Assessing mental health among students in the UAE: A cross-sectional study utilizing the DASS-21 scale.

Background: The escalating worldwide concerns for mental health, significantly amplified by the COVID-19 pandemic, necessitates understanding the impact on vulnerable populations, such as university students. This study aims to investigate the prevalence and implications of depression, anxiety, and stress among university students in the United Arab Emirates (UAE) using the Depression, Anxiety, and Stress Scale-21 Items (DASS-21). Methods: This study utilized convenience sampling to investigate the mental health of undergraduates in UAE universities using a bilingual DASS-21 questionnaire via Google Forms. Analysis was conducted using SPSS version 29.0, employing descriptive statistics, Chi-squared tests, Mann-Whitney tests, Kruskal-Wallis tests, and Multinomial Logistic Regression to analyze relationships between sociodemographic variables and mental health scores. Results: The study examined 332 students, with most female participants (81 %, n = 269) and individuals aged 18-20 (89.8 %, n = 298). It revealed higher mean DASS scores among females: Depression (M = 15.80, p = 0.030), Anxiety (M = 17.63, p < 0.001), and Stress (M = 22.61, p < 0.001). Fourth-year students exhibited the highest DASS scores for depression (M = 30.33, p = 0.002), anxiety (M = 21.33, p = 0.002), and stress (M = 27.00, p = 0.005). Younger participants aged 18-20 had an odds ratio (OR) of 4.925 for depression, indicating they were approximately five times more likely to experience depression. Conclusions: This study reveals gender, age, and academic-year variations in depression, anxiety, and stress among UAE university students. Specifically, our findings indicate higher levels of anxiety and stress among females and reveal academic-year and age-related patterns in mental health conditions. University support services in the UAE should better address student needs, including counseling focused on high school to university transition challenges.

Screening and Determination of Synthetic PDE-5 Inhibitors in Adulterated Sexual Enhancement Supplements.

This paper reports an important investigation and quantification of adulteration of sexual enhancement supplements with prescription medicines available in United Arab Emirates (UAE): tadalafil, sildenafil and vardenafil. A total of 158 sexual enhancement supplements were collected and analyzed in the current study. The samples were screened using REVERSE-phase liquid chromatography tandem high-resolution mass spectrometry/mass spectrometry (RP-HPLC-MS/MS). Of all sexual enhancements, 12.7% (95% CI: 7.4-18) contained undeclared sildenafil, 3.8% (95% CI: 0.78-6.81) contained undeclared tadalafil and 1.9% (95% CI: 0.25-4.05) contained undeclared vardenafil. Of all sexual enhancement supplements, 13.9% (95% CI: 8.5-19.4) contained significant concentrations of sildenafil, tadalafil or vardenafil. While the study found relatively low levels of undeclared pharmaceutical ingredients in the sexual enhancement dietary supplements available on the UAE market, it is likely that patients with ED tend to consume multiple such supplements daily, thereby exposing themselves to highly elevated cumulative levels.

Rosmanol Triggers Apoptosis Against MNNG-induced Gastric Carcinogenesis in Rats through Attenuation of the P13K/AKT/HMBG1 Signaling Pathway.

BACKGROUND: Gastric cancer (GC) is a frequent malignant neoplasm found in China. Despite numerous therapeutic methodologies to ameliorate the well-being of GC patients, their efficiency remains inadequate. OBJECTIVE: Rosmanol (RML) is a phenolic diterpene compound with antioxidant and anticancer activities. In the current research, the apoptotic efficacy of RML on methylnitronitrosoguanidine (MNNG)-induced GC model was determined. MATERIALS AND METHODS: The rats were allocated into four sets, viz., normal control, MNNG (200 mg/kg bw) + NaCl, MNNG + RML (20 mg/kg), and RML (20 mg/kg) orally treated for 20 weeks. RESULTS: The results exposed that GC rats revealed higher (P<0.05) levels of TBARS and reduced antioxidant status in the stomach and liver tissues counter to other groups. In contrast, the TBARS level was substantially alleviated (P<0.05) and restored the antioxidant status in RMLadministered rats. Histopathologic assessment of gastric tissue unveiled that an MNNG-induced group presented squamous cell carcinoma with keratin pearls. The administration of RML reduced GC incidence, and only mild dysplasia was observed. Further, RML alleviated Bcl-2, P13K, AKT, and HMGB1, as evidenced by RT-PCR and Western blot analysis. CONCLUSION: Furthermore, RML triggered caspase-mediated mitochondrial apoptosis through the inactivation of the PI3K/AKT/HMGB1 pathway, eventually leading to GC cell death. This highlights that RML may be a potential natural antioxidant employed as a chemoprotective agent in GC rats.

Community pharmacist-led point-of-care eGFR screening: early detection of chronic kidney disease in high-risk patients.

Adherence to scheduled physician screenings for renal function monitoring in patients with chronic kidney disease (CKD) or those at high risk remains suboptimal despite the endorsement of regular screenings by several clinical practice guidelines. Our study aims to assess the effectiveness of a point-of-care CKD screening program led by these pharmacists using the PICCOLO device while recognizing the unique position of community pharmacists in primary care. We conducted an 11-month prospective point-of-care interventional research study in the United Arab Emirates to evaluate the performance of a community pharmacist-led CKD screening program for high-risk patients. Six diverse community pharmacies were selected based on staff availability, patient volume, and their offered range of services. Eligible individuals with risk factors for CKD were identified during medication evaluations. The PICCOLO Comprehensive Metabolic Panel facilitated on-site blood analysis, delivering estimated Glomerular Filtration Rate (eGFR) results within 10 to 15 min. Data also included eGFR categories, demographic information, and insights into lifestyle and health habits collected through a questionnaire. Pharmacists conducted comprehensive medication reviews and offered referrals and lifestyle guidance as part of the program. The study encompassed a total of 400 patients, with an average age of 69 ± 13.4 years within the study cohort. Notably, 38.8% (155 individuals) of the 400 patients were found to have undiagnosed CKD stages 3-5. Univariate logistic regression analysis revealed a significant association between a higher incidence of CKD stages 3-5 and factors such as older age, a history of hypertension, vascular disease, and diabetes mellitus. In the multivariate regression model, age and a history of diabetes mellitus emerged as significant predictors of an elevated risk of CKD. This study sheds light on the viability and impact of CKD screening programs conducted by community pharmacists, particularly in detecting CKD stages 3-5. The findings have implications for healthcare policies, as they can influence the enhancement of early detection and management of CKD. Moreover, these insights may catalyze focused screening initiatives and strengthen collaboration between community pharmacies and healthcare systems to benefit patients at high risk of CKD.

Detecting manuscripts written by generative AI and AI-assisted technologies in the field of pharmacy practice.

Generative AI can be a powerful research tool, but researchers must employ it ethically and transparently. This commentary addresses how the editors of pharmacy practice journals can identify manuscripts generated by generative AI and AI-assisted technologies. Editors and reviewers must stay well-informed about developments in AI technologies to effectively recognise AI-written papers. Editors should safeguard the reliability of journal publishing and sustain industry standards for pharmacy practice by implementing the crucial strategies outlined in this editorial. Although obstacles, including ignorance, time constraints, and protean AI strategies, might hinder detection efforts, several facilitators can help overcome those obstacles. Pharmacy practice journal editors and reviewers would benefit from educational programmes, collaborations with AI experts, and sophisticated plagiarism-detection techniques geared toward accurately identifying AI-generated text. Academics and practitioners can further uphold the integrity of published research through transparent reporting and ethical standards. Pharmacy practice journal staffs can sustain academic rigour and guarantee the validity of scholarly work by recognising and addressing the relevant barriers and utilising the proper enablers. Navigating the changing world of AI-generated content and preserving standards of excellence in pharmaceutical research and practice requires a proactive strategy of constant learning and community participation.

Enhancing photodynamic therapy efficacy through silica nanoparticle-mediated delivery of temoporfin for targeted in vitro breast cancer treatment.

Photodynamic therapy (PDT), an approach to cancer treatment, relies fundamentally on two key elements: a light source and a photosensitizing agent. A primary challenge in PDT is the efficient delivery of photosensitizers to the target tissue, hindered by the body's reticuloendothelial system (RES). Silica nanoparticles (SiNPs), known for their unique properties, emerge as ideal carriers in this context. In this study, SiNPs are utilized to encapsulate Temoporfin, a photosensitizer, aiming to enhance its delivery and reduce toxicity, particularly for treating MCF-7 cancer cells in vitro. The synthesized SiNPs were meticulously characterized by their size and shape using Transmission Electron Microscopy (TEM). The study also involved evaluating the cytotoxicity of both encapsulated and naked Temoporfin across various concentrations. The objective was to determine the ideal concentration and exposure duration using red laser light (intensity approximately 110 mW/cm2) to effectively eradicate MCF-7 cells. The findings revealed that Temoporfin, when encapsulated in SiNPs, demonstrated significantly greater effectiveness compared to its naked form, with notable improvements in concentration efficiency (50 %) and exposure time efficiency (76.6 %). This research not only confirms the superior effectiveness of encapsulated Temoporfin in eliminating cancer cells but also highlights the potential of SiNPs as an efficient drug delivery system in photodynamic therapy. This sets the groundwork for more advanced strategies in cancer treatment.

Advanced Optoelectronic Modeling and Optimization of HTL-Free FASnI3/C60 Perovskite Solar Cell Architecture for Superior Performance.

In this study, a novel perovskite solar cell (PSC) architecture is presented that utilizes an HTL-free configuration with formamide tin iodide (FASnI3) as the active layer and fullerene (C60) as the electron transport layer (ETL), which represents a pioneering approach within the field. The elimination of hole transport layers (HTLs) reduces complexity and cost in PSC heterojunction structures, resulting in a simplified and more cost-effective PSC structure. In this context, an HTL-free tin HC(NH2)2SnI3-based PSC was simulated using the solar cell capacitance simulator (SCAPS) within a one-dimensional framework. Through this approach, the device performance of this novel HTL-free FASnI3-based PSC structure was engineered and evaluated. Key performance parameters, including the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), power conversion efficiency (PCE), I-V characteristics, and quantum efficiency (QE), were systematically assessed through the modulation of physical parameters across various layers of the device. A preliminary analysis indicated that the HTL-free configuration exhibited improved I-V characteristics, with a PCE increase of 1.93% over the HTL configuration due to improved electron and hole extraction characteristics, reduced current leakage at the back contact, and reduced trap-induced interfacial recombination. An additional boost to the device's key performance parameters has been achieved through the further optimization of several physical parameters, such as active layer thickness, bulk and interface defects, ETL thickness, carrier concentration, and back-contact materials. For instance, increasing the thickness of the active layer PSC up to 1500 nm revealed enhanced PV performance parameters; however, further increases in thickness have resulted in performance saturation due to an increased rate of hole-electron recombination. Moreover, a comprehensive correlation study has been conducted to determine the optimum thickness and donor doping level for the C60-ETL layer in the range of 10-200 nm and 1012-1019 cm-3, respectively. Optimum device performance was observed at an ETL-C60 ultra-thin thickness of 10 nm and a carrier concentration of 1019 cm-3. To maintain improved PCEs, bulk and interface defects must be less than 1016 cm-3 and 1015 cm-3, respectively. Additional device performance improvement was achieved with a back-contact work function of 5 eV. The optimized HTL-free FASnI3 structure demonstrated exceptional photovoltaic performance with a PCE of 19.63%, Voc of 0.87 V, Jsc of 27.86 mA/cm2, and FF of 81%. These findings highlight the potential for highly efficient photovoltaic (PV) technology solutions based on lead-free perovskite solar cell (PSC) structures that contribute to environmental remediation and cost-effectiveness.

Assessing Students' Knowledge and Attitudes Regarding the Risks and Prevention of Consanguineous Marriage: A Cross-Sectional Online Survey.

Background: Several studies indicate a correlation between consanguinity and genetic disorders, congenital malformations, harm to reproductive health, and increased child mortality. Objective: To assess students' knowledge and attitudes about risks and prevention of consanguineous marriage. Methods: Demographic details of the participants and data on knowledge and attitudes concerning the risks and prevention of consanguineous marriage were obtained using an online self-administered questionnaire. The factors associated with good knowledge and attitude toward consanguineous marriage were investigated by logistic regression analysis. Results: A total of 667 participants enrolled in the study. The average knowledge score about consanguineous marriage risk and prevention was 78.6% with a 95% confidence interval (CI) [77.3, 79.8], and the average attitude was 79.7% with a 95% confidence interval (CI) [79, 80.6]. A better knowledge score was observed in older participants (OR 1.01; 95% CI 1.004-1.024), females (OR 1.69; 95% CI 1.48-1.94), participants with parental history of consanguinity (OR 1.33; 95% CI 1.17-1.52), participants with family history of consanguineous marriage (OR 5.18; 95% CI 2.19-7.10), and participants with family history of inherited disease (OR 1.52; 95% CI 1.25-1.86). Conclusion: In general, the overall level of knowledge and attitudes toward consanguineous marriage risk and prevention was good among university students. To efficiently control and manage the adverse health impacts associated with consanguineous marriage, there is an urgent need to develop and implement evidence-based counseling and screening programs for consanguineous marriage that would significantly reduce the number of at-risk marriages.

Photocatalytic degradation of aqueous methylene blue using ca-alginate supported ZnO nanoparticles: point of zero charge role in adsorption and photodegradation.

A novel insoluble Ca-Alginate created from soluble Na-Alginate was used as a support substrate for ZnO nanoparticles producing ZnO@Ca-Alginate composite photocatalyst. Fourier Transform Infrared (FT-IR), Ultraviolet-Visible (UV-Vis), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), and X-ray Diffraction (XRD) analysis techniques were used in the characterization of the prepared ZnO@Ca-Alginate. The ZnO@Ca-Alginate was tested for its potential use in the photodegradation of Methylene Blue (MB) from an aqueous solution under solar-simulated light. This composite photocatalyst efficiency in MB removal was compared with naked ZnO potential considering different conditions and parameters (e.g. pH, MB concentration, amount of photocatalyst, and irradiation time). The MB concentrations were identified using UV-vis spectrophotometric methods. While, high-performance liquid chromatography (HPLC), Total organic carbon (TOC) analysis, and other elemental analyses were used to confirm the MB complete mineralization. The MB photodegradation results were performed by using UV-vis analysis., the results showed that up to 95% of MB (40 mL, 40 ppm) was removed within 30 min of irradiation using either ZnO@Ca-Alginate or naked ZnO. The pH and the zero-charge point (Pzc) values play a main role in the adsorption and photodegradation results. The Pzc values for Ca-Alginate, ZnO, and Zn@Ca-Alginate were 6.5, 8.8, and 6.8 respectively. The prepared composite catalyst showed a maximum adsorption and photodegradation in a basic to slightly basic medium, the MB completely removed at pH of 7.7 within an hour of irradiation. The complete miniralzation of MB at the end of the photodegrdation process was confirmed. Here it is proved that the ZnO@Ca-Alginate photocatalyst can be recovered and reused without any significant decrease in its effectiveness.

Risk Awareness and Demographic Characteristics Associated With the Use of Sexual Enhancement Supplements Among University Staff: A Cross-Sectional Study in the United Arab Emirates.

Sexual enhancement supplements (SESs) that have illegal additions of pharmaceuticals or analogues pose a significant health risk, particularly with long-term usage. When supplements are adulterated with phosphodiesterase type 5 (PDE-5) inhibitors, dosages can vary widely and there may be an increase in adverse effects and drug-drug interactions which cannot be avoided. Consequently, there is a need to evaluate the public risk awareness toward SES and the associated adverse events as well as explore significant factors associated with knowledge and risk awareness. A cross-sectional community-based study was conducted among University male students and staff at Ajman University, United Arab Emirates (UAE), using a self-administered survey via a web-based electronic link to explore key issues. A total of 1,101 male subjects participated in the study and completed the questionnaire. Four hundred and thirty-three(39.3%) (95% confidence interval [CI]: 33.2-44.5) participants reported using SES products. Of these, 137 (31.6%) [95% CI: 28.6-37.2] experienced adverse effects from SES product use. SES use was more prevalent among participants aged 60 to 69 years (odds ratio [OR]: 2.94; 95% CI: 1.63-5.28), diabetic patients (OR: 2.61; 95% CI: 1.75-3.90), hypertension patients (OR: 2.12; 95% CI: 1.45-3.1), and those overweight or obese (OR: 1.84; 95% CI: 1.44-2.35). This study indicates that SES is a popular practice among the UAE university staff and students. However, there is a need to implement risk awareness programs to raise public awareness regarding SES use and safety. Regulatory bodies are encouraged to provide additional advice on the proper use and possible risks of consuming SES.

Detection of Virus SARS-CoV-2 Using a Surface Plasmon Resonance Device Based on BiFeO3-Graphene Layers.

Coronavirus disease (COVID-19) pandemic outbreak is being investigated by severe respirational syndrome coronavirus-2 (SARS-CoV-2) as a global health issue. It is crucial to propose sensitive and rapid coronavirus detectors. Herein, we propose a biosensor based on surface plasmon resonance (SPRE) for the detection of SARS-CoV-2 virus. To achieve improved sensitivity, a BiFeO3 layer is inserted between a metal (Ag) thin film and a graphene layer in the proposed SPRE device so that it has the structure BK7 prism/ Ag/ BiFeO3/ graphene/ analyte. It has been demonstrated that a small variation in the refractive index of the analyte can cause a considerable shift in the resonance angle caused by the remarkable dielectric properties of the BiFeO3 layer, which include a high index of refraction and low loss. The proposed device has shown an extremely high sensitivity of 293 deg/RIU by optimizing the thicknesses of Ag, BiFeO3, and the number of graphene sheets. The proposed SPRE-based sensor is encouraging for use in various sectors of biosensing because of its high sensitivity.

Structural, Optical, and Electrical Investigations of Nd2O3-Doped PVA/PVP Polymeric Composites for Electronic and Optoelectronic Applications.

In this present work, a PVA/PVP-blend polymer was doped with various concentrations of neodymium oxide (PB-Nd+3) composite films using the solution casting technique. X-ray diffraction (XRD) analysis was used to investigate the composite structure and proved the semi-crystallinity of the pure PVA/PVP polymeric sample. Furthermore, Fourier transform infrared (FT-IR) analysis, a chemical-structure tool, illustrated a significant interaction of PB-Nd+3 elements in the polymeric blends. The transmittance data reached 88% for the host PVA/PVP blend matrix, while the absorption increased with the high dopant quantities of PB-Nd+3. The absorption spectrum fitting (ASF) and Tauc's models optically estimated the direct and indirect energy bandgaps, where the addition of PB-Nd+3 concentrations resulted in a drop in the energy bandgap values. A remarkably higher quantity of Urbach energy for the investigated composite films was observed with the increase in the PB-Nd+3 contents. Moreover, seven theoretical equations were utilized, in this current research, to indicate the correlation between the refractive index and the energy bandgap. The indirect bandgaps for the proposed composites were evaluated to be in the range of 5.6 eV to 4.82 eV; in addition, the direct energy gaps decreased from 6.09 eV to 5.83 eV as the dopant ratios increased. The nonlinear optical parameters were influenced by adding PB-Nd+3, which tended to increase the values. The PB-Nd+3 composite films enhanced the optical limiting effects and offered a cut-off laser in the visible region. The real and imaginary parts of the dielectric permittivity of the blend polymer embedded in PB-Nd+3 increased in the low-frequency region. The AC conductivity and nonlinear I-V characteristics were augmented with the doping level of PB-Nd+3 contents in the blended PVA/PVP polymer. The outstanding findings regarding the structural, electrical, optical, and dielectric performance of the proposed materials show that the new PB-Nd+3-doped PVA/PVP composite polymeric films are applicable in optoelectronics, cut-off lasers, and electrical devices.

Acceptability and Willingness of UAE Residents to Use OTC Vending Machines to Deliver Self-Testing Kits for COVID-19 and the Implications.

Purpose: Self-testing kits for SARS-CoV-2 appear effective, practical, safe and reliable as well as helping patients with mild-to-moderate symptoms to be successfully managed at home without going to hospital. As a result, ease pressures on hospitals. OTC vending machines offer the potential for SARS-CoV-2 self-testing kits alongside making available OTC treatments to alleviate the symptoms of COVID-19. As a result, providing confidentiality alongside ease of use in case people do not want their status broad casted. Consequently, there was a need to assess the acceptability and willingness regarding the availability of OTC vending machines to dispense self-testing kits for SARS-CoV-2 among UAE residents to provide future direction. Patients and Methods: A cross-sectional survey using a designed questionnaire was based on previous research and expert input and pilot tested. All items in the final questionnaire were seen as acceptable with a satisfactory content validity. A purposive sampling strategy was used in the principal study by primarily sending a link to the questionnaire to UAE universities via Facebook and WhatsApp. Results: A total of 876 respondents participated in the study and completed the whole questionnaire. Most participants were female (63%), Arabic origin (42%) and holding a bachelor's degree (84.5%). There was high acceptability and willingness to use self-testing kits (87.2%), with 88.6% of respondents believing OTC vending machines would be beneficial for patients with actual or suspected SARS-CoV-2. Gender, nationality, educational level, employment status, having relatives infected with SARS-CoV-2 and being vaccinated were significantly associated with attitudes towards the self-testing kits. Recognised barriers include their potential costs, ease of access and help for those who cannot read the instructions. Conclusion: Overall, there was high acceptability and willingness to use OTC vending machines to deliver self-testing kits for SARS-CoV-2 among the surveyed participants. Key barriers will need to be addressed to enhance their use.

Ionization Radiation Shielding Effectiveness of Lead Acetate, Lead Nitrate, and Bismuth Nitrate-Doped Zinc Oxide Nanorods Thin Films: A Comparative Evaluation.

The fabrication of Nano-based shielding materials is an advancing research area in material sciences and nanotechnology. Although bulky lead-based products remain the primary choice for radiation protection, environmental disadvantages and high toxicity limit their potentials, necessitating less costly, compatible, eco-friendly, and light-weight alternatives. The theme of the presented investigation is to compare the ionization radiation shielding potentialities of the lead acetate (LA), lead nitrate (LN), and bismuth nitrate (BN)-doped zinc oxide nanorods-based thin films (ZONRs-TFs) produced via the chemical bath deposition (CBD) technique. The impact of the selected materials' doping content on morphological and structural properties of ZONRs-TF was investigated. The X-ray diffractometer (XRD) analyses of both undoped and doped TFs revealed the existence of hexagonal quartzite crystal structures. The composition analysis by energy dispersive (EDX) detected the corrected elemental compositions of the deposited films. Field emission scanning electronic microscope (FESEM) images of the TFs showed highly porous and irregular surface morphologies of the randomly aligned NRs with cracks and voids. The undoped and 2 wt.% BN-doped TFs showed the smallest and largest grain size of 10.44 nm and 38.98 nm, respectively. The linear attenuation coefficient (µ) values of all the optimally doped ZONRs-TFs measured against the X-ray photon irradiation disclosed their excrement shielding potency. The measured µ values of the ZONRs-TFs displayed the trend of 1 wt.% LA-doped TF > 1 wt.% LN-doped TF > 3 wt.% BN-doped TF > undoped TFs). The values of µ of the ZONRs-TFs can be customized by adjusting the doping contents, which in turn controls the thickness and morphology of the TFs. In short, the proposed new types of the LA-, LN- and BN-doped ZONRs-TFs may contribute towards the development of the prospective ionization radiation shielding materials.

Photocatalytic degradation of phenazopyridine contaminant in soil with direct solar light.

Photocatalytic degradation of waste pharmaceutics, with solar radiation, is described here as a feasible method to purify pre-contaminated soils. Phenazopyridine has been used as a model soil contaminant. Two different nano-size powders have been first examined as catalysts, namely commercial TiO2 (anatase) and commercial ZnO. As the ZnO showed higher catalytic efficiency, the study was then focused on it. The commercial ZnO powder was then compared with lab-prepared ZnO powder, and the latter shows relatively higher efficiency. The ZnO was used in two different ways. In one way, dry ZnO catalyst powder was spread onto the soil, while in the other way the ZnO was sprayed onto the soil surface by a wet spray method. The spray technique shows slightly higher efficiency, in addition to being easier to apply at future large scale. Depending on conditions and type of photocatalyst used, up to 90% contaminant removal can be achieved in 30 min. In case of photocatalysis experiments, the reacted contaminant molecules undergo complete degradation with no detectable side reaction organic products. Possible evaporation or escape of organic contaminant, or other possibly resulting organics, is ruled out by a series of control experiments. Photodegradation process takes place only at the catalytic sites on the soil surface, where contaminant molecules that diffuse from the soil bulk are completely degraded. Other useful organisms inside the soil are not affected as they are kept away from catalyst sites. A plausible mechanism is proposed for the degradation process.