Analysis of Statistically Predicted Rate Constants for Pyrolysis of High-Density Plastic Using R Software

The surge in plastic waste production has forced researchers to work on practically feasible recovery processes. Pyrolysis is a promising and intriguing option for the recycling of plastic waste. Developing a model that simulates the pyrolysis of high-density polyethylene (HDPE) as the most common polymer is important in determining the impact of operational parameters on system behavior. The type and amount of primary products of pyrolysis, such as oil, gas, and waxes, can be predicted statistically using a multiple linear regression model (MLRM) in R software. To the best of our knowledge, the statistical estimation of kinetic rate constants for pyrolysis of high-density plastic through MLRM analysis using R software has never been reported in the literature. In this study, the temperature-dependent rate constants were fixed experimentally at 420 °C. The rate constants with differences of 0.02, 0.03, and 0.04 from empirically set values were analyzed for pyrolysis of HDPE using MLRM in R software. The added variable plots, scatter plots, and 3D plots demonstrated a good correlation between the dependent and predictor variables. The possible changes in the final products were also analyzed by applying a second-order differential equation solver (SODES) in MATLAB version R2020a. The outcomes of experimentally fixed-rate constants revealed an oil yield of 73% to 74%. The oil yield increased to 78% with a difference of 0.03 from the experimentally fixed rate constants, but light wax, heavy wax, and carbon black decreased. The increased oil and gas yield with reduced byproducts verifies the high significance of the conducted statistical analysis. The statistically predicted kinetic rate constants can be used to enhance the oil yield at an industrial scale.     

Zinc(ii) triazole meso-arylsubstituted porphyrins for UV-visible chloride and bromide detection. Adsorption and catalytic degradation of malachite green dye

Three new triazole meso-arylporphyrins (4a–c) were synthesized by the copper(i)-catalyzed azide alkyne cycloaddition (CuAAC) “click” reaction in high yield. The corresponding zinc(ii) coordination compounds (5a–c) have also been prepared. All 4a–c and 5a–c porphyrin species were fully characterized by elemental analysis, electrospray ionization and MALDI-TOF mass spectrometry, infrared spectroscopy, proton nuclear magnetic resonance, UV-visible, fluorescence and cyclic voltammetry. The zinc(ii) 5a–c complexes have been tested as detectors for Cl⁻ and Br⁻ anions. UV-visible titrations reveal that these host systems exhibit strong anion binding affinities. The efficiency of the adsorption of the malachite green dye (MG) dye on the 4a–c free base porphyrins and the corresponding zinc(ii) complexes 5a–c was investigated by a kinetic study using these synthetic porphyrin derivatives as adsorbents. The use of our triazole Zn(ii) complexes in the catalytic degradation of the MG dye is the first example where a metalloporphyrin is involved in the MG dye decolorization reaction. The degradation reactions were carried out using an ecological oxidant (H₂O₂), where the efficiency of the decolorization has been characterized by UV-visible spectroscopic analysis. Several factors affecting the degradation phenomenon have been studied. The energetic parameters concerning the degradation process have also been determined.

Three triazole porphyrins and there corresponding zinc complexes are described as well as their spectroscopic and electrochemical data. The chloride and bromide sensing efficiency and the degradation of the malachite green dye are also reported.     

In situ instrumented posterolateral fusion without decompression in symptomatic low-grade isthmic spondylolisthesis in adults

Forty patients with an average age of 26.5 years were treated for symptomatic low-grade isthmic spondylolisthesis with in situ instrumented posterolateral fusion. All patients had failed previous conservative treatment. Average follow-up was 42.2 months (range: 30-62 months). Low-back pain resolved in 70% of the patients, whereas 65% of those with radicular pain reported complete resolution of the symptoms. At the final follow-up 82.5% of the patients had improvement in their function. Solid fusion was achieved in 70% of the patients. It was uncertain in 10% and a fusion failure was seen in 20%. The anterior slippage as measured by the Taillard method was 31.55% and an average 35% correction was seen after surgery. However, an average 10% loss of correction was seen at the final evaluation. The clinical results were evaluated by Kim and Kim criteria. Satisfactory results were obtained in 65% of patients and this was closely associated with the rate of successful fusion. The results suggest that clinical outcome is closely related to the attainment of solid fusion and decompression or removal of the loose laminar fragment seems unnecessary in patients without major neurological symptoms.     

A revised classification of the cleft lip and palate

BACKGROUND:

Submucous cleft palate is characterized by muscular diastasis of the velum in the presence of intact mucosa with variable combinations of bifid uvula and hard palatal defect. Submucous cleft palate is indicated as a separate entity in most previous classifications but it has never been properly classified on an anatomical basis.

OBJECTIVES:

To revise the Smith-modified Kernahan ‘Y’ classification of cleft lip and palate deformities, and to describe the different anatomical subtypes of submucous cleft palate.

METHODS:

The present study was conducted in Hayatabad Medical Complex, Abasin Hospital and Aman Hospital Peshawar, Pakistan, from November 2010 to December 2011. All patients who presented to the outpatient departments with cleft lip and palate, with the exception of previously operated cases, were included. All cases were described according to the Smith-modified Kernahan ‘Y’ classification and the authors’ revised Smith-modified Kernahan ‘Y’ classification. All of the data were organized and analyzed using SPSS version 17 (IBM Corporation, USA).

RESULTS:

A total of 163 cases of cleft lip and palate deformities were studied, of which 59.5% were male and 40.5% were female. Smith modification of the Kernahan ‘Y’ classification completely described the cleft deformities in 93.9% of patients. However, while the Kernahan ‘Y’ classification represented the submucous cleft palate, it did not describe its different anatomical subtypes in 6.13% of patients. The revised Smith-modified Kernahan ‘Y’ classification completely described the cleft deformities of the entire study population, including the different submucous cleft palate patients.

DISCUSSION:

The Smith alphanumeric modification of the Kernahan ‘Y’ classification of cleft lip and palate came into existence after a long search and a series of modifications over the past century. This classification system describes the cleft region, site of the cleft, degree of the cleft, rare and asymmetrical clefts, and are computer database friendly. However, this classification did not describe the different anatomical subtypes of submucous cleft palate that have variable relationships with velopharyngeal insufficiency.

CONCLUSION:

The revised Smith-modified Kernahan ‘Y’ classification described in the present study can describe all types of cleft lip and palate deformities in addition to the different types of submucous cleft palate deformities.     

Long-term immunogenicity and efficacy of a 9-valent conjugate pneumococcal vaccine in human immunodeficient virus infected and non-infected children in the absence of a booster dose of vaccine

The long-term immunogenicity and vaccine efficacy (VE) of a 9-valent conjugate pneumococcal vaccine was studied in HIV infected and HIV non-infected children. VE against vaccine-serotype invasive pneumococcal disease following 6.16 years of follow-up persisted in HIV non-infected children (77.8%; 95% CI 34.4-92.5 compared to 83% after 2.3 years of follow-up), and declined from 65% to 38.8% (95% CI -7.8 to 65.2) in HIV infected children. HIV non-infected vaccinees had equal (serotypes 4, 6B, 14, 19F) or greater (serotypes 9V, 18C, 23F) proportions of serotype-specific antibody concentrations of > or =0.2microg/ml to vaccine-serotypes analyzed compared to HIV infected vaccinees at 5.3 years of age.     

The Latest Evolution of the Medtronic CoreValve System in the Era of Transcatheter Aortic Valve Replacement: Matched Comparison of the Evolut PRO and Evolut R

Objectives

The aim of this study was to investigate the hemodynamic and clinical performance of the Evolut PRO compared with its direct predecessor, the Evolut R.

No Evidence for Association of β‐Defensin Genomic Copy Number with HIV Susceptibility,HIV Load during Clinical Latency,or Progression to AIDS

Common single‐nucleotide variation in the host accounts for 25% of the variability in the plasma levels of HIV during the clinical latency stage (viral load set point). However, the role of rare variants and copy number variants remains relatively unexplored. Previous work has suggested copy number variation of a cluster of β‐defensin genes affects HIV load in treatment‐naïve sub‐Saharan Africans and rate of response to antiretroviral treatment. Here we analyse a total of 1827 individuals from two cohorts of HIV‐infected individuals from Europe and sub‐Saharan Africa to investigate the role of β‐defensin copy number variation on HIV load at set point. We find no evidence for association of copy number with viral load. We also compare distribution of β‐defensin copy number between European cases and controls and find no differences, arguing against a role of β‐defensin copy number in HIV acquisition. Taken together, our data argue against an effect of copy number variation of the β‐defensin region in the spontaneous control of HIV infection.     

Characteristics and comparisons of acute stroke in “recovered" to “active COVID-19 and “pre-pandemic” in Qatar database

Journal of Thrombosis and Thrombolysis - Understanding the relationship of COVID-19 to stroke is important. We compare characteristics of pre-pandemic stroke (PPS), cases in acute COVID infection...     

Melatonin as a Topical/Systemic Formulation for the Management of Periodontitis: A Systematic Review

Objectives: To qualitatively and quantitatively review the use of melatonin as a topical/systemic formulation for the management of periodontitis. Materials and methods: PubMed; Scopus; and Web of Science databases were searched using the MesH terms “melatonin” and “periodontitis”. Title and abstracts were screened to eliminate irrelevant and duplicate articles. The full text data of the screened articles were assessed using the selection criteria. Results: Of 176 identified articles (PubMed-66; Scopus-56; Web of Science-52; Cross-reference-2), only 12 studies qualified to be included in the systematic review. Four studies assessed the independent effect of 1% topical melatonin formulation while 8 articles assessed the adjunctive use of systemic melatonin formulation (1–10 mg) following scaling and root planing (SRP). All studies showed an improvement in periodontal parameters such as pocket depth, clinical attachment loss, periodontal disease index, community periodontal index, gingival bleeding scores, and prognostic marker levels in saliva and serum. A meta-analysis of data from 2 studies revealed that 1–2 mg (systemic) melatonin supplementation reduced pocket depth; although the difference was not statistically significant and hence cannot be interpreted or used for conclusive evidence. Risk of Bias Assessment tool (RoBANS) and Cochrane Collaboration RoB tool elicited a high risk of bias in the included studies. GRADE (recommendation assessment, development, and evaluation) inferred a weak recommendation for the use of melatonin in periodontitis management. Conclusions: Melatonin supplementation (topical and systemic) in periodontitis patients improved key periodontal parameters including pocket depth and clinical attachment loss. Clinical relevance: Melatonin could be a potential host modulatory agent for periodontitis management; although the data from the present review should be interpreted carefully due to the associated high risk of bias.