Efficient power-electronic converters for electric vehicle applications

This paper introduces advanced power-electronic converter topologies for Electric Vehicles (EVs) using a four-phase DC/DC interleaved boost converter (FP-IBC) and a five-level T-type DC/AC multilevel converter. A comparison between the proposed topologies and other converter topologies is performed and discussed. The simulation results are analysed to evaluate the converters based on power loss calculations and harmonic analysis. The converters are studied at different switching frequencies and various loading conditions to reflect their effects on the converter losses. The results highlight the proposed converters' higher efficiency compared to other studied converter topologies in electric vehicle applications

Highly Specific and Reversible Fluoride Sensor Based on an Organic Semiconductor

International audienc

Appendiceal Diverticulitis in a Young Female Diagnosed on Pathology after Laparoscopic Appendectomy for Acute Appendicitis

Background. Appendiceal diverticulitis is a rare cause of inflammation of the appendix, which may mimic acute appendicitis. Its diagnosis is often delayed, and its occurrence carries an increased risk of significant complications, such as perforation. Case Presentation. A 23-year-old woman presented with sudden onset, severe, right lower quadrant abdominal pain and nausea. Her WBC was elevated, and abdominal CT showed findings indicative of acute appendicitis with a 13 mm fluid-filled appendix and local stranding. During laparoscopic appendectomy, significant inflammation was found around the appendix with some mucous material around the tip. The appendix base was not involved, and an endoloop was used to secure the stump. No other intra-abdominal abnormalities were observed. The patient recovered uneventfully. Pathology showed no classic appendicitis but appendiceal diverticulitis with signs of perforation. Discussion. Appendiceal diverticulitis is a rare condition which cannot be distinguished from acute appendicits clinically and on imaging. Diagnosis may be established based on pathology such as in our case. Appendectomy is indicated in appendiceal diverticulitis, and an appendix diverticulum is incidentally found during surgery or other investigations. This is due to the increased risk of perforation and the reported development of malignant tumors, including the appendix carcinoid

Longitudinal Gastrectomy for Nonbariatric Indications

Background. Sleeve gastrectomy is the most commonly performed bariatric procedure. Laparoscopic longitudinal gastrectomy (LLG) may be indicated for other indications. Patients and Methods. Two men and two women aged 67, 72, 77, and 80 years underwent LLG for nonbariatric indications with two having normal weight, one being cachectic, and one severely obese. Results. LLG was discussed with patients prior to surgery, but decision for LLG was made during surgery after contemplating other surgical options. A wide sleeve over a 42 French bougie was created with the staple line being oversewn with running 3–0 silk. Indications included a bleeding Dieulafoy lesion that failed endoscopic clipping, fundus gland polyposis found during paraesophageal hernia repair, fundus nodules suspected to be leiomyosarcoma metastases revealing splenosis on final pathology, and significant gastric dilatation associated with organoaxial gastric volvulus. Three patients had an uneventful recovery; the severely obese patient temporarily lost weight but died after two years from a stroke. The last patient developed dysphagia due to an alpha-loop in the sleeve, which was managed by endoscopic stenting. The device subsequently migrated and was laparoscopically removed, with a side-side gastrogastrostomy performed to straighten the alpha-loop. The patient tolerated food better and with overnight PEG tube feeds gained weight but continued heavy smoking. He died after one year from COPD exacerbation. Conclusion. LLG seems to be an appropriate intervention for various gastric pathologies. Training of residents and fellows in the minimally invasive surgical steps of LLG is encouraged

Design of hybrid clay/ polypyrrole decorated with silver and zinc oxide nanoparticles for anticorrosive and antibacterial applications

In this work, a novel and cost-effective bentonite intercalated with polypyrrole Zinc oxide-silver nanocomposite (B-PPy/ZnO) hybrid material was prepared via in situ photopolymerization of pyrrole in the presence of silanized bentonite and zinc oxide nanoparticles and using silver nitrate as an initiator. The as-prepared Bentonite-polypyrrole/ZnO hybrid material was found to be black, exfoliated with a polypyrrole-rich surface decorated with ZnO and silver nanoparticles in a metallic state. We evaluated the propensity of the prepared hybrid material as an eco-friendly, anticorrosive, and antibacterial coating for carbon steel. The corrosion resistance efficiency study of B-PPy/ZnO composite incorporated with the epoxy matrix was carried out in a 3.5 % NaCl solution. B-PPy/ZnO 4 wt% composite coating on carbon steel was observed to exhibit best corrosion protection property, with High charge transfer resistance were value (9.85 MΩ cm−2) compared to 0.213 MΩ cm-2 in the presence of pure epoxy. Cytotoxicity assay was carried out on an A549 epithelial cell line. Moreover, B-PPy/ZnO showed a reduction in Escherichia coli bacterial growth by ∼86 % with a minimum inhibitory concentration of 0.03 mg ml-1. The results obtained herein will open new routes to the preparation of efficient ecofriendly anticorrosion and antibacterial coatings.This study was made possible by student grant QUST-1-CAM-2019-9 awards, from Qatar University. The findings made herein are solely the responsibility of the authors

Novel 3-phenylquinazolin-2,4(1H,3H)-diones as dual VEGFR-2/c-Met-TK inhibitors: design, synthesis, and biological evaluation

Abstract Multitarget anticancer drugs are more superior than single target drugs regarding patient compliance, drug adverse effects, drug-drug interactions, drug resistance as well as pharmaceutical industry economics. Dysregulation of both VEGFR-2 and c-Met tyrosine kinases (TKs) could result in development and progression of different human cancers. Herein, we reported a novel series of 3-phenylquinazolin-2,4(1H,3H)-diones with thiourea moiety as dual VEGFR-2/c-Met TKs. Compared to sorafenib, cabozantinib went behind VEGFR-2 inhibition to target c-Met TK. The dual VEGFR-2/c-Met inhibitory activity of cabozantinib is due to a longer HB domain than that of sorafenib. Based on pharmacophore of cabozantinib analogues, we designed new dual VEGFR-2/c-Met TKs. We synthesized the target compounds via a new single pot three-component reaction. The cytotoxic activity of synthesized compounds was conducted against HCT-116 colorectal cancer cell line. Compounds 3c and 3e exhibited the highest cytotoxic activity against HCT-116 cell line (IC50 1.184 and 3.403 µM, respectively). The in vitro enzyme inhibitory activity was carried out against both VEGFR-2 and c-Met TKs. Compound 3e has the highest inhibitory activity against both VEGFR-2/c-Met (IC50 = 83 and 48 nM, respectively). Docking studies showed that α-oxo moiety in quinazoline ring formed hydrogen bond HB with Met1160 residue in the adenine region of c-Met TK

Platinum degradation mechanisms in proton exchange membrane fuel cell (PEMFC) system: A review

Proton Exchange Membrane Fuel Cells (PEMFCs) have the perspective to intensely decrease global emission through environmentally-friendly potential. This review paper summarizes the degradation of platinum catalyst layer that has become a significant issue in the improvement of PEMFCs. The review intends to categorise and provide a clear understanding between disintegration and agglomerate that occurs during platinum degradation. In each process, different degradation mechanisms and their migration processes are presented. The improvement in platinum degradation as a function of increasing the performance of PEMFC is established. Prospects for addressing platinum degradation through the exploration of further experimental and numerical research are recommended. Lastly, this paper through recommendation attempts to prevent platinum degradation and reduces high costs associated with the replacement of catalysts in the PEMFCs

Structure properties relationships of liquid crystal bent core organic semiconductors based on benzo[2,1-b:3,4-b ']dithiophene-4,5-dione

We report the synthesis of a new diketone bridged dithiophene end-capped with the mesogenic functionalities: 2,7′-bis(alkoxy-biphenyl) and 2,7′-bis(alkoxy-phenyl)-benzo[2,1-b:3,4-b′]dithiophene-4,5-dione. Optical and electrochemical properties in solution were investigated by UV-visible absorption and cyclic voltammetry. Liquid crystal properties of these new materials were investigated by differential scanning calorimetry, optical polarizing microscopy, and X-ray diffraction studies. Both compounds exhibit layered phases though there are differences in the organisation of the phase structures. Thin films were implemented as active layers into organic thin-film transistors to evaluate the charge transport properties

A review of bipolar plates materials and graphene coating degradation mechanism in proton exchange membrane fuel cell

Proton exchange membrane fuel cells (PEMFCs) have the perception to strongly reduce global emissions through an environmentally friendly perspective. Graphene has drawn global attention and has positioned itself as a potential material for bipolar plates application. This study reviews the application of graphene and summarizes the degradation of graphene coating that has become a significant issue in the improvement of PEMFC's performance. In the analysis, the degradation and its dissolution processes are presented. The need to improve the material selection focused mitigation on fabrication defects that act as initiation sites for graphene coating degradation is recommended. Finally, this review through recommendation endeavors to prevent graphene coating degradation and reduces high costs associated with the replacement of bipolar plates in the PEMFCs

Tailored fabrication of iridium nanoparticle-sensitized titanium oxynitride nanotubes for solar-driven water splitting: Experimental insights on the photocatalytic-activity-defects relationship

Understanding the photocatalytic-activity-defects relationship of titanium oxynitride nanotubes (TiON-NTs) is important for tailoring their photocatalytic performance. Herein, we fabricated highly ordered and vertically aligned nanotube arrays of TiON-NT-functionalized with iridium nanoparticles denoted as (Ir/TiON-NTs) for solar-driven water splitting. Positron annihilation lifetime spectroscopy (PALS) and variable-energy positron annihilation spectroscopy (VEPAS) were performed to quantify the vacancy-type defects of Ir/TiON-NTs relative to TiON-NTs and TiO2-NTs. The results display that the Ir/TiON-NTs exhibit abundant defects such as small nitrogen vacancies, larger size vacancy clusters, and small voids. The obtained photocurrent density of the Ir/TiON-NTs (11.3 mA cm-2) is about 3.97, 5, and 11.89 times higher than that of Ir/TiO2-NTs, TiON-NTs, and TiO2-NTs, respectively. The Mott-Schottky analysis revealed the highest significant negative shift in the band potential and the lowest donor density of Ir/TiON-NTs compared to its counterparts. This result is attributed to the unique structural and compositional merits of Ir/TiON-NTs despite the abundant defects, which delay the charge recombination and improve the photocatalytic activity. The presented study may open new frontiers on engineering the defects of metal oxynitrides with metal-based catalysts for photocatalytic applications.This work is made possible by NPRP Grant no. NPRP 7-485-1-091 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors