Polystyrene bis[N-(2-pyridyl) sulfonamide] palladium(II): Synthesis, characterization as a catalyst for coupling reactions

<p>The [N-(2-pyridyl)] para-styrene sulfonamide (PSS) was prepared as a monomer, from the reaction of para-styrene sulfonyl chloride and 2-amino pyridine in the presence of potassium hydroxide solution 0.5 M as a base, and CH₃Cl. Polystyrene [N-(2-pyridyl) sulfonamide] (PPSS) was synthesized from the polymerization of [N-(2-pyridyl)] para-styrene sulfonamide (PSS). The Polystyrene bis [N-(2-pyridyl) sulfonamide] palladium (II) as a polymer- supporting palladium complex was also prepared from the reaction of PdCl₂ (CH₃CN)₂ with PPSS in the presence of KOH 0.5 M. Polystyrene bis [N-(2-pyridyl) sulfonamide] palladium (II) is produced as a novel heterogeneous catalyst for coupling reactions for C-C bond formation. This method includes higher yield and has an easier work-up procedure. The structures of the monomer, polymer and its Pd complex were confirmed by using FT-IR and ¹H-NMR spectroscopy. Elemental analysis of Pd by inductively coupled plasma (ICP) technique and hot filtration test showed loading of the metal into solution from the catalyst The heterogeneous catalyst was recycled without any loss in its properties.</p> <p></p

Finite element analysis of miniscrew placement in mandibular alveolar bone with varied angulations

Summary Background: Titanium miniscrews are increasingly used as orthodontic anchorage. Various factors are known to affect the stability of miniscrew. Placement angle is one of the most controversial issues in this area. Thus, the aim of this finite element study was to evaluate the influence of placement angle and direction of force on the stability of miniscrews. Materials and methods: Finite element analysis was performed using miniscrews inserted into 1mm of cortical bone and 10mm of trabecular bone at angles of 30, 60, 90, 120, and 150 degrees to the alveolar bone. Force of 2 Newton (N) was applied to the heads of the miniscrews in two directions of 0 and 30 degrees. Results: The finite element analysis showed that inserting miniscrews at 90 degree angle would provide better anchorage than 30, 60, 120, and 150 degree angles at either direction of force. The least trabecular bone von Mises stress was 5.6MPa at 90 degrees at both directions of force and the least cortical bone stress was 31.2MPa at 90 degrees at both directions of force. Conclusions: Insertion of miniscrews at angles less than or greater than 90 degrees to the alveolar process bone might decrease the anchorage stability of the miniscrew. © The Author 2014. Published by Oxford University Press on behalf of the European Orthodontic Society

GBS as unusual presentation of neurobrucellosis: A rare case report

Brucellosis is a zoonotic disease caused by small intracellular aerobic Gram-negative bacilli. The literature has frequently documented instances of the gastrointestinal, hepatobiliary, and skeletal systems being involved. In 3%-5% of brucellosis patients, neurobrucellosis has been identified. Guillain-Barré syndrome (GBS) is a disorder of the peripheral nervous system. Acute peripheral neuropathy mimicking GBS caused by brucellosis is rarely reported. Our case is of a 34-year-old male presenting with a 3-week history of weakness in the upper limbs. There was a clear history of milk product consumption preceding the onset of symptoms. Examination showed paraesthesia and muscles paralysis. Brucellosis was confirmed via blood test, and GBS was confirmed via imaging and neuroelectrophysiological assessment. The patient was treated with plasma exchange (PLEX) and commenced on rifampicin, doxycycline and gentamicin during their hospitalization. The patient was discharged with a course of rifampicin and doxycycline to complete. In patients with acute paralysis and GBS-like symptoms, Imaging should be done in addition to serological tests for brucellosis

Biased Deep Learning Methods in Detection of COVID-19 Using CT Images: A Challenge Mounted by Subject-Wise-Split ISFCT Dataset

Accurate detection of respiratory system damage including COVID-19 is considered one of the crucial applications of deep learning (DL) models using CT images. However, the main shortcoming of the published works has been unreliable reported accuracy and the lack of repeatability with new datasets, mainly due to slice-wise splits of the data, creating dependency between training and test sets due to shared data across the sets. We introduce a new dataset of CT images (ISFCT Dataset) with labels indicating the subject-wise split to train and test our DL algorithms in an unbiased manner. We also use this dataset to validate the real performance of the published works in a subject-wise data split. Another key feature provides more specific labels (eight characteristic lung features) rather than being limited to COVID-19 and healthy labels. We show that the reported high accuracy of the existing models on current slice-wise splits is not repeatable for subject-wise splits, and distribution differences between data splits are demonstrated using t-distribution stochastic neighbor embedding. We indicate that, by examining subject-wise data splitting, less complicated models show competitive results compared to the exiting complicated models, demonstrating that complex models do not necessarily generate accurate and repeatable results.Applied Science, Faculty ofNon UBCEngineering, School of (Okanagan)ReviewedFacultyResearche