The stability of onoratoite, Sb8O11Cl2, in the supergene environment

2014 ◽  
Vol 78 (7) ◽  
pp. 1671-1675 ◽  
Author(s):  
Adam J. Roper ◽  
Peter Leverett ◽  
Timothy D. Murphy ◽  
Peter A. Williams
Keyword(s):  
Significant Influence ◽  
Secondary Phase ◽  
Low Ph ◽  
Stable Phase ◽  
Supergene Zone ◽  
A Value ◽  
Solubility Studies ◽  
The Stability ◽  
Very High

AbstractSynthesis and solubility studies of onoratoite have been undertaken to determine the role of this rare secondary phase in the immobilization of Sb and the conditions responsible for its formation in the supergene zone. Solubility studies were undertaken at 298.15 K. A value of ΔGfθ (Sb8O11Cl2, s, 298.15 K) = –2576 ±12 kJ mol–1 was derived. Calculations involving sénarmontite, Sb2O3, klebelsbergite, Sb4O4SO4(OH)2 and schafarzikite, FeSb2O4, show that onoratoite is a thermodynamically stable phase only at negligible activities of SO42–(aq) and low activities of Fe2+(aq), at low pH and very high activities of Cl–(aq). This explains why onoratoite is such a rare secondary phase and why it cannot exert any significant influence on the dispersion of Sb in the supergene environment.

The stability of the rare sodium antimonate, brizziite, and it's role in Sb mobility

2018 ◽  
Vol 82 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Adam J. Roper ◽  
Peter Leverett ◽  
Timothy D. Murphy ◽  
Peter A. Williams
Keyword(s):  
Significant Influence ◽  
High Salinity ◽  
Secondary Phase ◽  
Stable Phase ◽  
A Value ◽  
Mineral Associations ◽  
Solubility Studies ◽  
The Stability ◽  
Natural Settings

ABSTRACTSynthesis and solubility studies of brizziite, NaSbO3, have been undertaken to determine the possible role of this rare secondary phase in the immobilization of Sb under supergene conditions and the conditions responsible for its formation in the supergene zone. Solubility studies were undertaken at T = 298.15 K. A value of ΔGfө) (NaSbO3, s, 298.15 K) = –806.66 ± 1.4 kJ mol–1 was derived. Calculations involving tripuhyite, FeSbO4, byströmite, MgSb2O6, ordoñezite, ZnSb2O6 and rosiaite, PbSb2O6, show that brizziite is a thermodynamically stable phase only at negligible activities of Pb2+(aq) at high pH and high salinity. Calculations involving mopungite Na[Sb(OH)6] combined with reported mineral associations suggest that mopungite is the thermodynamically unstable precursor to brizziite and its presence in natural settings must be due to kinetic stability. This explains why brizziite is such a rare secondary phase and therefore why it cannot exert any significant influence on the dispersion of Sb in the supergene environment.

scholarly journals Determining the Role of Acidity, Fate and Formation of IEPOX-Derived SOA in CMAQ

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 707
Author(s):  
Petros Vasilakos ◽  
Yongtao Hu ◽  
Armistead Russell ◽  
Athanasios Nenes
Keyword(s):  
Significant Influence ◽  
Organic Aerosol ◽  
Liquid Water Content ◽  
Anthropogenic Emissions ◽  
So2 Emissions ◽  
Aerosol Acidity ◽  
A Value ◽  
Future Emission ◽  
The Impact

Formation of aerosol from biogenic hydrocarbons relies heavily on anthropogenic emissions since they control the availability of species such as sulfate and nitrate, and through them, aerosol acidity (pH). To elucidate the role that acidity and emissions play in regulating Secondary Organic Aerosol (SOA), we utilize the 2013 Southern Oxidant and Aerosol Study (SOAS) dataset to enhance the extensive mechanism of isoprene epoxydiol (IEPOX)-mediated SOA formation implemented in the Community Multiscale Air Quality (CMAQ) model (Pye et al., 2013), which was then used to investigate the impact of potential future emission controls on IEPOX OA. We found that the Henry’s law coefficient for IEPOX was the most impactful parameter that controls aqueous isoprene OA products, and a value of 1.9 × 107 M atm−1 provides the best agreement with measurements. Non-volatile cations (NVCs) were found in higher-than-expected quantities in CMAQ and exerted a significant influence on IEPOX OA by reducing its production by as much as 30% when present. Consistent with previous literature, a strong correlation of isoprene OA with sulfate, and little correlation with acidity or liquid water content, was found. Future reductions in SO2 emissions are found to not affect this correlation and generally act to increase the sensitivity of IEPOX OA to sulfate, even in extreme cases.

Tau confers drug stability but not cold stability to microtubules in living cells

1994 ◽  
Vol 107 (1) ◽  
pp. 135-143 ◽  
Author(s):  
P.W. Baas ◽  
T.P. Pienkowski ◽  
K.A. Cimbalnik ◽  
K. Toyama ◽  
S. Bakalis ◽  
...  
Keyword(s):  
Sympathetic Neurons ◽  
Drug Stability ◽  
Living Cells ◽  
Microtubule Depolymerization ◽  
Cell Biol ◽  
Cold Stability ◽  
The Stability ◽  
Cultured Sympathetic Neurons ◽  
Very High

We previously defined two classes of microtubule polymer in the axons of cultured sympathetic neurons that differ in their sensitivity to nocodazole by roughly 35-fold (Baas and Black (1990) J. Cell Biol. 111, 495–509). Here we demonstrate that virtually all of the microtubule polymer in these axons, including the drug-labile polymer, is stable to cold. What factors account for the unique stability properties of axonal microtubules? In the present study, we have focused on the role of tau, a microtubule-associated protein that is highly enriched in the axon, in determining the stability of microtubules to nocodazole and/or cold in living cells. We used a baculovirus vector to express very high levels of tau in insect ovarian Sf9 cells. The cells respond by extending processes that contain dense bundles of microtubules (Knops et al. (1991) J. Cell Biol. 114, 725–734). Cells induced to express tau were treated with either cold or 2 micrograms/ml nocodazole for times ranging from 5 minutes to 6 hours. The results with each treatment were very different from one another. Virtually all of the polymer was depolymerized within the first 30 minutes in cold, while little or no microtubule depolymerization was detected even after 6 hours in nocodazole. Based on these results, we conclude that tau is almost certainly a factor in conferring drug stability to axonal microtubules, but that factors other than or in addition to tau are required to confer cold stability.

scholarly journals THE ROLE OF THE PROMOTIONAL VIDEO "WONDERFUL INDONESIA: A VISUAL JOURNEY" ON BRAND IMAGE AND TOURIST VISITING INTEREST TO WAKATOBI

2021 ◽  
Vol 1 (1) ◽  
pp. 48-60
Author(s):  
Herien Natasya Santoso ◽  
Christy Widyawati ◽  
Rizki Adityaji
Keyword(s):  
Significant Influence ◽  
Brand Image ◽  
Tourist Destination ◽  
Indonesian Government ◽  
Natural Beauty ◽  
Promotional Video ◽  
Very High

Wakatobi is a tourist destination that has potentials for remarkable natural beauty. The Indonesian government is also aggressively promoting Wakatobi through the making of the video Wonderful Indonesia: A Visual Journey. However, the tourist visiting rate in Wakatobi is still not very high. Therefore, this study aims to determine the effect of the promotional video on brand image and interest in visiting Wakatobi. This study involved 151 people as samples and the results showed that promotional videos are able to have a positive and significant influence on brand image and tourist visiting interest. Likewise, the brand image is able to provide a positive and significant influence on tourist visiting interest

scholarly journals An unusual aspartic acid cluster in the reovirus attachment fiber σ1 mediates stability at low pH

2021 ◽  
Author(s):  
Giulia Glorani ◽  
Max Ruwolt ◽  
Nicole Holton ◽  
Ursula Neu
Keyword(s):  
Aspartic Acid ◽  
Conformational Changes ◽  
Cell Attachment ◽  
Low Ph ◽  
The Body ◽  
Attachment Protein ◽  
A Value ◽  
Wide Range ◽  
Trimer Formation

ABSTRACTThe reovirus attachment protein σ1 mediates cell attachment and receptor binding and is thought to undergo conformational changes during viral disassembly. σ1 is a trimeric filamentous protein with an α-helical coil-coiled Tail, a triple β-spiral Body, and a globular Head. The Head domain features an unusual and conserved aspartic acid cluster at the trimer interface, which forms the only significant intra-trimer interactions in the Head, and must be protonated to allow trimer formation.Here we show that all domains of σ1 are remarkably thermostable across a wide range of pH, even at the low pH of the stomach. Interestingly, we determine the optimal pH for stability to be between pH 5-6, a value close to the pH of the endosome and of the jejunum. The σ1 Head is stable at acidic and neutral pH, but detrimerizes at basic pH. When Asp345 in the aspartic acid cluster is mutated to asparagine, the σ1 Head loses stability at low pH and is more prone to detrimerize. Overall, the presence of the Body stabilizes the σ1 Head.Our results confirm a role of the aspartic acid cluster as a pH-dependent molecular switch, and highlight its role in enhancing σ1 stability at low pH.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

THE ROLE OF GRASSLAND IN MANAGEMENT

1968 ◽  
pp. 44-49
Author(s):  
B.K. Cameron
Keyword(s):  
Soil Temperature ◽  
Annual Rainfall ◽  
Silt Loam ◽  
Average Annual Rainfall ◽  
Very High ◽  
Wilting Point

THE PROPERTY to be discussed is a mixed sheep and cropping unit, situated ei ht a miles east of Ashburton and midway between the Ra aia and the Ashburton rivers. Average annual rainfall is 27 in., evenly spread, but there is very high summer evaporation and therefore frequent droughts. On average, the soil is below wilting point for 40 to 50 days each summer. Winters are cold with the soil temperature being below 48°F for about four months each year. The soil is a Lismore stony silt loam averaging 9 in. in depth over gravel.

Endangered Butterflies and their Non-Native Host Plants: Examining Shifting Values of Belonging in Restoration

2019 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Robert M. Anderson ◽  
Amy M. Lambert
Keyword(s):  
Ecological Restoration ◽  
Native Species ◽  
Puget Sound ◽  
A Value ◽  
The Social ◽  
Remote Island ◽  
Scientific Truth ◽  
Native Host

The island marble butterfly (Euchloe ausonides insulanus), thought to be extinct throughout the 20th century until re-discovered on a single remote island in Puget Sound in 1998, has become the focus of a concerted protection effort to prevent its extinction. However, efforts to “restore” island marble habitat conflict with efforts to “restore” the prairie ecosystem where it lives, because of the butterfly’s use of a non-native “weedy” host plant. Through a case study of the island marble project, we examine the practice of ecological restoration as the enactment of particular norms that define which species are understood to belong in the place being restored. We contextualize this case study within ongoing debates over the value of “native” species, indicative of deep-seated uncertainties and anxieties about the role of human intervention to alter or manage landscapes and ecosystems, in the time commonly described as the “Anthropocene.” We interpret the question of “what plants and animals belong in a particular place?” as not a question of scientific truth, but a value-laden construct of environmental management in practice, and we argue for deeper reflexivity on the part of environmental scientists and managers about the social values that inform ecological restoration.

Peran kepemilikan institusional, perencanaan pajak dan dewan komisaris asing terhadap nilai perusahaan

2019 ◽  
Vol 8 (2) ◽  
Author(s):  
Anita Ade Rahma ◽  
Lisa Nabawi ◽  
Ronni Andri Wijaya
Keyword(s):  
Significant Influence ◽  
Firm Value ◽  
Stock Exchange ◽  
Investment Decisions ◽  
Total Sample ◽  
Tax Planning ◽  
Purposive Sampling ◽  
Institutional Leadership ◽  
Company Value

The purpose of this study is to analyze the role of institutional leadership, tax planning and foreign board of commissioners on firm value. The population in this study were 615 companies listed on the Indonesia Stock Exchange in 2015-2017. The sample was chosen using purposive sampling to get a total sample of 325 companies with a total of 975 observations of company data. The results of this study indicate that institutional leadership and tax planning have no role in increasing company value. While the foreign board of commissioners showed a significant influence on the value of the company. This proves that there is a need for diversity in the structure of the board that can trigger an increase in the value of the company. In addition, the presence of a foreign board is needed for the progress of the companyKeywords: Investment decisions; funding decisions; dividend policy; company value

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