Modern telecommunications rely on the transmission and manipulation of optical signals. Optical amplification plays a vital part in this technology, as all components in a real telecommunications system produce some loss. The two main issues with present amplifiers, which rely on erbium ions in a glass matrix, are the difficulty in integration onto a single substrate and the need of high pump power densities to produce gain. Here we show a potential organic optical amplifier material that demonstrates population inversion when pumped from above using low-power visible light. This system is integrated into an organic light-emitting diode demonstrating that electrical pumping can be achieved. This opens the possibility of direct electrically driven optical amplifiers and optical circuits. Our results provide an alternative approach to producing low-cost integrated optics that is compatible with existing silicon photonics and a different route to an effective integrated optics technology.

Significance Inorganic phosphate (Pi) is an essential component of many biological molecules and thus is required by all life forms. However, soluble Pi is typically at low abundance in the environment. To compensate, microbes have evolved unique carbon–phosphorus-bond cleaving reactions to use organophosphonates as an alternative source of Pi. The marine-derived enzyme PhnZ utilizes a new oxidative mechanism for CP bond cleavage involving iron and molecular oxygen. The three-dimensional structure of PhnZ reveals unique active site features that contribute to catalysis of CP bond cleavage and substrate specificity, as well as an evolutionary link between phosphodiester bond hydrolysis and oxidative bond cleavage. This evolutionary link likely reflects the ancient origins of organophosphonates in the environment.

The sequential activities of PhnY, an α-ketoglutarate/Fe(II)-dependent dioxygenase, and PhnZ, a Fe(II)-dependent enzyme of the histidine-aspartate motif hydrolase family, cleave the carbon-phosphorus bond of the organophosphonate natural product 2-aminoethylphosphonic acid. PhnY adds a hydroxyl group to the α-carbon, yielding 2-amino-1-hydroxyethylphosphonic acid, which is oxidatively converted by PhnZ to inorganic phosphate and glycine. The PhnZ reaction represents a new enzyme mechanism for metabolic cleavage of a carbon-phosphorus bond.

The effect of CH and CD quenching on the luminescence lifetime of Er(3+) Nd(3+) and Yb(3+) in the Cs[Ln(HFA)(4)] system has been quantified, and we have shown that for Er(3+) ions the quenching is dominated by the nearest neighbor CH oscillators, whereas for Nd(3+) ions the roles of more distant CH oscillators and nearest neighbor CD oscillators are important.

The authors have quantified the quenching of the luminescence lifetime of Er 3+ ions in organic complexes due to the presence of CH vibrational oscillators as a function of their distance from the ion. They have shown that any hydrogen atoms within a sphere of at least 20 Å from an erbium ion will cause sufficient quenching to prohibit its use in telecommunications applications.

Dietary flavonoids have many healthpromoting actions, including anticancer activity via proteasome inhibition. Bortezomib is a dipeptide boronate proteasome inhibitor that has activity in the treatment of multiple myeloma but is not effective in chronic lymphocytic leukemia (CLL). Although CLL cells are sensitive in vitro to bortezomib-induced apoptosis when cultured in medium, the killing activity was blocked when cultured in 50% fresh autologous plasma. IntroductionBortezomib (Velcade) is a first-in-class proteasome inhibitor developed specifically for use as an antineoplastic agent. It is the most potent antineoplastic agent for the treatment of relapsed, refractory multiple myeloma. 1 A total of 73% of patients with myeloma responded to treatment with bortezomib combined with pegylated liposomal doxorubicin. 2 However, only 4 of 15 patients with acute leukemia showed a decrease in blast count. 3 The efficacy of bortezomib in chronic lymphocytic leukemia (CLL) appears to be related to IgV(H) and BCL-6 mutational status, 4 down-regulation of CD23, and inactivation of Notch 2. 5 However, we have previously shown that all primary CLL cells were sensitive to bortezomib in vitro. Proteasome inhibition increased Bax protein accumulation and Bax activation in CLL cells. Bortezomib also increased the sensitivity of CLL cells to TNF-related apoptosis-inducing ligand-induced apoptosis. 6 Although the effectiveness of bortezomib killing of CLL cells in vitro has also been reported by other groups, 4,5 it did not display substantial antitumor activity in patients with CLL. 7,8 The basis of this differential activity of bortezomib on CLL cells in vivo and in vitro is unknown. Autologous plasma is capable of maintaining survival of CLL cells in vitro and conferring resistance to chemo-radiotherapy, 9 and albumin in plasma plays an important role in this survival mechanism. 10 We sought to identify factors in the blood, which could prevent bortezomib-mediated killing of leukemic cells in the circulation.Quercetin is one of the most abundant flavonoids in the human diet and is a potent antioxidant. 11 Quercetin, abundant in human plasma, noncovalently binds to serum albumin. 12,13 It contributes to the prevention of human diseases by promoting relaxation of cardiovascular smooth muscle and protects low-density lipoprotein from oxidation. 14 Recent studies found that quercetin can induce apoptosis by inhibiting proteasome activation, 15 causing G 2 /M-phase arrest 16 and increasing p21 expression. 17 Other dietary flavonoids, such as myricetin, kaempferol, and apigenin, also have similar functions to quercetin with respect to proteasome inhibition and apoptosis induction. 15 In this study, we demonstrate that human plasma affects killing by bortezomib and that the dietary flavonoids, especially quercetin, inhibit bortezomib-induced apoptosis in malignant B-cell lines and primary CLL cells. This inhibitory activity of quercetin was associated with complex formation with bortezomib. However, in myeloma cell lines, quercetin al...

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It is expected that fluorinated organic erbium(III) complexes, of interest for optical applications at λ = 1.5 μm, have improved performance with respect to hydrogenated counterparts. However, the intrinsic radiative properties (including the absorption/emission line strengths) of organic Er 3+ complexes have not been systematically studied and compared up to date. This has precluded the observation of opto-structural correlations as well as a proper characterization of the infrared f-f transitions and thus a lack of meaningful figures for the optical efficiency of these materials at the 1.5 μm emission. We have performed a complete opto-structural correlation study of the oscillator strengths of the f-f transitions of hydrogenated and fluorinated organic erbium(III) complexes, including a Judd-Ofelt analysis. The Judd-Ofelt analysis on the crystals has allowed the study of the interdependence of the chemical nature, structure, and spectroscopic behavior. We observe clear trends that can help the design and understanding of these important infrared emitters for phosphor and opto-electronic applications.