Photodynamic therapy using intravenous delta-aminolaevulinic acid-induced protoporphyrin IX sensitisation in experimental hepatic tumours in rats.

The efficacy of photodynamic therapy (PDT) using delta-aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) sensitisation and laser light at 635 nm was investigated in the treatment of experimental hepatic tumours. The model of liver tumours was induced either by local inoculation or by administration of tumour cells through the portal vein in rats. ALA at a dose of 60 mg kg(-1) b.w. was intravenously administered 60 min before PDT. PpIX accumulation in tumour, normal liver and abdominal wall muscle was detected by means of laser-induced fluorescence (LIF). Laser Doppler imaging (LDI) was used to determine changes in the superficial blood flow in connection with PDT. Histopathological examinations were performed to evaluate the PDT effects on the tumour and the surrounding liver tissue, including pathological features in the microvascular system. The accumulation of PpIX, as monitored by LIF, showed high fluorescence intensities at about 635 nm in both the hepatic tumour tissue and normal liver and low values in the abdominal wall. LDI demonstrated that the blood flow in the treated tumour and its surrounding normal liver tissue decreased immediately after the PDT, indicating an effect on the vascular system. A large number of thrombi in the irradiated tumour were found microscopically 3 h after the PDT. The tumour growth rate showed a marked decrease when evaluated 3 and 6 days after the treatment. These results show that the ALA-PDT is effective in the inhibition of growth of experimental hepatic tumours

Early Citizen Science Action in Ethnobotany: The Case of the Folk Medicine Collection of Dr. Mihkel Ostrov in the Territory of Present-Day Estonia, 1891–1893

Presently, collecting data through citizen science (CS) is increasingly being used in botanical, zoological and other studies. However, until now, ethnobotanical studies have underused CS data collection methods. This study analyses the results of the appeal organized by the physician Dr. Mihkel Ostrov (1863–1940), which can be considered the first-ever internationally known systematic example of ethnopharmacological data collection involving citizens. We aim to understand what factors enhanced or diminished the success of the collaboration between Ostrov and the citizens of that time. The reliability of Ostrov’s collection was enhanced by the herbarium specimens (now missing) used in the identification of vernacular names. The collection describes the use of 65 species from 27 genera. The timing of its collection coincided with not only a national awakening and recently obtained high level of literacy but also the activation of civil society, people’s awareness of the need to collect folklore, the voluntary willingness of newspapers to provide publishing space and later to collect data, and the use of a survey method focusing on a narrow topic. While Ostrov’s only means of communication with the public was through newspapers, today, with electronic options, social media can also be used

Sub-Doppler spectroscopy of Rb atoms in a sub-micron vapor cell in the presence of a magnetic field

We report the first use of an extremely thin vapor cell (thickness ~ 400 nm) to study the magnetic-field dependence of laser-induced-fluorescence excitation spectra of alkali atoms. This thin cell allows for sub-Doppler resolution without the complexity of atomic beam or laser cooling techniques. This technique is used to study the laser-induced-fluorescence excitation spectra of Rb in a 50 G magnetic field. At this field strength the electronic angular momentum J and nuclear angular momentum I are only partially decoupled. As a result of the mixing of wavefunctions of different hyperfine states, we observe a nonlinear Zeeman effect for each sublevel, a substantial modification of the transition probabilities between different magnetic sublevels, and the appearance of transitions that are strictly forbidden in the absence of the magnetic field. For the case of right- and left- handed circularly polarized laser excitation, the fluorescence spectra differs qualitatively. Well pronounced magnetic field induced circular dichroism is observed. These observations are explained with a standard approach that describes the partial decoupling of I and J states

Observation of narrow Autler-Townes components in the resonant response of a dense atomic gas

We have experimentally studied the reflection of a weak probe beam from a dense atomic potassium vapor in the presence of a strong laser field tuned to the atomic resonance transition. We have observed an Autler-Townes doublet under hitherto unexplored conditions, namely that the Rabi frequency induced by the strong laser field is much smaller than the self-broadened width of the resonance transition of the unexcited vapor. We attribute our observation to a reduction of the atomic decoherence by the strong drive field. We present a theoretical model of nonlinear processes in a dense atomic gas to explain the observed results

Corporate governance performance ratings with machine learning

We use machine learning with a cross-sectional research design to predict governance controversies and to develop a measure of the governance component of the environmental, social, governance (ESG) metrics. Based on comprehensive governance data from 2,517 companies over a period of 10 years and investigating nine machine-learning algorithms, we find that governance controversies can be predicted with high predictive performance. Our proposed governance rating methodology has two unique advantages compared with traditional ESG ratings: it rates companies' compliance with governance responsibilities and it has predictive validity. Our study demonstrates a solution to what is likely the greatest challenge for the finance industry today: how to assess a company's sustainability with validity and accuracy. Prior to this study, the ESG rating industry and the literature have not provided evidence that widely adopted governance ratings are valid. This study describes the only methodology for developing governance performance ratings based on companies' compliance with governance responsibilities and for which there is evidence of predictive validity

Stability and power optimality in time-periodic flapping wing structures

This paper investigates the nonlinear dynamics of a vehicle with two flexible flapping wings. The body dynamics and the wings\u27 deformation are monolithically grouped into a single system of equations, with aerodynamics accounted for by a quasi-steady blade element method. A periodic shooting method is then used to locate closed orbits of this non-autonomous system, and Floquet multipliers assess the linearized stability about the nonlinear orbit. This framework is then exposed to a gradient based optimizer, in order to quantify the role of wing planform variables, wing structure variables, and kinematic actuation variables in obtaining vehicles with superior open-loop stability characteristics, and/or low-power requirements

Prevalence of psychiatric disorders in infertile women and men undergoing in vitro fertilization treatment

BACKGROUND: This study was undertaken to determine the prevalence of psychiatric disorders in infertile women and men undergoing in vitro fertilization (IVF) treatment. METHODS: Participants were 1090 consecutive women and men, 545 couples, attending a fertility clinic in Sweden during a two-year period. The Primary Care Evaluation of Mental Disorders (PRIME-MD), based on the Diagnostic and Statistical Manual of Mental Disorders, 4th edn (DSM-IV), was used as the diagnostic tool for evaluating mood and anxiety disorders. RESULTS: Overall, 862 (79.1%) subjects filled in the PRIME-MD patient questionnaire. Any psychiatric diagnosis was present in 30.8 % of females and in 10.2 % of males in the study sample. Any mood disorder was present in 26.2 % of females and 9.2% of males. Major depression was the most common mood disorder, prevalent in 10.9 % of females and 5.1 % of males. Any anxiety disorder was encountered in 14.8 % of females and 4.9 % males. Only 21 % of the subjects with a psychiatric disorder according to DSM-IV received some form of treatment. CONCLUSIONS: Mood disorders are common in both women and men undergoing IVF treatment. The majority of subjects with a psychiatric disorder were undiagnosed and untreated