Generation of coherent terahertz pulses in Ruby at room temperature

We have shown that a coherently driven solid state medium can potentially produce strong controllable short pulses of THz radiation. The high efficiency of the technique is based on excitation of maximal THz coherence by applying resonant optical pulses to the medium. The excited coherence in the medium is connected to macroscopic polarization coupled to THz radiation. We have performed detailed simulations by solving the coupled density matrix and Maxwell equations. By using a simple $V$-type energy scheme for ruby, we have demonstrated that the energy of generated THz pulses ranges from hundreds of pico-Joules to nano-Joules at room temperature and micro-Joules at liquid helium temperature, with pulse durations from picoseconds to tens of nanoseconds. We have also suggested a coherent ruby source that lases on two optical wavelengths and simultaneously generates THz radiation. We discussed also possibilities of extension of the technique to different solid-state materials

Refining a model of collaborative care for people with a diagnosis of bipolar, schizophrenia or other psychoses in England: a qualitative formative evaluation

This is the final version. Available on open access from BMC via the DOI in this recordAvailability of data and materials: Transcripts will not be shared in their entirety to protect the anonymity of service users and care partners delivering the intervention. However, requests for excerpts of the data will be considered on an individual basis. Please contact the corresponding author.Background Many people diagnosed with schizophrenia, bipolar or other psychoses in England receive the majority of their healthcare from primary care. Primary care practitioners may not be well equipped to meet their needs and there is often poor communication with secondary care. Collaborative care is a promising alternative model but has not been trialled specifically with this service user group in England. Collaborative care for other mental health conditions has not been widely implemented despite evidence of its effectiveness. We carried out a formative evaluation of the PARTNERS model of collaborative care, with the aim of establishing barriers and facilitators to delivery, identifying implementation support requirements and testing the initial programme theory. Methods The PARTNERS intervention was delivered on a small scale in three sites. Qualitative data was collected from primary and secondary care practitioners, service users and family carers, using semi-structured interviews, session recordings and tape-assisted recall. Deductive and inductive thematic analysis was carried out; themes were compared to the programme theory and used to inform an implementation support strategy. Results Key components of the intervention that were not consistently delivered as intended were: interaction with primary care teams, the use of coaching, and supervision. Barriers and facilitators identified were related to service commitment, care partner skills, supervisor understanding and service user motivation. An implementation support strategy was developed, with researcher facilitation of communication and supervision and additional training for practitioners. Some components of the intervention were not experienced as intended; this appeared to reflect difficulties with operationalising the intervention. Analysis of data relating to the intended outcomes of the intervention indicated that the mechanisms proposed in the programme theory had operated as expected. Conclusions Additional implementation support is likely to be required for the PARTNERS model to be delivered; the effectiveness of such support may be affected by practitioner and service user readiness to change. There is also a need to test the programme theory more fully. These issues will be addressed in the process evaluation of our full trial.National Institute for Health Research (NIHR

A structural comparison of human serum transferrin and human lactoferrin

The transferrins are a family of proteins that bind free iron in the blood and bodily fluids. Serum transferrins function to deliver iron to cells via a receptor-mediated endocytotic process as well as to remove toxic free iron from the blood and to provide an anti-bacterial, low-iron environment. Lactoferrins (found in bodily secretions such as milk) are only known to have an anti-bacterial function, via their ability to tightly bind free iron even at low pH, and have no known transport function. Though these proteins keep the level of free iron low, pathogenic bacteria are able to thrive by obtaining iron from their host via expression of outer membrane proteins that can bind to and remove iron from host proteins, including both serum transferrin and lactoferrin. Furthermore, even though human serum transferrin and lactoferrin are quite similar in sequence and structure, and coordinate iron in the same manner, they differ in their affinities for iron as well as their receptor binding properties: the human transferrin receptor only binds serum transferrin, and two distinct bacterial transport systems are used to capture iron from serum transferrin and lactoferrin. Comparison of the recently solved crystal structure of iron-free human serum transferrin to that of human lactoferrin provides insight into these differences

Resonance trapping of monochromatically generated 29 CM-1 phonons in strongly excited ruby crystals

We report on a study of the resonance trapping of monochromatically generated 29 cm-1 phonons in strongly excited ruby crystals. By use of a pulsed far infrared laser we generated, in homogeneously excited crystals, monochromatic phonon pulses and studied the trapping and decay of these phonons. We found that the trapping time increased with the square root of the concentration of excited Cr3+ ions and that it depended on the crystal dimension. We show, furthermore, that the trapping time depends on crystal quality and that it can be strongly influenced by inhomogeneous stress and by X-ray irradiation. We used a model of spectral-spatial phonon diffusion for a description of the experimental results

Resonanzeinfang monochromatisch erzeugter 29CM"-"1 Phononen in optisch stark angeregtem Rubin

TIB Hannover: DR 4523 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Homogeneously broadened far-infrared absorption line due to the Ebar-]2abar transition of excited chromium ions in ruby

By use of far-infrared laser spectroscopy, we have found that for a high-quality ruby crystal at low temperature, the absorption line due to the electronic transition between the excited states Image and Image ions is previous termhomogeneouslynext term broadened. From the linewidth (0.011 cm-1) the lifetime of the 2Image level against emission of 29 cm-1 phonons is obtained

Concentration dependence of the Ebar-]2abar far-infrared transition of excited chromium ions in ruby

The absorption due to electronic transitions between the excited Image (2E) state and the 2Image (2E) state of Cr3+ ions in optically pumped ruby is studied by Zeeman spectroscopy with a far-infrared laser. We find that the linewidth and the oscillator strength of the Image → 2Image transition increase quadratically with the chromium concentration for ruby crystals containing more than 0.1 wt.% Cr2O3

Mars, a molecule archive suite for reproducible analysis and reporting of single-molecule properties from bioimages

The rapid development of new imaging approaches is generating larger and more complex datasets, revealing the time evolution of individual cells and biomolecules. Single-molecule techniques, in particular, provide access to rare intermediates in complex, multistage molecular pathways. However, few standards exist for processing these information-rich datasets, posing challenges for wider dissemination. Here, we present Mars, an open-source platform for storing and processing image-derived properties of biomolecules. Mars provides Fiji/ImageJ2 commands written in Java for common single-molecule analysis tasks using a Molecule Archive architecture that is easily adapted to complex, multistep analysis workflows. Three diverse workflows involving molecule tracking, multichannel fluorescence imaging, and force spectroscopy, demonstrate the range of analysis applications. A comprehensive graphical user interface written in JavaFX enhances biomolecule feature exploration by providing charting, tagging, region highlighting, scriptable dashboards, and interactive image views. The interoperability of ImageJ2 ensures Molecule Archives can easily be opened in multiple environments, including those written in Python using PyImageJ, for interactive scripting and visualization. Mars provides a flexible solution for reproducible analysis of image-derived properties, facilitating the discovery and quantitative classification of new biological phenomena with an open data format accessible to everyone