Fabrication of TiO2-Nanotube-Array-Based Supercapacitors

In this work, a simple and cost-effective electrochemical anodization technique was adopted to rapidly grow TiO₂ nanotube arrays on a Ti current collector and to utilize the synthesized materials as potential electrodes for supercapacitors. To accelerate the growth of the TiO₂ nanotube arrays, lactic acid was used as an electrolyte additive. The as-prepared TiO₂ nanotube arrays with a high aspect ratio were strongly adhered to the Ti substrate. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results confirmed that the TiO₂ nanotube arrays were crystallized in the anatase phase. TEM images confirmed the nanotublar-like morphology of the TiO₂ nanotubes, which had a tube length and a diameter of ~16 and ~80 nm, respectively. The electrochemical performance of the TiO₂ nanotube array electrodes was evaluated using the cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge (GCD) measurements. Excellent electrochemical response was observed for the electrodes based on the TiO₂ nanotube arrays, as the cells delivered a high specific capacitance of 5.12 mF/cm² at a scan rate of 100 mV/s and a current density of 100 μA/cm². The initial capacity was maintained for more than 250 cycles. Further, a remarkable rate capability response was observed, as the cell retained 88% of the initial areal capacitance when the scan rate was increased from 10 to 500 mV/s. The results suggest the suitability of TiO₂ nanotube arrays as electrode materials for commercial supercapacitor applications

Structural Transition-Induced Raman Enhancement in Bioinspired Diphenylalanine Peptide Nanotubes

Semiconducting materials are increasingly proposed as alternatives to noble metal nanomaterials to enhance Raman scattering. We demonstrate that bioinspired semiconducting diphenylalanine peptide nanotubes annealed through a reported structural transition can support Raman detection of 10-7 M concentrations for a range of molecules including mononucleotides. The enhancement is attributed to the introduction of electronic states below the conduction band that facilitate charge transfer to the analyte molecule. These results show that organic semiconductor-based materials can serve as platforms for enhanced Raman scattering for chemical sensing. As the sensor is metal-free, the enhancement is achieved without the introduction of electromagnetic surface-enhanced Raman spectroscopy.Science Foundation IrelandUCD School of PhysicsSustainable Energy Authority of Ireland (SEAI

Multiple sclerosis following bariatric surgery: A report of five cases

Multiple sclerosis (MS) is a debilitating chronic inflammatory demyelinating disease that affects the central nervous system. The underlying cause of multiple sclerosis is unknown, yet there are various predisposing factors. Currently, bariatric surgery is an increasingly common solution for obesity. It has been reported that bariatric procedures result in miscellaneous neurological complications. To the best of our knowledge, this is the first case series to report the occurrence of MS following bariatric surgery. Here we report the cases of five patients who were recruited for inclusion following neurological examination, complete cerebrospinal fluid (CSF) study, enhanced cranial as well as spinal cord magnetic resonance (MR) images. Diagnosis of multiple sclerosis was made based on McDonalds criteria (2010). All cases were diagnosed with relapsing-remitting form of multiple sclerosis (RRMS) after various types of bariatric surgeries

Relationship Between Glycated Haemoglobin and Carotid Atherosclerotic Disease Among Patients with Acute Ischaemic Stroke

Objectives: This study aimed to determine the relationship between glycaemic control and carotid atherosclerotic disease among patients with acute ischaemic stroke (AIS). Methods: This retrospective cross-sectional study took place in the Neurology Department of King Fahad Hospital of University, Khobar, Saudi Arabia, from April to October 2017. Data were collected from the medical records of 244 patients with a diagnosis of AIS confirmed by computed tomography. Doppler ultrasounds of the carotid artery were performed to determine the presence of increased carotid intima media thickness (CIMT) and plaques. Results: Significantly higher mean glycated haemoglobin (HbA1c) levels were noted in cases with high CIMT values (P = 0.002), but not in cases with carotid plaques (P = 0.360). In addition, there was a significant association between diabetes mellitus (DM) and high CIMT (P = 0.045), but not with carotid plaques (P = 0.075). Finally, while dyslipidaemia and age were independently correlated with high CIMT values (P = 0.034 and 0.050 each). Conclusion: High HbA1c levels were associated with high CIMT values, but not with carotid plaques. Therefore, HbA1c levels may be useful as an indirect marker of the initial stages of carotid artery atherosclerosis. Keywords: Glycated Hemoglobin A1c; Diabetes Mellitus; Carotid Intima-Media Thickness; Atherosclerotic Plaque; Stroke

The association between linagliptin and acute pancreatitis: A review

BackgroundLinagliptin is a Dipeptidyl Peptidase inhibitor (DPP-4i) with rare hypoglycaemic episodes and no need for renal adjustment. However, acute pancreatic is a major concern.AimsThe current review aimed to assess the relationship between linagliptin and acute pancreatitis.Methods A systematic electronic search was conducted in PubMed, MEDLINE, and the first hundred articles of Google Scholar for relevant articles. All human studies published during the period from 2006 to October 2019 were eligible. Studies on animals, experimental studies, and reviews were excluded. The search terms linagliptin, acute pancreatitis, chronic pancreatitis, and DPP-4i with protean AND or OR were used One hundred and thirty-two articles were retrieved and only six met the inclusion and exclusion criteria. The author's name, country of origin, date of publication, type of study, number of patients, and the duration were reported.Results There were 132 studies (thirty-two in Pub Med and MEDLINE and the first hundred articles in Google Scholar), out of fourteen full texts reviewed, only six studies were eligible. Three were meta-analyses (showed no association of linagliptin with acute pancreatitis, a pooled analysis of 22 randomized controlled trials supported the above observation, while a recent randomized controlled trial concluded acute pancreatitis in 0.3 per cent in linagliptin arm vs. 0.1 per cent placebo of which 2/9 were fatal. The last study was a case report at a high risk of acute pancreatitis due to multiple gallstones and diuretics use.ConclusionAcute pancreatitis was not higher among linagliptin users. Physicians need to take the benefits of this weight and cardiovascular risk-neutral drug with no need for renal adjustment

Bio-Inspired Facile Synthesis of Graphene-Based Nanocomposites: Elucidation of Antimicrobial and Biofilm Inhibitory Potential against Foodborne Pathogenic Bacteria

Herein, a new and simple biogenic method for the preparation of gold nanoparticles (AuNPs) and their reduced graphene oxide based nanocomposites (Au-RGO) by using microwave irradiation method for antimicrobial and biofilm inhibition against foodborne pathogenic bacteria was reported. X-ray diffraction (XRD), Raman, and transmission electron microscopy (TEM) analyses confirmed that the AuNPs with face centered cubic (FCC) structure were indeed anchored onto the RGO sheets. Ultraviolet-Vis (UV-VIS) spectrum showed a shifting and broadening of absorption peaks of AuNPs when attached on the surface of RGO sheets. The effect of sub-inhibitory concentrations of Au-RGO nanocomposites on biofilm formation in five foodborne pathogens was assessed. Au-RGO nanocomposites reduced the formation of biofilm by 75%, 78%, 68%, 80% and 79% in L. monocytogenes, MRSA, E. coli, S. marcescens and P. aeruginosa, respectively. Exopolysaccharides (EPS), a vital component of the biofilm was also inhibited significantly and pre-formed mature biofilms were also reduced considerably. Further, this study demonstrated that the reactive oxygen species (ROS) generation induced in bacterial cells as a result of Au-RGO treatment could be the plausible mechanism for biofilm inhibitory action. The tested concentrations were found non-toxic to human embryonic kidney cell lines (HEK-293). The investigation highlights the broad-spectrum biofilm inhibitory properties of Au-RGO nanocomposites that could be exploited in the food industry to prevent biofilm-based food contamination

Enhancement of the Supercapacitive Performance of Cobalt-tin-cyanate Layered Structures through Conversion from 2D Materials to 1D Nanofibers

Rational design of the micro-nanomorphology is highly desired for metal hydroxides to achieve overall high-performance electrodes for supercapacitor and energy storage applications. Here, in the current study, we have succeeded in controlling the morphology of Sn/Co nanolayered structures to obtain plate and nanofibrous morphologies. Additionally, the plate nanostructures could be transformed to obtain plate-nanofibrous morphologies. In this trend, dual anions such as cyanate and nitrate are applied to intercalate among the nanolayers of cobalt-tin and act as building blocks or pillars, producing a series of nanolayered structures. By repulsion forces among the intercalated anions, the nanolayers of Sn/Co are curled and converted to nanofibers. This conversion was confirmed by scanning electron microscopy. In addition, the intercalation reactions and nanolayered structures were indicated by X-ray diffraction, thermal analyses and Fourier-transform infrared spectroscopy. The electrochemical supercapacitive behavior of the different nanostructures of Sn/Co HDS and Sn/Co LDH, such as plate, Plate-nanofiber and nanofibrous morphology has been investigated in three assembly electrode system. The results suggested that the nanofiber morphology of Sn/Co LDH exhibited better specific capacitance performance than the other two morphologies. The enhanced specific capacitance (658 Fg−1) and excellent cyclic stability (89%) of the nanofibers of the Sn/Co LDH could be attributed to the synergistic effects between the electric double layer capacitive character of the tin and the pseudocapacitance nature of the cobalt

Designing Magnetic Layered Double Hydroxides and Two-Dimensional Magnetic Nano-Nets of Cobalt Ferrite through a Novel Approach

The present study has a dual aim of supporting magnetic nanoparticles over the nanolayers of LDHs and designing two-dimensional magnetic nano-nets of cobalt ferrite. In this trend, nanoparticles of CoFe2O4 were prepared and supported by Co-Fe LDH through urea hydrolysis. The nanolayered structures of Co-Fe LDH were confirmed by X-ray diffraction, energy-dispersive X-ray spectrometry, FT-IR spectra, thermal analyses, and transmission electron microscopy. In addition, they indicated that 13.2% CoFe2O4 were supported over Co-Fe LDH. Transformation of the nanolayered structures of Co-Fe LDH to nano-nets was achieved by the catalytic effect of the supported CoFe2O4 nanoparticles through solvent thermal technique. X-ray diffraction patterns and transmission electron microscopy images confirmed the transformation of the supported Co-Fe LDH to nano-nets of cobalt ferrite. In order to indicate the effect of the LDH for designing the nano-nets, nanoparticles of cobalt ferrite were prepared by the same technique without LDH. The magnetic behavior of the nano-nets and the supported Co-Fe LDH were measured and compared with the nanoparticles through vibrating sample magnetometer technique. The magnetic parameters indicated that the prepared nano-nets have ferromagnetic behavior and high coercivity. However, the prepared nanoparticles revealed a superparamagnetic state and low coercivity. The experimental results concluded that the incorporation of nanoparticles with nanowires into nano-net structures has been found to be an efficient way to improve their magnetic properties and prevent their agglomerations. Finally, layered double hydroxides are an important source for constructing magnetic nanolayered structures and nano-nets

Growth of Defect-Induced Carbon Nanotubes for Low-Temperature Fruit Monitoring Sensor

Herein, a carbon nanotubes-based sensor has been grown for the purpose of ethylene detection. The prepared CNTs had a crystalline structure with a smooth surface of 11.0 nm in diameter and 10.0 µm in length. The low-intensity graphite peak (G-band) as compared to the peak of the defect (D-band) characterizes the defects in the CNTs. An MWNTs-gas sensor was fabricated for monitoring the ethylene gas. The highest response was recorded at a low operating temperature of 30 °C. The sensor was also examined at 300 ppb up to 10 ppm and it showed a response of 2% up to 28%. The sensor response and recovery time constants were varied from 60 to 300 s, depending on the gas concentration. The results that were obtained for the synthetic ethylene gas were also compared with the real measurements for banana ripening. The results confirmed that the sensor is appropriate for the monitoring of fruit ripening