Alkaline Fluids Research Articles

Gingival crevicular fluid alkaline phosphate activity during the retention phase of maxillary expansion in prepubertal subjects: A split-mouth longitudinal study.

The aim of this study was to monitor the alveolar bone formation at the tension sites of teeth supporting the appliances for rapid maxillary expansion (RME) during the retention phase according to the local gingival crevicular fluid (GCF) alkaline phosphatase (ALP) activity. This split-mouth prospective study included 23 prepubertal subjects (15 girls, 8 boys; mean age, 9.0 ± 1.4 years) who had a constricted maxillary arch and were undergoing RME. Periodontal parameters, including probing depth, were recorded at 3 and 6 months after RME. Furthermore, the GCF ALP activity was measured at the tension sites of the supporting test teeth (TT) and at the antagonist control teeth (CT) sites. Periodontal parameters were generally similar between the TT and CT sites during the study, with the exception that probing depth underwent a slight increase at the TT sites. At baseline, the GCF ALP activity was similar between the TT and CT sites; however, at both 3 and 6 months, significantly greater enzymatic activity was seen at the TT sites. The overall probing depth changes were not significantly correlated with the corresponding GCF ALP activity changes for either the TT or the CT sites. Alveolar bone formation at the tension sites would last up to 6 months of retention after RME. These results warrant more comprehensive studies to assess whether the GCF ALP activity has potential as a diagnostic tool for bone formation during the retention phase of RME.

Wadeite (K2ZrSi3O9), an alkali-zirconosilicate from the Saima agpaitic rocks in northeastern China: Its origin and response to multi-stage activities of alkaline fluids

The Triassic Saima alkaline complex in the Liaodong Peninsula of northeastern China covers an area of about 20km2 and is dominated by nepheline syenite, with phonolite at its center, and a concealed body of eudialyte-bearing nepheline syenite in the northwest of the complex. The phonolite has similar features to miaskite, while the nepheline syenites are classified in the agpaitic group according to their mineral assemblage, and the alkalinity and aluminum saturation indexes. Zircon is the dominant Zr-bearing mineral in the phonolite, whereas wadeite occurs as the only primary Zr-bearing mineral in the nepheline syenites. The transitional crystallization from zircon to wadeite reveals an increase in alkalis and a high K/Na ratio as the magmas evolved from the volcanic to the intrusive stage. The primary wadeite grains underwent varying degrees of hydrothermal alteration. Overall, the areas of weak, medium, and strong alteration are characterized by the following respective associations: (1) wadeite+secondary catapleiite/gaidonnayite, (2) wadeite+secondary catapleiite/gaidonnayite+zircon, and (3) pseudomorphs after wadeite. The pseudomorphs are widespread and mainly consist of residual wadeite, secondary zircon, catapleiite/gaidonnayite, K-feldspar, calcite, and some Zr-bearing titanite and vesuvianite. All of the secondary zircon grains in the three associations are typically enriched in Ca and Al compared with the primary Ca-free zircons of the phonolite. The progressive alteration of wadeite suggests that the Saima complex underwent multiple episodes of fluid activity during a hydrothermal stage, including an initial Na-metasomatism via alkaline fluids, then stages most likely involving progressively CO2-rich fluids, and an intensive episode involving a mixture of these fluids with externally derived Ca-rich fluids.

Investigation of extractable organic compounds in deep-sea hydrothermal vent fluids along the Mid-Atlantic Ridge

The possibility that deep-sea hydrothermal vents may contain organic compounds produced by abiotic synthesis or by microbial communities living deep beneath the surface has led to numerous studies of the organic composition of vent fluids. Most of these studies have focused on methane and other light hydrocarbons, while the possible occurrence of more complex organic compounds in the fluids has remained largely unstudied. To address this issue, the presence of higher molecular weight organic compounds in deep-sea hydrothermal fluids was assessed at three sites along the Mid-Atlantic Ridge that span a range of temperatures (51 to >360°C), fluid compositions, and host-rock lithologies (mafic to ultramafic). Samples were obtained at several sites within the Lucky Strike, Rainbow, and Lost City hydrothermal fields. Three methods were employed to extract organic compounds for analysis, including liquid:liquid extraction, cold trapping on the walls of a coil of titanium tubing, and pumping fluids through cartridges filled with solid phase extraction (SPE) sorbents. The only samples to consistently yield high amounts of extractable organic compounds were the warm (51–91°C), highly alkaline fluids from Lost City, which contained elevated concentrations of C8, C10, and C12n-alkanoic acids and, in some cases, trithiolane, hexadecanol, squalene, and cholesterol. Collectively, the C8–C12 acids can account for about 15% of the total dissolved organic carbon in the Lost City fluids. The even-carbon-number predominance of the alkanoic acids indicates a biological origin, but it is unclear whether these compounds are derived from microbial activity occurring within the hydrothermal chimney proximal to the site of fluid discharge or are transported from deeper within the system. Hydrothermal fluids from the Lucky Strike and Rainbow fields were characterized by an overall scarcity of extractable dissolved organic compounds. Trace amounts of aromatic hydrocarbons including phenanthrenes and benzothiophene were the only compounds that could be identified as indigenous components of these fluids. Although hydrocarbons and fatty acids were observed in some samples, those compounds were likely derived from particulate matter or biomass entrained during fluid collection. In addition, extracts of some fluid samples from the Rainbow field were found to contain an unresolved complex mixture (UCM) of organic compounds. This UCM shared some characteristics with organic matter extracted from bottom seawater, suggesting that the organic matter observed in these samples might represent seawater-derived compounds that had persisted, albeit with partial alteration, during circulation through the hydrothermal system. While there is considerable evidence that Rainbow and Lost City vent fluids contain methane and other light hydrocarbons produced through abiotic reduction of inorganic carbon, we found no evidence for more complex organic compounds with an abiotic origin in the same fluids.

Comparative Study on Durability of Fly Ash Based Geopolymer Mortars in Sulphuric Acid and Nitric Acid

Geopolymers are a new promising binder manufactured by activation of a solid alumina silicate source material with a highly alkaline activating solution. Every year a huge amount of Fly ash is obtained from thermal power stations which is rich in silica and alumina and hence can be used with an alkaline fluid (mixture of Na2SiO3 and NaOH is used here) as a substitute of Cement. The process of hardening of the paste consists of formation of three dimensional polymeric chain and hydration does not take place in this case. So emission of CO2 is very less in this case. An experimental study was conducted to study and compare the durability or acid resistance of fly ash based geopolymer mortar exposed to Nitric and Sulphuric acid. Compressive strength, weight of specimens and pH of acid solution is recorded at a regular interval. Residual alkalinity is tested at a regular interval by using 1% Phenolphthalein solution. The results are recorded and compared. Results obtained in the present study indicate that Geopolymers are highly resistant to both Sulphuric and Nitric acid.

HOGARTHITE, (Na,K)2CaTi2Si10O26·8H2O, A NEW MEMBER OF THE LEMOYNITE GROUP FROM MONT SAINT-HILAIRE, QUEBEC: CHARACTERIZATION, CRYSTAL-STRUCTURE DETERMINATION, AND ORIGIN

Hogarthite, (Na,K)2CaTi2Si10O26·8H2O, a new mineral of the lemoynite group, was discovered in vugs within metasomatically altered marble xenoliths in the Poudrette quarry, Mont Saint-Hilaire, La-Vallee-du-Richelieu RCM, Monteregie, Quebec, Canada. Crystals are bladed to blocky, average 0.05 × 0.15 × 2 mm in size, and range in color from tan to white to colorless. The mineral develops in dense, radiating crystal aggregates up to 0.5 × 3 mm in size, and is associated with calcite (several generations), quartz, haineaultite, labuntsovite-Mn, lemoynite, chabazite, and gmelinite-Na. Crystals are elongate along [100], flattened on {010} and are bounded by the forms pinacoid {010} (dominant), pinacoid {100} (minor), and pinacoid {001} (minor). The mineral has a white streak, is non-fluorescent under short-, medium-, and long-wave ultraviolet radiation, is translucent, and has a satiny to silky to subvitreous luster. It has a brittle fracture, a perfect {010} cleavage, a hackly to splintery fracture, an estimated hardness of 4, and D calc = 2.40(1) g/cm3. Hogarthite is biaxial (+) with α 1.567(1), β 1.591(1), and γ 1.618(1) with 2 V meas = 87(1)o and 2 V calc = 88(1)o. The optical orientation is X = b , Y ˄ c = 15o (measured in the obtuse angle β), Z = a . A total of 21 analyses, obtained from seven crystals, gave an average (range) of (wt.%): Na2O 2.37 (1.69–2.92), K2O 2.88 (2.61–3.17), CaO 6.00 (5.40–6.31), TiO2 14.44 (13.70–15.83), ZrO2 1.11 (0.48–1.73), Nb2O5 0.78 (0.42–1.24), SiO2 59.27 (57.32–60.64), H2O 14.10 (calc.), total 100.95. The empirical formula (based on 34 anions) is (Na0.78K0.62□0.51Ca0.09)Σ2.00Ca(Ti1.85Zr0.09Nb0.06)Σ2.00Si10.09O26·8H2O, and the simplified formula is (Na,K)2CaTi2Si10O26·8H2O. The presence of (OH) and H2O were confirmed via refinement of the crystal-structure and data from combined FTIR and Raman spectroscopies. The mineral crystallizes in space group C 2/ m with a 10.1839(5), b 15.8244(6), c 9.1327(7) A, β 104.463(2)o, V 1425.1(1) A3, and Z = 2. The strongest six lines on the X-ray powder diffraction pattern [ d in A (I) ( hkl )] are: 8.835 (85) (001), 7.913 (100) (020), 6.849 (70) (![Formula][1] 11), 4.336 (45) (![Formula][2] 31, ![Formula][3] 12), 3.514 (80) (221), 3.426 (55) (![Formula][4] 22, ![Formula][5] 32). The crystal structure, refined to R = 0.049 for 1335 reflections ( F o > 4σ F o), consists of a silicate component, composed of interconnected, non-planar 10-membered rings, arranged into thick slabs and stacked along [001]. These are interleaved with layers of independent TiO6 octahedra, producing a framework of composition [TiSi5O13]2–. Numerous channels within the framework, notably the continuous ones developed by 10-membered silicate rings, are occupied by Na, Ca, and H2O groups. Hogarthite is considered to be a product of late-stage alkaline fluid enriched in SiO2 and TiO2, and forming under conditions of low P at T < 200 oC, possibly through crystallization of a gel. [1]: /embed/mml-math-1.gif [2]: /embed/mml-math-2.gif [3]: /embed/mml-math-3.gif [4]: /embed/mml-math-4.gif [5]: /embed/mml-math-5.gif

Geochemical and Mineralogical Characterizations of Bentonite interacted with Alkaline Fluids generating in Zambales Ophiolite, Northwestern Luzons, Philippines

フィリピン国ルソン島北西部に分布するザンバレスオフィオライトと近接するベントナイト-沸石鉱山Saile鉱山は，オフィオライト中の低温型蛇紋岩作用などにより生成しセメント浸出水とのアナログ性を持つアルカリ地下水が断層活動に伴い上昇してベントナイトと接触していた直接的証拠が見られ，ベントナイト-セメント相互作用のナチュラルアナログサイトとして絶好の環境条件を備えている．この調査地域のアルカリ地下水との相互作用が見られたベントナイトの地球化学的・鉱物化学的特性として，より強い相互作用があった枕状溶岩に近いベントナイトのCr，Ni，軽希土類元素濃度が高いこと，ベントナイトの枕状溶岩との接触界面でCaゼオライト，カリ長石，鉄濃集帯の形成など5 mm程度のアルカリ変質が見られるが，変質鉱物の閉塞作用により，露頭スケールではほとんどベントナイトの変質が進んでいないことが明らかになった．

A leaky membrane and a sodium transporter at life's great divergence.

A leaky membrane and a sodium transporter at life's great divergence.

Improved in vitro digestion stability of (−)-epigallocatechin gallate through nanoliposome encapsulation

(−)-Epigallocatechin gallate (EGCG) is unstable and degraded in near-neutral or alkaline fluids. To overcome its limitation, EGCG nanoliposome (EN) was prepared by an ethanol injection method combined with dynamic high-pressure microfluidization. EN possessed good physicochemical characterizations (high entrapment efficiency=92.1%, small average particle size=71.7nm, low polydispersity index=0.286 and zeta potential=−10.81mv). EN exhibited a relative good sustained release property. Stability of EGCG in simulated intestinal fluid (SIF) was significantly improved by nanoliposome encapsulation. After 1.5h incubating in SIF without or with pancreatin, the residual EGCG of EN was 31.2% and 47.7% respectively, but the residual EGCG in EGCG solution was only 3.4% and 3.5% respectively. The degenerations of in vitro antioxidant activities of EGCG were effectively slowed by nanoliposome encapsulation. This study expects to provide theories and practice guides for further applications of EN.

Geochemical evidence for active tropical serpentinization in the Santa Elena Ophiolite, Costa Rica: An analog of a humid early Earth?

AbstractSerpentinization is a planetary process that has important consequences on geochemical cycles, supporting microbial activity through the formation of H2 and CH4 and having the potential to sequester atmospheric CO2. We present geochemical evidence of active serpentinization in the Santa Elena Ophiolite, Costa Rica which is sustained by peridotites with a degree of serpentinization less than 50% with no evidence of an internal heat source. Average spring water temperatures are 29.1°C. Two hyperalkaline spring systems were discovered, with a spring fluid pH up to 11.18. The fluids are characterized by low Mg (1.0–5.9 mg/L) and K (1.0–5.5 mg/L) and relative high Ca (29–167 mg/L), Na (16–27 mg/L), Cl (26–29 mg/L), hydroxide (41–63 mg/L), and carbonate (31–49 mg/L). Active CH4 (24.3% v/v) vents coupled with carbonate deposits ( ; ) also provide evidence for active serpentinization and carbonation. Isotope ratios of the alkaline fluids (δ18O = −7.9‰, δ2H = −51.4‰) and groundwater (δ18O = −7.6‰; δ2H = −48.0‰) suggests that, during base flow recession, springs are fed by groundwater circulation. Methanogenic Archaea, which comprises a relatively high percentage of the 16S rRNA gene tag sequences, suggests that biological methanogenesis may play a significant role in the system. Santa Elena's extreme varying weather results in a scenario that could be of significant importance for (a) improving the knowledge of conditions on a humid early Earth or Mars that had periodic changes in water supply, (b) revealing new insights on serpentinizing solute transport, and (c) modeling hydrogeochemical responses as a function of recharge.

Study on Compressive Strength of Geopolymer Mortar

India is one of the Developing countries that needs to face the environmental pollution. Have many ways to reduce environmental pollution that causes by production of Portland cement and cause by the increasing of waste material. This paper studies the strength development in geopolymer mortar using industrial by-products. Geopolymer is the term used to represent the binders produced by polymeric reaction of alkaline liquid with silicon and aluminium as source materials. The by-product materials considered in this study are combination of GGBFS and Fly ash. The experimental program involves casting of geopolymer mortar cubes and testing them at 1 day, 3 days and 7 days for compressive strength. Different parameters considered in this study are ratio of sodium hydroxide to sodium meta silicate (1:1 &amp; 1:2 ) and alkaline fluid to binder ratio Keeping 12-Molarity of the alkaline liquid as constant. It can be concluded that the strength increased with an increase in the quantity of GGBFS.

The role of smectite composition on the hyperalkaline alteration of bentonite

Cementitious materials will act as a source of alkaline fluids modifying the mineralogy, pH and physical–chemical properties of bentonite barriers implemented for long-term pollutants retention. A series of reactivity experiments in batch reactors at 175°C were performed for nearly 15months to evaluate the chemical and mineralogical responses of four different bentonites with potential use as buffer barriers against a hyperalkaline K–Na–OH-type solution. This solution simulates the early stage of an ordinary Portland cement leaching in a clay hosted nuclear waste repository. The tested buffer materials were three montmorillonitic bentonites: MX-80 (Wyoming type, USA), FEBEX (Almería, Spain), and a bentonite from Chile (MMT); and a saponitic bentonite from el “Cerro del Águila” (Toledo, Spain). Partial dissolution of smectite and precipitation of secondary phases such as analcime and K-feldspar (sanidine or orthoclase) were found as reaction products in the dioctahedral smectite-based bentonites whereas the trioctahedral character bentonite showed more resistance to alteration. In addition, mixed-layered illite/smectite (I–Sm) interstratification was observed in the four bentonites with different degrees of order. The most heterogeneous octahedral sheet with significant Fe and Mg occupations (FEBEX and MX-80 bentonites) altered to produce R0 random mixed-layered I–Sm (60–40% I), whereas virtually ideal Al–Mg octahedral sheet (MMT bentonite) altered to produce saponite and R≥1 ordered I–Sm (>80% I). The physical–chemical properties (CEC and SSA) were also altered differently in the four bentonites. The methodology used in this work is thought to develop a direct comparison of the performance of potential buffer materials in a nuclear or hazardous waste repository. The evaluation of other basic hydro-mechanical properties should be further evaluated to serve as an indicator of long-term stability of bentonites used in different reactive environments.

Provenance analysis and thermo-dynamic studies of multi-type Holocene duricrusts (1700 BC) in the Sua Salt Pan, NE Botswana

Multi-type duricrusts, composed of silcretes, calcretes, halcretes and sulcretes developed during the Holocene at the northern rim of the Sua Salt Pan, NE Botswana. They were investigated for their light (quartz/chalcedony, feldspar, analcime, clinoptilolite, calcite, kaolinite/halloysite, illite–smectite mixed-layers, halite) and heavy minerals (baryte, clinozoisite–epidote s.s.s., amphibole, corundum, tourmaline, ilmenite, rutile, sphene, kyanite, andalusite, staurolite, garnet, zircon, apatite, monazite, cassiterite, garnet, biotite) using petrographic microscopy, X-ray fluorescence and diffraction analyses, radio-carbon dating, scanning electron microscopy equipped with an EDX-system, cation exchange capacity and infrared spectroscopy. Detrital minerals predominantly derived from the erosion of rocks belonging to the Archaean Basement Complex, the Stormberg Volcanites and the Kalahari sediments. Of particular interest to exploration geologists, geikielite-enriched ilmenite fragments are a hint to kimberlitic pipes. Biodetritus was derived from invertebrates and from vertebrates (fish bones?). A man-made impact on the heavy mineral suite has to be invoked from small fragments of cassiterite fragments that derived from processing of sulfidic and pegmatitic Sn-bearing ore. In the salt-pan-derived duricrusts mainly the aeolian and to a lesser degree fluvial inputs were responsible for the concentration of clasts in these multi-type duricrusts. Moreover, their variegated mineralogy enables us to constrain the physical–chemical regime, prevalently as to the pH and the chemical composition of the major constituents. All duricrusts developed in a self-sufficient chemically closed system where quartz and feldspar provided the elements Si, Na, K, Ca, and Ba to produce the encrustations. The spatial and temporal trend in the Sua Salt Pan rim encrustations may be described as follows: (1) sulcrete–silcretes, (2) silcretes with kaolinite-group minerals towards more recent stages at the rim and smectite-illite mixed-layers and clinoptilolite towards the basin center, (3) calcretes with analcite towards the basin center, (4) halcretes (and soda ash at a more central position). In the sulcrete–silcrete facies the pH decreases from pH 14 down to 4. In the calcretes and halcretes it increases from pH 8 to pH>13. marking a chemical hiatus between stages 1 plus 2 and stages 3 plus 4. Mineral assemblages forming more basinward tend to have derived from more alkaline fluids than those near the edge of the salt pan.

Diagenetic fluid evolution and water-rock interaction model of carbonate cements in sandstone: An example from the reservoir sandstone of the Fourth Member of the Xujiahe Formation of the Xiaoquan-Fenggu area, Sichuan Province, China

Carbonate cement is the most abundant cement type in the Fourth Member of the Xujiahe Formation in the Xiaoquan-Fenggu area of the West Sichuan Depression. Here we use a systematic analysis of carbonate cement petrology, mineralogy, carbon and oxygen isotope ratios and enclosure homogenization temperatures to study the precipitation mechanism, pore fluid evolution, and distribution of different types of carbonate cement in reservoir sand in the study area. Crystalline calcite has relatively heavy carbon and oxygen isotope ratios (δ13C = 2.14‰, δ18O = −5.77‰), and was precipitated early. It was precipitated directly from supersaturated alkaline fluid under normal temperature and pressure conditions. At the time of precipitation, the fluid oxygen isotope ratio was very light, mainly showing the characteristics of a mixed meteoric water-seawater fluid (δ18O = −3‰), which shows that the fluid during precipitation was influenced by both meteoric water and seawater. The calcite cement that fills in the secondary pores has relatively lighter carbon and oxygen isotope ratios (δ13C = −2.36‰, δ18O = −15.68‰). This cement was precipitated late, mainly during the Middle and Late Jurassic. An important material source for this carbonate cement was the feldspar corrosion process that involved organic matter. The Ca2+, Fe3+ and Mg2+ ions released by the clay mineral transformation process were also important source materials. Because of water-rock interactions during the burial process, the oxygen isotope ratio of the fluid significantly increased during precipitation, by about 3‰. The dolomite cements in calcarenaceous sandstone that was precipitated during the Middle Jurassic have heavier carbon and oxygen isotope ratios, which are similar to those of carbonate debris in the sandstone (δ13C = 1.93‰, δ18O = −6.11‰), demonstrating that the two are from the same source that had a heavier oxygen isotope ratio (δ18O of about 2.2‰). The differences in fluid oxygen isotope ratios during cement precipitation reflect the influences of different water-rock interaction systems or different water-rock interaction strengths. This is the main reason why the sandstone containing many rigid particles (lithic quartz sandstone) has a relatively negative carbon isotope ratio and why the precipitation fluid in calcarenaceous sandstone has a relatively heavier oxygen isotope ratio.

English

This case of ours is a 70year old male patient who presented with gastric outlet obstruction. Endoscopy revealed nodular ulcerated mass lesion involving 3/4 th of the circumference noted in the distal body of stomach along the incisura not involving pylorus and was subsequently diagnosed as gastric adenocarcinoma on endoscopic biopsy and for which distal gastrectomy was done. Histopathological sections showed well to moderately differentiated adenocarcinoma of stomach and sections from proximal duodenum showed lobules of brunner glands indicating a rare INTRODUCTION: Brunner's glands (or duodenal glands) are compound tubular submucosal glands found in that portion of the duodenum which is above the hepatopancreatic sphincter (Sphincter of Oddi). Brunner glands are localized predominantly in the submucosa of proximal duodenum that secrete alkaline fluid composed of muc in (MUC-6) which protects duodenal epithelium by counteracting the acid chyme from stomach. 1 Benign duodenal tumors are very rare with an estimated incidence of 0.008% reported in series of 215000 autopsies. 1 Brunner gland hyperplasia first described by swiss physician Johann Conrad brunner. The main function of these glands is to produce a mucus rich alkaline secretion in order to protect the duodenum from the acidic content of chyme (which is introduced into the duodenum from the stomach), provide an alkaline condition for intestinal enzymes, lubrication of intestinal walls and for better absorption. They also secrete urogastrone which inhibits parietal and chief cells of the stomach from

Development of a simple model for the simultaneous degradation of concrete and clay in contact

In nuclear waste repositories concrete and bentonite are used, sometimes in contact with each other. The rate of mutual degradation of concrete and bentonite by alkaline fluids from concrete is explored using a simple model. The model considers dissolution of a soluble compound in the concrete (e.g. portlandite), which is gradually dissolved as the solubilised hydroxide and the cation(s) diffuse towards and into the bentonite in which smectite degrades by interaction with the solutes. Accounting for only the diffusion resistances in concrete and clay, the solubility of the concrete compound and the hydroxide consumption capacity of the smectite, results in a very simple analytical model. The model is tested against several published modelling results that account for reaction kinetics, reactive surface, and equilibrium data for tens to many tens of different secondary minerals. In the models that include several specified minerals often assumptions need to be made on which minerals can form. This introduces subjective assumptions. The degradation rates using the simple model are within the range of results obtained by the complex models. In the studies of the data used in these models it was found that the uncertainties in thermodynamic data are considerable and can give contradictory information on under what conditions smectite degrades. Some smectite models and thermodynamic data suggest that smectite will transform to other minerals spontaneously if there were no kinetic restrictions.

Hypogenic speleogenesis in quartzite: The case of Corona 'e Sa Craba Cave (SW Sardinia, Italy)

The paper presents a detailed study demonstrating the hypogenic origin of the Corona 'e Sa Craba quartzite cave in SW Sardinia (Italy). Although the quartzite host-rock of this cave derived from silicification of Cambrian dolostones and dissolution of carbonate remnants could have had a role in the speleogenesis, detailed morphologic and petrographic investigation revealed clear evidence of quartz dissolution without signs of mechanical erosion by running waters. Thin section microscopy and scanning electron microscope (SEM) images show pervasive dissolution morphologies, such as pits and notches on quartz crystals causing the deep arenization of the cave walls, suggesting that the dissolution of quartz had a primary role in the formation of the void. The study of secondary cave minerals and the sulfur isotopic composition of sulfates and sulfides, coupled with data on fluid inclusions, allowed reconstruction of the peculiar speleogenetic history of this hypogenic hydrothermal quartzite cave. The cave formed by reduced hydrothermal fluids, probably under basic–neutral pH in phreatic conditions. The presence of abundant cations of Ba2+ in reduced Cl-rich fluids enhanced the quartz dissolution rate, allowing the formation of the voids in deep settings. During the Late Oligocene uplift of the area, the hydrothermal fluids in the cave reached oxygen-rich conditions, thus a minerogenetic phase started with the deposition of barite when the temperature of the fluid was ≤50°C. The presence of cinnabar crusts in the lower part of the cave walls and on the boulders suggests a later volcanic phase with Hg-rich vapors ascending from below. Other minerals such as alunite, basaluminite, gypsum and halloysite (typical of an acid sulfate alteration environment), and phosphates were formed in a final, much more recent stage. The δ34S values of the cave sulfate minerals indicate that S is derived from the remobilization of original Precambrian Pb–Zn Mississippi Valley Type ores. These last two stages did not significantly affect the morphology of the cave. The Corona 'e Sa Craba appears to be the world's first example of a hypogenic cave in quartzite where the speleogenetic mechanisms have been studied and reconstructed in detail, using a variety of modern methods. This study confirms that dissolution of quartz by thermal alkaline fluids at depth can produce large dissolutional voids in the apparently poorly soluble quartzite rocks.

Geochemical and mineralogical characterizations of altered bentonite interacted with alkaline fluids, northwestern Luzon, Philippines

Geochemical and mineralogical characterizations of altered bentonite interacted with alkaline fluids, northwestern Luzon, Philippines

Generation of nanoparticles from technical powder of the insecticidal bacterium Bacillus thuringiensis var. kurstaki for improving efficacy

The technical powder of a local isolate of Bacillus thuringiensis (Bt) var. kurstaki namely DOR Bt-1 was subjected to high pressure homogenisation (HPH) to obtain nanoparticles (NPs) ranging 32–1,106 nm as determined through dynamic light scattering. NPs of Bt were also characterised for shape and size through scanning electron microscopy, field emission scanning electron microscopy and transmission electron microscopy that helped in visualising the smallest nanoparticles, i.e., less than even 50 nm. The larger particles comprised mainly Bt spores with a length and width of 1,139 and 813 nm respectively. HPH showed little effect on the spore viability. NPs had a zeta potential above +30 and were stable, resulted in higher mortality of Helicoverpa armigera larvae at a lower dose. Alkali solubilisation of the NPs resulted in higher values of protein and endotoxin quantified through Lowry’s method and ELISA respectively. This is indicative of an increased solubility of the toxin in the midgut alkaline fluid of the insect leading to higher mortality coupled with quicker kill. Thus Bt as NPs has brighter prospects for insect pest management with increased speed of kill at lower doses.

The Effect of Amino-Bisphosphonate Therapy on Gingival Crevicular Fluid Alkaline Phosphatase Activity in Cancer Patients

The enzyme Alkaline Phosphatase (ALP) is considered a biomarker of bone formation and it is used for monitoring intravenous Bisphosphonate (BP) therapy. It can be measured in serum and urine, but also in Gingival Crevicular Fluid (GCF). The aim of the present study was to monitor the GCF-ALP activity fluctuations in cancer patients before and during the first six months of BP therapy, comparing them with systemic serum ALP concentrations. 33 patients and 25 controls were enrolled according to the eligibility criteria. The GCF was collected at baseline, and after every BP administration for 6 times. The total ALP activities were determined spectrophotometrically. The results show how the differences in GCF-ALP activity over time appear to be significant in the BP-taking group (p=0.003), while the differences in serum ALP in the BP-taking group and in GCF-ALP activity in the control group were not significant (p>0.05). GCF-ALP activity may thus represent a possible new biomarker for bone turnover rate evaluation in patients taking intravenous BP therapy. Up to date, this is the first study that investigates on variations of GCF-ALP activity due to changes in bone metabolism caused by intravenous nitrogen-containing BP therapy in cancer patients.

Deposits of minerals of the Kirovograd ore region of the Ukrainian shield: connection with the deep process

Conditions of magmatic rocks complexes and mineral deposits formation of the central part of the Ingul block are determined by existence of two melting sources in the mantle and the crust as well as by the deep permeable «transform» zone - tectonic suture Kherson-Smolensk. Along the deep transform zone supply of the mantle source by melts and fluids is realized and the existence of the crust source provides mixing of earlier melts with new portions added from the mantle. Changing of composition of the deep fluid as well as its transformation in the melts of both sources of melting causes the composition of deposits produced near the surface. Production of quarts gold ore veins is related to water chloride-potassium fluids accompanying formation of palingenetic Kirovograd granites. Increase of fluid alkalinity in the mantle source predetermines activity of the elements which are able to be brought to melt in alkaline environment - titanium and uranium. Gradual dilution of residual crust melts with fluoride-sodium fluid leads to appearance of lithium pegmatite with rare metal mineralization. Accumulation of Li, С s, Ве , Nb et al. is related to changing of distribution coefficients between solid phases and granite melt in presence of fluorine. During the process of Korsun-Novomirgorod pluton and albitite formation, alkalinity of deep fluid increases. In the crustal source its dilution by water takes place that leads to decrease of alkalinity and increase of oxidation potential. Deposition of brannerite and uranium oxides becomes possible.