Search results for "work"
showing 10 items of 14511 documents
Growing and Shaping Metal–Organic Framework Single Crystals at the Millimeter Scale
2020
Controlling and understanding the mechanisms that harness crystallization processes is of utmost importance in contemporary materials science and, in particular, in the realm of reticular solids where it still remains a great challenge. In this work, we show that environments mimicking microgravity conditions can harness the size and shape of functional biogenic crystals such as peptide-based metal–organic frameworks (MOFs). In particular, we demonstrate formation of the largest single crystals with controlled nonequilibrium shapes of peptide-based MOFs reported to date (e.g., those featuring curved crystal habits), as opposed to the typical polyhedral microcrystals obtained under bul…
A Wavy Two-Dimensional Covalent Organic Framework from Core- Twisted Polycyclic Aromatic Hydrocarbons
2019
A high degree of crystallinity is an essential aspect in two-dimensional covalent organic frameworks, as many properties depend strongly on the structural arrangement of the different layers and their constituents. We introduce herein a new design strategy based on core-twisted polycyclic aromatic hydrocarbon as rigid nodes that give rise to a two-dimensional covalent organic framework with a wavy honeycomb (chairlike) lattice. The concave–convex self-complementarity of the wavy two-dimensional lattice guides the stacking of framework layers into a highly stable and ordered covalent organic framework that allows a full 3D analysis by transmission electron microscopy revealing its chairlike …
Toward Engineering Chiral Rodlike Metal-Organic Frameworks with Rare Topologies.
2018
The establishment of novel design strategies to target chiral rodlike MOFs, elusively faced until now, is one of the most straightforward manners to widen the scope of MOFs. Here we describe our last advances on the application of the metalloligand design strategy toward the development of efficient routes to obtain chiral rodlike MOFs. To this end, we have used as precursor an enantiopure homochiral hexanuclear wheel (1), derived from the amino acid d-valine, which, after a supramolecular reorganization into a one-dimensional homochiral chain-with the same configuration as 1-led to the formation of a homochiral rodlike MOF (2) exhibiting rare etd topology.
Application of infrared spectroscopy as Process Analytics Technology (PAT) approach in biodiesel production process utilizing Multivariate Curve Reso…
2019
Abstract Process Analytical Technology means at-line collection of analytical information from the process when the reaction is in progress. Obtained information enables process engineers to better control the Critical Process Parameters and direct the reaction to desirable routs. Near-infrared spectroscopy due to its analytical features, as well as the high capability of automation, versatile sampling and spectral acquisition methods is a useful tool in process monitoring when coupled to chemometrics. The Multiple Scatter Correction preprocessing technique and Alternative Least Square method can extract spectral and concentration information of a reaction mixture simultaneously, were emplo…
Artificial neural network for quantitative determination of total protein in yogurt by infrared spectrometry
2009
Abstract A method has been introduced for quantitative determination of protein content in yogurt samples based on the characteristic absorbance of protein in 1800–1500 cm− 1 spectral region by mid-FTIR spectroscopy and chemometrics. Successive Projection Algorithm (SPA) wavelength selection procedure, coupled with feed forward Back-Propagation Artificial Neural Network (BP-ANN) model was the benefited chemometric technique. Relative Error of Prediction (REP) in BP-ANN and SPA-BP-ANN methods for training set was 7.25 and 3.70 respectively. Considering the complexity of the sample, the ANN model was found to be reliable, while the proposed method is rapid and simple, without any sample prepa…
Measurements of Tumor Blood Flow Using Intraperitoneal Deuterium and 2H-NMR Spectroscopy
1992
Tumors usually have a sparse, disorganized, and inefficient vascular network that leaves a large fraction of the tumor cells in an oxygen deprived and hostile metabolic microenvironment. Hence tumor blood flow, or more correctly nutritive perfusion, has important interactions with treatment efficacy. For example, hypoxic tumor cells, which occur in tumors with low blood flow, are less susceptible to radiation and are probably responsible for most radiation treatment failures (Adams, 1981). Similarly, cytotoxic drug delivery could be predicted by blood flow measurements, with clear implications regarding the expected success of chemotherapy. Thus, the ability to conveniently measure tumor bl…
Schools That ‘Open Doors’ to Prevent Child Abuse in Confinement by COVID-19
2020
Background: Due to the expected increase in child abuse during the period of COVID-19 confinement, it is essential that social researchers and other professionals work together very quickly to provide alternatives that protect children. To respond to this extremely urgent demand, evidence-based actions are presented that are being carried out in nine schools in the autonomous communities of Valencia and Murcia, Spain, during the confinement with the goal of “opening doors” to foster supportive relationships and a safe environment to prevent child abuse. Methods: The research was conducted through the inclusion of teachers who are implementing these actions in dialogue with the researchers t…
Child protection in Europe: development of an international cross-comparison model to inform national policies and practices
2015
We report a five-nations project in comparative child protection to provide recommendations on policy and practice to inform the redevelopment of the Swiss child protection system. The Swiss Federal Government and the Optimus and Oak Foundations commissioned the project—collective title: Association Programme National pour la Protection de l'Enfant. We identify the historical developmental trajectories of child protection systems together with common drivers: the evidential basis for the prevalence and effects of child abuse, the co-joining of social and economic policies and practices to promote early investment in children, the influence of children's rights and comparative international …
Childhood Adversities and Adult Headache in Poland and Germany.
2015
Objective Various childhood adversities have been found to be associated with chronic pain in adulthood. However, associations were moderate in most studies, i.e. odds ratios (OR) were between one and two. Method An internet survey was performed in 508 Polish and 500 German subjects. A total of 19 childhood adversities were selected and their associations with headaches explored. Age, gender and country were included as potential confounders, as well as their two-way interaction with the risk factors. Results Two strong risk factors were identified. (1) A combined score for physical and emotional neglect showed an odds ratio (OR) of 2.78 (p < .002) to the frequency of headache in adulthood …
Walking Children Through a Minefield: How Professionals Experience Exploring Adverse Childhood Experiences
2017
Understanding the challenges of professionals in addressing child adversity is key to improving the detection, protection, and care of exposed children. We aimed to synthesize findings from qualitative studies of professionals’ lived experience of addressing child adversity. Through a systematic search, we identified eight qualitative studies and synthesized them using metaethnography. We generated three themes, “feeling inadequate,” “fear of making it worse,” and “facing evil,” and one overarching metaphor, “walking children through a minefield.” The professionals felt that they lacked the means necessary to explore child adversity, that they were apprehensive of worsening the child’s situ…