Pre-exponential Factor Research Articles

Misinterpretation of Thermodynamic Parameters Evaluated from Activation Energy and Preexponential Factor Determined in Thermal Analysis Experiments

Thermogravimetry (TGA) and differential scanning calorimetry (DSC) are used broadly to study the kinetics of thermally stimulated processes such as thermal decomposition (pyrolysis) or thermal polymerization. These studies typically yield the activation energy (E) and preexponential factor (A). The resulting experimental values of E and A are oftentimes used to determine the so-called “thermodynamic parameters”, i.e., the enthalpy, entropy, and Gibbs free energy. Attention is called to the persistent and mistaken trend to interpret the resulting quantities as the thermodynamic parameters of the conversion of reactants to products. In fact, these quantities are specific to the conversion of reactants to the activated complex and, as such, provide no insights into the thermodynamics of the conversion of reactants to products. The basics of the activated complex (transition state) theory are provided to explain the meaning of the equations used for evaluating the thermodynamic parameters from the experimental values of E and A. Typical examples of misinterpretation are highlighted and discussed briefly. The applicability of the theory to the systems studied by the thermal analysis kinetics is also discussed.

Co-Pyrolysis of Mushroom Residue Blended with Pine Sawdust/Wheat Straw for Sustainable Utilization of Biomass Wastes: Thermal Characteristics, Kinetic/Thermodynamic Analysis, and Structure Evolution of Co-Pyrolytic Char

Co-pyrolysis technology is considered to be one of the most promising methods for the sustainable utilization of biomass wastes, as it can realize waste reduction and convert wastes into high-value-added products with little impact on the environment. The evaluation of thermal characteristics and product properties is necessary for understanding this technique. In this paper, thermal characteristics and kinetic and thermodynamic analysis during the co-pyrolysis of mushroom residue (MR) with pine sawdust (PS) or wheat straw (WS) were investigated in a TGA. The carbon structure and surface textures of co-pyrolytic char were explored using Raman spectroscopy and a scanning electron microscope. As the PS or WS mass ratio increased, the devolatilization index increased obviously, indicating that volatile release was promoted and concentrated. Weak interactions were observed between 250 and 400 °C during the co-pyrolysis process, which primarily affected the mass transfer, resulting in a change in the thermal decomposition temperatures and rates. The interactions had no prominent influence on the volatiles’ yields. The non-additive performance of average activation energies for the blends was observed due to the interactions, and the lowest average activation energy was obtained when the PS or WS mass ratio was 50%. The lower average pre-exponential factor of the blends indicated the reduced complicacy of the pyrolysis reaction. The relatively small deviation between the activation energy and enthalpy change (4.94–5.18 kJ·mol−1) signified the energy sensitivity of product formation. PS promoted the formation of small aromatic rings (<6 fused rings) in co-pyrolytic chars, whereas WS favored the production of larger rings (≥6 fused rings). The surface textures of the co-pyrolytic chars became porous, and the greater fractal dimensions of the surface morphology for the co-pyrolytic chars indicated that the char surface became irregular and rough.

Rapid pyrolysis technique for determination of kinetic parameters of ammonium perchlorate decomposition

A laser pyrolyser setup is developed to achieve isothermal conditions using a heating rate of up to ∼105 °C.s−1 for rapid pyrolysis of a sample. It provides mechanistic information about the decomposition behavior of the sample during combustion, typically in the condensed phase. Typically, chemical kinetics data for condensed phase reactions during combustion is not derived from ab initio techniques, but rather by fitting the variation of linear burning rate with pressure with appropriate kinetic parameters. This leads to a wide variation of chemical kinetic parameters governing the decomposition of the same solid propellant ingredient, such as the commonly used oxidizer, ammonium perchlorate (AP). Therefore, a newly developed laser pyrolyser along with Fourier transform infrared (FTIR) spectroscopy was used to study the rapid pyrolysis of AP at 1 bar. The concentration profiles of the evolved gases were used to develop the global reaction mechanism. The global reaction mechanism that emerged is: NH4ClO4→1.09H2O+0.06HNO3+0.56NO2+0.18N2O+0.5Cl2+0.71O2+0.88H2 with pre-exponential factor (A) = 6.6×107 s−1 and activation energy (Ea) = 108 kJ.mol−1. Kinetic parameters of the same AP sample from thermogravimetric analysis are A = 5.6 ×105 s−1, and Ea = 100 kJ.mol−1. This suggests that kinetic parameters obtained from slow heating experiments predict a reaction rate significantly lower than that observed under high heating rates. Therefore, the raw data generated from rapid pyrolysis would be useful as an input to solid propellant combustion models improving their predictive capability.

Exploring the associations between chronotype, meal frequency, and physical activity: A population-based study in adults

ABSTRACT Chronotype is an established concept designed to capture the internal clock’s phase in real-life conditions. It is vital in many aspects of daily life and can interfere considerably with numerous factors in a given population. Recognizing nonmodifiable and modifiable factors is crucial for identifying covariates of interest when studying the link between chronotype and health status. To date, chronotype and its related factors have not been extensively investigated. The present study aimed to explore the association of chronotypes with meal frequency, physical activity, and demographic factors among the Saudi population. This cross-sectional web-based questionnaire involved 1369 adults (aged 18 years and above) from the general public in Saudi Arabia and was conducted between March and May 2019. Chronotype was assessed using the reduced version of the original Horne and Ostberg morningness-eveningness questionnaire (MEQ). Meal frequencies and demographics data (age, gender, marital status, place of residence, educational level, employment status, income) were obtained. Physical activity level was also obtained using the international physical activity questionnaire. The MEQ scores group individuals into three categories: morning-type, neither-type, and evening-type. The neither-type individuals represented 41.6% (95% confidence interval [CI], 37.5% − 45.6%) of the study population, followed by the morning-type (34.1%; 95% [CI], 29.8% − 38.4%), then the evening-type (24.3%, 95% [CI], 19.6% − 28.9%). Chronotype was significantly associated with age, marital status, employment status and monthly income (All p < 0.05). Significant associations between chronotype with meal frequencies (number of meals per day, breakfast frequency, lunch frequency, and dinner frequency) and physical activity were also observed (All p < 0.05). This study highlights that meal frequencies and physical activity levels are associated with chronotype distribution. Furthermore, demographics, including age, marital status, employment status, and income, were associated with chronotype distribution.

Decreased Long-Term Survival of Patients With Newly Diagnosed Cancer Discharged Home After Unplanned ICU Admission: A Prospective Observational Study.

To compare the 18-month survival between patients with newly diagnosed cancer discharged home after early unplanned ICU admission and those without early unplanned ICU admission; we also evaluated the frequency and risk factors for early unplanned ICU admission. Observational study with prospectively collected data from September 2019 to June 2021 and 18 months follow-up. Single dedicated cancer center in São Paulo, Brazil. We screened consecutive adults with suspected cancer and included those with histologically proven cancer from among 20 highly prevalent cancers. None. The exposure was early unplanned ICU admission, defined as admission for medical reasons or urgent surgery during the first 6 months after cancer diagnosis. The main outcome was 18-month survival after cancer diagnosis, and the main analysis was Cox's proportional hazards model adjusted for confounders and immortal time bias. Propensity score matching was used in the sensitivity analysis. We screened 4738 consecutive adults with suspected cancer and included 3348 patients. Three hundred twelve (9.3%) had early unplanned ICU admission, which was associated with decreased 18-month survival both in the unadjusted (hazard ratio, 4.03; 95% CI, 2.89-5.62) and adjusted (hazard ratio, 1.84; 95% CI, 1.29-2.64) models. The sensitivity analysis confirmed the results because the groups were balanced after matching, and the 18-month survival of patients with early ICU admission was lower compared with patients without early ICU admission (87.0% vs. 93.9%; p = 0.01 log-rank test). Risk factors for early unplanned ICU admission were advanced age, comorbidities, worse performance status, socioeconomic deprivation, metastatic tumors, and hematologic malignancies. Patients with newly diagnosed cancer discharged home after early unplanned ICU admission have decreased 18-month survival compared with patients without early unplanned ICU admission.

Catalytic hydrogen combustion over supported metal catalysts; comparison and kinetic study

Catalytic H2 combustion (CHC) is an efficient way to mitigate H2 slip from industrial processes, overcoming the explosion and NOx emission risks. Although Pt-based catalysts are state-of-the-art catalysts, little is known about the CHC catalytic activity of other transition metals (TMs) and their reaction kinetics. Well-dispersed nano-sized M-γAl2O3 (M = Pt, Ru, Co, Ni, Mo) catalysts are synthesized and characterized with spectroscopic and electron microscopy methods. During the CHC reaction, a competitive reaction between O2, H2 and the catalyst is observed, which leads to partial or complete oxidation of the TMs. Stable CHC performance is attained for Ru-γAl2O3 and Co-γAl2O3 catalysts over 45 h. The kinetically controlled region is determined using a new data acquisition approach. The activation energy and pre-exponential factor are compared between M-γAl2O3 catalysts based on the Arrhenius model. This knowledge is highly valued and allows the design of supported catalysts and optimize the CHC reaction in various applications with different requirements.

Lipid profile and risk factors for neoatherosclerosis after drug-eluting stent implantation in acute coronary syndrome

Predictors of neoatherosclerosis in patients who received primary percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) remain unclear. The aim of this study is to investigate the frequency and risk factors of neoatherosclerosis 1-year after the onset of ACS. This study investigated 83 patients who underwent PCI for ACS followed by 1-year follow-up optical coherence tomography. The patients were categorized into the neoatherosclerosis (n = 11) and non-neoatherosclerosis groups (n = 72). Baseline characteristics, PCI procedures, medical therapies, and blood tests at 1-year, including detailed lipid profiles, were compared between the two groups. Diabetes mellitus was more prominent in the neoatherosclerosis than in the non-neoatherosclerosis group (45% vs. 17 %, respectively, p = 0.03). Total cholesterol (171 ± 37 mg/dL vs. 145 ± 25 mg/dL, respectively, p < 0.01), non-high-density lipoprotein cholesterol (HDL-C) (124 ± 36 mg/dL vs. 94 ± 24 mg/dL, respectively, p < 0.01), low-density lipoprotein cholesterol (94 ± 36 mg/dL vs. 72 ± 19 mg/dL, respectively, p < 0.01), and lipoprotein (a) (Lp[a]) (70 [19-112] mg/dL vs. 10 [3-25] mg/dL, respectively, p = 0.03) at follow-up were significantly higher in the neoatherosclerosis group. Multivariate analysis revealed that neoatherosclerosis was associated with high serum non-HDL-C (odds ratio [OR]: 1.075; 95 % confidence interval [CI]: 1.011-1.144; p < 0.01) and high serum Lp(a) levels (>30 mg/dL) (OR: 11.0; 95 % CI: 1.492-81.02; p = 0.02). Poorly controlled non-HDL-C and Lp(a) would be risk factors of neoatherosclerosis in patients 1-year after ACS.

Frequency and Risk Factors of Deep Venous Thrombosis in Aged Patients with Intertrochanteric Fracture on Admission.

To investigate the frequency of deep vein thrombosis (DVT) in patients aged over 80 years on admission after intertrochanteric femur fracture and to explore the risk factors of DVT. Descriptive study. Place and Duration of the Study: Department of Orthopaedics, China-Japan Friendship Hospital, Beijing, China, from 1st January 2019 to 31st December 2022. A group of patients aged over 80 years with intertrochanteric fracture were included according to the presence or absence of DVT confirmed by ultrasonography on admission. The patients were divided into the non-DVT and DVT groups. Clinical data were retrospectively compared between the two groups and analysed by multivariate logistic regression to screen risk factors of DVT. A total of 130 patients meeting the inclusion criteria were enrolled, and 37 of them had DVT on admission, with a prevalence of 28.5%, including 25 (67.6%) distal peripheral DVT, 11 (29.7%) proximal central DVT, and 1 (2.7%) mixed DVT. The American Society of Anaesthesiologists (ASA) classification, Charlson comorbidity index, the serum levels of D-dimer, fibrinogen degradation products, albumin, potassium, inorganic phosphorus, and calcium showed significant differences between the two groups (p <0.1). Multivariate analysis identified increased D-dimer (>6.005 mg/L), decreased albumin (<36.45 g/L), and reduced potassium (<3.650 mmol/L) as independent factors for DVT in aged intertrochanteric fracture patients (AIFPs). A high incidence of DVT was revealed in AIFPs, and elevated D-dimer levels, reduced albumin levels, and reduced potassium concentrations were shown to be correlated to DVT. Intertrochanteric fracture, Deep vein thrombosis, Aged patients, Risk factor, Multivariate logistic regression.

Early bacteremia following allogeneic hematopoietic stem cell transplantation without antibiotic prophylaxis: epidemiology and antimicrobial resistance

ObjectiveBacteremia is a serious complication in patients undergoing allogeneic hematopoietic stem cell transplantation. The aim of this study was to determine the frequency, epidemiological profile, and risk factors of bacteremia early after allogeneic hematopoietic stem cell transplantation. MethodsAn observational descriptive retrospective study was conducted in patients who received transplants between January 2016 and December 2021. Early bacteremia was defined as blood stream infection occurring between Day 0 and Day 100 after transplantation. ResultsForty episodes of early bacteremia occurred in 36/245 transplanted patients. Fifteen episodes (37.5%) were due to gram-positive bacteria and 25 (62.5%) to gram-negative bacteria. The most frequent species isolated were coagulase negative staphylococci (CoNS) in gram-positive bacteremia (n = 8/15), and Klebsiella species (8/25) and Pseudomonas species (8/25) in gram-negative bacteremia. Twenty-nine episodes of bacteremia (72.5%) occurred during the first 30 days after transplantation with a median time of nine days (range: 0-90 days). Coagulase negative staphylococci were methicillin-resistant in 75% of cases, the only Staphylococcus aureus isolated was methicillin-resistant. All gram-positive bacilli were penicillin-resistant. Gram-negative bacilli were multidrug resistant in 61.5% of cases. In multivariate analysis, bone marrow as source of graft (p-value = 0.02) and cytomegalovirus reactivation (p-value = 0.02) were significantly associated with an increased risk of bacteremia. Mortality attributable to bacteremia was 2.8%. The one-year overall survival was not significantly different between those with and without bacteremia. ConclusionsBacteremia was more frequent within the first 30 days after transplantation indicating the crucial role of neutropenia. An increase in multidrug resistant gram-negative bacteremia was noted.

A low-voltage, high-performing CMOS transistor based on multiple- output operation transconductance amplifier for current mode KHN Universal filter applications

This study proposes a current-mode KHN universal filter design that can perform three standard functions simultaneously: low-pass, high-pass, and band-pass. The circuit is built around a multiple-output operation transconductance amplifier (MO-OTA), which allows for electronically adjustable pole frequency and quality factor by modifying input bias currents (IB). The circuit layout is straightforward, with two MO-OTAs and two grounded capacitors, eliminating the need for external resistors and depending entirely on grounded components. Because of its simplicity, the circuit is suited for use in a tiny, efficient design. The proposed circuit's operation was validated using LT-Spice simulations, and the results were in line with theoretical expectations. The circuit used around 298μW of power at ±0.2V power supply voltages. These results demonstrate the circuit's potential for low-power applications, which are crucial in many modern electronic devices. The suggested current-mode KHN universal filter offers a viable option for combining various filter functions in a single circuit with customizable parameters. Its simplicity, efficiency, and performance qualities make it a feasible choice for incorporation into a variety of electronic systems, allowing for more filter design freedom.

Frequency and risk factors for the development of emergence delirium in children during correction of various forms of strabismus: a prospective observational blinded study

Frequency and risk factors for the development of emergence delirium in children during correction of various forms of strabismus: a prospective observational blinded study

Analysis of the self-healing mechanism of TB compound-modified asphalt based on molecular dynamics

To investigate the intrinsic self-healing behavior of terminal blend (TB)-modified asphalt (TBMA), this study establishes four models of matrix asphalt, TBMA, TBMA containing styrene-butadiene-styrene (TB_SBS), and TBMA containing ethylene vinyl acetate (TB_EVA) based on molecular dynamics, and the self-healing ability of the four types of asphalt was evaluated by means of the diffusion coefficient, diffusion activation energy, and pre-exponential factor. Finally, the study analyzes and validates the self-healing performance of the asphalt through fatigue shear-healing tests. The results showed that the self-healing potentials of the four types of asphalt, as determined by the diffusion coefficient, diffusion activation energy, and pre-exponential factor, were (in descending order) TB_SBS, TBMA, TB_EVA, and matrix asphalt. In addition, the diffusion coefficient of the TBMA was increased relative to the matrix asphalt, SBS polymer further increased the diffusion coefficient, and EVA modifier had an inhibitory effect, which was related to the viscoelasticity and mechanical performance of the material. Besides, the diffusion coefficient enhancement effect of the SBS modifier on the TBMA was greater than the inhibition effect, which mainly derived from the enhancement of the diffusion coefficient of lightweight components in significantly enhancing the self-healing ability the TBMA. From microscopic and macroscopic scales, the shear-fatigue healing tests showed excellent correlation with the simulation results, demonstrating that molecular dynamics can be used to model the self-healing process of asphalt.

Vibration analysis of a composite sandwich plate with a viscoelastic auxetic core, FG-CNTRC interior, and MEE–FGP exterior face sheets

This research has been conducted to analyze the free vibration behavior of a five-layered composite plate with a viscoelastic auxetic core. The plate comprises a viscoelastic auxetic core layer, functionally graded carbon nanotube reinforced composite (FG-CNTRC) interior, and magneto-electro-elastic functionally graded porous (MEE–FGP) exterior skins, which is rested on Winkler–Pasternak foundation. According to the magnetic–electric boundary conditions and Maxwell equations, the electric and magnetic potentials of the plate are determined. The macro-mechanical properties of the auxetic core have been derived based on Gibson’s model; the three-parameter Zener model has also been utilized to describe its viscoelastic behavior. Additionally, the equations of motion of the plate are obtained and solved by using Reddy’s third-order shear deformation theory (TSDT) and the Galerkin method, respectively. Moreover, various aspects of the current research have been validated by comparing the numerical results with those reported in the literature section. Overall, in the numerical result section, the effects of different parameters and conditions such as geometrical parameters, position of the plate’s interfaces of layers (thickness of the core and face layers), various distribution patterns and volume fractions of both CNT and porosity, external work parameters of the MEE skins, boundary conditions, Winkler–Pasternak stiffness coefficients, the relaxation time, and other parameters of the viscoelastic core on the natural frequency and loss factor of the composite plate are represented.

Seroprevalence and Risk Factors for Hepatitis B, Hepatitis C, and HIV in a Substance Abuse Treatment Center.

Alcohol and substance use disorders are important public health problems with an increased risk for bloodborne and sexually transmitted infections. To determine the frequency and risk factors of hepatitis B, hepatitis C and HIV in individuals with drug and alcohol addiction. This prospective study was conducted in the outpatient clinic of Alcohol and Substance Abuse Treatment and Education Center (ASATEC), Izmir, Turkey. Detailed anamneses were taken from alcohol and/or drug addicts who applied to the outpatient clinic; HBV, HCV, HIV serology results in the last 6 months were examined. The study group consisted of 478 persons, including 112 (23.4%) alcohol addicts, 322 (67.4%) substance addicts, and 44 (9.2%) combined alcohol and substance addicts. The mean age of the cases was 32 ± 11 years and 432 (90.4%) were male. Drug injection and needle sharing was recorded in 16.5% and 9.8% of participants, respectively. Hepatitis B surface antigen (HBsAg) positivity was found in 2.7%, anti-HCV positivity in 9.6% and HIV Ag/Ab positivity in 1.9% of the cases. Among patients using intravenous drugs, HBsAg positivity was found in 2%, anti-HCV positivity in 55%, while HIV Ag/Ab positivity was not detected. A history of sexually transmitted disease was a risk factor for HBsAg, HIV Ag/Ab positivity. Intravenous drug use, needle sharing and ecstasy use were determined as risk factors for anti-HCV positivity. Risky behaviors for HBV, HCV and HIV transmission are high in alcohol and substance addicts. The use of ecstasy is a novel risk factor for HCV transmission.

Frequency and Risk Factors Associated with Prematurity: A Cohort Study in a Neonatal Intensive Care Unit.

Background/Objectives: Prematurity rates remain high and represent a challenge for the public health systems of any country, with a high impact on neonatal mortality. This study aimed to evaluate the frequency and environmental and maternal-fetal risk factors for premature birth in a cohort of parturient women, with their newborns monitored in a neonatal intensive care unit at a private reference hospital. Methods: A cohort was carried out between 2013 and 2018 among parturient women living in a capital city in the Northeast of Brazil whose newborns were admitted to the neonatal intensive care unit. This study was approved by the Research Ethics Committee of the University of Fortaleza. The information collected comprised data from both medical records and hydrosanitary data from maternal homes. Results: The prevalence of prematurity among live births (n = 9778) between 2013 and 2018 at this hospital was 23%. The frequency of prematurity among those eligible (n = 480) was 76.9%, and the frequency of eligible premature babies (n = 369) in relation to the total number of births in this period was 3.8%. In the multivariate analysis, the significant risk factors for prematurity were primigravida (RR = 1.104, 95%CI: 1.004-1.213) and hypertensive syndromes during pregnancy (RR = 1.262, 95%CI: 1.161-1.371), and the significant protective factor was the highest number of prenatal consultations (RR = 0.924, 95%CI: 0.901-0.947). Conclusions: This study contributes to providing greater visibility to prenatal care and the understanding of complications during pregnancy and childbirth care. These results indicate the need to implement public policies that promote improvements in the population's living conditions and care for pregnant women to reduce premature births and, consequently, neonatal and infant mortality.

An integral model for determining the temperature-dependent interfacial energy and pre-exponential factor during the metastable zone width cooling process

By incorporating a temperature-dependent function of interfacial energy and a temperature-dependent pre-exponential factor inversely proportional to the solution viscosity, an integral model was developed according to classical nucleation theory to retrieve the nucleation parameters from the metastable zone width (MSZW) data. The developed model was applied to determine the temperature-dependent interfacial energy and pre-exponential factor during the cooling process from the MSZW data for phenacetin in ethanol experimentally measured in this work. For comparison, the interfacial energy and pre-exponential factor for phenacetin in ethanol at various operating temperatures were determined from the induction time data based on the conventional method. The results indicated that the temperature-dependent interfacial energy and pre-exponential factor for phenacetin in ethanol obtained from the MSZW data based on the developed model were consistent with those obtained from the induction time data based on the conventional method.

Recurrence after primary salivary gland carcinoma: Frequency, survival, and risk factors.

Primary salivary gland carcinomas (SGC) are rare neoplasms that present therapeutic challenges especially in recurrent tumors. The aim of this study was to investigate the incidence and distribution of tumor recurrence, associated risk factors, and survival. This analysis includes data from 318 patients treated for SGC between 1992 and 2020. Survival analysis was performed using the Kaplan-Meier method. Univariate and multivariate analyses were used to identify risk factors associated with recurrence. 21.7% of the patients developed recurrent disease after a mean of 38.2 months. In multivariate analysis, positive-resection margins, vascular invasion, and tumor localization in the submandibular gland and small salivary glands were independent factors for recurrence. The 5-year overall survival was 67%, the 5-year disease-free survival was 54%. Tumor recurrence in SGC occurred in one out of five patients. In highly aggressive entities and patients with risk factors, treatment intensification should be considered.

Kinetics study on the low-temperature soda roasting of boron-rich blast furnace slag

The method of preparing borax by low-temperature soda roasting and water leaching of boron-rich blast furnace slag (BRBFS) is a novel method for extracting boron from BRBFS. In order to further improve the water leaching rate of boron, this article mainly studied the low-temperature soda roasting kinetics of BRBFS. The effects of roasting temperature and Na2CO3 addition on the water leaching rate of boron were investigated. The results demonstrate that when the amount of Na2CO3 added is four times of the theoretical amount, the kinetics of NaBO2 formation can be described by the Nucleation (Avrami) model in the temperature range of 600–700 °C. The corresponding apparent activation energy is 54.45 kJ/mol, and the apparent frequency factor is 215.16 h−1. It was found that at a roasting temperature of 700 °C,when the amount of sodium carbonate added is twice, three times, and four times of the theoretical amount, the kinetics of NaBO2 formation matches with 3-D Diffusion (Jander) model, Nucleation and Growth (Avrami-Erofeev) model, and Nucleation (Avrami) model, respectively. With an increase in the amount of Na2CO3 added, the rate-controlling step for the formation of NaBO2 transitions from being diffusion-controlled to nucleation-controlled.

Exploring the thermoluminescence characteristics of smartphone screen safety glasses for retrospective dosimetry applications

In clinical settings, standard dosimeters might miss radiation mishaps. Retrospective dosimeters could help to track personnel (such as patients and other staff who don't wear dosimeters) exceeding safe limits and assess long-term exposure trends. This study has investigated key thermoluminescence (TL) dosimetric characteristics, including the glow curve structure, dose-response, energy dependence, sensitivity and fading of various safety glasses that are used as screen protectors of smartphones subjected to photon irradiation. Among the studied glasses, the HD Anti-Peep safety glass for iPhone has been found to exhibit a linear dose-response with a regression coefficient of 99% within the dose range of 2–10 Gy. Moreover, all the safety glasses showed independence with respect to photon energy of 6 MV and 10 MV. The TL glow curves of the samples showed a broad glow peak between 125 °C and 325 °C at 10 Gy. The TL kinetic parameters of the safety glasses were also studied by analyzing the glow curves using the peak shape and initial rise method. The geometric factor (μg) is found to be within the range of 0.43–0.53, which indicates the suitability of applying Chen's general-order formula to calculate the kinetic parameters such as activation energy, frequency factor and trap lifetime. The activation energy (E) and frequency factor (s) are found in the range of 0.31–0.54 eV and 4.55 × 103 to 2.12 × 106 s−1 respectively obtained via the peak shape method. The relatively long trap lifetime and observed thermoluminescence features indicate that the HD Anti-Peep safety glass offers a better option to estimate dose retrospectively to ensure the safety of human health.

Bilateral Subconjunctival Hemorrhage (SCH) Following Delivery

Introduction: Subconjunctival hemorrhage (SCH) occurs when blood enters from the conjunctival or episcleral blood vessels into the subconjunctival space. SCH is classified as traumatic and non-traumatic (NTSCH). Microvascular diseases and increased intraabdominal pressure are associated with NTSCH; consequently, SCH can develop after vaginal delivery. However, reports regarding postpartum SCH are still scarce. This study aims to enhance awareness and comprehension of postpartum SCHs rather than minimize their significance. Case Presentation: A 17-year-old female presented with bilateral redness in both eyes one day post-delivery with no other ocular complaints. There were no complications in pregnancy and labor. The patient had no medical history of anticoagulant usage, trauma, hypertension, or blood disorders. Ophthalmic examination revealed visual acuity 20/20 on both eyes and bilateral subconjunctival hemorrhage, while other examinations were unremarkable. Treatment included a cold compress for 24 hours, followed by warm compresses every two hours on both eyes. Pharmacological therapy included artificial tears and naphazoline eye drops. Conclusions: Increased intra-abdominal pressure during labor can contribute to SCHs. While spontaneous resolution is common, accurate differentiation of SCH etiology is crucial for effective management. Obstetricians and ophthalmologists must collaborate to identify risk factors early, including routine eye screenings during the perinatal period, to enhance patient comfort and safety. Furthermore, additional research endeavors and investigations are necessary to deepen our understanding of the frequency and risk factors associated with postpartum SCHs and to develop effective prevention and treatment measures.