永无止境
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A | The Earth is moving away from the Sun, but don’t expect any cooler temperatures because of it. According to Livescience, the Earth’s average distance from the Sun is increasing, but at a very slow rate of about 2.36 inches a year. That pales in comparison to the variations in the distance between the Earth and the Sun that happens annually because of the planet’s elliptical orbit.,At different times of the year, the Earth can be as little as 91.4 million miles away from the Sun and as much as 94.5 million miles. That 3.1 million mile fluctuation dwarfs any increase that comes from Earth’s growing orbit.,The reason why the Earth is moving away from the largest body in our solar system shows that the solar system is aging. The primary driver behind the movement is the Sun's continuous loss of mass. The Sun runs off of nuclear fusion, which converts its mass into energy that powers life on Earth. Thanks to Einstein, we know that matter and energy cannot be destroyed or created, only converted, which means the Sun’s mass is continually depleting. It will eventually lose 0.1% of its mass before it begins its death cycle billions of years into the future.,Science & TechEarth Beats Own Rotation Record by Ending a 'Day' 1.59ms Faster3 August, 12:51 GMT,While 0.1% sounds like an insignificant number, given the massive size of the Sun, it isn’t. It is equivalent to the entire mass of Jupiter, the largest planet in our solar system, and roughly 318 times the entire mass of Earth. Gravity is determined by the mass of an object so less mass means the Sun’s pull on the Earth is getting slightly weaker over time.,There is another factor, the Earth itself. Just like the gravity from the moon causes the tides of the oceans to rise and fall, Earth’s gravity affects the Sun as well. Its pull causes mass from the Sun to bulge out slightly towards the planet, helping move the Earth along its orbit and further away from the Sun. That movement is even more insignificant than the movement from the loss of the Sun’s mass, it is causing the Earth to move 0.0001 inches away from the Sun annually.,All things being equal, this movement would help lower temperatures slightly after a billion years, with about 0.4% less of the Sun’s energy hitting the Earth after that time. But that will be far less than normal variations in the Sun’s brightness and will be more than offset by the phases in the Sun’s life cycle. Every billion years the Sun is expected to get 6% brighter for the next 5 billion years. After that time, it will run low on hydrogen fuel and begin to bloat into a red giant star.,By that time, the Sun will have already boiled away Earth’s oceans and rendered the planet inhabitable. Most models predict that once the Sun becomes a red giant it will engulf the planet. A few models suggest the planet may survive just outside of the Sun’s reach, but it will be a boiling mass of molten hot lava.,If humans are around at that point, they will have to have mastered planet-moving technologies, if they want to keep the Earth around.。 这种蛋白质被称为SHMOOSE，是一种微小的"微蛋白"，由细胞内产生能量的线粒体中一个新发现的基因编码。
B | 该基因的突变使SHMOOSE微蛋白部分失活，并与四个不同队列中的阿尔茨海默病风险增加30%有关。据研究人员称，几乎25%的欧洲血统的人有这种蛋白质的突变版本。阿尔茨海默病是最普遍的痴呆症类型。这是一种渐进式的疾病，从轻微的记忆丧失开始，可能会导致丧失进行对话和对环境做出反应的能力。根据美国疾病控制与预防中心（CDC）的数据，在2020年，多达580万美国人患有阿尔茨海默病。这项研究于9月21日发表在《分子精神病学》杂志上。研究人员表示，这种以前未被发现的突变的巨大风险和高流行率都使它与其他涉及阿尔茨海默病的蛋白质有所区别。除了APOE4--这种疾病最有力的已知遗传风险因素--只有数量有限的其他基因突变被发现，而且这些突变只轻微地增加了不到10%的风险。此外，由于微蛋白的大小与胰岛素肽差不多，它可以很容易地被施用。这大大增加了它的治疗潜力。Pinchas Cohen说：“这一发现为开发基于精准医疗的阿尔茨海默病疗法开辟了令人兴奋的新方向，重点是将SHMOOSE作为一个目标领域。”他是这项研究的资深作者，也是老年学、医学和生物科学的教授。“对携带突变和产生突变蛋白的个体施用SHMOOSE类似物，可能证明对神经退行性疾病和其他衰老疾病有好处。”南加州大学神经科学博士毕业生Brendan Miller是该研究的第一作者。他利用大数据技术确定线粒体DNA中与疾病风险相关的基因变异。在分析发现一个基因突变增加了阿尔茨海默病风险、大脑萎缩和能量代谢后，Miller和他的同事发现突变的基因编码为SHMOOSE微蛋白，并开始研究其突变和默认形式。研究人员说，SHMOOSE是第一个用抗体和质谱法检测的线粒体DNA编码的微蛋白。看起来这种微蛋白修改了中枢神经系统的能量信号和新陈代谢。它在神经元的线粒体中被发现，其在脑脊液中的水平与阿尔茨海默病的生物标志物相关。各种细胞培养和动物实验表明，SHMOOSE部分通过栖息在线粒体的一个关键部分，即线粒体内膜，改变了大脑的能量代谢。阿尔茨海默病目前在美国被列为第六大死因。然而，CDC最近的估计表明，这种疾病可能排在第三位，仅次于心脏病和癌症，是老年人死亡的原因之一。尽管目前还没有治愈阿尔茨海默氏病的方法，但近年来在开发和测试新的治疗方法方面取得了重大进展。
C | 一个新兴的研究领域据Miller说，这些发现突出了微蛋白这一相对较新的领域的重要性。几十年来，科学家们主要通过考虑一组2万个大型蛋白质编码基因来研究生物学。
D | 然而，还有数十万个可能的编码微小微蛋白的基因已经被现代技术所揭示。Miller表示：“微蛋白领域仍然是如此的新。我们还不知道有多少微蛋白基因甚至是有功能的，而且从成千上万的名单中逐一研究潜在的微蛋白的成本实在是太昂贵和低效。我和我的同事用来检测SHMOOSE的方法显示了将大的遗传学数据与分子和生物化学技术相结合以发现功能性微蛋白的力量。
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