Phthalocyanines in batteries and supercapacitors

Numerous are the ways through which phthalocyanines have been put into very good use. The on-going search for new energy storage and conversion systems has made phthalocyanines even prettier as alternatives to metal and metal oxide catalysts because of their lower cost. This review article looks through a very narrow window of the applications of phthalocyanines in batteries and supercapacitors as a means of improving the qualities such as cycle property, energy density, capacity, open circuit voltage, etc, of these devices.

Template-directed electrochemical synthesis of cobalt phthalocyanine nanowires

The development of novel nanomaterials has been in the fore front of research in recent years due to the unusually outstanding properties of such materials. Metallophthalocyanines are well known to be of very good use in a wide range of applications. Nanomaterials based on this class of compounds could potentially have better qualities than the "parent" molecules. The electrochemical synthesis of cobalt phthalocyanine nanowires and the characterization using scanning electron microscope are presented. This is the first step towards a move to harnessing the potential of this class of nanomaterials for a wide range of new possible applications.

Spectrophotometric and electrochemical studies of the interaction between iron(II) tetrasulfophthalocyanine and histamine

The interaction between iron(II) tetrasulfophthalocyanine ([ Fe II TSPc ]4+) and histamine results in the oxidation of the central metal by oxygen in the former, with the formation of a complex denoted as [(His) Fe III TSPc ]3− (where His = histamine). The rate constant for the formation of the complex is kf = 2.41 × 10−2 dm 3.mol−1.s−1 and an equilibrium constant of 6.3 dm3.mol-1 was obtained. The oxidation state of the central metal of [ Fe II TSPc ]4− before and after the coordination of histamine is confirmed by spectroelectrochemistry. Further electrochemical oxidation of this [( His ) Fe III TsPc ]3− derivative results in a metal-based process proposed to involve an Fe IV phthalocyanine species.

Electrochemical nitric oxide sensor preparation: a comparison of two electrochemical methods of electrode surface modification

Platinum electrodes modified with Mn(II) 5-(N-(8-pyrrole-yl-3,6-dioxa-1-aminooctane)phenylamide-10,15,20-trimethoxyphenylporphyrin (Mn(II)triOMeTCPPyP) using multi-sweep cyclic voltammetry and differential pulse amperometry were evaluated as electrocatalytic surfaces for the oxidation of nitric oxide. The electrodes modified using the pulse amperometric approach were more sensitive towards the detection of nitric oxide. The increased sensitivity led to the attainment of a wider linear dynamic range for the quantification of nitric oxide.

Cell-compatible array of three-dimensional tip electrodes for the detection of nitric oxide release

An array of electrodes on which cells could be grown directly was fabricated using silicon anisotropic etching and a thick-photoresist process and employed for the detection of nitric oxide (NO) released from a population of adherently growing human umbilical vein endothelial cells (HUVEC). The electrodes are tip-shaped and are 40 microm high of which only the top 15 microm are exposed Pt-tips. After electrochemical induced modification of the exposed Pt tips using Ni phthalocyanine the individual addressable electrode tips were sensitive and selective for the detection of NO at an applied constant potential of 750 mV. The silicon nitride insulation of the lower part of the tip electrodes prevented the death of the cells upon the application of the working potential at which NO was detected. It also helped to avoid the perturbation of the integrity of the sensing chemistry imparted on the electrode surface that could have resulted from the contact of the adherently growing cells with the active electrode surface. The release of nitric oxide from HUVEC was successfully monitored with different numbers of tip electrodes simultaneously connected as combined working electrode.

Simultaneous detection of the release of glutamate and nitric oxide from adherently growing cells using an array of glutamate and nitric oxide selective electrodes

The simultaneous detection of nitric oxide and glutamate using an array of individually addressable electrodes, in which the individual electrodes in the array were suitably modified with a highly sensitive nitric oxide sensing chemistry or a glutamate oxidase/redox hydrogel-based glutamate biosensor is presented. In a sequence of modification steps one of the electrodes was covered first with a positively charged Ni porphyrin entrapped into a negatively charged electrodeposition paint followed by the manual modification of the second working electrode by a bienzyme sensor architecture based on crosslinked redox hydrogels with entrapped peroxidase and glutamate oxidase. Adherently growing C6-glioma cells were grown on membrane inserts and placed in close distance to the modified sensor surfaces. The current responses recorded at each electrode after stimulation of glutamate and NO release by means of K+ and bradykinin clearly demonstrate the ability of the individual electrode in the array to detect the analyte towards which its sensitivity and selectivity was targeted without interference from the neighbouring electrode or other analytes present in the test mixture.

Functionalised electrode array for the detection of nitric oxide released by endothelial cells using different NO-sensing chemistries

In a preliminary study aimed at developing strategies for the simultaneous detection of various biologically important molecules, a procedure is described that allows the electrochemical detection of nitric oxide (NO) released by a population of human umbilical vein endothelial cells (HUVEC) by using an array of electrodes comprising three individually addressable electrodes. Each electrode in the array was modified with a different NO-sensitive electrocatalyst, thereby demonstrating the possibility of modifying the individual electrodes in an array with different sensing chemistries. This study opens a doorway to the development of arrays of electrodes for the simultaneous detection of multiple analytes in a complex environment by suitably tailoring the sensitivity and selectivity of each electrode in the array to a specific analyte in the test medium.

Dual Microelectrodes for Distance Control and Detection of Nitric Oxide from Endothelial Cells by Means of Scanning Electrochemical Microscope

Dual Pt disk microelectrodes consisting of a 10-microm distance sensor and a 50-microm nitric oxide sensor were prepared. The 50-microm electrode was modified with Ni(4-N-tetramethyl)pyridyl porphyrin enclosed in the polymer network of a negatively charged electrodeposition paint. This paint prevented the dissolution of the otherwise soluble porphyrin in the aqueous test medium due to charge interactions. It also denied negatively charged ions in the analyte solution access to the electrode surface by electrostatic repulsion, thereby preventing interference from anions such as nitrite, nitrate, and ascorbate. With the aid of a scanning electrochemical microscope, it was possible to use the distance sensor by recording the negative feedback effect on the reduction of molecular oxygen to "guide" the nitric oxide sensor to various known distances from a layer of adherently growing human umbilical vein endothelial cells for the detection of nitric oxide released from the cells upon stimulation with bradykinin. The use of the distance sensor made it possible to preserve the integrity of the adherently growing cells concomitantly with the modified electrode by preventing the deterioration of the modifying layer during the distance adjustment step.

Evaluation of redox mediators for amperometric biosensors: Ru-complex modified carbon-paste/enzyme electrodes

The properties of reagentless amperometric biosensors are mainly governed by the interaction of the used redox enzyme and the redox mediators used to facilitate the electron-transfer reaction. Both the used redox mediators and the redox enzymes differ concerning their hydrophilicity and their properties within the matrix of a carbon-paste electrode. Since there is no general procedure which is applicable for any enzyme in combination with any redox mediator, optimisation is necessary for each possible combination. Three approaches for the development of biosensors were investigated using carbon-paste electrodes enriched with redox mediator as a base in all sensor architectures. A class of redox mediators with the common formula Ru(LL)(2)(X)(2) (where LL are 1,10-phenantroline or 2,2'-bipyridine type ligands, and X is an acido ligand) was investigated. In the first approach, enzymes were integrated into the carbon paste; in the second, the enzymes were adsorbed on the surface of the mediator-containing carbon-paste electrode and held in place by a Nafion film; and in the third approach, enzymes were entrapped in polymer films, which were electrochemically deposited onto the electrode's surface. The properties of the obtained biosensors strongly depend on the sensor architecture and the specific features of the used enzyme. Thus, our investigation using three different sensor architectures can provide valuable information about the possible interaction between a specific enzyme and a redox mediators with specific properties.

Ganglia: the patient's perception

This study investigates the concerns of 50 patients with ganglia and their reasons for primary care consultation and referral to a hand unit. Although a minority of patients sought advice and treatment because of pain, more (38%) were concerned about the cosmetic appearance and a significant number (28%) were concerned that their ganglion was a malignant growth. The general practitioners referred 70% of patients to the hand clinic for "excision of the ganglion" and 30% for further "advice and treatment". However, 74% of patients were satisfied with aspiration of the ganglion and general advice.

Motor racing accidents at Brands Hatch, 1988/9

Little is known about the incidence of injury to race track motor-cyclists and car drivers. In a 1-year study at Brands Hatch, 70 of 33,184 competitors required hospital treatment. We found this injury rate to be higher than on the public highway. However, the anatomical distribution of injury caused by motor-bike accidents is similar to that found on the public highway. Motor-cyclists are more likely than car drivers to sustain limb trauma requiring outpatient treatment only. The number of participants requiring admission to hospital is broadly similar for car and bike races, being less than 0.1%.