bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Dynamic(s) of Adipose Stem Cell System, Their Survival, and Cessation under the Influence of Electromagnetic Fields
Authors: Trzyna Anna , Bądziul Dorota B. , Jakubczyk Paweł , Bocak Damian S. , Cholewa Marian , Banaś-Ząbczyk Agnieszka 
Published: May 2024

Context
The electromagnetic field (EMF) is one of the external biophysical factors that can influence stem cells' structure and functionality. Depending on its frequency and magnetic flux density, EMF can have both a positive and negative effect on stem cell biology.

Aims:
The aim of the study is to define EMF conditions that support beneficial physiological processes and those that lead to pathophysiological phenomena. Understanding the changes and processes occurring in stem cells after exposure to EMFs of different parameters can be an important factor to be applied in stem cell-based therapies and regenerative medicine.

Materials and Methods:
In this study, using fluorescent microscopy and flow cytometry methods, the influence of EMF on adipose-derived stem cells proliferation, cell cycle, viability, and death were examined. EMF parameters were set in accordance with the ion cyclotron resonance (ICR) theory that influences Ca2+ and Mg2+ ions influx. Results were statistically developed using the ANOVA and effect size (Cohen's d) analyses.

Results
In this study, the continuous exposure of adipose-derived stem cells to EMF (ICR parameters: 76.6 Hz; 20 μT) causes a statistically significant increase in cell death through the enhancement of apoptotic, necrotic, and autophagic cell numbers. Apart from increased cell deaths after EMF exposure, increased proliferation after 24 h of EMF exposure has been also observed.

Conclusions
Results presented in this study show that EMF influences stem cell dynamics resulting in a significantly increased cell death, thus altering the stem cell fate. It is important to further establish EMF conditions that support ASCs functioning and beneficial physiological processes for future regenerative medical purposes.
Determination of Multileaf Collimator Positional Errors as a Function of Dose Rate, Speed, and Delivery Interruption for Volumetric-Modulated Arc Therapy Delivery
Authors: Roy Soumya , Sarkar Biplab , Pradhan Anirudh 
Published: May 2024

Aim:
To determine the multileaf collimator positional error (MLC-PE) during volumetric modulated arc therapy (VMAT) delivery by studying the time-dependent MLC velocity in mathematically derivable trajectories such as straight line and conic sections.

Materials and Methods:
VMAT delivery is planned in a way that MLCs are moving in a locus which can be defined by mathematical functions such as linear, parabolic, or circular velocity (PV or CV). The VMAT delivery was interrupted either once or multiple times during the delivery and projection images of the same were acquired in electronic portal imaging device. MLC-PE was then analyzed as a function of dose rate (DR), and MLC speed (SP) and number of interruptions in treatment delivery. In VMAT delivery with linear MLC motion, the delivery was interrupted either once (linear motion single interruption) or multiple (three) times (linear motion multiple interruptions). For PV and CV MLC velocity, the MLC motions are interrupted multiple times.

Results:
The maximum individual error obtained (DR of 35 MU/min, SP of 2.0 cm/s) was 1.96 ± 0.1 mm. Only 4.4% of MLCs showed ≥ ±1 mm positional error. When the treatment delivery is interrupted multiple times in VMAT delivery, the influence of interruption in MLC-PE overwhelmed the influence by DR and SP. For a sub-group analysis of independent and dependent variables, the mean MLC-PE was 0.18 ± 0.4 mm 0.19 ± 0.42 mm, respectively.

Conclusion:
Determination of MLC-PEs using a mathematical function without approximation indicates that MLC-PE is not a function of MLC speed. In less than 5% of the studied scenarios, the MLC-PE exceeds its tolerance value (±1 mm). The MLC-PE is significantly less in modern machines due to advancements in the delivery mechanism.
Use of Multiple-Tube Phantom
Authors: Negi Pradeep Singh , Mehta Shashi Bhushan , Jena Amarnath 
Published: May 2024

Background:
Native T1 relaxation time (T10) presents an important prerequisite to reliably quantify pharmacokinetic parameter like Ktrans (volume transfer constant). Native T1 value can be varied because of the inhomogeneity in the breast coil, thus influencing the Ktrans measurement.

Purpose:
The current study aims to design and use a phantom with multiple tubes for both breast cuffs to assess native T1 inhomogeneity across the dedicated molecular magnetic resonance (mMR) breast coil and adopt corrective method to spatially normalize T1 values to improve homogeneity.

Materials and Methods:
Two phantoms with multiple tubes (19 tubes) specially designed and filled with contrast medium with known T1 value were placed in each mMR breast coil cuff. Native T1 at various spatial locations was calculated applying dual flip angle sequence. Correction factors were derived at various spatial locations as a function of deviation of the native T1 value from phantom and applied to correct the native T1 relaxation time.

Results:
A statistically significant difference between native T1 values of the right and left anterior (P = 0.0095), middle (P = 0.0081), and posterior (P = 0.0004) parts of the breast coil. No significant difference was seen in the corrected T1 values between anterior (P = 0.402), middle (P = 0.305), and posterior (P = 0.349) aspects of both sides of the breast coil.

Conclusion:
Inhomogeneity in the native T1 value exists in dedicated mMR breast coil, and significant improvement can be achieved using specially designed external phantom with multiple tubes.
An Investigation of Multileaf Collimator Performance Dependence on Gantry Angle Using Machine Log Files
Authors: Hughes Jeremy L. , Ebert Martin A. , McGarry Conor K. , Agnew Christina E. , Sabet Mahsheed , Rowshanfarzad Pejman 
Published: May 2024

Background:
Quality assurance of linear accelerators (linacs) is an important part of ensuring accurate radiotherapy treatment deliveries. The aim of this study is to investigate the role of gravity on the positional accuracy of multileaf collimator (MLC) leaves during complex radiotherapy treatments on linacs. This investigation is based on the analysis of the machine log files from five different linacs in multiple centers.

Materials and Methods:
Three main categories of deliveries were considered: Picket fence, volumetric modulated arc therapy (VMAT) (both delivering with continuous gantry rotation), and sliding gap tests delivered at cardinal gantry angles, to determine the error of the MLC in relation to the gantry angle.

Results:
Analysis of picket fence tests revealed a dependence of the error upon the gantry angle. For the majority of deliveries, the MLC showed greater error at gantry angles 270 and 90. The errors computed for the cardinal angles for sliding gap tests were all statistically different with greatest error arising at gantry angle 270 and least error at gantry 90. For picket fence, sliding gap, and VMAT cases, MLC errors were dependent on the gantry angle.

Conclusions:
The errors in leaf positioning were found to be dependent on the gantry angle. For sliding gap tests, the error was greater at gantry angle 270° and 90° and less when the leaf motion was perpendicular to the force of gravity.
Probability Distribution of Pixel Intensities of EBT3 Films and its Application in the Correction of Uncertainty Budget
Authors: Chaudhary Rahul Kumar , Pathan Munir , Kumar Rajesh , Sharma S. D. , Sapra B. K. 
Published: May 2024

Background and Aim:
Modern radiotherapy modalities, such as Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy involve complex dose delivery. The dose delivery is complex as it involves beam modulation, hence, manual dose calculations for these techniques are not possible. Film dosimetry is commonly used method of dose verification for these modalities because of the advantages associated with it. The quantification of uncertainty associated with a film dosimetry system under clinical use becomes important for accurate dosimetry. The spread in the distribution of the pixel values (PV) of the irradiated film contributes to the uncertainty. The probability distribution (PD) of the PV was studied for the clinical photon beam energies of 6, 10, and 15 MV.

Methods and Materials:
Gafchromic EBT3 film and EPSON 10000XL flatbed scanner were used for this purpose and using the resulting PD, the uncertainty budgets for these energies in the red, green and blue color channels were estimated.

Results:
The PV of exposed films for the energies studied follows t-distribution, the sum of the squares of the deviation of the measured data from the fitted value was of the order of 10−7, this indicates the goodness of fit. The “t” value corrected combined standard uncertainty (CSU) at 1σ confidence level for exposed film and dose measurement at 200 cGy were 1.42%, 1.48%, and 1.63% and 1.99%, 3.23%, and 5.08% for 6, 10, and 15 MV energies, respectively, in the red colour channel.

Conclusion:
In the case of the limited number of measurements of a quantity, the SU values must be corrected using the “t” value to get the correct CSU.
Comparison of Norepinephrine with Ephedrine Boluses for the Treatment of Maternal Hypotension during Cesarean Section Under Spinal Anesthesia: A Prospective Observational Study
Authors: Phogat Antima , Kavishvar Neeta 
Published: May 2024

Spinal Induced Hypotension:
Hypotension is one of the most common side effects of spinal anesthesia for lower segment cesarean section (LSCS). The most commonly used vasopressors for the treatment of spinal-induced hypotension (SIH) are phenylephrine, ephedrine, and norepinephrine.

Aim:
This study aimed to compare the efficacy of boluses of ephedrine and norepinephrine for the treatment of SIH in cesarean section.

Methods and Material:
A prospective observational study was conducted on 160 women undergoing elective and emergency cesarean section receiving spinal anesthesia with injection of bupivacaine heavily. Whenever hypotension (fall in systolic blood pressure (SBP) <20% from baseline value or SBP <80 mm Hg, whichever is less) occurred, either ephedrine (6 mg) or noradrenaline (6 μg) was given intravenous (IV) bolus as per the availability. Primary outcomes were maternal hemodynamic parameters, number of episodes of hypotension, requirement of bolus vasopressors, and Apgar score. Other outcomes were episodes of tachycardia, bradycardia, hypertension, and maternal side effects such as nausea, vomiting, shivering, and arrhythmia. Data analysis was performed with the help of Microsoft Excel and Statistical Package for the Social Sciences (SPSS) version 25. A P- value of <0.05 was considered statistically significant.

Results:
The mean SBP of both groups was comparable (P < 0.05). The mean heart rate (HR) was significantly higher in group E than in group N at 8 minutes and after till 60 minutes (P < 0.001). No statistical difference was found between the two groups in the Apgar score (P > 0.05). The mean dose requirement of ephedrine in group E was 1.94 and in group N was 2.04.

Conclusions:
Ephedrine (6 mg) and norepinephrine (6 μg) boluses are efficacious in treating hypotension after spinal anesthesia in obstetric patients. Norepinephrine appears to be favorable in view of HR than ephedrine.
To Study Maternal Hypotension, Side-Effects and Fetal Acid-Base Balance During Cesarean Delivery Under Spinal Anesthesia using Prophylactic Infusion Doses of 25 and 50 μg/Min Phenylephrine
Authors: Akshay R , Bajaj Jeetendra Kumar 
Published: May 2024

Objectives:
To study maternal hypotension, side effects, and fetal acid-base balance during cesarean delivery under spinal anesthesia using prophylactic infusion doses of 25 and 50 μg/min phenylephrine.

Methods:
This prospective randomized study was carried out at a tertiary care hospital on 100 pregnant women who underwent caesarean section under subarachnoid block. The participants were randomized into: Group P1 (n = 50): who received phenylephrine 25 μg/min infusion prophylactically and Group P2 (n = 50) received phenylephrine 50 μg/min infusion prophylactically. The two groups were compared for heart rate, blood pressure, side effects, and fetal arterial and venous blood gas analysis. P value < 0.05 was considered statistically significant.

Results:
In group P1, 3 (6%) patients had episode of hypotension and in group P2, 1 (2%) patient had episode of hypotension. There was no incidence of hypertension in group P1 but in group P2, 5 (10%) patients had hypertension (p < 0.05). There was no episode of bradycardia or oxygen desaturation in any group. Side effects were Grade 1 in three patients each in both the groups, and Grade 2 in one patient of Group P1 and four patients in Group P2 (p = 0.842). Fetal acid-base balance was comparable in the two groups (p > 0.05).

Conclusion:
It can be concluded that 50 μg/min phenylephrine was able to better prevent maternal hypotension with comparable side-effects profile and fetal acid base balance.
Non - Invasive Hemodynamic Parameters as Predictors for Hypotension following Spinal Anesthesia in Parturients Undergoing Lower Segment Cesarean Section: A Prospective Observational Study
Authors: Singhal Neelam , Bansal Amol , Duggal Rashmi 
Published: May 2024

Background:
In parturients undergoing lower segment cesarean section (LSCS) following spinal anesthesia hypotension is the most common side effect that may cause severe adverse effects in mothers such as nausea, vomiting, and dizziness. Very few studies have been done in the Indian population wherein multiple non-invasive hemodynamic parameters have been studied as predictors of hypotension following spinal anesthesia in parturients undergoing cesarean section. So we hypothesized that multiple non-invasive hemodynamic parameters like Perfusion Index (PI), Pleth Variability Index (PVI), and heart rate (HR) can predict hypotension following spinal anesthesia in parturients undergoing an elective cesarean section.

Methods:
We enrolled 40 parturients in this prospective observational study. Spinal anesthesia was performed with 10 mg of injection bupivacaine 0.5% (hyperbaric) at the L3–L4 or L2–L3 interspaces. Hypotension in parturient was defined as decrease in systolic blood pressure of greater than 20% from its baseline value. Baseline HR, PVI, and PI were recorded. Statistical analysis was performed using Unpaired t-test/Mann–Whitney test and Chi-Square test/Fisher’s exact tests. Area under the receiver operating characteristic (ROC) curve (AUC) was used to determine the sensitivity, specificity, and the cut-off value for the parameters.

Results:
Hypotension occurred in 57.5% of the parturients. It was observed that only PI could predict the development of post spinal hypotension in parturients undergoing LSCS (AUC = 0.835, 95% confidence interval [CI] 0.684–0.933, P = 0.001). The analysis of ROC curve was done and a new cut-off value of PI of >2.58 was found with 100% sensitivity and 70.6% specificity for predicting post-spinal hypotension, which was highly statistically significant, P value <0.001.

Conclusion:
The baseline PI is a useful predictor for hypotension in parturients undergoing spinal anesthesia. Other non-invasive hemodynamic parameters, that is baseline HR and PVI, however, could not anticipate hypotension in these parturients.
To Compare the Efficacy of Two Different Bolus Doses of Phenylephrine in Combination With Oxytocin in Preventing Oxytocin-Induced Hypotension during Cesarean Section Under Spinal Anesthesia: A Randomized Comparative Study
Authors: Kumari Snehalata , Barman Ratindra K. , Kalita Pranab , Engti Peter 
Published: May 2024

Background:
A randomized comparative study was conducted to assess the effectiveness of two different bolus doses of phenylephrine to obtund the hypotensive effects of bolus oxytocin injection in patients undergoing cesarean section under spinal anesthesia.

Methods:
The study involved 180 parturients belonging to the ASAI and II, undergoing CS under SA were randomized into three groups, group A: oxytocin 3U and phenylephrine 50 μg; group B: oxytocin 3U and phenylephrine 75 μg; group C: oxytocin 3U and normal saline, administered intravenously over 5 min after delivery of anterior shoulder. The incidence of hypotension being the primary objective and hemodynamic changes, the incidence of nausea and vomiting, and other complications, such as total rescue vasopressor requirement, adequacy of uterine contraction, and the number of patients requiring additional uterotonics, were our secondary objectives.

Results:
The incidence of hypotension was highest in group C (83.3%) followed by group A (80%) and lowest in group B (11.6%). The total rescue doses of PE after T0 between the three groups showed that group A required (61.32 ± 41.19) μg, group B required (10.19 ± 29.75) μg, and group C required (113.21 ± 47.18) μg of PE. The uterine contraction was comparable between the groups. Incidence of nausea and vomiting and other complications were comparable between the groups.

Conclusion:
Co-administration of PE 75 mg with OT 3 IU after delivery reduces the incidence of OT-induced hypotension and rescue vasopressor requirement compared to co-administration of 50 μg PE during CS under spinal anesthesia.
Evaluation of Perfusion Index as a Screening Tool for Prediction of Hypotension and Shivering in Cesarean Section
Authors: Gandhi Parita , Kheskani Divya , Chhanwal Heena Sunil , Solanki Rekha Nilesh , Shah Meet , Singh Aayushi 
Published: May 2024

Aim:
The aim of this study was to determine whether a baseline perfusion index (PI) can predict hypotension and shivering after spinal anesthesia for cesarean section.

Materials and Methods:
In this prospective, observational study, 100 parturients were divided into two groups on the basis of baseline PI. Group I included parturients with PI of <3.5, and Group II included parturients with PI values ≥3.5. Spinal anesthesia was performed with hyperbaric 2 ml of 0.75% ropivacaine at L3–L4 or L2–L3 interspace. Hypotension was defined as mean arterial pressure <65 mmHg. PI and blood pressure were monitored at baseline, every 2 min for 12 min, and every 10 min until 120 min. Shivering was observed until 120 min according to the Crossley and Mahajan scale. Statistical analysis was performed using Chi-square test, independent sample t-test, and Mann–Whitney U-test.

Results:
Baseline PI significantly correlated with the number of episodes of hypotension. The overall incidence of hypotension was significantly higher in parturients with baseline PI ≥3.5 (79.16%) compared to those with PI <3.5 (33.33%), and parturients with preoperative PI <3.5 had a greater risk of post-anesthetic shivering.

Conclusions:
Perfusion Index serves as an excellent tool for predicting hypotension and shivering in pregnant patients.
Head Fixation in Head Frame in Surgeries of Unstable Craniovertebral Junction through Midline Posterior Approach
Authors: Jha Deepak Kumar , Jha Ashutosh , Garg Mayank , Gosal Jaskaran Singh , Agrawal Mohit , Sharma Raghavendra Kumar , Khera Pushpinder Singh 
Published: May 2024

Abstract
Intraoperative skeletal traction with Gardner-Wells tongs or Crutchfield tongs is often used during surgery for craniovertebral junction (CVJ) instability. During these posterior surgical procedures for CVJ instability, there is pressure on occiput/C1 while subperiosteal dissection, drilling, and insertion of screws. With cervical traction, there is a possibility of anterior movement of occiput/C1 due to pressure while performing the above steps. This may lead to undesirable compression of the cervicomedullary junction. The use of rigid head fixation during CVJ surgeries will prevent any such unwanted anterior movement of occiput/C1. Furthermore, the use of the reverse Trendelenburg position allows the body weight to provide counter traction while the rigid frame provides traction allowing reduction of atlantoaxial dislocation. Authors conclude that head fixation in the frame is safer than skeletal traction for CVJ surgeries, through midline posterior approach, for traumatic or congenital anomalies related instabilities.
Posterior Spinal Screw Fixation Techniques and Trajectories: General Overview and an Analysis of How Often They Are Used
Authors: Andermatten Joaquin , Chaurasia Bipin , Lopo Anne Fernandez , Puertas Garazi Marticorena , Samprón Nicolás 
Published: May 2024

Abstract

Background:
There is a great variety of techniques (translaminar, transfacet, and extrapedicular screws) apart from the traditional pedicle screw in posterior spinal instrumentation. The latter technique is the most widely used around the world (except from the cervical region) since it tends to obtain very good results with a simple approach with fewer complications.Therefore, other trajectories are usually reserved for more specific cases in which the insertion of these purely pedicle screws is not possible.

Objective:
The objective of this study was to review and analyze the use of different techniques and trajectories of posterior spinal instrumentation by different spinal surgeons around the world.

Material and Methods:
We developed a survey including posterior spinal screw techniques and trajectories. In this article, we present the data resulting from 122 answers from different spinal surgeons (neuro, orthopedic surgery).

Results:
Despite advances in the development of new technologies such as neuronavigation (17%) and robotic (1%) available on the market, nowadays, the gold-standard technique for spinal screw insertion is the fluoroscopy-assisted freehand approach (54%). The lumbar spine is the most instrumented spinal region (31%), with a clear preference for purely transpedicular screws. Thoracic and sacroiliac areas presented a greater diversity of screw trajectories. In the cervical spine, there is a clear tendency toward the insertion of lateral mass screws (85% in the atlantoaxial region and 70% in the subaxial region), as opposed to the use of pedicular screws. This is mainly due to the complexity of this area and the risk of damaging important neurovascular structures relatively close to the pedicles. Unexpectedly, two additional techniques were presented: cortical bone trajectory for lumbar screw fixation (for osteoporotic patients) and S2-alar-iliac screw fixation (more used than iliac screws alone).

Conclusions:
This survey demonstrates that the most used spinal trajectory in the thoracolumbar spinal region is the traditional pedicle screw insertion. Lateral mass was the most common place to insert screws in the subaxial cervical region. The use of robotic systems can improve the position of the screws of more complex techniques. We consider that the different techniques should be known since every surgery will be adapted to the patient’s anatomy and needs.
Comparative study on the extraction strength of solvents on tar sand from Okitipupa, Ondo State
Authors: Akpan U.G. , David Z. , Emena A. 
Published: May 2024

Tar sand, an aggregate of sand, clay, water and bitumen was sampled from Okitipupa area of Ondo State, Nigeria, extracted and optimized using n-hexane and toluene in a soxhlet extractor todetermine solvent effectiveness in extracting the bitumen content and their environmental effect. The experiment was carried out by heating the solvent at and above their boiling temperatures solely to get an optimum yield at a temperature and time of extraction of oil from the tar sand. The analysis gave an optimal yield of 9.07 % at 75oC in 4 h when n-hexane was used and an optimal yield of 21.27 % at 120oC in 4 h when toluene was used. A drastic change in colour was also notice in the sand residue to almost sandy soil nature when toluene was used as solvent compare to when n-hexane was used which shows a slight change from its blackish nature. The change in colour of the black tar sand is an indication of high extraction efficiency. Hence, owing to high demand for conventional oil supply in the country and the urgent need for an alternative source of oil, the bitumen extract can serve as an alternative source of unconventionaloil supply in Nigeria and feedstock in refineries.