Synthesis and characterization of C60 and C70 acetylacetone monoadducts and study of their photochemical properties for potential application in solar cells

We report on the synthesis of C60 and C70 monoadducts at room temperature through the Bingel reaction; employing acetylacetone as ligand; in presence of DBU (1,8-Diazabicyclo [5.4.0] undec-7-ene), carbon tetrabromide (CBr4), and o-dichlorobenzene. Diacetylmethane-[C60-Ih]-fullerene-[5,6] and diacetylmethane-[C70-D5h]-fullerene-[5,6] monoadducts were obtained with yields of 69% and 44%, respectively. The products were purified by column chromatography (CC, on silica gel, using hexane, carbon disulfide, and chloroform as eluents at room temperature) and characterized by Nuclear Magnetic Resonance (1H and 13C), Fourier-Transform Infrared (FT-IR) and UV-Visible spectroscopies, Matrix-assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) Mass spectrometry, Cyclic Voltammetry (CV), and Osteryoung Square Wave Voltammetry (OSWV). Both compounds showed irreversible reduction peaks controlled by diffusion, with LUMO energy levels of -3.09 eV, -3.13 eV for C60, and C70 monoadducts, respectively. These values are comparable with the -3.99 eV of PC61BM. The synthetized adducts were incorporated into inverted-type perovskite solar cells and were used as electron transporting materials (ETM) obtaining power conversion efficiencies (PCE) of 8.5% and 14.0% for the C60 and C70 monoadducts, respectively. When C60 is replaced by a lower symmetrical fullerene such as C70 an improved light absorption in the visible region is observed.

The Physiological Implications of S-Nitrosoglutathione Reductase (GSNOR) Activity Mediating NO Signalling in Plant Root Structures

Nitrogen remains an important macronutrient in plant root growth due to its application in amino acid production, in addition to its more elusive role in cellular signalling through nitric oxide (NO). NO is widely accepted as an important signalling oxidative radical across all organisms, leading to its study in a wide range of biological pathways. Along with its more stable NO donor, S-nitrosoglutathione (GSNO), formed by NO non-enzymatically in the presence of glutathione (GSH), NO is a redox-active molecule capable of mediating target protein cysteine thiols through the post translational modification, S-nitrosation. S-nitrosoglutathione reductase (GSNOR) thereby acts as a mediator to pathways regulated by NO due to its activity in the irreversible reduction of GSNO to oxidized glutathione (GSSG) and ammonia. GSNOR is thought to be pleiotropic and often acts by mediating the cellular environment in response to stress conditions. Under optimal conditions its activity leads to growth by transcriptional upregulation of the nitrate transporter, NRT2.1, and through its interaction with phytohormones like auxin and strigolactones associated with root development. However, in response to highly nitrosative and oxidative conditions its activity is often downregulated, possibly through an S-nitrosation site on GSNOR at cys271, Though GSNOR knockout mutated plants often display a stunted growth phenotype in all structures, they also tend to exhibit a pre-induced protective effect against oxidative stressors, as well as an improved immune response associated with NO accumulation in roots.

Agricultural managed aquifer recharge — water quality factors to consider

The resilience and productivity of California's agriculture is threatened by groundwater overdraft, reduction in aquifer water quality, increased land subsidence damage to infrastructure and an irreversible reduction in groundwater storage capacity. Intentionally flooding agricultural fields during winter — a practice referred to as agricultural managed aquifer recharge (AgMAR) — can help counteract overdraft. However, the potential for AgMAR to exacerbate nitrate/salt leaching and contamination of at-risk aquifers remains a critical concern. To quantify the risk of groundwater contamination with AgMAR, we took 30-foot-long soil cores in 12 almond orchards, processing tomato fields and wine grape vineyards on low- and high-permeability soils, measured nitrate and total dissolved solids concentrations and calculated stored nitrate-N. Wine grape vineyards on permeable soils had the least nitrate leaching risk observed. However, almond orchards and tomato fields could be leveraged for AgMAR if dedicated recharge sites were established and clean surface water used for recharge. Historical land use, current nitrogen management and soil permeability class are the main factors to consider before implementing AgMAR.

Triapine Derivatives Act as Copper Delivery Vehicles to Induce Deadly Metal Overload in Cancer Cells

Thiosemicarbazones continue to attract the interest of researchers as potential anticancer drugs. For example, 3-aminopyridine-2-carboxaldehyde thiosemicarbazone, or triapine, is the most well-known representative of this class of compounds that has entered multiple phase I and II clinical trials. Two new triapine derivatives HL1 and HL2 were prepared by condensation reactions of 2-pyridinamidrazone and S-methylisothiosemicarbazidium chloride with 3-N-(tert-butyloxycarbonyl) amino-pyridine-2-carboxaldehyde, followed by a Boc-deprotection procedure. Subsequent reaction of HL1 and HL2 with CuCl2·2H2O in 1:1 molar ratio in methanol produced the complexes [CuII(HL1)Cl2]·H2O (1·H2O) and [CuII(HL2)Cl2] (2). The reaction of HL2 with Fe(NO3)3∙9H2O in 2:1 molar ratio in the presence of triethylamine afforded the complex [FeIII(L2)2]NO3∙0.75H2O (3∙0.75H2O), in which the isothiosemicarbazone acts as a tridentate monoanionic ligand. The crystal structures of HL1, HL2 and metal complexes 1 and 2 were determined by single crystal X-ray diffraction. The UV-Vis and EPR spectroelectrochemical measurements revealed that complexes 1 and 2 underwent irreversible reduction of Cu(II) with subsequent ligand release, while 3 showed an almost reversible electrochemical reduction in dimethyl sulfoxide (DMSO). Aqueous solution behaviour of HL1 and 1, as well as of HL2 and its complex 2, was monitored as well. Complexes 1−3 were tested against ovarian carcinoma cells, as well as noncancerous embryonic kidney cells, in comparison to respective free ligands, triapine and cisplatin. While the free ligands HL1 and HL2 were devoid of antiproliferative activity, their respective metal complexes showed remarkable antiproliferative activity in a micromolar concentration range. The activity was not related to the inhibition of ribonucleotide reductase (RNR) R2 protein, but rather to cancer cell homeostasis disturbance—leading to the disruption of cancer cell signalling.

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

Two novel carbazole-based compounds 7a and 7b were synthesised as potential candidates for application in organic electronics. The materials were fully characterised by NMR spectroscopy, mass spectrometry, FTIR, thermogravimetric analysis, differential scanning calorimetry, cyclic voltammetry, and absorption and emission spectroscopy. Compounds 7a and 7b, both of which were amorphous solids, were stable up to 291 °C and 307 °C, respectively. Compounds 7a and 7b show three distinctive absorption bands: high and mid energy bands due to locally excited (LE) transitions and low energy bands due to intramolecular charge transfer (ICT) transitions. In dichloromethane solutions compounds 7a and 7b gave emission maxima at 561 nm and 482 nm with quantum efficiencies of 5.4% and 97.4% ± 10%, respectively. At positive potential, compounds 7a and 7b gave two different oxidation peaks, respectively: quasi-reversible at 0.55 V and 0.71 V, and reversible at 0.84 V and 0.99 V. At negative potentials, compounds 7a and 7b only exhibited an irreversible reduction peak at −1.86 V and −1.93 V, respectively.

Synthesis of novel multifunctional carbazole based molecules and their thermal, electrochemical and optical properties

Two novel carbazole-based compounds 7a and 7b were synthesised as potential candidates for application in organic electronics. The materials were fully characterised by NMR spectroscopy, mass spectrometry, FT-IR, thermogravimetric analysis, differential scanning calorimetry, cyclic voltammetry, and absorption and emission spectroscopy. Compounds 7a and 7b, both of which were amorphous solids, were stable up to 291oC and 307oC, respectively. Compounds 7a and 7b show three distinctive absorption bands: high and mid energy bands due to locally excited (LE) transitions and low energy bands due to intramolecular charge transfer (ICT) transitions. In dichloromethane solutions compounds 7a and 7b gave emission maxima at 561 nm and 482 nm with quantum efficiencies of 5.4% and 97.4% ± 10%, respectively. At positive potential, compounds 7a and 7b gave two different oxidation peaks, respectively: quasi-reversible at 0.55 V and 0.71 V, and reversible at 0.84 V and 0.99 V. At negative potentials, compounds 7a and 7b only exhibited an irreversible reduction peak at -1.86 V and -1.93 V, respectively.

Effects of vocal training in a musicophile with congenital amusia

Congenital amusia is a condition in which an individual suffers from a deficit of musical pitch perception and production. Individuals suffering from congenital amusia generally tend to abstain from musical activities. Here, we present the unique case of Tim Falconer, a self-described musicophile who also suffers from congenital amusia. We describe and assess Tim’s attempts to train himself out of amusia through a self-imposed 18-month program of formal vocal training and practice. We tested Tim with respect to music perception and vocal production across seven sessions including pre- and post-training assessments. We also obtained diffusion-weighted images of his brain to assess connectivity between auditory and motor planning areas via the arcuate fasciculus (AF). Tim’s behavioral and brain data were compared to that of normal and amusic controls. While Tim showed temporary gains in his singing ability, he did not reach normal levels, and these gains faded when he was not engaged in regular lessons and practice. Tim did show some sustained gains with respect to the perception of musical rhythm and meter. We propose that Tim’s lack of improvement in pitch perception and production tasks is due to long-standing and likely irreversible reduction in connectivity along the AF fiber tract.

A REVIEW ON THE EFFECT OF FEBUXOSTAT IN CHRONIC KIDNEY PATIENTS, IT’S SIGNIFICANCE IN eGFR, URIC ACID AND ALBUMINURIA.

Chronic kidney disease is defined as the abnormality of the kidney structure or function for≥ 3 months and is associated with an irreversible reduction of the excretory and the endocrine functions of the kidney. An important risk factor for the development and progression of CKD is hyperuricemia. Hyperuricemia can occur as a result of the increased production or the reduced secretion of uric acid. Increased uric acid level is significantly associated with a greater decline in renal function and there is a higher risk of progression into kidney failure. Febuxostat is a nonpurine xanthine oxidase inhibitor for the treatment of hyperuricemia in patients with chronic kidney disease. It reduces serum uric acid concentrations by blocking the transformation of hypoxanthine to xanthine and xanthine to uric acid. Febuxostat is mainly metabolized in the liver and excreted through both urine and feces. Renal adjustment is also not required in CKD patients with mild to moderately reduced eGFR as it is metabolized mainly by glucuronidation and oxidation in the liver and well excreted by both urinary and fecal routes. Recent studies show that, in addition to lowering the uric acid level, febuxostat preserves the eGFR. Keywords: Chronic kidney disease, hyperuricemia, febuxostat, eGFR

Characterization of a Carbonyl Reductase from Rhodococcus erythropolis WZ010 and Its Variant Y54F for Asymmetric Synthesis of (S)-N-Boc-3-Hydroxypiperidine

The recombinant carbonyl reductase from Rhodococcus erythropolis WZ010 (ReCR) demonstrated strict (S)-stereoselectivity and catalyzed the irreversible reduction of N-Boc-3-piperidone (NBPO) to (S)-N-Boc-3-hydroxypiperidine [(S)-NBHP], a key chiral intermediate in the synthesis of ibrutinib. The NAD(H)-specific enzyme was active within broad ranges of pH and temperature and had remarkable activity in the presence of higher concentration of organic solvents. The amino acid residue at position 54 was critical for the activity and the substitution of Tyr54 to Phe significantly enhanced the catalytic efficiency of ReCR. The kcat/Km values of ReCR Y54F for NBPO, (R/S)-2-octanol, and 2-propanol were 49.17 s−1 mM−1, 56.56 s−1 mM−1, and 20.69 s−1 mM−1, respectively. In addition, the (S)-NBHP yield was as high as 95.92% when whole cells of E. coli overexpressing ReCR variant Y54F catalyzed the asymmetric reduction of 1.5 M NBPO for 12 h in the aqueous/(R/S)-2-octanol biphasic system, demonstrating the great potential of ReCR variant Y54F for practical applications.