Hydroxy-2-oxindole derivatives, which contain a quaternary stereogenic center at the 3-position, are a family of structurally diverse natural or nonnatural products with interesting biological activities. [1] The asymmetric synthesis of 3-hydroxy-2-oxindole derivatives, such as donaxaridine (1), [1b-c] (R)chimonamidine (2), [1d] CPC-1 (3), [1e] and (À)-flustraminol B (4) [1f] (Scheme 1, series I), has recently been intensely pursued, as these compounds exhibit a broad spectrum of biological activities and are promising potential drugs. Previously established methods [2] for the preparation of these derivatives mainly focused on the asymmetric hydroxylation of 3-substituted 2-oxindoles [3] and the nucleophilic addition to isatins, [4] employing compound A as a viable synthon (Scheme 1). The synthesis of related 3-hydroxy-2oxindole derivatives (5-7) of series II has attracted considerable interest for a long time because of their fascinating architectures and potential biological activities. For example, spirolactone 5 has shown potential cytotoxic activity. [1g-i] Spiroether 6 was reported to be a CB2 agonist and is thus a potential drug candidate for reducing neuropathic and bone pains, and for treating a host of diseases, including osteoarthritis, atherosclerosis, osteoporosis, and cancers. [1g] Hexahydrozaepino[2,3-b]indole 7, which bears a unique 5,7bicyclic framework, can be used as a tranquilizer for mammals and birds. [1h-i] However, to the best of our knowledge, no asymmetric protocol that affords this class of compounds has been presented to date.Compared with the traditional "single target" approach, the design of a common intermediate is the key in the total synthesis of different products through a divergent synthesis strategy, which has enabled the formation of a variety of target molecules without compromising efficiency. [5] As part of our ongoing research efforts toward the development and utilization of synthetic tools for the formation of quaternary stereogenic centers, [3b, 6] we were interested in designing a novel organocatalytic asymmetric reaction to achieve the divergent synthesis of 3-hydroxy-2-oxindole derivatives, including those in series I and II.Retrosynthetic analyses suggested that the synthetic route to intermediates A and B was reasonable. We deduced that compound C could be assembled as the common intermediate for the divergent synthesis of 3-hydroxy-2-oxindole derivatives of series I and II. We therefore focused on the asymmetric vinylogous aldol reaction of the carbonyl-activated allyl nucleophile D with isatin (Scheme 1).The Mukaiyama-type aldol reaction of silyl dienol ethers is the favored protocol to furnish vinylogous aldol adducts, but can suffer from low atom economy and efficiency. [7] In this context, a direct asymmetric approach for these reactions would be highly valuable. In recent years, cyclic 2-furanone derivatives have been used as versatile nucleophiles in direct vinylogous aldol reactions, as shown by the research groups of Zhang, [8a] Terada, [8b...

Objective The purpose of this study is to compare the dosimetric distribution of ipsilateral proton beam radiation therapy (PBRT) to intensity-modulated radiation therapy (IMRT) in the tooth-bearing region of the mandible in patients with head and neck cancer (HNC). Patients and Methods The mandibular dosimetric distribution of HNC patients treated with ≥60 Gy relative biological equivalent (RBE) PBRT were evaluated. The mean radiation doses were calculated in five regions: Ipsilateral molar, ipsilateral premolar, anterior, contralateral premolar and contralateral molar (CM). The CM was used as reference region for comparative analysis. The mandibular dosimetric distribution of patients treated with PBRT was compared to IMRT patients with similar tumor sites and planning target volumes. Results The mean radiation dose to the contralateral regions was lower in patients treated with PBRT compared to IMRT. The average mean radiation dose to the reference region (CM) in patients treated with PBRT (RBE) vs. IMRT: oropharynx [2.2 Gy vs. 23.2 Gy, P <0.00002], parotid [0 Gy vs. 11.8 Gy, P = 0.01] and oral cavity [0.4 Gy vs. 15.6 Gy, P = 0.006]. Conclusion This study demonstrates the effective tissue-sparing capability of PBRT compared to IMRT. Utilization of PBRT could translate to less radiation-related toxicity.

A surface plasmon-enhanced resonance light scattering method has been developed. The method features strong light scattering but very weak background, and after incorporating with selective sample extraction and ion-association complexation using rhodamine B and KI as reactants, it could selectively determine Cr(VI) in both of standard and real samples, reaching a limit of detection down to 20 nM which is about 40-fold as sensitive as flame atomic absorption spectrometry and 140-fold as sensitive as fluorescent spectroscopy. Its linear working range was found in between 40 and 320 nM, with a relative standard deviation of peak height at <3% (n = 5) and recovery between 94.8-104.9%. In theory, the method is applicable to the analysis of all substances able to produce or destroy I2.

Purpose To demonstrate temporal lobe necrosis (TLN) rate and clinical/dose-volume factors associated with TLN in radiation-naïve patients with head and neck cancer treated with proton therapy where the field of radiation involved the skull base. Materials and Methods Medical records and dosimetric data for radiation-naïve patients with head and neck cancer receiving proton therapy to the skull base were retrospectively reviewed. Patients with &lt;3 months of follow-up, receiving &lt;45 GyRBE or nonconventional fractionation, and/or no follow-up magnetic resonance imaging (MRI) were excluded. TLN was determined using MRI and graded using Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Clinical (gender, age, comorbidities, concurrent chemotherapy, smoking, radiation techniques) and dose-volume parameters were analyzed for TLN correlation. The receiver operating characteristic curve and area under the curve (AUC) were performed to determine the cutoff points of significant dose-volume parameters. Results Between 2013 and 2019, 234 patients were included. The median follow-up time was 22.5 months (range = 3.2–69.3). Overall TLN rates of any grade, ≥ grade 2, and ≥ grade 3 were 5.6% (N = 13), 2.1%, and 0.9%, respectively. The estimated 2-year TLN rate was 4.6%, and the 2-year rate of any brain necrosis was 6.8%. The median time to TLN was 20.9 months from proton completion. Absolute volume receiving 40, 50, 60, and 70 GyRBE (absolute volume [aV]); mean and maximum dose received by the temporal lobe; and dose to the 0.5, 1, and 2 cm3 volume receiving the maximum dose (D0.5cm3, D1cm3, and D2cm3, respectively) of the temporal lobe were associated with greater TLN risk while clinical parameters showed no correlation. Among volume parameters, aV50 gave maximum AUC (0.921), and D2cm3 gave the highest AUC (0.935) among dose parameters. The 11-cm3 cutoff value for aV50 and 62 GyRBE for D2cm3 showed maximum specificity and sensitivity. Conclusion The estimated 2-year TLN rate was 4.6% with a low rate of toxicities ≥grade 3; aV50 ≤11 cm3, D2cm3 ≤62 GyRBE and other cutoff values are suggested as constraints in proton therapy planning to minimize the risk of any grade TLN. Patients whose temporal lobe(s) unavoidably receive higher doses than these thresholds should be carefully followed with MRI after proton therapy.

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A Lewis base catalyzed allylic hydroxylation of Morita-Baylis-Hillman (MBH) carbonates has been developed. Various chiral MBH alcohols can be synthesized in high yields (up to 99%) and excellent enantioselectivities (up to 94% ee). This is the first report using water as a nucleophile in asymmetric organocatalysis. The nucleophilic role of water has been verified using (18)O-labeling experiments.

The Fenhe River basin is the main agricultural and industrial developed area in Shanxi province, China.

The radial velocity (RV) is a basic physical quantity which can be determined through Doppler shift of the spectrum of a star. The precision of RV measurement depends on the resolution of the spectrum we used and the accuracy of wavelength calibration. In this work, radial velocities of LAMOST-II medium resolution (R ∼ 7500) spectra are measured for 1,594,956 spectra (each spectrum has two wavebands) through matching with templates. A set of RV standard stars are used to recalibrate the zero point of the measurement, and some reference sets with RVs derived from medium/high-resolution observations are used to evaluate the accuracy of the measurement. Comparing with reference sets, the accuracy of our measurement can get 0.0227 km s −1 with respect to radial velocities standard stars. The intrinsic precision is estimated with the multiple observations of single stars, which can achieve to 1.36 km s −1 ,1.08 km s −1 , 0.91 km s −1 for the spectra at signal-to-noise levels of 10, 20, 50, respectively. These big samples of RVs were obtained through spectra with different resolving power, which provides astronomers useful tools for dissecting and understanding the structure of the Milky Way. A large sample with consistent measured RVs is a key underpinning for a lot of research work, for example, Geller et al. (2015) use RVs to determine membership of a stellar cluster. Besides, researchers analyzed the RV variations to constrain the stellar pulsation model (Britavskiy et al. 2018) and to determinate the properties of the eclipsing binary stars (He lminiak et al. 2018; Martin et al. 2019).