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Pumice

Pumice is a lightweight, porous volcanic rock formed by the rapid solidification of lava.
It is commonly used as an abrasive, filter, and insulating material due to its unique physical properties.
Pumice is known for its ability to float on water and has a range of scientific and industrial applications, including in construction, water filtration, and as a soil amendment.
Researchers may utilize pumice comparisons to optimize experimental protocols, enhance reproducibility, and achieve more reliable results in their studies.

Most cited protocols related to «Pumice»

1
Fracture Resistance of Dental Veneers
Forty sound freshly extracted mandibular premolars were used in the study. Dental calculus was removed with periodontal curettes and teeth were stored in distilled water at room temperature. The research was approved by the Ethics Committee of the Federal University of Santa Catarina (#850.087, 2014).
Teeth were marked with a millimeter probe 2 mm below the cement-enamel junction to simulate the periodontal ligament.[20 (link)] Then, they were placed in a container with heated utility wax, forming a thin layer of 0.3 mm, and its thickness was verified with an adapted millimeter probe. After that, they were positioned along their long axis in PVC (Polyvinyl Chloride) cylindrical devices and embedded in self-cure acrylic resin, to simulate the alveolar bone. Once the acrylic resin was completely cured, the teeth were removed, leaving an alveolus-like space. A polyether adhesive (Polyether Adhesive, 3M ESPE) was applied over the roots and 15 min was allowed to pass. Then, they were covered with a 0.3 mm layer of a polyether impression material (Impregum Soft, 3M ESPE) to simulate the periodontal ligament. The teeth were then returned to the acrylic resin mold. After 6 min, the polyether excess was removed, completing the periodontal ligament simulation [Figure 1].
Then, the teeth were randomly divided into four groups (n = 10), according to the esthetic veneer restorative technique to be performed. This sample size was determined based on previous studies, which conducted similar investigations and used the same sample size.[22 (link)23 (link)24 (link)] NPR = teeth without dental preparation veneered with resin composite (Amelogen Plus shade A2, Ultradent). The composite resin veneer, with 0.2 mm thick, was extended across the buccal surface and involved 1 mm of the occlusal surface of the buccal cusp; NPC = unprepared teeth veneered with 0.2 mm thick lithium disilicate glass ceramic (IPS e.max Press A1 HT, Ivoclar Vivadent) extended across the buccal surface, involving 1 mm of the occlusal surface of the buccal cusp. P2C = teeth with a 0.2 mm dental preparation on the buccal surface and occlusal reduction of 0.2 mm, veneered with 0.2 mm thick lithium disilicate glass-ceramic (IPS e.max Press, Ivoclar Vivadent). The veneer was extended across the buccal surface and involved 1 mm of the occlusal surface of the buccal cusp; P5C = teeth with 0.5 mm dental preparation on buccal surface, occlusal reduction of 0.5 mm, and veneered with 0.5 mm thick lithium disilicate glass-ceramic (IPS e.max Press, Ivoclar Vivadent). The veneer extended across the buccal surface and involved 1 mm of the occlusal surface of the buccal cusp [Figure 2].
The bonding procedure and the restorative protocol used in the nonprepared group (NPR) are shown in Table 1.
Polyvinyl siloxane (Express XT Putty, 3M ESPE) impressions were taken from the teeth of the P2C and P5C groups to fabricate horizontal and vertical guides to be used in the bur preparations steps, aiming to standardize the preparations' depth.
Tapered diamond burs were used for dental preparation in occlusal and buccal surfaces, according to each group depth, aided by adapted customized-periodontal probe, and verified with a digital caliper [Figure 3]. A high-speed handpiece turbine (~200,000 rpm) (T3 LINE E 200, Dentsply Sirona) was used with constant water refrigeration. Dental preparations finishing steps were performed with fine and extra-fine granulation tapered diamond burs.
Impressions were obtained from all teeth of NPC, P2C, and P5C with a single-step impression technique. A light-body (Express XT, 3M ESPE) and a heavy-body (Express XT Putty, 3M ESPE) polyvinyl siloxane material was used. Then, they were sent to the dental technician to make the lithium disilicate glass-ceramic veneers (IPS e.max Press, Ivoclar Vivadent) according to the manufacturer's instructions.
Glass-ceramic veneers were tried in teeth of NPC, P2C, and P5C groups. In all these groups, teeth were cleaned with pumice paste and a rubber cup. All luting procedures were performed by the same operator (LAL) using the following protocol.
The ceramic veneers were etched with 9.6% hydrofluoric acid for 20 s, then, rinsed with water for 30 s, air-dried, and ultrasonically cleaned with distilled water for 5 min. A silane-coupling agent (Silane Primer, Kerr) was applied in the internal surface of the ceramic and remained for 60 s [Figure 4]. Buccal and occlusal dental areas were acid-etched with 37.5% phosphoric acid (Gel Etchant, Kerr) for 30 s, rinsed with air–water spray, and gently air-dried. Once the dental surface was acid-etched, a light-cure adhesive system (OptiBond FL Adhesive, Kerr) was applied with a disposable applicator, and it was not light-cured at this step. In cases where it was possible to identify the presence of exposed dentin in the cervical dental preparation area, by a visible contrast compared to white-opaque acid-etched enamel aspect, a hydrophilic primer (OptiBond FL Primer, Kerr) was applied with a disposable applicator over dentin with gentle movements for 15 s and air-dried during 5 s. Next, hydrophobic adhesive resin (OptiBond FL Adhesive, Kerr) was applied with a disposable applicator for 15 s, creating a thin layer and then gently air-dried. When there was not visible exposed dentin, only the hydrophobic adhesive resin (OptiBond FL Adhesive, Kerr) was applied [Figure 5].
A light-cure resin cement (Nexus 3 Light-Cure, Kerr) was applied in the inner surface of the ceramic veneer. The ceramic veneer was placed with light finger pressure onto the dental area; the resin cement excesses were removed with an angled dental probe parallel to the restoration margin and light-cured with a LED unit (Translux Power Blue, Heraeus Kulzer) with a light intensity of 550 mW/cm2 within occlusal and buccal surfaces for 60 s each surface. The polishing procedure was carried out after 24 h using a sequence of abrasive rubber points (Astropol, Ivoclar Vivadent) [Figure 6].
An aging process was performed by thermocycling procedure. It consisted of 10,000 cycles of water baths, with a temperature variation from 5°C to 55°C and a dwell time of 30 s on each bath.[25 (link)] Then, samples were fixed in a universal testing machine (Instron 4444, Instron Corporation) and subjected to the fracture resistance test under compression force. The test was performed with a speed of 0.5 mm/min using a 2 kN maximum load perpendicular to the buccal surface of direct or indirect veneers, until a complete or partial fracture of the samples. The force was applied through a composite resin (Filtek Z100, 3M ESPE) sphere device with 7 mm diameter [26 (link)] adapted in the universal testing machine to simulate an antagonist tooth cusp [Figure 7]. The load at failure, in Newton (N), required to fracture each sample was recorded and subjected to statistical analysis. Data were analyzed with Shapiro–Wilk normality test, one-way ANOVA, and Duncan multicomparison post hoc test (P < 0.05).
After failure, samples were analyzed to determine the mode of failure under ×10 magnification with a magnifier (YC-86C, YPT, Guangdong, China). According to Schmidt et al.,[24 (link)] the failure modes were classified into four types. Type 1: cohesive failure in restorative material (in this type of failure, fractures are restricted to the ceramic and/or in the composite resin veneer, not involving the dental structure); Type 2: mixed failure (adhesive and cohesive in restorative material); Type 3: adhesive failure (failure in the tooth/veneer interface); and Type 4: root fracture [Figure 8].
Linhares L.A., Pottmaier L.F, & Lopes G.C. (2018). Fracture resistance of veneers in premolars. European Journal of Dentistry, 12(2), 191-198.
Publication 2018
2
Evaluating Denture Acrylic Resin Color Stability
Two 3D-printed [DB (DentaBase, LOT # MO/07875, Asiga, Alexandria, NSW, Australia) and D3D (Denture 3D+, LOT # WY032N01, NextDent, AV, Soesterberg, The Netherlands)] and one conventional (QC-20 heat-polymerize, LOT # D64015111, DeguDent GmbH, Hanau, Germany) denture base acrylic resin were evaluated.
The sample size was calculated using G*Power v. 3.1.9.3 freeware (Heinrich-Heine-Universität Düsseldorf, Germany). The effect size of 0.6, power of 0.8, α = .05 and estimated SD of 0.32 required a minimum of eight samples in each group. However, the samples were increased to 10 to accommodate any specimen loss during the experiment.
Forty disk shaped specimens (10 mm diameter and 3 mm thickness) were fabricated from each material. For DB and D3D materials, the digital specimen file (.STL)(Fig. 1A) was imported into a operational standard slicing software (Chitubox All-in-one SLA/DLP/LCD Slicer, Guangdong, China) equipped with the 3D-printer (ST-1600 3D-Printer, Satori Ltd., London, UK). The 3D-printing resin was poured into the printer, and the specimen was printed layer by layer at a thickness of 50 µm at 0° in a pre-determined dimension by Mask Stereolithography (MSLA) technique.24 The obtained specimens were cleaned with isopropanol and post-print cured by immersion in glycerin for an additional 40 min using a post-curing oven (Zirlux, Zahn Dental Labs, Henry Schein, Waltham, MA, USA) to ensure the reaction of remaining monomers.14 For the conventional heat polymerized acrylic resin specimens, the lost wax technique was followed. The prepared wax pattern was processed to PMMA using the flask-press-pack method.7 (link) Following deflasking, the redundant resin from all the specimen surface was trimmed using a tungsten carbide bur.
For the purpose of standardization, the specimens were handled by a single investigator for finishing and polishing. The specimens were finished with sequential use of silicon carbide paper (Dentaurum, Ispringen, Germany) at 300 rpm under water cooling. Polishing was accomplished using water and pumice slurry in a polishing unit (Derotor, London, England) for 90 s. The specimens' dimensions to the nearest ± 0.05 mm were confirmed using a digital caliper (Digimatic Micrometer, Mitutoyo, Kanagawa, Japan). The specimens were cleaned ultrasonically in distilled water for 5 min and dried with tissue paper before baseline color measurements (T0).
Following T0, the specimens were thermocycled (TC), subjected to mechanical brushing and later immersed in staining medium corresponding to one year of oral use. The specimens were TC for 10,000 cycles at 5℃ – 55℃, with 30 s dwell time and 10 s transfer time in a thermocycler (Huber 1100, SD Mechatronik GmbH, Feldkirchen-Westerham, Germany) to represent one year of oral use.25 (link) After TC, the specimens were cleaned under running water and stored in distilled water before mechanical brushing simulation.
A simulator device (ZM 3, SD Mechatronik GMBH, Feldkirchen Westerham, Germany) was used to simulate brushing. The specimens were fixed onto the customized plexiglass inside the brushing device's containers using a drop of acrylic monomer. The device was equipped with 12 separate slots to which 12 soft toothbrushes (Colgate® 360®, Colgate-Palmolive Company, Riyadh, Saudi Arabia) were attached. A slurry was then prepared using commercially available dentifrice (Colgate® Regular, Colgate-Palmolive Company, Riyadh, Saudi Arabia) and deionized water at a ratio of 1:1 (by weight) and mixed in a plaster vacuum mixer. All 12 containers were filled with the slurry to cover the specimens (approx. 12 ml/container). Mechanical brushing was accomplished at 356 rpm, under a vertical load of 200 g and a stroke path of 3.8 cm, brushing 12 specimens simultaneously. The total brushing time was 50 min (17,800 cycles) that equalled to one year of tooth brushing.26 (link) The slurry was refilled, and toothbrushes were replaced every 4,500 cycles. The toothbrushes were replaced in accordance with the American Dental Association (ADA) recommendations, which states that brushes be replaced 3 – 4 months or earlier if the toothbrush bristles wear away.27 (link) The specimens were then stored in distilled water for 24 hours before immersion procedure according to the ISO/TR 11405:1994 recommendation.7 (link)
After identification with a bur (Fig. 1B), the specimens were randomly allocated into four groups (n = 10) according to the staining medium used (coffee, lemon juice, coke, and artificial saliva). Coffee (Nescafe Classic, Nestle, Riyadh, Saudi Arabia) and artificial saliva (AS) was prepared fresh. In contrast, lemon juice (Florid's natural lemonade juice, Lake Wales, FL, USA) and coke (The Coca-Cola Company, Riyadh, Saudi Arabia) were used as received from the manufacturer. The coffee beverage was prepared by adding 15 g of coffee powder into 250 mL of boiling water and continuously stirred for 10 min. Once the prepared solution was cooled down to room temperature, it was filtered using a filter paper to remove the residue.28 (link) The AS was prepared by a pharmacist per the description from a previous study.29 (link) The pH of beverages and AS was determined using a benchtop pH meter (pH 2700, OAKTON Instruments, Vernon Hills, IL, USA).
The specimens were then individually immersed in vials containing 20 mL of either of the beverages. Each specimen was suspended inside the vial using dental floss to ensure equal exposure of both surfaces to the beverages. The specimens were immersed in their respective beverages for 288 hours, and the beverages were changed every 24 hours. The immersion time used in this study was equal to one year of oral exposure.30 (link)
The specimens were later removed from the vials, cleaned under running water, and further stored in distilled water for 24 hours. The second color measurements (T1) were recorded, and the specimens were again subjected to the whole procedure (TC + mechanical brushing + immersion) as detailed above to simulate another year of oral use, followed by final color measurements (T2).
Before each color measurement, the specimens were dried well with a disposable paper towel. The color of the specimens were recorded in the 3-dimensional Commission Internationale de l'Eclairege L*a*b* (CIELab) color space using an UV light visible spectrophotometer (LabScan® XE, Hunter Associates Laboratory Inc., Reston, VA, USA). The CIE L*a*b* system is a chromatic value color space measuring both value and chroma on L*a*b* coordinates: L* measures the lightness of the color (a value of 100 corresponds to perfect white and 0 to black); a* measures color in the red (a* > 0) and green (a* < 0) dimension; and b* measures color in the yellow (b* > 0) and blue (b* < 0) dimension.31 (link) The CIE L*a*b* mean reading was repeated three times and the average was calculated for each specimen. The total color alteration (ΔE*) for each specimen at T1 and T2 was calculated using the equation (1) and (2), respectively:


According to the ISO/TR-28642:2016 norm, the CIELAB 50:50% perceptibility threshold (PT) ΔE values is ≤ 1.2, whereas 50:50% acceptability threshold (AT) ΔE value is between 1.2 and 2.7. Any ΔE values above the AT limit is not clinically acceptable.32 Furthermore, in relating the color difference to a clinical situation, the ΔE values were converted to National Bureau of Standards (NBS) units using the equation 3.33 (link)

Data analyses were performed using Statistical Package for Social Sciences v.20.0 (SPSS) (IBM SPSS Inc., Chicago, IL, USA). Shapiro-Wilk test revealed the presence of a normal distribution. Descriptive statistics (mean and SD) were used to describe the quantitative color difference (ΔE). Factorial ANOVA was used to quantify the effect of material type, staining medium, and immersion time on ΔE values. Bonferroni post-hoc test was used for multiple comparisons between independent factors (Materials/staining medium/Time) (α = .05).
Alfouzan A.F., Alotiabi H.M., Labban N., Al-Otaibi H.N., Al Taweel S.M, & AlShehri H.A. (2021). Color stability of 3D-printed denture resins: effect of aging, mechanical brushing and immersion in staining medium. The Journal of Advanced Prosthodontics, 13(3), 160-171.
Publication 2021
3
Lightweight Fiber-Reinforced Concrete Production
During the research, additives-free Portland cement of the PC 500 D0 brand was used, the physical and mechanical characteristics and chemical composition of which are presented in Table 1.
Granite crushed stone was used as a sizeable dense aggregate, and slag pumice was used as a porous one. The physical and mechanical characteristics of a large dense and porous aggregate are presented in Table 2 and Table 3.
Quartz sand was used as a fine aggregate, the physical characteristics of which are presented in Table 4.
For sieves with a mesh size of 2.5, 1.25, 0.63, 0.315 and 0.16, the grain size composition of the sand is given, where the upper line is the partial sieve rest, and the lower line is the full sieve rest.
Glass fiber pretreated with surfactant was used as dispersed reinforcement. Table 5 shows the physical and mechanical characteristics of the fiber used.
Micro silica grade MS-85 was used as a reaction-chemical pozzolanic additive. Table 6 shows the chemical composition of micro silica MS-85.
Polycarboxylate superplasticizer MELFLUX 5581 F manufactured by BASF Construction Additives (Krasnodar, Russia) was used as a plasticizing additive in an amount of 0.3% by weight of cement.
As a control composition, heavy concrete of class B30 was designed with the workability of the mixture corresponding to the draft of the cone 1–4 cm [30 ]. The content of coarse aggregate fractions is represented by the following ratio: 60–fraction 10–20 mm; 40–fraction 5–10 mm [31 (link)]. The parameters of the composition of the concrete mixture obtained as a result of calculations are reflected in Table 7.
During the manufacture of lightweight fiber-reinforced concrete, part of the volume of dense aggregate was replaced with the same volume of porous in an amount of 40%. Glass fiber was introduced in the amount of 3% by weight of the cement. The water consumption was adjusted until the required concrete mix mobility was obtained [32 (link)].
Shcherban’ E.M., Stel’makh S.A., Beskopylny A., Mailyan L.R., Meskhi B, & Varavka V. (2021). Nanomodification of Lightweight Fiber Reinforced Concrete with Micro Silica and Its Influence on the Constructive Quality Coefficient. Materials, 14(23), 7347.
Publication 2021
Calculi Cereals chemical composition Dental Cements Fibrosis granite Physical Examination Pulmonary Surfactants pumice Quartz Range of Motion, Articular Reinforcement, Psychological Retinal Cone Silicon Dioxide Water Consumption
4
Ostrich Skull Mechanical Testing Framework
An ostrich skull, frozen with jaws in occlusion (a farmed sub-adult, aged 6-9 months, obtained after slaughter for meat production), was thawed and the jaw adductor muscles were dissected out (for an overview of avian cranial musculature see Holliday & Witmer, 2007 (link)). Ostriches were used due to their large size and the ability to adhere gauges to the surface of the bone, and as they retain patent sutures in some skull regions into adulthood. The M. pseudotemporalis superficialis was isolated, as this muscle provided the largest and most robust attachment site for loading in the experiments. The muscle was then weighed, before immersion in 15% nitric acid, then bisected to measure individual fibre lengths and pennation angle to determine maximum muscle force (after Biewener & Full, 1992 ).
Due to difficulties in loading an ex-vivo skull with accurate muscle loads and orientations, a number of methods have been used. These include directly loading the original (albeit formaldehyde preserved) muscles (Kupczik et al., 2007 (link)), or screwing material into the skull at the site of muscle attachment on which to apply the forces (e.g., Bright & Rayfield, 2011a (link)). This paper attempts a new method to circumvent some issues associated with previous attempts. Two artificial tendons were made using a strand of carbon fibre, resin and fibreglass. The carbon fibre was looped, with the two loose ends being frayed before being sandwiched between two sets of three fibreglass layers (Fig. 1A). The fibreglass layers were all then impregnated with epoxy resin creating artificial ‘tendons’ that were strong, light, and flexible.
The ‘tendons’ were attached to the M. pseudotemporalis superficialis attachment site (delineated by a bony ridge) on the dorsolateral side of the cranium with cyanoacrylate (M-Bond 200; Vishay Micro-Measurements, Basingstoke, UK), before being screwed in place using three 3.5 mm self-tapping screws (Fig. 1B). Therefore, it should be noted that the loadings replicate only one muscle load and are not truly physiological or representative of a bite. This was considered acceptable, given that the aims of the experiment were specimen-specific validation and testing model sensitivity to the effects of the material properties, sutures and rhamphotheca. During dissection, preparation and testing, the skull and rhamphotheca were kept as moist as possible by frequently covering both with a 50:50 mixture of glycerol and water.
Rectangular planar rosette strain gauges (C2A-06-062LR-350; gauge length 1.52 mm, backing 7.04 × 10.41 mm, Vishay Micro-Measurements, Basingstoke, UK) were attached at 13 sites across the skull (Figs. 2 and 3). The gauge sites were prepared by removing any remaining periosteum with pumice powder (GC-5 Pumice powder; Vishay Micro-measurements, Basingstoke, UK) and the site cleaned with 95% ethanol. Gauges were attached to the sites with cyanoacrylate adhesive (M-Bond 200; Vishay Micro-Measurements, Basingstoke, UK). The gauges were then covered with a waterproof silicon rubber coating for protection (3140 RTV Coating; Dow Corning, Midland, MI, USA). Strains from the 13 gauges were connected to an amplifier (5100B; Vishay Micro-Measurements, Basingstoke, UK), recorded, and converted to principal strains and strain orientations using STRAINSMART 4.01 software (Vishay Measurements Group, Basingstoke, UK). Preliminary drift tests were conducted for all gauges before loading and no thermal drift was observed over a 30 s time period.
The cranium was placed upon a specially designed loading rig adapted from a previous study (Bright & Rayfield, 2011a (link)) which supported the cranium bilaterally under the quadrate at the quadrate/articular (QA) joint with two aluminium bars, and at the anteriormost part of the rhamphotheca with a flat block (Fig. 2). Each of the aluminium bars rested between the quadrate articular surfaces and prevented dorsoventral and mediolateral movement of the posterior of the cranium under loading. To prevent anterior motion during loading, a small, flat, thin plate was attached to the end of each bar that contacted the anterior ventral quadrate during the test. Loads were applied by tying 3 mm low-stretch polyester cord (3 mm Magic Speed; LIROS GmbH, Berg, Germany) to the carbon fibre loops using bowline knots at one end, and hanging balances (HCB 50K100; Kern & Sohn GmbH, Balingen, Germany) at the other. The cord was extended over low-friction pulleys (Size 1 upright block, Barton Marine Equipment, Kent, UK) to apply the load approximating the muscle line of action. The hanging balances (precision of 1 N) were attached to rigging screws (6 mm Fork Bottlescrew; Sea Sure, Hampshire, UK) which allowed for manual tightening of the screws to apply tension without twisting.
Due to the limitations of the amplifier, only four gauges could be tested at any time. During the testing, channel 3 on gauge 6 failed, so gauge 6 was discounted from the study, thus recordings were taken from three groups of four gauges (G1-G4, G5-G9, G10-G13). Each gauge was zeroed, and loads of 32 N were applied to each side by tightening the rigging screws simultaneously. These forces were within the limits of an estimated force for the M. pseudotemporalis superficialis calculated from the dissection (muscle body = 4.18 g, average fibre length = 18.4 mm, average pennation angle = 30.2°; using a muscle stress of 0.3 Nmm−2 gave an average force of 44.7 N for each side) and caused cranial deformation, but not so large that fracture may occur under loading. All gauges were measured twice during two complete trials. After each batch of three or four gauges was loaded, the residual load remaining in the hanging balance after unloading was measured: right tendon average = 6.86 N [S.D. = 1.46], left tendon average = 5.71 N [S.D. = 0.488]. These residual loads probably resulted from friction, knot tightening and elasticity in the cord, and may have resulted in slight variations in the actual loading conditions between each trial. Thus, average residual loads were deducted from the initial load, to give average applied loads of 25.1 N on the right tendon, and 26.3 N on the left tendon. The data from each gauge during a trial is an average of 10 recordings per second taken for 60 s over which a static load was applied (a total of 600 readings per gauge).
Cuff A.R., Bright J.A, & Rayfield E.J. (2015). Validation experiments on finite element models of an ostrich (Struthio camelus) cranium. PeerJ, 3, e1294.
Publication 2015
5
Evaluating Enamel Microhardness and Topography of Primary and Permanent Teeth Exposed to Popping Candies
We used sample size of 30 permanent teeth (premolar) and 30 primary teeth which selected based on previous study[15 (link)] that were extracted due to orthodontics. The teeth were examined by a stereomicroscope, and the nonhypoplastic, Nonhypocalcification and nonfractioned teeth were selected. The teeth were washed to remove the blood, saliva, and other debris, and they were then cleaned with slurry of pumice and placed in the physiologic serum until the start of the experiment. Subsequently, the samples were fixed to the acrylic resin so that enamel appears. Then, to create a smooth surface, the outer enamel surface of specimens was ground with sandpaper (600 grit and then 1200 grit). Then, the microhardness of the enamel in all specimens was measured with Vickers hardness tester (MHZ, Koopa Company, Mashhad, Iran) using Vickers diamond indenter with 50 g load for 10 s. For each specimen, three different hardness tests were performed and the mean degree was reported. Subsequently, the groups were divided as follows:

Primary tooth (D)–permanent teeth (P)

Popping chocolate (A)–strawberry popping candy (B)–orange popping candy (C).

These were titles as DA-DB-DC-PA-PB-PC. Each group included 10 teeth.[15 (link)]
All specimens were exposed to a solution containing 5 g of popping chocolate/candy dissolved in 2 mL of saliva twice a day for 5 min in 5 days. After each exposure, specimens were washed into distilled water for 20 s and then immersed in the artificial saliva until the next stage of the test. Artificial saliva was changed daily.[15 (link)] Subsequently, retests were carried out with the Vickers hardness test. For each specimen, hardness was measured in triplicate and the average was reported. Before the start of the experiment, one sample of each group was sent to atomic force microscopy (AFM) (Easyscan2 Flex) to evaluate surface roughness, and topography was prepared. After the experiment, topography was made from the same sample [Figures 2 and 3].
Tabari M., Alaghemand H., Qujeq D, & Mohammadi E. (2017). Effect of Popping Chocolate and Candy on Enamel Microhardness of Primary and Permanent Teeth. Journal of International Society of Preventive & Community Dentistry, 7(6), 370-376.
Publication 2017
Acrylic Resins Bicuspid BLOOD Cacao Candy Deciduous Tooth Dental Enamel Dentition, Adult Diamond Hardness Tests Microscopy, Atomic Force physiology pumice Saliva Saliva, Artificial Serum Strawberries Tooth

Most recents protocols related to «Pumice»

1
Pumice Characterization of Mount Meager Eruption
The Mount Meager volcanic complex is a calc-alkaline stratovolcano complex situated approximately 150 km north of the city of Vancouver, in southwestern British Columbia and belongs to the northernmost extension of the Cascade Volcanic Arc61 (link). The most recent eruption62 (link) of Mount Meager is dated to 2360 BP and produced explosive and effusive dacite volcanic deposits including: pyroclastic fall deposits, pyroclastic flow deposits, and lava63 (link). For this study, large fragments (> 10 cm) of pumice were collected from proximal to medial outcroppings of the 2360 BP pyroclastic fall deposit. Samples were collected from fresh deposits within an area of quarrying operations. Any banded or welded pumice fragments were avoided. These pumice blocks were crushed and sieved using a sieve stack with mesh sizes of 1 mm, 500 μm, 250 μm, 125 μm, 63 μm. Throughout this paper we refer to each grain size fraction by its catching sieve, for example 250 μm input material was caught in the 250 μm mesh, it therefore contains ash fragments >250 μm but <500 μm.
Jones T.J., Shetty A., Chalk C., Dufek J, & Gonnermann H.M. (2024). Identifying rheological regimes within pyroclastic density currents. Nature Communications, 15, 4401.
Publication 2024
2
Randomized Trial of rhPro-UK Treatment
Not available on PMC !
PUMICE is a multicentre, prospective, randomised, openlabel, blinded-endpoint (PROBE) controlled trial. We plan to recruit 100 trial centres in China in the PUMICE trial. Patients will be randomly assigned, in a 1:1 ratio, to receive rhPro-UK or standard medical treatment using centralised simple randomisation. The follow-up duration will be 90 days (online supplemental file 1).
Xiong Y., Hao M., Pan Y., Duan C., Feng X., Li H., Wu N., Wang L., Meng X., Zhao X, & Wang Y. (2024). Rationale and design of ProUrokinase in Mild IsChemic strokE (PUMICE): a multicentre, prospective, randomised, open-label, blinded-endpoint controlled trial. Stroke and vascular neurology.
Publication 2024
3
Broiler Chick Litter Evaluation in Seasonal Trials
The research was carried out in the broiler barn at the Poultry Unit of the Department of Animal Science, Faculty of Agriculture, Gaziosmanpaşa University.
The animal material of the experiment consisted of mixed-sex broiler chicks (Ross 308), which were obtained from a private commercial breeder. On the day of arrival corresponding to the start of the trials, the day-old chicks were weighed to ensure that the average chick weight was similar in the replicate pens. The wing-tagged chicks were distributed to 15 pens of 2 × 2 m in size (5 litter treatments × 3 replicates) according to the study plan. 50 birds with an equivalent of 12.5 birds/m2 were allotted to each replicate pen. There were 150 chicks in each litter treatment, 750 in each trial (summer; 09 July – 19 August and winter; 26 December – 05 February), and a total of 1500 chicks. The number of males and females in each litter treatment replicate pen at the beginning and at the end of the experiment (42 days of age) both in the winter and summer season trials are indicated in Supplementary Table 1.
The litter treatments in each trial involved wood shavings (WS), acidic pumice (AP), and basic pumice (BP), and the mixtures: wood shavings + acidic pumice (WSAP), and wood shavings + basic pumice (WSBP) in a ratio of 1:1. The litter treatments in each trial are shown in Fig. 1.

Experimental litter treatments (A: Wood shavings, B: Acidic pumice stone, C: Basic pumice stone, D: 50% wood shaving + 50% acidic pumice stone, E: 50% wood shaving + 50% basic pumice stone)

The average litter thickness for all litter groups was 5 cm. To prepare mixtures consisting of different litter materials, each replicate pen of 4 m2 was divided into two equal parts. Thereafter, each litter material was laid in the corresponding section until it was 5 cm deep and consequently, mixed thoroughly.
Standard concentrate feeds purchased from a commercial enterprise were used as feed material throughout the trial. Chick starter feed: between 0 and 14 days (d), broiler grower feed: between 15 and 35 d, and broiler finisher feed: between 36 and 42 d. The general composition of the feeds used in the seasonal trials is given in Table 1.

General nutrient composition of feeds used in the summer and winter trials

Nutrient compositionSummerWinter
Chick starter feedBroiler grower feedBroiler finisher feedChick starter feedBroiler grower feedBroiler finisher feed
Crude protein, %222018232118
Crude cellulose, %555444
Crude ash, %999888
Calcium, %1-1.50.8–1.20.9–1.51-1.50.8–1.20.9–1.5
Phosphorus, %0.500.400.400.50.450.40
Lysine, %1.21.11.01.31.11.0
Methionine, %0.60.50.40.60.50.4
Metabolic energy, Kcal/Kg290030503200305031503200
The study barn was naturally ventilated and had tube feeders and automatic hanging drinkers. Electric heaters ensured the heating of the barn. From the first until the final day (42 d) in both trials, the temperature and humidity values inside the barn were recorded per hour using data loggers hanging at the back level of the birds. The weekly ambient temperature and humidity in the two trials per treatment group are shown in Supplementary Tables 2 and 3, respectively.
From the day of the arrival of chicks to the final day of the trials, a photoperiod (light to dark, L:D) of 24 L:0D was ensured.
Duman M., Şekeroğlu A, & Tainika B. (2024). The potential of pumice as a litter material and its influence on growth performance, carcass parameters, litter quality traits, behavior, and welfare in broiler chickens. Tropical Animal Health and Production, 56(4), 130.
Publication 2024
4
Characterizing Hybrid Cement Pore Solution
Table 2 presents the composition of “HB1” hybrid cement [14 (link)], i.e., pumice, PC (CPC30R) as precursors, industrial grate powders of Na2SO4 and calcium hydroxide Ca(OH)2 as alkaline activators, in a molar ratio Na2SO4/Ca(OH)2=1 .
Table 3 presents the composition of the “SS1” supersulfated cement, previously reported [48 (link)].
The hybrid cement “HB1” contains a higher proportion of PC (CPC30R) and lower pumice contents than the “SS1” (Table 2 and Table 3). However, the “HB1” involves Na2SO4 and Ca(OH)2 as alkaline activators, while the “SS1” uses CaO as the alkaline activator and hemihydrate as the sulfatic activator of [13 (link)]. These composition differences promote distinct reactions during the hydration process and thus, originating variations in the chemical composition of the CE concrete pore solutions. It is reported that the alkaline activators, as a part of the “HB1”, react in situ (Equation (1)) forming CaSO4 and NaOH [14 (link)], both activators of the pumice [13 (link)]. Notably, NaOH would contribute to the alkalinity of the concrete pore solution.
Na2SO4+Ca(OH)2→ CaSO4+NaOH
Table 4 compares the chemical oxide composition of hybrid cement “HB1” with those of two previously reported cements, i.e., supersulfated cement “SS1” [13 (link),48 (link)] and PC [49 (link)].
The main oxides of the hybrid cement “HB1” are CaO (29.78%) and SiO2  (43.05%). The CaO content in PC (58.42%) is about two-fold that of “HB1” [49 (link)], while the inverse can be noted regarding SiO2 contents, due to the pumice contribution. Additionally, “HB1” presents greater contents of Al2O3 , K2O , SO3 and Na2O than PC; the last two are attributed to the Na2SO4 used as activator. On the other hand, the SO3 and Na2O contents are different among “HB1” and the supersulfated cement “SS1”, attributable to differences in the type and amounts of activators used.
The cement extract was prepared with the “HB1”cement and ultrapure deionized water (18.2 MΩ cm) in a water/cement ratio = 1. The mixture was stirred and left during 24 h for the cement to react (hydrate) in a closed recipient. The supernatant was then filtered (2.5 µm pore size filter paper, Whatman, Kent, UK); to avoid carbonation the solution was kept in a sealed container. Table 5 presents the chemical composition of the “HB1” CE solution obtained by absorption spectrometry and atomic emission by plasma and ion selective electrode for the free Cl− ions.
The main ions present are Na+ , SO42− , K+ , Ca2+ and OH− . The alkalinity of the hybrid cement (pH = 12.99) is contributed to the high contents of Na+ and K+ ( NaOH and KOH alkaline hydroxides formation), and that of Ca2+ (Ca(OH)2 formation). According to [26 (link)], the solubility of the Ca2+ increases in the presence of SO42− ions and this fact is attributed to the high pH = 12.99 and ionic strength of the pore solution. On the other hand the presence of chloride ions are originated from the pumice [14 (link)].
Bonfil D., Veleva L, & Escalante-Garcia J.I. (2024). Effect of a Hybrid Pumice–Portland Cement Extract on Corrosion Activity of Stainless Steel SS304 and Carbon Mild Steel A36. Materials, 17(10), 2255.
Publication 2024
5
Validating Genetic Expression Prediction
For the purpose of the prediction performance validation, genotype data from GTEx, TCGA and CPTAC (n = 222) were combined. TCGA was integrated with GTEx and CPTAC by only retaining variants common to all data sets. SNPs with missing rate > 5% were excluded. After further overlapping with the genotype data from HKTR, the final genotype dataset contained 6,305,298 autosomal variants that were used for prediction performance validation of the GReX models.
Gene expression from all NIH datasets (GTEx, TCGA, CPTAC, totalling 222 samples), in units of TPM, was normalised by logarithmic transformation, quantile normalisation (using “aroma.light”), and rank-based inverse normal transformation, as described before25 (link). We then used PEER124 (link) to infer 30 hidden factors that describe global sources of variation in the normalised data. Residuals of gene expression were then calculated from the normalised data by adjusting for age, sex, study (GTEx, TCGA, CPTAC), top three genetic principal components and the 30 hidden factors from PEER using linear regression.
We obtained predicted expression for all imputable genes by applying the PUMICE-derived GReX models to our fully independent validation dataset of 222 human kidney tissue samples (from GTEx, TCGA and CPTAC). Predicted expression for each imputable gene was compared to residuals of gene expression across all samples using Pearson’s correlation coefficient. A correlation coefficient of > 0.1 was used as the criterion of a validated model. Predictive performance of PUMICE-derived validated models between the discovery and validation kidney resources were tested using Pearson’s correlation coefficient.
Xu X., Khunsriraksakul C., Eales J.M., Rubin S., Scannali D., Saluja S., Talavera D., Markus H., Wang L., Drzal M., Maan A., Lay A.C., Prestes P.R., Regan J., Diwadkar A.R., Denniff M., Rempega G., Ryszawy J., Król R., Dormer J.P., Szulinska M., Walczak M., Antczak A., Matías-García P.R., Waldenberger M., Woolf A.S., Keavney B., Zukowska-Szczechowska E., Wystrychowski W., Zywiec J., Bogdanski P., Danser A.H., Samani N.J., Guzik T.J., Morris A.P., Liu D.J., Charchar F.J, & Tomaszewski M. (2024). Genetic imputation of kidney transcriptome, proteome and multi-omics illuminates new blood pressure and hypertension targets. Nature Communications, 15, 2359.
Publication 2024

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More about "Pumice"

Pumice is a remarkable volcanic rock with a wide range of applications, from construction to water filtration.
Its unique properties, such as its lightweight, porous structure and ability to float on water, make it a versatile material with numerous scientific and industrial uses.
One of the key features of pumice is its abrasive quality, which makes it a popular choice for use as a polishing and cleaning agent.
This property has also led to its use in products like Transbond XT, a dental adhesive material, and Isomet, a precision sectioning saw used in material science.
In water filtration, pumice's porous nature allows it to effectively remove impurities, making it a valuable component in systems like Transbond Plus Self Etching Primer.
Its ability to float on water also makes it useful in applications such as Isomet 1000, a precision sectioning saw used for cutting and polishing a variety of materials.
Pumice's lightweight and insulating properties make it a popular choice for construction materials, where it can be used to improve thermal and acoustic performance.
It is also used as a soil amendment, as the Sodium hydroxide can help improve soil structure and drainage.
In the dental industry, pumice is used in polishing and cleaning procedures, as seen in products like Filtek Z350 XT and RelyX Unicem.
Its abrasive qualities make it an effective tool for removing stains and plaque from teeth.
Beyond its industrial applications, pumice has also been used in scientific research, where its unique properties can be leveraged to optimize experimental protocols and enhance reproducibility.
Researchers may utilize pumice comparisons, such as those offered by PubCompare.ai's AI-driven tools, to minimize experimental variability and achieve more reliable results.
Overall, pumice is a versatile and fascinating material with a wide range of applications.
Its unique properties continue to be explored and leveraged in fields ranging from construction to dentistry, and its potential for scientific research is yet to be fully realized.