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Ferrocene is one of the most common electron donors, and mapping its ligand-field excited states is critical to designing donor-acceptor (D-A) molecules with long-lived charge transfer states. Although 3 (d-d) states are commonly invoked in the photophysics of ferrocene complexes, mention of the high-spin 5 (d-d) state is scarce. Here, we provide clear evidence of 5 (d-d) formation in a bimetallic D-A molecule, ferrocenyl cobaltocenium hexafluorophosphate ([FcCc]PF 6 ). Femtosecond optical transient absorption (OTA) spectroscopy reveals two distinct electronic excited states with 30 and 500 ps lifetimes. Using a combination of ultraviolet, visible, near-infrared, and short-wave infrared probe pulses, we capture the spectral features of these states over an ultrabroadband range spanning 320 to 2200 nm. Time-dependent density functional theory (DFT) calculations of the lowest triplet and quintet states, both primarily Fe(II) (d-d) in character, qualitatively agree with the experimental OTA spectra, allowing us to assign the 30 ps state as the 3 (d-d) state and the 500 ps state as the high-spin 5 (d-d) state. To confirm the ferrocene-centered high-spin character of the 500 ps state, we performed X-ray transient absorption (XTA) spectroscopy at the Fe and Co K edges. The Fe K-edge XTA spectrum at 150 ps shows a red shift of the absorption edge that is consistent with an Fe(II) high-spin state, as supported by ab initio calculations. The transient signal detected at the Co K-edge is 50× weaker, confirming the ferrocene-centered character of the excited state. Fitting of the transient extended X-ray absorption fine structure region yields an Fe-C bond length increase of 0.25 ± 0.1 Å in the excited state, as expected for the high-spin state based on DFT. Altogether, these results demonstrate that the high-spin state of ferrocene should be considered when designing donor-acceptor assemblies for photocatalysis and photovoltaics.

Photoassisted catalysis using Ni complexes is an emerging field for cross-coupling reactions in organic synthesis. However, the mechanism by which light enables and enhances the reactivity of these complexes often remains elusive. Although optical techniques have been widely used to study the ground and excited states of photocatalysts, they lack the specificity to interrogate the electronic and structural changes at specific atoms. Herein, we report metal-specific studies using transient Ni L- and K-edge X-ray absorption spectroscopy of a prototypical Ni photocatalyst, (dtbbpy)Ni( o -tol)Cl (dtb = 4,4'-di- tert -butyl, bpy = bipyridine, o -tol = ortho -tolyl), in solution. We unambiguously confirm via direct experimental evidence that the long-lived (∼5 ns) excited state is a tetrahedral metal-centered triplet state. These results demonstrate the power of ultrafast X-ray spectroscopies to unambiguously elucidate the nature of excited states in important transition-metal-based photocatalytic systems.

Disentangling electronic and thermal effects in photoexcited perovskite materials is crucial for photovoltaic and optoelectronic applications but remains a challenge due to their intertwined nature in both the time and energy domains. In this study, we employed temperature-dependent variable-angle spectroscopic ellipsometry, density functional theory calculations, and broadband transient absorption spectroscopy spanning the visible to mid-to-deep-ultraviolet (UV) ranges on MAPbBr 3 thin films. The use of deep-UV detection opens a new spectral window that enables the exploration of high-energy excitations at various symmetry points within the Brillouin zone, facilitating an understanding of the ultrafast responses of the UV bands and the underlying mechanisms governing them. Our investigation reveals that the photoinduced spectral features remarkably resemble those generated by pure lattice heating, and we disentangle the relative thermal and electronic contributions and their evolutions at different delay times using combinations of decay-associated spectra and temperature-induced differential absorption. The results demonstrate that the photoinduced transients possess a significant thermal origin and cannot be attributed solely to electronic effects. Following photoexcitation, as carriers (electrons and holes) transfer their energy to the lattice, the thermal contribution increases from ∼15% at 1 ps to ∼55% at 500 ps and subsequently decreases to ∼35-50% at 1 ns. These findings elucidate the intricate energy exchange between charge carriers and the lattice in photoexcited perovskite materials and provide insights into the limited utilization efficiency of photogenerated charge carriers.

The evolution of charge carriers in photoexcited room temperature ZnO nanoparticles in solution is investigated using ultrafast ultraviolet photoluminescence spectroscopy, ultrafast Zn K-edge absorption spectroscopy, and ab initio molecular dynamics (MD) simulations. The photoluminescence is excited at 4.66 eV, well above the band edge, and shows that electron cooling in the conduction band and exciton formation occur in <500 fs, in excellent agreement with theoretical predictions. The x-ray absorption measurements, obtained upon excitation close to the band edge at 3.49 eV, are sensitive to the migration and trapping of holes. They reveal that the 2 ps transient largely reproduces the previously reported transient obtained at 100 ps time delay in synchrotron studies. In addition, the x-ray absorption signal is found to rise in ∼1.4 ps, which we attribute to the diffusion of holes through the lattice prior to their trapping at singly charged oxygen vacancies. Indeed, the MD simulations show that impulsive trapping of holes induces an ultrafast expansion of the cage of Zn atoms in <200 fs, followed by an oscillatory response at a frequency of ∼100 cm -1 , which corresponds to a phonon mode of the system involving the Zn sub-lattice., Competing Interests: The authors have no conflicts to disclose., (© 2023 Author(s).)

Understanding the electronic structure and dynamics of semiconducting nanomaterials at the atomic level is crucial for the realization and optimization of devices in solar energy, catalysis, and optoelectronic applications. We report here on the use of ultrafast X-ray linear dichroism spectroscopy to monitor the carrier dynamics in epitaxial ZnO nanorods after band gap photoexcitation. By rigorously subtracting out thermal contributions and conducting ab initio calculations, we reveal an overall depletion of absorption cross sections in the transient X-ray spectra caused by photogenerated charge carriers screening the core-hole potential of the X-ray absorbing atom. At low laser excitation densities, we observe phase-space filling by excited electrons and holes separately. These results pave the way for carrier- and element-specific probing of charge transfer dynamics across heterostructured interfaces with ultrafast table-top and fourth-generation X-ray sources.

The development of next-generation perovskite-based optoelectronic devices relies critically on the understanding of the interaction between charge carriers and the polar lattice in out-of-equilibrium conditions. While it has become increasingly evident for CsPbBr 3 perovskites that the Pb-Br framework flexibility plays a key role in their light-activated functionality, the corresponding local structural rearrangement has not yet been unambiguously identified. In this work, we demonstrate that the photoinduced lattice changes in the system are due to a specific polaronic distortion, associated with the activation of a longitudinal optical phonon mode at 18 meV by electron-phonon coupling, and we quantify the associated structural changes with atomic-level precision. Key to this achievement is the combination of time-resolved and temperature-dependent studies at Br K and Pb L 3 X-ray absorption edges with refined ab initio simulations, which fully account for the screened core-hole final state effects on the X-ray absorption spectra. From the temporal kinetics, we show that carrier recombination reversibly unlocks the structural deformation at both Br and Pb sites. The comparison with the temperature-dependent XAS results rules out thermal effects as the primary source of distortion of the Pb-Br bonding motif during photoexcitation. Our work provides a comprehensive description of the CsPbBr 3 perovskites' photophysics, offering novel insights on the light-induced response of the system and its exceptional optoelectronic properties.

We review our recent results on the implementation of picosecond (ps) X-ray absorption spectroscopy to probe the electronic and geometric structure of centres formed by photoexcitation of solar materials such as TiO2 polymorphs and inorganic Cs-based perovskites. The results show electron localization at Ti defects in TiO2 anatase and rutile and small hole polaron formation in the valence band of CsPbBr3, all within 80 ps. This method is promising for the study of the ultrafast time scales of such processes, especially with the advent of the Swiss X-ray Free Electron Laser (SwissFEL).

Objective: Recent data from the literature indicate gynecological cancers (GCs) as sentinel cancers for a diagnosis of Lynch syndrome (LS). Clinical approaches to identifying LS have low sensitivity, whereas somatic tests on GCs may be a more sensitive and cost-effective strategy., Methods: A series of 78 GCs belonging to 74 patients sent to the Genetic Counselling Service were investigated using microsatellite instability, immunohistochemical expression of mismatch repair (MMR) genes, and MLH1 promoter methylation., Results: The presence of microsatellite instability was observed in 67.5% of GCs, and the absence of immunohistochemical expression of at least 1 of the 4 MMR proteins was observed in 71.4% of GCs, showing 96.1% concordance between the methods. Methylation analysis using methylation specific multiplex ligation-dependent probe amplification performed on 35 samples revealed MLH1 promoter hypermethylation in 18 cases (54%). Molecular analysis identified 36 LS carriers of MMR variants (27 pathogenetic and 9 variants of uncertain significance), and, interestingly, 3 LS patients had MLH1 methylated GC.With regard to histological features, LS-related GCs included endocervical cancers and also histological types different from the endometrioid cancers. The presence of peritumoral lymphocytes in GCs was statistically associated with LS tumors., Conclusions: Somatic analysis is a useful strategy to distinguish sporadic from LS GC. Our data allow the identification of a subset of LS patients otherwise unrecognized on the basis of clinical or family history alone. In addition, our results indicate that some clinicopathological features including age of GC diagnosis; presence of peritumoral lymphocytes; isthmic, endocervical sites, and body mass index value could be useful criteria to select patients for genetic counseling.

Ultrafast interfacial electron transfer in sensitized solar cells has mostly been probed by visible-to-terahertz radiation, which is sensitive to the free carriers in the conduction band of the semiconductor substrate. Here, we demonstrate the use of deep-ultraviolet continuum pulses to probe the interfacial electron transfer, by detecting a specific excitonic transition in both N719-sensitized anatase TiO 2 and wurtzite ZnO nanoparticles. Our results are compared to those obtained on bare nanoparticles upon above-gap excitation. We show that the signal upon electron injection from the N719 dye into TiO 2 is dominated by long-range Coulomb screening of the final states of the excitonic transitions, whereas in sensitized ZnO it is dominated by phase-space filling. The present approach offers a possible route to detecting interfacial electron transfer in a broad class of systems, including other transition metal oxides or sensitizers.

We describe the facilities for ultraviolet studies in the femtosecond to nanosecond time domain. These facilities consist of: i) a set-up for deep-ultraviolet spectroscopy in the 260-380 nm range in both pump and probe pulses for transient absorption/reflectivity or two-dimensional spectroscopy studies; ii) a set-up for ultrafast fluorescence measurements with detection down to 300 nm. The capabilities of these set-ups are demonstrated by examples on molecular systems, biosystems, nanoparticles and solid materials.

Background: Satellite cells are quiescent resident muscle stem cells that present an important potential to regenerate damaged tissue. However, this potential is diminished once they are removed from their niche environment in vivo, prohibiting the long-term study and genetic investigation of these cells. This study therefore aimed to provide a novel biomaterial platform for the in-vitro culture of human satellite cells that maintains their stem-like quiescent state, an important step for cell therapeutic studies., Methods: Human muscle satellite cells were isolated from two donors and cultured on soft biopolymeric films of controlled stiffness. Cell adhesive phenotype, maintenance of satellite cell quiescence and capacity for gene manipulation were investigated using FACS, western blotting, fluorescence microscopy and electron microscopy., Results: About 85% of satellite cells cultured in vitro on soft biopolymer films for 3 days maintained expression of the quiescence marker Pax7, as compared with 60% on stiffer films and 50% on tissue culture plastic. The soft biopolymeric films allowed satellite cell culture for up to 6 days without renewing the media. These cells retained their stem-like properties, as evidenced by the expression of stem cell markers and reduced expression of differentiated markers. In addition, 95% of cells grown on these soft biopolymeric films were in the G0/G1 stage of the cell cycle, as opposed to those grown on plastic that became activated and began to proliferate and differentiate., Conclusions: Our study identifies a new biomaterial made of a biopolymer thin film for the maintenance of the quiescence state of muscle satellite cells. These cells could be activated at any point simply by replating them onto a plastic culture dish. Furthermore, these cells could be genetically manipulated by viral transduction, showing that this biomaterial may be further used for therapeutic strategies.

We report on an element-selective study of the fate of charge carriers in photoexcited inorganic CsPbBr 3 and CsPb(ClBr) 3 perovskite nanocrystals in toluene solutions using time-resolved X-ray absorption spectroscopy with 80 ps time resolution. Probing the Br K-edge, the Pb L 3 -edge, and the Cs L 2 -edge, we find that holes in the valence band are localized at Br atoms, forming small polarons, while electrons appear as delocalized in the conduction band. No signature of either electronic or structural changes is observed at the Cs L 2 -edge. The results at the Br and Pb edges suggest the existence of a weakly localized exciton, while the absence of signatures at the Cs edge indicates that the Cs + cation plays no role in the charge transport, at least beyond 80 ps. This first, time-resolved element-specific study of perovskites helps understand the rather modest charge carrier mobilities in these materials.

This is the first report describing a case where prolonged, severe malabsorption from brown bowel syndrome progressed to multifocally spread small bowel adenocarcinoma. This case involves a female patient who was initially diagnosed with chronic jejunitis associated with primary diffuse lymphangiectasia at the age of 26 years. The course of the disease was clinically, endoscopically, and histologically followed for 21 years until her death at the age 47 due to multifocal, metastasizing adenocarcinoma of the small bowel. Multiple lipofuscin deposits (so-called brown bowel syndrome) and severe jejunitis were observed microscopically, and sections of the small bowel showed dense lymphoplasmacytic infiltration of the lamina propria as well as blocked lymphatic vessels. After several decades, multifocal nests of adenocarcinoma cells and extensive, flat, neoplastic mucosal proliferations were found only in the small bowel, along with a loss of the mismatch repair protein MLH1 as a long-term consequence of chronic jejunitis with malabsorption. No evidence was found for hereditary nonpolyposis colon carcinoma syndrome. This article demonstrates for the first time multifocal carcinogenesis in the small bowel in a malabsorption syndrome in an enteritis-dysplasia-carcinoma sequence.

Background: Conventional colonoscopy (CC) is the gold standard for diagnostic examination of the colon. However, the overall acceptance of this procedure is low due to patient fears of complications or embarrassment. Colon capsule endoscopy (CCE) represents a minimally invasive, patient-friendly procedure that offers complete visualization of the entire intestine., Objective: To assess the PillCam Colon 2 (Given Imaging Ltd, Israel) capsule with regard to feasibility, sensitivity and specificity for the detection of colonic pathologies and additional recorded extracolonic findings., Methods: CCE was performed before CC in patients indicated for CC for known or suspected colonic disease. The results of both techniques were compared with regard to polyp detection. Additionally, bowel preparation and extracolonic pathologies were analyzed., Results: Twenty-four patients (mean age 51.1 years) were included in the analysis. Visualization of the colon was complete in 23 CCs and 17 CCEs. No adverse events or major technical failures occurred. CC detected 47 polyps and CCE detected 43 polyps of any size (per-finding sensitivity 90.9%, specificity 67.6%). The accuracy of CCE in detecting polyp carriers was 81.5% (per-patient analysis). On average, the colon was adequately cleansed in 90.1% of patients. CCE identified esophageal, gastric and small bowel pathologies in seven (24%), nine (38%) and 14 (58%) patients, respectively., Conclusions: CCE proved to be technically feasible and safe. Acceptable sensitivity and moderate specificity levels in polyp detection were recorded. Bowel preparation was adequate in most patients. Because extracolonic pathologies were effectively visualized, new indications for the PillCam Colon 2 may be defined.

Background: Bacterial vaginosis (BV) is the most prevalent vaginal disorder in adult women worldwide. A number of clinical studies indicate that re-establishment of the physiological ecosystem by re-colonization of vaginal mucosa by lactobacilli may be an effective therapy for BV both after initial antimicrobial therapy or when given alone. A vaginal pH <4.5 is considered physiological and its measurement has been reported as an objective parameter, very sensitive to alterations of vaginal microflora and correlated with clinically relevant BV., Objective: The aims of this work were to assess the effectiveness of a long-term (24 months) intravaginal treatment with Lactobacillus rhamnosus (NORMOGIN) on the vaginal pH and on the clinical symptoms in a group of 40 women affected by BV diagnosed by the Amsel criteria., Method: A prospective open clinical trial was performed in 40 consecutive cases evaluated for B.V. by the Amsel criteria., Results: Vaginal pH was above the physiological value of 4.5 in 36 out of 40 patients at the first visit. It returned under 4.5 value in 24/40 and 32/40 women after 12 and 24 months of treatment, respectively. pH values were significantly decreased at 12 month treatment (P < 0.001) and further reduction in pH values was found at 24 months of treatment (P < 0.02 vs. 12 months). The gradual return to a vaginal physiological pH was associated with a reduction of the intensity of symptoms as shown by the decrease in the symptoms score., Conclusions: The present study supports the use of pH measurement for sensitive, objective, and simple therapy follow-up in women with BV and shows that long-term administration of vaginal tablets containing Lactobacillus rhamnosus represents an effective and safe treatment for restoring the physiological vaginal pH and controlling BV symptoms.

Background: The prognosis of patients with liver metastases from breast cancer is commonly poor. After initial diagnosis of hepatic metastases, a median survival time of 1-20 months can be expected. The definition of prognostic factors for such patients may influence therapeutic decisions. In particular, the characterization of patients who can expect long-term survival could assist in optimizing treatment., Methods: We retrospectively studied n = 350 patients with liver metastases from breast cancer. All patients were stratified following their survival after occurrence of liver metastases. Kaplan-Meier studies were performed, as well as univariate and multivariate analyses of several clinical, histopathological and therapeutic factors., Results: Median survival time was 14 months. N = 66 (18.9%) patients survived longer than 36 months after the primary diagnosis. Multivariate analysis showed prognostic relevance for the time interval between the primary diagnosis of breast cancer and the initial diagnosis of hepatic metastases (p < 0.05). Furthermore, prognostic relevance was found for the pattern of metastasization (p < 0.05) and for signs of hepatic dysfunction (ascites, jaundice, p < 0.005). Univariate analysis showed a prognostic benefit for patients with an expression of Ki-67 < 20%, p53 < 50% and a positive hormonal receptor status. Patients who received a regional therapy survived on average longer than patients who were only treated systemically (33 versus 11 months, p < 0.001)., Conclusions: Consideration of prognostic implications of the described parameters may help to find the most appropriate treatment for patients with liver metastases from breast cancer. The possibility of local therapeutic interventions should be considered in a defined subgroup.

Background: In surgical treatment of morbid obesity, maintaining a restrictive anastomosis is key to long-range success. However, laparoscopic Roux-en-Y gastric bypass (LRYGB) may result in gastrojejunal (GJ) stricture, requiring treatment in up to 27% of patients., Methods: This is a retrospective review of the outcome of 223 consecutive LRYGB patients. Patients developing stricture received standard endoscopic balloon dilation by the same surgeon. Stricture and nonstricture groups were compared for excess body weight loss (EBWL) at 1, 3, 6, and 12 months., Results: GJ stricture requiring dilation occurred in 38 patients (17%). After dilation all patients were relieved of stricture symptoms and none required revision. By 12 months, patients with stricture had an EBWL of 86% compared with nonstrictured patients at 75%., Conclusion: Endoscopic balloon dilation is a safe and effective treatment option for GJ stricture. Improved weight loss occurred for patients with stricture requiring dilation.

Background: The immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare genodermatosis associated with dermatitis, enteropathy, type 1 diabetes, thyroiditis, hemolytic anemia, and thrombocytopenia. IPEX results from mutations of FOXP3, a gene located on the X chromosome that encodes a DNA-binding protein required for development of regulatory T cells. If untreated, affected males die early in life from malabsorption and other complications. To our knowledge, this syndrome has never been described in the dermatology literature., Observations: We studied an 11-year-old boy with IPEX. Mutation analysis revealed a G-->A transition (1150G>A) in exon 11, resulting in a putative substitution of Ala-->Thr at residue 384, within the DNA-binding site. Histopathologic examination of an active skin lesion revealed psoriasiform dermatitis. The lesions improved with clobetasol ointment. The patient also displayed alopecia universalis, which had been present since age 18 months, accompanied by longitudinal ridging of the nails. Lymphocyte challenge tests revealed a profound inability to synthesize interferon gamma (INF-gamma) and dysregulated production of other cytokines., Conclusions: IPEX is an often fatal genodermatosis associated with multiple autoimmune disorders. Cutaneous findings may include dermatitis, bullae, urticaria, alopecia universalis, and trachyonychia. Recognition of this life-threatening disorder is crucial for optimal treatment and genetic counseling.

Childhood celiac disease--gluten-sensitive enteropathy--is defined in its most salient form by malabsorption and disturbed growth in association with a specific histologic lesion of the small intestine. Celiac disease occurs in response to grain consumption in susceptible individuals. Although subtotal villus atrophy with crypt hyperplasia has, in the past, been considered essential for the diagnosis, a spectrum of histologic lesions are now appreciated. The advances in the field of diagnosis (specifically, the recent development of serologic diagnostic tests) have been instrumental in correlating the histopathology of patients with subtle clinical features of the disease. Through observations, an expansion of the clinical findings associated with the condition has evolved that has helped to unfold the pathophysiology. As a result, celiac disease is now recognized as an autoimmune enteropathy of the small intestine with a broad spectrum of clinical manifestations.

Hypothesis: Enteric leakage is a significant complication of the Roux-en-Y gastric bypass (RYGB) procedure that can be treated successfully., Design: Retrospective study of 400 consecutive RYGB patients from 1999-2002., Setting: Community hospital with a university surgical residency., Patients: Hospital records of 400 morbidly obese patients who underwent gastric bypass surgery were reviewed., Main Outcome Measures: Time of discovery of leak, location of leak, treatment, hospital stay, and mortality., Results: Twenty-one patients (5.25%) developed leaks. The mean body mass index (calculated as weight in kilograms divided by the square of height in meters) was 54.2. Thirteen patients were noted to develop a leak at the gastrojejunal anastomosis, with an average time to diagnosis of 7.0 days. Five of these patients underwent reexploration, and 8 were successfully treated with percutaneous drainage alone. Four patients developed leaks at the jejunojejunal anastomosis (mean time to diagnosis, 2.0 days). All of these patients required exploration, and 2 patients died. Four patients were noted to have leaks in other areas (average time to diagnosis, 3.5 days). Two patients were treated with drainage, and 2 underwent exploration. The average hospital stay of all patients was 33 days., Conclusions: Enteric leakage is a significant complication of the RYGB. Patients who are suspected of having an enteric leak because of signs of sepsis or hemodynamic instability require emergent exploration. Leaks that are more insidious may be treated successfully with percutaneous drainage. Aggressive exploration of patients who appear to be septic, and percutaneous drainage of insidiously developing leaks may decrease patients' morbidity and mortality.