News on China's scientific and technological development.

NiuBiDaRen

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“My dream is that after the joint efforts of our generation and generations, after ten or twenty years, Shenzhen will occupy an important place in the world biomedical map; When everyone talks about the Greater Bay Area of biomedicine, the first thing that will come to mind is here in the Eastern Hemisphere!”

Nice
 

xlitter

Junior Member
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Something really strange happened today. Wonder everyone else's thoughts on this are

3 big tech got into JVs with 3 of the largest SOE tech firms. What's going on?
Only the cooperation of China Unicom is real, it is just a joint venture company, mainly engaged in the content distribution network (CDN) and edge computing business

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xlitter

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DJI is not the only success drone company.

Looks like Feiyu here is quite a success too. Their products are a little more expensive.
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There are more than 12,000 civilian drone companies in China, with a total output value of 87 billion yuan. Among them, there are more than 1,500 in Shenzhen alone, with an output value of nearly 60 billion yuan. In terms of industrial drones, China accounts for about 55% of the global market, and for consumer drones, China accounts for 74% of the global market. Industry insiders said that due to the expansion of demand for contactless distribution and intelligent applications in the past two years, the drone industry has maintained a rapid annual growth rate of about 30%. It is expected that the output value of the domestic drone industry will exceed 100 billion yuan in 2022.
 

SanWenYu

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Northwestern Polytechnical University made breakthrough in creating ultra strong "eutectic high-entropy alloys (EHEA)".

"Our phase-selectively recrystallized EHEA achieves a high ductility of ∼35% uniform elongation with true stress of ∼2 GPa."

Such alloys will have wide uses in "shields of spacecrafts" and "high end armours".

Paper in English:
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Abstract​

Excellent ductility is crucial not only for shaping but also for strengthening metals and alloys. The ever most widely used eutectic alloys are suffering from the limited ductility and losing competitiveness among advanced structural materials. Here we report a distinctive concept of phase-selective recrystallization to overcome this challenge for eutectic alloys by triggering the strain hardening capacity of the duplex phases completely. We manipulate the strain partitioning behavior of the two phases in a eutectic high-entropy alloy (EHEA) to obtain the phase-selectively recrystallized microstructure with a fully recrystallized soft phase embedded in the skeleton of a hard phase. The resulting microstructure fully releases the strain hardening capacity in EHEA by eliminating the weak boundaries. Our phase-selectively recrystallized EHEA achieves a high ductility of ∼35% uniform elongation with true stress of ∼2 GPa. This concept is universal for various duplex alloys with soft and hard phases and opens new frontiers for traditional eutectic alloys as high-strength metallic materials.

News report in Chinese:
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西工大在双相合金强韧化方面研究取得突破性进展​

中新网西安11月3日电 (记者 阿琳娜)记者3日从西北工业大学获悉,该校科研团队在双相合金强韧化方面研究取得突破性进展,提出了双相合金的相选择再结晶概念,实现了双相合金力学性能的显著提升。这一研究成果,让人类制造出密度低、强度高,且具有良好变形能力的合金材料,不再只是幻想。

据介绍,一般而言,自然界中存在的材料,要么“强而脆”,要么“软而韧”,因此,研制出“强且韧”的材料是材料科学家永恒的追求。

金属材料因强度高且具备一定韧性,已经被大量应用于对安全系数要求高的结构件中。比如,现在汽车由金属材料制备的笼式结构,即便受到一定程度的撞击发生变形,也不会完全断裂,从而保护驾乘人员的生命安全。那么,在更极端的环境中,金属材料是否还能满足使用要求呢?

西工大材料学院教授王志军介绍:“举个极端的例子,比如空间站受到太空垃圾的‘袭击’时,太空垃圾会以每秒10公里左右的速度冲向空间站,普通的金属材料会瞬间被击穿。”

从理论上讲,空间站的防护屏障所选用的材料,既要有极高的强度,又要有很高的韧性,同时还要轻便易运输。不仅如此,太空中还有宇宙射线和高低温交替,在这种极端环境下,金属材料也要保持很好的性能。

这就为材料科学家提出了一个非常具有挑战性的课题。从目前金属材料的科学研究来看,使用既强又韧的金属材料,是被动防护的最佳选择之一。

尽管目前空间站中使用的材料是可以防范以上风险的,不过,科学家们还是在不断追求更轻、更高效、更节能环保、更容易制备的合金材料。

西北工业大学材料学院王锦程教授团队,在双相合金中提出的选“相”再结晶概念,为科学家们研制出密度低、强度高,且具有良好变形能力的合金材料提供了理论支撑。

什么是双相金属材料?团队何峰教授打了个比方:“我们可以把双相金属材料中的两个决定其性能的结构(双相),分别比喻为动物的骨骼和肌肉,只有在骨骼强硬、肌肉发达,且软组织柔韧的情况下,一个动物才能有很好的运动能力。”

理论上来讲,双相合金因为具备“骨骼”和“肌肉”协调运行的基本要素,因此理应具有很好的性能。然而,传统双相合金因为受制于加工工艺的限制,“骨骼”之间的连接薄弱,容易“脱臼”,且“骨骼”与“肌肉”之间不能良好协作,因此在真实应用场景下,双相合金的性能总是与理论设想中的相去甚远。

针对这一难题,团队提出了一种独特的“相”选择再结晶概念,让双相合金的“骨骼”韧性更高,“肌肉”和“骨骼”的协调性更好,从根本上消除“脱臼”的可能性。这种方法首次在共晶高熵合金中实现了高达35%的均匀延伸率,并实现了接近2GPa的断裂真应力。

王锦程表示,相对于传统强韧化方案,团队创新提出的新方法,不仅工艺简单,更重要的是调控后的合金强塑性得到了成倍的突破,未来有望在空天防护、高端装甲中获得广泛应用。

何峰表示:“如果有了这样的防护装备,未来,太空旅行的安全指数将大大提高。”(完)
 

SanWenYu

Captain
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Tianjing University made natural cocoon silk into ultra strong artificial fiber that is 70% stronger spider silk. Spider silk, known as the strongest natural protain fiber so far, is 5 to 10 times stronger than steel of same weight.

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超强人造蚕丝在天津大学诞生​

中新网天津11月3日电 (孙玲玲 焦德芳 李晴)记者从天津大学获悉,日前,天津大学生命科学学院林志教授团队提出超强人造蚕丝制备新方法,首次将廉价的普通蚕丝转换成具有超高强度的人造蚕丝。相关成果已发表在国际著名材料学期刊《物质》。

天然蜘蛛牵引丝是自然界已知强度最高的天然蛋白纤维,其强度是同质量钢的五到十倍。然而,由于从天然蜘蛛中取得大批量蛛丝十分困难,目前市场上很少出现与蛛丝相关的实际产品。人类有利用蚕丝的悠久历史,但相较于蛛丝,蚕丝的强度和韧性都远远不够,学界一直致力于以蚕丝为出发点制造更坚韧的丝线,但以往得到的人造丝线大多性能不佳。

天然蜘蛛牵引丝是自然界已知强度最高的天然蛋白纤维,其强度是同质量钢的五到十倍。然而,由于从天然蜘蛛中取得大批量蛛丝十分困难,目前市场上很少出现与蛛丝相关的实际产品。人类有利用蚕丝的悠久历史,但相较于蛛丝,蚕丝的强度和韧性都远远不够,学界一直致力于以蚕丝为出发点制造更坚韧的丝线,但以往得到的人造丝线大多性能不佳。

“丝素蛋白是从蚕丝中提取的天然高分子纤维蛋白,相对于降解严重的蛋白,完整的高分子量丝素蛋白分子链可以提高纤维的强度。”据林志教授介绍,他带领团队使用了十二烷基硫酸钠和碳酸钠辅助溶解蚕丝外部粘层的方法,该方法的蚕茧脱胶率在28%左右,并且得到的再生丝素蛋白分子量仍较大,一定程度上保障了其机械性能。人工纺丝时,研究人员将浓缩的再生丝素蛋白通过微管像挤牙膏一样挤出,挤出的蛋白在含有锌离子和铁离子的溶液中迅速凝固形成细长的纤维,再经过适当的后处理,得到的纤维直径与蜘蛛牵引丝类似,但其强度和硬度都显著优于天然牵引丝。

据介绍,这种人工蚕丝纤维的拉伸强度比天然蛛丝的平均强度要高70%以上,远远高于所有已知的天然微丝,成为了一种前景广阔的“超强人造蚕丝”。“这项成果为生产高性能人造丝开辟了一种便捷高效的途径,为大规模生产具有高性能的蚕丝纺织品材料提供了坚实的技术基础。”林志表示。(完)
 

SanWenYu

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After years of hard work, scientists from Nanjing Medical University found a way to make "fast-onset" new antidepressant drugs. Their work is considered a major breakthrough in antidepressant research in the past 60 years.

Paper in English:
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A new class of antidepressant drugs​

Presently available antidepressant drugs have unpleasant side effects, addictive properties, or can induce schizophrenia. Developing fast-onset antidepressants without these drawbacks is thus an important neuropharmacological goal. Sun et al. discovered that dissociating the serotonin transporter from nitric oxide synthase specifically reduced intercellular serotonin concentration in a brain region called the dorsal raphe nucleus. Disrupting this interaction enhanced serotonergic neuron activity in this area and dramatically promoted serotonin release into the medial prefrontal cortex, thereby producing a fast-onset antidepressant effect. A small-molecule blocker of the nitric oxide synthase–serotonin transporter interaction had a fast-onset antidepressant effect in an animal model. —PRS

Abstract​

Major depressive disorder (MDD) is one of the most common mental disorders. We designed a fast-onset antidepressant that works by disrupting the interaction between the serotonin transporter (SERT) and neuronal nitric oxide synthase (nNOS) in the dorsal raphe nucleus (DRN). Chronic unpredictable mild stress (CMS) selectively increased the SERT-nNOS complex in the DRN in mice. Augmentation of SERT-nNOS interactions in the DRN caused a depression-like phenotype and accounted for the CMS-induced depressive behaviors. Disrupting the SERT-nNOS interaction produced a fast-onset antidepressant effect by enhancing serotonin signaling in forebrain circuits. We discovered a small-molecule compound, ZZL-7, that elicited an antidepressant effect 2 hours after treatment without undesirable side effects. This compound, or analogous reagents, may serve as a new, rapidly acting treatment for MDD.

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抗抑郁药研究领域取得重大突破,或能克服现有药物副作用​

近日,南京医科大学生殖医学国家重点实验室、药学院周其冈教授、朱东亚教授、厉廷有教授联合研究团队发现了一个能够开发快速抗抑郁药物的新靶点,并合成了一种能够快速起效的候选抗抑郁先导化合物,能克服现有抗抑郁药物的多个副作用,有望成为新一代抗抑郁药物的候选药物。相关研究成果已在国际学术期刊《科学》上发表。

目前学界公认的抑郁症主要致病机制是大脑中神经元突触间隙的5-羟色胺神经递质减少。作为神经递质的种类之一,5-羟色胺主要介导人类的抑郁情绪,增高突触间隙的5-羟色胺浓度能够发挥抗抑郁作用,这便是沿用至今近60年的“单胺假说”。

研究团队介绍道:“自20世纪50年代抗抑郁药物被发现以来,第一代、第二代抗抑郁药物都存在较多、较严重的副作用。以‘单胺假说’为理论基础的第三代抗抑郁药物于20世纪80年代上市,至今仍应用于临床一线。”比如经典抗抑郁药物氟西汀——就是人们熟知的百忧解,就是基于“单胺假说”研发出来的。

“但是大脑很神奇,脑干处还有一个非常特异的核团叫做中缝背核,大量的5-羟色胺在这里合成再通过神经元发射到全脑。”周其冈教授解释道,“大脑有负反馈机制,5-羟色胺转运子抑制剂在突触和脑干处发挥的作用完全是相反的,在5-羟色胺转运子抑制剂用药早期,两方面的平衡作用导致了无法发挥抗抑郁疗效。需要等到中缝背核5-羟色胺自身受体脱敏后,氟西汀等药物才能显现抗抑郁效果。”

这也正是为什么,抑郁症患者服药后,仍会出现文章开篇所述的情况:见效慢,极少数人服用后还会加重病情甚至诱发自杀。

团队经过多年研究,发现了一个抗抑郁的新靶点,即位于中缝背核区的5-羟色胺转运体与神经元型一氧化氮合酶耦联靶点。解开SERT-nNOS耦联,能不依赖于5-羟色胺自身受体脱敏,发挥快速抗抑郁作用。基于此,研究团队合成了一种快速起效的抗抑郁先导化合物“ZZL-7”。小鼠实验显示,“ZZL-7”在注射后2小时发挥抗抑郁作用。

这一新发现不仅阐明了基于“单胺假说”的药物延迟起效的根本原因,也通过新靶点实现了短时间快速起效,在理论意义上实现完全克服以往药物副反应缺陷的可能。国际学术界评价认为,此次研究成果改写了单胺抗抑郁药物只能慢性起效的传统认识,是“单胺假说”提出近60年、第三代抗抑郁药物上市近40年来,抗抑郁药物研究领域的重大理论突破。

“我们要做的还有很多,从靶点的发现到真正药物上市往往还需要10-15年的时间。”周其冈教授表示,“未来我们将以ZZL-7为母核结构,进一步研究并筛选出活性更高、成药性好的化合物,努力发展新一代抗抑郁药物。”
 
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