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"Li, Xian"
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Initiation of the Indosinian Orogeny in South China: Evidence for a Permian Magmatic Arc on Hainan Island
It has been widely accepted that an active continental margin existed along the coast of Southeast China during the Mesozoic time that produced extensive magmatism in the region. However, there is little constraint as to when this active margin was first initiated. Here we present new SHRIMP U‐Pb zircon ages and geochemical and Sr‐Nd isotopic data for syntectonic granites on Hainan Island. Our data demonstrate that these rocks, dated at 267–262 Ma, are typical of calc‐alkaline I‐type granites formed in continental arc environments. The age of this magmatic arc coincides with a sudden change in sedimentary environments in South China during the Permian time, suggesting that the South China Indosinian Orogeny was likely contemporaneous with the onset of continental arc magmatism.
Journal Article
الثقة في النظرية : نجاح لنظام التنمية (البديل) الخاص بالصين
جاء هذا الكتاب تحت عنوان «الثقة في النظرية : نجاح لنظام التنمية \"البديل\" الخاص بالصين» وهو من تأليف (مايا غيو) وترجمة عبد الرحمن النجار. يبحث الكتاب في التطور الصيني السريع خلال الستة عقود الماضية، والدور الذي لعبه الحزب الشيوعي الصيني في تحويل الصين إلى دولة اشتراكية حديثة مزدهرة وقوية وديمقراطية ومتطورة ثقافيا ويستكشف ويستكشف فيما إذا كان صعود الصين يهدد نموذج التنمية الغربي وخاصة بعد أن أضحى صعود الصين حقيقة لا جدال فيها. يعتبر هذا الكتاب من أنجح الكتب التي نشرت عن الصين اليوم. فهو يقدم حججا مقنعة حول نهوض الصين. وتستند الآراء المعبر عنها في الكتاب ليس فقط إلى 60 عاما من تاريخ جمهورية الصين الشعبية وإنجازاتها الملحوظة في العقود الثلاثة الماضية، ولكن أيضا على تاريخها الحديث منذ عام 1840، وتاريخها الذي دام 2000 عام كدولة موحدة، وحضارتها ذات ال 5000 سنة. وتعكس المقابلات التي أجرتها المؤلفة \"مايا غيو\" مراقبتها الدقيقة للصين اليوم. إذ تضمنت أشخاصا من دوائر مختلفة، تشمل مجالات خبرتهم السياسة والاقتصاد والمجتمع والوضع الوطني وتاريخ دبلوماسية الحزب الشيوعي الصيني والاستراتيجية العسكرية وإدارة ممتلكات الدولة والرعاية الصحية والأعمال التجارية الخاصة. وتختلف موضوعات المقابلات على نطاق واسع؛ فمن النظم والنظرية والتطوير والإصلاح، إلى نوعية الحياة والاستراتيجية والدبلوماسية وجميع من كان فيها يؤيدون التعلم من الحضارات الإنسانية، ولكنهم يصرون في الوقت نفسه على ضرورة اتخاذ مسار يناسب الصين بدلا من استنساخ النموذج الغربي. يأتي هذا الكتاب من ضمن سلسلة تتألف من ثلاثة كتب وهي : الثقة في المسار : نموذج جديد لقوة صاعدة، الثقة في النظرية : فلسفة الصين لنظام دولي جديد، والثقة في النظام : نجاح نظام التنمية \"البديل\" في الصين. بما يوفر للقارئ مقاربة نظرية وواقعية لمسار الصين ونظريتها ونظامها، ويشرح أسباب ثقة الدولة الصينية في خياراتها.
Book
Targeting CD39 in cancer
The ATP–adenosine pathway functions as a key modulator of innate and adaptive immunity within the tumour microenvironment. Consequently, multiple clinical strategies are being explored to target this pathway for the treatment of cancer; in particular, recent clinical data with CD73 antagonists and inhibitors of A2A receptors have demonstrated the therapeutic potential of modulating this pathway. Now, inhibitors of the ectonucleotidase CD39, the rate-limiting enzyme in the conversion of ATP to immunomodulatory adenosine, are entering clinical trials. Consequently, there is currently a focus on understanding the impact of CD39 enzymatic function on innate and adaptive immunity and how therapeutic modulation of this pathway alters their functional potential within the tumour microenvironment. Recent findings reveal multipronged mechanisms of action of CD39 antagonism that rely not only on preventing the accumulation of adenosine but also on the stabilization of pro-inflammatory extracellular ATP to restore antitumour immunity. Here, we review the impact of CD39 expression and ectonucleotidase activity on immunity with a focus on the setting of oncology. Additionally, we discuss the implications for immunotherapy strategies targeting CD39, including their inclusion in rational combination therapies.The ATP–adenosine pathway plays an important role in modulating innate and adaptive immune responses in the tumour microenvironment. Here, the authors focus on CD39, a key enzyme in the ATP–adenosine pathway, and examine immunotherapeutic strategies that target it.
Journal Article
Two-billion-year-old volcanism on the Moon from Chang’e-5 basalts
The Moon has a magmatic and thermal history that is distinct from that of the terrestrial planets
1
. Radioisotope dating of lunar samples suggests that most lunar basaltic magmatism ceased by around 2.9–2.8 billion years ago (Ga)
2
,
3
, although younger basalts between 3 Ga and 1 Ga have been suggested by crater-counting chronology, which has large uncertainties owing to the lack of returned samples for calibration
4
,
5
. Here we report a precise lead–lead age of 2,030 ± 4 million years ago for basalt clasts returned by the Chang’e-5 mission, and a
238
U/
204
Pb ratio (
µ
value)
6
of about 680 for a source that evolved through two stages of differentiation. This is the youngest crystallization age reported so far for lunar basalts by radiometric dating, extending the duration of lunar volcanism by approximately 800–900 million years. The
µ
value of the Chang’e-5 basalt mantle source is within the range of low-titanium and high-titanium basalts from Apollo sites (
µ
value of about 300–1,000), but notably lower than those of potassium, rare-earth elements and phosphorus (KREEP) and high-aluminium basalts
7
(
µ
value of about 2,600–3,700), indicating that the Chang’e-5 basalts were produced by melting of a KREEP-poor source. This age provides a pivotal calibration point for crater-counting chronology in the inner Solar System and provides insight on the volcanic and thermal history of the Moon.
Basalt samples returned from the Moon by the Chang’e-5 mission are revealed to be two billion years old by radioisotopic dating, providing insight on the volcanic history of the Moon.
Journal Article
Giant negative magnetoresistance induced by the chiral anomaly in individual Cd3As2 nanowires
Dirac electronic materials beyond graphene and topological insulators have recently attracted considerable attention. Cd
3
As
2
is a Dirac semimetal with linear dispersion along all three momentum directions and can be viewed as a three-dimensional analogue of graphene. By breaking of either time-reversal symmetry or spatial inversion symmetry, the Dirac semimetal is believed to transform into a Weyl semimetal with an exotic chiral anomaly effect, however the experimental evidence of the chiral anomaly is still missing in Cd
3
As
2
. Here we show a large negative magnetoresistance with magnitude of −63% at 60 K and −11% at 300 K in individual Cd
3
As
2
nanowires. The negative magnetoresistance can be modulated by gate voltage and temperature through tuning the density of chiral states at the Fermi level and the inter-valley scatterings between Weyl nodes. The results give evidence of the chiral anomaly effect and are valuable for understanding the Weyl fermions in Dirac semimetals.
Dirac semimetals possess an electronic dispersion relation which is linear in three dimensions, making them three-dimensional analogues of graphene. Here, the authors report large negative magnetoresistance in single-crystal Cd
3
As
2
nanowires, evidencing a sought-after chiral anomaly effect.
Journal Article
Efflux-Mediated Drug Resistance in Bacteria
Drug efflux pumps play a key role in drug resistance and also serve other functions in bacteria. There has been a growing list of multidrug and drug-specific efflux pumps characterized from bacteria of human, animal, plant and environmental origins. These pumps are mostly encoded on the chromosome, although they can also be plasmid-encoded. A previous article in this journal provided a comprehensive review regarding efflux-mediated drug resistance in bacteria. In the past 5 years, significant progress has been achieved in further understanding of drug resistance-related efflux transporters and this review focuses on the latest studies in this field since 2003. This has been demonstrated in multiple aspects that include but are not limited to: further molecular and biochemical characterization of the known drug efflux pumps and identification of novel drug efflux pumps; structural elucidation of the transport mechanisms of drug transporters; regulatory mechanisms of drug efflux pumps; determining the role of the drug efflux pumps in other functions such as stress responses, virulence and cell communication; and development of efflux pump inhibitors. Overall, the multifaceted implications of drug efflux transporters warrant novel strategies to combat multidrug resistance in bacteria.
Journal Article
Synthesis and macrocyclization-induced emission enhancement of benzothiadiazole-based macrocycle
We presented an effective and universal strategy for the improvement of luminophore’s solid-state emission, i.e., macrocyclization-induced emission enhancement (MIEE), by linking luminophores through C(sp
3
) bridges to give a macrocycle. Benzothiadiazole-based macrocycle (BT-LC) has been synthesized by a one-step condensation of the monomer 4,7-bis(2,4-dimethoxyphenyl)−2,1,3-benzothiadiazole (BT-M) with paraformaldehyde, catalyzed by Lewis acid. In comparison with the monomer, macrocycle BT-LC produces much more intense fluorescence in the solid state (
Φ
PL
= 99%) and exhibits better device performance in the application of OLEDs. Single-crystal analysis and theoretical simulations reveal that the monomer can return to the ground state through a minimum energy crossing point (MECP
S1/S0
), resulting in the decrease of fluorescence efficiency. For the macrocycle, its inherent structural rigidity prohibits this non-radiative relaxation process and promotes the radiative relaxation, therefore emitting intense fluorescence. More significantly, MIEE strategy has good universality that several macrocycles with different luminophores also display emission improvement.
Organic luminescent materials attract attention due to their wide application range, but many organic luminogens suffer from severe quenching effect in the aggregate state. Here, the authors demonstrate a macrocyclization induced emission enhancement by linking luminophores through methylene bridges to give a macrocycle.
Journal Article
Aharonov–Bohm oscillations in Dirac semimetal Cd3As2 nanowires
Three-dimensional Dirac semimetals, three-dimensional analogues of graphene, are unusual quantum materials with massless Dirac fermions, which can be further converted to Weyl fermions by breaking time reversal or inversion symmetry. Topological surface states with Fermi arcs are predicted on the surface and have been observed by angle-resolved photoemission spectroscopy experiments. Although the exotic transport properties of the bulk Dirac cones have been demonstrated, it is still a challenge to reveal the surface states via transport measurements due to the highly conductive bulk states. Here, we show Aharonov–Bohm oscillations in individual single-crystal Cd
3
As
2
nanowires with low carrier concentration and large surface-to-volume ratio, providing transport evidence of the surface state in three-dimensional Dirac semimetals. Moreover, the quantum transport can be modulated by tuning the Fermi level using a gate voltage, enabling a deeper understanding of the rich physics residing in Dirac semimetals.
Dirac semimetals are a three-dimensional analogue of graphene that can support massless Dirac fermions in their bulk and Fermi-arc surface states. Here, the authors observe Aharonov–Bohm oscillations in transport measurements on Cd
3
As
2
nanowires, revealing these exotic surface states.
Journal Article