Studies on the Decomposition of Selected Brominated Flame Retardants (BFRs) and Formation of Polybrominated Dibenzo-p-dioxins and Dibenzofurans (PBDD/Fs) and Mixed Halogenated Dibenzo-p-dioxins and Dibenzofurans (PXDD/Fs)

Brominated flame retardants (BFRs) are bromine-bearing hydrocarbons added or applied to materials to increase their fire resistance. As thermal treatment or recycling activities are common disposal methods for BFR-laden objects, it is essential to determine the precise decomposition chemistry of BFRs at elevated temperatures, and their transformation pathways into hazardous pollutants. Sunlight can trigger the photodecomposition of BFRs, either during the life cycle of treated objects, or when emitted to the environment after disposal. Therefore, knowledge of the geometric and electronic structures of BFRs is of chief importance when tracking their fate in the ambient environment. Although BFR decomposition mainly occurs in a condensed phase, gas phase reactions also contribute significantly to their overall decay and subsequent fragmentation into brominated pollutants. Thermal degradation of BFRs often proceeds in the presence of bromine atoms which inhibit complete combustion. Therefore, under thermal conditions such as smouldering, municipal waste incineration, pyrolysis, thermal recycling, uncontrolled burning and fires, BFRs degrade to form brominated products of incomplete combustion (BPICs). Thermal degradation of BFRs produces potent precursors to polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs). Co-combustion of BFR-containing objects with a chlorine source (e.g., polyvinyl chlorides) results in the emission of significant concentrations of mixed halogenated dibenzo-p-dioxins and dibenzofurans (i.e., PXDD/Fs; X = Br, Cl). In this thesis, we investigated the thermochemical parameters of bromochlorophenols (BCPhs) and the photodecomposition properties of major BFRs and their derived brominated phenols (BPhs). We scrutinised the formation of brominated and non-brominated products that evolved during the thermal decomposition of major BFR i.e., tetrabromobisphenol A (TBBA), through experimental measurements coupled with accurate quantum chemical calculations. We acquired thermo-kinetic parameters as well as mechanistic routes pertinent to the destruction of TBBA. We illustrated reaction networks for the synthesis of PXDD/Fs from BPhs and chlorinated phenols (CPhs). Similarly, we described pathways leading to the formation of PBDFs and polybrominated diphenylethers (PBDEs) from brominated benzenes (BBzs). We critically reviewed the literature on BFR thermal decomposition with specific foci on underlying mechanisms, decomposition products, the influence of the polymeric matrix, metallic content and operational conditions. As BCPhs are direct building blocks for the formation of PXDD/Fs, we computed the thermochemical parameters of their complete series. We calculated standard enthalpies of formation, entropies, heat capacities and bond dissociation enthalpies (BDHs) of O-H bonds for the complete series of BCPhs. Values of the acid dissociation constant (pKa) were estimated based on an accurate thermodynamic cycle incorporating solvation and protonation energies. Calculated values of BDHs of O-H bonds in BCPhs vary slightly with the change in degree and pattern of halogenation. Gibbs energies of solvation of BCPhs in water are highly exergonic, with their values increasing with the degree of halogen substitution. Values of pKa dictate that BCPhs characterised by high degrees of halogenation display stronger acidity and dissociate more easily in aqueous media (i.e., they are stronger acids than lower substituted phenols). Photolysis and photochemical decomposition are important channels for the degradation of halogenated organic pollutants in the environment. Therefore, we performed density functional theory (DFT) and time-dependent density functional theory (TDFT) calculations in order to derive the photodecomposition properties of major deployed BFRs and congeners of BPhs in both gaseous and aqueous media. We clarified the effect of degree and pattern of bromination on the photodebromination of selected brominated aromatic compounds based on several molecular descriptors; namely, geometries of the ground (S0) and electronically first excited (S1) states, values of the HOMO-LUMO energy gap (EH-L) and atomic charges on bromine atoms (qBr). Molecules exhibit different geometries in the S0 and S1 states and C-Br bonds elongate upon S0 → S1 transitions. In agreement with the recent findings on PBDEs, we found that the photoreactivity of bromine atoms in investigated BFRs and BPhs followed the sequence of ortho > meta > para. The bromine atom connected to the ortho-position holds the highest positive atomic charge and, thus, experiences the greatest lengthening of C-Br bonds in the S1 state, in both gaseous and an aqueous media, prompting their reductive debromination. Excitation energies decrease linearly with increasing numbers of bromine substituents, and congeners with a high degree of bromination photodecompose more readily than lower brominated isomers. Computed values of EH-L for major BFRs and their non-brominated molecules inferred that the number of bromine substituents and the nature of the structure (aromatic/non-aromatic) contributes significantly towards the photoreactivity of molecules. We conducted gas phase thermal decomposition of TBBA using a laboratory-scale tubular reactor. Our main focus was to identify pollutants arising in the temperature range of 673 – 1123 K following evaporation of TBBA in the gas phase. The identification and quantitation involved the use of a gas chromatograph – triple quadrupole mass spectrometer (GC-QQQMS) instrument, functioning in multiple reaction monitoring (MRM) and total ion current (TIC) modes. Product analysis revealed that thermal decomposition of TBBA commenced at 723 K. The major decomposition products were HBr, di-tribrominated bisphenols, benzene, phenol, mono-tribrominated congeners of benzene and phenol, brominated and non-brominated alkylated benzenes, benzofuran, bromobenzofuran, dibenzofuran, bromine substituted polyaromatic hydrocarbons (PAHs), biphenyl and biphenylene. We observed that, most of the decomposition products evolved in trivial concentrations at a temperature of 773 K and peaked at around 923 – 973 K. Higher temperatures favour the generation of non-brominated products. In this chapter, we have performed quantum chemical calculations to derive the degradation pathways of TBBA and to illustrate routes for the formation of brominated and non-brominated species. We constructed formation mechanisms related to the emission of PBDD/Fs in systems involving BFRs. In particular, we investigated formation corridors of (i) PXDD/Fs from the coupling reactions of 2-chlorophenoxy (2-CPhxy) and 2-bromophenoxy (2-BPhxy) radicals, (ii) PBDFs and PBDEs synthesis from the condensation reaction of monobromobenzene (MBBz) and a 2-BPhxy radical. The coupling reactions of 2-BPhxy and 2-CPhxy radicals produce keto-ether (through the additions of a phenoxy O at ortho C(H), C(Cl) and C(Br) sites) and diketo (at ortho positions to C–C bridges) structures. Keto-ethers act as direct intermediates for the formation of dioxin moieties such as dibenzo-p-dioxin (DD), 1-monochlorodibenzo-p-dioxin (1-MCDD), 1-monobromodibenzo-p-dioxin (1-MBDD), 1-bromo-6-chlorodibenzo-p-dioxin (1-B,6-CDD) and 1-bromo-9-chlorodibenzo-p-dioxin (1-B,9-CDD) molecules. Diketo adducts initiate the formation of furan species, i.e., 4-monochlorodibenzofuran (4-MCDF), 4-monobromodibenzofuran (4-MBDF) and 4-bromo-6-chlorodibenzofuran (4-B,6-CDF) compounds, through interconversion and rearrangement reactions. We found that, these mechanisms of formation, commencing from halogenated phenoxy radicals, are largely insensitive to patterns and degrees of halogenation on meta and para sites. It follows that, our developed mechanistic and kinetic factors of reactions involving 2-BPhxy and 2-CPhxy should also apply to higher halogenated phenoxy radicals. We explored the initial oxidative decomposition pathways of monobromobenzene (MBBz) in the generation of BPhxy radicals and examined the possible dimerisation reactions of MBBz and 2-BPhxy. It was found that, the coupling of MBBz and 2-BPhxy results in the generation of twelve pre-PBDF intermediates, of which four can also serve as building blocks for the synthesis of PBDEs. The resonance-stabilised structure of the o-BPhxy radical accumulates more spin density character on its phenoxy O atom (30.9 %) in reference to ortho-C and para-C sites. Thus, the formation of the pre-PBDE/pre-PBDF structures via O/o-C couplings advances faster, as it requires lower activation enthalpies (79.2 – 84.9 kJ mol-1) than the pre-PBDF moieties, which arise via pairing reactions involving o-C(H or Br)/o-C(H or Br) sites (97.2 – 180.2 kJ mol-1). Kinetic analysis indicates that the O/o-C pre-PBDE/pre-PBDF adducts self-eject the out-of-plane H atoms to produce PBDEs, rather than undergo a three-step mechanism that forms PBDFs. Since the formation mechanisms of PBDFs and PBDDs are typically only sensitive to the bromination at ortho positions, the results reported herein also apply to higher brominated isomers of BBzs. Overall, this thesis provides novel and comprehensive information on the thermochemical properties of the complete series of BCPhs (potential precursors to PXDD/Fs) and the electronic/structural characteristics of BFRs and their derived BPhs, with regards to their photodecomposition. To gain an insight into the degradation of TBBA once it has evaporated, this thesis examines the pure gas phase decomposition of TBBA and suggests mechanisms by which the experimentally-detected volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) are generated. Furthermore, this thesis explores the role of BPhs and CPhs as building blocks for the formation of PXDD/Fs, and computes their parameters. We also elucidate reaction pathways and thermo-kinetic parameters for PBDFs and PBDEs produced by the oxidation of BBzs

A Clinical Audit of blood component transfusion practices in Paediatric intensive care unit of a Tertiary Care Hospital, Rawalpindi

Background: To audit the practices involved in blood component transfusion in the management of patients in paediatric intensive care unit of our hospital and to determine the appropriateness of transfusion after comparing them with clinical practice guidelines recommended by Royal Children Hospital (RCH). Methods: All patients admitted in pediatric intensive care which were managed with blood component transfusions were retrospectively audited for 8 weeks. Management details including indications of transfusion and its appropriateness were recorded. Clinical practice guidelines recommended by Royal Children Hospital (RCH) were used as standards. Results: One hundred and ninety-two transfusions were done during the study period out of which 58 percent were done to males and 41 percent to females. Majority of transfusions were done in infants (44%) and O Positive blood group was found rampant among blood groups of all recipients (33.3%). Red cell concentrates were predominantly (55.7%) and appropriately (72%) transfusion among all blood components. Platelet concentrates were most inappropriately transfused (57%) followed by fresh frozen plasma (54%) and red cell concentrates (27%). There was significant percentage of inappropriate transfusion of all blood components (p=0.00). Conclusion: All blood components were significantly found inappropriately transfused, commonest component being platelet concentrates

Impact of Dietary Counselling to Improve Nutritional Status of Hemodialysis Patients

Proper nutrition may reverse the malnutrition and can modulate renal function in hemodialysis patients. In majority of the dialysis units in Pakistan, nutritional advice is given by health professionals working in dialysis. We compared the impact of dietary counseling by a renal dietitian, on nutritional status with that by health professionals working in dialysis units in patients undergoing maintenance hemodialysis. Nutritional assessments were made using subjective global assessment (SGA) scale, which combines assessment of intake, physical findings, and functional status. Two hundred and seventy‑seven patients undergoing hemodialysis from two renal care units in Hayatabad Medical Complex Peshawar and Lahore Gernal Hospital Lahore Pakistan, were enrolled (138 patients in control group, 139 in experimental group). In the experimental group, patients were given repeated dietary counseling by a renal dietician, whereas control group patients were provided with the necessary nutritional information by another health professional. Detailed nutritional, biochemical, and SGA assessment were done on all of them at the beginning and completion of study after 6 months. Patients were categorized as well‑nourished (WN) (SGA = 1–14), mild to moderate malnourishment (MMM) (SGA = 15–35), and severe malnutrition (SM) (SGA = 36–49). In the present study, the overall malnutrition rate at baseline was 95.3%, and it dropped down to 91.7% after 6 months after nutritional counseling. In the experimental group, malnutrition status decreased from 97.2% to 89.8%, whereas in the control group, malnutrition situation remained same. Compared to baseline, in the control group, there was no improvement in the WN group. However, a shift has been observed from MMM group to SM group suggesting more number of patients are becoming malnourished. Contrarily, in the experimental group, an improvement of +7.2% in WN group and +14.3% in MMM group and a drop of −21.6% in severe malnourished group suggesting more number of patients gaining nutrition. The present study observed a significant improvement in nutritional status of patients who received counseling by the renal dietician. The reduction in SGA score was independent of reductions in serum creatinine and blood urea levels Keywords: Dietary Counselling, Nutritional Status, Hemodialysis Patients DOI: 10.7176/JMPB/55-16 Publication date:May 31st 201

Factors Influencing Job Satisfaction of Employees in Telecom Sector of Pakistan

The telecom industry plays an important role in the underpinning of a country’s economy. This study is aimed at getting a clearer view of the level of satisfaction of the employees in various telecom companies. The main concerns are the relative importance and need of different job satisfaction factors and how they contribute to the overall satisfaction of the employees. Another field of focus is the impact of different things, such as experience, age and sex on job satisfaction. The results deduced represent employee relations, salary, fringe supervision, and efficiency as the most important factors influencing job satisfaction. It was seen that job satisfaction was good in telecommunication companies This paper was utilized in understanding the importance of the environment in which the employees work, pay, fairness, promotion, job security, supervisors, and co-worker relationships and their effect on job satisfaction. All telecom companies Ufone, Zong, Telenor, Warid telecom, Pakistan Telecommunication and Mobilink were visited to collected data. Data was quantitatively collected through close-ended questionnaires with a sample size of 200 telecom sector employees. Data was analyzed through correlation and multiple regression using SPSS software and results were significant. The overall job satisfaction of the employees in the telecom sector is at the positive level. Hence, this research was mainly undertaken to investigate on the significance of factors such as working conditions, pay and promotion, job security, fairness, relationship with co-workers and supervisors in affecting the job satisfaction. This paper presents a comprehensive diagnosis of job satisfaction indices of telecom sector, the factors causing the dissatisfaction & suggestions to improve them. Keywords: Job Satisfaction, Job Dissatisfaction, employees, telecom sector, Pakistan

An Analytical Study on National Education Policy 2009: Teacher Education Perspective

The purpose of this study was to review the National Education Policy 2009 in teacher education perspective and to explore the teacher educators’ opinions about National Education Policy 2009 in teacher education perspective. This study contained two parts. For the first part, content analysis was used to analyze the National Education Policy 2009. For the second part, five teacher educators from public sector universities in Lahore were selected to get their reflection. For this purpose, a self developed semi-structured interview was used. Data was analyzed through coding and categorizing. Then different themes were generated from the categories. The findings of the study show that the most important feature of quality education is quality of the teachers. Policy provisions about the recruitment of teachers and curriculum of teacher education are positive steps to improve the quality of education. Teacher educators’ opinions were also strengthening the above findings. There is need to conduct research before planning the policy provisions. Anam Noshaba is a PhD scholar in Institute of Education and Research, University of the Punjab, Lahore, Pakistan. Her area of interest is Educational Leadership and Management.&nbsp

Influence of Socio-demographic Variables on Prevalence of Hypertension in Lahore Division, Pakistan

Hypertension is a growing public health issue at global level and it is considered as a potent factor for cardiovascular ailments. But various socio-demographic factors are root causes to provoke this physiological disorder. In current study, through cross sectional survey, performa based data of 100 persons was collected from cities Lahore division, Pakistan. The results showed that males are more suffering than females and fall in age range of 20-40yrs. Most frequently reported initial symptoms are fatigue, irregular heartbeat and difficulty in breathing. Whereas district wise comparison indicated higher prevalence level in Lahore and Kasur than Shiekhupura and Nankana Sahib.   Similarly, ANOVA results highlighted that economic status matters the most, parallel to the extent of awareness among masses, that’s why; mediocre is suffering more than upper or lower class. Thus cost effective treatments based findings should be our future goal to control this growing disease

Spontaneous intracranial hypotension; three case reports with similar clinical manifestations, treated successfully using different management techniques.

Spontaneous Intracranial hypotension (SIH) is a rare neurological disorder, characterized by orthostatic headaches. Due to the complicity of its diagnosis and lack of awareness amongst physicians, SIH remains an under-diagnosed disease and its true prevalence remains unknown. It is a reversible condition, if diagnosed early. Delay in diagnosis can result in life threatening complications.Case Reports:We present a case series of three patients who presented with typical symptoms of SIH. But management course of each patient varied. The first patient responded well to the EBP (epidural blood patch) while the second improved with conventional symptomatic treatment. The third patient needed a surgical intervention for complication developed due to SIH. This case series hence covers a variety of treatment options for patients with SIH.Conclusion:SIH is an emerging challenge for neurologists worldwide. Awareness amongst physicians regarding this disease along with a high level of suspicion and good history skills will allow early diagnosis of the disease and prevent delay in treatment and hence complications

Early Versus Interval Cholecystectomy in Mild Acute Biliary Pancreatitis. A Retrospective Study in Tertiary Care Hospital

Objective: The objective is to determine the adequacy of early cholecystectomy (EC) versus interval cholecystectomy (IC) in terms of recurrence, duration of hospital admission, and perioperative complications after mild acute biliary pancreatitis (MABP). Methodology: After endorsement from the ethical committee, clinical data and files of all the admitted patients having MABP in the general surgery department of Holy Family Hospital, Rawalpindi, was collected retrospectively from August 2017 to July 2020. The patients’ demographic profile, clinical findings, diagnostic investigations, timing of cholecystectomy, operating surgeons, operative time, biliary complications, intraoperative bleeding, conversion rate, duration of admission, and recurrence were reviewed. Patients presented with abdominal pain, vomiting, jaundice, or fever. The diagnosis was confirmed on the basis of a CT scan of the abdomen showing an inflamed pancreas and stones in the gallbladder. Outcomes were compared and reviewed between the two groups. Results: In this research proposal, 263 patients admitted were analyzed. EC was performed were discharged after conservative management and followed up after 12 weeks for interval laparoscopic cholecystectomy (IC). It was observed in patients of IC (EC 2 [1.2%] vs IC 7[7%]; p value <0.01) while duration of hospitalization was prolonged as compared to patients of EC (EC 5.53+0.58days vs IC 5.82+0.78days; p value <0.001). lar in both EC and IC. Conclusion: EC performed after MABP is associated with shorter duration of hospitalization and reduced recurrence with similar rate of perioperative complications