β-Alanine Supplementation in Combat Sports: Evaluation of Sports Performance, Perception, and Anthropometric Parameters and Biochemical Markers-A Systematic Review of Clinical Trials

β-alanine does not have an ergogenic effect by itself, but it does as a precursor for the synthesis of carnosine in human skeletal muscle. β-alanine and carnosine together help improve the muscles' functionality, especially in high-intensity exercises such as combat sports. Therefore, β-alanine could be considered a nutritional ergogenic aid to improve sports performance in combat athletes. We aimed to critically review clinical trial evidence on the impact of β-alanine supplementation on sports performance, perception, and anthropometric parameters, as well as circulating biochemical markers in combat athletes. This systematic review was conducted following the specific methodological guidelines of the Preferred Report Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA), the PICOS question model, the Critical Review Form of McMaster, and the PEDro scale. Furthermore, the Cochrane risk-of-bias assessment tool was used. The search was carried out in the SCOPUS, Web of Science (WOS), and Medline (PubMed) databases for studies published from the beginning of the database until July 31, 2023. Of the 41 registers identified, only 7 met the established criteria and were included in this systematic review. Overall, performance parameters related to strength, power, total exercise work capacity, and combat-specific parameters were significantly improved (p < 0.05). Perception parameters increased non-significantly (p > 0.05). Regarding biochemical parameters, carnosine increased significantly (p < 0.05), pH decreased non-significantly (p > 0.05), and the results for blood bicarbonate and blood lactate were heterogeneous. Finally, there was a non-significant (p > 0.05) improvement in the anthropometric parameters of lean mass and fat mass. β-alanine supplementation appears to be safe and could be a suitable nutritional ergogenic aid for combat athletes.

Effect of Buffer Salts on Physical Stability of Lyophilized and Spray-Dried Protein Formulations Containing Bovine Serum Albumin and Trehalose

This study examined the effect of buffer salts on the physical stability of spray-dried and lyophilized formulations of a model protein, bovine serum albumin (BSA). BSA formulations with various buffers were dried by either lyophilization or spray drying. The protein powders were then characterized using solid-state Fourier transform infrared spectroscopy (ssFTIR), powder X-ray diffraction (PXRD), size exclusion chromatography (SEC), solid-state hydrogen/deuterium exchange with mass spectrometry (ssHDX-MS), and solid-state nuclear magnetic resonance spectroscopy (ssNMR). Particle characterizations such as Brunauer-Emmett-Teller (BET) surface area, particle size distribution, and particle morphology were also performed. Results from conventional techniques such as ssFTIR did not exhibit correlations with the physical stability of studied formulations. Deconvoluted peak areas of deuterated samples from the ssHDX-MS study showed a satisfactory correlation with the loss of the monomeric peak area measured by SEC (R2 of 0.8722 for spray-dried formulations and 0.8428 for lyophilized formulations) in the 90-day accelerated stability study conducted at 40°C. mDSC and PXRD was unable to measure phase separation in the samples right after drying. In contrast, ssNMR successfully detected the occurrence of phase separation between the succinic buffer component and protein in the lyophilized formulation, which results in a distribution of microenvironmental acidity and the subsequent loss of long-term stability. Moreover, our results suggested that buffer salts have less impact on physical stability for the spray-dried formulations than the lyophilized solids.

A step closer to continuous buffer preparation from solids: Predicting powder compaction and how to prevent it

The preparation of buffer solutions used in the biopharmaceutical industry is typically performed manually by the addition of one or multiple buffering reagents to water. Recently, the adaptation of powder feeders for continuous solid feeding was demonstrated for continuous buffer preparation. However, the intrinsic characteristics of powders can change the stability of the process, due to the hygroscopic nature of some substances and humidity induced caking and compaction behavior, but there is no simple and easy methodology available predicting this behavior for buffer species. To predict which buffering reagents are suitable without special precautions and investigate their behavior, force displacement measurements were conducted with a customized rheometer over 18hours. While most of the eight investigated buffering reagents indicated uniform compaction, especially sodium acetate and dipotassium hydrogen phosphate (K₂HPO₄) showed a significant increase in yield stress after 2hours. Experiments conducted with a 3D printed miniaturized screw conveyor confirmed the increased yield stress measurement by visible compaction and failure of the feeding. By taking additional precautions and adjusting the design of the hopper, we demonstrated a highly linear profile of all buffering reagents over a duration of 12 and 24hours. We showed that force displacement measurements accurately predict the behavior of buffer components in continuous feeding devices for continuous buffer preparation and are a valuable tool to identify buffer components that need special precautions. Stable, precise feeding of all tested buffer components was demonstrated, showing the importance of identifying buffers that need a specialized setup with a fast methodology.

Sulfate and acid-base balance

It has been acknowledged for years that compounds containing sulfur (S) are an important source of endogenous acid production. In the metabolism, S is oxidized to sulfate, and therefore the mEq sulfate excreted in the urine is counted as acid retained in the body. In this study we show that pH in fluids with constant [Na] and [HEPES] declines as sulfate ions are added, and we show that titratable acidity increases exactly with the equivalents of sulfate. Therefore, sulfate excretion in urine is also acid excretion per se. This is in accordance with the down-regulation of proximal sulfate reabsorption under acidosis and the observation that children with distal renal tubular acidosis may be sulfate depleted. These results are well explained using charge-balance modeling, which is based only on the three fundamental principles of electroneutrality, conservation of mass, and rules of dissociation as devised from physical chemistry. In contrast, the findings are in contrast to expectations from conventional narratives. These are unable to understand the decreasing pH as sulfate is added since no conventional acid is present. The results may undermine the traditional notion of endogenous acid production since in the case of sulfur balance, S oxidation and its excretion as sulfate exactly balance each other. Possible clinical correlates with these findings are discussed.

Strong ions and charge-balance

It has been shown that the ability to predict the pH in any chemically characterized fluid, together with its buffer-capacity and acid content can be based on the requirement of electroneutrality, conservation of mass, and rules of dissociation as provided by physical chemistry. More is not required, and less is not enough. The charge in most biological fluids is dominated by the constant charge on the completely dissociated strong ions but, nonetheless, a persistent narrative in physiology has problematized the notion that these have any role at all in acid-base homeostasis. While skepticism is always to be welcomed, some common arguments against the importance of strong ions are examined and refuted here. We find that the rejection of the importance of strong ions comes with the prize that even very simple systems such as fluids containing nothing else, or solutions of sodium bicarbonate in equilibrium with known tensions of CO₂ become incomprehensible. Importantly, there is nothing fundamentally wrong with the Henderson-Hasselbalch equation but the idea that it is sufficient to understand even simple systems is unfounded. What it lacks for a complete description is a statement of charge-balance including strong ions, total buffer concentrations, and water dissociation.

Neutralization Short-Circuiting with Weak Electrolytes Erodes the Efficiency of Bipolar Membranes

Bipolar membranes (BPMs) are critical components of a variety of electrochemical energy technologies. Many electrochemical applications require the use of buffers to maintain stable, nonextreme pH environments, yet the impact of buffers or weak acids/bases on the electrochemical behavior of BPMs remains poorly understood. Our data for a cell containing weak electrolytes is consistent with internal pH gradients within the anion exchange membrane (AEM) or cation exchange membrane (CEM) component of the BPM that form via ionic short-circuiting processes at open-circuit. Short-circuiting results from the coupling of co-ion crossover and parasitic neutralization and leads to buffering of the bipolar interface. This phenomenon, which we term neutralization short-circuiting, serves to erode BPM efficiency by attenuating the open-circuit membrane voltage and introducing parasitic reverse bias currents associated with weak acid/base dissociation at the interface. These findings establish a mechanistic basis for the operation of BPM cells in the presence of weak acid/base electrolytes.

Combined Distributed Shared-Buffered and Diagonally-Linked Mesh Topology for High-Performance Interconnect

Networks-on-Chip (NoCs) have become the de-facto on-chip interconnect for multi/manycore systems. A typical NoC router is made up of buffers used to store packets that are unable to advance to their desired destination. However, buffers consume significant power/area and are often underutilized, especially in cases of applications with non-uniform traffic patterns thus leading to performance degradation for such applications. To improve network performance, the Roundabout NoC (R-NoC) concept is considered. R-NoC is inspired by real-life multi-lane traffic roundabouts and consists of lanes that are shared by multiple input/output ports to maximize buffering resource utilization. R-NoC relies on router-internal adaptive routing that decides the lane path based on back pressure. Back pressure makes it possible to assess lane utilization and route packets accordingly. This is made possible thanks to the use of elastic buffers for control flow, a clever type of handshaking in a way similar to asynchronous circuits. Another prominent feature of R-NoC is that internal routing and arbitration are completely distributed which allows for significant freedom in deciding internal router topology and parameters. This work leverages this property and proposes novel yet unexplored configurations for which an in-depth evaluation of corresponding implementations on 45 nm CMOS technology is given. Each configuration is evaluated performance and power-wise on both synthetic and real application traffic. Several R-NoC configurations are identified and demonstrated to provide very significant performance improvements over standard mesh configurations and a typical input-buffered router, without compromising area and power consumption. Exploiting the distributed nature of R-NoC routers, a diagonally-linked configuration is then proposed which incurs moderate area overhead and features yet better performance and energy efficiency.

Non-carbonic buffer power of whole blood is increased in experimental metabolic acidosis: An in-vitro study

Non-carbonic buffer power (βNC) of blood is a pivotal concept in acid-base physiology as it is employed in several acid-base evaluation techniques, including the Davenport nomogram and the Van Slyke equation used for Base excess estimation in blood. So far, βNC has been assumed to be independent of metabolic acid-base status of blood, despite theoretical rationale for the contrary. In the current study, we used CO2 tonometry to assess βNC in blood samples from 10 healthy volunteers, simultaneously analyzing the electrolyte shifts across the red blood cell membrane as these shifts translate the action of intracellular non-carbonic buffers to plasma. The βNC of the blood was re-evaluated after experimental induction of metabolic acidosis obtained by adding a moderate or high amount of either hydrochloric or lactic acid to the samples. Moreover, the impact of βNC and pCO2 on the Base excess of blood was examined. In the control samples, βNC was 28.0 ± 2.5 mmol/L. In contrast to the traditional assumptions, our data showed that βNC rose by 0.36 mmol/L for each 1 mEq/l reduction in plasma strong ion difference (p < 0.0001) and was independent of the acid used. This could serve as a protective mechanism that increases the resilience of blood to the combination of metabolic and respiratory acidosis. Sodium and chloride were the only electrolytes whose plasma concentration changed relevantly during CO2 titration. Although no significant difference was found between the electrolyte shifts in the two types of acidosis, we observed a slightly higher rate of chloride change in hyperchloremic acidosis, while the variation of sodium was more pronounced in lactic acidosis. Lastly, we found that the rise of βNC in metabolic acidosis did not induce a clinically relevant bias in the calculation of Base excess of blood and confirmed that the Base excess of blood was little affected by a wide range of pCO2.

Acid content and buffer-capacity: a charge-balance perspective

Rational treatment and thorough diagnostic classification of acid-base disorders requires quantitative understanding of the mechanisms that generate and dissipate loads of acid and base. A natural precondition for this tallying is the ability to quantify the acid content in any specified fluid. Physical chemistry defines the pH-dependent charge on any buffer species, and also on strong ions on which, by definition, the charge is pH-invariant. Based, then, on the requirement of electroneutrality and conservation of mass, it was shown in 1914 that pH can be calculated and understood on the basis of the chemical composition of any fluid. Herein we first show that this specification for [H⁺] of the charge-balance model directly delivers the pH-dependent buffer-capacity as defined in the literature. Next, we show how the notion of acid transport as proposed in experimental physiology can be understood as a change in strong ion difference, ΔSID. Finally, based on Brønsted-Lowry theory we demonstrate that by defining the acid content as titratable acidity, this is equal to SID_ref - SID, where SID_ref is SID at pH 7.4. Thereby, any chemical situation is represented as a curve in a novel diagram with titratable acidity = SID_ref - SID as a function of pH. For any specification of buffer chemistry, therefore, the change in acid content in the fluid is path invariant. Since constituents of SID and titratable acidity are additive, we thereby, based on first principles, have defined a new framework for modeling acid balance across a cell, a whole organ, or the whole-body.

Rediscovery of 4-Trehalosamine as a Biologically Stable, Mass-Producible, and Chemically Modifiable Trehalose Analog

Nonreducing disaccharide trehalose is used as a stabilizer and humectant in various products and is a potential medicinal drug, showing curative effects on the animal models of various diseases. However, its use is limited as it is hydrolyzed by trehalase, a widely expressed enzyme in multiple organisms. Several trehalose analogs are prepared, including a microbial metabolite 4-trehalosamine, and their high biological stability is confirmed. For further analysis, 4-trehalosamine is selected as it shows high producibility. Compared with trehalose, 4-trehalosamine exhibits better or comparable protective activities and a high buffer capacity around the neutral pH. Another advantage of 4-trehalosamine is its chemical modifiability: simple reactions produce its various derivatives. Labeled probes and detergents are synthesized in one-pot reactions to exemplify the feasibility of their production, and their utility is confirmed for their respective applications. The labeled probes are used for mycobacterial staining. Although the derivative detergents can be effectively used in membrane protein research, long-chain detergents show 1000-3000-fold stronger autophagy-inducing activity in cultured cells than trehalose and are expected to become a drug lead and research reagent. These results indicate that 4-trehalosamine is a useful trehalose substitute for various purposes and a material to produce new useful derivative substances.

Light-Switchable Buffers

A visible light-switchable buffer system based on a merocyanine photoacid is presented. Para-substitution of the indolium side with a methoxy group affords a compound suitable for making hydrolytically stable aqueous buffers whose pH can be tuned between 7 and 4 using 500 nm light.

Low noncarbonic buffer power amplifies acute respiratory acid-base disorders in patients with sepsis: an in vitro study

Patients with sepsis have typically reduced concentrations of hemoglobin and albumin, the major components of noncarbonic buffer power (β). This could expose patients to high pH variations during acid-base disorders. The objective of this study is to compare, in vitro, noncarbonic β of patients with sepsis with that of healthy volunteers, and evaluate its distinct components. Whole blood and isolated plasma of 18 patients with sepsis and 18 controls were equilibrated with different CO₂ mixtures. Blood gases, pH, and electrolytes were measured. Noncarbonic β and noncarbonic β due to variations in strong ion difference (β_SID) were calculated for whole blood. Noncarbonic β and noncarbonic β normalized for albumin concentrations (β_NORM) were calculated for isolated plasma. Representative values at pH = 7.40 were compared. Albumin proteoforms were evaluated via two-dimensional electrophoresis. Hemoglobin and albumin concentrations were significantly lower in patients with sepsis. Patients with sepsis had lower noncarbonic β both of whole blood (22.0 ± 1.9 vs. 31.6 ± 2.1 mmol/L, P < 0.01) and plasma (0.5 ± 1.0 vs. 3.7 ± 0.8 mmol/L, P < 0.01). Noncarbonic β_SID was lower in patients (16.8 ± 1.9 vs. 24.4 ± 1.9 mmol/L, P < 0.01) and strongly correlated with hemoglobin concentration (r = 0.94, P < 0.01). Noncarbonic β_NORM was lower in patients [0.01 (-0.01 to 0.04) vs. 0.08 (0.06-0.09) mmol/g, P < 0.01]. Patients with sepsis and controls showed different amounts of albumin proteoforms. Patients with sepsis are exposed to higher pH variations for any given change in CO₂ due to lower concentrations of noncarbonic buffers and, possibly, an altered buffering function of albumin. In both patients with sepsis and healthy controls, electrolyte shifts are the major buffering mechanism during respiratory acid-base disorders.NEW & NOTEWORTHY Patients with sepsis are poorly protected against acute respiratory acid-base derangements due to a lower noncarbonic buffer power, which is caused both by a reduction in the major noncarbonic buffers, i.e. hemoglobin and albumin, and by a reduced buffering capacity of albumin. Electrolyte shifts from and to the red blood cells determining acute variations in strong ion difference are the major buffering mechanism during acute respiratory acid-base disorders.

Evaluation of the Stability of Bacteriophages in Different Solutions Suitable for the Production of Magistral Preparations in Belgium

In Belgium, the incorporation of phages into magistral preparations for human application has been permitted since 2018. The stability of such preparations is of high importance to guarantee quality and efficacy throughout treatments. We evaluated the ability to preserve infectivity of four different phages active against three different bacterial species in five different buffer and infusion solutions commonly used in medicine and biotechnological manufacturing processes, at two different concentrations (9 and 7 log pfu/mL), stored at 4 °C. DPBS without Ca²⁺ and Mg²⁺ was found to be the best option, compared to the other solutions. Suspensions with phage concentrations of 7 log pfu/mL were unsuited as their activity dropped below the effective therapeutic dose (6–9 log pfu/mL), even after one week of storage at 4 °C. Strong variability between phages was observed, with Acinetobacter baumannii phage Acibel004 being stable in four out of five different solutions. We also studied the long term storage of lyophilized staphylococcal phage ISP, and found that the titer could be preserved during a period of almost 8 years when sucrose and trehalose were used as stabilizers. After rehydration of the lyophilized ISP phage in saline, the phage solutions remained stable at 4 °C during a period of 126 days.

Tree Canopy Cover Is Best Associated with Perceptions of Greenspace: A Short Communication

A growing literature has supported a relationship between greenspace and health. Various greenspace metrics exist; some are based on subjective measures while others are based on an objective assessment of the landscape. While subjective measures may better reflect individual feelings about surrounding greenspace and the resulting positive benefits thereof, they are expensive and difficult to collect. In contrast, objective measures can be derived with relative ease, in a timely fashion, and for large regions and populations. While there have been some attempts to compare objective and subjective measures of greenspace, what is lacking is a comprehensive assessment of a wide range of greenspace metrics against subjective measures of greenspace. We performed such an assessment using a set of three objective greenspace metrics and a survey of residents in Liverpool, New South Wales, Australia. Our study supported existing findings in that overall, there is very little agreement between perceived and objective greenspace metrics. We also found that tree canopy in 10 min walking buffers around residences was the objective greenspace measure in best agreement with perceived greenspace.

Sodium Bicarbonate Supplementation Does Not Improve Running Anaerobic Sprint Test Performance in Semiprofessional Adolescent Soccer Players

Ergogenic strategies have been studied to alleviate muscle fatigue and improve sports performance. Sodium bicarbonate (NaHCO3) has improved repeated sprint performance in adult team-sports players, but the effect for adolescents is unknown. The aim of the present study was to evaluate the effect of NaHCO3 supplementation on repeated sprint performance in semiprofessional adolescent soccer players. In a double-blind, placebo-controlled, crossover trial, 15 male semiprofessional adolescent soccer players (15 ± 1 years; body fat 10.7 ± 1.3%) ingested NaHCO3 or a placebo (sodium chloride) 90 min before performing the running anaerobic sprint test (RAST). A countermovement jump was performed before and after the RAST, and ratings of perceived exertion, blood parameters (potential hydrogen and bicarbonate concentration), and fatigue index were also evaluated. Supplementation with NaHCO3 promoted alkalosis, as demonstrated by the increase from the baseline to preexercise, compared with the placebo (potential hydrogen: +0.07 ± 0.01 vs. -0.00 ± 0.01, p < .001 and bicarbonate: +3.44 ± 0.38 vs. -1.45 ± 0.31 mmol/L, p < .001); however, this change did not translate into an improvement in RAST total time (32.12 ± 0.30 vs. 33.31 ± 0.41 s, p = .553); fatigue index (5.44 ± 0.64 vs. 6.28 ± 0.64 W/s, p = .263); ratings of perceived exertion (7.60 ± 0.33 vs. 7.80 ± 0.10 units, p = .525); countermovement jump pre-RAST (32.21 ± 3.35 vs. 32.05 ± 3.51 cm, p = .383); or countermovement jump post-RAST (31.70 ± 0.78 vs. 32.74 ± 1.11 cm, p = .696). Acute NaHCO3 supplementation did not reduce muscle fatigue or improve RAST performance in semiprofessional adolescent soccer players. More work assessing supplementation in this age group is required to increase understanding in the area.

Health-Predictive Social-Environmental Stressors and Social Buffers Are Place Based: A Multilevel Example From San Bernardino Communities

Significant evidence demonstrates the powerful effects social determinants have on health-related perceptions, behaviors, and health outcomes. However, these factors are often studied out of context, despite the acknowledgement that social determinants of health are place based. This research aimed to demonstrate that health-related perceptions are dependent on where one lives. Via a community-based participatory study, participants were randomly selected from 3 residential regions varying distances from a freight railyard (nearest n = 300, middle n = 338, farthest n = 327), all mostly low-income, predominately Latino areas. Interview-administered surveys with adults were collected by bilingual trained community members (87% response) in English/Spanish. Adjusted-logistic regression models assessed residential region as a predictor of stressors (perceptions of community safety, community noise disturbance, health care access, food insecurity) and buffers (3 neighborhood cohesion variables), after adjusting for household income, race/ethnicity, gender, and age. Each region experienced a unique amalgam of stressors and buffers. In general, the region closest to the railyard experienced more stressors (odds ratio [OR] = 1.58; 95% CI 1.12-2.20) and less buffers (OR = 0.69; 95% CI 0.49-0.96) than the region furthest from the railyard. More than half of participants in each region reported 2 or more stressors and 2 or more buffers. In this seemingly homogenous study population, place remained important in spite of traditionally used socioeconomic factors, such as household income and race/ethnicity. Social determinants of health should be studied with regard to their environmental context, which will require interdisciplinary collaboration to improve multilevel research methods. Including the study of social buffers will also promote sustainable, positive change to reduce health disparities.

Modeling and simulation of spatial-temporal calcium distribution in T lymphocyte cell by using a reaction-diffusion equation

T lymphocytes are white blood cells that play a central role in cell-mediated immunity. Ca2+ has its major signaling function when it is elevated in the cytosolic compartment. The free cytosolic Ca2+ dynamics plays a very important role in the activation, and fate decision process in the T lymphocytes. Here, we develop a quantitative spatio-temporal Ca2+ dynamic model which includes, the Ca2+ releasing channels ER leak and voltage-gated Ca2+ channel, buffering and re-uptaking mechanism in the T lymphocytes. In this model, the cell is represented as a circular-shaped geometrical domain. This representation introduces modeling flexibility needed for detailed representation of the properties of Ca2+ dynamics in the cell including important parameters. The proposed mathematical model is solved using a finite difference method and the finite element method. Appropriate initial and boundary conditions are incorporated in the model based on biophysical conditions of the problem. Computer simulations in MATLAB R2010a are employed to investigate mathematical models of reaction-diffusion equation. The estimation is based on reaction-diffusion equation associated with biophysical and biochemical reactions taking place in the cell. From our results, it is observed that, the coordinated combination of the incorporated parameters plays a significant role in Ca2+ regulation in T lymphocytes. ER leak and voltage-gated Ca2+ channel provides the necessary Ca2+ to the cell when required for its proper functioning, while on the other side buffers and Na+/Ca2+ exchanger makes balance in the Ca2+ concentration, so as to prevent the cell from death as higher concentration for longer time is harmful for the cell and can cause cell death. These results have been used to study the relationship of Ca2+ concentration with parameters like VGCC, Na+/Ca2+ exchanger, ER leak and buffers. The significance of the study reveals that there is a significant variation in Ca2+ profiles due to the effect of VGCC, Na+/Ca2+ exchanger, ER leak, and buffers. The results give us better insights of coordinated effect of VGCC, Na+/Ca2+ exchanger, ER leak, and buffers on Ca2+ distribution in T lymphocytes. T lymphocytes are the primary host cells to receive the viral infections which transmits the signal then to other cell types. The proper quantity of Ca2+ concentration makes T lymphocytes more active and healthier to fight the infection properly and can protect the immune system from various fatal viral infections. Thus, the application of the study lies in the field of immunology to protect a susceptible from various viral infectious diseases like HIV, HBV, HINI, etc. by strengthening the immune system. The outcomes of the study reveal that the applied finite element method is computationally very strong and effective to analyze differential equations that arise in Ca2+ dynamics.

Calcium Buffering in the Heart in Health and Disease

Changes of intracellular Ca²⁺ concentration regulate many aspects of cardiac myocyte function. About 99% of the cytoplasmic calcium in cardiac myocytes is bound to buffers, and their properties will therefore have a major influence on Ca²⁺ signaling. This article considers the fundamental properties and identities of the buffers and how to measure them. It reviews the effects of buffering on the systolic Ca²⁺ transient and how this may change physiologically, and in heart failure and both atrial and ventricular arrhythmias, as well. It is concluded that the consequences of this strong buffering may be more significant than currently appreciated, and a fuller understanding is needed for proper understanding of cardiac calcium cycling and contractility.

How improving access times had unforeseen consequences: a case study in a Dutch hospital

OBJECTIVES

To investigate the consequences of increasing capacity to reduce access times, and to explore how patient waiting times and use of physical capacity were influenced by variability.

DESIGN

A retrospective case study that combines both primary and secondary data. Secondary data were retrieved from a hospital database to establish inflow and outflow of patients, utilisation of resources and available capacity, realised access times and the weekly number of new patients seen over 1 year. Primary data consisted of field notes, onsite visits and observations, and semistructured interviews.

SETTING

A secondary care facility, that is, a rheumatology department, in a large Dutch hospital.

PARTICIPANTS

Analyses are based on secondary patient data from the hospital database, and the responses of the interviews with physicians, nurses and Lean Six Sigma project leaders.

RESULTS

The study shows that artificial variability was increased by managerial decisions to add capacity and to allow an increased inflow of new patients. This, in turn, resulted in undesirable and significant fluctuations in access times. We argue that we witnessed a new multiplier effect that typifies the fluctuations.

CONCLUSIONS

Adding capacity resources to reduce access times might appear an obvious and effective solution. However, the outcomes were less straightforward than expected, and even led to new artificial variability. The study reveals a phenomenon that is specific to service environments, and especially healthcare, and has detrimental consequences for access times.

Changes in Ca2+ Removal Can Mask the Effects of Geometry During IP3R Mediated Ca2+ Signals

Calcium (Ca²⁺) signals are ubiquitous. Most intracellular Ca²⁺ signals involve the release of Ca²⁺ from the endoplasmic reticulum (ER) through Inositol 1,4,5-Trisphosphate Receptors (IP₃Rs). The non-uniform spatial organization of IP₃Rs and the fact that their individual openings are coupled via cytosolic Ca²⁺ are key factors for the variety of spatio-temporal distributions of the cytosolic [Ca²⁺] and the versatility of the signals. In this paper we combine experiments performed in untreated and in progesterone-treated Xenopus laevis oocytes and mathematical models to investigate how the interplay between geometry (the IP₃R spatial distribution) and dynamics (the processes that characterize the release, transport, and removal of cytosolic Ca²⁺) affects the resulting signals. Signal propagation looks more continuous and spatially uniform in treated (mature) than in untreated (immature) oocytes. This could be due to the different underlying IP₃R spatial distribution that has been observed in both cell types. The models, however, show that the rate of cytosolic Ca²⁺ removal, which is also different in both cell types, plays a key role affecting the coupling between Ca²⁺ release sites in such a way that the effect of the underlying IP₃R spatial distribution can be modified.

Enhanced Depolarization Drive in Failing Rabbit Ventricular Myocytes: Calcium-Dependent and β-Adrenergic Effects on Late Sodium, L-Type Calcium, and Sodium-Calcium Exchange Currents

BACKGROUND

Heart failure (HF) is characterized by electrophysiological remodeling resulting in increased risk of cardiac arrhythmias. Previous reports suggest that elevated inward ionic currents in HF promote action potential (AP) prolongation, increased short-term variability of AP repolarization, and delayed afterdepolarizations. However, the underlying changes in late Na+ current (INaL), L-type Ca2+ current, and NCX (Na+/Ca2+ exchanger) current are often measured in nonphysiological conditions (square-pulse voltage clamp, slow pacing rates, exogenous Ca2+ buffers).

METHODS

We measured the major inward currents and their Ca2+- and β-adrenergic dependence under physiological AP clamp in rabbit ventricular myocytes in chronic pressure/volume overload-induced HF (versus age-matched control).

RESULTS

AP duration and short-term variability of AP repolarization were increased in HF, and importantly, inhibition of INaL decreased both parameters to the control level. INaL was slightly increased in HF versus control even when intracellular Ca2+ was strongly buffered. But under physiological AP clamp with normal Ca2+ cycling, INaL was markedly upregulated in HF versus control (dependent largely on CaMKII [Ca2+/calmodulin-dependent protein kinase II] activity). β-Adrenergic stimulation (often elevated in HF) further enhanced INaL. L-type Ca2+ current was decreased in HF when Ca2+ was buffered, but CaMKII-mediated Ca2+-dependent facilitation upregulated physiological L-type Ca2+ current to the control level. Furthermore, L-type Ca2+ current response to β-adrenergic stimulation was significantly attenuated in HF. Inward NCX current was upregulated at phase 3 of AP in HF when assessed by combining experimental data and computational modeling.

CONCLUSIONS

Our results suggest that CaMKII-dependent upregulation of INaL in HF significantly contributes to AP prolongation and increased short-term variability of AP repolarization, which may lead to increased arrhythmia propensity, and is further exacerbated by adrenergic stress.

A Stable Metal-Organic Framework Featuring a Local Buffer Environment for Carbon Dioxide Fixation

A majority of metal-organic frameworks (MOFs) fail to preserve their physical and chemical properties after exposure to acidic, neutral, or alkaline aqueous solutions, therefore limiting their practical applications in many areas. The strategy demonstrated herein is the design and synthesis of an organic ligand that behaves as a buffer to drastically boost the aqueous stability of a porous MOF (JUC-1000), which maintains its structural integrity at low and high pH values. The local buffer environment resulting from the weak acid-base pairs of the custom-designed organic ligand also greatly facilitates the performance of JUC-1000 in the chemical fixation of carbon dioxide under ambient conditions, outperforming a series of benchmark catalysts.

Presentation matters: Buffers, packaging, and delivery devices for new, oral enteric vaccines for infants

Oral administration of vaccines is simpler and more acceptable than injection via needle and syringe, particularly for infants (Fig. 1) This route is promising for new vaccines in development against enterotoxigenic Escherichia coli (ETEC) and Shigella that cause childhood diarrhea with devastating consequences in low-resource countries. However, vaccine antigens and adjuvants given orally need buffering against the degradative effects of low stomach pH, and the type and volume of antacid buffer require special attention for infants. In addition, container/closure systems must be compatible with vaccine formulations, protect against water and gas transfer, and have minimal impact on the cold chain. Health care workers in demanding low-resource settings need an administration device that is easy to use, yet will accurately measure and safely deliver the correct vaccine dose. Developers must consider manufacturing capabilities, and immunization program managers want affordable vaccines. As new combination enteric vaccine candidates advance into clinical evaluation, features of the final vaccine presentation-liquid or dry format, diluent, buffer, primary and secondary packaging, and administration device-should be taken into account early in product development to achieve the greatest possible impact for the vaccine.

Within What Distance Does "Greenness" Best Predict Physical Health? A Systematic Review of Articles with GIS Buffer Analyses across the Lifespan

Is the amount of "greenness" within a 250-m, 500-m, 1000-m or a 2000-m buffer surrounding a person's home a good predictor of their physical health? The evidence is inconclusive. We reviewed Web of Science articles that used geographic information system buffer analyses to identify trends between physical health, greenness, and distance within which greenness is measured. Our inclusion criteria were: (1) use of buffers to estimate residential greenness; (2) statistical analyses that calculated significance of the greenness-physical health relationship; and (3) peer-reviewed articles published in English between 2007 and 2017. To capture multiple findings from a single article, we selected our unit of inquiry as the analysis, not the article. Our final sample included 260 analyses in 47 articles. All aspects of the review were in accordance with PRISMA guidelines. Analyses were independently judged as more, less, or least likely to be biased based on the inclusion of objective health measures and income/education controls. We found evidence that larger buffer sizes, up to 2000 m, better predicted physical health than smaller ones. We recommend that future analyses use nested rather than overlapping buffers to evaluate to what extent greenness not immediately around a person's home (i.e., within 1000-2000 m) predicts physical health.

Mitigating the impact of oil-palm monoculture on freshwater fishes in Southeast Asia

Anthropogenic land-cover change is driving biodiversity loss worldwide. At the epicenter of this crisis lies Southeast Asia, where biodiversity-rich forests are being converted to oil-palm monocultures. As demand for palm oil increases, there is an urgent need to find strategies that maintain biodiversity in plantations. Previous studies found that retaining forest patches within plantations benefited some terrestrial taxa but not others. However, no study has focused on aquatic taxa such as fishes, despite their importance to human well-being. We assessed the efficacy of forested riparian reserves in conserving freshwater fish biodiversity in oil-palm monoculture by sampling stream fish communities in an oil-palm plantation in Central Kalimantan, Indonesia. Forested riparian reserves maintained preconversion local fish species richness and functional diversity. In contrast, local and total species richness, biomass, and functional diversity declined markedly in streams without riparian reserves. Mechanistically, riparian reserves appeared to increase local species richness by increasing leaf litter cover and maintaining coarse substrate. The loss of fishes specializing in leaf litter and coarse substrate decreased functional diversity and altered community composition in oil-palm plantation streams that lacked riparian reserves. Thus, a land-sharing strategy that incorporates the retention of forested riparian reserves may maintain the ecological integrity of fish communities in oil-palm plantations. We urge policy makers and growers to make retention of riparian reserves in oil-palm plantations standard practice, and we encourage palm-oil purchasers to source only palm oil from plantations that employ this practice.

Evidence from mathematical modeling that carbonic anhydrase II and IV enhance CO2 fluxes across Xenopus oocyte plasma membranes

Exposing an oocyte to CO2/HCO3 (-) causes intracellular pH (pHi) to decline and extracellular-surface pH (pHS) to rise to a peak and decay. The two companion papers showed that oocytes injected with cytosolic carbonic anhydrase II (CA II) or expressing surface CA IV exhibit increased maximal rate of pHi change (dpHi/dt)max, increased maximal pHS changes (ΔpHS), and decreased time constants for pHi decline and pHS decay. Here we investigate these results using refinements of an earlier mathematical model of CO2 influx into a spherical cell. Refinements include 1) reduced cytosolic water content, 2) reduced cytosolic diffusion constants, 3) refined CA II activity, 4) layer of intracellular vesicles, 5) reduced membrane CO2 permeability, 6) microvilli, 7) refined CA IV activity, 8) a vitelline membrane, and 9) a new simulation protocol for delivering and removing the bulk extracellular CO2/HCO3 (-) solution. We show how these features affect the simulated pHi and pHS transients and use the refined model with the experimental data for 1.5% CO2/10 mM HCO3 (-) (pHo = 7.5) to find parameter values that approximate ΔpHS, the time to peak pHS, the time delay to the start of the pHi change, (dpHi/dt)max, and the change in steady-state pHi. We validate the revised model against data collected as we vary levels of CO2/HCO3 (-) or of extracellular HEPES buffer. The model confirms the hypothesis that CA II and CA IV enhance transmembrane CO2 fluxes by maximizing CO2 gradients across the plasma membrane, and it predicts that the pH effects of simultaneously implementing intracellular and extracellular-surface CA are supra-additive.

Developing suitable buffers to capture transport cycling behavior

The association between neighborhood built environment and cycling has received considerable attention in health literature over the last two decades, but different neighborhood definitions have been used and it is unclear which one is most appropriate. Administrative or fixed residential spatial units (e.g., home-buffer-based neighborhoods) are not necessarily representative for environmental exposure. An increased understanding of appropriate neighborhoods is needed. GPS cycling tracks from 78 participants for 7 days form the basis for the development and testing of different neighborhood buffers for transport cycling. The percentage of GPS points per square meter was used as indicator of the effectiveness of a series of different buffer types, including home-based network buffers, shortest route to city center buffers, and city center-directed ellipse-shaped buffers. The results show that GPS tracks can help us understand where people go and stay during the day, which can help us link built environment with cycling. Analysis showed that the further people live from the city center, the more elongated are their GPS tracks, and the better an ellipse-shaped directional buffer captured transport cycling behavior. In conclusion, we argue that in order to be able to link built environment factors with different forms of physical activity, we must study the most likely area people use. In this particular study, to capture transport cycling, with its relatively large radius of action, city center-directed ellipse-shaped buffers yielded better results than traditional home-based network buffer types. The ellipse-shaped buffer types could therefore be considered an alternative to more traditional buffers or administrative units in future studies of transport cycling behavior.

Buffer Standards for the Physiological pH of N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine (TRICINE) from T = (278.15 to 328.15) K

The pH values of two buffer solutions without NaCl and seven buffer solutions with added NaCl, having ionic strengths (I = 0.16 mol·kg(-1)) similar to those of physiological fluids, have been evaluated at 12 temperatures from T = (278.15 to 328.15) K by way of the extended form of the Debye-Hückel equation of the Bates-Guggenheim convention. The residual liquid junction potentials (δE(j)) between the buffer solutions of TRICINE and saturated KCl solution of the calomel electrode at T = (298.15 and 310.15) K have been estimated by measurement with a flowing junction cell. For the buffer solutions with the molality of TRICINE (m(1)) = 0.06 mol·kg(-1), NaTRICINE (m(2)) = 0.02 mol·kg(-1), and NaCl (m(3)) = 0.14 mol·kg(-1), the pH values at 310.15 K obtained from the extended Debye-Hückel equation and the inclusion of the liquid junction correction are 7.342 and 7.342, respectively. These are in excellent agreement. The zwitterionic buffer TRICINE is recommended as a secondary pH standard in the region for clinical application.

Buffer standards for the physiological pH of the zwitterionic compound of 3-(N-morpholino)propanesulfonic acid (MOPS) from T = (278.15 to 328.15) K

This paper reports the pH values of five NaCl-free buffer solutions and eleven buffer compositions containing NaCl at I = 0.16 mol·kg(-1). Conventional pa(H) values are reported for sixteen buffer solutions with and without NaCl salt. The operational pH values have been calculated for five buffer solutions and are recommended as pH standards at T = (298.15 and 310.15) K after correcting the liquid junction potentials. For buffer solutions with the composition m(1) = 0.04 mol·kg(-1), m(2) = 0.08 mol·kg(-1), m(3) = 0.08 mol·kg(-1) at I = 0.16 mol·kg(-1), the pH at 310.15 K is 7.269, which is close to 7.407, the pH of blood serum. It is recommended as a pH standard for biological specimens.

Buffer Standards for the Physiological pH of the Zwitterionic Compound, DIPSO from 5 to 55 degrees C

The values of the second dissociation constant, pK(2), and related thermodynamic quantities of 3-[N,N-bis (2-hydroxyethyl)amino]-2-hydroxypropanesulfonic acid (DIPSO) have already been reported over the temperature range 5 to 55 degrees C including 37 degrees C. This paper reports the pH values of four NaCl-free buffer solutions and four buffer composition containing NaCl salt at I = 0.16 mol.kg(-1). Conventional pa(H) values are reported for all eight buffer solutions. The operational pH values have been calculated for four buffer solutions recommended as pH standards, at 25 and 37 degrees C after correcting the liquid junction potentials with the flowing junction cell.

Buffer Standards for pH Measurement of N-(2-Hydroxyethyl)piperazine-N'-2-ethanesulfonic Acid (HEPES) for I = 0.16 mol.kg from 5 to 55 degrees C

The values of the second dissociation constant, pK(2) of N-(2-hydroxyethyl) piperazine-N'-2-ethanesulfonic acid (HEPES) have been reported at 12 temperatures over the temperature range 5 to 55 degrees C, including 37 degrees C. This paper reports the results for the pa(H) of eight isotonic saline buffer solutions with an I = 0.16 mol*kg(-1) including compositions: (a) HEPES (0.01 mol*kg(-1)) + NaHEPES (0.01 mol*kg(-1)) + NaCl (0.15 mol*kg(-1)); (b) HEPES (0.02 mol*kg(-1)) + NaHEPES (0.02 mol*kg(-1)) + NaCl (0.14 mol*kg(-1)); (c) HEPES (0.03 mol*kg(-1)) + NaHEPES (0.03 mol*kg(-1)) + NaCl (0.13 mol*kg(-1)); (d) HEPES (0.04 mol*kg(-1)) + NaHEPES (0.04 mol*kg(-1)) + NaCl (0.12 mol*kg(-1)); (e) HEPES (0.05 mol*kg(-1)) + NaHEPES (0.05 mol*kg(-1)) + NaCl (0.11 mol*kg(-1)); (f) HEPES (0.06 mol*kg(-1)) + NaHEPES (0.06 mol*kg(-1)) + NaCl (0.10 mol*kg(-1)); (g) HEPES (0.07 mol*kg(-1)) + NaHEPES (0.07 mol*kg(-1)) + NaCl (0.09 mol*kg(-1)); and (h) HEPES (0.08 mol*kg(-1)) + NaHEPES (0.08 mol*kg(-1)) + NaCl (0.08 mol*kg(-1)). Conventional pa(H) values, for all eight buffer solutions from 5 to 55 degrees C have been calculated. The operational pH values with liquid junction corrections, at 25 and 37 degrees C have been determined based on the NBS/NIST standard between the physiological phosphate standard and four buffer solutions. These are recommended as pH standards for physiological fluids in the range of pH 7.3 to 7.5 at I = 0.16 mol*kg(-1).

Environmental management: integrating ecological evaluation, remediation, restoration, natural resource damage assessment and long-term stewardship on contaminated lands

Ecological evaluation is essential for remediation, restoration, and Natural Resource Damage Assessment (NRDA), and forms the basis for many management practices. These include determining status and trends of biological, physical, or chemical/radiological conditions, conducting environmental impact assessments, performing remedial actions should remediation fail, managing ecosystems and wildlife, and assessing the efficacy of remediation, restoration, and long-term stewardship. The objective of this paper is to explore the meanings of these assessments, examine the relationships among them, and suggest methods of integration that will move environmental management forward. While remediation, restoration, and NRDA, among others, are often conducted separately, it is important to integrate them for contaminated land where the risks to ecoreceptors (including humans) can be high, and the potential damage to functioning ecosystems great. Ecological evaluations can range from inventories of local plants and animals, determinations of reproductive success of particular species, levels of contaminants in organisms, kinds and levels of effects, and environmental impact assessments, to very formal ecological risk assessments for a chemical or other stressor. Such evaluations can range from the individual species to populations, communities, ecosystems or the landscape scale. Ecological evaluations serve as the basis for making decisions about the levels and kinds of remediation, the levels and kinds of restoration possible, and the degree and kinds of natural resource injuries that have occurred because of contamination. Many different disciplines are involved in ecological evaluation, including biologists, conservationists, foresters, restoration ecologists, ecological engineers, economists, hydrologist, and geologists. Since ecological evaluation forms the basis for so many different types of environmental management, it seems reasonable to integrate management options to achieve economies of time, energy, and costs. Integration and iteration among these disciplines is possible only with continued interactions among practitioners, regulators, policy-makers, Native American Tribes, and the general public.

A versatile electrophoresis system for the analysis of high- and low-molecular-weight proteins

A new, versatile, multiphasic buffer system for high-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins in the relative molecular weight range of 300 000-3000 Da is described. The system, based on the theory of multiphasic zone electrophoresis, allows complete stacking and destacking of proteins in the above M(r) range. The buffer system uses taurine and chloride as trailing and leading ion, respectively, and Tris, at a pH close to its pK(a), as the buffering counterion. Coupled with limited variation in the acrylamide concentration, this electrophoresis system allows to tailor the resolution in the 6-200 kDa M(r) range, with minimal difficulties in the post electrophoretic identification processes.

A Report on the National Bureau of Standards pH Standards

In 1980, the research program in pH was re-established at the National Bureau of Standards (NBS). This report describes the state of this research, as well as the state of the NBS pH standards. The thermodynamic definition and the determination of pH are elaborated. The problems of liquid junction potentials encountered in the practical determination of pH are discussed. The goal of the research program in pH is to develop and maintain a unified pH scale based on clearly stated thermodynamic criteria, with a wide range of applicability to practical pH measurements.