While virtually absent in our diet a few hundred years ago, fructose has now become a major constituent of our modern diet. Our main sources of fructose are sucrose from beet or cane, high fructose corn syrup, fruits, and honey. Fructose has the same chemical formula as glucose (C(6)H(12)O(6)), but its metabolism differs markedly from that of glucose due to its almost complete hepatic extraction and rapid hepatic conversion into glucose, glycogen, lactate, and fat. Fructose was initially thought to be advisable for patients with diabetes due to its low glycemic index. However, chronically high consumption of fructose in rodents leads to hepatic and extrahepatic insulin resistance, obesity, type 2 diabetes mellitus, and high blood pressure. The evidence is less compelling in humans, but high fructose intake has indeed been shown to cause dyslipidemia and to impair hepatic insulin sensitivity. Hepatic de novo lipogenesis and lipotoxicity, oxidative stress, and hyperuricemia have all been proposed as mechanisms responsible for these adverse metabolic effects of fructose. Although there is compelling evidence that very high fructose intake can have deleterious metabolic effects in humans as in rodents, the role of fructose in the development of the current epidemic of metabolic disorders remains controversial. Epidemiological studies show growing evidence that consumption of sweetened beverages (containing either sucrose or a mixture of glucose and fructose) is associated with a high energy intake, increased body weight, and the occurrence of metabolic and cardiovascular disorders. There is, however, no unequivocal evidence that fructose intake at moderate doses is directly related with adverse metabolic effects. There has also been much concern that consumption of free fructose, as provided in high fructose corn syrup, may cause more adverse effects than consumption of fructose consumed with sucrose. There is, however, no direct evidence for more serious metabolic consequences of high fructose corn syrup versus sucrose consumption.

http://www.perishablepundit.com/docs/fructose-and-obesity.pdf

Metabolic Effects of Fructose and the Worldwide Increase in Obesity

Digital x-ray tomosynthesis is a technique for producing slice images using conventional x-ray systems. It is a refinement of conventional geometric tomography, which has been known since the 1930s. In conventional geometric tomography, the x-ray tube and image receptor move in synchrony on opposite sides of the patient to produce a plane of structures in sharp focus at the plane containing the fulcrum of the motion; all other structures above and below the fulcrum plane are blurred and thus less visible in the resulting image. Tomosynthesis improves upon conventional geometric tomography in that it allows an arbitrary number of in-focus planes to be generated retrospectively from a sequence of projection radiographs that are acquired during a single motion of the x-ray tube. By shifting and adding these projection radiographs, specific planes may be reconstructed. This topical review describes the various reconstruction algorithms used to produce tomosynthesis images, as well as approaches used to minimize the residual blur from out-of-plane structures. Historical background and mathematical details are given for the various approaches described. Approaches for optimizing the tomosynthesis image are given. Applications of tomosynthesis to various clinical tasks, including angiography, chest imaging, mammography, dental imaging and orthopaedic imaging, are also described.

https://iopscience.iop.org/article/10.1088/0031-9155/48/19/R01/pdf

Digital x-ray tomosynthesis: current state of the art and clinical potential

Recent demand and interest in wireless, mobile-based healthcare has driven significant interest towards developing alternative biopotential electrodes for patient physiological monitoring. The conventional wet adhesive Ag/AgCl electrodes used almost universally in clinical applications today provide an excellent signal but are cumbersome and irritating for mobile use. While electrodes that operate without gels, adhesives and even skin contact have been known for many decades, they have yet to achieve any acceptance for medical use. In addition, detailed knowledge and comparisons between different electrodes are not well known in the literature. In this paper, we explore the use of dry/noncontact electrodes for clinical use by first explaining the electrical models for dry, insulated and noncontact electrodes and show the performance limits, along with measured data. The theory and data show that the common practice of minimizing electrode resistance may not always be necessary and actually lead to increased noise depending on coupling capacitance. Theoretical analysis is followed by an extensive review of the latest dry electrode developments in the literature. The paper concludes with highlighting some of the novel systems that dry electrode technology has enabled for cardiac and neural monitoring followed by a discussion of the current challenges and a roadmap going forward.

/pdf/dry-contact-and-noncontact-biopotential-electrodes-43xov09vpd.pdf

Dry-Contact and Noncontact Biopotential Electrodes: Methodological Review

For decades, exercise has been considered a cornerstone of diabetes management, along with diet and medication. However, high-quality evidence on the importance of exercise and fitness in diabetes was lacking until recent years. The last American Diabetes Association (ADA) technical review of exercise and type 2 diabetes (formerly known as non–insulin dependent diabetes) was published in 1990. The present work emphasizes the advances that have occurred since the last technical review was published.

Major developments since the 1990 technical review include: 

Based on this new evidence, we have refined the recommendations on the desired types, amounts, and intensities of aerobic physical activity for people with diabetes. Resistance training will now be recommended in a broader group of patients and at a broader range of intensity than done previously. There are other areas in which new evidence is lacking, but we feel that previous recommendations may have been more conservative than necessary. These areas include indications for exercise stress test before beginning an exercise program and precautions regarding …

https://care.diabetesjournals.org/content/diacare/27/10/2518.full.pdf

Physical activity/exercise and type 2 diabetes.

OBJECTIVE. We summarize how virtual monochromatic images are synthesized from dual-energy CT using image-domain and projection-domain methods. The quality of virtual monochromatic images is compared with that of polychromatic single-energy images acquired at different tube potentials and the same radiation dose. Clinical applications of dual-energy CT–based virtual monochromatic imaging are reviewed, including beam-hardening correction, contrast and noise optimization, metal artifact reduction, and material differentiation. CONCLUSION. Virtual monochromatic images synthesized from dual-energy CT data have the potential to reduce beam-hardening artifacts and to provide quantitative measurements. If there is no desire to obtain material-specific information or to correct for metal or beam-hardening artifacts from the dual-energy data, however, it is better to perform a conventional single-energy scan at the optimal tube potential.

https://www.ajronline.org/doi/pdfplus/10.2214/AJR.12.9121

Dual-Energy CT–Based Monochromatic Imaging

This paper presents a methodology for three-dimensional (3D) computer modelling of the breast, using a combination of 3D geometrical primitives and voxel matrices that can be further subjected to simulated x-ray imaging, to produce synthetic mammograms. The breast phantom is a composite model of the breast and includes the breast surface, the duct system and terminal ductal lobular units, Cooper's ligaments, the pectoral muscle, the 3D mammographic background and breast abnormalities. A second analytical x-ray matter interaction modelling module is used to generate synthetic images from monoenergetic fan beams. Mammographic images of various synthesized breast models differing in size, shape and composition were produced. A preliminary qualitative assessment performed by three radiologists and a quantitative evaluation study using fractal and grey-level histogram analysis were conducted. A comparative study of extracted features with published data has also been performed. The evaluation results indicated good correlation of characteristics between synthetic and actual radiographs. Applications foreseen are not only in the area of breast imaging experimentation but also in education and training.

https://iopscience.iop.org/article/10.1088/0031-9155/48/22/006/pdf

A three-dimensional breast software phantom for mammography simulation

In 13C02 breath tests, based on 13C:12C ratio measurements, the appearance of 13C in exhaled C02 was monitored after the administration of a 13C-la-belled compound. Independently of the substrate used, the existence of a bicarbonate pool into which the C02 produced enters before being exhaled, imposes a delay on the appearance of changes in the 13C:12C ratio. To estimate the nature and magnitude of this delay, we applied a two-compartment model to describe the kinetics of the body bicarbonate pool and we evaluated the 13C:12C ratio of C02 entering that pool from the measured 13C:12C ratio in the exhaled C02 after an oral intake of “naturally labelled” 13C-glucose. Our results demonstrated that discrepancies between total and exogenous glucose oxidation in relation to the peak occurrence time, as well as the absolute quantities, could be adequately explained by the interference of the bicarbonate stores.

Influence of the bicarbonate pool and on the occurrence of 13CO2 in exhaled air

The extent to which an oral load of glucose is absorbed from the gut and oxidized during prolonged exercise is a matter of controversy. Four healthy volunteers, 18–28 yr, were submitted on 4 differ...

Fate of exogenous glucose during exercise of different intensities in humans

A new method of optimized efficiency for the retrospective reconstruction of tomograms is presented. The method has been developed for use with isocentric fluoroscopic units and is capable of performing digital tomosynthesis of anatomical planes of user selected orientation and distance from the isocenter. Optimization of efficiency has been achieved by segmenting the reconstruction process into discrete transformations that are specific to groups of pixels, rather than performing pixel by pixel operations. These involve a number of projections of the acquired image matrices as well as parallel translations and summing. Application of this method has resulted in a significant reduction of computing time. The proposed algorithm has been experimentally tested on a radiotherapy simulator unit with the use of a phantom and the obtained results are reported and discussed.

A multiple projection method for digital tomosynthesis.

Purpose: This work presents an improved algorithm for the generation of 3D breast software phantoms and its evaluation for mammography Methods: The improved methodology has evolved from a previously presented 3D noncompressed breast modeling method used for the creation of breast models of different size, shape, and composition The breast phantom is composed of breast surface, duct system and terminal ductal lobular units, Cooper's ligaments, lymphatic and blood vessel systems, pectoral muscle, skin, 3D mammographic background texture, and breast abnormalities The key improvement is the development of a new algorithm for 3D mammographic texture generation Simulated images of the enhanced 3D breast model without lesions were produced by simulating mammographic image acquisition and were evaluated subjectively and quantitatively For evaluation purposes, a database with regions of interest taken from simulated and real mammograms was created Four experienced radiologists participated in a visual subjective evaluation trial, as they judged the quality of the simulated mammograms, using the new algorithm compared to mammograms, obtained with the old modeling approach In addition, extensive quantitative evaluation included power spectral analysis and calculation of fractal dimension, skewness, and kurtosis of simulated and real mammograms from the database Results: The results from the subjective evaluation stronglymore » suggest that the new methodology for mammographic breast texture creates improved breast models compared to the old approach Calculated parameters on simulated images such as {beta} exponent deducted from the power law spectral analysis and fractal dimension are similar to those calculated on real mammograms The results for the kurtosis and skewness are also in good coincidence with those calculated from clinical images Comparison with similar calculations published in the literature showed good agreement in the majority of cases Conclusions: The improved methodology generated breast models with increased realism compared to the older model as shown in evaluations of simulated images by experienced radiologists It is anticipated that the realism will be further improved using an advanced image simulator so that simulated images may be used in feasibility studies in mammography« less

/pdf/evaluation-of-an-improved-algorithm-for-producing-realistic-1i2pgflbd4.pdf

Nicolas Pallikarakis

Papers

A three-dimensional breast software phantom for mammography simulation

Influence of the bicarbonate pool and on the occurrence of 13CO2 in exhaled air

Fate of exogenous glucose during exercise of different intensities in humans

A multiple projection method for digital tomosynthesis.

Evaluation of an improved algorithm for producing realistic 3D breast software phantoms: Application for mammography