Darbepoetin alfa as primary prophylaxis of anaemia in breast cancer patients treated preoperatively with Docetaxel, Doxorubicin, Cyclophosphamide : meeting abstract

Meeting Abstract : 27. Deutscher Krebskongress. Berlin, 22.-26.03.2006. Docetaxel, Adriamycin, Cyclophosphamide (TAC) is considered today as one treatment option for patients with node-positive primary breast cancer. However, treatment is associated with anaemia grade 1-4 (2-4) in up to 95% (36%) of patients. We prospectively investigated the use of a primary prophylaxis with Darbepoetin alfa once every 3 weeks in 35 patients receiving six to eight cycles of TAC as neoadjuvant treatment for breast cancer. Darbepoetin treatment started on day 1 of a TAC cycle if haemoglobin (Hb) was ≤ 14.0 g/dl. Dosage was adapted to 9 µg/kg if Hb was ≤ 13.0 g/dl on day 21 of the previous cycle, to 4.5 µg/kg if Hb was between 13.0 and 14.0 g/dl and was discontinued if Hb increased to ≥ 14 g/dl. The primary aim was to prevent Hb levels ≤ 12 g/dl before surgery. During 112 (50.2%) and 93 (41.7%) of 223 cycles, 4.5 µg/kg and 9 µg/kg Darbepoetin were given, respectively. Dosage was decreased from 9 to 4.5 µg/kg in 21 (60%) patients and 28 (12.4%) cycles. Treatment was discontinued due to Hb > 14.0 g/dl in 12 (34.3%) patients and 13 (5.4%) cycles. Hb level on day 21 of the last cycle was ≤ 12.0 g/dl in 4 (11.4%) patients. Eighteen (51.4%) patients during 36 (16.1%) cycles showed Hb levels ≤ 12 g/dl throughout treatment. No NCI-CTC grade 2 to 4 anaemia was observed. Symptoms of fatigue (FACT-AN) decreased slightly throughout treatment. Anaemia during TAC chemotherapy can be avoided by a single injection of Darbepoetin alfa every 3 weeks

Rationality of Darmon Points Over Genus Fields of Nonmaximal Orders

Stark-Heegner points, also known as Darmon points, were introduced by H. Darmon in [11], as certain local points on rational elliptic curves, conjecturally defined over abelian extensions of real quadratic fields. The rationality conjecture for these points is only known in the unramified case, namely, when these points are specializations of global points defined over the strict Hilbert class field H+ F of the real quadratic field F and twisted by (unramified) quadratic characters of Gal(H+ F /F). We extend these results to the situation of ramified quadratic characters; we show that Darmon points of conductor c ≥ 1 twisted by quadratic characters of G+ c =Gal(H+ c /F), where H+ c is the strict ring class field of F of conductor c, come from rational points on the elliptic curve defined over H+ c

The emergence of a self-catalysing structure in abstract origin-of-life models

We formalize a class of abstract and simple biochemical models that have been proposed for understanding the origin of life. We then analyse conditions under which 'life-like' substructures will tend to arise in such models

A Convenient Route to Monoalkyl-Substituted Phosphanylboranes (HRP–BH2–NMe3): Prospective Precursors to Poly[(alkylphosphino)boranes]

A simple method to access borylphosphonium iodides [RH2P-BH2 center dot NMe3]I (1a: R = Me; 1b: R = Et; 1c: R = nPr) by the addition of iodoalkanes to PH2-BH2 center dot NMe3 was developed. Complexes 1a-c were characterized by multinuclear NMR spectroscopy, and 1a and 1b additionally by single-crystal X-ray diffraction. It was possible to synthesize the Lewis-base-stabilized organosubstituted phosphanylborane MePH-BH2 center dot NMe3 (2) from [MePH2-BH2 center dot NMe3] I (1a). Thermolysis of 2 generated a soluble, low-molecular-mass poly(alkylphosphinoborane)consisting of at least 40 repeat units, as identified by ESI-MS. These results are promising for the future preparation of a wide range of Lewis-base-stabilized phosphanylboranes, which are of interest as precursors to poly[(alkylphosphino)boranes] and are otherwise difficult to access by conventional metal-catalyzed methods

The Coordination Chemistry of the Phosphanylborane (C6H5)2PBH2·N(CH3)3 towards Copper(I) salts

The reactions of the phosphinoborane Ph2PBH2 center dot NMe3 with Cu-(I) halides [CuCl, CuBr, CuI] and [Cu(CH3CN)(4)BF4], respectively, were studied. Depending on the ratio of the reactants used, the former reaction allowed for the synthesis of eight neutral coordination compounds with the general formula [CunXn(Ph2PBH2 center dot NMe3)(m)] (X = Cl, Br, I; n = 1, 2, 4, 5; m = 2, 4) (4-11). The latter reaction, however, led to the formation of the homoleptic complex [Cu(Ph2PBH2 center dot NMe3)(3)][BF4] (13). The structures of the products 4-11 and 13 were compared to related complexes possessing the well-known Ph3P ligand. All compounds were characterized by single crystal X-ray structure analysis, multinuclear NMR spectroscopy, IR spectroscopy and mass spectrometry

Carrier Recombination in Highly Uniform and Phase-Pure GaAs/(Al,Ga)As Core/Shell Nanowire Arrays on Si(111): Mott Transition and Internal Quantum Efficiency

GaAs-based nanowires are among the most promising candidates for realizing a monolithical integration of III-V optoelectronics on the Si platform. To realize their full potential for applications as light absorbers and emitters, it is crucial to understand their interaction with light governing the absorption and extraction efficiency, as well as the carrier recombination dynamics determining the radiative efficiency. Here, we study the spontaneous emission of zincblende GaAs/(Al,Ga)As core/shell nanowire arrays by $\mu$-photoluminescence spectroscopy. These ordered arrays are synthesized on patterned Si(111) substrates using molecular beam epitaxy, and exhibit an exceptionally low degree of polytypism for interwire separations exceeding a critical value. We record emission spectra over more than five orders of excitation density for both steady-state and pulsed excitation to identify the nature of the recombination channels. An abrupt Mott transition from excitonic to electron-hole-plasma recombination is observed, and the corresponding Mott density is derived. Combining these experiments with simulations and additional direct measurements of the external quantum efficiency using a perfect diffuse reflector as reference, we are able to extract the internal quantum efficiency as a function of carrier density and temperature as well as the extraction efficiency of the nanowire array. The results vividly document the high potential of GaAs/(Al,Ga)As core/shell nanowires for efficient light emitters integrated on the Si platform. Furthermore, the methodology established in this work can be applied to nanowires of any other materials system of interest for optoelectronic applications

Coordination of Pnictogenylboranes Towards Tl(I) Salts and a Tl‐ Mediated P−P Coupling

The coordination chemistry of only Lewis-base (LB)-stabilized pnictogenylboranes EH2BH2⋅NMe3 (E=P, As) towards Tl(I) salts has been studied. The reaction of Tl[BArCl] (BArCl=[B(3,5-C6H3Cl2)4]−) with the corresponding pnictogenylborane results in the formation of [Tl(EH2BH2⋅NMe3)][BArCl] (1 a: E=P; 1 b: E=As). Whereas the Tl ion in 1 a/b is monocoordinated, the exchange of the weakly coordinating anion (WCA) in the Tl(I) salt leads to the formation of a trigonal pyramidal coordination mode at the Tl atom by coordination of three equivalents of EH2BH2 ⋅ NMe3 in [Tl(EH2BH2 ⋅ NMe3)3][WCA] (2 a: E=P, WCA=TEFCl; 2 b: E=As, WCA=TEF) (TEF=[Al{OC(CF3)3}4]−, TEFCl=[Al{(OC(CF3)2(CCl3)}4]−). Furthermore, by using two equivalents of PH2BH2⋅NMe3, a Tl(I)-mediated P−P coupling takes place in CH2Cl2 as solvent resulting in [Me3N⋅BH2PH2PHBH2⋅NMe3][WCA] (WCA=TEF, 3 a; BArCl, 3 b; TEFCl, 3 c). In contrast, for the arsenic derivatives 1 b and 2 b, no coupling reaction is observed. The underlying chemical processes are elucidated by quantum chemical computations