Ice Salinity Research Articles

Application of Low-Temperature Ice Saline Bone Cement in Percutaneous Vertebroplasty

Percutaneous vertebroplasty uses the traditional method of bone cement filler to inject bone cement, which is easy to solidify, we have found a new method to delay the solidification of bone cement: low temperature ice saline bone cement, which compares the advantages of the new method and the traditional method of injecting bone cement. 82 cases of osteoporotic vertebral compresion fracture(OVCF) were divided into two groups by retrospective study method, 40 patients in group A were treated with the traditional method, 42 patients in group B were treated with the new method.The leakage rate of bone cement, postoperative VAS score, amount of bone cement in each vertebral body, operation time of bone cement, and number of bone cement fillers used were compared between the two groups. There was no significant difference in the bone cement leakage rate, postoperative VAS score, the amount of bone cement in each vertebral body and the number of bone cement fillers used between the two groups; the operation time of bone cement in two groups was statistically significant, and the operation time in group B was significantly longer than that in group A. Low temperature ice saline water bone cement has significant advantages in multiple vertebral fractures, relatively large amount of bone cement injected into each vertebral body and long operation time, which is more suitable for beginners.

Study on freezing separation process through observing microstructure of NaCl solution ice

Freezing desalination is a method to purify saline water. Researchers believe that the salt inclusions distributed inside ice affect the sea ice salinity, but there is not sufficient visualized proof that has been obtained via direct and non-destructive experiments to support this view. Even less study has been carried out on the salt inclusion distribution inside ice below the eutectic temperature. In this paper, a NaCl solution ice sample was prepared with the original mass concentration of 3 wt% using unidirectional heat transfer method. The freezing temperature was −24 ℃, which is lower than −21.2 ℃, the eutectic temperature of NaCl solution. Micro-CT device was used to scan the upper, middle and lower parts of a 3 wt% NaCl solution ice sample and the 5-layer U-Net architecture in DL (deep learning) module of the Dragonfly program was used to segment images to extract the information of interest. The image characteristics of salt inclusions and air bubbles inside the ice were obtained. Very high salt inclusion area proportion was found in the surface layer images of the sample with the maximum area proportion of about 43%. Experiments were also carried out to measure the salinity distribution inside the same solution ice samples. It was found that in the surface and bottom ice layers, the salinity is higher than that of the original solution. In the experiments, for the layers cut from the top and bottom of the 3 wt% NaCl solution ice sample, each of them possesses 10% of the solution ice sample mass, their salinities were 4.28 wt% and 5.41 wt%, respectively. Comparing the measurement results with the micro-CT image processing results, it was found that the variation tendency of the area proportion of salt inclusions is consistent with that of the ice layer salinity. The combination of micro-CT technology with DL image processing method has been proved an effective way to visualize and analyze quantitatively the internal structure of salt solution ice. Then, three NaCl solution samples that have the original mass concentrations of 3 wt%, 6 wt% and 9 wt%, and a pure water sample were frozen under the same conditions. The middle parts of the four ice samples were scanned and the obtained micro-CT images were processed. It can be found that in the middle parts of the three NaCl solution ice samples, the area proportions of salt inclusions increase from top to bottom and are positively correlated with the original salinities of the solution ice. The factors affecting air bubble distribution are more complex than that affecting salt inclusion distribution.

Transpulmonary cardiac output with room temperature saline is accurate and tracks directional changes in anesthetized dogs.

To assess the performance of transpulmonary thermodilution (TPTD) using room-temperature saline (CORT) and waveform-derived continuous CO (CCO) compared with TPTD using iced saline (COICED) as the indicator for measurements of CO in isoflurane-anesthetized dogs. 8 Beagles aged 1 to 2 years (7.4 to 11.2 kg) were enrolled in this experimental study from March 21 to 31, 2023. Dogs were anesthetized with 0.01 mg/kg acepromazine, 5 to 6 mg/kg propofol, and isoflurane and were mechanically ventilated. Dogs were instrumented with a central venous catheter and a femoral arterial catheter equipped with a thermistor. The COICED, CORT, and pulse wave-derived CCO values were obtained at baseline, during infusions of phenylephrine and norepinephrine, and during blood withdrawal and replacement. Data were analyzed with a mixed effect model, Bland-Altman plots, and concordance. Percent error was calculated. P < .05 was used for significance. Data were collected from 8 dogs. Significant effects of time and the interaction of time and method were found. Bland-Altman plots showed negligible bias with limits of agreement between -0.35 and 0.25 L/min for CORT versus COICED and -1.23 and 1.15 L/min for CCO versus COICED. Percent errors were 17.7% and 66.6%, respectively. In the 4-quadrant plots, the concordance rate was 95% and 68% for measurements obtained with CORT and for CCO, respectively. Transpulmonary thermodilution using room temperature saline was accurate and able to track changes in CO. Continuous CO had a large percent error and low tracking ability. Transpulmonary thermodilution using room temperature saline is reliable for monitoring CO and obviates the need for iced preparations in clinical scenarios.

Deicing performance analysis of the solution regenerator unit using freeze concentration

During the process of regeneration, freeze concentration exhibits high energy efficiency. The performance of regeneration is directly affected by the separation effect and salinity level of ice under different regeneration conditions. In order to evaluate the energy efficiency of deicing under different conditions, a freeze concentration solution regenerator unit was constructed and equipped with a heat pump system. Based on experimental data, the theoretical model of average distribution coefficient and deicing energy consumption is established to study the influence of ice separation efficiency and solute residue on the deicing energy consumption. Results show the ice salinity reduces the effect of ice amount on regeneration concentration. The increase of icing difficulty and ice salinity are the two main reasons that affect the decrease of deicing operation efficiency of high concentration solution. As the amount of ice separating decreases, the deicing energy efficiency is more sensitivity to the solute residue. The reduction rate of energy consumption is equal to the proportion of influence of solute residue in deicing energy efficiency. From 6%, 8%, 10% and 13% concentration, solute residue increases the deicing energy efficiency by an average of 2.4%, 3.4%, 4.6%, and 6.6%, respectively. The influence of solute residue on deicing operation efficiency can be reduced by increasing separation efficiency. The deicing energy consumption diagram of anti-frost solution freeze concentration system is proposed. The investigations will be helpful to improving the energy efficiency and steadiness of the heat pump with freeze concentration.

Numerical simulation of dynamic layer freeze desalination within an indirect contact freeze crystallizer

In the current study, a dynamic layer freeze desalination system is simulated numerically. The computational domain is a two-dimensional rectangular channel which contains inlet and outlet flows, and the simulation is performed using computational fluid dynamics. A pre-concentrated mixture is considered as the feed solution with an initial temperature and concentration of 257 K and 0.2 kg/kg, respectively. In this work, since the simulation parameters such as temperature and species mass fraction have high importance across the entire domain, the k–ω shear stress transport turbulence model was selected. A parametric study on the effect of the heat flux of the cold wall on the ice salinity and desalination rate is performed using three cases with heat fluxes of −1000, −1500, and −3000 Wm−2. It is observed that the ice generation speed in the case with a heat flux of −3000 Wm−2 is 3.28 times greater compared to the case with −1000 Wm−2 and its desalination rate is only 2.59% lower. The effect of the inlet velocity on the mentioned parameters is also investigated. It is observed that the cases with turbulent flow have approximately 19% and 23% lower ice salinity compared to the case with laminar flow.

Retrieval of sea ice thickness from FY-3E data using Random Forest method

In this study, we employ a Random Forest approach to estimate sea ice thickness (SIT) using Fengyun-3E (FY-3E) and Soil Moisture Ocean Salinity (SMOS) data. This method relies on four input parameters: incidence angle (θ), reflectivity (Γ), sea ice salinity (S), and sea ice temperature (T). In addition, FY-3E can receive both Global Positioning System (GPS) and Beidou Navigation Satellite System (BDS) reflected signals. Evaluation for the Arctic region based on data spanning from October 2022 to April 2023 reveals that the proposed models trained on GPS and BDS signals from FY-3E achieve high consistency and low error. Take GPS signals as an example, coefficients of determination are 0.97 and 0.91 and mean absolute errors are 0.019 m and 0.032 m for the training and test sets, respectively. In general, SIT inversion based on GPS signals slightly exhibits a higher accuracy than that based on BDS signals, but both approaches display high performances. The areas with the highest accuracy of SIT estimation based on GPS and BDS signals are the Shelikhov Bay and the Okhotsk Sea, followed by the Bering Sea and the Bering Strait. We conclude that machine learning and data fusion are effective for SIT estimation.

Temperature and salinity in the Bohai Sea landfast ice: Observations and modelling

Temperature and salinity are essential thermodynamic properties of sea ice. A 40-day long field campaign was carried out in winter 2020/2021 in the northern Bohai Sea in the landfast sea ice to investigate the seasonal sea ice temperature and salinity evolution. Ice thickness was measured routinely. A thermistor string was used to measure the ice temperature. Ice samples were collected for salinity by coring (Sco) and crumbing (Scr) methods. The mean vertical values of Sco and Scr were 4.8–5.8 psu and 8.3–13.8 psu, respectively. In cold ice, Sco and Scr were very close to each other. When ice temperature increased to −5 °C, Sco and Scr tended to differ from each other, and the difference was at largest at ice bottom. The brine volume fraction (BVF) ranged between 0.03 and 0.21 for Sco and 0.03 and 0.32 for Scr. The growth of ice reached a maximum of 3.7 cm/day in very cold conditions, while the average growth rate was 0.8 cm/day comparable to other seasonally ice-covered seas. A numerical sea ice thermodynamic model was applied to simulate the ice thickness with particular attention to the effect of Sco and Scr on the ice mass balance. The modeled overall ice growth rate was 0.7 cm/day and agreed well with the observations but during cold periods the simulation was biased down (1.1 cm/day); a possible reason is underestimation of the thermal conductivity in the model. The modeled ice thickness differed by 3 cm when using Sco and Scr as the input salinity profiles indicating that salinity has a minor impact on sea ice mass balance during mid-winter.

Investigation of the Recent Ice Characteristics in the Bohai Sea in the Winters of 2005–2022 Using Multi-Source Data

The safety of winter activities in the Bohai Sea requires more detailed information on ice characteristics and a more refined ice zone division. In the present study, 1/12°-resolution sea ice characteristic data were obtained based on the NEMO-LIM2 ice–ocean coupling model that assimilated MODIS satellite sea ice observations from the years of 2005 to 2022 to acquire new sea ice hindcasting data. On this basis, the ice period, ice thickness, ice concentration, ice temperature, ice salinity, and design ice thickness for different return periods in the 1/4°-resolution refined zoning were analyzed, which were then compared with the sea ice characteristics in the previous 21-ice-zone standard. The distribution of ice temperature and ice salinity was closely related to the distribution of ice thickness. The results of ice period, ice thickness, and ice concentration, as well as design ice thickness for different return periods, and the comparison with the previous 21-ice-zone standards, showed that the ice condition on the west coast of the Bohai Sea has significantly reduced.

The Relationship Between Microwave Brightness Temperature, Salinity, and Thickness of Sea Ice Acquired With a Tank Experiment

The Relationship Between Microwave Brightness Temperature, Salinity, and Thickness of Sea Ice Acquired With a Tank Experiment

The relationship between the permeability and liquid water content of polycrystalline temperate ice

Abstract To better constrain meltwater transport and ice viscosity in temperate glaciers, particularly in ice stream shear margins, we use a custom permeameter to study the untested model relationship between the permeability of temperate ice and its liquid water content. The permeability of lab-made ice of two mean grain diameters (1.8 and 4.2 mm) is measured, and water content is controlled with the ice salinity and measured calorimetrically. Fluorescein dye is added to through-flowing, chilled water to highlight flow pathways through the ice after experiments. As predicted by a simple model, permeability increases with approximately the square of the water content and by about three orders of magnitude across water contents of 0.1–4.4%. However, permeability values are less than those of the model by average factors of 2.6 and 4.1 for the finer and coarser ice, respectively. This discrepancy is likely due to tortuous, truncated or air-clogged veins. The order-of-magnitude agreement between measured and modeled values may indicate that reduced permeability from these factors is nearly compensated by preferential flow in oversized veins that are isolated or arborescent. Both kinds of preferred flow pathways are observed but the latter only in fine-grained ice at water contents &gt; 2%.

Improvement of sea ice thermodynamics with variable sea ice salinity and melt pond parameterizations in an OGCM

Enhanced representation of sea ice processes in ocean modeling studies is required for advancing our understanding and prediction of the climate variability. In the present study, we improved the sea ice thermodynamics in an OGCM by introducing processes for variable sea ice salinity and melt ponds on sea ice. The former affects the latent heat and conductivity of sea ice as well as the salt budget in the ocean–sea ice system. We formulated salinification and desalination processes based on previous observational studies. Melt ponds enhance summertime surface melting by reducing the surface albedo. In our formulation of the melt pond thermodynamics, the shortwave radiation absorbed in the pond was partly released to the air and partly conducted to the underlying sea ice. By adopting these parameterizations, seasonal cycles of the sea ice salinity distributions in both hemispheres were generally reproduced. Simulated seasonal and interannual variations in the Arctic melt pond area and associated surface albedo reductions were basically consistent with observational estimates. The melt pond effect reduced the Arctic sea ice volume by about 1.5 × 103 km3 in the summer; half of this impact remained throughout the year. Our results suggest that the new parameterizations have the potential to improve the seasonal evolution of the sea ice thickness and concentration distributions, which would contribute to prediction studies.

Modeling of icing on a planar surface due to Sea spray and blowing Snow

Two main extensions of the time-dependent two-dimensional sea spray icing model ICEMOD2.1 (Horjen, 2015) is presented. The first extension, called ICEMOD2.2, is the inclusion of heat conduction through the accreted ice. This quantity has been calculated from the temperature distribution in the ice which varies with time. The second extension, called ICEMOD2.3, is the combined effect of sea spray and snow. No other icing models have ever before included this effect. The new models have been applied for some reported icing cases on the nearly vertical wall of the bulkhead of the large Norwegian coast guard vessel KV Nordkapp from 1983 to 1997. Local wind field above the boundary layer, heat loss by forced convection and wind stress have been approximated by using analytical formulas for the wind field around a single plate. The physics of instantaneous freezing of a fraction of supercooled droplets upon impact has been discussed and implemented in the model.The most severe icing conditions in Norwegian Arctic water often occur during polar lows, which are often followed up with heavy snow fall. Due to the inclusion of snow the thermal conductivity of the ice accretion is modified. Using an electrical analogy it is shown that this parameter decreases during snow conditions. Overall ice salinity and density are also affected by the snow.

Impact of satellite thickness data assimilation on bias reduction in Arctic sea ice concentration

The impact of assimilating satellite-retrieved Arctic sea ice thickness (SIT) on simulating sea ice concentration (SIC) climatology in CICE5 is examined using a data assimilation (DA) system based on the ensemble optimal interpolation. The DA of the SIT satellite data of CryoSat-2 and SMOS during 2011–2019 significantly reduces the climatological bias of SIC and SIT in both sea ice melting and growing seasons. Moreover, the response of SIC to SIT change is strongly dependent on the seasons and latitudinal locations. The SIT in the inner ice zone thickens due to the SIT DA during the boreal winter wherein the SIT observation is available; the ice melting throughout the subsequent seasons is attenuated to increase SIC during the boreal summer to reduce the simultaneous SIC bias. In marginal ice zones, the positive SIT bias depicted in the control simulation is significantly reduced by SIT DA, which reduces the positive SIC bias. The idealized experiments of reducing the SIT show that the enhanced ice bottom melting process plays a crucial role in reducing the SIC; the prescribed SIT thinning increases the ice bulk salinity due to the weak gravity drainage of brine and increases the ice bulk temperature due to the decrease of the sea ice albedo. The augmentation of the ice salinity and temperature contributes to the shrinkage of the ice enthalpy, boosting the bottom melting process, which leads to SIC decrease.

Microplastics in sea ice: A fingerprint of bubble flotation

Sea ice is heavily contaminated with microplastics (MPs), with the repeatedly confirmed increased number of larger-sized particles, deficit of fibers, and prevalence of materials denser than the surrounding water. To get insight into the drivers behind such a specific pattern, sets of laboratory experiments were performed on the formation of ice by cooling from the surface of fresh and salty (NaCl, 34 g/L) water, with particles of different sizes from heavy plastics (HPP) distributed initially over the bottom of the experimental volume. After freezing, about 50–60 % of HPP were trapped in ice in all the runs. Vertical distribution of HPP, plastic mass distribution, ice salinity (in saltwater experiments), and bubble concentration (in freshwater experiments) were recorded. Formation of bubbles on hydrophobic surfaces was the main cause of the entrapment of HPP into ice, with convection playing a secondary role. Supplementary bubble formation experiments with the same particles in water demonstrated that at larger fragments and fibers, several bubbles grow at the same time, so particle rising and residing at the surface is stable. Smaller HPP experience rising/sinking cycles with minimum time spent at the surface: one bubble is enough to cause a particle rising, but it is most often lost when colliding with the water surface. Application of the results to oceanic conditions is discussed. Oversaturation with gases due to various physical/biological/chemical processes and liberation of bubbles from methane seeps and melting permafrost are common in Arctic waters. Convective water motions are able to relocate HPP in vertical. Based on applied research, the bubble nucleation and growth, the hydrophobicity of weathered surfaces, the effectiveness of flotation methods for plastic particles are discussed. Interaction of plastic particles with bubbles is an important feature, still completely overlooked in the context of MPs behavior in marine environment.

A new continuous noninvasive finger cuff device (Vitalstream) for cardiac output that communicates wirelessly via bluetooth or Wi-Fi

BackgroundThe new noninvasive Vitalstream (VS) continuous physiological monitor (Caretaker Medical LLC, Charlottesville, Virginia), allows continuous cardiac output by a low pump-inflated, finger cuff that pneumatically couples arterial pulsations via a pressure line to a pressure sensor for detection and analysis. Physiological data are communicated wirelessly to a tablet-based user interface via Bluetooth or Wi-Fi. We evaluated its performance against thermodilution cardiac output in patients undergoing cardiac surgery.MethodsWe compared the agreement between thermodilution cardiac output to that obtained by the continuous noninvasive system during cardiac surgery pre and post-cardiac bypass. Thermodilution cardiac output was performed routinely when clinically indicated by an iced saline cold injectate system. All comparisons between VS and TD/CCO data were post-processed. In order to match the VS CO readings to the averaged discrete TD bolus data, the averaged CO readings of the ten seconds of VS CO data points prior to a sequence of TD bolus injections was matched. Time alignment was based on the medical record time and the VS time-stamped data points. The accuracy against reference TD measurements was assessed via Bland–Altman analysis of the CO values and standard concordance analysis of the ΔCO values (with a 15% exclusion zone).ResultsAnalysis of the data compared the accuracy of the matched measurement pairs of VS and TD/CCO VS absolute CO values with and without initial calibration to the discrete TD CO values, as well as the trending ability, i.e., ΔCO values of the VS physiological monitor compared to those of the reference. The results were comparable with other non-invasive as well as invasive technologies and Bland-Altman analyses showed high agreement between devices in a diverse patient population. The results are significant regarding the goal of expanding access to effective, wireless and readily implemented fluid management monitoring tools to hospital sections previously not covered because of the limitations of traditional technologies.ConclusionThis study demonstrated that the agreement between the VS CO and TD CO was clinically acceptable with a percent error (PE) of 34.5 to 38% with and without external calibration. The threshold for an acceptable agreement between the VS and TD was considered to be below 40% which is below the threshold recommended by others.

Estimates of certain physical and mechanical characteristics of ice in the Ob’ Bay

The ice cover of the Gulf of Ob is formed in an extended zone, where the sea and fresh waters are mixed. This study aims to evaluate certain physical and mechanical characteristics of such ice. It examines data on a complex of physical and mechanical fast ice characteristics in the Ob’ Bay, obtained in the course of field studies over the last 30 years. The total amount of data available to the team of authors exceeds 200 cores, sampled in the Ob’ Bay (from Novy Port to the boundary between the Bay and the Kara Sea) in different years and in different months of the ice season.Processed data on ice temperature are presented, as well as information on the evolution of integral ice temperature during ice season. The change of integral ice salinity in the Ob’ Bay with geographic latitude is identified and shown, and the function approximating this change is given.The estimates of average density and porosity of ice by thickness are presented. The effect of mineral inclusions on the increase in ice density is considered.An analysis was carried out of the correspondence between the field data on fresh and saline ice sample strength in uniaxial compression (with the load application parallel to the ice cover surface) with theoretical strength estimates from Russian and foreign scientific and methodological literature, based on the data obtained on physical and mechanical ice characteristics in the Ob’ Bay. A generalized estimate of the saline ice strength limit in the Ob’ Bay, obtained in uniaxial compression parallel to the surface of ice accumulation is given, as well as its approximation by lognormal distribution.The results obtained in the analysis of the strength characteristics of ice in the Gulf of Ob can be used for practical purposes. The results may also prove useful in terms of contribution to theoretical knowledge on the experimental mechanics of ice in desalinated water bodies.

Reclamation effects of distinct volumes and concentrations of CaCl2-amended brackish ice in different saline-sodic soils

The proper usage of marginal soil and water resources has major implications for the sustainability of agriculture, such as brackish water and saline-sodic soils. The saline soils can be ameliorated though melting process of calcium-containing brackish ice, however, the optimum concentration and volume of brackish ice (water) for the reclamation of different saline-sodic soils remain to be determined. In this study, 108 soil columns representing four Ice salinity levels (16, 26, 36, 46 mmolc L−1) and three Pore Volumes (2/3, 1.5, 2.5 PV) of calcium-amended brackish ice were tested to reveal the reclaiming effect on a range of saline-sodic soils. The linear mixed model (LMM), multiple regression equation, and principal coordinate analysis (PCoA) were applied to calculate the amelioration effect in terms of three factors: Ice volume, Ice salinity and Column depth. Our results showed that the soil salinity and sodicity generally decreased with increasing Ice volume and Ice salinity, and the saline-sodic soils with low exchangeable sodium percentages (i.e. ESP 20) were more sensitive to Ice salinity, with high salinity (26–46 mmolc L−1) and large volume (2.5 PV) of brackish ice reaching a better amelioration effect. The effect of Ice volume became more dominant in medium and high ESP soils (ESP 40 and ESP 70), whereas the high salinity combined with low volume of brackish ice would lead to worse soil properties, especially at the bottom layers. Meanwhile, the Column depth factor had a considerable effect on the soil chemical properties, with the variance explained ranging from 18.6% to 36.0%. These results provide theoretical guidance in the rational use of calcium-amended brackish ice and highlight the necessity to take layer effect into consideration for reclaiming saline-sodic soils.

Optimized sea ice simulation in MITgcm-ECCO2 forced by ERA5

Coupled ice–ocean models require an accurate performance of sea ice dynamics and thermodynamics to realistically simulate sea ice circulation in the polar regions. However, atmospheric surface variables from reanalysis products that force the models differ in spatial and temporal resolutions, and there are also substantial inconsistencies in the distributions and magnitudes of these variables between the products. Therefore, several key parameters in the models need to be adjusted for the models forced by different atmospheric reanalysis products. This study compares the sea ice properties simulated by the previously optimized MITgcm-ECCO2 model forced by JRA25 and forced by the recently released ERA5. The comparisons with high-resolution satellite sea ice data reveal that the simulations forced by these two datasets significantly overestimate the Arctic sea ice concentration in summer, whereas the simulation forced by ERA5 underestimates the winter Antarctic sea ice. It is likely that the downward longwave radiation and wind stress regime in ERA5 is responsible for the underestimated Antarctic sea ice cover. We then optimize MITgcm-ECCO2 model forced by ERA5 by using Green functions. We consider six key parameters: sea ice strength, ice-atmospheric drag coefficient, ice–ocean drag coefficient, ice and snow albedos, and sea ice salinity. The optimized simulation significantly improves the sea ice distribution in both regions using a more realistic set of sea ice parameters. The most significant improvement is in the Antarctic, where winter sea ice extent misfit decreases by 48%. The optimized simulation reveals that ERA5 reproduces a closer representation of the Arctic sea ice extent and thickness than JRA25. In the southern hemisphere, ERA5 simulates the sea ice drift better, whereas the JRA25 have the closest match to the sea ice extent. Despite the improvements, further work is necessary for the Antarctic, where the lack of reliable observational data and limitations of the ocean model hinders the optimization.

Tracking changes in the fjord environment over a winter season using ice bulk salinity and δ18O

Ice that forms in the fjords of northern Norway often undergoes temperature fluctuations, rising above and below freezing, throughout winter and experiences variable conditions at the ice-ocean interface due to changes in freshwater runoff from surrounding land. Conditions at the interface can be difficult to track throughout the season without consistent measurement, resultantly limiting understanding of how freshwater runoff from land may impact a fjord throughout winter. Ice samples gathered from fjords, however, offer a unique opportunity to examine the connection between bulk ice properties like salinity and δ18O and environmental conditions including growth rate and the composition of water at the interface. Using relationships from the literature, a method was developed to invert bulk ice salinity and δ18O simultaneously to determine the history of growth rate and interface water composition of ice samples gathered in March 2018 from six fjords located in northern Norway. Quantitative results depend on knowledge of salinity and δ18O of both the seawater and freshwater leading into the fjord. It was found that five of the six investigated sites had ice grown from a brackish layer with 0 to 40% seawater content, while one site had ice grown from water with 50 to 90% seawater content. The brine volume fraction of the ice from four out of the six fjords was partly or entirely below 5% which is too low to allow for efficient brine transport. It is additionally shown that at ice temperatures between −2 and 0 °C, ice grown from water having a composition of up to 30% seawater at the ice ocean interface will fall below the 5% brine volume fraction, depending on growth rate. Through use of this method, an improved understanding was obtained of fluctuations in the composition of water at the ice-ocean interface in a sub-arctic coastal environment and, when ice growth rate is considered, the substantial influence on ice bulk properties.

Echocardiographic imaging of a bifurcated double barrel coronary sinus

BackgroundThe coronary sinus (CS) is the terminal collecting vessel of the myocardial venous network, which returns deoxygenated blood used by the heart to the right atrium. The advent of high-fidelity imaging via CT and transesophageal echocardiography (TEE) has further defined the anatomy of the CS and its multiple tributaries. Understanding this anatomy is crucial for cardiac surgical cases that require the cannulation of the coronary sinus to deliver retrograde cardioplegia. However, anatomical variants of the CS may frustrate surgical retrograde catheter placement, in turn increasing the risk of CS injury or leading to inadequate cardioplegia delivery. Here, we present an especially unique CS presentation, a bifurcated, double-barrel CS, which was discovered via intraoperative TEE imaging that revealed a CS with two smaller lumens instead of the singular large os.Case presentationA 67-year-old male presented for ascending aortic dissection repair, aortic valve replacement, and single vessel coronary artery bypass graft. On the pre-bypass TEE exam, the anesthesiologist noted a bifurcated CS with two small lumens. The surgeon utilized this information to select a smaller diameter retrograde catheter to avoid damage or perforation of the vessel. With TEE guidance, the surgeon successfully cannulated one of the CS lumens. However, it was noted upon dosing of retrograde cardioplegia that all tributary vessels attached to the non-cannulated lumen remained devoid of cardioplegia. The surgeon was forced to repeatedly administer anterograde cardioplegia via a handheld catheter through the coronary ostium throughout the case. The operative field was also flooded with topical ice saline slush to ensure cardiac protection. Ultimately, the operation was completed without incident despite the non-ideal conditions resulting from this anatomic variant.ConclusionsDiscovery of this patient’s double-barrel CS during the pre-bypass TEE was incidental, showing that such anatomical variants may be completely asymptomatic and benign in the non-operative setting. However, the delivery of cardioplegia proved challenging for this patient, highlighting some degree of risk with certain cardiac interventions. This case demonstrates the utility of intraoperative TEE to quickly ascertain unforeseen anatomical variants of the CS which could compromise the safety of cardiac surgery cases.