Cation delocalization and photo-isomerization enhance the uncaging quantum yield of a photocleavable protecting group

Photocleavable protecting groups (PPGs) enable the light-induced, spatiotemporal control over the release of a payload of interest. Two fundamental challenges in the design of new, effective PPGs are increasing the quantum yield (QY) of photolysis and red-shifting the absorption spectrum. Here we describe the combination of two photochemical strategies for PPG optimization in one molecule, resulting in significant improvements in both these crucial parameters. Furthermore, we for the first time identify the process of photo-isomerization to strongly influence the QY of photolysis of a PPG and identify the cis-isomer as the superior PPG. </p

Cation delocalization and photo-isomerization enhance the uncaging quantum yield of a photocleavable protecting group

Photocleavable protecting groups (PPGs) enable the light-induced, spatiotemporal control over the release of a payload of interest. Two fundamental challenges in the design of new, effective PPGs are increasing the quantum yield (QY) of photolysis and red-shifting the absorption spectrum. Here we describe the combination of two photochemical strategies for PPG optimization in one molecule, resulting in significant improvements in both these crucial parameters. Furthermore, we for the first time identify the process of photo-isomerization to strongly influence the QY of photolysis of a PPG and identify the cis-isomer as the superior PPG. </p

Valid measurement of DSM-5 persistent complex bereavement disorder and DSM-5-TR and ICD-11 prolonged grief disorder:The Traumatic Grief Inventory-Self Report Plus (TGI-SR+)

Introduction: When grief reactions after bereavement are so intense that they impair daily functioning, a diagnosis of disturbed grief may apply. Slightly differing criteria-sets for disturbed grief are included in the ICD-11, the DSM-5, and its forthcoming text revision, DSM-5-TR. We examined psychometric properties of a new self-report measure, the 22-item Traumatic Grief Inventory-Self Report Plus (TGI-SR+), that assesses these criteria sets for Persistent Complex Bereavement Disorder (PCBD) as per DSM-5, and Prolonged Grief Disorder (PGD) as defined in ICD-11 and DSM-5-TR. Material and methods: We examined the: i) factor structure, ii) internal consistency, iii) temporal stability, iv) convergent validity, v) known-groups validity, vi) probable caseness, and vii) optimal clinical cut-off scores in two Dutch bereaved samples. Sample 1 consisted of 278 adults, bereaved by various causes. Sample 2 included 270 adults who lost loved ones in a traffic accident. Results: We found support for a 3-factor PCBD model, 1-factor DSM-5-TR model, and 1-factor ICD-11 PGD model. The DSM-5 PCBD, DSM-5-TR PGD, and ICD-11 PGD items demonstrated good internal consistency and temporal stability. Associations between disturbed grief symptoms and posttraumatic stress and depression levels supported convergent validity. Associations between demographic/loss-related variables and disturbed grief symptoms supported known-groups validity. Optimal clinical cut-offs for the TGI-SR+ total score were ≥ 75, ≥71, and ≥ 75 for probable caseness of DSM-5 PCBD, DSM-5-TR PGD, and ICD-11 PGD, respectively. Discussion: While replication of our findings in diverse bereaved samples is needed, we conclude that the TGI-SR+ is a reliable and valid measure to assess symptoms of DSM-5 PCBD, DSM-5-TR PGD, and ICD-11 PGD

Static avalanches and Giant stress fluctuations in Silos

We propose a simple model for arch formation in silos. We show that small pertubations (such as the thermal expansion of the beads) may lead to giant stress fluctuations on the bottom plate of the silo. The relative amplitude $\Delta$ of these fluctuations are found to be power-law distributed, as $\Delta^{-\tau}$, $\tau \simeq 1.0$. These fluctuations are related to large scale `static avalanches', which correspond to long-range redistributions of stress paths within the silo.Comment: 10 pages, 4 figures.p

Study of shock waves generation, hot electron production and role of parametric instabilities in an intensity regime relevant for the shock ignition

We present experimental results at intensities relevant to Shock Ignition obtained at the sub-ns Prague Asterix Laser System in 2012 . We studied shock waves produced by laser-matter interaction in presence of a pre-plasma. We used a first beam at 1ω (1315 nm) at 7 × 10 13 W/cm 2 to create a pre-plasma on the front side of the target and a second at 3ω (438 nm) at ∼ 10 16 W/cm 2 to create the shock wave. Multilayer targets composed of 25 (or 40 μm) of plastic (doped with Cl), 5 μm of Cu (for Kα diagnostics) and 20 μm of Al for shock measurement were used. We used X-ray spectroscopy of Cl to evaluate the plasma temperature, Kα imaging and spectroscopy to evaluate spatial and spectral properties of the fast electrons and a streak camera for shock breakout measurements. Parametric instabilities (Stimulated Raman Scattering, Stimulated Brillouin Scattering and Two Plasmon Decay) were studied by collecting the back scattered light and analysing its spectrum. Back scattered energy was measured with calorimeters. To evaluate the maximum pressure reached in our experiment we performed hydro simulations with CHIC and DUED codes. The maximum shock pressure generated in our experiment at the front side of the target during laser-interaction is 90 Mbar. The conversion efficiency into hot electrons was estimated to be of the order of ∼ 0.1% and their mean energy in the order ∼50 keV. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distributio