Air-exposed Conditions Research Articles

Effects of L-NAME and air exposure on mitochondrial energetic markers, thyroid hormone receptor/regulator system and stress/ease-responsive receptor expression in the brain/gut axis of zebrafish

As a signal molecule, nitric oxide (NO) has several physiological actions in fish. However, the action of NO on the brain/gut axis, a classic inter-organal axis that bridges the gastrointestinal tract and the CNS, still requires more understanding. The short-term in vivo action of a NO inhibitor, N-omega-nitro-L-arginine methyl ester (L-NAME), on mitochondrial energetic markers and the receptor expression of thyroid hormone (TH) and neuroendocrine hormones involved in stress/ease response was tested in the brain/gut axis of zebrafish exposed to either in non-stressed or air-exposed condition. L-NAME treatment decreased the NO content in brain and gut segments in non-stressed fish but rose upon L-NAME treatment in air-exposed fish that corresponded with the activation of inos, nnos, hif1a and hif1an transcript expressions. The brain/gut segments that showed spatial and differential sensitivity to L-NAME, modified the transcript expression patterns of stress (adra2da, adrb1, nr3c2)- and ease-responsive (htr2b, slc6a4a, mtnr1aa) hormone receptors. The expression pattern of the TH receptor/regulator system (thra, thrb, dio1, dio2, dio3) becomes more active in gut segments than brain segments upon L-NAME challenge in stressed zebrafish. The data provide evidence for a novel role of NO as an integrator of brain/gut axis segments in zebrafish, where the endogenously produced NO in mid-brain/posterior-gut axis aligns together upon air-exposure stress, providing a lead role to the posterior gut that activates and directs the neuroendocrine receptor expressions of stress/ease responsive genes. The data further invites studies exploring the therapeutic potential of L-NAME in this biomedical model to control the brain/gut axis segments.

The impact of drought duration on two Potamogeton species with different growth forms

When facing new climate extremes, aquatic plant communities may experience more frequent or increasing durations of water shortages. Aquatic macrophytes of permanently inundated habitats (true hydrophytes) may lack the physiological or morphological characteristics that protect terrestrial plants from drying out. Aquatic hydrophytes with floating or emergent leaves are expected to be more resilient to droughts than completely submerged plants, as they have morphological characteristics adapted to air-exposed conditions. Therefore, we expected the latter to survive longer periods of air exposure and perform better with increasing drought than a completely submerged growing species. Here, we conducted a microcosm experiment and exposed two Potamogeton species—the completely submerged growing Potamogeton perfoliatus and the areal leaf producing Potamogeton nodosus—to different drought conditions (1, 5, and 15 days). We aimed to detect how two species with different growth strategies cope with and respond to increasing air exposures with waterlogged sediment. Both species showed a resistance to 1–5 days of drought but showed high mortality after 15 days. They displayed significant differences in all measured morphological responses (shoot length, side shoot, and leaf counts), plant chemistry (carbon, nitrogen, and phosphate), and the produced biomass (shoot, root, leaves), and reacted significantly to increasing drought durations. Differences in their resistance were observed based on the mortality rate and morphological responses. To prevent long-term droughts and keep mortality low, we recommend to the water managers to identify areas of risk and increase water levels during dry periods.

Effect of hypoxia and air-breathing restricted on respiratory physiology of air-breathing loach (Paramisgurnus dabryanus).

This aim of this study was to determine the respiratory physiology response in the gill and gut of Paramisgurnus dabryanus under different breathing treatment patterns. The experimental design included the following three conditions: a control group without any stress treatments, an inhibited group with intestinal respiration inhibited, and an air-exposed group with gill respiration inhibited. The results indicated that the total static metabolic rate in the air-exposed group (188.92 ± 13.67 mg h-1 kg-1) was much higher than that of the other group after 7 days, decreased significantly after the first day of recovery (81.64 ± 7.85 mg h-1 kg-1). The air metabolic rate in the air-exposed group increased significantly after 7 days (P < 0.05). There was no significant difference among the groups. Histological observation on the gill and hindgut of P. dabryanus showed that the gill filament area of inhibited group became larger, while the gill structure of air exposed group showed some damage. The number of capillariesin the hindgut mucosal epithelial in air-exposed group showed a rapidly increase (P < 0.05). Likewise, the gas diffusion distance (1.24 ± 0.36 μm) became significantly shorter (P < 0.05). Lactate dehydrogenase activity of gill in the air-exposed group (846.68 ± 88.78 U mg-1 protein) significantly increased after 7 days whereas succinate dehydrogenase (1.02 ± 0.21 U mg-1 protein) and Na+/K+ ATPase (0.57 ± 0.20 U mg-1 protein) activity decreased significantly (P < 0.05). However, there was no significant change in the hindgut. After recovery, there was no significant difference in lactate dehydrogenase, succinate dehydrogenase, and Na+/K+ ATPase activity in the gill or hindgut in groups. P. dabryanus had a high viability in air-exposed condition. When recovery occurred under normoxic conditions, the physical levels of respiration returned back to the normal level quickly.

Effects of Tidal Scenarios on the Methane Emission Dynamics in the Subtropical Tidal Marshes of the Min River Estuary in Southeast China.

In order to accurately estimate the effects of tidal scenarios on the CH4 emission from tidal wetlands, we examined the CH4 effluxes, dissolved CH4 concentrations, and environmental factors (including in situ pH, Eh and electrical conductivity, porewater SO42−, NO3−, and NH4+) during inundation and air-exposure periods in high- and low-tide seasons in the Min River Estuary in southeast China. By applying static and floating chambers, our results showed that the CH4 effluxes during the inundation periods were relatively constant and generally lower than those during the air-exposed periods in both seasons. When compared, the CH4 effluxes during the air-exposed periods were significantly higher in the high-tide season than those in the low-tide season. In contrast, CH4 effluxes during the inundation periods were significantly lower in the high-tide season than those in the low-tide season. During the inundation periods, dissolved CH4 concentrations were inversely proportional to in situ Eh. Under air-exposed conditions, CH4 effluxes were proportional to in situ pH in both seasons, while the dissolved CH4 concentrations were negatively correlated with the porewater SO42− concentrations in both seasons. Our results highlighted that CH4 effluxes were more dynamic between inundation and air-exposure periods compared to low- and high-tide seasons.

Changes in volatile compounds of living Pacific oyster Crassostrea gigas during air-exposed storage

The changes in volatile compounds of living oysters Crassostrea gigas with shells under air-exposed storage for 7 days at 5 and 20 °C were investigated using an electronic nose system and a gas chromatography–mass spectrometer (GC/MS) with headspace solid-phase microextraction (SPME). Principal component analysis of a data matrix obtained from the electronic nose response and sensory evaluation showed deterioration of oyster odor during the storage period. Headspace SPME–GC/MS analysis revealed that 1-penten-3-one decreased to undetectable levels, and volatile carboxylic acids derived from anaerobic end-products and 1-propanol increased during air-exposed storage. The detection of trimethylamine was observed only in living oysters stored at 20 °C. Amounts of 1-penten-3-ol and 1-octen-3-ol showed few changes through the storage periods. These data suggested that most of aldehydes decreased, whereas trimethylamine and volatile carboxylic acids such as propanoic acid accumulated in deteriorated living oysters stored under air-exposed conditions. Consequently, detection of trimethylamine and volatile carboxylic acids would be useful indices for suitable storage conditions of living oysters.

Annual respiration of Japanese mud snail Batillaria attramentaria in an intertidal flat: its impact on ecosystem carbon flows

The Japanese mud snail Batillaria attramentaria, a common gastropod in northeastern Asia, often predominates in isolated or degraded intertidal flat ecosystems in Japan and in other countries where it has invaded as an alien species. To evaluate the effects of B. attramentaria on carbon flow in intertidal flat ecosystems, we estimated the annual respiration of B. attramentaria from field surveys and laboratory experiments. The densities of the snails, as determined at an intertidal flat of the Seto Inland Sea, western Japan, were 235–485 individuals m−2. Temperature and snail size strongly affected their respiration rates, as determined by measuring their CO2 emission rates using an open-flow infrared gas analyzer method. The respiration rates were higher in the submerged condition than in the air-exposed condition. Based on the size structure of the natural population, laboratory experiment results, and environmental factors in the field (temperature and duration of the ebb/flood tide), we estimated the respiration in spring, summer, and autumn, respectively, as 1.9, 2.4, and 4.0 g C m−2. The total amount of carbon mineralized annually by the respiration of B. attramentaria exceeds 10% of that mineralized through sediment respiration. Based on these data and respiration/ingestion ratios in previous reports, we conclude that B. attramentaria has a significant impact on the carbon flows in intertidal flat ecosystems.

Development and characterization of an equine skin-equivalent model.

There is increasing interest in the biological and pathological study of equine skin owing to the high prevalence of cutaneous diseases in horses. However, knowledge of equine skin cell biology and cultures is limited by the low number of in vitro studies in the literature. The objective of the study was to develop and characterize an in vitro equine skin equivalent. Cultures of pure equine keratinocytes and dermal fibroblasts were obtained by enzymatic digestion of skin biopsies. Fibroblasts were embedded into type I collagen matrices to obtain dermal scaffolds, the surface of which was seeded with keratinocytes. The three-dimensional cultures were exposed to the air-liquid interface to enable epidermal stratification. After 14 days in air-exposed conditions, histological analysis showed that keratinocytes underwent differentiation into a multilayered epidermis. Immunohistochemical studies revealed the expression of epidermal cytokeratin in keratinocytes, whereas vimentin was expressed in dermal fibroblasts, as expected in equine skin. Immunostaining of Ki67 showed proliferative keratinocytes in the stratum basale. A continuous basement membrane at the dermo-epidermal junction was also detected immunohistochemically through the expression of its major components (type IV collagen and laminin 5). Ultrastructural analysis by electron microscopy showed desmosomes located among keratinocytes in all layers and hemidesmosomes among the basal keratinocytes and lamina densa. This study reports, for the first time, the development of an in vitro equine skin-equivalent model that resembles equine skin morphologically, immunohistochemically and ultrastructurally.

In vitro development and characterization of canine epidermis on a porcine acellular dermal matrix

The aim of this study was to develop and to characterize a canine skin epidermal model able to form a proper epidermis on a porcine acellular dermal matrix (PADM). In addition, the role of fibroblasts in skin barrier formation was studied by incorporating or omitting canine dermal fibroblasts in the PADM. Canine epidermal composites were developed by seeding keratinocytes onto the surface of PADM that were previously seeded or non-seeded with dermal fibroblasts. After 14 days of culture under air-exposed conditions and in a special growth medium, skin composites were histologically processed and immunohistochemically characterized to determine the expression of cytokeratins and of vimentin and the presence of basement membrane. In all composites, keratinocytes underwent differentiation to a multilayer epidermis with 5-7 viable cell layers. The stratum basalis, stratum spinosum, stratum granulosum and stratum corneum were identified. The expression of cytokeratins was similar to that described in healthy canine epidermis. Laminin and collagen IV immunostaining revealed a homogeneous layer in the epidermal-dermal junction only when the matrix had been seeded by canine dermal fibroblasts. The model may become a simple, useful and cost-effective tool to investigate the biology and pathology of canine epidermis and could partially replace animal testing in several areas of dermatological research.

電子求引性基の架橋構造を持つ&amp;pi;電子系の開発とn型有機電界効果トランジスタへの応用

Development of organic semiconducting materials based on π-conjugated systems for use in organic field-effect transistors (OFETs) has become an active area of research. We have designed and synthesized a series of electronegative units: Carbonyl-bridged bithiazole, dialkyl-substituted naphtho[2,3-c]thiophene-4,9-dione, alkyl-substituted dioxocyclopenta[b]thiophene, and dicyanomethylene-substituted cyclopenta[b]thiophene. The electronegative π-conjugated systems containing these units have been synthesized as potential active materials for air-stable and/or solution-processable n-type OFETs. Electrochemical measurements revealed that the annelation of the electron-withdrawing group contributes both to lowering the lowest unoccupied molecular orbital energy level and to stabilizing the formation of anionic species. Some of compounds are sufficiently soluble to realize the fabrication of their thin films through a solution technique. These electronegative compounds exhibited n-type semiconducting behavior not only in vacuum but also under air-exposed conditions.

Electron-Transporting Oligothiophenes Containing Dicyanomethylene-Substituted Cyclopenta[b]thiophene: Chemical Tuning for Air Stability in OFETs

We have synthesized new electron-transporting oligothiophenes containing dicyanomethylene-substituted cyclopenta[b]thiophene as an active material for the fabrication of solution-processable n-type organic field-effect transistors (OFETs). The influence of the number of dicyanomethylene groups as well as the position of hexyl groups was investigated in detail by performing photophysical and electrochemical measurements. Results revealed that the optical energy gaps and the lowest unoccupied molecular orbital (LUMO) energy levels can be controlled by changing the number of dicyanomethylene groups. In contrast, the position of hexyl groups has little influence on molecular electronic properties. X-ray diffraction and atomic force microscopy measurements revealed that spin-coated thin films of the new compounds had a crystalline structure. OFETs based on these compounds were evaluated in vacuum and air-exposed conditions, and the electron mobility of up to 0.016 cm(2) V(-1) s(-1) was achieved. Furthermore, we demonstrated that the air stability of the OFETs depends on the LUMO energy level of the compounds.

Air‐Stable n‐Type Organic Field‐Effect Transistors Based on Solution‐Processable, Electronegative Oligomers Containing Dicyanomethylene‐Substituted Cyclopenta[b]thiophene

Solution-processable, electronegative, π-conjugated systems containing dicyanomethylene-substituted cyclopenta[b]thiophene were synthesized as potential active materials for air-stable n-type organic field-effect transistors (OFETs). Electrochemical measurements revealed that these compounds exhibited electrochemical stability and that the lowest unoccupied molecular orbital (LUMO) had an energy level less than -4.0 eV. Flash-photolysis time-resolved microwave conductivity (FP-TRMC) measurements were performed, and the value of intradomain electron mobility was determined to be as high as 0.1 cm(2) V(-1) s(-1) . The OFETs were fabricated by spin-coating thin films of the compounds as an active layer. The electron mobility of the OFETs was 3.5×10(-3) cm(2) V(-1) s(-1) in vacuum. Furthermore, electron mobility of the same order of magnitude and stable characteristics were obtained under air-exposed conditions. X-ray diffraction measurements of the spin-coated thin films revealed the difference of molecular arrangements depending on the inner conjugated units. Atomic force microscopy measurements of crystalline-structured films exhibited the formation of grains. The accomplishment of air-stability was attributed to the combined effect of the low-lying LUMO energy level and the molecular arrangements in the solid state, avoiding both the quenching of electron carriers and the intrusion of oxygen and/or moisture.

Vegetative survival of some wall and soil blue-green algae under stress conditions

Lyngbya major (a wall alga), survived throughout year, maximally to >80 % at atmospheric temperature (AT) of 17-36 degrees C and relative humidity (RH) 60-100 % in rainy and spring seasons, but the survival was 43-64 % in winter when AT decreased to 5 degrees C and RH was 65-98 %, and 15-23 % in summer when AT reached 48 degrees C and RH was 23-60 %. All soil algae (Lyngbya birgei, Aphanothece pallida, Gloeocapsa atrata, Oscillatoria subbrevis, O. animalis) survived >90 % in rainy season when soil moisture content (SMC) was 89-100 %. Lowering of SMC to a minimum of 55 % in spring and 39 % in winter led L. birgei, O. subbrevis and O. animalis to survive from 75, 66, and 65 %, respectively, in spring and 12, 14, and 20 % in winter, and A. pallida and G. atrata not at all in both seasons. All soil algae did not survive in summer when SMC was 12-30 %. Myxosarcina burmensis survived only in rainy and spring seasons when pond water temperature (PWT) was 19-25 degrees C and 18-26 degrees C, respectively, and not in winter and summer when PWT was 2-14 degrees C and 25-36 degrees C, respectively. L. major and A. pallida survived almost equally well under both submerged and air-exposed conditions for 15 d but less if submerged for more time than air-exposed on moist soil surface, while L. birgei, G. atrata, O. subbrevis, and O. animalis survived submergence in liquid medium better and longer than air-exposure on moist soil surface. Pond alga M. burmensis survived submergence better than air-exposure, true to its aquatic habitat. All algae survived less and died without forming any resistant cells when exposed to physical and physiological water stress (imposed by growing them on highly agarized media or in salinized liquid media), light stress (at 0, 2 and 10 micromol m(-2) s(-1) light intensity) or following UV shock (0.96-3.84 kJ/m(2)). A. pallida and G. atrata cells did not divide on 8 % agarized solid media, in > or =0.3 mol/L salinized liquid media, and in darkness. The presence of sheath over L. major and L. birgei filament cells and mucilage cover over A. pallida and G. atrata cells protect them against physical desiccation to some extent but not against UV shock.

The effect of the Cr and Mo on the surface accumulation of copper in the electrodeposited Ni–Fe/Cu alloy films

In the present study, the surface chemical and depth profile composition of the electrodeposited Ni–Fe base alloy layers on the Cu substrates were investigated with compositions of the Ni 80–Fe 20 (binary) and Ni 77–Fe 20.7–Cr 1.7–Mo 0.6 (quaternary) deposits. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) results showed the surface accumulation of copper on the surface layers of binary alloy films in the form of Cu 2O. In the quaternary films, addition of Cr and Mo reduced the amount of the Cu accumulation at the surface, while Cu accumulation was enhanced under air-exposed condition for both alloy films. Depth profiles using the secondary ion mass spectroscopy (SIMS) revealed that in the binary layers, the amount of oxide phases of the Ni–Fe was greater than that quaternary deposit. It is concluded that addition of the Cr and Mo impurities reduced the amount of the copper at the surface layers and oxygen inside the quaternary films.

Vegetative survival and reproduction under submerged and air-exposed conditions and vegetative survival as affected by salts, pesticides, and metals in aerial green alga Trentepohlia aurea.

Trentepohlia aurea vegetative cells do not survive submerged conditions for more than 5 months, but can survive air-exposed conditions for more than 1 year. Disintegration and rapid death of algal cells was observed to a higher extent under submerged than air-exposed condition. Under submerged conditions T. aurea did not form any sporangium while prolific formation occurred under air-exposed conditions. Under submerged conditions algal cells formed few-celled, filamentous, cytoplasmic type setae. Vegetative cells were resistant to some extent to various levels of salt (NaCl, < or = 0.8 mol/L), pesticides (DDT, 2,4-D or captan, 2000 ppm) and 'heavy' metals (zinc or nickel, 200 ppm; cobalt, < or = 100 ppm.)

Incorporation of linoleic acid by cultured human keratinocytes

Linoleic acid is required for the formation and maintenance of the epidermal barrier, but most of the current in vitro keratinocyte culture systems are linoleic acid-deficient. The aim of the present study was to examine the efficiency of linoleic acid uptake in human keratinocyte cultures grown under submerged and air-exposed conditions in serum-free medium. The water-insoluble linoleic acid was bound to carrier molecules (cyclodextrin or bovine serum albumin). Comparable results were obtained with home-made and commercially available linoleic acid complexes. In the submerged cultures, the increase of the linoleic acid medium concentration (ranging from 0 to 20 microg/ml) resulted in a gradual increase in the linoleic acid cellular content, which exceeded 1.4 times the value found in native epidermis when the highest concentration of linoleic acid was used. The addition of linoleic acid did not alter the profile of the other epidermal fatty acids, with the exception of oleic acid, which decreased in parallel with the increasing linoleic acid content. While the content of linoleic acid found in phospholipids was similar to that in native epidermis, a large excess of linoleic acid was detected in triglycerides, the synthesis of which was markedly increased in cultures grown submerged in medium containing higher concentrations of linoleic acid. Under air-exposed conditions, the dermal substrate used seemed to be the most limiting factor for efficient linoleic acid supplementation. A low linoleic acid cellular content was detected when an inert filter was used. De-epidermized dermis was found to be the most permeable substrate for linoleic acid complexes. The cellular linoleic acid content increased in a parallel with the increasing linoleic acid concentration (ranging from 4 to 30 microg/ml), but the overall amount incorporated was lower than that in submerged cultures. The content of linoleic acid in the phospholipid and ceramide fractions isolated from reconstructed epidermis grown under air-exposed conditions was close to that of native epidermis, but the triglycerides remained abnormally enriched in linoleic acid, indicating persistence of some anomalies in epidermal lipogenesis in vitro.

Methotrexate induces apoptotic cell death in human keratinocytes.

The mechanism by which low doses of methotrexate act in psoriasis to restore a clinically normal skin is poorly understood. Apoptosis is a programmed cell death activated when cell removal is needed. The purpose of the present work was to examine using an organotypical model of keratinocyte culture, the possibility that low doses of methotrexate can induce apoptosis of keratinocytes. Epidermal explants were cultivated on dead deepidermized dermis under air-exposed conditions. After 10 days, methotrexate (10(-7) M) was added. After a further 5 days, one part of each culture was fixed and submitted to routine histology, DNA nick end labelling (TUNEL) to detect DNA fragmentation (a molecular marker of apoptotic cell death) and immunohistochemical detection of p53 (a protein involved in apoptosis induced by DNA-damaging agents). The other part of each culture was processed for electron microscopy. A significant proportion of keratinocytes (1%) were damaged and exhibited the morphological features of apoptotic cell death. Immunohistochemical overexpression of p53 was detected in the basal layer of the cultures treated with methotrexate. Low doses of methotrexate induce apoptosis. This mode of action could explain the reduction in epidermal hyperplasia during treatment of psoriasis with methotrexate.

Cleaning of GaN surfaces

The work described in this paper is part of a systematic study of surface cleaning and ohmic contact strategies for GaN. The goal of this investigation was to determine the most effective methods of wet chemical and thermal desorption cleaning for the removal of oxygen (O) and carbon (C) prior to metallization. Hydrochloric (HC1) and hydrofluoric (HF) acid-based cleaning treatments were compared, and thermal desorption as a function of temperature was characterized by sequential heating under ultra high vacuum (UHV) conditions. Auger electron spectroscopy (AES) analysis was used to monitor the presence of surface O and C throughout the study. For the removal of surface oxide, HCl-based solutions were found to be most effective; under as-cleaned, air-exposed conditions, HC1:DI H2O (1:1) solution resulted in the lowest levels of residual O and C. However, HF-based solutions resulted in more effective thermal desorption of C from the surfaces. In contrast to the results typically observed in the thermal desorption cleaning of GaAs, complete removal of oxygen and carbon from airexposed GaN surfaces was not seen using vacuum heating alone, even to temperatures where GaN decomposition occurs (>800-900°C). The results of this study indicate that the presence of oxygen and carbon on the GaN surface is persistent even to high temperatures, and that further in-situ cleaning methods must be added to obtain spectroscopically clean GaN surfaces.

Reconstruction of human epidermis on de-epidermized dermis: Expression of differentiation-specific protein markers and lipid composition

Using the Régnier-Pruniéras method for the reconstruction of epidermis in vitro, a multilayered epidermis was obtained with an overall structure resembling that of native human epidermis. Evaluation of the expression and localization of a number of differentiation-specific protein markers revealed that human epidermis reconstructed on de-epidermized dermis shares some common features with hyper-proliferating epidermis, such as the expression of keratin 6, and of involucrin, transglutaminase and filaggrin in suprabasal layers. Analyses of lipid content revealed that the air-exposed keratinocyte cultures reproduce to a high degree the lipids of the native epidermis, with the exception of higher triglyceride and lower glycosphingolipid content and a very low content of linoleic acid. The differences observed in the expression of differentiation-specific protein markers, as well as in the lipid composition, can be most probably attributed to the culture conditions used, since on culturing freshly excised skin under the air-exposed conditions similar deviations from the non-cultured tissue were observed as in the reconstructed epidermis. Using [ 14C]linoleic acid and [ 14C]acetate it was found that the air-exposed human keratinocyte cultures are capable of synthesizing all lipid species that are present in the native tissue. However, some lipid species are synthesized at rates that are different from those in vivo. This may explain the differences observed in the bulk lipid composition between reconstructed epidermis and its in vivo counterpart.

Iron-sepiolite from the Seikan Tunnel, Japan.

A dark-brown scaly material was found in the pilot tunnel of the Seikan Tunnel. Our mineralogical work has clarified that this material consists largely of iron-sepiolite. The structural formula calculated on the basis of 32 oxygens in the half-unit cell of dehydrated sepiolite is as follows. (Si11.49Ti0.03Al0.38Fe3+0.10)12.00(Fe3+1.25Fe2+0.26Mn0.02Mg6.00)7.53O32•Ca0.03Na0.05K0.04 If the Fe ions are treated as being wholly Fe2+, the following formula will be obtained on the basis of O30(OH)4. (Si11.74Ti0.03Al0.23)12.00(Al0.16Fe2+1.65Mn0.02Mg6.13)7.95O30(OH)4•Ca0.03Na0.05K0.04 This modified formula coincides well with the theoretical one in respect to the numbers of octahedral and tetrahedral cations. Therefore it may be suggested that this sepiolite has been formed primarily as a ferrous-sepiolite and then oxidized in the air-exposed condition. In addition, mineralogical data such as X-ray diffraction, thermal analysis, etc., are presented.