國際科技信息

歐盟先進(jìn)硅材料研究取得重大突破

歐盟第七研發(fā)框架計(jì)劃（FP7）信息通訊技術(shù)（ICT）主題資助850萬歐元的研發(fā)項(xiàng)目HELIOS“互補(bǔ)金屬氧化物半導(dǎo)體的光電子功能集成”,在近期的研究過程中取得了重大的創(chuàng)造性突破。

由法國原子能委員會電子與信息技術(shù)實(shí)驗(yàn)室（CEALeti）科研人員領(lǐng)導(dǎo)的，歐盟成員國法國、英國和比利時(shí)科技人員共同參與的研究團(tuán)隊(duì)，首次研發(fā)出世界上第一個(gè)硅基材料可調(diào)諧發(fā)射器，從而邁出了整體集成硅基發(fā)射/接收器（Tranceivers）的關(guān)鍵一步。研究結(jié)果在近日美國洛杉磯舉行的“2012光纖通訊大會”上，正式對外宣布。

硅光子學(xué)是一項(xiàng)功能強(qiáng)大的新興技術(shù)學(xué)科，硅光子學(xué)具備大規(guī)模制造互補(bǔ)金屬氧化物半導(dǎo)體（CMOSs）光子器件的潛力，但光子器件制作目前因技術(shù)的缺乏而造價(jià)昂貴。此外，硅光子學(xué)的另一項(xiàng)重要障礙，是作為CMOSs基本材料的硅基光子源，制約了硅光子學(xué)的進(jìn)一步發(fā)展。

研究團(tuán)隊(duì)的科研人員首先研制出一臺新型調(diào)節(jié)器，利用該調(diào)節(jié)器制作出單一波長的可調(diào)諧激光器，20攝氏度溫度下的臨界電流20mA，調(diào)諧幅度45nm，超過調(diào)諧范圍的側(cè)模壓抑率（Side Mode Suppression Ratio）大于40dB。

然后，科研人員將主動(dòng)發(fā)光源必須的CMOS III-V型材料嵌入到一個(gè)硅晶片上，進(jìn)行同時(shí)加工處理，如此，兩項(xiàng)加工一次性處理完成。盡管加工過程中仍然采用傳統(tǒng)的CMOS加工工藝，但新方法可以同時(shí)直接將主動(dòng)發(fā)光源嵌入到硅晶片上。

科研人員在硅基材料上集成可調(diào)諧激光器、調(diào)節(jié)器和被動(dòng)波導(dǎo)的能力，開辟了進(jìn)一步開發(fā)硅基發(fā)射/接收器的有效途徑。

從而滿足各方面的需求：大城市群網(wǎng)絡(luò)、互聯(lián)網(wǎng)接入、服務(wù)器、數(shù)據(jù)中心、高性能計(jì)算機(jī)、以及光互聯(lián)，實(shí)現(xiàn)光通訊的徹底變革。

HELIOS makes silicon breakthrough

Researchers in Europe have succeeded in presenting an integrated tuneable transmitter on silicon — the first time this has ever happened. This results are an outcome of the HELIOS ('Photonics electronics functional integration on complementary metal oxidesemiconductor, CMOS') project, which is backed under the 'Information and communication technologies' (ICT) Theme of the EU's Seventh Framework Programme (FP7) to the tune of EUR 8.5 million. The team presented the results at the recent Optical Fiber Communication conference in Los Angeles, United States.

Experts from the Electronics and Information Technology Laboratory of the French Atomic Energy Commission (CEA-Leti) and III-V lab, a joint lab of Alcatel-Lucent Bell Labs France, in cooperation with Thales Research and Technology in the United Kingdom, say the tuneable laser source integrated on silicon is a groundbreaking achievement in efforts to secure fully integrated transceivers. Researchers at Ghent University and the Interuniversity Microelectronics Centre (IMEC) in Belgium, and the University of Surrey in the United Kingdom, who designed the modulator, supported the research.

The group from CEA-Letiand III-V lab also demonstrated single wavelength tuneable lasers, with a 21 mA threshold at 20o Celsius, a 45 nm tuning range and a side mode suppression ratio larger than 40 dB over the tuning range.

The researchers say silicon photonics is a powerful technology. Silicon photonics have the potential to bring the largescale manufacturing of CMOS to photonic devices that are not cheap because the technology is missing. Another challenge to silicon photonics is the lack of optical sources on silicon, the base material on CMOSs, according to the researchers.

'We can overcome this problem by bonding III-V material, necessary for active light sources, onto a silicon wafer and then co-processing the two, thus accomplishing two things at once,' says Martin Zirngibl, Bell Labs Physical Technologies Research leader. 'Traditional CMOS processing is still used in the process, while at the same time we now can integrate active light sources directly onto silicon.'

Commenting on the results, CEA-LetiFrance Photonics Program Manager, Laurent Fulbert, says: 'We are proud to jointly present with III-V lab the results of the integrated silicon photonics transmitier and the tuneable laser. The ability to integrate a tuneable laser, a modulator and passive waveguides on silicon paves the way of further developments on integrated transceivers that can address several application needs in metropolitan and access networks, servers, data centres, high-performance computers as well as optical interconnects at rack-level and board-level. We are pleased to bring our contribution to these state-of-the-art results which can truly revolutionise optical communications.'

瑞士太陽能飛機(jī)準(zhǔn)備首次洲際飛行

瑞士探險(xiǎn)家貝特朗·皮卡爾24日在瑞士城市帕耶訥說，他和同伴駕駛的大型太陽能飛機(jī)“太陽驅(qū)動(dòng)”號預(yù)計(jì)于今年5月從帕耶訥飛往北非國家摩洛哥，實(shí)現(xiàn)首次洲際飛行，目前他們正在進(jìn)行最后階段的準(zhǔn)備。

發(fā)起這一項(xiàng)目的皮卡爾當(dāng)天在記者會上說，這架太陽能飛機(jī)將在天氣狀況良好時(shí)擇機(jī)從帕耶訥機(jī)場起飛，此后將在西班牙首都馬德里和摩洛哥首都拉巴特各停留一次，在總共飛行2500公里后抵達(dá)摩洛哥中部城市瓦爾扎扎特，此次飛行將完全依靠太陽能。

飛行指揮雷蒙·克萊爾說，這將是“太陽驅(qū)動(dòng)”號迄今航程最遠(yuǎn)的一次飛行，全程將持續(xù)48小時(shí)，飛機(jī)將由皮卡爾和另一位項(xiàng)目發(fā)起人安德烈·博爾施貝格輪流駕駛，這種“換崗”將在飛機(jī)中途短暫著陸后實(shí)施。在飛行期間駕駛員不休息，僅以三明治和能量食品充饑。

克萊爾說，“太陽驅(qū)動(dòng)”號將飛越比利牛斯山和地中海，天氣因素是最大挑戰(zhàn)。這架飛機(jī)的機(jī)體較輕，對風(fēng)、云、雨和大氣湍流敏感。此外，“太陽驅(qū)動(dòng)”號還要與途經(jīng)的法國、西班牙和摩洛哥等國空中管理部門進(jìn)行有效溝通，確保不會干擾民航和軍機(jī)飛行。

博爾施貝格說，這次長途飛行是“太陽驅(qū)動(dòng)”號2014年環(huán)球飛行前的演練，主要目的是協(xié)調(diào)機(jī)組人員與各國機(jī)場的合作，檢驗(yàn)飛機(jī)的維護(hù)保養(yǎng)措施等。

依據(jù)設(shè)計(jì)，“太陽驅(qū)動(dòng)”號是能晝夜飛行的太陽能飛機(jī)，由超輕碳纖維材料制成，翼展達(dá)63.4米，與空客A340型飛機(jī)翼展相仿，其重量只有1600公斤，相當(dāng)于一輛普通小汽車。

這架飛機(jī)的機(jī)翼上裝有約1.2萬塊太陽能電池板，為4臺電動(dòng)機(jī)供電，白天飛行時(shí)可將多余的太陽能電力儲存到蓄電池中供夜間使用，實(shí)現(xiàn)無燃油晝夜飛行。

“太陽驅(qū)動(dòng)”號于2010年7月完成首次24小時(shí)不間斷飛行，去年5月首次完成瑞士至比利時(shí)跨國飛行。

A cross-continent flight in May or June will change aviation history

The world's largest solarpowered plane, Swiss-made Solar Impulse, will take its f rst-ever crosscontinent f ight in May or June.

The plane, co-piloted by Bertrand Piccard and Andre Borschberg, will attempt for the first time to fly more than 2,500 km, taking of in Payerne in western Switzerland, crossing the Pyrenees and the Mediterranean without using fuel, and landing in Morocco.

The exact date for taking off will be decided according to weather condition, said Andre Borschberg, co-founder and CEO of Solar Impulse that made the aircraft.Bertrand Piccard and Borschberg will take turns to f y the aircration its 48-hour journey, with a scheduled stopover near Madrid to change pilots, Xinhua reported.

This long-duration flight will serve as a dress rehearsal for the round-the-world flight in 2014, and will allow the team to gather experience in cooperating with international airports, integrating the prototype into regular air traffic patterns, and managing the logistics of maintenance, said Borschberg.Solar Impulse, the f rst aircraft that can fly day and night without fuel or polluting emissions, has a wingspan of 63.4 meters, as wide as an Airbus A340, and weighs only 1,600 kg. It has 12,000 solar cells mounted on the wings, which provide momentum for its four electric motors.

The plane took its first international f ight from Switzerland to Brussels May 13, 2011, and marked its second international f ight to Paris in June last year.

According to Solar Impulse, the solar aircraft “can fly day and night without fuel or polluting emissions.”

A press release issued by the company stated: “This revolutionary carbon f bre aircrati, that has the wingspan of an Airbus A340 (63.4m) and the weight of an average family car (1,600kg), is the result of seven intense years of work, calculations, simulations and tests by a team of 70 people and 80 partners.

“A plane this light and of this size has never been built before. The 12,000 solar cells built into the wing provide four 10HP electric motors with renewable energy.

“By day the solar cells recharge the 400kg lithium batteries which means the plane can f y at night.”

德研發(fā)“智能”輪胎可根據(jù)天氣環(huán)境改變外形

對一些汽車車主而言，挑選輪胎或許是一項(xiàng)令人糾結(jié)的抉擇，考慮剎車性能還是油耗、應(yīng)該如何在長途旅行中應(yīng)對天氣變化都是困擾車主的難題。

不過，德國研究人員正在研發(fā)一款“智能”輪胎，有望消除車主的煩惱。

德國萊比錫應(yīng)用科學(xué)大學(xué)學(xué)者德特勒夫·里默爾及其研究團(tuán)隊(duì)在今年的漢諾威工業(yè)博覽會上推出這款輪胎。依據(jù)構(gòu)想，它可以根據(jù)天氣、地形作出“改變”。

法新社23日援引里默爾的話報(bào)道：“今天，選擇輪胎往往要作出讓步，兼顧油耗和剎車性能，駕駛員還需要考慮各種天氣狀況?！?/p>

不過，里默爾說，他們研制的“智能”輪胎具備“適應(yīng)性”，裝有電子傳感器，可以辨認(rèn)各種地形，測定路面是干燥、積水還是積雪，從而依據(jù)傳感器數(shù)據(jù)在車輛行進(jìn)間改變外形。

“這意味著，你的車總是安裝最好的輪胎，噪音和油耗都可以自動(dòng)優(yōu)化，”里默爾說，“駕駛員不用再考慮如何讓輪胎適應(yīng)（環(huán)境），輪胎自己會‘考慮’。”

他說，這款輪胎仍處在研發(fā)階段，距離推出成品尚有時(shí)日，主要原因是研究人員還沒有找到可用于制造輪胎可變化部位的合適原料。

German scientists unveil 'intelligent' tyre for all weather

Are you fed up of having to change your summer tyres for winter tyres at the first sign of snow? Or of being caught out on a long car journey by sudden changes in the weather?

That may soon be a thing of the past, according to a group of researchers at Leipzig university, who are developing the world's first-ever "intelligent" tyre which automatically adapts itself to the prevailing weather conditions even while you are driving.

A team of researchers headed by Detlef Riemer at the University of Applied Sciences in Leipzig unveiled the "adaptive tyre" at this year's Hanover Fair, the world's biggest industrial fair taking place in the north German city this week.

"Today's choice of tyres are always a compromise between the ability to brake and petrol consumption," Riemer said.

"The car driver has to take into consideration every sort of weather condition and you can't change tyres while you're driving."

But Riemer's "adaptive tyre" is equipped with electronic sensors which recognise different sorts of terrain -- whether motorway or untarmacked roads -- and whether it's dry, raining or snowing.

And accordingly, the tyres' prof les are automatically raised or widened accordingly, even when the car is in motion.

"That means your car is always equipped with the best possible tyre and noise and petrol consumption are automatically optimised, too," Riemer enthused.

"The driver no longer has to think about adapting their tyres. The tyre itself 'thinks' too."

The tyre is still a long way from a finished product and research is still ongoing, notably on the materials that can be used for the moveable parts of the tyre's prof les.

"But we've patented it already, just in case," Riemer said.

德國研究人員發(fā)現(xiàn)癌細(xì)胞的“阿基里斯之踵”

德國維爾茨堡大學(xué)與亥姆霍茲大研究中心聯(lián)合會傳染病研究中心的研究人員合作研究，發(fā)現(xiàn)了癌細(xì)胞的“阿基里斯之踵”，其相關(guān)研究成果已在《自然》雜志上發(fā)布。

新的癌癥治療方法的基本機(jī)制是：在關(guān)閉癌細(xì)胞內(nèi)部的能量監(jiān)控機(jī)制后，癌細(xì)胞將無視內(nèi)部的新陳代謝需要繼續(xù)分裂繁殖，最終因缺乏足夠能量供應(yīng)而死亡。制藥企業(yè)已經(jīng)對該技術(shù)方案表示出極大興趣。

根據(jù)德國癌癥援助協(xié)會發(fā)布的統(tǒng)計(jì)數(shù)字：德國每年新增約49萬癌癥患者，而同期約有21.8人死于癌癥。專家預(yù)測到2050年該數(shù)字還將會提高約30%。目前，對于癌癥常見的治療方式是放療和化療，通過放療和化療來阻止癌細(xì)胞繼續(xù)生長。此次，德國維爾茨堡大學(xué)的研究人員卻采取了全新研究思路：讓癌細(xì)胞無節(jié)制生長直至死亡，而其基礎(chǔ)理論就是簡單的后勤供應(yīng)問題。

與其他身體細(xì)胞一樣，癌細(xì)胞存活生長就要從營養(yǎng)物質(zhì)中不斷獲取能量。一方面用于細(xì)胞自身生成發(fā)育，另一方面用于細(xì)胞分裂繁殖。此外，還要保障細(xì)胞內(nèi)部的基本新陳代謝。研究人員在研究關(guān)閉特定的酶對癌癥細(xì)胞反應(yīng)過程中，發(fā)現(xiàn)了具有資源管理功能的一種“監(jiān)控分子酶”。當(dāng)有足夠的能量ATP情況下，癌細(xì)胞自身生長發(fā)育和分裂繁殖過程是平衡的。當(dāng)能量ATP稀缺情況下，監(jiān)控分子酶將通過調(diào)節(jié)機(jī)制首先確保癌細(xì)胞自身基本新陳代謝的能量需求，從而實(shí)現(xiàn)自我保護(hù)的目標(biāo)。為此，在能量稀缺情況下，癌細(xì)胞如果無法從監(jiān)控分子酶獲取能量平衡反饋信息時(shí)，它們將繼續(xù)浪費(fèi)大量能量資源進(jìn)行分裂繁殖活動(dòng)。最終會因?yàn)槟芰抗?yīng)不足而自我死亡。

研究人員把這種監(jiān)控分子酶稱為Ark5酶，這種酶就好比是癌細(xì)胞的“阿基里斯之踵”，可以作為治療癌癥的新藥物。研究人員已成功在實(shí)驗(yàn)鼠體內(nèi)進(jìn)行了測試，證實(shí)其可以有效抑制和縮小實(shí)驗(yàn)鼠體內(nèi)的肝腫瘤。目前實(shí)驗(yàn)顯示該方法在實(shí)驗(yàn)動(dòng)物體內(nèi)可以有效對抗結(jié)腸癌和肝癌細(xì)胞，對其它癌細(xì)胞是否有效還有待研究。此外，研究人員還驚奇發(fā)現(xiàn)，監(jiān)控分子酶失去活性對于普通健康細(xì)胞沒有任何影響，其具體原因還有待進(jìn)一步研究。當(dāng)然，研究人員和制藥企業(yè)更看重的是其未來用于治療癌癥的巨大潛力。

An Indirect Way to Get at the Elusive MYC Cancer Target

Scientists at the Theodor Boveri Institute at the University of Würzburg in Germany have potentially found a way to indirectly target the MYC oncogene—an elusive cancer therapy target. Martin Eilers and colleagues discovered that cancer cells with upregulated levels of MYC are dependent on AMPK-related kinase 5 (ARK5) to stay alive. ARK5, it turns out, is necessary for these cells to maintain metabolic homeostasis. The study, published last month in Nature, shows that inhibition of ARK5 causes these MYC-dependent cells to die, partly due to depriving them of cellular ATP, leading to apoptosis.

Malignant B-cell lymphocytes seen in Burkitt lymphoma, H&E stain. The MYC gene was discovered in the 1970s in Burkitt lymphoma patients.The research validates the connection between MYC and ARK5 expression seen in several primary solid tumor samples, including liver and pancreatic carcinomas.

ARK5 may be a potential drug target for tumors that overexpress MYC, according to the authors. This would be a way to get around the problem of targeting MYC itself. In general, the authors highlight that targeting the “oncogene-altered energy metabolism” pathways in tumor cells may be a new way to isolate cancer therapy targets.

The MYC gene was discovered in the 1970s in Burkitt lymphoma patients. MYC encodes a transcription factor that is important for regulating many pathways involved in cell growth, cell cycle progression, and apoptosis. It is an oncogene that is found deregulated in many cancer types. MYC does not have good target-binding sites and is far away from the cell membrane, two reasons that help explain why no good drug candidates have been able to target the protein.

Partial karyotype showing translocations involving chromosome 8 and chromosomes 2, 14, and 22. The cellular oncogenes MYC, FOS, and SIS have been mapped to the chromosomal sites indicated. H, k, and x indicate the location of genes for the heavy and light chain immunoglobulins“MYC is such an elusive target since it is a transcription factor with large protein-protein interaction surfaces,” explains Eilers.

The Study and Results

The researchers identified ARK5 and a related kinase, AMPK in a short-interfering RNA screen using a human cancer cell line overexpressing MYC. The purpose of the screen was to identify factors that facilitate the survival of MYC overexpressing cancer cells. When ARK5 was depleted, the MYC-expressing cells showed signs of apoptosis. The study found that the levels of MYC protein necessary for dependence on ARK5 are much higher than the MYC levels that are required to induce proliferation. Induced expression of apoptosisinhibiting factor did not alleviate the dependence of the cells on ARK5.

The experiments in the published paper show that ARK5 helps cancer cells survive in a metabolically stressful environment induced by MYC hyperactivity.

In an MYC-overexpressing liver cancer mouse model, the researchers show that ARK5 is important. "ARK5 is necessary to maintain sufficient respiratory capacity in MYC-transformed cells,”state the authors. Depletion of ARK5 caused cells to undergo the cell cycle in a much slower manner, showing that ARK5 facilitates cell growth. This demonstrates the synthetic lethality of deregulated MYC expression and inhibition of ARK5.

The study also showed that the synthetic lethality of high MYC expression and loss of ARK5 could be rescued by addition of rapamycin. Rapamycin is a drug that inhibits the mammalian target of rapamycin (mTOR) pathway that is involved in cell survival and proliferation. This shows, explained Eilers, that deregulation of mTOR is the “key mode” of cell death as mTOR inhibitors can protect cell viability in MYC-overexpressing cells that are depleted of ARK5.

To test the potential therapeutic efficacy of ARK5 depletion, the study researchers transplanted mouse liver cancer cells that express MYC—depletion of ARK5 caused cell death, and rapamycin restored ATP levels and sustained the ARK5-depleted culture. The transplanted cells resulted in 8 of 8 carcinomas in mice.

“We propose that negative regulators of the mTOR pathway, like ARK5, may be good targets for therapy of MYC-expressing tumors,” says Eilers.

Next Steps

“The key question, in my view, is whether the metabolic crisis that we observe in tissue culture when we deplete ARK5 in MYC-expressing cells, is also seen in vivo in human tumor cells,” says Eilers. The evidence for the metabolic imbalance created by removing ARK5 has so far only been shown in engineered mouse cells in vivo.

Eilers says that there are currently no available inhibitors of ARK5 but that he believes it is a good idea to develop them to test them in MYC-expressing tumors. He adds that recent work from the laboratory of James Bradner, MD at the Dana-Farber Cancer Institute in Boston, on compounds that inhibit a protein called BRD4 is “an exciting approach.” BRD4 functions to activate MYC.

“Targeting MYC, after all these years, is becoming a rational approach for developing tumor therapies,” says Eilers.

干細(xì)胞培育毛囊技術(shù)有望治療禿頭癥

日本研究人員在新一期英國《自然!通信》雜志上發(fā)表報(bào)告說，他們利用成年實(shí)驗(yàn)鼠干細(xì)胞和人類干細(xì)胞分別培育出毛囊，并移植到?jīng)]毛發(fā)的實(shí)驗(yàn)鼠皮膚上，都成功讓它長出毛發(fā)，未來有望將這一技術(shù)用于治療禿頭癥。

東京理科大學(xué)教授!孝領(lǐng)導(dǎo)的研究小組從實(shí)驗(yàn)鼠皮膚上獲取了兩種干細(xì)胞，并在實(shí)驗(yàn)室中將它們培育成毛囊，然后將這種人工培育的毛囊移植到本身沒有毛發(fā)的實(shí)驗(yàn)鼠皮膚上，結(jié)果后者成功長出了毛發(fā)。分析顯示，移植的毛囊與周圍的皮膚和神經(jīng)等組織融合良好，在毛發(fā)脫落后還能繼續(xù)長出新的毛發(fā)。

據(jù)研究人員介紹，他們還從一名人類禿頭癥患者的頭皮上提取了相關(guān)組織，并按同樣方法培育出毛囊，移植到實(shí)驗(yàn)鼠皮膚上后也能長出毛發(fā)。

這項(xiàng)成果為禿頭癥患者帶來新希望。如果進(jìn)一步臨床實(shí)驗(yàn)取得成功，禿頭癥患者將來也許只需提供一些頭皮細(xì)胞，就能重新長出頭發(fā)。研究人員說，將力爭10年內(nèi)把這項(xiàng)技術(shù)轉(zhuǎn)化為可臨床應(yīng)用的新療法。

除了頭發(fā)再生外，研究人員還說，可通過在人工培育毛囊時(shí)改變其中的細(xì)胞構(gòu)成，從而控制毛囊移植后所長出毛發(fā)的密度和顏色。也就是說，一名白發(fā)稀疏的老者將來或可利用這項(xiàng)技術(shù)獲得滿頭濃密的黑發(fā)。

Attention, balding men. Japanese scientists regrow human hair in mice

A tiny black tutiof hair on a bald mouse’s head is evidence that stem-cell research in Japan could reverse hair loss in humans.

“The bioengineered hair follicle develops the correct structures (and) restored hair cycles,” Dr. Takashi Tsuji reports in the current issue of Nature Communications.

The strands of hair implanted themselves below the skin of the mice, showing it was not only possible to restore the hair follicle, but also to root it in the scalp, the study said.

Tsuji and his organregeneration team at Tokyo University Science have managed to “significantly advance the technological development of bioengineered hair follicle regenerative therapy.”

Restoring the nervous system is a critical issue in organregeneration work, Tsuji said. The study suggests that transplanting a“bioengineered hair follicle germ”can revive the muscles and nerve f bres associated with hair growth.

Painstaking research began with the bioengineering of various types of hair-follicle germs, which were grafted onto bald mice. The germs carried tiny nylon guides to nudge the growing hairs in the right direction.

Once that proved successful, the team moved on to bioengineering human hair-follicle germs and transplanting them in mice.

The human hairs grew in 21 days with the correct shatis, inner root sheaths and surrounding cells that normal human hair would, the study said.

Further tests proved the human hairs were, indeed, human.

The study is at the “proofof-concept” stage, meaning the theory works. Scientists will have to do more research to see if it can turn into therapy for baldness.