Prognostic value of clinicopathological parameters in head and neck squamous cell carcinoma: a prospective analysis.

The prognostic weight of histological and biological factors was compared with that of known clinical prognostic factors in a population of 108 consecutive previously untreated patients with head and neck squamous cell carcinoma. Parameters studied were: tumour vascularisation, mitotic index, histological differentiation, nuclear grade, keratinisation, desmoplasia, growth pattern, inflammation, tumour emboli in peripheral vessels, keratins 6, 13, 19 immunohistochemical expression, cytofluorometric ploidy and S-phase. In multivariate analysis (Cox), only age and nodal status had a significant impact on the overall survival, whereas T stage was the only significant factor associated with locoregional failure. The cumulative incidence of metastases was correlated not only with age, T and N stage, but also with histological differentiation. All the other histological and biological factors studied failed to provide further prognostic information. These findings may help to select patients with high metastatic risk

A Mechanistic Study of Carbonic Anhydrase Enhanced Calcite Dissolution

Carbonic anhydrase (CA) has been shown to promote calcite dissolution (Liu, 2001, https://doi.org/10.1111/j.1755-6724.2001.tb00531.x; Subhas et al., 2017, https://doi.org/10.1073/pnas.1703604114), and understanding the catalytic mechanism will facilitate our understanding of the oceanic alkalinity cycle. We use atomic force microscopy (AFM) to directly observe calcite dissolution in CA‐bearing solution. CA is found to etch the calcite surface only when in extreme proximity (~1 nm) to the mineral. Subsequently, the CA‐induced etch pits create step edges that serve as active dissolution sites. The possible catalytic mechanism is through the adsorption of CA on the calcite surface, followed by proton transfer from the CA catalytic center to the calcite surface during CO2 hydration. This study shows that the accessibility of CA to particulate inorganic carbon (PIC) in the ocean is critical in properly estimating oceanic CaCO3 and alkalinity cycles

A Mechanistic Study of Carbonic Anhydrase Enhanced Calcite Dissolution

Carbonic anhydrase (CA) has been shown to promote calcite dissolution (Liu, 2001, https://doi.org/10.1111/j.1755-6724.2001.tb00531.x; Subhas et al., 2017, https://doi.org/10.1073/pnas.1703604114), and understanding the catalytic mechanism will facilitate our understanding of the oceanic alkalinity cycle. We use atomic force microscopy (AFM) to directly observe calcite dissolution in CA‐bearing solution. CA is found to etch the calcite surface only when in extreme proximity (~1 nm) to the mineral. Subsequently, the CA‐induced etch pits create step edges that serve as active dissolution sites. The possible catalytic mechanism is through the adsorption of CA on the calcite surface, followed by proton transfer from the CA catalytic center to the calcite surface during CO2 hydration. This study shows that the accessibility of CA to particulate inorganic carbon (PIC) in the ocean is critical in properly estimating oceanic CaCO3 and alkalinity cycles

An Atomic Force Microscopy Study of Calcite Dissolution in Seawater

We present the first examination of calcite dissolution in seawater using Atomic Force Microscopy (AFM). We quantify step retreat velocity and etch pit density to compare dissolution in seawater to low ionic strength water, and also to compare calcite dissolution under AFM conditions to those conducted in bulk solution experiments (e.g. Subhas et al., 2015, Dong et al., 2018). Bulk dissolution rates and step retreat velocities are slower at high and mid-saturation state (Ω) values and become comparable to low ionic strength water rates at low Ω. The onset of defect-assisted etch pit formation in seawater is at Ω ∼ 0.85 (defined as Ω_(critical)), higher than in low ionic strength water (Ω ∼ 0.54). There is an abrupt increase in etch pit density (from ∼10⁶ cm⁻² to ∼10⁸ cm⁻²) occurring when Ω falls below 0.7 in seawater, compared to Ω ∼ 0.1 in low ionic strength water, suggesting a transition from defect-assisted dissolution to homogeneous dissolution much closer to equilibrium in seawater. The step retreat velocity (v) does not scale linearly with undersaturation (1-Ω) across an Ω range of 0.4 to 0.9 in seawater, potentially indicating a high order correlation between kink rate and Ω for non-Kossel crystals such as calcite, or surface complexation processes during calcite dissolution in seawater

An Atomic Force Microscopy Study of Calcite Dissolution in Seawater

We present the first examination of calcite dissolution in seawater using Atomic Force Microscopy (AFM). We quantify step retreat velocity and etch pit density to compare dissolution in seawater to low ionic strength water, and also to compare calcite dissolution under AFM conditions to those conducted in bulk solution experiments (e.g. Subhas et al., 2015, Dong et al., 2018). Bulk dissolution rates and step retreat velocities are slower at high and mid-saturation state (Ω) values and become comparable to low ionic strength water rates at low Ω. The onset of defect-assisted etch pit formation in seawater is at Ω ∼ 0.85 (defined as Ω_(critical)), higher than in low ionic strength water (Ω ∼ 0.54). There is an abrupt increase in etch pit density (from ∼10⁶ cm⁻² to ∼10⁸ cm⁻²) occurring when Ω falls below 0.7 in seawater, compared to Ω ∼ 0.1 in low ionic strength water, suggesting a transition from defect-assisted dissolution to homogeneous dissolution much closer to equilibrium in seawater. The step retreat velocity (v) does not scale linearly with undersaturation (1-Ω) across an Ω range of 0.4 to 0.9 in seawater, potentially indicating a high order correlation between kink rate and Ω for non-Kossel crystals such as calcite, or surface complexation processes during calcite dissolution in seawater

Towards Sustainable Environment in G7 Nations: The Role of Renewable Energy Consumption, Eco-innovation and Trade Openness

Some of the globe’s most economically advanced nations make up the G7 (Canada, Japan, France, Germany, Italy, United States and United Kingdom). Nevertheless, in tandem with such strong economic growth, the environmental conditions in these nations have deteriorated, raising serious issues among stakeholders. Therefore, we examine the effect of eco-innovation and trade openness on CO2 emissions in G7 nations. We also take into account the role of renewable energy, economic growth and nonrenewable energy use using a dataset covering the period from 1990–2019. We employed recent econometric techniques such as slope heterogeneity (SH) and cross-sectional dependence (CSD), Westerlund cointegration, fully modified ordinary least square (FMOLS), dynamic ordinary least square (DOLS), panel quantile regression and panel causality tests to assess these associations. The outcomes of the CSD and SH tests disclosed that using a first-generation unit root test will produce biase outcomes. Furthermore, the outcomes of the Westerlund cointegration disclosed support long-run association between CO2 and its drivers. In addition, the results of the long-run estimators (FMOLS and DOLS) unveiled that nonrenewable energy and trade openness contribute to the damage to the environment while economic expansion, renewable energy and eco-innovation enhance the quality of the environment. Furthermore, the outcomes of GDP, REC and ECO curb CO2 while NREC energy and TO surge CO2. Finally, the outcomes of the panel causality test unveiled that CO2 emissions can be predicted by all the exogenous variables. Copyright © 2022 Olanrewaju, Irfan, Altuntaş, Agyekum, Kamel and El-Naggar

Redox linked flavin sites in extracellular decaheme proteins involved in microbe-mineral electron transfer

Extracellular microbe-mineral electron transfer is a major driving force for the oxidation of organic carbon in many subsurface environments. Extracellular multi-heme cytochromes of the Shewenella genus play a major role in this process but the mechanism of electron exchange at the interface between cytochrome and acceptor is widely debated. The 1.8 Å x-ray crystal structure of the decaheme MtrC revealed a highly conserved CX8C disulfide that, when substituted for AX8A, severely compromised the ability of S. oneidensis to grow under aerobic conditions. Reductive cleavage of the disulfide in the presence of flavin mononucleotide (FMN) resulted in the reversible formation of a stable flavocytochrome. Similar results were also observed with other decaheme cytochromes, OmcA, MtrF and UndA. The data suggest that these decaheme cytochromes can transition between highly reactive flavocytochromes or less reactive cytochromes, and that this transition is controlled by a redox active disulfide that responds to the presence of oxygen

Linking Financial Development and Environment in Developed Nation Using Frequency Domain Causality Techniques: The Role of Globalization and Renewable Energy Consumption

The topic of whether globalization, energy consumption and financial development can substantially reduce emissions during the globalization era remains unanswered. In this context, this research highlights empirical indications supporting this theoretical discord; assessing the effect of globalization, energy consumption and financial development on the CO2 emissions in Japan (utilizing a dataset that spans between 1990 and 2019). The study employed the Autoregressive Distributed Lag (ARDL) technique and frequency domain causality to probe these relationships. Unlike other conventional causality tests, the frequency domain causality test can capture causality at different frequencies. The findings from the ARDL analysis disclosed that globalization and renewable energy contribute to the mitigation of CO2 emissions while fossil fuel, economic growth and financial development caused an upsurge in CO2 in Japan. Furthermore, the frequency domain demonstrated that all the exogenous variables can forecast CO2 mostly in the long-term which implies that any policy initiated based on the exogenous variables will impact emissions of CO2. Based on the results obtained, Japan has to improve its financial systems and increase its use of renewable energy. Furthermore, Japan needs to restructure its policy regarding globalization owing to the fact that it contributes to the degradation of the environment. Since globalization is a major driver of economic growth, the government should concentrate on luring and licensing investors that use environmentally beneficial (net-zero) technology. Copyright © 2022 Mosleh, Al-Geitany, Lawrence Emeagwali, Altuntaş, Agyekum, Kamel, El-Naggar and Agbozo

Oval Domes: History, Geometry and Mechanics

An oval dome may be defined as a dome whose plan or profile (or both) has an oval form. The word Aoval@ comes from the latin Aovum@, egg. Then, an oval dome has an egg-shaped geometry. The first buildings with oval plans were built without a predetermined form, just trying to close an space in the most economical form. Eventually, the geometry was defined by using arcs of circle with common tangents in the points of change of curvature. Later the oval acquired a more regular form with two axis of symmetry. Therefore, an “oval” may be defined as an egg-shaped form, doubly symmetric, constructed with arcs of circle; an oval needs a minimum of four centres, but it is possible also to build polycentric ovals. The above definition corresponds with the origin and the use of oval forms in building and may be applied without problem until, say, the XVIIIth century. Since then, the teaching of conics in the elementary courses of geometry made the cultivated people to define the oval as an approximation to the ellipse, an “imperfect ellipse”: an oval was, then, a curve formed with arcs of circles which tries to approximate to the ellipse of the same axes. As we shall see, the ellipse has very rarely been used in building. Finally, in modern geometrical textbooks an oval is defined as a smooth closed convex curve, a more general definition which embraces the two previous, but which is of no particular use in the study of the employment of oval forms in building. The present paper contains the following parts: 1) an outline the origin and application of the oval in historical architecture; 2) a discussion of the spatial geometry of oval domes, i. e., the different methods employed to trace them; 3) a brief exposition of the mechanics of oval arches and domes; and 4) a final discussion of the role of Geometry in oval arch and dome design