Relative Proportions Of Different Types Research Articles

A carbon fiber paper based electrode of high activity for electro-oxidation of aqueous sulfur dioxide

Significant improvements in the activity of a carbon-based electrode for the electro-oxidation of aqueous sulfur dioxide were obtained by introducing surface oxygen functionalities through the anodization of carbon fiber paper (CFP) in sulfuric acid solution. Electrodes of varying surface oxygen content (2.9 atomic% to 25.6 atomic%) and relative proportion of different types of oxygen functional groups were obtained by changing the anodization potential and the concentration of sulfuric acid. The activity of the optimal electrode was quantified by exchange current density and charge transfer resistance, respectively. The exchange current density was about 2.17-times the pristine CFP electrode (17.6 × 10−4μA cm−2 compared to 8.09 × 10−4μA cm−2). The morphological and structural changes in the electrode on anodization were determined using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Raman analysis. The chemical analysis of the electrode surface, done using X-ray photoelectron spectroscopy (XPS), showed a strong correlation between the electrode’s activity and the ratio of the percentage of hydroxyl groups to the sum of percentages of epoxy and carbonyl groups. The electrode performed well in an accelerated stability test based on cyclic voltammetry for over 1000 cycles.

A reappraisal of the freehold property market in late medieval England

AbstractThis article re-examines the late medieval market in freehold land, the extent to which it was governed by market forces as opposed to political or social constraints, and how this contributed to the commercialisation of the late medieval English economy. We employ a valuable new resource for study of this topic in the form of an extensive dataset on late medieval English freehold property transactions. Through analysis of this data, we examine how the level of market activity (the number of sales) and the nature of the properties (the relative proportions of different types of asset) varied across regions and over time. In particular, we consider the impact of exogenous factors and the effects of growing commercialisation. We argue that peaks of activity following periods of crisis (Great Famine and Black Death) indicate that property ownership became open to market speculation. In so doing, we present an important new perspective on the long-term evolution of the medieval English property market.

Violent and Nonviolent Crimes Against Sex Workers: The Influence of the Sex Market on Reporting Practices in the United Kingdom.

Previous research has shown that sex workers experience extremely high rates of victimization but are often reluctant to report their experiences to the police. This article explores how the markets in which sex workers operate in the United Kingdom impact upon the violent and nonviolent crimes they report to a national support organization and their willingness to report victimization to the police. We use a secondary quantitative data analysis of 2,056 crime reports submitted to the U.K. National Ugly Mugs (NUM) scheme between 2012 and 2016. The findings indicate that although violence is the most common crime type reported to NUM, sex workers operating in different markets report varying relative proportions of different types of victimization. We also argue that there is some variation in the level of willingness to share reports with the police across the different sex markets, even when the types of crime, presence of violence, and other variables are taken into account. Our finding that street sex workers are most likely to report victimization directly to the police challenges previously held assumptions that criminalization is the key factor preventing sex workers from engaging with the police.

The Role of Crisis in the English Property Market, 1300-1500: A Reappraisal

This paper re-examines the late medieval market in freehold land, the extent to which it was governed by market forces as opposed to political or social constraints, and how this contributed to the commercialisation of the late medieval English economy. We employ a valuable new resource for study of this topic in the form of an extensive dataset on late medieval English freehold property transactions. Through analysis of this data, we examine how the level of market activity (the number of sales) and the nature of the properties (the relative proportions of different types of asset) varied across regions and over time. In particular, we consider the impact of exogenous factors such as war, plague and political crises, and the effects of growing commercialisation. In so doing, we present an important new perspective on the long-term evolution of the medieval English property market.

Failure of diamond grains at the working surface of grinding wheels

Diamond grinding wheels are widely used in industry. In Russia, 5.5‐6.5 million carats of synthetic diamond powder is used each year for the production of wheels with organic powder, while 2.5‐3 million carats are used for the production of wheels with metal binder. Wheels with metal binder are employed in machining regular and fancy glass. However, the performance of Russian wheels does not match that of imported wheels. To create new diamond wheels with improved performance, we must study the failure of diamond grains in grinding so as to maximize the number of cutting grains on the wheel’s working surface. There are no literature data on the relative proportions of different types of diamond-grain failure during grinding. Therefore, it is of interest to analyze the failure of diamond grains at the working surface of wheels with organic and metallic binders. Visual inspection of the working surfaces of various diamond wheels permits the identification of the following models: 1) disintegration of the abrasive grains; 2) shift of the grains; 3) local rotation of the grains.

Histochemical staining patterns of muscle fibres in the gastrocnemius, soleus and anterior tibial muscles of the adult cat, as viewed in serial sections stained for lipids and succinic dehydrogenase.

The histochemical staining patterns of fibres in the gastrocnemius, soleus and anterior tibial muscles of the adult cat were investigated in serial sections stained for lipids, succinic dehydrogenase and NADH2 tetrazolium reductase. In the gastrocnemius and anterior tibial muscles, fibres of four different staining patterns were described, three of which were regarded as corresponding to those of the FF, FR and S fibres defined in the cat by Burke et al. (1973). The fourth fibre type, which was not always recognized, showed a spectrum of staining properties intermediate between those of the presumed FF and FR fibres. In the soleus muscle the majority of fibres exhibited an appearance which was similar but not identical to that of the S fibres of the composite muscles. A small percentage of the soleus fibres showed atypical staining properties and were believed to correspond to the fast contracting units observed in this muscle (Hammarberg & Kellerth, in preparation). For all three muscles the relative proportion of different types of muscle fibres were calculated, as well as the distribution of fibre diameters within each type.

Physical, mechanical, and viscoelastic properties of natural rubber vulcanizates cured with new binary accelerator system

AbstractNatural rubber was vulcanized with a new binary accelerator system based on 1‐phenyl‐2,4‐dithiobiuret (DTB) and dicyclohexyl benzothiazyl sulfenamide. A significant reduction in cure time was observed with the addition of DTB. The cure kinetics was investigated and the activation energy was determined. The mechanical properties were improved by adding DTB, and the maximum values are shown at an optimum concentration. Estimates of the concentration of crosslinks and of the relative proportions of different types of crosslinks were made by the chemical characterization of the vulcanizates. The crosslink densities obtained from swelling measurements and stress–strain measurements were compared with those obtained from modulus measurements. All of them follow a similar trend and support the observed mechanical properties. A dynamic mechanical analysis of the mixes was carried out and the activation energy was determined from Arrhenius plots. The glass‐transition temperature was found to increase with the increase in crosslink density and frequency of measurements. The stress–strain curves were found to not deviate from the strain crystallizing nature of natural rubber. The mechanical properties, network characterization, and processing characteristics were used to optimize the DTB concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2193–2203, 2003

Detrimental vascular effects of lysophosphatidylcholine is limited by other phospholipid components of low-density lipoprotein.

Current consensus suggests that lysophosphatidylcholine is the major detrimental factor in oxidized low-density lipoprotein that may contribute to the alterations of vasomotor responses associated with atherosclerosis. This study investigated the influences of lysophosphatidylcholine and major lipid components in oxidized low-density lipoprotein on vascular relaxation. We also determine if there was any interaction between these phospholipid components on relaxation. Porcine coronary artery rings were incubated with lysophosphatidylcholine, phosphatidylcholine or sphingomyelin. After contraction by the thromboxane A2 mimetic U46619, rings were relaxed with bradykinin and calcium ionophore A23187. Lysophosphatidylcholine with a higher proportion of stearoyl-lysophosphatidylcholine to palmitoyl-lysophosphatidylcholine ratio caused greater reduction of relaxational responses. While phosphatidylcholine and sphingomyelin had no effect on vascular relaxation, they reduced the ability of lysophosphatidylcholine to impair vascular relaxation. Our results thus suggested that the effectiveness of oxidized low-density lipoprotein at inhibiting vasodilatory responses may be determined by the relative proportion of different types of lysophosphatidylcholine as well as the amount of other phospholipid components: phosphatidylcholine and sphingomyelin.

Remodeling of Synaptic Membranes after Induction of Long-Term Potentiation

Several morphological changes of synapses have been reported to be associated with the induction of long-term potentiation (LTP) in the CA1 hippocampus, including an transient increase in the proportion of synapses with perforated postsynaptic densities (PSDs) and a later occurrence of multiple spine boutons (MSBs) in which the two spines arise from the same dendrite. To investigate the functional significance of these modifications, we analyzed single sections and reconstructed 134 synapses labeled via activity using a calcium precipitation approach. Analyses of labeled spine profiles showed changes of the spine head area, PSD length, and proportion of spine profiles containing a coated vesicle that reflected variations in the relative proportion of different types of synapses. Three-dimensional reconstruction indicated that the increase of perforated spine profiles observed 30 min after LTP induction essentially resulted from synapses exhibiting segmented, completely partitioned PSDs. These synapses had spine head and PSD areas approximately three times larger than those of simple synapses. They contained coated vesicles in a much higher proportion than that of any other type of synapse and exhibited large spinules associated with the PSD. Also the MSBs with two spines arising from the same dendrite that were observed 1-2 hr after LTP induction included a spine that was smaller and a PSD that was smaller than those of simple synapses. These results support the idea that LTP induction is associated with an enhanced recycling of synaptic membrane and that this process could underlie the formation of synapses with segmented PSDs and eventually result in the formation of a new, immature spine.

Labour quality and aggregate real-wage dynamics

The real wage plays an important role in many aggregate econometrics studies of the labour market. However, average wages, like any other average quantity, can change for two reasons – either through an underlying movement in the earnings potential of a unit of labour of given quality or, alternatively, through compositional changes which alter the relative proportions of different types of labour within the employed labour force. Using data from the General Household Survey to estimate earnings functions, the paper seeks to examine the contribution of these two factors for Britain from 1979 to 1989. It is shown that in periods of rising unemployment compositional changes can have a bigger effect on real-earnings growth than any underlying change in reward to labour of give quality. This raises the question of what economists actually are measuring when considering the behaviour of the aggregate real wage.

Use of histopathology services by general practitioners: recent changes in referral practice.

To determine the nature and magnitude of the histopathological workload generated by specimens received from general practitioners and to assess the trends in referral practice. All material submitted by general practitioners to the Leicester district histopathology service from 1989 to January 1993 was identified from departmental records. All GP referrals from October to December 1992 were also analysed. Total numbers of referrals from all sources were used for comparison. Specimens were also analysed according to diagnostic categories. There has been a progressive rise, both in the absolute number and the proportion of specimens relative to other surgical specimens submitted by GPs. Most are skin biopsy specimens. There were clear changes over the study period in the relative proportion of different types of lesions received, with a substantial increase in samples of benign naevi and papillomas. There was some evidence of a corresponding decrease in the number of these lesions submitted by hospital practitioners. The number of malignant skin tumours from GPs was small and the proportion had not increased over the study period. Histopathological workload generated by GPs is increasing but it still represents a small proportion of the total. The major increase is in benign skin lesions.

The wear of diamonds in impregnated diamond bit drilling

The wear of diamonds in impregnated diamond microbits was investigated in the laboratory by drilling a variety of rock types. The wear was studied by optical and scanning electron microscopy after drilling under a range of bit pressures, rates of advance, and rotational velocities using bits of different diamond size and concentration. The nature of the diamond wear modes did not vary with the drilling conditions but the relative proportions of different types of diamond wear changed with drilling performance. For stable drilling in any given rock type a characteristic threshold pressure existed above which desirable microfracture of the exposed diamonds was promoted over undesirable wear flat generation. The flats are produced by a sliding wear mode with the silicate minerals ploughing plastic grooves in the heated surfaces of the diamonds. Microfracture mode is the result of progressive growth and coalescence of cleavage microcracks promoted by the cyclical stresses experienced by the diamonds at pressures sufficient to cause indentation of the rock.

Development of bacterial plaque in the oral cavity

Dental plaque may be defined as bacterial aggregations upon the teeth and other solid structures inserted in the oral cavity. It is formed by oral microorganisms which attach to the teeth in sheltered areas along the gingival margin, on the approximal surfaces, and in pits and fissures on the masticatory surfaces. The plaque increases in quantity either by multiplication of already attached organisms, or by continuous addition to the deposits of bacteria from the saliva. Structural analyses indicate that the organisms are held together in an exracellular matrix partly produced by the organisms and partly derived from saliva. The microflora of plaque is complex and shows great individual variation. There are also characteristic differences in plaque from different sites on the teeth. Thus dento-gingival plaque is qualitatively different from that of the occlusal fissures. Furthermore, the relative proportion of different types of microorganisms may vary with the age of the deposit. Such information must be taken in consideration when attempts are made to develop chemical agents for the purpose of inhibiting plaque formation in order to prevent periodontal disease and caries.

Types of error in free recall

If the free recall of unrelated word lists depends on one memory store, then although the absolute number of errors may change as recall proceeds there is no reason for the relative proportions of different types of error to change. On the other hand, if recall consists of output from a short-term store which employs acoustic coding, followed by retrieval from a long-term store with different characteristics, a change in the proportions of errors would be expected. The results support the latter proposition.

The Relative Proportion of Different Types of Cells in Blood and Lymphoid Organs of Normal Rats

Lymphoid cells, especially the small ones, fixed and stained by the ordinary methods, do not show sufficient morphological differences to be classified according to their relative maturity as is possible with the granular leucocytes. Difference of opinion thus exists over the developmental potency of the small blood lymphoid cells, and the exact stage of development of the small tissue lymphoid cells is not definitely determined. No further progress in our knowledge of these cells is likely to be made by the old methods of fixation and staining for study. Stained with neutral red and janus green supravitally, however, the lymphoid cells present some very important morphological features which may be used as a basis for their finer differentiation. These features are: (1) the degree of opacity of the cytoplasm, (2) the number and size of mitochondria, and (3) the number of neutral red bodies. We have been able to divide the lymphoid cells, irrespective of their sizes, into 3 types, namely: lymphoblasts, intermediate forms, and lymphocytes. The lymphoblasts have opaque cytoplasm, abundant, coarse mitochondria but no, or very few, neutral red bodies. The lymphocytes have clear cytoplasm, fine, scanty mitochondria, but numerous neutral red bodies. The intermediate forms, as their name implies, are morphologically intermediate between the lymphoblasts and lymphocytes, and are therefore presumably older than the lymphoblasts but younger than the lymphocytes. This classification is used in the present supravital study of the lymphoid cells of the blood, spleen and lymph nodes of a large number of normal rats. The relative proportion of cells is fairly constant in all the animals studied. In Tables I and II the average values of the counts on the blood of 20, and those on the lymphoid organs of 7 animals are presented.