Concentrations Of Potassium Chloride Research Articles

Excess Potassium Promotes Autophagy to Maintain the Immunosuppressive Capacity of Myeloid-Derived Suppressor Cells Independent of Arginase 1.

Potassium ions (K+) are critical electrolytes that regulate multiple functions in immune cells. Recent studies have shown that the elevated concentration of extracellular potassium in the tumor interstitial fluid limits T cell effector function and suppresses the anti-tumor capacity of tumor-associated macrophages (TAMs). The effect of excess potassium on the biology of myeloid-derived suppressor cells (MDSCs), another important immune cell component of the tumor microenvironment (TME), is unknown. Here, we present data showing that increased concentrations of potassium chloride (KCl), as the source of K+ ions, facilitate autophagy by increasing the expression of the autophagosome marker LC3β. Simultaneously, excess potassium ions significantly decrease the expression of arginase I (Arg I) and inducible nitric oxide synthase (iNOS) without reducing the ability of MDSCs to suppress T cell proliferation. Further investigation reveals that excess K+ ions decrease the expression of the transcription factor C/EBP-β and alter the expression of phosphorylated kinases. While excess K+ ions downregulated the expression levels of phospho-AMPKα (pAMPKα), it increased the levels of pAKT and pERK. Additionally, potassium increased mitochondrial respiration as measured by the oxygen consumption rate (OCR). Interestingly, all these alterations induced by K+ ions were abolished by the autophagy inhibitor 3-methyladenine (3-MA). Our results suggest that hyperosmotic stress caused by excess K+ ions regulate the mitochondrial respiration and signaling pathways in MDSCs to trigger the process of autophagy to support MDSCs' immunosuppressive function by mechanisms independent of Arg I and iNOS. Overall, our in vitro and ex vivo findings offer valuable insights into the adaptations of MDSCs within the K+ ion-rich TME, which has important implications for MDSCs-targeted therapies.

Evaluation of the Nonlinear Response of KCl Solution to High-Amplitude Stimulation Using a Four-Point Cylindrical Gold Electrode.

A four-electrode system and high-voltage amplitude stimulation (with a voltage of more than 1 V) are always used for nonlinear spectroscopy of biological solutions like yeast suspension. Multiple studies indicate that yeast membrane activities are the primary source of the harmonics detected from yeast suspensions. However, other investigations have demonstrated that at least part of the harmonics are mainly due to the nonlinear impedance of the electrode-electrolyte interface. Here, we want to find a mathematical model to analyze the odd harmonics generated by the interface. The KCl solution is the basis of the essential medium used in yeast culture. No study models the nonlinear behavior of the KCl solution using four-electrode. We used a sinusoidal voltage with a low frequency and a high amplitude to test an ionic solution with 1, 30, and 130 mM of potassium chloride. The voltage had no direct current component. Here, we show that the relationship between the amplitude of the excitation voltage and the third harmonic of the current can be accurately represented using the Butler-Volmer equation. Additionally, we analyze the impact of potassium chloride (KCl) concentration on the behavior of the third harmonic. This paper presents a method and model that can be used for nonlinear spectroscopy studies of biological solutions using a four-electrode system with the aim of deriving information from cells without considering the interface effect.

The role of nanoparticle–surfactant interactions in air-stabilized foams used for improving oil recovery

Foam flooding, an emerging tertiary oil recovery technique, demonstrates efficacy as a conformance control method in enhanced oil recovery. Conformance control mitigates injected displacement fluid channeling and bypassing, improving macroscopic sweep efficiency. Generated foamed films preferentially enter high permeability zones, diverting subsequent injection into unswept lower permeability regions. Nanoparticle-reinforced foams exhibit consistent bulk stability and effective residual oil mobilization. This work utilizes dynamic foam analysis to probe the synergistic effects of zinc oxide nanoparticles and anionic surfactant on foam generation and persistence. Bulk and local scale foam stability is evaluated under various potassium chloride concentrations. Optimal foam stability occurs near the critical micelle concentration of the surfactant at 2,500 ppm. Increasing electrolyte concentration within a fixed surfactant formulation decreases foam stability due to salt-induced micellar swelling. An optimized electrolyte and nanoparticles with a surfactant combination produce high-quality foam with increased bubble density per unit area. Micellar swelling by nanoparticle adsorption inhibits lamellae thinning and liquid drainage. Enhanced foam properties improve microscopic displacement efficiency and mobility control in foam-assisted oil recovery. Oil recovery is increased by approximately 22% compared to conventional waterflooding.

Use of FRET-Sensor 'Mermaid' to Detect Subtle Changes in Membrane Potential of Primary Mouse PASMCs.

Subtle changes in the membrane potential of pulmonary arterial smooth muscle cells (PASMCs) are pivotal for controlling pulmonary vascular tone, e.g., for initiating Hypoxic Pulmonary Vasoconstriction, a vital mechanism of the pulmonary circulation. In our study, we evaluated the ability of the fluorescence resonance energy transfer (FRET)-based voltage-sensor Mermaid to detect such subtle changes in membrane potential. Mouse PASMCs were isolated and transduced with Mermaid-encoding lentiviral vectors before the acceptor/donor emission ratio was assessed via live cell FRET-imaging. Mermaid's sensitivity was tested by applying specific potassium chloride (KCl) concentrations. These KCl concentrations were previously validated by patch clamp recordings to induce depolarization with predefined amplitudes that physiologically occur in PASMCs. Mermaid's emission ratio dose-dependently increased upon depolarization with KCl. However, Mermaid formed unspecific intracellular aggregates, which limited the usefulness of this voltage sensor. When analyzing the membrane rim only to circumvent these unspecific signals, Mermaid was not suitable to resolve subtle changes in the membrane potential of ≤10 mV. In summary, we found Mermaid to be a suitable alternative for reliably detecting qualitative membrane voltage changes of more than 10 mV in primary mouse PASMCs. However, one should be aware of the limitations associated with this voltage sensor.

Evaluation of Short-Term Mussel Test for Estimating Toxicity.

Effect concentrations of ammonia, nickel, sodium chloride, and potassium chloride from short-term 7-day tests were compared to those from standard chronic 28-day toxicity tests with juvenile mussels (fatmucket, Lampsilis siliquoidea) to evaluate the sensitivities of the 7-day tests. The effect concentrations for nickel (59 µg Ni/L), chloride (316-519 mg Cl/L, a range from multiple tests), and potassium (15 mg K/L) obtained from the 7-day tests were within a range of effect concentrations for each corresponding chemical in the 28-day tests (41-91 µg Ni/L, 251->676 mg Cl/L, 15-23 mg K/L), whereas the 7-day ammonia effect concentration (0.40 mg/L total ammonia nitrogen; TAN) was up to 3.3-fold greater than the 28-day effect concentrations (0.12-0.36 mg TAN/L) but with overlapped 95% confidence limits. These results indicate that the 7-day tests produced similar estimates compared to the 28-day tests. Further studies are needed to evaluate the 7-day test sensitivity using additional chemicals with different modes of toxic action. Environ Toxicol Chem 2024;43:2020-2025. Published 2024. This article is a U.S. Government work and is in the public domain in the USA.

Analysis of swimming trajectories in Daphnia similis as an environmental impact assessment tool

Analysis of swimming trajectories in <i>Daphnia similis</i> as an environmental impact assessment tool

Vascular contraction of umbilical arteries of pregnant women with preeclampsia.

Potassium channels have an important role in the vascular adaptation during pregnancy and a reduction in the expression of adenosine triphosphate-sensitive potassium channels (Katp) has been linked to preeclampsia. Activation of Katp induces vasodilation; however, no previous study has been conducted to evaluate the effects of the inhibition of these channels in the contractility of preeclamptic arteries. Glibenclamide is an oral antihyperglycemic agent that inhibits Katp and has been widely used in vascular studies. To investigate the effects of the inhibition of Katp, umbilical arteries of preeclamptic women and women with healthy pregnancies were assessed by vascular contractility experiments, in the presence or absence of glibenclamide. The umbilical arteries were challenged with cumulative concentrations of potassium chloride (KCl) and serotonin. There were no differences between the groups concerning the maternal age and gestational age of the patients. The percentage of smokers, caucasians and primiparae per group was also similar. On the other hand, blood pressure parameters were elevated in the preeclamptic group. In addition, the preeclamptic group presented a significantly higher body mass index. The newborns of both groups presented similar APGAR scores and weights. In the presence of glibenclamide, there was an increase in the KCl-induced contractions only in vessels from the PE group, showing a possible involvement of these channels in the disorder.

Exploring Novel Sensor Design Ideas through Concentration-Induced Conformational Changes in PEG Single Chains

Polyethylene glycol (PEG) is an artificial polymer with good biocompatibility and a low cost, which has a wide range of applications. In this study, the dynamic response of PEG single chains to different ion concentrations was investigated from a microscopic point of view based on single-molecule force spectroscopy, revealing unique interactions that go beyond the traditional sensor-design paradigm. Under low concentrations of potassium chloride, PEG single chains exhibit a gradual reduction in rigidity, while, conversely, high concentrations induce a progressive increase in rigidity. This dichotomy serves as the cornerstone for a profound understanding of PEG conformational dynamics under diverse ion environments. Capitalizing on the remarkable sensitivity of PEG single chains to ion concentration shifts, we introduce innovative sensor-design ideas. Rooted in the adaptive nature of PEG single chains, these sensor designs extend beyond the traditional applications, promising advancements in environmental monitoring, healthcare, and materials science.

Experimental exploration of potassium compounds in the vicinity of a burning biomass pellet: From near-surface to downstream

The concentrations of gas-phase potassium hydroxide (KOH), potassium chloride (KCl) and atomic potassium (K(g)) were quantitatively measured from the near-surface to downstream area of burning pinewood pellets by a newly developed photofragmentation tunable diode laser absorption spectroscopy (PF-TDLAS) technique to reveal the original form of the released potassium. The novel arrangement of the PF-TDLAS system enabled a spatial resolution of ∼1 mm3, which made it possible to obtain temporal release profiles of K(g)/KOH/KCl at different heights above the burning pellet surface. Surface temperature and mass loss of the wood pellet as well as the gas temperature at measurement points were measured simultaneously. During the devolatilization stage, the release of all three potassium species was observed, with each of them accounting for ∼1/3; while in char oxidation stage, the release of KOH was dominant, but the release intensity was strongly influenced by the local oxygen content. The results from different measurement heights showed there was a notable difference in potassium release profiles of different potassium species over the near-surface area, where the detected potassium forms were the best representative of the originally released forms of potassium. For a period of time during the devolatilization stage, only K(g) was detected in the near-surface area, and the concentration was significantly lower than the downstream area where KOH and KCl coexisted. This suggested that a large amount of potassium might leave the pellet as organic-K, which cannot be detected by the PF-TDLAS method. During char oxidation stage, the total potassium concentration at the near-surface area was also lower than the downstream area, but it was due to the lack of oxygen at the measurement position. A potassium release mechanism during the devolatilization stage of biomass combustion was proposed based on the experimental measurements, and the results also indicated the importance of spatially resolved measurement.

Relaxant Effects of Piperine and Piperlongumine from Piper longum Fruits on Porcine Coronary Artery.

Since ancient times, Piper longum Linn. fruits have been recognized for exhibiting various effects, including the diaphoretic effects linked to enhanced blood flow. Piperine and piperlongumine coexist in Piper longum Linn. fruits, although the cardiovascular effects of both compounds remain elusive. We investigated their action of piperine and piperlongumine in porcine coronary arteries, comparing them to the Ca2+ channel antagonist diltiazem. Piperlongumine, unlike piperine or diltiazem, concentration-dependently inhibited basal contractile tone in endothelium-denuded coronary arteries. All three compounds inhibit tonic contractions induced by high potassium chloride (KCl) concentrations. The order of relaxation potency indexed by the half-maximal effective concentration (EC50) were as follows: diltiazem > piperlongumine > piperine. These effects were not different between endothelium-intact and -denuded preparations. In endothelial-denuded preparations, pretreatment with these compounds not only inhibited KCl-induced tonic contractions attenuated calcium chloride (CaCl2)-induced ones in a Ca2+-free medium. Histamine-induced phasic contractions in a Ca2+-free medium containing intracellular Ca2+ chelator was completely suppressed by selective inositol trisphosphate receptor antagonist and piperlongumine, whereas piperine or diltiazem do not have the same effect. These findings suggest that piperine and piperlongumine similar to diltiazem cause vasorelaxation by inhibiting both KCl- and CaCl2-induced contractions in coronary arteries, possibly through the inhibition of voltage-dependent Ca2+ channels. Piperlongumine inhibits histamine-induced contractions in a Ca2+-free medium, which is associated with the intracellular Ca2+ signaling pathway, suggesting that the relaxant effect of piperlongumine differs from that of piperine.

OPTIMIZATION OF KAPPA CARRAGEENAN POLYMER CONCENTRATION AND POTASSIUM CHLORIDE CROSSLINKER ON PHYSICAL CHARACTERISTICS OF GLUTATHIONE-KAPPA CARRAGEENAN NANOSPHERE

Objective: The objective of the study to obtain the most optimal physical characteristics of glutathione-kappa carrageenan nanosphere in terms of particle size, moisture content, yield, drug loading and entrapment efficiency.&#x0D; Methods: One of the drug delivery systems that can improve drug stability for antioxidants is nanosphere. Nanospheres were prepared using ionotropic gelation method with aerosol technique. This method is easy, fast, and relatively cost-effective to manufacture. This research was applied with optimization using a randomized full factorial design of 2² with differences in kappa carrageenan as polymer and potassium chloride concentrations as crosslinker. This study aims to obtain the most optimal physical characteristics of the nanosphere in terms of particle size, moisture content, yield, drug loading and entrapment efficiency.&#x0D; Results: The glutathione-kappa carrageenan nanosphere had particle sizes ranging from 247.03 to 675.07 nm with spherical and smooth nanosphere. Furthermore, the entrapment efficiency value ranged from 25.50–35.61%, and drug loading of 6.84–10.16%. The concentration of kappa polymer affected particle size, moisture content, entrapment efficiency, and drug loading. This indicated that higher polymer concentration resulted in greater particle size, moisture content, entrapment efficiency, and drug loading.&#x0D; Conclusion: The most optimal formula is F4 with 1% kappa-carrageenan concentration and 0.6% KCl.

Elemental composition of salt and vulnerability assessment of saline groundwater sources selected based on ethnoarchaeological evidence in Romania

The study aimed to evaluate the elemental composition of salt extracted from shallow to saline groundwater sources selected based on ethnoarchaeological evidence in the Eastern Carpathians and Sub-Carpathians area of Romania and to assess their specific vulnerability using groundwater pollution potential (DRASTIC and DRASTIC-LU methodology). 198 saline water samples were collected from different site types, including natural saline springs, catchment saline springs, brine wells, salted lakes and ponds, during the period between 2007 and 2019. Scanning electron microscopy with energy-dispersive X-ray spectroscopy was employed to characterize the elemental composition of salt after dry-evaporating a predetermined volume of each collected sample. The results indicated that the salt concentration in the brines ranged from 0.1% to 41.3%, with the highest concentration found in wells and natural saline springs. The dominant component was sodium chloride, but several sites had high concentrations of potassium chloride, which is essential for human health. Over 95% of the analyzed samples also contained other minerals like calcium and magnesium, further highlighting the health benefits of these brine sources. However, two sites were slightly contaminated with heavy metals, posing potential health risks if consumed. The DRASTIC index, a standardized system for evaluating groundwater pollution potential, gave scores between 99 and 208, indicating moderate to very high intrinsic pollution potential. Similarly, the DRASTIC-LU index, which takes into account and the land use aspects, showed scores ranging from 114 to 258, suggesting low to very high vulnerability to contamination. These findings provide valuable information on the elemental composition of salt and the vulnerability of these brine sources, which are still used by rural communities for traditional practices like meat and fish preservation, milk curdling, and pickling. The study has important implications for sustainable management from both ethnoarchaeological and economic perspectives.

Cost reduction in the construction of horizontal wells by optimizing the polymer-chloride drilling mud and its reuse

One of the key tasks in oil and gas well development today is to optimize the cost of various technical processes, including the preparation of drilling muds. The article explores technological remedies to decrease the concentration of potassium chloride, which is the main inhibitor of the hydration of clay rocks, in the composition of drilling mud used for horizontal well drilling. Additionally, it was demonstrated that the drilling mud left after the initial drilling of the productive formation could be reused. Due to the fact that the interval of the horizontal section of wells is represented mainly by sandstone, the composition of the drilling mud must be refined so that the use of inhibitor reagents can be reduced. Reuse of spent drilling muds in the construction of horizontal wells reduces the consumption of multi-tonnage components without impairing the processability of the flushing fluid used. The implementation of this approach will enable the achievement of economic benefits through a reduction in expenses for the preparation of drilling mud and in the amount of drilling waste generated.

A water-absorbent hydrogel prepared with arabinoxylans from flaxseed (Linum usitatissimum) and galactomannans from subabul (Leucaena leucocephala) impacts the growth and composition of cherry tomatoes in potted experiments

A water-absorbent hybrid hydrogel was prepared using arabinoxylans from flaxseed (Linum usitatissimum) (FX) and galactomannans from subabul (Leucaena leucocephala) (SG) in the presence of kappa-carrageenan (κC) with variable concentration of potassium chloride as crosslinker (0.01, 0.05, 0.1, 0.25 and 0.3 M), and evaluated on the basis of their swelling rate (%). The optimized hydrogel (GAXH) from a blend of SG, κC, FX and KCl at 5.5% w/v, 1.32% w/v, 1% w/v and 0.3M, respectively, showed 300% swelling in water at room temperature and pH 7.4 with 100% retention of water for 30 days at 10 °C. Blending 50% w/w GAXH in the soil could retain 140% water for 30 days, acting as a water reservoir in the soil system at 35 °C and pH 7.4 which reached 100% evaporation after 60 days. Incorporation of 50% w/w GAXH in sandy, loamy soil was used for the potted cultivation of cherry tomatoes (Solanum lycopersicum var. cerasiforme) and observed for growth and composition of the tomatoes. GAXH enhanced the physiological growth of both the plant as well as cherry tomatoes by controlling the release of KCl into the soil and maintaining soil moisture when 3 day intermittent watering schedule was used. An additional advantage was an improved water use efficiency and reduction in water footprint from 3.23 cm3/g to 9.32 cm3/g and 19.87 mL/fruit to 8.56 mL/fruit, respectively. The fully ripened tomatoes grown on GAXH-incorporated soil showed higher contents of lycopene, total carotenoids, and total polyphenols from 166 to 257 μg/g fresh weight, 99–107 mg β-carotene equivalent/100g fresh weight, 223–241 mg gallic acid equivalent/100 g fresh weight, respectively, than control cherry tomatoes grown in soil with no added GAXH. This was also reflected in enhanced antioxidant activity of cherry tomatoes grown in GAXH-incorporated soil.

Comparative inhibitory effects of sodium and potassium chloride salts on Staphylococcus aureus from fermented Pentaclethra macrophylla

Aim: The study was conducted to evaluate comparatively the individual effects of sodium (NaCl) and potassium (KCl) chloride salts against Staphylococcus aureus isolated from fermented Pentaclethra macrophylla. Method: A total of twenty (20) traditionally fermented food samples (Pentaclethra macrophylla) were purchased from a market in Umuahia metropolis. Isolation and identification of Staphylococcus aureus were conducted using standard microbiological techniques. Staphylococcus aureus was identified using standard morphological and biochemical tests. The inhibitory effect of both salts (NaCl and KCl) were analyzed on modified nutrient agar and nutrient broth (Media + 5% salt conc., Media + 10% salt conc., Media + 15% salt conc., Media + 20% salt conc.). The study measured culture growth using optical density readings at 425nm over 48 hours with different NaCl and KCl concentrations, while growth on plates was visually assessed on colony counter. Results: The highest optical density recorded as a result of contact with varying concentration of sodium chloride was 0.48 at 5% concentration after 48hours incubation while the least was 0.04 at 20% concentration after 12hours incubation while the highest optical density recorded as a result of contact with varying concentration of potassium chloride was 0.41 at 5% concentration after 48hours incubation while the least was 0.01 at 20% concentration after 12hours incubation. Conclusion: Higher salt concentrations resulted in osmotic shock, suppressing growth in Staphylococcus aureus, but increased salt concentration partially alleviated growth inhibition over time.

A superstable, flexible, and scalable nanofluidic ion regulation composite membrane

Two-dimensional layered membranes with high and stable ion transport properties have various applications in nanofluidic devices; however, their construction remains a considerable challenge. Herein, we develop a superstable aramid nanofiber/graphite composite membrane with numerous one-dimensional and two-dimensional nano-confined interspaces for ultrafast ion transport. The fabricated flexible and scalable membrane exhibits high tensile strength (∼115.3 MPa) even after immersion in water for 90 days. Further, the aramid nanofiber/graphite conductor features the surface-charge-governed ion transport behavior. The ionic conductivity of the membrane at a low potassium chloride concentration of 10−4 mol/L can be enhanced by 16 times that of the bulk counterpart. More importantly, its structure and ionic conductivity remain unchanged even after immersion in different harsh solutions (e.g., acid, base, and ethanol) for over 30 days. Molecular dynamics simulations reveal that the superstability of the membrane is attributable to the robust interchain interactions within the aramid nanofibers and the strong interfacial interactions between the aramid nanofibers and graphite nanosheets. This study highlights the superior structural stability of the proposed flexible and scalable aramid nanofiber/graphite composite membrane, which could be employed in advanced nanofluidic devices for application under extreme working environments.

Enhancing thermal stability and filtration control for water-based drilling fluid using viscosifier polymers and potassium chloride additives

Drilling operations conducted under high-pressure and high-temperature conditions present significant challenges for modern drilling advancements. Downhole temperatures can significantly impact the stability of water-based mud (WBM) properties, leading to costly issues and non-productive time resulting from drilling instabilities. To mitigate these issues, it is crucial to employ high-temperature-resistant additives in such operations. This study aimed to examine the influence of temperature on the stability of commonly used polymer types in water-based mud drilling operations. A series of laboratory experiments were conducted to investigate changes in normal mud properties following exposure to temperatures ranging from 79 to 350 °F. Two different mud polymers were used, including two viscosifier polymers (Flowzan - type A and Xanthan gum - type B), with varying concentrations of potassium chloride (KCl). Rheological analysis revealed that Polymer A exhibited superior performance as most mud properties, including viscosity, yield point, and gel strength, were significantly affected at different temperatures. However, plastic viscosities fell below the minimum recommended range of 8 cP for both polymers. At 250 °F, Polymer A's apparent viscosity of WBM was enhanced by 87%, 100%, and 120% with 3%, 5%, and 7% concentrations of KCl, respectively. For Polymer B, at 200 °F, it was improved by 118%, 112%, and 106%. The addition of KCl to the viscosifier polymers enhanced the thermal stability of the drilling fluid within the operating temperature range of 250–350 °F. Gel Point (10-min) remained below the recommended 35 lb/100 ft2 for all KCl concentrations of both polymers, while Gel Point (10-s) remained below the recommended 15 lb/100 ft2 for temperatures above 200 °F. Three other polymers were studied for filtration control without any KCl concentration, namely Bio Pac (type C), Mil Pac Xlo (type D), and Perma Loss (type E). Although API fluid loss remained below the recommended 15 cm3 for all the polymers, filtration control, and cake analysis demonstrated that Polymer C exhibited superior performance compared to the others. It also displayed thermal stability and cake thickness below the recommended 0.1 in up to temperatures below 250 °F. A novel sinusoidal correlation function is fit to experimental data, which can be used for training machine learning approaches.

A Nationwide Survey on Malaysian Hospital Physicians’ Practices of Intravenous Potassium Chloride Supplementation and Opinions on Premixed Formulation in the Treatment of Hypokalaemia

This study aims to evaluate the Malaysian hospital physicians’ practices of intravenous potassium chloride in the treatment of hypokalaemia and their opinions on using premixed formulation. This was a nationwide online survey using a self-administered questionnaire. The survey link was sent to the practising hospital physicians in Malaysia through email (n = 1,455), Facebook Messenger (n = 2,734) and posted on Facebook as well. A total of 207 responses were received. The physicians were mostly males (63.8%), aged between 30 years old–39 years old (51.2%) and worked in the government sectors (76.8%). The most preferred dosage of potassium chloride for mild, moderate and severe hypokalaemia was 10 mmol (44.4%), 20 mmol (55.1%) and 30 mmol (37.7%), respectively. The mostly chosen infusion rate of potassium chloride for mild hypokalaemia was over 24 h (41.1%) while for both moderate and severe hypokalaemia were over 1 h–2 h (63.8% and 89.9%, respectively). The concentration of intravenous potassium chloride is the main factor (68.1%) which would influence the infusion route choice. Serum potassium monitoring of every 24 h was chosen by 52.7% of the respondents for mild hypokalaemia while every 1 h–2 h was mostly chosen for moderate and severe hypokalaemia (49.3% and 87.4%, respectively). Cardiac monitoring was mostly opted in severe hypokalaemic patients (70.0%). Majority of physicians agreed that a premixed formulation is easier to administer (64.7%) and safer for the patients (51.7%). In conclusion, there were variations in the prescribing practices among Malaysian physicians to treat hypokalaemia. Most physicians were in favour of premixed formulation.

On-Chip Chemical Sensing Using Double-Slot Silicon Waveguide

In this article, we present refractive index measurement using a double-slot silicon waveguide-based Mach–Zehnder interferometer (MZI). We present a double-slot waveguide that offers the best sensitivity and limit of detection (LOD) compared to wire and single-slot waveguides. We demonstrate ultralow loss coupling between a single-mode waveguide and a double-slot waveguide and experimental proof for double-slot excitation. The double-slot waveguide is used to demonstrate a highly sensitive concentration sensor. An unbalanced Mach–Zehnder is used as the sensor device to demonstrate concentrations of potassium chloride (KCl) in deionized water. A sensitivity of 700 nm/RIU and a LOD of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.142\times 10^{-{6}}$ </tex-math></inline-formula> RIU are achieved experimentally. To the best of our knowledge, the demonstrated sensitivity is the highest for an ON-chip-guided waveguide sensing scheme. Index Double-slot waveguide, evanescent field, Mach–Zehnder interferometer (MZI), ON-chip, refractive index, sensitivity.

Smooth muscle contribution to vaginal viscoelastic response

Smooth muscle cells contribute to the mechanical function of various soft tissues, however, their contribution to the viscoelastic response when subjected to multiaxial loading remains unknown. The vagina is a fibromuscular viscoelastic organ that is exposed to prolonged and increased pressures with daily activities and physiologic processes such as vaginal birth. The vagina changes in geometry over time under prolonged pressure, known as creep. Vaginal smooth muscle cells may contribute to creep. This may be critical for the function of vaginal and other soft tissues that experience fluctuations in their biomechanical environment. Therefore, the objective of this study was to develop methods to evaluate the contribution of smooth muscle to vaginal creep under multiaxial loading using extension – inflation tests. The vaginas from wildtype mice (C57BL/6 × 129SvEv; 3–6 months; n = 10) were stimulated with various concentrations of potassium chloride then subjected to the measured in vivo pressure (7 mmHg) for 100 s. In a different cohort of mice (n = 5), the vagina was stimulated with a single concentration of potassium chloride then subjected to 5 and 15 mmHg. A laser micrometer measured vaginal outer diameter in real-time. Immunofluorescence evaluated the expression of alpha-smooth muscle actin and myosin heavy chain in the vaginal muscularis (n = 6). When smooth muscle contraction was activated, vaginal creep behavior increased compared to the relaxed state. However, increased pressure decreased the active creep response. This study demonstrated that extension – inflation protocols can be used to evaluate smooth muscle contribution to the viscoelastic response of tubular soft tissues.