Rapid Volume Changes Research Articles

The heart as a spring, the measurement of myocardial bounce to assess left ventricular function on cardiac MR.

Little has been reported on the left ventricular myocardial distension (bounce) and its utility to assess cardiac function. The purpose of this study is to determine whether myocardial bounce at end diastole is reproducibly visualized by blinded observers and to determine whether it corresponds to systolic and diastolic function. 144 Consecutive cardiac MR exams between September and December 2017 were selected for analysis. The bounce was graded by two blinded observers, and the change in LV diameter pre and post bounce was measured. The bounce was defined as the rapid change in LV volume that occurs at the end of diastole during atrial contraction just prior to systolic ejection. Inter-reader agreement was summarized using Cohen's kappa. Spearman's rank correlation coefficient was used to evaluate associations between bounce grade and cardiac physiology parameters. Overall agreement was good with unweighted kappa = 0.69 (95% CI 0.60-0.79). Bounce grade was significantly correlated with the average change in LV diameter before and after the bounce (Spearman's rho = 0.76, p < 0.001). Median diameter changes were 0.0, 1.9, and 4.2mm in grades 0 (no bounce), 1 (small bounce), and 2 (normal), respectively. The bounce lasted 8 to 12ms in all patients. Bounce grade was significantly correlated with LV EF (Spearman's rho = 0.43, p < 0.001). Median EF was 44%, 51%, and 58% in grades 0, 1, and 2, respectively. Of the 87 patients who had E/A ratio or E/e' ratio measured, bounce grade was also significantly correlated with E/A ratio (r = - 0.24, p = 0.034) and E/e' ratio (r = - 0.24, p = 0.022), with lower grades having higher ratio values on average (Table 4). Of the 15 patients with a bounce grade of 0 by one or both readers and EF ≥ 50%, 8 had E/A ratio measurements and 7 had E/e' ratio measurements. The E/A ratio values ranged from 1 to 2.7 (median 1.5). The E/e' ratio values ranged from 4.8 to 9.6 (median 7.7). The simple observation of a normal myocardial bounce during cine loop review of cardiac MR exams was predictive of normal diastolic and systolic cardiac function. Lack of myocardial bounce was highly associated with both systolic and diastolic dysfunction. The subpopulation of patients with loss of myocardial bounce and normal ejection fraction appear to represent patients with early diastolic dysfunction. Further studies with more diastolic dysfunction MRs are needed to examine this relationship. This study suggests changes to the myocardial bounce seen on cardiac MR may be a simple useful tool for detecting cardiac dysfunction. This study is not to replace, but rather aid the clinical diagnosis and management of both diastolic and systolic dysfunction.

The Trifecta of Tele-Critical Care: Intrahospital, Operational, and Mass Casualty Applications

Tele-critical care (TCC) has improved outcomes in civilian hospitals and military treatment facilities (MTFs). Tele-critical care has the potential to concurrently support MTFs and operational environments and could increase capacity and capability during mass casualty events. TCC services distributed across multiple hub sites may flexibly adapt to rapid changes in patient volume and complexity to fully optimize resources. Given the highly variable census in MTF intensive care units (ICU), the proposed TCC solution offers system resiliency and redundancy for garrison, operational, and mass casualty needs, while also maximizing return on investment for the Defense Health Agency. The investigators piloted simultaneous TCC support to the MTF during three field exercises: (1) TCC concurrently monitored the ICU during a remote mass casualty exercise: the TCC physician monitored a high-risk ICU patient while the nurse monitored 24 simulated field casualties; (2) TCC concurrently monitored the garrison ICU and a remote military medical field exercise: the physician provided tele-mentoring during prolonged field care for a simulated casualty, and the nurse provided hospital ICU TCC; (3) the TCC nurse simultaneously monitored the ICU while providing reach-back support to field hospital nurses training in a simulation scenario. TCC proved feasible during multiple exercises with concurrent tele-mentoring to different care environments including physician and nurse alternating operational and hospital support roles, and an ICU nurse managing both simultaneously. ICU staff noted enhanced quality and safety of bedside care. Field exercise participants indicated TCC expanded multipatient monitoring during mass casualties and enhanced novice caregiver procedural capability and scope of patient complexity. Tele-critical care can extend critical care services to anywhere at any time in support of garrison medicine, operational medicine, and mass casualty settings. An interoperable, flexibly staffed, and rapidly expandable TCC network must be further developed given the potential for large casualty volumes to overwhelm a single TCC provider with multiple duties. Lessons learned from development of this capability should have applicability for managing military and civilian mass casualty events.

Rapid and reversible cell volume changes in response to osmotic stress in yeast.

Saccharomyces cerevisiae has evolved diverse mechanisms to osmotic changes: the cell wall, ion and water transport systems, and signaling cascades. At the present time, little is known about the mechanisms involved in short-term responses of osmotic stress in yeast or their physiological state during this process. We conducted studies of flow cytometry, wet weight measurements, and electron microscopy to evaluate the modifications in cell volume and the cell wall induced by osmotic stress. In response to osmotic challenges, we show very fast and drastic changes in cell volume (up to 60%), which were completed in less than eight seconds. This dramatic change was completely reversible approximately 16s after returning to an isosmotic solution. Cell volume changes were also accompanied by adaptations in yeast metabolism observed as a reduction by 50% in the respiratory rate, measured as oxygen consumption. This effect was also fully reversible upon returning to an isosmotic solution. It is noteworthy that we observed a significant recovery in oxygen consumption during the first 10min of the osmotic shock. The rapid adjustment of the cellular volume may represent an evolutionary advantage, allowing greater flexibility for survival.

A high efficiency electrolyte enables robust inorganic–organic solid electrolyte interfaces for fast Li metal anode

Developing a high-rate Li metal anode with superior reversibility is a prerequisite for fast-charging Li metal batteries. However, the build-up of large concentration gradients under high current density leads to inhomogeneous Li deposition and unstable passivation layers of Li metal, resulting in lower Coulombic efficiency. Here we report a concentrated dual-salts LiFSI-LiNO3/DOL electrolyte to improve the high-rate performance of Li metal anode. Sufficient Li salts help passivate the fresh Li deposition quickly. Further, DOL contributes to the formation of flexible organic layers that can accommodate the rapid volume change of Li metal upon cycling. Li metal in the electrolyte remains stable over 240 cycles with the average Coulombic efficiency of 99.14% under a high current density of 8.0 mA cm−2.

Abnormal neonatal sodium handling in skin precedes hypertension in the SAME rat

We discovered high Na+ and water content in the skin of newborn Sprague–Dawley rats, which reduced ~ 2.5-fold by 7 days of age, indicating rapid changes in extracellular volume (ECV). Equivalent changes in ECV post birth were also observed in C57Bl/6 J mice, with a fourfold reduction over 7 days, to approximately adult levels. This established the generality of increased ECV at birth. We investigated early sodium and water handling in neonates from a second rat strain, Fischer, and an Hsd11b2-knockout rat modelling the syndrome of apparent mineralocorticoid excess (SAME). Despite Hsd11b2−/− animals exhibiting lower skin Na+ and water levels than controls at birth, they retained ~ 30% higher Na+ content in their pelts at the expense of K+ thereafter. Hsd11b2−/− neonates exhibited incipient hypokalaemia from 15 days of age and became increasingly polydipsic and polyuric from weaning. As with adults, they excreted a high proportion of ingested Na+ through the kidney, (56.15 ± 8.21% versus control 34.15 ± 8.23%; n = 4; P < 0.0001), suggesting that changes in nephron electrolyte transporters identified in adults, by RNA-seq analysis, occur by 4 weeks of age. Our data reveal that Na+ imbalance in the Hsd11b2−/− neonate leads to excess Na+ storage in skin and incipient hypokalaemia, which, together with increased, glucocorticoid-induced Na+ uptake in the kidney, then contribute to progressive, volume contracted, salt-sensitive hypertension. Skin Na+ plays an important role in the development of SAME but, equally, may play a key physiological role at birth, supporting post-natal growth, as an innate barrier to infection or as a rudimentary kidney.

Short-Term Prediction Model of Postal Parcel Traffic based on Self-Similarity

Postal logistics organizations are characterized as having high labor intensity and short response times. These characteristics, along with rapid change in mail volume, make load scheduling a fundamental concern. Load analysis of major postal infrastructures such as post offices, sorting centers, exchange centers, and delivery stations is required for optimal postal logistics operation. In particular, the performance of mail traffic forecasting is essential for optimizing the resource operation by accurate load analysis. This paper addresses a traffic forecast problem of postal parcel that arises at delivery stations of Korea Post. The main purpose of this paper is to describe a method for predicting short-term traffic of postal parcel based on self-similarity analysis and to introduce an application of the traffic prediction model to postal logistics system. The proposed scheme develops multiple regression models by the clusters resulted from feature engineering and individual models for delivery stations to reinforce prediction accuracy. The experiment with data supplied by main postal delivery stations shows the advantage in terms of prediction performance. Comparing with other technique, experimental results show that the proposed method improves the accuracy up to 45.8%.

Flower-like NiS/C as high-performance anode material for sodium-ion batteries

Transition metal sulfides are the promising anode materials for high-capacity sodium-ion batteries (SIBs). However, the pitfalls of poor conductivity and large volume expansion still restrict their applications. Herein, NiS/C with a uniform flower-like structure was successfully synthesized via a glucose-assisted hydrothermal method coupled with post-annealing strategy. The petal-shaped configuration shortens the diffusion path of sodium ions in electrochemical reaction. Significantly, the formed uniform amorphous carbon is more effective in improving the electrical conductivity of electrode materials and buffering for the rapid volume change. When regarded as the anode of SIBs, the NiS/C electrode delivers a high reversible specific capacity of 1042.3 mAh g−1 at 0.1 A g−1. The excellent electrochemical performance shows that the NiS/C offers great potential for the development and research of large-scale energy storage of metal sulfide electrodes in the future.

OrganoidTracker: Efficient cell tracking using machine learning and manual error correction.

Time-lapse microscopy is routinely used to follow cells within organoids, allowing direct study of division and differentiation patterns. There is an increasing interest in cell tracking in organoids, which makes it possible to study their growth and homeostasis at the single-cell level. As tracking these cells by hand is prohibitively time consuming, automation using a computer program is required. Unfortunately, organoids have a high cell density and fast cell movement, which makes automated cell tracking difficult. In this work, a semi-automated cell tracker has been developed. To detect the nuclei, we use a machine learning approach based on a convolutional neural network. To form cell trajectories, we link detections at different time points together using a min-cost flow solver. The tracker raises warnings for situations with likely errors. Rapid changes in nucleus volume and position are reported for manual review, as well as cases where nuclei divide, appear and disappear. When the warning system is adjusted such that virtually error-free lineage trees can be obtained, still less than 2% of all detected nuclei positions are marked for manual analysis. This provides an enormous speed boost over manual cell tracking, while still providing tracking data of the same quality as manual tracking.

Autogenous and drying shrinkage of mortars based on Portland and calcium sulfoaluminate cements

Calcium sulfoaluminate (CSA) cement can be used as an alternative binder in concrete, partially or fully replacing ordinary Portland cement. While CSA cement considerably accelerates the mechanical properties development, the rapid evolution of the microstructure together with the high water demand cause rapid and large volume changes at early ages. As volume changes may lead to early-age cracking, measures to reduce them may be required In this paper, autogenous and drying shrinkage are studied in mortars prepared with Portland cement, CSA cement or a 50/50 blend as binder. Very fast self-desiccation and high autogenous shrinkage of the CSA-based mortar were observed compared to the mortar made with Portland cement. On the other hand, the early-age volume changes can be limited if a blend of the two cements is used. The blended system revealed a bi-modal trend in the evolution of self-desiccation and autogenous shrinkage, in which the initial fast self-desiccation and shrinkage enter the dormant phase after the first couple of days and again start after about 28 days.

Climatic signals in lacustrine deposits of the Upper Yacoraite Formation, Western Argentina: Evidence from clay minerals, analcime, dolomite and fibrous calcite

AbstractAuthigenic clays are an important control on reservoir quality in lacustrine carbonates but remain challenging to predict. Lacustrine depositional systems respond to climatic variations in rainfall, surface runoff and groundwater input, and evaporation, and result in rapid and frequent changes in lake volume; this is expressed through changing water depth and shoreline position. In the upper portion of the Early Palaeocene Yacoraite Formation of the Salta Basin in Argentina, extensive lacustrine deposits were deposited during the sag phase of rifting. Prior high‐resolution stratigraphic studies have suggested that climatic factors control microbial carbonate sequences within a ‘balanced fill’ lake, with variation in the lake level having a major influence on facies association changes. This study characterizes the evolution of facies and mineralogy within the Yacoraite Formation, focusing on the distribution of clay minerals, making a link between the high, medium and low‐frequency sequence stratigraphic cycles. The low‐frequency transgressive hemicycle of the upper portion of the Yacoraite Formation is comprised of abundant siliciclastic facies, suggesting a wetter period. Microbialites occurring in this interval are coarse‐grained and agglutinated. Detrital clay minerals such as illite and chlorite and associated siliciclastic sediments were input to the lake during high‐frequency transgressive periods. During high‐frequency regressive hemicycles, sedimentation was dominated by carbonate facies with Ca‐rich dolomite and the authigenic clays are comprised of chlorite/smectite mixed‐layers. By contrast, the low frequency regressive hemicycle records fine‐grained agglutinated microbialite with horizons of fibrous calcite, more stoichiometric dolomite, barite and authigenic magnesian smectite. This indicates elevated ion concentrations in the lake under intense evaporation during an arid period. Understanding the conditions that are favourable for formation and preservation of authigenic clays within the lacustrine environment can improve understanding of reservoir quality in comparable economically important deposits.

Promoting electrochemical performances of vanadium carbide nanodots via N and P co-doped carbon nanosheets wrapping

Abstract High theoretical specific capacity, good electrical conductivity, intrinsically stable metallic nature, excellent thermal stability and corrosion resistance enable vanadium carbide (VC) as a promising anode material for sodium-ion and lithium-ion batteries (SIBs and LIBs). However, drastic structural change during cycling and poor electrochemical kinetic performance both make the application of VC in dilemma. Herein, VC nanodots were successfully embedded in N and P co-doped carbon nanosheets (NPC) via a simple wet chemical process followed by high-temperature calcination. Benefiting from the carbon based conductive network and supporting structure for the rapid ion transport and alleviative volume change in VC, the VC@NPC hybrid exhibits a high reversible capacity (250 mA h g−1 at 0.1 A g−1 after 200 cycles), superior rate capability (88 mA h g−1 at a current density of 5.0 A g−1), and excellent cycle performance (97% capacity retention for 600 cycles at 1.0 A g−1) when evaluated as an anode material for SIBs. Besides, as for LIBs, VC@NPC also shows a high capacity of 532.2 mAh g−1 after 200 cycles at 0.1 A g−1 and 216.6 mAh g−1 after 500 cycles at 1.0 A g−1. This study provides a unique nanocomposite system to achieve a superior electrochemical performance and may pave the way for the further design and construction of novel transition metal carbide anode materials for SIBs, LIBs and other areas.

Regional lung function in nonsmokers and asymptomatic current and former smokers.

Electrical impedance tomography (EIT) is able to detect rapid lung volume changes during breathing. The aim of our observational study was to characterise the heterogeneity of regional ventilation distribution in lung-healthy adults by EIT and to detect the possible impact of tobacco consumption.A total of 219 nonsmokers, asymptomatic ex-smokers and current smokers were examined during forced full expiration using EIT. Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC were determined in 836 EIT image pixels for the analysis of spatial and temporal ventilation distribution. Coefficients of variation (CVs) of these pixel values were calculated. Histograms and medians of FEV1/FVCEIT and times required to exhale 50%, 75%, 90% of FVCEIT (t50, t75 and t90) were generated.CV of FEV1/FVCEIT distinguished among all groups (mean±sd: nonsmokers 0.43±0.05, ex-smokers 0.52±0.09, smokers 0.62±0.16). Histograms of FEV1/FVCEIT differentiated between nonsmokers and the other groups (p<0.0001). Medians of t50, t75 and t90 showed the lowest values in nonsmokers. Median t90 separated all groups (median (interquartile range): nonsmokers 0.82 (0.67–1.15), ex-smokers 1.41 (1.03–2.21), smokers 1.91 (1.33–3.53)).EIT detects regional ventilation heterogeneity during forced expiration in healthy nonsmokers and its increase in asymptomatic former and current smokers. Therefore, EIT-derived reference values should only be collected from nonsmoking lung-healthy adults.

Role of Nox4 in Angiotensin II‐Mediated Changes in Volume Dynamics and Nitric Oxide Production in Podocytes

Nitric oxide (NO) is a powerful vasodilator that serves important functions in the kidney such as regulation of renal hemodynamics, pressure natriuresis, and diuresis. Significant reduction in NO production has been found to play a role in the pathogenesis of hypertension. Our recent studies revealed that Angiotensin II (Ang II), in addition to causing a release of calcium, stimulates NO production in the glomerular podocytes. This signaling pathway can be also triggered by extracellular application of hydrogen peroxide (H2O2) and is significantly reduced with the development of salt‐sensitive hypertension and kidney injury in Dahl salt‐sensitive (SS) rats (Palygin et al., Nitric Oxide, 2018). Recently, using a knock out of NADPH oxidase 4 (Nox4) in SS rats (SSNox4−/−), one of the primary source of renal reactive oxygen species (ROS) and specifically H2O2 we described the reduction in intracellular calcium activation in podocytes as well as H2O2 production in isolated glomeruli in response to Ang II (Ilatovskaya et al., J Am Soc Nephrol. 2018). Overall, SSNox4−/− rats displayed a protective phenotype with a significant reduction of albuminuria, glomeruli injury and reduction in the elevation of blood pressure under high salt challenge (Cowley et al., Hypertension, 2016). Here we used this model to characterize the effects of alterations in the balance in the relationship between ROS and NO production in podocytes and establish the relation between Nox4 and glomerular/podocyte volume dynamics. The in vivo concentration of H2O2, measured by biosensors amperometry as catalase sensitive current, was significantly reduced in both cortex and medullar parts of the SSNox4−/− rat kidney compared to wild type SS rats, indicating a direct association between Nox4 and the production of renal ROS. We found that acute application of Ang II promoted opposite changes in glomeruli and podocyte volumes, where glomeruli volume decreased, and podocyte volume increased approximately by 18% in SS rats. Overall, SSNox4−/− rats exhibited an increase in total NO production (by 16% to compare with SS), calculated using confocal microscopy as a total integral of NO fluorescent transient (DAF‐FM dye) in the population of podocytes within a freshly isolated glomerulus. In SSNox4−/− rats the elevation in NO together with declining in H2O2 levels directly correlated with an increase of podocyte volume in response to Ang II (13% vs. SS control). We anticipate a rapid podocyte volume change dependent on intracellular NO production and reflecting the ability of these cells to dynamically regulate the permeability of glomeruli filtration barrier. Thus far, we can conclude that in the absence of Nox4 the podocytes shift the ROS production in response to Ang II towards the increase of intracellular NO bioavailability and a decrease of renal H2O2 production. This mechanism may play a key role in the protection of glomeruli form oxidative stress and elevation of blood pressure during the development of salt‐sensitive hypertension.Support or Funding InformationNHLBI R35 HL135749; P01 HL116264; AHA 18PRE34030127; ADA 1‐15‐BS‐172; DK‐020595 Pilot &amp; Feasibility projectThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

GO@Polyaniline Nanorod Array Hierarchical Structure: A Photothermal Agent with High Photothermal Conversion Efficiency for Fast Near-Infrared Responsive Hydrogels

Near-infrared (NIR) responsive hydrogels are of significance in remote control microvalves. However, the development and the application of NIR responsive hydrogels were either limited by high cost or limited by long response time (on the order of minutes) and modest volume change. To address this problem, in this work, a graphene oxide@polyaniline (GO@PANI) hybrid nanocomposite with nanorod array hierarchical structure was fabricated by dilute polymerization. The as-synthesized hierarchical GO@PANI nanosheets exhibited high NIR photothermal conversion efficiency (PTCE) (49%), which was approximately 188% the magnitude of that of GO sheets. Due to its high photothermal conversion efficiency, when GO@PANI was incorporated into temperature-responsive poly(N-isopropylacrylamide) (PNIPA), a highly responsive hydrogel with rapid and significant NIR-induced volume change (over 50%) was obtained. When this material was applied as a remote-controllable microvalve, it exhibited a fast NIR response (∼30 s).

Impact of the Environment upon the Candida albicans Cell Wall and Resultant Effects upon Immune Surveillance.

The fungal cell wall is an essential organelle that maintains cellular morphology and protects the fungus from environmental insults. For fungal pathogens such as Candida albicans, it provides a degree of protection against attack by host immune defences. However, the cell wall also presents key epitopes that trigger host immunity and attractive targets for antifungal drugs. Rather than being a rigid shield, it has become clear that the fungal cell wall is an elastic organelle that permits rapid changes in cell volume and the transit of large liposomal particles such as extracellular vesicles. The fungal cell wall is also flexible in that it adapts to local environmental inputs, thereby enhancing the fitness of the fungus in these microenvironments. Recent evidence indicates that this cell wall adaptation affects host-fungus interactions by altering the exposure of major cell wall epitopes that are recognised by innate immune cells. Therefore, we discuss the impact of environmental adaptation upon fungal cell wall structure, and how this affects immune recognition, focussing on C. albicans and drawing parallels with other fungal pathogens.

(Invited) Angle-Independent Structurally Coloured Hydrogels

Stimuli-sensitive soft materials composed of three-dimensional polymer networks or block copolymers with fine periodic dielectric structures of dimensions comparable to the wavelength of visible light can display bright structural colours[ 1 - 5 ]. The hues of the structural colours can reversibly change by varying the periodic dielectric structures with different stimuli. Extensive research has been performed in recent decades to develop such stimuli-sensitive structurally coloured soft materials for application to displays[ 2 , 4 , 6 ] and sensor systems[ 5 , 7 ]. In contrast to any other display and sensor technologies, these stimuli-sensitive structurally coloured soft materials can exhibit a wide range of colours on their own, without requiring colour filters and complicated control devices[ 2 ]. However, the colours produced by the periodic dielectric structures show distinct variations depending on the viewing and light illumination angles[ 8 ]. The iridescence originates from the Bragg reflection, resulting from the long-range order of the periodic structures. For potential applications to reflective full-colour displays and sensor systems with wide viewing angles, the angular dependence of the structural colour is a major issue. In this study, we report the development of thermally tunable, angle-independent, structurally coloured hydrogels. We demonstrate that the application of colloidal amorphous arrays as templates and the introduction of a small amount of black particles into the thermo-sensitive hydrogels are effective for obtaining tunable and angle-independent bright coloured systems. Many examples of stimuli-sensitive structurally coloured soft materials with rapid response and hue changes have been reported; however, such systems without angle-independent structural colours have yet to be reported. The porous PNIPA hydrogels prepared using colloidal amorphous array templates can exhibit rapid changes in volume in response to temperature variations and can potentially display angle-independent structural colours. Our results showed that the microstructure of the prepared hydrogels using the colloidal amorphous arrays as templates is not suitable for displaying brightly saturated structural colours due to the large contribution from incoherent multiple scattering of light to the optical properties. The small amount of CB introduced into the porous hydrogels suppressed multiple scattering, enabling clearer observations of the structural colours. This method is easily applicable to many other existing stimuli-sensitive soft materials. We expect that such stimuli-sensitive soft materials displaying bright, angle-independent structural colours will have many useful applications, such as in (bio)chemical sensing technology and electronic paper. [1] a) Y. Takeoka, J Mater Chem C 2013, 1, 6059; b) Y. Takeoka, T. Seki, Langmuir 2006, 22, 10223. [2] A. C. Arsenault, D. P. Puzzo, I. Manners, G. A. Ozin, Nat. Photonics 2007, 1, 468. [3] a) Y. Kang, J. J. Walish, T. Gorishnyy, E. L. Thomas, Nat. Mater. 2007, 6, 957; b) Y. F. Yue, T. Kurokawa, M. A. Haque, T. Nakajima, T. Nonoyama, X. F. Li, I. Kajiwara, J. P. Gong, Nat. Commun. 2014, 5, 4659. [4] K. Matsubara, M. Watanabe, Y. Takeoka, Angew. Chem. Int. Edit. 2007, 46, 1688. [5] D. Nakayama, Y. Takeoka, M. Watanabe, K. Kataoka, Angew. Chem. Int. Edit. 2003, 42, 4197. [6] K. Ueno, K. Matsubara, M. Watanabe, Y. Takeoka, Adv. Mater. 2007, 19, 2807. [7] a) J. H. Holtz, S. A. Asher, Nature 1997, 389, 829; b) C. J. Zhang, M. D. Losego, P. V. Braun, Chem. Mater. 2013, 25, 3239. [8] Y. Takeoka, J. Mater. Chem. 2012, 22, 23299. Figure 1

Trefoil factor family peptides enhance cell migration by increasing cellular osmotic permeability and aquaporin 3 levels.

Trefoil factor family (TFF) peptides are produced rapidly at sites of injury, stimulating epithelial migration, a process involving rapid changes in cell shape and volume, requiring rapid flow of water into and out of the cell. We examined the effect of TFFs on fluidity of cells by measuring their sensitivity to osmotic challenges and cell migration, and determined whether those results were mediated through altering the levels of aquaporins (AQPs), a family of transmembrane water channels involved in cellular water homeostasis. Gastric (AGS) and colonic (Caco-2) cell lines had intrinsic TFF levels determined and the predominant TFF peptide knocked down (RNA interference). Knockdown caused lessened responsiveness to changes in external osmotic challenge (by 51 and 69% in AGS and Caco-2 cells, respectively) and reduced cell migration and transepithelial permeability but did not influence proliferation. Exogenous TFF increased several AQPs, particularly AQP3, and those were reciprocally reduced in knockdown cells. TFF-induced, but not fetal calf serum-induced, cell migration was inhibited by the presence of AQP3 blocker (CuSO4). We summarize that TFF peptides promptly produced at sites of injury increase AQP levels, most notably AQP3, thereby enhancing the cells' ability to rapidly change their shape as part of the restitutive process. TFF peptides also require functioning AQP3 channels to induce cell migration.-Marchbank, T., Playford, R. J. Trefoil factor family peptides enhance cell migration by increasing cellular osmotic permeability and aquaporin 3 levels.

Can hemodialysis change QRS axis in patients without cardiovascular disease?

Due to rapid changes in volume and electrolyte concentration during hemodialysis (HD), some electrocardiographic (ECG) changes or arrhythmias can be seen. The aim of this study was to assess ECG QRS axis changes and other ECG parameters after HD in patients with end-stage renal disease (ESRD). A total of 46 patients (65% male, mean age 52±15 years) with a sinus rhythm and without cardiovascular disease who were undergoing chronic HD treatment were included to the study. Blood samples, 12-lead electrocardiograms, and echocardiograms were recorded immediately before and at the end of an HD session. The QRS axis and other electrocardiographic, echocardiographic, electrolyte parameter, and volume changes were analyzed. The serum urea, creatinine, potassium, and B-type natriuretic peptide concentrations significantly decreased after HD, and the serum calcium levels significantly increased after HD. Body weight significantly decreased after HD. There was no significant difference in the QRS duration, PR interval, P-wave axis, QRS axis, or QT and QTc interval following HD. Based on a comparison of variables according to the any QRS axis change after HD treatment, there was no significant difference in biochemical values, HD time, ultrafiltration volume, left ventricular ejection fraction, or other echocardiographic findings. ESRD and HD are complex and dynamic processes, and the change in the QRS axis is rarely emphasized in these patients. In our study, there was no significant change in the QRS axis with HD in patients without cardiovascular disease.

Effect of Topography on Subglacial Discharge and Submarine Melting During Tidewater Glacier Retreat

To first order, subglacial discharge depends on climate, which determines precipitation fluxes and glacier mass balance, and the rate of glacier volume change. For tidewater glaciers, large and rapid changes in glacier volume can occur independent of climate change due to strong glacier dynamic feedbacks. Using an idealized tidewater glacier model, we show that these feedbacks produce secular variations in subglacial discharge that are influenced by subglacial topography. Retreat along retrograde bed slopes (into deep water) results in rapid surface lowering and coincident increases in subglacial discharge. Consequently, submarine melting of glacier termini, which depends on subglacial discharge and ocean thermal forcing, also increases during retreat into deep water. Both subglacial discharge and submarine melting subsequently decrease as glacier termini retreat out of deep water and approach new steady state equilibria. In our simulations, subglacial discharge reached peaks that were 6–17% higher than preretreat values, with the highest values occurring during retreat from narrow sills, and submarine melting increased by 14% for unstratified fjords and 51% for highly stratified fjords. Our results therefore indicate that submarine melting acts in concert with iceberg calving to cause tidewater glacier termini to be unstable on retrograde beds. The full impact of submarine melting on tidewater glacier stability remains uncertain, however, due to poor understanding of the coupling between submarine melting and iceberg calving.

An investigation of regional cerebral blood flow and tissue structure changes after acute administration of antipsychotics in healthy male volunteers.

Chronic administration of antipsychotic drugs has been linked to structural brain changes observed in patients with schizophrenia. Recent MRI studies have shown rapid changes in regional brain volume following just a single dose of these drugs. However, it is not clear if these changes represent real volume changes or are artefacts ("apparent" volume changes) due to drug-induced physiological changes, such as increased cerebral blood flow (CBF). To address this, we examined the effects of a single, clinical dose of three commonly prescribed antipsychotics on quantitative measures of T1 and regional blood flow of the healthy human brain. Males (n = 42) were randomly assigned to one of two parallel groups in a double-blind, placebo-controlled, randomized, three-period cross-over study design. One group received a single oral dose of either 0.5 or 2 mg of risperidone or placebo during each visit. The other received olanzapine (7.5 mg), haloperidol (3 mg), or placebo. MR measures of quantitative T1, CBF, and T1-weighted images were acquired at the estimated peak plasma concentration of the drug. All three drugs caused localized increases in striatal blood flow, although drug and region specific effects were also apparent. In contrast, all assessments of T1 and brain volume remained stable across sessions, even in those areas experiencing large changes in CBF. This illustrates that a single clinically relevant oral dose of an antipsychotic has no detectable acute effect on T1 in healthy volunteers. We further provide a methodology for applying quantitative imaging methods to assess the acute effects of other compounds on structural MRI metrics. Hum Brain Mapp 39:319-331, 2018. © 2017 Wiley Periodicals, Inc.