Interfacial electron transfer dynamics of photosensitized zinc oxide nanoclusters

The authors have prepared and characterized photosensitized zinc oxide (ZnO) nanoclusters, dispersed in methanol, using carboxylated coumarin dyes for surface adsorption. Femtosecond time-resolved emission spectroscopy allows the authors to measure the photo-induced charge carrier injection rate constant from the adsorbed photosensitizer to the n-type semiconductor nanocluster. These results are compared with other photosensitized semiconductors

Photoreductive dechlorination of chlorinated benzene derivatives catalyzed by ZnS nanocrystallites

ZnS nanocrystallites effectively enhanced photo-reduction of chlorinated benzene derivatives in the presence of triethylamine as a sacrificial electron donor under UV irradiation (l > 300 nm), leading to selective and stepwise dechlorination to give benzene at the final stage. Photochemical detoxification of halogenated compounds, such as PCB, dioxin, and DDT, has been attracting much attention because this can be regarded as a promising process to eliminate C-Cl bonds under environmentally relevant and mild conditions. In particular, TiO 2 -catalyzed photoprocesses involving oxidation and reduction in aqueous systems have been extensively investigated. 1 In such systems, however, photooxidation proceeds through the formation of hydroxyl radical (HO•), leading to unavoidable formation of unknown photoproducts especially from polychlorinated compounds. 2,3 Further, the rate of such photodegradation often slows in the case of polychlorinated compounds because they are electron-deficient molecules, i.e. their oxidation potentials are very positive in nature, showing resistance to the electrophilic attack of HO•. A DMF solution of ZnS nanocrystallites was prepared by the reaction of Zn(ClO 4 ) 2 with H 2 S under cooling with ice and water as described elsewhere. 7 Photoreactions were carried out under cooling with water by UV irradiation of a DMF solution (2 ml) containing a substrate (25 mM), ZnS nanocrystallites (2.5 mM in diatomic concentration as ZnS) and triethylamine (TEA, 1 M) in a Pyrex glass tube using a 500 W high pressure mercury lamp. The reaction mixtures were analyzed by gas chromatography with a fused silica capillary column (HiCap-CBP20, 25 m 3 0.2 mm, Shimadzu) using dodecane as an internal standard. The dechlorination proceeded at a relatively high rate even without ZnS nanocrystallites. The absorption spectrum measured for the mixture of 1,4-dichlorobenzene and TEA showed the appearance of a shoulder at the long wavelength edge of the absorption of 1,4-dichlorobenzene, suggesting the formation of the exciplex between the two compounds. The formation of the exciplex should contribute to the photochemical dechlorination without the catalyst. In our earlier report, ZnS nanocrystallites prepared in DMF act as a photocatalyst for the two-electron reduction of CO 2 to HCOOH or CO in the presence of triethylamine

Canagliflozin and Cardiovascular and Renal Outcomes in Type 2 Diabetes Mellitus and Chronic Kidney Disease in Primary and Secondary Cardiovascular Prevention Groups

Background: Canagliflozin reduces the risk of kidney failure in patients with type 2 diabetes mellitus and chronic kidney disease, but effects on specific cardiovascular outcomes are uncertain, as are effects in people without previous cardiovascular disease (primary prevention). Methods: In CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation), 4401 participants with type 2 diabetes mellitus and chronic kidney disease were randomly assigned to canagliflozin or placebo on a background of optimized standard of care. Results: Primary prevention participants (n=2181, 49.6%) were younger (61 versus 65 years), were more often female (37% versus 31%), and had shorter duration of diabetes mellitus (15 years versus 16 years) compared with secondary prevention participants (n=2220, 50.4%). Canagliflozin reduced the risk of major cardiovascular events overall (hazard ratio [HR], 0.80 [95% CI, 0.67-0.95]; P=0.01), with consistent reductions in both the primary (HR, 0.68 [95% CI, 0.49-0.94]) and secondary (HR, 0.85 [95% CI, 0.69-1.06]) prevention groups (P for interaction=0.25). Effects were also similar for the components of the composite including cardiovascular death (HR, 0.78 [95% CI, 0.61-1.00]), nonfatal myocardial infarction (HR, 0.81 [95% CI, 0.59-1.10]), and nonfatal stroke (HR, 0.80 [95% CI, 0.56-1.15]). The risk of the primary composite renal outcome and the composite of cardiovascular death or hospitalization for heart failure were also consistently reduced in both the primary and secondary prevention groups (P for interaction >0.5 for each outcome). Conclusions: Canagliflozin significantly reduced major cardiovascular events and kidney failure in patients with type 2 diabetes mellitus and chronic kidney disease, including in participants who did not have previous cardiovascular disease

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Computational Verification of So-Called Perovskite Solar Cells as PbI_6^<4−> -Aligned Solar Cells

Effective sensitizing components in so-called perovskite solar cells (PSC) are lead hexaiodide (PbI_6^) salts of PbI_6^ (MeNH_3^+)n (n = 2∼4). Density-functional-theory-based molecular modeling (DFT/MM) of X-ray crystalline structure of PbI_6^/MeNH_3^+ salt (FOLLIB) verifies that the packing unit of FOLLIB has UV/Vis absorption spectrum at λmax = 424 nm, giving pale yellow color as complementary color. DFT/MM of the horizontal component in the FOLLIB gives narrow energy gap of 0.3 eV, verifying remarkable semiconducting property through tight alignments of PbI_6^ components coupled with MeNH_3^+. DFT/MM of the central PbI_6^/MeNH_3^+ components verifies that the central component has UV/Vis absorption spectra with respective λmax = 570 nm, λmax = 762 nm and λmax = 945 nm, and plays an essential role as panchromatic sensitizers. In addition, their equilibrium geometric structures show slightly hypsochromic UV/Vis absorption spectra at respective λmax = 486 nm, λmax = 560 nm, and λmax = 563 nm as results of migration of MeNH_3^+ close to PbI_6^. DFT/MM also verifies that PbI_6^ components align tightly to nanocrystalline TiO_2 (nc-TiO_2) and to spiro-OMeTAD in PSC through electron density induced by van der Waals interaction. Electron density-based alignments of PbI_6^ components well explain unidirectional and leakage-free electron diffusion leading to high open-circuit voltage in PbI_6^-aligned solar cells. At the same time, the semiconducting and panchromatic sensitizing layer of PbI_6^/MeNH_3^+ components contribute to excellent short-circuit photocurrent of PbI_6^-aligned solar cells

Quantum chemistry molecular modeling for radio-frequency and microwave- frequency thermo-upconversion heating of metal oxides of NiO and Fe2O3

[EN] Under irradiance of 1kW-MW, nickel oxide (Ni(II)O, 25 gr)) can heat up to 1,300°C in 6 min, while ferric oxide (Fe(III)2O3, 25gr) up to 88°C in 30 min. Since Ni(II) and Fe(III) have unpaired electron (spin) of respective 2 and 5, the big difference in the MW heating speed must be explained by thermo-upconversion mechanism as recently verified for quick MW heating of water clusters.1) MW heating power by magnetic loss factor of magnetic metal oxides with unpaired electron, i.e., spin dcould not rationalize such heating-speed and temperature difference. Density functional theory-based molecular modeling(DFT/MM, B3LYP, 6-31G*) of NiO-tetramer of [(NiO)2]2 is successfully carried out with negative heat of formation, giving effective absorption in both FIR and IR regions, which verifies that Ni(II)O should be heated up through thermo-upconversion to the IR region via radio-, MW- and FIR-absorption, i.e., FIR/IR absorption and thermal IR dissipationYanagida, S.; Matsumura, T. (2019). Quantum chemistry molecular modeling for radio-frequency and microwave- frequency thermo-upconversion heating of metal oxides of NiO and Fe2O3. En AMPERE 2019. 17th International Conference on Microwave and High Frequency Heating. Editorial Universitat Politècnica de València. 9-12. https://doi.org/10.4995/AMPERE2019.2019.10234OCS91