Spongy Texture Research Articles

Hemangioendothelioma of the spleen and liver in a 1-year-old child.

Concurrent occurrence of hemangioendothelioma in the spleen and liver of a 1-year-old child is a rare clinical case.She had a history of good health. Laboratory tests showed elevated inflammatory markers, but all other parameters were within normal range.In this article, we exhibit the typical clinical presentation and Pathology imaging features of this disease.CT imaging revealed a 9.8 cm×8.6 cm mass in the spleen, with areas of non-enhancing liquefactive necrosis. The mass exhibited heterogeneous enhancement during the arterial phase and progressive enhancement during the venous phase. Multiple nodules were observed in liver segments S2 and S4, the largest being approximately 3.7 cm×3.5 mm, with enhancement patterns similar to the splenic lesion. The patient underwent splenectomy, left hemihepatectomy, and cholecystectomy. Intraoperatively, the splenic mass exhibited some areas appearing spongy. Multiple nodules were observed in the left liver, presenting as gray-brown solid masses with a spongy texture. Pathology confirmed a diagnosis of hemangioendothelioma, supported by positive immunohistochemical staining for CD31, CD34, ERG, and FLI-1.

Evaluating pumice as a sustainable raw material in porcelain tile production: impact on technical properties

AbstractPumice, a porous rock resulting from the rapid cooling of tuff fragments during volcanic activity, exhibits a spongy texture and light color due to its low density. Found predominantly in Central Anatolia and Eastern Anatolia, it has drawn interest for industrial applications. This study delved into utilizing micronized pumice within the porcelain tile manufacturing process. Comparative analyses were conducted between formulations incorporating micronized pumice and the standard ceramic tile recipe. In place of feldspar, micronized pumice was introduced at concentrations of 3%, 5%, and 7%, while clay was substituted with micronized pumice at concentrations of 3%, 5%, 7%, and 10% by weight. The prepared bodies were fired in an industrial kiln at 1210 °C for 54 min, and various physical and mechanical properties were evaluated. These included viscosity, sieve residue, green strength pre-firing, firing shrinkage, water absorption, firing strength, and firing color after-firing. The results indicated that the samples incorporating micronized pumice closely matched the physical and mechanical properties of the standard porcelain tile. Phase and microstructural analyses revealed the presence of mullite and quartz phases. Notably, micronized pumice demonstrated promise as a substitute for clay or feldspar, with the optimal usage rate determined to be 7% in the porcelain tile recipe. This indicates that pumice has the potential to be an alternative raw material in the production of porcelain tiles.

Enhancing mass transfer and preserving heat-sensitive quality of mango through foam mat drying

Mango puree was foamed using hydroxypropyl methylcellulose to achieve foam densities ranging from 0.3 to 0.8 g/cm3. Subsequently, these mango foams were dried at temperatures ranging from 60 to 80 °C. The experimental results showed that mango foam drying was in the falling rate period. The effective moisture diffusivity (D eff ) was well described by the Arrhenius equation, with the pre-exponential factor (D 0) and activation energy (Ea ) closely related to the void area fraction in mango foam. This relationship led to higher D eff and shorter drying times at higher void area fractions. The minimum loss of total phenolics content (TPC) was observed in mango foams with an initial foam density of 0.3 g/cm3 dried at 60ºC, with only a 7% loss. Increasing drying temperatures to reduce drying time did not mitigate TPC loss. Similarly, the minimum reductions in antioxidant activities, as measured by both the 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid and ferric reducing antioxidant power assays, were observed in mango foams with an initial foam density of 0.3 g/cm3 dried at 60 °C, with values of 14% and 18%, respectively. Dried mango foams with lower densities exhibited more pronounced color changes due to the presence of more sponge-like voids. However, the drying temperature did not significantly affect the product color. In addition, dried mango foams with lower initial foam densities displayed a more brittle and spongy texture.

PSVII-22 Effect of Trimming External Fat Before Cooking on Palatability and Calorie Content of Beef Ribeye Steaks

Abstract Consumer concerns about excess dietary fat have increased the practice of removing external fat from beef steaks prior to cooking. This practice, however, may be detrimental to meat eating quality. The objective of this study was to determine the effects of removing the external fat before cooking on the eating quality and calorie content of ribeye steaks. Twenty longissimus thoracis muscles with Canada AAA (n = 10) and AA (n = 10) quality grades (equivalent to USDA Choice and Select, respectively) were obtained from a federally inspected commercial slaughter plant, vacuum packaged and transported under refrigerated conditions to the Lacombe Research and Development Centre (Agriculture and Agri-Food Canada). After an average of 28 d of ageing, the muscles were removed from the vacuum packaging and fabricated into four 2.54-cm steaks. One-half of the steaks were trimmed to 0.635 cm of external fat (cap on). The remaining steaks were completely trimmed of external and seam (kernel) fats (cap off), and the longissimus and spinalis dorsi muscles were combined with butcher’s twine. Steaks were cooked on an electric grill to an endpoint temperature of 74 °C. Subsequently, descriptive sensory analyses were performed by a 10-member trained meat evaluation panel and calorie analyses were conducted. Results: Compared with muscles of AA steaks cooked with cap off, the AA steaks cooked with cap on had longissimus with greater initial and sustained juiciness (P < 0.01) and a tendency towards a smaller proportion of panelists detecting livery off-flavor (P = 0.058) and mealy texture (P = 0.071), and spinalis with a tendency towards fewer panelists detecting unidentified off-flavors (P = 0.096) and spongy texture (P = 0.096). When cooking the AAA steaks with cap on, the longissimus had a decreased frequency of panelists detecting ‘other’ off-flavors (i.e., burnt, rancid, barnyard, stale; P < 0.05) and mushy texture (P < 0.05) and tended to have less off-flavor intensities (P = 0.083), whereas the spinalis had greater beef flavor intensity and desirability (P < 0.05) and fewer panelists tending to detect ‘other’ off-flavors (i.e., burnt, fatty, oily, rancid; P = 0.052), compared with steaks cooked with cap off. The more pronounced flavor effects in the spinalis compared with the longissimus of AAA steaks cooked with cap on could be due to the spinalis having greater endpoint temperatures than the longissimus muscles, which probably caused more Maillard reactions and more efficient fat melting. Regardless of the quality grade and muscle type, cooking steaks with cap on did not increase the calorie content (P > 0.10). Overall, cooking ribeye steaks with external fat had positive effects on juiciness, flavor and texture without increasing the calorie content compared with steaks cooked without external fat. Educating consumers on the benefits of maintaining the external fat while cooking will improve the eating experience of Canadian beef.

Impact of a constant current electrical stimulation (CCES) system and hormonal growth-promoting (HGP) implants on meat quality and palatability of finished steers

This study evaluated the effects of a constant current electrical stimulation (CCES) system and hormonal growth-promoting (HGP) implants on the quality and palatability of the longissimus thoracis et lumborum (LTL) from yearling-finished steers. The experiment used a total of 46 Angus cross steers, which were either non-implanted (n = 20) or implanted with trenbolone acetate and estradiol benzoate (n = 26). The CCES was applied to one side of each carcass during the slaughter process, whereas the other side remained unstimulated. Regardless of the application of HGP implants, the CCES reduced pH at 3 and 72 h post-mortem and shear force at all ageing times (P < 0.05), improved colour at 72 h post-mortem and during the retail display (P < 0.05), increased initial and overall tenderness (P < 0.01), and decreased the amount of perceived connective tissue and the proportion of trained panelists detecting spongy texture (P < 0.05) compared to meat from unstimulated carcass sides. Although CCES increased meat purge losses and reduced moisture content (P < 0.05), this did not affect meat juiciness (P > 0.10). CCES interacted with HGP to prevent increase in drip loss (P > 0.10), increase frequency of panelists detecting bloody/serumy flavour and typical texture, and reduce the proportion of panelists detecting rubbery texture in meat (P < 0.05). Regardless of stimulation treatment, meat from implanted animals had a more pronounced pH decline at 72 h post-mortem (P < 0.05) and a higher proportion of panelists finding no off-flavours (P < 0.05) or bloody/serumy flavour (P < 0.01) than non-implanted cattle. The CCES system tested in this study improved LTL quality and palatability of heavier beef carcasses.

Effect of extrusion on the structural and flavor properties of oat flours

As widely consumed functional grain worldwide, oats have received increasing attention due to numerous health benefits. Compared to the traditional multistep baking methods (saturated steam and kiln drying), extrusion offered economic and practical advantages in time and energy savings, as well as consumer product quality. With the purpose of discovering potentially new products, this study investigated the impact of extrusion on starch structural and flavor profiles (volatile and non-volatile) in oat flour. The high temperature, high pressure, and high shear in the extrusion process changed the intimate texture of the oat flour into irregular, spongy texture, which forms V-type crystal structure. Extruded oat flour's gelatinization temperature was significantly lower than unextruded. Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry demonstrated significant increases in aldehydes and heterocycles after extrusion of oat flours. The odorants in raw oat flours, identified by gas chromatography-olfactometry and odor activity value changed from green to pleasant nutty, grass and bean fragrance in extruded flours. Furthermore, umami amino acid contents increased, while bitter amino acid contents decreased significantly. This study identified the structural and flavor differences in extruded oat flours and provided clues that could improve potential in the development of ready-to-eat cereals and snack foods.

Spongy all-in-liquid materials by in-situ formation of emulsions at oil-water interfaces

Printing a structured network of functionalized droplets in a liquid medium enables engineering collectives of living cells for functional purposes and promises enormous applications in processes ranging from energy storage to tissue engineering. Current approaches are limited to drop-by-drop printing or face limitations in reproducing the sophisticated internal features of a structured material and its interactions with the surrounding media. Here, we report a simple approach for creating stable liquid filaments of silica nanoparticle dispersions and use them as inks to print all-in-liquid materials that consist of a network of droplets. Silica nanoparticles stabilize liquid filaments at Weber numbers two orders of magnitude smaller than previously reported in liquid-liquid systems by rapidly producing a concentrated emulsion zone at the oil-water interface. We experimentally demonstrate the printed aqueous phase is emulsified in-situ; consequently, a 3D structure is achieved with flexible walls consisting of layered emulsions. The tube-like printed features have a spongy texture resembling miniaturized versions of “tube sponges” found in the oceans. A scaling analysis based on the interplay between hydrodynamics and emulsification kinetics reveals that filaments are formed when emulsions are generated and remain at the interface during the printing period. Stabilized filaments are utilized for printing liquid-based fluidic channels.

Additive manufacturing parts made of cobalt-chromium powders synthesized by electroerosion dispersion

Considering the standard procedure for producing globular powder particles, the authors of this paper propose to use the process of electroerosion dispersion for the production of globular particles of certain size for 3D technology. The proposed process is characterized with energy efficiency and sustainability. The waste cobalt-chromium alloy of the TsELLIT grade was used for the purposes of the study. Cobalt-chromium powders were produced by electroerosion dispersion on a special unit designed for conductive materials. Through experiments, it was established that as the particle dispersion rises, the baking process goes faster resulting in enhanced mechanical properties of the final products. Oxides present in fine-grained powders contribute to the intensity of the baking process as they are subject to reduction under heat impact. The spongy texture that forms when the oxides are gone from the metal surface appears to be more active compared with the oxide-film-free surface. The conducted study showed no changes to the structural and phase state of the specimens. Hence, all four specimens retained the following phases: Co, Cr, Ni и Cr3Ni2. The increasing dispersion and specific surface area of the powder leads to decreased porosity and increased microhardness in the final product. Due to the presence of particles of various sizes, the powder layer appears to be denser as cavities and micropores occurring between coarser particles get filled up. This results in lower roughness and higher compression and bend strength in baked parts. This study proves the possibility to control the structure and physico-mechanical properties of additive manufacturing parts made of powders that are obtained from waste cobalt-chromium alloys by electroerosion dispersion. This helps reduce the reliance on imported powders suitable for additive manufacturing while also cutting the cost of the final products.

Effect of incorporation of little millet (Panicum miliare), flaxseed (Linum usitatissimum) and black gram (Vigna mungo) powders on physico-chemical attributes of ready to cook idli mix

Idli is a traditional fermented steamed product having a soft and spongy texture and is widely consumed as a breakfast food item in India. In the present investigation, idli mix was prepared using different combinations of Rawa, Little Millet, Flaxseed Powder and Black Gram. Rawa and Little Millet was added in the ratio of 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90 and 00:100 and 5 percent flaxseed powder was added to each. Physico-chemical analysis shows that with the increase in little millet powder, fat content, ash content, crude fiber content, loose bulk density, packed bulk density and flowability increased. Protein content, carbohydrate content, total solids content and acidity content decreased with increase in the little millet powder. Idli mix powder based on little millet have enhanced nutritional properties as little millet contribute to increased fiber content, increased vitamin and mineral content.

Preparation and some physicochemical properties of freeze-dried vegetables carving

Freeze-drying is a very gentle dehydration method to preserve the highest quality and give the final product a longer shelf-life, based on the principle of removing the ice by sublimation. This research aimed to study freeze-dried manufacturing processes of vegetable carving for application in the foodservice industry. Plant materials used in this study were pumpkin, carrot and Chinese radish which were carved into a rose shape. To prepare, all carved-rose vegetables were dipped in 1.0% CaCl2 solution as a firming agent for 5 mins before freeze-dried operations at the temperature of –50°C under vacuum (~30 Pa) for 50 hrs. Dyeing operation was conducted specifically in carved-rose Chinese radish using pink (0.05 and 0.1%) and red (0.05 and 0.1%) food-grade colour after pretreatment with CaCl2 . The results showed that dried carved-rose vegetables had low water activity (0.32-0.42) and moisture content (8.01-11.44%). The physical properties of freeze-dried pumpkin and carrot carving were firmed and presented a spongy texture with small bubbles spread continuously throughout the piece which helps protect the structural collapse. However, carved-rose radish had a slight shrinkage but it was restored as fresh after immersing in water. Rehydration time was 5 mins for pumpkin and carrot, and 10 mins for Chinese radish which showed remarkable that firm-liked fresh vegetables. Then, freeze-dried vegetables were packed in an aluminum bag filled with nitrogen gas and kept at 25±1°C for 2-months storage. The sensory characteristics evaluated by specialists were ranged in the medium to very like throughout the storage periods. Thus, freeze-dried carved-rose vegetable seems to be very interesting, moreover, conduction on a larger scale for the foodservice industry was particularly noticeable.

Preparation, characterization and biological evaluation of silver nanoparticles and drug loaded composites for wound dressings formed from Lallemantia royleana seeds’ mucilage

After an injury, the wounds need to be covered with a dressing. Lack of absorptive potential and sticking of dressing with the wound causes pain and slows the healing process. The aim of this study was to develop wound dressings having more absorptive potential and less sticking with the wound. The hemicelluloses from Lallemantia royleana seeds possess desirable properties for a wound dressing. The hemicellulose was blended with chitosan/chitin and glutaraldehyde to enhance the absorptive properties of the hemicellulose through cross-linking. Two types of formulations incorporating silver nanoparticles and ciprofloxacin were prepared. The composites were characterized by elemental analysis, Fourier-transform infrared spectroscopy and scanning electron microscopy, and evaluated for their antibacterial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The dressings were subjected to in vivo studies on Albino rats. The dressings were found to be porous and the silver nanoparticles and drug particles were found to be uniformly distributed in the polymeric matrix. The composite containing ciprofloxacin released the drug in a sustained manner for 14–16 days. From extrapolation of the data, it was discovered that the formulation would release around 80% of ciprofloxacin in about two weeks. Silver-ciprofloxacin nano-composites exhibited comparable activity (zone of inhibition 19–30 mm) against E. coli to that of ciprofloxacin (standard, 21–35 mm) and relatively lower activity in case of S. aureus (zone of inhabitation 11–17 mm). The dressings did not stick to the wound site and the site remained wet during the healing process. Thus the use of hemicellulose from L. royleana seeds proved to be beneficial for preparing wound dressings with improved properties because of having high swelling index, porosity and spongy texture.

Electronic Transport Mechanisms Correlated to Structural Properties of a Reduced Graphene Oxide Sponge.

We report morpho-structural properties and charge conduction mechanisms of a foamy “graphene sponge”, having a density as low as ≈0.07 kg/m and a carbon to oxygen ratio C:O ≃ 13:1. The spongy texture analysed by scanning electron microscopy is made of irregularly-shaped millimetres-sized small flakes, containing small crystallites with a typical size of ≃16.3 nm. A defect density as high as ≃2.6 × 10 cm has been estimated by the Raman intensity of D and G peaks, dominating the spectrum from room temperature down to ≃153 K. Despite the high C:O ratio, the graphene sponge exhibits an insulating electrical behavior, with a raise of the resistance value at ≃6 K up to 5 orders of magnitude with respect to the room temperature value. A variable range hopping (VRH) conduction, with a strong 2D character, dominates the charge carriers transport, from 300 K down to 20 K. At T < 20 K, graphene sponge resistance tends to saturate, suggesting a temperature-independent quantum tunnelling. The 2D-VRH conduction originates from structural disorder and is consistent with hopping of charge carriers between defects in the plane, where clusters related to oxygen functional groups act as potential barriers.

Morphological characteristic and Phenetic Relationship of Lysurus periphragmoides Collected from West Java

Lysurus is one of the unique genera in Basidiomycetes. It has a stinky odor and slime on the head. The unusual-shaped makes the species in Lysurus easily to be identified. One of Lysurus had been found in West Java, Indonesia namely L. periphragmoides. The specimen was deposited into Herbarium Bogoriense with code BO 24418. This study aimed to obtain specimens and characterize the Lysurus BO 24418 using morphological characteristics, and analyze the phenetic relationship among Lysurus species. Lysurus BO 24418 has two phases (egg and mushroom). The egg phase is usually hypogeous underground. The mushroom has a head and stem. The head bears the mature spore with slime distribute malodor. The stem has a hollow and spongy texture with a yellowish color. The numerical data of morphological characters of species in Lysurus were analyzed using NTSys ver 2.1 software. Ten characters were used to build a dendrogram using Sequential Agglomerative Hierarchical Nested (SAHN) cluster analysis with Unweighted Pair Group Method with Arithmetic Mean (UPGMA). Phallus indusiatus was selected as an outgroup. The analyses showed the specimen was classified as L. periphragmoides with 100% of similarity coefficient and it was close L. gardneri with 40,4% of similarity coefficient. The characters that cluster among them are stem surface, head type, egg diameter, and spore max length

Modified sorbents based on walnut shell for sorption of toxic gases

In this article, low-cost carbon-based nanoporous materials were synthesized and impregnated in order to offer a sufficient protection for a wide range of toxic chemicals. The microstructure analysis of the samples reveals that the activation promotes the formation of a higher number of small pores and the development of a spongy texture of the sorbents leading thus to an increase in carbon content. The activated samples have apparent micro-mesoporosity confirmed by the corresponding isotherms of low-temperature adsorption of nitrogen. Furthermore, it has been shown that the activation procedure leads to samples with different acidity and this surface property has a marked influence on the performance of the materials. The results of a breakthrough time study for vapors of inorganic and organic substances indicate that the impregnations with Cu and Co are the most suitable for obtaining a universal sorbent. In this regard, an activated carbon impregnated with cobalt that can outperform commercial reference materials intended for this specific application has been developed in this work.

Mikrostrukturna svojstva mortova koji se pripremaju od mješavine živog vapna

The effect of lime characteristics and hot lime mix method on hydraulic, microstructural and mechanical properties of mortars is determined by producing mortars from quicklimes of two different marbles and two limestones. Results of SEM-EDS, XRD and TGA analyses reveal that the porous microstructure of mortars and spongy texture of calcite crystals are the indicators of the hot lime mix method. This study shows that characteristics of limestones used for the production of limes, as well as the preparation method, directly affect hydraulic, mechanical and microstructural properties of mortars.

Depleted lherzolite xenoliths from the leucititic Morrón de Villamayor volcano (Calatrava volcanic field, Spain)

This work reports petrographical, mineralogical and geochemical data of a suite of mantle xenoliths from the Morrón de Villamayor volcanic centre (MVM), which belongs to the Calatrava Volcanic Field (CVF), a part of the Circum-Mediterranean Anorogenic Cenozoic Igneous Province. The MVM volcano is the only centre belonging to the first stage of the CVF magmatism, an ultrapotassic stage that provides a sampling of the subcontinental lithospheric mantle beneath central Spain. The MVM peridotites record a variable host melt interaction (spongy texture and reaction zones), more intense toward xenolith-host leucitite contacts that it was formed during transport within the volcanic melt. The studied mantle xenoliths are spinel lherzolites equilibrated at lower temperatures (618–942 °C) and similar pressure ranges (8.8–13.6 kbar) than other studied CVF mantle xenoliths, and record a lithospheric mantle before the main volcanic Calatrava event. The MVM lherzolites could be classified in two groups by their chondrite-normalized rare earth element (REE) clinopyroxene patterns: group-1 lherzolites show flat pattern, and group-2 lherzolites display a LREE-depleted (N-MORB like) pattern. Group-1 lherzolites represent a more residual lithospheric mantle (up to 9 partial melting %) than group-2 lherzolites (~ 5%), the latter with similar partial melting degrees than other mantle xenoliths from the CVF. Moreover, group-1 lherzolites have undergone a post partial melting refertilization by different metasomatic agents: silicate and alkaline silicate melts different in composition to host leucitite. A primary clinopyroxene concentrate from these MVM lherzolites provides high Sr (87Sr/86Sr = 0.706104) and intermediate Nd (143Nd/144Nd = 0.512830) initial radiogenic ratios, not previously recorded in this volcanic field. This sampling proves the presence of an enriched isotope mantle pole in xenolith suites of the Calatrava area, trending in composition to an intermediate DMM-EMII component.

The effectiveness of ultrasound bath and probe treatments on the quality of baking and shelf life of cupcakes.

Uniform dispersion of emulsion particles of cake batter is very effective on the quality of the final product. A proper aeration process can produce a favorable spongy texture and desirable qualities in the product. Air containment and uniform distribution with smaller particles in the entire texture would be effective in achieving these goals. One of the newest physical methods to accomplish this matter is the use of ultrasound waves. The aim of this study was to investigate the effect of sounding the cake batter using two types of baths and ultrasound probes with two intensities (70% and 100%) over 0, 4, 6, and 8 min on the quality of cake baking and its shelf life. Porosity, cake texture and sensory acceptance, symmetry and uniformity indicator, water activity, and mold and yeast test for cake samples were taken during 14 days of storage in a factorial design. Examining the results showed that the probe ultrasound waves directly affected the quality of the cake, both bath and probe ultrasound types, which were applied for 6 min, improved the desired characteristics, while the increase in sounding time for up to 8 min decreased these parameters.

Large Mucocele in the Labial and Buccal Mucosa

A26-year-old woman presented to the maxillofacial surgery clinic with painless oval shape lesion (Panel A, arrow) arisen from the lower lip and extended to the buccal mucosa. According to the patient, the mass arose after repeated trauma (biting) of the mucosa (Panel B, arrowhead) approximately 3 months ago. Once the patient noted that when she bit the mass, it`s emptied, but then began to grow again. Upon intraoral examination the lesion measured 1 × 1.8 cm in size. Palpation showed its soft and spongy texture. No bluish pattern of the surface was noted. B-mode (Panel C) and power Doppler (Panel D) ultrasound demonstrated cystic, avascular lesion measuring 1.71 × 0.92 cm with echogenic content (asterisk), no signs of echogenic debris, and distinct margins. Acoustic shadowing behind the hyperechogenic vestibular surface of the lower teeth is labeled by circles. The depth of the cropped sonograms is 1.56 cm. Mucocele of the oral cavity (synonyms: oral mucocele, mucous cyst, retention cyst, retention cyst of the minor salivary gland, mucous retention cyst) is a cystic lesion of the minor salivary gland due to its duct alternation/inflammation and subsequent accumulation of saliva. Differential diagnostics of mucocele is usually performed with other similar oral masses: lipomas, lymphangiomas, and hemangiomas. Removal of mucocele includes the excision of mucous cyst associated overlying mucosa, own glandular tissue and other minor salivary glands which are visualized in the wound. Histopathologically, two types of oral mucocele are distinguished: retention and the more often, extravasation variant. Summarizing, despite the majority of mucocele cases presented with mucosa surface color ranged from deep blue to light blue, our case clearly shows a mucocele with a pink color of mucosa above. Recurrence is a complication usually associated with a violation of the operation technique.

Neogene Metasomatism in the Subcontinental Lithosphere beneath SE Asia—Evidence from Modal and Cryptic Phosphorus Enrichment in Peridotites and Pyroxenites from Southern Laos

AbstractMetasomatism is the prime process to create compositional heterogeneity of the upper mantle. Mineralogical and mineral chemical changes of the mantle triggered by metasomatism can be used to deduce the nature of the metasomatic agent(s) and to constrain the timing of metasomatism. This information is vital for an understanding of the secular evolution of a given mantle segment and the magmatic processes occurring therein. For this study spinel-lherzolites and -websterites were collected from ∼16 Myr old alkali-basaltic lava flows that were extruded on the Bolaven Plateau in south–central Laos. These xenoliths are fragments of the shallow continental lithosphere of the SE Asian peninsula and originate from a mantle segment that acted as source for Cenozoic basaltic volcanism in the wake of the India–Asia collision. In both rock types modal metasomatism formed apatite ± whitlockite ± phlogopite ± calcic amphibole ± calcite ± orthopyroxene. The principal metasomatic phase is apatite, which appears in three varieties. Type-I apatite is ±inclusion-free and associated with phlogopite, calcic amphibole, calcite and lamellar orthopyroxene. It is high in Na and low in P and shows low analytical totals indicating a type-B carbonate–apatite component. Type-I apatite presumably precipitated from a P-alkali-rich mixed H2O–CO2 fluid with low large ion lithophile element (LILE)–light rare earth element (LREE) contents. Type-II apatite shows a spongy texture and has lower Na and higher P contents with higher analytical totals. Crosscutting discontinuous zones of type-II characteristics within type-I apatites indicate type-II formation through an exchange Na+ + CO32– = PO43– + Ca2+ by a later fluid with lower aCO2. REE-rich type-III apatite is the youngest type and formed by infiltration of basaltic melts as part of spongy rims around clinopyroxene. One lherzolite contains whitlockite in addition to apatite. Whitlockite formation is ascribed to a short-lived metasomatic event involving a fluid with extremely low aH2O. Disequilibrium between whitlockite and the bulk assemblage is indicated by hydrous silicates in the immediate vicinity of whitlockite and by substantial H2O contents of 250–370 µg g–1 in clinopyroxenes and 170–190 µg g–1 in orthopyroxenes. High-density (1·15–≥1·17 g m–3) CO2–fluid inclusions in the whitlockite-bearing sample provide evidence for the presence of low-aH2O fluids at mantle depths. The spinel-herzolites may also show cryptic metasomatism evidenced by P zoning in olivine, which is characterized by P-poor (&amp;lt;20–130 µg g–1) cores and P-rich (170–507 µg g–1) rims, the latter in part with oscillatory zoning on a µm scale. Element correlations indicate [4]Si4+ + [6](Mg, Fe)2+ = [4]P5+ + [6]Li+, 2 [4]Si4+ + 4 [6](Mg, Fe)2+ = 2 [4]P5+ + 3 [6](Mg, Fe)2+ + [6]vac and/or 5 [4]Si4+ = 4 [4]P5+ + [4]vac as major P incorporation mechanisms. High P–T experiments conducted at 2 GPa and 950–1050 °C yield apatite-saturated P contents of olivine in the range ∼360–470 µg g–1. Most P concentrations in olivines from the xenoliths including those in the P-rich rims, however, are significantly lower than the apatite-saturated values, which indicates disequilibrium uptake of P during growth of the P-rich rims by dissolution–reprecipitation. Diffusion modeling indicates that the P zoning must have formed within decades prior to the eruption of the host basalts. This is consistent with the preservation of Li disequilibrium partitioning between olivine and pyroxenes in some of the xenoliths. All metasomatic phenomena were assigned to two metasomatic events, both of which were in close temporal relation with the eruption of the xenolith host basalts: an older event-1 formed type-I apatite, hydrous silicates, calcite and orthopyroxene and caused the modification of type-I apatite composition towards that of type-II. It is also likely to be responsible for whitlockite formation and P zoning in olivine. A younger event-2 comprises all paragenetic, textural and compositional modifications of the xenolith assemblages associated with the infiltration of basaltic melts.

Deterioration of the cell wall in waterlogged wooden archeological artifacts, 2400 years old

ABSTRACT The relationship between the cell wall ultrastructure of waterlogged wooden archeological artifacts and the state of water bound to cell walls and free in voids is fundamental to develop consolidating and drying technologies. Herein, a lacquer-wooden ware and a boat-coffin dating 4th century BC were selected as representative artifacts to study. Wood anatomy results indicated that they belonged to Idesia sp. and Machilus sp., respectively. They exhibited a typical spongy texture, as revealed by SEM observations, and their water contents had increased significantly. Solid state NMR, Py-GC/MS, imaging FTIR microscopy and 2D-XRD results demonstrated that the deterioration resulted from the partial cleavages of both polysaccharide backbones and cellulose hydrogen-bonding networks, almost complete elimination of acetyl side chains of hemicellulose, the partial depletion of β-O-4 interlinks, as well as oxidation and demethylation/demethoxylation of lignin. These further caused the disoriented arrangement of crystalline cellulose, and the decrease in cellulose crystallite dimensions and crystallinity. In consequence, mesopores and macropores formed, and the number of moisture-adsorbed sites and their accessibility increased. Moreover, results on free water deduced by the changes of pore structure and the maximum monolayer water capacity achieved by the GAB model indicated that water in waterlogged archeological wooden artifacts was mainly free water in mesopores.