Effective Volume Research Articles

The Repeatability of Pharyngeal Opening Pressure Under Drug-Induced Sleep Endoscopy.

Pharyngeal opening pressure (PhOP) is a measure of upper airway collapsibility that can be obtained during drug-induced sleep endoscopy (DISE) using a continuous positive airway pressure (CPAP) titration. However, the stability of PhOP over the course of sedation during DISE remains unclear. This study aims to compare repeat measures of PhOP over the course of DISE. Single arm prospective study. Single tertiary care institution. Patients had 2 CPAP titrations while undergoing DISE. Collected data included patient demographics, PhOP, patient sedation index (PSI), and duration of and between CPAP titrations. t Tests, test-retest coefficient analysis, and repeated measures correlation were performed. Twenty-five patients completed the study between 2022 and 2023 with 22 patients having sedation depth (PSI) recording. Most were male (76%), obese (average body mass index: 30.24 kg/m2), with severe obstructive sleep apnea (average apnea-hypopnea index: 39.8 events/hr). Test-retest analysis showed good-excellent correlation between PhOP values (intraclass correlation coefficient = 0.892, P < .0001, n = 25). Average time between CPAP titrations was 15 minutes to 6 seconds. Over that time, PhOP increased by an average of 0.72 cmH2O (P = .06, n = 25) and PSI decreased by 9.5 units (P = .01, n = 22). Repeated measures correlation showed a weak negative correlation between PhOP and PSI (r = -.45, P = .03, n = 22). The results showed repeatability of PhOP values over the course of DISE. When adjusted for sedation depth (PSI), deeper sedation was weakly associated with greater PHOP. However, the magnitude of this change was small and we conclude that PhOP remains relatively stable over the course of DISE (Effects of Lung Volume on Upper Airway Patency During DISE [DISE-Pulm], NCT05350332, clinicaltrials.gov).

Polyethylene Glycol Impacts Conformation and Dynamics of Escherichia coli Prolyl-tRNA Synthetase Via Crowding and Confinement Effects.

Polyethylene glycol (PEG) is a flexible, nontoxic polymer commonly used in biological and medical research, and it is generally regarded as biologically inert. PEG molecules of variable sizes are also used as crowding agents to mimic intracellular environments. A recent study with PEG crowders revealed decreased catalytic activity of Escherichia coli prolyl-tRNA synthetase (Ec ProRS), where the smaller molecular weight PEGs had the maximum impact. The molecular mechanism of the crowding effects of PEGs is not clearly understood. PEG may impact protein conformation and dynamics, thus its function. In the present study, the effects of PEG molecules of various molecular weights and concentrations on the conformation and dynamics of Ec ProRS were investigated using a combined experimental and computational approach including intrinsic tryptophan fluorescence spectroscopy, atomic force microscopy, and atomistic molecular dynamic simulations. Results of the present study suggest that lower molecular weight PEGs in the dilute regime have modest effects on the conformational dynamics of Ec ProRS but impact the catalytic function primarily via the excluded volume effect; they form large clusters blocking the active site pocket. In contrast, the larger molecular weight PEGs in dilute to semidilute regimes have a significant impact on the protein's conformational dynamics; they wrap on the protein surface through noncovalent interactions. Thus, lower-molecular-weight PEG molecules impact protein dynamics and function via crowding effects, whereas larger PEGs induce confinement effects. These results have implications for the development of inhibitors for protein targets in a crowded cellular environment.

Computer vision-based measurement of pure- and mixed-gas swelling in polymer membranes: Individual and synergistic effects of configurational free volume and thermal rearrangement

Although polymer swelling (i.e., dilation) data are crucial to assess the long-term stability of polymer membranes and correct sorption isotherms for highly sorbing penetrants, the swelling propensity of new generation membranes exhibiting configurational free volume (i.e, triptycene units) has never been investigated. To fill this gap, in this paper we study pure and mixed-gas swelling of a series of thermally rearranged polybenzoxazoles (TPBOs) and their poly(o-hydroxyimide) precursors exhibiting systematically varied amount of configurational free volume. The individual and synergistic effects of configurational free volume and thermal rearrangement on the polymer swelling propensity are presented and discussed. To do so, we use a newly developed experimental approach based on computer vision, which is capable of correcting most of the limitations of traditional methods used to measure swelling and achieve superior accuracy. We show that thermally rearranged glassy polymers exhibiting configurational free volume exhibit better swelling resistance relative to conventional polymers. The fundamental origin of this behavior resides, as explained by the dual mode theory, on the fact that the Langmuir's mode swelling propensity in thermally rearranged triptycene-based polymers is much lower than in glassy polymers exhibiting only conformational free volume. Differences between pure-gas and mixed-gas induced swelling are also highlighted and discussed. Finally, a thorough investigation of the swelling measurement uncertainty and precision is provided and discussed, including an analysis of the major factors affecting experimental uncertainty.

Evaluation of nanolayer and particle size on fluid transport through rotating disks

AbstractIn this paper, the impact of nanolayer which shows the relationship between the nanoparticle and pure fluid is investigated on the fluid transport and thermal transfer through a rotating system. The nanolayer shows the relationship between the nanoparticle and base liquid, signifying a higher thermal conductivity than the nanoparticle and lower conductivity than the base fluid. Also, the effect of larger nanoparticle size and volume on fluid thermal distribution is considered. The nanoparticle raises the fluid thermal conductivity with the aim of conserving thermal transfer during fluid transport, consequently saving energy. The mechanics of the fluid is developed using a higher‐order coupled system of nonlinear models, solved with the aid of the Homotopy perturbation method. Obtained results from the analysis show the impact of nanolayer expansion on thermal distribution increases boundary layer thickness. Also, the size of the nanoparticle when varied from 10 to 40 nm shows a heat transfer increase of 17.02% at the center of the disk. Particle size increase indicates temperature rise as nanolayer size encompassing the nanoparticle increases. Obtained results when compared against literature give good agreement. The study finds useful applications in coolant and lubricant processing amongst other practical applications.

Is ultrafiltration volume a predictor of postoperative acute kidney injury in patients undergoing cardiopulmonary bypass?

Intraoperative ultrafiltration (UF) is a procedure used during cardiopulmonary bypass (CPB) to reduce haemodilution and prevent excessive blood transfusion. However, the effect of UF volume on acute kidney injury (AKI) is not well established, and the results are conflicting. Additionally, there are no set indications for applying UF during CPB. This retrospective study analysed 641 patients who underwent coronary artery bypass graft (CABG) surgery with CPB. Perioperative parameters were extracted from the patients' records, and the UF volume was recorded. Acute Kidney Injury Network classification was used to define AKI. Univariable and multivariable logistic regression models were used to predict AKI while controlling for confounding factors. The study enrolled patients with a mean age of 58.8 ± 11.1 years, 39.2% of whom were female. AKI occurred in 22.5% of patients, with 16.1% (103) experiencing stage I and 6.4% (41) experiencing stage II. The results showed a significant association between UF volume and the risk of developing AKI, with higher UF volumes associated with a higher risk of AKI. In the multivariable analysis, the other predictors of AKI included age, lowest mean arterial pressure (MAP), and red blood cell (RBC) transfusion during CPB. The predictors of postoperative AKI in coronary CABG patients were the volume of UF, age, MAP, and blood transfusion during CPB.

The effects of the traffic signs information volume on the visual characteristics and workload of novice and experienced drivers

BACKGROUND: The effects of traffic sign information volume (TSIV) on the visual characteristics and workload of novice and experienced drivers were investigated in this study. TSIV plays a crucial role in road traffic safety, and understanding its impact on drivers is essential for designing effective traffic sign systems. OBJECTIVE: This research aimed to compare the visual characteristics and workload of novice and experienced drivers under varying TSIV doses through simulated driving tests. The objective was to provide insights for optimizing the design of road TSIV. METHODS: Six TSIV levels were considered: S0, S1, S2, S3, S4, and S5, representing different workload levels. Participants, including both novice and experienced drivers, were involved in simulated driving scenarios with varying TSIV levels. Eye movement data was collected using an eye tracker device. The study was conducted in China, and appropriate driving simulators and equipment were utilized. RESULTS: The findings revealed several valuable results. Experienced drivers exhibited a higher proportion of saccade behavior in the 30–90 ms time period and did not show rapid saccade behavior during the 0–30 ms period, indicating superior visual search strategies. Both novice and experienced drivers demonstrated improved visual cognitive abilities at the S3 level of TSIV, which corresponds to normal and safe driving conditions. Furthermore, a majority of both groups had saccade amplitudes in the range of 0°–4°, with experienced drivers showing a slightly higher proportion. About 82% of experienced drivers had saccade behavior within the range of 0°–2°, compared to 75% of novice drivers. CONCLUSIONS: The study concludes that the S3 level of TSIV, corresponding to 30 bits/km, is optimal for both novice and experienced drivers. This level promotes better visual performance and reduces visual workload, indicating that drivers’ information acquisition capacity and visual search strategies are maximized while keeping the workload associated with driving at a minimum. These findings have significant implications for enhancing driving safety.

Understanding the pavement project failures in Pakistan: identifying causes and solutions

Pavement deterioration is a major issue in Pakistan's road and highway infrastructure. The current study attempts to clarify the most important factors of road degradation in Pakistan using a questionnaire prepared and distributed to engineers, contractors, architects, surveyors, and project managers involved in road development and upkeep. The study had 147 replies. This data was collected from employees from various road construction sectors in Pakistan. Convenience sampling, a sort of non-probability sampling, is used for data gathering due to time and resource constraints. The data were analysed through SPSS and Microsoft Excel. The responses were gathered using a 10-point Likert scale. The standard (inadequate density in surface or sub-base) has the maximum rank of 9.1, while the lowest factor (use of naturally smooth uncrushed aggregate) is 2.0. Furthermore, the causes of deterioration were reorganised into eight consistent groups of pertinent causes. The first group (effect of traffic load and volume) has a severity level of 6.5, while the last group (effect of bond between layers) ranks 3.22 in group comparison. The study is helpful in identifying the causes of road deterioration in Pakistan and avoiding or mitigating their effects during design, construction, and maintenance through operation.

Theoretical study of the effect of orientations and fibre volume on the thermal insulation capability of reinforced polymer composites

Abstract In industry, synthetic fibre reinforcements are popular due to their cost-effectiveness and lightweight nature. However, the non-reusability and non-degradability have raised environmental concerns and prompted scientists to explore more environmentally friendly alternatives. Natural fibres are being investigated as potential replacements to address these issues and promote sustainability. This study investigated the effect of fibre loading and orientation on the heat conductivity of polymer resins using a finite element-based numerical model developed in our previous research. The numerical analysis was conducted in ANSYS® modelling and simulation using glass and sisal fibres in combination with three distinct matrix materials (epoxy, polyester, and vinyl ester). Different orientations (parallel, perpendicular, 45°, and normal) and volume of fibre fractions (20–35%) were used for the analysis. The properties of the materials were incorporated into the ANSYS Engineering database, and the composite model was divided into five segments to analyse the heat transfer. The thermal boundary condition was implemented by keeping one side of the cylinder at 120°C. The results showed that the thermal conductivity of the composites decreased as the volume fraction of natural fibres increased. Epoxy-based composites exhibited better insulation performance than polyester and vinyl ester-based composites. This study demonstrated the potential of using natural fibres to improve the thermal insulation properties of composites.

Evaluating the Effect of Extra-Cerebral Off-Target Binding in [F-18]MK6240 PET Scans in Early-Stage Alzheimer’s Disease

Abstract [F-18]MK6240 is a PET radioligand with favorable imaging characteristics for measuring tau aggregation in Alzheimer’s disease (AD). In this study we investigated the impact of extra-cerebral off-target binding (ECB) in the meninges and sinus present in [F-18]MK6240 PET scans on quantifying tau burden in preclinical AD. Based on large cohort data from 433 [F-18]MK6240 scans acquired at the University of Wisconsin-Madison, simulations were conducted to examine the range of effects of ECB by varying the ECB profile and input radiotracer concentration curves on areas of early tau accumulation in AD. The range and patterning of ECB in the imaging cohort had high variability between participants, however, 35% revealed moderate to high meningeal signal that could influence quantification. Partial volume effects, which can lead to measured PET signal from neighboring regions influencing signal in adjacent areas of interest, were examined in the simulated images. The simulations demonstrate that signal from the sinus increases the neighboring entorhinal cortex region (ERC) signal and activity detected from the meninges can similarly influence the inferior cerebellar grey matter reference region. ECB effects from the sinus were most prevalent in our cohort, and simulations with the average ECB profile had ERC uptake (SUV) 23% higher than simulations with no ECB. Spill-in effects from the sinus, which increases the medial and ventral temporal cortex SUVR, and spill-in from the meninges into the cerebellar reference region, which leads to a reduction in global SUVR, act in opposite directions, complicating the interpretation of the derived SUVR of [F-18]MK6240 images. These simulation results quantify the effects of ECB in [F-18]MK6240 scans and introduce correction factors to minimize bias of the SUVR measure.

Conical Structures on the Liquid Surface in an Electric Field: Effect of Volume and Surface Charges

Conical Structures on the Liquid Surface in an Electric Field: Effect of Volume and Surface Charges

Center-level outcomes following elective fenestrated endovascular aortic aneurysm repair in the Vascular Quality Initiative database

ObjectiveHospital volume is associated with mortality after open aortic aneurysm repair. Fenestrated and branched endovascular aortic repair (B-FEVAR) has been increasingly used for repair of complex thoracoabdominal and juxtarenal aneurysms, but evidence of a center-volume relationship is limited. We aimed to measure the association of center volume with in-hospital mortality, postoperative outcomes, and 1-year survival following B-FEVAR. MethodsPatients undergoing elective endovascular thoracoabdominal and complex abdominal aneurysm repair with branch intervention (2014-2021) listed within the national Vascular Quality Initiative Thoracic Endovascular Aortic Repair/Complex EVAR database were analyzed. Centers were grouped into quartiles by mean annual procedure volume. Multivariable regression was used to evaluate the effect of center volume on in-hospital mortality adjusting for baseline and procedural characteristics. Kaplan-Meier estimation, log rank test, and mixed effects Cox regression were used to evaluate 1-year survival. ResultsA total of 4302 adult elective F-BEVAR procedures were identified at a total of 163 centers. In-hospital mortality did not differ by hospital volume (quartile [Q]1 = 35/1059 [3.3%]; Q2 = 30/1063 [2.8%]; Q3 = 33/1120 [2.9%]; and Q4 = 44/1060 [4.2%]; P = .308). The high volume group had a higher rate of major complication (Q1 = 14.9%; Q2 = 12.8%; Q3 = 13.3%; and Q4 = 20.1%; adjusted P < .001). Physician-modified grafts were more frequently employed in high-volume centers (Q1 = 4.5%; Q2 = 18.7%; Q3 = 11.3%; and Q4 = 19.2%; P < .001), with a decreased incidence of any endoleak noted at the end of the procedure (Q1 = 34.9%; Q2 = 32.8%; Q3 = 30.0%; and Q4 = 29.0%; P = .003). In the multivariable analysis, in-hospital mortality was not associated with center volume, comparing very low volume to medium- and high-volume centers (odds ratio [95% confidence interval] vs Q4: Q1 = 1.1 [0.6-1.9], Q2 = 0.6 [0.4-1.1], and Q3 = 0.9 [0.5-1.5]; all P > .05). No significant difference was found in 1-year survival between center volume groups. ConclusionsIn-hospital mortality is not associated with procedure volume within centers performing complex endovascular aortic repair. However, complication rates and endoleak may be associated with procedure volume. Long-term outcomes by annualized procedure volume, specifically graft durability and sac expansion, should be investigated.

Experimental study of effects of buffer tank volume on pressure pulsation in valved linear compressor's pipe system at different frequencies

Experimental study of effects of buffer tank volume on pressure pulsation in valved linear compressor's pipe system at different frequencies

Short-term fate of nitrogen fixed by moss-cyanobacteria associations under different rainfall regimes

Nitrogen (N) fixation by moss-cyanobacteria associations has been recognized as an important N input pathway in many ecosystems from arctic tundra to tropical forests. However, the transfer of fixed N2 from mosses to the soil as well as the effects of rainfall frequency and volume on this N transfer has hardly been studied – even though mosses can leach nutrients upon rewetting. In this study, we investigated the transfer of fixed N2 by moss-cyanobacteria associations in one month under four watering regimes with a combination of high and low volume and frequency. For this, we used two morphologically similar moss species collected from ecosystems with different climate and N availability (subarctic - Hylocomium splendens; and tropical - Thuidium delicatulum). Acetylene reduction assays were conducted as a measure of N2 fixation rates in mosses, and 15N-N2 tracing was used to follow the fixed N2 from moss to the underlying substrate. Nitrogen fixation rates were higher in T. delicatulum than in H. splendens, but rainfall volume and frequency did not show strong effects on N2 fixation rates. Nonetheless, the extent of N leached from mosses was more sensitive to an increase in rainfall volume than to an increase in frequency, and more N was lost from T. delicatulum under high volume precipitation than from H. splendens. Both total nitrogen and 15N enrichment results demonstrate that the fixed N2 was mostly stored in moss tissues with less than 1 % leached to the substrate. Our results show that both moss species retain almost all fixed N2 within their tissues under small rainfall disturbances within one month, while increased N availability under higher precipitation volume renders some moss species an important N source for the soil.

Determination of 222 pesticide residues in olive oil by fully automatic QuEChERS pre-treatment instrument coupled with gas chromatography-quadrupole-time-of-flight mass spectrometry

Pesticide residues may be present in olive oil because pesticides are applied to olive trees during their cultivation and growth for pest prevention and some of these pesticides are not easily degraded. Studies on pesticide residues in olive oil have mainly focused on the detection of single types of pesticide residues, and reports on the simultaneous detection of multiple pesticide residues are limited. At present, hundreds of pesticides with different polarities and chemical properties are used in practice. In this study, an analytical method based on fully automatic QuEChERS pretreatment instrument coupled with gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOF-MS) was established for the rapid determination of 222 pesticide residues in olive oil. The effects of acetonitrile acidification concentration, n-hexane volume, oscillation time, centrifugation temperature, and purification agent on the determination of the 222 pesticide residues were investigated. First, ions with good responses and no obvious interference were selected for quantification and characterization. The purification process was then developed by setting the parameters of the fully automatic QuEChERS pretreatment instrument to optimal values. The sample was extracted with acetonitrile containing 2% formic acid, and the supernatant was purified by centrifugation in a centrifuge tube containing 400 mg N-propylethylenediamine (PSA), 400 mg octadecylsilane-bonded silica gel (C18), and 1200 mg anhydrous magnesium sulfate. The purified solution was blown dry with nitrogen and then fixed with ethyl acetate for instrumental analysis. Finally, a matrix standard solution was used for quantification. The method was validated in terms of matrix effects, linear ranges, limits of detection (LODs) and quantification (LOQs), accuracies, and precisions. The results showed that 86.04% of the 222 pesticides had linear ranges of 0.02-2.00 μg/mL, 10.81% had linear ranges of 0.10-2.00 μg/mL, and 3.15% had linear ranges of 0.20-2.00 μg/mL. The pesticide residues showed good relationships within their respective linear ranges, and the correlation coefficients (R2) were greater than 0.99. The LODs of all tested pesticides ranged from 0.002 to 0.050 mg/kg, and their LOQs ranged from 0.007 to 0.167 mg/kg. Among the 222 pesticides determined, 170 pesticides had LOQs of 0.007 mg/kg while 21 pesticides had LOQs of 0.017 mg/kg. At the three spiked levels of 0.2, 0.5, and 0.8 mg/kg, 79.58% of all tested pesticides had average recoveries of 70%-120% while 65.92% had average recoveries of 80%-110%. In addition, 93.54% of all tested pesticides had relative standard deviations (RSDs, n=6)<10% while 98.35% had RSDs (n=6)<20%. The method was applied to 14 commercially available olive oil samples, and seven pesticides were detected in the range of 0.0044-0.0490 mg/kg. The residues of fenbuconazole, chlorpyrifos, and methoprene did not exceed the maximum limits stated in GB 2763-2021. The maximum residual limits of molinate, monolinuron, benalaxyl, and thiobencarb have not been established. The method utilizes the high mass resolution capability of TOF-MS, which can improve the detection throughput while ensuring good sensitivity. In addition, high-resolution and accurate mass measurements render the screening results more reliable, which is necessary for the high-throughput detection of pesticide residues. The use of a fully automatic QuEChERS instrument in the pretreatment step reduces personnel errors and labor costs, especially when a large number of samples must be processed, thereby offering significant advantages over other approaches. Moreover, the method is simple, rapid, sensitive, highly automatable, accurate, and precise. Thus, it meets requirements for the high-throughput detection of pesticide residues in olive oil and provides a reference for the development of detection methods for pesticide residues in other types of oils as well as the automatic pretreatment of complex matrices.

A Self-Powered Biochemical Sensor for Intelligent Agriculture Enabled by Signal Enhanced Triboelectric Nanogenerator.

Precise agriculture based on intelligent agriculture plays a significant role in sustainable development. The agricultural Internet of Things (IoTs) is a crucial foundation for intelligent agriculture. However, the development of agricultural IoTs has led to exponential growth in various sensors, posing a major challenge in achieving long-term stable power supply for these distributed sensors. Introducing a self-powered active biochemical sensor can help, but current sensors have poor sensitivity and specificity making this application challenging. To overcome this limitation, a triboelectric nanogenerator (TENG)-based self-powered active urea sensor which demonstrates high sensitivity and specificity is developed. This device achieves signal enhancement by introducing a volume effect to enhance the utilization of charges through a novel dual-electrode structure, and improves the specificity of urea detection by utilizing an enzyme-catalyzed reaction. The device is successfully used to monitor the variation of urea concentration during crop growth with concentrations as low as 4µm, without being significantly affected by common fertilizers such as potassium chloride or ammonium dihydrogen phosphate. This is the first self-powered active biochemical sensor capable of highly specific and highly sensitive fertilizer detection, pointing toward a new direction for developing self-powered active biochemical sensor systems within sustainable development-oriented agricultural IoTs.

Dose-Response Effect of an Inertia Flywheel Postactivation Performance Enhancement Protocol on Countermovement Jump Performance.

The purpose of this study was to investigate the dose-response effect of a high-load, 6-repetition, maximum effort inertial flywheel (IFw) squat postactivation performance enhancement (PAPE) protocol on countermovement jump (CMJ) performance metrics. Thirteen subjects completed 5 squat testing sessions: 1 session to determine back-squat 6-repetition maximum, 1 session to determine 6-repetition maximum IFw load, and 3 sessions to investigate the dose-response effect of an IFw PAPE protocol set at the load determined in the second session. In the IFw PAPE sessions, subjects completed either 1, 2, or 3 sets of IFw squats, then performed 5 CMJs over 12minutes (1, 3, 6, 9, and 12min post-IFw). All CMJ tests were conducted on a force platform where CMJ performance outcomes and impulse variables were calculated. There was no main time or volume effect for jump height, contact time, reactive strength index, peak force, or any of the impulse variables. A main time effect was identified for flight time (P = .006, effect size = 0.24) and peak power (P = .001, effect size = 0.28). The lack of change in jump height may indicate that too much fatigue was generated following this near-maximal IFw squat protocol, thereby reducing the PAPE effect.

374 Feasibility of Postoperative Diffusion Weighted Imaging to Assess Neural Recovery in Cervical Spondylotic Myelopathy

INTRODUCTION: Following decompressive surgery for cervical spondylotic myelopathy (CSM), advanced diffusion-weighted MRI, such as diffusion basis spectrum imaging (DBSI), may hold significant value by quantifying and tracking spinal cord microstructure. However, there is a paucity of studies investigating this topic, likely due to challenges in resolving signal distortions from spinal instrumentation. METHODS: A single-center prospective study enrolled 50 CSM patients and 20 control patients. All patients underwent preoperative and repeat diffusion-weighted MRI at two-year follow-up. All CSM patients underwent decompressive cervical surgery. DBSI metrics were extracted from the C3 spinal cord level only to minimize image artifact and reduce partial volume effects. DBSI anisotropic tensors evaluated white matter tracts through fractional anisotropy, axial diffusivity, radial diffusivity, and fiber fraction. DBSI isotropic tensors assessed extra-axonal pathology through restricted and non-restricted fraction. RESULTS: Of 50 CSM patients, 27 patients underwent both baseline and postoperative diffusion-weighted MRI scans with sufficient quality for analysis. This included 15 mild, 7 moderate, and 5 severe CSM patients, who were followed up to 23.2 (5.6, range 11.1-32.8) months. All preoperative C3 DBSI measures were significantly different between CSM and control patients (p &lt; 0.001), except DBSI fractional anisotropy (p = 0.31). At two-year follow-up, the same significance pattern was found, except DBSI radial diffusivity lost statistical significance (p = 0.75). When assessing change in C3 DBSI measures, CSM patients exhibited significant decreases in DBSI radial diffusivity (p = 0.02). Among control patients, there was no significant difference in DBSI metrics between timepoints. CONCLUSIONS: DBSI may have potential in the postoperative setting to inform clinicians of white matter tract recovery after decompressive cervical surgery for CSM.

Evaluation of Lentiviral Based Gene Delivery System in Adherent and Suspension in vitro Cell Models

Lentiviruses are a highly robust gene delivery system capable of in vitro and in vivo gene transfer into multiple cell types. Recent fourth-generation lentiviral systems have been designed for enhanced safety, however, the increased recombination events required to produce infective lentiviral particles may reduce production efficiency. A set protocol for all types of target cells is not recommended and optimization of conditions for gene transfer into different target cells is required. In this study, we aim to evaluate the efficiency and reproducibility of lentiviral production using a fourth-generation lentiviral packaging system and identify optimal parameters for successful transduction in two different cell models, adherent and suspension cells. Lentiviral production, effect of viral volume, sustained gene expression and transduction adjuvants on adherent and suspension gene- cell models were evaluated. Transfection and transduction efficiency of lentiviruses was evaluated by fluorescence microscopy and flow cytometry. This study demonstrates that production of green fluorescent protein (GFP)- lentiviruses using the fourth-generation lentiviral packaging is consistent and reproducible. Optimal transduction of adherent cell types is achieved at lower multiplicity of infection (MOI) compared to suspension cells and produces GFP-expressing cells with higher intensity. Expression of GFP is sustained in all cell types over multiple passages. Polycation DEAE-dextran was determined to improve transduction in suspension cells, however, provides similar transduction efficiency as polybrene in adherent cells. In conclusion, fourth generation lentiviral system reproducibly generates high titre lentiviruses capable of infecting multiple cell types, however transduction protocols for different cell types require further optimization.

Foreign Dependency and Economic Growth Nexus in Kenya

Foreign dependency is an economic phenomenon, which is characterized by asymmetrical benefits, favouring specific countries at the expense of others, and impeding the growth potential of dependent economies. The main objective of the study was to determine the relationship between foreign dependency and economic growth in Kenya. To achieve this overarching aim, specific objectives have been delineated to include an evaluation of the effect of import volumes and external debt levels on economic growth in Kenya. The theoretical underpinnings of this study draw from several key economic theories and models, each offering unique insights into the dynamics of foreign dependency. This study employed a descriptive and inferential statistical design and leverages a time series dataset spanning the years 1980 to 2021, meticulously sourced from the World Bank. To facilitate a comprehensive analysis, the Autoregressive Distributed Lag (ARDL) model was applied. The empirical analysis revealed noteworthy relationships between determinants of economic growth in the Kenyan context. Specifically, imports of goods and services and external debt are all identified as having statistically significant impacts on the trajectory of economic growth in Kenya. In conclusion, these findings suggest that factors like imports and external debt contributes positively to economic growth. The study recommends that policymakers should explore strategies to attract productive external debt which will stimulate positive investment spillover effects within the economy. Emphasis should be placed on the need to bolster the import-led growth through regulatory mechanisms that safeguard local producers. Responsible external debt management is underscored as pivotal to fostering sustained and robust economic growth. Additionally, trade policies designed to facilitate import-led growth are posited as potentially beneficial for the Kenyan economy.

False positive findings associated with adenoviral vector-based vaccine underscore the regulatory necessity to eliminate abnormal toxicity test

Accumulating evidence has shown that the abnormal toxicity test (ATT) is not suitable as a quality control batch release test for biologics and vaccines. The purpose of the current study was to explore the optimal ATT experimental design for an adenoviral vector-based vaccine product to avoid false positive results following the standard test conditions stipulated in the Pharmacopoeias. ATT were conducted in both mice and guinea pigs based on methods in Pharmacopeias, with modifications to assess effects of dose volume and amount of virus particles (VPs). The results showed intraperitoneal (IP) dosing at human relevant dose and volume (i.e., VPs), as required by pharmacopeia study design, resulted in false positive findings not associated with extraneous contaminants of a product. Considering many gene therapy products use adeno associated virus as the platform for transgene delivery, data from this study are highly relevant in providing convincing evidence to show the ATT is inappropriate as batch release test for biologics, vaccine and gene therapy products. In conclusion, ATT, which requires unnecessary animal usage and competes for resources which otherwise can be spent on innovative medicine research, should be deleted permanently as batch release test by regulatory authorities around the world.