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Science & technology
科技版块
Contraception
避孕
Tubular gels
管状凝胶
Researchers want to make reversible vasectomies a one shot deal
研究人员希望使可逆输精管切除术成为一种一次性解决方案
The most reliable means of contraception for men--and one that cannot fail or be forgone in the heat of the moment--is a vasectomy.
对男性来说，最可靠的避孕方法是输精管结扎术，这是一种不会在一时的狂热中失败的方法。
But the procedure is largely irreversible: it involves stopping the flow of sperm from the testes by cutting conduits known as the vas deferens and sealing them or tying them off.
但这一过程在很大程度上是不可逆转的：它包括通过切割被称为输精管的管道来阻止精子从睾丸流出，并将它们密封或打结。
A reconnection, after a reconsideration, is no small task.
在重新考虑之后，重新建立联系并不是一项小任务。
Researchers are now examining a different tack: blocking the vas deferens using compounds that combine to form a barrier that can later be removed.
研究人员现在正在研究一种不同的方法：使用化合物来堵塞输精管，这些化合物结合在一起形成一道屏障，以后可以被移除。
Lab trials have involved four separate injections to establish a sperm-proof barrier, which could later be dissolved using a blast of focused, infrared light.
实验室试验包括四次单独的注射，以建立防精子屏障，之后可以用一束聚焦的红外光来溶解它。
Aware that repeated injections into the penis might affect men’s willingness to undergo such a procedure, Wanhai Xu, a urologist at Harbin Medical University in China, and colleagues propose a different idea: a barrier that can be put in place with one injection and broken down with ultrasound.
中国哈尔滨医科大学的泌尿科医生徐万海和他的同事们意识到，阴茎反复注射可能会影响男性接受这种手术的意愿，因此他们提出了一个不同的想法：只需注射一次就能建立屏障，然后通过超声波消除。
Dr Xu’s recipe includes three parts, principally a polymer known as a hydrogel that thickens inside the body and is already approved for medical use.
徐博士的方法包括三个部分，主要是一种被称为水凝胶的聚合物，它会在体内增稠，已经被批准用于医疗用途。
Crucially, in that gel were plenty of thioketals, compounds that fall apart when exposed to reactive, oxygen-containing molecules, plus just a sprinkle of titanium dioxide--an inert material that, when exposed to ultrasound, releases just those molecules.
至关重要的是，这种凝胶中含有大量的硫酮化合物，这种化合物接触到活性的含氧分子就会分解，外加少量二氧化钛--一种惰性物质，暴露在超声波下时，这些分子就会被释放。
To check their work, Dr Xu’s team employed a few dozen male rats.
为了检验他们的工作，徐博士的团队使用了几十只雄性老鼠做实验。
Some were given a traditional vasectomy, others an injection of the new material and the rest injected with saline, as a control.
一些老鼠接受了传统的输精管结扎术，另一些注射了新材料，其余的注射了生理盐水作为对照。
Each was then permitted to follow its essential nature with four females.
每只老鼠都可以与四只雌性老鼠自由交配。
Only those rats given the saline sired offspring.
只有那些注射了生理盐水的老鼠能繁殖后代。
The real test, as the team reports in acs Nano, a nanotechnology journal, came next: half the rats given the new treatment were exposed to a blast of ultrasound.
接下来，研究小组在纳米技术期刊《acs Nano》上发表了真正的测试：接受新实验的老鼠中有一半暴露在超声波冲击波下。
That evidently dissolved the hydrogel in the creatures’ pipes: they could again reproduce, while those not thusly blasted stayed sterile.
很明显，在超声波下，老鼠体内的水凝胶溶解了，它们可以再次繁殖，而那些没有暴露在超声波下的老鼠依然不能生育。
What works in rats, alas, does not always work in humans, so further trials will be needed.
可惜的是，在老鼠身上有效的方法在人类身上并不总是有效，因此还需要进一步的试验。
But Dr Xu is hopeful that these findings represent a sound idea for a reversible contraceptive--with fewer sticking points.
但徐博士希望这些发现代表了可逆避孕的一个可靠想法--减少结扎。
