Zhan et al. reported a fused ring electron acceptor (FREA) ITIC with an acceptordonor-acceptor (A-D-A) type structure. [1] Subsequently, numerous FREAs are developed by researchers, which largely promoted the photovoltaic performance of OSCs. Recently, Zou et al. developed a series of A-DA′D-A type FREAs (Y6 series). Up to now, the highest power conversion efficiency (PCE) of OSCs based on FREAs has reached 18%, demonstrating the bright future for practical application. [2][3][4][5][6][7][8][9] Although FREAs can achieve high efficiency, they are expensive and their syntheses are complicated, which usually includes low-yield ring-closure reactions. For the commercialization of OSCs, it is highly desired to develop highperformance and low-cost nonfullerene acceptors. Therefore, we want to develop simple nonfused ring electron acceptors (NFREAs) to replace the high-cost FREAs. In 2017, we first postulated and proved that intramolecular noncovalent interactions could be used to partially replace chemical bonds to synthesize NFREAs. [10] Since then, small fused ring building blocks such as indacenodithiophene (IDT), [11][12][13][14] cyclopentadithiophene (CPDT), [15][16][17][18][19][20][21][22][23][24] etc., were often used for the construction of NFREAs. Later, researchers also developed fully nonfused ring electron acceptors. [25][26][27] However, the photovoltaic performance of the solar cells based on NFREAs is still far behind the FREAs.Typical FREAs consist of a fused ring core, side chains, and two electron-withdrawing terminal groups. [28][29][30][31] The planar fused ring core is beneficial for the electron delocalization. The side chain can increase the solubility and affect the molecular stacking of acceptors. The electron-withdrawing terminal group such as 3-(1,1-dicyanomethylene)-5,6-difluoro-1-indanone can induce a strong intramolecular charge transfer (ICT) effect in the acceptor molecule, which can remarkably broaden the absorption, lower the energy levels (especially the lowest unoccupied molecular orbital (LUMO)), and enhance the molecular stacking. [32][33][34] Besides these basic characteristics, recent reports begin to focus on molecular stacking model. There is growing evidence that high-performance FREAs possess a 3D network packing structure, being in favor of facilitating multiple charge transport, achieving small exciton binding energy, and reducing energy loss in OSCs. [5,[35][36][37][38][39] Unlike rigid FREAs, the molecular Three nonfused ring electron acceptors (NFREAs; 2Th-2F, BTh-Th-2F, and 2BTh-2F) with thieno[3,2-b]thiophene bearing two bis(4-butylphenyl)amino substituents as the core, 3-octylthiophene or 3-octylthieno[3,2-b]thiophene as the spacer, and 3-(1,1-dicyanomethylene)-5,6-difluoro-1-indanone as the terminal group are designed and synthesized. The molar extinction coefficient of acceptors and the electron mobility of blend films gradually increase with increasing π-conjugation length. Moreover, 2BTh-2F displays a planar molecular conformation assisted by S•••N and S•••O intr...

During development, many neuronal populations undergo a process of normal, programmed cell death, or apoptosis. Trophic factors regulate this process, but the mechanism by which they suppress apoptosis remains unclear. In the immune system, recent studies have implicated the protooncogene bcl-2 in the lymphocyte survival response to growth factors. To determine whether a similar survival pathway exists in a neuroendocrine cell type, we have expressed bcl-2 in the rat pheochromocytoma PC12 cell line and found that it abrogates the requirement for stimulation by growth factors to survive. bcl-2 expression also substantially delays the onset of injury by the calcium ionophore A23187.

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Staging of two laser-driven, relativistic electron accelerators has been demonstrated for the first time in a proof-of-principle experiment, whereby two distinct and serial laser accelerators acted on an electron beam in a coherently cumulative manner. Output from a CO2 laser was split into two beams to drive two inverse free electron lasers (IFEL) separated by 2.3 m. The first IFEL served to bunch the electrons into approximately 3 fs microbunches, which were rephased with the laser wave in the second IFEL. This represents a crucial step towards the development of practical laser-driven electron accelerators.

7.6 3 10 6 x-ray photons per 3.5 ps pulse are detected within a 1.8-2.3 Å spectral window during a proof-of-principle laser synchrotron source experiment. A 600 MW CO 2 laser interacted in a head-on collision with a 60 MeV, 140 A, 3.5 ps electron beam. Both beams were focused to a s 32 mm spot. Our next plan is to demonstrate 10 10 x-ray photons per pulse using a CO 2 laser of ϳ1 TW peak power.

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Laser scanning technology is one of the most integral parts of today's scientific research, manufacturing, defense, and biomedicine. In many applications, high-speed scanning capability is essential for scanning a large area in a short time and multi-dimensional sensing of moving objects and dynamical processes with fine temporal resolution. Unfortunately, conventional laser scanners are often too slow, resulting in limited precision and utility. Here we present a new type of laser scanner that offers ∼1,000 times higher scan rates than conventional state-of-the-art scanners. This method employs spatial dispersion of temporally stretched broadband optical pulses onto the target, enabling inertia-free laser scans at unprecedented scan rates of nearly 100 MHz at 800 nm. To show our scanner's broad utility, we use it to demonstrate unique and previously difficult-to-achieve capabilities in imaging, surface vibrometry, and flow cytometry at a record 2D raster scan rate of more than 100 kHz with 27,000 resolvable points.

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