Expansion and characterization of immune suppressive CD56(bright)Perforin(-) regulatory-like natural killer cells in chronic graft-versus-host disease.

Background: Chronic graft-versus-host disease (cGvHD) is a major cause of morbidity and mortality after Hematopoietic Stem Cell Transplantation (HSCT). Previously, in large patient cohorts, we identified increased numbers of CD56Perforin regulatory-like NK cells (NK-like) associated with cGvHD suppression. Thus, we hypothesized that NK-like cells may be a potential candidate for cGvHD cell therapy.

Circulating cell-free mitochondrial DNA as a diagnostic and prognostic biomarker in chronic and late acute graft-versus-host disease in children.

In an earlier study, we found that mitochondrial DNA (mtDNA) concentration is elevated in adults with chronic graft-versus-host disease (cGvHD), acting as an endogenous source of TLR9 agonists to augment B-cell responses. To validate this in children, we evaluated mtDNA plasma expression in a large pediatric cohort (ABLE/PBMTC 1202 study). Plasma cell-free mtDNA (cf-mtDNA) copy numbers were measured in 202 pediatric patients using quantitative Droplet Digital polymerase chain reaction (ddPCR).

Ultrafast response of spontaneous photovoltaic effect in 3R-MoS-based heterostructures.

Rhombohedrally stacked MoS has been shown to exhibit spontaneous polarization down to the bilayer limit and can sustain a strong depolarization field when sandwiched between graphene. Such a field gives rise to a spontaneous photovoltaic effect without needing any p-n junction. In this work, we show that the photovoltaic effect has an external quantum efficiency of 10% for devices with only two atomic layers of MoS at low temperatures, and identify a picosecond-fast photocurrent response, which translates to an intrinsic device bandwidth at ∼100-GHz level.

A diagnostic classifier for pediatric chronic graft-versus-host disease: results of the ABLE/PBMTC 1202 study.

The National Institutes of Health Consensus criteria for chronic graft-versus-host disease (cGVHD) diagnosis can be challenging to apply in children, making pediatric cGVHD diagnosis difficult. We aimed to identify diagnostic pediatric cGVHD biomarkers that would complement the current clinical criteria and help differentiate cGVHD from non-cGVHD. The Applied Biomarkers of Late Effects of Childhood Cancer (ABLE) study, open at 27 transplant centers, prospectively evaluated 302 pediatric patients after hematopoietic cell transplant (234 evaluable).

CD56bright CD16- natural killer cells as an important regulatory mechanism in chronic graft--host disease.

Chronic graft-versus-host disease (cGvHD) is a major cause of morbidity after hematopoietic stem cell transplantation (HSCT). In large patient populations, we have shown a CD56bright natural killer (NK) population to strongly associate with a lack of cGvHD and we hypothesize that these cells function to suppress cGvHD. We aimed to isolate and define the characteristics of regulatory NK (NKreg) cells associated with suppression of cGvHD.

Metabolomic identification of α-ketoglutaric acid elevation in pediatric chronic graft-versus-host disease.

Chronic graft-versus-host disease (cGVHD) is the most common cause for non-relapse mortality postallogeneic hematopoietic stem cell transplant (HSCT). However, there are no well-defined biomarkers for cGVHD or late acute GVHD (aGVHD). This study is a longitudinal evaluation of metabolomic patterns of cGVHD and late aGVHD in pediatric HSCT recipients.

Characterization of fluorescent chlorophyll charge-transfer states as intermediates in the excited state quenching of light-harvesting complex II.

Light-harvesting complex II (LHCII) is the major antenna complex in higher plants and green algae. It has been suggested that a major part of the excited state energy dissipation in the so-called "non-photochemical quenching" (NPQ) is located in this antenna complex. We have performed an ultrafast kinetics study of the low-energy fluorescent states related to quenching in LHCII in both aggregated and the crystalline form.

Striking the right balance of intermolecular coupling for high-efficiency singlet fission.

Singlet fission is a process that splits collective excitations, or excitons, into two with unity efficiency. This exciton splitting process, unique to molecular photophysics, has the potential to considerably improve the efficiency of optoelectronic devices through more efficient light harvesting. While the first step of singlet fission has been characterized in great detail, subsequent steps critical to achieving overall highly-efficient singlet-to-triplet conversion are only just beginning to become well understood.

Coherent wavepackets in the Fenna-Matthews-Olson complex are robust to excitonic-structure perturbations caused by mutagenesis.

Femtosecond pulsed excitation of light-harvesting complexes creates oscillatory features in their response. This phenomenon has inspired a large body of work aimed at uncovering the origin of the coherent beatings and possible implications for function. Here we exploit site-directed mutagenesis to change the excitonic level structure in Fenna-Matthews-Olson (FMO) complexes and compare the coherences using broadband pump-probe spectroscopy.

Photoluminescence of Functionalized Germanium Nanocrystals Embedded in Arsenic Sulfide Glass.

Embedding metallic and semiconductor nanoparticles in a chalcogenide glass matrix effectively modifies the photonic properties. Such nanostructured materials could play an important role in optoelectronic devices, catalysis, and imaging applications. In this work, we fabricate and characterize germanium nanocrystals (Ge NCs) embedded in arsenic sulfide thin films by pulsed laser ablation in aliphatic amine solutions.

Light Absorption and Energy Transfer in the Antenna Complexes of Photosynthetic Organisms.

The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing molecules (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solutions for light harvesting. In this review, we describe the underlying photophysical principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET).

Observation of Two Triplet-Pair Intermediates in Singlet Exciton Fission.

Singlet fission is an excitation multiplication process in molecular systems that can circumvent energy losses and significantly boost solar cell efficiencies; however, the nature of a critical intermediate that enables singlet fission and details of its evolution into multiple product excitations remain obscure. We resolve the initial sequence of events comprising the fission of a singlet exciton in solids of pentacene derivatives using femtosecond transient absorption spectroscopy. We propose a three-step model of singlet fission that includes two triplet-pair intermediates and show how transient spectroscopy can distinguish initially interacting triplet pairs from those that are spatially separated and noninteracting.

Energy transfer pathways in light-harvesting complexes of purple bacteria as revealed by global kinetic analysis of two-dimensional transient spectra.

Excited state dynamics in LH2 complexes of two purple bacterial species were studied by broad-band two-dimensional electronic spectroscopy. The optical response was measured in the 500-600 nm spectral region on the 0-400 fs time scale. Global target analysis of two-dimensional (2D) transient spectra revealed the main energy transfer pathways between carotenoid S2, 1Bu(-) and S1 states and bacteriochlorophyll Qx state.

Broadband 2D electronic spectroscopy reveals a carotenoid dark state in purple bacteria.

Although the energy transfer processes in natural light-harvesting systems have been intensively studied for the past 60 years, certain details of the underlying mechanisms remain controversial. We performed broadband two-dimensional (2D) electronic spectroscopy measurements on light-harvesting proteins from purple bacteria and isolated carotenoids in order to characterize in more detail the excited-state manifold of carotenoids, which channel energy to bacteriochlorophyll molecules. The data revealed a well-resolved signal consistent with a previously postulated carotenoid dark state, the presence of which was confirmed by global kinetic analysis.

Two-Dimensional Electronic Spectroscopy Reveals Ultrafast Downhill Energy Transfer in Photosystem I Trimers of the Cyanobacterium Thermosynechococcus elongatus.

Two-dimensional electronic spectroscopy (2DES) was used to investigate the ultrafast energy-transfer dynamics of trimeric photosystem I of the cyanobacterium Thermosynechococcus elongatus. We demonstrate the ability of 2DES to resolve dynamics in a large pigment-protein complex containing ∼300 chromophores with both high frequency and time resolution. Monitoring the waiting-time-dependent changes of the line shape of the inhomogeneously broadened Qy(0-0) transition, we directly observe downhill energy equilibration on the 50 fs time scale.

On the nature of the "dark S*" excited state of β-carotene.

Femtosecond transient absorption spectroscopy has been applied to the isolated carotenoid β-carotene under a large variety of experimental conditions regarding solvent, temperature, excitation wavelength, and intensity to study the excited state relaxation dynamics in order to elucidate the origin of the so-called "dark S* state", which has been discussed very controversially in the literature. The results are analyzed in terms of lifetime density maps, and various kinetic models are tested on the data. The sample purification was found to be critical.

Electronic coherence provides a direct proof for energy-level crossing in photoexcited lutein and beta-carotene.

We investigate femtosecond transient absorption dynamics of lutein and beta-carotene. Strong oscillations up to about 400 fs are observed, depending on excitation or detection wavelength and solvent. We propose electronic quantum beats as the origin of these oscillations.

Spectroscopic properties of phenolic and quinoid carotenoids: a combined theoretical and experimental study.

For the natural carotenoid 3,3'-dihydroxyisorenieratene (DHIR) and two synthetic derivatives, 3,3'-dihydroxy-16,17,18,16',17',18'-hexanor-Phi,Phi-carotene (DHHC) and Phi,Phi-carotene-3,3'-dione (DHIRQ, isorenieratene-3,3'-dione), steady state absorption experiments and combined density functional and multi-reference configuration interaction calculations were carried out. In addition, femtosecond transient absorption spectra were recorded for DHIR. Due to their marked out-of-plane distortion in DHIR, the phenolic end groups participate only partially in the conjugation system.

Identifying mechanisms for therapeutic intervention in chordoma: c-Met oncoprotein.

Study Design: A human sacral chordoma cell line, CCL3, was established and in vitro characterization of c-Met oncoprotein in chordoma cells was performed.

Objective: Determination of whether c-Met plays an important role in chordoma's malignancy.

Summary Of Background Data: Chordomas are malignant life-threatening tumors that arise from the remnants of the notochord.

Chordoma and chondrosarcoma gene profile: implications for immunotherapy.

Chordoma and chondrosarcoma are malignant bone tumors characterized by the abundant production of extracellular matrix. The resistance of these tumors to conventional therapeutic modalities has prompted us to delineate the gene expression profile of these two tumor types, with the expectation to identify potential molecular therapeutic targets. Furthermore the transcriptional profile of chordomas and chrondrosarcomas was compared to a wide variety of sarcomas as well as to that of normal tissues of similar lineage, to determine whether they express unique gene signatures among other tumors of mesenchymal origin, and to identify changes associated with malignant transformation.

The role of extracellular factors in human metastatic chordoma cell growth in vitro.

Study Design: Human metastatic chordoma cells were isolated, and initial in vitro characterization was performed. Biochemical and physiologic changes were observed in response to pH, oxygen, and glucose.

Objective: The extracellular microenvironment directly affects metastatic chordoma cell phenotype in vitro.

[Fluorescence characteristics and photophysical parameters of aggregates of light-harvesting chlorophyll a/b complexes].

Changes in the fluorescence characteristics and molecular photophysical parameters induced by disaggregation of light-harvesting chlorophyll a/b complexes isolated from pea were studied. Disaggregation was achieved by increasing the concentration of the detergent triton X-100 (concentration range 0-230 microM, chlorophyll concentration 2.45 microg/ml).

[Hyperhydration and the cardiovascular system in patients receiving hemodialysis].

In order to evaluate the influence of volume overload on the cardiovascular system, patients on program hemodialysis were examined using ultrasonography and isotope ventriculography. The study revealed a doubtless correlation between hyperhydration, on the one hand, and arterial hypertension, an increased minute volume, and left ventricular hypertrophy, on the other. A growing left atrial contribution was shown to play an important role for the maintenance of an adequate left ventricular filling during a session of hemodialysis with ultrafiltration.

[Coronary artery disease after renal transplantation: epidemiology, risk factors, and surgical approaches to treatment].

Coronary artery disease (CAD) is the main cause of death in renal transplant recipients. The aim of the present study was to determine the frequency and risk factors of post-transplantation CAD and its influence on the long-term results of surgery, as well as to evaluate the efficiency of myocardial revascularization in patients with severe CAD. Analysis of the observation of 479 renal recipients (332 men and 147 women) aged 38.