Off-line Analysis Research Articles

Offline analysis of secondary formation markers in ambient organic aerosols by liquid chromatography coupled with time-of-flight mass spectrometry

The present study provides a comprehensive assessment of the quantitative analysis by high-performance liquid chromatography coupled with dual orthogonal electrospray ionization time-of-flight mass spectrometry (HPLC-ESI-TOF-MS) of pinene markers, biomass-burning related phenols, and other relevant carboxylic acids in atmospheric aerosol samples. Significant insights into the quantitative determination are offered on the basis of systematic experiments targeting the optimization of chromatographic separation, ionization source, and mass spectrometer performance. After testing three analytical columns, the best separation of the compounds of interest was achieved on a Poroshell 120 ECC18 column (4.6 × 50 mm, 2.7 µm) thermostated at 35 °C, operating in gradient elution mode with 0.1% acetic acid in water and acetonitrile at a 0.8 mL min−1 flow rate. Optimal operational conditions for the ESI-TOF-MS instrument were identified as a 350 °C drying gas temperature, 13 L min−1 drying gas flow rate, 60 psig nebulizer pressure, 3000 V for the ion transfer capillary, 60 V for the skimmer, and 150 V for the fragmentor. Additionally, the matrix effect on the ESI efficiency and the spike recovery factors of the compounds were tested. Method quantification limits can go as low as in the 0.88–48.0 μg L − 1 (3.67–200 pg m − 3, at 120 m3 of sampled air) range. The developed method was shown to be reliable for the quantification of the targeted compounds in real atmospheric aerosol samples. The accuracy in the molecular mass determination of less than 5 ppm and the acquisition in the full scan mode were shown to bring additional insights into the organic constituents in atmospheric aerosols.

Accelerating radiochemistry development: Automated robotic platform for performing up to 64 droplet radiochemical reactions in a morning

The growing discovery and development of novel radiopharmaceuticals and radiolabeling methods requires an increasing capacity for radiochemistry experiments. However, such studies typically rely on radiosynthesizers designed for clinical batch production rather than research, greatly limiting throughput. Two general solutions are being pursued to address this: developing new synthesis optimization algorithms to minimize how many experiments are needed, and developing apparatus with enhanced experiment throughput. We describe here a novel high-throughput system based on performing arrays of droplet-based reactions at 10 μL volume scale in parallel. The automatic robotic platform can perform a set of 64 experiments in ∼3 h (from isotope loading to crude product, plus sampling onto TLC plates), plus ∼1 h for off-line radio-TLC analysis and radioactivity measurements, rather than the weeks or months that would be needed using a conventional system. We show the high repeatability and low crosstalk of the platform and demonstrate optimization studies for two 18F-labeled tracers. This novel automated platform greatly increases the practicality of performing arrays of droplet reactions by eliminating human error, vastly reducing tedium and fatigue, minimizing radiation exposure, and freeing up radiochemist time for other intellectually valuable pursuits.

A Wearable Multisensor Patch for Breathing Pattern Recognition

In this paper, a multisensor patch is presented for the purpose of detecting and recognising the signals produced by human breathing in response to a variety of different body movements. We show that a multisensor patch consisting of an accelerometer and a pressure sensor can simultaneously measure breathing-related inertial motion and muscle stretch with a high degree of accuracy when it is attached close to the diaphragm. To construct the multisensor patch, we relied on commercially available off-the-shelf (COTS) electronic components that were relatively inexpensive. Different breathing motions were analyzed based on the accelerometer and the pressure sensor, including inhale, exhale, normal breathing, and breath hold conditions. The breathing frequency from the accelerometer and the flexible capacitive pressure sensors was found to be 0.2 Hz, and the normal breathing rate from the accelerometer and the pressure sensor was 11 breaths/min. We demonstrate that this new functional device and related approaches allow the identification of breathing patterns that are less cumbersome and tenably more reliable than conventional measures. The proposed multisensor patch holds great potential as a sensing technology in medical applications for the early detection of respiratory changes, one of the most predictive and earliest vital signs for worsening health. The presented methodology can be adapted for mass production of reasonably priced non-invasive breathing pattern detection and off-line analysis.

A comparison between the apical and subcostal view for three-dimensional echocardiographic assessment of right ventricular volumes in pediatric patients.

Accurate measurement of ventricular volumes is an important clinical imaging goal. Three-dimensional echocardiography (3DEcho) is used increasingly as it is more available and less costly than cardiac magnetic resonance (CMR). For the right ventricle (RV), the current practice is to acquire 3DEcho volumes from the apical view. However, in some patients the RV may be better seen from the subcostal view. Therefore, this study compared RV volume measurements from the apical vs. the subcostal view, using CMR as a reference standard. Patients <18 years old undergoing a clinical CMR examination were prospectively enrolled. 3DEcho was performed on the day of the CMR. 3DEcho images were acquired with Philips Epic 7 ultrasound system from apical and subcostal views. Offline analysis was performed with TomTec 4DRV Function for 3DEcho images and cvi42 for CMR ones. RV end-diastolic volume and end-systolic volume were collected. Agreement between 3DEcho and CMR was assessed with Bland-Altman analysis and the intraclass correlation coefficient (ICC). Percentage (%) error was calculated using CMR as the reference standard. Forty-seven patients were included in the analysis (age range 10 months to 16 years). The ICC was moderate to excellent for all volume comparisons to CMR (subcostal vs. CMR: end-diastolic volume 0.93, end-systolic volume 0.81; apical vs. CMR: end-diastolic volume 0.94, end-systolic volume 0.74).The 3DEcho mean % error vs. CMR for end-systolic volume was 25% for subcostal and 31% for apical; for end-diastolic volume it was 15% for subcostal and 16% for apical. The % error was not significantly different between apical vs. subcostal views for end-systolic and end-diastolic volume measurements. For apical and subcostal views, 3DEcho-derived ventricular volumes agree well with CMR. Neither echo view has a consistently smaller error when compared to CMR volumes. Accordingly, the subcostal view can be used as an alternative to the apical view when acquiring 3DEcho volumes in pediatric patients, particularly when the image quality from this window is superior.

Conducting an Analysis of Mosquito Flight Behaviors in a Wind Tunnel.

Prior to conducting wind tunnel experiments, mosquitoes must be prepared for testing. Important factors and state-dependent processes of the mosquito-like the sex, age, infection status, reproductive status, or nutritional status-should be evaluated and motivated by questions and hypotheses one seeks to address. Other critical external factors that can impact the mosquitoes' behavior and should be controlled for both in the colony and in the room where the wind tunnel experiments take place include the circadian rhythm, room temperature, light intensity, and relative humidity. Together, the internal and external factors, and wind tunnel design, ultimately control the behavior of the mosquito and, hence, the success of the experiments. In the present protocol, we describe methods using a standard wind tunnel design in which the fan pulls the air through the working section of the wind tunnel and the mosquito behavior is recorded by a multicamera system. Variations around the camera tracking system can be adapted according to the research questions being asked and include real-time tracking for both closed-loop and open-loop control of the stimulus environment or recording of the videos for off-line digitization and analysis. Within the working section, the sensory environment (odor, visual, wind) can be controlled to test the mosquito responses to different stimuli, and below we include different equipment and tools for modifying the stimuli the mosquito experiences during flight. Finally, the methods described here are applicable to multiple mosquito species, although the experiment parameters may need to be changed (e.g., ambient luminosity).

Sex differences in learning and performing the Go/NoGo tasks

BackgroundThe quality of learning and post-learning performances is critical for daily life. The behavioral flexibility is equally important for adapting the changing circumstances. The learning process requires repeated practices, which enhances prompt and proper behavioral responses, in turn, which promotes habits formation as well. Despite the well-documented sex differences in learning and performances, contradictory results were reported. A possible cause might be a systematic analysis due to specific research interests, regardless of the continuity of natural acquisition process. Here, we investigate the potential sex differences in learning, performances and adjustments of habited behaviors with regular and reversal Go/NoGo tasks.MethodsBoth male and female Sprague-Dawley rats were used in this study. All rats were trained for a regular rodent Go/NoGo task and a subset of rats were trained for a reversal rodent Go/NoGo task, both with strict elimination criteria. The behavioral performance data were stored in PC for off-line analysis. Multiple behavioral indices were analyzed for both passed and retired rats.ResultsThe ability of learning the regular the reversal Go/NoGo tasks was similar for both male and female rats, however, the female rats took longer time to master the task principles in later stages for both tasks. In the regular Go/NoGo task, the female rats spent more time on completing the trial in performance optimization phases, which implied female rats were more cautious than male rats. Along with the progression of training, both male and female rats developed Go-preference strategies to perform the regular Go/NoGo task, which induced failure to meet the setting success criteria. The retired male rats exhibited shorter RTs and MTs than the retired female rats after developing Go-preference. Moreover, the time needed to complete the Go trials was significantly prolonged for male rats in the reversal Go/NoGo task.ConclusionsOverall, we conclude that distinctive strategies were employed in performing Go/NoGo tasks for both male and female rats. Male rats required less time to stabilize the performance in behavioral optimization phase. In addition, male rats were more accurate in estimating time elapsing. In contrast, female rats took more cautious considerations in performing the task, through which minimal influences were manifested in the reversal version of task.

An Offline Calculation and Analysis Method of Chips Patch Efficiency for Dual-Arms Mounter to Guide Parameter Optimization

Since high efficiency and low cost have become the leading trend of semiconductor packaging, dual-arms chips mounters have been widely used to eliminate the time delays and improve the efficiency. However, the auxiliary motion is required to avoid spatial interference, which increases the complexity of trajectory. In addition, the motion parameters need to be constantly adjusted online to balance the chips patch efficiency and operation stability. Whereas chips placement efficiency needs to online monitor, which is laborious, difficult to adjust the motion parameters rapidly. To off-line analyze the packaging efficiency, this paper establishes a calculation model for chips patch efficiency of dual-arms mounter, which accurately establish the quantitative relationship between motion parameters and efficiency, narrowing the selection range of motion parameters. Firstly, the process sequence of chips patch is constructed, and the efficiency calculation model is established. Secondly, considering the characteristics of the time-varying displacement, the method for solving the running time of each process under the flexible velocity control is proposed. Then, the chips patch efficiency is calculated for different parameters, and the effects of the motion parameters and the lead frame structures on chips patch efficiency are investigated, so as to optimize motion parameters. And simulation and calculation results of PTP motion are in good agreement with the experimental results, which provide an effective guidance for accurately calculating chips patch efficiency off-line and lays a foundation for selecting motion parameters.

EN-452414-1 IMPACT OF MULTI-DIRECTIONAL PACING ON LATE SIGNAL ACTIVATION, ACTIVATION SLOWING AND REPOLARIZATION GRADIENTS TO LOCALIZE RE-ENTRANT VENTRICULAR TACHYCARDIA CIRCUITS IN A PORCINE INFARCT MODEL.

Optimal signal parameters and substrate mapping strategies for identifying key arrhythmogenic sites in ventricular tachycardia (VT) ablation are not established. To evaluate multi-directional pacing on the distribution of late signal activation, activation slowing and repolarization gradients in relation to critical sites of re-entrant VT, in a porcine infarct model. Electrophysiology studies were performed 4 weeks post-infarction in 13 pigs using the EnSite Precision system (Abbott, IL, USA), and the Advisor HD Grid (Abbott) multi-electrode catheter. Substrate maps were created during right ventricular (RV), left ventricular (LV), and biventricular pacing (BIV), and sinus rhythm (SR). Sites of early, mid-, and late-diastolic signals of induced VT’s were delineated. Off-line analysis compared these critical VT sites to algorithmically identified 20 most vulnerable sites of latest activation timing within and post-QRS, and the largest activation (GradAT) and activation recovery interval gradients (GradARI). 34 VTs were mapped with at least one diastolic recorded component, with a mean tachycardia cycle length of 236.5 ± 32.4 ms. 48 sinus rhythm and pacing maps were obtained, 10 using BIV pacing (mean points 375 ± 263), 13 using LV pacing (mean points 610 ± 334), 13 from RV pacing (mean points 603 ± 263) and 12 in sinus rhythm (mean points 1078 ± 654). Late potential (LP) mapping in sinus rhythm was taken as the established clinical standard for statistical comparison with all other protocols, displayed in Figure 1. GradARI using RV pacing provided the closest localization for VT exit and entrance, with a median distance of 10.6mm (IQR 5.0mm, p <0.05) and median 9.4mm (IQR 8.0mm, p <0.05) compared to LP in sinus rhythm, respectively. LAT with BIV pacing provided closest VT isthmus localization for VT isthmus, with a median of 5.5mm (IQR 7.15mm, p <0.05) compared to LP in sinus rhythm (Figure 1). A global sensitivity and specificity analysis was performed on all points. GradARI mapping in SR reported the highest AUC (area – under curve) for early diastolic VT signals (AUC 0.96, sensitivity 93%, specificity 91%), mid-diastolic signals (AUC 0.92, sensitivity 84%, specificity 88%) and late diastolic signals (AUC 0.92, sensitivity 88%, specificity 84%). Sites with the largest ARI gradients in sinus rhythm best predict critical sites of VT in this model, with the most effective protocol being RV pacing examining ARI gradients.

On- and off-line analysis by ICP-MS to measure the bioaccessible concentration of elements in PM10 using dynamic versions of the simplified bioaccessibility extraction test.

Two dynamic versions of the simplified bioaccessibility extraction test (SBET) were developed-an off-line procedure and an on-line procedure coupled directly to ICP-MS. Batch, on-line, and off-line procedures were applied to simulated PM10 samples prepared by loading NIST SRM 2711A Montana II Soil and BGS RM 102 Ironstone Soil onto 45-mm TX40 filters widely used in air quality monitoring. Three real PM10 samples were also extracted. A polycarbonate filter holder was used as an extraction unit for the dynamic procedures. Arsenic, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were determined in the extracts using an Agilent 7700 × ICP-MS instrument. The residual simulated PM10 samples following application of the SBET were subjected to microwave-assisted aqua regia digestion and a mass balancecalculation performed with respect to digestion of a separate test portion of the SRM. Leachates were collected as subfractions for the off-line analysis or continuously introduced to the nebuliser of the ICP-MS for the on-line analysis. The mass balance was generally acceptable for all versions of the SBET. Recoveries obtained with the dynamic methods were closer to pseudototal values than those obtained in batch mode. Off-line analysis performed better than on-line analysis, except for Pb. Recoveries of bioaccessible Pb relative to the certified value in NIST SRM 2711A Montana II Soil (1110 ± 49mgkg-1) were 99, 106, and 105% for the batch, off-line, and on-line methods, respectively. The study demonstrates that dynamic SBET can be used to measure bioaccessibility of potentially toxic elements in PM10 samples.

Characterization of reading errors in languages with different orthographic regularity: an Italian–English comparison

The study examined whether a classification of errors based on Hendriks and Kolk’s (1997) proposal would effectively characterize the reading profile of children learning two orthographies varying for regularity, such as Italian and English. The study considered both an age-match and a grade-match comparison. Offline analysis of error production was carried out for two lists of stimuli: List 1 including regular words varying for frequency and matched non-words and List 2 including low-frequency words varying for regularity. In List 1, Italian-reading children made more multiple attempts characterized by a slow and progressive approach to the target (sounding-out behavior) than English-reading children, while the latter made relatively more word substitutions and non-word lexicalizations. As for List 2, Italian-reading children made relatively more multiple attempts and progressive approaches to the target compared to the English-reading children (with more sounding-out behaviors and syllabications), while the opposite occurred for phonological-visual errors, word substitutions, morphological, and semantic errors. Both groups showed a high proportion of phonological-visual and regularization errors (stress assignment in the case of Italian-reading children). Overall, the use of an error coding system specifically tuned to the characteristics of the orthographies investigated allowed a more comprehensive identification of reading difficulties which allowed the different strategies used by children of different languages to emerge more clearly (more reliance on sub-lexical routines in Italian readers and on lexical routines in English readers). These results call for more attention to error patterns in the identification of reading difficulties in children of different languages including those learning a transparent orthography where error analyses have largely been ignored.

Topological charge-sharing background reduction for the Silicon Drift Detectors used by the VIP experiment at LNGS

Large area Silicon Drift Detectors are employed in high sensitivity tests of the Pauli Exclusion Principle by the VIP-2 Collaboration. The experiment is operated in the extremely low cosmic background environment of the Gran Sasso underground National Laboratory of INFN. In this work an off-line analysis method is proposed which provides an additional background reduction, as well as a better calibration procedure. The study concerns in particular the charge sharing between nearby cells, and is applied to the data set collected during the 2018 VIP-2 campaign. The cross-talk effect inside the detectors array is described and an effective topological method to reject the background induced by charge sharing is outlined.

Echocardiographic Study of Left Ventricular Pressure-Strain Loop in Evaluating Changes in Left Ventricular Myocardial Work in Breast Cancer Patients After Chemotherapy.

This study aimed to evaluate the changes in the left ventricular (LV) myocardial work (MW) in breast cancer patients following chemotherapy by left ventricular pressure-strain loop (LVPSL).A total of 50 patients with newly breast cancer undergoing postoperative adjuvant chemotherapy containing anthracycline were selected. Echocardiography was performed before the treatment (T0), the second (T2) and fourth (T4) cycles of chemotherapy, and 3 (P3 m) and 6 (P6 m) months after the end of chemotherapy. The standard dynamic images of the required sections were collected. After off-line analysis, the routine, global myocardial strain, and global MW parameters were obtained, and the average regional MW index (RMWI) and regional MW efficiency (RMWE) at three levels of LV were calculated.Compared with those at T0 and T2, the global work index (GWI), global constructive work (GCW), global work efficiency (GWE), and global longitudinal strain (GLS) gradually decreased and global wasted work (GWW) gradually increased at T4, P0, and P6 m. The mean RMWI and RMWE of the three levels of LV exhibited a gradually decreasing trend at T4, P0, and P6 m compared with those at T0 and T2. The GWI, GCW, GWE, mean RMWI, and RMWE (basal, medial, and apical) were negatively correlated with the GLS (r = -0.76, -0.66, -0.67, -0.76, -0.77, -0.66, -0.67, -0.59, and -0.61, respectively), whereas the GWW was positively correlated with the GLS (r = 0.55).The mean RMWI and RMWE are effective parameters to reflect the cardiotoxicity of LV, and LVPSL has certain value in the evaluation of the left ventricular myocardial work (LVMW) during anthracycline treatment and follow-up in breast cancer patients.

Transmission-error- and vibration-based condition monitoring of gear wear with contaminated lubricant

The presence of contaminant particles in lubricants could cause severe gear wear and damage. Conventional condition monitoring techniques, i.e., gear inspection and oil/wear debris analysis, are often utilised to assess the presence of wear due to contaminants and its severity such as wear depth. However, the traditional approaches require experience or off-line analysis. Although vibration is a non-invasive technique for fault detection and diagnostics, it is less well developed for wear analysis. Recently, an alternative sensor technology, i.e., transmission error (TE), combining angular measurements obtained from the input and output shafts has shown strong potential for wear monitoring. This work aims to investigate the usage of vibration and TE to identify the existence of contaminants and measure the gear wear severity caused by the oil contamination. This is achieved by conducting gear wear tests on a spur gearbox rig, using clean and contaminated lubricants with silica sand. The test in a normal lubrication condition provides a healthy reference of the spur gearbox under a nominal operating condition. In addition to the nominal operating condition, TE and vibration measurements are collected throughout the tests at different operating conditions, together with moulds of the gear tooth surfaces for wear analysis. The results show that the absolute TE can quantitively measure wear depth, and the RMS of vibration can qualitatively correlate with the trend of the average wear depths. The proposed technique extends the field of using TE to diagnose and predict gear wear in contaminated lubricant conditions.

Critical aspects in occupational exposure assessment with different aerosol metrics in an industrial spray coating process

Engineered Nanomaterials (ENMs) have several uses in various industrial fields and are embedded in a myriad of consumer products. However, there is continued concern over the potential adverse health effects and environmental impacts of ENMs due to their unique physico-chemical characteristics. Currently, there are no specific international regulations for various ENMs. There are also no Occupational Exposure Limits (OEL) regulated by the European Union (EU) for nanomaterials in the form of nano-objects, their aggregates or agglomerates (NOAA). For ENMs the question of which metric to be used (i.e., mass, surface area, number concentrations) to determine the exposure is still not resolved. The aim of this work is to assess the worker exposure by inhalation in an industrial spray coating process by using all three metrics mentioned above. Two target ENMs (N-doped TiO2, TiO2N and AgNPs capped with a quaternized hydroxyethyl-cellulose, AgHEC) generated for industrial-scale spraying processes were considered. Results showed that the averaged particle number concentration (10–100 nm) was below 2.7 104 cm−3 for both materials. The Lung Deposited Surface Area (LDSA) was in the range between 73 and 98 μm2cm−3 and the particle mass concentration (obtained by means of ICP-EOS off-line analysis) resulted below 70 μg m−3 and 0.4 μg m−3 for TiO2 and Ag, respectively. Although, the airborne particles concentration compared well with the NIOSH Recommended Exposure Level (REL) limits the contribution to the background, according to EN 17058 (Annex E) was significant (particularly in the particle number and PM1 mass concentrations). We successfully evaluated the worker exposure by means of the different airborne particles' metrics (number, surface and mass concentrations). We concluded that worker exposure assessment involving ENMs is a complex procedure with requires both real time and off-line measurements and a deep investigation of the background.

Infrared spectroscopy for neurochemical monitoring of alcohol and its metabolites.

Continuous measurement of the concentrations of ethanol and its metabolites, acetaldehyde and acetic acid, in vivo is important for the alcohol research community. Most studies only measure ethanol because accurate measurement of all three compounds is challenging. Measurement inside tissue/brain is done using a microdialysis technique, followed by off-line analysis using gas chromatography (GC). To realize simultaneous measurement of ethanol and its metabolites, one can take advantage of infrared (IR) spectroscopy as a rapid and reagent-free method. Here we report a feasibility study of using IR spectroscopy to simultaneously measure ethanol, acetaldehyde and acetic acid in aqueous solution. Different concentrations in transmission mode at different optical pathlengths and using attenuated total reflectance (ATR) were measured. In vitro microdialysis was performed on the mixture of the three compounds, and the collected sample was measured using IR to demonstrate the capability of quantifying the concentrations of the three analytes simultaneously. Lastly, to overcome the limitations of the microdialysis technique, direct measurement using evanescent-field IR spectroscopy can be a potential alternative. A hydrophobic polymer coating that adsorbs ethanol and excludes water, could improve sensitivity. Sorption kinetics in polymethyl methacrylate (PMMA) and polydimethylsiloxane (PDMS) coatings on an ATR crystal were measured. Both polymers demonstrate preferential adsorption of ethanol over water.

Correlation between three-dimensional echocardiography and cardiopulmonary fitness in patients with univentricular heart: A cross-sectional multicentre prospective study

BackgroundThe prognosis of patients with a functional single ventricle has improved, with better cardiopulmonary fitness, health-related quality of life and survival. Conventional echocardiography remains the first-line technique in single ventricle follow-up. Three-dimensional (3D) echocardiography has shown recent value in congenital cardiology, but its ability to predict functional status in patients with a single ventricle remains unknown. AimTo evaluate, in patients with a single ventricle, the association between 3D echocardiography variables and functional status determined by cardiopulmonary fitness. MethodsChildren and adults with a functional single ventricle were prospectively enrolled in this multicentre study. Cardiopulmonary fitness was assessed by cardiopulmonary exercise test, with measures of maximum oxygen uptake (VO2max) and ventilatory efficiency (VE/VCO2 slope). 3D echocardiography was performed with off-line reproducibility analyses, using TomTec Arena™ software. Health-related quality of life was assessed using the SF-36 questionnaire. ResultsA total of 33 patients were screened, and 3D echocardiography analyses were feasible in 22 subjects (mean age 28±9years). 3D echocardiography ejection fraction correlated with percent-predicted VO2max (r=0.64, P<0.01), VE/VCO2 slope (r=–0.41, P=0.05), two-dimensional echocardiography ejection fraction (r=0.55, P<0.01) and health-related quality of life physical functioning dimension (r=0.56, P=0.04). 3D echocardiography indexed end-systolic volume correlated with percent-predicted VO2max (r=–0.45, P=0.03) and VE/VCO2 slope (r=0.65, P<0.01). 3D echocardiography reproducibility was good. ConclusionsSingle ventricle ejection fraction and volumes measured by 3D echocardiography correlated with cardiopulmonary fitness, as determined by two main prognostic cardiopulmonary exercise test variables: VO2max and VE/VCO2 slope. Despite good reproducibility, 3D echocardiography feasibility remained limited. 3D echocardiography may be of value in single ventricle follow-up, provided that the technique and analysis software are improved.

Stimulation of spinal cord according to recorded theta hippocampal rhythm during rat move on treadmill.

Several studies have revealed that after spinal cord injury (SCI), in acute and sub-acute phase the spinal cord neurons below the injury are alive and could stimulate by use of electrical pulses. Spinal cord electrical stimulation could generate movement for paralyzed limbs and is a rehabilitation strategy for paralyzed patients. An innovative idea for controlling spinal cord electrical stimulation onset time is presented in current study. In our method, the time of applying electrical pulse on the spinal cord is according to rat behavioral movement and two movements behaviors are recognized only based on rat EEG theta rhythm on the treadmill line. Briefly, 5 rats were placed on the treadmill and the animals experienced zero or 12m/min speeds. These speeds were recognized based on EEG signals and off-line periodogram analysis. Finally, the electrical stimulation pulses had been applied to the spinal cord if the results of the EEG analysis had detected running behavior. These findings may guide future research in utilizing theta rhythms for the recognition of animal motor behavior and designing electrical stimulation systems based on it.

Sustainable chromatographic purification of milbemectin: Application of high-speed countercurrent chromatography coupled with off-line atmospheric pressure solid analysis probe-high resolution mass spectrometry

Isolation of valuable chemicals is an important process in reagent manufacturing for the pharmaceutical and food science industries. This process is traditionally time-consuming, expensive, and consumes vast amounts of organic solvents. Considering green chemistry and sustainability concerns, we sought to develop a sustainable chromatographic purification methodology for obtaining antibiotics by focusing on the reduction of organic solvent waste generation. Milbemectin (mixture of milbemycin A3 and milbemycin A4) was successfully purified using high-speed countercurrent chromatography (HSCCC) and pure fractions (>98% purity, HPLC) could be identified using the organic solvent fee atmospheric pressure solid analysis probe mass spectrometry (ASAP-MS). The organic solvents required for HSCCC could be redistilled and recycled for continued HSCCC purification, thus reducing the consumption of organic solvent (n-hexane/ethyl acetate) by 80+%. Optimization of the two-phase solvent system (n-hexane/ethyl acetate/methanol/water, 9/1/7/3, v/v/v/v) for HSCCC was assisted computationally, thereby reducing solvent waste from an experimental determination. Our proposal application of HSCCC and offline ASAP-MS provides proof of concept for a sustainable, preparative scale, chromatographic purification methodology for obtaining antibiotics in high purity.

Ocena funkcji prawego przedsionka za pomocą echokardiografii metodą śledzenia markerów akustycznych

Introduction. Speckle tracking echocardiography (STE) is a well-established tool to assess cardiac function parameters, however, the value of this tool in the assessment of right atrial (RA) function is still largely unknown. The aim of the study is to investigate the feasibility of RA function assessment by STE and the relationship between right ventricular (RV) deformation and the function of the RA. Material and methods. 94 patients with various cardiovascular pathologies have been included in the study group. All patients underwent transthoracic echocardiography with subsequent off-line analysis using speckle tracking technique and measurement of numerous RA deformation parameters, including peak atrial longitudinal strain (PALS) and peak atrial contraction strain (PACS), as well as established indices of RV function, such as tricuspid annular peak systolic excursion (TAPSE) and global longitudinal strain (GLS). Results. RA function assessment by STE was feasible in all patients. A statistically significant correlation was observed between RA strain (PACS and PALS) and RV parameters. RV-GLS showed weak correlation with PALS (r = –0.38; p = 0.0015) and PACS (r = –0.30; p = 0.013). Similarly, TAPSE correlated with PALS and PACS (r = 0.34; p = 0.02) and (r = 0.23; p = 0.04) respectively. Conclusion. RA function assessment by STE is feasible. The RA deformation parameters weakly correlate with RV function indices, indicating that other factors significantly influence RA function. Therefore, the RA function cannot be regarded as a direct barometer of the RV function.

High-resolution structural-functional substrate-trigger characterization: Future roadmap for catheter ablation of ventricular tachycardia.

Patients with ventricular tachyarrhythmias (VT) are at high risk of sudden cardiac death. When appropriate, catheter ablation is modestly effective, with relatively high VT recurrence and complication rates. Personalized models that incorporate imaging and computational approaches have advanced VT management. However, 3D patient-specific functional electrical information is typically not considered. We hypothesize that incorporating non-invasive 3D electrical and structural characterization in a patient-specific model improves VT-substrate recognition and ablation targeting. In a 53-year-old male with ischemic cardiomyopathy and recurrent monomorphic VT, we built a structural-functional model based on high-resolution 3D late-gadolinium enhancement (LGE) cardiac magnetic resonance imaging (3D-LGE CMR), multi-detector computed tomography (CT), and electrocardiographic imaging (ECGI). Invasive data from high-density contact and pace mapping obtained during endocardial VT-substrate modification were also incorporated. The integrated 3D electro-anatomic model was analyzed off-line. Merging the invasive voltage maps and 3D-LGE CMR endocardial geometry led to a mean Euclidean node-to-node distance of 5 ± 2 mm. Inferolateral and apical areas of low bipolar voltage (<1.5 mV) were associated with high 3D-LGE CMR signal intensity (>0.4) and with higher transmurality of fibrosis. Areas of functional conduction delay or block (evoked delayed potentials, EDPs) were in close proximity to 3D-LGE CMR-derived heterogeneous tissue corridors. ECGI pinpointed the epicardial VT exit at ∼10 mm from the endocardial site of origin, both juxtaposed to the distal ends of two heterogeneous tissue corridors in the inferobasal left ventricle. Radiofrequency ablation at the entrances of these corridors, eliminating all EDPs, and at the VT site of origin rendered the patient non-inducible and arrhythmia-free until the present day (20 months follow-up). Off-line analysis in our model uncovered dynamic electrical instability of the LV inferolateral heterogeneous scar region which set the stage for an evolving VT circuit. We developed a personalized 3D model that integrates high-resolution structural and electrical information and allows the investigation of their dynamic interaction during arrhythmia formation. This model enhances our mechanistic understanding of scar-related VT and provides an advanced, non-invasive roadmap for catheter ablation.