Directed diversity-oriented synthesis. Ring-fused 5- to 10-membered rings from a common peptidomimetic 2-pyridone precursor

AbstractA variety of ring-fused 2-pyridone-based central fragments were prepared using a strategy inspired by diversity-oriented synthesis. The produced compounds are diverse, yet focused, analogs of biologically active peptidomimetic 2-pyridones

Thin chemisorbed polyaniline film on cobalt oxide as an electrode for hybrid energy storage devices

Electrical charge storing electrodes and their surface modification are intensively investigated to improve the charge storability indicators in electrochemical energy storage devices. Here, the effects of a thin chemisorbed polyaniline (PANI) film on the charge storage behavior of rod-shaped spinal-type cobalt oxide (Co3O4) nanorods (PANI@Co3O4) are detailed for fabrication of battery–supercapacitor hybrid (BSH) devices. The PANI@Co3O4 showed larger surface area and optimum porosity properties, which contributed to ∼50 % enhanced specific charge than that in the Co3O4. The deconvoluted total charge storage gain showed more contribution to the bulk-diffusion controlled process (battery-type), lower ion transport resistance and Warburg impedance in the PANI@Co3O4 electrode than that in the Co3O4. Two-sets of BSH devices are fabricated using PANI@Co3O4 as a positive electrode and mesoporous carbon (MC) and activated carbon (AC) negative electrodes in an aqueous electrolyte and benchmarked with symmetric supercapacitors fabricated using the two carbons. The PANI@Co3O4//MC device showed nearly two-fold higher specific energy (ES) than that of PANI@Co3O4//AC. Interestingly, AC//AC symmetric supercapacitors showed two-fold higher ES than the MC//MC device. Origin of differences in the charge storage behavior of the two types of devices are systematically analyzed and reported

A 2-pyridone-amide inhibitor targets the glucose metabolism pathway of Chlamydia trachomatis.

UnlabelledIn a screen for compounds that inhibit infectivity of the obligate intracellular pathogen Chlamydia trachomatis, we identified the 2-pyridone amide KSK120. A fluorescent KSK120 analogue was synthesized and observed to be associated with the C. trachomatis surface, suggesting that its target is bacterial. We isolated KSK120-resistant strains and determined that several resistance mutations are in genes that affect the uptake and use of glucose-6-phosphate (G-6P). Consistent with an effect on G-6P metabolism, treatment with KSK120 blocked glycogen accumulation. Interestingly, KSK120 did not affect Escherichia coli or the host cell. Thus, 2-pyridone amides may represent a class of drugs that can specifically inhibit C. trachomatis infection.ImportanceChlamydia trachomatis is a bacterial pathogen of humans that causes a common sexually transmitted disease as well as eye infections. It grows only inside cells of its host organism, within a parasitophorous vacuole termed the inclusion. Little is known, however, about what bacterial components and processes are important for C. trachomatis cellular infectivity. Here, by using a visual screen for compounds that affect bacterial distribution within the chlamydial inclusion, we identified the inhibitor KSK120. As hypothesized, the altered bacterial distribution induced by KSK120 correlated with a block in C. trachomatis infectivity. Our data suggest that the compound targets the glucose-6-phosphate (G-6P) metabolism pathway of C. trachomatis, supporting previous indications that G-6P metabolism is critical for C. trachomatis infectivity. Thus, KSK120 may be a useful tool to study chlamydial glucose metabolism and has the potential to be used in the treatment of C. trachomatis infections

Hydrothermal syntheses of tungsten doped TiO 2 and TiO 2 /WO 3 composite using metal oxide precursors for charge storage applications

Synthesis of advanced functional materials through scalable processing routes using greener approaches is essential for process and product sustainability. In this article, syntheses of nanoparticles of titanium dioxide (TiO₂), tungsten trioxide (WO₃), WO₃-doped titanium dioxide (W-TiO₂) and TiO₂/WO₃ composite at hydrothermal conditions using corresponding metal oxide precursors are described. Electrochemical charge storage capabilities of the above materials are measured using cyclic voltammetry, charge-discharge cycling and electrochemical impedance spectroscopy in aqueous KOH electrolyte. The TiO₂ and the WO₃ nanoparticle showed a specific charge (Q) of ∼12 and ∼36 mA h g⁻¹ at a current density of 2 A g⁻¹ in 6 M KOH, respectively. The Q of TiO₂ increased upon W doping up to 25 mA h g−1 for 5 wt% W-TiO2 and the WO₃/TiO₂ composite showed the highest storage capability (Q ∼40 mA h g⁻¹). Changes in the charge storage capabilities of the doped and composite materials have been correlated to materials properties.Bhupender Pal acknowledges the Research & Innovation Department of Universiti Malaysia Pahang (http://ump.edu.my) for award of Postdoctoral Fellowship. This project is funded under Flagship Strategic Leap 3 of Universiti Malaysia Pahang (Grant Number # RDU 172201)

Modification of Capacitive Charge Storage of TiO2 with Nickel Doping

For practical deployment of supercapacitors characterized by high energy density, power density and long cycle life, they must be realized using low cost and environmentally benign materials. Titanium dioxide (TiO2) is largely abundant in the earth's crust; however, they show inferior supercapacitive electrochemical properties in most electrolytes for practical deployment. In this paper, we show that nickel doped TiO2 (Ni:TiO2) nanowires developed by electrospinning showed five times larger capacitance (∼200 F g−1) than the undoped analogue (∼40 F g−1). Electrochemical measurements show that the Ni:TiO2 nanowires have 100% coulombic efficiency. The electrodes showed no appreciable capacitance degradation for over 5000 cycles. The superior charge storage capability of the Ni:TiO2 could be due to its high electrical conductivity that resulted in five orders of magnitude higher ion diffusion as determined by cyclic voltammetry and electrochemical impedance spectroscopy measurements

Large Scale Synthesis of Binary Composite Nanowires in the Mn2O3-SnO2 System with Improved Charge Storage Capabilities

Large scale production of electrochemical materials in non-conventional morphologies such as nanowires has been a challenging issue. Besides, functional materials for a given application do not often offer all properties required for ideal performance; therefore, a composite is the most sought remedy. In this paper, we report large scale production of a composite nanowire, viz. Mn2O3-SnO2, and their constituent binary nanowires by a large scale electrospinning pilot plant consisting of 100 needles. Electrochemical characterization of thus produced composite nanowires showed nearly threefold increase in the discharge capacity compared to their single component counterparts: Mn2O3-SnO2 ∼53 mA h g−1 (specific capacitance, CS ∼384 F g−1); Mn2O3 ∼18 mA h g−1 (CS ∼164 F g−1); and SnO2 ∼14 mA h g−1 (CS ∼128 F g−1) at 1 A g−1 in 6 M KOH. The EIS studies showed that the characteristic resistances and time of the composite electrode are appreciably lower than their constituents. Owing to the scalability of the synthesis processes and promising capacitive properties achieved would lead the composite material as a competitive low-cost and high-performance supercapacitor electrode

Transformation of supercapacitive charge storage behaviour in a multi elemental spinel CuMn2O4 nanofibers with alkaline and neutral electrolytes

Electrode material has been cited as one of the most important determining factors in classifying an energy storage system’s charge storage mechanism, i.e., as battery-type or supercapacitive-type. In this paper, we show that along with the electrode material, the electrolyte also plays a role in determining the charge storage behaviour of the system. For the purpose of our research, we chose multi-elemental spinal type CuMn2O4 metal oxide nanofibers to prove the hypothesis. The material is synthesized as nanofibers of diameter ~ 120 to 150 nm in large scales by a pilot scale electrospinning set up. It was then tested in three different electrolytes (1 M KOH, 1 M Na2SO4 and 1 M Li2SO4), two of which are neutral and the third is alkaline (KOH). The cyclic voltammograms and the galvanostatic charge–discharge of the electrode material in a three-electrode system measurement showed that it exhibit different charge storage mechanism in different electrolyte solutions. For the neutral electrolytes, a capacitive behaviour was observed whereas a battery-type behaviour was seen for the alkaline electrolyte. This leads us to conclude that the charge storage mechanism, along with the active material, also depends on the electrolyte used

Cerebellar and basal ganglia structural connections in humans: Effect of aging and relation with memory and learning

IntroductionThe cerebellum and basal ganglia were initially considered anatomically distinct regions, each connected via thalamic relays which project to the same cerebral cortical targets, such as the motor cortex. In the last two decades, transneuronal viral transport studies in non-human primates showed bidirectional connections between the cerebellum and basal ganglia at the subcortical level, without involving the cerebral cortical motor areas. These findings have significant implications for our understanding of neurodevelopmental and neurodegenerative diseases. While these subcortical connections were established in smaller studies on humans, their evolution with natural aging is less understood.MethodsIn this study, we validated and expanded the previous findings of the structural connectivity within the cerebellum-basal ganglia subcortical network, in a larger dataset of 64 subjects, across different age ranges. Tractography and fixel-based analysis were performed on the 3 T diffusion-weighted dataset using Mrtrix3 software, considering fiber density and cross-section as indicators of axonal integrity. Tractography of the well-established cerebello-thalamo-cortical tract was conducted as a control. We tested the relationship between the structural white matter integrity of these connections with aging and with the performance in different domains of Addenbrooke’s Cognitive Examination.ResultsTractography analysis isolated connections from the dentate nucleus to the contralateral putamen via the thalamus, and reciprocal tracts from the subthalamic nucleus to the contralateral cerebellar cortex via the pontine nuclei. Control tracts of cerebello-thalamo-cortical tracts were also isolated, including associative cerebello-prefrontal tracts. A negative linear relationship was found between the fiber density of both the ascending and descending cerebellum-basal ganglia tracts and age. Considering the cognitive assessments, the fiber density values of cerebello-thalamo-putaminal tracts correlated with the registration/learning domain scores. In addition, the fiber density values of cerebello-frontal and subthalamo-cerebellar (Crus II) tracts correlated with the cognitive assessment scores from the memory domain.ConclusionWe validated the structural connectivity within the cerebellum-basal ganglia reciprocal network, in a larger dataset of human subjects, across wider age range. The structural features of the subcortical cerebello-basal ganglia tracts in human subjects display age-related neurodegeneration. Individual morphological variability of cerebellar tracts to the striatum and prefrontal cortex was associated with different cognitive functions, suggesting a functional contribution of cerebellar tracts to cognitive decline with aging. This study offers new perspectives to consider the functional role of these pathways in motor learning and the pathophysiology of movement disorders involving the cerebellum and striatum

Electrospinning research and products: The road and the way forward

Electrospinning is one of the most accessed nanofabrication techniques during the last three decades, attributed to its viability for the mass production of continuous nanofibers with superior properties from a variety of polymers and polymeric composites. Large investments from various sectors have pushed the development of electrospinning industrial setups capable of producing nanofibers in millions of kilograms per year for several practical applications. Herein, the lessons learned over three decades of research, innovations, and designs on electrospinning products are discussed in detail. The historical developments, engineering, and future opportunities of electrospun nanofibers (ESNFs) are critically addressed. The laboratory-to-industry transition gaps for electrospinning technology and ESNFs products, the potential of electrospun nanostructured materials for various applications, and academia-industry comparison are comprehensively analyzed. The current challenges and future trends regarding the use of this technology to fabricate promising nano/macro-products are critically demonstrated. We show that future research on electrospinning should focus on theoretical and technological developments to achieve better maneuverability during large-scale fiber formation, redesigning the electrospinning process around decarbonizing the materials processing to align with the sustainability agenda and the integration of electrospinning technology with the tools of intelligent manufacturing and IR 4.0

Pseudocapacitive charge storage in thin nanobelts

This article reports that extremely thin nanobelts (thickness ~ 10 nm) exhibit pseudocapacitive (PC) charge storage in the asymmetric supercapacitor (ASC) configuration, while show battery-type charge storage in their single electrodes. Two types of nanobelts, viz. NiO–Co3O4 hybrid and spinal-type NiCo2O4, developed by electrospinning technique are used in this work. The charge storage behaviour of the nanobelts is benchmarked against their binary metal oxide nanowires, i.e., NiO and Co3O4, as well as a hybrid of similar chemistry, CuO–Co3O4. The nanobelts have thickness of ~ 10 nm and width ~ 200 nm, whereas the nanowires have diameter of ~ 100 nm. Clear differences in charge storage behaviours are observed in NiO–Co3O4 hybrid nanobelts based ASCs compared to those fabricated using the other materials—the former showed capacitive behaviour whereas the others revealed battery-type discharge behaviour. Origin of pseudocapacitance in nanobelts based ASCs is shown to arise from their nanobelts morphology with thickness less than typical electron diffusion lengths (~ 20 nm). Among all the five type of devices fabricated, the NiO–Co3O4 hybrid ASCs exhibited the highest specific energy, specific power and cycling stability