Prevalence of hepatitis B and associated factors in the Buea Regional Hospital, Cameroon

Introduction

Hepatitis B infection is a serious global health problem worldwide. In Cameroon, this infection shows a great variability in prevalence in the country and even within different population groups. However, the prevalence of HBV in the southwestern region is not yet known.

Objectives

This study was conducted to determine the prevalence of hepatitis B, its associated factors, and the patient's knowledge about the infection at the Buea Regional Hospital.

Method

We conducted a hospital-based cross-sectional study from March 29th to June 30th, 2021 involving participants of both sexes with ages ranging from 13 to 60+. A random sampling method was used to obtain a sample size of 113 participants as calculated using Lorentz's formula. The study questionnaires were administered to participants and their blood samples were collected by venous puncture. The blood samples were collected in non-hepainized test tube at the collection units of the Hospital. Diaspot one-step Hepatitis B Surface Antigen test strips with 99% sensitivity and 97% specificity were used to determine the status of the participants. The data were analysed using SPSS 25.0. Bivariate and multivariable analyses were used to obtain associated factors. The level of significance was set at p ≤ 0.05.

Results

A total of 125 participants were recruited. However, only 119 provided complete data (questionnaire and blood samples). A proportion 61 (51.3%) of the participants were females in the 20-29-year age group. The prevalence of hepatitis was 8.4%. Fifty-three percent (64) of the participants had adequate knowledge of Hepatitis B. Having had more than one sexual partner in the last six months and having visited a dentist in the past was significantly associated with Hepatitis B positive status (p ≤ 0.05).

Conclusion

The prevalence of Hepatitis B in the Buea Regional Hospital is 8.4% and 53.8% of the participants had adequate knowledge of the infection. Males were found to be 13.17 times more likely to be positive for Hepatitis B infection than females.

Physicochemical characterization of biological and synthetic forms of two lipid A-based TLR4 agonists

Toll-like receptor (TLR) agonists are recognized as potential immune-enhancing adjuvants and are included in several licensed vaccines. Monophosphoryl lipid A (MPL®, GlaxoSmithKline) is one such TLR4 agonist that has been approved for use in human vaccines, such as Cervarix and Shingrix. Due to the heterogeneous nature of biologically derived MPL and the need for safer and more potent adjuvants, our groups have developed the novel TLR4 agonist candidates, BECC438 and BECC470 using the Bacterial Enzymatic Combinatorial Chemistry (BECC) platform. BECC438 and BECC470 have been included in studies to test their adjuvant potential and found to be effective in vaccines against both viral and bacterial disease agents. Here, we report detailed biophysical characterization of BECC438 and BECC470 purified from a biological source (BECC438b and BECC470b, respectively) and synthesized chemically (BECC438s and BECC470s, respectively). Both BECC438s and BECC470s have identical acyl chain configurations, BECC438s is bis-phosphorylated and BECC470s is mono-phosphorylated with the removal of the 4' phosphate moiety. We determined the phase transition temperatures for the acyl chains of BECC438b and BECC470b and found them to be different from those exhibited by their synthetic counterparts. Furthermore, the phosphate groups of BECC438b and BECC470b are more highly hydrated than are those of BECC438s and BECC470s. In addition to exploring the BECC molecules' biophysical features in aqueous solution, we explored potential formulation of BECC438 and BECC470 with the aluminum-based adjuvant Alhydrogel and as part of an oil-in-water emulsion (Medimmune Emulsion or ME). All of the lipid A analogues could be fully absorbed to Alhydrogel or incorporated onto ME. Surprisingly, the BECC470s molecule, unlike the others, displayed a nearly baseline signal when monitored using a Limulus amebocyte lysate (LAL) endotoxin detection system. Despite this, it was shown to behave as an agonist for human and mouse TLR4 when tested using multiple cell-based systems. This work paves the way for further formulation optimization of two chemically defined TLR4 agonists that are showing great promise as vaccine adjuvants.

Characterization of Novel Amylase-Sensitive, Anti-Listerial Class IId Bacteriocin, Agilicin C7 Produced by Ligilactobacillus agilis C7

Among various biological agents, bacteriocins are important candidates to control Listeria monocytogenes which is a foodborne pathogen. In this study, a novel bacteriocin, named agilicin C7, was isolated from Ligilactobacillus agilis C7 showing inhibitory activity against L. monocytogenes. Agilicin C7 biosynthesis gene was characterized by bioinformatics analyses and heterologously expressed in Escherichia coli for further study. The anti-listeria activity of recombinant agilicin C7 (r-agilicin C7) was lost by proteases and α-amylase, suggesting that agilicin C7 is a glycoprotein. r-Agilicin C7 has wide pH and thermal stability and is also stable in various organic solvents. It destroyed L. monocytogenes by damaging the integrity of the cell envelope. These properties of r-agilicin C7 indicate that agilicin C7 is a novel amylase-sensitive anti-listerial Class IId bacteriocin. Physicochemical stability and inhibitory activity against L. monocytogenes of r-agilicin C7 suggest that it can be applied to control L. monocytogenes in the food industry, including dairy and meat products.

Squawks as an important physical finding for differentiation of diffuse panbronchiolitis from asthma in children: A case report

Diffuse panbronchiolitis (DPB) is an idiopathic chronic inflammatory pulmonary disease clinically characterized by cough, sputum, and chronic sinusitis. Although the average age of onset is 40 years, DPB occasionally occurs in children and is often misdiagnosed as asthma. Long-term therapy with macrolide antibiotics significantly improves survival in DPB. Herein, we report the case of a 16-year-old man who had been treated for asthma and was referred to our department as transition from the Department of Pediatrics. Adequate auscultation to detect squawks and history taking of purulent sputum led to the correct diagnosis and appropriate treatment, which improved his quality of life.

Short-term Clinical Outcome of Previously Untreated and Treated Schizophrenia and Impact of Duration of Untreated Psychosis

Background

Duration of untreated psychosis (DUP) is an important modifiable factor affecting schizophrenia outcomes. A dearth of research in India on untreated versus treated schizophrenia warrants further research.

Methods

This was a longitudinal study in a tertiary hospital over 2 years. Inpatients diagnosed with schizophrenia (N = 116), aged 18-45, were divided into untreated and treated groups. Diagnostic confirmation, severity assessment, and clinical outcome were done using ICD-10 criteria, Positive and Negative Syndrome Scale (PANSS), and Clinical Global Impression (CGI) scale. Follow-up was done at 12 and 24 weeks. DUP was measured, and its association with the outcome was assessed.

Results

Final analysis included 100 patients, 50 each of previously untreated and treated. Untreated patients had lower age and duration of illness (DOI), but higher DUP (p < .001). Treated patients showed much improvement on CGI-I at 12 weeks (p = .029), with no difference at 24 weeks. PANSS severity comparison showed no difference, and both groups followed a declining trend. In untreated patients, age of onset (AoO) was negatively correlated with severity (except general symptoms at baseline) at all follow-ups ('r' range = -0.32 to -0.49, p < .05), while DOI showed a positive correlation with negative and general symptoms at 12 weeks (r ~ 0.3, p < .05). Treated patients showed inconsistent and lower negative correlation between AoO and PANSS, with no correlation between severity and DOI. The mean sample DUP was 17.9 ± 31.6 weeks; it negatively correlated with education (r = -0.25, p = .01) and positively with PANSS severity ('r' range = 0.22 to 0.30, p < .05) at all follow-ups, especially negative symptoms. Patients with no or minimal improvement on CGI at 24 weeks had higher DUP (Quade's ANOVA F[1,98] = 6.24, p = .014).

Conclusion

Illness variables in untreated schizophrenia affect severity, which has delayed improvement than treated schizophrenia. Higher DUP is associated with negative symptoms of schizophrenia.

Erratum to: Rheological, Physicochemical, Microbiological, and Aroma Characteristics of Sour Creams Supplemented with Milk Protein Concentrate

[This corrects the article DOI: 10.5851/kosfa.2023.e16.].

Primary lung adenocarcinoma in transplanted lung in post bilateral lung transplantation

Key Clinical Message

Primary lung cancer was reported by a bilateral lung transplant patient without any risk factors. Single lung transplantation should be contemplated instead of double lung transplantation as it has been shown to increase the risk of lung cancers.

Abstract

This is a case report of a 37-year-old woman, with no history of smoking, who developed adenocarcinoma in her transplanted lung 17 years post transplantation. The development of lung cancer 17 years after transplantation is considered as a rare finding in this case report. According to the Annual Report on Cardiothoracic Organ Transplantation 2019-2020, the NHS Blood and Transplant Data, approximately 156 lung transplants were performed in the UK during 2019-2020. The third most common primary disease group recipient was cystic fibrosis and bronchiectasis. There are several medical complications described in the recipients' post-lung transplantation, and the increased risk of lung malignancy due to immunosuppression is well-established in comparison to the general population. Most cancers, however, develop in the native lung following a single lung transplant. Several cases of lymphoproliferative malignancies in the transplanted lung have been reported following bilateral lung transplantation. This is a case report of a 37-year-old woman with no history of smoking who developed adenocarcinoma in her transplanted lung 17 years later. This patient underwent lobectomy via thoracotomy and was discharged home in good condition. Only a few cases of patients developing primary lung cancer in the transplanted lung with no recipient risk factor have been reported in the literature to date. The development of lung cancer 17 years after transplantation was a rare finding in this case report.

[99m Tc] Tc-MDP bone SPECT/CT diagnosing unstable slipped capital femoral epiphysis with secondary AVN in a patient with misleading knee pain

Bone scan is highly sensitive whole-body imaging with relative low radiation in patients with non-localized skeletal symptoms. Patient is 12-year-old boy with Down syndrome, suffering recent claudication and exacerbated left knee pain unable to walk even with crutches. Three-dimensional Single photon emission computed tomography/Computed tomography (SPECT/CT) detected left slipped capital femoral epiphysis (SCFE) and secondary Avascular necrosis (AVN).

Port-site hernia: A potentially severe complication of minimally invasive surgery

Key Clinical Message

Recently, the number of minimally invasive surgeries (MIS) is increasing; however, a specific postoperative complication of MIS such as port-site hernia needs to be recognized. A persistent postoperative ileus after MIS is rare and such symptoms need to be recognized as a probable sign of a port-site hernia.

Abstract

Recently, minimally invasive surgery (MIS) approaches for early endometrial cancer have shown non-inferior oncologic outcomes with better perioperative morbidity than open approaches. Nevertheless, port-site hernias are a rare but specific surgical complication of MIS. Knowing the clinical presentation, surgery for port-site hernias could help clinicians manage this condition.

Imatinib associated temporal bone osteonecrosis

Tyrosine kinase inhibitors have substantially improved survival in patients with gastrointestinal stromal tumors (GIST) and chronic myeloid leukemia (CML). We report the first association between long-term imatinib use and temporal bone osteonecrosis, highlighting the importance of prompt ENT evaluation of such patients with new otological symptoms.

Point-of-care ultrasound aided diagnosis and management of peritoneal parenteral nutrition extravasation in a preterm baby: A case report

POCUS could identify some of UVC complications at the bedside. It complements the clinical picture and helps narrowing the deferential diagnosis when there is a clinical deterioration.

Safety evaluation of the food enzyme triacylglycerol lipase from the genetically modified Saccharomyces cerevisiae strain LALL-LI

The food enzyme triacylglycerol lipase (triacylglycerol acylhydrolase, EC 3.1.1.3) is produced with the genetically modified Saccharomyces cerevisiae strain LALL-LI by Lallemand Inc. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism, but not from recombinant DNA. It is intended to be used in baking processes. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.42 mg TOS/kg body weight per day in European populations. The production strain of the food enzyme fulfils the requirements for the qualified presumption of safety (QPS) approach to safety assessment. Therefore, the Panel considered that toxicological tests are not needed for the assessment of this food enzyme. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Stemmed hemiarthroplasty with a suture collar and a common platform system for acute proximal humeral fractures

Background

Hemiarthroplasty for acute proximal humeral fractures gives disappointing results, often due to rotator cuff insufficiency. Better tuberosity fixation might improve results. Therefore, the aim of this study was to: 1) report the outcome of a stemmed hemiarthroplasty with a common platform system and a modular suture collar; 2) compare the outcome with that of a standard stemmed hemiarthroplasty; 3) report the feasibility of revision arthroplasty with retention of the stem; and 4) to evaluate the association between tuberosity healing and functional outcome.

Methods

Forty-four fractures that were deemed not suitable for nonsurgical treatment or open reduction and internal fixation were treated with the Global Unite fracture system between January 2017 and July 2019. The functional and radiographic results at 2 years were compared with the results of 44 Global Fx arthroplasties. The results of patients who had adequate healing of the greater tuberosity were compared with the results of patients who had severe malunion or nonunion (resorption).

Results

Mean Oxford Shoulder Score, Constant-Murley Score, and Western Ontario Osteoarthritis of the Shoulder index was 33 (range: 10 to 48), 40 (range: 10 to 98), and 68 (range: 18 to 98) at 2 years. There were no differences in functional outcome scores or in the risk of inadequate healing of the greater tuberosity between the Global Unite and the Global Fx systems. Five (11%) patients underwent revision surgery with retention of the stem. Inadequate tuberosity healing was associated with an inferior Constant-Murley Score (mean difference: 6; 95% confidence interval: 1 to 10, P = .01) and an inferior Oxford Shoulder Score (mean difference: 9; 95% confidence interval: 1 to 16, P = .03).

Conclusion

The use of stemmed hemiarthroplasty with a suture collar did not improve the healing of the greater tuberosity or the functional outcome. Five arthroplasties were revised with retention of the stem. This possibility could be arguments for using the Global Unite system when a stemmed hemiarthroplasty is used for acute proximal humeral fractures.

Esophageal cancer operation in the COVID-19 era: are the outcomes different from its past in an observational cohort study?

COVID-19 spread rapidly and potentially affected every medical profession, including surgery. This study aims to compare the postoperative outcomes of oesophageal cancer surgeries in COVID-19 age and a year before.

Methods

This retrospective cohort study was performed as a single-centred study from March 2019 to March 2022 at Cancer institute, Tehran, Iran. Demographic data, cancer type, surgical procedures, and postoperative outcomes and complications were compared between the two groups pre-COVID-19 and during the COVID-19 pandemic.

Results

Totally, 120 patients enroled in the study, of which 57 underwent surgery before the COVID-19 pandemic, and 63 during the COVID-19 pandemic. The mean age in these groups was 56.9 (±12.49) and 58.11 (±11.43), respectively. Females included 50.9% and 43.5% of individuals who underwent surgery before and during the COVID-19 pandemic. The interval between admission and surgery was significantly shorter in patients underwent surgery during the COVID-19 pandemic (5.17 vs. 7.05; P=0.013). However, there was no significant difference between time interval between surgery and discharge [11.68 (7.81) vs. 12 (6.92); P=0.689]. Aspiration pneumonia was the most common complication in both groups. There was no significant difference between postoperative complications in both groups.

Conclusion

Outcomes of oesophageal cancer surgeries in COVID-19 age in our institution were comparable with the year before the pandemic. The decrease in the time interval between surgery and discharge did not lead to an increase in postoperative complications and could be noted for post-COVID-19 era policymaking, too. This study suggests not postponing any of the surgical treatments for oesophageal cancer in the COVID-19 era.

Metagenomic next-generation sequencing for the diagnosis of oral and maxillofacial space infections

Background/purpose

Metagenomic next-generation sequencing (mNGS) has been widely used for the detection of pathogens causing infectious diseases. This study aimed to evaluate the potential ability of mNGS to detect pathogens causing oral and maxillofacial space infection (OMSI) and compare the results with those of the traditional diagnostic microbial culture method.

Materials and methods

We retrospectively reviewed the data of 218 patients diagnosed with OMSI who underwent microbial culture and mNGS at the Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, from July 2020 to January 2022.

Results

The positivity rate of mNGS (216 cases) was significantly higher than that of microbial culture (123 cases). The most frequently detected bacteria were different between these two detection methods. Streptococcus constellatus (16.05%, 35), Streptococcus anginosus (15.69%, 34) and Klebsiella pneumoniae (6.88%, 15) were the most commonly isolated bacteria by culture. However, Peptostreptococcus stomatis (61.47%, 134), Parvimonas micra (68.35%, 149) and Streptococcus constellatus (57.34%, 125) were the most commonly detected bacteria by mNGS. mNGS also has advantages in diagnosing viral infections. The optimal numbers of diagnostic reads were 1162 and 588 for the diagnosis of Streptococcus anginosus and Streptococcus constellatus infections, respectively. Read numbers were significantly correlated with C-reactive protein (CRP), procalcitonin (PCT), and blood glucose levels and neutrophil percentage (NEUT%).

Conclusion

For pathogens causing OMSI, mNGS had a higher rate of microbial pathogen detection and remarkable advantages in identifying coinfections involving viruses and fungi. The read numbers for mNGS are important for diagnostic accuracy and disease severity evaluation.

A case of mucosal-associated lymphoid tissue lymphoma of the urachus

Introduction

Urachus carcinoma is a rare malignancy with an aggressive potential and a poor prognosis, and evidence is limited for its diagnosis and treatment.

Case presentation

A 75-year-old man underwent fluorodeoxyglucose positron emission tomography/computed tomography for staging prostate cancer, and a mass (standardized uptake value max 9.5) was observed on the outside of the urinary bladder dome. T2-weighted magnetic resonance imaging showed the urachus and a low-intensity tumor, which suggested a malignant tumor. We suspected urachal carcinoma and performed total resection of the urachus and partial cystectomy. Pathological examination revealed mucosa-associated lymphoid tissue lymphoma with cells positive for CD20 and negative for CD3, CD5, and cyclin D1. After the surgery, no recurrence has been observed for more than 2 years.

Conclusion

We encountered an extremely rare case of mucosa-associated lymphoid tissue lymphoma of the urachus. Surgical resection of the tumor provided an accurate diagnosis and good disease control.

Examination of hip function and muscle activity during clam exercise

[Purpose] Clam exercise is commonly used to strengthen hip abductor muscles. This study aimed to classify the directions of greater trochanter movement during clam exercise and examine whether this classification reveals any differences in the characteristics of muscle activities. [Participants and Methods] Twenty healthy male participants were included and were divided into three groups according to the direction of greater trochanter movements during clam exercise: diagonally upward, backward, and upward. Muscle activity of the gluteus medius, gluteus maximus, tensor fascia lata, and external oblique was measured during clam exercise, along with the direction of greater trochanter movement and maximum muscle strength in the clam exercise limb position. [Results] In the diagonally upward group, the gluteus medius muscles showed higher activity than the other three muscles, and their activity was higher in the diagonally upward and backward groups than in the upward group. [Conclusion] The tension and action vector of the muscles changed due to differences in the direction of the greater trochanter movement caused by the movement pattern of each participant. The muscle activity around the hip joint changes with the direction of greater trochanter movement during clam exercise.

Frosted branched angiitis due to viral meningo-encephalitis and ocular toxoplasmosis; a rare case report from Nepal

Frosted branched angiitis (FBA) is characteristic florid translucent retinal perivascular sheathing of both arterioles and venules in association with variable uveitis and vasculitis affecting the entire retina. The vascular sheathing is supposed to be an immune-mediated reaction, possibly due to immune complex deposition in vessel walls secondary to various underlying etiologies. The authors aim to report a case of FBA secondary to herpes simplex virus and Toxoplasma gondii infection causing the diagnostic dilemma. This is the first case report on FBA from Nepal.

Case report

An 18-year-old young boy hospitalized with the diagnosis of acute viral meningo-encephalitis presented with the complaint of diminution of vision and floaters in both eyes for a week. Herpetic infection was confirmed with the cerebro-spinal fluid analysis and was under antiviral drugs. His presenting visual acuity was 20/80 in both eyes and ocular features were suggestive of FBA. The vitreous sample analysis revealed raised toxoplasma titre so intravitreal clindamycin was administered twice. The ocular features resolved in the subsequent follow ups with intravenous antiviral treatment and intravitreal antitoxoplasma treatment.

Conclusions

FBA is a very rare clinical syndrome secondary to many immunological or pathological causes. So, possible etiologies must be ruled out for timely management and good visual prognosis.

Autoimmune hemolytic anemia associated with COVID-19 infection: a rare case report

Coronavirus disease 2019 (COVID-19) is an illness due to severe acute respiratory syndrome, symptoms and severity of disease varies from patient to patient, autoimmune hemolytic anemia (AIHA) in children with COVID-19 is rare.

Case presentation

A 12-year-old female presented with fever, headache, myalgia, and hematuria. At admission, she was hemodynamically stable, severe anemia was present, and severe acute respiratory syndrome coronavirus 2 infection was confirmed by RT-PCR. The diagnosis of AIHA was confirmed and treated.

Discussion

There are few reports of patients with AIHA and COVID-19. However, the majority of patients in these reports also have autoantibodies and other underlying conditions known to be associated with the development of AIHA.

Conclusion

In this current pandemic, it should be taken into account that previously healthy children with severe acute respiratory syndrome coronavirus 2 infection have been found to have severe hemolytic anemia in the absence of COVID-19.

Evaluation of physicochemical characteristics and centerline temperatures of Sr ceramic waste form

When disposing of spent fuel, nuclides such as Cs-137 and Sr-90, which generate short-term decay heat, must be removed from the spent nuclear fuel for efficient storage facility utilization. The Korea Atomic Energy Research Institute (KAERI) has been developing a nuclide management process that can enhance disposal efficiency by sorting and collecting primary nuclides and a technology for separating Sr nuclides from the spent nuclear fuels using precipitation and distillation. In this study, we prepared Sr ceramic waste form, SrTiO₃, using the solid-state reaction method to immobilize the Sr nuclides, and its physicochemical properties were evaluated. Moreover, the radiological and thermal characteristics of the Sr waste form were evaluated by estimating the composition of Sr nuclides considering the spent nuclear fuel history such as burn-up and cooling period. The waste form was found to be stable with good mechanical strength and leaching properties in addition to a low coefficient of thermal expansion, which would be advantageous for intermediate storage. Based on the experimental and radiological results, the centerline temperature of the waste form caused by Sr-90 nuclide was estimated using the steady-state conduction equation. The centerline temperature increased with increasing diameter of the waste form. When generating the SrTiO₃ waste form using the Sr nuclide recovered after a cooling period of 10 years, the centerline temperature was estimated to exceed the melting point of SrTiO₃ at a diameter of 0.275 m, under all burn-up conditions. These results provide fundamental data for the management and intermediate storage of Sr waste.

Multiple origins define the genetic structure of tiger shrimp Penaeus monodon in the colombian Caribbean Sea

The tiger shrimp Penaeus monodon is a native species of the Indo-Pacific Ocean that was introduced to promote its cultivation in several American countries, including Colombia. As a result of inappropriate aquaculture practices, it has established itself in the wild in almost all the Colombian Caribbean Sea. To evaluate the genetic diversity, population structure, and origin of the founder populations, samples from three sites in the Colombian Caribbean were analyzed from 10 microsatellite loci and the mitochondrial DNA Control Region. Genetic diversity similar to native populations was found to be present in three relatively discrete populations and their origin is related to natural populations from Thailand, the Philippines, Taiwan and China. We discuss how oceanographic conditions and culture systems of tiger shrimp facilitated the success of biological invasion processes in marine ecosystems of the Colombian Caribbean.

Palladium complexes containing NNN pincer type ligands and their activities in Suzuki-Miyaura cross coupling reaction

Five new NNN pincer-type ligands and their palladium complexes were successfully synthesised and characterised by FT-IR, ¹H NMR, ¹³C NMR, and UV-vis analyses. TEM analysis was used to observe the morphological character of the black residues obtained from the fourth cycle of the reusability test. Furthermore, suitable crystals of the N²,N⁶-bis(2-tert-butylphenyl)pyridine-2,6-dicarboxamide and its palladium complex were elucidated with the X-ray single crystal diffraction method. Both the ligand and its palladium complex crystallise in a monoclinic system with space group P2₁/c for the H₂L⁴ and C2/c for the palladium complex. The structure of the pincer ligand and its palladium complex were stabilised by intramolecular and intermolecular C-H⋅⋅⋅O, C-H⋅⋅⋅N, and N-H⋅⋅⋅N contacts. A Suzuki-Miyaura cross-coupling reaction between aryl halides and phenylboronic acid was used to assess the catalytic abilities of the palladium pincer complexes. All of the prepared complexes exhibited considerable catalytic activity. However, complexes 4 (Acetonitrile-N²,N⁶-bis(2-tert-butylphenyl)pyridine-2,6-dicarboxamidopalladium(II)) and 5 (Acetonitrile-N²,N⁶-bis(2-nitrophenyl)pyridine-2,6-dicarboxamidopalladium(II)) provided almost 100% conversion with nearly 100% yield in the reaction between 4-bromotoluene and phenylboronic acid. Furthermore, these active complexes catalysed the reaction of the sterically hindered and deactivated substrates (1-Bromo-4-izobutylbenzene and 2-bromo-6-methoxynaphthalene) with phenylboronic acid, and complete conversion and yields up to 100% were achieved in a short time with the 2-bromo-6-methoxynaphthalene.

A hybrid DEMATEL and social network analysis model to identify factors affecting learners' satisfaction with MOOCs

Massive Online Open Courses (MOOCs) offer free access to training in various topics in all fields. However, the low percentage of course completion by learners is a significant challenge for these platforms. Previous studies on this challenge have investigated user behavior and concerned topics in discussion forums, but these data are mostly momentary and cannot be used for long-term improvement. Thus, this study aimed to address this gap by analyzing learners' comments to identify the factors affecting user satisfaction and prioritize them to improve MOOC platforms. The purpose was to analyze the feedback and actual experiences of users shared through their comments on MOOC online platforms to explore factors affecting user satisfaction to optimize MOOC platforms. To achieve this, sentiment analysis and topic modeling techniques were applied to the user feedback on courses with popular topics, such as Skills for Data Science Teams and Data-Driven Decision Making, available on Coursera.com. The study used DEMATEL analysis, which uses a relation matrix of factors to rank them based on their interrelationships, and network analysis to prioritize the factors that should be improved to achieve the highest user satisfaction. The effect of the proposed approach was investigated through a case study on a course from Coursera. The findings demonstrate that the suggested method has the potential to assist MOOC platforms in several ways. Firstly, it enables the identification of course strengths and weaknesses. Secondly, it allows for the identification of factors that influence learner satisfaction by analyzing user feedback. Lastly, it aids in prioritizing the factors that should be enhanced to attain optimal user satisfaction, thus leading to overall improvement in the status of the MOOC platform.