Aberrant right coronary artery in an elderly Nigerian with recent dyspnoea detected on coronary CT angiogram

An anomalous origin of the right coronary artery has been documented in up to 0.92% of the general population, which is more common than an anomalous origin of the left coronary artery. We present a case of an elderly hypertensive man who developed mild dyspnoea on exertion for 3 months with associated retro-sternal pain as well as occasional palpitation which all tend to subside at rest. An electrocardiogram showed evidence of left atrial enlargement. A coronary computed tomographic angiogram was acquired with a 160-slice scanner which revealed the right coronary artery to originate from the left aortic sinus with a retro-aortic pattern of anatomical course. Vascular wall calcifications were noted with multilevel luminal narrowing on the left anterior descending however distal opacification was adequate. Our case further depicts the reason for keeping in mind anatomical variations while evaluating cardiac pathologies even among Black Africans.

Perindopril and losartan attenuate pro-coagulation factors in human adipocytes exposed to SARS-CoV-2 spike protein

Thrombotic events are highly prevalent in coronavirus disease 2019 (COVID-19), especially in patients presenting with risk factors of adverse outcomes such as obesity. Recently, the associations between the angiotensin converting enzyme 2 (ACE2) pathway and thrombosis have been reported. Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARBs) are widely used cardiovascular pharmacologic agents that upregulate ACE2 levels. An observation of the alterations in pro-coagulation factors after exposure to ACEIs and ARBs may provide valuable insight into the thrombosis mechanism and how it may relate to ACE2. This study use adipose tissue harvested from an obese male donor was isolated and exposed to perindopril, losartan, and ACE2 recombinant as binding assay, following exposure with 10 nm of SARS-CoV-2 S1 spike protein. After 48 hours, tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) as pro-coagulation factors as well as ACE2 levels and binding evaluated. The results shows TF level was significantly reduced in Perindopril group compared to control (4.834; p=0.005), while a non-significant reduction was observed in Losartan group (5.624; p=0.111). However, Losartan group showed a better reduction of PAI-1 levels (2.633; p≤0.001) than Perindopril group (3.484; p=0.001). These findings were consistent with the observations in ACE2 recombinant group, suggesting that both drugs lowered the bindings of ACE2 and SARS-CoV-2 spike proteins. This study indicated that both perindopril and losartan may attenuate pro-coagulation factors in human adipocytes exposed to SARS-CoV-2 spike proteins, and therefore showcased a potential role of ACE2 in the mechanism of COVID-19-related thrombosis. Further investigation in non-COVID-19 populations should commence and may be of value to expanding this potential in general cardiovascular diseases.

Soliton mode-locked pulse generation with a bulk structured MXene Ti3AlC2 deposited onto a D-shaped fiber

We propose a bulk structured MXene, Ti₃AlC₂ deposited onto D-shaped fiber for soliton generation in an erbium-doped fiber laser (EDFL) cavity. Our saturable absorber (SA) device, based on MAX phase, was prepared by using stirring and ultrasonic vibration, which offer easier sample preparation compared with its 2D counterparts. By means of the polishing wheel technique, we fabricated a D-shaped fiber with a controlled polishing depth and incorporated the MAX phase Ti₃AlC₂ solution onto its polishing region. We obtained a mode-locked soliton pulse with the proposed MAX phase D-shaped (MAX-DS) SA in EDFL cavity. The pulse width, repetition rate, and central wavelength of the pulse train are 2.21 ps, 1.89 MHz, and 1557.63 nm, respectively. The polarization-insensitive EDFL cavity initiated a soliton operation with superior stability as the pump power tuned from 21 to 131 mW; further, the ML laser exhibits an average power of 15.3 mW, peak power of 3.8 kW, and pump efficiency of 12.5%. The MAX-DS SA incorporated inside the EDFL reveals efficient output performance, with a pulse energy of 8.14 nJ, the highest ever reported, to our best knowledge, among D-shaped fiber-based SA.

Q-switched ytterbium-doped fiber laser based on evanescent field interaction with lutetium oxide

We demonstrated lutetium oxide (${\textrm{Lu}_2}{\textrm{O}_3}$Lu₂O₃) deposited onto D-shaped fiber producing Q-switched ytterbium-doped fiber laser (YDFL) with an operating wavelength of 1037 nm. D-shaped fiber ${\textrm{Lu}_2}{\textrm{O}_3}$Lu₂O₃ as a saturable absorber (SA) was prepared using a polishing-wheel technique by polishing 2 times to establish an excellent evanescent field interaction between material and light on the surface of the polished region. The SA was deployed into a YDFL to generate Q-switching. The proposed D-shaped fiber ${\textrm{Lu}_2}{\textrm{O}_3}$Lu₂O₃ initiated pulses as short as 3.6 µs, with the highest repetition rate of 65.8 kHz. Stability of the SA is proven, as it produced stable pulses within the pump power of 99 to 133 mW with an SNR of 62.13 dB. Q-switched YDFL generates pulses with an output power of 0.93 to 1.99 mW and pulse energy of 17 to 30 nJ. We obtained a laser cavity with the optical-to-optical efficiency of 3.33%, which was the highest among D-shaped fiber-deposited SA materials in YDFL. Therefore, ${\textrm{Lu}_2}{\textrm{O}_3}$Lu₂O₃ deposited onto D-shaped fiber can be deployed as an SA in YDFL for a portable Q-switched laser source.