Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories

Holographic subsurface radar (HSR) is not currently in widespread usage. This is due to a historical perspective in the ground-penetrating radar (GPR) community that the high attenuation of electromagnetic waves in most media of interest and the inability to apply time-varying gain to the continuous-wave (CW) HSR signal preclude sufficient effective penetration depth. While it is true that the fundamental physics of HSR, with its use of a CW signal, does not allow amplification of later (i.e., deeper) arrivals in lossy media (as is possible with impulse subsurface radar (ISR)), HSR has distinct advantages. The most important of these is the ability to do shallow subsurface imaging with a resolution that is not possible with ISR. In addition, the design of an HSR system is simpler than for ISR due to the relatively low-tech transmitting and receiving antennae. This paper provides a review of the main principles of HSR through an optical analogy and describes possible algorithms for radar hologram reconstruction. We also present a review of the history of development of systems and applications of the RASCAN type, which is possibly the only commercially available holographic subsurface radar. Among the subsurface imaging and remote sensing applications considered are humanitarian demining, construction inspection, nondestructive testing of dielectric aerospace materials, surveys of historic architecture and artworks, paleontology, and security screening. Each application is illustrated with relevant data acquired in laboratory and/or field experiments

Measurements of Elastic Moduli of Silicone Gel Substrates with a Microfluidic Device

Thin layers of gels with mechanical properties mimicking animal tissues are widely used to study the rigidity sensing of adherent animal cells and to measure forces applied by cells to their substrate with traction force microscopy. The gels are usually based on polyacrylamide and their elastic modulus is measured with an atomic force microscope (AFM). Here we present a simple microfluidic device that generates high shear stresses in a laminar flow above a gel-coated substrate and apply the device to gels with elastic moduli in a range from 0.4 to 300 kPa that are all prepared by mixing two components of a transparent commercial silicone Sylgard 184. The elastic modulus is measured by tracking beads on the gel surface under a wide-field fluorescence microscope without any other specialized equipment. The measurements have small and simple to estimate errors and their results are confirmed by conventional tensile tests. A master curve is obtained relating the mixing ratios of the two components of Sylgard 184 with the resulting elastic moduli of the gels. The rigidity of the silicone gels is less susceptible to effects from drying, swelling, and aging than polyacrylamide gels and can be easily coated with fluorescent tracer particles and with molecules promoting cellular adhesion. This work can lead to broader use of silicone gels in the cell biology laboratory and to improved repeatability and accuracy of cell traction force microscopy and rigidity sensing experiments

Midhumeral blockade for non-obstetric surgery during pregnancy [Gebelikte obstetrik disli cerrahi girişim IIçin midhumeral blok uygulamasi]

Operations during pregnancy and the anesthesia applied during these operations are very important in terms of morbidity and mortality since they have effects on both the mother and the fetus. Application of regional block is highly preferable when considering the risk of hypoxemia and aspiration and the side effects they create both on the mother and the fetus. However, peripheral blocks are not as common as central blocks. A Twenty week pregnant, 28 year old, woman, 83 kg in weight, with a history of cesarean section under general anesthesia was planned to have an operation due to the right distal humerus fracture of the gestational weight. The decision was made to block the Midhumeral axles. A total of 40 cc 0.25% bupivakain solution was injected in equal dose around each nerve in order to prevent median, radial, unlar and tourniquet pain respectively with 2mA current. There was no complications and no additional analgesic medication was needed. Considering the physiological changes of the pregnant woman, we believe that the peripheral nerve block performed by an experienced anesthesiologist may be more advantageous both for the safety of the pregnancy and for the fetus than applying general anesthesia

A variable block insertion heuristic for permutation flowshops with makespan criterion

This paper proposes a populated variable block insertion heuristic (PVBIH) algorithm for solving the permutation flowshop scheduling problem with the makespan criterion. The PVBIH algorithm starts with a minimum block size being equal to one. It removes a block from the current solution and inserts it into the partial solution randomly with a predetermined move size. A local search is applied to the solution found after several block moves. If the new solution generated after the local search is better than the current solution, it replaces the current solution. It retains the same block size as long as it improves. Otherwise, the block size is incremented by one and a simulated annealing-type of acceptance criterion is used to accept the new solution. This process is repeated until the block size reaches at the maximum block size. In addition, we present a randomized profile fitting heuristic with excellent results. Extensive computational results on the Taillard's well-known benchmark suite show that the proposed PVBIH algorithm substantially outperforms the differential evolution algorithm (NS-SGDE) recently proposed in the literature. © 2017 IEEE

Myastenia gravis and anesthesia management [Miyastenia gravis ve anestezi yönetimi]

Myasthenia Gravis (MG) is a muscle disease affecting the neuromuscular junction and characterised by weakness of skeletal muscle. Although, MG is rarely in society, it is a special research area for the clinicians and one of the important headings which anesthesiologists interested in. Nowadays the disease still have a challenge in the anesthesiology community because the pathophysiological consequences of the disease are closely associated with to many drugs like muscle relaxants. The mechanism and the management of the disease which is also triggered by stress factors, should have particularly known by all the anesthesiologists, because of the risk of postoperative respiratory failure. In this review, we aimed to increase awareness of the clinicians about the anesthetic approach to the management of MG disease

Evolution of Hierarchical Structures in Polyelectrolyte–Micelle Coacervates

We investigated the temperature-induced liquid–liquid phase separation (coacervation) of polyelectrolyte (PE)–micelle systems and the structure of the resultant coacervates. Dynamic light scattering, small angle neutron scattering and cryo-transmission electron microscopy (DLS, SANS, Cryo-TEM) were used to examine the evolution of complex structure up to the point of temperature-induced coacervation and beyond. Three diffusional modes, seen in the single phase samples and in the coexisting coacervated supernatant phases were attributed respectively to free micelles, PE–micelle complexes, and aggregates thereof. They corresponded to SANS Guinier region slopes yielding Rg [similar] 4 nm (micelles) and Rg [similar] 50 nm (unresolved complexes and aggregates). Cryo-TEM images of coacervates indicated how these subunits are organized within dense and dilute coacervate domains at larger length scales. Taken together, these results are understood to arise from the requirements of overall charge neutralization, and ion-pairing and counterion release during coacervation. We conclude that a polyelectrolyte:micelle system at incipient coacervation with charge stoichiometry ([+]/[−] \u3e 1) donates excess polycations to other complexes in solution. In the coacervate, a similar disproportionation but at different length scales ejects excess polycations and their counterions into dilute domains. In both phases, association and desolvation are driven by counterion release, enhanced chain configurational entropy, and ion-pairing. These enthalpic and entropic forces operating in both phases could explain the structural similarities between soluble aggregates and coacervate dense domains