Extra Volume Research Articles

Modeling the extra column volume of a micro simulated moving bed chromatography system: Introducing the equivalent radial flow rate distribution

Recently, the focus in chromatography model development has expanded to include the modeling of extra column volume (ECV), particularly in small- and lab-scale systems where ECV can constitute a significant portion of the total volume. Typically, ECV is modeled with 1D approaches, for example with combinations of dispersed plug flow reactors (DPFRs) and continuously stirred tank reactors (CSTRs). However, radial inhomogeneities in the ECV concentration profile necessitate higher-dimensional models for more accurate predictions. Searching for a suitable modeling approach for a micro simulated moving bed chromatography (μSMB) system, we investigated whether the 2D laminar flow model can be extended to account for additional dispersion effects, such as Dean vortices, through an equivalent radial flow rate distribution (eqFRD). For this purpose, we conducted 3D CFD simulations of the respective ECV and adapted the radial flow rate profile of a 2D simulation to match the residence time distribution observed in the CFD results. Applying the eqFRD model led to a significant improvement in prediction accuracy for isolated ECV segments, increasing from 90% to 97% compared to traditional ECV models. However, when these models were applied to the full μSMB system, the choice of ECV model had minimal impact on overall results as long as retention time within the ECV was accurately predicted. This suggests that, in the studied system, the column has a greater influence on peak shape than the ECV, allowing simpler ECV models to suffice in certain contexts. Despite these advances, significant deviations between predicted and experimental results were observed, indicating that factors such as the transition between the column and ECV, as well as detector effects, should be considered in future research. The results underscore the importance of selecting an ECV model in the context of the entire system, balancing accuracy with computational efficiency.

An ecosystem of interconnected technologies to increase efficiencies in blood establishments: The example of the Blood and Tissue Bank of Aragón, Spain.

Blood establishments face environmental, financial, demographic and societal challenges that may impair sustainable blood supply to patients. This study presents the technologies (devices and software) assembled in a global ecosystem implemented by the Blood and Tissue Bank of Aragón (BTBA), Spain, over the last decade to overcome these challenges. Descriptive yearly activity data (2013-2023) of BTBA were retrospectively collected to evaluate the impact of different technologies on blood processing efficiency, focusing on the production of blood components (red blood cell concentrates [RCCs], platelet concentrates [PCs]) and plasma. Operator satisfaction about the technologies introduced in daily routine work was also monitored. Between 2013 and 2023, the annual production decreased by 16.0% for RCCs and increased by 13.3% for PCs. From 2020, all PCs were treated with pathogen reduction technology, and no inventory stock-out was reported. The lowest PC expiry rate (0.2%) was observed after the implementation of the software for blood processing and PC stock management. The deployment of this software also improved plasma recovery: on average, an extra plasma volume of 9 mL was collected per donation in 2023 compared to 2015. A survey confirmed staff satisfaction. The progressive implementation of automated and software-based solutions was key to increasing efficiencies in BTBA. This enabled the optimization of blood processing by maximizing productivity, enhancing traceability, reducing overproduction and wastage and increasing the yield of recovered plasma, while ensuring blood product safety and staff satisfaction.

Mass spectrometry coupling of chip-based supercritical fluid chromatography enabled by make-up flow-assisted backpressure regulation

This work introduces a novel microfluidic backpressure pressure control developed for chip-based supercritical fluid chromatography (chipSFC). The presented on-chip pressure control mechanism involves the post-column addition of a viscous make-up stream, which enables pressure regulation within the range of 73 to 130 bar range. In contrast to approaches using mechanical backpressure regulators, this chip-based make-up-assisted pressure regulation offers a wear-free alternative that functions entirely through fluidic means and contributes minimally to extra column volume. It prevents phase separation of the supercritical mobile phase and, therefore, expands the analytical scope of chipSFC to detection systems with an ambient pressure interface. This was demonstrated by a proof-of-principle experiment, where a model mixture was separated within 30 s and detected using atmospheric pressure ionisation mass spectrometry.Graphical abstract

Pediatric diffuse intrinsic pontine glioma radiotherapy response prediction: MRI morphology and T2 intensity-based quantitative analyses

ObjectivesAn easy-to-implement MRI model for predicting partial response (PR) postradiotherapy for diffuse intrinsic pontine glioma (DIPG) is lacking. Utilizing quantitative T2 signal intensity and introducing a visual evaluation method based on T2 signal intensity heterogeneity, and compared MRI radiomic models for predicting radiotherapy response in pediatric patients with DIPG.MethodsWe retrospectively included patients with brainstem gliomas aged ≤ 18 years admitted between July 2011 and March 2023. Applying Response Assessment in Pediatric Neuro-Oncology criteria, we categorized patients into PR and non-PR groups. For qualitative analysis, tumor heterogeneity vision was classified into four grades based on T2-weighted images. Quantitative analysis included the relative T2 signal intensity ratio (rT2SR), extra pons volume ratio, and tumor ring-enhancement volume. Radiomic features were extracted from T2-weighted and T1-enhanced images of volumes of interest. Univariate analysis was used to identify independent variables related to PR. Multivariate logistic regression was performed using significant variables (p < 0.05) from univariate analysis.ResultsOf 140 patients (training n = 109, and test n = 31), 64 (45.7%) achieved PR. The AUC of the predictive model with extrapontine volume ratio, rT2SRmax–min (rT2SRdif), and grade was 0.89. The AUCs of the T2-weighted and T1WI-enhanced models with radiomic signatures were 0.84 and 0.81, respectively. For the 31 DIPG test sets, the AUCs were 0.91, 0.83, and 0.81, for the models incorporating the quantitative features, radiomic model (T2-weighted images, and T1W1-enhanced images), respectively.ConclusionCombining T2-weighted quantification with qualitative and extrapontine volume ratios reliably predicted pediatric DIPG radiotherapy response.Clinical relevance statementCombining T2-weighted quantification with qualitative and extrapontine volume ratios can accurately predict diffuse intrinsic pontine glioma (DIPG) radiotherapy response, which may facilitate personalized treatment and prognostic assessment for patients with DIPG.Key PointsEarly identification is crucial for radiotherapy response and risk stratification in diffuse intrinsic pontine glioma.The model using tumor heterogeneity and quantitative T2 signal metrics achieved an AUC of 0.91.Using a combination of parameters can effectively predict radiotherapy response in this population.

High-Coupled Magnetic-Levitation Hybrid Nanogenerator with Frequency Multiplication Effect for Wireless Water Level Alarm.

Hybrid nanogenerators (HNGs) represent a promising avenue for water energy harvesting, yet their commercial viability faces hurdles such as limited power output, poor coupling, and constrained operational lifespans. Here, a highly coupled triboelectric-electromagnetic magnetic-levitation hybrid nanogenerator (ML-HNG) is introduced that shows great potential for water energy harvesting. The ML-HNG fulfills the challenges of high power output, strong coupling, and long operational lifespans. During the contact-separation process of the triboelectric nanogenerator (TENG), the changing magnetic flux in the electromagnetic generator's coils generates a potential difference between the coils and Cu electrodes. The unique design of the ML-HNG employs a shared coil electrode configuration, which enhances the coupling without adding extra volume. This integration allows the ML-HNG to achieve multi-frequency vibrations and multiple output cycles per external longitudinal movement, a phenomenon known as the frequency multiplication effect. With an average power density of 1.69W m-3 in water, the ML-HNG provides continuous power for a thermo-hygrometer and can quickly drive a wireless water level alarm system within a minute. This groundbreaking hybrid nanogenerator design holds significant promise for the efficient and consistent harvesting of low-frequency ocean wave energy, marking a substantial advancement in blue energy technology.

Optimization of the Thermally Conductive Low-k Polymer Dielectrics Based on Multisource Free-Volume Effects.

Polymers/polymer matrix composites possessing low dielectric constants (low-k polymer dielectrics) contribute to the advance of electronics, for instance, microprocessor chips, mobile phone antennas, and data communication terminals. However, the intrinsic long-chain structural characteristic results in poor thermal conductivities, which draw heat accumulation and undermine the outstanding low-k performance of polymers. Herein, multisource free-volume effects that combine two novel kinds of extra free volume with the known in-cage free volume of polyhedral oligomeric silsesquioxanes (POSSs) are discussed to reduce the capacity for dielectric constant reduction. The multisource free-volume effects of POSSs are associated with the thermal conductive network formed by the hexagonal boron nitride (BN) in the polymer matrix. The results show a decent balance between low-k performance (dielectric constant is 2.08 at 1 MHz and 1.98 at 10 GHz) and thermal conductivity (0.555 W m-1 K-1, 4.91 times the matrix). The results provide a new idea to maximize the free-volume effects of POSSs to optimize dielectric properties together with other desired performances for the dielectrics.

BART: A transferable liquid chromatography retention time library for bile acids

Identification of unknown bile acids, especially the distinguishment between isomers, requires retention times of a large number of reference standards, which are often not commercially available. Meanwhile, published retention information cannot be directly transferred across labs due to the differences between liquid chromatography (LC) systems, such as different extra column volume and dwell volume. To improve this situation, a transferrable retention time library for bile acids named BART was developed. BART was composed of isocratic retention models of 272 bile acids and a software tool to predict their gradient retention times on various LC systems. The isocratic retention times of bile acids were acquired on a Waters BEH C18 column with mobile phases of acidic ammonium acetate buffer and acetonitrile, and fit to the quadratic solvent strength model (QSSM). Segmented linear gradient retention times were calculated with holdup time (t0), dwell time (tD) and actual gradient profile corrected using 21 bile acid calibration standards. In addition to the reference system where the isocratic retention times were acquired, this approach has been validated on four other LC-MS systems in four labs with two gradient methods. Average root mean square errors (RMSE) between predicted and experimental retention times were 0.052 and 0.054 min for the two gradients tested, which were 9-fold more accurate than referring to a static retention time library. The library is freely available at https://bafinder.github.io/.

Geometric Modification of Piano Key Weirs to Enhance Hydraulic Performance and Discharge Capacity

The piano key (PK) weir is a cost-effective structure for flood discharge. Its typical layout comprises a rectangularly cranked crest in planform with up- and downstream overhangs. With the intention to enhance its hydraulic efficiency, the conventional weir is improved. The sloping floor of each key is modified with a downward semi-circle in the cross-section; each overhanging apex is thus assigned an elliptical crest. Thus, the developed crest length of the resulting weir becomes considerably extended. Experiments are performed to compare the hydraulic behaviors of the improved weir with a reference one. The models are 3D-printed to attain high manufacture precision. For the model dimensions chosen in the study, the developed crest is ~36% longer. The study demonstrates that the improvements in geometry lead to appreciably enhanced flow discharge capacity. Within the hydraulic range examined, the augment in flow discharge varies within a range from 30% to 53%. In terms of both discharge capacity and flow patterns, the improved weir clearly outperforms the conventional one. The elliptical overhang apexes noticeably extend the developed crest length. The streamlined upstream overhang without singularity and the lowered inlet key floor reduce the entrance energy loss and improve the inflow to the inlet key and the flow over the crest. The lowered floor also gives rise to extra water volume, which administers to the flow motion towards the crest. For the outlet key, its lowered floor facilitates the outflow and alleviates the liableness of local submergence at high discharges. If the footprint for spillway construction is limited or the increase in the reservoir water stage must be controlled, the use of a more effective PK weir for flood discharge has significant engineering implications.

Effects of N2 O elimination on the elimination of second gases in a two-step mathematical model of heterogeneous gas exchange.

We have investigated the elimination of inert gases in the lung during the elimination of nitrous oxide (N2 O) using a two-step mathematical model that allows the contribution from net gas volume expansion, which occurs in Step 2, to be separated from other factors. When a second inert gas is used in addition to N2 O, the effect on that gas appears as an extra volume of the gas eliminated in association with the dilution produced by N2 O washout in Step 2. We first considered the effect of elimination in a single gas-exchanging unit under steady-state conditions and then extended our analysis to a lung having a log-normal distribution of ventilation and perfusion. A further increase in inert gas elimination was demonstrated with gases of low solubility in the presence of the increased ventilation-perfusion mismatch that is known to occur during anesthesia. These effects are transient because N2 O elimination depletes the input of that gas from mixed venous blood to the lung, thereby rapidly reducing the magnitude of the diluting action.

Innovative margin design and optimized isocenter to minimize the normal tissue in target volumes for single-isocenter multi-target stereotactic radiosurgery

Objective. Treating multiple brain metastases in a single plan is a popular radiosurgery technique. However, targets positioned off-isocenter are subject to rotational uncertainties. This work introduces two new planning target volumes (PTVs) that address this increased uncertainty. The volume of normal tissue included in these PTVs when paired with optimized isocenters are evaluated and compared with conventional methods. Approach. Sets of 1000 random multi-target radiosurgery patients were simulated, each patient with a random number of spherical targets (2–10). Each target had a random volume (0.1–15 cc) and was randomly positioned between 5 and 50 mm or 100 mm from isocenter. Two new PTVs (‘LensPTV’ and ‘SwipePTV’) and conventional isotropic PTVs were created using isocenters derived from the center-of-centroids, the center-of-mass, or optimized per PTV type. The total volume of normal tissue in the PTVs for each patient was calculated and compared using 1 mm translations and 0.5°, 1.0°, and 2.0° rotations. Main results. Using the new PTVs and/or using optimized isocenters decreased the total volume of normal tissue in the PTVs per patient. The SwipePTV, in particular, provided the greatest decrease. Compared to the SwipePTV, the LensPTV and the conventional isotropic PTV included an extra 0.68 and 0.73 cc of normal tissue per patient (median), respectively, when using 50 mm max distance to isocenter and 1° max rotation angle. Under these conditions, 25% of patients had extra volume of normal tissue ≥ 0.96 and 1.04 cc. When using 100 mm max distance to isocenter and 2° max rotation angle, 25% of patients had extra volume of normal tissue ≥ 4.35 and 5.75 cc. Significance. PTVs like those presented here, especially when paired with optimized isocenters, can decrease the total volume of included normal tissue and reduce the risk of toxicity without compromising target coverage.

Sliding behaviour of carbon nanothread within a bundle embedded in polymer matrix

Interfacial shear strength determines the load transfer efficiency between nanofillers and polymer matrix, and thus the overall mechanical performance of polymer nanocomposites. Through atomistic simulations, this work systematically assessed the sliding behaviours of one-dimensional carbon nanothread (NTH) from a bundle configuration embedded in the poly (methyl methacrylate) (PMMA) matrix. It is found that the functionalized NTH exhibits remarkably enhanced interfacial shear strengths due to the strong mechanical interlocking effect, about an order of magnitude higher than the pristine sample. However, excess volume is generated within a functionalized bundle structure, leading to a weaker non-bonded interaction for a functionalized NTH within the bundle than that only embedded in the polymer matrix. With covalent cross-linking, the surrounding NTHs can be simultaneously dragged out from the PMMA matrix while pulling out the central NTH. Such phenomenon attributes to the filler-filler interactions and filler-matrix interactions. Further studies reveal that no extra free volume is generated within the bundle structure at high temperatures, which retains the effective load transfer efficiency. In comparison, free volume tends to be generated at the interface between NTHs and PMMA matrix at a higher temperature. These findings could be beneficial for fibre design and high-performance polymer nanocomposites with 1D nanomaterials.

Fuzzy Control Algorithm Applied on Constant Airflow Controlling of Fans

Keeping a certain constant airflow in a lot of applications is critical, such as certain airflow volumes in the cabin of an aircraft, submarines, tunnels, and buildings. All fans change their output airflow and air pressure by changing motor speed in real applications. In order to achieve the target airflow volume, normal operation detects the data first, then provides orders to engineers to adjust manually. Extra airflow volume sensors are equipped to measure the airflow so that people know what the current airflow is and how much needs to be adjusted. Based on normal technology, airflow volume sensors and motor speed inverters are necessary parts of a whole air supply system. This research tries to integrate a fuzzy control algorithm into a motor control technology to build a new kind of fan that can not only self-detect the airflow volume changes but also can self-adjust the airflow volumes automatically. This self-detecting and adjusting fan can lead air supply systems in devices and buildings to need no airflow volume sensors, make the air supply system building cost lower, and make the maintaining and operating cost lower.

What makes athletes with extra training volume at a sports cardiology center different

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Athletes have always recognized the importance of training, but in modern times there has been a dramatic increase in the volume and intensity of training that athletes undergo. This has led to concerns about the potential risks associated with such high levels of training. However, there is also evidence to suggest that athletes who train the hardest may actually be at lower risk of developing cardiovascular problems. Objective To determine the proportion of athletes with arrhythmias screened at a sports cardiology center. To define the differences in care between an athlete with and without an arrhythmia. Methodology Retrospective analysis of the registry of all athletes of the one Sports Cardiology Centre. Statistical comparison of the cohort of athletes with weekly training volume above the 95th percentile versus the rest of the cohort. File: Between 1/2020-6/2022, a total of 115 cases of athletes, 100 males and 15 females (13%), aged 26 (+/-11 years) were examined and definitively closed at CSK. Median 95th percentile group training volume was 18 hours, mean 22 (+/3) hours vs 9 (+/- 3) hours (p&amp;lt;0.001), detailed in Table 1. Results The cohort of athletes in the greater than 95th percentile of weekly training volume sides differed statistically significantly from the rest of the cohort only in the type of sport according to ESC (typically endurance athletes, p=0.021) and the percentage of medication used regularly (50% vs 16.9%, p=0.039). Data summarized in Table 2. Conclusion Apart from the statistically significant greater use of regular medication, there was no difference from the rest of the cohort in workflow and sports cardiology centre outcomes in the cohort of those athletes with the highest training volume. The difference in heart dimensions and volumes on echocardiographic and MRI scans will be the subject of further investigation.

PERIAPICAL SURGERY WITH TRANSSURGICAL FILLING OF A TOOTH WITH EXTENSIVE PERIAPICAL LESION: CASE REPORT

This paper aims to describe a case of endodontic treatment associated with surgical treatment with apical curettage, apicectomy and transsurgical filling of a right upper lateral incisor with extensive periapical lesion. The patient attended the dental office reporting pain, facial swelling and fever. On clinical examination, an increase in extra and intra-oral volume was observed, affecting the bottom of the right upper sulcus; there was a negative response to the sensitivity test on tooth 12. The periapical radiograph showed the presence of an extensive periapical lesion involving the apices of teeth 11 and 12. In light of these findings, conventional endodontic treatment was chosen. The chemical-mechanical preparation was performed with X1-Blue mechanized files associated with 2.5% sodium hypochlorite and, after three changes of intracanal medication with calcium hydroxide, exudation through the canal persisted. Therefore, a periapical surgery was performed with curettage of the lesion, apicectomy and transsurgical obturation associated with AH Plus sealer. After 7 months of follow-up, complete regression of the periapical lesion was observed. In view of the limitations, the success of this case can be attributed to the association of endodontic treatment with the chosen surgical technique, since a repair of the periapical bone radiolucency was observed.

Computational investigation for reduction in auxiliary energy consumption with different cell spacing in battery pack

The need for battery storage systems is expected to grow quickly in the coming decade for a variety of applications, including electric vehicles, stationary storage and off-grid applications. Internal heat production in the lithium-ion battery chemistry is substantial in high-power applications, which is adverse to battery efficiency, long-term performance, and battery safety. Maintaining the battery temperature in the range of 15–45 °C is required for improved performance and safety of lithium-ion battery modules. The cooling methods consist of active and passive cooling, in which active cooling needs of additional power such as liquid cooling, forced air cooling, whereas in passive cooling, there is no need of additional power and employs phase change material cooling, and heat pipe, which require no additional power in the design of Battery thermal management systems. We focused on a designing of a forced-air cooling system for a battery module in this research. A Numerical model of a battery module has been developed in ANSYS Fluent software consist of ECM battery model and validated using the data of the previous study. The novelty of this work is that the subgrouping of the cells in the pack creates turbulence in the flow of heat extracting air. Ability of inlet air to extract heat at an end rows is increased and due to this, the end rows in the pack cool effectively. The modified design shows the improved cooling performance by 21.2 %. The reduced temperature rise in battery pack is achieved without using extra auxiliary power and extra volume. Modified design gives reduction in power consumption by 12.7 %.

The Experiences of Primary Healthcare Nurses During Covid-19 pandemic: Voices from Nursing Staff at King Fahad Specialist Hospital in Buraydah

With the emergence of coronavirus disease (COVID-19), the world has witnessed unprecedented changes in healthcare provision. With the nurses being the most affected healthcare professionals during the pandemic, the current study aimed to examine the experiences of primary healthcare nurses during covid-19 pandemic at King Fahad Specialist Hospital in Buraydah city in the Kingdom of Saudi Arabia. The population of this research consists of all the nurses at King Fahad Specialist Hospital in Buraydah Saudi Arabia whose number is (128) nurses. The target sample included the whole research population using the complete census method. Using the questionnaire as the main data collection tool, the researchers distributed the questionnaire to the target sample and got only (106) complete responses. The duration of the study took about (1) month starting from 01 October 2022 until 02 November 2022. The findings of the study showed that the nurses experienced major employment changes during the pandemic such as extra work hours, the thought of resigning and moving to other clinical areas, and taking long vacations. Also, the findings showed that the nurses experienced major psychological problems such as anxiety, fatigue, and lack of communication, and support from their co-workers and superiors. It has also been reported that the lack of medical suppliers, lack of personal protective equipment, and the extra volume of infected patients served as major challenges experienced by the nurses during the pandemic. The researchers provided a set of recommendations that focused mainly on the importance of organizational intervention and supporting the nurses both psychologically and professionally with an extended focus on training and qualification for the nurses to deal with such crises.

Dynamic and Equilibrium Contribution of Nematic Order in Wetting and Contact Angles

A model for the dynamic contact angles and the spreading kinetics of nematic liquid crystals on a solid surface is presented for the first time using the continuum theory of liquid crystals. The equations of motion for this system are integrated for a wedge or a drop that is thin and moves slowly. The dynamic contact angle is found to depend on the capillary number that represents the importance of viscocapillarity and on the elasticity number that is the ratio between the elastic and surface forces. The model provides an explanation for the extra volume dependence that is reported in experiments, as well as one case of recoil, and for the observation that very small drops were reported to be immobile. For the first time, these previous experimental observations are shown to be due to elastic effects.

100 years flashback

100 years flashback

Transformation strain and volume effect associated with martensitic transformation in polycrystalline Ni49+x+yMn23-xGa28-y Heusler alloys

Combined thermal strain and magnetization measurements were performed in polycrystalline alloys Ni49.31Mn22.76Ga27.93(Ni49), Ni53.00Mn21.04Ga25.96(Ni53) and Ni55.62Mn17.52Ga26.86(Ni55.5) to understand the influence of magnetic field (B) on transformation strain (Δλ) and relative volume change (ω) at martensitic transformation (MT). It is found that during cooling and heating both Ni49 and Ni53 samples undergo a MT while the Ni55.5 sample experiences a coupled magnetostructural transformation (MST). Such a MST can enhance the Δλ and ω whereas thermal hysteresis weakens them, which results in a non-monotonic variation in Δλ: 0.211% (Ni49) → 0.166% (Ni53) → 0.185% (Ni55.5) under B = 0 T. Similar tendency was observed in ω. Besides, the values of Δλ and ω increase with increasing field, partially due to the contribution of magnetic field-induced strain. The maximum value ω = 0.674% was obtained in Ni49 sample under 3 T, indicating that an extra volume space of ∼1% should be needed to avoid the destruction of refrigeration chamber. These findings provide key information for future use of Ni–Mn-Ga alloys in refrigeration engineering field.

Performance in (Ultra-)high-performance liquid chromatography-How to qualify and optimize instruments in practice.

This paper investigates the suitability of an ultra-high-performance liquid chromatography/high-performance liquid chromatography hybrid system for ultra-high-performance liquid chromatography applications. Thus, the effect of extra column band broadening, the gradient system, and the injection system were tested and optimized according to their capabilities. An increase of the theoretical plate number up to a factor of two is achieved by the optimization of the extra column volume into the typical ultra-high-performance liquid chromatography range(<10μl). Moreover, for qualitative purposes injections of volumes typical for ultra-high-performance liquid chromatography methods are precise. Despite this, a lack of precision and accuracy was determined for the gradient system, and the dwell volume meets the typical specification range for conventional HPLC systems. Therefore, hybrid systems are the intercept between both spectra and are limitedly suitable for ultra-high-performance liquid chromatography applications. Another way to approximate ultra-high-performance liquid chromatography performance using a high-performance liquid chromatography system is superficially porous particles. Thus, H/u curves of 5μm superficially porous and 3μm fully porous particles wererecorded in order to determine the effect of the particle technology resulting in comparable performance of the used stationary phases.