The first data release(DR1) of the LAMOST regular survey

The Large sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs. Objects in both the pilot survey and the first year regular survey are included in the LAMOST DR1. The pilot survey started in October 2011 and ended in June 2012, and the data have been released to the public as the LAMOST Pilot Data Release in August 2012. The regular survey started in September 2012, and completed its first year of operation in June 2013. The LAMOST DR1 includes a total of 1202 plates containing 2 955 336 spectra, of which 1 790 879 spectra have observed signalto-noise ratio（SNR） ≥ 10. All data with SNR ≥ 2 are formally released as LAMOST DR1 under the LAMOST data policy. This data release contains a total of 2 204 696 spectra, of which 1 944 329 are stellar spectra, 12 082 are galaxy spectra and 5017 are quasars. The DR1 not only includes spectra, but also three stellar catalogs with measured parameters： late A,FGK-type stars with high quality spectra（1 061 918 entries）, A-type stars（100 073 entries）, and M-type stars（121 522 entries）. This paper introduces the survey design, the observational and instrumental limitations, data reduction and analysis, and some caveats. A description of the FITS structure of spectral files and parameter catalogs is also provided.

Data release of the LAMOST pilot survey

This paper describes the data release of the LAMOST pilot survey, which includes data reduction, calibration, spectral analysis, data products and data access. The accuracy of the released data and the information about the FITS headers of spectra are also introduced. The released data set includes 319 000 spectra and a catalog of these objects.

A catalog of early-type emission-line stars and Hα line profiles from LAMOST DR2

We present a catalog including 11 204 spectra of 10436 early-type emission-line stars from LAMOST DR2, among which 9752 early-type emission-line spectra are newly discovered. For these early- type emissionqine stars, we discuss the morphological and physical properties of their low-resolution spectra. In this spectral sample, the Hα emission profiles display a wide variety of shapes. Based on the Hα line profiles, these spectra are categorized into five distinct classes： single-peak emission, single-peak emission in absorption, double-peak emission, double-peak emission in absorption, and P-Cygni profiles. To better understand what causes the Hc~ line profiles, we divide these objects into four types from the perspective of physical classification, which include classical Be stars, Herbig Ae/Be stars, close binaries and spectra contaminated by H n regions. The majority of Herbig Ae/Be stars and classical Be stars are identified and separated using a （H-K, K-W1） color-color diagram. We also discuss 31 binary systems that are listed in the SIMBAD on-line catalog and identify 3600 spectra contaminated by HⅡ regions after cross-matching with positions in the Dubout-Crillon catalog. A statistical analysis of line profiles versus classifications is then conducted in order to understand the distribution of Hc~ profiles for each type in our sample. Finally, we also provide a table of 172 spectra with Fen emission lines and roughly calculate stellar wind velocities for seven spectra with P-Cygni profiles.

Radial velocity measurements from LAMOST medium-resolution spectroscopic observations: a pointing towards the Kepler field

Radial velocity is one of the key measurements in understanding the fundamental properties of stars, stellar clusters and the Galaxy. A plate of stars in the Kepler field was observed in May of 2018 with the medium-resolution spectrographs of LAMOST, aiming to test the performance of this new system which is the upgraded equipment of LAMOST after the first five-year regular survey. We present our analysis on the radial velocity measurements(RVs) derived from these data. The results show that slight and significant systematic errors exist among the RVs obtained from the spectra collected by different spectrographs and exposures, respectively. After correcting the systematic errors with different techniques, the precision of RVs reaches ～1.3,～1.0,～0.5 and ～0.3 km s^(-1) at S/Nr = 10, 20, 50 and 100, respectively. Comparing with the RVs of standard stars from the APOGEE survey, our RVs are calibrated with a zero-point shift of～7 km s^(-1). The results indicate that the LAMOST medium-resolution spectroscopic system may provide RVs with a reasonable accuracy and precision for the selected targets.

LAMOST Time-Domain survey:first results of four K2 plates

From Oct.2019 to Apr.2020,LAMOST performed a time-domain(TD)spectroscopic survey of four K2 plates with both low-and medium-resolution observations.The low-resolution spectroscopic survey acquired 282 exposures(≈46.6 h)over 25 nights,yielding a total of about 767000 spectra,and the medium-resolution survey took 177 exposures(≈49.1 h)over 27 nights,collecting about 478000 spectra.More than 70%/50%of low-resolution/medium-resolution spectra have signal-to-noise ratio higher than 10.We determine stellar parameters(e.g.,Teff,log g,[Fe/H])and radial velocity(RV)with different methods,including LASP,DD-Payne and SLAM.In general,these parameter estimations from different methods show good agreement,and the stellar parameter values are consistent with those of APOGEE.We use the Gaia DR2 RV values to calculate a median RV zero point(RVZP)for each spectrograph exposure by exposure,and the RVZP-corrected RVs agree well with the APOGEE data.The stellar evolutionary and spectroscopic masses are estimated based on the stellar parameters,multi-band magnitudes,distances and extinction values.Finally,we construct a binary catalog including about 2700 candidates by analyzing their light curves,fitting the RV data,calculating the binarity parameters from medium-resolution spectra and cross-matching the spatially resolved binary catalog from Gaia EDR3.The LAMOST TD survey is expected to represent a breakthrough in various scientific topics,such as binary systems,stellar activity,stellar pulsation,etc.

Progress in Chemical Synthesis of Peptides and Proteins

For the proteins that cannot be expressed exactly by cell expression technology (e.g., proteins with multiple posttranslational modifications or toxic proteins), chemical synthesis is an important substitute. Given the limited peptide length offered by solid-phase peptide synthesis invented by Professor Merrifield, peptide ligation plays a key role in long peptide or protein synthesis by ligating two small peptides to a long one. Moreover, high-molecular-weight proteins must be synthesized using two or more peptide ligation steps, and sequential peptide ligation is such an efficient way. In this paper, we reviewed the development of chemical protein synthesis, including solid-phase peptide synthesis, chemical ligation, and sequential chemical ligation. © 2017, The Author(s).

Diffuse Interstellar Bandsλ6379,λ6614,andλ6660 in the LAMOST-MRS Spectra

Diffuse interstellar bands(DIBs)have always been a mysterious existence in astronomical research.In this work,we provide more DIB samples to slightly uncover this mystery.With the LAMOST medium-resolution survey(MRS)spectra,we detected three DIBsλ6379,λ6614,andλ6660,obviously superimposed on the spectra of11,003 stars.These spectra cover spectral types from O to K,which can provide a large number of candidates for further research on DIBs.The sample shows a clear positive correlation between the strength of DIBs and extinction,which agrees with the result in the literature.In addition,there exist two peaks in each of the velocity distribution of these three DIBs,and the velocity differences between two peaks of each pair are consistent.The reason for the two velocity components is due to the Galactic rotation.

Nearby M subdwarfs from LAMOST data release 2

We identify 108 M subdwarfs（sd Ms） out of more than two hundred thousand M type spectra from the second data release（DR2） of the LAMOST regular survey. This sample, among which 58 members are identified for the first time, includes 33 extreme subdwarfs（esd Ms） and 11 ultra subdwarfs（usd Ms）.The selection is based on the usual ratio of absorption depth of Ca H2, Ca H3 and TiO 5 band systems.We also emphasize the use of the Ca H1 band. We provide estimates of spectral subtype（SPT）, L′epine metallicity index ζ, effective temperature and [Fe/H]. Both ζ–[Fe/H] and SPT–Teff figures show reasonable consistency; compared to PHOENIX model spectra, average rounded values of [Fe/H] for sd Ms, esd Ms and usd Ms are respectively –0.5, –1 and –1.5. The photometric distances are estimated, indicating that most sources are located within 500 pc of the Sun and 350 pc of the Galactic disk. Velocities and 3D Galactic motions are also briefly discussed. Among the 108 subdwarfs, seven stars appear to be active with a significant Hα emission line. The source LAMOST J104521.52＋482823.3 is a white dwarf- M subdwarf binary, while LAMOST J123045.52＋410943.8, also active, exhibits carbon features in red.

A sample of E+A galaxy candidates in the Second Data Release of LAMOST Survey

A sample of 70 E＋A galaxies is selected from 37 206 galaxies in the second data release of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST）. This sample is selected according to the criteria for E＋A galaxies defined by Goto, and each of these objects is further visually identified. In this sample, most objects are low redshift E＋A galaxies with z 〈 0.25, and are located in an area of the sky with high Galactic latitude and magnitude from 14 to 18 mag in the g, r and i bands. A stellar population analysis of the whole sample indicates that the E＋A galaxies are characterized by both young and old stellar populations（SPs）, and the metalrich SPs have relatively higher contributions than the metal-poor ones. Additionally, a morphological classification of these objects is performed based on images taken from the Sloan Digital Sky Survey.

Overview of epigenetic degraders based on PROTAC, molecular glue, and hydrophobic tagging technologies

Epigenetic pathways play a critical role in the initiation, progression, and metastasis of cancer. Over the past few decades, significant progress has been made in the development of targeted epigenetic modulators(e.g., inhibitors). However, epigenetic inhibitors have faced multiple challenges,including limited clinical efficacy, toxicities, lack of subtype selectivity, and drug resistance. As a result,the design of new epigenetic modulators(e.g., degraders) such as PROTACs, molecular glue, and hydrophobic tagging(Hy T) degraders has garnered significant attention from both academia and pharmaceutical industry, and numerous epigenetic degraders have been discovered in the past decade. In this review,we aim to provide an in-depth illustration of new degrading strategies(2017-2023) targeting epigenetic proteins for cancer therapy, focusing on the rational design, pharmacodynamics, pharmacokinetics, clinical status, and crystal structure information of these degraders. Importantly, we also provide deep insights into the potential challenges and corresponding remedies of this approach to drug design and development. Overall, we hope this review will offer a better mechanistic understanding and serve as a useful guide for the development of emerging epigenetic-targeting degraders.

Design and fabrication of high-performance injectable self-setting trimagnesium phosphate

Magnesium phosphate bone cement has become a widely used orthopedic implant due to the advantages of fast-setting and high early strength. However, developing magnesium phosphate cement possessing applicable injectability, high strength, and biocompatibility simultaneously remains a significant challenge. Herein, we propose a strategy to develop high-performance bone cement and establish a trimagnesium phosphate cement (TMPC) system. The TMPC exhibits high early strength, low curing temperature, neutral pH, and excellent injectability, overcoming the critical limitations of recently studied magnesium phosphate cement. By monitoring the hydration pH value and electroconductivity, we demonstrate that the magnesium-to-phosphate ratio could manipulate the components of hydration products and their transformation by adjusting the pH of the system, which will influence the hydration speed. Further, the ratio could regulate the hydration network and the properties of TMPC. Moreover, in vitro studies show that TMPC has outstanding biocompatibility and bone-filling capacity. The facile preparation properties and these advantages of TMPC render it a potential clinical alternative to polymethylmethacrylate and calcium phosphate bone cement. This study will contribute to the rational design of high-performance bone cement.

牦牛巴氏杆菌病和牛病毒性腹泻病流行情况分析

为掌握日喀则市牦牛巴氏杆菌病和牛病毒性腹泻病的流行情况,研判当前该区域内牦牛发病趋势,为进一步优化当前区域内牦牛疫病防控策略提供依据和建议。针对区域内牦牛个体进行抽样,用实验室检测技术开展牦牛巴氏杆菌抗体、牛病毒性腹泻病毒抗原、细菌培养鉴定、病原核酸检测等项目。针对疑似发病个体开展相关病原学检测,结合当地动物疫病防控工作历史经验,对检测结果进行研究分析。随机抽样检测结果显示,牦牛巴氏杆菌病抗体阳性率12.43%,牛病毒性腹泻抗原阳性率9.04%,牛巴氏杆菌细菌培养分离鉴定阳性率为0,牛巴氏杆菌核酸检测阳性率为0,牛病毒性腹泻核酸检测阳性率为0;发病牛群采样检测结果显示10头牛感染牛病毒性腹泻病毒,其中2头可能同时感染牛巴氏杆菌病。结果表明牦牛巴氏杆菌病以及牛病毒性腹泻在相关区域内广泛存在,牛病毒性腹泻病毒感染是导致当前该区域牦牛发病的主要原因,要进一步加强牛巴氏杆菌病和牛病毒性腹泻病的鉴别诊断,优化调整当前疫病防控策略,转变传统防控思维,消灭相关病原传播的风险因素。

土壤中拮抗菌株铜绿假单胞菌HBD-12次级代谢产物的分离鉴定及其体外抗菌抗肿瘤活性检测

为从土壤中筛到具有抗菌和抗肿瘤等生物活性的菌株,以孕烯醇酮作为唯一碳源进行筛菌,经分子生物学鉴定及菌株发酵液抑菌活性测定,发现一株铜绿假单胞菌HBD-12对大肠杆菌、苏云金芽孢杆菌、指状青霉、意大利青霉具有较好抑菌效果。运用柱层析法分离纯化该菌株发酵液成分,采用波谱法解析所得单体化合物结构,并使用HTRF激酶检测试剂盒测定其抗肿瘤活性。结果显示:分离得到的单体化合物1-羟基-9,10-二氮杂菲和3-羟基-9,10-二氢二氮杂菲均具有显著的抗肿瘤活性。在浓度为20μg/mL时,1-羟基-9,10-二氮杂菲和3-羟基-9,10-二氢二氮杂菲对Aurora激酶A的抑制率分别为78.39%±2.29%和60.34%±8.35%。由此可见该菌株的次级代谢产物对新型抗菌、抗肿瘤药物的研发具有很好的利用价值。

垃圾堆积点土壤中广谱拮抗菌株的分离鉴定及抑菌特性

[目的]从积年垃圾堆积点土壤中筛选具有高效抑菌能力的广谱拮抗菌株并研究其抑菌特性,寻找乡镇垃圾堆积点污染治理的新思路。[方法]采用平板稀释法和管碟法从乡镇积年垃圾堆积点的土壤中分离拮抗真菌,并通过形态观察、生理生化特性及分子生物学鉴定分析对拮抗菌株进行鉴定。通过测定抑菌活性物质的极性,选择合适的有机试剂对拮抗真菌的发酵菌体甲醇浸提物及发酵液进行萃取,并利用TLC-Bioautography法对发酵液及发酵菌体中的抑菌活性组分进行分析。使用23种指示菌测定拮抗真菌DAZ-2的发酵菌体乙酸乙酯粗提物的抑菌广谱,测定粗提物在高温、酸碱、紫外和自然光条件下抑菌能力,以及对大肠杆菌和白色念珠球菌的最小抑菌浓度。[结果]分离得到一株传代稳定的广谱拮抗真菌DAZ-2,经过形态观察、生理生化特性测定及ITS序列分析,菌株鉴定为Aspergillus fumigatus。通过极性测定,选择乙酸乙酯对烟曲霉DAZ-2发酵菌体甲醇浸提物及发酵液进行萃取,TLC-Bioautography法分析表明两者中的抑菌活性物质不是同一组分,且存在多组分物质共同作用产生抑菌效果的可能性;菌体浸提物乙酸乙酯萃取部分(200μg/mL)对11种指示菌具有抑菌效果,对大肠杆菌和白色念珠球菌的MIC为7.50μg/mL和15μg/mL,且对高温、酸碱、紫外、自然光照都具有较强的稳定性。[结论]分离得到一株高效抑菌且传代稳定的广谱拮抗菌株烟曲霉DAZ-2,有希望为微生物药物的开发和乡镇垃圾堆积点污染治理提供科学依据。