A floating sleeve antenna yields localized hepatic microwave ablation

We report a novel coaxial antenna for hepatic microwave ablation. This device uses a floating sleeve, that is, a metal conductor electrically isolated from the outer connector of the antenna coaxial body, to achieve a highly localized specific absorption rate pattern that is independent of insertion depth. This floating sleeve coaxial dipole antenna has low power reflection in the 2.4-GHz IMS band. Ex vivo experiments confirm our numerical simulation results. Index Terms-Ablation, coaxial aperture antennas, finite element methods, floating sleeve, microwave heating.     

3D Printed Stem‐Cell Derived Neural Progenitors Generate Spinal Cord Scaffolds

A bioengineered spinal cord is fabricated via extrusion‐based multimaterial 3D bioprinting, in which clusters of induced pluripotent stem cell (iPSC)‐derived spinal neuronal progenitor cells (sNPCs) and oligodendrocyte progenitor cells (OPCs) are placed in precise positions within 3D printed biocompatible scaffolds during assembly. The location of a cluster of cells, of a single type or multiple types, is controlled using a point‐dispensing printing method with a 200 µm center‐to‐center spacing within 150 µm wide channels. The bioprinted sNPCs differentiate and extend axons throughout microscale scaffold channels, and the activity of these neuronal networks is confirmed by physiological spontaneous calcium flux studies. Successful bioprinting of OPCs in combination with sNPCs demonstrates a multicellular neural tissue engineering approach, where the ability to direct the patterning and combination of transplanted neuronal and glial cells can be beneficial in rebuilding functional axonal connections across areas of central nervous system (CNS) tissue damage. This platform can be used to prepare novel biomimetic, hydrogel‐based scaffolds modeling complex CNS tissue architecture in vitro and harnessed to develop new clinical approaches to treat neurological diseases, including spinal cord injury.     

Relationships Between Structure and Activity in the α-Amylase Family of Starch-metabolising Enzymes

α-Amylases are known to be multidomain proteins, i.e., the molecules consist of several folding units. Each α-amylase is believed, however, to have a catalytic domain consisting, of a barrel of eight parallel α-strands surrounded by eight α-strands. with an extra helix inserted after the sixth γ-strands. The α-strands and helices alternate along the polypeptide chain and are linked together by irregular loops. Amino acid residues situated on the loops joining the C-terminal end of each α-strand to the N-terminal end of the following helix make up the active site of the enzymes. A similar structure has been found in cyclodextrin glucanotransfcrases and it is now believed that such a (α/α)8-barrel also constitutes the catalytic domain of enzymes active on α-1.6-glucosidic bonds, and of enzymes with dual specificity for both α-1.4- and α-1.6- bonds. Knowledge of the three-dimensional structure of α-amylases and cyclodextrin glucanotransferase has made possible identification of structural features important for enzymic activity and specificity. By analogy, some general conclusions are reached concerning pullulanase, isoamylase. oligo-1,6-glucosidase, neopullulanase and branching enzymes.     

Influence of medium-chain triglycerides on lipid metabolism in the rat

Lipid metabolism was studied in rats fed diets containing corn oil, coconut oil, or medium-chain triglyceride (MCT), a glyceride mixture containing fatty acids of 8 and 10 carbons in length. The ingestion of MCT-supplemented, cholesterolfree diets depressed plasma and liver total lipids and cholesterol as compared with corn oil-supplemented diets. In rats fed cholesterol-containing diets, plasma cholesterol levels were not influenced by dietary MCT, but liver cholesterol levels were significantly lower than in animals fed corn oil. In vitro cholesterol synthesis from acetate-1-¹⁴C was lower in liver slices of rats that consumed MCT than in similar preparations from corn oil-fed rats. Studies of fatty acid carboxyl labeling from acetate-1-¹⁴C and the conversion of palmitate-1-¹⁴C to C₁₈ acids by liver slices showed that chain-lengthening activity is greater in the liver tissue of rats fed MCT than in the liver of animals fed corn oil. The hepatic fatty acid desaturation mechanisms, evaluated by measuring the conversion of stearate-2-¹⁴C to oleate, was also enhanced by feeding MCT. Adipose tissue of rats fed MCT converts acetate-1-¹⁴C to fatty acids at a much faster rate than does tissue from animals fed corn oil. Evidence is presented to show that the enhanced incorporation of acetate into fatty acids by the adipose tissue of rats fed MCT represents de novo synthesis of fatty acids and not chain-lengthening activity. Data are also presented on the fatty acid composition of plasma, liver, and adipose tissue lipids of rats fed the different fats under study.     

Environmentally Smart Design: Designing for Social Wellbeing Across the City and in the Workplace

Sustainable need not mean more expensive. Health problems caused by sedentary lifestyles, pollution and injuries from road accidents come at great financial cost — not just for individuals, but also for employers and indeed national governments. Built environments designed to keep people active and away from harm are thus economically beneficial, too. Alisdair McGregor, Ann Marie Aguilar and Victoria Lockhart of Arup cite some of the company's recent schemes in New York and London that have successfully encouraged cycling, strolling and other healthy behaviours, while also avoiding contributing to climate change.     

Steerable Microinvasive Probes for Localized Drug Delivery to Deep Tissue

Enhanced understanding of neuropathologies has created a need for more advanced tools. Current neural implants result in extensive glial scarring and are not able to highly localize drug delivery due to their size. Smaller implants reduce surgical trauma and improve spatial resolution, but such a reduction requires improvements in device design to enable accurate and chronic implantation in subcortical structures. Flexible needle steering techniques offer improved control over implant placement, but often require complex closed‐loop control for accurate implantation. This study reports the development of steerable microinvasive neural implants (S‐MINIs) constructed from borosilicate capillaries (OD = 60 µm, ID = 20 µm) that do not require closed‐loop guidance or guide tubes. S‐MINIs reduce glial scarring 3.5‐fold compared to prior implants. Bevel steered needles are utilized for open‐loop targeting of deep‐brain structures. This study demonstrates a sinusoidal relationship between implant bevel angle and the trajectory radius of curvature both in vitro and ex vivo. This relationship allows for bevel‐tipped capillaries to be steered to a target with an average error of 0.23 mm ± 0.19 without closed‐loop control. Polished microcapillaries present a new microinvasive tool for chronic, predictable targeting of pathophysiological structures without the need for closed‐loop feedback and complex imaging.     

Narrating emotional events in schizophrenia.

Research has indicated that schizophrenia patients report similar amounts of experienced emotion in response to emotional material compared with nonpatients. However, less is known about how schizophrenia patients describe and make sense of their emotional life events. We adopted a narrative approach to investigate schizophrenia patients' renderings of their emotional life experiences. In Study 1, patients' (n = 42) positive and negative narratives were similarly personal, tellable, engaged, and appropriate. However, negative narratives were less grammatically clear than positive narratives, and positive narratives were more likely to involve other people than negative narratives. In Study 2, emotional (positive and negative) narratives were less tellable and detached, yet more linear and social compared with neutral narratives for both schizophrenia patients (n = 24) and healthy controls (n = 19). However, patients' narratives about emotional life events were less appropriate to context and less linear, and patients' narratives, whether emotional or not, were less tellable and more detached compared with controls' narratives. Although schizophrenia patients are capable of recounting life events that trigger different emotions, the telling of these life events is fraught with difficulty. (PsycINFO Database Record (c) 2010 APA, all rights reserved)