Crystalline Deposits Research Articles

Hard Magnetic Properties of Nanocrystalline Cobalt-Phosphorus (Co100-XPX) Electrodeposits

Nanocrystalline cobalt-phosphorus (Co100-xPx) thin films were electrodeposited and their extrinsic magnetic properties were systematically studied by controlling various synthesis parameters. The crystalline thin films exhibited the perpendicular anisotropy which had the behavior of stripe domains. The incorporation of phosphorus (P) atoms into cobalt (Co) lattice structure resulted in the transition from single to pseudo-domain particles. As P content augmented in the crystalline deposits, P precipitation at the grain boundary served as pinning sites, resulting in higher coercivity. Further increase in P content reduced the crystallinity of the deposits and thereby lowered perpendicular anisotropy and coercivity. Promotion of P content was observed at higher NaH2PO2 concentration, lower pH, and smaller film thickness. Temperature was also adjusted to tune P content by controlling the fraction of free Co2+ ions and complexes Co(NH3)x 2+ in solution.

Atypical Corneal Phenotype in Patients With Trachoma and Secondary Amyloidosis.

Purpose:To report clinical presentation, in vivo confocal microscopic features, and corneal phenotype in patients with trachomatous keratopathy (TK) and secondary amyloidosis.Methods:Histopathological records of all patients undergoing keratoplasty at the Dr. Rajendra Prasad Centre for Ophthalmic Sciences over a 3-year period were scanned retrospectively for a diagnosis of TK and amyloidosis. Demographic profile and details of preoperative comprehensive ophthalmic assessment were extracted. The histopathology was freshly reviewed.Results:Fifteen patients (29 eyes) with TK and atypical corneal involvement due to amyloid deposition were identified. Herbert's pits and upper palpebral conjunctival scarring were present in all cases. Central or total diffuse corneal scarring was present involving the anterior stroma in 5 (31%) and the full thickness of the cornea in 11 (69%) of the eyes. Eight (73%) of 11 patients with deep stromal amyloid deposits revealed bilateral, discrete, blue-white opacities at the level of deep stroma and Descemet membrane (DM). Endothelial cells were atrophic and flattened with gutta formation. Confoscans revealed hyperreflective, needle-shaped crystalline deposits of extracellular amyloid at various depths of the corneal stroma up to DM. All host corneal buttons demonstrated Congo red–positive amyloid deposits on histopathological examination.Conclusions:We describe a distinct form of TK unlike the usual presentation of dense, leucomatous, vascularized corneal scarring in trachoma. We believe that amyloid deposits in DM and the corneal endothelium have not previously been reported in patients with trachoma.

Electrodeposition of Zn-rich CuxZn(1−x) Films with Controlled Composition and Morphology

Zn-rich CuxZn(1−x) alloy films (60–88 at% Zn) are grown in a pyrophosphate-based bath via potentiostatic deposition as a precursor for the synthesis of nanoporous Cu. Voltammetric studies show a selective negative shift in the reduction potential of Cu after its complexation with pyrophosphate, allowing for co-reduction of Cu and Zn at similar potential ranges. Anodic stripping characterization reveals a distinct three-stage alloy dissolution behavior that enables the estimation of the alloys’ compositions. Moreover, a systematic study has been done to determine the optimal conditions for Cu–Zn electrodeposition routines at current efficiency of 63%–73% with precise control over the elemental composition and morphology of the alloy. Scanning electron micrographs reveal highly crystalline and uniform alloy deposits, while energy dispersive X-ray spectroscopy results suggest tunability of the alloys’ elemental composition by simple adjustment of the precursor Cu2+:Zn2+ ratio in the deposition bath at the optimized potential of −2.0 V vs MSE. CuxZn(1−x) alloys of similar elemental composition and morphological quality were also electrodeposited on Cu and glassy carbon substrates. Finally, X-ray diffraction patterns of the electrodeposited alloys reveal the presence of CuZn5 and Cu5Zn8 intermetallic compounds that represent brass alloys in the composition range of interest.

Crystallization law of karst water in tunnel drainage system based on DBL theory

Abstract When a tunnel is constructed in a karst area, crystallization of the drainage pipe caused by karst water often threatens the normal operation of the tunnel. This work contributes to this field of research by proposing a functional model based on the diffusion boundary layer (DBL) theory proposed by Dreybrodt in the 1990s. The model is formed by determining the flow rate distribution of the drainage pipe in a laminar flow state and turbulent state, and then by applying Fick’s diffusion law and Skelland’s approximate formula. Then, to further verify the applicability of the functional model, a model test was carried out in the laboratory and the test results are compared to the theoretical results. The results show that the crystallization rate of karst water is mainly affected by the roughness of the pipe wall, followed by the slope of pipes. The slope can affect flow state by controlling the flow rate, which in turn affects the crystallization rate of karst water. When the slope of the drainage pipe is 3, 4, and 5%, the error between the experimental results and the theoretical calculation results is 24.7, 8.07, and 27.9%, respectively, and when the liquid level in the pipe is 7.2, 10.2, and 13.3 mm, the error is 27.9, 9.82, and 2.07%, respectively. Considering that the flow will take away the crystalline deposits on the pipe wall in the experiment, although some results have certain errors, they do not affect the overall regularity.

Modulation of evaporation-affected crystal motion in a drying droplet by saline and surfactant concentrations

Crystallization of evaporating droplets has attracted intense interests thanks to its broad applications in bioengineering, coating technologies and pharmaceutical industries. We investigate the effects of saline and surfactant concentrations on the evaporative dynamics and crystallization patterns of sessile droplets. The droplet exhibits three regimes during evaporation. In regime I, the droplet transits from pinning to depinning, and then the commence of crystallization near the contact line launches regime II, during which the crystal exhibits more or less inward motion. In regime III, the crystal becomes immobilized until the evaporation completes. In the surfactant-free saline droplet, the crystal exhibits a weak gathering motion towards the center at a low saline concentration, resulting in the mild discrete crystalline deposition. Whereas the crystal movability is highly enhanced that they gather as a chunk at a high saline concentration, resulting from the larger droplet contact angle and higher supersaturation at the beginning of crystallization, and the higher liquid-vapor surface tension. These factors increase the horizontal component of the capillary force and solutal Marangoni force which drive crystals inwards. In the presence of surfactant, the crystals stay almost immobilized in regime II compared to the ones of the surfactant-free droplet, leading to discrete crystal morphologies. Surfactant reduces the liquid-vapor surface tension and the contact angle at the beginning of crystallization which are responsible for the smaller inward driving force.

Clinical Features, Prognosis, and Long-Term Response to Ranibizumab of Macular CNVs in Pattern Dystrophies Spectrum: A Pilot Study.

Introduction To analyze the morphological and functional features of choroidal neovascularizations (CNVs) in eyes affected by pattern dystrophies (PD), evaluating their long-term response to intravitreal ranibizumab, and comparing them with CNVs in age-related macular degeneration (AMD). The mean goal is to identify possible disease biomarkers and to evaluate the long-term prognosis of CNVs in PD. Materials and Methods A retrospective study of 42 patients with naïve CNV (26 PD and 16 AMD), for a total of 47 eyes (29 eyes in the PD group and 18 eyes in the AMD group). Each patient received a loading dose of ranibizumab (one monthly for three months) followed by pro re nata (PRN) reinjection protocol for a period of at least three years. Morphological OCT parameters (CRT, central retinal thickness; SRF, subretinal fluid; IRF, intraretinal fluid; SHRM, subretinal hyperreflective material; HRF, hyperreflective foci; HCD, hyperreflective crystalline deposits; cCT, central choroidal thickness; slCT, sublesional choroidal thickness; EZd, ellipsoid zone disruption; and best corrected visual acuity (BCVA in logMAR scale)) were reported at baseline and last follow-up. Results At baseline, no significant differences were found between the two groups, except for choroidal thickness parameters that were significantly greater in the PD group (p = 0.009). Longitudinal PD analysis demonstrated reduction in BCVA (p = 0.009), decrease in CRT (p = 0.046), resolution of SRF in 61.6% of cases (p = 0.004) and SHRM in 30% (p = 0.034), and choroidal thinning both centrally (p = 0.004) and sublesional (p = 0.011) compared to baseline. At 3 years, the PD group received significantly more injections than the AMD (p = 0.011) and showed significantly thicker choroid (p = 0.033) and more frequent HRF (p = 0.006). Regarding the PD group, we found a negative correlation between age and choroidal thicknesses at baseline and at 3 years (p < 0.05); significant positive correlations were found between baseline BCVA and at 3 years (p < 0.001), BCVA at 3 years and IRF (p = 0.003) and SHRM at 3 years (p = 0.003); CRT baseline and CRT 3 years (p = 0.017); HCD at 3 years was associated with greater CRT (p = 0.04) and IRF at 3 years (p = 0.019). Conclusions Early and long-term morphofunctional features of CNVs in PD and in AMD are overlapping. CNVs in PD have poorer long-term response to ranibizumab and higher choroidal thickness suggesting different pathogenetic and evolutionary mechanisms.

Crystalline deposits in the cornea and various areas of the kidney as symptoms of an underlying monoclonal gammopathy: a case report

BackgroundPlasma cell dyscrasias (PCD) are characterized by an abnormal production of intact monoclonal immunoglobulins or parts such as heavy or light chains. In most cases, the monoclonal protein (also termed paraprotein) is produced by a clonal plasma cell population. The production of monoclonal proteins can result in deposits of various types and localization depending on the type, amount, and electrochemical properties of the paraprotein. One histopathologic presentation, albeit rare, are crystalline deposits. They can form in various organs and hence cause a wide spectrum of symptoms.Case presentationA 49-year-old man presented to the emergency department with eyestrain and foreign body sensation after overhead drilling. Examination of the eyes revealed crystalline deposits in the cornea of both eyes. After additional diagnostic testing, deposits were attributed to free light chains. Monoclonal gammopathy of undetermined significance (MGUS) was diagnosed according to serum electrophoresis and immunofixation. Four years later, new onset of proteinuria was detected. A percutaneous biopsy of the kidney showed severe light chain podocytopathy with secondary focal segmental glomerulosclerosis (FSGS) and light chain proximal tubulopathy (LCPT). In these lesions, crystalline deposits identical to the corneal deposits were found in ultrastructural and immunofluorescent analysis. The patient was diagnosed with monoclonal gammopathy of renal significance (MGRS), and a plasma cell directed therapy was initiated.ConclusionsPCD can present with a wide array of symptoms and are notoriously difficult to diagnose. Extrarenal manifestations such as crystalline deposits in the cornea are one possible manifestation. The case presented herein emphasizes the notion that extrarenal paraprotein deposits warrant a thorough search for the underlying clonal disease.

Posterior stromal crystalline keratopathy in gout

A 55-year-old female presented with painless, diminution of vision in the right eye for 6 months. She had episodes of knee pain in the past. Slit lamp bio-microscopy revealed crystal-like deposits in the deeper corneal stroma in the right eye. Anterior segment optical coherence tomography and confocal microscopy revealed crystalline deposits. Systemic work-up revealed tophi in the right great toe with persistently high serum uric acid over the past ranging from 9 to 12 mg%. The patient is on follow-up and currently on medical therapy for gout. Gout may be associated with crystalline deposits in corneal stroma that may cause blurring of vision.

The effect of surface pre-reacted glass-ionomer filler eluate on dental pulp cells and mineral deposition on dentin: In vitro study.

The effects of surface pre-reacted glass-ionomer (S-PRG) filler on pulpal cells and on the composition of dentinal deposits were investigated. Proliferation (CCK-8), cytotoxicity (LDH), and differentiation activity (ALP) tests, along with cell morphology observations, were conducted at 6 and 24h after treatment of pulpal cells with different S-PRG filler eluate concentrations. Dentinal surfaces were immersed in deionized water or S-PRG filler eluate followed by immersion in deionized water or simulated body fluid and observed under scanning electron microscope and elemental analysis using energy dispersive x-ray spectrometer. At 24h, there were significant differences in CCK-8 and ALP activity values between the groups in a concentration-dependent manner. LDH test data were not significantly different among the groups. Cell morphology was not altered at either exposure time. However, decreased cellular density was observed with the highest eluate concentration. Crystalline deposits and occluded dentinal tubules were observed in samples immersed in S-PRG filler with a later immersion in simulated body fluid, which also showed higher concentrations of certain ions compared to surfaces that were not initially treated with S-PRG filler. The lowest two eluate concentrations did not show significant toxicity. S-PRG enhanced the effect of simulated body fluid in the formation of mineral deposits.

Genotype and Long-term Clinical Course of Bietti Crystalline Dystrophy in Korean and Japanese Patients

To investigate the genotype and long-term clinical phenotype of patients with Bietti crystalline dystrophy (BCD) in Korea and Japan. Retrospective case series. We analyzed 62 patients with clinical features of BCD who harbor pathogenic biallelic CYP4V2 variants in their homozygote or compound heterozygote. Data were collected from patient charts, including age, best-corrected visual acuity (BCVA), Goldmann perimetry results, fundus photography, OCT findings, fundus autofluorescence results, and electroretinography findings. We compared the clinical course of the patients with homozygous c.802-8_810de117insGC [exon7del], the most common mutation in the East Asian population, with those of the patients with other genotypes. Best-corrected visual acuity, visual field (VF), and their changes during follow-up. The mean age at the first visit was 55.2 years, with a mean follow-up of 7.1 years. The mean BCVAs at the first and last visits were 0.28 logarithm of the minimum angle of resolution (logMAR) and 0.89 logMAR, respectively. In genetic testing, c.802-8_810de117insGC was detected in 86 of 124 alleles of the patients, and 36 patients were homozygous for this mutation. The age, BCVA, VF area, central foveal thickness, and abnormal hypoautofluorescent area at either the first or last visit were not different between the exon7del homozygotes and the others. The mean BCVA changes per year were 0.089 logMAR in the exon7del homozygotes and 0.089 logMAR in the others. An age- and gender-adjusted linear regression analysis showed no association between the exon7del homozygote status and the rate of vision loss. Characteristic crystalline deposits in the posterior pole were generally observed in younger patients and disappeared over time along with progressive retinochoroidal atrophy. Patients with BCD and a homozygote for c.802-8_810de117insGC accounted for more than 50% of this cohort of Korean and Japanese patients, and the clinical effect of this deleterious variant was not severe in the spectrum of CYP4V2 retinopathy.

Spectral properties of lunar impact melt deposits from Moon Mineralogy Mapper (M3) data

Lunar impact melt deposits have unusual surface properties, unlike any measured terrestrial lava flow. Radar observations suggest that they are incredibly rough at decimeter scales, but they appear smooth in high-resolution, meter-scale optical images. The cause of their unusual surface roughness is unknown. In this work, we investigate the properties of impact melt deposits from seven lunar craters, ranging in size from 7.5 to 96 km in diameter, in an effort to understand the cause of their unique surface texture. We use data from the Lunar Reconnaissance Orbiter's (LRO) Mini-RF instrument to characterize the small-scale roughness of the deposits, data from the LRO Camera (LROC) to characterize their meter-scale morphology, and data from Chandrayaan-1's Moon Mineralogy Mapper (M3) to characterize their composition. This represents the most comprehensive study of the composition of lunar melt deposits completed to date. In particular, we applied a customized spectral unmixing model to the M3 data using laboratory spectra acquired from a range of possible lunar endmembers: pyroxene, olivine, fast-quenched lunar glass simulants, and impact melts and breccias (both synthetic and natural). We found that spectra derived from lunar melt deposits are typically modeled as a mix of the pyroxene and/or impact melts and breccias endmembers. Our modeled results suggest that lunar melt deposits are either crystalline deposits of pyroxene-rich rocks, or a mixture of glassy material and pyroxene minerals. The latter interpretation could explain the roughness observed in the Mini-RF data, if the melt deposits have a glassy surficial layer that shatters during impact gardening to produce decimeter scale blocks.

Graphite Particle in Cornea- An Incidental Finding

An eleven years old female came to Ophthalmology OPD for normal checkup. Her vision was 6/6 in BE's. On Slit Lamp Examination of Anterior Segment, LE Cornea showed crystalline greyish deposits scattered in infero-temporal quadrant mostly suggestive of Pencil Graphite. The rest details were absolutely normal. No entry wound could be made out. The patient and her parents gave no History of any pencil trauma in the past even after. As the particles were inert and patient had no symptom, no active intervention was done (Figures 1 and 2).

Cases of intraocular lens opacification in pseudophakic eyes: analysis of the results of microstructural studies

Relevance. Currently, all over the world, during cataract surgeries, a huge number of intraocular lenses (IOLs) made of different materials are implanted. Alongside with the development of modern IOL materials and designs, publications about their opacities appear. The nature and the localization of IOL opacities mainly depend on the properties of the material out of which the lens is made. Polymethyl methacrylate (PMMA) currently rarely used to manufacture IOLs, tends to cloud in the optical center due to structural breakdown, forming snowflake-like cracks. Opacities of acrylic IOLs depend on the degree of hydrophilic properties of the material. The deposition of crystalline deposits in the optical zone of hydrophilic acrylic lenses leads to a significant decrease in visual acuity and requires IOL explantation. There is a definite dependence of the occurrence of opacities in hydrophilic acryl on the patients concomitant diseases. In hydrophobic acrylic IOLs, vacuoles form, and glistenings occurs. Herewith, visual functions, as a rule, do not suffer.&#x0D; Purpose: to find out what structural changes in the IOL led to the need to remove them from pseudophakic eyes due to a decrease in visual acuity.&#x0D; Materials and methods. Four clouded IOLs made from different materials were examined. The lenses were studied using a SUPRA 55VP scanning electron microscope (Carl Zeiss, Germany) using a secondary electron detector. Element distribution maps on the surface and inside the lenses were collected using an X-max 80 mm2 energy dispersive X-ray analysis detector (Oxford Instruments, UK).&#x0D; Results. A hydrophilic lens with hydrophobic coating became cloudy 5 years after implantation. Hydroxyapatite crystals were found on all parts of the IOL along its surface. In a hydrophobic acrylic IOL, microvacuoles and cavities in the optical center were found using scanning electron microscopy. Two PMMA IOLs underwent self-destruction within 8 years after implantation. Chemical analysis of PMMA lenses did not reveal any inorganic compounds.&#x0D; Conclusion. One of the complications of IOL implantation is an impairment of their transparency. Factors associated with IOL material and manufacturing, as well as the patients comorbidities, can lead to lens opacification at various terms after surgery.

Optic Disc Drusen &amp; a Constellation of Other Features of Retinitis Pigmentosa: A Case Report

<i>Aim: </i>We describe a case of optic disc drusen in retinitis pigmentosa with a myriad of other ocular associations of retinitis pigmentosa coexisting in our patient. To the best of our knowledge, this is the first case reported in a Nigerian. <i>Method: </i>This is a case report of a 16 year old who presented top our eye clinic with a 2 year history of poor night vision with an associated history of difficulty seeing far since childhood. The best corrected visual acuity was 6/18 and 6/12 respectively in the right and left eye. Slit lamp biomicroscopy revealed bilateral grade 1 posterior subcapsular cataracts. Binocular indirect ophthalmoscopy of both eyes revealed vitreous opacities, pale, cupped discs with nasalization of the vessels and yellowish, crystalline deposits at the inferior and superior disc margins. The retina was pale with attenuated vessels, bone spicule pigmentation, atrophic maculopathy and epiretinal membranes bilaterally. <i>Results:</i> An assessment of optic disc drusen, glaucoma, atrophic maculopathy with epiretinal membrane in retinitis pigmentosa was made. The diagnosis of optic disc drusen was confirmed by characteristic ocular B-scan findings. He was commenced on guttae betaxolol BD in both eyes and counselled on the nature of the eye pathology. <i>Conclusion: </i>Optic disc drusen co-exists with retinitis pigmentosa. Though uncommon, optic disc drusen may occur in Africans as seen in our patient. Other ocular associations including myopia, glaucoma and macula lesions like epiretinal membrane and atrophic maculopathy may also be present. The central visual field changes in a patient with retinitis pigmentosa, optic disc drusen and glaucoma may be attributable to all three ocular entities and not just the glaucoma. Prompt diagnosis, follow –up and adequate patient counselling is essential in the management of these patients.

Microscopic and elemental characterization of hydrated dental pulp capping agents.

Context:Characteristics of dental pulp capping agents may influence its interaction with the pulpal cells and can impact the treatment outcome.Aims:This study aims to microscopically characterize various pulp capping agents following hydration.Settings and Design:Original research.Materials and Methods:Disk-shaped specimens of five calcium silicate-based materials, i.e., mineral trioxide aggregate (MTA) Angelus, Biodentine, TheraCal LC, ApaCal ART, and Endocem MTA were prepared. After final set, the materials were immersed in 10 mL of deionized water for 14 days at 37°C. The set materials were characterized by scanning electron microscopy (SEM), X-ray energy dispersive analysis (EDX), and X-ray diffraction (XRD) analysis along with pH analysis of the storage solution using pH meter.Results:On SEM analysis, all the materials showed crystalline deposition on the cement surface with Biodentine exhibiting the most dense and homogenous microstructure. Calcium-silicate-hydrate and calcium hydroxide (CH) were observed as dark-grey and light-grey matrix material, respectively. EDX analysis revealed a high concentration of calcium. The other major elements were oxygen and carbon. The surface calcium concentration in the tested specimens was as follows: Biodentine (42.59 wt.%) > MTA Angelus (38.51wt.%) > Endocem MTA (30.24wt.%) > TheraCal LC (27.51wt.%) > ApaCal ART (22.02wt.%). On XRD analysis, all the materials exhibited peaks for tricalcium silicate and CH, after 14 days of hydration.Conclusions:The higher surface calcium level in Biodentine and MTA Angelus may enhance reparative dentin formation. The surface calcium concentration of Endocem MTA and ApaCal ART was found to be lesser than that of MTA Angelus, but with the added advantage of fast-setting property. Hence, they are potential alternative materials for vital pulp therapy.

Nanometric Deposition of Fluoride Ions on Titanium Alloys and its Influence on In Vitro Bacterial Adhesion and Viability

Bacterial colonization plays a key role on the pathogenesis of peri-implantitis and may be influenced by titanium surface topography. The aim of this in vitro study was to evaluate the influence of titanium topography after fluoride ions deposition in the bacterial colonization. Machined (M), double acid-etched (DE) and double acid-etched surface with fluoride ions deposition (Nano F-) were analyzed by scanning electron microscopy, contact angle and roughness (Ra). Streptococcus mutans viability was quantified by Live/Dead Baclight bacterial viability kit. The mean Ra/contact angle values were 0.20 μm/69.13°, 0.53 μm /92.82° and 0.56 μm/94.33° for M, DE and Nano F-, respectively. M surface presented significantly lower live bacterial counts when compared to the Nano F- surface (p=0.007). The dead bacteria count was higher on the Nano F- surface (p=0.001) than on the M and DE surfaces. Crystalline deposition of fluoride ions (Nano F-) promoted an increase in dead bacteria on the tested titanium surface.

Does gouty nephropathy exist, and is it more common than we think?

Gout is present in one third of subjects with CKD but is usually an exclusion criterion in clinical trials investigating the role of uric acid in kidney disease. Bardin etal. report that one third of gouty subjects have hyperechoic medullas by ultrasound (consistent with crystalline deposits) that correlates with increased risk for hypertension and kidney dysfunction and which were not observed in >500 controls. If validated, a "gouty nephropathy" from microcrystalline deposits could be an important, unrecognized cause of CKD.

Mechanistic Insight into the Relationship between Electrolyte Additives, Solid Electrolyte Interphase Formation, and Lithium Morphology in Lithium Metal Batteries

Directing the morphology of lithium metal deposits during electrodeposition is crucial to the development of safe, high energy density batteries with robust cycle life. Towards this end, mechanistic insight is imperative to understand the relationship between electrolytes, additives, cycling conditions, and the resulting lithium morphologies. In this work we used a standard carbonate-based electrolyte while systematically adding water (0-250 ppm, corresponding to ~0-500 ppm HF) in Li||Cu cells to study the links between electrolyte composition, initial solid electrolyte interphase (SEI) formation, and morphology of electroplated lithium metal. Under conditions in which the electrolyte contains several hundred ppm added HF and applied constant currents on the order of 0.5 mA/cm2, this system yields electrodeposited lithium metal with a highly monodispersed columnar morphology, whereas HF-free electrolytes result in lithium metal with a mossy morphology. We used electrochemical characterization to investigate the HF reduction process, X-ray photoelectron spectroscopy to characterize SEI chemistry, wide angle X-ray scattering to probe the nanostructure of the initial SEI and crystallographic texture of electrodeposited lithium metal, scanning electron microscopy to observe the resulting lithium metal morphology, and operando small angle X-ray scattering to understand cyclability of columnar lithium. Our systematic experimental approach enables insights to be drawn concerning the underlying mechanisms of columnar lithium formation. This morphology arises from an SEI layer comprising crystalline LiF deposits, formed through selective reduction of HF, embedded in an amorphous matrix of solvent reduction products. This interphase structure contains fast lithium ion diffusion pathways which lead to a high nucleation density and uniform growth of lithium metal deposits. The mechanism proposed herein will help to inform future electrolyte additive design and rational cycling protocols for lithium metal batteries. Figure 1

Early age properties of alkali-activated cement and class G cement under different saturation conditions in oil well applications

This experimental study evaluates the early-age properties of one-part alkali-activated cement (AAC) and class G cement (GC) under three subsurface curing conditions of water, brine, and carbon dioxide (CO2)-saturated water. The novel one-part AAC used in this study consist of fly ash and slag as the mineral precursors activated by a waste glass/sodium hydroxide-based solid alkali activator. The fresh and hardened properties of AAC and GC were characterised using rheology, strength, and microstructural tests. AAC showed relatively lower flow and setting time than GC under ambient conditions. Both the yield stress and plastic viscosity of AAC were reduced at elevated temperatures. AAC showed comparable strengths under water, higher strengths under brine, and lower strengths under CO2 saturation conditions compared to GC. Microstructural tests of GC evidenced the precipitation of chloride salt and leaching of Portlandite under brine conditions. A higher total porosity of AAC was reported with poorly crystalline calcium carbonate deposits under CO2 saturation. The early strength of one-part AAC should be improved by using suitable additives before their use for oil well-cementing, especially in CO2-rich conditions.

Development of a water-based acrylic paint with resistance to efflorescence and test method to determine the appearance of stains

Efflorescence are crystalline deposits of salts that appear on the surface of paints used to cover building walls. This pathology is not related to the quality of the paint, but to the quality of the construction buildings materials when moisture leaches the salts inside them. In this way, the aim of this work was to develop a water-based acrylic paint with higher resistance to efflorescence stains. Initially, it was necessary to develop a method to detect the formation of efflorescence in a short period of time. The method with the best results was to submit the ceramic specimen in aqueous solution of NaCl (5%). As the reference paint showed efflorescence stains, test paints were developed using two surfactants (polyether dimethylpolysiloxane and hydroxy thioether) at 0.1 and 0.6 mass % concentrations. Also, elastomeric, and acrylic styrene resins were added to the reference paint. The rationale for the use of surfactants was to reduce the surface tension of the paint on the surface of the masonry, making the paint flow better into the pores and, consequently, blocking the migration of salts to the surface. However, the contact angles of the developed paints on the masonry surface were greater than the reference paint, that was waterproof. If the solid surface were porous, perhaps the results would be different. Finally, it was possible to develop a paint resistant to stains caused by efflorescence, using elastomeric resin.