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We report femtosecond Fe K-edge absorption (XAS) and nonresonant X-ray emission (XES) spectra of ferric cytochrome C (Cyt c) upon excitation of the haem (>300 nm) or mixed excitation of the haem and tryptophan (

The structure-function relationship is at the heart of biology, and major protein deformations are correlated to specific functions. For ferrous heme proteins, doming is associated with the respiratory function in hemoglobin and myoglobins. Cytochrome c (Cyt c) has evolved to become an important electron-transfer protein in humans. In its ferrous form, it undergoes ligand release and doming upon photoexcitation, but its ferric form does not release the distal ligand, while the return to the ground state has been attributed to thermal relaxation. Here, by combining femtosecond Fe K-alpha and K-beta X-ray emission spectroscopy (XES) with Fe K-edge X-ray absorption near-edge structure (XANES), we demonstrate that the photocycle of ferric Cyt c is entirely due to a cascade among excited spin states of the iron ion, causing the ferric heme to undergo doming, which we identify. We also argue that this pattern is common to a wide diversity of ferric heme proteins, raising the question of the biological relevance of doming in such proteins.

The photoinduced dynamics of ferric Cytochrome c was investigated by ultrafast non-resonant X-ray emission (XES) and X-Ray Absorption (XAS) spectroscopies, and a cascade through high spin states accompanied by heme doming are observed for the first time.

OLED technology beyond small or expensive devices requires light-emitters, luminophores, based on earth-abundant elements. Understanding and experimental verification of charge transfer in luminophores are needed for this development. An organometallic multicore Cu complex comprising Cu–C and Cu–P bonds represents an underexplored type of luminophore. To investigate the charge transfer and structural rearrangements in this material, we apply complementary pump-probe X-ray techniques: absorption, emission, and scattering including pump-probe measurements at the X-ray free-electron laser SwissFEL. We find that the excitation leads to charge movement from C- and P- coordinated Cu sites and from the phosphorus atoms to phenyl rings; the Cu core slightly rearranges with 0.05 Å increase of the shortest Cu–Cu distance. The use of a Cu cluster bonded to the ligands through C and P atoms is an efficient way to keep structural rigidity of luminophores. Obtained data can be used to verify computational methods for the development of luminophores., Nature Communications, 11 (1), ISSN:2041-1723

Background and Purpose:: Extracapsular spread (ECS) is frequent, but the specific sites of relapse are seldom given in the literature. In this study it was evaluated, if ECS might be an indicator for axillary irradiation. Patients and Methods:: After a retrospective review of pathology reports, the information about ECS was available in 254 lymph node-positive patients: ECS was absent in 34% (ECS-negative; n = 87) and present in 66% (ECS-positive; n = 167). All patients were irradiated locally, 78 patients got periclavicular and 74 axillary irradiation (median total dose: 50.4 Gy). 240/254 patients (94.5%) received systemic treatment/s. Mean follow-up was 46 months. Results:: The regional relapse rate was 4.6% without ECS versus 9.6% with ECS. The 5-year axillary relapse-free survival was 100% in ECS-negative and 90% in ECS-positive patients (p = 0.01), whereas corresponding values for periclavicular relapse-free survival (with ECS: 91% ± 4%; without ECS: 94% ± 3%; p = 0.77) and local relapse-free survival (with ECS: 86% ± 4%; without ECS: 91% ± 3%; p = 0.69) were not significantly different. χ2-tests revealed a high correlation of ECS with T-stage, number of positive lymph nodes and progesterone receptor status, comparisons with estrogen receptor, grade, or age were not significant. In multivariate analysis number of positive lymph nodes was solely significant for regional failure. Dividing the patients into those with one to three and those with four or more positive lymph nodes, ECS lost its significance for axillary failure. Conclusion:: ECS was accompanied by an enhanced axillary failure rate in univariate analysis, which was no longer true after adjusting for the number of positive lymph nodes

p-Dioxane is non-polar, hence its rotational constants cannot be determined by microwave rotationalcoherence spectroscopy (RCS). We perform high-resolution gas-phase rotational spectroscopy ofpara-dioxane-h8and -d8using femtosecond time-resolved Raman RCS in a gas cell atT= 293 Kand in a pulsed supersonic jet atT∼130 K. The inertial tensor ofp-dioxane-h8is strongly asym-metric, leading to a large number of asymmetry transients in its RCS spectrum. In contrast, thed8-isotopomer is a near-oblate symmetric top that exhibits a much more regular RCS spectrum withfew asymmetry transients. Fitting the fs Raman RCS transients ofp-dioxane-h8to an asymmetric-top model yields the ground-state rotational constantsA0= 5084.4(5) MHz,B0= 4684(1) MHz,C0= 2744.7(8) MHz, and (A0+ B0)/2 = 4884.5(7) MHz (±1σ). The analogous values forp-dioxane-d8areA0= 4083(2) MHz,B0= 3925(4) MHz,C0= 2347.1(6) MHz, and (A0+ B0)/2 = 4002.4(6) MHz.We determine the molecular structure with a semi-experimental approach involving the highly corre-lated coupled-cluster singles, doubles and iterated triples method and the cc-pCVXZ basis set seriesfrom double- to quadruple-zeta (X = D, T, Q). Combining the calculated vibrationally averaged rotational constants Acalc0(X),Bcalc0(X),Ccalc0(X) for increasing basis-set sizeXwith non-linear extrap-olation to the experimental constantsAexp0,Bexp0,Cexp0allows to determine the equilibrium groundstate structure ofp-dioxane. For instance, the equilibrium C–C and C–O bond lengths arere(CC)= 1.5135(3) Å andre(CO) = 1.4168(4) Å, and the four axial C–H bond lengths are 0.008 Å longerthan the four equatorial ones. The latter is ascribed to thetrans-effect (anomeric effect), i.e., the partialdelocalization of the electron lone-pairs on the O atoms that are orientedtrans, relative to the axialCH bonds.

We present an approach to determine the absolute thickness profile of flat liquid jets, which takes advantage of the information of thin film interference combined with light absorption, both captured in a single microscopic image. The feasibility of the proposed method is demonstrated on our compact experimental setup used to generate micrometer thin, free-flowing liquid jet sheets upon collision of two identical laminar cylindrical jets. Stable operation was achieved over several hours of the flat jet in vacuum (10-4 mbar), making the system ideally suitable for soft x-ray photon spectroscopy of liquid solutions. We characterize the flat jet size and thickness generated with two solvents, water and ethanol, employing different flow rates and nozzles of variable sizes. Our results show that a gradient of thickness ranging from a minimal thickness of 2 µm to over 10 µm can be found within the jet surface area. This enables the tunability of the sample thickness in situ, allowing the optimization of the transmitted photon flux for the chosen photon energy and sample. We demonstrate the feasibility of x-ray absorption spectroscopy experiments in transmission mode by measuring at the oxygen K-edge of ethanol. Our characterization method and the description of the experimental setup and its reported performance are expected to expand the range of applications and facilitate the use of flat liquid jets for spectroscopy experiments.