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PIF1 is a 5′ to 3′ DNA helicase that can unwind double-stranded DNA and disrupt nucleic acid-protein complexes. In Saccharomyces cerevisiae, Pif1 plays important roles in mitochondrial and nuclear genome maintenance, telomere length regulation, unwinding of G-quadruplex structures, and DNA synthesis during break-induced replication. Some, but not all, of these functions are shared with other eukaryotes. To gain insight into the evolutionarily conserved functions of PIF1, we created pif1 null mutants in Drosophila melanogaster and assessed their phenotypes throughout development. We found that pif1 mutant larvae exposed to high concentrations of hydroxyurea, but not other DNA damaging agents, experience reduced survival to adulthood. Embryos lacking PIF1 fail to segregate their chromosomes efficiently during early nuclear divisions, consistent with a defect in DNA replication. Furthermore, loss of the BRCA2 protein, which is required for stabilization of stalled replication forks in metazoans, causes synthetic lethality in third instar larvae lacking either PIF1 or the polymerase delta subunit POL32. Interestingly, pif1 mutants have a reduced ability to synthesize DNA during repair of a double-stranded gap, but only in the absence of POL32. Together, these results support a model in which Drosophila PIF1 functions with POL32 during times of replication stress but acts independently of POL32 to promote synthesis during double-strand gap repair.

Prasentation, klinischer Verlauf und Outcome von Patienten mit primar biliarer Cholangitis (PBC) sind in Mitteleuropa nicht ausreichend beschrieben. Diese Arbeit untersucht demographische und klinische Daten und charakterisiert den Krankheitsverlauf der PBC am Patientenkollektiv am Universitatsklinikum Graz. Die Krankenakten von Patienten mit der Diagnose PBC, die im Zeitraum von 2004–2015 am Universitatsklinikum Graz in Betreuung waren, wurden retrospektiv untersucht. Erhoben wurden die Daten zum Zeitpunkt der Erstdiagnose und bei der letzten Kontrolle (Follow-up). Insgesamt wurden 95 Patienten (89 Frauen, 6 Manner) identifiziert. Das mediane Alter bei Erstdiagnose betrug 53 Jahre. Die alkalische Phosphatase (AP) war bei Erstdiagnose bei 60 % der Patienten um weniger als das 2‑Fache der Norm erhoht. 39 % der Patienten wiesen bei Erstdiagnose Symptome, wie Pruritus, Mudigkeit, Oberbauchbeschwerden oder eine Sicca-Symptomatik, auf. Eine Leberhistologie bei der Erstdiagnose lag bei 35 % aller Fallen vor (histologisches Stadium I nach Ludwig, n = 28; Stadium II, n = 5; Stadium III, n = 1; Stadium IV, n = 1). Das mediane Follow-up betrug 7 (1–21) Jahre. Die Mehrzahl der Patienten (69 %) hatte in der FibroScan®-Messung im Follow-up eine F0/F1-Fibrose. Eine Leberzirrhose lag in 10 Fallen (11 %) vor. Zwei mit der PBC assoziierte Todesfalle wurden verzeichnet. Ein inadaquates Ansprechen auf die Therapie mit Ursodesoxycholsaure lag in 30 % aller Falle vor. Zusammenfassend sind in unserem Kollektiv eine deutliche Erhohung der AP (>2- bis 4‑Fache der Norm) und ein schlechtes Outcome (Entwicklung einer Zirrhose, Tod, Transplantation) seltener als in der Literatur angegeben, wahrend demographische Daten durchaus mit denen aus anderen Arbeiten vergleichbar sind.

Recent evidence has shown that exposure to airborne particulate matter (PM) is associated with cognitive delay, depression, anxiety, autism, and neurodegenerative diseases; however, the role of PM in the etiology of these outcomes is not well-understood. Therefore, there is a need for controlled animal studies to better elucidate the causes and mechanisms by which PM impacts these health outcomes. We assessed the effects of gestational and early life exposure to traffic-related PM on social- and anxiety-related behaviors, cognition, inflammatory markers, and neural integrity in male rat juveniles. Gestating and lactating rats were exposed to PM from a Boston (MA, USA) traffic tunnel for 5 hours/day, 5 days/week for 6 weeks (3 weeks gestation, 3 weeks lactation). The target exposure concentration for the fine fraction of nebulized PM, measured as PM2.5, was 200 μg/m(3). To assess anxiety and cognitive function, F1 male juveniles underwent elevated platform, cricket predation, nest building, social behavior and marble burying tests at 32–60 days of age. Upon completion of behavioral testing, multiple cytokines and growth factors were measured in these animals and their brains were analyzed with diffusion tensor MRI to assess neural integrity. PM exposure had no effect on litter size or weight, or offspring growth; however, F1 litters developmentally exposed to PM exhibited significantly increased anxiety (p =0.04), decreased cognition reflected in poorer nest-organization (p =0.04), and decreased social play and allogrooming (p= 0.003). MRI analysis of ex vivo brains revealed decreased structural integrity of neural tissues in the anterior cingulate and hippocampus in F1 juveniles exposed to PM (p

Objectives: Rodents used in scientific research are typically housed in cages containing natural bedding materials. Despite extensive evidence of biological harm from inhaled particulate matter (PM), relatively little work has been performed to measure bedding-generated PM exposure in caged animals used in basic science research. Our objectives were to determine whether bedding-generated PM was present in significant concentrations in rodent cages and to identify the main factors affecting the accumulation and attenuation of bedding-generated PM inside cages. Materials and Methods: We measured PM2.5 concentrations in cages containing common bedding materials (pine, aspen, paper, and corncob) with filter top isolator absent or present on the cages. PM2.5 concentrations were monitored with rats inside cages as well as during artificial manipulation of the bedding (designed to simulate rodent activity). Results and Discussion: Upon rodent digging or mechanical/manual stirring, all four bedding materials produced significant increases in PM2.5 concentrations (as much as 100–200 µg/m3 PM2.5, 50- to 100-fold higher than during periods of no rodent activity), and concentrations in cages fitted with filter tops were an order of magnitude higher than in cages without filter tops. Elevated concentrations were sustained for longer durations in cages with filter tops (5–10 minutes) compared to cages with only bar lids (0–2 minutes). Conclusions: These results indicate that standard laboratory housing conditions can expose rodents to substantial levels of PM2.5. Bedding-generated PM has potential implications as an environmental agent in rodent studies.

PIF1 is a 5′ to 3′ DNA helicase that can unwind double-stranded DNA and disrupt nucleic acid-protein complexes. In Saccharomyces cerevisiae, Pif1 plays important roles in mitochondrial and nuclear genome maintenance, telomere length regulation, unwinding of G-quadruplex structures, and DNA synthesis during break-induced replication. Some, but not all, of these functions are shared with other eukaryotes. To gain insight into the evolutionarily conserved functions of PIF1, we created pif1 null mutants in Drosophila melanogaster and assessed their phenotypes throughout development. We found that pif1 mutant larvae exposed to high concentrations of hydroxyurea, but not other DNA damaging agents, experience reduced survival to adulthood. Embryos lacking PIF1 fail to segregate their chromosomes efficiently during early nuclear divisions, consistent with a defect in DNA replication. Furthermore, loss of the BRCA2 protein, which is required for stabilization of stalled replication forks in metazoans, causes synthetic lethality in third instar larvae lacking either PIF1 or the polymerase delta subunit POL32. Interestingly, pif1 mutants have a reduced ability to synthesize DNA during repair of a double-stranded gap, but only in the absence of POL32. Together, these results support a model in which Drosophila PIF1 functions with POL32 during times of replication stress but acts independently of POL32 to promote synthesis during double-strand gap repair.

Reservoirs represent a specific environmental component in many parts of the Earth, especially where water supply is limited. As is the case of the Moldavian hilly area, due to its dryness, the inhabitants created an extensive network of reservoirs since the medieval period, in the proximity of the settlement network. Over time, many dams were abandoned, while others have been relocated with impressive dynamics at a historical scale. In this paper, by analyzing old maps, LiDAR high-res DEMs, ERT surveys, and sediments, we have reconstructed the reservoir network's expansion in the last century at a regional scale and investigated the main geomorphologic characteristics of dams and associated landforms. In Jijia catchment (3386 km2) we found a total number of 1351 dams, of which 832 abandoned. 495 reservoirs were recognized on different topo maps dating from the 20th century, while 337 have been identified on DEMs. Two reservoirs were investigated in detail by field surveys, ERT surveys, profile digging, sediment analysis, and micro-sedimentological study, confirming lacustrine deposits according to the topographic reconstructions based on high-resolution LiDAR DEMs. These sedimentary lacustrine archives can substantially contribute to detailed paleoclimatic, paleohydrologic, and paleovegetation reconstruction in the study area.

There is convincing evidence that living close to major roadways and highways is associated with increased morbidity and mortality. Data indicate that traffic-related air pollution (TRAP) contribut...

Electronic and nuclear molecular wavepackets are a clear manifestation of the wavelike properties of matter at the very heart of quantum mechanics. In this work we demonstrate how electronic two-dimensional spectroscopy (2D) serves as a highly evolved tool for the simultaneous investigation of both phenomena. In further analysis and theoretical treatments, 2D spectra form an ideal basis for the discussion of electronic decoherence, vibrational relaxation and electron-phonon coupling.

In the present paper we introduce lake Bolătău, located in Obcina Feredeului, Eastern Carpathians (Romania), with seasonally controlled sedimentation and significant potential for generating precipitation sensitive proxy record. Two sediment cores were compared against each other in order to achieve a better understanding of the lateral discontinuity of observed microfacies and an accurate interpretation of the sedimentological data.

The energy level structure and dynamics of biomolecules are important for understanding their photoinduced function. In particular, the role of carotenoids in light-harvesting is heavily studied, yet not fully understood. The conventional approach to investigate these processes involves analysis of the third-order optical polarization in one spectral dimension. Here, we record two-dimensional correlation spectra for different time-orderings to characterize all components of the transient molecular polarization and the optical signal. Single- and double-quantum two-dimensional experiments provide insight into the energy level structure as well as the ultrafast dynamics of solvated beta-carotene. By analysis of the lineshapes, we obtain the transition energy and characterize the potential energy, surfaces of the involved states. We obtain direct experimental proof for an excited state absorption transition in the visible (S-2 -> S-n2). The signatures of this transition in pump-probe transients are shown to lead to strongly damped oscillations with characteristic pump and probe frequency dependence.

Two-dimensional electronic spectroscopy (2D) has been applied to beta-carotene in solution to shine new light on the ultrafast energy dissipation network in carotenoids. The ability of 2D to relieve spectral congestion provides new experimental grounds for resolving the rise of the excited state absorption signal between 18,000 and 19,000 cm(-1). In this spectral region, the pump-probe signals from ground state bleach and stimulated emission overlap strongly. Combined modeling of the time-evolution of 2D spectra as well as comparison to published pump-probe data allow us to draw conclusions on both the electronic structure of beta-carotene as well as the spectral densities giving rise to the observed optical lineshapes. To account for the experimental observations on all time scales, we need to include a transition in the visible spectral range from the first optically allowed excited state (S(2)-->S(n2)). We present data from frequency resolved transient grating and pump-probe experiments confirming the importance of this transition. Furthermore, we investigate the role and nature of the S* state, controversially debated in numerous previous studies. On the basis of the analysis of Feynman diagrams, we show that the properties of S*-related signals in chi(3) techniques like pump-probe and 2D can only be accounted for if S* is an excited electronic state. Against this background, we discuss a new interpretation of pump-deplete-probe and intensity-dependent pump-probe experiments.

We investigate the first steps of exciton dynamics in the course of nanometric band-to-band energy-transfer in a bi-tubular J-aggregate by employing two-dimensional (2D) coherent electronic spectroscopy. Coupled exciton states are mapped as typical off-diagonal signals in 2D frequency–frequency correlation spectra, with sub-20 femtosecond (fs) time resolution. The experiments enable to look beneath conventional incoherent population transfer by directly probing the early 100 fs quantum-kinetic regime. Our data, acquired at room temperature, indicate low-amplitude coherent motion, followed by quantum-dissipative population transfer. Exciton inter-band coherence with low intensity is observed in the high-energy cross-peak ( ω 3 > | ω 1 | ) as an electronic wave-packet following quantum-beat oscillation up to 100 fs , whereas ongoing exciton relaxation is imaged in the low-energy cross-peak ( ω 3 | ω 1 | ) as typical streaked signals along the coherence frequency ω 1 . Solvent induced band symmetry breaking and tube expansion create spatial disorder and densities-of-states with dipoles of minor collectivity that affect both the morphology and electronic band features by broadening the peaks and streaks and promoting the irreversibility of tube-to-tube transfer on longer time-scales.

Identifying the pathways and timescales of excitation energy transfer is a central goal in the design of artificial light harvesting systems and energy transporting wires. Coherent femtosecond two-dimensional electronic spectroscopy provides this information for a molecular nanotube by correlating excitonic absorption and emission frequencies at various delay periods. In combination with simulations based on a coupled electronic oscillator model the experiments reveal the electronic coupling pattern and show the various energy transfer pathways into the lowest accessible state.

We report and analyze oscillatory behavior of lineshapes in two-dimensional photon-echo relaxation spectra of a perylene-based dye molecule, whose four-wave-mixing signals are strongly modulated by coupling to low-frequency vibrational modes. Vibrational wavepacket motion is found to induce a pronounced beating of the anti-diagonal absorptive peak width, accompanied by orientational changes in the dispersive signal part. The effects are reproduced well by simulations based on a Brownian oscillator model, and can be assigned to periodic alternations in the relative amplitudes of rephasing and non-rephasing contributions to the spectrum.

We study the sub-picosecond exciton dynamics of the prototypical soluble conjugated polymer poly[2-(2′-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene] (MEH-PPV) by comparative three-pulse photon-echo peak-shift and transient grating measurements, performed under excitation energy tuning conditions. The strong sensitivity of signal decays to the chosen excitation energy is ascribed to the interplay of inter- and intra-segmental relaxation events in an ensemble of electronically coupled sites. As a result, the energetic site-to-site disorder and its contribution to the spectral lineshape is most reliably determined for excitation of the redmost part of the absorption spectrum. Comparing the data for the two solvents toluene and tetrahydrofurane, we conclude a weak sensitivity only to the specific type of solute-solvent interactions. Within our time-resolution, we surprisingly recover weak but reproducible modulations of the third-order signals that are damped out on the early picosecond timescale.

Background. Elliptical excision is a standard form of treatment for cutaneous neoplasms, but routine pathologic sectioning results in incomplete histologic control of surgical margins. Objective. The objective was to describe a technique of complete histologic margin control for tumors removed by excision as an ellipse. Methods. A retrospective study of 100 consecutive nonmelanoma skin cancers of the head and neck removed using elliptical excisions with complete histologic margin control was performed. The technique is described and depicted in detail. Results. Seventy-one tumors were removed in one excision, and 29 required additional excisions for complete histologic tumor clearance. Linear repairs were used for 93 tumors. Conclusion. Elliptical excision, combined with our technique of complete histologic margin control, provides a simple, efficient, and effective method for surgical removal and repair of nonmelanoma skin cancers and provides an alternative variation of performing Mohs micrographic surgery for selected tumors.

Air-dried apple rings were prepared from ‘Golden Delicious’ apples selected at harvest as less mature and more mature according to the absorption coefficient measured at 670nm by time-resolved reflectance spectroscopy (TRS), stored in air for 5months, and subjected to air-drying with (OSMO) and without (noOSMO) osmodehydration pre-treatment (60% sucrose syrup). Selected rings were submitted to microstructural analysis by X-ray computed tomography (X-CT), to subsurface structure analysis by optical coherence tomography (OCT) and to texture and sound emission analysis by bending–snapping test. Higher crispness index, higher number of sound events and higher average sound pressure level (SPL) characterized the OSMO rings. Total porosity was related to SPLav60, pore fragmentation index to fracturability and specific surface area to the work required to snap the ring. A differentiation of the drying treatments, as well as of the products according to the TRS maturity class at harvest was obtained analyzing by principal component analysis (PCA) microstructure parameters and texture and acoustic parameters. The differences in mechanical and acoustic characteristics between OSMO and noOSMO rings were due to the different subsurface structure as found with OCT analysis.There is an increasing demand of dried crispy fruit as they are considered by consumers healthy, natural and tasty foods. The textural characteristics, exerting a strong effect on crispy and crunchy sensory characteristics, have a great impact at consumption of dried crispy fruit. As their textural characteristics depend on both fruit maturity at processing and processing conditions, food industry is demanding nondestructive techniques which could be used for on-line/off-line sorting of fruit into classes each one more suited for obtaining a specific product. Furthermore, the textural properties of dried foods depend on microstructure, defined as the spatial arrangement of structural components and their interactions. Due to the microscopic complexity, unambiguous methodologies that relate quality to food microstructure do not exist today, in contrast to what already existing for several engineering materials. Hence there is the need of developing methods that measure directly the microstructural properties of dried foods. publisher: Elsevier articletitle: Characterizing the tissue of apple air-dried and osmo-air-dried rings by X-CT and OCT and relationship with ring crispness and fruit maturity at harvest measured by TRS journaltitle: Innovative Food Science & Emerging Technologies articlelink: http://dx.doi.org/10.1016/j.ifset.2013.09.001 content_type: article copyright: Copyright © 2013 Elsevier Ltd. All rights reserved. ispartof: Innovative Food Science & Emerging Technologies vol:24 pages:121-130 status: published

This chapter presents the recent developments in advanced optical methods for exploring food microstructure. The chapter first discusses the basics of light propagation in food and the main limitations of classical approaches (e.g. continuous wave near infrared (NIR), colorimetry) for the measurement of the optical properties of food. It then describes the physical principles, the technological solutions and the advantages of optical coherence tomography, and of space- and time-resolved reflectance spectroscopy. The chapter includes examples of applications and an overview of future prospects. © 2013 Woodhead Publishing Limited All rights reserved.

The two-exciton manifold of a double-wall cylindrical molecular aggregate is studied using a coherent third order optical technique. Experiments reveal the anharmonic character of the exciton bands. Atomistic simulations of the exciton-exciton scattering show that the excitons can be treated as weakly coupled hard-core bosons. The weak coupling stems from the extended exciton delocalization made possible by the nanotube geometry.

In this work we analyze how nuclear coherences modulate diagonal and off-diagonal peaks in two-dimensional electronic spectroscopy. 2D electronic spectra of pinacyanol chloride are measured with 8 fs pulses, which allows coherent excitation of the 1300 cm(-1) vibrational mode. The 2D spectrum reveals both diagonal and off-diagonal peaks related to the vibrational mode. On early time scales, up to 30 fs, coherent dynamics give rise to oscillations in the amplitudes, positions, and shapes of the peaks in the 2D spectrum. We find an anticorrelation between the amplitude and the diagonal width of the two diagonal peaks. The measured data are reproduced with a model incorporating a high frequency mode coupled to an electronic two-level-system. Our results show that these anticorrelated oscillations occur for vibrational wavepackets and not exclusively for electronic coherences as has been assumed previously.

The efficiency of natural light-harvesting complexes relies on delocalization and directed transfer of excitation energy on spatially well-defined arrangements of molecular absorbers. Coherent excitation delocalization and long-range molecular order are also central prerequisites for engineering energy flows in bioinspired devices. Double-wall cylindrical aggregates have emerged as excellent candidates that meet these criteria. So far, the experimental signatures of exciton relaxation in these tubular supramolecules could not be linked to models encompassing their entire spatial structure. On the basis of the power of two-dimensional electronic spectroscopy, we characterize the motion of excitons in the three-fold band structure of the bitubular aggregate C8S3 through temporal, energetic, and spatial attributes. Accounting for intra- as well as interwall electronic interactions in the framework of a Frenkel exciton basis, we employ numerical computations using inhomogeneous and homogeneous microscopic models. The calculations on large but finite structures identify disorder-induced effects, which become increasingly relevant for higher energy states and give insight into the topology of the excited state manifold. Calculations in the infinite homogeneous limit capture the phenomena evidenced in the experimental two-dimensional patterns. Our results provide a basis for understanding recently reported correlated fluctuations of excitonic absorption bands and interband coherences in tubular aggregates.

This is the first in a series of two papers investigating the effect of electron-phonon coupling in two-dimensional Fourier transformed electronic spectroscopy. We present a series of one- and two-dimensional nonlinear spectroscopic techniques for studying a dye molecule in solution. Ultrafast laser pulse excitation of an electronic transition coupled to vibrational modes induces a propagating vibrational wave packet that manifests itself in oscillating signal intensities and line-shapes. For the two-dimensional electronic spectra we can attribute the observed modulations to periodic enhancement and decrement of the relative amplitudes of rephasing and non-rephasing contributions to the total response. Different metrics of the two-dimensional signals are shown to relate to the frequency-frequency correlation function which provides the connection between experimentally accessible observations and the underlying microscopic molecular dynamics. A detailed theory of the time-dependent two-dimensional spectral line-shapes is presented in the accompanying paper [T. Mancal et al., arXiv:1003.xxxx]., 13 pages, 8 figures

Electronic single- and double-quantum coherence spectroscopy (1Q- and 2Q-2D) of β-carotene reveals the energetic position, transition strength and spectral properties of a novel excited state above S2with a transition in the visible spectral region.

Understanding of the nuclear and electronic structure and dynamics of molecular systems has advanced considerably through probing the nonlinear response of molecules to sequences of pulsed electromagnetic fields. The ability to control various degrees of freedom of the excitation pulses-such as duration, sequence, frequency, polarization, and shape-has led to a variety of time-resolved spectroscopic methods. The various techniques that researchers use are commonly classified by their dimensionality, which refers to the number of independently variable time delays between the pulsed fields that induce the signal. Though pico- and femtosecond time-resolved spectroscopies of electronic transitions have come of age, only recently have researchers been able to perform two-dimensional electronic spectroscopy (2D-ES) in the visible frequency regime and correlate transition frequencies that evolve in different time intervals. The two-dimensional correlation plots and their temporal evolution allow one to access spectral information that is not exposed directly in other one-dimensional nonlinear methods. In this Account, we summarize our studies of a series of increasingly complex molecular chromophores. We examine noninteracting dye molecules, a monomer-dimer equilibrium of a prototypical dye molecule, and finally a supramolecular assembly of electronically coupled absorbers. By tracing vibronic signal modulations, differentiating line-broadening mechanisms, analyzing distinctly different relaxation dynamics, determining electronic coupling strengths, and directly following excitation energy transfer pathways, we illustrate how two-dimensional electronic spectroscopy can image physical phenomena that underlie the optical response of a particular system. Although 2D-ES is far from being a "turn-key" method, we expect that experimental progress and potential commercialization of instrumentation will make 2D-ES accessible to a much broader scientific audience, analogous to the development of multidimensional NMR and 2D-IR.

The early stage of molecular excitonics and its quantum-kinetic dynamics in the multiband, bitubular cyanine dye aggregate C(8)O(3) at room temperature are revealed by employing two-dimensional (2D) coherent electronic spectroscopy in the visible spectral region. The sub-20 fs measurements provide a direct look into the details of elementary electronic couplings by spreading spectroscopic transitions into two frequency axes. Correlation spectra of rephasing (k(I) = -k(1) + k(2) + k(3)) and nonrephasing (k(II) = +k(1) - k(2) + k(3)) data in emission (omega(3))-absorption (omega(1)) 2D-frequency space image interband excitons into cross-peak signals and unveil the quantum-dissipative regime of exciton relaxation. Spectral streaking of cross peaks directly reveals interband dephasing and exciton population relaxation on the road to tube-to-tube energy transfer without making recourse to an a priori model. Theory and simulations, based on an effective multilevel scheme and a quantum-dissipative model with experimental pulse envelopes, explain the origin of the cross peaks, reveal the underlying sequences of electronic transitions, recover the streaking patterns of relaxing cross peaks along omega(1), and reconstruct the space-energy pathways of electronic excitation flow.

We present a sequence of two-dimensional electronic spectra of a prototypical cyanine dye, whose spectral properties in aqueous solution are determined by the formation of a monomer–dimer equilibrium. Quantum-chemical methods are utilized to calculate the structure and absorption properties of the two species involved. Our spectroscopic results simultaneously characterize the spectral line-shapes of the two species in terms of underlying dynamic and static disorder, and demonstrate how the two-dimensional technique allows the exploitation of high spectral and temporal resolution in one and the same experiment. The distinctly different spectral relaxation dynamics are quantified in a two-dimensional line-shape analysis, by extracting the time dependent ratios of the diagonal and anti-diagonal peak-widths. Our findings are in line with theoretical considerations, that predict the fluctuational dynamics of an excitonic dimer state to be exchange-narrowed by excitation delocalization.

We trace vibrational wavepacket motion in two-dimensional electronic spectra of a two-level electronic system. The vibronic evolution induces a periodic beating pattern of the diagonal-to-antidiagonal peak width ratio in the absorptive signal part and a periodic tilt of the nodal line in the dispersive signal part. These modulations can be assigned to periodic modulations of the relative amplitudes of rephasing and non-rephasing contributions to the signal.

We investigate molecular excitonics and its quantum-kinetic dynamics in a J-aggregate using 2D electronic spectroscopy. The measurements enable to look into electronic couplings and their intermediate quantum-stochastic trace on the road to population transfer.

background Hematoxylin and Eosin (H&E) is the most common stain used for Mohs frozen sections. Toluidine blue (T-blue) is a metachromatic stain that has been frequently utilized for this purpose. objective To compare the cytologic and stromal staining patterns of each stain for Mohs frozen sections of squamous cell carcinoma (SCC and basal cell carcinoma (BCC), and to identify the advantages and disadvantages of each technique. results T-blue revealed stromal change associated with the presence of BCC and SCC. H&E provided more prominent visibility of individual cell keratinization and necrosis, which are common features seen in SCC. conclusion We found T-blue to be fast and effective in identifying mucopolysaccharides in stroma associated with basal cell carcinoma. For this reason, T-blue is our preferred stain for BCCs, while H&E can provide greater ease of identification of histologic features of SCCs.

Double-quantum coherence two-dimensional (2Q2D) electronic spectroscopy is utilized to probe the dynamic fluctuations of electronic states in a solvated molecule at approximately twice the energy of the ground state bleach transition. The 2Q2D spectrum gives insight into the energetic position and spectral fluctuations (system-bath interaction) of the probed excited states. Combining it with single-quantum two-dimensional (1Q2D) electronic spectroscopy enables one to determine the strength of the excited state absorption transition and the relative detuning of electronic states, as well as the dynamics of the single-quantum coherence. To investigate the correlation of spectral fluctuations in different electronically excited states, we have carried out experiments on a solvated dye (Rhodamine 6G) with 23 fs pulses centered at the maximum of the linear absorption spectrum. The 2Q2D spectrum reveals three peaks of alternating signs with the major negative peak located at higher frequencies along the emission axis compared to the single positive peak. The 1Q2D spectrum, on the other hand, shows a negative peak stemming from excited state absorption at lower frequencies along the emission axis. Analysis of the signal in the homogeneous limit fails to account for this observation as well as the number of peaks in the 2Q2D spectrum. Employing a three-level model in which all time correlations of the third-order response function are accounted for via second-order cumulant expansion gives good agreement with both the 1Q2D and 2Q2D data. Furthermore, the analysis shows that the fluctuations of the probed electronic states are highly correlated, reflecting the modulation by a common nuclear bath and similarities in the nature of the electronic transitions. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3474995]

We present a theory of vibrational modulation of two-dimensional coherent Fourier transformed electronic spectra. Based on an expansion of the system's energy gap correlation function in terms of Huang-Rhys factors, we explain the time-dependent oscillatory behavior of the absorptive and dispersive parts of two-dimensional spectra of a two-level electronic system, weakly coupled to intramolecular vibrational modes. The theory predicts oscillations in the relative amplitudes of the rephasing and non-rephasing parts of the two-dimensional spectra, and enables to analyze time dependent two-dimensional spectra in terms of simple elementary components whose line-shapes are dictated by the interaction of the system with the solvent only. The theory is applicable to both low and high energy (with respect to solvent induced line broadening) vibrations. The results of this paper enable to qualitatively explain experimental observations on low energy vibrations presented in the preceding paper [A. Nemeth et al, arXiv:1003.4174v1] and to predict the time evolution of two-dimensional spectra in ultrafast ultrabroad band experiments on systems with high energy vibrations., Comment: 14 pages, 9 figures

We report a compact, easy to align, and passively phase-stabilized setup for recording two-dimensional (2D) electronic spectra in three different phase-matching directions in the boxcar geometry. Passive phase stabilization is achieved by a diffractive optical element, the use of refractive optics for introducing pulse delays, and the use of common optics for all pulses. Representative 2D spectra correlating single- and double-quantum coherences in a molecular aggregate are presented.

Electronic two-dimensional spectroscopy with sub-7 fs resolution with the aid of simulations and quantum chemistry reveals the time scale and underlying dynamics of electron-phonon coupling, internal vibrational redistribution, and double quantum resonances in solvated Zinc-Phthalocyanine.