Publications

Fluorescent Copper Nanoclusters for the Iodide-Enhanced Detection of Hypochlorous Acid

In this work, fluorescent copper nanoclusters (CuNCs) have been fabricated with ascorbic acid (AA) as reductant and polyvinyl pyrolidone (PVP) as scaffold in aqueous solution for the on-site detection of hypochlorous acid (HClO) with high sensitivity and selectivity. The CuNCs showed a specific fluorescence quenching toward HClO compared with other reactive oxygen species and ions that are found widely in the environment. The CuNCs also exhibited a good linear fluorescence quenching effect on HClO with a limit of detection at 55 nM. The mechanism has been investigated and was attributed to the oxidation of reduced Cu on the surface of CuNCs by HClO. Surprisingly, the fluorescence intensity of the probe was more responsive to HClO in the presence of excessive iodide ions (I–), with a lower detection limit of 19 nM. In acidic conditions, iodine (I2) was generated by HClO oxidation and subsequently reacted with Cu atoms on the surface of CuNCs to form cuprous iodide (CuI) precipitation. This resulted in surface defects on the CuNCs, which further significantly reduced the fluorescence intensity of the CuNCs. Under the influence of the reaction mechanism, the order of excessive I– and HClO addition affects the linear range and detection limit of the probe. Because these CuNCs have shown excellent performance as a fluorescent probe, they have been further successfully applied for real-time quantitative detection of HClO in practical samples, and I– can also be used as a “sensitizer” in HClO sensing.

Synthesis, Characterization, and In Vitro Antibacterial Activities of Macromolecules Derived from Bis‐Chalcone

We investigated the antibacterial activity of some new macromolecules such as bis‐pyrazoline, bis‐pyrazole, bis‐pyrimidines prepared from the reaction of bis‐chalcone with thiosemicarbazide/phenyl hydrazine/guanidine hydrochloride/thiourea. All the macromolecules have been characterized by IR, 1 H NMR, 13 C NMR, mass and elemental analyses. The antibacterial activity of these compounds was first tested in vitro by the disc diffusion assay against two Gram‐positive and two Gram‐negative bacteria, and then the minimum inhibitory concentration was determined with the reference to standard drug chloramphenicol. The results showed that pyrazoline derivative showed better antibacterial activity on S. typhimurium and E. coli than the reference drug chloramphenicol.

INCIDENCE, MORTALITY AND CLINICAL OUTCOME OF PATIENTS HOSPITALISED FOR THYROTOXICOSIS WITH AND WITHOUT THYROID STORM IN A SINGLE TERTIARY HOSPITAL

INTRODUCTIONCurrent evidence on the incidence and outcomes of patients with thyroid storm in Malaysia is limited. We determined the incidence of thyrotoxicosis with and without thyroid storm and clinical outcomes among hospitalised patients in a tertiary hospital during an 8-year period. METHODOLOGYA retrospective analysis of clinical characteristics, mortality, hospital length of stay and treatment of thyrotoxic patients with age more than 18 years old in a tertiary hospital with an endocrine service from 2000 to 2018 was performed. Electronic medical records were reviewed to obtain data on predisposing factors, associated conditions and treatment during hospitalisation. RESULTSA total of 249 hospitalised patients with thyrotoxicosis were included. Most were female (73.9%), with a mean age 48.23±0.154 years, and of Malay (26.1%), Chinese (13.7%) and Indian (3.2%) ethnicity. Only 19 (7.7%) were diagnosed with thyroid storm. Graves’ disease (59.8%) was the most common cause of hyperthyroidism, and 15.7% of these hospitalised patient were admitted after one month of being diagnosed. Majority of the patients received carbimazole (81%), with a mean dosage of 20.7 mg OD (±0.77). Precipitating factors included a history of non-compliance to anti-thyroid medication (27.7%) and surgical procedure (10.8%). Mortality and mean length of stay for thyrotoxicosis with or without storm is 6% and5.91 days (±0.356), respectively. The associated conditions that may have increased morbidity were found in many patients: these included atrial ffibrillation (18.9%), acute heart failure (11.6%), acute respiratory failure (10%), acute coronary syndrome (8%), acute renal failure (4.8%), invasive ventilation (4.4%), diabetic ketoacidosis (3.6%), acute ischemic stroke (3.2%), cardiac arrest (2%), acute liver failure (1.8%), ssupraventricular tachycardia (1.2%), cardiogenic shock (1.2%), non-invasive positive pressure ventilation (1.2%), encephalopathy (1.2%), intracranial haemorrhage (1.2%), adrenal insufficiency (0.8%) and pulmonary embolism (0.4%). CONCLUSIONAssociated conditions were found to be frequent in hospitalized patient with thyrotoxicosis with or without thyroid storm. The small percentage of thyroid storm may reflect underreporting or under recognition.

Anion-exchange synthesis of a nanoporous crystalline CoB₂O₄ nanowire array for high-performance water oxidation electrocatalysis in borate solution

Developing nanoporous nanoarray electrocatalysts for efficient water oxidation in environmentally benign media is highly desired but still remains a key challenge. In this communication, we report the fabrication of a nanoporous crystalline CoB₂O₄ nanowire array on Ti mesh (CoB₂O₄/TM) from a Co(OH)F nanowire array on Ti mesh (Co(OH)F/TM) via an anion-exchange reaction. As a three dimensional (3D) catalyst electrode for water oxidation, CoB₂O₄/TM exhibits superior catalytic activity and needs an overpotential of only 446 mV to drive a geometrical catalytic current density of 10 mA cm^-2 in 0.1 M potassium borate (pH = 9.2). Notably, this catalyst also shows strong long-term electrochemical durability with high turnover frequency values of 0.19 and 0.81 mol O₂ per s at overpotentials of 400 and 500 mV, respectively.

Highly efficient and durable water oxidation in a near-neutral carbonate electrolyte electrocatalyzed by a core–shell structured NiO@Ni–Ci nanosheet array

Core–shell structured NiO@Ni–Ci/CC exhibits superior water oxidation activity, requiring 387 mV overpotential to drive 15 mA cm⁻² in 1.0 M K–Ci.

Quinazoline derivatives and hybrids: recent structures with potent bioactivity

Perovskite-based material for sensor applications

CCDC 1044204: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Cu/(Cu(OH) 2 -CuO) core/shell nanorods array: in-situ growth and application as an efficient 3D oxygen evolution anode

CCDC 1545570: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A total Lagrangian elasticity formulation for the nonlinear free vibration of anisotropic beams

CCDC 841160: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Effect of Particle Size on the Photocatalytic Activity and Sensing Properties of CeO2 Nanoparticles

Cerium oxide (CeO2 1) nanoparticles (NP) have been synthesized hydrothermally in the presence of urea and studied the effect of particle size on the chemical sensing and photo-catalytic properties of CeO2. CeO2 1 was described by field emission scanning electron microscopy (FESEM), Energy dispersive spectroscopy (EDS), X-ray powder diffraction (XRD), Raman spectrum, Fourier transform infrared spectroscopy (FTIR), and UV-visible absorption spectrum which divulged that the prepared product is well crystalline cubic phase optically active nanoparticles. SEM images of CeO2 1 illustrated that the synthesized product is composed of cumulative form of highly crytallinity spherical shape nanoparticles with an average diameter of ~ 12 ± 10 nm. Additionally, CeO2 1 was exploited as redox mediator for the development of ethanol chemi-sensor. The fabricated chemical sensor exhibited an excellent performance for electrocatalytic oxidization of ethanol by exhibiting higher sensitivity (1.192 μA.cm-2.M-1) and lower limit of detection (9.7 μM) with the linear dynamic range of 17.0 μM ~ 1.7 M. Moreover, by applying to organic pollutant, CeO2 1 degraded almost 50% of acridine orange in short time. By comparing with 2, CeO2 1 showed lower particle size, lower limit of detection and higher sensitivity toward ethanol sensing and high photo-catalytic activity for degradation of acridine orange. It is concluded that reduction in the particle size enhances the active surface area of the CeO2 which results in increase of chemical sensing and photo-catalytic properties of CeO2.

Copper oxide doped composite nanospheres decorated graphite pencil toward efficient hydrogen evolution electrocatalysis

Synthesis and Characterization of Silver Nanoparticles-Filled Polyethersulfone Membranes for Antibacterial and Anti-Biofouling Application

Analysis of Mixed Micellar Behavior of Promazine Hydrochloride with Surfactants in Aqueous Medium at Different Temperatures and Compositions

Abstract Mixed micellization behavior of an amphiphilic phenothiazine drug promazine hydrochloride (PMZ) in the presence of conventional dodecyltrimethylammonium bromide (DTAB) as well as gemini 1,4-bis( N -dodecyl- N , N -dimethylammonium)butane bromide (12-4-12) cationic surfactants has been studied at four different fixed temperatures and compositions by conductometric technique. The experimental data have been analysed by considering different theoretical models of Clint, Rubingh, Motomura and Rodenas. The cmc and cmc id values indicate mixed micelle formation between the components and strong synergism is observed in the mixed systems. The micellar (actual) mole fractions of surfactants ( χ 1 Rub , χ 1 M , χ 1 Rod and χ 1 id ), calculated on the basis of different theoretical proposed models used in the present study, show greater contribution of surfactants in mixed micelles. Activity coefficients ( f 1 and f 2 ) are always less than unity indicating nonideality in the systems. Thermodynamic parameters are also evaluated and discussed which suggest that at higher temperatures dehydration of hydrophobic part of the drug takes place.

4-(5-Phenyl-3-trifluoromethyl-1<i>H</i>-pyrazol-1-yl)benzenesulfonamide

Significant twists between the aromatic rings are evident in the structure of the title compound, C(16)H(12)F(3)N(3)O(2)S. With reference to the pyrazole plane, the N- and C-bound benzene rings form dihedral angles of 57.12 (11) and 29.75 (11)°, respectively. The dihedral angle between the benzene rings is 52.82 (11)°. The presence of N-H⋯O(sulfonamide) and N-H⋯N(pyrazole) hydrogen bonds lead to supra-molecular tubes along the b-axis direction. These are connected into layers via C-H⋯O inter-actions involving a bifurcated O atom (not involved in the N-H⋯O hydrogen bonding). Layers stack along the a-axis direction.