Properly designed organic molecules where a π‐conjugated bridge is end‐capped by an electron‐donor and electron‐withdrawing group (push–pull chromophores) can show, under specific conditions, frequency‐upconverted lasing emission. Materials based on these dyes are therefore able to convert the emission of a cheap and easily available infrared (IR) laser (e.g., 800 nm radiation) into more useful visible (vis) laser emission via a two‐photon absorption induced fluorescence phenomenon. The design of the molecular structure, the substituent effect, and modulation of the electronic and geometric parameters can be used in order to optimize and tune frequency emission and conversion efficiency. Examples of some of the best dyes reported to‐date and organic design strategies employed are discussed in this article. 相似文献
Summary: A customized instrument has been developed as part of multidisciplinary research work relating to the development of a biodegradable vascular scaffold. This instrument aims to measure the mechanical properties of elastic and viscoelastic thin membranes with tissue engineering applications. Uniform and omni‐directional pressure is applied on the whole membrane which is uniformly clamped and submerged into a liquid medium. The mechanical testing described in this study is focused on the stress‐strain curves of polycaprolactone (PCL) films after different treatments. The influence of Dulbecco's modified Eagle's culture medium, L929 fibroblast culture, NaOH treatment and film thickness on the mechanical properties of PCL films was evaluated after different times. These studies show that the PCL degradation process is influenced by immersion in the culture medium, inducing an increment in the slope of the pressure‐dilation curve which is indicative of an increase in the polymer stiffness. On the other hand, long NaOH treatments make PCL films have more flexible behavior.
A computerized version of the instrument: (1) Electrical compressor; (2) Filter; (3) Voltage‐pressure converter; (5) Pressure sensor; (6) Differential pressure sensor; (7–8) Main and auxiliary pipettes; (9) Printed circuit board; (10) Personal computer. 相似文献
Myocardial infarction (MI) is one of the leading causes of heart-related deaths worldwide. Following MI, the hypoxic microenvironment triggers apoptosis, disrupts the extracellular matrix and forms a non-functional scar that leads towards adverse left ventricular (LV) remodelling. If left untreated this eventually leads to heart failure. Besides extensive advancement in medical therapy, complete functional recovery is never accomplished, as the heart possesses limited regenerative ability. In recent decades, the focus has shifted towards tissue engineering and regenerative strategies that provide an attractive option to improve cardiac regeneration, limit adverse LV remodelling and restore function in an infarcted heart. Acellular scaffolds possess attractive features that have made them a promising therapeutic candidate. Their application in infarcted areas has been shown to improve LV remodelling and enhance functional recovery in post-MI hearts. This review will summarise the updates on acellular scaffolds developed and tested in pre-clinical and clinical scenarios in the past five years with a focus on their ability to overcome damage caused by MI. It will also describe how acellular scaffolds alone or in combination with biomolecules have been employed for MI treatment. A better understanding of acellular scaffolds potentialities may guide the development of customised and optimised therapeutic strategies for MI treatment. 相似文献
We have isolated a cDNA clone encoding eIF4A from Schizosaccharomyces pombe. The deduced protein sequence is similar in length and sequence to other eIF4A proteins and exhibits highest similarity with the mammalian eIF4A protein. Hybridization with genomic DNA reveals two eIF4A genes located on two different chromosomes. This sequence has been deposited in the EMBL Data Library under Accession Number X80796. 相似文献
BACKGROUND: The new microemulsion formulation of cyclosporine (CsA-ME) displays more consistent pharmacokinetic properties than the original formulation and may allow successful implementation of an abbreviated area-under-the-curve (AUC) strategy. METHODS: Here we compared two limited sampling strategies in order to define the one that best predicts AUC after CsA-ME in 51 renal transplant recipients with stable renal function. Pharmacokinetics were based on analysis of blood samples collected over 12 hours after drug administration by high-performance liquid chromatography (HPLC). Predicted AUC was estimated by using a three-point (0, 1 and 3 hr) or a two-point (2 and 6 hr or 0 and 2 hr) sampling strategy. RESULTS: A simplified strategy with three time points of blood collection at 0, 1, and 3 hours after CsA-ME allowed adequate and accurate prediction of the daily exposure to CsA. AUC prediction with two-point sampling at 2 and 6 hours was less good with a very large error in prediction (only 59% of the estimated AUC were within the accepted range). This limitation was even more evident when the 0 and 2 hour time points were examined, in which only 51% of AUC estimates were included in the accepted range of variation (-10 to 10%). CONCLUSIONS: A limited strategy of three-point sampling taken early after dosing allows an excellent and perfectly reliable prediction of the actual AUC. 相似文献
This paper describes a technique for automating the detection and classification of non-functional requirements related to
properties such as security, performance, and usability. Early detection of non-functional requirements enables them to be
incorporated into the initial architectural design instead of being refactored in at a later date. The approach is used to
detect and classify stakeholders’ quality concerns across requirements specifications containing scattered and non-categorized
requirements, and also across freeform documents such as meeting minutes, interview notes, and memos. This paper first describes
the classification algorithm and then evaluates its effectiveness through reporting a series of experiments based on 30 requirements
specifications developed as term projects by MS students at DePaul University. A new and iterative approach is then introduced
for training or retraining a classifier to detect and classify non-functional requirements (NFR) in datasets dissimilar to
the initial training sets. This approach is evaluated against a large free-form requirements document obtained from Siemens
Logistics and Automotive Organization. Although to the NFR classifier is unable to detect all of the NFRs, it is useful for
supporting an analyst in the error-prone task of manually discovering NFRs, and furthermore can be used to quickly analyse
large and complex documents in order to search for NFRs. 相似文献