Multi-photon attenuation-compensated light-sheet fluorescence microscopy

We thank the UK Engineering and Physical Sciences Research Council for funding (grants EP/P030017/1 and EP/R004854/1), the European Union’s Horizon 2020 Framework Programme (H2020) (675512, BE-OPTICAL), the Danish Council for Independent Research (DFF FTP grant 7017-00021), and the Otto Mønsted Foundation (grant 19-70-0109).Attenuation of optical fields owing to scattering and absorption limits the penetration depth for imaging. Whilst aberration correction may be used, this is difficult to implement over a large field-of-view in heterogeneous tissue. Attenuation-compensation allows tailoring of the maximum lobe of a propagation-invariant light field and promises an increase in depth penetration for imaging. Here we show this promising approach may be implemented in multi-photon (two-photon) light-sheet fluorescence microscopy and, furthermore, can be achieved in a facile manner utilizing a graded neutral density filter, circumventing the need for complex beam shaping apparatus. A “gold standard” system utilizing a spatial light modulator for beam shaping is used to benchmark our implementation. The approach will open up enhanced depth penetration in light-sheet imaging to a wide range of end users.Publisher PDFPeer reviewe

Epstein-Barr Virus Infection and Sporadic Breast Cancer Risk: A Meta-Analysis

BACKGROUND: A large number of epidemiological studies have evaluated the association between Epstein-Barr virus infection and breast carcinoma risk but results have been inconsistent. METHODOLOGY: Research using the polymerase chain reaction technique for detecting the Epstein-Barr virus was selected; 24 studies and 1535 cases were reviewed. Information on the study populations, sample types, publication calendar period and histological types of breast carcinoma were collected. An unconditional logistic regression model was used to analyze potential parameters related to the Epstein-Barr virus prevalence. A Kappa test was used to evaluate the consistency in detecting different Epstein-Barr virus DNA regions. Nine studies that included control groups and 1045 breast cancer cases were adopted in this meta-analysis. CONCLUSIONS: We found that 29.32% of the patients with breast carcinoma were infected with the Epstein-Barr virus. The prevalence of Epstein-Barr was highest in Asia (35.25%) and lowest in the USA (18.27%). Statistical analysis revealed a trend that showed lobular breast carcinoma might have the strongest association with Epstein-Barr virus infection. This meta-analysis showed a significant increase in breast malignancy risk in patients testing positive for the Epstein-Barr virus (OR = 6.29, 95% CI = 2.13-18.59). This result suggests that an Epstein-Barr virus infection is statistically associated with increased breast carcinoma risk

The activity of digestive enzymes during the molting stages of the arched swimming Callinectes arcuatus Ordway, 1863 (Crustacea : Decapoda : Portunidae)

Entrada sobre el poeta Juan Carlos Friebe Olmedo (Granada, 1968) incluida en el DICCIONARIO DE AUTORES GRANADINOS de la Academia de Buenas Letras de Granada, publicado en línea en la website oficial de la citada academia

Coincidence timing of femtosecond optical pulses in an X-ray free electron laser

Femtosecond resolution pump-probe experiments are now routinely carried out at X-ray Free Electron Lasers, enabled by the development of cross-correlation “time-tools” which correct the picosecond-level jitter between the optical and X-ray pulses. These tools provide very accurate, <10 fs, measurement of the relative arrival time, but do not provide a measure of the absolute coincidence time in the interaction. Cross-correlation experiments using transient reflectivity in a crystal are commonly used for this purpose, and to date no quantitative analysis of the accuracy or stability of absolute coincidence time determination has been performed. We have performed a quantitative analysis of coincidence timing at the SACLA facility through a cross-correlation of 100 6 10 fs, 400 nm optical pulses with 7 fs, 10.5 keV X-ray pulses via transient reflectivity in a cerium-doped yttrium aluminum garnet crystal. We have modelled and fit the transient reflectivity, which required a convolution with a 226 6 12 fs uncertainty that was believed to be dominated by X-ray and laser intensity fluctuations, or assuming an extinction depth of 13.3 lm greater than the literature value of 66.7 lm. Despite this, we are able to determine the absolute coincidence time to an accuracy of 30 fs. We discuss the physical contributions to the uncertainty of coincidence time determination, which may include an uncharacterised offset delay in the development of transient reflectivity, including cascading Auger decays, secondary ionisation and cooling processes. Additionally, we present measurements of the intrinsic short-term and long-term drifts between the X-rays and the optical laser timing from time-tool analysis, which is dominated by a thermal expansion of the 25 m optical path between tool and the interaction region, seen to be 60 fs over a period of 5 h

Environmental factors structuring polychaete communities in shallow rocky habitats: role of physical stress versus habitat complexity.

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