ABSTRACT
In this study, we performed the physicochemical and electrochemical characterization of a decorated macrocyclic aluminium(iii) phthalocyanine complex (AlTMQNCAPc). Subsequently, the AlTMQNCAPc@MWCNT/GC electrode was used for the electrochemical detection of glucose and hydrogen peroxide (H2O2) by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry (CA). Moreover, the limit of detection, linear range, and sensitivity for glucose and H2O2 were investigated (CV: 2.5 nM L-1 and 25 nM L-1, 50-500 µM, 0.052 and 0.072 µA µmol cm-2; DPV: 3.1 nM L-1 and 18 nM L-1, 50-500 µM, 0.062 and 0.066 µA µmol cm-2 and CA: 10 nM L-1 and 20 nM L-1, 50-500 µM, 0.098 and 0.07 µA µmol cm-2, respectively). In addition, the AlTMQNCAPc@MWCNT/GC electrode showed good selectivity for the detection of glucose and H2O2 in the presence of common interfering substances, such as AA, DA, UA, glycine, l-cysteine, nitrite, Pb(ii), Cd(ii), Cu(ii), Co(ii), Hg(ii), Zn(ii), and glucose. For the detection of glucose and H2O2, the kinetic parameters, including the electron transfer coefficient and catalytic reaction rate constant, were also established. Finally, for usage in practical applications, the modified electrode was employed to achieve the quantitative detection of glucose and H2O2 in human urine and commercial samples of 3% H2O2, respectively.
ABSTRACT
A series of metal(II) complexes (M=Co (II), Ni(II) and Cu(II)) supported by Schiff base ligand (L=(E)-N'-((6-hydroxybenzo[d]oxazol-5-yl)methylene)isonicotinohydrazide) has been designed and developed from condensation of 6-hydroxybenzo[d]oxazole-5-carbaldehyde and isoniazid. The ligand (H2L) and its metal(II) complexes were structurally characterized utilizing a variety of physicochemical and spectroscopic approaches. The study shows that Schiff bases (H2L) act as monobasic tridentate ONO ligand and conform to octahedral geometry according to the general formula [M(HL)2]. Furthermore, the interaction of these complexes with CT-DNA was investigated at pH = 7.2, utilizing UV-visible absorption, and viscosity measurement. In order to determine the mechanism of binding of the metal(II) complexes to the B-DNA dodecamer, docking studies were conducted using an AutoDock Vina 1.2.0 tool. The photo induced cleavage reveals that the ligand (H2L) and its complexes have UV-visible photo nuclease properties against pUC19 DNA by agarose gel electrophoresis technique. Studies showed that the complexes evaluated firmly bind to CT-DNA via intercalative mode and provides a distinctive pattern of DNA binding.
Subject(s)
Coordination Complexes , Coordination Complexes/chemistry , DNA/chemistry , Isoniazid , Ligands , Molecular Docking Simulation , Schiff Bases/chemistryABSTRACT
A novel tetra-4-{(E)-[(8-aminonaphthalen-1-yl)imino]methyl}-2-methoxyphenol Co(ii) phthalocyanine (CoTANImMMPPc) was synthesized using a precursor protocol and characterized via electroanalytical and spectroscopic techniques. The FT-IR spectra of the synthesized compounds showed significant peaks corresponding to the functional groups of the precursors and phthalocyanine (Pc) compound. The mass and NMR spectra confirmed the formation of the target precursor compounds. A film of CoTANImMMPPc was deposited on the surface of an electrode and applied for the detection and monitoring of l-alanine and l-arginine. The cyclic voltammetric studies of l-alanine and l-arginine using the (CoTANImMMPPc/MWCNTs/GC) electrode showed a linear response in the range of 50-500 nM and the limit of detection was found to be 1.5 and 1.2 nM, respectively. Differential pulse voltammetry and chronoamperometry showed that the catalytic response for l-alanine and l-arginine is in the range of 50-500 nM with an LoD of 1.8 and 2.3 nM, respectively. The oxidation-active CoTANImMMPPc film significantly enhanced the current response in the chronoamperometric method and displayed a selective and sensitive response towards l-alanine and l-arginine in the presence of various other bio-molecules. The developed electrode showed good working stability and was applied for the analysis of real samples, which yielded satisfactory results. Therefore, CoTANImMMPPc-MWCNTs/GCE shows good analytical performance, is economical and produced via a simple synthetic method and can be applied as a sensor for the detection of l-alanine and l-arginine.
ABSTRACT
The progress made by the scientific community in emerging photovoltaic technologies over the past two decades has been outstanding. Numerous methods have been developed for the preparation of hybrid organic-inorganic perovskite solar cells. The power conversion efficiency has been up to 14% by a one-step vacuum deposition technique. A serious concern is the toxicity of the materials. In this review, several methods aimed at resolving these problems to some extent have been compiled, including eco-friendly synthesis. Further efficiency enhancements are expected following optimization, and a better fundamental understanding of the internal electron charge transfer, electron-hole diffusion to the corresponding layers, flexibility, and stability-dependent bandgaps is reported. This paper explores the green synthesis of organic-inorganic perovskites for industrialization. Concerning the above facts, a simple low-cost model called "dispersed photovoltaic cells" is presented.
ABSTRACT
Two hundred patients suffering from tuberculosis (TB) of the spine with neurological complications were the subjects of this review. They were graded according to the Frankel system into--A: complete neurological deficit; B: sparing of some sensation; C: sparing of sensation but no useful motor function; D: sparing of sensation and useful motor function; and E: no deficits. Investigations carried out included detailed neurological assessment, radiography, contrast myelography and, in the later stages of the study, spinal computerized tomography (CT) scan. The authors believe that contrast myelography provides the best indication of spinal compression in TB spine. Treatment was by surgical decompression followed by chemotherapy. The surgical approach for thoracic spine disease was by the anterior transthoracic route. Cervical lesions were also approached by the anterior route, lateral to the carotid vessels. Unexpected findings during operation included lymphoma, plasmacytoma, non-tuberculous granulation tissue, salmonella osteomyelitis and tumour metastasis. Ten patients died during the postoperative period, all of whom had extensive systemic TB. When indicated, antituberculous drugs were administered postoperatively for two years and immobilization was done in a plaster cast for 3 months. Only 30 patients showed partial recovery. Improvement was found to be related to the grade of deficit; thoracic lesions with severe neurological deficits showed the least improvement while lumbar disease had the best outcome. The study recommended a combination of surgery and chemotherapy for all cases of TB spine with neurological deficits after a short delay during which respiratory function should be improved. The surgery should aim at decompression of the cord by removal of pus, granulation tissue and sequestra, with internal splintage with bone grafts to reduce the hospital stay. Conservative treatment is unwise because it is not always possible to distinguish between TB and neoplastic lesions.
Subject(s)
Tuberculosis, Spinal/complications , Female , Humans , Malawi/epidemiology , Male , Paraplegia/etiology , Spinal Cord Compression/etiology , Tuberculosis, Spinal/epidemiology , Tuberculosis, Spinal/therapyABSTRACT
Tuberculosis is still a major cause of spinal compression in the developing countries. In this study 200 patients presenting with neurological lesions secondary to tuberculosis of the spine have been classified according to the Frankel classification and the results evaluated. A combination of surgical decompression and chemotherapy is advocated. The dangers of non-operative treatment are discussed.
Subject(s)
Spinal Cord Compression/etiology , Tuberculosis, Spinal/complications , Humans , Laminectomy , Spinal Cord Compression/diagnosis , Spinal Cord Compression/surgery , Tuberculosis, Spinal/diagnosis , Tuberculosis, Spinal/drug therapyABSTRACT
Arterialized venous channels in the arteriovenous malformations of the brain represent persistent embryonic veins. The configuration of these veins resembles embryonic venous channels. Their microscopic features also resembles those of the foetal cerebral veins. The intimal liming of the persisting embryonic veins suggests the approximate age of the foetus at which the arteriovenous fistual is likely to have occurred.
Subject(s)
Intracranial Arteriovenous Malformations/embryology , Veins/embryology , Adolescent , Biopsy , Cerebral Arteries/pathology , Cerebrovascular Circulation , Endothelium/pathology , Female , Fibromuscular Dysplasia/pathology , Humans , Intracranial Arteriovenous Malformations/pathology , Pregnancy , Veins/pathologyABSTRACT
A young man developed a paraplegia of relatively sudden onset. A myelogram revealed an obstruction at the T8 level. Laminectomy at T7-9 disclosed a remarkably thick dura mater compressing the spinal cord. Microscopic examination of the dura mater was suggestive of syphilitic granulation tissue. Serum and CSF samples examined for evidence of syphilis were strongly reactive.
Subject(s)
Meningitis/complications , Paraplegia/etiology , Adult , Dura Mater/pathology , Humans , Hypertrophy/pathology , MaleABSTRACT
In the arteriovenous malformations of the posterior fossa the arterial feeders and the dural venous sinuses can be identified in anatomical terminology. The arterialised veins which do not conform to adult anatomical descriptions represent the persistent embryonic veins of the metencephalic and myelencephalic segments of the developing brain. These can be identified and described when related to the embryo.
Subject(s)
Intracranial Arteriovenous Malformations/pathology , Veins/embryology , Arteries/embryology , Brain/embryology , Cerebellum/blood supply , Humans , Intracranial Arteriovenous Malformations/embryologyABSTRACT
The basic anatomy of the arteriovenous malformations of the dura is similar to that of the internal carotid (pial) malformations, as the arterial feeders in both these lesions arise from the internal carotid artery in the embryo. The venous drainage occurs through definite channels into the major venous sinuses. Therefore, the dural and the pial malformations should be classified together. The scalp malformations have no features similar to these groups. The prominent occipital artery is not necessarily the primary feeder. Whenever a prominent occipital artery is seen, special efforts must be made to locate the primary dural feeders arising from the internal carotid artery.
Subject(s)
Dura Mater/blood supply , Intracranial Arteriovenous Malformations/diagnostic imaging , Carotid Artery Diseases/diagnostic imaging , Cerebral Angiography , Cerebral Arteries , Cranial Sinuses/embryology , Humans , Intracranial Arteriovenous Malformations/embryology , Meningeal Arteries , Veins/embryologyABSTRACT
The diencephalic arteriovenous malformation is produced by the posterior cerebral, posterior choroidal, and anterior choroidal arteries. The abnormal arterialised vessels seen in these malformation represent dorsal and ventral diencephalic veins. The drainage of the shunted blood is primarily into the transverse sinus. This is later diverted medially into the great cerebral vein, with the formation of the basal vein. The medial drainage, in keeping with the normal developmental pattern, is seen frequently. The presence and locations of angiomas are very variable and do not follow any predictable pattern.
Subject(s)
Diencephalon/blood supply , Intracranial Arteriovenous Malformations/diagnostic imaging , Diencephalon/embryology , Humans , Intracranial Arteriovenous Malformations/embryology , Phlebography , Veins/embryologyABSTRACT
The arterial components of the telencephalic arteriovenous malformations arise from the anterior cerebral and middle cerebral arteries. The complexity of the development process in this region obscures the fundamental segmental pattern. There are three regions where the primitive pial vessels cross at right angles. They are: a) over the convexity of the cerebral hemispheres, b) in the Sylvian territory, c) in the region of the basal ganglia. The malformations over the surface drain into the superior sagittal sinus. The Sylvian and deep telencephalic malformations drain primarily into the tentorial sinus, and this is often replaced by a medial drainage into the internal cerebral vein through the tributaries of the basal vein.
Subject(s)
Intracranial Arteriovenous Malformations/diagnostic imaging , Telencephalon/blood supply , Basal Ganglia/blood supply , Humans , Intracranial Arteriovenous Malformations/embryology , Phlebography , Veins/embryologySubject(s)
Cerebral Hemorrhage/diagnosis , Hematoma/diagnosis , Adult , Cerebral Hemorrhage/surgery , Child, Preschool , Cranial Fossa, Posterior , Female , Hematoma/surgery , Humans , MaleABSTRACT
The course and direction of persistent foetal venous channels are easily defined in the relatively simple segmental portions of the nervous system, such as the spinal cord, the myelencephalon, the metencephalon, and the mesencephalon. In sites were embryonic development is more complicated, like the diencephalon and the telencephalon, rapid growth and folding of the cortex complicate the patterns of the foetal blood vessels. Arteriovenous malformations in such sites are correspondingly more complex.