Electronic and optical properties of metal-doped TiO2_2 nanotubes: Spintronic and photocatalytic applications

Due to their characteristic geometry, TiO$_2$ nanotubes (TNTs), suitably doped by metal-substitution to enhance their photocatalytic properties, have a high potential for applications such as clean fuel production. In this context, we present a detailed investigation of the magnetic, electronic, and optical properties of transition-metal doped TNTs, based on hybrid density functional theory. In particular, we focus on the $3d$, the $4d$, as well as selected $5d$ transition-metal doped TNTs. Thereby, we are able to explain the enhanced optical activity and photocatalytic sensitivity observed in various experiments. We find, for example, that Cr- and W-doped TNTs can be employed for applications like water splitting and carbon dioxide reduction, and for spintronic devices. The best candidate for water splitting is Fe-doped TNT, in agreement with experimental observations. In addition, our findings provide valuable hints for future experimental studies of the ferromagnetic/spintronic behavior of metal-doped titania nanotubes.Comment: 25 pages (preprint style), 10 figure

Response to Comment on (Novel two-dimensional porous graphitic carbon nitride C6N7 monolayer: A First-principle calculations [Appl. Phys. Lett. 2021, 119, 142102])

Recently, reported a comments on the our paper [Appl. Phys. Lett. 119, 142102 (2021)]. With our response, the APL journal rejected their non scientific comments. There are some ambiguities about their claim: 1-They can check the phonon dispersion of their structure to see ZA out-of-plane mode. 2-They report the uniaxial stress-strain responses in Fig 2., which is unrelated to our paper. For a more helpful understanding of the mechanical properties of the novel C6N7 monolayer, they can publish a paper. 3-They mentioned: Using the DFT method and with assuming a thickness of 3.35 A for the C6N7 monolayer based on graphene thickness. Why did they choose this thickness while we know our C6N7 monolayer is at without buckling? The distance of ZA out-of-plane movement of ions in C6N7 is different from Graphene.Comment: 1 pag

Effects of alirocumab on types of myocardial infarction: insights from the ODYSSEY OUTCOMES trial

Aims  The third Universal Definition of Myocardial Infarction (MI) Task Force classified MIs into five types: Type 1, spontaneous; Type 2, related to oxygen supply/demand imbalance; Type 3, fatal without ascertainment of cardiac biomarkers; Type 4, related to percutaneous coronary intervention; and Type 5, related to coronary artery bypass surgery. Low-density lipoprotein cholesterol (LDL-C) reduction with statins and proprotein convertase subtilisin–kexin Type 9 (PCSK9) inhibitors reduces risk of MI, but less is known about effects on types of MI. ODYSSEY OUTCOMES compared the PCSK9 inhibitor alirocumab with placebo in 18 924 patients with recent acute coronary syndrome (ACS) and elevated LDL-C (≥1.8 mmol/L) despite intensive statin therapy. In a pre-specified analysis, we assessed the effects of alirocumab on types of MI. Methods and results  Median follow-up was 2.8 years. Myocardial infarction types were prospectively adjudicated and classified. Of 1860 total MIs, 1223 (65.8%) were adjudicated as Type 1, 386 (20.8%) as Type 2, and 244 (13.1%) as Type 4. Few events were Type 3 (n = 2) or Type 5 (n = 5). Alirocumab reduced first MIs [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77–0.95; P = 0.003], with reductions in both Type 1 (HR 0.87, 95% CI 0.77–0.99; P = 0.032) and Type 2 (0.77, 0.61–0.97; P = 0.025), but not Type 4 MI. Conclusion  After ACS, alirocumab added to intensive statin therapy favourably impacted on Type 1 and 2 MIs. The data indicate for the first time that a lipid-lowering therapy can attenuate the risk of Type 2 MI. Low-density lipoprotein cholesterol reduction below levels achievable with statins is an effective preventive strategy for both MI types.For complete list of authors see http://dx.doi.org/10.1093/eurheartj/ehz299</p

Effect of alirocumab on mortality after acute coronary syndromes. An analysis of the ODYSSEY OUTCOMES randomized clinical trial

Background: Previous trials of PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitors demonstrated reductions in major adverse cardiovascular events, but not death. We assessed the effects of alirocumab on death after index acute coronary syndrome. Methods: ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was a double-blind, randomized comparison of alirocumab or placebo in 18 924 patients who had an ACS 1 to 12 months previously and elevated atherogenic lipoproteins despite intensive statin therapy. Alirocumab dose was blindly titrated to target achieved low-density lipoprotein cholesterol (LDL-C) between 25 and 50 mg/dL. We examined the effects of treatment on all-cause death and its components, cardiovascular and noncardiovascular death, with log-rank testing. Joint semiparametric models tested associations between nonfatal cardiovascular events and cardiovascular or noncardiovascular death. Results: Median follow-up was 2.8 years. Death occurred in 334 (3.5%) and 392 (4.1%) patients, respectively, in the alirocumab and placebo groups (hazard ratio [HR], 0.85; 95% CI, 0.73 to 0.98; P=0.03, nominal P value). This resulted from nonsignificantly fewer cardiovascular (240 [2.5%] vs 271 [2.9%]; HR, 0.88; 95% CI, 0.74 to 1.05; P=0.15) and noncardiovascular (94 [1.0%] vs 121 [1.3%]; HR, 0.77; 95% CI, 0.59 to 1.01; P=0.06) deaths with alirocumab. In a prespecified analysis of 8242 patients eligible for ≥3 years follow-up, alirocumab reduced death (HR, 0.78; 95% CI, 0.65 to 0.94; P=0.01). Patients with nonfatal cardiovascular events were at increased risk for cardiovascular and noncardiovascular deaths (P<0.0001 for the associations). Alirocumab reduced total nonfatal cardiovascular events (P<0.001) and thereby may have attenuated the number of cardiovascular and noncardiovascular deaths. A post hoc analysis found that, compared to patients with lower LDL-C, patients with baseline LDL-C ≥100 mg/dL (2.59 mmol/L) had a greater absolute risk of death and a larger mortality benefit from alirocumab (HR, 0.71; 95% CI, 0.56 to 0.90; Pinteraction=0.007). In the alirocumab group, all-cause death declined wit h achieved LDL-C at 4 months of treatment, to a level of approximately 30 mg/dL (adjusted P=0.017 for linear trend). Conclusions: Alirocumab added to intensive statin therapy has the potential to reduce death after acute coronary syndrome, particularly if treatment is maintained for ≥3 years, if baseline LDL-C is ≥100 mg/dL, or if achieved LDL-C is low. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01663402

Theoretical study on electronic, optical, magnetic and photocatalytic properties of codoped SrTiO3 for green energy application

Motivated by the large scientific interest in development of double cation doping of SrTiO3 (STO) within the last years aiming to improve the water-splitting activity, electronic and ionic conductivity of STO, we study the effect of (La, X) and (Y, M) codoping (X = Al/Sc/Cr/Mn/Fe/Co/Ni/Mo, and M = Al/Cr/Mo) on the structure, electronic, magnetic, optical and photocatalytic properties (for water-splitting and CO2 reduction) of STO using spin-polarized hybrid density functional theory. In most considered cases, the X and M monodoping reduces the bandgap of STO more than the (La, X) and (Y, M) codoping, except for the case of (La, Ni) codoping. We found out La-/Y-doping, and (La/Y, Al)-/(La, Sc)-codoping cannot improve the conductivity of STO, while other monodopants and codopants can increase it. Our calculations have revealed that the best suited candidates for mono-/co-doped STO-based photocatalysts are Fe-/(La, Ni)-STO. Furthermore, we disclosed Fe-/Mn-/(La, Mn/Fe/Ni)-STO could be appropriate for spintronic applications

Unravelling the interplay of geometrical, magnetic and electronic properties of metal-doped graphene nanomeshes

Graphene nanomeshes (GNMs), formed by creating a superlattice of pores in graphene, possess rich physical and chemical properties. Many of these properties are determined by the pore geometry. In this work, we use first principles calculations to study the magnetic and electronic properties of metal-doped nitrogen-passivated GNMs. We find that the magnetic behaviour is dependent on the pore shape (trigonal vs. hexagonal) as dictated by the number of covalent bonds formed between the 3$d$ metal and the passivating N atoms. We also find that Cr and V doped trigonal-pore GNMs, and Ti doped GNMs are the most favourable for spintronic applications. The calculated magnetic properties of Fe-doped GNMs compare well with recent experimental observations. The studied systems are useful as spin filters and chemical sensors.Comment: 14 pages (preprint style), 4 figure