Salt Solution Research Articles

Systematic long-term investigation on Cu2ZnCdS4 wide band gap semiconducting materials for optics and luminescence applications

Copper Zinc Cadmium Sulfide (Cu2ZnCdS4) semiconducting material compound synthesized using a new economic beneficial route. Copper sulfate, zinc sulfate, cadmium sulfate and thiourea salt solutions were utilized for Cu2ZnCdS4 compound formation. Basic characteristics like pH value, electrical conductivity, concentration measurements were investigated for several hundred samples. Optics transmittance was investigated by UV – Vis spectrophotometer within the 350 to 950 nm range. Photo luminescence measurement was examined by using photo–fluorometer. Optic properties of Cu2ZnCdS4 compound were investigated through photo-calorimeter measurements including mixed wavelength bands. The real time investigated noteworthy results from several hundred samples are presented and discussed.

Correlation between subretinal tissue plasminogen activator and air injection rates with pressure in a retina mimicking model

By investigating the correlation between the injection rate and pressure of subretinal tissue plasminogen activator (tPA) and air using a standard Viscous Fluid Control (VFC) system with a 38-gauge cannula, we aimed to establish guidelines for stable injections. We fabricated a retina mimicking model (RMM) with 0.25% agarose solution and an aluminum plate, and substituted submacular hemorrhage (SMH) and tPA with blood-mimicking fluid (BMF) and balanced salt solution (BSS), respectively. The diameter of the pre-bleb mimicking SMH in RMM was 1.30 ± 0.16 cm, increasing to 1.98 ± 0.24 cm and 1.83 ± 0.22 cm after bleb propagation with BSS and air, respectively. BSS injection rates were 2.86 ± 0.04 µl/sec, 6.74 ± 0.48 µl/sec and 8.55 ± 0.16 µl/sec at 8, 12, and 16 psi, respectively. Air injection rates were 37.98 ± 3.11 µl/sec, 79.01 ± 5.13 µl/sec and 156.06 ± 13.72 µl/sec at 2, 3 and 4 psi, respectively. By experimenting with different pressures in the RMM, we found 12 psi to be the minimum for proper BSS injection and 2 psi for air. These findings provide crucial parameters for safer surgery to prevent irreversible damage.

On the Model of Transport of Salt Solution in a Xylem

We consider a model for vertical lifting of an aqueous solution of salts in a xylem. We analyzed changes of movement of the considered solution depending on various parameters. We consider an analytical approach for analysis of the considered model. The approach gives a possibility to take into account changes of parameters in space and time, as well as the nonlinearity of the considered processes.

Combined Surgical Approach for Repair of Refractory Macular Hole in Myopic Traction Maculopathy

Purpose: To present a combined surgical approach for repair of a persistent full-thickness macular hole (MH) in patients with myopic traction maculopathy. Methods: Two cases were evaluated. Results: Combining a macular buckle and pars plana vitrectomy with a controlled subretinal injection of a balanced salt solution resulted in MH closure and vision improvement in both cases. Case 1 also had significant recovery of macular sensitivity on microperimetry evaluation. Conclusions: Retinal redetachment was avoided by using the buckle indentation to provide external support of the posterior pole, resulting in successful closure of the MH and improvement in functional outcomes.

Vitreous Hydro-dissection with a Flute Needle for Inducing Posterior Vitreous Detachment in Pediatric Retinopathies

Purpose: To present a novel intraoperative technique using a flute needle to induce posterior vitreous detachment (PVD) in pediatric retinal cases. Methods: Following 23-gauge pars plana vitrectomy in pediatric eyes with complex vitreoretinal disease, triamcinolone is applied for staining, and vitreous hydro-dissection is performed. A flute needle containing basic salt solution (BSS) is introduced to separate the thin residual posterior vitreous cortex from the retina near the vascular arcades. Gentle taps allow balanced salt solution (BSS) to enter the vitreous crevice, with controlled oscillation facilitating separation. PVD is then induced, and the vitrector is used to lift and complete the detachment. Results: Vitreous hydro-dissection with a flute needle was effective in inducing PVD in pediatric eyes with complex vitreoretinal disease. We report no intraoperative or postoperative complications. Conclusion: This adjuvant vitreous hydro-dissection technique facilitates PVD induction and may reduce the associated risk of iatrogenic retinal damage.

Gastrointestinal parasites in free grazing goats from Ayacucho, Peru: prevalence and risk factors associated with infection in herds

This study assessed the prevalence and risk factors associated with gastrointestinal parasite infection in goats in Ayacucho, Peru. Fecal samples were collected from a total of 254 goats from four districts of Ayacucho: Ocaña (89), Colca (76), Pacaicasa (64), and Luricocha (25) during the dry season; recording the location, sex, and age of the animals. The fecal samples were analyzed using the flotation technique in salt and sugar solution, and modified McMaster egg counting techniques for eggs/oocysts (epg/opg) of gastrointestinal parasites. The associations between location, sex, and age with the prevalence of gastrointestinal parasites were analyzed using the chi-square test. Fecal samples showed an overall parasite prevalence of 87.80%. The identified parasites were Eimeria spp. (86.22%), Strongyle type eggs (STE) (65.75%), Skrjabinema spp. (7.87%), Trichuris spp. (3.15%) and Moniezia spp. (3.15%). There was a significant association between the location and the presence of parasites (p < 0.05); where STE was more prevalent in the district of Colca (98.68%); Trichuris spp. in Pacaycasa (9.38%); Skrjabinema spp. (48.00%), Moniezia spp. (12.00%) and Eimeria spp. (100%) were more prevalent in Luricocha. Sex had a significant association with the prevalence of Eimeria spp., Skrjabinema spp. and Moniezia spp. (p < 0.05); while age had a significant association with parasitosis only for Trichuris spp. and Moniezia spp. (p < 0.05). The epg/opg values revealed a higher parasite burden in goats from Colca compared to the other locations (p < 0.05). There was also no statistical relationship between fecal egg/oocyst counts and sex or age, nevertheless, there were moderate and high parasitic burdens. The high prevalence of parasites such as nematodes, cestodes, and coccidia suggests the need to implement strategic control and prevention programs in free-grazing goats. Location and sex were the most relevant risk factors for parasitosis in Ayacucho, Peru.

High-yield atmospheric water capture via bioinspired material segregation.

Transforming atmospheric water vapor into liquid form can be a way to supply water to arid regions for uses such as drinking water, thermal management, and hydrogen generation. Many current methods rely on solid sorbents that cycle between capture and release at slow rates. We envision a radically different approach where water is transformed and directly captured into a liquid salt solution that is suitable for subsequent distillation or other processing using existing methods. In contrast to other methods utilizing hydrogels as sorbents, we do not store water within hydrogels-we use them as a transport medium. Inspired by nature, we capture atmospheric water through a hydrogel membrane "skin" at an extraordinarily high rate of 5.50 kgm[Formula: see text]d[Formula: see text] at a low humidity of 35%. and up to 16.9 kgm[Formula: see text]d[Formula: see text] at higher humidities. For a drinking-water application, calculated performance of a hypothetical one-square-meter device shows that water could be supplied to two to three people in arid environments. This work is a significant step toward providing new resources and possibilities to water-scarce regions.

Molecular dynamics insights into the dynamical behavior of structurally modified water in aqueous deep eutectic solvents (ADES).

Recent studies have demonstrated that the presence of water in deep eutectic solvents (DESs) significantly affects their dynamics, structure, and physical properties. Although the structural changes due to the addition of water are well understood, the microscopic dynamics of these changes have been rarely studied. Here, we performed molecular dynamics simulation of 30% (v/v) (∼0.57 molar fraction) water mixture of DES containing CH3CONH2 and NaSCN/KSCN at various salt fractions to understand the microscopic structure and dynamics of water. The simulated results reveal a heterogeneous environment for water molecules in aqueous DES (ADES), which is influenced by the nature of the cation. The diffusion coefficients of water in ADESs are significantly lower than that in neat water and concentrated aqueous NaSCN/KSCN solution. When Na+ ions are replaced by K+ ions in the ADES system, the diffusion coefficient increases, which is consistent with the measured nuclear magnetic resonance data. Self-dynamic structure factor for water and other simulated dynamic quantities, such as reorientation, hydrogen-bond, and residence time correlation functions, show markedly slower dynamics inside ADES than in the neat water and aqueous salt solution. Moreover, these dynamics become faster when Na+ ions in ADES are replaced by K+ ions. The results suggest that the structural environment of water in Na+-rich ADES is rigid due to the presence of cation-bound water and geometrically constrained water. The medium becomes less rigid as the KSCN fraction increases due to the relatively weaker interaction of K+ ions with water than Na+ ions, which accelerates the dynamical processes.

Solid–Liquid Phase Equilibria of the Aqueous Quaternary System Rb+, Cs+, Mg2+//SO42− - H2O at T = 323.2 K

Sulfate-type salt lakes constitute over half of the total salt lakes in China and are rich in rare elements, such as rubidium and cesium. However, the complex interactions between ions make the separation and extraction process quite challenging. To address this, phase equilibrium studies were conducted on the sulfate system containing rubidium, cesium, and magnesium. Specifically, the phase equilibria of the aqueous quaternary system Rb+, Cs+, Mg2+//SO42− - H2O at 323.2 K were investigated using the isothermal dissolution method. The solubility, density, and refractive index of the system were experimentally measured. The results indicate that the system at 323.2 K belongs to a complex type with the formation of one solid solution (Rb, Cs)2SO4 and two double salts (Rb2SO4·MgSO4·6H2O, Cs2SO4·MgSO4·6H2O). The corresponding phase diagram consists of four quaternary invariant points, nine univariate curves, and six crystallization regions. Among these, the crystalline region for Cs2SO4·MgSO4·6H2O is the largest, while that for the single salt Cs2SO4 is the smallest. Moreover, the crystalline regions for the double salt and solid solutions are significantly larger than those for the single salt, highlighting the difficulty in separation of valuable single salts. A comparison of multi-temperature phase diagrams from 298.2 K to 323.2 K reveals that the crystalline form of MgSO4 changes from MgSO4·7H2O (298.2 K) to MgSO4·6H2O (323.2 K). As the temperature increases, the phase regions for Rb2SO4, Cs2SO4, (Rb, Cs)2SO4, and Cs2SO4·MgSO4·6H2O expand, while the phase region of Rb2SO4·MgSO4·6H2O contracts, indicating that the single salts (Rb2SO4, Cs2SO4) are more readily precipitated at higher temperature, which provides theoretical guidance for the future production and separation of Rb, Cs, and Mg from sulfate-type salt lakes.

Is Native Mass Spectrometry in Ammonium Acetate Really Native? Protein Stability Differences in Biochemically Relevant Salt Solutions.

Ammonium acetate is widely used in native mass spectrometry to provide adequate ionic strength without adducting to protein ions, but different ions can preferentially stabilize or destabilize the native form of proteins in solution. The stability of bovine serum albumin (BSA) was investigated in 50 mM solutions of a variety of salts using electrospray emitters with submicron tips to desalt protein ions. The charge-state distribution of BSA is narrow (+14 to +18) in ammonium acetate (AmmAc), whereas it is much broader (+13 to +42) in solutions containing sodium acetate (NaAc), ammonium chloride (AmmCl), potassium chloride (KCl), and sodium chloride (NaCl). The average charge state and percent of unfolded protein increase in these respective solutions, indicating greater extents of protein destabilization and conformational changes. In contrast, no high charge states of either bovine carbonic anhydrase II or IgG1 were formed in AmmAc or NaCl despite their similar melting temperatures to BSA, indicating that the presence of unfolded BSA in some of these solutions is not an artifact of the electrospray ionization process. The charge states formed from the nonvolatile salt solutions do not change significantly for up to 7 min of electrospray, but higher charging occurs after 10 min, consistent with solution acidification. Formation of unfolded BSA in NaAc but not in AmmAc indicates that the cation identity, not acidification, is responsible for structural differences in these two solutions. Temperature-dependent measurements show both increased charging and aggregation at lower temperatures in NaCl:Tris than in AmmAc, consistent with lower protein stability in the former solution. These results are consistent with the order of these ions in the Hofmeister series and indicate that data on protein stability in AmmAc may not be representative of solutions containing nonvolatile salts that are directly relevant to biology.

Methodological approaches to the comparative assessment of cellular reactions of innate immunity in mollusk &lt;I&gt;Pomacea&lt;/I&gt; sp. (&lt;I&gt;Caenogastropoda, Ampullariidae&lt;/I&gt;) in experimental aseptic inflammation

One of the significant methodological problems that arise in the study of cells of the innate immunity of invertebrates is the unsuitability of culture media and even salt solutions intended for mammals and humans. Another important methodological point is the significantly pronounced reactions of coagulation, which play an important protective role in all invertebrates, but manifest themselves in vitro in cellular suspensions prepared even with optimal saline solutions for this animal. To solve this problem, researchers widely use an anticoagulation buffer with ethylenediaminetetraacetic acid (EDTA) even in functional tests. From the standpoint of traditional approaches of mammalian immunology, the use of EDTA is possible only for the study of cell morphology, but not their functions. The aim of the work is to adapt methodological approaches to the comparative assessment of cellular reactions of innate immunity in Pomacea sp mollusks in experimental aseptic inflammation. To evaluate the functions of phagocytic cells in mollusk Pomacea sp., we used a complete salt solution (CSS) with optimal concentrations of glucose, calcium ions, magnesium with addition to prevent coagulation, cellular aggregation and degranulation instead of EDTA sodium salt of heparin at a concentration of 100 IU/mL (CSS-hep). As a result of a specially conducted experiment, it was shown that during incubation of hemolymph cells in this solution, their viability is preserved, evaluated by flow laser cytometry during incubation with annexin V-PE (PE Annexin V) and 7-aminoactinomycin D (7- AAD), as well as in a test with trypan blue. The possibility of studying the phagocytic activity and a phagosome acidification of leukocytes from hemolymph, hematopoiesis organ (kidney) and the focus of inflammation induced by intramuscular injection of sterile suspension of zymosan using CSS-hep is shown. Unlike the Limnaea stagnalis and Biomphalaria glabrata mollusks, in which the production of reactive oxygen species by phagocytes in the luminol-dependent chemiluminescence reaction is well documented, we were unable to induce this reaction in Pomacea sp. mollusks. In a specially conducted experiment, we did not reveal the effect of the sodium salt of heparin at a concentration of 100 IU/mL on the production of reactive oxygen species by rat phagocytes.

Effects of salt stress on the fruit and yield quality of some selected tomato (&lt;i&gt;Lycopersicum esculentum&lt;/i&gt; L.) varieties.

The growth, production, and nutritional characteristics of crops are impacted by abiotic factors such as salinity stress. The study aimed to assess the impact of salt stress on the fruit and yield characteristics of three distinct tomato cultivars, namely Rio, Dan syria, and UTC. Salt solutions with varying concentrations of NaCl were created by dissolving NaCl in deionized water. Four treatments were established, consisting of solutions with salt concentrations of 0g/L (control, without salt), 0.5g/L, 1.0g/L, and 1.5g/L. Each treatment was reproduced three times. The NaCl solutions were administered with a frequency of 7 days. The data in the study underwent Analysis of Variance (ANOVA). Rio outperformed the other varieties in terms of fruit quantity, fresh fruit weight, and fruit pericarp thickness under high salt stress, closely followed by UTC variety. The study also found that Dan syria performed better than the other varieties in terms of fresh and dry weight of shoot, as well as fresh weight of root, under mild and extreme salinity stress. However, Rio performed better than the other varieties in terms of dry weight of root under both mild and extreme salinity stress. The salt tolerance index of the Rio, UTC, and Dan Syria varieties under extreme salinity stress are 46.79%, 20.64%, and 34.70% respectively. This indicated that the Rio variety is the most salt-tolerant of the three types, with Dan Syria variety coming close.

Effect of Chloride Solution on Liquid Limit, and Plasticity Index of Soil in Selected Sites in Erbil /North Iraq

This study is an attempt to investigate the effect of NaCl, CaCl2, KCl, and NH4Cl solutions with different concentrations (2.5%, 5%, 7.5%) on the liquid limit, plastic limit, and plasticity index of Sarbasty and Mamwastayan soil samples /Erbil Governorate. The soil samples' liquid and plastic limits were found by using the cone penetrometer method. The Results showed that the soil's liquid, plastic limits, and Plasticity index decreased with increasing salt solution concentration. Maximum reduction of liquid limit and plastic limit in Sarbasty was from 53.6 to 34.3 and in Mamwastayan from 35.9 to 27.2, both accomplished by adding a concentration of 7.5% of KCl and CaCl2 respectively. According to the Unified Soil Classification System, the Sarbasty soils were classified as high plasticity clay (CH), and Mamwastayan low plasticity clay (CL). After adding different concentrations of salt solution to the soil, the Sarbasty soil classification changed from CH to CL. Mineralogically these soils are composed of non-clay minerals of calcite and quartz and clay minerals consisting of Montmorillonite, Chlorite, swelling Chlorite, Kaolinite, Illite, Palygorskite, and Illite- Chlorite. Sarbasty soil was the most effective salt chloride solution than the Mamwastayan soil sample swelling.

Establishing fire protection patterns in wood using impregnation compositions from inorganic salts

An issue related to using inorganic salts for fire protection of wood is to ensure their flame-inhibiting ability and compatibility with wood and application technology. That is why the object of research was to establish the effectiveness of inhibitory properties of mixtures of inorganic salts during interaction with the flame and enabling interplay with wood. A synergistic increase in the inhibitory capacity of mixtures of aqueous solutions of salts of diammonium phosphate and ammonium sulfate at a ratio of 2:1, and for a mixture based on orthophosphoric acid, urea, and oxyethylidenediphosphonic acid in the concentration range of 20–25 % by mass, has been proven. During the interaction of the specified mixtures with the wood surface, it was found that after application to the wood surface, the dispersed component of the free energy of the wood surface decreased to zero; instead, the polar component increased 13 times, which indicates a change in the wood surface. During the tests of wood samples on the effect of the burner flame, it was found that the untreated sample ignited on second 53, and the flame spread throughout the sample for 102 s. On the other hand, the samples treated with a mixture of an aqueous solution of phosphate and ammonium sulfate, as well as a mixture of aqueous solutions based on orthophosphoric acid and urea and oxyethylidenediphosphonic acid, did not catch fire, the flame did not spread over the surface, and the flammability index was 0. The practical significance is that the results were taken into account when designing flame retardant compositions for wood. Thus, there are reasons to assert the possibility of targeted regulation of wood protection processes through the use of mixtures of inorganic salts capable of forming a protective layer on the surface of the material that inhibits the burning of wood

A Systematic Review of Renal Perfusion in Complex Abdominal Aortic Aneurysm Open Repair

Introduction: This systematic review aims to analyze the current literature regarding 30-day mortality and postoperative acute kidney disease (AKI) in complex abdominal aortic aneurysms (cAAAs), which included juxtarenal aortic aneurysm (JAA), suprarenal aortic aneurysm (SRAA), and type IV thoracoabdominal aortic aneurysm (TAAA) open surgery (OS), to evaluate the impact of renal perfusion on AKI and to try to define which is the best way to perform it. Methods: A literature search in PubMed and Cochrane Library was performed, and articles published from January 1986 to January 2024 reporting on JAA, SRAA, and TAAA type IV open surgery management were identified. Multicenter studies, single-center series, and case series with ≥10 patients were considered eligible. Comparisons of outcomes of patients who underwent OS for complex abdominal aortic aneurysms (cAAAs) with or without perfusion of the renal arteries were analyzed when available. The titles, abstracts, and full texts were evaluated by two authors independently. The primary outcomes included AKI and 30-day mortality rates. The new-onset dialysis rate was considered a secondary outcome. Results: A total of 295 articles were evaluated, and 21 were included, totaling 5708 patients treated for cAAAs with OS. The male patients totaled 4094 (71.7%), with a mean age of 70.35 ± 8.01 and a mean renal ischemia time of 32.14 ± 12.89 min. Data were collected and analyzed, at first in the entire cohort and then divided into two groups (no perfusion of the renal arteries—group A vs. selective perfusion—group B), with 2516 patients (44.08%) who underwent cAAAs OS without perfusion of the renal arteries and 3192 patients (55.92%) with perfusion. In group B, four types of renal perfusion were reported. Among the 21 studies included, 10 reported on selective renal perfusion in cAAA OS, with several types of fluids described: (1) “enriched” Ringer’s solution, (2) “Custodiol” (Istidine-tryptophan-ketoglutarate or Custodiol HTKsolution), (3) other cold (4 °C) solutions (i.e., several combinations of 4 °C isotonic heparinized balanced salt solution containing mannitol, sodium bicarbonate, and methylprednisolone), and (4) warm blood. Thirty-day mortality for patients in group A was 4.25% (107/2516) vs. 4.29% (137/3192) in group B. The reported incidence of AKI and new onset of dialysis was, respectively, 22.14% (557/2516) and 5.45% (137/2516) for group A and 22.49% (718/3192) and 4.32% (138/3192) for group B. A total of 579 patients presented with chronic kidney disease (CKD) at admission across all studies, which included 350 (13.91%) in group A vs. 229 (7.17%) in group B. Acute kidney injury, 30-day mortality, and new-onset dialysis rate were reported in four subgroups: (1) In the “Ringer” group, 30-day mortality was 2.52% (3/113), AKI affected 27.73% (33/119) of patients, and the new-onset dialysis rate was 2.52% (3/113). (2) In the “Custodiol” group, 30-day mortality was 3.70% (3/81), AKI affected 20.17% (24/81) of patients, and the new-onset dialysis rate was 2.46% (2/81). (3) In the “cold solutions” group (i.e., NaCl and mannitol), 30-day mortality was 4.38% (130/2966), AKI affected 21.81% (647/2966) of patients, and the new-onset dialysis rate was 4.48% (133/2966). (4) In the “Warm blood” group, 30-day mortality was 3.85% (1/26), AKI affected 53.84% (14/26) of patients, and the new-onset dialysis rate was 0% (0/26). Conclusions: This systematic review highlights the lack of standard definitions for AKI, CKD, and the type of renal perfusion. Despite similar results in terms of AKI and 30-day mortality, renal perfusion seems to be protective of the new-onset hemodialysis rate. Moreover, Custodiol appears to have lower rates of AKI and hemodialysis than the other perfusion types. A prospective randomized controlled trial to perform further subgroup analysis and research the various types of renal perfusion may be necessary to identify possible benefits.

Facile and Environmentally Friendly Synthesis of Ga2O3/MFI Catalysts for Propane Dehydrogenation.

A GaOx-based catalyst is recognized as a promising catalyst for dehydrogenation of light alkanes. Conventionally, impregnation and calcination are necessary processes for the loading of GaOx. However, the incomplete impregnation of gallium salt solution would generate wastewater, and the calcination for the dissociation of gallium salt would release harmful gases, such as SOx, NOx, and HCl. Meanwhile, the high temperature results in an excessive energy cost and undesired GaOx particle aggregation. Here, we report a facile and environmentally friendly method for the synthesis of GaOx-based catalysts. The gallium salt solution was replaced directly with liquid gallium (LG). Through a simple physical mixing method at room temperature, uniform GaOx nanoparticles with diameters of around 3.5 nm were loaded onto the surface of silicalite-1 (S-1). With the optimal GaOx/MFI catalyst, the propane conversion and propylene selectivity reached 22.9 and 90.1%, respectively, in the propane dehydrogenation reaction. The work offers a clean and economical strategy utilizing liquid metal (LM) as an impregnation solution for the preparation of GaOx-based catalysts.

Citrus bliss: potassium, sodium, and calcium silicates secrets for post-harvest diseases of fruit defense

Biotic stress significantly challenges the global citrus industry. Major post-harvest issues include diseases caused by Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii, Alternaria alternata, and Phytophthora citrophthora. The negative impact of chemical fungicides on the environment and health necessitates eco-friendly alternatives. This study examines the effectiveness of sodium, potassium, and calcium silicates against common citrus diseases. In vitro tests evaluated mycelial growth inhibition using silicate concentrations from 0 to 10,000 ppm after 7 days at 25°C. Sodium silicate showed the highest efficacy, completely inhibiting P. digitatum and P. italicum at 2000 ppm. Potassium and calcium silicates achieved 100% inhibition against Penicillium spp. at a concentration of 1%. In vivo tests on Sidi Aissa clementines assessed the preventive and curative effects of 1, 2, and 6% silicate salt solutions. Sodium silicate prevented 41% of brown rot, 72% of sour rot, and 100% of green mold at 6%. Calcium silicate at 6% significantly reduced blue mold and black rot by 32% and 74%, respectively. Sodium silicate was most effective in curative treatments, suggesting its potential as a pre- or post-harvest spray to control P. digitatum, P. italicum, and G. citri-aurantii.

Influence of Oligomeric Lactic Acid and Structural Design on Biodegradation and Absorption of PLA-PHB Blends for Tissue Engineering

The advancing development in biomaterials and biology has enabled the extension of 3D printing technology to the bioadditive manufacturing of degradable hard tissue substitutes. One of the key advantages of bioadditive manufacturing is that it has much smaller design limitations than conventional manufacturing and is therefore capable of producing implants with complex geometries. In this study, three distinct blends of polylactic acid (PLA) and polyhydroxybutyrate (PHB) were produced using Fused Deposition Modeling (FDM) technology. Two of these blends were plasticized with oligomeric lactic acid (OLA) at concentrations of 5 wt% and 10 wt%, while the third blend remained unplasticized. Each blend was fabricated in two structural modifications: solid and porous. The biodegradation behavior of the produced specimens was examined through an in vitro experiment using three different immersion solutions: saline solution, Hank’s balanced salt solution (HBSS), and phosphate-buffered saline (PBS). All examined samples were also subjected to chemical analysis: atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS). The results of the degradation experiments indicated a predominantly better absorption capacity of the samples with a porous structure compared to the full structure. At the same time, the blend containing a higher concentration of OLA exhibited enhanced pH stability over the evaluation period, maintaining relatively constant pH values before experiencing a minor decline at the end of the study. This observation indicates that the increased presence of the plasticizer may provide a buffering effect, effectively mitigating the acidification associated with material degradation.

Isothermal compressibility and water self-diffusion coefficient in supercooled salt aqueous solutions using the Madrid-2019 model

The isothermal compressibility and self-diffusion coefficient of water in Li + , Na + , K + , Mg 2 + and Ca 2 + chloride and sulfate salts aqueous solutions is calculated by means of molecular simulations using the Madrid-2019 force-field, that uses TIP4P/2005 model for water and assigns scaled charges for ions. Our simulations predict that the isothermal compressibilities of these salts retain the anomalous behaviour of water, i.e. compressibility increases as temperature decreases, contrary to the behaviour of normal liquids. A maximum in the isothermal compressibility, analogous to that of pure water, is observed for some of the salt solutions. For the 1 m NaCl solution, simulations are performed at several pressures up to 1000 bar to estimate the location of the second critical point. We estimate that the liquid-liquid critical point is located at 190 K and 1000 bar, i.e. it is shifted to slightly higher temperatures and lower pressures with respect to the most accurate estimation of its location in pure TIP4P/2005 water (172 K and 1861 bar). Regarding the self-diffusion of water, all salts increase water mobility in the very supercooled regime (at temperatures within 200–230 K), with K 2 SO 4 producing the largest increase in water mobility, while MgCl 2 and MgSO 4 are the least effective in enhancing the self-diffusion coefficient of water.

Use of Cohesive Viscoelastic Agents to Facilitate Safe Removal of Posterior Segment Intraocular Foreign Bodies

Purpose: To assess the ability of viscoelastic agents and perfluoro-N-octane (PFO) to safely remove an intraocular foreign body (IOFB). Methods: A 23-gauge pars plana vitrectomy and lensectomy were performed in a porcine eye. A 5.0 mm metallic IOFB was inserted through a corneal paracentesis and dropped into the vitreous cavity. The posterior segment was filled completely with a balanced salt solution, cohesive viscoelastic, or dispersive viscoelastic or partially filled with PFO under a balanced salt solution. The IOFB was then brought anteriorly and released. Each test was repeated multiple times and videorecorded. Results: The IOFB fell with high velocity through the balanced salt solution–filled vitreous cavity. When the eye was filled with either of the 2 viscoelastic agents, the IOFB did not move or moved posteriorly extremely slowly. A vitreous cavity filled partially with PFO led to deflection of the object’s path, with the peripheral retina being struck, or the IOFB dropping straight down and striking the macula. PFO and the cohesive viscoelastic were easily removed from the eye with the vitrectomy instrument. The dispersive viscoelastic could not be completely removed and repeatedly clogged the vitreous cutter. Conclusions: Filling the posterior segment with a cohesive viscoelastic agent may significantly increase the safety and ease of IOFB removal.