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Objectives: Although hemispheric surgeries are among the most effective procedures for drug‐resistant epilepsy (DRE) in the pediatric population, there is a large variability in seizure outcomes at the group level. A recently developed HOPS score provides individualized estimation of likelihood of seizure freedom to complement clinical judgement. The objective of this study was to develop a freely accessible online calculator that accurately predicts the probability of seizure freedom for any patient at 1‐, 2‐, and 5‐years post‐hemispherectomy. Methods: Retrospective data of all pediatric patients with DRE and seizure outcome data from the original Hemispherectomy Outcome Prediction Scale (HOPS) study were included. The primary outcome of interest was time‐to‐seizure recurrence. A multivariate Cox proportional‐hazards regression model was developed to predict the likelihood of post‐hemispheric surgery seizure freedom at three time points (1‐, 2‐ and 5‐ years) based on a combination of variables identified by clinical judgment and inferential statistics predictive of the primary outcome. The final model from this study was encoded in a publicly accessible online calculator on the International Network for Epilepsy Surgery and Treatment (iNEST) website (https://hops‐calculator.com/). Results: The selected variables for inclusion in the final model included the five original HOPS variables (age at seizure onset, etiologic substrate, seizure semiology, prior non‐hemispheric resective surgery, and contralateral fluorodeoxyglucose–positron emission tomography [FDG‐PET] hypometabolism) and three additional variables (age at surgery, history of infantile spasms, and magnetic resonance imaging [MRI] lesion). Predictors of shorter time‐to‐seizure recurrence included younger age at seizure onset, prior resective surgery, generalized seizure semiology, FDG‐PET hypometabolism contralateral to the side of surgery, contralateral MRI lesion, non‐lesional MRI, non‐stroke etiologies, and a history of infantile spasms. The area under the curve (AUC) of the final model was 73.0%. Significance: Online calculators are useful, cost‐free tools that can assist physicians in risk estimation and inform joint decision‐making processes with patients and families, potentially leading to greater satisfaction. Although the HOPS data was validated in the original analysis, the authors encourage external validation of this new calculator. [ABSTRACT FROM AUTHOR]

Catalytic acylation of organohalides with aldehydes is an ideal strategy for the direct synthesis of ketones. However, the utilization of unactivated alkyl halides in such a transformation remains a formidable challenge. In this study, we developed a cross‐coupling reaction of aldehydes with unactivated alkyl halides through N‐heterocyclic carbene catalysis. With this protocol, various ketones could be rapidly synthesized from readily available starting materials under mild conditions. This organocatalytic system was successfully applied in the late‐stage functionalization of pharmaceutical derivatives. Mechanistic investigations suggest a closed‐shell nucleophilic substitution mechanism for this reaction. [ABSTRACT FROM AUTHOR]

The effectiveness of neoadjuvant immune checkpoint inhibitor (ICI) therapy is confirmed in clinical trials; however, the patients suitable for receiving this therapy remain unspecified. Previous studies have demonstrated that the tumor microenvironment (TME) dominates immunotherapy; therefore, an effective TME classification strategy is required. In this study, five crucial immunophenotype‐related molecules (WARS, UBE2L6, GZMB, BATF2, and LAG‐3) in the TME are determined in five public gastric cancer (GC) datasets (n = 1426) and an in‐house sequencing dataset (n = 79). Based on this, a GC immunophenotypic score (IPS) is constructed using the least absolute shrinkage and selection operator (LASSO) Cox, and randomSurvivalForest. IPSLow is characterized as immune‐activated, and IPSHigh is immune‐silenced. Data from seven centers (n = 1144) indicate that the IPS is a robust and independent biomarker for GC and superior to the AJCC stage. Furthermore, patients with an IPSLow and a combined positive score of ≥5 are likely to benefit from neoadjuvant anti‐PD‐1 therapy. In summary, the IPS can be a useful quantitative tool for immunophenotyping to improve clinical outcomes and provide a practical reference for implementing neoadjuvant ICI therapy for patients with GC. [ABSTRACT FROM AUTHOR]

Radical N‐heterocyclic carbene (NHC) organocatalysis has progressed significantly in recent years, enabling various incredible transformations. However, prefunctionalized substrates bearing a redox functionality were always required. As a result, the direct functionalization of aliphatic C−H bonds in simple substrates remains a challenge. This situation was changed once the hydrogen transfer atom (HAT) strategy was successfully applied in radical NHC catalysis very recently. This concept paper focused on the discussion of merging NHC catalysis with a classical intramolecular 1,5‐HAT process. Moreover, the unprecedented application of intermolecular HAT in radical NHC catalysis is highlighted as a novel catalysis model showing great synthetic promise. [ABSTRACT FROM AUTHOR]

Objectives: Elevated thioredoxin‐interacting protein (TXNIP)‐induced pyroptosis contributes to the pathology of diabetic kidney disease (DKD). However, the molecular mechanisms in dysregulated TXNIP in DKD remain largely unclear. Materials and methods: Transcriptomic analysis identified a novel long noncoding RNA—Prader Willi/Angelman region RNA, SNRPN neighbour (PWARSN)—which was highly expressed in a proximal tubular epithelial cell (PTEC) under high glucose conditions. We focused on revealing the functions of PWARSN in regulating TXNIP‐mediated pyroptosis in PTECs by targeting PWARSN expression via lentivirus‐mediated overexpression and CRISPR‐Cas9‐based knockout in vitro and overexpressing PWARSN in the renal cortex by AAV‐9 targeted injection in vivo. A number of molecular techniques disclosed the mechanisms of PWARSN in regulating TXNIP induced‐pyroptosis in DKD. Results: TXNIP‐NOD‐like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome and PTEC pyroptosis were activated in the renal tubules of patients with DKD and in diabetic mice. Then we explored that PWARSN enhanced TXNIP‐driven PTECs pyroptosis in vitro and in vivo. Mechanistically, cytoplasmic PWARSN sponged miR‐372‐3p to promote TXNIP expression. Moreover, nuclear PWARSN interacted and facilitated RNA binding motif protein X‐linked (RBMX) degradation through ubiquitination, resulting in the initiation of TXNIP transcription by reducing H3K9me3‐enrichment at the TXNIP promoter. Further analysis indicated that PWARSN might be a potential biomarker for DKD. Conclusions: These findings illustrate distinct dual molecular mechanisms for PWARSN‐modulated TXNIP and PTECs pyroptosis in DKD, presenting PWARSN as a promising therapeutic target for DKD. [ABSTRACT FROM AUTHOR]

Oxidative N‐heterocyclic carbene (NHC) organocatalysis, typically leading to the formation of acyl azolium reactive intermediates, constitutes one of the most important activation strategies for the NHC‐catalyzed chemical transformations. Here, we report an unprecedented oxidative radical NHC catalysis by using peroxyester as the external single‐electron oxidant to realize divergent difunctionalization of olefins. The key to success of this chemistry is the catalytic generation of oxygen radicals that could trigger an intermolecular hydrogen atom transfer to activate the inert C−H bonds, thereby enabling the productive radical relay process. With this protocol, commonly used general chemicals could serve as radical precursors to allow efficient synthesis of value‐added products in a straightforward and cost‐effective manner. Preliminary mechanistic investigations, including control experiments and DFT calculations, shed light on the NHC organocatalytic radical reaction mechanism. [ABSTRACT FROM AUTHOR]

Summary: Selenium (Se) is an essential trace element in human health. In this article, egg white polypeptide (EWP) was used as the reducing agent and stabiliser to prepare a novel type of EWP‐selenium complex nanoparticles (EWP‐SeNPs). Particle size, morphology, FT‐IR, stability, and functional properties of EWP‐SeNPs were characterised. The results showed that EWP‐SeNPs were 30–50 nm in diameter and were spherical. The SeNPs complexed with the EWP through O‐ and N‐ containing groups. This reaction was entropy‐driven spontaneous and the binding force was mainly hydrophobic. The stability of EWP‐SeNPs was best at pH = 10. Moreover, EWP‐SeNPs showed significantly inhibitory effect on HepG‐2 cells in the range of 6.2500 to 50.0000 μg mL−1. Anti‐bacterial effect occurred when the concentration of EWP‐SeNPs was 1.2500 mg mL−1. This study would provide a green method for synthesising stable SeNPs, which was helpful for further evaluation in the food field. [ABSTRACT FROM AUTHOR]

Detailed textural and geochemical analyses of the carbonaceous achondrites Northwest Africa (NWA) 7680 and NWA 6962 support a rapid progression of thermal events, by similar processes, on the same parent body. The achondrites have olivine compositions of Fa44.8 and Fa47.4 for NWA 7680 and NWA 6962, respectively. Replicate oxygen isotope analyses of grains and bulk powders from NWA 7680 yielded average Δ17O values of −1.04 ± 0.03‰ and −1.00 ± 0.05‰, respectively, which is identical to that reported for NWA 6962. The whole rock ɛ54Cr compositions are also equivalent for NWA 7680 and NWA 6962 (1.36 ± 0.05 and 1.30 ± 0.05, respectively). Both meteorites are plagioclase‐rich, and NWA 7680 is also Fe‐metal‐rich, suggesting they both formed via differentiation processes that resulted in the pooling of partial melt products. Major element geochemical trends show that both rocks could be formed through the melting of chondritic material on a CR chondrite‐like parent body. This is consistent with oxygen isotope and chromium isotope compositions. Intrusion of a late‐stage melt is evident in both meteorites and the crystallization products include silica‐rich, alkali‐deficient nepheline. The late‐stage liquid has partially melted and mixed with primary plagioclase in NWA 6962. In contrast, the late‐stage liquid was often restricted to grain boundaries in NWA 7680, leaving some of the primary plagioclase crystals intact. In situ dating of NWA 7680 phosphate minerals (merrillite and fluorapatite) reveals that it has not experienced long duration thermal metamorphism, or impact‐related Pb loss and age resetting since 4578 ± 17 Ma (207Pb/206Pb age ± 2σ, within error of solar system age). Phosphates associated with the late‐stage melt in NWA 6962 yield a 207Pb/206Pb age of 4556.6 ± 8.0 Ma (2σ) within 2σ of the NWA 7680 age. These early dates indicate that the observed chromium isotope signatures in these meteorites were not introduced by a later high‐temperature event, such as late impact accretion processes. These data are consistent with a rapid separation of inner and outer solar system chemical reservoirs, planetesimal melting, differentiation, and cooling, all within several million years of calcium‐aluminum‐rich inclusion formation. [ABSTRACT FROM AUTHOR]

The direct functionalization of inert C(sp3)−H bonds under environmentally benign catalytic conditions remains a challenging task in synthetic chemistry. Here, we report an organocatalytic remote C(sp3)−H acylation of amides and cascade cyclization through a radical‐mediated 1,5‐hydrogen atom transfer mechanism using N‐heterocyclic carbene as the catalyst. Notably, a diversity of nitrogen‐containing substrates, including simple linear aliphatic carbamates and ortho‐alkyl benzamides, can be successfully applied to this organocatalytic system. With the established protocol, over 120 examples of functionalized δ‐amino ketones and isoquinolinones with diverse substituents were easily synthesized in up to 99 % yield under mild conditions. The robustness and generality of the organocatalytic strategy were further highlighted by the successful acylation of unactivated C(sp3)−H bonds and late‐stage modification of pharmaceutical molecules. Then, the asymmetric control of the radical reaction was attempted and proven feasible by using a newly designed chiral thiazolium catalyst, and moderate enantioselectivity was obtained at the current stage. Preliminary mechanistic investigations including several control reactions, KIE experiments, and computational studies shed light on the organocatalytic radical reaction mechanism. [ABSTRACT FROM AUTHOR]

The Cryogenian Period (717–635 Ma) experienced two low‐latitude "snowball Earth" glaciations, the Sturtian and the Marinoan of contrasting 57 and <16 Myr durations, respectively. A lack of reliable age controls on extensional tectonics and associated magmatic rocks during the Marinoan has hampered an understanding of the deglaciation. Furthermore, although deglaciation is generally assumed to have occurred once ongoing magmatism accumulated enough atmospheric CO2, as suggested by cap carbonates, specific geologic evidence linking volcanic events with deglaciation are lacking. Here, we present high‐precision zircon geochronology with chemical abrasion‐isotope‐dilution isotope ratio mass spectrometry that indicates an extensive and thick sequence of rift‐related magmatic rocks in South Qinling, Central China, erupted 2–6 Myr before the termination of the Marinoan. Climate modeling proposes a scenario explaining why the Marinoan was the shorter snowball and how volcanism may have driven the deglaciation. Plain Language Summary: Volcanic CO2 and dust emissions have been regarded as the major driver for Marinoan deglaciation. Most of CO2 outgassing is associated with seafloor spreading and subduction (arc magmatism), which are ongoing processes on geological timescales. To drastically increase CO2 emissions, there must have been many active rift zones during Marinoan glaciation. We provide age constraints on a previously little‐known major Marinoan rift‐related volcanic suite in South Qinling, which reveals volcanic activity lasting 4 Myr and ending 2 Myr before the termination of the Marinoan snowball Earth. Climate modeling provides constraints for the ice‐age duration deduced from the geological setting. Key Points: Volcanism is dated at 641–637 Ma using chemical abrasion‐isotope‐dilution isotope ratio mass spectrometry techniqueClimate modeling on the volcanism‐related CO2 emission is conductedEnhanced volcanic‐related dust and CO2 emission can shorten the Marinoan snowball Earth by 2–5 Myr [ABSTRACT FROM AUTHOR]

Objective: This study was undertaken to determine whether the vertical parasagittal approach or the lateral peri‐insular/peri‐Sylvian approach to hemispheric surgery is the superior technique in achieving long‐term seizure freedom. Methods: We conducted a post hoc subgroup analysis of the HOPS (Hemispheric Surgery Outcome Prediction Scale) study, an international, multicenter, retrospective cohort study that identified predictors of seizure freedom through logistic regression modeling. Only patients undergoing vertical parasagittal, lateral peri‐insular/peri‐Sylvian, or lateral trans‐Sylvian hemispherotomy were included in this post hoc analysis. Differences in seizure freedom rates were assessed using a time‐to‐event method and calculated using the Kaplan–Meier survival method. Results: Data for 672 participants across 23 centers were collected on the specific hemispherotomy approach. Of these, 72 (10.7%) underwent vertical parasagittal hemispherotomy and 600 (89.3%) underwent lateral peri‐insular/peri‐Sylvian or trans‐Sylvian hemispherotomy. Seizure freedom was obtained in 62.4% (95% confidence interval [CI] = 53.5%–70.2%) of the entire cohort at 10‐year follow‐up. Seizure freedom was 88.8% (95% CI = 78.9%–94.3%) at 1‐year follow‐up and persisted at 85.5% (95% CI = 74.7%–92.0%) across 5‐ and 10‐year follow‐up in the vertical subgroup. In contrast, seizure freedom decreased from 89.2% (95% CI = 86.3%–91.5%) at 1‐year to 72.1% (95% CI = 66.9%–76.7%) at 5‐year to 57.2% (95% CI = 46.6%–66.4%) at 10‐year follow‐up for the lateral subgroup. Log‐rank test found that vertical hemispherotomy was associated with durable seizure‐free progression compared to the lateral approach (p =.01). Patients undergoing the lateral hemispherotomy technique had a shorter time‐to‐seizure recurrence (hazard ratio = 2.56, 95% CI = 1.08–6.04, p =.03) and increased seizure recurrence odds (odds ratio = 3.67, 95% CI = 1.05–12.86, p =.04) compared to those undergoing the vertical hemispherotomy technique. Significance: This pilot study demonstrated more durable seizure freedom of the vertical technique compared to lateral hemispherotomy techniques. Further studies, such as prospective expertise‐based observational studies or a randomized clinical trial, are required to determine whether a vertical approach to hemispheric surgery provides superior long‐term seizure outcomes. [ABSTRACT FROM AUTHOR]

Indole‐based heterocycles containing sulfur or nitrogen atoms are important frameworks that occur widely in biological active natural products and drugs. Consequently, several novel chemical transformations and new catalytic strategies have been developed for the preparation of these skeletons in a highly efficient and selective manner. This review focuses on recent advancements in the construction of indole‐fused heterocyclic compounds by using iminoindolines, 3‐diazoindol‐2‐imines, 2‐thioxoindolines, and their derivatives as starting materials. [ABSTRACT FROM AUTHOR]

Objective: To develop and validate a model to predict seizure freedom in children undergoing cerebral hemispheric surgery for the treatment of drug‐resistant epilepsy. Methods: We analyzed 1267 hemispheric surgeries performed in pediatric participants across 32 centers and 12 countries to identify predictors of seizure freedom at 3 months after surgery. A multivariate logistic regression model was developed based on 70% of the dataset (training set) and validated on 30% of the dataset (validation set). Missing data were handled using multiple imputation techniques. Results: Overall, 817 of 1237 (66%) hemispheric surgeries led to seizure freedom (median follow‐up = 24 months), and 1050 of 1237 (85%) were seizure‐free at 12 months after surgery. A simple regression model containing age at seizure onset, presence of generalized seizure semiology, presence of contralateral 18‐fluoro‐2‐deoxyglucose–positron emission tomography hypometabolism, etiologic substrate, and previous nonhemispheric resective surgery is predictive of seizure freedom (area under the curve =.72). A Hemispheric Surgery Outcome Prediction Scale (HOPS) score was devised that can be used to predict seizure freedom. Significance: Children most likely to benefit from hemispheric surgery can be selected and counseled through the implementation of a scale derived from a multiple regression model. Importantly, children who are unlikely to experience seizure control can be spared from the complications and deficits associated with this surgery. The HOPS score is likely to help physicians in clinical decision‐making. [ABSTRACT FROM AUTHOR]

Asymmetric construction of pharmacologically interesting tetrahydrofuranyl spirooxindole frameworks has been achieved through organocatalytic [3+2] annulations of the readily available 3‐hydroxyoxindoles and pyrrolidone‐derived cyclic ketolactams. A variety of chiral spiro tetrahydrofuranyl products, which contain four contiguous stereocenters including two tetrasubstituted carbon centers, have been rapidly synthesized with remarkable results (up to 99% yield, >95:5 dr, and 99:1 er). Synthetic derivatization of the hemiketal moiety enables the installation of various halogen atoms into the structurally complex molecules in a stereospecific manner. Preliminary screening of anticancer bioactivity was performed, and 4 w showed obvious inhibitory capacity to the proliferation on a panel of cancer cell lines. [ABSTRACT FROM AUTHOR]

Mineral dust particles from different source regions typically have distinct Pb isotope ratios. Theoretically, Pb isotopic composition of terrigenous minerals isolated from open‐ocean sediments should allow for dust provenance reconstructions. However, Pb isotopes of terrigenous fractions of sediments have frequently been inconsistent with expected source region signatures. This study investigates the reason(s) for offsets between the Pb isotope values of the dust component in sediment cores and those expected from source regions with focus on changes in sediment composition, sediment age, and sediment processing for analysis. Pb isotope ratios from Pacific Ocean core‐top sediments show a general delineation of the Intertropical Convergence Zone (ITCZ). Isotope mixing models support these general trends, though similarity in Pb isotope ratios of disparate source regions makes constraining specific sources challenging. Pb isotope ratios in downcore samples varied on glacial/interglacial time scales, being less radiogenic during the last glacial maximum, suggesting either a weakened ITCZ or the addition of a new, less radiogenic, source to the system. Finally, Pb isotope ratios in some source region samples yielded different Pb isotope signatures in bulk source sample than in the insoluble terrigenous fraction of the source sample, indicating that differential mineral preservation within the terrigenous component in sediments may cause offsets from source signatures. Overall, while Pb isotopes show distinct basin‐scale variations, high‐resolution spatial reconstructions require tight age controls and consistency in analytical treatment if used to define ocean sediment source regions. Plain Language Summary: Dust deposited in the open ocean is sourced from rocks and sediment of various ages and location. The trace amounts of lead in this dust can have distinct isotopic values, theoretically allowing for reconstruction of dust sources. This paper looks at lead isotopes in dust deposited in the Pacific Ocean, specifically the Eastern Equatorial Pacific. Our objective is to understand how well this reconstruction tool works and if it can tell us how dust deposition has changed over glacial cycles. We found that lead isotopes work well to generally distinguish between Northern and Southern Hemisphere dust, though poor characterization and isotopic composition variability within smaller regions makes definitive source determination difficult. However, we did see changes over glacial climate cycles in the Eastern Equatorial Pacific, resulting from either change in wind patterns and/or the addition of a new dust source. Finally, we highlight the importance of consistent sample preparation to limit additional variability. Overall, lead isotopes can distinguish between some source trends, though work best when combined with other dust source tracers. Key Points: Pb isotopic ratios of detrital fractions provide general trends but not definitive determination of dust source regionsMixing models are sensitive to small changes in source isotopic values, highlighting importance of accurate source characterizationGlacial/Interglacial downcore variability in Pb isotopic ratios reflect climate‐driven dust delivery to the Eastern Equatorial Pacific [ABSTRACT FROM AUTHOR]

The June 2, 2018 impact of asteroid 2018 LA over Botswana is only the second asteroid detected in space prior to impacting over land. Here, we report on the successful recovery of meteorites. Additional astrometric data refine the approach orbit and define the spin period and shape of the asteroid. Video observations of the fireball constrain the asteroid's position in its orbit and were used to triangulate the location of the fireball's main flare over the Central Kalahari Game Reserve. Twenty‐three meteorites were recovered. A consortium study of eight of these classifies Motopi Pan as an HED polymict breccia derived from howardite, cumulate and basaltic eucrite, and diogenite lithologies. Before impact, 2018 LA was a solid rock of ~156 cm diameter with high bulk density ~2.85 g cm−3, a relatively low albedo pV ~ 0.25, no significant opposition effect on the asteroid brightness, and an impact kinetic energy of ~0.2 kt. The orbit of 2018 LA is consistent with an origin at Vesta (or its Vestoids) and delivery into an Earth‐impacting orbit via the ν6 resonance. The impact that ejected 2018 LA in an orbit toward Earth occurred 22.8 ± 3.8 Ma ago. Zircons record a concordant U‐Pb age of 4563 ± 11 Ma and a consistent 207Pb/206Pb age of 4563 ± 6 Ma. A much younger Pb‐Pb phosphate resetting age of 4234 ± 41 Ma was found. From this impact chronology, we discuss what is the possible source crater of Motopi Pan and the age of Vesta's Veneneia impact basin. [ABSTRACT FROM AUTHOR]

Over the past decades, N‐heterocyclic carbene (NHC) organocatalysis has undergone a flourish of development on the basis of closed‐shell reaction paths. By contrast, the emerging area of single‐electron transfer (SET) reactions enabled by NHC catalysis still remain underdeveloped, but offer plenty of opportunities to develop new catalytic modes and useful synthetic methods. A number of interesting transformations were triggered by the SET process from the electron‐rich Breslow intermediates to various single‐electron acceptors. In additions, recent studies revealed that the Breslow radical cations could also be generated by single‐electron reduction of the electron‐deficient acyl azolium intermediates. These discoveries open a new avenue for NHC organocatalysis to harness radical reactions. The present review will focus on the exciting advancements in the dynamic area of radical NHC organocatalysis. [ABSTRACT FROM AUTHOR]

The Hamburg meteorite fell on January 16, 2018, near Hamburg, Michigan, after a fireball event widely observed in the U.S. Midwest and in Ontario, Canada. Several fragments fell onto frozen surfaces of lakes and, thanks to weather radar data, were recovered days after the fall. The studied rock fragments show no or little signs of terrestrial weathering. Here, we present the initial results from an international consortium study to describe the fall, characterize the meteorite, and probe the collision history of Hamburg. About 1 kg of recovered meteorites was initially reported. Petrology, mineral chemistry, trace element and organic chemistry, and O and Cr isotopic compositions are characteristic of H4 chondrites. Cosmic ray exposure ages based on cosmogenic 3He, 21Ne, and 38Ar are ~12 Ma, and roughly agree with each other. Noble gas data as well as the cosmogenic 10Be concentration point to a small 40–60 cm diameter meteoroid. An 40Ar‐39Ar age of 4532 ± 24 Ma indicates no major impact event occurring later in its evolutionary history, consistent with data of other H4 chondrites. Microanalyses of phosphates with LA‐ICPMS give an average Pb‐Pb age of 4549 ± 36 Ma. This is in good agreement with the average SIMS Pb‐Pb phosphate age of 4535.3 ± 9.5 Ma and U‐Pb Concordia age of 4535 ± 10 Ma. The weighted average age of 4541.6 ± 9.5 Ma reflects the metamorphic phosphate crystallization age after parent body formation in the early solar system. [ABSTRACT FROM AUTHOR]

The efficient and enantioselective construction of cyclic compounds with a halogenated tetrasubstituted carbon through various catalytic strategies remains challenging. Thus, research on modern asymmetric catalysis is important. In this review, recent achievements that streamlined the synthesis of halogenated cyclic molecules through organocatalysis or transition‐metal catalysis were introduced. [ABSTRACT FROM AUTHOR]

Obesity and related metabolic disorders are associated with intestinal microbiota dysbiosis, disrupted intestinal barrier, and chronic inflammation. Neohesperidin (Neo), a natural polyphenol abundant in citrus fruits, is known for its preventative and therapeutic effects on numerous diseases. Here, we report that Neo administration attenuates weight gain, low-grade inflammation, and insulin resistance in mice fed high-fat diet (HFD). Also, Neo administration substantially restores gut barrier damage, metabolic endotoxemia, and systemic inflammation. Sequencing of 16S rRNA genes in fecal samples revealed that Neo administration reverses HFD-induced intestinal microbiota dysbiosis: an increase in the diversity of gut microbiota and alteration in the composition of intestinal microbiota (particularly in the relative abundances of Bacteroidetes and Firmicutes). Furthermore, systemic antibiotic treatment abolishes the beneficial effects of Neo in body weight control, suggesting that the effect of Neo on obesity attenuation largely depends on the gut microbiota. More importantly, we demonstrate that the impact of Neo on the regulation of obesity could be transferred from Neo-treated mice to HFD-fed mice via fecal microbiota transplantation. Collectively, our data highlight the efficacy of Neo as a prebiotic agent for attenuating obesity, implying a potential mechanism for gut microbiota mediated the beneficial effect of Neo. [ABSTRACT FROM AUTHOR]

Purpose: Patient‐controlled subcutaneous analgesia (PCSA) with sufentanil is an alternative analgesia strategy in patients with stage III‐IV cancer; however, its efficacy and safety have not been fully investigated. Methods: From May 10, 2017 to November 10, 2017, 120 patients with stage III‐IV cancer suffering from moderate to severe pain were prospectively enrolled from six hospitals and randomized to receive PCSA with morphine (control group) or sufentanil (intervention group). Before the PCSA and on days 1, 3, 7, 14, 28, and 56 after treatment, the numeric rating scale (NRS) and 36‐item Short Form health survey (SF‐36) were completed for each patient and the side effects were also recorded. RESULTS: No significant differences (P >.05) were observed in the preoperative NRS score and the SF‐36 parameters between the two groups. Patients in the intervention group achieved better pain relief, as indicated by lower NRS scores at days 14 (P =.040), 28 (P <.001), and 56 (P <.001) after PCSA device implantation (vs control group). Furthermore, the patients in the intervention group also achieved a better life quality, as indicated by the physical role, general health, social function body pain, and mental health scores. Finally, the patients receiving sufentanil showed lower levels of nausea and somnolence than those in the control group. Conclusion: PCSA with sufentanil achieves better pain control and life quality as well as fewer adverse reactions in stage III‐IV cancer patients with pain and may be a promising pain management in these patients. Trial registration: This study was registered at chictr.org.cn with the trial number: ChiCTR‐IPR‐17011280. [ABSTRACT FROM AUTHOR]

We report here a stereoselective [3+2] cyclization of 5‐alkenyl thiazolones and ketimines that allows the assembly of three diastereoisomers through the combination of stereodivergent organocatalysis and the following diastereoselective transformation of products. A broad spectrum of pyrrolidinyl spirooxindoles featuring stereochemical diversity has been synthesized through organocatalytic formal 1,3‐dipolar cycloadditions with up to 98% yield, >20:1 dr and 99:1 er. [ABSTRACT FROM AUTHOR]

Northwest Africa (NWA) 11042 is a heavily shocked achondrite with medium‐grained cumulate textures. Its olivine and pyroxene compositions, oxygen isotopic composition, and chromium isotopic composition are consistent with L chondrites. Sm‐Nd dating of its primary phases shows a crystallization age of 4100 ± 160 Ma. Ar‐Ar dating of its shocked mineral maskelynite reveals an age of 484.0 ± 1.5 Ma. This age coincides roughly with the breakup event of the L chondrite parent body evident in the shock ages of many L chondrites and the terrestrial record of fossil L chondritic chromite. NWA 11042 shows large depletions in siderophile elements (<0.01×CI) suggestive of a complex igneous history involving extraction of a Fe‐Ni‐S liquid on the L chondrite parent body. Due to its relatively young crystallization age, the heat source for such an igneous process is most likely impact. Because its mineralogy, petrology, and O isotopes are similar to the ungrouped achondrite NWA 4284 (this work), the two meteorites are likely paired and derived from the same parent body. [ABSTRACT FROM AUTHOR]

The trajectory and orbit of the LL7 ordinary chondrite Dishchii'bikoh are derived from low‐light video observations of a fireball first detected at 10:56:26 UTC on June 2, 2016. Results show a relatively steep ~21° inclined orbit and a short 1.13 AU semimajor axis. Following entry in Earth's atmosphere, the meteor luminosity oscillated corresponding to a meteoroid spin rate of 2.28 ± 0.02 rotations per second. A large fragment broke off at 44 km altitude. Further down, mass was lost to dust during flares at altitudes of 34, 29, and 25 km. Surviving meteorites were detected by Doppler weather radar and several small 0.9–29 g meteorites were recovered under the radar reflection footprint. Based on cosmogenic radionuclides and ground‐based radiometric observations, the Dishchii'bikoh meteoroid was 80 ± 20 cm in diameter assuming the density was 3.5 g/cm3. The meteoroid's collisional history confirms that the unusual petrologic class of LL7 does not require a different parent body than three previously observed LL chondrite falls. Dishchii'bikoh was ejected 11 Ma ago from parent body material that has a 4471 ± 6 Ma U‐Pb age, the same as that of Chelyabinsk (4452 ± 21 Ma). The distribution of the four known pre‐impact LL chondrite orbits is best matched by dynamical modeling if the source of LL chondrites is in the inner asteroid belt in a low inclined orbit, with the highly inclined Dishchii'bikoh being the result of interactions with Earth before impacting. [ABSTRACT FROM AUTHOR]

Aims: To investigate clinical characteristics and surgery outcomes of young children with focal cortical dysplasia (FCD) type II. Methods: Young children (onset age ≤6 years) with FCDII who underwent epileptic surgery in Children Epilepsy Center of Peking University First Hospital in 2014‐2018 were followed up for at least 6 months after surgery. Results: One hundred and twelve children with FCDII were included, with median age of onset 0.9 years (0.01‐5.9), who underwent surgery at 4.1 years old (0.8‐16.2). Focal seizures were most frequent (90.2%) and epileptic spasms presented in 23 (20.5%) cases. Epileptic encephalopathy was not uncommon (12.5%), associated with earlier epilepsy onset and higher rate of bilateral onset on ictal EEG (OR = 0.213, 9.059; P =.041,.004). At the last follow‐up, 88.4% achieved seizure‐free. Before surgery, 49.1% showed moderate/severe developmental delay, associated with earlier seizure onset and higher rate of history of epileptic encephalopathy (OR = 0.740, 5.160, P =.023,.042). For 48 children with preoperatively moderate/severe developmental delay, DQ rank at 6 months postsurgery was improved in only four cases. Conclusion: For young children with FCDII, they tend to present with epileptic encephalopathies and show moderate/severe developmental delay before surgery. The seizure outcome was favorable after surgery. For children with preoperatively moderate/severe developmental delay, developmental outcome at 6 months after surgery was not satisfactory. [ABSTRACT FROM AUTHOR]

Fluorinated ketones are widely prevalent in numerous biologically interesting molecules, and the development of novel transformations to access these structures is an important task in organic synthesis. Herein, we report the multicomponent radical acylfluoroalkylation of a variety of olefins in the presence of various commercially available aromatic aldehydes and fluoroalkyl reagents through N‐heterocyclic carbene organocatalysis. With this protocol, over 120 examples of functionalized ketones with diverse fluorine substituents have been synthesized in up to 99 % yield with complete regioselectivity. The generality of this catalytic strategy was further highlighted by its successful application in the late‐stage functionalization of pharmaceutical skeletons. Excellent diastereoselectivity could be achieved in the reactions forging multiple stereocenters. In addition, preliminary results have been achieved on the catalytic asymmetric variant of the olefin difunctionalization process. [ABSTRACT FROM AUTHOR]

A carbonaceous chondrite was recovered immediately after the fall near the village of Diepenveen in the Netherlands on October 27, 1873, but came to light only in 2012. Analysis of sodium and poly‐aromatic hydrocarbon content suggests little contamination from handling. Diepenveen is a regolith breccia with an overall petrology consistent with a CM classification. Unlike most other CM chondrites, the bulk oxygen isotopes are extremely 16O rich, apparently dominated by the signature of anhydrous minerals, distributed on a steep slope pointing to the domain of intrinsic CM water. A small subset plots closer to the normal CM regime, on a parallel line 2 ‰ lower in δ17O. Different lithologies in Diepenveen experienced varying levels of aqueous alteration processing, being less aqueously altered at places rather than more heated. The presence of an agglutinate grain and the properties of methanol‐soluble organic compounds point to active impact processing of some of the clasts. Diepenveen belongs to a CM clan with ~5 Ma CRE age, longer than most other CM chondrites, and has a relatively young K‐Ar resetting age of ~1.5 Ga. As a CM chondrite, Diepenveen may be representative of samples soon to be returned from the surface of asteroid (162173) Ryugu by the Hayabusa2 spacecraft. [ABSTRACT FROM AUTHOR]

We evaluated global soil organic carbon (SOC) stocks and turnover time predictions from a global land model (ELMv1-ECA) integrated in an Earth System Model (E3SM) by comparing them with observed soil bulk and Δ14C values around the world. We analyzed observed and simulated SOC stocks and Δ14C values using machine learning methods at the Earth System Model grid cell scale (~200 km). In grid cells with sufficient observations, the model provided reasonable estimates of soil carbon stocks across soil depth and Δ14C values near the surface but underestimated Δ14C at depth. Among many explanatory variables, soil albedo index, soil order, plant function type, air temperature, and SOC content were major factors affecting predicted SOC Δ14C values. The influences of soil albedo index, soil order, and air temperature were primarily important in the shallow subsurface (≤30 cm). We also performed sensitivity studies using different vertical root distributions and decomposition turnover times and compared to observed SOC stock and Δ14C profiles. The analyses support the role of vegetation in affecting soil carbon turnover, particularly in deep soil, possibly through supplying fresh carbon and degrading physical-chemical protection of SOC via root activities. Allowing for grid cell-specific rooting and decomposition rates substantially reduced discrepancies between observed and predicted Δ14C values and SOC content. Our results highlight the need for more explicit representation of roots, microbes, and soil physical protection in land models. [ABSTRACT FROM AUTHOR]

The Sariçiçek howardite meteorite shower consisting of 343 documented stones occurred on September 2, 2015 in Turkey and is the first documented howardite fall. Cosmogenic isotopes show that Sariçiçek experienced a complex cosmic‐ray exposure history, exposed during ~12–14 Ma in a regolith near the surface of a parent asteroid, and that an ~1 m sized meteoroid was launched by an impact 22 ± 2 Ma ago to Earth (as did one‐third of all HED meteorites). SIMS dating of zircon and baddeleyite yielded 4550.4 ± 2.5 Ma and 4553 ± 8.8 Ma crystallization ages for the basaltic magma clasts. The apatite U‐Pb age of 4525 ± 17 Ma, K‐Ar age of ~3.9 Ga, and the U,Th‐He ages of 1.8 ± 0.7 and 2.6 ± 0.3 Ga are interpreted to represent thermal metamorphic and impact‐related resetting ages, respectively. Petrographic; geochemical; and O‐, Cr‐, and Ti‐isotopic studies confirm that Sariçiçek belongs to the normal clan of HED meteorites. Petrographic observations and analysis of organic material indicate a small portion of carbonaceous chondrite material in the Sariçiçek regolith and organic contamination of the meteorite after a few days on soil. Video observations of the fall show an atmospheric entry at 17.3 ± 0.8 km s−1 from NW; fragmentations at 37, 33, 31, and 27 km altitude; and provide a pre‐atmospheric orbit that is the first dynamical link between the normal HED meteorite clan and the inner Main Belt. Spectral data indicate the similarity of Sariçiçek with the Vesta asteroid family (V‐class) spectra, a group of asteroids stretching to delivery resonances, which includes (4) Vesta. Dynamical modeling of meteoroid delivery to Earth shows that the complete disruption of a ~1 km sized Vesta family asteroid or a ~10 km sized impact crater on Vesta is required to provide sufficient meteoroids ≤4 m in size to account for the influx of meteorites from this HED clan. The 16.7 km diameter Antionia impact crater on Vesta was formed on terrain of the same age as given by the 4He retention age of Sariçiçek. Lunar scaling for crater production to crater counts of its ejecta blanket show it was formed ~22 Ma ago. [ABSTRACT FROM AUTHOR]

It has been proposed that all L chondrites resulted from an ongoing collisional cascade of fragments that originated from the formation of the ~500 Ma old asteroid family Gefion, located near the 5:2 mean‐motion resonance with Jupiter in the middle Main Belt. If so, L chondrite pre‐atmospheric orbits should be distributed as expected for that source region. Here, we present contradictory results from the orbit and collisional history of the October 24, 2015, L6 ordinary chondrite fall at Creston, CA (here reclassified to L5/6). Creston's short 1.30 ± 0.02 AU semimajor axis orbit would imply a long dynamical evolution if it originated from the middle Main Belt. Indeed, Creston has a high cosmic ray exposure age of 40–50 Ma. However, Creston's small meteoroid size and low 4.23 ± 0.07° inclination indicate a short dynamical lifetime against collisions. This suggests, instead, that Creston originated most likely in the inner asteroid belt and was delivered via the ν6 resonance. The U‐Pb systematics of Creston apatite reveals a Pb‐Pb age of 4,497.1 ± 3.7 Ma, and an upper intercept U‐Pb age of 4,496.7 ± 5.8 Ma (2σ), circa 70 Ma after formation of CAI, as found for other L chondrites. The K‐Ar (age ~4.3 Ga) and U,Th‐He (age ~1 Ga) chronometers were not reset at ~500 Ma, while the lower intercept U‐Pb age is poorly defined as 770 ± 320 Ma. So far, the three known L chondrites that impacted on orbits with semimajor axes a <2.0 AU all have high (>3 Ga) K‐Ar ages. This argues for a source of some of our L chondrites in the inner Main Belt. Not all L chondrites originate in a continuous population of Gefion family debris stretching across the 3:1 mean‐motion resonance. [ABSTRACT FROM AUTHOR]

An efficient diastereo‐ and enantioselective formal oxo‐Diels‐Alder reaction of enolizable aliphatic aldehydes and 5‐alkenyl thiazolones was developed through chiral amine catalysis. With a robust enamine activation strategy, both simple aliphatic aldehydes and a challenging aqueous acetaldehyde could participate well as competent dienophiles in the reaction. A variety of thiazole‐fused dihydropyran derivatives were facilely produced in up to 99% yield with up to >99:1 e.r. under mild conditions. Interestingly, a high dosage of the inexpensive aqueous acetaldehyde in a similar catalytic system could lead to a densely functionalized thiazolone product through a three‐component cascade reaction, suggesting a step‐wise mechanism for the established [4+2] annulation process. [ABSTRACT FROM AUTHOR]

Catalyst and solvent‐free reactions have attracted great attention from chemists because of their inherent advantages that coincide with the principles of sustainable chemistry and the increasing public awareness of environmental protection. Here, we disclose the first catalyst‐free intermolecular cyclopropanation of phenyliodonium ylides with electron‐deficient alkenes. Full conversion can be achieved at ambient temperature, in the absence of any catalyst, within a short reaction time. Importantly, such reactions work reasonably well in water or even under solvent‐free conditions, which enables a green, convenient and efficient way to synthesize valuable multifunctional vinylcyclopropanes. Clean and efficient! A catalyst‐free intermolecular cyclopropanation between phenyliodonium ylides and electron‐deficient olefins has been developed, which could be completed generally within 5 minutes without the use of any metal or organic catalyst. In addition, this reaction works quite well in water or even under solvent‐free conditions, which enables a green, convenient and efficient way to synthesize a range of valuable vinylcyclopropanes with different substituents and functionalities. [ABSTRACT FROM AUTHOR]

Abstract: Magnesium isotopic compositions of evaporite deposits may record information concerning brine evolution during deposition. We report Mg isotopic values (δ26MgDSM3) measured from an evaporite deposit of langbeinite (K2Mg2(SO4)3) found in the Permian Salado Formation. We used these data to model Mg isotope fractionation between langbeinite and its parent brine. In addition, both measured and theoretical results are used to estimate precipitation temperature and interpret depositional environment. The Salado langbeinite δ26Mg values are relatively low and fall within a relatively narrow range (–4.12 ± 0.03‰ to −3.81 ± 0.07‰). Equilibrium fractionation factors between langbeinite and aqueous Mg2+ solutions were calculated using quantum chemical density functional theory. All computations were performed at the B3LYP/6‐31 + G(d,p) level. Solvation effects were addressed using a solvent model (“water‐droplet” approach) and mineral structures were investigated using volume variable cluster models (VVCM). The equilibrium Mg isotopic fractionation factors α between langbeinite and model brine solution we obtained are 1.0005, 1.0004, and 1.0003 (Δ26Mglangb‐water≈103lnα = 0.473‰, 0.390‰, and 0.322‰) at 10°C, 25°C, and 40°C, respectively. These relatively large equilibrium fractionation factors indicate significant Mg isotope fractionation between langbeinite and its parent brine during precipitation, as langbeinite preferentially incorporates the heavier 26Mg and 25Mg isotopes. Rayleigh distillation modeling of the Salado langbeinite's relatively light Mg isotopic composition requires δ26MgDSM3 values of −4‰ for the parent brine. Models favor a precipitation temperature as high as 40°C under equilibrium conditions. Potential disequilibrium precipitation conditions suggested by Mg isotopic data also imply rapid deposition in a hot, arid sedimentary environment prevailing in the southwestern U.S. during the Late Permian. [ABSTRACT FROM AUTHOR]

Abstract: The 187Re‐187Os isotopic systematics of many bulk chondrites plot well beyond analytical uncertainties of a primordial isochron. Limited variations in 187Os/188Os, coupled with large variations in Re/Os ratios among chondrites, suggest that this apparently open‐system behavior is a result of the comparatively recent gain or loss of Re and/or Os. In order to assess whether or not rapid alteration in the terrestrial environment could be responsible for open‐system behavior in chondrites, four pieces of the Sutter's Mill meteorite were examined for Os isotopic systematics and abundances of highly siderophile elements. Pieces SM1 and SM2 were collected prior to a rain event, within 2 days of the fall. Pieces SM51 and SM53 were collected after a rain event. There are significant but minor relative and absolute variations in the abundances of the highly siderophile elements, as well as 187Os/188Os among the four pieces. Rhenium‐Os isotopic data for SM1 and SM2 plot within analytical uncertainties of a primordial isochron, while powders made from SM51 and SM53 do not. These results suggest that interactions with rain caused some redistribution of Re, and to a lesser extent Os, within small pieces of the meteorite. Thus, Re‐Os isotopic systematics of

Summary: Complex coacervation of gelatin (GE) with carboxymethylcellulose (CMC) and the microencapsulation of shiitake essential oil (SEO) using the GE‐CMC coacervate were investigated. The ζ‐potential and coacervate yield data showed that the optimal complexation pH and CMC/GE ratio were 4.0 and 0.15 g g−1, respectively. At this condition, the coacervate yield was 85.35 ± 4.89% and ζ‐potential was almost zero. The SEO contained microcapsules fabricated by the GE‐CMC coacervate were also electrostatic inducted formation, and the highest encapsulation efficiency was shown to be 85.75 ± 2.89%. The rheological measurement indicated that the GE‐CMC coacervated microcapsules had a viscoelastic solid behaviour (G’ > G”) which was resulted mainly from the interactions between GE molecules and CMC chains. The improved oxidative stability and odour attenuation effect of the GE‐CMC coacervated microcapsules were believed to be attributed to the increased protection against oxidation and flavour release by providing a physical barrier after complex coacervation. [ABSTRACT FROM AUTHOR]

Nitrogen‐containing bisphosphonates (N‐BPs) have been used widely to treat various bone diseases by inhibiting the key enzyme farnesyl pyrophosphate synthase (FPPS) in the mevalonate pathway. Understanding the structure–activity relationships and the action mechanisms of these bisphosphonates is instructive for the design and the development of novel potent inhibitors. Here, a series of N‐BPs inhibitors of human FPPS (hFPPS) were investigated using a combination of three‐dimensional quantitative structure–activity relationship (3D‐QSAR), molecular docking, and three‐layer ONIOM studies. The constructed 3D‐QSAR model yielded a good correlation between the predicted and experimental activities. Based on the analysis of comparative molecular field analysis (CoMFA) contour maps, a series of novel N‐BPs inhibitors were designed and ten novel potent N‐BPs inhibitor candidates were screened out. Molecular docking and ONIOM (B3LYP/6‐31 + G*:PM6:Amber) calculations revealed that the inhibitors bound to the active site of hFPPS via hydrogen‐bonding interactions, hydrophobic interactions, and cation‐π interactions. Six novel N‐BPs inhibitors with better biological activities and higher lipophilicity were further screened out from ten candidates based on the calculated interaction energy. This study will facilitate the discovery of novel N‐BPs inhibitors with higher activity and selectivity. [ABSTRACT FROM AUTHOR]

Abstract: The Antarctic achondrite Graves Nunataks 06128 (GRA 06128) and Graves Nunataks 06129 (GRA 06129) represent a unique high‐temperature, nonbasaltic magmatism in the early solar system. These objects have been interpreted as products of low‐degree partial melting of volatile‐rich chondritic material, which may have been the asteroid parent bodies of brachinite. Previous studies have investigated their crystallization and metamorphic history with various isotope systematics. Here, we report the U‐Pb intercept age of 4466 ± 29 Ma and the weighted‐average 207Pb‐206Pb age of 4460 ± 30 Ma for the Cl‐apatite grains from GRA 06129. Our apatite ages are obviously younger than that of the 26Al‐26Mg model age (4565.9 ± 0.3 Ma; Shearer et al. ), but are the same as the 40Ar‐39Ar age obtained via step‐heating of the bulk rock (4460 ± 28 Ma; Fernandes and Shearer ; Shearer et al. ). Based on petrographic observations, merrillites are usually rimmed by apatite and exist as inclusions in apatite. Therefore, the apatite U‐Pb age from GRA 06129 probably records a metamorphic event of replacing merrillite with apatite, caused by Cl‐rich melts or fluids on their parent body. A collisional event has provided the impact heating for this metamorphic event. Increasing amounts of geochronologic evidence show that the giant impact of the Moon‐forming event has affected the asteroid belt at 4450–4470 Ma (Bogard and Garrison ; Popova et al. ; Yin et al. ; Zhang et al. ). Considering the contemporary metamorphic events for GRA 06129 (4460 ± 30 Ma), it is likely that the asteroid parent body of GRA 06129 was also affected by the same giant impact as the Moon‐forming event. [ABSTRACT FROM AUTHOR]

Abstract: Asymmetric construction of halogenated quaternary carbon centers under mild reaction conditions remains challenging. Reported here is an unprecedented and highly stereoselective Brønsted base catalyzed [4+2] cycloaddition between either α‐chloro‐ or α‐bromoaldehydes and cyclic enones. The key intermediate, an α‐halogenated enolate, is susceptible to dehalogenation and can be stabilized and stereochemically controlled using bifunctional tertiary amines. This method provides facile access to a collection of optically pure bicyclic dihydropyrans having three contiguous stereocenters, including a halogen‐bearing quaternary carbon center. Of note, the product can be transformed in situ into densely functionalized spirocyclopropanes in a highly efficient and stereoselective manner. [ABSTRACT FROM AUTHOR]

Abstract: Here we report a secondary amine‐catalyzed, highly enantioselective [3+3] cyclization reaction of α‐alkylidene pyrazolinones and α,β‐unsaturated aldehydes, which facilely delivers a variety of enantioenriched spiropyrazolones showing structural and stereochemical complexity. The reaction uses an iminium ion activation strategy to activate both the β‐ and ipso‐positions of the enals as dielectrophilic sites. A broad range of substrates are compatible with this mild reaction system. [ABSTRACT FROM AUTHOR]

Keywords: acylation; hydrogen atom transfer; inert C-H bonds; NHC catalysis; radical reactions EN acylation hydrogen atom transfer inert C-H bonds NHC catalysis radical reactions 1 1 1 02/22/23 20230220 NES 230220 B The Front Cover b illustrates the great synthetic potential of I N i -heterocyclic carbene (NHC) organocatalysis when it is combined with the hydrogen atom transfer (HAT) strategy. With this synthetic protocol, chemists could realize organocatalytic functionalizations of various C-H bonds to prepare value-added molecules, extending the substrate scope of NHC catalysis to include abundant, simple feedstock materials. Acylation, hydrogen atom transfer, inert C-H bonds, NHC catalysis, radical reactions. [Extracted from the article]

Groundwater quality is a concern in alluvial aquifers that underlie agricultural areas, such as in the San Joaquin Valley of California. Shallow domestic wells (less than 150 m deep) in agricultural areas are often contaminated by nitrate. Agricultural and rural nitrate sources include dairy manure, synthetic fertilizers, and septic waste. Knowledge of the relative proportion that each of these sources contributes to nitrate concentration in individual wells can aid future regulatory and land management decisions. We show that nitrogen and oxygen isotopes of nitrate, boron isotopes, and iodine concentrations are a useful, novel combination of groundwater tracers to differentiate between manure, fertilizers, septic waste, and natural sources of nitrate. Furthermore, in this work, we develop a new Bayesian mixing model in which these isotopic and elemental tracers were used to estimate the probability distribution of the fractional contributions of manure, fertilizers, septic waste, and natural sources to the nitrate concentration found in an individual well. The approach was applied to 56 nitrate-impacted private domestic wells located in the San Joaquin Valley. Model analysis found that some domestic wells were clearly dominated by the manure source and suggests evidence for majority contributions from either the septic or fertilizer source for other wells. But, predictions of fractional contributions for septic and fertilizer sources were often of similar magnitude, perhaps because modeled uncertainty about the fraction of each was large. For validation of the Bayesian model, fractional estimates were compared to surrounding land use and estimated source contributions were broadly consistent with nearby land use types. [ABSTRACT FROM AUTHOR]

Meteorites have been found on the small Misfits Flat dry lakebed near Stagecoach, Nevada (119.382W, +39.348N). Since the first find on Sept. 22, 2013, a total of 58 stones of weathering stage W2/3 with a combined mass of 339 g have been collected in 19 visits to the area. This small (3.3 x 3.6 km) lakebed is now a newly designated dense collection area (DCA). Most meteorites were found in a small 350 x 180 m area along the north shore and most are fragments of several broken individual stones. Three of these fragments were classified as an LL4/5 of shock stage S2, now named Misfits Flat 001, one of which (stone MF33) fell 8.1 ± 1.3 ka ago based on the 14C terrestrial age, assuming it came from a 20-80 cm diameter meteoroid. In addition, a small darkly crusted meteorite MF34, now named Misfits Flat 002, was found 820 m WSW from the main mass. This meteorite is classified as an LL5 ordinary chondrite with shock stage S4/5. The meteorite is saturated in 14C at 63 dpm kg-1, suggesting it originated from the center of a 0.5 m diameter meteoroid, or deep inside a ~1.0 m meteoroid, less than 300 yr ago. Accounts exist of a fireball seen at 13:15 UT on March 2, 1895, that are consistent with the find location of Misfits Flat 002. [ABSTRACT FROM AUTHOR]

Recent studies have shown that major meteorite groups possess their own characteristic 54Cr values, demonstrating the utility of Cr isotopes for identifying genetic relationships between the planetary materials in conjunction with other classical tools, such as oxygen isotopes. In this study, we performed Cr isotope analyses for whole rocks and chemically separated phases of the new CM2 chondrite, Sutter's Mill ( SM 43 and 51). The two whole rocks of Sutter's Mill show essentially identical ε54Cr excesses ( SM 43 = +0.95 ± 0.09ε, SM 51 = +0.88 ± 0.07ε), relative to the Earth. These values are the same within error with that of the CM2-type Murchison (+0.89 ± 0.08ε), suggesting that parent bodies of Sutter's Mill and Murchison were formed from the same precursor materials in the solar nebula. Large ε54Cr excess of up to 29.40ε is observed in the silicate phase of Sutter's Mill, while that of Murchison shows 15.74ε. Importantly, the leachate fractions of both Sutter's Mill and Murchison form a steep linear anticorrelation between ε54Cr and ε53Cr, cross-cutting the positive correlation previously observed in carbonaceous chondrites. The fact that L4 acid leachate fraction contains higher 54Cr excesses than that of L5 step designed to dissolve refractory minerals suggests that spinel is not a major 54Cr carrier. We also note that L5 contains 53Cr anomalies lower than the solar initial value, suggesting it carries a component of nucleosynthetic anomaly unrelated to the 53Mn decay. We have identified five endmember components of nucleosynthetic origin among the early solar system materials. [ABSTRACT FROM AUTHOR]

Based upon our characterization of three separate stones by electron and X-ray beam analyses, computed X-ray microtomography, Raman microspectrometry, and visible- IR spectrometry, Sutter's Mill is a unique regolith breccia consisting mainly of various CM lithologies. Most samples resemble existing available CM2 chondrites, consisting of chondrules and calcium-aluminum-rich inclusion (CAI) set within phyllosilicate-dominated matrix (mainly serpentine), pyrrhotite, pentlandite, tochilinite, and variable amounts of Ca-Mg-Fe carbonates. Some lithologies have witnessed sufficient thermal metamorphism to transform phyllosilicates into fine-grained olivine, tochilinite into troilite, and destroy carbonates. One finely comminuted lithology contains xenolithic materials (enstatite, Fe-Cr phosphides) suggesting impact of a reduced asteroid (E or M class) onto the main Sutter's Mill parent asteroid, which was probably a C class asteroid. One can use Sutter's Mill to help predict what will be found on the surfaces of C class asteroids such as Ceres and the target asteroids of the OSIRIS- REx and Hayabusa 2 sample return missions (which will visit predominantly primitive asteroids). C class asteroid regolith may well contain a mixture of hydrated and thermally dehydrated indigenous materials as well as a significant admixture of exogenous material would be essential to the successful interpretation of mineralogical and bulk compositional data. [ABSTRACT FROM AUTHOR]

We determined the abundances and enantiomeric compositions of amino acids in Sutter's Mill fragment #2 (designated SM2) recovered prior to heavy rains that fell April 25-26, 2012, and two other meteorite fragments, SM12 and SM51, that were recovered postrain. We also determined the abundance, enantiomeric, and isotopic compositions of amino acids in soil from the recovery site of fragment SM51. The three meteorite stones experienced terrestrial amino acid contamination, as evidenced by the low d/l ratios of several proteinogenic amino acids. The d/l ratios were higher in SM2 than in SM12 and SM51, consistent with rain introducing additional l-amino acid contaminants to SM12 and SM51. Higher percentages of glycine, β-alanine, and γ-amino- n-butyric acid were observed in free form in SM2 and SM51 compared with the soil, suggesting that these free amino acids may be indigenous. Trace levels of d+ l-β-aminoisobutyric acid (β- AIB) observed in all three meteorites are not easily explained as terrestrial contamination, as β- AIB is rare on Earth and was not detected in the soil. Bulk carbon and nitrogen and isotopic ratios of the SM samples and the soil also indicate terrestrial contamination, as does compound-specific isotopic analysis of the amino acids in the soil. The amino acid abundances in SM2, the most pristine SM meteorite analyzed here, are approximately 20-fold lower than in the Murchison CM2 carbonaceous chondrite. This may be due to thermal metamorphism in the Sutter's Mill parent body at temperatures greater than observed for other aqueously altered CM2 meteorites. [ABSTRACT FROM AUTHOR]

Radiometric dating of secondary minerals can be used to constrain the timing of aqueous alteration on meteoritic parent bodies. Dolomite is a well-documented secondary mineral in CM chondrites, and is thought to have formed by precipitation from an aqueous fluid on the CM parent body within several million years of accretion. The petrographic context of crosscutting dolomite veins indicates that aqueous alteration occurred in situ, rather than in the nebular setting. Here, we present 53Mn-53Cr systematics for dolomite grains in Sutter's Mill section SM51-1. The Mn-Cr isotope data show well-resolved excesses of 53Cr correlated with 55Mn/52Cr ratio, which we interpret as evidence for the in situ decay of radioactive 53Mn. After correcting for the relative sensitivities of Mn and Cr using a synthetic Mn- and Cr-bearing calcite standard, the data yield an isochron with slope corresponding to an initial 53Mn/55Mn ratio of 3.42 ± 0.86 × 10−6. The reported error includes systematic uncertainty from the relative sensitivity factor. When calculated relative to the U-corrected Pb-Pb absolute age of the D'Orbigny angrite, Sutter's Mill dolomites give a formation age between 4564.8 and 4562.2 Ma (2.4-5.0 Myr after the birth of the solar system). This age is contemporaneous with previously reported ages for secondary carbonates in CM and CI chondrites. Consistent carbonate precipitation ages between the carbonaceous chondrite groups suggest that aqueous alteration was a common process during the early stages of parent body formation, probably occurring via heating from internal 26Al decay. The high-precision isochron for Sutter's Mill dolomite indicates that late-stage processing did not reach temperatures that were high enough to further disturb the Mn-Cr isochron. [ABSTRACT FROM AUTHOR]