Pre-exponential Factor Research Articles

Feline blood donation: Description and adverse reactions from 29 201 donation events between 2019 and 2023.

Feline blood transfusion is required for the treatment of various illnesses in cats, and the safety of donor cats is vital. Donor adverse reactions can include cardiorespiratory, venepuncture-related, and behavioral abnormalities. To describe a large number of feline blood donation events and document use of sedation and anxiolysis, record volume of blood collected and describe the frequency, type, and risk factors for, adverse reactions. The study included 7812 individual cats and 29 201 donation events at a blood banking center over 5 years. Retrospective analysis of donation event records with signalment, donation volume, sedation status, donation number, and adverse reactions (acute and caregiver reported) recorded. Risk factors for adverse reactions were examined by stratifying data according to groups exposed to relevant predictors and calculating odds ratios with 95% and 99% confidence intervals (CIs). Adverse reactions were uncommon (0.29%, 2.88/1000 donor events) and most commonly were cardiorespiratory (0.08%, 0.75/1000 donor events) or behavioral (0.06%, 0.62/1000 donor events). The only risk factor significantly associated with adverse reactions was conscious donation, with conscious donors 4.4 times more likely to have an adverse reaction (95% CI, 2.5-7.9, P ≤ .0001). Feline blood donation is associated with a low rate of adverse reactions. Sedation should be considered to reduce adverse reactions, and the environment and interactions optimized to reduce donor stress. Caregiver education on care postdonation could reduce behavioral adverse reactions.

Theoretical Investigation into Polymorphic Transformation between β-HMX and δ-HMX by Finite Temperature String

Polymorphic transformation is important in chemical industries, in particular, in those involving explosive molecular crystals. However, due to simulating challenges in the rare event method and collective variables, understanding the transformation mechanism of molecular crystals with a complex structure at the molecular level is poor. In this work, with the constructed order parameters (OPs) and K-means clustering algorithm, the potential of mean force (PMF) along the minimum free-energy path connecting β-HMX and δ-HMX was calculated by the finite temperature string method in the collective variables (SMCV), the free-energy profile and nucleation kinetics were obtained by Markovian milestoning with Voronoi tessellations, and the temperature effect on nucleation was also clarified. The barriers of transformation were affected by the finite-size effects. The configuration with the lower potential barrier in the PMF corresponded to the critical nucleus. The time and free-energy barrier of the polymorphic transformation were reduced as the temperature increased, which was explained by the pre-exponential factor and nucleation rate. Thus, the polymorphic transformation of HMX could be controlled by the temperatures, as is consistent with previous experimental results. Finally, the HMX polymorph dependency of the impact sensitivity was discussed. This work provides an effective way to reveal the polymorphic transformation of the molecular crystal with a cyclic molecular structure, and further to prepare the desired explosive by controlling the transformation temperature.

Dy3+ doped Zn0.66Mg0.3Al2O4 nanophosphor for high dose radiation thermoluminescence dosimetric applications

Zinc Magnesium Aluminate doped with Dysprosium (Zn (1-x-y) Mg(y)Al2O4:x Dy (x=0.04 and y=0.3 mol%)) was prepared using the solution combustion synthesis method. The prepared phosphor was characterized using energy-dispersive X-ray spectroscopy, scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and Fourier transform infrared, respectively, to study crystal structure, surface morphology, and vibrational properties. The thermoluminescence peak temperatures were 250°C, 248°C, and 246°C at irradiating doses of 600–1000 Gy, respectively. Through the computation of the activation energy (E), order of kinetics (b), and frequency factor (s−1), the kinetic parameters were assessed using the TL glow curve. It is observed from the TL dose-response curve that the intensity rises nearly linearly for all doses between 600 and 1000 Gy. Nanophosphor Zn0.66Mg0.3Al2O4:0.04Dy shows almost linear dose-response for a dose range of 600–1000 Gy and an optimum activation energy (E) of 0.93–0.97 eV, which makes it suitable for high-dose radiation thermoluminescence dosimetric applications.

Evaluation of akathisia in patients receiving selective serotonin reuptake inhibitors/serotonin and noradrenaline reuptake inhibitors.

Akathisia is an underestimated but disturbing extrapyramidal side effect of antidepressants, which could reduce treatment compliance in mood disorders. This study aimed to investigate the frequency and risk factors in patients treated with selective serotonin reuptake inhibitors/serotonin and noradrenaline reuptake inhibitors (SSRI/SNRI). In addition, we assessed the impact of akathisia on the quality of life (QoL). Patients were aged between 18 and 75 years, receiving an SSRI/SNRI for 4-8 weeks, and were diagnosed with anxiety, depression, or obsessive-compulsive disorder. The Barnes Akathisia Rating Scale was used to assess the severity of the akathisia. QoL was evaluated using the Short Form 36 (SF-36) questionnaire. Akathisia was observed in 25% (50/198) of patients. Smokers and younger patients were more frequent among patients with akathisia. Physical functioning, physical role, vitality, and mental health domains of the SF-36 were reduced in the presence of akathisia. In conclusion, our results suggest that akathisia is not a rare side effect of SSRI/SNRI in patients with mood disorders, especially in smokers and younger patients. In addition, akathisia may reduce treatment compliance owing to a reduction in QoL. Further investigations are needed to confirm the risk factors, frequency, and consequences of treatment compliance for SSRI/SNRI-induced akathisia in patients with mood disorders.

Kinetics study of pyrolysis of petroleum sludge and characterization of char

Thermochemical conversion (or pyrolysis) has emerged as an effective technique for the disposal of sludge generated in process industries. This paper reports physicochemical characterization and kinetic analysis of pyrolysis of sludge from a petroleum refinery and characterization of resultant char. The sludge had high volatile matter (>70 wt%) and low ash content (15 wt%). Pyrolysis of sludge was studied using a thermo-gravimetric analyzer (TGA). The TGA data was analyzed using two isoconversional models, viz. KAS and Vyazovkin AIC are used for the deduction of kinetic triplets, viz. activation energy, pre-exponential factor, and reaction mechanism. The activation energy (Ea ) of sludge pyrolysis varied in the 64.79–190.37 kJ/mol range. The pre-exponential factor varied from 1.18E + 07 to 4.29E + 12 s−1. The predominant solid-state mechanism of thermal conversion was an order-based reaction (F2/F3). The thermodynamic factors (viz. ΔH, ΔS, ΔG) of sludge pyrolysis were also determined. Relatively small values of (Ea – ΔH) ∼ 5 kJ/mol revealed high susceptibility of sludge for thermal conversion. Residual char after pyrolysis was characterized for physicochemical properties. The char properties were fixed carbon = 54.37%, calorific value = 22.48 MJ/kg, and BET surface area = 18.35 m2/g. These properties make char suitable for numerous applications.

Assessment of the frequency and risk factors of gastrointestinal bleeding after cardiopulmonary bypass in paediatric cases.

Gastrointestinal bleeding is a potential complication in paediatric patients undergoing cardiopulmonary bypass, as it develops secondary to low gastrointestinal perfusion. This study aimed to examine the incidence of gastrointestinal bleeding and identify its risk factors in these patients. This retrospective study was undertaken to examine the demographic features, clinical findings, and operative data of paediatric patients under years old who had undergone congenital heart surgery with cardiopulmonary bypass between November 1, 2021, and November 1, 2023. The study aimed to investigate the incidence of gastrointestinal bleeding associated with cardiopulmonary bypass and to identify potential risk factors for gastrointestinal bleeding. The obtained results were statistically evaluated. The study period included 1100 patients who underwent congenital heart surgery with cardiopulmonary bypass. Fifty-two percent of the total participants were male. The median weight of the patients was 4.4 kg, with an interquartile range of 3.5-5.8 kg. The patients were categorised by age, revealing that 62% were newborns, 24% were infants, and 14% were children. Forty-four (4.2%) of the total number of patients experienced gastrointestinal bleeding. Newborns had a significantly higher incidence of bleeding (6% or 34 patients) compared to infants (3% or 8 patients) and children (1.5% or 2 patients) (p < 0.05). Patients who experienced gastrointestinal bleeding had a longer median hospital stay of 24 days compared to those who did not, with a median hospital stay of 14 days. Moreover, patients who suffered from bleeding had a significantly higher mortality rate (30%) in comparison to those who did not (9.9%) (p < 0.05). The incidence of gastrointestinal bleeding was found to be associated with several risk factors, such as low operative age and weight, high surgical score, presence of low cardiac output syndrome, extracorporeal membrane oxygenation (ECMO) usage, high lactate levels, and low platelet count. Gastrointestinal bleeding is a potential complication for patients who undergo cardiopulmonary bypass. It is particularly relevant for newborns who have undergone prolonged surgery, have a high surgical complexity score, exhibit high lactate levels, display low cardiac output, utilise ECMO, and possess low platelet counts. In such cases, there may be a heightened incidence of gastrointestinal bleeding. It is important to consider this possibility in order to ensure the best possible patient outcomes.

Thromboembolism during immune checkpoint inhibitor therapy: frequency and risk factors

BackgroundThromboembolism (TE) is a well-known complication during chemotherapy in cancer patients. However, the risk of TE associated with immune checkpoint inhibitors (ICIs) is unknown. This study was performed to investigate the incidence of TE and associated risk factors in patients treated with ICIs.MethodsWe conducted a retrospective chart survey of patients receiving at least one ICI at Shinshu University Hospital between September 2014 and October 2021. Age, sex, cancer type, body mass index, medical history, laboratory data at commencement of treatment, and medication data were obtained from electronic medical records. TE events (venous thromboembolism [VTE], arterial thromboembolism [ATE]) were identified after ICI initiation.ResultsThe study population consisted of 548 patients with a median age of 70.0 (19–89) years, 71.4% men, and a median follow-up of 15.1 months (range; 0.16–72.0 months). Nivolumab was the most commonly used ICI (45.8%), followed by pembrolizumab (23.9%), pembrolizumab plus anticancer drugs (7.8%), and nivolumab plus ipilimumab (5.1%). Thirty-eight cases of TE (6.9%) occurred (22 VTE, 16 ATE). Risk factors significantly associated with TE in multivariate logistic analysis were dyslipidemia (OR 2.44; 95% CI 1.17–5.09; p = 0.017), Khorana score ≥ 2 (HR 2.40; 95% CI 1.14–5.04; p = 0.021). Overall survival was not significantly different from patients without TE (p = 0.963).ConclusionThese results suggested that the frequency of TE is higher than expected and should be considered and monitored in patients treated with ICIs.

Kinetic and thermodynamic analysis of the PET-date seed mixture co-pyrolysis using Coats-Redfern method

This study focuses on improving the polyethylene terephthalate (PET) pyrolysis outcome by incorporating date pits in a balanced 50–50 mixture. The effect of date pit addition on the co-pyrolytic process is determined via thermal analysis using the Coats-Redfern method, which provides an estimation of the activation energy and the pre-exponential factor of the PET-Date mixture. The results demonstrate that the majority of the reaction mechanisms exhibit enhanced performance for the modified mixture, requiring 70 % less reaction energy on average. Hence, a positive effect is observed on the PET pyrolysis, thus highlighting its potential for biomass incorporation. This study provides valuable insights into optimising the co-pyrolytic processes for sustainable waste management and resource utilization practices.

Investigation of halloysite thermal decomposition through differential thermal analysis (DTA): Mechanism and kinetics assessment

The study focused on analysing the kinetics of halloysite decomposition using the differential thermal analysis (DTA) technique. Tests were carried out across a temperature span from ambient temperature to 1673 K, employing heating rates spanning from 5 to 20 °C.min−1. X-ray diffraction and Fourier transform infrared spectroscopy (FT-IR) were utilized to identify the phases formed at different temperatures. Activation energies for halloysite decomposition were determined through isothermal and non-isothermal treatments, yielding values of approximately 151.68 kJ mol−1 and 173.14 kJ mol−1, respectively. The Ligero method's Avrami constant parameter (n) and the Matusita method's numerical factor parameter (m), linked to crystal growth dimensions, were both around 1.5. These findings indicate that the degradation of halloysite is primarily governed by bulk nucleation, succeeded by the 3-dimensional growth of meta-halloysite characterized by polyhedron-like structure, regulated by diffusion from a consistent number of nuclei. The frequency factor for halloysite dehydroxylation was established at 8.48 × 10⁸ s⁻1.

Analysis of the perceived intensity of vibratory stimuli driven by the Modal Overlap Factor

The vibro-tactile perception experiment reported in this paper aims to investigate correlations between the perceived vibratory intensity and the Modal Overlap Factor (MOF) of vibratory stimuli. The MOF is often used to physically characterise the vibratory behavior of a structure and can be estimated from the product of frequency, modal density and modal loss factor. In this experiment, stimuli are applied to the participant's hands by means of a steering wheel set in vibration by a shaker. The vibratory stimuli are synthesized from filtered white noise convolved with an impulse response defined as a sum of damped sine waves. The MOF can be controlled by selecting the number of sine waves, their frequency and damping ratio. A set of 100 stimuli, with MOF values ranging from 2 to 200%, in the 5-305Hz range, and equalized in acceleration, is used. Each of the 80 participants is asked to rate twice the perceived intensity of 10 stimuli, pseudo-randomly chosen among the 100 stimuli. Data are analyzed to establish trends between perceived vibratory intensity and the physical parameters of the stimuli.

Temperature-Dependent Oxidation Behavior of Silicon Carbide Surface: Reactive Molecular Dynamics Simulations.

The high-temperature oxidation mechanism of silicon carbide (SiC) is crucial for designing thermal protection systems in aircraft. This study explored the oxidative chemical reaction processes and mechanism on SiC surface and interfaces within the temperature range of 300-2300 K by using reactive molecular dynamics simulation. The oxygen impact on the silica (SiOx) growth of the SiC surface was analyzed, which shows a progressive increase of silica thickness. The simulation results indicated that the oxidation process of SiC was a typical passive oxidation mechanism. With the environmental temperature rising and oxygen impact, the increase of oxidation thickness on the SiC surface undergoes three oxidizing reaction processes: little chemical adsorption of oxygen molecules on the initial surface, rapid oxidation of silicon and carbon, and dramatic oxidation of the interface between the oxidation layer and SiC. Additionally, this work studied the mechanism of oxidation thickness growth and chemical diffusion of oxygen. The oxidation rate is weakened according to the oxygen atom diffusion barrier effect of silica repulsion. Moreover, the kinetic parameters were statistically calculated by fitting the growth of Si-O bonds and their reaction rate constants. Subsequently, the activation energy and pre-exponential factors were derived by using the Arrhenius equation to model the chemical reaction kinetics of the thermal oxidation process. The chemical reaction behaviors of the two stages could be concluded as follows: (i) in stage I, the initial oxidation is reaction rate limiting; (ii) in stage II, SiC oxidation is limited by both the oxidation reaction rate and the oxygen diffusion coefficient of the oxidation layer. The activation energy of stage II increased compared with stage I due to the oxygen atoms diffusion barrier between the oxidation layers. This study on the oxidation and ablation mechanism of the SiC surface at the atomic scale would provide insight into understanding thermal oxidation behavior and the design of ceramic materials.

Kinetic model of thermal decomposition of nitric acid solutions of hydrazine nitrate

The kinetic parameters of thermal decomposition of an aqueous solution containing 0.029 mass fractions of hydrazine nitrate and 0.44 mass fractions of nitric acid have been determined: onset temperature and specific thermal effect of exothermic reactions, activation energy, pre-exponential factor, reaction rate and order. Based on the data obtained, a mathematical model of thermal decomposition of nitric acid solutions of hydrazine nitrate has been proposed. It has been found that thermolysis of the solution has a multi-stage nature and can be described by a system of 5 equations of 1st and 2nd order. A comparison of two approaches to creating a mathematical model has been carried out: based on adiabatic calorimetry and differential scanning calorimetry data.

Thermoluminescence and Apollo 17 ANGSA Lunar Samples: NASA's Fifty‐Year Experiment and Prospecting for Cold Traps

AbstractBy placing Apollo 17 regolith samples in a freezer, and storing an equivalent set at room temperature, NASA effectively performed a 50‐year experiment in the kinetics of natural thermoluminescence (TL) of the lunar regolith. We have performed a detailed analysis of the TL characteristics of four regolith samples: a sunlit sample near the landing site (70180), a sample 3 m deep near the landing site (70001), a sample partially shaded by a boulder (72320), and a sample completely shaded by a boulder (76240). We find evidence for a total of eight discrete TL peaks, five apparent in curves for samples in the natural state and seven in samples irradiated in the laboratory at room temperature. For each peak, we suggest values for peak temperatures and the kinetic parameters E (activation energy, i.e. “trap depth,” eV) and s (Arrhenius factor, s−1). The lowest natural TL peak in the continuously shaded sample 76240 dropped in intensity by 60 ± 10% (1976 vs. present room temperature samples) and 43 ± 8% (freezer vs. room temperature samples) over the 50‐year storage period, while sunlit and partially shaded samples (70001, 70180, 72321, 72320) showed no change. These results are consistent with the E and s parameters we determined. The large number of peaks, and the appearance of additional peaks after irradiation at room temperature, and literature data, suggest that glow curve peaks are present in lunar regolith at ∼100 K and their intensity can be used to determine temperature and storage time. Thus, a TL instrument on the Moon could be used to prospect for micro‐cold traps capable of the storage of water and other volatiles.

Preliminary study of coda wave attenuation around Yogyakarta based on Meramex temporary stations data

Abstract The tail of a seismogram record, the coda, usually comes from the high-order scattered waves from some heterogeneities in the earth’s crust. Coda waves can be used to estimate the earthquake attenuation, site amplification and to determine the magnitudes. This preliminary study investigates the seismic attenuation property around the Yogyakarta region, Indonesia, from the Meramex temporary network. The Meramex network was installed from May to October 2004. We estimated the coda wave attenuation using the back-scattering model. We presented results from two station measurements (AJ1 and AI1) in this preliminary study. We analyzed shallow earthquakes (&lt;40km) with distances less than 3 degrees. We bandpass filter the data with central frequencies of 1, 2, 4, 6, 8, 10, 12, and 14 Hz. The coda window begins from twice the S-wave arrival time with a window length between 20 and 80 seconds. We estimated the coda quality factor (Qc) for each central frequency. The Qc at reference frequency 1 Hz yields the estimation for Q0 and the frequency-dependent factor (η) of 64 - 134 and 1.14-0.95, respectively. The Q0 value increased significantly in the window length of 20 to 30 seconds and was relatively stable in the window length of 30 seconds, but the η value is the contrary. The rise of the Q0 and decrease of η is apparently due to the heterogeneity of the earth’s crust, and the flat may be associated with the uniformity of the upper mantle.

Frequency and risk factors of congestive heart failure in hemodialysis patients in Assiut University Hospital

Background Cardiac failure is a leading cause of death for patients with chronic kidney disease and end-stage renal disease (ESRD). This study aimed to assess the prevalence of congestive heart failure (HF) in ESRD patients and evaluate its main risk factors. This data will help to provide better care to our patients and improve the outcome. Patients and methods A descriptive observational study was carried out on 290 individuals with ESRD who were on regular hemodialysis. The patients were categorized into two groups based on cardiac failure. The first group consisted of individuals diagnosed with HF, whereas the second group included people who showed no signs of HF. Results Logistic regression analysis revealed that smoking, hemoglobin level, ultrafiltration rate, ischemic heart disease, and ejection fraction were considered independent predictors for HF ESRD patients. Conclusion Congestive HF is prevalent among people undergoing hemodialysis. The main reasons for this high occurrence included the high prevalence of cardiovascular risk factors such as diabetes and hypertension, along with complications of renal failure such as anemia.

Frequency and risk factors for Mucormycosis, A Multicenter experience

Frequency and risk factors for Mucormycosis, A Multicenter experience

Risk factors and evolution of weight loss in Parkinson’s disease: a 9-year population-based study

Introduction:Weight loss is considered a common complication of Parkinson`s disease (PD), but there are few prospective longitudinal studies on weight loss in patients followed from time of PD diagnosis. We sought to determine the frequency, evolution and risk factors of weight loss in a representative incident PD cohort. Methods: In this prospective population-based observational study, we followed 180 newly-diagnosed, initially drug-naïve PD patients and 161 controls with repetitive weight examinations over 9 years. We used Cox regression models with adjustment for potential confounders to identify independent risk factors of clinically significant (>10%) weight loss. Results: Mean % weight change during follow-up was -3.9 (±11.2) in patients and -1.4 (±8.1) in controls (p=0.016). Clinically significant weight loss was observed in 26.7% of patients and 10.6% of controls (RR 2.53; 95% CI 1.52-4.21; p<0.001). Age was the only independent baseline risk factor for weight loss (HR 1.06 per year; 95% CI 1.03-1.10; p<0.001). Additional time-dependent risk factors were presence of olfactory impairment (HR 2.42; 95% CI 1.14-5.15; p=0.021), presence of dyskinesias (HR 3.14; 95% CI 1.58-6.23; p=0.001), and cognitive impairment (HR per MMSE unit 0.90; 95% CI 0.82-0.99; p=0.036). Dopamine agonist use reduced the risk of weight loss during follow-up (HR 0.44; 95% CI 0.24-0.82; p=0.007) Conclusion: The risk of weight loss is more than doubled in the general PD population and associated with both disease-related features and drug-related complications. This suggests a multifactorial nature of weight loss in PD, which is important to consider in research and clinical practice.

Insulin therapy use in gestational diabetes: Frequency and predictive factors

Insulin therapy use in gestational diabetes: Frequency and predictive factors

Development of nanocrystallized magnetoelastic sensors with self-biased effect and improved mass sensitivity

The growing demand for cost-effective and wireless sensing technologies requires the development of simple, efficient and optimized sensors able to accurately detecting external agents. Magnetoelastic resonators represent an alternative to the traditional sensing systems, able to combine all the previously cited factors. Several studies have focused on increasing their sensitivity, in order to make it closer to the market. The present study explores thermal treatments as a novel approach to enhance the sensitivity of magnetoelastic resonators, focusing on the positive impact of crystallization processes induced in magnetoelastic platforms. The experimental results confirm an enhancement of resonant frequency and quality factor of the magnetoelastic platforms as treatment temperature increases. Particularly, the sensor annealed at 550 °C shows an increase of the resonant frequency value of 45 % with respect to the as-quenched platform, being that increase of around 1700 % for the quality factor. In addition, the nanocrystallization induction leads to a self-biased resonance, consequence of the intrinsic magnetization resulting from the crystallization in Fe2B and FeCo phases. Further, the study shows the importance of stability in resonant frequency, emphasizing the potential of the 550 °C-annealed platform for mass sensor applications. Gold deposition experiments reveal the enhanced sensitivity of the sensor annealed at 550 °C of 40 % compared to the as-quenched sensor, as well as an increase of 38 % on its accuracy. These findings represent a significant step forward in the development of magnetoelastic-based mass sensors, highlighting the pivotal role of thermal treatments in optimizing sensitivity for practical and efficient external agents detection systems.

Characterization of Monosubstituted Benzene Ices

Aromatic structures are fundamental for key biological molecules such as RNA and metabolites and the abundances of aromatic molecules on young planets are therefore of high interest. Recent detections of benzonitrile and other aromatic compounds in interstellar clouds and comets have revealed a rich aromatic astrochemistry. In the cold phases of star and planet formation, most of these aromatic molecules are likely to reside in icy grain mantles, where they could be observed through IR spectroscopy. We present laboratory IR spectra of benzene and four monosubstituted benzene molecules—toluene, phenol, benzonitrile, and benzaldehyde—to determine their IR ice absorbances in undiluted aromatic ices, and in mixtures with water and CO. We also characterize the aromatic ice desorption rates, and extract binding energies and respective pre-exponential factors using temperature-programmed desorption experiments. We use these to predict at which protostellar and protoplanetary disk temperatures these molecules sublimate into the gas phase. We find that benzene and monosubstituted benzene derivatives are low-volatility with binding energies in the 5220–8390 K (43–70 kJ mol−1) range, which suggests that most of the chemistry of benzene and of functionalized aromatic molecules is to be expected to occur in the ice phase during star and planet formation.