Azhar Abdul Rahman

Sb-C Bond Cleavage Reaction on a Triruthenium Cluster and the Formation of a Bridging Phenylacyl Unit

Syntheses and single crystal X-ray structures of an open triruthenium acyl carbonyl cluster [(C6H5)2SbRu3(COC6H5)(CO)10] (1) and a simple triruthenium Ru3(CO)9[(C6H5)2PCH2P(C6H5)2]Sb(C6H5)3(2) are reported. Formation of compound (1) at room temperature from [Ru3(CO)12] and [Sb(C6H5)3] is unique, a similar reaction with Ru3(CO)10[(C6H5)2PCH2P(C6H5)2] under identical conditions results in compound (2), with Sb(C6H5)3 occupying an equatorial site. IR, 1H, 13C NMR spectra of the compounds are reported. The X-ray crystal structure of (1) consist of 2 crystallography distinct molecules and shows Ru–Sb distances in the range: 2.6361(6)–2.6273(7) Å and Ru–Ru distances in the range: 2.8236(7)–2.9855(7) Å. Ru–O distances in the bridging carbonyl are: 2.137(4), 2.158(4) Å. The Sb–Ru–Ru angles in the two molecules of the asymmetric unit are in the range of 73.78(2)–77.52° indicating the puckered nature. Compound (2) has bond parameters comparable to those of Ru3(CO)10[(C6H5)2PCH2P(C6H5)2]. The present study shows for the first time that the cleaving of Sb–C bond at room temperature is possible under non-ionic conditions, though there have been many instances of P–C and As–C bond cleavages reported previously.

Antinociceptive and antiedematogenic activities of andrographolide isolated from Andrographis paniculata in animal models.

The current study was performed to evaluate the antinociceptive and antiedematogenic properties of andrographolide isolated from the leaves of Andrographis paniculata using two animal models. Antinociceptive activity was evaluated using the acetic acid— induced writhing and the hot-plate tests, while antiedematogenic activity was measured using the carrageenan-induced paw edema test. Subcutaneous (s.c.) administration of andrographolide (10, 25, and 50 mg/kg) did not affect the motor coordination of the experimental animals but produced significant (p < .05) antinociceptive activity when assessed using both tests. However, 2 mg/kg naloxone failed to affect the 25 mg/kg andrographolide activity in both tests, indicating that the activity was modulated via nonopioid mechanisms. Furthermore, andrographolide showed significant (p < .05) antiedematogenic activity. In conclusion, the results obtained suggest that andrographolide has antinociceptive and antiedematogenic activities; it may be useful for treating pain and inflammation once human studies are conducted.

Structural and Optical Properties of Lead-Boro-Tellurrite Glasses Induced by Gamma-Ray

Spectrophotometric studies of lead borotellurite glasses were carried out before and after gamma irradiation exposure. The increasing peak on the TeO4 bi-pyramidal arrangement and TeO3+1 (or distorted TeO4) is due to augmentation of irradiation dose which is attributed to an increase in degree of disorder of the amorphous phase. The structures of lead tellurate contain Pb3TeO6 consisting of TeO3 trigonal pyramid connected by PbO4 tetragonal forming a three-dimensional network. The decrease of glass rigidity is due to irradiation process which is supported by the XRD diffractograms results. The decreasing values of absorption edge indicate that red shift effect occur after irradiation processes. A shift in the optical absorption edge attributed to an increase of the conjugation length. The values of optical band gap, Eopt were calculated and found to be dependent on the glass composition and radiation exposure. Generally, an increase and decrease in Urbach’s energy can be considered as being due to an increase in defects within glass network.

Determination of radioactive elements and heavy metals in sediments and soil from domestic water sources in northern peninsular Malaysia.

Soil serves as a major reservoir for contaminants as it posseses an ability to bind various chemicals together. To safeguard the members of the public from an unwanted exposure, studies were conducted on the sediments and soil from water bodies that form the major sources of domestic water supply in northern peninsular Malaysia for their trace element concentration levels. Neutron Activation Analysis, using Nigeria Research Reactor-1 (NIRR-1) located at the Centre for Energy Research and Training, Zaria, Nigeria was employed as the analytical tool. The elements identified in major quantities include Na, K, and Fe while As, Br, Cr, U, Th, Eu, Cs, Co, La, Sm, Yb, Sc, Zn, Rb, Ba, Lu, Hf, Ta, and Sb were also identified in trace quantities. Gamma spectroscopy was also employed to analyze some soil samples from the same area. The results indicated safe levels in terms of the radium equivalent activity, external hazard index as well as the mean external exposure dose rates from the soil. The overall screening of the domestic water sources with relatively high heavy metals concentration values in sediments and high activity concentration values in soil is strongly recommended as their accumulation overtime as a consequence of leaching into the water may be of health concern to the members of the public.

A study of particulate matter concentration released during laser paint removal process on car coated substrate

Normalization mass (N) of particulate matter (PM) per one laser shot and 1.0 cm2 released during the laser irradiation were measured on three different types of car coated substrate samples A, B and C by using DustTrak Aerosol Monitor 8520. The highest N of PM1.0 and PM10.0 were 0.0485 mg/shot/cm2 and 0.0766 mg/shot/cm2 mg/shot/cm2 safe than conventional chemical stripping process in term of health implications prevention and safety managements. beam size for Sample A, 0.0890 mg/shot/cm2 and 0.0634 mg/shot/cm2 and 0.1728 mg/shot/cm2 for Sample B and 0.0530 for Sample C, respectively. Laser paint removal technique is considered

4-tert-Butyl-N-[(2,6-dimethyl-phen-yl)carbamothio-yl]benzamide.

The asymmetric unit of the title compound, C20H24N2OS, consists of two crystallographically independent molecules. In each molecule, an intramolecular N—H⋯O hydrogen bond forms an S(6) ring motif. The dihedral angles between the terminal benzene rings in the two molecules are 75.52 (7) and 42.80 (7)°. In the crystal, intermolecular N—H⋯S interactions link the molecules into a chain along the c axis.

Ultrasound Speed of Polymer Gel Mimicked Human Soft Tissue within Three Weeks

A Polymer gel mimicked human soft tissue was being fabricated using a monomer named 2-Hydroxyl-Ethyl-Acrylate (HEA) with the present of gelatin. The readymade gel which is the concentration for HEA fixed at 5% was then undergoes an ultrasonic evaluation to test for the propagation of sound speed through it. Sonic Waves Analyzer is absolutely the most accurate technique to determine the aims (changes of speed as function of polymer structure /stiffness over time). The fixed frequency of transducers involved is at 500 kHz by using the seismic reflection concept. In the observation of relationship between the ultrasound propagation speeds as the day increased, the propagation speed still varies between 1390 to 1500 m/s which is still in the range of speed of sound for human tissue.

Estimation of Threshold Fluence, Absorption Coefficient and Thermal Loading of Car Coated Substrate in Laser Paint Removal

Threshold fluence (FT), absorption coefficient (α) and thermal loading (γ) were estimated on three types of car coated substrate by applying Beer-Lambert law. Cynosure Cynergy Pulse Nd:YAG was using to irradiate 54 substrate samples and the depth of coating removed (d) was obtained by using Alicona IFM G4. Depth of coating removed (d) versus laser fluence (F) graphs was plotted for each pulse width (PW), repetition rate (RR) and beam size (BS) considered by measuring the average of coating removal efficiency (ε). The best interceptions of certains ε with their X-axis were selected for each sample A, B and C, representing their general FT, α and γ respectively.

Effect of inorganic salts and glucose additives on dose–response, melting point and mass density of genipin gel dosimeters

Genipin gel dosimeters are hydrogels infused with a radiation-sensitive material which yield dosimetric information in three dimensions (3D). The effect of inorganic salts and glucose on the visible absorption dose-response, melting points and mass density of genipin gel dosimeters has been experimentally evaluated using 6-MV LINAC photons. As a result, the addition of glucose with optimum concentration of 10% (w/w) was found to improve the thermal stability of the genipin gel and increase its melting point (Tm) by 6 °C accompanied by a slight decrease of dose-response. Furthermore, glucose helps to adjust the gel mass density to obtain the desired tissue-equivalent properties. A drop of Tm was observed when salts were used as additives. As the salt concentration increased, gel Tm decreased. The mass density and melting point of the genipin gel could be adjusted using different amounts of glucose that improved the genipin gel suitability for 3D dose measurements without introducing additional toxicity to the final gel.

20‐N‐Ethyl‐1,8,14‐tri­hydroxy‐16β,18‐di­methoxy­lycoctonine

The title compound, C23H47NO5, has been isolated from Delphinium roylei for the first time. The molecular architechture comprises six fused rings, A–F. The six-membered rings, A and E, are in chair conformations, while ring D is in a distorted boat form. The seven-membered ring B is in a boat form and the remaining two five-membered rings, C and F, are in envelope conformations. The crystal structure is stabilized by O—H⋯O, C—H⋯O and C—H⋯N interactions.