New Insights into Thermal Degradation Products of Long-Chain Per- and Polyfluoroalkyl Substances (PFAS) and Their Mineralization Enhancement Using Additives.

The products of incomplete destruction (PIDs) of per- and polyfluoroalkyl substances (PFAS) represent a substantial ambiguity when employing thermal treatments to remediate PFAS-contaminated materials. In this study, we present new information on PIDs produced in both inert and oxidative environments from five long-chain PFAS, including three now regulated under the U.S.

A comprehensive Review into Emission Sources, Formation Mechanisms, Ecological Effects, and Biotransformation Routes of Halogenated Polycyclic Aromatic Hydrocarbons (HPAHs).

Halogenated polycyclic aromatic hydrocarbons (HPAHs, H = F, Cl, Br) are a new class of PAHs derivatives that mainly originate from the incomplete combustion of halogen-laden materials and via metallurgical operations. These compounds circulate extensively in various environmental matrices. This survey provides a comprehensive review on governing synthesis routes of HPAHs, their environmental occurrence, and their health and ecological effects.

Effect of Hydration Forms and Polymer Grades on Theophylline Controlled-Release Tablet: An Assessment and Evaluation.

Background: Drug release from controlled release delivery systems is influenced by various factors, including the polymer's grade and the drug's hydration form. This study aimed to investigate the impact of these factors on the controlled release of theophylline (THN). This research compares the monohydrate form found in branded products with the anhydrous form in generic equivalents, each formulated with different polymer grades.

Predicting the Decomposition Mechanism of the Serine α-Amino Acid in the Gas Phase and Condensed Media.

Comprehending the nitrogen combustion chemistry during the thermal treatment of biomass demands acquiring a detailed mechanism for reaction pathways that dictate the degradation of amino acids. Serine (Ser) is an important α-amino acid that invariably exists in various categories of biomass, most notably algae. Based on density functional theory (DFT) coupled with kinetic modeling, this study presents a mechanistic overview of reactions that govern the fragmentation of the Ser compound in the gas phase as well as in the crystalline form.

Prediction of Thermogravimetric Data in the Thermal Recycling of e-waste Using Machine Learning Techniques: A Data-driven Approach.

The release of bromine-free hydrocarbons and gases is a major challenge faced in the thermal recycling of e-waste due to the corrosive effects of produced HBr. Metal oxides such as FeO (hematite) are excellent debrominating agents, and they are copyrolyzed along with tetrabromophenol (TBP), a lesser used brominated flame retardant that is a constituent of printed circuit boards in electronic equipment. The pyrolytic (N) and oxidative (O) decomposition of TBP with FeO has been previously investigated with thermogravimetric analysis (TGA) at four different heating rates of 5, 10, 15, and 20 °C/min, and the mass loss data between room temperature and 800 °C were reported.

Chemical Investigation on the Mechanism and Kinetics of the Atmospheric Degradation Reaction of Trichlorofluoroethene by OH⋅ and Its Subsequent Fate in the Presence of O /NOx.

The M06-2X/6-311++G(d,p) level of theory was used to examine the degradation of Trichlorofluoroethene (TCFE) initiated by OH⋅ radicals. Additionally, the coupled-cluster single-double with triple perturbative [CCSD(T)] method was employed to refine the single-point energies using the complete basis set extrapolation approach. The results indicated that OH-addition is the dominant pathway.

Monatomic reactions with single vacancy monolayer h-BN: DFT studies.

Hexagonal boron nitride (h-BN) has been widely utilized in various strategic applications. Fine-tuning properties of BN towards the desired application often involves ad-atom adsorption of modifying its geometries through creating surface defects. This work utilizes accurate DFT computations to investigate adsorption of selected 1st and 2nd row elements (H, Li, C, O, Al, Si, P, S) of the periodic table on various structural geometries of BN.

Combating toxic emissions from thermal recycling of polymeric fractions laden with novel brominated flame retardants (NBFRs) in e-waste: an in-situ approach using Ca(OH).

Legacy brominated flame retardants (BFRs) in printed circuit boards are gradually being replaced by novel BFRs (NBFRs). Safe disposal and recycling of polymeric constituents in the polymeric fractions of e-waste necessitate the removal of their toxic and corrosive bromine content. This is currently acquired through thermal recycling operations involving the pyrolysis of BFRs-containing materials with metal oxides.

Mechanochemical debromination of allyl 2,4,6-tribromophenyl ether (TBP-AE): optimization of the operational conditions.

Allyl 2,4,6-tribromophenyl ether (TBP-AE) is a flame retardant that is added to plastics to improve their fire resistance. This kind of additive is hazardous to both human health and the environment. As any other BFRs, TBP-AE resists photo-degradation in the environment and hence materials laden with TBP-AE are to be dibrominated to avoid environmental pollution.

Prediction of Thermogravimetric Data in Bromine Captured from Brominated Flame Retardants (BFRs) in e-Waste Treatment Using Machine Learning Approaches.

The principal objective in the treatment of e-waste is to capture the bromine released from the brominated flame retardants (BFRs) added to the polymeric constituents of printed circuits boards (PCBs) and to produce pure bromine-free hydrocarbons. Metal oxides such as calcium hydroxide (Ca(OH)) have been shown to exhibit high debromination capacity when added to BFRs in e-waste and capturing the released HBr. Tetrabromobisphenol A (TBBA) is the most commonly utilized model compound as a representative for BFRs.

Degradation of tetrabromobisphenol A (TBBA) with calcium hydroxide: a thermo-kinetic analysis.

Thermal treatment of bromine-contaminated polymers (, as in e-waste) with metal oxides is currently deployed as a mainstream strategy in recycling and resources recovery from these objects. The underlying aim is to capture the bromine content and to produce pure bromine-free hydrocarbons. Bromine originates from the added brominated flame retardants (BFRs) to the polymeric fractions in printed circuits boards, where tetrabromobisphenol A (TBBA) is the most utilized BFR.

Oxidative and pyrolytic decomposition of an evaporated stream of 2,4,6-tribromophenol over hematite: A prevailing scenario during thermal recycling of e-waste.

Brominated flame retardants (BFRs) constitute a major load in the polymeric fraction of e-waste. Degradation of BFRs-laden plastics over transition metal oxides is currently deployed as a mainstream strategy in the disposal and treatment of the non-metallic segment of e-waste. However, interaction of pyrolysis's products of BFRs with transition metal oxides is well-known to facilitate the formation of notorious pollutants.

Formation of perfluorocarboxylic acids (PFCAs) from thermolysis of Teflon model compound.

It has been widely postulated that thermal degradation of polytetrafluoroethylene (PTFE; commercially known as Teflon) under the presence of moisture presents a likely source for the formation of the notorious perfluorocarboxylic acids (CF(CF)CO(OH) PFCAs) and perfluorinated aldehydes (CF(CF)CO(F/H). Thus, deployment of objects laden with Teflon at the peak of their thermal stability may contribute to the atmospheric budget of PFCAs. However, the underlying mechanism remains largely speculative.

Manifestations of COVID-19 infection in children with malignancy: A single-center experience in Jordan.

Background: The coronavirus disease 2019 (COVID-19) has been the cause of a global health crisis since the end of 2019. All countries are following the guidelines and re-commendations released by the World Health Organization to decrease the spread of the disease. Children account for only 3%-5% of COVID-19 cases.

Bromination mechanisms of aromatic pollutants: formation of Br and bromine transfer from metallic oxybromides.

Bromination mechanisms of aromatic pollutants assume a chief contribution in the observed yields and pattern's distribution of a wide array of dioxin-like toxicants. However, salient features of the governing pathways remain largely speculative. This study presents detail mechanistic insights into two commonly discussed routes; namely: surface-assisted conversion of HBr into Br and direct bromine transfer from oxybromides into a benzene ring.

On the formation chemistry of brominated polycyclic aromatic hydrocarbons (BrPAHs).

Brominated polycyclic aromatic hydrocarbons (BrPAHs) have been consistently detected in various environmental matrices, and measured at alarming rates in stack emissions. However, formation mechanisms and bromination patterns of BrPAHs remain unclear. This contribution constructs detailed mechanistic pathways for the synthesis of selected BrPAHs (namely bromine-bearing naphthalene, acenaphthylene, anthracene, and phenanthrene).

Thermal decomposition of heptafluoropropylene-oxide-dimer acid (GenX).

Incineration appears as a viable strategy in the disposal of the notorious perfluoroalkyl substances (PFASs) in a process that typically leads to fluorine mineralization. Central in the design of such operation is to comprehend the underlying chemical mechanisms that dictate thermal fragmentation of PFASs into smaller perfluorinated cuts and HF. Among notable short-chain PFASs entities is the heptafluoropropylene-oxide-dimer acid (HFPO-DA, CFC(O)OH), commercially known as GenX synthesized as a possible replacement of other PFASs compounds.

Removal of Bromine from the non-metallic fraction in printed circuit board via its Co-pyrolysis with alumina.

The effectiveness of a recycling approach of the printed circuit board (PCBs), and, thus, the quality of polymeric constituents, primarily rests on the capacity to eliminate the bromine content (mainly as HBr). HBr is emitted in appreciable quantities during thermal decomposition of PCB-contained brominated flame retardants (BFRs). The highly corrosive, yet relatively reactive HBr, renders recovery of bromine-free hydrocarbons streams from brominated polymers in PCBs very challenging.

An Insight into Geometries and Catalytic Applications of CeO from a DFT Outlook.

Rare earth metal oxides (REMOs) have gained considerable attention in recent years owing to their distinctive properties and potential applications in electronic devices and catalysts. Particularly, cerium dioxide (CeO), also known as ceria, has emerged as an interesting material in a wide variety of industrial, technological, and medical applications. Ceria can be synthesized with various morphologies, including rods, cubes, wires, tubes, and spheres.

Hematopoietic Stem Cell Transplantation During the Era of COVID-19 in Queen Rania Children's Hospital.

Background: Corona virus disease 2019 (COVID-19) is causing a health crisis nowadays, and all countries are following the recommendations of the WHO to decrease the spread of the disease. Till now, few data are available regarding the clinical course, severity of the disease and the duration of infectivity of COVID-19 in patients received Hematopoietic Stem Cell Transplantation (HSCT).

Objective: To evaluate the medical protocols and outcome of patients who underwent HSCT during the pandemic of COVID-19.

Temperature-dependent profiles of dioxin-like toxicants from combustion of brominated flame retardants.

Literature provides detailed mechanisms underpinning the formation of a wide array of bromine (Br)-containing molecules with a prime focus on dioxin-like compounds. However, from a more applied point of view, the practical deployment of attained thermo-kinetic parameters remains inadequate in the absence of a robust kinetic model that connects bromine transformation at the molecular level with pertinent experimental observations. Herein and to fill in this gap, this study constructs a chemical kinetic model to account for the "homogenous gas phase" emission of Br-aromatic pollutants from the oxidative thermal decomposition of a monobromobenzene molecule (MBZ).

Thermal decomposition of perfluorinated carboxylic acids: Kinetic model and theoretical requirements for PFAS incineration.

Thermal decomposition of high-fluorine content PFAS streams for the disposal of old generations of concentrates of firefighting foams, exhausted ion-exchanged resins and granular activated carbon, constitutes the preferred method for destruction of these materials. This contribution studies the thermal transformation of perfluoropentanoic acid (CFC(O)OH, PFPA), as a model PFAS species, in gas-phase reactions over broad ranges of temperature and residence time, which characterise incinerators and cement kilns. Our focus is only on gas-phase reactions, to formulate a gas-phase submodel that, in future, could be used in comprehensive simulation of thermal destruction of PFAS; such comprehensive models will need to comprise fluorine mineralisation on flyash and in clinker material.

Low-temperature oxidation of monobromobenzene: Bromine transformation and yields of phenolic species.

Brominated benzenes and phenols constitute direct precursors in the formation of bromine-bearing pollutants; most notably PBDD/Fs and other dioxin-type compounds. Elucidating accurate mechanisms and constructing robust kinetic models for the oxidative transformation of bromobenzenes and bromophenols into notorious Br-toxicants entail a comprehensive understanding of their initial oxidation steps. However, pertinent mechanistic studies, based on quantum chemical calculations, have only focused on secondary condensation reactions into PBDD/Fs and PBDEs.

The influence of anesthesia type on perioperative maternal glycemic-stress response during elective cesarean section: A prospective cohort study.

Background: It has been known that the type of anesthesia can affect the stress response to surgery in form of hyperglycemia. This study aims to evaluate and compare the influence of general anesthesia (GA) and spinal anesthesia (SA) on pregnant women who are scheduled to undergo cesarean section (CS) and to understand the impact of obstetrical factors on the maternal hyperglycemic-stress response during CS.

Methods: Prospectively, we identified, assessed and followed those pregnant women who were scheduled to undergo elective CS surgery.