High-Throughput Nonlinear Optical Microscopy

High-resolution microscopy methods based on different nonlinear optical (NLO) contrast mechanisms are finding numerous applications in biology and medicine. While the basic implementations of these microscopy methods are relatively mature, an important direction of continuing technological innovation lies in improving the throughput of these systems. Throughput improvement is expected to be important for studying fast kinetic processes, for enabling clinical diagnosis and treatment, and for extending the field of image informatics. This review will provide an overview of the fundamental limitations on NLO microscopy throughput. We will further cover several important classes of high-throughput NLO microscope designs with discussions on their strengths and weaknesses and their key biomedical applications. Finally, this review will close with a perspective of potential future technological improvements in this field.National Institutes of Health (U.S.) (9P41EB015871-26A1)National Institutes of Health (U.S.) (R01-EX017656)National Institutes of Health (U.S.) (5 R01 NS051320)National Institutes of Health (U.S.) (4R44EB012415-02)National Science Foundation (U.S.) (CBET-0939511)Singapore-MIT AllianceSkolkovo Institute of Science and TechnologySingapore. National Research Foundation (Singapore-MIT Alliance for Research and Technology)Wellcome Trust (London, England) (Massachusetts Institute of Technology. Postdoctoral Fellowship 093831/Z/10/Z

Experience With Dielectric Response Measurements On Oil-Paper Insulated Cables

Deterioration of the underground power cables insulation has been established to be caused by electrical, thermal and environmental stresses. With the degradation of dielectric strength of the insulation, the underground cables will not be able to function optimally or as planned. As a supplement to the existing dissipation factor and other conventional cable diagnostic measurements, the Decay Voltage (DV) and the Return Voltage (RV) measurement technologies are currently being proposed for nondestructive diagnosis of cable insulation. The main purpose of this paper is to present results from laboratory measurements of DV, RV and Polarisation and Depolarisation Current (PDC) on a number of samples of oil-impregnated paper insulated cables. Comparison of these results has also been made with the conventional dissipation factor measurement data for the same cables

Adaptive Autocentering Control for an .Active Magnetic Bearing Supporting a Rotor with Unknown Mass Imbalance

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57790/1/LumAutocenteringTCST1996.pd

Parallel super-resolution imaging

Massive parallelization of scanning-based super-resolution imaging allows fast imaging of large fields of view

Gall Bladder Tumour, Choledochal Cyst and an Anomalous Pancreatico-Biliary Junction

This report highlights the association of a tumour in an acalculous gall bladder with an anomalous pancreatico-biliary junction (PBJ) and a type IVa choledochal cyst. Cholecystectomy and Rouxen- Y hepatico-jejunostomy (RHJ) was performed after division of the common bile duct (CBD) and excision of the dilated segment. The details of the case are presented and the role of an abnormal PBJ in gall bladder carcinogenesis is discussed

Serotonin 5-HT(2A )and 5-HT(6 )receptors in the prefrontal cortex of Alzheimer and normal aging patients

BACKGROUND: It has been hypothesized that alterations of the serotonergic system contribute to neuropsychiatric symptoms in Alzheimer disease (AD). Cellular expressions of the two serotonergic receptors 5-HT(2A )and 5-HT(6 )have therefore been determined by immunohistochemistry in the prefrontal cortex of patients with AD (n=6) and normal age-matched controls (n = 7). RESULTS: In normal aging patients, 5-HT(2A )label was mainly observed in large pyramidal cells, but to a lesser extent also in small pyramidal cells and in stellate cells of cortical layers II-VI. In AD, a similar distribution was observed, but density of positive cells was significantly reduced by 33%. In aging control patients, the 5-HT(6 )receptor was expressed by pyramidal cells and occasional stellate cells, not only of layers II-V, but also of layer I, where a distinct label was observed in neurons and surrounding fibers. 5-HT(6 )receptor expression in AD patients had the same pattern, but was significantly decreased by 40%. CONCLUSION: Our results indicate that a decline in neurons expressing 5-HT(2A), but also 5-HT(6 )receptors may play a role in the etiopathology of neuropsychiatric symptoms in AD

What Types of Feedback do Undergraduate Chemistry Students Give Each Other? A Case Study from Singapore

This study was part of a larger project to improve learning of undergraduate chemistry in Singapore through the use of self-authored three-tier multiple-choice questions (3TMCQs) and the giving/receiving of peer feedback. Specifically, we examined the quality of written feedback based on the classification by Hattie and Timperley (2007) that year 2 to 4 learners (N=31) gave each other on responses in their 3TMCQs (N=466 administered). It was found that the most common type of voluntary feedback given by test-makers was task (& self), followed by process (& self), self alone, and lastly regulation (& self) levels over seven chemistry courses. In addition, question type (based on revised Bloom’s Taxonomy) had a marginal effect on the quality of feedback received; instead, items answered incorrectly garnered higher quality feedback and were four times more important than the cognitive level of questions. Feedback quality given by more experienced students was also no better than those given by less experienced ones. While there is growing evidence supporting the self-authoring of questions and giving/receiving peer feedback to enhance learning at undergraduate levels, further research is warranted into the types of peer feedback that learners may receive when attempting different question formats

Protein mechanics probed using simple molecular models

Background: Single-molecule experimental techniques such as optical tweezers or atomic force microscopy are a direct probe of the mechanical unfolding/folding of individual proteins. They are also a means to investigate free energy landscapes. Protein force spectroscopy alone provides limited information; theoretical models relate measurements to thermodynamic and kinetic properties of the protein, but do not reveal atomic level information. By building a molecular model of the protein and probing its properties through numerical simulation, one can gauge the response to an external force for individual interatomic interactions and determine structures along the unfolding pathway. In combination, single-molecule force probes and molecular simulations contribute to uncover the rich behavior of proteins when subjected to mechanical force. Scope of review: We focus on how simplified protein models have been instrumental in showing how general properties of the free energy landscape of a protein relate to its response to mechanical perturbations. We discuss the role of simple protein models to explore the complexity of free energy landscapes and highlight important conceptual issues that more chemically accurate models with all-atom representations of proteins and solvent cannot easily address. Major conclusions: Native-centric, coarse-grained models, despite simplifications in chemical detail compared to all-atom models, can reproduce and interpret experimental results. They also highlight instances where the theoretical framework used to interpret single-molecule data is too simple. However, these simple models are not able to reproduce experimental findings where non-native contacts are involved. General significance: Mechanical forces are ubiquitous in the cell and it is increasingly clear that the way a protein responds to mechanical perturbation is important

Wide-field two-photon microscopy with temporal focusing and HiLo background rejection

Scanningless depth-resolved microscopy is achieved through spatial-temporal focusing and has been demonstrated previously. The advantage of this method is that a large area may be imaged without scanning resulting in higher throughput of the imaging system. Because it is a widefield technique, the optical sectioning effect is considerably poorer than with conventional spatial focusing two-photon microscopy. Here we propose wide-field two-photon microscopy based on spatio-temporal focusing and employing background rejection based on the HiLo microscope principle. We demonstrate the effects of applying HiLo microscopy to widefield temporally focused two-photon microscopy

Responses of Astrocytes in Culture After Low Dose Laser Irradiation

The effect of Helium-Neon low dose laser on astrocytes was investigated in cultures of isolated astrocytes from albino neonatal rats. The laser appeared to inhibit the growth of astrocytes as exemplified by the smaller sizes of the cells and the decreased leucine uptake in each cell after treatment. Temporary decrease in the number of mitoses was also observed, but this trend was reversed soon after. Electron microscopic studies revealed an increase in buddings from cell bodies and processes (branches) after irradiation