Physicochemical conversion of human exometabolites for the NaCl involvement into the mass exchange in closed life support systems

The results of the original physicochemical method of NaCl recovery out of the mineralized human metabolites’ solution obtained after their oxidation in H₂O₂ aqueous solution under the influence of alternating electric current are presented. The technological stages of the newly developed method are described, and its efficiency at each stage is demonstrated. The possibility to efficiency isolate Na from the NaHCO₃ solution by applying electrodialysis technology and temperature separation is demonstrated. The HCl synthesis from Cl₂ and H₂ released during electrolysis is stable, allowing its combining with electrodialysis aimed at NaCl production under the conditions of a closed life support system.     

On the Possibility of Correcting Pathology of the Peripheral Nervous System by Physical Factors Emerging during the Functioning of EPR,NMR, and NGR

Study of the mechanisms of influence of electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), and nuclear γ-resonance (NGR) on normal and pathological living systems is medically promising for development of new treatment methods. In addition, this approach may be used to search for materials for nerve prosthetics. These techniques may expand the range of modern experimental and clinical methods of diagnosing and treating a number of pathologies. The devices used may physically affect biochemical processes in the body in the EPR, NMR, and NGR regimes, simultaneously recording these processes. The use of these devices in pathology models may be helpful for correcting pathological processes, in particular, by strengthening conduction in the nerve-muscle preparation; they may also influence free radicals, which probably play a role in reducing conduction of nerve fibers. The treatment by EPR and NMR (NGR conditions) suggested here may also be used together with pharmacological or other methods.     

Multiple-axis tomography: applications to basal bodies from Paramecium tetraurelia

BACKGROUND INFORMATION: Transmission electron tomography is becoming a powerful tool for studying subcellular components of cells. Classical approaches for electron tomography consist of recording images along a single-tilt axis. This approach is being improved by dual-axis reconstructions and/or high-tilt devices (tilt angle>+/-60 degrees) on microscopes to compensate part of the information loss due to the 'missing wedge' phenomena. RESULTS: In the present work we have evaluated the extension of the dual-axis technique to a multiple-axis approach, and we demonstrate a freely available plug-in for the Java-based freeware image-analysis software ImageJ. Our results from phantom and experimental data sets from Paramecium tetraurelia epon-embedded sections have shown that multiple-axis tomography achieves results equivalent to those obtained by dual-axis approach without the requirement for high-tilt devices. CONCLUSIONS: This new approach allows performance of high-resolution tomography, avoiding the need for high-tilt devices, and therefore will increase the access of electron tomography to a larger community.     

Process development and optimisation of lactic acid purification using electrodialysis

Cell free sodium lactate solutions were subjected to purification based on mono- and bi-polar electrodialysis. Lactate concentration in the product stream increased to a maximum of 15% during mono-polar electrodialysis. Stack energy consumption averaged 0.6 kW h kg(-1) lactate transported at current efficiencies in the 90% range. Under optimum feed concentration (125 g l(-1)) and process conditions (auto-current mode with conductivity setpoints of minimum 5 and maximum 40 mS cm(-1)), lactate flux reached 300 g m(-2) h(-1) and water flux were low for mono-polar electrodialysis averaging 0.3 kg H(2)O per M lactate transported. Glucose in the concentrate stream solutions was reduced to < 2 g l(-1). Acetate impurities enriched from about 0.5 g l(-1) in the feed stream to 1.5 g l(-1) in the concentrate stream solutions. After mono-polar electrodialysis, the concentrated sodium lactate solutions were further purified using bi-polar electrodialysis. Water transport during bi-polar electrodialysis reached figures of 0.070 - 0.222 kg H(2)O per M lactate. Free lactic acid concentration reached 16% with lactate flux of up to 300 g m(-2) h(-1). Stack energy consumption ranged from 0.6 to 1 kW h per kg lactate. Under optimised process conditions current efficiency during bi-polar electrodialysis was consistently around 90%. Glucose was further reduced from 2 to <1 g l(-1) in the free lactic acid solution. Acetic acid impurity remained at around 1 g l(-1). Significant reduction in colour and minerals in the product streams was observed during electrodialysis purification.     

The nonlinear predictability of the electrotelluric field variations data analyzed with support vector machines as an earthquake precursor

This work investigates the nonlinear predictability of the Electro Telluric Field (ETF) variations data in order to develop new intelligent tools for the difficult task of earthquake prediction. Support Vector Machines trained on a signal window have been used to predict the next sample. We observe a significant increase at this short-term unpredictability of the ETF signal at about two weeks time period before the major earthquakes that took place in regions near the recording devices. The unpredictability increase can be attributed to a quick time variation of the dynamics that produce the ETF signal due to the earthquake generation process. Thus, this increase can be taken into advantage for signaling for an increased possibility of a large earthquake within the next few days in the neighboring region of the recording station.     

Integration of videooculography and encephalography for investigation of visual selective attention in humans

An original method of EEG recording in combination with eye tracking was developed. Due to the precise synchronization (which can include any amount of various recording devices), it is now possible to record short-time electrophysiological patterns evoked by some visual stimulus. The key feature of the method is the possibility to study not only single effects of a stimulus but to extract electrophysiological records corresponding to some part of complex image scanning.     

MRI and computerized tomography in the evaluation of lumbar spine after herniated disk surgery]

The authors analyze the results of comprehensive radio-diagnosis in 44 patients previously operated on for lumbar hernias. All the findings of magnetic resonance tomography and computer-aided tomography were divided into 3 groups: (1) natural consequences of a surgical intervention without clinical manifestations; (2) complications after a surgical intervention; (3) recurrent hernias or hernias on an adjacent level. The most intricate problem was the differential diagnosis between a recurrent hernia and a postoperative epidural cicatrix. Criteria to distinguish between these two conditions are suggested. The authors emphasize that the optimal variant for examination of the patients operated on is a combination of magnetic resonance tomography and computer-aided tomography.     

Comparative characteristics of radiation imaging methods in the diagnosis of sacroiliitis

Patients with sacroiliac joint, injuries, ankylosing spondyloarthritis, or spondyloarthropathy of various genesis were examined. Pelvis x-ray, spiral computed tomography (CT), and magnetic resonance imaging (MRI) were performed. MRI was found to have advantages in the detection and evaluation of the pattern of detectable bone changes. It is inexpedient to use traditional x-ray study and CT for the detection of edematous-infiltrative changes in both osseous and fibrous and soft tissue elements of the joint since the sensitivity of these techniques is insufficient to detect. To analyze detectable changes, it is expedient to use a unified MRI protocol that involves the characteristics of osseous, fibrous, and soft tissue structures of the joint.     

Are Human Peripheral Nerves Sensitive to X-Ray Imaging?

Diagnostic imaging techniques play an important role in assessing the exact location, cause, and extent of a nerve lesion, thus allowing clinicians to diagnose and manage more effectively a variety of pathological conditions, such as entrapment syndromes, traumatic injuries, and space-occupying lesions. Ultrasound and nuclear magnetic resonance imaging are becoming useful methods for this purpose, but they still lack spatial resolution. In this regard, recent phase contrast x-ray imaging experiments of peripheral nerve allowed the visualization of each nerve fiber surrounded by its myelin sheath as clearly as optical microscopy. In the present study, we attempted to produce high-resolution x-ray phase contrast images of a human sciatic nerve by using synchrotron radiation propagation-based imaging. The images showed high contrast and high spatial resolution, allowing clear identification of each fascicle structure and surrounding connective tissue. The outstanding result is the detection of such structures by phase contrast x-ray tomography of a thick human sciatic nerve section. This may further enable the identification of diverse pathological patterns, such as Wallerian degeneration, hypertrophic neuropathy, inflammatory infiltration, leprosy neuropathy and amyloid deposits. To the best of our knowledge, this is the first successful phase contrast x-ray imaging experiment of a human peripheral nerve sample. Our long-term goal is to develop peripheral nerve imaging methods that could supersede biopsy procedures.     

What can computed tomography and magnetic resonance imaging tell us about ventilation?

This review provides a summary of pulmonary functional imaging approaches for determining pulmonary ventilation, with a specific focus on multi-detector x-ray computed tomography and magnetic resonance imaging (MRI). We provide the important functional definitions of pulmonary ventilation typically used in medicine and physiology and discuss the fact that some of the imaging literature describes gas distribution abnormalities in pulmonary disease that may or may not be related to the physiological definition or clinical interpretation of ventilation. We also review the current state-of-the-field in terms of the key physiological questions yet unanswered related to ventilation and gas distribution in lung disease. Current and emerging imaging research methods are described, including their strengths and the challenges that remain to translate these methods to more wide-spread research and clinical use. We also examine how computed tomography and MRI might be used in the future to gain more insight into gas distribution and ventilation abnormalities in pulmonary disease.     

Multimodality molecular imaging of disease progression in living subjects

The enormous advances in our understanding of the progression of diseases at the molecular level have been supplemented by the new field of ‘molecular imaging’, which provides for in vivo visualization of molecular events at the cellular level in living organisms. Molecular imaging is a noninvasive assessment of gene and protein function, protein–protein interaction and/or signal transduction pathways in animal models of human disease and in patients to provide insights into molecular pathogenesis. Five major imaging techniques are currently available to assess the structural and functional alterations in vivo in small animals. These are (i) optical bioluminescence and fluorescence imaging techniques, (ii) radionuclide-based positron emission tomography (PET) and single photon emitted computed tomography (SPECT), (iii) X-ray-based computed tomography (CT), (iv) magnetic resonance imaging (MRI) and (v) ultrasound imaging (US). Functional molecular imaging requires an imaging probe that is specific for a given molecular event. In preclinical imaging, involving small animal models, the imaging probe could be an element of a direct (‘direct imaging’) or an indirect (‘indirect imaging’) event. Reporter genes are essential for indirect imaging and provide a general integrated platform for many different applications. Applications of multimodality imaging using combinations of bioluminescent, fluorescent and PET reporter genes in unified fusion vectors developed by us for recording events from single live cells to whole animals with high sensitivity and accurate quantification are discussed. Such approaches have immense potential to track progression of metastasis, immune cell trafficking, stem cell therapy, transgenic animals and even molecular interactions in living subjects.     

Recovery of lactic acid from fermentation broth by the two-stage process of nanofiltration and water-splitting electrodialysis

A two-stage process of nanofiltration and water-splitting electrodialysis was investigated for lactic acid recovery from fermentation broth. In this process, sodium lactate is isolated from fermentation broth in the first stage of nanofiltration by using an NTR-729HF membrane, and then is converted to lactic acid in the second stage by water-splitting electrodialysis. To determine the optimal operating conditions for nanofiltration, the effects of pressure, lactate concentration, pH and known added impurities were studied. Lactate rejection was less than 5%, magnesium rejection approximated 45%, and calcium rejection was at 40%. In subsequent water-splitting electrodialysis, both the sodium lactate conversion to lactic acid and sodium hydroxide recovery, were about 95%, with a power requirement of 0.9∼1.0 kWh per kg of lactate.     

A mechanical analysis of woodpecker drumming and its application to shock-absorbing systems

A woodpecker is known to drum the hard woody surface of a tree at a rate of 18 to 22 times per second with a deceleration of 1200 g, yet with no sign of blackout or brain damage. As a model in nature, a woodpecker is studied to find clues to develop a shock-absorbing system for micromachined devices. Its advanced shock-absorbing mechanism, which cannot be explained merely by allometric scaling, is analyzed in terms of endoskeletal structures. In this analysis, the head structures (beak, hyoid, spongy bone, and skull bone with cerebrospinal fluid) of the golden-fronted woodpecker, Melanerpes aurifrons, are explored with x-ray computed tomography images, and their shock-absorbing mechanism is analyzed with a mechanical vibration model and an empirical method. Based on these analyses, a new shock-absorbing system is designed to protect commercial micromachined devices from unwanted high-g and high-frequency mechanical excitations. The new shock-absorbing system consists of close-packed microglasses within two metal enclosures and a viscoelastic layer fastened by steel bolts, which are biologically inspired from a spongy bone contained within a skull bone encompassed with the hyoid of a woodpecker. In the experimental characterizations using a 60 mm smoothbore air-gun, this bio-inspired shock-absorbing system shows a failure rate of 0.7% for the commercial micromachined devices at 60?000 g, whereas a conventional hard-resin method yields a failure rate of 26.4%, thus verifying remarkable improvement in the g-force tolerance of the commercial micromachined devices.     

Magnetic resonance imaging in the assessment and surgical management of epilepsy and functional neurological disorders

Magnetic resonance imaging (MRI) offers significant advantages over computerized tomography (CT) and teleradiographic techniques when used for the evaluation and management of epilepsy and functional neurological disorders. Depth recording and radiofrequency electrodes can be more accurately positioned within structures such as the amygdala and hippocampus. The extent of corpus callosum section, lobectomy, topectomy, and radiofrequency stereotactic lesions can now be readily confirmed and related with seizure, neurological, and behavioral outcome. Occult, usually low grade, intraparenchymal neoplasms not visualized on CT scans can be located by MRI and biopsied or excised by MRI stereotactic techniques.     

Possible mechanisms of information interactions in molecular physico-biological systems]

Cooperative mechanisms of information transfer in molecular physico-biological systems are suggested. Expressions for probability of cooperative emission from interacting molecules having quite definite information about the character of distribution of molecules inside the system are derived. The suggested mechanisms of information transfer on the atomic-molecular level will possibly allow to understand better and to describe adequately many interesting phenomena considered by molecular biology and molecular psychobiology in particular. Appendix: Throbbing in cooperative luminescence for triads of molecules combined with each other by weak interaction.     

Utilizing the Metallic Nano-Rods in Hexagonal Configuration to Enhance Sensitivity of the Plasmonic Racetrack Resonator in Sensing Application

A high sensitive plasmonic refractive index sensor based on metal-insulator-metal (MIM) waveguides with embedding metallic nano-rods in racetrack resonator has been proposed. The refractive index changes of the dielectric material inside the resonator together with temperature changes can be acquired from the detection of the resonance wavelength, based on their linear relationship. With optimum design and considering a tradeoff among detected power, structure size, and sensitivity, the finite difference time domain simulations show that the refractive index and temperature sensitivity values can be obtained as high as 2610 nm per refractive index unit (RIU) and 1.03 nm/°C, respectively. In addition, resonance wavelengths of resonator are obtained experimentally by using the resonant conditions. The effects of nano-rods radius and refractive index of racetrack resonator are studied on the sensing spectra, as well. The proposed structure with such high sensitivity will be useful in optical communications that can provide a new possibility for designing compact and high-performance plasmonic devices.     

Magnetic Resonance Imaging Part II—Clinical Applications

Magnetic resonance (MR) imaging is the most promising new technology to appear in the clinical imaging arena since the advent of x-ray transmission computed tomography in the early 1970s. Five independent tissue characteristics (spin density, spin-lattice and spin-spin relaxation times, flow and spectral shift information) are accessible to MR imaging, and their relative influence in the magnetic resonance image can be varied by appropriate selection of pulse sequences and pulse times. All major organ systems appear to be amenable to MR imaging, and some are revealed with superior definition compared with their appearance in images obtained by alternate imaging technologies. Of particular interest is the superior contrast resolution in MR images of the brain and spinal cord, and the absence of bone- and motion-induced artifacts in images of the abdomen and pelvis. Applications of MR imaging to the heart and great vessels are just developing, as are new types of contrast agents for use in MR imaging. In vivo chemical spectroscopic measurements by magnetic resonance are heralded by some investigators as the most significant contribution that magnetic resonance will make ultimately to clinical diagnosis.At present, the number of MR imaging units is extremely low, and clinical studies are proceeding at a slow rate. Nevertheless, it is possible to provide a preliminary evaluation of the usefulness of MR imaging in a variety of clinical applications. This article is such an evaluation, tempered by the acknowledgement that much additional work remains to be done.     

Molecular modeling of nearly full-length ErbB2 receptor

Members of the epidermal growth factor receptor family play important roles in various cellular processes, both in physiological and in pathological conditions. Dimerization and autophosphorylation of these receptor tyrosine kinases are key events of signal transduction. Details of the molecular events of the signaling are not entirely known. To facilitate the understanding of receptor structure and function at the molecular level, a molecular model was built for the nearly full-length ErbB2 dimer. Modeling was based on the x-ray or nuclear-magnetic resonance structures of extracellular, transmembrane, and intracellular domains. The extracellular domain was positioned above the cell membrane based on the distance determined from experimentally measured fluorescence resonance energy transfer. Favorable dimerization interactions are predicted for the extracellular, transmembrane, and protein kinase domains in the model of a nearly full-length dimer of ErbB2, which may act in a coordinated fashion in ErbB2 homodimerization, and also in heterodimers of ErbB2 with other members of the ErbB family.     

Imaging of Metastatic Lymph Nodes by X-ray Phase-Contrast Micro-Tomography

Invasive cancer causes a change in density in the affected tissue, which can be visualized by x-ray phase-contrast tomography. However, the diagnostic value of this method has so far not been investigated in detail. Therefore, the purpose of this study was, in a blinded manner, to investigate whether malignancy could be revealed by non-invasive x-ray phase-contrast tomography in lymph nodes from breast cancer patients. Seventeen formalin-fixed paraffin-embedded lymph nodes from 10 female patients (age range 37–83 years) diagnosed with invasive ductal carcinomas were analyzed by X-ray phase-contrast tomography. Ten lymph nodes had metastatic deposits and 7 were benign. The phase-contrast images were analyzed according to standards for conventional CT images looking for characteristics usually only visible by pathological examinations. Histopathology was used as reference. The result of this study was that the diagnostic sensitivity of the image analysis for detecting malignancy was 100% and the specificity was 87%. The positive predictive value was 91% for detecting malignancy and the negative predictive value was 100%. We conclude that x-ray phase-contrast imaging can accurately detect density variations to obtain information regarding lymph node involvement previously inaccessible with standard absorption x-ray imaging.