Fluid pH Research Articles

RS-AAT with distributed permeable pipes and alkaline water: Enhancing concrete durability through chloride reduction, pH optimization, and pore structure improvement

Reverse-seepage and Saturation based Active Anti-corrosion Technology (RS-AAT) is a novel and environmentally-friendly approach that enhances the ability of unsaturated concrete in marine alternating wet-dry areas to resist chloride ion intrusion. Comprehending its influence on ions transport and the pore structure within the concrete is vital for assessing the rationality of the technique and further predicting its service life. In this study, cross-section specimens of cast in situ concrete piles with RS-AAT were exposed to a chloride wet-dry cycling environment for 150 days. Spatiotemporal variation patterns of chloride ion content, pore fluid pH, and pore structure in the concrete cover were investigated by free chloride titration, pH determination, and mercury intrusion porosimetry (MIP). The findings indicate that RS-AAT can effectively inhibit chloride ion intrusion into the protective layer of concrete. Moreover, implementing alkaline water in RS-AAT elevates the pore fluid pH and improves the compactness of the pore structure, especially diminishing the harmful pore ratio. Besides, increasing the number of distributed permeable pipes reinforces these effects and reduces the technology's dependence on water pressure. This insight demonstrates the viability of using alkaline water and distributed permeable pipes in RS-AAT to bolster the resistance of concrete structures to chloride ion erosion in an environmentally sustainable manner.

The geochemical evolution of basalt Enhanced Rock Weathering systems quantified from a natural analogue

Substantial quantities of fine-grained basaltic dust have fallen on South Iceland soils over at least the past 3300 years, making this region an ideal natural analogue to define the long-term consequences of current Enhanced Rock Weathering efforts. A relatively pristine South Iceland Gleyic/Histic Andosol, 3 m in height, receiving approximately 1250 mm of rainfall annually was selected for this study. This soil receives an estimated 500–800 g m−2y−1 of basaltic dust. The soil waters in this system were regularly sampled as a function of depth from May to November 2018. The fluid pH, alkalinity and the concentrations of most major elements increased with depth as the fluids became more reduced. In contrast, whereas numerous toxic trace metals are initially released to the fluid by the dissolution of the basalt near the surface they are scavenged at depth likely due to their uptake by secondary minerals. Equilibrium reaction path modelling suggests that 1) the added airborne basaltic dust dissolves throughout the soil column and 2) in total 0.26 cm3 of basalt dust dissolves per kg water in this soil–water system. Mass balance calculations indicate that the annual mass of basalt dissolved is less than 60 % of that added to the system, such that the mass of basaltic material in the soil column likely increases continuously over time. Basalt dissolution is maintained throughout the soil by the precipitation of Al-Si-minerals such as allophane, and organic anion ligands released from organic decay. These processes limit aqueous Al3+ activity and keep the soil waters undersaturated with respect to primary basaltic minerals and glass. The soil water pH is ∼6 and has a higher alkalinity than that of both Icelandic surface waters and the ocean. In contrast, if no basalt was present, the pH of the soil solutions would be 4.4, with zero alkalinity, illustrating the role of added basalt in drawing CO2 out of the atmosphere.

Factors affecting the rumen fluid foaming performance in goat fed high concentrate diet.

Feeding high concentrate diets is highly prone to rumen bloat in ruminants, which is very common in production. This study explored the factors responsible for the occurrence of foamy rumen bloat. The experiment was conducted using goats as test animals, fed high concentrate diets and scored for rumen distension into high, medium and low bloat score groups. Rumen fluid was collected from 6 goats in each group separately. The foaming production, foam persistence, pH value, viscosity and the content of protein, total saccharide and mineral elements in rumen original fluid (ROL) were measured, and the protein and total saccharide content in rumen foam liquid (RFL) and rumen residual liquid (RRL) were determined. The results showed that the protein content in rumen original fluid and rumen foam liquid was significantly higher than that in rumen residual liquid (p < 0.05), and the protein content in rumen foam liquid was 10.81% higher than that in rumen original fluid. The higher the rumen bloat score, the higher the foam production, foam persistence, viscosity, protein, Ni, Mg, Ca, and K concentrations of the rumen original fluid, and the lower the PH and Na concentrations of the rumen original fluid; correlation analysis showed that the viscosity of the rumen original fluid was significantly and positively correlated with the foam production and foam persistence (p < 0.05). Foaming production and foam persistence of rumen original fluid were significantly and positively correlated with the contents of protein, total saccharide, K, Ca, Mg and Ni (p < 0.05). and negatively correlated with the content of Na (p < 0.05); after controlling other components those were significantly related to the foaming performance of rumen original fluid only protein still was significantly positively correlated with the foam persistence of rumen original fluid (P<0.05). In summary, the contents of protein, total saccharide and mineral elements in the rumen fluid had a significant effect on the foaming performance of rumen in ruminants, with protein playing a decisive role and the other components playing a supporting role. Reducing the content of protein in the diet in production is beneficial to reduce the occurrence of rumen bloat in ruminants.

Bacterial Vaginosis (BV) and Vaginal Microbiome Disorders in Women Suffering from Polycystic Ovary Syndrome (PCOS).

Introduction: Polycystic ovary syndrome (PCOS) is a multifactorial, heterogeneous endocrine and metabolic disorder in women. Due to its association with the menstrual cycle and fertility disorders, the importance of this problem is emphasized especially in patients of reproductive age. Based on a number of analyses, the effect of PCOS on altering the diversity of the microbiome (e.g., intestinal or vaginal) is suggested. Vaginal dysbiosis can result in BV (bacterial vaginosis). The purpose of this study was to assess the prevalence of BV in patients with PCOS, as well as to determine the most reliable diagnostic factors. Material and Methods: Retrospective analysis of microbiological findings (2018-2022) of PCOS patients (n = 594) of reproductive age. The present analysis focused on the results of patients with PCOS (n = 380) and vaginal discharge with pH ≥ 4.4 and suspected BV. Biological material was a vaginal swab/vaginal secretion. The most commonly used routine methods for assessing BV were the Amsel analysis and the Nugent scoring system. Results: Patients with PCOS and vaginal fluid pH ≥ 4.4 and suspected BV (n = 380) accounted for 64% of all PCOS patients (n = 594). The relationship between pH and detection of "clue cells" showed significant dependency and increased with leukocytes. The pH measurement also showed dependency on high G. vaginalis counts. In addition, the elimination of lactic acid bacteria (LAB) in vaginal secretions was associated with an increase in the number of leukocytes with increasing pH values. A marked increase in G. vaginalis was found in more than half (56.8%) of PCOS women (n = 380) with suspected BV. No dependency was observed between the absence of LAB and the diagnosis of BV on a positive G. vaginalis culture. Of the n = 380 patients with PCOS, 191 (50%) had a Nugent score ≥ 7 positive for BV. No dependency was observed between the number of patients with Candida sp. in vaginal secretions and pH, BV (with clue cells), or elevated leukocyte levels. The LRM was adjusted and the statistical model represented by the following formula was obtained: log(p/(1 - p)) = -1.18 + 1.24 × Group4.6 + 1.08 × Group4.8 + 1.66 × Group5.4. Conclusions: Based on the present analysis, BV appears to be more common in patients with PCOS than in the non-PCOS population. Chronic inflammation in PCOS patients and abnormalities in the vaginal microbiome may predispose to the development of BV. In women with PCOS, BV may be one of the unrecognized causes of infertility or complications of pregnancy. Despite the potential link between PCOS and the development of BV, the extent to which this syndrome contributes to vaginal dysbiosis and reproductive complications requires further study.

Encapsulation of SE‐P47 phage specific to SalmonellaEnteritidis and evaluation of its stability

AbstractThis study was conducted to encapsulate the bacteriophage SE‐P47 target to Salmonella Enteritidis by extrusion method and to examine its stability. Screening and optimization of effective factors in the encapsulation process were performed using fractional factorial design and face‐centered central composite design, respectively. The optimum Na‐alginate concentration and the ratio of coating material to phage for the encapsulation of SE‐P47 phage were 1.5% (v/v) and 2:1, respectively. At the optimum encapsulation point, the highest encapsulation efficiency (98.52%), smallest capsule size (1.28 mm), and highest phage titer were achieved. When exposed to heat treatment at 80°C for 30 min, pH 2 and simulated gastric fluid (pH 2.0) for 120 min, the encapsulated phage maintained almost its stability, but the free (non‐encapsulated) phage almost lost its activity. Phage release from beads in simulated intestinal fluid reached 100% in 4 h. In addition, free and encapsulated phage completely maintained their activity for 12 months at 4 and 25°C. The Salmonella phage encapsulated in this study exhibits high stability in harsh conditions. Thus, this encapsulated phage has the potential to be used as a biocontrol agent or therapeutic purposes in the food chain.

Formulation of a probiotic product using Almond gum.

The application of probiotics in food has expanded significantly, yet its viability remains a challenge. In response to this issue, this study explores a unique approach. Almond gum, a natural extract from Prunus dulcis, is utilized as the primary carrier matrix for a novel probiotic product featuring Saccharomyces boulardii, a probiotic yeast. This study involves the entrapment of S. boulardii in almond gum through centrifugation (5 min at 1300 × g) and subsequent 24 h drying at 50 °C. Sensory evaluation and other investigations were conducted at different pH levels to assess viability and performance. Post-drying entrapment efficiency was 83.85%, underscoring the benefits of choosing almond gum as a carrier matrix. Promising results were observed from viability testing conducted in gastric juice (pH 1.2) and in simulated intestinal fluid (pH 6.8). Matrix stability was assessed by measuring cfu ml-1 following 7 days' storage at different temperatures, complemented by sensory analysis. Almond gum is a promising carrier matrix for probiotic products. Its high entrapment efficiency and its viability under challenging pH conditions demonstrate its efficacy. It is rich in carbohydrates and serves a dual purpose by acting as a prebiotic source, as confirmed through ultraviolet-visible (UV-visible) analysis. The study underscores the potential of this novel approach, providing insights into responses to viability challenges in probiotic food products. © 2024 Society of Chemical Industry.

Mucoadhesive Vaginal Tablets Containing Metronidazole: Screening of Optimal Natural Polymer in the Composition

(1) Background: The study aimed to compare the impact of various natural polymers–sodium alginate, acacia gum, carrageenan, guar gum, xanthan gum, and tragacanth on the formulation and the physical properties of mucoadhesive vaginal tablets containing metronidazole (167 mg/g). (2) Methods: The quality of the tablets prepared by direct compression was evaluated by pharmacopoeia tests (uniformity of mass, resistance to crushing, friability). Mucoadhesion of the tablets was characterized by swelling capacity and mucoadhesive strength, i.e., the force required to detach the tablet from the rabbit mucosa. In vitro drug release was performed by a modified dissolution method in paddle apparatus containing the simulated vaginal fluid (pH 4.5). Scanning electron microscopy observed morphological changes on the swollen tablets’ surface. (3) Results: Pharmacopoeia tests have shown that all prepared tablets met the requirements on quality. The highest mucoadhesive strength was noted in tablets containing guar and xanthan gum. The highest swelling capacity was possessed by tablets containing carrageenan. (4) Conclusions: Summarizing all tests’ results, sodium alginate can be considered the most suitable natural polymer in tablet formulation. The combination of polymers providing higher mucoadhesiveness and at the same time a prolonged release, e.g., xanthan or guar, together with sodium alginate, could also be of interest.

Acidity Is an Excellent Marker of Infection in Hip and Knee Arthroplasty

Background: The diagnosis of joint replacement infection is a difficult clinical challenge that often occurs when the implant cannot be salvaged. We hypothesize that the pH value of synovial fluid could be an important indicator of the inflammatory status of the joint. However, in the literature, there is a lack of data on the pH changes in hip and knee joint replacements and their relation to infection and implant failure. In this study, we aimed to measure the pH levels of synovial fluid in patients with hip and knee joint replacements. We also investigated the potential of pH measurement as a diagnostic tool for joint replacement infection. In this study, we recorded the pH values to be 7.55 and 7.46 in patients where Pseudomonas aeruginosa was identified as the cause of the prosthetic joint infection. We attribute this to the different environments created by this specific bacterium. In other cases where the pH was higher, chronic mitigated infections were diagnosed, caused by strains of Staphylococcus aureus, Streptococcus agalactiase, and coagulase negative staphylococcus. Materials and methods: In our cohort of 155 patients with implanted hip (THA; n = 85) or knee (TKA; n = 70) joint replacements, we conducted a prospective study with a pH measurement. Out of the whole cohort, 44 patients had confirmed joint replacement infection (28.4%) (44/155). In 111 patients, infection was ruled out (71.6%) (111/155). Joint replacement infection was classified according to the criteria of the Musculoskeletal Infection Society (MSIS) from 2018. Based on the measured values, we determined the cut-off level for the probability of ongoing inflammation. We also determined the sensitivity and specificity of the measurement. Results: The group of patients with infection (n = 44) had a significantly lower synovial fluid pH (pH = 6.98 ± 0.48) than the group of patients with no infection (n = 111, pH = 7.82 ± 0.29, p &lt; 0.001). The corresponding median pH values were 7.08 for the patients with infection and 7.83 for the patients with no infection. When we determined the cut-off level of pH 7.4, the sensitivity level of infected replacements was 88.6%, and the specificity level of the measurement was 95.5%. The predictive value of a positive test was 88.6%, and the predictive value of a negative test was 95.5%. Conclusions: Our results confirm that it is appropriate to include a pH measurement in the diagnostic spectrum of hip and knee replacements. This diagnostic approach has the potential to provide continuous in vivo feedback, facilitated by specialized biosensors. The advantage of this method is the future incorporation of a pH-detecting sensor into intelligent knee and hip replacements that will assess pH levels over time. By integrating these biosensors into intelligent implants, the early detection of joint replacement infections could be achieved, enhancing proactive intervention strategies.

Synergistic antibacterial effect of the pistachio green hull extract-loaded porphysome decorated with 4-nitroimidazole against bacteria

‘Active targeting’ refers to modifying a nanocarrier’s surface with targeting ligands. This study introduced an efficient approach for immobilizing imidazole-based drugs onto the metallated-porphyrin complex within the porphysome nanocarrier. To enhance cellular and bacterial uptake, a Ni-porphyrin with a fatty acid tail was synthesized and placed in the bilayer center of DPPC, facilitating receptor-mediated endocytosis. The Ni-porphyrin in the head group of the Ni-porphyrin-tail was placed superficially in the polar region of the membrane. Spherical unilamellar vesicle formation (DPPC: Ni-porphyrin-tail 4:1 mole ratio), as metallo-porphysome, was achieved through supramolecular self-assembly in an aqueous buffer. These vesicles exhibited a diameter of 279 ± 7 nm and a zeta potential of −15.3 ± 2.5 mV, showcasing their unique cytocompatibility. Nitroimidazole was decorated on the surface of metallo-porphysomes and pistachio green hull extract (PGHE) was loaded into the carrier for synergistic activity against (E. coli) and (S. aureus) bacteria strains. The physicochemical properties of Nitroimidazole-porphysome-PGHE, including size, zeta potential, morphology, loading efficiency, and release profile under various pH and temperature conditions in simulated gastrointestinal fluids were characterized. This combination therapy prevented bacterial cell attachment and biofilm formation in Caco-2 cells, as colon epithelial cells. The remarkable benefit of this system is that it does not affect cell viability even at 0.5 mg/ml. This study demonstrates the potential of a new co-delivery system using biocompatible metallo-porphysomes to decrease bacterial infections.

Manipulation of neonatal ruminal populations at birth results in sustained effects on microbial populations and measures of health and production in merino and suffolk lambs

The efficiency of the microbial-driven fermentation process in the rumen is closely related to the efficiency of the ruminant host. This experiment examined the effect of manipulating the neonatal microbiota on postnatal development, immune function and productivity (liveweight gain and wool growth parameters). The trial examined the differences between naturally inoculated lambs (maternal control, n = 21) and those given ruminal fluid, which had been collected from ruminally-cannulated ewes, fed either a roughage diet (roughage, n = 14), or a grain-based diet (high grain, n = 14). At lambing, newborn lambs were tagged and weighed. Inoculation lambs received 10 ml of rumen fluid per inoculation, daily, for a total of 7 inoculations. Live weight, body condition scores, wool growth (greasy and clean wool weights), wool length, mean fibre diameter, and differential blood cell counts, and IgG and IgA in both blood and saliva) were quantified from birth until week 18 (slaughter). Total feed intake was recorded from weaning. Ruminal fluid was collected by stomach tube from 12 lambs from each treatment group and their dams (n = 7–8 per treatment, with the lower number of ewes coming about through ewes that had twins) at time of weaning (week 10). The pH of the ruminal fluid, the density of ciliated protozoa in ruminal fluid, and the composition of the ruminal bacterial populations were analysed. At slaughter (week 18), ileal samples were taken from the same focal lambs as were used for microbial analysis. The artificial inoculations resulted in significant differences in ruminal bacterial genera to those of naturally inoculated lambs at time of weaning (some 3 months post-lambing). Significant differences were also apparent in ileal bacterial communities at slaughter, between lambs which had received the inoculum from roughage-fed ewes and naturally inoculated lambs. Both the efficiency (growth, condition, feed conversion efficiency, carcass weight) and indices of health (mortalities, red blood cell count, blood haemoglobin concentration, haematocrit, and eosinophil counts) of the inoculated animals, were affected negatively by the inoculations ( < 0.05). There was a significant interaction between inoculum source and breed in terms of effects on all parameters measured. The effects of the high grain inoculation were significantly affected by breed, with high grain merinos found to have reduced mean fibre diameter (P < 0.05) and increased wool growth relative to the maternal control (P = 0.035). This effect was not noted in the suffolks. In summary, we have demonstrated that long-term effects on ruminal and intestinal microbiota can be generated by intervention in the normal process of ruminal inoculation in neonatal lambs. Moreover, there appeared to be genetic differences in response to artificial inoculation. Whilst the effects of artificial inoculation in this trial were negative in terms of indices of health and production, further studies of maternal diet and its effects on the natural establishment of the neonatal microbiota are warranted given the persistence of the effects and the interaction with breed.

Hybrid Hydrogel-Magnet Actuated Capsule for Automatic Gut Microbiome Sampling.

Non-invasive, pill-sized capsules can provide intestinal fluid sampling to easily retrieve site-specific gut microbiome samples for studies in nutrition and chronic diseases. However, capsules with both automatic sampling and active locomotion are uncommon due to limited onboard space. This paper presents a novel hybrid hydrogel-magnet actuated capsule featuring: i) pH-responsive hydrogels that will automatically trigger fluid sampling at an environmental pH of 6 and ii) active locomotion by an external rotating magnetic field. Two capsule designs were fabricated (Design A: 31 μL sampling volume with dimensions 8 mm × 19 mm, Design B: 41 μL sampling volume with dimensions 8 mm × 21 mm). They were immersed in simulated gastric (pH = 1.2) and simulated intestinal fluid (pH = 6.8) to test for automatic intestinal fluid sampling. An external rotating magnetic field was applied to test for active locomotion. Finally, seal tests were performed to demonstrate sample contamination mitigation. Preliminary experiments showed that sampling occurred quickly and automatically in simulated intestinal fluid at 6-15 hours, active locomotion via rotation, rolling, and tumbling were possible at magnetic field magnitudes 10 mT, oil piston seals were better at mitigating sample contamination than water piston seals, and minimum o-ring seal pressures limits of 1.95 and 1.69 kPa for Design A and B respectively were sufficient against intra-abdominal pressures. This work presents the ability to impart capsule multi-functionality in a compact manner without onboard electronics or external triggering for sampling.

Cutting Fluid pH Value Maintenance in CNC Machine by Arduino Nano

Cutting fluid plays an important role in machining operations like milling, drilling, reaming, etc. In production industry such as automobile industries, aerospace industries, etc., soluble cutting fluids are mainly used for machining operations. The maximum service life of the cutting fluid is about 3 to 4 months in that industry, when they mixed with water, the cutting fluid will get dried out or converted into vapour due to heat generation and due to friction between the cutting tool and the components. The repeated use of cutting fluid for machining operations, the chemical and physical property of the cutting fluid will be changed. The proper mixing ratio of cutting fluid can be done with the help of Arduino nano device and valves, sensors. Automatic cutting fluid filling process can be done by proper Arduino coding. In the present study, the pH sensor is used to detect the pH level of cutting fluid and the Solenoid valves are electromagnetic valves, these valves are used to maintain the proper flow of cutting fluid and water mixture ratio, whenever the cutting fluid pH value differs from the fixed value, the pH sensor will indicate in Arduino nano. The mixing of cutting fluid and water is carried out by stirrer mechanism, which is attached at just above the cutting fluid tank. Control valve is used to control the flow of cutting fluid during the machining operation. The electric signal from touch sensor will stops automatically, when the cutting fluid in the tank reaches its maximum limit. In this paper, cutting fluid pH value is maintained automatically by Arduino nano device for CNC Machine in industries is discussed.

Induced Ruminal Lactic Acidosis in Sheep Treated with Various Remedial Agents in Libo Kemkem Districts, Northwest Ethiopia.

Grain overload is a ruminant metabolic disorder associated with overingestion or a sudden change to rapidly fermentable concentrate feeds. A randomized clinical trial was carried out in Libo Kemkem districts to investigate vital signs, ruminal fluid, and hematological changes in sheep related to grain overload and to assess the treatment efficacy of various remedial agents in Farta sheep breeds. All sheep were selected by using the simple random process, and categorized into four groups of eight animals groups I, II, and III in which each sheep was given 80 g of wheat flour per kg of body weight then baking soda, Magnalax, and digestive powder were treated successively, but group IV was the negative control group. The current clinical trial explained that all acidotic sheep had statistically significant (p < 0.0002) lower body temperature, rumen motility, protozoa activity, and ruminal fluid pH with 38.48 ± 0.20, 0.5 ± 0.89, 6 (75%), and 5.37 ± 0.34 mean value successively. Nevertheless, there were significant (p < 0.0059) increments in hematological variables including total red blood cell, total white blood cell, packed cell volume, and hemoglobin estimation with 14.05 ± 1.27, 12.71 ± 0.99, 40.78 ± 5.24, and 14.78 ± 1.83 mean value, respectively, before treatment in acidotic sheep. There were also vital sign increments including pulse rate, respiratory rate, skin turgor, and capillary refill time with 123.5 ± 27.1, 73.75 ± 12.71, 3 ± 1.78, and 3.37 ± 1.77 mean values, respectively, before medical treatment in acidotic sheep. Digestive powder was the first drug of choice, followed by Magnalax, and baking soda was ranked at the end based on clinical recovery. The treatment effectiveness illustrated that all treatments could cure the grain overload. Nevertheless, digestive powder is the drug of choice based on the clinical and systemic recovery of the sheep. In addition to this, sheep should be introduced gradually to concentrate rations over 2-3 weeks with a mixture of concentrate in the milled feed containing roughage.

Colorimetric microneedle sensor using deep learning algorithm for meat freshness monitoring

Currently, the developed testing methods determining meat freshness are time-consuming, inconvenient, or have high specialty requirements. Herein, we proposed a colorimetric microneedle sensor (CMS) using a deep learning algorithm for visualized meat freshness monitoring. The CMS was obtained by molding edible hydrogels containing pH-responsive anthocyanins, which change colors because of the structure change of anthocyanins in response to pH. When attached to meat, the CMS was capable of penetrating the meat and extracting tissue fluids by capillary action. With meat spoilage, the pH of the tissue fluid gradually rose, leading to a change in CMS from pink to purple and finally to dark blue. Thus, according to variations of CMS colors, in situ and visualized detection of meat freshness was achieved. Further, a deep learning algorithm was applied to integrate with CMS to form a smartphone application (App), allowing for more convenient and accurate freshness detection. Images of CMS attached to the meat with different freshness were collected to form a training source as the input of the convolutional neural network (CNN). Through convolving CMS color features, the meat freshness classified as “fresh”, “less fresh”, and “spoiled” was finally outputted. With the incorporation of CNN, the App enabled users to identify the freshness of meat from stored photos or real-time images of CMS-labeled meats in a fast, accurate, portable, and universal way. This visualized detection strategy of CMS combined with an algorithm-integrated App has a promising potential for wide applications such as food safety, health monitoring, and environmental protection.

Формы переноса РЗЭ фторидно-карбонатно-хлоридными охлаждающимися гидротермальными флюидами в присутствии барита и целестина (термодинамическое моделирование)

A thermodynamic study was carried out in order to determine the forms of transport for the entire series of lanthanides and their ratio with changing parameters of a hydrothermal fluid of moderate concentrations of chloride, carbonate and fluoride components. Hydrothermal solution, cooling from 500 to 100 ∘C, affected barite and celestine, which are used as a source of sulfate sulfur, monazite as a source of rare earth elements (REE) and phosphorus, and calcite as a source of calcium. It has been established that, under weakly acidic (pH about 4.1) conditions, the equilibrium mineral association is represented by rare earth fluorite, monazite, rare earth fluorapatite, and strontiobarite. In the high-temperature region for light and medium REE, the leading is the first chlorocomplex LnCl+2. For heavy REE, the second fluorine complex LnF+2 takes the first place, except for terbium and dysprosium, for which a sharp predominance of the sulfate complex is revealed. A special picture is observed at 100 ∘C: the leading position is occupied by Ln+3 for both light and heavy REE. In the case of a near neutral weakly alkaline fluid (pH about 7.1), the equilibrium mineral association is represented by calcite, monazite, REE-fluorite, REE-fluorapatite, strontiobarite, and strontianite. The appearance of the latter in natural associations may serve as an indication of the increased alkalinity of the ore-forming environment. In an equilibrium weakly alkaline fluid up to 200 ∘C, hydroxocomplexes are prevalent for all REEs with the ratio Ln(OH)03&gt; Ln(OH)+2. The first chloro complex for light REE at 500–400 ∘C, and the second fluoro complex for medium and heavy REEs follow them. At 100 ∘C, the concentration of hydroxocomplexes sharply decreases, and fluorine and carbonate complexes come to the fore. In general, there is an increased stability of the first chlorocomplex in the high-temperature region, and with decreasing temperature, the role of REE fluorocomplexes increases. Two variants of acidity-alkalinity calculations presumably correspond to modeling of two types of fluids: greisenizing – weakly acidic and carbonatite-forming – weakly alkaline.

Assessment of the pH value of the acid-base balance of&#x0D; the oral fluid in patients before the application of orthodontic&#x0D; devices, after three and six months of treatment&#x0D; with removable and non-removable equipment made of&#x0D; different materials

Hardware orthodontic treatment with intraoral devices&#x0D; made of various materials can contribute to the development&#x0D; of an imbalance of a number of chemical elements in the&#x0D; body, as well as their redistribution in the oral fluid. These&#x0D; changes affect the metabolic processes of both essential&#x0D; (vital) and toxic trace elements that can accumulate in the&#x0D; body, as well as affect the hydrogen pH of the oral fluid.&#x0D; Research objective. To investigate the hydrogen index of&#x0D; acid-base balance of oral fluid in patients before and during&#x0D; orthodontic treatment with various equipment in&#x0D; dynamics.

Gastric residual volume, safety, and effectiveness of drinking 250 mL of glucose solution 2-3 hours before surgery in gastric cancer patients: a multicenter, single-blind, randomized-controlled trial.

Carbohydrate drinking 2-3 hours before surgery has been widely adopted in colorectal operations. However, there is little direct evidence regarding its application in gastric cancer surgery. We aimed to evaluate the gastric residual volume, safety, and effectiveness of drinking 250 mL of 5% glucose solution 2-3 hours before elective gastric cancer surgery. We conducted an investigator-initiated, multicenter, randomized-controlled, parallel group, and equivalence trial. Eighty-eight patients with gastric adenocarcinoma were randomized into study or control group. Patients in the control group followed the traditional routine of 6-8 hours preoperative fasting, while those in the study group drank 250 mL of 5% glucose solution 2-3 hours before surgery. Immediately following tracheal intubation, gastric contents were aspirated through gastroscopy. The primary outcome was preoperative gastric residual volume. Eighty-three patients were eventually analysed in the study (42 in the study group and 41 in the control group). Two groups were comparable at baseline characteristics. There were no statistical differences in residual gastric fluid volumes (35.86 ± 27.13 vs 27.70 ± 20.37 mL, P = 0.135) and pH values (2.81 ± 1.99 vs 2.66 ± 1.68, P = 0.708) between the two groups. Preoperative discomfort was significantly more decreased in the study group than in the control group (thirst score: 1.49 ± 1.23 vs 4.14 ± 2.07, P < 0.001; hunger score: 1.66 ± 1.18 vs 3.00 ± 2.32, P = 0.007). There was no statistical difference in the incidence of postoperative complications (19.05% vs 17.07%, P = 0.815). Drinking 250 mL of 5% glucose solution 2-3 hours before surgery in elective gastric cancer patients shows benefits in lowering thirst and hunger scores without increasing gastric residual volume and perioperative complications.

Fossil hydrothermal oceanic systems through in-situ B isotopes in ophicarbonates (N. Apennines, Italy)

In submarine-hydrothermal systems, fluid-rock interactions play a pivotal role in fostering life on rocky planets. Carbonated-ultramafic rocks (i.e., ophicarbonates) represent an important witness of such environments and their study may provide new insights into hydrothermal processes. Here, we report in-situ trace element concentrations and the first in-situ boron isotope analyses (δ11B) of serpentines from the Ligurian N. Apennine (Italy) ophicarbonates, which represent non-subducted remnants of Jurassic ultramafic-hosted hydrothermal system. Based on micro-Raman analyses, lizardite is the dominant stable serpentine polymorph in the studied samples, thus constraining the temperature (T) of serpentinization below ca. 320 °C. By means of UPb LA-ICP-MS calcite geochronology, the age of the carbonation event is constrained at 137 ± 3 Ma (2σ, n = 52). The increasing inventory of several fluid-mobile elements (e.g., B, Li, As, Sb, Sr, U) associated with the REE budget variability in serpentines from ophicarbonates compared to those in pure serpentinites suggest that physico-chemical changes during the evolution of the hydrothermal system exert a relevant influence on the geochemistry of serpentines. Pure serpentinites, which are considered the protoliths of the ophicarbonates, show positive δ11B signatures from +15.8 to +35.0‰ (n = 24), thus falling in the range of present-day oceanic and forearc serpentinites and ophiolite-derived serpentinites. The δ11B imprint of serpentines in ophicarbonates clusters at +10.2 ± 2.2‰ (2SD, n = 57) and − 5.7 ± 1.5‰ (2SD, n = 36). Remarkably, this is the first report of oceanic serpentines showing negative B isotope compositions. The positive δ11B data likely reflect inheritance from the precursor serpentinite, while the negative δ11B values are here related to the hydrothermal process(es). We attempt to model how the variation in pH and different δ11B composition of the hydrothermal vent fluids (+25 and + 8‰) at different T (100 and 150 °C) can affect the δ11B imprint of serpentines. Our results indicate that either pH condition or δ11B of the hydrothermal vent fluids can shift the δ11B of serpentines from positive to negative values. Our new trace element and δ11B data are integrated and discussed with those from the literature to achieve new constraints in the variations and controls on the physical-chemical conditions of fluid-rock interaction during the progressive evolution of long-lived fossil ultramafic-hosted hydrothermal system. Finally, we discuss how subduction processes can potentially modify the B geochemistry of ophicarbonates and the information that we could achieve by studying B isotopes in such high-P lithologies to unravel the B- and C-cycles into the Earth's mantle since the onset of modern plate tectonics.

Comparison between Preoperative Overnight Fasting Versus Oral Rehydration Solution (ORS) Administration Until Two Hours before Abdominal Surgery Under General Anaesthesia

Background: Preoperative fasting is a major concern to protect the gastric aspiration which is very dangerous. However overnight fasting is uncomfortable and has many deleterious effects on the human body. In many countries fasting until 2 to 3 hours before surgery has been practiced but in Bangladesh, overnight fasting is still being practiced in routine cases.&#x0D; Objectives: The objective of this study was to compare the effectiveness between preoperative overnight fasting and oral rehydration solution administration until two hours before abdominal surgery under general anaesthesia.&#x0D; Methods: A total of 100 patients of ASA (American Society of Anesthesiologist) class I and II, age above 18 years, and BMI &lt; 30 kg/m2 were scheduled for abdominal surgery under GA (General Anaesthesia) were included in this study. Then all patients were randomized into two groups as patients who were on overnight fasting for 10 hours (Group A-Controlled, n=50), and patients who were on ORS until 2 hours before abdominal surgery (Group B-ORS, n=50). All patients had their last meal at 11 AM before the day of surgery. Patients in group A will not take anything orally or via any route, except their ongoing vital medications if present. Patients in group B received 500 ml of standard ORS in the early morning on the day of surgery after waking up from bed (from 05 AM to 06 AM) and another 500 ml until 2 hours before the surgery (06 AM to 07 AM). As the primary outcome gastric residual volume and gastric fluid pH in both group was measured immediately after anaesthesia induction. Several physiological measures (thirst and hunger, nausea/vomiting, cognitive function) were measured with the help of a preformed questionnaire.&#x0D; Results: Mean gastric residual volume immediately after induction was statistically significant (p&lt;0.05) between the two groups. However, the mean gastric fluid pH was statistically insignificant (p&gt;0.05). The ORS group (Group B) became less thirsty before surgery (P=0.001). Postoperative nausea/vomiting (PONV) was less in group B (P=0.029) than in group A. The patient’s recovery time was significantly less in ORS group (P=0.003). Postoperative cognitive performance was better in group B (P=0.001).&#x0D; Conclusions: Oral rehydration solution administration until two hours before surgery is effective and can be considered routinely before abdominal surgery conducted under general anaesthesia except for delayed gastric emptying.&#x0D; J Shaheed Suhrawardy Med Coll 2022; 14(1): 20-27

ANALISIS PENGARUH VARIASI HOLDING TIME ANNEALING TERHADAP LAJU KOROSI TITANIUM PADA LARUTAN CAIRAN TUBUH SINTETIS

Biomaterials are crucial for bone implants due to their biocompatible and inert nature, ensuring no adverse effects within the human body. Titanium is renowned for its exceptional corrosion resistance. This research aims to analyze the impact of annealing holding time and pH of synthetic body fluid on the hardness and corrosion rate of titanium. The annealing process was performed at 700°C, with holding times of 30, 60, and 90 minutes. As an electrolyte medium, a Hanks' solution with pH variations of 4, 6, and 8 was used and maintained at 37°C. Potentiodynamic corrosion testing demonstrated the lowest corrosion rate in specimens treated with 30 minutes of annealing at pH 8, measuring 0.32 x 10-2 mmpy. The 30-minute annealing exhibited the lowest corrosion rate, which was confirmed by Electrochemical Impedance Spectroscopy (EIS) results showing a higher Rp value, indicating a lower corrosion rate. This is attributed to the presence of a passive Rutile TiO2 layer formed during the annealing process, as confirmed by X-ray Diffraction (XRD) analysis. Metallography observations indicated that the microstructure of untreated specimens consisted of α and β phases. Scanning Electron Microscopy (SEM) analysis of specimens annealed for 30 minutes revealed an oxide layer on the surface without any visible pores. However, an increase in annealing holding time led to the formation of pores, particularly noticeable after 90 minutes of annealing. The presence of pores in the oxide layer resulted in an increased corrosion rate with longer annealing holding times. Conversely, hardness testing demonstrated that longer annealing holding times resulted in higher hardness values.