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NASA's New Horizons mission unveiled a diverse landscape of Pluto's surface with massive regions being neutral in color, while others like Cthulhu Macula range from golden-yellow to reddish comprising up to half of Pluto's carbon budget. Here, we demonstrate in laboratory experiments merged with electronic structure calculations that the photolysis of solid acetylene – the most abundant precipitate on Pluto's surface – by low energy ultraviolet photons efficiently synthesizes benzene and polycyclic aromatic hydrocarbons via excited state photochemistry thus providing critical molecular building blocks for the colored surface material. Since low energy photons deliver doses to Pluto's surface exceeding those from cosmic rays by six orders of magnitude, these processes may significantly contribute to the coloration of Pluto's surface and of hydrocarbon-covered surfaces of Solar System bodies such as Triton in general. This discovery critically enhances our perception of the distribution of aromatic molecules and carbon throughout our Solar System. 

The photophysical properties of naturally occurring chlorophylls depend on the regioisomeric nature of the β-pyrrolic substituents. Such systems are the “gold standard” by which such effects are judged. However, simple extrapolations from what has been learned with chlorophylls may not be appropriate for other partially reduced porphyrinoids. Here we report the synthesis of a series of cis / trans -porphodilactones ( cis / trans -1) and related derivatives ( cis / trans 2–5) designed to probe the effect of regioisomeric substitution in porphyrinoids that incorporate degrees of unsaturation through the β-pyrrolic periphery that exceed those of chlorophyll. These test systems were obtained through β-pyrrolic modifications of the tetrapyrrolic core, which included reduction of β-diazalone to the corresponding dilactol moieties and 1,3-dipolar cycloadditions. In the case of cis - vs. trans -3 bearing two pyrrolidine-fused β-rings we found an unprecedented Δ Q L up to ca. 71 nm (2086 cm −1 ), where Δ Q L ( Q L means the lowest energy transfer band, also the S 0 → S 1 transition band, which is often assigned as Q y (0,0) band) refers to the transition energy difference between the corresponding cis / trans -isomers. The Δ Q L values for these and other systems reported here were found to depend on the differences in the HOMO–LUMO energy gap and to be tied to the degeneracy and energy level splitting of the FMOs, as inferred from a combination of MCD spectral studies and DFT calculations. The aromaticity, estimated from the chemical shifts of the N–H protons and supported by theoretical calculations ( e.g. , AICD plots and NICS(1) values), was found to correlate with the extent of porphyrin periphery saturation resulting from the specific β-modifications. The aromaticity proved inversely proportional to the degree to which the regioisomerism affected the photophysical properties as noted from plots of Δ Q L s in cm −1 vs. the average NICS(1) values for 1–5. Such a finding is not something that can be easily interpolated from prior work and thus reveals how aromaticity may be used to fine-tune photophysical effects in reduced porphyrinoids. 

Glucocorticoids and asparaginase, used to treat acute lymphoblastic leukemia (ALL), can cause hypertriglyceridemia. We compared triglyceride levels, risk factors, and associated toxicities in two ALL trials at St. Jude Children's Research Hospital with identical glucocorticoid regimens, but different asparaginase formulations. In Total XV (TXV), nativeEscherichia colil‐asparaginase was front‐line therapy versus the pegylated formulation (PEG‐asparaginase) in Total XVI (TXVI).

Patients enrolled on TXV (n = 498) and TXVI (n = 598) were assigned to low‐risk (LR) or standard/high‐risk (SHR) treatment arms (ClinicalTrials.gov identifiers: NCT00137111 and NCT00549848). Triglycerides were measured four times and were evaluable in 925 patients (TXV:n = 362; TXVI:n = 563). The genetic contribution was assessed using a triglyceride polygenic risk score (triglyceride‐PRS). Osteonecrosis, thrombosis, and pancreatitis were prospectively graded.

The largest increase in triglycerides occurred in TXVI SHR patients treated with dexamethasone and PEG‐asparaginase (4.5‐fold increase;P <1 × 10⁻¹⁵). SHR patients treated with PEG‐asparaginase (TXVI) had more severe hypertriglyceridemia (>1000 mg/dL) compared to nativel‐asparaginase (TXV): 10.5% versus 5.5%, respectively (P = .007). At week 7, triglycerides did not increase with dexamethasone treatment alone (LR patients) but did increase with dexamethasone plus asparaginase (SHR patients). The variability in triglycerides explained by the triglyceride‐PRS was highest at baseline and declined with therapy. Hypertriglyceridemia was associated with osteonecrosis (P = .0006) and thrombosis (P = .005), but not pancreatitis (P = .4).

Triglycerides were affected more by PEG‐asparaginase than nativel‐asparaginase, by asparaginase more than dexamethasone, and by drug effects more than genetics. It is not clear whether triglycerides contribute to thrombosis and osteonecrosis or are biomarkers of the toxicities.