in lithium nitrate solution. Among the samples treated at 700 and 750 °C, better performance was evidenced for the sample treated at lower temperature. Coulombic capacity in NaNO3 solution at charging rate 1C amounted to ∼70 mAh g−1 and ∼55 mAh g−1 for the sample calcined at 700 and 750 °C, respectively, and displayed surprisingly slight dependence on charging rate up to even 100C.
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•NaTi2(PO4)3/C composite was synthesized by gel-combustion procedure.•Intercalation kinetics was investigated in aqueous nitrate solutions.•Very fast intercalation/deintercalation kinetics was observed.•Ohmic type of current–voltage dependence observed by cyclic voltammetry.•Suprisingly low dependence of capacity on the intercalation rate up to 100C.
The impact of different concentrations of three amino acids (cysteine, histidine and methionine) which are part of the amino acid sequence of rusticyanin on dissolution of pyrite is investigated by ...the application of electrochemical techniques. Cyclic voltammetric studies conducted in the anodic direction from corrosion potential have shown that in the vicinity of corrosion potential, histidine and methionine do not influence dissolution of pyrite independently on their concentrations. On the other hand, cysteine and solutions of these amino acids in the molar ratios Cys:His:Met/1:1:1 and Cys:His:Met/1:2:1 accelerate dissolution at concentrations 10−2 mol L−1 and 10−3 mol L−1. Potentiodynamic polarization measurements showed that methionine does not affect the anodic and cathodic dissolution at all concentrations, while histidine does not affect significantly on the anodic dissolution at all concentrations. Cysteine and solutions of three amino acids in the molar ratio Cys:His:Met/1:1:1 and Cys:His:Met/1:2:1 cause intensive cathodic inhibition and anodic activation at concentrations 10−2 mol L−1 and 10−3 mol L−1 respectively.
•The influence of cysteine, histidine and methionine is investigated.•Individual and mutual impact of these amino acids are considered.•IE is: Cys:His:Met/1:2:1 > Cys:His:Met/1:1:1 > Cys > His > Met.
Chronic neuropathic pain constitutes a serious public health problem, but the disease mechanisms are only partially understood. The involvement of different brain regions like the medial prefrontal ...cortex has already been established, but the comparison of the role of different subregions and layers is still inconclusive. In the current study, we performed patch-clamp recordings followed by anatomical reconstruction of pyramidal cells from different layers of the prelimbic and infralimbic subregions of the medial prefrontal cortex in neuropathic (spared nerve injury, SNI) and control mice. We found that in the prelimbic cortex, layer 2/3 pyramidal cells from SNI mice exhibited increased excitability compared to sham controls, whereas prelimbic layer 5 pyramidal neurons showed reduced excitability. Pyramidal cells in both layer 2/3 and layer 5 of the infralimbic subregion did not change their excitability, but layer 2/3 pyramidal cells displayed increased dendritic length and branching. Our findings support the view that chronic pain is associated with subregion- and layer-specific changes in the medial prefrontal cortex. They therefore provide new insights into the mechanisms underlying the chronification of pain.
The operating characteristics of a commercial monocrystalline and amorphous Si‐solar cell for outdoor and indoor applications with and without the use of the water flow lens (WFL) system are explored ...and reported. The cells are tested in indoor conditions with halogen and tungsten lamps, and additionally, in outdoor sun radiation. Changes in the spectra, investigation of the influence of higher and lower lighting, and indirect cooling of the solar cell are possibilities in the application of the used WFL system. After achieving the highest level of development and improvement for the Si‐solar cell, as well as approaching theoretical maximum efficiency, it is obvious that efficiency gains can be made by better understanding additional light effects. Measurements made on monocrystalline Si‐solar cells revealed that in the “focal point position” where intensity increases (above standard testing conditions STC), independently of indoor or outdoor lighting, huge improvements in ISC and VOC were observed. It was found that the ratios of the short‐circuit current (ISC) and the input light energy (Pinput) are 5.2 and 24.8 for artificial light and 4.9 and 17.6 for outdoor light, without and with the use of the WFL system, respectively. The same trend after applying the WFL system was observed for the amorphous Si cell, except those oscillations were more pronounced at lower light intensities (far lower than STC), as expected. The ratios of ISC and Pinput are in the range of 5.1–5.3 and 10.5–26.5 without and with the use of the WFL system.
This study explores different mechanisms of antimicrobial action by designing hybrid nanomaterials that provide a new approach in the fight against resistant microbes. Here, we present a cheap ...copper–polyaniline (Cu–PANI) nanocomposite material with enhanced antimicrobial properties, prepared by simple in situ polymerization method, when polymer and metal nanoparticles are produced simultaneously. The copper nanoparticles (CuNPs) are uniformly dispersed in the polymer and have a narrow size distribution (d av = 6 nm). We found that CuNPs and PANI act synergistically against three strains, Escherichia coli, Staphylococcus aureus, and Candida albicans, and resulting nanocomposite exhibits higher antimicrobial activity than any component acting alone. Before using the colony counting method to quantify its time and concentration antimicrobial activity, different techniques (UV–visible spectroscopy, transmission electron microscopy, scanning electron microscope, field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrophotometry, and inductively coupled plasma optical emission spectrometry) were used to identify the optical, structural, and chemical aspects of the formed Cu–PANI nanocomposite. The antimicrobial activity of this nanocomposite shows that the microbial growth has been fully inhibited; moreover, some of the tested microbes were killed. Atomic force microscopy revealed dramatic changes in morphology of tested cells due to disruption of their cell wall integrity after incubation with Cu–PANI nanocomposite.
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